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Topic Review
Raman Spectroscopy
Cancer still constitutes one of the main global health challenges. Novel approaches towards understanding the molecular composition of the disease can be employed as adjuvant tools to current oncological applications. Raman spectroscopy has been contemplated and pursued to serve as a noninvasive, real time, in vivo tool which may uncover the molecular basis of cancer and simultaneously offer high specificity, sensitivity, and multiplexing capacity, as well as high spatial and temporal resolution.
  • 808
  • 11 Mar 2022
Topic Review
Raman Spectroelectrochemistry
Raman spectroelectrochemistry (Raman-SEC) is a technique that studies the inelastic scattering or Raman scattering of monochromatic light related to chemical compounds involved in an electrode process. This technique provides information about vibrational energy transitions of molecules, using a monochromatic light source, usually from a laser that belongs to the UV, Vis or NIR region. Raman spectroelectrochemistry provides specific information about structural changes, composition and orientation of the molecules on the electrode surface involved in an electrochemical reaction, being the Raman spectra registered a real fingerprint of the compounds. When a monochromatic light beam samples the electrode/solution interface, most of the photons are scattered elastically, with the same energy than the incident light. However, a small fraction is scattered inelastically, being the energy of the laser photons shifted up or down. When the scattering is elastic, the phenomenon is denoted as Rayleigh scattering, while when it is inelastic it is called Raman scattering. Raman spectroscopy combined with electrochemical techniques, makes Raman spectroelectrochemistry a powerful technique in the identification, characterization and quantification of molecules. The main advantage of Raman spectroelectrochemistry is that it is not limited to the selected solvent, and aqueous and organic solutions can be used. However, the main disadvantage is the intrinsic low Raman signal intensity. Different methods as well as new substrates were developed to improve the sensitivity and selectivity of this multirresponse technique.
  • 377
  • 14 Oct 2022
Topic Review
Raksha Bandhan
Raksha Bandhan, also Rakshabandhan, or Rakhi, is a popular, traditionally Hindu, annual rite, or ceremony, which is central to a festival of the same name, celebrated in parts of South Asia, and among people influenced by South Asian culture around the world. On this day, sisters of all ages tie a talisman, or amulet, called the rakhi, around the wrists of their brothers, symbolically protecting them, receiving a gift in return, and traditionally investing the brothers with a share of the responsibility of their potential care. Raksha Bandhan is observed on the last day of the Hindu lunar calendar month of Shraavana, which typically falls in August. The expression "Raksha Bandhan," Sanskrit, literally, "the bond of protection, obligation, or care," is now principally applied to this ritual. Until the mid-20th-century, the expression was more commonly applied to a similar ritual, also held on the same day, with precedence in ancient Hindu texts, in which a domestic priest ties amulets, charms, or threads on the wrists of his patrons, or changes their sacred thread, and receives gifts of money; in some places, this is still the case. In contrast, the sister-brother festival, with origins in folk culture, had names which varied with location, with some rendered as Saluno, Silono, and Rakri. A ritual associated with Saluno included the sisters placing shoots of barley behind the ears of their brothers. Of special significance to married women, Raksha Bandhan is rooted in the practice of territorial or village exogamy, in which a bride marries out of her natal village or town, and her parents, by custom, do not visit her in her married home. In rural north India, where village exogamy is strongly prevalent, large numbers of married Hindu women travel back to their parents' homes every year for the ceremony. Their brothers, who typically live with the parents or nearby, sometimes travel to their sisters' married home to escort them back. Many younger married women arrive a few weeks earlier at their natal homes and stay until the ceremony. The brothers serve as lifelong intermediaries between their sisters' married and parental homes, as well as potential stewards of their security. In urban India, where families are increasingly nuclear, the festival has become more symbolic, but continues to be highly popular. The rituals associated with this festival have spread beyond their traditional regions and have been transformed through technology and migration, the movies, social interaction, and promotion by politicized Hinduism, as well as by the nation state. Among women and men who are not blood relatives, there is also a transformed tradition of voluntary kin relations, achieved through the tying of rakhi amulets, which have cut across caste and class lines, and Hindu and Muslim divisions. In some communities or contexts, other figures, such as a matriarch, or a person in authority, can be included in the ceremony in ritual acknowledgement of their benefaction.
  • 1.4K
  • 18 Oct 2022
Topic Review
Rainbows in Culture
The rainbow, a natural phenomenon noted for its design and its place in the sky, has been a favorite component of art and religion throughout history.
  • 2.0K
  • 14 Oct 2022
Topic Review
Radiological Investigation of French Fossils
The accurate investigation of uranium-containing fossils in a museum of the City of Basel showed the following crucial points: 1 Storage of uranium-containing minerals or fossils may lead to elevated radon exposures for the staff. The monitoring of the room air is recommended: Eventual taken measures will reduce the exposure to radon (permanent air ventilation, airtight storage of contaminated objects). 2 The handling and preparation of such contaminated objects may lead to significant doses by inhalation of radioactive dust. Such work should not be envisaged without special precautions. These could be wearing protective mask and gloves, working in a clean-bench.
  • 794
  • 04 Jul 2021
Topic Review
Radiolabeled Gold Nanoseeds and Glioblastoma Multiforme
Glioblastoma multiforme (GBM), classified as a grade IV brain tumor, represents the most frequent brain tumor, accounting for approximately 12–15% of all intracranial neoplasms. Current therapeutic strategies for GBM rely on open surgery, chemotherapy and radiotherapy. Despite some progress in the past 30 years, the overall survival of patients with glioblastoma remains extremely poor. The average lifespan is approximately 15 months after diagnosis, with most patients experiencing tumor relapse and outgrowth within 7–10 months of initial radiation therapy.
  • 572
  • 14 Jan 2022
Topic Review
Radiography of Cultural Objects
The radiography of cultural objects is the use of radiography to understand intrinsic details about objects. Most commonly this involves X-rays of paintings to reveal underdrawing, pentimenti alterations in the course of painting or by later restorers, and sometimes previous paintings on the support. Many pigments such as lead white show well in radiographs. X-ray spectromicroscopy has also been used to analyse the reactions of pigments in paintings. For example, in analysing colour degradation in the paintings of van Gogh. These processes can reveal various details about objects that are not visible to the naked eye. This information, which includes structural elements, aids conservators as they assess object condition and consider treatment plans. For three dimensional objects, the computed tomography (CT) has become a common tool, which when combined with analysis can, for example, "digitally unroll" or unfold and make possible the reading of fragile scrolls, books, or sealed correspondence.
  • 451
  • 10 Oct 2022
Topic Review
Radiographic Imaging with Muons
Radiographic imaging with muons, also called Muography, is based on the measurement of the absorption of muons, generated by the interaction of cosmic rays with the earth’s atmosphere, in matter. Muons are elementary particles with high penetrating power, a characteristic that makes them capable of crossing bodies of dimensions of the order of hundreds of meters. 
  • 553
  • 08 Dec 2021
Topic Review
Radio-Mode Feedback in Galaxies
The Active Galactic Nuclei (AGN) population can be represented by two main categories. In the first category, Quasars and Seyfert galaxies, sources of high bolometric luminosities, capable of generating winds through radiation pressure due to its accretion rate close to Eddington, usually found in wide angle outflows, are commonly distinguished as radiative-mode (or sometimes also called as quasar-mode) AGN. In the second category, the so called radio-mode AGN (or jet-mode, or kinetic-mode), the central engine launches powerful collimated jets of relativistic particles accelerated in the inner regions of the accretion disk due to its intense magnetic fields. The origin of the difference between these two categories is believed to happen within the accretion disk structure and internal thermodynamics, and the resulting mass accretion rates.
  • 324
  • 28 Jun 2023
Topic Review
Radiative Transfer Equation and Diffusion Theory for Photon Transport in Biological Tissue
The RTE can mathematically model the transfer of energy as photons move inside a tissue. The flow of radiation energy through a small area element in the radiation field can be characterized by radiance [math]\displaystyle{ L(\vec{r},\hat{s},t) (\frac{W}{m^2 sr}) }[/math]. Radiance is defined as energy flow per unit normal area per unit solid angle per unit time. Here, [math]\displaystyle{ \vec{r} }[/math] denotes position, [math]\displaystyle{ \hat{s} }[/math] denotes unit direction vector and [math]\displaystyle{ t }[/math] denotes time. 
  • 1.3K
  • 16 Nov 2022
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