Vedolizumab serum trough concentrations with and without thiopurines in ulcerative colitis: The prospective VIEWS pharmacokinetics study

BACKGROUND Ulcerative colitis(UC)is a chronic inflammatory condition requiring continuous treatment and monitoring.There is limited pharmacokinetic data on vedolizumab during maintenance therapy and the effect of thiopurines on vedolizumab trough concentrations is unknown.AIM To investigate the exposure-response relationship of vedolizumab and the impact of thiopurine withdrawal in UC patients who have achieved sustained clinical and endoscopic remission during maintenance therapy.METHODS This is a post-hoc analysis of prospective randomized clinical trial(VIEWS)involving UC patients across 8 centers in Australia from 2018 to 2022.Patients in clinical and endoscopic remission were randomized to continue or withdraw thiopurine while receiving vedolizumab.We evaluated vedolizumab serum trough concentrations,presence of anti-vedolizumab antibodies,and clinical outcomes over 48 weeks to assess exposure-response asso-ciation and impact of thiopurine withdrawal.RESULTS There were 62 UC participants with mean age of 43.4 years and 42%were females.All participants received vedolizumab as maintenance therapy with 67.7%withdrew thiopurine.Vedolizumab serum trough concentrations remained stable over 48 weeks regardless of thiopurine use,with no anti-vedolizumab antibodies detected.Pa-tients with clinical remission had higher trough concentrations at week 48.In quartile analysis,a threshold of>11.3μg/mL was associated with sustained clinical remission,showing a sensitivity of 82.4%,specificity of 60.0%,and an area of receiver operating characteristic of 0.71(95%CI:0.49-0.93).Patients discontinuing thiopurine required higher vedolizumab concentrations for achieving remission.CONCLUSION A positive exposure-response relationship between vedolizumab trough concentrations and UC outcomes suggests that monitoring drug levels may be beneficial.While thiopurine did not influence vedolizumab levels,its with-drawal may necessitate higher vedolizumab trough concentrations to maintain remission.

Impact of Pollutant Concentration and Particle Deposition on the Radiative Flow of Casson-Micropolar Fluid between Parallel Plates

Assessing the behaviour and concentration of waste pollutants deposited between two parallel plates is essential for effective environmental management.Determining the effectiveness of treatment methods in reducing pollution scales is made easier by analysing waste discharge concentrations.The waste discharge concentration analysis is useful for assessing how effectively wastewater treatment techniques reduce pollution levels.This study aims to explore the Casson micropolar fluid flow through two parallel plates with the influence of pollutant concentration and thermophoretic particle deposition.To explore the mass and heat transport features,thermophoretic particle deposition and thermal radiation are considered.The governing equations are transformed into ordinary differential equations with the help of suitable similarity transformations.The Runge-Kutta-Fehlberg’s fourthfifth order technique and shooting procedure are used to solve the reduced set of equations and boundary conditions.The integration of a neural network model based on the Levenberg-Marquardt algorithm serves to improve the accuracy of predictions and optimize the analysis of parameters.Graphical outcomes are displayed to analyze the characteristics of the relevant dimensionless parameters in the current problem.Results reveal that concentration upsurges as the micropolar parameter increases.The concentration reduces with an upsurge in the thermophoretic parameter.An upsurge in the external pollutant source variation and the local pollutant external source parameters enhances mass transport.The surface drag force declines for improved values of porosity and micropolar parameters.

Behaviors of vanadium and chromium in coal-based direct reduction of high-chromium vanadium-bearing titanomagnetite concentrates followed by magnetic separation

The reduction behaviors of FeO·V2O3 and FeO·Cr2O3 during coal-based direct reduction have a decisive impact on the efficient utilization of high-chromium vanadium-bearing titanomagnetite concentrates. The effects of molar ratio of C to Fe n(C)/n(Fe) and temperature on the behaviors of vanadium and chromium during direct reduction and magnetic separation were investigated. The reduced samples were characterized by X-ray diffraction(XRD), scanning election microscopy(SEM) and energy dispersive spectrometry(EDS) techniques. Experimental results indicate that the recoveries of vanadium and chromium rapidly increase from 10.0% and 9.6% to 45.3% and 74.3%, respectively, as the n(C)/n(Fe) increases from 0.8 to 1.4. At n(C)/n(Fe) of 0.8, the recoveries of vanadium and chromium are always lower than 10.0% in the whole temperature range of 1100-1250 °C. However, at n(C)/n(Fe) of 1.2, the recoveries of vanadium and chromium considerably increase from 17.8% and 33.8% to 42.4% and 76.0%, respectively, as the temperature increases from 1100 °C to 1250 °C. At n(C)/n(Fe) lower than 0.8, most of the FeO·V2O3 and FeO·Cr2O3 are not reduced to carbides because of the lack of carbonaceous reductants, and the temperature has little effect on the reduction behaviors of FeO·V2O3 and FeO·Cr2O3, resulting in very low recoveries of vanadium and chromium during magnetic separation. However, at higher n(C)/n(Fe), the reduction rates of FeO·V2O3 and FeO·Cr2O3 increase significatly because of the excess amount of carbonaceous reductants. Moreover, higher temperatures largely induce the reduction of FeO·V2O3 and FeO·Cr2O3 to carbides. The newly formed carbides are then dissolved in the γ(FCC) phase, and recovered accompanied with the metallic iron during magnetic separation.

Novel two-step process to improve efficiency of bio-oxidation of Axi high-sulfur refractory gold concentrates

In order to improve the bio-oxidation efficiency of Axi refractory gold concentrate, a two-step process including a high temperature chemical oxidation and a subsequent bio-oxidation, combined with p H control during the bio-oxidation step was used. The results revealed that the optimum mode was to maintain solution p H at 1.0-1.2 during the biological oxidation stage. Under this condition, the activity of mixed culture could be sustained and the formation of jarosite could be diminished, thus the oxidation efficiency was improved. The oxidation levels of iron and sulfur were improved by 12.50% and 15.49%, and the gold recovery was increased by 21.02%. Therefore, the two-step process combined with p H control is an effective method for oxidizing the biohydrometallurgical process of Axi gold concentrate, and it will have a broad prospect of application in dealing with complex refractory gold concentrate.

Apparent activation energy for spontaneous combustion of sulfide concentrates in storage yard

In order to evaluate the spontaneous combustion hazard of sulfide concentrates in storage, three different kinds of sulfide concentrates （sulfur-rich sulfide concentrate, iron sulfide concentrate and copper sulfide concentrate） were obtained from a storage yard in Dongguashan Copper Mine, China. The reaction processes at different heating rates of 5, 10, 15, 20, and 25 ℃/min in air flow from ambient temperature to 1 000 ℃ were studied by TG-DTG-DSC analysis. By the peak temperatures of DTG curves, the whole reaction process for each sample was divided into different stages, and the corresponding apparent activation energies were calculated by the Ozawa-Flynn-Wall method. It is found that the reaction process of each sample is considerably complex; the apparent activation energy values change from 36 to 160 kJ/mol in different temperature ranges; sulfur-rich sulfide and iron sulfide concentrates have lower apparent activation energy than copper sulfide concentrate below 150 ℃; so they are more inclined to cause spontaneous combustion at ambient temperature.

CAUSTIC DECOMPOSITION OF SCHEELITE AND SCHEELITE－WOLFRAMITE CONCENTRATES THROUGH MECHANICAL ACTIVATION

Based on physicochemical study of the reaction between scheelite and NaOH, a new decomposition process for scheelite and scheelitewolframite concentrate, i. e., mechenically activating caustic decomposition has been developed, and it has been successfu

Efficient ozonation of reverse osmosis concentrates from petroleum refinery wastewater using composite metal oxideloaded alumina

Novel Mn–Fe–Mg-and Mn–Fe–Ce-loaded alumina（Mn–Fe–Mg/Al2O3 and Mn–Fe–Ce/Al2O3） were developed to catalytically ozonate reverse osmosis concentrates generated from petroleum refinery wastewaters（PRW-ROC）. Highly dispersed 100–300-nm deposits of composite multivalent metal oxides of Mn（Mn^2＋）, Mn^3＋,and Mn^4＋, Fe（Fe^2＋）and Fe^3＋ and Mg（Mg^2＋）, or Ce（Ce^4＋） were achieved on Al2O3 supports. The developed Mn–Fe–Mg/Al2O3 and Mn–Fe–Ce/Al2O3 exhibited higher catalytic activity during the ozonation of PRW-ROC than Mn–Fe/Al2O3, Mn/Al2O-3, Fe/Al2O3, and Al2O3. Chemical oxygen demand removal by Mn–Fe–Mg/Al2O3-or Mn–Fe–Ce/Al2O3-catalyzed ozonation increased by 23.9% and23.2%, respectively, in comparison with single ozonation.Mn–Fe–Mg/Al2O3 and Mn–Fe–Ce/Al2O3 notably promoted áOH generation and áOH-mediated oxidation. This study demonstrated the potential use of composite metal oxide-loaded Al2O3 in advanced treatment of bio-recalcitrant wastewaters.

Pretreatment and thiosulfate leaching of refractory gold-bearing arsenosulfide concentrates

A hydrometallurgical process for refractory gold-bearing arsenosulfide concentrates at ambient temperature and pressure was presented, including fine grinding with intensified alkali-leaching （FGIAL）, enhanced agitation alkali-leaching （EAAL）, thiosulfate leaching and displacement. Experimental results on a refractory gold concentrate showed that the total consumption of NaOH in alkaline leaching is only 41% of those theoretically calculated under the conditions of full oxidization for the same amount of arse- nides and sulfides transformed into arsenates and sulfates, and 72.3% of gold is synchro-dissoluted by thiosulfate self-generated during alkaline leaching. After alkaline leaching, thiosulfate leaching was carried out for 24 h. The dissolution of gold is increased to 91.9% from 4.6% by cyanide without the pretreatment. The displacement of gold by zinc powder in the solution gets to 99.2%. Due to an amount of thiosulfate self-generated during alkaline leaching, the reagent addition in thiosulfate leaching afterwards is lower than the normal.

Dielectric Characterization and Microwave Roasting of Molybdenite Concentrates at 915 MHz Frequency

The magnetic hysteresis loop was measured to know the magnetic property of molybdenite concentrate.In order to evaluate its microwave absorption capacity, the dielectric properties of molybdenite concentrate was investigated using cavity perturbation method at 915 MHz dependent on densities and temperatures.The parameter data were fitted using regression fit and a model related to the same density and temperature ranges was developed.A nonlinear surface fitting was used to present visually the effect of dielectric parameters on the microwave penetrate depth of molybdnite concentrate.The crystal products of MoO 3 obtained from microwave roasting at different temperatures were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD).The results show both the dielectric constants and loss factors increase in the increase of apparent densities and temperatures with different growth rates in the experimental range.Due to the distinguished trend of dielectric performance dependent on temperatures, two parts in the heating scenario for the molybdenite concentrate samples were divided.The microwave penetration depth is inversely proportional to both apparent densities and temperatures.The nonlinear fitting surfaces indicate the increase of dielectric loss provides an enough decrease in microwave penetration depth.In contrast, the dielectric constant has a positive effect for it.Pure MoO 3 was produced at 800 ℃ by using microwave energy.This work can be helpful to design and simulate microwave system for efficient beneficiation of molybdenite concentrate and to prepare molybdenum products from this concentrate.

Selective leaching of vanadium from V-Ti magnetite concentrates by pellet calcification roasting-H_(2)SO_(4) leaching process

A novel method of pellet calcification roasting-H_(2)SO_(4) leaching was proposed to efficiently separate and extract vanadium(V)from vanadium-titanium(V-Ti)magnetite concentrates.The leaching rate of V is as high as 88.98%,while the leaching rate of impurity iron is only 1.79%.Moreover,the leached pellets can be used as raw materials for blast furnace ironmaking after secondary roasting.X-ray photoelectron spectroscopy(XPS)and scanning electron microscopy with energy dispersive X-ray spectrometry(SEMEDS)analyses showed that V^(3+)was oxidized to V^(5+)after roasting at 1200℃,and V^(5+)was then leached by H_(2)SO_(4).X-ray diffraction(XRD)analyses and single factor experiment revealed a minimal amount of dissolved Fe_(2)O_(3) during H_(2)SO_(4) leaching.Therefore,a high separation degree of V and iron(Fe)from V-Ti magnetite concentrate was achieved through H_(2)SO_(4) leaching.Compared with the traditional roastingleaching process,this process can achieve a high selectivity of V and Fe,and has excellent prospects for industrial production.

A new extraction process of refractory gold arsenosulfide concentrates

A new hydrometallurgical process for the refractory gold arsenosulfideconcentrates under normal temperature and pressure was presented. The experimental results of arefractory gold concentrate show that the total consumption of NaOH in alkaline leaching is only 40%of those theoretically calculated under the conditions of full oxidization at the same oxidation ofarsenic to ar-senate and sulfur to sulfate. After alkaline leaching, cyanidation and adsorptionwere carried out for 24 h. The dissolution of gold by NaCN is increased to 95.3% from 12.8% beforepretreatment, and meanwhile 99.3% of the adsorption of gold by activated charcoal. The consumptionof NaCN for one ton ore is 10 kg, which is 1.2 times less than that before pretreatment. As it iscarried out under normal temperature and pressure, the investment of installations is alsodecreased.

Differences of cyanide leaching between calcine and dust from refractory gold concentrates

Differences of cyanide leaching between the calcine and the dust from a refractory gold concentrate were investigated by comparative method. Results showed that gold leaching efficiencies of the calcine and the dust were 85.31% and 54.30%, respectively, with direct cyanidation. Contents and existing forms of arsenic and carbon were the main reasons for those differences. The maximum gold leaching efficiencies of the calcine and the dust were 87.70% and 58.60%, respectively, with cyanidation after NaOH pre-leaching. Harmful elements removal, gold loss in NaOH pre-leaching and iron oxides hindrance codetermined gold leaching efficiencies of the calcine and the dust. After H2SO4 pre-leaching, the maximum gold leaching efficiencies of the calcine and the dust achieved 94.96% and 80.40%, respectively. The effect of carbonaceous matter was the main reason for differences for leaching efficiencies of the calcine and the dust. Based on those differences, two proper gold extraction processes were put forward, and gold leaching efficiencies for the calcine and the dust achieved 94.91% and 91.90%, respectively.

Direct carbothermic reduction of ilmenite concentrates by adding high dosage of Na_(2)CO_(3) in microwave field

A clean and efficient route for the utilization of ilmenite concentrates was proposed by direct carbothermic reduction in microwave field.High dosage of Na_(2)CO_(3),which can be recycled,was added to accelerate the reduction reaction of ilmenite concentrates.After microwave heating in the temperature range of 1073−1123 K for 20 min,the main products were Na_(2)TiO_(3) and metallic Fe with the metallization ratios being as high as 92.67%−93.21%.The reduction products were processed by water leaching,ball-milling in CO2 atmosphere and magnetic separation in turn.The final products after magnetic separation were Fe-rich materials and Ti-rich materials(90.04 wt.%TiO2),which can be used to produce iron and TiCl4 or TiO2.The optimized heating temperature was 1123 K in terms of metallization ratios,magnetic separation and caking property of the reduction products.Besides,the reduction mechanism of ilmenite concentrates with the addition of Na_(2)CO_(3) in microwave field was also proposed.

Mineralogical characterization and pretreatment for antimony extraction by ozone of antimony-bearing refractory gold concentrates

The mineralogical characterization of antimony-bearing refractory gold concentrates and the antimony extraction by ozonein HCl solution were investigated.The mineralogical study shows that there exist stibnite(Sb2S3),arsenopyrite(FeAsS),pyrite(FeS2)and quartz in the concentrates,and the gold is mainly(67.42%)encapsulated in sulfides.The antimony extraction by ozone inhydrochloric acid was employed and the influences of temperature,liquid/solid ratio,HCl concentration and stirring speed on theextraction of antimony were investigated.High antimony extraction(93.75%)is achieved under the optimized conditions.After thepretreatment by ozone,the antimony is recovered efficiently and the gold is enriched in the leaching residue.

Influence of Ferric and Ferrous Iron on Chemical and Bacterial Leaching of Copper Flotation Concentrates

The effects of ferrous and ferric iron as well as redox potential on copper and iron extraction from the copper flotation concentrate of Sarcheshmeh, Kerman, Iran, were evaluated using shake flask leaching examinations. Experiments were carried out in the presence and absence of a mixed culture of moderately thermophile microorganisms at 50?C. Chemical leaching experiments were performed in the absence and presence of 0.15 M iron (ferric added medium, ferrous added medium and a mixture medium regulated at 420 mV, Pt. vs. Ag/AgCl). In addition, bioleaching experiments were carried out in the presence and absence of 0.1 M iron (ferric and ferrous added mediua) at pulp density 10% (w/v), inoculated bacteria 20% (v/v), initial pH 1.6, nutrient medium Norris and yeast extract addition 0.02% (w/w). Abiotic leaching tests showed that the addition of iron at low solution redox potentials significantly increased the rate and extent of copper dissolution but when ferric iron was added, despite a higher initial rate of copper dissolution, leaching process stopped. Addition of both ferrous and ferric iron to the bioleaching medium levelled off the copper extraction and had an inhibitory effect which decreased the final redox potential. The monitoring of ferrous iron, ferric iron and copper extraction in leach solutions gave helpful results to understand the behaviour of iron cations during chemical and bacterial leaching processes.

Interaction mechanism between carboxylmethyl cellulose and iron ore concentrates in iron ore agglomeration

Carboxylmethyl cellulose(CMC) has become a commercial organic binder in agglomeration of iron ore concentrates. The relative molecular mass and degree of substitution(DS) of CMC have a large impact on its binding performance. The interaction mechanism between CMC and iron ore particles was analyzed through Zeta potential measurements, adsorption measurements and infrared spectra. The results show that the interaction is chemical adsorption-oriented and the CMC's adsorption performance is related to the properties of CMC as well as the type of iron oxides. CMC has a greater affinity to Fe2O3 than Fe3O4, and CMC with higher relative molecular mass shows a higher adsorption isotherm. Pelletization of practical iron ore concentrates added with CMC further illustrates that CMC with higher relative molecular mass or DS exhibits a better binding performance, which is consistent with the results of adsorption tests.

Thermal Decomposition of Pyrite, Arsenopyrite and Auriferous Concentrates in the Presence of Sodium Hydroxide

The thermal decomposition of pyrite, arsenopyrite and auriferous concentrates in the presence of sodium hydroxide was studied by using TG DTA and XRD methods. For the arsenopyrite mineral the reaction takes place at 200～350℃ with the formation of Na 2SO 4, Na 3AsO 4, FeSO 4, Fe 8As 10 O 23 and FeAs, and a large amount of FeAsS do not decompose at this temperature. When the temperature arrives at 800℃, the exothermic reaction takes place with the formation of Na 3AsO 4, Na 2SO 4, Fe 2O 3 and a little amount of As 4S 3. For the pyrite mineral the reaction takes place between 200～350℃ with the formation of Fe 2(SO 4) 3, Fe 3S 4, FeS, Na 2Fe(SO 4) 2 in addition to unreacted FeS 2 and NaOH. When the temperature arrives at 800℃, almost all the pyrite decomposes and the Fe 2O 3, Na 2SO 4, Fe(SO 4) 3 and a minor amount of Fe 1- x S are produced. The decomposition temperatures of arsenopyrite and pyrite get lower as their particle sizes are small. The results also indicated that with the addition of an appropriate amount of NaOH, nearly complete containment of arsenic and sulphur during the decomposition of auriferous concentrate may be possible.

Consolidation mechanism of gold concentrates containing sulfur and carbon during oxygen-enriched air roasting

Consolidation in calcines is a common problem in the oxygen-enriched air roasting of refractory gold concentrates containing sulfur and carbon when the initial temperature is greater than 600°C. To determine the phases that caused consolidation, gold concentrates were roasted under different conditions and the calcines were mainly detected by X-ray diffraction (XRD). The possible underlying mechanism was then studied through comparisons of the XRD patterns of different calcines. The results indicated that the generation of calcium magnesium silicate, iron-doped calcium aluminosilicate, and calcium aluminate caused the consolidation. Furthermore, an enriched oxygen atmosphere accelerated the oxidation reaction and the emitted heat increased the local temperature in calcines. The local temperature was inferred to have increased to the generation temperature zone of the corresponding liquid phases. Oxidation of the pyrite and decomposition of the dolomite and muscovite mainly occurred at the initial stage of oxygen-enriched air roasting. Calcium was confirmed to be essential to the consolidation process. © 2017, University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg.

A Facile Li_(2)TiO_(3) Surface Modification to Improve the Structure Stability and Electrochemical Performance of Full Concentration Gradient Li-Rich Oxides

Full concentration gradient lithium-rich layered oxides are catching lots of interest as the next generation cathode for lithium-ion batteries due to their high discharge voltage,reduced voltage decay and enhanced rate performance,whereas the high lithium residues on its surface impairs the structure stability and long-term cycle performance.Herein,a facile multifunctional surface modification method is implemented to eliminate surface lithium residues of full concentration gradient lithium-rich layered oxides by a wet chemistry reaction with tetrabutyl titanate and the post-annealing process.It realizes not only a stable Li_(2)TiO_(3)coating layer with 3D diffusion channels for fast Li^(+)ions transfer,but also dopes partial Ti^(4+)ions into the sub-surface region of full concentration gradient lithium-rich layered oxides to further strengthen its crystal structure.Consequently,the modified full concentration gradient lithium-rich layered oxides exhibit improved structure stability,elevated thermal stability with decomposition temperature from 289.57℃to 321.72℃,and enhanced cycle performance(205.1 mAh g^(-1)after 150 cycles)with slowed voltage drop(1.67 mV per cycle).This work proposes a facile and integrated modification method to enhance the comprehensive performance of full concentration gradient lithium-rich layered oxides,which can facilitate its practical application for developing higher energy density lithium-ion batteries.