Epstein-Barr virus genomes in undifferentiated and squamous cell nasopharyngeal carcinomas in Italian patients

Three antigens of Candida albicans were comparatively evaluated to their ability to elicit delayed hypersensitivity (DH) responses in the mouse footpad test, using alloxan-diabetic and normal mice which were primed with heat-killed C. albicans in complete Freund adjuvant. These antigens were: (1) a preparation of sonically disrupted heat-killed cells; (2) a preparation of soluble cytoplasmic material remaining in the supernatant of a broken-cell suspension centrifuged at 100,000 g; (3) a preparation obtained by extraction of pulverized defatted cells with dilute phenol and sodium bicarbonate in water. After separation by polyacrylamide gel electrophoresis, the major components of soluble cytoplasmic material and dilute phenol extract were identified as a 43-kD protein, and glycoproteins of 21, 27 and 38 kD, respectively. Fifty-eight CD-1 outbred mice, which had received a single intravenous injection of alloxan followed by a 28-day rest period, were randomized with normal littermates to distinct experimental groups. Seven days after sensitization, mice were injected with one of the antigens in the right rear footpad and saline in the left rear footpad and the net specific increase in footpad thickness determined 24 and 48 h later. All three antigens elicited significant responses in sensitized normal mice. The responses of sensitized diabetic mice were clearly inferior to those of sensitized normal mice when heat-killed cells and soluble cytoplasmic material were used. Dilute phenol extract elicited equivalent responses at 24 and 48 h in both primed diabetic and normal mice.     

Discretization errors in numerical micromagnetic models

Numerical micromagnetic models attempt to determine coercive force, reversal modes, the number of stable magnetic states of particles, and the effect of particle interaction. These models can have considerable discretization error. In some cases, the calculated equilibrium states change considerably when the number of elements is increased. An analysis of three types of discretization errors suggests a measure of the accuracy of the models     

Theoretical aspects of demagnetization tensors

A magnetometric demagnetization tensor is defined for uniformly-magnetized samples of arbitrary geometry. It is shown that this is a real symmetric tensor with non-negative diagonal elements and unit trace. Diagonalization of the magnetometric demagnetization tensor yields the Brown-Morrish equivalent ellipsoid and the conclusion that Stoner-Wohlfarth particles of any surface geometry have only two easy directions of magnetization. Transformation of the tensor, subject to periodicity constraints, leads to the conclusion that uniformly-magnetized samples with rotational periodicity, of ordern geq 3about a single axis, have isotropic behavior perpendicular to that axis. It is also shown that if a sample has spherical periodicity with four or more vertices it does not exhibit shape anisotropy. Various methods for determining the numerical values of the tensor elements are presented.     

Lowpass filter with minimum integrated power-loss ratio in the passband

A class of lowpass filters with minimum integrated power-loss ratio in the passband is discussed. Comparisons with the usual Butterworth and Cheby?shev filters are also reported.     

Microbiological, physicochemical, and sensory characteristics of kefir during storage

Changes in certain microbiological, physicochemical, and sensory parameters of kefir were studied during refrigerated storage. Kefir batches were prepared using 1% and 5% added kefir grains, and samples for analysis were taken 24 h after inoculation and then after 2, 7, 14, 21, and 28 days of storage at 5 ± 1 °C. After fermentation for 24 h after inoculation, lactobacilli and lactococci were present at levels of 10⁸ cfu/ml, and yeasts and acetic acid bacteria were present at levels of 10⁵ and 10⁶ cfu/ml, respectively. The lactic acid flora decreased by about 1.5 log units between days 7 and 14 and then stabilized at that level. Yeast and acetic acid bacterial counts, lactose, and pH all remained constant over the storage period, while the total fat content and dry matter decreased. The percentage inoculate did exert an influence, and the sample batches made using 1% added kefir grains had higher lactic acid bacterial counts, lactose, and pH, while the sample batches made using 5% added kefir grains had higher yeast and acetic acid bacterial counts and viscosity. The total fat and dry matter contents were similar in both sample batches. Sensory analysis of the kefir samples revealed maximum acceptability levels in the first 2 days of storage.     

Bacteriocinogenic activity from starter cultures used in Spanish meat industry

Thirty-nine bacterial strains, obtained from commercial starter cultures and commonly used by the meat industry in Spain, have been examined for their ability to produce bacteriocins. Fourteen (35%) of them showed antagonism against at least one of the indicator strains, by the agar spot test. The strains showing an inhibitory action against pathogenic indicator strains were identified as Pediococcus acidilactici, Lactobacillus curvatus, Lactobacillus pentosus and Lactobacillus plantarum, which showed an inhibitory action against a wide range of Gram-positive bacteria. The only strain which showed reliable inhibitory activity against pathogenic indicator strains, by the well diffusion assay, was P. acidilactici. This strain produces an inhibitory compound, which reaches its maximum activity at the beginning of the stationary phase of growth. This antimicrobial substance (bacteriocin) has a proteinaceous nature, is stable over a broad range of pH, resistant to heat and shows a bactericidal action.