Preliminary studies of the tardigrada communities from a polymetallic nodule area of the deep South China Sea

Knowledge about marine tardigrades from the South China Sea is very scarce, with only four species from shallow waters recorded to date. The present study investigated the structure and diversity of tardigrade communities from the deep sea (1517-1725 m) at 8 stations in a polymetallic nodule area of the northern South China Sea. A total of 151 arthrotardigrades were collected belonging to 11 genera (Angursa, Batillipes, Coronarctus, Euclavarctus, Exoclavarctus, Halechiniscus, Moebjergarctus, Raiarctus, Rhomboarctus, Tanarctus and Tholoarctus), representing 17 species. Two Angursa species (Angursa sp. 4 and Angursa sp. 3) were the most abundant (25.2% and 14.6%, respectively), followed by Moebjergarctus sp. (13.9%). Specimens were mostly (90.7%) distributed in the upper layer of the sandy-mud sediment (0-1 cm). The SIMPROF test showed that the composition of tardigrade communities at all stations was not significantly different. At different stations, the number of species, Shannon-Wiener diversity index and Pielou’s evenness index ranged from 4 to 10, 1.94 to 2.87, and 0.75 to 1.00, respectively. The average taxonomic distinctness (D+) ranged from 72.50 to 90.00, and the variation in taxonomic distinctness (L+) ranged from 316.67 to 1181.25. This study provides some basic information about the biodiversity of the marine tardigrade community in the South China Sea.info:eu-repo/semantics/publishedVersio

Microscopic Kinetics Pathway of Salt Crystallization in Graphene Nanocapillaries.

The fundamental understanding of crystallization, in terms of microscopic kinetic and thermodynamic details, remains a key challenge in the physical sciences. Here, by using in situ graphene liquid cell transmission electron microscopy, we reveal the atomistic mechanism of NaCl crystallization from solutions confined within graphene cells. We find that rock salt NaCl forms with a peculiar hexagonal morphology. We also see the emergence of a transitory graphitelike phase, which may act as an intermediate in a two-step pathway. With the aid of density functional theory calculations, we propose that these observations result from a delicate balance between the substrate-solute interaction and thermodynamics under confinement. Our results highlight the impact of confinement on both the kinetics and thermodynamics of crystallization, offering new insights into heterogeneous crystallization theory and a potential avenue for materials design.Royal Commission for the Exhibition of 185

First record of a deep-sea tardigrade from the South China Sea, Halechiniscus janus sp. nov. (Arthrotardigrada: Halechiniscidae)

Bai, Lifen, Wang, Xiaogu, Gao, Xiaohui, Li, Yujie, Fontoura, Paulo (2022): First record of a deep-sea tardigrade from the South China Sea, Halechiniscus janus sp. nov. (Arthrotardigrada: Halechiniscidae). Zootaxa 5159 (3): 425-439, DOI: https://doi.org/10.11646/zootaxa.5159.3.

Moebjergarctus clarionclippertonensis, a new abyssal tardigrade (Arthrotardigrada, Halechiniscidae, Euclavarctinae) from the Clarion-Clipperton Fracture Zone, North-East Pacific

Bai, Lifen, Wang, Xiaogu, Zhou, Yadong, Lin, Shiquan, Meng, Fanxu, Fontoura, Paulo (2020): Moebjergarctus clarionclippertonensis, a new abyssal tardigrade (Arthrotardigrada, Halechiniscidae, Euclavarctinae) from the Clarion-Clipperton Fracture Zone, North-East Pacific. Zootaxa 4755 (3): 561-575, DOI: 10.11646/zootaxa.4755.3.

Moebjergarctus clarionclippertonensis Bai & Wang & Zhou & Lin & Meng & Fontoura 2020, sp. nov.

Moebjergarctus clarionclippertonensis sp. nov. (Figs 2–6, Table 2) Diagnosis. Moebjergarctus with eleven cephalic sense organs present (paired internal cirri, paired external cirri, unpaired median cirrus, paired primary clavae, paired secondary clavae and paired cirri A). Primary clavae clubshaped, bent anteriorly. Secondary clavae spherical.Annulated spines on the first three pairs of legs I, II, III, divided on legs I, undivided on legs II and III. Small claviform papillae on legs IV. Long cirri E, each with cirrophore, annulated scapus and flagellum. Wrinkled digits terminated in simple crescent-shaped claws retractable into membranous sheaths. Internal digits longer than external digits. Cephalic cirri separated into three parts: short cirrophore, long annulated scapus and short flagellum. Scapi of cephalic cirri annulated only in the proximal portion followed by a smooth distal portion. Caudodorsally, a bulge covered by a crescent-shaped cuticular thickening is present. Female gonopore rosette-shaped. Male gonopore is circular with two slightly protruded internal folds, forming a longitudinal fissure. Adjacent to the male gonopore a posterior ovate thin and smooth cuticular platelet is present. Elongated seminal receptacles and long S-shaped seminal receptacle ducts opening laterally to the female gonopore. Type locality. The Clarion-Clipperton Fracture Zone (9.60°N– 10.85°N, 154.16°W– 156.48°W), 5135–5281 m depth (North-East Pacific). Material examined. Holotype, adult female (slide B 6418500008) collected at station KW1-S38, mounted in glycerine. Seventeen paratypes: One paratype of unknown gender (slide B 6418500004) collected at station KW1- S02; seven paratypes collected at station KW1-S05— three females (slides B 6418500019, SEM stubs B 6418500013 and B 6418500014), two males (slide B 6418500018 and SEM stub B 6418500016), a second instar juvenile (slide B 6418500017) and one specimen of unknown gender (slide B 6418500015); four paratypes collected at station KW1-S07— one female (SEM stub B 6418500012), one male (slide B 6418500010) and two specimens of unknown gender (SEM stub B 6418500009 and B 6418500011); three paratypes collected at station KW1-S38—one female (SEM stub B6418500005), one male (slide B6418500007) and a first instar juvenile (two-clawed larva, slide B6418500006); one paratype of unknown gender collected at KW1-S03 (slide B 6418500003); one paratype, male (SEM stub B6418500020) collected at station A5-S06. Unfortunately, slide B6418500004 and SEM stub B6418500011 were lost during the study. All specimens were collected from sediments outside of manganese nodules. Type repository. The type material (slides and SEM stubs) is deposited in Lin’an Base Sample Bank of Key Laboratory of Marine Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources of the People’s Republic of China. Etymology. The name clarionclippertonensis refers to the locus typicus of the new species, the Clarion-Clipperton Fracture Zone. Description of the holotype. Adult female (Figs 2A, B) with an unarmoured ovoid body (288 µm long, 105 µm wide between legs III and IV). Cuticle finely punctated, exhibiting a caudodorsal bulge, protruding 7.6 µm above the body surface, and covered by a crescent-shaped cuticular thickening (Figs 3 A–D). Conical head (30.9 µm wide between the bases of the primary clavae) with a long apical retractable buccal cone, bearing eleven cephalic sensory organs (Figs 2B, 4A, B). Primary clavae (Figs 4A, B) club-shaped, bent anteriorly (15.7 µm long and 4.9 µm wide). Secondary clavae spherical (diameter 5.9 µm) (Figs 4B, E). Tertiary clavae absent. All cephalic cirri (Figs 4 B–F) with a short elongated cirrophore with annular enlarged distal margin, long scapus with the proximal portion annulated followed by a smooth distal portion terminated by a blunt tip and a very short tubular flagellum with an opened tip (the opened tip is visible only in paratypes observed under SEM, Fig. 4E). Paired cirri A (Fig. 4C) 14.8 µm long (cirrophore 1.9 µm long, scapus 11.7 µm long comprising of the basal annulated portion (6.4 µm), apical smooth portion (5.3 µm), flagellum 1.2 µm long). Cirri A and primary clavae are clearly separated (Figs 2A, B, 4A, B). Paired external cirri, inserted ventrally to secondary clavae (Figs 4B, E), 12.3 µm long (cirrophore 2.9 µm long, scapus 7.6 µm long comprising of the basal annulated portion (4.8 µm), apical smooth portion (2.8 µm), flagellum 1.8 µm long). Paired dorsal internal cirri (Fig. 4F) 9.1 µm long (cirrophore 2.9 µm long, scapus 4.8 µm long comprising of the basal annulated portion (2.0 µm), apical smooth portion (2.8 µm), flagellum 1.4 µm long). The unpaired median cirrus (Fig. 4D) 12.6 µm long (cirrophore 1.4 µm long, scapus 10.2 µm long comprising of the basal annulated portion (5.8 µm), apical smooth portion (4.4 µm), flagellum 1.0 µm long). Cirri E, each 62.6 µm long, are inserted on a short cirrophore and have long annulated scapus and long and thin flagellum (Figs 2 A–C, 3A, D). Legs I–III with spine-shaped sensory organs. Leg I sensory organs (8.7 µm long) have an inconspicuous cirrophore and are divided into a scapus, with the proximal annulated portion and the distal smooth portion, and a short tubular tip (Fig. 5A). On legs II and III sensory organs are similar in size and shape (6.8 and 6.9 µm long, respectively). They are undivided, with annulated proximal portions and smooth distal portions (Figs 5B, C). Sensory organ on legs IV is a papilla (8.2 µm long) with a very short protruded tip (Fig. 5D). Each telescopic leg with coxa, femur, tibia and tarsus. Coxa and femur clearly punctated, tibia finely punctated and tarsus smooth. Each foot has four helically wrinkled digits. Digits are terminated by simple crescent-shaped claws (Figs 5E, F) retractable into membranous sheath. Digits are longer on legs IV than on legs I–III and, on each leg, internal digits are longer than external ones (30.9 and 24.0 µm on legs IV, 19.1 and 16.5 µm on legs I–III for internal and external digits, respectively). Long and thin buccal tube (76.6 µm long and ca. 2 µm wide) ending with an almost spherical pharyngeal bulb (15.8 × 15.4 µm), containing three thin, rod-shaped placoids (about 7.5 µm). Stylets 74.3 µm long, with stylet sheaths (43.2 µm long). Stylet supports were not observed. Female gonopore consists of a rosette (about 10.3 µm in diameter) with six cells (Figs 6A, C, E). Seminal receptacles are elongated vesicles, continued by long S-shaped seminal receptacle ducts (Figs 6A, E). Each seminal receptacle duct leaves the seminal receptacle posteriorly, then loops frontwards and after a second loop it turns backwards again to open laterally into the gonopore, after a small internal triangular receptacle duct pouch (Figs 6A, E). The anal opening is 12 µm distant from the gonopore. Remarks. Males seem to have slightly longer cirri E than females, but this character needs to be confirmed with the examination of a larger number of specimens; regarding other morphological and morphometric characters, males are similar to females (Table 2). The male gonopore is peculiarly formed, circular, with two slightly protruded internal folds, forming a longitudinal fissure. Adjacent to the gonopore a posterior oval thin and smooth cuticular platelet (9.3 µm wide in male B6418500018) is present. This platelet, sloping towards the gonopore, forming a funnel-like depression (Figs 6B, D, F). ......continued on the next page The two-clawed first instar juvenile (= larva, B6418500006) was the smallest specimen examined with a body length of 101 µm (measurements in Table 2). With the exception of missing external claws, anus and gonopore, all other characteristics as in the adults. Specimen B6418500017, the second instar four-clawed juvenile (gonopore was not observed), although smaller, is also similar to the adults (Table 2). The largest specimen examined was a 352 µm long female (B6418500014). The number of annuli on scapi of cephalic cirri, described in Moebjergarctus manganis as an important trait (Bussau 1992), is difficult to evaluate in the specimens examined for the purpose of this study because some annuli exhibit an asymmetric subdivision, a single on one side and a double on the other side (see Fig. 4F). In the studied specimens and mostly based on SEM images, the number of annuli on scapi of the cephalic cirri was evaluated as follows: median cirrus: 4–6, internal cirri: 3–5, external cirri: 4–6, cirri A: 7–10. Concerning leg sensory organs, it was not possible to estimate the number of annuli due to the abovementioned reason, and also to the accumulation of debris at the bases of these structures, what prevented a confident observation in SEM (see Figs 5B, C).Published as part of Bai, Lifen, Wang, Xiaogu, Zhou, Yadong, Lin, Shiquan, Meng, Fanxu & Fontoura, Paulo, 2020, Moebjergarctus clarionclippertonensis, a new abyssal tardigrade (Arthrotardigrada, Halechiniscidae, Euclavarctinae) from the Clarion-Clipperton Fracture Zone, North-East Pacific, pp. 561-575 in Zootaxa 4755 (3) on pages 564-572, DOI: 10.11646/zootaxa.4755.3.8, http://zenodo.org/record/373528

An Immunosensor Based on Au-Ag Bimetallic NPs Patterned on a Thermal Resistant Flexible Polymer Substrate for In-Vitro Protein Detection

Nanosensors based on flexible polymers have emerged as powerful tools for next generation smart devices in the recent years. Here, we report a facile protocol to fabricate an immunosensor supported by a thermally resistant flexible polymer substrate (polyarylene ether nitrile, PEN). The immunosensor is a localized surface plasmon resonance (LSPR) optical sensor for in-vitro protein detection based on anti-body coated gold-silver bimetallic nanoparticles (Au-Ag NPs) immobilized on a PEN substrate. Plasmonic spectroscopy and morphological characterization show that the Au-Ag NPs essentially exhibit a more uniform size distribution and higher quality factors than those from single-component Au NPs. Furthermore, it should be noted that the robust PEN substrate in this nanosensor acts a flexible substrate to support Au-Ag NPs and immobilize the nanoparticles via quick thermal annealing at 290 °C. Thanks to these merits, a prostate-specific antigen (PSA) concentration as low as 1 ng/mL can be specifically discriminated via the prepared PEN/Au-Au NPs, which confirms that the protocol reported in this work can be readily adapted for the construction of various flexible immunosensors for different applications

Atomic Mechanism of Dynamic Electrochemical Lithiation Processes of MoS₂ Nanosheets

Layered molybdenum disulfide (MoS₂) has been studied for decades for its diversity of structure and properties, where the structural dynamic evolution during lithium intercalation is an important but still indistinct, controversial topic. Here the electrochemical dynamic process of MoS₂ nanosheets upon lithium intercalation has been systematically investigated by <i>in situ</i> high-resolution transmission electron microscopy. The results indicate that the lithiated MoS₂ undergoes a trigonal prismatic (2H)-octahedral (1T) phase transition with a lithium ion occupying the interlayer S–S tetrahedron site in the 1T-LiMoS₂. A pseudoperiodic structural modulation composed of polytype superlattices is also revealed as a consequence of the electron–lattice interaction. Furthermore, the shear mechanism of the 2H-1T phase transition has been confirmed by probing the dynamic phase boundary movement. The <i>in situ</i> real-time characterization at atomic scale provides a great leap forward in the fundamental understanding of the lithium ion storage mechanism in MoS₂, which should be also of help for other transition metal dichalcogenides

Comparative Study of Thermodynamic Regulation Characteristics in a Dual-Tube Reactor with an External Heat Exchanger

A special dual-tube reactor-dual fluidized bed reactor (DFBR), including an external heat exchanger (EHE) and a bypass, was designed to solve the problems that the waste heat of the hot fluid cannot be fully utilized and the reaction temperature cannot be accurately adjusted. Two connection schemes of DFBR and EHE with their thermodynamic equilibrium models and algorithms were proposed, and the optimal scheme was obtained by comparing the outlet temperature and thermal load. The results of the thermodynamic and operating characteristics of the optimal scheme showed that the hot fluid and the cold fluid had positive and negative effects on the heat transfer process, respectively. Increasing the cold fluid mass flow rate in the main stream can enhance the thermal load of the system and increasing the cold fluid mass flow rate in the bypass helped to increase the thermal load of DFBR, even exceeding that of EHE. Adding a bypass can adjust temperature precisely and increasing the inlet temperature can more effectively increase the adjustment range of the reaction zone temperature. The experimental results showed that introducing a bypass can significantly reduce the calculation deviation (12.8%), which decreased with the increasing temperature