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The first record of Hallucigenia-like lobopodians from the lower Jince Formation (Cambrian, Miaolingian) of the Příbram–Jince Basin
No full textA fossil interpreted as a long-legged lobopodian animal (Hallucigenia? sp.) is described from the middle Cambrian (Miaolingian) Jince Formation of the Příbram–Jince Basin (Barrandian area, Czech Republic). The fossil shows a long vermiform trunk, at least twenty-five long thin lobe-like appendages indicating the ventral side, and the bases of at least 12 thin spines protruding dorsally. Palynological processing of fine-grained rock samples from ca. 100 m higher in the section yielded several tens of small carbonaceous fossils attributable to armoured lobopodians alongside wiwaxiid sclerites and additional abundant organic-walled microfossils. The Bohemian specimen and recent finds of rare lobopodians in Australia, China, and the USA, together with many occurrences of isolated spines interpreted as belonging to hallucigeniids, demonstrate that lobopodians were much more geographically widespread than previously thought. The Bohemian macrofossil is the youngest known occurrence of a hallucigeniid; this specimen and the microfossil material extend the stratigraphic range of the group within the traditional early to middle Cambrian interval
The first fossil loggerhead sea turtle (Cheloniidae: Caretta) from the North Pacific and its nannofossil biostratigraphy
No full textThe Taiwan waters (western North Pacific) include five sea turtle species without an associated fossil record. Here, we describe the first fossil sea turtle from Taiwan. This fossil material is a partial hypoplastron from the uppermost Yuching Shale in Tainan. The preserved morphology of this partial hypoplastron shows a slightly curved medial margin, a deep lateral notch, and a wide sutural anterior margin, indicating a taxonomic affinity to the genus Caretta. In comparison with extant Caretta, the preserved hypoplastral width at the sutural level (130.85 mm) suggests that this fossil belongs to an old subadult cf. Caretta. In addition, we also analyzed fossil foraminifera from the matrix of this hypoplastron, suggesting that the depositional environment was a continental shelf no more than 100 m deep. We further examined the nannofossils and found more than 200 calcareous nannofossils, including index fossils, such as Pseudoemiliania lacunosa, Helicosphaera sellii, and large Gephyrocapsa sp. (> 5.5 μm), corresponding to NN19a nannofossil biozone (Early Pleistocene in age). Given the first occurrence of the large Gephyrocapsa sp. and the last occurrence of Helicosphaera sellii, we narrowed down the age of this Pleistocene sea turtle from Taiwan to 1.57 to 1.28 million years ago. Our discovery of this Pleistocene sea turtle fossil represents not only the first cheloniid fossil in Taiwan but also the first well-dated fossil sea turtle from the global Pleistocene. The Taiwan waters during the Early Pleistocene may be a paleo-foraging ground for cf. Caretta, and future fieldwork and analysis should reveal a more detailed evolutionary history of sea turtles in the North Pacific. Our results also highlight the potential for more paleontological progress from Taiwan
Fossil deep-sea snapper (Actinopterygii: Lutjanidae) from the Last Interoceanic Central American Deep Strait (LICADS)
No full textAlthough lutjanid snappers are widely distributed and diverse marine fishes living in tropical America (the Central Western Atlantic and Central Eastern Pacific), no fossil skeletons of Lutjanidae are reported from the Neogene. Here we describe the first specimens of Lutjanidae from the Chagres Sandstone Member of the late Miocene Chagres Formation, located on the Panamanian Caribbean coast. The skull and the postcranial bones of the specimen indicate that it represents an undescribed species of the genus Etelis. The new taxon is characterized by a moderately deep skull with dorsal surface slanted 29 ͦ relative to the horizontal axis, a large orbit, an opercle with a distal margin forming a wide spine, a posterior margin of the preopercle that is serrated without prominent spines, premaxilla and dentary with a single row of dental alveoli. The mouth is slightly oblique, and the body is elongate and slender. The dorsal fin aligns with the pectoral fins, while the pelvic fin is short and does not reach the anal fin. Oceanic water interchange and species dispersal associated with marine currents flowing eastward through the Central American Seaway appear to have driven the diversification of the American Lutjanidae prior to the complete closure of the Panama Isthmus. The palaeoceanographic changes driven by this geological event triggered a faunal turnover that shaped the extant marine diversity in the Caribbean. The newly described lutjanid is associated to a markedly bathyal (200–500 m) archipelagic and interoceanic seaway strait in central Panama (the Last Interoceanic Central American Deep Strait, LICADS)
Taxonomic study of the genus Erechthias (Lepidoptera, Tineidae) from the Ogasawara Islands, with two new records and four new species
No full textThis study reviewed the genus Erechthias Meyrick, 1880 on the Ogasawara Islands, Japan with regards to eight recognized species, two of which were known (E. itoi Moriuti & Kadohara, 1994 and E. zebrina (Butler, 1881)), two of which are newly recorded (E. minuscula (Walsingham, 1897) and E. atririvis (Meyrick, 1931)), and four of which are new species (E. mirabilis sp. nov., E. oculus sp. nov., E. flavimacula sp. nov., and E. nidumicola sp. nov.). Photographs of adult specimens and of their genitalia as well as illustrations of wing venation are provided. A preliminary phylogenetic tree based on mitochondrial DNA (the partial COI region, DNA barcode region) includes seven Erechthias species. Furthermore, haplotype networks were also constructed using DNA barcode regions for three species distributed across three or more island groups (Mukojima Islands, Chichijima Islands, Hahajima Islands, and other Islands). All examined E. flavimacula sp. nov. and E. nidumicola sp. nov. had unique haplotypes and were divided into three units corresponding to the group of islands
In silico and in vitro studies of gemcitabine derivatives as anticancer agents
No full textCancer remains one of the leading causes of death globally and is expected to increase in incidence. The present investigation aimed to evaluate the anticancer efficacy of gemcitabine derivatives on MCF7, A549, and PC3 cell lines. Compounds Com. 10 and Com. 16 were the most potent, with IC₅₀ values of 9.45, 6.93, and 12.09 µM (Com. 10) and 12.23, 6.60, and 21.57 µM (Com. 16) for the three cell lines, showing a better response compared to the reference drug gemcitabine. Com. 9 and Com. 14 were also moderately active, preferentially on A549 and PC3. Com. 16 showed strong binding with the active residues as determined by molecular docking. Com. 16 bound to key cancer targets Vav1 (6NEW), ERK2 (4ZXT), and CYP3A4 (7LXL), with docking scores of −191.72, −187.66, and −221.08 kcal/mol, respectively. These interactions were electrostatic, hydrophobic, and π-type, similar to those induced by gemcitabine. Several other compounds also demonstrated good docking scores (−160 to −180 kcal/mol), and eight protein–ligand complexes emerged as leads. Moreover, ADME and physicochemical analyses of the top six active compounds indicated good drug-likeness and a favorable PK profile compared to gemcitabine
Taxonomic notes of the cobweb spider genus Platnickina Koçak & Kemal, 2008 (Araneae, Theridiidae, Theridiinae), with descriptions of two new species from southern China
No full textBased on specimens collected from southern China, two new species of Platnickina Koçak & Kemal, 2008 are described: P. submaculata Hu & Liu, sp. nov. (male, female) and P. yoshidai Hu & Liu, sp. nov. (male). Two new combinations, transferred from Theridion Walckenaer, 1805, are proposed: P. obscuratum (Zhu, 1998), comb. nov. and P. xianfengense (Zhu & Song, 1992), comb. nov. Three new species groups within Platnickina are established based on morphological characteristics: antoni group, maculata group, and sterninotata group. In addition, we discuss the relationships between Platnickina and the genera Chrosiothes Simon, 1894, Coleosoma O. Pickard-Cambridge, 1882, Simitidion Wunderlich, 1992, and Theridion
Residual Energy-Aware Fuzzy-Based Clustering Algorithm for Underwater Wireless Sensor Networks
No full textIn the field of underwater exploration and research, Underwater Wireless Sensor Networks (UWSNs) play a vital role in understanding the marine environment, oceanography, and marine biology. A key strategy used in UWSNs to aggregate sensor nodes and improve network performance while extending battery life through lower energy usage is clustering. However, available clustering algorithms do not specifically address all the underwater problems, viz., communication is constrained by the limited bandwidth and high latency of acoustic signals, while energy consumption is critical due to the difficulty of recharging or replacing underwater batteries. The harsh underwater environment, with varying pressure, salinity, and movement, affects sensor performance and durability. Accurate localization is difficult without GPS and relies on less precise acoustic methods. So, this paper proposes a Residual Energy-Aware Fuzzy-Based Clustering Algorithm (REAFCA) for UWSNs which presents a novel framework intended to improve network performance and address issues with energy usage. For effective data routing, the REAFCA dynamically arranges clusters based on important factors such as node rank, radius, threshold, angular velocity, and residual energy. To maximize leadership inside the clusters, the adaptive threshold method makes sure that only superior cluster heads are chosen. The algorithm also incorporates dynamic range changes for communication to adapt to changing network circumstances. This algorithm mainly focuses on clustering in an underwater environment while improving the energy efficiency and network life of the nodes. Simulation results demonstrate the superiority of the proposed algorithm over K-means, K-meansA, LEACH, PEGASIS, HEED, DB-SCAN and HEER algorithms in terms of energy efficiency and throughput while achieving comparable average delay
Morphological and phylogenetic analyses reveal two new species of Neohelicomyces (Tubeufiales, Tubeufiaceae) from China
No full textNeohelicomyces is a genus of helicosporous hyphomycetes with the potential to produce bioactive secondary metabolites. During a survey of helicosporous fungi in Guizhou and Hainan provinces, southern China, four isolates were obtained from both freshwater and terrestrial habitats. Based on combined analyses of multigene phylogenetic data (ITS, LSU, tef1-α, and rpb2) and morphological characteristics, two novel species, Neohelicomyces aquisubtropicus and N. wuzhishanensis, are proposed. Detailed descriptions, illustrations, and phylogenetic analyses of the new taxa are presented. Additionally, a checklist of currently accepted Neohelicomyces species supported by molecular data is provided
Acacia invasion triggers cascading effects above- and belowground in fragmented forests
No full textInvasive alien plants like Acacia species are key drivers of ecosystem change, with considerable effects on forest structure, nutrient cycling, and biodiversity. In the Mediterranean region, which is already vulnerable to challenges such as anthropogenic forest fragmentation, Acacia species have become dominant invasive plants at the landscape scale. In this study, we explored the effects of Acacia dealbata Link, and Acacia melanoxylon R. Br. to a lower extent, in a fragmented forest landscape in Central Portugal. We hypothesised that Acacia invasion would alter vegetation structure, litter, soil, and springtail communities, with cascading effects on ecosystem dynamics. We established 25 sampling points within a 25 km2 grid to collect data on Acacia invasion status, vegetation structure (cover of different plant layers and species richness), litter and soil quality (litter C/N ratio and soil organic carbon), and springtail communities (abundances of epigeic, hemiedaphic, and euedaphic springtails). We considered an Acacia invasion gradient as a continuous variable calculated with the sum of the covers of A. dealbata and A. melanoxylon divided by the total tree cover to study the combined effect of the two species. High levels of Acacia invasion were associated with reduced herb cover and plant species richness. Moreover, as Acacia invasion intensified, there was a significant decrease in the litter C/N ratio, and an increase in soil organic carbon. Subsequently, these Acacia-induced impacts triggered cascading effects on the relationships between shrub cover, litter and soil quality, and springtail functional structure. These findings showed that even low levels of Acacia invasion altered above- and belowground dynamics, thereby highlighting the cascading impacts of these invasive alien plant species on ecosystem functioning. Prioritizing early intervention in areas with smaller infestations (i.e., especially in fragmented landscapes like those in Central Portugal) can help prevent further spread and impacts of both A. dealbata and A. melanoxylon
Association between the time for contrast to pass through the myocardium, risk profile and hemodynamic parameters
No full textIntroduction: The time for contrast to pass through the myocardium (TCPM) is a novel fluoroscopic method proposed for the assessment of coronary microcirculation in patients with non-significant epicardial coronary artery disease. Aim: This study aims to determine the mean TCPM in patients with angina and non-obstructive coronary arteries (ANOCA) and to analyze its relationship with hemodynamic parameters, myocardial mass, and traditional cardiovascular risk factors. Materials and methods: Sixty-two patients with typical angina referred for invasive coronary angiography were enrolled in this prospective observational study. The mean TCPM was measured in all patients. A linear regression analysis was performed to identify independent predictors of TCPM. Results: The mean TCPM was 4.99±1.01 seconds, with values ranging from 3.1 to 7.7 seconds. Regression analysis identified hypertension (p=0.019) as a positive predictor, while female sex (p=0.040) and mean arterial pressure (p=0.009) showed negative associations with TCPM. Traditional cardiovascular risk factors, including dyslipidemia, diabetes, smoking, and age, were not significantly associated with TCPM. Conclusion: A positive association was observed between TCPM and hypertension, while mean arterial pressure and female sex showed an inverse relationship with this parameter. TCPM is a technically simple and reproducible method that could have potential applications in the diagnosis of patients with angina and non-obstructive coronary arteries