712 research outputs found
Effect of cadmium on the defense response of Pacific oyster Crassostrea gigas to Listonella anguillarum challenge
Heavy metal pollution can affect the immune capability of organisms. We evaluated the effect of cadmium (Cd) on the defense responses of the Pacific oyster Crassostrea gigas to Listonella anguillarum challenge. The activities of several important defensive enzymes, including superoxide dismutase (SOD), glutathione peroxidase (GPx), acid phosphatase (ACP), Na+, K+ -ATPase in gills and hepatopancreas, and phenoloxidase-like (POL) enzyme in hemolymph were assayed. In addition, the expression levels of several genes, including heat shock protein 90 (HSP90), metallothionein (MT), and bactericidal/permeability increasing (BPI) protein were quantified by fluorescent quantitative PCR. The enzyme activities of SOD, ACP, POL, and GPx in hepatopancreas, and the expression of HSP90 were down-regulated, whereas GPx activity in the gill, Na+, K+-ATPase activities in both tissues, and MT expression was increased in Cdexposed oysters post L. anguillarum challenge. However, BPI expression was not significantly altered by co-stress of L. anguillarum infection and cadmium exposure. Our results suggest that cadmium exposure alters the oysters' immune responses and energy metabolism following vibrio infection.Heavy metal pollution can affect the immune capability of organisms. We evaluated the effect of cadmium (Cd) on the defense responses of the Pacific oyster Crassostrea gigas to Listonella anguillarum challenge. The activities of several important defensive enzymes, including superoxide dismutase (SOD), glutathione peroxidase (GPx), acid phosphatase (ACP), Na+, K+ -ATPase in gills and hepatopancreas, and phenoloxidase-like (POL) enzyme in hemolymph were assayed. In addition, the expression levels of several genes, including heat shock protein 90 (HSP90), metallothionein (MT), and bactericidal/permeability increasing (BPI) protein were quantified by fluorescent quantitative PCR. The enzyme activities of SOD, ACP, POL, and GPx in hepatopancreas, and the expression of HSP90 were down-regulated, whereas GPx activity in the gill, Na+, K+-ATPase activities in both tissues, and MT expression was increased in Cdexposed oysters post L. anguillarum challenge. However, BPI expression was not significantly altered by co-stress of L. anguillarum infection and cadmium exposure. Our results suggest that cadmium exposure alters the oysters' immune responses and energy metabolism following vibrio infection
Joint Communication and Computation Design in Transmissive RMS Transceiver Enabled Multi-Tier Computing Networks
In this paper, a novel transmissive reconfigurable meta-surface (RMS)
transceiver enabled multi-tier computing network architecture is proposed for
improving computing capability, decreasing computing delay and reducing base
station (BS) deployment cost, in which transmissive RMS equipped with a feed
antenna can be regarded as a new type of multi-antenna system. We formulate a
total energy consumption minimization problem by a joint optimization of
subcarrier allocation, task input bits, time slot allocation, transmit power
allocation and RMS transmissive coefficient while taking into account the
constraints of communication resources and computing resources. This formulated
problem is a non-convex optimization problem due to the high coupling of
optimization variables, which is NP-hard to obtain its optimal solution. To
address the above challenging problems, block coordinate descent (BCD)
technique is employed to decouple the optimization variables to solve the
problem. Specifically, the joint optimization problem of subcarrier allocation,
task input bits, time slot allocation, transmit power allocation and RMS
transmissive coefficient is divided into three subproblems to solve by applying
BCD. Then, the decoupled three subproblems are optimized alternately by using
successive convex approximation (SCA) and difference-convex (DC) programming
until the convergence is achieved. Numerical results verify that our proposed
algorithm is superior in reducing total energy consumption compared to other
benchmarks
Information-Theoretic Limits of Integrated Sensing and Communication with Correlated Sensing and Channel States for Vehicular Networks
In connected vehicular networks, it is vital to have vehicular nodes that are
capable of sensing about surrounding environments and exchanging messages with
each other for automating and coordinating purpose. Towards this end,
integrated sensing and communication (ISAC), combining both sensing and
communication systems to jointly utilize their resources and to pursue mutual
benefits, emerges as a new cost-effective solution. In ISAC, the hardware and
spectrum co-sharing leads to a fundamental tradeoff between sensing and
communication performance, which is not well understood except for very simple
cases with the same sensing and channel states, and perfect channel state
information at the receiver (CSIR). In this paper, a general point-to-point
ISAC model is proposed to account for the scenarios that the sensing state is
different from but correlated with the channel state, and the CSIR is not
necessarily perfect. For the model considered, the optimal tradeoff is
characterized by a capacity-distortion function that quantifies the best
communication rate for a given sensing distortion constraint requirement. An
iterative algorithm is proposed to compute such tradeoff, and a few non-trivial
examples are constructed to demonstrate the benefits of ISAC as compared to the
separation-based approach
The Regenerating Gene Iα Is Overexpressed in Atrophic Gastritis Rats with Hypergastrinemia
The role of gastrin on the development of atrophic gastritis (AG) and its relationship with the expression of RegIα in vivo remain unclear. We established experimental AG in rats by combination administration with sodium salicylate, alcohol, and deoxycholate sodium. The mean score of inflammation in gastric antrum in AG rats was significantly elevated (P < 0.05), while the number of glands dramatically decreased (P < 0.05). In addition, the cell proliferation in gastric glands was increased in experimental AG rats, as determined by immunohistochemistry staining of PCNA and GS II. The level of serum gastrin in AG rats was significantly elevated relative to that of normal rats (P < 0.01). Moreover, the expression of RegIα protein and its receptor mRNA was increased in gastric tissues in AG rats (P < 0.05). Taken together, we demonstrated that the overexpression of Reglα is related with hypergastrinemia in AG rats
Uplink Transceiver Design and Optimization for Transmissive RMS Multi-Antenna Systems
In this paper, a novel uplink communication for the transmissive
reconfigurable metasurface (RMS) multi-antenna system is investigated.
Specifically, a transmissive RMS-based receiver equipped with a single
receiving antenna is first proposed, and a far-near field channel model is also
given. Then, in order to maximize the system sum-rate, we formulate a joint
optimization problem over subcarrier allocation, power allocation and RMS
transmissive coefficient design. Since the coupling of optimization variables,
the problem is non-convex, so it is challenging to solve it directly. In order
to tackle this problem, the alternating optimization (AO) algorithm is used to
decouple the optimization variables and divide the problem into two subproblems
to solve. Numerical results verify that the proposed algorithm has good
convergence performance and can improve system sum-rate compared with other
benchmark algorithms.Comment: arXiv admin note: text overlap with arXiv:2109.0546
OMAE2006-92140 CHARACTERISTICS OF CURRENT GENERATION SYSTEM IN DEEPWATER OFFSHORE BASIN
ABSTRACT The current generation system in deepwater offshore basin is important for the correct modeling of ocean environment. It is generally considered to be a challenge to obtain uniform and stable current flow in the basin. As technical assurance numerical and experimental studies are performed to investigate the characteristics of the deepwater current generation in the basin. Reynolds-Averaged Navier-Stokes (RANS) equations and the standard k-ε turbulence model are adopted to simulate the current generation system numerically. In addition a 1:10 scaled model test is also performed. In both numerical and experimental studies horizontal and vertical current velocity profiles, turbulence levels and pressure losses during the current recirculation etc. are studied. It is concluded that the perforated walls are key components of the current generation system. In addition various vertical current velocity profiles can be realized in the basin
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