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To investigate the effects of biochar on the quality improvement of tobacco planting soil and tobacco production, a field experiment with 5 treatments: T0, 0 t/hm² biochar + 0.64 t/hm² nitrogen fertilizer; T1, 0.5 t/hm² biochar+0.64 t/hm² nitrogen fertilizer; T2, 1 t/hm² biochar+0.64 t/hm² nitrogen fertilizer; T3, 1.5 t/hm² biochar+0.64 t/hm² nitrogen fertilizer; T4, 2 t/hm² biochar+0.64 t/hm² nitrogen fertilizer was conducted. The effects of biochar on the carbon emission and organic carbon components of tobacco planting soils and tobacco physiological indexes were analyzed. The results showed that: 1) Compared with treatment T0, treatments T1, T2 and T3 reduced the total soil carbon emission by 28.14%, 25.25% and 8.41% respectively; and treatment T4 raised the total soil carbon emission by 8.79%. 2) The biochar treatments increased the contents (mass fractions) of soil total organic carbon, microbial biomass carbon, soluble organic carbon and easily oxidized organic carbon. On the 70th day after transplanting, the total organic carbon and microbial biomass carbon in soils of treatment T4 were 19.38% and 29.38% higher than those of treatment T0. The proportion of microbial biomass carbon in total organic carbon decreased, while the proportion of soluble organic carbon in total organic carbon increased with the application of biochar. 3) The biochar treatments promoted tobacco root vigor, the photosynthetic characteristics of tobacco leaves and the dry matter accumulation in tobacco plants. Among them, treatment T3 increased tobacco root vigor by 80.43% comparing with treatment T0. Therefore, suitable biochar applications can reduce soil carbon emission, increase contents of different soil carbon components, promote the root growth and development, photosynthetic characteristics and dry matter accumulation of tobacco plants. [ABSTRACT FROM AUTHOR]

In order to explore the technological way of improving tobacco soil by biomass carbon, this paper studied the effect of interaction between biochar of different pyrolysed temperatures (360°C and 500°C) and soil textures (loam soil and sandy soil) on dynamic change of nitrate nitrogen content and apparent N loss of soil-tobaco plant system in 0~30 cm soil layer. The results showed that: 1 Applying biochar could increase N03-N contents in soil. The soil NO3-N contents in application of biochar treated by low-temperature (360°C) and high-temperature (500T°C) increased by 20.58% and 8.97% than that of the control group. Soil N03-N retention capacity applied with low-temperature pyrolysed biochar is better than that with high-temperature pyrolysed biochar. 2 The effect of low-temperature carbon on soil N03-N was mainly occurred in 0~10 cm soil layer. While, that of high-temperature carbon was in 10~20 cm soil layer. Their effects were 38.39% and 7.37% higher than that of the control, respectively, and all reached the significant level. 3 The NO3-N contents in loam soil and sandy soil were 16.09% and 29.18% higher than that oi the control, respectively, indicating the fertilizer retention effect of applying low-temperature biochar in sandy soil was better than that in loam soil. The NO3-N contents in loam soil and sandy soil with application of high-temperature biochar were 11.03% or 4.97% higher, respectively than that of the control. It indicated the fertilizer retention effect of applying high-temperature biochar in loam soil was better than that in sandy soil. 4 Application of biochar could reduce the apparent N loss of soil-tobacco plant system. The effect of low-temperature biochar was better than that of high-temperature biochar. The apparent N loss of each treatment (chemical fertilizer + low-temperature biochar in loam soil, chemical fertilizer + high-temperature biochar in loam soil, chemical fertilizer + low-temperature biochar in sandy soil, chemical fertilizer + high-temperature biochar in sandy soil) was decreased by 40.27%, 34.10%, 68.72% and 54.05%, respectively than that of the control. Therefore, applying biochar could strengthen soil NO3-N retention capacity and reduce apparent N loss in soil-tobacco plant system. The effect of low-temperature biochar was more significant than that of high-temperature biochar. This study provided theoretical guidance for rational application of biochar in tobacco-planting soil. [ABSTRACT FROM AUTHOR]

Objective: To evaluate signal intensity-time (SI-Time) curve and quantitative dynamic contrast-enhanced 3.0T magnetic resonance imaging in diagnosis and differentiating neoplasm of uterus.
, Methods: A total of 42 cases of uterine neoplasm (20 were malignant and 22 were benign) were evaluated in our study. All cases received dynamic contrast-enhanced scanning on 3.0T MRI. The raw data was processed by Siemens Tissue 4D software and the SI-Time curve was obtained and analyzed. Pharmacokinetic modeling of Tofts with a modeled vascular input function was used for calculating volume parameters: volume transfer constant (Ktrans), reverse volume transfer constant (Kep), the extravascular extracellular space volume per unit volume of tissue (Ve). The correlation of these parameters at each groups were investigated. The SI-Time curve and the data of perfusion parameters between the 2 groups were compared by T test.
, Results: Among 20 malignant tumors, 12 were cervical carcinoma and 8 were endometrial cancer. Among the benign tumors, 13 were leiomyomas, 3 were endometrial polyp, 3 were endometrial hyperplasia, and 3 were adenomyosis. 59.1% cases of benign tumors belong to Type I curve and 65% cases of malignant tumors belong to Type II curve. There was significant difference in SI-Time curve between benign and malignant tumors (P=0.011). If Type I curve was used as diagnostic criteria for benign tumors, and Type II and III curve were for malignant tumors, the diagnostic sensitivity, specificity, positive predictive value, negative predictive value were 90.0%, 59.1%, 66.7%, and 86.7%, respectively. Ve was 0.477 ± 0.143 in malignant and 0.614 ± 0.146 in control group with significant difference (P=0.004). Ve was 0.477 ± 0.143 in malignant and 0.589 0.176 in benign group with significant difference (P=0.004). Ktrans was (0.178 ± 0.067) min⁻¹ in malignant and (0.263 ± 0.111) min⁻¹ in control group with significant difference (P=0.003). Ktrans was (0.182 ± 0.096) min⁻¹ in benign and (0.263 ± 0.111) min⁻¹ in control group with significant difference (P=0.011). 
, Conclusion: The type of SI-Time curve and perfusion parameters were important for differentiating benign and malignant uterine tumors in dynamic enhanced MRI. These parameters provide a supplement for conventional morphological MR diagnosis.

Objective: We screened dominating microbial species isolated from aging flue-cured tobacco and studied their aroma improving effect., Methods: Total DNA of microorganisms from the fermentation flue-cured tobacco surface of NC89, ZhongYan 100 and ZhongYan 101 were extracted. Under the PCR-DGGE, the diversity of microorganisms on fermentation tobacco leaves were studied and dominating microbial species were screened. We further studied the influence of dominating microbial species on the content of aroma components of the fermentation flue-cured tobacco., Results: 1) By using DGGE analysis, there were 5 dominant bands A, B, C, D and E in all tobacco leaves samples of the three varieties; In further studies, five dominant DGGE bands were isolated, cloned and sequenced. From them we screened a dominant microorganism. 2) The content of most aroma components in tobacco leaves increased when they were sprayed with the dominant microorganism, comparing with the control., Conclusion: The dominant microorganism can improve the flavor of tobacco leaves during ripening.

A reversed-phase high performance liquid chromatographic (RP-HPLC) method for the determination of carotenoids in flue-cured tobacco leaves was developed. Carotenoids were extracted from flue-cured tobacco leaves by acetone-water (90:10, v/v) solution containing 0.1% butylated hydroxytoluene (BHT). Plant proteins were eliminated by adding 0.1 g Pb(Ac)2 and by centrifugation (10000 r/min) for 5 min at 4 degrees C. Lutein, beta-carotene, neoxanthin, violaxanthin and other plant pigments were separated on a reversed-phase C18 column (3.9 mm i.d. x 150 mm, 5 microm), with a mobile phase of (A) methanol-isopropyl alcohol (1:1, v/v) and (B) water using a gradient elution at a flow rate of 0.5 mL/min. The optimum elution gradient was as follows: 0-10 min, 70% A + 30% B; 10-17 min, 100% A; 17-30 min, 90% A + 10% B. The recoveries of carotenoids in flue-cured tobacco leaves were 91.77%-97.42%, and relative standard deviations were 3. 46%-0.98%. This method was applied to determine carotenoids in flue-cured tobacco leaves during its growth with satisfactory results.