A novel lactate dehydrogenase-based risk score model to predict the prognosis of primary central nervous system germ cell tumor treated with chemoradiotherapy.

BACKGROUND: The prognostic role of lactate dehydrogenase (LDH) has been confirmed in many malignant tumors, but the role of serum LDH in primary central nervous system germ cell tumor (GCT) remains unknown. This study aimed to assess the prognostic value of LDH in GCT patients and develop a nomogram to predict prognosis in patients undergoing chemoradiotherapy. METHODS: A total of 161 patients with GCT were included in this study. Using a restricted cubic spline (RCS) model, the optimal cutoff point for LDH was determined to be 217 U/L. The survival of GCT patients was evaluated using the Kaplan-Meier method and log-rank test to analyze the effects of LDH levels. Univariate Cox regression, multivariate Cox regression, and LASSO Cox regression were conducted to identify prognostic factors, which were incorporated into a nomogram for predicting overall survival (OS). The predictive accuracy of the nomogram was assessed using the C-index, calibration curve, area under the time-dependent receiver operating characteristic curve (time-dependent AUC), and risk group stratification. The net benefits of the nomogram at different threshold probabilities were quantified using decision curve analysis (DCA). RESULTS: The high-LDH group had significantly shorter OS compared to the low-LDH group (P = 0.016). Based on the SYSUCC cohort, three variables were shown to be significant factors for OS and were incorporated in the nomogram: LDH, histopathology, and dissemination. It showed good discrimination ability, with C-index of 0.789 (95% CI, 0.671-0.907). Additionally, the clinical usefulness of the nomogram was confirmed by calibration curves and time-dependent AUC. DCA further highlighted the potential of the nomogram to guide clinical treatment strategies for patients. Moreover, there was a significant difference in OS among patients categorized into different risk groups (P < 0.001). CONCLUSION: LDH levels may serve as a reliable predictor for assessing the therapeutic effect of chemoradiotherapy in GCT. The developed nomogram exhibits high accuracy in predicting survival outcomes, aiding in the classification of prognostic groups, and supporting informed clinical decision-making.

Magnetic plasmon formation and propagation in artificial aromatic molecules.

The plasmonic properties of coupled metallic nanostructures are understood through the analogy between their collective plasmon modes and the electronic orbitals of corresponding molecules. Here we expand this analogy to planar arrangements of plasmonic nanostructures whose magnetic plasmons directly resemble the delocalized orbitals of aromatic hydrocarbon molecules. The heptamer structure serves as a benzene-like building block for a family of plasmonic artificial aromatic analogs with fused ring structures. Antiphase magnetic plasmons are excited in adjacent fused heptamer units, which for a linear multiheptamer structure is a behavior controlled by the number of units in the structure. This antiphase coupling gives rise to plasmonic "antiferromagnetic" behavior in multiple repeated heptamer structures, supporting the propagation of low-loss magnetic plasmons in this new waveguide geometry.

Plasmonic mode engineering with templated self-assembled nanoclusters.

Plasmonic nanoparticle assemblies are a materials platform in which optical modes, resonant frequencies, and near-field intensities can be specified by the number and position of nanoparticles in a cluster. A current challenge is to achieve clusters with higher yields and new types of shapes. In this Letter, we show that a broad range of plasmonic nanoshell nanoclusters can be assembled onto a lithographically defined elastomeric substrate with relatively high yields using templated assembly. We assemble and measure the optical properties of three cluster types: Fano-resonant heptamers, linear chains, and rings of nanoparticles. The yield of heptamer clusters is measured to be over 30%. The assembly of plasmonic nanoclusters on an elastomer paves the way for new classes of plasmonic nanocircuits and colloidal metamaterials that can be transfer-printed onto various substrate media.

Near-normal incidence dark-field microscopy: applications to nanoplasmonic spectroscopy.

The spectroscopic characterization of individual nanostructures is of fundamental importance to understanding a broad range of physical and chemical processes. One general and powerful technique that addresses this aim is dark-field microscopy, with which the scattered light from an individual structure can be analyzed with minimal background noise. We present the spectroscopic analysis of individual plasmonic nanostructures using dark-field illumination with incidence nearly normal to the substrate. We show that, compared to large incidence angle approaches, the near-normal incidence approach provides significantly higher signal-to-background ratios and reduced retardation field effects. To demonstrate the utility of this technique, we characterize an individual chemically synthesized gold nanoshell and a lithographically defined heptamer exhibiting a pronounced Fano-like resonance. We show that the line shape of the latter strongly depends on the incidence angle. Near-normal incidence dark-field microscopy can be used to characterize a broad range of molecules and nanostructures and can be adapted to most microscopy setups.

Substrate-induced Fano resonances of a plasmonic nanocube: a route to increased-sensitivity localized surface plasmon resonance sensors revealed.

Symmetry-breaking introduced by an adjacent semi-infinite dielectric can introduce coupling and hybridization of the plasmon modes of a metallic nanostructure. This effect is particularly large for entities with a large contact area adjacent to the dielectric. For a nanocube, a nearby dielectric mediates an interaction between bright dipolar and dark quadrupolar modes, resulting in bonding and antibonding hybridized modes. The Fano resonance that dominates the scattering spectrum arises from the interference of these modes. This analysis provides a strategy for optimizing the sensitivity of nanostructures, whether chemically synthesized or grown by deposition methods, as high-performance localized surface plasmon resonance sensors.

Unidirectional broadband light emission from supported plasmonic nanowires.

Metal nanowires are thought to become key elements in future nanophotonics applications. Here we show that single crystal silver nanowires supported on a dielectric interface behave similar to broadband unidirectional antennas for visible light. The degree of directionality can be controlled through the nanowire radius and its dielectric environment and the effect can be interpreted in terms of so-called leakage radiation from surface plasmons propagating in a single direction along a wire. We measure a forward-to-backward emission ratio exceeding 15 dB and an angular spread of 4° for wires with radii of the order 150 nm on glass in air. These findings could pave the way for development of metal nanowires as subwavelength directors of light in solar, sensor, and spectroscopy applications.

DNA-enabled self-assembly of plasmonic nanoclusters.

DNA nanotechnology provides a versatile foundation for the chemical assembly of nanostructures. Plasmonic nanoparticle assemblies are of particular interest because they can be tailored to exhibit a broad range of electromagnetic phenomena. In this Letter, we report the assembly of DNA-functionalized nanoparticles into heteropentamer clusters, which consist of a smaller gold sphere surrounded by a ring of four larger spheres. Magnetic and Fano-like resonances are observed in individual clusters. The DNA plays a dual role: it selectively assembles the clusters in solution and functions as an insulating spacer between the conductive nanoparticles. These particle assemblies can be generalized to a new class of DNA-enabled plasmonic heterostructures that comprise various active and passive materials and other forms of DNA scaffolding.

Chiral surface plasmon polaritons on metallic nanowires.

Chiral surface plasmon polaritons (SPPs) can be generated by linearly polarized light incident at the end of a nanowire, exciting a coherent superposition of three specific nanowire waveguide modes. Images of chiral SPPs on individual nanowires obtained from quantum dot fluorescence excited by the SPP evanescent field reveal the chirality predicted in our theoretical model. The handedness and spatial extent of the helical periods of the chiral SPPs depend on the input polarization angle and nanowire diameter as well as the dielectric environment. Chirality is preserved in the free-space output wave, making a metallic nanowire a broad bandwidth subwavelength source of circular polarized photons.

Correlation between incident and emission polarization in nanowire surface plasmon waveguides.

Nanowire plasmons can be launched by illumination at one terminus of the nanowire and emission can be detected at the other end of the wire. Using polarization dependent dark-field scattering spectroscopy, we measure how the polarization of the emitted light depends on the polarization of the incident light. We observe that the shape of the nanowire termination plays an important role in determining this polarization change. Depending on termination shape, a nanowire can serve as either a polarization-maintaining waveguide, or as a polarization-rotating, nanoscale half-wave plate. The understanding of how plasmonic waveguiding influence the polarization of the guided light is important for optimizing the structure of integrated plasmonic devices.

Bleach-imaged plasmon propagation (BlIPP) in single gold nanowires.

Here, we present a novel approach to visualize propagating surface plasmon polaritons through plasmon-exciton interactions between single gold nanowires and a thin film of a fluorescent polymer. A plasmon polariton was launched by exciting one end of a single gold nanowire with a 532 nm laser. The local near-field of the propagating plasmon modes caused bleaching of the polymer emission. The degree of photobleaching along the nanowire could be correlated with the propagation distance of the surface plasmon polaritons. Using this method of bleach-imaged plasmon propagation (BlIPP), we determined a plasmon propagation distance of 1.8 +/- 0.4 mum at 532 nm for chemically grown gold nanowires. Our results are supported by finite difference time domain electromagnetic simulations.

Fano-like interference in self-assembled plasmonic quadrumer clusters.

Assemblies of strongly interacting metallic nanoparticles are the basis for plasmonic nanostructure engineering. We demonstrate that clusters of four identical spherical particles self-assembled into a close-packed asymmetric quadrumer support strong Fano-like interference. This feature is highly sensitive to the polarization of the incident electric field due to orientation-dependent coupling between particles in the cluster. This structure demonstrates how careful design of self-assembled colloidal systems can lead to the creation of new plasmonic modes and the enabling of interference effects in plasmonic systems.

Effectiveness of Tolvaptan in the Treatment for Patients with Autosomal Dominant Polycystic Kidney Disease: A Meta-analysis.

AIMS AND OBJECTIVE: Autosomal Dominant Polycystic Kidney Disease (ADPKD) is a common chronic kidney disease that leads to End-Stage Renal Disease (ESRD). The key target of this therapy is to prevent the progression of kidney failure. Tolvaptan could slow kidney cyst growth and are proven highly effective. The aims of this analysis are to perform a systematic review, estimate and evaluate the efficacy and safety of tolvaptan in ADPKD patients. MATERIALS AND METHODS: Randomized controlled trials of tolvaptan in ADPKD were identified in PubMed, Ovid, Web of Science and the Cochrane Library electronic database. The changes observed in kidney function, treatment efficiency and the incidence of adverse events between the tolvaptan and placebo groups were compared. Data were analyzed by the RevMan software. RESULTS: Eight trials, including 7 double-blinded randomised controlled trials and 1 quasi RCT involving 1,536 patients were extracted. Significant differences in the annual rate of change in the total kidney volume TKV at any stages of CKD (MD = -3.32, 95%CI =-4.57,-2.07, I2 =70%) and the glomerular filtration rate (MD = 1.4, 95%CI = 0.83,1.97, I2 =0%) were observed between the tolvaptan group and the placebo group. Subgroup analysis of patients in different CKD stages also showed the same conclusion. There was an increase in the urine osmolality, and 24-hour urine volume in patients receiving tolvaptan. Tolvaptan reduced the rate of serious hypertension and kidney pain events in ADPKD patients. At higher doses, it increased the rate of adverse events (liver injuries, thirst, pollakiuria, and nocturia). There was no significant risk of bias in the included studies. CONCLUSION: Tolvaptan has a beneficial effect on ADPKD, but is associated with an increase in adverse events at high doses when compared with the placebo. Further RCTs on tolvaptan may be required to support this conclusion.

Fano resonances in plasmonic nanoparticle aggregates.

We investigate the plasmonic properties of a symmetric silver sphere septamer and show that the extinction spectrum exhibits a narrow Fano resonance. Using the plasmon hybridization approach and group theory we show that this Fano resonance is caused by the interference of two bonding dipolar subradiant and superradiant plasmon modes of E(1u) symmetry. We investigate the effect of structural symmetry breaking and show that the energy and shape of the Fano resonance can be tuned over a broad wavelength range. We show that the wavelength of the Fano resonance depends very sensitively on the dielectric permittivity of the surrounding media with one of the highest LSPR sensitivities reported for a finite nanostructure.

[Changes in serum endothelin and in pregnant rabbits with pulmonary embolism].

OBJECTIVE: To study change of serum endothelin (ET) and in serum endothelin and in pregnant rabbit with acute pulmonary embolism. METHODS: In 17 pregnant rabbits, autologous blood clots were administered into the right atrium via the femoral vein to establish the animal models of acute pulmonary embolism, and another 10 pregnant rabbits received injection with saline to serve as the control group. Serum levels of ET and CGRP were measured before, 0, 2, 4, 6 and 8 h after the injection. RESULTS: Acute pulmonary embolism was induced in all the rabbits receiving the injection of autologous blood clots with a success rate of 100%. In these rabbit models of pulmonary embolism, serum ET increased 0 h after the embolism and kept rising till 6 h, whereas CGRP level underwent immediate decrease after the embolism followed then by increase during the period from 4 to 8 h, showing significant difference from the levels of the control group. CONCLUSION: Significant difference in serum ET and CGRP levels occur in the event of acute pulmonary embolism in pregnant rabbits.

Geometric Dependence of the Line Width of Localized Surface Plasmon Resonances.

For the same number of electrons and plasmon frequencies, longitudinal plasmon resonances in metallic nanorods exhibit narrower line widths than plasmon modes in spherical particles. We show that this property is a general feature of high aspect ratio nanostructures and can be explained very simply by incorporating retardation effects into a harmonic oscillator model. The origin of the effect is dynamic depolarization, which renormalizes the mass of the electrons and the oscillating electron liquid. The scattering spectrum derived from our model agrees very well with FDTD simulations. Because plasmon damping determines many important features and applications of LSPR, such as the Q factor of plasmonics devices and the magnitude of the induced field enhancements, our study will play an important role for the design of nanostructures with narrow plasmon resonances.

Manipulating magnetic plasmon propagation in metallic nanocluster networks.

Neighboring fused heptamers can support magnetic plasmons due to the generation of antiphase ring currents in the metallic nanoclusters. In this paper, we use such artificial plasmonic molecules as basic elements to construct low-loss plasmonic waveguides and devices. These magnetic plasmon-based complexes exhibit waveguiding functionalities including plasmon steering over large-angle bends, splitting at intersections, and Mach-Zehnder interference between consecutive Y-splitters. Our findings provide a strategy for circumventing significant challenges in the miniaturization and high-density integration of optical circuits in integrated optics, allowing for the development of ultracompact plasmonic networks for practical applications.

Identification of higher order long-propagation-length surface plasmon polariton modes in chemically prepared gold nanowires.

A comprehensive understanding of the type of modes and their propagation length for surface plasmon polaritons (SPPs) in gold nanowires is essential for potential applications of these materials as nanoscale optical waveguides. We have studied chemically synthesized single gold nanowires by a novel technique called bleach-imaged plasmon propagation (BlIPP), which relies on the plasmonic near-field induced photobleaching of a dye to report the SPP propagation in nanowires. We observed a much longer propagation length of 7.5 ± 2.0 µm at 785 nm compared to earlier reports, which found propagation lengths of ~2.5 µm. Finite difference time domain simulations revealed that the bleach-imaged SPP is a higher order m = 1 mode and that the lowest order m = 0 mode is strongly quenched due to the loss to the dye layer and cannot be resolved by BlIPP. A comparative assessment of BlIPP with direct fluorescence imaging furthermore showed that the significant difference in propagation lengths obtained by these two techniques can be attributed to the difference in their experimental conditions, especially to the difference in thickness of the dye layer coating on the nanowire. In addition to identifying a higher order SPP mode with long propagation length, our study infers that caution must be taken in selecting indirect measurement techniques for probing SPP propagation in nanoscale metallic waveguides.

Self-assembled plasmonic nanoparticle clusters.

The self-assembly of colloids is an alternative to top-down processing that enables the fabrication of nanostructures. We show that self-assembled clusters of metal-dielectric spheres are the basis for nanophotonic structures. By tailoring the number and position of spheres in close-packed clusters, plasmon modes exhibiting strong magnetic and Fano-like resonances emerge. The use of identical spheres simplifies cluster assembly and facilitates the fabrication of highly symmetric structures. Dielectric spacers are used to tailor the interparticle spacing in these clusters to be approximately 2 nanometers. These types of chemically synthesized nanoparticle clusters can be generalized to other two- and three-dimensional structures and can serve as building blocks for new metamaterials.

Electron energy-loss spectroscopy (EELS) of surface plasmons in single silver nanoparticles and dimers: influence of beam damage and mapping of dark modes.

We demonstrate the use of a scanning transmission electron microscope (STEM) equipped with a monochromator and an electron energy loss (EEL) spectrometer as a powerful tool to study localized surface plasmons in metallic nanoparticles. We find that plasmon modes can be influenced by changes in nanostructure geometry and electron beam damage and show that it is possible to delineate the two effects through optimization of specimen preparation techniques and acquisition parameters. The results from the experimental mapping of bright and dark plasmon energies are in excellent agreement with the results from theoretical modeling.