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The liable organic carbon (LOC) plays an imperative role in soil fertility and rice production. The diverse crop rotations and straw returning appreciably improve the crop yield and soil health. Therefore, the present experiment was conducted from 2016 to 2017 comprising five treatments including winter fallow, winter Chinese milk vetch (CMV), winter rape, winter garlic, winter rotation-early rice-late rice to determine the impacts on liable carbon fractions and rice yield. The results showed that compared with the winter fallow treatment, except winter garlic treatment, all other winter cropping and double straw returning improved the soil organic carbon (SOC), total organic carbon (TOC) and microbial biomass carbon (MBC). However, water-soluble organic carbon (WSOC) content of winter CMV, rape, and garlic treatments decreased, but easily oxidizable carbon (EOC) and soil particulate organic carbon (POC) content of winter rotation treatment was increased. At the same time, organic carbon content in 0–15 cm soil was significantly higher than that in 15–30 cm soil layer (P < 0.05). The soil carbon pool management index (CPMI) of both earlier and late rice in the soil layer of winter treatment except 15–30 cm of winter garlic treatment was significantly improved and the CPMI was higher in 0–15 cm soil as compared to 15–30 cm. The two-year average yield of late rice was better than that of early rice and rice yield was positively correlated with TOC, WSOC and MBC, and negatively correlated with EOC and POC. In conclusion, different rotations and double straw returns improved LOC, which was conducive for improving yields of both early and late rice.

The struvite crystallization technology can recover nitrogen(N) and phosphorus(P) elements in the water. However, the presence of heavy metal ions affects the MAP crystallization process. Our work found a linear relationship between heavy metal ion (Zn2+/Cu2+/Pb2+) concentration as ln(C/C*) and kinetic rate constant Kt, which facilitates the optimization of the MAP process in waste effluents.

Winter cropping is an effective way to solve the low resource utilization efficiency in single rice system. In order to explore the effects of winter cropping on rice yield, economic benefits and resource utilization efficiency of single rice paddy field, two different cropping systems (single and winter multiple cropping systems) including 4 treatments: middle rice (CK), Chinese milk vetch—middle rice (DC), rape—middle rice (DR) and wheat—middle rice (DW) were set up to explore their difference on productivity, economic benefit and resource utilization efficiency. The results showed that compared with CK, the rice yield was increased by improving the components of rice yield and by increasing population dry matter accumulation in winter multiple cropping system. Compared with CK, the average annual yield of DC, DR and DW increased by 1.47%, 7.41% and 3.92%. The economic benefits of DR increased by 32.1% compared with CK, while the economic benefits of DC and DW were 9.99% and 8.3% lower than CK, respectively. Winter multiple cropping increased the light allocation rate. Compared with CK, DC, DR and DW increased light allocation rate by 119.25%, 102.11% and 104.39%, respectively, but the average annual light productive efficiency was 53.33%, 40.48% and 40% lower than CK. Winter multiple cropping increased the effective accumulated temperature distribution rate. Compared with CK, DC, DR and DW increased effective accumulated temperature distribution rate by 78.61%、58.8%、60.92%, respectively, but the average annual accumulated temperature (≥ 10℃) production efficiency was 43.11%、23.88%、24.04% lower than CK, respectively. Compared with the single cropping system, the double cropping system has significant advantages in annual rice yield, dry matter accumulation, total economic benefit, light and effective accumulated temperature distribution rate. Rape—middle rice model is the optimized planting model for the middle reaches of the Yangtze River.

Maize (Zea mayL.)–soybean [Glycine max(L.) Merr.] intercropping is popular in many countries because of its high productivity. However, no studies have explored maize–soybean intercropping via bibliometric methods. Taking the Web of Science database, the visualization applications of CiteSpace and VOSviewer were used to visually analyze the literature related to research in the field of maize–soybean intercropping, with the aim of studying keyword hotspots and evolving trends, and analyzing the future research directions. The results showed that the annual number of publications on maize–soybean intercropping showed rapid growth from 2010 to 2021. The top three publishing countries were China, the United States, and India, and the top three institutions were Sichuan Agricultural University, the Ministry of Agriculture and Rural Affairs of China, and China Agricultural University. Th three most popular journals were Field Crops Research, Agronomy Journal, and Indian Journal of Agronomy. Agronomy, multidisciplinary agriculture and plant science were the most popular research categories. A keyword analysis indicated that “maize” was the most popular study area. Crop root coupling processes, biological nitrogen fixation, efficient utilization of resources, carbon sequestration and emission reduction, microbial communities, and interspecific relationships are the current hot research topics. This study review and analyzed the current research hotspots and future research trends to provide an important reference for scientists to better respond to food security issues. There has been a rapid increase in maize–soybean intercropping research.China, Chinese institutions, and Chinese scholars have conducted much of this research.Maize–soybean intercropping has shown an interdisciplinary distribution.Keywords showed the heterogeneity in maize–soybean intercropping publications across years.

Straw retention and fertilization management can affect rice yield and greenhouse gas (GHG) emission in paddy field. To investigate the effect of leguminous green manure and straw retention plus nitrogen (N) fertilizer on rice yield and GHG emissions, field experiments were conducted from 2017 to 2018 and four treatments were designed, including the treatments of Chinese milk vetch (Astragalus sinicusL.) and rice (Oryza sativaL.) straw retention with reduced chemical N fertilizer application amount named RA (6000 kg hm−2rice straw plus 102 kg hm−2N fertilizer during early and late rice respectively), RB (6000 kg hm−2rice straw plus 87 kg hm−2N fertilizer during early and late rice season respectively), RC (6000 kg hm−2rice straw plus 72 kg hm−2N fertilizer during early and late rice season respectively) and control CK (winter fallow, without straw retention, 120 kg hm−2N fertilizer during early and late rice season respectively). The results showed treatments RA, RB, and RC significantly increased the early rice yield by 15.79, 21.27, and 13.60% (P< 0.05), and RA and RB significantly increased the annual yield by 14.76 and 15.79% (P< 0.05) compared with control CK. For CH4cumulative emissions, only RB had no significant impact on it (P> 0.05); treatments RA, RB, and RC had no significant effect on N2O cumulative emissions (P> 0.05). Meanwhile, treatments RA and RC significantly increased GWP and greenhouse gas emission intensity (GHGI) (P< 0.05) of CH4and N2O, but the difference between RB and control CK was not significant (P> 0.05). Therefore treatment RB had the best effect on rice production and GHG mitigation in paddy fields. Core IdeasStraw and vetch retention with reduced N fertilizer were studied on yield and GHGs in double‐cropped rice.Chinese milk vetch and rice straw retention plus reduced N fertilizer significantly increased rice yields compared with control.Effect of Chinese milk vetch and rice straw retention plus 87 kg of N fertilizer on GWP and GHGI was not obvious.Straw and vetch retention can help offset N fertilizer to increase yield and reduce costs, waste, and environment pollution. Straw and vetch retention with reduced N fertilizer were studied on yield and GHGs in double‐cropped rice. Chinese milk vetch and rice straw retention plus reduced N fertilizer significantly increased rice yields compared with control. Effect of Chinese milk vetch and rice straw retention plus 87 kg of N fertilizer on GWP and GHGI was not obvious. Straw and vetch retention can help offset N fertilizer to increase yield and reduce costs, waste, and environment pollution.

In order to obtain the crystalline forms of the salts of the potassium, ammonium, calcium coexisting chloride system, the phase equilibria relationship of quaternary system K+, NH4+, Ca2+//Cl–-H2O at 298.2, 323.2, and 348.2 K was studied by isothermal dissolution equilibrium method. The solubility and density of equilibrium liquid phases of the system were experimentally determined; X-ray powder diffractometer was used to determine the compositions of the equilibrium solid phase at the quaternary invariant point. It is found that the quaternary system is a complex system at these three temperatures. The phase diagram at 298.2 K consists of three invariant points, seven univariate curves and five crystalline phase regions, forming the solid solutions (NH4Cl)x(KCl)1–xand (KCl)x(NH4Cl)1–x; while at 323.2 and 348.2 K the phase diagram consists of five invariant points, eleven univariate curves and seven crystalline phase regions, the double salts (KCl·CaCl2) and (2NH4Cl·CaCl2·3H2O), solid solutions (KCl)x(NH4Cl)1–xand (NH4Cl)x(KCl)1–xwere formed. Among them, the crystalline phase region of solid solution (KCl)x(NH4Cl)1–xis the largest at three temperatures, indicating that it is the easiest to crystallize in this system. Comparing the phase diagrams of the quaternary system at 298.2, 323.2, and 348.2 K, it can be seen that the crystalline form of CaCl2changes with the increase of temperature: CaCl2·6H2O at 298.2 K, CaCl2·2H2O at 323.2 and 348.2 K. From 323 to 348 K, the crystalline phase regions of (KCl·CaCl2) and (2NH4Cl·CaCl2·3H2O) increased gradually.

A significant problem associated with the commercial acceptance of biodiesel is poor oxidative stability. This study investigated the effectiveness of individual and binary antioxidants to improve the oxidative stability of different types of biodiesel and distilled biodiesel. Results indicate that different types of biodiesel have different levels of oxidative stability, and that natural antioxidants and FAME composition play significant roles in determining oxidative stability. Synthetic antioxidants can enhance the oxidative stability of different types of biodiesel, and antioxidant activity increases as a function of its concentration. However, the effective activity level of antioxidant is dependent on biodiesel feedstock. Binary antioxidant formulations (TBHQ and PY) have a synergistic effect on oxidative stability of biodiesel. After long‐term storage at room temperature, the oxidative stability of untreated SBO‐based biodiesel significantly decreases as a function of time, while the addition of the antioxidant TBHQ can improve and maintain oxidative stability of biodiesel over an 18‐month period. However, the effectiveness of PY significantly decreases even after 2‐months.

Objective: To compare the accuracy of four volume estimation models to actual tissue and organ volumes measured in the visible woman. Methods: Actual volumes were calculated from 1‐mm‐thick visible woman images that were segmented for five major components including subcutaneous and visceral adipose tissue across the 1730 available slices. Four available models resolved to two equations: truncated cone/truncated pyramid vs. two‐column/parallel trapezium. Between‐slice interval and initial slice were systematically varied when deriving component volumes using the two equations in four regions. Results: For each compartment and each between‐slice interval, the means of the two‐column model were always the same as the corresponding reference volumes, whereas those of the truncated cone model were smaller than the reference volumes. Similarly, the coefficient variation for the two‐column model was always smaller than for the truncated cone model. Discussion: The equation based on the parallel trapezium and the two‐column models is more accurate in estimating tissue volumes than the corresponding equation for truncated pyramid and truncated cone models. This finding has important implications for the volume calculations of imaging‐based body compartments such as adipose tissue.

A method of spatial modulation of magnetization using the RF pulse train is described for improved cardiac tagging. The method is based on a sinc-modulated RF pulse train in the presence of constant gradient. Such an RF pulse train yields a rectangular profile of saturated magnetization, and the bandwidth of the sinc envelope controls the width of the saturation tag. Compared to DANTE and SPAMM tagging techniques, this method offers sharper-edged tags and the ability to change the ratio of tag width to tag separation. The approach was implemented on a 9.4 T vertical bore NMR system and demonstrated with both phantom and in vivo mouse heart studies. Magn Reson Med 48:389–393, 2002. © 2002 Wiley-Liss, Inc.

A method of spatial modulation of magnetization using the RF pulse train is described for improved cardiac tagging. The method is based on a sinc-modulated RF pulse train in the presence of constant gradient. Such an RF pulse train yields a rectangular profile of saturated magnetization, and the bandwidth of the sinc envelope controls the width of the saturation tag. Compared to DANTE and SPAMM tagging techniques, this method offers sharper-edged tags and the ability to change the ratio of tag width to tag separation. The approach was implemented on a 9.4 T vertical bore NMR system and demonstrated with both phantom and in vivo mouse heart studies. Magn Reson Med 48:389–393, 2002. © 2002 Wiley-Liss, Inc.

A method of spatial modulation of magnetization using the RF pulse train is described for improved cardiac tagging. The method is based on a sinc‐modulated RF pulse train in the presence of constant gradient. Such an RF pulse train yields a rectangular profile of saturated magnetization, and the bandwidth of the sinc envelope controls the width of the saturation tag. Compared to DANTE and SPAMM tagging techniques, this method offers sharper‐edged tags and the ability to change the ratio of tag width to tag separation. The approach was implemented on a 9.4 T vertical bore NMR system and demonstrated with both phantom and in vivo mouse heart studies. Magn Reson Med 48:389–393, 2002. © 2002 Wiley‐Liss, Inc.

Magnetic resonance imaging (MRI) has potential as an instrument to measure body composition because it can discriminate various soft tissues in vivo. These soft tissues include adipose tissue, muscle, organs, and brain. We report on preliminary studies using a 4.2-tesla MRI for measuring body composition in the mouse and rat. We employed image segmentation methods that include an image correction method, a necessary requirement when the images are taken in the presence of nonuniform radio-frequency (RF) coil response. The software for 3-D data segmentation, quantification, correction, image manipulation, and visualization has been developed as a research tool. This method currently is being validated.

Traumatic brain injury frequently causes traumatic axonal injury (TAI) in white matter tracts. Experimental TAI in the corpus callosum of adult mice was used to examine the effects on oligodendrocyte lineage cells and myelin in conjunction with neuroimaging. The injury targeted the corpus callosum over the subventricular zone, a source of neural stem/progenitor cells. Traumatic axonal injury was produced in the rostral body of the corpus callosum by impact onto the skull at the bregma. During the first week after injury, magnetic resonance diffusion tensor imaging showed that axial diffusivity decreased in the corpus callosum and that corresponding regions exhibited significant axon damage accompanied by hypertrophic microglia and reactive astrocytes. Oligodendrocyte progenitor proliferation increased in the subventricular zone and corpus callosum. Oligodendrocytes in the corpus callosum shifted toward upregulation of myelin gene transcription. Plp/CreERT:R26IAP reporter mice showed normal reporter labeling of myelin sheaths 0 to 2 days after injury but labeling was increased between 2 and 7 days after injury. Electron microscopy revealed axon degeneration, demyelination, and redundant myelin figures. These findings expand the cell types and responses to white matter injuries that inform diffusion tensor imaging evaluation and identify pivotal white matter changes after TAI that may affect axon vulnerability vs. recovery after brain injury.

Using a new magnetic resonance method that separately estimates the two principal forms of storage iron, ferritin and hemosiderin, in the heart, we examined the relationship between myocardial storage iron fractions and left ventricular function in thalassemia major. In patients with iron overload, the amount of iron in functional and transport pools changes only slightly. Virtually all of the excess is sequestered in storage forms of iron, as ferritin, a diffuse, soluble fraction, and as hemosiderin, an aggregate, insoluble fraction. The two storage forms of iron strongly affect signal intensity in both T2 and T2* weighted images but influence MRI signal decay through different means because of their differences in solubility and in intracellular distribution (Magn Reson Med2002; 47:1131–8). Separate estimates of the iron concentrations of the two forms of storage iron may be obtained by measuring two distinct relaxation parameters, the “ferritin iron index” (“reduced” transverse relaxation rate) RR2, and the “hemosiderin iron index”, A. We studied 14 patients with thalassemia major, all being treated with subcutaneous deferoxamine. Study participants were examined with a Philips 1.5 T Intera scanner using three Carr-Purcell-Meiboom-Gill (CPMG)-like multi-echo spin echo sequences with varied inter-echo times, using electrocardiographic triggering and respiratory navigator gating to estimate RR2 and A. The left ventricular shortening fraction was measured using standard echocardiographic methods. The Figure shows the relationship (R=0.91, p<0.0001) between the ferritin index, RR2, and the left ventricular shortening fraction. Figure Figure Overall, variation in the ferritin index explained more than 80% of the variation in ventricular function. For comparison, variation in the hemosiderin index, A, accounted for only about 33% of the variation in shortening fraction. Using an empirical calibration to estimate iron concentrations, variation in total (ferritin + hemosiderin) iron accounted for only about 40% of the variation in ventricular function. In patients with thalassemia major, the concentration of ferritin iron may provide a better indicator of the magnitude of the toxic iron pool than the total storage iron concentration. Magnetic resonance determinations of the partition of storage iron between ferritin and hemosiderin may be clinically valuable in evaluating tissue iron toxicity in patients with transfusional iron overload.

Using a new magnetic resonance method that separately estimates the two principal forms of storage iron, ferritin and hemosiderin, in the heart, we examined the relationship between myocardial storage iron fractions and left ventricular function in thalassemia major. In patients with iron overload, the amount of iron in functional and transport pools changes only slightly. Virtually all of the excess is sequestered in storage forms of iron, as ferritin, a diffuse, soluble fraction, and as hemosiderin, an aggregate, insoluble fraction. The two storage forms of iron strongly affect signal intensity in both T2and T2* weighted images but influence MRI signal decay through different means because of their differences in solubility and in intracellular distribution (Magn Reson Med 2002; 47:1131–8). Separate estimates of the iron concentrations of the two forms of storage iron may be obtained by measuring two distinct relaxation parameters, the “ferritin iron index” (“reduced” transverse relaxation rate) RR2, and the “hemosiderin iron index”, A. We studied 14 patients with thalassemia major, all being treated with subcutaneous deferoxamine. Study participants were examined with a Philips 1.5 T Intera scanner using three Carr-Purcell-Meiboom-Gill (CPMG)-like multi-echo spin echo sequences with varied inter-echo times, using electrocardiographic triggering and respiratory navigator gating to estimate RR2and A. The left ventricular shortening fraction was measured using standard echocardiographic methods. The Figure shows the relationship (R=0.91, p<0.0001) between the ferritin index, RR2, and the left ventricular shortening fraction.