Chrisimos: A useful Proof-of-Work for finding Minimal Dominating Set of a graph

Hash-based Proof-of-Work (PoW) used in the Bitcoin Blockchain leads to high energy consumption and resource wastage. In this paper, we aim to re-purpose the energy by replacing the hash function with real-life problems having commercial utility. We propose Chrisimos, a useful Proof-of-Work where miners are required to find a minimal dominating set for real-life graph instances. A miner who is able to output the smallest dominating set for the given graph within the block interval time wins the mining game. We also propose a new chain selection rule that ensures the security of the scheme. Thus our protocol also realizes a decentralized minimal dominating set solver for any graph instance. We provide formal proof of correctness and show via experimental results that the block interval time is within feasible bounds of hash-based PoW.Comment: 20 pages, 3 figures. An abridged version of the paper got accepted in The International Symposium on Intelligent and Trustworthy Computing, Communications, and Networking (ITCCN-2023) held in conjunction with the 22nd IEEE International Conference on Trust, Security and Privacy in Computing and Communications (TrustCom-2023

Hematopoietic stem cells and retroviral infection

Retroviral induced malignancies serve as ideal models to help us better understand the molecular mechanisms associated with the initiation and progression of leukemogenesis. Numerous retroviruses including AEV, FLV, M-MuLV and HTLV-1 have the ability to infect hematopoietic stem and progenitor cells, resulting in the deregulation of normal hematopoiesis and the development of leukemia/lymphoma. Research over the last few decades has elucidated similarities between retroviral-induced leukemogenesis, initiated by deregulation of innate hematopoietic stem cell traits, and the cancer stem cell hypothesis. Ongoing research in some of these models may provide a better understanding of the processes of normal hematopoiesis and cancer stem cells. Research on retroviral induced leukemias and lymphomas may identify the molecular events which trigger the initial cellular transformation and subsequent maintenance of hematologic malignancies, including the generation of cancer stem cells. This review focuses on the role of retroviral infection in hematopoietic stem cells and the initiation, maintenance and progression of hematological malignancies

Equations of Rounded-Edge Profile for a Ring Gear in a Wave Reducer with Intermediate Rolling Elements

The paper considers geometrical parameters of a ring gear for a wave gear with rolling elements. A coordinate system is selected. Parametric equations for the ring gear profile are deduced. An equation for rounded edges of the ring gear is developed to increase the transmission efficiency and shorten the ring gear's running-in period. An epicycloidal ring gear profile is plotted in AutoCad. A sample model produced from these calculations is shown. The product is intended for use in the design of a hand-held electric drill on the base of a commutator motor with useful capacity of 1 kW

Profil ekspresije receptora hormona rasta (GHR), receptora čimbenika rasta sličnog inzulinu (IGFR) i gena leptina s biokemijskim i endokrinim profilom u jaradi crne bengalske koze (Capra hircus) tijekom različitih razdoblja pretpubertetskog rasta

The aim of this study was to evaluate the expression profile of growth hormone receptor (GHR), insulin like growth factor receptor (IGFR) and leptin genes, together with some blood biochemical (glucose, aspartate aminotransferase, AST; alanine aminotransferase, ALT) and endocrine (growth hormone and cortisol) parameters. For this purpose, blood samples were collected from 25 male and 25 female kids of the Black Bengal goat (Capra hircus), at days 15, 30, 60, 90, 120 and 150. Male kids gained more body weight compared to females. The glucose and cortisol levels significantly (P≤0.01) decreased with the advancement of age. AST, ALT, and growth hormone increased significantly (P≤0.01). In both sexes, plasma glucose level was negatively (P≤0.01) correlated with AST. In males both cortisol and GH levels were positively (P≤0.05) correlated with plasma glucose levels. In female kids only GH showed a positive (P≤0.05) correlation with glucose levels. Female kids had greater expression of the GH receptor, IGFR mRNA and Leptin mRNA on day 30 (P≤0.05) and day 150 (P≤0.01). GHR was only positively (P≤0.05) correlated with IGFR and LEP in female kids. On the basis of the results obtained from our research, we are able to conclude that the lower growth rate in female kids expressed more leptin, which stimulated the somatotrophic axis for the expression of GHR and IGFR during the prepubertal growth stage.Cilj istraživanja bio je procijeniti profil ekspresije receptora hormona rasta (GHR), receptora čimbenika rasta sličnog inzulinu (IGFR) i gena leptina zajedno s krvnim biokemijskim pokazateljima (glukoza, aspartat-aminotransferaza AST, alanin-aminotransferaza ALT) i endokrinim pokazateljima (hormon rasta i kortizol). U tu su svrhu 15., 30., 60., 90., 120. i 150. dan života uzeti su uzorci krvi od 25 muške i 25 ženske jaradi crne bengalske koze (Capra hircus). Muška je jarad imala veći prirast tjelesne mase u usporedbi sa ženskom. Razine glukoze i kortizola s porastom dobi znakovito su se smanjivale (P ≤ 0,01). AST, ALT i hormon rasta znakovito su porasli (P ≤ 0,01). Kod oba je spola razina glukoze u plazmi bila u negativnoj korelaciji (P ≤ 0,01) s AST-om. Kod muške su jaradi kortizol i hormon rasta bili u pozitivnoj korelaciji (P ≤ 0,05) s razinama glukoze u plazmi. Samo je u ženske jaradi hormon rasta pokazao pozitivnu korelaciju (P ≤ 0,05) s razinama glukoze. Ženska je jarad imala veću ekspresiju receptora hormona rasta, mRNA IGFR i mRNA leptina 30. dan (P ≤ 0,05) i 150. dan (P ≤ 0,01). GHR je bio u pozitivnoj korelaciji (P ≤ 0,05) samo s IGFR-om i leptinom u ženske jaradi. Na temelju rezultata ovoga istraživanja možemo zaključiti da niža stopa rasta u ženske jaradi dovela do veće ekspresije leptina, što je stimuliralo somatotropnu os za ekspresiju hormona rasta i IGFR-a u pretpubertetskom razdoblju