• Title/Summary/Keyword: Selective Advantage

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Marker Genes for in Vitro Selection of Transgenic Plants

  • Brasileiro, Ana C.M.;Aragao, Francisco J.L.
    • Journal of Plant Biotechnology
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    • v.3 no.3
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    • pp.113-121
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    • 2001
  • The use of a marker gene in a transformation process aims to give a selective advantage to the transformed cells, allowing them to grow faster and better, and to kill the non-transformed cells. In general, the selective gene is introduced into plant genome along with the genes of interest. In some cases, the marker gene can be the gene of interest that will confer an agronomic characteristic, such as herbicide resistance. In this review we list and discuss the use of the most common selective marker genes on plant transformation and the effects of their respective selective agents. These genes could be divided in categories according their mode of action: genes that confer resistance to antibiotics and herbicides; and genes for positive selection. The contention of the marker gene flow through chloroplast transformation is further discussed. Moreover, strategies to recover marker-free transgenic plants, involving multi-auto-transformation (MAT), co-transformation, site specific recombination and intragenomic relocation of transgenes through transposable elements, are also reviewed.

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Prevalence of negative frequency-dependent selection, revealed by incomplete selective sweeps in African populations of Drosophila melanogaster

  • Kim, Yuseob
    • BMB Reports
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    • v.51 no.1
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    • pp.1-2
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    • 2018
  • Positive selection on a new beneficial mutation generates a characteristic pattern of DNA sequence polymorphism when it reaches an intermediate allele frequency. On genome sequences of African Drosophila melanogaster, we detected such signatures of selection at 37 candidate loci and identified "sweeping haplotypes (SHs)" that are increasing or have increased rapidly in frequency due to hitchhiking. Based on geographic distribution of SH frequencies, we could infer whether selective sweeps occurred starting from de novo beneficial mutants under simple constant selective pressure. Single SHs were identified at more than half of loci. However, at many other loci, we observed multiple independent SHs, implying soft selective sweeps due to a high beneficial mutation rate or parallel evolution across space. Interestingly, SH frequencies were intermediate across multiple populations at about a quarter of the loci despite relatively low migration rates inferred between African populations. This invokes a certain form of frequency-dependent selection such as heterozygote advantage. At one locus, we observed a complex pattern of multiple independent that was compatible with recurrent frequency-dependent positive selection on new variants. In conclusion, genomic patterns of positive selection are very diverse, with equal contributions of hard and soft sweeps and a surprisingly large proportion of frequency-dependent selection in D. melanogaster populations.

Novel Adaptive Distributed Compressed Sensing Algorithm for Estimating Channels in Doubly-Selective Fading OFDM Systems

  • Song, Yuming;He, Xueyun;Gui, Guan;Liang, Yan
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.5
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    • pp.2400-2413
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    • 2019
  • Doubly-selective (DS) fading channel is often occurred in many orthogonal frequency division multiplexing (OFDM) communication systems, such as high-speed rail communication systems and underwater acoustic (UWA) wireless networks. It is challenging to provide an accurate and fast estimation over the doubly-selective channel, due to the strong Doppler shift. This paper addresses the doubly selective channel estimation problem based on complex exponential basis expansion model (CE-BEM) in OFDM systems from the perspective of distributed compressive sensing (DCS). We propose a novel DCS-based improved sparsity adaptive matching pursuit (DCS-IMSAMP) algorithm. The advantage of the proposed algorithm is that it can exploit the joint channel sparsity information using dynamic threshold, variable step size and tailoring mechanism. Simulation results show that the proposed algorithm achieves 5dB performance gain with faster operation speed, in comparison with traditional DCS-based sparsity adaptive matching pursuit (DCS-SAMP) algorithm.

Area selective atomic layer deposition via surface reaction engineering: a review (표면 반응 제어를 통한 영역 선택적 원자층 증착법 연구 동향)

  • Ko, Eun-Chong;Ahn, Ji Sang;Han, Jeong Hwan
    • Journal of the Korean institute of surface engineering
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    • v.55 no.6
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    • pp.328-341
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    • 2022
  • Area selective atomic layer deposition (AS-ALD) is a bottom-up nanopattern fabrication method that can grow the ALD films only on the desired substrate areas without using photolithography and etching processes. Particularly, AS-ALD has attracted great attention in the semiconductor manufacturing process due to its advantage in reducing edge placement error by fabricating self-aligned patterns. In this paper, the basic principles and characteristics of AS-ALD are described. In addition, various approaches for achieving AS-ALD with excellent selectivity were comprehensively reviewed. Finally, the technology development to overcome the selectivity limit of AS-ALD was introduced along with future prospects.

Office-Based 585 nm Pulsed Dye Laser(PDL) Laryngeal Surgery (외래에서 시행되는 585 nm 펄스다이레이져 후두수술)

  • Kim, Hyung-Tae
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.20 no.1
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    • pp.25-30
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    • 2009
  • Introduction: 585 nm Pulsed dye laser (PDL) laryngeal surgery is based on the photodynamic characteristics of selective photothermolysis and photoangiolysis and recently considered to be the treatment for a variety of benign laryngeal disease. Objective: To review the indications and outcome of office-based 585nm PDL surgery and summarize new developments. Method: Retrospective study involving 402 patients was performed, The PDL surgery could be applied to various laryngeal diseases such as laryngeal papilloma, vocal fold dysplasia, laryngeal granuloma, vocal polyp, capillarectasia, scarred vocal fold and sulcus vocalis. Results : The physiologic properties of the vascular specificity of PDL provide many advantages and appear to be effective for laryngeal treatment. The PDL resulted in precise, selective coagulation of the microvasculature without damage to the surrounding tissue. Therefore PDL surgery is safe and effective for office-based treatment of benign laryngeal disease and for all patients regardless of their overall medical condition. Conclusion: PDL surgery provides potential benefits and advantage for treating common benign laryngeal disease.

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Localized Induction-Heating Method by the Use of Selective Mold Material (재료의 선택적 사용에 의한 금형의 국부적 유도가열기법)

  • Park, Keun;Do, Bum-Suk;Park, Jung-Min;Lee, Sang-Ik
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.05a
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    • pp.168-171
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    • 2009
  • High-frequency induction is an efficient way to heat mold surface by electromagnetic induction in a non-contact procedure. Though the induction heating has an advantage in terms of its rapid-heating capacity on the mold surface, it still has a restriction on mold temperature control due to geometric restriction of an induction coil according to the mold shape. It has been recently applied to the injection molding of thin-walled parts or micro/nano structures. For localized induction heating, an injection mold composed of ferromagnetic material and paramagnetic material is used. The electromagnetic induction concentrates on the ferromagnetic material, from which we can selectively heat for the local mold elements. The present study proposed a localized induction heating method by means of selective use of mold material. The feasibility of the proposed heating method is investigated through the comparison of experimental observations according to the mold material.

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Preparation and Characterization of Folic Acid Linked Poly(L-glutamate) Nanoparticles for Cancer Targeting

  • Lee Yong-Kyu
    • Macromolecular Research
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    • v.14 no.3
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    • pp.387-393
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    • 2006
  • Nanoparticles of Poly(L-glutamic acid) (PG) conjugated to the anticancer drug paclitaxel and targeted moiety folic acid (FA) were synthesized and characterized in vitro. The nanoparticles were designed to take advantage of FA targeting to folate receptor (FR) positive cancer cells. The chemical composition of the conjugate was characterized by $^1H-NMR$, FTIR and UV/vis spectroscopy. The selective cytotoxicity of the FA-PG-paclitaxel conjugates was evaluated in FR positive cancer cells. The interaction of the conjugate was visualized by fluorescence microscopy with results confirming the successful preparation of the conjugate and the production of nanoparticles of about 200-300 nm in diameter. The amount of paclitaxel conjugated to FA-PG was 25% by weight. Cellular uptake of the conjugate was FA dependent, and the conjugate uptake was mediated specifically by the folate receptor. These results demonstrate the improved selective toxicity and effective delivery of an anticancer drug into FR bearing cells in vitro.

On Calculating Eigenvalues In Large Power Systems Using Modified Arnoldi Method

  • Lee, Byong-Jun;Iba, Kenjl;Hirose, Michio
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.734-736
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    • 1996
  • This paper presents a method of calculating a selective number of eigenvalues in power systems, which are rightmost, or are largest modulus. The modified Arnoldi method in conjunction with implicit shift OR-algorithm is used to calculate the rightmost eigenvalues. Algorithm requires neither a prior knowledge of the specified shifts nor the calculation of inverse matrix. The key advantage of the algorithm is its ability to converge to the wanted eigenvalues at once. The method is compared with the modified Arnoldi method combined with S-matrix transformation, where the eigenvalues having the largest modulus are to be determined. The two methods are applied to the reduced Kansai system. Convergence characteristics and performances are compared. Results show that both methods are robust and has good convergence properties. However, the implicit shift OR method is seen to be faster than the S-matrix method under the same condition.

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Secondary structure of the Irf7 5'-UTR, analyzed using SHAPE (selective 2'-hydroxyl acylation analyzed by primer extension)

  • Kim, Yun-Mi;Choi, Won-Young;Oh, Chang-Mok;Han, Gyoon-Hee;Kim, Young-Joon
    • BMB Reports
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    • v.47 no.10
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    • pp.558-562
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    • 2014
  • OASL1 is a member of the 2'-5'-oligoadenylate synthetase (OAS) family and promotes viral clearance by activating RNase L. OASL1 interacts with the 5'-untranslated region (UTR) of interferon regulatory factor 7 (Irf7) and inhibits its translation. To identify the secondary structure required for OASL1 binding, we examined the 5'-UTR of the Irf7 transcript using "selective 2'-hydroxyl acylation analyzed by primer extension" (SHAPE). SHAPE takes advantage of the selective acylation of residues in single-stranded regions by 1-methyl-7-nitroisatoic anhydride (1M7). We found five major acylation sites located in, or next to, predicted single-stranded regions of the Irf7 5'-UTR. These results demonstrate the involvement of the stem structure of the Irf7 5'-UTR in the regulation of Irf7 translation, mediated by OASL1.

Is Pancapsular Release More Effective than Selective Capsular Release for the Treatment of Adhesive Capsulitis?

  • Moon, Nam Hoon;Lee, Seung-Jun;Shin, Won Chul;Lee, Sang Min;Suh, Kuen Tak
    • Clinics in Shoulder and Elbow
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    • v.18 no.1
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    • pp.28-35
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    • 2015
  • Background: We assessed the effectiveness of arthroscopic capsular release for the treatment of adhesive capsulitis. Further, we tried to ascertain the clinical benefits, if any, of pancapsular release over selective capsular release, where the two differ by performing or not performing a posterior capsular release, respectively. Methods: Thirty-five consecutive patients with either primary or secondary adhesive capsulitis who failed conservative treatment for more than 6 months were enrolled in the study. A total of 16 patients allocated in group 1 received a pancapsular release that comprises the release of the rotator interval, anteroinferior capsular, and the posterior capsular release, whereas 19 patients in group 2 received a selective capsular release that comprises only the release of the rotator interval release and anteroinferior capsular release. The clinical outcomes, visual analogue scale (VAS) score, Constant score, and range of motion, were assessed preoperative and postoperatively. Results: In both groups, the preoperative VAS score, Constant score, and ROM showed a significant improvement by the 6-month follow-up. We found that the immediate postoperative internal rotation was significantly higher in group 1 than group 2. Despite significant differences seen between the two groups at the initial postoperative period, there were no significant differences in Constant score, VAS score, and the ROM at all the subsequent follow-ups between the two groups. Conclusions: Arthroscopic capsular release for the treatment of adhesive capsulitis is very effective. However, pancapsular release did not show any advantage over selective capsular release in terms of overall clinical outcome.