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• A Pr:YLF-based single-frequency orange laser at 607 nm has been first demonstrated. • A Pr:YLF-based single-frequency orange laser at 604 nm has been first demonstrated. • The single-frequency orange lasers have potential application in biomedicine. We report on blue diode-pumped single-frequency Pr:YLF lasers in orange spectral region, for the first time to the best of our knowledge. For a single-frequency σ-polarized 607 nm laser, a maximum output power up to 175 mW is achieved with a slope efficiency of about 16.6%. Linewidth of the 607 nm single-frequency laser is measured to be about 6 MHz. Single-frequency operation has also been obtained at π-polarized 604 nm laser with a maximum output power up to 91 mW and a slope efficiency of about 8.9%. The corresponding linewidth of the 604 nm laser is about 22 MHz. The two single-frequency orange lasers exhibit wavelength tuning ranges of about 0.15 nm and 0.35 nm, respectively. This work has proposed the simplest way for single-frequency laser generation in orange spectral region, which could be obtained by complicated and low-efficiency sum-frequency mixing of Nd3+ lasers. This work paves a practical way for various orange-related applications. [ABSTRACT FROM AUTHOR]

Mid-infrared ZnSe 0.9 S 0.1 transparent mixed crystal ceramics were successfully fabricated by hot pressing (HP) in combination with post hot isostatic pressing (HIP). The phase structure of the as-fabricated mixed ceramics was found to be composed of cubic sphalerite, and the existence of any secondary phase was not detected. It was noticed that after post HIP treatment, the grain size increased greatly, and many closed pores in the samples disappeared. The specimens HP sintered at 1000 °C under 60 MPa and post HIP treated at 1300 °C under 196 MPa in the Ar atmosphere for six hours had the best transmission of 62.3% at 14 μm. • Mid-infrared ZnSe 0.9 S 0.1 transparent ceramics were fabricated by hot pressing in combination with hot isostatic pressing. • The samples pre-sintered at 1000°C and hot isostatic pressing treated at 1300 °C under 196 MPa had the best transmission. • The optimum transmission of ZnSe 0.9 S 0.1 ceramic reach 62.3% at 14 μm. [ABSTRACT FROM AUTHOR]

High quality of Tb3+-single doped and Tb3+/Pr3+ co-doped CaF 2 crystals were grown by the temperature gradient technique (TGT). Pr3+ ions were used as sensitizing ions of Tb3+. Optical properties including absorption spectrum, emission spectrum, and fluorescence decay curve were recorded. Through co-doping sensitizing ions of Pr3+, the absorption cross section around 480 nm increased from 0.007 × 10−20 cm2 to 0.3 × 10−20 cm2, the large value is beneficial for the absorption of LD pump source. Judd-Ofelt theory was used to analyze the spectroscopic parameters. Fluorescence branch ratio, transition probability, radiative and fluorescence lifetimes, and quantum efficiency were determined as well. The emission cross section of Tb,Pr:CaF 2 for the green emission at 544 nm and yellow emission at 587 nm corresponding to the transition of 5D 4 →7F 5 and 5D 4 →7F 4 were calculated to be 5.56 × 10−22 cm2 and 8.78 × 10−23 cm2, respectively, which is comparable to the Tb3+ doped CaF 2 crystal. • Tb:CaF 2 crystal and Tb/Pr co-doped CaF 2 crystal were grown by TGT method. • Pr3+ ions were used to improve the absorption cross section of Tb3+ ions. • Judd-Ofelt theory was used to analyze the spectroscopic parameters. • Tb,Pr:CaF 2 crystal is a potential laser material for green and yellow oscillation. [ABSTRACT FROM AUTHOR]

Background: Triple-negative breast cancer (TNBC) is a clinically aggressive subtype of breast cancer with a bad prognosis. Chemotherapy is still the standard of care for TNBC treatment. Circular RNAs (CircRNAs) have been recently discovered to be closely involved in the initiation and development of human cancers. Herein, we focus our attention on the functions and underlying mechanisms of circUBE2D2 in TNBC progression and chemoresistance. Methods: The expression of circUBE2D2, miR-512-3p, and cell division cycle associated 3 (CDCA3) mRNA were determined by qRT-PCR. CCK-8, colony formation, transwell and flow cytometry assays were performed to detect cell proliferation, migration, invasion and apoptosis. Western blot assay was utilized to measure the protein level of CDCA3. RNA pull-down, luciferase reporter and RIP experiments were employed to examine the possible regulatory mechanism of circUBE2D2. Results: CircUBE2D2 expression was elevated in TNBC tissues and cells. TNBC patients with high circUBE2D2 expression are inclined to present advanced TNM stage, lymph node metastasis and adverse prognosis. Knockdown of circUBE2D2 repressed cell proliferation, migration and invasion in vitro, and impeded tumor growth in vivo. Moreover, silencing of circUBE2D2 reduced doxorubicin resistance of TNBC cells. In-depth mechanism analysis revealed that circUBE2D2 served as a miRNA sponge to protect CDCA3 from the attack of miR-512-3p. Additionally, the tumor-suppressive effect induced by circUBE2D2 depletion was greatly impaired upon miR512-3p down-regulation or CDCA3 overexpression. Also, depletion of circUBE2D2 decreased the resistance to doxorubicin through regulating miR-512-3p/CDCA3 axis. Conclusion: CircUBE2D2 promoted TNBC progression and doxorubicin resistance through acting as a sponge of miR-512-3p to up-regulate CDCA3 expression. Targeting circUBE2D2 combine with doxorubicin might be exploited as a novel therapy for TNBC. [ABSTRACT FROM AUTHOR]

High quality 7 at%Er:Y 2 O 3 crystal was successfully grown by Fz method. Judd-Ofelt theory was applied to analyze spectroscopic properties at 2.7 μm. The larger value of Ω 2 shows low local environment symmetry exists in Er:Y 2 O 3 crystal, and the large Ω 4 /Ω 6 indicates better spectral quality. The larger absorption cross-section and FWHM are beneficial to efficient absorption of pump source. The fluorescence spectra and lifetimes of Er:Y 2 O 3 crystal were measured and studied at 2.7 μm. The emission cross-sections at 2723 nm was calculated to be 1.41 × 10−20cm2. Compared with other Er3+ doped crystals, the large spectral quality factors Q and low fluorescence lifetime ratio illustrate that Er:Y 2 O 3 crystal has excellent laser properties at 2.7 μm. In addition, the low inversion ratio also indicates great potential of Er:Y 2 O 3 crystal for laser generation at 2.7 μm. • A high quality 7%Er:Y 2 O 3 laser crystal was successfully grown by Fz method. • Judd-ofelt (J-O) parameterization scheme was applied to analyze the spectroscopic properties of 7%Er:Y 2 O 3 laser crystal at 2.7 μm. • The large spectral quality factors Q with low fluorescence lifetime ratio illustrates that Er:Y 2 O 3 crystal has excellent laser properties at 2.7 µm. • The low inversion ratio indicates great potential of Er:Y 2 O 3 crystal for laser generation at 2.7 μm. [ABSTRACT FROM AUTHOR]

Background: Pancreatic cancer is one of the most lethal human cancers. N6-methyladenosine (m6A), a common eukaryotic mRNA modification, plays critical roles in both physiological and pathological processes. However, its role in pancreatic cancer remains elusive. Methods: LC/MS was used to profile m6A levels in pancreatic cancer and normal tissues. Bioinformatics analysis, real-time PCR, immunohistochemistry, and western blotting were used to identify the role of m6A regulators in pancreatic cancer. The biological effects of methyltransferase-like 14 (METTL14), an mRNA methylase, were investigated using in vitro and in vivo models. MeRIP-Seq and RNA-Seq were used to assess the downstream targets of METTL14. Results: We found that the m6A levels were elevated in approximately 70% of the pancreatic cancer samples. Furthermore, we demonstrated that METTL14 is the major enzyme that modulates m6A methylation (frequency and site of methylation). METTL14 overexpression markedly promoted pancreatic cancer cell proliferation and migration both in vitro and in vivo, via direct targeting of the downstream PERP mRNA (p53 effector related to PMP-22) in an m6A-dependent manner. Methylation of the target adenosine lead to increased PERP mRNA turnover, thus decreasing PERP (mRNA and protein) levels in pancreatic cancer cells. Conclusions: Our data suggest that the upregulation of METTL14 leads to the decrease of PERP levels via m6A modification, promoting the growth and metastasis of pancreatic cancer; therefore METTL14 is a potential therapeutic target for its treatment. [ABSTRACT FROM AUTHOR]

The high optical quality Er:Lu 2 O 3 and Er,Pr:Lu 2 O 3 crystals were grown by Floating zone method. The spectral properties of Er:Lu 2 O 3 and Er,Pr:Lu 2 O 3 crystals were investigated. After co-doping small concentration of Pr3+, the depopulated influence of Pr3+ to the NIR emission was much stronger than the MIR emission. The near-infrared and up-conversion fluorescence were significantly quenched. Moreover, the fluorescence lifetime of 4I 13/2 abviously decreases from 4.02 ms to 1.71 ms in 7% Er, 0.05% Pr: Lu 2 O 3 crystal, and the lifetime ratio is 1.63 with large fluorescence lifetime of 4I 11/2 which is desirable lifetime ratio in these crystals. Thus, the spectral performance was significantly improved by co-doping 0.05 at.% of Pr3+. The high laser performance at 2.7 μm of 7% Er, 0.05% Pr: Lu 2 O 3 crystal is expectable. • The high optical quality Er:Lu 2 O 3 and Er,Pr:Lu 2 O 3 crystals were firstly grown by Floating zone method. • The spectral properties of Er:Lu 2 O 3 and Er,Pr:Lu 2 O 3 crystals were firstly investigated. • After co-doping low concentration of Pr3+, the near-infrared, ESA and up-conversion fluorescence were significantly quenched. • The spectral performance of Er:Lu 2 O 3 crystal was significantly improved at 2.7 μm by co-doping 0.05 at.% of Pr3+. [ABSTRACT FROM AUTHOR]

Tb3+ doped Y 3 Al 5 O 12 (Tb:YAG) single crystal has been grown by the Czochralski method. Optical spectroscopic characterization of the crystal was performed in order to evaluate the potential for the visible laser application. Based on the Judd–Ofelt theory, the spectroscopic parameters Ω t (t = 2, 3, 6), spontaneous transition probabilities, fluorescence branch ratio and the radiation lifetime of excited state 5D 4 state were calculated. The green emission cross section of 5D 4 →7F 5 transition were calculated to be 1.23 × 10−21 cm2 , The yellow emission cross section of 5D 4 →7F 4 transition were calculated to be 7.08 × 10−23 cm2. The decay time of the 5D 4 level was measured to be 3.12 ms, which is in reasonable agreement with the radiation lifetime of 3.30 ms. All the results indicate the potential of Tb:YAG crystal as a visible laser material. • Tb:YAG crystal was grown by Czochralski method. • Judd-Ofelt theory was used to analyze the spectroscopic properties of Tb:YAG for the first time. • Tb:YAG crystal is a potential laser material for yellow and green laser output. [ABSTRACT FROM AUTHOR]

We report a fully stabilized self-referenced all-solid-state-laser frequency comb based on a home-built Kerr-lens mode-locked Yb:CaYAlO4 oscillator, which delivers ultrafast pulses with a pulse duration of 54 fs and an average power of 1.5 W. Free running carrier-envelope phase offset frequency (fceo) is observed with a signal to noise ratio of 40 dB at 100 kHz resolution bandwidth, which is phase-locked to a microwave frequency synthesizer with a residual phase jitter of 370 mrad [1 Hz–1 MHz] and with a standard frequency deviation of 0.8 mHz at 1-s gate time within 3-h, corresponding to the relative frequency instability of 2.9 × 10−18 at 1-s average time. It is the lowest phase noise and the highest frequency stability of fceo obtained in a watt-level all-solid-state bulk laser frequency comb to the best of our knowledge. A 13th repetition rate is simultaneously phase-locked to the same microwave standard with a frequency instability level of 10−12 at 1 s average time. Such fully stabilized power scaling Yb: CaYAlO4 laser frequency combs have great potential for applications in broadband dual comb spectroscopy as well as high loss cases such as long-distance time and frequency transfer. [ABSTRACT FROM AUTHOR]

Abstract: Dengue virus infection causes diseases in people, ranging from the acute febrile illness dengue fever, to life-threatening dengue hemorrhagic fever/dengue shock syndrome. We previously reported that a host cellular α-glucosidases I and II inhibitor, imino sugar CM-10–18, potently inhibited dengue virus replication in cultured cells, and significantly reduced viremia in dengue virus infected AG129 mice. In this report we show that CM-10–18 also significantly protects mice from death and/or disease progress in two mouse models of lethal dengue virus infection. Our results thus provide a strong support for the development of CM-10–18 or its derivatives as antiviral agents to treat servere dengue virus infections. [Copyright &y& Elsevier]

This study presents the complete mitochondrial (mt) genome of Polylabris halichoeres, which is the largest mt genome sequenced of monogeneans so far and the second complete sequence after Microcotyle sebastis from the Microcotylidae. It is basically similar to that of M. sebastis, with the exception of a high level of gene rearrangement located between trnC and trnL(UUR), a translocation of trnM and trnH, as well as a highly repetitive region (HRR) in the large non-coding region (NCR). We also find a series of trnI pseudogenes (ΨΨI) and one unknown short open reading frame (ORF) in the large NCR. Although the ORF cannot be unambiguously regarded as an atp8 gene, we cannot rule out the possibility that it has other functional importance, but it need further study in the future. [ABSTRACT FROM AUTHOR]

• The performance of diode-pumped (Nd3+-doped) Ca 0.7 La 0.3 Al 12 O 19 (Nd:CLA) lasers was studied for the first time. • By inserting a Cr4+:YAG absorber, we successfully achieved a passively Q-switched laser. • Comparation between a- and c-cut disordered Nd:CLA lasers were made. A new neodymium-doped (Nd3+-doped) Ca 0.7 La 0.3 Al 12 O 19 (Nd:CLA) disordered crystal was successfully grown by the Czochralski method. The performance of diode-pumped Nd:CLA (a-cut and c-cut) lasers was demonstrated for the first time. For the c-cut crystal continuous-wave (CW) operation, we obtained the highest output power of 2.08 W at the wavelength of 1053.2 nm, and the slope efficiency was 23% versus the incident pump power. By inserting a Cr4+:YAG absorber, we successfully achieved a passively Q-switched laser, and the shortest pulse width was 18.36 ns with a peak power of 364.6 W. Compared with a-cut crystal, c-cut crystal has superior laser characteristics. [ABSTRACT FROM AUTHOR]

The natural halloysite nanotubes were used as the nanocontainer to load Na 2 MoO 4 corrosion inhibitor, and the release rate of Na 2 MoO 4 was further controlled by wrapped with the CaMoO 4 end stopper through adding with Ca2+. The variable release rates were fulfilled by the formation of CaMoO 4 end stopper with different strength, and the release time can be adjusted from one to dozens of hours. Moreover, the prepared complex corrosion inhibitor is also an acid-responsive smart material, which can quickly release the large amount of corrosion inhibitors under acidic conditions through the decomposition of insoluble CaMoO 4 complex on the surface or end of halloysite. In addition, the epoxy coating mixed with 10 wt% Ca2+ treated Na 2 MoO 4 loaded halloysite can provide the highest corrosion resistance and sustained release of the corrosion inhibitor to achieve corrosion healing in the coating defects. • Release rate of Na 2 MoO 4 in halloysite was adjusted by Ca2+. • The formation and decomposition of CaMoO 4 end stopper were investigated and demonstrated. • The anticorrosion effect of coatings added with halloysite was investigated. [ABSTRACT FROM AUTHOR]

Nd3+ doped Y 3 Sc x Al 5-x O 12 (x = 0.05, 0.5, 1) single crystals were successfully grown by the micro-pulling-down (μ-PD) technique. The effect of compositional parameter x on the structure, absorption, emission and fluorescence lifetime of Nd:Y 3 Sc x Al 5-x O 12 crystals was studied. The Nd3+ concentration in the core increased with increasing of compositional parameter x. The full width at half maximum (FWHM) of the emission band centered at 1064 nm was calculated to be 6.1, 7.1, and 7.3 nm for x = 0.05, 0.5 and 1, respectively. The fluorescence lifetimes of 4F 3/2 levels are 259.3, 269.6, and 276.9 μs for x = 0.05, 0.5, and 1, respectively. The results indicate that the Nd:Y 3 Sc x Al 5-x O 12 crystals are promising materials for laser output. • Nd:Y 3 Sc x Al 5-x O 12 crystals were successfully grown by the micro-pulling-down technique. • Spectral parameters of Nd:Y 3 Sc x Al 5-x O 12 crystals were obtained. • The effect of composition on the structure and spectral parameters was discussed. [ABSTRACT FROM AUTHOR]

To create an intelligent surface region of interests (ROI) 3D quantitative inspection strategy a reality in the continuous casting (CC) production line, an improved 3D laser image scanning system (3D-LDS) was established based on binocular imaging and deep-learning techniques. In 3D-LDS, firstly, to meet the requirements of the industrial application, the CCD laser image scanning method was optimized in high-temperature experiments and secondly, we proposed a novel region proposal method based on 3D ROI initial depth location for effectively suppressing redundant candidate bounding boxes generated by pseudo-defects in a real-time inspection process. Thirdly, a novel two-step defects inspection strategy was presented by devising a fusion deep CNN model which combined fully connected networks (for defects classification/recognition) and fully convolutional networks (for defects delineation). The 3D-LDS' dichotomous inspection method of defects classification and delineation processes are helpful in understanding and addressing challenges for defects inspection in CC product surfaces. The applicability of the presented methods is mainly tied to the surface quality inspection for slab, strip and billet products. [ABSTRACT FROM AUTHOR]

Abstract: Highly (0 0 1) orientation LiGaO2 layers have been successfully fabricated on (1 0 0) β-Ga2O3 surface by vapor transport equilibration (VTE) technique. The temperature is very important for the VTE treatment. At low temperature (800°C), LiGaO2layers are textured. As the temperature was raised to 1100°C the layer becomes highly oriented in the [1 0 0] direction. It shows that the best temperature for VTE treatment is 1100°C. This technique is promising to fabricate small lattice mismatch composite substrate of LiGaO2 (0 0 1)a2O3 (100) for GaN films. [Copyright &y& Elsevier]

High optical quality Er3+ doped Lu 2 O 3 single crystal with optimum doping concentration was grown by Floating zone (Fz) method. The spectral properties and Judd-Ofelt (JO) analysis were reported. The emission cross-section at 2772 nm was calculated to be 2.47 × 10−20 cm2 with FWHM of 188 nm. The fluorescence lifetime of 4I 11/2 and 4I 13/2 energy level was fitted to be 1.62 ms and 4.02 ms. Optimum lifetime ratio (τ low /τ up) is beneficial to laser operation. Compared with reported Er3+ doped crystal, the larger spectral quality factors Q and low inversion ratio P of 7 at.% Er:Lu 2 O 3 crystal indicate that it has a favorable laser performance for 2.8 μm laser operation. • In our work high optical quality 7 at.% Er3+ doped Lu 2 O 3 single crystal with optimum doping concentration was grown by Floating zone method. • The spectroscopic properties were reported by Judd-Ofelt theory. • In order to weaken the influence of reabsorption phenomenon, we grind sample of Er:Lu 2 O 3 crystal into powder to measure fluorescence lifetime of 4I 13/2. • The measured fluorescence lifetime of 4I 13/2 is close to actual value. • We compare the optical characteristics of 7at.% Er:Lu 2 O 3 crystal with other materials in Mid-infrared. [ABSTRACT FROM AUTHOR]

• A novel IPN structured UV-induced peelable adhesive tape for silicon wafer dicing process was developed with an isocyanate terminated urethane oligomer as cross-linker. • Compared to traditional semi-IPN structured PSA tapes, the adhesion performances of IPN structured UV peelable PSA tape were improved and the remaining adhesive on the wafer after the release of the UV cured tape was greatly reduced. • Both the isocyanate content and molecular weight of the urethane oligomer gave effects on the tape peeling performances. In this paper, a linear isocyanate terminated urethane oligomer, polyethylene glycol modified isophorone diisocyanate oligomer (PEG-IPDI), was prepared by the reaction of polyethylene glycol and isophorone diisocyanate. It is mixed as a cross-linking agent with an acrylic copolymer composed of 2-ethylhexyl acrylate, butyl acrylate, methyl methacrylate, hydroxyethyl acrylate and acrylic acid to form a network pressure sensitive adhesive (PSA) through the reaction of isocyanate groups in PEG-IPDI with hydroxyl and carboxyl groups in acrylic copolymer chains. By blending this network PSA with a photo-initiator and a trifunctional acrylic monomer in a certain ratio, the UV-curable PSA was obtained. After uniformly coating it on the treated polyethylene terephthalate film, a UV-induced peelable PSA tape for a silicon wafer dicing process was prepared. The PSA network formed before UV irradiation was held together with another network produced by UV irradiation of the trifunctional acrylate monomer to give an interpenetrating network (IPN) structure. The results showed that this novel UV-curable PSA tape with IPN structure had strong peel strength before UV irradiation, and could meet the fixed requirements of silicon wafer cutting process. After UV curing, the peel strength was remarkably lowered due to the formation of IPN structure. Compared to those semi-IPN structured PSA tapes prepared with traditional multi-functional urethane acrylate oligomers, the adhesion performances of IPN structured UV peelable PSA tape prepared in this work were similar, but the remaining adhesive on the wafer after the release of the UV cured tape was greatly reduced. [ABSTRACT FROM AUTHOR]

LaMgAl 11 O 19 (LMA) crystal with nominal Sm3+ concentrations of 8 at.% was grown by the Czochralski method. Polarized absorption spectra, polarized emission spectra and fluorescence decay curve of Sm:LMA crystal were recorded at room temperature. The absorption cross-sections at 404 nm were calculated to be 2.33 × 10−20 cm2 and 0.86 × 10−20 cm2 for σ and π polarization, respectively. The spontaneous transition rates, branching ratios and the radiative lifetime of the 4G 5/2 multiplet, were calculated. The Judd-Ofelt theory has been applied to evaluate the Ω t (t = 2, 4, 6) intensity parameters. The highest stimulated emission cross-sections for the 4G 5/2 → 6H 7/2 transition around 594 nm were calculated to be 1.67 × 10−21 cm2 for σ polarization and 1.15 × 10−21 cm2 for π polarization, with full width at half maximum (FWHM) of 7.68 nm and 7.27 nm, respectively. The fluorescence lifetime of the 4G 5/2 manifold was 1.84 ms. All the results show that Sm:LMA crystal would be a promising orange-red solid state laser material. • The most intensive absorption line of Sm3+ ion, suitable for 405 nm InGaN laser diode. • The rigidity of Sm:LMA crystal is higher than some host crystals. • The value Ω 2 of Sm:LMA crystal is comparable to Sm:LiYF 4. • The large parameter σ em τ of Sm3+ in LMA is beneficial for the solid state laser. [ABSTRACT FROM AUTHOR]

Dy3+-doped Y 3 Al 5 O 12 (YAG) and Y 3 ScAl 4 O 12 (YSAG) single crystals have been successfully grown by the micro-pulling-down (μ-PD) technique for the first time. The room temperature absorption spectra, fluorescence spectra and fluorescence decay curves were measured. Dy:YAG and Dy:Y 3 ScAl 4 O 12 crystals exhibit strongest emission centered at 583 nm, corresponding to the 4F 9/2 → 6H 13/2 transition. The decay lifetime of the 4F 9/2 level was measured to be 634 μs and 667 μs, respectively. All these results indicate that the Dy:YAG and Dy:Y 3 ScAl 4 O 12 crystals are promising candidates for yellow laser operation. • Dy:YAG and Dy:YSAG crystals were grown by the micro-pulling-down method. • Dy:YAG and Dy:YSAG crystals exhibit strong emission centered at 583 nm. • Dy:YSAG crystal has a wide emission bandwidth due to the disordered crystalline structure. [ABSTRACT FROM AUTHOR]

For positive integers s and t, the Ramsey number R (s , t) is the smallest positive integer n such that every graph of order n contains either a clique of order s or an independent set of order t. The triangle-free process begins with an empty graph of order n, and iteratively adds edges chosen uniformly at random subject to the constraint that no triangle is formed. It has been an important tool in studying the asymptotic lower bound for R (3 , t) . Cyclic graphs are vertex-transitive. The symmetry of cyclic graphs makes it easier to compute their independent numbers than related general graphs. In this paper, the cyclic triangle-free process is studied. The sizes of the parameter sets and the independence numbers of the graphs obtained by the cyclic triangle-free process are studied. Lower bounds on R (3 , t) for small t's are computed, and R (3 , 35) ≥ 237 , R (3 , 36) ≥ 244 , R (3 , 37) ≥ 255 , R (3 , 38) ≥ 267 , etc. are obtained based on the graphs obtained by the cyclic triangle-free process. Finally, some problems on the cyclic triangle-free process and R (3 , t) are proposed. [ABSTRACT FROM AUTHOR]

Pyrrolidines and piperidines are important building blocks in organic synthesis. Numerous methods exist for constructing substituted pyrrolidines and piperidines. However, efficient syntheses of pyrrolidines and piperidines bearing chiral tertiary alcohols are limited. Here we report an efficient enantioselective nickel-catalyzed intramolecular reductive cyclization of N-alkynones. A P-chiral bisphosphorus ligand DI-BIDIME is designed and applied in the synthesis of tertiary allylic siloxanes bearing pyrrolidine and piperidine rings in high yields and excellent enantioselectivities, with triethylsilane as reducing reagent. The highest turn over number achieved is 1000 (0.1 mol% catalyst loading) with > 99:1 er. This reaction provides a practical way to synthesize pyrrolidine and piperidine derivatives with chiral tertiary alcohols from easily accessible starting materials under mild conditions. The products can be scaled up and transformed to various useful chiral intermediates. The P-chiral bisphosphorus ligand developed in this study represents one of the few ligands for highly enantioselective cyclization of alkynones. Transition metal-catalyzed cyclization of alkynes and carbonyls offers a useful route to cyclic allylic alcohols, but typically uses precious metal catalysts. Here, enantioselective nickel-catalyzed reductive cyclization of N-alkynones gives tertiary allylic alcohols in up to 99:1 er with catalyst loadings of 0.1 mol% [ABSTRACT FROM AUTHOR]

In this paper, we report the fabrication of high-quality 5 at. % Er3+ ions doped SrF2 transparent ceramics, the potential candidate materials for a mid-infrared laser-gain medium by hot-pressing at 700 °C for 40 h using a chemically-derived powder. The phase structure, densification, and microstructure evolution of the Er:SrF2 ceramics were systematically investigated. In addition, the grain growth kinetic mechanism of Er:SrF2 was clarified. The results showed lattice diffusion to be the grain growth mechanism in the Er:SrF2 transparent ceramic of which highest in-line transmittance reached 92% at 2000 nm, i.e., very close to the theoretical transmittance value of SrF2 single crystal. Furthermore, the emission spectra showed that the strongest emission band was located at 2735 nm. This means that it is possible to achieve a laser output of approximately 2.7 μm in the 5 at. % Er3+ ions doped SrF2 transparent ceramics. [ABSTRACT FROM AUTHOR]

Review: 215 refs. [ABSTRACT FROM AUTHOR]

We demonstrate the direct generation of optical vortex pulses with stable energy and changeable orbital angular momentum. Single Laguerre-Gaussian (LG0,l) laser modes were directly generated using a laser diode with output intensity profile of doughnut distribution. With passive Q-switching, vortex pulses with stable energy were obtained. Moreover, the topological charge was changeable by variation of the pump power. By a mode-converter and second harmonic generation, the LG0,2l mode was identified. It can be proposed that this pulsed laser should have promising applications in various fields based on its compact structure, stable and high pulse energy, and changeable orbital angular momentum. [ABSTRACT FROM AUTHOR]

The laser materials Sc2SiO5, Sc1.931Tm0.069SiO5, and Sc1.955Yb0.045SiO5 crystallize in monoclinic the space group C2/c with Z = 8 (single crystal XRD). [ABSTRACT FROM AUTHOR]