To the Editor: West Nile virus (WNV) is a mosquitoborne flavivirus. Approximately 80% of human infections are asymptomatic, 10%–20% are characterized by an acute febrile illness, and <1% by involvement of the central nervous system (West Nile neuroinvasive disease). Sporadic human cases and small outbreaks of West Nile fever were reported in Europe until the mid-1990s, when the first large outbreak occurred in Romania in 1996.\ud \ud Since then, and especially in recent years, sporadic human cases and outbreaks have been reported in other countries in Europe and neighboring countries on the Balkan Peninsula. A large outbreak of WNV lineage 2 infection occurred in Greece in 2010. Outbreaks have also been reported in other countries in Europe, which showed spread of WNV lineage 2. Some probable cases of West Nile fever were reported to the Bulgarian Ministry of Health on the basic of serologic test results.\ud \ud We report a case of fatal West Nile neuroinvasive disease in a man in Bulgaria. This case was confirmed by detection of specific antibodies against WNV and sequencing of the full virus genome

In this study, the sorption of Cu(II) ions in aqueous solutions of Zeolite NaA by performing batch kinetic sorption experiments. The equilibrium kinetic data were analyzed using the pseudo-second-order kinetic model. A comparison was made of the linear least-squares method and nonlinear method of the widely used pseudo-second-order kinetic model for the sorption of Cu(II) ions of Zeolite . Four pseudo-second-order kinetic linear equations are discussed. Kinetic parameters obtained from the four kinetic linear equations using the linear method differed but they were the same when using the non-linear method. Kinetic parameters obtained from four kinetic linear equations using the linear method differed. Equation type 1 pseudo-second-order kinetic model very well represented the kinetic of the adsorption Cu(II) ions by Zeolite NaA. Equation type 4 exhibited the worst fit. Present investigation showed that the non-linear method may be a better way to determine the kinetic parameters.

The aim of this study was to obtain synthetic corundum monocrystals, called star ruby and star sapphire, using the Verneuil flame fusion process. The corundum monocrystals are known to possess an unusual complex of properties which determine their increasing application in different areas of jewelry and technology The optimal temperature-time parameters during obtaining the starting mixtures which contribute to the synthesis of high quality corundum monocrystals were established. The corundum monocrystals obtained are equivalent to the natural gemstones -rubies and sapphires.

A lightweight inorganic polymer is obtained using ash from thermal power plants, metakaolinite and lightweight aggregate. This inorganic material is activated using small amounts of sodium hydroxide and sodium silicate solution. Processing parameters and various curing conditions, such as curing temperature, curing time and moisture, are investigated. Compressive strength, rate of water absorption and density of each sample were measured.

A lightweight inorganic polymer is obtained using by ash from thermal power plants and lightweight aggregate from perlite . This inorganic material is activated using small amounts of sodium hydroxide and sodium silicate solution. In addition, porosity and water absorption were determined. Results showed that the lightweight geopolymer blocks with satisfactory strength and density could be made. The 28-day compressive strength of 5.2–13.8 MPa, density of 1075–1345 kg/m3, water absorption of 10–28% and porosity of 15–32% obtained. It can be used as lightweight geopolymer concrete for partition walls.