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Open access

Zhengyao He, Qiang Shi and Shaoxuan Wu

Abstract

In underwater unmanned vehicles, complex acoustic transducer arrays are always used to transmitting sound waves to detect and position underwater targets. Two methods of obtaining low-sidelobe transmitting beampatterns for acoustic transmitting arrays of underwater vehicles are investigated. The first method is the boundary element model optimization method which used the boundary element theory together with the optimization method to calculate the driving voltage weighting vector of the array. The second method is the measured receiving array manifold vector optimization method which used the measured receiving array manifold vectors and optimization method to calculate the weighting vector. Both methods can take into account the baffle effect and mutual interactions among elements of complex acoustic arrays. Computer simulation together with experiments are carried out for typical complex arrays. The results agree well and show that the two methods are both able to obtain a lower sidelobe transmitting beampattern than the conventional beamforming method, and the source level for each transmitting beam is maximized in constraint of the maximum driving voltage of array elements being constant. The effect of the second method performs even better than that of the first method, which is more suitable for practical application. The methods are very useful for the improvement of detecting and positioning capability of underwater unmanned vehicles.

Open access

Li-Hui Lü and Qiang-Sheng Wu

Abstract

Replant disease refers to the result of monoculture-continuous repetitive planting of congeneric crops or coordinal crops in the same soil for many years. Such disease is recognized as one of the main limiting factors affecting plant growth and production of horticultural plants in many countries. As a result, replant disease in horticultural plants has become a world problem in agriculture and also a bottleneck restricting the sustainable development of agriculture. In general, replant disease results in unfavorable growth of horticultural plants, which is due to allelopathy, autotoxicity, and the imbalance of both soil physical-biochemical traits and soil microflora. An environmentally friendly contribution to this could be bio-controlled by beneficial microorganisms. Arbuscular mycorrhizal fungi, one of soil-inhabiting fungi, can form a symbiotic association in roots to mitigate the negative effects of replant disease in many horticultural plants. Moreover, arbuscular mycorrhizal fungi do not produce any environmental pollution in soils and are a potential biological control. The soil fungi could regulate better morphological, physiological and molecular levels in plants to respond to the disease. This review mainly outlined the current knowledge in mycorrhizal mitigation of replant disease in horticultural plants, which appears to be a promising strategy to improve growth of horticultural plants in replant soils.

Open access

Min Li, Yang-yang Wu and Zhi-qiang Guan

Abstract

In order to achieve the influence of different pretreatment methods on heat pump dried tilapia fillets, the effects of trehalose, ultrasound-assisted and freeze-thaw cycle assisted osmotic dehydration on the color, rehydration, texture and Ca2+-ATPase activity were investigated. Tilapia fillets (100 mm length × 50 mm width × 5 mm height) were first osmoconcentrated in a trehalose solution combined with 4°C under atmospheric pressure for 1 h, different power of ultrasound and freeze-thawing respectively, then heat pump dried. The results showed that under the same drying method, the comprehensive score of ultrasound in 400 Watt was best, compared to freeze-thaw, the ultrasound pretreatment had a significant (p<0.05) effect on the color and Ca2+-ATPase activity, but had no significant (p>0.05) effect on the rehydration and texture. However, both of them significantly (p<0.05) affected the quality in comparison to that of osmosis at 4°C. It indicates that suitable ultrasonic pretreatment conditions improve the quality of dried products effectively and the conclusion of this research provides reference for heat pump dried similar products.

Open access

Li-fei Sun, Qiang-qiang Wu, Zhi-hong Sun, Bing Han, Hong-feng Hao, Gui-chen Wang, Ming Li and Jin-biao Zhang

Abstract

Objective To observe the expression of inflammatory molecules in bone marrow immune cells of patients with immune-related hematocytopenia (IRH), and to investigate the immune mechanism and clinical significance of the disease.

Methods Total of 36 IRH patients were selected as observation group and 30 healthy people were taken as control group. Serum cytokines levels, activity of immunocytes and expression of HLA-DR were detected. Immune fluorescence was applied to observe the expression state of immunologic molecules and cytokines in IRH patients.

Results Serum cytokines were elevated in various degrees in observation group. Compared with the control group, the cytokines levels were significantly higher (P < 0.05). After treatement with immunosuppressive drugs, the serum levels of cytokines in observation group reduced to a level close to the control group. HLADR were upregulated in activated tissue basophils, eosinophils, dendritic cells (DC) and macrophages of bone marrow in IRH patients, and POX activity in these immunocytes of IRH was higher than that of the control group. Immune molecules were highly expressed in eosinophils, DC and macrophages.

Conclusions It is demonstrated that antibodies or self-reactive lymphocytes were produced in IRH marrow, which would cause lesions of hemocytes, and lead to pathological process finally. Structure of hematopoietic cells mutated and these cells might be acted as target cells of immunocytes in the pathological process. Immunocytes could secrete inflammatory factors and lead to immunologic injury of hemocyte.

Open access

Zheng-Shou Chen, Yeon-Seok Park, Li-ping Wang, Wu-Joan Kim, Meng Sun and Qiang Li

ABSTRACT

Aiming at accurately distinguishing modeless component and natural vibration mode terms from data series of nonlinear and non-stationary processes, such as Vortex-Induced Vibration (VIV), a new empirical mode decomposition method has been developed in this paper. The key innovation related to this technique concerns the method to decompose modeless component from non-stationary process, characterized by a predetermined ‘maximum intrinsic time window’ and cubic spline. The introduction of conceptual modeless component eliminates the requirement of using spurious harmonics to represent nonlinear and non-stationary signals and then makes subsequent modal identification more accurate and meaningful. It neither slacks the vibration power of natural modes nor aggrandizes spurious energy of modeless component. The scale of the maximum intrinsic time window has been well designed, avoiding energy aliasing in data processing. Finally, it has been applied to analyze data series of vortex-induced vibration processes. Taking advantage of this newly introduced empirical decomposition method and mode identification technique, the vibration analysis about vortex-induced vibration becomes more meaningful.

Open access

Yan Y. Wu, Hui R. Jia, Qiang Wang, Ping L. Dai, Qing Y. Diao, Shu F. Xu, Xing Wang and Ting Zhou

Abstract

China has the largest number of managed honey bee colonies globally, but there is currently no data on viral infection in diseased A. mellifera L. colonies in China. In particular, there is a lack of data on chronic bee paralysis virus (CBPV) in Chinese honey bee colonies. Consequently, the present study investigated the occurrence and frequency of several widespread honey bee viruses in diseased Chinese apiaries, and we used the reverse transcription-polymerase chain reaction (RT-PCR) assay. Described was the relationship between the presence of CBPV and diseased colonies (with at least one of the following symptoms: depopulation, paralysis, dark body colorings and hairless, or a mass of dead bees on the ground surrounding the beehives). Phylogenetic analyses of CBPV were employed. The prevalence of multiple infections of honey bee viruses in diseased Chinese apiaries was 100%, and the prevalence of infections with even five and six viruses were higher than expected. The incidence of CBPV in diseased colonies was significantly higher than that in apparently healthy colonies in Chinese A. mellifera aparies, and CBPV isolates from China can be separated into Chinese-Japanese clade 1 and 2. The results indicate that beekeeping in China may be threatened by colony decline due to the high prevalence of multiple viruses with CBPV.

Open access

Tao Lan, Bao-chun Chen, Li-ping Fu, Zhi-juan Li, Xiang-jun Wu and Nai-qiang Cui

Abstract

Intestinal barrier dysfunction, facilitating translocation of bacteria and bacterial products, plays an important role in the pathophysiology of liver cirrhosis and its complications. Intestinal defense system including microbial barrier, immunologic barrier, mechanical barrier, chemical barrier, plays an important role in the maintenance of intestinal function. Under normal circumstances, the intestinal barrier can prevent intestinal bacteria through the intestinal wall from spreading to the body. Severe infection, trauma, shock, cirrhosis, malnutrition, immune suppression conditions, intestinal bacteria and endotoxin translocation, can lead to multiple organ dysfunction. The intestinal microflora is not only involved in the digestion of nutrients, but also in local immunity, forming a barrier against pathogenic microorganisms. The derangement of the gut microflora may lead to microbial translocation, defined as the passage of viable microorganisms or bacterial products from the intestinal lumen to the mesenteric lymph nodes and other extraintestinal sites. In patients with cirrhosis, primary and intestinal flora imbalance, intestinal bacterial overgrowth, intestinal mucosal barrier dysfunction, endotoxemia is associated with weakened immunity.

Open access

Hong Shen, Qiang Deng, Rebecca Lao and Simon Wu

Abstract

In this paper, we focus on inventory management in a manufacturing company in China. This study aims to identify the key factors that influence inventory management practices, investigate efficient and effective inventory management approaches, and examine the impact of supplier cooperation on supply chain improvement. A case study approach is used to identify the key factors that influence inventory management in a factory. Efficient and effective inventory management practices are derived from the case study and may provide practical guidance for foreign manufacturers in China. This study provides a valuable tool for identifying the key factors in inventory management which can be applied to similar problems encountered in actual manufactories.