Objective:To investigate personal exposures to nitrogen oxides(NOX)and nitrogen di-oxide(NO2)and the influence of baseline personal characteristics,living environment and daily activity patterns of the participants on the exposures among adults over 35 in Tianjin and Shanghai.Methods:In this panel study,91 healthy nonsmoking adults aged over 35 from Tianjin and Shanghai participated in our study.The study was conducted in summer and winter.The participants were followed for three times with an interval of at least two weeks.Only participants in Shanghai were followed once in winter because of the COVID-19 pandemic.Twenty-seven participants completed follow-up visits in both seasons.We measured their 24 h personal exposures to NOX and NO2and collected their baseline and time-activity in-formation through questionnaire/diary.The linear mixed model was used to analyze the associations be-tween potential influencing factors and personal NOX and NO2 exposure levels.Results:There were 349 follow-up visits with valid 24 h personal NO2 and NOX exposure measurements in the two cities.The ave-rage 24 h personal exposures to NO2 and NOX(volume fraction)in Tianjin participants were 18.0 x 10-9 and 26.2 × 10-9 in summer,and 31.0 x 10-9 and 54.9 x 10-9in winter,respectively;and the average 24 h personal exposures to NO2 and NOX in Shanghai participants were 38.7 x 10-9and 100.0x10-9in summer,and 45.5 x10-9 and 139.2 x 10-9 in winter,respectively.The results of univariate regression analysis showed that their personal NOX exposure levels were significantly associated with city,season,gender,average daily cooking times,and ambient NO2 concentrations measured at fixed-site monitoring stations.In addition to the above factors,the personal NOX exposure levels were also significantly associ-ated with educational level and the personal NO2 exposure levels were also significantly associated with passive smoking,average daily home time,cooking energy type,residential distance from main traffic road,and use of kitchen ventilators.Multivariate regression analysis showed that the personal exposure levels of NO2 and NOX were significantly lower in Tianjin than that in Shanghai,were significantly lower in summer than that in winter,and were significantly and positively associated with ambient NO2 concen-trations measured at fixed-site monitoring stations.In addition,personal NOX exposure levels were signifi-cantly lower in females than in males,and personal NO2 exposure levels were significantly positively asso-ciated with average daily cooking times and significantly inversely associated with average daily home time.For every interquartile range(IQR)increase(12.7 × 10-9)in ambient NO2,the personal NO2 exposure levels increased by 27.5％(95％CI:17.0％-38.9％),and personal NOX exposure levels in-creased by 16.1％(95％CI:7.1％-25.8％).Conclusion:Season,city and ambient NO2 concentra-tions are significant influencing factors of personal exposure levels of NO2and NOX At the same time,the personal exposures levels of NO2 are also affected by lifestyle factors.Our study provides scientific evi-dence for making precise air pollution control decisions and reducing the exposure levels of NOX in the population.

Objective:To explore the diagnosis and treatment of humeral medial epicondyle fracture combined with radial neck fracture in children and adolescents.Methods:The clinical data were retro-spectively analyzed of the 12 pediatric patients with fractures of the humeral medial epicondyle plus the radial neck who had been admitted from February 2015 to August 2021 to Department of Pediatric Orthopedics, The Second Hospital of Fuzhou. There were 6 males and 6 females, with an age of (11.1 ± 2.5) years. According to the Papavasiliou classification, the humeral medial epicondyle fractures were type Ⅱ in 7 cases, type Ⅲ in 2 cases and type Ⅳ in 3 cases; according to the Judet classification, the radial neck fractures were type Ⅰ in 3 cases, type Ⅱ in 4 cases and type Ⅲ in 5 cases. Two Judet-Ⅰ radial neck fractures were missed by X-ray exam-ination but diagnosed by CT examination. Of the humeral medial epicondylar fractures, 9 were treated by open reduction and hollow screwing and 3 by closed reduction and Kirschner wiring. Of the radial neck fractures, 8 were treated by closed reduction and elastic intramedullary nailing and 4 conservatively. Fracture healing was followed up by postoperative radiographs. At the last follow-up, the carrying angles were measured, Kim Elbow Function Score (KEPS) was used to evaluate the functional recovery of the injured limb, and related complications were recorded.Results:All the 12 patients were followed up for (40.0±25.6) months. Fractures headed after (6.3±1.2) weeks. At the last follow-up, the carrying angle was 15.5°±2.6° on the injured side and 14.7°±2.0° on the healthy side, showing no significant difference ( P>0.05); KEPS was (96.3±5.3) points on the injured side and (98.8±2.3) points on the healthy side, showing no significant difference either ( P>0.05). No incision infection, bone nonunion, elbow valgus, joint stiffness or other complications were found; the postoperative elbow stability recovered well. Conclusions:As the fracture of the humeral medial epicondyle combined with the radial neck fracture is a special type of injury of straightened elbow during valgus stress in children and adolescents, it is likely to be missed in diagnosis. The goal of treatment is good functional recovery by restoring the articular match and elbow stability.

Objective:To compare the operative treatment and non-operative treatment of the re-ruptured Achilles tendon with rupture end distance within 1 cm.Methods:We retrospectively analyzed 14 cases with Achilles tendon postoperative re-rupture in our hospital from May 2012 to March 2019. All 14 cases showed distance of rupture end less than 1cm during imaging in a passive plantarflexion position. Among the 14 cases with re-rupture, 8 were in the operative treatment group (7 males and 1 female, mean age 36.3±6.4 years, duration from initial rupture to re-rupture 3 to 213 weeks, height 174.9±8.7 cm, weight 75.5±13.9 kg, body mass index 24.5±2.7 kg/m 2, distance of re-ruptured ends 4.9±2.5 mm) and 6 were in the non-operative treatment group (5 males and 1 female, mean age 40.0±9.0 years, duration from initial rupture to re-rupture 4 to 60 weeks, height 173.8±3.5 cm, weight 77.5±7.4 kg, body mass index 25.7±2.5 kg/m 2, distance of re-ruptured ends 5.7±2.1 mm). The Achilles tendon rupture score (ATRS), visual analogue scale (VAS), and foot and ankle ability measure (FAAM) were used to evaluate the result at the patients' last follow-up. Results:All the 14 cases were followed for 8.7 to 92.2 months, with mean follow-up of 39.6 months. Ultrasound or MRI was performed at 6 months postoperatively or at last follow-up to ensure the Achilles tendons' healing. The average ATRS score, VAS score, FAAM-ADL score, and FAAM-Sports score of the operative treatment group were 85.4±13.5, 0 (0, 1.0) , 86.9±8.3, and 76.3±15.4, respectively. While those of the non-operative treatment group were 82.8±5.7, 0.5 (0, 1.3) , 88.1±8.3, and 77.2±15.0, respectively. The average VAS score, FAAM-ADL score, and FAAM-Sports score of the operative treatment group and those of the non-operative treatment group was not significantly different. The ATRS scores of 7 patients of the operative treatment group were between 81 and 96. The satisfaction rate of operative treatment group was 87.5% (7/8). The ATRS scores of 5 patients of the non-operative treatment group were between 81 and 91. The satisfactory rate of non-operative treatment group was 83.3% (5/6). All Achilles tendon re-rupture cases had no complications such as a third time Achilles tendon rupture or wound infection after treatment.Conclusion:For the re-ruptured Achilles tendon with rupture end distance within 1 cm, non-operative treatment achieved similar curative effect compared to operative treatment through extended duration of immobilization and non-weightbearing.

Objective:To measure and compare the geometric rotation axis of the talocrucial joint at different poses during the normal gait.Methods:The kinematic data of 15 healthy volunteers, 8 females, 7 males; age, 26.2±5.4 y (range 19-39 y); height, 170.4±6.9 cm (range 160-183 cm); mass, 65.6±14.0 kg (range 52-100 kg). They were collected using the dual-fluoroscopy technique, and the spatial position of the tibia and talus was determined using the 3D-2D registration method. The medial and lateral side of the trochlear of each talus was fitted by two spheres and the geometric rotation axis of the tibiotalar joint was defined as the line connecting the origins of two spheres. Compared the position and orientation of the axis for different poses during the gait and also compared the difference of the radius of the medial and lateral spheres fitting the trochlear of each talus.Results:The radii of the medial spheres fitting the trochlear of each talus 19.52±1.47 mm,were significantly less than that of the lateral spheres 20.62±1.49 ( t=7.081, P<0.05). The averaged anterior-posterior distance between the geometric rotation point of the tibiotalar joint were 1.54±1.84, 1.71±1.69, 1.70±1.57, 1.72±1.62, 1.80±1.75, 1.96±1.86 mm, respectively, while the averaged medial-lateral distance were 0.06±1.84, -0.03±1.83, 0.08±1.83, 0.10±1.73, 0.10±1.47, 0.09±1.46 mm, respectively, and the averaged superior-inferiordistance were -21.92±1.46, -22.10±1.32, -22.10±1.50, -22.06±1.64, -21.93±1.62, -21.98±1.50 mm, respectively. The averaged angle between the geometric rotation axis of the tibiotalar joint and coronal plane were 3.31°±2.48°, 3.10°±2.67°, 3.64°±2.71°, 3.96°±3.19°, 4.28°±2.82°, 4.16°±3.11°, respectively, while the averaged angle between that and sagittal plane were 84.11°± 2.42°, 83.77°±3.19°, 83.77°±3.45°, 83.81°±3.69°, 83.99°±2.97°, 84.23°±3.01°, respectively, and the averaged angle between that and transverse plane were 4.40°±2.93°, 4.54°±3.74°, 3.97°±3.34°, 3.73°±2.49°, 3.78°±2.76°, 4.48°±2.49°, respectively. The position and orientation of the geometrical rotation axis of the tibiotalar joint at different poses during the gait showed no significant difference ( P>0.05). The rotation axis orientated from laterally and inferiorly to medially and superiorly with an averaged inclination angle from the horizontal plane of 3.74° and an averaged deviation angle from the coronal plane of 4.15°. Conclusion:The geometric rotation axis of the tibiotalar joint was fixed during the gait, therefore fitting the talar trochlea with the two-sphere model with a small radius of the medial sphere and a large radius of the lateral sphere may better mimic the kinematics of tibiotalar joint.

Since its birth in the early 1990s, metabolic engineering technology has gone 30 years rapid development. As one of the preferred chassis for metabolic engineering, S. cerevisiae cells have been engineered into microbial cell factories for the production of a variety of bulk chemicals and novel high value-added bioactive compounds. In recent years, synthetic biology, bioinformatics, machine learning and other technologies have also greatly contributed to the technological development and applications of metabolic engineering. This review summarizes the important technological development for metabolic engineering of S. cerevisiae in the past 30 years. Firstly, classical metabolic engineering tools and strategies were reviewed, followed by reviewing systems metabolic engineering and synthetic biology driven metabolic engineering approaches. The review is concluded with discussing future perspectives for metabolic engineering of S. cerevisiae in the light of state-of-the-art technological development.
Computational Biology ; Metabolic Engineering ; Saccharomyces cerevisiae/genetics* ; Synthetic Biology

Objective: To setup a custom-made gait simulator, and to provide an efficient tool for biomechanics research of ankle and foot. Methods: From November 2017 to April 2018, a total of 6 fresh frozen specimens of the foot and ankle were collected. The donated specimens, free of diseases in the foot and ankle part, were from the Department of Anatomy, Shanghai Medical College of Fudan University. Donors were 3 males and 3 females, aged from 48 to 69 years old, with an average age of 58.8 years old. The nine tendons in the foot were divided into 4 bundles, including anterior group comprised of tibialis anterior (TA), extensor hallucis longus (EHL) and extensor digitorum longus (EDL). Posterior group comprised of Achilles's tendon (AT). Medial group comprised of tibialis posterior (TP), flexor hallucis longus (FHL), and flexor digitorum longus (FDL). Lateral group comprised of peroneus brevis (PB) and peroneus longus (PL). A custom-made gait simulator was set up by using four independent electro motors to actuate 4 bands of tendons in the foot and another six motors to control tibia to achieve 6 degree-freedom parallel mechanism. And a hydraulic machine was used to provide axial pressure along tibia. Gait cycle of six fresh frozen cadaver feet was reproduced using this machine, and the kinematics data of ankle movement and ground reaction force (GRF) data was collected. By comparing the data above with the normal human gait data, the simulation results were analyzed to explore the clinical usage of this machine. Results: On the sagittal plane, the ankle appeared to plantarflexion at the beginning of gait, and then turned to dorsiflexion after the max plantar flexion (about 10°) at 18% of gait cycle. At the 40% gait cycle, ankle joint was in neutral position and reached its max dorsiflexion (about 22°) at 83% gait cycle. On the coronal plane, ankle joint appeared inversion at the beginning and eversion afterwards with 10° range of change. On the horizontal plane, movement of ankle joint was small. Results showed that the first peak of vertical ground reaction force can reach to 1.1-1.3 times of bodyweight at 25% of gait cycle and the second peak appeared little lower at 70% of gait cycle. The GRF in posterior direction reached its peak at 30%, and then turned to anterior with its peak at 83% gait cycle. The GRF had small variation at the internal to external direction.All of the coefficients of multiple correlations (CMC) of GRF and ankle joint movements were close to or greater than 0.90. Conclusion This custom-made gait simulator has good gait simulation ability with high intra repeatability in respect of ankle rotation and ground reaction force, and can satisfy the request for ankle and foot biomechanics research.

Objective: To explore the mid-term efficacy of derotation of talus and medial column fusion for stage II-V Müller-Weiss disease (MWD). Methods: Data of thirty-six patients (38 feet) with MWD treated by derotation of talus and talona-vicular (TN) or talonavicular-cuneiform (TNC) arthrodesis in our center during January 2008 to December 2016 were retrospective-ly analyzed. There were 3 males (3 feet) and 33 females (35 feet) with an average age of 54.0±9.2 years old (range, 32-80 years old); there were 11 right feet and 27 left feet. According to Maceira and Rochera staging system, there were 9 stage II cases, 11 stage III cases, 10 stage IV cases and 8 stage V cases. The external rotation of talus was intensively focused. After the TN articular surface was debrided, an "H" shape plate and a hollow lag screw were used to firmly fix the TN or TNC joint. American Orthopae-dic Foot and Ankle Society Scale (AOFAS), visual analog scale (VAS) and relative radiological parameters were evaluated preoper-atively and during follow-up. Results: The mean follow-up duration was 37.2 months (range, 25-113 months). The latest follow-up showed satisfactory outcomes. Overall, AOFAS score was improved from 41.3±11.3 points (range, 20-56 points) preoperatively to 85.5±7.1 points (range, 68-100 points) postoperatively (Z=5.16, P< 0.001), and the VAS score was reduced from 5.6±1.5 points (range, 3-8 points) preoperatively to 0.8±1.2 points (range, 0-4 points) postoperatively (Z=5.19, P< 0.001). These differences of functional score and pain evaluation were statistically significant. The Tomeno-Méary angle decreased from-6.6°±12.2° to 0.5°±2.9° (Z=3.43, P=0.001); the calcaneal pitch angle increased from 13.5°±3.9° to 22.1°±3.4°(t=10.12, P< 0.001), and the talarnavic-ular coverage angle decreased from 27.1°±5.9° to 7.6°±3.3°(Z=5.16, P< 0.001). The AP talar-first metatarsal angle decreased from-16.0°±10.7° to-7.0°±8.5°(t=5.49, P< 0.001). The differences of radiological parameters were statistically significant. Conclusion The mid-term results showed that the TN or TNC joint fusion could achieve a favorable clinical and radiological outcome for MWD patients. Even for the patients with severe deformities (stage II-V), such treatment strategy could also achieve satisfacto-ry deformity correction and functional improvement. Intraoperative restoration of talus rotation is the key to normal alignment of the subtalar joint/TN joint.

Objective To propose a CT classification of die-punch fragments in posterior pilon fracture and to explore its significance in helping the surgery.Methods ACT scan classification of die-punch fragments in posterior pilon fracture into 5 types was proposed according to their size and location.A retrospective study was conducted of the 48 posterior pilon fractures which had been treated at Department of Orthopaedics,Huashan Hospital from January 2013 to December 2015.They involved 16 men and 32 women,aged from 20 to 87 years (average,46.5 years).According to the preoperative CT scan classification of die-punch fragments,16 cases (33.3％) belonged to type Ⅰ,2 (4.2％) to type Ⅱ,18 (37.5％) to type Ⅲ,10 (20.8％) to type Ⅳ and 2 (4.2％) to type Ⅴ.Choice of operative approach,reduction and internal fixation and removal of the fragments were guided by the CT classification of die-punch fragments.Their postoperative ankle functions were evaluated with American Orthopaedic Foot and Ankle Society (AOFAS) and visual analog scale (VAS) scoring systems.Results All the 48 cases were followed up for 11 to 21 months (average,13.7 months).Their AOFAS scores for ankle-hindfoot at the final follow-up ranged from 77 to 92 points,averaging 84.3 points;their VAS scores ranged from 0 to 1 point,averaging 0.2 point.There were no significant differences in their postoperative AOFAS scores for ankle-hindfoot or in their postoperative VAS scores between the types of die-punch fragments (P ＞ 0.05).No complications were recorded except superficial infection at the posteromedial wound of the ankle in 2 cases,tarsal tunnel syndrome in 2 cases,and sural nerve irritation in 2 cases.Conclusion It is feasible and effective to classify the die-punch fragments in posterior pilon fracture according to their size and location on the CT scan,because the classification can help choose an appropriate operative approach and manage the die-punch fragment,leading to fine clinical outcomes.

Objective Purpose of this research is to biomechanically compare the screw-fixed and plate-fixed posterior malleolus fracture in osteoporosis patients with fatigue loading system and space motion system in simulation gait cycle,and to give a theory evidence on how to choose an internal fixation in osteoporosis patients with posterior malleolus fracture.Methods 72 osteoporotic cadaveric lower limbs were prepared to simulate Haraguchi Ⅰ posterior malleolus fracture and randomized into 2 groups with 36 each.Screw group were fixed with 2 paralleled 4.0 mm titanium partial thread cancellous screws from posterior to anterior.Plate group were fixed with plate.Based on the ratio of fracture area on sagittal plane to distal tibial articular surface (S),the two groups were subdivided into three subgroups,named as screw group A,plate group A,screw group B,plate group B,screw group C,plate group C.S (screw group A,plate group A)=l/4;S (screw group B,plate group B)=1/3;S (screw group C,plate group C)=1/2.According to the height of fracture fragments,these 6 subgroups were further divided into subgroup "a" with height 19.3mm and subgroup "b" with height 39 mm.Furthermore,4 different conditions of gait cycle were simulated as follows:1) specimen was loaded with 3.2 body weight (BW) at dorsiflexion angle of 12°;2) Start-up phase:dorsiflexion angle of 5°,3 BW;3) neutral position,3.6 BW;4) maximum plantar flexion,angle of 12°,4.5 BW.At the end of repeated loading,the displacement of fracture fragment was measured with space motion system.Results At dorsiflexion 12° and plantar flexion 15°,there was a significant difference of displacement between screw and plate group with a larger displacement in screw group,whatever S or H was.When ankle was at dorsiflexion of 5°,the displacement showed significant difference between screw group Aa and plate group Aa,screw group Ba and plate group Ba,screw group Bb and plate group Bb,screw group Cb and plate group Cb,with a larger displacement in screw group.In neutral position,the differences were significant with a larger displacement in screw group,except between screw group Bb and plate group Bb.Conclusion Plate can provide stronger fixation for osteoporosis patients with posterior malleolus fracture in most situations,but both of the two methods cannot provide stable fixation when posterior malleolus fragment was in a too big area or height.

BACKGROUND: Operative correction of hallux valgus is one of the most procedures in foot and ankle department, but postoperative plaster slab immobilization often brings great inconvenience and pain. Off-loading forefoot shoes can theoretically help them to do activities off bed early, and prevent loading on the forefoot during walking. But its advantages and disadvantages compared with plaster slab are still unknown.OBJECTIVE: To compare the clinical effects of over-the-toe plaster slab and off-loading forefoot shoes after hallux valgus correction.METHODS: Patients with hallux valgus undergoing distal Chevron osteotomy or Scarf osteotomy in the Huashan Hospital of Fudan University between May 2012 and October 2013 were retrospectively reviewed. Group A patients had a below-knee and over-the-toe plaster slab while Group B had an off-loading forefoot shoe applied after surgery.Radiological assessment was done at 6 weeks postoperatively. Immobilization was removed once bone union was indicated. Clinical scales and subjective satisfaction investigation were performed at final follow-up, and complications during follow-up were noted. All values between groups were analyzed statistically.RESULTS AND CONCLUSION: Totally 125 patients (157 feet) were completely followed up, including 83 patients (95 feet) in Group A and 42 patients (62 feet) in Group B. There was no significant difference in demographics, pre-and-post operative radiological assessments, clinical scale, union time or general satisfaction rates between two groups. However,Group B patients had less chance to suffer metatarsophalangeal joint or inter-phalangeal joint stiffness, restricted ankle motion and supra-ankle pains of operated side in comparison with Group A (P < 0.05), and were more willing to accept the same treatment if they could choose again (P < 0.05). Compared with the plaster slab, the application of off-loading shoes not only maintains correction level, but also reduces such complications as stiffness or restricted motion of the joint, limb pains and so on, which makes patients more likely to accept, and should be given priority to in the rehabilitation following hallux valgus correction.