The increased prevalence of hypervirulent ribotype 027 Clostridium difficile requires rapid identification of iso lates in ordertoimplementtimelyinfectioncontrol strategies. Highresolution melt(HRM) analysisof PCRprod ucts can identify strain variation amongst genera of bacteria. The intergenic (16S–23S rDNA) spacer region contains sequenceregionsconserved withingeneraandothersequenceregionvariablesbetweenspecieswithin genera. Wewished toinvestigate whether HRM analysis of PCR ribotyping products could identify ribotype 027 C. difficile. Ribotyping was performed on 93 clinical isolates and five control strains and band patterns were ana lysedusingGelComparII(AppliedMaths,USA).Real-timePCRusingribotypingprimerswasperformedandnor malised melt curves were generated. The HRM data was then imported into ScreenClust software (QIAGEN) to generate principal component analysis graphs depicting clustered relationships of strains. Ribotyping produced clear PCR bands for 88/98 isolates tested. Dendrograms generated by GelCompar showed a diversity of ribotype patterns amongst these 88 isolates with 18 groups identified with 70% homology. One clinical isolate showed 100%homologywiththecontrol027strains. ScreenClustanalysisofthe same88HRMresultsshowedclustering of isolates, with 027 strains identifiable as a unique cluster. HRM analysis correctly identified the control 027 stains and the clinical isolate shown to be 027. HRM combined with ScreenClust analysis of real-time PCR prod ucts of the 16S–23S rDNA spacer region successfully identified ribotype 027 strains. For infection control pur poses this was achieved within 2–3 h of colony isolation.

NAD(P)H:quinone oxidoreductase (NQO1)-mediated detoxification of quinones plays a critical role in cancer prevention. Heavy metals such as mercury (Hg(2+)) alter the carcinogenicity of aryl hydrocarbon receptor ligands, mainly by modifying various xenobiotic-metabolizing enzymes such as NQO1. Therefore, we examined the effect of Hg(2+) on the expression of NQO1 in human hepatoma HepG2 cells. For this purpose HepG2 cells were incubated with various concentrations of Hg(2+) (2.5, 5, and 10μM) in the presence and absence of two NQO1 inducers, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and isothiocyanate sulforaphane (SUL), as bifunctional and monofunctional inducers, respectively. Analysis of the time-dependent effect of Hg(2+) revealed that Hg(2+) increased the expression of NQO1 mRNA in a time-dependent manner. In addition, Hg(2+) increased NQO1 at the mRNA, protein, and activity levels in the presence and absence of both NQO1 inducers, TCDD and SUL, which coincided with increased nuclear accumulation of Nrf2 protein. Investigating the effect of Hg(2+) at the transcriptional level revealed that Hg(2+) significantly induced the antioxidant-responsive element-dependent luciferase reporter gene expression in the absence and the presence of both NQO1 inducers. NQO1 mRNA and protein decay experiments revealed a lack of posttranscriptional and posttranslational mechanisms. Transfecting HepG2 cells with siRNA for Nrf2 significantly decreased the Hg(2+)-mediated induction of NQO1 mRNA and catalytic activity by approximately 90%. In conclusion, we demonstrated that Hg(2+) regulates the expression of the NQO1 gene through a transcriptional mechanism in human hepatoma HepG2 cells. In addition, Nrf2 is involved in the modulation of NQO1 by Hg(2+).

Utility of Nitriles in Organic Synthesis: Synthesis of Poly-Functionaly Substituted Pyridones and Isoquinoline Derivatives. Alex. J. Pharm. Sci.

Aryl hydrocarbon receptor (AhR) ligands such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and metals, such as mercury (Hg(2+)), are environmental co-contaminants and their molecular interaction may disrupt the coordinated regulation of the carcinogen-activating enzyme cytochrome P450 1A1 (CYP1A1). Therefore, we examined the effect of co-exposure to Hg(2+) and TCDD on the expression of the CYP1A1 in HepG2 cells. Our results showed that Hg(2+) significantly inhibited the TCDD-mediated induction of CYP1A1 at the mRNA, protein, and catalytic activity levels. At the transcriptional level, co-exposure to Hg(2+) and TCDD significantly decreased the TCDD-mediated induction of AhR-dependent luciferase reporter gene expression. Moreover, Hg(2+) did not affect CYP1A1 mRNA stability, while decreasing its protein half-life, suggesting the involvement of a posttranslational mechanism. Importantly, Hg(2+) increased the expression of heme oxygenase-1 (HO-1), a rate limiting enzyme in heme degradation, which coincided with further decrease in the CYP1A1 catalytic activity levels. Upon using a competitive HO-1 inhibitor, tin mesoporphyrin, heme precursor, hemin, or transfecting the HepG2 cells with siRNA for HO-1 there was a partial restoration of the inhibition of TCDD-mediated induction of CYP1A1 catalytic activity. In conclusion, we demonstrate that Hg(2+) down-regulates the expression of CYP1A1 at the transcriptional and posttranslational levels in HepG2 cells. In addition, HO-1 is involved in the modulation of CYP1A1 at the posttranslational level.

The monolingual/bilingual dictionary use dichotomy has recently gained more spotlight than before, and this dichotomy has turned back to reassess the usefulness of each type in terms of vocabulary knowledge and acquisition. Although EFL (English as a foreign language) learners perceive dictionaries as inevitable references for vocabulary knowledge and linguistic consultation and almost all (learners and teachers) consider dictionaries ‘absolutely essential’ in the learning and teaching profession (Christianson, 1997; Walz, 1990; McAlpine and Myles, 2003), the usefulness of dictionaries tends to be dependent upon the type of dictionary being consulted (Laufer and Hadar, 1997; Hulstijn, 1993; Knight, 1994). Within this heated debate and abounding controversies over the usefulness of dictionary, the usability of dictionary and dictionary usefulness (Laufer and Kimmel, 1997) “do not necessarily go hand in hand” (p. 362), and Arab FL (Foreign language)  learners’ perspectives towards dictionary types problems and users’ dictionary type preferences are not yet unearthed (Al-Ajmi, 2002). Moreover, within the recent emphasis for dictionary skills (Scholfield, 1982, Laufer and Hadar, 1997; Laufer and Kimmel, 1997), it is reported that Arab learners are not dictionary competent or skilled dictionary users and do lack the necessary skills (Aly, 2004). Within this framework, this qualitative study aims at arriving at a deeper understanding of the problems of dictionary use, either bilingual or monolingual, as faced by Libyan Arab learners for general dictionary use purposes among postgraduate master students at UUM(Univeristi Utara Malaysia). 

Positioning systems are one of the key elements required by location-based services (LBS). As global positioning system (GPS) was never intended for indoor environments, indoor positioning systems based on wireless local area networks (WLAN) have been proposed as a viable solution. RADAR algorithm is one of the famous indoor positioning techniques. It uses a database of predetermined fingerprints for selected locations to estimate the location of a mobile user in the signal space. Another new proposed algorithm named the Enhanced Fingerprint (EFP) uses the same principle as RADAR algorithm but with more than one fingerprint per location. In this paper we investigated the location fingerprint based algorithms by taking RADAR and EFP with more details. We evaluated these two algorithms in terms of accuracy, reliability and computation time. Experiment results show that the EFP algorithm gains 1.82 m of accuracy over RADAR algorithm, while the last one saves 75% of computation time. We found that EFP algorithm is more consistent with varying number of training samples.