274 research outputs found
Unprecedented layered coordination polymers of dithiolene group 10 metals: Magnetic and electrical properties
One-pot reactions between Ni(ii), Pd(ii) or Pt(ii) salts and 3,6-dichloro-1,2-benzenedithiol (HSC6H2Cl2SH) in KOH medium under argon lead to a series of bis-dithiolene coordination polymers. X-ray analysis shows the presence of a common square planar complex [M(SC6H2Cl2S)2]2- linked to potassium cations forming either a two-dimensional coordination polymer network for {[K2(μ-H2O)2(μ-thf)(thf)2][M(SC6H2Cl2S)2]}n [M = Ni (1) and Pd (2)] or a one-dimensional coordination polymer for {[K2(μ-H2O)2(thf)6][Pt(SC6H2Cl2S)2]}n (3). In 3 the coordination environment of the potassium ions may slightly change leading to the two-dimensional coordination polymer {[K2(μ-H2O)(μ-thf)2][Pt(SC6H2Cl2S)2]}n (4) that crystallizes together with 3. The physical characterization of compounds 1-3 show similar trends, they are diamagnetic and behave as semiconductorsWe thank financial support from MICINN (MAT2013-46753-C2-1-P, CTQ2014-52758-P and MAT2014-56143-R) and Generalitat Valenciana (PrometeoII/2014/076
Análisis de Riesgos Ocupacionales en Aserraderos.
Proyecto de Investigación.
Instituto Tecnológico de Costa Rica. Escuela de Ingeniería en Seguridad Laboral e Higiene Ambiental, Laboratorio de Higiene Analítica; Instituto Nacional de Seguros. Departamento de Gestión Empresarial en Salud Ocupacional , 2013Occupational respiratory diseases and nasal cancer are among the major work-related illnesses associated to wood dust exposure. This study will allow a systematic assessment of working conditions in the areas of safety, ergonomics and occupational exposure to chemical and biological agents in sawmills located throughout the country, in order to characterize the main risks and generate information leading to decrease the hazards in favor of the health and safety of workers.
For safety assessments checklists and questionnaires were used, photographs and videos for the ergonomic assessment using REBA and OWAS methodologies, measuring equipment for collecting samples of wood dust exposure according to the method MDHS 14/3 subsequently analyzed in the Laboratory of Analytical Hygiene and samples of biological agents according to Pouch (2003) in the Food Laboratory of the University of Costa Rica.
The results of compliance for working conditions did not exceed 60 %. For the ergonomic evaluation by REBA method, it was estimated that 95.8 % of workers (n = 92) were found above the ergonomic low risk category. By the OWAS method similar results were obtained.
The wood dust concentrations were found in a range of 0.09 to 28.9 mg/m3, with an MLE estimate of 2.33 mg/m3 exceeding national and international regulations. Species of fungi and bacteria were found in samples of wood dust: Aspergillus, Bacillum, and Penicilinum.
Is recommended to develop and implement improvement measures in all areas evaluated to prevent injuries and illnesses among sector workers, such as the implementation of safe work practices and training, among others.Las enfermedades respiratorias y el cáncer nasal se encuentran entre las afecciones ocupacionales asociadas con la exposición a polvo de madera. El presente estudio permitió valorar, de forma exploratoria, algunos agentes químicos y biológicos, condiciones de seguridad y ergonomía que podrían estar afectando la salud de los trabajadores de los aserraderos. Se utilizaron listas de verificación y cuestionarios para las evaluaciones de seguridad; fotografías y videos para la evaluación ergonómica según las metodologías REBA y OWAS; equipo de medición para la recolección de muestras de exposición a polvo de madera según el método MDHS 14/3, analizadas posteriormente en el Laboratorio de Higiene Analítica y las muestras de agentes biológicos según Pouch (2003) en el Laboratorio de Alimentos de la Universidad de Costa Rica. Los resultados de porcentaje de conformidad ponderado por empresa para las condiciones de trabajo no superaron el 60% de conformidad. Según la evaluación ergonómica a partir del método REBA, se estimó que 95,8% de los trabajadores (n=92) se encontraron sobre la categoría de riesgo ergonómico bajo. Por el método OWAS se obtuvieron resultados similares. Las concentraciones de polvo de madera se encontraron en un rango de 0,09 – 28,9 mg/m3 , con un MLE estimado de 2,33mg/m3 , superando los límites de exposición establecidos, tanto a nivel nacional como internacional. Se encontraron especies de hongos y bacterias en las muestras de polvo de madera: Aspergillus, Penicilinum y Bacillum. Se recomienda establecer medidas de mejora en todas las áreas evaluadas, para prevenir lesiones por accidentes de trabajo y enfermedades entre los colaboradores del sector, como por ejemplo la implementación de prácticas seguras de trabajo y capacitación, entre otros.Instituto Tecnológico de Costa Rica
Control and Simplicity in the Nanoprocessing of Semiconducting Copper-Iodine Double Chain Coordination Polymers
This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/abs/10.1021/acs.inorgchem.8b00364Two coordination polymers (CPs), based on Cu(I)-I double zig-zag chains bearing isonicotinic acid or 3-chloroisonicotinic acid as terminal ligands with molecular recognition capabilities, have been synthesized and fully characterized. Both compounds present extended networks with supramolecular interactions directed by the formation of H-bonds between the complementary carboxylic groups, giving supramolecular sheets. The chloro substituent allows establishing additional Cl···Cl supramolecular interactions that reinforce the stability of the supramolecular sheets. These CPs are semiconductor materials; however, the presence of chlorine produces slight changes in the I-Cu-I chains, generating a worse overlap in the Cu-I orbitals, thus determining a decrease in its electrical conductivity value. These experimental results have also been corroborated by theoretical calculations using the study of the morphology of the density of states and 3D orbital isodensities, which determine that conductivity is mostly produced through the Cu-I skeleton and is less efficient in the case of the chloro derivative compound. A fast and efficient bottom-up approach based on the self-assembly of the initial building blocks and the low solutibility of these CPs has proved very useful for the production of nanostructuresWe thank the Spanish MINECO (projects MAT2016-75883-C2-2-P, CTQ2017-87201-P, and fellowship BES-2015-071534) and the Generalitat Valenciana (PrometeoII/2014/076 project) for financial suppor
A new 3d finite element-based approach for computing cell surface tractions assuming nonlinear conditions
Advances in methods for determining the forces exerted by cells while they migrate are essential for attempting to understand important pathological processes, such as cancer or angiogenesis, among others. Precise data from three-dimensional conditions are both difficult to obtain and manipulate. For this purpose, it is critical to develop workflows in which the experiments are closely linked to the subsequent computational postprocessing. The work presented here starts from a traction force microscopy (TFM) experiment carried out on microfluidic chips, and this experiment is automatically joined to an inverse problem solver that allows us to extract the traction forces exerted by the cell from the displacements of fluorescent beads embedded in the extracellular matrix (ECM). Therefore, both the reconstruction of the cell geometry and the recovery of the ECM displacements are used to generate the inputs for the resolution of the inverse problem. The inverse problem is solved iteratively by using the finite element method under the hypothesis of finite deformations and nonlinear material formulation. Finally, after mathematical postprocessing is performed, the traction forces on the surface of the cell in the undeformed configuration are obtained. Therefore, in this work, we demonstrate the robustness of our computational-based methodology by testing it under different conditions in an extreme theoretical load problem and then by applying it to a real case based on experimental results. In summary, we have developed a new procedure that adds value to existing methodologies for solving inverse problems in 3D, mainly by allowing for large deformations and not being restricted to any particular material formulation. In addition, it automatically bridges the gap between experimental images and mechanical computations
A crystalline and free-standing silver thiocarboxylate thin-film showing high green to yellow luminescence
The simple direct synthesis of Cu(ii) and Ag(i) salts and thiobenzoic acid under ambient conditions allows the preparation of two bidimensional coordination polymers [M(TB)]n (TB = thiobenzoate; M = Cu (1) or Ag (2)). Their electrical and luminescent properties show that these are multifunctional materials. Interestingly 1 and 2 undergo a reversible solubilization process. This unusual feature and their simple preparation allow us to prepare a crystalline and free-standing thin-film of 2, using an interfacial procedure, which shows a remarkable thermochromic luminescence.This work was supported by MICINN (MAT2013-46753-C2-1-P
and CTQ2013-48635-C2-1-P) and Generalitat Valenciana (projects
PrometeoII/2014/076 and ISIC
Group 10 Metal Benzene-1,2-dithiolate Derivatives in the Synthesis of Coordination Polymers Containing Potassium Countercations
This document is the Accepted Manuscript version of a Published Work that appeared in final form in Inorganic Chemistry, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/abs/10.1021/acs.inorgchem.7b01775The use of theoretical calculations has allowed us to predict the coordination behavior of dithiolene [M(SC6H4S)2]2- (M = Ni, Pd, Pt) entities, giving rise to the first organometallic polymers {[K2(μ-H2O)2][Ni(SC6H4S)2]}n and {[K2(μ-H2O)2(thf)]2[K2(μ-H2O)2(thf)2][Pd3(SC6H4S)6]}n by one-pot reactions of the corresponding d10 metal salts, 1,2-benzenedithiolene, and KOH. The polymers are based on σ,π interactions between potassium atoms and [M(SC6H4S)2]2- (M = Ni, Pd) entities. In contrast, only σ interactions are observed when the analogous platinum derivative is used instead, yielding the coordination polymer {[K2(μ-thf)2][Pt(SC6H4S)2]}nThis work was supported in part by the MICINN (grants MAT2016-77608-C3-1-P and MAT2016-75883-C2-1-P), Generalitat Valenciana (PrometeoII/2014/076), and ISIC. J.I.M.
acknowledges financial support by the “Ramon y Cajal ́ ” Program of MINECO (RYC-2015-17730
A nanostructured Cu(II) coordination polymer based on alanine as a trifunctional mimic enzyme and efficient composite in the detection of Sphingobacteria
This research raises the potential use of coordination polymers as new useful materials in two essential research fields, allowing the obtaining of a new multiartificial enzyme with the capacity to inhibit the growth of bacteria resistance. The fine selection of the ligands allows the design of a new 2D coordination polymer (CP), with the formula [Cu2(IBA)2(OH2)4]n·6nH2O, by the combination of Cu (II) as the metal center with a pseudoamino acid (H2IBA = isophthaloyl bis β-alanine). Quantitative total X-ray fluorescence (TXRF) analyses show that the obtained CP can gradually release Cu (II) ions. Additionally, this CP can be nanoprocessed and transformed into a metal-organic gel (MOG) by using different Cu (II) salt concentrations and the application of ultrasounds. Considering its nanometric dimensions, the slow Cu (II) release and its simple processability, its performance as an artificial enzyme, and its antibacterial ability were explored. The results obtained show the first nanocoordination polymer acting as an artificial multienzyme (peroxidase, catalase, and superoxodismutase) exhibiting antibacterial activity in the presence of hydrogen peroxide, with selective behavior for three bacterium strains (S. spiritovirum, A. faecales, and B. cereus). Indeed, this CP shows a more robust inhibition capacity for Sphingobacterium. Going beyond that, as there are no comfortable and practically clinical tests capable of detecting the presence of Sphingobacteria, the compound can be easily embedded to form moldable gelatin that will facilitate the handling and low-cost commercial kit
El enclavamiento encerrojado de Grosse-Kempf en el tratamiento de las fracturas diafisarias del fémur
Se presentan 50 fracturas diafisarias de fémur tratadas mediante enclavamiento
endomedular encerrojado de Grosse-Kempf. Realizamos un estudio retrospectivo utilizando para
la valoración del resultado la escala de Thorensen, que considera la existencia de callos viciosos
radiológicos, la flexión de rodilla, la dismetría y la presencia de dolor e inflamación. El resultado
a los 20 meses del tratamiento (12-27) es excelente en 32 casos, bueno en 13, regular en 4 y
malo en 1. Creemos que este método de enclavamiento constituye un buen procedimiento para el
tratamiento de este tipo de fracturas, especialmente de las fracturas conminutas de las zonas 2, 3,
4 y 5 de Wiss. La mayoría de los resultados regulares y malos son debidos a fallos en la técnica quirúrgica.We present 50 femoral shaft fractures treated by Grosse-Kempf intramedullary
nailing. A retrospective study was performed by using the Thorensen scale for the evaluation of
results. This scale takes into account different parameters such as radiological malposition, range
of motion of the knee, shortening of the femur, pain, and swelling. Twenty months after treatment
(range: 12-27), the results were excellent in 32 cases, good in 13, fair in 4 and poor in one.
Grosse-Kempf nailing seems to be a good method for treating this type of fractures, particularly
in conminuted fractures localized in the 2, 3, 4 and 5 Wiss's zones. The majority of fair and poor
results are caused by errors in the surgical technique
Rational design of copper(II)-uracil nanoprocessed coordination polymers to improve their cytotoxic activity in biological media
This work is focused on the rational structural design of two isostructural Cu(II) nano-coordination polymers (NCPs) with uracil-1-acetic acid (UAcOH) (CP1n) and 5-fluorouracil-1-acetic acid (CP2n). Suitable single crystals for ꭕ-ray diffraction studies of CP1 and CP2 were prepared under hydrothermal conditions, enabling their structural determination as 1D-CP ladder-like polymeric structures. The control of the synthetic parameters allows their processability into water colloids based on nanoplates (CP1n and CP2n). These NCPs are stable in water at physiological pHs for long periods. However, interestingly, CP1n is chemically altered in culture media. These transformations provoke the partial release of its building blocks and the formation of new species, such as [Cu(UAcO)2(H2O)4]·2H2O (Cu(II)-complex), and species corresponding to the partial reduction of the Cu(II) centers. The cytotoxic studies of CP1n versus human pancreatic adenocarcinoma and human uveal melanoma cells show that CP1n produces a decrease in the cell viability, while their UAcOH and Cu(II)-complex are not cytotoxic under similar conditions. The copper reduction species detected in the hydrolysis of CP1n are closely related to the formation of the reactive oxygen species (ROS) detected in the cytotoxic studies. These results prompted us to prepare CP2n that was designed to improve the cytotoxicity by the substitution of UAcO by 5-FUAcO, taking into account the anticancer activity of the 5-fluorouracil moiety. The new CP2n has a similar behavior to CP1n both in water and in biological media. However, its subtle structural differences are vital in improving its cytotoxic activity. Indeed, the release during the hydrolysis of species containing the 5-fluorouracil moiety provokes a remarkable increase in cellular toxicity and a significant increase in ROS species formationThe authors thank the financial support from the Spanish
Ministerio de Economía y Competitividad (PID2019-
108028GB-C22, PID2019-108028GB-C21, MAT2016-77608-
C3-1-P, MAT2016-75883-C2-1-P, MAT2016-75883-C2-2-P,
MAT2016-75586-C4-4-P, and CTQ2017-87201-PAEI/
FEDER, UE) and the Generalidad Valenciana (Prometeo/
2019/076
Coste energético en gonartrosis y prótesis total de rodilla
Se efectúa un estudio fisiológico del ejercicio en 15 pacientes con gonartrosis no intervenida,
15 portadores de PTR modular Press-fit y 15 portadores de PTR semicostreñida Link mediante
el método de calorimetría indirecta con espirometría de circuito cerrado, comprobándose la
influencia del dolor y la marcha en el consumo de oxígeno, siendo significativamente más bajo en
los pacientes pendientes de colocación de una prótesis de rodilla y obteniendo mejor resultado clí-
nico y energético en las prótesis totales de rodilla semiconstreñidas en relación a las modulares.By mean of calorimetric indirect method with spirometry of closed circle we carry
out a physiologic study of the exercise in fifteen patients with arthritis of the knee, fifteen with total
knee arthroplasty type Press-fit and fifteen with total knee arthroplasty type endomodel of Waldemar-Link.
There was an influence of pain and gait in oxigen consume, being significantly lower
in patients with arthritis of the knee without knee arthroplasty. The best clinic and energetic results
were found in patients with knee arthroplasty type Waldemar-Link
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