Biotoxicity of Halide Perovskites in Mice.

Halide perovskites are crystalline semiconductors with exceptional optoelectronic properties, rapidly developing toward large-scale applications. Lead (II) (Pb2+ ) is the core element used to prepare halide perovskites. Pb2+ can displace key 2+ elements, including calcium, zinc and iron, that regulate vital physiological functions. Sn2+ can replace Pb2+ within the perovskite structure and, if accidentally dispersed in the environment, it readily oxidizes to Sn4+ , which is compatible with physiological functions and thus potentially safe. The 3+ salt bismuth (III) (Bi3+ ) is also potentially safe for the same reason and useful to prepare double perovskites. Here, this work studies the biotoxicity of Pb, Sn, and Bi perovskites in mice for the first time. This work analyses histopathology and growth of mice directly exposed to perovskites and investigate the development of their offspring generation. This study provides the screening of organs and key physiological functions targeted by perovskite exposure to design specific studies in mammalians.

An Investigation of Toxic Metal Levels (Pb, Cd, Cr, As, Hg) in Dried Porphyra and Laminaria Collected from Coastal Cities, China.

This investigation was aimed at determining the concentration levels of five toxic heavy metals (lead, cadmium, chromium, arsenic, and mercury) in dried Porphyra and Laminaria samples from coastal city of China. Inductively coupled plasma-mass spectrometry (ICP-MS) was used for determination of lead, cadmium and total arsenic. Atomic fluorescence spectrometry was used for mercury, and liquid chromatography coupled with ICP-MS was used for arsenic speciation. The mean concentrations of lead, cadmium, chromium, total arsenic, and mercury were 0.96 ± 0.03 mg/kg, 2.62 ± 0.07 mg/kg, 1.64 ± 0.08 mg/kg, 36.67 ± 0.53 mg/kg, and 7.56 ± 0.42 µg/kg for Porphyra samples and 0.61 ± 0.03 mg/kg, 0.48 ± 0.02 mg/kg, 3.78 ± 0.56 mg/kg, 43.85 ± 1.42 mg/kg, and 46.61 ± 2.02 µg/kg for Laminaria samples. The results were comparable with previous similar research. The potential health risk assessment was conducted by comparing the calculated weekly intakes of toxic metals from Porphyra and Laminaria with provisional tolerable weekly intake. Consumption of these seaweeds does not seem to pose a risk for the consumers' health regarding their content of heavy metals. However, the potential health risk of cadmium should not be overlooked for consumers with high intake of Porphyra.

[Anatomical study on the feasibility of a new self-guided pedicle tap].

OBJECTIVE: To evaluate the accuracy and safety of pedicle screw placement using a new self-guided pedicle tap. METHODS: According to the anatomical characteristics of the pedicle, a new self-guided pedicle tap was developed. Six adult spinal specimens including 4 males and 2 females were selected and tapped thread on the right and left sides of each pair of pedicles from the same segment T1 to L5 with traditional taps (control group) and new self-guided pedicle taps (experimental group), respectively. And the pedicle screws were placed. The screwing time was recorded and compared between two groups. CT scanning was completed to observe the accuracy and safety of the screw placement according to the Heary classification of imaging results. RESULTS: The screwing time of thoracic and lumbar vertebrae in the experimental group were (5.87±1.25) min and(5.45±1.67) min, respectively. While those in the control group were (6.12±1.69) min and (6.22±2.13) min, respectively. Then there was no significant difference in screwing time of thoracic and lumbar vertebrae between two groups (P>0.05). The Heary grade of the pedicle screw showed that Heary gradeⅠand Heary gradeⅠ+Ⅱwere respectively 86 (84.31%) and 96 (94.12%) in the experimental group, 72 (71.29%) and 84 (83.17%) in control group, and the difference between two groups was statistically significant (P<0.05). CONCLUSION: The new self-guided pedicle tap can accurately and safely insert the thoracolumbar pedicle screw, with low cost, easy operation, and good clinical application value.

[Application of absorbable hemostatic fluid gelatin in anterior cervical subtotal vertebral resection and fusion].

OBJECTIVE: To explore the hemostatic effect of absorbable hemostatic fluid gelatin in single anterior cervical subtotal corpectomy and decompression fusion (ACCF) . METHODS: From August 2014 to February 2018, 44 patients with single anterior cervical corpectomy decompression and fusion were selected and divided into two groups：22 cases in experimental group including 10 males and 12 females with an average age of (55.6±9.7) years old, were treated by hemostasis with absorbable hemostasis fluid gelatin; 22 cases in control group including 11 males and 11 females with an average age of (54.4± 11.1) years old were treated by hemostasis with traditional hemostasis method. The operation time, decompression time, intraoperative hemorrhage, postoperative negative pressure drainage, postoperative neurological improvement rate (JOA%) , postoperative bone fusion time, postoperative titanium mesh subsidence rate, postoperative hematoma and other postoperative complications were compared between the two groups. RESULTS: The operative time of the experimental group (83.1±19.2) min was significantly shorter than that of the control group (89.5±17.0) min (P<0.05) ; the decompression time of the spinal canal in the two groups was (52.4±13.7) , (56.1±14.6) min, with a statistically significant difference (P=0.001) ; the amount of bleeding in the two groups was (49.9±12.4) , (90.6±36.7) ml, with a statistically significant difference (P<0.05) ; the total amount of drainage in the negative pressure drainage ball after operation in the two groups was (42.5±18.3) , (60.0±22.8) ml, the difference was statistically significant (P<0.05) . There was no statistically significant difference in the improvement rate of nerve function between the two groups at 1 week after operation, and the improvement rate of nerve function in the experimental group was better than that in the control group at 3 and 6 months after operation. In the two groups, bone fusion was obtained 6 months after operation, no obvious titanium mesh subsidence was found in 3 months after operation, no acute hematoma, CSF leakage and other postoperative complications were found. CONCLUSION: Absorbable hemostatic fluid gelatin has a significant hemostatic effect in ACCF operation, can maintain a good operation field, can reduce the decompression time of spinal canal, reduce the amount of bleeding during operation and the amount of bleeding after operation. It is a more effective and safe hemostatic material than the traditional hemostatic method.

[Therapeutic effect and imaging study of directional bone cement guide for the treatment of thoracolumbar vertebral compression fractures].

OBJECTIVE: To evaluate the therapeutic effects and bone cement distribution of unilateral percutaneous kyphoplasty (PKP) with oriented bone cement injector for thoracolumbar osteoporotic vertebral compression fractures (OVCFs). METHODS: The clinical data of 211 patients (211 vertebrae) with thoracolumbar osteoporotic compression fractures underwent PKP between July 2016 to July 2018 were retrospectively analyzed. All punctures were performed unilaterally:102 patients in observation group used oriented bone cement injector including 30 males and 72 females with an average age of (68.4±8.9)years old; 109 patients in regular group used traditional bone cement injector including 32 males and 77 females with an average age of (70.4±9.2) years old. The two groups were compared in terms of duration of operation, cement volume, visual analogue scale(VAS), Oswestry Disability Index(ODI), distribution of bone cement, bone cement leakage and Cobb angle modified rate. RESULTS: There were no significant difference in gender, age and fracture vertebra between the two groups(P>0.05). No significant difference was found between two groups in duration of operation, cement volume, VAS, ODI and Cobb angle(P>0.05). In observation group, 10 cases occurred cement leakages, with leakage rate of 9.80%; and in regular group, 11 cases occurred cement leakage, with leakage rate of 10.09%. There was no significant difference in the cement leakage rate between two groups(P>0.05). In observation group, proportion rate of I-IV degree in cement distribution was 60.78%, 19.61%, 9.80%, 9.80%, respectively; while 39.45%, 22.93%, 22.93%, 14.68% in regular group. The I degree of cement cross-filling rate was better in observation group than in regular group(P<0.05). There was no significant difference between two groups in II degree distribution rate of bone cement(P>0.05). From T10 to L5, I degree bone cement distribution rate of both groups showed decline trend. The I degree cement cross-filling rate in L1-L5 was 50% in observation group and 30.23% in regular group(P<0.05). CONCLUSIONS: Oriented bone cement injector can control the direction of bone cement dispersion and achieve effective distribution of bilateral bone cement using unilateral puncture and satisfactory surgical results. It is feasible and effective for unilateral PKP treatment of OVCFs.