Let E be a Banach space over C and let the densely defined closed linear operator A: D(A) ... EQ E be discretely approximated by the sequence ((An, D(An)))n ¥N of operators An where each An is densely defined in the Banach space Fn. Let sa(A) be the approximate point spectrum of A and let se(An) denote the e-pseudospectrum of An. Generalizing our own result, we show that sa(A) ... lim inf se(An...

Activated killer (AK) cells cytotoxic for freshly prepared autologous melanoma cells were generated in vitro when recombinant interleukin 2 (rIL2) was incubated with peripheral blood mononuclear cells from 11 of 12 patients with metastatic melanoma. The cytotoxic response first appeared significant after 3 days of culture with rIL2; it peaked after 6 days and then declined after 9 days of incub...

Site-directed mutagenesis in vitro was used to introduce stop codons in the genomic DNA of the alpha and beta chains of the murine class II major histocompatibility complex antigen, I-Ak. Mutated DNA was transfected into B lymphoma cells that were then selected by neomycin resistance and for their ability to express I-Ak molecules on their plasma membrane. The translational diffusion coefficien...

We examined the structural characteristics of a peptide Ag that determine its ability to interact with class II-MHC molecules and TCR. The studies reported here focused on recognition of the hen egg white lysozyme (HEL) tryptic fragment HEL(34-45) by two I-Ak-restricted T cell hybridomas. HEL(34-45) bound to I-Ak created more than one antigenic specificity. Experiments with truncated peptides a...

BACKGROUND Cutaneous human papillomavirus (HPV) infections seem to be associated with the onset of actinic keratosis (AK). This study compares the presence of cutaneous HPV types in eyebrow hairs to those in tissues of normal skin and skin lesions of 75 immunocompetent AK patients. METHODS Biopsies from AK lesions, normal skin and plucked eyebrow hairs were collected from each patient. DNA fr...

R. L. Bentzen (correspondence), Dept. of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK 99775 7220, USA. E-mail: [email protected]. A. N. Powell, Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK 99775 7000, USA and U. S. Geological Survey, Alaska Cooperative Fish and Wildlife Research Unit, University of Alaska Fairbanks, Fairbanks, AK 99775-7020, USA....

Let G be a group given by the presentation 〈a1, . . . , ak , b1, . . . bk | ai = ui(b̄), bi = vi(ā) for 1 ≤ i ≤ k〉, where k ≥ 2 and where the ui ∈ F (b1, . . . , bk) and wi ∈ F (a1, . . . , ak) are random words. Generically such a group is a small cancellation group and it is clear that (a1, . . . , ak) and (b1, . . . , bk) are generating n-tuples for G. We prove for generic choices of u1, . . ....

The set G(B) of invertible elements of B is the main example of a regularity. As was proved in [4], the set of elements of B which are not topological zero divisors is also a regularity. In the present paper, we investigate a construction of joint spectra in B by means of regularities in B. Let σ(a)= {μ∈ C | a−μe ∈G(B)} be the ordinary spectrum in B. Recall that according to the terminology int...

To identify which polymorphic residues determine the allospecific antibody binding sites on A beta polypeptides, mutant Ak beta genes were constructed encoding single or multiple amino acids of the d allele at 14 polymorphic positions in the beta 1 domain. Cell lines expressing these genes were analyzed by quantitative immunofluorescence using 16 mAbs reactive to Ak beta or Ad beta. Substitutio...

Use of reliable density maps is crucial for rapid and successful crystal structure determination. Here, the averaged kick (AK) map approach is investigated, its application is generalized and it is compared with other map-calculation methods. AK maps are the sum of a series of kick maps, where each kick map is calculated from atomic coordinates modified by random shifts. As such, they are a num...