52 results on '"Concentric ring"'
Search Results
2. Cover Picture: A Concentric Ring Electrode for a Wall‐jet Cell in a Microfluidic Device (Electroanalysis 9/2019)
- Author
-
Koki Hoshikawa, Keine Nishiyama, Akihiko Ishida, Manabu Tokeshi, Hirofumi Tani, and Masatoshi Maeki
- Subjects
Jet (fluid) ,Optics ,Materials science ,business.industry ,Electrode ,Microfluidics ,Electrochemistry ,Cover (algebra) ,business ,Concentric ring ,Analytical Chemistry - Published
- 2019
- Full Text
- View/download PDF
Catalog
3. Solution‐Processed Large‐Scale Concentric‐Ring Laser on Two‐Dimensional Ruddlesden–Popper Perovskites Thin Films
- Author
-
Qing Liao, Bingqian Zhang, Hongbing Fu, Peng Liu, Chunling Gu, and Guifen Tian
- Subjects
Materials science ,Scale (ratio) ,business.industry ,Laser array ,Laser ,Atomic and Molecular Physics, and Optics ,Concentric ring ,Electronic, Optical and Magnetic Materials ,Solution processed ,law.invention ,law ,Optoelectronics ,Thin film ,business - Published
- 2021
- Full Text
- View/download PDF
4. Coordinated disassembly of the divisome complex inEscherichia coli
- Author
-
Gunnar von Heijne, Stephen Toddo, Kiavash Mirzadeh, Bill Söderström, Ulf Skoglund, and Daniel O. Daley
- Subjects
0301 basic medicine ,Cell division ,030106 microbiology ,Sequence (biology) ,Divisome complex ,Biology ,Bioinformatics ,medicine.disease_cause ,Microbiology ,Concentric ring ,03 medical and health sciences ,030104 developmental biology ,medicine ,biology.protein ,Biophysics ,FtsA ,FtsZ ,Molecular Biology ,Escherichia coli ,Biological sciences - Abstract
The divisome is the macromolecular complex that carries out cell division in Escherichia coli. Every generation it must be assembled, and then disassembled so that the sequestered proteins can be recycled. Whilst the assembly process has been well studied, virtually nothing is known about the disassembly process. In this study, we have used super-resolution SIM imaging to monitor pairs of fluorescently tagged divisome proteins as they depart from the division septum. These simple binary comparisons indicated that disassembly occurs in a coordinated process that consists of at least five steps: [FtsZ, ZapA] ⇒ [ZipA, FtsA] ⇒ [FtsL, FtsQ] ⇒ [FtsI, FtsN] ⇒ [FtsN]. This sequence of events is remarkably similar to the assembly process, indicating that disassembly follows a first-in, first-out principle. A secondary observation from these binary comparisons was that FtsZ and FtsN formed division rings that were spatially separated throughout the division process. Thus the data indicate that the divisome structure can be visualized as two concentric rings; a proto-ring containing FtsZ and an FtsN-ring. more...
- Published
- 2016
- Full Text
- View/download PDF
5. Epidermoid cyst of the testis: An atypical sonographic appearance
- Author
-
Hsin-Kai Wang, Shu-Ting Chen, Jane Wang, Shu-Huei Shen, Yung-Hui Lin, Yi-Chen Lai, Chui-Mei Tiu, Chin-Chen Pan, Cheng-Yen Chang, Hong-Jen Chiou, and Yi-Hong Chou
- Subjects
Pathology ,medicine.medical_specialty ,Epidermal Cyst ,business.industry ,Ultrasound ,Epidermoid cyst ,Anatomy ,medicine.disease ,Concentric ring ,030218 nuclear medicine & medical imaging ,Benign tumor ,03 medical and health sciences ,0302 clinical medicine ,030220 oncology & carcinogenesis ,otorhinolaryngologic diseases ,Testicular Epidermoid Cyst ,Medicine ,Radiology, Nuclear Medicine and imaging ,Ultrasonography ,Differential diagnosis ,business - Abstract
Epidermoid cysts are rare. They represent the most common benign tumor of the testis. The sonographic appearances of testicular epidermoid cysts usually include avascular, mostly lamellated, heterogeneous internal echotexture, with hypoechoic and hyperechoic concentric rings, accounting for the typical onion-ring appearance. On MRI, epidermoid cysts show a low-signal-intensity center, with internal concentric rings of alternating high- and low-signal intensity on T2-weighted images, which correlates with the onion-ring appearance. We report a patient with testicular epidermoid cyst with atypical ultrasound and MRI appearances that led to the erroneous initial diagnosis of "burned-out" tumor. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:448-451, 2016. more...
- Published
- 2016
- Full Text
- View/download PDF
6. Coil compression in simultaneous multislice functional MRI with concentric ring slice-GRAPPA and SENSE
- Author
-
Alan Chu and Douglas C. Noll
- Subjects
medicine.diagnostic_test ,Computer science ,business.industry ,Simultaneous multislice ,Compression method ,computer.software_genre ,Concentric ring ,030218 nuclear medicine & medical imaging ,03 medical and health sciences ,0302 clinical medicine ,Kernel (image processing) ,Electromagnetic coil ,medicine ,Radiology, Nuclear Medicine and imaging ,Computer vision ,Data mining ,Artificial intelligence ,Functional magnetic resonance imaging ,business ,computer ,030217 neurology & neurosurgery - Abstract
Purpose Simultaneous multislice (SMS) imaging is a useful way to accelerate functional magnetic resonance imaging (fMRI). As acceleration becomes more aggressive, an increasingly larger number of receive coils are required to separate the slices, which significantly increases the computational burden. We propose a coil compression method that works with concentric ring non-Cartesian SMS imaging and should work with Cartesian SMS as well. We evaluate the method on fMRI scans of several subjects and compare it to standard coil compression methods. Methods The proposed method uses a slice-separation k-space kernel to simultaneously compress coil data into a set of virtual coils. Five subjects were scanned using both non-SMS fMRI and SMS fMRI with three simultaneous slices. The SMS fMRI scans were processed using the proposed method, along with other conventional methods. Code is available at https://github.com/alcu/sms. Results The proposed method maintained functional activation with a fewer number of virtual coils than standard SMS coil compression methods. Compression of non-SMS fMRI maintained activation with a slightly lower number of virtual coils than the proposed method, but does not have the acceleration advantages of SMS fMRI. Conclusion The proposed method is a practical way to compress and reconstruct concentric ring SMS data and improves the preservation of functional activation over standard coil compression methods in fMRI. Magn Reson Med, 2015. © 2015 Wiley Periodicals, Inc. more...
- Published
- 2015
- Full Text
- View/download PDF
7. A new Eocene fossil of the genus Phycopeltis (Ulvophyceae, Chlorophyta)
- Author
-
Fabio Rindi, Jennifer M. Bannister, Daphne E. Lee, and Phil M. Novis
- Subjects
Trentepohliales ,biology ,Gametangium ,Ulvophyceae ,Molecular evidence ,Plant Science ,Chlorophyta ,Aquatic Science ,biology.organism_classification ,Concentric ring ,Phycopeltis ,Paleontology ,Genus ,Botany - Abstract
A fossil of the aerophytic green algal genus Phycopeltis (Trentepohliaes, Ulvophyceae) dated to 35 Ma, is reported from the Pikopiko Fossil Forest, Southland, New Zealand. Previous reports of fossilized Phycopeltis have been subsequently synonymized with fungi by other authors; however, our specimen is not vulnerable to their criticisms. Inflated cells present in two approximately concentric rings are interpreted as gametangia, with irregular structures resembling the gametangial pores of modern material; sporophytic material is absent. The fossil resembles the modern disc-forming species P. novae-zelandiae, P. expansa, and P. arundinacea. The limited material available prevents the assignation of a specific epithet, but the habit and dimensions of the fossil clearly fall within those of modern representatives of the genus. Its single cell thickness throughout, absence of distinct melanization, and larger size demonstrate that it is not a fungal shield. The specimen constitutes arguably the most convincing fossil belonging to Trentepohliales, and the first unambiguously for the genus Phycopeltis. It is consistent in age with other known fossils of the order that, when combined with molecular evidence, suggests a terrestrial radiation far more recent than that of land plants. more...
- Published
- 2015
- Full Text
- View/download PDF
8. Formation Age and Evolution Time Span of the Koktokay No. 3 Pegmatite, Altai, NW China: Evidence from U-Pb Zircon and40Ar-39Ar Muscovite Ages
- Author
-
Qifeng Zhou, Kezhang Qin, MingJian Cao, Dongmei Tang, Ye Tian, and Chunlong Wang
- Subjects
Dike ,geography ,geography.geographical_feature_category ,Muscovite ,Geochemistry ,Geology ,engineering.material ,Concentric ring ,Hydrothermal circulation ,Geochemistry and Petrology ,engineering ,Pegmatite ,Zircon - Abstract
The Koktokay No. 3 pegmatite is the largest Li–Be–Nb–Ta–Cs pegmatitic rare-metal deposit of the Chinese Altai orogenic belt, and is famous for its concentric ring zonation pattern (nine internal zones). However, the formation age and evolution time span have been controversial. Here, we present the results of LA-ICP–MS zircon U–Pb dating and muscovite 40Ar–39Ar dating. Four groups of zircon U–Pb ages (∼210 Ma, ∼193–198 Ma, ∼186–187 Ma and ∼172 Ma) for Zones II, V, VI, VII, and VIII, and a weighed mean 206Pb/238U age of 965 ± 11 Ma for Zone IV are identified. Also, Zones II, IV, and VI have muscovite 40Ar–39Ar plateau ages of 179.7 ± 1.1 Ma, 182.1 ± 1.0 Ma, and 181.8 ± 1.1 Ma, respectively. Considering previous U–Pb age studies (Zones I, V, and VII), the ages of emplacement, Li mineralization peak, hydrothermal stage of the No. 3 pegmatite are in ranges of 193–198 Ma, 184–187 Ma and 172–175 Ma, with weighted mean 206Pb–238U ages of 194.8 ± 2.3 Ma, 186.6 ± 1.3 Ma and 173.1 ± 3.9 Ma, respectively. The No. 3 pegmatite formed in the early Jurassic. The results of xenocrysts suggest that there is another pegmatite forming event of around 210 Ma in the mining district and the old zircon U–Pb ages imply that Neoproterozoic crustal rocks pertain to sources of the No. 3 pegmatite. Including the previous muscovite 40Ar–39Ar age studies (Zones I and V), a cooling age range of 177–182 Ma is considered as the time of hydrothermal stage and end of formation. The evolution process of the No. 3 pegmatite lasted 16 Ma. Therein, the magmatic stage continued for 9–11 Myr and the magmatic–hydrothermal transition and hydrothermal stages were sustained at 5–7 Ma. These time spans are long because of huge scale, cupola shape, large formation depth, and complex internal zoning patterns and formation processes. Considering some pegmatite dikes in the Chinese Altai, there is an early Jurassic pegmatite forming event. more...
- Published
- 2015
- Full Text
- View/download PDF
9. Synthesis of thinned concentric ring array antenna in predefined phi-planes using binary firefly and binary particle swarm optimization algorithm
- Author
-
Ananya Mahanti, Gautam Kumar Mahanti, and Anirban Chatterjee
- Subjects
Beamwidth ,Planar ,Null (radio) ,Modeling and Simulation ,Binary number ,Firefly algorithm ,Electrical and Electronic Engineering ,Antenna (radio) ,Algorithm ,Concentric ring ,Computer Science Applications ,Mathematics ,Power (physics) - Abstract
A binary firefly algorithm inspired by the behavior of artificial fireflies has been applied to thin a planar concentric ring array antenna to minimize the peak sidelobe level in a number of predefined i¾?-planes. Two different cases comprising two different design specifications for the optimized thinned array have been considered. In the first case, the array is thinned to reduce the peak sidelobe level while keeping the first null beamwidth and half power beamwidth of the array below their specified values in all the defined i¾?-planes. In the second case, peak sidelobe level of the array is reduced regardless of any pre-specified values of first null beamwidth and half power beamwidth. To illustrate the superiority of binary firefly algorithm, the thinning of the array for the two different cases has been compared with binary particle swarm optimization algorithm. Results clearly show the superiority of binary firefly algorithm in finding optimum solutions for both cases. Copyright © 2014 John Wiley & Sons, Ltd. more...
- Published
- 2014
- Full Text
- View/download PDF
10. Geometry-Induced Mechanical Properties of Carbon Nanotube Foams
- Author
-
Chiara Daraio, Ludovica Lattanzi, Jordan R. Raney, and Luigi De Nardo
- Subjects
Effective density ,Materials science ,Geometry ,Carbon nanotube ,Condensed Matter Physics ,Concentric ring ,law.invention ,Stress (mechanics) ,Compressive deformation ,Template ,Energy absorption ,law ,General Materials Science ,Composite material - Abstract
Carbon nanotube (CNT) foams have unmatched energy absorption properties derived from their complex hierarchical structure. The control of the micro-scale geometry of these foams allows tuning their behavior to specific application-driven needs. Geometrical structures in CNT foams are obtained by synthesizing CNTs on substrates patterned with different growth templates: circles, lines and concentric rings. To study the effects of the microstructural geometry on the bulk mechanical response of the foams, the samples are tested under cyclic quasi-static compressive deformation (up to 50% strain). The geometry of the patterns plays a fundamental role on the samples' macroscopic energy absorption capability, maximum stress, and strain recovery. Patterned CNT structures demonstrated mechanical properties comparable or improved over non-patterned, bulk CNT foams, but with much lower density. Quasi-static compressive tests performed on different patterned structures with the same effective density (ρ = 0.02 g cm^(−3)) exhibit considerably different responses. For example, the stress reached by foams patterned in concentric rings is ≈15 times higher than that observed for pillars and lines. The results show how the mechanical response of CNT foams can be tailored by varying the CNT microstructural architecture. more...
- Published
- 2014
- Full Text
- View/download PDF
11. Characterization of the thickness of different corneal zones in glaucoma: effect on dynamic contour, Goldmann and rebound tonometries
- Author
-
Laura Morales-Fernandez, Julian Garcia-Feijoo, Enrique Santos-Bueso, Federico Saenz-Frances, Jose M. Martinez-de-la-Casa, Luis Jañez, Lara Borrego-Sanz, and Julián García-Sánchez
- Subjects
medicine.medical_specialty ,Corneal Pachymetry ,genetic structures ,Gonioscopy ,Glaucoma ,Sensitivity and Specificity ,Goldmann applanation tonometry ,Concentric ring ,Mean difference ,Cornea ,Tonometry, Ocular ,Ophthalmology ,Linear regression ,medicine ,Humans ,Intraocular Pressure ,Mathematics ,Organ Size ,General Medicine ,REBOUND TONOMETRY ,medicine.disease ,Healthy Volunteers ,eye diseases ,Cross-Sectional Studies ,medicine.anatomical_structure ,Area Under Curve ,Optometry ,sense organs ,Glaucoma, Open-Angle - Abstract
Purpose: To characterize five models of corneal thickness circular zoning in a sample of healthy controls and a sample of patients with primary open-angle glaucoma (POAG) and to determine their effect on Goldmann (GAT), dynamic contour (DCT) and rebound tonometers (RT). Methods: The study participants were 122 controls and 129 cases. Five corneal thickness zoning models (A, B, C, D and E) were constructed. The partitioning pattern consisted of a circle centred at the corneal apex and several concentric rings, until the limbus; the contours of each ring followed the geometry of the corneal contour of each participant. In Model A, the central circle was 1 mm in diameter and five concentric rings were established. Mean was obtained for each zone for both samples and compared between them using a t-test. The effect on the tonometers of central cornel thickness (CCT) and mean thickness of the zones generated was determined through several linear regression models (one per tonometer and per sample). Results: According to a t-test, cases and controls differ in zones I [mean difference (MD): 17.93 μm], V (MD: 25.52 μm) and VI (MD: 31.78 μm) of model A (higher values in the cases sample). RT was affected by CCT (controls: B = 0.089; cases: B = 0.081). DCT was affected by zone IV of model A (controls: B = −0.029; cases: B = −0.012). GAT was affected by CCT (controls: B = 0.043; cases: B = 0.025) and zone III of model A (controls: B = −0.045; cases: B = −0.033). Conclusion: Our results highlight the importance of the thickness of other regions of the cornea different from its main centre in discriminating between healthy controls and patients with POAG and in IOP measurements made using DCT, GAT and RT. more...
- Published
- 2013
- Full Text
- View/download PDF
12. Patterns of Population Growth in Peri-Urban Accra, Ghana
- Author
-
Charles Yaw Oduro and Petra L. Doan
- Subjects
Urban form ,Sociology and Political Science ,Developing country ,Development ,Census ,Port (computer networking) ,Concentric ring ,Urban expansion ,Urban Studies ,Geography ,Urbanization ,Population growth ,Economic geography ,Demography - Abstract
Urbanization in Africa (and the wider developing world for that matter) has often been misunderstood by Western observers on the lookout for Western-style cities and suburbs. In these parts of the world, rapid urbanization has led to continuing changes in the form and shape of cities, as peri-urban zones shift swiftly from rural to urban. While some descriptions of the peri-urban zone suggest an amorphous area filled with low-income residents, others argue that the zone is highly diverse. Using population census data, spatial modeling and regression analysis, we show that urban expansion at the edge of the city of Accra, Ghana, is not amorphous and does indeed show some discernible patterns. These patterns are represented by four hypotheses tested in this study - the spreading pancake, development node, village magnet and ribbon hypotheses. While the assumption that urban growth occurs in concentric rings around a central city (represented by the spreading pancake model) holds for Accra, this pattern of growth combines with other patterns to create a still-evolving urban form in the city's peri-urban zone. These include clustering of growth around a port city, a number of old villages and along improved highways radiating from the city. more...
- Published
- 2011
- Full Text
- View/download PDF
13. Concentric Ring Pattern Formation in a Competing Crystallization and Phase Separation Process
- Author
-
Yongri Liang, Fenghua Chen, Charles C. Han, Xu-Ming Xie, Weichao Shi, and He Cheng
- Subjects
Materials science ,Polymers and Plastics ,Phase separation process ,Organic Chemistry ,Pattern formation ,Concentric ,Ring (chemistry) ,Radial direction ,Phase Transition ,Concentric ring ,Polyethylene Glycols ,law.invention ,Crystallography ,law ,Chemical physics ,Materials Chemistry ,Polymethyl Methacrylate ,Polymer blend ,Crystallization - Abstract
Spherulitic patterns usually form in the single process of crystallization in polymer blends. But when phase separation intervenes under deep quench, the radial growth of the initial spherulitic patterns tends to invert into concentric alternating crystalline-/amorphous-rich ring structures. Within crystalline-rich regions, lateral lamellae orient in the tangential direction rather than in the usual radial direction. We demonstrate the determining factor for this first observed phenomenon is the concentration deviation enhanced phase separation dynamics at the growth interface of crystals. more...
- Published
- 2011
- Full Text
- View/download PDF
14. Fat/water separation using a concentric rings trajectory
- Author
-
Dwight G. Nishimura, Hochong H. Wu, and Jin Hyung Lee
- Subjects
Field (physics) ,Computer science ,business.industry ,Separation (aeronautics) ,Sample (graphics) ,Signal ,Concentric ring ,law.invention ,Optics ,law ,Trajectory ,Radiology, Nuclear Medicine and imaging ,Cartesian coordinate system ,business ,Image resolution ,Algorithm - Abstract
The concentric rings two-dimensional (2D) k-space trajectory enables flexible trade-offs between image contrast, signal-to-noise ratio (SNR), spatial resolution, and scan time. However, to realize these benefits for in vivo imaging applications, a robust method is desired to deal with fat signal in the acquired data. Multipoint Dixon techniques have been shown to achieve uniform fat suppression with high SNR-efficiency for Cartesian imaging, but application of these methods for non-Cartesian imaging is complicated by the fact that fat off-resonance creates significant blurring artifacts in the reconstruction. In this work, two fat–water separation algorithms are developed for the concentric rings. A retracing design is used to sample rings near the center of k-space through multiple revolutions to characterize the fat–water phase evolution difference at multiple time points. This acquisition design is first used for multipoint Dixon reconstruction, and then extended to a spectroscopic approach to account for the trajectory's full evolution through 3D k-t space. As the trajectory is resolved in time, off-resonance effects cause shifts in frequency instead of spatial blurring in 2D k-space. The spectral information can be used to assess field variation and perform robust fat–water separation. In vivo experimental results demonstrate the effectiveness of both algorithms. Magn Reson Med, 2009. © 2008 Wiley-Liss, Inc. more...
- Published
- 2008
- Full Text
- View/download PDF
15. Anomalous secondary structures in stem and root of two typical halophytes
- Author
-
Lingan Kong and Fazeng Li
- Subjects
biology ,Scape ,fungi ,Plant Science ,biology.organism_classification ,Plumbaginaceae ,Concentric ring ,Halophyte ,Botany ,Phloem ,Limonium sinense ,Chenopodiaceae ,Ecology, Evolution, Behavior and Systematics ,Vascular tissue - Abstract
Limonium sinense (Girard) O. Kuntze (Plumbaginaceae) and Suaeda salsa (L.) Pal. (Chenopodiaceae), both typical halophytes, have been used to investigate the peculiar structural features adapted to saline conditions, with a special emphasis on the anomalous secondary structure of stem and root. The results showed that in saline environments, L. sinense developed tripartite vascular cylinders in the root and cortical bundles in the scape. Suaeda salsa developed concentric rings of vascular tissue and interxylary phloem in the root and stem. Based on these findings, we discuss the adaptive significance of these anomalous secondary structures for plants living in saline environments. more...
- Published
- 2008
- Full Text
- View/download PDF
16. Directed Self-Assembly of Gradient Concentric Carbon Nanotube Rings
- Author
-
Michael R. Kessler, Hyunhyub Ko, Wonje Jeong, Vladimir V. Tsukruk, Suck Won Hong, and Zhiqun Lin
- Subjects
chemistry.chemical_classification ,Directed self assembly ,Materials science ,Contact line ,Substrate (electronics) ,Polymer ,Carbon nanotube ,Conjugated system ,Concentric ,Condensed Matter Physics ,Concentric ring ,Electronic, Optical and Magnetic Materials ,law.invention ,Biomaterials ,chemistry ,law ,Electrochemistry ,Composite material - Abstract
Hundreds of gradient concentric rings of linear conjugated polymer, (poly[2-methoxy-5-(2-ethylhexyloxy)-1,4- phenylenevinyl-ene], i.e., MEH-PPV) with remarkable regularity over large areas were produced by controlled "stick-slip" motions of the contact line in a confined geometry consisting of a sphere on a flat substrate (i.e., sphere-on-flat geometry). Subsequently, MEH-PPV rings were exploited as a template to direct the formation of gradient concentric rings of multiwalled carbon nanotubes (MWNTs) with controlled density. This method is simple, cost effective, and robust, combining two consecutive self-assembly processes, namely, evaporation-induced self-assembly of polymers in a sphere-on-flat geometry, followed by subsequent directed self-assembly of MWNTs on the polymer-templated surfaces. more...
- Published
- 2008
- Full Text
- View/download PDF
17. Identification of diabetic macular oedema using retinal thickness measurements
- Author
-
Lars Loumann Knudsen
- Subjects
Adult ,medicine.medical_specialty ,genetic structures ,Macular oedema ,Diagnostic Techniques, Ophthalmological ,Sensitivity and Specificity ,Macular Edema ,Retina ,Concentric ring ,Foveola ,chemistry.chemical_compound ,Ophthalmology ,Humans ,Medicine ,Aged ,Aged, 80 and over ,Diabetic Retinopathy ,Laser Coagulation ,Anthropometry ,business.industry ,Retinal ,Middle Aged ,Diabetic maculopathy ,eye diseases ,chemistry ,Diabetic macular oedema ,Optometry ,sense organs ,business - Abstract
Background: Identification of clinically significant macular oedema (CSMO) involves human depth perception, which is subject to a degree of uncertainty. However, although the ability to obtain objective thickness measurements of the central macular region may be advantageous, the topography of the macular region suggests that average thickness measurements represent a simplification of the topographic profile of the region. This study explored the applicability of additional sub-analysis of central macular thickness measurements. Methods: The study included 47 eyes of 47 normal subjects and 158 ocular examinations of 38 eyes from 22 diabetic subjects with and without CSMO. All eyes underwent central macular thickness measurements using retinal thickness analysis equipment. Eyes of diabetes subjects were classified as being without CSMO (n = 53), with focal CSMO (n = 50) and with diffuse CSMO (n = 55). The central macular region was subdivided into narrow concentric rings around the foveola, using a new invention, and the thicknesses of the individual concentric rings were calculated. The sensitivity and specificity of the CSMO diagnosis were established using the average thickness and the thicknesses of the concentric rings. Results: The average thickness of the central macular region was found to be 165.1 µm in eyes of normal subjects and 192.3 µm in eyes without CSMO. It increased non-significantly to 198.2 µm in eyes with focal CSMO and significantly to 236.9 µm in eyes with diffuse CSMO. Sensitivity for focal CSMO was 48.0% with average thickness measurements and 83.6% with concentric rings. Corresponding values for detection of diffuse CSMO were 91.7% and 96.1%, respectively. Specificity was 77.4% with average thickness measurements and 79.7% with concentric rings. Conclusions: Thickness measurements of the central macular region can be used to distinguish between eyes with and without diffuse CSMO, but not between eyes with and without focal CSMO. Additional sub-analysis based on concentric rings around the foveola seems to be a useful clinical tool that increases diagnostic certainty in these eyes. more...
- Published
- 2006
- Full Text
- View/download PDF
18. Raman spectroscopic study of the heterogeneity of microcolonies of a pigmented bacterium
- Author
-
James R. Goodwin, Peter M. Fredericks, and Louise M. Hafner
- Subjects
biology ,Chemistry ,Analytical chemistry ,Cell concentration ,biology.organism_classification ,Halophile ,Concentric ring ,Raman microspectroscopy ,symbols.namesake ,Pigment ,visual_art ,symbols ,visual_art.visual_art_medium ,General Materials Science ,Halobacterium salinarium ,Raman spectroscopy ,Spectroscopy ,Bacteria - Abstract
Small colonies (90 – 350 μm in diameter) of the pigmented halophilic bacterium Halobacterium salinarium have been studied by Raman microspectroscopy using excitation at 632.8 nm. The Raman spectra were dominated by bands due to carotene compounds. The intensity of the pigment bands varied across the diameter of the colonies in a way that suggested the presence of concentric rings of higher pigment concentration. Although the colonies were grown in a transparent incubator in an open laboratory, it was demonstrated that the rings were not a result of the diurnal variation of light and dark. These results support a proposed model relating cell motility and cell concentration. more...
- Published
- 2006
- Full Text
- View/download PDF
19. Trichophyton Tonsurans Infection Manifesting as Multiple Concentric Annular Erythemas
- Author
-
Tomoko Otuka, Takeshi Ouchi, Keisuke Nagao, Toyoko Inazumi, and Yasuki Hata
- Subjects
Adult ,Male ,medicine.medical_specialty ,biology ,Trichophyton concentricum ,business.industry ,Dermatology ,General Medicine ,biology.organism_classification ,medicine.disease ,Concentric ring ,Tinea ,Erythema ,medicine ,Humans ,Tinea imbricata ,business ,Trichophyton tonsurans - Abstract
We report a case of dermatophytosis in a Judo wrestler caused by Trichophyton tonsurans (T. tonsurans) with clinical features that mimicked the concentric rings of tinea imbricata. Tinea imbricata is a unique dermatophytosis caused by Trichophyton concentricum (T. concentricum), observed endemically in subtropical to torrid zones and characterized by impressive concentric rings. We found three similar cases of the dermatophytosis in the literature that were reported as tinea pseudoimbricata or tinea indecisiva. All of these cases were associated with systemic or local immunosuppression, perhaps simulating the mechanism of tinea imbricata, which is known to involve the lack of delayed type hypersensitivity to T. concentricum. These cases imply that iatrogenic immunosuppression may perhaps play an important role in the development of the unique clinical features mimicking tinea imbricata. Furthermore, three of the four cases, including the presented case, were caused by T. tonsurans. It may be necessary to consider T. tonsurans infection when multiple concentric erythemas are encountered. more...
- Published
- 2005
- Full Text
- View/download PDF
20. Microstructure and innervation of the mystacial vibrissal follicle-sinus complex in bearded seals,Erignathus barbatus (Pinnipedia: Phocidae)
- Author
-
Christopher D. Marshall, Christian Lydersen, Kit M. Kovacs, and Heidi Amin
- Subjects
integumentary system ,biology ,Seals, Earless ,Sensory system ,Feeding Behavior ,Anatomy ,biology.organism_classification ,Agricultural and Biological Sciences (miscellaneous) ,Concentric ring ,Follicle ,medicine.anatomical_structure ,nervous system ,Vibrissae ,Erignathus barbatus ,medicine ,Animals ,Thermal protection ,Integument ,Hair Follicle ,Mechanoreceptors ,Sinus (anatomy) - Abstract
Vibrissal follicle-sinus complexes (F-SCs) are sensory receptors of the mammalian integument system. They are best developed within Pinnipedia. The objective of this study was to investigate the F-SCs of bearded seals (Erignathus barbatus) for benthic foraging adaptations. Bearded seals possessed approximately 244 mystacial F-SCs. In this species, F-SCs consisted of an outer dermal capsule (DC) surrounding a blood sinus system [upper cavernous sinus (UCS), ring sinus (RS), and lower cavernous sinus (LCS)] and concentric rings of epidermal tissue. The UCS comprised up to 62% of the F-SC length and may function as thermal protection for mechanoreceptors. A large asymmetrical ringwulst was located in the RS. A deep vibrissal nerve penetrated the DC at its base and terminated on mechanoreceptors in the epidermal tissues of the LCS and RS. The mean number of myelinated axons per F-SC was 1,314 (range, 811–1,650) and was among the highest number of axons per F-SC reported to date. An estimated mean number of 320,616 myelinated axons innervate the entire mystacial vibrissal array. Merkel-Neurite complexes (MNCs) and small simple laminated corpuscles were found in the region of the LCS. Myelinated axons also terminated on MNCs and lanceolate endings apical to the ringwulst. The number of F-SCs, their geometry in the mystacial region, the number of myelinated axons per F-SC, and the distribution of mechanoreceptors support the premise that pinniped vibrissae are sensitive active-touch receptor systems, and that structural differences in bearded seals, relative to other phocids, may be adaptations for benthic foraging. © 2005 Wiley-Liss, Inc. more...
- Published
- 2005
- Full Text
- View/download PDF
21. Concentric rings as frequency-selective surfaces on isotropic chiral slabs
- Author
-
S. Uckun and T. Ege
- Subjects
Materials science ,business.industry ,Isotropy ,Concentric ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Concentric ring ,Selective surface ,Electronic, Optical and Magnetic Materials ,Transmission properties ,Reflection (mathematics) ,Optics ,Slab ,Electrical and Electronic Engineering ,business ,Microwave - Abstract
Periodic structures or frequency-selective surfaces (FSSs), such as arrays of rings printed on a dielectric substrate, have reflection and transmission properties which change with frequency. In this study, the arrays of two concentric conducting rings printed on an isotropic chiral slab are investigated and their transmission/reflection characteristics are presented. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 79–83, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21267 more...
- Published
- 2005
- Full Text
- View/download PDF
22. Macroscopic observation of healing process in stress-whitened polypropylene under hydrostatic pressure
- Author
-
Jong Keun Lee, Jong Hyun Kim, K. D. Pae, and H.-C. Chu
- Subjects
Polypropylene ,Materials science ,Polymers and Plastics ,Atmospheric pressure ,Hydrostatic pressure ,Macroscopic observation ,General Chemistry ,Concentric ring ,law.invention ,chemistry.chemical_compound ,Optical microscope ,chemistry ,law ,Ultimate tensile strength ,Materials Chemistry ,Composite material - Abstract
Stress-whitening and its healing phenomena in polypropylene under tensile load superposed on hydrostatic pressure up to 89.7 MPa have been investigated. Tensile samples of polypropylene were first cold-drawn beyond the yielding at atmospheric pressure to develop stress-whitening, and the stress-whitened samples were further drawn under various intensities of hydrostatic pressure (P = 7.6 - 89.7 MPa). As a result of the experiment, morphological changes in stress-whitening occurred in the necked gauge sections (R I and R II ) and in the shoulders of the neck (R III ). The macroscopic observations were made by optical microscopy on the entire specimen and on the sliced sections. The stress-whitening in the R I region was found to be either partially or nearly completely healed depending on the level of hydrostatic pressure at which the specimens were drawn. The cross sections of polypropylene specimens exhibited two concentric ring structures upon stress-whitening. The stress-whitened core region is surrounded by clear shell region. The size and degree of healing of stress-whitening in the core region were affected by the applied hydrostatic pressure. more...
- Published
- 2002
- Full Text
- View/download PDF
23. A Comparison of Calcified Structures for Aging Bluefish in the Chesapeake Bay Region
- Author
-
Ann M. Sipe and Mark E. Chittenden
- Subjects
body regions ,Dorsum ,medicine.anatomical_structure ,Chesapeake bay ,medicine ,Pomatomidae ,sense organs ,Anatomy ,Aquatic Science ,Ecology, Evolution, Behavior and Systematics ,Concentric ring ,Geology ,Otolith - Abstract
We compared whole and sectioned otoliths, scales, dorsal spine sections, opercular bones, and vertebrae for aging bluefish Pomatomus saltatrix from the Chesapeake Bay region. Opercular bones and vertebrae were unusable; they were spongy and pitted, and contained no visible marks. The remaining structures exhibited concentric rings that were interpreted as annual marks; however, structures differed greatly in mark clarity. Over the age range 1-14 years, sectioned otoliths were the best structure, consistently showing the clearest marks, highest confidence scores, and highest within- and between-reader agreement. Whole otoliths were the second best structure, providing the second highest overall within-reader agreement and 95% agreement with sectioned otoliths to age 4. Scales were inferior to sectioned and whole otoliths, especially after age 4, when within-reader agreement was only 33% and agreement with sectioned otoliths was only 26%. Dorsal spine sections were undesirable for aging bluefish, p... more...
- Published
- 2002
- Full Text
- View/download PDF
24. Few and Far Between? An Environmental Equity Analysis of the Geographic Distribution of Hazardous Waste Generation
- Author
-
Mark Atlas
- Subjects
Low income ,Geographic distribution ,Equity (economics) ,Environmental equity ,Minority group ,Hazardous waste ,Environmental protection ,General Social Sciences ,Business ,Concentric ring - Abstract
Objective. This article examines whether the generation of hazardous waste is concentrated in communities that are disproportionately minority or low income. Whereas much environmental equity research has focused on commercial facilities managing hazardous waste, facilities that generate and manage their own wastes—which account for over 98 percent of hazardous waste volume—have been ignored. Methods. The demographic characteristics were determined of people in geographic concentric rings around hazardous waste generators accounting for most of the country's 1997 hazardous waste volume. Results. My analyses indicate no tendency for disproportionately minority communities to be near these facilities. In fact, relatively few people are near where most hazardous waste is generated. Although a few of these facilities have large numbers of minority people around them, most are in areas with higher than average white populations. There was, however, a tendency for low-income communities to be near these facilities. Conclusions. To the extent that there are potential risks from the presence of hazardous waste at facilities, most of this risk is in relatively unpopulated areas. The presence of hazardous waste is not concentrated in areas that are disproportionately minority or low income. more...
- Published
- 2002
- Full Text
- View/download PDF
25. Serial magnetic resonance imaging in patients with Bal�'s concentric sclerosis: Natural history of lesion development
- Author
-
Nai Shin Chu, Chi Jen Chen, Chin Song Lu, and Chung Yang Sung
- Subjects
medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Follow up studies ,Magnetic resonance imaging ,Concentric ,Concentric ring ,Surgery ,Lesion ,Serial magnetic resonance imaging ,Nuclear magnetic resonance ,Neurology ,Medicine ,In patient ,Neurology (clinical) ,Concentric sclerosis ,medicine.symptom ,business - Abstract
We reviewed the magnetic resonance imaging scans from 22 serial studies of 5 patients with Balo's concentric sclerosis collected during the past 3 years. The data showed the concentric lesions did not occur simultaneously but developed step by step in a centrifugal direction. The development of lesions was preceded by an enhancing ring relatively devoid of demyelination and was followed by progressive demyelination occurring mainly at the inner aspect of the enhancement. The same process recurred on the edge of the previous enhanced zone. Thus, an appearance of concentric rings with alternating demyelinated and relatively myelin-preserved bands was formed. more...
- Published
- 1999
- Full Text
- View/download PDF
26. Balo’s concentric sclerosis: Value of magnetic resonance imaging in diagnosis
- Author
-
Mathew Alexander, A Kuruvilla, S Singh, and I P Korah
- Subjects
Adult ,Male ,Pathology ,medicine.medical_specialty ,Concentric ring ,Diagnosis, Differential ,White matter ,Cortex (anatomy) ,Biopsy ,medicine ,Humans ,Radiology, Nuclear Medicine and imaging ,Evoked potential ,Cerebral Cortex ,medicine.diagnostic_test ,business.industry ,Diffuse Cerebral Sclerosis of Schilder ,Magnetic resonance imaging ,Middle Aged ,Magnetic Resonance Imaging ,Frontal Lobe ,medicine.anatomical_structure ,Female ,Concentric sclerosis ,Tomography, X-Ray Computed ,business ,Mri findings - Abstract
We report two cases of Balo's concentric sclerosis that demonstrate the typical magnetic resonance imaging (MRI) findings of concentric rings of demyelination involving the superficial and deep white matter and sparing the cortex. In both cases biopsy was not performed as MRI findings and multi-mode evoked potential studies were consistent with demyelinating illness. The theories regarding the pathogenesis of this peculiar appearance are briefly reviewed. more...
- Published
- 1999
- Full Text
- View/download PDF
27. Epidermoid cyst of the testis
- Author
-
Li Cf, Wen-Sheng Tzeng, Chen Cy, and Mak Cw
- Subjects
Pathology ,medicine.medical_specialty ,genetic structures ,integumentary system ,Epidermal Cyst ,business.industry ,Testis sparing surgery ,Ultrasound ,Epidermoid cyst ,medicine.disease ,Concentric ring ,Biochemical tumour marker ,Vascular flow ,medicine ,Colour doppler ,Radiology, Nuclear Medicine and imaging ,business - Abstract
Epidermoid cysts, though having a variable sonographic appearance, may present with an onion peel configuration, that is, concentric rings of alternating hyperechogenicities and hypoechogenicities. The absence of vascular flow on colour Doppler sonography is also consistent with the avascular nature of these lesions. By combining these two sonographic features and the absence of biochemical tumour marker, preoperative diagnosis of epidermoid cyst is possible and may prompt a testis sparing surgery rather than orchidectomy. more...
- Published
- 2007
- Full Text
- View/download PDF
28. Ultrasonographic features of intestinal intussusception in 10 dogs
- Author
-
Panagiotis Mantis and Christopher R. Lamb
- Subjects
Male ,medicine.medical_specialty ,medicine.diagnostic_test ,business.industry ,Intestinal Neoplasm ,Ultrasound ,medicine.disease ,Concentric ring ,Surgery ,Dogs ,Intussusception (medical disorder) ,Abdominal ultrasonography ,Animals ,Medicine ,Female ,Intestinal intussusception ,Dog Diseases ,Radiology ,Ultrasonography ,Small Animals ,business ,Intussusception ,Pathological ,Retrospective Studies - Abstract
Records of dogs that had abdominal ultrasonography and surgical or pathological diagnosis of intestinal intussusception between February 1992 and June 1997 were reviewed retrospectively. Ultrasound images were reviewed with respect to appearance of the intussusception, suspected location, evidence of predisposing cause and concurrent lesions. Ten intussusceptions were found, affecting a variety of breeds. The mean (range) age of affected dogs was 2.5 (0.3 to seven) years (four females and six males) and the reported duration of clinical signs, 48 (one to 150) days. Intussusceptions were jejunojejunal (five dogs), ileocolic (three), caecocolic (one) and colocolic (one). A concentric ring sign was identified ultrasonographically in each dog and anatomical location predicted correctly in five instances. Additional ultrasonographic findings associated with intussusceptions included intestinal neoplasm in two dogs, enlarged abdominal lymph nodes in two, multiple mesenteric cysts in one and intestinal foreign body in a further dog. Thus, ultrasonography enables accurate diagnosis of intestinal intussusception and is a useful method for searching for concurrent or predisposing lesions. more...
- Published
- 1998
- Full Text
- View/download PDF
29. The life history of Ahnfeltiopsis paradoxa (Gigartinales, Rhodophyta) in laboratory culture
- Author
-
Tetsu Shimizu, Michio Masuda, and Kazuhiro Kogame
- Subjects
Ahnfeltiopsis paradoxa ,Botany ,Plant Science ,Phyllophoraceae ,Aquatic Science ,Biology ,Life history ,Gigartinales ,biology.organism_classification ,Agricultural and Biological Sciences (miscellaneous) ,Single filament ,Auxiliary cell ,Concentric ring - Abstract
SUMMARY The life history of the red alga Ahnfeltiopsis paradoxa (Suringar) Masuda (Phyllophoraceae, Gigartinales) from Japan was completed in laboratory culture. Carpospores isolated from field-collected plants germinated to form circular crusts that were composed of a monostromatic hypothallium consisting of radiating filaments, a polystromatic perithallium consisting of tightly coalescent erect filaments, and hypobasal tissue derived from the hypothallium. The crusts were induced to sporulate by transferring them from short-day to long-day regimes at 15° and 2°C. Each crust produced several nemathecia along 1-4 concentric rings. Intercalary, cruciately or decussately divided tetrasporangia were formed in 4-6 (1-2 at the margin of the nemathecium) successive cells of a single filament of the nemathecia. Tetraspore germlings gave rise to basal discs from which upright axes developed. The upright axes first grew without branches or were sparsely branched and later bore many marginal reproductive proliferations. Procarps and spermatangia were formed in the proliferations on different individuals. Carposporophytes developed on female plants that were co-cultured with male plants. Gonimoblast filaments were formed from an auxiliary cell that fused with a carpogonium. Carposporangia developed from gonimoblast filaments and medullary cells contacted by the gonimoblast filaments. Carpospores were discharged through carpostomes formed in the thickened cortex. Tetraspores were cultured from field-collected crusts of a morphology similar to that of cultured tetrasporophytes. They gave rise to upright gametophytic axes similar in morphology to this species as seen in the field. more...
- Published
- 1997
- Full Text
- View/download PDF
30. SU-F-T-35: Optimization of Bladder and Rectal Doses Using a Multi-Lumen Intracavitary Applicator for Gynecological Brachytherapy
- Author
-
S. Laoui, S Dietrich, V Sehgal, and Muthana Al-Ghazi
- Subjects
medicine.medical_specialty ,business.industry ,medicine.medical_treatment ,Radiation dose ,Brachytherapy ,Rectum ,General Medicine ,Concentric ring ,Surgery ,medicine.anatomical_structure ,Linear relationship ,Maximum dose ,medicine ,Dosimetry ,business ,Nuclear medicine ,Lumen (unit) - Abstract
Purpose: Radiation dose delivery for endometrial cancer using HDR techniques is limited by dose to bladder and rectum. A dosimetric study was performed using Varian Capri vaginal brachytherapy applicator to determine the optimal channel configuration which minimizes dose to bladder and rectum, while providing good target coverage. Methods: A total of 17 patients, 63 plans clinically delivered, and 252 simulated plans using Varian BrachyVision planning system were generated to investigate optimal channel configuration which results in minimum dose to bladder and rectum while providing adequate target coverage. The Capri applicator consists of 13 lumens arranged in two concentric rings, one central lumen and six lumens per ring. Manual dose shaping is invariably required to lower the dose to critical organs. Three-dimensional plans were simulated for 4 channel arrangements, all 13 channels, channel 12 o'clock (close to bladder) and 6 o'clock (close to rectum) deactivated, central channel deactivated, and central channel in addition to 12 o'clock and 6 o'clock deactivated. A relationship between V100, the volume that receives the prescribed dose, and the amount of curie-seconds required to deliver it, was established. Results: Using all 13 channels results in maximum dose to bladder and rectum. Deactivating central channel in addition to 12 o'clock and 6 o'clock resulted in minimizing bladder and rectum doses but compromised target coverage. The relationship between V100, the volume that receives the prescribed dose, and the curie seconds was found to be linear. Conclusion: Deactivating channels 12 o'clock and 6 o'clock was shown to be the optimal configuration leading to minimum dose to bladder and rectum without compromising target coverage. The linear relationship between V100 and the curie- seconds can be used as a verification parameter. more...
- Published
- 2016
- Full Text
- View/download PDF
31. A novel method of Z-contrast imaging in STEM applied to double-labelling
- Author
-
C. Ferguson, W. Tichelaar, M. Haider, Kevin Leonard, and J.‐C. Olivo
- Subjects
Histology ,Materials science ,business.industry ,Detector ,Colloidal silver ,Electron ,Contrast imaging ,Concentric ring ,Pathology and Forensic Medicine ,Angular distribution ,Optics ,Colloidal gold ,Scanning transmission electron microscopy ,business - Abstract
Summary A novel method of Z-contrast imaging in the scanning transmission electron microscope (STEM) is presented. The technique relies on the element dependence of the angular distribution of the scattered electrons, and is realized with a detector consisting of a set of concentric rings. It is possible to discriminate 9-nm colloidal gold and silver specifically distributed on thin sections. In addition to this practical work, numerical evaluations are used to assess the method. With two smaller markers, this approach will be useful in discriminating closely spaced antigenic sites when steric hindrance occurs with double-labelling using probes of different sizes. more...
- Published
- 1994
- Full Text
- View/download PDF
32. Multiprobe RLSA design for DBS reception
- Author
-
Manuel Sierra-Perez, J.L. Fernandez-Jambrina, Manuel Sierra-Castaner, and M. Vera-Isasa
- Subjects
Engineering ,Waveguide (electromagnetism) ,Field (physics) ,business.industry ,Electrical engineering ,Slot antenna ,Radial line ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Concentric ring ,Electronic, Optical and Magnetic Materials ,Optics ,Electrical and Electronic Engineering ,Antenna (radio) ,business ,Microwave ,Excitation - Abstract
A synthesis method for circular-polarization radial-line slot antennas excited by four posts inside the radial line is presented. This excitation generates a rotational mode inside the waveguide, and the slots that radiate the field can be placed arranging concentric rings. The reflected field inside the radial line can be controlled. We present the design and a prototype model for this antenna that shows practical results. © 2002 Wiley Periodicals, Inc. Microwave Opt Technol Lett 36: 70–72, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.10675 more...
- Published
- 2002
- Full Text
- View/download PDF
33. Role of sparger design in mechanically agitated gas-liquid reactors. Part I: Power consumption
- Author
-
V. B. Rewatkar and Jyeshtharaj B. Joshi
- Subjects
Materials science ,General Chemical Engineering ,Mixing (process engineering) ,Mechanical engineering ,Continuous stirred-tank reactor ,General Chemistry ,Energy consumption ,Conical surface ,Mechanics ,Industrial and Manufacturing Engineering ,Concentric ring ,Impeller ,Power consumption ,Sparging - Abstract
Power consumption (Part I) and liquid phase mixing time (Part II) were measured in 0.57, 1.0 and 1.5 m i.d. vessels. A pitched blade downflow impeller (PTD) was used. Design details of the PTD impeller such as diameter (0.22T to 0.5T), blade width (0.25D to 0.4D) and blade thickness (2.8, 4.3 and 6.4 mm) were studied. The effect of sparger type and geometry on power consumption has been investigated. For this purpose, pipe, ring, conical and concentric ring sparger were employed. Design details of the ring sparger such as ring diameter, number of holes and hole size were also studied in depth. Sparger location with respect to the impeller was found to be the most important parameter and was therefore varied for nearly all the spargers studied. A correlation for the power consumption has been developed. more...
- Published
- 1991
- Full Text
- View/download PDF
34. Magnetic resonance imaging study of the structure of the yolk in the developing avian egg
- Author
-
Martin J. Ruocco, Nikolaus M. Szeverenyi, Steven W. Falen, and David S. Packard
- Subjects
food.ingredient ,medicine.diagnostic_test ,Magnetic resonance imaging ,Avian embryo ,Embryo ,Chick Embryo ,Anatomy ,Concentric ,Biology ,Egg Yolk ,Magnetic Resonance Imaging ,Concentric ring ,food ,Yolk ,embryonic structures ,medicine ,Animals ,Animal Science and Zoology ,Blastoderm ,Mri findings ,Ovum ,Developmental Biology - Abstract
Magnetic resonance imaging (MRI) techniques were used to study the morphology of the latebra and concentric rings seen in the yolk of White Leghorn eggs during development of the avian embryo. Previous studies of the macroscopic structure of avian yolk have revealed the latebra, a vase-shaped structure beneath the blastoderm composed of white yolk. The bulbous portion in the center of the yolk is termed the body of the latebra. The thinner portion extending toward the blastoderm is referred to as the neck of the latebra. As the neck of the latebra approaches the blastoderm, it flares out to become the nucleus of Pander. The remainder of the yolk often features alternating concentric layers of white and yellow yolk. These layers, which appear as rings in sections, are thought to represent the daily accumulation of yolk during oogenesis. In this study eggs were imaged with a single slice spin echo sequence using MRI parameters that maximized the visualization of the latebra and concentric rings in the egg yolk. Some experiments were conducted for 2 to 3 day periods with eggs kept in the bore of the magnet using a small incubator that was constructed using a temperature-controlled water pump. The concentric rings of the yolk and the body of the latebra flatten and become more elliptical during development. The neck of the latebra becomes shorter and disappears around the 7th day of incubation. The body of the latebra starts to become incorporated into the embryo at about the 7th day of incubation and usually disappears by the 13th day. The concentric rings are no longer visible as distinct entities at this time. Histochemical procedures carried out as a result of MRI findings indicate that the latebra is an iron-rich structure. more...
- Published
- 1991
- Full Text
- View/download PDF
35. First report of Colletotrichum circinans causing smudge on onion in Iran
- Author
-
Sh. Bagher Abadi, Doustmorad Zafari, and S. Leylaie
- Subjects
Spots ,Health, Toxicology and Mutagenesis ,Botany ,Plant Science ,Fungal morphology ,Biology ,Pathogenicity ,Agronomy and Crop Science ,Concentric ring ,Colletotrichum circinans - Abstract
In October and November 2012, white-scaled onions bulbs with necrotic symptoms were collected in the area under cultivation in Khuzestan province. Symptoms were dark spots frequently organised in concentric rings, forming patches of up to … more...
- Published
- 2014
- Full Text
- View/download PDF
36. First report of Groundnut ringspot virus in cucumber fruits in Brazil
- Author
-
David Marques de Almeida Spadotti, Marcelo Agenor Pavan, Renate Krause-Sakate, Kelly Cristina Gonçales Rocha, and Evelynne Urzêdo Leão
- Subjects
Health, Toxicology and Mutagenesis ,Greenhouse ,Plant Science ,Biology ,biology.organism_classification ,Pathogenicity ,Concentric ring ,Virus ,Horticulture ,Capsicum annuum ,Agronomy ,Plant virus ,Pepper ,Agronomy and Crop Science ,Cucumis - Abstract
Cucumber ( Cucumis sativus ) fruits and pepper plants ( Capsicum annuum ) cultivated in the same commercial greenhouse in Vitoriana, Sao Paulo, Brazil, in December 2012 and March 2013, respectively, were found with necrotic concentric rings,… more...
- Published
- 2014
- Full Text
- View/download PDF
37. Concentric rings: an unusual presentation of tinea corporis caused by Microsporum gypseum
- Author
-
Hsin-Tsung Ho and Pei-Lun Sun
- Subjects
medicine.medical_specialty ,Infectious Diseases ,business.industry ,medicine ,Tinea capitis ,Microsporum gypseum ,Dermatology ,General Medicine ,Presentation (obstetrics) ,medicine.disease ,business ,Concentric ring - Abstract
A case of tinea corporis with the unusual presentation of concentric erythematous rings on the abdomen is reported. The pathogen was identified as Microsporum gypseum. While a number of unusual lesions have been described in M. gypseum infections, we are unaware of any reports on concentric rings. more...
- Published
- 2006
- Full Text
- View/download PDF
38. A new microstrip frequency-selective surface
- Author
-
Sudip Das, R. Bhattacharjee, S. K. Chowdhury, Santonu Sarkar, and Partha Pratim Sarkar
- Subjects
Patch antenna ,Materials science ,business.industry ,Electrical engineering ,Tunable metamaterials ,Condensed Matter Physics ,Atomic and Molecular Physics, and Optics ,Microstrip ,Concentric ring ,Electronic, Optical and Magnetic Materials ,Microstrip antenna ,Optics ,Electric field ,Electrical and Electronic Engineering ,business ,Microwave - Abstract
The frequency-selective property of a concentric ring microstrip patch with a circular patch at its center has been investigated experimentally. Measured data indicate a 16 dB dip in the normalized transmitted electric field versus frequency plotted at a particular frequency. © 2001 John Wiley & Sons, Inc. Microwave Opt Technol Lett 29: 167–168, 2001. more...
- Published
- 2001
- Full Text
- View/download PDF
39. SU-FF-T-74: Preplanning of Suture Coordinates for Episcleral Plaque Therapy
- Author
-
Melvin A. Astrahan
- Subjects
genetic structures ,medicine.diagnostic_test ,business.industry ,Posterior pole ,Fundus photography ,General Medicine ,Anatomy ,eye diseases ,Concentric ring ,Sclera ,medicine.anatomical_structure ,Optics ,Meridian (perimetry, visual field) ,Cornea ,medicine ,sense organs ,Tumor location ,business ,Geology ,Subjective observation - Abstract
Purpose: Episcleral plaques are attached to the eye by sutures which affix eyelets to the sclera. Historically, plaque position was determined by transilluminating the eye to cast a shadow of the tumor onto the sclera, outlining this shadow, and subsequently deciding where to suture the eyelets. 3D modeling enables scleral coordinates for each eyelet to be determined prior to surgery. Methods: The retinal diagram is a polar map of the retinal surface in which the posterior pole is located at the center of the map surrounded by radial spokes representing meridians and concentric rings of lattitude which terminate at the limbus which is the border of the cornea and sclera. Eyelet coordinates on an equivalent scleral diagram can be expressed using a meridian, a chord distance from the limbus along that meridian, and the chord distance between the eyelets. It is common to express diagram meridians as clock hours so coordinates for a plaque with two eyelets might be something like: eyelet ♯1 along the 12:40 o'clock meridian, 9.1 mm from the limbus, eyelet ♯2 along the 2:10 meridian 9.4 mm from the limbus, and 9.2 mm between the eyelets. Results: Over 300 patients have been treated at USC using calculated suture coordinates. Only in a handful of cases involving anterior tumors for which fundus photography was impossible was it necessary to empirically adjust coordinates. Admittedly subjective observation suggests that plaque placement to within about 8 degrees circumferentially and 0.5 mm radially of the planned position is routinely achievable. Examples will be presented. Conclusion: When the tumor location can be accurately determined from fundus photography, the placement of a plaque and its suture eyelets can be accurately preplanned. Conflict of Interest: Software which implements this technology is licensed by BEBIG GmbH for distribution under the name Plaque Simulator. more...
- Published
- 2009
- Full Text
- View/download PDF
40. 6.2: Biaxial Strength of Ultrathin AMLCD Glass Substrates
- Author
-
M. L. Hillman, John D. Helfinstine, T. A. Roe, Suresh T. Gulati, and Josef C. Lapp
- Subjects
Materials science ,Test region ,Surface strength ,Substrate (electronics) ,Fixture ,Composite material ,Active-matrix liquid-crystal display ,Membrane tension ,Concentric ring ,Weibull distribution - Abstract
The biaxial strength of ultrathin AMLCD glass substrates with thickness ranging from 0.25mm to 0.70mm was measured in the concentric ring fixture. The data, based on a large sample size of 25mm × 25mm square specimens, show that the strength is independent of glass thickness and approaches 630 MPa. The choice of 25mm × 25mm specimens for measuring the biaxial strength was dictated by minimizing large deflections and associated membrane tension in the test region. The effect of surface area under test was taken into account by using Weibull distribution which demonstrated constancy of surface strength irrespective of substrate thickness. Thus, thin and ultrathin AMLCD susbtrates have similar biaxial strength as measured in the concentric ring fixture. more...
- Published
- 2002
- Full Text
- View/download PDF
41. PINUS WOLFEI, A NEW PETRIFIED CONE FROM THE EOCENE OF WASHINGTON
- Author
-
Charles N. Miller
- Subjects
%22">Pinus ,Bract ,Paleontology ,Extant taxon ,Cone (topology) ,Thin layer ,Genetics ,Xylem ,Plant Science ,Biology ,Subgenus ,Ecology, Evolution, Behavior and Systematics ,Concentric ring - Abstract
A B S T R A C T A silicified cone from the Late Eocene of Washington is described as a new fossil species of Pinus. The cone was probably 9-10 cm long and 3-5 cm at its widest diam in the living condition and is peculiar in having abundant resin canals in the secondary xylem of the axis arranged in three concentric rings near the cone base. The bract of the fossil is also unusual in having resin canals of distinctly unequal sizes and a vascular strand that is adaxially concave. In the absence of external features of the scale tips, these anatomical conditions along with the construction of the outer cortex of the axis of thick-walled cells suggest closest affinity of the new species with the subsections Contortae, Oocarpae, and Sylvestres of the section Pinus, subgenus Pinus. THIS REPORT is based on a single silicified cone from the Late Eocene Cowlitz Formation of Washington. The specimen was found by Dr. Edward Arnold, late invertebrate paleontologist with the U. S. Geological Survey, in a bank exposure of the Cowlitz River 2.4 km east of Little Falls, Lewis County. Dr. J. A. Wolfe, U. S. Geological Survey, sent me the fossil, and the new species is named in his honor. Study of the fossil is based on ground sections.. Although some tissues were thoroughly silicified, others were porous rendering the specimen fragile. It was thus necessary to surround the cone with plastic to facilitate sawing. Cut surfaces were sealed with a thin layer of epoxy which was hardened and ground flat before gluing the surface to the slide. The new species was compared with anatomical sections of cones of thirty extant species of Pinus. more...
- Published
- 1974
- Full Text
- View/download PDF
42. Cleavage furrow formation of eggs observed with fluorescence pattern photobleaching
- Author
-
Zhang Kong-hua, Xu Cheng-tang, and Ku Kuo-yen
- Subjects
animal structures ,Shape change ,Cleavage furrow formation ,Cell Biology ,Anatomy ,Biology ,Photobleaching ,Fluorescence ,Concentric ring ,Rana ,embryonic structures ,Lateral diffusion ,Ultrastructure ,Biophysics - Abstract
Taking advantage of the extremely slow lateral diffusion of proteins on Rana amurensis egg surface (Xu et al., 1984), it was possible to make a sharp concentric ring pattern on the egg surface by photobleaching of the fluorescein-labelled egg surface. The shape change of the pattern reveals the movement of the egg surface. The surface, even in front of the furrow tip, is drawn towards the furrow centre. The furrow tip differentiates into border and central lines as shown by the distribution of surface protrusions. Between the border and central lines the nascent membrane inserts while the width of furrow tip increases to nearly 100 microns. more...
- Published
- 1988
- Full Text
- View/download PDF
43. RELATIONSHIP BETWEEN OIL DUCTS AND VOLATILE TERPENOID CONTENT IN CARROT ROOTS
- Author
-
Philipp W. Simon and Douglas Senalik
- Subjects
biology ,fungi ,Botany ,Genetics ,food and beverages ,Duct (flow) ,Plant Science ,Phloem ,biology.organism_classification ,Ecology, Evolution, Behavior and Systematics ,Concentric ring ,Terpenoid ,Daucus carota - Abstract
The number of oil ducts in freehand sections of roots of eight carrot (Daucus carota L.) genetic lines was compared to the levels of major volatile terpenoids. There was a high correlation (0.79) between number of ducts per unit area and total terpenoid amount. Individual compounds exhibited varying degrees of correlation, probably due to genetic difference between lines. Oil ducts often exhibited distinct patterns of concentric rings or radial lines, but this feature was not closely related to duct number. Oil ducts are present only in the phloem, and can form a highly interconnected network. more...
- Published
- 1986
- Full Text
- View/download PDF
44. THE CATTLE DUNG PATCH. 2. Effect of a dung patch on the chemical status of the soil, and ammonia nitrogen losses from the patch
- Author
-
B. R. Watkin and B. N. MacDiarmid
- Subjects
geography ,Animal science ,geography.geographical_feature_category ,Stolon ,Botany ,Management, Monitoring, Policy and Law ,Biology ,Agronomy and Crop Science ,Pasture ,Concentric ring - Abstract
The eifect of 1 ft-diameter (0.30 m) dung patches on the yield and botanical composition of a dairy pasture was followed in two randomized-block experiments. Experimental plots consisted of 3 concentric rings round each dung patch of diameter 2 ft (0.61 m), called R2; 3 ft (0.91 m), called R3; and 4 ft (1.22 m), called R4. They were sequentially harvested. In the first experiment described there was a significant increase in the total yield of grass species, predominantly ryegrasses, around each dung patch. This increase was first evident in R2 but spread progressively outward and was still detectable in R4. Plant material, particularly clover components, decayed rapidly beneath the dung patches. Leaving a dung patch on the pasture for 15 days kiUed 75% of the grass tillers and the rooted nodes of clover stolons; thus causing a significant reduction in pasture regrowth from the patch area when the dung patch was removed. The second experiment included three defoliation treatments, viz. 1. Cut regularly to 1 in. (2.54 cm) in all three rings; 2. Cut to 21/2 in. (6.35 cm) in R2 and 1 in. (2.54 cm) in R3 and R4; 3. Control undefoliated. In all three treatments there was a significant increase throughout the experiment in total yield of grasses around the dung patchy. The increase was confined to R2, but was still evident after 14 weeks. The greatest cumulative yield during tbe period of the experiment came from around the dung patches receiving the most intensively defoliated treatment. more...
- Published
- 1972
- Full Text
- View/download PDF
45. A REVISION OF THE GENUS SACCOGLOSSUS (ENTEROPNEUSTA) IN BRITISH WATERS
- Author
-
C. Burdon-Jones and A. M. Patil
- Subjects
biology ,Genus ,General Medicine ,Anatomy ,biology.organism_classification ,Concentric ring ,Saccoglossus ,Collar ,Proboscis (genus) - Abstract
A comparative study of topotypes of Saccoglossus ruber (Tattersall) S. serpentinus (Assheton) and S. cambrensis Brambell & Cole shows that they are conspecific, and ought henceforth all to be designated S. ruber (Tattersall). The following characteristics distinguish S. ruber from all other species of the genus:— 4 to 6 concentric rings of longitudinal fibres in the proboscis, one proboscis pore on left of stalk, proboscis 3 to 7 times the length of the collar, 45 to 95 pairs of branchial pores, 6 to 12 oesophageal pores—2 to 5 rudimentary, 5 histologically distinct regions in the collar and 3 in the oesophagus. Munsell, Ridgway and I.S.C.C.—N.S.B. colour designations for the various regions of the body have been tabulated. more...
- Published
- 1960
- Full Text
- View/download PDF
46. A report on the problem of residual solvent in solvent-extracted meals
- Author
-
A. J. Crovetto, J. J. Spadaro, E. A. Gastrock, and Ross Brian
- Subjects
Solvent ,Chromatography ,genetic structures ,Chemistry ,General Chemical Engineering ,Organic Chemistry ,Analytical chemistry ,Residual solvent ,Concentric ring - Abstract
The hazards of excess residual solvent in solventextracted meals and methods currently used for its measurement are discussed. Preliminary results are reported with a simple copper-cup flash-tester with concentric rings as heating surfaces. Solvent contents as low as 0.03% can be detected. The method is semiquantitative. The method may be useful for plant control purposes. more...
- Published
- 1960
- Full Text
- View/download PDF
47. Effects of heat shock treatment on symptom development in tobacco leaves inoculated with potato mop-top virus
- Author
-
Roger A. C. Jones
- Subjects
Potato mop-top virus ,Horticulture ,biology ,Inoculation ,Symptom development ,Tobacco mosaic virus ,biology.organism_classification ,Agronomy and Crop Science ,Virology ,Concentric ring - Abstract
SUMMARY PMTV normally causes necrotic ringspot local lesions in Xanthi-nc tobacco leaves at 15 °C but not at 22°. Dipping the leaves once in hot water at different intervals after inoculation induced necrotic reactions even at 22°. Successive concentric rings, one for each day of the interval between inoculation and treatment, were sometimes induced at 22°; these even formed in continuous lighting, suggesting an intrinsic diurnal rhythm. No lesions were induced at 22° by dipping inoculated leaves in ice-cold water. Samsun tobacco inoculated with PMTV developed very few lesions at 15°. Many more were induced however, by dipping the leaves in hot water after inoculation. The results suggest some similarities between PMTV and TMV, and the two viruses have been reported as serologically related; but PMTV did not protect plants against TMV, for TMV challenge-inoculations induced lesions within existing PMTV lesions. more...
- Published
- 1973
- Full Text
- View/download PDF
48. A NEW ENTEBOPNETJST OCCURRING IN WALES: 13. Saccoglossus cambrensis , sp. n., an Enteropneust occurring in Wales
- Author
-
F. W. Rogers Brambel
- Subjects
Epidermis (zoology) ,Ventral nerve cord ,Glomerulus ,Saccoglossus cambrensis ,General Medicine ,Anatomy ,Biology ,Branchial Region ,biology.organism_classification ,Concentric ring ,Collar ,Proboscis (genus) - Abstract
SUMMARY 1. The occurrence of an Enteropneust in Wales is described, and an account given of the environment. 2. Saccoglossus cambrensis, sp. n., is distinguished by the following characters:- Coloration; relative proportion of proboscis and collar; dorsal groove running the whole length of the proboscis, with a well-marked nervous thickening beneath; large number of gill-slits (80–90 pairs); gonads beginning a t the middle of the branchial region; absence of genital ridges; absence of projecting ridges formed by the ventral longitudinal muscle bands of the trunk; four to six concentric rings distinguishable in the arrangement of the longitudinal musculature of the proboscis; large pericardium; absence of a dorsal glomerulus; proboscis skeleton not reaching beyond the middle of the collar, and little more than half-way round the buccal cavity; five epidermal zones in the collar; complete separation of right and left collar cavities; absence of a dorsal pouch of the buccal cavity; discontinuity between the tissues of the nerve cord and the epidermis of the collar, except at the ends; collar-trunk septum deflected forwards to the middle of the collar; marked ciliation of the epidermis covering the ventral nerve cord in the intestinal region; shallow ventral pharynx; broad tongues, projecting more than the septa; histological details of the oesophagus; eight to twelve intestinal pores, of which the first three to five are rudimentary; simple unlobed gonads, large size of ova, and presence of yolk-cells in the ovaries. We are greatly indebted to Professor W. M. Tattersall and to Professor C. J. van der Horst for much advice, and to the former for specimens of S. ruber. We wish to take this opportunity of expressing our thanks also to Professor J. P. Hill, F.R.S., for his advice and interest in the work; to Professor G. W. Robinson for preparing the analyses of soil given in Appendix I.; to Mr. L. H. Jackson for assistance in various ways, and to Mrs. Jackson for the drawing reproduced in PI. I. more...
- Published
- 1939
- Full Text
- View/download PDF
49. Rasterelektronenmikroskopische Untersuchungen der Heißwasserkorrosion von Zink
- Author
-
H. Huemer and H. H. Grubitsch
- Subjects
Mechanics of Materials ,Chemistry ,Mechanical Engineering ,Materials Chemistry ,Metals and Alloys ,Environmental Chemistry ,General Medicine ,Concentric ring ,Surfaces, Coatings and Films ,Corrosion ,Nuclear chemistry - Abstract
Bei Versuchen in 0,010m Na2SO4 zeigt sich eine deutliche Abhangigkeit der Lochfras- und der Flachenkorrosion von der Temperatur. Bei 12 °C kommt es schon nach kurzer Zeit zu kraterformigem Angriff, wobei das Wachstum in Form konzentrischer Ringe erfolgt und plattchenformige Korrosionsprodukte herauswachsen. Bei 20 °C ist der Angriff narbenformig unter Bildung von immer hoher wachsenden Ringen aus kugelig-amorphem ZnO. Bei 40 °C ist der Angriff vom gleichen Typ, jedoch schon nach 5 min deutlich zu erkennen; gleichzeitig nimmt die Flachenkorrosion stark zu, wobei die einzelnen Locher mit der Zeit von zunachst amorphem und spater plattchenformigem Korrosionsprodukt uberdeckt werden. Bei 50 und 60 °C ist dieser Angriff noch deutlicher, dazu treten saulenformige Gebilde auf. Bei 70 °C uberwiegt die Flachenkorrosion und bei 80 sowie 90 °C kommt die anfanglich auftretende Lochbildung nach kurzer Zeit zum Stillstand, so das praktisch nur noch Flachenkorrosion gefunden wird. Bei 65 °C liegt ein ausgepragtes Korrosionsmaximum. Scanning electron microscope study of the hot water corrosion of zinc Experiments in 0.010m sodium sulfate solution have revealed that there is a clear temperature dependence of pitting and general corrosion. At 12 °C cratershaped corrosion is found already after a short time; pit growth is by concentric rings and plate-like corrosion products grow out of the base. At 20 °C there is a scar-type attack with annular shapes being built up by spherical amorphous ZnO. At 40 °C the attack follows the same pattern but corrosion can be recognized already after 5 min; simultaneously, there is an increase of general corrosion, the individual pits being gradually overgrown by amorphous and later plate-like corrosion product. At 50 and 60 °C this type of attack is even more pronounced and is accompanied by the formation of columnar structures. At 70 °C general corrosion predominates and at 80 and 90 °C initial pitting is stopped after a short time, so that general corrosion is practically the only type found here. At 65 °C there is a pronounced corrosion maximum. more...
- Published
- 1973
- Full Text
- View/download PDF
50. COMPUTER EVALUATION OF IRRADIATION PROCESSES IN CYLINDRICAL CONTAINERS WITH GAMMA SOURCES
- Author
-
K. S. Purohit, J. W. Zahradnik, and J. E. Manson
- Subjects
medicine.medical_specialty ,Materials science ,Computation ,Multiple integral ,Load distribution ,Mechanics ,Container (type theory) ,Concentric ring ,Distribution (mathematics) ,medicine ,Medical physics ,Irradiation ,Dose rate ,Food Science - Abstract
SUMMARY —A numerical technique is presented for evaluating food irradiation processes using cylindrical gamma sources. Dose rate distributions obtained by dividing a container into finite concentric rings permit the use of a nonuniform initial spore load distribution and the determination of both number and distribution of survivors. The double integral giving dose rates was computed using several methods. The computations gave survivors significantly different from those obtained by using approximations given in literature. Accurate evaluations require utilization of dose rate distributions in radial and axial directions. more...
- Published
- 1971
- Full Text
- View/download PDF
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.