Search results for "Color"
showing 10 items of 2721 documents
Multicolor 3D Printing of Complex Intracranial Tumors in Neurosurgery.
2020
Three-dimensional (3D) printing technologies offer the possibility of visualizing patient-specific pathologies in a physical model of correct dimensions. The model can be used for planning and simulating critical steps of a surgical approach. Therefore, it is important that anatomical structures such as blood vessels inside a tumor can be printed to be colored not only on their surface, but throughout their whole volume. During simulation this allows for the removal of certain parts (e.g., with a high-speed drill) and revealing internally located structures of a different color. Thus, diagnostic information from various imaging modalities (e.g., CT, MRI) can be combined in a single compact …
Triggering dissymmetry in achiral dye molecules by chiral solvents: Circular dichroism experiments and DFT calculations
2011
The electronic circular dichroism spectra of achiral product “Lumogen F Red” (ROT-300) in four different chiral solvents are recorded at different temperatures. DFT calculations allow to identify two enantiomeric conformers for ROT-300. In vacuo they are equally populated; in chiral solvents one enantiomer prevails. Thermodynamic quantities involved in the chiral preference are derived. Chirality, 2011. © 2011 Wiley-Liss, Inc.
Impact of local compressive stress on the optical transitions of single organic dye molecules
2012
The ability to mechanically control the optical properties of individual molecules is a grand challenge in nanoscience and could enable the manipulation of chemical reactivity at the single-molecule level. In the past, light has been used to alter the emission wavelength of individual molecules or modulate the energy transfer quantum yield between them. Furthermore, tensile stress has been applied to study the force dependence of protein folding/unfolding and of the chemistry and photochemistry of single molecules, although in these mechanical experiments the strength of the weakest bond limits the amount of applicable force. Here, we show that compressive stress modifies the photophysical …
Double-Network-Structured Graphene Oxide-Containing Nanogels as Photothermal Agents for the Treatment of Colorectal Cancer.
2017
Here, we reported the production of hyaluronic acid/polyaspartamide-based double-network nanogels for the potential treatment of colorectal carcinoma. Graphene oxide, thanks to the huge aromatic surface area, allows to easily load high amount of irinotecan (33.0% w/w) and confers to the system hyperthermic properties when irradiated with a near-infrared (NIR) laser beam. We demonstrate that the release of antitumor drug is influenced both by the pH of the external medium and the NIR irradiation process. In vitro biological studies, conducted on human colon cancer cells (HCT 116), revealed that nanogels are uptaken by the cancer cells and, in the presence of the antitumor drug, can produce a…
Single-Molecule FRET Reveals a Cooperative Effect of Two Methyl Group Modifications in the Folding of Human Mitochondrial tRNALys
2011
Summary Using a combination of advanced RNA synthesis techniques and single molecule spectroscopy, the deconvolution of individual contributions of posttranscriptional modifications to the overall folding and stabilization of human mitochondrial tRNA Lys is described. An unexpected destabilizing effect of two pseudouridines on the native tRNA folding was evidenced. Furthermore, the presence of m 2 G10 alone does not facilitate the folding of tRNA Lys , but a stabilization of the biologically functional cloverleaf shape in conjunction with the principal stabilizing component m 1 A9 exceeds the contribution of m 1 A alone. This constitutes an unprecedented cooperative effect of two nucleotide…
Decarboxylation and alkaline colour fading reactions in presence of humic substances.
2002
Humic substances (HSs) can substantially influence velocity of reactions in the environment as shown on example of decarboxylation and alkaline colour (e.g., malachite green and crystal violet) fading reactions. In colour fading and decarboxylation reactions of 6-nitrobenzisoxazole-3-carboxylic acid HS act as inhibitors, but additions of surfactants change the pattern of reaction. The inhibitory activity of HSs much depends on their origin. The velocity of studied reactions depends also on pH, temperature and concentration of HS used. Possible micellar catalysis mechanism has been suggested.
Electrostatic control of the photoisomerization efficiency and optical properties in visual pigments: on the role of counterion quenching.
2009
Hybrid QM(CASPT2//CASSCF/6-31G*)/MM(Amber) computations have been used to map the photoisomerization path of the retinal chromophore in Rhodopsin and explore the reasons behind the photoactivity efficiency and spectral control in the visual pigments. It is shown that while the electrostatic environment plays a central role in properly tuning the optical properties of the chromophore, it is also critical in biasing the ultrafast photochemical event: it controls the slope of the photoisomerization channel as well as the accessibility of the S(1)/S(0) crossing space triggering the ultrafast decay. The roles of the E113 counterion, the E181 residue, and the other amino acids of the protein pock…
Nano-materials for use in sensing of salmonella infections: Recent advances
2016
Salmonella infectious diseases spreading every day through food have become a life-threatening problem for millions of people and growing menace to society. Health expert's estimate that the yearly cost of all the food borne diseases is approximately $5-6 billion. Traditional methodologies for salmonella analysis provide high reliability and very low limits of detection. Among them immunoassays and Nucleic acid-based assays provide results within 24h, but they are expensive, tedious and time consuming. So, there is an urgent need for development of rapid, robust and cost-effective alternative technologies for real-time monitoring of salmonella. Several biosensors have been designed and comm…
Molecular volumes and surfaces of biomacromolecules via GEPOL: A fast and efficient algorithm
1990
A triangular tesselation approach to build up surfaces has been adapted to the study of biomolecules. By using a data-coded generic pentakisdodecahedron each atom is assigned a particular sphere whose radii are chosen according to any suitable property. Different types of surfaces have been adapted to this method: van der Waals, surface accessible, and Richard's molecular surface. A simple method is used to eliminate all triangles found at the intersection volume of the atomic spheres and a fast algorithm is employed to calculate the area of the envelope surface and the volume therein. The data about the surface are given by the coordinates of the center of each triangle, elementary surface…
Characterization of aCandida albicansgene encoding a putative transcriptional factor required for cell wall integrity
2003
After screening a Candida albicans genome database the product of an open reading frame (ORF) (CA2880) with 49% homology to the product of Saccharomyces cerevisiae YPL133c, a putative transcriptional factor, was identified. The disruption of the C. albicans gene leads to a major sensitivity to calcofluor white and Congo red, a minor sensitivity to sodium dodecyl sulfate, a major resistance to zymolyase, and an alteration of the chemical composition of the cell wall. For these reasons we called it CaCWT1 (for C. albicans cell wall transcription factor). CaCwt1p contains a putative Zn(II) Cys(6) DNA binding domain characteristic of some transcriptional factors and a PAS domain. The CaCWT1 gen…