Enhancing Third- and Fifth-Order Nonlinearity via Tunneling in Multiple Quantum Dots.

The nonlinearity of semiconductor quantum dots under the condition of low light levels has many important applications. In this study, linear absorption, self-Kerr nonlinearity, fifth-order nonlinearity and cross-Kerr nonlinearity of multiple quantum dots, which are coupled by multiple tunneling, are investigated by using the probability amplitude method. It is found that the linear and nonlinear properties of multiple quantum dots can be modified by the tunneling intensity and energy splitting of the system. Most importantly, it is possible to realize enhanced self-Kerr nonlinearity, fifth-order nonlinearity and cross-Kerr nonlinearity with low linear absorption by choosing suitable parameters for the multiple quantum dots. These results have many potential applications in nonlinear optics and quantum information devices using semiconductor quantum dots.

Seroprevalence and genetic characterization of Toxoplasma gondii in masked palm civet (Paguma larvata) in Hainan province, tropical China.

In the present study, the seroprevalence, risk factors and genotyping of Toxoplasma gondii in masked palm civet were investigated in tropical China. A total of 500 serum were collected from five administrative farms in tropical China, and assayed for T. gondii antibodies by modified agglutination test (MAT). The brain samples of 20 aborted fetuses were examined by semi-nested-PCR, and positive aborted fetuses (50%) were necropsied to collect the brain tissue for molecular and bioassay examinations. Genomic DNA was extracted from the 29 brain tissues of infected mice and T. gondii B1 gene was amplified using multilocus PCR-RFLP. Overall, 27.6% (95% CI: 23.682-31.518) of the animals was positive for T. gondii antibodies. Ages of masked palm civet was considered as a main risk factor associated with T. gondii infection. 4 DNA samples (13.8%) were positive for the T. gondii B1 gene. Three samples belong to ToxoDB#9, and one belongs to genotype the type II variant (ToxoDB genotype#3). Our results indicated that ToxoDB Genotype#9 has a distribution in masked palm civet that could be potential reservoirs for T. gondii transmission, which may pose a threat to human health.

Seroprevalence and risk factors of Chlamydia psittaci infection in domestic geese Anser domestica, in Hainan province of China.

Chlamydia psittaci, the agent of psittacosis in humans, infects a wide range of bird species. To assess the risk of psittacosis posed by domestic geese in China, the seroprevalence of C. psittaci infection in domestic geese in Hainan province, tropical China was examined using indirect hemagglutination assay (IHA). The overall seroprevalence was estimated at 25.6% (461/1800; 95% CI: 23.6-27.6). The C. psittaci seroprevalence ranged from 19% (95% CI: 14.6-23.4) to 34% (95% CI: 28.6-39.4) among different regions in Hainan province, and the differences were statistically significant (P<0.01). The risk factors significantly associated with C. psittaci seroprevalence were the presence of hygiene conditions, age, gender, and environment of geese in the farms. The results of the present investigation indicated the high seroprevalence of C. psittaci infection in geese in Hainan province, tropical China. Close contact with these geese is associated with a risk of zoonotic transmission of C. psittaci. Public education should be implemented to reduce the risk of avian to human transmission of such a pathogenic agent. To the best of our knowledge, this is the first report documenting the occurrence of C. psittaci seroprevalence in geese in China.

Seroprevalence, risk factors and genotyping of Toxoplasma gondii in domestic geese (Anser domestica) in tropical China.

BACKGROUND: Little information is available about the seroprevalence of Toxoplasma gondii infection in geese (Anser domestica) in China. In the present investigation, the seroprevalence, risk factors and genotyping of T. gondii in geese were investigated in Hainan province, tropical China. FINDINGS: A total of 600 serum samples and 150 brain tissue samples were collected from six administrative regions in tropical China, and assayed for T. gondii antibodies by Indirect Haemagglutination (IHA) test. Genomic DNA was extracted from the 30 brain tissues of seropositive geese and T. gondii B1 gene was amplified using a semi-nested PCR. DNA samples giving positive B1 amplification were then genetically characterized using multi-locus PCR-RFLP. Overall, 17% (95% CI: 14-20) of the animals were positive for T. gondii antibodies. Presence of cats in the household (odds ratio, OR 3), hygiene (OR 2.3) and presence of stray cat around the house (OR 2.3) were considered as main risk factors associated with T. gondii infection. Of 30 DNA samples, three were positive for the T. gondii B1 gene, two showed complete genotyping results. Only one genotype (type II) was identified. CONCLUSIONS: The results of the present survey indicated the presence of T. gondii infection in geese in tropical China. Therefore, it is imperative that improved integrated measures be carried out to prevent and control T. gondii infection in geese in this province. This is the first report documenting the occurrence of T. gondii genotype in geese in China.

Seroprevalence and molecular detection of Mycoplasma ovipneumoniae in goats in tropical China.

In the present study, the seroprevalence and genetic identification of Mycoplasma ovipneumoniae infection in goats were investigated in Hainan Province, tropical China between October 2012 and October 2013. A total of 1,210 serum samples collected from 16 herds in various administrative regions in tropical China were evaluated using indirect hemagglutination assay (IHA). Antibodies to M. ovipneumoniae were tested in (31.7 %, 95 % confidence interval (CI) 29-34.3) 383 of 1,210 serum samples (IHA titer ≥1:16). The M. ovipneumoniae seroprevalence ranged from 26.8 % (95 % CI 20.8-32.9) to 39 % (95 % CI 30.8-47.2) among different regions in tropical China, and the difference was statistically significant (P < 0.01). The seroprevalence of M. ovipneumoniae infection in goats was higher in winter (46.1 %, 95 % CI 39.6-52.5) and spring (33.8 %, 95 % CI 28.3-39.3) than in autumn (27.5 %, 95 % CI 22.6-32.3) and summer (24.7 %, 95 % CI 20.3-29.1), and the difference was statistically significant (P < 0.01). In addition, DNA was extracted from nasal swab; lung samples and the 16S rRNA gene sequences were amplified by polymerase chain reaction (PCR) and then sequenced. Twenty-four of 329 (7.3 %) nasal swab samples and 73 of 280 (26.1 %) pneumonic lung tissues were found to contain M. ovipneumoniae, respectively. The results of the present survey indicate that M. ovipneumoniae infection is highly prevalent in goats in tropical China. This is the first report of the comprehensive survey of M. ovipneumoniae prevalence in goats in China.

Association of thyroglobulin gene variants with carcass and meat quality traits in beef cattle.

Thyroid hormones play an important role in regulating metabolism and can affect homeostasis of fat deposition. The gene encoding thyroglobulin (TG), producing the precursor for thyroid hormones, has been proposed as a positional and functional candidate gene for a QTL with an effect on fat deposition. In the present study, we identified 6 novel SNPs at the 3' flanking region of the TG gene. The SNP marker association analysis indicated that the T354C, G392A, A430G and T433G SNP markers were significantly associated with marbling score (P < 0.05). Animals with the new homozygote genotype had higher marbling score than those with the other genotypes. Otherwise, the linkage disequilibrium analysis indicated that these four SNPs were completely linked (r (2) = 1). Results from this study suggest that TG gene-specific SNP may be a useful marker for meat quality traits in future marker assisted selection programs in beef cattle.

Genetic polymorphisms of the CACNA2D1 gene and their association with carcass and meat quality traits in cattle.

The objective of this study was to identify genetic polymorphisms of the CACNA2D1 gene and to analyze associations between SNPs and carcass and meat quality traits in cattle. Through PCR-RFLP and DNA sequencing methods, a new allelic variant corresponding to the A --> G mutation (aspartic to glycine amino acid replacement) of the bovine CACNA2D1 gene was detected. Two alleles and three genotypes (AA, AG, and GG) were defined. Genetic character indicated that the A526745G locus showed moderate polymorphism and was in Hardy-Weinberg equilibrium. Gene-specific SNP marker association analysis showed that the A526745G mutant was significantly associated with carcass weight, dressing percentage, meat percentage, and backfat thickness. The results add new evidence that CACNA2D1 is an important candidate gene for the selection of carcass and meat quality traits in the cattle industry.

Association analysis of thyroglobulin gene variants with carcass and meat quality traits in beef cattle.

Thyroid hormones play an important role in regulating the metabolism and can affect the homeostasis of fat deposition. The gene encoding thyroglobulin (TG), producing the precursor for thyroid hormones, has been proposed as a positional and functional candidate gene for a QTL with an effect on fat deposition. In the present study, we identified 6 novel SNPs at the 3' flanking region of the TG gene. The SNP marker association analysis indicated that the SNP markers G133C, G156A, C220T and A506C were significantly associated with marbling score (P<0.05, N=271). Animals with the new homozygote genotype had higher marbling scores than those with the other genotypes. Besides, the linkage disequilibrium analysis indicated that these 4 SNPs were completely linked (r2 = 1). Results of this study suggest that the TG-gene-specific SNP may be a useful marker for meat quality traits in future marker-assisted selection programmes in beef cattle.