Food Intake and Colorectal Cancer.

Colorectal cancer (CRC) accounts for considerable mortalities worldwide. Several modifiable risk factors, including a high intake of certain foods and beverages can cause CRC. This review summarized the latest findings on the intake of various foods, nutrients, ingredients, and beverages on CRC development, with the objective of classifying them as a risk or protective factor. High-risk food items include red meat, processed meat, eggs, high alcohol consumption, sugar-sweetened beverages, and chocolate candy. Food items that are protective include milk, cheese and other dairy products, fruits, vegetables (particularly cruciferous), whole grains, legumes (particularly soy beans), fish, tea (particularly green tea), coffee (particularly among Asians), chocolate, and moderate alcohol consumption (particularly wine). High-risk nutrients/ingredients include dietary fat from animal sources and industrial trans-fatty acids (semisolid/solid hydrogenated oils), synthetic food coloring, monosodium glutamate, titanium dioxide, and high-fructose corn sirup. Nutrients/ingredients that are protective include dietary fiber (particularly from cereals), fatty acids (medium-chain and odd-chain saturated fatty acids and highly unsaturated fatty acids, including omega-3 polyunsaturated fatty acids), calcium, polyphenols, curcumin, selenium, zinc, magnesium, and vitamins A, C, D, E, and B (particularly B6, B9, and B2). A combination of micronutrients and multi-vitamins also appears to be beneficial in reducing recurrent adenoma incidence.

Detection sensitivity of laser-induced breakdown spectroscopy for Cr II in liquid samples.

The performance of laser-induced breakdown spectroscopy (LIBS) has been evaluated for detection of toxic metals such as Cr in water. Pure aqueous solutions (unitary matrix) with variable Cr concentration were used to construct calibration curves and to estimate the LIBS limit of detection (LOD). The calibration curves for Cr in a binary matrix (Cr plus Cd) and a tertiary matrix (Cr plus Cd and Co) were used to evaluate the matrix effect on the LOD. The LOD for Cr was found to be 1.1, 1.5, and 2.0 ppm (parts in 10(6)) in a unitary, binary, and tertiary matrix, respectively. Once calibrated, the system was utilized for the detection and quantification of the Cr in tannery wastewater collected from different locations in the industrial area of Kanpur, India, where Cr concentrations were determined to be far higher than the U.S. Environmental Protection Agency safe drinking water limit of 0.05 ppm.

Characterization of malignant tissue cells by laser-induced breakdown spectroscopy.

Cancer diagnosis and classification is extremely complicated and, for the most part, relies on subjective interpretation of biopsy material. Such methods are laborious and in some cases might result in different results depending on the histopathologist doing the examination. Automated, real-time diagnostic procedures would greatly facilitate cancer diagnosis and classification. Laser-induced breakdown spectroscopy (LIBS) is used for the first time to our knowledge to distinguish normal and malignant tumor cells from histological sections. We found that the concentration of trace elements in normal and tumor cells was significantly different. For comparison, the tissue samples were also analyzed by an inductively coupled plasma emission spectroscopy (ICPES) system. The results from the LIBS measurement and ICPES analysis were in good agreement.

Double-pulse laser-induced breakdown spectroscopy with liquid jets of different thicknesses.

Double-pulse laser-induced breakdown spectroscopy of magnesium in water has been performed with different jet thicknesses. A Meinhard nebulizer has been used to create a jet of 0.3-mm diameter, whereas a homemade liquid jet injector produced a thicker jet of 1.0-mm diameter. The relationship of line intensity to delay time between the two laser pulses for these two jets is compared and discussed. The limits of detection in these two jets are also determined and compared. The line intensity observed from the double-pulse measurement is correlated with the measured electron density calculated with the Halpha line. Also, the behavior of plasma density relative to time delay between the lasers is described.

Detection of trace elements in liquids by laser-induced breakdown spectroscopy with a Meinhard nebulizer.

The laser-induced breakdown spectroscopy of magnesium, manganese, and chromium atoms by use of a commercial Meinhard nebulizer originally designed for inductively coupled plasma measurements is described. This is the first time, to our knowledge, that this nebulizer has been used for laser-induced breakdown spectroscopy measurements. The limit of detection is slightly lower when the nebulizer rather than a liquid jet is used in single-pulse laser excitation. In addition we present the response characteristics of the nebulizer, such as effects of variations in purge gas and liquid flow rate, that are different from normal operating specifications. The effects of gate delay, gate width, and laser power variations were also studied. The objective of the present research has been to consider a new operating mode and conditions in which a better limit of detection of trace elements in water can be obtained.

Effect of steady magnetic field on laser-induced breakdown spectroscopy.

Effects of a steady magnetic field on the laser-induced breakdown spectroscopy of certain elements (Mn, Mg, Cr, and Ti) in aqueous solution were studied, in which the plasma plume expanded across an external steady magnetic field (approximately 6 kilogauss). Nearly 1.6 times enhancement in the line emission intensity was observed in the presence of the magnetic field. The temporal evolution of the line emission showed a significant enhancement in plasma emission between 2- and 7- micro(s) gate delays for Mg in the presence of the magnetic field (5-30 micro(s) for Mn). This enhancement in the emission is attributed to an increase in the rate of recombination because of an increase in plasma density due to a magnetic confinement after cooling the plasma. The increase in the optical line emission due to magnetic confinement was absent when the plasma was hot with a dominant background (continuum) emission. The limits of detection of Mg and Mn were reduced by a factor of two in the presence of a steady magnetic field of 5 kilogauss.

Optical properties of Sm3+ ions doped in tellurite glass.

Judd-Ofelt analysis of Sm(3+) ions doped in a tellurite glass has been accomplished. Fluorescence and life-time measurements have been carried out using Ar(+) laser and excimer laser. Stark splitting has been observed in the upper and lower levels in fluorescence. The life-time of 4G(5/2) level as a function of Sm(3+) concentration has been measured. Concentration quenching and the mechanism responsible for the same have been found.

Optical studies of Eu3+ ions doped in tellurite glass.

Absorption and fluorescence spectra of Eu3+ ions doped in a tellurite glass have been recorded and analysed. Judd-Ofelt analysis has been done in order to calculate the different optical parameters such as oscillator strength, Judd-Ofelt intensity parameters, stimulated emission cross-section, transition probability, branching ratio, radiative lifetime, etc. Lifetime measurements of the 5D0 level as a function of Eu3+ concentration have been used to explore the concentration quenching process. The mechanism of quenching is found to be of a dipole-dipole type.

Optical properties of Nd3+ ions doped in oxyfluoroborate glass.

Laser induced excitation spectrum of the Nd3+ ions doped in oxyfluoroborate glass have been recorded. Stark components of different electronic states have been reported. Judd-Ofelt analysis has also been accomplished on the basis of ultraviolet-visible-near-infrared (UV-vis-NIR) absorption spectrum. Various radiative parameters such as electric dipole line strength, transition probability, life time of the various energy levels, branching ratio etc., have been estimated.

Optical properties of Er3+ ions doped in oxyfluoroborate glass.

In this paper the Stark components of 4S(3/2), 2H(11/2) and 4I(15/2) levels of Er3+ ion doped in oxyfluoroborate glass have been resolved using laser excitation and fluorescence measurements. The lifetime of 4S(3/2) level as a function of Er3+ concentration in the glass host has also been measured. Concentration quenching due to interaction among rare earth ions and the mechanism responsible for the same has been elucidated. The Judd-Ofelt analysis of the absorption spectrum has also been carried out.