Hormonal response during official bouldering competition.

BACKGROUND: Sports competitions present a highly stressful environment for the athletes. The stress that is produced because of physiological or psychological demands could influence athletes' performance. This study aimed to understand the dynamics of stress biomarkers during official national bouldering climbing competition. METHODS: Twelve sport climbers ([6 females] average age: 20.3±5.21 years, body height: 174.0±10.27 cm, body mass: 64.7±10.80 kg, training age: 10.3±2.40 years) took part in this study. Their saliva cortisol (C) and alpha-amylase (AA) were sampled during the official climbing competition (qualification and final). RESULTS: The results showed that C had higher values post- (qualification, 1.02±0.43 µg/dL; final, 0.46±0.27 µg/dL) than precompetition (0.45±0.24 µg/dL; 0.29±0.68 µg/dL, respectively). A similar trend can be observed in AA, with higher values post- (qualification, 156.07±133.24 U/dL; final, 199.09±51.24 U/dL) than precompetition (88.18±80.24 U/dL; 88.72±51.24 U/dL, respectively). Furthermore, C had a significantly higher response prequalification (0.45±0.24 µg/dL) than prefinal (0.29±0.19 µg/dL), with the same response post both competition rounds (qualification, 1.02±0.43 µg/dL; final, 0.46±0.27 µg/dL). CONCLUSIONS: Overall, the results showed a strong endocrine and nervous system response. These findings lead to the conclusion that sports climbing competitions present a highly stressful environment for athletes, both physically and psychologically.

Fear of falling in women: A psychological training intervention improves climbing performance.

The main purpose of this study was to determine the effect of a psychological training intervention based on emotional regulation on anxiety and climbing ability in women climbers with fear of falling. A secondary aim was to compare the outcomes of climbing ability, anxiety, self-confidence and interoceptive awareness (IA) between the psychological group (PG), a training (TG) and a control group. Self-reported climbing ability, anxiety and IA were assessed using Competitive State Anxiety Inventory-2 and the Multidimensional Assessment of Interoceptive Awareness questionnaire. Results indicated a significant improvement in climbing ability for both PG and TG. The PG showed a significant reduction in cognitive and somatic anxiety, while the TG only exhibited a reduction in cognitive anxiety. Moreover, the PG demonstrated a greater significant increase in self-confidence compared to the TG. IA improved in five subscales for the PG, whereas the TG changed in only two subscales. In conclusion, a psychological training intervention focusing on emotional regulation might contribute to improvements in IA, reduced anxiety levels, and enhancements in climbing ability and self-confidence among women climbers facing fear of falling.

Ultraviolet sun exposure and sun protection behaviors in outdoor rock climbers.

BACKGROUND: Overexposure to sunlight and sunburn are the main preventable causes of skin cancer. Outdoor sports are associated with significant levels of sunlight exposure. AIMS: We sought to quantify the sun radiation exposure received by outdoor rock climbers and assess their sun exposure habits, sun protection behaviors, attitudes, and knowledge regarding skin cancer. METHODS: From April to June 2021, outdoor rock climbers contacted via email completed an online validated self-reported questionnaire on sun related habits, behaviors, attitudes and knowledge. As a pilot trial, ten participants wore a personal dosimeter during two outdoor climbing weekends in May and November 2021. Ambient ultraviolet radiation (UVR) was also recorded. RESULTS: A total of 217 outdoor rock climbers (103 women), mean age 36.8 ± 8.8 years (range 20-70 years) and median climbing practice per week of 8 h (IQR 7.5) were studied. Two in three (65.9%) participants reported at least one sunburn event during the previous rock climbing season. Of the survey respondents, 49.3% reported using sunscreen with SPF ≥ 15, 47% wore sunglasses, and 14.3% indicated they reapplied sunscreen every two hours. The median personal UVR dose measured during the two outdoor climbing weekends analyzed was 5.2 (IQR 1.8) and 8.8 (IQR 1.1) standard erythemal doses, respectively. CONCLUSIONS: The high rates of sunburn, the elevated personal UVR measured and the clearly insufficient sun protection practices followed during rock climbing together with unsatisfactory attitudes towards tanning reveal the need to develop explicit sun protection campaigns and educational strategies to reduce the risk of skin cancer among the athletes studied.

Detection of gases and organic vapors by cellulose-based sensors.

The growing interest in the development of cost-effective, straightforward, and rapid analytical systems has found cellulose-based materials, including cellulose derivatives, cellulose-based gels, nanocellulosic materials, and the corresponding (nano)cellulose-based composites, to be valuable platforms for sensor development. The present work presents recent advances in the development of cellulose-based sensors for the determination of volatile analytes and derivatives of analytical relevance. In particular, strategies described in the literature for the fabrication and modification of cellulose-based substrates with responsive materials are summarized. In addition, selected contributions reported in the field of paper-based volatile sensors are discussed, with a particular emphasis on quick response (QR) code paper-based platforms, intelligent films for food freshness monitoring, and sensor arrays for volatile discrimination purposes. Furthermore, analytical strategies devised for the determination of ionic species by in situ generation of volatile derivatives in both paper-based analytical devices (PADs) and microfluidic PADs will also be described.

Kinetic spectrophotometric assay for the determination of vitamin C in cosmetics following ultrasound-assisted emulsification.

In this work, a new analytical approach based on ultrasound-assisted emulsification followed by a photoreaction with methylene blue (MB) and kinetic analysis by UV-vis spectrophotometry has been developed for the determination of L-ascorbic acid (AA) in cosmetic samples. The emulsification of cosmetic samples results in a transparent solution that allows an easy and rapid quantitation by UV-vis spectrophotometry. The emulsified sample is mixed with a MB aqueous solution and this mixture is subjected to irradiation with a tungsten lamp for 5 min (fixed-time kinetic assay). A reduction in the MB absorbance intensity at 664 nm occurs as the concentration of AA increases. The observed change in absorbance intensity was used for calibration and further quantitation using the relationship of absorbance logarithm vs. AA concentration (µg mL-1). In order to achieve an optimal response, different parameters involved in the reaction between AA and MB were fully investigated. Under optimal conditions, the limits of detection and quantification were 0.04 µg mL-1 and 0.15 µg mL-1, respectively. Repeatability and reproducibility, expressed as relative standard deviation, were in the range of 0.4-0.6% and 0.6-1.5%, respectively. Finally, the proposed method was applied to the analysis of 15 cosmetic samples, namely, (i) 12 samples without AA, which were used to carry out recovery studies, obtaining results in the range of 97.5-100.7%; (ii) 3 serum samples containing pure AA among their ingredients, which were used for AA stability studies.

Fluorescent paper-based sensor integrated with headspace thin-film microextraction for the detection of acyclic N-nitrosamines following in situ photocatalytic decomposition.

BACKGROUND: In this work, a novel analytical approach based on the photocatalytic decomposition of N-nitrosamines combined with headspace thin-film microextraction of the generated nitrogen oxides such as NO has been developed for the determination of the acyclic N-nitrosamine fraction in drinking water samples. A hydrophilic cellulose substrate modified with fluorescent silver nanoclusters (Ag NCs) was used both as extractant and sensing platform. A quenching effect of Ag NCs fluorescence occurs as the concentration of N-nitrosamines increases. Front-face fluorescence spectroscopy with a solid sample holder was employed for directly measuring the fluorescence quenching onto the cellulose substrate. RESULTS: In order to achieve an optimal analytical response, different parameters involved in the photocatalytic reaction as well as those concerning the microextraction step were fully investigated. It is demonstrated that the photodegradation rate of cyclic N-nitrosamines at acidic pH is much lower than that of acyclic ones, which can be the basis for the determination of the later fraction in waters. Under optimal conditions, a detection limit for the acyclic N-nitrosamine fraction around 0.08 µg L-1 using N-nitrosodimethylamine (NDMA) as model compound for calibration was obtained. Several drinking waters were spiked with acyclic N-nitrosamines showing recoveries in the range of 98-102% with a relative standard deviation of 3-4% (N = 3). SIGNIFICANCE AND NOVELTY: N-nitrosamines generated as by-products during disinfection processes applied to water cause multiple adverse effects on human health being classified as potential human carcinogens. This study highlights the suitability of a fluorescent paper-based sensor for the rapid analysis of the acyclic N-nitrosamine fraction (i.e. the most abundant fraction) as a total index in drinking water, being useful as screening tool before exhaustive chromatographic analysis, which saves costs, time and reduces waste generation.

Role of cardiorespiratory fitness on the associations between endocannabinoid system and depressive symptoms in adults diagnosed with depression: the SONRIE study / Papel de la capacidad cardiorrespiratoria en la asociación entre el sistema endocannabinoide y los síntomasdepresivos en adultos diagnosticados de depresión: el estudio SONRIE / O papel da capacidade cardiorrespiratória na associação entre o sistema endocanobinóido e os sintomasdepressivos em adultos diagnostados com a depressão: o estudo SONRIE

Objective: Endocannabinoid system (ES) seems to be altered in patients with depression. Cardiorespiratory fitness (CRF) may be an interacting factor inthe relationship between ES biomarkers and depressive symptoms in people diagnosed with depression. The aim was to study the role of CRF on thepossible association between ES biomarkers and depressive symptoms in 73 adults diagnosed with depression. Method: This study examine the outcomes of cardiorespiratory fitness and plasma levels of the lipid mediators; anandamide (AEA) and 2-arachidonoylglycerol (2-AG) sampled from 73 adults diagnosed with depression.Results: Patients with high CRF level had significant and inverse association among depressive symptoms and 2-AG serum levels ( : -0.013; 95% CI: -β: -0.013; 95% CI: -0.262 to -0.000; R²=22.6; P<0.001).Conclusions: Higher CRF levels could have a protective role on depressive symptoms by increases in 2-AG.(AU)

Objetivo: El sistema endocannabinoide (SE) parece estar alterado en pacientes con depresión. La capacidad cardiorrespiratoria (CRF) puede ser un factor que interactúe en la relación entre los biomarcadores del SE y los síntomas depresivos en personas diagnosticadas de depresión. El objetivo de este trabajo es estudiar el papel del CRF en la posible asociación entre los biomarcadores de ES y los síntomas depresivos en 73 adultos diagnosticados de depresión. Método: Este estudio examina los resultados de la aptitud cardiorrespiratoria y los niveles plasmáticos de los mediadores lipídicos; anandamida (AEA) y 2-araquidoilglicerol (2-AG) en 73 adultos diagnosticados de depresión.Resultados: Los pacientes con alto nivel de CRF tuvieron una asociación significativa e inversa entre los síntomas depresivos y los niveles séricos de 2-AG ( : -0,013; IC 95%: -0,262 a -0,000; R²=22,6; P<0,001). β: -0.013; 95% CI: -Conclusiones: Los niveles más altos de CRF podrían tener un papel protector sobre los síntomas depresivos por el aumento de 2-AG.(AU)

Objetivo: O sistema endocannabinoide (ES) parece ser alterado em doentes com depressão. A aptidão cardiorrespiratória (CRF) pode ser um factor deinteracção na relação entre os biomarcadores SE e os sintomas depressivos em pessoas diagnosticadas com depressão. O objetivo deste estudo foiestudar o papel da CRF na possível associação entre biomarcadores de ES e sintomas depressivos em 73 adultos diagnosticados com depressão. Métodos: Este estudo examina resultados de aptidão cardiorrespiratória e níveis plasmáticos de mediadores lipídicos; anandamida (AEA) e 2-arachidonoylglycerol (2-AG) em 73 adultos diagnosticados com depressão.Resultados: Os doentes com CRF elevado tinham uma associação inversa significativa entre sintomas depressivos e níveis séricos 2-AG ( : -0,013; 95%β: -0.013; 95% CI: -CI: -0,262 a -0,000; R²=22,6; P<0,001).Conclusões: Níveis mais elevados de CRF poderiam ter um papel protector nos sintomas depressivos, aumentando o 2-AG.(AU)

Covalent organic framework as adsorbent for ultrasound-assisted dispersive (micro)solid phase extraction of polycyclic synthetic fragrances from seawater followed by fluorescent determination.

In this work, a new analytical approach based on ultrasound-assisted dispersive (micro)solid phase extraction (US-D-µSPE) using TpBD-Me2 covalent organic framework (COF) as adsorbent for simple, rapid and selective fluorescent determination of two polycyclic synthetic fragrances in seawater, i.e., 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopenta-(γ)-2-benzopyran (HHCB), branded galaxolide®, and 7-acetyl-1,1,3,4,4,6-hexamethyltetralin (AHTN), branded tonalide®, is proposed. Different parameters involved in both adsorption and desorption steps were optimized in order to obtain the best results. High adsorption efficiencies in the range of 91.2-97.8% were achieved for both analytes. Desorption efficiencies of ∼98% for AHTN and HHCB were obtained using methanol as solvent, rendering the material recyclable with merely minor losses in adsorption efficiency after five consecutive cycles of adsorption/desorption. Limits of detection (LODs) were 0.082 µg L-1 and 0.070 µg L-1 for AHTN and HHCB, respectively. The proposed method was successfully applied for the analysis of seawater without the need for a previous sample treatment, e.g., pH adjustment. Recoveries in the range of 90.4-101.2% with a relative standard deviation of 5.8% were obtained for both fragrances. The results proved the great capacity of TpBD-Me2 COF for the selective sorption of polycyclic fragrances in combination with fluorescent detection, being highly promising for application to environmental monitoring of other emerging organic pollutants.

Which is the most reliable edge depth to measure maximum hanging time in sport climbers?

BACKGROUND: The ability to generate high levels of force with the finger flexor muscles and sustain it for the maximum time was reported as a climbing performance factor. This study aimed to answer the question of which is the most reliable edge depth to measure maximum hanging time in non-elite and elite rock climbers: 6, 8, 10, 12 or 14 mm. METHODS: Thirty-six climbers (10 female, 26 male; 6b-8c redpoint level) were assessed twice, one week apart. RESULTS: Systematic bias (95 % limits of agreements) was -1.84 (6.31) for HT6, -0.26 (8.83) for HT8, -1.30 (8.72) for HT10, -4.37 (9.57) for HT12, and -2.94 (9.53) for HT14 at non-elite group (all P values > 0.05 but HT12 and HT14). Among elite group, -1.38 (7.58), 0.68 (12.09), -2.20 (13.35), -0.49 (9.80) and 0.73 (10.44) was found (all P > 0.05) for HT6, HT8, HT10, HT12 and HT14, respectively. No patterns of heteroscedasticity were observed for any of the trials for non-elite and elite climbers. SIGNIFICANCE: Among all edge depths analysed, 8 mm seemed to be the most accurate edge to evaluate hanging time. Alternatively, a 10 mm hold depth could be recommended for climbers from 6b to 7c, and 12 mm for climbers from 7c+ to 8c.

Paper-Based Analytical Devices for Colorimetric and Luminescent Detection of Mercury in Waters: An Overview.

Lab-on-paper technologies, also known as paper-based analytical devices (PADs), have received increasing attention in the last years, and nowadays, their use has spread to virtually every application area, i.e., medical diagnostic, food safety, environmental monitoring, etc. Advantages inherent to on-field detection, which include avoiding sampling, sample preparation and conventional instrumentation in central labs, are undoubtedly driving many developments in this area. Heavy metals represent an important group of environmental pollutants that require strict controls due to the threat they pose to ecosystems and human health. In this overview, the development of PADs for Hg monitoring, which is considered the most toxic metal in the environment, is addressed. The main emphasis is placed on recognition elements (i.e., organic chromophores/fluorophores, plasmonic nanoparticles, inorganic quantum dots, carbon quantum dots, metal nanoclusters, etc.) employed to provide suitable selectivity and sensitivity. The performance of both microfluidic paper-based analytical devices and paper-based sensors using signal readout by colorimetry and luminescence will be discussed.

Study on the efficiency of a covalent organic framework as adsorbent for the screening of pharmaceuticals in estuary waters.

Herein, we demonstrate, for the first time, that covalent organic frameworks (COFs) can be efficient adsorbents for the screening of pharmaceuticals in real water samples, obtaining highly representative data on their occurrence and avoiding the cost of carrying high volume samples and tedious and costly clean-up and preconcentration steps. Of the 23 pharmaceuticals found present in the water samples from the Tagus river estuary using state-of-the-art solid-phase extraction (SPE), 22 were also detected (adsorbed and recovered for analysis) using a COF as the adsorbent material with adsorption efficiency of over 80% for nearly all compounds. In specific cases, acidification of the water samples was identified to lead to a dramatic loss of adsorption efficiency, underlining the effect of sample pre-treatment on the results. The COF efficiently adsorbed (>80%) 19 pharmaceuticals without acid treatment of the sample, highlighting the potential of this class of materials for representative in situ passive adsorption of pharmaceuticals, making this material suitable for being used in water monitoring programs as a simple and cost-efficient sample preparation procedure. In the case of α-hydroxyalprazolam and diclofenac, the COF outperformed the SPE procedure in the recovery efficiency. Although further efforts should be made in tailoring the desorption of the pharmaceuticals from the COF by using different solvents or solvent mixtures, we propose COFs as convenient adsorbent for broad-scope screening and as an efficient adsorbent material to target specific classes of pharmaceuticals. To the best of our knowledge, this is the first study on the use of COFs for contaminant screening in real, naturally contaminated water samples.

Performance Assessment for Rock Climbers: The International Rock Climbing Research Association Sport-Specific Test Battery.

PURPOSE: To examine the validity and reliability of a battery of 10 measures designed to assess the key physiological parameters for successful rock climbing performance. METHODS: In phase 1 of the research, an expert panel, using the Delphi method, established a 10-item test battery based on the key determinants of climbing performance. In phase 2, the tests were assessed for validity and reliability to examine their suitability as sport-specific measures of rock climbing performance. A total of 132 rock climbers, from 7 countries, volunteered to take part in the study. Each climber visited their nearest laboratory on 3 separate occasions in order to enable the required tests and retests to be completed. A minimum of 7 days was allowed between visits. RESULTS: The 10 tests established for phase 2 were designed as sport-specific measures of flexibility, strength, power, and endurance. Results indicated that, while reliable, the flexibility and strength tests were only partially successful in differentiating across climber abilities. The power and endurance tests, however, performed well with regard to validity and reliability, with the finger hang and powerslap tests being most strongly correlated with performance ability (P < .0005 to P < .002). CONCLUSION: The authors' data suggest that climbing may require a threshold level of flexibility and strength for successful performance, beyond which further improvements may not be required. In contrast, the finger hang and powerslap tests were not only reliable measures but also differentiated between climber abilities from lower grade to elite levels.

Nanomaterial-Integrated Cellulose Platforms for Optical Sensing of Trace Metals and Anionic Species in the Environment.

The development of disposable sensors that can be easily adapted to every analytical problem is currently a hot topic that is revolutionizing many areas of science and technology. The need for decentralized analytical measurements at real time is increasing for solving problems in areas such as environment pollution, medical diagnostic, food quality assurance, etc., requiring fast action. Despite some current limitations of these devices, such as insufficient detection capability at (ultra)trace level and risk of interferent effects due to matrix, they allow low-cost analysis, portability, low sample consumption, and fast response. In the last years, development of paper-based analytical devices has undergone a dramatic increase for on-site detection of toxic metal ions and other pollutants. Along with the great availability of cellulose substrates, the immobilization of receptors providing enhanced recognition ability, such as a variety of nanomaterials, has driven the design of novel sensing approaches. This review is aimed at describing and discussing the different possibilities arisen with the use of different nanoreceptors (e.g., plasmonic nanoparticles, quantum dots, carbon-based fluorescent nanoparticles, etc.) immobilized onto cellulose-based substrates for trace element detection, their advantages and shortcomings.

Change in geometric entropy with repeated ascents in rock climbing.

Lower geometric entropy (GE) could represent more economical movement in rock climbing. Repetition of a climbing route decreases energy expenditure (EE), however, association with changes in GE has not been studied. The purpose of this study was to observe changes in GE with repetition of a climbing route relative to changes in EE. Nine climbers completed nine ascents each, one week apart, on an indoor climbing structure. Digital video was recorded at 30 Hz and a marker point was digitised as an estimate of a climber's centre of mass position (CME). The displacement of CME was expressed as the length of the line of motion (LM). GE was calculated as ln((2 x LM)/CH)) where CH is the value of the convex hull about the LM. Indirect energy expenditure (EECLM) was calculated from expired air by the Weir method. Data were analysed for ascents 1 (A1), 3 (A3), 6 (A6) and 9 (A9) and compared via repeated measures ANOVA. GE was significantly different for A1 vs A6 and A9 (p < 0.05) and not different for other comparisons. GE was correlated with EECLM; r = 0.67 (p < 0.01). Climbers reduce geometric entropy with route familiarity and the lower entropy may be associated with lower energy expenditure.

Anthropometry and performance characteristics of recreational advanced to elite female rock climbers.

Despite climbing's popularity and an increasing number of female participants, there are limited anthropometric and performance data for this population. This study compares the characteristics of 55 experienced female climbers, divided into three categories (lower [ADV-L] and higher advanced [ADV-H] and elite [ELT]) based on self-reported ability. Data on climbing experience, body dimensions, body composition, flexibility, lower and upper-body power and finger strength were assessed. ELT climbers differed significantly from the ADV groups in age (Mean Difference [MD] = 8.8-9.8 yrs; despite smaller differences in years climbing MD = 1.6-2.4 yrs), greater climbing and hours training per week (MD = 3.0-3.7 h & MD = 0.9-1.6 h, respectively), and greater upper-body power (MD = 12.9-16.6 cm) and finger strength (MD = 51.6-65.4 N). Linear regression analysis showed finger strength and upper body power to be associated with ability, particularly when adjusting for descriptive and anthropometric variables (finger strength R2 = 53% and 45%; upper-body power R2 = 60% and 39% for boulder and sport, respectively). The findings support the importance of finger strength and upper-body power; changes in female anthropometric data over the last decade provide insight into the changing nature of the sport.

Covalent Organic Framework Composites: Synthesis and Analytical Applications.

In the recent years, composite materials containing covalent organic frameworks (COFs) have raised increasing interest for analytical applications. To date, various synthesis techniques have emerged that allow for the preparation of crystalline and porous COF composites with various materials. Herein, we summarize the most common methods used to gain access to crystalline COF composites with magnetic nanoparticles, other oxide materials, graphene and graphene oxide, and metal nanoparticles. Additionally, some examples of stainless steel, polymer, and metal-organic framework composites are presented. Thereafter, we discuss the use of these composites for chromatographic separation, environmental remediation, and sensing.

Attentional Differences as a Function of Rock Climbing Performance.

The purpose of this study was to investigate the relationship between attention (using two different attention tasks) and self-reported climbing ability while considering potential confounding factors (sex, age, climbing experience, and cardiorespiratory fitness) in a group of experienced climbers. Accuracy of response (AC) and reaction time (RT) from two different attention tasks using the Vienna Test System, along with self-reported on-sight and red-point climbing ability, were assessed in 35 climbers. Linear regression revealed that climbers with the highest self-reported on-sight grade had better AC during the attention task. Linear regression models revealed, after controlling for potential confounders, that AC, measured using two attention tasks, was positively related to climbers' highest self-reported on-sight climbing ability (ß = 0.388; p = 0.031). No significant differences were found between AC and self-reported red-point climbing ability (ß = 0.286; p = 0.064). No significant relationship was found between RT and climbing ability (ß = -0.102 to 0.020; p = 0.064). In conclusion, higher-level rock climbers appear to have an enhanced attention, which is related to on-sight lead climbing style, and thus, it may be an important component of climbing performance. Coaches should consider incorporating techniques to train attention based on on-sight climbing style in climbers.

A comparison of body composition assessment methods in climbers: Which is better?

OBJECTIVE: To compare body composition estimations of field estimation methods: Durnin & Womersley anthropometry (DW-ANT), bioelectrical impedance analysis (BIA) and Deborah-Kerr anthropometry (DK-ANT) against dual-energy X-ray absorptiometry (DXA) in a male Chilean sport climbing sample. METHODS: 30 adult male climbers of different performance levels participated in the study. A DXA scan (Lunar Prodigy®) was used to determine fat mass, lean mass and total bone mineral content (BMC). Total muscle mass (MM, kg) was estimated through a validated prediction model. DW-ANT and BIA ("non-athletes" and "athletes" equations) were used to determinate fat mass percentage (FM %), while DK-ANT was utilized to estimate MM and BMC. RESULTS: A significant (p<0.01) inter-method difference was observed for all methods analyzed. When compared to DXA, DW-ANT and BIA underestimated FM% and DK-ANT overestimated MM and BMC (All p<0.01). The inter-method differences was lower for DW-ANT. DISCUSSION: We found that body composition estimation in climbers is highly method dependent. If DXA is not available, DW-ANT for FM% has a lower bias of estimation than BIA in young male Chilean climbers. For MM and BMC, further studies are needed to compare and estimate the DK-ANT bias level. For both methods, correction equations for specific climbing population should be considered.

Recyclable magnetic covalent organic framework for the extraction of marine biotoxins.

A novel procedure for the preparation of magnetic covalent organic frameworks (COFs) is reported. In situ functionalization of Fe3O4 with dopamine rapidly afforded amino-functionalized magnetic nanoparticles, which after decoration with a COF building block and subsequent COF growth gave access to magnetic composite mTpBD-Me2. The optimized synthesis conditions yielded crystalline and superparamagnetic material with no loss in surface area as compared to bulk COF. The composite material was employed for the first time in magnetic solid-phase extraction of marine biotoxins from seawater with high efficiency, where calculated maximum adsorption capacities of 812 mg g-1 and 830 mg g-1 were found for okadaic acid (OA) and dinophysistoxin-1 (DTX-1), respectively, corresponding to an increase of ∼500-fold for OA and ∼300-fold for DTX-1 as compared to the commonly used non-magnetic macroporous resins. Nearly quantitative desorption efficiency of both biotoxins was obtained using 2-propanol as solvent, rendering the composite materials recyclable with merely minor losses in adsorption capacity after five consecutive cycles of adsorption/desorption. In addition, retention of crystallinity after the adsorption cycles highlights the stability of the composite in seawater. These results illustrate the great efficiency of the novel material in biotoxin adsorption and show great promise for its application in environmental monitoring programs.