Evaluation of different isotope dilution mass spectrometry strategies for the characterization of naturally abundant and isotopically labelled peptide standards.

Natural abundance and isotopically labelled tryptic peptides are routinely employed as standards in quantitative proteomics. The certification of the peptide content is usually carried out by amino acid analysis using isotope dilution mass spectrometry (IDMS) after the acid hydrolysis of the peptide. For the validation and traceability of the amino acid analysis procedure, expensive certified peptides must be employed. In this work we evaluate different IDMS alternatives which will reduce the amount of certified peptide required for validation of the amino acid analysis procedure. In this context, the characterization of both natural and isotopically labelled synthetic angiotensin I peptides was carried out. First, we applied a fast procedure for peptide hydrolysis based on microwave-assisted digestion and employed two certified peptide reference materials SRM 998 angiotensin I and CRM 6901-b C-peptide for validation of the hydrolysis procedure. The amino acids proline, leucine, isoleucine, valine, tyrosine, arginine and phenylalanine were evaluated for their suitability for peptide certification by IDMS by both liquid chromatography with tandem mass spectrometry (LC-MS/MS) and gas chromatography with mass spectrometry (GC)-MS/MS. Then, natural angiotensin I and 13C1-labelled angiotensin I were synthesized in-house and purified by preparative liquid chromatography. The concentration of the 13C1-labelled angiotensin I peptide was established by reverse IDMS in its native form using SRM 998 angiotensin I as reference. The concentration of the natural synthesized peptide was determined by IDMS both using the 13C1-labelled peptide in its native form and by amino acid analysis showing comparable results. Finally, the synthetic naturally abundant angiotensin I peptide was employed as "in-house" standard for the validation of subsequent peptide characterization procedures. Therefore, the novelty of this work relies on, first, the development of a faster hydrolysis procedure assisted by focused microwaves, providing complete hydrolysis in 150 min, and secondly, a validation strategy combining GC-MS and LC-MS/MS that allowed us to certify the purity of an in-house-synthesized peptide standard that can be employed as quality control in further experiments.

Correction of creatine-creatinine conversion during serum creatinine quantification by two-dimensional liquid chromatography and double-spike isotope dilution tandem mass spectrometry.

BACKGROUND AND AIMS: Development of a candidate reference method based on bidimensional liquid chromatography coupled to ESI-MS/MS and double spike isotope dilution for serum creatinine quantification capable of correcting for creatinine-creatine interconversion during sample pretreatment. Study of the impact of the creatine-creatinine interconversion during the analysis of human serum samples. MATERIALS AND METHODS: 13C1-creatinine and 13C2-creatine are added to the serum sample. Separation carried out by bidimensional liquid chromatography combining reversed phase and a strong cation exchange chromatography. The heart cut, containing creatine and creatinine, is automatically transferred to the second dimension. Quantification carried out by double spike isotope dilution tandem MS/MS. RESULTS: Minimization of spectral interferences and ion suppression due to matrix effects while increasing sample throughput compared to the direct coupling of cation exchange chromatography to the ESI source. Trueness of the method studied with the satisfactory analysis of two certified reference materials. Satisfactory intra- and inter-day precisions obtained analysing a serum pool and control sera. Analysis of 93 serum samples revealed negligible interconversions with no correlation with creatine levels. CONCLUSIONS: The method provides adequate analytical figures of merit for serum creatinine determination according to CSLI guidelines. Negligible creatine-creatinine interconversion is promoted with the applied sample preparation procedure.

How class cohesion and teachers' relatedness supportive/thwarting style relate to students' relatedness, motivation, and positive and negative outcomes in physical education.

The main goal of this study was to examine the links between class cohesion and teachers' relatedness teaching style with students' relatedness needs, motivation, and positive and negative outcomes in Physical Education. A total of 1294 students 10-18 years old (M = 14.40, SD = 1.99), 613 males (M = 14.48, SD = 1.95) and 681 females (M = 14.33, SD = 2.02), agreed to participate. They were enrolled in 88 classes belonging to 13 different primary and secondary schools in southwestern Spain. The study followed a correlational research design. Results of the multilevel path model showed a positive relationship between teachers' relatedness support and class cohesion and behavioral and emotional engagement through relatedness need satisfaction and autonomous and controlled motivation. Results also showed a positive relationship between teachers' relatedness thwarting and disruptive behaviors and problematic relationships through relatedness need frustration and amotivation. In conclusion, teachers' relatedness behaviors and class cohesion can significantly impact the students' relatedness and motivation, which in turn will affect their engagement and behaviors. A whole cascade of consequences begins with the way teachers teach and the cohesion generated in class. These first steps cannot be overlooked.

Hidatidosis primaria en la mama, una entidad poco frecuente / Breast primary hydatid cyst, a rare entity

La hidatidosis mamaria es una rara entidad, siendo excepcional su foco primario en la mama. Presentamos el caso de una mujer con una tumoración dolorosa palpable en la mama, con hallazgo de numerosos quistes en el estudio mastológico catalogados como BIRADS 3. Se realizó punción aspiración con aguja fina para citología, no concordante con los hallazgos radiológicos. Ante la persistencia de los síntomas, se realizó una exéresis quirúrgica de la lesión, con hallazgos en la biopsia compatibles con una parasitosis. Una serología positiva para Echinococcus granulosus confirmó el diagnóstico de hidatidosis, por lo que se inició el tratamiento postoperatorio con albendazol. Su evolución fue favorable, sin signos de recidiva y asintomática. Aunque poco común y en ocasiones de presentación y hallazgos inespecíficos, el quiste hidatídico debe considerarse como un diagnóstico diferencial potencialmente serio al evaluar cualquier lesión nodular en la mama en las pacientes de áreas endémicas de esta enfermedad o con factores de riesgo. (AU)

Hydatid breast disease is a rare entity, its primary focus in the breast being exceptional. We present the case of a woman with a palpable painful tumor in the breast, with the finding of numerous cysts in a mastological study, classified as BIRADS 3. FNA was performed for cytology, not consistent with radiological findings. Given the persistence of symptoms, a surgical excision of the lesion was performed, with biopsy findings compatible with parasitosis. A positive serology for Echinococcus granulosus confirmed the diagnosis of hydatidosis, for which postoperative treatment with albendazole was started. Its evolution was favorable, without signs of recurrence and asymptomatic. Although uncommon and sometimes with nonspecific presentation and findings, hydatid cyst should be considered as a potentially serious differential diagnosis when evaluating any nodular lesion in the breast in patients from endemic areas of this disease or with risk factors. (AU)

Quantification of modified nucleotides and nucleosides by isotope dilution mass spectrometry.

Epigenetic modifications are closely related to certain disorders of the organism, including the development of tumors. One of the main epigenetic modifications is the methylation of DNA cytosines, 5-methyl-2'-deoxycycytidine. Furthermore, 5-mdC can be oxidized to form three new modifications, 5-(hydroxymethyl)-2'-deoxycytidine, 5-formyl-2'-deoxycytidine, and 5-carboxy-2'-deoxycytidine. The coupling of liquid chromatography with tandem mass spectrometry has been widely used for the total determination of methylated DNA cytosines in samples of biological and clinical interest. These methods are based on the measurement of the free compounds (e.g., urine) or after complete hydrolysis of the DNA (e.g., tissues) followed by a preconcentration, derivatization, and/or clean-up step. This review highlights the main advances in the quantification of modified nucleotides and nucleosides by isotope dilution using isotopically labeled analogs combined with liquid or gas chromatography coupled to mass spectrometry reported in the last 20 years. The different possible sources of labeled compounds are indicated. Special emphasis has been placed on the different types of chromatography commonly used (reverse phase and hydrophilic interaction liquid chromatography) and the derivatization methods developed to enhance chromatographic resolution and ionization efficiency. We have also revised the application of bidimensional chromatography and indicated significant biological and clinical applications of these determinations.

Influence of Post-Processing on the Properties of Multi-Material Parts Obtained by Material Projection AM.

The great geometric complexity that additive manufacturing allows in parts, together with the possibility of combining several materials in the same part, establishes a new design and manufacturing paradigm. Despite the interest of many leading sectors, the lack of standardization still makes it necessary to carry out characterization work to enjoy these advantages in functional parts. In many of these techniques, the process does not end with the end of the machine cycle, but different post-processing must be carried out to consider the part finished. It has been found that the type of post process applied can have a similar effect on part quality as other further studied process parameters. In this work, the material projection technique was used to manufacture multi-material parts combining resins with different mechanical properties. The influence of different post-processing on the tensile behavior of these parts was analyzed. The results show the detrimental effect of ultrasonic treatment with isopropyl alcohol in the case of the more flexible resin mixtures, being advisable to use ultrasonic with mineral oil or furnace treatment. For more rigid mixtures, the furnace is the best option, although the other post-processing techniques do not significantly deteriorate their performance.

Determination of methylmercury and inorganic mercury in human hair samples of individuals from Colombian gold mining regions by double spiking isotope dilution and GC-ICP-MS.

With the aim to distinguish between routes of exposition to mercury (Hg) in artisanal and small-scale gold mining (ASGM) communities and to distinguish between Hg contamination sources, Hg species composition should be performed in human biomarkers. In this work, Hg species-specific determination were determined in human hair samples (N = 96), mostly non-directly occupied in ASGM tasks, from the six most relevant gold mining Colombian regions. Therefore, MeHg, Hg(II) and THg concentrations were simultaneously determined by double spiking species-specific isotope dilution mass spectrometry (IDMS) and GC-ICP-MS. Only 16.67% of participants were involved at some point in AGSM works and fish consumption ranged from 3 to 7 times/week, which is between medium and high intake levels. The median concentration of THg obtained from all samples is higher than the reference dose weekly acceptable of MeHg intake established by the EPA (1 ppm), whereas a 25% were more than 4 times higher than the WHO level (2.2 µg Hg g-1). Median THg value of individuals consuming fish 5-7 times per week was significantly higher (p < 0.05) than those of the other consuming groups (12.5 µg Hg g-1). Most of the samples presented a % of MeHg relative to THg higher than 80%. The average % of Hg(II)/THg was 11% and only 10 individuals presented a Hg(II) content over 30%. No significant differences (p > 0.05) were found when the amount of Hg(II) was compared between people involved in AGSM task and people not involved. Interestingly, significant differences among the evaluated groups where found when the percentage of the Hg(II)/THg ratio of these groups were compared. In fact, people involved in AGSM tasks showed 1.7 times higher Hg(II)/THg vs. inhabitants uninvolved. This suggest that Hg(II) determination by IDMS-GC-ICP-MS could be a good proxy for evaluating Hg(II) adsorption by direct exposure to mercury vapors onto hair.

Development and evaluation of an electrochemical biosensor for creatinine quantification in a drop of whole human blood.

An electrochemical biosensor for creatinine determination in a drop of whole human blood was developed and applied to the determination of creatinine in real clinical samples. It is based on the modification of a dual carbon working electrode with a combination of three enzymes: creatinine amidohydrolase (CNN), creatine amidinohydrolase (CRN) and sarcosine oxidase (SOX). Electrochemical transduction is performed using horseradish peroxidase (HRP) and potassium hexacyanoferrate(II) as mediator. A drop of human blood is enough to carry out the measurements by differential chronoamperometry where one carbon electrode detects creatine and the other both creatine and creatinine. The integrated differential signal obtained in the biosensor is linear with the concentration of creatinine in blood in the range 0.5-15 mg/dL and the enzyme-modified electrodes are stable for at least 3 months at 4 °C. The biosensor was lined to a reference method based on Isotope Dilution Mass Spectrometry (IDMS) with 50 real human blood samples and the results compared with those obtained by alternative routine techniques based on Jaffé method and an enzymatic method (Cobas 8000 Roche®, Crep2 Roche®). There were no significant differences between the creatinine concentrations found by the routine techniques and the developed biosensor.

Comparison between one and two-dimensional liquid chromatographic approaches for the determination of plasmatic stroke biomarkers by isotope dilution and tandem mass spectrometry.

This work presents the evaluation of one- and two-dimensional liquid chromatography for the quantification of three stroke outcome predictors in plasma. Isotopically labelled analogues of L-arginine (L-Arg), asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) are used to quantify the three analytes by isotope dilution and tandem mass spectrometry. Chromatographic isotope effects were not observed between natural L-Arg and its 15N-labelled analogue but they were observed between natural ADMA and SDMA and their multiple deuterated analogues. Under these conditions, bidimensional chromatography through the use of an automated multiple heart cutting mode provided unsatisfactory results for ADMA and SDMA due to the different amounts of natural and labelled compounds transferred from the first to the second chromatographic dimension. In contrast, using one dimensional liquid chromatography after a derivatization step to esterify carboxylic groups, chromatographic isotope effects did not alter the initial mass balance as full coelution of natural and labelled analogues or baseline resolution between the analytes was not required. This method was successfully validated following the Clinical & Laboratory Standards Institute guidelines and applied to the analysis of plasma samples from patients who had suffered from an intraparenchymal haemorrhagic stroke.

Effectiveness of interventions using apps to improve physical activity, sedentary behavior and diet: An umbrella review.

Technology has been recently found to be an effective tool to deliver public health interventions [1]. More specifically, the effects of interventions using apps to improve health have been targeted lately [2]. The goal of the present study was to conduct a systematic review of systematic reviews to summarize the scientific evidence. Three research questions were formulated to guide the research: RQ1. Are interventions using apps effective to improve PA? RQ2. Are interventions using apps effective to improve sedentary behavior? RQ3. Are interventions using apps effective to improve diet? This review of reviews was registered with PROSPERO (CRD42022345909). Systematic reviews were included following the PICOTS framework (population, intervention, comparator, outcomes, time and setting). In addition, reviews with several research objectives were included only when they comprised more than two-thirds of the studies analyzing one or more of the objectives of this review. As a result, 12 systematic reviews were selected for data extraction. Findings uncovered that apps could be effective to improve individuals' PA, sedentary behavior and diet. However, elements like the intervention components, the context/environment/setting, the length of the intervention or the population targeted should be carefully considered in future studies.

Invaginación sigmoidea en un adulto. ¿Está indicada la reducción endoscópica preoperatoria? / Sigmoid invagination in an adult. Is preoperative endoscopic reduction indicated?

Introducción. La invaginación intestinal o intususcepción es el deslizamiento de una parte del intestino dentro de otra adyacente. Es la causa más común de obstrucción intestinal en niños entre 3 meses y 6 años de edad, con una baja incidencia en adultos, correspondiente al 1 % del total de los cuadros obstructivos en el adulto. Su localización en colon es poco frecuente, pero conviene prestar especial atención por su asociación a lesiones malignas. Caso clínico. Varón de 39 años que acude a Urgencias con cuadro de obstrucción intestinal secundario a una invaginación en sigmoide. Se intenta reducción endoscópica, sin éxito, por lo que se indicó cirugía urgente, realizando sigmoidectomía y anastomosis colorrectal. El resultado anatomopatológico informó un adenoma de gran tamaño como causante de la invaginación. Conclusión. Existen controversias respecto al manejo endoscópico en invaginación intestinal en los adultos, especialmente en el colon, debido al elevado porcentaje de etiología tumoral maligna, recomendándose actualmente la resección en bloque sin reducción, para minimizar el riesgo de potencial siembra tumoral.

Introduction. Intestinal invagination or intussusception is the sliding of one part of the intestine into the adjacent one. It is the most common cause of intestinal obstruction in children between 3 months and 6 years of age, with a low incidence in adults, corresponding to 1% of all obstructive conditions in adults. Its location in the colon is rare, but special attention should be paid due to its association with malignant lesions. Case report. A 39-year-old male admitted to the emergency department with symptoms of intestinal obstruction secondary to a sigmoid intussusception. Endoscopic reduction was attempted, without success, so urgent surgery was indicated, performing sigmoidectomy and colorectal anastomosis. The pathology result reported a large adenoma as the cause of invagination. Conclusion. There are controversies regarding the endoscopic management of intussusception in adults, especially in the colon, due to the high percentage of malignant tumor etiology, currently recommending en bloc resection without reduction, to minimize the risk of potential tumor seeding.

Effects of Family-Based Interventions Using Mobile Apps on Youth's Physical Activity: A Systematic Review.

Objective. This review synthesized the currently available literature on the effects of family-based interventions using smartphone apps on youth physical activity. Design. Systematic review. Data Sources. 1037 studies from eight databases were retrieved. Eligibility Criteria for Selecting Studies. The seven articles included in this review met the following inclusion criteria: (1) experimental studies, (2) using smartphone apps, and (3) involving families with healthy children/adolescents. Results. Studies were stratified according to whether they used smartphone apps only or the combination of sports wearables and their associated companion app. The smartphone app interventions showed significant improvements in youth's PA levels. All but one of the studies reported no significant improvement in PA levels after the intervention. However, positive PA-related outcomes were found, and the combination of sports wearables and their associated companion app showed inconclusive results due to the small number of studies. A trend of the relevance of families in improving the PA levels of youths was found. Conclusions. The findings of this review indicate that more research is needed on the effects of family-based interventions using mobile apps on youth's physical activity. Mixed results were found for variables related to the PA of the youth involved in these programs. Although strong evidence was found that youth's physical activity levels do not always improve with the implementation of these programs, promising results were found for a positive impact on different variables related to physical activity. Therefore, more experimental studies using only a mobile app to promote PA as the main outcome are needed to understand the real effect of mobile apps on youth's PA levels. Future studies need to further explore this topic by developing programs based on designs of high methodological quality.

Determination of 3-monoiodotyrosine and 3,5-diiodotyrosine in newborn urine and dried urine spots by isotope dilution tandem mass spectrometry.

High levels of 3-mono- and 3,5-diiodotyrosine (MIT and DIT, respectively) in urine have been related to iodotyrosine dehalogenase 1 deficiency, a type of congenital hypothyroidism. However, the determination of MIT and DIT in urine is not included in newborn screening programs performed in clinical laboratories to detect inborn errors of metabolism. We report here on the development of an analytical method for the determination of MIT and DIT in newborn urine and dried urine spots (DUS) by Liquid Chromatography Isotope Dilution tandem Mass Spectrometry (LC-IDMSMS). The development included the synthesis of 15N-monoiodotyrosine and 13C2-diiodotyrosine through the iodination of 15N-tyrosine and 13C2-tyrosine, respectively, using bis(pyridine)iodonium(I) tetrafluoroborate (IPy2BF4). Both labelled analogues were added at the beginning of the sample preparation procedure and used to develop both single- and double-spike LC-IDMS methods for the determination of MIT and DIT. The developed double spike methodology was able to quantify and correct possible MIT ↔ DIT interconversions throughout the sample preparation, which was observed for concentrated urine samples but not for DUS. Suppression matrix effects on the absolute signals of MIT and DIT were observed in urine samples but did not affect the IDMS results as recoveries on urine samples at different dilution factors could be considered quantitative. Method detection limits were 0.018 and 0.046 ng g-1 (limits of quantification 0.06 and 0.15 ng g-1) by single-spike IDMS, for MIT and DIT, respectively, in the analysis of urine samples and 0.07 and 0.05 ng g-1 (limits of quantification 0.23 and 0.17 ng g-1) for MIT and DIT, respectively, in the analysis of DUS. No significant differences were obtained for MIT concentrations in the analysis of the same newborn samples stored as liquid urine or DUS when the results were corrected for the creatinine content. Finally, 36 DUS samples from healthy newborns were analyzed and MIT was detected in all samples at low ng mg-1creatinine levels.

Androgen-Dependent Prostate Cancer Cells Reprogram Their Metabolic Signature upon GLUT1 Upregulation by Manganese Superoxide Dismutase.

Prostate cancer is the second leading cause of cancer in men across the globe. The prostate gland accounts for some unique glycolytic metabolic characteristics, which causes the metabolic features of prostate tumor initiation and progression to remain poorly characterized. The mitochondrial superoxide dismutase (SOD2) is one of the major redox metabolism regulators. This study points out SOD2 as one major regulator for both redox and glycolytic metabolism in prostate cancer. SOD2 overexpression increases glucose transporter GLUT-1 and glucose uptake. This is not an insulin-mediated effect and seems to be sex-dependent, being present in male mice only. This event concurs with a series of substantial metabolic rearrangements at cytoplasmic and mitochondrial level. A concomitant decrease in glycolytic and pentose phosphate activity, and an increase in electron transfer in the mitochondrial electronic chain, were observed. The Krebs Cycle is altered to produce amino-acid intermediates by decreasing succinate dehydrogenase. This in turn generates a 13-fold increase in the oncometabolite succinate. The protein energy sensor AMPK is decreased at basal and phosphorylated levels in response to glucose deprivation. Finally, preliminary results in prostate cancer patients indicate that glandular areas presenting high levels of SOD2 show a very strong correlation with GLUT-1 protein levels (R2 = 0.287 p-value < 0.0001), indicating that in patients there may exist an analogous phenomenon to those observed in cell culture and mice.

Evaluation of different internal standardization approaches for the quantification of melatonin in cell culture samples by multiple heart-cutting two dimensional liquid chromatography tandem mass spectrometry.

We evaluate here different analytical strategies for the chromatographic separation and determination of N-acetyl-5-methoxytryptamine (MEL) and its oxidative metabolites N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK), N1-acetyl-5-methoxykynuramine (AMK) and cyclic 3-hydroxymelatonin (c3OHM) in cell culture samples. Two dimensional liquid chromatography (2D-LC) in the multiple heart-cutting mode was compared with regular 1D chromatographic separations of MEL and its oxidative metabolites. Our results showed that the use of trifluoroacetic acid (TFA) as mobile phase modifier was required to obtain a satisfactory resolution and peak shapes particularly for c3OHM. As TFA is not compatible with ESI ionization the application of the MHC mode was mandatory for a proper chromatographic separation. We evaluate also different internal standardization approaches based on the combined use of a surrogate standard (5-methoxytryptophol) and an internal standard (6-methoxytryptamine) for MEL quantification in cell culture samples obtaining unsatisfactory results both by 1D- and 2D-LC-ESI-MS/MS (from 9 ± 2 to 186 ± 38%). We demonstrate that only the application of isotope dilution Mass Spectrometry through the use of an in house synthesized 13C isotopically labelled analogue provided quantitative MEL recoveries both by using 1D- and 2D-LC-ESI-MS/MS (99±1 and 98±1. Respectively) in androgen-insensitive human prostate carcinoma PC3 cells.

Multiple heart-cutting two dimensional liquid chromatography and isotope dilution tandem mass spectrometry for the absolute quantification of proteins in human serum.

We evaluate here the combination of two-dimensional liquid chromatography (2D-LC) in the multiple heart cutting mode and isotope dilution tandem mass spectrometry for the direct analysis of tryptic digests of serum samples. As a proof of concept, we attempt the quantification of proteotypic peptides of Apolipoprotein AIV (APOA4), Complement C3 (C3) and Vitronectin (VTN) which have been previously identified as potential candidate biomarkers of glaucoma. Using this 2D-LC strategy, analyte enrichment steps are avoided and the sample preparation involved after enzymatic digestion amounted to a simple centrifugation, evaporation of the supernatant and reconstitution in the 1D mobile phase. A mobile phase not compatible with the ESI source (10 mM KH2PO4 at pH 2.7) was used in the first dimension as it provided a satisfactory chromatographic resolution of the peptides and a high buffering capacity avoiding changes in retention times when analyzing complex matrices like human serum. We also demonstrate that using coeluting labelled analogues of the target peptides, protein concentrations were not affected by slight retention time shifts affecting the amount of target peptides transferred to the second dimension. Satisfactory results were obtained when analyzing fortified serum samples (recoveries from 98 to 113%). Precisions in the range of 1-9% RSD were obtained when replicating the analysis of a pooled serum sample. The comparative analysis of serum samples from n = 94 control subjects and n = 91 patients diagnosed with primary open-angle glaucoma did not show significant differences in the APOA4, VTN and C3 concentrations in contrast with previous studies using immunoassays.

Comprehensive Isotope Ratio Metabolomics: Gas chromatography Isotope Ratio Mass Spectrometry of urinary metabolites and exhaled breath.

We have developed an analytical procedure to measure the carbon isotopic composition of multiple compounds even when there is a partial overlap in the chromatographic profiles and applied this procedure to measure the carbon isotopic composition of different metabolites in human urine and exhaled breath. Method development and validation was performed with CRM IAEA-600 caffeine after calibration of the reference CO2 gas using a mixture of certified undecane, pentadecane and eicosane δ(13C) standards. The alternative data treatment procedure included the correction of time-lag between Faraday cup amplifiers (44 ms at mass 45 and -160 ms at mass 46), the calculation and correction of chromatographic isotope effects on each peak (isotope shifts) and the calculation of the isotope ratio for each compound using the linear regression slope procedure with data only at the top of the chromatographic peak. In that way, partial chromatographic overlap between different metabolites can be tolerated (resolution equal or higher than 1). The reproducibility (SD) of the carbon isotope composition of 93 metabolites in human urine (n = 8) from one volunteer was typically better than 0.5 δ(13C) (range 0.1-2.0 δ(13C), median 0.4 δ(13C)). The method was applied to follow the carbon isotope composition of different metabolites in human urine and exhaled breath after the oral administration of 100 mg of universally labelled 13C-glucose to another human volunteer. It was demonstrated that isotopically labelled compounds could be detected in both samples even 2 h after administration. So, the developed methodology can be applied to multiple types of samples containing a large number of partially overlapping analytes including environmental applications, anti-doping control or metabolomics studies, including the use of enriched isotope tracers.

A longitudinal study on depressive symptoms and physical activity during the Spanish lockdown / Estudio longitudinal de los síntomas depresivos y la actividad física durante el confinamiento en España

Background/Objective: The aim was to evaluate the evolution of depressive symptoms and to explore the influence of physical activity (PA) practice during the home confinement due to the COVID-19 outbreak in Spain. Method: Information was collected from 595 confined participants who reported personal and contextual information, depressive symptoms and PA levels at four time points. Results: The changes in depressive symptoms were analyzed using a linear mixed model with cubic splines. Results showed a significant increase, with a significant rise between T1 and T2 (OR = 2.38, 95% CI = 1.83-3.10). It continued growing until T4 (OR = 2.93, 95% CI = 1.97-4.38). A negative relationship was observed between the increase in depressive symptoms and moderate-to-vigorous physical activity (MVPA) levels, with a significant slope up to 4 hours of MVPA per week (OR = 0.51, 95% CI = 0.29-0.90) that tended to increase until 16 hours per week of MVPA (OR = 0.41, 95% CI = 0.20-0.87). Conclusions: Results from a partition model showed that moderate intensity of PA could be enough to prevent an increase of depressive symptoms during home isolation. (AU)

Antecedentes/Objetivo: El objetivo fue evaluar la evolución de los síntomas depresivos y explorar la influencia de la práctica de actividad física (AF) durante la fase de confinamiento domiciliario de la población española como consecuencia de la enfermedad del coronavirus 2019 (COVID-19). Método: Participaron 595 personas confinadas que informaron de su situación personal, los síntomas depresivos y la AF en cuatro momentos de medida. Resultados: Los cambios en los síntomas depresivos analizados con splines cúbicos a partir de modelos lineales mixtos, mostraron un incremento significativo, con una subida importante entre el T1 y el T2 (OR=2,38, 95% CI=1,83-3,10), para luego seguir incrementándose de manera más lenta hasta el T4 (OR=2,93, 95% CI=1,97-4,38). Se observó una relación inversa entre el incremento de los síntomas depresivos y los niveles de actividad física moderada-vigorosa (AFMV) semanal, con una pendiente importante hasta las cuatro horas de AFMV a la semana (OR=0,51, 95% CI=0,29-0,90) que tiende a disminuir hasta las 16 horas/semana AFMV (OR=0,41, 95% CI=0,20-0,87). Conclusiones: Se probó un modelo de partición que mostró que la AF de intensidad moderada podría ser suficiente para prevenir un incremento de los síntomas depresivos en situación de confinamiento. (AU)

A longitudinal study on depressive symptoms and physical activity during the Spanish lockdown.

Background/Objective: The aim was to evaluate the evolution of depressive symptoms and to explore the influence of physical activity (PA) practice during the home confinement due to the COVID-19 outbreak in Spain. Method: Information was collected from 595 confined participants who reported personal and contextual information, depressive symptoms and PA levels at four time points. Results: The changes in depressive symptoms were analyzed using a linear mixed model with cubic splines. Results showed a significant increase, with a significant rise between T1 and T2 (OR = 2.38, 95% CI = 1.83-3.10). It continued growing until T4 (OR = 2.93, 95% CI = 1.97-4.38). A negative relationship was observed between the increase in depressive symptoms and moderate-to-vigorous physical activity (MVPA) levels, with a significant slope up to 4 hours of MVPA per week (OR = 0.51, 95% CI = 0.29-0.90) that tended to increase until 16 hours per week of MVPA (OR = 0.41, 95% CI = 0.20-0.87). Conclusions: Results from a partition model showed that moderate intensity of PA could be enough to prevent an increase of depressive symptoms during home isolation.

Antecedentes/Objetivo: El objetivo fue evaluar la evolución de los síntomas depresivos y explorar la influencia de la práctica de actividad física (AF) durante la fase de confinamiento domiciliario de la población española como consecuencia de la enfermedad del coronavirus 2019 (COVID-19). Método: Participaron 595 personas confinadas que informaron de su situación personal, los síntomas depresivos y la AF en cuatro momentos de medida. Resultados: Los cambios en los síntomas depresivos analizados con splines cúbicos a partir de modelos lineales mixtos, mostraron un incremento significativo, con una subida importante entre el T1 y el T2 (OR = 2,38, 95% CI = 1,83-3,10), para luego seguir incrementándose de manera más lenta hasta el T4 (OR = 2,93, 95% CI = 1,97-4,38). Se observó una relación inversa entre el incremento de los síntomas depresivos y los niveles de actividad física moderada-vigorosa (AFMV) semanal, con una pendiente importante hasta las cuatro horas de AFMV a la semana (OR = 0,51, 95% CI = 0,29-0,90) que tiende a disminuir hasta las 16 horas/semana AFMV (OR = 0,41, 95% CI = 0,20-0,87). Conclusiones: Se probó un modelo de partición que mostró que la AF de intensidad moderada podría ser suficiente para prevenir un incremento de los síntomas depresivos en situación de confinamiento.

Towards Functional Parts by Binder Jetting Calcium-Sulphate with Thermal Treatment Post-Processing.

The objective of our research is to improve the properties of calcium-sulphate hemihydrate parts printed by binder jetting. In this paper, we show the thermal treatment results when using temperature time ramps on binder-jetted ceramic parts without infiltrating. The results show that the mechanical properties of printed parts are improved substantially. Two different thermal cycles were investigated for their effect on the dehydration process of CaSO4·½H2O using infrared analysis. The thermal-treated samples were compared with respect to porosity, surface roughness, compression strength and dimensional and weight variation. The proposed thermal treatment significantly improves the compression strength in a short time, guaranteeing dimensional stability while providing a good surface. This improvement in mechanical properties offers a great chance for using binder-jetted parts as functional components, for example, in the casting field or the medical sector (scaffolds).