1,116 research outputs found
Introduction of a novel 18S rDNA gene arrangement along with distinct ITS region in the saline water microalga Dunaliella
Comparison of 18S rDNA gene sequences is a very promising method for identification and classification of living organisms. Molecular identification and discrimination of different Dunaliella species were carried out based on the size of 18S rDNA gene and, number and position of introns in the gene. Three types of 18S rDNA structure have already been reported: the gene with a size of ~1770 bp lacking any intron, with a size of ~2170 bp consisting one intron near 5' terminus, and with a size of ~2570 bp harbouring two introns near 5' and 3' termini. Hereby, we report a new 18S rDNA gene arrangement in terms of intron localization and nucleotide sequence in a Dunaliella isolated from Iranian salt lakes (ABRIINW-M1/2). PCR amplification with genus-specific primers resulted in production of a ~2170 bp DNA band, which is similar to that of D. salina 18S rDNA gene containing only one intron near 5' terminus. Whilst, sequence composition of the gene revealed the lack of any intron near 5' terminus in our isolate. Furthermore, another alteration was observed due to the presence of a 440 bp DNA fragment near 3' terminus. Accordingly, 18S rDNA gene of the isolate is clearly different from those of D. salina and any other Dunaliella species reported so far. Moreover, analysis of ITS region sequence showed the diversity of this region compared to the previously reported species. 18S rDNA and ITS sequences of our isolate were submitted with accesion numbers of EU678868 and EU927373 in NCBI database, respectively. The optimum growth rate of this isolate occured at the salinity level of 1 M NaCl. The maximum carotenoid content under stress condition of intense light (400 μmol photon m-2 s-1), high salinity (4 M NaCl) and deficiency of nitrate and phosphate nutritions reached to 240 ng/cell after 15 days
Face recognition using curvelet transform
This paper presents a new method for the problem of human face recognition from still images. This is based on a multiresolution analysis tool called Digital Curvelet Transform. Curvelet transform has better directional and edge representation abilities than wavelets. Due to these attractive attributes of curvelets, we introduce this idea for feature extraction by applying the curvelet transform of face images twice. The curvelet coefficients create a representative feature set for classification. These coefficients set are then used to train gradient descent backpropagation neural network (NN). A comparative study with wavelet-based, curvelet-based, and traditional Principal Component Analysis (PCA) techniques is also presented. High accuracy rate of 97 achieved by the proposed method for two well-known databases indicates the potential of this curvelet based curvelet feature extraction method
A Comparative Study on the Optimal Modeling of Laminated Glass
This study addresses the challenging task of modeling laminated glass responses to extreme loading scenarios for the design and analysis of protective structures. The primary objective is to seek an optimal modeling approach that balances accuracy and computational efficiency. To achieve this, the failure modeling of laminated glass layups comprising thin and thick panels with three and eleven layers is investigated under blast loading conditions. Various simulation techniques are employed, including the finite element method (FEM) with element erosion/deletion, smoothed particle hydrodynamics (SPH), and a hybrid approach involving the conversion of elements into particles. The feasibility and limitations of each technique are examined, considering both accuracy and computational cost. Experimental results from arena and shock tube testing scenarios assess the deployed modeling techniques and the presented comparisons. Emphasis is placed on mesh sensitivity and the significance of adaptive meshing in capturing fracture patterns. The present paper suggests that utilizing hybrid techniques results in optimal modeling outcomes. Furthermore, the stability of the modeling results under diverse blast conditions is confirmed. This article contributes to the field by offering insights into modeling laminated glass responses to extreme loading, emphasizing the use of hybrid techniques to strike a balance between accuracy and computational efficiency. This research enhances the understanding of protective structure design and analysis, highlighting the critical importance of computational methods in this context. Doi: 10.28991/CEJ-2023-09-11-018 Full Text: PD
Vulnerability Reduction of Technology-Based Business research in the Last four Decades: A Bibliometric Analysis
Natural and man-made disasters have increased the attention of practitioners and researchers to vulnerability. Identifying business vulnerability is one of the basic elements of strategic analysis and public policy. The purpose of this paper is to explore evolutionary pathways to reduce the vulnerability of technology-based businesses. The intellectual structure of this subject was examined using both bibliometric co-occurrence and co-citation analyses. We focused on 629 articles published between 1981 and 2021. This article identifies four specific areas. Business performance, small business vulnerability, sources of sustainability in business, and adaptation policy assessment. A novel framework was developed based on the most prominent papers identified in co-citation, and the highly cited papers. The proposed model includes drivers, vulnerability appearance, and vulnerability reduction. This study examines the basis of research concepts, themes, and communities in reducing the vulnerability of technology-based businesses. This article identifies business vulnerability as one of the relevant areas to disaster economics and sustainability studies
Population‐specific modelling of between/within‐subject flow variability in the carotid arteries of the elderly
Computational fluid dynamics models are increasingly proposed for assisting the diagnosis and management of vascular diseases. Ideally, patient‐specific flow measurements are used to impose flow boundary conditions. When patient‐specific flow measurements are unavailable, mean values of flow measurements across small cohorts are used as normative values. In reality, both the between‐subjects and within‐subject flow variabilities are large. Consequently, neither one‐shot flow measurements nor mean values across a cohort are truly indicative of the flow regime in a given person. We develop models for both the between‐subjects and within‐subject variability of internal carotid flow. A log‐linear mixed effects model is combined with a Gaussian process to model the between‐subjects flow variability, while a lumped parameter model of cerebral autoregulation is used to model the within‐subject flow variability in response to heart rate and blood pressure changes. The model parameters are identified from carotid ultrasound measurements in a cohort of 103 elderly volunteers. We use the models to study intracranial aneurysm flow in 54 subjects under rest and exercise and conclude that OSI, a common wall shear‐stress derived quantity in vascular CFD studies, may be too sensitive to flow fluctuations to be a reliable biomarker
Treatment of Steroid and Cyclosporine-Resistant Idiopathic Nephrotic Syndrome in Children
Steroid-resistant nephrotic syndrome (SRNS) in children carries a significant risk of progression to end-stage renal failure (ESRF). We report a two-step protocol adapted in children with SRNS. Thirty-seven SRNS were treated with cyclosporine A (CyA) in association with prednisolone (alternate day) for 6 months (first-step treatment). Twelve patients (32.4%) went into complete remission, and 2 (5.4%) got partial remission.
The other 23 cases who were steroid and CyA resistant entered a second-step treatment with withdrawing steroids, with CyA (5 mg/kg/day) in association with mycophenolate mofetil (MMF) 30 mg/kg/day for 6 months. Complete remission was observed in 11 cases (47.82%) and partial remission in 2 cases (8.7%).
After two steps of treatment, 27/37 children went into total remission. In steroid and CyA-resistant INS, the association of MMF with CyA was able to induce remission in about half cases without relevant side effects
Comparison of long-pulsed alexandrite laser and topical tretinoin-ammonium lactate in axillary acanthosis nigricans: A case series of patients in a before-after trial
Background: Acanthosis nigricans (AN) is a brown to black, velvety hyperpigmentation of the skin that usually involves cutaneous folds. Treatment of AN is important regarding cosmetic reasons and various therapeutic modalities have been used for these purposes. The goal of this study was to compare the effectiveness of long-pulsed alexandrite laser and topical tretinoin-ammonium lactate for treatment of axillary-AN. Methods: Fifteen patients with bilateral axillary-AN were studied in Razi Hospital, Tehran, Iran. Diagnosis was confirmed by two independent dermatologists. Each side skin lesion was randomly allocated to either topical mixed cream of tretinoin 0.05- ammonium lactate 12 or long-pulsed alexandrite laser. Duration of treatment was 14 weeks. At endpoint, the mean percent reduction from baseline in pigmentation area was compared between the two groups. Results: The study population consisted of 15 patients three males and 12, females. The mean age of patients was 28.5±4.9 years. The mean percent reduction was 18.3±10.6, in tretinoin/ammonium lactate group and 25.7±11.8 in laser group (P=0.004). Conclusion: These findings indicate that the application of alexandrite laser is a relative effective method for treatment of axillary-AN. However, this issue requires further studies with prolonged follow-up period
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