Cone Research Articles

Relative geometric assembly and mapping cones Part II: Chern characters and the Novikov property

We study Chern characters and the assembly mapping for free actions using the framework of geometric K-homology. The focus is on the relative groups associated with a group homomorphism phi: Gamma(1) -> Gamma(2) along with applications to Novikov type properties. In particular, we prove a relative strong Novikov property for homomorphisms of hyperbolic groups and a relative strong l(1)-Novikov property for polynomially bounded homomorphisms of groups with polynomially bounded cohomology in C. As a corollary, relative higher signatures on a manifold with boundary W, with pi(1)(partial derivative W) -> pi(1) (W) belonging to the class above, are homotopy invariant.

Analysis of the hypersonic cross-flow instability with experimental wavenumber distributions

Stationary cross-flow vortex N-factors were calculated over the surface of a yawed circular cone using computationally predicted and experimentally observed wavenumber distributions. Surface heat-flux data were obtained on a half-angle circular cone to investigate the behaviour of the stationary waves at different angles of attack and Reynolds numbers at Mach 6 under quiet-flow conditions in the Boeing/AFOSR Mach-6 Quiet Tunnel at Purdue University. A wavelet analysis was conducted on the experimental surface heat-flux data to construct a spatial mapping of the local largest amplitude wavenumbers of the stationary cross-flow waves, which were between 40 and 80 per circumference. Significant axial and azimuthal variation was observed. The results from the wavelet analysis were used to inform the stability analysis. The computed integration marching directions demonstrated very good agreement with the experimentally observed paths. N-factors were first calculated by integrating the local amplification rate corresponding to the most amplified experimental wavenumbers. The calculations were repeated based on non-dimensional computationally varying wavenumber ratios, which were dimensionalized by the experimental data. The computed N-factors showed good agreement between the two techniques. N-factors were also computed using the computationally predicted most unstable wavenumbers. The results showed decreased agreement with the other two cases, suggesting that this assumption does not properly model the cross-flow transition process.

A simple knowledge-based tool for stereotactic radiosurgery pre-planning.

We studied the dosimetry of single‐isocenter treatment plans generated to treat a solitary intracranial lesion using linac‐based stereotactic radiosurgery (SRS). A common metric for evaluating SRS plan quality is the volume of normal brain tissue irradiated by a dose of at least 12 Gy (V12), which is important because multiple studies have shown a strong correlation between V12 and incidence of radiation necrosis. Unrealistic expectations for values of V12 can lead to wasted planning time. We present a model that estimates V12 without having to construct a full treatment plan. This model was derived by retrospectively analyzing 50 SRS treatment plans, each clinically approved for delivery using circular collimator cone arc therapy (CAT). Each case was re‐planned for delivery via dynamic conformal arc therapy (DCAT), and then scaling arguments were used to extend dosimetric data to account for different prescription dose (PD) values (15, 18, 21, or 24 Gy). We determined a phenomenological expression for the total volume receiving at least 12 Gy (TV12) as a function of both planning target volume (PTV) and PD: TV12/1cc=n∗PD/1Gy+d∗PTV/1cca∗PD/1Gyc, where a,c,n,d are fit parameters, and a separate set of values is determined for each plan type. In addition, we generated a sequence of plots to clarify how the relationship between conformity index (CI) and TV12 depends on plan type (CAT vs DCAT), PTV, and PD. These results can be used to suggest realistic plan parameters and planning goals before the start of treatment planning. In the absence of access to more sophisticated pre‐planning tools, this model can be locally generated and implemented at relatively low cost with respect to time, money, and expertise.

Analysis of genotype and phenotype of hereditary retinal diseases which are easily misdiagnosed as amblyopia

Objective To analysis the genotype and phenotype of hereditary retinal diseases (HRD) which are easily misdiagnosed as amblyopia. Methods A case-control study was designed.The patients with HRD who were misdiagnosed as amblyopia in Ningxia Eye Hospital from January to December, 2017 were recruited in this study.The clinical medical history and ophthalmic examinations of patients and their family members were recorded, and family maps were drawed.Peripheral venous blood (5 ml) from each patient and their family members was collected, and genomic DNA was extract.The target sequence capture sequencing technology was used to detect the genetic testing in serum of the patient, and the pathogenic mutation site was determined by Sanger sequencing and co-segregation verification.Genetic testing results with related ophthalmic examination were considered together to analyze the relationship between genotype and phenotype.This study followed the Declaration of Helsinki.Written informed consent was obtained from each subject or the guardian prior to entering study cohort.This study protocol was approved by Ethic Committee of People's Hospital of Ningxia Hui Autonomous Region Hospital (No.2016018). Results Twenty-two patients with HRD were enrolled in the study, including 10 Stargardt disease (STGD), 8 cases of cone dystrophy (COD) or cone and rod dystrophy (CRD), and 5 cases of familial exudative vitreoretinopathy(FEVER). Nine patients were detected to have pathogenic mutations, and the positive rate was 40.9%, of which 4 patients with STGD carried mutation gene, including ABCA4 and PROM1 genes; mutations in RPGR, PROM1 and GUCY2D genes were detected in 3 patients with COD or CRD; TSPAN12 gene mutation were detected in 2 patients with FEVER.Eleven mutation sites were detected, 4 of which were newly discovered mutation sites.All of the patients in 9 HRD families developed symptoms during adolescence.At the early stage of the disease, there was severe damage to the eyesight, but the fundus was normal or only slightly abnormal.As the disease progressed, the fundus changes were characteristic, and there were clinical phenotypic overlap between some diseases.All family genotypes and clinical phenotypes were co-separated. Conclusions The main pathogenic gene of STGD is ABCA4 gene, and PROM1 gene can also cause partial STGD; COD and CRD have similar clinical manifestations, and the pathogenic genes also cross each other, and the genetic pattern is diverse; FEVER caused by mutation of TSPAN12 gene is autosomal dominant, and the mutation type has missense mutation and frameshift mutation.HRDs lack typical early clinical signs, and genetic diagnosis can provide pre-symptomatic diagnosis. Key words: Hereditary retinal disease; Genotype; Phenotype

Focus on stem cell-based therapy for retinal degenerative diseases

Retinal degenerative diseases are the common cause of blindness for all ages.Cell replacement therapy is the main strategy for treating retinal degenerative diseases.Recently, several retinal pigment epithelium(RPE) transplantation clinical trials have taken place worldwide and greatly enhanced the visual function of patients.However, irreversible loss of photoreceptors has been found in the late stage of diseases.Thus, photoreceptor transplantation is essential for the treatment of late-stage retinal degenerative diseases.How to obtain the clinical-grade amount of human cone photoreceptors remains to be one of the technical obstacles.This review introduced the present clinical trials of RPE transplantation and research achievements of photoreceptor transplantation.Furthermore, we will focus on the studies of stem cell-derived human photoreceptor differentiation.Lastly, the difficulties and future directions of stem cell-based therapy for retinal degenerative diseases will be discussed. Key words: Retinal degenerative diseases; Stem cell; Photoreceptor; Retinal pigment epithelium; Cell replacement therapy

Numerical Study of Natural Convection Flow of Nanofluid Past a Circular Cone with Cattaneo–Christov Heat and Mass Flux Models

The objective of this study is to analyze the natural convection flow of nanofluid along a circular cone placed in a vertical direction. The generalized heat flux and mass flux models are commonly known as the Cattaneo–Christov heat flux model and mass flux models. In the present study, these models are used for both heat and mass transfers analysis in nanofluid flow. For the governing equations, the Buongiorno transport model is used in which two important slip mechanism, namely thermophoresis and Brownian motion parameters, are discussed. The resulting governing equations in the form of partial differential equations (PDEs) are converted into ordinary differential equations (ODEs) due to similar flow along the surface of a circular cone. To solve these ODEs, a numerical algorithm based on implicit finite difference scheme is utilized. The effects of dimensionless parameters on heat and mass transfer in nanofluid flow are discussed graphically in the form of velocity profile, temperature profile, Sherwood number and Nusselt number. It is noted that in the presence of the Cattaneo–Christov heat flux model and mass flux model, the heat transfer rate decreases by increasing both thermal and concentration relaxation parameters; however, Sherwood number decreases by increasing the thermal relaxation parameter, and increases by increasing the concentration relaxation parameter.

$n$-fold hyperspaces as cones

For a continuum $X$, let $C_{n}(X)$ be the hyperspace of nonempty closed subsets of $X$ with at most $n$ components. In this paper we prove that if $X $ is a fan and $n\neq 2$, then $C_{n}(X)$ is a cone if and only if $X$ is a cone.

Gouy and spatial-curvature-induced phase shifts of light in two-dimensional curved space

Gouy phase is the axial phase anomaly of converging light waves discovered over one century ago, and is so far widely studied in various systems. In this work, we have theoretically calculated Gouy phase of light beams in both paraxial and nonparaxial regime on two-dimensional curved surface by generalizing angular spectrum method. We find that curvature of surface will also introduce an extra phase shift, which is named as spatial curvature-induced (SCI) phase. The behaviors of both phase shifts are illustrated on two typical surfaces of revolution, circular truncated cone and spherical surface. Gouy phase evolves slower on surface with greater spatial curvature on circular truncated cone, which is however opposite on spherical surface, while SCI phase evolves faster with curvature on both surfaces. On circular truncated cone, both phase shifts approach to a limit value along propagation, which does not happen on spherical surface due to the existence of singularity on the pole. An interpretation is presented to explain this peculiar phenomenon. Finally we also provide the analytical expression of paraxial Gaussian beam on general SORs. By comparing the result with the exact method we find the analytical expression is valid under the approximation that beam waist and scale of surface are beyond order of wavelength. We expect this work will enhance the comprehension about the behavior of electromagnetic wave in curved space, and further contribute to the study of general relativity phenomena in laboratory.

Experimental Lumped Analysis of Different Solid Geometries

Present work describes the experimental analysis of unsteady state heat transfer of different solid geometries. Heat transfer process in considered as a function of time only i.e. solid body behave as ‘Lumped’ means there is uniform temperature with in the body and having negligible internal thermal conduction resistance. The lumped analysis is done with cylindrical, conical and mixed geometry of cylinder and cone of two different materials. Specimens are heated in water ant cooled in air to estimate the heat transfer response of geometries in same ambient conditions MATLAB programming is done for calculation to obtain good and accurate results and to estimate heat transfer response of different geometries used in many engineering application.

Absorption Enhancement of Ultrathin Crystalline Silicon Solar Cells with Dielectric Si3N4 Nanostructures**Project supported by National Science Foundation of China (NSFC) (U1765105, 61604087); The Hebei Provincial Young Top-notch Talent Support Program (BJRC2013); Alexander von Humboldt-Stiftung (AUS-1141939-HFST-E)

A design of ultrathin crystalline silicon solar cell with Si3N4 circular truncated cone holes (CTCs) arrays on the top is proposed. In this article, we perform an optical simulation of the structure. The finite-difference time-domain method is used to calculate the optical absorption of different periods, radius of top and bottom circles and depth of Si3N4 CTCs. The short-circuit current density generated by the optimized cells (30.17 mA/cm2) is 32.44% more than the value gained by control group (with flat Si3N4). Then adding a layer of back silver to allow us to better analyze optical absorption. Later, we simulate the optimization of the same configuration of different silicon thicknesses and find that our structure does enhance the light absorption. This work uses a combined path towards achieving higher photocurrent ultrathin crystalline silicon solar cells by constructing the texture of anti-reflection coating.

Effect of Supersonic Nozzle Structure on Vapor Spontaneous Condensation

To study the effect of the supersonic nozzle structure on the spontaneous condensation of water vapor, the wet steam model used to study the wet steam liquefaction of steam turbine was introduced into the numerical study of supersonic nozzle in supersonic cyclone separator, and the numerical results was in good agreement with the experimental data of the related literature. The supersonic nozzles, the contraction section with the Witozinsky curve and the bicubic curve, and the expansion section with conical curve and Foelsch curves, were designed. The influence of supersonic nozzle structure on water vapour liquefaction ability was investigated. And the following research results were obtained. When the structure of the supersonic nozzle was the same, the Witozinsky curve was selected for contraction section of the supersonic nozzle, and the nucleation rate of the droplet in the nozzle increased by 21.97 % and the number of droplets increased by 32.16 %, which was helpful to the gas liquefaction in the nozzle. When the contraction curve of the supersonic nozzle was consistent, and the expansion curve was Foelsch curve, the gas nucleation rate and the number of droplets in the nozzle were greatly improved. The distribution of nozzle humidity was related to the structure of expansion section, but not to the structure of contraction section. The maximum humidity in nozzle depended on the outlet diameter of nozzle. When the other structures of the nozzle were consistent, the cone angle of divergent section increased from 2° to 8°, the peak value of the nucleation rate increased by 493.15 %, the maximum of the droplet number increased by 246.12 %, the outlet humidity of the nozzle increased by 73.37 %, which greatly improved the gas liquefaction rate. In the case of gas liquefaction, increasing the cone angle of expansion section was conducive to liquefaction of water vapor.

An imperceptible incorrectness in deriving data consistency condition from John’s equation for cone-beam CT imaging

A John’s equation-based consistency condition (JECC) and restoration of corrupted projection had ever been proposed for the circular trajectory cone beam CT (CBCT) imaging. They attempted to derive the so-called JECC, i.e., a data consistency condition (DCC) from John’s equation. Unfortunately, there is an imperceptible incorrectness in their derivation, which is disproved here by following the line of their thought. The basic cause leading to the imperceptible incorrectness is that John’s equation was incorrectly applied to a characteristic manifold.

An all-dielectric 3D Luneburg lens constructed by common-vertex coaxial circular cones

An all-dielectric broadband 3D Luneburg lens has been designed and manufactured in our study, which is constructed by common-vertex coaxial circular cones. A prototype of the lens is fabricated using 3D printing technology. The far field of the, present lens is highly directive, incident waves are focused with highly concentration, and its operating frequency spans from 5 GHz to 20 GHz. It is also found that two highly directional beams are generated while two independent converged sources feed simultaneously at the edge of the lens. The intersection angle with the center of the lens is 90°, which indicates that the lens is an efficient double input-double output device.

Effectiveness of chloral hydrate sedation in pediatric patients who receive cone beam computed tomography examinations

Objective To discuss the success rate and image quality in pediatric patients who used chloral hydrate before their cone beam computed tomography exam. Methods 1752 patients aged 1 to 6 were selected for this retrospective study. They were divided into sedated group (219 cases) and non-sedated group (1 533 cases). The success rate and image quality were compared between two groups. Results The sedated group had a higher success rate to non-sedated group: 99.5%(218/219) vs. 90.4% (1 386/1 533). The motion artifact in sedated group was lower than non- sedated group with I degree: 4.8% (15/314) vs. 20.1%(327/1 630) and II degree: 0.3%(1/314) vs. 12.2%(199/1 630). Conclusion Giving chloral hydrate to pediatric patients before their CBCT exam would improve both success rate and image quality, and reduce unnecessary radiation expose. Key words: Children; Chloral hydrate; Cone beam computed tomography

Design and application of compound conical horn with cylinder at big end

Design and application of compound conical horn with cylinder at big end

A Multi-Platform Treatment Planning Benchmark Study for Spinal Radiosurgery

Technological development in radiotherapy (RT) provides new treatment options for complex spinal radiosurgery. Sophisticated RT delivery platforms using image-guidance and target-tracking methods call for to understand the minute differences. We present a comparative planning of different approaches for external RT assessed to a previously published best practice benchmark. The initial benchmark (first)a case, was a pretreated complex spinal lesion. The second case was a pretreated fractured spinal lesion. The third one was a small lesion to be treated with integrated boost. 12 centers with various platforms for spinal radiosurgery were took part in this study. The plans were compared against a complex spinal benchmark plan derived for robotic radiosurgery using circular cones only. A previously established mathematical group ranking system based on a scale from 1 to 4 with 1 being good or excellent, 2 being average, 3 being below average and 4 being relatively poor was used for relative plan quality comparison. All challenge plans were able to reach equality (n = 4) or outperform (n = 8) the reference benchmark plan based on the aforementioned ranking system. Only 5 plans for the second and 3 plans for the third case reached equality or outperformed the best practice benchmark plan. However, the overall average ranking for all volumetric modulated arc therapy (VMAT) plans was 1.2 (range 1.0–1.3), while for all robotic radiosurgery (RRS), helical radiotherapy (HRT) and static field intensity modulated radiation therapy (SF-IMRT) plans the average ranking was 3.1 (range 2.3–4.0), 3.3 and 3.8 (range 3.7–4.0), respectively. Although it may be debated on treatment time and MU role for treatment plan quality, all plans were ranked again without considering delivered MU as factor. Here, the overall average ranking for all VMAT plans was 1.4 (range 1.3–1.7), while for all RRS, HRT and SF-IMRT plans the average ranking was 2.4 (range 2.0–3.0), 3.0 and 3.9 (range 3.7–4.0), respectively. No significant difference was found between the four different planning strategies VMAT, HRT, SF-IMRT, and RRS: p = 0.02 for Kruskall–Wallis and p = 0.01 for the median test. By comparing two different techniques with each other, statistically meaningful differences between VMAT and RRS (p = 0.002) were found, but not between SF-IMRT and RRS (p = 0.322). Nevertheless, the statistical analysis has to be taken with caution due to the number of cases (n = 3) and the maximum number of each planning strategy (n = 1–5) being used. High plan quality for complex spinal radiosurgery was noticed among all platforms and all participating centers in this planning challenge. Simple VMAT technique using one or two arcs provides an acceptable alternative and better plan quality to compare to previous established robotic radiosurgery benchmarks. This study also demonstrated that for spine treatment the RRS with MLC was not able to outperform the standard circular cones.

Improvement in the Performance of a Solar Hot Air Generator Using a Circular Cone

In this work the design and the study of a solar hot air generator, using concentrated solar radiation are proposed. This generator consists of a circular disc heated by the radiation reflected by a parabolic collector. The disc is placed at the entrance of an opened vertical cone. Under the thermal radiation effect emitted by the hot source, the internal wall of the generator is heated. The heating of the air at the generator-inlet generates a thermosiphon flow that is added to the one created by the hot source. In order to determine the critical parameters, the local convective transfer along the generator wall as well as the thermal and dynamic fields of the hot air at the cone exit for different angles and ratios of the rays are studied. It has been found out that the critical parameters of the conical generator, from which the thermal and dynamic characteristics of the hot air produced are R*=0.5; C=0.65; α=8°, have significantly improved. A comparative study of the hot air characteristics at the exit of the optimal conical generator, with two cylindrical and rectangular generators of the same geometrical characteristics is realized. The obtained results reveal relative increases of the mass flow rate of 78% and the heat flux absorbed by the air of 116% at the exit of the optimal cone compared to the cylinder. The results show also relative increases of the air temperature and the thermal flux absorbed by the air respectively of 400% and 129% at the exit of the optimal cone compared to the channel. A correlation between the hot source temperature and the air temperature at the exit of the optimal conical generator has been determined.

Accuracy of IOS in Full-Arch Dentate Patients Compared to CBCT Cast-Scanning. An In-Vivo Study.

Twenty fully-dentate patients were enrolled in the study.Full-arch maxillary and mandibular PVS impressions were acquired using stock metal trays and the dual mix technique. A full-arch maxillary and mandibular intraoral scanner (IOS) was also obtained using the Trios IOS. The impressions were cast and subsequently scanned using a Planmeca Promax cone beam computed tomography (CBCT) scanner. The casts were also scanned in a Desktop Scanner for reference(7series Dental Wings). DICOM files from the CBCT device were converted into stl files. The.stl files from the CBCT and IOS devices were compared for accuracy against the reference files from the Desktop Scanner using a 3D surface measurement software. Statistical analysis was carried out using SPSS software. Trios had a smaller error (median = 39μm) than CBCT (median = 62μm),a statistically significant difference between the 2 modalities (z=-4.6, p⟨0.005).Concerning the IOS, the anterior teeth presented with a smaller error (42±16μm) as opposed to the posterior teeth (47±16μm), a significant difference (t(39)=-2.4, p=0,019). There were no significant differences in IOS mean accuracy between maxilla and mandible or between left and right quadrants. Fullarch digitization using the Trios IOS is significantly more accurate compared to CBCT scanning of the relevant plaster models. Anterior teeth Trios IOS is statistically more accurate compared to posterior teeth IOS.

Application of CT image registration in the radiotherapy of uterine cervical neoplasms based on 3D Slicer software

Objective To investigate the application of CT image and cone beam computed tomography (CBCT) image registration based on 3D Slicer software in image-guided radiotherapy for uterine cervical neoplasms. Methods Based on 3D Slicer software and Slicer RT toolkit, 10 positioning CT images and 50 CBCT images of 10 patients with uterine cervical neoplasms in Henan Provincial People's Hospital between January 2018 and October 2018 had rigid registration and b-spline deformation registration respectively. The dice similarity coefficient (DSC) and Hausdorff distance (HD) of the bladder, rectum, femoral head, spinal cord, and body of CT-CBCT images were compared by using paired t-test before and after the registration. Results Pre-registration, rigid registration and after b-spline deformation registration of CT images and CBCT images, the DSC in the bladder (0.459±0.177, 0.528±0.184, 0.542±0.187, respectively), the rectum (0.564±0.141, 0.632±0.091, 0.684±0.097, respectively), the femoral head (0.695±0.088, 0.833±0.030, 0.865±0.027, respectively), the spinal cord (0.587±0.119, 0.746±0.085, 0.834±0.032, respectively) and the body surface (0.922±0.013, 0.948±0.011, 0.959±0.009, respectively) showed an increased trend; HD in the bladder (12.8±7.2, 12.2±7.1, 11.7±7.3, respectively), the rectum (5.0±1.8, 4.4±1.2, 3.4±1.2, respectively), the femoral head (3.6±1.2, 1.8±0.5, 1.5±0.5, respectively), the spinal cord (4.0±1.0, 2.7±1.3, 1.8±0.5, respectively) and the body surface (6.3±2.1, 5.2±2.0, 4.3±2.0, respectively) showed a decreased trend. The differences of pairwise comparison in the same parts were statistically significant (all P < 0.05). Conclusions Both rigid registration and b-spline deformation registration of CT-CBCT images based on 3D Slicer software can improve the radiotherapy accuracy of uterine cervical neoplasms, and b-spline deformation registration has more significant advantages. Key words: Uterine cervical neoplasms; Radiotherapy; 3D Slicer software; Cone-beam computed tomography; Image registration; Image-guided radiation therapy

Prophylactic operation for asymptomatic spinal lipomas in children

Objective To explore the clinical outcome and value of prophylactic operation of asymptomatic spinal lipomas in children. Methods We retrospectively analyzed the clinical data of 168 patients with asymptomatic spinal lipomas who underwent prophylactic operation from April 2001 to June 2015 at Department of Neurosurgery, Shanghai Children's Medical Center, School of Medicine, Shanghai Jiaotong University. Those patients (with an average age of 7 months) aged from 1.5 months to 15 years old were free of preoperative symptoms such as pain, gatism and/or bilateral lower limb dysfunction. Surgical protocols included removal of the lipomas in subcutaneous and extramedullary tissues, complete excision of extraspinal lipomas, subtotal resection of intraspinal fat, detaching of the medullary cones from dura sac and release of the tethered cord. Results In 168 patients, complete resection was achieved for the dorsal spinal lipoma(132 patients) and subtotal resection was undertaken for the lateral type and the wrapped lipoma(36 patients). Five cases developed cerebrospinal fluid leakage that caused subcutaneous effusion after surgery, which resolved following multiple punctures and pressure dressing. Six patients had slight gatism. Among them, 5 recovered in 1 month and 1 had no relief of symptoms. In this series, 159 out of 168 cases were successfully followed up for 3-19 years (with an average of 76 months). Long-term postoperative symptoms were observed in 13 patients, with an incidence of 8.2%. Twelve patients of them had spinal cord retethering and 1 had lipoma enlargement. Conclusion Prophylactic surgery could lead to favorable outcomes in children with asymptomatic spinal lipomas and help prevent neurologic dysfunction in the future. Key words: Spinal cord; Lipoma; Neurosurgical procedures; Prognosis