Thermal Conversion of Guanylurea Dicyanamide into Graphitic Carbon Nitride via Prototype CNx Precursors

Guanylurea dicyanamide, [(H2N)C(-O)NHC(NH2)2][N(CN)2], has been synthesized by ion exchange reaction in aqueous solution and structurally characterized by single-crystal X-ray diffraction (C2/c, a = 2249.0(5) pm, b = 483.9(1) pm, c = 1382.4(3) pm, β = 99.49(3)°, V = 1483.8(5) × 106 pm3, T = 130 K). The thermal behavior of the molecular salt has been studied by thermal analysis, temperature-programmed X-ray powder diffraction, FTIR spectroscopy, and mass spectrometry between room temperature and 823 K. The results were interpreted on a molecular level in terms of a sequence of thermally induced addition, cyclization, and elimination reactions. As a consequence, melamine (2,4,6-triamino-1,3,5-triazine) is formed with concomitant loss of HNCO. Further condensation of melamine yields the prototypic CNx precursor melem (2,6,10-triamino-s-heptazine, C6N7(NH2)3), which alongside varying amounts of directly formed CNxHy material transforms into layered CNxHy phases without significant integration of oxygen into the core framework owing to the evaporation of HNCO. Thus, further evidence can be added to melamine and its condensation product melem acting as “key intermediates” in the synthetic pathway toward graphitic CNxHy materials, whose exact constitution is still a point at issue. Due to the characteristic formation process and hydrogen content a close relationship with the polymer melon is evident. In particular, the thermal transformation of guanylurea dicyanamide clearly demonstrates that the formation of volatile compounds such as HNCO during thermal decomposition may render a large variety of previously not considered molecular compounds suitable CNx precursors despite the presence of oxygen in the starting material

Phenotypic indicators to identify methionine rich European grain legumes and the correlation of grain methionine contents with the sulphur supply

Home grown legumes are a valuable protein source for pure on-farm diets for livestock in organic farming. Whereas protein of Glycine max naturally has higher contents of methionine nand also lysine typical European grain legumes (Pisum sativum L., Vicia faba L., Lupinus angustifolius L.) used in organic farms as component of animal food are relatively low in those amino acids

Cyclometalated complexes of platinum and gold with biological properties: state-of-the-art and future perspectives

The inherent problems accompanying chemotherapy necessitate the development of new anticancer approaches. The development of compounds that can disrupt cancerous cellular machinery by novel mechanisms, via interactions with proteins and non-canonical DNA structures (e.g. G-quadruplexes), as well as by alteration of the intracellular redox balance, is nowadays focus of intense research. In this context organometallic compounds of the noble metals Pt and Au have become prominent experimental therapeutic agents. This review provides an overview of the Pt(II) and Au(III) cyclometalated compounds with a chelating ring containing a strong C-M σ-bond to improve the stability of the compounds with respect to ligand exchange reactions and biological reduction. Furthermore, these properties can be easily tuned by modification of either the anionic cyclometalated or the ancillary ligands. Special focus has been set to C^N, C^N^C, C^N^N and C^N^S platinum(II) and gold(III) pincer complexes regarding their synthesis and biological modes of action as anticancer agents. Methods: A structured search of both chemical and medicinal databases for peer-reviewed research literature has been conducted. The quality of retrieved papers was appraised using standard tools. The synthesis as well as the chemical and biological properties of the described compounds were carefully reviewed and described. The findings were outlined using a conceptual framework. Results: In this review we included 155 papers, the majority originating from high-impact papers on the synthesis and biological modes of platinum(II) and gold(III) compounds. Among them, 17 papers were highlighted to give an introduction to the use of Pt and Au compounds with medicinal properties, mainly focussing on coordination compounds. The synthesis and medicinal properties of organometallic compounds of various metals (such as Fe, Ru, Ti) were outlined in 51 papers. These compounds included metallocenes, metallo-arenes, metallo-carbonyls, metallo-carbenes (e.g. Nheterocyclic carbenes), and alkynyl complexes. The C^N, C^N^C, C^N^N and C^N^S pincer complexes of platinum(II) (46 papers) and gold(III) (44 papers) were discussed concerning their synthesis, stability and advantages to develop therapeutic compounds. We strove to show the consistent development of C^N, C^N^C, C^N^N and C^N^S platinum(II) and gold(III) pincer complexes regarding their synthesis and biological modes from the early beginnings to the most recent findings. Conclusion: This review supplies a profound overview of the development of organometallic compounds for medicinal purposes, setting special focus to the synthesis and stability of C^N, C^N^C, C^N^N and C^N^S pincer complexes of platinum(II) and gold(III) and their use as anticancer agents

Exploring the C^N^C theme: Synthesis and biological properties of tridentate cyclometalated gold(III) complexes

A family of cyclometalated Au(III) complexes featuring a tridentate CNC scaffold has been synthesized and characterized. Microwave assisted synthesis of the ligands has also been exploited and optimized. The biological properties of the thus formed compounds have been studied in cancer cells and demonstrate generally moderate antiproliferative effects. Initial mechanistic insights have also been gained on the gold complex [Au(CNC)(GluS)] (3), and support the idea that the thioredoxin system may be a target for this family of compounds together with other relevant intracellular thiol-containing molecules. (C) 2017 Elsevier Ltd. All rights reserved

csal1 Is Controlled by a Combination of FGF and Wnt Signals in Developing Limb Buds

While some of the signaling molecules that govern establishment of the limb axis have been characterized, little is known about the downstream effector genes that interpret these signals. In Drosophila, the spalt gene is involved in cell fate determination and pattern formation in different tissues. We have cloned a chick homologue of Drosophila spalt, which we have termed csal1, and this study focuses on the regulation of csal1 expression in the limb bud. csal1 is expressed in limb buds from HH 17 to 26, in both the apical ectodermal ridge and the distal mesenchyme. Signals from the apical ridge are essential for csal1 expression, while the dorsal ectoderm is required for csal1 expression at a distance from the ridge. Our data indicate that both FGF and Wnt signals are required for the regulation of csal1 expression in the limb. Mutations in the human homologue of csal1, termed Hsal1/SALL1, result in a condition known as Townes–Brocks syndrome (TBS), which is characterized by preaxial polydactyly. The developmental expression of csal1 together with the digit phenotype in TBS patients suggests that csal1 may play a role in some aspects of distal patterning

LIGHTSITE II Randomized Multicenter Trial: Evaluation of Multiwavelength Photobiomodulation in Non-exudative Age-Related Macular Degeneration.

INTRODUCTION Photobiomodulation (PBM) represents a potential treatment for non-exudative age-related macular degeneration (AMD). PBM uses wavelengths of light to target components of the mitochondrial respiratory chain to improve cellular bioenergetic outputs. The aim of this study was to further investigate the effects of PBM on clinical, quality of life (QoL) and anatomical outcomes in subjects with intermediate stage non-exudative AMD. METHODS The multicenter LIGHTSITE II study was a randomized clinical trial evaluating safety and efficacy of PBM in intermediate non-exudative AMD. The LumiThera Valeda® Light Delivery System delivered multiwavelength PBM (590, 660 and 850 nm) or sham treatment 3 × per week over 3-4 weeks (9 treatments per series) with repeated treatments at baseline (BL), 4 and 8 months. Subjects were enrolled with 20/32 to 20/100 best-corrected visual acuity (BCVA) and no central geographic atrophy (GA) within the central fovea (500 μm). RESULTS LIGHTSITE II enrolled 44 non-exudative AMD subjects (53 eyes). PBM-treated eyes showed statistically significant improvement in BCVA at 9 months (n = 32 eyes, p = 0.02) with a 4-letter gain in the PBM-treated group versus a 0.5-letter gain in the sham-treated group (ns, p < 0.1) for patients that received all 27 PBM treatments (n = 29 eyes). Approximately 35.3% of PBM-treated eyes showed ≥ 5-letter improvement at 9 months. Macular drusen volume was not increased over time in the PBM-treated group but did show increases in the sham-treated group. While PBM and sham groups both showed GA lesion growth in the trial period, there was 20% less growth in the PBM group over 10 months, suggesting potential disease-modifying effects. No safety concerns or signs of phototoxicity were observed. CONCLUSION These results confirm previous clinical testing of multiwavelength PBM and support treatment with Valeda as a novel therapy with a unique mechanism of action as a potential treatment for non-exudative AMD. TRIAL REGISTRATION Clinicaltrial.Gov Registration Identifier: NCT03878420

Oxidative modification of low-density lipoproteins and the outcome of renal allografts at 11/2 years

Oxidative modification of low-density lipoproteins and the outcome of renal allografts at 11/2 years.BackgroundPrevious studies reported a significant association between hyperlipidemia of the recipient and chronic allograft nephropathy (CAN). However, the nature and the pathogenic mechanism of circulating lipid abnormalities in CAN remain unclear.MethodsIn a prospective study of 50 consecutive adult recipients of a cadaveric renal allograft, we investigated the impact of lipid abnormalities on the outcome of the graft at 11/2 years. Besides morphometric analysis of implantation and protocol biopsies, clinical and biochemical variables were studied at three-month intervals. Plasma concentrations of oxidized low-density lipoprotein (OxLDL) were determined by means of enzyme-linked immunosorbent assay. Immunohistochemical staining for OxLDL and macrophages was performed on paired renal biopsies. Study end points were the fractional interstitial volume and the 24-hour creatinine clearance at 11/2 years.ResultsHigh-density lipoprotein (HDL) cholesterol of the recipient ≤47 mg/dL was a risk factor for the functional (RR = 1.56; 95% CI, 0.978 to 2.497) and the morphological (RR = 2.75; 95% CI, 1.075 to 7.037) outcome of the graft, mainly in patients without acute rejection (RR = 2.03; 95% CI, 1.13 to 3.65, and RR = 4.67; 95% CI, 1.172 to 18.582, respectively). Interstitial accumulation of OxLDL was inversely associated with HDL cholesterol (R = -0.476, P = 0.019), and was associated with a higher density of tubulointerstitial macrophages (R = 0.656, P = 0.001) and a higher fractional interstitial volume at 11/2 years (P = 0.049).ConclusionDecreased HDL cholesterol levels of the recipient adversely affect the outcome of renal allografts through the accumulation of OxLDL in the renal interstitium of the graft. Interstitial accumulation of OxLDL was associated with the presence of macrophages and the development of interstitial fibrosis