Organ-level distribution tandem mass spectrometry analysis of three structural types of brassinosteroids in rapeseed.

Background: Brassinosteroids (BRs) are a class of naturally occurring steroidal phytohormones mediating a wide range of pivotal developmental and physiological functions throughout the plant's life cycle. Therefore, it is of great significance to determine the content and the distribution of BRs in plants.Regretfully, although a large number of quantitative methods for BRs by liquid chromatography-tandem mass spectrometry (LC-MS/MS) have been reported, the in planta distribution of BRs is still unclear because of their lower contents in plant tissues and the lack of effective ionizable groups in their chemical structures. Methods: We stablished a novel analytical method of BRs based on C18 cartridge solid-phase extraction (SPE) purification, 4-(dimethylamino)-phenylboronic acid (DMAPBA) derivatization, and online valve-switching system coupled with ultra-high performance liquid chromatography-electro spray ionization-triple quadrupole mass spectrometry (UHPLC-ESI-MS/MS). This method has been used to quantify three structural types of BRs (epibrassinolide, epicastasterone, and 6-deoxo-24-epicastaster one) in different organs of Brassica napus L. (rapeseed). Results: We obtained the contents of three structural types of BRs in various organ tissues of rapeseed. The contents of three BRs in rapeseed flowers were the highest, followed by tender pods. The levels of three BRs all decreased during the maturation of the organs. We outlined the spatial distribution maps of three BRs in rapeseed based on these results, so as to understand the spatial distribution of BRs at the visual level. Conclusions: Our results provided useful information for the precise in situ localization of BRs in plants and the metabolomic research of BRs in future work. The in planta spatial distribution of BRs at the visual level has been studied for the first time.

Green fabrication of high-performance silver nanoparticles/reduced Ti3C2TxMXene nanocomposite catalyst for 4-nitrophenol reduction.

The outstanding electrical conductivity of transition metal carbides Ti3C2Tx(MXene) makes it as an excellent electron transfer medium for fabrication of efficient catalysts. However, the poor stability of MXene may restrict its application. Herein, a novel silver nanoparticles/reduced MXene nanocomposite (AgNPs/rMXene) catalyst was prepared by using L-arginine (L-Arg) as a green reducing agent. In the AgNPs/rMXene catalyst, the silver nanoparticles (AgNPs) and reduced MXene (rMXene) acted as catalytic active species and electron transfer medium, respectively. The composite catalyst exhibited superior catalytic activity in the conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP), and the conversion frequency (TOF) was high up to 1109.4 h-1. Notably, the composite catalyst also showed high stability due to the reduction of L-Arg (i.e. the repair of defect groups on MXene surface). The conversion efficiency for 4-NP reduction by AgNPs/rMXene was high up to 90% after five recycles. This present study offers a simple and green approach for the design and development of efficient MXene-based catalysts.

The effectiveness of percutaneous endoscopic decompression compared with open decompression and fusion for lumbar spinal stenosis: protocol for a multicenter, prospective, cohort study.

BACKGROUND: Lumbar spinal stenosis (LSS) is one of the most frequent indications for spine surgery. Open decompression and fusion surgery was the most common treatment and used to be regarded as the golden standard treatment for LSS. In recent years, percutaneous endoscopic decompression surgery was also used for LSS. However, the effectiveness and safety of percutaneous endoscopic decompression in the treatment of LSS have not been supported by high-level evidence. Our aim is to 1) compare the effectiveness of percutaneous endoscopic decompression surgery and open decompression and fusion for the treatment of LSS. 2) Investigate the prognosis risk factors for LSS. 3) Evaluate the influence of percutaneous endoscopic decompression for the stability of operative level, and degeneration of adjacent level. METHODS: It's a prospective, multicenter cohort study. The study is performed at 4 centers in Beijing. This study plans to enroll 600 LSS patients (300 patients in the percutaneous endoscopic decompression group, and 300 patients in the open decompression and fusion group). The demographic variables, healthcare variables, symptom related variables, clinical assessment (Visual analogue score (VAS), Oswestry disability index (ODI), Japanese Orthopaedic Association score (JOA)), and radiological assessment (dynamic X-ray, CT, MRI) will be collected at baseline visit. Patients will follow up at 3, 6, 12 months. The primary outcome is the difference of improvement of ODI between baseline and 12-month follow-up between the two groups. The secondary outcome is the score changes of preoperative and postoperative VAS, the recovery rate of JOA, MacNab criteria, patient satisfaction, degeneration grade of adjacent level, ROM of operative level and adjacent level, complication rate. DISCUSSION: In this study, we propose to conduct a prospective registry study to address the major controversies of LSS decompression under percutaneous spinal endoscopy, and investigate the clinical efficacy and safety of percutaneous endoscopic decompression and open decompression in the treatment of LSS. TRIAL REGISTRATION: This study has been registered on clinicaltrials.gov in January 15, 2020 ( NCT04254757 ). (SPIRIT 2a).

Normative values of cervical sagittal alignment according to global spine balance: based on 126 asymptomatic Chinese young adults.

PURPOSE: To explore the normal distribution of cervical sagittal alignment and the relationship between cervical alignment and global spine balance in asymptomatic young adults. METHODS: A total of 67 males and 59 females aged from 18 to 30 years old were recruited from 11/2011 to 12/2014. The C0-C2 angle, disk angles from C2-C3 to C6-C7, vertebral angles from C3 to C7, T1 slope, thoracic kyphosis (TK), lumbar lordosis, pelvic incidence, sacral slope, C2-C7 sagittal vertical axis (SVA), center of gravity of head to C7 SVA (CGH-C7SVA), C7-S1SVA were measured and statistically analyzed. The Roussouly classification was utilized. RESULTS: Mean value of C0-C7 was 26.0° ± 12.8°, composed of 15.2° ± 6.7° for C0-C2, 9.1° ± 12.1° for sum of disk angles from C2-C3 to C6-C7, and 1.4° ± 10.2° for sum of vertebral angles from C3 to C7. C2-C7SVA (18.6 mm ± 7.9 mm) and CGH-C7SVA (22.9 mm ± 12.3 mm) were offset ideally by C7-S1SVA (-21.6 mm ± 31.0 mm). Significant difference was found between cervical alignment of different Roussouly types (p < 0.01). There was significant correlation between cervical alignment and T1 slope (p < 0.01), TK (p < 0.01). There was significant correlation between adjacent segmental angles from T1 slope up to C0-C2 angle (p < 0.05). CONCLUSION: Normative values of each vertebral angle and disk angle were established. The cervical lordosis occurred mainly at C0-C2 and disk levels, which was influenced by parameters of other parts of the spine, such as T1 slope, TK and the Roussouly classification. There was significant correlation between adjacent disk angles. LEVEL OF EVIDENCE I: Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Full-Endoscopic Lumbar Decompression versus Open Decompression and Fusion Surgery for the Lumbar Spinal Stenosis: A 3-Year Follow-Up Study.

PURPOSE: Compare the efficacy of full-endoscopic lumbar decompression surgery (FELDS) and open decompression and fusion surgery (ODFS) for lumbar spinal stenosis (LSS). PATIENTS AND METHODS: A retrospective analysis of 358 LSS patients treated by FELDS ("FELD" group) or ODFS ("open" group) was undertaken. There were 177 patients in the FELDS group with a mean age of 65.47±9.26 years and 181 patients in the open group with a mean age of 64.18±10.24 years. Duration of follow-up was 38.63±11.88 months in the FELDS group and 38.56±12.29 months in the open group. Visual analog scale (VAS) score, Oswestry Disability Index (ODI), and Modified MacNab criteria were used to access clinical outcomes. Surgical outcomes (duration of surgical procedure, blood loss, complications, duration of postoperative hospital stay (DOPHS), prevalence of revision procedures) were evaluated. Magnetic resonance imaging was used to evaluate the change in the Pfirrmann grade at adjacent segments. RESULTS: VAS score (leg and back) and ODI improved significantly in both groups (P<0.001). Success rate reached 86.55% and 90.60% in the FELDS group and open group (P>0.05), respectively. Procedure duration (84.12 vs 112.08 min), blood loss (7.97 vs 279.67 mL), and DOPHS (2.68 vs 4.78 days) of the FELDS group were significantly better than those of the open group (P<0.05). Total prevalence of complications and procedure revisions was 14.69% and 10.73% in the FELD group, respectively, but did not show a significant difference with that in the open group (12.15% and 9.39%, respectively). The Pfirrmann grade increased in 13.04% of adjacent segments in the FELDS group, significantly better than that in the open group (32.67%) (P<0.05). CONCLUSION: FELDS had the same efficacy as ODFS for LSS treatment. FELDS had the advantages of minimal invasiveness, less surgical trauma, rapid recovery, and lower risk of degeneration of adjacent segments compared with that of ODFS.

Full-Endoscopic Foraminotomy with a Novel Large Endoscopic Trephine for Severe Degenerative Lumbar Foraminal Stenosis at L5 S1 Level: An Advanced Surgical Technique.

To (i) introduce the technical notes of a novel full-endoscopic foraminotomy with a large endoscopic trephine for the treatment of severe degenerative lumbar foraminal stenosis at L5 S1 level; (ii) assess the primary clinical outcomes of this technique; (iii) compare the effectiveness of this full-endoscopic foraminotomy technique and other previous techniques for lumbar foraminal stenosis. From January 2019 to August 2019, a retrospective study of L5 S1 severe degenerative lumbar foraminal stenosis was performed in our center. All patients who were diagnosed with severe foraminal stenosis at L5 S1 level and failed conservative treatment for at least 6 weeks were identified. Patients with segmental instability or other coexisting contraindications were excluded. A total of 21 patients were enrolled in the study. All patients were treated by full-endoscopic foraminotomy using large endoscopic trephine. The visual analogue scale (VAS) and Oswestry disability index (ODI) were evaluated preoperatively and at 1, 3, 6 months, and 1 year after the surgery, and the modified MacNab criteria were used to evaluate clinical outcomes at the last follow-up. There were 10 males and 11 females with a mean age of 66.38 ± 9.51 years. Five patients had a history of lumbar surgery. The mean operative time was 63.57 ± 25.74 min. The mean follow-up time was 13.29 ± 1.38 months. The mean postoperative hospital stay time was 1.29 ± 0.56 days. The mean preoperative VAS score significantly decreased from 7.38 ± 1.02 to 2.76 ± 1.09 (t = 19.759, P < 0.01), 2.25 ± 1.02 (t = 21.508, P < 0.01), 1.60 ± 1.05 (t = 31.812, P < 0.01), and 1.45 ± 1.10 (t = 25.156, P < 0.01) at 1 month, 3 months, 6 months, and 1 year after the operation. The mean preoperative ODI score significantly decreased from 64.66% ± 4.91% to 30.69% ± 4.59% (t = 33.724, P < 0.01), 29.44% ± 4.50% (t = 32.117, P < 0.01), 24.22% ± 4.14% (t = 33.951, P < 0.01), and 22.44% ± 4.94% (t = 30.241, P < 0.01) at 1 month, 3 months, 6 months, and 1 year after the operation. At the last follow-up, 19 patients (90.48%) got excellent or good outcomes. One patient suffered postoperative dysesthesia, and the symptoms were controlled by conversion treatment. One patient took revision surgery due to the incomplete decompression. There were no other major complications. Percutaneous endoscopic decompression is minimally invasive spine surgery. However, the application of endoscopic decompression for L5 S1 foraminal stenosis is relatively difficult due to the high iliac crest and narrow foramen. Full-endoscopic foraminotomy with the large endoscopic trephine is an effective and safe technique for the treatment of degenerative lumbar foraminal stenosis.

Analysis of cervical and global spine alignment under Roussouly sagittal classification in Chinese cervical spondylotic patients and asymptomatic subjects.

PURPOSE: To explore the relationship between cervical spine and the global spine alignment and to postulate the hypotheses that a lordotic alignment of cervical spine is not the only standard to identify asymptomatic subjects, and the degenerative modification of cervical curves depends primarily on their spinal-pelvic alignment. METHODS: A cohort of 120 cases of Chinese asymptomatic subjects and a cohort of 121 cases of Chinese cervical spondylotic patients were recruited prospectively from 2011 to 2012. Roussouly Classification was utilized to categorize all subjects and patients according to their thoracic spine, lumbar spine and pelvic alignment. The cervical alignments were evaluated as lordosis, straight, sigmoid or kyphosis. Through the lateral X-ray images of neutral cervical and global spine, a number of parameters were measured and analyzed, including pelvic incidence, pelvic tilt, sacral slope, thoracic kyphosis (TK), lumbar lordosis, global cervical angles (angles between two lines parallel with posterior walls of C2 and C7), practical cervical angles (the addition of different cervical end plate angles from C3 to C7, and inter-vertebral angles from C23 to C67), T1 slope, spinal sacral angles (SSA), Hip to C7/Hip to Sacrum and C0-C2 angle. RESULTS: The percentages of cervical lordosis were 28.3% and 36.4% in asymptomatic and spondylotic group, respectively. The cervical spine alignments correlated with Roussouly types of global spine alignment in both asymptomatic and cervical spondylotic group (P < 0.001). And there were significant differences between Roussouly Type 2 and 4, Type 3 and 4, Type 1 and 3 in cervical angles in spondylotic group (P < 0.05). In the comparison of the two cohorts, significant differences were found in both general and practical cervical angles in Roussouly Type 4 (P = 0.00 and 0.01, respectively), and there were significant differences in inter-vertebral angle in Roussouly Type 2 at C4-5 and C5-6 levels (P = 0.04 and 0.04, respectively), and in Roussouly Type 3 at C6-7 level (P = 0.01). The SSA showed significant difference between Roussouly Type 2 and 4 in asymptomatic subjects (P = 0.00), and between Type 1 and 3, 1 and 4, 2 and 3, 2 and 4 in cervical spondylotic patients (P = 0.01, 0.02, 0.00 and 0.01, respectively). The T1 slope was significantly different among Roussouly types (P = 0.04) with its largest value in Type 1 in cervical spondylotic group. There are significant differences in C0-C2 angles in all Roussouly types (P = 0.01, 0.02, 0.00 and 0.01, respectively), as well as in the ratio of Hip to C7/hip to sacrum in Type 2 (P = 0.01), and Type 3 (P = 0.00) in the comparison of the two cohorts. The multiple linear regression of all parameters showed both general and practical cervical angles were significantly related to TK, C0-C2 and T1 slope (P = 0.01, 0.00 and 0.00, respectively). CONCLUSION: The cervical alignment correlates with their global spine and pelvic curves. And lordosis is not the only presentation in asymptomatic subjects. The degenerative modification of cervical disc angles was the compensation of global spine degeneration for horizontal gaze. Cervical angles are influenced by their TK angles, occipital-C2 joint and the tilt of T1 vertebral body. The occipital-C2 joint has a compensating mechanism in all Roussouly types in cervical spondylosis.

Effects and risk evaluation of oil spillage in the sea areas of Changxing Island.

This paper evaluated the oil spillage risk in the waters near the island of Changxing in Dalian (China) based on the established risk assessment index. Four wind regimes (windless, northerly wind, westerly wind and southerly wind) were selected as weather conditions for the dynamic prediction of oil drift. If an oil spill occurs near the Koumen (a place near the island of Changxing), the forecast and evaluation are conducted based on a three-dimensional mathematical model of oil spillage, and the results obtained show the scope of the affected area when winds from various directions are applied. The oil spillage would, under various conditions, flow into the northern and western sea area of Changxing Island Bay, namely the Dalian harbor seal National Nature Reserve, and create adverse effects on the marine ecological environment. The rationality of combining the established oil spillage risk comprehensive index system with model prediction is further confirmed. Finally, preventive measures and quick fixes are presented in the case of accidental oil spillages. The most effective method to reduce environment risk is to adopt reasonable preventive measures and quick fixes.

Common underlying diseases do not contribute in determining the causes of sudden unexplained death.

BACKGROUND: Underlying diseases have a statistically significant positive correlation to sudden death. However, sudden unexplained death (SUD) is different from sudden death, as there is no clinical evidence to support the sudden death due to the original underlying disease, nor a lethal pathological basis to be found during autopsy. In addition, SUD are more common in young, previously healthy individuals, usually without any signs of disease, with no positive lesions found after autopsy. Therefore, a causal relationship between SUD and the underlying disease needs to be further explored. This study aimed to explore the role that common underlying diseases play in patients with SUD and to reveal the correlation between them. METHODS: The medical records, history and case information of 208 patients with SUD were collected for the survey. All these SUD occurred in the emergency room of Peking University Third Hospital from January 2006 to December 2009. The patients were stratified by with and without common underlying diseases. To examine possible associations between the underlying diseases and the cause of unexplained sudden death, the chi-squared and Fisher's exact tests were used. RESULTS: Among the 208 patients, 65 were diagnosed with common underlying diseases while 143 were not. Within these two groups, there were 45 patients for whom the clear cause of death was determined. However, there were no statistically significant differences or strong associations (χ(2) = 1.238, P > 0.05) between the 11 patients with (16.90%) and 34 without (23.78%) common underlying disease among these 45 patients. We also found that occurrence of the common underlying diseases, such as neurological system, cardiovascular and pulmonary system diseases, are not statistically significant (P > 0.05) in the diagnosis of the SUD. CONCLUSION: Common underlying diseases make no obvious contributions to SUD and are not useful in diagnosing the underlying reasons for death.

Time-series analysis of the relationship between air quality, temperature, and sudden unexplained death in Beijing during 2005 - 2008.

BACKGROUND: There is a yearly increase in the rate of sudden unexplained death (SUD), even through extensive physical examination and the testing of a large number of biomarkers, the cause of sudden death in patients previously in good health cannot be fully determined. During clinical practice, a spatial aggregation phenomenon has been observed in the incidence of sudden unexplained death. Previous research has shown that environmental factors, such as air pollution, weather conditions, etc., have a significant impact on human health. In the wake of the continuous environmental damage, the relationship between environmental factors and sudden unexplained death still needs to be studied. To study the relationship between sudden unexplained death and air quality and temperature, commonly used markers such as particulate matter of aerodynamic diameter < 10 µm (PM(10)), daily average concentration of the gaseous pollutants sulfur dioxide (SO2) and nitrogen dioxide (NO2), and the daily average temperature were investigated. METHODS: The methods include collecting the data of sudden unexplained death; air quality monitoring; meteorological monitoring from January 1, 2005 to December 31, 2008; utilizing generalized additive models (GAM); controlling the influential factors such as secular trend, seasonal trend, and Sunday dummy variable; and analyzing the correlation between daily inhalable particle concentration, daily average temperature, and the number of daily SUD. RESULTS: There was no statistical significance between the daily inhalable particle and daily incidence of sudden unexplained death. Incidence rate of sudden unexplained death had nonlinear positive correlation with daily temperature. When the temperature was 5°C above the daily average temperature, the daily incidence of sudden unexplained death went up with the rising temperature. CONCLUSION: Temperature may be one of the key risk factor or precipitating factor of SUD.

Analysis of the prodromal symptoms of unexplained sudden death in patients with or without underlying diseases.

BACKGROUND: In recent years, the incidence of unexplained sudden death has risen significantly across the world. However, it occurred suddenly, often in young apparently healthy individuals and almost 50% of the patients did not have any warning signals or symptoms. Therefore, the prodromal symptoms before the incident are extremely important for early prediction of sudden death. In this article, we aimed to explore the value of prodromal symptoms for unexplained sudden death and whether the prodromal symptoms have a predictive function to unexplained sudden death (USD) without underlying diseases. METHODS: A total of 208 sudden death cases were selected for the survey in the Emergency Department of Peking University Third Hospital from January 2006 to December 2009 and their medical records were reviewed. The patients were divided into two groups, 65 patients had underlying diseases while 143 had not underlying diseases. In the meantime, their prodromal symptoms were collected and compared, prodromal symptoms including chest distress, dyspnea, syncope, fever, headache, vomiting, etc. RESULTS: Patients with underlying diseases were compared to those without underlying diseases associated with sudden death; there was no significant difference in gender and age distribution. Among the 208 cases, 39 cases (18.75%) had prodromal symptoms, patients with underlying diseases had prodromal symptoms in 12 cases (18.46%), while patients without underlying diseases had prodromal symptoms in 27 cases (18.88%). The difference between the two groups with prodromal symptoms was not statistically significant (P > 0.05). CONCLUSIONS: Prodromal symptoms are extremely important warning signals in the occurrence of USD. It has equally important predictive value for patients both with and without underlying diseases, especially in predicting sudden death caused by cardiopulmonary and neurological diseases.

[Effects of lead stress on anti-oxidative enzyme activities and isoenzymes in cucumber seedlings].

With hydroponics and polyacrylamide gel electrophoresis (PAGE), this paper studied the effects of lead stress on the activities of peroxidase (POD), superoxide dismutase (SOD) and catalase (CAT), and their isoenzymic band numbers in cucumber seedlings. The results showed that the isoenzymic bands and expression quantity of POD decreased gradually with increasing lead concentration. The SOD activity increased with increasing lead concentration within the range of 0-500 mg Pb x L(-1), reached the maximum at 7th day, and then decreased rapidly, being lower than the control of the same period. Under the concentration of 900 mg Pb x L(-1), the SOD activity decreased with time. The isoenzymic bands and expression quantity of SOD were negatively related to lead concentration. No significant change was observed in the isoenzymic bands of CAT, but a significant difference was found in the expression quantity of CAT isoenzymes.