Gardner Transition in Physical Dimensions.

The Gardner transition is the transition that at mean-field level separates a stable glass phase from a marginally stable phase. This transition has similarities with the de Almeida-Thouless transition of spin glasses. We have studied a well-understood problem, that of disks moving in a narrow channel, which shows many features usually associated with the Gardner transition. We show that some of these features are artifacts that arise when a disk escapes its local cage during the quench to higher densities. There is evidence that the Gardner transition becomes an avoided transition, in that the correlation length becomes quite large, of order 15 particle diameters, even in our quasi-one-dimensional system.

Functional integration of new neurons into hippocampal networks and poststroke comorbidities following neonatal stroke in mice.

Stroke in the developing brain is an important cause of chronic neurological morbidities including neurobehavioral dysfunction and epilepsy. Here, we describe a mouse model of neonatal stroke resulting from unilateral carotid ligation that results in acute seizures, long-term hyperactivity, spontaneous lateralized circling behavior, impaired cognitive function, and epilepsy. Exploration-dependent induction of the immediate early gene Arc (activity-regulated cytoskeleton associated protein) in hippocampal neurons was examined in the general population of neurons versus neurons that were generated approximately 1 week after the ischemic insult and labeled with bromodeoxyuridine. Although Arc was inducible in a network-specific manner after severe neonatal stroke, it was impaired, not only in the ipsilateral injured but also in the contralateral uninjured hippocampi when examined 6 months after the neonatal stroke. Severity of both the stroke injury and the acquired poststroke epilepsy negatively correlated with Arc induction and new neuron integration into functional circuits in the injured hippocampi.

An electron microscope study of the axonemal ultrastructure in human spermatozoa from male smokers and nonsmokers.

OBJECTIVE: To investigate possible abnormalities or deterioration of the sperm axonemal ultrastructure in men who have smoked a large quantity of cigarettes (> 20 per day) for a prolonged period. DESIGN: Semen specimens were collected by patients via masturbation; qualitative characteristics of the sperm were assessed and ultrastructural analysis of the sperm axoneme was performed using standard operating procedures for electron transmission microscopy. SETTING: The Andrology Institute of Lexington, Lexington, Kentucky, and the Department of Histology and Embryology, University of Salonika, Greece (collaborative effort). PATIENT(S): Twenty-nine men (mean age +/- SD, 30.7 +/- 2.1 years) who smoked a mean (+/- SD) of 30.7 +/- 2.1 cigarettes per day for 10.7 +/- 0.7 years and 15 men who never smoked (mean age +/- SD, 30.4 +/- 2.2 years) participated in this study. MAIN OUTCOME MEASURE(S): Ultrastructural organization of the sperm axoneme in male smokers and nonsmokers. RESULT(S): Changes in the number and the arrangement of axonemal microtubules were noted in the smoker group when compared to the nonsmoker group. The incidence of axonemal abnormalities was higher in spermatozoa from smokers compared with that in spermatozoa from nonsmokers. CONCLUSION(S): Smoking a large quantity of cigarettes per day, under the conditions of the current study, severely affected the ultrastructure of the flagellum and, more specifically, it affected the axoneme of the human spermatozoon.

Invariance of perceptual spaces and perceptual separability of stimulus dimensions.

This article reports an extension of a paradigm for studying processing of perceptual dimensions. The paradigm is the complete identification task with a feature-complete factorial design (FCFD) of stimuli providing data for multidimensional signal detection analyses. The extension uses blocks of trials with subsets of the FCFD stimulus set, allowing estimation of various d's for inferring perceptual separability (PS) of dimensions and for disambiguating stimulus configurations when PS fails. Results of 4 experiments found the following: PS of arc curvature and line orientation in a discrimination task (Experiment 1), increasing PS failure in detection of horizontal and vertical lines (Experiment 2a), 45 degrees and 135 degrees (Experiment 2b), and 50 degrees and 60 degrees oblique lines (Experiment 2c). In each experiment, corresponding d's remained equivalent across blocks with different stimulus subsets.

The influence of selection for response on repetition priming of word identification.

Repetition priming of word identification was examined using study tasks that required participants either to search for targets appearing in rapid serial visual presentation of word lists or to read aloud a list of target words. Nontarget words embedded in search lists produced a small amount of repetition priming on a masked word identification test, independent of presentation duration in the search list (200-1,000 ms), but no priming when they appeared as targets in a second search task used at test. For both test tasks, words that were originally encoded in a read-aloud task or served as detected targets during a search task generated more priming than nontarget words from search lists. These results suggest that priming effects are strongest when study tasks require an item to be selected as the basis for an overt response, even though the information on which study and test responses are based may be different.

Milk Iodine Content as Influenced by Feed Sources and Sanitizer Residues 1.

Human consumption of iodine has increased to amounts which are about equal to the upper safe level as set by the National Research Council. One of the major sources for the greater iodine consumption is an increase in the amount reported in milk and other dairy products. The mammary gland does not limit the amount of iodine secreted in milk as it does with many other elements. Increased use of organic iodine in feed has resulted in high levels in milk in some dairy herds. Most of the herds with levels above 1,000 µg/liter were fed organic iodine above recommended levels as a prevention for foot rot. Iodine teat dips and udder washes can contribute additional iodine to the milk. In a few instances, the misuse of iodine sanitizers in the dairy industry has also contributed to increased milk iodine. If milk iodine levels are to be held at the present level or decreased, iodine feed supplementation and sanitizers must be used as currently recommended.

Superoxide Dismutase Activity in Bovine Milk Serum.

Superoxide dismutase activity was shown to be present in bovine milk serum and was quantified by measuring the capacity of retentate from dialyzed milk serum to inhibit reduction of cytochrome c by xanthine-xanthine oxidase-generated superoxide anion. One unit of enzyme was defined as the quantity of superoxide dismutase which inhibits cytochrome c reduction by 20%. By this definition 19,500 units of enzyme were present per liter of retentate from dialyzed milk serum. This amount is equivalent to about 2.4 mg of purified bovine erythrocyte superoxide dismutase per liter. Polyacrylamide gel electrophoresis of a partially-purified superoxide dismutase from acid whey, followed by staining for enzymic activity, confirmed the presence of the enzyme in milk serum which was identical in electrophoretic properties to those of bovine erythrocyte copper-zinc superoxide dismutase. Pasteurization at 63 C for 30 min did not decrease superoxide dismutase activity in milk serum. Heating of purified bovine erythrocyte-superoxide dismutase at 100 C for 1 min resulted in almost complete loss of enzymic activity, whereas the partially-purified superoxide dismutase from acid whey still retained 40% of the original activity under these conditions. Bovine milk superoxide dismutase may be an important naturally-occurring antioxidant for increasing oxidative stability of milk and other dairy products.

Use of hydrolyzed whey peptide to inhibit culture agglutination.

Papain was used to hydrolyze sweet whey to prepare peptides that were harvested with ultrafiltration membranes (molecular weight cutoffs of 10,000, 3000, and 1000). Insure buffer salts were added to whey peptides (ratio 40:60% solids, respectively) to prepare media that were tested for their ability to inhibit culture agglutination. Commercial Insure medium (75.7 g/l) was used as a control. Skim milk (240 ml) in 250-ml graduated cylinders was inoculated (4%) with Lactococcus lactis spp. lactis B62 or E72. Culture agglutination was determined by measuring upper center and bottom pH values of the skim milk column during 5 h of incubation. A pH differential was calculated by subtracting the bottom pH from the upper center pH. Cultures grown in media containing whey peptides agglutinated in skim milk to a lesser degree than when grown in the control medium. Culture agglutination was inhibited to a greater degree when cultures were grown in the 1000 molecular weight cutoff peptide medium than when grown in the 10,000 or 3000 molecular weight cutoff peptide medium. When culture E72 was grown in medium containing 1000 molecular weight cutoff peptides, culture agglutination was completely inhibited.

Heat inactivation of superoxide dismutase in bovine milk.

Superoxide dismutase, and enzyme normal to bovine milk, may be inactivated partially by heat during processing of milk and milk products. A minimal pasteurization temperature (71.7 C for 15 s) does not cause heat inactivation of superoxide dismutase. Higher temperature of pasteurization or systems including a 'vac-heat process' will inactivate a substantial portion of the enzyme. Heat treatments greater than 75 C inactivated more than 20% of the superoxide dismutase. Purified superoxide dismutase fractionated from bovine milk was more sensitive to thermal processing than the superoxide dismutase in bovine milk serum.

Variation of Laboratory Cheesemaking Procedures.

The variability of yield for Cheddar cheese manufactured in 7- and 390-kg-size vats and cottage and direct-acid-set cheese manufactured in 7-kg-size vats was compared. The direct-acid-set cheese had less variability than Cheddar or cottage cheese (% coefficient of variation was .91, 1.79 and 4.69, respectively) manufactured in 7-kg-size vats and Cheddar cheese manufactured in 360-kg-size vats (% coefficient of variation was .91 and 1.98, respectively). Cottage cheese had the largest variability between replications using small vats because of additional stirring and curd manipulation required in its manufacture. Therefore, when cheese variety is of no concern, the direct-acid-set cheese procedure would reduce variation between replication more than traditional Cheddar procedures when used in an experimental design. In addition, a greater number of vats of cheese could be manufactured per day using the small vat system.

Psychrotrophic Bacteria Reduce Cheese Yield 1.

Psychrotrophic strains of Bacillus and Pseudomonas that demonstrated both proteolytic and lipolytic activity were incubated with Grade A milk. The yield of direct-acid cheese manufactured from inoculated milk decreased as psychrotrophic inoculation level increased. Yield reduction resulted from both lipid and protein degradation, and accounted for approximately 45 and 55% of the dry matter loss, respectively. Fat losses were observed from decreased milkfat tests and increased acid degree values. Protein losses were observed from increased non-protein nitrogen and whey nitrogen values. Therefore, cheese yield studies must involve assays of both protein and lipid on a dry matter basis. Acid degree values and fat disappearance in stored milk and total nitrogen in whey were the best indicators of reduction in yields. Although bacterial enumeration, titratable acidity and pH were not good indicators of yield, they may be important in determining when yield loss starts.

Effects of a supplemental liquid yeast product on feed intake, ruminal profiles, and yield, composition, and organoleptic characteristics of milk from lactating Holstein cows.

A liquid yeast product (about 11% DM), produced as a by-product of riboflavin synthesis, was incorporated into a TMR at three concentrations to determine the maximal inclusion rate and acceptability as a feed supplement in diets of lactating cows. Twelve Holstein cows in midlactation were randomly assigned to TMR treatments containing (as-fed basis) 1) no yeast product (control), 2) 20% dietary yeast product, or 3) 40% dietary yeast product in a 3 x 3 Latin square design with 3-wk periods. Dietary DM contents were 90, 74.2, and 58.4% for the 0, 20, and 40% yeast product TMR, respectively. The control TMR was based on a 45:55 ratio (DM basis) of mixed concentrate and chopped alfalfa hay. The DMI decreased linearly with increasing percentages of dietary yeast product. Milk yield and milk protein percentage were not altered by inclusion of the dietary yeast product. Milk fat tended to respond quadratically to increases in the percentage of dietary yeast product in the TMR. The supplemental dietary yeast product had no effect on ruminal pH; however, the ratio of acetate to propionate decreased, and propionate percentage tended to increase, as supplementation of the yeast product increased. Addition of yeast product to the TMR had no adverse effect on milk flavor. Milk from cows fed yeast product had better flavor than milk from control cows. Results indicate that inclusion of this yeast product at 40% depressed feed intake.

Nomenclature of the proteins of cows' milk--sixth revision.

This report of the American Dairy Science Association Committee on the Nomenclature, Classification, and Methodology of Milk Proteins reviews changes in the nomenclature of milk proteins necessitated by recent advances of our knowledge of milk proteins. Identification of major caseins and whey proteins continues to be based upon their primary structures. Nomenclature of the immunoglobulins consistent with new international standards has been developed, and all bovine immunoglobulins have been characterized at the molecular level. Other significant findings related to nomenclature and protein methodology are elucidation of several new genetic variants of the major milk proteins, establishment by sequencing techniques and sequence alignment of the bovine caseins and whey proteins as the reference point for the nomenclature of all homologous milk proteins, completion of crystallographic studies for major whey proteins, and advances in the study of lactoferrin, allowing it to be added to the list of fully characterized milk proteins.

C-cell hyperplasia, pheochromocytoma and sympathoadrenal malformation in a mouse model of multiple endocrine neoplasia type 2B.

Dominantly inherited multiple endocrine neoplasia type 2B (MEN2B) is characterized by tumors of the thyroid C-cells and adrenal chromaffin cells, together with ganglioneuromas of the gastrointestinal tract and other developmental abnormalities. Most cases are caused by substitution of threonine for Met918 in the RET receptor tyrosine kinase, which is believed to convert the RET gene to an oncogene by altering the enzyme's substrate specificity. We report the production of a mouse model of MEN2B by introduction of the corresponding mutation into the ret gene. Mutant mice displayed C-cell hyperplasia and chromaffin cell hyperplasia progressing to pheochromocytoma. Homozygotes did not develop gastrointestinal ganglioneuromas, but displayed ganglioneuromas of the adrenal medulla, enlargement of the associated sympathetic ganglia and a male reproductive defect. Surprisingly, homozygotes did not display any developmental defects attributable to a loss-of-function mutation. Thus, while our results support the conclusion that the Met918Thr substitution is responsible for MEN2B, they suggest that the substrate specificity of the RET kinase does not interfere with its normal role in the development of the kidneys and enteric nervous system.