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Abstract: A series of mesoporous carbons with high loading of silica has been synthesized by acid-catalyzed polymerization of resorcinol and formaldehyde in the presence of tetraethyl orthosilicate (TEOS), colloidal silica (silica source) and poly(ethylene oxide)–poly(propylene oxide)–poly(ethylene oxide) triblock copolymer (soft template) followed by carbonization. This synthesis route can be considered as a combination of soft-templating and hard templating strategies. The resulting mesoporous silica–carbon composites contained spherical silica colloids in addition to uniformly distributed silica originated from TEOS. Dissolution of silica led to high surface area carbons, which in addition to the primary mesopores formed by thermal degradation of block copolymer template possessed spherical mesopores after dissolution of silica colloids and fine pores after removal of TEOS-generated silica species. This approach can be used to incorporate other inorganic nanoparticles into mesoporous carbons with extra microporosity created after dissolving TEOS-generated silica species. [Copyright &y& Elsevier]

Nitrogen adsorption studies have been employed to examine the structural properties of micro-/meso-porous carbons obtained by colloidal templating and post-synthesis KOH activation. These carbons were prepared by polymerizing phenol and formaldehyde in the pores of a colloidal silica template followed by carbonization, silica dissolution and post-synthesis KOH activation. Colloidal silica was used to create spherical mesopores, while KOH activation was performed to create additional microporosity and to enlarge the surface area of the resulting carbons. Nitrogen adsorption studies showed that a single impregnation of the colloidal silica template with phenolic resin precursors afforded carbons with relatively thin pore walls which did not withstand the post-synthesis KOH activation; however, a double impregnation generated mesoporous carbons with thicker pore walls. Activation of these latter carbons with KOH created micropores in the mesopore walls without significant deterioration of the mesopore structure. The resulting mesoporous carbons possessed high specific surface areas (ca. 800 m2/g) and large single-point pore volumes (ca. 1.8 cm3/g). The post-synthesis KOH activation enlarged the surface area up to 1500 m2/g, which was achieved via the creation of microporosity. Hence, the carbon obtained by double impregnation and activation exhibited a single-point pore volume of ca. 2 cm3/g with a relatively high microporosity which attained 17% of the total porosity. High-surface-area micro-/meso-porous carbons are attractive for adsorption, catalysis and energy-related applications such as capacitors and batteries. [ABSTRACT FROM AUTHOR]

Hepatoblastoma (HB) is the most common pediatric liver cancer. Although long-term survival of HB is generally favorable, it depends on clinical stage, tumor histology, and a variety of biochemical and molecular features. HB appears almost exclusively before the age of 3 years, is represented by seven histological subtypes, and is usually associated with highly heterogeneous somatic mutations in the catenin β1 (CTNNB1) gene, which encodes β-catenin, a Wnt ligand–responsive transcriptional co-factor. Numerous recurring β-catenin mutations, not previously documented in HB, have also been identified in various other pediatric and adult cancer types. Little is known about the underlying factors that determine the above HB features and behaviors or whether non-HB–associated β-catenin mutations are tumorigenic when expressed in hepatocytes. Here, we investigated the oncogenic properties of 14 different HB– and non-HB–associated β-catenin mutants encoded by Sleeping Beauty vectors following their delivery into the mouse liver by hydrodynamic tail-vein injection. We show that all β-catenin mutations, as well as WT β-catenin, are tumorigenic when co-expressed with a mutant form of yes-associated protein (YAP). However, tumor growth rates, histologies, nuclear-to-cytoplasmic partitioning, and metabolic and transcriptional landscapes were strongly influenced by the identities of the β-catenin mutations. These findings provide a context for understanding at the molecular level the notable biological diversity of HB. [ABSTRACT FROM AUTHOR]

In two different mouse liver cancer models, we recently showed that a switch from oxidative phosphorylation (Oxphos) to glycolysis (the Warburg effect) is invariably accompanied by a marked decline in fatty acid oxidation (FAO) and a reciprocal increase in the activity of pyruvate dehydrogenase (PDH), which links glycolysis to the TCA cycle. We now show that short-term implementation of either medium-chain (MC) or long-chain (LC) high fat diets (HFDs) nearly doubled the survival of mice with c-Myc oncoprotein-driven hepatocellular carcinoma (HCC). Mechanistically, HFDs forced tumors to become more reliant on fatty acids as an energy source, thus normalizing both FAO and PDH activities. More generally, both MC- and LC-HFDs partially or completely normalized the expression of 682 tumor-dysregulated transcripts, a substantial fraction of which are involved in cell cycle control, proliferation and metabolism. That these same transcripts were responsive to HFDs in livers strongly suggested that the changes were the cause of tumor inhibition rather than its consequence. In seven different human cancer cohorts, patients with tumors containing high ratios of FAO-related:glycolysis-related transcripts had prolonged survival relative to those with low ratios. Furthermore, in 13 human cancer types, the expression patterns of transcripts encoding enzymes participating in FAO and/or cholesterol biosynthesis also correlated with significantly prolonged survival. Collectively, our results support the idea that the survival benefits of HFDs are due to a reversal of the Warburg effect and other tumor-associated metabolic and cell cycle abnormalities. They also suggest that short-term dietary manipulation, either alone or in combination with more traditional chemotherapeutic regimens, might be employed as a relatively non-toxic and cost-effective means of enhancing survival in certain cancer types. [ABSTRACT FROM AUTHOR]

Eukaryotic cell metabolism consists of processes that generate available energy, such as glycolysis, the tricarboxylic acid (TCA) cycle, and oxidative phosphorylation (Oxphos), and those that consume it, including macromolecular synthesis, the maintenance of ionic gradients, and cellular detoxification. By converting pyruvate to acetyl-CoA (AcCoA), the pyruvate dehydrogenase (PDH) complex (PDC) links glycolysis and the TCA cycle. Surprisingly, disrupting the connection between glycolysis and the TCA cycle by inactivation of PDC has only minor effects on cell replication. However, the molecular basis for this metabolic re-equilibration is unclear. We report here that CRISPR/Cas9-generated PDH-knockout (PDH-KO) rat fibroblasts reprogrammed their metabolism and their response to short-term c-Myc (Myc) oncoprotein overexpression. PDH-KO cells replicated normally but produced surprisingly little lactate. They also exhibited higher rates of glycolysis and Oxphos. In addition, PDH-KO cells showed altered cytoplasmic and mitochondrial pH, redox states, and mitochondrial membrane potential (ΔΨM). Conditionally activated Myc expression affected some of these parameters in a PDH-dependent manner. PDH-KO cells had increased oxygen consumption rates in response to glutamate, but not to malate, and were depleted in all TCA cycle substrates between α-ketoglutarate and malate despite high rates of glutaminolysis, as determined by flux studies with isotopically labeled glutamine. Malate and pyruvate were diverted to produce aspartate, thereby potentially explaining the failure to accumulate lactate. Weconclude thatPDH-KO cells maintain proliferative capacity by utilizing glutamine to supply high rates of AcCoA-independent flux through the bottom portion of the TCA cycle while accumulating pyruvate and aspartate that rescue their redox defects. [ABSTRACT FROM AUTHOR]

Although the effects of job characteristics on employee motivation and commitment are broadly researched, questions remain to the extent that job characteristics influence perceived specific attitudes and behaviours of employees. It is particularly interesting to what extent the process is reinforced by supervisors, namely through their support perceived by employees and vertical trust. Survey data were collected from 550 front-line employees across a variety of industries in Poland. A structural equation modelling analysis was performed to delineate the relationship between job characteristic and employee loyalty with the mediating influence of perceived supervisory support and the trust between the supervisor and employee, which is labelled as vertical trust. We confirmed that employees who have a strong job-role fit with the characteristics of their job will have a higher level of employee loyalty than those employees who lack a strong job-role fit. Furthermore, this relationship is enhanced by the perceived supervisory support and vertical trust. Few studies have been devoted so far to the relationship between job characteristic and loyalty, and even less have been conducted in Central and Eastern European countries. The findings of our study offer new perspectives to examine loyalty dimension. We propose to distinguish a construct labelled employee loyalty which is oriented on both the organization and co-workers and as such it may be treated as a supplementary construct to OCBs' organizational loyalty. Our study is one of a few that investigates the mediating role of vertical trust and perceived supervisor support in the relationships between job characteristics and loyalty. In the literature, the need to explore the mediating mechanisms between the effects of job characteristics on employee behaviors have been repeatedly stressed. [ABSTRACT FROM AUTHOR]