[The application of three-dimensional printing technique combined with three-dimensional reconstruction in mandibular fracture]

Objective:To explore the value and significance of the combination of 3D printing and spiral CT three-dimensional reconstruction in the diagnosis and treatment of common mandibular fractures. Method:Forty patients with mandibular fracture were collected. They were randomly divided into traditional operation group and 3D printing combined with three-dimensional reconstruction operation group. The differences between the two groups were compared according to the operation time and the recovery of fracture. Result:The operation time and trauma of 3D printing combined with three-dimensional reconstruction group were significantly better than those of traditional operation group, and the former was better than the latter （P<0.05）. Conclusion: 3D printing combined with three-dimensional reconstruction operation method realized the concept of individualized, precise and minimally invasive comprehensive treatment, which is worthy of clinical promotion.

P4696Short- and long-term follow-up of 1024 Children with transcatheter closure of ventricular septal defects: A Single center Study

Objective

To investigate the safety, efficacy and long-term prognosis of pediatric patients after percutaneous ventricular septal defect (VSD) closure.

Method

A total of 1024 children with VSD in were enrolled. All children underwent transthoracic echocardiography (TTE), electrocardiogram (ECG) and chest roentgenogram before and after the treatment. Follow-up evaluation was done at 1, 3, 6, 12 months.

Results

1. 40 of 1024 patients gave up TC after angiography. Successful closure of VSD was achieved in 94.9% (934/984).

2. The defect were successfully occluded in 934 children. 939 VSD devices were implanted, 5 patients received 2 occluders. The average diameter of occluder was 6.40±2.13mm (3.00–18.00mm), and the mean operation time was 86.81±41.85min (30.00–360.00min).

3. Short postoperative complications were as follows: diffuse subarachnoid hemorrhage (1/934, 0.11%), high or complete atrioventricular block (1/934, 0.32%), mechanical hemolysis occurred (18/934, 1.93%). Moreover, the conduction disturbances included complete left bundle branch block (15/934, 1.61%), incomplete right bundle branch block (144/934, 15.42%), borderline rhythm (48/93, 45.14%), and complete right bundle branch block (44/934, 4.71%), left anterior branch block (27/934, 2.89%), premature contraction (21/934, 2.36%), ST-T segment changes (12/934, 1.28%).

4. The follow-up time ranged from1 to 192 months with the median time 36 months (12, 60) and the follow-up rate was 84.1% (795/934). There was no difference of mean left ventricular size between normal outpatients and patients accepted TC for more than 10 years (4.50±0.30cm V.S. 4.57±0.35cm, t=1.171, P=0.251).

5. New complications included III°AVB (1 case), CLBBB (1 case), ARs (27 cases) and residual shunt (12 cases). The operation age, the distance from defect to valve, the occluder diameter, the asymmetrical occluder and follow-up duration were associated risk factors of AR (OR= 4.107, 5.30, 3.824, 6.750, 9.625, P=0.033, 0.015, 0.045, 0.020, 0.000, respectively). The difference of occluder diameter, defect size and follow-up time were related risk factors of residual shunt (OR=7.000, 5.417, 11.333, 29.250, P=0.012, 0.037, 0.031, 0.000, respectively).

6. The patients were divided into 4 groups (∼3 years group, 3 ∼ 4 years group, 4∼ 6 years group, and 6∼ 18 years group. No significant differences of the success rate, defect size, operation time, incidence rate of short- and long-term complications rate. There was significantly difference of short complications incidence rate in 4 groups (c2=23.431 P=0.000).

Conclusions

The TC has a high successful rate in the pediatric patients with VSD. Patients with CLBBB or III°AVB can return to normal in the early stage after operation, but may recur during follow-up period. There is no significant difference in the successful rate and the incidence rate of long-term complications between patients <3 years and children ≥3 years old.

Acknowledgement/Funding

Taishan scholars (no. ts201511099)

Long-term decomposed straw return positively affects the soil microbial community

AIMS

In order to understand the response of soil microbial communities to the long-term of decomposed straw return, the modifications of soil microbial community structure and composition induced by more than 10 years of fresh and decomposed straw return was investigated and the key environmental factors were analysed.

METHODS AND RESULTS

Phospholipid fatty acid analysis and high-through sequencing technique were applied to analyse the structure and composition of the soil microbial communities. Compared with fresh straw, returning decomposed straw increased the relative abundance of bacteria and fungi by 1·9 and 7·7% at a rate of ~3750 kg ha^-1 , and increased by 23·1 and 5·7%, at a rate of ~7500 kg ha^-1 respectively. The relative abundance of the bacteria related to soil nitrification increased, but the ones related to soil denitrification decreased with decomposed straw return, which led to higher total nitrogen contents in soils. Moreover, returning decomposed straw reduced pathogenic fungal populations (genus of Alternara), which had significantly positive correlation with soil electric conductivity. It indicated that the long-term of decomposed straw return might have lower risk of soil-borne disease mainly for the reasonable soil salinity.

CONCLUSIONS

Long-term of decomposed straw return could provide suitable nutrient and salinity for healthier development of soil microbial community, both in abundance and structure, compared with fresh straw return.

SIGNIFICANCE AND IMPACT OF THE STUDY

The results of the study helps to better understand how the microbial community modifications induced by decomposed straw return benefit on soil health. The obtained key factors impacting soil microbial community variations is meaningful in soil health management under conditions of straw return.

Orbital-dependent charge dynamics in MnP revealed by optical study

Unconventional superconductivity often emerges at the border of long-range magnetic orders. Understanding the low-energy charge dynamics may provide crucial information on the formation of superconductivity. Here we report the unpolarized/polarized optical conductivity study of high quality MnP single crystals at ambient pressure. Our data reveal two types of charge carriers with very different lifetimes. In combination with the first-principles calculations, we show that the short-lifetime carriers have flat Fermi sheets which become gapped in the helimagnetic phase, causing a dramatic change in the low-frequency optical spectra, while the long-lifetime carriers are anisotropic three-dimensional like which are little affected by the magnetic transitions and provide major contributions to the transport properties. This orbital-dependent charge dynamics originates from the special crystal structure of MnP and may have an influence on the unconventional superconductivity and its interplay with helimagnetism at high pressures.