No abstract

NCT00890708.

Self-assembled monolayers (SAMs) were prepared by the adsorption of a series of 2,2-dialkylpropane-1,3-dithiols (1-5) and 2-pentadecylpropane-1,3-dithiol (6) onto the surface of gold. These SAMs were characterized by ellipsometry, contact angle goniometry, X-ray photoelectron spectroscopy (XPS), polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), and atomic force microscopy (AFM).The studies demonstrate that a systematic variation in the structure of R′RC(CH 2 SH) 2 from symmetrical (1; R′ ) R) to progressively more unsymmetrical (2-6; R′ * R) can be used to provide control over the conformational order and interchain packing of the hydrocarbon tail group assembly. The tail group conformation and packing were found to influence profoundly both the wettability and the tribological properties of the SAMs. Assemblies of well-ordered, well-packed hydrocarbon tail groups yielded interfaces that exhibited low wettabilities and low frictional responses when compared to assemblies of disordered, loosely packed hydrocarbon tail groups. The trends in wettability and friction were rationalized by considering the magnitude of the van der Waals interactions between the hydrocarbon film and the contacting probe liquid and AFM tip, respectively.

Atomically thin two-dimensional materials have emerged as promising candidates for flexible and transparent electronic applications. Here we show non-volatile memory devices, based on field-effect transistors with large hysteresis, consisting entirely of stacked two-dimensional materials. Graphene and molybdenum disulphide were employed as both channel and charge-trapping layers, whereas hexagonal boron nitride was used as a tunnel barrier. In these ultrathin heterostructured memory devices, the atomically thin molybdenum disulphide or graphene-trapping layer stores charge tunnelled through hexagonal boron nitride, serving as a floating gate to control the charge transport in the graphene or molybdenum disulphide channel. By varying the thicknesses of two-dimensional materials and modifying the stacking order, the hysteresis and conductance polarity of the field-effect transistor can be controlled. These devices show high mobility, high on/off current ratio, large memory window and stable retention, providing a promising route towards flexible and transparent memory devices utilizing atomically thin two-dimensional materials.

Robotic thyroidectomy is a safe, feasible, and cosmetically excellent procedure in properly selected patients with PTC.

Natural killer (NK) cells have the potential to deliver both direct antimicrobial effects and regulate adaptive immune responses, but NK cell yields have been reported to vary greatly during different viral infections. Activating receptors, including the Ly49H molecule recognizing mouse cytomegalovirus (MCMV), can stimulate NK cell expansion. To define Ly49H's role in supporting NK cell proliferation and maintenance under conditions of uncontrolled viral infection, experiments were performed in Ly49h−/−, perforin 1 (Prf1)−/−, and wild-type (wt) B6 mice. NK cell numbers were similar in uninfected mice, but relative to responses in MCMV-infected wt mice, NK cell yields declined in the absence of Ly49h and increased in the absence of Prf1, with high rates of proliferation and Ly49H expression on nearly all cells. The expansion was abolished in mice deficient for both Ly49h and Prf1 (Ly49h−/−Prf1−/−), and negative consequences for survival were revealed. The Ly49H-dependent protection mechanism delivered in the absence of Prf1 was a result of interleukin 10 production, by the sustained NK cells, to regulate the magnitude of CD8 T cell responses. Thus, the studies demonstrate a previously unappreciated critical role for activating receptors in keeping NK cells present during viral infection to regulate adaptive immune responses.

Alkanethiols possessing terminal phenyl groups (C6H5(CH2)nSH, n ) 12-15) were adsorbed onto the surface of gold to afford phenyl-terminated self-assembled monolayers (SAMs). The SAMs were characterized by optical ellipsometry, polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), atomic force microscopy (AFM), and contact angle goniometry. The films generated from the phenylterminated alkanethiols exhibited greater thicknesses but similar crystallinities and well-ordered lattice structures when compared to analogous SAMs generated by the adsorption of normal alkanethiols onto gold. Advancing contact angle measurements using water as the test liquid supported the presence of interfacial phenyl moieties. Furthermore, contact angle measurements using the test liquids methylene iodide (MI), dimethyl formamide (DMF), and nitrobenzene (NB) revealed an odd-even effect as a function of the number of methylene units underneath the terminal phenyl groups. The tribological properties of the phenyl-terminated films were characterized by AFM and compared to those of films derived from normal alkanethiols and other materials presenting aromatic hydrocarbon moieties at the interface (i.e., graphite and C60). The phenyl-terminated SAMs exhibited a substantially higher frictional response than graphite, a slightly higher frictional response than normal alkanethiol SAMs, but a much lower frictional response than C60-terminated SAMs.

In inbred mouse strains, permissiveness to intracellular replication of Legionella pneumophila is controlled by a single locus (Lgn1), which maps to a region within distal Chromosome 13 that contains multiple copies of the gene baculoviral IAP repeat-containing 1 (Birc1, also called Naip; refs. 1-3). Genomic BAC clones from the critical interval were transferred into transgenic mice to functionally complement the Lgn1-associated susceptibility of A/J mice to L. pneumophila. Here we report that two independent BAC clones that rescue susceptibility have an overlapping region of 56 kb in which the entire Lgn1 transcript must lie. The only known full-length transcript coded in this region is Birc1e (also called Naip5).