Evaluation of the use of liquid dishwashing compounds to control bacteria in kitchen sponges

A test procedure for evaluating the effect of adding commercial liquid hand dishwashing detergents to kitchen sponges to control microbial growth is described. Claims for this type of application are being made on dishwashing detergents throughout the world. In this evaluation, commercially available kitchen sponges were stripped of antimicrobial compounds. Sponges were then inoculated with a pool of 7 microorganisms which consisted of gram positives, gram negatives, and yeast. Inoculated sponges were treated with the detergent as recommended by the manufacturer and allowed to incubate for 16 h at ambient temperature. Surviving microorganisms were then quantitated using either the spiral or pour plate method. Tests were run using both clean sponges and sponges soiled with 0.5% nonfat dry milk (NFDM). Untreated sponges showed stasis or slightly increased bacterial populations after the incubation period in the absence of NFDM. Significant increases of up to 3 log cfu/mL were observed for untreated sponges when soiled with NFDM. Statistically significant reductions were observed for clean sponges (99.8-99.9998%) and sponges soiled with NFDM (87.6-99.9%) when detergents making "antibacterial sponge" claims were added to the inoculated sponges. Statistically significant differences between detergents making "antibacterial sponge" claims were also observed.     

On a combinatorial method for counting smooth numbers in sets of integers

In this paper we develop a method for determining the number of integers without large prime factors lying in a given set S. We will apply it to give an easy proof that certain sufficiently dense sets A and B always produce the expected number of “smooth” sums a+b, a∈A, b∈B. The proof of this result is completely combinatorial and elementary.     

On classification of four-dimensional nilpotent Leibniz algebras

Leibniz algebras are certain generalization of Lie algebras. In this paper, we give the classification of four-dimensional non-Lie nilpotent Leibniz algebras. We use the canonical forms for the congruence classes of matrices of bilinear forms and some other techniques to obtain our result.     

Monads in topology

Let T be a submonad of the ultrafilter monad β and let G be a subfunctor of the filter functor. The T-algebras are topological spaces whose closed sets are the subalgebras and form thereby an equationally definable full subcategory of topological spaces. For appropriate T, countably generated free algebras provide ZFC examples of separable, Urysohn, countably compact, countably tight spaces which are neither compact nor sequential, and c² non-homeomorphic such examples exist. For any space X, say that U⊂X is G-open if U belongs to every ultrafilter in GX which converges in U. The full subcategory TopG consists of all G-spaces, those spaces in which every G-open set is open. Each TopG has at least these stability properties: it contains all Alexandroff spaces, and is closed under coproducts, quotients and locally closed subspaces. Examples include sequential spaces, P-spaces and countably tight spaces. T-algebras are characterized as the T-compact, T-Hausdorff T-spaces. Malyhin's theorem on countable tightness generalizes verbatim to TopG for any G⊂β. For r∈ω^?=βω\ω, let Gr be the subfunctor of β generated by r and let Tr be the generated submonad. If RK_? is the Rudin-Keisler preorder on ω^?, rRK_?s⇔Gr⊂Gs. Let c_? be the Comfort preorder and define the monadic preorderrm_?s to mean Tr⊂Ts. Then rRK_?s⇒rm_?s⇒rc_?s. It follows that there exist c² monadic types. For each such type Tr, the Tr-algebras form an equationally definable full subcategory of topological spaces with only one operation of countably infinite arity. No two of these varieties are term equivalent nor is any one a full subcategory of another inside topological spaces. Say that r∈ω^? is an m-point if Gr≠Tr. Under CH, m-points exist.     

Science at the Hard X-ray Diffraction Limit (XDL2011), Part 1

There is growing excitement in the synchrotron materials science community about the potential of nearly diffraction-limited, high-repetition rate, hard X-ray sources, such as an Energy Recovery Linac (ERL) or an Ultimate Storage Ring (USR), and that these sources will pave the way to scientific insights and discoveries not possible with existing facilities. These future sources will deliver highly coherent, nearly diffraction-limited X-ray beams that will power ultra-intense, nanometer-scale X-ray probes and imaging capabilities approaching atomic resolution. They will produce X-ray pulses at MHz to GHz repetition rates and span pulse durations from below 50 femtoseconds to tens of picoseconds, enabling new classes of experiments in hard X-ray science.     

Classification of Some Solvable Leibniz Algebras

Leibniz algebras are certain generalization of Lie algebras. In this paper we give classification of non-Lie solvable (left) Leibniz algebras of dimension ≤ 8 with one dimensional derived subalgebra. We use the canonical forms for the congruence classes of matrices of bilinear forms to obtain our result. Our approach can easily be extended to classify these algebras of higher dimensions. We also revisit the classification of three dimensional non-Lie solvable (left) Leibniz algebras.     

Synthesis and in Vitro Evaluation of New Cephalosporins Exhibiting Antimicrobial Activity against Gram-Positive Bacteria,in Particular Methicillin-Resistant Staphylococci

The preparation and biological evaluation of 7β-[[2-(phenyl)thiazol-4-yl]acetamido]cephalosporins and 7β-[[(2-(pyridin-2-yl)thiazol-4-yl]acetamido]cephalosporins, 9a-o , substituted at the 3-position with acetyloxymethyl, chlorine, hydrogen, and methyl are described. Hantzsch's thiazole synthesis is employed to provide thiazoleacetic acids 5a-e , subsequently followed by Morpho CDI-assisted amidation to complete the synthesis of target cephalosporins 9a-o . These compounds display activity selectively against Gram-positive bacteria, but are inactive against most Gram-negative bacteria tested. Those with acetyloxymethyl at the 3-position, i.e., 9a, 9e, 9i, 9m , and 90 , exhibit activity with minimal inhibitory concentrations of 16 (μg/mL or lower against four strains of methicillin-resistant staphylococci, namely Staphylococcus aureus X400 and S13E and Staphylococcus epidermidis 270 and 222. Notably, 9a displays an activity profile similar to that of vancomycin regarding its spectrum and potency.