The key genes involved in the development of esophageal squamous cell carcinoma (ESCC) remain to be elucidated. Previous studies indicate extensive genomic alterations occur on chromosome 9 in ESCC. Using a monochromosome transfer approach, this study provides functional evidence and narrows down the critical region (CR) responsible for chromosome 9 tumor suppressing activity to a 2.4 Mb region mapping to 9q33-q34 between markers D9S1798 and D9S61. Interestingly, a high prevalence of allelic loss in this CR is also observed in primary ESCC tumors by microsatellite typing. Allelic loss is found in 30/ 34 (88%) tumors and the loss of heterozygosity (LOH) frequency ranges from 67 to 86%. Absent to low expression of a 9q32 candidate tumor suppressor gene (TSG), DEC1 (deleted in esophageal cancer 1), is detected in four Asian ESCC cell lines. Stably expressing DEC1 transfectants provide functional evidence for inhibition of tumor growth in nude mice and DEC1 expression is decreased in tumor segregants arising after long-term selection in vivo. There is 74% LOH in the DEC1 region of ESCC primary tumors. This study provides the first functional evidence for the presence of critical tumor suppressive regions on 9q33-q34. DEC1 is a candidate TSG that may be involved in ESCC development.

The partition monoid is a salient natural example of a *-regular semigroup. We find a Galois connection between elements of the partition monoid and binary relations, and use it to show that the partition monoid contains copies of the semigroup of transformations and the symmetric and dual-symmetric inverse semigroups on the underlying set. We characterize the divisibility preorders and the natural order on the (straight) partition monoid, using certain graphical structures associated with each element. This gives a simpler characterization of Green's relations. We also derive a new interpretation of the natural order on the transformation semigroup. The results are also used to describe the ideal lattices of the straight and twisted partition monoids and the Brauer monoid.2010 Mathematics subject classification: primary 20M20; secondary 20M17, 05A18, 06A15. Keywords and phrases: partition monoid, Brauer monoid, ideal structure, natural order. Diagrams and productsPartition algebras, which are twisted semigroup algebras of the partition monoids, are important in the theory of group representations, combinatorics, and statistical mechanics, and have an extensive literature including significant studies in [7,13,14]. Generators and relations for partition monoids have been studied in [3], and their endomorphisms in [15]. Wilcox [20, Section 7] studied the structure of the partition monoid in an application of his quite general theorem about the cellularity of twisted semigroup algebras of regular semigroups. It is our intention to investigate the structure of partition monoids further. We use this first section to describe the elements of the partition monoid P X and their multiplication, and to draw attention to some of the subsemigroups of P X which are interesting in their own right.Let X be a set. A diagram over X is an equivalence class of graphs on a vertex set X ∪ X (consisting of two copies of X ). Two such graphs are regarded as equivalent if they have the same connected components. We define P X as the set of all diagrams over X . Also, if X is finite, say X = {1, 2, . . . , n}, we conventionally write P n in place of P X , and similarly for other families of semigroups.

The generators of the Temperley-Lieb algebra generate a monoid with an appealing geometric representation. It has been much studied, notably by Louis Kau¤man. Borisavljević, Došen and Petrić gave a complete proof of its abstract presentation by generators and relations, and suggested the name 'Kau¤man monoid'. We bring the theory of semigroups to the study of a certain …nite homomorphic image of the Kau¤man monoid. We show the homomorphic image (the Jones monoid ) to be a combinatorial and regular *-semigroup with linearly ordered ideals. The Kau¤man monoid is explicitly described in terms of the Jones monoid and a purely combinatorial numerical function. We use this to describe the ideal structure of the Kau¤man monoid and two other of its homomorphic images.

We present the molecular structure of the IsiA-Photosystem I (PSI) supercomplex, inferred from high-resolution, crystal structures of PSI and the CP43 protein. The structure of iron-stress-induced A protein (IsiA) is similar to that of CP43, albeit with the difference that IsiA is associated with 15 chlorophylls (Chls), one more than previously assumed. The membrane-spanning helices of IsiA contain hydrophilic residues many of which bind Chl. The optimal structure of the IsiA-PSI supercomplex was inferred by systematically rearranging the IsiA monomers and PSI trimer in relation to each other. For each of the 6,969,600 structural configurations considered, we counted the number of optimal Chl-Chl connections (i.e., cases where Chl-bound Mg atoms are