Photothermal deflection determination of iron(II) with ferrozine with sorption preconcentration on silufol plates

Photothermal deflection spectroscopy was applied to the selective detection of iron(II) chelate with ferrozine by its sorption preconcentration on Silufol plates. The linearity range was 1 × 10-11-6 × 10 -8 mol cm-2 of chelate at the plate surface, which corresponded to 1 × 10-9 × 10-6 M of chelate in solution. The limits of detection and quantification are 8 × 10 -12 and 2.5 × 10-11 mol cm-2 at the plate from 15 μL of test solution (0.5 nM and 1.5 nM in solution, respectively), and the absolute detection limit is 8 fmol in the whole spot applied to a plate. Characteristics and features of photothermal deflection detection are discussed. © 2008 Society for Applied Spectroscopy

Determination of Thermal Diffusivity of Ceramics by Means of Photothermal Beam Deflection

The non-contact and non-destructive photothermal beam deflection (PBD) method has been used for the characterization of the thermal properties of Alumina (Al2O3), Mullite (3Al2O3·2SiO2) and Oxidic-Bonded Silicon Carbide (OBSiC) samples often used in chemical engineering. Measurements of thermal diffusivity κ have been performed. One obtains κ = 7.96 ⋅10$^{-6}$ m²/s for Alumina, κ =1.94 ⋅10$^{-6}$(m² )/s for Mullite and κ = 3.91⋅10$^{-6}$(m² )/s for OBSiC

Local-scale nutrient regeneration facilitates seaweed growth on wave-exposed rocky shores in an upwelling system

Abstract This study shows that, even on exposed, wave-swept, rocky shores in a nutrient-replete upwelling ecosystem, mussels (Mytilus californianus) facilitate the growth of the seaweed Porphyra perforata by enhancing nutrient concentrations in the nearby water column. In field surveys on emergent substrate in the mid-intertidal zone, we found ten times greater abundance of P. perforata on mussels than on adjacent rock. In field experiments, P. perforata accumulated and grew more quickly on mussels than on bare rock or on mussel mimics, suggesting that nutrients excreted by mussels might be responsible for greater P. perforata cover. At high tide, water column ammonium concentrations over mussel beds were nearly double those found over bare rock. Correspondingly, tissue nitrogen concentrations were higher, and carbon-to-nitrogen ratios were lower in P. perforata growing on mussels compared to bare rock. Given the dominance of mussels in mid-intertidal regions of temperate coasts worldwide, ammonium regeneration could be a general contributor to local-scale nutrient availability, even in high-flow systems characterized by high nutrient concentrations

Hallux Rigidus de grado medio : nuestra técnica quirúrgica de elección

Hallux rigidus is the result of a degenerative process of the metatarsophalangeal joint of the hallux. In the intermediate stages there are controversies in the type of treatments and different types of osteotomies can be performed. Objective. To analyze cases of moderate grade hallux rigidus that have undergone surgery at out center with a chevron-type modified osteotomy. Material and methods. We conducted a retrospective study between January 2013 and December 2015 of 21 hallux rigidus with a minimum follow-up of 12 months. To evaluate the results we used the AOFAS questionnaire and the visual analogue scale (VAS). At the end of the follow-up we also conducted a satisfaction questionnaire. Results. The postoperative results show a considerable increase in the average mean of the AOFAS questionnaire from 61,3 before surgery to 92,1 at 12 months after surgery. The VAS improved 6 points and 18 patients were very satisfied with the results. There were no cases of nonunion, avascular necrosis, MTF stiffness, failed implants or infection. No patient was reoperated. Conclusion. We believe that our technique can be useful nowadays. This technique is easy to perform and reproducibl

Artrodesis subtalar primaria como tratamiento de fracturas conminutas de calcáneo Sanders tipo IV

Las fracturas conminutas Sanders IV de calcáneo dan lugar, en la mayoría de los casos, a una artrosis subtalar postraumática dolorosa e incapacitante, que en muchas ocasiones, requiere una artrodesis subtalar secundaria. Esta artrodesis puede ser técnicamente compleja, ya que no se trata de una fijación in situ, sino que requiere la realización de osteotomías de corrección a nivel del cuerpo del calcáneo en la misma cirugía.Material y métodos. Presentamos 4 pacientes con fracturas conminutas de calcáneo Sanders tipo IV que fueron tratadas mediante una artrodesis subtalar primaria con reconstrucción concomitante del cuerpo del calcáneo. El seguimiento medio fue de 15 meses. Resultados. Obtuvimos la consolidación ósea, tanto de la artrodesis como de la fractura, alrededor de los 4 meses, sin existir signos de artrosis en otras articulaciones. No hubo ninguna complicación de herida quirúrgica, ni aparecieron otras complicaciones típicas de estas lesiones, como impingement de peroneos, problemas con el calzado o bloqueo o degeneración de la articulación tibio talar durante el seguimiento. La puntuación AOFAS media a los 12 meses fue de 78. Conclusiones. La artrodesis subtalar primaria con la corrección inicial de las deformidades asociadas en el cuerpo del calcáneo (acortamiento, ensanchamiento y varo) evita complicaciones posteriores y obtiene buenos resultados

Acute kidney injury is associated with subsequent infection in neonates after the Norwood procedure: a retrospective chart review

Background: Acute kidney injury (AKI) and infection are common complications after pediatric cardiac surgery. No pediatric study has evaluated for an association between postoperative AKI and infection. The objective of this study was to determine if AKI in neonates after cardiopulmonary bypass was associated with the development of a postoperative infection. Methods: We performed a single center retrospective chart review from January 2009 to December 2015 of neonates (age ≤ 30 days) undergoing the Norwood procedure. AKI was defined by the modified neonatal Kidney Disease Improving Global outcomes serum creatinine criteria using (1) measured serum creatinine and (2) creatinine corrected for fluid balance on postoperative days 1-4. Infection, (culture positive or presumed), must have occurred after a diagnosis of AKI and within 60 days of surgery. Results: Ninety-five patients were included, of which postoperative infection occurred in 42 (44%). AKI occurred in 38 (40%) and 42 (44%) patients by measured serum creatinine and fluid overload corrected creatinine, respectively, and was most commonly diagnosed on postoperative day 2. The median time to infection from the time of surgery and AKI was 7 days (IQR 5-14 days) and 6 days (IQR 3-13 days), respectively. After adjusting for confounders, the odds of a postoperative infection were 3.64 times greater in patients with fluid corrected AKI (95% CI, 1.36-9.75; p = 0.01). Conclusions: Fluid corrected AKI was independently associated with the development of a postoperative infection. These findings support the notion that AKI is an immunosuppressed state that increases the risk of infection

Cross-Sectional Study of Sleep Quantity and Quality and Amnestic and Non-Amnestic Cognitive Function in an Ageing Population: The English Longitudinal Study of Ageing (ELSA)

Background The aim was to investigate the association between sleep disturbances and cognitive function in younger and older individuals from an ageing population. Methods 3,968 male and 4,821 female white participants, aged 50 years and over, from the English Longitudinal Study of Ageing (ELSA) were studied. Information on sleep quality and quantity as well as both amnestic (memory, ACF) and non-amnestic (non-memory, nACF) function was available at Wave 4 (2008). Analysis of covariance was used to evaluate the relationship between sleep and cognitive function. Results After adjustment for multiple confounders in the younger group (50–64 years) duration of sleep explained 15.2% of the variance in ACF (p = 0.003) and 20.6% of nACF (p = 0.010). In the older group (65+ years) the estimates were 21.3% (p<0.001) and 25.6% (p<0.001), respectively. For sleep quality, there was a statistically significant association between sleep quality and both ACF (p<0.001) and nACF (p<0.001) in the older age group, but not in the younger age group (p = 0.586 and p = 0.373, respectively; interaction between age and sleep quality in the study sample including both age groups: p<0.001 for ACF and p = 0.018 for nACF). Sleep quality explained between 15.1% and 25.5% of the variance in cognition. The interaction with age was independent of duration of sleep. At any level of sleep duration there was a steeper association between sleep quality and ACF in the older than the younger group. Conclusions The associations between sleep disturbances and cognitive function vary between younger and older adults. Prospective studies will determine the temporal relationships between sleep disturbances and changes in cognition in different age groups

Relation between body mass index and depression: a structural equation modeling approach

<p>Abstract</p> <p>Background</p> <p>Obesity and depression are two major diseases which are associated with many other health problems such as hypertension, dyslipidemia, diabetes mellitus, coronary heart disease, stroke, myocardial infarction, heart failure in patients with systolic hypertension, low bone mineral density and increased mortality. Both diseases share common health complications but there are inconsistent findings concerning the relationship between obesity and depression. In this work we used the <it>structural equation modeling </it>(SEM) technique to examine the relation between body mass index (BMI), as a proxy for obesity, and depression using the Canadian Community Health Survey, Cycle 1.2.</p> <p>Methods</p> <p>In this SEM model we postulate that 1) BMI and depression are directly related, 2) BMI is directly affected by the physical activity and, 3)depression is directly influenced by stress. SEM was also used to assess the relation between BMI and depression separately for males and females.</p> <p>Results</p> <p>The results indicate that higher BMI is associated with more severe form of depression. On the other hand, the more severe form of depression may result in less weight gain. However, the association between depression and BMI is gender dependent. In males, the higher BMI may result in a more severe form of depression while in females the relation may not be the same. Also, there was a negative relationship between physical activity and BMI.</p> <p>Conclusion</p> <p>In general, use of SEM method showed that the two major diseases, obesity and depression, are associated but the form of the relation is different among males and females. More research is necessary to further understand the complexity of the relationship between obesity and depression. It also demonstrated that SEM is a feasible technique for modeling the relation between obesity and depression.</p