Superconducting correlations in metallic nanoparticles: exact solution of the BCS model by the algebraic Bethe ansatz

Superconducting pairing of electrons in nanoscale metallic particles with discrete energy levels and a fixed number of electrons is described by the reduced BCS model Hamiltonian. We show that this model is integrable by the algebraic Bethe ansatz. The eigenstates, spectrum, conserved operators, integrals of motion, and norms of wave functions are obtained. Furthermore, the quantum inverse problem is solved, meaning that form factors and correlation functions can be explicitly evaluated. Closed form expressions are given for the form factors that describe superconducting pairing.Comment: revised version, 5 pages, revtex, no figure

Landscape of mutations in early stage primary cutaneous melanoma: An InterMEL study

It is unclear why some melanomas aggressively metastasize while others remain indolent. Available studies employing multi-omic profiling of melanomas are based on large primary or metastatic tumors. We examine the genomic landscape of early-stage melanomas diagnosed prior to the modern era of immunological treatments. Untreated cases with Stage II/III cutaneous melanoma were identified from institutions throughout the United States, Australia and Spain. FFPE tumor sections were profiled for mutation, methylation and microRNAs. Preliminary results from mutation profiling and clinical pathologic correlates show the distribution of four driver mutation sub-types: 31% BRAF; 18% NRAS; 21% NF1; 26% Triple Wild Type. BRAF mutant tumors had younger age at diagnosis, more associated nevi, more tumor infiltrating lymphocytes, and fewer thick tumors although at generally more advanced stage. NF1 mutant tumors were frequent on the head/neck in older patients with severe solar elastosis, thicker tumors but in earlier stages. Triple Wild Type tumors were predominantly male, frequently on the leg, with more perineural invasion. Mutations in TERT, TP53, CDKN2A and ARID2 were observed often, with TP53 mutations occurring particularly frequently in the NF1 sub-type. The InterMEL study will provide the most extensive multi-omic profiling of early-stage melanoma to date. Initial results demonstrate a nuanced understanding of the mutational and clinicopathological landscape of these early-stage tumors

Molecular disorders in transitional vs. peripheral zone prostate adenocarcinoma

Loss of heterozygosity (LOH) and microsatellite instability (MSI) have been shown to be mechanisms for tumor-suppressor gene inactivation in human oncogenesis. In our study, we examined LOH and MSI using 16 polymorphic markers of DNA for chromosomes 1, 3, 7, 8, 10 and 11. Microdissected tumor samples were isolated from 32 patients, representing 11 foci of incidentally discovered prostate cancer of the transitional zone (TZ), 12 prostate cancer of the peripheral zone (PZ) and 10 of high-grade PIN. We found loss of heterozygosity in the TZ group in 91% of informative cases (10/11) with al least 1 marker compared to 58% of cases (7/12) in PZ group and 70% of cases (7/10) in the HGPIN group. Chromosome 7 showed the highest rate of allelic loss in all 3 categories, with loss of 43% of loci in PIN, 37% in TZ tumors and 31% in PZ tumors. At chromosome 11, LOH was detected in 26% of loci in the TZ group, in 7% of loci in the PZ group and in 13% of loci in the PIN group. On chromosome 8, the PZ and HGPIN group showed allelic loss in 22% and 21% of loci, respectively, compared to 10% detected in the TZ group. The TZ group showed a significant higher rate of allelic instability compared to that observed in tumor samples from the peripheral zone: 73% of cases (8/11) showed genetic alterations (RER+ phenotype) in at least 4 loci analyzed compared to 8% and 10% in the PZ and HGPIN groups, respectively (p = 0.0006). These data suggest that transitional zone carcinoma and peripheral zone carcinoma display distinct and specific genetic alterations in different chromosomes. This diversity may help explain biologic and clinical differences between carcinomas arising in these distinct zones of the prostate. Also our results strongly suggest that the RER+ mutator phenotype could be linked to early development of transitional zone prostate carcinoma