The Hydrogen-Bond Continuum in the Salt/Cocrystal Systems of Quinoline and Chloro-Nitrobenzoic Acids.

This study investigates the hydrogen-bond geometry in six two-component solid systems composed of quinoline and chloro-nitrobenzoic acids. New X-ray diffraction studies were conducted using both the conventional independent-atom model and the more recent Hirshfeld atom-refinement method, with the latter providing precise hydrogen-atom positions. The systems can be divided into salts (the hydrogen atom transferred to the quinoline nitrogen), cocrystals (the hydrogen atom retained by the acid), and intermediate structures.

Disadvantage of the FDM method for printing protective masks against COVID-19 and solution.

Outages in the supply of basic medical supplies and protective equipment have led to efforts to replace them. The team of BUT employees and students has developed a protective half mask that can also be printed on a standard 3D printer without the use of special materials. The original half mask is intended as an improvised protection that can be easily printed on standard 3D printers with FDM technology.

Erbium ion implantation into diamond - measurement and modelling of the crystal structure.

Diamond is proposed as an extraordinary material usable in interdisciplinary fields, especially in optics and photonics. In this contribution we focus on the doping of diamond with erbium as an optically active centre. In the theoretical part of the study based on DFT simulations we have developed two Er-doped diamond structural models with 0 to 4 carbon vacancies in the vicinity of the Er atom and performed geometry optimizations by the calculation of cohesive energies and defect formation energies.

Erratum: Capecitabine from X-ray powder synchrotron data. Corrigendum.

[This corrects the article DOI: 10.1107/S1600536809017905.].

10-Methyl-isoalloxazine 5-oxide from synchrotron powder diffraction data.

THE TITLE COMPOUND [SYSTEMATIC NAME: 10-methyl-benzo[g]pteridine-2,4(3H,10H)-dione 5-oxide], C(11)H(8)N(4)O(3), consists of a large rigid isoalloxazine group which is approximately planar (r.m.s.

Alaptide from synchrotron powder diffraction data.

THE TITLE COMPOUND [SYSTEMATIC NAME: (8S)-8-methyl-6,9-diaza-spiro-[4.5]decane-7,10-dione], C(9)H(14)N(2)O(2), consists of two connected rings, viz. a piperazine-2,5-dione (DKP) ring and a five-membered ring.

Capecitabine from X-ray powder synchrotron data.

In the title compound [systematic name 5-de-oxy-5-fluoro-N-(pent-yloxycarbon-yl)cytidine], C(15)H(22)FN(3)O(6), the pentyl chain is disordered over two positions with refined occupancies of 0.53 (5) and 0.47 (5).

Methyl-ergometrine maleate from synchrotron powder diffraction data.

The title compound {systematic name: 9,10-didehydro-N-[1-(hydroxy-meth-yl)prop-yl]-d-lysergamide maleate}, C(20)H(26)N(3)O(2) (+)·C(4)H(3)O(4) (-), contains a large rigid ergolene group. This group consists of an indole plane connected to a six-membered carbon ring adopting an envelope conformation and N-methyl-tetra-hydro-pyridine where the methyl group is in an equatorial position. In the crystal, inter-molecular N-H⋯O, O-H⋯N and O-H⋯O hydrogen bonds form an extensive three-dimensional hydrogen-bonding network, which holds the cations and anions together.

Three-dimensional reconstruction of anomalous chloroplasts in transgenic ipt tobacco.

Anomalies in the ultrastructure of chloroplasts, from transgenic ipt tobacco, overproducing endogenous cytokinins (CKs) were studied. Detailed analyses of CKs and their metabolites showed that Pssu-ipt tobacco contained enhanced contents of CKs both in leaves and in isolated chloroplasts. The role of CKs in the formation of anomalous structures is suggested.

Structural characterization of photosystem II complex from red alga Porphyridium cruentum retaining extrinsic subunits of the oxygen-evolving complex.

The structure of photosystem II (PSII) complex isolated from thylakoid membranes of the red alga Porphyridium cruentum was investigated using electron microscopy followed by single particle image analysis. The dimeric complexes observed contain all major PSII subunits (CP47, CP43, D1 and D2 proteins) as well as the extrinsic proteins (33 kDa, 12 kDa and the cytochrome c(550)) of the oxygen-evolving complex (OEC) of PSII, encoded by the psbO, psbU and psbV genes, respectively. The single particle analysis of the top-view projections revealed the PSII complex to have maximal dimensions of 22 x 15 nm.