Hybrid Additive and Subtractive Manufacturing Method Using Pulsed Arc Plasma.

In this study, a novel hybrid additive and subtractive manufacturing method using pulsed arc plasma (PAP-HASM) was developed to better integrate additive and subtractive processes. The PAP-HASM process is based on the flexible application of pulsed arc plasma. In this PAP-HASM method, wire arc additive manufacturing using pulsed arc plasma (PAP-WAAM) and dry electrical discharge machining (EDM) milling were used as additive and subtractive techniques, respectively; both are thermal machining processes based on pulsed arc plasma, and both are dry machining techniques requiring no working fluids. The PAP-HASM can be easily realized by only changing the pulsed power supply and tool electrodes. A key technological challenge is that the recast layer on the part surface after dry EDM milling may have a detrimental effect on the component fabricated by PAP-HASM. Here, the hybrid manufacturing method developed in this study was validated with commonly used 316L stainless steel. Preliminary experimental results showed that the PAP-HASM specimens exhibited excellent tensile properties, with an ultimate tensile strength of 539 ± 8 MPa and elongation of 46 ± 4%, which were comparable to the PAP-WAAM specimens. The recast layer on the surface after dry EDM milling has no significant detrimental effect on the mechanical properties of the parts fabricated by PAP-HASM. In addition, compared with components fabricated by PAP-WAAM, those fabricated by PAP-HASM showed significantly better surface roughness.

Additive manufacturing of geopolymers with hierarchical porosity for highly efficient removal of Cs.

Geopolymers (GPs) have emerged as promising adsorbents for wastewater treatment due to their superior adsorption stability, tunable porosity, high adsorption capacity, and low-energy production. Despite their great promise, developing GPs with well-controlled hierarchical structures and high porosity remains challenging, and the mechanism underlying the ion adsorption process remains elusive. Here we report a cost-effective and universal approach to fabricate Na or K GPs with sophisticated architectures, high porosity, and arbitrary cation species exchange by means of additive manufacturing and a surfactant. The introduction of sodium lauryl sulfate (SLS) enhanced the porosity of the GP adsorbents, yielding NaGP-lattice-10%SLS adsorbent with a high total porosity of 80.8 vol%. Combining static and dynamic adsorption tests, the effects of morphology, surfactant content, and cation species on Cs+ adsorption performance were systemically investigated. With an initial Cs+ concentration of 900 mg/L, the printed NaGP exhibited a maximum Cs+ adsorption capacity of 80.1 mg/g, outperforming other adsorbents reported so far. The quasi-second-order fit of the NaGP adsorbent showed overall higher R2 values than the quasi-first-order fit, indicating that the adsorption process was dominated by ion exchange. Combined with first-principles calculations, we verified that the content of water in the GP sod cages also affected the ion-exchange process between Na+ and Cs+.

Thermal-birefringence-induced depolarization in a 450 W Ho:YAG MOPA system.

We demonstrated an efficient, high-power Ho:YAG master-oscillator power amplifier (MOPA) system and investigated its thermal-birefringence-induced depolarization. The maximum output power was 450 W with a depolarized power of 32.1 W and depolarization of 0.071 via three power amplifiers. To our knowledge, this is the highest average power generated from a Ho:YAG MOPA system. In theory, a simplified model was built to calculate the depolarization in the amplifier, and the theoretical results agreed with the actual value well. Moreover, the overall optical-to-optical efficiency of the MOPA system was near 60%, and the beam quality M2 factors of s-polarized laser were measured to be ∼ 1.8 at 400 W. In pulse operation, the per pulse energy was ∼ 11 mJ at the pulse repetition frequency of 40 kHz with the corresponding peak power of 220 kW.

Combination of Trabeculectomy and Primary Pars Plana Vitrectomy in the Successful Treatment of Angle-Closure Glaucoma with BEST1 Mutations: Self-Controlled Case Series.

INTRODUCTION: This study aimed to illustrate the efficacy of the combination of lens extraction, trabeculectomy, and anterior vitrectomy in patients with secondary angle-closure glaucoma (ACG) with autosomal recessive bestrophinopathy or Best vitelliform macular dystrophy. METHODS: This is a retrospective self-controlled case series study. Five patients undergoing a single trabeculectomy in one eye and triple surgery in the other eye were enrolled. All patients underwent a complete ophthalmic examination that included best-corrected visual acuity (BCVA), intraocular pressure (IOP), ultrasound biomicroscopy, and static gonioscopy. Multimodal fundus imaging was performed, including color fundus photography, fundus autofluorescence, and optical coherence tomography. Genetic testing was also analyzed. RESULTS:  Among the 10 eyes, the mean IOP was 31.4 ± 4.7 mmHg before surgery. The mean axial length (AL) was 21.53 mm and the anterior chamber depth (ACD) was 2.31 mm. There were no statistically significant differences in preoperative IOP, BCVA, ACD, and AL between the two groups (all P > 0.05). The mean follow-up time was 64.0 months. All five eyes with a single trabeculectomy developed malignant glaucoma (MG). No complications were found in the other five eyes with triple surgery, and the anterior chamber was deepened and stable after surgery until the last visit. The mean IOP at the last visit was normalized to 16 mmHg without using any medications. CONCLUSIONS:  Triple surgery is superior to single trabeculectomy for patients with ACG and BEST1 mutation, effectively bypassing MG complications. The vitreous may play a vital role in the mechanism of ACG in those patients and the high incidence of MG after filtering surgery.

113 W Ho:YLF oscillator with good beam quality efficiently pumped by a Tm:YAP laser.

We demonstrate a linearly polarized Tm:YAP slab laser pumped by fiber-coupled laser diodes. The maximum output power is 202 W at 1937.5 nm with a slope efficiency of 47.4% and an optical-to-optical efficiency of 35.6%. The beam quality M2 factors are 10.1 and 8.33 in x and y directions, respectively. Using the Tm:YAP laser as the pump source, the maximum power of the Ho:YLF oscillator is 113 W at 2063.3 nm, corresponding to an optical-to-optical efficiency of 55.9%. In addition, the beam quality factors of the Ho:YLF laser are ∼1.5 at maximum power.

Passively Q-switched Tm:YAP laser with a lead zirconate titanate saturable absorber.

In the paper, we prepare a lead zirconate titanate saturable absorber, which is used to demonstrate a passively Q-switched (PQS) Tm:YAP laser. In the PQS mode, an average output power of 0.81 W and pulse width of 1.69 µs at 175 kHz are obtained at 1991.9 nm with a pump power of 12.76 W, corresponding to an optical-optical conversion efficiency of 6.35%. In addition, the beam quality factors M2 of the PQS Tm:YAP laser in the x and y directions are 1.17 and 1.15, respectively.

Tm3+: Bi4Si3O12 crystal as a promising laser material near 2 µm: growth, spectroscopic properties and laser performance.

We report on the crystal growth, spectroscopic properties and laser performance of Tm3+-doped Bi4Si3O12 (BSO) crystal. The crystal was grown by the vertical Bridgeman method. The spectroscopic properties are investigated based on absorption and luminescence spectroscopy. Judd - Ofelt (JO) analysis is performed to calculate the spontaneous emission probabilities, branching ratio and the radiative lifetimes. The absorption spectrum, emission spectrum and gain cross-section spectra of Tm3+: BSO crystal are determined for the 2 µm transition. Luminescence decay kinetic of 3F4 upper level was analysed in detail. The continuous-wave 2 µm laser with a maximum output power of 650 mW and a slope efficiency of 29.7% is demonstrated for the first time. The beam quality factor (M2) of Tm3+: BSO laser was about 1.03 at the maximum output level.

High-power actively Q-switched Ho-doped gadolinium tantalate laser.

In this paper, we present the acousto-optical (AO) Q-switched performance of a holmium (Ho):gadolinium tantalate (GdTaO4) (Ho:GTO) laser pumped by a thulium (Tm)-fiber laser emitting at 1.94 µm. In the efficient continuous wave (CW) regime, a maximum output power of 30.5 W at 2068.8 nm was achieved, corresponding to a slope efficiency of 74.9% with respect to the absorbed pump power. In the Q-switching regime, pulse energies of 2.4 mJ, 1.2 mJ, and 0.9 mJ were obtained with pulse repetition frequencies of 10 kHz, 20 kHz, and 30 kHz, respectively. The minimum pulse widths were 18 ns, 23 ns, and 26 ns, corresponding to peak powers of approximately 133.3 kW, 52.2 kW, and 34.6 kW, respectively.

Design and synthesis of novel substituted benzyl pyrrolopyrimidine derivatives as selective BTK inhibitors for treating mantle cell lymphoma.

Ibrutinib, a potent irreversible Bruton's tyrosine kinase (BTK) inhibitor, was approved by the FDA for treating mantle cell lymphoma (MCL). Although ibrutinib exhibited excellent antitumor activity, it was associated with certain adverse reactions, with off-target effects against EGFR, Itk and Src family kinases. Our studies yielded a novel series of substituted benzyl pyrrolopyrimidine derivatives capable of potent inhibition of BTK. Compared with ibrutinib, compound 15c exhibited potent BTK inhibitory activity and enhanced antiproliferative activity, a 12-24-fold increase, against MCL cell lines, with IC50 values lower than 1 µM. Low micromolar doses of 15c inhibited the BCR signaling pathway and strongly induced the apoptosis of Z138 cells. Ibrutinib and 15c induced autophagy in a dose-dependent manner in Z138 cells. Moreover, compound 15c induced the production of reactive oxygen species (ROS), which may be a reason for its potent antiproliferative activity. Importantly, compound 15c showed greater BTK selectivity than ibrutinib, indicating a potentially safer treatment of MCL.

Design, Synthesis and Biological Evaluation of 1-methyl-1H-pyrazole-5-Carboxamide Derivatives as Novel Anti-Prostate Cancer Agents.

BACKGROUND: The Androgen Receptor (AR) signaling functionis a critical driving force for the progression of Prostate Cancer (PCa) to bring about anti-prostate cancer agents, and AR has been proved to be an effective therapeutic target even for Castration-Resistant Prostate Cancer (CRPC). OBJECTIVE: In order to discover novel anti-prostate cancer agents, we performed structural modifications based on the lead compounds T3 and 10e. METHODS: A set of 1-methyl- 1H-pyrazole-5-carboxamide derivatives were synthesized and evaluated for their inhibitory activities against both expressions of Prostate-Specific Antigen (PSA) and growth of PCa cell lines. RESULTS: Compound H24 was found to be able to completely block PSA expression at 10µM, and showed prominent antiproliferative activity in both the LNCaP cell line (GI50 = 7.73µM) and PC-3 cell line (GI50 = 7.07µM). CONCLUSION: These preliminary data supported a further evaluation of compound H24 as a potential agent to treat prostate cancer.

Clinical characteristics, rates of blindness, and geographic features of PACD in China.

OBJECTIVE: To analyze the rates of blindness with the demographics and clinical characteristics of patients with primary angle-closure disease (PACD) to provide a comprehensive epidemiologic reference in China. METHODS: A retrospective analysis was conducted in the Chinese Glaucoma Study Consortium database, which is a national multicenter glaucoma research alliance of 111 hospitals participating between December 21, 2015 and September 9, 2018. The diagnosis of PACD was made by qualified physicians through examination. Comparison of sex, age, family history, subtypes of PACD, and blindness were analyzed. RESULTS: A total of 5762 glaucoma patients were included, of which 4588 (79.6%) had PACD. Of PACD patients, 72.1% were female with the sex ratio (F/M) of 2.6, and the average age of patients was 63.8±9.3 years with the majority between 60 and 70 years. Additionally, 30% of these patients had low vision in one eye, 8.8% had low vision in both eyes, 1.7% had blindness in one eye, and 0.3% had blindness in both eyes. There were statistical differences with regards to age between male and female patients with PACD, with male patients being older on average. Primary angle-closure glaucoma was more commonly diagnosed in males (60%) compared to females (35.9%), whereas acute primary angle closure (APAC) was more commonly diagnosed in females (54.3%) compared to males (37.7%). The visual acuity in APAC patients was lower and the rate of low vision and blindness was higher than other subtypes. CONCLUSION: PACD was the major type of glaucoma in Chinese hospitals. There were more female patients with PACD, mostly between 60 and 70 years old, with higher rates of APAC in women. APAC resulted in the worst visual outcomes of all PACD subtypes.

Atomically Thin Hexagonal Boron Nitride and Its Heterostructures.

Atomically thin hexagonal boron nitride (h-BN) is an emerging star of 2D materials. It is taken as an optimal substrate for other 2D-material-based devices owing to its atomical flatness, absence of dangling bonds, and excellent stability. Specifically, h-BN is found to be a natural hyperbolic material in the mid-infrared range, as well as a piezoelectric material. All the unique properties are beneficial for novel applications in optoelectronics and electronics. Currently, most of these applications are merely based on exfoliated h-BN flakes at their proof-of-concept stages. Chemical vapor deposition (CVD) is considered as the most promising approach for producing large-scale, high-quality, atomically thin h-BN films and heterostructures. Herein, CVD synthesis of atomically thin h-BN is the focus. Also, the growth kinetics are systematically investigated to point out general strategies for controllable and scalable preparation of single-crystal h-BN film. Meanwhile, epitaxial growth of 2D materials onto h-BN and at its edge to construct heterostructures is summarized, emphasizing that the specific orientation of constituent parts in heterostructures can introduce novel properties. Finally, recent applications of atomically thin h-BN and its heterostructures in optoelectronics and electronics are summarized.

161 W middle infrared ZnGeP2 MOPA system pumped by 300 W-class Ho:YAG MOPA system.

We demonstrated a high-power Q-switched two-stage Ho:YAG master-oscillator power-amplifier (MOPA) system dual-end pumped by Tm:YLF lasers. A new method was introduced by rotating and swapping spatial axial directions of pump beams to improve the beam quality of the Ho:YAG oscillator and first-stage amplifier. Two parallel second-stage Ho:YAG amplifiers were employed to output high power. A total maximum average output power of 332 W at 2091 nm with pulse repetition frequency of 20 kHz was achieved. Then a ZnGeP2 MOPA system was demonstrated using the Ho:YAG MOPA as the pump source. A maximum average output power of 161 W at 3-5 µm was obtained with 290 W incident Ho pump power, corresponding to beam quality factors M2 of 3.42 and 3.83 for horizontal and vertical directions, respectively.

Continuously tunable high-power single-longitudinal-mode Ho:YLF laser around the P12 CO2 absorption line.

A continuously tuned single-longitudinal-mode (SLM) Ho:YLF laser around the P12 CO2 absorption line was demonstrated. The continuous tuning range of 5.75 pm within one longitudinal mode spacing of the Ho:YLF resonator was realized by using a novel intra-cavity wedge prism device fixed on the piezoelectric transducer (PZT) as the cavity length controller. High SLM power of 11.3 W was obtained from a Ho:YLF amplifier with three crystals at the pump power of 31.8 W and master oscillator power of 323 mW, corresponding to a gain of 15.44 dB and an optical-to-optical conversion efficiency of 34.5%. The beam quality factors M2 of the SLM Ho:YLF amplifier in the x and y directions were estimated to be 1.04 and 1.05, respectively.

Research on performance improvement technology of a BaGa4Se7 mid-infrared optical parametric oscillator.

In this Letter, we demonstrate an average output power of 5.12 W at 3-5 µm from a type-I phase-matching BaGa4Se7 (BGSe) optical parametric oscillator (OPO), which is pumped by a 2090 nm Q-switched Ho:YAG laser with pulse repetition frequency of 1 kHz. At maximum output level, the corresponding slope efficiency and optical-to-optical conversion efficiency are 30.0% and 18.3%, respectively. Moreover, under ring cavity conditions, the BGSe OPO produced a 3.04 W mid-infrared laser with high beam quality factors M2 of 1.47 in the horizontal direction and 1.51 in the vertical direction. Besides, the wavelength-tuning curve for type-I BGSe was also investigated, corresponding to an idler wavelength-tuning range of 4.5-5.3 µm, and the signal light wavelength was 4.5 to 4.1 µm.

570†MHz harmonic mode-locking in an all polarization-maintaining Ho-doped fiber laser.

In this paper, we demonstrate a 570.0 MHz harmonically mode-locked all-polarization-maintaining Ho-doped fiber laser based on semiconductor saturable absorbed mirror. Firstly, the laser operates in the 15.4 MHz fundamental mode-locked soliton regime, emitting 2051.5 nm, 1.62 ps soliton pulse without Kelly sidebands. And then, the stable 37th-order harmonic mode-locked soliton with maximum repetition rate up to 570.0 MHz at 2053nm is generated. Moreover, colorful soliton rain behaviors are also discussed.

Tunable twisted-mode Ho:YAG laser at continuous-wave and pulsed operation.

A single-longitudinal-mode Ho:YAG laser with a twisted-mode cavity under the continuous-wave and pulsed operation was demonstrated. The maximum continuous-wave single-longitudinal-mode output power of 0.76 W was obtained at the wavelength of 2097.46 nm, corresponding to a slope efficiency of 28.9%. The output wavelength was tuned from 2096.94 nm to 2098.48 nm by utilizing a 0.5-mm-thick etalon. Furthermore, the single-frequency pulsed operation of the twisted-mode Ho:YAG laser was realized by the electro-optic switch. For the 2 kHz pulse repetition frequency, the single-frequency pulse energy reached 0.2 mJ with the pulse width of 116.5 ns. The beam quality factors M2 of the pulsed twisted-mode Ho:YAG laser in the x and y directions were 1.15 and 1.10, respectively.

Measurement of optical homogeneity of ZnGeP2 crystal using a 2.02 µm single-longitudinal-mode Tm:LuAG ring laser.

We demonstrate a single-longitudinal-mode Tm:LuAG unidirectional ring laser based on the Faraday effect and its application in measuring the optical homogeneity of ZnGeP2 (ZGP) crystal. The maximum single-longitudinal-mode power was 511 mW at 2022.4 nm, with a slope efficiency of 9.7%, and the M2 factors were 1.13 and 1.23 in the x and y directions, respectively. The laser was s polarized with a polarization degree of 30 dB. Also, the optical homogeneity of ZGP crystal was measured by the Mach-Zehnder interference method, which adopts the single-longitudinal-mode laser as the monochrome source. According to the interference fringes, the quantitative calculation or qualitative analysis of the optical homogeneity of ZGP crystal was achieved, which could quickly and conveniently judge the quality of ZGP crystal, and provided high-quality crystals for high-power mid-infrared lasers. To our knowledge, it is the first report of the optical homogeneity measurement of ZGP crystal by a 2 µm single-longitudinal-mode laser.