Controlling activation barrier by carbon nanotubes as nano-chemical reactors

The oxidative addition of primary amine on a monocyclic phospholane was studied in confined conditions. This one-step chemical reaction has been investigated using the DFT technique to elucidate the role of confinement in carbon nanotubes on the reaction. Calculations were carried out by a progressive increase of the nanotube diameters from 10 Å to 15 Å in order to highlight the dependence of the reactivity on the nanotube diameter. First, single point investigations were dedicated to the study of reactants, transition states, and products placed in the different nanotubes while keeping their optimized structure as free compounds. Second, all studied compounds were relaxed inside nanotubes and their geometries were fully optimized. Within these approaches, we proved that the activation barrier could be controlled depending on the confinement, generating a well-controlled catalysis process.     

The many roles of small RNAs in leaf development

Leaf development involves many complex genetic interactions,signals between adjacent cells or between more distant tissues and consequent changes in cell fate.This review describes three stages in leaf development where regulation by small RNAs have been used to modulate gene expression patterns.     

Pre-expression of a sulfhydryl oxidase significantly increases the yields of eukaryotic disulfide bond containing proteins expressed in the cytoplasm of E.coli

Background  

Disulfide bonds are one of the most common post-translational modifications found in proteins. The production of proteins that contain native disulfide bonds is challenging, especially on a large scale. Either the protein needs to be targeted to the endoplasmic reticulum in eukaryotes or to the prokaryotic periplasm. These compartments that are specialised for disulfide bond formation have an active catalyst for their formation, along with catalysts for isomerization to the native state. We have recently shown that it is possible to produce large amounts of prokaryotic disulfide bond containing proteins in the cytoplasm of wild-type bacteria such as E. coli by the introduction of catalysts for both of these processes.     

Rutin ameliorates copper sulfate‐induced brain damage via antioxidative and anti‐inflammatory activities in rats

Excessive exposure to Copper (Cu) may result in Cu toxicity and adversely affect health outcomes. We investigated the protective role of rutin on Cu‐induced brain damage. Experimental rats were treated as follows: group I: control; group II: Cu‐sulfate: 200 mg/kg; group III: Cu‐sulfate, and rutin 100 mg/kg; and group IV: rutin 100 mg/kg, for 7 weeks. Cu only treatment significantly decreased body weight gain, while rutin cotreatment reversed this decrease. Cu treatment increased malondialdehyde, nitric oxide level, and myeloperoxidase activity and decreased superoxide dismutase and catalase activities in rat brain. Immunohistochemistry showed that COX‐2, iNOS, and Bcl‐2 proteins were strongly expressed, while Bax was mildly expressed in the brain of Cu‐treated rats. Furthermore, brain histology revealed degenerated neurons, and perforated laminae of cerebral cortex in the Cu‐only treated rats. Interestingly, coadministration of Cu and rutin reduced the observed histological alteration, improved inflammatory and antioxidant biomarkers, thereby protecting against Cu‐induced brain damage via antioxidative and anti‐inflammatory mechanisms.     

Experimental studies of OH° radical/pressure dependence of arginase activity using a molecular chromatography approach

Arginase is an enzyme which plays a role in pathophysiology such as hypertension. Here we demonstrated for the first time the direct implication of pressure and OH° radical formation on the arginase activity via a novel analytical procedure. Pressure increased arginase activity in the range 12–52 bars. Activation by OH° radical showed a hyperbolic response. The OH° radicals produced were significantly inhibited by sulfasalazine (SAZ) and the inhibition of OH° radicals parallels the inhibition of arginase activity.     

A model of dengue fever

Background  

Dengue is a disease which is now endemic in more than 100 countries of Africa, America, Asia and the Western Pacific. It is transmitted to the man by mosquitoes (Aedes) and exists in two forms: Dengue Fever and Dengue Haemorrhagic Fever. The disease can be contracted by one of the four different viruses. Moreover, immunity is acquired only to the serotype contracted and a contact with a second serotype becomes more dangerous.     

The encapsulation of the gemcitabine anticancer drug into grapheme nest: a theoretical study

The efficient transport of a drug molecule until its target cell constitutes a significant challenge for delivery processes. To achieve such objectives, solid nanocapsules that protect the immune system during the transport should be developed and controlled at the nanoscale level. From this point of view, nanostructures based on graphene sheets could present some promising properties due to their ultimate size and dimension. In this work, we present theoretical results using DFT calculations, dealing with a graphene-based delivery system. Indeed, we demonstrate the stability of the gemcitabine anticancer molecule when it is encapsulated into two concave graphene sheets organized as a nest. Quantum calculations showed that the most stable state is located inside the nest, which is then formed by two layers distanced 6 Å from each other. For all the optimized systems, we focused on the dependence of the interaction energy on the molecule displacements during its entrance in the graphene nest and its exit from it. We also analyzed their consequence on the local morphological and electronic charge properties.

Open image in new window

Graphical Abstract Adsorption energy (in eV) of gemcitabine drug during its encapsulation inside the nest of grapheneand its release from it

     

Inflammatory cytokines and metabolic responses to high-intensity intermittent training: effect of the exercise intensity

To examine the effects of two high-intensity intermittent training (HIIT) programs of varying intensities (100% vs. 110% of maximal aerobic velocity [MAV]) on metabolic, hormonal and inflammatory markers in young men. Thirty-seven active male volunteers were randomly assigned into: HIIT experimental groups (100% MAV [EG₁₀₀, n = 9] and 110% MAV [EG₁₁₀, n = 9]) and a control groups (CG₁₀₀, n = 9 and CG₁₁₀, n = 9). Particpants performed high intesity intermittent exercise test (HIIE) at 100% or 110% MAV. Venous blood samples were obtained before, at the end of HIIE and at 15 min of recovery, and before and after 8 weeks of HIIT programs. After training, Glucose was lower (p < 0.01) in EG₁₀₀ (d = 0.72) and EG₁₁₀ (d = 1.20) at the end of HIIE, and at 15 min recovery only in EG₁₁₀ (d = 0.95). After training, Insulin and Cortisol were lower than before training in EG₁₀₀ and EG₁₁₀ at the end of HIIE (p < 0.001). After HIIT, IL-6 deceased (p < 0.001) in EG₁₀₀ (d = 1.43) and EG₁₁₀ (d = 1.56) at rest, at the end of HIIE (d = 1.03; d = 1.75, respectively) and at 15 min of recovery (d = 0.88;d = 1.7, respectively). This decrease was more robust (p < 0.05) in EG₁₁₀ compared to EG₁₀₀. After HIIT, TNF-α deceased (p < 0.001) in EG₁₀₀ (d = 1.43) and EG₁₁₀ (d = 0.60) at rest, at the end of HIIE (0.71 < d < 0.98) and at 15 min of recovery (0.70 < d < 2.78). HIIT with 110% MAV is more effective in young males on the improvements of some metabolic (Glucose), hormonal (Cortisol) and inflammatory (IL-6) markers at rest, at the end of HIIE and 15 min of recovery than training at 100 % MAV.