Ketamine and nifedipine protect cultured cortical neurons against injurious effect of glutamate]

The effects of glutamate on cultured cortical neurons and the protective effect of ketamine and nifedipine were studied. On day 10 after plating of the cortical cells from 16-18 day-old fetal rats, the cultures were exposed to 50 mumol.L-1 glutamate and low glucose (1 g.L-1) for 10 min-24 h. The results showed that a release of lactate dehydrogenase (LDH) into the culture supernatant was observed as a function of time. The values of LDH efflux in culture medium was significantly lower than those of controls when the cells were pretreated with ketamine or nifedipine 10 min prior to addition of glutamate. More significant decrease of LDH activity in culture medium was observed when the two drugs were used in combination. These results demonstrate that the dissociated cultured cortical neurons from fetal rat are seriously damaged by glutamate. Such damage could be attenuated by ketamine and nifedipine, suggesting that ketamine and nifedipine may protect neurons from the glutamate toxicity, and the effect of combining ketamine and nifedipine was greater than either ketamine or nifedipine alone.     

PAX genes and human neural tube defects: an amino acid substitution in PAX1 in a patient with spina bifida

From studies in the mouse and from the clinical and molecular analysis of patients with type 1 Waardenburg syndrome, particular members of the PAX gene family are suspected factors in the aetiology of human neural tube defects (NTD). To investigate the role of PAX1, PAX3, PAX7, and PAX9, allelic association studies were performed in 79 sporadic and 38 familial NTD patients from the Dutch population. Sequence variation was studied by SSC analysis of the paired domain regions of the PAX1, PAX7, and PAX9 genes and of the complete PAX3 gene. In one patient with spina bifida, a mutation in the PAX1 gene was detected changing the conserved amino acid Gln to His at position 42 in the paired domain of the protein. The mutation was inherited through the maternal line from the unaffected grandmother and was not detected in 300 controls. In the PAX3 gene, variation was detected at several sites including a Thr/Lys amino acid substitution in exon 6. All alleles were present among patients and controls in about the same frequencies. However, an increased frequency of the rare allele of a silent polymorphism in exon 2 was found in NTD patients, but no significant association was observed (p = 0.06). No sequence variation was observed in the paired domain of the PAX7 and PAX9 genes. Our findings so far do not support a major role of the PAX genes examined in the aetiology of NTD. However, the detection of a mutation in PAX1 suggests that, in principle, this gene can act as a risk factor for human NTD.     

Fibromuscular dysplasia associated with intracranial giant aneurysm: report of a case

Although the correlation between fibromuscular dysplasia (FMD) and intracranial aneurysm is well established, the combination of FMD with a giant aneurysm is rare. This paper reports a patient with extracranial FMD associated with a giant intracavernous aneurysm compromising the trigeminal and abducens nerve. A review of the literature uncovered only four documented cases of FMD with concurrent giant intracranial aneurysms. The present case adds further weight to the argument for including FMD in the differential diagnosis list when confronted with a patient with a giant intracranial aneurysm. Absence of adequate collaterals in this patient eliminated ligation as a treatment strategy for the aneurysm.     

Polymerization of fluoroacrylate and guar gum copolymer as a new pretreatment paste for ink‐jet printing of polyester

A novel pretreatment paste containing fluoroacrylate copolymer and modified Guar Gum was carried out on the polyester fabric to provide partial water repellency and printability after inkjet printed with water‐based disperse dye inks. The stable fluorinated pastes were prepared via miniemulsion polymerization of fluoroalkyl acrylates, styrene, 2‐ethylhexyl acrylate, and modified guar gum in the presence of AIBN as initiator, CTAB and polyoxyethylene polyaryl ether as surfactants under suitable reaction conditions. In the analysis of monomer conversion and particle size, the highest polymerization rate with smallest particle size was obtained with increasing concentration of surfactants and initiator but the decreasing degree of substitution of guar gum to imply stronger interactions between fluoroacrylate monomers, hydroxyl groups of modified guar gum and EO units of nonionic surfactants. The 30% of stock fluorinated paste with urea concentration of 6% provided the prints with highest K/S value, satisfactory edge acuity and least color difference between front and back sides of the fabric to show more transparency. The rating 80 of water repellency tested on the best treated polyester fabric demonstrated stain proof properties after sprayed with water and dried. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Aqueous Foam Stabilized by Hydrophobic SiO2 Nanoparticles using Mixed Anionic Surfactant Systems under High-Salinity Brine Condition

A primary concern of surfactant-assisted foams in enhanced oil recovery (EOR) is the stability of the foams. In recent studies, foam stability has been successfully improved by the use of nanoparticles (NP). The adhesion energy of the NP is larger than the adsorbed surfactant molecules at the air–water interface, leading to a steric barrier to mitigate foam-film ruptures and liquid-foam coalescence. In this study, the partially hydrophobic SiO₂ nanoparticles (SiO₂-NP) were introduced to anionic mixed-surfactant systems to investigate their potential for improving the foamability and stability. An appropriate ratio of internal olefin sulfonate (C_15-18 IOS) and sodium polyethylene glycol monohexadecyl ether sulfate (C₃₂H₆₆Na₂O₅S) was selected to avoid the formation of undesirable effects such as precipitation and phase separation under high-salt conditions. The effects of the NP-stabilized foams were investigated through a static foam column experiment. The surface tension, zeta potential, bubble size, and bubble size distribution were observed. The stability of the static foam in a column test was evaluated by co-injecting the NP-surfactant mixture with air gas. The results indicate that the foam stability depends on the dispersion of NP in the bulk phase and at the water–air interface. A correlation was observed in the NP-stabilized foam that stability increased with increasing negative zeta potential values (−54.2 mv). This result also corresponds to the smallest bubble size (214 μm in diameter) and uniform size distribution pattern. The findings from this study provide insights into the viability of creating NP-surfactant interactions in surfactant-stabilized foams for oil field applications.     

Analytical Water Shortage Probabilities and Distributions of Various Lead Times for a Water Supply Reservoir

Water Resources Management - Reducing the negative impacts of water shortages is the primary concern of water supply reservoir operation. This study aims to propose a theoretical framework of water...