Zhanjiang City Research Articles

Dewatering of a 32.55 m Deep Foundation Pit in MAMA Under Leakage Risk Conditions

A 2,250 mm whirlpool foundation pit is located in Donghai Island, Zhanjiang City, Guangdong Province, China. The layers of the island are composed of multi-aquifers and multi-aquitards (MAMA). The aquifers are intersected by partial aquitard lenses. A large confined aquifer is frequently interbedded and separated into several sub-confined aquifers by partial aquitards. In the 2,250 mm foundation pit, the water level of two confined aquifers was reduced to satisfy excavation requirements and prevent water inrush. Construction of the 32.55 m deep foundation pit encountered MAMA and potential defects of the diaphragm wall. The pumping wells in the second confined aquifer were used to reduce the water level to ensure the safety of bottom excavation. The pumping wells in the first confined aquifer were used to reduce the water level under emergency conditions to prevent potential water inrush and piping from the defects of the diaphragm wall. Field pumping tests and numerical simulations were performed to determine the risk of leakage and verify the capability of the pumping wells to reduce the water level. Quicksand occurred during shallow excavation because of leakage although the confined aquifer had been cut off and pumped for a long time. Three pumping wells were installed to reduce the water level. When the foundation pit was excavated to a depth of 24 m, water inrush occurred at the middle of the pit bottom although the water level of the dewatered aquifer had been reduced to below the excavation face. A 90 m deep borehole was found where the underlying confined aquifer below the first aquifer induced the water inrush. Although the upper water level was reduced, the high water level in the deep part still induced water inrush. The pumping wells in the second aquifer were all opened, and the water level of the underlying confined aquifer was reduced. After the water level was reduced to below the pit bottom, the borehole was filled, and the water inrush stopped. However, water inrush occurred on the cracks of the diaphragm wall as predicted. The pre-installed pumping wells were opened to control the water inrush. The deepest foundation pit on the island was constructed successfully after dealing with the water inrush and leakages.

A self-cited pixel summation based image encryption algorithm* *Project supported by the National Natural Science Foundation of China (Grant Nos. 61602124, 61273021, 11526057, and 11301091), the Natural Science Foundation of Guangdong Province, China (Grant Nos. 2016A030310333, 2015A030313614, and 2015A030313620), the Science & Technology Planning Projects of Zhanjiang City, China (Grant Nos. 2015B01098 and 2015B01051), the Project Foundation of Chongqing Municipal

In this paper, a novel image encryption algorithm is presented based on self-cited pixel summation. With the classical mechanism of permutation plus diffusion, a pixel summation of the plain image is employed to make a gravity influence on the pixel positions in the permutation stage. Then, for each pixel in every step of the diffusion stage, the pixel summation calculated from the permuted image is updated. The values from a chaotic sequence generated by an intertwining logistic map are selected by this summation. Consequently, the keystreams generated in both stages are dependent on both the plain image and the permuted image. Because of the sensitivity of the chaotic map to its initial conditions and the plain-image-dependent keystreams, any tiny change in the secret key or the plain image would lead to a significantly different cipher image. As a result, the proposed encryption algorithm is immune to the known plaintext attack (KPA) and the chosen plaintext attack (CPA). Moreover, experimental simulations and security analyses show that the proposed permutation-diffusion encryption scheme can achieve a satisfactory level of security.

Effects of PM2.5 on the differentiation of splenic CD4+ T lymphocyte of acute asthma mice

Objective To evaluate the effects of PM2.5 on the differentiation of splenic CD4+ T lymphocytes in acute asthma mice. Methods (1) Mouse models of acute asthma were established by ovalbumin (OVA) sensitization and challenge.(2) PM2.5 was collected in the urban area of Zhanjiang city under heavy traffic and serious air pollution from total suspended particulate(TSP) mid-flow sampler and multistage particles cutters and the dry powder of PM2.5 was prepared.(3) Specific-pathogen free Balb/c mice, female, at 6 to 8 weeks of age were randomly divided into 8 groups (8 mice each group): a negative control group (NC group), asthma control group (AC group), sensitized mice treated with different doses of PM2.5 groups (SP groups) and asthmatic mice treated with different doses of PM2.5 groups (AP groups). SP groups and AP groups were respectively divided into 3 subgroups according to the dose of PM2.5.The AC group, SP groups and AP groups were sensitized on D0, D7 and D14, and the NC group was treated with NS as controls.The SP1/AP1 group, SP2/AP2 group and SP3/AP3 group were respectively given 50 μL PM2.5 suspension.NC group and AC group were instilled with NS as controls.AC group and AP groups were challenged by aerosol of OVA, and NC group and SP group were treated with NS as controls.Twenty-four hours after last challenge, all the mice were sacrificed, and the percentage of regulatory T cells(Treg), T helper cell type 1(Th1), Th2 and Th17 of splenic CD4+ T lymphocytes was detected by flow cytometry (FCM). Results (1) An OVA-induced mouse models with acute asthma were successfully established.(2) Comparison of the percentage of Treg of splenic CD4+ T lymphocytes: SP group[(12.28±0.73)%, (11.93±0.81)% and (11.70±1.14)%] and AC group[(12.18±1.00)%] were lower than that in the NC group[(13.50±0.39)%] (P<0.05), AP3 group[(10.58±0.65)%] was lower than that in the AC group and AP1 group [(11.91±0.79)%](P<0.05). (3) Comparison of the ratio of Th1/Th2 of splenic CD4+ T lymphocyte: SP1 group[(7.74±1.21)%] was higher than that in the NC group[(5.52±1.06)%](P<0.05), SP2 group[(6.30±0.58)%] was lower than that in the SP1 group(P<0.05), SP3 group[(4.87±0.82)%] was lower than that in the SP2 group(P<0.05); AC group[(3.69±0.47)%] was lower than that in the NC group and SP3 group(P<0.05); AP3 group[(2.92±0.57)%] was lower than that in the AC group(P<0.05). (4) Comparison of the percentage of Th17 of splenic CD4+ T lymphocyte: AP3 group[(1.46±0.39)%] was higher than that in the NC group[(0.89±0.24)%] and the AP2 group[(0.83±0.15)%] (P<0.001). Conclusions PM2.5 can inhibit splenic CD4+ T lymphocyte of acute asthma mice differentiation into Treg and Th1, and promote their differentiation into Th2 and Th17, through which aggravates inflammation reactions in the airway. Key words: PM2.5; Asthma mice; CD4+ T lymphocyte

Prevalence of Toxoplasma gondii in Dogs in Zhanjiang, Southern China.

Toxoplasmosis, caused by Toxoplasma gondii, is a parasitic zoonosis with worldwide distribution. The present study investigated the prevalence of T. gondii in dogs in Zhanjiang city, southern China, using both serological and molecular detection. A total of 364 serum samples and 432 liver tissue samples were collected from the slaughter house between December 2012 and January 2013 and were examined for T. gondii IgG antibody by ELISA and T. gondii DNA by semi-nested PCR based on B1 gene, respectively. The overall seroprevalence of T. gondii IgG antibody was 51.9%, and T. gondii DNA was detected in 37 of 432 (8.6%) liver tissue samples. These positive DNA samples were analyzed by PCR-RFLP at 3'- and 5'-SAG2. Only 8 samples gave the PCR-RFLP data, and they were all classified as type I, which may suggest that the T. gondii isolates from dogs in Zhanjiang city may represent type I or type I variant. This study revealed the high prevalence of T. gondii infection in dogs in Zhanjiang city, southern China. Integrated measures should be taken to prevent and control toxoplasmosis in dogs in this area for public health concern.

Characteristics of Temporal and Spatial Distribution of Water Quality in the Ponds of Lv-Tang-River National Urban Wetland Park, China

Based on the data collected in January, March,July and October in 2013, the characteristics of water quality in temporally and spatially in the ponds of Lv-Tang-River national urban wetland park were investigated. The results show that the main pollutants of Lv-Tang-River wetland are chemical oxygen demand, total nitrogen and ammonia nitrogen. Their average concentrations are worse than the national quality standards for Class V. The characteristics of water quality in spatially are significantly correlated with the plant configuration in the wetland. The water quality in reed pond is the best. Secondly is in natural pond. The worst is in lotus pond. The average of single parameter pollution index (Sj) of reed pond, natural pond and lotus pond is 1.72, 1.82 and 1.96. The water quality in the three ponds belongs to light pollution area. The water quality in July and October is better than that in January and March. In July and October, the water quality belongs to light pollution area and Sj is 1.12 and 1.35 respectively. In January and March, the water quality belongs to moderate pollution area and Sj is 2.17 and 2.71, respectively. In order to improve the water quality in Lv-Tang-River national urban wetland park and protect the ecological environment of Zhanjiang city, the valid measure is to strengthen the management of artificial ponds in winter and spring.

Isolation and Identification of Thermophilic Protease Bacterium 0701 and its Protease Characterization

Soil was collected from Huguangyan of Zhanjiang city and regarded as separate material, It was screened thermophilic protease-producing bacteria though dilution flat, transparent circle and Folin method. Strain 0701 isolated was identificated by its morphological features, physiological and biochemical characteristics and 16s rRNA. This experiment also researched on the genetic stability of enzyme producing, and different temperature, pH influence on proteases activity. 25 high temperature-tolerance protease producing strains were isolated, which accounted for 28.1 % of all the isolated strains. Among them, strain 0701 proteases activity was 247 U/mL and it was far higher than that of proteases for other strains and the most optimum reaction temperature and pH of the proteases were 70oC and pH 7.0, respectively, and retained high enzyme activity within 50-80 oC, pH6.5-9.0. The strain 0703 still had the ability to produce protease after consecutive 4 generation, and was identified as Bacillus subtilis by morphological, physiological-biochemical characteristics and 16s rRNA.

Asian Musk Shrew as a Reservoir of Rat Hepatitis E Virus, China

Asian Musk Shrew as a Reservoir of Rat Hepatitis E Virus, China

High prevalence of rat hepatitis E virus in wild rats in China

Serum samples from a total of 713 wild rats captured in Zhanjiang city in China from December 2011 to September 2012 were investigated for the prevalence of rat hepatitis E virus (HEV) by exploring rat HEV-specific antibodies and RNA. By an ELISA based on recombinant rat HEV-like particles (HEV-LPs), 23.3% (166/713) of the rats were positive for anti-HEV IgG, and 8.3% (59/713) were positive for anti-HEV IgM. The IgG-positive rates in Rattus norvegicus, Bandicota indica, Rattus flavipectus, Rattus rattoides losea, and Rattus rattus hainanus, were 27.8% (64/230), 23.0% (40/174), 19.9% (34/171), 21.5% (26/121), and 11.8% (2/17), while the IgM-positive rates were 8.3% (19/230), 6.9% (12/174), 8.2% (14/171), 10.7% (13/121), and 5.9% (1/17), respectively. The IgG-positive rate of the rats captured in rural areas, 24.1% (84/348), was higher than that in the central area of Zhanjiang city, 15.1% (32/212). The highest IgG-positive rates, as high as 45.3% (39/86), were detected in wild rats trapped in the garbage dump. Twelve of the 59 IgM-positive serum samples were positive for HEV RNA, which was detected in all of the wild rat species except R. rattus hainanus. A phylogenetic analysis of the partial genome of rat HEV ORF1 indicated that all of the 12 HEV strains belong to rat HEV, and no other genotype HEV were detected. The rat HEV from Zhangjiang city could be classified into three separated clusters, suggesting that the infection due to rat HEV with a variety of genome entities occurs extensively among wild rats in China.

Study on the Microstructure of the Pinctada martensii Pearls and Its Significance

The results of a microscopy, SEM-EDS, XRD, FTIR, and Raman spectra study of the nacres of the Pinctada martensii pearls from Zhanjiang city, China shows that they can be classified as the high-quality, medium-quality, and inferior-quality pearls. Aragonite, the main inorganic mineralogy in the nacres, was crystallized and grown up in the compartments formed by the silk and radial organic sheets originating from organic matters secreted by the mantle of mollusks. The crystalline orientations of aragonite tablets were changed from the (002), (012) and (102) crystalline plane nets in the early to the (002) crystalline plane net only in the later. The formation processes of the microstructure of the nacres could be divided into three stages. In the early stage, the precursor particles of aragonite nucleated and grew up fast; then, porous aragonite aggregates consisting of the fine aragonite crystals were formed. In the middle stage, the aragonite crystals directionally grew up to form the aragonite tablets and microlayers. The surface of the aragonite tablets and microlayers are rough and few porous, and the edges of the crystals were serrated. In the last stage, the aragonite tablets in the aragonite microlayer mixed perfectly together to form high-quality aragonite layer whose surface was smooth and perfect.

Site fidelity and association patterns of Indo-Pacific humpback dolphins off the east coast of Zhanjiang, China

This study examined the population of Indo-Pacific humpback dolphins, Sousa chinensis, inhabiting the waters off the east coast of Zhanjiang, China. A total of 116 dolphins were identified during 147 boat-based surveys, completed between June 2005 and June 2007. Abundance estimates indicated that a small population of 268 dolphins (95% CI = 189–413) inhabited this coastal area. The sighting frequencies of identified dolphins varied between one and five when the 2006 and 2007 data were organized into six occasions. Twenty-three percent (27 individuals) of the cataloged dolphins were identified in more than one calendar year. The two animals (ZJ001, ZJ011) with the highest degree of site fidelity were present in the study area for a period of 23 months. The most frequently (15 times) sighted dolphin (ZJ046) was recorded in nine (56%) of the 16 months surveyed. This evidence indicates the interannual site fidelity of S. chinensis to the area off the eastern coast of Zhanjiang City. Range sizes of eight identified individuals calculated by the minimum convex polygon varied from 2.07 to 331.20 km2. Associations between 34 individuals sighted at least three times and more than three times were measured by the half-weight index and SOCPROG program. The majority of these dolphins (80.57%) were not seen together during surveys and the mean association rate between dyads was low at 0.05. Temporal analyses for all the individuals were conducted using a lagged association rate. The results indicated a non-random social structure made by constant companions.

Warfarin resistance in Rattus losea in Guangdong Province, China

Control of rodent populations is performed worldwide with coumarin derivatives, such as warfarin. After widespread use, their effect has been diminished by the rapid spread of resistant rodents. Warfarin resistance in Rattus loseas in Jiangmen and Zhanjiang City, Guangdong Province, was investigated by lethal feeding tests. Twenty-three of 30 R. loseas trapped in Jiangmen City were assayed as warfarin-resistant individuals, whereas only 1 of 30 rodents in Zhanjiang was resistant. These results emphasize the need for thorough resistance monitoring as a basis for adequate control measures to prevent the use of ineffective rodenticides in Jiangmen City. The resistance mechanism mainly involves VKORC1, the molecular target for coumarin drugs. VKORC1 mRNA expression in wild-caught resistant animals showed no difference compared with that in susceptible individuals. Mutation screening of VKORC1 was carried out and an Arg58Gly mutation was identified as the prevailing type in R. loseas from Jiangmen City, which may constitute the genetic basis of anticoagulation resistance in R. losea in this resistance region.