Mapping intellectual structures and research hotspots in the application of artificial intelligence in cancer: A bibliometric analysis.

Background: Artificial intelligence (AI) is more and more widely used in cancer, which is of great help to doctors in diagnosis and treatment. This study aims to summarize the current research hotspots in the Application of Artificial Intelligence in Cancer (AAIC) and to assess the research trends in AAIC. Methods: Scientific publications for AAIC-related research from 1 January 1998 to 1 July 2022 were obtained from the Web of Science database. The metrics analyses using bibliometrics software included publication, keyword, author, journal, institution, and country. In addition, the blustering analysis on the binary matrix was performed on hot keywords. Results: The total number of papers in this study is 1592. The last decade of AAIC research has been divided into a slow development phase (2013-2018) and a rapid development phase (2019-2022). An international collaboration centered in the USA is dedicated to the development and application of AAIC. Li J is the most prolific writer in AAIC. Through clustering analysis and high-frequency keyword research, it has been shown that AI plays a significantly important role in the prediction, diagnosis, treatment and prognosis of cancer. Classification, diagnosis, carcinogenesis, risk, and validation are developing topics. Eight hotspot fields of AAIC were also identified. Conclusion: AAIC can benefit cancer patients in diagnosing cancer, assessing the effectiveness of treatment, making a decision, predicting prognosis and saving costs. Future AAIC research may be dedicated to optimizing AI calculation tools, improving accuracy, and promoting AI.

ZNF384-ZEB1 feedback loop regulates breast cancer metastasis.

BACKGROUND: Breast cancer has become the most frequently diagnosed cancer worldwide. Increasing evidence indicated that zinc finger proteins (ZNFs), the largest family of transcription factors, contribute to cancer development and progression. Although ZNF384 is overexpressed in several types of human cancer, the role of ZNF384 in breast cancer remains unknown. Therefore, our research focused on ZNF384 regulation of the malignant phenotype of breast cancer and the underlying molecular mechanisms. METHODS: CCK-8 and colony formation assays were used to evaluate cell proliferation. Transwell and scratch assays were used to evaluate the cell migration and invasion. Chromatin immunoprecipitation (ChIP)-qPCR and luciferase reporter assays were used to confirm the target relationship between ZNF384 and zinc finger E-box binding homeobox 1 (ZEB1). Xenografts were used to monitor the targets in vivo effects. RESULTS: We noted that ZNF384 was significantly overexpressed in breast cancer and highlighted the oncogenic mechanism of ZNF384. ZNF384 transactivated ZEB1 expression and induced an epithelial and mesenchymal-like phenotype, resulting in breast cancer metastasis. Furthermore, ZNF384 may be a target of miR-485-5p, and ZEB1 can up-regulate ZNF384 expression by repressing miR-485-5p expression. Together, we unveiled a feedback loop of ZNF384-ZEB1 in breast cancer metastasis. CONCLUSIONS: The findings suggest that ZNF384 can serve as a prognostic factor and a therapeutic target for breast cancer patients.

Microglia-derived TNF-α inhibiting GABAergic neurons in the anterior lateral bed nucleus of the stria terminalis precipitates visceral hypersensitivity induced by colorectal distension in rats.

Irritable bowel syndrome (IBS) is a common and debilitating gastrointestinal disorder that is exacerbated by stress and characterized by abdominal pain. Although microglia in the CNS have been implicated as an important mediator of the stress response, the role of microglia and microglia-GABAergic neuron interactions in the limbic area, most notably BNST, in the development of colorectal hypersensitivity has not been determined. We established a neonatal colorectal distension-induced chronic visceral hyperalgesia model in rats. The results showed that the frequency of spontaneous discharges of alBNST GABAergic neurons and the expression of GAD65/67 were significantly decreased in rats with chronic visceral pain. Moreover, ablation of BNST GABAergic neurons significantly reduced the visceral pain threshold in normal rats. Meanwhile, the number of M1 proinflammatory microglia and the expression of the M1 proinflammatory microglia-derived cytokines IL-6 and TNF-α were increased in the alBNST of rats with chronic visceral pain. Furthermore, alBNST infusion of the microglial inhibitor minocycline or IL-6 and TNF-α neutralizing antibodies significantly increased the visceral pain threshold. The decreased frequency of spontaneous discharges of alBNST GABAergic neurons in rats with chronic visceral pain was mimicked by a bath perfusion of TNF-α, but not IL-6, and was abolished by a perfusion of the microglial inhibitor minocycline. In addition, the alBNST infusion of the microglial inhibitor minocycline upregulated the expression of GAD65/67. Moreover, ablation of BNST GABAergic neurons significantly decreased the visceral pain threshold in normal rats, which was not reversed by a subsequent infusion of the microglial inhibitor minocycline. Our findings revealed this microglia-GABAergic neuron circuit in the alBNST, and this microglia-driven disinhibitory mechanism is essential for brain and gut dysfunction in stressful condition, providing a novel potential target for treating patients with IBS presenting visceral pain that is worsened during episodes of stress.

The functions and prognostic value of Krüppel-like factors in breast cancer.

BACKGROUND: Krüppel-like factors (KLFs) are zinc finger proteins which participate in transcriptional gene regulation. Although increasing evidence indicate that KLFs are involved in carcinogenesis and progression, its clinical significance and biological function in breast cancer are still limited. METHODS: We investigated all the expression of KLFs (KLF1-18) at transcriptional levels by using Oncomine and Gene Expression Profiling Interactive Analysis (GEPIA). The mRNA and protein expression levels of KLFs were also determined by using RT-qPCR and immunohistochemistry, respectively. CBioPortal, GeneMANIA and STRING were used to comprehensive analysis of the molecular characteristics of KLFs. The clinical value of prognostic prediction based on the expression of KLFs was determined by using the KM plotter. The relevant molecular pathways of KLFs were further analyzed by using Gene Set Enrichment Analysis (GSEA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database. Finally, we investigated the effect of KLF2 and KLF15 on biological behavior of breast cancer cells in vitro. RESULTS: The expression of KLF2/4/6/8/9/11/15 was significantly down-regulated in breast cancer. The patients with high KLF2, KLF4 or KLF15 expression had a better outcome, while patients with high KLF8 or KLF11 had a poor prognosis. Furthermore, our results showed that KLF2 or KLF15 can be used as a prognostic factor independent on the other KLFs in patients with breast cancer. Overexpression of KLF2 or KLF15 inhibited cell proliferation and migration, and blocked cell cycle at G0/G1 phase, resulting in cell apoptosis. CONCLUSIONS: KLF2 and KLF15 function as tumor suppressors in breast cancer and are potential biomarkers for prognostic prediction in patients with breast cancer.

Downregulation of MCM2 contributes to the reduced growth potential of epithelial progenitor cells in chronic nasal inflammation.

BACKGROUND: Recent studies have shown that human nasal epithelial progenitor cells (hNEPCs) are characterized by poor proliferation capacities during chronic nasal inflammation. OBJECTIVE: We sought to investigate the key molecular functions and candidates that contribute to the reduced growth potential of hNEPCs in chronically inflamed nasal mucosa. METHODS: Nasal biopsy specimens were obtained from 28 patients with nasal polyps (NPs) and 13 healthy controls. hNEPCs from nasal samples were cultured for 3 consecutive passages, and their molecular and functional profiles were analyzed by RNA sequencing. The minichromosome maintenance protein (MCM) family gene MCM2 was validated in hNEPCs and tissue samples from patients with NPs and control subjects by cell cycle, quantitative PCR, and Western blot analyses; small interfering RNA-mediated knockdown assay; and immunofluorescent staining. RESULTS: Compared with control hNEPCs, NP-derived hNEPCs showed (1) reduced growth kinetics, as evidenced by the colony-forming efficiency and doubling time; (2) inhibited cell cycle progression, as evidenced by gene ontology and/or pathway and cell cycle analyses; and (3) downregulated expression of MCM2, the key protein of the MCM complex, which is critical for DNA replication at the G1/S checkpoint. Moreover, hNEPCs with MCM2 knockdown showed a decreased proliferation rate, and the MCM2 protein level in basal cells was significantly lower in abnormally remodeled nasal epithelium than in normal epithelium. CONCLUSION: These results demonstrate inhibited cell cycle progression and MCM2 downregulation in basal or progenitor nasal epithelial cells from NP tissue, which may contribute to the decreased growth potential of hNEPCs in chronically inflamed upper airways.

Disinhibition of PVN-projecting GABAergic neurons in AV region in BNST participates in visceral hypersensitivity in rats.

Ample evidence suggests that early life stress (ELS) is a high-risk factor for the development of visceral pain disorders, whereas the mechanism underlying neuronal circuit remains elusive. Herein, we employed neonatal colorectal distension (CRD) to induce visceral hypersensitivity in rats. A combination of electrophysiology, pharmacology, behavioral test, molecular biology, chemogenetics and optogenetics confirmed that CRD in neonatal rats could predispose the elevated firing frequency of the parvocellular corticotropin-releasing hormone (CRH) neurons in the paraventricular nucleus of hypothalamus (PVN) in adulthood, with the CRH neurons activated and the frequency of spontaneous inhibitory postsynaptic currents (sIPSC) diminished, both contributing to chronic visceral hypersensitivity. Moreover, following administration of exogenous GABA (300 mM/0.5 µL) and GABAA receptor agonist muscimol (3 mM/0.5 µL) in PVN, visceral hyperalgesia was abrogated. In addition, the PVN-projecting GABAergic neurons were mainly distributed in the anterior ventral (AV) region in the bed nucleus of stria terminalis (BNST), and the excitability of these GABAergic neurons was weakened in visceral hypersensitivity. Specific depletion of the GABAergic neurons in AV region precipitated visceral hyperalgesia. Moreover, chemogenetic activation of the PVN-projecting neurons alleviated the visceral hypersensitivity. Photoactivation of PVN-projecting GABAergic neurons abated the visceral hypersensitivity in neonatal-CRD rats, whereas photoinhibition evoked visceral hyperalgesia in naïve rats. Our findings demonstrated that disinhibition of the PVN-projecting GABAergic neurons in AV region contributed to the excitation of CRH neurons, thereby mediating visceral hypersensitivity. Our study might provide a novel insight into the neuronal circuits involved in the ELS-induced visceral hypersensitivity.

CTL-Derived Granzyme B Participates in Hippocampal Neuronal Apoptosis Induced by Cardiac Arrest and Resuscitation in Rats.

Hippocampal neuronal apoptosis is a devastating consequence of cardiac arrest (CA) and subsequent cardiopulmonary resuscitation (CPR). In this study, we assessed the contribution of cytotoxic T lymphocyte (CTL)-derived toxic mediator granzyme B (Gra-b) to the hippocampal neuronal apoptosis following CA/CPR in rats. Rats that experienced CA/CPA presented with cytosomal shrinkage, dense cytoplasm, and intensive eosinophilic staining in the CA1 region of dorsal hippocampus. CA/CPR rats also exhibited inability in spatial navigation and a local infiltration of peripheral CD8+ T cells into the hippocampus. The protein levels of Gra-b, cleaved Caspase-3, and cleaved PARP1 were significantly elevated in rats undergoing CA/CPR. Pretreatment with Gra-b inhibitor suppressed Gra-b release, attenuated hippocampal neuronal apoptosis, as well as improved cognitive impairment. Together, this study indicates that CTL-derived Gra-b is involved in the CA/CPR-induced neuronal apoptosis, and pharmacological manipulation of Gra-b may represent a novel avenue for the treatment of brain injury following CA/CPR.

[Lymphocytic Clonal Expansion in Adult Patients with Epstein-Barr Virus-Associated Lymphoproliferative Disease].

OBJECTIVE: To explore the lymphocytic clonal expansion in adult patients with Epstein-Barr virus-associated lymphoproliferative diseases (EBV+LPD), and to investigate the experimental methods for EBV+LPD cells so as to provide a more objective measure for the diagnosis, classification and prognosis in the early stage of this disease. METHODS: Peripheral blood samples from 5 patients with EBV+LPD, 4 patients with adult infectious mononucleosis(IM) as negative control and 3 patients with acute NK-cell leukemia(ANKL) as positive control were collected. Prior to immunochemotherapy, viral loads and clonality were analysed by flow cytometry (FCM), T cell receptor gene rearrangement (TCR) was detected by real-time polymerase chain reaction (RT-PCR), and diversity of EB virus terminal repeat (EBV-TR) was detected by Southern blot. RESULTS: FCM showed only 1 case with clonal TCRVß in 5 patients with EBV+LPD, TCR clonal expansion could be detected both in patients with IM(4 of 4) and 4 patients with EBV+LPD(4 of 5), Out of patients with EBV+LPD, 1 patient displayed a monoclonal band and 2 patients showed oligoclonal bands when detecting EBV-TR by southen blot. CONCLUSION: Detecting the diversity of EBV-TR by Southern blot may be the most objective way to reflex clonal transformation of EBV+LPD, which is of great benefit to the diagnosis, classification and prognosis in the early stage of this disease.

[Clinical Analysis of 10 Cases of B Cell Lymphoma-Associated Hemophagocytic Syndrome].

OBJECTIVE: To investigate the clinical and laboratory features of patient with B cell lymphoma associated hemophagocytic syndrome(B-LAHS). METHODS: The clinical data of 10 cases of B-LAHS were retrospectively analysed and the relevant literatures were reviewed. RESULTS: The median age of 10 cases diagnosed as B-LAHS was 55.5 (31-88) years old, and median time from attack to diagnosis was 2 months (2 weeks-4 months). The diagnosis can be made histopathologically and immunohistochemically by bone marrow biopsy. Among them 7 cases were diagnosed as large B cell lymphoma, 2 cases as mantle cell lymphoma and 1 case as small B cell lymphoma. The prominent clinical symptoms and signs were persistent fever (100%) and splenomegaly(90%), and the involvements with respiratory and digestive system were common. Another 1 case had systemic muscle pain and lactic acidosis as the first onset. Laboratory studies showed hepatic dysfunction, significantly elevated ferritin and lactate dehydrogenase, abnormal lymphocytes in peripheral blood smear, and hemophagocytosis in bone marrow smear. The FSC/SSC abnormalities of cloned B lymphoma cells were detected through flow cytometry (FCM). The complete remission (CR) was maintained in 4 cases receiving immunochemotherapy based on rituximab. CONCLUSION: B-LAHS possesses heterogeneous clinical manifestations and rapid deterioration. Bone marrow biopsy and immunohistochemical examination can confirm the diagnosis. FCM may improve the early diagnosis of B-LAHS.

Molecular and immune response characterizations of IL-6 in large yellow croaker (Larimichthys crocea).

Interleukin-6 (IL-6) is a multifunctional inflammatory cytokine which exists in multiple tissues and cell lines. In the present study, the full-length cDNA and the genomic sequence of IL-6 (LcIL-6) were cloned from large yellow croaker, Larimichthys crocea. The full-length cDNA of LcIL-6 was 1066 base pairs (bp), containing an open reading frame (ORF) of 678 bp encoding for 225 amino acids, a 5' untranslated region (UTR) of 71 bp and a 3' UTR of 317 bp. The predicted LcIL-6 protein included a 24 amino acids (aa) signal peptide and a conserved IL-6 domain. However, the polypeptide sequence identities between LcIL-6 and its counterparts in mammals and other fish are from 12% to 45%. The genome sequence of LcIL-6 gene was composed of 2126 bp, including five exons and four introns. Phylogenetic analysis revealed that LcIL-6 showed a close relationship with the IL-6 from other bony fish. Quantitative real-time PCR (qRT-PCR) analysis revealed that LcIL-6 mRNA was expressed in most examined tissues, with the most predominant expression in stomach, followed by blood and very weak expression in other tissues. The expression levels of LcIL-6 after challenged with LPS, poly I:C and Vibrio parahaemolyticus were investigated in spleen, head-kidney and liver. LcIL-6 transcripts were induced significantly after immune challenge, with the peak-value of 33.5 times as much as the control in the head-kidney at 3 h after LPS injection (p < 0.05). Overexpression of LcIL-6 enhanced tumor necrosis factor (TNF)-α transcripts significantly (p < 0.05) in L. crocea kidney (LCK) cells. Additionally, recombinant LcIL-6 mature peptide was obtained in the supernatant of Escherichia coli BL21 (DE3). The purified recombinant LcIL-6 fusion protein was also demonstrated to improve the transcriptional expression levels of TNF-α significantly in LCK cells (p < 0.05). However, no significant changes of Mx (myxovirus resistant protein), IL-1ß, janus kinase (JAK)2, signal transducers and activators of transcription (STAT)3 and STAT5 in LCK cells was detected after LcIL-6 overexpression or recombinant LcIL-6 protein stimulation. Our results indicated that LcIL-6 might be important in large yellow croaker immune response and improve the inflammatory response by through activation TNF-α expression.

Comparison of active dry yeast (Saccharomyces cerevisiae) and yeast culture for growth performance, carcass traits, meat quality and blood indexes in finishing bulls.

This study was conducted to compare the effect of active dry yeasts (ADY) and yeast cultures (YC), two typical products of yeast preparations, on growth performance, carcass characteristics, meat quality and blood indexes in finishing bulls fed a high-concentrate diet. Forty-five finishing bulls (mean body weight (BW) ± standard deviation: 505 ± 29 kg BW) were allocated to three groups of 15 bulls and assigned randomly to one of three diets which were CON diet (basal diet), ADY diet (basal diet + Levucell SC) and YC diet (basal diet + Diamond V XP), respectively. After 98 days of trial, all bulls were slaughtered. The result showed that ADY rather than YC improved growth performance and carcass traits of bulls compared to CON. Moreover, both ADY and YC improved beef tenderness and changed blood indexes related to fat metabolism. In conclusion, ADY had more pronounced effect on growth performance of bulls fed high-concentrate diet, and both ADY and YC improved the beef quality by intensive fat metabolism.

Environmental Kuznets curve analysis of the economic development and nonpoint source pollution in the Ningxia Yellow River irrigation districts in China.

This study applies the environmental Kuznets curve to test the relationship between the regional economic growth and the different types of agricultural nonpoint source pollution loads in the Ningxia Yellow River irrigation area by using the Johnes export coefficient method. Results show that the pollution load generated by crop cultivation and livestock-breeding industries in the Ningxia Yellow River irrigation area shows an inverted U-shaped feature; however, this feature is absent in living-sewage pollution load. Crop pollution has shown a decreasing trend since 1997 because of the increased per capita income of farmers. Livestock-breeding pollution load reached its turning point when the per capita income of farmers reached 8386.74 RMB. Therefore, an increase in the per capita income of farmers corresponds to an increase in the livestock-breeding pollution load in the Ningxia Yellow River irrigation area.

[Clinical features and laboratory findings of adult Epstein-Barr virus associated T/NK lymphoproliferative disease].

The aim of this study was to analyze the clinical features and laboratory findings of adult Epstein-Barr virus associated T/NK cell lymphoproliferative disease (EBV+T/NK-LPD) and to investigate the early diagnosis and prognosis of EBV+T/NK-LPD. The clinical data of 19 adult patients with EBV+T/NK-LPD were retrospectively analyzed. The results indicated that there were 11 males and 8 females. The median age was 32 years (range: 20-70 years). The average duration from onset of symptoms to diagnosis was 3.5 months. The median survival time was 2.5 months. Unkown fever, hepatosplenomegaly, liver dysfunction and interstitial pneumonia were the main clinical features. High levels of ß2-MG, LDH, TNF, IL-6 and significantly increased EBV-DNA level (median level > 10(6) copies/ml) were occurred in all the patients. Cytopenia was seen in 18 cases. Morphologically, atypical large granular lymphocytes and hemophagocytosis were common in bone marrow smears. Deletion of CD5 or CD7 were frequently observed in T/NK lymphocytes in bone marrow cells by flow cytometry. Bone marrow biopsy showed atypical lymphocyte interstitial infiltrated in 10 cases, while a few large cells infiltrated in 6 cases. Immunohistochemistry showed the expression of CD3(+)CD56(+) were seen in 2 cases, CD3(+)CD8(+) in 11 cases and CD3(+)CD4(+) in 3 cases. TIA-1 and EBER were positive in all biopsy specimens. Three cases underwent biopsy of lymph nodes showed reactive proliferations of lymphocytes. All the patients died of multiorgan failure. It is concluded that the fever, hepatosplenomegaly are the most common clinical features in adult EBV+T/NK-LPD, the bone marrow infiltration of EBV-infected T/NK lymphocytes and significantly increased EBV-DNA level can be observed in all cases, the clinical outcome of this disease is poor, these clinical and experimental features can be served as a reliable marker for the timely diagnosis of adult EBV+T/NK-LPD.

[Clinical analysis of 10 patients with de novo CD5 positive diffuse large B cell lymphoma].

To explore the clinical characteristics, diagnosis, treatment outcome and prognosis of de novo CD5 positive diffuse large B cell lymphoma (CD5(+)DLBCL), clinical data of 10 patients with pathologically confirmed CD5(+)DLBCL were retrospectively analyzed. The results indicated that 9 out of 10 patients were older than 60 years. All cases were in III/IV stages according to Ann-Arbor Staging System. Bone marrow biopsy with immunohistochemistry showed lymphoma involvement in 5 cases. Nine patients received chemotherapy with anti-CD20 monoclonal antibody (Rituximab) except one. Five cases achieved CR, two cases achieved PR, two cases achieved SD, one case achieved PD. Eight cases died within 2 years because of relapse or disease progression, in which 3 cases developed central nervous system lymphoma. The median survival time was 16 (1-23) months, 2-year survival rate was 20.40%. It is concluded that de novo CD5(+) DLBCL is rare in clinic, but it is a kind of highly aggressive lymphoma with poor prognosis. So, new treatment strategy should be explored.

[Research on using near infrared diffuse reflectance spectroscopy for rapid prediction of compositions of steamed-flaking corn].

Near infrared diffuse reflectance spectroscopy (NIDRS) calibrations of chemical composition in 62 kinds of steamed-flaking corn were developed by partial least squares (PLS) regression. The calibration models were constructed by the mean centre + first deviation + multivariate scattering calibration in the square regions (950-1 650 nm). Results showed that the R2(VaL) are 0.951 1, 0.903 2, 0.714 3 and 0.908 2 for CP, NDF, ADF and EE respectively. The SECV are 1.53, 1.89, 2.45 and 0.50 for CP, NDF, ADF and EE respectively. Therefore, the models could be used to predict the content of CP, NDF and EE in steamed-flaking corn and provide a fast and economical method for quality control of steamed-flaking corn.

[Near infrared reflectance spectroscopy (NIRS) and its application in the determination for the quality of animal feed and products].

Near-infrared reflectance spectroscopy (NIRS) has been the most rapidly developing and noticeable spectrographic analytical technique in recent years. The determining principle and progresses of near-infrared reflectance spectroscopy are presented briefly. It mainly includes the progresses in pre-processing technique and analyzing model of near-infrared reflectance spectroscopy. Two pre-processing techniques, including differential coefficient-dealt with technique, the signal-smoothing technique, and four analyzing models of near-infrared spectroscopy, including the multiplied lined regression (MLR), principal component analysis (PCA), partial least squares (PLS), and artificial nerve network (ANN). The application of near-infrared reflectance spectroscopy to the first time. The investigation of reviewed papers shows that the near-infrared reflectance spectroscopy is widely applied in feed analysis and animal products analysis because of its rapidness, non-destruction and non-pollution. The near infrared reflectance spectroscopy has been used to determine the feed common ingredient, such as dry matter, crude protein, crude fiber, crude fat and so on, micro-components including amino acid, vitamin, and noxious components, and to determine the physical and chemical properties of animal products which including egg, mutton, beef and pork. Details of the analytical characteristics of feed and animal products described in the reviewed papers are given. New trends and limits to the application of near-infrared reflectance spectroscopy in these fields are also discussed.

[Rapid evaluation of beef quality by NIRS technology].

The aim of the present study was to develop a near-infrared reflectance (NIR) spectroscopy rapid method for evaluation of beef quality. Partial least squares (PLS) prediction model for the physic-chemical characteristics such as moisture, fat, protein, pH, color and WBSF in beef was established with good veracity. One hundred fourteen samples from five different parts of beef carcass (tenderloin, ribeye, topside, shin, striploin) were collected from meat packer after 48 h aging. Spectra were obtained by scanning sample from 950 to 1 650 nm and pretreated the model by MSC, SNV and first derivative. Predictive correlation coefficients of physic-chemical parameters in beef were 0.947 2 (moisture), 0.924 5 (fat), 0.934 6 (protein), 0.620 2 (pH), 0.820 3 (L), 0.864 6 (a*), 0.753 0 (b*) and 0.475 9 (WBSF) respectively. Root mean square errors of calibration (RMSEC) were 0.313 3 (moisture), 0.221 0 (fat), 1.243 2 (protein), 0.744 6 (pH), 1.778 3 (L*), 1.394 2 (a*), 1.763 9 (b*) and 1.0743 (WBSF). They were externally validated with additional 30 beef samples. Statistics showed that there was no significant difference between predicted value and those obtained with conventional laboratory methods. The results showed that NIRS is a rapid, effective technique for evaluating beef quality. The predictions for chemical characteristics gave higher accuracy than prediction for physical characteristics.

[Study of the interaction of atrazine and ct-DNA by fluorescence probe technique].

The interaction atrazine and ct-DNA was studied using fluorescence probe and UV absorption spectroscopy technique. Ethidium bromide (EB) was used as a probe. The effects of atrazine, phosphate, concentration of ions, and potassium iodide on the fluorescence of ct-DNA-EB system were investigated. The results showed that the fluorescence quenching process of atrazine to ct-DNA-EB system was proved to be the simultaneous dynamic and static quenching model. The phenomena of fluorescence quenching of ct-DNA-atrazine system by KI and hyperchromicity and the red shift of DNA UV-absorption caused by atrazine indicated the existence of intercalation between atrazine and ct-DNA. The experiments of phosphate and ionic strength showed that atrazine could combine with the phosphate group of ct-DNA by non-characteristic static force, and this action could be inhibited by high ionic strength.

[Interaction of ctDNA and EGCG-Cu(II) complex].

The fluorescence spectra, absorption spectra and resonance light scattering (RLS) spectra of EGCG-Cu((II) complex with nucleic acid were studied. Compared with the spectrum of EGCG-Cu(II), the spectrum of EGCG-Cu(II)-DNA system showed the following features: (1) in the fluorescence spectra, the peak did not shift, but the fluorescence intensity was enhanced and was proportional to the concentration of DNA. Under suitable conditions, EGCG-Cu(II) promised to be a probe for detecting DNA; (2) Absorption spectra of EGCG-Cu(II)-DNA system showed hyperchromicity; and (3) RLS of EGCG-Cu(II)-DNA system was enhanced also. A mechanism was suggested that the combination of nucleic acid and EGCG-Cu(II) complex was caused by intercalation and electrostatic force. An intercalation interaction between EGCG-Cu(II) and DNA enhanced the fluorescence intensity. Hyperchromicity of absorption spectra and RLS occurred because of electrostatic force. The effects of acid and ionic strength on fluorescence intensity were also discussed.

[Prediction of IVDMD with near infrared reflectance spectroscopy (NIRS) in maize stalk].

The in vitro dry matter digestion (IVDMD) in maize stalk was analyzed with 161 samples selected from 600 samples of different eco-environments, hybrids and inbred lines, development stages, and various parts of the plants in two years. The technique of near infrared reflectance spectroscopy (NIRS) and partial least square regression (PLS) were used to establish the models by comparing several preprocessing procedures and wavelength ranges. The optimal models could be obtained in the range of 6 101. 7-5 773. 8 cm(-1) and 4 601. 3-4 246. 5 cm(-1) by the spectral data preprocessing of the Max-Min normalization. The model is suitable for measuring various sample IVDMD. The determination coefficients of the modes were 0.907 3 and 0.906 6 for cross and external validation, respectively. The root mean square error of prediction was 2.08%, and the coefficient of correlation(r) was 0.956 between NIRS predicted and actual IVDMD in these materials. The results showed that NIRS is a simple effective means for measuring IVDMD in maize stalk. The results are of great value of application in screening and evaluating quality constituents of silage maize.