Screening effect of impurities in metals: a possible explanation of the process of cold nuclear fusion

Summary The screening length of the deuterium ion by surrounding electrons in a palladium metal lattice, as estimated using two approaches—viz. the Thomas-Fermi screening theory and the Debye screening theory for plasmas in metal—is found to be less than the interatomic separation of ordinary hydrogen molecules. This has important implications for the possibility of cold nuclear fusion at room temperature, since slight fluctuations in equilibrium conditions may drive the deuterons to fuse together. The relative magnitudes of screening length for the cold nuclear fusion regime and classical hot nuclear regimes (inertial and magnetic confinement) reveal that in the former a comparatively smaller amount of energy is needed to overcome the repulsive Coulomb barrier between two deuterium ions.     

Reduction of chromano–piperidine-fused isoxazolidines: Tandem intramolecular rearrangements leading to 2-(methylamino)-4-oxo-N-phenyl-N-propyl-4H-chromene-3-carboxamide

Reductive ring opening of isoxazolidine moiety of chromano–piperidine-fused isoxazolidines (3a–c) with HCOONH₄ and 10% Pd/C in a mixture of solvents (THF/MeOH) at ambient temperature, affords novel 2-(methylamino)-4-oxo-N-phenyl-N-propyl-4H-chromene-3-carboxamide (4), which is apparently derived from reductive NO bond cleavage followed by tandem intramolecular rearrangements. Plausible mechanistic rationale for the formation of compound 4 is proffered.     

Copper-catalyzed Pummerer type reaction of α-thio aryl/heteroarylacetates: Synthesis of aryl/heteroaryl α-keto esters

A copper catalyzed Pummerer type reaction of α-thio aryl/heteroarylacetates is described for the first time. This transformation represents a new route to synthesize α-keto esters, which are important intermediates for pharmaceuticals and organic synthesis. The reaction proceeds via in situ generation of a thionium ion that undergoes hydrolysis to furnish α-keto esters in synthetically viable yields (up to 82%).     

Deoxygenation of tertiary amine N-oxides under metal free condition using phenylboronic acid

A simple and efficient method for the deoxygenation of amine N-oxides to corresponding amines is reported using the green and economical reagent phenylboronic acid. Deoxygenation of N,N-dialkylaniline N-oxides, trialkylamine N-oxides and pyridine N-oxides were achieved in good to excellent yields. The reduction susceptible functional groups such as ketone, amide, ester and nitro groups are well tolerated with phenylboronic acid during the deoxygenation process even at high temperature. In addition, an indirect method for identification and quantification of tert-amine N-oxide is demonstrated using UV–Vis spectrometry which may be useful for drug metabolism studies.     

Polyaromatic heterocycles through intramolecular alkyne carbonyl metathesis: 5-Acylnaphtho[2,1-b]benzofurans

A modular approach to 5-acylated naphtho[2,1-b]benzofurans was developed where Sonogashira cross-coupling and intramolecular alkyne carbonyl metathesis were sequentially employed to build the aromatic benzene C ring of naphtho[2,1-b]benzofuran with an acyl group at the C5 position.     

An Ethenoadenine FAD Analog Accelerates UV Dimer Repair by DNA Photolyase

Reduced anionic flavin adenine dinucleotide (FADH^?) is the critical cofactor in DNA photolyase (PL) for the repair of cyclobutane pyrimidine dimers (CPD) in UV‐damaged DNA. The initial step involves photoinduced electron transfer from *FADH^? to the CPD. The adenine (Ade) moiety is nearly stacked with the flavin ring, an unusual conformation compared to other FAD‐dependent proteins. The role of this proximity has not been unequivocally elucidated. Some studies suggest that Ade is a radical intermediate, but others conclude that Ade modulates the electron transfer rate constant (k_ET) through superexchange. No study has succeeded in removing or modifying this Ade to test these hypotheses. Here, FAD analogs containing either an ethano‐ or etheno‐bridged Ade between the AN1 and AN6 atoms (e‐FAD and ε‐FAD, respectively) were used to reconstitute apo‐PL, giving e‐PL and ε‐PL respectively. The reconstitution yield of e‐PL was very poor, suggesting that the hydrophobicity of the ethano group prevented its uptake, while ε‐PL showed 50% reconstitution yield. The substrate binding constants for ε‐PL and rPL were identical. ε‐PL showed a 15% higher steady‐state repair yield compared to FAD‐reconstituted photolyase (rPL). The acceleration of repair in ε‐PL is discussed in terms of an ε‐Ade radical intermediate vs superexchange mechanism.     

Population Genetic Structure and Marker Trait Associations Using Morphological,Phytochemical and Molecular Parameters in <Emphasis Type="Italic">Habenaria edgeworthii</Emphasis>—a Threatened Medicinal Orchid of West Himalaya,India

Habenaria edgeworthii Hook. f. ex Collett is an important terrestrial orchid used in different Ayurvedic formulations. In the present study, variations among morphological, phytochemical and molecular markers were assessed. A significant difference was observed among populations using morphological traits. Inter-simple sequence repeat (ISSR) data revealed lower genetic diversity at population level (He = 0.207) as compared to species level (He = 0.334). Analysis of molecular variance (AMOVA) indicates 74 % variation among populations and 26 % within population. Tuber extracts showed significantly (p < 0.05) higher total phenolics and flavonoids among the populations. Antioxidant activity determined by 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) assays exhibited considerable antioxidant potential. Furthermore, the associations between molecular and morphological and phytochemical attributes were studied using multiple regression analysis (MRA). Several ISSR fragments were associated with some morphological and phytochemical traits. These ISSR fragments can be useful for breeding programme of the species when no other genetic information, such as linkage maps and quantitative trait loci, is available.     

Molecular Cloning and Characteristic Features of a Novel Extracellular Tyrosinase from <Emphasis Type="Italic">Aspergillus niger</Emphasis> PA2

Biofertilizers have been widely used in many countries for their benefit to soil biological and physicochemical properties. A new microbial biofertilizer containing Phanerochaete chrysosporium and Bacillus thuringiensis was prepared to decrease nicotine content in tobacco leaves by regulating soil nitrogen supply. Soil NO₃ ^?-N, NH₄ ⁺-N, nitrogen supply-related enzyme activities, and nitrogen accumulation in plant leaves throughout the growing period were investigated to explore the mechanism of nicotine reduction. The experimental results indicated that biofertilizer can reduce the nicotine content in tobacco leaves, with a maximum decrement of 16–18 % in mature upper leaves. In the meantime, the total nitrogen in mature lower and middle leaves increased with the application of biofertilizer, while an opposite result was observed in upper leaves. Protein concentration in leaves had similar fluctuation to that of total nitrogen in response to biofertilizer. NO₃ ^?-N content and nitrate reductase activity in biofertilizer-amended soil increased by 92.3 and 42.2 %, respectively, compared to those in the control, whereas the NH₄ ⁺-N and urease activity decreased by 37.8 and 29.3 %, respectively. Nitrogen uptake was improved in the early growing stage, but this phenomenon was not observed during the late growth period. Nicotine decrease is attributing to the adjustment of biofertilizer in soil nitrogen supply and its uptake in tobacco, which result in changes of nitrogen content as well as its distribution in tobacco leaves. The application of biofertilizer containing P. chrysosporium and B. thuringiensis can reduce the nicotine content and improve tobacco quality, which may provide some useful information for tobacco cultivation.