Single-Photon Interference over 8.4 km Urban Atmosphere: Toward Testing Quantum Effects in Curved Spacetime with Photons.

The emergence of quantum mechanics and general relativity has transformed our understanding of the natural world significantly. However, integrating these two theories presents immense challenges, and their interplay remains untested. Recent theoretical studies suggest that the single-photon interference covering huge space can effectively probe the interface between quantum mechanics and general relativity. We developed an alternative design using unbalanced Michelson interferometers to address this and validated its feasibility over an 8.4 km free-space channel. Using a high-brightness single-photon source based on quantum dots, we demonstrated single-photon interference along this long-distance baseline. We achieved a phase measurement precision of 16.2 mrad, which satisfied the measurement requirements for a gravitational redshift at the geosynchronous orbit by 5 times the standard deviation. Our results confirm the feasibility of the single-photon version of the Colella-Overhauser-Werner experiment for testing the quantum effects in curved spacetime.

Prediction model for lymph node metastasis in superficial colorectal cancer: a better choice than computed tomography.

BACKGROUND: Risk evaluation of lymph node metastasis (LNM) in superficial colorectal cancer resected by endoscopic surgery is critical for determining subsequent therapeutic strategies, but the role of existing clinical methods, including computed tomography, remains limited. METHODS: Features of the nomogram were determined by logistic regression analysis, and the performance was validated by calibration plots, ROC curves and DCA curves in both the training set and the validation set. RESULTS: A total of 608 consecutive superficial CRC cases were randomly divided into 426 training and 182 validation cases. Univariate and multivariate logistic regression analyses revealed that age < 50, tumour budding, lymphatic invasion and lower HDL levels were risk factors for LNM. Stepwise regression and the Hosmer‒Lemeshow goodness of fit test showed that the nomogram had good performance and discrimination, which was validated by ROC curves and calibration plots. Internal and external validation demonstrated that the nomogram had a higher C-index (training group, 0.749, validation group, 0.693). DCA and clinical impact curves graphically show that the use of the nomogram to predict LNM had remarkable predictive power. Finally, in comparison with CT diagnosis, the nomogram also visually showed higher superiority, as demonstrated by ROC, DCA and clinical impact curves. CONCLUSION: Using common clinicopathologic factors, a noninvasive nomogram for individualized prediction of LNM after endoscopic surgery was conveniently established. Nomograms have great superiority in the risk stratification of LNM compared with traditional CT imaging.

Nomogram model for the risk of insulin resistance in obese children and adolescents based on anthropomorphology and lipid derived indicators.

OBJECTIVE: This study aims to screen for measures and lipid-derived indicators associated with insulin resistance (IR) in obese children and adolescents and develop a nomogram model for predicting the risk of insulin resistance. METHODS: A total of 404 eligible obese children and adolescents aged 10-17 years were recruited for this study from a summer camp between 2019 and 2021. The risk factors were screened using the least absolute shrinkage and selection operator (LASSO)-logistic regression model, and a nomogram model was developed. The diagnostic value of the model was evaluated by plotting the receiver operator characteristic curve and calculating the area under the curve. Internal validation was performed using the Bootstrap method, with 1000 self-samples to evaluate the model stability. The clinical applicability of the model was assessed by plotting the clinical decision curve. RESULTS: On the basis of the LASSO regression analysis results, three lipid-related derivatives, TG/HDL-c, TC/HDL-c, and LDL-c/HDL-c, were finally included in the IR risk prediction model. The nomogram model AUC was 0.804 (95% CI: 0.760 to 0.849). Internal validation results show a C-Index of 0.799, and the mean absolute error between the predicted and actual risks of IR was 0.015. The results of the Hosmer-Lemeshow goodness-of-fit test show a good model prediction (χ2 = 9.523, P = 0.300). CONCLUSION: Three early warning factors, TG/HDL-c, TC/HDL-c, and LDL-c/HDL-c, were screened, which can effectively predict the risk of developing IR in obese children and adolescents, and the nomogram model has an eligible diagnostic value.

The steroid hormone 20-hydroxyecdysone counteracts insulin signaling via insulin receptor dephosphorylation.

The insulin receptor (INSR) binds insulin to promote body growth and maintain normal blood glucose levels. While it is known that steroid hormones such as estrogen and 20-hydroxyecdysone counteract insulin function, the molecular mechanisms responsible for this attenuation remain unclear. In the present study, using the agricultural pest lepidopteran Helicoverpa armigera as a model, we proposed that the steroid hormone 20-hydroxyecdysone (20E) induces dephosphorylation of INSR to counteract insulin function. We observed high expression and phosphorylation of INSR during larval feeding stages that decreased during metamorphosis. Insulin upregulated INSR expression and phosphorylation, whereas 20E repressed INSR expression and induced INSR dephosphorylation in vivo. Protein tyrosine phosphatase 1B (PTP1B, encoded by Ptpn1) dephosphorylated INSR in vivo. PTEN (phosphatase and tensin homolog deleted on chromosome 10) was critical for 20E-induced INSR dephosphorylation by maintaining the transcription factor Forkhead box O (FoxO) in the nucleus, where FoxO promoted Ptpn1 expression and repressed Insr expression. Knockdown of Ptpn1 using RNA interference maintained INSR phosphorylation, increased 20E production, and accelerated pupation. RNA interference of Insr in larvae repressed larval growth, decreased 20E production, delayed pupation, and accumulated hemolymph glucose levels. Taken together, these results suggest that a high 20E titer counteracts the insulin pathway by dephosphorylating INSR to stop larval growth and accumulate glucose in the hemolymph.

N7 -SSPP fusion gene improves salt stress tolerance in transgenic Arabidopsis and soybean through ROS scavenging.

Considerable signal crosstalk exists in the regulatory network of senescence and stress response. Numerous senescence-associated genes are also involved in plant stress tolerance. However, the underlying mechanisms and application potential of these genes in stress-tolerant crop breeding remain poorly explored. We found that overexpression of SENESCENCE-SUPPRESSED PROTEIN PHOSPHATASE (SSPP), a negative regulator of leaf senescence, significantly improved plant salt tolerance by increasing reactive oxygen species (ROS) scavenging in both Arabidopsis and soybean. However, overexpression of SSPP severely suppressed normal plant growth, limiting its direct use in agriculture. We previously revealed that the N-terminal 1-14 residues of ACS7 (termed 'N7 ') negatively regulated its protein stability through the ubiquitin/proteasome pathway, and the N7 -mediated protein degradation was suppressed by environmental and senescence signals. To avoid the adverse effects of SSPP, the N7 element was fused to the N-terminus of SSPP. We demonstrated that N7 -SSPP fusion gene effectively rescued SSPP-induced growth suppression but maintained enhanced salt tolerance in Arabidopsis and soybean. Particularly, N7 -SSPP enhanced tolerance to long-term salt stress and increased seed yield in soybean. These results suggest that N7 -SSPP overcomes the disadvantages of SSPP on plant growth inhibition and effectively improves salt tolerance through enhanced ROS scavenging, providing an effective strategy of using posttranslational regulatory element for salt-tolerant crop breeding.

Very long intergenic non-coding (vlinc) RNAs directly regulate multiple genes in cis and trans.

BACKGROUND: The majority of the human genome is transcribed in the form of long non-coding (lnc) RNAs. While these transcripts have attracted considerable interest, their molecular mechanisms of function and biological significance remain controversial. One of the main reasons behind this lies in the significant challenges posed by lncRNAs requiring the development of novel methods and concepts to unravel their functionality. Existing methods often lack cross-validation and independent confirmation by different methodologies and therefore leave significant ambiguity as to the authenticity of the outcomes. Nonetheless, despite all the caveats, it appears that lncRNAs may function, at least in part, by regulating other genes via chromatin interactions. Therefore, the function of a lncRNA could be inferred from the function of genes it regulates. In this work, we present a genome-wide functional annotation strategy for lncRNAs based on identification of their regulatory networks via the integration of three distinct types of approaches: co-expression analysis, mapping of lncRNA-chromatin interactions, and assaying molecular effects of lncRNA knockdowns obtained using an inducible and highly specific CRISPR/Cas13 system. RESULTS: We applied the strategy to annotate 407 very long intergenic non-coding (vlinc) RNAs belonging to a novel widespread subclass of lncRNAs. We show that vlincRNAs indeed appear to regulate multiple genes encoding proteins predominantly involved in RNA- and development-related functions, cell cycle, and cellular adhesion via a mechanism involving proximity between vlincRNAs and their targets in the nucleus. A typical vlincRNAs can be both a positive and negative regulator and regulate multiple genes both in trans and cis. Finally, we show vlincRNAs and their regulatory networks potentially represent novel components of DNA damage response and are functionally important for the ability of cancer cells to survive genotoxic stress. CONCLUSIONS: This study provides strong evidence for the regulatory role of the vlincRNA class of lncRNAs and a potentially important role played by these transcripts in the hidden layer of RNA-based regulation in complex biological systems.

Heralded Nondestructive Quantum Entangling Gate with Single-Photon Sources.

Heralded entangling quantum gates are an essential element for the implementation of large-scale optical quantum computation. Yet, the experimental demonstration of genuine heralded entangling gates with free-flying output photons in linear optical system, was hindered by the intrinsically probabilistic source and double-pair emission in parametric down-conversion. Here, by using an on-demand single-photon source based on a semiconductor quantum dot embedded in a micropillar cavity, we demonstrate a heralded controlled-NOT (CNOT) operation between two single photons for the first time. To characterize the performance of the CNOT gate, we estimate its average quantum gate fidelity of (87.8±1.2)%. As an application, we generated event-ready Bell states with a fidelity of (83.4±2.4)%. Our results are an important step towards the development of photon-photon quantum logic gates.

Glycine-Functionalized CsPbBr3 Nanocrystals for Efficient Visible-Light Photocatalysis of CO2 Reduction.

Capping ligands are indispensable for the preparation of metal-halide-perovskite (MHP) nanocrystals (NCs) with good stability; however, the long alkyl-chain capping ligands in conventional MHP NCs will be unfavorable for CO2 adsorption and hinder the efficient carrier separation on the surface of MHP NCs, leading to inferior catalytic activity in artificial photosynthesis. Herein, CsPbBr3 nanocrystals with short-chain glycine as ligand are constructed through a facile ligand-exchange strategy. Owing to the reduced hindrance of glycine and the presence of the amine group in glycine, the photogenerated carrier separation and CO2 uptake capacity are noticeably improved without compromising the stability of the MHP NCs. The CsPbBr3 nanocrystals with glycine ligands exhibit a significantly increased yield of 27.7 µmol g-1 h-1 for photocatalytic CO2 -to-CO conversion without any organic sacrificial reagents, which is over five times higher than that of control CsPbBr3 NCs with conventional long alkyl-chain capping ligands.

Overexpression of GmAAP6a enhances tolerance to low nitrogen and improves seed nitrogen status by optimizing amino acid partitioning in soybean.

Amino acid transport via phloem is one of the major source-to-sink nitrogen translocation pathways in most plant species. Amino acid permeases (AAPs) play essential roles in amino acid transport between plant cells and subsequent phloem or seed loading. In this study, a soybean AAP gene, annotated as GmAAP6a, was cloned and demonstrated to be significantly induced by nitrogen starvation. Histochemical staining of GmAAP6a:GmAAP6a-GUS transgenic soybean revealed that GmAAP6a is predominantly expressed in phloem and xylem parenchyma cells. Growth and transport studies using toxic amino acid analogs or single amino acids as a sole nitrogen source suggest that GmAAP6a can selectively absorb and transport neutral and acidic amino acids. Overexpression of GmAAP6a in Arabidopsis and soybean resulted in elevated tolerance to nitrogen limitation. Furthermore, the source-to-sink transfer of amino acids in the transgenic soybean was markedly improved under low nitrogen conditions. At the vegetative stage, GmAAP6a-overexpressing soybean showed significantly increased nitrogen export from source cotyledons and simultaneously enhanced nitrogen import into sink primary leaves. At the reproductive stage, nitrogen import into seeds was greatly enhanced under both sufficient and limited nitrogen conditions. Collectively, our results imply that overexpression of GmAAP6a enhances nitrogen stress tolerance and source-to-sink transport and improves seed quality in soybean. Co-expression of GmAAP6a with genes specialized in source nitrogen recycling and seed loading may represent an interesting application potential in breeding.

Observation of Intensity Squeezing in Resonance Fluorescence from a Solid-State Device.

Intensity squeezing-i.e., photon number fluctuations below the shot-noise limit-is a fundamental aspect of quantum optics and has wide applications in quantum metrology. It was predicted in 1979 that intensity squeezing could be observed in resonance fluorescence from a two-level quantum system. However, its experimental observation in solid states was hindered by inefficiencies in generating, collecting, and detecting resonance fluorescence. Here, we report the intensity squeezing in a single-mode fiber-coupled resonance fluorescence single-photon source based on a quantum dot-micropillar system. We detect pulsed single-photon streams with 22.6% system efficiency, which show sub-shot-noise intensity fluctuation with an intensity squeezing of 0.59 dB. We estimate a corrected squeezing of 3.29 dB at the first lens. The observed intensity squeezing provides the last piece of the fundamental picture of resonance fluorescence, which can be used as a new standard for optical radiation and in scalable quantum metrology with indistinguishable single photons.

IGF2-AS affects the prognosis and metastasis of gastric adenocarcinoma via acting as a ceRNA of miR-503 to regulate SHOX2.

Disorder of long non-coding RNAs (LncRNAs) is found in various types of cancers and demonstrated to be associated with tumor occurrence and development. Our study found that lncRNA insulin growth factor 2 antisense (IGF2-AS) is up-regulated in gastric adenocarcinoma (GAC) tissues and correlated with poor prognosis in patients with GAC. Cell counting kit-8 (CCK8), colony formation, wound healing and transwell assays revealed that knockdown of IGF2-AS in BGC823 and SGC7901 cells significantly suppressed cell proliferation, migration and invasion. While, overexpression of IGF2-AS in AGS and MGC803 cells exhibited the opposite effects. RNA-FISH and subcellular fractionation assay found that most IGF2-AS was distributed in the cytoplasm, suggesting that IGF2-AS functioned as a potential ceRNA. RNA binding protein immunoprecipitation (RIP) assays further confirmed this assumption. By informatics prediction and luciferase reporter assay, we found that IGF2-AS functioned as an efficient miR-503 sponge and the level of miR-503 showed an inverse correlation with IGF2-AS. Short stature homeobox 2 (SHOX2) is predicted and verified as a target of miR-503. Moreover, IGF2-AS expression exhibited a negative correlation with miR-503 and a positive correlation with IGF2-AS. Subsequent rescue assay revealed that down-regulation of miR-503 or restoration of SHOX2 canceled IGF2-AS depletion-induced depression in proliferation and motility of BGC823 and SGC7901 cells. Meanwhile, up-regulation of miR-503 or down-regulation of SHOX2 decreased IGF2-AS overexpression induced promotion in proliferation and motility of AGS and MGC803 cells. In vivo tumorigenicity assay showed that knockdown of IGF2-AS significantly reduced tumor volume. Taken together, our results demonstrated that IGF2-AS takes important regulatory parts in GAC development by functioning as a ceRNA to regulate SHOX2 via sponging miR-503.

Risk factors for delayed hemorrhage after endoscopic sphincterotomy.

BACKGROUND: Hemorrhage is one of the most serious complications of endoscopic sphincterotomy (EST). The risk factors for delayed hemorrhage are not clear. This study aimed to explore the risk factors for post-EST delayed hemorrhage and suggest some precautionary measures. METHODS: This study analyzed 8477 patients who successfully underwent endoscopic retrograde cholangiopancreatography (ERCP) and EST between January 2007 and June 2015 in the First Affiliated Hospital of Nanchang University. Univariate and multivariate analyses were performed to find the risk factors for delayed hemorrhage after EST. RESULTS: Of the 8477 patients screened, 137 (1.62%) experienced delayed hemorrhage. Univariate analysis showed that male, the severity of jaundice, duodenal papillary adenoma and carcinoma, diabetes, intraoperative bleeding, moderate and large incisions, and directional deviation of incision were risk factors for post-EST delayed hemorrhage (P < 0.05). Multivariate analysis showed that intraoperative bleeding [odds ratio (OR) = 3.326; 95% CI: 1.785-6.196; P < 0.001] and directional deviation of incision (OR = 2.184; 95% CI: 1.266-3.767; P = 0.005) were independent risk factors for post-EST delayed hemorrhage. CONCLUSIONS: Delayed hemorrhage is the most common and dangerous complication of EST. Intraoperative bleeding and directional deviation of incision are independent risk factors for post-EST delayed hemorrhage.

[Application value of whole exome sequencing in critically ill neonates with inherited diseases].

OBJECTIVE: To study the application value of whole exome sequencing (WES) in critically ill neonates with inherited diseases. METHODS: A total of 66 critically ill neonates with suspected inherited diseases or unclear clinical diagnosis who were admitted to the neonatal intensive care unit were enrolled as subjects. The clinical data of the neonates were collected, and venous blood samples were collected from the neonates and their parents for WES. The clinical manifestations of the neonates were observed to search for related pathogenic gene mutations. RESULTS: Among the 66 critically ill neonates with suspected inherited diseases or unclear clinical diagnosis (34 boys and 32 girls), 14 (21%) were found to have gene mutations by WES. One neonate had no gene mutation detected by WES but was highly suspected of pigment incontinence based on clinical manifestations, and multiplex ligation-dependent probe amplification detected a heterozygous deletion mutation in exons 4-10 of the IKBKG gene. Among the 15 neonates with gene mutations, 10 (67%) had pathogenic gene mutation, 1 (7%) was suspected of pathogenic gene mutation, and 4 (27%) had gene mutations with unknown significance. Among the 15 neonates, 13 underwent chromosome examination, and only 1 neonate was found to have chromosome abnormality. CONCLUSIONS: Chromosome examination cannot be used as a diagnostic method for inherited diseases, and WES detection technology is an important tool to find inherited diseases in critically ill neonates with suspected inherited diseases or unclear clinical diagnosis; however WES technology has some limitation and it is thus necessary to combine with other sequencing methods to achieve an early diagnosis.

Boson Sampling with 20 Input Photons and a 60-Mode Interferometer in a 10

Quantum computing experiments are moving into a new realm of increasing size and complexity, with the short-term goal of demonstrating an advantage over classical computers. Boson sampling is a promising platform for such a goal; however, the number of detected single photons is up to five so far, limiting these small-scale implementations to a proof-of-principle stage. Here, we develop solid-state sources of highly efficient, pure, and indistinguishable single photons and 3D integration of ultralow-loss optical circuits. We perform experiments with 20 pure single photons fed into a 60-mode interferometer. In the output, we detect up to 14 photons and sample over Hilbert spaces with a size up to 3.7×10^{14}, over 10 orders of magnitude larger than all previous experiments, which for the first time enters into a genuine sampling regime where it becomes impossible to exhaust all possible output combinations. The results are validated against distinguishable samplers and uniform samplers with a confidence level of 99.9%.

Epoxide-Mediated Stevens Rearrangements of α-Amino-Acid-Derived Tertiary Allylic, Propargylic, and Benzylic Amines: Convenient Access to Polysubstituted Morpholin-2-ones.

A new strategy has been established for the synthesis of polysubstituted morpholin-2-ones through Stevens rearrangements of tertiary amines via in situ activation with epoxides. A range of α-amino acid-derived tertiary allylic, propargylic, and benzylic amines reacted with epoxides in the presence of zinc halide catalysts to afford structurally diverse allyl-, allenyl-, and benzyl-substituted morpholin-2-ones, respectively, in moderate-to-good yields with high regioselectivity. The process involves [2,3]- and [1,2]-Stevens rearrangements of quaternary ammonium ylide intermediates and constitutes a very convenient method to prepare polysubstituted morpholin-2-ones through tandem formation of C-N, C-O, and C-C bonds. Moreover, replacing epoxides with aziridines permitted the synthesis of polysubstituted piperazin-2-ones.

Are paediatric clinical practice guidelines trustworthy?

AIM: To assess the methodological and reporting quality of paediatric clinical practice guidelines (CPGs) in National Guideline Clearinghouse (NGC) using the Appraisal of Guidelines for Research and Evaluation (AGREE) II instrument and Reporting Items for Practice Guidelines in Healthcare (RIGHT) standard. METHODS: We identified all published CPGs through the NGC, and search records were screened in duplicate for inclusion. Two researchers evaluated the methodological and reporting quality of paediatric CPGs using the AGREE II instrument and RIGHT standard. STATA version 12.0 and SPSS version 22.0 software were used to analyse the related data. RESULTS: A total of 50 paediatric CPGs were included. The scores for all six domains by AGREE II instrument were presented as follows: scope and purpose (85.6 ± 9.59), stakeholder involvement (69.15 ± 19.32), rigour of development (73.19 ± 17.18), clarity of presentation (78.51 ± 14.36), applicability (54.61 ± 22.63) and editorial independence (68.42 ± 13.06). In the seven domains of the RIGHT standard, the reporting rate of the recommendation domain was the lowest (52.86%).The highest reporting rate was the other information domain, which was 68%.There was a high correlation between reporting the completeness of CPGs using the AGREE II instrument and RIGHT standard (r = 0.77, P < 0.001). CONCLUSIONS: The paediatric CPGs from NGC have good quality. There was a high correlation in the completeness of reporting for paediatric CPGs using the AGREE II instrument and RIGHT standard. It could be concluded that the CPGs of good methodological quality have good reporting quality. Maybe the researcher should effectively combine the AGREE II instrument and RIGHT standard in the development process of CPGs.

The Analysis of the Urea Biosensors Using Different Sensing Matrices via Wireless Measurement System & Microfluidic Measurement System.

Two types of urea biosensors were integrated with a wireless measurement system and microfluidic measurement system. The two biosensors used were (i) a magnetic beads (MBs)-urease/graphene oxide (GO)/titanium dioxide (TiO2)-based biosensor and (ii) an MBs-urease/GO/ nickel oxide (NiO)-based biosensor, respectively. The wireless measurement system work exhibited the feasibility for the remote detection of urea, but it will require refinement and modification to improve stability and precision. The microchannel fluidic system showed the measurement reliability. The sensing properties of urea biosensors at different flow rates were investigated. From the measurement results, the decay of average sensitivity may be attributed to the induced vortex-induced vibrations (VIV) at the high flow rate. In the aspect of wireless monitoring, the average sensitivity of the urea biosensor based on MBs-urease/GO/NiO was 4.780 mV/(mg/dl) and with the linearity of 0.938. In the aspect of measurement under dynamic conditions, the average sensitivity of the urea biosensor based on MBs-urease/GO/NiO were 5.582 mV/(mg/dl) and with the linearity of 0.959. Both measurements performed NiO was better than TiO2 according to the comparisons.

[Visual analysis of research theme and capability of real world research].

As a new concept in clinical research,the real world research(RWR) has attracted the attention of researchers in the world with its unique advantages. This research mainly analyzed it through visual methods,the specific steps were as follows. Firstly,the Chinese Biomedical Literature Database,China National Knowledge Infrastructure,Wan Fang Database,Medline and EMbase were searched and RWS were included,414 articles in Chinese and 2 158 articles in English were included in this research after layer-bylayer screening; secondly,the main information was extracted and sorted by BICOMS 2 software and generated its co-occurrence matrix; the network relationship diagram was drawn by Net Draw software; the cluster analysis was carried out by using g CLUTO software;finally,this research results show that the numbers of domestic and foreign literatures have shown an overall growth trend,but compared with foreign countries,China's research on the real world started late,the overall strength of research was not as good as abroad;and the domestic and foreign research on the real world was uneven in the region,the research in China was mainly distributed in developed provinces and cities,such as Beijing,Guangdong,Shanghai,etc,and there was a lack of close cooperation between provinces and cities; the foreign research are mainly distributed in developed countries such as the United States,the United Kingdom,Germany,et al; the cooperation between countries was relatively close. And the hotspots and core directions of domestic and foreign research were also different. This research was intended to provide reference for the further research of Chinese researchers through the current description of the themes and capability of the real world research in the world.

Rapid and sensitive detection of the phenoxy acid herbicides in environmental water samples by magnetic solid-phase extraction combined with liquid chromatography-tandem mass spectrometry.

Phenoxy acid herbicides are widely used herbicides that play an important role in improving the yield and quality of crops. However, some research has shown that this kind of herbicide is poisonous to human and animals. In this study, a rapid and sensitive method was developed for the detection of seven phenoxy acid herbicides in water samples based on magnetic solid-phase extraction followed by liquid chromatography and tandem mass spectrometry. Magnetic amino-functionalized multiwalled carbon nanotubes were prepared by mixing bare magnetic Fe3 O4 nanoparticles with commercial amino-functionalized multiwalled carbon nanotubes in water. Then the amino-functionalized multiwalled carbon nanotubes were used to enrich phenoxy acid herbicides from water samples based on hydrophobic and ionic interactions. The effects of experimental variables on the extraction efficiency have been studied in detail. Under the optimized conditions, the method validation was performed. Good linearities for seven phenoxy acid herbicides were obtained with squared regression coefficients ranging from 0.9971 to 0.9989. The limits of detection ranged from 0.01 to 0.02 µg/L. The method recoveries of seven phenoxy acid herbicides spiked at three concentration levels in a blank sample were from 92.3 to 103.2%, with inter- and intraday relative standard deviations less than 12.6%.

[Preparation process of norcantharidin/tetrandrine dual loaded liposomes and their in vitro release characteristics].

In order to optimize the prescription and preparation process of norcantharidin/tetrandrine dual loaded liposomes, the dual drug loaded liposomes were prepared by film dispersion-ultrasonic method using norcantharidin-mesoporous silica nanoparticles（MSN-NCTD）and tetrandrine（Tet）. With particle size and encapsulation efficiency as comprehensive indexes, the influences of phospholipid cholesterol amount, ultrasonic time and ultrasonic power on prescription process were investigated by orthogonal test; the in vitro release characteristics of liposomes were investigated by dialysis method. The results indicated that the best prescription process of prepared norcantharidin/tetrandrine dual loaded liposomes was as follows: phospholipid-cholesterol ratio 2.5:1, ultrasonic time 4 min, ultrasonic power 40%; the encapsulation efficiency was 86.62% and 79.19%respectively for NCTD and Tet;liposomes were well-shaped under the transmission microscope, with average particle size of （207.5±3.6） nm, Zeta potential of （1.345±0.173） mV; and the 48 h cumulative release rates of NCTD and Tet were 85.14% and 85.00% respectively. The experiment results proved that the dual drug loaded liposomes prepared by film dispersion-ultrasonic method had uniform particle size, high encapsulation efficiency and in vitro sustained release characteristics.