Distributed sensor for water and pH measurements using fiber optics and swellable polymeric systems.

We report on the design, construction and test of a generic form of sensor for making distributed measurements of a range of chemical parameters. The technique combines optical time-domain reflectometry with chemically sensitive water-swellable polymers (hydrogels). Initial experiments have concentrated on demonstrating a distributed water detector; however, gels have been developed that enable this sensor to be readily adapted to distributed pH measurements.

Simultaneous recovery of strain and temperature fields by the use of two-moded polarimetry with an in-line mode splitter/analyzer.

We report the simultaneous recovery of temperature and strain through measurement of polarization changes in the LP(01) and LP(11) modes of Andrew Corporation elliptical-core fiber. This technique required the development of an in-line mode splittery/analyzer, which is also described. The scheme has been demonstrated to be sensitive to changes of 1 degrees C and 5 microepsilon and is compatible with white-light multiplexing methods to provide quasidistributed information.

Effect of different dietary supplemental fats and oils on the tissue fatty acid composition and growth of female broilers.

1. A study was undertaken to examine the effect of supplementation of diets with fats of different chain length and degree of unsaturation on the performance, carcase characteristics and tissue fatty acid composition of broilers. 2. Three hundred and sixty 19-day-old female broilers were fed on diets containing supplemental fat/oil (50 g/kg) in the form of beef tallow (BT) (diet T-T), soyabean oil (SBO) (diet S-S), rapeseed oil (RSO) (diet R-R), marine oil (MO) (diet M-M) or binary mixtures (0.5:0.5 w/w) of these lipids (diets T-S, T-R, T-M, S-R, S-M, and R-M) to 54 d of age. Food intake, live weight, plucked weight and the lipid concentration and fatty acid composition of abdominal fat pad, liver and breast muscle were measured. 3. Food intake, plucked weight and live weight were greatest for diet T-T and lowest for diet R-R. Food conversion ratio was poorest for birds fed on diets containing BT. Lipid concentration in abdominal fat pad was significantly higher in birds fed on diets containing SBO. Liver lipid concentration was significantly reduced by diets containing RSO. 4. Abdominal fat pad fatty acid profile was most readily altered by dietary fatty acids. There was a strong correlation between dietary fatty acid composition and tissue fatty acid composition for all fatty acids except C14:0, C20:0, C20: 2n-6 and C20: 4n-6. The tissue P/S ratio ranged from 0.40 for diet T-T to 1.40 for diet S-S. The n-6/n-3 ratio was significantly increased by the inclusion of SBO and decreased by the inclusion of MO. 5. Liver fatty acid profile was least modified by dietary fatty acids. There was an inverse relationship between liver and dietary C20:4n-6 concentration. Tissue C18:2n-6 and C20:4n-6 were highly correlated, suggesting significant interconversion by delta-6 desaturase in this tissue. The n-6/n-3 ratio was significantly increased by inclusion of SBO and significantly decreased by the inclusion of MO. 6. In breast muscle MO-based diets increased the proportion of n-3 PUFA at the expense of n-6 PUFA. The tissue concentrations of C18:1n-9, C18:2n-6, C20:1n-9, C20:5n-3, C22:5n-3 and C22:6n-3 were strongly correlated with dietary fatty acid composition. Muscle and diet P/S and n-6/n-3 ratios were highly correlated.

Environmental temperature and dietary protein concentrations for growing turkeys.

Growing turkeys were kept at one of 4 constant temperatures (14, 17, 20 or 23 degrees C) from 10 to 15 weeks of age and given a food with one of three protein concentrations (201, 229 or 294 g/kg diet). Food intakes, food conversion ratios and breast meat yields (as a proportion of body weight) were decreased at the higher temperatures but there were no significant differences in growth. At each temperature, the turkeys given the higher dietary protein concentrations had increased body weight gains but their breast meat yields were similar. Thus the poor breast meat yields which resulted from rearing at high temperatures could not be counteracted by high dietary protein concentrations.

Comparison of artificial light sources and lighting programmes for laying hens on long ahemeral light cycles.

Three lighting treatments were given to laying hens, for which the bright and dim light of 28-h ahemeral light cycles was provided by incandescent (tungsten filament) lamps only or by combinations of tubular fluorescent or compact gas-discharge lamps with incandescent lamps. There were no differences in entrainment (the proportion of eggs laid in 4, 6 or 8 h modal periods) between the three bright:dim treatments. A fourth ahemeral lighting treatment in which the dim lights were extinguished except during a designated work period (09.00 h to 12.00 h daily) was termed bright:dim:dark. Hens given the bright:dim:dark treatment showed an increased entrainment compared with the three bright:dim light treatments. There were no differences (P greater than 0.05) in egg numbers or mean egg weight between all 4 lighting treatments. Birds given the bright:dim:dark treatment tended to have a lower (P greater than 0.05) food intake compared to the three bright:dim treatments.

Raised environmental temperature and food rationing as means of restricting growth of the replacement pullet.

1. Four rearing temperature regimes (15, 20, 25, 30 degrees C) and three feeding schedules (ad libitum, restricting to the ad libitum intake of the 12th week and feeding 70% of this rate) were carried out with layer replacement pullets to 170 d of age. From this age, during lay, birds were kept at either 21 degrees C or on a 24-h cycle of 21 for 18 h and 28 degrees C for the 6 h before lights out. Both a white and a brown egg-laying strain were used. 2. Body weight at 169 d of age varied from, on average, 1409 g (15 degrees C, ad libitum) to 943 g (30 degrees C, 70% schedule) for the white strain and 1947 to 1250 g for the same treatments respectively for the brown strain. Sexual maturity was considerably delayed by the 70% feeding schedule, only slightly by rearing at 30 degrees C. 3. Rearing at 30 degrees C tended to depress subsequent egg output. The 70% feeding schedule at least maintained egg output compared with birds fed ad libitum in rearing. 4. There was a highly significant effect of temperature treatment during lay on food intake. The reduction in food intake due to the 21-28 degrees C cycle, however, appeared small.

The food intakes and growth of choice-fed turkeys offered balancer mixtures of different compositions.

1. Choice-fed growing turkeys were offered whole wheat and each of six balancer mixtures. The compositions of the balancers were identical except for the content of ground cereals. 2. In a second experiment, choice-fed growing turkeys were offered whole wheat and each of four balancers which varied only in their calculated metabolisable energy (ME) content and the type of protein concentrate. 3. The turkeys which were fed on balancers of high white fish meal content ate more whole wheat and correspondingly less balancer than the turkeys offered balancers of high meat and bone meal content. 4. The ME content of the balancer did not affect the food intakes of the turkeys in the total feeding period. A high proportion of barley in the balancer hastened the increase in whole wheat intake after the introduction of the choice-feeding regime.

Environmental temperature and choice feeding of the broiler.

1. Broilers were kept under environmental temperature regimens of 16, 21, 26 or 31 degrees and given, 22--57 d of age, either a complete diet or free-choice of whole wheat and a higher-protein food containing either 252 or 516 g crude protein (nitrogen x 6.25)/kg. 2. Broilers maintained at 16 and 21 degrees consumed food at a significantly higher rate than those kept at 26 degrees and the latter had a significantly higher food intake rate than broilers kept at 31 degrees, for each feeding treatment. Compared with 21 degrees the 57 d body-weight of broilers kept at 26 degrees and 31 degrees was significantly reduced. 3. When kept under the 16, 21, 26 and 31 degrees regimens, the amount of whole wheat in the food consumed by the broilers choice-fed with wheat and the 252 g crude protein/kg food was 56, 55, 48 and 46% respectively. The corresponding values for the broilers on the second choice-feeding treatment were 80, 76, 79 and 72%. 4. Except for a single instance the choice-fed broilers grew at a significantly slower rate than broilers given the complete diet.

Outcome of sub-total thyroidectomy for thyrotoxicosis in Iceland and Northeast Scotland.

A comparative study of the outcome of surgical treatment for thyrotoxicosis was carried out in two countries with dissimilar dietary iodine levels. In the area with a high iodine level (Iceland) the prevalence of post-operative hypothyroidism was five times lower, but recurrent hyperthyroidism was five times higher, than in the area with lower iodine levels (northeast Scotland). The total morbidity reached comparable levels in the two samples. The prevalence of positive thyroid antibody tests and serum thyrotrophin levels was lower and the functional capacity of the thyroid remnant higher in the area with the higher dietary iodine intake. The study provides further evidence that there are important regional differences in the prevalence of factors known to influence the response to surgical treatment of thyrotoxicosis which should be taken into account when planning treatment services.

Does preoperative iodide treatment for thyrotoxicosis bring about involution?

It is generally believed that preoperative iodide decreases the hyperplasia of the toxic thyroid gland. Histometric studies of glands from thyrotoxic patients pretreated with propranolol alone compared with those from patients pretreated with propranolol and iodide failed to confirm this. Although histological appearances and volume percentage measurement of component tissues suggested that the glandular epithelium had involuted after iodine treatment, measurement of their absolute mass indicated that the mean mass of epithelium was the same in both groups and that involution had not occurred. We conclude that considerable confusion in the thyroid literature has arisen through incorrect use of the term involution.

Thyroid cancer in an iodide rich area: a histopathological study.

A comparison of the incidence of the different histological types of thyroid carcinoma in an area of high dietary iodide and an area of normal iodide intake has been made. The areas chosen were Iceland and the region of Northeast Scotland centred on Aberdeen; both areas have clearly defined populations served by a single pathology laboratory. All definite and dubious thyroid carcinomas from both regions were examined and classified by the same two pathologists. The age-specific incidence rates for papillary carcinoma in surgical specimens in both areas rose with age; they were five times higher in Iceland (high iodide area) than in Northeast Scotland. The numbers of follicular carcinomas were small, and this tumor was relatively less frequent in Iceland than Aberdeen. These findings, together with the known high relative frequency of follicular carcinoma and low frequency of papillary carcinoma in areas of endemic goitre, lead to the suggestion that the incidence of papillary carcinoma and follicular carcinoma are separately influenced by dietary iodide, papillary carcinoma being high in areas of high iodide intake and low in areas with low dietary iodide. No evidence to implicate lymphocytic thyroiditis, radiation or genetic factors in the genesis of thyroid carcinoma in Iceland or Northeast Scotland was found in this study. Undifferentiated carcinoma was about three times as common in Iceland as in Northeast Scotland. Malignant lymphoma of the thyroid was suprisingly common in Northeast Scotland, possibly related to the high frequency of thyroiditis found in this region. These studies suggest that the incidence of different histological types of thyroid malignancy is influenced by different etiological factors. They also provide support for the subdivision of thyroid malignancy into these different types, and for the general importance of accurate histological typing in cancer epidemiology.

Histometry of lymphoid infiltrate in the thyroid of primary thyrotoxicosis patients. Relation of extent of thyroiditis to preoperative drug treatment and postoperative hypothyroidism.

The thyroids of primary thyrotoxicosis patients prepared for partial thyroidectomy with propranolol contained much more lymphoid infiltrate than those prepared with carbimazole. No relation was found between the extent of lymphoid infiltrate in the thyroid and the development of postoperative hypothyroidism either between or within the two drug treatment groups. This study has shown that the extent of thyroid infiltrate should not be used as the major factor in predicting hypothyroidism after subtotal thyroidectomy for primary thyrotoxicosis.

The influence of preoperative drug treatment on the extent of hyperplasia of the thymus in primary thyrotoxicosis.

Thymic biopsies taken from women at the beginning of the operation of subtotal thyroidectomy were studied by the point-counting histometric technique. In all patients with primary thyrotoxicosis, the thymus is hyperplastic. After pretreatment with antithyroid drugs, the pattern of thymic involution with age is similar to, but at higher levels, than that in control groups of patients with non-toxic goitre in whom there is no evidence of immunological abnormality. By contrast, after propranolol pretreatment very little age involution is seen. The differences in the appearance of the thymus in female primary thyrotoxixosis patients prepared for operation with different drug treatment regimes are probably related to the pharmacological actions of the drugs and may indicate an interaction between primary immunological and secondary endocrinological factors in the disease process.

Whither thyrotoxicosis?

For 30 years the thyrotoxic patient has been subjected to a plurality of treatments by surgery, radio-iodine and long term anti-thyroid drugs. These therapies have been accepted as complementary to the needs of the individual patient, without regard for long term results or the economic situation as it affects both patient and hospital services. In the context of surgical treatment which is now available, it is suggested that the advantages of operation over other therapies presage a reversion to surgery as the treatment of choice.

The influence of preoperative drug treatment on the histological appearances and in vitro 131I uptake of human hyperplastic thyroid gland.

The specimen of thyroid resected at partial thyroidectomy from 103 patients with primary thyrotoxicosis was studied with histometric and organ culture techniques. Twenty-seven patients had been prepared for operation with propranolol and seventy-six with carbimazole: all received Lugol's iodine for 10 days before operation. The resected specimen and deduced total thyroid weight was greater in the patients prepared with carbimazole. There was no absolute qualitative histopathological difference in the appearance of the glands of the two groups of patients, but histometry showed that the volume percentage of colloid and total gland colloid weight was significantly greater in the patients prepared with carbimazole: the volume percentage of epithelial cells and the total gland epithelial cell weight was similar in the two groups. The iodide concentrating capacity per g wet weight thyroid tissue or per unit volume of colloid did not differ significantly between the two groups. However, the iodide concentration capacity per unit volume of epithelial cells was significantly higher in the carbimazole prepared patients than in those prepared with propranolol.