检索结果-南通市图书馆

Towards the Recovery of By-Product Metals from Mine Wastes:An X-Ray Absorption Spectroscopy Study on the Binding State of Rhenium in debris from a Centennial Iberian Pyrite Belt Mine

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Minerals and Materials Characterization and Engineering 2014年第2期2卷 135-143页

作者： Maria-Ondina Figueiredo Teresa Pereira da Silva Joao Pedro Veiga daniel de oliveira Maria Joao batista CENIMAT/I3N Faculty of Sciences and TechnologyNew University of LisbonCampus da CaparicaLisbonPortugal Unit of Mineral Resources and Geophysics National Laboratory for Energy and GeologyAmadoraPortugal

Rhenium is a very scarce element, occurring in the Earth's crust mainly carried by molybdenite (MoS2). Due to a very low availability comparative to actual industrial demand, rhenium is nowadays one of the most expensive mineral commodities and an increased interest is focused on ex- ploring residues resulting from a long-term mining, particularly of sulphide ore deposits. It is therefore noteworthy to assign the presence of rhenium (in a concentration up to 3 ppm) in the waste materials from the old sulphur factory at the abandoned mine of Sao Domingos (Iberian Pyrite Belt, Southeast Portugal), exploited since the Roman occupation of Iberia. Aiming at a potential sustainable recovery of rhenium as a by-product, X-ray near-edge absorption spectroscopy (XANES) was applied to clarify the Re-binding and mode of occurrence by comparing Re L3-edge XANES spectra obtained from mine waste samples (previously fully characterized by X-ray laboratory techniques) with similar spectra collected from Re-rich molybdenites (Mo1-xRexS2) and from Re-O model compounds configuring various valences and coordination environments of rhenium ions. Obtained results are commented, ruling out a possible Re-S binding and rather conforming with the binding of rhenium to oxygen in the analysed mine waste materials.

关键词： Mine Waste Materials By-Products Iberian Pyrite Belt Rhenium XANES Re L_(3)-Edge

Molybdenite as a Rhenium Carrier:First Results of a Spectroscopic Approach Using Synchrotron Radiation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Minerals and Materials Characterization and Engineering 2013年第5期1卷 207-211页

作者： Teresa Pereira da Silva Maria-Ondina Figueiredo daniel de oliveira João Pedro Veiga Maria João batista Unit of Mineral Resources and Geophysics National Laboratory for Energy and GeologyAmadoraPortugal Faculty of Sciences and Technology Campus da CaparicaNew University of LisbonLisbonPortugal

The chemical and physical properties of rhenium render it a highly demanded metal for advanced applications in important industrial fields. This very scarce element occurs mainly in ores of porphyry copper-molybdenum deposits associated with the mineral molybdenite, MoS2, but it has also been found in granite pegmatites and quartz veins as well as in volcanic gases. Molybdenite is a typical polytype mineral which crystal structure is based on the stacking of [S-Mo-S] with molybdenum in prismatic coordination by sulphide anions;however, it is not yet clearly established if rhenium ions replace Mo4+ cations in a disordered way or else, if such replacement gives rise to dispersed nanodomains of a rhenium-rich phase. As a contribution to clarify this question, an X-ray absorption spectroscopy (XANES) study using synchrotron radiation was performed at the Re L3-edge of rhenium-containing molybdenite samples. Obtained results are described and discussed supporting the generally accepted structural perspective that rhenium is mainly carried by molybdenite through the isomorphous replacement of Mo, rather than by the formation of dispersed Re-specific nanophase(s).

关键词： Molybdenite Polytypes Rhenium Re L_(3)Absorption Edge XANES

Growth and Photosynthetic Pigments of Cotton Cultivars Irrigated with Saline Water

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Agricultural Sciences 2019年第1期10卷 81-91页

作者： Elka Costa Santos Nascimento Ronaldo do Nascimento André Alisson Rodrigues da Silva Carlos Vailan de Castro Bezerra mateus Costa batista Luana Lucas de Sá Almeida Veloso Márcia Cristina de Araújo Pereira Hallyson oliveira Federal University of Campina Grande Campina Grande Brazil

The cultivation of cotton is a relevant socioeconomic activity in the Brazilian agricultural scenario. In the Brazilian Northeast, however, production is limited by low rainfall, requiring water supplementation, a problem for the cotton cultivation practiced in the semi-arid region, due to the presence of saline ions in several water sources, from where the water is used for irrigation. It is necessary to identify cultivars that better tolerate saline stress in order to provide subsidies for their cultivation under such conditions. In this sense, the objective was to evaluate the tolerance of cotton cultivars to salinity. The experiment was conducted in a greenhouse, belonging to the Natural Resource Technology Center of the Federal University of Campina Grande, Campus I, Campina Grande, Brazil, in a completely randomized design in a 2 × 5 factorial scheme, with four replications, totaling 40 experimental units (BRS 368 RF and BRS SAFIRA) submitted to five saline levels (1.5, 3.0, 4.5, 6.0 and 7.5 dS·mˉ1). Irrigation with water saline of EC from 1.5 dS·mˉ1 affects adversely the growth of cotton cultivars, causing reductions in plant height, stem diameter, leaf area and number of leaves. Saline stress reduced the levels of the photosynthetic pigments of the cotton plants studied.

关键词： Gossypium hirsutum L. Salinity Chlorophyll

Evaluation of the Therapeutic Response and Improvement in the Quality of Life of the Patient with Darier Disease to Acitretin through an Analogy between Close Relatives

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Biosciences and Medicines 2017年第8期5卷 48-54页

作者： Thiago Sande Miguel mateus de oliveira Reis Bruno Fonseca dos Santos Aline da Silva Rocha Nayrton Kalys Cruz dos Anjos Lívia Cristina de Melo Pino daniel Almeida da Costa The Medical School at the Center of Higher Education of Valenca Valenca Brazil

Darier disease (DD), also known as follicular keratosis, is a rare autosomal dominant hereditary acantholytic dermatosis caused by a mutation in the ATP2A2 gene. Skin lesions are characterized by persistent confluent papules, preferentially located on the seborrheic areas of the face, chest and back. The hands, feet and nails are also commonly affected. DD has a chronic course with frequent relapses. Their treatment is often difficult and unsatisfactory. We present the case of a 54-year-old male with a history of keratotic papules with a brownish-black color, with a foul-smelling, pruritic and ardent appearance on the back and trunk, since the age of 19, which worsen in the summer. His 27-year-old daughter has a similar picture with her skin lesions started at age of 17 in the region below the breast, back, trunk, feet and hands. After the skin biopsy, the diagnosis was confirmed and acitretin 30 mg/day was instituted. The importance of this case report is to alert health professionals that the diagnosis of DD should be considered in family members of patients, especially those in the first degree, and also in patients with follicular keratolytic dermatoses, being an important differential diagnosis of this group of patients diseases.

关键词： Darier’s Disease Follicular Keratosis Hereditary dermatosis

Importance of Primary Health Care in Medicine: Simultaneous Analysis of Two Colleges, under the Vision of Teachers and Students

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Biosciences and Medicines 2017年第11期5卷 6-12页

作者： Sebastiao Celio Horta Coelho Filho Thiago Sande Miguel Nayrton Kalys Cruz dos Anjos mateus de oliveira Reis Bruna Sande Miguel Vinicius Sande Miguel Aline Gabriela Santos Costa Lilian Costa Brito Bruno Fonseca dos Santos Veronica Clemente Villar Martini daniel Almeida da Costa The Medical School at the Center of Higher Education of Valenca ValencaBrazil Unigranrio Medical School Rio de JaneiroBrazil

Introduction: The involvement of undergraduate student at the beginning of their training in activities based on Primary Health Care (PHC), provides preventive and health promoting actions, and ensures the evaluation of the vulnerability of communities and people. Objectives: To analyze the opinion of students and teachers of two medicine higher education institutions on the relevance of Primary Health Care in this course. METHODS: Students and teachers should be effectively enrolled in order for the study to be conducted, being chosen in a random manner and without interferences on the part of the researchers so that the work was as reliable as possible. A cross-sectional study was conducted with interviews structured in questionnaires about what they thought about PHC. To some students and teachers of the medical course of Valen?a and Grande Rio University (UNIGRANRIO). Before receiving the questionnaire, all interviewed signed a Free and Informed Consent Term, which included the objectives and methodology of the work. Results: 310 students and 51 teachers participated in the study, where 91.43% of the students and 100% of the teachers affirmed that primary care plays a fundamental role in medical education. 94.86% of students and 97.91% of teachers, claimed that the discipline allows a greater contact between undergraduates and community. When questioned about the encouragement that teachers give to students to pursue a career in PHC, 57.87% of the students and 70.83% of the professors said they lacked in such a stimulus. Conclusion: PHC is still very neglected by governmental policies, educational institutions and by the own teachers, that often, turn they attention only to tertiary medicine and, as a consequence, a discouragement of this area occur. Therefore, a higher PHC value is necessary, allowing a more humane look at the patient, valuing their feelings, anguishes and their pathological framework.

关键词： Primary Health Care Graduation Medicine