91 research outputs found
The West Zone of Rio de Janeiro as an Axis of Urban Expansion for Social Interest Housing: Considerations from the ‘Minha Casa Minha Vida’ Program in Senador Camará
Este artigo analisa a participação da política habitacional pública da Prefeitura do Rio de Janeiro no incremento do padrão histórico de produção social do espaço urbano, caracterizado por sua forma periférica e rarefeita de urbanidade. Para isso, discute o caso do Programa Minha Casa Minha Vida (PMCMV) no bairro Senador Camará, na Zona Oeste do Rio. O texto mostra como o PMCMV reitera características de um processo de urbanização marcado historicamente pela segregação socioespacial e reafirma disparidades socioespaciais, em vez de ser um importante vetor de qualificação de áreas precárias e de promoção de um modelo mais igualitário de ocupação do território.This paper analyzes the participation of the Rio de Janeiro’s City Hall in the increment of the historical pattern of social production of the urban space, characterized by its peripheral and rarefied form of urbanity. To this end, it discusses the case of the Minha Casa Minha VidaProgram (PMCMV) in the Senador Camará neighborhood, in Rio’s West Zone. The paper shows how the PMCMV reiterates characteristics of an urbanization process historically marked by socio-spatial segregation and reaffirms socio-spatial disparities, instead of being an important vector for the qualification of precarious areas and the promotion of a more egalitarian model of territorial occupation.
Dual Doping of MoP with M(Mn,Fe) and S to Achieve High Hydrogen Evolution Reaction Activity in Both Acidic and Alkaline Media
Rational design of cost‐effective, high performance and stable hydrogen evolution reaction (HER) electrocatalysts in both acidic and alkaline media holds the key to the future hydrogen‐based economy. Herein, we introduce an effective approach of simultaneous non‐metal (S) and metal (Fe or Mn) doping of MoP to achieve excellent HER performance at different pH. The catalysts show remarkable overpotentials at −10 mA cm−2 of only 65 and 68 mV in 0.5 M H2SO4, and 50 and 51 mV in 1.0 M KOH, respectively, as well as much higher turnover frequencies compared to undoped MoP. Furthermore, the catalysts exhibit outstanding long‐term stability at a fixed current of −10 mA cm−2 for 40 h. The effects of both dopants, such as electronic structure modification and enhancement of the intrinsic activity, increase of the electrochemically active surface area, and formation of coordinatively unsaturated edge sites, act cooperatively to accelerate the HER at both pH media. Additionally, the presence of oxophilic Mn and Fe at the surface results in Mn or Fe oxide/hydroxide species that promote the dissociation of water molecules in alkaline electrolyte. This work introduces a facile and effective design principle that could pave the way towards engineering highly active HER catalysts for a wide pH range.Metal (Mn or Fe) and non‐metal (S) dual doped MoP catalysts were synthesiszed by reductive pyrolysis of the corresponding Mn,Mo‐ and Fe,Mo‐phosphonates precursors, in the presence of elemental S. The derived catalysts showed remarkable hydrogen evolution reaction (HER) activity in acidic and alkaline media. The dual doping process endowed MoP with proper hydrogen binding energy thus enhancing the HER in acidic media. In addition, Mn and Fe acted as surface oxides species in alkaline medium, which facilitated the water dissociation step.
imageYousef Jameel Scholarship FundPeer Reviewe
Comparing the Performance of Nb2O5 Composites with Reduced Graphene Oxide and Amorphous Carbon in Li‐ and Na‐Ion Electrochemical Storage Devices
Two‐dimensional (2D) reduced graphene oxide (rGO) is often combined with metal oxides for energy‐storage applications, owing to its unique properties. Here, we compare the electrochemical performance of Nb2O5‐rGO and amorphous carbon‐coated‐Nb2O5 composites, synthesized in similar conditions. The composite made of Nb2O5 and amorphous carbon (using 1,3,5‐triphenylbenzene as carbon source) outperforms the Nb2O5‐rGO counterpart as a high rate anode electrode material in Li‐ion and Na‐ion half‐cells and hybrid supercapacitors, delivering specific capacities of 134 mAh g−1 at 25 C against 98 mAh g−1 for the rGO‐based composite (in Li electrolyte) and 125 mAh g−1 at 20 C against 98 mAh g−1 (in Na electrolyte). The organic molecules, which are the precursor of the amorphous carbon, control the size and coat the metal oxide particles more efficiently, leading to more extensive carbon‐oxide contacts, which benefits the energy‐storage performance.Peer Reviewe
Exploiting the Condensation Reactions of Acetophenone to Engineer Carbon-Encapsulated Nb2O5 Nanocrystals for High-Performance Li and Na Energy Storage Systems
Efficient synthetic methods to produce high‐performance electrode‐active materials are crucial for developing energy storage devices for large‐scale applications, such as hybrid supercapacitors (HSCs). Here, an effective approach to obtain controllable carbon‐encapsulated T‐Nb2O5 nanocrystals (NCs) is presented, based on the solvothermal treatment of NbCl5 in acetophenone. Two separate condensation reactions of acetophenone generate an intimate and homogeneous mixture of Nb2O5 particles and 1,3,5‐triphenylbenzene (TPB), which acts as a unique carbon precursor. The electrochemical performance of the resulting composites as anode electrode materials can be tuned by varying the Nb2O5/TPB ratio. Remarkable performances are achieved for Li‐ion and Na‐ion energy storage systems at high charge–discharge rates (specific capacities of ≈90 mAh g−1 at 100 C rate for lithium and ≈125 mAh g−1 at 20 C for sodium). High energy and power densities are also achieved with Li‐ and Na‐ion HSC devices constructed by using the Nb2O5/C composites as anode and activated carbon (YPF‐50) as cathode, demonstrating the excellent electrochemical properties of the materials synthesized with this approach.Peer Reviewe
Niobium pentoxide nanomaterials with distorted structures as efficient acid catalysts
Niobium pentoxides are promising acid catalysts for the conversion of biomass into fuels and chemicals. Developing new synthesis routes is essential for designing niobium pentoxide catalysts with improved activity for specific practical processes. Here we show a synthesis approach in acetophenone, which produces nanostructured niobium pentoxides with varying structure and acidity that act as efficient acid catalysts. The oxides have orthorhombic structures with different extents of distortions and coordinatively unsaturated metal atoms. A strong dependence is observed between the type and strength of the acid sites and specific structural motifs. Ultrasmall niobium pentoxide nanoparticles, which have strong Brønsted acidity, as well as Lewis acidity, give product yields of 96% (3 h, 140 °C, 100% conversion), 85% (3 h, 140 °C, 86% conversion), and 100% (3 h, 110 °C, 100% conversion) in the reactions of furfuryl alcohol, 5-(hydroxymethyl)furfural, and α-angelica lactone with ethanol, respectively.Peer Reviewe
Mesostructured γ-Al2O3-Based Bifunctional Catalysts for Direct Synthesis of Dimethyl Ether from CO2
In this work, we propose two bifunctional nanocomposite catalysts based on acidic mesostructured γ-Al2O3 and a Cu/ZnO/ZrO2 redox phase. γ-Al2O3 was synthesized by an Evaporation-Induced Self-Assembly (EISA) method using two different templating agents (block copolymers Pluronic P123 and F127) and subsequently functionalized with the redox phase using an impregnation method modified with a self-combustion reaction. These nanocomposite catalysts and their corresponding mesostructured supports were characterized in terms of structural, textural, and morphological features as well as their acidic properties. The bifunctional catalysts were tested for the CO2-to-DME process, and their performances were compared with a physical mixture consisting of the most promising support as a dehydration catalyst together with the most common Cu-based commercial redox catalyst (CZA). The results highlight that the most appropriate Pluronic for the synthesis of γ-Al2O3 is P123; the use of this templating agent allows us to obtain a mesostructure with a smaller pore size and a higher number of acid sites. Furthermore, the corresponding composite catalyst shows a better dispersion of the redox phase and, consequently, a higher CO2 conversion. However, the incorporation of the redox phase into the porous structure of the acidic support (chemical mixing), favoring an intimate contact between the two phases, has detrimental effects on the dehydration performances due to the coverage of the acid sites with the redox nanophase. On the other hand, the strategy involving the physical mixing of the two phases, distinctly preserving the two catalytic functions, assures better performances.MIUR—National Program PON Ricerca e InnovazioneUniversity of CagliariFondazione di Sardegna (FdS)Regional Government of Sardinia ASSET projectPeer Reviewe
Fracture-dislocation of the thoracic spine during second trimester of pregnancy: case report and literature review
Spinal fractures associated with spinal cord injury rarely affect pregnant patients. The authors present the case of a 20-year-old woman in her 20th week of pregnancy, who suffered fracture-dislocation of the thoracic spine (T4-T5) and underwent decompression, reduction and posterior fusion with pedicle screws. Despite the complete spinal cord injury presented, the pregnancy progressed uneventfully and resulted in birth via normal delivery of a healthy newborn at term. Some particular features of this case, like the care needed in using ionizing radiation, the surgical approach and delivery, use of steroids and pregnancy complications in such patients are discussed here. Only a multidisciplinary team composed by physicians from different specialties (spinal surgeons, obstetricians and physiatrists), nurses and physiotherapists is capable of assisting pregnant patients with spinal cord injuries satisfactorily.Fraturas da coluna vertebral associadas à lesão medular raramente acometem pacientes gestantes. Os autores apresentam o caso de uma mulher de 20 anos de idade, com gestação de 20 semanas, que sofreu fratura-luxação da coluna torácica (T4-T5) e foi submetida a descompressão, redução e artrodese posterior com parafusos pediculares. Apesar de apresentar lesão medular completa, a gestação evoluiu sem intercorrências e resultou no nascimento, por parto normal, de uma criança saudável a termo. Algumas particularidades, como o cuidado com o uso de radiação ionizante, via de acesso cirúrgico e de parto, corticoterapia e complicações gestacionais em pacientes nessas condições são discutidas neste artigo. Somente uma equipe multidisciplinar, formada por médicos de diferentes especialidades (cirurgiões de coluna, obstetras e fisiatras), enfermeiras e fisioterapeutas é capaz de assistir a essas pacientes de modo satisfatório.Universidade Federal de São Paulo (UNIFESP)Universidade Metropolitana de SantosUNIFESPSciEL
The stress responsive and morphologically regulated hsp90 gene from Paracoccidioides brasiliensis is essential to cell viability
<p>Abstract</p> <p>Background</p> <p><it>Paracoccidioides brasiliensis </it>is a dimorphic fungus that causes the most prevalent systemic mycosis in Latin America. The response to heat shock is involved in pathogenesis, as this pathogen switches from mycelium to yeast forms in a temperature dependent fashion that is essential to establish infection. HSP90 is a molecular chaperone that helps in the folding and stabilization of selected polypeptides. HSP90 family members have been shown to present important roles in fungi, especially in the pathogenic species, as an immunodominant antigen and also as a potential antifungal therapeutic target.</p> <p>Results</p> <p>In this work, we decided to further study the <it>Pbhsp90 </it>gene, its expression and role in cell viability because it plays important roles in fungal physiology and pathogenesis. Thus, we have sequenced a <it>Pbhsp90 </it>cDNA and shown that this gene is present on the genome as a single copy. We have also confirmed its preferential expression in the yeast phase and its overexpression during dimorphic transition and oxidative stress. Treatment of the yeast with the specific HSP90 inhibitors geldanamycin and radicicol inhibited growth at 2 and 10 μM, respectively.</p> <p>Conclusion</p> <p>The data confirm that the <it>Pbhsp90 </it>gene encodes a morphologically regulated and stress-responsive protein whose function is essential to cell viability of this pathogen. This work also enforces the potential of HSP90 as a target for antifungal therapies, since the use of HSP90 inhibitors is lethal to the <it>P. brasiliensis </it>yeast cells in a dose-responsive manner.</p
Oral Health-Related Quality of life and its association with malocclusion and self-perception of dental aesthetics in Adolescents / Qualidade de vida relacionada à saúde bucal e sua associação com má oclusão e autopercepção da estética dentária em adolescentes
Introduction: Studies have shown that malocclusions can have a negative impact on the quality of life and self-esteem of adolescents. This study aimed to verify the association between Oral Health-Related Quality of Life, malocclusion and self-perceived dental aesthetics in Brazilian adolescents. Methods: A cross-sectional study was conducted with a sample of 580 students between 12 and 15 years old. The oral health-related quality of life (OHRQoL) was evaluated using Child OIDP, malocclusion was determined by DAI, self-perceived dental aesthetics was evaluated using the OASIS, and IOTN-AC assessed the self-perceived orthodontic treatment need. The statistical analysis involved descriptive and inferential methods, such as Pearson’s chi-square test or Fisher’s exact test and multiple logistic regressions, with significance level of 5%. Results: The prevalence of oral impact was high (73.4%), 49.1% presented malocclusion and 25.0% had a highly desirable orthodontic treatment need. Negative self-perception of dental aesthetics was observed in 50.0% of adolescents and 13.1% thought they needed orthodontic treatment. The impact on quality of life was associated to gender, self-perceived dental aesthetic (p<0.001), malocclusion + self-perceived dental aesthetic (p<0.001) and self-perceived orthodontic treatment need (p=0.045). The logistic regression results indicated that being female and having negative self-perception of dental aesthetics are directly involved in the quality of life of adolescents. Conclusion: Being female and having a negative self-perception of one’s dental aesthetics are risk factors for impacting negatively on oral health related quality of life
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