Comparative analyses of the transcriptome among three development stages of Zeugodacus tau larvae (Diptera: Tephritidae).

Studying differences in transcriptomes across various development stages of insects is necessary to uncover the physiological and molecular mechanism underlying development and metamorphosis. We here present the first transcriptome data generated under Illumina Hiseq platform concerning Zeugodacus tau (Walker) larvae from Nanchang, China. In total, 11,702 genes were identified from 9 transcriptome libraries of three development stages of Z. tau larvae. 7219 differentially expressed genes (DEGs) were screened out from the comparisons between each two development stages of Z. tau larvae, and their roles in development and metabolism were analyzed. Comparative analyses of transcriptome data showed that there are 5333 DEGs between 1-day and 7-day old larvae, consisting of 1609 up-regulated and 3724 down-regulated genes. Expressions of DEGs were more abundant in L7 than in L1 and L3, which might be associated with metamorphosis. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis suggested the enrichment of metabolic process. KOG annotation further confirmed that 20-hydroxyecdysone (20E) pathway related genes Cyp4ac1_1, Cyp4aa1, Cyp313a4_3 were critical for the biosynthesis, transport, and catabolism of secondary metabolites and lipid transport and metabolism. Expression patterns of 8 DEGs were verified using quantitative real-time PCR (RT-qPCR). This study elucidated the DEGs and their roles underlying three development stages of Z. tau larvae, which provided valuable information for further functional genomic research.

Application of computer vision and deep learning models to automatically classify medically important mosquitoes in North Borneo, Malaysia.

Mosquito-borne diseases have emerged in North Borneo in Malaysia due to rapid changes in the forest landscape, and mosquito surveillance is key to understanding disease transmission. However, surveillance programmes involving sampling and taxonomic identification require well-trained personnel, are time-consuming and labour-intensive. In this study, we aim to use a deep leaning model (DL) to develop an application capable of automatically detecting mosquito vectors collected from urban and suburban areas in North Borneo, Malaysia. Specifically, a DL model called MobileNetV2 was developed using a total of 4880 images of Aedes aegypti, Aedes albopictus and Culex quinquefasciatus mosquitoes, which are widely distributed in Malaysia. More importantly, the model was deployed as an application that can be used in the field. The model was fine-tuned with hyperparameters of learning rate 0.0001, 0.0005, 0.001, 0.01 and the performance of the model was tested for accuracy, precision, recall and F1 score. Inference time was also considered during development to assess the feasibility of the model as an app in the real world. The model showed an accuracy of at least 97%, a precision of 96% and a recall of 97% on the test set. When used as an app in the field to detect mosquitoes with the elements of different background environments, the model was able to achieve an accuracy of 76% with an inference time of 47.33 ms. Our result demonstrates the practicality of computer vision and DL in the real world of vector and pest surveillance programmes. In the future, more image data and robust DL architecture can be explored to improve the prediction result.

Comparative multi-tissue analyses identify testis-specific serine/threonine protein kinase (TSSK) genes involved in male fertility in the melon fly Zeugodacus cucurbitae.

BACKGROUND: Zeugodacus cucurbitae is an agricultural pest species with robust reproductive capabilities capable of causing extensive damage. The advent of novel male fertility-related pest control strategies has been an area of active entomological research focused on the sterile insect technique (SIT) strategy. RESULTS: RNA-sequencing analyses were conducted using 16 tissue samples from adult male Z. cucurbitae, leading to the identification of 5338 genes that were differentially expressed between the testes and three other analyzed tissue types. Of these genes, 808 exhibited high levels of testis expression. A quantitative polymerase chain reaction (qPCR) approach was used to validate the expression of ten of these genes selected at random, including ZcTSSK1 and ZcTSSK3, which are testis-specific serine/threonine protein kinase (TSSK) genes. Evaluation via a loss-of-function-based knockdown assay showed that the down-regulation of either of these two genes in males was associated with significantly decreased egg hatching rates. In situ hybridization analyses revealed the expression of both of these transcripts in the transformation zone, and significant decreases in Z. cucurbitae sperm numbers were observed following double-stranded RNA treatment. Together, these results suggested that inhibiting ZcTSSK1 and ZcTSSK3 expression was sufficient to alter male fertility in Z. cucurbitae. CONCLUSION: These transcriptional sequencing results provide a foundation for further efforts to clarify the regulators of Z. cucurbitae male fertility. These preliminary analyses of the functions of ZcTSSK family genes as regulators of spermatogenesis underscore their importance in the processes integral to male fecundity and their potential as targets for pest control efforts centered on the genetic manipulation of males. © 2023 Society of Chemical Industry.

Public Awareness, Perception, and Knowledge of Bed Bug Infestation Prevalence in Iraq.

Background: Bed bugs are blood-feeding insects and are an important urban pest. Bed bugs are nocturnal insects and hide in cracks in walls and beds during the day. The study aims to: (1) determine the bed bugs species that infest Iraq, their infestation source, and their distribution; (2) determine the level of awareness and concern regarding bed bugs among the Iraqi community. Methods: Between 2020 and 2021, a survey of bed bug infestation dynamics was conducted in 18 infested sites located in major cities across eight governorates. The 23-item online survey was distributed over social media to Iraqi citizens between June and July 2022 to survey on their familiarity with bed bug habitat, medical significance, transmission, prevention, control measures, and concerns. Results: There were a total of 1104 bed bugs collected. Based on the morphological characteristics, bed bugs collected from eight Iraqi governorates are identified as Cimex hemipterus. Besides, a high rate of bed bug infestation was observed in workers' dormitories. The online questionnaire was answered by 1843 respondents and based on the feedback, most respondents (55.3%) have no awareness of bed bug infestations, while around 43.8% are somewhat concerned about bed bug infestations in Iraq. Conclusion: Only tropical bed bugs, C. hemipterus were found in all sampled sites. Bed bug infestations are mainly caused by migrant workers and the reuse of second-hand furniture and clothing. The results suggest that the Iraqi government should organize more proper demonstrations on bed bug awareness for the public.

Expression and Role of Vitellogenin Genes in Ovarian Development of Zeugodacus cucurbitae.

Vitellogenin (Vg) genes encode the major egg yolk protein precursor in arthropods. In this study, four Vgs were identified in Zeugodacus cucurbitae (Coquillett). Sequence analysis showed that four ZcVgs had the conserved Vg domain. Phylogenetic analysis indicated that four ZcVgs were homologous to the Vgs of Tephritidae insects. The temporal and spatial expression patterns of ZcVgs were analyzed by quantitative real-time polymerase chain reaction (RT-qPCR), and the four ZcVgs showed high expression levels in female adults, especially in the fat body. The expression of ZcVg1 and ZcVg3 was down-regulated by a low dosage (0.5 µg) of 20-hydroxyecdysone (20E), and ZcVg2, ZcVg3, and ZcVg4 were up-regulated by a high dosage (1.0 and 2.0 µg) of 20E. The expression of ZcVg1 and ZcVg2 was up-regulated by 5 µg of juvenile hormone (JH), while all of the ZcVgs were down-regulated by a low and high dosage of JH. Expression of ZcVgs was down-regulated after 24 h of starvation and recovered to normal after nutritional supplementation. After micro-injection of the gene-specific double-stranded RNA, the ZcVgs' expression was significantly suppressed, and ovarian development was delayed in Z. cucurbitae females. The results indicate that RNA interference of reproduction-related genes is a potential pest control method that works by manipulating female fertility.

Identification and Expression Characterization of ATP-Binding Cassette (ABC) Transporter Genes in Melon Fly.

The ATP-binding cassette (ABC) transporter is a protein superfamily that transports specific substrate molecules across lipid membranes in all living species. In insects, ABC transporter is one of the major transmembrane protein families involved in the development of xenobiotic resistance. Here, we report 49 ABC transporter genes divided into eight subfamilies (ABCA-ABCH), including seven ABCAs, seven ABCBs, 10 ABCCs, two ABCDs, one ABCE, three ABCFs, 16 ABCGs, and three ABCHs according to phylogenetic analysis in Zeugodacus cucurbitae, a highly destructive insect pest of cucurbitaceous and other related crops. The expressions level of 49 ABC transporters throughout various developmental stages and within different tissues were evaluated by quantitative transcriptomic analysis, and their expressions in response to three different insecticides were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). These ABC transporter genes were widely expressed at developmental stages but most highly expressed in tissues of the midgut, fat body and Malpighian tube. When challenged by exposure to three insecticides, abamectin, ß-cypermethrin, and dinotefuran, the expressions of ZcABCB7 and ZcABCC2 were significantly up-regulated. ZcABCB1, ZcABCB6, ZcABCB7, ZcABCC2, ZcABCC3, ZcABCC4, ZcABCC5, and ZcABCC7 were significantly up-regulated in the fat body at 24 h after ß-cypermethrin exposure. These data suggest that ZcABCB7 and ZcABCC2 might play key roles in xenobiotic metabolism in Z. cucurbitae. Collectively, these data provide a foundation for further analysis of ABCs in Z. cucurbitae.

Sex-Specific Influence of the SCARB1 Rs5888 SNP on the Serum Lipid Response to Atorvastatin in Patients with Acute Coronary Syndrome Undergoing Percutaneous Coronary Intervention.

BACKGROUND: Epidemiological studies have shown that there are sex differences in blood lipid levels and lipid responses to statins. Previous studies have shown that the rs5888 single nucleotide polymorphism (SNP) in the scavenger receptor class B type 1 (SCARB1) gene is associated with serum lipid levels in a sex-specific manner. The present study was undertaken to detect the sex-specific influence of the SCARB1 rs5888 SNP on the serum lipid response to atorvastatin in patients with acute coronary syndrome (ACS) undergoing percutaneous coronary intervention (PCI). METHODS: A total of 158 unrelated ACS patients (108 males, 50 females) were enrolled, and all patients received atorvastatin 20 mg/daily after PCI. Genotyping of the rs5888 SNP was performed by polymerase chain reaction and direct sequencing. Serum lipid profiles were determined before treatment and after an average follow-up time of one year. RESULTS: The baseline serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and apolipoprotein (Apo)AI levels were higher in females than in males (P<0.05). After treatment with atorvastatin, serum TC, LDL-C, and ApoB were decreased, and ApoAI was increased (P<0.05). The effects of atorvastatin on serum lipid levels were different between males and females, and females had greater decreases in TC, LDL-C and ApoB levels than males (P<0.05). The genotypic frequencies of the rs5888 SNP were not different between males and females. The atorvastatin response was not associated with the rs5888 SNP in males (P > 0.05). Nonetheless, in female individuals carrying the rs5888 T-allele, we observed a greater reduction in TC, LDL-C, and ApoB levels after the use of 20 mg/day atorvastatin (P<0.05). CONCLUSION: This study indicates that the SCARB1 rs5888 T-allele was associated with a greater reduction in serum TC, LDL-C, and ApoB after atorvastatin treatment in female patients with ACS undergoing PCI.

Genome-wide analysis of long non-coding RNAs in adult tissues of the melon fly, Zeugodacus cucurbitae (Coquillett).

BACKGROUND: Long non-coding RNAs (lncRNAs) are involved in many fundamental biological processes, such as transcription regulation, protein degradation, and cell differentiation. Information on lncRNA in the melon fly, Zeugodacus cucurbitae (Coquillett) is currently limited. RESULTS: We constructed 24 RNA-seq libraries from eight tissues (midgut, Malpighian tubules, fat body, ovary, and testis) of Z. cucurbitae adults. A total of 3124 lncRNA transcripts were identified. Among those, 1464 were lincRNAs, 1037 were intronic lncRNAs, 301 were anti-sense lncRNAs, and 322 were sense lncRNAs. The majority of lncRNAs contained two exons and one isoform. Differentially expressed lncRNAs were analyzed between tissues, and Malpighian tubules versus testis had the largest number. Some lncRNAs exhibited strong tissue specificity. Specifically expressed lncRNAs were identified and filtered in tissues of female and male Z. cucurbitae based on their expression levels. Four midgut-specific lncRNAs were validated by quantitative real-time polymerase chain reaction (RT-qPCR), and the data were consistent with RNA-seq data. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses of targets of midgut-specific lncRNAs indicated an enrichment of the metabolic process. CONCLUSIONS: This was the first systematic identification of lncRNA in the melon fly. Expressions of lncRNAs in multiple adult tissues were evaluated by quantitative transcriptomic analysis. These qualitative and quantitative analyses of lncRNAs, especially the tissue-specific lncRNAs in Z. cucurbitae, provide useful data for further functional studies.

[Influence of Secondary Organic Coating on Hygroscopicity of a Sodium Chloride Core: Based on Mircro-scale Single Particle Analysis].

The hygroscopicity of atmospheric particulate matter can determine its optical behaviors, cloud condensation nuclei activity, and heterogeneous chemical reaction on the surface. However, the effect of secondary organic matter on the hygroscopicity of inorganic salts is still rarely studied. In this study, a 2 L gas-phase flow tube was used to stimulate the oxidation process of α-pinene. NaCl particles at the end of the flow tube served as seeds to absorb the product of α-pinene oxidation. The absorption times were 11, 15, and 20 h. Transmission electron microscopy results show that this system could produce particles with typical core-shell structure, and that the thickness of the organic shell would be thicker with longer collection time. Results from individual particle hygroscopic systems indicate that the organic shell can affect the deliquescent point of NaCl (pure NaCl deliquesces at 77%):for 11 h collection time, the NaCl core began to deliquesce at 75.5% relative humidity, and completely deliquesced at 78%; for 15 h collection time, the deliquescent range of the NaCl core was 75%-78.5%; and the deliquescent range was 76%-83% for the NaCl core with 20 h collection time. Furthermore, the organic shell could affect the hygroscopic growth of the NaCl core:the growth factor of the NaCl core with 11 h, 15 h, and 20 h collection time was 2.5, 2.3, and 1.8, respectively. These results indicate that:① the secondary organic shell could cause water absorption of the NaCl core in advance:② the organic shell could postpone the completely deliquescent point of the NaCl core, and this effect is more obvious with a thicker organic shell; ③ the organic shell could restrain the hygroscopic growth factor of the NaCl core. This study suggests that it is necessary to consider the influence of secondary organic matter on inorganic salts when studying the hygroscopic properties of atmospheric particles in climate models and field observations.

Genome-wide gene expression profiling of the melon fly, Zeugodacus cucurbitae, during thirteen life stages.

The melon fly, Zeugodacus cucurbitae (Coquillett), is an important destructive pest worldwide. Functional studies of the genes associated with development and reproduction during different life stages are limited in Z. cucurbitae. There have yet to be comprehensive transcriptomic resources for genetic and functional genomic studies to identify the molecular mechanisms related to its development and reproduction. In this study, we comprehensively sequenced the transcriptomes of four different developmental stages: egg, larva, pupa, and adults. Using the Illumina RNA-Seq technology, we constructed 52 libraries from 13 stages with four biological replicates in each and generated 435.61 Gb clean reads. We comprehensively characterized the transcriptomes with high-coverage mapping to the reference genome. A total of 13,760 genes were mapped to the reference genome, and another 4481 genes were characterized as new genes. Finally, 14,931 genes (81.85%) were functionally annotated against six annotation databases. This study provides the first comprehensive transcriptome data of all developmental stages of Z. cucurbitae, and will serve as a valuable resource for future genetic and functional studies.

Gene expression profiling of ovary identified eggshell proteins regulated by 20-hydroxyecdysone in Bactrocera dorsalis.

The oriental fruit fly, Bactrocera dorsalis, is one of the most destructive pests worldwide. The frequent use of chemical insecticides has led B. dorsalis to develop resistance to many insecticides in recent decades. New high-throughput-sequenced transcriptomes, as well as genomes, have revealed a large number of reference genes for functional target identification. Here, we performed digital gene expression profiling of ovary and testis of B. dorsalis adults. Various genes were identified to be highly expressed in B. dorsalis ovary. The genes encoding components of eggshell, vitelline membrane proteins (Vmps) and chorion-related proteins, were identified to be tissue-specifically expressed in ovary. Five cytochrome P450 genes were also identified to be highly expressed in ovary. Three of them were ecdysone synthesis pathway genes indicating the ovary as a potential synthesis site of female. The up-regulated expression of Vmps by exogenous 20-hydroxyecdysone implied the hormonal regulation of eggshell formation during ovarian development. Many other genes with potential functions in ovarian development were also identified, including vitellogenin receptor, insulin receptor, NASP protein, and odorant binding protein. These findings should promote our understanding of the regulation of vitellogenesis and eggshell formation and enable exploration of potentially novel pest control targets.

Association between the PPP1R3B polymorphisms and serum lipid traits, the risk of coronary artery disease and ischemic stroke in a southern Chinese Han population.

BACKGROUND: Little is known about the association of the protein phosphatase 1 regulatory subunit 3B gene (PPP1R3B) single nucleotide polymorphisms (SNPs) and serum lipid levels, the risk of coronary artery disease (CAD) and ischemic stroke (IS) in the Chinese populations. This study detected such association in a Southern Chinese Han population. METHODS: Genotypes of 4 novel PPP1R3B SNPs (rs12785, rs330910, rs330915 and rs9949) in 1704 Han Chinese (CAD, 556; IS, 531 and control, 617) were determined by the Snapshot technology. RESULTS: The rs12785A and rs9949A allele frequency was higher in both CAD/IS patients than in controls. The rs330910T and rs330915T allele frequency was also higher in CAD patients than in controls. The rs330910T allele carriers in controls had lower serum low-density lipoprotein cholesterol (LDL-C) levels than the rs330910T allele non-carriers (P < 0.0014). The rs12785A, rs9949A and rs330910T allele carriers were associated with an increased risk of CAD (P = 0.008-0.004). There was strong linkage disequilibrium among the 4 SNPs in the controls and CAD/IS patients. The T-A-A-G haplotype was associated with a decreased risk of CAD and IS, whereas the A-A-T-A haplotype was associated with an increased risk for IS. Haplotype-environment interactions on the risk of CAD and IS were also observed. CONCLUSIONS: Several PPP1R3B polymorphisms were associated with serum LDL-C levels, the risk of CAD and IS in the Southern Chinese Han population. But these findings still need to be confirmed in the other populations with larger sample sizes.

DOCK7-ANGPTL3 SNPs and their haplotypes with serum lipid levels and the risk of coronary artery disease and ischemic stroke.

BACKGROUND: Little is known about the association of the dedicator of cytokinesis 7 (DOCK7 rs1748195) and angiopoietin like 3 (ANGPTL3 rs12563308) single nucleotide polymorphisms (SNPs) and their haplotypes with serum lipid levels and the risk of coronary artery disease (CAD) and ischemic stroke (IS) in the Chinese populations. This study aimed to detect such association in a Southern Chinese Han population. METHODS: This study included 1728 subjects (CAD, 568; IS, 539; and controls, 621). Genotypes of the two SNPs were determined by the Snapshot technology. RESULTS: The genotypic and allelic frequencies of the rs1748195 SNP were different between CAD patients and controls (P < 0.05 for each), the rs1748195G allele frequency was higher in CAD patients than in controls (27.6% vs. 23.6%, P = 0.024). The genotypic frequencies of the rs12563308 SNP were also different between CAD patients and controls (P = 0.021). The rs1748195 SNP was associated with an increased risk of CAD after controlling for potential confounders and Bonferroni correction (P < 0.025 considered statistically significant; Recessive: OR = 1.79, 95% CI = 1.04-3.06, P = 0.017; Log-additive: OR = 1.27, 95% CI = 1.02-1.57, P = 0.014), whereas the rs12563308 SNP was associated with a decreased risk of CAD (Dominant: OR = 0.69, 95% CI = 0.45-0.94, P = 0.011; Log-additive: OR = 0.73, 95% CI = 0.49-0.89, P = 0.009). The rs1748195 SNP was also associated with an increased risk of severity to coronary artery atherosclerosis (Dominant: OR = 1.45, 95% CI = 1.07-2.11, P = 0.017; Log-additive: OR = 1.35, 95% CI = 1.09-1.82, P = 0.013). The interactions of SNP-environment on serum lipid levels and the risk of severity to coronary artery atherosclerosis, CAD and IS were noted. The rs1748195G-rs12563308T haplotype was associated with an increased angiographic severity to coronary artery atherosclerosis (OR = 1.46, 95% CI = 1.05-2.03), and the risk of CAD (OR = 1.37, 95% CI = 1.08-1.74). The interactions of haplotype-hypertension on the risk of CAD and haplotype-drinking on the risk of CAD/IS were observed. CONCLUSIONS: These results suggest that the DOCK-ANGPTL3 SNPs and their haplotypes were associated with the angiographic severity to coronary artery atherosclerosis and the risk of CAD and IS in the Southern Chinese Han population.

Association of the TTC39B rs581080 SNP and serum lipid levels and the risk of coronary artery disease and ischemic stroke.

The tetratricopeptide repeat domain protein 39B gene (TTC39B) single nucleotide polymorphism (SNP) of rs581080 has been associated with serum high-density lipoprotein cholesterol (HDL-C) levels. However, little is known about such association in the Chinese populations. The present study was performed to assess the association between the TTC39B rs581080 SNP and serum lipid levels and the risk of coronary artery disease (CAD) and ischemic stroke (IS) in the Guangxi Han population. Genotypes of the TTC39B rs581080 SNP in 1741 unrelated subjects (CAD, 578; IS, 537; and healthy controls; 624) were determined by the Snapshot Technology. The genotypic and allelic frequencies of the TTC39B rs581080 SNP were different between the CAD/IS patients and controls (P < 0.01 for all). The CG/GG genotypes and G allele were associated with an increased risk of CAD (P = 0.001 for CG/GG vs. CC, P = 0.003 for G vs. C) and IS (P = 0.002 for CG/GG vs. CC; P = 0.004 for G vs. C). The CG/GG genotypes in the healthy controls, but not in CAD or IS patients, were also associated with a decreased serum HDL-C concentration. These results suggest that the TTC39B rs581080 SNP is associated with the risk of CAD and IS in our study population. It is likely to increase the risk of CAD and IS by reducing serum HDL-C levels.

Association of RBM5 rs2013208 SNP with serum lipid levels in two Chinese ethnic groups.

The RNA binding motif protein 5 gene (RBM5) rs2013208 single nucleotide polymorphism (SNP) has been associated with high-density lipoprotein cholesterol (HDL-C) levels in a previous genome-wide association study, but little is known about such association of the RBM5 rs2013208 SNP and serum lipid profiles in the Chinese populations. The present study was to detect the association of the RBM5 rs2013208 SNP and several environmental factors with serum lipid levels in the Jing and Han populations. Genotyping of the RBM5 rs2013208 SNP in 635 subjects of Jing and 648 participants of Han peoples was performed by polymerase chain reaction and restriction fragment length polymorphism, and then confirmed by direct sequencing. There were no significant differences in the genotypic and allelic frequencies of the RBM5 rs2013208 SNP between the two ethnic groups or between males and females. The RBM5 rs2013208G allele carriers had lower serum HDL-C levels in both Jing and Han than the G allele non-carriers. The G allele carriers in Jing had higher serum total cholesterol (TC) levels and higher apolipoprotein (Apo) A1/ApoB ratio than the G allele non-carriers (P < 0.05). Subgroup analysis according to sex showed that the G allele carriers had lower serum HDL-C levels in both Jing and Han females but not in males (P < 0.05). The G allele carriers had higher TC levels in Jing females but not in Jing males, and lower ApoA1/ApoB ratio in Jing males but not in Jing females. Serum lipid parameters were also correlated with several environmental factors in the Jing and Han populations, or in males and females in both ethnic groups. The association of the RBM5 rs2013208 SNP and serum lipid levels is different between the Jing and Han populations. These associations might have an ethnic- and/or sex-specificity.

[Physico-chemical Characteristics of Individual Aerosol Particles in Marine Atmosphere on South Hemisphere].

During the 29th Chinese National Antarctic Research Expedition (CHIANRE), individual particle samples were collected from South China to Antarctic during November 2012 to April 2013. A transmission electron microscopy with energy-dispersive X-ray spectrometry (TEM-EDS) was employed to analyze the morphology, mixing state, composition, and relative abundances of individual aerosol particles. Atmospheric particles were classified into four types:sea salt, mineral, S-rich and C-rich. Sea salt aerosols (SSA) were dominant in the marine particles from South China to Antarctic, and they were further divided into three sub-types:fresh SSA, partially aged SSA, and fully aged SSA. Partially and fully aged SSA accounted for 86% of total SSA number. Interestingly, surface of partially aged SSA and fully aged SSA contained abundant rod-like Na2SO4. Mineral dust particles increased in the coastal areas which were influenced by continental air. In addition, we found that S-rich particles were abundant at two sampling sites (the middle eastern of Indian Ocean and Antarctic inland). The back trajectories of air masses indicated that these S-rich particles were mainly formed via the oxidation of dimethyl sulfide (DMS) emitted from the marine phytoplanktons. Our study suggests that the SSA aging process in the South Hemisphere atmosphere was controlled by the DMS which is different from the SSA aging under the influence of anthropogenic pollutants in the North Hemisphere.

A New Feature Extraction Method of Near-Infrared Spectra Based on the Addition of Historical Data.

In traditional qualitative analysis of near-infrared (NIR) spectra, the stability of recognition models is decreased when new varieties of samples are added into the model. In order to improve the robustness of the model, a new feature extraction method based on the addition of historical data was put forward. The NIR training samples will be collected first, after that the historical data of the same species is added to constitute a larger and richer dataset. Then, the pretreated data of these training samples is projected to the feature space, which is constructed by feature extraction using partial least squares (PLS) based on the above dataset. Subsequently, orthogonal linear discriminant analysis (OLDA) is employed to extract features of the projected data. 18 varieties of corn seeds were taken as study subject, the comparative experiments with and without historical data are implemented respectively, and then the biomimetic pattern recognition (BPR) method is applied to verify the efficiency of the method proposed. The results suggest that the method adopted can improve the robustness of recognition model more effectively compared with the method without historical data. It maintains the high correct recognition ratios when new varieties are added into the model. Besides that, the recognition effect on test sets of the different days remains the same basically in the condition of same PLS dimensions. Therefore, the dimension of feature extraction can be set to some fixed values in recognition software. In this way, it can keep out of the trouble of manually modifying the optimal PLS parameter in recognition software if new varieties need to be added into the model. The experiment results of the thesis manifested the effectiveness of the proposed method.

[Analysis of the stability and adaptability of near infrared spectra qualitative analysis model].

The stability and adaptability of model of near infrared spectra qualitative analysis were studied. Method of separate modeling can significantly improve the stability and adaptability of model; but its ability of improving adaptability of model is limited. Method of joint modeling can not only improve the adaptability of the model, but also the stability of model, at the same time, compared to separate modeling, the method can shorten the modeling time, reduce the modeling workload; extend the term of validity of model, and improve the modeling efficiency. The experiment of model adaptability shows that, the correct recognition rate of separate modeling method is relatively low, which can not meet the requirements of application, and joint modeling method can reach the correct recognition rate of 90%, and significantly enhances the recognition effect. The experiment of model stability shows that, the identification results of model by joint modeling are better than the model by separate modeling, and has good application value.

[Study on spectral calibration of discrimination of corn variety using near-infrared spectra based on DS algorithm].

From the perspective of calibration, the present paper studies the model stability problem in qualitative analysis of NIR. Aiming at the issue of model failure caused by different data acquisition time, 13 varieties of corn were used as experimental material, and learning from the idea of model calibration transfer between the two instruments in quantitative analysis of NIR, the DS (direct standardization) algorithm was used to calibrate the spectra acquired at different times with the same instrument, that made the varieties identification model established one time able to be applied to identify the test data at different acquisition time. First, transfer set was selected from the master spectrum set by Kennard/Stone algorithm, the corresponding number spectrums in slave spectrum set were selected, and then DS algorithm was applied to transfer set to calculate the transformation function between the two sets of data. Finally, the remaining slave spectrums were transformed so that they could apply to the model. This study does some experiment to discuss the impact of the number of transfer set and the location of calibration on the calibration results. Respectively, the experiment results were analyzed from two aspects, one is the correct discrimination rate in qualitative analysis, and the other is the distribution distance between master spectrums and slave spectrums before and after calibration. The experiment results indicate that this approach is effective to solve the spectra drift produced by sampling over time, can bring higher recognition rate on different sampling time test sets, also improves the robustness and application scope of the identification model, and the experiment results also indicate that the best result can be obtained with calibration locating after feature extraction.

A possible mechanism in DHEA-mediated protection against osteoarthritis.

Dehydroepiandrosterone (DHEA) and its ester form, DHEA-S, are the most abundant steroids in human plasma. Our previous studies showed that DHEA protects against osteoarthritis (OA). The aim of this paper was to explore the possible mechanisms that underlie DHEA-mediated protection against OA. We tested the expression of ß-catenin, it was increased significantly in OA. Rabbit cartilage was treated with various concentrations of DHEA in both IL-1ß-induced rabbit chondrocytes and in rabbit cartilage from the anterior cruciate ligament transaction-induced OA model. We found DHEA decreased the expression of ß-catenin. Then we further activated Wnt/ß-catenin signaling by ß-catenin transfection and inactivated it by the inhibitor Dickkopf1 in chondrocytes to reveal its role in the pathogenesis of OA. It turns out the protective effect of DHEA was significantly decreased when Wnt/ß-catenin signaling was activated, while inactivating Wnt/ß-catenin signaling enhanced the effects of DHEA. Therefore, we hypothesize that DHEA probably exerted its chondroprotective effect by regulating Wnt/ß-catenin signaling. Our findings demonstrate the critical role of Wnt/ß-catenin signaling in DHEA-mediated protection against OA.