Beam quality improvement of laser diode array by using off-axis external cavity

A novel off-axis external cavity is designed for laser diode array to improve the beam quality. In this external cavity, a circle aperture with variable size is used as a spatial filter. The diameter of aperture is optimized to 1.2mm and the off-axis angle of external cavity is optimized at 2.6 deg. In the optimal case, the beam parameter product (BPP) of laser diode array is reduced to 121 mm. mrad from 1050 mm. mrad with external cavity optical efficiency of 81%. (C) 2007 Optical Society of America.

Nutritional quality of some food fish

The proximate compositions and amino acid make-up of silver jew fish (Johnius argentatus), Indian halibut (Psettodes erumei), grey mullet (Mugil cephalus) and pearl spot (Etroplus suratensis) are reported. Calorific values of these fishes have been calculated from their proximate compositions and their amino acid make-up compared with the available data for beef and egg. From the study, pearl spot is adjudged to be the most nutritive among the fishes studied, followed by Indian halibut, grey mullet and silver jew fish.

Red and white meat of tuna (Euthynnus affinis): their biochemical role and nutritional quality

The biochemical and nutrient compositions of red and white meat of tuna are reported. Based on the data the biochemical role and nutritional quality of red and white meat are discussed. The results show that red meat is adapted for slow and continuous activity and white meat for quick but occasional activity. In spite of comparatively low lysine content the red meat is adjudged more nutritious than white meat.

Oxidation of residual lipids in fish protein concentrates and its effect on the nutritional quality of the protein

The paper reviews the work reported on the changes in the nutritive value of fish protein concentrates (FPC) during, storage, with special emphasis on the effects of the interactions between oxidised residual lipids and proteins of the FPC. Theories on the oxidised lipid-protein interactions are reviewed and the nutritional significance of these reactions is discussed.

Nutritional evaluation of some freshwater fishes

The proximate composition, amino acid composition and the PER values of Rohu (Labeo rohita), Mrigal (Cirrhina mrigala) and Calbasu (Labeo calbasu) are reported. The proximate composition of all the three fishes was similar. However the amino acid composition varied considerably. Protein quality index of the three fish proteins calculated from the amino acid composition are also reported. The nutritional quality of the 3 types of proteins to meet the growth requirements of infants, children and adult human beings is discussed. The possibility of substantial improvement in nutritional quality of the three fish proteins to suit the requirements of infants and children by marginal supplementation with valine/valine-rich food for rohu and valine and isoleucine/food rich in valine and isoleucine for mrigal and calbasu is also discussed. The results indicate that of the three fishes rohu is the best in protein quality followed by mrigal and calbasu. All of them have a better amino acid make up than casein to meet the amino acid requirement of adults.

Studies on the chemical and nutritional quality of protein powders isolated from shrimp waste

Protein powders were prepared from processing waste of prawns either by mechanically squeezing the shell and freeze drying the resultant aqueous extract or by treating the shell with 0.5% sodium hydroxide, filtering it and freeze drying the filtrate. Comparative studies on the proximate composition, amino acid profile, consumer acceptability and nutritional quality of the protein powders showed that the product prepared by freeze drying of the press liquor obtained by passing the waste through a hand operated expeller is better in all aspects studied than the product prepared by mild alkali extraction.

Quality improvement of GaInNAs/GaAs quantum wells grown by plasma-assisted molecular beam epitaxy

The optimum growth condition of GaInNAs/GaAs quantum wells (QWs) by plasma-assisted molecular beam epitaxy was investigated. High-resolution X-ray diffraction and photoluminescence (PL) measurements showed that ion damage drastically degraded the quality of GaNAs and GaInNAs QWs and that ion removal magnets can effectively remove the excess ion damage. Remarkable improvement of PL intensity and obvious appearance of pendellosung fringes were observed by removing the N ions produced in the plasma cell. When the growth rate increased from 0.73 to 1.2 ML/s, the optimum growth temperature was raised from 460 degreesC to 480 degreesC and PL peak intensity increased two times. Although the N composition decreased with increasing growth rate, degradation of optical properties of GaInNAs QWs was observed when the growth rate was over 0.92 ML/s. Due to low-temperature growth of GaInNAs QWs, a distinctive reflection high-energy electron diffraction pattern was observed only when the GaAs barrier was grown under lower As-4 pressure. The samples with GaAs barriers grown under lower As-4 pressure (V/III ratio about 24) exhibited seven times increase in PL peak intensity compared with those grown under higher As-4 pressure (V/III ratio about 50). (C) 2001 Elsevier Science B,V. All rights reserved.

Quality improvement of GaInNAs/GaAs quantum wells grown by plasma-assisted molecular beam epitaxy

The optimum growth condition of GaInNAs/GaAs quantum wells (QWs) by plasma-assisted molecular beam epitaxy was investigated. High-resolution X-ray diffraction and photoluminescence (PL) measurements showed that ion damage drastically degraded the quality of GaNAs and GaInNAs QWs and that ion removal magnets can effectively remove the excess ion damage. Remarkable improvement of PL intensity and obvious appearance of pendellosung fringes were observed by removing the N ions produced in the plasma cell. When the growth rate increased from 0.73 to 1.2 ML/s, the optimum growth temperature was raised from 460 degreesC to 480 degreesC and PL peak intensity increased two times. Although the N composition decreased with increasing growth rate, degradation of optical properties of GaInNAs QWs was observed when the growth rate was over 0.92 ML/s. Due to low-temperature growth of GaInNAs QWs, a distinctive reflection high-energy electron diffraction pattern was observed only when the GaAs barrier was grown under lower As-4 pressure. The samples with GaAs barriers grown under lower As-4 pressure (V/III ratio about 24) exhibited seven times increase in PL peak intensity compared with those grown under higher As-4 pressure (V/III ratio about 50). (C) 2001 Elsevier Science B,V. All rights reserved.

Marine yeast Candida MCCF 101 as feed supplement in aquaculture: nutritional quality, optimization of large scale production and evaluation of its protective effect on Koi carp from Aeromonas infection

Marine yeast have been regarded as safe and showing a beneficial impact on biotechnological process. It provides better nutritional and dietary values indicating their potential application as feed supplements in aquaculture. Brown et al. (1996) evaluated all the marine yeasts characterised with high protein content, carbohydrate, good amino acid composition and high levels of saturated fats. However, there is paucity of information on marine yeasts as feed supplements and no feed formulation has been found either in literature or in market supplemented with them. This statement supported by Zhenming et al. (2006) reported still a lack of feed composed of single cell protein (SCP) from marine yeasts with high content of protein and other nutrients. Recent research has shown that marine yeasts also have highly potential uses in food, feed, medical and biofuel industries as well as marine biotechnology (Chi et al., 2009; 2010). Sajeevan et al. (2006; 2009a) and Sarlin and Philip (2011) demonstrates that the marine yeasts Candida sake served as a high quality, inexpensive nutrient source and it had proven immunostimulatory properties for cultured shrimps. This strain has been made part of the culture collection of National Centre for Aquatic Animal Health, Cochin University of Science and Technology as Candida MCCF 101. Over the years marine yeasts have been gaining increased attention in animal feed industry due to their nutritional value and immune boosting property.Therefore, the present study was undertaken, and focused on the nutritional quality, optimization of large scale production and evaluation of its protective effect on Koi carp from Aeromonas infection

Improving the nutritional quality of milk

Epidemiological evidence suggests high milk consumption protects against certain chronic diseases, and yet the high saturated fatty acid (SFA) concentration of milk fat has lead to research into reducing SFA and trans- fatty acid content, and enhancing conjugated linoleic acid (CLA) content. The most successful method of reducing SFA content is by feeding dairy cows supplemental oilseeds, although amount, type and form of oilseed influence the degree of effect. Also, the high unsaturated fatty acid content of oilseeds leads to increases in milk fat trans- fatty acids unless the oilseed is protected from rumen metabolism.