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Under ultraviolet (UV) excitation with photon energy larger than 4.5 eV, a charge-state conversion from negatively to neutrally charged nitrogen-vacancy (NV− to NV0) centers in diamond samples is realized. The UV-induced charge-state conversion is found to strongly depend on the N concentration in the sample and the irradiation fluence of the electron beam. For the samples with high N concentrations, low-fluence (2.5 × 1017 cm−2) 10-MeV electron beam irradiation usually leads to UV-induced charge-state conversion efficiency higher than that of the samples irradiated with high fluences (≥2.5 × 1018 cm−2). For the samples with a few ppm N, however, the charge-state conversion efficiency is relatively low in the cases of irradiation fluences in this work. Meanwhile, UV-induced NV0 luminescence exhibits temperature dependence different from that of visible-light excited NV0 or NV− centers; that is, the photoluminescence intensity does not reach saturation at temperatures lower than 135 K but decreases with the decrease in temperature. Based on the photoluminescence excitation spectra of NV0 centers in the UV region, the UV-induced charge-state conversion is suggested to involve free-hole generation, diffusion, and the capture by ground-state NV− centers. [ABSTRACT FROM AUTHOR]

The hollow slender shaft is characterized by intricate component features such as a significant depth-to-diameter ratio, variable cross-sections, and non-uniform thin walls. Uneven deformation of the hollow slender shaft during deformation results in degradation of service performance. In this study, the deformation uniformity is explored from a microscopic point of view, the numerical simulation model of dynamic recrystallization of 6061 aluminum alloy is established with the DEFORM-3D software. And grain evolution during the aluminum alloy extrusion process was theoretically analyzed using the cellular automata. [ABSTRACT FROM AUTHOR]

Personalized incentive-based strategies that aim at encouraging commuters to shift their travel modes to public transit modes have long been supposed to release road congestion and promote green travel. However, previous studies didn't explore the heterogeneity of how incentives change commuters' travel mode choice in different cities or their sensitivity to different types of incentives. To address this gap, we propose a two-stage analysis framework to categorize cities based on the willingness of commuters in different cities to change their travel modes and further analyze the differences in commuters' sensitivity to various types of incentives. The results indicate that the perceived value of commuters for the same incentives in different categories of cities is remarkably different. The willingness of commuters to use public transit modes after the implementation of incentives is not significantly correlated to the level of economic development of cities. These results could generate significant implications for formulating differentiated and personalized incentives to increase the commuters' willingness to travel by public transitmodes in different types of cities. [ABSTRACT FROM AUTHOR]

In this study, a time-dependent expansion model of mudstone based on the rheological theory is developed. The model is validated with the results of the free expansion test of mudstone under lateral limits. We have explained the physical significance of all the parameters in the model. The ultimate strain of the mudstone flooding expansion is determined by the swelling force and progressive expansion elastic modulus. The expansion model can be used to describe and predict the time-dependent expansion of the mudstone submerged under water. The time-dependent expansion model is introduced to generalize the Einstein's three-dimensional static stable constitutive relation to a nonstable dynamic three-dimensional constitutive relation. [ABSTRACT FROM AUTHOR]

To evaluate the quantitative parameters derived from synthetic magnetic resonance imaging (SyMRI) for predicting triple-negative breast cancer (TNBC). This prospective study enrolled participants with invasive ductal breast carcinoma (IDBC) and separated them into a TNBC group and a Non-TNBC group. Preoperative breast MRI included both the SyMRI and conventional MRI sequences. The quantitative parameters derived from the SyMRI included T1 and T2 relaxation times, proton density (PD), and their standard deviations (SD). Clinicopathological characteristics, conventional MRI findings, and quantitative synthetic parameters were assessed for all participants. Multivariable logistic regression analysis was performed to determine the potential independent imaging predictors for TNBC preoperatively. Receiver operating characteristic (ROC) curve analysis was used to evaluate the performance of these parameters. A total of 231 participants with histopathological proven IDBC were included in this study (n= 46 in the TNBC group and n= 185 in the Non-TNBC group). The TNBC group had significantly larger tumour size (p =0.011) and more frequent intratumoural cystic or necrotic lesions (p <0.001) as compared to the Non-TNBC group. The univariate analysis showed that the TNBC tumours had significantly higher T1 (p= 0.006) and T2 (p <0.001) values than Non-TNBC tumours. Subsequent multivariable analysis indicated that T2 values and the presence of cystic or necrotic lesions were the independent predictors for TNBC. The T2 from synthetic imaging and the presence of cystic degeneration or necrosis within the breast cancer may serve as potential imaging biomarkers for preoperative differentiation of TNBC from Non-TNBC. • Quantitative parameters derived from synthetic MRI is associated with TNBC. • T2 obtained from synthetic imaging was independent predictor for identifying TNBC. • Imaging biomarkers provide great help in diagnosis of TNBC prior to surgery. [ABSTRACT FROM AUTHOR]

Abstract Orychophragmus violaceus (OV) and chicory (Cichorium intybus L., CC) can be used as fresh or dry forage for animals. To determine whether OV and/or CC have beneficial effects on performance and egg quality, a total of 1212 28-wk-old Beijing You Chicken (BYC) laying hens with similar performance were randomly allocated to 4 groups with 3 replicate pens per group, and 101 birds per pen. The birds were fed a basal diet (control), the basal diet + OV (3.507 kg/d/pen), the basal diet + CC (2.525 kg/d/pen), and the basal diet + OV + CC (OVC, 1.7535 kg/d/pen OV + 1.2625 kg/d/pen CC) for 3 wks after one wk of adaptation. The results showed that egg-laying rate was not affected by OV, CC and OVC (p > 0.05), but weekly average egg mass was significantly increased by OV and CC (p < 0.05). The feed egg ratio in the CC group (2.82) was significantly lower than that in the other three groups (p < 0.05). The eggshell thickness (EST), albumen height (AH) and Haugh unit (HU) were decreased by OV and CC (p < 0.05); while yolk color (YC) was increased in the CC and OVC groups (p < 0.05). Egg grade was decreased by OV (p < 0.05). Sensory evaluation showed that there was a trend for increased YC in OV, CC and OVC (p = 0.089). Serum total protein was significantly lower in OV group than those in the control and CC group (p < 0.05); serum albumin content was significantly decreased in OV, CC and OVC groups (p = 0.006). Serum glutathione peroxidase activity in CC and OVC groups was significantly higher than that in the control group (p < 0.05). In conclusion, the present study suggests that CC had a better effect on the performance of the native laying hens than OV. The OV and CC affected egg quality, while YC was increased in CC and OVC groups. The OVC improved YC and serum antioxidative properties of native laying hens without affecting the performance. [ABSTRACT FROM AUTHOR]

In this paper, we have explored the local structure and fractal characteristics of fractal functions with certain fractal dimensions. The conclusion that points with inconsistent oscillation amplitudes with the upper Box dimension of the corresponding fractal functions have been proved to be nowhere dense. This will play an important supporting role in exploring the fractal dimension estimation of the combination of fractal functions. [ABSTRACT FROM AUTHOR]

Dry reforming of methane is a very appealing catalytic route biogas (mainly composed by greenhouse gases: carbon dioxide and methane) conversion into added value syngas, which could be further upgraded to produce liquid fuels and added value chemicals. However, the major culprits of this reaction are coking and active phase sintering that result in catalysts deactivation. Herein we have developed a highly stable bimetallic Ni–Rh catalyst supported on mixed CeO 2 –Al 2 O 3 oxide using low-noble metal loadings. The addition of small amounts of rhodium to nickel catalysts prevents coke formation and improves sintering resistance, achieving high conversions over extended reaction times hence resulting in promising catalysts for biogas upgrading. [Display omitted] • H 2 -rich syngas can be obtained efficiently from biogas reforming. • Ni-based catalysts are deactivated by metal sintering and coke deposition. • Doping with low Rh loadings deactivation can be successfully prevented. [ABSTRACT FROM AUTHOR]

Previous studies revealed that tooth loss or edentulism was related to mortality. However, research in developing countries with large numbers of elderly populations is rare, and whether sex differences exist in this relationship is unknown. This study aimed to investigate the association between edentulism and 7-year all-cause mortality among older adults in China and whether sex differences existed. This was a prospective cohort study. Data were from 2011 to 2018 waves of the China Health and Retirement Longitudinal Study. A total of 6538 participants aged ≥60 years were included. Logistic models were adopted to estimate the risks of mortality according to edentulism. The participants with edentulism at baseline were 20% more likely to die over 7 years after controlling for a set of covariates (odds ratio [OR] = 1.20, 95% confidence interval [CI]: 1.02–1.42). Moreover, edentulism was associated with a 35% higher odds of death among male participants (OR = 1.35, 95% CI: 1.08–1.70), whereas a significant association was not found in female participants. The findings demonstrated that baseline edentulism predicted all-cause mortality in Chinese older adults, and sex differences existed in this association. This study implied the importance of developing oral health education programs, incorporating dietary recommendations into dental care for edentulous patients, and expanding the coverage of dental services in the health insurance system to prevent edentulism and alleviate its negative outcomes for older adults. [ABSTRACT FROM AUTHOR]

A large number of experiments were performed to systematically investigate the evolution of the acoustic emission characteristics, dynamic elastic modulus, and axial residual strain of rock under different cyclic loading paths. These results provide experimental support for the damage accumulation and fatigue/failure characteristics of rock structures, and for the construction of a new nonlinear fatigue cumulative damage model suitable for rock materials. More active acoustic emissions are associated with greater acoustic emission intensity, which reflects the association between the dynamic elastic modulus and greater damage. Under increasing cyclic loading, the axial residual strain increases stepwise with increasing load level, following a nonlinear function. Under decreasing cyclic loading, the axial residual strain decreased stepwise and nonlinearly with decreasing load level. [ABSTRACT FROM AUTHOR]

The effect of tuning the depolarization field in (001)-oriented ultrathin epitaxial PbZr0.4Ti0.6O3/SrTiO3/PbZr0.4Ti0.6O3 ferroelectric heterostructures is investigated. The thickness of the dielectric spacer (SrTiO3) is maintained constant at 2 unit cells. The ferroelectric layer thickness in the heterostructure (each PbZr0.4Ti0.6O3) layer varied from 8 to 15 nm is exploited as the parameter to tune the depolarization field. Piezoresponse force microscopy reveals a domain evolution from continuous labyrinthine domains to individual nanoscale bubble domains under the influence of an increasing depolarization field. A statistical analysis of the domain features (i.e., domain wall length and domain fraction) reveals that this change in domain morphology also affects the wall roughness and its associated disorder. The local coercive voltage obtained using switching spectroscopy piezoresponse force microscopy finds the 15 nm film to have the lowest coercive voltage. This is attributed to both a strain-induced increase in tetragonality and the depolarization field-induced changes in the domain morphology. [ABSTRACT FROM AUTHOR]

We define and investigate a class of partial orders, called one-sided w -core partial orders, extending the recently introduced w -core partial order. We give several characterizations. In particular, it is shown that a is below b under the left w -core partial order (resp., right w -core partial order) if and only if a is below b under the left star partial order (resp., wa is below wb under the right sharp partial order, provided that w is invertible). Also, the relationship with several well-known other partial orders is considered. [ABSTRACT FROM AUTHOR]

In hydroponic conditions, we investigated the effects of applied magnesium (Mg) on quality of leaf and aroma of seedlings of Wuyi Rougui tea (Camellia sinensis L.). Different concentrations of Mg [0.4 mM (Mg¹), 0.6 mM (Mg²) and 0.8 mM (Mg³)] were added into the hydroponic solution. Control treatment did not contain Mg (Mg0). With the increasing availability of Mg, the polyphenols content were significantly increased. The lowest free amino acid content (2.44 %) was observed in the Mg¹ treatment. The Mg treatments significantly influenced the caffeine level, except in Mg² and Mg³. Maximum total flavone content (9.30 mg/g) was in Mg² treatment followed by Mg¹, Mg³ and Mg0, respectively. The highest content of soluble sugars (9.30 %) was observed in the Mg² treatment followed by Mg¹, Mg³ and Mg0. Principal component analyses of quality indicators showed that PCoA1 and PCoA2 differed in samples treated with various Mg concentrations and the total variability was 97.73 %. Caffeine and catechin contents showed a negative correlation to increasing Mg concentrations. The last ones displayed a positive correlation (r = 0.945) with (E,E)-2,4-heptadienal levels and were inversely correlated (r = - 0.967) with decanal content. [ABSTRACT FROM AUTHOR]

Cauliflower is one of the most important popular vegetables in China. Cauliflower (Brassica oleracea L. var. botrytis) produces glucosinolates, which are secondary metabolites that have anti-cancer properties. The choice of suitable reference genes (RGs) for gene expression studies has a significant effect on experimental outcomes. In this study, we selected 15 candidates as RGs and analyzed them under heat, cold, drought, and salt stresses and methyl jasmonate (MeJA) treatment. The precision of the real-time quantitative polymerase chain reaction data was assessed using four methods (geNorm, NormFinder, BestKeeper, and ΔCt). The results revealed that EF1-ß and ACT7; ACT1, EF1-ß, and TUB6; TUA2 and EF1-ß; HIS and ACT7; and ACT7 and ACT3 were the most stable combinations of genes for heat stress, cold stress, drought stress, salt stress, and MeJA treatment, respectively. The expression stability of the RGs fluctuated under different experimental conditions. Choosing the optimal RG for the specific experiment is therefore essential. This work provides relevant information for further gene expression studies on cauliflower and other closely related species. [ABSTRACT FROM AUTHOR]

The density, crystallinity, and microstructure of reactively sputtered amorphous Ge2Sb2Te5 thin films have been assessed as a function of deposition temperature. The continuous density increase was observed with increasing substrate temperature between room temperature and 200 °C. The films deposited at room temperature are amorphous and exhibit a columnar structure with a lateral size of cells in the 10–15 nm range. Cells consist of high-density interior with boundaries with the density lower by ∼9% due to incorporation of pores. The pores and the columnar microstructure can be eliminated by deposition at 80 °C while still preserving the amorphous phase. The density of pore- and stress-free amorphous Ge2Sb2Te5 is 6.16 g/cm3 and is only 1.5% lower than the crystalline Ge2Sb2Te5 with NaCl structure. [ABSTRACT FROM AUTHOR]

Using first-principle calculations, we investigate the electronic and magnetic properties of Li-adsorbed T-CrTe2 monolayer. We demonstrate that Li adsorption turns the electronic properties mainly through electron doping and lattice expansion. As the adsorption concentration increases from 3.7% to 33.3%, the magnetic moment of Cr increases from 2.25 to 2.98μB linearly. More interesting, the T-CrTe2 monolayer becomes ferromagnetic semiconductors with indirect band gaps under the tensile strain. While a tensile strain is applied, a transformation from metal to half-metal has been found. Our work provides an efficient strategy to seek magnetism and produce two-dimensional magnetic semiconductors and half-metals from metals. [ABSTRACT FROM AUTHOR]

Indentation tests at various depths confirm that the scale factor, f, which was proposed to modify the Nix-Gao model, is governed only by intrinsic properties of materials, but the connection between f and intrinsic properties is still unknown. From this, a connection is established between f and pertinent parameters, such as activation volume, V, and theoretical strength, G. Moreover, considering the interaction between adjacent indentations, we define a critical scale factor feff to describe the strengthening interface, which is found proportional to indentation depth for the given material. It is also found that larger feff is preferred for high-strength high-entropy alloys and/or medium-entropy alloys than pure metals. Combining f and feff of Ni, CoNi, CoCrNi and FeCoCrNi metals and alloys, a model describing dislocation density distribution in indentation plastic zone is established, in which the plastic zone includes three parts, i.e., the indentation zone of equivalent conical indenter, the detectable dislocation enhancement region, and the low dislocation density region. The inconsonant trends of f and feff can be explained by the existing of dislocation saturation zone in the plastic zone. The gradient plastic zone model proposed here graphically depicts the dislocations motion, as well as its reinforcement effect. Furthermore, this model lends credence to modify the framework which describes the mechanical response of materials under nanoindentation. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is an age-related neurodegenerative disorder. Neuritic plaques containing amyloid-β protein (Aβ) and neurofibrillary tangles composed of hyperphosphorylated tau protein constitute major neuropathological hallmarks of AD. The neurotoxicity of aggregated Aβ has been implicated as a critical cause in the pathogenesis of AD. The aim of this study was to exam the use of neoagarohexaose (NAH) in the potential treatment of AD effects, using SH-SY5Y neuronal cell line exposed to β-amyloid protein (Aβ1-42). The present study was designed to explore the neuroprotective effects of NAH on neuroblastoma SH-SY5Y cells as a function of dosage. The cells were exposed to Aβ1-42 with or without NAH (26.7, 53.4, and 106.8 μM) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used for detecting the viability of treated cells. In treated cells, the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) were determined using their manufacturer kits. Flow cytometry analysis was used to assess apoptosis, changes in intracellular calcium concentration, and the mitochondrial membrane potential (MMP) after treatment. Additionally, changes in the mechanism of Aβ1-42 aggregation in the presence of NAH were explored using thioflavin T (ThT) and Congo red (CR) assays. The results showed that incubation with NAH prior to Aβ1-42 exposure increased cell survival and prevented reactive oxygen species generation. Moreover, NAH decreased the apoptotic rate, inhibited MMP depolarization, reversed the change in intracellular calcium concentration, enhanced the activities of SOD and GSH-Px, and decreased the level of MDA. In addition, the results showed that NAH, which reduced the absorption of the amyloid indicator ThT and CR dyes, was a potent inhibitor of Aβ fibrillogenesis. In conclusion, NAH protects SH-SH5Y cells from Aβ-induced damage by reducing oxidative stress and weakens the spontaneous amyloid formation of Aβ fibrils in vitro and can inhibit the amyloidization of amyloid β protein (Aβ). This study shows that NAH may be a promising anti-AD drug candidate for AD treatment. [ABSTRACT FROM AUTHOR]

Combining deep machine learning with silver nanoparticle (Ag NP)-based surface-enhanced Raman spectroscopy (SERS), we have developed a novel method for whole blood analysis for cancer detection applications. The whole blood was collected from two groups: one group of patients (n = 26) with lung cancer and another group of healthy volunteers (n = 45). The logistic regression (LR), k-nearest neighbor (KNN), decision tree (DT), and random forest (RF) algorithms were employed to develop a diagnostic model using the same spectral data. The results show that the diagnostic accuracy of LR, KNN, DT, and RF models was 87, 66, 77, and 83%, respectively. LR is superior to other algorithms in the SERS spectra classification of whole blood. We therefore believe that this proposed strategy will have great clinical potential for SERS technology combined with LR and act as a complementary method for the detection of lung cancer. [ABSTRACT FROM AUTHOR]

In this study, polycrystalline SnSe was synthesized via a rapid, cost-effective, and large-scale synthesis route. The obtained SnSe powders were pressed into pellets via spark plasma sintering (SPS) at different temperatures. Powder X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM) were used to characterize the crystal structures and morphology of the SnSe samples. The XRD results indicate that the orientation factors increase monotonously with the increase of sintering temperature. The FESEM images show that sintering temperatures have no obvious influence on the particle size. Positron annihilation measurements indicate that vacancy defects exist in all the sintered SnSe samples, and they recover gradually with increasing sintering temperatures. These vacancy defects are responsible for the lower lattice thermal conductivity in samples sintered at lower temperatures. The electrical conductivity, power factor, thermal conductivity, and figure of merit ZT show nearly the same variation trend, which increases initially with the increasing sintering temperature up to 550 ° C then decreases with further increase of the sintering temperature, which is possibly due to slight oxidation of SnSe. A maximum ZT value of ∼ 0.47 at 430 ° C was achieved for the 550 ° C sintered sample, which is higher than those reported for undoped polycrystalline SnSe around this temperature. Thus, we provide a simple, energy-saving, and effective method to synthesize polycrystalline SnSe in large quantities, and SPS is an effective method to optimize thermoelectric performance. [ABSTRACT FROM AUTHOR]

Calcium plays an essential role in plant developmental process, especially in pollen tube growth. Verapamil, an inhibitor of calcium channels, could affect extracellular calcium ion influx. The present study aimed to investigate the effect of verapamil on pollen tube growth of Malus domestica and the possible cytological mechanism. Results showed that verapamil affected pollen germination and tube growth in a dose dependent manner. 20 μM verapamil promoted pollen germination and tube growth, while 700 μM verapamil inhibited pollen germination and tube growth. Results from non-invasive ion-selective electrode technique and fluorescent labeling showed that 700 μM verapamil decreased calcium influx and disturbed [Ca2+]c gradient at pollen tube apex. In addition, 700 μM verapamil also affected actin filaments. Further results demonstrated that 700 μM verapamil influenced distribution of pollen tube wall components such as callose, acid pectins and esterified pectins, Fourier-transform infrared analysis (FTIR) of chemical composition supported the above results. In summary, 700 μM verapamil triggered multiple cellular changes including Ca2+ influx, [Ca2+]c gradient, actin filaments and pollen tube wall components. Based on the above results, we speculated that 700 μM verapamil inhibited apical growth of pollen tubes through altering Ca2+ influx, [Ca2+]c gradient, actin filaments and cell wall components. [ABSTRACT FROM AUTHOR]

The tensile strength and ductility of face-centered cubic (FCC) multi-principal element alloys (MPEAs) typically decline monotonically with increasing temperature. In this work, we conducted tensile tests at different temperatures and characterized deformation microstructures for a nonequiatomic CoCrNi alloy with low stacking fault energy (SFE). Exceptional ductility is obtained at medium temperature, breaking the general sense of monotonic change with temperature. The effect of deformation mechanisms of dislocations, stacking faults and phase transformation on the ductility was discussed. This work reveals the unique temperature effect on the mechanical properties of metals with very low SFE. [ABSTRACT FROM AUTHOR]

Discrete models provide advantages in simulating fracture in quasi-brittle materials due, in part, to their simplicity in representing cracking and other forms of displacement discontinuity. However, the stress analyses that form the basis for fracture simulation are complicated by difficulties in modeling the Poisson effect and other aspects of elastic behavior. The capabilities of Voronoi-cell lattice models, which are a form of particle-based lattice model, for elastic stress analysis are evaluated. It is found that the conventional means for representing the Poisson effect in particle-based lattice models result in spatially correlated stress oscillations that, at first glance, mimic the effects of material heterogeneity. The correlation length is dependent on discretization size. Alternatively, material heterogeneity can be introduced into elastically uniform lattice models via random assignments of material properties, independent of mesh size and geometry. • Discrete mechanical models exhibit notional heterogeneity when loaded. • The notional heterogeneity is dependent on mean element size. • This heterogeneity is eliminated to produce elastically uniform systems. • Spatially correlated distributions of stiffness are imposed on the elastically uniform systems. • The heterogeneity can then be controlled independently of the underlying discretization. [ABSTRACT FROM AUTHOR]

In this paper, the enthalpy change of 1035 steel during phase transformation at different cooling rates was measured by differential scanning calorimetry (DSC). The activation energy of the phase transformation process was calculated by the equal conversion method, and the mechanism function of the process was also determined. The results shown that the value of the activation energy of phase transformation process varied with the transformation fraction, and the mechanism functions of transformation process are different in different temperature ranges, which are -ln(1-a)1/3 for = 645 °C -ln(1-a)1/2 for 660-655 °C and -ln(1-a) for 650-645 °C respectively. [ABSTRACT FROM AUTHOR]

Aims. This paper aims to track the three-dimensional (3D) evolution of a full halo coronal mass ejection (CME) on 2011 June 21. Methods. The CME results from a nonradial eruption of a filament-carrying flux rope in NOAA active region 11236. The eruption was observed in extreme-ultraviolet (EUV) wavelengths by the extreme-ultraviolet imager (EUVI) on board the ahead and behind Solar TErrestrial RElations Observatory (STEREO) spacecrafts and the atmospheric imaging assembly (AIA) on board the solar dynamics observatory (SDO). The CME was observed by the COR1 coronagraph on board STEREO and the C2 coronagraph on board the large angle spectroscopic coronagraph (LASCO). The revised cone model was slightly modified, with the top of the cone becoming a sphere, which is internally tangent to the legs. Using the multipoint observations, the cone model was applied to derive the morphological and kinematic properties of the CME. Results. The cone shape fits nicely with the CME observed by EUVI and COR1 on board the STEREO twin spacecraft and LASCO/C2 coronagraph. The cone angle increases sharply from 54° to 130° in the initial phase, indicating a rapid expansion. A relation between the cone angle and the heliocentric distance of the CME leading front is derived, ω = 130° −480d−5, where d is in units of R⊙. The inclination angle decreases gradually from ∼51° to ∼18°, suggesting a trend of radial propagation. The heliocentric distance increases gradually in the initial phase and quickly in the later phase up to ∼11 R⊙. The true speed of the CME reaches ∼1140 km s−1, which is ∼1.6 times higher than the apparent speed in the LASCO/C2 field of view. Conclusions. The revised cone model is promising in tracking the complete evolution of CMEs. [ABSTRACT FROM AUTHOR]

In this paper, we conduct an experimental study on the cavity evolution behind a hydrophobic sphere entering the water. It is found that there is a correlation between splash and cavity evolution. Two dominant regimes for cavity pinch-off, including hydrostatic pressure and pressure pulsation inside cavity, are confirmed. When the splash is removed by a guard, the cavity pinch-off is dominated by hydrostatic pressure. The theoretical model is well consistent with the experimental results, including the cavity profile and the dimensionless pinch-off depth. However, when the splash domes, the theoretical solution fails with the increase in the effect of pressure pulsation inside the closed cavity. With the increase in the Froude number Fr, the splash closure most significantly impacts the necking position. The impact of the splash closure is dependent of Fr, and there is a critical value of Frcri separating the deep pinch-off into two regimes. The critical value of Frcri = 134 is theoretically proposed, which is a reasonable predication for the present experimental observations. In addition, the expansion rate of cavity volume is measured to confirm the transition of distinct regimes. Based on our theoretical analysis, the critical expansion rate is determined as 4.9, which agrees well with present experimental result 4.6. Distinct pinch-off regimes significantly impact the subsequent cavity evolution and the forces on sphere. A deep seal controlled by hydrostatic pressure is constantly accompanied by severe cavity resonance and a dramatic decrease in the cavity length, whereas pinch-off controlled by pressure pulsation leads to weak ripples. [ABSTRACT FROM AUTHOR]

Background: Yak as a unique domestic animal that has extremely important social value and influence on the local culture and economy in the Qinghai-Tibet Plateau. The current study aimed to evaluate the genotype distribution of a series of economic traits (growth, meat quality and lactation) related to single nucleotide polymorphisms (SNP) in three Tibetan yak populations. Methods: A total of 238 yaks from three populations [Sibu (SB), Chawula (CWL) and Jiali (JL) yaks] including 34 SB, 104 JL and 100 CWL yak individuals were collected. All samples were genotyped for 12 SNP markers by using SNaPshot technology. Result: All loci had abundant polymorphisms in the three populations, except for the Hesx1_G618C locus. The dominant growth- related genotype was MyoD1_C1710T (C/T), which had the highest frequency in the three Tibetan yak populations. However, the growth-related dominant genotypes at UCP2_T1499C (C/T) and CYP4A11_G4806A (G/A) loci were rare genotypes in the three Tibetan yak populations. Results of Hardy-Weinberg equilibrium (HWE) analysis showed that all sites did not deviate from the HWE within the population. This finding indicated that these populations belonged to a natural one without having been subjected to artificial selection on economic traits. Overall, this study provided valuable reference for the future molecular breeding of yak based on the genotype distribution of economic-trait candidate markers in three yak populations in Tibet. [ABSTRACT FROM AUTHOR]

A potential iron phosphate (FePO4) catalyst was prepared using a low-temperature solid-state method for the heterogeneous Fenton-like degradation of methyl blue (MB). A variety of parameters affecting the MB removal rate, including temperature, initial pH, catalyst usage, H2O2 and MB concentration, was studied in detail. The prepared FePO4 exhibited a highly efficient catalytic reaction with seven cycle performance. In addition, a free radical masking experiment revealed the existence of a hydroxyl radical (•OH) and indicated that the degradation of MB was mainly due to the oxidation caused by •OH. This work suggests FePO4 is an efficient material, which is responsible for the catalytic degradation of the azo dye MB through a heterogeneous Fenton-like system. [ABSTRACT FROM AUTHOR]

We screened the fermentation broth of fungi from the rhizosphere soil of passion fruit (Passiflora edulis Sims.) for their herbicidal potential in bioassays and Pot culture. The potent herbicidal compounds of the fungi fermentation broth were evaluated by bioassay and pot test. The candidate substances in the fungi fermentation broth were analysed and identified. Nine fungi (No. 1, 2, 3, 4, 5, 6, 7, 8 and 9) were isolated from the rhizosphere soil of passion fruit using the plate dilution coating method. In Petriplate Bioassay, the fermentation broth of newly identified fungus Aspergillus sydowi 'FJFAFU01' drastically inhibited the growth of lettuce (Lactuca sativa) and barnyard grass (Echinochloa crus-galli). In Pot Culture, 50-times diluted fermentation broth inhibited the barnyard grass height by 42.73%. The HPLC and GC-MS analysis showed that the fermentation broth contained higher contents of nitrogenous compounds and oxygen compounds, including phenolic acids, terpenoids, flavonoids and alkaloids. The Aspergillus sydowi FJFAFU01 screened from the rhizosphere soil of passion fruit contained phenolic acids, terpenoids, flavonoids and alkaloids, these inhibited the growth of barnyard grass. Thus Aspergillus sydowi 'FJFAFU01' may be developed as potential mycoherbicide. [ABSTRACT FROM AUTHOR]

The hydrogen absorption–desorption characteristics of layered R3MgNi14 (R = Nd, Gd and Er) compounds have been investigated in this work, in order to understand the effect of atomic size on hydrogen storage properties. Although they have polymorphic 2H and 3R phases, the unit parameters (a and c/N) and average unit volumes are similar for the same rare earth atom, which decrease as the atomic size decrease from Nd to Gd and Er. Additionally, the cycle stabilities also decrease from Nd3MgNi14 to Gd3MgNi14 and Er3MgNi14 because the proper interstitial hole sizes. [ABSTRACT FROM AUTHOR]

We investigate the transverse coronal-loop oscillations induced by the eruption of a prominence-carrying flux rope on 7 December 2012. The flux rope, originating from NOAA Active Region (AR) 11621, was observed in extreme-ultraviolet (EUV) wavelengths by the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO) spacecraft and in the H α line center by the ground-based telescope at the Big Bear Solar Observatory (BBSO). The early evolution of the flux rope is divided into two steps: a slow-rise phase at a speed of ≈ 230 km s−1 and a fast-rise phase at a speed of ≈ 706 km s−1. The eruption generates a C5.8 flare and the onset of the fast rise is consistent with the hard X-ray (HXR) peak time of the flare. The embedded prominence has a lower speed of ≈ 452 km s−1. The eruption is significantly inclined from the local solar normal by ≈ 60∘, suggesting a typical non-radial eruption. During the early eruption of the flux rope, the nearby coronal loops are disturbed and experience independent kink-mode oscillations in the horizontal and vertical directions. The oscillation in the horizontal direction has an initial amplitude of ≈ 3.1 Mm, a period of ≈ 294 seconds, and a damping time of ≈ 645 seconds. It is most striking in 171 Å and lasts for three to four cycles. The oscillations in the vertical directions are observed mainly in 171, 193, and 211 Å. The initial amplitudes are in the range of 3.4 – 5.2 Mm, with an average value of 4.5 Mm. The periods are between 407 seconds and 441 seconds, with an average value of 423 seconds. The oscillations are damping and last for nearly four cycles. The damping times are in the range of 570 – 1012 seconds, with an average value of 741 seconds. Assuming a semi-circular shape of the vertically oscillating loops, we calculate the loop lengths according to their heights. Using the observed periods, we carry out coronal seismology and estimate the internal Alfvén speeds (988 – 1145 km s−1) and the magnetic-field strengths (12 – 43 G) of the oscillating loops. [ABSTRACT FROM AUTHOR]

V-Ti-based refractory high entropy alloys (RHEAs), e.g., VTiTa and VTiTaNb, have been found with outstanding mechanical properties and irradiation resistance, granting them application potential in nuclear engineering. Nonetheless, similar to conventional V-Ti-based alloys such as V-4Ti-4Cr, these alloys are sensitive to C/N/O interstitial impurities. Under irradiation, such impurities may promote the formation of precipitates which may affect the defect evolution, especially at the appearance of helium. Previous studies have observed different helium behavior in the above alloys, including the heterogeneous distribution of helium bubbles in VTiTa, but the origin was not clear. In this work, detailed microstructural characterization is performed to analyze the irradiation induced precipitates and their impact on helium bubble formation in these alloys. Under helium ion irradiation at 700°C, the TiN precipitates with the NaCl-type structure are formed in all the three alloys. Nonetheless, the interfaces between precipitates and matrix in VTiTa and VTiTaNb are semi-coherent while those in V-4Ti-4Cr are coherent, due to the various lattice parameters of the alloys. Moreover, severe lattice distortion is also found inside the precipitates in the two RHEAs. Consequently, significant heterogeneous nucleation of He bubbles is observed in these two RHEAs but not in V-4Ti-4Cr. Among the three alloys, the growth of precipitates is the fastest in VTiTa, causing the formation of bubble clusters. Furthermore, the growth direction as well as the shape of precipitates affects the shape of bubbles, leading to the {001} cuboids shape in V-4Ti-4Cr and the truncated {110} dodecahedra shape in V-Ti-Ta and V-Ti-Ta-Nb. [ABSTRACT FROM AUTHOR]

Osmium (Os) is a hexagonal-close-packed metal with a non-spherical Fermi surface that seriously deviates from the assumption in the Mayadas-Shatzkes electrical-resistivity model (MS model) for the size effects of polycrystalline films of metals due to electron scattering by grain boundaries. In this work, we studied the resistivity of the Os films with different thicknesses as a function of temperature in the range of 20 to 296 K. The electron scattering by the surface was found to be unimportant in the contributions to the size effects of resistivity of Os films with a sufficient thickness. Based on the first-principles calculations, an analytical equation was suggested for correction to the MS model and used for fitting the temperature-dependent resistivity of the Os films. The results show that correction to the MS model is necessary and the residual resistivity caused by the defects and impurities cannot be neglected. In addition, the inhomogeneity of resistivity in the direction perpendicular to the film surface was discussed under an assumption of parallel circuits. [ABSTRACT FROM AUTHOR]

Electric transport coefficients such as carrier type, density, and mobility are the important physical parameters in designing functional devices. In this work, we report the study on the electric transport coefficients of the highly epitaxial LaBaCo2O5+δ (LBCO) films, which were discussed as a function of electric conductivity for the first time and compared with the results calculated by the theory for mixed conduction. The mobility in the LBCO films was determined to be ∼0.85 and ∼40 cm²/V s for holes and electrons, respectively, and the density of p-type carriers strongly depends on the oxygen deficiency. Solid evidence is presented to demonstrate that the oxygen deficiency cannot make LBCO materials changed from p- to n-type. The n-type conduction observed in experiment is a counterfeit phenomenon caused by the deficiency in Hall measurement, rather than a realistic transition induced by oxygen deficiency. In addition, the temperature-dependent conductivity was discussed using the differential coefficients, which might be useful in the study of the samples with magnetic transition. [ABSTRACT FROM AUTHOR]

• Drought propagation characteristics are analyzed over Central Asia. • BMA is used to build the relationship between drought propagation and factors. • The effects of factors on drought propagation are quantified by ANOVA. • Temperature is the most important factor on both propagation time and relationship. • The interactive effects of factors on drought propagation are significant. Drought poses a significant threat to agricultural sector, and meteorological drought (MD) is the main driver and origin of agricultural drought (AD). The process is susceptible to multiple potential factors, whereas there is a challenge in quantifying the effects of factors. This study develops a novel method named as BANOVA by combining Bayesian Model Averaging (BMA) with analysis of variance (ANOVA), and is tested in Central Asia which is an agricultural dominant area. Standardized Precipitation Index and Standardized Soil Moisture Index are calculated to characterize MD and AD from 1982 to 2014. Precipitation and soil moisture are provided by Climatic Research Unit Gridded Time Series and Global Land Data Assimilation System. The maximum Pearson correlation coefficients (MPCC) and drought propagation time (DPT) are selected to depict the process of drought propagation. The results suggest that BMA can effectively integrate the results of each machine learning model and reduce the uncertainty of model structure. Several findings can be summarized: (1) there is a stable relationship between AD and MD that MPCC are significant (p < 0.01) for all grids, and the average DPT is 2.8 months; (2) eight factors are selected for drought propagation simulation, and temperature plays the dominant role in both MPCC and DPT with the contribution of 86.2 % and 35.0 %; (3) the interactive effects of factors on drought propagation characteristics are significant, such as temperature and precipitation with the contribution of 13.2 % on drought propagation time. This study highlights the importance of temperature in drought propagation. Under the context of global warming, the propagation time and relationship between MD and AD will become shorter and closer, respectively. [ABSTRACT FROM AUTHOR]

Different electronic structure on 4 f shell endows rare earth with variable of catalytic activity. In order to explore the catalytic effect of rare earth on solid oxide fuel cell (SOFC) electrode, we prepare electrolyte-supported (Sr 1.8 Ln 0.2)FeMoO 6 /SDC/LSGM/SBCO single cell with Ln = Sr, La, Sm and Eu, and investigate their electrochemical performance based on X-ray diffraction (XRD), DC four-point probe, I-V and electrochemical impedance spectra. XRD results show that (Sr 1.8 Ln 0.2)FeMoO 6 are of single phase and belong to I4/m space group. Owing to the increased density of states, electronic conductivity of (Sr 1.8 La 0.2)FeMoO 6 (SLFM), (Sr 1.8 Sm 0.2)FeMoO 6 (SSFM) and (Sr 1.8 Eu 0.2)FeMoO 6 (SEFM) increases significantly, where SEFM exhibits the highest value in the measuring range. The higher conductivity and the smaller activation energy favor the power output of the investigated cell. The maximum power density of Sr 2 FeMoO 6 (SFMO)-based cell is 772 mW·cm−2 at 850 ℃, that of SLFM- and SSFM-based cell increases to 890.8 mW·cm−2 and 861.6 mW·cm−2, while SEFM-based cell exhibits the highest value of 964.6 mW·cm−2. Electrochemical Impedance Spectroscopy (EIS) finds that SEFM-based cell possesses the smallest electrode resistance, charge transfer resistance, the fastest surface exchange and oxygen diffusion process, which favors its highest power output. These results demonstrate that the synergistic reaction in catalytic activity between rare earth atoms and SFMO lattice is different to a large degree, and our innovative discovery is the good catalytic activity of SEFM anode, which is conducive to comprehensively understanding the catalytic properties of rare earth for SOFC electrodes. • The synergy in catalytic activity between rare earth and Sr 2 FeMoO 6 is different to a large degree. • (Sr 1.8 Eu 0.2)FeMoO 6 exhibits the highest conductivity. • (Sr 1.8 Eu 0.2)FeMoO 6 -based cell depicts the best electrochemical performance. [ABSTRACT FROM AUTHOR]

This article has been retracted. Please see the Retraction Notice for more detail: https://doi.org/10.1134/S1070328424030059 [ABSTRACT FROM AUTHOR]

Agricultural drought (AD) is disastrous to crop production and plant growth. The prediction of AD with sufficient lead time is helpful for developing agricultural water strategy, particularly under the context of global warming. However, the previous studies mainly focused on short lead times (1–6 months) and only used 3 or less variables to predict AD through copula models. In this study, a novel multivariate time series convolutional neural network (T-CNN) is developed to predict AD with long lead times based on multiple meteorological variables. To demonstrate its feasibility and novelty, T-CNN is used in the Aral Sea Basin (ASB) where agricultural production is dominant. Three global climate models (GCMs) and three shared socioeconomic pathways (SSPs) from CMIP6 are considered during 2026–2100. Results indicate that (1) precipitation, temperature, potential evapotranspiration, relative humidity and northward wind are significantly correlated with AD, and are selected as the predictors of AD; (2) compared with the conventional CNN and convolutional long short-term memory (ConvLSTM), T-CNN's performance is better, taking only about 10% of the computation time of ConvLSTM; (3) T-CNN can effectively extract the spatiotemporal characteristics of meteorological predictors and reproduce AD, showing high correlation coefficients (R>0.9) for 92.5% of the grids across ASB; (4) the result of simple model averaging (SMA) is better than other GCMs, indicating that the spatial differences in AD would become more pronounced with increasing time and emission level; (5) compared with the historical period, under SSP585, the extreme drought would increase 0.20 months/year (2026–2050), 0.23 months/year (2051–2075) and 0.28 months/year (2076–2100). The results highlight the spatiotemporal variation of AD in 21st century with a high resolution (0.1°×0.1°), which can provide scientific support for agricultural water management and long-term drought prevention in ASB. • T-CNN shows the highest computation efficiency compared with ConvLSTM and CNN. • T-CNN can effectively extract spatiotemporal features of meteorological predictors. • Long-term agricultural drought over the Aral Sea Basin is predicted by T-CNN. • The performance of simple model averaging is better than any other GCMs from CMIP6. • The spatial distribution differences of agricultural drought will become more obvious. [ABSTRACT FROM AUTHOR]

Ga 2 O 3 exhibits great potential for applications in solar-blind ultraviolet photo detector, high-power electronic devices and solid-state light-emitting due to its ultra-wide band gap and high Baliga figure of merit. Here, Ga 2 (N x O 1-x) 3 films with varied nitrogen contents were prepared by the sol-gel technique. XRD analysis reveals that nitrogen doping contributes for growth of greater crystalline and SEM-EDS measurements confirm that the monoclinic crystal structure of Ga 2 (N x O 1-x) 3 is maintained to doping level of 3.26wt%; FTIR information indicates that nitrogen prefers to substitute for the O 1 and O 2 site of Ga 2 O 3 ; XPS offers evidence that nitrogen tends to occupy oxygen vacancies and generate more gallium vacancies; UV-VIS shows that impurity defects appear above valence band, and the absorption position undergoes a red shift with nitrogen above 1.32wt%; PL shows Ga 2 (N x O 1-x) 3 films can emit light of various colors under excitation at 325nm, and the acceptor level is at 1.63eV∼2eV above the valence band; The conductivity of Ga 2 (N x O 1-x) 3 films is changed from n-type to p-type when nitrogen-doping is 0.96 wt% and the I–V curve composed of Ga 2 (N x O 1-x) 3 and Ga 2 O 3 shows PDCR = 43 under the 254nm light. Therefore, the development of nitrogen-doped β-Ga 2 O 3 has potential opportunities for applications in photoelectric devices. [Display omitted] • The N-doped Ga 2 O 3 is obtained for the first time using an incomplete redox process by sol-gel method. • N occupies the O 1 and O 2 site, promoting the generation of Ga vacancies. • Absorption position is red-shifted with the increase of N content. • The acceptor level formed by N doping is obtained at 1.63eV∼2eV above the valence band. • The conductivity of Ga 2 (N x O 1-x) 3 films is changed from n-type to p-type, when N doping is 0.96 wt%. [ABSTRACT FROM AUTHOR]

Cauliflower is one of the most important popular vegetables in China. Cauliflower (Brassica oleracea L. var. botrytis) produces glucosinolates, which are secondary metabolites that have anti-cancer properties. The choice of suitable reference genes (RGs) for gene expression studies has a significant effect on experimental outcomes. In this study, we selected 15 candidates as RGs and analyzed them under heat, cold, drought, and salt stresses and methyl jasmonate (MeJA) treatment. The precision of the real-time quantitative polymerase chain reaction data was assessed using four methods (geNorm, NormFinder, BestKeeper, and ΔCt). The results revealed that EF1-ß and ACT7; ACT1, EF1-ß, and TUB6; TUA2 and EF1-ß; HIS and ACT7; and ACT7 and ACT3 were the most stable combinations of genes for heat stress, cold stress, drought stress, salt stress, and MeJA treatment, respectively. The expression stability of the RGs fluctuated under different experimental conditions. Choosing the optimal RG for the specific experiment is therefore essential. This work provides relevant information for further gene expression studies on cauliflower and other closely related species. [ABSTRACT FROM AUTHOR]

The syntheses of 3-formyl-4-hydroxybenzoic acid-derived ligands from ethylenediamine, diethylenetriamine, and triethylenetetramine are described. These ligands can further form hetero-binuclear complexes with transition metal ions (M2+ = Zn2+, Fe2+, Ni2+, Mn2+) and lanthanide ions (Ln3+ = Nd3+, Er3+, Yb3+). The spectroscopic properties were studied using near-infrared (NIR) luminescence emission spectra, fluorescence lifetime, and quantum yield. These hetero-nuclear complexes exhibited the characteristic lanthanide near-infrared luminescence in the solid state through energy-transfer from the chromophore to lanthanide ions. The d-block emission bands of transition metal ions in the solid state overlapped with f–f absorption bands of Yb(III), Er(III), or Nd(III), sensitizing the near-infrared luminescence of these hetero-binuclear complexes. [ABSTRACT FROM AUTHOR]

The oxygen-evolving complex (OEC) of Zostera marina is prone to deactivation under visible light, which results in a formation of the long-lived radical P680+. The mechanism to prevent damage caused by P680+ remains unclear. In this study, following light exposure, the upregulation in ascorbate (AsA) content and the presence of PSII cyclic electron flow (PSII-CEF) provide evidence that AsA and PSII-CEF donate electrons to PSII. Furthermore, a factorial design experiment with different combinations of inhibition of AsA and PSII-CEF demonstrates that both inhibition treatments lead to decreases in maximal photochemical yield of PSII, increases in relative variable fluorescence at the K-step, as well as the net loss of PSII reaction center proteins and further degradation of OEC peripheral proteins. These results suggest that AsA and PSII-CEF play photoprotective roles by providing electrons to efficiently prevent damage to PSII from the highly oxidizing radical P680+ in Z. marina. [ABSTRACT FROM AUTHOR]

The doped LaGaO 3 is a well-known intermediate-temperature electrolyte due to its high ionic conductivity and negligible electronic conductivity. However, the phase pure La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3-δ (LSGM 9182) compound is not easy to be prepared because of its sensitive character with preparing process. In this work, the influence of evaporating temperature (glycine-nitrate combustion method) on the phase formation and physical property of LSGM 9182 is investigated systematically. The samples with different evaporating temperature 80 °C ≤ T ˂ 84 °C, 84 °C ≤ T ˂ 88 °C, 88 °C ≤ T ˂ 92 °C and T ≥ 92 °C was named as compound A, B, C and D. XRD results show that the phase pure compound can only be synthesized with the evaporating temperature 80 °C ≤ T ˂ 84 °C, the higher evaporating temperature, the higher content of LaSrGaO 4 or LaSrGa 3 O 7 impurity. Due to the slight change in composition, shoulders and splitting of some XRD reflections in phase pure compound A disappear for compound D, representing an transition from low-symmetry orthorhombic lattice to high-symmetry cubic lattice. Owing to the competiting contribution between crystal symmetry and impurity, the conductivity of compound D does not decrease almostly at low temperature, however, the influence of low conductive LaSrGaO 4 prevails at high temperature, consequently, the conductivity of compound D decreases to a large degree at 800 °C. Above results suggest that evaporating temperature is an important parameter to prepare high quality LSGM electrolyte, suitable evaporating temperature supplies proper energy for chemical reaction and produce single perovskite phase compound finally. • Evaporating temperature impacts strongly on the phase of LSGM 9182. • Structural transition happens and affects the conductivity. • Arrhenius plots exhibits non-linear dependence with reciprocal temperature. • Conductivity is reduced due to the presence of minor phase. [ABSTRACT FROM AUTHOR]

Light‐harvesting chlorophyll a/b binding (Lhc) family proteins play a significant role in photosynthetic processes. Our objective was systematic identification and analysis of the Lhc family in cotton, as well as the relationship between Lhc family genes and chlorophyll synthesis during photosynthetic processes.We used genome‐wide identification, phylogenetic analysis, chromosomal distribution and collinearity to examine potential functions of Lhc superfamily genes in upland cotton. Subcellular localization, qRT‐PCR, a yeast two hybrid (Y2H) , and Virus‐induced gene silencing (VIGS) experiment were used to explore function of GhLhcb2.3.Focusing on GhLhc family, gene structural analysis of G. hirsutum Lhc family genes (GhLhc) indicated the conservation of selected Lhc family members. The expression pattern of GhLhc proteins shows that Lhc family proteins are important for photosynthetic processes in leaves. Results of subcellular localization and qRT‐PCR in different cotton varieties showed that GhLhcb2.3 is closely related to chloroplast chlorophyll. Y2H found extensive heteromeric interactions between the GhLhcb2.3 and GhLhcb1.4. Subcellular localization revealed that GhLhcb1.4 is located in chloroplasts. VIGS showed that GhLhcb2.3 influenced chlorophyll a synthesis.We comprehensively identified Lhc family genes in cotton, characterized these genes and reveal the influence of GhLhcb2.3 on chlorophyll a synthesis. [ABSTRACT FROM AUTHOR]