Cone Research Articles

Review: deformation and optimisation crashworthiness method for foam filled structures

Abstract In this paper, we give overview of deformation modes for the uniform foam filled thin-walled structure such as circular tubes, square tubes, rectangular tubes, tapered tubes, hat tubes and cone tubes. Foam material is used as a reinforcing material on a thin wall tube which has potential as being a good energy absorber. This is evident from many of the studies undertaken on the crashworthiness performance and energy ab-sorption of the thin wall tube. Also, this paper presents a review of the current state of the art in computa-tional optimization methods applied to foam filled structures, offering a clear vision of the latest research advances in this field.

An Experimental Slope Method for a More Accurate Measurement of Relative Radiation Doses using Radiographic and Radiochromic Films and Its Application to Megavoltage Small-Field Dosimetry.

Purpose:An experimental method using the linear portion of the relative film dose–response curve for radiographic and radiochromic films is presented, which can be used to determine the relative depth doses in a variety of very small, medium, and large radiation fields and relative output factors (ROFs) for small fields.Materials and Methods:The film slope (FS) method was successfully applied to obtain the percentage depth doses (PDDs) for external beams of photon and electrons from a Synergy linear accelerator (Elekta AB, Stockholm, Sweden) under reference conditions of 10 cm × 10 cm for photon beam and nominal 10 cm × 10 cm size applicator for electron beam. For small-field dosimetry, the FS method was applied to EDR2 films (Carestream Health, Rochester, NY) for 6 MV photon beam from a linac (Elekta AB, Stockholm, Sweden) and small, circular radiosurgery cones (Elekta AB, Stockholm, Sweden) with diameters of 5, 7.5, 10, 12.5, and 15 mm. The ROFs for all these cones and central axis PDDs for 5, 10, and 15 mm diameter cones were determined at source-to-surface distance of 100 cm. The ROFs for small fields of CyberKnife system were determined using this technique with Gafchromic EBT3 film (Ashland, NJ, USA). The PDDs and ROFs were compared with ion chamber (IC) and Monte Carlo (MC) simulated values.Results:The maximum percentage deviation of PDDFS with PDDIC for 4, 6, and 15 MV photon beams was within 1.9%, 2.5%, and 1.4%, respectively, up to 20-cm depth. The maximum percentage deviation of PDDFS with PDDIC for electron beams was within 3% for energy range studied of 8–15 MeV. The gamma passing rates of PDDFS with PDDIC were above 96.5% with maximum gamma value of >2, occurring at the zero depths for 4, 6, and 15 MV photons. For electron beams, the gamma passing rates between PDDFS with PDDIC were above 97.7% with a maximum gamma value of 0.9, 1.3, and 0.7 occurring at the zero depth for 8, 12, and 15 MeV. For small field of 5-mm cone, the ROFFS was 0.665 ± 0.021 as compared to 0.674 by MC method. The maximum percentage deviation between PDDFS and PDDMC was 3% for 5 mm and 10 mm and 2% for 15 mm cones with 1D gamma passing rates, respectively, of 95.5%, 96%, and 98%. For CyberKnife system, the ROFFS using EBT3 film and MC published values agrees within 0.2% for for 5 mm cone.Conclusions:The authors have developed a novel and more accurate method for the relative dosimetry of photon and electron beams. This offers a unique method to determine PDD and ROF with a high spatial resolution in fields of steep dose gradient, especially in small fields.

Modeling of Oxidation Process of Coal Tar Pitch in Rotating Kilns

In this paper, a three‐dimensional numerical model has been developed to study the process of oxidative weight increment of coal tar pitch in a rotating kiln. Based on the two‐fluid method, the gas phase is modeled by realizable k‐ε turbulent model and the solid phase is modeled by kinetic theory of granular flow. The dense gas‐solid flow, heat transfer, and oxidation reaction for the bed and freeboard regions are simultaneously solved. The model is applied to a rotating kiln with a cylinder of 0.75 m length and 0.4 m diameter in the front and circular truncated cone on exit side. The detailed verification of model is firstly performed by comparisons with the available experimental data. The particle velocity profiles, product gas compositions, and various forms of solid motion in rotary kilns are contrastively analyzed. Afterwards, simulations are carried out to obtain the primary hydrodynamic and reactive characteristics in the rotary kiln. At the steady state, the particle velocity peak is located at the active layer surface, while the velocity has the opposite direction in the passive layer. The bed region generally has a higher temperature than the freeboard due to the large thermal capacity. The concentrations of product gas compositions, such as CO2, CO, and CH4, and solid product of oxidation, increase sharply near the surface and then keep on the steady values inside the bed. The effects of rotational speed of the rotary kiln and flow rate of air are also studied. The increasing rotational speed significantly accelerates the particle movement of the active layer and raises the final oxidative yield of coal pitch spheres. By contrast, increasing the flow rate of air has little effect on the particle motion and oxidation yield of coal pitch.

Hypersonic boundary-layer separation detection with pressure-sensitive paint for a cone at high angle of attack

A measurement technique for identifying lee-side crossflow-induced boundary-layer separation on a blunt $$7^{\circ }$$ half-angle circular cone at high angle of attack has been developed and tested. Previous work has shown that local minima in root-mean-squared (rms) pressure fluctuations on the surface are good identifiers of separation. These surface pressure fluctuations are measured with a temperature-corrected, high-frequency-response anodized-aluminum pressure-sensitive paint (AA-PSP). This AA-PSP was made in-house to provide the high frequency response required for this work. The sensor’s frequency response of 3 kHz proved to be fast enough to detect lines of local minimum rms pressure fluctuations indicative of separation on the lee side of the cone for angles of attack from $$9.8^{\circ }$$ to $$15.8^{\circ }$$ . A shift in the separation location towards the windward side of the model was observed as angle of attack increased; however, the separation location converged to a constant azimuth for angles of attack greater than or equal to $$1.8\times$$ the cone’s half angle.

Improving the management system for the distribution of materials in a blast furnace using a conical charging device

В статье рассмотрена задача организации автоматической подачи материалов в доменную печь при необходимости обеспечить требуемую схему распределения материалов по радиусу, а также устранить перепады уровней между секторами. Рассмотрены особенности радарных уровнемеров. Показано, что существующие схемы установки датчиков уровня не ориентированы на контроль распределения материалов по радиусу печи. Предложен алгоритм управления, обеспечивающий реализацию программы распределения материалов по радиусу и компенсацию неравномерности уровней по секторам в едином цикле выгрузки материалов.

Evaluation of Cone of Uncertainty in Tropical Cyclone Track Forecast Over North Indian Ocean Issued by India Meteorological Department

ABSTRACT India Meteorological Department (IMD) introduced cone of uncertainty (COU) in cyclonic disturbances (CDs) alongwith the 72 hr track forecast over the north India Ocean (NIO) in 2009. The track forecast for CDs is issued for + 6, + 12, + 18, + 24, + 36, + 48, + 60 and + 72 hrs time period from the stage of deep depression onwards. An attempt is made to evaluate COU forecast issued by IMD during 2009-2011(3 years). The size of the cone is deduced from climatological track forecast errors. The accuracy of COU forecast has been analysed with respect to basin of formation, season of formation, intensity and type of track (climatological/straight moving and recurving/looping type) of CDs by calculating percentage of total number of forecasts in each category lying within COU. The observed track lies within the forecast COU in about 60% of the cases over the NIO. The accuracy of COU forecast is about 66% in post-monsoon season and about 50% in pre-monsoon season. The observed track lies within the forecast COU in 90% cases of climatological/straight moving CDs and 39% cases of recurving/ looping CDs. The observed track lies within COU forecast in about 71% cases of severe cyclonic storm and 37% cases of cyclonic storm/deep depression.

Tropical Cyclone Forecast Verification by India Meteorological Department for North Indian Ocean: a Review

ABSTRACT The tropical cyclone (TC) forecast verification procedure followed by India Meteorological Department (IMD) is reviewed herewith as compared to the standard prescribed by World Meteorological Organisation. The limitations in the present procedure and the future scope are presented and analysed. The IMD has considerably increased its efforts in recent years in the areas of TC forecasting and verification. Many facilities have been developed to enable a detailed assessment of the global model’s performance in the forecasting of TCs as well as operational TC forecast performance. Further development of these facilities is being undertaken by IMD. There are grey areas in TC forecast verification of IMD in the field of calculation of forecast error in surface wind radii in geographical quadrants, which is yet to start. Also there is need for improvement in verification of storm surge, wave height, coastal inundation forecasts and heavy rainfall forecasts by calculating the skill parameters and also by improving the analysis data required for verification of forecasts. Similarly there is need for verification of strike probability as well as dynamical cone of uncertainty as given by ensemble prediction system.

A Robust Model to Test the Accuracy of Cone Beam Computed Tomography Linear Measurements

In planning for placement of dental implants in edentulous mandibles, the accuracy of the linear measurements of the cone beam computed tomography (CBCT) has been questioned. This study used a digital caliper as the gold standard to which linear measurements taken from CBCT were compared. Customized aluminum screws, 2.8 mm in diameter and 11-12 mm in length, were used as dental implant analogues in the canine, premolar, and molar regions in completely edentulous synthetic polyurethane mandibles. A 2 mm aluminum wire was used as the mandibular canal. A total of 240 readings by the digital caliper and the CBCT were recorded for the screws length and diameter, mandibular canal wire diameter, and the distance from the apices of the screws to the superior border of the mandibular canal wire. The statistical analysis was performed using the paired sample T test, with a p value of .05 considered statistically significant. Statistically significant differences between the digital caliper readings and those of the CBCT were recorded in the canine, premolar and molar regions where all the over-and under-estimations did not exceed half a millimeter. The statistically significant discrepancies found in the linear measurements of the CBCT were less than 1 mm, and therefore did not exclude the CBCT from being a beneficial tool in the planning for dental implant placement. However, it is important to note that the results of this study and cannot be generalized to all CBCT machines as they are not created equal by different manufacturers.

Artifact reduction techniques in Cone Beam Computed Tomography (CBCT) imaging modality

Introduction: Cone beam computed tomography (CBCT) was introduced and became more common based on its low cost, fast image procedure rate and low radiation dose compared to CT. This imaging modality improved diagnostic and treatment-planning procedures by providing three-dimensional information with greatly reduced level of radiation dose compared to 2D dental imaging modalities for investigation of maxillofacial skeleton, dentition and the relationship of anatomical structures. However, CBCT is associated with multiple artifacts like. Extinction artifacts, beam hardening artifacts, partial volume effect, aliasing artifacts, ring artifacts and motion artifacts (misalignment artifacts), Noise and scatter. All of them leads to image quality reduction and have capability of Mistakenly considering as a pathological lesion. This study aimed to investigate Cone Beam Computed Tomography artifacts and their reduction procedures. Materials and Methods: A systematic search of the literature published from 2000 to 2017 in the PubMed, scopus and web of science databases was performed. The following key words combined in different ways: cone beam computed tomography, CBCT Artifacts and artifact reduction. Results: Artifact is caused by several factors containing reconstruction parameters like small field of views (FOVs), presence of metal objects, patient movement, etc. Artifact reduction methods can have divided into two categorize preprocessing in the projection domain and post processing in the image domain. Limitation of field of view, modification of patient head position or separating dental arches for scatter reduction, Application of high KVP in order to beam hardening reduction, iterative method and projection modification method for metal artifacts are recommended. In addition, Filtration, interpolation, iterative reconstruction and filtering algorithms, application of the smaller voxel size and respiratory gating are other suggested items for artifact reduction in CBCT. Conclusion: Multiple artifacts accompany CBCT imaging procedures. There for With the aim of improving the quality of the CBCT images; reducing the artifact caused scatter photons , various software-based and hardware-based correction methods are recommended .

Evaluation of Three-dimensional Treatment Planning System (TPS) performance in dose calculation of virtual wedged fields using film dosimetry

Introduction: Nowadays radiotherapy plays an important role in cancer treatment. Different radiotherapy techniques improvement emphasizes on using of the precise ، appropriate and useful algorithms. one of these techniques are wedged which is used in radiotherapy to compensate missing tissues and create a uniform dose distribution in tissues. The Siemens Artiste linear accelerator supports a virtual wedge ، that this wedge creates a dose distribution similar to a physical wedge without the use of any extra accessory and wedged profiles are produced moving collimator jaw during irradiation with a constant speed but varying the dose rate. In this study ، TPS performance is evaluated in virtual wedged fields by comparing the calculated and measured results. Materials and Methods: The calculations were performed by the collapsed cone superposition algorithm based TPS for two tangent fields in anthropomorphic slab phantom using 15، 30، 45، 60 virtual wedges for field size of 20 × 20 cm2 for 6 and 15 MV photon beams. Measurements were produced by Gafchromic EBT films and reading exposed films with scanner. Results: Good agreement between the measured dose with film dosimetry and calculated dose with collapsed cone superposition algorithm based TPS with using virtual wedge in heterogeneous environment and different energies were found ، with the maximum difference not exceed 3 -5%. The increase in wedge angle due to increase in the difference between calculated and measured data. Conclusion: : The results from this study showed that the accuracy of collapsed cone superposition algorithm based TPS used with the virtual wedges for two tangent fields is enough for the clinical usage under the studied experimental conditions.

Comparative Study between Electronic Portal Imaging Device (EPID) and Cone Beam Computed Tomography (CBCT) for Radiation Treatment Verifications

Introduction: Electronic Portal Imaging Device (EPID) and Cone Beam Computed Tomography (CBCT) are the preferred tools of Image Guided Radiotherapy (IGRT) and Dose Guided Radiotherapy (DGRT) which have been used for Radiotherapy treatment verifications. As a result, the number of publications dealing with these two tools for radiation treatment verification has increased considerably over the past years. This paper aims to compare and contrast the overall differences and similarities of EPID and CBCT tools based on their set-up verification accuracy, dosimetric verification accuracy, calibration and quality control methods, image quality, dose measurement, calculation, and evaluation methods for radiation treatment verifications. Materials and Methods: The relevant articles published in English were searched based on the keywords of EPID and CBCT for radiation treatment verifications using PubMed, EMBASE, Scopus, and Web of Science databases and finally exported to EndNote for screening, downloading, and reference management processes. Results: A total of 2512 articles were searched and subsequently screened by removing duplications and reading title and abstract to identify original articles that directly related with radiation treatment verifications using EPID and CBCT for different cases. This yielded 226 relevant articles. After downloaded and read full articles, only compared results between EPID and CBCT treatment verifications were selected. This yielded, a final total of 23 articles to be included for this work. Conclusion: EPID and MV-CBCT have almost equal potential to indicate the set-up error but since they used the LINAC’s energy, no cross-calibration procedure is needed because the imaging geometry is the same as the treatment geometry though both of them have poor image quality. The image quality of KV-CBCT is superior to both EPID and MV-CBCT and is better to indicate the set-up error. CBCT in conjunction with energy fluence maps from EPID could be used to verify the dose delivered. In this instance, a cross-calibration between the KV CBCT and EPID would be required which would not be necessary with MV CBCT. Though MV CBCT handles inhomogeneity better, soft tissue visualization is superior with KV CBCT. EPID is used to calibrate the LINAC machine. Generally, both EPID and CBCT have their own different advantages and need further study to solve their limitations.

Mega Voltage Cone Beam Computed Tomography (MV- CBCT) using a Standard Medical Linear Accelerator and EPID: A feasibility study.

Introduction: The success of radiotherapy cancer treatment delivery depends on the accuracy of patient positioning for each treatment session. A number of kilovoltage x-ray volumetric imaging modalities with an additional source and detector have been developed to allow patient set-up verification based on the internal anatomy, but a significant portion of medical linacs are only equipped with electronics portal imaging device (EPID) as a planar imaging system. The aim of this study is investigating the feasibility of megavoltage cone beam computed tomography (MV-CBCT) using medical linac and EPID to obtain volumetric data for 3D representation of patient in treatment position. Materials and Methods: The MV-CBCT system consists of an amorphous silicon EPID with an active area of 41×41 cm2 attached to an Elekta Precise linac. Initially, the quality control tests were performed to evaluate the safety features, mechanical stability and quality of the megavoltage imaging system. The MV-CBCT scanning protocol was divided into three major parts. In the first part, Step and Shoot delivery mode was used to acquire projections of an anthropomorphic head phantom and quality assurance phantom in increments of 30 with 3 MU and x-rays of 6 MV energy over 3600 of gantry rotation. Afterwards, noise reduction was conducted by applying 2D adaptive wiener filter to projections. Furthermore, it is found that scatter produces cupping artifacts and increase uniformity variations across the reconstructed tomograms. Therefore, a scatter correction method which is based on a superposition of Monte Carlo generated scatter kernels was applied to the portal images. In the latest part of the research, the Feldkamp cone-beam algorithm used to reconstruct the 2D portal images to a 3D image, then, image quality characteristics such as; uniformity, contrast-to-noise ratio (CNR) and spatial resolution were investigated using the Gammex phantom Results: The safety interlocks were found to be functional. The EPID response uniformity was within 97% across the detector. Contrast resolution of the MV imaging system was found to agree with the recommended tolerance; and the value of f50 for spatial resolution was 0.41lp/mm for 6 MV. The supporting arm deviation was within ±1 mm, and corrections are required to realign the projections. Reconstructed slices from the spatial and contrast resolution modules of the Gammex phantom shown that the 4 lp/cm section was clearly resolvable, and also bone, air, polyethylene, and acrylic inserts can be clearly resolved, with bone and air having the greatest and polyethylene having the lowest contrast, which improved after scatter correction. Furthermore, the maximum uniformity variation was determined of 15.75%-pixel intensity units which reduced significantly after scatter correction. Conclusion: The result of this study has demonstrated that EPID can be used to acquire volumetric images with high enough quality to improve patient alignment prior to dose delivery.

Dosimetric Evaluation of Dose calculation algorithms of Monaco Treatment Planning System in the heterogeneities area

Introduction: In radiation therapy, the accuracy of dose calculations by a treatment planning system (TPS) is important to achieve tumor control and to spare normal tissue. Treatment planning system calculations in the heterogeneous situation may present significant inaccuracies. In this study, three different dose calculation algorithms, pencil beam (PB), collapsed cone (CC), and Monte-Carlo (MC), provided by our planning system were compared to assess their impact on the three-dimensional planning of lung region. Materials and Methods: The methodology was based on IAEA TEC-DOC 1583. The phantom resembling the human thorax are used and all tests were planned on three- dimensional treatment planning systems (TPSs) and irradiated with photon beams of 6, and 18 MV X-ray energies. The doses in specific points were measured with an ionization chamber. The differences between the measured and calculated doses were reported. This study was tested using different algorithms/inhomogeneity correction methods implemented in Monaco treatment planning system. Results: The measurements were conducted for all test case datasets for two photon beam energies and calculation algorithms. The deviation between the measured and calculated values for all test cases made with advanced algorithms (MC and CC) were within the agreement criteria, while the larger deviations were observed for PB algorithm. Subsequently, there were discovered dose differences greater than 20% for some simple algorithms and high energy X-ray beams. The number of measurements with results outside the agreement criteria increased with the increase of the beam energy and decreased with TPS calculation algorithm sophistication. Also, a few errors in the basic dosimetry data in TPS were detected and corrected. Conclusion: Differences were found when comparing the calculation algorithms. The PB algorithm actually overestimated the dose compared with those calculated by the CC and MC algorithms. The MC algorithm showed better accuracy than the other algorithms. Therefore advanced dose calculation algorithms are suitable and should be used in clinical practice

Comparison of radiotherapy techniques to reduce hematologic toxicity in whole pelvic radiation therapy

Introduction: Concurrent chemoradiotherapy (CRT) is a standard treatment method for patients with carcinoma of cervix. Despite admirable therapeutic results, acute hematologic toxicity (HT) is common with this regimen. Many studies evaluate the relationship between the bone marrow dosimetric parameters and the severity of HT and result shown that the low dose of bone marrow would decrease the incidence of HT in patient undergoing concomitant CRT. In this study the dosimetric parameters of two radiotherapy plans in managing of cervix cancer has been evaluated to investigate the best plan on the way of reducing bone marrow dose. Materials and Methods: Computed tomography scans of 18 patients with carcinoma of cervix were acquired and transferred to the 3D treatment planning system. The corePlan3D treatment planning system was used to contour all of the structures and to compute the dose distribution for plans based on collapsed cone convolution (CCC). For each patient, two different treatment plan were prepared using 15 MV photon energies. The minimum dose (Dmin), maximum dose (Dmax) and mean dose (Dmean) to target (PTV) and femoral head were compared for each plan. Results: Result shown that our manipulated four-field plan which use anterior oblique beams seemed to deliver a lower mean dose to femoral head against conventional box fields (Dmean=66.7±3.1 cGy, 98.8±7.3 cGy, Dmax=117.5±3.0 cGy, 126.9±4.3 cGy, respectively) and deliver sufficient dose to PTV (Dmax=213.5±4.2 cGy, 194.6±2.0 cGy, respectively). Conclusion: With suspicious planning in respect to choice of beam angles, beam weighting, and appreciation of potential exposure of normal tissues to exit dose, this study revealed that compared with conventional box fields, anterior oblique beams can achieve significant reductions in the dose to BM with adequate dose coverage to the PTV with an accurate beam arrangement

Comparison of two different methods for CTDIw calculation in CBCT systems

Introduction: Dental Cone beam CT (CBCT) is an imaging modality which has emerged as a 3D imaging modality of choice for osseous structures in the maxillofacial region. With increased usage of CBCT imaging for diagnosis and treatment planning, it is imperative that stringent dose assessments must be performed for dose estimation to safeguard both the patients and operating staff. In CT scanners, CT dose index (CTDI) measurements are part of standardized quality assurance protocols that uses a 10-cm pencil ionization chamber to approximate dose output for a single axial scan. The weighted CTDI (CTDIw = 1 CTDIc + 2 CTDIp) is used for 3 3 CTDI calculations. The SEDENTEXCT project introduces a type of dose index calculation method for dental CBCT systems, that is calculating the dose measurements from the central and the peripheral positions to represent a dose index (Sedentex-DI2). In this study we utilize the same method to calculate CTDIw that is used in CT scanners and compare with the Sedentex-DI2 method as shown in: D =Dc+Dp to provide insights for developing a robust dose periphery 2 assessment in dental CBCT systems. Materials and Methods: The CTDI head phantom of PMMA with a diameter of 16 cm and 15 cm long and 10-cm cylindrical pencil-shaped air ionization chamber for CTDI measurements were used in this study. Two different CBCT machines scanned the phantom: CS9300 (Carestream Health, New York, NY), ProMax 3D mid (Planmeca Oy, Helsinki, Finland) and three FOVs was used in both of them. Scans in both of the systems were repeated another two times at the same exposure parameters to check the reproducibility of the measured dose. All dose measurements at off- axis FOVs were performed. Results: The CTDIw from SEDENTEXCT (DI2) method was 3.1245 mGy, 3.2296 mGy and 1.5447 mGy for (o8×5, o20×10 and of o4×5 cm2 FOVs, respectively) in ProMax 3D mid system. In CS9300 system these measurements were 3.104 mGy, 3.942 mGy and 6.648 Gy for FOVs of (o5×5, o10×5 and o10×10 cm2, respectively). But calculated CTDIw by standard CTDI method was 2.923 mGy, 3.308 mGy and 1.763 mGy for (o8×5, o20×10 and o4×5 cm2 FOVs, respectively) in ProMax 3D mid system and in CS9300 system these measurements were 2.969 mGy, 3.794 mGy and 6.502 Gy for FOVs of (o5×5, o10×5 and o10×10 cm2, respectively). Conclusion: The results show that the calculated CTDIw values were very close to each other in both the standard and Sedentex-DI2 methods and did not differ significantly. So, it seems that both methods can be used to measure the dose index in CBCT systems. However, it should be noted that the dose values in the peripheral holes indicate that there is no symmetric distribution for the dose in these systems, and therefore CTDI measurement methods cannot be applied to all different FOVs at different central and off-axis positions. We should introduce a valid dose index based on the dose distribution in each mode of the FOV for each system.

V-shaped wings with the central body in supersonic flow

The results of a theoretical investigation of the flow pattern of V-shaped wings at supersonic flow velocities are presented. Data are presented on the flow structure near V-shaped wings with a central body in the form of a part of a circular cone within the framework of the ideal gas model. The applicability of the criteria for the existence of nonviscid vortex structures has been determined, but with differences due to the shape of the body. Influence of the central body on the aerodynamic quality of its layout with a V-shaped wing was studied. A significant dependence of geometry of the optimal body on the lift coefficient was established.

Extramandibular Presentation in the Course of the Inferior Alveolar Nerve: A Case Report and Review of the Literature

The inferior alveolar nerve (IAN) is a branch of the mandibular nerve, the third division of the trigeminal nerve (V cranial nerve). Its location and course into the mandible is very important because of its susceptibility to the injury during any surgical or prosthetic approaches. Cone beam computed tomography (CBCT) is a three-dimensional imaging modality, with less exposure than multi slice computed tomography (MSCT), being considered an ideal imaging tool for maxillofacial diagnosis. We present an unusual extramandibular submucosal course of IAN in relationship with a mandibular exostosis, and with no association with the sensory disorder. J Med Cases. 2018;9(12):403-405 doi: https://doi.org/10.14740/jmc3215

Nose-Tip Bluntness Effects on Transition at Hypersonic Speeds

The existing database of transition measurements in hypersonic ground facilities has established that as the nose-tip bluntness is increased the onset of boundary-layer transition over a circular cone at zero angle of attack shifts downstream. However, this trend is reversed at sufficiently large values of the nose-tip Reynolds number, so the transition onset location eventually moves upstream with a further increase in nose-tip bluntness. This transition-reversal phenomenon was the focus of a collaborative investigation under the NATO Science and Technology Organization (STO) Applied Vehicle Technology (AVT)-240 group. The current Paper provides an overview of that effort, which included wind tunnel measurements and theoretical analysis related to modal and nonmodal amplification of boundary-layer disturbances. Because modal amplification is too weak to initiate transition at large bluntness values, transient growth has been investigated as the potential basis for a physics-based model for the transition-reversal phenomenon. Results indicate that stationary disturbances that are initiated within the nose-tip vicinity can undergo relatively significant nonmodal amplification that increases with the nose-tip bluntness. This finding does not provide a definitive link between transient growth and the onset of transition but is qualitatively consistent with the experimental observations that frustum transition during the reversal regime was highly sensitive to wall roughness and, furthermore, was dominated by disturbances originating near the nose tip. The present analysis shows significant nonmodal growth of traveling disturbances that peak within the entropy layer and could also play a role in the transition-reversal phenomenon if those disturbances are realizable in a natural disturbance environment.

Genotype and clinical phenotype analysis in patients with retinitis pigmentosa and cone rod dystrophy

Objective To observe the gene mutation and clinical phenotype of patients with retinitis pigmentosa (RP) and cone rod dystrophy (CORD). Methods Thirty-seven patients with RP and 6 patients with CORD and 95 family members were enrolled in the study. The patient’s medical history and family history were collected. All the patients and family members received complete ophthalmic examinations to determine the phenotype, including best corrected visual acuity, slit lamp microscope, indirect ophthalmoscopy, color fundus photography, optical coherence tomography, full-field electroretinogram, and fluorescein fundus angiography. DNA was abstracted from patients and family members. Using target region capture sequencing combined with next-generation sequencing to screen the 232 candidate pathogenic mutations. Polymerase chain reaction and direct sequencing were used to confirm the pathogenic pathogenic mutations and Co-segregation is performed among members in the family to determine pathogenic mutation sites. The relationship between genotype and clinical phenotype of RP and CORD was analyzed. Results Of the 37 patients with RP, 13 were from 6 families, including 4 families with autosomal dominant inheritance, 2 families with autosomal recessive inheritance, and 3 in 6 families were detected pathogenic gene mutations. 24 cases were scattered RP. Six patients with CORD were from four families, all of which were autosomal recessive. Of the 43 patients, 21 patients were detected the pathogenic gene mutation, and the positive rate was 48.8%. Among them, 15 patients with RP were detected 10 pathogenic gene mutations including USH2A, RP1, MYO7A, C8orf37, RPGR, SNRNP200, CRX, PRPF31, C2orf71, IMPDH1, and the clinical phenotype included 10 typical RP, 2 cases of RPSP, 3 cases of Usher syndrome type 2 and 6 cases of CORD patients were all detected pathogenic gene mutations, including 2 cases of ABCA4, 2 mutations of RIMS1 gene, 1 case of CLN3 gene mutation, and 1 case of CRB1 and RPGR double gene mutation. Conclusions RP and CORD are clinically diverse in genotype and clinically phenotypically similar. For patients with early RP and CORD, clinical phenotype combined with genetic analysis is required to determine the diagnosis of RP and CORD. Key words: Retinal diseases/genetics; Retinitis pigmentosa/genetics; DNA mutational analysis; Phenotype

Advances of optogenetics in the treatment of retinitis pigmentosa

Retinitis pigmentosa (RP) is a disease that seriously affects vision. It mainly affects rod cells and causes night blindness. At the end of the disease, due to the simultaneous involvement of cone cells, the patient’s central vision and peripheral vision loss are not effective. There is no effective treatment method. However, some studies have found that although the function of photoreceptors is lost in the pathological process of RP, the function of bipolar cells and ganglion cells and the neural connection with the visual center are preserved, which provides a condition of therapeutic application in optogenetics for optogenetics. Optogenetics controls the excitability of neurons by expressing the light-sensitive protein represented by rhodopsin ion channel protein-2 on neurons, and has shown great application prospects in reshaping the photoreceptor function of the retina. The treatment of a type of retinal degenerative disease provides an effective treatment option. Key words: Retinitis pigmentosa/therapy; Optogenetics; Review