Biodegradable calcium sulfide-based nanomodulators for H_(2)S-boosted Ca^(2+)-involved synergistic cascade cancer therapy

Hydrogen sulfide(H_(2)S)is the most recently discovered gasotransmitter molecule that activates multiple intracellular signaling pathways and exerts concentration-dependent antitumor effect by interfering with mitochondrial respiration and inhibiting cellular ATP generation.Inspired by the fact that H_(2)S can also serve as a promoter for intracellular Ca^(2+)influx,tumor-specific nanomodulators(I-CaS@PP)have been constructed by encapsulating calcium sulfide(CaS)and indocyanine green(ICG)into methoxy poly(ethylene glycol)-b-poly(lactide-co-glycolide)(PLGA-PEG).I-CaS@PP can achieve tumor-specific biodegradability with high biocompatibility and pH-responsive H_(2)S release.The released H_(2)S can effectively suppress the catalase(CAT)activity and synergize with released Ca^(2+)to facilitate abnormal Ca^(2+)retention in cells,thus leading to mitochondria destruction and amplification of oxidative stress.Mitochondrial dysfunction further contributes to blocking ATP synthesis and downregulating heat shock proteins(HSPs)expression,which is beneficial to overcome the heat endurance of tumor cells and strengthen ICG-induced photothermal performance.Such a H_(2)S-boosted Ca^(2+)-involved tumor-specific therapy exhibits highly effective tumor inhibition effect with almost complete elimination within 14-day treatment,indicating the great prospect of CaS-based nanomodulators as antitumor therapeutics.

Manganese extraction by reduction-acid leaching from low-grade manganese oxide ores using CaS as reductant

The extraction of manganese from low-grade manganese oxide ores using Ca S derived from Ca SO4 as reductant was investigated. The effects of mass ratio of Ca S to ore, reduction temperature, reduction time, liquid to solid ratio（L/S ratio）, stirring speed, leaching temperature, leaching time and H2SO4 concentration on the leaching rates of Mn and Fe during the reduction–acid leaching process were discussed. The leaching rates of 96.47% for Mn and 19.24% for Fe were obtained under the optimized conditions of mass ratio of Ca S to manganese oxide ore 1：6.7, L/S ratio 5：1, stirring speed 300 r/min, reduction temperature of 95 °C for 2.0 h in the reduction process and leaching stirring speed of 200 r/min, H2SO4 concentration of 1.5 mol/L, leaching temperature of 80 °C for 5 min in the leaching process. In addition, this process can be employed in the recovery of manganese from various manganese oxide ores, and Mn leaching rate above 95% is obtained.

Phosphogypsum Pyrolysis by Adding Mineralization Agent:Process and Mechanism

In order to decrease energy consumption for phosphogypsum(PG)pyrolysis process,a pilot-scale vertical-retort furnace was designed initiatively,and then mineralization agent was added to pyrolysis mixture.Calcium fluoride(CaF_(2))was proven to be a suitable mineralization agent,and the optimal parameters were:pyrolysis temperature 960℃,carbon-sulfur mole ratio 0.7,reaction time 50 min,and CaF_(2)dosage 4%by weight.Under this condition,PG decomposition and sulfur dioxide(SO_(2))conversion were up to 89.6%and 67.3%,respectively.CaF_(2)could lead to the formation of fluosilicate complexes,and facilitate PG decomposition at a low temperature.During pyrolysis process,calcium sulfide(CaS)was an inevitable intermediate substance,and only a part of total sulfur in the feedstock could be converted to SO_(2).

Luminescence and ESR Studies of CaS：Dy Phosphor

CaS phosphor activated with Dy ions is prepared by the solid-state diffusion method. The phosphor is characterized by x-ray powder diffraction, thermogravimetric analysis and photoiuminescence. Defect centres formed in CaS：Dy are studied using the technique of electron spin resonance. The thermoluminescence glow curve shows peaks at around 117℃ and 345℃. Irradiated CaS：Dy exhibits ESR lines due to defect centres. The thermal annealing behaviour of one of the defect centres appears to correlate with the TL peaks at 117℃ and 345℃. This centre is characterized by an isotropic g-value of 2.0035 and is assigned to an F^＋ centre.

Microwave-promoted pure host phase for red emission CaS:Eu^(2+) phosphor from single CaSO_4 precursor and the photoluminescence property

We report a novel approach to obtaining a classical blue-green excitable CaS：Eu2＋ phosphor with desired red emission by microwave （MW） firing procedure in the absence of adding elemental sulphur. The disturbing effect of MW electro- magnetic field on decomposition of CaSO4 into CaS activated by europium is distinctly observed to give pure host phase without adding any elemental sulphur and carbon. The host phase evolution is observed to be highly dependent on the variation of applied MW power from X-ray diffraction （XRD） patterns and the corresponding photoluminescence （PL）, and a maximum PL intensity at 1100 W of MW power is acquired for the obtained purer host phase. The non-thermal and non-equilibrium effects by MW are revealed to correlate with the interaction between polar structure of the host and applied electromagnetic field. The results demonstrate an optional procedure to prepare this red-emitting phosphor in an effective, environment-friendly and scalable approach for phosphor production in the application of bio-illumination for plant cultivation and artificial photosynthesis.

Dissolution Modeling and Experimental Measurement of CaS-H20 Binary System

CaS formed during the retorting process of oil shale has a hazardous influence on surface water quality. Interaction of retorted oil shale with water generates highly alkaline leachate with a high content of sulfur due to the CaS component. A theoretical model describing the behavior of solid calcium sulfide in contact with water was developed. The model was consistent with the measurements showing change in dissolution behavior when solid CaS remained in the solution. Experimental measurements of pH and concentrations of ions were carried out in oxy- gen-free water at 25 ~C using CaS concentrations from 24.2-131.5 mgoL-1 （0.335--1.823 mmol/L）. Analysis of pH and concentrations of ions in the solution and calculations by the developed model showed that the solubility of CaS was estimated as 125.0 mg·L 1 （1.733 mmol/L）, and therefore the solubility product of CaS is 3.41×10^-10 （mo·L^-1）^2 at a temperature of 25℃.