Hydrogen Sulfide Promotes Postnatal Cardiomyocyte Proliferation by Upregulating SIRT1 Signaling Pathway.

Hydrogen sulfide (H2S) has been identified as a novel gasotransmitter and a substantial antioxidant that can activate various cellular targets to regulate physiological and pathological processes in mammals. However, under physiological conditions, it remains unclear whether it is involved in regulating cardiomyocyte (CM) proliferation during postnatal development in mice. This study mainly aimed to evaluate the role of H2S in postnatal CM proliferation and its regulating molecular mechanisms. We found that sodium hydrosulfide (NaHS, the most widely used H2S donor, 50-200 µM) increased neonatal mouse primary CM proliferation in a dose-dependent manner in vitro. Consistently, exogenous administration of H2S also promoted CM proliferation and increased the total number of CMs at postnatal 7 and 14 days in vivo. Moreover, we observed that the protein expression of SIRT1 was significantly upregulated after NaHS treatment. Inhibition of SIRT1 with EX-527 or si-SIRT1 decreased CM proliferation, while enhancement of the activation of SIRT1 with SRT1720 promoted CM proliferation. Meanwhile, pharmacological and genetic blocking of SIRT1 repressed the effect of NaHS on CM proliferation. Taken together, these results reveal that H2S plays a promotional role in proliferation of CMs in vivo and in vitro and SIRT1 is required for H2S-mediated CM proliferation, which indicates that H2S may be a potential modulator for heart development in postnatal time window.

Efficient and polarization insensitive edge coupler based on cascaded vertical waveguide tapers.

We propose an efficient and polarization-insensitive edge coupler (EC) constructed principally with two cascaded vertical waveguide tapers. The proposed edge coupler only requires ordinary 365 nm (i-line) ultraviolet source for lithography process. We experimentally demonstrate the proposed EC on two kinds of photonic integrated circuit (PIC) platforms: silicon nitride (Si3N4) and lithium niobate thin film. Both achieve polarization-insensitive fiber chip coupling efficiency of >70% in the C-band. Our proposed EC have the advantages of efficient, cost-saving, and easy to implement and could serve as an effective solution to facilitate low-loss chip-fiber coupling.

Thin-film lithium-niobate modulator with a combined passive bias and thermo-optic bias.

It is essential to bias a thin-film lithium-niobate Mach-Zehnder electro-optic (EO) modulator at the desired operation condition to ensure optimal performance of the modulator. While thermo-optic (TO) control can solve the problem of bias drift, it consumes significant electric power. In this paper, we propose a technique to largely reduce bias power consumption by combining passive bias and TO bias. In our design, waveguide sections with different widths are introduced in the two arms of the MZ modulator to produce a desired phase difference of π/2 rad (the desired operation condition), and local heating with electrode heaters placed on the waveguides is employed to provide compensation for any phase drift caused by fabrication errors and other effects. As the TO control only serves to compensate for small errors, the electric power required is low and the response is fast. To demonstrate our technique experimentally, we fabricate several modulators of the same design on the same chip. Our experimental modulators can operate up to ∼40 GHz with a half-wave voltage of ∼2.0 V over a wide optical bandwidth, and the performances are insensitive to ambient temperature variations. The TO bias powers required range from 1 mW to 15 mW, and the thermal rise and fall times are 47 µs and 14 µs, respectively. Our technique can facilitate the development of practical high-speed EO modulators on the lithium-niobate-on-insulator platform.

SrAgAsS4: A Noncentrosymmetric Sulfide with Good Infrared Nonlinear Optical Performance Induced by Aliovalent Substitution from Centrosymmetric SrGa2S4.

A new noncentrosymmetric (NCS) quaternary sulfide, SrAgAsS4, was obtained via the strategy of aliovalent substitution based on centrosymmetric (CS) SrGa2S4. The new compound features two-dimensional [AgAsS4]2- layers, which are composed of alternately connected [AsS4] tetrahedra and [AgS4] tetrahedra. Importantly, SrAgAsS4 exhibits a strong phase-matched second-harmonic generation response (1.35 × AgGaS2 at 2100 nm) and has a suitable birefringence (0.15@2100 nm) and moderate band gap (2.31 eV). The first-principles calculations revealed the significant contribution of [AsS4] and [AgS4] tetrahedra to its optical properties. This work will promote the application of the aliovalent substitution strategy in the design of NCS-structure-based functional materials.

Livestock exclusion reduces the spillover effects of pastoral agriculture on soil bacterial communities in adjacent forest fragments.

Forest-to-pasture conversion is known to cause global losses in plant and animal diversity, yet impacts of livestock management after such conversion on vital microbial communities in adjoining natural ecosystems remain poorly understood. We examined how pastoral land management practices impact soil microorganisms in adjacent native forest fragments, by comparing bacterial communities sampled along 21 transects bisecting pasture-forest boundaries. Our results revealed greater bacterial taxon richness in grazed pasture soils and the reduced dispersal of pasture-associated taxa into adjacent forest soils when land uses were separated by a boundary fence. Relative abundance distributions of forest-associated taxa (i.e., Proteobacteria and Nitrospirae) and a pasture-associated taxon (i.e., Firmicutes) also suggest a greater impact of pastoral land uses on forest fragment soil bacterial communities when no fence is present. Bacterial community richness and composition were most related to changes in soil physicochemical variables commonly associated with agricultural fertilization, including concentrations of Olsen P, total P, total Cd, delta 15 N and the ratio of C:P and N:P. Overall, our findings demonstrate clear, and potentially detrimental effects of agricultural disturbance on bacterial communities in forest soils adjacent to pastoral land. We provide evidence that simple land management decisions, such as livestock exclusion, can mitigate the effects of agriculture on adjacent soil microbial communities.

High-efficiency unidirectional vertical emitter achieved by an aperture-coupling nanoslot antenna array.

Coupling light from in-plane guided light into free space or optical fibers is crucial for many photonic integrated circuits and vice versa. However, traditional grating couplers or waveguide grating antennas suffer from low upward coupling efficiency due to the light radiating in both upward and downward directions simultaneously. In this paper, a compact aperture-coupling nanoslot antenna array is proposed for high-efficiency unidirectional radiation, where a two-dimensional high-contrast grating (HCG) is employed as a mirror to reflect the undesired downward radiation. Upon the HCG separated by a low-index spacing layer, a thin silver layer is deposited. Finally, a series of H-shaped slots are patterned on the silver thin film to arrange the aperture fields and radiate the in-plane guided light into free space. The proposed nanoslot antenna array features a front-to-back ratio (F/B) over 10 dB within the wavelength range of 1500 ∼ 1600 nm. At the same time, a high radiation efficiency of over 75% and a maximum radiation efficiency of 87.6% are achieved within the 100 nm bandwidth. The high-efficiency unidirectional antenna array is promising for the integrated photonic applications including wireless optical communications, light detection and ranging, and fiber input/output couplers.

Electro-optic reconfigurable two-mode (de)multiplexer on thin-film lithium niobate.

We propose and demonstrate a compact electro-optic reconfigurable two-mode (de)multiplexer using the configuration of cascaded Mach-Zehnder interferometers formed on thin-film X-cut lithium niobate on silica. Our fabricated device, which is 9.5-mm long, can spatially switch between the two transverse-electric modes with an efficiency higher than 98% from 1530-1560 nm and beyond at an applied voltage of 6.5 V. The switching speed is faster than 30 ns. Our proposed mode switch could find applications in fiber-based and on-chip mode-division-multiplexing systems.

Investigation into Structural Variation from 3D to 1D and Strong Second Harmonic Generation of the AHgPS4 (A+ = Na+, K+, Rb+, Cs+) Family.

The continuous exploration of multinary chalcogenide semiconductors has provided a variety of new functional materials. In this paper, four new quaternary chalcogenides AHgPS4 (A+ = Na+, K+, Rb+, Cs+) have been prepared by solid-state syntheses. These findings complement the lack of research on this quaternary system. Influenced by the size effect of cations and the coordination mode of Hg, the four compounds crystallize in four different space groups [NaHgPS4, P4̅n2; KHgPS4, Pnn2; RbHgPS4, P21/n; CsHgPS4, P212121] and show an interesting evolution from a 3D framework structure to a 1D chain structure. Moreover, all of these compounds feature noncentrosymmetric (NCS) structures except for RbHgPS4. The materials exhibit wide band gaps of 2.7 eV < Eg < 3.0 eV. The NCS- related second-harmonic-generation (SHG) property of NaHgPS4 and KHgPS4 was also studied. They display strong powder SHG responses (3.14 × AgGaS2 for NaHgPS4; 4.15 × AgGaS2 for KHgPS4), which indicate their intriguing potential as IR nonlinear-optical materials. Moreover, first-principles theoretical calculations were performed to understand the structure-property relationships of these materials.

Planar light-wave circuit-based switchable LP11a-LP11b mode rotator.

A simple planar light-wave circuit-based switchable LP11a-LP11b mode rotator for reconfigurable mode division multiplexing is proposed, which consists of a polymer waveguide and an electrode heater located on the waveguide. Because of the asymmetric refractive index distribution in the horizontal and vertical directions, induced by the thermo-optic effect, mode rotation between the LP11a and LP11b modes can be achieved when the heater is ON but there can be no mode rotation when the heater is OFF. Numerical simulations show that our well-designed mode rotator with optical polymer materials, which has a length of 2750 µm, can achieve a mode conversion efficiency (MCE) larger than 84% over the entire C+L band (1530-1610 nm) and a maximum MCE of 96% at 1550 nm. The switching electric power is 161.5 mW. The calculated temperature within the waveguide core is from 186°C (close to the heater) to 86°C (away from the heater).

Electro-optic mode-selective switch based on cascaded three-dimensional lithium-niobate waveguide directional couplers.

We propose an electro-optic mode-selective switch based on cascaded three-dimensional lithium-niobate waveguide directional couplers fabricated with a single-step annealed proton-exchange process. To compensate for discrepancies due to uncertainties in the fabrication process, we develop a post-tuning technique to improve the performance of the coupler by means of depositing a layer of titanium oxide (TiO2) onto one of the waveguides of the coupler. By integrating two cascaded dissimilar directional couplers, we experimentally demonstrate switchable (de)multiplexing of the LP01, LP11a, and LP11b modes, where the LP11a mode can be switched at an efficiency over 75% from 1530 nm to 1612 nm with an applied voltage varying between -9 V and +30 V, and the LP11b mode can be switched at an efficiency higher than 90% from 1534 nm to 1577 nm with an applied voltage varying between -21 V to 0 V. The switching times are 230-300 ns. Our proposed waveguide platform could be employed to develop advanced switches for applications in areas where high-speed switching of spatial modes is required, such as reconfigurable mode-division-multiplexing communication.

Grating lobe suppression in optical phased arrays by loading near-wavelength grating.

Optical phased arrays based on optical waveguides are compelling components enabling efficient and accurate beam steering. However, to avoid crosstalk between the waveguides, the element pitch is typically larger than one wavelength, which gives rise to grating lobes in real space. In this Letter, we report that near-wavelength gratings can be employed to suppress the grating lobes by utilizing the angular low-pass-filter characteristics. The properly designed near-wavelength grating acts as an angle-sensitive transmission structure. Nearly 100% transmissivity can be realized at small incident angles. However, it quickly declines to a low level when the incident angle is over the critical one. Then, a simple line current array is utilized to demonstrate the grating lobe suppression effect with the grating designed for TE-polarized incidence. Finally, we demonstrate that by loading the proposed grating designed for TM-polarized incidence upon a waveguide grating array with a 2.4 µm pitch, a grating lobe suppression of 10 dB can be achieved when scanning up to ±14∘.

Graphene electrodes for electric poling of electro-optic polymer films.

We propose electric poling of electro-optic (EO) polymer films with graphene electrodes. The use of graphene electrodes can waive the use of buffer layers and minimize the poling voltage. To demonstrate the idea, we prepared EO polymer thin-film waveguides for poling with traditional Au/ITO electrodes and graphene electrodes, where the EO polymer is a guest-host system formed by doping 15 wt% of dipolar polyene chromophore AJLZ53 into the random copolymer P(S-co-MMA). Our experiments confirm that the use of graphene electrodes can significantly reduce the poling voltage. For a 3.8-µm-thick EO polymer film, we achieve high EO coefficients of 82 pm/V at 1541 nm and 110 pm/V at 1300 nm with a poling voltage of 420 V. In addition, the use of graphene electrodes allows more flexible waveguide designs and can potentially simplify the fabrication of devices based on EO polymer.

EuHgGeSe4 and EuHgSnS4: Two Quaternary Eu-Based Infrared Nonlinear Optical Materials with Strong Second-Harmonic-Generation Responses.

Metal chalcogenides play a critical role in the infrared (IR) nonlinear optical (NLO) field. However, Eu-based chalcogenide-type IR NLO materials are still scarce up to now. In this paper, two new quaternary Eu-based chalcogenides, EuHgGeSe4 and EuHgSnS4, containing the "NLO active groups" [HgQ4]6- (Q = S, Se) and [GeSe4]4-/[SnS4]4- were synthesized through traditional high-temperature solid-state reactions. They possess noncentrosymmetric structures, crystallizing in the Ama2 space group, and exhibit strong phase-matchable second-harmonic-generation (SHG) responses (3.1× and 1.77× that of AgGaS2 for EuHgGeSe4 and EuHgSnS4, respectively). Meanwhile, the optical band gaps of EuHgGeSe4 (1.97 eV) and EuHgSnS4 (2.14 eV) were determined from UV-vis-NIR diffuse reflectance spectra. Differential scanning calorimetry (DSC) analyses reveal the congruent-melting behavior of EuHgGeSe4. Furthermore, structural analysis and theoretical calculations verify the critical driving effects of [HgQ4]6- tetrahedra on the strong SHG activity. The overall results demonstrate that EuHgGeSe4 and EuHgSnS4 are potential IR NLO materials.

Insight into removal of dissolved organic matter in post pharmaceutical wastewater by coagulation-UV/H2O2.

The removal of four dissolved organic matter (DOM) fractions, non-acid hydrophobics, hydrophobic acids, hydrophilics and transphilics, was achieved by coagulation-UV/H2O2 oxidation in post-pharmaceutical wastewater (PhWW). Coagulation with Polyferric chloride (PFC), Polymeric ferric sulfate (PFS) and Polymeric aluminum ferric chloride (PAFC) was studied separately to evaluate the effects of the initial pH and coagulant dosage. The coagulation-UV/H2O2 oxidation method resulted in much higher reduction rates for dissolved organic carbon (DOC) (by 75%) and UV254 (by 92%) than coagulation or UV/H2O2 oxidation alone. The proportion of non-acid hydrophobics, hydrophobic acids, transphilics and hydrophilics removed by coagulation was 54%, 49%, 27% and 12 %, while the combined treatment removed 92%, 87%, 70% and 39%, respectively. Parallel factor analysis (PARAFAC) of fluorescence measurements revealed that the humic-like fluorescent component C4 showed the highest removal (by 44%) during the coagulation stage. After coagulation-UV/H2O2 treatment, the humic-like fluorescent component C3 had the highest removal (by 72%), whereas xenobiotic organic fluorescent components C1 and C4 remained recalcitrant to decomposition. Significant correlations (R2 > 0.8) between C1 and the hydrophobic acids and non-acid hydrophobics suggested the possibility of using fluorescence spectroscopy as an effective tool to assess variations in DOM fraction treatment efficacy in coagulation-UV/H2O2 systems. After the combined treatment, toxic inhibition of cellular activity by post PhWW decreased from 88% to 47% and biodegradability increased from 0.1 to 0.52.

Structure-property analysis of julolidine-based nonlinear optical chromophores for the optimization of microscopic and macroscopic nonlinearity.

Four NLO chromophores with different acceptors and modified julolidine donors were facilely synthesized to tune their intramolecular charge-transfer energy gaps for the investigation of the structure-property relationships. The photophysical properties of the UV-Vis absorption spectra, fluorescence spectra and solvatochromism were measured and analyzed to understand the effect of electron-donating strength and electron-withdrawing strength on intramolecular charge-transfer. Density functional theory calculations were carried out to investigate the electron density of the frontier orbitals, energy gap, molecular microscopic dipole moment and hyperpolarizability. The change tendency of the microscopic hyperpolarizability in different dielectric environments in association with the solvatochromism in absorption was analyzed. Meanwhile, the macroscopic electro-optic performance in relation to molecular structure variation and microscopic properties was further analyzed, revealing that chromophores with a larger solvatochromism exhibited higher microscopic hyperpolarizability and macroscopic electro-optic coefficients. Our investigation of the structure-property relationship gave a reliable insight into molecular design for high performance nonlinear optical chromophores.

Ultra-broadband mode converters based on length-apodized long-period waveguide gratings.

We propose an ultra-broadband mode converter based on the structure of a length-apodized long-period grating, where π-phase shifts are introduced at strategic locations of the grating profile. Using a 3-section length-apodized grating structure, we design and fabricate an LP01-LP11a and an LP01-LP11b mode converter with a sidewall grating and a surface grating formed along a polymer channel waveguide, respectively. The fabricated LP01-LP11a and LP01-LP11b mode converters provide a conversion efficiency higher than 99% over a bandwidth of ~120 nm and ~150 nm, respectively, or a conversion efficiency higher than 90% over a bandwidth of ~180 nm and ~300 nm, respectively. The transmission characteristics of these devices are weakly sensitive to polarization and temperature variations. These mode converters can find applications in ultra-broadband mode-division-multiplexing transmission systems based on few-mode fibers and the design principle can be applied to general grating-based mode-coupling devices for a wide range of applications.

Low-power variable optical attenuator based on a hybrid SiON-polymer S-bend waveguide.

We propose a low-power variable optical attenuator based on the configuration of a hybrid silicon oxynitride (SiON)-polymer S-bend waveguide and two grooves in both sides of the S-bend waveguide core. With such a configuration, the opposite thermo-optic characteristics of SiON and polymer materials can be fully utilized. As a consequence, the heat utilization efficiency is increased. Theoretical simulation shows that an optical attenuation of ∼50 dB can be achieved with an applied electrical power of 3.6 mW. A typical fabricated device, which has a total length of 8 mm, shows a maximum optical attenuation of 46 dB with an applied electrical power of 16.2 mW and an insertion loss of 5.4 dB.

Hsa_circ_0087862 contributes to the progression of colorectal cancer through regulating miR-512-3p/HK2 axis.

BACKGROUND: Colorectal cancer (CRC) theratened thousands of people every year. Emerging evidences suggested that circular RNAs (circRNAs) were involved in CRC malignancies. However, the underlying mechanisms have yet not been revealed. METHODS: Quantitative real-time PCR (qRT-PCR) was used to determine the expression of circ_0087862 and microRNA-512-3p (miR-512-3p). Western blot was performed to measure the protein expression of hexokinase 2 (HK2), B-cell lymphoma-2 (Bcl-2), BCL2-associated X (Bax) and BCL2 antagonist/killer 1 (Bak). Moreover, 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) assay, colony formation and 5-ethynyl-2'-deoxyuridine (EdU) assay were employed to assess CRC cell proliferation. Also, migration/invasion abilities and apoptosis rates were investigated by transwell assay and flow cytometry. Glucose consumption, lactate production and ATP production were detected using the corresponding kits. Dual-luciferase reporter analysis and RNA immunoprecipitation (RIP) experiments were utilized to analyze the target association of miR-512-3p and circ_0087862 or HK2. Finally, xenograft assay was carried out to analyze the function of circ_0087862 in tumor growth in vivo. RESULTS: Circ_0087862 expression was elevated in CRC tissues and cells. Circ_0087862 silencing repressed cell viabilities, proliferation, migration/invasion and glycolysis, and reinforced cell apoptosis. However, HK2 could weaken these impacts. Additionally, miR-512-3p targeted HK2, and circ_0087862 could regulate HK2 expression by miR-512-3p. Furthermore, circ_0087862 silencing decreased CRC cell xenograft tumor growth. CONCLUSION: Collectively, our data suggested that circ_0087862 knockdown impeded cell viabilities, proliferation, and glycolysis, and contributed to cell apoptosis in CRC, indicating circ_0087862 as a promising tumor promoter.

Quaternary alkaline-earth metal thiophosphate SrAgPS4: syntheses, structures, and optical properties.

Metal thiophosphates have outstanding properties for the generation of mid-infrared coherent light and are an emerging nonlinear optical material system. In this study, a new non-centrosymmetric (NCS) quaternary alkaline-earth metal thiophosphate, SrAgPS4, was obtained via a high-temperature solid-state method. The new compound crystallizes in the NCS Ama2 (No. 40) space group and features two-dimensional [AgPS4]2- layers consisting of alternately connected [PS4] and [AgS4] tetrahedra. SrAgPS4 exhibits a strong phase-matched second harmonic generation response (1.10 × AgGaS2 at 2100 nm) and a large band gap (2.97 eV). In addition, theoretical calculations reveal the intrinsic relationship between the electronic structure and optical properties. This work enriches and greatly promotes the research on infrared nonlinear optical materials based on thiophosphates.

[Ba4X][In19S32] (X = Cl, Br): two quaternary metal chalcohalides exhibiting remarkable photocurrent responses.

Inorganic metal chalcohalides, as significant semiconductor materials, have emerged as promising candidates for photoelectric applications. Herein, a new type of quaternary chalcohalide, [Ba4X][In19S32] (X = Cl, Br), has been discovered using the high-temperature halide salt flux method. Single-crystal X-ray diffraction analysis reveals that they are isostructural and crystallize in the tetragonal space group I41/amd (no. 141) featuring the octahedral hole formed by six [InS4]5- tetrahedra filled with a [ClBa4]7+ polycation, surrounded by a three-dimensional covalent framework formed by interconnecting [InS6]9- octahedra through corner-sharing and edge-sharing. Moreover, [Ba4Cl][In19S32] and [Ba4Br][In19S32] exhibit wide optical bandgaps of 2.70 eV and 2.46 eV, respectively, and moderate birefringences (0.044 @ 2100 nm and 0.042 @ 2100 nm, respectively). Specifically, [Ba4X][In19S32] (X = Cl, Br) display remarkable photocurrent responses under simulated solar-light illumination, implying their potential for photocatalytic applications. Theoretical calculations were employed to understand the interrelationship between the optical properties and electronic structure. The study on the synthesis and structure-property relationship analysis of inorganic metal chalcohalides provides new insight into the exploration of promising photoelectric materials.