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Flexural fatigue modeling of short fibers/epoxy composites

  • Shokrieh, M.M.;Haghighatkhah, A.R.;Esmkhani, M.
    • Structural Engineering and Mechanics
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    • v.64 no.3
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    • pp.287-292
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    • 2017
  • In the present research, an available flexural stiffness degradation model was modified and a new comprehensive model called "X-NFSD" was developed. The X-NFSD model is capable of predicting the flexural stiffness degradation of composite specimen at different states of stresses and at room temperature. The model was verified by means of different experimental data for chopped strand mat/epoxy composites under displacement controlled bending loading condition at different displacements and states of stresses. The obtained results provided by the present model are impressively in very good agreement with the experimental data and the mean value of error of 5.4% was achieved.

Fatigue modeling of chopped strand mat/epoxy composites

  • Shokrieh, M.M.;Esmkhania, M.;Taheri-Behrooz, F.
    • Structural Engineering and Mechanics
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    • v.50 no.2
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    • pp.231-240
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    • 2014
  • In the present research, fatigue behavior of chopped strand mat/epoxy composites has been studied with two different techniques. First, the normalized stiffness degradation approach as a well-known model for unidirectional and laminated composites was utilized to predict the fatigue behavior of chopped strand mat/epoxy composites. Then, the capability of the fatigue damage accumulation model for chopped strand mat/epoxy composites was investigated. A series of tests has been performed at different stress levels to evaluate both models with the obtained results. The results of evaluation indicate a better correlation of the normalized stiffness degradation technique with experimental results in comparison with the fatigue damage accumulation model.

Damage detection in plates based on pattern search and Genetic algorithms

  • Ghodrati Amiri, G.;Seyed Razzaghi, S.A.;Bagheri, A.
    • Smart Structures and Systems
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    • v.7 no.2
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    • pp.117-132
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    • 2011
  • This paper is aimed at presenting two methods on the basis of pattern search and genetic algorithms to detect and estimate damage in plates using the modal data of a damaged plate. The proposed methods determine the damages of plate structures using optimization of an objective function by pattern search and genetic algorithms. These methods have been applied to two numerical examples, namely four-fixed supported and cantilever plates with and without noise in the modal data and containing one or several damages. The obtained results clearly reveal that the proposed methods can be viewed as a powerful and reliable method for structural damage detection in plates using the modal data.

Flutter behavior of graded graphene platelet reinforced cylindrical shells with porosities under supersonic airflow

  • Mohammad Mashhour;Mohammad Reza Barati;Hossein Shahverdi
    • Steel and Composite Structures
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    • v.46 no.5
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    • pp.611-619
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    • 2023
  • In the present work, the flutter characteristics of porous nanocomposite cylindrical shells, reinforced with graphene platelets (GPLs) in supersonic airflow, have been investigated. Different distributions for GPLs and porosities have been considered which are named uniform and non-uniform distributions thorough the shell's thickness. The effective material properties have been determined via Halpin-Tsai micromechanical model. The cylindrical shell formulation considering supersonic airflow has been developed in the context of first-order shell and first-order piston theories. The governing equations have been solved using Galerkin's method to find the frequency-pressure plots. It will be seen that the flutter points of the shell are dependent on the both amount and distribution of porosities and GPLs and also shell geometrical parameters.

Community Management System to Support Seamless Collaboration of Services (지속적인 협업 서비스를 지원하는 커뮤니티 관리 시스템)

  • Kim, Hyeon-Sook;Choi, Dong-Soon;Cho, Wee-Duck
    • 한국HCI학회:학술대회논문집
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    • 2006.02a
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    • pp.287-292
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    • 2006
  • 본 논문은 환경의 변화에 적응하여 지속적으로 서비스들의 협업을 지원하기 위한 통합 시스템으로 커뮤니티 관리 시스템을 제안한다. 이를 위해 커뮤니티라는 메타포를 사용하여 추상화된 레벨로 협업 모델을 정의하고 이를 런타임에 해석하여 물리적 환경의 실질적인 서비스들간의 실행 모델로 전환한다. 본 논문에서 제안한 시스템은 서비스들의 협업과 사용자의 인터랙션을 관리하는 커뮤니티 매니저(CM)와 서비스들의 협업모델을 실행 환경으로 매핑시키는 커뮤니티 프레임워크(CF) 그리고 CM 과 CF 에게 통합된 컨텍스트를 제공해 주는 시츄에이션 매니저(SM)로 구성되어 있다. 이 시스템에서 추상화된 협업 모델은 런타임에 물리적 공간으로 매핑되므로, 동적으로 실행 환경과 사용자의 특성을 인식하고 그에 맞는 협업 목표와 협업 대상을 변경시켜 실행 환경에 맞게 재구성 되는 것이 가능하다. 따라서 제안된 시스템을 통해 특정 환경에 고유하게 구축되던 시스템의 개발 비용에 대한 부담을 절감시키는 효과를 가져올 것으로 기대된다.

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Chronic progressive external ophthalmoplegia in a Saudi patient with a mutation in the POLG gene successfully managed with bilateral frontalis sling

  • Algahtani, Hussein;Shirah, Bader;Alsaggaf, Khalid;Al-Qahtani, Mohammad H.;Abdulkareem, Angham Abdulrahman;Naseer, Muhammad Imran;Abuzinadah, Ahmad R.
    • Journal of Genetic Medicine
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    • v.18 no.2
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    • pp.121-126
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    • 2021
  • Chronic progressive external ophthalmoplegia (CPEO) is a complex slowly progressive mitochondrial disorder characterized by extraocular muscle weakness with or without multisystem involvement. The mainstay of therapy in a patient with CPEO is supportive. However, in moderate cases, surgery might be indicated including surgeries for ptosis and strabismus. In this article, we report a Saudi patient with CPEO due to compound heterozygous variants in the DNA polymerase gamma (POLG) gene c.2246T>C p.(Phe749Ser) and c.1735C>T p.(Arg579Trp), which are classified as pathogenic. Proper diagnosis with genetic testing confirmation is important to guide the management and counsel the patient about the prognosis and the management options. The patient was successfully managed with bilateral frontalis sling and illustrates the importance of surgical intervention to improve vision and cosmetic appearance in patients with CPEO. We emphasize the importance of multidisciplinary care in the management of cases of mitochondriopathy, especially CPEO.

Expressed Sequence Tag Analysis for Identification and Characterization of Sex-Related Genes in the Giant Tiger Shrimp Penaeus monodon

  • Preechaphol, Rachanimuk;Leelatanawit, Rungnapa;Sittikankeaw, Kanchana;Klinbunga, Sirawut;Khamnamtong, Bavornlak;Puanglarp, Narongsak;Menasveta, Piamsak
    • BMB Reports
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    • v.40 no.4
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    • pp.501-510
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    • 2007
  • Sex-related genes expressed in vitellogenic ovaries of the giant tiger shrimp, Penaeus monodon, were identified by an EST approach. A total of 1051 clones were unidirectionally sequenced from the 5 terminus. Nucleotide sequences of 743 EST (70.7%) significantly matched known genes previously deposited in the GenBank (E-value <$10^{-4}$) whereas 308 ESTs (29.3%) were regarded as newly unidentified transcripts (E-value >$10^{-4}$). A total of 559 transcripts (87 contigs and 472 singletons) were obtained. Thrombospondin (TSP) and peritrophin (79 and 87 clones accounting for 7.5 and 8.3% of clones sequenced, respectively) predominated among characterized transcripts. everal full length transcripts (e.g. cyclophilin, profillin and thioredoxin peroxidase) were also isolated. A gene homologue encoding chromobox protein (PMCBX, ORF of 567 nucleotides encoding a protein of 188 amino acids) which is recognized as a new member of the HP1 family was identified. Expression patterns of 14 of 25 sex-related gene homologues in ovaries and testes of P. monodon broodstock were examined by RT-PCR. Female sterile and ovarian lipoprotein receptor homologues were only expressed in ovaries whereas the remaining transcripts except disulfide isomerase related P5 precursor and adenine nucleotide translocator 2 were higher expressed in ovaries than testes of P. monodon broodstock. A homologue of ubiquitin specific proteinase 9, X chromosome (Usp9X) revealed a preferential expression level in ovaries than testes of broodstock-sized P. monodon (N = 13 and 11, P<0.05) but was only expressed in ovaries of 4-month-old shrimp (N = 5 for each sex).

Comparison of Detection Sensitivity for Human Papillomavirus between Self-collected Vaginal Swabs and Physician-collected Cervical Swabs by Electrochemical DNA Chip

  • Nilyanimit, Pornjarim;Wanlapakorn, Nasamon;Niruthisard, Somchai;Takahashi, Masayoshi;Vongpunsawad, Sompong;Poovorawan, Yong
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.24
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    • pp.10809-10812
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    • 2015
  • Background: Human papillomavirus (HPV) DNA testing is an effective method to screen for precancerous changes in the cervix. Samples from self-collection rather than Pap smear can potentially be used to test for HPV as they are more acceptable and preferred for use in certain settings. The objective of this study was to compare HPV DNA testing from self-collected vaginal swabs and physician-collected cervical swabs. Materials and Methods: A total of 101 self-collected vaginal and physician-collected cervical swabs of known cytology from Thai women were tested by electrochemical DNA chip assay. The specimens were divided into 4 groups: 29 with normal cytology, 14 with atypical squamous cells of undetermined significance (ASCUS), 48 with low-grade squamous intraepithelial lesion (LSIL), and 10 with high-grade squamous intraepithelial lesion (HSIL). Results: Positive detection rates of HPV from self-collected swabs were similar to those from physician-collected swabs. Among specimens with abnormal cytology, HPV was found in 50% of self-collected swabs and 47.2% of physician-collected swabs. In specimens with normal cytology, 17.2% of self-collected swabs and 24.1% of physician-collected swabs were positive for HPV. Concordance was relatively high between results from self-collected and physician-collected samples. The most common HPV genotype detected was HPV 51. Conclusions: HPV DNA testing using self-collected swabs is a feasible alternative to encourage and increase screening for cervical cancer in a population who might otherwise avoid this important preventive examination due to embarrassment, discomfort, and anxiety.

Identification of Sex-specific Expression Markers in the Giant Tiger Shrimp (Penaeus monodon)

  • Khamnamtong, Bavornlak;Thumrungtanakit, Supaporn;Klinbunga, Sirawut;Aoki, Takashi;Hirono, Ikuo;Menasveta, Piamsak
    • BMB Reports
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    • v.39 no.1
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    • pp.37-45
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    • 2006
  • Bulked segregant analysis (BSA) and AFLP were used for isolation of genomic sex determination markers in Penaeus monodon. A total of 256 primer combinations were tested against 6-10 bulked genomic DNA of P. monodon. Five and one candidate female- and male-specific AFLP fragments were identified. Female-specific fragments were cloned and further characterized. SCAR markers derived from FE10M9520, FE10M10725.1, FE10M10725.2 and FE14M16340 provided the positive amplification product in both male and female P. monodon. Further analysis of these markers using SSCP and genome walk analysis indicated that they were not sex-linked. In addition, sex-specific (or differential) expression markers in ovaries and testes of P. monodon were analyzed by RAP-PCR (150 primer combinations). Twenty-one and fourteen RAP-PCR fragments specifically/differentially expressed in ovaries and testes of P. monodon were successfully cloned and sequenced. Expression patterns of 25 transcripts were tested against the first stranded cDNA of ovaries and testes of 3-month-old and broodstock-sized P. monodon (N = 5 and N = 7 - 10 for females and N = 4 and N = 5 - 7 for males, respectively). Five (FI-4, FI-44, FIII-4, FIII-39 and FIII-58) and two (M457-A01 and MII-51) derived RAP-PCR markers revealed female- and male-specific expression patterns in P. monodon. Surprisingly, MII-5 originally found in testes showed a higher expression level in ovaries than did testes of juvenile shrimps but a temporal female-specific pattern in P. monodon adults.