Application of variational approach to non-Newtonian fluid flow modelling

The generalized Lagrange variational principle for the analysis of boundary-value problem of non- Newtonian fluid flow is specified. Based on generalized Euler-Lagrange equations it is demonstrated that the generalized Lagrange variational principle is equivalent to the boundary-value problem for the vorticity transport equation. An asymptotic case, namely a problem of a non-Newtonian fluid flow in a thin layer between two parallel plates, is studied to verify this, and the results match the analytical results

Synthesis, X-ray structure and biological activity of mono- and dinuclear copper complexes derived from N-{2-[(2-diethylamino(alkyl)imino)-methyl]-phenyl}-4-methyl-benzenesulfonamide

A series of copper(II) complexes with new Schiff bases, namely N-{2-[(2-diethylamino(alkyl)imino)-methyl]-phenyl}-4-methylbenzenesulfonamide [alkyl = ethyl (HL1) or propyl (HL2)], were synthesized using copper acetate or chloride and characterized by elemental analysis, IR and X-ray absorption spectroscopy, and single-crystal X-ray diffraction. The coordination geometry around the Cu(II) ion in Cu(L1)2 and Cu(L2)2 was studied by X-ray absorption spectroscopy. The crystal structures of copper(II) complexes with L1 ligand synthesized from copper chloride and copper acetate with addition of sodium azide have been determined by X-ray diffraction. The azomethines and all copper(II) complexes have been screened for their antibacterial, protistocidal, and fungistatic activities against Penicillium italicum, Colpoda steinii, Escherichia coli 078, and Staphylococcus aureus P-209. © 2021 Elsevier B.V

Analysis of Multiple Drug Resistance Mechanism in Different Types of Soft Tissue Sarcomas: Assessment of the Expression of ABC-Transporters, MVP, YB-1, and Analysis of Their Correlation with Chemosensitivity of Cancer Cells

Chemotherapy of soft tissue sarcomas (STS) is restricted by low chemosensitivity and multiple drug resistance (MDR). The purpose of our study was the analysis of MDR mechanism in different types of STS. We assessed the expression of ABC-transporters, MVP, YB-1, and analyzed their correlation with chemosensitivity of cancer cells. STS specimens were obtained from 70 patients without metastatic disease (2018–2020). Expression level of MDR-associated genes was estimated by qRT-PCR and cytofluorimetry. Mutations in ABC-transporter genes were captured by exome sequencing. Chemosensitivity (SI) of STS to doxorubicin (Dox), ifosfamide (Ifo), gemcitabine (Gem), and docetaxel (Doc) was analyzed in vitro. We found strong correlation in ABCB1, ABCC1, and ABCG2 expression. We demonstrated strong negative correlations in ABCB1 and ABCG2 expression with SI (Doc) and SI (Doc + Gem), and positive correlation of MVP expression with SI (Doc) and SI (Doc + Gem) in undifferentiated pleomorphic sarcoma. Pgp expression was shown in 5 out of 44 STS samples with prevalence of synovial sarcoma relapses and it is strongly correlated with SI (Gem). Mutations in MDR-associated genes were rarely found. Overall, STS demonstrated high heterogeneity in chemosensitivity that makes reasonable in vitro chemosensitivity testing to improve personalized STS therapy, and classic ABC-transporters are not obviously involved in MDR appearance. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Soft Tissue Sarcoma Study: Association of Genetic Alterations in the Apoptosis Pathways with Chemoresistance to Doxorubicin

Soft tissue sarcomas (STS) are heterogeneous cancers with more than 100 histological subtypes, different in molecular alterations, which make its personalized therapy very complex. Gold standard of chemotherapy for advanced STS includes combinations of Doxorubicin and Ifosfamide or Gemcitabine and Docetaxel. Chemotherapy is efficient for less than 50% of patients and it is followed by a fast development of drug resistance. Our study was directed to the search of genetic alterations in cancer cells associated with chemoresistance of undifferentiated pleomorphic and synovial sarcomas to the abovementioned genotoxic drugs. We analyzed chemoresistance of cancer cells in vitro using primary STS cultures and performed genetic analysis for the components of apoptotic signaling. In 27% of tumors, we revealed alterations in TP53, ATM, PIK3CB, PIK3R1, NTRK1, and CSF2RB. Cells from STS specimens with found genetic alterations were resistant to Dox, excluding the only one case when TP53 mutation resulted in the substitution Leu344Arg associated with partial oligomerization loss and did not cause total loss of TP53 function. Significant association between alterations in the components of apoptosis signaling and chemoresistance to Dox was found. Our data are important to elaborate further the therapeutic strategy for STS patients with alterations in apoptotic signaling. © 2022 by the authors. Licensee MDPI, Basel, Switzerland