A new test for cleaning efficiency assessment of cleaners for hard surfaces

A new test was developed to assess the efficiency of no-wiping hard-surface cleaning. The test allows cleaner comparisons according to their ability to remove greasy soils. The chosen approach minimizes the mechanical forces applied while cleaning so that the interactions between a detergent solution and the soil to be removed can be characterized. For this, immersion cleaning was chosen, with coated stainless steel as substrate and pigmented oils as the model soil. Several parameters were studied in defined ranges using the Experimental Design method and systematic comparisons. The test shows high reliability on degreasing assessments and is there-fore especially suited to optimization of nonionic surfactant mixes. The originality of the test lies in the possibility of keeping a visual trace of the cleaned substrate appearance by imprinting it on a piece of paper. The validation of the test leads to corroboration of several practical observations. Temperature and agitation play a major role in cleaning efficiency. Detergent solution concentration is a more relevant parameter than pH. Sodium carbonate is shown to have a higher buffering effect than pentahydrated sodium metasilicate. The test is easy to set up, highly sensitive, and can be adapted to solve the problems encountered by formulators of detergent cleaners, such as screening the best ethoxylated fatty alcohol mix for better degreasing properties.     

Promising Stability of Gold-Based Catalysts Prepared by Direct Anionic Exchange for DeNO x Applications in Lean Burn Conditions

Supported gold catalysts on γ-Al₂O₃ have been investigated in the catalytic reduction of NO _x in simulated Diesel exhaust gas conditions. Different parameters have been examined essentially the mode of gold incorporation via classical deposition–precipitation and anionic exchange methods and the nature of the pre-activation thermal treatment. The resistance to thermal ageing under reactive conditions at 500 °C was found completely different with a significant rate enhancement on anionic-exchange samples. Further comparisons also show that the nature of the pre-activation thermal treatment influences the extent of surface reconstructions during thermal ageing with a detrimental effect of reductive pre-treatment on the catalytic performances.     

A new class of pyrrolidin-2-ones: synthesis and pharmacological study. II

OBJECTIVE: The measurements of transient evoked otoacoustic emissions and distortion-product otoacoustic emissions are being used increasingly, both as an objective hearing test clinically, and as a research tool to investigate the micromechanical aspects of cochlear function. We hypothesized that localized damage in the apical or middle cochlear turns may have an influence on the micromechanics and the function of adjacent, apparently normal cochlea. For that purpose, we used an animal model of localized apical and middle-turn cochlear lesions. METHOD: Extent of damage was assessed by scanning electron microscopy and the function of the damaged cochlea by change in the otoacoustic emission (OAE) levels. RESULTS: We found that localized damage to the apical or middle turn may be accompanied by an increase in OAE measured from adjacent apparently normal cochlea. CONCLUSION: Explanations to this phenomenon are suggested, and possible clinical associations such as to Meniere's disease and to sudden hearing loss are reviewed.     

Hydrogen bonding of amino acid side chains to nucleic acid bases

Absorption studies of hydrogen bonding association between nucleic acid bases and amino acid side chains show that association constants can be determined from difference absorption spectra in cyclohexane and chloroform. Association constants for the binding of 9-ethyladenine, 1-cyclohexyluracil and 1-cyclohexylcytosine to side chains of serine, threonine, aspartic acid, lysine, cystéine, methionine and tyrosine are reported. Results obtained in chloroform and cyclohexane are compared.     

Synthesis, Crystal Structure and Interaction With DNA of N,N'-(Butane-1,4-Diyl)Bis(Guanidinium) Tetrachloroplatinate (II)

The design, synthesis, crystal structure and interaction with DNA of the N,N'-(butane-1,4-diyl)bis(guanidinium) tetrachloroplatinate(ll) are described. Crystal data: a = 8.152(1), b = 8.889(4), c = 10.700(3) A , alpha = 81.59(3), beta = 87.99(5), gamma = 78.48(6) degrees , V = 752(1) A(3), Z = 2 , space group P-1. The structure was refined to R = 0.039 and Rw = 0.046 from 1853 reflections (I > 3sigma(I)). This compound, named PtC(4)Gua, does not exhibit a center of symmetry and the center linker chain C(2) - C(3) - C(4) - C(5) is in gauche conformation. The cation is bisprotonated with the H(+) attached to the imine group of each terminal guanidinium function. The presence of the platinum moiety reinforces the binding of the butane(bis)guanidinium structure with double stranded DNA as judged from thermal denaturation studies and DNA unwinding experiments.     

Front Cover: Structure-Based Design,Synthesis, and Biological Evaluation of Triazole-Based smHDAC8 Inhibitors (ChemMedChem 7/2020)

Schistosomiasis is a neglected tropical disease caused by parasitic flatworms of the genus Schistosoma, which affects over 200 million people worldwide and leads to at least 300,000 deaths every year. In this study, initial screening revealed the triazole-based hydroxamate 2 b (N-hydroxy-1-phenyl-1H-1,2,3-triazole-4-carboxamide) exhibiting potent inhibitory activity toward the novel antiparasitic target Schistosoma mansoni histone deacetylase 8 (smHDAC8) and promising selectivity over the major human HDACs. Subsequent crystallographic studies of the 2 b /smHDAC8 complex revealed key interactions between the inhibitor and the enzyme's active site, thus explaining the unique selectivity profile of the inhibitor. Further chemical modifications of 2 b led to the discovery of 4-fluorophenoxy derivative 21 (1-[5-chloro-2-(4-fluorophenoxy)phenyl]-N-hydroxy-1H-1,2,3-triazole-4-carboxamide), a nanomolar smHDAC8 inhibitor (IC₅₀=0.5 μM), exceeding the smHDAC8 inhibitory activity of 2 b and SAHA (vorinostat), while exhibiting an improved selectivity profile over the investigated human HDACs. Collectively, this study reveals specific interactions between smHDAC8 and the synthesized triazole-based inhibitors and demonstrates that these small molecules represent promising lead structures, which could be further developed in the search for novel drugs for the treatment of schistosomiasis.     

Cost assessment and ecological effectiveness of nutrient reduction options for mitigating Phaeocystis colony blooms in the Southern North Sea: an integrated modeling approach

Nutrient reduction measures have been already taken by wealthier countries to decrease nutrient loads to coastal waters, in most cases however, prior to having properly assessed their ecological effectiveness and their economic costs. In this paper we describe an original integrated impact assessment methodology to estimate the direct cost and the ecological performance of realistic nutrient reduction options to be applied in the Southern North Sea watershed to decrease eutrophication, visible as Phaeocystis blooms and foam deposits on the beaches. The mathematical tool couples the idealized biogeochemical GIS-based model of the river system (SENEQUE-RIVERSTRAHLER) implemented in the Eastern Channel/Southern North Sea watershed to the biogeochemical MIRO model describing Phaeocystis blooms in the marine domain. Model simulations explore how nutrient reduction options regarding diffuse and/or point sources in the watershed would affect the Phaeocystis colony spreading in the coastal area. The reference and prospective simulations are performed for the year 2000 characterized by mean meteorological conditions, and nutrient reduction scenarios include and compare upgrading of wastewater treatment plants and changes in agricultural practices including an idealized shift towards organic farming. A direct cost assessment is performed for each realistic nutrient reduction scenario. Further the reduction obtained for Phaeocystis blooms is assessed by comparison with ecological indicators (bloom magnitude and duration) and the cost for reducing foam events on the beaches is estimated. Uncertainty brought by the added effect of meteorological conditions (rainfall) on coastal eutrophication is discussed. It is concluded that the reduction obtained by implementing realistic environmental measures on the short-term is costly and insufficient to restore well-balanced nutrient conditions in the coastal area while the replacement of conventional agriculture by organic farming might be an option to consider in the nearby future.     

Distribution of gadomelitol in a human breast tumor model in mice

The study evaluates the tumor distribution of the rapid clearance blood pool agent (RCBPA) gadomelitol, in a breast tumor model. Different techniques were used : (1) tissue gadolinium concentrations measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES), (2) whole body quantitative autoradiography using radiolabeled [¹⁵³Gd] gadomelitol and (3) dynamic contrast-enhanced MRI with compartmental analysis. An accumulation of gadomelitol in tumors compared to muscle was observed 30 min and 3 h post injection (p.i.). Thirty minutes p.i., the gadomelitol tumor distribution evaluated by autoradiography showed a marked difference between the rim and the center, whereas both areas showed comparable concentrations after 3 h. Using dynamic contrast-enhanced MRI, three phases could be observed during the 1 hour observation period: (1) rapid tumor uptake within the first few minutes post-injection (2) a progressive increase in tumor signal enhancement over 10 min and (3) a steady-state phase. Average +/− SD (n=5) transendothelial permeability K^PS and the fractional blood volume fBV were 12.2±1.6 μl/min⁻¹/g and 5.4±0.2% respectively. Due to its slow extravasation and high tumor residence time, gadomelitol may potentially be useful to improve characterization between benign versus malignant tumors using dynamic MRI.