effect of noise on human performance: a clinical trial

Noise is defined as unwanted or meaningless sound that apart from auditory adverse health effects may distract attention from cues that are important for task performance. Human performance is influenced by many job-related factors and workplace conditions including noise level. To study the effect of noise on human performance. The participants included 40 healthy male university students. The experimental design consisted of 3 [sound pressure level] x 3 [noise schedule] x 2 [noise type] factors. To investigate occupational skill performance, some specific test batteries were used: 1] steadiness test, 2] Minnesota manual dexterity test, 3] hand tool dexterity test, and 4] two-arm coordination test. Time duration of test completion was measured as speed response; to determine error response, the time taken during committing an error by participants while performing a task was measured. Speed response obtained from the 4 tests in combined conditions of noise schedule, harmonic index, and sound pressure level was highest for [intermittent, treble, 95 dB], [continuous, treble, 95 dB], [continuous, treble, 85 dB] and [intermittent, treble, 95 dB], respectively. Treble noise was found significant in reducing human performance; also, intermittent noise, especially at high pressure levels, was responsible for worsening environmental conditions during performing a task

Clinical features of cutaneous leishmaniasis and direct PCR-based identification of parasite species in a new focus in southeast of Iran

To clinically characterize the cutaneous leishmaniasis and identify the causative parasite species in Mirjaveh, an important geographical region across the border of Iran-Pakistan at Southeast of Iran. A number of 116 patients during a year since March 2005 to April 2006, subjected to the study. Clinical information collected and scrapings were taken from cutaneous lesions and used for microscopic examination, NNN cultivation and kinetoplast DNA-PCR amplification. The cases comprised of 48 males and 68 females, 84 [72.4%] Iranians and 32 [27.6%] non-Iranians. They aged between 2 months to 68 years with the most affection of children, 0-10 years [55.2%]. The patients presented a total of 248 active lesions with an average of 2.14. The ulcers distributed mostly on upper extremity [42.3%] then on face [32.7%], followed by lower extremity [20.6%] and other parts [4.4%]. The majority of ulcers stated to be developed rapidly, <1 month [40.3%] or 1-2 months [45.2%]. However, from 248 ulcers, only 19 [7.7%] found to be wet and the remaining were dry or moderately wet, 45 [18.1%] and 184 [74.2%], respectively. kDNA-PCR assay detected 51 out of 73 samples, all of which were identified as L. major, the causative agent of zoonotic cutaneous leishmaniasis. L. major is the species responsible for cutaneous leishmaniasis in Mirjaveh, however the pattern of clinical findings, does not completely resemble the ZCL characteristics. These indicate that the manifestation of the lesions may not necessarily correspond to the Leishmania species and may be unreliable to conclude the speciation of parasite without laboratory identification

Optimization of sample preparation for 1-hydroxypyrene as a major biomarker of exposure to PAHs prior to HPLC

Urinary 1-hydroxypuren [1-OHP] is commonly used as a major metabolite and biological indicator of the overall exposure to polycyclic aromatic hydrocarbons [PAHs]. For evaluation of human exposure to such compounds, biological monitoring is an essential process, in which, preparation of samples is one of the most time-consuming and error-prone aspects prior to chromatographic techniques. In this study, non classic form of liquid-liquid extraction [LLE] was optimized with regard to solvent type, solvent volume, extraction temperature, mixing type, and mixing duration. Through the extraction process, a mild temperature was used to keep the compound of interest as stable as possible. In this study, a high performance liquid chromatography, using reverse-phase column was used. The isocratic run was done at a constant flow rate of 0.8 ml/min, the mobile phase was methanol/water and a fluorescence detector was used, setting at 242 nm and 388 nm. At the developed conditions, the extraction recovery was exceeded 87.3%, achieving detection limit of 0.2 micro g/l. The factors were evaluated statically and the procedure was validated with three different pools of spiked urine samples and showed a good reproducibility over six consecutive days as well as experiments. It was concluded that, this optimized method could simplify sample preparation for trace residue analysis of PAHs metabolites