The effect of thermal resistance of building’s opaque elements and windows surface on air exchange intensity during the summer season

The purpose of this work – connected with overheating process occurring in buildings – was to investigate the intensity of natural air exchange when a value of thermal resistant for outside walls is being increased together with the increase of the window’s surface. To obtain higher thermal resistant the outside partition were covered with insulating material subsequently from 3 to 30 cm. Window surface to wall surface ratio (wwr) was changing from 5% to 50%. The window’s test surface was facing east, south and west in turn while the wwr of the remaining orientations was kept at a constant 1/10 of the wall. The intensity of the buoyancy flux was analyzed as well. Three forms of ventilation airflow were considered – with assisting and opposing winds and no wind appearance. The process was examined in a single zone building, naturally ventilated, fitted with heat accumulating mass

Rapid decrease of CD16 (Fc\gammaRIII) expression on heat-shocked neutrophils and their recognition by macrophages

Accumulation of neutrophils in the site of inflammation is a typical mechanism of innate immunity. The accumulated neutrophils are exposed to stressogenic factors usually associated with inflammation. Here, we studied response of human peripheral blood neutrophils subjected to short, febrile-range heat stress. We show that 90 min heat stress slowed down the spontaneous apoptosis of neutrophils. In the absence of typical markers of apoptosis the heat-shocked neutrophils induced antiinflammatory effect in human monocyte-derived macrophages (hMDMs), yet without being engulfed. Importantly, the expression of Fc\gammaRIII (CD16) was sharply reduced. Surprisingly, concentration of the soluble CD16 did not change in heat-shocked neutrophil supernates indicating that the reduction of the cell surface CD16 was achieved mainly by inhibition of fresh CD16 delivery. Inhibitors of 90 kDa heat shock protein (HSP90), a molecular chaperone found in membrane platforms together with CD16 and CD11b, significantly increased the observed effects caused by heat shock. The presented data suggest a novel systemic aspect of increased temperature which relies on immediate modification by heat of a neutrophil molecular pattern. This effect precedes cell death and may be beneficial in the initial phase of inflammation providing a nonphlogistic signal to macrophages before it comes from apoptotic cells

Geochemistry and electron spin resonance of hydrothermal dickite (Nowa Ruda, Lower Silesia, Poland) : Vanadium and chromium

Geochemical analyses for trace V and Cr have been done on a representative sample of a typical hydrothermal dickite/kaolinite filling vein at Nowa Ruda. The mineralogy of the sample is comparatively simple, dickite being the principal component (ca. 91 % of the total sample). Geochemical fractionation and inductively coupled plasma-optical emission spectrometry (ICP-OES) indicate that most ( > 90 % of total metal) of the V and Cr reside in the dickite. Electron Spin Resonance (ESR) shows that most ( > 70 %) of the V in the dickite structure is in the form of vanadyl (VO2+) ions. A high concentration of Cr3+ is also detected in this structure by ESR. The combination of geochemical and spectroscopic tools applied to VO2+ and Cr3+ allow one to specify the Eh ( > 0.4 V, highly oxidizing) and pH ( 4.0, highly acidic) of the solution during the formation of dickite from the Nowa Ruda Basin. Substantial proportions of the V and Cr (as well as VO2+ and Cr3+) in the dickite structure were probably contained in an original hydrothermal acid water. We suggest that hot hydrothermal waters leached the surrounding varieties of gabbroids enriched in V and Cr for the dickite-forming solution. The results of this work have shown V and Cr are potentially reliable indicators for geochemical characterization of the physicochemical conditions of their formation. The bulk-rock V/Cr ratio in hydrothermal dickites and kaolinites from Nowa Ruda, Sonoma (California, USA), Cigar Lake (Saskatchewan, Canada) and Teslić (Bosnia and Hercegovina) is also briefly explored here as a potential tracer of redox state during their formation

9-Deazaguanine and Its Methyl Derivatives: Synthesis, Antitumor Activity in vitro and Effects on Purine Nucleoside Phosphorylase Gene Expression

9-Deazaguanine 9-DG, 1-methyl-9-deazaguanine AG-19-K1 and 1,7-dimethyl-9-deazaguanine AG-3 were synthesized and their antiproliferative activity against five leukemia and four solid tumor cell lines as well as inhibitory properties vs. calf spleen purine nucleoside phosphorylase (PNP) were tested. Synthesis of 9-DG involves reaction of 2-amino-6-methyl-5-nitropyrimidin- 4(3H)-one (2) with DMF-dimethylacetal (amount ratio, n(2) / n(DMF-dimethylacetal) = 1:2.5) and use of the benzyloxymethyl group to protect the N-3 position of 2-(N-dimethylaminomethylene) amino-6-methyl-5-nitropyrimidin-4(3H)-one (4). Reaction of 2 with DMF-dimethylacetal (amount ratio, n(2) / n(DMF-dimethylacetal) = 1:6) gave the N-3 methyl substituted intermediate 3. Dithionite reduction of this product afforded N-methyl derivatives AG-19-K1 and AG-3. AG-19-K1 and AG-3 were inactive vs. calf spleen PNP at a concentration of 75 mmol dm–3. Cytotoxic effects of 9-deazaguanine derivatives on cell growth were determined by the MTT assay. Investigated derivatives showed moderate antiproliferative activity towards examined tumor cells. At a concentration of 10–3 mol dm–3, AG-19-K1 inhibited the growth of JURKAT, K562 and AGS cells by approximately 80 %. At the same concentration, AG-3 and 9-DG inhibited cell proliferation by 40-50 % of all tested lines, except MOLT-4 and HL-60. The PNP gene expression was changed in treated leukemia cells after exposure to AG-19-K1 and 9-DG in a time-dependent manner

Still a Long Way to Fully Understanding the Molecular Mechanism of Escherichia coli Purine Nucleoside Phosphorylase

The results of several decades of studying the catalytic mechanism of Escherichia colt purine nucleoside phosphorylases (PNP) by solution studies and crystal structure determinations are presented. Potentially PNPs can be used for enzyme-activating prodrug gene therapy against solid tumours because of the differences in specificity between human and E. coli PNPs. Biologically active form of PNP from E. coli is a homohexamer that catalyses the phosphorolytic cleavage of the glycosidic bond of purine nucleosides. Two conformations of the active site are possible after substrate(s) binding: open and closed. A series of determined 3D-structures of PNP binary and ternary complexes facilitated the prediction of the main steps in the catalytic mechanism. For their validation the active site mutants: Arg24Ala, Asp204Ala, Arg217Ala, Asp204Asn and double mutant Asp204Ala/Arg217Ala were prepared, The activity tests confirm that catalysis involves protonation of the purine base at position N7 and give better insight into the cooperativity between subunits in this oligomeric enzyme