•Nanostructured platinum thin films are prepared by Magnetron Sputtering.•The thin film (ca. 280nm) is highly porous and formed by tilted nanocolumns.•Cholesterol oxidase is covalently immobilized ...using polydopamine.•Cholesterol biosensor exhibits excellent sensitivity, selectivity and stability.
This paper reports a novel cholesterol biosensor based on nanostructured platinum (Pt) thin films prepared by Magnetron Sputtering (MS) in an oblique angle (OAD) configuration. Pt thin films were deposited onto a gold screen-printed electrode and characterized using Rutherford Back Scattering (RBS), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), Cyclic Voltammetry (CV), X-ray Photo-electron Spectroscopy (XPS), Atomic Force Microscopy (AFM) and wetting analysis. Our results confirmed that the film is highly porous and formed by tilted nanocolumns, with an inclination of around 40° and a total thickness of 280nm. XRD and CV analysis confirmed the polycrystalline nature of the Pt thin film. Cholesterol oxidase (ChOx) was covalently immobilized using a bioinspired polymer, polydopamine (PDA), via Schiff base formation and Michael-type addition. After being immobilized, ChOx displayed apparent activation energy of 34.09kJmol−1 and Michaelis constant (KM) values of 34.09kJmol−1 and 3.65mM, respectively, confirming the high affinity between ChOx and cholesterol and the excellent ability of the PDA film for immobilizing biological material without degradation. Under optimized working conditions the developed biosensor presented a sensitivity of 14.3mAM−1cm−2 (R2:0.999) with a linear range up to 0.5mM and a limit of detection of 10.5μM (S/N=3). Furthermore, the biosensor exhibited a fast response (<8s), good anti-interference properties and high stability after relatively long-term storage (2 months).
We investigated the temporal variation of soil bulk density (BD) in a semiarid Macrochloa tenacissima grassland where BD plays a key role in the soil–plant feedback mechanisms that are responsible ...for the patchy distribution of vegetation.
We used the core method to analyse the soil BD in two experimental sites in microsites that were representative of the spatial heterogeneity of soils and vegetation. The study was performed over two years, in winter (three times) and summer (twice). We studied the changes in BD in relation to the rainfall and to the soil properties that describe or affect the soil structural conditions, such as soil moisture, particle-size, clay mineralogy, the contents of various organic carbon fractions and certain microaggregation indices.
We found a consistent temporal variation in BD, which was lower in winter (1.22±0.02g/cm3, average±SEM) than in summer (1.33±0.02g/cm3) and depended on the rainfall in the weeks before sampling. The greatest change was observed during the first year of study, when the wettest winter and the driest summer occurred. The variation of BD was most pronounced in the mounds developed under senescent plants (+16.7% average increase from winter to summer), intermediate under adult plants and in the residual mounds (+8.9%) and was weak in the soils of the bare areas or under young plants (+5.1%). This implies that the microtopography should get steeper in winter and flatter in summer. The largest changes in BD were correlated with variables representing organic matter and its action in adhering soil particles.
We observed consistent temporal variations in BD that were spatially heterogeneous and related to wet conditions in the soils studied. Research is needed to establish the mechanisms responsible for the changes in BD, which may include greater activity of roots and fauna during the wet season and the enrichment in labile organic fractions that are hygroscopic and can bind soil particles into temporary aggregates.
Spatially heterogeneous temporal variation in BD must be taken into account in inventories of soil nutrients, water or carbon. Moreover, it implies an increased porosity under vegetated patches just when the soil receives the most rainfall, resulting in a positive feedback of plant growth and mound formation. This mechanism might be added to those already described for plant–soil feedbacks in dry lands.
•We studied soil bulk density in microsites representing the soil heterogeneity.•Consistent temporal variations were observed related to moisture conditions.•Density change was spatially heterogeneous, with bare areas showing less variation.•Variation was correlated with coarse fragments, labile carbon and microaggregation.
Equilibrium swelling is a feasible and simple experiment to determine the cross-link density of networks. It is the most popular and useful approach; however, in most of the cases, the given values ...are highly uncertain if not erroneous. The description of the complex thermodynamics of swollen polymer networks is usually based on the Flory−Rehner model. However, experimental evidence has shown that both the mixing term described by the Flory−Huggins expression and the elastic component derived from the affine model are only approximations that fail in the description and prediction of the rubber network behavior. This means that the Flory−Rehner treatment can only give a qualitative evaluation of cross-link density because of its strong dependence on the thermodynamic model. In this work, the uncertainties in the determination of the cross-link density in rubber materials by swelling experiments based on this model are reviewed. The implications and the validity of some of the used approximations as well as their influence in the relationship of the cross-link densities derived from swelling experiments are discussed. Importantly, swelling results are compared with results of a completely independent determination of the cross-link density by proton multiple-quantum NMR, and the correlation observed between the two methods can help to validate the thermodynamic model.
We compared the effects of two resistance training (RT) programs only differing in the repetition velocity loss allowed in each set: 20% (VL20) vs 40% (VL40) on muscle structural and functional ...adaptations. Twenty‐two young males were randomly assigned to a VL20 (n = 12) or VL40 (n = 10) group. Subjects followed an 8‐week velocity‐based RT program using the squat exercise while monitoring repetition velocity. Pre‐ and post‐training assessments included: magnetic resonance imaging, vastus lateralis biopsies for muscle cross‐sectional area (CSA) and fiber type analyses, one‐repetition maximum strength and full load‐velocity squat profile, countermovement jump (CMJ), and 20‐m sprint running. VL20 resulted in similar squat strength gains than VL40 and greater improvements in CMJ (9.5% vs 3.5%, P < 0.05), despite VL20 performing 40% fewer repetitions. Although both groups increased mean fiber CSA and whole quadriceps muscle volume, VL40 training elicited a greater hypertrophy of vastus lateralis and intermedius than VL20. Training resulted in a reduction of myosin heavy chain IIX percentage in VL40, whereas it was preserved in VL20. In conclusion, the progressive accumulation of muscle fatigue as indicated by a more pronounced repetition velocity loss appears as an important variable in the configuration of the resistance exercise stimulus as it influences functional and structural neuromuscular adaptations.
Sphingolipid (SL) metabolism is a complex biological system that produces and transforms ceramides and other molecules able to modulate other cellular processes, including survival or death pathways ...key to cell fate decisions. This signaling pathway integrates several types of stress signals, including chemotherapy, into changes in the activity of its metabolic enzymes, altering thereby the cellular composition of bioactive SLs. Therefore, the SL pathway is a promising sensor of chemosensitivity in cancer and a target hub to overcome resistance. However, there is still a gap in our understanding of how chemotherapeutic drugs can disturb the SL pathway in order to control cellular fate. We propose to bridge this gap by a systems biology approach to integrate i) a dynamic model of SL analogue (BODIPY-FL fluorescent-sphingomyelin analogue, SM-BOD) metabolism, ii) a Gaussian mixture model (GMM) of the fluorescence features to identify how the SL pathway senses the effect of chemotherapy and iii) a fuzzy logic model (FLM) to associate SL composition with cell viability by semi-quantitative rules. Altogether, this hybrid model approach was able to predict the cell viability of double experimental perturbations with chemotherapy, indicating that the SL pathway is a promising sensor to design strategies to overcome drug resistance in cancer.
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Gaia Data Release 2 Prusti, T.; Evans, D. W.; Eyer, L. ...
Astronomy and astrophysics (Berlin),
08/2018, Letnik:
616
Journal Article, Web Resource
Recenzirano
Odprti dostop
Context.
We present the second
Gaia
data release,
Gaia
DR2, consisting of astrometry, photometry, radial velocities, and information on astrophysical parameters and variability, for sources brighter ...than magnitude 21. In addition epoch astrometry and photometry are provided for a modest sample of minor planets in the solar system.
Aims.
A summary of the contents of
Gaia
DR2 is presented, accompanied by a discussion on the differences with respect to
Gaia
DR1 and an overview of the main limitations which are still present in the survey. Recommendations are made on the responsible use of
Gaia
DR2 results.
Methods.
The raw data collected with the
Gaia
instruments during the first 22 months of the mission have been processed by the
Gaia
Data Processing and Analysis Consortium (DPAC) and turned into this second data release, which represents a major advance with respect to
Gaia
DR1 in terms of completeness, performance, and richness of the data products.
Results. Gaia
DR2 contains celestial positions and the apparent brightness in
G
for approximately 1.7 billion sources. For 1.3 billion of those sources, parallaxes and proper motions are in addition available. The sample of sources for which variability information is provided is expanded to 0.5 million stars. This data release contains four new elements: broad-band colour information in the form of the apparent brightness in the
G
BP
(330–680 nm) and
G
RP
(630–1050 nm) bands is available for 1.4 billion sources; median radial velocities for some 7 million sources are presented; for between 77 and 161 million sources estimates are provided of the stellar effective temperature, extinction, reddening, and radius and luminosity; and for a pre-selected list of 14 000 minor planets in the solar system epoch astrometry and photometry are presented. Finally,
Gaia
DR2 also represents a new materialisation of the celestial reference frame in the optical, the
Gaia
-CRF2, which is the first optical reference frame based solely on extragalactic sources. There are notable changes in the photometric system and the catalogue source list with respect to
Gaia
DR1, and we stress the need to consider the two data releases as independent.
Conclusions. Gaia
DR2 represents a major achievement for the
Gaia
mission, delivering on the long standing promise to provide parallaxes and proper motions for over 1 billion stars, and representing a first step in the availability of complementary radial velocity and source astrophysical information for a sample of stars in the
Gaia
survey which covers a very substantial fraction of the volume of our galaxy.
Highlights • Motor dexterity is not the same as motor familiarity. • Higher motor dexterity scores are not related to linear increase of BOLD signal in motor areas. • Higher motor dexterity scores ...are not related to linear increase of BOLD signal in MNS. • No clear modulator effect of the MNS is observed with degree of motor dexterity.
Compared with conventional haemodialysis (HD), online haemodiafiltration (OL-HDF) achieves a more efficient removal of uraemic toxins and reduces inflammation, which could favourably affect ...nutritional status. We evaluate the effect of OL-HDF on body composition and nutritional status in prevalent high-flux HD (HF-HD) patients.
In all, 33 adults with chronic kidney disease (CKD) Stage 5 undergoing maintenance HF-HD were assigned to post-dilution OL-HDF (n = 17) or to remain on HF-HD (n = 16, control group) for 12 months. The primary outcome was the change in lean tissue mass (LTM), intracellular water (ICW) and body cell mass (BCM) assessed by multifrequency bioimpedance spectroscopy (BIS) at baseline and 4, 8 and 12 months. The rate of change in these parameters was estimated with linear mixed-effects models.
Compared with OL-HDF, patients assigned to HF-HD experienced a gradual reduction in LTM, ICW and BCM. These differences reached statistical significance at Month 12, with a relative difference of 7.31 kg 95% confidence interval (CI) 2.50-12.11; P = 0.003, 2.32 L (95% CI 0.63-4.01; P = 0.008) and 5.20 kg (95% CI 1.74-8.66; P = 0.004) for LTM, ICW and BCM, respectively. The normalized protein appearance increased in the OL-HDF group compared with the HF-HD group 0.26 g/kg/day (95% CI 0.05-0.47); P = 0.002, with a relative reduction in high-sensitive C-reactive protein -13.31 mg/dL (95% CI -24.63 to -1.98); P = 0.02 at Month 12.
OL-HDF for 1 year compared with HF-HD preserved muscle mass, increased protein intake and reduced the inflammatory state related to uraemia and dialysis, supporting the hypothesis that high convection volume can benefit nutritional status and prevent protein-energy wasting in HD patients.
Shrimp farming has experienced rising costs as a result of disease outbreaks associated with Vibrio spp. Suitable strategies for disease prevention and control are therefore urgently needed. This ...study aimed to evaluate the antimicrobial effect of Moringa oleifera seed powder against Vibrio cholerae in the rearing water of Pacific white shrimp (Penaeus vannamei) postlarvae. In vitro assays included the determination of minimum inhibitory concentration (MIC) of M. oleifera seed powder against V. cholerae, whereas in vivo assays included the effect of M. oleifera seed powder on bacterial load and water quality parameters in the rearing tanks, as well as its effect on shrimp postlarvae survival. M. oleifera seed powder inhibited the growth of V. cholerae with MIC values of 62·5 µg ml−1. Moreover, seawater pH of treated tanks (8·66) was significantly lower (P < 0·01) than pH of the control tanks (9·02), whereas the visibility of treated tanks (37·08 cm) was significantly higher (P < 0·01) as compared to control tanks (35·37 cm). Likewise, V. cholerae load was significantly reduced (P < 0·01) from 4·7 × 104 to 3·1 × 103 CFU per ml in tanks treated with M. oleifera seed powder. Altogether, this study demonstrates the antimicrobial activity of M. oleifera against V. cholerae in shrimp culture.
Significance and Impact of the Study:A variety of Vibrio species are responsible for crustacean mortality during their early life stages, which have caused increased costs to the aquaculture industry. Effective control strategies are, therefore, urgently needed. In this study, in vitro and in vivo assays were performed to evaluate the antimicrobial activity of Moringa oleifera seed powder in the rearing water of Pacific white shrimp (Penaeus vannamei) postlarvae. M. oleifera seed powder exhibited a low minimum inhibitory concentration against Vibrio cholerae and significantly reduced the bacterial load. These results suggest that M. oleifera may offer an environmentally friendly and cost‐effective approach to control Vibrio infections.
Traffic signs are an essential part of any circulation system, and failure detection by the driver may significantly increase the accident risk. Currently, automatic traffic sign detection systems ...still have some performance limitations, specially for achromatic signs and variable lighting conditions. In this work, we propose an automatic traffic-sign detection method capable of detecting both chromatic and achromatic signs, while taking into account rotations, scale changes, shifts, partial deformations, and shadows. The proposed system is divided into three stages: (1) segmentation of chromatic and achromatic scene elements using L⁎a⁎b⁎ and HSI spaces, where two machine learning techniques (k-Nearest Neighbors and Support Vector Machines) are benchmarked; (2) post-processing in order to discard non-interest regions, to connect fragmented signs, and to separate signs located at the same post; and (3) sign-shape classification by using Fourier Descriptors, which yield significant advantage in comparison to other contour-based methods, and subsequent shape recognition with machine learning techniques. Experiments with two databases of real-world images captured with different cameras yielded a sign detection rate of about 97% with a false alarm rate between 3% and 4%, depending on the database. Our method can be readily used for maintenance, inventory, or driver support system applications.
•We propose a complete procedure for traffic sign detection and shape classification.•It is robust against traffic sign rotations, translations, and scale variations.•It provides a good performance in a variety of circumstances (non-uniform lighting).•Our procedure yielded a good performance in experiments with real-world images.
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