Nomenclature of structural and compositional characteristics of ordered microporous and mesoporous materials with inorganic hosts(IUPAC Recommendations 2001)

A system of terms applicable to ordered microporous and mesoporous materials is proposed, and rules for writing a standardized crystal chemical formula for such materials are presented. The recommendations are based both on common usage and on a systematic classification scheme. The nomenclature has been developed to encompass all inorganic materials with ordered, accessible pores with free diameters of less than 50 nm. The crystal chemical formula describes the chemical composition of both the guest species and the host, the structure of the host, the structure of the pore system, and the symmetry of the material. This formula can be simplified or expanded to suit the user's requirement

The cosmic ray spectrum above 10(17) eV

The final analysis of the data obtained by the Sydney University Giant Airshower Recorder (SUGAR) is presented. The data has been reanalysed to take into account the effects of afterpulsing in the photomultiplier tubes. Event data was used to produce a spectrum of equivalent vertical muon number and from this a model dependent primary energy spectrum was obtained. These spectra show good evidence for the Ankle: a flattening at 10(19) eV. There is no sign of the cut-off which would be expected from the effects of the universal black body radiation

Detection-Loophole-Free Test of Quantum Nonlocality, and Applications

We present a source of entangled photons that violates a Bell inequality free of the "fair-sampling" assumption, by over 7 standard deviations. This violation is the first experiment with photons to close the detection loophole, and we demonstrate enough "efficiency" overhead to eventually perform a fully loophole-free test of local realism. The entanglement quality is verified by maximally violating additional Bell tests, testing the upper limit of quantum correlations. Finally, we use the source to generate secure private quantum random numbers at rates over 4 orders of magnitude beyond previous experiments.Comment: Main text: 5 pages, 2 figures, 1 table. Supplementary Information: 7 pages, 2 figure

Location of Ge and extra-framework species in the zeolite ITQ-24

The germanosilicate ITQ-24 (IWR framework type) was synthesized in fluoride medium using 1,3,5-tris(1,2-dimethylimidazolium) benzene as the structure directing agent (SDA). A structure analysis of the as-synthesized ITQ-24 material using synchrotron powder diffraction data and difference electron density calculations have allowed the fluoride ions and the germanium atoms to be located and the conformation of the SDA to be determined. The benzyl ring is perpendicular to the b axis with the three imidazolium moieties forming a “T-shaped” arrangement. Ge atoms replace some of the Si in the double-4-ring (d4r) and in one of the single-4-rings (s4r). The other s4r contains only Si. Fluoride ions are in the d4r units. Initially, the space group Cmmm (highest possible symmetry) was assumed, but the framework geometry was strained. An independent evaluation of the symmetry using the powder charge flipping algorithm in Superflip led to a successful refinement with reasonable geometry and a refined composition of |[(C_6H_3)(C_7H_(10)N_2)_3]_2F_2|[Si_(40.2)Ge_(15.8)O_(112)] in the space group Pban

Gaps in detailed knowledge of human papillomavirus (HPV) and the HPV vaccine among medical students in Scotland

<p>Background: A vaccination programme targeted against human papillomavirus (HPV) types16 and 18 was introduced in the UK in 2008, with the aim of decreasing incidence of cervical disease. Vaccine roll out to 12–13 year old girls with a catch-up programme for girls aged up to 17 years and 364 days was accompanied by a very comprehensive public health information (PHI) campaign which described the role of HPV in the development of cervical cancer.</p> <p>Methods: A brief questionnaire, designed to assess acquisition of knowledge of HPV infection and its association to cervical cancer, was administered to two different cohorts of male and female 1st year medical students (school leavers: 83% in age range 17–20) at a UK university. The study was timed so that the first survey in 2008 immediately followed a summer's intensive PHI campaign and very shortly after vaccine roll-out (150 students). The second survey was exactly one year later over which time there was a sustained PHI campaign (213 students).</p> <p>Results: We addressed three research questions: knowledge about three specific details of HPV infection that could be acquired from PHI, whether length of the PHI campaign and/or vaccination of females had any bearing on HPV knowledge, and knowledge differences between men and women regarding HPV. No female student in the 2008 cohort had completed the three-dose vaccine schedule compared to 58.4% of female students in 2009. Overall, participants’ knowledge regarding the sexually transmitted nature of HPV and its association with cervical cancer was high in both year groups. However, in both years, less than 50% of students correctly identified that HPV causes over 90% of cases of cervical cancer. Males gave fewer correct answers for these two details in 2009. In 2008 only around 50% of students recognised that the current vaccine protects against a limited subset of cervical cancer-causing HPV sub-types, although there was a significant increase in correct response among female students in the 2009 cohort compared to the 2008 cohort.</p> <p>onclusions: This study highlights a lack of understanding regarding the extent of protection against cervical cancer conferred by the HPV vaccine, even among an educated population in the UK who could have a vested interest in acquiring such knowledge. The intensive PHI campaign accompanying the first year of HPV vaccination seemed to have little effect on knowledge over time. This is one of the first studies to assess detailed knowledge of HPV in both males and females. There is scope for continued improvements to PHI regarding the link between HPV infection and cervical cancer.</p&gt

Structure of the C-terminal domain of the Prokaryotic Sodium Channel Orthologue NsvBa

Crystallographic and electrophysiological studies have recently provided insight into the structure, function and drug binding of prokaryotic sodium channels. These channels exhibit significant sequence identities, especially in their transmembrane regions, with human voltage-gated sodium channels. However, rather than being single polypeptides with four homologous domains, they are tetramers of single domain polypeptides, with a C-terminal domain (CTD) composed of an inter-subunit four helix coiled-coil. The structures of the CTDs differ between orthologues. In NavBh and NavMs, the C-termini form a disordered region adjacent to the final transmembrane helix, followed by a coiled-coil region, as demonstrated by synchrotron radiation circular dichroism (SRCD) and double electron-electron resonance electron paramagnetic resonance spectroscopic measurements. In contrast, in the crystal structure of the NavAe orthologue, the entire C-terminus is comprised of a helical region followed by a coiled-coil. In this study we have examined the CTD of the NsvBa from Bacillus alcalophilus, which unlike other orthologues is predicted by different methods to have different types of structures: either a disordered adjacent to the transmembrane region, followed by a helical coiled-coil, or a fully helical CTD. To discriminate between the two possible structures we have used SRCD spectroscopy to experimentally determine the secondary structure of the C-terminus of this orthologue and used the results as the basis for modelling the transition between open and closed conformations of the channel

The global prevalence of Huntington’s disease: a systematic review and discussion

The ascertained prevalence of Huntington's disease (HD) increased significantly following the provision of diagnostic testing. A systematic review was conducted to estimate the prevalence of HD in the post-diagnostic testing era. Twenty-two studies with original data pertaining to the prevalence of HD (1993–2015) were included and analyzed. A global meta-analysis was not performed due to heterogeneity in study methods and geographical variation. The prevalence of HD is significantly lower in Asian populations compared with western Europe, North America and Australia. The global variation in HD prevalence is partly explained by the average CAG repeat lengths and frequency of different HTT gene haplotypes in the general population. Understanding the prevalence of HD has significant implications for healthcare resource planning

High Latitude Dynamics of Atmosphere-Ice-Ocean Interactions

Dynamics of atmosphere–ice–ocean interactions in the high latitudes. What: Scientists from 13 countries involved with modeling and observing the coupled high-latitude weather and climate system discussed our current understanding and challenges in polar prediction, extreme events, and coupled processes on scales ranging from cloud and turbulent processes, from micrometers and a few hundred meters to processes on synoptic-scale weather phenomena and pan-Arctic energy budgets of hundreds to thousands of kilometers. Workshop participants also evaluated research needs to improve numerical models with usages spanning from uncoupled to fully coupled models used for weather and climate prediction (http://highlatdynamics.b.uib.no/). When: 23–27 March 2015. Where: Rosendal, Norwa

Differential lipid dependence of the function of bacterial sodium channels

The lipid bilayer is important for maintaining the integrity of cellular compartments and plays a vital role in providing the hydrophobic and charged interactions necessary for membrane protein structure, conformational flexibility and function. To directly assess the lipid dependence of activity for voltage-gated sodium channels, we compared the activity of three bacterial sodium channel homologues (NaChBac, NavMs, and NavSp) by cumulative 22Na+ uptake into proteoliposomes containing a 3:1 ratio of 1-palmitoyl 2-oleoyl phosphatidylethanolamine and different “guest” glycerophospholipids. We observed a unique lipid profile for each channel tested. NavMs and NavSp showed strong preference for different negatively-charged lipids (phosphatidylinositol and phosphatidylglycerol, respectively), whilst NaChBac exhibited a more modest variation with lipid type. To investigate the molecular bases of these differences we used synchrotron radiation circular dichroism spectroscopy to compare structures in liposomes of different composition, and molecular modeling and electrostatics calculations to rationalize the functional differences seen. We then examined pore-only constructs (with voltage sensor subdomains removed) and found that in these channels the lipid specificity was drastically reduced, suggesting that the specific lipid influences on voltage-gated sodium channels arise primarily from their abilities to interact with the voltage-sensing subdomains

A tetragonal-to-monoclinic phase transition in a ferroelectric perovskite: the structure of PbZr(0.52)Ti(0.48)O3

The perovskite-like ferroelectric system PbZr(1-x)Ti(x)O3 (PZT) has a nearly vertical morphotropic phase boundary (MPB) around x=0.45-0.50. Recent synchrotron x-ray powder diffraction measurements by Noheda et al. [Appl. Phys. Lett. 74, 2059 (1999)] have revealed a new monoclinic phase between the previously-established tetragonal and rhombohedral regions. In the present work we describe a Rietveld analysis of the detailed structure of the tetragonal and monoclinic PZT phases on a sample with x= 0.48 for which the lattice parameters are respectively: at= 4.044 A, ct= 4.138 A, at 325 K, and am= 5.721 A, bm= 5.708 A, cm= 4.138 A, beta= 90.496 deg., at 20K. In the tetragonal phase the shifts of the atoms along the polar [001] direction are similar to those in PbTiO3 but the refinement indicates that there are, in addition, local disordered shifts of the Pb atoms of ~0.2 A perpendicular to the polar axis.. The monoclinic structure can be viewed as a condensation along one of the directions of the local displacements present in the tetragonal phase. It equally well corresponds to a freezing-out of the local displacements along one of the directions recently reported by Corker et al.[J. Phys. Condens. Matter 10, 6251 (1998)] for rhombohedral PZT. The monoclinic structure therefore provides a microscopic picture of the MPB region in which one of the "locally" monoclinic phases in the "average" rhombohedral or tetragonal structures freezes out, and thus represents a bridge between these two phases.Comment: REVTeX, 7 figures. Modifications after referee's suggestion: new figure (figure 5), comments in 2nd para. (Sect.III) and in 2nd & 3rd para. (Sect. IV-a), in the abstract: "...of ~0.2 A perpendicular to the polar axis.