We report the effect of an atherogenic diet supplemented with cis-9, trans-11-octadecadienoic acid (c9t11), linoleic acid (LA) or an isomeric mixture of conjugated linoleic acids (CLA) on plasma lipids, weight gain and food intake of male Golden Syrian hamsters. Animals were assigned to three diet groups (n = 10), and fed nonpurified diet, supplemented with 10% hydrogenated coconut oil and 0.05% cholesterol for 6 wk. The first diet group was further supplemented with 1% CLA (CLA group), the second diet group with 0.2% c9t11 (c9t11 group) and the third group with 0.2% LA (LA group). The diets were designed to have equivalent levels of c9t11 in the CLA and c9t11 groups. At 2 and 6 wk of feeding, the CLA group had significantly lower plasma triglyceride and total cholesterol concentrations than either the c9t11 or the LA groups. HDL-cholesterol did not differ among diet groups. The CLA group had significantly lower weight gain but greater food intake than either the c9t11 or the LA groups. There were no significant differences between the c9t11 and the LA groups in any of the variables measured. We conclude that under our experimental conditions of short-term feeding, c9t11, thought to be the active compound in CLA, does not produce the same effect as the isomer mixture.

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The use of a visual 3D display and a virtual spectrometer for the teaching of a course in molecular spectroscopy presents new possibilities. All the movements of the molecules are shown along with their relations with their characteristic spectra. The virtual laboratory simulates a true commercial spectrometer as well as a software of recognition. All the students simultaneously follow the laboratory under conditions very close to the reality of a modern industrial laboratory. SummaryTeaching a course in molecular spectroscopy is not an easy task. First, we must use concepts of molecular symmetry to relate the observed spectra to the quantum properties of the molecules, such as the creation or the modification of an electric dipole moment or the quantified energy levels. The visualization of these 3D symmetry properties is not easy, and the use of sticks and ball models has become complicated and obsolete today. Second FTIR spectroscopy now involves very expensive equipment and signal analysers. Teaching laboratories often lack the number of spectrometers required for teaching large groups of students, and, even less, the expensive software to analyze and recognize the spectra. The result is that the students are not trained with modern apparatus and under the conditions normally met in their future work place. Sometimes they are also obliged to apply concepts in the laboratory, which they will learn only later in class. The development of the information and communications technology (ICT) enables us to conceive the teaching of such courses differently. The first problem is easily solved by developing a 3D visual display with the six degrees of freedom which describe the translation and the rotation of the whole molecule. Moreover, the 3N minus six (or five for linear molecule) degrees of freedom of a N atoms molecule can also be illustrated, showing all the movement of the atoms. So we can simulate the normal modes of vibration of a molecule or of a group and correlate them with their spectra. We have done this with the Java 3D language, and using the spectra from the National Institute of Standards and Technology (NIST) site. Several molecules were simulated, so that all the symmetry operations are presented, as well as some normal modes of vibration of This paper is freely available as a resource for the optics and photonics education community.