bluuebunny/crossref_metadata_2025 huggingface dataset:
Testing the MODIS satellite retrieval of aerosol fine‐mode fraction
Authors: Anderson Theodore L. , Wu Yonghua , Chu D. Allen , Schmid Beat , Redemann Jens , Dubovik Oleg
Published: September 2005

Satellite retrievals of the fine‐mode fraction (FMF) of midvisible aerosol optical depth, τ, are potentially valuable for constraining chemical transport models and for assessing the global distribution of anthropogenic aerosols. Here we compare satellite retrievals of FMF from the Moderate Resolution Imaging Spectroradiometer (MODIS) to suborbital data on the submicrometer fraction (SMF) of τ. SMF is a closely related parameter that is directly measurable by in situ techniques. The primary suborbital method uses in situ profiling of SMF combined with airborne Sun photometry both to validate the in situ estimate of ambient extinction and to take into account the aerosol above the highest flight level. This method is independent of the satellite retrieval and has well‐known accuracy but entails considerable logistical and technical difficulties. An alternate method uses Sun photometer measurements near the surface and an empirical relation between SMF and the Ångström exponent, å, a measure of the wavelength dependence of optical depth or extinction. Eleven primary and fifteen alternate comparisons are examined involving varying mixtures of dust, sea salt, and pollution in the vicinity of Korea and Japan. MODIS ocean retrievals of FMF are shown to be systematically higher than suborbital estimates of SMF by about 0.2. The most significant cause of this discrepancy involves the relationship between å and fine‐mode partitioning; in situ measurements indicate a systematically different relationship from what is assumed in the satellite retrievals. Based on these findings, we recommend: (1) satellite programs should concentrate on retrieving and validating å since an excellent validation program is in place for doing this, and (2) suborbital measurements should be used to derive relationships between å and fine‐mode partitioning to allow interpretation of the satellite data in terms of fine‐mode aerosol optical depth.
Computer simulations of the translocation and unfolding of a protein pulled mechanically through a pore
Authors: Huang Lei , Kirmizialtin Serdal , Makarov Dmitrii E.
Published: September 2005

Protein degradation by ATP-dependent proteases and protein import into the mitochondrial matrix involve the unfolding of proteins upon their passing through narrow constrictions. It has been hypothesized that the cellular machinery accomplishes protein unfolding by pulling mechanically at one end of the polypeptide chain. Here, we use Langevin dynamics simulations of a minimalist off-lattice model to examine this hypothesis and to study the unfolding of a protein domain pulled mechanically through a long narrow pore. We compute the potential of mean force (PMF) experienced by the domain as a function of its displacement along the pore and identify the unfolding intermediates corresponding to the local minima of the PMF. The observed unfolding mechanism is different from that found when the two termini are pulled apart, as in single-molecule mechanical unfolding experiments. It depends on the pore diameter, the magnitude of the pulling force, and on whether the force is applied at the N- or the C-terminus of the chain. Consequently, the translocation time exhibits a pulling force dependence that is more complex than a simple exponential function expected on the basis of simple phenomenological models of translocation.
Simple controlled heating method for a free-standing sample using bimetallic strips
Authors: Narushima Tetsuya , Kinahan Niall T. , Boland John J.
Published: September 2005

We describe a simple method to heat a free-standing sample such as a cantilever using bimetallic strips. The bimetallic strips are used to make controlled electrical contacts induced by radiative heating of the strips by a W filament. In order to improve the electrical contacts and have good reproducibility, a double looped spring design was employed. By using this method, we can heat-up free-standing samples to 1400K. In addition, by using multiple bimetallic strips with the double looped spring designs, regional heating of the sample can be achieved.
Direct-current substrate bias effects on amorphous silicon sputter-deposited films for thin film transistor fabrication
Authors: Jun Seung-Ik , Rack Philip D. , McKnight Timothy E. , Melechko Anatoli V. , Simpson Michael L.
Published: September 2005

The effect that direct current (dc) substrate bias has on radio frequency-sputter-deposited amorphous silicon (a-Si) films has been investigated. The substrate bias produces a denser a-Si film with fewer defects compared to unbiased films. The reduced number of defects results in a higher resistivity because defect-mediated conduction paths are reduced. Thin film transistors (TFTs) that were completely sputter deposited were fabricated and characterized. The TFT with the biased a-Si film showed lower leakage (off-state) current, higher on/off current ratio, and higher transconductance (field effect mobility) than the TFT with the unbiased a-Si film.
Structure and ESCRT-III protein interactions of the MIT domain of human VPS4A
Authors: Scott Anna , Gaspar Jason , Stuchell-Brereton Melissa D. , Alam Steven L. , Skalicky Jack J. , Sundquist Wesley I.
Published: September 2005

The VPS4 AAA ATPases function both in endosomal vesicle formation and in the budding of many enveloped RNA viruses, including HIV-1. VPS4 proteins act by binding and catalyzing release of the membrane-associated ESCRT-III protein lattice, thereby allowing multiple rounds of protein sorting and vesicle formation. Here, we report the solution structure of the N-terminal VPS4A
m
icrotubule
i
nteracting and
t
ransport (MIT) domain and demonstrate that the VPS4A MIT domain binds the C-terminal half of the ESCRT-III protein, CHMP1B (
K
d
= 20 ± 13 μM). The MIT domain forms an asymmetric three-helix bundle that resembles the first three helices in a tetratricopeptide repeat (TPR) motif. Unusual interhelical interactions are mediated by a series of conserved aromatic residues that form coiled-coil interactions between the second two helices and also pack against the conserved alanines that interdigitate between the first two helices. Mutational analyses revealed that a conserved leucine residue (Leu-64) on the third helix that would normally bind the fourth helix in an extended TPR is used to bind CHMP1B, raising the possibility that ESCRT-III proteins may bind by completing the TPR motif.
Out-of-plane motions in open sliding clamps: Molecular dynamics simulations of eukaryotic and archaeal proliferating cell nuclear antigen
Authors: Kazmirski Steven L. , Zhao Yanxiang , Bowman Gregory D. , O'Donnell Mike , Kuriyan John
Published: September 2005

Sliding clamps are ring-like multimeric proteins that encircle duplex DNA and serve as mobile DNA-bound platforms that are essential for efficient DNA replication and repair. Sliding clamps are placed on DNA by clamp loader complexes, in which the clamp-interacting elements are organized in a right-handed spiral assembly. To understand how the flat, ring-like clamps might interact with the spiral interaction surface of the clamp loader complex, we have performed molecular dynamics simulations of sliding clamps (proliferating cell nuclear antigen from the budding yeast, humans, and an archaeal species) in which we have removed one of the three subunits so as to release the constraint of ring closure. The simulations reveal significant structural fluctuations corresponding to lateral opening and out-of-plane distortions of the clamp, which result principally from bending and twisting of the β-sheets that span the intermolecular interfaces, with smaller but similar contributions from β-sheets that span the intramolecular interfaces within each subunit. With the integrity of these β-sheets intact, the predominant fluctuations seen in the simulations are oscillations between lateral openings and right-handed spirals. The tendency for clamps to adopt a right-handed spiral conformation implies that once opened, the conformation of the clamp can easily match the spiraling of clamp loader subunits, a feature that is intrinsic to the recognition of DNA and subsequent hydrolysis of ATP by the clamp-bound clamp loader complex.
Blinking and nonradiant dark fraction of water-soluble quantum dots in aqueous solution
Authors: Yao Jie , Larson Daniel R. , Vishwasrao Harshad D. , Zipfel Warren R. , Webb Watt W.
Published: September 2005

Water-soluble quantum dots (qdots) are now being used in life sciences research to take advantage of their bright, easily excited fluorescence and high photostability. Although the frequent erratic blinking and substantial dark (never radiant) fractions that occur in all available qdots may interfere with many applications, these properties of individual particles in biological environments had not been fully evaluated. By labeling Qdot-streptavidin with organic dyes, we were able to distinguish individual dark and bright qdots and to observe blinking events as qdots freely diffused in aqueous solution. Bright fractions were measured by confocal fluorescence coincidence analysis (CFCA) and two-photon cross-correlation fluorescence correlation spectroscopy (FCS). The observed bright fractions of various preparations were proportional to the ensemble quantum yields (QYs), but the intrinsic brightness of individual qdots was found to be constant across samples with different QYs but the same emission wavelengths. Increasing qdots' illuminated dwell time by 10-fold during FCS did not change the fraction of apparently dark qdots but did increase the detected fraction of blinking qdots, suggesting that the dark population does not arise from millisecond blinking. Combining CFCA with wide-field imaging of arrays of qdots localized in dilute agarose gel, the blinking of qdots was measured across five orders of magnitude in time: ≈0.001-100 s. This research characterizes photophysical pathologies of qdots in biologically relevant environments rather than adhered on dielectric surfaces and describes methods that are useful for studying various bioapplicable nanoparticles.
Severe acute respiratory syndrome coronavirus-like virus in Chinese horseshoe bats
Authors: Lau Susanna K. P. , Woo Patrick C. Y. , Li Kenneth S. M. , Huang Yi , Tsoi Hoi-Wah , Wong Beatrice H. L. , Wong Samson S. Y. , Leung Suet-Yi , Chan Kwok-Hung , Yuen Kwok-Yung
Published: September 2005

Although the finding of severe acute respiratory syndrome coronavirus (SARS-CoV) in caged palm civets from live animal markets in China has provided evidence for interspecies transmission in the genesis of the SARS epidemic, subsequent studies suggested that the civet may have served only as an amplification host for SARS-CoV. In a surveillance study for CoV in noncaged animals from the wild areas of the Hong Kong Special Administration Region, we identified a CoV closely related to SARS-CoV (bat-SARS-CoV) from 23 (39%) of 59 anal swabs of wild Chinese horseshoe bats (
Rhinolophus sinicus
) by using RT-PCR. Sequencing and analysis of three bat-SARS-CoV genomes from samples collected at different dates showed that bat-SARS-CoV is closely related to SARS-CoV from humans and civets. Phylogenetic analysis showed that bat-SARS-CoV formed a distinct cluster with SARS-CoV as group 2b CoV, distantly related to known group 2 CoV. Most differences between the bat-SARS-CoV and SARS-CoV genomes were observed in the spike genes, ORF 3 and ORF 8, which are the regions where most variations also were observed between human and civet SARS-CoV genomes. In addition, the presence of a 29-bp insertion in ORF 8 of bat-SARS-CoV genome, not in most human SARS-CoV genomes, suggests that it has a common ancestor with civet SARS-CoV. Antibody against recombinant bat-SARS-CoV nucleocapsid protein was detected in 84% of Chinese horseshoe bats by using an enzyme immunoassay. Neutralizing antibody to human SARS-CoV also was detected in bats with lower viral loads. Precautions should be exercised in the handling of these animals.
Studies of the toxicity of copper to pigs
Authors: Suttle N. F. , Mills C. F.
Published: September 2005

1. Six groups of four litter-mate female Large White pigs of about 17 kg live weight were allocated according to a 2×2 factorial design in each of two experiments in which rations containing 0 or 750 ppm copper were offered with either 0 and 500 ppm zinc, or 0 and 750 ppm iron. 2. Severity of toxicosis was assessed by determining aspartate transaminase activity in serum, observing the incidence of jaundice and determining the hemoglobin concentration in whole blood and Cu concentration in serum and liver. 3. Addition of 750 ppm Cu to the diet caused toxicity in nine out of twelve animals; it was most severe after about 4 weeks when two-to five-fold increases in serum Cu and aspartate transaminase levels were found and seven pigs were jaundiced. Serum Cu and aspartate transaminase concentrations and degrees of jaundice were apparently interrelated and returned to normal levels after 6 weeks, suggesting adaptation to the high Cu intake. Growth depression and a microcytic hypochromic anaemia persisted. 4. Addition of 500 ppm Zn or 750 ppm Fe in the presence of 750 ppm Cu eliminated jaundice and produced serum Cu and aspartate transaminase concentrations similar to control values after 4 weeks. Only supplementary Fe afforded protection against anaemia. 5. Variability in the response of the pig to Cu supplements could be partly due to variations in the intake of Fe and Zn. The addition of Fe and Zn supplements to pig diets supplemented with Cu would probably reduce the small risk of causing Cu poisoning.
Studies of the toxicity of copper to pigs
Authors: Suttle N. F. , Mills C. F.
Published: September 2005

1. Six groups of three (Expt 1) or four (Expt 2) female litter-mate Large White pigs were allocated after weaning to three or four treatments in a randomized block design. 2. In Expt 1, 600ppm copper were added to diets based on maize meal and containing either soya-bean meal, dried skim milk or white-fish meal to provide 16% total crude protein. Severity of Cu toxicosis was assessed by estimating aspartate transaminase (AST) activity in serum, Cu levels in serum and liver, haemoglobin concentration and the incidence of jaundice. 3. Toxicosis was severe only in pigs receiving white-fish meal, but liver Cu and haemoglobin levels were similar in all groups. 4. In Expt 2, 0, 250 or 425 ppm Cu or 425 ppm Cu+150 ppm zinc+150 ppm iron were added to the maize-white-fish meal diet from which the normal Zn and Fe supplements were omitted, creating optimal conditions for development of Cu toxicosis. 5. In the absence of Zn and Fe supplements, 425 ppm Cu caused the development of a severe toxicosis. Simultaneous addition of Zn and Fe supplements eliminated all signs of toxicosis. 6. Under the same conditions 250 ppm Cu caused a mild toxicosis and also exaggerated the slight signs of parakeratosis or Zn deficiency noted in control animals. 7. High calcium levels of 1.7% in a basal diet containing 30 ppm Zn probably induced a marginal Zn deficiency which favoured the development of Cu toxicosis. Differences in calcium level were probably responsible for the apparent effects of the different protein supplements in Expt 1. 8. Occasional occurrences of toxicity in pigs given 250 ppm Cu as a growth stimulant may be partly due to the use of diets low in Zn and Fe and high in calcium. Correcting these factors would extend the safety of Cu supplementation of the commercial diets.
Factors affecting the voluntary intake of food by cows
Authors: Campling R. C. , Freer M.
Published: September 2005

1. Two experiments were conducted to examine the effect of grinding and pelleting roughages on the voluntary intake of food, digestibility, time of retention of food in the digestive tract, amounts of digesta in the recitulo-rumen and eating and ruminating behaviour of adult, non-lactating, non-pregnant cows. The first experiment was with artificially dried grass and the second with oat straw; also, with a diet of ground, pelleted oat straw the effect was studied of giving a daily intraruminal infusion of 150 g urea. The size of the particles of the ground roughages are given. 2. The mean voluntary intakes of long and ground dried grass were similar, the voluntary intake of ground, pelleted oat straw was 26% greater than that of long straw and the daily infusion of urea increased the voluntary intake of ground, pelleted oat straw by 53%. 3. The digestibility of the ground roughages was lower than that of the long roughages, the lower digestibility of the ground roughages was due mainly to the poor digestibility of crude fibre in the reticulo-rumen. The rate of disappearance of cotton thread placed in the ventral sac of the rumen was slower with ground than with long roughages. 4. The mean times of retention of ground roughages were shorter than those of long roughages when equal and restricted amounts of each food were given; with food offered ad lib. there was little difference between the mean times of retention of long and ground roughages in the alimentary tract. 5. On average, the mean amounts of digesta dry matter in the reticulo-rumen immediately after a meal were about the same with long and ground dried grass, with long and ground oat straw the amounts of dry matter were similar, but when the intraruminal infusion of urea was given the amount of dry matter increased by 49%. 6. The rate of eating (min/kg food) ground, pelleted roughages was much faster than that with long roughages; when the cows received ground roughage rumination did not occur but during short periods triple reticular contractions were seen. 7. The relationship between the voluntary intake of food, the amount of digesta in the reticulo-rumen and the rate of disappearance of digesta from the alimentary tract is discussed.
The proteases, amylase and lipase of the pancreas and intestinal contents of germ-free and conventional rats
Authors: Lepkovsky S. , Furuta F. , Ozone K. , Koike T. , Wagner M.
Published: September 2005

1. Measurements were made of the proteases, amylase and lipase of the pancreas and of the corresponding intestinal, caecal and colonic contents of germ-free and conventional rats. 2. Little difference was found between the concentration of the enzymes in the germ-free and conventional rats. 3. The results indicate that intestinal bacteria had only a minor part in determining the fate of the pancreatic enzymes in the contents of the intestine, caecum and colon. 4. The enzyme concentrations decreased caudally. The proteases were the most stable, and the amylase was the least stable; the stability of lipase was intermediate between that of the proteases and amylase. 5. Evidence of bacterial activity in the caecal contents of conventional rats was seen in the greater percentage of protein nitrogen and in the lower percentage of the non-protein nitrogen
Evaluation of American and British rations for growing pigs
Authors: Barber R. S. , Braude R. , Hosking Zena D. , Mitchell K. G. , Bruner W. H. , Cahill V. R. , Gilliland J. J. , Gundlach R. F. , Teague H. S.
Published: September 2005

1. A test was carried out simultaneously in Shinfield, Reading, England, and Columbus, Ohio, USA, using typical British and American rations for growing pigs. The rations were compounded in their country of origin; half of each consignment was used at the home station and the other half shipped to the overseas station. 2. Both restricted feeding and ad lib. feeding methods were used at each station. 3. A similar pattern of results was obtained at Shinfield and Columbus. Pigs receiving the American ration, which was higher in energy content, grew faster and required less feed per kg live-weight gain than pigs receiving the British ration. The higher energy content of the ration was probably responsible also for the poorer carcass quality of the pigs receiving the American ration, particularly the high fat content. The comparison between restricted feeding and ad lib. feeding was not affected by the type of ration. Restricted feeding resulted in slower growth rate, slightly better efficiency of feed conversion and considerably better carcass quality.
The extent of differences between six British breeds of sheep in their metabolism, feed intake and utilization, and resistance to climatic stress
Authors: Blaxter K. L. , Clapperton J. L. , Wainman F. W.
Published: September 2005

1. Thirty wether sheep comprising five of each of the following breeds, Scottish Blackface, Welsh Mountain, Cheviot, Suffolk Down, Kent and Hampshire Down, were subjected to a standard series of experiments in which energy metabolism was measured during fasting and at the maintenance level of nutrition, and in which maximal voluntary intake of food was measured and the metabolic responses to the stress of wind (10 miles/h) and rain (1 cm/h) were determined. 2. The weight of an individual sheep at the maintenance level of feeding was 8.4% greater and when given feed ad lib. 22% greater than its weight when fasted. These increases largely reflected changes in the weight of gut contents. 3. When fasting metabolism was expressed per kg weight raised to the power 0.73, the small Welsh Mountain sheep had the lowest metabolism of 54.1 kcal/kg W0.73 and the Cheviot sheep the highest of 64.4 kcal/kg W0.73. Overall breed differences were statistically significant (0.05 > P > 0.01). Evidence collected in the experiments, however, suggests that fasting metabolism was more closely related to body-weight raised to the power 0.85. When this basis for breed comparison was used, differences in fasting metabolism between breed groups disappeared. 4. No differences between breed groups in the proportion of the energy they ingested which was lost in faeces, in urine or as methane, were found when they were given food at a maintenance level. The Welsh Mountain sheep, however, had the smallest heat production at the maintenance level when expressed as kcal/kg W0.73. 5. No differences between breed groups in the apparent digestibility of the energy of feed given ad lib. were found. The voluntary intake increased with weight of sheep. When the amount of feed energy consumed and the energy apparently digested were related to the determined maintenance requirement for apparently digested energy of each sheep, no differences between breed groups were found. The efficiency of feed utilization by these breed groups of sheep when given feed ad lib. was the same. 6. It was found that the Hampshire sheep were the most resistant to the effect of wind on their heat production, and the Welsh Mountain sheep the least. The Scottish Blackface was most resistant to the effect of rain on heat production. 7. It is concluded that metabolic differences between different breeds of sheep differing widely in size are quite small, but that breeds differ markedly in their resistance to environmental stresses caused by wind and rain, and that these largely reflect the characteristic fleece types of the breeds concerned.
The effect of differing high-carbohydrate diets on dental caries in the albino rat
Authors: Green R. M. , Hartles R. L.
Published: September 2005

1. Fifty-six albino rats were distributed between four dietary groups in fourteen randomized blocks of four animals. Each block consisted of siblings and each member of the block received a different dietary treatment. 2. The diets permitted normal growth and the only variations were: group I contained 67% sucrose, group 2 an equivalent amount of uncooked maize starch and groups 3 and 467 % of finely ground Thin Wine and Morning Coffee biscuits respectively. 3. After 31 days on the diet, the animals were killed and assessed for dental caries. The rats of group I had significantly more caries than the other groups. The rats of group 2 had significantly less caries than the other groups. The biscuit diets produced significantly less caries than the sucrose diet, but significantly more caries than the starch diet.
Some effects of dietary dextrose, fructose, liquid glucose and sucrose in the adult male rat
Authors: Allen R. J. L. , Leahy J. S.
Published: September 2005

1. For 26 weeks, adult male rats were fed on diets containing about 80 % of carbohydrate, given as dextrose, fructose, liquid glucose, or sucrose; their performance was compared with that of rats receiving a standard laboratory cubed diet (41 B) containing 60 % of carbohydrate, mainly as starch. 2. More of diet 41 B was eaten than of any of the diets containing sugars, but only with dextrose was the mean body-weight gain significantly lower than with diet 41 B. 3. No significant differences in body length or girth were produced by the different diets. 4. Compared with those of rats given diet 41B, plasma cholesterol levels were significantly in- creased by fructose and sucrose and to a lesser extent by dextrose, but not by liquid glucose. 5. Compared with those given diet 41 B, the rats given fructose had heavier hearts, kidneys and livers, those given sucrose had heavier hearts and livers, and those given dextrose had heavier hearts. Those given fructose had the heaviest kidneys and livers, and heavier hearts than those given liquid glucose. The organ weights of those given liquid glucose and those given diet 41 B were not significantly different. 6. Compared with the values on diet 41B, carcass and liver fat were both significantly increased by sucrose and fructose but not by dex- trose or liquid glucose. With fructose, liver fat was almost double that with dextrose or liquid glucose. 7. Dry-matter contents of whole carcass and liver followed substantially the same pattern as did the fat contents. 8. Liver protein content was significantly lower on the 80 % carbohydrate diets. The reductions were greatest with fructose and sucrose.
The intake and excretion of calorific constituents of milk by babies
Authors: Southgate D. A. T. , Barrett Irene M.
Published: September 2005

1. The intake and excretion of energy, total nitrogen, fat and carbohydrate by twenty baby boys aged about a fortnight were measured over 3 days. 2. Ten of the babies received breast milk which had been expressed from their mothers, the remaining ten received one of two preparations based on dried cow's milk, with either lactose or sucrose added. 3. The intake of energy, protein and carbohydrate was greater in the ten babies receiving the cow's milk preparations. 4. The urinary excretion and retention of N was greater in the babies fed on the cow's milk preparations. 5. The absolute excretion of N in the faeces was simiIar whatever the diet, but the excretion of fat was less and the excretion of carbohydrate greater for babies having breast milk. 6. The calorie:N ratio in the urine was 5.8 kcal/g urinary N in those receiving breast milk and 4.8 kcal/g N in those fed on the cow's milk preparations. The value for the adult is 7.9. 7. Calorie conversion factors have been calculated which are more appropriate for milk diets for babies than the factors of Atwater which were designed for mixed diets for adults.
Comparative studies on the digestive physiology of sheep fed on semi-purified or roughage-concentrate diets
Authors: Giesecke D. , Lawlor M. J. , Walser-KÄrst Karin
Published: September 2005

1. In a study of the microbial population in the rumen contents of sheep fed on a semipurified or a roughage-concentrate diet, the total counts and morphological groups of bacteria and protozoa, the counts of proteolytic, amylolytic and cellulolytic bacteria and the rates of breakdown of cellulose and starch in vitro were determined. Three sheep received each diet. 2. Protozoa disappeared completely from the rumen of sheep fed on the semi-purified diet. High counts of Entodinia persisted in the rumen of two sheep on the roughage-concentrate diet; a third animal was maintained defaunated on this diet. 3. The mean total counts of bacteria per g of rumen contents were 5 x 1010and 2.5 x 1010respectively in sheep fed on the semi-purified and roughage-concentrate diets and 11.4 x 1010in the defaunated sheep. 4. The proportions of the morphological groups of bacteria and the counts of amylolytic bacteria were similar with both diets; the mean counts of proteolytic and cellulolytic bacteria were twice as high in the sheep on the semi-purified diet. The counts of all three functional groups of bacteria were considerably higher in the single defaunated sheep. 5. The mean rates of cellulose breakdown were 16.6 and 9.5 g/l. rumen fluid per 24 h for the sheep fed on the semi-purified and roughage-concentrate diets respectively. The corresponding rates of starch fermentation were 28 and 42.4 g/l. rumen fluid per 24 h. 6. It is concluded that the bacterial population in the rumen of sheep fed on the semi-purified and the roughage-concentrate diets differed quantitatively rather than qualitatively. It is also concluded that the absence of protozoa, rather than a direct nutritive effect of the semi-purified diet, was responsible for the increased bacterial population in the rumen of the sheep fed on the semi-purified diet. The much higher bacterial counts in the rumen of the defaunated sheep support this view.
Measurement of fat thickness in man: a comparison of ultrasound, Harpenden calipers and electrical conductivity
Authors: Booth R. A. D , Goddard B. A. , Paton A.
Published: September 2005

1. Subcutaneous fat thickness has been measured by three different techniques in forty-one subjects. 2. Ultrasound provided the most accurate measurement in experienced hands. 3. A method based on electrical conductivity was also accurate but was unpleasant for the subject. 4. Harpenden calipers were the least satisfactory of the three techniques tested.
The effect of reproduction on the interaction of dietary protein and calcium
Authors: El-Maraghi N. R. H. , Plantt B. S. , Stewart R. J. C.
Published: September 2005

1. Rats were maintained from the age of 3 weeks until the end of a second reproductive cycle on diets having different protein values and Ca concentrations. 2. Reproductive performance was judged from the number of viable young, their size, body composition and rate of growth during suckling. 3. The size and quality of the bones of the mothers and offspring were assessed from radiographs, histological appearance, total weight of ash, ash/cm3and ash:organic matter ratios of dry fat-free bone. 4. At the end of gestation the mean numbers and total weights of foetuses were low when the mothers had received diets of low protein value: there were smaller differences in the body-weight, water, ash and N contents of the individual foetuses. 5. When 0.44% Ca was included in the diet of low protein value, only one (three rats) of the six litters born survived beyond 1 week of age. 6. At weaning, the young born of and suckled by the protein-calorie deficient dams were only about half the weight of those from mothers receiving the high-protein diets; Ca deficiency produced relatively minor changes. 7. All the mothers lost weight during lactation irrespective of the protein value or Ca concentration of the diet; their bones had lower radiographic densities and less ash/cm3than is usual in non-pregnant rats of similar age. 8. The interaction of protein and Ca and their relative importance in maintaining the skeletal structure of mother and offspring during pregnancy and lactation are discussed.
Diurnal variations in the excretion of faeces and urine by sheep fed once daily or at hourly intervals
Authors: Minson D. J. , Cowper J. L.
Published: September 2005

1. A machine is described which automatically releases previously weighed rations to individually penned sheep at hourly intervals for 24 h. 2. Six sheep were kept in a room with constant light, temperature and continuous background noise and given 912 g lucerne daily at 10.00 h or at hourly intervals by means of the automatic feeder. Faeces and urine were collected every 2 h. 3. Hourly feedings reduced the variation between 2-hourly collection periods by 47, 87, 90, 85, 70 and 91% for total dry-matter content of the faeces, faeces dry-matter concentration, total urine output, urine specific gravity, urine nitrogen concentration and total N content of the urine respectively.
The apparent retention of food in the reticulo-rumen at two levels of feeding by means of an hourly feeding technique
Authors: Minson D. J.
Published: September 2005

1. Sheep fitted with rumen cannulas were fed at hourly intervals by an automatic feeder in a controlled environment and the contents of the reticulo-rumen were removed at intervals of 6 h, 30 min after the previous feed. 2. No diurnal variation was found in the total contents or in the quantity of dry matter, organic matter and nitrogen. 3. Nine dried pasture herbages containing 0.79–3.69% N in dry matter were given automatically at a high and a low level of feeding. Feeding at the high level increased the total weight of the reticulo-rumen contents, total dry matter, organic matter and N and also the dry-matter percentage. 4. Apparent retention times were calculated by dividing the quantity of organic matter or N in the rumen by the quantity given each hour. Organic matter was retained for 10.2–24.9 h and N for 12.0–61.4 h. 5. The apparent retention times for both organic matter and N were reduced when the level of feeding was raised.
The protein requirement of infants at the age of about 1 year
Authors: Chan H. , Waterlow J. C.
Published: September 2005

1. A study has been made of the protein requirements for maintenance and for growth of children about 1 year old who had recovered from malnutrition. 2. The diets used supplied 120kcal/kg daily; the sole source of protein was dried skim milk. 3. The average maintenance requirement, measured by nitrogen balance, was found to be 100 mg N/kg day. At this level of intake the net protein utilization (NPU) of cow's milk protein approached 100. 4. An intake of 200 mg N/kg day was enough to produce normal growth and N retention. 5. The amount of N retained was 2.9 g/100 g weight gain, indicating that no excess of fat was being laid down. 6. These results are in close agreement with theoretical studies of the protein requirement of children at this age.
Assessment of sugar intake: validity of the questionnaire method
Authors: Yudkin John , Roddy Janet
Published: September 2005

1. Assessment of sugar intake by our short questionnaire has been shown to agree well with its assessment by the conventional method in which subjects keep a 7-day diary of their diets. 2. People who have had a myocardial infarct, or are suffering from peripheral vascular disease, tend to reduce their intake of sugar. We believe this is the reason why investigators making dietary studies several months, or years, after infarction have not found the relatively high sugar consumption in patients with infarction that we had reported earlier. 3. The most suitable method for ascertaining dietary intake depends both on the constituent or constituents to be examined, and on the purpose of the investigation.
Methionine deficiency and iron retention in the rat
Authors: Kaufman Nathan , Klavins Janis V. , Kinney Thomas D.
Published: September 2005

1. Methionine-deficient diets were given to rats for 4 weeks. 2. This resulted in a decrease in total body iron, due to a decrease either in Fe absorption or Fe retention. 3. There was inhibition of growth, development of anaemia and a shift of body Fe to the liver. 4. There were no histological alterations which could be interpreted as specific to methionine deficiency. 5. These findings were different from reports of effects of ethionine in which there is an increased Fe absorption and various tissue alterations, including pancreatic acinar and liver damage.
Blood glucose, lactate and pyruvate in kwashiorkor
Authors: Whitehead R. G. , Harland P. S. E. G.
Published: September 2005

1. The blood sugar, lactate and pyruvate levels of sixty-nine Ugandan children, during treatment for kwashiorkor, have been studied. 2. The majority of untreated cases had low levels of blood glucose but high levels of lactate and pyruvate. Children with the lowest glucose levels had the lowest serum protein values and gained weight more slowly. 3. The response of the blood glucose to glucagon or adrenaline was twice as great at the end of treatment as at the beginning. 4. In children whose treatment was successful the lactate and pyruvate levels gradually fell to the normal range. There was a rise in the blood glucose value but after 3 weeks the level was still below that found in normal African children. In a few children who died or whose treatment was complicated by pyrexia and general apathy there was a rapid fall in lactate and pyruvate concentration to abnormally low levels.
Biological evaluation of crab meat (Scylla-Serrata)in the rat
Authors: Gangal S. V. , Magar N. G.
Published: September 2005

1. The meat of the Indian species of crab was assessed for the quality of its protein with the use of protein-depleted adult rats.

2. The crab meat and casein had the same biological value, 88.

3. Crab meat supported a higher growth rate than casein in rats.
Studies of amino acid requirements of adult rats
Authors: Smith Elizabeth B. , Johnson B. C.
Published: September 2005

1. A series of experiments was carried out to determine the minimum essential amino acid requirements of the adult rat.

2. After testing four amino acid patterns taken from the literature, a basal pattern was formulated in which each amino acid appeared at the lowest level at which it was presented in any of the original diets.

3. Nitrogen balance was the main criterion used to judge any benefit arising from modest increases in individual amino acids tested in a modified Latin-square design. They were given at a protein level of 3.6% of the diet. Non-essential amino acids were in the same proportions as in whole egg.

4. It appeared that three amino acids, namely tryptophan, threonine and isoleucine, brought about more favourable balances when presented at concentrations higher than basal.

5. Reduced levels of each amino acid were then tested in order to ensure that no surpluses were present.

6. N retentions indicated that lysine, phenylalanine plus tyrosine, leucine and valine could be reduced below the basal level and still meet the needs of the rat for these amino acids.

7. When the pattern of amino acids arising from these latter trials was tested in combination, rather than as trios, pairs, or single changes, positive N balances gave confidence that these were minimal levels of the essential amino acids required for meeting the maintenance needs of adult rats.

8. Plasma proteins from the rats on the evolved pattern were found to be in no way different from those found for normal animals. This gave further support to the belief that the pattern was adequate for the rats.
Vitamin E and stress
Authors: Diplock A. T. , Bunyan J. , Mchale D. , Green J.
Published: September 2005

1. The metabolism of small amounts of [5-Me-14C]D-α-tocopherol and [5-Me-3H]D-α- tocopherol has been studied in the vitamin E-deficient chick. Small doses of the labelled tocopherol were given to chicks, which were then subjected to stress by giving them diets formulated to produce encephalomalacia, exudative diathesis or muscular dystrophy.

2. Tocopherol concentrations in the cerebella and brains of chicks with incipient encephalomacia were the same as those in normal chicks in which the dietary fat stress was absent.

3. α-Tocopherol delayed the onset of encephalomalacia by a mean value of 3.5 days when its concentration in the cerebellum was about 2 × 10−7g/g of lipid. This concentration is considerably below the usual effective concentrations of antioxidants in vitro.

4. Selenium deficiency, under conditions leading to a high incidence of exudative diathesis, was not associated with lowered tocopherol levels and did not result in detectable destruction of tocopherol.

5. Nor was there any destruction of tocopherol or significant effect on its metabolism in the processes leading to muscular dystrophy: on the contrary, the affected muscles of dystrophic chicks, which had received a diet deficient in sulphur amino acids, contained significantly more tocopherol than muscles from control birds.

6. These results do not support the hypothesis that lipid peroxidation is a causative process in the aetiology of vitamin E-deficiency diseases in the chick. The relationships between unsaturated lipid, Se, sulphur amino acids and tocopherol in the chick require further exploration.
Vitamin E and stress
Authors: Diplock A. T. , Green J. , Bunyan J. , Mchale D. , Muthy I. R.
Published: September 2005

1. When weanling rats were given a vitamin E-deficient diet and 0.15% (w/v) silver acetate in their drinking water, there was a high incidence of liver necrosis and death after 2–4 weeks. This was prevented by 120 ppm D-α-tocopheryl acetate in the diet, was partially prevented by selenium at 1 ppm but not at 0.05 ppm and was only marginally prevented by 0.15% DL-methionhe.

2. All these effects were observed when the diet was free of fat and when it contained either methyl oleate or polyunsaturated methyl esters. The polyunsaturated lipid slightly increased the velocity of the terminal illness.

3. In spite of the ‘anti-vitamin E’ effect of Ag and the clear demonstration that α-tocopherol played a major part in preventing toxicity, experiments with tracer amounts of [5-Me-14C]-D-α-tocopherol showed that rather than there being any destruction of tocopherol in the critical period preceding the onset of disease, there was an increase in tocopherol in the liver due to Ag administation. The metabolism of tocopherol in the remainder of the animal was unaffected during the pre-necrotic phase.

4. The results are inconsistent with the view that the stress induced by Ag is caused by a pro-oxidant effect, either in the gastro-intestinal tract or in the tissues of the rat. They show that lipid peroxidation is not a causal factor in the aetiology of Ag-induced liver necrosis and suggest that stress in the vitamin E-deficient animal probably raises the requirement for tocopherol.
Lysosomal enzymes and vitamin E deficiency
Authors: Bunyan J. , Green J. , Diplock A. T. , Robinson D.
Published: September 2005

1. The activities of several lysosomal hydrolases were measured in the tissues of chicks suffering from nutritional muscular dystrophy, encephalomalacia or exudative diathesis.

2. In dystrophic breast muscle, β-glucuronidase was raised five- to six-fold, cathepsin fourfold and acid phosphatase 1.5-fold. No change was found in the subcellular distribution of β-glucuronidase.

3. Chicks with encephalomalacia showed no changes in the β-glucuronidase, β-galactosidase, acid phosphatase or β-acetylglucosaminase activities of cerebellum or brain. Subcellular distribution of β-glucuronidase and β-galactosidase in these tissues was also unchanged.

4. In exudative diathesis, hydrolases were found in the exudate, and there was increased activity in the subcutaneous tissue first showing haemorrhages. Increased hydrolytic activity was found in liver, spleen and kidney. Breast muscle was not always affected by the exudative condition, but, when it too degenerated, its hydrolase activity increased.

5. β-Glucuronidase activity was measured in the serums of chicks suffering from each of the three deficiency diseases. None of the diseases caused a rise in activity.
Lysosomal enzymes and vitamin E deficiency
Authors: Bunyan J. , Green J. , Diplock A. T. , Robinson D.
Published: September 2005

1. Activities of β-glucuronidase, β-galactosidase, acid phosphatase and cathepsin were measured in the uterine contents of normal rats during gestation and of vitamin E-deficient rats during foetal resorption.

2. β-Glucuronidase activity reached a peak value on days 11 and 12, falling to lower values by day 14. Deficient rats showed slightly greater mean values than normal rats on days 11 and 12, but not after that time.

3. Vitamin E deficiency did not affect the activities of β-galactosidase, acid phosphatase and cathepsin, all of which showed a slow decrease during pregnancy.

4. The supernatant fraction of homogenates of uterine contents from deficient rats showed increased β-glucuronidase and β-galactosidase activity from day 14 to 17, suggesting some degree of rupture of the lysosomal membrane.

5. β-Glucuronidase and acid phosphatase activities were raised in the uteruses of some deficient rats towards the end of pregnancy, but serum β-glucuronidase was unaffected.

6. Changes in lysosomal hydrolases were not so marked during gestation–resorption as in some other vitamin E deficiency states, such as muscular dystrophy in the chick and rabbit.
Effect of dietary protein level and thyroxine on vitamin A absorption and on plasma proteins in chicks
Authors: Nir I. , Ascarelli I.
Published: September 2005

1. The effect of dietary protein level and supplementation with thyroxine on the liver storage of vitamin A, on the fraction of liver vitamin A in the alcohol form, and on the plasma levels of vitamin A and proteins has been studied in chicks.

2. Liver storage was reduced by lowering the dietary protein level.

3. Protein restriction lowered the percentage of vitamin A found in the liver as retinol.

4. Thyroxine increased both vitamin A storage and the fraction of the total vitamin A as retinol, this effect being dependent on dietary protein level.

5. Plasma vitamin A and plasma protein contents were lowered to a highly significant extent by protein restriction. This drop was essentially caused by reduction of the albumin fraction in chicks fed on a 5% protein diet and by a reduction of β- and γ-globulins in chicks fed on a 10% protein diet.

6. Thyroxine supplementation of the diet lowered to a highly significant extent plasma protein content; this reduction was caused by a dramatic fall in the level of plasma albumin. The β- and γ-globulins were concomitantly increased.
The effect of the type of roughage in the diet on plasma cholesterol levels and aortic atherosis in rabbits
Authors: Moore J. H.
Published: September 2005

1. Eleven groups of male rabbits (eight to eleven per group) were given adlib. a diet consisting of 61 parts of a low-fat basal ration to which were added: for groups 1–3, 20 parts maize oil; for groups 4–7, 20 parts butterfat; and for groups 8–11, 0.47 parts maize oil and 43.1 parts wheat starch. Different types of roughage were added to the 61 parts of basal ration as follows: for groups 1, 4 and 8, 19 parts ground wheat straw; for groups 2, 5 and 9, 19 parts Solkafioc; for groups 3, 6 and 10, 19 parts of shredded cellophane; and for groups 7 and 11, 14 parts shredded cellophane and 5 parts peat.

2. After the rabbits had been given the experimental diets for a period of 40 weeks, the plasma cholesterol levels were determined. The animals were then killed and the degree of atheromatous degeneration was determined after the aortas had been stained with Sudan IV.

3. Elevated levels of plasma cholesterol and extensive atheromatous degeneration were observed in the rabbits given the diets containing 20% butterfat (groups 4–7) and in those given the diets containing 48% starch (groups 8–11). Lower levels of plasma cholesterol and only slight atheromatous degeneration were observed in the rabbits given the diets containing 20% maize oil (groups 1–3).

4. The levels of plasma cholesterol and the degree of aortic atherosis were influenced very markedly by the nature of the dietary roughage. Plasma cholesterol levels and degrees of aortic atherosis tended to be higher when cellophane was the roughage component than when wheat straw was the roughage component of the diet. The replacement of part of the cellophane of the diet by peat reduced the level of plasma cholesterol and the degree of aortic atherosis.

5. The possible mechanisms by which the nature of the dietary roughage influences plasma cholesterol levels are discussed.