PRODUCTS OF ULTRAFILTERS AND MAXIMAL LINKED SYSTEMS ON WIDELY UNDERSTOOD MEASURABLE SPACES

Constructions related to products of maximal linked systems (MLSs) and MLSs on the product of widely understood measurable spaces are considered (these measurable spaces are defined as sets equipped with \(\pi\)-systems of their subsets; a \(\pi\)-system is a family closed with respect to finite intersections). We compare families of MLSs on initial spaces and MLSs on the product. Separately, we consider the case of ultrafilters. Equipping set-products with topologies, we use the box-topology and the Tychonoff product of Stone-type topologies. The properties of compaction and homeomorphism hold, respectively.

Design of a Scalable 4G Portable Network Using Low Cost SDR And Raspberry Pi

Of late, Software Defined Radio (SDR) approach has become an effective means to design high data rate wireless systems for a range of applications. There are methods with which low cost SDR based 4th generation (4G) or long term evolution (LTE) systems can be designed. Using low cost Raspberry Pi systems, the SDR aided 4G systems can be designed for high data rate communication. The work is related to the design of a 4G wireless system using low cost SDR solutions and integrated to a programmable controller based on a Raspberry Pi. Experimental results show that the system is effective in a range of conditions

Water reuse and growth inhibition mechanisms for cultivation of microalga Euglena gracilis

Background Microalgae can contribute to more than 40% of global primary biomass production and are suitable candidates for various biotechnology applications such as food, feed products, drugs, fuels, and wastewater treatment. However, the primary limitation for large-scale algae production is the fact that algae requires large amounts of fresh water for cultivation. To address this issue, scientists around the world are working on ways to reuse the water to grow microalgae so that it can be grown in successive cycles without the need for fresh water. Results In this study, we present the results when we cultivate microalgae with cultivation water that is purified and reused. Specifically, we purify the cultivation water using an ultrafiltration membrane (UFM) treatment and investigate how this treatment affects: the biomass and biochemical components of the microalgae; characteristics of microalgae growth inhibitors; the mechanism whereby potential growth inhibitors are secreted (followed using metabolomics analysis); the effect of activated carbon (AC) treatment and advanced oxidation processes (AOPs) on the removal of growth inhibitors of Euglena gracilis. Firstly, the results show that E. gracilis can be only cultivated through two growth cycles with water that has been filtered and reused, and the growth of E. gracilis is significantly inhibited when the water is used a third time. Secondly, as the number of reused water cycles increases, the Cl− concentration gradually increases in the cultivation water. When the Cl− concentration accumulates to a level of fivefold higher than that of the control, growth of E. gracilis is inhibited as the osmolality tolerance range is exceeded. Interestingly, the osmolality of the reused water can be reduced by replacing NH4Cl with urea as the source of nitrogen in the cultivation water. Thirdly, E. gracilis secretes humic acid (HA)—which is produced by the metabolic pathways for valine, leucine, and isoleucine biosynthesis and by linoleic acid metabolism—into the cultivation water. Because HA contains large fluorescent functional groups, specifically extended π(pi)-systems containing C=C and C=O groups and aromatic rings, we were able to observe a positive correlation between HA concentration and the rate of inhibition of E. gracilis growth using fluorescence spectroscopy. Moreover, photosynthetic efficiency is adversely interfered by HA, thereby reductions in the synthetic efficiency of paramylon and lipid in E. gracilis. In this way, we are able to confirm that HA is the main growth inhibitor of E. gracilis. Finally, we verify that all the HA is removed or converted into nutrients efficiently by AC or UV/H2O2/O3 treatments, respectively. As a result of these treatments, growth of E. gracilis is restored (AC treatment) and the amount of biomass is promoted (UV/H2O2/O3 treatment). Conclusions These studies have important practical and theoretical significance for the cyclic cultivation of E. gracilis and for saving water resources. Our work may also provide a useful reference for other microalgae cultivation.

Helical Electronic Transitions of Spiroconjugated Molecules

<div><div><div><div><p>The two pi-systems of allene can mix into helical molecular orbitals (MOs), yet the helicity is lost in the pi-pi∗ transitions. In spiroconjugated molecules the relative orientation of the two π- systems is different as only half the pi-MOs become helical. Consequently, the helicity of the electronic transitions is symmetry protected and thus helical pi-conjugation can manifest in observable electronic and chiroptical properties.</p></div></div></div></div>

Naphthyl-Fused Phosphepines: Luminescent Contorted Polycyclic P-Heterocycles

The article presents the synthesis of a new family of naphthyl-fused phosphepines through Ni-mediated C-C coupling. Interestingly, the chloro-phosphine-oxide intermediate shows strong resistance toward oxidation/hydrolysis due to a combination of steric hindrance and pnictogen interactions. However it can undergo substitution reactions under specific conditions. The optical / redox properties and the electronic structure of these new pi-systems were studied experimentally and computationally. Taking advantage of the luminescence of these derivatives, a blue emitting OLED has been prepared highlighting that these novel pi-conjugated P-heterocycles appear as promising building blocks for solid-state lightning applications.

Naphthyl-Fused Phosphepines: Luminescent Contorted Polycyclic P-Heterocycles

The article presents the synthesis of a new family of naphthyl-fused phosphepines through Ni-mediated C-C coupling. Interestingly, the chloro-phosphine-oxide intermediate shows strong resistance toward oxidation/hydrolysis due to a combination of steric hindrance and pnictogen interactions. However it can undergo substitution reactions under specific conditions. The optical / redox properties and the electronic structure of these new pi-systems were studied experimentally and computationally. Taking advantage of the luminescence of these derivatives, a blue emitting OLED has been prepared highlighting that these novel pi-conjugated P-heterocycles appear as promising building blocks for solid-state lightning applications.

An Effective Synthesis of N,N-Diphenyl Carbazolium Salts

Tetraaryl ammonium salts are a synthetic challenge, since there is no general method for the arylation of triaryl amines. Contrary to other quaternary ammonium salts, tetraaryl ammonium salts should be very chemically stable. The ipso carbons are not very electrophilic, since the positive charge is distributed throughout the pi systems and they have no acidic β hydrogens. Here we demonstrate a simple approach to N,N-diphenyl carbazolium salts using only three synthetic steps, allowing for an easy production of these salts in large amounts and in a relatively short time. In addition, we study the Cu(I) catalyzed multi-arylation of 2,2’-diaminobiphenyl, focusing on the regioselectivity of each step. Finally, we characterize, for the first time, the solid state structure of a tetraaryl ammonium salt.

Large pi-systems containing W–N=N–W groups

The compound Cl–W(Mes)3–N=N–W(Mes)3–Cl can polymerize, giving large inorganic pi systems containing N2 and W(Mes)3, where Mes = mesityl. Some of these compounds have been studied in the present paper using B3LYP functional. A description of the molecular orbitals from the pi system is given, explaining the role of the mesityl groups, the terminal chlorines, and the d atomic orbitals from W in the whole conjugated system. Other data such as bond order, atomic partial charges, or geometry are studied. These compounds are also compared with some hypothetical derivatives.