The Bohemians

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Bayesian methodology for probabilistic description of mechanical parameters of masonry walls

In consideration of the high vulnerability of the built environment, the assessment of seismic behavior of existing masonry buildings is a key topic in view of their retrofitting and reuse. Because masonry's behavior depends on complex nonhomogeneous, anisotropic, asymmetric, and nonlinear properties, the definition of suitable mechanical models is still a critical issue, especially for stone masonry. Structural analyses of existing masonry buildings in seismic-prone areas are thus significantly influenced by the adopted mechanical models and assumptions about their relevant masonry properties, which are characterized by large uncertainty. In this study, a procedure for the definition of masonry classes and probability density functions of relevant mechanical parameters, such as elastic modulus and shear modulus, is proposed. The general procedure is illustrated referring to a significant number of in situ double-flat-jack test results on stone masonry obtained by the authors during an ad hoc experimental campaign. Finally, combining information on masonry quality obtained by visual inspection with results of in situ tests, a Bayesian methodology is proposed for the updating of masonry mechanical parameters, thereby providing the basis for a more refined probabilistic assessment of the seismic risk index. DOI: 10.1061/AJRUA6.0001110. This work is made available under the terms of the Creative Commons Attribution 4.0 International license, https://creativecommons.org/licenses/by/4.0/

Nonfatal accidents among adolescents students in the city of Belém, Pará, Brazil

OBJECTIVE: Study the frequency of nonfatal accidents among adolescent students in the city of Belém, Pará, Brazil. METHODS: This cross-sectional study enrolled a probabilistic sample of 2,828 adolescent students, aged 17 and 18 years old, chosen in clusters obtained in multiple stages. Students were in their final year of high school, in public and private schools of the city of Belém, during the year 2000. Data was collected through a self-administered semi-structured questionnaire. Statistical analysis to compare the categorical variables between the two groups used the chi-square calculated by the Epitable of Epi-Info 6.01. RESULTS: The students' mean age was 17.7 years; 60% were female; 82% studied in public schools; 61% lived with both parents; and 23% with only one of their parents. The occurrence of at least one accident was reported by 1,987 (70%) adolescents. The most frequent types were: falls (35%), contact with sharp glass, knife, sword and dagger (30%), contact with heat and hot substances (22%), transport accidents (20%) and bite by dogs and other mammals (18%). Accidents were more frequent among males (78%) than females (65%), and among students of private schools (77%) than those of public schools (69%). One third of the accidents led the adolescents to healthcare services and, of these, 9% were hospitalized. CONCLUSIONS: A high accident rate was seen among adolescent students, confirming the vulnerability of this age group. Better social conditions, here represented by attendance of private schools, did not confer protection against accidents in this population.OBJETIVO: Verificar a ocorrência de acidentes não fatais em adolescentes escolares do município de Belém, Pará. MÉTODOS: Estudo transversal. Amostra probabilística por conglomerados obtida em múltiplos estágios, que incluiu 2.828 adolescentes escolares, com idades entre 17 e 18 anos, matriculados na terceira série do ensino médio de escolas públicas e privadas de Belém, no ano 2000. Coleta de dados: questionário semi-estruturado de autopreenchimento. Análise estatística: comparação das variáveis categóricas por teste do qui-quadrado, calculado pelo programa Epitable, do Epi-Info 6.01. RESULTADOS: A média de idade dos escolares foi 17,7 anos, sendo 60% meninas, 82% estudavam na rede pública, 61% residiam com pai e mãe e 23% com apenas um dos genitores. A ocorrência de pelo menos um acidente foi relatada por 1.987 (70%) adolescentes. Os mais freqüentes foram: quedas (35%), contato com vidro, faca, espada e punhal (30%), contato com fonte de calor ou substâncias quentes (22%), acidentes de transporte (20%) e mordeduras por cão ou outros mamíferos (18%). A ocorrência foi maior no sexo masculino (78%) do que no feminino (65%) e entre estudantes da rede privada (77%) em comparação aos da rede pública (69%). Um terço dos acidentes levou os adolescentes à procura do serviço de saúde e, destes, 9% foram hospitalizados. CONCLUSÕES: Verificou-se elevada ocorrência de acidentes em adolescentes escolares, confirmando a vulnerabilidade desta faixa etária. Concluiu-se que a melhor condição social, aqui representada pela procedência da escola privada, não conferiu proteção a esses escolares.Universidade do Estado do Pará Disciplina de PediatriaUniversidade Federal de São Paulo (UNIFESP) Departamento de Pediatria Disciplina de Pediatria Geral e ComunitáriaUNIFESP Departamento de Clínica Disciplina de Medicina Baseada em EvidênciasUNIFESP, Depto. de Pediatria Disciplina de Pediatria Geral e ComunitáriaUNIFESP, Depto. de Clínica Disciplina de Medicina Baseada em EvidênciasSciEL

Dissecting the Pharmacodynamics and Pharmacokinetics of MSCs to Overcome Limitations in Their Clinical Translation

Recently, mesenchymal stromal stem cells (MSCs) have been proposed as therapeutic agents because of their promising preclinical features and good safety profile. However, their introduction into clinical practice has been associated with a suboptimal therapeutic profile. In this review, we address the biodistribution of MSCs in preclinical studies with a focus on the current understanding of the pharmacodynamics (PD) and pharmacokinetics (PK) of MSCs as key aspects to overcome unsatisfactory clinical benefits of MSC application. Beginning with evidence of MSC biodistribution and highlighting PK and PD factors, a new PK-PD model is also proposed. According to this theory, MSCs and their released factors are key players in PK, and the efficacy biomarkers are considered relevant for PD in more predictive preclinical investigations. Accounting for the PK-PD relationship in MSC translational research and proposing new models combined with better biodistribution studies could allow realization of the promise of more robust MSC clinical translation. The number of clinical trials based on MSCs that are publicly available exceeds 800; however, data regarding MSC pharmacodynamics (PD), pharmacokinetics (PK), and biodistribution are still scarce. For this reason, we dissected the PD and PK properties of MSCs, presenting factors that may influence MSC-based PK studies to then conceive a new PK-PD model that would support better and more robust MSC clinical translation

Microbiological Valorisation of Bio-composites Based on Polylactic Acid and Wood Fibres

The use of wood fibres for production of bio-based composites has attracted interest in various application sectors ranging from packaging to automotive components and in other high value applications. In the course of the present research activity, several bio-based composites were developed using wood fibres with a compostable polymeric matrix such as polylactic acid (PLA) and a flexible biodegradable polymer such as poly(butylene adipate-co-terephthalate) (PBAT). The developed materials were used for the manufacture of several prototypes for food packaging (trays, boxes for refrigerated or frozen fish, egg box), agricultural applications (pots and yarns), automotive components (spoiler and seats) as well as containers for cosmetics and chemicals. Biodegradability and compostability are desired properties, allowing bio-recycling as end of life scenario, mainly for materials used in food packaging and agricultural applications. Thus, they may be recycled at the end of their life time service producing compost as a value-added by-product. Composting is the main option for bio-recycling but also other valuable pathways can be pursued. Because lignocellulose is one of the components of developed materials, several by-products such as enzymes, reducing sugars, proteins, amino acids, carbohydrates, organic acids, etc. may be obtained from the bio-composites produced. Alternatively, the bio-composites can be also used for the production of yeast biomass. This is important as another recyclability way of the new produced materials. In the present research the bio-composites produced were investigated as substrates for the production of the methylotrophic yeast Pichia pastoris, a potential source of single-cell protein (SCP), β-carotene, and Rhodotorula sp. as potential source of food and feed grade colorant. This is another more valuable alternative to the composting considering also that composting cannot be used to dispose of large quantities of bio-plastics, and in the future it will become more and more important to find alternative routes of valorisation for bio-plastics disposal

Conversion of the hydrochar recovered after levulinic acid production into activated carbon adsorbents

Levulinic acid production by acid-catalyzed hydrothermal conversion of (ligno)cellulosic biomass generates significant amounts of carbonaceous hydrochar, which is currently considered a final waste. In this work, the hydrochar recovered after the levulinic acid production, was subjected to cascade pyrolysis and chemical activation treatments (by H3PO4 or KOH), to synthesize activated carbons. The pyrolysis post-treatment was already effective in improving the surface properties of the raw hydrochar (Specific Surface Area: 388 m2/g, VP: 0.22 cm3/g, VMESO: 0.07 cm3/g, VMICRO: 0.14 cm3/g), by removing volatile compounds. KOH activation resulted as the most appropriate for further improving the surface properties of the pyrolyzed hydrochar, showing the best surface properties (Specific Surface Area: 1421 m2/g, VP: 0.63 cm3/g, VMESO: 0.10 cm3/g, VMICRO: 0.52 cm3/g), which synergistically makes it a promising system towards adsorption of CO2 (∼90 mg/g) and methylene blue (∼248 mg/g). In addition, promising surface properties can be achieved after direct chemical activation of the raw hazelnut shells, preferably by H3PO4 (Specific Surface Area: 1918 m2/g, VP: 1.34 cm3/g, VMESO: 0.82 cm3/g, VMICRO: 0.50 cm3/g), but this choice is not the smartest, as it does not allow the valorization of the cellulose fraction to levulinic acid. Our approach paves the way for possible uses of these hydrochars originating from the levulinic acid chain for new environmental applications, thus smartly closing the biorefinery loop of the hazelnut shells

Minor-but-Complex Liver Resection: An Alternative to Major Resections for Colorectal Liver Metastases Involving the Hepato-Caval Confluence

Major hepatectomy (MH) is often considered the only possible approach for colorectal liver metastasis (CRLM) at the hepato-caval confluence (CC), but it is associated with high morbidity and mortality. With the aim to reduce MH, we developed the "minor-but-complex" (MbC) technique, which consists in the resection of less than 3 adjacent liver segments with exposure of the CC and preservation of hepatic outflow until spontaneous maturation of peripheral intrahepatic shunts between main hepatic veins. We have evaluated applicability and outcome of MbC resections for the treatment of CRLM involving the CC. In this retrospective cohort study, all consecutive liver resections (LR) performed for CRLM located in segments 1, 7, 8, or 4a were classified as MINOR - removal of bC - removal of = 3 adjacent segments. The rate of avoided MH was obtained by the difference between the rate of potentially MH (PMH) plus potentially inoperable cases and the rate of the MH performed. Taking into account that postoperative mortality is mainly related to the amount of resected liver, MbC was compared with minor resections for safety, complexity, and outcome. Of the 59 LR analyzed, 29 (49.1%) were deemed PMH and 4 (6.8%) potentially inoperable. Eventually, MH was performed only in 8 (13.5%) with a decrease rate of 42.4%. Minor LR was performed in 23 (39.0%) and MbC LR in 28 (47.5%) patients. Among MbC cases, 32.1% had previous liver treatments, 39.3% required vascular reconstruction (no reconstructed vessel thrombosis occurred before maturation of peripheral intrahepatic shunts between main hepatic veins), and 7.1% had grade IIIb-IV complications, their median hospital stay was 9 days and 90-day mortality was 0%. After a median follow-up of 22.2 months, oncological results were comparable with those of minor resections. MbC hepatectomy lowers the need for MH and allows for the resection of potentially inoperable patients without negative impact on safety and survival