(R)-Baclofen [(R)-4-amino-3-(4-chlorophenyl)butanoic acid]

This article provides the first single-crystal XRD-based structure of enantiopure (R)-baclofen (form C), C10H12ClNO2, without any co-crystallized substances. In the enantiopure title compound, the molecules arrange themselves in an orthorhombic crystal structure (space group P212121). In the crystal, strong hydrogen bonds and C—H ... Cl bonds interconnect the zwitterionic molecules.

Expanding the Known Structure Space for RNA Binding: A Test of 2,5-Diketopiperazine

As the importance of RNA as a therapeutic target has become increasingly recognized, the need for new chemotypes able to bind RNA has grown in significance. We hypothesized that diketopiperazines...

Исследование магнитных свойств ферроборатов неодима и самария методом спектроскопического эрбиевого зонда

Iron borates NdFe3(BO3)4 and SmFe3(BO3)4 activated with 1% erbium, with a huntite structure (space symmetry group R32) were investigated by the method of erbium spectroscopic probe. From an analysis of the temperature dependence of the transmission spectra in the region of the 4I15/2→4I13/2 transition in the Er3+ ion, it was found that both studied compounds order antiferromagnetically at TN ≈ 33 K into an easy-plane magnetic structure. No other phase transitions were found.

The solid solution TbNiIn1−x Ga x

Phase formation in the solid solution TbNiIn1−x Ga x at 873 K was investigated in the full concentration range by means of powder X-ray diffraction and EDX analysis. The samples were synthesized by arc-melting of the pure metals with subsequent annealing at 873 K for one month. The influence of the substitution of indium by gallium on the type of structure and solubility was studied. The solubility ranges have been determined and changes of the unit cell parameters were calculated on the basis of powder X-ray diffraction data: TbNiIn1–0.4Ga0–0.6 (ZrNiAl-type structure, space group P 6 ‾ 2 m $P‾{6}2m$ , a = 0.74461(8)–0.72711(17) and c = 0.37976(5)–0.37469(8) nm); TbNiIn0.2–0Ga0.8–1.0 (TiNiSi-type structure, space group Pnma, а = 0.68950(11)–0.68830(12), b = 0.43053(9)–0.42974(6), с = 0.74186(10)–0.73486(13) nm). The crystal structures of TbNiGa (TiNiSi type, Pnma, a = 0.69140(5), b = 0.43047(7), c = 0.73553(8) nm, wR2=0.0414, 525 F 2 values, 21 variables), TbNiIn0.83(1)Ga0.17(1) (ZrNiAl type, P 6 ‾ 2 m $P‾{6}2m$ , a = 0.74043(6), c = 0.37789(3) nm, wR2 = 0.0293, 322 F 2 values, 16 variables) and TbNiIn0.12(2)Ga0.88(2) (TiNiSi type, Pnma, a = 0.69124(6), b = 0.43134(9), c = 0.74232(11) nm, wR2 = 0.0495, 516 F 2 values, 21 variables) have been determined. The characteristics of the solid solutions and the variations of the unit cell parameters are briefly discussed.

Tm4IrIn and Lu4PtIn – In4 tetrahedra embedded in RE 22 polyhedra

The rare earth-rich indides Tm4IrIn and Lu4PtIn were synthesized by reaction of the elements in sealed tantalum ampules in an induction furnace. Tm4IrIn (a = 1340.77(4) pm) and Lu4PtIn (a = 1338.0(1) pm) crystallize with the Gd4RhIn-type structure, space group F 4 ‾ 3 m $F‾{4}3m$ . The Lu4PtIn structure was refined from single crystal X-ray diffractometer data: wR = 0.0524, 517 F 2 values and 20 variables. The striking crystal chemical motif is the fcc packing of In4 tetrahedra with 318 pm In–In. The Lu4PtIn structure is closely related to the structures of Lu13Ni6In, Lu14Pd3In3 and Lu20Ir5In3 which all show icosahedral indium coordination and different condensation patterns that build up the indium substructure that consists of a dumbbell in Lu14Pd3In3 and a triangle in Lu20Ir5In3. The results of magnetic susceptibility measurements indicate Curie-Weiss paramagnetism for Tm4IrIn (7.76(1) µB per thulium atom) without magnetic ordering down to 2.5 K. Lu4PtIn is Pauli-paramagnetic.

A novel user review-based contextual recommender system

Recommendation systems are shrewd applications for knowledge mining that profoundly handle the problem of data overload. Various literature explores different philosophies to create ideas and recommends different strategies according to the needs of customers. Most of the work in the suggested structure space focuses on extending the accuracy of the recommendation by using a few possible methods where the principle purpose remains to improve the accuracy of suggestions while avoiding other plan objectives, such as the particular situation of a client. By using appropriate customer rating data, the biggest test for a suggested system is to generate substantial proposals. A setting is an enormous concept that can think of numerous points of view: for example, the community of friends of a client, time, mindset, environment, organization, type of day, classification of an item, description of the object, place, and language. The rating behavior of customers typically varies in different environments. We have proposed a new review-based contextual recommender (RBCR) system application from this line of analysis, in particular a novel recommender system, which is an adaptable, quick, and accurate piece planning framework that perceives the significance of setting and fuses the logical data using piece stunt while making expectations. We have contrasted our suggested calculation with pre- and post-sifting methods as they have been the most common methodologies in writing to illuminate the issue of setting conscious suggestion. Our studies show that considering the logical data, the display of a system will increase and provide better, appropriate and important results on various evaluation measurements.

PbCN2 – an elucidation of its modifications and morphologies

Concerning the crystal structure of PbCN2 there exist two different descriptions in the literature, one based on the non-centrosymmetric structure, space group Pna21, another one on the centrosymmetric one in space group Pnma. To elucidate the conditions for their appearance, comprehensive preparative and structural investigations have been conducted which proved the existence of two distinct modifications of PbCN2. A detailed comparison of the two phases is provided. The growth conditions and crystallization processes of the two PbCN2 structures are reported with focus on the influence of the pH value on the products. Depending on the growth conditions several different morphologies arise, namely PbCN2 in needle-shaped and platelet-shaped crystals, as well as pompon-shaped and lance-shaped crystals.

Evidence for the Emergence of β-Trefoils by ‘Peptide Budding’ from an IgG-like β-Sandwich

As sequence and structure comparison algorithms gain sensitivity, the intrinsic interconnectedness of the protein universe has become increasingly apparent. Despite this general trend, β-trefoils have emerged as an uncommon counterexample: They are an isolated protein lineage for which few, if any, sequence or structure associations to other lineages have been identified. If β-trefoils are, in fact, remote islands in sequence-structure space, it implies that the oligomerizing peptide that founded the β-trefoil lineage itself arose de novo. To better understand β-trefoil evolution, and to probe the limits of fragment sharing across the protein universe, we identified both ‘β-trefoil bridging themes’ (evolutionarily-related sequence segments) and ‘β-trefoil-like motifs’ (structure motifs with a hallmark feature of the β-trefoil architecture) in multiple, ostensibly unrelated, protein lineages. The success of the present approach stems, in part, from considering β-trefoil sequence segments or structure motifs rather than the β-trefoil architecture as a whole, as has been done previously. The newly uncovered inter-lineage connections presented here suggest a novel hypothesis about the origins of the β-trefoil fold itself – namely, that it is a derived fold formed by ‘budding’ from an Immunoglobulin-like β-sandwich protein. These results demonstrate how the emergence of a folded domain from a peptide need not be a signature of antiquity and underpin an emerging truth: few protein lineages escape nature’s sewing table.

Crystal structure of mechanochemically prepared Ag2FeGeS4

Ag2FeGeS4 was synthesized as a phase-pure and highly crystalline product by mechanochemical milling from the binary sulfides and iron metal, followed by annealing in H2S atmosphere. The structure evaluation was carried out using X-ray powder diffraction with subsequent Rietveld refinements. As Fe and Ge atoms are not distinguishable using conventional X-ray methods, the chalcopyrite-type structure (space group I 4 ‾ 2 d $I‾{4}2d$ ), exhibiting a statistical distribution of Fe and Ge on Wyckoff position 4b, was considered. However, quantum-chemical calculations at hybrid density-functional level indicate that mechanochemically prepared Ag2FeGeS4 crystallizes in the kesterite-type structure (space group I 4 ‾ $I‾{4}$ ) where the cations are arranged in an ordered way. Ag2FeGeS4 is a further example of a mechanochemically prepared compound differing structurally from the commonly known polymorph exhibiting the stannite type (solid-state route).