bluuebunny/crossref_metadata_2025 huggingface dataset:
Machine conquest: Jules Verne’s technocratic worldmaking
Authors: Eijking Jan
Published: October 2024

This article reads Jules Verne’s Extraordinary Voyages series (1863–1905) through a worldmaking lens. It argues that, rather than simply reflecting 19th-century ideologies of progress, Verne was engaged in creative global ordering. The article argues that Verne constructed global order as technocratic, anti-political, and necessarily violent. This space was ambiguously but persistently appropriated by white, male engineers and scientists. This generates two important insights for International Relations (IR). First, Verne’s global order was not about states, sovereignty, or political community: it was about an elite vanguard of technocratic adventurers roaming the globe. At a time when colonial incursions frequently emerged out of interventions by explorers and engineers and other ‘people with projects’, this understanding resonated deeply. It is also worth recovering as a current of technocratic thought not centred on bureaucracy and strong government but on private enterprise. Second, Verne’s fiction constituted a powerful conception of global order, and contemporaries drew upon this as an inspiration for real-world interventions. At the French Société de Géographie, of which Verne was a long-time member, as well as among imperialists across Europe, the Voyages became a casual frame of reference in justification of colonial expansion. Better understanding this typically downplayed aspect of the modern international imagination not only promises to enrich IR’s understanding of the role of speculative fiction in global ordering but also puts the current revival of techno-colonial projects – from Seasteading to the colonisation of Mars – into needed perspective.
Intuition and Kagan's Hierarchicalism
Authors: Ouyang Xihe
Published: October 2024

According to Shelly Kagan, the moral status of an individual is determined by the extent to which the individual has (has now, might/will have, or could have had) certain psychological capacities. Roughly speaking, the greater one's relevant psychological capacities, the higher their moral status. In this paper, I offer a twofold critique of Kagan's hierarchicalism. On the one hand, I argue against the primary argument in favor of Kagan's view (the argument from distribution) by challenging the key intuition on which the argument relies, thereby reducing the appeal of Kagan's position. On the other hand, using Kagan's general methodology, I argue that a good reason to reject Kagan's account of moral status is that he fails to explain away the counterintuitive result of his theory in the case of normal variation.
Lung volumes are increased in fetuses with transposition of the great arteries on intrauterine MRI
Authors: Krogh Emil , Ringgaard Steffen , Kelly Benjamin , Rungsiprakarn Phassawan , Rychik Jack , Gaynor J. William , Biko David M. , Hjortdal Vibeke , Lauridsen Mette Høj
Published: October 2024

Fetal brain size is decreased in some children with complex CHDs, and the distribution of blood and accompanying oxygen and nutrients is regionally skewed from early fetal life dependent on the CHD. In transposition of the great arteries, deoxygenated blood preferentially runs to the brain, whereas the more oxygenated blood is directed towards the lungs and the abdomen. Knowledge of whether this impacts intrauterine organ development is limited. We investigated lung, liver, and total intracranial volume in fetuses with transposition of the great arteries using MRI.

Eight fetuses with dextro-transposition and without concomitant disease or chromosomal abnormalities and 42 fetuses without CHD or other known diseases were scanned once or twice at gestational age 30 through 39 weeks. The MRI scans were conducted on a 1.5T system, using a 2D balanced steady-state free precession sequence. Slices acquired covered the entire fetus, slice thickness was 10 mm, pixel size 1.5 × 1.5 mm, and scan duration was 30 sec.

The mean lung z score was significantly larger in fetuses with transposition compared with those without a CHD; mean difference is 1.24, 95% CI:(0.59;1.89), p < 0.001. The lung size, corrected for estimated fetal weight, was larger than in the fetuses without transposition; mean difference is 8.1 cm3/kg, 95% CI:(2.5;13.7 cm3/kg), p = 0.004.

In summary, fetuses with dextro-transposition of the great arteries had both absolute and relatively larger lung volumes than those without CHD. No differences were seen in liver and total intracranial volume. Despite the small number of cases, the results are interesting and warrant further investigation.
Social cognition in adults with neurofibromatosis type 1
Authors: Remaud Julie , Besnard Jérémy , Barbarot Sébastien , Roy Arnaud
Published: October 2024

Objective:

Adult patients with the genetic disease neurofibromatosis type 1 (NF1) frequently report social difficulties. To date, however, only two studies have explored whether these difficulties are caused by social cognition deficits, and these yielded contradictory data. The aim of the present study was to exhaustively assess social cognition abilities (emotion, theory of mind, moral reasoning, and social information processing) in adults with NF1, compared with a control group, and to explore links between social cognition and disease characteristics (mode of inheritance, severity, and visibility).

Method:

We administered a social cognition battery to 20 adults with NF1 (mean age = 26.5 years, SD = 7.4) and 20 healthy adults matched for sociodemographic variables.

Results:

Patients scored significantly lower than controls on emotion, theory of mind, moral reasoning, and social information processing tasks. No effects of disease characteristics were found.

Conclusions:

These results appear to confirm that adults with NF1 have a social cognition weaknesses that could explain, at least in part, their social difficulties, although social abilities are not all impaired to the same extent. Regarding the impact of the disease characteristics, the patient sample seemed slightly insufficient for the power analyses performed. Thus, this exploratory study should form the basis of further research, with the objective of replicating these results with larger and more appropriately matched samples.
The Origin of Magnetofossil Coercivity Components: Constraints From Coupled Experimental Observations and Micromagnetic Calculations
Authors: Xue Pengfei , Chang Liao , Pei Zhaowen , Harrison Richard J.
Published: October 2024

Biogenic magnetite crystals produced by magnetotactic bacteria (MTB) and associated magnetofossils in sediments are characterized by variable morphologies, grain sizes, and chain structures. Magnetofossils are widely used in paleomagnetic and paleoenvironmental studies, but the complex magnetofossil shapes and particle arrangements significantly affect magnetic properties, hampering their magnetic detection and proxy interpretation. Here we perform coupled experimental and micromagnetic modeling analyses of typical magnetofossil‐rich sediments, where the effects of magnetofossil crystal forms and microstructures on magnetic properties can be quantitatively separated. Since the in situ magnetofossil chain structures in sediments remain poorly known, we compare results from magnetic measurements and micromagnetic simulations based on realistic magnetofossil shapes and grain size distributions. Our results suggest that bullet‐shaped magnetofossils certainly contribute to the biogenic hard (BH) coercivity component with a minor contribution from elongated prismatic particles, and collapsed equidimensional grains to the biogenic soft (BS) component. Micromagnetic simulations with different collapse models of bullet‐shaped magnetofossils produce variable FORC (first‐order reversal curve) central‐ridge contributions with similar coercivity distributions. Sensitivity test suggests that samples containing different forms of magnetofossils can produce the BH coercivity component if the proportion of the bullet‐shaped particles is more than ∼2%. Magnetofossil assemblages with a higher proportion of bullet‐shaped particles have higher coercivities, squareness ratios, and larger BH contents. Our data shed new light on understanding the origin of magnetofossil coercivity components and the in situ magnetofossil microstructures in sediments, which is widely useful for interpreting magnetofossil proxy signals in geological records.
Physics‐Informed Neural Networks for the Augmented System of Shallow Water Equations With Topography
Authors: Dazzi Susanna
Published: October 2024

Physics‐informed neural networks (PINNs) are gaining attention as an alternative approach to solve scientific problems governed by differential equations. This work aims at assessing the effectiveness of PINNs to solve a set of partial differential equations for which this method has never been considered, namely the augmented shallow water equations (SWEs) with topography. Differently from traditional SWEs, the bed elevation is considered as an additional conserved variable, and therefore one more equation expressing the fixed‐bed condition is included in the system. This approach allows the PINN model to leverage automatic differentiation to compute the bed slopes by learning the topographical information during training. PINNs are here tested for different one‐dimensional cases with non‐flat topography, and results are compared with analytical solutions. Though some limitations can be highlighted, PINNs show a good accuracy for the depth and velocity predictions even in the presence of non‐horizontal bottom. The solution of the augmented system of SWEs can therefore be regarded as a suitable alternative strategy to deal with flows over complex topography using PINNs, also in view of future extensions to realistic problems.
Local and Remote Effects of the Sub‐Grid Turbulent Orographic Form Drag on the Summer Monsoon Precipitation Over Eastern China
Authors: Zhou Yuchen , Huang Anning , Li Xin , Gu Chunlei , Wu Yang
Published: October 2024

The sub‐grid turbulent orographic form drag (STOFD) significantly affects the regional circulation and precipitation. This study explores the local and remote effects of the STOFD on the summer monsoon precipitation across Eastern China using the Regional Climate Model Version 4 adopting a STOFD scheme. Results indicate that the local and remote effects of the STOFD primarily influence the improvement of summer precipitation simulation in the Southeastern and Northern China, respectively. The local effects of the STOFD can lead to 37.1% and 10.7% reduction of the absolute error and the root mean square error (RMSE) of simulated summer precipitation in the Southeastern China with complex sub‐grid terrains. The remote effects of the STOFD within the Indochina Peninsula and Yunnan‐Guizhou Plateau result in the absolute error and RMSE of simulated summer precipitation in the Northern China with mild sub‐grid terrain decreased by 90.1% and 32.9%, respectively. Moreover, the remote effects of the STOFD within the Tianshan Mountains and Tibetan Plateau can clearly improve the simulated precipitation in both the Southeastern and Northern China. The disturbances generated by the local effects of the STOFD are more locally concentrated than those produced by the STOFD remote effects, leading to a more significant improvement of precipitation simulation in the Southeastern China. While the disturbances resulted from the remote effects of the STOFD affect the summer precipitation in both the Southeastern and Northern China obviously. This study highlights the significance of the remote effects of the STOFD in improving the summer precipitation simulation in Eastern China.
Temperature and Flow Control Organic Carbon Metabolism in Boreal Headwater Streams
Authors: Iannucci F. M. , Jones J. B. , Olson K. L. , Muscarella M. E. , Hotchkiss E. R.
Published: October 2024

Metabolism in stream ecosystems alters the fate of organic carbon (OC) received from surrounding landscapes, but our understanding of in‐stream metabolic processes in boreal ecosystems remains limited. Determining the factors that regulate OC metabolism will help predict how the C balance of boreal streams may respond to future environmental change. In this study, we addressed the question: what controls OC metabolism in boreal headwater streams draining catchments with discontinuous permafrost? We hypothesized that metabolism is collectively regulated by OC reactivity, phosphorus availability, and temperature, with discharge modulating each of these conditions. We tested these hypotheses using a combination of laboratory experiments and whole‐stream ecosystem metabolism measurements throughout the Caribou‐Poker Creeks Research Watershed (CPCRW) in Interior Alaska, USA. In the laboratory experiments, respiration and dissolved OC (DOC) removal were both co‐limited by the supply of reactive C and phosphorus, but temperature and residence time acted as stronger controls of DOC removal. Ecosystem respiration (ER) was largely predicted by discharge and site, with some variance explained by gross primary production (GPP) and temperature. Both ER and GPP varied inversely with watershed permafrost extent, with an inverse relationship between temperature and permafrost extent providing one plausible explanation. Our results provide some of the first evidence of a functional response to permafrost thaw in stream ecosystems and suggest the role of metabolism in landscape C cycling may increase as climate change progresses.
Development of the Chinese Dual Auroral Radar Network and Preliminary Results
Authors: Zhang Jiaojiao , Lan Ailan , Yan Jingye , Deng Xiang , Wang Wei , Li Hang , Sun Lingchen , Nan Ying , Song Xiaochao , Wang Chi
Published: October 2024

Led by the National Space Science Center of the Chinese Academy of Sciences, we have built a Chinese dual auroral radar network in northern China, which is called the CN‐DARN. The CN‐DARN consists of three pairs of high‐frequency coherent scattering radar facilities and is one of the key parts of the Chinese Meridian Project Phase II. It has been fully constructed and started trial operations at the end of 2023. The detection range of the radar network extends longitudinally over approximately 9 hr of local times and covers the middle to high latitudes of the entire Asia region above 40. In this paper, we present the basic design of the CN‐DARN and its preliminary observations of ionospheric irregularities, subauroral polarization streams (SAPSs) and traveling ionospheric disturbances (TIDs). We also investigate its contribution to the ionospheric convection pattern of the Northern Hemisphere derived from Super Dual Auroral Radar Network (SuperDARN) observations. The results indicate that the CN‐DARN provides excellent measurements and better specifications of flows in the Asian sector, improving our understanding of the global‐scale ionospheric convection pattern in the Northern Hemisphere. These encouraging results lead us to believe that the CN‐DARN will play an important role in studies on the evolution of ionospheric irregularities, the characteristics and evolution of SAPSs, the propagation of TIDs, and global‐scale ionospheric convection dynamics.
Community structure of tropics emerging from spatio-temporal variations in the Intertropical Convergence Zone dynamics
Authors: Chopra Gaurav , Unni Vishnu R. , Venkatesan Praveenkumar , Vallejo-Bernal Sara M. , Marwan Norbert , Kurths Jürgen , Sujith R. I.
Published: October 2024

The Intertropical Convergence Zone (ITCZ) is a narrow tropical belt of deep convective clouds, intense precipitation, and monsoon circulations encircling the Earth. Complex interactions between the ITCZ and local geophysical dynamics result in high climate variability, making weather forecasting and prediction of extreme rainfall or drought events challenging. We unravel the complex spatio-temporal dynamics of the ITCZ and the resulting teleconnection patterns via a novel tropical climate classification achieved using complex network analysis and community detection. We reduce the high-dimensional complex ITCZ dynamics into a simple yet insightful community structure that classifies the tropics into seven regions representing distinct ITCZ dynamics. The two largest communities, encompassing landmasses over the Northern and Southern hemispheres, are associated with coherent seasonal ITCZ dynamics and have significant long-range connections. Temporal analysis of the community structure highlights that the tropical Pacific and Atlantic Oceans communities exhibit substantial variation on multidecadal scales. Further, these communities exhibit incoherent dynamics due to atmosphere-ocean interactions driven by equatorial and coastal oceanic upwelling.
Complications associated with loop ileostomy reversal delayed greater than twelve months
Authors: Cai Jinman , Denison Madaliene , Sharp Hunter , Edelson Mia , Kwok James , Scarbro Molly , Adkins Farrell
Published: October 2024

Diverting loop ileostomy is performed after colectomy to allow for anastomotic healing, and prevention of pelvic sepsis when an anastomotic leak occurs. There is no consensus on the optimal timing of ileostomy closure, and there is limited data on complications associated with ileostomy closure greater than 12 months after creation. The aim of this study is to investigate outcomes of delayed loop ileostomy closure greater than 12 months after creation. Patients undergoing loop ileostomy closure between 2013 and 2023 at Carilion Medical Center, in Roanoke, VA were reviewed. Cohorts compared were defined as Control Group (closure < 4 months) and Delayed Group (closure > 12 months). Demographics and outcomes were compared. Statistical comparisons were performed using either Wilcoxon rank sum test, Pearson’s Chi-squared test or Fisher’s exact test. Statistical modeling included binary logistic regression for 30-day readmissions and a generalized linear modeling for days till bowel function returns. Adjusted odds ratios, confidence intervals, and p-values were calculated. There were 135 patients in the Control Group and 19 patients in the Delayed Group. Demographics were similar between the groups except for a higher percentage of patients with diabetes, renal failure and history of cancer in Delayed Group (all p < 0.05). Operative time was longer for Delayed loop ileostomy closure (p < 0.05). Patients in the Delayed Group demonstrated a higher hospital readmission rate within 30 days (p < 0.05). Both groups had similar return of bowel function on post-operative day 2, similar length of stay, and similar rates of postoperative ileus (p = NS). Delayed loop ileostomy closure more than 12 months after creation does not delay return of bowel function but may lead to higher hospital readmission rates within 30 days.
Research on fractional-order memory system signals based on Loop-By-Loop Progressive Iterative Method
Authors: Xu Li , Huang Chuan , Huang Guo , He Duyi
Published: October 2024

This article abandons the traditional Laplace transform and proposes a new method for studying fractional-order circuits, which is the Loop-By-Loop Progressive Iterative Method(LPIM). Firstly, in order to demonstrate the correctness of LPIM, the fractance circuit, which is a relatively mature and simple form in fractional-order circuits, was chosen as the research object. The output signals of fractance circuit were studied for the first time using Laplace transform and LPIM, respectively. The results showed that the conclusions obtained by LPIM were completely consistent with those obtained by Laplace transform method and existing theories, thus verifying the correctness of LPIM. Then, a brand new Fractional-Order Memory Systems (FMS) model is constructed, and based on this model, LPIM is used for the first time to simulate the output signal of Flux-Controlled Fractional-Order Memory Systems (FFMS) that has not been studied so far. The results show that when a sine signal is used as the excitation signal, the output signal of the FFMS intersects at two points, and the output signal is modulated by the frequency of the excitation signal. Finally, combining existing theories, predict the output commonalities of FMS.
Thermology and facial telethermography. Part I: History and technical review
Authors: Anbar M , Gratt B M , Hong D
Published: October 2024

This paper is a review of historical trends and technical advances in measurement of skin temperature. Most biochemical processes generate heat which must be dissipated. Skin is the major route for heat dissipation using blood as the heat exchange fluid. Skin temperature is an indicator of aberrations in metabolism, hemodynamics or in neuronal thermoregulatory processes. Since most of the heat dissipation of skin is by infrared blackbody emission, skin temperature should be measured without contact by monitoring the emitted infrared radiation. This has been the basis of telethermography. Recent advances in computing technology combined with advanced infrared sensor technology has led to the development of dynamic area telethermometry (DAT) which promises to be as an important new quantitative method to analyse the pathophysiology of thermoregulatory processes.
The influence of radiographic exposure factors on the diagnosis of occlusal caries
Authors: Skodje F , Espelid I , Kvile K , Tveit A B
Published: October 2024

OBJECTIVES

To assess the impact of variations in radiographic density on occlusal caries diagnosis and observers' diagnostic strategy.

METHODS

Three series of radiographs of 60 extracted molars were examined by nine dental students and caries diagnosed using a five point confidence-rating scale. Film density in each series was varied by varying exposure time: 1 s (high density), 0.4 s (medium density) and 0.067 s (low density). The 'true' diagnoses were obtained by stereomicroscopy. Diagnostic quality was measured with ROC analysis as Az.

RESULTS

The difference in Az, values between the low and medium density series was statistically significant. The sensitivity and the specificity values for students' diagnoses in outer third of dentine were 85% and 50% for the high density series, 76% and 56% for the medium density series and 42% and 77% for the light series.

CONCLUSIONS

Occlusal caries was diagnosed best from the darkest radiographs. Specificity was higher with light radiographs but sensitivity increased with density. Therefore underdiagnosis is more frequent with light radiographs, while overdiagnosis occurs more often with dark. The awareness of these effects could be an important guideline in adjusting the density of digital images.
Chondrosarcoma of the maxilla: panoramic radiographic and computed tomographic with multiplanar reconstruction findings
Authors: Hayt M W , Becker L , Katz D S
Published: October 2024

Chondrosarcomas are extremely rare tumors of which approximately 10% are found in the maxillofacial region. In this report, we present the imaging findings of a maxillary chondrosarcoma on a panoramic radiograph of the jaws and computed tomography with multiplanar reconstructions. We recommend the latter as an excellent way to image evolving or suspected lesions of the maxilla, particularly for surgical treatment planning.
Bilateral bifid mandibular condyles. Report of four cases
Authors: Stefanou E P , Fanourakis I G , Vlastos K , Katerelou J
Published: October 2024

Four cases of bilateral bifid mandibular condyles are reported. A review of the literature showed that only four cases have been reported previously as incidental findings patients, while another four cases have been detected in post mortem material. Due to the minimal symptomatology, the diagnosis of a bifid condyle usually rests on radiological rather than clinical evidence.
Extraoral radiographic imaging of primary caries
Authors: Clifton T L , Tyndall D A , Ludlow J B
Published: October 2024

OBJECTIVE

To evaluate three extra-oral radiographic imaging modalities as alternatives to conventional intra-oral film for the detection of primary caries.

METHODS

Sixty-four extracted primary molar teeth with eighty-five carious lesions were radiographed using D-speed film (N = 8), panoramic imaging (N = 8), multidirectional tomography (N = 8), and linear tomography (N = 8). Eight trained observers were asked to identify the presence or absence of caries on each surface using a five point scale. Ground sections were viewed microscopically to determine truth. ROC curve areas (Az) were generated from observer responses and assessed with ANOVA.

RESULTS

Average of Az for the detection of combined results for proximal and occlusal lesions were 0.70 for D-speed, film, 0.58 for linear tomography, 0.64 for both multidirectional tomography, and panoramic film. Turkey's pairwise comparisons of Az revealed that D-speed film was significantly better than linear tomography (P = 0.0039). When data were divided into proximal and occlusal surfaces the variability due to modality remained significant (P = 0.0003 and P = 0.0024 respectively). Turkey's comparisons for proximal surfaces revealed that D-speed film was significantly better than linear tomography (P = 0.0007), multidirectional tomography (P = 0.0010) and panoramic radiography (P = 0.0100). For detection of occlusal lesions, multidirectional tomography was significantly better than linear tomography (P = 0.0075) and panoramic radiography (P = 0.0034), but not significantly different from D-speed film (P = 0.2337).

CONCLUSIONS

Multidirectional tomography and panoramic radiography performed as well as intra-oral D-speed film for the combined assessment of proximal and occlusal caries in the model used. when proximal surfaces were evaluated alone, D-speed film was significantly better. For occlusal caries there was no statistically significant difference between multidirectional tomography and D-speed film.
Evaluation of a new radiographic technique: diagnostic accuracy for mandibular third molars
Authors: Wenzel A , Aagaard E , Sindet-Pedersen S
Published: October 2024

OBJECTIVE

To compare the accuracy of Scanora with that of traditional panoramic and intra-oral radiography for the assessment of impacted mandibular third molars.

METHODS

Two hundred and fifty-four patients referred for removal of impacted or partly erupted third molars were randomly allocated to one of two groups; 133 were examined by the Scanora system and 121 by a panoramic plus a series of three intra-oral radiographs. The radiographs were read by a trained oral radiologist and her diagnoses validated against the surgeons' findings at operation.

RESULTS

There was agreement about the state of tooth eruption in 71.4% of Scanora and 74.4% of conventional examinations and about tooth position in 77.2 and 69.7% respectively (P < 0.05). The number of roots was assessed more accurately by Scanora (82.7% agreement) than by conventional (71% agreement) examination (P < 0.05). There was agreement about the root morphology in 70.4% of Scanora and 62.4% of conventional examinations. In 12% of the patients, the roots were in very close contact with the canal determined by the surgeon. In approximately 50% of these cases, the close contact to the canal was found by radiography with no significant differences between the methods.

CONCLUSION

The Scanora method was more accurate when validated against the surgeons' findings for the position and number of roots of ectopic mandibular third molars while both methods were equally accurate in demonstrating the relation between the roots and the inferior alveolar nerve.
A study of condylar movement by bilateral simultaneous videofluorography
Authors: Zhang X N , Nishiyama H , Murakami S , Fuchihata H
Published: October 2024

OBJECTIVES

To analyse the condylar movements of patients with temporomandibular disorders and investigate the mutual interaction between both temporomandibular joints (TMJs) by comparing bilateral simultaneous videofluorography with the disk position on MRI.

METHODS

Fifty-two patients who had been diagnosed as having internal derangement in one or both TMJs on the base of the clinical symptoms underwent bilateral simultaneous videofluorography and MRI. The TMJs were classified from the MRI into three categories: superior disk position (SDP), reducing disk displacement (RDD) and nonreducing disk displacement (NDD). Condylar movements of the TMJs were analysed from the videofluorography and correlated with the MR diagnoses.

RESULTS

The range of condylar movement of NDD joints was significantly shorter than that of SDP or RDD joints at maximum mouth opening (P < 0.001), but not at maximum protrusion and lateral protrusion. Based on the sagittal condylar path during maximum mouth opening and closing, three patterns of condylar movement were identified: normal, deflected and short. Sixty-nine per cent of the normal pattern were SDP, 55% of the deflected RDD and 77% of the short NDD. The condylar movement of a NDD or RDD joint could influence the range and pattern of movement of the contralateral joint.

CONCLUSIONS

Analysis of condylar movement was helpful in assessing the state of the disk because they were closely related. The range and pattern of condylar movement of both TMJs were mutually interrelated. Patients with signs and symptoms of internal derangement should have both sides examined for an accurate and complete diagnosis.
A radiographic method for measuring radiation dose based on beam quality
Authors: Syriopoulos K , Velders X L , Geraets W G , van der Stelt P F
Published: October 2024

OBJECTIVES

To develop a radiographic method for measuring radiation dose based on beam quality for inexpensive postal surveys of general dental practitioners.

METHODS

Different beam qualities were simulated to expose a commercially available film (X-Omat MA 18 x 22.4 cm, Ready Pack, Kodak Pathe, Paris, France). Density and contrast curves were fitted by means of 4th-degree polynomial functions. The curves were used to estimate beam quality (as the first HVL) and radiation dose in air for 22 different dental X-ray machines by means of linear interpolation. These estimations were compared with the measurements obtained with the NERO system and an ionization chamber (paired t-test).

RESULTS

No significant differences were found between the radiographic and the conventional methods in determining beam quality and radiation dose.

CONCLUSIONS

The radiographic method can be used to determine beam quality and radiation dose of dental X-ray machines from a single exposure. The radiographic method is simple and inexpensive and causes a minimum of disruption to the dental practice.
Mail survey of dental radiographic techniques and radiation doses in Greece
Authors: Syriopoulos K , Velders X L , van der Stelt P F , van Ginkel F C , Tsiklakis K
Published: October 2024

OBJECTIVES

To measure the entrance dose from periapical radiography in Greece and to determine the relative influence of factors affecting it.

METHODS

Special packs, containing a questionnaire, a film (X-Omat MA 18 x 22.4 cm, Ready Pack, Kodak-Pathe, Paris, France) with an attached aluminium stepwedge and a pre-exposed Ektaspeed Plus (Kodak) film, were mailed to 550 randomly selected dental practitioners. The results were tested statistically using an Analysis of Variance (level P < 0.05).

RESULTS

Three hundred and sixty-four packs were returned: 311 were complete but in 53 the pre-exposed film had not been developed. The average HVL was 1.4 mm Al 51% of the units had pointed cones and 34% a beam diameter larger than 6 cm. 54% of the dentists used E-speed films. Eighty per cent of the films were inadequately processed. For the total group the average entrance dose was 6.9 mGy (range 0.6-36 mGy), and 6.3 mGy (range 0.6-35 mGy) for the completed packs (n = 311). The radiation dose for the completed packs was significantly influenced by HVL, film speed, length of cone and standard of processing.

CONCLUSIONS

HVL, film speed, length of cone and standards of processing influence the entrance dose. Not all of the available measures for reducing radiation dose are commonly practised in Greece. Continuing education programs can help to improve radiation safety for dental patients.
Thrombosed varix in the submandibular space
Authors: Ida M , Kurabayashi T , Tanaka A , Sasaki T , Kishi T , Hoshi K , Okada N
Published: October 2024

Thrombosed varix in the oral region often appears as a pigmented mass in the mucosa simulating a hemangiomatous lesion. It rarely occurs in the deeper orofacial region. We report a case of thrombosed varix in the submandibular space with symptoms of a tumor. The clinical symptoms and MRI and CT findings are discussed. The clinical symptoms were not characteristics. High signal intensity on CT (80 HU) and a concentric signal distribution on CT and MRI may suggest a thrombosed varix.
Sensitometric evaluation of four dental X-ray films using five processing solutions
Authors: Syriopoulos K , Velders X L , Sanderink G C H , van Ginkel F C , van der Stelt P F
Published: October 2024

OBJECTIVES

To compare the sensitometric properties of four dental films: Ektaspeed Plus and Ultra-speed (Kodak Eastman Co, Rochester, USA) and new and previous Dentus M2 (Agfa-Gevaert, Mortsel, Belgium) in five different processing solutions.

METHODS

Characteristic curves were constructed for four dental X-ray films using five different processing solutions. All films were processed manually in three sets of chemicals for manual processing: Agfa (Heraeus Kulzer, Dormagen, Germany), Kodak (Kodak-Pathé, Paris, France) and Demat (Viscopac, Athens, Greece) and two sets of chemicals for automatic processing: Dürr XR and Periomat (Dürr Dental, Bietigheim-Bissingen, Germany). Analysis of variance and regression analysis was performed to examine the factors significantly affecting film density.

RESULTS

The new Dentus M2 film had comparable gradient, higher speed and lower base-plus-fog than its predecessor. It had comparable speed with Ektaspeed Plus in chemicals for automatic processing. All films had a higher speed and lower gradient when processed in the chemicals for automatic processing. The highest film speed was achieved using Dürr XR chemicals.

CONCLUSIONS

The new Agfa Dentus M2 film is an E-speed film and can be considered an alternative to Ektaspeed Plus: both can be recommended for use in dental practice as they contribute to dose reduction.
Zygomatic air cell defect (ZACD). Prevalence and characteristics in a dental clinic outpatient population
Authors: Carter L C , Haller A D , Calamel A D , Pfaffenbach A C
Published: October 2024

OBJECTIVES

To determine the prevalence and characteristics of zygomatic air cell defect (ZACD) among a general dental clinic population.

METHODS

The panoramic radiographs of 2734 dental clinic outpatients were examined for the presence of ZACD. ZACD was defined as a nonexpansile, nondestructive cyst-like radiolucency in the zygomatic process of the temporal bone which appears similar to the mastoid air cells and which does not extend further anteriorly than the zygomaticotemporal suture.

RESULTS

ZACD was found in 40 patients (1.5%) with a mean age of 49.6 (s.d. 18.0) years. Twenty cases (50%) each occurred in males and females. Meta-analysis of three large case series comprising 4579 patients revealed a total of 76 cases of ZACD (1.7% prevalence) occurring over an age range of 15-83 years. Thirty-four (44.7%) occurred in males while 42 (55.3%) occurred in females. Bilateral ZACD were found in 17 patients (22.4%).

CONCLUSIONS

ZACD is not a rare anatomical variant, and clinicians planning eminectomy or other surgical procedures involving the zygomatic arch are advised to obtain appropriate presurgical imaging studies to avoid the need for creative intra-operative reconstruction.
Metallic residues as a source of artifacts in magnetic resonance imaging of the temporomandibular joint
Authors: Tetsumura A , Honda E , Sasaki T , Kino K
Published: October 2024

OBJECTIVES

To establish the source of metallic artifacts on postoperative MRI of the temporomandibular joint after arthroplasty.

METHODS

An experiment was carried out to evaluate MR artifacts which were thought to have been caused by minute metallic particles deposited at surgery. Four types of cutting instruments were used to cut an extracted tooth: a diamond bur attached to a dental air turbine handpiece, a steel bur and bone bur attached to a dental micromotor handpiece and a bone file. The tooth fragments were collected in plastic centrifuge tubes in water. These samples were evaluated with six MR sequences.

RESULTS

MR artifacts were clearly demonstrated in samples using the bone bur and the bone file but not the diamond and steel burs.

CONCLUSIONS

The artifacts seen on postoperative MRI were derived from minute metal particles from the bone bur or file used for condylar arthroplasty. Metal artifacts should be considered when interpreting postoperative MR images.
An audit of occipitomental radiographs
Authors: Logan G M , Brocklebank L M
Published: October 2024

OBJECTIVES

To audit the justification for and image quality of occipitomental (OM) radiographs obtained at a dental teaching hospital.

METHODS

One hundred OM radiographs taken at Glasgow Dental Hospital and their associated request forms were analysed by two examiners retrospectively. Information recorded from the request form included the age and gender of the patient, requesting department, grade of requesting clinician, reason for the request and exposure factors. The radiographs were assessed for radiographic density, patient positioning, presence of abnormality and whether the maxillary sinuses were normal or not. It was then decided by reference to the clinical records if there had been an indication for taking the radiograph.

RESULTS

The majority of the requests were from junior staff, most frequently for pain or sinusitis. Almost all were from the Departments of Oral Surgery, Oral Medicine or Dental Accident and Emergency (A&E). The technical quality of the radiographs was variable, especially with respect to superimposition of the petrous temporal bone. Over half of the cases had normal sinuses, no abnormality and no indication for the radiograph.

CONCLUSIONS

Many requests were inappropriate and the resultant radiographs had a low diagnostic yield. The technical quality of the radiographs was variable. Guidelines for clinicians for the prescription of OM radiographs were produced and the protocol for radiographic technique changed.
Fibrous dysplasia in the jaws of a Hong-Kong population: radiographic presentation and systematic review
Authors: MacDonald-Jankowski D
Published: October 2024

OBJECTIVE

To compare the radiographic presentation of fibrous dysplasia in the jaws of Hong Kong patients with the features reported in other populations.

METHODS

The clinical records and radiographs were reviewed of seven patients with fibrous dysplasia whose diagnosis had been histopathologically confirmed. Published series of fibrous dysplasia were subjected to systematic review.

RESULTS

The male:female ratio was 4:3: one woman was Indian in origin; the other six patients were ethnic Chinese. The females were on average older than the males. Three cases affected the mandible and four the maxilla. Five cases affected the right side and two the left. A swelling was the principle clinical manifestation. The lesions were generally large, affecting most or all of the hemimandible or hemimaxilla involved. All cases exhibited expansion and had ground glass opacification. The four cases affecting the maxilla reduced the lumen of the maxillary antrum. The systematic review was carried out on 104 individual cases derived from nine reports of which only 93 cases were accompanied by radiological details. Many of the reports were limited in their scope, particularly with regards to radiological features. Fibrous dysplasia is more frequent in the maxilla in Oriental populations. Swelling is the most frequent clinical finding and buccolinqual expansion the most frequent radiological finding.

CONCLUSION

The pattern of presentation of fibrous dysplasia in a Hong Kong population is broadly in agreement with reports from other populations.
The effects of sustained incisal clenching on the temporomandibular joint space
Authors: Takenami Y , Kuboki T , Acero C O , Maekawa K , Yamashita A , Azuma Y
Published: October 2024

OBJECTIVE

To determine the effect of sustained incisal clenching on the width of the temporomandibular joint space.

METHODS

Nine normal subjects clenched on an anterior appliance for 10 min at 49 N. Sagittal tomograms were obtained during comfortable closure in the intercuspal position (ICP) (ICP-Before), comfortable closure on bite force transducer without clenching (BFT-Before), start of clenching (BFT-0), end of 5 min clenching (BFT-5), end of 10 min clenching (BFT-10), comfortable closure on the bite force transducer immediately after clenching (BFT-After) and comfortable closure in ICP after clenching (ICP-After). Joint space dimensions were automatically measured by a computerized image analysis system.

RESULTS

The minimum joint space dimension was significantly reduced at BFT-5 (P = 0.0381), BFT-10 (P = 0.0019) and BFT-After (P = 0.0053) in relation to BFT-Before. The condylar position was also significantly shifted upward at BFT-0 (P = 0.0422), BFT-5 (P = 0.0005), BFT-10 (P = 0.0001), and BFT-After (P = 0.0004) in relation to BFT-Before.

CONCLUSION

Sustained incisal clenching at 49 N causes significant anterior joint space reduction. We believe this is due to marked compression of the articular cartilage and disc.
Cross-sectional presurgical implant imaging using tuned aperture computed tomography (TACT).
Authors: Liang H , Tyndall D A , Ludlow J B , Lang L A
Published: October 2024

OBJECTIVES

To investigate tuned aperture computed tomography (TACT) as an alternative to conventional tomography for cross-sectional imaging of potential implant sites.

METHODS

Twenty potential implant sites in three dry human mandibles were selected. Sixteen TACT basis projections were recorded on film using a linear array of source positions. Films were scanned and 20 TACT and iterative TACT slices were reconstructed using TACT Workbench software. Maximum height and width were measured on one representative slice of each site. Results were compared with the ground truth using ANOVA and Wilcoxon signed rank tests.

RESULTS

The means of relative difference in maximum height were 1.55 and 1.56% for TACT and iterative TACT respectively (P = 0.8643). The means of relative difference in width were 5.96 and 6.36% for TACT and iterative TACT respectively (P = 0.4845). More than 75% measurements were within +/- 1 mm of ground truth for both modalities.

CONCLUSIONS

TACT may provide an alternative to conventional tomography for dental implant imaging. Further investigations should be performed to explore factors affecting image quality.
Bone formation in a carcinoma of the maxillary antrum
Authors: Lee K , Suei Y , Yamada T , Masuda S , Ogawa I , Tanimoto K
Published: October 2024

Malignant tumors of the paranasal sinuses are rare: about 80% are found in the maxillary sinus123. The presence of dense radiopaque masses in combination with destruction of the bone margins suggests osteosarcoma or aspergillosis4 rather than carcinoma. We present a unique mucoepidermoid carcinoma of the maxillary antrum containing new bone formation and discuss the differential diagnosis.
Diagnostic imaging of pigmented villonodular synovitis of the temporomandibular joint associated with condylar expansion
Authors: Song M Y , Heo M S , Lee S S , Choi S C , Park T W , Lim C Y , Lim J J
Published: October 2024

Pigmented villonodular synovitis (PVNS) is a rare lesion of the temporomandibular joint. We report a case which was initially misdiagnosed as a parotid tumor. CT revealed a well-defined mass demonstrating higher attenuation than the adjacent soft tissue with marked expansion of the mandibular condyle. MRI clearly delineated the extent of the lesion which had very low signal intensity on both T1W and T2W sequences due to the effect of hemosiderin. The usefulness of these imaging procedures in diagnosis of PVNS is discussed.
Accuracy of implant treatment planning utilizing template-guided reformatted computed tomography
Authors: Besimo C E , Lambrecht J T , Guindy J S
Published: October 2024

OBJECTIVES

To evaluate the magnitude of error in transferring the planned position of implants from reformatted CT scans to a surgical template.

METHODS

The deviation between the position of the apex of the proposed implant in paraxial CT reformats and on the corresponding study cast was measured in 77 prospective sites in five maxillas and nine mandibles.

RESULTS

The transfer error was 0.6 (s.d. 0.4) mm in the maxilla and 0.3 (s.d. 0.4) mm in the mandible.

CONCLUSIONS

The transfer errors detected in this investigation are not clinically relevant. Other factors involved in transferring positional and angular measurements from reformatted CT to the surgical site may result in more significant errors.
Physical properties of a photostimulable phosphor system for intra-oral radiography
Authors: Stamatakis H C , Welander U , McDavid W D
Published: October 2024

OBJECTIVES

To determine physical properties of the Digora digital intra-oral radiographic system (Soredex Orion Corporation, Helsinki, Finland) for different calibration settings and beam energies.

METHODS

The line spread function (LSF) and the modulation transfer function (MTF) were determined from radiographs of a slit. Noise power spectra (NPS) were determined from radiographs exposed to homogeneous radiation fields at 10, 50 and 100% of the calibration exposure for three tube potentials. All calculations were performed using relative values of exposure comprised of gray level, the signal at the photomultiplier tube and the amplified signal in order to confirm agreement between these different approaches. Noise equivalent quanta (NEQ) were calculated from the one-dimensional NPSs and the MTF. Detective quantum efficiencies (DQE) were determined from the NEQs and representative values of the photon fluence. Signal-to-noise ratios (SNR) were calculated for different signal contrasts applying the NEQs.

RESULTS

The MTF of the system exhibited typical characteristics and falls to a value close to zero at the Nyquist frequency of about 7 cycles/mm. Noise as expressed by the NPS was found to be relatively low, i.e. about 10(-5) to 10(-6) mm2 depending on exposure and frequency. There was no significant difference between data obtained at different beam energies. The NEQ and hence the DQE were relatively high. DQE decreased with increased exposure. For exposures in the clinical range of the DQE reached a peak value of about 25%. SNRs are favorable.

CONCLUSION

The physical properties of the Digora intra-oral system indicate that it is suitable for digital intra-oral radiography.
Dental optical coherence tomography: a comparison of two in vitro systems
Authors: Otis L L , Colston B W , Everett M J , Nathel H
Published: October 2024

OBJECTIVE

To compare the imaging results obtained with two different in vitro prototype dental optical coherence tomography (OCT) systems.

METHODS

Two prototypes were evaluated: an 850 nm wavelength, 700 microW OCT system with a relatively low numerical aperture (0.03) and a 1310 nm wavelength, 140 microW system with a higher numerical aperture (0.20).

RESULTS

Using the 850 nm system a characteristic scattering signal was observed that correlated with the depth of a periodontal probe. There was, however, insufficient light penetration to create images with adequate resolution. Improved image quality was achieved with the 1310 nm OCT system; these images had sufficient resolution to allow identification of anatomical structures important for the diagnostic assessment of oral structures.

CONCLUSIONS

These results illustrate the improvement in imaging dental structures that can be obtained with a prototype 1310 nm OCT system. The feasibility of OCT as a dental imaging technique is verified.