NIR-triggered thermo-responsive biodegradable hydrogel with combination of photothermal and thermodynamic therapy for hypoxic tumor

Hypoxia is a typical feature of solid tumors,which highly limits the application of the oxygen-dependent therapy.Also,the dense and hyperbaric tumor tissues impede the penetration of nanoparticles into the deep tumor.Thereby,we designed a novel localized injectable hydrogel combining the photothermal therapy(PTT)and the thermodynamic therapy(TDT),which is based on the generation of free radicals even in the absence of oxygen for hypoxic tumor therapy.In our study,gold nanorods(Au NRs)and 2,2-Azobis[2-(2-imidazalin-2-yl)propane]dihydrochlaride(AIPH)were incorporated into the hydrogel networks,which were formed by the copolymerization of hydrophobic N-isopropyl acrylamide(NIPAM)and hydrophilic glycidyl methacrylate modified hyaluronic acid(HAGMA)to fabricate an injectable and near-infrared(NIR)responsive hydrogel.The crosslinked in situ forming hydrogel could not only realize PTT upon the NIR laser irradiation,but also generate free radicals even in hypoxic condition.Meanwhile the shrink of hydrogels upon thermal could accelerate the generation of free radicals to further damage the tumors,achieving the controlled drug release on demand.The designed hydrogel with a sufficient loading capacity,excellent biocompatibility and negligible systemic toxicity could serve as a long-acting implant for NIR-triggered thermo-responsive free radical generation.The in vitro cytotoxicity result and the in vivo antitumor activity illustrated the excellent therapeutic effect of hydrogels even in the absence of oxygen.Therefore,this innovative oxygen-independent platform combining the antitumor effects of PTT and TDT would bring a new insight into hypoxic tumor therapy by the application of alkyl free radical.

Cloud removal of remote sensing image based on multi-output support vector regression

Removal of cloud cover on the satellite remote sensing image can effectively improve the availability of remote sensing images. For thin cloud cover, support vector value contourlet transform is used to achieve multi-scale decomposition of the area of thin cloud cover on remote sensing images. Through enhancing coefficients of high frequency and suppressing coefficients of low frequency, the thin cloud is removed. For thick cloud cover, if the areas of thick cloud cover on multi-source or multi-temporal remote sensing images do not overlap, the multi-output support vector regression learning method is used to remove this kind of thick clouds. If the thick cloud cover areas overlap, by using the multi-output learning of the surrounding areas to predict the surface features of the overlapped thick cloud cover areas, this kind of thick cloud is removed. Experimental results show that the proposed cloud removal method can effectively solve the problems of the cloud overlapping and radiation difference among multi-source images. The cloud removal image is clear and smooth.

Effects of Angelica Polysaccharide on telomere length in mice with benzene-induced aplastic anemia

Objective:To investigate the changes in telomere length and the level of burst-forming units-erythrocyte(BFU-Es)and colony-forming unit-erythrocytes(CFU-Es)in mice with benzene-induced aplastic anemia(AA),and follow-up the therapeutic effects of Angelica Polysaccharide(AP).Methods:Male BALB/c mice(n=120)were randomly divided into three groups(1,2,3):normal control(n=24),AA control(n=48),and treated AA(n=48),respectively.Mice in Group 2 received benzene inhalation for 2.5 months and 1 ml distilled water p.o.per day for 2 weeks after the establishment of AA models.Similar procedure was applied to the mice in Group 3 and AP was given for 2 weeks after the establishment of AA models.Real-time polymerase chain reaction was used to survey relative telomere length measurement of the bone marrow cells.A BFU-Es and CFU-Es survey was done to follow-up the therapeutic effects of AP.Results:Compared with normal control,significant reductions of RBC,WBC,and platelet counts were found in peripheral blood of AA mice.After treatment with AP,counts of BFU-Es and CFU-Es were restored up to 66.8%and 77.25%,respectively,and length of telomere was restored up to 76.34%,of the normal levels.The telomere length in treated AA group was higher than the control AA group.Conclusion:The AP can protect the telomere length and differentiation of hemopoietic stem/progenitor cells,accelerate the recovery of BFU-Es and CFU-Es of AA mice,and then improve the bone marrow failure.

Separation of aluminum from rare earth by solvent extraction with 4-octyloxybenzoic acid

Leaching method is usually used to extract rare earth(RE)elements from ion adsorbed RE ores.In the leaching process,some impurities such as aluminum(Al)enter the leaching solution.The separation of Al from RE by carboxylic acid extractant 4-octyloxybenzoic acid(POOA)was studied in this article.By changing the pH value,temperature,solvent,saponification degree and other parameters,the extraction and separation performance of POOA in chloride system was systematically studied.Through specific extraction experiments and slope analysis,it can be seen that the stoichiometric ratio of POOA to Al is 3:1during the extraction process.The separation factor of Al^(3+)and Pr^(3+)can reach about 160.00.Compared with easily emulsified naphthenic acid,POOA achieves better phase separation.The above results show that saponified POOA(S-POOA)has a good separation effect on Al and RE.Under the condition of low concentration stripping acid of 0.60 mol/L HCl,the developed extraction system can be almost completely stripped,and the stripping rate reaches 97.52%.The regenerated POOA can be directly used for the recycling extraction.

Selective recovery of Th(Ⅳ) from radioactive rare earth waste residue by utilizing MoS_(2)-modified ion-absorbed type rare earth tailings

In the process of extracting ion-absorbed rare earth ore(IREO),the production of radioactive waste is a major environmental concern.To address this issue,MoS_(2) was used to modify ion-absorbed rare earth tailings(RET) to synthesize a novel MoS_(2)@RET composite material for the effective handling of radioactive waste generated in IREO separation industry.The composite material was thoroughly characterized using various analytical techniques,including X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),thermogravimetry(TG),Fourier-transform infrared(FTIR),scanning electron microscopy(SEM),Brunaue r-Emmett-Teller(BET) and energy dispersive spectroscopy(EDS).By optimizing the operating parameters,the optimal experimental conditions were determined to be pH=3,contact time=60 min,liquid-solid ratio=6 g/L,and initial concentration=150 mg/L.The adsorption data fitted well with the pseudo second-order rate model.The thermodynamic parameters concerning the adsorption of Th(Ⅳ) were analyzed and computed.Langmuir isotherm model is a more fitting choice for the adsorption process compared to the Freundlich isotherm model.MoS_(2)@RET was used in the acid leachate of IREO waste residue,achieving the separation of Th and rare earth successfully.The mechanism of Th(Ⅳ) adsorption by MoS_(2)@RET was investigated,revealing that the adsorption process involves electrostatic interactions,chemical bonding,and redox reactions.The above research results indicate that MoS_(2)@RET composite materials have application potential in the sustainable treatment of IREO radioactive waste.

Precipitation transformation of rare earth sulfate into chloride with p-dodecylphenoxy carboxylic acids

Methods for transforming rare earth(RE)sulfate into chloride mainly include extraction process with organophosphonic mono-acids or aliphatic acids and precipitation process with ammonium bicarbonate(NH4 HCO3).In this paper,alkylphenoxy carboxylic acids(HAs)ofp-dodecylphenoxy acetic acid(HA-Ⅰ),pdodecylphenoxypropanoic acid(HA-Ⅱ)and p-dodecylphenoxybutyric acid(HA-Ⅲ),which were liquid at room temperature were synthesized and characterized.The precipitation mechanisms of RE elements with the HAs were investigated and the HA/RE molar ratios of the solid complexes were determined as3:1 by equi-molar series method which accord with the principle of charge balance.Applicability of HAs for the transformation of RE sulfate from concentrated sulfuric acid roasted RE concentrate into chloride via precipitation method was discussed.100%HA-Ⅱwas selected as the liquid organic precipitant without dilution of volatile solvent soracceleration of phase separation by phase-modifiers.The RE sulfate solution can be precipitated by HA-Ⅱafter neutralization with liquid NaOH and stripped with concentrated HCl at room temperature.High concentration of RE chloride of 218.1 g/L with low residue of sulfate radical of 0.536 g/L was obtained.The residual organic precipitant in the raffinate solution was tested to be lower than 8 mg/L at 25℃and the chemical oxygen demand(COD)in wastewater was less than 50 mg/L.

Preparation of high-purity neodymium chloride by solvent extraction in the mixer-settlers： A pilot-scale investigation

A novel purification process based on mixer-settlers for high-purity NdClwas developed. Acidic solution and pure NdClsolution were compared to scrub the less-extractable rare earths(REs)(La, Ce, and Pr)from loaded organic phase. The extractant with low-degree saponification was evaluated to remove the more-extractable element(Sm). Then the RE impurities(La, Ce, Pr, and Sm) in Nd were purified by an integrated process. Furthermore, effect of smuggling behavior on the purification of NdClin mixersettlers was studied. Based on the investigation mentioned above, the pilot-scale purification process for NdClwith a purity of 99.999% was developed, and the total recovery was about 99%.

Near-infrared light-activated cancer cell targeting and drug delivery with aptamer-modified nanostructures

Stimuli-activated targeted delivery systems for highly accurate treatment of tumors have received considerable attention in recent years. Herein, we reveal a light-activable cancer-targeting strategy that uses a complementary DNA sequence to hybridize and mask sgc8 aptamers conjugated onto photothermal agents such as gold nanorods or single-walled carbon nanotubes （SWNTs）. Upon exposure to near-infrared （NIR） laser, localized photothermal heating of the surface of those nano-agents results in dehybridization of the double-stranded DNA and uncaging of the aptamer sequence to allow specific cancer-cell targeting. Utilizing doxorubicin-loaded SWNTs as a model system, targeted drug delivery to cancer cells activated by NIR light was achieved. This work demonstrates the concept of NIR-activable tumor-targeting delivery systems with controllable cancer-cell binding to potentially enable highly specific and efficient cancer therapy.

Recovery of thorium and rare earths from leachate of ion-absorbed rare earth radioactive residues with N1923 and Cyanex■572

Ion-absorbed rare earth ores radioactive residues(IREORR)are a class of waste residue from the production of rare earth elements(REEs).Because of its radioactive dose,IREORR are usually stored in waste warehouses.IREORR are difficult to be disposed of.However,it contains relatively high concentrations of REEs,which can be considered as a valuable secondary resource.In this paper,a novel process is developed for the separation of thorium(Th)and recovery of REEs from IREORR hydrochloric acid leachate with primary amine N1923 and Cyanex?572,respectively.The effects of sulfate concentration,extractant concentration and pH on N1923 extraction in hydrochloric acid solution were investigated in detail.The results show that the extraction capacity of N1923 can be improved by adding sulfate to the solution and increasing the concentration of N1923.Acidity has little effect on the extraction of Th when pH is higher than 1.As for the stripping,REEs are more easily stripped from loaded organic phase than Th,and nitric acid is a better stripping agent than hydrochloric acid.Combined with the extraction of Cyanex■572 for REEs,a fractional extraction experiment for separating Th and enriching of REEs was performed.The yield of Th is higher than 99.9%and the concentration of REEs is enriched to 183.84 g/L.

Separation and recovery of rare earth from waste nickel-metal hydride batteries by phosphate based extraction-precipitation

A novel type of extraction-precipitation strategy based on phosphate was developed to recover rare earth(RE,i.e.,La,Ce,Nd,and Pr)from waste nickel-metal hydride(NiMH)batteries.This method does not require saponification and organic solvents.The novel phosphates,i.e.,dibenzyl phosphate(DBP),diphenyl phosphate(DPP),triphenyl phosphate(TPP)were studied as extraction-precipitants.DBP has high precipitation efficiencies for RE^(3+),which can reach 97.84%,100%,100%and 99.77%,respectively.In addition,the precipitation efficiencies of Mn^(2+),Co^(2+)and Ni^(2+)are less than 1.75%.DBP-RE has the largest particle size(D10=52.6μm,D50=135.35μm,D90=296.08μm),which is much larger than the precipitations formed by NH_(4)HCO_(3),H_(2)C2O_(4),CaO and MgO.The larger precipitation particle sizes contribute to improving the solid-liquid separation efficiency.With 3 mol/L hydrochloric acid,the stripping efficiency of DBP-RE reaches 98.60%,and the purity of recovered RE is 99.85%.The regenerated DBP can be directly used for the recycling extraction.Therefore,the novel extraction-precipitation strategy is a green and sustainable separation method.

Investigating the use of an ionic liquid for rare earth mineral flotation

Common collectors for rare earth mineral(REM) flotation,which include carboxylates and hydroxamates,face problems such as being non-selective and sensitive to impurity ions.A type of ionic liquid(IL),tetraethylammonium mono-(2-ethylhexyl)2-ethylhexyl phosphonate([N_(2222)][EHEHP]),has been investigated previously for rare earth elements(REE) solvent extraction,and was proven to be selective and effective.In this work,[N_(2222)][EHEHP] was evaluated as a collector in bastnasite(a primary REM source for REE production) flotation for the first time.The results were compared with quartz and hematite,two common gangue minerals in REM deposits.Zeta potential measurements and Fouriertransform infrared spectroscopy(FT-IR) were completed to investigate the surface chemical properties involved in the flotation of these minerals using this collector.The findings were compared with microflotation results.FT-IR and zeta potential measurements suggest adsorption of the collector’s phosphonate group onto bastnäsite and hematite,likely through chemisorption;whereas for quartz,the minimum micro flotation recovery is likely due to no adsorption of IL on its surface.Micro flotation re sults show higher collectability of [N_(2222)] [EHEHP] for hematite than bastnasite,the latter only shows appreciable recovery at pH 5 with elevated dosage of IL(500 g/t).To achieve better separation,a two-stage flotation scheme was designed and evaluated by bench scale flotation on a synthetic mineral mixture.The concentrates and tails were analyzed by magnetic separation,and it is found that bastnasite recovery over 90% with maximum upgrade ratio 1.7 can be achieved with elevated collector dosage.