Background Metals and metalloids in fine particulate matter (PM_2.5) may cause damage to the respiratory and circulatory systems of the human body, and long-term exposure is prone to causing chronic poisoning, cancer, and other adverse effects. Objective To assess the distribution characteristics of metals and metalloids in outdoor PM_2.5 in a southern city of China, conduct source apportionment, and evaluate the associated health risks, thereby providing theoretical support for further pollution control measures. Methods PM_2.5 samples were collected in districts A, B, and C of a southern China city, and the concentrations of 17 metals and metalloids were detected by inductively coupled plasma-mass spectrometry (ICP-MS). Pollution sources were assessed through enrichment factor and principal components analysis, and the main pollution sources were quantified using absolute principal component scores-multivariate linear regression (APCS-MLR). Health risks were evaluated based on the Technical guide for environmental health risk assessment of chemical exposure (WS/T777—2021). Results The ambient air PM_2.5 concentrations in the city were higher in winter and spring, and lower in summer and autumn. The annual average concentrations of ambient PM_2.5 in districts A, B, and C were 36.7, 31.9, and 24.4 μg·m⁻³, respectively. The ambient PM_2.5 levels in districts B and C were below the second-grade limit set by the Ambient air quality standards (GB 3095—2012). The enrichment factors of cadmium (Cd), aluminum (Al), and antimony (Sb) were greater than 10, those of copper (Cu), lead (Pb), arsenic (As), nickel (Ni), mercury (Hg), and molybdenum (Mo) fell between 1 and 10, and those of manganese (Mn), vanadium (V), chromium (Cr), cobalt (Co), barium (Ba), beryllium (Be), and uranium (U) were below or equal to 1. The comprehensive evaluation of source analysis showed that the main pollution sources in districts A and C and the whole city were coal-burning. In district B, the main pollution source was also coal combustion, followed by industrial process sources and dust sources. The carcinogenic risks of As and Cr were between 1×10⁻⁶ and 1×10⁻⁴. However, the hazard quotients for 15 metals and metalloids in terms of non-carcinogenic risk were below 1. Conclusion Cr and As in the atmospheric PM_2.5 of the city present a certain risk of cancer and should be paid attention to. In addition, preventive control measures should be taken against relevant pollution sources such as industrial emission, dust, and coal burning.

ObjectiveTo understand the characteristics of PM_2.5 pollution in the air of Pearl River Delta city in Guangdong Province under the COVID-19 epidemic and the health risks of inhaling elements in PM_2.5. MethodsIn 2022， 10 PM_2.5 monitoring points were set up in 10 districts in Guangzhou， Shenzhen， Foshan and Zhuhai， and air samples were collected for 7 consecutive days every month to analyze the concentration of PM_2.5 and the 12 elements in PM_2.5. The classic "four-step" method was used to evaluate the carcinogenic risk and chronic non-carcinogenic risk of the elements in air PM_2.5 on health. The age-sensitive characteristics of metal elements were combined in the carcinogenic risk assessment， and age-sensitive factors were introduced to analyze the impact of air pollution on population health. ResultsA total of818 samples were collected. and the average annual PM_2.5 concentration in the four cities of the Pearl River Delta was 30.17 （1.00-166.00， s=21.06） μg·m^-3， which was lower than the concentration limit of the secondary standard of the Ambient Air Quality Standard （GB 3095-2012）. The difference of PM_2.5 concentration in the four cities was statistically significant. The PM_2.5 concentrations in Zhuhai and Shenzhen， which were located near the sea， were lower than those in Guangzhou and Foshan. The monthly mean concentration of PM_2.5 in the four cities was the lowest at 13.70 （4.00-34.00， s=5.93） μg·m^-3 in July and the highest at 57.73 （14.00-146.00， s=27.96） μg·m^-3 in January， showing a low concentration from May to October and a high concentration from November to April of the following year. The average daily PM_2.5 concentration exceeded the secondary standard for 29 days， mainly distributed in January and November. The average annual mass concentration of elements in PM_2.5 in the four cities was Al>Mn>Pb>As>Ni>Cr>Se>Sb>Cd>Tl>Be>Hg. AS and Mn have chronic non-carcinogenic risk in population， while Cr， AS， Cd， Be and Ni have carcinogenic risk in population. ConclusionThe PM_2.5 pollution levels of the four cities in the Pearl River Delta are low and variable. Coastal cities are lower than non-coastal cities， which shows the characteristics of first decreasing and then increasing throughout the year. The order of mass concentration of metal elements of PM_2.5 in four cities is basically the same except Be and Ni. As and Mn in PM_2.5 show a certain degree of chronic non-carcinogenic risk， and As， Cr， Cd， Ni and Be have a certain degree of carcinogenic risk. The four cities need to take effective intervention measures to continue to strengthen the pollution control and health protection of Cr， As， Cd and Mn in the air， and control the health burden caused by air pollution.

Replantation of traumatic amputation in children has its own characteristics. This consensus primarily focuses on the issues related to the treatment of traumatically amputated limb injuries in children. Organised along a timeline, the consensus summarises domestic and international clinical experiences in emergency care and injury assessment of traumatic limb amputation limbs, indications and contraindications for replantation surgery, principles and procedures of replantation surgery, postoperative medication and management, as well as rehabilitation in children. The aim of this consensus is to propose standardise the treatment protocols for limb replantation for children therefore to serve as a reference for clinical practitioners in medical practices, and further improve the treatment and care for the traumatic limb amputations in children.

Objective:To explore the surgical procedure and effect of reconstruction of soft tissue defects in the distal segment of dorsal finger with a perforator(joint branch) flap of proper palmar digital artery combined with a dorsal metacarpal artery flap.Methods:From January 2019 to June 2022, 9 patients with soft tissue defects in distal dorsal finger, mostly with avulsion at the extensor tendon insertion point, were treated in Department of Hand and Foot Microsurgery, the Affiliated Hospital of Qingdao University. The defect areas were 1.0 cm×1.0 cm-2.5 cm×2.0 cm. Steel wires were used to reconstruct the extensor tendon insertion point. The defects were reconstructed by a perforator(joint) flap of proximal phalanx artery and a dorsal metacarpal artery flap was used to repair the donor site for proximal flap. Postoperative follow-up and evaluation included flap survival, flap appearance, scars and function of interphalangeal and metacarpophalangeal joints, through outpatient clinical, WeChat and so on.Results:The flap of digital artery perforator (joint branch) and the fasciocutaneous flap of dorsal metacarpal artery all survived. One flap of the digital artery perforator(joint branch) appeared purple and tension blisters after surgery. The stitches of the pedicle of the flap were partially dismantled at 36-48 hours after surgery. The flap was then turned to ruddy in colour 7 days after surgery. The wounds of the distal finger joint and nail bed healed well without redness and infection. The postoperative follow-up lasted for 5 to 12 months, 9 months in average. The appearance, colour and texture of the skin at distal finger were similar to those at the dorsal proximal finger and dorsal palm. Sensation recovered well, all flaps exceeding S 3. The two-point resolution (TPD) was 8-10 mm, with an average of 9.5 mm. According to the Evaluation Standard of Upper Limb Partial Functional of Hand Surgery of Chinese Medical Association, 5 cases were in excellent and 4 in good. Conclusion:The perforator(joint branch) flap of proper palmar digital artery combined with a dorsal metacarpal artery flap is simple and safe treatment. It has a fast functional recovery with an aesthetic appearance in reconstruction of the soft tissue defect in distal segment of dorsal finger.

Objective:To investigate the clinical effect of bilateral anteriolateral thigh perforator flaps (ALTPF) pedicled with descending branch of lateral circumflex femoral artery in series on reconstruction of large soft tissue defects in lower limbs.Methods:A total of 9 patients with large soft tissue defects in lower limbs were selected in the study. The patients were 6 males and 3 females aged between 18 and 57 years old. They were treated in the Department of Hand and Foot Microsurgery, the Affiliated Hospital of Qingdao University from June 2018 to January 2023. Causes of injury: 4 of traffic accident, 2 of crushing, 2 of falling from height and 1 of explosion. Five patients had combined defects in dorsal feet and 4 with tibia fractures and anterior-and-posterior-tibial soft tissue defects. All affected limbs had tissue necroses and infections in various degrees. Deep tissue defects such as tendons, nerves, bones and joints or orthopaedic implants were exposed. The areas of soft tissue defects were 30 cm×14 cm-42 cm×14 cm. All the defects were reconstructed by the bilateral ALTPF pedicled with descending branch of lateral circumflex femoral artery in series. The size of proximal flaps was 25 cm×8 cm-33 cm×13 cm and 20 cm×7 cm-29 cm×13 cm for the distal flaps. Scheduled postoperative follow-ups were conducted to observe the survival of the transferred flaps and functional recovery of calfs and feet. Sensory recovery was assessed against British Medical Research Council (BMRC) criteria. Puno scoring was used to assess the functional recovery and the effectiveness of treatment.Results:All flaps survived and the donor sites healed well. One patient developed vascular compromise within 24 hours after surgery, but it was rectified after timely surgical exploration, however it left with a small area of necrosis at distal end of the flap. The necrosis and wound healed after skin grafting in stage-two surgery. Postoperative follow-up lasted for 8.3 months in average. Two patients underwent flap thinning in stage-two surgery due to bloating appearance, 2 patients had slightly bloated flaps at the calfs, and the rest of 5 patients had satisfactory flap appearance. Two patients received nerve reconstruction by anastomosis of the lateral femoral cutaneous nerves. At the final follow-up, the sensory recovery in 9 patients achieved S 2-S 3+ according to BMRC. The average Puno score achieved 88.36 point±5.36 point, of which 4 patients in excellent, 3 in good and 2 in fair. Conclusion:The use of bilateral ALTPF pedicled with descending branch of lateral circumflex femoral artery in series to reconstruct a large soft tissue defect in lower extremity has a good clinical value, and it has become one of the effective methods.

Objective:To explore the clinical application of free chimeric medial femoral condyle osteofascial free flap (CMFCOF) in the treatment of traumatic composite bone and soft tissue defect of hand and foot.Methods:Between January, 2015 and March, 2020, 8 patients with traumatic composite bone and soft tissue defect in hand and foot were treated with CMFCOF. Of the 8 patients, there were 6 males and 2 females, with an average age of 41 (range, 24 to 56) years. The causes of injury included 3 of traffic accident, 3 of machine crush and 2 of crush. Two cases had proximal phalanx defect, 3 with metacarpal bone and 3 with metatarsal bone. The time between injury to the flap repair were 2 to 120 (mean, 84) days. The size of bone defect ranged from 2.0 cm×1.2 cm×1.2 cm to 4.4 cm× 3.0 cm×2.3 cm. The soft tissue defect ranged from 2.0 cm×1.4 cm to 5.6 cm×4.5 cm. All bone defects were on the diaphysis, without involvement of joints. Two cases had tendon defect. According to the defect of bone and soft tissue, the CMFCOF was prepared and skin graft was performed on the surface of its fascial flap.Results:The average time of flap harvesting was 53(52-96) minutes. All donor sites were directly closed. All flaps and skin grafts achieved stage I survival. All patients entered 9-16 months of follow-up, with an average of 14.5 months. The average healing time of bone was 7.5 (range, 6-10) weeks. At the last follow-up review, all flaps were not thinned. The function of donor site was restored well, without weight bearing disorder and paraesthesia in the anterior patella area. According to the trial standard of Digit Function Evaluation of the Hand Surgery Society of Chinese Medical Association, 3 patients were rated as excellent, 1 was good and 1 was fair. According to the Maryland foot evaluation criteria, 3 patients were rated as excellent for recovered with normal weight-bearing walking.Conclusion:CMFCOF can achieve satisfactory results in repairing composite bone and soft tissue defect of hand or foot. The flap has the advantages in simple operation, high quality of bone and concealed donor site.

The article aims to explore the optimal concentration of arsenic trioxide (As O ) on HepG2 of liver cancer cells, and the effect of As O on the migration, invasion and apoptosis of HepG2 cells. In this study, the activity of HepG2 cells treated with 0, 1, 2, 4, 8, 16, 32 μmol/L As O was tested by CCK-8 method, the semi-inhibitory concentration (IC50) was calculated, and the morphological changes of HepG2 cells were observed after the action of As O at IC50 concentration for 12, 24, 48 h. The effect of As O on cell migration and invasion ability was verified by wound healing experiment and Transwell invasion experiment. Western blot and qRT-PCR were used to detect the effects of As O on the gene and protein expression levels related to cell migration, invasion and apoptosis. The results showed that, compared with the control group, the activity of HepG2 cells decreased with the increase of the concentration of As O treatment, showing a dose-dependent effect, and its IC50 was 7.3 μmol/L. After 24 hours' treatment with 8 μmol/L As O , HepG2 cells underwent significant apoptosis, and its migration and invasion abilities were significantly reduced. In addition, the protein expression levels of RhoA, Cdc42, Rac1 and matrix metalloproteinase-9 (MMP-9) were down-regulated, the protein and mRNA expression levels of anti-apoptotic gene Bcl-2 were significantly down-regulated, and the protein and mRNA expression levels of pro-apoptotic genes Bax and Caspase-3 were significantly up-regulated. The above results indicate that certain concentration of As O can inhibit the migration and invasion of hepatocellular carcinoma cells and promote the apoptosis of hepatocellular carcinoma cells.

This study aims to investigate the effect of substances secreted or metabolized by vascular endothelial cells on epithelial-mesenchymal transition (EMT) of hepatocellular carcinoma cells under indirect co-culture condition. Human hepatocellular carcinoma cell line QGY-7703 was cultured , and then was co-cultured with conditioned medium of human umbilical vein endothelial cells (HUVEC). The morphological changes of QGY-7703 cells were observed by inverted phase contrast microscopy. The migration ability of QGY-7703 cells was analyzed by scratch-wound assays. The effect of conditioned medium on the expression and distribution of EMT related proteins was detected by Western blot and immunofluorescence assays, respectively. The results showed that the QGY-7703 cells gradually changed from polygonal to spindle shape, the migration ability promoted significantly, and both the expression and distribution of EMT related marker changed in a time-dependent manner after co-culturing. The results confirm that vascular endothelial cells can induce EMT in hepatocellular carcinoma cells under indirect co-culture condition.

As drug carriers, magnetic nanoparticles can specifically bind to tumors and have the potential for targeted therapy. It is of great significance to explore non-invasive imaging methods that can detect the distribution of magnetic nanoparticles. Based on the mechanism that magnetic nanoparticles can generate ultrasonic waves through the pulsed magnetic field excitation, the sound pressure wave equation containing the concentration information of magnetic nanoparticles was derived. Using the finite element method and the analytical solution, the consistent transient pulsed magnetic field was obtained. A three-dimensional simulation model was constructed for the coupling calculation of electromagnetic field and sound field. The simulation results verified that the sound pressure waveform at the detection point reflected the position of magnetic nanoparticles in biological tissue. Using the sound pressure data detected by the ultrasonic transducer, the B-scan imaging of the magnetic nanoparticles was achieved. The maximum error of the target area position was 1.56%, and the magnetic nanoparticles regions with different concentrations were distinguished by comparing the amplitude of the boundary signals in the image. Studies in this paper indicate that B-scan imaging can quickly and accurately obtain the dimensional and positional information of the target region and is expected to be used for the detection of magnetic nanoparticles in targeted therapy.
Acoustics ; Computer Simulation ; Magnetics ; Magnetite Nanoparticles ; Tomography

Cell autophagy plays a key role in maintaining intracellular nutritional homeostasis during starvation through elimination of aberrant or obsolete cellular structures. The cellular cytoskeleton has a crucial role in multiple processes involving membrane rearrangements and vesicle-mediated events. Autophagy is mediated by both microtubules and actin networks: microtubules promote the synthesis of autophagosome and are related to the movement of autophagosome; actin networks have been implicated in structurally supporting the expanding of phagophore, moving autophagosomes and enabling their efficient fusion with the lysosome; non-muscle myosinⅡoperates in the early stages of autophagy during the initiation and expansion of the phagophore, whereas myosinⅥ and myosin 1C are involved in the late stages of autophagosome maturation and fusion with the lysosome, respectively. This review summarizes the multiple regulation of cytoskeleton on autophagy and focuses on the regulation of autophagy by actin and myosin, providing a new approach for the study of pathogenesis and innovative therapies of autophagy related diseases.