This work presents a study on the application of wall open tubular column (WCOT) in liquid chromatography coupled with tandem mass spectrometry. Each process step reports the column preparation ...method in detail, subdivided into column pretreatment, silanization, stationary phase coating, and immobilization. Then, an evaluation of the parameters that can affect the efficiency of these columns was made. Atrazine, clomazone, and metolachlor were used as probes during this step. Factors such as stationary phase composition, length, internal diameter, stationary phase mass employed, and injection volume were investigated. In addition, with the help of Knox and Poppe graphs, the columns' performance was evaluated to determine the optimal flow rate and the speed-efficiency relationship, respectively. Based on the results, the best configurations for the WCOT column application to the LC system were defined: length-8 m; inner diameter-25 μm; mass of OV-210-2.5%
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; and, injection volume-100 nL. Finally, the optimized WCOT column developed in this work was coupled with a commercially-packed trapping column in the nano liquid chromatography system (nanoLC). In this configuration, more significant results were obtained regarding separation resolution, with Rs = 5.9 achieved for the most retained pair of analytes (clomazone and metolachlor).
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Paraoxonase‐1 (PON1) is an enzyme found in serum and follicular fluid that protects cell membrane and circulating lipids against oxidative damage. The aims of this study were to measure the ...direct effects of recombinant PON1 (rPON1) on bovine oocyte maturation at the molecular level (gene expression) and to measure the carry‐over effects of PON1 on pre‐implantation embryo development in vitro. COCs were submitted to IVM with the addition of 0.0, 0.02, 0.04 and 0.08 mg ml−1 of rPON1, corresponding to an average PON1 arylesterase enzyme activity of 2.2 ± 0.4, 15.5 ± 1.5, 30.2 ± 3.0 and 57.9 ± 5.0 U ml−1, respectively. The results indicated that addition of rPON1 during IVM improved embryo development in a dose‐dependent manner as D7 embryo development was 22.2%, 29.4%, 32.2% and 37.0% for the treatment groups, respectively (p = 0.02). In conclusion, addition of PON1 enzyme during IVM exerted dose‐related positive effects on embryo development rates to blastocysts.
The present study examined pacing site-dependent changes in QT interval and transmural dispersion of repolarization (TDR) and their potential role in the development of torsade de pointes (TdP).
In ...humans, the QT interval, JT interval, and TDR were measured in 29 patients with heart failure during right ventricular endocardial pacing (RVEndoP), biventricular pacing (BiVP), and left ventricular epicardial pacing (LVEpiP). In animal experiments, pacing site--dependent changes in ventricular repolarization were examined with a rabbit left ventricular wedge preparation in which action potentials from endocardium and epicardium could be simultaneously recorded with a transmural ECG. In humans, LVEpiP and BiVP led to significant QT and JT prolongation. LVEpiP also enhanced TDR. Frequent R-on-T extrasystoles generated by BiVP and LVEpiP but completely inhibited by RVEndoP occurred in 4 patients, of whom 1 developed multiple episodes of nonsustained polymorphic ventricular tachycardia and another suffered incessant TdP. In rabbit experiments, switching from endocardial to epicardial pacing produced a net increase in QT interval and TDR by 17+/-5 and 22+/-5 ms, respectively (n=6, P<0.01), without parallel increases in ventricular transmembrane action potential durations. Epicardial pacing facilitated transmural propagation of early afterdepolarization, leading to the development of R-on-T extrasystoles and TdP in the presence of action potential duration-prolonging agents.
LVEpiP and BiVP increase QT, JT, and TDR by altering the transmural sequence of activation of the intrinsically heterogeneous ventricular myocardium. Our data suggest that the resultant exaggeration of arrhythmic substrates can lead to the development of TdP in a subset of patients.
Climate change affects all ecosystems, but subterranean ecosystems are repeatedly neglected from political and public agendas. Cave habitats are home to unknown and endangered species, with low trait ...variability and intrinsic vulnerability to recover from human-induced disturbances. We studied the annual variability and cyclicity of temperatures in caves vis-à-vis surface in different climatic areas. We hypothesize that cave temperatures follow the average temperature pattern at the surface for each location with a slight delay in the signal, but we found three different thermal patterns occurring in caves: (1) high positive correlation and a similar thermal pattern to the surface, (2) low correlation and a slight thermal delay of the signal from the surface, and (3) high negative correlation with an extreme delay from the surface. We found daily thermal cycles in some caves, which may potentially control the circadian rhythms of cave organisms. Our results show that caves had lower thermal amplitude than the surface, and that thermal averages within caves approximately correspond to the to the annual average of surface temperature. Caves buffer external temperature and act as refugia for biota in extreme climatic events. Likewise, temperature increases at surface will lead to increment in caves, threatening subterranean biota and ecosystem services.
We present the magnetic, structural and
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Fe Mossbauer characterization of soils collected from an ancient mercury contaminated city named Huancavelica in Peru. The characterization results indicate ...that silicates and carbonates are the main mineralogical constituents in the samples. In addition,
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Fe Mössbauer spectra at room temperature reveal, the presence of two components: a magnetic component related to magnetic Fe-oxides (magnetite, hematite, goethite) and a high non-magnetic component related to Fe
+3
in high spin configuration and tetrahedral coordination in silicates. The magnetization measurements present screening of paramagnetic, ferromagnetic and antiferromagnetic signals, typical from soils containing different silicates and iron minerals. Remarkably the Verwey and Morin transitions corresponding to magnetite and hematite, respectively, are screened by the paramagnetic signal corresponding to the major silicate components in the samples. Overall, the soils are mainly composed of crystalline and amorphous silicates, calcites and iron bearing which are typical from Andean soils.
Amniocentesis is a routine procedure utilized on several species including human, equine, and bovine patients. Early assessment and discovery of new genetic traits in the cattle industry are highly ...desirable in order to accelerate genetic gain by shortening generational intervals. One of the main concerns from this procedure is the introduction of pathogenic bacterial contamination into the amniotic cavity thereby increasing the risks of spontaneous pregnancy losses post procedure. In this randomized controlled equivalence study, we have tested the effect of antimicrobial prophylaxis on the incidence of spontaneous abortions and contrasted it to untreated individuals post amniocentesis. On the treated group (n = 67) all heifers remained pregnant whereas 1 of the untreated group (n = 65) resulted in a spontaneous abortion during the study period. The latter represents 1.54% of pregnancy losses attributed to the risk associated to the amniocentesis procedure. However, the probability of inducing spontaneous abortion from the technique itself is not different to that of the contemporaneous population (n = 694) not undergoing amniocentesis viz., 1.59%. Following a two-tailed distribution, statistical analyses showed no significant differences across treatments (Fisher's exact test P = 0.49). The current prospective study indicates that performing amniocenteses on cattle have resulted in similar spontaneous pregnancy losses comparable to those of pregnant heifers without undergoing amniocentesis and regardless of antimicrobial use. In conclusion, prophylactic antimicrobials may not be applicable within the cattle amniocentesis framework.
Pepsin is one of the major enzymes with significant importance in the food industry, biomedicines, and pharmaceutical formulations. In this work, the main objective was to biochemically characterize ...a pepsin-like enzymatic extract obtained from Pygocentrus nattereri, a predatory freshwater fish, focusing on their potential industrial application. The obtained extract exhibited optimal activity at 45 °C and pH 1.0–2.0. These proteases remained stable after 2 h of incubation at temperatures ranging from 0° to 45 °C and within pH range of 1.0 to 7.0. Their activity was significantly affected in presence of pepstatin A and SDS, 10 μM and 3.46 mM respectively, while EDTA and PMSF showed partial inhibitory effects. Divalent cations (Ca2+ and Mg2+) did not inhibit the proteolytic activity of the extract; in fact, it improved at a 5 mM CaCl2 concentration. As the NaCl concentration increased, the enzyme activity decreased. However, after desalination, 90 % of the activity was recovered within the tested exposure time. Besides, this extract demonstrated exceptional versatility across diverse industrial applications, including collagen extraction augmentation, IgG hydrolysis facilitation, and silver and polyester recovery from X-ray films. Our results suggest that the obtained enzymatic extract has a wide range of potential applications.
•Pygocentrus nattereri offers fishing by-products containing high value proteins•Simple extractive method like as acid precipitation yields an acidic protease-rich extract.•The proteolytic activity exhibit by the acid extract demonstrated a remarkable pH stability range (1.0-7.0).•The extract demonstrates versatility in industrial applications, including collagen extraction, IgG hydrolysis, and recovery of silver and polyester from X-ray films.
Mating has profound physiological and behavioural consequences for female insects. During copulation, female insects typically receive not only sperm, but a complex ejaculate containing hundreds of ...proteins and other molecules from male reproductive tissues, primarily the reproductive accessory glands. The post‐mating phenotypes affected by male accessory gland (MAG) proteins include egg development, attraction to oviposition hosts, mating, attractiveness, sperm storage, feeding and lifespan. In the Mexican fruit fly, Anastrepha ludens, mating increases egg production and the latency to remating. However, previous studies have not found a clear relationship between injection of MAG products and oviposition or remating inhibition in this species. We used RNA‐seq to study gene expression in mated, unmated and MAG‐injected females to understand the potential mating‐ and MAG‐regulated genes and pathways in A. ludens. Both mating and MAG‐injection regulated transcripts and pathways related to egg development. Other transcripts regulated by mating included those with orthologs predicted to be involved in immune response, musculature and chemosensory perception, whereas those regulated by MAG‐injection were predicted to be involved in translational control, sugar regulation, diet detoxification and lifespan determination. These results suggest new phenotypes that may be influenced by seminal fluid molecules in A. ludens. Understanding these influences is critical for developing novel tools to manage A. ludens.
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