Computational Modeling of Open-Irrigated Electrodes for Radiofrequency Cardiac Ablation Including Blood Motion-Saline Flow Interaction

Radiofrequency catheter ablation (RFCA) is a routine treatment for cardiac arrhythmias. During RFCA, the electrode-tissue interface temperature should be kept below 80°C to avoid thrombus formation. Open-irrigated electrodes facilitate power delivery while keeping low temperatures around the catheter. No computational model of an open-irrigated electrode in endocardial RFCA accounting for both the saline irrigation flow and the blood motion in the cardiac chamber has been proposed yet. We present the first computational model including both effects at once. The model has been validated against existing experimental results. Computational results showed that the surface lesion width and blood temperature are affected by both the electrode design and the irrigation flow rate. Smaller surface lesion widths and blood temperatures are obtained with higher irrigation flow rate, while the lesion depth is not affected by changing the irrigation flow rate. Larger lesions are obtained with increasing power and the electrode-tissue contact. Also, larger lesions are obtained when electrode is placed horizontally. Overall, the computational findings are in close agreement with previous experimental results providing an excellent tool for future catheter research.     

First attempts to crystallize a non-homogeneous sample of thioredoxin from Litopenaeus vannamei: What to do when you have diffraction data of a protein that is not the target?

The importance of sample homogeneity and purity in protein crystallization is essential to obtain high-quality diffracting crystals. Here, in an attempt to determine the crystal structure of thioredoxin 1 from whiteleg shrimp Litopenaeus vannamei (LvTrx), we inadvertently crystallized the hexameric inorganic pyrophosphatase of Escherichia coli (E-PPase) from a non-homogeneous sample product during the initial over-expression steps and partial purification of LvTrx. The structure determination and identification of the crystallized protein were derived from several clues: the failures in the Molecular Replacement (MR) trials using LvTrx coordinates as a search model, the unit cell parameters and space group determination, and essentially by the use of the program BALBES. After using the previously deposited E-PPase structure (PDB entry 1mjw) as a search model and the correct space group assignation, the MR showed an E-PPase complexed with SO₄^?2 with small changes in the sulfate ion binding region when it compares to previously deposited E-PPases in the PDB. This work stresses the importance of protein purity to avoid the risk of crystallizing a contaminant protein or how pure need to be a protein sample in order to increase the possibility to obtain crystals, but also serves as a reminder that crystallization is by itself a purification process and how the program BALBES can be useful in the crystal structure determination of previously deposited structures in the PDB.     

Abscisic acid deficiency increases defence responses against Myzus persicae in Arabidopsis

Comparison of Arabidopsis thaliana (Arabidopsis) gene expression induced by Myzus persicae (green peach aphid) feeding, aphid saliva infiltration and abscisic acid (ABA) treatment showed a significant positive correlation. In particular, ABA‐regulated genes are over‐represented among genes that are induced by M. persicae saliva infiltration into Arabidopsis leaves. This suggests that the induction of ABA‐related gene expression could be an important component of the Arabidopsis–aphid interaction. Consistent with this hypothesis, M. persicae populations induced ABA production in wild‐type plants. Furthermore, aphid populations were smaller on Arabidopsis aba1‐1 mutants, which cannot synthesize ABA, and showed a significant preference for wild‐type plants compared with the mutant. Total free amino acids, which play an important role in aphid nutrition, were not altered in the aba1‐1 mutant line, but the levels of isoleucine (Ile) and tryptophan (Trp) were differentially affected by aphids in wild‐type and mutant plants. Recently, indole glucosinolates have been shown to promote aphid resistance in Arabidopsis. In this study, 4‐methoxyindol‐3‐ylmethylglucosinolate was more abundant in the aba1‐1 mutant than in wild‐type Arabidopsis, suggesting that the induction of ABA signals that decrease the accumulation of defence compounds may be beneficial for aphids.     

Serum ferritin as a candidate diagnostic biomarker of polycystic ovarian syndrome: a meta-analysis

Objective: In this study, we investigated about the potential of serum ferritin as a complementary diagnostic biomarker of polycystic ovarian syndrome (PCOS) by performing a meta-analysis of existing literature.

Materials and methods: Eleven studies written in English were retrieved up to 30 June 2018. Data were extracted from the selected studies by two of the authors and was subjected to statistical analysis. Levels of serum ferritin were compared between women with PCOS and controls using the standardized mean difference (SMD) and 95% confidence interval (CI). Subgroup analysis was also performed and stratified by ethnicity (Asians versus Caucasians).

Results: Overall post-outlier outcomes indicated that elevated serum ferritin is strongly associated with PCOS (SMD: 0.52; 95% CI: 0.40–0.64; P^A?=?10^?5). Subgroup analysis by ethnicity showed no significant difference between Asian and Caucasian population. Post-outlier receiving operations characteristics curve were plotted and showed that values for serum ferritin showed good potential in discriminating patients with and without PCOS (AUC?=?0.827, p?=?0.006).

Conclusion: Our findings suggest that high serum ferritin level is significantly associated with PCOS and its potential as a biomarker is evident in its high diagnostic accuracy. However, additional studies are needed to confirm our claims.     

Maize seedlings produced from dry seeds exposed to liquid nitrogen display altered levels of shikimate pathway compounds

In light of climate change and risks of food insecurity, it is becoming increasingly important to preserve plant germplasm in genebanks. Storage of seeds, particularly via cryopreservation, is one of the most proficient methods for ex situ plant germplasm conservation. Whilst seed cryo-banking can have little, to no, or even beneficial effects on subsequent seedling vigor in some species, it can lead to a number of plant abnormalities (morphological and physiological). This study investigated the effects of maize seed cryopreservation on seedling growth (until 14 d) and levels of selected amino acids produced in the shikimate pathway, a major link between primary and secondary metabolism. Seed cryopreservation reduced FW in recovered seedlings, reduced caffeic acid (2.5-fold decrease), and increased levels of all other shikimate pathway–related compounds assessed: phenylalanine (2.9-fold increase), tyrosine (2.6-fold increase), and shikimic (2.1-fold increase) and protocathecuic (3.1-fold increase) acids in cotyledons. Our results suggest that maize seed cryopreservation results in seedlings that exhibit signs of an ‘overly’ efficient and caffeic acid–deficient shikimate pathway, possibly related to their reduced growth during a highly vulnerable growth stage. However, these metabolic abnormalities manifested most severely in the maternal (cotyledonary), as opposed to vegetative (roots, stems, and leaves), tissues and hence are likely to disappear when the seedlings shed the cotyledons and become completely autotrophic.

     

Corporate and Product Carbon Footprint under Compound Hybrid Analysis: Application to a Spanish Timber Company

The European Union (EU) is advancing steadily toward the stabilization of atmospheric greenhouse gas concentrations. Various sectors are now obliged to make reductions, and new policies based on the carbon footprint are being encouraged. However, voluntary reporting of so‐called scope 3 emissions is hindering successful implementation of these policies. In this study, we present a tiered hybrid analysis to report emissions according to the ISO/TR 14069 standards and to obtain complete measures of scope 3 emissions. A process analysis for scope 1 and scope 2 emissions is complemented with a multiregional input‐output analysis for upstream scope 3 emissions. This novel approach is applied to the case study of a Spanish timber company. Its total carbon footprint in 2011 was 783,660 kilograms of carbon‐dioxide equivalent, of which 88% correspond to scope 3 emissions. These emissions are globally distributed; 71% are from European countries, followed by 8% from emerging economies (Brazil, Russia, India, Indonesia, Australia, and Turkey), 5% from China, and, finally, 16% from the rest of the world. We identify and discuss the advantages and disadvantages of this novel approach, the European implementation of which could be highly effective in reducing global carbon emissions.     

Nut consumption and weight gain in a Mediterranean cohort: The SUN study

Objective: To assess the association, in a Mediterranean population, between nut consumption and risk of weight gain (at least 5 kg) or the risk of becoming overweight/obese. Research Methods and Procedures: The Seguimiento Universidad de Navarra project is a prospective cohort of 8865 adult men and women who completed a follow‐up questionnaire after a median of 28 months. Dietary habits were assessed with a previously validated semiquantitative food‐frequency questionnaire. Results: Nine hundred thirty‐seven participants reported a weight gain of ≥5 kg at follow‐up. After adjusting for age, sex, smoking, leisure time physical activity, and other known risk factors for obesity, participants who ate nuts two or more times per week had a significantly lower risk of weight gain (odds ratio: 0.69; 95% confidence interval: 0.53 to 0.90, p for trend = 0.006) than those who never or almost never ate nuts. Participants with little nut consumption (never/almost never) gained an average of 424 grams (95% confidence interval: 102 to 746) more than frequent nut eaters. Nut consumption was not significantly associated with incident overweight/obesity in the cohort. Discussion: Frequent nut consumption was associated with a reduced risk of weight gain (5 kg or more). These results support the recommendation of nut consumption as an important component of a cardioprotective diet and also allay fears of possible weight gain.