Solventless synthesis of ZIF-L and ZIF-8 with hydraulic press and high temperature

In recent years, alternative methods to conventional synthesis of MOFs (metal-organic frameworks) have emerged due to the problematic use of solvents for both the environment and human health. Here we present the synthesis of ZIFs (zeolitic imidazolate frameworks) at high pressure by means of a hydraulic press provided with a heating mechanism. By the optimization of parameters such as temperature, time and the addition of promotor NH4NO3, a considerable increase in the reaction yield was achieved in products, neither washed nor activated, obtained since the first minute of reaction. Depending on the operation conditions, ZIF-L appeared as competing phase with ZIF-8. Upon transformation of ZIF-L into ZIF-8 in presence of ethanol, a reaction yield of 58.2% was achieved to highly crystalline ZIF-8 with a BET specific surface area of 947 m2/g. This green, fast, versatile and improved method suggests a possible way to future synthesis of other MOFs and the possibility of their industrial implementation

Effect of cryopreserved amniotic membrane on the mechanical properties of skeletal muscle after strabismus surgery in rabbits

Purpose: To study the functional recovery of the superior rectus muscle (SRM) after its partial resection in a rabbit model with and without cryopreserved amniotic membrane (AM). Material and methods: Resection of the right and left SRMs of 30 rabbits was performed. On the left eyes, a single sheet of equine cryopreserved AM was placed covering the muscle edge sutured. Active and passive mechanical properties of muscles operated with and without AM were monitored over time at 30 (n = 10), 60 (n = 10), and 90 (n = 10) days after surgery. Muscle samples were extracted and electrically stimulated to register the force exerted by the samples, characterizing its active behavior. They were, then, subjected to stretching test to obtain its resistance to deformation, known as passive behavior. Moreover, right and left eyes of a control group (n = 5) were equally subjected to active and passive tests to characterize the physiological behavior of SRM muscles. Results: On active function examination, statistically significant differences were documented between the following: control vs AM and no AM at 30 days (p = 0.002 and p = 0.04, respectively). All other comparisons were insignificant (p > 0.05). On passive function analysis, significant differences were only found between control vs. no AM at 30 days (p = 0.004) and between AM vs. no AM at 30 days (p = 0.002). Indeed, muscle operated without AM did not recover a normal passive function until 60 days after surgery. Conclusion: Cryopreserved AM is effective in accelerating recovery of SRM passive function in rabbits. Nevertheless, AM produced no significant effect on recovery of SRM active function.

Continuous synthesis of drug-loaded nanoparticles using microchannel emulsification and numerical modeling: Effect of passive mixing

By using interdigital microfluidic reactors, monodisperse poly(d, l lactic-co-glycolic acid) nanoparticles (NPs) can be produced in a continuous manner and at a large scale (~10 g/h). An optimized synthesis protocol was obtained by selecting the appropriated passive mixer and fluid flow conditions to produce monodisperse NPs. A reduced NP polydispersity was obtained when using the microfluidic platform compared with the one obtained with NPs produced in a conventional discontinuous batch reactor. Cyclosporin, an immunosuppressant drug, was used as a model to validate the efficiency of the microfluidic platform to produce drug-loaded monodisperse poly(d, l lactic-co-glycolic acid) NPs. The influence of the mixer geometries and temperatures were analyzed, and the experimental results were corroborated by using computational fluid dynamic three-dimensional simulations. Flow patterns, mixing times, and mixing efficiencies were calculated, and the model supported with experimental results. The progress of mixing in the interdigital mixer was quantified by using the volume fractions of the organic and aqueous phases used during the emulsification–evaporation process. The developed model and methods were applied to determine the required time for achieving a complete mixing in each microreactor at different fluid flow conditions, temperatures, and mixing rates

Active behavior of abdominal wall muscles: Experimental results and numerical model formulation

In the present study a computational finite element technique is proposed to simulate the mechanical response of muscles in the abdominal wall. This technique considers the active behavior of the tissue taking into account both collagen and muscle fiber directions. In an attempt to obtain the computational response as close as possible to real muscles, the parameters needed to adjust the mathematical formulation were determined from in vitro experimental tests. Experiments were conducted on male New Zealand White rabbits (2047. ±. 34. g) and the active properties of three different muscles: Rectus Abdominis, External Oblique and multi-layered samples formed by three muscles (External Oblique, Internal Oblique, and Transversus Abdominis) were characterized. The parameters obtained for each muscle were incorporated into a finite strain formulation to simulate active behavior of muscles incorporating the anisotropy of the tissue. The results show the potential of the model to predict the anisotropic behavior of the tissue associated to fibers and how this influences on the strain, stress and generated force during an isometric contraction

Perfil de casos de tuberculose notificados e fatores associados ao abandono, Belo Horizonte, MG

OBJECTIVE: To describe the profile of notified tuberculosis cases and analyze the factors associated with treatment dropout. METHODS: A total of 178 cases of tuberculosis notified in the western region of Belo Horizonte (Southeastern Brazil) in 2001 and 2002 and recorded in the National System for Notifiable Diseases were described. An unmatched case-control study was conducted, with data collected by means of interviews, to compare patients who dropped out of treatment with those who achieved cure. The following variables were analyzed: sociodemographic and behavioral characteristics, associations with AIDS, side effects, information on the disease and interest in treatment. Univariate analysis and unconditional logistic regression for multivariate analysis were used. Adjusted odds ratios with 95% confidence limits were used as the measurement for associations. RESULTS: The coefficient of incidence was 56.6/100,000 inhabitants. There was predominance of men aged 30 to 49 years and of the pulmonary form (76.4%) and bacillary form (72.5%). Among the notified cases, 65.2% achieved cure, 12.4% dropped out of treatment and 9.6% died. Treatment location had no influence on the results. In the case-control study, there was no difference regarding gender, color, schooling, income, occupation, family support, association with AIDS and alcohol consumption. The use of drugs, interest in treatment and information about the disease were shown to be independently associated with dropout. CONCLUSIONS: Adherence to treatment is a challenge in controlling tuberculosis. The protection factors (interest in treatment and information about the disease) and recognition that drug use is a risk factor must form part of the strategies for patient care in order to reduce dropout rates and restore health.OBJETIVO: Descrever o perfil dos casos notificados de tuberculose e analisar os fatores associados ao abandono do tratamento. MÉTODOS: Foram descritos 178 casos de tuberculose notificados na Regional Oeste de Belo Horizonte, em 2001-2002, e registrados no Sistema Nacional de Agravos de Notificação. Realizou-se estudo caso-controle não pareado, com dados coletados por entrevistas, comparando pacientes que abandonaram o tratamento com aqueles que evoluíram para cura. Foram analisadas as variáveis: características sociodemográficas, comportamentais, associação com Aids, efeitos colaterais, informação sobre a doença e interesse no tratamento. Utilizou-se análise univariada e regressão logística não condicional na análise multivariada, com odds ratio ajustado como medida de associação e intervalo de confiança de 95%. RESULTADOS: O coeficiente de incidência foi de 56,6/100.000 habitantes. Houve predomínio de homens, de 30 a 49 anos, da forma pulmonar (76,4%), e 72,5% de bacilíferos. Entre as notificações verificou-se 65,2% de curas, 12,4% abandonos e 9,6% óbitos, sem influência do local do tratamento. No estudo caso-controle não houve diferença quanto ao gênero, cor, escolaridade, renda, ocupação, apoio familiar, associação com Aids e etilismo. O uso de drogas, interesse em se tratar e informação sobre a doença mostraram-se independentemente associados ao abandono. CONCLUSÕES: A adesão ao tratamento representa um desafio no controle da tuberculose. Os fatores de proteção - interesse em se tratar e nível de informação sobre a doença - e o reconhecimento do uso de droga como fator de risco devem integrar estratégias de cuidado ao doente, buscando reduzir os índices de abandono para recuperação da saúde

En torno a la correspondencia internacional de Zoel García de Galdeano

In this work we present progress regarding the study of the intense epistolary activity between Zoel García de Galdeano and some of the most important foreign mathematicians of his time. In particular, we list all the letters known up to date, we provide a general overview of them, and we perform a more detailed content analysis of some of them.En este trabajo presentamos avances relacionados con el estudio de la intensa actividad epistolar de Zoel García de Galdeano con destacados matemáticos extranjeros de su época. En particular aportamos un listado y una revisión general de todas las cartas localizadas hasta el momento y abordamos un estudio más detallado del contenido de algunas de ellas