[Integrin α5 promotes the proliferation, invasion and adhesion of gastric cancer by regulating the FAK/Src/Rac1 signaling pathway].

Objective: To elucidate the biological role and potential mechanism of integrin α5 (ITGA5) in gastric cancer (GC). Methods: From January 2019 to December 2020, 35 pairs of GC tissue [21 males and 14 females, aged (53.8±5.4) years] and matched adjacent tissue samples were collected from GC patients who underwent surgical resection in Zhejiang Provincial People's Hospital. GC and normal gastric mucosa cells were purchased from Beijing Biobw Biotech Company. Quantitative real-time PCR (qRT-PCR), immunohistochemistry, Western blotting were performed to detect the mRNA and protein expression levels of ITGA5, cell adhesion-related genes (pFAK, pSrc, aRac1) in GC cells. Cell Counting Kit-8 (CCK-8), Transwell invasion, wound healing and cell adhesion assays were conducted for GC cell phenotype detection. Results: ITGA5 was highly expressed in GC compared with normal gastric mucosa cells (relative expression increased from 1.00±0.26 to 1.23±0.27,P<0.05). In addition, ITGA5 overexpression promoted the cell proliferation [from (1.14±0.14) OD to (1.61±0.14) OD], migration ability [from (20.3±2.3)% to (56.4±6.1)%], invasion ability (from 144.0±4.6 to 216.7±6.6), and adhesion ability of matrix protein (from 99.0±8.5 to 152.0±12.3) through FAK/Src/Rac1 signaling pathway in GC.(all P<0.05) Conclusions: ITGA5 acts as a cancer-promoting factor in GC. The current study provides theoretical evidence for probing the novel molecular targets for the treatment of GC.

Environmental Exposure-Associated Human Health Risk of Dioxin Compounds in the Vicinity of a Municipal Solid Waste Incinerator in Shanghai, China.

In order to assess environmental exposure-associated human health risk of dioxin compounds for the population in the vicinity of a municipal solid waste incinerator (MSWI) in Shanghai, the atmospheric samples (n = 24) and soils samples (n = 96) were collected and analyzed to obtain the concentration level, pollution characteristics and seasonal changes of dioxin compounds in environmental medias. The toxicity equivalent concentration range of 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) was 30.9-409 fg WHO-TEQ·m-3 in atmosphere and 0.362-8.55 ng WHO-TEQ·kg-1 in soil. The non-carcinogenic health risk and carcinogenic health risk from PCDD/Fs environmental exposure of people living in the vicinity of the MSWI in Shanghai were all within the allowable range of the US Environmental Protection Agency, which implied that the MSWI in Shanghai did not produce additional risk for the population living in its vicinity.

[Diagnosis and treatment of gastric cancer with immediate double primary carcinoma].

Objective: To investigate the clinical characteristics, treatment and prognosis of gastric cancer complicated with immediate double primary cancer. Methods: The clinical data of patients who met the diagnostic criteria of gastric cancer with immediate double primary cancer from January 2016 to June 2019 were analyzed retrospectively. Results: There were 29 cases of gastric cancer with immediate double primary carcinoma, accounting for 1.7% of the 1 741 patients with gastric cancer in the same period. Of these, 17 (58.6%) were more than 70 years of age. 25 cases (86.2%) were male. The postoperative pathological staging was mainly for early gastric cancer (63.2%). Colorectal cancer accounted for 8 cases (27.6%), followed by esophageal cancer in 7 cases (24.1%). The others included 6 cases of lung cancer (20.7%), 2 cases of pancreatic cancer (6.9%), 2 cases of prostate cancer (6.9%), 1 case of non-Hodgkin's lymphoma (3.4%), 1 case of ampullary tumor (3.4%), 1 case of bile duct carcinoma (3.4%) and 1 case of laryngeal carcinoma (3.4%). The prognosis of the surgical treatment group was significantly better than that of the non-surgical treatment group (median survival time: 21.0 months vs 13.0 months, P=0.014). Conclusion: Gastric cancer complicated with immediate double primary cancer mostly occurs in elderly men and early gastric cancer patients. In the complicated tumor, colorectal cancer is the main cause, so we should pay attention to the screening of digestive system. Radical surgery should be performed as far as possible for each primary tumor.

Optical property study of FePt-C nanocomposite thin film for heat-assisted magnetic recording.

Optical properties of the FePt-C nanocomposite thin film that was synthesized by sputtering with MgO/NiTa underlayer on glass substrate have been determined by an approach combining spectroscopic ellipsometry and transmission over the wavelength range of 380 - 1700 nm. It was observed that the refractive index is larger than the extinction coefficient, indicating that free electron absorption is not the dominant optical transition in the FePt-C thin film. Compared with FePt thin film, the FePt-C thin film has smaller optical constants, which lead to better optical performance including smaller optical spot on recording media and higher transducer efficiency for heat assisted magnetic recording.

Nanostructured SmCo5 thin films with perpendicular anisotropy formed in a wide range of Sm-Co compositions.

In this work, we prepared SmCo5 thin films with (0001) texture exhibiting perpendicular anisotropy in a wide range of Sm(x)Co(100-x) compositions (x = 13.2 approximately 37.0) on Cu/Ta underlayers. At a composition of Sm16.7Co83.3 (SmCo5), the SmCo5 film exhibits a maximum perpendicular coercivity of 18.2 kOe, which is attributed to a good crystallinity and an excellent (000l) texture. The SmCo5 (000l) peaks are shifted to smaller angles compared to the standard powder sample which indicates the formation of a SmCoCu alloy through Cu diffusion. The EDX result for this sample gives a composition of SmCo3Cu2.1 which confirms Cu diffusion into the SmCo5 layer. TEM image shows that SmCo5 film is well crystallized with a grain size of 50 nm.

Interlayer exchange coupling effect of L1(0) CoPt based exchange coupled composite media.

In this work, effects of exchange coupling of soft magnetic layer on switching field and magnetization reversal behaviour of CoPt-SiO2(soft)/CoPt-SiO2(hard) exchange coupled media were investigated. With increasing the thickness of the soft layer, both the coercivity and magnetization squareness of composite media decreased. Soft layer thickness 4 nm and below was more effective to significantly reduce the switching field than that above 4 nm. More incoherent switching behavior was observed with increasing soft layer thickness.

NiW/Ru underlayer for CoPt-SiO2 granular perpendicular recording media.

This paper presented the usage of the NiW/Ru underlayer to replace the single Ru underlayer for promoting CoPt hcp (0002) texture. Fcc (111) textured NiW film was used to induce the Ru hcp (0002) texture. It was found that the utilization of the (111) textured NiW alloying layer promoted the formation of Ru(0002) texture, enhanced the magnetic grain isolation and generated the uniform grains with gain size less than 10 nm in CoPt-SiO2 recording layer. The out-of-plane coercivity was also enhanced with the growth of 10 nm NiW underlayer below the Ru layer.

FeTaC magnetic soft underlayer for L1(0) FePt based perpendicular recording media.

FeTaC magnetic soft underlayer under elevated temperature process conditions for L1(0) FePt based perpendicular recording media has been investigated. After annealing FeTaC for 40 min at 350 degrees C, saturation moment increases to 750 emu/cm3 and, coercivity and remanent moment reduce to 2.3 Oe and 166 emu/cm3 respectively. The microstructure of FeTaC annealed at 350 degrees C for 40 min composes of Fe nanocrystals with random orientations immersed in an amorphous matrix. FeTaC surface roughness due to elevated temperature process is reduced by 100 W RF plasma etching and CrRu with (200) orientation is developed. It is found that changing elemental composition due to C diffusion into the CrRu layer and RF preferential etching over Fe, Ta and C has the influence on the magnetic properties of FeTaC.

Nanogranular L1(0) FePt-C-Ta2O5 composite media for perpendicular recording applications.

In this report, the effect of simultaneously adding two dopants (C and Ta2O5) in FePt was investigated. (Fe55Pt45)79C21-(x vol%) Ta2O5 films (where x = 0% to 20%) were prepared using both low and high power magnetron sputtering on MgO (2 nm)/CrRu (30 nm) underlayers with in-situ heating at 350 degrees C. Films deposited at low power showed a decrease in exchange coupling with increasing Ta2O5 content. Out-of-plane coercivity of 7.2 kOe was observed even with up to 20 vol% Ta2O5. X-Ray diffraction spectra showed presence of FePt(001) texture for all compositions of Ta2O5 ranging from 0 to 20 vol% suggesting that the perpendicular anisotropy was maintained even with up to 20 vol% of dopant content. Films deposited at high power showed a different behavior with an initial increase in out-of-plane coercivity to 8.2 kOe and a reduction in exchange coupling with loop slope parameter (alpha) approaching a fully decoupled value of 1. Further increase in doping content led to deterioration in the out-of-plane coercivity, as well as an increase in the exchange coupling.

[Discussion on early warning, prevention and control of emerging infectious diseases from a macroscopic perspective based on big data and effective distance model: enlightenment of COVID-19 epidemic data in China].

Objective: To provide a system for warning, preventing and controlling emerging infectious diseases from a macroscopic perspective, using the COVID-19 epidemic data and effective distance model. Methods: The dates of hospitalization/isolation treatment of the first confirmed cases of COVID-19 and the cumulative numbers of confirmed cases in different provinces in China reported as of 23 February, 2020 were collected. The Location Based Service (LBS) big data platform of "Baidu Migration" was employed to obtain the data of the proportion of the floating population from Wuhan to all parts of the country. Effective distance models and linear regression models were established to analyze the relationship between the effective distance and the arrival time of the epidemic as well as the number of cumulative confirmed cases at provincial and municipal levels. Results: The arrival time of the epidemic and the cumulative number of confirmed cases of COVID-19 had significant linear relationship at both provincial and municipal levels in China, and the regression coefficients of each linear model were significant (P<0.001). At the provincial level, the effective distance could explain about 71% of the variation of the model with arrival time along with around 90% of the variation for the model in the cumulative confirmed case magnitude; at the municipal level, the effective distance could explain about 66% of the variation for the model in arrival time, and about 85% of the variation of the model with the cumulative confirmed case magnitude. Conclusions: The fitting degree of the models are good. The LBS big data and effective distance model can be used to estimate the track, time and extent of epidemic spread to provide useful reference for early warning, prevention and control of emerging infectious diseases.

Let-7 participates in the regulation of inflammatory response in spinal cord injury through PI3K/Akt signaling pathway.

OBJECTIVE: To study the potential mechanism of let-7 in participating in the regulation of inflammatory response in spinal cord injury (SCI). MATERIALS AND METHODS: A total of 40 male Sprague-Dawley rats were randomly divided into four groups: group A (Sham, n=10), group B (SCI+NC, n=10), group C (SCI+antagomir, n=10), and group D (SCI+mimics, n=10). The SCI model was established via operation in all groups. After successful modeling, let-7-antagomir negative control (80 mg/kg) was intraperitoneally injected in SCI+NC group at 5 d, an equal amount of let-7-antagomir was intraperitoneally injected in SCI+antagomir group at 5 d, and an equal amount of let-7-mimics was intraperitoneally injected in SCI+mimics group at 5 d. The inflammatory cells in experimental groups and control group were observed via hematoxylin-eosin (HE) staining. At the same time, the expression of let-7 in the four groups was detected via Reverse Transcription-Polymerase Chain Reaction (RT-PCR), the expressions of phosphatidylinositol 3-hydroxy kinase (PI3K) and protein kinase B (Akt) in all groups were detected via Western blotting, and the inflammatory index levels in each group were detected via enzyme-linked immunosorbent assay (ELISA). RESULTS: In Sham group, it was observed via HE staining that there were only a few bleeding or inflammatory cells. In SCI+NC group, bleeding and inflammatory cells basically tended to be stable. There were a large number of inflammatory cells in SCI+mimics group, while there were some inflammatory cells in SCI+antagomir group, but showing a decreasing trend compared with SCI+NC group. It was found in the RT-PCR detection of let-7 expression level in all groups that the expression of let-7 significantly declined in SCI+antangomir group compared with that in Sham group and SCI+NC group, and there were significant differences (p<0.01). The expression of let-7 was significantly increased in SCI+mimics group compared with that in Sham group and SCI+NC group, and there were significant differences (p<0.01). The results of Western blotting revealed that the PI3K and Akt protein expressions were significantly decreased in SCI+mimics group compared with those in SCI+antagomir group, SCI+NC group, and Sham group (p<0.05). The ELISA results showed that the levels of inflammatory factors in SCI+mimics group, SCI+antagomir group, and SCI+NC group were significantly higher than those in Sham group. In SCI+mimics group, the levels of inflammatory factors were abnormally high and reached extremely significant levels (p<0.05), indicating that let-7 promotes the inflammatory response after SCI. CONCLUSIONS: Let-7 participates in the regulation of inflammatory response in SCI through the PI3K/Akt signaling pathway.

GAS5 promotes podocyte injury in sepsis by inhibiting PTEN expression.

OBJECTIVE: To investigate the potential role of long noncoding RNA (lncRNA) growth arrest specific transcript 5 (GAS5) in sepsis-induced podocyte injury and its underlying mechanism. MATERIALS AND METHODS: The sepsis model was established by lipopolysaccharide (LPS) induction in podocytes. The expression levels of Nephrin and GAS5 were detected by quantitative Real-time polymerase chain reaction (qRT-PCR) after LPS induction in podocytes for 12 h, 24 h and 36 h, respectively. Western blot was used to detect the expression level of Nephrin in sepsis-induced podocytes. The mRNA expressions of GAS5 and Nephrin in podocytes were detected after transfection of GAS5 siRNA. Albumin influx in podocytes after GAS5 knockdown was detected by Transwell assay. Western blot was used to detect the protein expression of Snail in sepsis after GAS5 knockdown. The target gene of GAS5 was predicted by bioinformatics analysis. QRT-PCR and Western blot were used to detect the protein and mRNA levels of PTEN (phosphatase and tensin homolog deleted on chromosome ten). Nephrin expression and the albumin inflow after PTEN knockdown were then measured. The expression of PI3K/AKT/GSK3ß was also detected after GAS5 was downregulated while PTEN was upregulated. RESULTS: LPS stimulation downregulated the mRNA expression of Nephrin in podocytes and achieved the lowest level at 24 h. The protein expression change of Nephrin was consistent with its mRNA expression. In the septic state, the albumin influx of podocytes remarkably increased, but the function of podocyte barrier was weakened. Besides, GAS5 expression decreased in a time-dependent manner in LPS-induced podocytes. After GAS5 knockdown by siRNA, Nephrin expression and the function of podocyte barrier were significantly reduced. Snail expression was also upregulated in septic state, and GAS5 knockdown increased the expressions of phosphorylated Snail and PI3K/AKT/GSK3ß. After knockdown of GAS5, the mRNA and protein levels of PTEN significantly decreased, which was contract to the expression of Snail. However, overexpression of PTEN could reverse the promotive effect of GAS5 on PI3K/AKT activation. CONCLUSIONS: GAS5 expression decreased in sepsis-induced podocyte injury, and GAS5 was involved in regulating sepsis-induced podocyte injury by reducing PTEN expression.

Telomerase activity in human development is regulated by human telomerase reverse transcriptase (hTERT) transcription and by alternate splicing of hTERT transcripts.

The correlation between telomerase activity, telomere lengths, and cellular replicative capacity has led to the theory that maintenance of telomere lengths by telomerase acts as a molecular clock to control replicative capacity and senescence. Regulation of this molecular clock may have applications in the treatment of cell aging and tumorigenesis, although little is presently known about the regulation of telomerase activity. To investigate possible mechanisms of regulation, we examined telomerase activity and the expression of the human telomerase RNA subunit and the human telomerase reverse transcriptase protein (hTERT) during human fetal heart, liver, and kidney development. The human telomerase RNA subunit is expressed in all three tissues at all gestational ages examined. hTERT expression correlates with telomerase activity in the liver, where both are expressed at all ages surveyed, and in the heart, where both are present until the 11th gestational week but not thereafter. However, although telomerase activity in the kidney is suppressed after the 15th gestational week, the hTERT transcript can be detected until at least the 21st week. Reverse transcription-PCR using primers within the reverse transcriptase domain of hTERT show the presence of multiple alternately spliced transcripts in these tissues, corresponding to full-length message as well as spliced messages with critical reverse transcriptase motifs deleted. Of note, telomerase activity in the kidney is only present at those gestational ages when full-length hTERT message is expressed (until approximately week 15), with spliced transcripts continuing to be expressed at later stages of development. The tissue-specific and gestational-age dependent expression of hTERT mRNA seen in human development suggests the presence of at least two regulatory mechanisms controlling the activity of telomerase: transcriptional control of the hTERT gene and alternate splicing of hTERT transcripts.

Repression of hepatitis B virus (HBV) transgene and HBV-induced liver injury by low protein diet.

Persistent infection with hepatitis B virus (HBV) is one of the primary risk factors for human hepatocellular carcinoma (HCC). In a human ecological study, we have shown that, in addition to HBV, animal food consumption also significantly contributes to the variance of HCC. To test the interacting effect of HBV and animal food consumption on the development of HCC, we investigated HBV expression in HBV transgenic mice fed three levels of casein diet. HBV expression in transgenic animals was substantially inhibited when dietary casein was reduced from the traditional level of 22% to the level of 6%. Northern analysis revealed that suppression of HBV was derived from both the upstream albumin promoter and the internal HBV promoter. Immunochemical staining of liver sections indicated that only a few hepatocytes around the central vein expressed viral surface antigen (HBsAg) in the 6% casein animals, whereas virtually all hepatocytes stained positively for HBsAg in the 22% dietary casein animals. Serum HBsAg concentrations at 4 months were increased by 1.6-, 2.1-, and 5.1- fold over baseline for animals fed the 6%, 14%, and 22% casein diets, respectively. Correspondingly, liver injury was much less severe in animals fed 6% casein diet than in those fed 14% and 22% casein diets. These results demonstrate that a low casein diet is a potent suppresser of HBV transgene and HBV-induced liver injury, suggesting that diet management may be a practical means to aid in the control HBV infection.

Allelic expression of the putative tumor suppressor gene p73 in human fetal tissues and tumor specimens.

p73, a proposed tumor suppressor, shares significant amino acid sequence homology with p53. However, p73 is rarely mutated in tumors but it has been suggested that p73 is monoallelically expressed in some tissues. This latter feature would predispose p73 to gene inactivation because a single genetic 'hit' or the loss of the expressed parental allele would leave the cell without p73 activity. We examined the allelic expression of p73 in normal fetal tissues and in ovarian cancer and Wilms' tumor. We found that p73 was biallelically expressed in all fetal tissues, except in brain, where differential expression of the two parental alleles was observed. Biallelic expression of p73 was also observed in paired samples of ovary cancer and Wilms' tumor. Loss of heterozygosity of p73 occurred at relatively low rates in tumors: one of 11 informative samples (9.1%) of ovarian cancer and two of 19 (10.1%) Wilms' tumors. These data demonstrate that p73 is biallelically expressed in most tissues, thus excluding genomic imprinting as a molecular mechanism to predispose to allelic inactivation of p73 in human tumors.

Differential biallelic activation of three insulin-like growth factor II promoters in the mouse central nervous system.

Imprinting of the insulin-like growth factor II gene (IGF-II) is conserved in human, rat, and mouse. In human liver and chondrocytes, IGF-II transcripts from promoter hP1 are always derived from both parental alleles, while transcripts from promoters hP2-hP4 are from one parental allele. To examine the promoter-specific imprinting pattern of mouse IGF-II, we examined IGF-II expression in F1 generation mice derived from crossing M. spretus with M. musculus using a novel BsaA1 polymorphism in mouse IGF-II exon 6. There was maintenance of maternal IGF-II imprinting in all non-central nervous system (CNS) tissues in the F1 generation animals. However, there was biallelic expression of the IGF-II gene in CNS. Allelic expression of each IGF-II promoter transcript was examined by full-length cDNA amplification with promoter-specific primers. In every tissue in which IGF-II was imprinted, IGF-II transcripts were derived from paternal promoters mP1-mP3, while the maternal allele was suppressed. In the CNS, however, promoters mP1-mP3 of the imprinted maternal allele became activated, leading to the biallelic expression of IGF-II. Moreover, the expression of IGF-II from each parental allele differed in various CNS regions. In leptomeninges, mP1-mP3 drive IGF-II expression predominantly from the paternal allele, while in some CNS regions, the promoter transcripts were primarily from the maternal allele. The coordinate regulation of mouse IGF-II promoters suggests the presence of an upstream imprinting complex controlling IGF-II imprinting.(ABSTRACT TRUNCATED AT 250 WORDS)

Tissue-specific imprinting of the mouse insulin-like growth factor II receptor gene correlates with differential allele-specific DNA methylation.

Imprinted genes may be expressed uniparentally in a tissue- and development-specific manner. The insulin-like growth factor II receptor gene (Igf2r), one of the first imprinted genes to be identified, is an attractive candidate for studying the molecular mechanism of genomic imprinting because it is transcribed monoallelically in the mouse but biallelically in humans. To identify the factors that control genomic imprinting, we examined allelic expression of Igf2r at different ages in interspecific mice. We found that Igf2r is not always monoallelically expressed. Paternal imprinting of Igf2r is maintained in peripheral tissues, including liver, kidney, heart, spleen, intestine, bladder, skin, bone, and skeletal muscle. However, in central nervous system (CNS), Igf2r is expressed from both parental alleles. Southern analysis of the Igf2r promoter (region 1) revealed that, outside of the CNS where Igf2r is monoallelically expressed, the suppressed paternal allele is fully methylated while the expressed maternal allele is completely unmethylated. In CNS, however, both parental alleles are unmethylated in region 1. The importance of DNA methylation in the maintenance of the genomic imprint was also confirmed by the finding that Igf2r imprinting was relaxed by 5-azacytidine treatment. The correlation between genomic imprinting and allelic Igf2r methylation in CNS and other tissues thus suggests that the epigenetic modification in the promoter region may function as one of the major factors in maintaining the monoallelic expression of Igf2r.

Modulation of Igf2 genomic imprinting in mice induced by 5-azacytidine, an inhibitor of DNA methylation.

The adjacent genes, insulin-like growth factor 2 (Igf2) and H19, are imprinted in both mouse and human. While Igf2 is expressed from the paternal allele, H19 is transcribed exclusively from the maternal allele. To explore the underlying mechanism of Igf2 and H19 imprinting, we studied the effect of DNA demethylation on allelic expression by injecting mice with the demethylating agent 5-azacytidine (5-aza-C). We observed a > or = 2-fold increase in the abundance of Igf2 mRNA in liver from treated mice compared with that of control mice. There was no significant change in Igf2 or H19 expression in brain. In the 5-aza-C-treated mice, there was dramatic modulation of Igf2 imprinting. In some tissues, Igf2 was expressed biallelically, while in other tissues, the paternal allele was silenced and the normally imprinted maternal allele was expressed, an example of allelic switching. There was no change in the normal biallelic pattern of Igf2 expression in brain. H19, on the other hand, remained imprinted in all tissues in mice treated with 5-aza-C. These results provide the first example of a pharmacological manipulation of genomic imprinting of an endogenous gene in vivo and further implicate DNA methylation as an important factor in maintaining the differential allelic expression of the Igf2 gene.

Effects of antibiotics on cellular viability in porcine heart valve tissue.

The purpose of this study was to find an antibiotic disinfecting solution for cardiovascular tissues which would allow maximal cellular viability while maintaining antibacterial and antifungal activity. Cellular viability of porcine heat valves sterilised using antibiotics was assessed by radiolabelled proline transport assays. The results show that storage of valve tissues in RPMI 1640 tissue culture medium (4 degrees C) alone decreases the cellular viability by 50%, 60% and 90% within 12, 24, and 72 h, respectively. Amphotericin B was shown to be the toxic component of the antibiotic sterilising solution recommended by Strickett and coworkers, accounting for all the observed antibiotic toxicity. It reduced the cellular viability by 100% within 12 h of storage at 4 degrees C. Our study also showed that streptomycin is responsible for the loss of cellular viability in the antibiotic medium utilised by O'Brien's group. The results show that after storage of valve tissues for 12 h in O'Brien's antibiotic solution, the cellular viability was reduced by 60%, and after 24 h by 90%. Cefoxitin, lincomycin, polymyxin B, vancomycin and penicillin had no apparent effects on viability of cells in the cardiovascular tissues utilised in this study. In conclusion, heart valve tissue may be sterilised effectively using selective antibiotics without causing significant damage to cellular viability.

Seawater Incursion Events in a Cretaceous Paleo-lake Revealed by Specific Marine Biological Markers.

Many large paleo-lakes in North China were formed after the Triassic Era. Seawater incursion events (SWIEs) in these lakes have been extensively discussed in the literature, yet lack reliable methodology and solid evidence, which are essential for reconstructing and confirming SWIEs. The present study employs specific marine biological markers (24-n-propyl and 24-isopropyl cholestanes) to trace SWIEs in a dated core taken from the Songliao Basin (SLB). Two SWIEs were identified. The first SWIE from 91.37 to 89.00 Ma, was continuous and variable but not strong, while the second SWIE from 84.72 to 83.72 Ma was episodic and strong. SWIEs caused high total organic carbon (TOC) and negative δ(13)Corg values in the sediments, which were interpreted as an indication of high productivity in the lake, due to the enhancement of nutrient supplies as well as high levels of aqueous CO2, due to the mixing of alkaline seawater and acidic lake water. The SWIEs in SLB were controlled by regional tectonic activity and eustatic variation. Movement direction changes of the Izanagi/Kula Plate in 90 Ma and 84 Ma created faults and triggered SWIEs. A high sea level, from 90 to 84 Ma, also facilitated the occurrence of SWIEs in SLB.