Terahertz-based nanometrology: multispectral imaging of nanoparticles and nanoclusters in suspensions

Silica nanoparticles suspended in an organic solvent (nanosuspension) have been imaged and characterized via terahertz nanoscanning reconstructive three-dimension (3D) imaging technique. The size of individual silica nanoparticles in the suspension was quantified. In addition, the presence of nanoclusters along with their distribution in the suspension was visualized in 3D. It has also been qualitatively demonstrated that the volume fraction of solvent is significantly higher than that of the silica nanoparticles; an observation consistent with the composition of the nanosuspension in the present investigation. The measured size range of individual nanoparticles was found to be 10–12 nm, while the manufacturer’s specification indicates a nanoparticle size distribution in the range of 10 to 15 nm. However, a typical nanocluster size was determined to be 17.5 nm, thus indicating the presence of nanoparticles less than 10 nm. The nanometrology instrument used in this investigation was based on a dendrimer dipole excitation-based continuous wave terahertz source generating >?200 mW stable terahertz power.     

Solid State Structure of 6,7-Dihydro-1,4-Di(2′-Pyridyl)-5<Emphasis Type="Italic">H</Emphasis>-Cyclopenta[d]Pyridazine

Abstract  The X-ray structure of 6,7-dihydro-1,4-di(2′-pyridyl)-5H-cyclopenta[d]pyridazine ligand (5-dppn) shows the existence of a trans/trans conformation. The 5-dppn crystallizes in a triclinic space group P-1 with a = 7.1048(15) ?; b = 9.008(2) ?; c = 10.986(3) ?; α = 88.279(16)°; β = 85.454(15)°; γ = 69.104(12)°; V = 654.7(3) ?³ and Z = 2. The analysis of 5-dppn crystal structure demonstrates the presence of edge-edge Ar–H···N and face-face Aliph-H···N centrosymmetric dimer interactions. The unit cell packing arrangement confirmed the presence of two molecules opposite to each other. Index Abstract  The X-ray structure of 6,7-dihydro-1,4-di(2′-pyridyl)-5H-cyclopenta[d]pyridazine ligand (5-dppn) shows the existence of a trans/trans conformation.      

Synthesis of substituted 3,4-dihydrofuro[2,3-d]pyrimidines from 3-arylmethylidenefuran-2(3H)-ones

Russian Journal of Organic Chemistry -     

Modeling the flow-level performance of hierarchical modulation in?OFDMA-based networks

Hierarchical Modulation (HM) is a means to enhance the spectral efficiency of a system by superposing, in terms of modulation, an additional stream for a given user with good radio conditions on a basic stream of a user with worse radio conditions. This, in turn, increases the throughput of the former user and hence the overall performance of the whole system. We consider, in this work, such a performance at the flow level, for a realistic dynamic setting where users come to the system and leave it after a finite duration corresponding, for instance, to the completion of a file transfer. We specifically model and quantify, both analytically and via simulations, the gain thus achieved and propose two extensions to the basic HM algorithm: a first one in which a user with bad radio conditions is also superposed on one with better radio conditions and a second one in which a user of one type is further superposed on a user of the same type as well.     

Interference-free energy efficient scheduling in wireless ad hoc networks

This paper studies the problem of interference-free broadcast in wireless ad hoc networks. In particular, we are interested in asymmetric power assignments so that the induced broadcast communication graph is both, energy efficient and has a short collision-free broadcast schedule. We consider both random and deterministic node layouts and develop four different broadcast schemes with provable performance guarantees on three optimization objectives simultaneously: total energy consumption, network lifetime and collision-free schedule length. We also show extensive numerical results which support our findings.     

Phytochemical analysis, cytotoxic activity and constituents-activity relationships of the leaves of Cinnamomum iners (Reinw. ex Blume-Lauraceae)

The leaves of Cinnamomum iners (Reinw. ex Blume-Lauraceae) have been refluxed successively with chloroform and alcohol to get chloroform extract and alcoholic extract. Both the extracts have been assayed for cytotoxicity against human colorectal tumour cells. The chloroform extract exhibited significant cytotoxicity with IC(50) 31?μg mL(-1) (p??200?μg mL(-1). The chloroform extract has been further proceeded for chemical analysis by GC-TOFMS and 178 components were identified including acids, amines, amides, aldehydes, alcohols, esters, benzene derivatives, bicyclic compounds, terpenes, hydrocarbons, naphthalene derivatives, furan derivatives, azulenes, etc. Nine components representing 51.73% of the total chloroform extract were detected as major components. Caryophyllene (14.41%) and Eicosanoic acid ethyl ester (12.17%) are the most prominent components of the chloroform extract. β-Caryophyllene (14.41%) as most abundant compound supports potent cytotoxicity as shown by chloroform extract.     

Palladium(ii) driven self-assembly of a saturated quadruple-stranded metallo helicate

Complexation of the bridging bidentate ligand N,N'-(pyridine-2,6-diyl)dinicotinamide, L with palladium(ii) resulted in a single discrete M(2)L(4) self-assembly, 1, in a quantitative manner. The entropically-controlled assembly of 1 resulted in a rare saturated, quadruple-stranded metallo-helicate, in which both the left-handed (M) and right-handed (P) helicates exist in the crystal structure.     

Acceleration of Adventitious Shoots by Interaction Between Exogenous Hormone and Adenine Sulphate in Althaea Officinalis L.

In the current study attempts were made to investigate the effects of three different phases of callus induction followed by adventitious regeneration from leaf segments (central and lateral vein). Callus induction was observed in Murashige and Skoog’s (MS) medium supplemented with 15.0 μM 2,4-dichloro phenoxy acetic acid (2,4-D). Adventitious shoot buds formation was achieved on MS medium supplemented with 7.5 μM 2,4-D and 20.0 μM AdS in liquid medium as it induced 19.2?±?0.58 buds in central vein explants. Addition of different growth regulators (cytokinins—6-benzyladenine, kinetin and 2-isopentenyl adenine alone or in combination with auxins—indole-3-acetic acid, indole-3-butyric acid and α-naphthalene acetic acid, improved the shoot regeneration efficiency, in which 5.0 μM 6-benzyl adenine along with 0.25 μM α-naphthalene acetic acid was shown to be the most effective medium for maximum shoot regeneration (81.3 %) with 24.6 number of shoots and 4.4?±?0.08 cm shoot length per explant. Leaf culture of central veins led to better shoot formation capacity in comparison to lateral vein. Rooting was readily achieved on the differentiated shoots on 1/2 MS medium augmented with 20.0 μM indole-3-butyric acid. The plants were successfully hardened off in sterile soilrite followed by their establishment in garden soil with 80 % survival rate.     

A novel and facile reaction to N6‐alkylated adenosine via benzotriazole as a synthetic auxiliary

The reaction of benzotriazole with aliphatic, aromatic or heteroaromatic aldehyde and adenosine leads to a benzotriazole adduct which is reduced with sodium borohydride to the corresponding N⁶‐alkylated adenosine derivatives. This procedure is also utilized in a new route to N⁶‐(3‐iodobenzyl)adenosine‐5′‐N‐methyluronamide (IB‐MECA) which is considered an important adenosine agonist at A₃ adenosine receptors.