Chemoselective Synthesis of Unsymmetrical Dithioacetals through Sequential Carbene Insertion and Acetal Exchange of Acylsilanes and Thiols under Visible Light Irradiation.

Dithioacetals are a frequently used motif in synthetic organic chemistry, and most existing reports discuss only symmetrical dithioacetals. Examples of unsymmetrical dithioacetals are scarce, and few general methods for the selective synthesis of these compounds exists. An intriguing visible-light-induced strategy has been established in this work for sequential reactions of S-H insertion and acetal exchange between acylsilanes and two different thiols that deliver a wide variety of unsymmetrical dithioacetals in moderate yields. The unsymmetrical dithioacetals were obtained with high selectivity, and a great variety of functional groups were tolerated.

Estimation of Target Motion Parameters from the Tonal Signals with a Single Hydrophone.

In the shallow-water waveguide environment, the tonal signals radiated by moving targets carry modal interference and Doppler shift information. The modal interference can be used to obtain the time of the closest point of approach (tCPA) and the ratio of the range at the closest point of approach to the velocity of the source (rCPA/v). However, parameters rCPA and v cannot be solved separately. When tCPA is known, the rCPA and the v of the target can be obtained theoretically by using the Doppler information. However, when the Doppler frequency shift is small or at a low signal-to-noise ratio, there will be a strong parametric coupling between rCPA and v. In order to solve the above parameter coupling problem, a target motion parameter estimation method from tonal signals with a single hydrophone is proposed in this paper. The method uses the Doppler and modal interference information carried by the tonal signals to obtain two different parametric coupling curves. Then, the parametric coupling curves can be used to estimate the two motion parameters. Simulation experiments verified the rationality of this method. The proposed method was applied to the SWellEx-96 and speedboat experiments, and the estimation errors of the motion parameters were within 10%, which shows the method is effective in its practical applications.

Two-Way Concept-Cognitive Learning via Concept Movement Viewpoint.

Representation and learning of concepts are critical problems in data science and cognitive science. However, the existing research about concept learning has one prevalent disadvantage: incomplete and complex cognitive. Meanwhile, as a practical mathematical tool for concept representation and concept learning, two-way learning (2WL) also has some issues leading to the stagnation of its related research: the concept can only learn from specific information granules and lacks a concept evolution mechanism. To overcome these challenges, we propose the two-way concept-cognitive learning (TCCL) method for enhancing the flexibility and evolution ability of 2WL for concept learning. We first analyze the fundamental relationship between two-way granule concepts in the cognitive system to build a novel cognitive mechanism. Furthermore, the movement three-way decision (M-3WD) method is introduced to 2WL to study the concept evolution mechanism via the concept movement viewpoint. Unlike the existing 2WL method, the primary consideration of TCCL is two-way concept evolution rather than information granules transformation. Finally, to interpret and help understand TCCL, an example analysis and some experiments on various datasets are carried out to demonstrate our method's effectiveness. The results show that TCCL is more flexible and less time-consuming than 2WL, and meanwhile, TCCL can also learn the same concept as the latter method in concept learning. In addition, from the perspective of concept learning ability, TCCL is more generalization of concepts than the granule concept cognitive learning model (CCLM).

[Nitrogen content inversion of wheat canopy leaf based on ground spectral reflectance data]. / åŸºäºŽåœ°é¢è§‚æµ‹å ‰è°±æ•°æ®çš„å†¬å°éº¦å† å±‚å¶ç‰‡æ°®å«é‡åæ¼”æ¨¡åž‹.

Canopy nitrogen content in wheat is a key indicator of wheat grain yield and quality. When using remote sensing technology to predict wheat canopy nitrogen content, a hyperspectral mode with high adaptability and high accuracy is needed to improve the inversion efficiency. We developed a new three-band spectral vegetation index (NEW-NDRE) by combining a two-band spectral index NDRE and the spectral reflectance at 550 nm based on field data collected from different sites, years, with different varieties and nitrogen levels and at multiple growth stages. The NEW-NDRE was compared with 11 traditional spectral vegetation indices in terms of wheat canopy nitrogen content inversion. NEW-NDRE and three traditional indices (NDRE, NDDA and RI-1dB) all closely correlated with wheat canopy nitrogen content. NEW-NDRE displayed the highest correlation with wheat canopy nitrogen content at early grain filling stage, with a coefficient (R2) of 0.9 and a root mean squared error (RMSE) of 0.4. The inversion model developed with the NEW-NDRE was validated with an independent dataset. The relative error (RE) of the model was 9.3%, which was significantly lower than that of NDRE, NDDA and RI-1dB. Generally, NEW-NDRE is a more robust index for wheat canopy nitrogen content inversion than traditional indices through eliminating environmental limitation, and it could be used as a new tool for precise fertilizer application.

Non-Invasive Sensing of Nitrogen in Plant Using Digital Images and Machine Learning for Brassica Campestris ssp. Chinensis L.

Monitoring plant nitrogen (N) in a timely way and accurately is critical for precision fertilization. The imaging technology based on visible light is relatively inexpensive and ubiquitous, and open-source analysis tools have proliferated. In this study, texture- and geometry-related phenotyping combined with color properties were investigated for their potential use in evaluating N in pakchoi (Brassica campestris ssp. chinensis L.). Potted pakchoi treated with four levels of N were cultivated in a greenhouse. Their top-view images were acquired using a camera at six growth stages. The corresponding plant N concentration was determined destructively. The quantitative relationships between the nitrogen nutrition index (NNI) and the image-based phenotyping features were established using the following algorithms: random forest (RF), support vector regression (SVR), and neural network (NN). The results showed the full model based on the color, texture, and geometry-related features outperforms the model based on only the color-related feature in predicting the NNI. The RF full model exhibited the most robust performance in both the seedling and harvest stages, reaching prediction accuracies of 0.823 and 0.943, respectively. The high prediction accuracy of the model allows for a low-cost, non-destructive monitoring of N in the field of precision crop management.

Electrical conductivity of nutrient solution influenced photosynthesis, quality, and antioxidant enzyme activity of pakchoi (Brassica campestris L. ssp. Chinensis) in a hydroponic system.

To find an electrical conductivity (EC) in the nutrient solution used for pakchoi (Brassica campestris L. ssp. Chinensis) cultivation that optimizes the plant's physiology, growth, and quality, we conducted an experiment with eight EC treatments (from EC0 to EC9.6) in a hydroponic production system (i.e. soilless culture) under greenhouse condition in Shanghai, China. Plants biomass production, leaf photosynthesis, vegetable quality variables, tissue nitrate and nitrite contents, and antioxidant enzyme activities were measured. The results showed that very high (EC9.6) or low EC (EC0-0.6) treatments clearly decreased plants fresh weight (FW) and dry weight (DW), leaf size, leaf water content, leaf net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and taste score. Nitrite content, and antioxidant enzyme activities were low in medium EC treatments (EC1.8 and EC2.4), but high in very high or low EC treatments. Leaf relative chlorophyll, ascorbic acid, and nitrate contents increased gradually from low EC to high EC treatments, while crude fiber and soluble sugar contents decreased. Based on growth and quality criteria, the optimal EC treatment would be EC1.8 or EC2.4 for pakchoi in the hydroponic production system. Too high or too low EC would induce nutrient stress, enhance plant antioxidant enzyme activities, and suppress pakchoi growth and quality.

A novel integrated non-targeted metabolomic analysis reveals significant metabolite variations between different lettuce (Lactuca sativa. L) varieties.

Lettuce is an important leafy vegetable that represents a significant dietary source of antioxidants and bioactive compounds. However, the levels of metabolites in different lettuce cultivars are poorly characterized. In this study, we used combined GC × GC-TOF/MS and UPLC-IMS-QTOF/MS to detect and relatively quantify metabolites in 30 lettuce cultivars representing large genetic diversity. Comparison with online databases, the published literature, standards as well using collision cross-section values enabled putative identification of 171 metabolites. Sixteen of these 171 metabolites (including phenolic acid derivatives, glycosylated flavonoids, and one iridoid) were present at significantly different levels in leaf and head type lettuces, which suggested the significant metabolomic variations between the leaf and head types of lettuce are related to secondary metabolism. A combination of the results and metabolic network analysis techniques suggested that leaf and head type lettuces contain not only different levels of metabolites but also have significant variations in the corresponding associated metabolic networks. The novel lettuce metabolite library and novel non-targeted metabolomics strategy devised in this study could be used to further characterize metabolic variations between lettuce cultivars or other plants. Moreover, the findings of this study provide important insight into metabolic adaptations due to natural and human selection, which could stimulate further research to potentially improve lettuce quality, yield, and nutritional value.

Discrimination of plant root zone water status in greenhouse production based on phenotyping and machine learning techniques.

Plant-based sensing on water stress can provide sensitive and direct reference for precision irrigation system in greenhouse. However, plant information acquisition, interpretation, and systematical application remain insufficient. This study developed a discrimination method for plant root zone water status in greenhouse by integrating phenotyping and machine learning techniques. Pakchoi plants were used and treated by three root zone moisture levels, 40%, 60%, and 80% relative water content. Three classification models, Random Forest (RF), Neural Network (NN), and Support Vector Machine (SVM) were developed and validated in different scenarios with overall accuracy over 90% for all. SVM model had the highest value, but it required the longest training time. All models had accuracy over 85% in all scenarios, and more stable performance was observed in RF model. Simplified SVM model developed by the top five most contributing traits had the largest accuracy reduction as 29.5%, while simplified RF and NN model still maintained approximately 80%. For real case application, factors such as operation cost, precision requirement, and system reaction time should be synthetically considered in model selection. Our work shows it is promising to discriminate plant root zone water status by implementing phenotyping and machine learning techniques for precision irrigation management.

Long-term manure amendments and chemical fertilizers enhanced soil organic carbon sequestration in a wheat (Triticum aestivum L.)-maize (Zea mays L.) rotation system.

BACKGROUND: The carbon sequestration potential is affected by cropping system and management practices, but soil organic carbon (SOC) sequestration potential under fertilizations remains unclear in north China. This study examined SOC change, total C input to soil and, via integration of these estimates over years, carbon sequestration efficiency (CSE, the ratio of SOC change over C input) under no fertilization (control), chemical nitrogen fertilizer alone (N) or combined with phosphorus and potassium fertilizers (NP, NK, PK and NPK), or chemical fertilizers combined with low or high (1.5×) manure input (NPKM and 1.5NPKM). RESULTS: Results showed that, as compared with the initial condition, SOC content increased by 0.03, 0.06, 0.05, 0.09, 0.16, 0.26, 0.47 and 0.68 Mg C ha-1 year-1 under control, N, NK, PK, NP, NPK, NPKM and 1.5NPKM treatments respectively. Correspondingly, the C inputs of wheat and maize were 1.24, 1.34, 1.55, 1.33, 2.72, 2.96, 2.97 and 3.15 Mg ha-1 year-1 respectively. The long-term fertilization-induced CSE showed that about 11% of the gross C input was transformed into SOC pool. CONCLUSION: Overall, this study demonstrated that decade-long manure input combined with chemical fertilizers can maintain high crop yield and lead to SOC sequestration in north China. © 2016 Society of Chemical Industry.

Exogenous Glycine Nitrogen Enhances Accumulation of Glycosylated Flavonoids and Antioxidant Activity in Lettuce (Lactuca sativa L.).

Glycine, the simplest amino acid in nature and one of the most abundant free amino acids in soil, is regarded as a model nutrient in organic nitrogen studies. To date, many studies have focused on the uptake, metabolism and distribution of organic nitrogen in plants, but few have investigated the nutritional performance of plants supplied with organic nitrogen. Lettuce (Lactuca sativa L.), one of the most widely consumed leafy vegetables worldwide, is a significant source of antioxidants and bioactive compounds such as polyphenols, ascorbic acid and tocopherols. In this study, two lettuce cultivars, Shenxuan 1 and Lollo Rossa, were hydroponically cultured in media containing 4.5, 9, or 18 mM glycine or 9 mM nitrate (control) for 4 weeks, and the levels of health-promoting compounds and antioxidant activity of the lettuce leaf extracts were evaluated. Glycine significantly reduced fresh weight compared to control lettuce, while 9 mM glycine significantly increased fresh weight compared to 4.5 or 18 mM glycine. Compared to controls, glycine (18 mM for Shenxuan 1; 9 mM for Lollo Rossa) significantly increased the levels of most antioxidants (including total polyphenols, α-tocopherol) and antioxidant activity, suggesting appropriate glycine supply promotes antioxidant accumulation and activity. Glycine induced most glycosylated quercetin derivatives and luteolin derivatives detected and decreased some phenolic acids compared to nitrate treatment. This study indicates exogenous glycine supplementation could be used strategically to promote the accumulation of health-promoting compounds and antioxidant activity of hydroponically grown lettuce, which could potentially improve human nutrition.

[Clinical significance of dynamic monitoring the minimal residual disease in childhood B-lineage acute lymphoblastic leukemia by multiparameter flow cytometry].

This study was aimed to explore the clinical significance of monitoring level of minimal residual disease (MRD) at different time point in B-lineage childhood acute lymphoblastic leukemia (B-ALL). Two hundred and six children with B-ALL were enrolled in this study from Augest 2008 to September 2011 in our hospital. MRD levels were detected by flow cytometry at day 15, 33 and week 12 after initial chemotherapy. The event-free survival (EFS) for patients based on MRD levels measured at different stages of chemotherapy were compared by Kaplan Meier analyses. The results showed that out of 206 cases 196 cases achieved complete remission (CR) after induction therapy (CR rate 95.1%), the 1- and 3-year EFS rate were (92.7 ± 1.8)% and (78.7 ± 3.7)%, respectively, and the 3-year EFS rate was (85.6 ± 4.9)% in standard risk group, (82.1 ± 5.8)% in intermediate risk group and (58.1 ± 9.2)% in high risk group, there was significant statistical difference between above mentioned 3 groups (P < 0.001). The MRD analysis at different time points showed that the higher the MRD level, the lower the 3-year EFS rate of children with ALL, in which the 3-year EFS rate of MRD ≥ 10(-2) at day 15, MRD ≥ 10(-3) at day 33 and MRD ≥ 10(-3) at week 12 were significantly lower. The MRD ≥ 10(-3) at week 12 was proven to be an independent predictor by multivariate Cox proportional-hazards regression model. The 3-year EFS rate for patients with MRD < 10(-3) and MRD ≥ 10(-3) at week 12 were (86.3 ± 4.1)% vs (55.8 ± 9.1)% (P < 0.05); 8 relapsed among 98 cases with negative MRD (MRD < 10(-4)) at day 33, 19 relapsed among 108 cases with positive MRD at day 33 between the two groups for recurrence rate has significant difference (P < 0.05). It is concluded that dynamically monitoring MRD by multi-parameter flow cytometry can precisely evaluate treatment response, judge treatment outcome and predict relapse in childhood B-ALL. The MRD 10(-2) at day 15, MRD 10(-3) at day 33 and MRD 10(-3) at week 12 should be considered as the best cut-off. MRD ≥ 10(-3) at week 12 was proven to be an independent factor of poor prognosis.

[Expression of two subtype molecules of CD133 in childhood with B linage acute lymphoblastic leukemia and its clinical significance].

This study was to explore the expression of two subtype molecules of CD133 and its relationship with clinical prognostic factors in childhood with B linage acute lymphoblastic leukemia (B-ALL) at initial diagnosis and the 33rd day of induction chemotherapy. Expression of CD133-1 and CD133-2 in 48 cases of B-ALL and 25 cases at initial diagnosis and the 33rd day of treatment was detected by flow cytometry. Minimal residual disease (MRD) of B-ALL at 33rd day was evaluated by flow cytometry. The results indicated that the expression of CD133-1 was positive in 18 cases (37.5%), and expression of CD133-2 in 30 cases (62.5%) was positive from 48 cases with newly diagnosed ALL (P < 0.05). At 33rd day of treatment, expression of CD133-1 in 2 cases (8.0%) from 25 cases was positive, and expression of CD133-2 in 23 cases (92.0%) was positive (P < 0.05). After induction chemotherapy in B-ALL, the expression of CD133-1 decreased significantly, but still higher than that in the normal control group. Compared to expression of CD133-1, expression of CD133-2 decreased slowly. It is concluded that there is no relations among expression of CD133 and sex, age, white blood cell count, percentage of bone marrow blast cells, FAB subtype, cytogenetics, leukemia fusion gene, risk stratification and complete remission rate in childhood B-ALL. The positive expression rates and levels of CD133-2 are higher than those of CD133-1 in B-ALL. There is no statistical correlation between expression of CD133 and CD34 in B-ALL. The expression of CD133-2 is significantly related to the level of MRD.

[Analysis of clinical features and prognostic significance of childhood T-lineage acute lymphoblastic leukemia].

This study was aimed to explore the clinical features and prognosis outcome of childhood T-cell acute lymphoblastic leukemia (T-ALL). The clinical data of 38 cases of newly diagnosed T-ALL from Jan 2005 to Aug 2010 were analyzed retrospectively, and 78 cases of B-ALL with intermediate and high risk were collected as control group, then the sensitive rate of patients to prednisone pretreatment, complete remission (CR) rate at day 33 after induction chemotherapy, relapse rate and 3-year event-free survival (EFS) were compared between T-ALL and B-ALL children. The results showed that no significant statistic difference were found in distribution of age, infiltration of liver, spleen and lymph nodes as well as central nervous system disease, chromosome abnormality, expression level of fusion gene and so on between T-ALL and B-ALL groups (p > 0.05), but there were significant differences in sex and number of cases with WBC count ≥ 50 × 10(9)/L between them (p < 0.05). The sensitive rate of T-ALL and B-ALL patients to prednisone pretreatment was 51.9% and 89.3% respectively (p < 0.05). The ratio failed to achieve CR at day 33 after induction chemotherapy was 15.4% and 8.1% in the two groups (p > 0.05). The relapse rate of T-ALL and B-ALL cases was 30.8% (8/26) and 14.9% (11/74) respectively (p > 0.05). The time from CR to relapse was (9.78 ± 3.48) month and (21.28 ± 14.32) month (p < 0.05). The 3 year EFS of T-ALL cases with intermediate and high risk was (37.5 ± 17.1)% and (22.2 ± 9.8)%, while 3 year EFS of B-ALL cases was (66.7 ± 7)% and (51.7 ± 9.3)% respectively (p < 0.05) according to Kaplan-Meier survival curve. It is concluded that as compared with B-ALL cases, the male ratio and initial WBC count are higher, moreover the early response to prednisone pretreatment and 3 year EFS are poor in T-ALL cases, the prognosis outcome is poor also.

[Effects of long-term application of organic fertilizer and superphosphate on accumulation and leaching of Olsen-P in Fluvo-aquic soil].

Based on a 20-year experiment of fertilization with organic and chemical fertilizers on a Fluvo-aquic soil under wheat-corn cropping system, this paper studied the relationships between Olsen-P concentration in plough layer and crop yields as well as the accumulation and vertical translocation of Olsen-P in soil profile. The results showed that when the Olsen-P concentration in plough layer maintained at 10-40 mg x kg(-1), the grain yields of wheat and corn were higher, whereas when the concentration of Olsen-P in plough layer was higher than 40 mg x kg(-1), it started to leach, which meant that in light loam Fluvo-aquic soil, the threshold value for P leaching might be 40 mg x kg(-1). In the treatments of chemical fertilization (NPK) and corn straw returning (SNPK) with the P application rate of 77-90 kg x hm(-2), the Olsen-P concentration in plough layer was increased by 0.63-0.72 mg x kg(-1) per 100 kg x hm(-2) of applied P, with an annual increment of 0.49-0.65 mg x kg(-1) and needed 45-60 years for reaching the threshold value for P leaching. In the treatments of chemical fertilization combined with manure application (MNPK, MNPK2, and 1.5MNPK), the formula of Olsen-P accumulation in 0-20 cm soil layer were Y(MNPK) = 3.1097x + 6.9615 (R2 = 0.8562), Y(MNPK2) = 2.4765x + 13.563 (R2 = 0.9307), and Y1.5MNPK = 4.506x + 6.4464 (R2 = 0.8862). It might take 8 years to reach the threshold value for Olsen-P leaching when the P application rate in treatment 1.5MNPK was 210 kg x hm(-2), 11 years when the P application rate in treatments MNPK2 and MNPK was 125 and 140 kg x hm(-2). Organic fertilization combined with chemical fertilization increased the Olsen-P accumulation rate being 2.5 times higher than chemical fertilization. Excessive application of organic fertilizer could increase the accumulation and leaching of Olsen-P in soil profile.