Traceless synthesis of diketopiperazine fused tetrahydro-β-carbolines on soluble polymer support

Abstract  

The Pictet–Spengler reaction, using polyethylene glycol immobilized tryptophan ester with a variety of ketones, was achieved by refluxing condition in acidic chloroform. The linear as well as cyclic ketones were employed. All the ketones were reacted within 6–8 h to furnish soluble polymer-supported tetrahydro-β-carboline in good yields. Further expansion at N-terminus of tetrahydro-β-carbolines was achieved through a reaction with chloroacetyl chloride. Finally, the 2,5-diketopiperazine skeleton was constructed over a β-carboline by amination of the resulting N-chloroacetamides and subsequent intramolecular cyclization leading to cleavage of the polymer; constitutes a traceless synthesis of tetracyclic molecular architecture. Significantly, this strategy affords a straightforward and efficient approach for the construction of biological promising molecules with high purity and good yields.     

Evaluation of recombinant invasive, non-pathogenic Eschericia coli as a vaccine vector against the intracellular pathogen, Brucella

Background  

There is no safe, effective human vaccine against brucellosis. Live attenuated Brucella strains are widely used to vaccinate animals. However these live Brucella vaccines can cause disease and are unsafe for humans. Killed Brucella or subunit vaccines are not effective in eliciting long term protection. In this study, we evaluate an approach using a live, non-pathogenic bacteria (E. coli) genetically engineered to mimic the brucellae pathway of infection and present antigens for an appropriate cytolitic T cell response.     

Age-related delay in information accrual for faces: Evidence from a parametric, single-trial EEG approach

Background  

In this study, we quantified age-related changes in the time-course of face processing by means of an innovative single-trial ERP approach. Unlike analyses used in previous studies, our approach does not rely on peak measurements and can provide a more sensitive measure of processing delays. Young and old adults (mean ages 22 and 70 years) performed a non-speeded discrimination task between two faces. The phase spectrum of these faces was manipulated parametrically to create pictures that ranged between pure noise (0% phase information) and the undistorted signal (100% phase information), with five intermediate steps.     

Green chemistry approaches to the regioselective synthesis of spiro heterobicyclic rings using iodine as a new and efficient catalyst under solvent-free conditions

Abstract  

Iodine catalyzes the pseudo four-component reaction of an aldehyde, a urea or thiourea, and cyclic 1,3-dicarbonyl compounds under microwave irradiation in a solvent-free condition to yield various σ symmetric spiro heterobicyclic rings in excellent yields.     

From perception to action: phase-locked gamma oscillations correlate with reaction times in a speeded response task

Background  

Phase-locked gamma oscillations have so far mainly been described in relation to perceptual processes such as sensation, attention or memory matching. Due to its very short latency (≈90 ms) such oscillations are a plausible candidate for very rapid integration of sensory and motor processes.     

Growth Cone Pathfinding: a competition between deterministic and stochastic events

Background  

Growth cone migratory patterns show evidence of both deterministic and stochastic search modes.     

Evidence for a wide extra-astrocytic distribution of S100B in human brain

Background  

S100B is considered an astrocytic in-situ marker and protein levels in cerebrospinal fluid (CSF) or serum are often used as biomarker for astrocytic damage or dysfunction. However, studies on S100B in the human brain are rare. Thus, the distribution of S100B was studied by immunohistochemistry in adult human brains to evaluate its cell-type specificity.     

A new way to rapidly create functional, fluorescent fusion proteins: random insertion of GFP with an in vitro transposition reaction

Background  

The jellyfish green fluorescent protein (GFP) can be inserted into the middle of another protein to produce a functional, fluorescent fusion protein. Finding permissive sites for insertion, however, can be difficult. Here we describe a transposon-based approach for rapidly creating libraries of GFP fusion proteins.     

Deletion of the alpha-synuclein locus in a subpopulation of C57BL/6J inbred mice

Background  

The presynaptic protein α-synuclein is involved in a range of neurodegenerative diseases. Here we analyze potential compensatory mechanisms in α-synuclein null mutant mice. Furthermore, the findings reveal problems that may be associated with inbred mouse strains.     

Breakup modes of a laminar hollow water jet

Graphical Abstract  

     

Synthesis of cyano-2,3-dihydropyrrolo[1,2-<Emphasis Type="Italic">f</Emphasis>]phenanthridine derivatives via a domino-Knoevenagel-cyclization

Abstract  

In a new multicomponent reaction phenanthridine reacts with isocyanides and malonitrile in the presence of benzaldehyde derivatives to produce 2-aryl-3-(alkyl- or arylimino)-2,3-dihydropyrrolo[1,2-f]phenanthridine-1,1(12b H)-dicarbonitrile in a simple, mild, and efficient protocol in excellent yields.     

Non-rapid eye movement sleep with low muscle tone as a marker of rapid eye movement sleep regulation

Background  

It was recently reported that epochs of non-REM sleep (NREMS) with low muscle tone represent a partial correlate of REM sleep (REMS). To further investigate this phenomenon, episodes of restricted night-time sleep (23:00 – 03.00h) and subsequent morning sleep (10:00 – 13:00h) were analysed.     

Visualizations of the flow around a swimmer in turbulent regime

Graphical abstract  

     

Synthesis of novel 4H-pyrimido[1,6-a]pyrimidines via a one-pot three-component condensation

Abstract  

Highly substituted novel 4H-pyrimido[1,6-a] pyrimidines were prepared by a trifluoromethanesulfonic acid catalyzed one-pot three-component condensation of 4-aminopyrimidines, aldehydes, and β-ketoesters. A preliminary feasibility study was undertaken on these compounds, to assess the potential production of a library of further diversified compounds by nucleophilic replacement of Cl (R¹) or by reaction of electrophiles with the NH₂ (R²) group.     

MMP-28 as a regulator of myelination

Background  

Matrix metalloproteinase-28 (MMP-28) is a poorly understood member of the matrix metalloproteinase family. Metalloproteinases are important mediators in the development of the nervous system and can contribute to the maturation of the neural micro-environment.     

The life of a vortex in an axisymmetric jet

Graphical Abstract  

     

Flow visualization of supersonic transverse jet over Mach 2 freestream of a sharp cone

Graphical abstract  

     

Two-layer exchange flows over a dune: effect of large-scale bottom roughness

Graphical Abstract  

     

Neuropeptide delivery to the brain: a von Willebrand factor signal peptide to direct neuropeptide secretion

Background  

Multiple neuropeptides, sometimes with opposing functions, can be produced from one precursor gene. To study the roles of the different neuropeptides encoded by one large precursor we developed a method to overexpress minigenes and establish local secretion.