Vibrational analysis of Ag3(PO2NH)3, Na3(PO2NH)3.H2O, Na3(PO2NH)3.4H2O, [C(NH2)3]3(PO2NH)3.H2O and (NH4)4(PO2NH)4.4H2O

FT IR and FT Raman spectra of Ag3(PO2NH), (Compound I), Na3(PO2NH)3.H2O (Compound II), Na3(PO2NH)3.4H2O (Compound III), [C(NH2)3]3(PO2NH)3.H2O (Compound IV) and (NH4)4(PO2NH)4.4H2O (Compound V) are recorded and analyzed on the basis of the anions, cations and water molecules present in each of them. The PO2NH− anion ring in compound I is distorted due to the influence of Ag+ cation. Wide variation in the hydrogen bond lengths in compound III is indicated by the splitting of the v2 and v3 modes of vibration of water molecules. The NH4 ion in compound V occupies lower site symmetry and exhibits hindered rotation in the lattice. The correlations between the symmetric and asymmetric stretching vibrations of P-N-P bridge and the P-N-P bond angle have also been discussed

Developmental disruption of perineuronal nets in the medial prefrontal cortex after maternal immune activation

© The Author(s) 2016. Maternal infection during pregnancy increases the risk of offspring developing schizophrenia later in life. Similarly, animal models of maternal immune activation (MIA) induce behavioural and anatomical disturbances consistent with a schizophrenia-like phenotype in offspring. Notably, cognitive impairments in tasks dependent on the prefrontal cortex (PFC) are observed in humans with schizophrenia and in offspring after MIA during pregnancy. Recent studies of post-mortem tissue from individuals with schizophrenia revealed deficits in extracellular matrix structures called perineuronal nets (PNNs), particularly in PFC. Given these findings, we examined PNNs over the course of development in a well-characterized rat model of MIA using polyinosinic-polycytidylic acid (polyI:C). We found selective reductions of PNNs in the PFC of polyI:C offspring which did not manifest until early adulthood. These deficits were not associated with changes in parvalbumin cell density, but a decrease in the percentage of parvalbumin cells surrounded by a PNN. Developmental expression of PNNs was also significantly altered in the amygdala of polyI:C offspring. Our results indicate MIA causes region specific developmental abnormalities in PNNs in the PFC of offspring. These findings confirm the polyI:C model replicates neuropathological alterations associated with schizophrenia and may identify novel mechanisms for cognitive and emotional dysfunction in the disorder

Temperature periodicities in the mid-latitude middle atmosphere and their possible association with sunspot cycle

92-95Metrocket temperature (T) data from 580 individual soundings in the 15-80 km region over Volgograd (49°N, 44°E, station index 34560) as well as sunspot number (R) data during 1971-82 were used for studying the temperature periodicities in the mid-latitude middle atmosphere and their possible association with sunspot cycle. These two variables T and R formed a pair of discrete time series with length N = 144 and sampling interval h = 1 month. Using the Blackman-Turkey approach of spectrum analysis [Blackman R B & Turkey J W, The Measurement of Power Spectra, Dower, New York, 1958], the auto- and cross-spectral estimates for 10-km steps in the 15-80 km altitude region were obtained between T and R as done in our earlier work [Planet & Space Sci (GB), 35 (1987) 959], With the Nyqvist frequency fN=0.5 cycle/month and lag variable m = 14 months. The estimated spectra were subjected to x2-test with 95% confidence level for acceptance with each harmonic fluctuation present in the spectra at 20 degrees of freedom. The presence of long-term effect of solar activity on temperature was found. The computations were carried out using CYBER 170 facility at the Vikram Sarabhai Space Centre, Trivandrum

Stratospheric and mesospheric temperatures and solar activity

The response of the stratospheric and mesospheric mean temperatures to the variations m 10.7 cm solar radio flux during a 11-year solar cycle has been investigated. This involves the correlation and regression studies between the annual mean 10.7 cm solar radio flux and the annually averaged temperatures for the two regions of the atmosphere, over Thumba (8 deg. N, 77 deg. E), India, during the period 1970-1980. A highly significant positive correlation (0.94) exists between these two parameters in the mesosphere. The correlation coefficient ( -0.28) in the stratosphere is insignificant. The calculated regression coefficients of -0.006 deg. C/unit flux and + 0.096 deg. C/unit flux for the stratosphere and mesosphere, respectively, point out clearly that the 10.7 cm solar radio flux influences strongly only in the mesosphere over the station studied, which supports the earlier findings by Ramakrishna and Seshamani ( 1973) based on one year data.</jats:p

Equatorial stratospheric and mesospheric temerature &amp; sunspot cycle

Stratospheric and mesospheric temperature variation during a Sunspot maximum (1970) and  a minimum (1976) has been analysed at five equatorial sites, viz.. Ascension Island (8° S, 14° W), Antigua (17° N,62° W), Fort Sherman (9° N, 80" W), Kwajalein (9° N, 168° E) and Thumba, Trivandrum (8° N 77° E). The investigation is based on monthly mean temperature of the four seasons in each Period. The stratospheric and mesospheric layers showed a heating effect during the period of sunspot maximum.  The heating is more pronounced in the stratospheric layers between 30 &amp; 35 km altitude. A warmer stratopause is observed over all the equatorial stations except over Thumba, where the soundings were usually taken during the post-sunset period. Seasonal variation of the thermal structure due to the solar cycle IS the least In the stratosphere. The warming produced In the stratopause is high In summer over Antigua, but over Fort Sherman and Ascension Island, the warming is slightly higher in winter. In the winter season large variations of temperature (of the order of 25° C) are observed in the upper mesosphere over Thumba, while there is least variation in spring. A high degree of mesospheric warming is clearly seen when the sun is more active. An attempt has been made to study the correlation between the temperature variation of the stratopause and the solar cycle.</jats:p

FT RAMAN AND FTIR SPECTRA OF FOUR DISELENITES <font>PbSe</font>₂<font>O</font>₅, <font>CdSe</font>₂<font>O</font>₅, <font>MnSe</font>₂<font>O</font>₅ and <font>Cr</font>₂(<font>Se</font>₂<font>O</font>₅)₃

The vibrational spectra of Lead diselenite, Cadmium diselenite, Manganese diselenite and chromium diselenite have been recorded and analysed on the basis of vibrations due to [Formula: see text] ion. The observed spectra clearly indicate the presence of diselenite group in all these compounds. The spectral analysis confirms the orthorhombic nature of MnSe 2 O 5 as suggested by Koskenlinna et al. A large number of vibrational bands in the symmetric stretching region of PhSe 2 O 5 is due to the existence of different Se-O bond lengths. From the spectra it can be seen that the anion is highly distorted angularly in chromium compound. This high distortion in all modes confirms the presence of three crystallographically distinct diselenite groups in chromium compound. </jats:p