10 research outputs found
Structural lubricity under ambient conditions.
Despite its fundamental importance, physical mechanisms that govern friction are poorly understood. While a state of ultra-low friction, termed structural lubricity, is expected for any clean, atomically flat interface consisting of two different materials with incommensurate structures, some associated predictions could only be quantitatively confirmed under ultra-high vacuum (UHV) conditions so far. Here, we report structurally lubric sliding under ambient conditions at mesoscopic (∼4,000-130,000 nm(2)) interfaces formed by gold islands on graphite. Ab initio calculations reveal that the gold-graphite interface is expected to remain largely free from contaminant molecules, leading to structurally lubric sliding. The experiments reported here demonstrate the potential for practical lubrication schemes for micro- and nano-electromechanical systems, which would mainly rely on an atomic-scale structural mismatch between the slider and substrate components, via the utilization of material systems featuring clean, atomically flat interfaces under ambient conditions
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Structural lubricity under ambient conditions.
Despite its fundamental importance, physical mechanisms that govern friction are poorly understood. While a state of ultra-low friction, termed structural lubricity, is expected for any clean, atomically flat interface consisting of two different materials with incommensurate structures, some associated predictions could only be quantitatively confirmed under ultra-high vacuum (UHV) conditions so far. Here, we report structurally lubric sliding under ambient conditions at mesoscopic (∼4,000-130,000 nm(2)) interfaces formed by gold islands on graphite. Ab initio calculations reveal that the gold-graphite interface is expected to remain largely free from contaminant molecules, leading to structurally lubric sliding. The experiments reported here demonstrate the potential for practical lubrication schemes for micro- and nano-electromechanical systems, which would mainly rely on an atomic-scale structural mismatch between the slider and substrate components, via the utilization of material systems featuring clean, atomically flat interfaces under ambient conditions
Selective inhibition of carbonic anhydrase-IX by sulphonamide derivatives induces pH and reactive oxygen species-mediated apoptosis in cervical cancer HeLa cells
Selective inhibition with sulphonamides of carbonic anhydrase (CA) IX reduces cell proliferation and induces apoptosis in human cancer cells. The effect on CA IX expression of seven previously synthesised sulphonamide inhibitors, with high affinity for CA IX, as well as their effect on the proliferation/apoptosis of cancer/normal cell lines was investigated. Two normal and three human cancer cell lines were used. Treatment resulted in dose- and time-dependent inhibition of the growth of various cancer cell lines. One compound showed remarkably high toxicity towards CA IX-positive HeLa cells. The mechanisms of apoptosis induction were determined with Annexin-V and AO/EB staining, cleaved caspases (caspase-3, caspase-8, caspase-9) and cleaved PARP activation, reactive oxygen species production (ROS), mitochondrial membrane potential (MMP), intracellular pH (pHi), extracellular pH (pHe), lactate level and cell cycle analysis. The autophagy induction mechanisms were also investigated. The modulation of apoptotic and autophagic genes (Bax, Bcl-2, caspase-3, caspase-8, caspase-9, caspase-12, Beclin and LC3) was measured using real time PCR. The positive staining using γ-H2AX and AO/EB dye, showed increased cleaved caspase-3, caspase-8, caspase-9, increased ROS production, MMP and enhanced mRNA expression of apoptotic genes, suggesting that anticancer effects are also exerted through its apoptosis-inducing properties. Our results show that such sulphonamides might have the potential as new leads for detailed investigations against CA IX-positive cervical cancers
Inhibition of Carbonic Anhydrase IX Promotes Apoptosis through Intracellular pH Level Alterations in Cervical Cancer Cells
Carbonic anhydrase IX (CAIX) is a hypoxia-related protein that plays a role in proliferation in solid tumours. However, how CAIX increases proliferation and metastasis in solid tumours is unclear. The objective of this study was to investigate how a synthetic CAIX inhibitor triggers apoptosis in the HeLa cell line. The intracellular effects of CAIX inhibition were determined with AO/EB, AnnexinV-PI, and γ-H2AX staining; measurements of intracellular pH (pHi), reactive oxygen species (ROS), and mitochondrial membrane potential (MMP); and analyses of cell cycle, apoptotic, and autophagic modulator gene expression (Bax, Bcl-2, caspase-3, caspase-8, caspase-9, caspase-12, Beclin, and LC3), caspase protein level (pro-caspase 3 and cleaved caspase-3, -8, -9), cleaved PARP activation, and CAIX protein level. Sulphonamide CAIX inhibitor E showed the lowest IC50 and the highest selectivity index in CAIX-positive HeLa cells. CAIX inhibition changed the morphology of HeLa cells and increased the ratio of apoptotic cells, dramatically disturbing the homeostasis of intracellular pHi, MMP and ROS levels. All these phenomena consequent to CA IX inhibition triggered apoptosis and autophagy in HeLa cells. Taken together, these results further endorse the previous findings that CAIX inhibitors represent an important therapeutic strategy, which is worth pursuing in different cancer types, considering that presently only one sulphonamide inhibitor, SLC-0111, has arrived in Phase Ib/II clinical trials as an antitumour/antimetastatic drug
Prenatal distress levels of pregnant women in Turkey and affecting factors: a multicentre study
This study was conducted to determine prenatal distress levels of pregnant women from seven provinces of Turkey and factors affecting prenatal distress levels. The multicentre descriptive study included 2365 pregnant women who were in the twentieth gestational week and above. The data were collected using the pregnancy information form, prenatal distress questionnaire and spousal support scale. Descriptive statistics, Student'st-test, ANOVA and logistic regression were used to evaluate the data. The results of this study demonstrated that pregnant women's prenatal distress levels are affected by such factors as the region lived in, lack of spousal support and being a primary school graduate. Nurses should develop intervention strategies that involve the pregnant woman's spouse to reduce prenatal distress and the factors affecting prenatal distress.Impact statement What is already known on this subject?Prenatal distress can have significant effects on pregnancy, maternal health and human development across the lifespan. What the results of this study add?Spousal support could also have an effect on the psychological health of mothers. What the implications are of these findings for clinical practice and/or further research?Nurses and midwives monitor the pregnant women, and therefore, they should evaluate the prenatal distress levels in the prenatal period, plan intervention strategies for pregnant women with high stress levels and include the pregnant women's spouses in these intervention strategies
Burn reconstruction: Severe mentosternal adhesion
Burn injuries are severe traumatic events with a range of local and systemic repercussions. Various complications may occur in the early and late stages of burn injuries depending on the causative agent, duration of contact, degree of burn, and extent of the harm. Long after their burn scars have healed, many patients still struggle with issues related to their burn injuries. Burn scars, hypertrophic scars, keloid, contractures, heterotopic ossifications, chronic ulcerations, and marginal ulcers are late-onset complications that hurt the quality of life and result in lost productivity. Escharotomy, fasciotomy, repeated debridement, and primary wound management can lower mortality and potential complications. Complex burns should ideally be treated in specialized burn centers supervised by plastic surgeons and a multidisciplinary team of experts who treat patients holistically. This case report presents a contracture that occurred following an extensive burn to the neck, arm, and finger joints, which was successfully treated with surgery and healed without complications