Low-pressure Liquid Research Articles

Laboratory Innovation Project of Substance Separation and Detection Using Self-Made Low-Pressure Liquid Chromatography

Laboratory Innovation Project of Substance Separation and Detection Using Self-Made Low-Pressure Liquid Chromatography

Theoretical predictions to facilitate the method development in slalom chromatography for the separation of large DNA molecules

Slalom chromatography (SC) re-emerged in 2024 due to the availability of low adsorption ultra-high pressure liquid chromatography (UHPLC) packed columns/instruments and large modalities being investigated in the context of cell and gene therapies. The physico-chemical principles of SC retention combined with hydrodynamic chromatography (HDC) exclusion have been recently reported. In SC, DNA macromolecules are retarded because: (1) they can be stretched to lengths comparable to the particle diameter, and (2) their elastic relaxation time is long enough to maintain them in non-equilibrium extended conformations under regular UHPLC shear flow conditions. Here, a quantitative HDC-SC retention model is consolidated. A general plate height model accounting for the band broadening of long DNA biopolymers along packed beds is also derived for supporting method development and predicting speed-resolution performance in SC.For illustration, the chromatographic speed-resolution properties in SC are predicted for the separation of specific critical pairs (4.0/4.5, 10/11, and 25/27 kbp) of linear dsDNA polymers. The calculations are performed for two available custom-made particle sizes, dp= 1.7 and 2.5μm, at a constant pressure of 10,000 psi. The predictions are directly validated from experimental data acquired using low adsorption MaxPeakTM 4.6 mm i.d. Columns packed with 1.7μm BEHTM 45 Å (15 cm long column) and 2.5μm BEH 125 Å (30 cm long column) Particles, and by injecting six linear dsDNAs (λ DNA-Hind III Digest). The LC system is very low dispersion ACQUITYTM UPLCTM I-class PLUS System, and the mobile phase is a 100 mM phosphate buffer at pH 8. Maximum resolution is always achieved when the average extended lengths of linear dsDNAs are equal to a critical length, which is proportional to the particle diameter and to the square root of the applied shear rate. Most advantageously, the experimental results reveal that the relaxation times of linear dsDNAs observed under shear flow conditions are two orders of magnitude shorter than those expected in the absence of flow: this enables the detection of the longest linear dsDNAs up to 25 kbp without irremediable loss in column performance. Finally, the retention-efficiency model elaborated in this work can be used to rapidly anticipate and develop methods (selection of particle size, column length, and operating pressure) for any targeted DNA and time-resolution constraints.

Recycling preparative isolation of six bicyclol active metabolites from SD rat urine using macroporous resin, offline 2D LPLC/HPLC, and prep-HPLC combined with pharmacodynamic evaluation of two active metabolites

In our previous study, several bicyclol (BIC) metabolites were found to possess higher solubility, security, and efficacy than the parent drug. However, further research can’t be conducted without monomeric metabolites. In the current study, a highly efficient preparative approach for six BIC-active metabolites from Sprague-Dawley (SD) rat urine was developed. First, 1000 mL of urine was purified and concentrated to 50 mL using microporous resin. Second, middle chromatogram isolated (MCI) GEL®CHP20P adsorbent was used to create a low-pressure liquid chromatography (LPLC) column, which was combined with high-performance liquid chromatography (HPLC) to build an offline 2D system to visualize the separation process. Samples were segmented into 25 tubes and merged into three fractions. Then, recycling preparative HPLC was applied to the monomeric preparation to improve the efficiency. The prepared metabolites possessed high purity (greater than98%), and were verified by nuclear magnetic resonance (NMR). Finally, an isoniazid (INH)-induced liver injury zebrafish model was established to evaluate the efficiency of the BIC, M7, and M8 metabolites. The M7 metabolite exhibited a higher efficiency than BIC in histopathology, gene expression, and aminotransferase levels. Consequently, this study provided a strategy that integrating modern analytical techniques to prepare metabolites for discovering high value candidate compounds from biological metabolism.

Platinum-Based Nanoparticle Fuel Cell Catalysts Synthesized By Sputtering Onto Liquid Substrates

The quest of finding cheaper and better fuel cell catalyst materials has been long ongoing and remains a crucial step in making fuel cells a commercially viable technology. Platinum (Pt) is still the conventional catalyst used in proton exchange membrane (PEM) fuel cells, however, with slow cathode kinetics and high material cost. Platinum-rare earth (RE) and lanthanide alloys have been found to greatly enhance the catalytic activity towards the oxygen reduction reaction (ORR).1 Increases in ORR activity of up to one order of magnitude compared to pure platinum has been observed for these alloys, but high oxygen affinity of the RE alloying agents considerably complicates their synthesis. Sputter deposition into low vapor pressure liquid substrates, such as ionic liquids and certain polymers enables fabrication of clean nanoparticles, without the presence of air and other contaminates, making it a potential technique for Pt-RE nanoparticle synthesis.Here, we will present our recent work on magnetron sputtering of Pt 2 and Pt-alloys into different liquid substrates, including polyethylene glycol and three imidazolium-based ionic liquids. We have investigated the influence of substrate temperature on Pt nanoparticle growth during sputtering, and in post-sputtering heat treatment.2 We show that whilst substrate temperature influences the Pt nanoparticle size, the effect is not as great as for other materials. Better understanding the growth processes of Pt nanoparticles sputtered into liquids is an important step towards tunable sizes and catalytic activities of Pt-RE nanocatalysts. Escudero-Escribano, María, et al. "Tuning the activity of Pt alloy electrocatalysts by means of the lanthanide contraction." Science 352.6281 (2016): 73-76.Brown, Rosemary, et al. "Plasma-Induced Heating Effects on Platinum Nanoparticle Size During Sputter Deposition Synthesis in Polymer and Ionic Liquid Substrates." Langmuir 37.29 (2021): 8821-8828.

A Review on the Usage of Main Secondary Metabolites of Crocus sativus in Cancer Treatments

Saffron is the world’s second most costly spice, with numerous advantages of culinary, cosmetics, pharmaceutical and medical fields. There is an inadequate awareness of how Crocus sativus L. (Family Iridaceae) which produces the spice saffron from the filaments that grow inside the flower, can possibly treat cancer. Since, cancers are regarded as a devastating disease in today's world, anticancer and antioxidant properties of secondary metabolites available in saffron will be highly invaluable. The present review focuses on investigating on the role of crocin, crocetin and safranal in cancer treatments, which are the main secondary metabolites of C. sativus, and evaluating the various methods of extracting, isolating and analysing them. The review conducted using subjective indexed journal articles that were published over the past ten years. Out of the available data, it found that crocin would be quite beneficial in healing cancer without revealing any adverse effects. Crocin showed immense potential in curing a wide range of cancer types, mainly prostate and lung cancers, by eliminating cancer cells through apoptosis and inhibiting tumour invasion. There were a limited number of researches conducted using crocetin and safranal. However, they will approve for cancer treatments shortly. Crocetin was widely employed as a chemo-preventive and anti-inflammatory medication for pancreatic and breast cancer treatments. It has recently been utilized only for treatments of few types of cancers. Only one publication recorded in the recent ten years, as the usage of safranal in cancer treatment, which was against leukaemia. Moreover, secondary metabolite analysis techniques including spectrophotometry and chromatography utilized effectively, whereas predominantly improved extraction techniques including ultrasound-assisted extraction, emulsion liquid membrane, high hydrostatic pressure extraction. The analysis affirmed that, microwave[1]assisted extraction (80±1%) followed by low-pressure liquid chromatography (99.04±0.01%) showed optimum recovery of crocin. Whereas for safranal, microwave-assisted extraction (15.9±0.1%) and ultraviolet (UV) spectrophotometry preferred methods. The analysed data will be useful for future studies that focus on the analysis of saffron secondary metabolites and potentiality in cancer treatments to provide the researchers with a wide range of alternatives for carrying out the processes of curing cancers.
 Keywords: Anticancer, Crocin, Crocetin, Safranal, Saffron

Strength optimization of low-pressure transient liquid phase bonded Ti–6Al–4V similar joint with Cu–Ni multi-interlayer

The pressure reduction of transient liquid phase bonding (TLPB) technique with sound Ti–6Al–4V similar joint is reported. Eliminating brittle intermetallic compounds (microstructural homogenization) and voids at the interface (void closure) is critical for sound joints with bending strength above the yield strength of Ti–6Al–4V. These two goals are achieved by adjusting the holding time (0.5–12 h) and bonding pressure (0.001–0.3 MPa) at a fixed bonding temperature of 950 °C below the phase transus of the substrates. The maximum bending strength of 1570 MPa is obtained with joint having a homogenized microstructure without any voids under joining condition held for 12 h with 0.03 MPa corresponding to 3% of the conventional TLPB technique. The holding time for microstructural homogenization is reduced with 0.3 MPa bonding pressure by liquid push-off from the interface. Low-pressure TLPB is recommended for cost reduction and ensuring shape accuracy of complex geometry components.

Mechanism of the insulator-to-metal transition and superconductivity in the spin liquid candidate NaYbSe2 under pressure

The quantum spin liquid candidate NaYbSe2 was recently reported to exhibit a Mott transition under pressure. Superconductivity was observed in the high-pressure metallic phase, raising the question concerning its relation with the low-pressure quantum spin liquid ground state. Here we combine the density functional theory and the dynamical mean-field theory to explore the underlying mechanism of the insulator-to-metal transition and superconductivity and establish an overall picture of its electronic phases under pressure. Our results suggest that NaYbSe2 is a charge-transfer insulator at ambient pressure. Upon increasing pressure, however, the system first enters a semi-metallic state with incoherent Kondo scattering against coexisting localized Yb-4f moments, and then turns into a heavy-fermion metal. In between, there may exist a delocalization quantum critical point responsible for the observed non-Fermi liquid region with linear-in-T resistivity. The insulator-to-metal transition is therefore a two-stage process. Superconductivity emerges in the heavy-fermion phase with well-nested Yb-4f Fermi surfaces, suggesting that spin fluctuations may play a role in the Cooper pairing. NaYbSe2 might therefore be the 3rd Yb-based heavy-fermion superconductor with a very “high” Tc than most heavy-fermion superconductors.

Li-ion solvation in TFSI and FSI -based ionic liquid electrolytes probed by X-ray photoelectron spectroscopy

For Li-ion batteries, the Li-ion solvation in liquid electrolytes is a crucial parameter affecting directly the electrochemical cycling performance. X-ray photoelectron spectroscopy (XPS) can play an essential role for investigating the cation and anion electronic structure and monitoring the Li-ion solvation into various solvent and salt environments. In this contribution, we demonstrate the capability of conventional laboratory XPS using Al Kα X-ray source to determine the anions solvation shell of Li+ cation within the low vapour pressure and vacuum compatible ionic liquid electrolytes. 1M of LiTFSI and 1M of LiFSI salts dissolved in (EMIM+-FSI-) and (EMIM+-TFSI-) ionic liquids respectively are investigated by acquiring the F1s, N1s, C1s, S2p and Li1s core levels. The binding energy difference between the N1s component originating from the EMIM+ cation and the N1s component originating from TFSI- or FSIanions solvating the Li+ confirms that both TFSI- and FSIcontribute simultaneously to the Li+ solvation. Additionally, the stability of the TFSI and FSI -based ionic liquid electrolytes is carefully discussed for long X-ray exposure times.

Strategy Targets Risk Management for CO2 Waterless Fracturing

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 30437, “Risk Management and Control for CO2 Waterless Fracturing,” by Siwei Meng, Qinghai Yang, SPE, and Yongwei Duan, PetroChina, et al., prepared for the 2020 Offshore Technology Conference Asia, originally scheduled to be held in Kuala Lumpur, 2–6 November. The paper has not been peer reviewed. Copyright 2020 Offshore Technology Conference. Reproduced by permission. Given shortages and uneven distribution of water resources in China, efforts must be made to develop waterless fracturing techniques. The fluid experiences high pressures and low temperatures during carbon dioxide (CO2) waterless fracturing operations, which can lead to accidents and environmental pollution. In the complete paper, a safety-management approach and a contingency plan for such operations are developed. At the time of writing, this CO2 waterless fracturing methodology has been completed successfully more than 20 times. Surface Process Work Flow of CO2 Waterless Fracturing The basic process of a CO2 waterless fracturing operation is shown in Fig. 1. First, several CO2 storage tanks are connected in parallel. The booster, sealed blender, fracturing pump (all mounted on trunks), and wellhead equipment are connected. The measuring trunk communicates with each vehicle to monitor operation status. Proppant is put into the sealed blender, into which liquid CO2 is injected for pre-cooling. Pump testing is conducted on the high-pressure line and the wellhead and the low-pressure liquid supply line is pressure-tested. Operation does not proceed until pressure-testing results are positive. Afterward, liquid CO2 is injected into formations to fracture them and, moreover, extend created fractures. The sealed blender is enabled to inject prop-pants, and displacement begins after the end of proppant injection. Finally, a series of tasks, including well shut-in for soaking and flowback, is carried out successively.

Characteristics and Controlling Factors of Nanopores of the Niutitang Formation Shale from Jiumen Outcrop, Guizhou Province.

This paper studies the characteristics and controlling factors of nanopores in organic-rich shale in the Niutitang Formation. Six samples were collected from the bottom of the formation at the Jiumen Outcrop, Guizhou Province. Experiments were conducted to investigate the pore structures of these high-maturity shale samples. The TOC contents vary between 4.81-17.51% with an average of 10.18%. The XRD data show that these samples are dominated by quartz (44%-71%), with a significant amount of clay minerals, such as illite, with a content of 8%-27.5%. Based on the low-pressure liquid N₂ sorption measurements, the pore structures can be divided into two groups. Group A including samples of N-2, N-3 and N-4, mainly develop slit-shaped pores, mesopores and macropores. Group B shown from samples N-1, N-5 and N-6, are mainly composed of narrow slitlike pores, which may provide more space for shale gas than slit-shaped pores. The mesopores, macropores, porosity and specific surface areas of group B are more developed than those of group A. With the comparison of pore structures in shales with various organic matter and mineral contents, the dissolution of quartz and feldspar can be the important factor controlling pore development. The evolution of diagenesis is closely related to pore evolution. This diagenesis has various types and complex effects on the pores, mainly including compaction, dissolution and cementation.

Pronounced structural crossover in water at supercritical pressures

There have been ample studies of the many phases of H2O in both its solid and low pressure liquid states, and the transitions between them. Using molecular dynamics simulations we address the hitherto unexplored deeply supercritical pressures, where no qualitative transitions are thought to take place and where all properties are expected to vary smoothly. On the basis of these simulations we predict that water at supercritical pressures undergoes a structural crossover across the Frenkel line at pressures as high as 45 times the critical pressure. This provides a new insight into the water phase diagram and establishes a link between the structural and dynamical properties of supercritical water. Specifically, the crossover is demonstrated by a sharp and pronounced at low pressures, and smooth at high pressures, signified by changes in the pair distribution functions and local coordination which coincide with the dynamical transition (the loss of all oscillatory molecular motion) at the Frenkel line on the phase diagram.

Performing flow injection chromatography using a narrow open tubular column

Flow injection chromatography (FIC) or sequential injection chromatography (SIC) is a low-pressure liquid chromatography technique that uses flow injection or sequential injection hardware. Due to the constraints of this hardware, the separation resolution is low; often no more than 3–5 components are resolved. We have recently demonstrated the excellent resolving power of narrow open tubular (OT) columns for various biomolecules, and only moderate elution pressures are needed to carry out these separations. In this paper, we incorporate a narrow OT column with FIC and construct an FIC system using a pressure chamber and two injection valves to implement gradient elution. The resultant system not only improves the resolution but also reduces the system cost. When we use the system to separate peptides from trypsin-digested cytochrome C, we can resolve dozens of peptides (with resolutions of 0.5 or greater) at a speed of 12 samples per hour. When we use this system to separate a mixture containing 3 amino acids, we can base-line resolve these compounds at a speed of 1800 sample per hour.

Crystallisation and zircon saturation of calc-alkaline tonalite from the Adamello Batholith at upper crustal conditions: an experimental study

The understanding of the geochemical and petrophysical evolution of magmas forming intermediate calc-alkaline batholiths at shallow crustal levels critically depends on knowledge of the phase equilibria relations along the liquid line of descent. Here, we present experimental results for a tonalitic system at a pressure of 200 MPa and under water-saturated conditions. Melting experiments were performed at temperatures between 700 and 1000 °C in externally heated HCM pressure vessels, with oxygen fugacity controlled close to the Ni–NiO buffer equilibrium (NNO) employing an argon–methane mixture as pressure medium and Co–Pd redox sensors to verify fO2 conditions. Natural rock powder of a medium-K tonalite from the Adamello Batholith in Northern Italy served as experimental starting material. Based on compositional data of stable phases in the run products and images of entire run charges, mass balance calculations as well as image processing were performed to investigate the evolution of the crystal/melt ratio with respect to temperature. Furthermore, compositional trends of minerals as well as the liquid line of descent of residual melts were obtained. Orthopyroxene, clinopyroxene and plagioclase were identified as near-liquidus phases (below 990 °C). At 900 °C, amphibole joins the solid-phase assemblage at the expense of clinopyroxene, indicating the existence of a peritectic relationship. After an initial near-linear decrease with temperature, residual melt fractions exhibit a plateau of 45–55 vol. % between 750 and 850 °C, followed by a rapid decrease coinciding with quartz saturation at 725 °C. Compositions of residual liquids evolve along a typical calc-alkaline differentiation trend with decreasing temperature (increasing SiO2 and decreasing TiO2, Al2O3, CaO, MgO and FeO contents) and become peraluminous below 900 °C. Intermediate to acidic rocks from the Adamello follow the experimental liquid line of descent indicating that the observed compositional spread of the natural intermediate composition rock record can be explained by low-pressure magma differentiation and liquid extraction. Experimentally determined zircon saturation levels are at low temperatures distinctly lower compared to existing and often used Zr-saturation models, but fully consistent with observed and modelled Zr-evolution trends from the natural rock record of the Southern Adamello Batholith inferring that zircon saturation in these intermediate to felsic plutonic rocks occurred at 800–830 °C corresponding to a melt fraction of about 50 vol. %.

100 Micrometer bore open tubular capillary column modified with linear co-polymer chains for application in low pressure liquid chromatography

The performance of a 100 um i.d. open tubular column modified with linear co-polymer chains has been explored under low pressure operating conditions. A 512 mm fused-silica capillary was reacted with 3-chloropropyl isocyanate followed by sodium diethyldithiocarbamate. A copolymer layer was then immobilized on the inner surface via reversible addition-fragmentation transfer polymerization of styrene, methacrylic acid and N-phenylacrylamide. The thickness of the polymer layer was ca 1.5 µm. The column was evaluated for the separation of a mixture composed of three peptides (Trp-Gly, angiotensin I, bradykinin). The number of theoretical plates (N) as high as 72,100 plates/column (corresponding to 140,800/m, 7.10 µm plate height) was achieved. The column to column and day to day reproducibility of our columns was found better than 2.1%. For comparison purpose, similar chromatographic data for a selected analyte was also obtained with a commercial microcolumn of 0.5 mm id packed with a conventional C18 phase (5 µm), and 17 µm was the plate height obtained at the optimum flow rate. The van Deemter plots and kinetic plots were also obtained for comparison between our open tubular capillary column and the commercial packed column of a narrow id.

Phenomena identification and ranking table exercise for thorium based molten salt reactor-solid fuel design

Thorium based molten salt reactor-solid fuel (TMSR-SF) design is an innovative reactor concept that uses high-temperature tristructural-isotropic (TRISO) fuel with a low-pressure liquid salt coolant. In anticipation of getting licensed applications for TMSR-SF in the future, it is necessary to fully understand the significant features and phenomena of TMSR-SF design, as well as its transient behavior during accidents. In this paper, the safety-relevant phenomena, importance, and knowledge base were assessed for the selected events and the transient of TMSR-SF during station blackout scenario is simulated based on RELAP/SCDAPSIM Mod 4.0. The phenomena having significant impact but with limited knowledge of their history are core coolant bypass flows, outlet plenum flow distribution, and intermediate heat exchanger (IHX) over/under cooling transients. Some thermal hydraulic parameters during the station blackout scenario are also discussed.

In-plane doping profile control of plate-like organic single crystals grown by a method combining electrospray and low vapor pressure liquid film

Although the molecular doping of single crystal organic semiconductors is expected as a key technology that imparts attractive functions in optical and electrical properties, the doping technology in single crystal organic material is still in the initial stages. In this study, doping profile control in the organic single crystal was examined by using an organic single crystal growth method in which a low vapor pressure liquid thin film is used as a crystal growth field and solutes are supplied by electrospray deposition. Steep doping profile control with a transition region of around 1–2 μm was demonstrated using dopants of small molecule red dye and green fluorescent polymer into plate-like single crystal of widegap fluorescent small molecule. We also evaluated the doping profile of the small molecule red dye in microwire-like single crystals of green fluorescent metal complex small molecule.

Popularization and application of the capillary foam deliquification technology in horizontal wells with low pressures and low liquid flow rates: A case study on middle–shallow gas reservoirs in the Western Sichuan depression

The application effect of the foam deliquification technology in horizontal wells is poor because the foaming agent fails to reach the target location. In view of this, the adaptability of the capillary foam deliquification technology in the Western Sichuan Gas Field in the Sichuan Basin was analyzed from the aspects of gas flow rate, liquid flow rate and casing program of gas wells, and the design of injection depth and the selection of capillary size, tool string parameters (the maximum length and the minimum counterweight) and foam deliquification parameters (foaming agent type selection, ground injection concentration and rate) were optimized. Then, a standardized capillary operation process was developed. Finally, a field application test was carried out. And the following research results were obtained. First, the capillary foam deliquification technology has a popularization potential in the horizontal wells of middle–shallow depth, low pressure and low liquid flow rate, but it is not suitable for the wells with too low gas flow rate, too high liquid flow rate or too high condensate content. Second, the well deviation angle at the injection depth shall be between 70° and 80°, the selection of capillary size shall satisfy the requirement for tension strength by the well depth, the foam deliquification parameters shall be optimized based on the specific well conditions and the liquid loading characteristics, and the capillary operation shall comply with the standardized process. Third, by the end of July 2017, the capillary foam deliquification technology had been successfully applied in 9 horizontal wells in the Western Sichuan Gas Field with a cumulative gas increment of 295 × 104 m3. Fourth, 4 supporting technologies of the capillary foam deliquification are formed, including capillary sticking prevention, integrated agent injection and pressure measurement, combined cleaning and deliquification and capillary wellhead suspension. In conclusion, the capillary foam deliquification technology provides a technological support for the deliquification and production stabilization of horizontal wells with middle–shallow depth, low pressures and low liquid flow rates in the Western Sichuan Depression, and also provides technological reference for the deliquification of horizontal wells in the similar type of gas reservoirs.

A Method for the Isolation and Characterization of Mycosporine-Like Amino Acids from Cyanobacteria.

This report provides a broadly applicable and cost-effective method for the purification of mycosporine-like amino acids (MAAs) from cyanobacteria. As MAAs are known to have multiple bioactivities for health and beauty, a universal isolation method of MAAs from biomass is attractive. In particular, the biomass of photosynthetic microorganisms such as cyanobacteria is of interest as a natural source of useful compound production, because of their photoautotrophic property. The method presented here is applicable for the isolation of mycosporine-2-glycine (M2G), which is a rare MAA produced in a halotolerant cyanobacterium. This method also allowed for the isolation of two of the most common MAAs, shinorine (SHI) and porphyra-334 (P334). A three-step separation process using low pressure liquid chromatography yielded purified MAAs, which were characterized by nuclear magnetic resonance (NMR) and liquid chromatography-mass spectrometry (LC/MS) analyses. The purified MAAs exhibited free radical scavenging activity in the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. The experimental parameters obtained in this report may allow for a scale-up of the MAA purification process for future industrial applications.

Effects of a 15-month anti-TNF-\u03b1 treatment on plasma levels of glycosaminoglycans in women with rheumatoid arthritis

BackgroundIn this study, the effect of 15-month anti-tumor necrosis factor alpha (TNF-α) treatment on circulating levels of plasma sulfated glycosaminoglycans (GAGs) and the nonsulfated GAG hyaluronic acid (HA) in female rheumatoid arthritis (RA) patients was assessed.MethodsPlasma was obtained from healthy subjects and RA women treated with TNF-α antagonists (etanercept or adalimumab or certolizumab pegol) in combination with methotrexate. GAGs were isolated from plasma samples using ion exchange low-pressure liquid chromatography. Total sulfated GAGs were quantified using a hexuronic acid assay. Plasma levels of keratan sulfate (KS) and HA were measured using immunoassay kits.ResultsTotal sulfated GAGs and HA levels were higher in female RA patients before treatment in comparison to healthy subjects. KS levels did not differ between RA women and controls. Anti-TNF-α treatment resulted in normalization of plasma total GAG and HA levels in RA patients, without any effect on KS levels.ConclusionsOur results suggest that anti-TNF-α therapy has a beneficial effect on extracellular matrix remodeling in the course of RA.

Co-extraction of vanadium and chromium from high chromium containing vanadium slag by low-pressure liquid phase oxidation method

High chromium containing vanadium slag is refractory, and therefore cannot be processed efficiently by traditional roasting method. In this study, a low pressure leaching process using NaOH solution to co-extract both vanadium and chromium has been proposed. The effects of NaOH concentration, leaching temperature, oxygen pressure, and liquid-to-solid mass ratio on the vanadium and chromium leaching rate were discussed in detail. The results suggested that the NaOH concentration and leaching temperature were more influential factors for the extraction of vanadium and chromium. Under the optimal reaction conditions (temperature 200 °C, liquid-to-solid mass ratio of 6:1, NaOH mass concentration of 50%, agitation speed 700 rpm, pressure of 1 MPa, and reaction time 180 min), the recoveries of vanadium and chromium could reach up to 98.3% and 93.3%, respectively. The kinetics study indicated that the dissolution process of vanadium slag followed the shrinking core model, and the extraction of vanadium and chromium were both governed by the internal diffusion control. Furthermore, the apparent activation energies for the oxidation of vanadium and chromium were calculated to be 27.58 and 36.74 kJ/mol, respectively. The result from this study provides insights on effectively co-extracting V and Cr from high Cr-containing vanadium slag while minimizing the environmental contamination.