[Determination Method and Characteristics of Particle Size Multiplier of PM2.5 in Road Dust].

The particle size multiplier is a valuable parameter for depicting the particle size distribution characteristics of road dust and calculating road dust emissions. In order to realize the localization of the particle size multiplier, the AP-42 and TRAKER methods were used for sampling on typical and different types of roads in Baoding in March 2019. Then, the particle size multiplier of road dust PM2.5 (K2.5) was calculated using the correction formula, and the characteristics were analyzed. The results indicated:① The K2.5 obtained separately by AP-42 and TRAKER were 0.21 g·VKT-1 and 0.23 g·VKT-1 on average, which correlated well, with a high correlation coefficient of 0.6. The PM2.5 emission factors calculated using the K2.5 of the different methods were almost at the same value, indicating that TRAKER method based on a laser sensor could measure and calculate the K2.5 and could be directly used to obtain the particle size multiplier or be converted using the fitting equation. ② The characteristics of the K2.5 in Baoding were ranked as:Expressway

[Validity study of Coda Motion Analysis System for measuring cervical lateral flexion in normal adults].

OBJECTIVE: To investigate the validity of Coda Motion Analysis System for measuring cervical lateral flexion in normal adults in order to explore a new measuring tool for clinical and research practice. METHODS: A total of 43 participants were involved in the study. Cervical range of lateral flexion were measured with Coda Motion Analysis System and "gold standard" X-ray simultaneously. The validity and agreement were assessed using the scatter diagram, the Pearson correlation coefficient and limits of agreement. RESULTS: Cervical range of lateral flexion measured by Coda Motion Analysis System had no statistical differences with those measured by X-ray(P>0.05). The Coda Motion Analysis System demonstrated a very good linear relation with the X-ray measurements in cervical range of right lateral flexion, left flexion and total lateral flexion, and the Pearson correlation coefficients were 0.72, 0.85 and 0.90 respectively. CONCLUSIONS: Coda Motion Analysis System showed good validity for measuring cervical lateral flexion in normal adults. Because the reliability of Coda Motion Analysis System was established previously, the results of this study suggest that the system has the potential to be used to measure cervical lateral flexion in clinical and research practice.

Ebselen protects mitochondrial function and oxidative stress while inhibiting the mitochondrial apoptosis pathway after acute spinal cord injury.

Ebselen is a fat-soluble small molecule and organic selenium compound that regulates the activity of glutathione peroxidase to alleviate mitochondrial oxidative stress and improve mitochondrial function. In the present study, we aimed to investigate the effects of ebselen on mitochondrial oxidative stress response, mitochondrial apotosis, and motor behaviors after spinal cord injury (SCI). We found that ebselen significantly increased the BBB score in motor behavior, thus suggesting a rescue effect of ebselen on motor function after SCI in rats. Meanwhile, we revealed that ebselen can increase glutathione (GSH) content as well as superoxide dismutase (SOD) and catalase (CAT) activities after SCI-this suggests ebselen has an antioxidant effect. Furthermore, the ATP content and Na+-K+-ATPase activity in mitochondria were increased by ebselen after SCI, while the mitochondrial membrane potential (MMP) was decreased by ebselen. The Cytochrome C and Smac release from mitochondria were reduced by ebselen after SCI, thus indicating improved membrane permeability by ebselen. Moreover, the alterations in caspase-3, Bax and Bcl-2 protein expression, as well as the proportion of cell apoptosis were improved by ebselen treatment, which together suggested that ebselen has an inhibitory effect on mitochondrial apotosis pathways after SCI. Taken together, our results suggest that ebselen can inhibit secondary damage caused by spinal cord injury. Indeed it plays a neuroprotective role in spinal cord injury perhaps by improving mitochondrial function and inhibiting the mitochondrial apoptosis pathway.

[Change of 3D cervical range of motion after single-level anterior cervical corpectomy and fusion].

OBJECTIVE: To study the change trend of cervical range of motion(ROM) after single-level anterior cervical corpectomy and fusion(ACCF) in treating cervical spondylotic myelopathy. METHODS: The clinical data of 23 patients with cervical spondylotic myelopathy was retrospectively analyzed from February 2015 to April 2016. There were 11 males and 12 females, with an average age of (54.6±13.3) years. All the patients were diagnosed as cervical spondylotic myelopathy by interrogation, physical examination and radiology, and were treated by ACCF. The Coda motion system was applied to assess the cervical range of motion pre-and post-operation. JOA and VAS scores were used to evaluate the clinical outcomes. RESULTS: The mean follow-up time was (9.4±1.6) months. Cervical ROM in all directions at 3 months postoperatively were significantly lower except for the left rotation(P<0.05). There was significant difference of cervical ROM in all directions between preoperative and 6 months postoperatively(P>0.05). The right lateral bending and the left rotation at 9 months postoperatively increased significantly(P<0.05). Postoperative extension at 6 months was significantly better than that of 3 months postoperatively(P<0.05). The extension, left and right lateral bending and left rotation at 9 months postoperatively were significantly better than of 6 months postoperatively(P<0.05). Postoperative JOA scores at each time points were significantly higher than that of preoperative(P<0.05) and VAS scores at each time points were significantly lower than that of preoperative(P<0.05). CONCLUSIONS: The change trend of three-dimensional cervical ROM after single-level ACCF revealed that the ROM decreased in short term, and later increased and was better than the preoperative level. Meanwhile, the neurological function improved significantly. But the short-term and long-term change trend of ROM postoperatively and the change trend of ROM after multi-level ACCF need to be further studied.

[Study of olfactory ensheathing cells transplantation and treadmill training on improving hindlimb motor function of spinal cord injury rats].

OBJECTIVE: To investigate the effects of olfactory ensheathing cells (OECs) transplantation and treadmill training in improving hindlimb motor function of spinal cord injury(SCI) rats and explore its possible mechanism. METHODS: A total of 80 male SD rats were randomly divided into four groups: media untrained (group A), OECs untrained (group B), media trained (group C) and OECs trained(group D). Each group had 20 rats and all rats were made the model of spinal cord injury. The rats of group C and D underwent treadmill exercise in 3 days after operation, the rats of group B and D underwent OECs transplantation in 7 days after operation (each rat was injected a total of 4 µl, cell concentration was 1.0×106/µl), at the same time, the rats of group A received the corresponding dose of saline. Then observed was continued for 4 weeks totally. BBB scores in each group were measured weekly. The expression of Bax, Bcl-2, NF-200 were observed by immunohistochemisty staining. Mallory staining was used to the regeneration of nerve fibers and TUNEL staining was used to observe neuronal apoptosis. RESULTS: (1)The BBB scores in group D in the 4th week was significantly higher than of other three groups(P<0.05). (2)On the Bcl-2 protein expression, there was interaction between OECs and treadmill training, the two mutually reinforcing;while OECs transplantation can significantly reduce the Bax protein expression without significant interaction with treadmill training(P>0.05). TUNEL staining showed that OECs transplantation, treadmill training, the time factor had an interaction and significantly inhibited the apoptosis(P<0.05). (3)It was showed in immunohistochemisty staining of NF-200 and Mallory staining that OECs transplantation, treadmill training with the time factor were an interaction among the three with significant regeneration of nerve fibers(P<0.05). CONCLUSIONS: OECs transplantation combined with treadmill training can significantly improve hindlimb motor function of SCI rats, which may be achieved by the following ways. OECs transplantation and treadmill training can collaborate with each other, significantly increasing the expression of Bcl-2 gene, which significantly inhibit neuronal apoptosis;at the same time it can promote neuronal axonal regeneration, increase the number of nerve fibers, and this effect may be more remarkable with time.

[Unilateral versus bilateral pedicle screw fixation in minimally invasive transforaminal lumbar interbody fusion(MIS-TLIF): a Meta analysis].

OBJECTIVE: To compare the clinical outcome between unilateral and bilateral pedicle screw fixation in minimally invasive transforaminal lumbar interbody fusion(MIS-TLIF) for the treatment of lumbar degenerative diseases. METHODS: The studies concerning unilateral or bilateral pedicle screw fixation in MIS-TLIF for the treatment of lumbar degenerative diseases from January 2000 to October 2015 were searched from Medline, Embase, The Cochrane Library, China Biology Medicinedisc and Wanfang database, China National Knowledge Internet (CNKI). The data of the studies were collected, risk of bias of the included RCTs were assessed according to Cochrane handbook 5.1.0, risk of bias of the included retrospective or prospective studies were assessed according to MINORS. The Oswestry Disability Index (ODI), visual analogue scale(VAS), lumbar lordosis angle, segmental lordosis angle, lumbar scoliosis angle, segmental scoliosis angle, fusion rate, complication rate, hospitalization time, operative time and blood loss data were Meta analyzed by RevMan 5.2.0 software. RESULTS: Nine studies were included, containing 4 randomized controlled trials (RCT), 2 prospective studies and 3 retrospective studies, there were 451 patients in total. The results showed that there was no significant difference between the two methods in VAS of back pain, VAS of leg pain, ODI, lumbar lordosis angle, segmental lordosis angle, lumbar scoliosis angle, segmental scoliosis angle, fusion rate, complication rate, hospitalization time. There was significant difference in operative time and blood loss between unilateral and bilateral pedicle screw fixation. CONCLUSIONS: Using unilateral or bilateral pedicle screw fixation in MIS-TLIF for lumbar degenerative diseases can achieve the same clinical effects, and there was no significant difference in complication rate. Unilateral pedicle screw fixation is safer than bilateral fixation because of less operative time and blood loss. However, the number and quality of the literatures may result in low reliability, so greater sample size and high quality RCTs are needed in future.

[Association between incidence of idiopathic ventricular tachycardia and risk factors with short-term effects: a case-crossover study].

OBJECTIVE: To explore the transient risks regarding idiopathic ventricular tachycardia (IVT). METHODS: A symmetric bidirectional case-crossover design was used to estimate the short-term risk of IVT. In the case-crossover design each case served as its own matched control while case-period were compared to two control-periods, 7 days before and after the case-period. Ninety-four subjects were recruited from People's Hospital of Jiangsu Province and Affiliated Hospital of Southeast University from Dec. 2007 to Nov. 2008. Generalized estimating equation, with binomial distributed dependent variable and logit link-function, was used to estimate OR and 95%CI. RESULTS: The risk factors that were associated with IVT would include: physical exertion (OR = 2.20, 95%CI: 1.51 - 3.19), in the state of anger (OR = 1.87, 95%CI: 1.07 - 3.27) sad feelings (OR = 3.58, 95%CI: 2.19 - 5.84), or agitation (OR = 3.06, 95%CI: 1.61 - 5.83) and having infection of some kind (OR = 2.25, 95%CI: 1.44 - 3.50). CONCLUSION: Factors as physical Exertion, in the mood of anger, sadness agitation, having some kind of infection were related to IVT. Case-crossover design seemed to be able to identify the risk factors of IVT and its intensity.