The human chromosome 11q13 (HSA 11q13) genomic locus is a major cancer hotspot and has been established as the most frequently altered by amplification in a variety of human cancers. The fatty acid desaturase genes (FADS1, FADS2 and FADS3) localize to the 11q12- 13.1 region. FADS2 activity is promiscuous, catalyzing biosynthesis of polyunsaturated and monounsaturated fatty acids, including unsaturated branched chain fatty acids (BCFA) by Δ6, Δ8, and Δ4 desaturation toward at least 16 substrates. Our main aim here is to review known and putative consequences of FADS2 dysregulation due to effects on the 11q13 locus in various cancer types. We searched PubMed and Google Scholar databases for articles that showed 11q13 amplification and studies reporting FADS2 function in various cancer types. FADS2 silencing causes synthesis of sciadonic acid (ScA, 5Z,11Z,14Z-20:3) in MCF7 cells and breast cancer in vivo. 5Z,11Z,14Z-20:3 is structurally identical to the eicosanoid precursor arachidonic acid (5Z,8Z,11Z,14Z–20:4) except it lacks the internal Δ8 double bond required for prostaglandin and leukotriene synthesis, among other eicosanoids. Melanoma, prostate, liver and lung cancer cells insensitive to SCD inhibition show increased FADS2 activity leading to sapienic acid (16:1n10) biosynthesis from 16:0. Elevated serum mead acid (20:3n-9) levels were found in more than a third of hepatocellular carcinoma patients, indicative of an unsatisfied demand for arachidonic acid, likely as a substrate for eicosanoids. A highly expressed circular RNA (hsa_circ_022382) within an exonic region of FADS2 is associated with shorter overall survival in colorectal cancer patients. Similarly, in lung cancer tissues circFADS2 RNA is highly expressed. Palmitic acid (16:0) is a common substrate for SCD and FADS2. FADS2 circular RNAs are at high levels in colorectal and lung cancer tissues. The evidence thusfar supports an effort for future research on the role of FADS2 as a tumor suppressor in a range of neoplastic disorders.

This study suggests a novel cooperative multi-simplex algorithm that generalizes a local search optimizer to design a novel global search heuristic algorithm. The proposed algorithm exploits the vertex sharing strategy to enhance the search abilities of the working simplexes. The vertex sharing among the simplexes is carried out through cooperative step that is based on fitness of the underlying simplex. The proposed algorithm is applied to solve some systems of nonlinear equations by transforming them to optimization problems. Comparative analysis of results shows that the proposed method is practical and effective.

Synchronous homopolar machines (SHM) with excitation winding on the stator have attracted the attention of researchers for many decades due to their high reliability. They are used in a variety of applications such as aircraft and railway generators and traction motors. At the same time, the three-dimensional structure of their magnetic circuit makes the problem of their analysis and optimization challenging. This problem becomes even more complicated when considering an SHM with hybrid excitation, with ferrite magnets in the rotor slots. The article proposes a mathematical procedure for optimizing a synchronous homopolar generator with hybrid excitation based on the single-criterion Nelder-Mead method and two-dimensional finite element analysis (FEA). The use of the Nelder-Mead method compared to multicriteria methods and 2D FEA compared to 3D FEA makes possible to significantly reduce the computational burden. As a result of optimization, the power loss and torque ripples of the generator are significantly reduced. The article also compares the characteristics of synchronous homopolar generators with and without ferrite magnets.