Decompositions of categories over posets and cohomology of categories

Let ? be a small category. We present some results which describe cohomology groups and homotopy colimits of functors defined over ? using cohomology groups and homotopy colimits over certain categories associated to functors from ? to posets. Received: 3 May 1999     

Komplexchemie P‐reicher Phosphane und Silylphosphane. XXV. Bildung und Struktur des [{cyclo‐P3(PtBu2)3}{Ni(CO)2}{Ni(CO)3}]

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XXV. Formation and Structure of [{ cyclo ‐P₃(P^tBu₂)₃}{Ni(CO)₂}{Ni(CO)₃}] ^tBu₂P–P=P(R)^tBu₂ (R = Br, Me) reacts with [Ni(CO)₄] yielding [{cyclo‐P₃(P^tBu₂)₃}{Ni(CO)₂}{Ni(CO)₃}]. The two cis‐^tBu₂P substituents of the cyclotriphosphane, which results from the trimerization of the phosphinophosphinidene ^tBu₂P–P, are coordinating to a Ni(CO)₂ unit forming a five‐membered P₄Ni chelate ring. The trans‐^tBu₂P group is linked to a Ni(CO)₃ unit. The compound crystallizes in the orthorhombic space group Pbca (No. 61) with a = 933.30(5), b = 2353.2(1) and c = 3474.7(3) pm.     

Reaktionen von tBu2P–P=P(Me)tBu2 mit (Et3P)2NiCl2 und [{η2‐C2H4}Ni(PEt3)2]

Coordination Chemistry of P‐rich Phosphanes and Silylphosphanes. XXIII. Reactions of ^tBu₂P–P=P(Me)^tBu₂ with (Et₃P)₂NiCl₂ and [{η²‐C₂H₄}Ni(PEt₃)₂] ^tBu₂P–P=P(Me)^tBu₂ ( 1 ) forms with (Et₃P)₂NiCl₂ ( 2 ) and Na(Nph) the [μ‐(1,3 : 2,3‐η‐^tBu₂P₄^tBu₂){Ni(PEt₃)Cl}₂] ( 3 ) as main product. Using Na/Hg instead as reducing agent the Ni⁰ compounds [{η²‐^tBu₂P–P}Ni(PEt₃)₂] ( 4 ), [{η²‐^tBu₂P–P=P–P^tBu₂}Ni(PEt₃)₂] ( 5 ) and [(Et₃P)Ni(μ‐P^tBu₂)]₂ ( 6 ) with four‐membered Ni₂P₂ ring result. [{η²‐C₂H₄}Ni(PEt₃)₂] yields with 1 also 4 . The compounds were characterized by ¹H and ³¹P{¹H} NMR investigations and 3 also by a single crystal X‐ray analysis. It crystallizes triclinic in the space group P 1 with a = 1129.4(2), b = 1256.8(3), c = 1569.5(3) pm, α = 72.44(3)°, β = 70.52(3)° and γ = 74.20(3)°.     

Polish Varieties of Industrial Hemp and Their Utilisation in the Efficient Production of Lignocellulosic Ethanol

Nowadays, more and more attention is paid to the development and the intensification of the use of renewable energy sources. Hemp might be an alternative plant for bioenergy production. In this paper, four varieties of Polish industrial hemp (Białobrzeskie, Tygra, Henola, and Rajan) were investigated in order to determine which of them are the most advantageous raw materials for the effective production of bioethanol. At the beginning, physical and chemical pretreatment of hemp biomass was carried out. It was found that the most effective is the alkaline treatment with 2% NaOH, and the biomasses of the two varieties were selected for next stages of research: Tygra and Rajan. Hemp biomass before and after pretreatment was analyzed by FTIR and SEM, which confirmed the effectiveness of the pretreatment. Next, an enzymatic hydrolysis process was carried out on the previously selected parameters using the response surface methodology. Subsequently, the two approaches were analyzed: separated hydrolysis and fermentation (SHF) and a simultaneous saccharification and fermentation (SSF) process. For Tygra biomass in the SHF process, the ethanol concentration was 10.5 g∙L⁻¹ (3.04 m³·ha⁻¹), and for Rajan biomass at the SSF process, the ethanol concentration was 7.5 g∙L⁻¹ (2.23 m³·ha⁻¹). In conclusion, the biomass of Polish varieties of hemp, i.e., Tygra and Rajan, was found to be an interesting and promising raw material for bioethanol production.     

Bioactive Properties of a Novel Antibacterial Dye Obtained from Laccase-Mediated Oxidation of 8-Anilino-1-naphthalenesulfonic Acid

Fungal laccase obtained from a Cerrena unicolor strain was used as an effective biocatalyst for the transformation of 8-anilino-1-naphthalenesulfonic acid into a green-coloured antibacterial compound, which can be considered as both an antimicrobial agent and a textile dye, simultaneously. The process of biosynthesis was performed in buffered solutions containing methanol as a co-solvent, allowing better solubilisation of substrate. The transformation process was optimised in terms of the buffer pH value, laccase activity, and concentrations of the substrate and co-solvent. The crude product obtained exhibited low cytotoxicity, antibacterial properties against Staphylococcus aureus and Staphylococcus epidermidis, and antioxidant properties. Moreover, the synthesised green-coloured compound proved non-allergenic and demonstrated a high efficiency of dyeing wool fibres.     

Zebrafish—An Optimal Model in Experimental Oncology

A thorough understanding of cancer pathogenesis is a necessary step in the development of more effective and safer therapy. However, due to the complexity of the process and intricate interactions, studying tumor development is an extremely difficult and challenging task. In bringing this issue closer, different scientific models with various advancement levels are helpful. Cell cultures is a system that is too simple and does not allow for multidirectional research. On the other hand, rodent models, although commonly used, are burdened with several limitations. For this reason, new model organisms that will allow for the studying of carcinogenesis stages and factors reliably involved in them are urgently sought after. Danio rerio, an inconspicuous fish endowed with unique features, is gaining in importance in the world of scientific research. Including it in oncological research brings solutions to many challenges afflicting modern medicine. This article aims to illustrate the usefulness of Danio rerio as a model organism which turns out to be a powerful and unique tool for studying the stages of carcinogenesis and solving the hitherto incomprehensible processes that lead to the development of the disease.     

Synthesis and Structural Study of Amidrazone Derived Pyrrole-2,5-Dione Derivatives: Potential Anti-Inflammatory Agents

1H-pyrrole-2,5-dione derivatives are known for their wide range of pharmacological properties, including anti-inflammatory and antimicrobial activities. This study aimed to synthesize new 3,4-dimethyl-1H-pyrrole-2,5-dione derivatives 2a–2f in the reaction of N³-substituted amidrazones with 2,3-dimethylmaleic anhydride and evaluate their structural and biological properties. Compounds 2a–2f were studied by the ¹H-¹³C NMR two-dimensional techniques (HMQC, HMBC) and single-crystal X-ray diffraction (derivatives 2a and 2d). The anti-inflammatory activity of compounds 2a–2f was examined by both an anti-proliferative study and a production study on the inhibition of pro-inflammatory cytokines (IL-6 and TNF-α) in anti-CD3 antibody- or lipopolysaccharide-stimulated human peripheral blood mononuclear cell (PBMC) cultures. The antibacterial activity of compounds 2a–2f against Staphylococcus aureus, Enterococcus faecalis, Micrococcus luteus, Esherichia coli, Pseudomonas aeruginosa, Yersinia enterocolitica, Mycobacterium smegmatis and Nocardia corralina strains was determined using the broth microdilution method. Structural studies of 2a–2f revealed the presence of distinct Z and E stereoisomers in the solid state and the solution. All compounds significantly inhibited the proliferation of PBMCs in anti-CD3-stimulated cultures. The strongest effect was observed for derivatives 2a–2d. The strongest inhibition of pro-inflammatory cytokine production was observed for the most promising anti-inflammatory compound 2a.     

Anti-Tumor Active Isopropylated Fused Azaisocytosine-Containing Congeners Are Safe for Developing Danio rerio as Well as Red Blood Cells and Activate Apoptotic Caspases in Human Breast Carcinoma Cells

New isopropylated fused azaisocytosine-containing congeners (I–VI) have previously been reported as promising anticancer drug candidates, so further research on these molecules in the preclinical development phase is fully justified and necessary. For this reason, in the present paper, we assess the toxicity/safety profiles of all the compounds using Danio rerio and red blood cell models, and examine the effect of the most selective congeners on the activation of apoptotic caspases in cancer and normal cells. In order to evaluate the effect of each molecule on the development of zebrafish embryos/larvae and to select the safest compounds for further study, various phenotypic parameters (i.e., mortality, hatchability, heart rate, heart oedema, yolk sac utilization, swim bladder development and body shape) were observed, and the half maximal lethal concentration, the maximal non-lethal concentration and no observed adverse effect concentration for each compound were established. The effect of all the isopropylated molecules was compared to that of an anticancer agent pemetrexed. The lipophilicity-dependent structure–toxicity correlations were also determined. To establish the possible interaction of the compounds with red blood cells, an ex vivo hemolysis test was performed. It was shown that almost all of the investigated isopropylated congeners have no adverse phenotypic effect on zebrafish development during five-day exposure at concentrations up to 50 μM (I–III) or up to 20 μM (IV–V), and that they are less toxic for embryos/larvae than pemetrexed, demonstrating their safety. At the same time, all the molecules did not adversely affect the red blood cells, which confirms their very good hemocompatibility. Moreover, they proved to be activators of apoptotic caspases, as they increased caspase-3, -7 and -9 levels in human breast carcinoma cells. The conducted research allows us to select—from among the anticancer active drug candidates—compounds that are safe for developing zebrafish and red blood cells, suitable for further in vivo pharmacological tests.     

Growth morphology of crystals from kinetic and geometric perspective

The growth morphology of crystals is analysed from macroscopic point of view and the recent developments in this field are surveyed. In particular, it is shown that, for specific geometry characterized by interfacial angles a given face can increase in size for a very wide range of relative growth rates and need not be the slow‐growing face. Even growing faster than the neighbouring faces, such a face can increase in its size. However, there are other faces with other specific geometry, which can decrease the size growing more slowly than one of the neighbouring faces. If the growth time is sufficiently long, such a face may disappear and not be represented in the final crystal morphology. In the present survey the concepts given earlier [5] are extended. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Solubility of Solid 1-Hexene and 2-Methylpentane in Liquid Argon and Nitrogen at the Standard Boiling Points of the Solvents

The solubilities of solid 1-hexene and 2-methylpentane in liquid argon at a temperature of 87.3 K and in liquid nitrogen at 77.4 K have been measured by the filtration method. The hydrocarbon contents in solutions were determined using gas chromatography. The experimental value of the mole fraction solubility of solid 1-hexene in liquid argon at 87.3 K is (3.87 ± 0.74) × 10^-7 and (7.94 ± 2.47) × 10^-9 in liquid nitrogen at 77.4 K. The experimental value of the mole fraction solubility of solid 2-methylpentane in liquid argon at 87.3 K is (1.45 ± 0.36) × 10^-5 and (6.80 ± 2.16) × 10^-8 in liquid nitrogen at 77.4 K. The Preston–Prausnitz method was used for calculation of the solubilities of solid hydrocarbons in liquid argon in the temperature range 84.0–110.0 K and in liquid nitrogen from 64.0 to 90.0 K. The solvent–solute interaction parameters 1₁₂ were also calculated. At 90.0 K, liquid argon is a better solvent for solid 1-hexene and 2-methylpentane than is liquid nitrogen.