An Instance Segmentation-Based Method to Obtain the Leaf Age and Plant Centre of Weeds in Complex Field Environments.

Leaf age and plant centre are important phenotypic information of weeds, and accurate identification of them plays an important role in understanding the morphological structure of weeds, guiding precise targeted spraying and reducing the use of herbicides. In this work, a weed segmentation method based on BlendMask is proposed to obtain the phenotypic information of weeds under complex field conditions. This study collected images from different angles (front, side, and top views) of three kinds of weeds (Solanum nigrum, barnyard grass (Echinochloa crus-galli), and Abutilon theophrasti Medicus) in a maize field. Two datasets (with and without data enhancement) and two backbone networks (ResNet50 and ResNet101) were replaced to improve model performance. Finally, seven evaluation indicators are used to evaluate the segmentation results of the model under different angles. The results indicated that data enhancement and ResNet101 as the backbone network could enhance the model performance. The F1 value of the plant centre is 0.9330, and the recognition accuracy of leaf age can reach 0.957. The mIOU value of the top view is 0.642. Therefore, deep learning methods can effectively identify weed leaf age and plant centre, which is of great significance for variable spraying.

Numerical analysis of synchronously pumped solid-state Raman lasers.

Considering the spatial distribution of laser beams and phonon waves, the SRS coupling wave equations in the transient regime are derived and normalized for the first time. The synchronously pumped solid-state Raman laser is simulated numerically to investigate the influences of the cavity length detuning, output coupling rate, dispersion, Raman gain and dephasing time of Raman mode on laser performances. It is found that the intensive pulse compression of first Stokes laser in synchronously pumped solid-state Raman laser stems from pulse width gain narrowing and intensity oscillation effects. The cavity length detuning, dispersion, Raman gain and dephasing time considerably affect the pulse width gain narrowing and intensity oscillation processes. The theoretical results can help the design and optimization of synchronously pumped solid-state Raman laser to generate ultrafast Raman laser output efficiently.

Effect of γ-PGA on the formation of collagen fibrils in vitro.

The effect of γ-poly(glutamic acid) (γ-PGA) on the self-assembly of collagen was studied. Under physiological conditions, the kinetic curves for fibril formation showed that the turbidity of collagen/γ-PGA blends at 313 nm was increased with the addition of γ-PGA. Furthermore, it was shown using both field-emission scanning electron microscopy (FESEM) and atomic force microscopy (AFM) that fibrils with a larger diameter were obtained following the addition of γ-PGA, probably due to the electrostatic and hydrogen bond interactions between collagen and γ-PGA, which promoted the lateral association of collagen molecules. In addition, both the thermal stability and viscoelastic properties of the hybrid hydrogels, which were evaluated by differential scanning calorimetry and rheological measurements, respectively, were improved by the addition of γ-PGA.

The essential role of GSTP1 I105V polymorphism in the prediction of CDNB metabolism and toxicity: In silico and in vitro insights.

Humans are continuously exposed to toxic chemicals such as nitro-chlorobenzene (CDNB) through occupation, water, and even the air we breathe. Due to the severe toxicity caused by the high electrophilicity of CDNB, occupational and environmental exposure to CDNB can produce toxic effects that ultimately lead to cell damage. CDNB can be eliminated from organisms by binding to GSH, the catalytic product of glutathione S-transferase P1 (GSTP1). Therefore, GSTP1 plays an important role in the detoxification of CDNB. However, subtle variations in GSTP1 can result in single nucleotide polymorphisms (SNPs). Indeed, the correlation between the clinical outcome of the disease and certain genotypes of GSTP1 has been extensively studied, however, their impact on the metabolic detoxification of toxicants such as CDNB remains to be elucidated. Among the various SNPs of GSTP1, I105V has a significant effect on the catalytic activity of GSTP1. In this paper, a GSTP1 I105V polymorphism model was successfully established, and its effect on CDNB metabolism and toxicity was studied by computer analysis including molecular docking and molecular dynamics simulation. The result demonstrated that the binding capacity of CDNB decreases with the I105V mutation of GSTP1(p < 0.001), indicating the changes in its detoxification efficacy in CDNB-induced cell damage. Organisms expressing GSTP1 V105 are more susceptible to cell damage caused by CDNB than individuals expressing GSTP1 I105 (p < 0.001). In sum, the data in this study provide prospective insights into the mechanism and capacity of CDNB detoxification in the GSTP1 allele, extending the CDNB-mediated toxicological profile. In addition, the heterogeneity of the GSTP1 allele should be included in toxicological studies of individuals exposed to CDNB.

[Study on the experimental application of floating-reference method to noninvasive blood glucose sensing].

Weak signal, low instrument signal-to-noise ratio, continuous variation of human physiological environment and the interferences from other components in blood make it difficult to extract the blood glucose information from near infrared spectrum in noninvasive blood glucose measurement. The floating-reference method, which analyses the effect of glucose concentration variation on absorption coefficient and scattering coefficient, gets spectrum at the reference point and the measurement point where the light intensity variations from absorption and scattering are counteractive and biggest respectively. By using the spectrum from reference point as reference, floating-reference method can reduce the interferences from variation of physiological environment and experiment circumstance. In the present paper, the effectiveness of floating-reference method working on improving prediction precision and stability was assessed through application experiments. The comparison was made between models whose data were processed with and without floating-reference method. The results showed that the root mean square error of prediction (RMSEP) decreased by 34.7% maximally. The floating-reference method could reduce the influences of changes of samples' state, instrument noises and drift, and improve the models' prediction precision and stability effectively.

2-Phenyl-imidazolium hemi(benzene-1,4-dicarboxyl-ate) trihydrate.

The asymmetric unit of the title compound, C(9)H(9)N(2) (+.)0.5C(8)H(4)O(4) (-)·3H(2)O, contains one 2-phenyl-imidazolium cation, half a benzene-1,4-dicarboxyl-ate anion and three water mol-ecules, which are connected by O-H⋯O and N-H⋯O hydrogen bonds into a three-dimensional network.

catena-Poly[[[bis-[4-(1H-1,3,7,8-tetra-azacyclo-penta-[l]phenanthren-2-yl)phenol-κN,N]manganese(II)]-µ-naphthalene-1,4-dicarboxyl-ato-κO:O] naphthalene-1,4-dicarboxylic acid hemisolvate monohydrate].

The 1,4-dicarboxyl-ate dianions in the title compound, [Mn(C(12)H(6)O(4))(C(19)H(12)N(4)O)(2)]·0.5C(12)H(8)O(4)·H(2)O, bond to two 4-(1H-1,3,7,8-tetra-azacyclo-penta-[l]phenanthren-2-yl)phenol-chelated Mn atoms to form a chain that features the metal atom in an octa-hedral coordination geometry. Adjacent chains inter-act with the uncoordinated water mol-ecules to form a three-dimensional network. The naphthalene-1,4-dicarboxylic acid solvent mol-ecule, which is disordered about a centre of inversion, occupies the space within the network but is not bonded to the network. One NH group is disordered equally over two positions.

Poly[[µ(4)-naphthalene-1,4-dicarboxyl-ato-κO:O':O'':O'''-µ(2)-naphthalene-1,4-dicarboxyl-ato-κO,O':O'',O'''-bis-(2-phenyl-1H-1,3,7,8-tetra-azacyclopenta-[l]phenanthrene-κN,N)dimanganese(II)] N,N-dimethyl-formamide solvate].

One of the two 1,4-dicarboxyl-ate dianions in the title compound, [Mn(2)(C(12)H(6)O(4))(2)(C(19)H(12)N(4))(2)]·C(3)H(7)NO, uses its two carboxyl-ate groups to chelate two N-heterocycle-chelated Mn atoms; the other 1,4-dicarboxyl-ate dianion binds to four such metal centers. The octa-hedrally coordinated Mn atoms are linked through the two dianions into a layer motif; the dimethyl-formamide mol-ecules occupy the spaces between adjacent layers. Ten C atoms and attached H atoms of one dianion are disordered equally over two positions.

[Properties of synthesized CdS nanoparticles by reverse micelle method].

Micelle system with reverse phase (water/CTAB/n-hexyl alcohol/n-heptane) is a weenie liquid-globelet of surface active agent molecule which can be stably and uniformly dispersed in continuous oil medium. The micelle system with reverse phase can work as a "micro-reactor" to synthesize CdS nano-particle with excellent performance. In the present article considering the effects of W value (W= [water]/[surface agent]) of the micelle system with reverse phase, we observed that the ratio of [Cd2+] and [S2-] ions to the original concentrations of the Cd2+ and S2- ions can affect the luminescent properties of CdS nano-particle. Using regurgitant treatment process the surface of CdS nano-particle can be modified, and as a result the defect emission was reduced and even disappeared, but exciton emissions markedly increased. On the other hand, a red-shift of the exciton emission peak with the increase in the particle size was observed, indicating considerable quantum confinement effect. A maximum quantum efficiency of 11% for the synthesized CdS nano-material was achieved.