Estimation of the rice aboveground biomass based on the first derivative spectrum and Boruta algorithm.

Aboveground biomass (AGB) is regarded as a critical variable in monitoring crop growth and yield. The use of hyperspectral remote sensing has emerged as a viable method for the rapid and precise monitoring of AGB. Due to the extensive dimensionality and volume of hyperspectral data, it is crucial to effectively reduce data dimensionality and select sensitive spectral features to enhance the accuracy of rice AGB estimation models. At present, derivative transform and feature selection algorithms have become important means to solve this problem. However, few studies have systematically evaluated the impact of derivative spectrum combined with feature selection algorithm on rice AGB estimation. To this end, at the Xiaogang Village (Chuzhou City, China) Experimental Base in 2020, this study used an ASD FieldSpec handheld 2 ground spectrometer (Analytical Spectroscopy Devices, Boulder, Colorado, USA) to obtain canopy spectral data at the critical growth stage (tillering, jointing, booting, heading, and maturity stages) of rice, and evaluated the performance of the recursive feature elimination (RFE) and Boruta feature selection algorithm through partial least squares regression (PLSR), principal component regression (PCR), support vector machine (SVM) and ridge regression (RR). Moreover, we analyzed the importance of the optimal derivative spectrum. The findings indicate that (1) as the growth stage progresses, the correlation between rice canopy spectrum and AGB shows a trend from high to low, among which the first derivative spectrum (FD) has the strongest correlation with AGB. (2) The number of feature bands selected by the Boruta algorithm is 19~35, which has a good dimensionality reduction effect. (3) The combination of FD-Boruta-PCR (FB-PCR) demonstrated the best performance in estimating rice AGB, with an increase in R² of approximately 10% ~ 20% and a decrease in RMSE of approximately 0.08% ~ 14%. (4) The best estimation stage is the booting stage, with R2 values between 0.60 and 0.74 and RMSE values between 1288.23 and 1554.82 kg/hm2. This study confirms the accuracy of hyperspectral remote sensing in estimating vegetation biomass and further explores the theoretical foundation and future direction for monitoring rice growth dynamics.

Structural basis for substrate recognition by a S-adenosylhomocysteine hydrolase Lpg2021 from Legionella pneumophila.

S-Adenosyl-l-homocysteine hydrolase (SAHH) is a crucial enzyme that governs S-adenosyl methionine (SAM)-dependent methylation reactions within cells and regulates the intracellular concentration of SAH. Legionella pneumophila, the causative pathogen of Legionnaires' disease, encodes Lpg2021, which is the first identified dimeric SAHH in bacteria and is a promising target for drug development. Here, we report the structure of Lpg2021 in its ligand-free state and in complexes with adenine (ADE), adenosine (ADO), and 3-Deazaneplanocin A (DZNep). X-ray crystallography, isothermal titration calorimetry (ITC), and molecular docking were used to elucidate the binding mechanisms of Lpg2021 to its substrates and inhibitors. Virtual screening was performed to identify potential Lpg2021 inhibitors. This study contributes a novel perspective to the understanding of SAHH evolution and establishes a structural framework for designing specific inhibitors targeting pathogenic Legionella pneumophila SAHH.

Synthesis of flowerlike vanadium diselenide microspheres for efficient electromagnetic wave absorption.

The revelation of MoS2as an efficient electromagnetic wave (EMW) absorbing material has ratcheted up people's attention to other transition metal dichalcogenides (TMDs). To date, extensive studies have been conducted on the semiconducting VIB-Group TMDs while research into metallic VB-Group TMDs has been relatively rare. In this work, we successfully fabricated VB-Group VSe2microspheres through a facile one-step hydrothermal method and used them as EMW absorbers. The flowerlike VSe2microspheres based on VSe2nanosheets exhibited a minimum reflection loss of 46.58 dB with an effective absorption bandwidth of 4.86 GHz. The influence of material morphology, microstructure, and dielectric properties on the EMW absorption performance was systematically investigated. The hierarchically layered structure promoted dielectric loss and EMW absorption by means of multiple reflection, interfacial polarization and related relaxation, and enhanced attenuation ability. This work not only demonstrates that VSe2is potentially a high-efficiency single component EMW absorber, but also provides fresh insights into exploration on the EMW loss mechanisms of the metallic TMD-based absorbing materials.

High-Efficiency Pure-Red CsPbI3 Quantum Dot Light-Emitting Diodes Enabled by Strongly Electrostatic Potential Solvent and Sequential Ligand Post-treatment Process.

Efficient pure-red emission light-emitting diodes (LEDs) are essential for high-definition displays, yet achieving pure-red emission is hindered by challenges like phase segregation and spectral instability when using halide mixing. Additionally, strongly confined quantum dots (QDs) produced through traditional hot-injection methods face byproduct contamination due to poor solubility of metal halide salts in the solvent octadecene (ODE) at low temperatures. Herein, we introduced a novel method using a benzene-series strongly electrostatic potential solvent instead of ODE to prevent PbI2 intermediates and promote their dissolution into [PbI3]-. Increasing methyl groups on benzene yields precisely sized (4.4 ± 0.1 nm) CsPbI3 QDs with exceptional properties: a narrow 630 nm PL peak with photoluminescence quantum yield (PLQY) of 97%. Sequential ligand post-treatment optimizes optical and electrical performance of QDs. PeLEDs based on optimized QDs achieve pure-red EL (CIE: 0.700, 0.290) approaching Rec. 2020 standards, with an EQE of 25.2% and T50 of 120 min at initial luminance of 107 cd/m2.

Scalable parallel ultrafast optical random bit generation based on a single chaotic microcomb.

Random bit generators are critical for information security, cryptography, stochastic modeling, and simulations. Speed and scalability are key challenges faced by current physical random bit generation. Herein, we propose a massively parallel scheme for ultrafast random bit generation towards rates of order 100 terabit per second based on a single micro-ring resonator. A modulation-instability-driven chaotic comb in a micro-ring resonator enables the simultaneous generation of hundreds of independent and unbiased random bit streams. A proof-of-concept experiment demonstrates that using our method, random bit streams beyond 2 terabit per second can be successfully generated with only 7 comb lines. This bit rate can be easily enhanced by further increasing the number of comb lines used. Our approach provides a chip-scale solution to random bit generation for secure communication and high-performance computation, and offers superhigh speed and large scalability.

Influences of Composite Electrodeposition Parameters on the Properties of Ni-Doped Co-Mn Composite Spinel Coatings.

To enhance the comprehensive performance of solid oxide fuel cells (SOFCs) ferritic stainless steel (FSS) interconnectors, a novel approach involving composite electrodeposition and thermal conversion is proposed to prepare Ni-doped Co-Mn composite spinel protective coatings on FSS surfaces. The process involves the composite electrodeposition of a Ni-doped Co-Mn precursor coating, followed by thermal conversion to obtain the Co-Mn-Ni composite spinel coating. Crofer 22H was used as the substrate and orthogonal experiments were designed to investigate the influences of deposition solution pH, stirring rate, cathode current density, and the element content of Mn and Ni on the surface morphology and properties of the composite coatings, respectively. The characterization of the prepared coatings was conducted through macroscopic and microscopic morphology observations of the component surface, energy dispersive spectroscopy (EDS) analysis, and area specific resistance (ASR) testing, etc. Finally, the optimized composite electrodeposition parameters and the Mn-Ni content ratio in the solution were obtained. Experimental results indicated that the composite spinel coating prepared with the optimized process parameters exhibited excellent adhesion to the substrate, and the diffusion and migration of Cr element has been effectively inhibited. Compared with the substrate, the ASR of the coated components has also been decreased simultaneously, which provided an effective method for the surface modification of SOFC FSS interconnectors.

Silver Mineralized Protein Hydrogel with Intrinsic Cell Proliferation Promotion and Broad-Spectrum Antimicrobial Properties for Accelerated Infected Wound Healing.

The presence of multidrug-resistant bacteria has challenged the clinical treatment of bacterial infection. There is a real need for the development of novel biocompatible materials with broad-spectrum antimicrobial activities. Antimicrobial hydrogels show great potential in infected wound healing but are still being challenged. Herein, broad-spectrum antibacterial and mechanically tunable amyloid-based hydrogels based on self-assembly and local mineralization of silver nanoparticles are reported. The mineralized hydrogels are biocompatible and have the advantages of sustained release of silver, prolonged antimicrobial effect, and improved adhesion capacity. Moreover, the mineralized hydrogels display a significant antimicrobial effect against both Gram-positive and Gram-negative bacteria in cells and mice by inducing membrane damage and reactive oxygen species toxicity in bacteria. In addition, the mineralized hydrogels can rapidly accelerate wound healing by the synergy between their antibacterial activity and intrinsic improvement for cell proliferation and migration. This study provides a modular approach to developing a multifunctional protein hydrogel platform based on biomolecule-coordinated self-assembly for a wide range of biomedical applications.

Symmetry Breaking of Self-Propelled Topological Defects in Thin-Film Active Chiral Nematics.

Active nematics represent a range of dense active matter systems which can engender spontaneous flows and self-propelled topological defects. Two-dimensional (2D) active nematic theory and simulation have been successful in explaining many quasi-2D experiments in which self-propelled +1/2 defects are observed to move along their symmetry axis. However, many active liquid crystals are essentially chiral nematic, but their twist mode becomes irrelevant under the 2D assumption. Here, we use theory and simulation to examine a three-dimensional active chiral nematic confined to a thin film, thus forming a quasi-2D system. We predict that the self-propelled +1/2 disclination in a curved thin film can break its mirror symmetry by moving circularly. Our prediction is confirmed by hydrodynamic simulations of thin spherical-shell and thin cylindrical-shell systems. In the spherical-shell confinement, the four emerged +1/2 disclinations exhibit rich dynamics as a function of activity and chirality. As such, we have proposed a new symmetry-breaking scenario in which self-propelled defects in quasi-2D active nematics can acquire an active angular velocity, greatly enriching their dynamics for finer control and emerging applications.

Repetition rate tuning and locking of solitons in a microrod resonator.

Recently, there has been significant interest in the generation of coherent temporal solitons in optical microresonators. In this Letter, we present a demonstration of dissipative Kerr soliton generation in a microrod resonator using an auxiliary-laser-assisted thermal response control method. In addition, we are able to control the repetition rate of the soliton over a range of 200 kHz while maintaining the pump laser frequency, by applying external stress tuning. Through the precise control of the PZT voltage, we achieve a stability level of 3.9 × 10-10 for residual fluctuation of the repetition rate when averaged 1 s. Our platform offers precise tuning and locking capabilities for the repetition frequency of coherent mode-locked combs in microresonators. This advancement holds great potential for applications in spectroscopy and precision measurements.

Synthesis of soybean soluble polysaccharide-based eco-friendly emulsions for soil erosion prevention and control.

This paper introduces the synthesis of an environmentally friendly emulsion that can be used as a soil anti-water erosion material. SSPS-g-P(BA-co-MMA-co-AA) emulsions were prepared using free radical copolymerization with soybean soluble polysaccharide (SSPS), acrylic acid (AA), butyl acrylate (BA), and methyl methacrylate (MMA). The structure, thermal stability, and morphology were characterized using FT-IR,TG,SEM, and particle diameter analysis. The resistance to water erosion, compressive strength and water retention of emulsion-treated loess/laterite was studied and germination tests were conducted. The results demonstrated that the duration of washout resistance of loess with 0.50 wt% emulsion exceeded 99 h, and the water erosion rate was 56.0 % after 72 h, while the water erosion rate of pure loess is 100.0 % after 4 min;the duration of washout resistance of laterite with 0.50 wt% emulsion exceeded 2 h, which was 8 times longer than pure laterite;The compressive strengths of 0.5 wt% emulsion-treated loess/laterite were 3.5 Mpa and 5.8 MPa, respectively, which were 7 and 9 times higher than that of pure soil. The plant seeds germinated normally half a month after planting. These findings suggest that emulsions can be used to control soil erosion without affecting the germination of plant seeds.

Fe-Zn alloy, a new biodegradable material capable of reducing ROS and inhibiting oxidative stress.

Fe-based biodegradable materials have attracted significant attention due to their exceptional mechanical properties and favorable biocompatibility. Currently, research on Fe-based materials mainly focuses on regulating the degradation rate. However, excessive release of Fe ions during material degradation will induce the generation of reactive oxygen species (ROS), leading to oxidative stress and ferroptosis. Therefore, the control of ROS release and the improvement of biocompatibility for Fe-based materials are very important. In this study, new Fe-Zn alloys were prepared by electrodeposition with the intention of using Zn as an antioxidant to reduce oxidative damage during alloy degradation. Initially, the impact of three potential degradation ions (Fe2+, Fe3+, Zn2+) from the Fe-Zn alloy on human endothelial cell (EC) activity and migration ability was investigated. Subsequently, cell adhesion, cell activity, ROS production and DNA damage were assessed at various locations surrounding the alloy. Finally, the influence of different concentrations of Zn2+ in the medium on cell viability and ROS production was evaluated. High levels of ROS exhibited evident toxic effects on ECs and promoted DNA damage. As an antioxidant, Zn2+ effectively reduced ROS production around Fe and improved the cell viability on its surface at a concentration of 0.04 mmol/l. These findings demonstrate that Fe-Zn alloy can attenuate the ROS generated from Fe degradation thereby enhancing cytocompatibility.

Crystal structure of HPPD inhibitor sensitive protein from Oryza sativa.

4-hydroxyphenylpyruvate dioxygenase (HPPD) Inhibitor Sensitive 1 (HIS1) is an endogenous gene of rice, conferring broad-spectrum resistance to ß-triketone herbicides. Similar genes, known as HIS1-like genes (HSLs), exhibit analogous functions and can complement the herbicide-resistant characteristics endowed by HIS1. The identification of HIS1 and HSLs represents a valuable asset, as the intentional pairing of herbicides with resistance genes emerges as an effective strategy for crop breeding. Encoded by HIS1 is a Fe(II)/2-oxoglutarate-dependent oxygenase responsible for detoxifying ß-triketone herbicides through hydroxylation. However, the precise structure supporting this function remains unclear. This work, which determined the crystal structure of HIS1, reveals a conserved core motif of Fe(II)/2-oxoglutarate-dependent oxygenase and pinpoints the crucial residue dictating substrate preference between HIS1 and HSL.

Which is the appropriate surgical procedure for appendiceal adenocarcinoma: appendectomy, partial colectomy or right hemicolectomy?

Objective The purpose of this study was to explore the appropriate surgical procedure and clinical decision for appendiceal adenocarcinoma. Methods A total of 1,984 appendiceal adenocarcinoma patients from 2004 to 2015 were retrospectively identified from the Surveillance, Epidemiology, and End Results (SEER) database. All patients were divided into three groups based on the extent of surgical resection: appendectomy (N = 335), partial colectomy (N = 390) and right hemicolectomy (N = 1,259). The clinicopathological features and survival outcomes of three groups were compared, and independent prognostic factors were assessed. Results The 5-year OS rates of patients who underwent appendectomy, partial colectomy and right hemicolectomy were 58.3%, 65.5% and 69.1%, respectively (right hemicolectomy vs appendectomy, P < 0.001; right hemicolectomy vs partial colectomy, P = 0.285; partial colectomy vs appendectomy, P = 0.045). The 5-year CSS rates of patients who underwent appendectomy, partial colectomy and right hemicolectomy were 73.2%, 77.0% and 78.7%, respectively (right hemicolectomy vs appendectomy, P = 0.046; right hemicolectomy vs partial colectomy, P = 0.545; partial colectomy vs appendectomy, P = 0.246). The subgroup analysis based on the pathological TNM stage indicated that there was no survival difference amongst three surgical procedures for stage I patients (5-year CSS rate: 90.8%, 93.9% and 98.1%, respectively). The prognosis of patients who underwent an appendectomy was poorer than that of those who underwent partial colectomy (5-year OS rate: 53.5% vs 67.1%, P = 0.005; 5-year CSS rate: 65.2% vs 78.7%, P = 0.003) or right hemicolectomy (5-year OS rate: 74.2% vs 53.23%, P < 0.001; 5-year CSS rate: 65.2% vs 82.5%, P < 0.001) for stage II disease. Right hemicolectomy did not show a survival advantage over partial colectomy for stage II (5-year CSS, P = 0.255) and stage III (5-year CSS, P = 0.846) appendiceal adenocarcinoma (AU)

Flow-induced periodic chiral structures in an achiral nematic liquid crystal.

Supramolecular chirality typically originates from either chiral molecular building blocks or external chiral stimuli. Generating chirality in achiral systems in the absence of a chiral input, however, is non-trivial and necessitates spontaneous mirror symmetry breaking. Achiral nematic lyotropic chromonic liquid crystals have been reported to break mirror symmetry under strong surface or geometric constraints. Here we describe a previously unrecognised mechanism for creating chiral structures by subjecting the material to a pressure-driven flow in a microfluidic cell. The chirality arises from a periodic double-twist configuration of the liquid crystal and manifests as a striking stripe pattern. We show that the mirror symmetry breaking is triggered at regions of flow-induced biaxial-splay configurations of the director field, which are unstable to small perturbations and evolve into lower energy structures. The simplicity of this unique pathway to mirror symmetry breaking can shed light on the requirements for forming macroscopic chiral structures.

Which is the appropriate surgical procedure for appendiceal adenocarcinoma: appendectomy, partial colectomy or right hemicolectomy?

OBJECTIVE: The purpose of this study was to explore the appropriate surgical procedure and clinical decision for appendiceal adenocarcinoma. METHODS: A total of 1,984 appendiceal adenocarcinoma patients from 2004 to 2015 were retrospectively identified from the Surveillance, Epidemiology, and End Results (SEER) database. All patients were divided into three groups based on the extent of surgical resection: appendectomy (N = 335), partial colectomy (N = 390) and right hemicolectomy (N = 1,259). The clinicopathological features and survival outcomes of three groups were compared, and independent prognostic factors were assessed. RESULTS: The 5-year OS rates of patients who underwent appendectomy, partial colectomy and right hemicolectomy were 58.3%, 65.5% and 69.1%, respectively (right hemicolectomy vs appendectomy, P < 0.001; right hemicolectomy vs partial colectomy, P = 0.285; partial colectomy vs appendectomy, P = 0.045). The 5-year CSS rates of patients who underwent appendectomy, partial colectomy and right hemicolectomy were 73.2%, 77.0% and 78.7%, respectively (right hemicolectomy vs appendectomy, P = 0.046; right hemicolectomy vs partial colectomy, P = 0.545; partial colectomy vs appendectomy, P = 0.246). The subgroup analysis based on the pathological TNM stage indicated that there was no survival difference amongst three surgical procedures for stage I patients (5-year CSS rate: 90.8%, 93.9% and 98.1%, respectively). The prognosis of patients who underwent an appendectomy was poorer than that of those who underwent partial colectomy (5-year OS rate: 53.5% vs 67.1%, P = 0.005; 5-year CSS rate: 65.2% vs 78.7%, P = 0.003) or right hemicolectomy (5-year OS rate: 74.2% vs 53.23%, P < 0.001; 5-year CSS rate: 65.2% vs 82.5%, P < 0.001) for stage II disease. Right hemicolectomy did not show a survival advantage over partial colectomy for stage II (5-year CSS, P = 0.255) and stage III (5-year CSS, P = 0.846) appendiceal adenocarcinoma. CONCLUSIONS: Right hemicolectomy may not always be necessary for appendiceal adenocarcinoma patients. An appendectomy could be sufficient for therapeutic effect of stage I patients, but limited for stage II patients. Right hemicolectomy was not superior to partial colectomy for advanced stage patients, suggesting omission of standard hemicolectomy might be feasible. However, adequate lymphadenectomy should be strongly recommended.

Metabolite characterisation of the peptide-drug conjugate LN005 in liver S9s by UHPLC-Orbitrap-HRMS.

LN005 is a peptide-drug conjugate (PDC) targeting glucose-regulated protein 78 (GRP78) to treat several types of cancer, such as breast, colon, and prostate cancer.As a new drug modality, understanding its metabolism and elimination pathways will help us to have a whole picture of it. Currently, there are no metabolic studies on LN005; therefore, this study aimed to investigate the metabolism of LN005, clarify its metabolic profile in the liver S9s of different species, and identify the major metabolic pathways and differences between species.The incubation samples were measured by ultra-high performance liquid chromatography combined with orbitrap tandem mass spectrometry (UHPLC-Orbitrap-HRMS).The results showed that LN005 was metabolised by liver S9s, and four metabolites were identified. The main metabolic pathway of LN005 in liver S9s was oxidative deamination to ketone or hydrolysis. Similar metabolic profiles were observed in mouse, rat, dog, monkey, and human liver S9s, indicating no differences between these four animal species and humans.This study provides information for the structural modification and optimisation of LN005 and affords a reference for subsequent animal experiments and human metabolism of other PDCs.

The Effects of VR-assisted and Overground Gait Adaptation Training on Balance and Walking Ability in Stroke Patients.

OBJECTIVE: This study compared the effects of virtual reality(VR)-assisted gait adaptation training with the overground gait adaptation training on balance and walking in patients with stroke. METHODS: Fifty-four eligible patients were enrolled. All patients were randomly divided into a VR and control group, with 27 patients in each group. The VR group received VR-assisted training on the treadmill, whereas the control group received overground training in a physical therapy room. After the intervention, patients were assessed using walking speed, obstacle avoidance ability, timed up and go (TUG) test, postural stability, and the Barthel Index (BI). RESULTS: Significant improvements in walking speed, obstacle avoidance ability, TUG test and eye-opening center of pressure (COP) speed were observed after the intervention (P < 0.05). No statistically significant differences were found in eye-closing COP speed, tandem COP speed, single-leg COP speed, and BI (P > 0.05). CONCLUSIONS: Stroke patients may benefit from VR-assisted gait adaptation training in improving walking and static balance function and reducing the risk of falls.

Molecular dynamics simulation of the interaction between palmitic acid and high pressure CO2.

In this study, molecular dynamics simulation was used to explore the interaction characteristics of palmitic acid and CO2, and the effects of temperature and pressure on the solubility of palmitic acid in CO2 were investigated. In the range of 293-353 K and 5-30 MPa, the snapshot of palmitic acid distribution in CO2 shows that the molecular chain of palmitic acid in high-density CO2 system is more straight and more dispersed than that in low-density CO2 system. The radial distribution function further clearly shows that the solubility of palmitic acid in CO2 decreases with the increase of temperature and increases with the increase of pressure, which is consistent with the fatty acid solubility data reported in the literature and the setting rules of supercritical CO2 extraction process conditions. As the temperature decreases and the pressure increases, the interaction energy between palmitic acid and CO2 increases, which is conducive to overcoming the intermolecular force of palmitic acid and promoting dissolution. The solubility parameters of palmitic acid and CO2 can better reflect the trend of palmitic acid solubility changing with temperature and pressure, which can play a guiding role in the determination of process conditions and even the development of new processes.

Crystal structure of an aspartate aminotransferase Lpg0070 from Legionella pneumophila.

Legionella pneumophila aspartate aminotransferase (Lpg0070) is a member of the transaminase and belongs to the pyridoxal 5'-phosphate (PLP)-dependent superfamily. It is responsible for the transfer of α-amino between aspartate and α-ketoglutarate to form glutamate and oxaloacetate. Here, we report the crystal structure of Lpg0070 at the resolution of 2.14 Å and 1.7 Å, in apo-form and PLP-bound, respectively. Our structural analysis revealed the specific residues involved in the PLP binding and free form against PLP-bound supported conformational changes before substrate recognition. In vitro enzyme activity proves that the absence of the N-terminal arm reduces the enzyme activity of Lpg0070. These data provide further evidence to support the N-terminal arm plays a crucial role in catalytic activity.

Hybrid integrated narrow-linewidth semiconductor lasers.

Integrated narrow-linewidth lasers are the key devices in compact coherent optical systems of metrology, sensing, and optical microwave generation. Here, we demonstrate a hybrid integrated laser based on an optical negative feedback scheme. The laser is composed of a commercial distributed feedback (DFB) laser diode and an on-chip micro-resonator with a Q-factor of 0.815 million. The feedback optical field is coupled back to the laser cavity through the back facet. Therefore, the laser can maintain the lasing efficiency of the DFB laser diode. The linewidth of the DFB laser diode is compressed from 2 MHz to 6 kHz, corresponding to the linewidth reduction factor of 25.2 dB. The theoretical result shows that the laser performance still has a huge improvement margin through precise control of the detuning between laser frequency and the micro-resonator, as well as the phase delay of the feedback optical field. The hybrid narrow-linewidth laser diode has wide application prospects in coherent optical systems benefitting from the low cost and volume productivity.