Photogenerated-hole scavenger for enhancing photocatalytic chalcopyrite bioleaching

The effects of photogenerated-hole scavengers(ascorbic acid,oxalic acid,humic acid and citric acid)on chalcopyrite bioleaching in the presence of visible light were studied using Acidithiobacillus ferrooxidans(A.ferrooxidans).Four sets of bioleaching experiments were performed:(1)visible light+0 g/L scavenger,(2)visible light+0.1 g/L of different scavenger(ascorbic acid,oxalic acid,humic acid and citric acid),(3)dark+0.1 g/L of different scavenger(ascorbic acid,oxalic acid,humic acid and citric acid),and(4)dark+0 g/L scavenger(control group).The results showed that ascorbic acid and oxalic acid could act as photogenerated-hole scavengers and significantly enhance chalcopyrite bioleaching under visible light.The dissolved copper in the light group without scavenger was only 18.7%higher than that of the control group.The copper extraction rates of the light groups with oxalic acid and ascorbic acid were respectively 30.1%and 32.5%higher than those of the control group.Scanning electron microscopy(SEM),X-ray diffraction(XRD)and Fourier transform infrared spectroscopy(FT-IR)analyses indicated that ascorbic acid and oxalic acid as photogenerated-hole scavenger could capture photo-generated holes and inhibit jarosite formation on the chalcopyrite surface,thereby enhancing bioleaching of chalcopyrite under visible light.

Element analysis method of concealed explosive based on TNA

The detection technology of concealed bulk explosives is related to social security and national defense construction and has important research significance. In this paper, an element analysis method of concealed explosives based on thermal neutron analysis is proposed.This method could provide better reconstruction precision for hydrogen, carbon, and nitrogen ratios, making it possible to discriminate explosives from other compounds with the same elements but different proportions, as well as to identify the types of concealed bulk explosives. In this paper, the basic principles and mathematical model of this method are first introduced, and the calculation formula of the element number ratio(the ratio between the nucleus numbers of two different elements) of the concealed explosive is deduced. Second, a numerical simulation platform of this method was established based on the Monte Carlo JMCT code. By calibrating the absorption efficiencies of the explosive device to c rays, the element number ratios of a concealed explosive model under the irradiation of thermal neutrons were reconstructed from the neutron capture prompt c-ray spectrum. The reconstruction values were in good agreement with the actual values,which shows that this method has a high reconstruction precision of the element number ratio for concealed explosives. Lastly, it was demonstrated using the simulation study that this method can discriminate explosives,drugs, and common materials, with the capability of determining the existence of concealed bulk explosives and identifying explosive types.

Study of spatial resolution of the associated alpha particle imaging–time-of-flight method

Associated alpha particle imaging based on the time-of-flight(API-TOF) technique is an advanced neutron analysis method, which is capable of discriminating material nuclides and three-dimensional imaging of the spatial distribution of material nuclei. In this paper, the spatial resolution of API-TOF and its effects are studied using mathematical analysis and Monte Carlo numerical simulation. The results can provide guidance and assist in designing of API-TOF detection devices. First, a mathematical analysis of the imaging principles of the API-TOF was carried out, and the calculation formulas of the spatial resolution of API-TOF were deduced. Next, the relationship between the device layout and the spatial resolution of the API-TOF detection device was studied. The concept of a typical API-TOF detection device with an optimized structure was proposed. Then, the spatial distribution of the spatial resolution of the typical API-TOF detection device was analyzed, and the effects of the time resolution and the neutron emission angle resolution on the spatial resolution were studied. The results show that spatial resolutions better than 1 cm can be achieved by improving the time resolution and the neutron emission angle resolution to appropriate levels. Finally, a Monte Carlo numerical simulation program was developed for the study of the APITOF and was used to calculate the spatial resolutions of the API-TOF. The comparison of the results shows that thespatial resolutions calculated based on the Monte Carlo numerical simulation are in good agreement with those calculated based on the mathematical analysis. This verifies the mathematical analysis and the evaluation of the effects of the spatial resolution of the API-TOF in this study.

Acidithiobacillus ferrooxidans enhanced heavy metals immobilization efficiency in acidic aqueous system through bio-mediated coprecipitation

This study investigated the promotion effect of A.ferrooxidans on complex heavy metals coprecipitation process.A.ferrooxidans significantly enhanced the ferrous oxidation,which also promoted the formation of iron-oxyhydroxysulphate.Cu(II)concentration reduced to0.058mmol/L in A.ferrooxidans inoculated system,and Cd also reduced to the lowest concentration(0.085mmol/L).Pb was mainly immobilized as anglesite and iron-oxyhydroxysulphate promoted the removal of remanent Pb in solution.The precipitates are characterized by XRD,SEM,and FTIR analysis.The main component of the iron-oxyhydroxysulphate was well crystallized jarosite.A.ferrooxidans contributed to the formation of schwertmannite in later monovalent cation lack stage.Higher ferrous iron oxidation rate and Fe(III)supply rate in A.ferrooxidans inoculated system facilitated polyhedron crystal formation and the increase of particle diameter.Complex heavy metals could be incorporated into iron oxyhydroxysulphate crystal,and efficiently removed from acidic wastewater through A.ferrooxidans mediated coprecipitation.

High ratio of illegitimate visitation by small bees severely weakens the potential function of heteranthery

Aims in heterantherous plants,‘division of labor’among structurally dif-ferent stamens,i.e.pollinating and feeding functions,has been thought to reduce the evolutionary conflict of relying on pollen both as the carrier of male gametes and as the food for pollinators.The key to successful division of labor among different sets of stamens is the size match between stamens and legitimate pollinators,which results in the precise deposition of pollen onto specific locations on pollinator’s body and facilitates cross pollination.However,the potential impact of small illegitimate insects that are ubiquitous dur-ing the pollination process on the plant reproduction in heteranth-erous species has been largely neglected in previous studies and never been demonstrated experimentally.Methods Here,we investigated the functions of three different types of sta-mens in Commelina communis.The pollinator visitation,pollen removal and deposition were compared among flowers with dif-ferent types of anthers emasculated at two natural populations.moreover,the mating systems of C.communis in wild populations were estimated using microsatellite markers.Important Findingsour data showed that the main floral visitors for C.communis at the two studied populations were small illegitimate bees rather than legitimate pollinators,accounting for 77.5 and 92.2%of total flower visits,respectively.Flower manipulations in C.communis demon-strated that the two types of brightly yellow stamens separately func-tioned as‘deceptive attraction’and‘feeding’functions.although the brown inconspicuous stamens of C.communis with the largest amount of fertile pollen had the potential function in offering pollen for cross pollination,the high ratio of illegitimate visitation by small bees significantly affected the dispersal and deposition of pollen from the pollinating anthers,and subsequently decreased the levels of outcrossing(tm=0.23-0.32)in wild populations.our work further confirmed that the size match between pollinators and the floral morphology is the prerequisite to successfully fulfill the functional differentiation among different sets of stamens in heterantherous plants.local high ratio of illegitimate visitation by size unmatched insects could significantly weaken the potential functions of heteranthery,affecting the dispersal and deposition of functional pollen in heterantherous plants and further the whole mating systems.

A rare case of type 1 leprosy reactions following tetanus infection in a borderline tuberculoid leprosy patient and a literature review

Background:Type 1 leprosy reaction,also known as“reversal reaction”,is related to cellular immune responses to Mycobacterium leprae antigens.The risk factors that trigger type 1 leprosy reactions are poorly understood.Leprosy with concurrent tetanus is rare,and there are no publicly available reports of a leprosy patient infected with tetanus that induced type 1 leprosy reactions.Case presentation:A 56-year-old Chinese Han female presented to our hospital with symptoms of erythematous plaques and pain over her left upper limb for 2 days and foreign object sensation in her throat for 3 days.The patient had a 6-year history of leprosy.Type 1 leprosy reactions were initially considered,followed by treatment with methylprednisolone.Two days later,the patient’s symptoms were aggravated,with neck muscle tension and difficulty in opening her mouth,and the erythematous plaques had spread over most of her left upper limb.After further careful examinations,we confirmed the diagnosis of tetanus with concurrent type 1 leprosy reactions.The patient was given anti-tetanus treatment for 12 days and anti-leprosy reaction treatment for 4 months;the diseases were eventually controlled.Conclusions:This report suggests that tetanus infection may be a trigger for type 1 leprosy reactions.