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Cancer stem cells (CSCs) are inherently resistant to chemotherapy, and CSCs in chemotherapy-failed recurrent tumors are enriched; however, the cellular origin of chemotherapy-induced CSC enrichment remains unclear. Communication with stromal fibroblasts may induce cancer cell dedifferentiation into CSCs through secreted factors. We recently demonstrated that fibroblast-derived exosomes promote chemoresistance in colorectal cancer (CRC). Here, we report that fibroblasts confer CRC chemoresistance via exosome-induced reprogramming (dedifferentiation) of bulk CRC cells to phenotypic and functional CSCs. At the molecular level, we provided evidence that the major reprogramming regulators in fibroblast-exosomes are Wnts. Exosomal Wnts were found to increase Wnt activity and drug resistance in differentiated CRC cells, and inhibiting Wnt release diminished this effect in vitro and in vivo. Together, our results indicate that exosomal Wnts derived from fibroblasts could induce the dedifferentiation of cancer cells to promote chemoresistance in CRC, and suggest that interfering with exosomal Wnt signaling may help to improve chemosensitivity and the therapeutic window.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.An amendment to this paper has been published and can be accessed via a link at the top of the paper.

This article presents a study on the synthesis and character of a new organic-inorganic hybrid [4FBzTPP] 2 [CuBr 4 ] ( 1 ) ([4FBzTPP] + is 4-fluorobenzyltriphenylphosphinium) by XRD, SEM, FTIR and UV-Vis. The XRD analysis showed that the hybrid 1 belongs to the triclinic space group P 2 1 with b =  8.8600(10) Å, c =  16.4867(17) Å, α  =  16.639(2)°, β  =  96.342(4)°, V  = 2415.6(5) Å 3 , and Z  = 2. The hybrid consists of two [4FBzTPP] + cations and one [CuBr 4 ] 2– anion, and the [CuBr 4 ] 2– exhibits a twisted tetrahedral coordination geometry with the average bond length between Cu–Br is 2.393 Å. The 3D network structure of 1 is formed by electrostatic terms and other intermolecular interactions. The hybrid material undergoes a direct optical transition and has energy gap values of 1.66 eV and 2.18 eV, indicating its potential as a semiconductor material for optical research. The hybrid material undergoes a direct optical transition and has energy gap values of 1.66 eV and 2.18 eV, showing that the hybrid material is a potential semiconductor material for optical research. In addition, the compound exhibited good antibacterial activity against E. coli and S. aureus .

Corrosion behavior of friction stir welded 2195-T8 Al-Cu-Li alloy has been studied. Immersion and electrochemical open-circuit potential (OCP) test were applied. The microstructure and precipitates evolution in different zones were investigated by scanning electron microscopy, stereoscope, and transmission electron microscopy. The corrosion tests showed that the sequence of corrosion resistance of each area of the joint is: welding nugget zone (WNZ) > base metal > heat affected zone (HAZ). The WNZ showed highest corrosion resistance due to the fine recrystallized grains, the dissolution of T1(Al2CuLi) phase, and the refined and evenly-distributed particles in this area. However, the HAZ had the lowest corrosion resistance due to the intergranular precipitates, deleterious precipitate-free zone (PFZ), S′ (Al2CuMg) phase, and the galvanic corrosion couples formed among T1, θ′, and PFZ.

Background: A decrease in folic acid and subsequent DNA hypomethylation may be involved in gastric carcinogenesis. Epidemiological and nutritional studies have indicated that folate status modulates the risk of developing cancers. Aims: To investigate whether folic acid plays an important role in the chemoprevention of gastric carcinogenesis induced by N-ethyl-N-nitrosoguanidine (ENNG) in beagles. Methods: Sixteen male beagles were randomly divided into two groups: folic acid treated group and control group. In both groups beagles were fed ENNG 75 mg per day for eight months and in the treated group 20 mg folic acid was given to beagles for 15 months. Gastroscopy and biopsies were performed before and every 2–3 months after administration of ENNG until the end of the experiment. Histopathological lesions were diagnosed with regard to the criteria for human gastric mucosal biopsies. Serum and gastric mucosal tissue folic acid concentrations were measured. Results: In the control group, all beagles developed gastric cancer (8/8) compared with only 3/8 in the folic acid treated group (p<0.05). Moreover, serum and gastric mucosal tissue folic acid concentrations were markedly elevated 15 months after folic acid administration. The difference was statistically significant between the two groups (p<0.05). Conclusions: Our results indicate that high dose folic acid plays an important role in the chemoprevention of gastric carcinogenesis induced by a chemical carcinogen ENNG in beagles.

An important and often discussed research problem in statistics is how to compare several populations; examples arise in medical science, engineering, finance and other fields. Often population means or medians are compared. However, one population may have a higher mean income, for example, because of a small number of super-rich individuals; the mean therefore may not reflect the wealth of the general population. Instead, an index of the degree of stochastic dominance of one population over another would better reflect their relative wealth. Currently, we can estimate such an index under restrictive conditions, but there is no generic estimator with a known asymptotic distribution. In this paper, we suggest linking the populations via the density ratio model. Under this model, we develop an empirical likelihood estimator and establish its asymptotic normality. In addition, we improve the estimation efficiency by examining the similarities between the populations. Furthermore, we provide a valid bootstrap method for hypothesis testing and the construction of confidence intervals. Simulation experiments show that the proposed estimator substantially improves the estimation efficiency and power of the test, and leads to confidence intervals with satisfactorily precise coverage probabilities. It is also robust with respect to mild model misspecification. Two examples are given to demonstrate the usefulness of both the method and the concept.

The landfill leachate treated by sonication in presence of Fe(2+) (US/Fe(2+)) and then by photo-Fenton achieved the highest total organic carbon (TOC) removal efficiency among the screened processes. The lower initial pH, dosage of Fe(2+) and initial concentration of leachate were helpful in raising TOC removal efficiency of leachate by US/Fe(2+). The optimal conditions for the US-photo-Fenton process were as follows: initial pH at 3.0, [H2O2]/[TOC0] at 2, [H2O2]/[Fe(2+)] at 5 and initial concentration of landfill leachate at 600 mg/L. The removal efficiency of TOC, chemical oxygen demand (COD) and 5-day biochemical oxygen demand (BOD5) were 68.3, 79.6 and 58.2%, while the BOD5/COD rose from 0.20 to 0.43 at optimum condition. Based on gas chromatography-mass spectrometry (GC-MS) results, 36 of a total of 56 pollutants were completely degraded by US-photo-Fenton treatment.

The landfill leachate treated by sonication in presence of Fe2+ (US/Fe2+) and then by photo-Fenton achieved the highest total organic carbon (TOC) removal efficiency among the screened processes. The lower initial pH, dosage of Fe2+ and initial concentration of leachate were helpful in raising TOC removal efficiency of leachate by US/Fe2+. The optimal conditions for the US-photo-Fenton process were as follows: initial pH at 3.0, [H2O2]/[TOC0] at 2, [H2O2]/[Fe2+] at 5 and initial concentration of landfill leachate at 600 mg/L. The removal efficiency of TOC, chemical oxygen demand (COD) and 5-day biochemical oxygen demand (BOD5) were 68.3, 79.6 and 58.2%, while the BOD5/COD rose from 0.20 to 0.43 at optimum condition. Based on gas chromatography–mass spectrometry (GC-MS) results, 36 of a total of 56 pollutants were completely degraded by US-photo-Fenton treatment.

The present study is focused on the relation between the microscopic sinusoidal surface morphology and model-1 fracture toughness of carbon reinforced titanium laminates, based on cohesive elements. The interface toughness was computed as a function of geometric parameters of the interface texture. The results suggest that the toughness is increased when wavelength (λ) increase, which provides the need to design fracture failure resistance materials by carefully selecting the suitable parameters of the interface texture.

[This retracts the article DOI: 10.2147/OTT.S273614.].