When to sweat: A history of chemotherapy in malignant sweat gland tumors. A unique case report and literature review.

Sarcomatoid sweat gland carcinomas are rare among cutaneous cancers, with less than 20 cases described. A 54-year-old woman with sarcomatoid sweat gland carcinoma of the right upper extremity suffered extensive recurrence at 15 months, unresponsive to chemotherapy. There is no standard treatment or chemotherapy regimens for metastatic sweat gland carcinoma.

First-Principles Prediction of Surface Wetting.

We have developed a method for predicting the solvation contribution to solid-liquid interfacial tension (IFT) based on density functional theory and the implicit solvent model COSMO-RS. Our method can be used to predict wetting behavior for a solid surface in contact with two liquids. We benchmarked our method against measurements of contact angle from water-in-oil on silica wafers and a range of self-assembled monolayers (SAMs) with different compositions, ranging from oil-wet to water-wet. We also compared our predictions to literature data for wetting of a polydimethylsilane surface. By explicitly including deprotonation for silica surfaces and carboxylic acid SAMs, very good agreement was obtained with experimental data for nearly all surfaces. Poor agreement was found for amine-terminated SAMs, which could be the result of both method and model insufficiencies and impurities known to be present for such surfaces. Solid-liquid IFT cannot be measured directly, making predictions such as from our method all the more important.

Minimal methylation classifier (MIMIC): A novel method for derivation and rapid diagnostic detection of disease-associated DNA methylation signatures.

Rapid and reliable detection of disease-associated DNA methylation patterns has major potential to advance molecular diagnostics and underpin research investigations. We describe the development and validation of minimal methylation classifier (MIMIC), combining CpG signature design from genome-wide datasets, multiplex-PCR and detection by single-base extension and MALDI-TOF mass spectrometry, in a novel method to assess multi-locus DNA methylation profiles within routine clinically-applicable assays. We illustrate the application of MIMIC to successfully identify the methylation-dependent diagnostic molecular subgroups of medulloblastoma (the most common malignant childhood brain tumour), using scant/low-quality samples remaining from the most recently completed pan-European medulloblastoma clinical trial, refractory to analysis by conventional genome-wide DNA methylation analysis. Using this approach, we identify critical DNA methylation patterns from previously inaccessible cohorts, and reveal novel survival differences between the medulloblastoma disease subgroups with significant potential for clinical exploitation.

Controlling biomineralisation with cations.

The production of polymers for controlling calcite growth is a well-known approach in biomineralising organisms. Numerous studies have shown that polymers significantly influenced the growth rate and morphology of CaCO3 but little is known about how the polymers are actually controlled by the organisms. Here we show that cations control the effect of polysaccharides and that these processes have been in place for at least 60 million years. We studied the interaction between cleaved samples of pure calcite and ancient coccolith associated polysaccharides (aPS) that we had extracted from the samples of Cretaceous chalk, in solutions that contained one of the common seawater cations, K+, Ca2+, Mg2+ and Sr2+. With atomic and chemical force microscopy (AFM and CFM), we showed that K+, Ca2+ and Sr2+ complex aPS through a weak, outer sphere bonding, giving the aPS affinity to sites on steps and terraces. In contrast, Mg2+ enhanced the formation of stronger and longer aPS complexes, resulting in low affinity to calcite terraces and strong affinity to steps. It is known that adsorption is influenced by ionic potential and ionic strength. Our results show that cation-polysaccharide complexing can modify the effectiveness of the polymer. Thus, creating organic molecules with cation complexing ability is an effective strategy for regulating mineral growth, both now and in the past.

The effect of ionic strength on oil adhesion in sandstone--the search for the low salinity mechanism.

Core flood and field tests have demonstrated that decreasing injection water salinity increases oil recovery from sandstone reservoirs. However, the microscopic mechanism behind the effect is still under debate. One hypothesis is that as salinity decreases, expansion of the electrical double layer decreases attraction between organic molecules and pore surfaces. We have developed a method that uses atomic force microscopy (AFM) in chemical force mapping (CFM) mode to explore the relationship between wettability and salinity. We functionalised AFM tips with alkanes and used them to represent tiny nonpolar oil droplets. In repeated measurements, we brought our "oil" close to the surface of sand grains taken from core plugs and we measured the adhesion between the tip and sample. Adhesion was constant in high salinity solutions but below a threshold of 5,000 to 8,000 ppm, adhesion decreased as salinity decreased, rendering the surface less oil wet. The effect was consistent, reproducible and reversible. The threshold for the onset of low salinity response fits remarkably well with observations from core plug experiments and field tests. The results demonstrate that the electric double layer force always contributes at least in part to the low salinity effect, decreasing oil wettability when salinity is low.

Interactions of Na+, K+, Mg2+, and Ca2+ with benzene self-assembled monolayers.

Interactions between cations and organic molecules are found throughout nature, from the functionality and structure of proteins in humans and animals to the exchange of ions in minerals in soil and oil reservoirs with the fluid phases. We have explored the behavior of the s-block elements that are most common in the natural world, namely, Na(+), K(+), Mg(2+), and Ca(2+). Specifically, we investigated how these ions affect the interactions between surfaces covered by self-assembled monolayers (SAMs) terminated with benzene molecules. We used a flat oxidized silicon substrate and an atomic force microscopy (AFM) tip that were both functionalized with 11-phenoxyundecane-1-thiol and measured the adhesion force between them in solutions of each of the four chloride salts. We observed that the adhesion increased in the order of the Hofmeister series: K(+) < Na(+) ≈ Mg(2+) < Ca(2+). Supplementary evidence from X-ray photoelectron spectroscopy (XPS) allowed us to conclude that K(+) binds in the benzene layers, creating a positive surface charge on the benzene-covered surfaces, thus leading to lower adhesion in KCl solutions than in pure water. Evidence suggested that Ca(2+) does not bind to the surfaces but forms bridges between the layers, leading to higher adhesion than in pure water. In Na(+) and Mg(2+) solutions, adhesion is quite similar to that in pure water, indicating a lack of interaction between these two ions and the surfaces, or at least that the interaction is too weak to be detected by our measurements. The results of our studies clearly show that even a nonpolar, hydrophobic molecule, such as benzene, has a role to play in the behavior of aqueous solutions and that it interacts differently depending on which ions are present. Even ions from the same column in the periodic table behave differently.

Role of steps in the dissociative adsorption of water on rutile TiO2(110).

The water-TiO(2) interaction is of paramount importance for many processes occurring on TiO(2), and the rutile TiO(2)(110)-(1×1) surface has often been considered as a test case. Yet, no consensus has been reached whether the well-studied surface O vacancies on the terraces are the only active sites for water dissociation on rutile TiO(2)(110)-(1 × 1), or whether another channel for the creation of H adatoms exists. Here we use high-resolution scanning tunneling microscopy and density functional theory calculations to tackle this long-standing question. Evidence is presented that a second water dissociation channel exists on the surfaces of vacuum-annealed TiO(2)(110) crystals that is associated with the ⟨111⟩ step edges. This second water dissociation channel can be suppressed by blocking of the ⟨111⟩ step edges using ethanol.

Formation and diffusion of water dimers on rutile TiO2(110).

From an interplay of time-lapsed high resolution scanning tunneling microscopy and density functional theory calculations we reveal the formation and diffusion of water dimers on hydrated rutile TiO2(110)-(1x1) surfaces, i.e., surfaces containing OH_{br} groups. At temperatures between approximately 150 and approximately 210 K water monomers diffusing along the Ti troughs were found to form stable water dimers that diffuse faster than the water monomers. An H bond mediated rollover mechanism operating for the water dimers explains the experimental findings.

Enhanced bonding of gold nanoparticles on oxidized TiO2(110).

We studied the nucleation of gold clusters on TiO2(110) surfaces in three different oxidation states by high-resolution scanning tunneling microscopy. The three TiO2(110) supports chosen were (i) reduced (having bridging oxygen vacancies), (ii) hydrated (having bridging hydroxyl groups), and (iii) oxidized (having oxygen adatoms). At room temperature, gold nanoclusters nucleate homogeneously on the terraces of the reduced and oxidized supports, whereas on the hydrated TiO2(110) surface, clusters form preferentially at the step edges. From interplay with density functional theory calculations, we identified two different gold-TiO2(110) adhesion mechanisms for the reduced and oxidized supports. The adhesion of gold clusters is strongest on the oxidized support, and the implications of this finding for catalytic applications are discussed.

Formation and splitting of paired hydroxyl groups on reduced TiO2(110).

A combination of high-resolution scanning tunneling microscopy and density functional theory is utilized to study the interaction of water with the reduced TiO2(110)-(1 x 1) surface. As the direct product of water dissociation in oxygen vacancies, paired hydroxyl groups are formed. These pairs are immobile and stable unless they interact with adsorbed water molecules. As a result of these interactions, protons are transferred to adjacent oxygen rows, thereby forming single hydroxyl groups. Additionally, we show that hydroxyl groups facilitate the diffusion of water molecules over the oxygen rows.

Oxidation of Pt(110).

Using scanning tunneling microscopy and temperature programmed desorption we investigate the Pt(110) surface under strongly oxidizing conditions involving either high-pressure O2 or atomic oxygen exposure. At low temperatures, only disordered Pt oxide structures are observed. After annealing ordered surface oxide islands are observed to coexist with a highly stable reconstructed (12x2)-O chemisorption structure. From density functional theory calculations a model for the surface oxide phase is revealed. The phase is found to be metastable, and its presence is explained in terms of stabilizing defects in the chemisorption layer and reduced Pt mobility.