Experimental Study of the Effect of the Expansion Segment Geometry on the Atomization of a Plain-Jet Airblast Atomizer

In this paper, the idea of adding an expansion segment over traditional airblast atomizer is proposed to improve the spray performance. According to the systematic experiments, the Sauter mean diameter, the droplet size distribution, and the droplet axial mean velocity were obtained to evaluate the spray performance. The correlations between spray performance and four geometrical parameters of the expansion segment which include the length, the angle, the throat area, and position of liquid jet are considered. The atomizer operates at atmospheric pressure and temperature, and the air liquid ratio range is from 0.48 to 2.85. The data of the results were measured by Phase Doppler Particle Analyzer. The results show that more uniform droplet size distribution can be achieved with the addition of expansion segment, and the droplet size distribution factor q of the case adding the expansion segment is 52.8% bigger than that of the case with no expansion segment. q increases as the length and angle of expansion segment increase. The Sauter mean diameter can be reduced by either reducing the length or angle of expansion segment. As for droplet velocity, it is determined that the droplet velocity increases along the radial direction, which is noteworthy because opposite trend is reported for traditional plain-jet atomizers. With an increase of the length, angle, and throat area of the expansion segment, the droplet axial velocity decays.

Trichinella spiralis in a cougar (Puma concolor) hunted by poachers in Chile

Trichinellosis is a zoonosis caused by nematodes of the Trichinella genus, of which 10 species have been described. Species identification when larvae is found is only possible using molecular tools. Meat from pigs and game animals not subjected to veterinary inspection are the main sources of human infections. The hunting of native carnivores is prohibited in Chile due to conservation issues and the fact that those animals favor pest control. The illegal hunting of a cougar (Puma concolor) occurred in September 2020. Herein, the molecular identification of Trichinella larvae, by analyzing nuclear (expansion segment V) and mitochondrial (cytochrome C oxidase subunit I) sequences are described. Both the amplification of the expansion segment V region and the phylogenetic analysis of a segment of a fragment of the cytochrome c-oxidase subunit I sequence confirmed that the larvae belonged to T. spiralis. The case described herein represents the first evidence of illegal hunting of a protected mammal infected with Trichinella in Chile, highlighting the ‘One Health’ perspective to face this disease in the rural-sylvatic interphase.

rRNA expansion segment 27Lb modulates the factor recruitment capacity of the yeast ribosome and shapes the proteome

Fine-tuned regulation of protein biosynthesis is crucial for cellular fitness and became even more vital when cellular and organismal complexity increased during the course of evolution. In order to cope with this augmented demand for translation control, eukaryal ribosomes have gained extensions both at the ribosomal protein and rRNA levels. Here we analyze the functional role of ES27L, an rRNA expansion segment in the large ribosomal subunit of Saccharomyces cerevisiae. Deletion of the b-arm of this expansion segment, called ES27Lb, did not hamper growth during optimal conditions, thus demonstrating that this 25S rRNA segment is not inherently crucial for ribosome functioning. However, reductive stress results in retarded growth and rendered unique protein sets prone to aggregation. Lack of ES27Lb negatively affects ribosome-association of known co-translational N-terminal processing enzymes which in turn contributes to the observed protein aggregation. Likely as a compensatory response to these challenges, the truncated ribosomes showed re-adjusted translation of specific sets of mRNAs and thus fine-tune the translatome in order to re-establish proteostasis. Our study gives comprehensive insight into how a highly conserved eukaryal rRNA expansion segment defines ribosomal integrity, co-translational protein maturation events and consequently cellular fitness.

Morphological and molecular characterisation of Chitwoodius coffeae sp. n. (Dorylaimida: Tylencholaimidae) from Vietnam, with a revised taxonomy of the genus

Summary Chitwoodius coffeae sp. n. is described, including SEM observations and molecular (D2-D3 expansion segment of the rDNA 28S) analysis, from a coffee plantation in the Central Highlands of Vietnam. The new species is characterised by its 1.69-2.01 mm long body in females and 1.29-1.51 mm in males, lip region offset by deep constriction and 15-17 μm broad, odontostyle 27-30 μm long, neck 340-473 μm long, pharyngeal expansion occupying 52-54% of total neck length, uterus a simple tube-like structure 68-106 μm long, vulva longitudinal (V = 54-59), tail short and rounded conoid (20-28 μm, c = 54-88, c′ = 0.6-0.8) with a nearly terminal projection of inner cuticle layer, spicules 60-64 μm long, and 7-10 spaced ventromedian supplements without hiatus. SEM pictures, available for the first time for a representative of the genus, show a hexagonal (nearly hexastellate) oral field divided into six sectors by the existence of six deep incisures. Molecular analyses, also presented for the first time for a representative of the genus, results in a narrow evolutionary relationship among Chitwoodius and Tylencholaimus, and supports the monophyly of the Tylencholaimidae. This is the first record of Chitwoodius in Asian Far East territories. Chitwoodius ahmadi sp. n. is proposed for a misattributed population of C. seshadrii.