Influence of coordination modes of 4,4′-bipyridine and secondary bonds on the structural assembles: Syntheses,crystal structures and properties of two lead(II) 3-sulfobenzoate coordination polymers

Two novel structures, {[Pb(3-sb)(4,4′-bipy)_0.5](H₂O)}_n (1) together with the previously reported complex {[Pb(3-sb)(H₂O)₂](4,4′-bipy)}_n (2), where 3-sb is 3-sulfobenzoate dianion and 4,4′-bipy is 4,4′-bipyridine, were synthesized and characterized by IR, elemental analyses, TGA, powder X-ray, fluorescent and single-crystal X-ray analyses. The highly ordered 2-D structure of 2 exists as π–π stacking and hydrogen-bonding interactions, while complex 1 is a 3-D network with 2-D interpenetration layers without π–π and hydrogen-bonding interactions and with abundant secondary bonding interactions. Therefore, complex 1 has thermally more stable structure than that of complex 2, and water molecules can be removed and re-combined in complex 1.     

Comparing the midpoint and endpoint approaches based on ReCiPe—a study of commercial buildings in Hong Kong

Purpose

Life cycle assessment (LCA) has been increasingly implemented in analyzing the environmental performance of buildings and construction projects. To assess the life cycle environmental performance, decision-makers may adopt the two life cycle impact assessment (LCIA) approaches, namely the midpoint and endpoint models. Any imprudent usage of the two approaches may affect the assessment results and thus lead to misleading findings. ReCiPe, a well-known work, includes a package of LCIA methods to provide assessments on both midpoint and endpoint levels. This study compares different potential LCIA results using the midpoint and endpoint approaches of ReCiPe based on the assessment of a commercial building in Hong Kong.

Methods

This paper examines 23 materials accounting for over 99 % of the environmental impacts of all the materials consumed in commercial buildings in Hong Kong. The midpoint and endpoint results are compared at the normalization level. A commercial building in Hong Kong is further studied to provide insights as a real case study. The ranking of impact categories and the contributions from various construction materials are examined for the commercial building. Influence due to the weighting factors is discussed.

Results and discussion

Normalization results of individual impact categories of the midpoint and endpoint approaches are consistent for the selected construction materials. The difference in the two approaches can be detected when several impact categories are considered. The ranking of materials is slightly different under the two approaches. The ranking of impact categories demonstrates completely different features. In the case study of a commercial building in Hong Kong, the contributions from subprocesses are different at the midpoint and endpoint. The weighting factors can determine not only the contributions of the damage categories to the total environment, but also the value of a single score.

Conclusions

In this research, the midpoint and endpoint approaches are compared using ReCiPe. Information is whittled down from the inventories to a single score. Midpoint results are comprehensive while endpoint results are concise. The endpoint approach which provides additional information of damage should be used as a supplementary to the midpoint model. When endpoint results are asked for, a LCIA method like ReCiPe that provides both the midpoint and endpoint analysis is recommended. This study can assist LCA designers to interpret the midpoint and endpoint results, in particular, for the assessment of commercial buildings in Hong Kong.     

A field study on the influence of food and immune priming on a bumblebee–gut parasite system

Laboratory experiments are often preferred over field experiments because they allow the control of confounding factors that would otherwise influence the causal effect of a particular focal experimental factor. These confounding factors can, however, significantly alter the response of an organism confronted with a particular situation, which can have great implications. In a field experiment with a bumblebee host–parasite system, we looked at the influence of additional food supply and immune challenge on various colony fitness values and parasite traits. We could confirm the importance of food on the colony fitness, but not on parasite infection probability or parasite genetic diversity. In contrast to the findings of laboratory experiments of this system, challenge of the immune system had no significant effect on colony fitness or parasite infections. These results likely reflect an overriding effect of environmental variation without disproving the concept of a cost of defence per se. But the results also demonstrate that confounding factors purposely controlled for in the laboratory have to be weighed against their ecological relevance, and stress the need for careful analysis before any direct transfer is made of laboratory results to field situations.     

Measuring the host specificity of plant-feeding mites based on field data — a case study of the <Emphasis Type=Italic>Aceria</Emphasis> species

For the majority of eriophyoid species, host ranges have been established purely on the basis of collection records, usually without quantitative data. The aim of this study was to: (1) quantitatively examine published literature to explore whether relevant analyses of field-collected quantitative data were used to assess host specificity of herbivores; (2) propose a protocol for data analysis that could be applied to plant-feeding mites; (3) analyse host specificity of the grass-feeding Aceria species as a case study. Field data were collected in Central and Northern Europe over a period of 11 years, and included 73 grass species. For the eight Aceria species found, infestation parameters and host specificity indexes were assessed. Accumulation curves were calculated to study how the sampling effort influenced estimates of host specificity indexes. A literature analysis showed that among the studies that declared an aim of estimating the host range only 56% of them applied any quantitative analysis or informed on estimation reliability. The analysis of field-collected data and its interpretation showed the most complete and reliable conclusions about the host specificity of Aceria species when all indices were considered and, if available, other information about the mite’s ecology and biology. It was shown that estimates of host specificity could be strongly affected by sampling effort, and that several hundreds of samples should be collected for measuring the host specificity of grass-infesting mites, at least. Recommendations regarding host specificity estimation on the basis of field data are given.     

Lack of an association between -308G>A polymorphism of the TNF-α gene and liver cirrhosis risk based on a meta-analysis

TNF-α is a potential proinflammatory cytokine that plays an important role in the pathogenesis of liver cirrhosis. We investigated a possible association between TNF-α -308G>A polymorphism and liver cirrhosis risk by conducting a meta-analysis. Publications addressing the association between TNF-α -308G>A and liver cirrhosis risk were selected from the Pubmed and Embase databases. Data were extracted from the studies by two independent reviewers; odds ratio (OR) with a 95% confidence interval (CI) was calculated from these data. The meta-analysis was performed by Review Manager Version 5.0.24 and STATA Version 9.2. Eleven studies were retrieved, reporting a total of 1796 liver cirrhosis cases and 2113 healthy controls. A meta-analysis of these 11 studies identified no significant association between TNF-α -308G>A polymorphism and liver cirrhosis risk in all comparisons of G vs A allele; GG vs GA + AA; GG + GA vs AA; GG vs AA; GG vs GA (OR = 1.14, 95%CI = 0.85-1.55, P = 0.38; OR = 1.24, 95%CI = 0.87- 1.77, P = 0.24; OR = 0.90, 95%CI = 0.62-1.30, P = 0.57; OR = 1.03, 95%CI = 0.56-1.89, P = 0.92; OR = 1.30, 95%CI = 0.90-1.88, P = 0.17; respectively). In conclusion, we found no association between TNF-α -308G>A polymorphism and liver cirrhosis risk, both in Caucasian and Asian populations.     

Effects of a thiolate axial ligand on the π→π* electronic states of oxoferryl porphyrins: a study of the optical and resonance Raman spectra of compounds I and II of chloroperoxidase

Optical absorption and resonance Raman spectra have been investigated for enzymatic intermediates, compounds I and II, of chloroperoxidase (CPO) which contains a thiolate-ligated iron porphyrin. Compound I of CPO (CPO-I), an oxoferryl porphyrin pi cation radical, gave an apparently asymmetric single-peaked Soret band at 367 nm, for which band fitting analyses revealed the presence of two transition bands around 365 and 415 nm. Compound II of CPO (CPO-II), an oxoferryl neutral porphyrin, gave a split Soret spectrum with two bands (blue and red Soret bands) at 373 and 436 nm. Thus both CPO-I and CPO-II can be categorized as hyperporphyrins. The maximum extinction coefficients (epsilon(b) and epsilon(r)) and energies (Eb and Er) of the blue and red Soret bands of CPO-II were found to fall on an epsilon(b)/epsilon(r) versus Eb-Er correlation line derived from data reported for six-coordinate ferrous derivatives of cytochrome P450 and CPO. Corresponding data for CPO-I did not fall on the correlation line. Resonance enhancement of the FeIV=O stretching (vFeO) Raman band was found for CPO-I when Raman scattering was excited at wavelengths within both transition bands around 365 and 415 nm, while the vFeO Raman band was not identified for CPO-II at any of the excitation wavelengths examined here. These findings suggest that the thiolate axial ligand causes Soret band splitting of CPO-II through configuration interaction between the sulfur-->porphyrin e(g)* charge transfer and porphyrin a1u,a2u-->e(g)* transitions, while the FeO portion is important in determining the shape of the Soret band of CPO-I.     

The diversification of the northern temperate woody flora – A case study of the Elm family (Ulmaceae) based on phylogenomic and paleobotanical evidence

Ulmaceae is a woody family widespread in northern temperate forests. Despite the ecological importance of this family, its phylogeny and biogeographic history are poorly understood. In this study, we reconstruct phylogenetic relationships within the family and infer spatio-temporal diversification patterns based on chloroplast genome (complete cpDNA) and nuclear ribosomal DNA sequences (nrDNA). The seven Ulmaceae genera are resolved in two main clades (temperate vs. tropical) by both cpDNA and nrDNA sequences. The temperate clade includes four genera, Hemiptelea, Zelkova, Planera, and Ulmus. The relationships among Planera and other genera are controversial because of inconsistent topologies between plastid and nuclear data. The tropical clade includes three genera ((Ampelocera, Phyllostylon), Holoptelea). Molecular dating and diversification analyses show that Ulmaceae originated in the Early Cretaceous (ca. 110–125 Ma) with the main lineages establishing from the Late Cretaceous to the early Eocene. The diversification rate slowed during the middle to the late Paleogene (ca. 23–45 Ma), followed by a rapid diversification of the East Asian temperate group in the Neogene, congruent with a global cooling event. The ancestral state optimization analysis suggests an East Asian origin of the temperate Ulmaceae clade during the Paleocene, which is consistent with the fossil record. Both phylogenomic and fossil evidence support East Asia as a center of origin and diversification for the temperate woody lineages.     

Review of the genotoxicity and carcinogenicity of antischistosomal drugs; is there a case for a study of mutation epidemiology? Report of a task group on mutagenic antischistosomals

One of the interests of ICPEMC is to identify situations in which the possible induction of inherited defects in man by mutagen exposure could actually be studied. The large-scale use of mutagenic drugs in field programmes against schistosomiasis, mainly during the 1970's, was considered a possible case. An ICPEMC task group approached the problem by (1) updating the genetic toxicology data base for antischistosomal drugs, and (2) reviewing possible study areas. Expertise was combined from genetic toxicology, mutation epidemiology and tropical medicine.It was considered that: (a) if any, hycanthone would be the most appropriate candidate drug for study; (b) it would be virtually impossible to meet the basic requirements of an appropriate mutation epidemiology study, in endemic countries; (c) as more defined genetic endpoints would be selected (e.g. sentinel phenotypes) the required large sample sizes would seem prohibitive, since documentation on past programmes is limited and local demography would render the reliable tracking of substantial numbers of offspring of treated persons an almost impossible task; (d) in most endemic countries proper diagnosis and registration of inherited defects is largely lacking; (e) the problems encountered in demonstrating inherited effects in humans after heavy or chronic exposure to established animal mutagens such as ionizing radiation and cancer chemotherapy, in combination with the ambiguous nature of the animal germ cell data with hycanthone, do not particularly warrant large expectations; (f) since non-mutagenic antischistosomal drugs are now in use, the problem is academic and of low priority in the endemic countries whose medical and research resources are often limited. Thus, studying offspring of hycanthone-treated people to demonstrate the mutagenic potential of the drug in man is not a viable enterprise. (See, however, note added in proof, p. 75.)     

Structure, spectroscopic and magnetic properties of a novel 1-D coordination copper(II) polymer containing BIMAM ligand [BIMAM = bis(imidazol-2-yl)methylaminomethane] and μ-1,3 squarato bridges

This paper reports the synthesis and complete characterization (structural, spectroscopic and magnetic) of [Cu(HBIMAM)Cl(C₄O₄)]_n · (H₂O)_n [BIMAM = bis(imidazol-2-yl)methylaminomethane]. This compound is made of infinite chains - running along c axis - built from [CuCl(HBIMAM)]⁺ units bridged together by μ-O¹,O³-bis(monodentate) squarate anions. Non-covalent interactions (H-bonds and π-π) drive the build-up of an infinite three-dimensional array. The coordination polyhedron about the copper(II) ion is distorted square pyramidal. The EPR spectrum is indicative of a d_z²-y² ground state for the Cu(II) ions with significant contribution of d_z². Magnetic susceptibility measurements in the range 1.8-200 K show weak antiferromagnetic exchange interactions (2J = −3.5(1) cm⁻¹). The observed magnetic behaviour is discussed in terms of the crystal structure and compared with that observed in related copper(II) complexes containing μ-O¹,O³-squarato bridges.     

Effects of estradiol-17β on cholesterol metabolism in the rat: A study using a deuterium label and mass spectrometry

The effect of estradiol-17β (E₂) on several important aspects of cholesterol metabolism were examined in the rat. Ovariectomized rats were implanted subcutaneously with 1 or 4 cm. of silastic tubing packed with E2, and were also given 2% D₂O in their drinking water. The E2 diffused slowly out of the implants and the two different lengths of tubing resulted in constant E2 blood concentrations of either high (4.0 cm) or physiological (1.0 cm) levels. By measuring the rate of incorporation of deuterium into plasma cholesterol by mass spectrometry over a period of 42 days, we determined the rate constant of cholesterol synthesis and cholesterol turnover time and rate under two E2 dosage conditions. E2 treatment did not affect the rate constant of cholesterol synthesis or the cholesterol turn-over time. However, cholesterol turnover rate (mg synthesized/day) showed a dose dependent reduction with increasing doses of E2. This may be secondarily caused by E2's suppression of both food Intake and subsequent weight gain; E2 treated animals are smaller and, therefore, synthesize less cholesterol per day. Additionally, E2 treated animals showed a rise in plasma cholesterol levels and in the fraction of labeled cholesterol appearing in the plasma.     

Specific cation effect on quenching reactions of excited tris(α,α′-diimine) ruthenium(II) and chromium(III) complexes by cyanide complexes in aqueous solutions

Specific salt effects were studied on the quenching reaction of excited [Ru(NN)₃]²⁺ (NN=2,2′-bipyridine(bpy), 1,10-phenanthrorine(phen)) and [Cr(bpy)₃]³⁺ by [Cr(CN)₆]³⁻, [Fe(CN)₆]³⁻ and [Ni(CN)₄]²⁻ in aqueous solutions as a function of alkali metal ions which were added for adjustment of ionic strength. The quenching rate constants in [Ru(NN)₃]²⁺-[Cr(CN)₆]³⁻ and [Cr(bpy)₃]³⁺-[Cr(CN)₆]³⁻ systems are changed by the cations as Li⁺>Na⁺>K⁺≈Rb⁺≈Cs⁺. On the other hand, the rate constants in [Ru(NN)₃]²⁺-[Fe(CN)₆]³⁻ and [Ru(NN)₃]²⁺-[Ni(CN)₄]²⁻ systems, which are diffusion-controlled reactions, are not varied by the alkali metal cations. The obtained order (Li⁺>Na⁺>K⁺≈Rb⁺≈Cs⁺) of the quenching rate constant is quite different from salt effects, Li⁺<Na⁺<K⁺<Rb⁺<Cs⁺, which have been obtained in the electron transfer reactions between complex anions.     

Design,synthesis and preliminary structure–activity relationship investigation of nitrogen-containing chalcone derivatives as acetylcholinesterase and butyrylcholinesterase inhibitors: a further study based on Flavokawain B Mannich base derivatives

In order to study the structure–activity relationship of Flavokawain B Mannich-based derivatives as acetylcholinesterase (AChE) inhibitors in our recent investigation, 20 new nitrogen-containing chalcone derivatives (4?a–8d) were designed, synthesized, and evaluated for AChE inhibitory activity in vitro. The results suggested that amino alkyl side chain of chalcone dramatically influenced the inhibitory activity against AChE. Among them, compound 6c revealed the strongest AChE inhibitory activity (IC₅₀ value: 0.85?μmol/L) and the highest selectivity against AChE over BuChE (ratio: 35.79). Enzyme kinetic study showed that the inhibition mechanism of compound 6c against AChE was a mixed-type inhibition. The molecular docking assay showed that this compound can both bind with the catalytic site and the peripheral site of AChE.     

Identification of the tautomeric form of formycin A in its complex with<Emphasis Type="Italic"> Escherichia coli</Emphasis> purine nucleoside phosphorylase based on the effect of enzyme–ligand binding on fluorescence and phosphorescence

Fluorescence and phosphorescence emission spectroscopy were employed to study the interaction of Escherichia coli purine nucleoside phosphorylase (PNP) with its specific inhibitor, formycin A (FA), a close structural analogue of adenosine (natural substrate), in the absence and presence of phosphate (P_i, substrate). Formation of enzyme–FA complexes led to marked quenching of enzyme tyrosine intrinsic fluorescence and phosphorescence, with concomitant increases in fluorescence and phosphorescence of FA. Fluorescence resonance energy transfer from the protein Tyr160 residue to the FA base moiety was identified as a major mechanism of protein fluorescence quenching, increased by addition of P_i. The effects of enzyme–FA interactions on the nucleoside excitation and emission spectra for fluorescence and phosphorescence revealed shifts in the tautomeric equilibrium of the bound FA, i.e. from the N(1)–H tautomer (predominant in solution) to the N(2)–H form, enhanced by the presence of P_i. The latter was confirmed by enzyme–ligand dissociation constant (K _d) values of 5.9±0.4 and 2.1±0.3 M in the absence and presence of P_i, respectively. Addition of glycerol (80%, v/v) led to a lower enzyme affinity (K _d70 M), without changes in binding stoichiometry. Enzyme–FA complex formation led to a higher increase of the fluorescence than the phosphorescence band of the ligand, consistent with the fact that the N(2)–H tautomer is characterized by a weaker phosphorescence than the N(1)–H tautomeric form. These results show, for the first time, the application of phosphorescence spectroscopy to the identification of the tautomeric form of the inhibitor bound by the enzyme.Abbreviations Ado adenosine - FA formycin A [3-(-d-ribofuranosyl)-7-aminopyrazolo[4,3-d]pyrimidine] - FB formycin B - FRET fluorescence resonance energy transfer - Guo guanosine - Hepes N-(2-hydroxyethyl)piperazine-N-(2-ethanesulfonic acid) - Ino inosine - m¹FA N(1)-methylformycin A - m²FA N(2)-methylformycin A - m⁴FA N(4)-methylformycin A - m⁶FA N(6)-methylformycin A - m⁷Guo N(7)-methylguanosine - P_i orthophosphate - PNP purine nucleoside phosphorylase - Xao xanthosine     

Poro-elastic modeling of Syringomyelia – a systematic study of the effects of pia mater,central canal,median fissure,white and gray matter on pressure wave propagation and fluid movement within the cervical spinal cord

Syringomyelia, fluid-filled cavities within the spinal cord, occurs frequently in association with a Chiari I malformation and produces some of its most severe neurological symptoms. The exact mechanism causing syringomyelia remains unknown. Since syringomyelia occurs frequently in association with obstructed cerebrospinal fluid (CSF) flow, it has been hypothesized that syrinx formation is mechanically driven. In this study we model the spinal cord tissue either as a poro-elastic medium or as a solid linear elastic medium, and simulate the propagation of pressure waves through an anatomically plausible 3D geometry, with boundary conditions based on in vivo CSF pressure measurements. Then various anatomic and tissue properties are modified, resulting in a total of 11 variations of the model that are compared. The results show that an open segment of the central canal and a stiff pia (relative to the cord) both increase the radial pressure gradients and enhance interstitial fluid flow in the central canal. The anterior median fissure, anisotropic permeability of the white matter, and Poisson ratio play minor roles.     

A reappraisal of the Pleurotus eryngii complex – New species and taxonomic combinations based on the application of a polyphasic approach,and an identification key to Pleurotus taxa associated with Apiaceae plants

The Pleurotus eryngii species-complex comprises choice edible mushrooms growing on roots and lower stem residues of Apiaceae (umbellifers) plants. Material deriving from extensive sampling was studied by mating compatibility, morphological and ecological criteria, and through analysis of ITS1-5.8S-ITS2 and IGS1 rRNA sequences. Results revealed that P. eryngii sensu stricto forms a diverse and widely distributed aggregate composed of varieties elaeoselini, eryngii, ferulae, thapsiae, and tingitanus. Pleurotuseryngii subsp. tuoliensis comb. nov. is a phylogenetically sister group to the former growing only on various Ferula species in Asia. The existence of Pleurotusnebrodensis outside of Sicily (i.e., in Greece) is reported for the first time on the basis of molecular data, while P. nebrodensis subsp. fossulatus comb. nov. is a related Asiatic taxon associated with the same plant (Prangos ferulacea). Last, Pleurotusferulaginis sp. nov. grows on Ferulago campestris in northeast Italy, Slovenia and Hungary; it occupies a distinct phylogenetic position accompanied with significant differences in spore size and mating incompatibility versus other Pleurotus populations. Coevolution with umbellifers and host/substrate specificity seem to play key roles in speciation processes within this fungal group. An identification key to the nine Pleurotus taxa growing in association with Apiaceae plants is provided.     

Larvicidal activity of spinosad and its impact on oviposition preferences of the West Nile vector Culex pipiens biotype molestus – A comparison with a chitin synthesis inhibitor

In the present study, the larvicidal activity of ageing aqueous suspensions of spinosad against larvae of Culex pipiens biotype molestus, as well as their effect on the oviposition preferences of adult gravid females were evaluated in laboratory bioassays. Spinosad was applied at its label dose and the aqueous stock suspensions were stored for various ageing intervals up to 38 days. Untreated distilled water and diflubenzuron served as negative and positive control, respectively. Stock suspensions were taken after 0, 2, 6, 8, 16, 30 and 38 days of storage for diflubenzuron and after 0, 2, 6, 8, 20 and 27 days for spinosad, and were used for the bioassays. Furthermore, the effect of spinosad on the oviposition response of Cx. p. biotype molestus gravid females was investigated in two-choice oviposition preference bioassays. Spinosad was evaluated at half of its label dose and at its label dose, whereas diflubenzuron and distilled water served as positive and negative control, respectively. Results showed that both insecticides were found highly effective for the control of Cx. p. biotype molestus larvae, for ageing intervals up to 27 and 38 days for spinosad and diflubenzuron, respectively. Spinosad acted immediately after the preparation of the insecticidal solution (LT₅₀ = 1.5 h), whereas for aged samples, LT₅₀ values increased with the increase of the ageing interval (LT₅₀ = 5 days for the 27 days old sample). For diflubenzuron, ageing time increased its insecticidal activity, as for aged diflubenzuron-treated solutions, lower LT₅₀ values were achieved. In the oviposition preference bioassays, significantly fewer egg rafts were laid in water treated with spinosad at its label dose compared to control. However, this was not the case for water treated with spinosad at half of its label dose. Oviposition Activity Index (OAI) values were always comprised between −0.3 and 0.3, showing no relevant oviposition deterrence or attraction. The results of the present study contribute to our understanding of the effect of ageing on insecticidal solutions widely used in urban areas to control Cx. p. biotype molestus. Although an important vector of high public health importance, Cx. p. biotype molestus has been scarcely studied as target of environmentally and toxicologically reduced risk insecticides, such as spinosad.