Echo-Doppler angle determination for noninvasive transmitral blood velocity calculations in normal and porcine bioprosthetic mitral valves

Doppler incident angle (DA) determination is a critical factor in the noninvasive attempt to measure transmitral blood velocity (TMBV) and to estimate volumetric flow. The error in TMBV varies with the cosine of DA. Using an echo-Doppler duplex scanner (DS), we studied transmitral flow velocities in 10 normal subjects (Group I) and 10 asymptomatic patients with procine mitral valve (PMV) bioprostheses. A 3-MHz scanhead with three medium focused rotating transducers was positioned at the left ventricular apex, and standard apical four-chamber views of the heart were obtained. The position of the Doppler sample volume (SV) was adjusted within the valve orifice until the maximal power of the Doppler audio spectra reflecting TMBV was recorded by a spectral analyzer. At this location of the SV, images were recorded and protractors were used to estimate DA. DA ranged from 10 to 40 degrees (x = 22.5 degrees +/- 10.8 degrees) in Group I and from 0 to 15 degrees (x = 4.5 degrees +/- 5.0 degrees) in Group II. Mean values of DA in Groups I and II were significantly different (p less than 0.01). We conclude: (1) in normal subjects, DA measured from the apex into the MV varies significantly and thus may compromise the accuracy of TMBV measurements; (2) the truncated funnel shape of the stent of the PMV bioprosthesis allows a DA less than 15 degrees and thus a smaller error in TMBV calculations.     

Residues of DDT and HCH in wheat samples collected from different states of India and their dietary exposure: A multicentre study

Under a multicentre study conducted by the Indian Council of Medical Research, 1712 samples of wheat grain/flour were collected from urban and rural areas in 11 states representing different geographical regions of India. These samples were analysed for residues of DDT (2,2-bis (p-chlorophenyl)-1,1,1-trichloro ethane) and different isomers of HCH (1,2,3,4,5,6-hexachloro cyclohexane, a mixture of isomers) by gas-liquid chromatography. Residues of DDT were detected in 59.4% of 1080 samples of wheat grain and in 78.2% of 632 samples of wheat flour. Different isomers of HCH were present in about 45-80% of the samples of wheat grain/flour. Medians of DDT and total HCH, respectively, for pooled samples of wheat grain were 0.013 and 0.035 mg kg^-1, while those for wheat flour were 0.01 and 0.02 mg kg^-1. Estimated daily intakes of DDT and different isomers of HCH through the consumption of wheat contaminated at their median and 90th percentiles constituted a small proportion of their acceptable daily intakes. Amongst the pesticide residues analysed, statutory maximum residue limits have been fixed only for γ-HCH in wheat in India, as 0.1 mg kg^-1 in wheat grain and zero in wheat flour. Residue levels of γ-HCH exceeded these maximum residue limits in five of 1080 samples of wheat grain and in 340 of 632 samples of wheat flour. The failure to meet the requirement of the γ-HCH maximum residue limit in large number of wheat flour samples was attributed to the fixation of practically unachievable zero limit. Comparing the previous studies and the present one, the levels of residues of DDT and HCH in wheat were significantly decreased.     

Kinetic studies on dehydrogenation of butanol to butyraldehyde using zinc oxide as catalyst

Butyraldehyde is an important chemical for many industrial applications, especially in the production of polyvinylbutyral. A systematic study of its synthesis by catalytic dehydrogenation of butanol, using zinc oxide as catalyst has been carried out. The effect of the method of preparation of zinc oxide on its catalytic activity for the title reaction has also been studied. The optimum conditions for maximum yield have been worked out and on the basis of secondary electron micrograms the reasons for higher activity/selectivity in the case of zinc oxide calcined from zinc hydroxide is attributed to the presence of hexagonal morphology. A kinetic study for the best zinc oxide catalyst has been carried out and the rate equation has been determined.     

Nanoalumina-supported Mn2O3 as efficient adsorbent for removal of fluoride and arsenic from water: a study from lab to field

Journal of Materials Science - Water pollution with heavy metals has been a problem for the environment and human health. The cohabitation of As(III) and fluoride in groundwater has gotten...     

Synthesis and Photocatalytic Activity of Ni–Fe Layered Double Hydroxide Modified Sulphur Doped Graphitic Carbon Nitride (SGCN/Ni–Fe LDH) Photocatalyst for 2,4-Dinitrophenol Degradation

In this work, visible light-active sulphur doped graphitic carbon nitride coupled with Ni–Fe layered double hydroxide (SGCN/Ni–Fe LDH) was prepared through co-precipitation procedure using commercially available thiourea, nickel nitrate, and ferric nitrate. The surface morphology characterization showed LDH crystallite growth onto the surface of SGCN, exploiting the delocalized π-electrons of graphitic structure to attain chemical stability. The synthesized photocatalyst exhibited 98% 2,4-dinitrophenol (DNP) photodegradation within 120 min of visible light irradiations, which was surprisingly high compared to 60 and 55% obtained for bare GCN and Ni–Fe LDH samples. This photo removal efficiency could be due to suitable bandgap energy, layered graphitic and brucite Ni–Fe layered structures, and sufficient pollutant adherence to active sites provided by incorporation of S dopant into bare GCN. The characterization results obtained by cyclic voltammetry graph photoluminescence and electrochemical impedance spectra indicated minimum charge carrier recombination due to the type-II charge transfer route along with an active generation of ?O₂^? and h⁺ as dominant reactive species participating in DNP mineralization into more unaffected inorganic ions. The photocatalytic activity enhanced in an acidic medium at optimized parameters, i.e., pH 4, photocatalyst dosage 50 mg in 50 mL solution, and DNP concentration 1.0?×?10^?4 mol/dm³, due to ionic interactions between negatively charged DNP and positive intercalated structure of Ni–Fe LDH. The as-prepared photocatalyst photodegradation ability was retained after 5 catalytic cycles, confirming its environmentally-compatible usage in water treatment.

     

Ocular prosthesis.

Loss of an eye or a disfigured eye has a far-reaching impact on an individual's psyche'. Additionally it affects one's social and professional life. Cosmetic rehabilitation with custom made prosthetic devices gives such individuals professional and social acceptance and alleviates problems. This article aims at enhance awareness of the cosmetic benefits of custom designed ocular prosthesis. Ocularistry, the science of making ocular prosthesis, has undergone phenomenal growth in recent times. Ocularistry is fast evolving in India. "Ocularist" is the skilled individual involved in fabricating the ocular prosthesis.     

Angiotensin II-induced nuclear targeting of the angiotensin type 1 (AT1) receptor in brain neurons

Angiotensin II (Ang II) interaction with the neuronal AT1 receptor results in a chronic stimulation of neuromodulation that involves the expression of norepinephrine transporter (NET) and tyrosine hydroxylase (TH). In view of this unique property and the presence of putative nuclear localization signal (NLS) consensus sequence in the AT1 receptor, this study was conducted to investigate the hypothesis that Ang II would induce nuclear sequestration of this G protein-coupled receptor and that the sequestration may have implications on Ang II-induced expression of NET and TH genes. Incubation of neuronal cultures with Ang II caused a time- and dose-dependent increase in the levels of AT1 receptor immunoreactivity in the nucleus. A 6.7-fold increase was observed with 100 nM Ang II, in 15 min, that was blocked by losartan, an AT1 receptor-specific antagonist. Ang II-induced nuclear sequestration was specific for AT1 receptor, because Ang II failed to produce a similar effect on neuronal AT2 receptors. The presence of the putative NLS sequence in the cytoplasmic tail of the AT1 receptor seems to be the key in nuclear targeting because: 1) nuclear targeting was attenuated by a peptide of the AT1 receptor that contained the putative NLS sequence; and 2) Ang II failed to cause nuclear translocation of the AT2 receptor, which does not contain the putative NLS. Ang II also caused a time- and dose-dependent stimulation of P62 phosphorylation, a glycoprotein of the nuclear pore complex. A 6-fold stimulation of phosphorylation was observed with 100 nM Ang II, in 15 min, that was completely blocked by losartan and not by PD123,319, an AT2 receptor specific antagonist. Preloading of neurons with p62-pep (a peptide containing consenses of mitogen-activated protein kinase in p62) resulted in a loss of Ang II-induced p62 phosphorylation and stimulation of NET and TH messenger RNA levels. In conclusion, these data demonstrate that Ang II induces nuclear sequestration of AT1 receptor involving NLS in the AT1 receptor and p62 of the nuclear pore complex in brain neurons. A possible role of such a nuclear targeting of the AT1 receptor on chronic neuromodulatory actions of Ang II has been discussed.