Effect of photons on the magnon splitting

The self energy of a uniform magnon due to splitting into two magnons of oppositely directed momenta is calculated in the presence of a magnon-photon interaction, and it is found that the magnons and the photons form excitations of mixed character. Thus there is a net correction to the magnon splitting due to an interference.     

Overlap contribution to internal conversion coefficients of the 14.4 keV M1 transition in 57Fe

It is suggested that while evaluating contact charge densities from internal conversion coefficients it is important to consider overlap effects. Ratios of the internal conversion coefficients

and

are evaluated as a function of interatomic separation for Fe³⁺ in an octahedral arrangement of Br^? ions.     

Identification and characterization of peptide: N glycanase from Dictyostelium discoideum

ABSTRACT: BACKGROUND: Peptide: N glycanase (PNG) enzyme cleaves oligosaccharides from the misfolded glycoproteins and prepares them for degradation. This enzyme plays a role in the endoplasmic reticulum associated degradation (ERAD) pathway in yeast and mice but its biological importance and role in multicellular development remain largely unknown. RESULTS: In this study, the PNG from the cellular slime mold, Dictyostelium discoideum (DdPNG) was identified based on the presence of a common TG (transglutaminase) core domain and its sequence homology with the known PNGs. The domain architecture and the sequence comparison validated the presence of probable functional domains in DdPNG. The tertiary structure matched with the mouse PNG. Here we show that DdPNG is an essential protein, required for aggregation during multicellular development and a knock out strain of it results in small sized aggregates, all of which do not form fruiting bodies. The in situ hybridization and RT PCR results show higher level of expression during the aggregate stage. The expression gets restricted to the prestalk region during later developmental stages. DdPNG is a functional peptide-N-glycanase enzyme possessing deglycosylation activity, but does not possess any significant transamidation activity. CONCLUSIONS: We have identified and characterized a novel PNG from D. discoideum and confirmed its deglycosylation activity. The results emphasize the importance of PNG in aggregation during multicellular development of this organism.     

Effect of animal drawn puddling implements on hydraulic conductivity of lateritic sandy clay loam soil in West Bengal, India

To determine out the suitable animal drawn puddling implement in terms of reduction in hydraulic conductivity of soils were investigated in this research study. In rice (Oriza sativa L.) cultivation in West Bengal, India, reduction in hydraulic conductivity of soil facilitates better rice growth. To determine, the effect of puddling implements, i.e., an animal drawn rotary puddler (I₁), a 3-tine tiller (I₂) and a local plough (I₃), and number of passes of the implements on hydraulic conductivity of the puddled as well as the non-puddled layer of a lateritic sandy clay loam with respect to relative age (i.e., elapsed time after puddling operation) was studied under controlled soil-bin conditions. It was concluded that the hydraulic conductivity of soil decreases with the number of passes and relative age. A mathematical model was developed for calculating the hydraulic conductivity of puddled soil layer. It was concluded that the hydraulic conductivity obtained with the rotary puddler was 2.27 times less than that with the 3-tine tiller and 3.09 times that with local plough after the fifth pass of puddling operations.     

X‐ray K absorption spectral studies of copper (II) hydroxamic acid mixed ligand complexes

X‐ray absorption spectra at the K‐edge of copper have been studied in copper mixed ligand complexes having hydroxamic acid as one of the ligands. The X‐ray absorption spectra have been recorded at BL‐8 Dispersive Extended X‐ray Absorption Fine Structure (EXAFS) beamline at the 2.5‐GeV INDUS‐2 Synchrotron Source, RRCAT, Indore, India. The data obtained has been processed using EXAFS data analysis program Athena. The energies of the K absorption edge, chemical shifts, edge‐widths and shifts of the principal absorption maximum in the complexes have been determined and discussed. The chemical shift data have been utilized to estimate effective nuclear charge on the absorbing atom. The normalized EXAFS spectra have been Fourier transformed. The position of the first peak in the Fourier transform gives the value of first shell bond length, which is shorter than the actual bond length as a result of energy dependence of the phase factors in the sine function of the EXAFS equation. This distance is thus the phase‐uncorrected bond length and has also been determined by Lytle, Sayers and Stern's (LSS) graphical method. The results obtained from LSS and the Fourier transformation methods are comparable with each other. The first shell bond length has also been estimated by Lytle's and Levy's methods from the EXAFS data. Copyright © 2014 John Wiley & Sons, Ltd.     

Fourier Multipliers and Littlewood‐Paley for modulation spaces

In this paper we have studied Fourier multipliers and Littlewood‐Paley square functions in the context of modulation spaces. We have also proved that any bounded linear operator from modulation space into itself possesses an l₂‐valued extension. This is an analogue of a well known result due to Marcinkiewicz and Zygmund on classical ‐spaces.     

Selective Reduction of Thiol Esters with Sodium Borohydride

A couple of years ago, Fujita and co-workers¹ reported the reduction of 2-thiazoline-2-thiol esters to alcohols with sodium borohydride in aqueous tetrahydrofuran. In connection with an ongoing synthetic project which requires the selective reduction of a stable acid derivative to the alcohol level in the presence of nitrile and ester groups, we examined the reaction of a variety of thiol esters with sodium borohydride. Our results show that the highly reactive (and thus unstable) 2-thiazoline-2-thiol ester derivatives are unnecessary and in fact various types of thiol esters are readily convertible to alcohols under mild conditions which do not effect the reduction of common acid derivatives such as nitrile, ester, and amide.     

Mobile interstitial model and mobile electron model of mechano-induced luminescence in coloured alkali halide crystals

A theoretical study is made on the mobile interstitial and mobile electron models of mechano-induced luminescence in coloured alkali halide crystals. Equations derived indicate that the mechanoluminescence intensity should depend on several factors like strain rate, applied stress, temperature, density of F-centres and volume of crystal. The equations also involve the efficiency and decay time of mechanoluminescence. Results of mobile interstitial and mobile electron models are compared with the experimental observations, which indicated that the latter is more suitable as compared to the former. From the temperature dependence of ML, the energy gaps between the dislocation band and ground state of F-centre is calculated which are 0.08, 0.072 and 0.09 eV for KCl, KBr and NaCl crystals, respectively. The theory predicts that the decay of ML intensity is related to the process of stress relaxation in crystals.     

Phonon-induced virtual states in mixed-valence systems

We propose the existence of phonon-induced virtual states in amorphous systems and calculate their width. The resonance occurs when the phonon frequency is equal to the electronic band gap. We predict the phenomenon of valencostriction, namely, the change in volume upon change in valence which provides observational evidence for the new wave functions.