fluorescence

摘要： The explosive growth of the global data volume demands new and advanced data storage methods.Here,we report that data storage with ultrahigh capacity(~1 TB per disc)can be realized in low-cost plastics,including polycarbonate(PC),precipitated calcium carbonate(PCC),polystyrene(PS),and polymethyl methacrylate(PMMA),via direct fs laser writing.The focused fs laser can modify the fluorescence of written regions on the surface and in the interior of PMMA,enabling threedimensional(3D)information storage.Through the 3D laser processing platform,a 50-layer data record with low bit error(0.96%)is archived.Visual reading of data is empowered by the fluorescence contrast.The broad variation of fluorescence intensity assigns 8 gray levels,corresponding to 3 bits on each spot.The gray levels of each layer present high stability after longterm aging cycles,confirming the robustness of data storage.Upon single pulse control via a high-frequency electro-optic modulator(EOM),a fast writing speed(~1 kB/s)is achieved,which is limited by the repetition frequency of the fs laser.

摘要： The optical nonlinearity in polycrystalline zinc selenide(ZnSe),excited with 775 nm,1 kHz femtosecond laser pulses was investigated via the nonlinear transmission with material thickness and the Z scan technique.The measured two photon absorption coefficientβwas intensity dependent,inferring that reverse saturated absorption(RSA)is also relevant dur-ing high intensity excitation in ZnSe.At low peak intensity I<5 GW cm^(-2),we findβ=3.5 cm GW^(-1) at 775 nm.The spec-tral properties of the broad blueish two-photon induced fluorescence(460 nm-500 nm)was studied,displaying self-ab-sorption near the band edge while the upper state lifetime was measured to be τ_(e)~3.3 ns.Stimulated emission was ob-served when pumping a 0.5 mm thick polycrystalline ZnSe sample within an optical cavity,confirmed by significant line narrowing fromΔλ=11 nm(cavity blocked)toΔλ=2.8 nm at peak wavelength λ_(p)=475 nm while the upper state life-time also decreased.These results suggest that with more optimum pumping conditions and crystal cooling,polycrystal-line ZnSe might reach lasing threshold via two-photon pumping atλ=775 nm.

摘要： Near infrared fluorescence using indocyanine green is beneficial for visual assessment of blood vessels,blood flow,and tissue perfusion,sentinel lymph node biopsy,lymph node road mapping,identification of the vascular system round the major vessels,and the detection of ureters in order to reduce the risk of iatrogenic ureteral lesions in colorectal surgery.

摘要： Salt marshes are research hotspots of the carbon cycle in coastal zones because large amounts of atmospheric carbon dioxide is fi xed by salt marshes vegetation and stored in its biomass and soil.Dissolved organic carbon(DOC)in submarine groundwater(well water and pore water)in salt marshes plays an important role in advective exchange between the salt marshes and coastal waters.However,the molecular characteristics of DOC in salt marsh groundwater are poorly understood because of the complex DOC structures and hydrodynamic process.In this study,fl uorescent components and refractory DOC(RDOC)in submarine groundwater from a salt marsh(Chongming Island,China)and adjacent coastal water were characterized by fl uorescence spectroscopy and nuclear magnetic resonance spectroscopy.The fl uorescent components identifi ed by parallel factor analysis indicated that humic-like substances dominated the chromophoric dissolved organic matter in the submarine groundwater.The chromophoric dissolved organic matter and dissolved organic matter in the submarine groundwater had non-conservative behaviors because of additions from terrestrial humic substances.The nuclear magnetic resonance spectra indicated that bioactive substances(carbohydrates)contributed only 13.2%-14.8%of the dissolved organic matter in the submarine groundwater but carboxyl-rich alicyclic molecules(CRAMs),the main components of RDOC,contributed 64.5%of the dissolved organic matter.Carbohydrates and CRAMs contributed 16.4%and 61.7%of the dissolved organic matter in the coastal water,similar to the contributions for submarine groundwater.The DOC concentration in submarine groundwater was 386±294μmol/L,which was signifi cantly higher than that in coastal water(91±19μmol/L).The high DOC concentrations and>60%relative RDOC content suggested that submarine groundwater may be an important source of RDOC to coastal seawater.This information will be helpful for estimating the climate eff ects of salt marsh blue carbon.

摘要： Introduction: Local anesthetics (LAs) must be adsorbed to and permeate through membranes to reach their sites of action. The rates of these processes critically affect drug actions at the cellular level and also the in vivo pharmacokinetics of perineurally injected drugs. Therefore, we measured the adsorption equilibria and permeation kinetics of two LAs local anesthetics with markedly different hydrophobicities: tetracaine (TTC, Poctanol:buffer = 3.6 × 103) and procaine (PRO, Poctanol:buffer = 8.1 × 101), in unilamellar membranes of different composition and fluidity. Methods: Interactions with unilamellar vesicles made of dipalmitoylphosphatidylcholine (DPPC), at 23°C (solid gel state) or 45°C (liquid crystal state), without or with cholesterol (Chol), were investigated by a combination of fluorescence and stopped-flow techniques. Membrane adsorption was monitored by the LA’s fluorescence. Membrane permeation was monitored by the decrease of fluorescence intensity of intra-vesicular pyranine, when quenched by neighboring TTC or PRO. Results: Ionized TTC (TTCH+) and procaine (PROH+) adsorb to membranes more slowly and weakly than their neutral counterparts (time constant τ ~ 0.1 sec). Fluidizing of membranes, at the higher temperature (45°C) or by Chol inclusion, accelerated LA adsorption (faster than the mixing time of the stopped-flow device, 0.008 s). Permeation of protonated TTCH+ through the solid gel DPPC membranes (23°C) occurred far more slowly than adsorption, (τ = 36.7 ± 0.7 s, n = 9), and 3 times slower than neutral TTC (τ = 10.9 ± 0.7 s, n = 9);neutral PRO permeated these membranes at the same rate as TTC. Inclusion of Chol with DPPC, disordering the fatty acyl tails of membrane phospholipids while crowding their polar headgroups, slowed permeation of TTC and of PRO to an even greater degree. Conclusions: Local anesthetic permeation through membranes is limited by the transport across the membrane core and not by the initial binding. Drug ionization greatly slows permeation, but greater hydrophobicity does not facilitate it. Lipid crowding caused by Chol, a normal membrane component, slows permeation by disorienting the LA bound at the surface.

摘要： Sodium acid phthalate C8H5NaO4 is one of the suitable semiorganic single crystals hired in second harmonic generation conversion applications. In the present work, optically transparent Benzophenone doped with sodium acid phthalate (SAPB) single crystals were grown successfully by slow evaporation solution technique. Single crystal XRD analyses exposed that the crystal lattice of SAPB crystal is a monoclinic crystal system with unit cell parameters a = 6.77 Å, b = 9.31 Å, c = 13.58 Å, and space group B2cb. The crystalline nature of SAPB material was confirmed by powder XRD pattern. The functional groups present in the grown crystals were identified by the FTIR analysis ranging between 4000 and 500 cm−1. The optical transparency and band gap of grown crystals were measured from UV-Visible spectroscopy. The fluorescence emission spectrum of the SAPB crystal having a strong Yellow emission peak at 574 nm and the red emission at 631 nm are identified. The Vickers microhardness number (Hv) increases with increasing load. Meyer’s index number (n) calculated from Hv shows that the material belongs to the soft material category. Preliminary measurement using Kurtz powder technique with Nd-YAG laser light of wavelength 1064 nm indicates that their second harmonic generation (SHG) efficiencies of the grown crystals were presented 2 times in comparison with Potassium Dihydrogen Phosphate (KDP) was confirmed.

摘要： Cadmium(Cd),a life threatening hazardous heavy metal is abundant in nature.Cd amounts are greater in leaves than other plant parts,and it shows considerable effects on photosynthesis.Nitric oxide(NO),a free radical present in living organisms,is now known as an important signaling molecule playing various physiological processes in plants.In this study,the possible ameliorative effect of NO on photosynthesis was examined on pea seedlings grown under Cd stress.Results showed that chlorophyll,net photosynthetic rate,transpiration rate,stomatal conductance,photochemical efficiency of Photosystem II and Photosystem I decreased,and Fo and nonphotochemical parameters for PSII and PSI significantly increased due to Cd stress.This suggests that Cd affects the photochemistry efficiency at both the PSII and PSI levels.Nitric oxide supplementation through SNP ameliorated Cd stress by enhancing all the above mentioned parameters but causing a reduction in the Fo,and non-photochemical parameters of PSII and PSI in pea plants.These data indicate that the exogenous application of NO was useful in mitigating Cd-induced damage to photosynthesis in pea seedling.

摘要： BACKGROUND Photodynamic therapy(PDT)is a minimally invasive form of cancer therapy,and the development of a novel photosensitizer(PS)with optimal properties is important for enhancing PDT efficacy.Folate receptor(FR)membrane protein is frequently overexpressed in 40%of human cancer and a good candidate for tumor-specific targeting.Specific active targeting of PS to FR can be achieved by conjugation with the folate moiety.A folate-linked,near-infrared(NIR)-sensitive probe,folate-Si-rhodamine-1(FolateSiR-1),was previously developed and is expected to be applicable to NIR-PDT.AIM To investigate the therapeutic efficacy of NIR-PDT induced by FolateSiR-1,a FRtargeted PS,in preclinical cancer models.METHODS FolateSiR-1 was developed by conjugating a folate moiety to the Si-rhodamine derivative through a negatively charged tripeptide linker.FR expression in the designated cell lines was examined by western blotting(WB).The selective binding of FolateSiR-1 to FR was confirmed in FR overexpressing KB cells(FR+)and tumors by fluorescence microscopy and in vivo fluorescence imaging.Low FR expressing OVCAR-3 and A4 cell lines were used as negative controls(FR-).The NIR light(635±3 nm)-induced phototoxic effect of FolateSiR-1 was evaluated by cell viability imaging assays.The time-dependent distribution of FolateSiR-1 and its specific accumulation in KB tumors was determined using in vivo longitudinal fluorescence imaging.The PDT effect of FolateSiR-1 was evaluated in KB tumor bearing mice divided into four experimental groups:(1)FolateSiR-1(100μmol/L)alone;(2)FolateSiR-1(100μmol/L)followed by NIR irradiation(50 J/cm2);(3)NIR irradiation(50 J/cm2)alone;and(4)no treatment.Tumor volume measurement and immunohistochemical(IHC)and histological examinations of the tumors were performed to analyze the effect of PDT.RESULTS High FR expression was observed in the KB cells by WB,but not in the OVCAR-3 and A4 cells.Substantial FR-specific binding of FolateSiR-1 was observed by in vitro and in vivo fluorescence imaging.Cell viability imaging assays showed that NIR-PDT induced cell death in KB cells.In vivo longitudinal fluorescence imaging showed rapid peak accumulation of FolateSiR-1 in the KB tumors 2 h after injection.In vivo PDT conducted at this time point caused tumor growth delay.The relative tumor volumes in the PDT group were significantly reduced compared to those in the other groups[5.81±1.74(NIR-PDT)vs 12.24±2.48(Folate-SiR-1),vs 11.84±3.67(IR),vs 12.98±2.78(Untreated),at Day 16,P<0.05].IHC analysis revealed reduced proliferation marker Ki-67-positive cells in the PDT treated tumors,and hematoxylin-eosin staining revealed features of necrotic-and apoptotic cell death.CONCLUSION FolateSiR-1 has potential for use in PDT,and FR-targeted NIR-PDT may open a new effective strategy for the treatment of FR-overexpressing tumors.

摘要： Rhodamine 6G-chromone-derived compounds RD1 - RD4 have been synthesized by condensation of rhodamine 6G hydrazide and substituted chromone aldehydes in ethanol using microwave-assisted reaction. The structures of these synthesized rhodamine 6G derivatives were confirmed by proton nuclear magnetic resonance (1H-NMR), carbon nuclear magnetic resonance (13C-NMR), and high-resolution mass spectra data (HRMS). Colorimetric and photophysical studies show the synthesized compounds selectively detect copper (II) ion in aqueous acetonitrile solution.

摘要： The in-situ post-embolization fluorescence-guided hepatectomy for hepatocellular carcinoma(HCC) requires precise embolic formulation that meets both preoperative and intraoperative needs of hepatobiliary surgeons.In this Editorial,we highlight the development of Superstable Homogeneous Iodinated Formulation Technology(SHIFT) for locoregional HCC treatment.It is believed that such an intelligent solution could resolve unmet formulation needs and make a major stride to bridge the preoperative gap of precision hepatectomy.