Effects of Long-Term Bare Fallow During the Winter-Wheat Growth Season on the Soil Chemical Properties, Fungal Community Composition, and the Occurrence of Maize Fungal Diseases in North China.

On the North China Plain, one of the most water-deficient regions in China, bare fallow has been implemented over a large-scale area to conserve water during the growth season of water-intensive winter wheat since 2015. However, the effects of this bare fallow on fungal community and the occurrence of crop diseases are poorly understood. Here we measured soil chemical properties, fungal community composition, and the occurrence of crop diseases after 15 years of long-term fallow (continuous maize or soybean) and non-fallow (maize-wheat rotation; soybean-wheat rotation) cropping systems. Bare fallow during the winter-wheat growth season significantly decreased soil organic matter, available nitrogen, and phosphorus. It also changed the composition of soil fungal communities, i.e., increased relative abundances of some potentially pathogenic species of Lectera, Fusarium, and Volutella but decreased beneficial Cladorrhium and Schizothecium. Meanwhile, the epidemic tendency of maize diseases changed correspondingly: the disease index of southern corn leaf blight and maize brown spot increased, but the incidence of stalk rot decreased compared with the non-fallow system. Soybean diseases were very mild regardless of the cropping system during the total experimental period. Network analysis demonstrated that the soil fungal diversity associated with maize diseases was affected by the decreased soil organic matter and available nitrogen and phosphorus. Our results suggest that bare fallow in the winter-wheat season affected the soil chemical properties, fungal community, and the occurrence of maize fungal diseases.

Flow evaluation of STA-MCA bypass using quantitative ultrasonography: An alternative to standard angiography for follow up of bypass graft.

PURPOSE: To date, digital subtraction angiography (DSA) has been considered as the gold imaging modality for assessing graft patency after extracranial-intracranial bypass. The utility of a noninvasive and quantitative method of assessing graft flow postoperatively was evaluated by using quantitative ultrasonography. METHOD: All STA-MCA bypass surgery performed over a 5-year period at a single institution were reviewed. Measured by duplex ultrasonography, pre-operative (day1) and post-operative (day1, day7, 3month and 6 month) graft blood flow rates were recorded and analyzed. Results were correlated to Matsushima grade determined by DSA performed within 24 h when ultrasonography was conducted to confirm the graft function. RESULTS: 100 patients with 131 operated hemispheres were included in this study. The mean flow rates in the STA graft on pre-operative day1, post-operative day 1 and 7, at 3- and 6-month postoperatively were 24.1, 106.7, 112.6, 97.4 and 79.7 ml/min respectively. The mean post-operative flow in the STA graft graded as A/B/C were significantly different (168.0 ± 34.8 ml/min, 91.0 ± 15.5, 42.1 ± 17.2 ml/min, respectively, p = 0.000). 124.5 ml/min and 65.5 ml/min are good cut-off value for predicting post-operative graft Matsushima grade. The analysis also showed excellent agreement between ultrasonography and DSA for assessing bypass function (κ = 0.78). CONCLUSIONS: The patency of the STA grafts can be assessed noninvasively by quantitative ultrasonography, which results are comparable to those of conventional DSA. This, therefore, suggest that quantitative ultrasonography may be an alternative method to standard DSA for serial follow up of STA grafts.

[Differences in hydraulic erosion processes of the earth and earth-rock Lou soil engineering accumulation in the Loess Region]. / é»„åœŸåŒºåœŸè´¨ä¸ŽåœŸçŸ³è´¨å¡¿åœŸå †ç§¯ä½“æ°´åŠ›ä¾µèš€è¿‡ç¨‹å·®å¼‚.

An indoor rainfall simulation experiment was conducted to examine the hydrodynamic characteristics, erosion characteristics, and erosion dynamics mechanisms of earth (excluding gra-vel) and earth-rock (gravel mass fraction 30%) Lou soil engineering accumulation in the Loess area across different rainfall intensities and slope gradients. Results showed that the presence of gravel changed the hydrodynamic characteristics of the engineering accumulation slope. The flow velocity, froude number, unit stream power, and unit energy of water-carrying section of the earth-rock slope were 1.7%-49.7%, 6.7%-60.6%, 2.0%-44.6% and 1.0%-26.7% lower than those of the earth slope, while the Manning roughness coefficient and runoff shear stress of the earth-rock slope were 6.2%-169.4% and 5.7%-79.3% higher than those of the earth slope respectively. Under the intensity of 2.0 and 2.5 mm·min-1, erosion rate of the earth-rock slope was 26.2%-89.9% lower than that of earth slope. The gravel significantly reduced slope erosion of the Lou soil engineering accumulation. Erosion rate and hydrodynamic parameters of the two accumulations were linearly related. The erodibility parameters of earth-rock slope were 56.1%-73.3% lower than that of earth slope. In the critical hydrodynamic parameters, runoff shear stress of earth-rock slope was 11.1% higher, while the stream power, unit stream power and unit energy of water-carrying section were 25.4%, 64.0% and 5.0% lower than those of the earth slope, respectively. The existence of gravel controlled rainfall erosion process on the slope of the engineering accumulation to some extent.

Monitoring of Fusarium Species and Trichothecene Genotypes Associated with Fusarium Head Blight on Wheat in Hebei Province, China.

To clarify the changes in field populations of Fusarium head blight (FHB) pathogens over a decade, Fusarium species and trichothecene genotypes associated with FHB on wheat were monitored in Hebei province during the periods 2005-2006 and 2013-2016. Fusarium species determination was carried out by morphological identification, species-specific amplification and partial translation elongation factor (TEF-1α) gene sequencing. Trichothecene genotype prediction was carried out by primers 3CON/3NA/3D15A/3D3 or Tri13F/Tri13R, Tri303F/Tri303R and Tri315F/Tri315R. A total of 778 purified Fusarium isolates were recovered from 42 sampling sites in 17 counties during the period 2005-2006 and 1002 Fusarium isolates were recovered from 122 sampling sites in 65 counties during the period 2013-2016. F. graminearum was the predominant pathogen recovered during the periods 2005-2006 and 2013-2016. However, the pathogen composition differed slightly between the two periods. In 2005-2006, 752 out of 778 (96.7%) of the isolates belonged to F. graminearum. Two were identified as F. culmorum. Five other Fusarium species were also recovered, F. equiseti, F. verticillioides, F. proliferatum, F. subglutinans and F. chlamydosporum, with lower recoveries of 0.4%, 0.8%, 0.8%, 0.1% and 1.0%, respectively. Trichothecene genotype prediction showed that all the 752 F. graminearum isolates were of the 15-ADON genotype. Five Fusarium species were recovered from samples collected over the period 2013-2016. F. graminearum was again the predominant pathogen with an isolation frequency of 97.6%. F. pseudograminearum, F. asiaticum, F. culmorum and F. negundis were also isolated at a recovery of 1.4%, 0.7%, 0.2% and 0.1%, respectively. For the 2013-2016 isolates, 971 of the 978 F. graminearum strains were 15-ADON whereas seven isolates were of the 3-ADON type. All seven F. asiaticum isolates were of the NIV type and fourteen F. pseudograminearum isolates were classified as 3-ADON. F. pseudograminearum was first isolated from FHB in Hebei in 2013. Although the recovery of F. pseudograminearum is still low, it represents a small shift in the pathogen composition and trichothecene genotypes associated with FHB in Hebei province. As Fusarium crown rot of wheat caused by F. pseudograminearum is an increasing problem in Hebei province, it is appropriate to monitor the role of F. pseudograminearum in FHB in the future.

Intensity of Left Atrial Spontaneous Echo Contrast as a Correlate for Stroke Risk Stratification in Patients with Nonvalvular Atrial Fibrillation.

The intensity of left atrial spontaneous echo contrast (LASEC) by transesophageal echocardiography (TEE) has been proposed as an important variable in the stratification of thromboembolic risk, particularly in patients with nonvalvular atrial fibrillation (NVAF). We hypothesized that the quantification of LASEC by ultrasound will improve its utility in predicting subsequent stroke events in patients with NVAF. Patients (n = 206) with definite NVAF receiving TEE were included for this prospective cohort study. Baseline clinical risk factors of stroke, CHADS2 score and CHA2DS2-Vasc, left atrial thrombus (LAT), the five-grades of LASEC and video intensity (VI) value of LASEC were measured. During 2 years follow-up, 20 patients (9.7%) developed stroke. VI value of LASEC in the patients with stroke was higher compared to patients without stroke (25.30 ± 3.61 vs. 8.65 ± 0.81, p < 0.001). On logistic regression analysis, LAT, qualitative LASEC, graded LASEC, VI value of LASEC and CHADS2 and CHA2DS2-Vasc score were independent predictors of stroke. Among them, the highest area under the curve of receiver operating characteristic (ROC) in predicting stroke was VI value of LASEC (p < 0.05). These results show that quantification of LASEC by VI value is the most favorable predictor of stroke in patients with NVAF, and calls for improving the utility of LASEC in predicting subsequent stroke events.

[Research Progress of Silk Fibroin As a Drug Delivery Materials].

Recently, drug delivery materials have become the hotspot of medical study. Suitable delivery material plays an important role in constructing an excellent drug delivery system. Silk fibroin is a naturally occurring protein polymer with excellent biocompatibility, remarkable mechanical properties, biodegradability and outstanding processability. Due to its unique properties, silk fibroin has become a favorable carrier material for the incorporation and delivery of a range of therapeutic agents. Based on the structure and characteristics of silk fibroin, this article provides an overview of the recent research progress of silk fibroin used as drug delivery materials.

[Detection of binding capability of targeted KDR ultrasound contrast agent in vitro for evaluating endometrial receptivity].

OBJECTIVE: To prepare a new targeted liposome ultrasonic contrast agent with anti-KDR antibody that binds specifically with KDR as the main receptor of VEGF and evaluate its physical characteristics, biological activity and specific binding capability in vitro. METHODS: A sonicator was used to prepare the biotinylated lipid micro-bubbles (MB-B), and biotin-avidin-mediated technique was used for attachment of anti-mouse KDR monoclonal antibody to the micro-bubble shell to generate MB-BAB-KDR. MB-BAB-KDR was incubated with fluorescent second antibody to assess the link condition, and the control groups were the MB-B and micro-bubbles with the antibody alone (MB-B-KDR). A parallel plate flow chamber system was used to characterize micro-bubbles attachment efficiency to KDR Fc. RESULTS: The surface of the micro-bubbles could carry KDR antibody through the biotin-avidin bridge and MB-BAB-KDR were spherical and well-distributed. After incubation with the second antibody, MB-BAB-KDR could be observed to emit bright green fluorescence (Grade II) as compared with little or weak fluorescence in the control MB-B group (Grade 0) and MB-B-KDR group (Grade I). Targeted micro-bubbles bound to KDR Fc increased as the KDR Fc concentration increased (P<0.05). CONCLUSION: The targeted liposome contrast agent linked with KDR antibody by biotin-avidin bridge we prepared shows an increased binding number as the KDR Fc concentration increases, which provides a novel approach to molecular imaging study of endometrial receptivity.

[Echocardiographic evaluation of pressure overload-induced cardiac remodeling in mice using different ultrasound machines].

OBJECTIVE: To compare the results of echocardiographic evaluation of pressure overload-induced cardiac remodeling in mice using different ultrasound machines. METHODS: Eighteen C57 BL/6 mice were randomly divided into the sham-operated and the transverse aortic constriction (TAC) groups (n=9). Eight weeks after the operation, the cardiac function of TAC group was evaluated using Siemens ultrasonic instrument with 15L8 probe and the differences between the awake and anesthetized states were compared. The heart rate, left ventricular (LV) dimensions, systolic and diastolic functions were measured in both sham-operated and TAC groups using the Siemens ultrasonic instrument and a high-resolution ultrasonic imaging system for small animals (Vevo 770). RESULTS: Compared with the mice in wakefulness, the anesthetized mice showed significantly decreased heart rate and LV fractional shortening (P<0.001) and markedly increased LV end diastolic diameter and LV end systolic diameter (P<0.05). Both machines sensitively detected the cardiac remodeling of TAC mice in comparison with the sham-operated group. Compared with Siemens machine, Vevo 770 provided a higher resolution of 2D and M mode echocardiography with clearer Doppler frequency image of the mitral valve flow for evaluation of the LV diastolic function. CONCLUSION: Both machines are suitable for evaluating cardiac remodeling induced by pressure overload independent of anesthesia, though anesthesia depresses cardiac function. Vevo 770 is optimal to evaluate LV diastolic function in mice.

Late-phase detection of recent myocardial ischaemia using ultrasound molecular imaging targeted to intercellular adhesion molecule-1.

AIMS: in this study, we attempted to detect a recent myocardial ischaemic event using ultrasound molecular imaging (UMI) with microbubbles (MB) targeted to intercellular adhesion molecule-1 (ICAM-1) in the late phase of reperfusion. METHODS AND RESULTS: we created a myocardial ischaemia-reperfusion model in 60 C57/BL male mice to simulate an angina attack (ischaemia for 15 min, reperfusion for 1-24 h). The degree of myocardial inflammation and levels of ICAM-1 protein were determined by histological and immunohistochemical analyses. UMI with MB targeted to endothelial ICAM-1, as well as routine non-invasive methods including electrocardiography, echocardiography, and plasma troponin I levels, were utilized to evaluate ischaemia over the time course of reperfusion. Levels of ICAM-1 in the vascular endothelium were significantly increased over the time course of reperfusion (8-24 h) of the ischaemic myocardium. The video intensity of ICAM-1 molecular images of the ischaemic anterior wall was almost three times greater than that in the non-ischaemic posterior wall during the late phase (8-24 h) of reperfusion. In contrast, routine methods yielded only weak evidence of ischaemia. CONCLUSION: UMI with MB targeted to endothelial ICAM-1 provides reliable evidence of a recent myocardial ischaemic event in the late phase of reperfusion.

[Effect of polyethylene oxide on red blood cell velocity in rat cremaster microcirculation].

OBJECTIVE: To investigate the drag-reducing effect of polyethylene oxide (PEO) on the velocity of red blood cells in rat cremaster microcirculation. METHODS: Blood samples were collected from 6 Wistar male rats (100-110 g) via the post-orbital venous plexus. The red blood cells were separated by centrifugation and labeled by fluorescinisothiocyate (FITC). After successful establishment of cremaster model, the labeled red blood cells were injected into the jugular vein, and the microcirculation was observed and recorded under fluorescence microscope. The hemodynamic parameters and microcirculation video was recorded every 4 min since 4 min before PEO or normal saline injection. Both PEO (10 ppm) and normal saline was injected into the same rat in random sequence at a constant rate of 3.5 ml/h for 20 min followed by observation for another 20 min. The velocity of the labeled-red blood cells was determined by IPP 6.0 software. RESULTS: Compared with normal saline, PEO significantly increased the velocity of the red blood cells in the rat cremaster microcirculation (498.7-/+182.89 microm/s vs 773.54-/+308.27 microm/s, P=0.012). No significant changes in the heart rate and arterial blood pressure were observed during the experiment (P=0.836, P=0.420). CONCLUSION: PEO at an extremely low concentration can significantly increase the velocity of the red blood cells in rat cremaster microcirculation and produces no significant impact on heart rate and arterial blood pressure.

[Molecular imaging of thrombus with microbubbles targeted to alphavbeta3-integrin using an agarose flow chamber model].

OBJECTIVE: To assess the binding ability of microbubbles targeted to alphavbeta3-integrin (MBp) for thrombus-targeted contrast-enhanced ultrasound. METHODS: Targeted microbubbles were prepared by conjugating the monoclonal antibody against alphavbeta3-integrin to lipid shell of the microbubble via the avidin-biotin bridges. Equivalent isotype control microbubbles (MB) or targeted ultrasound microbubbles (MBp) were randomly added into the flow chamber. After a 30-min incubation with the thrombus fixed in an agarose flow chamber model, the thrombus was washed with a continuous flow of PBS solution (15 cm/s) for 2, 4, 6, 8 and 10 min, followed by thrombus imaging using contrast-enhanced ultrasound and measurement of the video intensity (VI) values of the images. RESULTS: The VI of the thrombus in MBp group was reduced by 28%-66%, while that in control MB group was decreased by 87%-94%, and the VI values of the thrombus group were significantly greater in former group at each of the time points (P<0.05). CONCLUSION: MBP has good targeting ability to the thrombus with resistance to the shear stress after adhesion to the thrombus. In vitro evaluation of the thrombus-binding capability of the targeted microbubble (MBp) by simulating the shear stress in vivo can be helpful for predicting the in vivo effects of ultrasonic molecular imaging using MBp.

[Evaluation of myocardial ischemia-reperfusion injury in mouse by molecular imaging of P-selectin with targeted contrast echocardiography].

OBJECTIVE: To assess the feasibility of evaluating myocardial ischemia-reperfusion injury in mouse with targeted myocardial contrast echocardiography (MCE). METHODS: Phospholipid microbubbles targeted to P-selectin (MBp) and control microbubbles (MBc) were created by conjugating monoclonal antibody against murine P-selectin or isotype control antibody with the lipid shell via "avidin-biotin" bridging. Ten mice with myocardial ischemia-reperfusion were injected intravenously of MBp and MBc in a random order with a 30 min interval. After 5 min of intravenous injection of microbubble, targeted MCE imaging was performed in all mice. And then the video intensity (VI) was determined. RESULTS: A significant ultrasonic enhancement was observed in ischemic region of MBp-group. Increment in VI value of ischemic region in MBp-group was great and it amounted to (26.0 +/- 6.2) U. However, increment in VI value of ischemic region in MBc-group was minor and it was merely (9.1 +/- 0.9) U. Difference was evident in ischemic region between of two groups (P < 0.05). In both MBp-group and MBc-group, the VI value of ischemic region was significantly greater than that of non-ischemic region (6.5 +/- 1.0) U vs (6.4 +/- 0.8) U (P < 0.05). There was no obvious difference in the VI of non-ischemic region between two groups. CONCLUSION: Molecular imaging of P-selectin with targeted contrast echocardiography can effectively evaluate myocardial ischemia-reperfusion injury.