212 research outputs found

    Durations required to distinguish noise and tone: Effects of noise bandwidth and frequency.

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    Perceptual audio coders exploit the masking properties of the human auditory system to reduce the bit rate in audio recording and transmission systems; it is intended that the quantization noise is just masked by the audio signal. The effectiveness of the audio signal as a masker depends on whether it is tone-like or noise-like. The determination of this, both physically and perceptually, depends on the duration of the stimuli. To gather information that might improve the efficiency of perceptual coders, the duration required to distinguish between a narrowband noise and a tone was measured as a function of center frequency and noise bandwidth. In experiment 1, duration thresholds were measured for isolated noise and tone bursts. In experiment 2, duration thresholds were measured for tone and noise segments embedded within longer tone pulses. In both experiments, center frequencies were 345, 754, 1456, and 2658 Hz and bandwidths were 0.25, 0.5, and 1 times the equivalent rectangular bandwidth of the auditory filter at each center frequency. The duration thresholds decreased with increasing bandwidth and with increasing center frequency up to 1456 Hz. It is argued that the duration thresholds depended mainly on the detection of amplitude fluctuations in the noise bursts.MRC (G0701870

    Developing a Questionnaire for Iranian Women's Attitude on Medical Ethics in Vaginal Childbirth

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    Background: Vaginal delivery is one of the challenging issues in medical ethics. It is important to use an appropriate instrument to assess medical ethics attitudes in normal delivery, but the lack of tool for this purpose is clear. Objectives: The aim of this study was to develop and validate a questionnaire for the assessment of women’s attitude on medical ethics application in normal vaginal delivery. Patients and Methods: This methodological study was carried out in Iran in 2013 - 2014. Medical ethics attitude in vaginal delivery questionnaire (MEAVDQ) was developed using the findings of a qualitative data obtained from a grounded theory research conducted on 20 women who had vaginal childbirth, in the first phase. Then, the validation criteria of this tool were tested by content and face validity in the second phase. Exploratory factor analysis was used for construct validity and reliability was also tested by Cronbach’s alpha coefficient in the third phase of this study. SPSS version 13 was used in this study. The sample size for construct validity was 250 females who had normal vaginal childbirth. Results: In the first phase of this study (tool development), by the use of four obtained categories and nine subcategories from grounded theory and literature review, three parts (98-items) of this tool were obtained (A, B and J). Part A explained the first principle of medical ethics, part B pointed to the second and third principles of medical ethics, and part J explained the fourth principle of medical ethics. After evaluating and confirming its face and content validity, 75 items remained in the questionnaire. In construct validity, by the employment of exploratory factor analysis, in parts A, B and J, 3, 7 and 3 factors were formed, respectively; and 62.8%, 64% and 51% of the total variances were explained by the obtained factors in parts A, B and J, respectively. The names of these factors in the three parts were achieved by consideration of the loading factor and medical ethics principles. The subscales of MEAVDQ showed significant reliability. In parts A, B and J, Cronbach’s alpha coefficients were 0.76, 0.72 and 0.68, respectively and for the total questionnaire, it was 0.72. The results of the test–retest were satisfactory for all the items (ICC = 0.60 - 0.95). Conclusions: The present study showed that the 59-item MEAVDQ was a valid and reliable questionnaire for the assessment of women’s attitudes toward medical ethics application in vaginal childbirth. This tool might assist specialists in making a judgment and plan appropriate for women in vaginal delivery management

    The status of retinoblastoma gene expression in brain tumors

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    Objective: Malignant brain tumors, including Glioblastoma Multiforme (GBM), are among the deadliest brain tumors. Given the fact that the expression of the retinoblastoma (RB) gene in malignant tumors can change the tumor behavior, we seek to investigate the alterations of RB expression in brain tumors. Materials and Methods: The archives of the Pathology Department of Yazd Hospitals were examined, and all the brain tumors diagnosed between 2013 and 2017 were extracted. All paraffin embedded blocks underwent immunohistochemical staining for RB gene expression. Based on a pre-set checklist, demographics data, tumor type, location, and survival status were entered into and analyzed by SPSS version 25. p-value less than 0.05 was considered statistically significant. Results: Out of 90 blocks studied, 64.4% belonged to male patients and 35.5% to female patients. The frequencies of brain tumors subtypes were non-glioma (45.6%), low grade astrocytoma (14.4%), anaplastic astrocytoma (18.9%) and GBM (21.1%), respectively. The intensity of RB expression was significantly different between men and women (p-value=0.008), and in different subtypes of the tumors (p=0.04). Multivariate analysis revealed that GBM (HR: 9.933, 95% CI 1.888-52.254, p-value=0.007), age >50 (HR: 8.648, 95% CI 5.116-16.406, p-value= 0.0001), female sex (HR:2.139, 95% CI 1.212-3. 775, p-value= 0.09), RB negative tumors (HR:2.502, 95% CI 1.061-5.896, p-value= 0.036) significantly affect patient survival. Conclusions: There was a significant difference between men and women, and among different subtypes of the brain tumors in terms of RB gene expression. RB expression had a significant effect on patient survival independent from patient’s age, sex, and tumor subtypes

    Development of Sensitive Detection of Cryptosporidium and Giardia from Surface Water in Iran

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    Background: The protozoan parasites Cryptosporidium spp. and Giardia are known to occur widely in both raw and drinking waters. They are two of the causative agents of waterborne out-breaks of gastroenteritis throughout the world. In the present study, a PCR assay and FA were developed for detection of Cryptosporidium oocysts and Giardia cyst in environmental samples. Methods: We have detected Cryptosporidium spp. oocysts and Giardia cysts in seeded and un-seeded environmental water samples by PCR method. Water samples were spiked with oocysts (50, 100,300,500) and filtrated with a 1.2-µm pore size cellulose nitrate and follow by DNA extrac¬tion and purification by QIAamp DNA mini kit. Nested-PCR assay amplified an 850 bp fragment of 18s rRNA gene specific for Cryptosporidium and 435 bp fragment of glutamate dehydrogenase (GDH) target gene for Giardia. Also many river water from north of Iran, be checked by these methods. Results: Cryptosporidium and Giardia DNAs were detected in seeded water sample and Giardia was detected in all 5 water samples from river in north of Iran by nested- PCR and FA. Also in one river water sample, Cryptosporidium was detected.Conclusion: This protocol is effective for detection of these waterborne parasites in treated and untreated water samples. This study can also serve as a platform for further investigations and research water source in Iran

    Proportional lumbar spine inter-vertebral motion patterns: a comparison of patients with chronic, non-specific low back pain and healthy controls

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    Introduction: Identifying biomechanical subgroups in chronic, non-specific low back pain (CNSLBP) populations from inter-vertebral displacements has proven elusive. Quantitative fluoroscopy (QF) has excellent repeatability and provides continuous standardised inter-vertebral kinematic data from fluoroscopic sequences allowing assessment of mid-range motion. The aim of this study was to determine whether proportional continuous IV rotational patterns were different in patients and controls. A secondary aim was to update the repeatability of QF measurement of range of motion (RoM) for inter-vertebral (IV) rotation

    Performance, kinetic, and biodegradation pathway evaluation of anaerobic fixed film fixed bed reactor in removing phthalic acid esters from wastewater

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    Emerging and hazardous environmental pollutants like phthalic acid esters (PAEs) are one of the recent concerns worldwide. PAEs are considered to have diverse endocrine disrupting effects on human health. Industrial wastewater has been reported as an important environment with high concentrations of PAEs. In the present study, four short-chain PAEs including diallyl phthalate (DAP), diethyl phthalate (DEP), dimethyl phthalate (DMP), and phthalic acid (PA) were selected as a substrate for anaerobic fixed film fixed bed reactor (AnFFFBR). The process performances of AnFFFBR, and also its kinetic behavior, were evaluated to find the best eco-friendly phthalate from the biodegradability point of view. According to the results and kinetic coefficients, removing and mineralizing of DMP occurred at a higher rate than other phthalates. In optimum conditions 92.5, 84.41, and 80.39% of DMP, COD, and TOC were removed. DAP was found as the most bio-refractory phthalate. The second-order (Grau) model was selected as the best model for describing phthalates removal
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