Combined treatment of human mesenchymal stem cells and green tea extract on retinal ganglion cell regeneration in rats after optic nerve injury.

Retinal ganglion cell (RGC) death and axonal loss cause irreversible vision loss upon optic nerve (ON) injury. We have independently demonstrated that mesenchymal stem cells (MSCs) and green tea extract (GTE) promote RGC survival and axonal regeneration in rats with ON injury. Here we aimed to evaluate the combined treatment effect of human bone marrow-derived MSCs (hBM-MSCs) and GTE on RGC survival and axonal regeneration after ON injury. Combined treatment of hBM-MSCs and GTE promoted RGC survival and neurite outgrowth/axonal regeneration in ex vivo retinal explant culture and in rats after ON injury. GTE increased Stat3 activation in the retina after combined treatment, and enhanced brain-derived neurotrophic factor secretion from hBM-MSCs. Treatment of 10 µg/mL GTE would not induce hBM-MSC apoptosis, but inhibited their proliferation, migration, and adipogenic and osteogenic differentiation in vitro with reducing matrix metalloproteinase secretions. In summary, this study revealed that GTE can enhance RGC protective effect of hBM-MSCs, suggesting that stem cell priming could be a prospective strategy enhancing the properties of stem cells for ON injury treatment.

Efficacy and Mechanism Study of 6S-5-Methyltetrahydrofolate-Calcium Against Telencephalon Infarction Injury in Zebrafish Model of Ischemic Stroke.

Ischemic stroke is a heterogeneous brain injury with complex pathophysiology and it is also a time sensitive neurological injury disease. At present, the treatment options for ischemic stroke are still limited. 6S-5-methyltetrahydrofolate-calcium (MTHF-Ca) is the calcium salt of the predominant form of dietary folate in circulation. MTHF-Ca has potential neuroprotective effect on neurocytes, but whether it can be used for ischemic stroke treatment remains unknown. We established zebrafish ischemic stroke model through photothrombotic method to evaluate the protective effect of MTHF-Ca on the ischemic brain injury of zebrafish. We demonstrated that MTHF-Ca reduced the brain damage by reducing motor dysfunction and neurobehavioral defects of zebrafish with telencephalon infarction injury. MTHF-Ca counteracted oxidative damages after Tel injury by increasing the activities of GSH-Px and SOD and decreasing the content of MDA. RNA-seq and RT-qPCR results showed that MTHF-Ca played a neuroprotective role by alleviating neuroinflammation, inhibiting blood coagulation, and neuronal apoptosis processes. Overall, we have demonstrated that MTHF-Ca has neuroprotective effect in ischemic stroke and can be used as a potential treatment for ischemic stroke.

Anti-inflammatory effects of 6S-5-methyltetrahydrofolate-calcium on RAW264.7 cells and zebrafish.

AIM: 6S-5-methyltetrahydrofolate is the predominant form of dietary folate in circulation and is used as a crystalline form of calcium salt (MTHF-Ca). Reports revealed that MTHF-Ca was more safe than folic acid, a synthetic and highly stable version of folate. Folic acid has been reported to have anti-inflammatory effects. The study's objective was to assess the anti-inflammatory effect of MTHF-Ca in vitro and in vivo. MAIN METHODS: In vitro, the ROS production was assessed by H2DCFDA, and nuclear translocation of NF-κB were evaluated by the NF-κB nuclear translocation assay kit. Interleukin-6 (IL-6), interleukin-1ß (IL-1ß), and tumor necrosis factor-alpha (TNF-α) were assessed using ELISA. In vivo, ROS production was assessed by H2DCFDA, neutrophils and macrophages recruitment were evaluated in tail transection-induced and CuSO4-induced zebrafish inflammation models. Expression of inflammation related genes were also investigated based on CuSO4-induced zebrafish inflammation model. KEY FINDINGS: MTHF-Ca treatment decreased LPS-induced ROS production, inhibited nuclear translocation of NF-κB and decreased the levels of IL-6, IL-1ß and TNF-α in RAW264.7 cells. In addition, MTHF-Ca treatment inhibited ROS production, suppressed the recruitment of neutrophils and macrophages, and reduced the expression of inflammation related genes, including jnk, erk, nf-κb, myd88, p65, tnf-α, and il-1b in zebrafish larvae. SIGNIFICANCE: MTHF-Ca may play an anti-inflammatory role by reducing the recruitment of neutrophils and macrophages and keeping the low levels of proinflammatory mediators and cytokines. MTHF-Ca may have a potential role in the treatment of inflammatory diseases.

Fecal microbiota transplantation inhibits colorectal cancer progression: Reversing intestinal microbial dysbiosis to enhance anti-cancer immune responses.

Many lines of evidence demonstrate the associations of colorectal cancer (CRC) with intestinal microbial dysbiosis. Recent reports have suggested that maintaining the homeostasis of microbiota and host might be beneficial to CRC patients, but the underlying mechanisms remain unclear. In this study, we established a CRC mouse model of microbial dysbiosis and evaluated the effects of fecal microbiota transplantation (FMT) on CRC progression. Azomethane and dextran sodium sulfate were used to induce CRC and microbial dysbiosis in mice. Intestinal microbes from healthy mice were transferred to CRC mice by enema. The vastly disordered gut microbiota of CRC mice was largely reversed by FMT. Intestinal microbiota from normal mice effectively suppressed cancer progression as assessed by measuring the diameter and number of cancerous foci and significantly prolonged survival of the CRC mice. In the intestine of mice that had received FMT, there were massive infiltration of immune cells, including CD8+ T and CD49b+ NK, which is able to directly kill cancer cells. Moreover, the accumulation of immunosuppressive cells, Foxp3+ Treg cells, seen in the CRC mice was much reduced after FMT. Additionally, FMT regulated the expressions of inflammatory cytokines in CRC mice, including down-regulation of IL1a, IL6, IL12a, IL12b, IL17a, and elevation of IL10. These cytokines were positively correlated with Azospirillum_sp._47_25, Clostridium_sensu_stricto_1, the E. coli complex, Akkermansia, Turicibacter, and negatively correlated with Muribaculum, Anaeroplasma, Candidatus_Arthromitus, and Candidatus Saccharimonas. Furthermore, the repressed expressions of TGFb, STAT3 and elevated expressions of TNFa, IFNg, CXCR4 together promoted the anti-cancer efficacy. Their expressions were positively correlated with Odoribacter, Lachnospiraceae-UCG-006, Desulfovibrio, and negatively correlated with Alloprevotella, Ruminococcaceae UCG-014, Ruminiclostridium, Prevotellaceae UCG-001 and Oscillibacter. Our studies indicate that FMT inhibits the development of CRC by reversing gut microbial disorder, ameliorating excessive intestinal inflammation and cooperating with anti-cancer immune responses.

Novel cinnamic acid derivatives as a versatile tool for developing agrochemicals for controlling plant virus and bacterial diseases by enhancing plant defense responses.

BACKGROUND: Plant pathogens have led to large yield and quality losses in crops worldwide. The discovery and study of novel agrochemical alternatives based on the chemical modification of bioactive natural products is a highly efficient approach. Here, two series of novel cinnamic acid derivatives incorporating diverse building blocks with alternative linking patterns were designed and synthesized to identify their antiviral capacity and antibacterial activity. RESULTS: The bioassay results demonstrated that most cinnamic acid derivatives had excellent antiviral competence toward tobacco mosaic virus (TMV) in vivo, especially compound A5 (median effective concentration [EC50 ] = 287.7 µg mL-1 ), which had a notable protective effect against TMV when compared with the commercial virucide ribavirin (EC50  = 622.0 µg mL-1 ). In addition, compound A17 had a protective efficiency of 84.3% at 200 µg mL-1 against Xac in plants. Given these outstanding results, the engineered title compounds could be regarded as promising leads for controlling plant virus and bacterial diseases. Preliminary mechanistic studies suggest that compound A5 could enhance the host's defense responses by increasing the activity of defense enzymes and upregulating defense genes, thereby suppressing phytopathogen invasion. CONCLUSION: This research lays a foundation for the practical application of cinnamic acid derivatives containing diverse building blocks with alternative linking patterns in pesticide exploration. © 2023 Society of Chemical Industry.

Novel spiro[chromanone-2,4'-piperidine]-4-one derivatives as potential inhibitors of fatty acid synthesis in pathogens: Design, synthesis, and biological evaluation.

Bacterial survival depends on membrane lipid homeostasis that enables to regulate lipid composition to adapt and optimize their growth in diverse environments. Therefore, the development of inhibitors that interfere with the bacterial fatty acid synthesis process is considered to be a promising tactic. In this study, 58 novel spirochromanone derivatives were prepared and their structure-activity relationship (SAR) was investigated. The bioassay results showed that all most of the compounds showed excellent biological activities, exampled by compounds B14, C1, B15, and B13, which had outstanding inhibitory activities toward various pathogenic bacteria with EC50 values of 0.78 µg/mL ∼3.48 µg/mL. Preliminary antibacterial behavior was studied by a series of biochemical assays including, but not limited to, fluorescence imaging patterns, GC-MS analysis, TEM images, and fluorescence titration experiments. Notably, compound B14 decreased the lipid content of the cell membrane, and increased cell membrane permeability, thereby destroying the integrity of the bacterial cell membrane. Further qRT-PCR results indicated that compound B14 interfered with the mRNA expression levels of fatty acid synthesis process-related genes including ACC, ACP, and Fab family genes. Herein, we highlight the promising bactericidal skeleton based on the spiro[chromanone-2,4'-piperidine]-4-one as a potential inhibitor of fatty acid synthesis.

Efficacy and mechanism study of cordycepin against brain metastases of small cell lung cancer based on zebrafish.

BACKGROUND: Small cell lung cancer (SCLC) is an aggressive tumor with high brain metastasis (BM) potential. There has been no significant progress in the treatment of SCLC for more than 30 years. Cordycepin has shown the therapeutic potential for cancer by modulating multiple cellular signaling pathways. However, the effect and mechanism of cordycepin on anti-SCLC BM remain unknown. PURPOSE: In this study, we focused on the anti-SCLC BM effect of cordycepin in the zebrafish model and its potential mechanism. STUDY DESIGN AND METHODS: A SCLC xenograft model based on zebrafish embryos and in vitro cell migration assay were established. Cordycepin was administrated by soaking and microinjection in the zebrafish model. RNA-seq assay was performed to analyze transcriptomes of different groups. Geno Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment were performed to reveal the underlying mechanism. Real-time qPCR was used to verify the effects of cordycepin on the key genes. RESULTS: Cordycepin showed lower cytotoxicity in vitro compared with cisplatin, anlotinib and etoposide, but showed comparable anti-proliferation and anti-BM effects in zebrafish SCLC xenograft model. Cordycepin showed significant anti-SCLC BM effects when administrated by both soaking and microinjection. RNA-seq demonstrated that cordycepin was involved in vitamin D metabolism, lipid transport, and proteolysis in cellular protein catabolic process pathways in SCLC BM microenvironment in zebrafish, and was involved in regulating the expressions of key genes such as cyp24a1, apoa1a, ctsl. The anti-BM effect of cordycepin in SCLC was mediated by reversing the expression of these genes. CONCLUSION: Our work is the first to describe the mechanism of cordycepin against SCLC BM from the perspective of regulating the brain microenvironment, providing new evidence for the anti-tumor effect of cordycepin.

Introducing the thin and ultrathin submental artery perforator flaps for precise reconstruction following T1-2 oral cavity cancer resection.

We reported a case series of thin (n = 32) and ultrathin (n = 4) submental artery perforator flaps (SMAPF) for precise reconstruction following T1-2 oral cavity cancer resection. The former is indicated for tongue reconstruction involving the tongue tip, and buccal lining replacement involving the mouth corner, while the latter is specifically tailored to restore superficial buccal defects after resection of small early cancer originating from oral submucous fibrosis. All flaps survived. Most flap reconstructions reached satisfactory cosmetic results. Based on this series, we discussed the indications of thin and ultrathin SMAPFs in intaoral reconstruction, and surgical tips for flap thinning.

Long-Noncoding RNA MANCR is Associated With Head and Neck Squamous Cell Carcinoma Malignant Development and Immune Infiltration.

Recent studies have demonstrated an important role for mitotically associated long non-coding RNA (MANCR) in carcinogenesis and cancer progression, but its function has not been elucidated in head and neck squamous cell carcinoma (HNSCC). In this study, we identified differentially expressed MANCR from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) databases across 24 cancer types and included 546 HNSCC patients. Furthermore, high expression of MANCR was verified in HNSCC cell lines and tissue by using real-time quantitative PCR (RT-qPCR) analysis. The Kaplan-Meier analysis showed a worse prognosis with higher levels of MANCR for HNSCC. The univariate Cox regression and multivariate Cox regression analyses revealed that MANCR was a high-risk factor in patients with HNSCC. Thereafter, we carried out the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. It was indicated that MANCR participates in axonogenesis and ECM-receptor interaction. Further enrichment analysis demonstrated that the expression of MANCR was positively correlated with the T gamma delta (tgd) cells, neutrophils, and Th1 cells, and negatively correlated with the infiltration of B cells, CD8 T cells, and T cells in HNSCC. In addition, in vitro experiments showed that knockdown of MANCR in HNSCC cells markedly inhibited cell proliferation, migration, and invasion. We find that MANCR was elevated in HNSCC and promoted the malignant progression of HNSCC. MANCR may serve as a potential biomarker in prognostic implications for HNSCC patients. The positive correlation between MANCR and immune infiltration cells may provide novel therapeutic targets and personalized immune-based cancer therapy for HNSCC.

High-quality nursing care on psychological disorder in ovarian cancer during perioperative period: A systematic review and meta-analysis.

BACKGROUND: This study aimed to explore the effect of high-quality nursing care (HQNC) on psychological disorder in patients with ovarian cancer (OC) during the perioperative period (PPP). METHODS: A literature search was performed at the Cochrane Library, PUBMED, Excerpt Medica Database, China National Knowledge Infrastructure, and Chinese Biomedical Literature Database from their inception until March 1, 2022. Two authors independently performed study selection, data collection, and methodological quality evaluation. The outcomes were anxiety (as measured by the Self-rating Anxiety Scale), depression (as measured by Self-rating Depression Scale), length of hospital stay, and rate of patient satisfaction. RESULTS: Eight trials involving 742 patients with OC were included in this study. Results of the data analysis showed that patients who received HQNC had a more promising effect on anxiety relief (mean difference, -9.00; random 95% confidence interval, -11.36 to -6.63; P < .001) and depression decrease (mean difference, -7.62; random 95% confidence intervals, -8.45 to -6.78; P < .001) than patients who underwent routine nursing care. CONCLUSION: This study summarized the latest evidence of HQNC on psychological disorder relief in patients with OC during perioperative period. These findings showed that HQNC may benefit patients with anxiety and depression.

Malignant Hyperthermia: A Killer If Ignored.

Malignant hypothermia (MH) is a potentially fatal hypermetabolic reaction of skeletal muscle. It is an autosomal dominant disorder that generally occurs in people with RYR1, CACNA1S, or STAC3 mutations. And these genetic abnormalities often cause the imperfection of calcium release channels of skeletal muscle. The incidence of MH among different racial groups across the world ranges from approximately 1:5,000-1:250,000, but there is no national statistic MH incidence in China. It is not clear whether there are racial or regional differences in the incidence, but patients under 18 years old may be more affected. MH can be triggered by anesthetics, or other stimuli, such as strenuous exercise, heat-stroke, and emotional stress. While viral infection, statins, hyperglycemia, and muscle metabolic dysfunctions might accelerate the onset of MH. The onset of MH is insidious and rapid, with the preclinical stage characterized by rigidity of the masseter muscle, a high level of end-tidal carbon dioxide, and a sharp and persistent increase in body temperature. Medical history, family history, clinical presentation, in vitro caffeine-halothane contracture testing (IVCT/CHCT) and genetic testing are commonly diagnostic methods of MH. As soon as the onset of MH is suspected, immediate cessation of exposure to stimuli, call for professional support, and access to dantrolene are the highest priorities. For symptomatic treatment, "5C principles" were summarized as an algorithm to guide clinicians.

Visualization of Literature Information on Postmortem Interval Estimation Indexed by CNKI Database from 1990 to 2020 / 法医学杂志

OBJECTIVES@#To explore the development process of the postmortem interval (PMI) research in China from January 1990 to August 2020, research hotspots in different periods, authors and cooperation between institutions, and to provide a reference for the better development of PMI inference research through the visualization of the literature information of the PMI estimation research indexed in China National Knowledge Infrastructure (CNKI).@*METHODS@#The information visualization analysis software CiteSpace 5.7.R1 was used to carry out big data analysis on hotspots, high-frequency keywords, authors, institutions and other information in the research literature on PMI inference from January 1990 to August 2020 indexed in CNKI.@*RESULTS@#The peak time of publication of PMI was from 2006 to 2010 with 114 articles. In keyword co-occurrence network, the effective hot words were forensic entomology, DNA content analysis and some emerging words such as artificial intelligence and big data. In the cooperation network of institutions, the high-frequency institutions were mainly the scientific research institutions. The author cooperation network showed a trend of co-aggregation and multi-cooperation.@*CONCLUSIONS@#With the development of science and technology, the research on PMI estimation based on traditional methods is mature and novel strategies are emerging. Big data and artificial intelligence combined with forensic science provide new research directions on PMI estimation.

Ectopic expression of MELK in oral squamous cell carcinoma and its correlation with epithelial mesenchymal transition.

Epithelial-mesenchymal transition (EMT) is closely correlated to metastasis formation generation and maintenance of cancer stem cells, nevertheless, the underlying mechanisms are unclear. The aim of this study is to investigate the role of maternal embryonic leucine-zipper kinase (MELK) in EMT regulation in oral squamous cell carcinoma (OSCC). We found that there was overexpression of MELK in human OSCC tissues, and high MELK expression was correlated with lymphatic metastasis and led to poor prognosis in patients with OSCC. We also confirmed that MELK is closely correlated to the EMT process using a human OSCC tissue microarray. Additionally, MELK expression was observed to be regulated in several OSCC cell lines, and knockdown of MELK genes inhibited cell proliferation, migration, invasion and EMT of OSCC cells in vitro. Furthermore, silencing of MELK suppressed tumour growth in vivo, and experimental research verified that MELK may augment OSCC development via mediating the Wnt/Notch signalling pathway. Our findings suggest that MELK serves as an oncogene to improve malignant development of OSCC via enhancing EMT, and MELK might be a potential target for anticancer therapeutic.

CircHIPK3: Key Player in Pathophysiology and Potential Diagnostic and Therapeutic Tool.

A large number of studies in China and other countries have confirmed that circularHIPK3 (circHIPK3) plays an important role in the pathophysiological processes of various diseases. Through the action of sponge miRNA (miR), circHIPK3 regulates cell proliferation, differentiation, and migration, and plays a key role in disease processes. By referring to a large number of research reports, this article explores the specific functional role of circHIPK3 in fibrotic diseases, cancer, and other diseases. This review aims to clarify the role of circHIPK3 in disease processes in order to aid further studies into the specific pathogenesis and clinical diagnosis of various diseases and provide new ideas for treatments.

Trickle-Down Effects of Entrepreneurial Bricolage and Business Model Innovation on Employee Creativity: Evidence From Entrepreneurial Internet Firms in China.

Although most existing studies have considered entrepreneurial bricolage as a means to overcome resource constraints in new ventures, few have explored the direct effects of entrepreneurial bricolage on employee creativity, particularly in the context of entrepreneurial internet firms. Drawing from multiple theories (i.e., social learning theory and social cognitive theory), this study proposes a cross-level mediation model for the trickle-down effects of entrepreneurial bricolage and business model innovation on employee creativity. By using a 2-wave longitudinal design, survey data were collected from multiple sources, including 49 leaders and 336 employees from entrepreneurial internet firms in China. Multilevel structural equation modeling (MSEM) was applied to analyze the cross-level mediation model. The results show that both entrepreneurial bricolage and business model innovation failed to significantly and positively direct employee creativity. Furthermore, entrepreneurial bricolage exerted a cross-level influence on employee creativity that was sequentially transmitted through between-level business model innovation and within-level creative self-efficacy. The theoretical and managerial implications of these findings are also discussed.

Diagnostic value of circulating microRNA-208a in differentiation of preserved from reduced ejection fraction heart failure.

BACKGROUND: There is no satisfactory answer on the specific biomarker that might be used in differentiating heart failure with reduced EF (HFrEF), allowing for inadequacy of N-terminal prohormone brain natriuretic peptide (NT-proBNP). OBJECTIVES: We aim to evaluate the value of microRNA-208a in diagnosing HFrEF patients. METHODS: We included 120 HF patients and 60 healthy volunteers. Diagnostic values of NT-proBNP and miR-208a for HF patients versus controls and HFrEF versus HFpEF were described by area under curve (AUC), sensitivity and specificity. RESULTS: HFrEF patients had significantly higher miR-208a level (p<0.001). As for diagnosing HFrEF patients, additional use of miR-208a and NT-proBNP yielded a significantly higher AUC than NT-proBNP alone (0.83, 95% CI 0.76-0.90 vs. 0.73, 95% CI 0.64-0.82) and the sensitivity and specificity were raised to 68.0% and 90.2%. CONCLUSION: Use of miR-208a in combination with NT-proBNP may allow a more reliable method in diagnosing HFrEF patients.

Determination of Three Types of New Psychoactive Tryptamines in Blood by QuEChERS Combined with UPLC-MS/MS / 法医学杂志

Objective To establish a method combining QuEChERS and ultra-high liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） for rapid screening and testing of three types of new psychoactive tryptamines in human blood： 5-MeO-DALT, 5-MeO-MiPT and 5-MeO-DiPT. Methods The effects of the type of extractant, the type and dosage of salting-out agent, and the dosage of adsorbent on the test results of the three tryptamines were investigated. Blood samples were processed by QuEChERS method and then determined by UPLC-MS/MS. Results The linear relationships of 5-MeO-DALT, 5-MeO-MiPT and 5-MeO-DiPT in human blood were good in the range of 0.5-100, 0.5-100 and 0.2-100 ng/mL, respectively, with their coefficients higher than 0.99. The limits of detection （LODs） were 0.1-0.2 ng/mg. The recoveries ranged from 84.86% to 94.57%. Intra-day and inter-day precisions were good. Conclusion The method is simple, rapid, easy to operate and has a high recovery. It is suitable for the qualitative and quantitative study of tryptamines in blood and can provide the reference for public security organs to deal with related cases.

Fabrication of Boronized Ti6Al4V/HA Composites by Microwave Sintering in Mixed Gases.

The effect of atmosphere on the fabrication of boronized Ti6Al4V/hydroxyapatite (HA) composites was investigated by microwave sintering of the mixture of Ti6Al4V alloy, HA, and TiB2 powders at 1050 °C for 30 min in the mixed gases of Ar + N2, Ar + CO, and Ar + H2, respectively. The presence of N2, CO, and H2 in the atmosphere caused formations of TiN, TiC, and TiH2 in the composites, respectively, together with evident microstructural changes that determined the mechanical properties (compressive strength, compressive modulus, and Vickers microhardness) and wettabilities of the composites after sintering. It was found that the composite exhibited the best mechanical performance with compressive strength of 148.59 MPa, compressive modulus of 13.9 GPa, and Vickers microhardness of 300.39 HV by microwave sintering in the mixed gas of Ar + H2, followed by those obtained in the mixed gases of Ar + N2 and Ar + CO. All of the composites possessed desirable wettabilities, irrespective of the sintering atmosphere, as demonstrated by their very low water contact angles (≤31.9°). The results indicated that it is critical to control the extents of nitration and carbonization for maintaining the performance of the composites, especially the mechanical properties, whereas there is no strict requirement for the same objective using the mixed gas of Ar + H2 in which qualified composites could be obtained for implant applications.

Clustering-Triggered Efficient Room-Temperature Phosphorescence from Nonconventional Luminophores.

Pure organic room-temperature phosphorescence (RTP) and luminescence from nonconventional luminophores have gained increasing attention. However, it remains challenging to achieve efficient RTP from unorthodox luminophores, on account of the unsophisticated understanding of the emission mechanism. Herein, we propose a strategy to realize efficient RTP in nonconventional luminophores through incorporation of lone pairs together with clustering and effective electronic interactions. The former promotes spin-orbit coupling and boosts the consequent intersystem crossing, whereas the latter narrows energy gaps and stabilizes the triplets, thus synergistically affording remarkable RTP. Experimental and theoretical results of urea and its derivatives verify the design rationale. Remarkably, RTP from thiourea solids with unprecedentedly high efficiency of up to 24.5 % is obtained. Further control experiments testify the crucial role of through-space delocalization on the emission. These results will spur the future fabrication of nonconventional phosphors and advance the understanding of the underlying emission mechanism.

Retention Time and Ion Abundance Ratio of 8 Common Drugs (Poisons) by LC-MS/MS Qualitative Analysis / 法医学杂志

Objective To investigate the maximum allowable deviations of retention time and ion abundance ratio of the 8 common drugs (poisons) from 3 categories, poisons (methamphetamine, morphine, ketamine), benzodiazepines (estazolam, midazolam, diazepam, clonazepam) and barbiturates (phenobar-bital) in blood, by liquid chromatograpy-tandem mass spectrometry (LC-MS/MS) in forensic toxicology analysis. Methods The deviations of retention time and ion abundance ratio at 7 low mass concentrations, limit of detection (LOD), 2LOD, limit of quantitation (LOQ), 1.5LOQ, 2LOQ, 4LOQ and 6LOQ, were tested by LC-MS/MS after liquid-liquid extraction under the conditions of two chromatographic columns and three chromatographs. Results The deviation of absolute retention time of 98.11% of 8 drugs (poisons) in the blood samples was within the range of ± 0.05 min, and that of the relative retention time of 96.21% was within the range of±0.4%. The maximum deviation of the ion abundance ratio was highly correlated with the mass concentration. When the mass concentration of drugs (poisons) was LOQ or above, more than 95% of the absolute deviation and relative deviation of the ion abundance ratio were in the range of±25% and±40%, respectively; when the mass concentration was below LOQ, the range could be expanded to±35% and±50%, respectively. Conclusion It is recommended for the determination range of the absolute retention time deviation of 8 common drugs (poisons) to be±0.1 min and that of the relative retention time deviation to be±1.0%. The determination range of absolute deviation of the ion abundance ratio should be±25% when the mass concentration is LOQ or above, and the relative deviation should be±40%. When the mass concentration is below LOQ, the deviation determination range can be expanded to±35% and±50%, respectively.