A Chromosomal-Level Genome of Dermatophagoides farinae, a Common Allergenic Mite Species.

Background: Genome data have been used to find novel allergen from house dust mites. Here, we aim to construct a chromosome-level genome assembly of Dermatophagoides farinae, a common allergenic mite species. Methods: We achieved a chromosome-level assembly of D. farinae's genome by integrating PacBio single-molecule real-time sequencing, Illumina paired-end sequencing, and Hi-C technology, followed by annotating allergens and mapping them to specific chromosomes. Results: A 62.43 Mb genome was assembled with a 0.52% heterozygosity rate and a 36.11 Merqury-estimated quality value. The assembled genome represents 92.1% completeness benchmarking universal single-copy orthologs with a scaffold N50 value of 7.11 Mb. Hi-C scaffolding of the genome resulted in construction of 10 pseudochromosomes. The genome comprises 13.01% (7.66 Mb) repetitive sequences and predicts 10,709 protein-coding genes, 96.57% of which are functionally annotated. Moreover, we identified and located 36 allergen groups on specific chromosomes, including allergens Der f 1, Der f 2, Der f 23, Der f 4, Der f 5, Der f 7, and Der f 21 located on chromosomes 2, 1, 7, 3, 4, 6, and 4, respectively. Conclusion: This comprehensive genomic data provides valuable insights into mite biology and evolutionary adaptations, potentially advancing D. farinae allergy research and treatment strategies.

Tissue accumulation of microplastics and potential health risks in human.

Microplastics have become ubiquitous throughout the environment. Humans constantly ingest and inhale microplastics, increasing concerns about the health risks of microplastic exposure. However, limited data impedes a full understanding of the internal exposure to microplastics. Herein, to evaluate microplastic exposure via the respiratory and digestive systems, we used laser direct infrared spectroscopy to identify microplastics >20 µm in size in different human tissues. Consequently, 20-100 µm microplastics were concentrated in all tissues, with polyvinyl chloride (PVC) being the dominant polymer. The highest abundance of microplastics was detected in lung tissue with an average of 14.19 ± 14.57 particles/g, followed by that in the small intestine, large intestine, and tonsil (9.45 ± 13.13, 7.91 ± 7.00, and 6.03 ± 7.37 particles/g, respectively). The abundance of microplastics was also significantly greater in females than in males (p < 0.05). Despite significant diversity, our estimation showed that the lungs accumulated the highest amounts of microplastic. Moreover, PVC particles may cause potential health risks because of their high polymer hazard index and maximal risk level. This study provides evidence regarding the occurrence of microplastics in humans and empirical data to support assessments of the health risks posed by microplastics.

Upconversion Luminescence Properties of Phase and Size Controlled NaLnF4:Yb3+, Er3+(Ln = Y, Gd) Nanoparticles.

The upconversion luminescent nanoparticles of NaLnF4 (Ln = Y, Gd):Yb3+, Er3+ were prepared through a facile modified solvothermal method, in which the phase (cubic or hexagonal) and size of the NaLnF4 nanoparticles can be well controlled by adjusting Gd3+ content. The Gd3+ content dependent phase transformation and size change were systematically studied by the XRD and TEM measurements. The spectral measurement revealed that both the emission intensity and the intensity ratio of red (4F9/2 -,4 115/2) to green (2H11/2, 4S3/2 --> 4I15/2) are tunable, and a significant increase of the visible upconversion emission intensity can be realized by optimizing Gd3+ content at x = 0.25 under 980 nm excitation. Furthermore, the excitation power dependent red and green emission intensities of Er3+ were measured for various NaLnF4 (Ln = Y, Gd):Yb3+, Er3+ nanoparticles with different Gd3+ content to investigate the influence of the phase and particle size on the upconversion luminescence properties. This research provided a new method to synthesize the upconversion nanoparticles with tunable luminescence properties by adjusting Gd3+ content.

pH value manipulated phase transition, microstructure evolution and tunable upconversion luminescence in Yb(3+)-Er(3+) codoped LiYF4/YF3 nanoparticles.

The pH value plays an important role in controlling the crystallization process and microstructure of the final products in the synthesis of nanocrystals with a solvothermal method. This work reported the effect of the mother solution pH value on the precipitation of LiYF4 and YF3 nanoparticles, as well as the microstructure evaluation of YF3 from a bowknot-like to spindle-like shape. Spectroscopy study suggests that there is strong correlation between the upconversion emission properties of the Yb(3+)-Er(3+) couple and the phase and the microstructure of the host. The strongest emissions and lowest red-to-green ratio are observed in the bowknot-like YF3 nanocrystals with the largest open ends. Further spectral investigation indicates that the phase and microstructure dependent upconversion properties are associated with the upconversion efficiency. The present study is of great importance in the design and synthesis of rare earth ion doped nanocrystals with tunable upconversion properties.

Broadband downshifting luminescence in Cr³âºâ‚‹Yb³âº codoped garnet for efficient photovoltaic generation.

The Cr³âºâ‚‹Yb³âº codoped YAG crystals were synthesized by the solid state reaction method, in which the intense near-infrared emission around 1000 nm originated from Yb³âº ²F5/2 →²F7/2 transition was obtained due to the efficient energy transfer from Cr³âº to Yb³âº. The stable and transient spectral measurements revealed that the phonon assistant energy transfer process is responsible for the energy transfer from Cr³âº to Yb³âº upon both the excitations of Cr³âº: 4T1 and 4T2> energy levels. Due to the effective absorption of Cr³âº in the visible region in YAG and the efficient energy transfer to Yb³âº, this material can be developed as spectral convertors to improve silicon solar cell photovoltaic conversion efficiency.