An acoustic tracking model based on deep learning using two hydrophones and its reverberation transfer hypothesis, applied to whale tracking

Acoustic tracking of whales’ underwater cruises is essential for protecting marine ecosystems. For cetacean conservationists, fewer hydrophones will provide more convenience in capturing high-mobility whale positions. Currently, it has been possible to use two hydrophones individually to accomplish direction finding or ranging. However, traditional methods only aim at estimating one of the spatial parameters and are susceptible to the detrimental effects of reverberation superimposition. To achieve complete whale tracking under reverberant interference, in this study, an intelligent acoustic tracking model (CIAT) is proposed, which allows both horizontal direction discrimination and distance/depth perception by mining unpredictable features of position information directly from the received signals of two hydrophones. Specifically, the horizontal direction is discriminated by an enhanced cross-spectral analysis to make full use of the exact frequency of received signals and eliminate the interference of non-source signals, and the distance/depth direction combines convolutional neural network (CNN) with transfer learning to address the adverse effects caused by unavoidable acoustic reflections and reverberation superposition. Experiments with real recordings show that 0.13 km/MAE is achieved within 8 km. Our work not only provides satisfactory prediction performance, but also effectively avoids the reverberation effect of long-distance signal propagation, opening up a new avenue for underwater target tracking

Comprehensive Structure and Functional Adaptations of the Yeast Nuclear Pore Complex [preprint]

Nuclear Pore Complexes (NPCs) mediate the nucleocytoplasmic transport of macromolecules. Here we provide a structure of the yeast NPC in which the inner ring is resolved by cryo-EM at - helical resolution to show how flexible connectors tie together different structural and functional layers in the spoke. These connectors are targets for phosphorylation and regulated disassembly in cells with an open mitosis. Moreover, some nucleoporin pairs and karyopherins have similar interaction motifs, which suggests an evolutionary and mechanistic link between assembly and transport. We also provide evidence for three major NPC variants that foreshadow functional specializations at the nuclear periphery. Cryo-electron tomography extended these studies to provide a comprehensive model of the in situ NPC with a radially-expanded inner ring. Our model reveals novel features of the central transporter and nuclear basket, suggests a role for the lumenal ring in restricting dilation and highlights the structural plasticity required for transport by the NPC

Role of Modified Atmosphere in Pest Control and Mechanism of Its Effect on Insects

Pests not only attack field crops during the growing season, but also damage grains and other food products stored in granaries. Modified or controlled atmospheres (MAs or CAs) with higher or lower concentrations of atmospheric gases, mainly oxygen (O2), carbon dioxide (CO2), ozone (O3), and nitric oxide (NO), provide a cost-effective method to kill target pests and protect stored products. In this review, the most recent discoveries in the field of MAs are discussed, with a focus on pest control as well as current MA technologies. Although MAs have been used for more than 30 years in pest control and play a role in storage pest management, the specific mechanisms by which insects are affected by and adapt to low O2 (hypoxia) and high carbon CO2 (hypercapnia) are not completely understood. Insect tolerance to hypoxia/anoxia and hypercapnia involves a decrease in aerobic metabolism, including decreased NADPH enzyme activity, and subsequently, decreases in glutathione production and catalase, superoxide dismutase, glutathione-S-transferase, and glutathione peroxidase activities, as well as increases in carboxyl esterase and phosphatase activities. In addition, hypoxia induces energy and nutrient production, and in adapted insects, glycolysis and pyruvate carboxylase fluxes are downregulated, accompanied with O2 consumption and acetate production. Consequently, genes encoding various signal transduction pathway components, including epidermal growth factor, insulin, Notch, and Toll/Imd signaling, are downregulated. We review the changes in insect energy and nutrient sources, metabolic enzymes, and molecular pathways in response to modified O2, CO2, NO, and O3 concentrations, as well as the role of MAs in pest control. This knowledge will be useful for applying MAs in combination with temperature control for pest control in stored food products

pH-Induced conformational changes of human bocavirus capsids

Human bocavirus 1 (HBoV1) and HBoV2 to-4 infect children and immunocompromised individuals, resulting in respiratory and gastrointestinal infections, respectively. Using cryo-electron microscopy and image reconstruction, the HBoV2 capsid structure was determined to 2.7-angstrom resolution at pH 7.4 and compared to the previously determined HBoV1, HBoV3, and HBoV4 structures. Consistent with previous findings, surface variable region III (VR-III) of the capsid protein VP3, proposed as a host tissue tropism determinant, was structurally similar among the gastrointestinal strains HBoV2 to-4, but differed from that of HBoV1 with its tropism for the respiratory tract. Toward understanding the entry and trafficking properties of these viruses, HBoV1 and HBoV2 were further analyzed as species representatives of the two HBoV tropisms. Their cell surface glycan-binding characteristics were analyzed, and capsid structures determined to 2.5-to 2.7-angstrom resolution at pHs 5.5 and 2.6, conditions normally encountered during infection. The data showed that glycans with terminal sialic acid, galactose, GlcNAc, or heparan sulfate moieties do not facilitate HBoV1 or HBoV2 cellular attachment. With respect to trafficking, conformational changes common to both viruses were observed under low-pH conditions localized to the VP N terminus under the 5-fold channel, in the surface loops VR-I and VR-V and specific side chain residues such as cysteines and histidines. The 5-fold conformational movements provide insight into the potential mechanism of VP N-terminal dynamics during HBoV infection, and side chain modifications highlight pH-sensitive regions of the capsid. IMPORTANCE Human bocaviruses (HBoVs) are associated with disease in humans. However, the lack of an animal model and a versatile cell culture system to study their life cycle limits the ability to develop specific treatments or vaccines. This study presents the structure of HBoV2, at 2.7-A resolution, determined for comparison to the existing HBoV1, HBoV3, and HBoV4 structures, to enable the molecular characterization of strain and genus-specific capsid features contributing to tissue tropism and antigenicity. Furthermore, HBoV1 and HBoV2 structures determined under acidic conditions provide insight into capsid changes associated with endosomal and gastrointestinal acidification. Structural rearrangements of the capsid VP N terminus, at the base of the 5-fold channel, demonstrate a disordering of a "basket" motif as pH decreases. These observations begin to unravel the molecular mechanism of HBoV infection and provide information for control strategies.Peer reviewe

Frontier and hot topics in home enteral nutrition based on CiteSpace bibliometric analysis

BackgroundThe benefits of home enteral nutrition (HEN) are increasingly recognized, with more scholars focusing on this field. This study aimed to comprehensively identify collaborative networks, analyze, and track research trends, focus on current hotspots, and accurately predict the forefront and focus of home enteral nutrition.MethodsA computer search of the Web of Science Core Collection (WoSCC) was conducted for studies related to home enteral nutrition published from January 1, 2004, to December 31, 2023, and select them in compliance with the PRISMA guidelines. The CiteSpace software was used for bibliometric visualization and comparative analysis of countries, institutions, journals, references, and keywords.ResultsA total of 1,113 documents were included, showing a steady annual increase in publication volume. The United States and the Mayo Clinic were the top publishing country and institution, with 302 and 41 papers, respectively. “CLIN NUTR” had the highest number of publications, totaling 221, while “ESPEN guideline on home enteral nutrition” was the most cited reference, with 43 citations. The most prolific author was Manpreet S with 29 papers.ConclusionThe management of HEN is a current research hotspot. The safety of HEN and how to improve patient compliance are critical areas for researchers to consider. Future research could focus on these aspects. The blurring of boundaries between hospital and home care and how to utilize telemedicine technologies to serve more patients deserve in-depth exploration. Researchers worldwide should combine their unique characteristics and advantages to strengthen international cooperation