let r be an associative ring with unity. an element a in r is said to be r-clean if a = e+r, where e is an idempotent and r is a regular (von neumann) element in r. if every element of r is r-clean, then r is called an r-clean ring. in this paper, we prove that the concepts of clean ring and r-clean ring are equivalent for abelian rings. further we prove that if 0 and 1 are the only idempotents...

Introduction Tumour-reactive T cells producing the B-cell attractant chemokine CXCL13, in solid tumours, promote development of tertiary lymphoid structures (TLS) and are associated with improved prognosis responsiveness to checkpoint immunotherapy. Cancer fibroblasts dominant stromal cell type non-small lung cancer (NSCLC) where they co-localise can influence activation exhaustion. We question...

We describe the case of an intrabronchial aspirated foreign body that caused a persistent right lower lobe infiltrate. A first fibreoptic bronchoscopy demonstrated a mass with tumour-like appearance in the right bronchus intermedias, but the bronchial biopsies and the cytological smears of the bronchial aspirate failed to reveal any malignancy. During a control fibreoptic bronchoscopy, we found...

A ring of 8-15 identical c-subunits is essential for ion-translocation by the rotary electromotor of the ubiquitous F(O)F(1)-ATPase. Here we present the crystal structure at 3.4Å resolution of the c-ring from chloroplasts of a higher plant (Pisum sativum), determined using a native preparation. The crystal structure was found to resemble that of an (ancestral) cyanobacterium. Using elastic netw...

in this work, we investigate the transfer of some homological properties from a ring $r$ to its amalgamated duplication along some ideal $i$ of $r$ $rbowtie i$, and then generate new and original families of rings with these properties.

for a ring endomorphism $alpha$ and an $alpha$-derivation $delta$, we introduce a concept, so called skew $pi$-armendariz ring, that is a generalization of both $pi$-armendariz rings, and $(alpha,delta)$-compatible skew armendariz rings. we first observe the basic properties of skew $pi$-armendariz rings, and extend the class of skew $pi$-armendariz rings through various ring extensions. we nex...

In the years after Edward O. Wilson and Robert MacArthur’s seminal book, The Theory of Island Biogeography (1), which laid the foundations for understanding species diversity and extinction rates in isolated habitats, was published in 1967, a flurry of papers erupted on the effect of fragmentation in tropical rainforests. The big question at that time was whether it would be more advisable to p...