Effects of pressurized hot water extraction on the nanoscale structure of birch sawdust

Pressurized hot water extraction with a flow-through system was used to extract hemicelluloses and lignin from birch sawdust. The structure of the extraction residue was studied on various levels. Molecular mass distributions were determined with gel permeation chromatography and the crystal structure of cellulose was characterized using wide-angle X-ray scattering (WAXS). Information on the short-range order of cellulose microfibrils and on the nanoscale pore structure was obtained with small-angle X-ray scattering (SAXS), and the micrometre scale cellular morphology was imaged with X-ray microtomography. The pressurized hot water treatment was observed to increase the lateral width of cellulose crystallites, determined with WAXS, whereas a possible small decrease in the crystallinity of cellulose compared to native wood was detected. The molecular mass of cellulose remained at a relatively high level. According to the SAXS results, a tighter lateral association of cellulose microfibrils was observed in the extracted samples, which possibly led to opening of pores between bundles of microfibrils, as indicated by an increased specific surface area. A reduction in the thickness of the fibre cell walls was evidenced by X-ray microtomography.     

{2,2′‐[(R,R)‐Cyclo­hexane‐1,2‐diyl­bis(nitrilo­methyl­idyne)]­bis[6‐tert‐butyl‐4‐(tri­phenyl­phosphonio­methyl)­phenol­ato]‐O,N,N′,O′}copper(II) dichloride hexakis­(deutero­chloro­form) solvate

The title compound, [Cu(C₆₆H₆₈N₂O₂P₂)]Cl₂·6CDCl₃, consists of complex cations, chloride ions and deutero­chloro­form solvate mol­ecules. The complex cation crystallizes in two different conformations. In both cases, Cu^II ions lie on twofold axes and the geometry around them is slightly distorted square planar. The dihedral angles between the N/Cu/N and O/Cu/O planes are 5.6 (9) and 3.9 (10)° for mol­ecules A and B, respectively.     

Comprehensive two-dimensional liquid chromatography coupled with mass spectrometry

In this review, instrumental aspects of comprehensive two-dimensional liquid chromatography coupled with mass spectrometry are presented. The milestones of LC×LC are briefly summarized. Instrument configuration, selection of experimental conditions, the different interfaces used in the system and the current applications of LC×LC–MS systems are described.     

Synthesis of novel (1-alkanoyloxy-4-alkanoylaminobutylidene)-1,1-bisphosphonic acid derivatives

A novel strategy for the synthesis of (1-alkanoyloxy-4-alkanoylaminobutylidene)-1,1-bisphosphonic acid derivatives (1a-d) via (1-hydroxy-4-alkanoylaminobutylidene)-1,1-bisphosphonic acid derivatives (2a-d), starting from alendronate has been developed with reasonable 51-77% overall yields. Intermediate products, (1-hydroxy-4-alkanoylaminobutylidene)-1,1-bisphosphonic acid derivatives (2a-d), were prepared in water with reasonable to high yields (52-94%).     

A UV resonance Raman (UVRR) spectroscopic study on the extractable compounds in Scots pine (Pinus sylvestris) wood. Part II. Hydrophilic compounds

Hydrophilic extracts of Scots pine (Pinus sylvestris) heartwood and sapwood and a solid Scots pine knotwood sample were studied by UV resonance Raman spectroscopy (UVRRS). In addition, UVRR spectra of two hydrophilic model compounds (pinosylvin and chrysin) were analysed. UV Raman spectra were collected using 244 and 257 nm excitation wavelengths. The chemical composition of the acetone:water (95:5 v/v) extracts were also determined by gas chromatography. The aromatic and oleophilic structures of pinosylvin and chrysin showed three intense resonance enhanced bands in the spectral region of 1649-1548 cm(-1). Pinosylvin showed also a relatively intense band in the aromatic substitution region at 996 cm(-1). The spectra of the heartwood acetone:water extract showed many bands typical of pinosylvin. In addition, the extract included bands distinctive for resin and fatty acids. The sapwood acetone:water extract showed bands due to oleophilic structures at 1655-1650 cm(-1). The extract probably also contained oligomeric lignans because the UVRR spectra were in parts similar to that of guaiacyl lignin. The characteristic band of pinosylvin (996 cm(-1)) was detected in the UVRR spectrum of the resin rich knotwood. In addition, several other bands typical for wood resin were observed, which indicated that the wood resin in the knotwood was resonance enhanced even more than lignin.     

A UV resonance Raman (UVRR) spectroscopic study on the extractable compounds of Scots pine (Pinus sylvestris) wood. Part I: lipophilic compounds

The wood resin in Scots pine (Pinus sylvestris) stemwood and branch wood were studied using UV resonance Raman (UVRR) spectroscopy. UVRR spectra of the sapwood and heartwood hexane extracts, solid wood samples and model compounds (six resin acids, three fatty acids, a fatty acid ester, sitosterol and sitosterol acetate) were collected using excitation wavelengths of 229, 244 and 257 nm. In addition, visible Raman spectra of the fatty and resin acids were recorded. Resin compositions of heartwood and sapwood hexane extracts were determined using gas chromatography. Raman signals of both conjugated and isolated double bonds of all the model compounds were resonance enhanced by UV excitation. The oleophilic structures showed strong bands in the region of 1660-1630 cm(-1). Distinct structures were enhanced depending on the excitation wavelength. The UVRR spectra of the hexane extracts showed characteristic bands for resin and fatty acids. It was possible to identify certain resin acids from the spectra. UV Raman spectra collected from the solid wood samples containing wood resin showed a band at approximately 1650 cm(-1) due to unsaturated resin components. The Raman signals from extractives in the resin rich branch wood sample gave even more strongly enhanced signals than the aromatic lignin.     

Novel Bioreversible Prodrugs of Clodronate

Abstract

Clodronate (1) belongs to family of bisphosphonates which are used to inhibit mineralization of soft tissues as well as bone formation and resorption disorders.[I] The clinical use of bisphosphonates is limited due to their poor bióvailability which is mostly attributed to their hydrophilic structure. More lipophilic molecules are obtained if some or all of the anionic sites are converted to covalent bonds. We herein report a new prodrug serie for clodronate: the anhydrides 2 and 3. Previously we have reported that the simple alkyl esters 4 do not release clodronate via chemical or enzymatic hydrolysis.[2] The prepared new derivatives are stable in water (pH 5–7.5) but clodronate isrelased rapidly with enzymatic hydrolysis.     

Comparison of separation power of ultra performance liquid chromatography and comprehensive two-dimensional liquid chromatography in the separation of phenolic compounds in beverages

In this study, 1-D and 2-D liquid chromatographic systems, namely, conventional HPLC, UPLC, HPLC x HPLC and HPLC x UPLC systems were developed and evaluated for the separation of phenolic acids in wine and juices. In the LC x LC studies, the first dimension separation was based on RPLC and the second dimension was performed with ion-pair chromatography. Three different columns, namely two short columns packed with either 2.5 or 1.7 microm particles and a monolithic column, were tested for the fast second dimension separation. The best results were obtained when the monolithic column was applied for the second dimension separation. The peak capacities for comprehensive 2-D systems varied from 330 to 616.     

Effect of wet spinning parameters on the properties of novel cellulosic fibres

Novel cellulose fibres (Biocelsol) were spun by traditional wet spinning technique from the alkaline solution prepared by dissolving enzyme treated pulp directly into aqueous sodium zincate (ZnO/NaOH). The spinning dope contained 6 wt.% of cellulose, 7.8 wt.% of sodium hydroxide (NaOH) and 0.84 wt.% of zinc oxide (ZnO). The fibres were spun into 5% and 15% sulphuric acid (H₂SO₄) baths containing 10% sodium sulphate (Na₂SO₄). The highest fibre tenacity obtained was 1.8 cNdtex⁻¹ with elongation of 15% and titre of 1.4 dtex. Average molecular weights and shape of molecular weight distribution curves of the celluloses from the novel wet spun cellulosic fibre and from the commercial viscose fibre were close to each other.     

Comparison of virtual high-throughput screening methods for the identification of phosphodiesterase-5 inhibitors

Reliable and effective virtual high-throughput screening (vHTS) methods are desperately needed to minimize the expenses involved in drug discovery projects. Here, we present an improvement to the negative image-based (NIB) screening: the shape, the electrostatics, and the solvation state of the target protein's ligand-binding site are included into the vHTS. Additionally, the initial vHTS results are postprocessed with molecular mechanics/generalized Born surface area (MMGBSA) calculations to estimate the favorability of ligand-protein interactions. The results show that docking produces very good early enrichment for phosphodiesterase-5 (PDE-5); however, in general, the NIB and the ligand-based screening performed better with or without the added electrostatics. Furthermore, the postprocessing of the NIB screening results using MMGBSA calculations improved the early enrichment for the PDE-5 considerably, thus, making hit discovery affordable.