Atomic refinement with correlated solid-state NMR restraints

The orientation data provided by solid-state NMR can provide a great deal of structural information about membrane proteins. The quality of the information provided is, however, somewhat degraded by sign degeneracies in measurements of the dipolar coupling tensor. This is reflected in the dipolar coupling penalty function used in atomic refinement, which is less capable of properly restraining atoms when dipolar sign degeneracies are present. In this report we generate simulated solid-state NMR data using a variety of procedures, including back-calculation from crystal structures of alpha-helical and beta-sheet membrane proteins. We demonstrate that a large fraction of the dipolar sign degeneracies are resolved if anisotropic dipolar coupling measurements are correlated with anisotropic chemical shift measurements, and that all sign degeneracies can be resolved if three data types are correlated. The advantages of correlating data are demonstrated with atomic refinement of two test membrane proteins. When refinement is performed using correlated dipolar couplings and chemical shifts, perturbed structures converge to conformations with a larger fraction of correct dipolar signs than when data are uncorrelated. In addition, the final structures are closer to the original unperturbed structures when correlated data are used in the refinement. Thus, refinement with correlated data leads to improved atomic structures. The software used to correlate dipolar coupling and chemical shift data and to set up energy functions and their derivatives for refinement, CNS-SS02, is available at our web site.     

An I = 1 enhancement at a mass of 1550 MeV in the (Λπ) and (Σπ)-systems

Evidence is presented for an I = 1 enhancement observed in the reactions K^?p→Λ(Σ)K⁰₁K^±π^? at $\text{4.2}\text{GeV}\text{c}$ inciden momentum. The mass and width of the proposed new Y¹ are, respectively, (1553 ± 7) MeV) and (80 ± 30) MeV. A decay branching ratio $\text{Σπ}\text{(Σπ + Λπ)}\text{= (35 ± 12)\%}$ is also obtained.     

A characterization of dilatation analytic integral kernels

We characterize integral operators belonging to B(L ² (ℝ³))which are dilatation analytic in the Cartesian product of two sectors S _a ⊂ ℂ as analytic functions from S _a×S_a into B(L ²(Ω)), the space of bounded operators on square integrable functions on the unit sphere Ω, which satisfy certain norm estimates uniformly on every subsector.     

Study of the reactionsπ − p→K 0(890) Λ,K 0(890)Σ 0 andK 0(890)Σ 0 at 3.95 GeV/c

The reactionsπ ^? p→K ⁰(890) Λ,K ⁰(890)Σ ⁰ andK ⁰(890)Σ ⁰ are studied at an incident momentum of 3.95 GeV/c using data from a high statistics bubble chamber experiment corresponding to ～90 events/μb. The differential cross sections, density matrix elements of the vector meson and hyperon polarizations are presented. A transversity amplitude analysis is performed for each of the reactions. The results are compared with those obtained for the SU(3) related processesK ^? p→?Δ, ?Σ ⁰, ?Σ ⁰(1385) and? ^? Σ ⁺(1385) and with predictions of the additive quark model and SU(6) sum rules.     

SU(3) implications of the observation of the A1 and C mesons

A new determination of the Q_A?Q_B mixing angle and of the antisymmetric coupling for the vector-pseudoscalar decay of the axial vector mesons is presented. This uses information from the decay rates of the A₁ and C mesons found in the study of baryon exchange processes in K^?p interactions at 4.2 GeV/c combined with the decay rate B → ωπ. The consistency between the results obtained from backward produced A₁ and C and diffractively produced Q₁ and Q₂ is discussed.     

Antibody-catalyzed aminolysis of a chloropyrimidine derivative

We have generated antibody FTB8E9 by immunization with the designed hapten to catalyze the aminolysis reaction of a chloropyrimidine derivative.     

Bifurcations of non-smooth systems

Non-smooth systems (namely piecewise-smooth systems) have received much attention in the last decade. Many contributions in this area show that theory and applications (to electronic circuits, mechanical systems, …) are relevant to problems in science and engineering. Specially, new bifurcations have been reported in the literature, and this was the topic of this minisymposium. Thus both bifurcation theory and its applications were included. Several contributions from different fields show that non-smooth bifurcations are a hot topic in research. Thus in this paper the reader can find contributions from electronics, energy markets and population dynamics. Also, a carefully-written specific algebraic software tool is presented.     

On centralized resource utilization and its reallocation by using DEA

The standard DEA model allows different DMU units to set their own priorities for the inputs and outputs that form part of the efficiency assessment. In the case of a centralized organization with many outlets, such as an education authority that is responsible for many schools, it may be more sensible to operate in the most efficient way, but under a common set of priorities for all DMUs. The algorithm that is used to do this, the centralized resource allocation model, does just this. We show that the centralized resource allocation model can be substantially simplified and we interpret the simplifications and show how the model works using real data of Spanish public schools. Apart from finding the best way to reallocate resource among the schools, it is shown that the most desirable operating unit is found to be a by-product of the estimation. This is useful information when planning new schools.     

Effects of polyphenol removal methods on the in vitro exsheathment inhibitory activity of Lysiloma latisiliquum extracts against Haemonchus contortus larvae

It has been suggested that the anthelmintic (AH) activity of tannin-rich forages is related to their tannin content. However, reports on tropical fodders such as Lysiloma latisiliquum describe the same AH activity after the addition of tannin-blocking agents, suggesting that the activity either depends on the method of tannin blocking/removal or is due to other type of secondary metabolites. This study compared both the effect of the drying process of the plant material and the effect of different polyphenol removal methods on the AH activity of L. latisiliquum acetone-water extracts when tested against Haemonchus contortus. The results showed that the extraction of oven-dried (OD) leaves of L. latisiliquum yielded a CT-free extract with high AH activity. However, polyphenol-free fractions showed similar or lower AH activity levels as of those original OD extract. HPLC analysis confirmed that common polyphenolic metabolites are not responsible for the AH activity of L. latisiliquum.     

Heat flow,heat capacity and thermal resistance of localized surfaces of the human body using a new calorimetric sensor

Journal of Thermal Analysis and Calorimetry - A non-invasive sensor equipped with a programmable thermostat has been developed to assess in vivo the heat flow transmitted by conduction from human...