Structural Characterization of Rat Galectin-5, an N-Tailed Monomeric Proto-Type-like Galectin

Galectins are multi-purpose effectors acting via interactions with distinct counterreceptors based on protein-glycan/protein recognition. These processes are emerging to involve several regions on the protein so that the availability of a detailed structural characterization of a full-length galectin is essential. We report here the first crystallographic information on the N-terminal extension of the carbohydrate recognition domain of rat galectin-5, which is precisely described as an N-tailed proto-type-like galectin. In the ligand-free protein, the three amino-acid stretch from Ser2 to Ser5 is revealed to form an extra β-strand (F0), and the residues from Thr6 to Asn12 are part of a loop protruding from strands S1 and F0. In the ligand-bound structure, amino acids Ser2–Tyr10 switch position and are aligned to the edge of the β-sandwich. Interestingly, the signal profile in our glycan array screening shows the sugar-binding site to preferentially accommodate the histo-blood-group B (type 2) tetrasaccharide and N-acetyllactosamine-based di- and oligomers. The crystal structures revealed the characteristically preformed structural organization around the central Trp77 of the CRD with involvement of the sequence signature’s amino acids in binding. Ligand binding was also characterized calorimetrically. The presented data shows that the N-terminal extension can adopt an ordered structure and shapes the hypothesis that a ligand-induced shift in the equilibrium between flexible and ordered conformers potentially acts as a molecular switch, enabling new contacts in this region.

Nanoparticles Determination by Laser Ablation Inductively Coupled Plasma Mass Spectrometry

Quantitatively studying the biodistribution and transformation of nanomaterials is of great importance for nanotoxicological evaluation. Recently, laser ablation inductively coupled plasma mass spectrometry has been employed to distinguish nanoparticles (NPs) with their dissolved ions in biological samples. The principle of the proposal is based on a hypothesis that the intact NPs sampled by laser ablation will generate discrete sharp pulses of signals in ICP-MS measurement, being totally different from the continuous, relatively lower signals generated by ions. However, it is still a controversy whether NPs could maintain their intactness during the laser ablation. This work found a way to exactly determine the number of NPs sampled for each LA-ICP-MS measurement. It made possible to reveal the signal profile of a single NP in LA-ICP-MS analysis. The results suggest that AuNR, AgNP and TIO2 NP were broken into much smaller secondary NPs during the laser ablation, therefore generating continuous signals in the analyzer. There was a certain probability that the fragmentation of large-sized NP or multiple NPs by laser ablation was not sufficient, leaving some NPs unbroken or some secondary NPs with relatively large sizes to generate discrete pulses of signals in the analyzer. When the intactness of NPs during laser ablation cannot be assured, it is impossible to determine the attribution of mass spectrum signals. These findings compromise the reliability of distinguishing NPs from their dissolved ions by LA-ICP-MS.

Altered saturation pulse with a high flip angle for venous saturation on 7 T time-of-flight magnetic resonance angiography

This study aimed to apply minimum-time variable-rate selective excitation (MinVER) to a presaturation pulse (PSP) with a high flip angle on 7 T time-of-flight magnetic resonance angiography (7T TOF-MRA), to attain a superior vessel-to-tissue contrast (VTCR), short acquisition time, and minor off-resonance effect. An altered PSP modified by using the 90° flip angle (FA)-MinVER was implemented in the 7 T TOF-MRA, and its performance was evaluated with a signal profile and vessel-tissue contrast ratios and compared to the conventional PSP and 45 FA-TOF. The 90 FA-MinVER showed a similar signal profile to that of the conventional PSP and improved the vessel-tissue contrast ratios (0.313 ± 0.80) compared to all conventional types (45 FA-TOF: 0.088 ± 0.84, 90 FA-TOF: 0.203 ± 0.72). Moreover, this noteworthy approach achieved substantially reduced total acquisition time (5 min and 55 s) with a short repeat-to-time (28 ms), indicating that at the 7 T TOF-MRA, the 90 FA-MinVER could be applied by default to suppress the venous signals regardless of individual human status and the specific absorption ratio constraint and with rapid imaging. Ultimately, its application could also help to observe subtle microvascular changes in the early stages and serve as key biomarkers in various vascular diseases.

Construction of the Signal Profile for Use in Blade Tip-Timing Analysis

The paper illustrates a fundamentally different approach applied to Blade Tip-Timing analysis in the background of works performed through the long history of this method. New innovative approach is based on the precise separation of measured data that was published in previous works. In this respect, the construction of the signal profile is intended for fast and accurate definition of the regulation function served to expression of the complete speed fluctuation and its instabilities. Following, the presented signal profile is demonstrated on four variants of data processing in two significantly different operations, where it allows the application of a one-step approach. Finally, these results are also compared with a two-step method used in previous cases without the signal profile. The benefit of the suggested procedure of the signal profile calculation is evident in the possibility of processing more complex functions in deterministic methods without limiting the characteristic advantages of these methods.

Флуктуационный анализ динамики систем с меняющимися во времени характеристиками

Improvement of the method of fluctuation analysis is performed, which includes taking into account the statistics of local standard deviations of the signal profile from piecewise linear approximation of the trend. It is shown that the proposed approach makes it possible to reduce the sensitivity of the method to single artifacts and increase the stability of the algorithm for computing the scaling exponent, which contributes to the wider use of the modified fluctuation analysis for solving problems of diagnosing complex processes in the dynamics of systems with time-varying characteristics.

Trait differences among discrete morphs of a color polymorphic lizard, Podarcis erhardii

Color polymorphism defies evolutionary expectations as striking phenotypic variation is maintained within a single species. Color and other traits mediate social interactions, and stable polymorphism within a population is hypothesized to be related to correlational selection of other phenotypic traits among color morphs. Here, we report on a previously unknown throat color polymorphism in the Aegean Wall Lizard (Podarcis erhardii) and examine morph-correlated differences in traits important to social behavior and communication: maximum bite force capacity and chemical signal profile. We find that both sexes of P. erhardii have three color morphs: orange, yellow, and white. Moreover, orange males are significantly larger and tend to bite harder than yellow and white males. Although the established color polymorphism only partially matches the observed intraspecific variation in chemical signal signatures, the chemical profile of the secretions of orange males is significantly divergent from that of white males. Our findings suggest that morph colors are related to differences in traits that are crucial for social interactions and competitive ability, illustrating the need to look beyond color when studying polymorphism evolution.

Benchmarking Reverse-Complement Strategies for Deep Learning Models in Genomics

Predictive models that map double-stranded regulatory DNA to molecular signals of regulatory activity should, in principle, produce identical predictions regardless of whether the sequence of the forward strand or its reverse complement (RC) is supplied as input. Unfortunately, standard convolutional neural network architectures can produce highly divergent predictions across strands, even when the training set is augmented with RC sequences. Two strategies have emerged in the literature to enforce this symmetry: conjoined a.k.a. “siamese” architectures where the model is run in parallel on both strands & predictions are combined, and RC parameter sharing or RCPS where weight sharing ensures that the response of the model is equivariant across strands. However, systematic benchmarks are lacking, and neither architecture has been adapted to base-resolution signal profile prediction tasks. In this work, we extend conjoined and RCPS models to signal profile prediction, and introduce a strong baseline: a standard model (trained on RC augmented data) that is converted to a conjoined model only after it has been trained, which we call a “post-hoc” conjoined model. We then conduct benchmarks on both binary and signal profile prediction. We find post-hoc conjoined models consistently perform as well as or better than models that were conjoined during training, and present a mathematical intuition for why. We also find that - despite its theoretical appeal - RCPS performs surprisingly poorly on certain tasks, in particular, signal profile prediction. In fact, RCPS can sometimes do worse than even standard models trained with RC data augmentation. We prove that the RCPS models can represent the solution learned by the conjoined models, implying that the poor performance of RCPS may be due to optimization difficulties. We therefore suggest that users interested in RC symmetry should default to post-hoc conjoined models as a reliable baseline before exploring RCPS. Code: https://github.com/hannahgz/BenchmarkRCStrategies

Energy Flexibility Assessment of a Zone with Radiant Floor Heating System by Means of Experimental Measurements

This article investigates the potential energy flexibility of a thermal zone that contains a hydronic radiant floor heating system embedded in a concrete slab. The energy flexibility of the zone is quantified from experimental measurements for a specific zone air set point change. The experiment was carried out in an experimental perimeter zone test cell (PZTC) designed to simulate the conditions of an office space near a window which has a radiant floor heating system. The PZTC is located inside a controlled environmental chamber (EC). The EC provides the desired exterior conditions. The temperature inside the PZTC is controlled with a thermostat that adjusts the heating power delivered from the hydronic pipes to the slab. It was observed that modulating the zone air temperature setpoint results in significant changes in the heating load, and thus providing a certain amount of energy flexibility. Application of the quantified energy flexibility along with applicable strategies in response to a specific price signal profile are discussed.

Laser-induced breakdown spectroscopy (LIBS) spectra interpretation and characterization using parallel factor analysis (PARAFAC): a new procedure for data and spectral interference processing fostering the waste electrical and electronic equipment (WEEE) recycling process

For the first time, PARAFAC was used to interpret and characterize LIBS spectra, providing the pure spectra, the signal profile and relative concentration of base and noble elements present on a printed circuit board from the hard disk.