Scratch Method Research Articles

Development of Antimicrobial Conjugates and Evaluating its Antibacterial potential and Wound Healing ability

Antimicrobial peptides from Streptomyces sp. and marine fish (Carangoides malabaricus) were extracted and developed as conjugates in the present study. The objective was framed to analyze the ability of conjugate to retard the growth of test bacteria causing diabetic foot ulcers. Fibroblast cell adhesion on AMP conjugates coated mesh samples were recorded using microscopic studies with an aim of developing a novel tissue engineered wound dressing material. Thus developed tissue engineered materials were evaluated for its antibacterial potential against wound pathogens; and to assay the wound healing ability using a standard in vitro wound scratch method. Tissue engineered materials were developed using L929 fibroblast cells. L929 fibroblast cells attachment and its stage wise development on wound dressing mesh materials were microscopically observed. In vitro wound healing assay revealed that the developed conjugates (containing AMPs) exhibited cell migration and proliferation after 12th hour of incubation indicating the wound healing abilities. The results showed that the developed tissue engineered wound dressing material has commercial interest in near future.

Copper-based tungsten coating by CVD: Microstructure, thermal shock resistance and interfacial bond force

Tungsten coating was fabricated on a pure copper substrate by chemical vapor deposition technique (CVD). The deposition rate was about 0.6 mm/h, and the average thickness of the W coating is197.3 μm. The thermal shock resistance of tungsten coating was investigated by thermal shock test, and the interface bonding force was characterized by scratch method. Experimental results show that the coating sample has good thermal shock resistance at 500 °C, and the W coating could sustain thermal shock 50 cycles at 1000 °C without visible failure. According to the scratch test results, it can be found that the effect of thermal shock frequency on the bonding force was obvious. After 10 thermal shocks, the interface bonding strength does not decrease significantly, but it decreases sharply after 30 thermal shocks at different temperatures.

A study of mechanical and tribological properties as well as wear performance of a multifunctional bilayer AlTiN PVD coating during the ultra-high-speed turning of 304 austenitic stainless steel

In this study, a novel bi-layer AlTiN PVD coating was deposited on a tungsten carbide substrate. The bi-layer coating, with a total thickness of 3.5 μm consists of a 1.0 μm Al60Ti40N top layer and a 2.5 μm Al50Ti50N sublayer. Monolayer Al60Ti40N and Al50Ti50N coatings (each around 3.5 μm) were used as benchmarks. All the studied coatings were deposited by an industrial cathodic arc PVD coater. The ultra-high-speed finish turning of austenitic stainless steel 304 (SS304) was performed under a cutting speed of 420 m/min. The coatings' mechanical properties (hardness, elastic modulus, toughness, and adhesion) were evaluated using nano-indentation and scratch methods. The obtained data illustrated the influence of the mechanical properties of the coatings on tool wear performance. Cutting tests showed that the longest tool life was achieved by the bi-layer coated tool. Wear morphology studies had revealed that a combination of oxidation/diffusion wear mechanisms resulted in cratering whereas abrasion/attrition led to flank wear. An investigation of tribological characteristics had shown that the bi-layer coated tool produced improved chips. This indicates an optimal frictional condition at the cutting zone. Finally, a chip cross-section analysis was performed to verify the microstructure variations and work-hardening effect in the chips.

Leukemia- Derived Exosomes Activate Migration and Tumor-Associated Genes in Astrocytes Isolated from Human Brain Tissue

Background: In children with lymphoblastic leukemia (ALL), cancerous metastasis to the central nervous system (CNS) is common, but there is insufficient information on this metastasis and cancer progression process. Further, the role of exosomes on cancer growth and metastasis has been the attention of many studies. Because the astrocytes involve in the blood-brain barrier and stay in contact with peripheral blood , we investigated the effect of exosomes derived Nalm6 cell line on astrocytes from human brain fetal tissue. Methods: In this in vitro study, exosomes were isolated from the supernatant of Nalm6 cell line by centrifugation and identified by DLS, AFM and FE-SEM methods. Astrocytes were isolated from human fetal brain tissue cells and expanded and identified by GFAP antibody with immunocytochemistry. Astrocytes were treated with different concentrations of exosomes (i.e., 5, 10, 30, and 50 µg/ml),. Proliferation and migration were assessed with Trypan blue staining and scratch methods, respectively. To define tumorogensis changes in astrocytes treated by exosomes, the expression of MMP9, P53, and Cox2 genes were investigated by Real-Time PCR.Findings: According to the DLS results, the size of exosomes was about 43 nm. AFM and FE-SEM imaging indicated these exosomes have a spherical shape. Our results showed that the proliferation of astrocytes significantly increased when treated with 50 µg/ml of exosomes.Therefore, the concentration of 50 µg/ml was considered for further experiments. Astrocyte migration was significantly increased compared to the control group. Finally, our results showed tumorogenesis changes in astrocytes by increasing the expression of MMP9 and Cox2 and decreasing the expression of p53 at mRNA level.Conclusion: Based on our in vitro study, exosomes derived from ALL as a peripheral tumor can change the behavior of astrocytes as a target for metastasis. Further investigations on this topic are warranted to shed light on metastatic mechanisms.

Development of Antimicrobial Conjugates and Evaluating its Antibacterial potential and Wound Healing ability

Antimicrobial peptides from Streptomyces sp. and marine fish (Carangoides malabaricus) were extracted and developed as conjugates in the present study. The objective was framed to analyze the ability of conjugate to retard the growth of test bacteria causing diabetic foot ulcers. Fibroblast cell adhesion on AMP conjugates coated mesh samples were recorded using microscopic studies with an aim of developing a novel tissue engineered wound dressing material. Thus developed tissue engineered materials were evaluated for its antibacterial potential against wound pathogens; and to assay the wound healing ability using a standard in vitro wound scratch method. Tissue engineered materials were developed using L929 fibroblast cells. L929 fibroblast cells attachment and its stage wise development on wound dressing mesh materials were microscopically observed. In vitro wound healing assay revealed that the developed conjugates (containing AMPs) exhibited cell migration and proliferation after 12th hour of incubation indicating the wound healing abilities. The results showed that the developed tissue engineered wound dressing material has commercial interest in near future.

Friction and Wear Behavior of a Physical Vapor Deposition Coating Studied Using a Micro-Scratch Technique

Abstract CrSiN coating was deposited by physical vapor deposition (PVD) magnetron sputtering on XC100 steel substrate. Microstructural and morphological properties were studied using scanning electron microscopy (SEM)/energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and atomic force microscopy (AFM). Nanoindentation and scratching experiments were conducted to study the mechanical and adhesion behavior. Multi-pass scratch tests were conducted under different sliding conditions. Results showed that CrSiN coating has a dense and compact nanocomposite microstructure consisting of CrN nanocrystallites and SiN amorphous matrix. The CrSiN thin film exhibit hardness and Young's modulus of 30.52 ± 1.85 GPa and 338.32 ± 13.5 GPa, respectively. The H/E, H3/E2, and 1/HE2 ratios were also calculated (H/E ≈ 0.09, H3/E2 ≈ 0.024, and 1/HE2 ≈ 2.86 × 10−07) and used to predict and assess the elastic/plastic and wear resistance. Critical loads LC1, LC2, and LC3 obtained with scratch test, were, respectively, 11.5 ± 0.12, 16.6 ± 0.23, and 20 ± 0.35 N. Multi-pass scratch were analyzed and the friction coefficient (COF), the damage mechanism, and wear volume were determined. The use of an energetic approach allowed to determine the energetic wear coefficient. CrSiN coating revealed a low friction coefficient (around 0.1) and a low energetic wear coefficient (6.3 × 10−7 mm3/N.m). In addition, it was found that multi-pass scratch method has the potential to extract relevant information about wear behavior.

Nanoscale characteristics of conditioning film development on photobioreactor materials: influence on the initial adhesion and biofilm formation by a cyanobacterium

Adsorption of conditioning films on a solid surface is the first step in the development of biofilms. With the goal of understanding the preliminary adhesion mechanisms of cyanobacteria on photobioreactor (PBR) materials to prevent biofouling, the physical changes occurring on PBR materials were investigated during the initial adhesion and biofilm formation by Anabaena sp. PCC 7120, a cyanobacterium that is genetically modified to produce linalool. Atomic force microscopy (AFM) revealed that the conditioning film deposition was in the form of spike-like structures on all the materials except PVC. The average heights (in the range 9 − 16 nm) of the conditioning films deposited on glass, PMMA, PC and HDPE were 11 to 20 times higher than on PVC at 96 h. The time dependent change in thickness of conditioning films correlated well with Anabaena cell attachment to the PBR materials. The rapid and significant colonization of Anabaena on glass within 48 h was consistent with the increase in thickness of the conditioning film within this time period. Lack of the conditioning film spike structures and no change in thickness of the conditioning films with time on the PVC together with comparatively delayed cell attachment and conditioning-film protein deposition on this material, indicated that the nanoscale spike structures on the other PBR materials may be accelerating the cell attachment process but are not a prerequisite for cell attachment. These results suggest that PVC should be explored further as an antifouling material for photobioreactors. The thickness of the conditioning films on glass measured by a scratch and scan method was in good agreement with the thickness values measured by an adhesive tape method, indicating that both these methods can be used for fast and reliable AFM thickness determination of bacterial conditioning films.

Shear fracture performance of the interface between ultra-high toughness cementitious composites and reactive powder concrete

This study used unnotched compression tests and digital image correlation technology to analyze the influence of two different casting intervals and three different roughness conditions on the fracture toughness of the interfaces between ultra-high toughness cementitious composite (UHTCC) and reactive powder concrete (RPC). UHTCC exhibits pseudo-strain-hardening responses and multi-cracking behaviors, and the most notable characteristic of RPC is its dense microstructure. The results show that the complete interfacial shear fracture process included three stages: crack initiation, steady crack propagation and unsteady crack propagation. A double-K crack propagation criterion for interfacial shear fracture of composite structures was proposed by introducing two parameters: initial and unstable fracture toughness. After introducing interfacial roughness via the scratch method, the unstable fracture toughness decreased. The 24-h casting interval group had a lower initial fracture toughness and higher unstable fracture toughness than the 2-h group. The unstable fracture toughness of all the composite specimens exceeded that of C60 concrete, indicating that they had excellent resistance to interfacial shear fracture.

Identification of plant growth promoting rhizobacteria in rhizosphere of bamboo thorns with gram methylene blue and lugol staining

Plant Growth Promoting Rhizobacteria is a group of mirorooganisms that can increase plant growth and yield through reactions that occur in the soil, however, the large number of microorganisms contained in the PGPR rhizosphere of bamboo thorns makes it difficult to know which bacteria are the most dominant and most active in influencing plants. Generally, gram staining of bacteria aims to facilitate the observation of bacterial morphology with the aid of a microscope. Bacteria are generally colorless and almost invisible due to the lack of contrast with the water in which they may be present. Staining using methylene blue and lugol is generally needed to see the bacteria clearly. This study aims to determine the effect of using the gram stain test method with methylene blue and lugol in identifying PGPR bacteria from rhizosphere of bamboo thorn. This research was conducted at the Laboratory of Biological Fertilizers and Potential Microbes, Faculty of Agriculture, Hasanuddin University in October-December 2019. The research methods included the manufacture of microorganism planting media, pouring media, planting bacteria using the scatter and scratch method, and the gram reaction test using methylene blue and lugol. The results obtained showed that the use of the gram test with methylene blue and lugol resulted in a blue color which indicated the dominance of the genus Pseudomonas, while the pink/purple color indicated the dominance of the genus Bacillus. Changes in the color of the bacteria to pink/dark purple, the bacteria were gram negative and belong to the Pseudomonas group and there was a change in blue, so the bacteria were gram-positive and were group of Bacillus. Therefore, the use of the gram test with methylene blue and lugol has an optimal effect in detecting microorganisms especially in identifying PGPR.

Biochemical characteristics and antibiotic resistance of bacterial isolate from Ctenocephalides felis

Cats are the most domesticated animals kept by humans in the world. Cat fleas are ectoparasites that have the potential to transmit disease caused by microbes in humans. Biochemical identification research and antibiotic resistance tests have been carried out against bacterial isolates from cat fleas. Cat fleas were isolated from cats in Manado City, North Sulawesi, Indonesia. Isolation of bacteria was conducted using the scratch method on nutrient agar media. The pure bacterial culture is then used for biochemical analysis and antibiotic resistance testing. Biochemical analysis and resistance tests were performed using the Vitec 2 Compact instrument with a standardized automatic analysis model. The results obtained three species of bacteria from cat fleas based on biochemical identification, namely S. equorum, C. freundii, and Pantoea spp. Antibiotic resistance test on S. equorum showed that of the 60 types of antibiotics used, 55 were sensitive and 7 were resistant. Furthermore, C. freundii, of the 18 types of drugs, 7 were sensitive and 11 were resistant. Meanwhile, in Pantoea spp., Sensitive and resistant drugs were not found. However, the results of this study prove that bacteria from cat fleas have the potential to infect humans with relatively high antibiotic resistance.

Multi-tip indenter tool scratch behavior of glass-ceramics

To reduce the surface flaws and subsurface damages of glass-ceramics as clinical substitute and repair materials, it is necessary to clarify the material removal behaviors and crack propagation modes in the grinding process. In this paper, a multi-tip indenter tool was fabricated and assembled on a Nanomechanical testing system. The experiments of ramp load scratching with the single-tip/multi-tip indenter tools were conducted on glass-ceramics to compare the material removal behavior under different scratch methods. The surface morphology, subsurface cracks propagation, and the brittle-ductile transition region were observed and investigated. Based on the scratch experiments, the finite element simulation model was established to analyze the stress characteristics in the glass-ceramics. The result shows that in multi-tip scratches, as the depth of scratch increases, the growth of surface cracks mainly takes three forms. Compared with non-instant multi-scratch, instant multi-scratch makes the propagation path of lateral cracks closer to specimen surface, suppresses the propagation severity of lateral and median cracks, and increases the depth of brittle-ductile transition region. This paper's results provide a fundamental understanding of multiple abrasive grains instant interaction on the material removal mechanism, and help to improve the clinical performance of glass-ceramics as biomedical materials.

Resveratrol loaded self-nanoemulsifying drug delivery system (SNEDDS) for pancreatic cancer: Formulation design, optimization and in vitro evaluation

Pancreatic cancers are mostly inoperable and have a low survival rate. Nanomedicine has provided some promise in overcoming some major hurdles in pancreatic cancer. Meanwhile, resveratrol (RESV) has been reported to be useful in pancreatic cancer therapeutics. Therefore, the purpose of the study was to develop SNEDDS formulation of RESV for therapeutic application in pancreatic cancer therapy. Capryol 90, Cremophor RH, and Transcutol P were selected as the oil, surfactant, and co-surfactant respectively after preliminary studies. From the pseudo-ternary phase diagram, the surfactant:co-surfactant mixture (Smix) ratio of 3:1 was found to be most suitable for the formulation of SNEDDS. A central composite rotatable design (CCRD) was employed for studying the effect of volumes of oil and Smix on PS and PDI of globules formed from the SNEDDS. For this purpose, the Oil:Smix ratio of 1:4 was chosen for the central point in the design. The results of CCRD showed that a higher volume of oils results in a higher PS and PDI. Similarly, a higher volume of Smix resulted in a lower PS and PDI. The SNEDDS formulation for characterization was chosen based on the particle size (PS), polydispersity index (PDI), and thermodynamic stability. The TEM images revealed uniformity in size and morphology of the formed droplets. Meanwhile, the in vitro RESV release was rapid from RESV-SNEDDS. The cell viability studies, change in mitochondrial membrane potential (MMP), COX-2 and NF-kB levels, and the wound scratch method showed enhanced cytotoxicity of RESV-SNEDDS compared to RESV alone. Overall, the formulation of RESV into SNEDSS was proved to be a promising approach for overcoming the therapeutic hindrances related to pancreatic cancer.

Casein kinase 1 (CK1) promotes the proliferation and metastasis of glioma cells via the phosphatidylinositol 3 kinase-matrix metalloproteinase 2 (AKT-MMP2) pathway.

BackgroundGlioma is a type of tumor that usually occurs in the adult central nervous system. Protein kinases have become important targets for oncotherapy since they are closely correlated with signal transduction. The role of the casein kinase 1 (CK1) gene in glioma remains to be fully elucidated.MethodsThe mRNA and protein expression of CK1 were analyzed by Realtime PCR, Western blot and immunohistochemistry. The cell behavior was assayed by MTT, Transwell and cell scratch methods. Cell cycle and cell apoptosis were performed by flow cytometer. Construction of stable cell line was completed by lentivirus infection. The nude mouse model was used for in vivo analysis on the role of CK1 by injecting the cells into subcutaneous tissue, tail vein and cerebral cortex. The prognostic role of CK1 in glioma was evaluated using Kaplan-Meier and Cox regression analyses.Resultsimmunohistochemical staining demonstrated that the expression of CK1 in glioma samples was correlated with the grade of glioma. Survival analysis using Kaplan-Meier and multivariate analysis by Cox regression indicated that CK1 could be used as an independent prognostic marker for glioma. The methyl thiazolyl tetrazolium (MTT), transwell, and cell scratch assays demonstrated that the CK1 gene promoted cell proliferation and invasion through the phosphatidylinositol 3 kinase/matrix metalloproteinase 2 (AKT-MMP2) signaling pathway. In vivo experiments in mice also confirmed the ability of CK1 to enhance tumor proliferation and metastasis, with the metastatic site being the small intestine.Conclusionsthe expression of CK1 was correlated with glioma grade and patient survival and it may enhance glioma proliferation and metastasis via AKT-MMP2 pathway.

Anti-Helicobacter pylori Effects of Propolis Ethanol Extract on Clarithromycin and Metronidazole Resistant Strains

Antimicrobial resistance for Helicobacter pylori infection still become problem in Indonesia especially for metronidazole and clarithromycin resistance that is commonly used in the national regiment therapy. Finding a new antimicrobial agent against this bacterium is still a challenge to face. Propolis extract is well known substance which has antimicrobial effect against some gram-negative bacteria. However, the effect against H. pylori remain unknown. We analysed the antimicrobial effect of propolis extract against H. pylori in clarithromycin and metronidazole Resistant Strains. Anti-H. pylori effect of ethanol propolis extract was tested on 10 types of H. pylori strains isolated from dyspeptic patients in Indonesia. Ethanol propolis extracts (PRO) show inhibitory activity at concentrations of 5% and 10% on all strains H. pylori. Determination minimum inhibitory concentration (MIC) value of propolis extract used microdilution method, the MIC values were in the range of 1024-8192 µg/mL. Determination of the minimum bactericidal concentration (MBC) value is performed by scratch method based on the results of the microdilution test and produces an MBC value in the range of 1024 - 16348 µg/mL. The required concentration of propolis extract for the bactericidal effect against H. pylori was the same or eight-fold higher than the corresponding value. The combination of propolis extract and metronidazole based through paper tape method showed an additive effect, as well as the combination of propolis extract and clarithromycin. This extract might be can become alternative treatment against H. pylori infection that resistance for metronidazole and clarithromycin treatment

Nanoindentation Hardness and Practical Scratch Resistance in Mechanically Tunable Anti-Reflection Coatings

This work presents fundamental understanding of the correlation between nanoindentation hardness and practical scratch resistance for mechanically tunable anti-reflective (AR) hardcoatings. These coatings exhibit a unique design freedom, allowing quasi-continuous variation in the thickness of a central hardcoat layer in the multilayer design, with minimal impact on anti-reflective optical performance. This allows detailed study of anti-reflection coating durability based on variations in hardness vs. depth profiles, without the durability results being confounded by variations in optics. Finite element modeling is shown to be a useful tool for the design and analysis of hardness vs. depth profiles in these multilayer films. Using samples fabricated by reactive sputtering, nanoindentation hardness depth profiles were correlated with practical scratch resistance using three different scratch and abrasion test methods, simulating real world scratch events. Scratch depths from these experiments are shown to correlate to scratches observed in the field from consumer electronics devices with chemically strengthened glass covers. For high practical scratch resistance, coating designs with hardness >15 GPa maintained over depths of 200–800 nm were found to be particularly excellent, which is a substantially greater depth of high hardness than can be achieved using previously common AR coating designs.

Evaluation and analysis of commercial cultivars and elite breeding lines for resistance to the bacterial blight pathogen race 18 in cotton

Cotton (Gossypium spp.) is an economically important crop which provides a significant source of fiber, animal feed, and food oil worldwide. Bacterial blight (BB), caused by Xanthomonas citri pv. malvacearum (Xcm), infects the aerial part of the cotton plant at all stages and can cause a significant loss in yield and fiber quality. In this study, 288 Upland (G. hirsutum) and 8 Pima (G. barbadense) commercial transgenic cultivars and elite breeding lines were divided into 10 replicated tests and evaluated for BB resistance using the toothpick scratching method in the greenhouse in 2016–2017. Five Upland and four Pima genotypes were used as resistant and susceptible controls, respectively. The percentage of susceptible plants with water-soaking symptoms was calculated on a replication basis for each genotype. While all the commercial Pima cultivars tested were susceptible, 21 commercial Upland cultivars were resistant to Xcm race 18. A total of 22 elite public breeding lines were resistant, including 11 lines from the University of Arkansas with an active breeding program for BB resistance and 1–4 resistant lines from five other public breeding programs without an active screening component for BB resistance. Of more than 150 breeding lines developed at New Mexico State University, 11 were found to be resistant to BB. Many commercial cultivars and public breeding lines were found to contain various levels of susceptible plants and are therefore heterogeneous in BB resistance. The results suggest that the resistance to Xcm race 18 can be easily bred in breeding without a selection pressure. A pedigree analysis showed that there are likely different sources of BB resistance. The resistant cultivars and lines identified should be a valuable resource to improve BB resistance in cotton breeding.

Children’s Packaging Between Interactive and Sustainability

The research includes a discussion about the concept of sustainability in the interactive design of children's packaging, to give additional value to promote reusable packaging and functional diversity through the application of interactive packaging methods To develop the child's cognitive and creative abilities, one of the child's mental needs is research and exploration, and this is done by expanding the child's environment and using environmental materials in the child's tools and toys. And these methods can be applied on pharmaceutical or food packaging for children, one of the kind of interactive methods that can be applied is playing method, which is represented in the construction and planning games, collection and classification games, analysis and interpretation games, technical games such as drawing and coloring. And the technical method such as the method of scratching (removing some parts of the design) or using the raised and embossed surfaces or the paper folding method (origami). In addition to the ability to apply the QR code to link packaging with the advertisement for the wrapped product to anchor the product in the child's mind, and increase marketing activity. The concept of sustainability is one of the most important things in the field of packaging today to reduce the accumulation of waste through recycling or reuse and reduce the use of raw materials. In this regard, this study is based on an overview of importance of various interactive packaging methods and expanding the role of packaging to be better suited for children.

Identification of potential candidate proteins for reprogramming spinal cord-derived astrocytes into neurons: a proteomic analysis.

Our previous study has confirmed that astrocytes overexpressing neurogenic differentiation factor 1 (NEUROD1) in the spinal cord can be reprogrammed into neurons under in vivo conditions. However, whether they can also be reprogrammed into neurons under in vitro conditions remains unclear, and the mechanisms of programmed conversion from astrocytes to neurons have not yet been clarified. In the present study, we prepared reactive astrocytes from newborn rat spinal cord astrocytes using the scratch method and infected them with lentivirus carrying NEUROD1. The results showed that NEUROD1 overexpression reprogrammed the cultured reactive astrocytes into neurons in vitro with an efficiency of 13.4%. Using proteomic and bioinformatic analyses, 1952 proteins were identified, of which 92 were differentially expressed. Among these proteins, 11 were identified as candidate proteins in the process of reprogramming based on their biological functions and fold-changes in the bioinformatic analysis. Furthermore, western blot assay revealed that casein kinase II subunit alpha (CSNK2A2) and pinin (PNN) expression in NEUROD1-overexpressing reactive astrocytes was significantly increased, suggesting that NEUROD1 can directly reprogram spinal cord-derived reactive astrocytes into neurons in vitro, and that the NEUROD1-CSNK2A2-PNN pathway is involved in this process. This study was approved by the Animal Ethics Committee of Fujian Medical University, China (approval No. 2016-05) on April 18, 2016.

Multifunctional application of nanoscratch technique to characterize cementitious materials

This study aims to further explore the multifunctional applicability of nanoscratch technique to cementitious materials for comprehensive characterization. Based on the investigation of deformation, applied force, and fracture toughness of hardened cement paste during scratching, the methods of phase identification, fracture toughness of individual phase, and the interfacial transition zone (ITZ) thickness quantification were proposed and discussed. After redefining the vertical loading rate of scratching, the slope of the square scratching depth vs. scratching length is recognized as a reliable parameter to distinguish the individual phases for the first time. A fracture toughness-based method is proposed to quantify the thickness of ITZ between clinker and hydrates. Meanwhile, the applicability of phase identification by the scratch method is discussed for different transverse scratching speeds and the vertical loading rates. The findings will benefit the investigation and mechanism understanding of cementitious materials at the microscale by utilizing nanoscratch technique.

MiR-34a Reverses Doxorubicin Resistance in Breast Cancer

Chemotherapy is effectively used for treating breast cancer, but the problem of tumor resistance to chemotherapy drugs has been plaguing scientists. Our study investigated miR-34a?s effect on the sensitivity of drug-resistant strains to chemotherapeutic drugs using doxorubicin-resistant strains of breast cancer cells. Cell survival rate was detected by MTT assay. The doxorubicin-resistant strain rMCF-7 was obtained. The cell scratching method and CCK-8 method were used to detect cell migration and proliferation.Western Blot was performed for measuring SIRT1, p-AKT, AKT, p-mTOR and mTOR level. miR-34a significantly reduced the survival rate o doxorubicin-resistant breast cancer cell line rMCF-7 and significantly enhanced doxorubicin?s effect on inhibiting cell proliferation and cell migration. Compared with the doxorubicin group alone, miR-34a and doxorubicin combination group significantly downregulated SIRT1, p-AKT/AKT and p-mTOR/mTOR related proteins in rMCF-7 cells. miR-34a can reverse the resistance of doxorubicin in breast cancer in vitro and the mechanism may be through inhibition of SIRT and AKT signaling.