Degradation of C<Emphasis Type="Italic">andida albicans</Emphasis> on TiO<Subscript>2</Subscript> and Ag-TiO<Subscript>2</Subscript> thin films prepared by sol–gel and nanosuspensions

In this study, both suspensions and thin films of TiO₂ and silver loaded TiO₂ (Ag-TiO₂) were used in the photocatalytic degradation/disinfection of C. albicans. In the case of thin films coated materials, both microscope slides and steel pieces of similar dimensions were dip coated using sol–gel solutions prepared from titanium isopropoxide. Surface analysis of the materials confirmed that thin film formation had been succesful. After set periods of irradiation in the presence of suspension or thin film coated material, 10 μL aliquots of the solution were withdrawn and directly cultivated on sabouraud dextrose agar for 24 h at 37 °C. The number of living colonies was counted. The results show that both the suspensions and the thin films displayed superior antimicrobial properties towards C. albicans. In particular the Ag-TiO₂ catalyst was extremely active even in the dark, for disinfection of C. albicans. The degradation percentage over TiO₂ and Ag-TiO₂ thin films coated on the steel substrate was higher than those coated on glass achieving 80 and 97.9%, respectively, using the 365 nm, near visible region light source.     

Throttling for the game of Cops and Robbers on graphs

We consider the cop-throttling number of a graph $G$ for the game of Cops and Robbers, which is defined to be the minimum of $(k+{\mathrm{capt}}_k\left(G\right))$, where $k$ is the number of cops and ${\mathrm{capt}}_k\left(G\right)$ is the minimum number of rounds needed for $k$ cops to capture the robber on $G$ over all possible games. We provide some tools for bounding the cop-throttling number, including showing that the positive semidefinite (PSD) throttling number, a variant of zero forcing throttling, is an upper bound for the cop-throttling number. We also characterize graphs having low cop-throttling number and investigate how large the cop-throttling number can be for a given graph. We consider trees, unicyclic graphs, incidence graphs of finite projective planes (a Meyniel extremal family of graphs), a family of cop-win graphs with maximum capture time, grids, and hypercubes. All the upper bounds on the cop-throttling number we obtain for families of graphs are $O\left(\sqrt{n}\right)$.     

Staircase kernels in orthogonal polygons

Supported in part by NSF grant DMS-8908717 and by a Senior Faculty Summer Research Fellowship, Research Council, University of Oklahoma.     

A helly-number fork-almost-neighborly sets

It is possible to prove the following “Helly-type” thorem fork-almost-neighborly sets. Theorem.A ⊆R ^d is k-almost-neighborly if and only if every 2d+1 member subset of A is k-almost-neighborly. Moreover, if A ⊆bdry conv A, then A is k-almost-neighborly if and only if every 2d member subset of A is k-almost-neighborly. Each bound is best possible.     

Families of planar sets having starlike union

Let be a finite family of compact sets in the plane, and letk be a fixed natural number. If every three (not necessarily distinct) members of have a union which is simply connected and starshaped viak-paths, then and is starshaped viak-paths. Analogous results hold for paths of length at most , > 0, and for staircase paths, although not for staircasek-paths.Supported in part by NSF grant DMS-9504249     

Unions of Sets Starshaped via Staircase Paths or via Paths of Bounded Length

Let S be an orthogonal polygon in the plane, S simply connected, and let k=2,3. Set S is a union of k sets starshaped via staircase paths if and only if for every F finite, F bdry S, there is a set G bdry S arbitrarily close to F and points si,1 ik, (depending on G) such that each point of G is clearly visible from some si. An analogous result holds for a union of 2 sets starshaped via -paths when S is a closed simply connected set in the plane. Each result is best possible.     

Awareness of genetic testing for increased cancer risk in the year 2000 National Health Interview Survey

OBJECTIVES: This study explores factors associated with differential awareness of genetic tests for increased cancer risk in the US. METHODS: 27,405 respondents from the 2000 National Health Interview Survey, ages 25+, were asked if they had heard of these tests. RESULTS: 44.4% said 'yes', including 49.9% of whites, 32.9% of African-Americans, 32.3% of American Indians/Alaskan Natives, 28.0% of Asian/Pacific Islanders, and 20.6% of Hispanics. In multivariate analysis, test awareness was significantly associated with higher education, white race, age <60 years, female gender, private health insurance, personal or parent's history of certain cancers, physical activity, and vitamin/supplement use, among other factors. CONCLUSIONS: The survey showed which population subgroups may lack access to cancer genetics information and may therefore benefit from targeted strategies to ensure risk-appropriate utilization of genetic counseling and testing.     

Design,Synthesis and Structural Analysis of Glucocerebrosidase Imaging Agents

Gaucher disease (GD) is a lysosomal storage disorder caused by inherited deficiencies in β-glucocerebrosidase (GBA). Current treatments require rapid disease diagnosis and a means of monitoring therapeutic efficacy, both of which may be supported by the use of GBA-targeting activity-based probes (ABPs). Here, we report the synthesis and structural analysis of a range of cyclophellitol epoxide and aziridine inhibitors and ABPs for GBA. We demonstrate their covalent mechanism-based mode of action and uncover binding of the new N-functionalised aziridines to the ligand binding cleft. These inhibitors became scaffolds for the development of ABPs; the O6-fluorescent tags of which bind in an allosteric site at the dimer interface. Considering GBA's preference for O6- and N-functionalised reagents, a bi-functional aziridine ABP was synthesized as a potentially more powerful imaging agent. Whilst this ABP binds to two unique active site clefts of GBA, no further benefit in potency was achieved over our first generation ABPs. Nevertheless, such ABPs should serve useful in the study of GBA in relation to GD and inform the design of future probes.     

Sterically demanding macrocyclic Eu(iii) complexes for selective recognition of phosphate and real-time monitoring of enzymatically generated adenosine monophosphate

The design of molecular receptors that bind and sense anions in biologically relevant aqueous solutions is a key challenge in supramolecular chemistry. The recognition of inorganic phosphate is particularly challenging because of its high hydration energy and pH dependent speciation. Adenosine monophosphate (AMP) represents a valuable but elusive target for supramolecular detection because of its structural similarity to the more negatively charged anions, ATP and ADP. We report two new macrocyclic Eu(iii) receptors capable of selectively sensing inorganic phosphate and AMP in water. The receptors contain a sterically demanding 8-(benzyloxy)quinoline pendant arm that coordinates to the metal centre, creating a binding pocket suitable for phosphate and AMP, whilst excluding potentially interfering chelating anions, in particular ATP, bicarbonate and lactate. The sensing selectivity of our Eu(iii) receptors follows the order AMP > ADP > ATP, which represents a reversal of the order of selectivity observed for most reported nucleoside phosphate receptors. We have exploited the unique host–guest induced changes in emission intensity and lifetime for the detection of inorganic phosphate in human serum samples, and for monitoring the enzymatic production of AMP in real-time.

We present two new europium-based anion receptors that selectively bind to inorganic phosphate and AMP in aqueous media. Their sensing selectivity follows the order AMP > ADP > ATP, representing a reversal of the selectivity order observed for most nucleoside phosphate receptors.