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The incorporation of flowing nanoparticles or microparticles for use in catalysis as well as in the enhancement of mass transfer in microreactors opens a new avenue for chemical process intensification. In this work, the recent application of handling suspended solid particles in microreactors for carrying out efficient chemical conversions is reviewed, including the use of colloidal suspensions, Pickering emulsions, and catalyst slurries. Emphasis is laid on the effect of the presence of solid particles on the microflow characteristics, mass transfer property, and reaction enhancement, especially in multiphase fluid systems as the most frequently used one in microreactors. A future perspective regarding the potential application of such microreactor systems as well as challenges, especially related to stable flow operation and catalyst recycling, is further provided.

Environmental signals, especially daylength, play important roles in determining fertility in photoperiod-sensitive genic male sterile (PGMS) lines that are critical to sustain production of high-yielding hybrid rice (Oryza sativa) varieties. However, the mechanisms by which PGMS lines perceive changes in photoperiod and transmit those signals to elicit downstream effects are not well understood. In this study, we compared the transcriptomes from the leaves and anthers of carbon starved anther (csa), a PGMS line, to wild-type (WT) tissues under different photoperiods. Components of circadian clock in the leaves, including Circadian Clock-Associated 1 and Pseudo-Response Regulator (PRR95), played vital roles in sensing the photoperiod signals. Photoperiod signals were weakly transduced to anthers, where gene expression was mainly controlled by the CSA allele. CSA played a critical role in regulating sugar metabolism and cell wall synthesis in anthers under short-day conditions, and transcription of key genes inducing csa-directed sterility was upregulated under long-day (LD) conditions though not to WT levels, revealing a mechanism to explain the partial restoration of fertility in rice under LD conditions. Eight direct targets of CSA regulation were identified, all of which were genes involved in sugar metabolism and transport (cell wall invertases, SWEETs, and monosaccharide transporters) expressed only in reproductive tissues. Several hub genes coordinating the effects of CSA regulation were identified as critical elements determining WT male fertility and further analysis of these and related genes will reveal insights into how CSA coordinates sugar metabolism, cell wall biosynthesis, and photoperiod sensing in rice anther development.

Single-frequency fiber lasers with extremely low noise and narrow spectral linewidth have found many scientific and practical applications. There is great interest in developing single-frequency fiber lasers at new wavelengths. In this paper, we report a single-frequency Nd3+-doped phosphate fiber laser operating at 880 nm, which is the shortest demonstrated wavelength for a single-frequency fiber laser thus far, to the best of our knowledge. An output power of 44.5 mW and a slope efficiency of 20.4% with respect to the absorbed pump power were obtained with a 2.5-cm-long 1 wt.% Nd3+-doped phosphate fiber. Our simulation results show that higher single-frequency laser output can be achieved with 1.5 wt.% or 2 wt.% Nd3+-doped phosphate fiber with mitigated ion clustering.

The biolithite reservoir has a strong heterogeneity and complex pore structure, and the changing trend of formation resistivity is complicated during the waterflood development process. In the logging interpretation of a water-flooded layer, mixed-formation water resistivity is a critical parameter and its accurate calculation heavily influences the evaluation of logging water saturation. The commonly used mixed liquid resistivity models have not taken into account the contribution of irreducible clay water and, thus, they are not suitable for biolithite reservoirs with high shale contents. In this paper, a new 3D digital core was constructed based on CT scanning, and a progressive ion exchange model of the mixed-formation water compatible with the biolithite reservoir put forward. Compared with experimental data from core water flooding, the progressive ion exchange model conforms to the resistivity change law of biolithite reservoirs. Through numerical simulation and analysis of the resistivity of biolithite reservoir, it is concluded that the salinity of injected water and the formation water saturation are the main factors affecting the resistivity characteristics of water-flooded layer. In terms of the interpretation of the water-flooded layer, the water saturation was calculated using the progressive ion exchange model through finite element modelling of formation resistivity. The particular mechanism of water flooding and changing law of rock electrical properties during reservoir water injection development are presented, which provide a new reliable basis for optimization of the biolithite reservoir development plan.

An ultrathin multilayer film with well-defined structure containing anionic Poly[[4,4-bis(4-sulphobutyl)-4H-cyclopenta[2,1-b:3,4-b’]dithiophene-2,6-diyl]-1,4-phenylene sodium sa (PCPDTPhSO3Na) and ...

Single-frequency distributed Bragg reflector fiber laser at 915 nm was demonstrated by using a 2.5-cm long Nd3+-doped phosphate fiber as the gain medium. An output power of 13.5 mW was obtained at an absorbed pump power of 240 mW. Our experimental results show that Nd3+-doped phosphate glass fiber is more efficient than Nd3+-doped silica glass fiber for single-frequency laser operation in the 900 nm wavelength range.

Self-healing hydrogels with the shear-thinning property are novel injectable materials and are superior to traditional injectable hydrogels. The self-healing hydrogels based on 2-ureido-4[1H]-pyrimidinone (UPy) have recently received extensive attention due to their dynamic reversibility of UPy dimerization. However, generally, UPy-based self-healing hydrogels exhibit poor stability, cannot degrade in vivo and can hardly be excreted from the body, which considerably limit their bio-application. Here, using poly(l-glutamic acid) (PLGA) as biodegradable matrix, branching α-hydroxy-ω-amino poly(ethylene oxide) (HAPEO) as bridging molecule to introduce UPy, and ethyl acrylate polyethylene glycol (MAPEG) to introduce double bond, the hydrogel precursors (PMHU) are prepared. A library of the self-healing hydrogels has been achieved with well self-healable and shear-thinning properties. With the increase of MAPEG grafting ratio, the storage modulus of the self-healing hydrogels decreases. The self-healing hydrogels are stable in solution only for 6 h, hard to meet the requirements of tissue regeneration. Consequently, ultraviolet (UV) photo-crosslinking is involved to obtain the dual crosslinking hydrogels with enhanced mechanical properties and stability. When MAPEG grafting ratio is 35.5%, the dual crosslinking hydrogels can maintain the shape in phosphate-buffered saline solution (PBS) for at least 8 days. Loading with adipose-derived stem cell spheroids, the self-healing hydrogels are injected and self-heal to a whole, and then they are crosslinked in situ via UV-irradiation, obtaining the dual crosslinking hydrogels/cell spheroids complex with cell viability of 86.7%±6.0%, which demonstrates excellent injectability, subcutaneous gelatinization, and biocompatibility of hydrogels as cell carriers. The novel PMHU hydrogels crosslinked by quadruple hydrogen bonding and then dual photo-crosslinking of double bond are expected to be applied for minimal invasive surgery or therapies in tissue engineering.

Noble metal alloys are one of the most commonly used heterogeneous catalysts. During many reactions, the surface composition and oxidation states of the noble metal alloy particles have been reported to be dynamic. This paper describes a density functional theory study to explore the initial oxidation stages of the Pt-based surfaces, which are widely-used catalysts in various clean energy conversion processes. By applying a genetic algorithm based global optimization, we identified new surface phases at relatively high O coverages, 1 ML and 3/2 ML, on Pt and Pt alloy (111) surfaces. The existence of O transforms the metallic surfaces, creating oxide skins with different morphology and composition. Metals with higher reducibility are pulled out to the outmost surface, to bind with O atoms. The lattice constant affects the binding strength of O atoms over certain oxide skins. Moreover, the strain effect plays a crucial role in the formation of oxide overlayers.

The spectroscopic properties of Er3+-doped tellurite glasses were investigated and a 1 wt.% Er3+-doped tellurite fiber was fabricated for L-band lasers. Wavelength-tunable fiber lasers in a linear cavity based on Littrow configuration were developed and studied with different gain fiber lengths as well as output coupling ratios. Wavelength tunable range of 38 nm from 1589–1627 nm was achieved in the experiment with a 3-m Er3+-doped tellurite fiber laser pumped at 1570 nm. A maximum output power of 52.4 mW was obtained at 1614 nm. Compared to L-band Er3+-doped silica fiber lasers, the demonstrated Er3+-doped tellurite fiber lasers exhibit much higher optical signal-to-noise ratio (>30 dB), even at the longest operating wavelength of 1627 nm. Our simulation shows that the laser wavelength can be further extended to 1634 nm if the tellurite fiber loss is improved and the fiber cavity is optimized.

Background The survival of patients treated with monotherapy for hepatic malignancies is not ideal. A comprehensive program of cryoablation combined with radiotherapy for the treatment of hepatic malignancies results in less trauma to the patients. It may provide an option for the treatment of patients with advanced hepatic malignancies. Case summary We reported 5 cases of advanced-stage hepatic malignancies treated in our hospital from 2017-2018, including 3 cases of primary hepatocellular carcinoma and 2 cases of metastatic hepatic carcinoma. They first received cryoablation therapy on their liver lesions. The procedure consisted of 2 freeze-thaw cycles, and for each session, the duration of freezing was 13-15 min, and the natural re-warming period was 2-8 min. Depending on the tumor size, the appropriate cryoprobes were selected to achieve complete tumor ablation to the greatest extent possible. After cryoablation surgery, intensity-modulated radiotherapy (IMRT) for liver lesions was performed, and the radiotherapy regimen was 5400 cGy/18f and 300 cGy/f. None of the 5 patients had adverse events above grade II, and their quality of life was significantly improved. Among them, 4 patients were free of disease progression in the liver lesions under local control, and their survival was prolonged; 3 patients are still alive. Conclusion Our clinical practice demonstrated that cryoablation combined with IMRT could be implemented safely. The definitive efficacy for hepatic malignancies needs to be confirmed in larger-size sample prospective studies.

This paper reviews studies on the human thermal plume and its influence on the inhalation exposure to particulate matter in the breathing zone under different conditions. The human thermal plume transports particle pollutants from the floor to the breathing zone, increasing the inhaled particulate matter concentration. The concentration can be four times higher than that in the ambient environment. Studies have reported that the human thermal plume may prevent particulate matter from entering the breathing zone under specific conditions. Indoor airflow patterns significantly affect the dispersion of pollutants, especially in rooms equipped with displacement ventilation at low airflow velocities. It has been shown that the particle concentration is two times lower in the breathing zone of a rotating manikin than a static manikin. Understanding the characteristics and influencing factors of the human thermal plume is crucial to formulate measures to mitigate the inhalation exposure to particulate matter, achieve independent and personalized control of the human microenvironment, and create a healthy, intelligent and energy-saving indoor environment.

Rice inflorescence development determines yield and relies on the activity of axillary meristems (AMs); however, high-resolution analysis of its early development is lacking. Here, we have used high-throughput single-cell RNA sequencing to profile 37 571 rice inflorescence cells and constructed a genome-scale gene expression resource covering the inflorescence-to-floret transition during early reproductive development. The differentiation trajectories of florets and AMs were reconstructed, and discrete cell types and groups of regulators in the highly heterogeneous young inflorescence were identified and then validated by in situ hybridization and with fluorescent marker lines. Our data demonstrate that a WOX transcription factor, DWARF TILLER1, regulates flower meristem activity, and provide evidence for the role of auxin in rice inflorescence branching by exploring the expression and biological role of the auxin importer OsAUX1. Our comprehensive transcriptomic atlas of early rice inflorescence development, supported by genetic evidence, provides single-cell-level insights into AM differentiation and floret development.

Uncoupled multicore fibers are promising platforms for advanced optical communications, optical computing, and novel laser systems. In this paper, an injection-locked highly ytterbium (Yb3+)-doped uncoupled-61-core phosphate fiber laser at 1030 nm is reported. The 61-core fiber with a core-to-core pitch of 20 μm was fabricated with the stack-and-draw technique. Each core doped with 6-wt.% Yb3+ ions has a diameter of 3 μm and numerical aperture of 0.2. Linearly polarized single-frequency output of 9.1 W was obtained from the injection-locked cavity with a 10-cm-long gain fiber at a pump power of 23.6 W. The injection locking of all 61 cores was confirmed by inspecting the longitudinal modes of the individual lasers with a scanning Fabry–Perot interferometer. The performance of the injection-locked 61-core fiber laser was characterized and compared to that of the free-running operation in terms of optical spectrum, near- and far-field intensity profiles, and relative intensity noise.

D-shaped fiber deposited with single-wall carbon-nanotubes was used as fiber-optic saturable absorber to achieve Q-switched Ho3+-doped fluoride fiber laser in all-fiber configuration with superior compactness and reliability. Stable Q-switched operation at 1192 nm was established at the pump power of 290 mW. When the pump power was increased to 1280 mW, Q-switched laser with a pulse duration of $1.1~\mu \text{s}$ and pulse energy of $0.11~\mu \text{J}$ at a repetition rate of 127 kHz was obtained. This all-fiber laser exhibits high stability with a radio-frequency signal-to-noise ratio >50 dB.

Compact and robust high-power single-frequency laser oscillators are in great demand for some specific applications where narrow-linewidth lasers with extremely low noise are required. In this paper, we report a single-mode-diode-pumped watt-level single-frequency Yb

Feature screening is an important and challenging topic in current class-imbalance learning. Most of the existing feature screening algorithms in class-imbalance learning are based on filtering techniques. However, the variable rankings obtained by various filtering techniques are generally different, and this inconsistency among different variable ranking methods is usually ignored in practice. To address this problem, we propose a simple strategy called rank aggregation with re-balance (RAR) for finding key variables from class-imbalanced data. RAR fuses each rank to generate a synthetic rank that takes every ranking into account. The class-imbalanced data are modified via different re-sampling procedures, and RAR is performed in this balanced situation. Five class-imbalanced real datasets and their re-balanced ones are employed to test the RAR’s performance, and RAR is compared with several popular feature screening methods. The result shows that RAR is highly competitive and almost better than single filtering screening in terms of several assessing metrics. Performing re-balanced pretreatment is hugely effective in rank aggregation when the data are class-imbalanced.

Ta coatings on the 3Y-TZP ceramic substrate were successfully fabricated by plasma alloying technique, and its effect on the tetragonal-to-monoclinic phase transformation was investigated. The results indicate that the surface morphology and grain size of Ta coatings were influenced by the deposition temperature. Results of the surface roughness and static contact angle provide further supports. Scratch tests of Ta coatings deposited at 800 °C (S2 specimen) show the good adhesion. The Ta coating has a thickness of ∼590 nm in S2 specimen. Moreover, the friction properties of these Ta coatings in phosphate buffered saline solution exhibit the low friction coefficient. The Ta coating of S2 specimen exhibits an effectively protection for the phase transformation of the 3Y-TZP ceramic tested by hydrothermal aging.

Elastic net (Enet) and sparse partial least squares (SPLS) are frequently employed for wavelength selection and model calibration in analysis of near infrared spectroscopy data. Enet and SPLS can perform variable selection and model calibration simultaneously. And they also tend to select wavelength intervals rather than individual wavelengths when the predictors are multicollinear. In this paper, we focus on comparison of Enet and SPLS in interval wavelength selection and model calibration for near infrared spectroscopy data. The results from both simulation and real spectroscopy data show that Enet method tends to select less predictors as key variables than SPLS; thus it gets more parsimony model and brings advantages for model interpretation. SPLS can obtain much lower mean square of prediction error (MSE) than Enet. So SPLS is more suitable when the attention is to get better model fitting accuracy. The above conclusion is still held when coming to performing the strongly correlated NIR spectroscopy data whose predictors present group structures, Enet exhibits more sparse property than SPLS, and the selected predictors (wavelengths) are segmentally successive.

We demonstrate the synthesis and characterization of a new class of late transition metal-aluminum heterobimetallic complexes. A bridging ligand which both chelates the transition metal and binds the aluminum via an alkoxide was employed to impart stability to the bimetallic system. Novel rhodium–aluminum heterobimetallic complexes Rh(DPPE)(DPPP-O-AliBu2Cl) and Rh(DPPP-O-AliBu2)(DPPP-O-AliBu2Cl) are synthesized and spectroscopically characterized.

Currently, biodegradable hydrogels are one of the most promising materials in tissue engineering. From the perspective of clinical needs, hydrogels with high strength and minimally invasive implantation are preferred for the reconstruction of load-bearing tissues. In this work, a biodegradable, high-strength, and injectable hydrogel was developed by one-step photo-cross-linking of two biomacromolecules, polyethylene glycol acrylated poly(l-glutamic acid) (PLGA-APEG) and methacrylated gellan gum (GG-MA). The hydrogels, named as PLGA/GG hydrogels, exhibited high mechanical properties. The compression stress of the hydrogels was 0.53 MPa, and the fracture energy was 7.7 ± 0.2 kJ m

We report on an eye-safe, transform-limited, millijoule energy, and high average power fiber laser. The high gain and short length of the NP phosphate-glass fibers enable the SBS-free operation with kW level peak power. The output energy is up to 1.3 mJ, and the average power is up to 23 W at an 18 kHz repetition rate with 600 ns pulses (peak power &gt, 2.1 kW). The PER is &asymp, 16 dB and the M2 of the beam is 1.33 &times, 1.18. The coherent LIDAR Figure Of Merit (FOM) is 174 mJ*sqrt(Hz), which to our knowledge is the highest reported for a fiber laser. We also report 0.75 mJ energy and &gt, 3.7 kW peak power with down to 200 ns pulses and up to 1.21 mJ energy with a 3&ndash, 5 kHz repetition rate operation of the current system.

Due to their large effective magnetic moment, Dy

Background Feature selection in class-imbalance learning has gained increasing attention in recent years due to the massive growth of high-dimensional class-imbalanced data across many scientific fields. In addition to reducing model complexity and discovering key biomarkers, feature selection is also an effective method of combating overlapping which may arise in such data and become a crucial aspect for determining classification performance. However, ordinary feature selection techniques for classification can not be simply used for addressing class-imbalanced data without any adjustment. Thus, more efficient feature selection technique must be developed for complicated class-imbalanced data, especially in the context of high-dimensionality. Results We proposed an algorithm called sssHD to achieve stable sparse feature selection applied it to complicated class-imbalanced data. sssHD is based on the Hellinger distance (HD) coupled with sparse regularization techniques. We stated that Hellinger distance is not only class-insensitive but also translation-invariant. Simulation result indicates that HD-based selection algorithm is effective in recognizing key features and control false discoveries for class-imbalance learning. Five gene expression datasets are also employed to test the performance of the sssHD algorithm, and a comparison with several existing selection procedures is performed. The result shows that sssHD is highly competitive in terms of five assessment metrics. In addition, sssHD presents limited differences between performing and not performing re-balance preprocessing. Conclusions sssHD is a practical feature selection method for high-dimensional class-imbalanced data, which is simple and can be an alternative for performing feature selection in class-imbalanced data. sssHD can be easily extended by connecting it with different re-balance preprocessing, different sparse regularization structures as well as different classifiers. As such, the algorithm is extremely general and has a wide range of applicability.

Spectroscopic properties of erbium (Er

L-band wavelength-tunable Er3+-doped tellurite fiber lasers in a linear cavity based on Littrow configuration were developed. Wavelength tunable range of 38 nm from 1589 to 1627 nm was achieved with in-band pump at 1570 nm.

Inhaled air quality is directly related to occupants’ health and quality of life. In this study, a numerical breathing thermal manikin was employed, who breathed following a sinusoidal function, with 10 breathing cycles per minute. Each cycle was composed of three phases: 2.5 s inhalation, 2.5 s exhalation, and 1 s pause. The influence of pulmonary ventilation rate, breathing mode and breathing cycle period on the re-inhalation ratio were studied by computational fluid dynamics (CFD) technology in combination with the species transport model. It was found that increasing the pulmonary ventilation rate led to a lower re-inhalation ratio. The re-inhalation ratio is the largest with the value of 0.91%, when exhaled through the mouth and inhaled through the nose. The re-inhalation ratio was up to 23.9 % lower with a pause of 1 s in the breathing cycle than without pause. When the pulmonary ventilation rate increased from 6 L/min to 8 L/min, the re-inhalation ratio decreased from 0.91% to 0.71%. This information would be an important basis for the development of the human microenvironment control and technologies, including intelligent, personalized air supply devices, local air supply and exhaust methods, and other advanced ventilation and airflow technologies.

Abstrct In this study, poly-dopamine functionalized hollow mesoporous silica spheres (PDA/HMSSs) are prepared and exploited as a sensing material for formaldehyde detection in food. The materials were characterized by small-angle X-ray diffraction, scanning electron microscope, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometry, and nitrogen adsorption-desorption. The results show that PDA was successfully modified onto the surface of HMSSs. The PDA/HMSSs-based quartz crystal microbalance (QCM) sensors exhibited a low detection limit of 100 ppb, a remarkably rapid response ( N bonds, studying on the sensing mechanism revealed that weak chemisorption between PDA/HMSSs and formaldehyde played a significant role in the good specificity and reliability for formaldehyde detection. Furthermore, the as-prepared sensors were directly applied in measuring formaldehyde levels in shiitake mushroom, Chinese cabbage, Litopenaeus vannamei, and broccoli, where rapid detections within 30 s were achieved with high sensitivity, reusability, and good selectivity.

All-fiber single-transverse-mode laser oscillators operating at 785 nm were demonstrated by splicing a 0.1 mol% Tm 3+ -doped fluoride fiber with a core diameter of 4 μm and a numerical aperture of 0.07 to a pair of silica fiber Bragg gratings. About 500 mW of continuous-wave single transverse mode laser output at 784.5 nm with a 3-dB spectral bandwidth of 0.2 nm was obtained by upconversion pumping a 3-m-long gain fiber at 1125 nm. Our experiments show that the ground-state absorption of Tm 3+ at 785 nm is the origin of low efficiency in previous reports. The efficiency of this all-fiber laser can be improved by using a gain fiber with an optimized overlap between the laser, the pump, and the fiber core, and employing new pumping schemes that deplete the ground state sufficiently.

Magneto-optical glass materials with large Verdet constants at 2 μm have attracted increasing attention due to the significant advances of novel lasers operating at this wavelength region. In this paper, 13Al2O3-21B2O3-35.4SiO2-(30.6-X)Er2O3-XDy2O3 glasses have been synthesized, and their physical, optical, and magneto-optical properties were studied for making Faraday devices at 2 μm. A Verdet constant of as high as −5.9 rad/(T*m) at 1950 nm was measured with a 13Al2O3-21B2O3-35.4SiO2-30.6Dy2O3 glass. The temperature difference between crystallization and glass transition of 150 °C and the synthesis temperature of below 1500 °С make this glass very promising for making magneto-optical devices for 2 μm applications.

An ultrathin composite films with alternated layers containing anionic lithium tetracarboxyl indium phthalocyanine chloride (ClInPc(COOLi)4) and cationic poly(diallydimethyl ammonium chloride) (PDDA) were prepared using layer-by-layer assembly technique. The resulting films were characterized by Ultraviolet-visible and Fourier transform infrared spectroscopy, showing regularly consecutive adsorption. The ultrafast third-order nonlinear optical properties of the films were investigated via a 4f coherent imaging system with phase object with 190 fs laser pulses at 532nm. The results demonstrate that the ultrathin films exhibited excellent self-focusing effect (n2 ∼ 8.86 × 10−17 m2/W) and reverse saturable absorption properties (β ∼ 5.19 × 10−10 m/W), while the nonlinear optical response of the same composite in aqueous solution were found to be negligible. Our results indicate that the ClInPc(COOLi)4/PDDA film is a promising candidate for future nonlinear optical devices.

Compact and robust high-power single-frequency laser oscillators are in great demand for some specific applications where narrow-linewidth lasers with extremely low noise are required. In this paper, we report a single-mode-diode-pumped watt-level single-frequency Yb3+-doped phosphate fiber laser at 1050 nm based on an all-fiber distributed Bragg reflector cavity. A maximum output power of 1.15 W with a slope efficiency of 66% was achieved with 18-mm-long 8 wt.% Yb3+-doped phosphate fiber. Stable, single-longitudinal-mode lasing with a spectral linewidth of 9.6 kHz and polarization extinction ratio of ∼30 dB was obtained.

Metal nanorod arrays exhibit hyperbolic dispersion and optical nonlocality under certain conditions. Therefore, their optical behaviors can hardly be expressed by incident-angle-independent effective permittivity. Here we extract effective permittivity of silver nanorod arrays with diameters of 4 nm, 12 nm, and 20 nm by polarized transmission method in the visible range. The incident angles are chosen from 20° to 60° to study the influence of optical nonlocality on permittivity. We demonstrate how the diameter of the nanorods can control the effective permittivity beyond the effective medium theory. The results suggest that the effective permittivity gradually loses its accuracy as the diameter increases due to the optical nonlocality. Our experiment verifies that ultrathin nanorod arrays can resist the fluctuations caused by changes in incident angle. We also extract k-dependent effective permittivity of nanorods with larger diameters.