Journal articles: 'Iris scanning'

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OTA, H. "Proposal of a Transformation Method for Iris Codes in Iris Scanning Verification." IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E88-A, no. 1 (January 1, 2005): 287–95. http://dx.doi.org/10.1093/ietfec/e88-a.1.287.

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M.Sarhan, Ahmad. "A WPD Scanning Technique for Iris Recognition." International Journal of Computer Applications 85, no. 14 (January 16, 2014): 6–12. http://dx.doi.org/10.5120/14907-3446.

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Castanera, Fernando, Graciana Fuentes-Páez, Pau Ten, Beatriz Pinalla, and Osvaldo Guevara. "Scanning electron microscopy of explanted cosmetic iris implants." Clinical & Experimental Ophthalmology 38, no. 6 (April 29, 2010): 648–51. http://dx.doi.org/10.1111/j.1442-9071.2010.02315.x.

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Na, Li, Danu Widatama, Tony Mulia, and Benyamin Kusumoputro. "Circular Construction of Iris Feature Vectors for Human Iris Recognition Systems." Applied Mechanics and Materials 330 (June 2013): 991–95. http://dx.doi.org/10.4028/www.scientific.net/amm.330.991.

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In this paper, the authors propose a new method to construct feature vectors of human iris based on circular technique. Since an iris has a circular shape, the circular construction of the iris feature vector is expected to have higher ability to capture iris characteristics. Different from the conventional method which constructs iris feature vectors through left to right scanning process, the circular technique scans the pixel-intensity value of iris circularly. As the result, the length of the constructed feature vectors is dependent on the length of iris radius. In the experiments, various recognition methods of feature vectors were compared. The iris recognition results show that the proposed system with Statistical Euclidean Distance method gives the highest recognition accuracy with 84.5%.

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Fryczkowski, Andrzej W., Barton L. Hodes, and Jonathan Walker. "Diabetic choroidal and iris vasculature scanning electron microscopy findings." International Ophthalmology 13, no. 4 (July 1989): 269–79. http://dx.doi.org/10.1007/bf02280087.

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Zola Matuvanga, Trésor, Ginger Johnson, Ynke Larivière, Emmanuel Esanga Longomo, Junior Matangila, Vivi Maketa, Bruno Lapika, et al. "Use of Iris Scanning for Biometric Recognition of Healthy Adults Participating in an Ebola Vaccine Trial in the Democratic Republic of the Congo: Mixed Methods Study." Journal of Medical Internet Research 23, no. 8 (August 9, 2021): e28573. http://dx.doi.org/10.2196/28573.

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Background A partnership between the University of Antwerp and the University of Kinshasa implemented the EBOVAC3 clinical trial with an Ebola vaccine regimen administered to health care provider participants in Tshuapa Province, Democratic Republic of the Congo. This randomized controlled trial was part of an Ebola outbreak preparedness initiative financed through Innovative Medicines Initiative-European Union. The EBOVAC3 clinical trial used iris scan technology to identify all health care provider participants enrolled in the vaccine trial, to ensure that the right participant received the right vaccine at the right visit. Objective We aimed to assess the acceptability, accuracy, and feasibility of iris scan technology as an identification method within a population of health care provider participants in a vaccine trial in a remote setting. Methods We used a mixed methods study. The acceptability was assessed prior to the trial through 12 focus group discussions (FGDs) and was assessed at enrollment. Feasibility and accuracy research was conducted using a longitudinal trial study design, where iris scanning was compared with the unique study ID card to identify health care provider participants at enrollment and at their follow-up visits. Results During the FGDs, health care provider participants were mainly concerned about the iris scan technology causing physical problems to their eyes or exposing them to spiritual problems through sorcery. However, 99% (85/86; 95% CI 97.1-100.0) of health care provider participants in the FGDs agreed to be identified by the iris scan. Also, at enrollment, 99.0% (692/699; 95% CI 98.2-99.7) of health care provider participants accepted to be identified by iris scan. Iris scan technology correctly identified 93.1% (636/683; 95% CI 91.2-95.0) of the participants returning for scheduled follow-up visits. The iris scanning operation lasted 2 minutes or less for 96.0% (656/683; 95% CI 94.6-97.5), and 1 attempt was enough to identify the majority of study participants (475/683, 69.5%; 95% CI 66.1-73.0). Conclusions Iris scans are highly acceptable as an identification tool in a clinical trial for health care provider participants in a remote setting. Its operationalization during the trial demonstrated a high level of accuracy that can reliably identify individuals. Iris scanning is found to be feasible in clinical trials but requires a trained operator to reduce the duration and the number of attempts to identify a participant. Trial Registration ClinicalTrials.gov NCT04186000; https://clinicaltrials.gov/ct2/show/NCT04186000

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Lee, ReA, and Jongjun Kim. "A Study on the Three-dimensional Expression of Fashionable Textiles based on Analyses of 3D Scanning and Textile Properties -Focus on the Work of Iris van Herpen-." Fashion business 20, no. 2 (May 30, 2016): 124–33. http://dx.doi.org/10.12940/jfb.2016.20.2.124.

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Anderson, Michael G., Tamás Haraszti, Greg E. Petersen, Sue Wirick, Chris Jacobsen, Simon W. M. John, and Michael Grunze. "Scanning transmission X-ray microscopic analysis of purified melanosomes of the mouse iris." Micron 37, no. 8 (December 2006): 689–98. http://dx.doi.org/10.1016/j.micron.2006.03.008.

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Midha, Neha, Kirsten Hoskens, and Kaweh Mansouri. "Pattern Scanning Laser (PASCAL) for Peripheral Iridoplasty in Eyes With Plateau Iris Syndrome." Journal of Glaucoma 27, no. 7 (July 2018): e124-e127. http://dx.doi.org/10.1097/ijg.0000000000000982.

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Aravindhan, Baheerathan, Kalam Sabrina, Grote Helen, Mcnamara Cillian, Rane Neil, and Nicholas Richard. "WED 170 The utility of brain FDG-PET in a patient with natalizumab associated PML-IRIS." Journal of Neurology, Neurosurgery & Psychiatry 89, no. 10 (September 13, 2018): A21.3—A21. http://dx.doi.org/10.1136/jnnp-2018-abn.77.

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Natalizumab, a highly effective disease modifying drug used in relapsing remitting multiple sclerosis (RRMS), is associated with progressive multifocal leukoencephalopathy (PML), a fatal intracerebral demyelinating disease caused by the JC virus that can be worsened with concurrent use of steorids. Stopping natalizumab in the context of PML can cause immune reconstitution inflammatory syndrome (IRIS) that can be treated with steroids. IRIS can be indistinguishable from PML on MRI - thus causing a clinical conundrum.We describe a woman with RRMS on Natalizumab who developed dysarthria and right-sided hemiparesis. MRI demonstrated non-enhancing peridentate white matter signal abnormality in the right middle cerebellar peduncle (RMCP). Cerebrospinal fluid JC virus DNA was >1 million copies/ml. PML was diagnosed and Natalizumab withdrawn. Four weeks later she developed bulbar weakness and left-sided hemiparesis despite falling JC virus DNA. Repeat MRI demonstrated new extensive pontine changes consistent with PML-IRIS.FDG-PET imaging confirmed focal areas of hypometabolism at the original site of PML and multiple areas of hypermetabolism in the left pons and middle cerebellar peduncle, suggestive of IRIS. Her clinical deterioration was attributed to IRIS and Prednisolone was commenced.In this case FDG-PET scanning helped distinguish between PML and IRIS, guiding patient management.

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Chan, Anthony, Nagina Parmar, Anusha Jega, Christopher Yip, Forough Farrokhyar, and Mark J. Walton. "Quantitiative Analysis of Roughness of Catheters by Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM)." Blood 106, no. 11 (November 16, 2005): 3218. http://dx.doi.org/10.1182/blood.v106.11.3218.3218.

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Abstract Thrombosis is a major complication of central venous access devices, and incidence depends on material, diameter, tip position, and tip surface. Catheters are usually cut to the appropriate length for accurate positioning. However, cutting is not recommended as rough surfaces can serve as a nidus for thrombi. This study was done to assess the roughness of the catheter tips as provided by various manufacturers, versus the roughness once cut and handled. Four types of catheters (Groschong, Hickman, Port-a-Cath, and Per Q Cath) were cut by scissors, iris scissors, or scalpel, and handled with debakey forceps, a needle driver, and adsons with or without teeth, to determine the damage created on the catheter. The manufactured tip was compared as a control. Scanning electron microscopy (SEM) was used to do imaging for all samples and roughness and section analysis was quantified using atomic force microscopy (AFM) for the cutting methods. SEM showed that scalpel-cut and manufactured ends appeared smoother relative to those cut with scissors or iris scissors (Fig 1). This complemented the roughness and section analysis by AFM (Fig 2). Catheters handled by debakey equipment and adsons with teeth showed the most roughness, visible as deep holes or a grainy surface when observed by high magnification SEM. Decreasing smoothness of catheters is in the following order: uncut surface, followed by surfaces cut by scalpel, scissors or iris scissors. Handling should be minimized and use of adsons with teeth, needle drivers and debakey forceps avoided, which can leave permanent damage. The least damage appeared to be adsons without teeth. Thus, the cutting of catheters is not recommended since rough surfaces can serve as a thrombotic nidus. Figure Figure

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Yuan, Chengqing, Zhongxiao Peng, and Xinping Yan. "Surface Characterization Using Wavelet Theory and Confocal Laser Scanning Microscopy." Journal of Tribology 127, no. 2 (April 1, 2005): 394–404. http://dx.doi.org/10.1115/1.1866161.

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Surface characterization, particularly roughness analysis, is very important for a wide range of applications including wear assessment. This paper proposes a set of methods and techniques to acquire appropriate images using confocal laser scanning microscopy, to separate roughness, waviness, and form using wavelet theory, and to characterize surface roughness for engineering surfaces and surfaces of small particles. Two application examples on engineering surfaces and wear particles have been presented in the paper to demonstrate that the method developed in this study can be used to measure surface roughness reliably and precisely. A guide on how to determine the iris size, step size, and objective lens has been scientifically provided according to theoretical analysis and experimental results.

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Kobayashi, Yui, Shunsuke Nakakura, Etsuko Terao, Yuki Fujio, Kanae Matsuya, Hitoshi Tabuchi, Yasuhiro Takahashi, and Yoshiaki Kiuchi. "Iris Morphological Features in Patients with 360° Angle-Closure Neovascular Glaucoma: An Anterior Segment Optical Coherence Tomography Study." Case Reports in Ophthalmology 9, no. 3 (October 25, 2018): 449–56. http://dx.doi.org/10.1159/000493418.

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Purpose: To investigate iris morphological features in 360° angle-closure neovascular glaucoma (NVG) by swept-source anterior segment optical coherence tomography (ASOCT). Patients and Methods: In this retrospective, clinic-based, comparative study, 14 patients with 360° angle-closure NVG and 14 healthy age-matched control subjects were enrolled. All patients enrolled had no prior glaucoma surgery but underwent cataract surgery with intraocular lens implantation. Horizontal scanning images of swept-source ASOCT were analyzed using software calipers in temporal and nasal angle areas. The iris thickness at 1 and 2 mm from the pupil edge, iris length, trabecular meshwork length, peripheral anterior synechia (PAS) length, PAS height ratio (PAS length/trabecular meshwork length), and pupil diameter were measured. Results: Between the groups, there were no statistically significant differences in iris length, trabecular meshwork length, and pupil diameter (p > 0.05). However, the iris thickness was significantly reduced in the NVG group compared with the control group in the temporal and nasal areas (0.306 vs. 0.563 mm/0.326 vs. 0.645 mm at 1 mm, 0.278 vs. 0.523 mm/0.282 vs. 0.546 mm at 2 mm, respectively) (mean, all p < 0.001). In the NVG group, PAS height ratios were 1.55 ± 0.45 (mean ± standard deviation) (range, 0.58–2.30) and 1.55 ± 0.78 (range, 0.68–3.68) at the temporal and nasal angles, respectively. Conclusions: In patients with 360° angle-closure NVG, the iris thickness decreased to about 50% of that in healthy subjects, and the PAS length exceeded the trabecular meshwork length by about 1.5 times.

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Burstein, Neal L., Ming Ding, and Mary V. Pratt. "Intraocular lens material evaluation by iris abrasion in vitro: A scanning electron microscope study." Journal of Cataract & Refractive Surgery 14, no. 5 (September 1988): 520–25. http://dx.doi.org/10.1016/s0886-3350(88)80009-9.

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Alexeeva, N. B. "Seed morphology in the genus Iris (Iridaceae) from Russia." VAVILOVIA 3, no. 1 (November 6, 2020): 5–28. http://dx.doi.org/10.30901/2658-3860-2020-1-5-28.

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The genus Iris in Russia is represented by 41 species. Four species are endemic, 11 are included in the Red Data Book of the Russian Federation and 30 have different regional conservation status. The presented results of the study of the morphology of seeds and of seed coat surface morphology in 40 species from the genus Iris growing in Russia were obtained mainly using light and scanning electron microscopy. Seed shape is round, ovate, oblong or pear‑shaped, with the exception for I. psammocola, in which it is club‑shaped. The smallest seeds in the studied species belong to I. ruthenica and I. uniflora. Morphometric data lead to interesting conclusions regarding the taxonomic relations between some species. For example, the species currently considered as synonyms, e.g., I. biglumis and I. pallasii in I. lactea, and I. maackii in I. pseudacorus, are found different concerning seed morphology. On the other hand, the taxonomically well distinct species such as I. halophila and I. pseudonotha share similar seed morphology. A study of the morphological characteristics of the seed coat surface in 40 species of the genus Iris made it possible to compile an atlas for determining species in the genus Iris in Russia.

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Fiolita, Kiki. "An Overview of The Eye Component (Iris, Lens and Retina) From Mackerel Female (Rastrelliger brachysoma)." BioScience 1, no. 1 (March 31, 2017): 30. http://dx.doi.org/10.24036/02017117189-0-00.

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Fish ability to exist and defend their lifeinvolve sense of sight beside sense or another receptors. One of thefactor that influence fish behavior is the sight sharpness. Which is influence by amount and cell formation of cone cells, rod cells, and eye lens diameter. In Indonesia, comprehension and study about the fish sight ability is still minimal in fact this study is very important for fishery technology development. This research aims to describeof theeye components (Iris, Lens, and Retina). This research observe the component eye mackerel female.This research is descriptive, that is reveals research object data actually. Research which observe the component of femalemackerelseye. Theeyes component which is taken is iris, lens, and retina, and the observation use Scanning Electron Microscope (SEM).The results indicate that iris structure of the fish contain a lot of melanosoms pigment. The lens have the rounds shape and transparant yellows color, the retina have cone cell and rod cell. The conecell from sided mozaik also have two cells types, singular and doubled cone cells. The is due to mackerel high intensity in using their sense of sight, ability to distinguish colors and including fish that actively hunt prey. Keywords Rastrellige brachysoma, the structure of fish eyes, photoreceptors.

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Lazzari, M., V. Franceschini, G. Minelli, and F. Ciani. "Choroidal and iris angioarchitecture of the newt: A scanning electron-microscopic study of vascular corrosion casts." Experientia 49, no. 4 (April 1993): 277–81. http://dx.doi.org/10.1007/bf01923401.

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Wei, Xianglei, Ling Cui, Zhenhuan Li, Wang Yi, Xu Chen, and Jinwei Ying. "Application of CT Image Scanning Technology Based on Iris Algorithm in Clinical Diagnosis of Patients with Hepatobiliary Stones." Journal of Medical Imaging and Health Informatics 11, no. 1 (January 1, 2021): 203–8. http://dx.doi.org/10.1166/jmihi.2021.3438.

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Objective: To investigate the value of multi-slice spiral CT in the diagnosis of extrahepatic bile duct stones using Iris algorithm. Methods: 66 cases of extrahepatic bile duct stones underwent plain and enhanced multiline spiral CT. Observe the density, size, location and number of stones during the plain scan. According to the venous phase enhanced scan, the extrahepatic bile duct wall ≥2 mm was used as the thickening criterion to evaluate the stone density, size, number, and composition ratio of the site and its relationship with tube wall thickening. Results: A total of 57 cases of stones of different densities were found on CT. Nine cases of stones of equal density were not identified. Among the 56 cases with thickened wall, 87.50% (49/56) were concentric and 12.50% (7/56) were eccentric. The wall thickening occurred 62.50% (35/56) below the stone; 17.86% (10/56) was located on the level or above the stone, and 8.93% (5/56) was above the stone. 6 cases (6/56) (10.71%) showed extensive tube wall thickening, all caused by multiple stones. Conclusion: In the study of extrahepatic bile duct stones using the Iris algorithm, it was found that most concentric circular tube wall thickening occurred on or below the stone level. When plain CT scan does not show clear bile duct stones, and this phenomenon appears in the portal vein phase of enhanced scan, the possibility of stones should be considered.

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Allen, David A., John R. Barton, Michael G. Burton, Helen Davies, Tony J. Farrell, Peter R. Gillingham, Allan F. Lankshear, et al. "IRIS: an Infrared Imager and Spectrometer for the Anglo-Australian Telescope." Publications of the Astronomical Society of Australia 10, no. 4 (1993): 298–309. http://dx.doi.org/10.1017/s1323358000025911.

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AbstractWe describe a versatile infrared camera/spectrograph, IRIS, designed and constructed at the Anglo-Australian Observatory for use on the Anglo-Australian Telescope. A variety of optical configurations can be selected under remote control to provide several direct image scales and a few low-resolution spectroscopic formats. Two cross-dispersed transmission echelles are of novel design, as is the use of a modified Bowen-Burch system to provide a fast f/ratio in the widest-field option. The drive electronics includes a choice of readout schemes for versatility, and continuous display when the array is not taking data, to facilitate field acquisition and focusing.The linearity of the detector has been studied in detail. Although outwardly good, slight nonlinearities prevent removal of fixed-pattern noise from the data without application of a cubic linearising function.Specific control and data-reduction software has been written. We describe also a scanning mode developed for spectroscopic imaging.

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Zhang, Jingwei, Dazhuang Huang, Xiaojie Zhao, Xueyan Hou, Dongliu Di, Shaokun Wang, Jinsen Qian, and Pai Sun. "Pollen morphology of different species of Iris barbata and its systematic significance with scanning electron microscopy methods." Microscopy Research and Technique 84, no. 8 (February 13, 2021): 1721–39. http://dx.doi.org/10.1002/jemt.23730.

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Bausch, Birke, Ann-Cathrin Koschker, Martin Fassnacht, Johanna Stoevesandt, Michael M. Hoffmann, Charis Eng, Bruno Allolio, and Hartmut P. H. Neumann. "Comprehensive Mutation Scanning of NF1 in Apparently Sporadic Cases of Pheochromocytoma." Journal of Clinical Endocrinology & Metabolism 91, no. 9 (September 1, 2006): 3478–81. http://dx.doi.org/10.1210/jc.2006-0780.

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Abstract Background: Pheochromocytoma is a rare manifestation in patients with neurofibromatosis type 1 (NF 1). The 57-exon susceptibility gene NF1 has so far not been systematically scanned for unexpected germline mutations in individuals with sporadic pheochromocytoma. Methods: Twenty-seven patients with bilateral adrenal and/or extraadrenal abdominal pheochromocytoma not carrying germline mutations of the genes VHL, RET, SDHB, and SDHD were selected from the European-American pheochromocytoma registry. All 57 exons and flanking intronic regions of the NF1 gene were PCR amplified using newly designed primer pairs to exclude the amplification of pseudogenes. Intragenic mutation scanning was performed using denaturing HPLC and bidirectional direct sequencing. Results: Of the 27 apparently sporadic cases, one (4%) was found to have a pathogenic germline NF1 mutation, Leu303Arg. Clinical reevaluation of this individual, who had bilateral pheochromocytoma, revealed classic, but very mild, features of NF 1, one cutaneous neurofibroma, axillary freckling, and Lisch nodules of the iris as well as a few café-au-lait spots. Conclusions: In the absence of germline mutations in VHL, RET, SDHD, and SDHB, patients with pheochromocytoma, especially with bilateral disease, should be checked thoroughly for clinical lesions suggestive of underlying syndromes such as the cutaneous and ophthalmological features characteristic of NF 1.

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Reyer, Randall W. "Macrophage mobilization and morphology during lens regeneration from the iris epithelium in newts: Studies with correlated scanning and transmission electron microscopy." American Journal of Anatomy 188, no. 4 (August 1990): 345–65. http://dx.doi.org/10.1002/aja.1001880403.

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Avram, Camelia, Jose Machado, and Adina Aştilean. "Hardware Passwords Manager Based on Biometric Authentication." Engineering Proceedings 6, no. 1 (May 17, 2021): 31. http://dx.doi.org/10.3390/i3s2021dresden-10085.

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This paper presents a portable passwords manager which has a two-stage biometric-based access procedure. Data security using biometric methods was chosen as a variant of reduced complexity but was very effective in preventing cyber theft. The implementation of biometrics for the purpose of identification in high-security systems has become essential with the evolution of technology and the spike in identity theft. Unlike passwords or IDs, a biometric feature is an identifier that cannot be lost, stolen, or replicated, which provides biometric authentication systems with an increased level of security. During the first accessing step, the 3DPassManager portable device measures the heartbeat and uses fingerprint and iris features to realize a unique biometric-based authentication. While the specific characteristics of fingerprint and iris features are integrated to ensure that the person using the device is the rightful owner, the pulse is utilized to verify if previously acquired static images are not used. During the second accessing step, a password is generated based on fingerprint details, valid only for a small-time interval. The fingerprint is stored in a secret key with a 1024-bit length. Once access is allowed, the passwords are made available through an extension installed on the web browser. The device is the size of a cigarette pack and communicates with the PC by scanning a QR code. It is safe and was previously tested for dictionary and brute force attacks.

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Packer, Mark, Stephen D. Klyce, and Craig Smith. "The LENSAR® Laser System–fs 3D for Femtosecond Cataract Surgery." US Ophthalmic Review 07, no. 02 (2014): 89. http://dx.doi.org/10.17925/usor.2014.07.02.89.

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The LENSAR® Laser System’s ergonomic design permits flexible functionality in any operating environment. Its low-pressure liquid interface eliminates corneal compression and facilitates accurate and complete capsulotomy construction. The Augmented Reality™ imaging system utilizes a variable super luminescent diode for scanning structured illumination to provide high-contrast, high-definition targets, which guide the laser. Real-time imaging adjustments compensate for minute degrees of tissue displacement, permitting unrivalled precision in corneal incision architecture. Precise laser spot application allows fragmentation of all grades of cataract, without the need for unnecessarily large safety margins. Iris registration compensates for cyclotorsion in the construction of arcuate incisions by aligning preoperative corneal biometry to intraoperative imaging. The ability to define the cataract grade intraoperatively facilitates efficient phacofragmentation by permitting surgeon-specified preset patterns for the full range of nuclear densities. The LENSAR Laser System represents the state of the art in femtosecond cataract surgery.

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Packer, Mark, Stephen D. Klyce, and Craig Smith. "The LENSAR® Laser System–fs 3D for Femtosecond Cataract Surgery." European Ophthalmic Review 08, no. 02 (2014): 93. http://dx.doi.org/10.17925/eor.2014.08.02.93.

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The LENSAR® Laser Systems ergonomic design permits flexible functionality in any operating environment. Its low-pressure liquid interface eliminates corneal compression and facilitates accurate and complete capsulotomy construction. The Augmented Reality imaging system utilises a variable super luminescent diode for scanning structured illumination to provide high-contrast, high-definition targets, which guide the laser. Real-time imaging adjustments compensate for minute degrees of tissue displacement, permitting unrivalled precision in corneal incision architecture. Precise laser spot application allows fragmentation of all grades of cataract, without the need for unnecessarily large safety margins. Iris registration compensates for cyclotorsion in the construction of arcuate incisions by aligning preoperative corneal biometry to intraoperative imaging. The ability to define the cataract grade intraoperatively facilitates efficient phacofragmentation by permitting surgeon-specified preset patterns for the full range of nuclear densities. The LENSAR Laser System represents the state of the art in femtosecond cataract surgery.

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Xin, Yang, Yi Liu, Zhi Liu, Xuemei Zhu, Lingshuang Kong, Dongmei Wei, Wei Jiang, and Jun Chang. "A survey of liveness detection methods for face biometric systems." Sensor Review 37, no. 3 (June 19, 2017): 346–56. http://dx.doi.org/10.1108/sr-08-2015-0136.

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Purpose Biometric systems are widely used for face recognition. They have rapidly developed in recent years. Compared with other approaches, such as fingerprint recognition, handwriting verification and retinal and iris scanning, face recognition is more straightforward, user friendly and extensively used. The aforementioned approaches, including face recognition, are vulnerable to malicious attacks by impostors; in such cases, face liveness detection comes in handy to ensure both accuracy and robustness. Liveness is an important feature that reflects physiological signs and differentiates artificial from real biometric traits. This paper aims to provide a simple path for the future development of more robust and accurate liveness detection approaches. Design/methodology/approach This paper discusses about introduction to the face biometric system, liveness detection in face recognition system and comparisons between the different discussed works of existing measures. Originality/value This paper presents an overview, comparison and discussion of proposed face liveness detection methods to provide a reference for the future development of more robust and accurate liveness detection approaches.

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Cummings, Vonda J., Abigail M. Smith, Peter M. Marriott, Bryce A. Peebles, and N. Jane Halliday. "Effect of reduced pH on physiology and shell integrity of juvenile Haliotis iris (pāua) from New Zealand." PeerJ 7 (September 25, 2019): e7670. http://dx.doi.org/10.7717/peerj.7670.

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The New Zealand pāua or black footed abalone, Haliotis iris, is one of many mollusc species at potential risk from ocean acidification and warming. To investigate possible impacts, juvenile pāua (~24 mm shell length) were grown for 4 months in seawater pH/pCO2 conditions projected for 2100. End of century seawater projections (pHT 7.66/pCO2 ~1,000 μatm) were contrasted with local ambient conditions (pHT 8.00/pCO2 ~400 μatm) at two typical temperatures (13 and 15 °C). We used a combination of methods (morphometric, scanning electron microscopy, X-ray diffraction) to investigate effects on juvenile survival and growth, as well as shell mineralogy and integrity. Lowered pH did not affect survival, growth rate or condition, but animals grew significantly faster at the higher temperature. Juvenile pāua were able to biomineralise their inner nacreous aragonite layer and their outer prismatic calcite layer under end-of-century pH conditions, at both temperatures, and carbonate composition was not affected. There was some thickening of the nacre layer in the newly deposited shell with reduced pH and also at the higher temperature. Most obvious was post-depositional alteration of the shell under lowered pH: the prismatic calcite layer was thinner, and there was greater etching of the external shell surface; this dissolution was greater at the higher temperature. These results demonstrate the importance of even a small (2 °C) difference in temperature on growth and shell characteristics, and on modifying the effects at lowered pH. Projected CO2-related changes may affect shell quality of this iconic New Zealand mollusc through etching (dissolution) and thinning, with potential implications for resilience to physical stresses such as predation and wave action.

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Venegas, Pablo J., Luis A. García-Ayachi, Lourdes Y. Echevarría, Daniel J. Paluh, Juan C. Chávez–Arribasplata, Axel Marchelie, and Alessandro Catenazzi. "A new species of marsupial frog (Anura; Gastrotheca) from the Cordillera de Colán in northeastern Peru." Vertebrate Zoology 71 (April 9, 2021): 201–18. http://dx.doi.org/10.3897/vz.71.e60097.

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We describe a new species of marsupial frog, genus Gastrotheca, using morphological characters and molecular data as lines of evidence. The new species was discovered in the páramo and the ecotone between páramo and humid montane forest of Cordillera de Colán, at elevations between 3136 and 3179 m a.s.l., in northeastern Peru. The new species is distinguished from all its congeners by the combination of the following characters: coarsely granular skin on dorsum, a green dorsal coloration without pattern, finger I shorter than finger II, turquoise iris, and a venter without blotches, flecks or dots. Furthermore, we include a detailed osteological description of the new Gastrotheca species based on Micro-CT scanning. Based on our phylogenetic analyses, the new species belongs to the Gastrotheca marsupiata species group, is sister to G. oresbios and closely related to G. psychrophila, G. spectabilis, G. stictopleura and one undescribed species. Additionally, we test for the presence of the fungal pathogen Batrachochytrium dendrobatidis (Bd). No Bd infection was detected for G. gemma sp. nov. specimens but Bd prevalence was detected among syntopic frogs.

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Seong, Daewoon, Sangyeob Han, Jaeyul Lee, Euimin Lee, Yoonseok Kim, Junsoo Lee, Mansik Jeon, and Jeehyun Kim. "Waterproof Galvanometer Scanner-Based Handheld Photoacoustic Microscopy Probe for Wide-Field Vasculature Imaging In Vivo." Photonics 8, no. 8 (July 30, 2021): 305. http://dx.doi.org/10.3390/photonics8080305.

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Photoacoustic imaging (PAI) is a hybrid non-invasive imaging technique used to merge high optical contrast and high acoustic resolution in deep tissue. PAI has been extensively developed by utilizing its advantages that include deep imaging depth, high resolution, and label-free imaging. As a representative implementation of PAI, photoacoustic microscopy (PAM) has been used in preclinical and clinical studies for its micron-scale spatial resolution capability with high optical absorption contrast. Several handheld and portable PAM systems have been developed that improve its applicability to several fields, making it versatile. In this study, we developed a laboratory-customized, two-axis, waterproof, galvanometer scanner-based handheld PAM (WP-GVS-HH-PAM), which provides an extended field of view (14.5 × 9 mm2) for wide-range imaging. The fully waterproof handheld probe enables free movement for imaging regardless of sample shape, and volume rate and scanning region are adjustable per experimental conditions. Results of WP-GVS-HH-PAM-based phantom and in vivo imaging of mouse tissues (ear, iris, and brain) confirm the feasibility and applicability of our system as an imaging modality for various biomedical applications.

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Wasserman, Arthur J., Y. Pedro Kato, and Frederick H. Silver. "A simple method for exposing and examining the interior of fragile biological materials." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 3 (August 12, 1990): 858–59. http://dx.doi.org/10.1017/s0424820100161850.

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Examining the inside of delicate and fragile dry biomaterials is difficult because they are vulnerable to mechanical damage. Compression and sheering of a sample during exposure of the interior can produce artifacts making interpretation of the ultrastructure difficult. In this report a simple method for exposing and retaining the interior substructure of delicate specimens and mounting them for scanning electron microscopic (SEM) observation is described.Collagen fibers were prepared as described previously. In brief, 1% collagen dispersion, prepared from bovine hide, was extruded through polyethylene tubing with an inner diameter of 0.28 mm into a 37°C, pH 7.5, fiber formation buffer. After 45 mins in the buffer, the fibers were rinsed in isopropyl alcohol for 4 hrs followed by distilled water for 20 mins. The fibers were then crosslinked.The interior of collagen fibers were exposed by deep freezing 1 cm segments of fiber in liquid nitrogen. Using iris scissors the first and last piece of each segment (which contained ends previously exposed to the atmosphere) were snapped away and discarded. Each frozen segment was then snapped in half. By this method each half of the original 1 cm segment had a freshly cleaved top and bottom surface. The segments were transferred to an aluminum foil pouch (in liquid nitrogen).

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Buckenham Boyle, Alexander, Soobin Namkung, William Shew, Akilesh Gokul, Charles N. J. McGhee, and Mohammed Ziaei. "Repeatability and agreement of white-to-white measurements between slit-scanning tomography, infrared biometry, dual rotating Scheimpflug camera/Placido disc tomography, and swept source anterior segment optical coherence tomography." PLOS ONE 16, no. 7 (July 16, 2021): e0254832. http://dx.doi.org/10.1371/journal.pone.0254832.

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Purpose To assess the agreement and repeatability of horizontal visible iris diameter (HVID) or white-to-white (WTW) measurements between four imaging modalities; combination slit scanning elevation/Placido tomography, infrared biometry, dual rotating scheimpflug camera/Placido tomography, and swept source anterior segment optical coherence tomography (AS-OCT). Methods A prospective study of 35 right eyes of healthy volunteers were evaluated using the Orbscan IIz, IOL Master 700, Galilei G2, and DRI Triton OCT devices. The inter-device agreement and repeatability of HVID/WTW measurements for each device were analysed. Results Mean HVID/WTW values obtained by the Orbscan IIz, IOL Master 700, Galilei G2 and DRI Triton OCT were 11.77 ± 0.40 mm, 12.40 ± 0.43 mm, 12.25 ± 0.42 mm, and 12.42 ± 0.47 mm, respectively. All pairwise comparisons revealed statistically significant differences in mean HVID/WTW measurements (p = <0.01) except for the IOL Master 700—DRI OCT Triton pair (p = 0.56). Mean differences showed that the DRI Triton OCT produced the highest HVID/WTW values, followed by the IOL Master 700, Galilei G2 and Orbscan IIz, respectively. The limits of agreement were large on all device pairs. There was high repeatability for all devices (ICC ≥ 0.980). The highest repeatability was seen in the Galilei G2 (ICC = 0.995) and lowest in the Orbscan IIz (ICC = 0.980). Conclusions The four devices exhibit high repeatability, but should not be used interchangeably for HVID/WTW measurements in clinical practice.

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Salman, Jad, Cayla A. Stifler, Alireza Shahsafi, Chang-Yu Sun, Stephen C. Weibel, Michel Frising, Bryan E. Rubio-Perez, et al. "Hyperspectral interference tomography of nacre." Proceedings of the National Academy of Sciences 118, no. 15 (April 8, 2021): e2023623118. http://dx.doi.org/10.1073/pnas.2023623118.

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Structural characterization of biologically formed materials is essential for understanding biological phenomena and their enviro-nment, and for generating new bio-inspired engineering concepts. For example, nacre—the inner lining of some mollusk shells—encodes local environmental conditions throughout its formation and has exceptional strength due to its nanoscale brick-and-mortar structure. This layered structure, comprising alternating transparent aragonite (CaCO3) tablets and thinner organic polymer layers, also results in stunning interference colors. Existing methods of structural characterization of nacre rely on some form of cross-sectional analysis, such as scanning or transmission electron microscopy or polarization-dependent imaging contrast (PIC) mapping. However, these techniques are destructive and too time- and resource-intensive to analyze large sample areas. Here, we present an all-optical, rapid, and nondestructive imaging technique—hyperspectral interference tomography (HIT)—to spatially map the structural parameters of nacre and other disordered layered materials. We combined hyperspectral imaging with optical-interference modeling to infer the mean tablet thickness and its disorder in nacre across entire mollusk shells from red and rainbow abalone (Haliotis rufescens and Haliotis iris) at various stages of development. We observed that in red abalone, unexpectedly, nacre tablet thickness decreases with age of the mollusk, despite roughly similar appearance of nacre at all ages and positions in the shell. Our rapid, inexpensive, and nondestructive method can be readily applied to in-field studies.

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Patel, Palak. "Signature Verification Using Artificial Neural Network." International Journal of Advanced Research in Computer Science and Software Engineering 7, no. 12 (January 3, 2018): 40. http://dx.doi.org/10.23956/ijarcsse.v7i12.494.

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The human signature is most important for access. Signature of the person is important biometric attribute of a human being which is used to authenticate human identity. There are many biometric characteristics by which one can have own identity like face recognition, fingerprint detection, iris inspection and retina scanning. In non-vision based techniques voice recognition and signature verification are most widely used. Verification can be performed either Online or Offline. Online system of signature verification uses dynamic information of a signature captured at the time the signature is made. Offline system uses scanned image of signature. In this paper, I present a method for Offline Verification of signatures using a set of simple shape based geometric features. As signatures play an important role in financial, commercial and legal transactions, truly secured authentication becomes more and more crucial. This paper presents the off-line signature recognition & verification using neural network in which the human signature is captured and presented in the image format. Various image processing techniques are used to recognize and verify the signature. Preprocessing of a scanned image is necessary to isolate the signature part and to remove any spurious noise present. Initially system use database of signatures obtained from those individuals whose signatures have to be authenticated by the system. Then artificial neural network (ANN) is used to verify and classify the signatures. The implementation details and results are discussed in the paper.

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Furuya, Toshie, and Kenji Kashiwagi. "Longitudinal Change in Peripheral Anterior Chamber Depth of Eyes with Angle Closure after Laser Iridotomy." Journal of Ophthalmology 2018 (December 24, 2018): 1–7. http://dx.doi.org/10.1155/2018/9106247.

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Purpose. To investigate longitudinal changes in peripheral anterior chamber depth (pACD) of eyes with angle closure after laser iridotomy (LI) and factors related to prognosis. Design. Retrospective cohort study. Methods. Eyes with primary angle closure (PAC), acute PAC, or chronic angle closure glaucoma (CACG) that underwent LI (LI group) and eyes that underwent phacoemulsification and intraocular lens insertion (PEA + IOL group) were employed. Longitudinal changes in pACD were evaluated with a scanning peripheral anterior chamber depth analyzer (SPAC) in addition to routine ophthalmic examination. Results. Forty-eight eyes of LI groups (69.8 ± 8.5 years) and 21 eyes of PEA + IOL group (65.6 ± 12.7 years) were enrolled. Mean follow-up times of LI group and PEA + IOL group were 43.4 ± 12.7 months and 36.5 ± 2.5 months, respectively. LI significantly increased pACD as indicated by the SPAC grade change from 3.8 ± 1.1 to 4.6 ± 1.2 (p<0.001). However, SPAC grade was gradually reduced and reached the pre-LI level by the third year of follow up. PEA + IOL also significantly increased SPAC grade from 6.7 ± 1.6 to 8.7 ± 2.0 (p<0.001), but no time-related change was observed. Twenty-three cases of LI group presented with deterioration of glaucoma control. The type of angle closure, plateau iris configuration, peripheral anterior synechia, and glaucomatous visual field defects were significantly associated with prognosis of glaucoma after LI. Conclusions. Peripheral ACD is temporarily deepened by LI, but returns to the pre-LI level in approximately three years. The type of angle closure and some factors may be related to glaucoma prognosis after LI.

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Astakhov, Yuriy Sergeyevich, Yevgeniy Vladimirovich Butin, Nataliya Vladimirovna Morozova, Vitaliy Olegovich Sokolov, and Svetlana Sergeevna Florentseva. "The coloboma of the choroid simulating optic nerve duplication." Ophthalmology journal 6, no. 2 (June 15, 2013): 67–74. http://dx.doi.org/10.17816/ov2013267-74.

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In the article, a coloboma of the choroid is described simulating optic disc duplicaton as well as modern possibilities of instrumental work-up methods, which allowed to make a diagnosis. A coloboma (from the Greek koloboma, meaning defect) — is a defect of lid tissues, iris, choroid or optic nerve. A coloboma may be сongenital or acquired. A typical coloboma of the choroid is localized in the lower part of the eye fundus. At times, it comes down to the optic disc, and sometimes involves it as well. The white color of the defect is due to the show-through of the sclera, because the choroid here is completely absent. Corresponding to the coloboma of the choroid, the retina is hypoplastic or absent at times. An optic disc duplication — at this anomaly there are two optic discs on the eye fundus. Sometimes, both may be phtitical and hypoplastic, but more often one of them is hypoplastic, and the second one is performing its function. A true optic disc duplication comes out of the optic nerve partition into 2 or more fascicles. The duplicated optic nerve is pointed out by two optic foramens in one orbit by radiographic analysis, two blind spots in the visual field of one eye, simultaneous central retinal artery pulsation on both optic discs. Ultrasonic B-scanning or OCT and MRI may confirm the existence of a true optic nerve and optic disc duplication. A pseudo-duplication of the optic disc is also very rare and represents a well delineated defect, close to the normal optic disc and simulating an ancillary optic disc with an adjoining area of chorioretinal atrophy.

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Milstrey, Alexander, Steffen Rosslenbroich, Jens Everding, Michael J. Raschke, Robert Geoff Richards, Thomas Fintan Moriarty, and Jan Puetzler. "Antibiofilm efficacy of focused high-energy extracorporeal shockwaves and antibiotics in vitro." Bone & Joint Research 10, no. 1 (January 1, 2021): 77–84. http://dx.doi.org/10.1302/2046-3758.101.bjr-2020-0219.r1.

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Aims Biofilm formation is one of the primary reasons for the difficulty in treating implant-related infections (IRIs). Focused high-energy extracorporeal shockwave therapy (fhESWT), which is a treatment modality for fracture nonunions, has been shown to have a direct antibacterial effect on planktonic bacteria. The goal of the present study was to investigate the effect of fhESWT on Staphylococcus aureus biofilms in vitro in the presence and absence of antibiotic agents. Methods S. aureus biofilms were grown on titanium discs (13 mm × 4 mm) in a bioreactor for 48 hours. Shockwaves were applied with either 250, 500, or 1,000 impulses onto the discs surrounded by either phosphate-buffered saline or antibiotic (rifampin alone or in combination with nafcillin). The number of viable bacteria was determined by quantitative culture after sonication. Representative samples were taken for scanning electron microscopy. Results The application of fhESWT led to a ten-fold reduction in bacterial counts on the metal discs for all impulse numbers compared to the control (p < 0.001). Increasing the number of impulses did not further reduce bacterial counts in the absence of antibiotics (all p > 0.289). Antibiotics alone reduced the number of bacteria on the discs; however, the combined application of the fhESWT and antibiotic administration further reduced the bacterial count compared to the antibiotic treatment only (p = 0.032). Conclusion The use of fhESWT significantly reduced the colony-forming unit (CFU) count of a S. aureus biofilm in our model independently, and in combination with antibiotics. Therefore, the supplementary application of fhESWT could be a helpful tool in the treatment of IFIs in certain cases, including infected nonunions. Cite this article: Bone Joint Res 2021;10(1):77–84.

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Muratib, Fizah, Yuya Mizuno, Ines Carreira Figueiredo, Oliver Howes, and Tiago Reis Marques. "Dissection of neuroinflammation in schizophrenia." BJPsych Open 7, S1 (June 2021): S274—S275. http://dx.doi.org/10.1192/bjo.2021.730.

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AimsSchizophrenia is notoriously becoming one of the world's most debilitating mental disorders, affecting 1 in 100 people. There is increasing evidence that neuroinflammation plays a part in the pathogenesis of schizophrenia and other psychotic disorders; microglial activity acting as a marker for neuroinflammatory reactions in the brain. Furthermore, cannabis is an illicit substance that also evokes a similar response in the neuroimmune activity. This project explores how cannabis exposure influences an elevation in neuroinflammatory responses through TSPO levels, and whether this information can help us determine if cannabis use and increased TSPO levels can be associated with a risk factor for developing psychosis.Method55 participants (36 males and 19 females) were recruited from the community by the IRIS (Inflammatory Reaction in Schizophrenia) team at the IoPPN, King's College London, from which 34 patients with a diagnosis of schizophrenia and 21 healthy controls took part in the study. The eligible participants underwent clinical assessments and PET scanning, from which cannabis use history and PET data were collected. Participant neuroinflammatory levels are represented by [18F]DPA-714 volume and different regions of grey matter in the brain were analysed through multivariate analyses, the confounding variables being age and TSPO genotype.ResultA statistically significant association is shown between participants who have had exposure to cannabis and participants who have not had any exposure in their lifetime. The differences across the prioritised brain regions of interest were robust, the association appearing more apparent and statistically significant in the total (p = .00) and temporal grey matter (p = .00) regions of the brain. This may suggest that cannabis exposure influences the [18F]DPA-714 VT in the significant regions of interest. However, a negative association is seen with current use, the quantity of use, and the frequency of use.ConclusionThe initial findings for cannabis exposure show us a positive association with increased TSPO levels, however, limitations must be taken into account. Although we cannot readily establish that elevated TSPO levels in cannabis users can presently act as a risk factor marker for developing psychosis from this particular study, we can utilise this data to continue our research in disclosing a new system to predict the occurrence of psychosis.

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McMullan, D. "Scanning electron microscopy 1928-1965." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 762–63. http://dx.doi.org/10.1017/s0424820100149647.

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The beginning of the general use of the scanning electron microscope (SEM) can be accurately dated to 1965 when the Cambridge Instrument Company in the U.K. marketed their Stereoscan 1 SEM (to be followed about 6 months later by JEOL in Japan). But development had been in progress intermittently over the previous 30 years in Germany, the U.S.A., France, and the U.K. where in 1948 work was begun in Charles Oatley’s department at the Cambridge University Engineering Department which led directly to the Stereoscan. The purpose of this paper is to trace the development of the SEM and to show that some of the ideas pul forward by the early workers were well ahead of their time and only became technologically practicable much later.The First proposal for the application of scanning to microscopy was made in 1928 by Synge, an Irish scientific dilettante, who conceived the near-field scanning optical microscope but did not attempt to build one.

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Ochs, Kerstin, RenéC Rust, and Michael Niepmann. "Translation Initiation Factor eIF4B Interacts with a Picornavirus Internal Ribosome Entry Site in both 48S and 80S Initiation Complexes Independently of Initiator AUG Location." Journal of Virology 73, no. 9 (September 1, 1999): 7505–14. http://dx.doi.org/10.1128/jvi.73.9.7505-7514.1999.

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ABSTRACT Most eukaryotic initiation factors (eIFs) are required for internal translation initiation at the internal ribosome entry site (IRES) of picornaviruses. eIF4B is incorporated into ribosomal 48S initiation complexes with the IRES RNA of foot-and-mouth disease virus (FMDV). In contrast to the weak interaction of eIF4B with capped cellular mRNAs and its release upon entry of the ribosomal 60S subunit, eIF4B remains tightly associated with the FMDV IRES during formation of complete 80S ribosomes. Binding of eIF4B to the IRES is energy dependent, and binding of the small ribosomal subunit to the IRES requires the previous energy-dependent association of initiation factors with the IRES. The interaction of eIF4B with the IRES in 48S and 80S complexes is independent of the location of the initiator AUG and thus independent of the mechanism by which the small ribosomal subunit is placed at the actual start codon, either by direct internal ribosomal entry or by scanning. eIF4B does not greatly rearrange its binding to the IRES upon entry of the ribosomal subunits, and the interaction of eIF4B with the IRES is independent of the polypyrimidine tract-binding protein, which enhances FMDV translation.

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Ochs, Kerstin, Lanja Saleh, Gergis Bassili, Volker H. Sonntag, Amandus Zeller, and Michael Niepmann. "Interaction of Translation Initiation Factor eIF4B with the Poliovirus Internal Ribosome Entry Site." Journal of Virology 76, no. 5 (March 1, 2002): 2113–22. http://dx.doi.org/10.1128/jvi.76.5.2113-2122.2002.

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ABSTRACT Poliovirus translation is initiated at the internal ribosome entry site (IRES). Most likely involving the action of standard initiation factors, this highly structured cis element in the 5" noncoding region of the viral RNA guides the ribosome to an internal silent AUG. The actual start codon for viral protein synthesis further downstream is then reached by ribosomal scanning. In this study we show that two of the secondary structure elements of the poliovirus IRES, domain V and, to a minor extent, domain VI, are the determinants for binding of the eukaryotic initiation factor eIF4B. Several mutations in domain V which are known to greatly affect poliovirus growth also seriously impair the binding of eIF4B. The interaction of eIF4B with the IRES is not dependent on the presence of the polypyrimidine tract-binding protein, which also binds to the poliovirus IRES. In contrast to its weak interaction with cellular mRNAs, eIF4B remains tightly associated with the poliovirus IRES during the formation of complete 80S ribosomes. Binding of eIF4B to the IRES is energy dependent, and binding of the small ribosomal subunit to the IRES requires the previous energy-dependent association of initiation factors with the IRES. These results indicate that the interaction of eIF4B with the 3" region of the poliovirus IRES may be directly involved in translation initiation.

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Xiao, Ming, Yujing Wang, Zailing Zhu, Jialin Yu, Lingzhu Wan, and Jun Chen. "Influence of NS5A protein of classical swine fever virus (CSFV) on CSFV internal ribosome entry site-dependent translation." Journal of General Virology 90, no. 12 (December 1, 2009): 2923–28. http://dx.doi.org/10.1099/vir.0.014472-0.

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An internal ribosome entry site (IRES) present in the 5′ untranslated region (UTR) promotes translation of classical swine fever virus (CSFV) genomes. Using an in vitro system with monocistronic reporter RNA containing the CSFV 5′UTR, this study found that CSFV NS5A decreased CSFV IRES-mediated translation in a dose-dependent manner. Deletion analysis showed that the region responsible for repressing CSFV IRES activity might cover aa 390–414, located in the C-terminal half of CSFV NS5A. Triple and single alanine-scanning mutagenesis revealed that the inhibitory effect on CSFV IRES-directed translation mapped to the K399, T401, E406 and L413 residues of NS5A. These important amino acids were also found to be present in the NS5A proteins of bovine viral diarrhea virus (BVDV)-1, BVDV-2, border disease virus and hepatitis C virus, indicating that NS5A may play an important role in the switch from translation to replication in these viruses.

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Rahmagiarti, Cintera, Silvia Tri Widyaningtyas, and Budiman Bela. "Konstruksi Plasmid Rekombinan untuk Inisiasi Translasi Enhance Green Fluorescent Protein oleh Internal Ribosomal Entry Site HIV-1." Media Penelitian dan Pengembangan Kesehatan 28, no. 2 (October 17, 2018): 67–72. http://dx.doi.org/10.22435/mpk.v28i2.181.

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Human immunodeficiency virus (HIV) is a virus that causes acquired immunodeficiency virus syndrome (AIDS). The HIV genome has a cap structure at 5’ and polyadenylation at 3’ on mRNA resulting in a translation initiation through scanning at 5'untranslated region (UTR). The Vpr protein produced during viral replication causes the 5'cap scanning to be inhibited so HIV-1 can directly recruit the ribosome at the start codon via internal ribosomal entry site (IRES). IRES activity is high at G2/M phase and highest expression in monocyte cell line (THP-1) and lymphocyte (HPB-ALL). The role of HIV IRES however, is not yet known in infection of nondividing cells by HIV-1. HIV-1 IRES and egfp from pcDNA5FRT/TO were amplified with PCR. The insert DNA (HIV-1 IRES_egfp) and pcDNA3.1(+) were digested with EcoRI and ApaI and then ligated. The verification was performed with PCR colonies, restriction verification, and sequencing. The size of insert DNA is 1067 bp while the vector is 5379 bp. E. coli transformed with DNA ligation produces 70 colonies, control of ligation produces 5 colonies, and negative control didn’t grow. 19 colonies contain recombinant DNA, restriction verification was of the appropriate size, and the sequence verification didn’t find any mutation. Therefore, the subcloning process pcDNA3.1_IRES HIV-1_egfp was successfully performed. Abstrak Human immunodeficiency virus (HIV) merupakan virus penyebab acquired immunodeficiency virus syndrome (AIDS). Genom HIV memiliki struktur cap di 5’ dan poliadenilasi di 3’ mRNA sehingga proses inisiasi translasi melalui pemindaian 5’cap pada struktur untranslated region (UTR) di 5’ mRNA HIV. Protein Vpr yang dihasilkan selama replikasi virus menyebabkan pemindaian melalui 5’cap terhambat sehingga HIV-1 dapat langsung merekrut ribosom pada kodon awal translasi melalui struktur internal ribosomal entry site (IRES). Aktivitas IRES tinggi pada fase G2/M dan ekspresi gen tinggi pada sel line monosit (THP-1) dan limfosit (HPB-ALL). Namun, peran IRES HIV-1 belum diketahui pada sel tidak membelah yang merupakan sel target pada infeksi HIV-1. DNA sekuen IRES HIV-1 dan egfp dari pcDNA5FRT/TO diamplifikasi dengan PCR. DNA sisipan (IRES HIV-1_egfp) dan pcDNA3.1(+) dipotong dengan EcoRI dan ApaI lalu DNA sisipan diligasi dengan pcDNA3.1(+). Verifikasi hasil klona dilakukan dengan PCR koloni, verifikasi restriksi, dan sekuensing. Restriksi DNA sisipan menghasilkan pita berukuran 1067 pb. Restriksi vektor plasmid menghasilkan pita berukuran 5379 pb. E.coli yang ditransformasi DNA ligasi menghasilkan 70 koloni, kontrol ligasi 5 koloni, dan kontrol negatif tidak tumbuh. 19 koloni terverifikasi mengandung DNA rekombinan, verifikasi restriksi memiliki ukuran sesuai, dan verifikasi sekuensing tidak terdapat perubahan basa. Oleh karena itu, proses subkloning pcDNA3.1_IRES HIV-1_egfp berhasil dilakukan.

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Johnson, Alex G., Rosslyn Grosely, Alexey N. Petrov, and Joseph D. Puglisi. "Dynamics of IRES-mediated translation." Philosophical Transactions of the Royal Society B: Biological Sciences 372, no. 1716 (March 19, 2017): 20160177. http://dx.doi.org/10.1098/rstb.2016.0177.

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Viral internal ribosome entry sites (IRESs) are unique RNA elements, which use stable and dynamic RNA structures to recruit ribosomes and drive protein synthesis. IRESs overcome the high complexity of the canonical eukaryotic translation initiation pathway, often functioning with a limited set of eukaryotic initiation factors. The simplest types of IRESs are typified by the cricket paralysis virus intergenic region (CrPV IGR) and hepatitis C virus (HCV) IRESs, both of which independently form high-affinity complexes with the small (40S) ribosomal subunit and bypass the molecular processes of cap-binding and scanning. Owing to their simplicity and ribosomal affinity, the CrPV and HCV IRES have been important models for structural and functional studies of the eukaryotic ribosome during initiation, serving as excellent targets for recent technological breakthroughs in cryogenic electron microscopy (cryo-EM) and single-molecule analysis. High-resolution structural models of ribosome : IRES complexes, coupled with dynamics studies, have clarified decades of biochemical research and provided an outline of the conformational and compositional trajectory of the ribosome during initiation. Here we review recent progress in the study of HCV- and CrPV-type IRESs, highlighting important structural and dynamics insights and the synergy between cryo-EM and single-molecule studies. This article is part of the themed issue ‘Perspectives on the ribosome’.

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Terenin, Ilya M., Sergei E. Dmitriev, Dmitri E. Andreev, Elizabeth Royall, Graham J. Belsham, Lisa O. Roberts, and Ivan N. Shatsky. "A Cross-Kingdom Internal Ribosome Entry Site Reveals a Simplified Mode of Internal Ribosome Entry." Molecular and Cellular Biology 25, no. 17 (September 1, 2005): 7879–88. http://dx.doi.org/10.1128/mcb.25.17.7879-7888.2005.

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ABSTRACT Rhopalosiphum padi virus (RhPV) is an insect virus of the Dicistroviridae family. Recently, the 579-nucleotide-long 5′ untranslated region (UTR) of RhPV has been shown to contain an internal ribosome entry site (IRES) that functions efficiently in mammalian, plant, and insect in vitro translation systems. Here, the mechanism of action of the RhPV IRES has been characterized by reconstitution of mammalian 48S initiation complexes on the IRES from purified components combined with the toeprint assay. There is an absolute requirement for the initiation factors eIF2 and eIF3 and the scanning factor eIF1 to form 48S complexes on the IRES. In addition, eIF1A, eIF4F (or the C-terminal fragment of eIF4G), and eIF4A strongly stimulated the assembly of this complex, whereas eIF4B had no effect. Although the eIF4-dependent pathway is dominant in the RhPV IRES-directed cell-free translation, omission of either eIF4G or eIF4A or both still allowed the assembly of 48S complexes from purified components with ∼23% of maximum efficiency. Deletions of up to 100 nucleotides throughout the 5′-UTR sequence produced at most a marginal effect on the IRES activity, suggesting the absence of specific binding sites for initiation factors. Only deletion of the U-rich unstructured 380-nucleotide region proximal to the initiation codon resulted in a complete loss of the IRES activity. We suggest that the single-stranded nature of the RhPV IRES accounts for its strong but less selective potential to bind key mRNA recruiting components of the translation initiation apparatus from diverse origins.

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Stein, Ilan, Ahuva Itin, Paz Einat, Rami Skaliter, Zehava Grossman, and Eli Keshet. "Translation of Vascular Endothelial Growth Factor mRNA by Internal Ribosome Entry: Implications for Translation under Hypoxia." Molecular and Cellular Biology 18, no. 6 (June 1, 1998): 3112–19. http://dx.doi.org/10.1128/mcb.18.6.3112.

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ABSTRACT Vascular endothelial growth factor (VEGF) is a hypoxia-inducible angiogenic growth factor that promotes compensatory angiogenesis in circumstances of oxygen shortage. The requirement for translational regulation of VEGF is imposed by the cumbersome structure of the 5′ untranslated region (5′UTR), which is incompatible with efficient translation by ribosomal scanning, and by the physiologic requirement for maximal VEGF production under conditions of hypoxia, where overall protein synthesis is compromised. Using bicistronic reporter gene constructs, we show that the 1,014-bp 5′UTR of VEGF contains a functional internal ribosome entry site (IRES). Efficient cap-independent translation is maintained under hypoxia, thereby securing efficient production of VEGF even under unfavorable stress conditions. To identify sequences within the 5′UTR required for maximal IRES activity, deletion mutants were analyzed. Elimination of the majority (851 nucleotides) of internal 5′UTR sequences not only maintained full IRES activity but also generated a significantly more potent IRES. Activity of the 163-bp long “improved” IRES element was abrogated, however, following substitution of a few bases near the 5′ terminus as well as substitutions close to the translation start codon. Both the full-length 5′UTR and its truncated version function as translational enhancers in the context of a monocistronic mRNA.

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Oumard, A., M. Hennecke, H. Hauser, and M. Nourbakhsh. "Translation of NRF mRNA Is Mediated by Highly Efficient Internal Ribosome Entry." Molecular and Cellular Biology 20, no. 8 (April 15, 2000): 2755–59. http://dx.doi.org/10.1128/mcb.20.8.2755-2759.2000.

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ABSTRACT The ubiquitous transcription factor NRF (NF-κB repressing factor) is a constitutive transcriptional silencer of the multifunctional cytokine interferon-β. NRF mRNA contains a long 5′ untranslated region (5′UTR) predicted to fold into a strong secondary structure. The presence of stable hairpins is known to be incompatible with efficient translation by ribosomal scanning. Using dicistronic reporter gene constructs, we show that the NRF 5′UTR acts as an internal ribosome entry site (IRES) which directs ribosomes to the downstream start codon by a cap-independent mechanism. The relative activity of this IRES in various cell lines is at least 30-fold higher than that of picornaviral IRESs. The NRF 5′UTR also functions as a translational enhancer in the context of monocistronic mRNAs. Our results indicate that the NRF 5′UTR contains a highly potent IRES, which may allow for an alternate mode of translation under physiological conditions in which cap-dependent translation is inhibited.

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Shi, Yijiang, Joseph Gera, and Alan Lichtenstein. "Interleukin-6 (IL-6) Enhances C-MYC Translation IN MULTIPLE MYELOMA (MM) CELLS: ROLE of IL-6-INDUCED EFFECTS On the C-MYC RNA-Binding PROTEIN, HNRNPA1." Blood 114, no. 22 (November 20, 2009): 3839. http://dx.doi.org/10.1182/blood.v114.22.3839.3839.

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Abstract Abstract 3839 Poster Board III-775 Our previous work (Cancer Research 68:10215, 2008) demonstrated that IL-6 enhanced c-myc protein expression in MM cells and function of the RNA-binding protein, hnRNPA1 (A1), was required. This occurred by way of enhanced cap-independent translation mediated via the internal ribosome entry site (IRES) in the 5'UTR of the myc RNA. IRES-dependent translation is the fail safe mechanism for protein expression when cap-dependent translation is suppressed by mTOR inhibition (with curtailed RNA cap-ribosome binding) and is especially important when an mRNA leader is relatively long and highly structured, such that scanning ribosomes are unlikely to efficiently initiate translation. The IRES directly recruits the ribosome to within close proximity to the start codon, bypassing the need for cap binding and ribosome scanning. HNRNPA1 (A1) is a documented IRES trans-acting factor (ITAF) for the myc IRES, facilitating translation but how its effects are enhanced by IL-6 is unknown. HNRNPA1 is a shuttling protein which binds the myc RNA in the nucleus and transports it to the cytoplasm. Initial experiments demonstrated that IL-6 stimulation of ANBL-6 and OCI-My5 MM cell lines, as well as several primary MM specimens, significantly increased the cytoplasmic localization of A1. To test if this enhanced cytoplasmic localization was critical, we stably expressed a dominant negative (DN) A1 gene that is incapable of nuclear-to-cytoplasmic shuttling and which also prevents endogenous hnRNPA1 shuttling. The DN also prevented A1-mediated transport of the shuttling protein, FUS. Expression of the DN in ANBL-6 cells prevented IL-6-induced effects on myc expression and on ANBL-6 cell growth. We also tested if IL-6 treatment affected A1 binding to the myc RNA by immunoprecipitating A1 and performing real time PCR on the immunoprecipitate for myc RNA levels. A significant increase in A1-myc RNA binding was confirmed. Mass spectroscopy demonstrated that IL-6 induced phosphorylation of A1 in its RNA-binding domain, which possibly mediated the enhanced binding. These results demonstrate that, by enhanced binding of the myc ITAF, hnRNPA1, to the myc IRES, and by enhanced transport of the complex to the translationally active cytoplasmic subcellular site, IL-6 may stimulate c-myc translation and subsequent MM cell growth. Disclosures: No relevant conflicts of interest to declare.

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Abaeva, Irina S., Tatyana V. Pestova, and Christopher U. T. Hellen. "Attachment of ribosomal complexes and retrograde scanning during initiation on the Halastavi árva virus IRES." Nucleic Acids Research 44, no. 5 (January 17, 2016): 2362–77. http://dx.doi.org/10.1093/nar/gkw016.

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Huez, Isabelle, Laurent Créancier, Sylvie Audigier, Marie-Claire Gensac, Anne-Catherine Prats, and Hervé Prats. "Two Independent Internal Ribosome Entry Sites Are Involved in Translation Initiation of Vascular Endothelial Growth Factor mRNA." Molecular and Cellular Biology 18, no. 11 (November 1, 1998): 6178–90. http://dx.doi.org/10.1128/mcb.18.11.6178.

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ABSTRACT The mRNA of vascular endothelial growth factor (VEGF), the major angiogenic growth factor, contains an unusually long (1,038 nucleotides) and structured 5′ untranslated region (UTR). According to the classical translation initiation model of ribosome scanning, such a 5′ UTR is expected to be a strong translation inhibitor. In vitro and bicistronic strategies were used to show that the VEGF mRNA translation was cap independent and occurred by an internal ribosome entry process. For the first time, we demonstrate that two independent internal ribosome entry sites (IRESs) are present in this 5′ UTR. IRES A is located within the 300 nucleotides upstream from the AUG start codon. RNA secondary structure prediction and site-directed mutagenesis allowed the identification of a 49-nucleotide structural domain (D4) essential to IRES A activity. UV cross-linking experiments revealed that IRES A activity was correlated with binding of a 100-kDa protein to the D4 domain. IRES B is located in the first half of the 5′ UTR. An element between nucleotides 379 and 483 is required for its activity. Immunoprecipitation experiments demonstrated that a main IRES B-bound protein was the polypyrimidine tract binding protein (PTB), a well-known regulator of picornavirus IRESs. However, we showed that binding of the PTB on IRES B does not seem to be correlated with its activity. Evidence is provided of an original cumulative effect of two IRESs, probably controlled by different factors, to promote an efficient initiation of translation at the same AUG codon.

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Sasaki, Jun, and Nobuhiko Nakashima. "Translation Initiation at the CUU Codon Is Mediated by the Internal Ribosome Entry Site of an Insect Picorna-Like Virus In Vitro." Journal of Virology 73, no. 2 (February 1, 1999): 1219–26. http://dx.doi.org/10.1128/jvi.73.2.1219-1226.1999.

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ABSTRACT AUG-unrelated translation initiation was found in an insect picorna-like virus, Plautia stali intestine virus (PSIV). The positive-strand RNA genome of the virus contains two nonoverlapping open reading frames (ORFs). The capsid protein gene is located in the 3′-proximal ORF and lacks an AUG initiation codon. We examined the translation mechanism and the initiation codon of the capsid protein gene by using various dicistronic and monocistronic RNAs in vitro. The capsid protein gene was translated cap independently in the presence of the upstream cistron, indicating that the gene is translated by internal ribosome entry. Deletion analysis showed that the internal ribosome entry site (IRES) consisted of approximately 250 bases and that its 3′ boundary extended slightly into the capsid-coding region. The initiation codon for the IRES-mediated translation was identified as the CUU codon, which is located just upstream of the 5′ terminus of the capsid-coding region by site-directed mutagenesis. In vitro translation assays of monocistronic RNAs lacking the 5′ part of the IRES showed that this CUU codon was not recognized by scanning ribosomes. This suggests that the PSIV IRES can effectively direct translation initiation without stable codon-anticodon pairing between the initiation codon and the initiator methionyl-tRNA.

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Journal articles on the topic 'Iris scanning'

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