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ObjectiveFarmland consolidation for agricultural mechanization in hilly and mountainous areas can alter the landscape pattern, elevation, slope and microgeomorphology of cultivated land. It is of great significance to assess the ecological risk of cultivated land to provide data reference for the subsequent farmland consolidation for agricultural mechanization. This study aims to assess the ecological risk of cultivated land before and after farmland consolidation for agricultural mechanization in hilly and mountainous areas, and to explore the relationship between cultivated land ecological risk and cultivated land slope.MethodsTwenty counties in Tongnan district of Chongqing city was selected as the assessment units. Based on the land use data in 2010 and 2020 as two periods, ArcGIS 10.8 and Excel software were used to calculate landscape pattern indices. The weights for each index were determined by entropy weight method, and an ecological risk assessment model was constructed, which was used to reveal the temporal and spatial change characteristics of ecological risk. Based on the principle of mathematical statistics, the correlation analysis between cultivated land ecological risk and cultivated land slope was carried out, which aimed to explore the relationship between cultivated land ecological risk and cultivated land slope.Results and DiscussionsComparing to 2010, patch density (PD), division (D), fractal dimension (FD), and edge density (ED) of cultivated land all decreased in 2020, while meant Patch Size (MPS) increased, indicating an increase in the contiguity of cultivated land. The mean shape index (MSI) of cultivated land increased, indicating that the shape of cultivated land tended to be complicated. The landscape disturbance index (U) decreased from 0.97 to 0.94, indicating that the overall resistance to disturbances in cultivated land has increased. The landscape vulnerability index (V) increased from 2.96 to 3.20, indicating that the structure of cultivated land become more fragile. The ecological risk value of cultivated land decreased from 3.10 to 3.01, indicating the farmland consolidation for agricultural mechanization effectively improved the landscape pattern of cultivated land and enhanced the safety of the agricultural ecosystem. During the two periods, the ecological risk areas were primarily composed of low-risk and relatively low-risk zones. The area of low-risk zones increased by 6.44%, mainly expanding towards the northern part, while the area of relatively low-risk zones increased by 6.17%, primarily spreading towards the central-eastern and southeastern part. The area of moderate-risk zones increased by 24.4%, mainly extending towards the western and northwestern part, while the area of relatively high-risk zones decreased by 60.70%, with some new additions spreading towards the northeastern part. The area of high-risk zones increased by 16.30%, with some new additions extending towards the northwest part. Overall, the ecological safety zones of cultivated relatively increased. The cultivated land slope was primarily concentrated in the range of 2° to 25°. On the one hand, when the cultivated land slope was less than 15°, the proportion of the slope area was negatively correlated with the ecological risk value. On the other hand, when the slope was above 15°, the proportion of the slope area was positively correlated with the ecological risk value. In 2010, there was a highly significant correlation between the proportion of slope area and ecological risk value for cultivated land slope within the ranges of 5° to 8°, 15° to 25°, and above 25°, with corresponding correlation coefficients of 0.592, 0.609, and 0.849, respectively. In 2020, there was a highly significant correlation between the proportion of slope area and ecological risk value for cultivated land slope within the ranges of 2° to 5°, 5° to 8°, 15° to 25°, and above 25°, with corresponding correlation coefficients of 0.534, 0.667, 0.729, and 0.839, respectively.ConclusionsThe assessment of cultivated land ecological risk in Tongnan district of Chongqing city before and after the farmland consolidation for agricultural mechanization, as well as the analysis of the correlation between ecological risk and cultivated land slope, demonstrate that the farmland consolidation for agricultural mechanization can reduce cultivated land ecological risk, and the proportion of cultivated land slope can be an important basis for precision guidance in the farmland consolidation for agricultural mechanization. Considering the occurrence of moderate sheet erosion from a slope of 5° and intense erosion from a slope of 10° to 15°, and taking into account the reduction of ecological risk value and the actual topographic conditions, the subsequent farmland consolidation for agricultural mechanization in Tongnan district should focus on areas with cultivated land slope ranging from 5° to 8° and 15° to 25°.

Both malignant tumors derived from gastrointestinal tract and metastasis from peritoneal spread, hematogenous dissemination and lymph node can lead to acute abdomen. Such acute abdomen patients have poor prognosis, high mortality, and complex clinical manifestations. It is difficult to make a correct diagnosis in clinical practice. Recent studies show that gastrointestinal tumors are associated with clinical emergency. Malignant gastrointestinal tumors mostly result in obstruction, so upper gastrointestinal contrast for gastric cancer and post-enhanced CT for colon cancer are recommended; gastrointestinal stromal tumors usually cause bleeding, so computed tomography angiography (CTA) is the first choice for examination; primary gastrointestinal lymphoma tends to cause perforation and usually occurs in small intestine, so CT is the first examination for patients with ischemic acute abdomen, and post-enhanced CT is essential to exclude small intestine carcinoid because of its rising incidence in recent years. The possibility of gastrointestinal metastasis should be kept in mind for patients with cancer presenting acute abdomen. This article focuses on the imaging features of common gastrointestinal tumors and their acute obstruction, perforation, and hemorrhage, and aims to improve the understanding of such symptoms in clinical practice so that correct diagnosis and treatment can be made in time.

Neoadjuvant chemoradiotherapy (NCRT) combined with total mesorectal excision (TME) has become the recommended standard treatment strategy for local advanced rectal cancer (cT3 or cN+). After neoadjuvant chemoradiotherapy, preoperative T/N re-staging and efficacy evaluation of rectal cancer are directly related to the available treatment options and prognosis, so they are the common questions concerned by physicians. At present, magnetic resonance imaging (MRI) is acknowledged to be one of the more effective and feasible methods of T/N re-staging and efficacy evaluation, especially in the molecular microscopic scale. The diffusion weighted imaging (DWI) can reflect the movement of water molecules outside the tumor cells, and the multi-phase dynamic contrast enhanced MRI (DCE-MRI) can indirectly reflect the permeability of tumor vascular wall and local blood perfusion of tumor from the view of pathophysiological point. Because of the influence of edema, inflammatory response and fibrous tissue proliferation after radiotherapy, scholars both at home and abroad increasingly pay more attentions to the accuracy of T/N re-staging and efficacy prediction in MRI following neoadjuvant therapy. In this review, we elucidate the application value and limitation of MRI based on T/N re-staging and local efficacy evaluation.

Objective: To evaluate the performance of intravoxel incoherent motion (IVIM) diffusion-weighted MR imaging in the differential diagnosis of Angiomyolipoma (AML), clear cell renal cell carcinoma (clear cell RCC) and non-clear cell renal cell carcinoma (non-clear cell RCC)., Method: Forty-five patients were enrolled and classified into three groups according to the surgical pathology results. There were even amount of subjects (15) in each group of AML group, clear cell RCC group and non-clear cell RCC group (including 6 Papillary RCC and 9 Chromophobe RCC). ALL the patients underwent respiratory-triggered DWI on 3.0T MR system using multi b-values of 0, 20, 50, 100, 150, 200, 400, 600, 800 sec/mm2. Pure molecular-based (D), perfusion-related (D*) and vascular fraction (f) were calculated using a bi-exponential model. Comparisons of derived parameters derived by IVIM-DWI among three groups were performed using One-way ANOVA., Results: D in clear cell RCC (1.8±1.5)×10(-3) mm2/s was significantly higher than that in AML (0.7±0.3)×10(-3) mm2/s or non-clear cell RCC (0.9±0.3)×10(-3) mm2/s (P<0.05), while no statistical difference was observed between AML and non-clear cell RCC (P=0.807). D* demonstrated significant difference between AML (33.3±18.2)×10(-3) mm2/s and non-clear cell RCC (17.8±17.3)×10(-3) mm2/s, (P<0.05). No observed significant difference in f was revealed between any two groups., Conclusion: Pure water molecules (true diffusion) and capillary microcirculation (pseudo-diffusion) may result in the observed difference of parameters in these three types of renal tumors. D value can contribute to differentiate the clear cell RCC from AML, and between clear cell and non-clear cell RCC as well. D* value may be applied to differentiate AML from non-clear cell RCC.

Objective: To evaluate the changes of ADC value on renal parenchyma at different age groups in healthy adults., Methods: One hundred healthy adults were divided into five groups based on age:namely 18-29 years, 30-39 years, 40-49 years, 50-59 years and 60-69 years. All adults underwent diffusion-weighted magnetic resonance(MR) imaging of the kidneys with b values of 800 s/mm(2). ADC values of renal parenchyma were measured by the manufacturer's software., Results: With the increasing of age , the renal parenchyma ADCs decrease. The ADCs of renal parenchyma in five age groups were (2.07 ± 0.10) ×10(-3)mm(2)/s, (2.06 ± 0.12) ×10(-3)mm(2)/s, (2.03 ± 0.10) ×10(-3)mm(2)/s, (1.98 ± 0.17) ×10(-3)mm(2)/s and (1.94 ± 0.12) ×10(-3)mm(2)/s, which had statistically significant different (F = 3.375, P < 0.05)., Conclusion: (1)The ADCs of renal parenchyma may be influenced by age , with the increasing of age, ADCs of normal kidney presented tenuous decreasing tendency especially the people aged ≥ 40 years; (2)in clinical application, we ought to pay attention to the influence of age factor. Income data of this study can be took as normal reference value in other more study.

Objective: Series of complicated molecule signal pathway are involved in the bone regeneration. To explore the possibility of nuclear factor kappa B (NF-kappaB) which is taken as the "key activation" during the fracture healing and provide the laboratory evidence for the gene therapy of nonunion or delayed union of fractures., Methods: Thirty-three adult male Wistar rats (weighing 180-220 g) were selected and divided randomly into 4 groups: group A (the control group, n=3), the rigth lower segments of radius were injected with normal saline 0.3 mL for 7 days, once per day; group B (Bay 11-7082 injection group, n=6), the middle and distal radius were injected with normal saline containing 50 pmol/L NF-kappaB inhibitor Bay 11-7082 0.3 mL for 7 days, once per day; group C (fracture group, n=12), the right middle and distal radius were cut by a sharp scissors to form per fracture model; and group D (Bay 11-7082 treatment group, n=12), based on group C, 0.3 mL of 50 micromol/L Bay 11-7082 were injected into the fracture site for 7 days, once per day. The callus tissues were harvested at 3, 7, 14, and 28 days after fracture for Western blot analysis, alkaline phosphatase (ALP) activity assessment, prostaglandins E2 (PGE2) production assay, and histological observation., Results: The rats of all groups were survival till the experiment completion. At 3 and 7 days after injection, there was no significant difference in the ALP activity and PGE2 production between group B and group A (P > 0.05); but group C was significantly higher than group A (P < 0.01) and group D was significantly lower than group A (P < 0.01). The expressions of NF-kappaB p65, bone morphogenetic protein 7 (BMP-7), and inhibitor of DNA binding 2 (Id2) were observed at fracture sites of 4 groups. There was no significant difference in the expressions of NF-kappaB p65, BMP-7, and Id2 between group B and group A (P > 0.05); the expressions of NF-kappaB p65 and BMP-7 were significantly higher and the expression of Id2 was significantly lower in group C than group A (P < 0.01); and the expressions of NF-kappaB p65 and BMP-7 were significantly lower and the expression of Id2 was significantly higher in group D than group A (P < 0.01). The histological observation showed that a lot of osseous callus formed in group C at 14 and 28 days., Conclusion: but osseous callus just began to form in group D at 28 days. NF-kappaB p65 can facilitate early fracture healing of rat radius by elevating the PGE2 production and regulating BMP-7 and Id2 expression.

Objective: To study the changes of blood flow of the already-compressed cauda equina under dynamic burden, high frequency stimulation (HFS) and increased additional compression, and to clarify the mechanism of neurogenic intermittent claudication., Methods: Thirty SD rats were divided into 5 groups, 6 in each. All groups were operated with laminectomy of the fifth lumbar verfebra. One hour after the measurement of blood flow, in 4 experimental groups, the silicon sheets were inserted into the spinal canal of L4 and L6 to cause double level compression of cauda equina by 30%. Two hours after onset of compression, no dynamic burden was introduced to the subjects of the experimental group 1. Only HFS was introduced to the subjects of the experimental group 2 for 6 minutes. Both HFS and increased additional compression were introduced to the subjects of the experimental group 3 for 6 minutes. While only increased additional compression was introduced to the subjects of the experimental group 4 for 6 minutes. The subjects of control group only underwent laminectomy of the fifth lumbar vertebra and HFS 6 minutes. The blood flow of cauda equina was measured with laser Doppler flowmeter., Results: In the first 2 hours, there was no significant change of cauda equina blood flow in the control group. During the time of HFS, the blood flow increased significantly to 186.4% +/- 31.5% of initial value (P < 0.05). In the experimental group 1, there was no blood flow change during the period of dynamic burden(110.4% +/- 7.5%, P > 0.05). After introduction of dynamic burden, there was no blood flow changes in the experimental group 2 (111.6% +/- 17.6%, P > 0.05). The blood flow in the experimental group 3 decreased to 65.3% +/- 10.7% of initial value (P < 0.05); and the blood flow in the experimental group 4 decreased to 60.1% +/- 9.2% of initial value (P < 0.01). There was no significant difference between the experimental groups 3 and 4 (P > 0.05)., Conclusion: The results above show that during the period of increased impulse transmission, double level compression of cauda equina may limit the increase of blood flow, which may cause relative ischemia. If there is increased additional compression along with increased impulse transmission, the blood flow will decrease significantly, which will cause absolute ischemia.

Objective: To evaluate the results of laminoplasty and foraminotomy in treatment of cervical radiculopathy., Methods: Of 29 patients, there were 16 males and 13 females, aged 38 to 72 years with an average of 59 years. The reasons of intervertebral foramen stenosis were prolapse of intervertebral disc, osteophyte formation of Luschka joint, spinal canal stenosis combined with thickness of flavum ligmentum and facet joint hypertrophy. The most frequently affected intervertebral foramen were C5.6 and C6.7. The most significant symptoms after impairment of nerve root were reduced sensation, muscle weakness and diminished reflexes. On the basis of laminoplasty, the foraminotomy was performed on the stenotic foramen, including grade I decompression on 13 occasions, degree II on 21 occasions; and double level decompressions were performed on 5 patients., Results: After operation, reduced sensation was recovered most significantly and quickly, and the recovery of muscle weakness followed, while the recovery of diminished reflexes was the slowest and worst. In the followed-up patients, the percentage of excellent and good results was 97%., Conclusion: In the cervical spondylotic patients who also have foraminar stenosis, performing laminoplasty with foraminotomy can get good results. If the indication are chosen properly, it can be used widely in clinic.