A model for continuous sample feed and separation with counter-current chromatography based on elution-extrusion mode and its application.

A novel and meaningful theoretical model was established with counter-current chromatography based on the elution-extrusion mode for efficient continuous separation. For the experimental verification of the theory, the separation of the binary mixture luteolin/baicalein was studied. The velocity model and volume model of the chromatographic separation behavior of the target compounds in the separation process were given by theoretical analysis. The results showed that this method had obvious advantages in the separation of binary mixtures. In addition, the established model was used to predict and isolate oleuropein from olive leaves. A two-phase solvent system of n-butanol/ethyl acetate/methanol/water (1:19:1:19, v/v/v/v) was chosen for the continuous separation of oleuropein. After optimizing the conditions in this way, a large amount of sample loading was achieved; the volume of injections can reach 48 ml, approximately 35.29% of the volume of the counter-current chromatography column, and oleuropein with a purity of 86.42% was obtained within 80 min. The model provided technical support for the prediction of chromatographic behavior and operating parameters during continuous separation and preparation of counter-current chromatography. It has great application prospects and significance in separation preparation, especially in large-scale industrial preparation.

Recovery and recycling of solvent of counter-current chromatography: The sample of isolation of zeaxanthin in the Lycium barbarum L. fruits.

An efficient method of recovering and recycling solvent for counter-current chromatography was established by which zeaxanthin was separated from Lycium barbarum L. fruits. A column with activated carbon combined with high performance counter-current chromatography formed the recovering and recycling solvent system. Using the solvent system of n-hexane-ethyl acetate-ethanol-water (8:2:7:3, v/v) from the references, five injections were performed with an almost unchanged purity of zeaxanthin (80.9, 81.2, 81.5, 81.3, and 80.2% respectively) in counter-current chromatography separation. Meanwhile, the mobile phase reduced by half than conventional counter-current chromatography. By this present method, an effective improvement of counter-current chromatography solvent utilization was achieved.

Full use of the liquid nature of the stationary phase: The development of elution-extrusion counter current chromatography.

Elution-extrusion counter current chromatography extrudes the most solute retained in the column with the highest possible peak resolution. It can greatly improve the hydrophobic window. In recent years, elution-extrusion counter current chromatography has received extensive attention in the separation of complex samples. This article first reviews the development and application of elution-extrusion counter current chromatography, including its origin, mechanism, advantages and disadvantages, and some representative applications. At the same time, this review also shared our visions and ideas on how to improve the elution-extrusion mode. This article aims to provide certain reference for the research of this technology.

Effective on-line high-speed shear dispersing emulsifier technique coupled with high-performance countercurrent chromatography method for simultaneous extraction and isolation of carotenoids from Lycium barbarum L. fruits.

An efficient combination strategy based on high-speed shear dispersing emulsifier technique and high-performance countercurrent chromatography was developed for on-line extraction and isolation of carotenoids from the fruits of Lycium barbarum. In this work, the high-speed shear dispersing emulsifier technique has been employed to extract crude extracts using the upper phase of high-performance countercurrent chromatography solvent system composed of n-hexane-dichloromethane-acetonitrile (10:4:6.5, v/v) as the extraction solvent. At the separation stage, the high-performance counter-current chromatography process adopts elution-extrusion mode and the upper phase of the solvent system as stationary phase (reverse-phase mode). As a result, three compounds including zeaxanthin, zeaxanthin monopalmitate, and zeaxanthin dipalmitate with purities of 89, 90, and 93% were successfully obtained in one extraction-separation operation within 120 min. The targeted compounds were analyzed and identified by high-performance liquid chromatography, mass spectrometry, and NMR spectroscopy. The results indicated that the present on-line combination method could serve as a simple, rapid, and effective way to achieve weak polar and unstable compounds from natural products.

Continuous separation of maslinic and oleanolic acids from olive pulp by high-speed countercurrent chromatography with elution-extrusion mode.

In this work, a continuous high-speed countercurrent chromatography method has been developed on the basis of elution-extrusion mode and this method was successfully applied to the separation of maslinic and oleanolic acid from the extract of olive pulp. In the process of 'elution', the sample solution was continuously loaded into the column and the maslinic acid was steadily eluted out in this step while highly retained oleanlic acid always stayed in the column. In the process of 'extrusion', the oleanlic acid was pushed out of the column with the stationary phase. In this way, we achieved a large sample loading. A total of 120 mL sample solution (about 89.55% of the column volume) which contains 600 mg olive pulp extract was pumped in the apparatus by a constant-flow pump and the maslinic and oleanolic acids were largely separated within 120 min. Both of these two compounds presented high yields and high purities (271.6 mg for maslinic acid with 86.7% and 83.9 mg oleanolic acids with 83.4%).

Synthesis and biological evaluation of 4ß-(thiazol-2-yl)amino-4'-O-demethyl-4-deoxypodophyllotoxins as topoisomerase-II inhibitors.

A series of 4ß-(thiazol-2-yl)amino-4'-O-demethyl-4-deoxypodophyllotoxins were synthesized, and their cytotoxicities were evaluated against four human cancer cell lines (A549, HepG2, HeLa, and LOVO cells) and normal human diploid fibroblast line WI-38. Some of the compounds exhibited promising antitumor activity and less toxicity than the anticancer drug etoposide. Among them, compounds 15 and 17 were found to be the most potent synthetic derivatives as topo-II inhibitors, and induced DNA double-strand breaks via the p73/ATM pathway as well as the H2AX phosphorylation in A549 cells. These compounds also arrested A549 cells cycle in G2/M phase by regulating cyclinB1/cdc2(p34). Taken together, these results show that a series of compounds are potential anticancer agents.

The development of biphasic chiral recognition in chiral separation.

In chiral separation, enantioseparation factor is an important parameter which influences the resolution of enantiomers. In this current overview, a biphasic chiral recognition method is introduced to the readers. This method can significantly improve the enantioseparation factor in two-phase solvent through adding lipophilic and hydrophilic chiral selectors which have opposite chiral recognition ability to organic and aqueous phases, respectively. This overview presents the development and applications of biphasic chiral recognition in liquid-liquid extraction and counter current chromatography. It mainly focuses on the topics of mechanism, advantages and limitations, applications, and key factors of biphasic chiral recognition. In addition, the future outlook on development of biphasic chiral recognition also has been discussed in this overview.

Development of overlapping repeated separation of steviol glycosides with counter current chromatography and a comparison with a conventional repeated separation method.

Repeated separation is a valuable method in counter current chromatography, especially on a preparative scale. It can greatly reduce the separation time and the consumption of solvent. In this study, an overlapping repeated separation method was developed. Meanwhile, this method was used to separate steviol glycosides and compared with conventional repeated separation method. The results show that both methods are effective ways for countercurrent chromatography to prepare compounds but the overlapping repeated separation method requires fewer time and solvent than the conventional repeated separation method. So this novel repeated separation method has enormous potential for a preparative separation of target compounds and is very useful for the high-throughput purification of natural products.

[Research progress on biological activities of Olea europaea leaf extract].

Olea europaea oil is one of the most important part of the "Mediterranean dietary pattern", and a lot of epidemiological evidences showed that people with the Mediterranean diet having a lower morbidity of the cardiovascular system diseases, skin cancer and colon cancer. The health benefits of a Mediterranean diet not only attributed to monounsaturated fatty acids and vitamins and other nutrients in O. europaea oil, but also the phenolic compounds named as antioxidant effect. Studies have shown that O. europaea leaf contains much more antioxidant activity composition than the fruit, and oleuropein, flavonoids such polyphenols are the main active ingredients in O. europaea leaf. A small amount of O. europaea was introduced into China in 1956, after widely cultivated in Fujian, Guangdong, Taiwan, Sichuan, Shaanxi, Yunnan, and Longnan in Gansu province is the biggest O. europaea planting area in the country. In every winter pruning O. europaea will produce a large number of the leaves, which could be a high added value products (phenolic compounds) of rich source. This article through consulting the literature at home and abroad, classified and summarized the biological activity research status of O. europaea leaf extract and the possible mechanisms, including antimicrobial, antitumor, antioxidation, and on the function of brain, cardiovascular system, anti-diabetes, anti-inflammatory and analgesia and so on. At the same time looked ahead to its development prospects of O. europaea leaf extract, it has variety and high content of active ingredients, and antioxidant synergy, which provide a theoretical basis for the further development and utilization of O. europaea leaf. And O. europaea leaf extract has a rich cheap source and good bioavailability, which provided a broad space in the application of medical and health care.

Picotesla-sensitivity microcavity optomechanical magnetometry.

Cavity optomechanical systems have enabled precision sensing of magnetic fields, by leveraging the optical resonance-enhanced readout and mechanical resonance-enhanced response. Previous studies have successfully achieved mass-produced and reproducible microcavity optomechanical magnetometry (MCOM) by incorporating Terfenol-D thin films into high-quality (Q) factor whispering gallery mode (WGM) microcavities. However, the sensitivity was limited to 585 pT Hz-1/2, over 20 times inferior to those using Terfenol-D particles. In this work, we propose and demonstrate a high-sensitivity and mass-produced MCOM approach by sputtering a FeGaB thin film onto a high-Q SiO2 WGM microdisk. Theoretical studies are conducted to explore the magnetic actuation constant and noise-limited sensitivity by varying the parameters of the FeGaB film and SiO2 microdisk. Multiple magnetometers with different radii are fabricated and characterized. By utilizing a microdisk with a radius of 355 µm and a thickness of 1 µm, along with a FeGaB film with a radius of 330 µm and a thickness of 1.3 µm, we have achieved a remarkable peak sensitivity of 1.68 pT Hz-1/2 at 9.52 MHz. This represents a significant improvement of over two orders of magnitude compared with previous studies employing sputtered Terfenol-D film. Notably, the magnetometer operates without a bias magnetic field, thanks to the remarkable soft magnetic properties of the FeGaB film. Furthermore, as a proof of concept, we have demonstrated the real-time measurement of a pulsed magnetic field simulating the corona current in a high-voltage transmission line using our developed magnetometer. These high-sensitivity magnetometers hold great potential for various applications, such as magnetic induction tomography and corona current monitoring.

DPMA, a deoxypodophyllotoxin derivative, induces apoptosis and anti-angiogenesis in non-small cell lung cancer A549 cells.

We found that the deoxypodophyllotoxin derivative, 2,6-dimethoxy-4-(6-oxo-(5R,5aR,6,8,8aR,9-hexahydrofuro[3',4':6,7]naphtho[2,3-d][1,3]dioxol-5-yl)phenyl ((R)-1-amino-4-(methylthio)-1-oxobutan-2-yl)carbamate (DPMA), exhibited superior cytotoxicity compared with etoposide. In this study, we investigated the mechanism of action of DPMA. DPMA exhibited anti-proliferative activity and induced apoptosis in A549 cells in a dose- and time-dependant manner. DPMA inhibited microtubule formation and induced expression of Bax, cleaved caspase-3, p53 and ROS, and inhibited Bcl-2 expression. DPMA also affected cyclinB1, cdc2 and p-cdc2 expression, inducing cell cycle arrest. DPMA also inhibited tube formation of VEGF-induced human umbilical vein endothelial cells. These studies demonstrate that DPMA inhibits p53/cdc2/Bax signaling, thereby inhibiting cell growth/angiogenesis and inducing apoptosis.

Synthesis and evaluation of the cell cycle arrest and CT DNA interaction properties of 4ß-amino-4'-O-demethyl-4-deoxypodophyllotoxins.

A series of 4ß-amino-4'-O-demethyl-4-deoxypodophyllotoxin derivatives were synthesized, and their cytotoxicities against several human cancer cell lines, including HepG2, A549, HeLa and HCT-8 cells, evaluated. Some of these compounds exhibited higher levels of cytotoxicity than the anticancer drug etoposide. 4ß-N-(4-Nitrophenyl piperazinyl)-4'-O-demethyl-4-deoxypodophyllotoxin (11) was found to be the most potent synthesized compound in the current study, and induced cell cycle arrest in the G2/M phase in HeLa cells, which was accompanied by apoptosis. Furthermore, this compound activated the expression of cdc2, cyclin B1, p53 and caspase-3 in HeLa cells, leading to changes in the conformation of calf thymus DNA from the B-form to a more compact C-form.

Resveratrol Prevents Vibrio vulnificus-Induced Sepsis by Attenuating Necroptosis.

Objective: This study investigated how the natural phytophenol and potent SIRT1 activator resveratrol (RSV) regulate necroptosis during Vibrio vulnificus (V. vulnificus)-induced sepsis and the potential mechanism. Methods: The effect of RSV on V. vulnificus cytolysin (VVC)-induced necroptosis was analyzed in vitro using CCK-8 and Western blot assays. Enzyme-linked immunosorbent assays and quantitative real-time polymerase chain reaction, western blot, and immunohistochemistry and survival analyses were performed to elucidate the effect and mechanism of RSV on necroptosis in a V. vulnificus-induced sepsis mouse model. Results: RSV relieved necroptosis induced by VVC in RAW264.7 and MLE12 cells. RSV also inhibited the inflammatory response, had a protective effect on histopathological changes, and reduced the expression level of the necroptosis indicator pMLKL in peritoneal macrophages, lung, spleen, and liver tissues of V. vulnificus-induced septic mice in vivo. Pretreatment with RSV downregulated the mRNA of the necroptosis indicator and protein expression in peritoneal macrophages and tissues of V. vulnificus-induced septic mice. RSV also improved the survival of V. vulnificus-induced septic mice. Conclusion: Our findings collectively demonstrate that RSV prevented V. vulnificus-induced sepsis by attenuating necroptosis, highlighting its potency in the clinical management of V. vulnificus-induced sepsis.

Larger deep white matter hyperintensity volume correlates with more severe social behavioral changes in patients with subacute ischemic stroke.

Background: Changes in social behavior can occur after ischemic stroke. We aimed to investigate the potential correlations between neuroimaging variables and changes in social behavior in patients who experienced subacute ischemic stroke. Methods: We prospectively screened patients with first-ever ischemic stroke. Three months after the index stroke, changes in patients' social behavior were investigated by the Frontal Behavioral Inventory (FBI), which consists of both deficit and positive groups of behaviors. The protocol of brain magnetic resonance imaging (MRI) including the baseline MRI at the acute stage and additional MRI with three-dimensional T1-weighted imaging on follow-up. Using these MRI scans, we assessed the acute infarction and the volumes of various brain structures by an automatic volumetry tool. Results: Eighty patients were enrolled. In univariate analyses, patients with deficit behavioral changes had more left cortical infarction (r = 0.271, p = 0.015), Cholinergic Pathways Hyperintensities Scale scores (r = 0.227, p = 0.042), DWMH volumes (r = 0.349, p = 0.001), and modified Rankin Scale (mRS) scores (r = 0.392, p < 0.001). Patients with positive behavioral changes had more frequency of men (r = 0.229, p = 0.041) and a history of hypertension (r = 0.245, p = 0.028). In multiple stepwise linear regression models, after adjusting for age, deep WMH volumes (ß = 0.849, 95% confidence interval = 0.352-1.346, p = 0.001) and mRS scores on follow-up (ß = 1.821, 95% confidence interval = 0.881-2.76, p < 0.001) were significantly correlated with deficit behavioral changes (R2 = 0.245). Conclusion: Larger deep WMH volumes and poorer mRS scores on follow-up were significantly correlated with deficit behavioral changes in patients with subacute ischemic stroke.

Right Cortical Infarction and a Reduction in Putamen Volume May Be Correlated with Empathy in Patients after Subacute Ischemic Stroke-A Multimodal Magnetic Resonance Imaging Study.

Empathy has not been well studied in patients following ischemic stroke. We aimed to evaluate the relationships of multimodal neuroimaging parameters with the impairment of empathy in patients who had experienced subacute ischemic stroke. Patients who had experienced a first-event acute ischemic stroke were recruited, and we assessed their empathy using the Chinese version of the Empathy Quotient (EQ) 3 months after the index stroke. Multimodal magnetic resonance imaging (MRI) was conducted in all the participants to identify acute infarction and assess brain volumes, white matter integrity, and other preexisting abnormalities. We quantified the brain volumes of various subcortical structures, the ventricles, and cortical lobar atrophy. The microstructural integrity of the white matter was reflected in the mean fractional anisotropy (FA) and mean diffusivity (MD), and the regional mean values of FA and MD were quantified after mapping using the ICBM_DTI_81 Atlas. Twenty-three (56.1%) men and 18 (43.9%) women (mean age: 61.73 years, range: 41-77 years) were included. The median National Institutes of Health Stroke Scale (NIHSS) score at discharge was 1 (range: 0-4). On univariate analysis, the EQ was correlated with right cortical infarction (r = -0.39, p = 0.012), putamen volume (r = 0.382, p = 0.014), right putamen volume (r = 0.338, p = 0.031), and the FA value of the right sagittal stratum. EQ did not correlated with the MD value in any region of interest or pre-existing brain abnormalities. Multiple stepwise linear regression models were used to identify factors associated with EQ. After adjusting for age and the NIHSS score on admission, the frequency of right cortical infarcts negatively correlated with EQ (standardized ß = -0.358, 95% confidence interval =-0.708 to -0.076, p = 0.016), and the putamen volume positively correlated with EQ (standardized ß = 0.328, 95% confidence interval =0.044 to 0.676, p = 0.027). In conclusion, in patients who have experienced subacute ischemic stroke, right cortical infarction and a smaller putamen volume are associated with the impairment of empathy.

Development of an effective method based upon second-order overlapping repeated sample injections for isolation of carotenoids from Lycium barbarum L. fruits with elution-extrusion counter-current chromatography.

Carotenoids are one of the main active components in Lycium barbarum L. fruit, which has a wide range of excellent biological activities. In this study, a novel second-order overlapping repeated injection method with elution-extrusion counter-current chromatography was developed for isolation and preparation of carotenoids from L. barbarum fruits. And three carotenoids were successfully separated using the solvent system composed of n-hexane/dichloromethane/acetonitrile (10:3.5:6.5, v/v) with the injection before equilibrium method. The entire separation process consisted of three complete elution-extrusion cycles with a total of 9 injections (80 mg crude extract per injection). Finally, three target compounds including zeaxanthin (28.5 mg), zeaxanthin monopalmitate (45.8 mg), and zeaxanthin dipalmitate (161.5 mg) with average purities of 87.9%, 88.9%, and 91.2% were successfully obtained in one complete second-order overlapping repeated elution-extrusion CCC process within 651 min. The result indicated that this second-order overlapping repeated method is efficient for large-scale preparation of carotenoids based on its advantages of large amount of sample injection and low solvent consumption. So this novel second-order overlapping repeated elution-extrusion counter-current chromatography separation method has enormous potential for largely preparative separation of natural bioactive compounds, such as carotenoids, which have good biological activity but possess unstable or other special chemical structure. It is worth noting that this overlapping repeated injections method requires target compounds to meet the requirements of elution-extrusion counter-current chromatography, and the normal implementation of this method is closely related to the sufficient interval of elution time between the target compounds.

[Toxic effects of sublethal acetochlor with sublethal doses on earthworms in soil using multi-endpoints system]. / äºšè‡´æ­»å‰‚é‡ä¹™è‰èƒºå¯¹èš¯èš“çš„æ¯’æ€§æ•ˆåº”åŠæ•æ„Ÿç”Ÿç‰©æ ‡è®°ç‰©.

In this study, we examined the toxic effect of sublethal doses of acetochlor (1, 2, 4, 8 mg·kg-1) on earthworms by exogenous addition. The growth inhibition rate, cytochrome P450 isozymes (CYP1A2, 2C9 and 3A4) activities and the metabolomics were analyzed after seven days of exposure, to infer the toxicity threshold of acetochlor, screen the sensitive biomarkers from the levels of the individual, detoxified enzymes and small molecular metabolites, and elucidate the underlying toxicity mechanism. The results showed that CYP1A2, 2C9 and 3A4 activities were all significantly inhibited, and that the levels of ten metabolites (fructose-6-diphosphate, cytosine monophosphate, uridine monophosphate, adenosine monophosphate, adenosine, xanthine, fumaric acid, dihydroxyglutaric acid, ornithine and 16-hydroxyeicosatetraenoic acid) were significantly decreased by acetochlor exposure. The levels of six metabolites (adenosine succinic acid, succinic acid, arginine, tryptophan, asparagine and phenylalanine) were significantly increased when earthworms being exposed to 2-8 mg·kg-1 acetochlor. Acetochlor exposure caused oxidative damage to earthworms, weakened the glycolysis, disturbed the tricarboxylic acid cycle, disordered the purine and pyrimidine metabolism, and impaired the amino acids metabolism. Compared with the end point at individual level, the above 16 small molecule metabolites and CYP isozymes activities were more sensitive to acetochlor exposure. It was thus recommended that CYP isozymes (1A2, 2C9, and 3A4) activities and small molecular metabolites could be used as a set of biomarkers to diagnose the acetochlor pollution, given their high sensitivity and accuracy.

Beclin1 inhibition enhances paclitaxel­mediated cytotoxicity in breast cancer in vitro and in vivo.

Beclin1, a key regulator of autophagy, has been demonstrated to be associated with cancer cell resistance to chemotherapy. Paclitaxel is a conventional chemotherapeutic drug used in the clinical treatment of breast cancer. However, the function and mechanism of Beclin1 in paclitaxel­mediated cytotoxicity in breast cancer are not well defined. The present study demonstrated that paclitaxel suppressed cell viability and Beclin1 expression levels in BT­474 breast cancer cells in a dose­ and time­dependent fashion. Compared with the control, the knockdown of Beclin1 significantly enhanced breast cancer cell death via the induction of caspase­dependent apoptosis following paclitaxel treatment in vitro (P<0.05). In a BT­474 xenograft model, paclitaxel achieved substantial inhibition of tumor growth in the Beclin1 knockdown group compared with the control group. Furthermore, analysis of the publicly available Gene Expression Omnibus datasets revealed a clinical correlation between Beclin1 levels and the response to paclitaxel therapy in patients with breast cancer. Collectively, the present results suggest that Beclin1 protects breast cancer cells from apoptotic death. Thus, the inhibition of Beclin1 may be a novel way to improve the effect of paclitaxel. Additionally, Beclin1 may function as a favorable prognostic biomarker for paclitaxel treatment in patients with breast cancer.

A review on chiral separation by counter-current chromatography: Development, applications and future outlook.

Chiral separation has been a remarkably active area of research over the past long time and it still stays that way. Over the last few decades, counter-current chromatography (CCC) was successfully applied to the field of chiral separation. It provides an attractive approach to obtain pure enantiomer, particularly in preparative application because of its unique advantages of high load capacity, low solvent consumption and easy scale-up. The last several years great strides have been made in chiral separation by CCC, ranging from novel elution modes such as recycling elution mode and multiple dual mode elution to more specialized approaches such as pH-zone-refining and biphasic chiral recognition technologies. These developments have greatly improved the resolution of enantiomers and promoted the application of CCC in the field of chiral separation. Although not as popular as its application to the field of separation of natural product, the development of chiral separation by CCC should not be underrated. In this review article, we refer to the development, applications and future outlook of chiral separation by CCC, with emphasis on topics of its history, mechanism, advantages, limitations, current development and challenges. Meanwhile, its orientation of continued evolution and future outlook also have been discussed. While some scientific and technological problems have not yet been solved thoroughly, chiral separation by CCC has demonstrated potential advantages and prospects in this field and has good chance at preparative enantioseparation.

Management of Humeral Shaft Fractures With Intramedullary Interlocking Nail Versus Locking Compression Plate.

Surgical fixation of humeral shaft fractures generally involves plating or nailing. It is unclear whether one method is more effective than the other. The aim of this study was to compare the results of the intramedullary nail and locking compression plate for the treatment of humeral shaft fractures. A total of 60 patients with humeral shaft fractures were randomized to undergo surgery with an intramedullary interlocking nail (n=30) or locking compression plate (n=30). The outcome was assessed in terms of intraoperative blood loss, operative time, hospital stay, union time, union rate, functional outcome, and incidence of complications. Functional outcome was assessed using the Constant score and the American Shoulder and Elbow Surgeons (ASES) score. Intraoperative blood loss, operative time, and hospital stay in group A (intramedullary interlocking nail) were significantly lower than those in group B (locking compression plate). No statistically significant difference was found regarding the union rate, mean Constant score, and mean ASES score between the groups. The average union time was found to be significantly lower for the intramedullary interlocking nail compared with the locking compression plate. The incidence of complications such as radial nerve palsy was found to be higher with the locking compression plate compared with the intramedullary interlocking nail. The intramedullary interlocking nail can be considered a better surgical option for the management of humeral shaft fractures because it offers decreased intraoperative blood loss; shorter operative times, hospital stays, and union times; and a lower incidence of serious complications such as radial nerve palsy.