Search

This paper explores the detection capability of space-borne detectors to the anisotropic stochastic gravitational-wave background (SGWB) without relying on the low-frequency approximation. To assess the detection performance, we calculate the power-law integrated sensitivity (PLIS) curve. Our results demonstrate that a single detector has limited capabilities in detecting multipole moments beyond the monopole ($l=0$), quadrupole ($l=2$), and hexadecapole ($l=4$). However, when multiple detectors are combined, the presence of multiple pointing directions and the separation between detectors significantly enhance the detection capabilities for the other multipole moments. For instance, when considering the dipole ($l=1$), combining TianQin with TianQin II and LISA with TianQin significantly improves the detection sensitivity by 2-3 orders of magnitude, compared with using a single TianQin and a single LISA, respectively., Comment: 12 pages, 8 figures

Raman spectroscopy is a powerful tool to detect, analyze and identify molecules. It has been a long-history pursuit to push the detection limit of Raman spectroscopy down to the fundamental single-molecule (SM) level. Due to the tiny cross section of intrinsic Raman scattering of molecule, some enhancement mechanisms of light-matter interaction must be implemented to levitate the Raman scattering intensity by a huge number of ~14-15 orders of magnitude, to the level comparable with the molecule fluorescence intensity. In this work we report unambiguous observation of single-molecule Raman spectroscopy via synergic action of electromagnetic and chemical enhancement for rhodamine B (RhB) molecule absorbed within the plasmonic nanogap formed by gold nanoparticle sitting on the two-dimensional (2D) monolayer WS2 and 2 nm SiO2 coated gold thin film. Raman spectroscopy down to an extremely dilute value of 10-18 mol/L can still be clearly visible, and the statistical enhancement factor could reach 16 orders of magnitude compared with the reference detection sample of silicon plate with a detection limit of 10-2 mol/L. The electromagnetic enhancement comes from local surface plasmon resonance induced at the nanogap, which could reach ~10-11 orders of magnitude, while the chemical enhancement comes from monolayer WS2 2D material, which could reach 4-5 orders of magnitudes. The synergic implementation and action of these two prestigious Raman scattering enhancement mechanisms in this specially designed 2D material-plasmon nanogap composite nanoscale system enables unambiguous experimental observation of single-molecule Raman spectroscopy of RhB molecule. This route of Raman enhancement devices could open up a new frontier of single molecule science, allowing detection, identification, and monitor of single molecules and their spatial-temporal evolution under various internal and external stimuli.

Objective: Our study aimed to investigate function and mechanism of miR-373 in proliferation and apoptosis of pancreatic cancer (PC) cells by regulating NAD+-dependent histone deacetylase sirtulin 1 (SIRT1). Materials and Methods: This experimental study included two PC cell lines AsPC-1 and PANC-1 in which expression levels of miR-373 and SIRT1 were manipulated. The level of miR-373 was detected by reverse transcription quantitative polymerase chain reaction (RT-qPCR) method. Expression levels of SIRT1, BCL-2, BAX, cleaved CASPASE-8/9/3, PARP, PGC-1α, NRF2, eNOS and iNOS were examined via RT-qPCR and western blotting, respectively. The binding sites of miR-373 on the SIRT1 were examined via dual-luciferase assay. Cell proliferation and apoptosis were examined by MTT assay, colony formation assay, Annexin-V/PI staining and TUNEL assay. The oxidative metabolic changes were monitored by reactive oxygen species (ROS), malondialdehyde (MDA) and superoxide dismutase (SOD) detection. Results: miR-373 could specifically target the 3’-UTR of SIRT1 and reduce its expression in PC cells. Either elevated expression of miR-373 or partial loss of SIRT1 inhibited cell proliferation and induced cell apoptosis. Accumulation of BAX and cleaved CASPASE-8/9/3, inhibition of PGC-1α/NRF2 pathway, increase oxidative stress and reduction of BCL-2 as well as uncleaved PARP were found in the presence of miR-373 or the absence of SIRT1. Overexpression of SIRT1 could reduce anti-proliferative and pro-apoptotic effects of miR-373. Conclusion: Overall, this study concluded that miR-373-dependent SIRT1 inhibition displays anti-proliferative and proapoptotic roles in PC cells via PGC-1α/NRF2 pathway, which highlights miR-373 as a potential target for PC treatment.

Metastasis is the main fatal cause of colorectal cancer (CRC). Although enormous efforts have been made to date to identify biomarkers associated with metastasis, there is still a huge gap to translate these efforts into effective clinical applications due to the poor consistency of biomarkers in dealing with the genetic heterogeneity of CRCs. In this study, a small cohort of eight CRC patients was recruited, from whom we collected cancer, paracancer, and normal tissues simultaneously and performed whole-exome sequencing. Given the exomes, a novel statistical parameter LIP was introduced to quantitatively measure the local invasion power for every somatic and germline mutation, whereby we affirmed that the innate germline mutations instead of somatic mutations might serve as the major driving force in promoting local invasion. Furthermore, via bioinformatic analyses of big data derived from the public zone, we identified ten potential driver variants that likely urged the local invasion of tumor cells into nearby tissue. Of them, six corresponding genes were new to CRC metastasis. In addition, a metastasis resister variant was also identified. Based on these eleven variants, we constructed a logistic regression model for rapid risk assessment of early metastasis, which was also deployed as an online server, AmetaRisk (http://www.bio-add.org/AmetaRisk). In summary, we made a valuable attempt in this study to exome-wide explore the genetic driving force to local invasion, which provides new insights into the mechanistic understanding of metastasis. Furthermore, the risk assessment model can assist in prioritizing therapeutic regimens in clinics and discovering new drug targets, and thus substantially increase the survival rate of CRC patients.

The recombination rate of markers far away from the candidate gene in the F2 and BC1P1 population. (DOCX 13 kb)

Supplementary 1. Sequences of W1827 and P1835. (DOC 29 kb)

Surface plasmon polaritons (SPPs) have been widely investigated in the past decades. Due to their unique feature of field localization, optical energy can be strongly confined in the subwavelength and even nanoscale space. This strong confinement gives rise to dramatically increased electromagnetic field strength, leading to greatly enhanced light-matter interactions. The properties of SPP are strongly dependent on material, morphology and structure. The wavelength of surface plasmon resonance can be readily manipulated over broadband optical spectra, covering ultraviolet, visible, near infrared to far infrared. In this review article, both working principle and applications of surface plasmon enhanced light-matter interactions, such as fluorescence, Raman scattering, nonlinear optics, heat effects, photoacoustic effects, photo-catalysis, and photovoltaic conversion, are comprehensively reviewed. Besides, the current problems and future research directions of surface plasmons are discussed. Our paper provides valuable reference for future high-performance plasmonic device and technology applications.

Many delayed-choice experiments based on Mach-Zehnder interferometers (MZI) have been thought and made to address the fundamental problem of wave-particle duality. Conventional wisdoms long hold that by inserting or removing the second beam splitter (BS2) in a controllable way, microscopic particles (photons, electrons, etc.) transporting within the MZI can lie in the quantum superposition of the wave and particle state as \psi=a_w\psi_wave+a_p\psi_particle. Here we present an alternative interpretation to these delayed-choice experiments. We notice that as all composite devices of MZI including BS2 are purely classical, the inserting and removing operation of BS2 imposes a time-modulated Hamiltonian H_mod(t)=a(t)H_in+b(t)H_out, instead of a quantum superposition of H_in and H_out as H=a_wH_in+b_pH_out, to act upon the incident wave function. Solution of this quantum scattering problem, rather than the long held quantum eigen-problem yields a synchronically time-modulated output wave function as \psi_mod=a(t)\psi_wave+b(t)\psi_particle. As a result, the probability of particle output from the MZI behaves as if they are in the superposition of the wave and particle state when many events over time accumulation are counted and averaged. We expect these elementary but insightful analyses will shed a new light on exploring basic physics beyond the long-held wisdom of wave-particle duality and principle of complementarity., Comment: 19 pages, 3 figures

High-quality three-dimensional polystyrene opal photonic crystals are fabricated by vertical deposition method. The transmission properties with different incident angles and different composite refractive index contrasts are experimentally and theoretically studied. Good agreement between the experiment and theory is achieved. We find that with the increasing incident angle, the gap position shifts to the short wavelength (blue shift) and the gap becomes shallower; and with the increase of refractive index of the opal void materials and decrease the contrast of refractive index, the gap position shifts to the long wavelength (red shift). At the same time, we observe the swelling effects when the sample is immerged in the solutions with different refractive indices, which make the microsphere diameter in solution become larger than that in air. The understanding of band gap shift behaviour may be helpful in designing optical sensors and tunable photonic crystal ultrafast optical switches.

We numerically investigate the quality factors of two-dimensional (2D) photonic crystal (PC) microcavities using an auxiliary differential equations (ADE) technique in the context of finite-difference time-domain (FDTD) method. The microcavities are formed by point defects in the air hole lattice hexagonally patterned in ZnO (zinc oxide) matrix. The quality factors of these microcavities are limited primarily by the absorption of the background dielectric. We show that the ratio between the quality factors of microcavities in lossy and lossless background dielectric depends on the overlap between the field of cavity modes and the absorbing background dielectric in addition to the magnitude of absorption. These results will be helpful when designing and optimizing photonic crystal microcavities formed in lossy medium.

We numerically investigate the coupling of TE-like modes and TM-like modes in a two-dimensional (2D) photonic crystal (PC) slab composed of truncated cone silicon rods. In such structures, the classification of TE-like modes and TM-like modes is generally impossible and the coupling occurs due to vertical structural asymmetries. The frequency and wavevector dependences of the mode coupling are discussed by investigating the photonic band structures, and the coupling efficiency is studied by examining the transmittance. The results show that the efficiency of mode conversion is strengthened by the vertical asymmetry and weakened by the clear small gap. These structures could be used as polarization conversion devices in integrated optics.

A highly efficient W3 Y-branch filter in a two-dimensional photonic crystal slab with triangular lattice of air holes is designed and fabricated, and its transmission properties are measured. By accurately adjusting the size of the resonant cavities, the minimum wavelength spacing of 7 nm between two channels is realized. The corresponding resonant wavelengths of the two cavities agree well with the calculated ones. This implies that this kind of filter may be promising in integrated wavelength division multiplexing system.

We report the imaging properties of a two-dimensional rectangular-lattice photonic crystal (PC) slab consisting of rectangular metallic rods immersed in a dielectric background. By simulating the electromagnetic wave propagation through such a PC slab with the finite-difference time-domain method, we find that a point source placed in the vicinity of the PC slab can form a good-quality image through the slab. The frequency region where a good-quality image is formed can be controlled by choosing the direction along which the PC slab surface normal is placed.

We demonstrate a high-performance apertureless near-field probe made of a tapered metal tip with a set of periodic shallow grooves near the apex. The spontaneous emission from a single emitter near the tip is investigated systematically for the side-illumination tip enhanced spectroscopy (TES). In contrast with the bare tapered metal tip in conventional side-illumination TES, the corrugated probe not only enhances strongly local excitation field but also concentrates the emission directivity, which leads to high collection efficiency and signal-to-noise ratio. In particular, we propose an asymmetric TES tip based on two coupling nanorods with different length at the apex to realize unidirectional enhanced emission rate from a single emitter. Interestingly, we find that the radiation pattern is sensitive to the emission wavelength and the emitter positions respective to the apex, which can result in an increase of signal-to-noise ratio by suppressing undesired signal. The proposed asymmetrical corrugated probe opens up a broad range of practical applications, e.g. increasing the detection efficiency of tip enhanced spectroscopy at the single-molecule level.

The extraordinary light transmission through a 200-nm thick gold film when passing through different subwavelength hole arrays is observed experimentally. The sample is fabricated by electron beam lithography and reactive ion etching system. A comparison between light transmissions shows that the hole shape changing from rectangular to diamond strongly affects the transmission intensity although both structures possess the same lattice constant of 600 nm. Moreover, the position of the transmission maximum undergoes a spectral red-shift of about 63 nm. Numerical simulations by using a transfer matrix method reproduce the observed transmission spectrum quite well.

Imaging properties of a two-dimensional photonic crystal (PC) slab consisting of a triangular lattice of metallic cylinders immersed in a dielectric background are investigated by the finite-difference time-domain technique. With the calculated field patterns of a point source placed in the vicinity of the PC slab and the corresponding equifrequency-surface contours, we find that a high-quality image can form in the opposite side of the slab in the lowest TM-polarized photonic band, and this near-field image is formed mainly by the self-collimation effect.

Scalar diffraction theory, although simple and efficient, is too rough for analysing diffractive micro-optical elements. Rigorous vectorial diffraction theory requires extensive numerical efforts and is not a convenient design tool. In this paper we employ a simple approximate vectorial diffraction model which combines the principle of the scalar diffraction theory with an approximate local field model to analyse the diffraction of optical waves by some typical two-dimensional diffractive micro-optical elements. The TE and TM polarization modes are both considered. We have found that the approximate vectorial diffraction model can agree much better with the rigorous electromagnetic simulation results than the scalar diffraction theory for these micro-optical elements.

Defect modes in one-dimensional photonic crystals (PCs) can be readily detected from the solution of the transmission spectra via the standard transfer-matrix method. We adopt an analytic Bloch-mode approach to examine this problem in terms of eigenmode solutions and investigate the dispersion behaviour of localized defect modes supported by a defect layer sandwiched within two symmetric semi-infinite PCs that are made from multiple constituents. The results show that the number of defect modes grows when the dielectric constant and width of the defect layer increase.

Silicon photonics is considered as a promising technology to realize high-performance photonic integrated circuits, owing to its complementary metal oxide semiconductor-compatibility which is applicable for large-scale integration at low cost. However, due to the limitation of optoelectronic properties of silicon, the challenge to the realization of high-performance active device on the silicon integrated platform still exists. The recent development of graphene-silicon hybrid photonic integrated circuit provides a practical solution to this problem, because graphene, as a superior two-dimensional material, possesses many advantageous optoelectronic properties, such as high mobility, high electro-optical coefficient, and broadband absorption, which can be fully exploited to break through the material limitation of silicon. Moreover, compared with other active integrated materials such as germanium and compound semiconductors, graphene is cost-effective and can be conveniently integrated with silicon photonic device. Here, we review some important research progress of graphene-silicon hybrid photonic integrated circuits that include optical sources, optical waveguides, optical modulators, and photodetectors. The challenges and prospects of these devices are also analyzed, which are expected to be beneficial to the relevant research communities.

We have investigated second harmonic generation (SHG) from Ag-coated LiNbO3 (LN) core-shell nanocuboids and found that giant SHG can occur via deliberately designed double plasmonic resonances. By controlling the aspect ratio, we can tune fundamental wave (FW) and SHG signal to match the longitudinal and transverse plasmonic modes simultaneously, and achieve giant enhancement of SHG by more than five orders of magnitude in comparison to a bare LN nanocuboid and by about one order of magnitude to the case adopting only single plasmonic resonance. The underlying key physics is that the double-resonance nanoparticle enables greatly enhanced trapping and harvesting of incident FW energy, efficient internal transfer of optical energy from FW to SHW, and much improved power to transport the SHG energy from the nanoparticle to the far-field region. The proposed double-resonance nanostructure can serve as an efficient subwavelength coherent light source through SHG and enable flexible engineering of light-matter interaction at nanoscale.

Negative refraction and imaging properties of the electromagnetic wave through a two-dimensional photonic crystal (PC) slab, which consists of a square lattice of elliptical dielectric rods immersed in the air background, is studied by the plane-wave expansion method and the finite-difference time-domain method. A point source placed in the vicinity of the PC slab can form a good-quality image spot through the PC slab for the incident frequencies within the second photonic band. The calculated result also shows that negative refraction occurs in this kind of PC slab.

Two kinds of subwavelength hole arrays in metallic films are designed to verify the important role of the periodicity in enhanced transmission of light. The measured optical spectra show that the quasiperiodic hole arrays exhibit an enhanced transmission peak centred at 707 nm with a transmission intensity of about 20%, while no plasmon resonance peak is found for the amorphous hole arrays. When the hole diameter decreases in the quasiperiodic structure, the position of the transmission peak shifts slightly, and the transmittance drops. These phenomena indicate the important role of the long-range structural order (particularly the periodicity) in assisting the coupling of incident light wave with the surface plasmon modes of the metallic structures.

We fabricated two-dimensional photonic crystal slab Y-branch waveguides with different intervals between the two output ports and measured their light guiding characteristics. The field intensity distributions of the TE polarized wave modes are also calculated by means of a transfer matrix method. Both the theoretical and experimental results show that the minimum interval between the two output ports is about 1.4 times the transport wavelength of 1.55 μm. If the interval becomes smaller, light waves in the two branches will couple each other seriously. The result will be helpful for designs of ultracompact wave demultiplexers and all-optical integrated circuits.

The transmission properties of quasiperiodic photonic crystals (QPCs) based on the random square-triangle tiling system are investigated by the multiple scattering method. The hollow cylinders are introduced in our calculation. It is found that QPCs with hollow cylinders also possess a complete band gap common to s- and p-polarized waves when the inner radius of hollow cylinders is larger than a certain value. The QPCs possessing the complete band gap can be applied to the fields of light emitting, wave-guides, optical filters, high-Q resonators and antennas.

On-chip optical isolators play a key role in optical communications and computing based on silicon integrated photonic structures. Recently there have raised great attentions and hot controversies upon isolation of light via linear and passive photonic structures. Here we analyze the optical isolation properties of a silicon photonic crystal slab heterojunction diode by comparing the forward transmissivity and round-trip reflectivity of in-plane infrared light across the structure. The round-trip reflectivity is much smaller than the forward transmissivity, justifying good isolation. The considerable effective nonreciprocal transport of in-plane signal light in the linear and passive silicon optical diode is attributed to the information dissipation and selective modal conversion in the multiple-channel structure and has no conflict with reciprocal principle., Comment: 14 pages, 4 figures

All-optical integrated circuits for computing and information processing have been pursued for decades as a potential strategy to overcome the speed limitations intrinsic to electronics. However feasible on-chip integrated logic units and devices still have been limited by its size, quality, scalability, and reliability. Here we demonstrate all-passive on-chip optical AND and NAND logic gates made from a directional emitting cavity connecting two ultrasmall photonic crystal heterojunction diodes. The measured transmission spectra show more than 10dB contrast of the logic transport with a high phase tolerance, agreeing well with numerical simulations. The building of linear, passive, and ultracompact silicon optical logic gates might pave the way to construct novel nanophotonic on-chip processor architectures for future optical computing technologies., Comment: 19 pages, 5 figures

Based on the concept of quasi-phase matching nonlinear interaction, and successful fabrication of nonlinear photonic crystal using high voltage electric field in 90's, studies on nonlinear photonic crystal were made by different research teams. The related works sharply developed from single one-dimensional superlattice to various structures. On the other hand, further fabrications were made in these crystals, for example, the fabrication of optical waveguides etc. Fabrications of multiple optical waveguides in one two-dimensional photonic crystal were suggested in this paper. This will be helpful to the extension of laser wavelengths, compact optical elements and all-optical switches.

Complementarity lies at the heart of conceptual foundation of orthodox quantum mechanics. The wave-particle duality makes it impossible to tell which slit each particle passes through and still observe an interference pattern in a Young's double-slit experiment. In this paper, this duality is appraised under the standard formulation of quantum mechanics for atom interferometers. It is found that the internal freedoms like electronic states of an atom can be used to detect the which-path information of each atom while uphold the interference pattern of atoms when the center-of-mass motion of atoms is detected., 4 pages in revtex format, no figures

A local realistic model for quantum mechanics of two-particle Einstein-Podolsky-Rosen pairs is proposed. In this model, it is the strict obedience of conservation laws in each event at the quantum level that uphold the perfect correlation of two spatially-separated particles, instead of nonlocality in the orthodox formulation of quantum mechanics. Therefore, one can conclude that all components of the spin of two particles, and the position and momentum of a particle can be measured simultaneously. The proposed model yields the same statistical prediction on an ensemble of individual particles as the orthodox formulation does. This suggests that the wave function is not a complete description of individual particle as assumed in the orthodox formulation, but only a statistical description of an ensemble of particles., 4 pages, prepared in REVTEX format; 1 postscript figure

A material with the formula ZrMgMo3O12 having negative thermal expansion is presented and characterized. It is shown that ZrMgMo3O12 crystallizes in an orthorhombic symmetry with space group Pnma(62) or Pna21(33) and exhibits negative thermal expansion in a large temperature range (αl = −3.8 × 10−6 K−1 from 300K to 1000K by x-ray diffraction and αl = −3.73 × 10−6 K−1 from 295K to 775K by dilatometer). ZrMgMo3O12 remains the orthorhombic structure without phase transition or decomposition at least from 123K to 1200K and is not hygroscopic. These properties make it an excellent material with negative thermal expansion for a variety of applications.

We present a systematic experimental investigation on visible light collimation by a nanostructured slit flanked with a pair of periodic array of grooves in gold thin film. A wide variety of aspects are considered, such as the polarization state, the transport path of incident light, the groove—groove spacing, the groove width and depth. Our results clearly show that the relationship between the collimation wavelength and the periodicity of the slit-groove structure accords well with the surface plasmon dispersion model proposed by previous researchers. Furthermore, the surface plasmon wave phase retardation effect induced by the surface structure is also verified via the measurement for samples with different groove widths and depths. These results indicate that the detailed geometry of the groove structure has obvious impacts on the collimation effect and the angular distribution of the diffraction light in the subwavelength plasmonic system.

Second harmonic generation (SHG) in one-dimensional nonlinear photonic crystals made from periodically alternating ferroelectric and dielectric layers is investigated by means of the transfer matrix method. When tuned at the photonic band gap (PBG) edges, the fundamental wave and second harmonic wave slow down, and the filed enhancement takes place within the nonlinear photonic crystal. The phase mismatching can be compensated for to some extent and the second harmonic process will be enhanced. Numerical results show that the enhancement of SHG in the PBG structure can be up to four orders of magnitude compared with the traditional quasi-phase-matching structure.

We design and realize a 90° waveguide bend in two-dimensional triangular lattice silicon photonic crystal slabs by connecting linear waveguides along the orthogonal Γ – K and Γ – M directions. A pass band of 70 nm is realized by optimizing the geometry of the Γ – M waveguide. The connection region of the waveguide bend is optimized to improve the transmission efficiency of infrared light through the two different kinds of waveguides. The transmission efficiency of an optimized single bend is about 75% in simulation and 45% in measurement.

We design high quality factor (Q) photonic crystal microcavities in diamond films for applications in quantum information based on color centers. A photonic microcavity made from a waveguide heterostructure with a mode gap is demonstrated to have a high Q factor over 1051400 and a modal volume V of 2.24 cubic wavelengths by modifying the mode gap width and the tapered region geometry. Besides its ultrahigh Q factor, the waveguide-like geometry of the cavity allows for easy on-chip transportation of quantum information between different cavities.

The translational symmetric associated with photonic crystal is absent in the rotationally symmetric quasiperiodic photonic crystal （QPCs）, and the quasiperiodic photonic crystal has more defect modes than photonic crystal because of it. In this paper, we investigate the defect modes in the 12-fold quasiperiodic photonic crystal by the multiple scattering method. We find that there is a directional defect mode in quasiperiodic photonic crystal. When the defect rotates against the centre of the symmetry, there emerges a new defect mode.

Using focused ion beam lithograph, we fabricated W3 straight waveguide in two-dimensional photonic crystal slab on SOI (silicon on insulator) wafer. The light propagation was observed on top and from the end of the sample. The transmission dip and mode distribution at the outlet of ridged waveguide were measured. The results show that light can propagate in the photonic crystal waveguide.

Photoluminescence (PL) spectra of annealed a-SixC1-x:H films were studied. The-widths of the exponential bandtails were determined by means of the temperature dependences of PL peak energy positions. The experimental results shows that PL peak energy positions shift towards the lower energy with annealing temperature increasing. The bandtail widths have been calculated according to the exponential bandtail model, the calculation shows that the bandtails contract with increase of annealing temperature. A discussion about the results has been given.

Background: Neuropathic pain evoked by nerve injury is frequently accompanied by deterioration of emotional behaviors, but the underlying signaling mechanisms remain elusive. Glutamate (Glu) is the major mediator of excitatory synaptic transmission throughout the brain, and abnormal activity of the glutamatergic system has been implicated in the pathophysiology of pain and associated emotional comorbidities. In this study we used the partial sciatic nerve ligation (PSNL) model of neuropathic pain in rats to characterize the development of anxiety-like behavior, the expression of glutamatergic receptors, and the phosphorylation of extracellular signal-regulated kinase (ERK) in the hippocampus, the region that encodes memories related to emotions. Results: We found that the mechanical withdrawal threshold was significantly reduced and an anxiety-like behavior was increased as determined via open field tests and elevated plus-maze tests at 28 days after injury. No significant differences were found in the ratio of sucrose preference and immobility time detected by sucrose preference tests and forced swimming tests respectively, possibly due to the timing factor. The expression of N-methyl-D-aspartate (NMDA) receptor subtypes NR1 and NR2B, but not NR2A, GluR1, or GluR2 (the main subtype of the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid [AMPA] receptor) in the hippocampus of injured rats was significantly reduced. Moreover, PSNL resulted in decreased phosphorylation of ERK1/2 in the hippocampus. Intriguingly, treatment with D-serine (a co-agonist of NMDA receptor, 1 g/kg intraperitoneally) reduced the anxiety-like behavior but not the mechanical hypersensitivity induced by PSNL. Conclusions: PSNL can induce significant anxiety-like but not depression-like behavior, and trigger down-regulation of NMDA but not AMPA receptors in the hippocampus at 28 days after injury. Refereed/Peer-reviewed

In metal-enhanced fluorescence (MEF), the localized surface plasmon resonances of metallic nanostructures amplify the absorption of excitation light and assist in radiating the consequent fluorescence of nearby molecules to the far-field. This effect is at the base of various technologies that have strong impact on fields such as optics, medical diagnostics and biotechnology. Among possible emission bands, those in the near-infrared (NIR) are particularly intriguing and widely used in proteomics and genomics due to its noninvasive character for biomolecules, living cells, and tissues, which greatly motivates the development of effective, and eventually multifunctional NIR-MEF platforms. Here we demonstrate NIR-MEF substrates based on Au nanocages micropatterned with a tight spatial control. The dependence of the fluorescence enhancement on the distance between the nanocage and the radiating dipoles is investigated experimentally and modeled by taking into account the local electric field enhancement and the modified radiation and absorption rates of the emitting molecules. At a distance around 80 nm, a maximum enhancement up to 2-7 times with respect to the emission from pristine dyes (in the region 660 nm-740 nm) is estimated for films and electrospun nanofibers. Due to their chemical stability, finely tunable plasmon resonances, and large light absorption cross sections, Au nanocages are ideal NIR-MEF agents. When these properties are integrated with the hollow interior and controllable surface porosity, it is feasible to develop a nanoscale system for targeted drug delivery with the diagnostic information encoded in the fluorophore., Comment: 41 pages, 18 figures