scholarly journals Applicability of the Tanaka-Johnston method for the estimation of the mesiodistal diameter of canines and premolars in patients of 12-18 years old

2021 ◽  
pp. 1-10
Author(s):  
Laura Pereda Vázquez ◽  
Oscar Ameneiros Narciandi ◽  
Aracelys Soto Rico
Keyword(s):  
Statistical Test ◽  
X Rays ◽  
Frequency Distributions ◽  
Female Sex ◽  
Facial Pattern ◽  
Lower Incisors ◽  
The Ideal

The Tanaka-Johnston method is used worldwide to predict the diameter of canines and premolars not erupted for the convenience of not needing boards or x-rays for use. However, in recent years researchers from several countries have shown that when used in a different population for which it was designed, it can overestimate or underestimate the values. In Cuba, where the facial pattern of the population differs from the ideal for this method, it has been highly used, but there are very few studies where the reliability or accuracy of the predictions of the same is validated. Therefore, the objective of this research is to determine the applicability of the Tanaka-Johnston method for estimating the mesiodistal diameter of canines and premolars in patients aged 12-18 years. A descriptive and cross-cutting study was conducted from June 2019 to January 2020 with a population of 140 patients of both sexes between 12 and 18 years of age from Cuba. Measurements were made of the mesiodistal widths of the lower incisors, all canines, and premolars. Frequency distributions were made to the variables studied and the results were presented in statistical tables. The t-Student statistical test was used to verify significant differences. The main results obtained were that the Tanaka-Johnston method tends to overestimate the values for the female sex and underestimate them for the male, both between 0.2 and 0.3 mm, but this difference is not significant. It is concluded that the Tanaka-Johnston method can be applied in the population studied for the prediction of the mesiodistal width of unerupted canines and premolars.

A high-energy triple-axis X-ray diffractometer for the study of the structure of bulk crystals

2004 ◽  
Vol 37 (6) ◽  
pp. 901-910 ◽  
Author(s):  
C. Seitz ◽  
M. Weisser ◽  
M. Gomm ◽  
R. Hock ◽  
A. Magerl
Keyword(s):  
High Energy ◽  
X Rays ◽  
Bulk Crystals ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Intensity ◽  
High Penetration ◽  
Massive Sample ◽  
Laue Geometry ◽  
The Ideal

A triple-axis diffractometer for high-energy X-ray diffraction is described. A 450 kV/4.5 kW stationary tungsten X-ray tube serves as the X-ray source. Normally, 220 reflections of thermally annealed Czochralski Si are employed for the monochromator and analyser. Their integrated reflectivity is about ten times higher than the ideal crystal value. With the same material as the sample, and working with the WKα line at 60 keV in symmetric Laue geometry for all axes, the full width at half-maximum (FWHM) values for the longitudinal and transversal resolution are 2.5 × 10−3and 1.1 × 10−4for ΔQ/Q, respectively, and the peak intensity for a non-dispersive setting is 3000 counts s−1. In particular, for a double-axis mode, an energy well above 100 keV from theBremsstrahlungspectrum can be used readily. High-energy X-rays are distinguished by a high penetration power and materials of several centimetre thickness can be analysed. The feasibility of performing experiments with massive sample environments is demonstrated.

scholarly journals High-efficiency zone-plate optics for multi-keV X-ray focusing

2014 ◽  
Vol 21 (3) ◽  
pp. 497-501 ◽  
Author(s):  
Istvan Mohacsi ◽  
Petri Karvinen ◽  
Ismo Vartiainen ◽  
Vitaliy A. Guzenko ◽  
Andrea Somogyi ◽  
...  
Keyword(s):  
Optical Transmission ◽  
High Efficiency ◽  
Fresnel Zone ◽  
Transmission Function ◽  
Zone Plate ◽  
X Rays ◽  
Fresnel Zone Plates ◽  
X Ray ◽  
Zone Plates ◽  
The Ideal

High-efficiency nanofocusing of hard X-rays using stacked multilevel Fresnel zone plates with a smallest zone width of 200 nm is demonstrated. The approach is to approximate the ideal parabolic lens profile with two-, three-, four- and six-level zone plates. By stacking binary and three-level zone plates with an additional binary zone plate, the number of levels in the optical transmission function was doubled, resulting in four- and six-level profiles, respectively. Efficiencies up to 53.7% focusing were experimentally obtained with 6.5 keV photons using a compact alignment apparatus based on piezoelectric actuators. The measurements have also been compared with numerical simulations to study the misalignment of the two zone plates.

scholarly journals Auditory Psychophysics in Birds: the Effects of Unique Noise on Sensitivity

2021 ◽  
Author(s):  
◽  
Alan J. Taylor
Keyword(s):  
Frequency Discrimination ◽  
Frequency Distributions ◽  
Common Noise ◽  
Extraneous Noise ◽  
Alternative Approach ◽  
Masking Noise ◽  
Operant Procedure ◽  
Data Group ◽  
Measures Of Performance ◽  
The Ideal

<p>The performances of observers in auditory experiments are likely to be affected by extraneous noise from physiological or neurological sources and also by decision noise. Attempts have been made to measure the characteristics of this noise, in particular its level relative to that of masking noise provided by the experimenter. This study investigated an alternative approach, a method of analysis which seeks to reduce the effects of extraneous noise on measures derived from experimental data. Group-Operating-Characteristic (GOC) analysis was described by Watson (1963) and investigated by Boven (1976). Boven distinguished between common and unique noise. GOC analysis seeks to reduce the effects of unique noise. In the analysis, ratings of the same stimulus on different occasions are sunned. The cumulative frequency distributions of the resulting variable define a GOC curve. This curve is analogous to an ROC curve, but since the effects of unique noise tend to be averaged out during the summation, the GOC is less influenced by extraneous noise. The amount of improvement depends on the relative variance of the unique and common noise (k). Higher levels of unique noise lead to greater improvement. In this study four frequency discrimination experiments were carried out with pigeons as observers, using a three-key operant procedure. In other experiments, computer-simulated observers were used. The first two pigeon experiments, and the simulations, were based on known distributions of common noise. The ROCs for the constructed distributions provided a standard with which the GOC curve could be compared. In all cases the analysis led to improvements in the measures of performance and increased the match of the experimental results and the ideal ROC. The amount of improvement, as well as reflecting the level of unique noise, depended on the number of response categories. With smaller numbers of categories, improvement was reduced and k was underestimated. Since the pigeon observers made only "yes" or "no" responses, the results for the pigeon experiments were compared with the results of simulations with known distributions in order to obtain more accurate estimates of k. The third and fourth pigeon experiments involved frequency discrimination tasks with a standard of 450 Hz and comparison frequencies of 500, 600, 700, 800 and 900 Hz, and 650 Hz, respectively. With the multiple comparison frequencies the results were very variable. This was due to the small number of trials for each frequency and the small number of replications. The results obtained with one comparison frequency were more orderly but, like those of the previous experiment, were impossible to distinguish from those which would be expected if there was no common noise. A final set of experiments was based on a hardware simulation. Signals first used in the fourth pigeon experiment were processed by a system made up of a filter, a zero-axis crossing detector and a simulated observer. The results of these experiments were compatible with the possibility that the amount of unique noise in the pigeon experiments overwhelmed any evidence of common noise.</p>

Illustrated Questions in Orthodontics

2014 ◽  
Author(s):  
Claire Nightingale ◽  
Jonathan Sandy
Keyword(s):  
Treatment Planning ◽  
X Rays ◽  
Clinical Context ◽  
High Quality ◽  
The Ideal

Illustrated Questions in Orthodontics takes a problem-based approach to orthodontics, offering a unique resource for undergraduate dentists. This book contains a comprehensive set of questions mapped to undergraduate orthodontics curricula, including chapters on examination and diagnosis, treatment planning, pathology, appliances, and anchorage. Each chapter is packed with high-quality clinical photographs and x-rays to help readers to test their skills in identifying and describing various orthodontic problems and presentations. Furthermore, every question is answered with extensive feedback, setting each topic in a clinical context in order to teach as well as test. The ideal revision resource for undergraduate dentists looking to test and consolidate their knowledge ahead of placements and exams, Illustrated Questions in Orthodontics will also form a useful tool for postgraduate dentists and orthodontic therapists.

Impaired Osseous Wound Healing Following Ionizing Irradiation Is Ameliorated by Mitochondrial Targeted Nitroxide JP4-039.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4576-4576
Author(s):  
Jean-Claude Rwigema ◽  
Abhay Gokhale ◽  
Julie Glowacki ◽  
Tracy Dixon ◽  
Ken Patrene ◽  
...  
Keyword(s):  
Wound Healing ◽  
Wound Repair ◽  
Bone Repair ◽  
Statistical Test ◽  
Multiple Comparison ◽  
X Rays ◽  
Ionizing Irradiation ◽  
Total Body ◽  
The Right

Abstract Abstract 4576 In the case of a nuclear explosion, combined injuries may include ionizing irradiation and bone fracture. We evaluated the potential bone wound healing stimulation capacity of a new mitochondrial targeted nitroxide - JP4-039 - that was developed and demonstrated to protect against total body irradiation. JP4-039 was synthesized by coupling Tempol (4-hydroxy-2,2,6,6-tertamethylpiperidine-N-oxyl) and a novel alkene isotere analog of a gramicidin S (GS) fragment. JP4-039 is now being tested to determine whether it can also improve osseous wound healing. A model for osseous wound healing was used in the right hind leg of C57BL/6NHsd female mice and irradiated in doses ranging from 0 to 30 Gy, then holes drilled in both tibias 24 hr later. The mice were sacrificed at 7, 14, 21, 28 or 35 days. Tibial wounding and x-rays were used for determination of wound size. The bones were fixed, sectioned, and examined for osseous wound repair. A significant irradiation- induced delay in wound repair (hole diameter) was detected at 21 days in both the 20 Gy (0.93 ± 0.11 mm, p=0.008) and 30 Gy (1.1 ± 0.1 mm, p=0.0002) groups, compared with the 0 Gy group (0.67 ± 0.23 mm). At 28 days, there were statistically significant increased hole diameters between each irradiation groups (10 Gy, 0.76 ± 0.08 mm, p=0.003; 20 Gy, 0.87 ± 0.36 mm, p=0.04; 30 Gy, 0.76 ± 0.22 mm, p=0.02) and the 0 Gy group (0.32 ± 0.32 mm). By day 35, the wounds in the 0 Gy group were healed (0.08 ± 0.17 mm), while wounds in the 20 Gy group (0.22 ± 0.24 mm, p=0.02) and 30 Gy group (0.34 ± 0.23 mm, p=0.001) remained significantly larger. To determine whether JP4-039 improved the time of osseous wound healing, mice were injected intraperitoneally with JP4-039 (10 mg/kg) 10 min before drilling holes in both rear legs. Mice injected with JP4-039 before drilling showed significant improvement in osseous wound healing in 14 days and 21 days after drilling (0.55 ± 0.3 and 0.47 ± 0.04 mm, respectively), compared with 0.84 ± 0.05 and 0.64 ± 0.05 mm, respectively for control mice (p < 0.05 according to Tukey's multiple comparison statistical test). To test whether JP4-039 can improve osseous wound healing in irradiated limbs, mice were injected with JP4-039 (10 mg/kg) 10 min before 20 Gy to the right hind leg. Wounds were made in both tibae 24 hr after irradiation. At 21 and 28 days after wounding, bones from JP4-039 treated-irradiated mice displayed improved healing with holes of 0.51 ± 0.05 and 0.37 ± 0.04 mm, respectively, compared with 1.01 ± 0.10 and 0.76 ± 0.13 mm, respectively, for control irradiated bones. This is significant at < 0.05 as calculated using a Tukey's multiple comparison statistical test. Histopathological evaluation of specimens from mice pre-treated with JP4-039 prior to irradiation confirmed radiographic evidence of improved healing. Thus, JP4-039 enhances bone repair and is effective in a combined irradiation injury setting. Supported by NIAID/NIH grant U19AI068021 and BARDA Contract HHSO10200800062C. Disclosures: Roodman: Novartis: Consultancy, Research Funding, Speakers Bureau; Amgen: Consultancy; Celgene: Consultancy; Acceleron: Consultancy.

The effect of particles on the absorption factor for diffracted X-rays in single-phase powders measured at cylindrical geometry— a computational study

1998 ◽  
Vol 13 (4) ◽  
pp. 249-253
Author(s):  
J. Collazo ◽  
H. Hermann ◽  
A. Teresiak ◽  
K. Wetzig
Keyword(s):  
Single Phase ◽  
Fine Particles ◽  
Computational Study ◽  
X Rays ◽  
Absorption Factor ◽  
Linear Absorption Coefficient ◽  
Linear Absorption ◽  
Powder Particles ◽  
Dense Packings ◽  
The Ideal

The results of computer simulations of the absorption of diffracted X-rays in single-phase powders measured at cylindrical (or Debye–Scherrer capillary) geometry taking into consideration the size of the powder particles are presented. The samples are simulated by random dense packings of equal spheres. The calculations are carried out for different values of the ratio, Da, of particle size to cylinder diameter, the product, κ, of linear absorption coefficient and cylinder radius and the scattering angle 2θ. Strong deviations of the absorption factor from the values for the ideal case of very fine particles are found in the region 0≤2θ≤30°, and for medium and high values of κ,(κ≥5) and Da (Da≥0.002). The consequences for the experiment are discussed.

scholarly journals Strategies of space occupation by anchovy and sardine in the southern Benguela: the role of stock size and intra-species competition

2005 ◽  
Vol 62 (4) ◽  
pp. 645-654 ◽  
Author(s):  
Manuel Barange ◽  
Janet C. Coetzee ◽  
Nandipha M. Twatwa
Keyword(s):  
Relative Increase ◽  
High Density ◽  
High Biomass ◽  
Frequency Distributions ◽  
Stock Size ◽  
Indicator Variables ◽  
Space Occupation ◽  
Very High ◽  
The Ideal

Abstract Strategies of space occupation by anchovy and sardine populations in the southern Benguela during cruises in 1994 (low biomass) and 2001 (high biomass) are investigated using geostatistical tools. The spatial expansion of anchovy and sardine during the high-density year resulted in an increase in the number and density of hotspots and, in the case of anchovy, a relative increase in the contribution of mid- to high-density intervals to the overall survey biomass. Variogram autocorrelation ranges were larger in the high-biomass year. Otherwise, similarities and differences in the strategies of space occupation between anchovy and sardine are consistent between years of low and high biomass, and are therefore density-independent. Variograms of indicator variables revealed comparable structures for both species and years, with autocorrelation ranges of 30 nautical miles for the smallest indicator (0.1 g m−2) and 10 miles for the largest (100 g m−2), reflecting intrinsic spatial structures independent of stock size. The ideal survey inter-transect distance, defined as the autocorrelation range of the highest density indicator, was not influenced by the expanded distribution of both species. Cumulative frequency distributions and cross-variograms revealed differences in space occupancy between both species. Despite the areal expansion, and in contrast to anchovy, a significant portion of the sardine biomass continued to be contributed by a few very high-density areas with little spatial structure, as indicated by large nugget effects in the variograms and lack of transitions in the cross-variograms. Both species were spatially segregated in the low-biomass year, but overlapped extensively in the high-biomass year.

scholarly journals Effects of the Ratio between Pigment and Bleaching Gel on the Fracture Resistance and Dentin Microhardness of endodontically treated Teeth

2017 ◽  
Vol 18 (11) ◽  
pp. 1051-1055 ◽  
Author(s):  
Matheus Coelho Bandeca ◽  
Milton C Kuga ◽  
Keren CF Jordão-Basso ◽  
Mateus R Tonetto ◽  
Marina OG Galloza ◽  
...  
Keyword(s):  
Fracture Resistance ◽  
The Other ◽  
Tooth Bleaching ◽  
Endodontically Treated Teeth ◽  
Lower Incisor ◽  
Dental Bleaching ◽  
Dental Crowns ◽  
Resistance Reduction ◽  
Lower Incisors ◽  
The Ideal

ABSTRACT Introduction The aim of this study was to evaluate the effects of bleaching gel using 35% hydrogen peroxide (HP), associated with red carmine pigment (RC), in the 3:1 or 1:1 ratio, on fracture resistance and dentin microhardness of endodontically treated teeth. Materials and methods A total of 40 lower incisors were endodontically treated and divided into four groups (n = 10), according to the bleaching protocol: G1 (HP3), 35% HP + RC (3:1); G2 (HP1), 35% HP + RC (1:1); G3 (positive), 38% HP; and G4 (negative), unbleached. Four dental bleaching sessions were performed. The dental crowns were restored after the last session and submitted to the fracture resistance test. Totally, 60 specimens from the endodontically treated lower incisor crowns were prepared to evaluate the effects on dentin microhardness. The analysis was measured (in Knoop) prior to and after the last dental bleaching session using similar bleaching protocols. Results G2 presented the lowest fracture resistance (p < 0.05). The other groups were similar to each other (p > 0.05). No difference was observed in the reduction of dentin microhardness among the groups (p > 0.05). Conclusion A 1:1 ratio (bleaching gel:pigment) caused a significant fracture resistance reduction in relation to the other protocols. No effect on the dentin microhardness reduction was observed. Clinical significance The pigment addition to the bleaching agent accelerates the bleaching chemical reaction. However, no studies have evaluated the ideal proportion to optimize tooth bleaching. How to cite this article Galloza MOG, Jordão-Basso KCF, Bandeca MC, Costa SO, Borges AH, Tonetto MR, Tirintan FC, Keine KC, Kuga MC. Effects of the Ratio between Pigment and Bleaching Gel on the Fracture Resistance and Dentin Microhardness of endodontically treated Teeth. J Contemp Dent Pract 2017;18(11):1051-1055.

scholarly journals An Assessment of the Interoperability of Electronic Health Record Exchanges Among Hospitals and Clinics in Taiwan (Preprint)

2018 ◽  
Author(s):  
Hsyien-Chia Wen ◽  
Wei-Pin Chang ◽  
Min-Huei Hsu ◽  
Cheng-Hsun Ho ◽  
Chi-Ming Chu
Keyword(s):  
Medical Records ◽  
Medical Images ◽  
Statistical Test ◽  
X Rays ◽  
Medical Needs ◽  
Medical Centers ◽  
District Hospitals ◽  
Significant Difference ◽  
Electronic Health ◽  
Discharge Summaries

BACKGROUND The rapid aging of the Taiwanese population in recent years has led to high medical needs for the elderly and increasing medical costs. Integrating patient information through electronic health records (EHRs) to reduce unnecessary medications and tests and enhance the quality of care has currently become an important issue. Although electronic data interchanges among hospitals and clinics have been implemented for many years in Taiwan, the interoperability of EHRs has not adequately been assessed. OBJECTIVE The study aimed to analyze the efficiency of data exchanges and provide suggestions for future improvements. METHODS We obtained 30 months of uploaded and downloaded data of EHRs among hospitals and clinics. The research objects of this study comprised 19 medical centers, 57 regional hospitals, 95 district hospitals, and 5520 clinics. We examined 4 exchange EHR forms: laboratory test reports, medical images, discharge summaries, and outpatient medical records. We used MySQL (Oracle Corporation) software (to save our data) and phpMyAdmin, which is a Personal Home Page program, to manage the database and then analyzed the data using SPSS 19.0 statistical software. RESULTS The quarterly mean uploaded volume of EHRs among hospitals was 52,790,721 (SD 580,643). The quarterly mean downloaded volume of EHRs among hospitals and clinics was 650,323 (SD 215,099). The ratio of uploaded to downloaded EHRs was about 81:1. The total volume of EHRs was mainly downloaded by medical centers and clinics, which accounted for 53.82% (mean 318,717.80) and 45.41% (mean 269,082.10), respectively, and the statistical test was significant among different hospital accreditation levels (F2=7.63; P<.001). A comparison of EHR download volumes among the 6 National Health Insurance (NHI) branches showed that the central NHI branch downloaded 11,366,431 records (21.53%), which was the highest, and the eastern branch downloaded 1,615,391 records (3.06%), which was the lowest. The statistical test among the 6 NHI branches was significant (F5=8.82; P<.001). The download volumes of laboratory tests reports and outpatient medical records were 26,980,425 (50.3%) and 21,747,588 records (40.9%), respectively, and were much higher than medical images and discharge summaries. The statistical test was also significant (F=17.72; P<.001). Finally, the download time showed that the average for x-rays was 32.05 seconds, which was the longest, and was 9.92 seconds for electrocardiogram, which was the shortest, but there was no statistically significant difference among download times for various medical images. CONCLUSIONS After years of operation, the Electronic Medical Record Exchange Center has achieved the initial goal of EHR interoperability, and data exchanges are running quite stably in Taiwan. However, the meaningful use of EHRs among hospitals and clinics still needs further encouragement and promotion. We suggest that the government’s leading role and collective collaboration with health care organizations are important for providing effective health information exchanges.

scholarly journals A complete sample of LSP blazars fully described in γ-rays

2018 ◽  
Vol 616 ◽  
pp. A20 ◽  
Author(s):  
B. Arsioli ◽  
G. Polenta
Keyword(s):  
Peak Power ◽  
Spectral Energy Distribution ◽  
High Energy ◽  
Spectral Energy ◽  
Full Description ◽  
X Rays ◽  
Test Statistic ◽  
Complete Sample ◽  
Frequency Distributions ◽  
Source Confusion

Context. We study the γ-ray and broadband spectral energy distribution (SED) properties of a complete sample of 104 bright, radio-selected low-synchrotron peaked (LSP) blazars, which have well-characterized SEDs from radio to X-rays. Most of the sources have already been detected in the γ-ray band by Fermi-LAT, however almost 20% of these blazars have no counterpart in any of the Fermi catalogs published so far. Aims. Using the Fermi Science Tools, we look for γ-ray emission for those objects not yet reported in any Fermi-LAT catalog, finding new detections and associations. We then study the multifrequency SED for all sources in our sample, fitting their synchrotron (Syn) and inverse Compton (IC) components. A complete sample of LSP blazars with a full description in γ-ray is unique. We use this sample to derive the distribution of the Compton dominance (CD) along with population properties such as Syn and IC peak power, and frequency distributions. Methods. We performed a binned likelihood analysis in the 0.3–500 GeV energy band with Fermi-LAT Pass 8 data, integrating over 7.5 yr of observations. We studied γ-ray light curves and test statistic (TS) maps to validate new detections and associations, thereby building a better picture of the high-energy activity in radio-selected LSP blazars. We fit the IC component for the new detections using all data at our disposal from X-rays to GeV γ-rays, enhancing the amount of information available to study the Syn to IC peak-power correlations. Results. We deliver a unique characterization in γ-rays for a complete sample of LSP blazars. We show that three previously unidentified 3FGL sources can be associated with blazars when using improved γ-ray positions obtained from TS maps. Six previously unreported γ-ray sources are detected at TS > 20 level, while another three show TS values between 10–20. We evaluate two cases in which source confusion is likely present. In four cases there is no significant γ-ray signature when integrating over 7.5 yr. Short-lived flares at ~1 month scale, however, have been detected in these sources. Finally, we measure the log(CD) for the sample, which has a Gaussian-like distribution with median log(CD) ≈ 0.1, implying that on average the peak-power for the Syn and IC components in LSP blazars is similar.

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