Chemical Characterization of Auriferous Ores from the Brazilian State of Paraiba

One of the most important problems facing the gold industry is that the placer and free milling gold ores are almost terminating. Hence, the use of refractory ores has been increased during the recent years. In general, gold refractory ores occurs in various types of deposits associated with a range of minerals. Among the refractory ores, the sulfide type is the most common. The methodology employed in the mining process depends on the mode of occurrence of the ore and on the particle size, shape and degree of purity of the auriferous species. We have undertaken a mineralogical investigation of a representative sample of a complex gold mining ore collected in the municipality of Princesa Isabel, Paraiba, Brazil, using X-ray fluorescence spectrometry, X-ray diffractometry, infrared spectroscopy, inductively coupled plasma-atomic emission spectrometry and the Fire Assay. The results showed that the arsenic content of the ore was closely related to the gold content, and that the occurrence of “invisible gold” was associated primarily with pyrite and secondarily with arsenopyrite. The sulfur content of the ore was directly related to its refractoriness. It is concluded that gold mineralization in the study area is mainly of the gold-quartz-sulfide veins (lode gold), while the gold found in the mini-fractures of the deposits is probably associated with the hydrothermal processes that occurred in the region.

Comparative Study in Chemical Character and Fatty acidCompositions of Masked Civet's Fat and Nutria's Oil

The fat production rate in adult healthy masked civet(Paguma lavata) and nutria (Myocaster coypus) oil were measured. The values of iodine. saponification and acid PH, composition of fstty acids of grease were analyzed both chemically and by apparatus. The results showed that acid PH, iodine value, saponification value,and unsaturation point are 1.887 and 0.784, 53.90 and 48.32, 98.80 and 100.23. and 60.05% and 58.85% are respectively for masked civet's fat and nutria's oil. Both of masked civet's fat and nutria's oil contain a little of Eicosatetraenoic acid (C-20;4), which is of great significance in nutrition and metabolism for human body. The analysis results indicate that masked civet's oil is similar to nutria's oil in iodine value, saponification value and unsaturation point. Both masked civet's fat and nutria's oil are steady and have highly nutrition. They can be widely exploited and utilized in health protection and cosmetics made industry.

BASIC HYDROLYSIS OF ETHYL OXAL-ACETATE AND SOME CHEMICAL CHARACTERS OF 3-ETHOXY CAEBONYL PYRUVIC ACID

The products of basic hydrolysis of ethyl oxal-acetate and the preparation of 3-ethoxy carbonyl pyruvic acid 1 are reported.Esterification reaction of 1 with unhindered alcohols could be carried out smoothly, but it was unsuccessful with hindered alcohols.

Chemical characterization and source apportionment of PM_(1) and PM_(2.5) in Tianjin, China: Impacts of biomass burning and primary biogenic sources

The submicron particulate matter(PM_(1))and fine particulate matter(PM_(2.5))are very important due to their greater adverse impacts on the natural environment and human health.In this study,the daily PM_(1) and PM_(2.5) samples were collected during early summer 2018 at a sub-urban site in the urban-industrial port city of Tianjin,China.The collected samples were analyzed for the carbonaceous fractions,inorganic ions,elemental species,and specific marker sugar species.The chemical characterization of PM_(1) and PM_(2.5) was based on their concentrations,compositions,and characteristic ratios(PM_(1)/PM_(2.5),AE/CE,NO3^-/SO4^2-,OC/EC,SOC/OC,OM/TCA,K^+/EC,levoglucosan/K^+,V/Cu,and V/Ni).The average concentrations of PM_(1) and PM_(2.5) were 32.4μg/m and 53.3μg/m^3,and PM_(1) constituted 63%of PM_(2.5) on average.The source apportionment of PM_(1) and PM_(2.5) by positive matrix factorization(PMF)model indicated the main sources of secondary aerosols(25%and 34%),biomass burning(17%and 20%),traffic emission(20%and 14%),and coal combustion(17%and 14%).The biomass burning factor involved agricultural fertilization and waste incineration.The biomass burning and primary biogenic contributions were determined by specific marker sugar species.The anthropogenic sources(combustion,secondary particle formation,etc)contributed significantly to PM_(1) and PM_(2.5),and the natural sources were more evident in PM_(2.5).This work significantly contributes to the chemical characterization and source apportionment of PM_(1) and PM_(2.5) in near-port cities influenced by the diverse sources.

Comparative chemical characters of Sparganii Rhizoma from different regions in China

Objective： To compare the chemical characters of Sparganii Rhizoma from different areas via chromatographic analysis and to establish a sensitive LC/MS method for quality assessment of Sparganii Rhizoma.Methods： Under the optimised HPLC-PDA chromatographic conditions,twenty batches of Sparganii Rhizoma were analyzed by HPLC fingerprints.Principal component analysis（PCA）,orthogonal projections to latent structures discriminant analysis（OPLS-DA）and hierarchical cluster analysis（HCA）were performed based on all peak areas of Sparganii Rhizoma fingerprints.Meanwhile,part of common peaks were subsequently quantified by UFLC-QTRAP-MS.Results： The similarity values of HPLC fingerprints fluctuated in a wide range of 0.511–0.973,which showed variable differences of chemical characters among Sparganii Rhizoma from twenty habitats.PCA,OPLS-DA and HCA indicated that samples could be divided into five groups with different chemical characters,which generally corresponded with their geographical distributions.A total of 31 peaks in HPLC fingerprints were marked,and eight of them were identified and quantified.The quantitative result was generally in agreement with the classifications based on HPLC fingerprints,which indicated that Sparganii Rhizoma samples from eastern China mostly contained more contents including phenolic acids and flavonoids.Conclusion： This study not only proved that there were relationships between geographic distributions and internal chemical compositions of plants,which could provide evidence to the traditional Chinese medicine concept ＂geo-authentic＂,but also supplied a sensitive and rapid simultaneous quantitive method for the quality estimation of Sparganii Rhizoma.

Systematic chemical characterization of Xiexin decoctions using high performance liquid chromatography coupled with electrospray ionization mass spectrometry

Xiexin decoctions(XXDs)display beneficial anti-inflammatory and anti-diabetic effects,which raises interests on this group of formulae for broad clinical applications.However,there was no report about systematic analysis of XXDs to elucidate the constitution of chemical components,which hampers further investigations on the therapeutic values of XXDs.In this work,crude herbs were extracted and prepared to obtain the XXDs for systemic analysis on their chemical compositions,according to the information described in the ancient Zhang Zhongjing’s herbal formulae.LC-MS analysis of five XXDs was carried out to facilitate recognition of the source herbs for compounds in the mixture.A total number of 93 compounds were identified through our methods and their chemical classes encompassed five major groups,including protoberberine alkaloids,flavonoids,stilbenes,anthraquinones and saponins.Our current work provided important information about material basis for pharmacological studies on XXDs and would help shed light on relationships between chemical compositions and therapeutic effects.

Chemical characterization and source apportionment of atmospheric submicron particles on the western coast of Taiwan Strait, China

Taiwan Strait is a special channel for subtropical East Asian Monsoon and its western coast is an important economic zone in China. In this study, a suburban site in the city of Xiamen on the western coast of Taiwan Strait was selected for fine aerosol study to improve the understanding of air pollution sources in this region. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer（HR-To F-AMS） and an Aethalometer were deployed to measure fine aerosol composition with a time resolution of 5 min from May 1to 18, 2015. The average mass concentration of PM1 was 46.2 ± 26.3 μg/m^3 for the entire campaign. Organics（28.3%）, sulfate（24.9%）, and nitrate（20.6%） were the major components in the fine particles, followed by ammonium, black carbon（BC）, and chloride. Evolution of nitrate concentration and size distribution indicated that local NOx emissions played a key role in high fine particle pollution in Xiamen. In addition, organic nitrate was found to account for 9.0%–13.8% of the total measured nitrate. Positive Matrix Factorization（PMF）conducted with high-resolution organic mass spectra dataset differentiated the organic aerosol into three components, including a hydrocarbon-like organic aerosol（HOA） and two oxygenated organic aerosols（SV-OOA and LV-OOA）, which on average accounted for 27.6%,28.8%, and 43.6% of the total organic mass, respectively. The relationship between the mass concentration of submicron particle species and wind further confirmed that all major fine particle species were influenced by both strong local emissions in the southeastern area of Xiamen and regional transport through the Taiwan Strait.

Phosphogypsum:Part Ⅰ:Mineralogical,Thermogravimetric,Chemical and Infrared Characterization

Phosphogypsum (PG) derived from the dissolution of phosphate ore in H2SO4 has been characterized by using chemical and thermogravimetric analyses, X-ray difFraction and infrared spectrum to give an idea about the future utifization of this waste material. The PG under the investigation was free from the radioactive elements and Cd and contained about 141 × 10-6 rare earth elements in total, which favours the utilization of this material. PG was formed mainIy of gypsum, little anhydrite and quartz and rare kaolinite. It exhibited two large endothermic peaks corresponding to the dehydration of the sample and a small one which may be attributed to the Iiberation of the residual water that may be found in the soluble anhydrite. Also, an exothermic peak was observed which may be related to the transformation of soluble (γ-anhydrite) to insoluble β-anhydrite. PG exhibited the same absorption bands as that observed for chemical CaSO4.2H2O and natural gypsum samples besides the appearance of a weak band at 840 cm-1 which characterizes the vibration of H2PO4- group

A New Type of Multielements-Doped,Carbon-based Materials Characterized by High-thermoconductiv-ity,Low Chemical Sputtering,Low RES Yield and Exposure to Plasma

Low-Z materials, such as carbon-based materials and Be, are major plasma-facing material (PFM) for current, even in future fusion devices. In this paper, a new type of multielement-doped carbon-based materials developed are presented along with experimental re-sults of their properties. The results indicate a decrease in chemical sputtering yield by one order of magnitude, a decrease in both thermal shock resistance and radiation-enhanced sublimation, an evidently lower temperature desorption spectrum, and combined properties of exposing to plasma.

Reveal the pharmacodynamic substances and mechanism of an edible medicinal plant Rhodiola crenulate in DSS-induced colitis through plasma pharmacochemistry and metabolomics

Rhodiola crenulate is the edible medicinal herbal medicine widely used for altitude sickness in China.Interestingly,our previous work has found that R.crenulate extract(RCE)could significantly improve the pathology associated with dextran sulfate sodium-induced colitis.Thus,the current research aims to reveal the pharmacodynamic material basis of RCE,as well as its mechanism against colitis.The chemical characterization of RCE was performed by UHPLC-HR-MS,through which a total of 88 constituents were identified.Meanwhile,our results also found 29 constituents absorbed into blood and 8 metabolized absorbable compounds.The decreased flavonoids prototype and the elevated sulfated products of phenols were observed under pathophysiological conditions of colitis.The metabolomics study revealed that colitis caused the alternation of fatty acid metabolism,steroid hormone biosynthesis and bile acid metabolism.Correspondingly,RCE could prevent colitis by improving fatty acid metabolism and secondary bile acid metabolism.

Chemical composition and antioxidant capacity of the aqueous extract of Phellodendron amurense

The aqueous extract of Phellodendron amurense Rupr. （Amur Cork Tree） provides a rich source of antioxidants and chemical compounds, and can be used for food and wood preservative materials. In this study, we characterized the chemical composition of this extract by GC and GC/MS. The antioxidant capacity was evaluated using a variety of antioxidant assays （superoxide radical, hydroxyl radical, nitric oxide radical, and DPPH radical scavenging activity）. Additionally, total polyphenolic content was determined. Phenolic acids and acetone derivatives were major compounds of the extract capable of scavenging the DPPH free radical and reducing ferric ions. DPPH and ferric ion reduction results were strongly correlated with total phenolic content of the extract which also exhibited strong nitric oxide, hydroxyl radical scavenging and superoxide anion radical scavenging activities.

Structural and Chemical Characterization of the Ediacaran Embryo-Like Fossils via the Combination of 3D-XRM and FIB-SEM Approaches

The three-dimensional(3D)morphology,anatomy,and in-situ chemical composition analysis of fossils are crucial for systematic paleontology and determining their phylogenetic positions.Scanning electron microscopy(SEM)coupled with energy-dispersive X-ray spectroscopy(EDS),offers valuable structural and chemical information for the analysis of fossils.However,its primary limitation is the restriction to two-dimensional surface data,which limits the exploration of fossils’3D complexities.Conversely,3D X-ray microscopy(3D-XRM),also known as a novel form of micro-computed tomography(micro-CT)facilitates the non-destructive 3D reconstruction of fossil specimens.Nevertheless,it lacks the capability to provide in-situ compositional data.Acknowledging the constraints inherent in these individual techniques,and in response to the evolving requirements of paleontological research,this study introduces an integrated approach that combines 3D-XRM with EDS-coupled focused ion beam scanning electron microscopy(FIB-SEM).This innovative strategy is designed to synergize the advantages of both techniques,thereby addressing challenges that conventional methods cannot.It enables the rapid identification of regions of interest(ROI)within fossil specimens at micrometer resolution.Subsequently,this method collects detailed data on both 3D structures and chemical compositions at the nanometer scale for the identified ROI.This integrated approach represents a significant advancement in paleontological and geological research methodologies,promising to meet the increasing demands of these fields.

Contribution to the Study of Hot Water Scaling Phenomenon in the South of Touristic Area in Agadir City

This work aims to study the phenomenon of scaling observed in the hot water pipelines in the southern seaside touristic installations of Agadir city. This phenomenon has led to the formation of solid deposits and adherents to the internal walls of the facilities of the hot water. This deposit is at the origin of several technical, economic and environmental problems. It causes a decrease in the lifetime of boilers and a reduction of thermal exchanges and consequently a decrease in the energy efficiency of heating systems. In the present study, the samples of scale have been carried out at different points of hot water pipelines. The characterization of different scale samples recovered was conducted by X-ray fluorescence (XRF), elemental analysis (CHNS-O), infrared spectrometry (IR), thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Analytical results showed that scale samples collected on different sites in touristic hot water system are mostly formed by calcium carbonate. Thermodynamic conditions in the site were favourable to the aragonite variety formation.

Biologically active components for cosmeceutical use extracted from Chaetomorpha aerea

Background:The utilization of seaweed-based biologically active components in cosmeceutical formulations has been extensively rising due to skin health-promoting effects.Seaweeds have varieties of biologically active components and possess potential benefits in skincare products.Methods:Hence,the present study was done to characterize the bioactive constituents of green seaweed Chaetomorpha aerea by using the gas chromatography coupled with high-resolution mass spectrometry technique in ethanolic and methanolic extracts for presenting its cosmetic potential.Results:In analysis,a total of twenty-one different components were found in both the extracts.Their cosmetic potentials have been studied based on previous research studies.In addition,we characterized 9-octadecenoic acid[Z]-,phenylmethyl ester which belongs to benzyloxycarbonyls class.This compound exhibits promising applications in the cosmeceutical sector.This compound has a target peak percentage area(16.64%)with a retention time(39.1 min)in methanolic extract.Conclusion:The incorporation of seaweed-based bioactive components in cosmetics has been extensively growing due to its skin health-promoting effects.

Essential Oils of Lavandula stoechas subsp.luisieri as Antifungal Agent against Fungi from Strawberry Tree Fruit

L.stoechas subsp.luisieri is one of the five spontaneous species of the genus Lavandula that occurs spontaneously in Portugal.The chemical profile and antifungal activity of L.stoechas subsp.luisieri essential oils were investigated.The essential oil of two phenological stages was isolated by hydrodistillation and their chemical components analyzed by GC-FID/GC-MS.The minimum inhibitory concentration(MIC)and the minimum fungicidal concentration(MFC)of both essential oils were determinate to verify antifungal activity against different strains of fungi isolated from strawberry tree.The fungi tested were Aspergillus carbonarius,Rhizopus stolonifer,Penicillium brevicompactum,Aureobasidium pullulans and Saccothecium rubi.Essential oils were characterized by a high percentage of oxygenated monoterpenes(46-64%)such as trans-α-necrodyl acetate(12.58%),fenchone(5.97%),1,8-cineole(4.84%)and 5-methylene-2,3,4,4-tetramethylcyclopenten-2-enone(10.97%)were the major compounds in essential oil from dormancy stage,while the main compounds in flowering stage were trans-α-necrodyl acetate(26.90%),trans-α-necrodol(13.02%),lavandulyl acetate(6.53%)and linalool(5.82%).A strong antifungal activity of the essential oils was found against all strains,with MIC and MFC values ranged from 0.07-0.29μL/mL and 0.58-9.33μL/mL,respectively.

Production of Catecholate Siderophores by a Manglicolous fungus Emericella nidulans:A Novel Observation

Mangrove ecosystem is a rich source of manglicolous fungi.While much information is available on diversity of these fungi,their siderophores have not been explored yet.The present study was carried out with a view to explore siderophore production potential of manglicolous fungi along Ghogha Coast,Gulf of Khambhat,Gujarat,India.From four different mangrove samples viz.rhizosphere,rhizoplane,water and sediment,thirteen fungi belonging to Ascomycota were isolated,which were all siderophore producers.Their chemical characterization indicated siderophores of twelve fungi to be hydroxamates while one isolate Emericella nidulans exhibited a novel behaviour.Emericella nidulans a producer of both;hydroxamate and catecholate siderophore,a behaviour uncommon amongst fungi.The data revealed that exploring manglicolous fungi could reveal novelty in structural diversity of siderophore reflecting their unique ecological roles like avoiding siderophore piracy and oxidative stress for reclamation of mangrove associated coastal habitats.

Cost-effective integrated strategy for the fabrication of hard-magnet barium hexaferrite powders from low-grade barite ore

Ultrafine barium hexaferrite（BaFe12O19） powders were synthesized from the metallurgical extracts of low-grade Egyptian barite ore via a co-precipitation route. Hydrometallurgical treatment of barite ore was systematically studied to achieve the maximum dissolution efficiency of Fe（～99.7%） under the optimum conditions. The hexaferrite precursors were obtained by the co-precipitation of BaS produced by the reduction of barite ore with carbon at 1273 K and then dissolved in diluted HCl and FeCl3 solution at pH 10 using NaOH as a base; the product was then annealed at 1273 K in an open atmosphere. The effect of Fe^3＋/Ba^2＋ molar ratio and the addition of hydrogen peroxide（H2O2） on the phase structure, crystallite size, morphology, and magnetic properties were investigated by X-ray diffraction, scanning electron microscopy, and vibrating sample magnetometry. Single-phase BaFe（12）O（19） powder was obtained at an Fe^3＋/Ba^2＋ molar ratio of 8.00. The formed powders exhibited a hexagonal platelet-like structure. Good maximum magnetization（48.3 A×m^2×kg^–1） was achieved in the material prepared at an Fe^3＋/Ba^2＋ molar ratio of 8.0 in the presence of 5% H2O2 as an oxidizer and at 1273 K because of the formation of a uniform, hexagonal-shaped structure.

Chemical profiling of Huashi Baidu prescription, an effective anti-COVID-19 TCM formula, by UPLC-Q-TOF/MS

Huashi Baidu prescription(HSBDF),recommended in the Guideline for the Diagnosis and Treatment of Novel Coronavirus(2019-nCoV)Pneumonia(On Trials,the Seventh Edition),was clinically used to treat severe corona virus disease 2019(COVID-19)with cough,blood-stained sputum,inhibited defecation,red tongue etc.symptoms.This study was aimed to elucidate and profile the knowledge on its chemical constituents and the potential anti-inflammatory effect in vitro.In the study,the chemical constituents in extract of HSBDF were characterized by UPLC-Q-TOF/MS in both negative and positive modes,and the pro-inflammatory cytokines were measured by enzyme-linked immunosorbent assays(ELISA)to determine the effects of HSBDF in lipopolysaccharide(LPS)-stimulated RAW264.7 cells.The results showed that a total of 217 chemical constituents were tentativedly characterized in HSBDF.Moreover,HSBDF could alleviate the expression levels of IL-6 and TNF-αin the cell models,indicating that the antiviral effects of HSBDF might be associated with regulation of the inflammatory cytokines production in RAW264.7 cells.We hope that the results could be served as the basic data for further study of HSBDF on anti-COVID-19 effect.

Determination of microcapsule physicochemical, structural, and mechanical properties

Research into the fundamental properties of microcapsules and use of the results to develop a wide variety of products in industries such as printing, fast-moving consumer goods, construction, pharmaceuticals, and agrochemicals is a dynamic and ever-progressing field of study. For microcapsules to be effective in providing protection from harsh environments or delivering large payloads, it is essential to have a good understanding of their properties to enable quality control during formulation, storage, and applications. This review aims to outline the commonly used techniques for determining the physicochemical, struc- tural, and mechanical properties of microcapsules, and highlights the interlinked nature of these three areas with respect to the end-use industrial application. This review provides information on techniques that are well supported in the literature, and also examines microcapsule analytical techniques that will become more prevalent as a result of new technological developments or extensions from other areas of study.

Sintering effects on chemical and physical properties of bioactive ceramics

The objective of this study was to characterize the chemical and physical properties of bioactive ceramics prepared from an aqueous paste containing hydroxyapatite(HA)and beta tri-calcium phosphate(β-TCP).Prior to formulating the paste,HA andβ-TCP were calcined at 800℃and 975℃(11 h),milled,and blended into 15%/85%HA/β-TCP volume-mixed paste.Fabricated cylindrical rods were subsequently sintered to 900℃,1100℃or 1250℃.The sintered specimens were characterized by helium pycnometry,X-ray diffraction(XRD),Fourier transform-infrared(FT-IR),and inductively coupled plasma(ICP)spectroscopy for evaluation of porosity,crystalline phase,functional-groups,and Ca:P ratio,respectively.Mechanical properties were assessed via 3-point bending and diametral compression.Qualitative microstructural evaluation using scanning electron microscopy(SEM)showed larger pores and a broader pore size distribution(PSD)for materials sintered at 900℃and 1100℃,whereas the 1250℃samples showed more uniform PSD.Porosity quantification showed significantly higher porosity for materials sintered to 900℃and 1250℃(p<0.05).XRD indicated substantial deviations from the 15%/85%HA/β-TCP formulation following sintering where lower amounts of HA were observed when sintering temperature was increased.Mechanical testing demonstrated significant differences between calcination temperatures and different sintering regimes(p<0.05).Variation in chemical composition and mechanical properties of bioactive ceramics were direct consequences of calcination and sintering.