Nobiletin protects retinal ganglion cells in models of ocular hypertension in vivo and hypoxia in vitro.

Glaucoma, a common cause of blindness, is characterized by the progressive loss of retinal ganglion cells (RGCs). Growing evidence suggests that nobiletin (NOB) is a promising neuroprotective drug; however, its effects on glaucomatous neurodegeneration remain unknown. Using rat models of microbead occlusion in vivo and primary RGCs model of hypoxia in vitro, we first demonstrate that NOB reduces RGC apoptosis by a TUNEL assay, Hoechst 33342 staining and FluoroGold (FG) retrograde labeling. This effect does not depend on intraocular pressure (IOP) lowering. Additionally, NOB partially restored the functional and structural damage of inner retinas, attenuated Müller glial activation and oxidative stress caused by ocular hypertension. At 2 weeks after IOP elevation, NOB further enhanced Nrf2/HO-1 pathway in RGCs to withstand the cumulative damage of ocular hypertension. With the administration of HO-1 inhibitor tin-protoporphyrin IX (SnPP), the protective effect of NOB was attenuated. Overall, these results indicate that NOB exerts an outstanding neuroprotective effect on RGCs of glaucomatous neurodegeneration. Besides, interventions to enhance activation of Nrf2/HO-1 pathway can slow the loss of RGCs and are viable therapies for glaucoma.

Quasi-phase-matched second harmonic generation of long-range surface plasmon polaritons.

In this paper, we experimentally demonstrate the second harmonic generation of long-range surface plasmon polaritons via quasi-phase matching in lithium niobate. After depositing a 9/13 nm thick Au film on periodically poled lithium niobate, TiO2 of about 2.3 µm in thickness is evaporated on the sample as a refractive-index-matching material. This dielectric (periodically poled lithium niobate)-metal(Au)-dielectric(TiO2) sandwich structure can support the transmission of long-range surface plasmon polaritons through it. By designing a moderate ferroelectric domain period of periodically poled lithium niobate, the phase mismatch between the fundamental wave and second harmonic wave of the long-range surface plasmon polaritons can be compensated and a second harmonic wave can be generated effectively. This can be used to provide integrated plasmonic devices with attractive applications in quantum and classic information processing.

Comparative transcriptome analysis reveals differentially expressed genes associated with sex expression in garden asparagus (Asparagus officinalis).

BACKGROUND: Garden asparagus (Asparagus officinalis) is a highly valuable vegetable crop of commercial and nutritional interest. It is also commonly used to investigate the mechanisms of sex determination and differentiation in plants. However, the sex expression mechanisms in asparagus remain poorly understood. RESULTS: De novo transcriptome sequencing via Illumina paired-end sequencing revealed more than 26 billion bases of high-quality sequence data from male and female asparagus flower buds. A total of 72,626 unigenes with an average length of 979 bp were assembled. In comparative transcriptome analysis, 4876 differentially expressed genes (DEGs) were identified in the possible sex-determining stage of female and male/supermale flower buds. Of these DEGs, 433, including 285 male/supermale-biased and 149 female-biased genes, were annotated as flower related. Of the male/supermale-biased flower-related genes, 102 were probably involved in anther development. In addition, 43 DEGs implicated in hormone response and biosynthesis putatively associated with sex expression and reproduction were discovered. Moreover, 128 transcription factor (TF)-related genes belonging to various families were found to be differentially expressed, and this finding implied the essential roles of TF in sex determination or differentiation in asparagus. Correlation analysis indicated that miRNA-DEG pairs were also implicated in asparagus sexual development. CONCLUSIONS: Our study identified a large number of DEGs involved in the sex expression and reproduction of asparagus, including known genes participating in plant reproduction, plant hormone signaling, TF encoding, and genes with unclear functions. We also found that miRNAs might be involved in the sex differentiation process. Our study could provide a valuable basis for further investigations on the regulatory networks of sex determination and differentiation in asparagus and facilitate further genetic and genomic studies on this dioecious species.

Polarization-independent broadband plasmonic absorber based on a silicon-nanowire array decorated by gold nanoparticles at the optical regime.

We present a design for a plasmonic absorber that is composed of a hexagonal-packed silicon nanowires (SiNWs) array with gold nanoparticles (AuNPs) decoration. Simulations and experiments demonstrated that the proposed absorber achieves a broadband absorption. Its bandwidth over an absorption of 80% ranges from 400 nm to 1000 nm at 0 degree to 30 degrees incidence. It was also demonstrated that the plasmonic absorber is polarization-insensitive. Analyzing the field distributions in the structure, we find that the wideband absorption is ascribed to the formation of cavity modes in the SiNWs and surface plasmon polaritons on the AuNPs. Such a designed plasmonic structure with high-efficiency absorption can be served as a good optical absorber.

Genes encoding Δ(8)-sphingolipid desaturase from various plants: identification, biochemical functions, and evolution.

∆(8)-sphingolipid desaturase catalyzes the C8 desaturation of a long chain base, which is the characteristic structure of various complex sphingolipids. The genes of 20 ∆(8)-sphingolipid desaturases from 12 plants were identified and functionally detected by using Saccharomyces cerevisiae system to elucidate the relationship between the biochemical function and evolution of this enzyme. Results showed that the 20 genes all can encode a functional ∆(8)-sphingolipid desaturase, which catalyzes different ratios of two products, namely, 8(Z) and 8(E)-C18-phytosphingenine. The coded enzymes could be divided into two groups on the basis of biochemical functions: ∆(8)-sphingolipid desaturase with a preference for an E-isomer product and ∆(8)-sphingolipid desaturase with a preference for a Z-isomer product. The conversion rate of the latter was generally lower than that of the former. Phylogenetic analysis revealed that the 20 desaturases could also be clustered into two groups, and this grouping is consistent with that of the biochemical functions. Thus, the biochemical function of ∆(8)-sphingolipid desaturase is correlated with its evolution. The two groups of ∆(8)-sphingolipid desaturases could arise from distinct ancestors in higher plants. However, they might have initially evolved from ∆(8)-sphingolipid desaturases in lower organisms, such as yeasts, which can produce E-isomer products only. Furthermore, almost all of the transgenic yeasts harboring ∆(8)-sphingolipid desaturase genes exhibit an improvement in aluminum tolerance. Our study provided new insights into the biochemical function and evolution of ∆(8)-sphingolipid desaturases in plants.

Amplified spontaneous emission via the coupling between Fabry-Perot cavity and surface plasmon polariton modes.

We demonstrated amplified spontaneous emission by embedding dye molecules within a dielectric layer of a metal-dielectric-metal subwavelength structure. It was reinforced when a strong coupling occurred between the Fabry-Perot mode supported by the dielectric layer and the surface plasmon polariton mode supported by the adjacent metallic grating. Here, we adjust the two mode interaction via tuning the depth of the metallic grating grooves. The stronger the interaction, the smaller the full width at half-maximum of the emission spectra and the lower the threshold of the amplified spontaneous emission.

Ordered Ag/Si nanowires array: wide-range surface-enhanced Raman spectroscopy for reproducible biomolecule detection.

Surface-enhanced Raman scattering (SERS) systems utilizing the interparticle nanogaps as hot spots have demonstrated ultrasensitive single-molecule detection with excellent selectivity yet the electric fields are too confined in the small nanogaps to enable reproducible biomolecule detections. Here, guided by finite-difference-time-domain simulation, we report hexagonal-packed silver-coated silicon nanowire (Ag/SiNW) arrays as a nanogap-free SERS system with wide-range electric fields and controlled interwire separation. Significantly, the system achieves a SERS detection of long double-strand DNA of 25-50 nm in length with a relative standard deviation (RSD) of 14% for measurements of above 4000 spots over an area of 200 × 200 µm(2). The high reproducibility in the SERS detection is attributed to (1) the large interwire spacing of 150 nm that allows access and excitation of large biomolecules; and (2) 600 nm wide-range electric field generated by propagating surface plasmons along the surface of continuous Ag coating on a SiNW. Moreover, a reproducible multiplex SERS measurement is also demonstrated with RSDs of 7-16% with an enhancement factor of ~10(6). The above results show that the ordered Ag/SiNW array system may serve as an excellent SERS platform for practical chemical and biological detection.

Surface-enhanced fluorescence of a dye-doped polymer layer with plasmonic band edge tuning.

We investigated experimentally the influence of 1D rectangular Au gratings on fluorescence. The formation of a bandgap in the dispersion relation is confirmed by our experiment. At the edge of this bandgap, the fluorescence of the dye can be strongly enhanced due to the surface plasmon polaritons' large density of states. By structural design we tuned the plasmonic band edges to the wavelength of the fluorescence of the dye molecules. An optimized Au grating structure with a duty ratio of 3/4 is found to achieve up to 120 times stronger fluorescence than that of a planar metal surface.

[CCR1 expression on immune cells in orbital tissue of patients with thyroid associated ophthalmopathy].

OBJECTIVE: To investigate the expression of CC chemokine receptor 1(CCR1) on the immune cells in orbital tissue of patients with thyroid associated ophthalmopathy(TAO). METHODS: The tissue samples of orbital tissue were collected from 25 cases of TAO patient and 10 normal control subjects, and the expression of CCR1 in the immune cells was studied by SP immunohistochemistry. The correlation between CCR1 and clinical activity scores (GAS) was analyzed. RESULTS: The expression of CCR1 on immune cells was positive, in orbital tissue of patients with TAO, and the positive rate was 84%, while it was negative or low positive in normal control subjects. The difference between them was significant (P < 0.05). In addition, the expression of CCR1 on the immune cells of orbital tissue with TAO had significant correlation with CAS (P < 0.05). CONCLUSION: The expression of chemokine receptor CCR1 on the immune cells in orbital tissue of TAO patients is higher than that of normal subjects. CCR1 may play a role in the pathogenesis of TAO.

[Expression of CCR1 in the orbital fibroblasts with thyroid associated ophthalmopathy].

OBJECTIVE: To investigate the expression of chemokine receptor (CCR1) in the orbital fibroblasts (OFs) with thyroid associated ophthalmopathy (TAO) and to explore the pathogenesis of TAO. METHODS: By immunohistochemistry, the expression of CCR1 was studied in 25 cases of TAO patients and 10 normal control subjects and the correlation between CCR1 and GAS was analysed. RESULTS: The expression of CCR1 in the OFs with TAO was positive, but it was negative or weak positive in normal control subjects. The difference between them was significant (P < 0.05). And the expression of CCR1 in the OFs with TAO had no significant correlation with GAS (r = 0. 048, P > 0.05). CONCLUSION: The expression of chemokine receptor CCR1 is higher on OFs of TAO patients than that of normal subjects. CCR1 maybe play a role in pathogenesis of TAO.

Electrical and photoresponse properties of an intramolecular p-n homojunction in single phosphorus-doped ZnO nanowires.

The single-crystal n-type and p-type ZnO nanowires (NWs) were synthesized via a chemical vapor deposition method, where phosphorus pentoxide was used as the dopant source. The electrical and photoluminescence studies reveal that phosphorus-doped ZnO NWs (ZnO:P NWs) can be changed from n-type to p-type with increasing P concentration. Furthermore, we report for the first time the formation of an intramolecular p-n homojunction in a single ZnO:P NW. The p-n junction diode has a high on/off current ratio of 2.5 x 10(3) and a low forward turn-on voltage of approximately 1.37 V. Finally, the photoresponse properties of the diode were investigated under UV (325 nm) excitation in air at room temperature. The high photocurrent/dark current ratio (3.2 x 10(4)) reveals that the diode has a potential as extreme sensitive UV photodetectors.

Tunable and enhanced light emission in hybrid WS2-optical-fiber-nanowire structures.

In recent years, the two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted renewed interest owing to their remarkable physical and chemical properties. Similar to that of graphene, the atomic thickness of TMDCs significantly limits their optoelectronic applications. In this study, we report a hybrid WS2-optical-fiber-nanowire (WOFN) structure for broadband enhancement of the light-matter interactions, i.e., light absorption, photoluminescence (PL) and second-harmonic generation (SHG), through evanescent field coupling. The interactions between the anisotropic light field of an optical fiber nanowire (OFN) and the anisotropic second-order susceptibility tensor of WS2 are systematically studied theoretically and experimentally. In particular, an efficient SHG in the WOFN appears to be 20 times larger than that in the same OFN before the WS2 integration under the same conditions. Moreover, we show that strain can efficiently manipulate the PL and SHG in the WOFN owing to the large configurability of the silica OFN. Our results demonstrate the potential applications of waveguide-coupled TMDCs structures for tunable high-performance photonic devices.

Total Saponins of Rubus Parvifolius L. Exhibited Anti-Leukemia Effect in vivo through STAT3 and eIF4E Signaling Pathways.

OBJECTIVE: To investigate the anti-leukemia effect of total saponins of Rubus parvifolius L. (TSRP) on K562 cell xenografts in nude mice and the mechanisms of action. METHODS: The K562 cell xenografts in nude mice were established, and then randomly divided into 5 groups, the control group, the cytosine arabinoside group(Ara-c) and 3 TSRP groups (20, 40 and 100 mg/kg). The tumor volume and mass of each group of nude mice were measured and the anti-tumor rates of TSRP were calculated subsequently. The apoptosis status of tumor cells was detected by hematoxylin-eosin (HE) and terminal dexynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) staining analysis. Finally, the activities of apoptosis related signaling of signal transducer and activator of transcription 3 (STAT3), eukaryotic initiation factor 4E (eIF4E) and B-cell lymphoma-2 (bcl-2) were determined with immunohistochemistry tests. RESULTS: Subcutaneous injection of K562 cells induced tumor formation in nude mice, and the TSRP treated group showed a signifificant inhibitory effect on tumor formation. The nude mice treated with TSRP showed a signifificant decrease in tumor growth rate and tumor weight in comparison to the control group (all P<0.05). The HE staining and TUNEL assay showed that TSRP induced cell death by apoptosis. The immunohistochemical assay showed down-regulation of the bcl-2 gene in the TSRP treated cells. The phosphorylation levels of eIF4E and STAT3 were decreased obviously after the treatment of TSRP. CONCLUSION: TSRP had an excellent tumor-suppressing effect on K562 cells in the nude mice xenograft model, suggesting that TSPR can be developed as a promising anti-chronic myeloide leukemia drug.

Salvage tigecycline in high risk febrile neutropenic patients with hematological malignancies: a prospective multicenter study.

The purpose of this prospective, multi-center study was to examine the efficacy and safety of tigecycline as empirical treatment in neutropenic patients with hematological malignancies who failed to respond to first-line antibiotics. A total of 125 patients with persistent fever (>72 h) despite first-line antibiotics received empirical treatment with tigecycline (loading dose of 100 mg, followed by 50 mg every 12 h). The use of other antimicrobial agents was not restricted. Treatment success rate was 68.0%. Subgroup analysis revealed a success rate of 73.1% in patients with pneumonia and 35.3% in patients with bacteremia. Toxicities were moderate with gastrointestinal symptoms being the main side effects. In conclusion, tigecycline-based antibacterial regimen was a justifiable empirical treatment in febrile neutropenic patients who failed to respond to first-line antibiotics except those with bacteremia. For patients with bacteremia, trials on higher-dose of tigecycline are needed.

TiOxNy Modified TiO2 Powders Prepared by Plasma Enhanced Atomic Layer Deposition for Highly Visible Light Photocatalysis.

In this work, TiN film deposited by plasma enhanced atomic layer deposition (PEALD) is adopted to modify the commercial anatase TiO2 powders. A series of analyses indicate that the surface modification of 20, 50 and 100 cycles of TiN by PEALD does not change the morphology, crystal size, lattice parameters, and surface area of TiO2 nano powders, but forms an ultrathin amorphous layer of nitrogen doped TiO2 (TiOxNy) on the powder surfaces. This ultrathin TiOxNy can facilitate the absorption of TiO2 in visible light spectrum. As a result, TiOxNy coated TiO2 powders exhibit excellent photocatalytic degradation towards methyl orange under the visible light with good photocatalytic stability compared to pristine TiO2 powders. TiOxNy (100 cycles PEALD TiN) coated TiO2 powders exhibit the excellent photocatalytic activity with the degradation efficiency of 96.5% in 2 hours, much higher than that of pristine TiO2 powder of only 4.4%. These results clearly demonstrate that only an ultrathin surface modification layer can dramatically improve the visible light photocatalytic activity of commercial TiO2 powders. Therefore, this surface modification using ALD is an extremely promising route to prepare visible light active photocatalysts.

Atomic-Layer-Deposition Assisted Formation of Wafer-Scale Double-Layer Metal Nanoparticles with Tunable Nanogap for Surface-Enhanced Raman Scattering.

A simple high-throughput approach is presented in this work to fabricate the Au nanoparticles (NPs)/nanogap/Au NPs structure for surface enhanced Raman scattering (SERS). This plasmonic nanostructure can be prepared feasibly by the combination of rapid thermal annealing (RTA), atomic layer deposition (ALD) and chemical etching process. The nanogap size between Au NPs can be easily and precisely tuned to nanometer scale by adjusting the thickness of sacrificial ALD Al2O3 layer. Finite-difference time-domain (FDTD) simulation data indicate that most of enhanced field locates at Au NPs nanogap area. Moreover, Au NPs/nanogap/Au NPs structure with smaller gap exhibits the larger electromagnetic field. Experimental results agree well with FDTD simulation data, the plasmonic structure with smaller nanogap size has a stronger Raman intensity. There is highly strong plasmonic coupling in the Au nanogap, so that a great SERS effect is obtained when detecting methylene blue (MB) molecules with an enhancement factor (EF) over 107. Furthermore, this plasmonic nanostructure can be designed on large area with high density and high intensity hot spots. This strategy of producing nanoscale metal gap on large area has significant implications for ultrasensitive Raman detection and practical SERS application.

Towards an all-in fiber photodetector by directly bonding few-layer molybdenum disulfide to a fiber facet.

Although photodetectors based on two dimensional (2D) materials have been intensively studied, there are few reports of optical fiber compatible devices. Herein we successfully fabricated an all-in fiber photodetector (FPD) based on an end-face bonded with few-layer molybdenum disulfide (MoS2). Our FPD has a considerably high photo-responsivity of ∼0.6 A W-1 at a bias voltage of 4 V and 0.01 A W-1 under the bias-free conditions. We believe that the proposed platform may provide a new strategy for the integration of 2D materials in fibers and realization of optoelectronic and sensing applications.

Synthesis of single-crystal low-loss LiB3O5 nanowire and its optical properties.

Optical-quality single-crystal LiB3O5 (LBO) nanowires are synthesized for the first time using a sol-gel method. The LBO nanowires possess diameters ranging from 200 to 800 nm and lengths of up to 200 µm, and exhibit excellent uniformity, smooth surfaces, and good mechanical properties. A typical propagating loss of 0.038 dB/µm at 532 nm is obtained for a 620 nm-diameter nanowire. This is a decrease of one order of magnitude compared with that of a ß-BaB2O4 (BBO) nanowire with similar diameter, which makes the LBO nanowire a promising candidate to construct miniaturized nonlinear photonic devices.

From Ewald sphere to Ewald shell in nonlinear optics.

Ewald sphere is a simple vector scheme to depict the X-ray Bragg diffraction in a crystal. A similar method, known as the nonlinear Ewald sphere, was employed to illustrate optical frequency conversion processes. We extend the nonlinear Ewald sphere to the Ewald shell construction. With the Ewald shell, a variety of quasi-phase-matching (QPM) effects, such as the collective envelope effect associated with multiple QPM resonances, the enhanced second- harmonic generation due to multiple reciprocal vectors etc., are suggested theoretically and verified experimentally. By rotating the nonlinear photonic crystal sample, the dynamic evolution of these QPM effects has also been observed, which agreed well with the Ewald shell model.