BACKGROUND:A new type of medical titanium alloy Ti2448 (Ti-24Nb-4Zr-7.9Sn) is by far the lowest initial modulus of titanium alloy, with the initial modulus of about 40 GPa, the average Young's modulus<20 GPa, and tensile strength of about 900 MPa;human tissue biocompatibility and mechanical compatibility are excellent. OBJECTIVE:To investigate the biomechanical properties of a new low elastic modulus spinal pedicle screw fixation system and compare it with Ti6Al4V pedicle screw. METHODS:Totally 60 fresh human cadaveric thoracic vertebrae were randomly selected:on one side, pedicle new low modulus Ti2448 pedicle screws, as the experimental group;on the other side, pedicle screw Ti6Al4V, as control group. The maximum bending load and maximum load displacement, maximum torque and maximum axial pul ing force of the two groups were detected. RESULTS AND CONCLUSION:There was no significant difference in the maximum bending load, maximum load displacement, maximum torque and maximum pulling force between the two groups. The results show that the maximum bending strength, the maximum torque and maximum pul out force in low elastic modulus of Ti2448 pedicle screw fixation system are consistent with the Ti6Al4V screws, which can meet the needs of internal fixation on spinal biomechanics strength.

As a commonly used non-contact flatness detection method, laser triangular detection method is designed with low cost, but it cannot avoid measurement errors caused by strip steel vibration effectively. This paper puts forward a dynamic flatness image processing method based on improved laser triangular detection method. According to the practical application of strip steel straightening, it completes the image pre-processing, image feature curve extraction and calculation of flatness elongation using digital image processing technology. Finally it eliminates elongation measurement errors caused by the vibration.

Objective To investigate the imaging features and the relationship with pathological characteristics of chromophobe cell renal carcinoma (CCRC).Methods The clinicopatholocal manifestations and CT or MRI imaging findings were analyzed retro-spectively in 23 patients with surgically confirmed CCRC.The location,shape,size,density,border,blood supply and invasion of adjacent organs of CRCC,especially the dynamic enhanced mode,were mainly analyzed and compared with pathology.Results The 23 cases of CCRC showed unilateral single mass on CT and MRI scans,and 12 located in right kidney while 1 1 in left kidney.The size ranged from 27-330 mm in diameter,and round or oval-shaped soft tissue mass was observed.The boundaries of 1 6 cases were clear,and 3 cases of mass broke through renal capsule,3 invaded renal pelvis,perirenal fat,renal vein and inferior vena cava,2 ca-ses with retroperitoneal lymph node metastases.18 cases were scanned by CT and the mass presented as soft tissue density on plain CT (CT value 30-44 HU).6 cases were scanned by MRI with abnormalities presenting with iso or hypo-intense on the T1 WI,hy-per or hypo-intense on the T2 WI,and 2 cases of pseudocapsule were showed as circled hypointense on T2 WI.According to the dy-namic enhancement,23 cases of CCRC were divided into three type:(1 )Mild-to-moderate enhanced type(n= 14):including mild homogeneous strengthening (n=7)and mild heterogeneous strengthening (n=7);(2)Significantly enhanced type(n=7):including heterogeneous enhancement(n=6)and uniform enhancement(n=1);(3)Spokes shape or scar enhancement(n=2).The sample of CCRC was mainly solid and showed yellowish-brown or brown section.According to the situation of HE staining,the characteristic microscopic features were divided into three types:the typical,acidophil type and mixed type.Conclusion Combined imaging find-ings of CT dynamic enhanced mode can provide characteristic information for diagnosis of CCRC,and comprehensive analysis of the imaging findings will contribute to the diagnosis and differential diagnosis.

Objective To introduce a new method for correcting prominent malar complex deformity. Methods Through an intraoral incision, the highest area of zygomatic body marked preoperatively was grinded. Then an L shape incomplete osteotomy of the zygomatic body was performed with a reciprocating saw, and a complete osteotomy just 1 cm anterior to the articular tubercle of the zygomatic arch was made. Light pressure on the posterior part of the arch produced a greenstick fracture of the anterior osteotomy site, resulting in posterior-inward repositioning of the malar complex. Internal fixation was unnecessary. Results Operative procedures for reductive malar complex plasty were performed in 650 cases, which included 60 males and 590 females whose age ranged from 19 to 39 years.Incisions of all cases healed well. One case had maxillary sinusitis 2 weeks postoperatively, and recovered after 1 week by using antibiotics and drainage. There was 1 case with skin necrosis about 1 cm in diameter in the area of zygomatic body because of local liposuction, and the wound was healed by changing dressing. The forehead wrinkle of one side had disappeared in 1 case 1 week postoperatively, but had recovered 2 weeks later. Postoperative follow-up for 2-24 months showed satisfactory results.Conclusions This modified method has many advantages, such as simplicity, without internal fixation, short operation and recovery time, and little complications. The authors conclude that this technique is an effective and safe method of reduction malarplasty.

Objective To investigate the reliability of using the pubic symphysis diastasis of 25 mm and anterior separation distance of sacroiliac joint to differentiate anteroposterior compression (APC) type Ⅰ and Ⅱ injuries as well as assess the injury severity.Methods A total of 11 (seven males and four females) fresh cadaver specimens with 22 hemipelvis were collected.The pelvic APC injury test models including fixed hemipelvis (restricted group) and unfixed hemipelvis (non-restricted group) were established,with 11 hemipelvis in each group according to the random number table method.Meanwhile the specimens were divided into male group (14 hemipelvis) and female group (eight hemipelvis),simulating APC type injury external rotation hemipelvis.The public symophysis interval and anterior interval of sacroiliac joint of the original pelvis,the pubic symphysis diastasis and anterior diastasis of sacroiliac joint after anterior tibiofibular ligament failure,as well as the affected pelvis ligament and sacral ligament injury were recorded and compared between the restricted and non-restricted groups,male and female groups.Results There were no significant differences in the public symphysis interval of the original pelvis and anterior interval of sacroiliac joint between the restricted group and the non-restricted group (P ＞ 0.05).The pubic symphysis interval of the original pelvis was [(5.13 ± 0.61) mm] in male group and (4.03 ± 0.84)mm] in female group (P ＜ 0.05).When the anterior tibiofibular ligament ruptured,the pubic symphysis diastasis distance was (23.36 ± 7.27) mm,ranging from 12 to 41 mm,and the diastasis distance of anterior sacroiliac joint was (9.82 ± 3.25)mm,ranging from 5 to 18 mm.In terms of the public symphysis interval,there were no significant differences between male and female groups,restricted and the non-restricted groups (P ＞ 0.05).In terms of anterior interval of sacroiliac joint,there was significant difference between male and female groups (P ＜ 0.05) but no significant difference between the restricted and non-restricted groups (P ＞ 0.05).In the restricted group,sacrotuberous ligament injuries were found in four patients,and sacrospinous ligament injuries in five,whhile there were no obvious sacrospinous ligament and sacrotuberous ligament injuries in non-restricted group.There were 10 specimens with the pubic symphysis diastasis ≥23.36 mm and 10 specimens with the diastasis distance of anterior sacroiliac joint ≥9.82 mm (46％),and there were 15 specimens with at least the pubic symphysis interval ≥ 23.36 mm or the anterior interval of sacroiliac joint ≥ 9.82 mm (68％).Conclusions The public symphysis interval ≥ 23.36 mm or anterior interval of sacroiliac joint ≥ 9.82 mm can distinguish anteroposterior compression Ⅰ from Ⅱ injuries,and the combination of the two criteria can be beneficial to assessment of pelvic injury severity.

Objective To establish a three-dimensional finite element model of pelvic anteroposterior compression (APC) for analysis of mechanisms for related liganentous damages.Methods A finite element model and a laboratory mechanical model of APC were established using the same pelvic specimens.In a finite element model of normal pelvic bones and ligaments,after the right pelvis was fixated the pubic symphysis (PS) was sectioned.Next,a manual external mobile force was gradually applied to the left hemipelvis to make the PS diastasis 10,20,30,40,60,80 and 100 mm apart.The mechanical experiment revealed the anterior sacroiliac ligament (ASIL) was ruptured when the PS diastasis reached 28 mm.After the strain value of ASIL was calculated through the finite element model,it was applied to the other pelvic ligaments.The displacement in front of the sacroiliac joint (SIJ),stress,strain and extent of injury and disruption of sacrotuberous/sacrospinous ligaments (STL/SSL) with a corresponding PS diastasis were observed and recorded.Results ASIL failed at the point when the PS diastasis was 28 mm and the displacement in front of SIJ was 7.41 ± 1.14 mm.The strain and maximum principal stress of ASIL calculated in the finite element model were 259.5％ and 543.24 MPa respectively.The maximum principal stress value of SSL was 35.00 MPa at the point of failure when the PS diastasis and the displacement in front of SIJ were 51 mm and 15.23 ±2.88 mm,respectively.When the PS diastasis and the displacement in front of SIJ were 100 mm and 7.5 mm respectively,the maximum principal stress value of STL was 16.17 MPa but the strained ligament was not ruptured.When the pelvis was rotated externally step by step,the ASIL failure was followed by the rupture of SSL but not necessarily by the STL failure.Conclusion As the finite element pelvic bone-ligament model established in this study can effectively simulate the mechanisms for APC injury,it can be used to evaluate different extents of pelvic ligamentous injury,providing a basis for the biomechanical study of pelvic bones and ligaments.

Objective: To investigate adolescent haze weather health protection behavior, and to provide scientific basis for behavioral intervention and health guidance for adolescents in haze weather. Methods: From June 2015 to April 2016, 1 025 adolescents were selected from 22 classes in two middle schools of Baoding City, Hebei Province, by stratified cluster sampling method. General information questionnaire and the Brief Haze Weather Health Protection Behavior Assessment Scale Adolescent Version (BHWHPBAS AV) were used. Multiple linear regressions were conducted to explore factors affecting adolescent haze weather health protection behavior. Different models were used to confirm associations between influencing factors and BHWHPBAS AV scores. Results: Adolescents had a low overall score of BHWHPBASAV (45.81±13.16). The score rate of self adjustment after haze weather was the highest (64.54%). The score rate of obtaining relevant knowledge before haze weather was the lowest (50.28%). Compared with adolescents in urban area, rural adolescents had a lower BHWHPBAS AV score ( β=-3.20, P <0.01). Compared with students (living with parents), those living without parents had a lower BHWHPBAS AV score ( β=-4.16, P =0.01). Compared with students never receive physical examination,those had received physical examination during the past years had a higher BHWHPBAS AV score ( β=4.44，5.66，9.04, P <0.01). Compared with students with no knowledge of respiratory system diseases, those with moderate to sufficient knowledge had a higher BHWHPBAS AV score ( β=9.34，12.19，P <0.01). These associations were stable and consistent.Multiple linear regression analysis showed that residence, residence with parents, physical examination and knowledge of respiratory diseases were the relevant factors of BHWHPBAS AV score ( P <0.05). Conclusion Adolescent haze weather health protection behavior level is low and is affected by many factors. Cooperation should be strengthened to conduct behavioral interventions and health guidance on haze health protection for adolescents, so as to promote healthy growth of adolescents.

Objective To analyze how enterovirus D68 (EV-D68) protease 2A affects the anti-vi-ral interferon typeⅠ(IFN-Ⅰ) pathway in 293T cells following infection. Methods Western blot was used to detect the expression of recombinant protease 2A, IFN-α and signal transducers and activators of tran-scription 1 (STAT1) at protein level. Expression of EV-D68 viral protein (VP1) and protease 2A was ana-lyzed by immunofluorescence at different time points. Cytopathic effects were recorded to calculate 50％ cell culture infective dose ( CCID50 ) . Expression of the genes involved in the anti-viral IFN-Ⅰ pathway was measured by real-time PCR (RT-PCR). Results The recombinant plasmid pCLIPf-2A was successfully constructed and the expression of recombinant protease 2A could be detected by Western blot 24 h after transfection. The recombinant protease 2A promoted the proliferation of EV-D68 at the late stage of infection and induced the production of IFN-α. Expression of the genes involved in the anti-viral IFN-Ⅰ pathway at mRNA level was up- or down-regulated to different degrees with various trends in different groups following infection. Expression of STAT1 was enhanced in all groups. Conclusions EV-D68 protease 2A promoted the activation of anti-viral IFN-Ⅰpathway in response to viral infection and enhanced the proliferation of virus at the late stage of infection.

Objective:To investigate the long-term survival and safety in patients with muscle-invasive bladder cancer (MIBC) who experienced a noninvasive down-staging (≤pT 1)after transurethral resection of bladder tumor (TURBT) plus systemic chemotherapy and received bladder-sparing treatment. Methods:The records of patients with MIBC who underwent maximal TURBT plus systemic chemotherapy-guided bladder-sparing treatment were reviewed retrospectively from Dec 2013 to Dec 2020. Eventually, 22 patients who achieved noninvasive down-staging underwent conservative management. The total patient cohort contained 10 males and 12 females. A majority of patients had single lesion and stage T2 disease. The median age of the patients was 66 years and the median tumor size was 3.0 cm. All patients underwent maximal TURBT to resect all visible diseases and followed by 3-4 cycles platinum-based systemic chemotherapy. After achieving noninvasive down-staging, 14 patients received concurrent chemoradiotherapy, and the other 8 patients underwent surveillance. Overactive bladder symptom score (OABSS) was used to assess the bladder function after treatment.Results:Twelve patients achieved pT 0 and 10 patients were down-staged to cT a-T 1. At a median follow-up of 36.7 months, 90.9%(20/22) patients retained their bladder function successfully. Among the 14 patients who received concurrent chemoradiotherapy, 4 had grade 3 or 4 adverse events. Among the 8 patients who underwent surveillance, 3 had grade 3 or 4 adverse events after systemic chemotherapy.Nine patients experienced tumor recurrence in the bladder, and 2 patients died of bladder cancer. Seven (31.8%) patients experienced Ⅲ/Ⅳ grade complications. The 5-year recurrence-free survival (RFS) and overall survival (OS) in patients achieved pT0 were 66.7% and 100.0%, respectively. The 5-year RFS and OS in patients achieved cTa-T1 were 40% and 72%, respectively. The OABSS score of 20 patients who retained their bladder successfully was (1.00±1.03). Conclusions:MIBC patients who achieved noninvasive down-staging might be candidates for the bladder-sparing treatment with maximum TURBT followed by systemic chemotherapy.The patients who achieved pT 0 might have better prognosis with functional bladder.

Purpose: Reduced quality of life after cystectomy has made bladder preservation a popular research topic for muscle-invasive bladder cancer (MIBC). Previous research has indicated significant tumor downstaging after neoadjuvant chemotherapy (NAC). However, maximal transurethral resection of bladder tumor (TURBT) was performed before NAC to define the pathology, impacting the real evaluation of NAC. This research aimed to assess real NAC efficacy without interference from TURBT and apply combined modality therapies guided by NAC efficacy. Materials and Methods: Patients with cT2-4aN0M0 MIBC were confirmed by cystoscopic biopsy and imaging. NAC efficacy was assessed by imaging, urine cytology, and cystoscopy with multidisciplinary team discussion. Definite responders (≤ T1) underwent TURBT plus concurrent chemoradiotherapy. Incomplete responders underwent radical cystectomy or partial cystectomy if feasible. The primary endpoint was the bladder preservation rate. Results: Fifty-nine patients were enrolled, and the median age was 63 years. Patients with cT3-4 accounted for 75%. The median number of NAC cycles was three. Definite responders were 52.5%. The complete response (CR) was 10.2%, and 59.3% of patients received bladder-sparing treatments. With a median follow-up of 44.6 months, the 3-year overall survival (OS) was 72.8%. Three-year OS and relapse-free survival were 88.4% and 60.0% in the bladder-sparing group but only 74.3% and 37.5% in the cystectomy group. The evaluations of preserved bladder function were satisfactory. Conclusion After stratifying MIBC patients by NAC efficacy, definite responders achieved a satisfactory bladder-sparing rate, prognosis, and bladder function. The CR rate reflected the real NAC efficacy for MIBC. This therapy is worth verifying through multicenter research.