A simple approach to prepare a sulfone-embedded stationary phase for HPLC.

In the present study, a polar-embedded reversed-phase liquid chromatographic stationary phase that contained internal sulfone groups was prepared. The synthesis involved the "thiol-ene" click chemistry between the vinyl functionalized silica and 1-octadecanethiol, followed by the oxidization of sulfide to sulfone groups. The resulting material simultaneously possessed the alkyl chain, i.e. C18, and the internal sulfone groups. Elemental analysis demonstrates that the element contents of the C18/sulfone silica were C 8.94%, H 1.87% and S 0.66%. Chromatographic evaluations indicate that the C18/sulfone stationary phase exhibited a little less retention than the C18/sulfide one. A comparable chromatographic performance of neutral analytes was obtained on these two columns, but much better chromatographic performance in the case of basic and acid analytes was obtained on C18/sulfone stationary phase with additional features such as lower silanol activity, better stability (stable working conditions of pH 1.0-10.0), and better compatibility with 100% aqueous mobile phases. The batch-to-batch reproducibility was acceptable (the RSDs of retention times for the probes were no higher than 1.73%), demonstrating the suitability of the applied synthetic strategy for the new stationary phase. The C18/sulfone is a promising polar-embedded RPLC stationary phase.

Penetrable silica microspheres for immobilization of bovine serum albumin and their application to the study of the interaction between imatinib mesylate and protein by frontal affinity chromatography.

In the current study, novel featured silica, named penetrable silica, simultaneously containing macropores and mesopores, was immobilized with bovine serum albumin (BSA) via Schiff base method. The obtained BSA-SiO2 was employed as the high-performance liquid chromatographic (HPLC) stationary phase. Firstly, D- and L-tryptophan were used as probes to investigate the chiral separation ability of the BSA-SiO2 stationary phase. An excellent enantioseparation factor was obtained up to 4.3 with acceptable stability within at least 1 month. Next, the BSA-SiO2 stationary phase was applied to study the interaction between imatinib mesylate (IM) and BSA by frontal affinity chromatography. A single type of binding site was found for IM with the immobilized BSA, and the hydrogen-bonding and van der Waals interactions were expected to be contributing interactions based on the thermodynamic studies, and this was a spontaneous process. Compared to the traditional silica for HPLC stationary phase, the proposed penetrable silica microsphere possessed a larger capacity to bond more BSA, minimizing column overloading effects and enhancing enantioseparation ability. In addition, the lower running column back pressure and fast mass transfer were meaningful for the column stability and lifetime. It was a good substrate to immobilize biomolecules for fast chiral resolution and screening drug-protein interactions.

Novel mode of liquid-phase microextraction: A magnetic stirrer as the extractant phase holder.

In the present study, a novel configuration of liquid-phase microextraction was proposed, in which a magnetic stirrer with a groove was used as the extractant phase holder. It was termed as magnetic stirrer liquid-phase microextraction. In this way, the stability of the organic solvent was much improved under high stirring speed; the extraction efficiency was enhanced due to the enormously enlarged contact area between the organic solvent and aqueous phase. The extraction performance of the magnetic stirrer liquid-phase microextraction was studied using chlorobenzenes as the probe analytes. A wide linearity range (20 pg/mL to 200 ng/mL) with a satisfactory linearity coefficient (r(2) > 0.998) was obtained. Limits of detection ranged from 9.0 to 12.0 pg/mL. Good reproducibility was achieved with intra- and inter-day relative standard deviations <4.8%. The proposed magnetic stirrer liquid-phase microextraction was simple, environmentally friendly and efficient; compared to single-drop microextraction, it had obvious advantages in terms of reproducibility and extraction efficiency. It is a promising miniaturized liquid-phase technology for real applications.

Coupling carbon nanotube film microextraction with desorption corona beam ionization for rapid analysis of Sudan dyes (I-IV) and Rhodamine B in chilli oil.

A rapid analysis method by coupling carbon nanotube film (CNTF) microextraction with desorption corona beam ionization (DCBI) was developed for the determination of Sudan dyes (I-IV) and Rhodamine B in chilli oil samples. Typically, CNTF was immersed into the diluted solution of chilli oil for extraction, which was then placed directly under the visible plasma beam tip of the DCBI source for desorption and ionization. Under optimized conditions, five dyes were simultaneously determined using this method. Results showed that the analytes were enriched by the CNTF through the π-π interactions, and the proposed method could significantly improve the sensitivities of these compounds, compared to the direct analysis by DCBI-MS/MS. The method with a linear range of 0.08-12.8 µg g(-1) and good linear relationships (R(2) > 0.93) in a multiple reaction monitoring (MRM) mode was developed. Satisfactory reproducibility was achieved. Relative standard deviations (RSDs) were less than 20.0%. The recoveries ranged from 80.0 to 110.0%, and the limits of detection (LODs) were in the range of 1.4-21 ng g(-1). Finally, the feasibility of the method was further exhibited by the determination of five illegal dyes in chilli powder. These results demonstrate that the proposed method consumes less time and solvent than conventional HPLC-based methods and avoids the contamination of chromatographic column and ion source from non-volatile oil. With the help of a 72-well shaker, multiple samples could be treated simultaneously, which ensures high throughput for the entire pretreatment process. In conclusion, it provides a rapid and high-throughput approach for the determination of such illicit additions in chilli products.

A novel two-dimensional liquid-chromatography method for online prediction of the toxicity of transformation products of benzophenones after water chlorination.

Benzophenone-type UV filters (BPs) are ubiquitous in the environment. Transformation products (TPs) of BPs with suspected toxicity are likely to be produced during disinfection of water by chlorination. To quickly predict the toxicity of TPs, in this study, a novel two-dimensional liquid-chromatography (2D-LC) method was established in which the objective of the first dimension was to separate the multiple components of the BPs sample after chlorination, using a reversed-phase liquid-chromatography mode. A biochromatographic system, i.e. bio-partitioning micellar chromatography with the polyoxyethylene (23) lauryl ether aqueous solution as the mobile phase, served as the second dimension to predict the toxicity of the fraction from the first dimension on the basis of the quantitative retention-activity relationships (QRARs) model. Six BPs, namely 2,4-dihydroxybenzophenone, oxybenzone, 4-hydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone and 2,2'-dihydroxy-4-methoxybenzophenone, were the target analytes subjected to chlorination. The products of these BPs after chlorination were directly injected to the 2D-LC system for analysis. The results indicated that most TPs may be less toxic than their parent chemicals, but some may be more toxic, and that intestinal toxicity of TPs may be more obvious than blood toxicity. The proposed method is time-saving, high-throughput, and reliable, and has great potential for predicting toxicity or bioactivity of unknown and/or known components in a complex sample. Graphical Abstract The scheme for the 2D-LC online prediction of toxicity of the transformation products of benzophenone-type UV filters after chlorination.

Construction of a portable sample preparation device with a magnetic poly(methacrylic acid-co-ethylene dimethacrylate) monolith as the extraction medium and its application in the enrichment of UV filters in water samples.

A portable sample preparation device with a magnetic polymer monolith as the extraction medium was constructed. The monolith was synthesized by polymerizing methacrylic acid and ethylene dimethacrylate around a cylindrical magnet. In this way, the monolith with a magnetic core could be readily attached to the extraction device by magnetism. The constructed device was evaluated for the enrichment of UV filters in water samples, followed by high-performance liquid chromatographic analysis. The extraction efficiency for the targets was satisfactory with no matrix interference. Good linearities were obtained for the UV filters with the correlation coefficients >0.9986. The limits of detection and quantification for the UV filters were 0.3-0.8 and 1.0-2.4 ng/mL, respectively. The recoveries of the UV filters from the spiked water samples at the concentration of 100 ng/mL were 95.3-101.7%, with relative standard deviations <10%. Accordingly, the proposed portable device was demonstrated to be suitable for on-site simultaneous sampling, purification, and preconcentration within a single step.

Rapid enrichment of phosphopeptides by SiO2-TiO2 composite fibers.

SiO2-TiO2 composite fibers, prepared by electrospinning, were successfully applied to the rapid enrichment of phosphopeptides using a lab-in-syringe approach for the first time. Because of their large surface area, mesoporous structure, extraordinary length and appropriate Lewis acidity, the as-prepared SiO2-TiO2 composite fibers exhibited high selectivity and capacity in the enrichment of phosphopeptides from the digestion mixture of ß-casein and bovine serum albumin (BSA), as well as human blood serum and nonfat milk. The targeted phosphopeptides could be easily enriched and detected even when the total amount of ß-casein was decreased to only 10 fmol, indicating the high detection sensitivity of this method. In addition, the whole enrichment extraction procedure can be finished in less than 3 min, which can avoid or decrease the degradation of endogenous phosphoproteins by proteases released ex vivo during time-consuming treatments. The developed method is rapid, cost-effective, selective, sensitive, operationally simple, and does not require any harsh conditions and intricate equipment, providing an ideal candidate for the enrichment of phosphopeptides from complex biological samples either in the lab or in the field.

Application of dexmedetomidine for lung injury in elderly patients undergoing one-lung ventilation.

Introduction: This study aimed to evaluate the effects of dexmedetomidine (DEX) on lung injury, the oxygenation index and perioperative pulmonary complications in elderly patients who underwent thoracotomy with one-lung ventilation (OLV). Material and methods: A total of 120 elderly patients with lung cancer were included in the present study. According to the random number table method, these patients were randomly divided into two groups: group D and group C. Patients in group D were intravenously pumped with 0.5 µg/kg/h of DEX before anesthesia. The infusion was completed within 15 min, and anesthesia was induced by venous injection. Patients in group C were pumped with equal volumes of normal saline. Results: At T2 and T3, compared with group C, group D had a significant decrease in cardiac index, mean arterial pressure and central venous pressure (p < 0.05). At T2, T3 and T4, compared with group C, group D had a significant increase in pH and PaO2 (p < 0.05). At T2, T3 and T4, compared with group C, group D had a significant decrease in Qs/Qt (p < 0.05). At T6, compared with group C, group D had a significant decrease in the supernatant of bronchoalveolar lavage fluid of tumor necrosis factor-α and interleukin 6 (p < 0.05). At T5, compared with group C, group D had a significant decrease in Visual Analogue Scale score (p < 0.05), and a significant increase in Ramsay Sedation Scale score (p < 0.05), and the number of respiratory and cardiovascular events also decreased (p < 0.05). Conclusions: In elderly patients, dexmedetomidine can reduce Qs/Qt and increase PaO2 during OLV in surgery. It can reduce lung injury. Moreover, DEX reduced respiratory and cardiovascular complications in the perioperative period.

Porous monoliths: sorbents for miniaturized extraction in biological analysis.

In this review the focus is on application of porous monoliths to miniaturized extraction of biological analysis, with emphasis on porous monolithic materials and different miniaturized extraction formats. The general approaches used to synthesize organic polymer and silica monolithic materials are highlighted, and their properties and applicability are described and compared. Several extraction formats, including in-tube microextraction, chip-based microextraction, tip-based microextraction, among others, are reviewed in depth.

Magnetic solid-phase extraction based on magnetic carbon nanotube for the determination of estrogens in milk.

In this work, a novel method for the fabrication of magnetic carbon nanotubes based on 'aggregation wrap' was proposed. When carbon nanotubes and magnetic nanoparticles were vortically mixed in a solvent, the magnetic nanoparticles were wrapped into the carbon nanotube bundles that formed during the aggregation process, leading to the formation of magnetic carbon nanotubes. Thus, the resultant material can be separated from the solvent rapidly and conveniently by a magnet. Our investigation demonstrated that the 'aggregation wrap' mechanism for the preparation of magnetic composite is also applicable to other self-aggregated micro/nanomaterials, including graphene, graphite, C(60), etc. To testify the feasibility of the magnetic composites in sample preparation, the resultant magnetic carbon nanotubes were applied as sorbents for magnetic solid-phase extraction (MSPE) of estrogens in milk samples. Under optimized conditions, a rapid, convenient and efficient method for the determination of estrogens in milk samples was established by the combination of MSPE with high-performance liquid chromatography with fluorescence detector. The linearity range of the proposed method was 5-2000 µg/L with correlation coefficients (R) of 0.9983-0.9994. The limit of detection (LOD) for three estrogens ranged from 1.21 to 2.35 µg/L. The intra- and inter-day relative standard deviations (RSDs) were <9.3%. The reproducibility of the MSPE with different batches of magnetic carbon nanotubes was acceptable with RSD values <3.6%.

Clinical therapeutic effects of eradication of Helicobacter pylori in treating patients with type 2 diabetes mellitus: A protocol for systematic review and meta-analysis.

BACKGROUND: Previous studies have demonstrated that Helicobacter pylori is a critical factor in the development of gastrointestinal diseases. However, only limited studies have reported results on the relationship between H pylori infection and patients with type 2 diabetes mellitus (T2DM). Moreover, the conclusions from these past studies are variable. Because there are contradictory results on this issue, the present study aims to examine the clinical therapeutic impacts of H pylori eradication to treat patients experiencing T2DM. METHODS: The present protocol is drafted according to the provisions of the Preferred Reporting Items for Systematic Review and Meta-analyses Protocols guidelines. PubMed, Cochrane Central Register of Controlled Trials databases, EMBASE, Web of Science, China National Knowledge Infrastructure, and Chinese BioMedical Literature Database will be searched up to May 2021 to obtain randomized controlled trials evaluating the clinical therapeutic effects of H pylori eradication to treat patients experiencing T2DM. We will use 2 investigators independently to carry out study selection, data extraction, and employ the Cochrane Collaboration criteria to evaluate their risks of bias. Furthermore, we will apply Stata 16.0 software to perform data analysis. RESULTS: We intend to evaluate the clinical therapeutic impacts of H pylori eradication to treat patients suffering from T2DM. CONCLUSIONS: Our findings may support existing evidence on the clinical therapeutic impacts of H pylori eradication to treat patients with T2DM. ETHICS AND DISSEMINATION: Since all data will be extracted from the published literature, the study does not require an ethical approval. OSF REGISTRATION NUMBER: May 31, 2021.osf.io/qtexu. (https://osf.io/qtexu/).

Ventilation with a low tidal volume vs. an intermediate tidal volume during pleural decortication.

OBJECTIVE: This study aims to evaluate the effects of low tidal volume and positive end expiratory pressure (PEEP) combined with pressure-controlled ventilation-volume guaranteed (PCV-VG) ventilation on one lung ventilation (OLV) in patients with tuberculous destroyed lung (TDL). METHODS: Patients of two groups were all treated with volume controlled ventilation (VCV) on two-lung ventilation, and the tidal volume was set to 8 ml/kg according to standard body weight, breath rate was set to 10-14 times/min, inspiration and expiration ratio was set to 1:1.5. During OLV, VCV was used in group C, and the tidal volume was set to 8 ml/kg; PCV-VG was given to group P patients, and the tidal volume was set to 6 ml/kg, followed by PEEP at 7 cm H2O. Breath rate was set to 12-16 times/min, and inspiration and expiration ratio was set to 1:1.5 in both groups on OLV. RESULTS: Pplat, Ppeak and intrapulmonary shunt (Qs/Qt) were lower at T2 and T3 in group P, when compared to group C (P<0.05). At T2, T3 and T4, the oxygenation index (OI) increased, Qs/Qt decreased and arterial carbon dioxide partial pressure (PaCO2) increased in group P (P<0.05). At T5, the concentration of IL-6, TNF-α and BNP decreased in group P. CONCLUSION: Low tidal volume and PEEP combined with PCV-VG ventilation might be helpful for alleviating pulmonary injury in OLV, and reducing airway pressure and Qs/Qt during OLV in surgery. KEY WORDS: Destroyed lung, Low tidal volume, Low tidal volume, Positive end-expiratory pressure, Pressure-controlled ventilation, One lung ventilation.

Ventilation with a low tidal volume vs. an intermediate tidal volume during pleural decortication.

OBJECTIVE: This study aims to evaluate the effects of low tidal volume and positive end expiratory pressure (PEEP) combined with pressure-controlled ventilation-volume guaranteed (PCV-VG) ventilation on one lung ventilation (OLV) in patients with tuberculous destroyed lung (TDL). METHODS: Patients of two groups were all treated with volume controlled ventilation (VCV) on two-lung ventilation, and the tidal volume was set to 8 ml/kg according to standard body weight, breath rate was set to 10-14 times/min, inspiration and expiration ratio was set to 1:1.5. During OLV, VCV was used in group C, and the tidal volume was set to 8 ml/kg; PCV-VG was given to group P patients, and the tidal volume was set to 6 ml/kg, followed by PEEP at 7 cm H2O. Breath rate was set to 12-16 times/min, and inspiration and expiration ratio was set to 1:1.5 in both groups on OLV. RESULTS: Pplat, Ppeak and intrapulmonary shunt (Qs/Qt) were lower at T2 and T3 in group P, when compared to group C (P<0.05). At T2, T3 and T4, the oxygenation index (OI) increased, Qs/Qt decreased and arterial carbon dioxide partial pressure (PaCO2) increased in group P (P<0.05). At T5, the concentration of IL-6, TNF-α and BNP decreased in group P. CONCLUSION: Low tidal volume and PEEP combined with PCV-VG ventilation might be helpful for alleviating pulmonary injury in OLV, and reducing airway pressure and Qs/Qt during OLV in surgery. KEY WORDS: Destroyed lung, Low tidal volume, Low tidal volume, Positive end-expiratory pressure, Pressure-controlled ventilation, One lung ventilation.

Dispersive liquid-liquid microextraction coupled with dispersive micro-solid-phase extraction for the fast determination of polycyclic aromatic hydrocarbons in environmental water samples.

A new two-step microextraction technique, combining dispersive liquid-liquid microextraction (DLLME) and dispersive microsolid-phase extraction (D-micro-SPE), was developed for the fast gas chromatographic-mass spectrometric determination of polycyclic aromatic hydrocarbons (PAHs) in environmental samples. A feature of the new procedure lies in that any organic solvent immiscible with water can be used as extractant in DLLME. A special apparatus, such as conical-bottom test tubes, and tedious procedures of centrifugation, refrigeration of the solvent, and then thawing it, associated with classical DLLME or similar techniques are not necessary in the new procedure, which potentially lends itself to possible automation. In the present D-micro-SPE approach, hydrophobic magnetic nanoparticles were used to retrieve the extractant of 1-octanol in the DLLME step. It is noteworthy that the target of D-micro-SPE was the 1-octanol rather than the PAHs. Because of the rapid mass transfer associated with the DLLME and the D-micro-SPE steps, fast extraction could be achieved. Parameters affecting the extraction efficiency were investigated in detail. The optimal conditions were as follows: vortex at 3200 rpm in the DLLME step for 2 min and in D-micro-SPE for 1 min and then desorption by sonication for 4 min with acetonitrile as the solvent. The results demonstrated that enrichment factors ranging from 110- to 186-fold were obtained for the analytes. The limits of detection and the limits of quantification were in the range of 11.7-61.4 pg/mL and 0.04-0.21 ng/mL, respectively. The linearities were 0.5-50, 1-50, or 2-50 ng/mL for different PAHs. Finally, the two-step extraction method was successfully used for the fast determination of PAHs in river water samples. This two-step method, combining two different and efficient miniaturized techniques, provides a fast means of sample pretreatment for environmental water samples.

Chiral stationary phase based on cellulose derivative coated polymer microspheres and its separation performance.

Chiral stationary phases (CSPs) have always been research hotspot in enantiomer separation. Currently, most of the CSPs are based on silica platform. In this research, monodisperse, porous glycidyl methacrylate-divinylbenzene copolymer particles (poly(GMA-DVB)) were designed and prepared. Then the GMA was further reacted with ethylenediamine to introduce amino groups onto the polymer, which provide anchoring sites for cellulose derivatives. Herein, Cellulose-tris (3,5-dimethylphenylcarbamate) (CDMPC) was successfully coated onto the polymer microspheres, achieving a stable and successful CSP. The porous structure and the surface moieties of the CSPs were studied in detail. The chromatographic separation was optimized. Hexaconazole,methyl DL-mandelate,benzoin and tebuconazole have been successfully separated on the CSP column, with column efficiency as high as 10,200 plates/m, which is comparable with some silica-based CSPs. The research has indicated that the poly(GMA-DVB) is a promising candidate for constructing CSPs for chiral separation.

Fast separation of water-soluble vitamins by hydrophilic interaction liquid chromatography based on submicrometer flow-through silica microspheres.

In the present study, submicrometer flow-through silica microspheres (Sub-FTSiO2) was for the first time obtained via a suspension polymerization method coupled with sol-gel transition and phase separation. The Sub-FTSiO2 was characteristic of rich mesopores, penetrable macropores and small particle size, which would be beneficial to fast mass transfer, low column backpressure and high column efficiency. It was directly used as the hydrophilic interaction liquid chromatographic (HILIC) stationary phase, and the fast separation of seven water-soluble vitamins in 2.2 min was realized. The proposed method was successfully applied to the determination of water-soluble vitamins in two functional beverages on the market. The prepared Sub-FTSiO2 was well demonstrated for fast HILIC, and would be potential as the stationary phase matrix for fast liquid chromatography in diverse separation modes.

Preparation of a poly(N-isopropylacrylamide-co-ethylene dimethacrylate) monolithic capillary and its application for in-tube solid-phase microextraction coupled to high-performance liquid chromatography.

A poly(N-isopropylacrylamide-co-ethylene dimethacrylate) (poly(NIPAAm-co-EDMA)) monolith was in situ prepared in the capillary and was investigated for in-tube solid-phase microextraction (SPME). NIPAAm, an acrylamide monomer with isopropyl group, was crosslinked with EDMA. PEG of 400-20,000 Da molecular weight and methanol were selected as the binary porogens. The porous structures of the resulting monoliths have been assessed by SEM, nitrogen adsorption-desorption, and pressure drop measurements. To investigate the extraction mechanism, several groups of model analytes (including neutral, acidic, and basic) were examined. The result showed that this monolithic material exhibited high extraction efficiencies for compounds under highly acidic and basic conditions, which was due to the hydrophobic interactions and excellent pH stability of the monolith. The equilibrium extraction time profiles were also monitored for model compounds to evaluate the extraction capacity of monolithic capillary. Finally, the developed monolith in-tube SPME-HPLC method was applied to the determination of three tricyclic antidepressants from urine samples.

Waxberry-like hierarchically porous ethyl-bridged hybrid silica microsphere: A substrate for enzyme catalysis and high-performance liquid chromatography.

In this study, the ethyl-bridged hybrid silica microsphere with hierarchically meso-macroporous structure was initially synthesized through a method combining dispersion polymerization with sol-gel transition and phase separation. The flow-through macropores rendered the microsphere a rough surface like a waxberry, and thus the material was named as waxberry-like ethyl-bridged hybrid silica sphere (WEHS). WEHS was characteristic of appropriate alkali-stability, which was highly difficult for the pure silica. Additionally, WEHS possessed hierarchical meso- and macropores, which added additional value for faster mass transfer than the conventional fully porous silica materials. Taking the advantages of WEHS, it was successfully applied as the substrate to immobilize lipase; the prepared immobilized lipase exhibited high catalytic activity and favorable reusability under alkaline conditions, which was significant in pitch control of neutral-alkaline papermaking industry. Moreover, as the high-performance liquid chromatographic stationary phase matrix, WEHS made the separation under alkaline mobile phase into a reality for the silica-based materials. Besides, an ultra-fast and efficient separation in minutes was achieved with lower consumption of solvents and saving analytical time, which is highly desired in modern analysis. In general, WEHS was a novel and promising candidate in the myriads of silica-based materials.

Application of alveolar recruitment strategy and positive end-expiratory pressure combined with autoflow in the one-lung ventilation during thoracic surgery in obese patients.

BACKGROUND: The present study aims to evaluate the influence of alveolar recruitment strategy (ARS) and positive end-expiratory pressure (PEEP) combined with autoflow on respiratory mechanics, the oxygen index (OI), pulmonary shut [Qs/Qt(%)], and the concentrations of IL-6 and TNF-α in venous blood after surgery in obese patients who experienced thoracic surgery with one-lung ventilation (OLV). METHODS: A total of 36 obese patients with ASAII-III degree, who experienced selective pulmonary lobectomy, were within 36-74 years old, and had a BMI of 30-40 kg/m2, were randomly divided into two groups: control group (C group) and protective ventilation group (P group). In the P group, ARS was given once when OLV began. Then, ventilation at 7 mmHg of PEEP and autoflow were given. The Ppeak before OLV (T1), at 30 minutes after OLV (T2), and at the 5 minutes after two-lung ventilation (TLV) (T3), and the changes of Pplat and Cdyn were recorded. Then, arteriovenous blood was drawn at T1, T2, T3 and T4 (6 hours after the operation), blood-gas indicators, including SPO2, PaCO2 and PaO2, were measured, and the value of Qs/Qt(%) was calculated. Afterwards, venous blood was collected at T1 and T5 (18 hours after surgery), and the concentrations of IL-6 and TNF-α were detected. The clinical pulmonary infection score (CPIS) was determined at the first day and seventh day after the operation. RESULTS: In both groups, Cdyn and OI decreased, while Pplat, Ppeak and Qs/Qt(%) increased (P<0.05) at T2, when compared with those at T1. At T2 and T3, Pplat and Ppeak decreased (P<0.05) in the P group, when compared with the C group. At T2, T3 and T4, OI increased (P<0.05) in the P group, when compared with the C group. At T2, T3 and T4, PaCO2 and Qs/Qt(%) decreased in the P group, when compared with the C group. The concentrations of IL-6 and TNF-α decreased in the P group, when compared with the C group. CONCLUSIONS: The ventilation model of ARS and PEEP combined with autoflow can better reduce airway pressure and the production of injurious inflammatory cytokines in blood in obese patients. Furthermore, it can reduce Qs/Qt during and at 6 hours after thoracotomy, improve OI and maintain the acid-base balance of the internal environment, which may be applied in clinical work. This brings new enlightenment and needs to be clarified through further studies.

Preparation of pH-responsive stationary phase for reversed-phase liquid chromatography and hydrophilic interaction chromatography.

Novel pH-responsive polymer-grafted silica was successfully synthesized through the radical "grafting from" polymerization on azo initiator-immobilized silica. The immobilization of azo initiator onto the silica surface was achieved by the reaction of surface amino groups with 4,4'-azobis(4-cyanovaleric acid chloride). The polymer-grafted silica was prepared by stirring suspension of the azo initiator-immobilized silica in anhydrous dioxane containing acrylic acid (AAc) and butyl acrylate (BA). The resulting polymer-grafted silica was demonstrated to be pH responsive to hydrophobic/hydrophilic property by reversed-phase liquid chromatography (RPLC) and hydrophilic interaction chromatography (HILIC). In RPLC mode, the retention of aromatic compounds decreased with the increase in the pH of mobile phase. However, the opposite result was obtained in HILIC mode; the retention of soybean isoflavones was stronger with the mobile phase at higher pH. Finally, the separations of sulfonamides and soybean isoflavones were carried out in RPLC mode and the separation of some nucleotides was achieved in HILIC mode.