Abstract Candida glabrata infections are responsible for deaths of people globally. Fluconazole is known to be less effective against C. glabrata, which developed many strategies to evade being destroyed by fluconazole. To achieve enhanced efficacy of fluconazole against C. glabrata, the interaction of fluconazole with sodium bicarbonate was investigated using the CLSI guidelines. The efficacy of fluconazole alone and in combination with sodium bicarbonate was evaluated using the time-kill and phospholipase production assays. Eventually, the expression of PLB was assessed using semi-quantitative RT-PCR to investigate the inhibitory properties of fluconazole alone and in combination with sodium bicarbonate against C. glabrata. The fluconazole/sodium bicarbonate combination displayed synergistic and antagonistic effects (FICI= 0.375-4.25). In C. glabrata ATCC, SN 152, and SN 164, the fluconazole/sodium bicarbonate combination exhibited a significant fungicidal activity (p< 0.05) but antagonistic effect in the case of SN 283. With exception of SN 283, a significant reduction was noted in phospholipase production in clinical isolates of C. glabrata treated with fluconazole/sodium bicarbonate combination. The PLB was down-regulated significantly by 0.168-0.515 fold in C. glabrata treated with fluconazole/sodium bicarbonate. The results suggested fluconazole/sodium bicarbonate to have a potential synergistic interaction in C. glabrata, and the underlying mechanism may be associated with phospholipase gene.

In the present work, a novel, simple, and efficient method for the determination of silver in natural water samples was developed. The method is based on the extraction of silver with coacervate made up of decanoic acid reverse micelles and the subsequent determination by flame atomic absorption spectrometry (FAAS). Dithizone was used as a chelating agent. To obtain the best extraction results, some experimental parameters (such as coacervate composition, pH, concentration of chelating agent, and ionic strength) affecting the extraction efficiency were investigated and optimized. Under optimum conditions, the calibration curve was linear in the concentration range of 5-200 µg L-1, with the correlation coefficient (r) equal to 0.995. The limit of detection and the enrichment factor were 1.6 µg L-1 and 15, respectively. The method was successfully applied to the analysis of silver in natural water samples.

The determination of the difficulty factor in knowledge work can be important for improving the performance of knowledge workers. In this article a regression model for investigating the difficulty of knowledge based activities (KBAs) is proposed. Four factors are considered in the model: Uncertainty, Variability of information, Amount of information and Level of skill and expertise. An empirical study based on 119 jobs from three different groups of knowledge workers (i.e. managerial, professional and clerical) shows that there are significant differences between the difficulty of the KBAs in managerial, clerical and professional jobs, and that managerial KBAs are more difficult than the KBAs of the other two groups. Furthermore, regression models indicate that Level of skill and expertise is the most influential factor in the difficulty of the KBAs in each of the three groups.

In this paper the uniform nanopowders of La0.5Ca0.5CoO3-δ and La0.5Ca0.5NiO3-δ (LCCO and LCNO) were synthesized from nitrates of the constituent metal ion, citric acid (CA), and ethylene glycol (EG) by the combined citrate-ethylene glycol (EG) method. These nanopowders were also characterized by differential thermal analysis (DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM), SEM-EDX analysis and Brunauer-Emmett-Teller (BET) method XRD results show that single perovskite phase was completely formed after calcination at 750 °C. Fourier transform infrared (FTIR) spectra were measured for the xerogels and powder samples after calcination. In addition, the TEM images show that the average particle size of nanoparticles is approximately 25-32 nm in diameter. The ultraviolet (UV) spectrum was used to calculate the absorption coefficient (a) as a function of photon energy (hv) and the obtained results indicate that the optical band gap energy (Eg) for LCNO sample is smaller than that of LCCO. Finally, the temperature dependence of the specific resistivity of LCCO and LCNO sintered at 1100 °C was compared and revealed that the resistivity of both compounds decreases exponentially by increasing the temperature.