Modulated Self-Assembly of Catalytically Active Metal–Organic Nanosheets Containing Zr6 Clusters and Dicarboxylate Ligands

Two-dimensional metal–organic nanosheets (MONs) have emerged as attractive alternatives to their three-dimensional metal–organic framework (MOF) counterparts for heterogeneous catalysis due to their greater external surface areas and higher accessibility of catalytically active sites. Zr MONs are particularly prized because of their chemical stability and high Lewis and Brønsted acidities of the Zr clusters. Herein, we show that careful control over modulated self-assembly and exfoliation conditions allows the isolation of the first example of a two-dimensional nanosheet wherein Zr6 clusters are linked by dicarboxylate ligands. The hxl topology MOF, termed GUF-14 (GUF = Glasgow University Framework), can be exfoliated into monolayer thickness hns topology MONs, and acid-induced removal of capping modulator units yields MONs with enhanced catalytic activity toward the formation of imines and the hydrolysis of an organophosphate nerve agent mimic. The discovery of GUF-14 serves as a valuable example of the undiscovered MOF/MON structural diversity extant in established metal–ligand systems that can be accessed by harnessing the power of modulated self-assembly protocols

Compositional analysis of the associations between 24-h movement behaviours and cardio-metabolic risk factors in overweight and obese adults with pre-diabetes from the PREVIEW study: cross-sectional baseline analysis

Background: Physical activity, sedentary time and sleep have been shown to be associated with cardio-metabolic health. However, these associations are typically studied in isolation or without accounting for the effect of all movement behaviours and the constrained nature of data that comprise a finite whole such as a 24 h day. The aim of this study was to examine the associations between the composition of daily movement behaviours (including sleep, sedentary time (ST), light intensity physical activity (LIPA) and moderate-to-vigorous activity (MVPA)) and cardio-metabolic health, in a cross-sectional analysis of adults with pre-diabetes. Further, we quantified the predicted differences following reallocation of time between behaviours. Methods: Accelerometers were used to quantify daily movement behaviours in 1462 adults from eight countries with a body mass index (BMI) ≥25 kg·m− 2 , impaired fasting glucose (IFG; 5.6–6.9 mmol·l − 1 ) and/or impaired glucose tolerance (IGT; 7.8–11.0 mmol•l − 1 2 h following oral glucose tolerance test, OGTT). Compositional isotemporal substitution was used to estimate the association of reallocating time between behaviours. Results: Replacing MVPA with any other behaviour around the mean composition was associated with a poorer cardio-metabolic risk profile. Conversely, when MVPA was increased, the relationships with cardiometabolic risk markers was favourable but with smaller predicted changes than when MVPA was replaced. Further, substituting ST with LIPA predicted improvements in cardio-metabolic risk markers, most notably insulin and HOMA-IR. Conclusions: This is the first study to use compositional analysis of the 24 h movement composition in adults with overweight/obesity and pre-diabetes. These findings build on previous literature that suggest replacing ST with LIPA may produce metabolic benefits that contribute to the prevention and management of type 2 diabetes. Furthermore, the asymmetry in the predicted change in risk markers following the reallocation of time to/from MVPA highlights the importance of maintaining existing levels of MVPA. Trial registration: ClinicalTrials.gov (NCT01777893)

Epigenetic regulation of fetal bone development and placental transfer of nutrients: progress for osteoporosis

Osteoporosis is a common age-related disorder and causes acute and long-term disability and economic cost. Many factors influence the accumulation of bone minerals, including heredity, diet, physical activity, gender, endocrine functions, and risk factors such as alcohol, drug abuse, some pharmacological drugs or cigarette smoking. The pathology of bone development during intrauterine life is a factor for osteoporosis. Moreover, the placental transfer of nutrients plays an important role in the building of bones of fetuses. The importance of maternal calcium intake and vitamin D status are highlighted in this review. Various environmental factors including nutrition state or maternal stress may affect the epigenetic state of a number of genes during fetal development of bones. Histone modifications as histone hypomethylation, histone hypermethylation, hypoacetylation, etc. are involved in chromatin remodeling, known to contribute to the epigenetic landscape of chromosomes, and play roles in both fetal bone development and osteoporosis. This review will give an overview of epigenetic modulation of bone development and placental transfer of nutrients. In addition, the data from animal and human studies support the role of epigenetic modulation of calcium and vitamin D in the pathogenesis of osteoporosis. We review the evidence suggesting that various genes are involved in regulation of osteoclast formation and differentiation by osteoblasts and stem cells. Epigenetic changes in growth factors as well as cytokines play a rol in fetal bone development. On balance, the data suggest that there is a link between epigenetic changes in placental transfer of nutrients, including calcium and vitamin D, abnormal intrauterine bone development and pathogenesis of osteoporosis

Механизми на неврорегенерация от стволови/прогениторни мозъчни клетки

Росица Данаилова Методиева; \ud Катедра по фармакология и токсикология; \ud Медицински факултет; \ud Медицински университет; \ud ул. „Здраве” № 2; \ud 1431 София; \ud tel. 02/9520539; 0884 750 591;\ud e-mail: [email protected]Резюме. Невронната регенерация от мозъчни стволови и от техни прогениторни клетки включва участието на различни ендогенни и екзогенни вещества и механизми. В обзора е описана ролята на растежните фактори, като FGG, VEGF, GDGF, BDNF, erythropoietin, G-CSF, както и на angiopoietin-1 (Angpo-1) и angiopoietin-2 (Angpo-2). Диференцирането на\ud неврони в различни зони на мозъка включва и участие на цитокини като TNF-алфа, IL-6, IL-1, адхезионни молекули и ензими. Епигенетичните механизми се отразяват на патогенезата на мозъчните заболявания, неврорегенерацията и фармакотерапията. Ролята на histone acetyltransferase\ud p300/CBP-associated factor в епигенетичното модулиране на неврорегенерация също е отразена в обзора. Новодиференцирани от нас хипоталамични бета-ендорфинови неврони от мозъчни стволови клетки са внедрени експериментално при мозъчни увреждания. Новостите в механизмите на неврорегенериране се прилагат при лечение на мозъчен инсулт, мозъчни и гръбначномозъчни травми и различни невронални заболявания. ***** Summary. Neuronal regeneration from neuronal stem cells (NSCs) and their progentitor cells in brain is important in the treatment of various diseases. The roles of different growth factors as the FGG, VEGF, GDGF, BDNF,angiopoietin-\ud 2 (Angpo-2) in mechanisms of neuronal regeneration from stem cells in\ud brain are illustrated in the present paper. In addition various cytokines as the\ud TNF-alpha, IL-6, IL-1, or adhesion molecules are involved in differentiation of\ud NSCs. Epigenetic mechanisms are discovered in pathogenesis and\ud pharmacotherapy of brain diseases as well as in neuronal regeneration. New\ud molecule, histone acetyltransferase p300/CBP-associated factor is involved in\ud epigenetic mechanisms of differentiation of brain cells from stem cells. The\ud data presented here suggest that various factors may have a role in the\ud mechanisms of brain tissue recovering and in the neuronal function after trauma, ischemia, etc. by activation of neuronal development from NSCs

Modulated self-assembly of hcp topology MOFs of Zr/Hf and the rxtended 4,4′-(Ethyne–1,2–diyl)dibenzoate linker

Careful control of synthetic conditions can enhance the structural diversity of metal-organic frameworks (MOFs) within individual metal-linker combinations. Herein, we show that hcp topology MOFs of both Zr(IV) and Hf(IV), linked by the extended (ethyne–1,2–diyl)dibenzoate linker, can be prepared by modulated self-assembly. The controlled addition of acetic acid and water to solvothermal syntheses is essential to generate these phase pure hcp topology materials, which are characterised experimentally and computationally. The central alkyne unit of the linker can be quantitatively brominated, but this results in partial degradation of the hcp phase, in contrast to the more stable fcu topology analogues. Nevertheless, the MOFs represent new members of the hcp topology isoreticular series showing high crystallinity and porosity, and demonstrate that new materials can be discovered in existing MOF phase spaces through judicious adjustment of key synthetic parameters