RESUMO
Nanocomposites with different ratios of titanium dioxide and bismuth vanadate [TiO2]/[BiVO4] give rise to compatible electronic band structure alignment at their interfaces to ensure enhanced photoactivated charge transfer under visible light. The sol-gel method and suitable post-synthesis thermal treatments were used to synthesize different compositions with stabilized anatase phase of TiO2 and monoclinic scheelite polymorph BiVO4. Structural, electronic and optical characterizations were performed and the results were analysed as a function of the stoichiometry, in which both crystalline structures show a clear junction formation among their characteristic stacking planes. Photocatalytic and (photo) electrochemical responses of the nanocomposites were investigated and tested for the degradation of azo dyes (Acid Blue-113, AB-113) (~ 99%) under visible light radiation. The nanocomposite with a mass ratio of (1:10) shows the highest photocatalytic efficiency compared to the other compositions. HRTEM images showed marked regions in which both crystalline structures form a clear junction and their characteristic planes. However, the increase of BiVO4 content in the network overcomes the photocatalytic activity due to the decrease in the reduction potential of the photo-generated electrons with high recombination rates.
RESUMO
In this work two high density functional theory (DFT) correlation methodologies, the so called DFT+U (or GGA+U) implementation and the exact exchange of correlated electrons (EECE), hybrid DFT functional (or one case of hybrid DFT), are tested to determine the mechanical properties of americium-II. For each case, the numeric value of their principal parameter is chosen ([Formula: see text] for the first case and [Formula: see text] for the second one) once the crystalline structure meets all the mechanical stability conditions. The results show that there is a range of values of [Formula: see text] and [Formula: see text] in which both methodologies generate a stable (experimentally correct) non-magnetic ground state, reaching approximately the same numeric value of the set of elastic constants of the cubic structure. However, only for the case of the hybrid functional results it is possible to show how the non-magnetic configuration is energetically favored, as compared to the ferromagnetic configuration. This happens around [Formula: see text], a value in agreement with a previous analysis made under the same methodology for the metal case Am-I. Following a detailed and deep analysis, it is possible to find a close interrelation between the electronic properties of the metal: its distribution of states around the Fermi level, the energy difference between the two possible spin configurations, and the mechanical response of the crystal. Also, it is possible to conclude that the effect of alpha parameter on the [Formula: see text] electrons can be used as a parameter to simulate the presence of an external pressure over the structure. For the comparison, the calculations were performed within the LAPW approximation in DFT as implemented in the WIEN2k code, with a finite deformation method.
RESUMO
AIM: To quantify Substance P (SP) and Calcitonin gene-related peptide (CGRP) expression in healthy human periodontal ligament from premolars after root canal preparation with Reciproc Blue, WaveOne Gold, XP EndoShaper and hand files. METHODOLOGY: A total of 50 human periodontal ligament samples were obtained from healthy mandibular premolars where extraction was indicated for orthodontic reasons. Prior to extraction, 40 of these premolars were equally divided into four groups, and root canals were prepared using four different systems: Reciproc Blue, WaveOne Gold, XP EndoShaper and a hand instrumentation technique. The remaining 10 healthy premolars were extracted without treatment and served as a negative control group. All periodontal ligament samples were processed, and SP and CGRP were measured by radioimmunoassay. The Kruskal-Wallis test was used to establish significant differences between groups and LSD post hoc comparisons were also performed. RESULTS: Greater SP and CGRP values were found in the hand instrumentation group, followed by the XP EndoShaper, WaveOne Gold and the Reciproc groups. The lower SP and CGRP values were for the healthy periodontal ligament group. The Kruskal-Wallis test revealed significant differences between groups (P < 0.05). Post hoc Least Significant Difference (LSD) tests revealed significant differences (P < 0.05) in SP and CGRP expression between all the comparisons except for the Reciproc Blue and WaveOne Gold group (P > 0.05). CONCLUSION: All the root canal preparation techniques tested increased SP and CGRP expression in human periodontal ligament, with hand files and XP EndoShaper instruments being associated with greater neuropeptide release compared to Reciproc Blue and WaveOne Gold files.
Assuntos
Peptídeo Relacionado com Gene de Calcitonina/biossíntese , Ligamento Periodontal/metabolismo , Preparo de Canal Radicular/instrumentação , Substância P/biossíntese , Adolescente , Adulto , Dente Pré-Molar , Colômbia , Instrumentos Odontológicos , Desenho de Equipamento , Humanos , Mandíbula , Teste de Materiais , Periodontite Periapical/terapia , Preparo de Canal Radicular/métodos , Adulto JovemRESUMO
AIM: The aim of this paper was to test the hypothesis that an expandable prosthesis with dual cage-and-plate function can provide immediate and durable spine stabilization after corpectomy. METHODS: We designed an expandable vertebral body prosthesis with dual cage-and-plate function in a single device (JR-prosthesis). Anatomical studies were performed to design a titanium-made prosthesis. Cadaver assays were done with a stainless steal device to test fixation and adequacy to the human spine anatomy. Then, 14 patients with vertebral tumors (8 metastatic) underwent corpectomy and vertebral body replacement with the JR-prosthesis. RESULTS: All patients had neurological deficit, severe pain and spine instability (mean follow-up: 25.4 months). Mean pain score before surgery in a visual analog scale improved from 7.6 to 3.0 points after operation (P=0.002). All patients achieved at least one grade of improvement in the Frankel score (P=0.003), excepting the 3 patients with Frankel grade A presurgery. Two patients with renal cell carcinoma died during the following 4 days after surgery (renal failure and massive bleeding), the rest attained a painless and stable spine immediately and maintained for long periods. No significant infections or implant failures were registered. A non-fatal case of inferior vena cava surgical injury was observed (repaired during surgery without further complications). CONCLUSION: The JR-prosthesis stabilizes the spine immediately after surgery and for the rest of the patients' life. To our knowledge, this is the first report on the clinical experience of any expandable vertebral body prosthesis with dual cage-and-plate function in a single device. These observations await confirmation in different scenarios.
Assuntos
Plasmocitoma/cirurgia , Desenho de Prótese , Implantação de Prótese/métodos , Fusão Vertebral/instrumentação , Fusão Vertebral/métodos , Neoplasias da Coluna Vertebral/cirurgia , Adenocarcinoma/cirurgia , Adulto , Idoso , Placas Ósseas , Neoplasias da Mama/patologia , Carcinoma de Células Renais/cirurgia , Criança , Discotomia , Feminino , Seguimentos , Humanos , Neoplasias Renais/patologia , Masculino , Pessoa de Meia-Idade , Osteossarcoma/cirurgia , Titânio , Resultado do Tratamento , Adulto JovemRESUMO
The vertical and diurnal variation of nitrogen and phosphorus forms, as well as that of soluble reactive silica (SRS), were studied in four sampling days at Gar9as reservoir, a shallow tropical one located in the city of São Paulo, in southeastern Brazil. Except for N-NH4, all other inorganic forms of nitrogen (N-NO2, N-NO3, and total N) demonstrated decreased concentrations toward the bottom of reservoir. Similarly, all showed significant diurnal differences on every sampling day, with increased values during the night due to absence of photosynthetic assimilation during that period. In the sampling days, these forms decreased on the spring sampling day due to the bloom of Microcystis registered during this period of the year. All three forms of phosphorus (SRP, particulate P, and total P) showed significant vertical variation, except on the fall sampling day. On the summer sampling day there was an increase of both total P and particulate P, the latter because it constitutes more than 70% of the total P during all sampling days. Hourly phosphorus variation was significant during all sampling days, except for the summer one. The SRS vertical variation was significant during all sampling days, except for that in the spring. It was also different hourly on sampling days.
Assuntos
Ecossistema , Água Doce/química , Nitrogênio/análise , Fósforo/análise , Fitoplâncton/fisiologia , Silício/análise , Animais , Brasil , Monitoramento Ambiental/métodos , Estações do AnoRESUMO
Variações vertical, nictemeral e entre os dias de amostragem das formas de nitrogênio, fósforo e sílica solúvel reativa (SRS) foram estudadas no lago das Garças, reservatório tropical raso situado na cidade de São Paulo, sudeste do Brasil. Excetuado o N-NH4, todas as demais formas inorgânicas de nitrogênio (N-NO2, N-NO3 e N total) diminuíram de teor no sentido do fundo do reservatório. Da mesma maneira, todas as formas de nitrogênio apresentaram diferenças significativas quanto às horas de amostragem, aumentando seus valores durante a noite, em razão da ausência de fotossíntese nesse período. Essas formas diminuíram seus teores no dia de amostragem da primavera, graças à floração de Microcystis registrada nesse período. Os valores das três formas de fósforo estudadas (solúvel reativo, particulado e total) apresentaram variação vertical significativa, exceto no dia da amostragem de outono. No dia de amostragem de verão ocorreu aumento dos valores de P total e particulado, sendo que este último constituiu mais de 70% do P total durante todos os dias de amostragem. Considerando as horas, a variação dos teores de fósforo foi significativa nos dias das amostragem de primavera, de outono e de inverno. A variação vertical da sílica reativa solúvel foi significativa em todos os dias de amostragem, menos no da primavera. Essa variação também foi diferente entre as horas e os dias de amostragem.
Assuntos
Animais , Ecossistema , Água Doce/química , Nitrogênio/análise , Fósforo/análise , Fitoplâncton/fisiologia , Silício/análise , Brasil , Monitoramento Ambiental/métodos , Estações do AnoRESUMO
In the 5th Region, located in central Chile, infrastructure projects are being implemented in order to increase the capacity to treat and dispose of sewage. In order to analyse the sludge management alternatives the ORWARE model was used. The research project was divided in two stages: in the first stage, the sewage and sludge management strategies to be compared as well as the objectives were established. The management alternatives chosen were for chemical or biological treatment of sewage while for sludge the management alternatives were based on digestion, composting or lime stabilisation. The second stage included simulation and analysis of results. The main conclusions of the work were: if "lowest possible emissions" is the main objective of sewage treatment, biological treatment should be applied. Regarding pathogen reduction, both chemical precipitation and biological treatment attain an adequate reduction if the treated sewage is to be discharged to the sea. On the other hand, additional disinfection is needed in the case of discharge to rivers. Control at source should be stressed to avoid heavy metals and toxic organic compounds in the sludge.
Assuntos
Modelos Teóricos , Esgotos , Eliminação de Resíduos Líquidos/métodos , Chile , Cidades , Conservação dos Recursos Naturais , Desinfetantes , Metais Pesados , Nitrogênio/isolamento & purificação , Fósforo/isolamento & purificação , Purificação da Água/métodosRESUMO
Spatial and temporal variation of climatic and physical characteristics in a shallow tropical reservoir in the city of São Paulo, Southeastern Brazil, and their possible influence on the dynamics of the phytoplankton population. Samples were taken at 5 depths of the water column (subsurface: 1% Io, 10% Io, 2 m, and bottom) and at 4 hour intervals (6:00, 10:00, 14:00, 18:00, 22:00, 2:00, and 6:00 h) during summer (March 3-4), fall (June 13-14), winter (August 29-30), and spring (November 29-30) of 1994 at a single sampling station. Garças Reservoir (23 degrees 39'S, 46 degrees 37'W) is a kinetic turbulent system, highly influenced by winds, with stratification that may last for days or weeks, and which undergoes mixing periods more than once in a year. A thermal pattern of this type is comparable to the warm discontinuous polymetric. Considering its optical properties, the water body was classified as an ecosystem with moderate turbidity, which decreases basically due to increased phacopigment concentration during the spring. Also, the reservoir is an ecosystem whose phytoplanktonic community is subjected to stress, the degree of which depends on level of light penetration.
Assuntos
Ecossistema , Fitoplâncton/fisiologia , Abastecimento de Água , Brasil , Estações do Ano , Temperatura , Microbiologia da ÁguaRESUMO
Spatial and temporal variation of climatic and physical characteristics in a shallow tropical reservoir in the city of Säo Paulo, Southeastern Brazil, and their possible influence on the dynamics of the phytoplankton population. Samples were taken at 5 depths of the water column (subsurface: 1 percent Io, 10 percent Io, 2 m, and bottom) and at 4 hour intervals (6:00, 10:00, 14:00, 18:00, 22:00, 2:00, and 6:00 h) during summer (March 3-4), fall (June 13-14), winter (August 29-30), and spring (November 29-30) of 1994 at a single sampling station. Garças Reservoir (23º39'S, 46º37'W) is a kinetic turbulent system, highly influenced by winds, with stratification that may last for days or weeks, and which undergoes mixing periods more than once in a year. A thermal pattern of this type is comparable to the warm discontinuous polymictic. Considering its optical properties, the water body was classified as an ecosystem with moderate turbidity, which decreases basically due to increased phaeopigment concentration during the spring. Also, the reservoir is an ecosystem whose phytoplanktonic community is subjected to stress, the degree of which depends on level of light penetration
Assuntos
Ecossistema , Fitoplâncton , Abastecimento de Água , Brasil , Estações do Ano , Temperatura , Microbiologia da ÁguaRESUMO
UNLABELLED: The annual rises in the cost of claims suffered by some countries had led to increases in: costs of the attention; malpractice premiums; health personnel stress level; risks for the patients with difficult problems, and lack of opportune attention. The intricate interaction between clinical state, responses variability and medical procedures flaws makes impossible stop unavoidable outcomes (UO). Though UO are not derived from negligence or inability, patients and relatives can see it as a malpractice result. OBJECTIVE: To determine the proportion of complaints generated by UO related perceptions (UORP) and their distribution in obstetric and gynecologic stages of care. MATERIAL AND METHODS: A search for claims derived from gynecologic or obstetric care was undertaken in the Medical Arbitrition National Commission (CONAMED) database, those presented between Jun. 1, 1996, and Nov. 30, 1998, were chosen. Some claims were derived directly from UORP (D-UORP claims), others were derived indirectly (UORP clamis); claims were grouped for stage of the attention in which they were originated; non D-UORP claims were grouped also by motives. RESULTS: In 625 claims (98.6% of total) was possible obtain precise information as required for the study. 79% of complaints were derived from UORP; 17% from perceptions generated for medical activities unrelated to UO (MAU-UO claims) and 4% by perception originated from care system (CS claims). 46% of complaints concerned surgical treatment, 27% medical treatment, 14% initial study, 2.1% delivery, in 10% a specific stage of the attention was not mentioned. The motives of the non D-UORP complaints were: 1) I-UORP claims; a) opportunity of the action, when the patient referred delay or inopportuneness as cause of the complaint (17%, overall); b) Professional quality, when questioned de outcomes or medical criteria (23%); 2) MAU-UO claims: a) Professional capacity when patient questions ability, or complaint of error in diagnosis (failure to diagnose or incorrect diagnosis), wrong removal, unnecessary treatment or other actions outside of the norm (13%); b) Improper information (3%); c) Inappropriate manner (0.8%); 3) CS claims: a) Resources (1%); b) Accessibility (2.9%). COMMENTS: The damage risk attributable to medical negligence is very low among patients who had received obstetrical or gynecological care, most of the complaints are UORP generated. In obstetrical care--from 1997 national statistics and described results--a benefit was procured to 1,705,161 persons and were produced 17 possible wrong attentions by professional capacity, five by improper information and one by inappropriate manner; the rest, 123 complaints, were derived from perceptions induced by UO. Undoubtedly there is low complaint registration, however, even at worst the wrong attention effect is lower than the impact attained if the possibility of economic benefit search through medical demands is not totally canceled. The damage risk derived from cost of claims is greater, as suffered on many countries. Medical associations in countries without professional liability problems must accomplish negotiations so that the legislation does not establish compensations by medical care results, the request may be based in: a) the deleterious consequences derived from cost of claims; and, b) the low probability of affecting the patients interests, in Mexico complaints derived from perceptions about the professional capacity are one in 103,022 obstetrical care attentions, the improper information derived one in 316,989 and the inappropriate manner generated one in 1,373,620. These organizations and other health related could assume the commitment to abate the foreseeable complaints and to do research on feasible forms to forecast UO, technically this must be long-range and though international collaboration.
Assuntos
Ginecologia , Imperícia/estatística & dados numéricos , Obstetrícia , Percepção , Resultado do Tratamento , Bases de Dados Factuais , Feminino , Humanos , México , GravidezRESUMO
UNLABELLED: The study of claims motives is relevant since Obstetrics and Gynecology (O&G) is one of the specialties that it is involved with greater frequency in demands in the Medical Arbitration National Commission (CONAMED). OBJECTIVE: In order to know the causes by those which the patients have attended to be complained of the attention provided by a Obstetrician/Gynecologist (OG). MATERIAL AND METHODS: Between June 1, 1996, and November 30, 1998, there were 635 demands reported to the CONAMED for obstetrical or gynecological care, 375 (60%) derived from obstetrical care; claims were grouped by motives and for stage of the attention in which they were originated. RESULTS: There were more than 17 different causes of claim, the most frequent were: complications (20%), care not opportune (16%), accidents (15%), improper actions (15%), diagnostic error (10%). Claims were derived from: Surgical procedures (45%), medical treatment (27%) and diagnosis (13%). 15 (2.4%) of claims were generated from vaginal delivery, but only 9 (1.4%) were obstetrician related. Obstetric surgical procedures account for 23% of claims. CONCLUSIONS: OG are more claimed because work harder, more than one million vaginal and more than 500,000 cesarean deliveries are performed yearly in Mexico. The rates of reported claims are low, one per 10,000 deliveries attended; one per 275,000 vaginal deliveries, one per 8,400 obstetric surgical procedures. It all points OG claims as a probabilistic problem, risk related.