Direct 3D printing of zero valent iron@polylactic acid catalyst for tetracycline degradation with magnetically inducing active persulfate.

Catalyst stability has become a challenging issue for advanced oxidation processes (AOPs). Herein, we report an alternative method based on 3D printing technology to obtain zero-valent iron polylactic acid prototypes (ZVI@PLA) in a single step and without post etching treatment. ZVI@PLA was used to activate persulfate (PS) for the removal of Tetracycline (TC) in recirculating mode under two different heating methodologies, thermal bath and contactless heating promoted by magnetic induction (MIH). The effect of both heating methodologies was systematically analysed by comparing the kinetic constant of the degradation processes. It was demonstrated that the non-contact heating of ZVI by MIH reactivates the surface of the catalyst, renewing the surface iron content exposed to the pollutant solution, which makes the ZVI@PLA catalyst reusable up to 10 cycles with no efficiency reduction. In contrast, by using a conventional thermal bath, the kinetic constant gradually decreases over the 10 cycles, because of the superficial iron consumption, being the kinetic constant 5 times lower in the 10th run compared to MIH experiment. X-ray diffraction and Mössbauer spectroscopy confirmed the presence of metallic iron embedded in the ZVI@PLA prototype, whose crystalline structure remained unchanged for 10th cycles of MIH. Moreover, it was proven that with no contact heating technology at low magnetic fields (12.2 mT), the solution temperature does not increase, but only the surface of the catalyst does. Under these superficial heated conditions, kinetic rate is increased up to 0.016 min-1 compared to the value of 0.0086 min-1 obtained for conventional heating at 20 °C. This increase is explained not only by PS activation by iron leaching but also by the contribution of ZVI in the heterogeneous activation of persulfate.

Hydride-Reduced Eu2SrFe2O6: A T-to-T' Conversion Enabling Fe2+ in Square-Planar Coordination.

Low-temperature reaction of A-site-ordered layered perovskite Eu2SrFe2O7 (T structure) with CaH2 induces a shift in the Eu2O2 slabs to form Eu2SrFe2O6 with a T' structure (I4/mmm space group) in which only the Fe cation is reduced. Contrary to the previously reported T' structures with Jahn-Teller-active d9 cations (Cu2+ and Ni+), stabilization of Eu2SrFe2O6 with the Fe2+ (d6) cation reflects the stability of the FeO4 square-planar unit. The stability of T'-type Eu2SrFe2O6 over a T-type polymorph is confirmed by density functional theory calculations, revealing the dz2 occupancy for the T' structure. Eu2SrFe2O6 has a bilayer magnetic framework with an Fe-O-Fe superexchange J∥ and an Fe-Fe direct exchange J⊥ (where J∥ > J⊥), which broadly explains the observed TN of 390-404 K. Interestingly, the magnetic moments of Eu2SrFe2O6 lie in the ab plane, in contrast to the structurally similar Sr3Fe2O4Cl2 having an out-of-plane spin alignment.

Giant direct and inverse magnetocaloric effect linked to the same forward martensitic transformation.

Metamagnetic shape memory alloys have aroused considerable attraction as potential magnetic refrigerants due to the large inverse magnetocaloric effect associated to the magnetic-field-induction of a reverse martensitic transformation (martensite to austenite). In some of these alloys, the austenite phase can be retained on cooling under high magnetic fields, being the retained phase metastable after field removing. Here, we report a giant direct magnetocaloric effect linked to the anomalous forward martensitic transformation (austenite to martensite) that the retained austenite undergoes on heating. Under moderate fields of 10 kOe, an estimated adiabatic temperature change of 9 K has been obtained, which is (in absolute value) almost twice that obtained in the conventional transformation under higher applied fields. The observation of a different sign on the temperature change associated to the same austenite to martensite transformation depending on whether it occurs on heating (retained) or on cooling is attributed to the predominance of the magnetic or the vibrational entropy terms, respectively.

[Leptospirosis frequency and socio-demographic characteristics associated in febrile patients from northern Perú]. / Frecuencia de leptospirosis y características socio-demográficas en pacientes febriles del norte del Perú.

UNLABELLED: INDRODUCTION: Leptospirosis is a frequent cause of febrile illness around the world, particularly in tropical and subtropical areas such as Perú. OBJECTIVE: To estimate the frequency and socio-demographic characteristics associated with leptospirosis in febrile patients in northern Perú. MATERIALS AND METHODS: A cross sectional study was conducted from January to December 2014 in 143 fever cases admitted to the Hospital Regional Lambayeque, Perú. Structured for socio-demographic information and sanitation questionnaire was used. Serum samples were examined to quantitatively determine the presence of IgM antibodies to leptospira using ELISA IgM. RESULTS: The frequency was 26.6% (95% CI 19.3 to 33.8) and independently associated features were: be between 20-54 years (OR: 3.36, 95% CI 1.17 to 9, 64), work in agriculture-livestock (OR: 6.15, 95% CI 1.99 to 19.05),contact with animals (OR: 4,13, IC 95%: 1,76-9,65) and consumption of unsafe water(OR: 3,33, IC 95%: 1,49-7,43). CONCLUSIONS: This study reveals a high frequency of leptospirosis among febrile patients from northern Perú. These results indicate the need to investigate routinely leptospirosis in febrile patients, especially those exhibiting risk characteristics.

Frecuencia de leptospirosis y características socio-demográficas en pacientes febriles del norte del Perú / Leptospirosis frequency and socio-demographic characteristics associated in febrile patients from northern Perú

Indroduction: Leptospirosis is a frequent cause of febrile illness around the world, particularly in tropical and subtropical areas such as Perú. Objective: To estimate the frequency and socio-demographic characteristics associated with leptospirosis in febrile patients in northern Perú. Materials and Methods: A cross sectional study was conducted from January to December 2014 in 143 fever cases admitted to the Hospital Regional Lambayeque, Perú. Structured for socio-demographic information and sanitation questionnaire was used. Serum samples were examined to quantitatively determine the presence of IgM antibodies to leptospira using ELISA IgM. Results: The frequency was 26.6% (95% CI 19.3 to 33.8) and independently associated features were: be between 20-54 years (OR: 3.36, 95% CI 1.17 to 9, 64), work in agriculture-livestock (OR: 6.15, 95% CI 1.99 to 19.05),contact with animals (OR: 4,13, IC 95%: 1,76-9,65) and consumption of unsafe water(OR: 3,33, IC 95%: 1,49-7,43). Conclusions: This study reveals a high frequency of leptospirosis among febrile patients from northern Perú. These results indicate the need to investigate routinely leptospirosis in febrile patients, especially those exhibiting risk characteristics.

Introducción: La leptopsirosis es causa frecuente de enfermedad febril alrededor del mundo, en particular en áreas tropicales y subtropicales como Perú. Objetivo. Estimar la frecuencia de leptospirosis y características socio-demográficas asociadas en pacientes febriles del norte del Perú. Material y Métodos: Se realizó un estudio transversal entre enero y diciembre de 2014 en 143 casos febriles admitidos en el Hospital Regional Lambayeque, Perú. Se usó un cuestionario estructurado para obtener información socio-demográfica y de saneamiento. Se examinaron muestras de suero para determinar cuantitativamente la presencia de anticuerpos IgM contra leptospira usando la técnica de ELISA IgM. Resultados: La frecuencia fue de 26,6% (IC 95%: 19,3-33,8) y las características asociadas independientemente fueron: tener entre 20 y 54 años (OR: 3,36, IC 95%: 1,17-9,64), dedicarse a la agricultura/ganadería (OR: 6,15, IC 95%: 1,99-19,05), el contacto con animales (OR: 4,13, IC 95%: 1,76-9,65) y el consumo de agua no potable (OR: 3,33, IC 95%: 1,49-7,43). Conclusiones: Este estudio revela una alta frecuencia de leptospirosis entre los pacientes febriles procedentes del norte del Perú. Estos resultados indican la necesidad de investigar la leptospirosis rutinariamente como causa de enfermedad febril, especialmente entre aquellos pacientes que presentan características de riesgo.

Electrical stimuli to increase cell proliferation on carbon nanotubes/mesoporous silica composites for drug delivery.

The development of smart materials as bone implants is nowadays a challenging task to optimize their fast osteointegration. Nevertheless, no attempts have been done in joining the possibility of using electrical stimulation and drug delivery together in a material intended for bone tissue engineering. Moreover, the use of this synergy to induce bone healing is still limited until novel drug reservoirs material formulations allow an efficient applicability of the electrical stimuli. Herein, we present the biological response of osteoblasts cells, cultured over carbon nanotubes-mesoporous silica composites while exposed to external electrical stimulus. Moreover, its ability to function as drug delivery systems is also demonstrated. Bone cell metabolism was stimulated and mitochondrial activity was increased up to seven times in the presence of these composites under electrical stimulus, suggesting their potential application in bone regeneration processes.

X-ray absorption and Mössbauer spectroscopies characterization of iron nanoclusters prepared by the gas aggregation technique.

Partially oxidized iron nanoclusters have been prepared by the gas-phase aggregation technique with typical sizes of 2-3 nm. This preparation technique has been reported to obtain clusters with interesting magnetic properties such as very large exchange bias. In this paper, a sample composition study carried out by Mössbauer and X-ray absorption spectroscopies is reported. The information reached by these techniques, which is based on the iron short range order, results to be an ideal way to have a characterization of the whole sample since the obtained data are an average over a very large amount of the clusters. In addition, our results indicate the presence of ferrihydrite, which is a compound typically ignored when studying this type of systems.

Lung cancer incidence in the province of Avila, Spain in 2002 and decade-long trends.

OBJECTIVES: To determine lung cancer incidence in the province of Avila, Spain, in the year 2002 and compare it with incidences reported in 2 previous studies (for 1992-1993 and 1997). PATIENTS AND METHODS: Patients diagnosed in 2002 were evaluated prospectively by the method used in the previous studies. The reference population was obtained from the municipal records for 2001. RESULTS: In 2002, 87 patients (74 men and 13 women) were diagnosed with lung cancer. The crude incidence rate was 53.09 cases per 100 000 population (men: 89.92/100 000; women: 15.93/100 000). Of these, 87.3% had been smokers. Squamous cell carcinomas were the most frequent type overall (38.1%) and in men (42.4%). Adenocarcinomas were the most frequent type in women (60%). The most frequent treatment was chemotherapy (35.6%). Between the 1992-1993 study and our 2002 study, significant increases were found in crude incidence rates of lung cancer and the use of chemotherapy, as well as significant decreases both in squamous cell carcinomas and the use of radiotherapy alone. CONCLUSIONS: Between 1992 and 2002 the lung cancer incidence in men and women in the province of Avila increased significantly.