Decoding Gobekli Tepe with archaeoastronomy: What does the fox say?

We have interpreted much of the symbolism of Göbekli Tepe in terms of astronomical events. By matching low-relief carvings on some of the pillars at Göbekli Tepe to star asterisms we find compelling evidence that the famous ‘Vulture Stone’ is a date stamp for 10950 BC ± 250 yrs, which corresponds closely to the proposed Younger Dryas event, estimated at 10890 BC. We also find evidence that a key function of Göbekli Tepe was to observe meteor showers and record cometary encounters. Indeed, the people of Göbekli Tepe appear to have had a special interest in the Taurid meteor stream, the same meteor stream that is proposed as responsible for the Younger-Dryas event. Is Göbekli Tepe the ‘smoking gun’ for the Younger-Dryas cometary encounter, and hence for coherent catastrophism

Label-free identification and characterization of living human primary and secondary tumour cells

Primary and secondary tumour cells exhibit biochemical differences (with Raman spectroscopy and imaging), and mechanical differences (with atomic force microscopy).</p

Fabrication and evaluation of poly(lactic acid), chitosan, and tricalcium phosphate biocomposites for guided bone regeneration

This study presents and evaluates an approach for fabricating poly(lactic acid) (PLA)/chitosan (CS)/tricalcium phosphate (TCP) electrospun scaffolds for guided bone regeneration, a dental procedure that uses membranes to direct and delineate regions of osteogenesis. Biomaterials were pre‐processed using cryomilling, a solid‐state grinding technique that facilitates the generation of powdered biocomposites conducive to electrospinning. X‐ray diffraction (XRD) confirmed the generation of cryomilled blends consisting of PLA, CS, and TCP. Results from the differential scanning calorimetry showed an upward shift in glass transition temperature and an increase in crystallinity with the inclusion of TCP reinforcing the observations from XRD. Murine macrophages were used to confirm the biocompatibility of the cryomilled powders and was evaluated using CellTiter‐Blue (CTB) cell viability assay and brightfield microscopy. Scanning electron microscopy was used to examine the morphology of the fibers produced via electrospinning, while Raman spectroscopy confirmed material homogeneity. In vitro studies with MG‐63 cells validated the capacity of composite scaffolds to encourage proliferation, while Coherent anti‐Stokes Raman scattering and fluorescence microscopies provided visual evidence of cell proliferation. CTB assay revealed that cells maintain viability and metabolic activity at 3 and 7 days after seeding, demonstrating the potential of the biocomposite membranes

Real-time and non-invasive measurements of cell mechanical behaviour with optical coherence phase microscopy

There is an unmet need in tissue engineering for non-invasive, label-free monitoring of cell mechanical behaviour in their physiological environment. Here, we describe a novel optical coherence phase microscopy (OCPM) set-up which can map relative cell mechanical behaviour in monolayers and 3D systems non-invasively, and in real-time. 3T3 and MCF-7 cells were investigated, with MCF-7 demonstrating an increased response to hydrostatic stimulus indicating MCF-7 being softer than 3T3, demonstrating the ability to provide qualitative data on cell mechanical behaviour. Quantitative measurements of 6% agarose beads have been taken with commercial Cell Scale Microsquisher® system demonstrating that their mechanical properties are in the same order of magnitude of cells, indicating that this is an appropriate test sample for the novel method desctibed

Biochemical fingerprint of colorectal cancer cell lines using label-free live single-cell Raman spectroscopy

Label-free live single-cell Raman spectroscopy was used to obtain a chemical fingerprint of colorectal cancer cells including the classification of the SW480 and SW620 cell line model system, derived from primary and secondary tumour cells from the same patient. High-quality Raman spectra were acquired from hundreds of live cells, showing high reproducibility between experiments. Principal component analysis with linear discriminant analysis yielded the best cell classification, with an accuracy of 98.7±0.3% (standard error) when compared to discrimination trees or support vector machines. SW480 showed higher content of the disordered secondary protein structure amide III band, whereas SW620 showed larger α-helix and β-sheet band content. The SW620 cell line also displayed higher nucleic acid, phosphates, saccharide, and CH2 content. HL60, HT29, HCT116, SW620 and SW480 live single-cell spectra were classified using PCA/LDA with an accuracy of 92.4±0.4% (standard error), showing differences mainly in the β-sheet content, the cytochrome C bands, the CH-stretching regions, the lactate contributions and the DNA content. The lipids contributions above 2900 cm-1 and the lactate contributions at 1785 cm-1 appeared to be dependent on the colorectal adenocarcinoma stage, the advanced stage cell lines showing lower lipid and higher lactate content. The results demonstrate that these cell lines can be distinguished with high confidence, suggesting that Raman spectroscopy on live cells can distinguish between different disease stages, and could play an important role clinically as a diagnostic tool for cell phenotyping

Label-free biomarkers of human embryonic stem cell differentiation to hepatocytes

Four different label-free, minimally invasive, live single cell analysis techniques were applied in a quantitative comparison, to characterize embryonic stem cells and the hepatocytes into which they were differentiated. Atomic force microscopy measures the cell's mechanical properties, Raman spectroscopy measures its chemical properties, and dielectrophoresis measures the membrane's capacitance. They were able to assign cell type of individual cells with accuracies of 91% (atomic force microscopy), 95.5% (Raman spectroscopy), and 72% (dielectrophoresis). In addition, stimulated Raman scattering (SRS) microscopy was able to easily identify hepatocytes in images by the presence of lipid droplets. These techniques, used either independently or in combination, offer label-free methods to study individual living cells. Although these minimally invasive biomarkers can be applied to sense phenotypical or environmental changes to cells, these techniques have most potential in human stem cell therapies where the use of traditional biomarkers is best avoided. Destructive assays consume valuable stem cells and do not characterize the cells which go on to be used in therapies; whereas immunolabeling risks altering cell behavior. It was suggested how these four minimally invasive methods could be applied to cell culture, and how they could in future be combined into one microfluidic chip for cell sorting

Vibrational spectroscopy and microscopy in colorectal cancer

This project set out to examine the possibility that by acquiring Raman spectra and performing multi-photon imaging we can get better diagnosis and understanding of the biochemistry of an individual cancerous tumour and distinguish it from the healthy tissue. Within the frame of this study, colorectal primary and secondary cancer cells are examined with Raman spectroscopy in order to (i) study and distinguish them according to their chemical composition by applying multivariate methods and (ii) determine whether Raman spectroscopy can identify the cells which are the link between primary and secondary colorectal cancer cells, the so-called Cancer Stem Cells. The second part of this thesis is based on tissue studies. Human colorectal tissue sections are examined in a label-free manner with the use of multi-photon imaging modes (i) Two photon excitation fluorescence, (ii) stimulated Raman scattering and (iii) second harmonic generation, in order to determine whether these can provide fast and accurate diagnosis of colorectal cancer. These techniques were able to distinguish between healthy and cancerous tissue regions, based on the chemically-specific images of the tissue microenvironment and architecture. The hypothesis of Cancer stem cell is examined with the use of Raman spectroscopy shown that the CSCs have some small differences according to their tissue origin