Search

The pollution of heavy metals in agricultural soil poses a dangerous health risk to nearby residents. This study presents a method to assess the health risks of heavy metal pollution using Monte Carlo simulations. Soil samples from an agate dyeing village were collected and their heavy metal contents were analyzed. The results indicate the contamination of heavy metals in the study area soil, the singlefactor index values of Pb, Cu, Cr, and Ni were found to indicate mild pollution, and the Nemerow complex index values of all investigated metals were ranked at level IV, indicating moderate pollution. The health assessment indicates an unacceptable total carcinogenic risk for adults and children and noncarcinogenic hazard quotient for adults. Oral ingestion was found to be the main exposure pathway, and the most sensitive factors were the adherence factor, soil ingestion rate, and body weight. [ABSTRACT FROM AUTHOR]

The article reports that Fibroblast growth factor (FGF2) is a potent mitogen that is secreted through an unconventional secretory pathway by crossing plasma membrane directly, which enhances accessibility to FGF2 binding and alters membrane property to increase FGF2 translocation.

In dairy herd management, it is significant and irreplaceable for veterinarians to make rapid and effective diagnosis of dairy cow diseases. Based on electronic medical records, deep learning (DL) has been widely used to support clinical decisions for humans. However, this method is rarely adopted in veterinary diagnosis. In addition, most DL models are driven by large datasets, failing to utilize the knowledge acquired by veterinarians in subjective experience, which is critical to disease diagnosis. To address these problems, this paper proposes a DL method for disease diagnosis of dairy cow: convolutional neural network (CNN) based on knowledge graph and transfer learning (KGTL_CNN). Firstly, the structural knowledge was extracted from a knowledge graph of dairy cow diseases, and treated as part of the inputs to the CNN based on knowledge graph (KG_CNN). Then, the model performance was enhanced through pre-training by transfer learning. To verify its performance, experiments were carried out on dairy cow clinical datasets. The results show that our model performed satisfactorily on disease diagnosis: the KG_CNN and KGTL_CNN achieved an F1- score of 85.87% and 86.77%, respectively, higher than that of typical CNN by 6.58% and 7.7%. The research results greatly promote the effective, fast, and automatic clinical diagnosis of dairy cow diseases. [ABSTRACT FROM AUTHOR]

Embedding small devices into everyday objects like toasters and coffee mugs creates a wireless network of objects. These embedded devices can contain a description of the underlying objects, or other user defined information. In this paper, we present Snoogle, a search engine for such a network. A user can query Snoogle to find a particular mobile object, or a list of objects that fit the description. Snoogle uses information retrieval techniques to index information and process user queries, and Bloom filters to reduce communication overhead. Security and privacy protections are also engineered into Snoogle to protect sensitive information. We have implemented a prototype of Snoogle using off-the-shelf sensor motes, and conducted extensive experiments to evaluate the system performance. [ABSTRACT FROM AUTHOR]

Given the extremely limited hardware resources on sensor nodes and the inclement deploying environment, the adversary Denial-of-Service (DoS) attack becomes a serious security threat toward wireless sensor networks. Without adequate defense mechanism, the adversary can simply inundate the network by flooding the bogus data packets, and paralyze the partial or whole sensor network by depleting node battery power. Prior work on false packet filtering in sensor networks are mostly based on symmetric key schemes, with the concern that the public key operations are too expensive for the resource constrained sensors. Recent progress in public key implementations on sensors, however, has shown that public key is already feasible for sensors. In this paper, we present PDF, a Public-key based false Data Filtering scheme that leverages Shamir’s threshold cryptography and Elliptic Curve Cryptography (ECC), and effectively rejects 100% of false data packets. We evaluate PDF by real world implementation on MICAz motes. Our experiment results support the conclusion that PDF is practical for real world sensor deployment. [ABSTRACT FROM AUTHOR]

Abstract  In this work, by a combination of controlled ring-opening polymerization (CROP) and click chemistry, we report a facile and useful method to synthesize linear poly(ε-caprolactone)@attapulgite nanocomposites with well-defined structures. For this, first, the chlorine-terminated attapulgite was prepared by the self-assembly of 3-chloropropyltrimethoxysilane from the surfaces of attapulgite. And then, the terminal chlorines of modified attapulgite were substituted with azido groups. As the second step, linear propargyl-terminated poly(ε-caprolactone) (PCLs) with different molecular weights were synthesized by the CROP of ε-CL monomer in toluene with stannous octoate as a catalyst and propargyl alcohol as an initiator. The structural characteristics of the obtained linear PCLs have been determined by 1H NMR and gel permeation chromatography analysis. Finally, the azido-terminated attapulgite was reacted with propargyl-terminated PCLs via the click reaction. [ABSTRACT FROM AUTHOR]

A 1 kHz femtosecond double-pulse sequence irradiation is used to study the temporal evolution of nanograting in fused silica by controlling the delay times and polarization combinations of two independent beams from a Mach–Zehnder interferometer. A lateral laser-scan experiment with speed at 5 µm s−1 and each pulse energy of 1 µJ is firstly performed with the delay time from sub-picosecond to 10 ps, and then the written nanostructures are systematically studied under a cross-polarized microscope because the intensity of birefringence signal nearly corresponds to optical retardance and development level of the induced nanograting. The trend shows that the induced nanogratings can continue developing with a decrease of delay time in the case of the linear polarization pulse arriving before. In another vertical laser-scan experiment at the same speed and pulse energy, the morphologies of nanogratings embedded in the lines are characterized by scanning electron microscope after mechanical polishing and chemical etching. The self-organized patterns have a commonly spatial period of 200–300 nm and the orientation is always perpendicular to the polarization of the first laser pulse, and the second pulse in each sequence seems to promote the as-formed nanograting developing further even if the polarized direction is different from the previous pulse. These new findings verify again that a localized memory effect can make positive feedback to reinforce the patterned nanostripes. In that process, the impact ionization from the seed electrons left by the first pulse excitation and the photoionization of self-trapped excitons with lower ionization threshold results in an increase of the re-excited carriers during the second pulse irradiation and the subsequent development of the as-formed nanograting. Our result provides further proofs for understanding the physical mechanism of nanograting strongly connection with the interplay on multiple ionization channels. [ABSTRACT FROM AUTHOR]

Hyperlipidemia characterized by high blood levels of free fatty acids (FFAs) is important for the progression of inflammatory cardiovascular diseases. Integrin β1 is a transmembrane receptor that drives various cellular functions, including differentiation, migration, and phagocytosis. However, the underlying mechanisms modifying integrin β1 protein and activity in mediating monocyte/macrophage adhesion to endothelium remain poorly understood. In this study, we demonstrated that integrin β1 protein underwent S-nitrosylation in response to nitrosative stress in macrophages. To examine the effect of elevated levels of FFA on the modulation of integrin β1 expression, we treated the macrophages with a combination of oleic acid and palmitic acid (2:1) and found that FFA activated inducible nitric oxide synthase/ nitric oxide and increased the integrin β1 protein level without altering the mRNA level. FFA promoted integrin β1 S-nitrosylation via inducible nitric oxide synthase/nitric oxide and prevented its degradation by decreasing binding to E3 ubiquitin ligase c-Cbl. Furthermore, we found that increased integrin α4β1 heterodimerization resulted in monocyte/macrophage adhesion to endothelium. In conclusion, these results provided novel evidence that FFA-stimulated N--O stabilizes integrin β1 via S-nitrosylation, favoring integrin α4β1 ligation to promote vascular inflammation. [ABSTRACT FROM AUTHOR]

Using sophoridine 1 and chalcone 3 as the lead compounds, a series of novel α, β-unsaturated sophoridinic derivatives were designed, synthesized, and evaluated for their in vitro cytotoxicity. Structure-activity relationship (SAR) analysis indicated that introduction of α, β-unsaturated ketone moiety and heterocyclic group might significantly enhance anticancer activity. Among the compounds, 2f and 2m exhibited potential effects against HepG-2 and CNE-2 human cancer cell lines. Furthermore, molecular docking studies were performed to understand possible docking sites of the molecules on the target proteins and the mode of binding. This work provides a theoretical basis for structural optimizations and exploring anticancer pathways of this kind of compound. [ABSTRACT FROM AUTHOR]

Flooding is a fundamental file search operation in unstructured peer-to-peer (P2P) file sharing systems, in which a peer starts the file search procedure by broadcasting a query to its neighbors, who continue to propagate it to their neighbors. This procedure repeats until a time-to-live (TTL) counter is decremented to 0. Flooding can seriously limit system scalability, because the number of redundant query messages grows exponentially during the message propagation. Our study shows that more than 70 percent of the generated messages are redundant in a flooding with a TTL of 7 in a moderately connected Gnutella network. Existing efforts to address this issue have been focused on limiting the use of the flooding operation. We propose a new flooding scheme, called LightFlood, with the objective of minimizing the number of redundant messages and retaining a similar message-propagating scope as that of the standard flooding. In the scheme, each peer keeps track of the connectivities of every immediate and next indirect neighbor peers, which can be acquired locally. LightFlood identifies the neighbor with the highest connectivity and uses the link to that neighbor to form a suboverlay within the existing P2P overlay. In LightFlood, flooding is divided into two stages. The first stage is a standard flooding with a limited number of TTL hops, where a message can spread to a sufficiently large scope with a small number of redundant messages. In the second stage, message propagating is only conducted along the suboverlay, significantly reducing the number of redundant messages. Our analysis and simulation experiments show that the LightFlood scheme provides a low-overhead broadcast facility that can be effectively used in P2P search. For example, compared with standard flooding with seven TTL hops, we show that LightFlood with an additional two to three hops can reduce up to 69 percent of the flooding messages and retain the same flooding scope. We believe that LightFlood can be widely used as a core mechanism for efficient message broadcasting in P2P systems due to its near-optimal performance. [ABSTRACT FROM AUTHOR]