All-perylene-derivative for white light emitting diodes.

An organic-based bright white light emitting compound, namely Tb(H3PTC)3 [H4PTC = perylene-3,4,9,10-tetracarboxylic acid], able to be used as part of a white diode and as a part of a RGB system that can withstand high temperatures (∼700 K), is developed using perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) and terbium(iii) nitrate pentahydrate as precursors by hydrothermal synthesis. Using PTCDA as the red emitter and the new derivative of it, Tb(H3PTC)3, as the blue-green emitter, along with a common deep blue LED can form a RGB system for display technologies, around room temperature. Temperature-dependent photoluminescence properties of the Tb(H3PTC)3 compound are also investigated for the involved excitonic-emission processes and the respective recombination lifetimes. The terbium(iii) complex was prepared using a procedure that is reproducible, easily modifiable, inexpensive, and environmentally friendly, opening new pathways for its large-scale applications. Unlike PTCDA, Tb(H3PTC)3 has been shown to be soluble in N-methyl-2-pyrrolidone (NMP) as well as in dilute aqueous solutions of this organic solvent in a straightforward procedure. The light emission properties are intimately correlated with the molecular structure and electronic properties of Tb(H3PTC)3 elucidated by experimental results of X-ray Absorption Near Edge Spectroscopy (XANES), Extended X-ray Absorption Fine Structure (EXAFS) and Density Functional Theory (DFT) calculations. A bright fluorescence yield is attained with a small amount of material either in solution or in solid form showing its potential to be used in state-of-the-art organic optoelectronic devices.

Derivation, characterization and differentiation of buffalo (Bubalus bubalis) amniotic fluid derived stem cells.

Amniotic fluid cells (AFCs) are obtained from amnion for pre-natal analysis and can be cultured in vitro. Heterogeneous amniotic fluid (AF) contains various cell types, and it is believed that some of these cells possess the stem cell properties. The aim of this study was to characterize these cells by phenotypical and genotypical means in buffalo. The differentiation potential of amniotic fluid stem (AFS) cells was carried out by converting these cells into neurons. The AFCs were cultured without feeder cells in DMEM containing 16% foetal bovine serum, 1% penicillin/streptomycin and 1%l-glutamine in 5% CO(2) at 38.5 ± 0.5 °C in a CO(2) incubator. After 6 days of culture, different types of cells viz., star shaped (62.7%), spherical without nucleus (1.9%), spherical with nucleus (26.4%), pentagonal (0.4%) and free floating/rounded cells (8.3%) were observed. Most of the cells started anchorage-dependent growth after day 7 of the culture. Expression of Oct-4, Sox-2, Nanog, alkaline phosphatase, 18s rRNA, stem cell factor, cyclin A, Nestin and FGF-5 was observed from the AFS cells in different passages with PCR amplicon of 314, 277, 317, 180, 162, 216, 421, 307 and 210 bp, respectively. During the differentiation step, at day 6, neuron-like cells could be clearly identified and confirmed with Nestin-specific RT-PCR. The cells were found to have a normal karyotype at different passages. These results may contribute towards establishing non-embryonic pluripotent stem cells for various therapeutic and reproductive biotechnological applications in the species.

Tannase Production by Penicillium Atramentosum KM under SSF and its Applications in Wine Clarification and Tea Cream Solubilization.

Tannin acyl hydrolase commonly known as tannase is an industrially important enzyme having a wide range of applications, so there is always a scope for novel tannase with better characteristics. A newly isolated tannase-yielding fungal strain identified as Penicillium atramentosum KM was used for tannase production under solid-state fermentation (SSF) using different agro residues like amla (Phyllanthus emblica), ber (Zyzyphus mauritiana), jamun (Syzygium cumini), Jamoa (Eugenia cuspidate) and keekar (Acacia nilotica) leaves. Among these substrates, maximal extracellular tannase production i.e. 170.75 U/gds and 165.56 U/gds was obtained with jamun and keekar leaves respectively at 28ºC after 96 h. A substrate to distilled water ratio of 1:2 (w/v) was found to be the best for tannase production. Supplementation of sodium nitrate (NaNO3) as nitrogen source had enhanced tannase production both in jamun and keekar leaves. Applications of the enzyme were studied in wine clarification and tea cream solubilization. It resulted in 38.05% reduction of tannic acid content in case of jamun wine, 43.59% reduction in case of grape wine and 74% reduction in the tea extract after 3 h at 35°C.

Reproductive biotechniques in buffaloes (Bubalus bubalis): status, prospects and challenges.

The swamp buffalo holds tremendous potential in the livestock sector in Asian and Mediterranean countries. Current needs are the faster multiplication of superior genotypes and the conservation of endangered buffalo breeds. Recent advances in assisted reproductive technologies, including in vitro embryo production methodologies, offer enormous opportunities to not only improve productivity, but also to use buffaloes to produce novel products for applications to human health and nutrition. The use of molecular genomics will undoubtedly advance these technologies for their large-scale application and resolve the key problems currently associated with advanced reproductive techniques, such as animal cloning, stem cell technology and transgenesis. Preliminary success in the application of modern reproductive technologies warrants further research at the cellular and molecular levels before their commercial exploitation in buffalo breeding programmes.

Effect of type of cryoprotectant on morphology and developmental competence of in vitro-matured buffalo (Bubalus bubalis) oocytes subjected to slow freezing or vitrification.

The present study examined the effects of different cryoprotectants on morphology and developmental competence of in vitro-matured buffalo oocytes after slow freezing or vitrification. After slow freezing in dimethyl sulfoxide (DMSO), ethylene glycol (EG) or 1,2-propanediol (PROH), at 1.0 or 1.5 m each, the proportion of morphologically normal oocytes recovered was significantly higher (P < 0.05) with 1.5 than 1.0 m for all cryoprotectants and was highest (P < 0.05) for 1.5 m DMSO. Following vitrification, the percentage of morphologically normal oocytes recovered was lower (P < 0.01) for 40% EG than for 40% DMSO, 20% EG + 20% DMSO or 20% EG + 20% PROH. The most common damage, irrespective of the cryopreservation method, was loss of cumulus mass. The cleavage rate and the proportion of vitrified-warmed oocytes that developed to morulae/blastocysts were significantly higher (P < 0.01) for 20% EG + 20% DMSO than for the other groups. A higher proportion of oocytes developed to morulae (11.5% v. 4.3%) or blastocysts (5.4% v. 0.6%) after vitrification in 20% EG + 20% DMSO than after slow freezing in 1.5 m DMSO. In conclusion, vitrification was more effective than slow freezing for the cryopreservation of in vitro-matured buffalo oocytes.

Effect of slow freezing on morphology and developmental competence of buffalo (Bubalus bubalis) immature oocytes.

The present study was conducted to evaluate the effects of three cryoprotectants, dimethyl sulphoxide (DMSO), ethylene glycol (EG) and 1,2-propanediol (PROH), each used at two concentrations (1.0 and 1.5 M) on the morphology, maturation rate and developmental capacity of usable quality immature buffalo oocytes subjected to slow freezing. The addition of the cryoprotectant before freezing and its dilution after thawing were carried out in a two- (for 1.0 M) or three-step manner (for 1.5 M). The incidence of damage was found to be significantly higher (P<0.05) with the lower concentration of 1.0 M, compared to that with 1.5 M for all the three cryoprotectants examined. The proportion of immature oocytes recovered in a morphologically normal state was significantly higher (P<0.05) for DMSO than those for EG or PROH at both 1.0 and 1.5 M concentrations. Among the six combinations evaluated, that of DMSO at 1.5 M concentration was found to be superior to others. Irrespective of the type or concentration of the cryoprotectant, partial or complete loss of the cumulus mass was the most prevalent damage. Following in vitro maturation, the nuclear maturation rate was significantly higher (P<0.05) for DMSO than those for EG or PROH at both 1.0 and 1.5 M concentrations. When the in vitro matured oocytes were subjected to in vitro fertilization after slow freezing, using 1.5 M DMSO as cryoprotectant, 4.5% and 0.6% of them were able to develop to morulae and blastocysts, respectively, on Day 9 post insemination, compared to 19.2% and 10.6%, respectively, for the controls. In conclusion, DMSO was more effective than EG or PROH for the slow freezing of immature buffalo oocytes and blastocysts could be produced from immature buffalo oocytes subjected to slow freezing in 1.5 M DMSO.

Development of a pronuclear DNA microinjection technique for production of green fluorescent protein-expressing bubaline (Bubalus bubalis) embryos.

Oocytes from abattoir-derived bubaline (Bubalus bubalis) ovaries were subjected to IVM and IVF; the objective was to develop a pronuclear DNA microinjection technique to produce embryos expressing green fluorescent protein (GFP). The largest proportion (61.2%) of zygotes in which one (1 PN) or two pronuclei (2 PN) were visible was when centrifugation (14,000 x g for 15 min) was done 16 h after insemination. Centrifugation had no adverse effects on cleavage rate, development to morulae/blastocysts, and total cell number of embryos. Piercing the pronuclear but not the plasma membrane reduced (P<0.05) cleavage rate (44.0% vs. 51.0%), without affecting subsequent development. Following microinjection of a GFP-DNA construct, cleavage rate (55.9, 38.9, and 30.9%) and proportion of cleaved embryos that developed to morulae (39.9, 25.6, and 15.5%) and blastocyst stages (22.4, 13.4, and 2.8%) were higher (P<0.05) for non-injected controls than for those injected with buffer alone, which, in turn, were higher (P<0.05) than for those injected with buffer containing 5 microg/mL DNA. The cleavage rate (39.2% vs. 34.8%) and proportion of cleaved embryos that developed to morulae/blastocysts (37.5% vs. 10.9%) were higher (P<0.05) for microinjected zygotes with 2 PN than for those with 1 PN. The cleavage rate and the proportion of cleaved embryos that developed to morulae and blastocysts were higher (P<0.05) following culture of microinjected zygotes in mCR2aa medium (40.7, 32.7, and 9.1%, respectively) compared to those for mSOFaa (33.3, 26.0, and 6.5%, respectively) or after culture in TCM-199+co-culture with buffalo oviductal epithelial cells (31.2, 25.0, and 4.5%, respectively). The proportion of embryos expressing GFP was higher (P<0.01) for 2 PN than for 1 PN zygotes (15.9% vs. 13.7%). Thirty-five embryos expressed GFP; the proportion of mosaic embryos (62.8%) was higher (P<0.01) than of embryos in which all blastomeres expressed GFP (37.2%); eight and two of those embryos developed to the morula and blastocyst stages, respectively.

Dechlorination of DDT mediated by bimetallic systems.

DDT dechlorination efficiencies of bimetallic systems, namely, Mg0-Zn, Mg0-Ni, and Mg0-Co were compared. All the systems transformed DDT with efficiencies exceeding 98% within 24 h. Based on GC-ECD and GC-MS analyses a step-wise and sequential dechlorination of DDT by Mg0-Zn system in 1:1 water acetone phase via 1,1 dichloro, 2,2- bis (p-chlorophenyl) ethane (DDD), 1, chloro, 2,2 bis (p-chlorophenyl) ethane (DDMS) to 2,2 bis (p-chlorophenyl) ethane (DDNS) was noted. Accumulation of DDNS as the end product indicates that all three alkyl chlorine atoms of DDT were removed by Mg0-Zn system. Mg0-Co also showed almost complete removal of DDT in water-acetone phase that was accompanied by the accumulation of DDD followed by a decline in its concentration as a function of time. On the other hand, Mg0-Ni system exhibited inefficient removal of DDT in water-acetone phase. In pure acetone phase, Mg0-Co system and Mg0-Ni dechlorinated DDT with the accumulation of DDE and DDMU as end products following 24 h of reaction. The presence of surfactants or organic solvents is required to ensure solubilization of DDT. Also addition of acid is essential to provide sufficient protons for efficient reductive dechlorination via hydrogenation. Advantage of Mg0 based dehalogenation reactions is that they occur at high rates under ambient temperatures, and pressure and oxygen need not be excluded in the reaction phase. Our studies revealed that Mg0-Zn is the best option among all tested systems due to its high reactivity and low cost, and may be used to treat DDT contaminated water.

Is there a case for haemorheological screening in the haemocompatibility testing of materials?

Bio-interactions between a material and blood govern the compatibility of the material with the human body and, therefore, the single most important requirement for the blood interfacing implants/devices is haemocompatibility. The decisive events which control haemocompatibility occur at the molecular level and affect the various subphases of blood rheology. This effect on the already complex human blood rheology can be used to our advantage in the screening of blood-contacting materials. An attempt has been made in the present work to evaluate the haemocompatibility of materials based on changes in microrheological parameters of human blood. Samples of materials of equal surface area known to be haemocompatible (medical grade silicon, polyvinyl chloride from blood bags) and materials known to be extremely haemo-incompatible (pyrex glass, copper, cotton fabric, all commercial grade) were incubated at 37.4 degrees C in freshly drawn anticoagulated whole human blood, and changes in the haemorheological parameters (whole blood, plasma viscosity, intrinsic viscosity of red cells, platelet aggregation, albumin fibrinogen ratio) have been evaluated. The results of the study show that alterations in the haemorheological parameters are reliable indicators to the compatibility/incompatibility characteristics of well-known substances and that there is a case for haemorheological screening of biomaterials in the overall framework of haemocompatibility tests.

GABA/BZ-and NMDA-receptor interaction in digoxin-induced convulsions in rats.

Digoxin (7.5 micrograms icv) induced 'pop-corn' type of convulsions and 100% mortality. The GABA-ergic agents produced varying degree of protection against digoxin-induced neurotoxicity. Diazepam (4 mg/kg) offered significant protection whereas pentobarbital (5 mg/kg) and baclofen (5 mg/kg) markedly reduced per cent mortality, but ethanol (2 g/kg), progabide (50 mg/kg) and muscimol (0.5 mg/kg) as well as GABA (50 mg/kg) could not offer significant protection in doses used. GABA-ergic agonists; GABA, baclofen, diazepam and pentobarbital when administered along with MK-801 (0.5 mg/kg) a non-competitive NMDA antagonist, a potentiation of anticonvulsant action of MK-801 was observed. MK-801 showed potent anticonvulsant profile in dose range (0.25-1 mg/kg) studied. A synergistic influence of Mg2+ and K+ ions on NMDA receptor antagonism was also observed. A role of GABA-ergic facilitation and NMDA antagonism as a potential anticonvulsant approach in digoxin-induced convulsions in rats has been suggested.

Paediatric dentistry in the new millennium: 4. Cost-effective restorative techniques for primary molars.

In the fourth article in this series the techniques for carrying out pulp therapy and stainless steel restoration in primary molars are discussed. Early pulp involvement in primary molars means that pulp therapy and the use of appropriate coronal restoration, such as stainless steel crowns, are indispensable if repetitive restoration of primary molars is to be avoided. These techniques themselves are not difficult to carry out once the child's co-operation is established and should be well within the capability of any dentist with an interest in the dental care of children.

Isolation and characterization of embryonic stem cell-like cells from in vitro-produced buffalo (Bubalus bubalis) embryos.

This study was carried out to isolate and characterize buffalo embryonic stem (ES) cell-like cells from in vitro-produced embryos. Inner cell mass (ICM) cells were isolated either mechanically or by enzymatic digestion from 120 blastocysts whereas 28 morulae were used for the isolation of blastomeres mechanically. The ICM cells/ blastomeres were cultured on mitomycin-C-treated feeder layer. Primary cell colony formation was higher (P < 0.05) for hatched blastocysts (73.1%, 30/41) than that for early/expanded blastocysts (25.3%, 20/79). However, no primary cell colonies were formed when blastomeres obtained from morulae were cultured. Primary colonies were formed in 14.1% (12/85) of intact blastocyst culture, which was significantly lower (P < 0.05) than that of 41.6% for ICM culture. These colonies were separated by enzymatic or mechanical disaggregation. Using mechanical disaggregation method, the cells remained undifferentiated and two buffalo ES cell-like cell lines (bES1, bES2) continued to grow in culture up to eight passages. However, disassociation through enzymatic method resulted in differentiation. Undifferentiated cells exhibited stem cell morphological features, normal chromosomal morphology, and expressed specific markers such as alkaline phosphatase (AP) and Oct-4. Cells formed embryoid bodies (EBs) in suspension culture; extended culture of EBs resulted in formation of cystic EBs. Following prolonged in vitro culture, these cells differentiated into several types of cells including neuron-like and epithelium-like cells. Furthermore, the vitrified-thawed ES cell-like cells also exhibited typical stem cell characteristics. In conclusion, buffalo ES cell-like cells could be isolated from in vitro-produced blastocysts and maintained in vitro for prolonged periods of time.

Tannase production by Penicillium atramentosum KM under SSF and its applications in wine clarification and tea cream solubilization

Tannin acyl hydrolase commonly known as tannase is an industrially important enzyme having a wide range of applications, so there is always a scope for novel tannase with better characteristics. A newly isolated tannase-yielding fungal strain identified as Penicillium atramentosum KM was used for tannase production under solid-state fermentation (SSF) using different agro residues like amla (Phyllanthus emblica), ber (Zyzyphus mauritiana), jamun (Syzygium cumini), Jamoa (Eugenia cuspidate) and keekar (Acacia nilotica) leaves. Among these substrates, maximal extracellular tannase production i.e. 170.75 U/gds and 165.56 U/gds was obtained with jamun and keekar leaves respectively at 28ºC after 96 h. A substrate to distilled water ratio of 1:2 (w/v) was found to be the best for tannase production. Supplementation of sodium nitrate (NaNO3) as nitrogen source had enhanced tannase production both in jamun and keekar leaves. Applications of the enzyme were studied in wine clarification and tea cream solubilization. It resulted in 38.05 percent reduction of tannic acid content in case of jamun wine, 43.59 percent reduction in case of grape wine and 74 percent reduction in the tea extract after 3 h at 35ºC.

Cross-flow microfiltration of blood through an extracorporeal device: a study in parameterization.

This paper develops a new approach for the general description of membrane plasma separator performance by using dimensional analysis. Experiments involved cross-flow microfiltration of goats' blood across flatsheet polyvinylidene fluoride durapore membranes of pore size 0.65, 0.45 and 0.22 microns in a thin-channel device. Certain non-dimensional numbers are evolved which represent the grouping of relevant filtration parameters and which contribute to the global characterization of membrane-based plasmapheresis devices.

A study of antidepressant activity of some indole alkylamines.

The antidepressant characteristics of three indole alkylamines were investigated and compared with phenelzine and imipramine by utilising specific pharmacological tools like reserpine, amphetamine, tryptamine and tetrabenazine for determining their possible mechanism of action. Amongst the three indole compounds investigated, indole-3-(2-aminopropyl)-acetate (U-14 164E), indole-3(2-aminobutyl)-d-acetate (u-17 312E) and beta-phenethylhydrazine (phenelzine) produced complete antagonism to reserpine induced sedation, hypothermia as well as facilitation of convulsive seizures. Some of these features suggest that MAO inhibition might be a common mechanism of action of these indoles. The potentiation of CNS effects of tryptamine by these compounds is an outstanding feature of MAO inhibitors, while imipramine is ineffective. Qualitative differences between these indoles and imipramine are evident in the tetrabenazine test. The potentiation of amphetamine induced motor excitation and pentobarbitone narcosis has been explained.

Exploiting temperature dependence to improve selectivity in membrane-based plasmapheresis.

Temperature effects on cross-flow membrane plasmapheresis have been investigated with the help of hydrophillic polyvinylidene fluoride (PVDF) Durapore membranes of pore size 0.65 micron and an effective filtration area 30 cm2, using a thin-channel device (Minitan-S, Millipore Inc., U.S.A.) and goat's blood as the working fluid. The filtration and sieving properties have been characterized by evaluating normal saline (0.9 g%) flux and the sieving coefficients of albumin, immunoglobulins, and fibrinogen respectively. Runs were performed at 10 +/- 1, 20 +/- 1, 30 +/- 1 and 40 +/- 1 degree C, the various filtration parameters were measured and samples of the feed and permeate were collected during steady state. It is seen that the "effective" pore size increases with temperature increase thereby increasing flux, sieving and fouling. Exploiting temperature effects can possibly help modify the sieving spectrum in membrane-based plasmapheresis.