The dynamic mechanical response and deformation mechanism of magnesium-yttrium alloy at high strain rate were investigated using split-Hopkinson pressure bar(SHPB)impact,and the microstructure evolution and crack form...The dynamic mechanical response and deformation mechanism of magnesium-yttrium alloy at high strain rate were investigated using split-Hopkinson pressure bar(SHPB)impact,and the microstructure evolution and crack formation mechanism were revealed.The yield strength and work hardening rate increase significantly with increasing impact strain rate.Deformation twinning and non-basal dislocation slip are the primary deformation mechanisms during testing.Contrary to crack initiation mechanism facilitated by adiabatic shear bands,we find that high-density co-axial nanocrystalline grains form near cracks,which leads to local softening and promotes crack initiation and rapid propagation.Most grains have similar<1^(-)21^(-)0>orientations,with unique misorientation of 24°,32°,62°,78°and 90°between adjacent grains,suggesting that these grains are primarily formed by interface transformation,which exhibits distinct differences from recrystallized grains.Our results shed light upon the dynamic mechanical response and crack formation mechanism in magnesium alloys under impact deformation.展开更多
Developing efficient photocatalysts to address collaborative energy and environmental crises still faces significant challenges.In this report,we present a highly efficient MXene–based photocatalyst,which is combined...Developing efficient photocatalysts to address collaborative energy and environmental crises still faces significant challenges.In this report,we present a highly efficient MXene–based photocatalyst,which is combined with MoS_(2)nano patches and TiO_(2)/Ti_(3)C_(2)(TTC)nanowires through hydrothermal treatment.Of all the composites tested,the optimized photocatalyst gave a remarkable H_(2)and revolving polylactic acid(PLA)into pyruvic acid(PA).Achieving a remarkable H_(2)evolution rate of 637.1 and 243.2μmol g^(−1)h^(−1),in the presence of TEOA and PLA as a sacrificial reagent under UV-vis(λ≥365 nm)light irradiation.The improved photocatalytic activity is a result of the combination of dual cocatalyst on the surface of TTC photocatalyst,which create an ideal synergistic effect for the generation of PA and the production of H_(2)simultaneously.The MoS_(2)TiO_(2)/Ti_(3)C_(2)(MTT)composite can generate more photoexcited charge carriers,leading to the generation of more active radicals,which may enhance the system's photocatalytic activity.This work aims at demonstrating its future significance and guide the scientific community towards a more efficient approach to commercializing H_(2)through photocatalysis.展开更多
BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. We analyzed the expression of miclear-transcription factor-kappa B (NF-kappa B) during hepatocarcinogenesis in order to evaluate i...BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. We analyzed the expression of miclear-transcription factor-kappa B (NF-kappa B) during hepatocarcinogenesis in order to evaluate its dynamic expression and its clinical value in the development and diagnosis of HCC. METHODS: Hepatoma models were induced by oral administration of 2-acetamidoflurene (2-FAA) to male Sprague-Dawley rats. Morphological changes were observed after hematoxylin and eosin staining. The cellular distribution of NF-kappa B expression during different stages of cancer development was investigated by immunohistochemistry, and the level of NF-kappa B expression in liver tissues was quantitatively analyzed by ELISA. The gene fragments of hepatic NF-kappa B were amplified by nested-polymerase chain reaction assay. RESULTS: Hepatocytes showed vacuole-like degeneration during the early stages, then had a hyperplastic nodal appearance during the middle stages, and finally progressed to tubercles of cancerous nests with high differentiation. The NF-kappa B-positive material was buff-colored, fine particles localized in the nucleus, and the incidence of NF-kappa B-positive cells was 81.8% in degeneration, 83.3% in precancerous lesions, and 100% in cancerous tissues. All of these values were higher than those in controls (P<0.01). Hepatic NF-kappa B expression and hepatic NF-kappa B-mRNA were also higher during the course of HCC development (P<0.01). CONCLUSION: The NF-kappa B signal transduction pathway is activated during the early stages of HCC development, and its abnormal expression may be associated with the occurrence of HCC.展开更多
Based on the minimum principle of acceleration in the elastic-plastic continua under finite def ormation, the dynamic response of an elastic-perfectly plastic pin-ended beam subjected to rectangular impulse loading is...Based on the minimum principle of acceleration in the elastic-plastic continua under finite def ormation, the dynamic response of an elastic-perfectly plastic pin-ended beam subjected to rectangular impulse loading is studied with the help of a numerical approach. The calculated results once again show the anomalous behavior of the beam during its response process, which was previously found in [1]. By carefully analyzing the instantaneous distribution of the bending moment, the membrane force, the curvature and displacement during the response process, it is concluded that the interactive effect between the geometry and materials nonlinearities of the structure is the key reason for leading to the anomalous behavior. This will be helpful for clarifying some misunderstandings in explaining the problem before.展开更多
BACKGROUND: Recent studies have confirmed that the expression of Ezrin, hepatocyte growth factor (HGF) and its receptor (C-met) is related to the genesis, progress, invasion and metastasis of some malignant tumors. Re...BACKGROUND: Recent studies have confirmed that the expression of Ezrin, hepatocyte growth factor (HGF) and its receptor (C-met) is related to the genesis, progress, invasion and metastasis of some malignant tumors. Researches have also found that the biological function of Ezrin is closely related to HGF/C-met in malignant tumors. However, there is no report on the expression levels of Ezrin, HGF and C-met in rat pancreatic cancer induced by dimethylbenzanthracene (DMBA). This study aimed to detect the expression of Ezrin, HGF and C-met in rat pancreatic cancer and non-cancerous pancreatic tissues, and assess its effect in cancer induction by DMBA. METHODS: Ninety Sprague-Dawley rats were divided into 3 groups randomly: 40 in a pancreatic cancer model group (group A), 40 in a trichostatin A (TSA) intervention group (group B), and 10 in a control group (group C). DMBA was directly implanted into the parenchyma of rat pancreas in group A+group B. The rats of group B were treated with 1 ml of TSA saline solution (1 mu g/ml) via intraperitoneal injection weekly. The carcinogenesis of rats executed within 3-5 months in groups A and B was observed by macrograph and microscopy. Meanwhile, the rats in group C were executed within 5 months. The EnVision (TM) immunohistochemistry for detecting the expression levels of Ezrin, HGF and C-met was used in paraffin-embedded sections of the pancreatic specimens. RESULTS: The incidence of pancreatic cancer in group A was 48.6% and in group B 33.3%. The maximal diameter of tumor mass was significantly larger in group A than that in group B (P<0.05). No pathological changes were observed in the pancreas of group C and other main organs of groups A and B. The positive rates of Ezrin, HGF and C-met were significantly higher in ductal adenocarcinoma than in non-cancerous pancreatic tissues of groups A and B (P<0.01). The positive rates of Ezrin, HGF and C-met were significantly higher in ductal adenocarcinoma of group A than those in non-cancerous pancreatic tissues of group A (P<0.05), but there was no significant difference in group B (P>0.05). The positive rates of Ezrin, HGF and C-met in non-cancerous pancreatic tissues proved mild to severe atypical hyperplasia of the ductal epithelia. The pancreas of group C and 2 cases of fibrosarcoma showed the negative expression of Ezrin, HGF and C-met. There was a trend of consistency in the expression of Ezrin, HGF and C-met in ductal adenocarcinoma (P<0.05 or P<0.01). CONCLUSIONS: DMBA directly implanted into the parenchyma of the pancreas can produce a model of pancreatic cancer with a high incidence in a short time. TSA might inhibit the carcinogenesis and growth of pancreatic cancer, and its effects may be related to the inhibition of the expression of Ezrin, HGF and C-met during the process. Ezrin, HGF and C-met may have positive effects on the carcinogenesis of rat pancreas. (Hepatobiliary Pancreat Dis Int 2010; 9: 639-644)展开更多
AIM To understand the molecular mechanism of esophageal cancer development and provide molecular markers for screening high-risk populations and early diagnosis. METHODS Two-dimensional electrophoresis combined with m...AIM To understand the molecular mechanism of esophageal cancer development and provide molecular markers for screening high-risk populations and early diagnosis. METHODS Two-dimensional electrophoresis combined with mass spectrometry were adopted to screen differentially expressed proteins in nine cases of fetal esophageal epithelium, eight cases of esophageal cancer, and eight cases of tumor-adjacent normal esophageal epithelium collected from fetuses of different gestational age, or esophageal cancer patients from a high-risk area of esophageal cancer in China. Immunohistochemistry(avidin-biotin-horseradish peroxidase complex method) was used to detect the expression of peroxiredoxin(PRX)6 in 91 cases of esophageal cancer, tumoradjacent normal esophageal tissue, basal cell hyperplasia, dysplasia, and carcinoma in situ, as well as 65 cases of esophageal epithelium from fetuses at a gestational age of 3-9 mo.RESULTS After peptide mass fingerprint analysis and search of protein databases, 21 differential proteins were identified; some of which represent a protein isoform. Varying degrees of expression of PRX6 protein, which was localized mainly in the cytoplasm, were detected in adult and fetal normal esophageal tissues, precancerous lesions, and esophageal cancer. With the progression of esophageal lesions, PRX6 protein expression showed a declining trend(P < 0.05). In fetal epithelium from fetuses at gestational age 3-6 mo, PRX6 protein expression showed a declining trend with age(P < 0.05). PRX6 protein expression was significantly higher in well-differentiated esophageal cancer tissues than in poorly differentiated esophageal cancer tissues(P < 0.05).CONCLUSION Development and progression of esophageal cancer result from interactions of genetic changes(accumulation or superposition). PRX6 protein is associated with fetal esophageal development and cancer differentiation.展开更多
Background:Nuclear factor kappa B(NF-kappa B) overactivation plays a crucial role in T-helper 2 (Th2)-biased allergic airway inflammation by increased activation and decreased apoptosis of CD4(+) T cells. We have show...Background:Nuclear factor kappa B(NF-kappa B) overactivation plays a crucial role in T-helper 2 (Th2)-biased allergic airway inflammation by increased activation and decreased apoptosis of CD4(+) T cells. We have shown that targeted NF-kappa B suppression in dendritic cells by adenoviral gene transfer of a novel mutated inhibitor of NF-kappa B(I kappa B alpha) (AdI kappa B alpha M) contributes to T-cell tolerance, but the immunosuppressive action of AdI kappa B alpha M on memory(CD45RO(+)) CD4(+) T cells remains enigmatic. Methods:CD45RO(+) T cells from Dermatophagoides farinaei-sensitized asthmatic patients, untransfected or transfected with AdI kappa B alpha M or AdLacZ(beta-galactosidase) for 24 h, were stimulated with anti-CD3(1.0 mu g/ml) plus anti-CD28(0.5 mu g/ml) monoclonal antibody for an additional 24 h. I kappa B alpha M transgene expression and NF-kappa B activation were detected by polymerase chain reaction(PCR), reverse transcription-PCR(RT-PCR), Western blot analysis, and electrophoretic mobility shift assay. Phenotype and apoptosis were measured by flow cytometry, annexin V binding, and terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling analyses. Cytokine production and cell proliferation were determined using enzyme-linked immunosorbent assay andH-3 thymidine incorporation. Results:A unique 801-bp I kappa B alpha M cDNA and a dose-dependent increase in I kappa B alpha M transgene expression were observed in AdI kappa B alpha M-transfected CD45RO(+) T cells. Significantly, AdI kappa B alpha M inhibited CD3/CD28-mediated NF-kappa B activation in CD45RO(+) T cells, leading to evident apoptosis, reduction of eotaxin, RANTES, Th1 interferon (IFN)-gamma and interleukin (IL)-2, and Th2 (IL-4, IL-5, and IL-13 despite a slight decrease in IL-10) cytokines and secondary proliferative response. AdI kappa B alpha M also upregulated cytotoxic T lymphocyte-associated antigen 4(CTLA-4) and downregulated CD69 besides no change in CD28. Conclusion:I kappa B alpha M might be beneficial to augment memory CD4(+) T-cell tolerance through modulating B7-CD28/CTLA-4 co-stimulatory pathways and NF-kappa B-dependent cytokine profiles in allergic inflammatory diseases including asthma.展开更多
Four 20-membered N_2S_4-monoazathiacrown ethers have been synthesized and explored as neutral ionophores for Ag^+-selective electrodes.Potentiometric responses reveal that the flexibility of the ligands has great effe...Four 20-membered N_2S_4-monoazathiacrown ethers have been synthesized and explored as neutral ionophores for Ag^+-selective electrodes.Potentiometric responses reveal that the flexibility of the ligands has great effect on the selectivity and sensitivity to Ag^+ ions.The electrode based on ionophore 9,10,20,25-tetrahydro-5H,12H-tribenzo[b,n,r][1,7,10,16,4,13]tetrathiadiaza cycloicosine 6,13-(7H,14H)-dione(C) with 2-nitrophenyl octyl ether(o-NPOE) as solvent in a poly(vinyl chloride)(PVC) membrane matrix sho...展开更多
A large amount of nicotinamide adenine dinucleotide phosphate(NADPH) is required for fatty acid synthesis and maintenance of the redox state in cancer cells.Malic enzyme 1(ME1)-dependent NADPH production is one of the...A large amount of nicotinamide adenine dinucleotide phosphate(NADPH) is required for fatty acid synthesis and maintenance of the redox state in cancer cells.Malic enzyme 1(ME1)-dependent NADPH production is one of the three pathways that contribute to the formation of the cytosolic NADPH pool.ME1 is generally considered to be overexpressed in cancer cells to meet the high demand for increased de novo fatty acid synthesis.In the present study,we found that glucose induced higher ME1 activity and that repressing ME1 had a profound impact on glucose metabolism of nasopharyngeal carcinoma(NPC) cells.High incorporation of glucose and an enhancement of the pentose phosphate pathway were observed in ME1-repressed cells.However,there were no obvious changes in the other two pathways for glucose metabolism:glycolysis and oxidative phosphorylation.Interestingly,NADPH was decreased under low-glucose condition in ME1-repressed cells relative to wild-type cells,whereas no significant difference was observed under high-glucose condition.ME1-repressed cells had significantly decreased tolerance to low-glucose condition.Moreover,NADPH produced by ME1 was not only important for fatty acid synthesis but also essential for maintenance of the intracellular redox state and the protection of cells from oxidative stress.Furthermore,diminished migration and invasion were observed in ME1-repressed cells due to a reduced level of Snail protein.Collectively,these results suggest an essential role for ME1 in the production of cytosolic NADPH and maintenance of migratory and invasive abilities of NPC cells.展开更多
BACKGROUND: The anti-proliferative gene, PC3 (pheochromocytoma cell 3)/BTG2 (B-cell translocation gene 2), is one of the early growth response genes and belongs to the BTG/Tob protein family. This study aimed to asses...BACKGROUND: The anti-proliferative gene, PC3 (pheochromocytoma cell 3)/BTG2 (B-cell translocation gene 2), is one of the early growth response genes and belongs to the BTG/Tob protein family. This study aimed to assess the effects of recombinant human hepatopoietin (HPO) and partial hepatectomy on rapidly induced expression of immediate-early genes and to investigate the expression of PC3/BTG2 mRNA in hepatocellular carcinoma (HCC) at different stages of progression. METHODS: After a rat model of partial hepatectomy was established, we investigated gene expression within I hour after 2/3 partial hepatectomy by representational difference analysis and in a primary cultured hepatocyte system. The expression levels of PC3/BTG2 from liver tissues of the rat model were assessed by RT-PCR and Northern blotting. Meanwhile, the expression of BTG2 mRNA in a tissue microarray of HCC was determined by in situ hybridization. RESULTS: The PC3/BTG2 gene was rapidly induced after 2/3 partial hepatectomy and its expression peaked within 1-2 hours after operation. HPO rapidly induced the expression of the genes c-fos, LRF-1, and PC3 in primary cultured rat hepatocytes, which might be one of the molecular mechanisms by which HPO stimulates hepatocyte proliferation. Positive BTG2 mRNA expression was detected in 71.19% (42/59) of the HCC samples and in 75% (3/4) of the normal liver tissue samples obtained from the region around the HCC tissues. PC3/BTG2 mRNA was located mainly in the cytoplasm of HCC cells and its expression was related to the degree of differentiation. CONCLUSIONS: Recombinant human HPO and partial hepatectomy rapidly induce the expression of the PC3/BTG2 gene. PC3/BTG2 mRNA is highly expressed in HCC cells and its expression is related to the degree of cell differentiation. The abnormal expression of PC3/BTG2 is closely related to the genesis and development of HCC, so PC3/BTG2 may play an important role in these processes. (Hepatobilimy Pancreat Dis Int 2009; 8: 288-293)展开更多
BACKGROUND: Hepatocellular carcinoma (HCC) is characterized by multicause, obvious multistage and multifocal processes of tumor progression. The development of HCC is related intimately to overexpression and signal tr...BACKGROUND: Hepatocellular carcinoma (HCC) is characterized by multicause, obvious multistage and multifocal processes of tumor progression. The development of HCC is related intimately to overexpression and signal transduction of many cellular factors. This study was undertaken to investigate the dynamic expression and alteration of heat shock protein (HSP) gp96 along with its gene during HCC development. METHODS: A rat model of hepatoma induced with 2-fluorenylacetamide (2-FAA, 0.05%) was established in male Sprague-Dawley rats. Total RNA and pathological changes were observed during hepatocarcinogenesis. Total RNAs were transcribed into cDNA by reverse transcription and the gene fragment of gp96 was amplified by nested RT-PCR. The gp96 expression in rat liver tissues was semi-quantitatively analyzed by immunohistochemistry. RESULTS: Histological examination suggested that hepatocytes in rats fed with 2-FAA showed vacuole-like denaturation at the early stages, then dysplastic nodules appeared at the middle stage, and finally progressed to tubercles of cancerous nests. A tendency of increasing liver gp96 protein level was found from normal liver to precancerous to cancerous tissues during hepatoma development (P<0.01), and was in accordance with the changes in gp96 mRNA (P<0.05). CONCLUSION: HSP gp96 is involved in HCC development and its overexpression may be a useful marker for early diagnosis.展开更多
Tertiary lymphoid structures(TLSs)are ectopic immune cell aggregations that develop in peripheral tissues in response to a wide range of chronic inflammatory conditions,including infection,autoimmune disease,and cance...Tertiary lymphoid structures(TLSs)are ectopic immune cell aggregations that develop in peripheral tissues in response to a wide range of chronic inflammatory conditions,including infection,autoimmune disease,and cancer.In the tumor microenvironment(TME),the structures of TLSs,including B-cell-and T-cell-enriched areas indicate that the TLSs might be the local site during the initiation and maintenance of humoral and cellular immune responses against cancers.Numerous studies have evaluated the expression of TLSs in different cancer patients and their association with prognoses of cancer patients.It was shown that welldeveloped TLSs characterized by mature B cells synthesized tumor specific antibodies,which were considered as specific markers for a good prognosis.However,there are still some immunosuppressive factors existing in the TLSs that may affect anti-tumor responses.These factors include dysfunctional B cells,regulatory T cells,and T follicular regulatory cells.The complexity and heterogeneity of the TLS composition may affect the function and activity of TLSs;it is therefore essential to fully understand the function and influencing factors in TLSs.It has been reported that checkpoint inhibitors and vaccines are currently being developed to reprogram the TME by establishing mature TLSs to improve cancer immunotherapies.In this review,we focused on recent advances in TLSs in human solid tumors,including structural characteristics and classes,antitumor mechanisms,immunosuppressive factors,and TLSbased therapeutic approaches.展开更多
The compound traditional Chinese medicine Qingkailing, which is an ingredient used to treat cerebral ischemia, has been limited to studies concerning single genes or single pathways. Interactions and pharmacological m...The compound traditional Chinese medicine Qingkailing, which is an ingredient used to treat cerebral ischemia, has been limited to studies concerning single genes or single pathways. Interactions and pharmacological mechanisms of the compound ingredients （baicalin and jasminoidin） remain poorly understood. In the present study, baicalin and jasminoidin, as well as the combination, were used to separately treat mouse models of cerebral ischemia, cDNA microarray analyses of 374 cerebral ischemia-related genes were utilized to determine changes in gene-expression profiles. Arraytrack 3.40 and Ingenuity Pathway Analysis （IPA） databases were utilized to analyze changes in gene molecular functions and network path functions. Baicalin or jasminoidin alone effectively reduced infarct area, and the combination resulted in significantly better outcomes. IPA showed inhibited cell apoptosis in the baicalin group and Ca^2＋ channel regulation in the jasminoidin group. The combination of baicalin and jasminoidin activated HTR3A and F5 expression, regulated Ca^2＋ channels, activated kappa light polypeptide gene enhancer inhibitor IKBKG in B cells to control IkB kinase/nuclear factor-kB cascade, suppressed activation of inflammatory cytokine interleukin-6 receptors and activated transduction of guanine-nucleotide- binding protein （G protein） signal. Results suggested that the combination of baicalin and jasminoidin resulted in similar molecular mechanisms to baicalin and jasminoidin alone. However, novel pharmacological actions of compatibility were detected, demonstrating significant protection against cerebral ischemia.展开更多
In this paper, a concept of surface nanocrystallization (SNC) of metallic materials is introduced. Three types of SNC processes are classified. Different SNC mechanisms and possible techniques for SNC are discussed wi...In this paper, a concept of surface nanocrystallization (SNC) of metallic materials is introduced. Three types of SNC processes are classified. Different SNC mechanisms and possible techniques for SNC are discussed with emphasis on mechanically induced surface self-nanocrystallization. Further development and prospects are addressed with respect to the properties and behaviors of the materials with a nanocrystalline surface. Enhancement of the behavior of the engineering materials by means of the SNC technology and its industrial application possibilities are analyzed.展开更多
Understanding how evolutionary pressures related to climate change have shaped the current genetic background of domestic animals is a fundamental pursuit of biology. Here, we generated wholegenome sequencing data fro...Understanding how evolutionary pressures related to climate change have shaped the current genetic background of domestic animals is a fundamental pursuit of biology. Here, we generated wholegenome sequencing data from native goat populations in Iraq and Pakistan. Combined with previously published data on modern, ancient(Late Neolithic to Medieval periods), and wild Capra species worldwide, we explored the genetic population structure, ancestry components, and signatures of natural positive selection in native goat populations in Southwest Asia(SWA). Results revealed that the genetic structure of SWA goats was deeply influenced by gene flow from the eastern Mediterranean during the Chalcolithic period, which may reflect adaptation to gradual warming and aridity in the region. Furthermore, comparative genomic analysis revealed adaptive introgression of the KITLG locus from the Nubian ibex(C. nubiana) into African and SWA goats. The frequency of the selected allele at this locus was significantly higher among goat populations located near northeastern Africa. These results provide new insights into the genetic composition and history of goat populations in the SWA region.展开更多
Since the late 1950’s, the Malaysian human population has nearly quadrupled, increasing pressure on natural resource exploitation to meet domestic needs and to earn foreign exchange from exports. Global demand for Ma...Since the late 1950’s, the Malaysian human population has nearly quadrupled, increasing pressure on natural resource exploitation to meet domestic needs and to earn foreign exchange from exports. Global demand for Malaysian palm oil in particular had steeply increased since the mid-1970s and by 2013, the commodity was the leading foreign exchange earner. To fulfill and sustain this demand, the country’s economy has steadily shifted bias towards production and associated value addition of palm oil products for export. However, as a consequence, many of Malaysia’s natural tropical forests have been converted to palm oil farming resulting in loss of approximately 10,000 km2 of forest cover over the past twenty-five years, and biodiversity has been displaced or lost. To provide a deeper insight into the interplay amongst key interrelated environmental and socio-economic variables, and a forecast of possible future balance, we used a systems dynamism modeling tool, STELLAR (structural thinking, experiential learning laboratory with animation), to simulate and project how Malaysia could achieve a medium-term sustainable balance or optimization between palm oil production and forest conservation without compromising on human social welfare. The model consisted of four main modules (environmental, economic, social development and human welfare) each with component parameters, and interconnected by input and output loops. Model calibrations, testing and preruns involved existing official 30-year time-series datasets. Subsequently, four scenarios: Environmental conservation;Economic growth under increased global palm oil demand;Economy decline under decreased palm oil demand;and Control condition with little or no change, were selected for simulated projections of future possibilities. Simulation results showed that scenarios and variable interactions that reduce environmental damage would offer the best chance for optimizing the palm oil economy while also minimizing forest loss and promoting citizen social welfare.展开更多
A novel carbazole-based compound 5,3,6-bis[(N-ethylcarbazole-3-yl)-propene-1-keto]-N-ethylcarbazole has been designed, synthesized and characterized.The absorption and fluorescence spectra in solvents of different pol...A novel carbazole-based compound 5,3,6-bis[(N-ethylcarbazole-3-yl)-propene-1-keto]-N-ethylcarbazole has been designed, synthesized and characterized.The absorption and fluorescence spectra in solvents of different polarities prove that the compound has a distinct intramolecular charge transfer character.Compound 5 can be used as a new class of fluorescent probe or biosensor due to its sensitivity to the local microenvironment such as solvent polarity.展开更多
The interaction mechanism between human serum albumin(HSA) and 1-phenyl-3(fluorenone-2-yl)-5-(9-ethylcarbazole-3-yl)-2- pyrazoline(PFEP) was investigated by fluorescence and absorption titration techniques in combinat...The interaction mechanism between human serum albumin(HSA) and 1-phenyl-3(fluorenone-2-yl)-5-(9-ethylcarbazole-3-yl)-2- pyrazoline(PFEP) was investigated by fluorescence and absorption titration techniques in combination with molecular modeling method.Stern-Volmer plots at different temperatures proved that PFEP could quench the intrinsic fluorescence of HSA attributed to a static quenching procedure.The association constants were calculated in the range of 1×10~5-8×10~5mol^(-1) at different pH conditions,a...展开更多
Metal-enhanced room temperature phosphorescence of diiodofluorescein was first observed on filter paper surface.The phosphorescence intensity is 2.5-fold brighter from diiodofluorescein on silver nanoparticles-deposit...Metal-enhanced room temperature phosphorescence of diiodofluorescein was first observed on filter paper surface.The phosphorescence intensity is 2.5-fold brighter from diiodofluorescein on silver nanoparticles-deposited filter paper as compared with an identical control sample without silver nanoparticles.Furthermore,enhanced absorption was also observed for the same system.Our findings suggest that both singlet and triplet states can couple to surface plasmons and enhance phosphorescence quantum yields at ...展开更多
OBJECTIVE Hepatocellular carcinoma(HCC)is the fifth most common malignancy worldwide and the third cause of global cancer mortality.Activation of signal transducer and activator of transcription 3(STAT3)is commonly ob...OBJECTIVE Hepatocellular carcinoma(HCC)is the fifth most common malignancy worldwide and the third cause of global cancer mortality.Activation of signal transducer and activator of transcription 3(STAT3)is commonly observed in tumor cells and is a critical mediator of on cogenic signaling in HCC and controls the expression of several genes involved in proliferation,survival,metastasis and angiogenesis.Current drug-targeted therapies,besides being expensive,are associated with serious side effects and morbidity.Thus,novel agents that can suppress STAT3 activation have potential for both prevention and treatment of HCC.In the present report,we investigated whether the potent HAT/KAT inhibitor,garcinol,(apolyisoprenylatedbenzophenone),could suppress STAT3 activation in HCC cells and in nude mice model.METHODS The effect of garcinol on HCC cell lines wasdetermined by MTT assay,immunoblotting,DNA binding assays,immuno-fluorescenceand immune-histochemical analysis.The effect of garcinolon the inhibition of tumor growth in vivo was also investigated using HCCxenograft tumor modelin athymic nu/nu mice.RESULTS We found that garcinol could inhibit constitutive STAT3 activation in a dose-and time-dependent manner both by inhibiting STAT3 phosphorylation and acetylation in HCC cells.When investigated for molecular mechanism(s),we found that garcinol interferes with the dimer formation of STAT3 thereby inhibits its nuclear localization.Computational modeling showed that garcinol could bind to the SH2 domain of STAT3 and suppresses its dimerization in vitro.To understand the cellular mechanism(s)of inhibition of STAT3 function by garcinol,we observed that upon inhibition of STAT3 dimerization bygarcinol,STAT3 DNA binding ability gets repressed.The inhibition of STAT3 activation by garcinol led to the suppression of various gene products involved in proliferation,survival,and angiogenesis.Finally,when administered i.p.,garcinol inhibited the growth of human HCC xenograft tumors in athymic nu/nu mice.CONCLUSION Results frominvitroand in vivo studies suggest that garcinol exerts its anti-proliferative and pro-apoptotic effects through suppression of STAT3 signaling cascade in HCC by inhibiting its phosphorylation,acetylation and ultimately dimerization.展开更多
基金support from the National Natural Science Foundation of China(Grant Nos.52301137,51974097,52364050)the Natural Science Special Foundation of Guizhou University(No.(2023)20)+1 种基金Guizhou Province Science and Technology Project(Grant Nos.[2023]001,[2019]2163)Guiyang city Science and Technology Project(Grant No.[2023]48-16).
文摘The dynamic mechanical response and deformation mechanism of magnesium-yttrium alloy at high strain rate were investigated using split-Hopkinson pressure bar(SHPB)impact,and the microstructure evolution and crack formation mechanism were revealed.The yield strength and work hardening rate increase significantly with increasing impact strain rate.Deformation twinning and non-basal dislocation slip are the primary deformation mechanisms during testing.Contrary to crack initiation mechanism facilitated by adiabatic shear bands,we find that high-density co-axial nanocrystalline grains form near cracks,which leads to local softening and promotes crack initiation and rapid propagation.Most grains have similar<1^(-)21^(-)0>orientations,with unique misorientation of 24°,32°,62°,78°and 90°between adjacent grains,suggesting that these grains are primarily formed by interface transformation,which exhibits distinct differences from recrystallized grains.Our results shed light upon the dynamic mechanical response and crack formation mechanism in magnesium alloys under impact deformation.
文摘Developing efficient photocatalysts to address collaborative energy and environmental crises still faces significant challenges.In this report,we present a highly efficient MXene–based photocatalyst,which is combined with MoS_(2)nano patches and TiO_(2)/Ti_(3)C_(2)(TTC)nanowires through hydrothermal treatment.Of all the composites tested,the optimized photocatalyst gave a remarkable H_(2)and revolving polylactic acid(PLA)into pyruvic acid(PA).Achieving a remarkable H_(2)evolution rate of 637.1 and 243.2μmol g^(−1)h^(−1),in the presence of TEOA and PLA as a sacrificial reagent under UV-vis(λ≥365 nm)light irradiation.The improved photocatalytic activity is a result of the combination of dual cocatalyst on the surface of TTC photocatalyst,which create an ideal synergistic effect for the generation of PA and the production of H_(2)simultaneously.The MoS_(2)TiO_(2)/Ti_(3)C_(2)(MTT)composite can generate more photoexcited charge carriers,leading to the generation of more active radicals,which may enhance the system's photocatalytic activity.This work aims at demonstrating its future significance and guide the scientific community towards a more efficient approach to commercializing H_(2)through photocatalysis.
基金supported by grants from the Project of Elitist Peak in Six Fields(No.2006-B-063)the Projectof Medical Sciences(H200727),the Bureau of Health,Jiangsu Province,China
文摘BACKGROUND: Hepatocellular carcinoma (HCC) is one of the most common malignant tumors. We analyzed the expression of miclear-transcription factor-kappa B (NF-kappa B) during hepatocarcinogenesis in order to evaluate its dynamic expression and its clinical value in the development and diagnosis of HCC. METHODS: Hepatoma models were induced by oral administration of 2-acetamidoflurene (2-FAA) to male Sprague-Dawley rats. Morphological changes were observed after hematoxylin and eosin staining. The cellular distribution of NF-kappa B expression during different stages of cancer development was investigated by immunohistochemistry, and the level of NF-kappa B expression in liver tissues was quantitatively analyzed by ELISA. The gene fragments of hepatic NF-kappa B were amplified by nested-polymerase chain reaction assay. RESULTS: Hepatocytes showed vacuole-like degeneration during the early stages, then had a hyperplastic nodal appearance during the middle stages, and finally progressed to tubercles of cancerous nests with high differentiation. The NF-kappa B-positive material was buff-colored, fine particles localized in the nucleus, and the incidence of NF-kappa B-positive cells was 81.8% in degeneration, 83.3% in precancerous lesions, and 100% in cancerous tissues. All of these values were higher than those in controls (P<0.01). Hepatic NF-kappa B expression and hepatic NF-kappa B-mRNA were also higher during the course of HCC development (P<0.01). CONCLUSION: The NF-kappa B signal transduction pathway is activated during the early stages of HCC development, and its abnormal expression may be associated with the occurrence of HCC.
基金the National Natural Science Foundation of China.
文摘Based on the minimum principle of acceleration in the elastic-plastic continua under finite def ormation, the dynamic response of an elastic-perfectly plastic pin-ended beam subjected to rectangular impulse loading is studied with the help of a numerical approach. The calculated results once again show the anomalous behavior of the beam during its response process, which was previously found in [1]. By carefully analyzing the instantaneous distribution of the bending moment, the membrane force, the curvature and displacement during the response process, it is concluded that the interactive effect between the geometry and materials nonlinearities of the structure is the key reason for leading to the anomalous behavior. This will be helpful for clarifying some misunderstandings in explaining the problem before.
文摘BACKGROUND: Recent studies have confirmed that the expression of Ezrin, hepatocyte growth factor (HGF) and its receptor (C-met) is related to the genesis, progress, invasion and metastasis of some malignant tumors. Researches have also found that the biological function of Ezrin is closely related to HGF/C-met in malignant tumors. However, there is no report on the expression levels of Ezrin, HGF and C-met in rat pancreatic cancer induced by dimethylbenzanthracene (DMBA). This study aimed to detect the expression of Ezrin, HGF and C-met in rat pancreatic cancer and non-cancerous pancreatic tissues, and assess its effect in cancer induction by DMBA. METHODS: Ninety Sprague-Dawley rats were divided into 3 groups randomly: 40 in a pancreatic cancer model group (group A), 40 in a trichostatin A (TSA) intervention group (group B), and 10 in a control group (group C). DMBA was directly implanted into the parenchyma of rat pancreas in group A+group B. The rats of group B were treated with 1 ml of TSA saline solution (1 mu g/ml) via intraperitoneal injection weekly. The carcinogenesis of rats executed within 3-5 months in groups A and B was observed by macrograph and microscopy. Meanwhile, the rats in group C were executed within 5 months. The EnVision (TM) immunohistochemistry for detecting the expression levels of Ezrin, HGF and C-met was used in paraffin-embedded sections of the pancreatic specimens. RESULTS: The incidence of pancreatic cancer in group A was 48.6% and in group B 33.3%. The maximal diameter of tumor mass was significantly larger in group A than that in group B (P<0.05). No pathological changes were observed in the pancreas of group C and other main organs of groups A and B. The positive rates of Ezrin, HGF and C-met were significantly higher in ductal adenocarcinoma than in non-cancerous pancreatic tissues of groups A and B (P<0.01). The positive rates of Ezrin, HGF and C-met were significantly higher in ductal adenocarcinoma of group A than those in non-cancerous pancreatic tissues of group A (P<0.05), but there was no significant difference in group B (P>0.05). The positive rates of Ezrin, HGF and C-met in non-cancerous pancreatic tissues proved mild to severe atypical hyperplasia of the ductal epithelia. The pancreas of group C and 2 cases of fibrosarcoma showed the negative expression of Ezrin, HGF and C-met. There was a trend of consistency in the expression of Ezrin, HGF and C-met in ductal adenocarcinoma (P<0.05 or P<0.01). CONCLUSIONS: DMBA directly implanted into the parenchyma of the pancreas can produce a model of pancreatic cancer with a high incidence in a short time. TSA might inhibit the carcinogenesis and growth of pancreatic cancer, and its effects may be related to the inhibition of the expression of Ezrin, HGF and C-met during the process. Ezrin, HGF and C-met may have positive effects on the carcinogenesis of rat pancreas. (Hepatobiliary Pancreat Dis Int 2010; 9: 639-644)
基金Supported by National Natural Science Foundation of Chinathe Guangdong Provincial People’s Government of the Joint Natural Science Fund,U1301227Major Project of Science and Technology of Henan Province,161100311300
文摘AIM To understand the molecular mechanism of esophageal cancer development and provide molecular markers for screening high-risk populations and early diagnosis. METHODS Two-dimensional electrophoresis combined with mass spectrometry were adopted to screen differentially expressed proteins in nine cases of fetal esophageal epithelium, eight cases of esophageal cancer, and eight cases of tumor-adjacent normal esophageal epithelium collected from fetuses of different gestational age, or esophageal cancer patients from a high-risk area of esophageal cancer in China. Immunohistochemistry(avidin-biotin-horseradish peroxidase complex method) was used to detect the expression of peroxiredoxin(PRX)6 in 91 cases of esophageal cancer, tumoradjacent normal esophageal tissue, basal cell hyperplasia, dysplasia, and carcinoma in situ, as well as 65 cases of esophageal epithelium from fetuses at a gestational age of 3-9 mo.RESULTS After peptide mass fingerprint analysis and search of protein databases, 21 differential proteins were identified; some of which represent a protein isoform. Varying degrees of expression of PRX6 protein, which was localized mainly in the cytoplasm, were detected in adult and fetal normal esophageal tissues, precancerous lesions, and esophageal cancer. With the progression of esophageal lesions, PRX6 protein expression showed a declining trend(P < 0.05). In fetal epithelium from fetuses at gestational age 3-6 mo, PRX6 protein expression showed a declining trend with age(P < 0.05). PRX6 protein expression was significantly higher in well-differentiated esophageal cancer tissues than in poorly differentiated esophageal cancer tissues(P < 0.05).CONCLUSION Development and progression of esophageal cancer result from interactions of genetic changes(accumulation or superposition). PRX6 protein is associated with fetal esophageal development and cancer differentiation.
文摘Background:Nuclear factor kappa B(NF-kappa B) overactivation plays a crucial role in T-helper 2 (Th2)-biased allergic airway inflammation by increased activation and decreased apoptosis of CD4(+) T cells. We have shown that targeted NF-kappa B suppression in dendritic cells by adenoviral gene transfer of a novel mutated inhibitor of NF-kappa B(I kappa B alpha) (AdI kappa B alpha M) contributes to T-cell tolerance, but the immunosuppressive action of AdI kappa B alpha M on memory(CD45RO(+)) CD4(+) T cells remains enigmatic. Methods:CD45RO(+) T cells from Dermatophagoides farinaei-sensitized asthmatic patients, untransfected or transfected with AdI kappa B alpha M or AdLacZ(beta-galactosidase) for 24 h, were stimulated with anti-CD3(1.0 mu g/ml) plus anti-CD28(0.5 mu g/ml) monoclonal antibody for an additional 24 h. I kappa B alpha M transgene expression and NF-kappa B activation were detected by polymerase chain reaction(PCR), reverse transcription-PCR(RT-PCR), Western blot analysis, and electrophoretic mobility shift assay. Phenotype and apoptosis were measured by flow cytometry, annexin V binding, and terminal deoxyribonucleotidyl transferase-mediated dUTP nick end labeling analyses. Cytokine production and cell proliferation were determined using enzyme-linked immunosorbent assay andH-3 thymidine incorporation. Results:A unique 801-bp I kappa B alpha M cDNA and a dose-dependent increase in I kappa B alpha M transgene expression were observed in AdI kappa B alpha M-transfected CD45RO(+) T cells. Significantly, AdI kappa B alpha M inhibited CD3/CD28-mediated NF-kappa B activation in CD45RO(+) T cells, leading to evident apoptosis, reduction of eotaxin, RANTES, Th1 interferon (IFN)-gamma and interleukin (IL)-2, and Th2 (IL-4, IL-5, and IL-13 despite a slight decrease in IL-10) cytokines and secondary proliferative response. AdI kappa B alpha M also upregulated cytotoxic T lymphocyte-associated antigen 4(CTLA-4) and downregulated CD69 besides no change in CD28. Conclusion:I kappa B alpha M might be beneficial to augment memory CD4(+) T-cell tolerance through modulating B7-CD28/CTLA-4 co-stimulatory pathways and NF-kappa B-dependent cytokine profiles in allergic inflammatory diseases including asthma.
基金supported by the Chinese Academy of Sciences(No.KZCX2-YW-410)the National Natural Science Foundation of China(No.40776058)+1 种基金the National 863 High Technology Project of the Ministry of Science and Technology of China(No.2007AA09Z103)the Outstanding Youth Natural Science Foundation of Shandong Province(No.JQ200814)
文摘Four 20-membered N_2S_4-monoazathiacrown ethers have been synthesized and explored as neutral ionophores for Ag^+-selective electrodes.Potentiometric responses reveal that the flexibility of the ligands has great effect on the selectivity and sensitivity to Ag^+ ions.The electrode based on ionophore 9,10,20,25-tetrahydro-5H,12H-tribenzo[b,n,r][1,7,10,16,4,13]tetrathiadiaza cycloicosine 6,13-(7H,14H)-dione(C) with 2-nitrophenyl octyl ether(o-NPOE) as solvent in a poly(vinyl chloride)(PVC) membrane matrix sho...
基金supported by grants from the Major State Basic Research Program (973 Project) of China(No.2006CB910104 and 2010CB912201)the National High Technology Research and Development Program of China (863 Program) (No.20060102A4002)+1 种基金the State Key Program of National Natural Science Foundation of China (No.81030043)the Guangdong Province-National Natural Science Foundation of China Cooperation Program (No.u0732005)
文摘A large amount of nicotinamide adenine dinucleotide phosphate(NADPH) is required for fatty acid synthesis and maintenance of the redox state in cancer cells.Malic enzyme 1(ME1)-dependent NADPH production is one of the three pathways that contribute to the formation of the cytosolic NADPH pool.ME1 is generally considered to be overexpressed in cancer cells to meet the high demand for increased de novo fatty acid synthesis.In the present study,we found that glucose induced higher ME1 activity and that repressing ME1 had a profound impact on glucose metabolism of nasopharyngeal carcinoma(NPC) cells.High incorporation of glucose and an enhancement of the pentose phosphate pathway were observed in ME1-repressed cells.However,there were no obvious changes in the other two pathways for glucose metabolism:glycolysis and oxidative phosphorylation.Interestingly,NADPH was decreased under low-glucose condition in ME1-repressed cells relative to wild-type cells,whereas no significant difference was observed under high-glucose condition.ME1-repressed cells had significantly decreased tolerance to low-glucose condition.Moreover,NADPH produced by ME1 was not only important for fatty acid synthesis but also essential for maintenance of the intracellular redox state and the protection of cells from oxidative stress.Furthermore,diminished migration and invasion were observed in ME1-repressed cells due to a reduced level of Snail protein.Collectively,these results suggest an essential role for ME1 in the production of cytosolic NADPH and maintenance of migratory and invasive abilities of NPC cells.
基金supported by grants from the National Natural Science Foundation of China(Nos.30370341and 30570410)the Academic Foundation for Author of National Excellent Doctoral Dissertation of China(No.200261).
文摘BACKGROUND: The anti-proliferative gene, PC3 (pheochromocytoma cell 3)/BTG2 (B-cell translocation gene 2), is one of the early growth response genes and belongs to the BTG/Tob protein family. This study aimed to assess the effects of recombinant human hepatopoietin (HPO) and partial hepatectomy on rapidly induced expression of immediate-early genes and to investigate the expression of PC3/BTG2 mRNA in hepatocellular carcinoma (HCC) at different stages of progression. METHODS: After a rat model of partial hepatectomy was established, we investigated gene expression within I hour after 2/3 partial hepatectomy by representational difference analysis and in a primary cultured hepatocyte system. The expression levels of PC3/BTG2 from liver tissues of the rat model were assessed by RT-PCR and Northern blotting. Meanwhile, the expression of BTG2 mRNA in a tissue microarray of HCC was determined by in situ hybridization. RESULTS: The PC3/BTG2 gene was rapidly induced after 2/3 partial hepatectomy and its expression peaked within 1-2 hours after operation. HPO rapidly induced the expression of the genes c-fos, LRF-1, and PC3 in primary cultured rat hepatocytes, which might be one of the molecular mechanisms by which HPO stimulates hepatocyte proliferation. Positive BTG2 mRNA expression was detected in 71.19% (42/59) of the HCC samples and in 75% (3/4) of the normal liver tissue samples obtained from the region around the HCC tissues. PC3/BTG2 mRNA was located mainly in the cytoplasm of HCC cells and its expression was related to the degree of differentiation. CONCLUSIONS: Recombinant human HPO and partial hepatectomy rapidly induce the expression of the PC3/BTG2 gene. PC3/BTG2 mRNA is highly expressed in HCC cells and its expression is related to the degree of cell differentiation. The abnormal expression of PC3/BTG2 is closely related to the genesis and development of HCC, so PC3/BTG2 may play an important role in these processes. (Hepatobilimy Pancreat Dis Int 2009; 8: 288-293)
基金The study was supported by grants-in-aid from the Key Project of Medical Science of Jiangsu Province, China (RC2003100)the Science and Technology Project for Social Development of Nantong, China (No. S40034).
文摘BACKGROUND: Hepatocellular carcinoma (HCC) is characterized by multicause, obvious multistage and multifocal processes of tumor progression. The development of HCC is related intimately to overexpression and signal transduction of many cellular factors. This study was undertaken to investigate the dynamic expression and alteration of heat shock protein (HSP) gp96 along with its gene during HCC development. METHODS: A rat model of hepatoma induced with 2-fluorenylacetamide (2-FAA, 0.05%) was established in male Sprague-Dawley rats. Total RNA and pathological changes were observed during hepatocarcinogenesis. Total RNAs were transcribed into cDNA by reverse transcription and the gene fragment of gp96 was amplified by nested RT-PCR. The gp96 expression in rat liver tissues was semi-quantitatively analyzed by immunohistochemistry. RESULTS: Histological examination suggested that hepatocytes in rats fed with 2-FAA showed vacuole-like denaturation at the early stages, then dysplastic nodules appeared at the middle stage, and finally progressed to tubercles of cancerous nests. A tendency of increasing liver gp96 protein level was found from normal liver to precancerous to cancerous tissues during hepatoma development (P<0.01), and was in accordance with the changes in gp96 mRNA (P<0.05). CONCLUSION: HSP gp96 is involved in HCC development and its overexpression may be a useful marker for early diagnosis.
基金This study was supported by grants from the National Key R&D Program of China(Grant No.2018YFC1313400)the National Natural Science Foundation of China(Grant No.U20A20375).
文摘Tertiary lymphoid structures(TLSs)are ectopic immune cell aggregations that develop in peripheral tissues in response to a wide range of chronic inflammatory conditions,including infection,autoimmune disease,and cancer.In the tumor microenvironment(TME),the structures of TLSs,including B-cell-and T-cell-enriched areas indicate that the TLSs might be the local site during the initiation and maintenance of humoral and cellular immune responses against cancers.Numerous studies have evaluated the expression of TLSs in different cancer patients and their association with prognoses of cancer patients.It was shown that welldeveloped TLSs characterized by mature B cells synthesized tumor specific antibodies,which were considered as specific markers for a good prognosis.However,there are still some immunosuppressive factors existing in the TLSs that may affect anti-tumor responses.These factors include dysfunctional B cells,regulatory T cells,and T follicular regulatory cells.The complexity and heterogeneity of the TLS composition may affect the function and activity of TLSs;it is therefore essential to fully understand the function and influencing factors in TLSs.It has been reported that checkpoint inhibitors and vaccines are currently being developed to reprogram the TME by establishing mature TLSs to improve cancer immunotherapies.In this review,we focused on recent advances in TLSs in human solid tumors,including structural characteristics and classes,antitumor mechanisms,immunosuppressive factors,and TLSbased therapeutic approaches.
基金the Postdoctoral Science Foundation of China,No.20090450553
文摘The compound traditional Chinese medicine Qingkailing, which is an ingredient used to treat cerebral ischemia, has been limited to studies concerning single genes or single pathways. Interactions and pharmacological mechanisms of the compound ingredients （baicalin and jasminoidin） remain poorly understood. In the present study, baicalin and jasminoidin, as well as the combination, were used to separately treat mouse models of cerebral ischemia, cDNA microarray analyses of 374 cerebral ischemia-related genes were utilized to determine changes in gene-expression profiles. Arraytrack 3.40 and Ingenuity Pathway Analysis （IPA） databases were utilized to analyze changes in gene molecular functions and network path functions. Baicalin or jasminoidin alone effectively reduced infarct area, and the combination resulted in significantly better outcomes. IPA showed inhibited cell apoptosis in the baicalin group and Ca^2＋ channel regulation in the jasminoidin group. The combination of baicalin and jasminoidin activated HTR3A and F5 expression, regulated Ca^2＋ channels, activated kappa light polypeptide gene enhancer inhibitor IKBKG in B cells to control IkB kinase/nuclear factor-kB cascade, suppressed activation of inflammatory cytokine interleukin-6 receptors and activated transduction of guanine-nucleotide- binding protein （G protein） signal. Results suggested that the combination of baicalin and jasminoidin resulted in similar molecular mechanisms to baicalin and jasminoidin alone. However, novel pharmacological actions of compatibility were detected, demonstrating significant protection against cerebral ischemia.
文摘In this paper, a concept of surface nanocrystallization (SNC) of metallic materials is introduced. Three types of SNC processes are classified. Different SNC mechanisms and possible techniques for SNC are discussed with emphasis on mechanically induced surface self-nanocrystallization. Further development and prospects are addressed with respect to the properties and behaviors of the materials with a nanocrystalline surface. Enhancement of the behavior of the engineering materials by means of the SNC technology and its industrial application possibilities are analyzed.
基金supported by the National Natural Science Foundation of China(32050410304,32002140,31822052,91431572381)National Thousand Youth Talents Plan to Y.J。
文摘Understanding how evolutionary pressures related to climate change have shaped the current genetic background of domestic animals is a fundamental pursuit of biology. Here, we generated wholegenome sequencing data from native goat populations in Iraq and Pakistan. Combined with previously published data on modern, ancient(Late Neolithic to Medieval periods), and wild Capra species worldwide, we explored the genetic population structure, ancestry components, and signatures of natural positive selection in native goat populations in Southwest Asia(SWA). Results revealed that the genetic structure of SWA goats was deeply influenced by gene flow from the eastern Mediterranean during the Chalcolithic period, which may reflect adaptation to gradual warming and aridity in the region. Furthermore, comparative genomic analysis revealed adaptive introgression of the KITLG locus from the Nubian ibex(C. nubiana) into African and SWA goats. The frequency of the selected allele at this locus was significantly higher among goat populations located near northeastern Africa. These results provide new insights into the genetic composition and history of goat populations in the SWA region.
文摘Since the late 1950’s, the Malaysian human population has nearly quadrupled, increasing pressure on natural resource exploitation to meet domestic needs and to earn foreign exchange from exports. Global demand for Malaysian palm oil in particular had steeply increased since the mid-1970s and by 2013, the commodity was the leading foreign exchange earner. To fulfill and sustain this demand, the country’s economy has steadily shifted bias towards production and associated value addition of palm oil products for export. However, as a consequence, many of Malaysia’s natural tropical forests have been converted to palm oil farming resulting in loss of approximately 10,000 km2 of forest cover over the past twenty-five years, and biodiversity has been displaced or lost. To provide a deeper insight into the interplay amongst key interrelated environmental and socio-economic variables, and a forecast of possible future balance, we used a systems dynamism modeling tool, STELLAR (structural thinking, experiential learning laboratory with animation), to simulate and project how Malaysia could achieve a medium-term sustainable balance or optimization between palm oil production and forest conservation without compromising on human social welfare. The model consisted of four main modules (environmental, economic, social development and human welfare) each with component parameters, and interconnected by input and output loops. Model calibrations, testing and preruns involved existing official 30-year time-series datasets. Subsequently, four scenarios: Environmental conservation;Economic growth under increased global palm oil demand;Economy decline under decreased palm oil demand;and Control condition with little or no change, were selected for simulated projections of future possibilities. Simulation results showed that scenarios and variable interactions that reduce environmental damage would offer the best chance for optimizing the palm oil economy while also minimizing forest loss and promoting citizen social welfare.
基金supported by the National Science Foundation of China(No.20875059)the Youth Science Foundation of Shanxi Province(No.20051005).
文摘A novel carbazole-based compound 5,3,6-bis[(N-ethylcarbazole-3-yl)-propene-1-keto]-N-ethylcarbazole has been designed, synthesized and characterized.The absorption and fluorescence spectra in solvents of different polarities prove that the compound has a distinct intramolecular charge transfer character.Compound 5 can be used as a new class of fluorescent probe or biosensor due to its sensitivity to the local microenvironment such as solvent polarity.
基金supported by the National Natural Science Foundation of China(No.20875059)
文摘The interaction mechanism between human serum albumin(HSA) and 1-phenyl-3(fluorenone-2-yl)-5-(9-ethylcarbazole-3-yl)-2- pyrazoline(PFEP) was investigated by fluorescence and absorption titration techniques in combination with molecular modeling method.Stern-Volmer plots at different temperatures proved that PFEP could quench the intrinsic fluorescence of HSA attributed to a static quenching procedure.The association constants were calculated in the range of 1×10~5-8×10~5mol^(-1) at different pH conditions,a...
基金supported by the National Science Foundation of China(No.20777062).
文摘Metal-enhanced room temperature phosphorescence of diiodofluorescein was first observed on filter paper surface.The phosphorescence intensity is 2.5-fold brighter from diiodofluorescein on silver nanoparticles-deposited filter paper as compared with an identical control sample without silver nanoparticles.Furthermore,enhanced absorption was also observed for the same system.Our findings suggest that both singlet and triplet states can couple to surface plasmons and enhance phosphorescence quantum yields at ...
基金The project supported in part by agrant from National Medical Research Council of Singapore
文摘OBJECTIVE Hepatocellular carcinoma(HCC)is the fifth most common malignancy worldwide and the third cause of global cancer mortality.Activation of signal transducer and activator of transcription 3(STAT3)is commonly observed in tumor cells and is a critical mediator of on cogenic signaling in HCC and controls the expression of several genes involved in proliferation,survival,metastasis and angiogenesis.Current drug-targeted therapies,besides being expensive,are associated with serious side effects and morbidity.Thus,novel agents that can suppress STAT3 activation have potential for both prevention and treatment of HCC.In the present report,we investigated whether the potent HAT/KAT inhibitor,garcinol,(apolyisoprenylatedbenzophenone),could suppress STAT3 activation in HCC cells and in nude mice model.METHODS The effect of garcinol on HCC cell lines wasdetermined by MTT assay,immunoblotting,DNA binding assays,immuno-fluorescenceand immune-histochemical analysis.The effect of garcinolon the inhibition of tumor growth in vivo was also investigated using HCCxenograft tumor modelin athymic nu/nu mice.RESULTS We found that garcinol could inhibit constitutive STAT3 activation in a dose-and time-dependent manner both by inhibiting STAT3 phosphorylation and acetylation in HCC cells.When investigated for molecular mechanism(s),we found that garcinol interferes with the dimer formation of STAT3 thereby inhibits its nuclear localization.Computational modeling showed that garcinol could bind to the SH2 domain of STAT3 and suppresses its dimerization in vitro.To understand the cellular mechanism(s)of inhibition of STAT3 function by garcinol,we observed that upon inhibition of STAT3 dimerization bygarcinol,STAT3 DNA binding ability gets repressed.The inhibition of STAT3 activation by garcinol led to the suppression of various gene products involved in proliferation,survival,and angiogenesis.Finally,when administered i.p.,garcinol inhibited the growth of human HCC xenograft tumors in athymic nu/nu mice.CONCLUSION Results frominvitroand in vivo studies suggest that garcinol exerts its anti-proliferative and pro-apoptotic effects through suppression of STAT3 signaling cascade in HCC by inhibiting its phosphorylation,acetylation and ultimately dimerization.
