CODATA Recommended Values of the Fundamental Physical Constants: 2018.

We report the 2018 self-consistent values of constants and conversion factors of physics and chemistry recommended by the Committee on Data of the International Science Council. The recommended values can also be found at physics.nist.

CODATA recommended values of the fundamental physical constants: 2018.

We report the 2018 self-consistent values of constants and conversion factors of physics and chemistry recommended by the Committee on Data of the International Science Council (CODATA). The recommended values can also be found at physics.nist.

Clinical outcomes of endovascular treatment of TASC-II C and D femoropopliteal lesions with the Viabahn endoprosthesis.

Objectives: The objective of this study was to evaluate clinical outcomes and patency rates using the Viabahn endoprosthesis in complex (TASC-II C and D) femoropopliteal lesions.

Background: Traditional treatment of symptomatic TASC-II C and D femoropopliteal lesions has mainly centered on open surgical options in patients deemed appropriate candidates. Endovascular treatment of these lesions with balloon angioplasty has been historically hampered by aggressive restenosis and relatively early clinical failure.

C5-Alkyl-2-methylurea-Substituted Pyridines as a New Class of Glucokinase Activators.

Glucokinase (GK) activators represent a class of type 2 diabetes therapeutics actively pursued due to the central role that GK plays in regulating glucose homeostasis. Herein we report a novel C5-alkyl-2-methylurea-substituted pyridine series of GK activators derived from our previously reported thiazolylamino pyridine series. Our efforts in optimizing potency, enzyme kinetic properties, and metabolic stability led to the identification of compound 26 (AM-9514).

Discovery of Disubstituted Imidazo[4,5-b]pyridines and Purines as Potent TrkA Inhibitors.

Trk receptor tyrosine kinases have been implicated in cancer and pain. A crystal structure of TrkA with AZ-23 (1a) was obtained, and scaffold hopping resulted in two 5/6-bicyclic series comprising either imidazo[4,5-b]pyridines or purines. Further optimization of these two fusion series led to compounds with subnanomolar potencies against TrkA kinase in cellular assays.

Single-agent inhibition of Chk1 is antiproliferative in human cancer cell lines in vitro and inhibits tumor xenograft growth in vivo.

Chk1 is a serine/threonine kinase that plays several important roles in the cellular response to genotoxic stress. Since many current standard-of-care therapies for human cancer directly damage DNA or inhibit DNA synthesis, there is interest in using small molecule inhibitors of Chk1 to potentiate their clinical activity. Additionally, Chk1 is known to be critically involved in cell cycle progression of unperturbed cells.

Adapting the International System of Units to the twenty-first century.

We review the proposal of the International Committee for Weights and Measures (Comité International des Poids et Mesures, CIPM), currently being considered by the General Conference on Weights and Measures (Conférences Générales des Poids et Mesures, CGPM), to revise the International System of Units (Le Système International d'Unitès, SI). The proposal includes new definitions for four of the seven base units of the SI, and a new form of words to present the definitions of all the units. The objective of the proposed changes is to adopt definitions referenced to constants of nature, taken in the widest sense, so that the definitions may be based on what are believed to be true invariants.

Identification of 4-aminopyrazolylpyrimidines as potent inhibitors of Trk kinases.

The design, synthesis and biological evaluation of a series of 4-aminopyrazolylpyrimidines as potent Trk kinase inhibitors is reported. High-throughput screening identified a promising hit in the 4-aminopyrazolylpyrimidine chemotype. Initial optimization of the series led to more potent Trk inhibitors.

Fundamental constants and tests of theory in Rydberg states of hydrogenlike ions.

A comparison of precision frequency measurements to quantum electrodynamics (QED) predictions for Rydberg states of hydrogenlike ions can yield information on values of fundamental constants and test theory. With the results of a calculation of a key QED contribution reported here, the uncertainty in the theory of the energy levels is reduced to a level where such a comparison can yield an improved value of the Rydberg constant.

Straight-edge diffraction of Planck radiation.

The irradiance diffraction profile of a straight edge is given as a Taylor series in powers of the distance from the geometrical shadow boundary to any point in the profile for monochromatic radiation. The coefficients of the series, which are obtained as simple analytic expressions, are proportional to the real part of a complex number whose phase cycles through a complete period every eight terms in the series. Integration of this series over a Planck distribution of radiation yields the power series for the Planck profile; this derived series has a finite radius of convergence.

Precise calculation of transition frequencies of hydrogen and deuterium based on a least-squares analysis.

We combine a limited number of accurately measured transition frequencies in hydrogen and deuterium, recent quantum electrodynamics (QED) calculations, and, as an essential additional ingredient, a generalized least-squares analysis, to obtain precise and optimal predictions for hydrogen and deuterium transition frequencies. Some of the predicted transition frequencies have relative uncertainties more than an order of magnitude smaller than that of the g factor of the electron, which was previously the most accurate prediction of QED.

The fundamental constants and theory.

The Committee on Data for Science and Technology has recently recommended a new self-consistent set of values of basic constants and conversion factors of physics and chemistry. These values are based on a least-squares analysis that takes into account all of the latest relevant experimental and theoretical information in a consistent framework. Theory plays a role, because the experimental data are compared to the corresponding theoretical predictions which are functions of the fundamental constants.

Asymptotic properties of self-energy coefficients.

We investigate the asymptotic properties of higher-order binding corrections to the one-loop self-energy of excited states in atomic hydrogen. We evaluate the historically problematic A60 coefficient for all P states with principal quantum numbers n View Article and Find Full Text PDF

Total synthesis of (+)-phomactin a using a B-alkyl Suzuki macrocyclization.

A total synthesis of (+)-phomactin A is described using a B-alkyl Suzuki macrocyclization to incorporate the isolated trisubstituted olefin. This macrocyclization was accomplished with the sensitive hydrated furan ring in place. (R)-(+)-pulegone was used to establish the highly substituted cyclohexene core of the molecule.

Convergent enantioselective synthesis of the tricyclic core of phomactin A.

[reaction: see text] The tricyclic core of phomactin A was synthesized from 6,6-dimethyl-2-cyclohexen-1-one. Key reactions include the addition of a cyclohexenyllithium reagent to an epoxyaldehyde and a regioselective intramolecular epoxide opening to install the oxadecalin core.