Rotation Of Plane Research Articles

Effects of pendulum appliance versus clear aligners in the vertical dimension during Class II malocclusion treatment: a randomized prospective clinical trial

BackgroundThe aim of the present study was to compare the effects on vertical dentoskeletal dimension produced by Pendulum appliance and Clear Aligners in patients with Class II malocclusion.Trial designThis is a prospective two-arm parallel group randomized clinical trial with 1:1 allocation ratio.MethodsThe Pendulum Group (PG) consisted of 20 patients (15F, 5 M) with a mean age of 17.2 ± 4.3 years. The Clear Aligners Group (CAG) comprised 20 patients (13F, 7 M) with a mean age of 17.2 ± 3.2 years. Distalization’s protocol in PG involved the activation of TMA wires till the achievement of Class I molar relationship. A protocol of sequential distalization was applied in the CAG. For each subject lateral cephalograms have been analyzed before treatment (T1) and at the end of the therapy (T2). Descriptive statistics and statistical between-group comparisons (PG vs CAG) were calculated for the craniofacial starting forms at T1 and for the T2–T1 changes. Statistical between-group comparisons for the T2–T1 changes were performed with independent samples t-tests (P < 0.05).ResultsThe PG showed significantly greater increases in SN^GoGn° when compared with CAG (+ 2.1 and − 0.3 degrees, respectively). Clockwise rotation of the occlusal plane with significantly greater increase of SN^POccl angle was observed in PG (+ 2.8 degrees) when compared with CAG (− 4.2 degrees).The PG revealed a significant increase in the N-Me variable with a mean change of + 4.4 mm compared to the CAG with mean values of − 1.2 mm. The PG showed an increase in the ArGo^GoMe angle (+ 0.7° degrees) compared to the CAG (− 3.4° degrees). The PG showed significantly greater increases in both maxillary and mandibular first molar to palatal plane (+ 1.3 and + 2.1 mm, respectively) when compared with CAG (− 0.9 and − 0.2 mm, respectively).ConclusionsUpper molar distalization with clear aligners represents a valid alternative to non-extraction treatment of Class II malocclusion, reducing the extrusion of maxillary first molars and improving the management of the occlusal plane and vertical dimension.Trial registration: ClinicalTrials.gov, NCT05298280. Registered 28 March 2022—Retrospectively registered, https://clinicaltrials.gov.

Impact of Capsulotomy on Hip Biomechanics during Arthroscopy.

Background and Objectives: Anterior capsulotomy is routinely performed in hip arthroscopy to improve joint visualization; however, this can partly or completely disrupt the stabilizing ligaments of the hip. This study aimed to report the effects of conventional and extensive arthroscopic capsulotomies on hip stability. Materials and Methods: Eight freshly frozen cadaveric pelvises were used in this study. The range of motion and translation were measured and compared among different capsular conditions utilized in hip arthroscopy, with a special interest in the iliofemoral ligament (IFL) and zona orbicularis (ZO). The conditions included intact capsule, interportal capsulotomy, T-capsulotomy, complete IFL disruption, and complete IFL and ZO disruption. Internal rotation at three flexion planes (−10°, 0°, and 30°) and external rotation at six flexion planes (−10°, 0°, 30°, 60°, 90°, and 110°) were measured with corresponding femoral head translation distance at the application of 2.5 Nm torque. Results: As compared to an intact capsule, a significant increase in external rotation was observed after interportal capsulotomy from −10° to 60° and after T-capsulotomy from −10° to 110° flexion. A significant translation was observed only with a T-capsulotomy, which ranged from 1.9 to 2.3 mm across the flexion angles. Compared with conventional interportal capsulotomy, disruption of the entire IFL resulted in a significant increase in external rotation in all flexion planes, and significant translation was accompanied by disruption of the ZO. Conclusions: Interportal capsulotomy can result in an increase in range of motion, and T-capsulotomy can lead to significant translation. Partial or complete tears of the IFL and ZO can result in further external rotation and translation.

Management of atypical occlusal discrepancy after condylar resection: A clinical report

This clinical report describes the prosthetic management of occlusion for a patient who had received condylar resection as part of cancer treatment. Previous reports have identified that patients with unrepaired segmental resection of the mandible experienced a frontal plane rotation of the mandible toward the nonsurgical side. In contrast, because of preservation of temporomandibular muscles and their attachments, the mandible rotated toward the surgical side, and occlusal contacts were limited to a pair of molars on that side. Manual manipulation and instructions for muscular stretching and massages were provided to reduce muscular tension. A mandibular guidance prosthesis was fabricated and gradually adjusted to guide the mandible progressively toward a normal position. These treatments helped improve general comfort, mastication, occlusion, and the gradual rotation of the mandible toward a normal position.

GNSS Signal Processing Based Attitude Determination of Spinning Projectiles

This article presents a global navigation satellite system (GNSS) based attitude (pitch, roll, and heading) determination method for spinning objects by estimating the unit vector along the projectile nose and the antenna pointing vector that lies radially in the plane of rotation. A theoretical framework of a spinning platform is developed by exploiting the periodic variations of the received signal. The presented method provides a drift-free attitude determination of spinning projectiles directly in earth-centered earth-fixed reference. The scheme may find a good combination with low-cost small projectiles where the provision of advanced inertial sensors is constrained by cost and installation space. The proposed solution can be adopted for different degrees of accuracy and computational complexity. The performance guarantee for the proposed algorithm is established using simulated data and real GNSS data. For real satellite signals, the performance results are validated using an experimental setup having a roll rate of around 750 r/min.

In-situ TEM study on the evolution of dislocation loops and bubbles in CeO2 during Kr+ single-beam and Kr+-H2+ dual-beam synergetic irradiation

CeO2 is widely used as the nonradioactive surrogate fuel of UO2 when studying the irradiation performance of UO2. The evolution and characteristics of dislocation loops and bubbles in CeO2 foils were studied by in-situ transmission electron microscopy (TEM) observation during 400 keV Kr+ & 30 keV H2+ dual-beam synergetic irradiation and 400 keV Kr+ single-beam irradiation at 1073 K. The rotation of the habit plane of dislocation loops induced by above ion irradiation was found in the CeO2 for the first time, such as from [2¯11¯] to [3¯11¯] and then to [1¯00]. The rafted loops were first observed under Kr+ & H2+ dual-beam synergetic irradiation, which not only had similar [1¯11¯] direction, but also belonged to perfect dislocation loops (PDLs). The rafted loops were formed not only by the growth of loops that absorbed irradiation defects, but also by the combination of loops. But, this phenomenon of loop rafting was not obvious during Kr single-beam irradiation. It was first found that Kr+ irradiation induced the change of Burgers vectors of PDLs. The absorption of large PDLs to small PDLs was also observed. The average size and areal number density of dislocation loops and gas bubbles as a function of irradiation dose were constructed, which showed that the addition of H2+ obviously affected the characteristics of dislocation loops and gas bubbles and the swelling of CeO2.

Sesamoid View X-ray vs Weightbearing Computed Tomography in the Measurement of Metatarsal Pronation Angle

Category: Bunion; Midfoot/Forefoot Introduction/Purpose: First metatarsal (M1) axial rotation as measured by the metatarsal pronation angle (MPA) has increasingly become recognized as a clinically relevant component of hallux valgus deformity and methods to realign the M1 in 3 dimensions have been developed. Preoperative imaging with weightbearing computed tomography (WBCT) is considered the best way to image and measure the MPA, however WBCT is not available to many foot and ankle surgeons. The aim of this project is to investigate if the MPA measured on sesamoid view weight bearing radiographs is similar to that measured on WBCT. Methods: A retrospective analysis of patient imaging studies was performed. We identified 25 feet with both sesamoid WBR and WBCT images from a consecutive patient database. Included subjects had no trauma or foot and ankle operation between acquisition of the two scans. MPA of the WBCT for each patient was initially measured. After an appropriate washout period, the observer then measured MPA of the WBR for the cohort. Demographic statistics were calculated, a paired t-test was performed to evaluate for any significant difference in angular measurement between the two scans. Results: Patient characteristics: mean age 53 +- 16 years, mean BMI 32 +- 8 kg/m2, 13 right and 12 left feet, 19 females and 6 males. Average time between sesamoid view WBR and WBCT was 5.7 +- 9.5 months. Mean difference in MPA between WBR and WBCT = 0.6 +- 3.9 degrees (p= 0.444, t=0.777). Conclusion: Among the cohort assessed, we found no significant difference present in the measurement of the metatarsal pronation angle as evaluated on sesamoid view weightbearing radiography compared with weightbearing computed tomography (Figure 1). Routine acquisition of a sesamoid view weightbearing radiograph may be considered as an appropriate substitute for weightbearing computed tomography in the preoperative evaluation of M1 rotation in the coronal plane. These findings may benefit physicians who do not have access to weightbearing computed tomography in their clinics.

3-Dimensional Analysis of First Tarsometatarsal Joint after First Metatarsal Osteotomy with Weightbearing CT (WBCT)

Category: Midfoot/Forefoot; Bunion Introduction/Purpose: The pathology of the bunion deformity consists of deformities in the axial, coronal, and sagittal planes of the first metatarsal and its articular surface with the medial cuneiform. While weightbearing radiographs have been utilized for assessment of these deformities, such methods have limitations with regard to image magnification, patient position, and superimposition of bone alignments. With advances with weightbearing computed tomography (WBCT), evaluation of the 3- dimensional components of the first metatarsal along with its proximal articular surface can be assessed with greater precision. This study aims to observe the effect of the midshaft osteotomy on the alignment of the tarsometatarsal joint in three dimension Methods: Ten feet in 10 subjects underwent midshaft first metatarsal osteotomies. Weight-bearing (using a load equivalent to body weight) CT scans with .3mm cubic voxel size using an original loading device preoperatively and postoperatively were collected from each of the subjects in neutral standing position. Scans were segmented, and 3D renderings of the medial cuneiform, first metatarsal, and the first phalanx were also generated from the segmentations followed by definition of reference frames to evaluate changes in the metatarsal in relationship to the medial cuneiform. (Fig.1) Results: The measurements of the rotational parameters showed greater changes in the sagittal plane postoperatively with dorsiflexion of the first metatarsal relative to the medial cuneiform at the first tarsometatarsal joint (p&lt;0.05).(Fig.2) Post-operative changes in the coronal plane and axial plane with relationship of the first metatarsal to the medial cuneiform were noted. Distance mapping showed a significant increase in surface-to-surface distance at the dorsal tarsometatarsal joint post-operatively with a reduced distance at the inferior portion of the tarsometatarsal joint. (Fig.3). Conclusion: Based on the results of the study, midshaft osteotomies of first metatarsal can cause increased dorsiflexion in the sagittal plane, significant eversion in the coronal plane, and external rotation in the axial plane at the tarsometatarsal joint. Distance mapping analysis on WBCT images identified differences in surface-to-surface interaction of the first metatarsal and the medial cuneiform

Coronal Plane Rotation of the Medial Column in Hallux Valgus (HV), Progressive Collapsing Foot Deformity (PCFD), and Combined PCFD HV: A Retrospective Case Control Study

Category: Bunion; Hindfoot; Midfoot/Forefoot Introduction/Purpose: The presence of hyperpronation of the first metatarsal (M1) seems to have a clinically significant role in Hallux Valgus (HV). Some authors reported a decrease in recurrence rates after M1 hyperpronation correction in HV. However, when measuring the M1 head pronation relative to the ground, we are assessing and quantifying the aggregate coronal rotational profile of each bone and joint throughout the medial column. Therefore, we do not know the location of this hyperpronation. Moreover, studies showed a strong influence of the hindfoot alignment on coronal rotational measurements and Progressive Collapsing Foot Deformity (PCFD) is a condition frequently associated with HV. Our study aimed to assess and compare coronal plane alignment of medial column bones in HV, PCFD, PCFD HV and controls. Methods: We performed a retrospective IRB approved study. We collected 33 feet who consulted our center with combinations of symptomatic PCFD and HV. We then matched 33 HV, 33 PCFD, and 33 controls for BMI, Gender, and Age to this group. We assessed the coronal plane rotation of the navicular, medial cuneiform, M1 at its base and head, the Sesamoid Rotation Angle (SRA) with respect to the ground, and the hallux valgus angle (HVA) using Weight-Bearing CT images (Figure).The positions of the different joints (first naviculocuneiform (NC1), first tarsometatarsal (TMT1) and metatarsosesamoid rotation angle (MSRA)) were found by subtracting the adjacent angles. Intrinsic torsion of M1 was calculated by subtracting the M1 base angle from the M1 head angle.Normality of different variables was assessed using the Shapiro-Wilk test. Groups were compared using t test or ANOVA for normal and Mann Whitney or Kruskal Wallis for nonnormal variables. Results: HV, PCFD and PCFD HV presented higher M1 intrinsic torsion when compared to controls (respectively 7.3°[CI95%:2.9-11.7], p&lt;0.001; 7.5°[CI95%:2.5-12.6], p&lt;0.001; 7.5°[CI95%: 2.9-12],p&lt;0.001).The navicular was more pronated in PCFD HV compared to controls (respectively 20+/-5.2° vs 12.5+/-3.9°,p&lt;0.001) whereas it was not for PCFD and HV.NC1 was 6.8° significantly more supinated in HV (p&lt;0.001) and 5.7° in PCFD HV (p&lt;0.001) compared to controls whereas there was no significant difference between PCFD HV and Controls.TMT1 was 7.3° significantly more pronated in HV (p&lt;0.001) and 4.9° in PCFD HV (p&lt;0.001) compared to controls whereas there was no significant difference between PCFD HV and Controls. MSRA was significantly higher in HV (p&lt;0.001) and PCFD HV (p&lt;0.001) compared to controls whereas there was no significant difference between PCFD and Controls. In multivariate analysis, MSRA (β=0.95,[0.83;1.07], p &lt;0.0001) were associated with higher values of HVA whereas NC1 (β=-0.24,[-0.42;-0.06], p= 0.0076) were associated with lower values of HVA. Conclusion: The intrinsic increase in M1 pronation appears to be a shared developmental abnormality in PCFD and HV. Combination of PCFD and HV seems to originate from the presence of a paradoxical supinatory malposition of the NC1 which was not present in PCFD without HV in our study. The presence of this compensatory supination malposition might explain the presence of HV by causing a metatarsosesamoid dislocation in HV and PCFD HV. In contrast, hyperpronation compensation in PCFD without HV might be proximal to the navicular because there was no difference between PCFD and control regarding the navicular position in our study.

Foot and Ankle Offset (FAO) Does Not Reflect the Actual Hindfoot Alignment in Cases Involving Ankle and/or Sagittal Foot and Ankle Deformities

Category: Hindfoot; Ankle; Midfoot/Forefoot Introduction/Purpose: The foot and ankle offset (FAO) was developed as a 3D biometric tool to measure hindfoot alignment on weightbearing CT (WBCT) scans. It corresponds to the offset between the hindfoot-to-forefoot midline and the talus and is reported as a percentage of foot-length. (1) Recently, with increased availability of WBCT in both research and clinical practice, the FAO has been widely used for hindfoot alignment assessment. (2) However, after extensive review of WBCT scans the authors of this study have noticed that FAO has a high false negative rate. This study aimed to demonstrate why FAO is inadequate in assessing 3D hindfoot alignment using both case examples and mathematical algorithms. Methods: This was a retrospective study including a cohort of 31 cases with various clinical diagnoses selected from a data base of WBCT in 260 patients. The deformities included valgus or varus ankle deformities, hindfoot deformities combined with sagittal plane deformities of the foot and ankle, rocker bottom foot deformity, ankle equinus, metatarsus primus elevatus, and first metatarsal plantarflexion. All of the latter deformities caused one or more parts of the triangular base for FAO evaluation (the 1st metatarsal, the 5th metatarsal and the calcaneus) to remain off the floor. The medical charts and WBCT scans of each patient were reviewed to evaluate the deformities in more detail. The FAO was measured by two fellowship trained foot and ankle surgeons separately. The clinical and radiographic diagnoses were compared with the FAO value to determine the accuracy and utility of the latter measurement. Limitations of FAO as a semi 3D tool using the tripod theory in assessing the hindfoot alignment were also demonstrated mathematically. Results: For each of these 31 cases examined, the hindfoot alignment information reflected by the FAO value was vastly different from the clinical and imaging study findings. (Table 1). Using the reference value for FAO (Normal 2.3% ± 2.9%, Varus −11.6%± 6.9%, and Valgus 11.4% ± 5.7%), 24 out of 31 cases in the cohort had a normal FAO value, however, among them there were 7 with a valgus ankle or distal tibia plus a normal or cavovarus hindfoot, 2 varus ankles with a normal hindfoot, 1 varus ankle with a valgus hindfoot, 3 cavovarus feet, 1 clubfoot, 1 equinus ankle with cavovarus foot, 2 equinus ankle with severe valgus hindfoot, 4 severe valgus hindfoot and 1 varus hindfoot with sagittal plane deformities, 2 Muller Weiss Disease; 5 out of 31 cases had a varus FAO value, but they all had a valgus ankle with either a varus hindfoot or sagittal plane deformities; 2 out of 31 cases had a valgus FAO value, however both cases had a valgus ankle with a varus hindfoot. Thorough algorithm and geometric evidence were provided. Conclusion: FAO has a very limited capacity to reflect hindfoot deformities, understandable when analyzing how the FAO is designed and measured mathematically. It is not a 3D tool. It does not include the level of the ankle nor the tibia, therefore it is not appropriate nor capable to be used as a hindfoot alignment evaluation tool. The tripod and talus projection theories cannot reflect sagittal plane deformities or coronal plane rotation, and false results are inevitably generated. Reference: 1. Lintz F, Barton T, Millet M, Harries WJ, Hepple S, Winson IG. Ground reaction force calcaneal offset: a new measurement of hindfoot alignment. Foot Ankle Surg. 2012;18(1):9-14. 2. de Cesar Netto C, Day J, Godoy-Santos AL, Roney A, Barbachan Mansur NS, Lintz F, Ellis SJ, Demetracopoulos CA. The use of three-dimensional biometric Foot and Ankle Offset to predict additional realignment procedures in total ankle replacement. Foot Ankle Surg. 2022 Feb 16:S1268-7731(22)00036-4.

Dual-Rod Instrumentation Via the Anterior Approach for Thoracolumbar and Lumbar Adolescent Idiopathic Scoliosis

Background: Posterior spinal fusion with pedicle screw instrumentation is currently the standard technique for spinal surgery. However, the anterior approach remains useful for thoracolumbar and lumbar (TL/L) lesions, such as in adolescent idiopathic scoliosis (AIS) 1–4 and spinal injuries 5,6 . We previously documented that long-term radiographic findings and clinical measures were satisfactory in patients with TL/L AIS treated with anterior dual-rod instrumentation 1 . Description: This surgical technique is indicated for single TL/L (Lenke 5) curves and is performed with use of extrapleural retroperitoneal approaches. The extrapleural cavity is connected to the retroperitoneal space by diaphragmatic transection. The lateral aspect of the vertebral bodies is exposed by retracting the psoas major muscle posteriorly from the intervertebral discs. Segmental vascular bundles are divided with coagulation and/or ligation. Care should be taken to reflect the psoas in its entirety and avoid an intramuscular approach to prevent bleeding injury to nerves, including the femoral, ilioinguinal, and genitofemoral nerves, as well as ureteral injury. After the intervertebral discs and cartilage plates are removed to the vertebral end plates, 2 screws are inserted in each vertebral body through a vertebral staple 1,4 . The anterior rod is then placed in the screw heads and rotated anteriorly, providing 3-dimensional correction of kyphotic deformities with lordosis production 1,4 . After the posterior rod is applied in the same manner as the anterior rod, compression forces are applied between the screws to correct scoliosis 1,4 . The compression force is first applied to the posterior rod so that kyphosis can be corrected more effectively 1,4 . Alternatives: Posterior pedicle screw instrumentation techniques are widely utilized for TL/L AIS curve correction. However, anterior techniques have frequently also been applied to the curve. Dwyer et al. 7 first reported the use of anterior spinal fusion (ASF) with a single braided cable connecting vertebral screws for the treatment of TL/L AIS, and Zielke et al. 8 modified that procedure by replacing the cable with a threaded rod. Although these instrumentation techniques and other single anterior rod techniques such as the Texas Scottish Rite Hospital System effectively correct scoliosis in the coronal plane and improve vertebral derotation 1,9 , poor sagittal and rotational plane deformity correction, implant weakness, and high incidence of pseudarthrosis remain unresolved issues 1 . Rationale: The fundamental advantages of the anterior approach in dual-rod instrumentation are the ability to achieve 3-dimensional correction with extremely low rates of pseudarthrosis and implant failure 1,10–12 . Furthermore, the fusion is expected to include fewer motion segments than with posterior systems (usually 1 level less distally and proximally). However, low skeletal maturity and a TL/L to thoracic Cobb ratio of &lt;1.25 appeared to be important factors for postoperative curve progression of the thoracic coronal deformity following ASF for the treatment of Lenke 5 curves 1,13 . In addition, subjacent disc wedging may occur when the subjacent disc is nearly parallel before surgery 1,14 . Expected Outcomes: The described technique is expected to provide 3-dimensional spinal correction. In a previous study, 30 patients with Lenke 5 AIS were followed for a mean of 17 years 1 . The mean TL/L Cobb angle correction rate and correction loss were 79.8% and 3.4°, respectively, at the time of the latest follow-up 1 . The average percent of predicted forced vital capacity and of forced expiratory volume in 1 second were 91.8% and 81.8%, respectively 1 . The average total score on the Scoliosis Research Society-30 outcome instrument was 4.21. No instrumentation failure, pseudarthrosis, or clinically relevant neurovascular complications were observed 1 . Important Tips: This technique is applicable to Lenke 5 AIS curves. However, the anterior approach can also be utilized for other TL/L lesions.The anterior procedure is accomplished via extrapleural retroperitoneal approaches with diaphragmatic transection.Care should be taken to reflect the psoas in its entirety and avoid an intramuscular approach to prevent bleeding and nerve and ureteral injuries. Acronyms &amp; Abbreviations: SRS-30 = Scoliosis Research Society-30

Research on intelligent assembly method of aero-engine multi-stage rotors based on SVM and variable-step AFSA-BP neural network

The quality of the aero-engine rotors assembly determines the overall performance of the engine. Aiming at the problems of rotors assembly with different plane types, we proposes a rotor plane classification method based on SVM by using the profile data of PCA dimension reduction. Meanwhile, for the unilateral-tilt plane rotors, the three-objective rotors assembly method of coaxiality, unbalance amount and perpendicularity based on the rigid rotor model is established. For the hyperbolic paraboloid rotors, an intelligent assembly method based on AFSA-BP neural network for coaxiality, unbalance amount and perpendicularity is established. The experiment is based on the double-column ultra-precision measuring instrument and V4L vertical balancing machine and HL5UB horizontal balancing machine to measure rotors geometry and unbalance data. The experimental results show that the plane type classification accuracy can reach 99 %. The prediction error of the coaxiality of the unilateral-tilt plane rotors assembly is 5.1 μm, the prediction error of the unbalance amount is 196 g·mm, and the prediction error of the perpendicularity is 0.6 μm. The average prediction error of the coaxiality of the hyperbolic paraboloid rotors assembly is 0.9 μm, and the average prediction error of the unbalance amount is 73 g·mm, and the average prediction error of the perpendicularity is 0.2 μm. Our method provides a reliable assembly solution for aero-engine rotors assembly and meets actual assembly requirements.

Irregularities in a metal-dielectric shielded waveguide with low losses for the frequency range 90–100 GHz

This article is devoted to the study of waveguide metal-dielectric structures in the frequency range of 90100 GHz with low losses up to 0,05 dB/m. The paper considers the effect of sharp irregularities on a section of a regular line, which leads to a change in the parameters of a metal-dielectric closed waveguide path. In practice, irregularities have a negative impact on the transfer characteristic of the waveguide. Therefore, the types of irregularities often found in modern devices were investigated. As a result of the analysis of the losses caused by the rupture of the dielectric rod and the rotation of the polarization plane, the approximated characteristics of the transfer function of the waveguide line with irregularity were obtained.

Practice of the visual determination of the direction of light polarization plane rotation in the gyrotropic uniaxial single crystals

When studying and applying crystals of the middle category, it is necessary to take into account the manifestations of anisotropy of their properties, in particular, optical anisotropy. One of the manifestations of optical anisotropy is the rotation of the polarization plane (gyrotropy effect), which is observed in the direction of the optical axis of such crystals. The plane of polarization of light can rotate clockwise and counterclockwise. To determine the direction of rotation of the polarization plane, simple visual methods can be used based on studies of samples in converging polarized light – observations of conoscopic figures. In general, the type of conoscopic figures depends on the relative position of the polarizers, the wavelength of light in the system, the cut of the single crystal perpendicular to which the light propagates, the thickness of the sample and the birefringence. The direction of rotation of the polarization plane can be determined by еру change of the type of conoscopic figure of a sample of a gyrotropic crystal cut perpendicular to the optical axis: change of the central spot color during the analyzer rotation; the extinction of the central spot when observing a conoscopic figure using light filters; the direction of movement of the rings in monochromatic light; observation of Airy patterns. According to the experience of working in our laboratory “Single crystals and Stocke on their Base”, the simplest, most operational and unambiguous visual method for determining the direction of rotation of the polarization plane is the observation of Airy figures. A conoscopic pattern in the form of Airy figures (a four-way spiral) occurs when observing in converging polarized light a combination of two superimposed samples of gyrotropic crystals cut perpendicular to the optical axis, rotating the plane of polarization of light in opposite directions. To use this method, a well-known sample of a gyrotropic crystal cut perpendicular to the optical axis is required.

Assessing Agreement Between Upright and Supine Head Roll Tests for Horizontal Semicircular Canal Benign Paroxysmal Positional Vertigo

Background and Objectives The newly introduced upright head roll test (UHRT), which exploits head rotations in the roll plane with the patient in the upright sitting position, is a diagnostic maneuver for horizontal canal-benign paroxysmal positional vertigo (HC-BPPV). This study is designed to determine whether UHRT, compared to supine head roll test (SHRT), can more accurately diagnose HC-BPPV and determine the subtype of HC-BPPV.Subjects and Method A total of 455 video nystagmus tests performed between April 2019 to June 2021 were retrospectively reviewed, and 63 patients with direction-changing positional nystagmus at UHRT or SHRT were enrolled in this study. UHRT result was classified as negative (if no nystagmus was observed), positive incomplete (if nystagmus was detected in one side), and positive complete (if nystagmus was evoked in both side). The frequency of nystagmus is also included in our assessment. In addition, the results of 4 patients with bow and lean test (BLT) records on videonystagmography were also analysed.Results The concordance rate between UHRT and SHRT was 97.8%, and the positive concordance rate was 91.38%. UHRT and SHRT provided identical subtype diagnosis in 98.1% (52 of 53 cases). In one case, UHRT and SHRT showed opposite results. Evaluating the affected side with bow and lean records, the SHRT, UHRT and BLT showed consistent results. The mean frequency of nystagmus was faster in SHRT than in UHRT.Conclusion UHRT showed equivalent results to SHRT in distinguishing subtype of HC-BPPV. UHRT is a useful method in diagnosing HC-BPPV simply in a sitting position.

Dynamics of functional changes in the spinal column in scoliosis in children in the use of adaptive physical activity techniques

Objective . To evaluate the effectiveness of spinal correction in scoliosis in children in the process of adaptive physical activity (APA). Materials and methods . A study conducted at the Republican Research Center for Radiation Medicine and Human Ecology involved 60 children with scoliosis of varying severity. A course of spinal correction by APA means, forms, and techniques was performed. Results . The conducted study on the use of the scoliosis correction course has showed the effectiveness of the applied means and techniques. It has been proved that children undergoing the developed course in contrast to children undergoing the generally accepted course, reveal a significant improvement in almost all indicators of the positions of the spinal column, namely: lateral deviation of the spine axis (p=0.028), thoracic kyphosis (p&lt;0.001), pelvic tilt (p=0.049), rotation of the left superficial plane (p=0.045). At the trend level, an improvement in the following indicators was noted: lumbar lordosis (p=0.086), rotation of the right superficial plane (p=0.064), lateral deviation to the right (p=0.096). Conclusion . It has been proved that the performed spinal correction course in children with scoliosis in the process of APA is effective.

Where is mirror invariance? Masked priming effects by mirrored and rotated transformations of reversible and nonreversible letters

The cognitive mechanism underpinning mirror priming effects for letters (e.g., IDEA primed by ibea) is still unclear: it could be about mirror invariance (perceptual equivalence of mirror images - d and b - which does not extend to other orientation contrasts like plane rotations - d and p) or about visual similarity (b, d, and p share the same visual features and shape). To enlighten it and investigate the modulatory role of task and orthographic context (words vs single letters), we manipulated letter (nonreversible; reversible) and prime condition (identity, mirrored, rotated, control) in four masked priming experiments: lexical decision with conventional and sandwich paradigms (Experiments 1 and 2), same-different task on words and single letters (Experiments 3 and 4). All experiments replicated the differential mirror priming effect: inhibitory for reversible letters, facilitatory for nonreversible letters. Notably, similar priming effects were found for plane rotations. Regardless of task or orthographic context, a reliably larger orientation cost was found for reversible than nonreversible letters for both mirror images and plane rotations. These results suggest that the underlying mechanism is not mirror invariance, but rather visual similarity allied with prelexical dynamics.

Layer III pyramidal cells in the prefrontal cortex reveal morphological changes in subjects with depression, schizophrenia, and suicide

Brodmann Area 46 (BA46) has long been regarded as a hotspot of disease pathology in individuals with schizophrenia (SCH) and major depressive disorder (MDD). Pyramidal neurons in layer III of the Brodmann Area 46 (BA46) project to other cortical regions and play a fundamental role in corticocortical and thalamocortical circuits. The AutoCUTS-LM pipeline was used to study the 3-dimensional structural morphology and spatial organization of pyramidal cells. Using quantitative light microscopy, we used stereology to calculate the entire volume of layer III in BA46 and the total number and density of pyramidal cells. Volume tensors estimated by the planar rotator quantified the volume, shape, and nucleus displacement of pyramidal cells. All of these assessments were carried out in four groups of subjects: controls (C, n = 10), SCH (n = 10), MDD (n = 8), and suicide subjects with a history of depression (SU, n = 11). SCH subjects had a significantly lower somal volume, total number, and density of pyramidal neurons when compared to C and tended to show a volume reduction in layer III of BA46. When comparing MDD subjects with C, the measured parameters were inclined to follow SCH, although there was only a significant reduction in pyramidal total cell number. While no morphometric differences were observed between SU and MDD, SU had a significantly higher total number of pyramidal cells and nucleus displacement than SCH. Finally, no differences in the spatial organization of pyramidal cells were found among groups. These results suggest that despite significant morphological alterations in layer III of BA46, which may impair prefrontal connections in people with SCH and MDD, the spatial organization of pyramidal cells remains the same across the four groups and suggests no defects in neuronal migration. The increased understanding of pyramidal cell biology may provide the cellular basis for symptoms and neuroimaging observations in SCH and MDD patients.

Effects of Occlusal Plane Inclination on the Temporomandibular Joint Stress Distribution: A Three-Dimensional Finite Element Analysis.

Background Sudden changes in masticatory loads and occlusal conditions contribute to temporomandibular disorders. Clockwise (CW) or counterclockwise (CCW) rotation of the occlusal plane is one of the factors that alter the direction of the occlusal forces transmitted to the temporomandibular joint structures. Finite element analysis was used to identify possible regions of high stress in the temporomandibular joint. Materials and Methods A computer-aided design model of a symmetrical edentulous maxillomandibular bony complex with a temporomandibular joint was manually generated using Rhinoceros 4.0 freeform modeling software. Three-dimensional discrete mesh generation was performed using VRMesh Studio. The reference occlusal plane angle was accepted as 8° in the sagittal plane, and by modifying 4° in the CW and CCW directions, CW and CCW models were obtained, respectively. The present study aimed to evaluate the changes in stress distribution in the condylar cartilage and temporomandibular disc using the von Mises and maximum-minimum principal stress evaluations of three different occlusal plane inclinations. The null hypothesis of this three-dimensional finite element analysis was that “occlusal plane inclination does not change the stress distribution on the temporomandibular joint structures.” Results The compressive stress on the condyle increased with CW rotation of the occlusal plane. The von Mises equivalent stress of the temporomandibular disc shifted to the medial, posterior, and superior directions after CW and CCW rotations of the occlusal plane. The CW rotation of the occlusal plane increased the von Mises equivalent.

Formation of Two-Color Radiation with Controlled Rotation of the Polarization Plane

Formation of Two-Color Radiation with Controlled Rotation of the Polarization Plane

Magnetodielectric effect and significant magnetoelectric coupling of Co3NiNb2O9 single crystal

A4B2O9 (A = Co, Fe, Mn, Ni, B = Nb, Ta) compounds with a corundum-type structure can host multiferroic phenomena and present magnetoelectric coupling to achieve manipulations of their ground states by external fields. High quality Ni-doped Co4Nb2O9 single crystals of Co3NiNb2O9 have been synthesized for the first time using optical floating zone technique. Co3NiNb2O9 exhibits an antiferromagnetic order at 32 K with an easy magnetization axis in the ab plane. Field-dependent magnetizations at 20 K along [100] and [120] directions have a slope change at 6 and 9 kOe, respectively, indicating a spin-flop transition or spin rotation in the ab plane. Temperature dependence of dielectric constants along [100] and [120] directions show a magnetic-field-induced peak near the antiferromagnetic transition, proving a sizable magnetodielectric effect. Pyroelectric currents along [100] and [120] directions also have a divergent behavior near the transition under magnetic fields, manifesting a magnetoelectric coupling effect. The electric polarization along [120] direction reaches 128 μC/m2 under a magnetic field of 40 kOe, larger than that in most phases of the A4B2O9 system.