Cost-Effective Design of Amplifiers for Hearing Aides Using Nullors for Response Matching

This chapter starts reviewing Fixator-Norator Pairs (FNP) as an effective tool used to design analog amplifiers for a prescribed bandwidth and frequency profile. Among number of cases and applications, designing for hearing aides are particularly important, where the hearing frequency profiles, known as audiograms, are changing from person to person, and also for a person by the age. The design is mainly focused on front-end or stand-alone amplifiers. In case of a front-end the response from the amplifier can be digitized, properly controlled and adjusted to fit the digital application. Here is how the design proceed. For a given audiogram, an Audiogram Generator Circuit (AGC) is initially constructed. This AGC, usually a complete passive circuit, produces a frequency response that closely matches with the audiogram, obtained from a hearing impaired patient. The AGC is then embedded in an amplifier circuit where a fixator is placed at its output port, “forcing” the amplifier to generate the desired output frequency response profile. A flat band frequency response, for example, compensates the hearing losses and provides a uniform hearing to the patient in the entire audio bandwidth. The amplifier can be further enhanced to perform other requirements, for example, to cancel undesirable noises in certain frequencies or to magnify the voice in critical frequencies for clarity. Another alternative design methodology is also introduced in this chapter, which uses the negative feedback technique

The Development of Conceptual Fluency and Metaphorical Competence in L2 Learners

Conceptual Fluency (CF) and Metaphorical Competence (MC) have piqued the interest of a number of L2 researchers. Leading the front are Danesi (1992; 1995; 2003) and Johnson and Rosano (1993) who contend that metaphorical language cannot afford to be ignored by L2 curricula anymore. Their push is to instill in L2 learners a more functional communicative competence over a traditional formal competence. This article reports on a study carried out to scrutinize the development of CF and MC in Persian students of English. First, a group of language students (95 freshmen, 92 sophomores, 139 juniors, and 90 seniors) were tested to see whether they were conceptually and metaphorically competent, and the results showed they were almost bereft of such a competence, and the analysis of their written discourse uncovered a very low level of metaphorical density. The findings were in line with what Danesi (1992) has averred: L2 learners do not necessarily develop CF and MC after several years of study. Then, the juniors partook in the study for a six-month period in which they were exposed to and taught about the metaphorical language of English. The posttest results were indicative that they had developed their CF and MC to a large extent and that their written discourse was almost as metaphorically dense as that of native speakers. That is, the findings revealed that it is possible to develop CF and MC in a classroom setting. Finally, the data indicated that there is a relationship between CF and MC

Post-cataract surgery endophthalmitis: Brief literature review

AbstractPurposeTo investigate recent evidence in prophylaxis and management of post-cataract surgery endophthalmitis.MethodsWe conducted a literature search using Pubmed database for post cataract surgery endophthalmitis, and relevant articles were selected from original English papers published since 2015.ResultsForty-nine articles were published regarding post-cataract surgery endophthalmitis from January 2015 to February 2016. A low incidence of post-cataract surgery endophthalmitis has been reported. A growing number of articles are focusing on preventing endophthalmitis using intracameral antibiotics.ConclusionBased on the current evidence, intracameral antibiotics seems to be effective in preventing endophthalmitis after cataract surgery

Corneal endothelial cell density and morphology in normal Iranian eyes

BACKGROUND: We describe corneal endothelial cell density and morphology in normal Iranian eyes and compare endothelial cell characteristics in the Iranian population with data available in the literature for American and Indian populations. METHODS: Specular microscopy was performed in 525 eyes of normal Iranian people aged 20 to 85 years old. The studied parameters including mean endothelial cell density (MCD), mean cell area (MCA) and coefficient of variation (CV) in cell area were analyzed in all of the 525 eyes. RESULTS: MCD was 1961 ± 457 cell/mm(2 )and MCA was 537.0 ± 137.4 μm(2). There was no statistically significant difference in MCD, MCA and CV between genders (Student t-test, P = 0.85, P = 0.97 and P = 0.15 respectively). There was a statistically significant decrease in MCD with age (P < 0.001, r = -0.64). The rate of cell loss was 0.6% per year. There was also a statistically significant increase in MCA (P < 0.001,r = 0.56) and CV (P < 0.001, r = 0.30) from 20 to 85 years of age. CONCLUSION: The first normative data for the endothelium of Iranian eyes seems to confirm that there are no differences in MCD, MCA and CV between genders. Nevertheless, the values obtained in Iranian eyes seem to be different to those reported by the literature in Indian and American populations

Effect of silicon on rice blast disease

Silicon is the second most plentiful element in soil and is beneficial for a large variety of plants. It is concentrated in plant tissues in quantities similar to that of macronutrients. Considerable damages to plants caused by abiotic stresses such as drought stress, salinity stress, heavy metal stress and nutrient imbalance, as well as biotic stresses like insect pests and pathogens and even herbivorous attacks, have been reported to be reduced significantly by silicon application. Among rice diseases, blast is recognized as the most devastating one. Silicon fertilization has been reported to be efficacious in controlling and mitigating rice blast severity. Two different hypotheses are proposed for the ability of silicon to lessen disease severity. The first hypothesis emphasizes on silicon function as a mechanical barrier against appressorial penetration, while the second hypothesis is based upon the belief that silicon has some physiological roles in disease resistance

Characterisation of Magnaporthe oryzae isolates from rice in peninsular Malaysia

The genus Pyricularia (anamorph)/Magnaporthe (teleomorph) includes important destructive pathogens causing blast disease on various species from the family Poaceae. Thirty-five Magnaporthe isolates were collected from diseased rice plants (variety MR219) in different rice-growing regions of Malaysia, including the five states of Selangor,Penang, Kedah, Kelantan, and Perak between 2010 and 2014. DNA sequence analyses of the internal transcribed spacer (ITS), actin, β-tubulin and calmodulin gene regions, random amplified polymorphic DNA (RAPD) and intersimple sequence repeat (ISSR) analyses were conducted to analyse 35 Magnaporthe isolates. Phylogenetic analysis of the combined dataset confirmed the identification of all isolates as M. oryzae with a high distance from other Magnaporthe (Pyricularia) species. RAPD and ISSR analyses indicated the existence of a relatively low similarity index value among M. oryzae isolates through identification of four main clades. The clustering of RAPD and ISSR analyses demonstrated that there was a correlation between the isolates and their geographical origins

Lentiviral Mediated Overexpression of NGF in Adipose-derived Stem Cells

Introduction: Human adipose-derived stem cells (ADSCs) are multipotent stem cells that can self-renew and differentiate into various types of cells such as adipocytes, osteocytes, and neural cells. These stem cells can be isolated by minimally invasive technique in large amounts. ADSCs are a useful resource for cell therapy and regenerative medicine. Nerve growth factor (NGF) is the first neurotrophin factor discovered and characterized for its anti-apoptotic role in neural development. NGF can promote neuronal survival and neurite outgrowth and it also promotes neuron differentiation and migration. Moreover, research showed that NGF could protect axons from inflammatory damage, improve cognitive function in damaged brain models, and function in the prevention and treatment of neurological diseases like Alzheimer’s disease. In this study we use Lentiviral vector-mediated gene transfer technique to deliver NGF gene to ADSCs and overexpress this factor in ADSCs. Method and Materials: ADSCs extracted from human adipose tissue after lipoaspiration by digestion method. ADSCs characterized with Flowcytometry and differentiation assay in adipogenic and osteogenic differential media. The NGF gene was cloned in pCDH-513B-1 (System Bioscience, Mountain View, CA, United States) under a cytomegalovirus (CMV) promoter. Recombinant lentiviruses were produced according to the Prof. Trono lab protocol with some modifications in HEK 293T cells. The spinfection method was used to transduce ADSCs. NGF expression was assayed using fluorescent microscope to trace green fluorescent protein (GFP) marker, RT-PCR and western blotting. Results: Extracted ADSCs had mesenchymal morphology and differentiated into adipocytes and osteocytes in differentiating media. HEK293T easily transfected with pCDH-513B-1 and over 99% of them expressed GFP so we gathered pseudoviruses from the supernatant. ADSCs transduced with these pseudoviruses transferred NGF and after transduction expressed GFP, as seen under fluorescent microscope. RT-PCR and western blotting verified NGF overexpression in them