Centurial deposition records of polychlorinated biphenyls and organochlorine pesticides in sediment cores from a plateau deep-water lake of China: Significance of anthropogenic impacts, transformation signals and ecological risks revealed by full congener analysis.

Lake Fuxian, the largest deep freshwater lake in China, has been suffering from increasing ecological and environmental issues along with the rapid urbanization and industrialization in the past 40 years. To better understand the historical pollution of persistent organic pollutants (POPs) in Lake Fuxian, comprehensive analyses of 209 polychlorinated biphenyl (PCB) congeners and 20 organochlorine pesticides (OCPs) were conducted in two intact sediment cores (Core V1 and Core V2). The total mass concentrations of PCBs ranged from 7.60 to 31.47 ng/g (dry weight basis) and 5.55 to 28.90 ng/g during the period of 1908-2019 in Core V1 and 1924-2019 in Core V2, respectively. PCBs exhibited a consecutive increasing trend from 1940s to 2019 in Core V1. The temporal trend of PCBs in Core V2 basically matched to the history of PCB usage and prohibition in China (increasing from 1940s to mid-1960s, a remarkable drop in mid-1970s, and then increasing until 2019). Moreover, low-chlorinated PCBs were dominant among PCB homologues. Mono-CBs, di-CBs, tri-CBs and tetra-CBs accounted for 86.71 %-98.57 % in sediment segments. The PCB sources included unintentional emission and atmospheric deposition, as well as biological transformation. The total mass concentrations of OCPs ranged from 0.74 to 3.82 ng/g in Core V1 and 0.35 to 2.23 ng/g in Core V2, respectively. Similar trend was observed in the two sediment cores with peaks in the early 1990s. The predominant OCPs were γ-hexachlorohexane (γ-HCHs), dieldrin and p,p'-DDD. The ecological risks posed by PCBs and p-p'-DDD in Lake Fuxian were relatively low. In contrast, dieldrin might pose a potential threat to exposed organisms and apparently adverse ecological effects were caused by γ-HCH. This study will provide important baseline information on historical POPs contamination of Lake Fuxian.

Risk factors for proximal junctional kyphosis in adult spinal deformity after correction surgery: A systematic review and meta-analysis.

OBJECTIVE: This study aimed to conduct a systematic review and meta-analysis to assess the risk factors for proximal junctional kyphosis after the correction surgery of adult spinal deformity. METHODS: Relevant studies were systematically retrieved from databases including Cochrane Library, PubMed, and Embase. Based on inclusion and exclusion criteria, literature screening, quality evaluation, and data extraction were conducted. Analysis was performed with Revman 5.3 software. RESULTS: Sixteen studies with 2388 patients, covering 905 cases with proximal junctional kyphosis and 1483 cases without proximal junctional kyphosis, were included in the study. The high-risk factors for the development of proximal junctional kyphosis were found to be high body mass index, osteoporosis, severe fatty infiltration of paravertebral muscles, small functional area of paravertebral muscles, lumbar lordosis over-correction, lack of ligament reinforcement device at the proximal vertebrae and upper instrumented vertebra at the thoracolumbar segment, and pelvic fixation. The results were statistically significant. CONCLUSION: Evidence from this study has revealed that the independent risk factors for proximal junctional kyphosis complications after correction surgery of adult spinal deformity are high body mass index, osteoporosis, severe degeneration of paravertebral muscles, lumbar lordosis overcorrection, fixed fusion to the pelvis, and lack of ligament reinforcement device at the proximal vertebrae and upper instrumented vertebra at the thoracolumbar segment. LEVEL OF EVIDENCE: Level IV, Therapeutic Study.

Long-Term Dechlorination of Polychlorinated Biphenyls (PCBs) in Taihu Lake Sediment Microcosms: Identification of New Pathways, PCB-Driven Shifts of Microbial Communities, and Insights into Dechlorination Potential.

Microbial reductive dechlorination of polychlorinated biphenyls (PCBs) is regarded as an alternative approach for in situ remediation and detoxification in the environment. To better understand the process of PCB dechlorination in freshwater lake sediment, a long-term (108 weeks) dechlorination study was performed in Taihu Lake sediment microcosms with nine parent PCB congeners (PCB5, 12, 64, 71, 105, 114, 149, 153, and 170). Within 108 weeks, the total PCBs declined by 32.8%, while parent PCBs declined by 84.8%. PCB dechlorinators preferred to attack meta- and para-chlorines, principally para-flanked meta and single-flanked para chlorines. A total of 58 dechlorination pathways were observed, and 20 of them were not in 8 processes, suggesting the broad spectrum of PCB dechlorination in the environment. Rare ortho dechlorination was confirmed to target the unflanked ortho chlorine, indicating a potential for complete dechlorination. PCBs drove the shifts of the microbial community structures, and putative dechlorinating bacteria were growth-linked to PCB dechlorination. The distinct jump of RDase genes ardA, rdh12, pcbA4, and pcbA5 was found to be consistent with the commencement of dechlorination. The maintained high level of putative dechlorinating phylum Chloroflexi (including Dehalococcoides and o-17/DF-1), genus Dehalococcoides, and four RDase genes at the end of incubation revealed the long-term dechlorination potential. This work provided insights into dechlorination potential for long-term remediation strategies at PCB-contaminated sites.

Biomechanical comparison of percutaneous posterior endoscopic cervical discectomy and anterior cervical decompression and fusion on the treatment of cervical spondylotic radiculopathy.

BACKGROUND: Cervical spondylotic radiculopathy is a common spinal disease. The traditional surgical treatment consists of anterior cervical decompression and fusion (ACDF), but it presents problems such as trauma and fusion complications. Percutaneous posterior endoscopic cervical discectomy (PPECD) is a new minimally invasive technology that has produced good clinical outcome, but further biomechanical comparisons are needed to guide the clinical work. The goal of this study was to compare the biomechanical characteristics of the two methods by finite element analysis. METHOD: On the basis of the computed tomography scanning data of five cases of cervical spondylosis after PPECD surgery, five cases after ACDF surgery, and five non-surgical patients, software (Mimics 15.0, HyperMesh 12.0, and Abaqus 6.13) was adopted to establish a C1-C7 segment 3D finite element model. We also applied 50 N vertical load on the C1 surface and 1.5 Nm torque, simulated the anteflexion, rear protraction, and left and right lateral flexion and rotation, and observed the stability, stress distribution, and Cobb angular change of the surgical section of the cervical vertebra under different working conditions. RESULT: The postoperative model under different working conditions demonstrated poorer stability than the non-surgical group, but the stability of the PPECD group was close to that of the non-surgical group. The stability of the ACDF group was the worst, especially when making lateral bending and posterior extension. The ACDF group also showed significant differences. The PPECD group showed uniform stress distribution, whereas the ACDF group was under large stress, which was primarily concentrated in the internal fixation system. In addition, the implant showed the potential for fracture. The Cobb angle of surgery section of the PPECD group was smaller than that of the ACDF group, and the stability of the section was good. CONCLUSION: From the perspective of finite element analysis, the cervical vertebrae after PPECD treatment showed good biomechanical performance and stability.

Effect of infusion speed of 7.5% hypertonic saline on brain edema in patients with craniocerebral injury: An experimental study.

This study firstly used a rat traumatic brain injury model to compare the therapeutic effects of different intravenous infusion speed of 7.5% hypertonic saline (HS). Then the authors applied different delivery rate of 7.5% HS to two groups of patients to figure out the optimal infusion rates. A total of 100 rats were randomly divided into control group, group A (7.5% HS 6 mL/h), group B (7.5% HS 3 mL/h), and group C (7.5% HS 2 mL/h). All rats were established for the brain injury model. A total of 30 patients were selected and randomly divided into group A (250 mL/h) and group B (125 mL/h), with 15 cases in each group. Urine amount was recorded per hour; furthermore, blood was extracted from the patients to measure the levels of AQP4, NKCC1, tumour necrosis factor-α (TNF-a), interleukin-1ß (IL-1ß), and interleukin-6 (IL-6). Compared with other groups, the expression levels of NKCC1 and AQP4 mRNA in group A was the lowest (P < 0.05). NKCC1 and AQP4 protein expression levels were the lowest in all the groups (P < 0.05). On the aspect of patients, group A displayed more significant difference compared with B group in terms of AQP4, NKCC1, TNF-a, IL-1ß, and IL-6 (P < 0.05). In the two groups, a significant difference was noted in the urine amount at 4 h after administration (P < 0.05). In our study, infusion of hypertonic saline (250 mL/h) at the optimal rate of 7.5% HS decreased the intracranial pressure, brain tissue edema, and inflammatory cytokine expression; moreover, it can promote brain tissue protection.