Study on the Effect of Additives on the Performance of Cement-Based Composite Anti-Corrosion Coatings for Steel Bars in Prefabricated Construction.

The influence of polymer emulsion, pigment filler, and dispersant on the corrosion resistance of polymer cement-based composite anti-corrosion coatings were investigated in this study. Adhesion loss rate tests and electrochemical tests were conducted on samples. The research results show that optimal corrosion resistance can be achieved with a 45 wt% dosage of emulsion, a 6 wt% dosage of pigment filler, and a 0.30 wt% dosage of dispersant. The bonding properties of bare steel bars, epoxy-coated steel bars, and polymer cement-based composite anti-corrosion coated steel bars with grout were compared. The results show that the polymer cement-based composite anti-corrosion coating can enhance the bonding properties of the samples. Furthermore, the microscopic analysis was conducted on the samples. The results demonstrate that the appropriate addition of emulsion can fill internal pores of the coating, tightly bonding hydration products with unhydrated cement particles. Moreover, incorporating a suitable dosage of functional additives enhances the stability of the coating system and leads to a denser microstructure.

Comparative Study of Anti-Corrosion Properties of Different Types of Press-Hardened Steels.

Hot stamping (or press hardening) is a new technology that is widely used in the production of advanced high-strength steel parts for automotive applications. Electrochemical measurements, including potentiodynamic polarization and electrochemical impedance spectroscopy (EIS), and accelerated corrosion tests (the neutral salt spray test and periodic immersion test) were conducted on press-hardened samples produced from uncoated (cold-rolled and cold strip production (CSP) hot-rolled) and Al-Si-coated press-hardened steels to elucidate their distinct anti-corrosion mechanisms. The cross-sectional micromorphology and element distribution of three types of press-hardened steels after a neutral salt spray test were observed using scanning electron microscopy (SEM) and energy-dispersive X-ray analysis (EDAX). The corrosion resistance of Al-Si-coated press-hardened steel was found to be significantly diminished following the hot stamping process due to the presence of microcracks and elevated iron content in the coating subsequent to austenitizing heat treatment. On the other hand, the corrosion resistance of uncoated press-hardened sheets produced from cold-rolled and CSP hot-rolled press-hardened steel was found to be proximal due to their nearly identical composition and microstructure (fully martensite) after the hot stamping process. Considering the high efficiency and energy-saving properties of hot-rolled press-hardened steel, it holds the potential to replace cold-rolled and even aluminum-silicon-coated press-hardened steel in automobile manufacturing.

Predictive Value of Preoperative Short Form-36 Survey Scale for Postoperative Axial Neck Pain in Patients With Degenerative Cervical Myelopathy.

STUDY DESIGN: Prospective observational study. OBJECTIVE: To evaluate the predictive value of the preoperative Short Form-36 survey (SF-36) scale for postoperative axial neck pain (ANP) in patients with degenerative cervical myelopathy (DCM) who underwent anterior cervical decompression and fusion (ACDF) surgery. METHODS: This study enrolled patients with DCM who underwent ACDF surgery at author's Hospital between May 2010 and June 2016. RESULTS: Out of 126 eligible patients, 122 completed the 3-month follow-up and 117 completed the 1-year follow-up. The results showed that the preoperative social functioning (SF) subscale score of the SF-36 scale was significantly lower in patients with moderate-to-severe postoperative ANP than in those with no or mild postoperative ANP at both follow-up timepoints (P < .05). ACDF at C4-5 level resulted in a higher ANP rate than ACDF at C5-6 or C6-7 level, both at 3-month (P = .019) and 1-year (P = .004) follow-up. Multivariate logistic regression analysis confirmed that the preoperative social functioning subscale score was an independent risk factor for moderate-to-severe postoperative ANP at 3 months and 1 year after surgery, and preoperative NRS was an independent risk factor at 1-year follow-up. No other demographic, clinical, or radiographic factors were found to be associated with postoperative ANP severity (P < .05). CONCLUSIONS: Preoperative social functioning subscale score of SF-36 scale might be a favorable predictive tool for postoperative ANP in DCM patients who underwent ACDF surgery.

Hip subluxation in children with spinal cord injury: Incidence and influencing factors.

OBJECTIVE: Hip subluxation is a common complication in children with spinal cord injury. This study aimed to investigate the incidence and influencing factors of hip subluxation and discuss prevention strategies. METHODS: Medical records of children with spinal cord injury were reviewed. The inclusion criteria were as follows: (1) the patient was younger than 18 years old when injured; (2) absence of traumatic or congenital pathological changes of the hip at the time of injury. The migration percentage and acetabular index were selected to evaluate hip stability and acetabulum development. Influencing factors of sex, age, injury duration, severity, level, and spasticity were analyzed. RESULTS: A total of 146 children were enrolled. Twenty-eight children presented with hip subluxation and were significantly younger at the time of injury than those with normal hips (P = 0.002). The incidence of hip subluxation increased with the prolonged injury duration. Injury before age 6, complete injury, and flaccid lower extremities were significant influencing factors (P = 0.003, 0.004, and 0.015, respectively). The risk of hip subluxation decreased by 18% for every year older in injury age (P = 0.031) and decreased by 85% in children with spasticity (P = 0.018) than those without. However, the risk of hip subluxation in children with injury duration longer than 1 year was 7.1 times higher than those with shorter injury duration (P < 0.001). CONCLUSIONS: The incidence of hip subluxation in children with spinal cord injury increased with the injury duration. Younger children had immature hip development. Due to complete injury and flaccid muscle, lack of protection around the hip may lead to subluxation. Follow-up and prevention of hip subluxation need the joint effort of medical staff and families.

Novel Physical Examination Tests for the Diagnosis of Chronic Sacroiliac Joint Dysfunction and Differentiate It From Lumbar Disc Herniation.

BACKGROUND: Traditional sacroiliac joint (SIJ) provocation tests have been used to diagnose SIJ pain. However, this can simply be changed to chronic SIJ dysfunction (cSIJD) manifests as mechanical changes in the pelvis and lower extremities in addition to pain. A novel composite of physical examinations based on the iliac pronation, pubic tubercle tenderness, and plantar fascia tenderness tests (IPP triple tests) was designed for the diagnosis of cSIJD. OBJECTIVES: To evaluate IPP triple tests in the diagnosis of cSIJD and differential diagnosis from lumbar disc herniation (LDH) in comparison with traditional provocation tests. STUDY DESIGN: Prospective single-blind controlled study. SETTING: This study was conducted at the Department of Spine and Spinal Cord Surgery of China Rehabilitation Research Center in Beijing, China. METHODS: One hundred and sixty-six patients were assigned into the cSIJD group, LDH group, or healthy control group. The cSIJD diagnosis was confirmed by SIJ injection. The diagnosis of LDH was confirmed according to the 2014 North American Spine Association diagnosis and treatment guidelines for LDH. All patients were examined with IPP triple tests and traditional provocation tests. The sensitivity, specificity, positive and negative likelihood ratios, and areas under the curve (AUCs) were used to evaluate the diagnostic accuracy of the composites or single of the IPP triple tests, and traditional provocation tests. The Delong's test was used for the comparison among AUCs. The kappa analysis was used for the IPP triple tests and traditional provocation tests compared with the reference standard (REF). The independent t test and chi-square test were used to analyze the influence factors (i.e., age, gender), and group on diagnostic accuracy. RESULTS: There was no statistical difference in gender (chi-squared = 0.282, P = 0.596) and age (F = 0.096, P = 0.757) between the 3 groups. The AUC of the iliac pronation test was 0.903 when it was used alone; the AUC of the novel composites of the IPP triple tests was 0.868 (95% confidence interval [CI] = 0.802-0.919); and the diagnostic accuracy of the traditional provocation test was relatively low (AUC = 0.597, 95% CI = 0.512-0.678). The diagnostic accuracy of the IPP triple tests was higher than that of the traditional provocation test, P < 0.05. Kappa consistency comparison showed that the kappa value between the IPP triple tests and the REF was 0.229, the kappa between the traditional provocation test and the REF was 0.052. The age of the patients with inaccurate diagnosis was higher than that of the patients with accurate diagnosis in both methods (traditional tests, P = 0.599; IPP:P = 0.553). Different types of diseases (groups) affect the accuracy of diagnosis, the proportion of inaccuracy of traditional provocation tests was higher than that of the IPP triple tests (77.8% vs 23.6%) in cSIJD, while the 2 methods have high differential diagnostic accuracy in LDH (96.77%) and control groups (97.56%). LIMITATIONS: Small size of LDH patients and differences in physical tests among examiners. CONCLUSIONS: The novel composites of IPP triple tests have higher accuracy than the traditional provocation tests in diagnosing cSIJD and both have good accuracy in differentiating cSIJD from LDH. IPP triple tests may be an alternative physical examination for clinical screening of cSIJD.

Predicting deep surgical site infection in patients receiving open posterior instrumented thoracolumbar surgery: A-DOUBLE-SSI risk score - a large retrospective multicenter cohort study in China.

BACKGROUND: To develop a practical prediction model to predict the risk of deep surgical site infection (SSI) in patients receiving open posterior instrumented thoracolumbar surgery. METHODS: Data of 3419 patients in four hospitals from 1 January 2012 to 30 December 2021 were evaluated. The authors used clinical knowledge-driven, data-driven, and decision tree model to identify predictive variables of deep SSI. Forty-three candidate variables were collected, including 5 demographics, 29 preoperative, 5 intraoperative, and 4 postoperative variables. According to model performance and clinical practicability, the best model was chosen to develop a risk score. Internal validation was performed by using bootstrapping methods. RESULTS: After open posterior instrumented thoracolumbar surgery, 158 patients (4.6%) developed deep SSI. The clinical knowledge-driven model yielded 12 predictors of deep SSI, while the data-driven and decision tree model produced 11 and 6 predictors, respectively. A knowledge-driven model, which had the best C-statistics [0.81 (95% CI: 0.78-0.85)] and superior calibration, was chosen due to its favorable model performance and clinical practicality. Moreover, 12 variables were identified in the clinical knowledge-driven model, including age, BMI, diabetes, steroid use, albumin, duration of operation, blood loss, instrumented segments, powdered vancomycin administration, duration of drainage, postoperative cerebrospinal fluid leakage, and early postoperative activities. In bootstrap internal validation, the knowledge-driven model still showed optimal C-statistics (0.79, 95% CI: 0.75-0.83) and calibration. Based on these identified predictors, a risk score for deep SSI incidence was created: the A-DOUBLE-SSI (Age, D [Diabetes, Drainage], O [duration of Operation, vancOmycin], albUmin, B [BMI, Blood loss], cerebrospinal fluid Leakage, Early activities, Steroid use, and Segmental Instrumentation) risk score. Based on the A-DOUBLE-SSI score system, the incidence of deep SSI increased in a graded fashion from 1.06% (A-DOUBLE-SSIs score ≤8) to 40.6% (A-DOUBLE-SSIs score>15). CONCLUSIONS: The authors developed a novel and practical model, the A-DOUBLE-SSIs risk score, that integrated easily accessible demographics, preoperative, intraoperative, and postoperative variables and could be used to predict individual risk of deep SSI in patients receiving open posterior instrumented thoracolumbar surgery.

Prognosis of traumatic spinal cord injury in children: Follow-up of 86 patients.

PURPOSE: The long-term situation of children with spinal cord injury (SCI) was investigated, and suggestions for helping them better return to the society were provided. METHODS: SCI patients less than 18 years old hospitalized in Beijing Boai Hospital from January 2011 to December 2020 were retrospectively analyzed. Information including motor function, complications, characteristic changes, self-care abilities, school attendance and social participation were collected by telephone interview and electronic questionnaire. All the answers were statistically analyzed. RESULTS: A total of 86 cases were enrolled, 77 girls and 9 boys, with a median injury age of 6 years and 2 months. The follow-up time was 3-130 months. The main cause of trauma in these children was sport injury (66.3%), the thoracic spinal cord was involved the most (91.9%), and complete SCIs accounted for the majority (76.7%). In terms of complications, children with complete SCIs were more likely to have urinary incontinence, constipation and characteristic changes (p < 0.05); whereas the incomplete SCIs often have spasticity (p < 0.05). As to the daily living abilities, children with incomplete lumbar SCIs were more capable to accomplish personal hygiene, transfer, and bathing independently than those with complete injuries, or cervical/thoracic SCIs, respectively (p < 0.05). Moreover, children older than 9 years care more able to dress and transfer independently than the youngers (p < 0.05). Wheelchair users accounted for 84.9% and more than half of them were able to propel wheelchair independently, and those who move passively in wheelchairs were mostly introverted kids (p < 0.05). Almost all (93.8%) children with incomplete injuries were able to walk independently. Most (79.1%) children continued to attending school, and 41.9% participated in interest classes. Unfortunately, 67.4% of the children spent less time playing with their peers than before the injury. CONCLUSION: SCIs impair physical structures and function of children, affect their independence in daily living, and restrict school attendance and social interaction. Comprehensive rehabilitation after injury is a systematic work. Medical staff and caregivers should not only pay attention to neurological function, but also help them improve self-care abilities. It is also important to balance rehabilitation training and school work and social participation.

Clinical characteristics of pediatric traumatic spinal cord injury in China: A single center retrospective study.

OBJECTIVE: To investigate the clinical characteristics of children with traumatic spinal cord injury (SCI) admitted to a research rehabilitation center between 2011 and 2020, with a view to generate crucial data for understanding and prevention of pediatric traumatic SCI. DESIGN: Retrospective cohort study. SETTING: The National Rehabilitation Research Center of China, Beijing, China. PARTICIPANTS: Medical records and imaging data of children with traumatic SCI admitted to the rehabilitation research center from 2011 to 2020. INTERVENTIONS: Not applicable. OUTCOME MEASURES: Data on age, sex, cause of injury, neurological level of injury, impairment scale of SCI and details of spine fracture or dislocation were all collected and analyzed. RESULTS: A total of 351 patients were included in the study, including 133 males (37.9%) and 218 females (62.1%). There were 231 cases (65.8%) without spine fracture or dislocation. SCI without fracture or dislocation (SCIWORA) was the most common in children between the age of 5 and 14 years (77.9%), and injuries caused by sports were the most common in girls (90.8%). Among sports injuries, those due to a special dance movement called "Xia-Yao" in Chinese, which involves hyperextension of the trunk, constituted the majority, with the neurological level of injuries located predominantly in the middle (34.6%) and lower (44.2%) thoracic levels. CONCLUSION: Girls between the ages of 5 and 14 years constituted the majority of SCIWORA injuries at the thoracic levels, which were caused mainly by "Xia-Yao". Overall, careful attention should be paid to prevent this kind of injury in children.

Efficacy of lumbar kinetic chain training for staged rehabilitation after percutaneous endoscopic lumbar discectomy.

BACKGROUND: Percutaneous endoscopic lumbar discectomy (PELD) is a promising minimally invasive treatment for lumbar disc herniation (LDH). Postoperative rehabilitation can improve patient outcomes. Not only rehabilitation for surgical trauma but also rehabilitation for lumbar spine and lower kinetic chain dysfunction should be performed. The aims of this study were to investigate the efficacy of a lumbar kinetic chain training for staged rehabilitation after PELD for LDH. METHODS: Fifty one LDH patients treated with PELD were studied. After surgery, patients underwent lumbar kinetic chain training for staged rehabilitation( staged group) or regular low back rehabilitation (regular group). The staged rehabilitation programme included three phases from 2 to 6, 7-12, and 13-24 weeks postoperatively, and different physical therapies were performed during these phases. The low back pain visual analogue scale (VAS), JOA score, ODI, SF-36, and cross-sectional area of the lumbar multifidus on MRI were assessed, and gait analysis was performed. RESULTS: Twenty five patients in staged group and twenty six patients in regular group were included. There were no significant differences in age or sex between the two groups at baseline (p > 0.05). The VAS score decreased and the JOA and SF-36 scores increased in both groups from baseline to 6 weeks (P < 0.05). In the staged group, compared with the regular group, the VAS and ODI scores were lower and the JOA and SF-36 scores were higher at 6 weeks (P < 0.05); the VAS and ODI scores were lower and the SF-36 score was higher at 12 weeks (P < 0.05); the SF-36 score was higher at 24 weeks (P < 0.05); the cross-sectional area of the lumbar multifidus showed no differences at 12 weeks (P > 0.05); and the left-right support ratio of gait was higher at 24 weeks (P < 0.05). CONCLUSIONS: The staged rehabilitation programme for LDH after PELD promoted postoperative recovery, and the efficacy of lumbar kinetic chain training was higher than that of regular low back muscle exercise.

Okadaic Acid Exposure Induced Neural Tube Defects in Chicken (Gallus gallus) Embryos.

Okadaic acid (OA) is an important liposoluble shellfish toxin distributed worldwide, and is mainly responsible for diarrheic shellfish poisoning in human beings. It has a variety of toxicities, including cytotoxicity, embryonic toxicity, neurotoxicity, and even genotoxicity. However, there is no direct evidence of its developmental toxicity in human offspring. In this study, using the chicken (Gallus gallus) embryo as the animal model, we investigated the effects of OA exposure on neurogenesis and the incidence of neural tube defects (NTDs). We found that OA exposure could cause NTDs and inhibit the neuronal differentiation. Immunofluorescent staining of pHI3 and c-Caspase3 demonstrated that OA exposure could promote cell proliferation and inhibit cell apoptosis on the developing neural tube. Besides, the down-regulation of Nrf2 and increase in reactive oxygen species (ROS) content and superoxide dismutase (SOD) activity in the OA-exposed chicken embryos indicated that OA could result in oxidative stress in early chick embryos, which might enhance the risk of the subsequent NTDs. The inhibition of bone morphogenetic protein 4 (BMP4) and Sonic hedgehog (Shh) expression in the dorsal neural tube suggested that OA could also affect the formation of dorsolateral hinge points, which might ultimately hinder the closure of the neural tube. Transcriptome and qPCR analysis showed the expression of lipopolysaccharide-binding protein (LBP), transcription factor AP-1 (JUN), proto-oncogene protein c-fos (FOS), and C-C motif chemokine 4 (CCL4) in the Toll-like receptor signaling pathway was significantly increased in the OA-exposed embryos, suggesting that the NTDs induced by OA might be associated with the Toll-like receptor signaling pathway. Taken together, our findings could advance the understanding of the embryo-fetal developmental toxicity of OA on human gestation.

Minimum Seven-Year Follow-Up Outcomes of Percutaneous Endoscopic Lumbar Discectomy for Lumbar Degenerative Disease.

PURPOSE: To investigate the long-term (> 7 years) clinical outcomes of percutaneous endoscopic lumbar discectomy for lumbar degenerative disease to address postoperative problems including postoperative dysesthesia (POD), residual back pain and segmental instability. METHODS: Inclusion and exclusion criteria were established. All patients who met the above criteria were treated by PELD using the transforaminal approach. Limited discectomy was performed to preserve the disc material in the intervertebral space as much as possible. The Oswestry Disability Index (ODI), Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) score for back pain (VAS-B) and leg pain (VAS-L) and Modified MacNab's criterion were used for clinical evaluation. Radiographic parameters including height of intervertebral disc and segmental instability were also evaluated. RESULTS: Forty-two patients (24 men and 18 women) who met our inclusion and exclusion criteria were included in our study. The average follow-up period was 95.71±5.63 months (ranging from 87 to 105 months). There were no neurological complications associated with the operation. POD was found in 14.29% of patients, while only 2 patients (4.76%) complained of mild dysesthesia at final follow-up. Two patients (4.76%) required revision surgery during the follow-up period. The final follow-up ODI, JOA score, VAS-B and VAS-L were significantly better than preoperative values. The average disc-height ratio was 84.52±5.66% of the preoperative disc height. No instability at the operation level was noted at final follow-up. CONCLUSION: Our study showed that PELD using the transforaminal approach can provide favorable results after a long-term follow-up period. POD is a common complication at initial prognosis. Limited discectomy can preserve the disc height well and minimize the risk of residual back pain.

Allelopathy of Alexandrium pacificum on Thalassiosira pseudonana in laboratory cultures.

Alexandrium pacificum is a toxin-producing dinoflagellate with allelopathic effects. The elucidation of allelopathic mechanism of A. pacificum is of great significance for understanding A. pacificum blooms. To this end, using the model diatom Thalassiosira pseudonana as a target species, we observed changes in physiological, biochemical and gene transcription of T. pseudonana upon being co-cultured with A. pacificum. We found reciprocal effects between A. pacificum and T. pseudonana, and corroborated A. pacificum's allelopathy on T. pseudonana by observing inhibitory effects of filtrate from A. pacificum culture on the growth of T. pseudonana. We also found that co-culturing with A. pacificum, the expression of T. pseudonana genes related to photosynthesis, oxidative phosphorylation, antioxidant system, nutrient absorption and energy metabolism were drastically influenced. Coupled with the alterations in Fv/Fm (the variable/maximum fluorescence ratio), activity of superoxide dismutase, contents of malondialdehyde, neutral lipid and total protein in T. pseudonana co-cultured with A. pacificum, we propose that A. pacificum allelopathy could reduce the efficiency of photosynthesis and energy metabolism of T. pseudonana and caused the oxidative stress, while the nutrient absorption was also affected by allelopathic effects. The resultant data potentially uncovered the allelopathic molecular mechanism of A. pacificum to model alga T. pseudonana. The changes in nutrient uptake and even energy metabolism in T. pseudonana, as an adaptation to environmental conditions, may prevent it from stress-related injuries. Our finding might advance the understanding of allelopathic mechanism of A. pacificum.

Cinnamaldehyde Could Reduce the Accumulation of Diarrhetic Shellfish Toxins in the Digestive Gland of the Mussel Perna viridis under Laboratory Conditions.

Diarrhetic shellfish toxins (DSTs), some of the most important phycotoxins, are distributed almost all over the world, posing a great threat to human health through the food chain. Therefore, it is of great significance to find effective methods to reduce toxin accumulation in shellfish. In this paper, we observed the effects of four phytochemicals including cinnamaldehyde (CA), quercetin, oridonin and allicin on the accumulation of DSTs in the digestive gland of Perna viridis after exposure to the DSTs-producing Prorocentrum lima. We found that, among the four phytochemicals, CA could effectively decrease the accumulation of DSTs (okadaic acid-eq) in the digestive gland of P. viridis. Further evidence demonstrated that CA could reduce the histological alterations of the digestive gland of a mussel caused by DSTs. RT-qPCR showed that CA could suppress the CYP3A4 induction by DSTs, suggesting that the DSTs' decrease induced by CA might be related to the inhibition of CYP3A4 transcription induction. However, further studies on the underlying mechanism, optimal treatment time, ecological safety and cost should be addressed before cinnamaldehyde is used to decrease the accumulation of DSTs in field.

Increased sagittal diameter of the vertebral arch aids in diagnosis of lumbar spondylolysis.

OBJECTIVE: To identify a diagnostic indicator of lumbar spondylolysis visible in plain X-ray films. METHODS: One hundred and seventy-two patients with low back pain who received X-ray and computerized tomography (CT) examinations were identified and studied. They were divided into three groups: the spondylosis without spondylolisthesis (SWS) group, comprising 67 patients with bilateral pars interarticularis defects at L5 and without spondylolisthesis, the isthmic spondylolisthesis (IS) group, comprising 74 patients with L5/S1 spondylolisthesis and bilateral L5 pars interarticularis defects, and the control group, comprising 31 patients with low back pain but without spondylolysis. The sagittal diameters of the vertebral arch (SDVAs) of L4 and L5 were measured in lateral X-ray image, and the differences in SDVA between L4 and L5 (DSL4-5) in each case were calculated and analyzed. RESULTS: There were no significant differences in demographic characteristics among the three groups. In the SWS and IS groups, the SDVA of L5 was significantly longer than the SDVA of L4 (p < 0.001), whereas no significant difference found in the control group (p > 0.05). DSL4-5, in which the SDVA of L4 was subtracted from the SDVA of L5, significantly differed among the three groups (p < 0.001), and the normal threshold was provisionally determined to be 1.55 mm. CONCLUSIONS: In bilateral L5 spondylolysis, the SDVA of L5 is wider than the SDVA of L4, and this difference is greater in isthmic spondylolisthesis. This sign in lateral X-rays may provide a simple and convenient aid for the diagnosis of spondylolysis.

Responses of cytochrome P450, GST and MXR in the mussel Perna viridis to the exposure of Aureococcus anophagefferens.

The brown tide formed by a microscopic alga called Aureococcus anophagefferens has a devastating effect on filter-feeding bivalves, however, the related toxic principle remains an open question. In this study, we found that A. anophagefferens cells could motivate detoxification associated genes including CYP450, GST, P-gp and MVP, and induce SOD activity in the mussel Perna viridis. D1-like and D2-like receptors were expressed at high level in the gills of P. viridis, however, D2-like receptor transcript was too low to detect in digestive gland. The exposure of A. anophagefferens did not lead to any significant alterations in the expression of D1-like and D2-like receptors in both gills and digestive gland. These findings suggested that A. anophagefferens exhibited cytotoxicity toward bivalves, but did not obviously disrupt the dopamine system at transcriptional level in the acute exposure. Further studies are warranted to explore the nature of toxic compounds in A. anophagefferens affected bivalves.

TAG pathway engineering via GPAT2 concurrently potentiates abiotic stress tolerance and oleaginicity in Phaeodactylum tricornutum.

BACKGROUND: Despite the great potential of marine diatoms in biofuel sector, commercially viable biofuel production from native diatom strain is impractical. Targeted engineering of TAG pathway represents a promising approach; however, recruitment of potential candidate has been regarded as critical. Here, we identified a glycerol-3-phosphate acyltransferase 2 (GPAT2) isoform and overexpressed in Phaeodactylum tricornutum. RESULTS: GPAT2 overexpression did not impair growth and photosynthesis. GPAT2 overexpression reduced carbohydrates and protein content, however, lipid content were significantly increased. Specifically, TAG content was notably increased by 2.9-fold than phospho- and glyco-lipids. GPAT2 overexpression elicited the push-and-pull strategy by increasing the abundance of substrates for the subsequent metabolic enzymes, thereby increased the expression of LPAAT and DGAT. Besides, GPAT2-mediated lipid overproduction coordinated the expression of NADPH biosynthetic genes. GPAT2 altered the fatty acid profile in TAGs with C16:0 as the predominant fatty acid moieties. We further investigated the impact of GPAT2 on conferring abiotic stress, which exhibited enhanced tolerance to hyposaline (70%) and chilling (10 ºC) conditions via altered fatty acid saturation level. CONCLUSIONS: Collectively, our results exemplified the critical role of GPAT2 in hyperaccumulating TAGs with altered fatty acid profile, which in turn uphold resistance to abiotic stress conditions.

Ischemic damage may play an important role in spinal cord injury during dancing.

STUDY DESIGN: Retrospective analysis. SETTING: China Rehabilitation Research Center, Beijing, China. OBJECTIVE: To explore possible mechanisms underlying spinal cord injury (SCI) in children caused by hyperextension of the spine while dancing. METHODS: The clinical records of 88 children with SCI (mean age, 5.97 years; age range, 4-10 years) admitted to our hospital from January 1989 to October 2019 were retrospectively reviewed. Computed tomography and magnetic resonance imaging were performed on the day of injury. The time from injury to development of paralysis, as well as post-injury activities were surveyed, while abnormal patterns on images, the range of the involved vertebrae, and the extents of edema and atrophy were assessed. RESULTS: Among the 88 patients, 6 (6.8%) were unable to move immediately after SCI, while paralysis occurred in 42, 23, and 17 patients at <30, 30-60, and >60 min after SCI, respectively. The neurological level of injury of 84 patients was between T4 and T12. On sagittal T2-weighted images (T2WIs), the longitudinal range of spinal cord edema was more than one vertebral body in 65 patients, while spinal cord atrophy below T8 was found in 40 patients. On axial T2WIs, although three patients had none, long T2 signals were found in the central gray matter of seven patients. Meanwhile, necrosis of the central area combined with the peripheral white matter was observed in 57 patients, while three patients had total involvement on a cross section. CONCLUSION: Ischemia-related damage, rather than direct trauma to the spinal cord, may play an important role in SCI due to spinal hyperextension during dancing.

Changes in colonic microbiotas in rat after long-term exposure to low dose of okadaic acid.

Okadaic acid (OA), one of the most important phycotoxins, is widely distributed around the world, concerning diarrheic shellfish poisoning (DSP), and even colorectal cancer. Here, we found that long-term exposure of OA at a low dose (80 µg kg-1 body weight) had certain effects on colonic microbiotas and tract in rat. In the OA-exposed rat, colonic epithelium layer was damaged, and relative abundance of some microbiotas were significantly changed, especially genera in Clostridiales. However, no intestinal inflammation or significant disease was observed. Combined with the increase in relative abundance of some genera in Clostridiales induced by OA in the fermentation experiment, we proposed that OA could cause damage to the intestinal epithelium and increase the relative abundance of pathogenic bacteria, thereby increasing the probability of contact between intestinal epithelium and pathogenic bacteria and leading to an easier pathogenicity.

De novo transcriptome analysis of the mussel Perna viridis after exposure to the toxic dinoflagellate Prorocentrum lima.

Diarrheic shellfish poisoning (DSP) toxins are produced by harmful microalgae and accumulate in bivalve mollusks, causing various toxicity. These toxic effects appear to abate with increasing DSP concentration and longer exposure time, however, the underlying mechanisms remain unclear. To explore the underlying molecular mechanisms, de novo transcriptome analysis of the digestive gland of Perna viridis was performed after Prorocentrum lima exposure. RNA-seq analysis showed that 1886 and 237 genes were up- and down-regulated, respectively after 6 h exposure to P. lima, while 265 genes were up-regulated and 217 genes were down-regulated after 96 h compared to the control. These differentially expressed genes mainly involved in Nrf2 signing pathways, immune stress, apoptosis and cytoskeleton, etc. Combined with qPCR results, we speculated that the mussel P. viridis might mainly rely on glutathione S-transferase (GST) and ABC transporters to counteract DSP toxins during short-term exposure. However, longer exposure of P. lima could activate the Nrf2 signaling pathway and inhibitors of apoptosis protein (IAP), which in turn reduced the damage of DSP toxins to the mussel. DSP toxins could induce cytoskeleton destabilization and had some negative impact on the immune system of bivalves. Collectively, our findings uncovered the crucial molecular mechanisms and the regulatory metabolic nodes that underpin the defense mechanism of bivalves against DSP toxins and also advanced our current understanding of bivalve defense mechanisms.

Glucose-6-Phosphate Dehydrogenase from the Oleaginous Microalga Nannochloropsis Uncovers Its Potential Role in Promoting Lipogenesis.

Microalgae have long been considered as potential biological feedstock for the production of wide array of bioproducts, such as biofuel feedstock because of their lipid accumulating capability. However, lipid productivity of microalgae is still far below commercial viability. Here, a glucose-6-phosphate dehydrogenase from the oleaginous microalga Nannochloropsis oceanica is identified and heterologously expressed in the green microalga Chlorella pyrenoidosa to characterize its function in the pentose phosphate pathway. It is found that the G6PD enzyme activity toward NADPH production is increased by 2.19-fold in engineered microalgal strains. Lipidomic analysis reveals up to 3.09-fold increase of neutral lipid content in the engineered strains, and lipid yield is gradually increased throughout the cultivation phase and saturated at the stationary phase. Moreover, cellular physiological characteristics including photosynthesis and growth rate are not impaired. Collectively, these results reveal the pivotal role of glucose-6-phosphate dehydrogenase from N. oceanica in NADPH supply, demonstrating that provision of reducing power is crucial for microalgal lipogenesis and can be a potential target for metabolic engineering.