bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extraction and separation of astaxanthin with the help of pre-treatment of Haematococcus pluvialis microalgae biomass using aqueous two-phase systems based on deep eutectic solvents
Authors: Nemani Neda , Dehnavi Seyed Mohsen , Pazuki Gholamreza 
Published: March 2024

AbstractThe microalgae Haematococcus pluvialis are the main source of the natural antioxidant astaxanthin. However, the effective extraction of astaxanthin from these microalgae remains a significant challenge due to the rigid, non-hydrolyzable cell walls. Energy savings and high-efficiency cell disruption are essential steps in the recovery of the antioxidant astaxanthin from the cysts of H. pluvialis. In the present study, H. pluvialis microalgae were first cultured in Bold's Basal medium under certain conditions to reach the maximum biomass concentration, and then light shock was applied for astaxanthin accumulation. The cells were initially green and oval, with two flagella. As the induction time increases, the motile cells lose their flagellum and become red cysts with thick cell walls. Pre-treatment of aqueous two-phase systems based on deep eutectic solvents was used to decompose the cell wall. These systems included dipotassium hydrogen phosphate salt, water, and two types of deep eutectic solvents (choline chloride–urea and choline chloride–glucose). The results of pre-treatment of Haematococcus cells by the studied systems showed that intact, healthy cysts were significantly ruptured, disrupted, and facilitated the release of cytoplasmic components, thus facilitating the subsequent separation of astaxanthin by liquid–liquid extraction. The system containing the deep eutectic solvent of choline chloride–urea was the most effective system for cell wall degradation, which resulted in the highest ability to extract astaxanthin. More than 99% of astaxanthin was extracted from Haematococcus under mild conditions (35% deep eutectic solvent, 30% dipotassium hydrogen phosphate at 50 °C, pH = 7.5, followed by liquid–liquid extraction at 25 °C). The present study shows that the pre-treatment of two-phase systems based on deep eutectic solvent and, thus, liquid–liquid extraction is an efficient and environmentally friendly process to improve astaxanthin from the microalgae H. pluvialis.
Structural basis for the recognition of human hemoglobin by the heme-acquisition protein Shr from Streptococcus pyogenes
Authors: Senoo Akinobu , Hoshino Masato , Shiomi Toshiki , Nakakido Makoto , Nagatoishi Satoru , Kuroda Daisuke , Nakagawa Ichiro , Tame Jeremy R. H. , Caaveiro Jose M. M. , Tsumoto Kouhei 
Published: March 2024

AbstractIn Gram-positive bacteria, sophisticated machineries to acquire the heme group of hemoglobin (Hb) have evolved to extract the precious iron atom contained in it. In the human pathogen Streptococcus pyogenes, the Shr protein is a key component of this machinery. Herein we present the crystal structure of hemoglobin-interacting domain 2 (HID2) of Shr bound to Hb. HID2 interacts with both, the protein and heme portions of Hb, explaining the specificity of HID2 for the heme-bound form of Hb, but not its heme-depleted form. Further mutational analysis shows little tolerance of HID2 to interfacial mutations, suggesting that its interaction surface with Hb could be a suitable candidate to develop efficient inhibitors abrogating the binding of Shr to Hb.
The second-order coherence analysis of number state propagation through dispersive non-Hermitian multilayered structures
Authors: Pilehvar Elnaz , Amooghorban Ehsan , Moravvej-Farshi Mohammad Kazem 
Published: March 2024

AbstractTo examine the second-order coherence of light propagation of quantum states in arbitrary directions through dispersive non-Hermitian optical media, we considered two sets of non-Hermitian periodic structures that consist of gain/loss unit cells. We show that each batch can satisfy the parity-time symmetry conditions at a distinct frequency. We then varied the gain/loss strength in the stable electromagnetic regime to evaluate the transmittance of N-photon number states through each structure. The results show both sets preserve their antibunching characteristics under specific incident light conditions. Furthermore, s(p)-polarized light exhibits higher (lower) second-order coherence at larger incident angles. In addition, the antibunching features of the transmitted states degrade with an increase in the number of unit cells in multilayered structures for both polarizations.
The seed dispersal syndrome hypothesis in ungulate-dominated landscapes
Authors: Fedriani Jose M. , Garrote Pedro J. , Burgos Tamara , Escribano-Ávila Gema , Morera Brayan , Virgós Emilio 
Published: March 2024

AbstractThe Seed Dispersal Syndrome Hypothesis (SDSH) posits that fruit traits predict the main dispersers interacting with plant species. Mammalian dispersers, relying heavily on olfactory cues, are expected to select dull-colored, scented, and larger fruits compared to birds. However, challenges like overabundant seed predators and context-dependency of frugivore-plant interactions complicate SDSH expectations. We studied the Iberian pear, Pyrus bourgaeana, an expected mammal-dispersed tree based on its fruit traits. Extensive camera-trapping data (over 35,000 records) from several tree populations and years revealed visits from seven frugivore groups, with ungulate fruit predators (59–97%) and carnivore seed dispersers (1–20%) most frequent, while birds, lagomorphs, and rodents were infrequent (0–10%). Red deer and wild boar were also the main fruit removers in all sites and years but acted as fruit and seed predators, and thus likely exert conflicting selection pressures to those exerted by seed dispersers. Although, as predicted by the SDSH, most Iberian pear fruits were consumed by large and medium-sized mammals, the traits of Iberian pear fruits likely reflect selection pressures from dispersal vectors in past times. Our results do not challenge the SDHS but do reveal the importance of considering frugivore functional roles for its adequate evaluation.
Utilizing Ni(II) complex for metal drug-gel particles in cervical cancer treatment and designing novel drugs through machine learning methods
Authors: Jiang Meiping , Wu Ruiping , Liu Dongqin , Wang Xiaoli 
Published: March 2024

AbstractIn the present study, a novel coordination polymer (CP) based on Ni(II), namely, [Ni(L)(D-CAM)(H2O)]n (1) (H2D-CAM = (1R,3S)-1,2,2-trimethylcyclopentane-1,3-dicarboxylic acid and L = 3,6-bis(benzimidazol-1-yl)pyridazine), has been produced successfully through applying a mixed ligand synthesis method via reacting Ni(NO3)2·6H2O with 3,6-bis(benzimidazol-1-yl)pyridazine ligand in the presence of a carboxylic acid co-ligand. Hyaluronic acid (HA) and carboxymethyl chitosan (CMCS) are representatives of natural polysaccharides and have good biocompatibility. Based on the chemical synthesis method, HA/CMCS hydrogel was successfully prepared. SEM showed that the lyophilized gel presented a typical macroporous structure with three-dimensional connected pores, which had unique advantages as a drug carrier. Using paclitaxel as a drug model, we further synthesized a novel paclitaxel-loaded metal gel and evaluated its therapeutic effect on cervical cancer. Finally, novel drugs from the reinforcement learning simulation are suggested to have better biological activity against ovarian cancer due to low affinity energy and stronger interaction strength towards the protein receptor.
Uncovering the microbiome landscape in sashimi delicacies
Authors: Ho Cheng‑Wei , Chen Pei‑Ying , Liao Yi-Ting , Cheng Yen-Fu , Tsou Han-Hsing , Liu Tsung‑Yun , Liang Kung-Hao 
Published: March 2024

AbstractIt is widely believed that a significant portion of the gut microbiota, which play crucial roles in overall health and disease, originates from the food we consume. Sashimi is a type of popular raw seafood cuisine. Its microbiome, however, remained to be thoroughly explored. The objective of this study is to explore the microbiome composition in sashimi at the time when it is served and ready to be eaten. Specifically, our tasks include investigating the diversity and characteristics of microbial profiles in sashimi with respect to the fish types. We utilized the Sanger-sequencing based DNA barcoding technology for fish species authentication and next-generation sequencing for sashimi microbiome profiling. We investigated the microbiome profiles of amberjack, cobia, salmon, tuna and tilapia sashimi, which were all identified using the MT-CO1 DNA sequences regardless of their menu offering names. Chao1 and Shannon indexes, as well as Bray–Curtis dissimilarity index were used to evaluate the alpha and beta diversities of sashimi microbiome. We successfully validated our previous observation that tilapia sashimi has a significantly higher proportions of Pseudomonas compared to other fish sashimi, using independent samples (P = 0.0010). Salmon sashimi exhibited a notably higher Chao1 index in its microbiome in contrast to other fish species (P = 0.0031), indicating a richer and more diverse microbial ecosystem. Non-Metric Multidimensional Scaling (NMDS) based on Bray–Curtis dissimilarity index revealed distinct clusters of microbiome profiles with respect to fish types. Microbiome similarity was notably observed between amberjack and tuna, as well as cobia and salmon. The relationship of microbiome similarity can be depicted as a tree which resembles partly the phylogenetic tree of host species, emphasizing the close relationship between host evolution and microbial composition. Moreover, salmon exhibited a pronounced relative abundance of the Photobacterium genus, significantly surpassing tuna (P = 0.0079), observed consistently across various restaurant sources. In conclusion, microbiome composition of Pseudomonas is significantly higher in tilapia sashimi than in other fish sashimi. Salmon sashimi has the highest diversity of microbiome among all fish sashimi that we analyzed. The level of Photobacterium is significantly higher in salmon than in tuna across all the restaurants we surveyed. These findings provide critical insights into the intricate relationship between the host evolution and the microbial composition. These discoveries deepen our understanding of sashimi microbiota, facilitating our decision in selecting raw seafood.
Explanation of the influence of geomorphometric variables on the landform classification based on selected areas in Poland
Authors: Dyba Krzysztof 
Published: March 2024

AbstractIn recent years, automatic image classification methods have significantly progressed, notably black box algorithms such as machine learning and deep learning. Unfortunately, such efforts only focused on improving performance, rather than attempting to explain and interpret how classification models actually operate. This article compares three state-of-the-art algorithms incorporating random forests, gradient boosting and convolutional neural networks for geomorphological mapping. It also attempts to explain how the most effective classifier makes decisions by evaluating which of the geomorphometric variables are most important for automatic mapping and how they affect the classification results using one of the explainable artificial intelligence techniques, namely accumulated local effects (ALE). This method allows us to understand the relationship between predictors and the model’s outcome. For these purposes, eight sheets of the digital geomorphological map of Poland on the scale of 1:100,000 were used as the reference material. The classification results were validated using the holdout method and cross-validation for individual sheets representing different morphogenetic zones. The terrain elevation entropy, absolute elevation, aggregated median elevation and standard deviation of elevation had the greatest impact on the classification results among the 15 geomorphometric variables considered. The ALE analysis was conducted for the XGBoost classifier, which achieved the highest accuracy of 92.8%, ahead of Random Forests at 84% and LightGBM at 73.7% and U-Net at 59.8%. We conclude that automatic classification can support geomorphological mapping only if the geomorphological characteristics in the predicted area are similar to those in the training dataset. The ALE plots allow us to analyze the relationship between geomorphometric variables and landform membership, which helps clarify their role in the classification process.
Metal leakage from orthodontic appliances chemically alters enamel surface during experimental in vitro simulated treatment
Authors: Topolska Justyna M. , Jagielska Agata , Motyl Sylwia , Kozub-Budzyń Gabriela A. , Kępa Luiza , Wagner Barbara , Wątor Katarzyna 
Published: March 2024

AbstractHuman enamel is composed mainly of apatite. This mineral of sorption properties is susceptible to chemical changes, which in turn affect its resistance to dissolution. This study aimed to investigate whether metal leakage from orthodontic appliances chemically alters the enamel surface during an in vitro simulated orthodontic treatment. Totally 107 human enamel samples were subjected to the simulation involving metal appliances and cyclic pH fluctuations over a period of 12 months in four complimentary experiments. The average concentrations and distribution of Fe, Cr, Ni, Ti and Cu within the enamel before and after the experiments were examined using ICP‒MS and LA‒ICP‒MS techniques. The samples exposed to the interaction with metal appliances exhibited a significant increase in average Fe, Cr and Ni (Kruskal–Wallis, p < 0.002) content in comparison to the control group. The outer layer, narrow fissures and points of contact with the metal components showed increased concentrations of Fe, Ti, Ni and Cr after simulated treatment, conversely to the enamel sealed with an adhesive system. It has been concluded that metal leakage from orthodontic appliances chemically alters enamel surface and microlesions during experimental in vitro simulated treatment.
Research on WSN reliable ranging and positioning algorithm for forest environment
Authors: Wu Peng , Yu Le , Yi Xiaomei , Xu Liang , Liu LiJuan , Yi YuTong , Jiang Tengteng , Tao Chunling 
Published: March 2024

AbstractWireless sensor network (WSN) location is a significant research area. In complex environments like forests, inaccurate signal intensity ranging is a major challenge. To address this issue, this paper presents a reliable WSN distance measurement-positioning algorithm for forest environments. The algorithm divides the positioning area into several sub-regions based on the discrete coefficient of the collected signal strength. Then, using the fitting method based on the signal intensity value of each sub-region, the algorithm derives the reference points of the logarithmic distance path loss model and path loss index. Finally, the algorithm locates target nodes using anchor nodes in different regions. Additionally, to enhance the positioning accuracy, weight values are assigned to the positioning result based on the discrete coefficient of the signal intensity in each sub-region. Experimental results demonstrate that the proposed WSN algorithm has high precision in forest environments.
Structural insights into the binding mechanism of Clr4 methyltransferase to H3K9 methylated nucleosome
Authors: Saab Christopher , Stephan Joseph , Akoury Elias 
Published: March 2024

AbstractThe establishment and maintenance of heterochromatin, a specific chromatin structure essential for genomic stability and regulation, rely on intricate interactions between chromatin-modifying enzymes and nucleosomal histone proteins. However, the precise trigger for these modifications remains unclear, thus highlighting the need for a deeper understanding of how methyltransferases facilitate histone methylation among others. Here, we investigate the molecular mechanisms underlying heterochromatin assembly by studying the interaction between the H3K9 methyltransferase Clr4 and H3K9-methylated nucleosomes. Using a combination of liquid-state nuclear magnetic resonance spectroscopy and cryo-electron microscopy, we elucidate the structural basis of Clr4 binding to H3K9-methylated nucleosomes. Our results reveal that Clr4 engages with nucleosomes through its chromodomain and disordered regions to promote de novo methylation. This study provides crucial insights into the molecular mechanisms governing heterochromatin formation by highlighting the significance of chromatin-modifying enzymes in genome regulation and disease pathology.
Metal–organic framework-based adsorbents for blood purification: progress, challenges, and prospects
Authors: Wang Jiemin , Cheng Chong , Sun Shudong , Zhao Weifeng , Zhao Changsheng 
Published: March 2024

This review for the first time summarizes the structure–function relationship between MOFs and toxin adsorption, as well as the biocompatibility and practicality for HD, HP, and ECMO. It is anticipated that this review will expand the interest of researchers for more impact in this area.
Feasibility study on retrieving exoplanetary cloud cover distributions using polarimetry
Authors: Winning S. , Lietzow-Sinjen M. , Wolf S. 
Published: March 2024

Context. As a new growing field, exocartography aims to map the surface features of exoplanets that are beyond the resolution of traditional observing techniques. While photometric approaches have been discussed extensively, polarimetry has received less attention despite its promising prospects.
Aims. We demonstrate that the limb polarization of an exoplanetary atmosphere offers valuable insights into its cloud cover distribution. Specifically, we determine an upper limit for the polarimetric precision, which is required to extract information about the latitudinal cloud cover of temperate Jovian planets for scenarios of observations with and without host stars.
Methods. To compute the scattered stellar radiation of an exoplanetary atmosphere and to study the polarization at various planetary phase angles, we used the three-dimensional Monte Carlo radiative transfer code POLARIS.
Results. When the planetary signal can be measured separately from the stellar radiation, information about the latitudinal cloud cover for polar cap models is accessible at polarimetric sensitivities of 0.1%. In contrast, a precision of about 10−3 ppm is required when the stellar flux is included to gain this information.
The dielectric properties of silicone-multiwall carbon nanotubes nanocomposite in the frequency range from 0.5 to 20 GHz
Authors: Altarawneh Moaz M. 
Published: March 2024

Integrating carbon nanotubes (CNTs) into a polymer matrix can significantly modify its physical properties, providing that the challenges associated with CNT dispersion are successfully resolved. In this work, we investigate the enhancement of the dielectric properties of silicone when multiwall carbon nanotubes (MWCNTs) are introduced to its polymer matrix as a filler in the frequency range from 0.5 to 20 GHz. An optimized procedure is used to prepare nanocomposites with MWCNTs concentrations by weight of 0%, 0.5%, 1.0%, 1.5%, and 2.0%. The investigated dielectric properties for the prepared nanocomposites are the real dielectric constant ɛ′, the imaginary dielectric constant ɛ″, the loss tangent tan δ, and the AC conductivity σAC. The dispersion of the MWCNTs in the silicone matrix is confirmed using the Fourier-transform infrared (FTIR) spectroscopy and the scanning electron microscope. This study shows that the dielectric properties of the nanocomposite are enhanced as the MWCNT’s concentration is increased over the entire frequency range. For example, the enhancement in ɛ′ value was from 3.2 up to 21.6 at 0.5 GHz and from 2.5 to 10.6 at 20 GHz as the concentration increased from 0% to 2.0%. For the ɛ″ value, the enhancement was from less than 0.1 to 8.6 at 0.5 GHz and to 2.0 at 20 GHz, respectively. Based on the obtained tanδ values, the nanocomposites with MWCNTs of 0.5% and 1.0% can be classified as low-loss dielectrics, while the other nanocomposites with MWCNTs of 1.5% and 2.0% are classified as lossy dielectrics.
Enhanced physical properties of stable lead-free oxide double perovskite Ba2TbBiO6 for photovoltaics: Effects of Sb doping
Authors: Saha Samiron Kumar , Khan Mithun , Hasan Zahid , Chandra Roy Dayal , Ali Md Lokman 
Published: March 2024

The effect of Sb-doping in the Bi-based double perovskite Ba2TbBi1-xSbxO6(x = 0.0, 0.5) on providing a structural and electronic framework for understanding numerous physical aspects at an atomistic level. We study in detail the undoped and Sb-doped Ba2TbBiO6 double perovskite’s structural, elastic, mechanical, electronic, and thermodynamic properties for both cubic and monoclinic phases. Doping alters the spatial group structure and lattice constant of Ba2TbBi1−xSbxO6, causing a change in the Brillouin zone, which alters the band structure and bandgap value. The elastic constants confirmed the ductility of the solids and ensured mechanical stability in both phases. This study reveals that both phases of Ba2TbBi1−xSbxO6 are more mechanically stable, ductile, and machinable than Ba2TbBiO6. The Sb-doped monoclinic phase had greater anisotropy than the cubic phase, despite the fact that both phases were anisotropic. Vickers hardness shows that the monoclinic Ba2TbBi1−xSbxO6(x = 0.0, 0.5) phase is harder than the cubic Ba2TbBi1−xSbxO6(x = 0.0, 0.5) phases. The cubic and monoclinic phases of Ba2TbBi0.5Sb0.5O6 have Debye temperatures of 248.48 and 240.75 K, respectively. After doping, the cubic phase’s melting temperature (1529.21 K) grows higher than that of the monoclinic phase (1386.87 K). Doping can make a material more stable by lowering its thermal expansion coefficient. Both doped phases can be used as thermal barrier coatings (TBCs).
Myrtaceae anther glands: morphology, anatomy and variation in glandular contents
Authors: Ladd P. G. 
Published: March 2024

Context Most tissues of Myrtaceae plants have oil glands. The anthers of many species have an oil-containing apical gland that is larger than those in other tissues of the plant. Aims Representative species in the family were examined for the diversity of gland form and their oil contents. Methods Representative anthers were sectioned for light microscopy and scanning electron microscopy study and anthers from selected species were analysed for oil content. Key results The most common gland form is globular and narrowly attached to the apex of the connective, but in members of certain tribes, the gland is completely enclosed in the connective. The greatest morphological diversity is in the Chamelaucieae. Anther glands vary from plesiomorphic globular forms to glands that are larger than the anther thecae and almost completely fill the connective. Conclusions There are three possible functions for the glands, including the following: (1) protecting the anthers from herbivores, (2) mixing with the pollen to aid adhesion to stylar hairs on many Chamelaucineae, and (3) rewarding pollinators that use the oil–pollen mixture as food. Implications It is generally considered that the oils in various tissues of the Myrtaceae deter herbivores. In Myrtaceae with abundant anthers, the glands could deter flower visitors from consuming the anthers. Gland oil of the Eucalyptus and Leptospermum species examined contained α pinene as did the leaves of all species examined. The gland oil composition in Chamelaucium uncinatum and Verticordia grandis that have pollen presenters was different from that in the leaves and also different from that in the anthers of the two Verticordia species where bees collect the pollen–oil mixture for food.