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Japonica rice variety Kanto 194 as the donor of resistance gene Stv-bi and low-amylose content gene Wx-mq was used to improve the resistance and eating quality of Wuyujing 3 by the breeding strategy of backcross. In continuous backcross and selfcross generations, the related molecular markers with Stv-bi and Wx-mq genes were utilized for genotypic detection by associated with resistance identification of rice stripe disease and agronomic traits selection. Finally, 10 improved lines with homozygous genotype Stv-biStv-biWx-mqWx-mq were obtained from BC3F4 generation. The results of comparative analysis indicated that most characters of these lines were consistent with those of recipient parent Wuyujing 3, except for the improved resistance, appearance and eating quality. By evaluation of the comprehensive performance of them, two excellent lines K01 and K04 were selected for further experiments.

GW2 is an important gene that regulates grain width and weight. We used cDNA clone to obtain the sequences of GW2 from large- and small-grained rice varieties, TD70 and Kasalath, respectively. Then, we developed a dCAPS (derived cleaved amplified polymorphic sequence) marker on the basis of the sequence difference between functional and nonfunctional GW2 genes to analyze the genotypes and phenotypes of recombinant inbred lines. Results showed that the sequence of GW2TD70 had a single nucleotide deletion at site 316 that generates a termination codon. This codon terminated the GW2 protein in advance. By contrast, the sequence of GW2Kasalath encoded an intact protein. A novel dCAPS marker was designed in accordance with a base A deletion at site 316 of the sequence. After the PCR product was digested by ApoI, TD70 showed 21 and 30 bp fragments, and Kasalath showed a 51 bp fragment. Up to 82 lines contained GW2TD70, and 158 lines contained GW2Kasalath. The lines that contained TD70 alleles displayed substantial increases in width and 1000-grain weight. This result suggested that GW2 played a critical role in rice breeding.

In this brief, a new approach of using 1.D map in digital chaotic encryption systems is presented. This scheme utilizes a class of 1-D piecewise linear (PWL) map with different discretization on its input and output terminals to realize finite-precision chaotic encryption and decryption systems through the inverse system approach. This kind of map has the property of different discrete-value sets on its input and output terminals, and is called a dual-resolution map. The general structure of encryption systems that utilize a dual-resolution map is proposed, in which a dynamical system [Sigma]([multiplied by]) is used to connect the n-order delay line with the input terminal of the dual-resolution map. An example encoder with a four-order delay line is given to promote an understanding of the performance of this new type nonlinear digital encryption system. Simulation results shows that the zero-response of the encoder has a d-like auto-correlation function and the response sequences converge to cyclic sequences with long period. The decoder (inverse system of the encoder) is sensitive to all parameter mismatches, so it can provide high security of the encrypted signals and can be used in real-time digital secure communications when high security is needed. Index Terms--Digital chaotic encryption, discretization, dual-resolution map.

Milk is an important consumer product with high nutritional value. The presence of veterinary drug residues in milk owing to the indiscriminate use of veterinary drugs may affect consumer health. In the mass spectrometric analysis of trace compounds, chromatographic co-eluting components easily interfere with the mass spectral signals obtained, affecting the accuracy of qualitative and quantitative analyses. Matrix purification is a promising method to reduce the matrix effect. Chitosan is a natural biopolymer with numerous active functional groups such as amino, acetyl, and hydroxyl groups; these groups can adsorb lipids through hydrophobic and electrostatic interactions. Chitosan also has the advantages of low production cost, stable chemical properties, and convenient modification. Novel chitosan-based materials are promising candidates for lipid purification. In this study, a chitosan membrane was modified with trimethoxyoctadecylsilane (C 18 -CSM). C 18 -CSM was prepared through one-step hydrolysis and used as a dispersive solid phase extraction (DSPE) adsorbent to purify the matrix during milk pretreatment. We combined C 18 -CSM with ultra-high performance liquid chromatography-quadrupole/electrostatic field orbitrap mass spectrometry (UHPLC-Q/Exactive Orbitrap MS) to develop an effective method for the extraction and determination of ofloxacin, enrofloxacin, ciprofloxacin, diazepam, and metronidazole in milk. C 18 -CSM was characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and water contact angle testing. The results indicated that the material has a rough surface and uniformly dense cross-section. The water contact angle of C 18 -CSM was 104°, indicating its good hydrophobicity. The pretreatment conditions (extraction solvent, dosage of NaCl, extraction frequency, and dosage of C 18 -CSM) that influenced the recoveries of the five veterinary drugs were investigated in detail. The optimal conditions were established as follows: 5% formic acid in acetonitrile, 1 g NaCl, extraction 1 time, 20 mg C 18 -CSM. Separation was performed on a Hypersil GOLD VANQUISH column (100 mm×2.1 mm, 1.9 μm). The mobile phase consisted of 0.1% formic acid aqueous solution and 0.1% formic acid in acetonitrile, and was flowed at a rate of 0.3 mL/min. The sample injection volume was 1 μL, and the column temperature was maintained at 25 ℃. Mass spectrometric analysis was performed in positive electrospray ionization mode. To verify the necessity of the purification material, the matrix effect was investigated using the matrix-matched standard curve method. The use of C 18 -CSM reduced the matrix effects of the five necessity drugs from the range of -22%-8.8% to the range of -13%-3.6%, indicating that C 18 -CSM is a highly efficient DSPE material. Under optimal conditions, the developed method showed good linearities within the range of 0.5-100 μg/L, with correlation coefficients ( r 2 )≥0.9970. The limits of detection(LODs) and quantification (LOQs) were 0.2 μg/L and 0.5 μg/L, respectively. To assess the accuracy and precision of the method, we prepared milk samples with three spiked levels (low, medium, and high). The recoveries of the five veterinary drugs were ranged from 79.5% to 115%, and the intra-day and inter-day relative standard deviations were 7.0%-13% ( n =6) and 1.3%-11% ( n =3), respectively. This study provides a simple, accurate, and reliable method for the rapid and simultaneous determination of the five veterinary drug residues in milk.