Compensation trends of the angulation of first molars:retrospective study of 1403 malocclusion cases

We investigated the compensatory trends of mesiodistal angulation of first molars in malocclusion cases. We compared differences in the angulation of first molars in different developmental stages, malocclusion classifications and skeletal patterns. The medical records and lateral cephalogrammes of 1 403 malocclusion cases taken before treatment were measured to evaluate compensation of molar angulation in relation to the skeletal jaw. The cases were stratified by age, Angle classification and skeletal patterns. Differences in the mesiodistal angulation of the first molars were compared among the stratifications. We observed three main phenomena. First,angulation of the upper first molar varied significantly with age and tipped most distally in cases aged,12 years and least distally in cases aged.16 years. The lower first molar did not show such differences. Second, in Angle Class II or skeletal Class II cases, the upper first molar was the most distally tipped, the lower first molar was the most mesially tipped, and opposite angulation compensation was observed in Class III cases. Third, in high-angle cases, the upper and lower first molars were the most distally tipped, and opposite angulation compensation was observed in low-angle cases. These data suggest that the angulation of the molars compensated for various growth patterns and malocclusion types. Hence, awareness of molar angulation compensation would help to adjust occlusal relationships, control anchorage and increase the chances of long-term stability.

Recurrence of choledocholithiasis following endoscopic bile duct clearance: Long term results and factors associated with recurrent bile duct stones

AIMTo evaluate the rate of recurrence of symptomatic choledocholithiasis and identify factors associated with the recurrence of bile duct stones in patients who underwent endoscopic retrograde cholangiopancreatography (ERCP) and endoscopic sphincterotomy (EST) for bile duct stone disease. METHODSAll patients who underwent ERCP and EST for bile duct stone disease and had their bile duct cleared from 1/1/2005 until 31/12/2008 was enrolled. All symptomatic recurrences during the study period (until 31/12/2015) were recorded. Clinical and laboratory data potentially associated with common bile duct (CBD) stone recurrence were retrospectively retrieved from patients’ files. RESULTSA total of 495 patients were included. Sixty seven (67) out of 495 patients (13.5%) presented with recurrent symptomatic choledocholithiasis after 35.28 ± 16.9 mo while twenty two (22) of these patients (32.8%) experienced a second recurrence after 35.19 ± 23.2 mo. Factors associated with recurrence were size (diameter) of the largest CBD stone found at first presentation (10.2 ± 6.9 mm vs 7.2 ± 4.1 mm, P = 0.024), diameter of the CBD at the first examination (15.5 ± 6.3 mm vs 12.0 ± 4.6 mm, P = 0.005), use of mechanical lithotripsy (ML) (P = 0.04) and presence of difficult lithiasis (P = 0.04). Periampullary diverticula showed a trend towards significance (P = 0.066). On the contrary, number of stones, angulation of the CBD, number of ERCP sessions required to clear the CBD at first presentation, more than one ERCP session needed to clear the bile duct initially and a gallbladder in situ did not influence recurrence. CONCLUSIONBile duct stone recurrence is a possible late complication following endoscopic stone extraction and CBD clearance. It appears to be associated with anatomical parameters (CBD diameter) and stone characteristics (stone size, use of ML, difficult lithiasis) at first presentation.

Glycogen content relative to expression of glycogen phosphorylase(GPH) and hexokinase(HK) during the reproductive cycle in the Fujian Oyster, Crassostrea angulata

Glycogen, a polymer of glucose, is an important means of storing energy. It is degraded by glycogen phosphorylase （GPH） and hexokinase （HK）, glycogen phosphorylase, and hexokinase cDNAs （Ca-GPH and Ca- HK, respectively）, which encode the primary enzymes involved in glycogen use, cloned and characterized and used to investigate the regulation of glycogen metabolism at the mRNA level in Crassostrea angulata. Their expression profiles were examined in different tissues and during different reproductive stages. Full-length cDNA of GPHwas 3 078 bp in length with a 2 607 bp open reading frame （ORF） predicted to encode a protein of 868 amino acids （aa）. The full-length HK cDNA was 3 088 bp long, with an ORF of 1 433 bp, predicted to encode a protein of 505 aa. Expression levels of both genes were found to be significantly higher in the gonads and adductor muscle than in the mantle, gill, and visceral mass. They were especially high in the adductor muscle, which suggested that these oysters can use glycogen to produce a readily available supply of glucose to support adductor muscle activity. The regulation of both genes was also found to be correlated with glycogen content via qRT-PCR and in situ hybridization and was dependent upon the stage of the reproductive cycle （initiation, maturation, ripeness）. In this way, it appears that the expression of Ca-GPH and Ca-HK is driven by the reproductive cycle of the oyster, reflecting the central role played by glycogen in energy use and gametogenic development in C. angulata. It is here suggested that Ca- GPH and Ca-HK can be used as useful molecular markers for identifying the stages of glycogen metabolism and reproduction in C. angulata.

Study of coronary sinus anatomy during levophase of coronary angiography

BACKGROUND Coronary sinus(CS)imaging has recently gained importance due to increasing need for mapping and ablation of electrophysiological arrhythmias and left ventricular(LV)pacing during cardiac resynchronization therapy(CRT).Retrograde venogram is the current standard for imaging CS and its tributaries.AIM To evaluate CS anatomy during levophase of routine coronary angiography to aid LV lead implantation during CRT.METHODS In this prospective observational study,164 patients undergoing routine coronary angiography for various indications(Chronic stable angina-44.5%,acute coronary syndrome-39.5%,Dilated cardiomyopathy-11%,atypical chest pain-5%)were included.Venous phase(levophase)of left coronary injection was recorded in left anterior oblique-cranial and right anterior oblique-cranial views.Visibility of coronary veins,width and shape of CS ostium,angulations of proximal CS with body of CS were noted.Presence,size,take-off angle and tortuosity of posterolateral vein(PLV),anterior interventricular veins(AIV)and middle cardiac vein(MCV)were also noted.RESULTS During levophase,visibility grade(Muhlenbruch grade)for coronary veins was 3 in 74%and 2 in 26%of cases.Visibility of CS did not correlate with body mass index.The diameter of CS ostium was<10 mm,10-15 mm and>15 mm in 48%,42%and 10%of patients respectively.Proximal CS was tubular in 136(83%)patients and funnel-shaped in 28(17%)patients.Sharp take-off angulation between ostium and body of CS was seen in 16(10%)patients.Two or more PLV were present in 8 patients while PLV was absent in 52(32%)patients.Angle of take-off of PLV with body of CS was favourable(0°-45°)in 65(40%)patients.The angle was 45°-90°in 36 patients and difficult take-off angle(>90°)was seen in 8 patients.Length of PLV reached distal third of myocardium in 84 cases and middle third in 11 cases.There was no tortuosity in 79 cases,a single bend in 29 cases and more than 2 bends in 4 cases.Thirty nine(24%)patients had other veins supplying posterior/Lateral wall of LV.There was a single vein supplying lateral/posterior wall in 31(19%)patients.Diameter of MCV and AIV was significantly larger in patients with absent PLV as compared to patients with a PLV.CONCLUSION Levophase study of left coronary injection is effective in visualization of the CS in almost all patients undergoing coronary angiography and may be an effective alternative to retrograde venogram in patients with LV dysfunction or LBBB.

Changes in the crown angulation and dental arch widths after nonextraction orthodontic treatment: Model analysis of mild crowding with high canines

This study was undertaken to examine which factors contributed to the correction of crowding in two patients who underwent nonextraction orthodontic treatment. A study model analysis was conducted to determine the effects of the orthodontic treatment for crowding with high canines on crown angulation and dental arch width in two patients. The results showed that the crown angulation was significantly increased, indicating distal tipping in the maxillary dental arch. This tendency was most commonly observed in the premolars among the lateral teeth. With respect to the dental arch width, the largest change was evident in the first molar and first premolar regions in cases 1 and 2, respectively. On the basis of these results, up-righting of mesially tipped lateral teeth and expansion of narrow dental arches could prove to be the keys to the success of space regaining or correction of high canines and mild crowding.

The Precise Methods for the Measurement of Collimator Hole Angulation and Center of Rotation of SPECT by Adaptive Quality Control Phantom

The Adaptive Quality Control Phantom (AQCP) is a computer-controlled phantom which positions and moves a radioactive source in the Field of View (FOV) of an imaging nuclear medicine device on a definite path to produce a spatial distribution of gamma rays to perform QC Tests such as the Collimator Hole Angulation (CHA) and the Center of Rotation (COR) of Single Photon Emission Computer Tomography (SPECT). The collimator hole angulation for six collimators was measured using a point source and a computer-controlled cylindrical positioning system. In this method, the displacement of the image of a point source was examined as the AQCP was moving point source vertically away from the collimator face. The results of the high-accuracy measurement method of CHA show that the measurement accuracy for absolute angulation errors is better than ±0.024°. The Root Mean Square (RMS) of CHA for LEHR, LEHS and LEUHR collimators of SMV dual heads camera and LEGP, MEGP and HEGP of GE Millennium MG were evaluated to be 0.290°, 0.292°, 0.208°, 0.154°, 0.220° and 0.202°, respectively. It is to be added in this connection that the evaluated RMS of CHA for LEHR collimator with the distance variation from the collimator’s surface ±1 mm has been varied ±0.04 degree. A new method for the center of rotation assessment by AQCP is introduced and the results of this proposed method as compared with the routine QC test and their differences are discussed in detail. We defined and measured a new parameter called Dynamic Mechanical Error (DME) for applying the gantry motion correction.

The Performance of a Novel Latching-Type Electromagnetic Actuator for Single-Port Laparoscopic Surgery

This paper reports on the performance evaluation of a novel latching-type electromagnetic actuator which is designed to be embedded at selected joints along single-port laparoscopic surgical instruments (SLS). The aim of this actuator is to allow these instruments to become articulated with a push of a button in order to provide the optimum angulation required during SLS operations. This new actuator is comprised of electromagnetic coil elements, soft magnetic frames and a permanent magnet. Unlike conventional electromagnetic actuators, latching-type electromagnetic actuators could maintain their positions at either end of the actuation stroke without any power application requirement. In the current design, magnetic attraction forces initiated between the permanent magnet and the magnetic frame are utilised to lock the position of the actuator whilst a certain angulation position of the actuator is achieved as a result of the magnetic repulsion forces established between the permanent magnet and the coil elements. The performance of the new actuator in terms of the output force, maximum angulation and patient’s safety, was evaluated experimentally and the results were found to compare well with those acquired numerically using finite element methods. This actuator was seen to exhibit sufficient actuation forces and hence, it was capable of providing adaptable angulation characteristics for SLS tools. Finally, thermal evaluation of the actuator’s operation was conducted, which was found to be within safety limits specified by clinicians.

Predictors of angle widening after laser iridotomy in Chinese patients with primary angle-closure suspect using ultrasound biomicroscopy

AIM:To assess the predictive value of baseline parameters of ultrasound biomicroscopy(UBM) for angle widening after prophylactic laser peripheral iridotomy(LPI) in patients with primary angle-closure suspect(PACS).METHODS:Angle-opening distance(AOD),trabecular iris angle(TIA),iris thickness,trabecular-ciliary process angle,and trabecular-ciliary process distance were measured using UBM performed before and two weeks after LPI.Iris convexity(IC),iris insertion,angulation,and ciliary body(CB) size and position were graded.Uni-and multivariate regression analyses were used to determine factors predicting the change in AOD(ΔAOD500,calculated as an angle width change before and after LPI) in all quadrants and in subgroup quadrants based on IC.RESULTS:In 94 eyes of 94 patients with PACS,LPI led to angle widening with increases in AOD500 and TIA(P<0.01).Multivariable regression analysis showed that IC(P<0.001),CB position(P=0.007) and iris insertion(P=0.049) were significantly predictive for ΔAOD500.All quadrants were categorized into extreme IC(27.8%),moderate IC(62.3%),and absent IC(9.9%) subgroups.The AOD500 increased by 220% and no other predictive factor was found in the extreme IC quadrants.The AOD500 increased by 55%,and baseline iris angulation was predictive for smaller changes in ΔAOD500 in the moderate IC quadrants.CONCLUSION:In PACS patients,quadrants with greater iris bowing predict substantial angle widening after LPI.Quadrants with a flatter iris,anteriorly positioned CB,and basal iris insertion are associated with less angle widening after LPI.Quadrants with iris angulation as well as a flatter iris configuration predict a smaller angle change after LPI.

Mesially Directed Inclination of Posterior Teeth Contributing to Maxillary High Canine, and Changes during Orthodontic Treatment

Objective: The aim of study was to evaluate the nature of mesiodistal angulation of the posterior teeth in patients with maxillary high canine, and to identify possible associations of crowding with mesial axial angulation of the maxillary posterior teeth. Methods: The present study included seven Japanese male and 23 Japanese female patients. Study models were analyzed to evaluate the effectiveness of orthodontic treatment. A protractor was used to measure crown angulations, which were measured with reference to the posterior angle between the functional occlusal plane (FOP) and the long axis of the clinical crown of the lateral teeth and first molars. A sliding digital caliper was used to measure dental arch widths. Changes in the rotation of the maxillary molars were analyzed using “occlu-sograms”, which were printed from photographs of the occlusal aspect of the study model. Results: The maxillary teeth interacted with one another in the alveolar bone, resulting in progressive mesial tipping of the posterior teeth before orthodontic treatment. After orthodontic treatment, the angle relative to the FOP exhibited a significant increase, indicating that the maxillary teeth underwent distally directed uprighting (P P Conclusions: Based on the results, both uprighting of mesially tipped lateral teeth and expansion of narrow dental arches could prove to be keys to success in space regaining or correction of high canines and mild crowding.

Results of the Measurement of the Collimator Hole Angulation for Different Collimators of SPECT with Adaptive Quality Control Phantom

The Adaptive Quality Control Phantom (AQCP) is the computer-controlled phantom which positions and moves a radioactive source in the Field of View (FOV) of an imaging nuclear medicine device on a definite path to produce any spatial distribution of gamma rays to perform the QC Tests such as the Collimator Hole Angulation (CHA) of Single Photon Emission Computer Tomography (SPECT). The collimator hole angulation for seven collimators were measured with the method by using a point source and computer-controlled cylindrical positioning. In this method the displacement of the image of a point source examined as the AQCP move point source vertically away from the collimator face. The results of the high-accuracy measurement method of CHA show that the measurement accuracy for absolute angulation errors is better than ±0.024°. The Root Mean Square (RMS) of CHA for LEHR, LEHS, LEUHR, MEGP-250, MEGP-300, MEGP-360 and HEPH collimators of SMV dual heads camera were measured to be 0.290°, 0.292°, 0.208°, 0.194°, 0.181°, 0.177°, 0.150°, respectively. The Root Mean Square (RMS) of CHA for LEGP, MEGP and HEGP collimators of GE Millennium MG were measured to be 0.154°, 0.220° and 0.202° respectively. It is to be added in this connection that the measured RMS of CHA for LEHR collimator with the distance variation from the collimator’s surface +/– 1 mm has been varied +/– 0.04 degree.

Association between anterior internal fixation systems and post-operative lateral angulation in thoracolumbar fractures

Objective To explore the effects of the anterior internal fixation systems on the post-operative lateral angulation in treatment of thoracolumbar fractures.Methods A retrospective study was done to analyze the 172 patients who had

Mechanical properties of nickel-titanium archwire used in the final treatment phase of Tip-Edge Plus technique： an in vitro study

Background As the only active component in final treatment phase of Tip-Edge Plus technique, the activation of nickel-titanium orthodontic archwires is one of the factors that affect the torque expression. It is necessary to evaluate the mechanical properties of the nickel-titanium wire used in the final treatment phase in simulated oral environments to forecast the treatment outcomes. Methods The mechanical properties of 171 thermal nickel-titanium wires of 0.35 mm （0.014-in） in diameters with different deflection of 40 mm in length were investigated with three-point bending test. The samples were divided into 2 groups： as-received and bended groups. In the bended group, samples were divided into 7 subgroups according to the amounts of deflection and named by the canine angulations （-25~, -19~, -13~, -7~, -1~, ＋5~, ＋11~）. The deflection of wires was made by inserting the wires into the deep tunnel of Tip-Edge Plus brackets positioned in plaster casts with different canine angulations to mimic the use of nickel-titanium wires in the final treatment phase. Immersed the bended group in artificial saliva （pH 6.8） and preserved at 37.0~C. Eight durations of incubation were tested： 1 to 8 weeks. Three analogous samples of each group and subgroups were tested per week. Stiffness （YS：E） and the load-deflection characteristics of unloading plateau section were obtained. Results Significant changes in specific mechanical properties were observed in long-term immersed and large deflected wires compared with as-received groups. Both immersion time and deflection affected the mechanical properties of wires in the simulated oral environment, and the two factors had synergistic effect. In groups -25~, -19~ and -13~, stiffness （YS：E） increased then decreased and average plateau force and ratio of variance decreased then increased correspondingly at specific time. Conclusions In the final treatment phase of Tip-Edge Plus technique, the mechanical properties of nickel-titanium wire are associated with the using time and amounts of deflection and it may affect treatment outcomes. As the main reason for wire deflection, canine crown angulation plays an important role in the wire performance. It may be wise to focus on the canine crown angulations and using time in clinic with Tip-Edge Plus technique and make proper adjustment to help to make sure the treatment outcomes.

Influence of severe neck angulation on hemodynamic and clinical outcomes following endovascular aneurysm repair:a hemodynamic analysis and a retrospective cohort study

Background: For patients with severe neck angulation (SNA), hemodynamic and clinical outcomes following endovascular aneurysm repair (EVAR) are still unclear. This study aimed to explore the influence of SNA on hemodynamic and clinical outcomes following EVAR.Methods: This study included a hemodynamic analysis and a retrospective cohort study from West China Hospital of Sichuan University between January 2011 and December 2020. The Cox regression model, inverse probability of treatment weighting (IPTW) analysis, sensitivity analysis, and subgroup analysis were applied. Primary outcome was type IA endoleak (T1AEL).Results: In this hemodynamic analysis, nine non-severe neck angulation (nSNA) and 16 SNA idealized models were constructed. We found a significant difference in drag force between SNA and nSNA models (7.016 ± 2.579 Nvs. 4.283 ± 1.460 N,P = 0.008), and proximal neck angles were significantly associated with the magnitude of drag force (F = 0.082 ×α-0.006 ×β + 2.818, α: 95% confidence interval [CI] 0.070-0.094;P = 0.001;β: 95% CI -0.019 to 0.007;P = 0.319). In our cohort study, 514 nSNA patients (71.5 ± 8.5 years;459 males) and 208 SNA patients (72.5 ± 7.8 years;135 males) were included, with a median follow-up duration of 34 months (16-63 months). All baseline characteristics were well balanced after IPTW matching. We found that SNA was associated with a significant risk of adverse limb event (hazard ratio [HR] 2.18, 95% CI 1.09-3.12), yet was not associated with T1AEL, overall survival, or reintervention. In patients without proximal or distal additional procedures (DAP), subgroup analyses suggested a significant risk of T1AEL (Proximal: HR 5.25, 95% CI 1.51-18.23;Distal: HR 5.07, 95% CI 1.60-16.07) and adverse limb event (Proximal: HR 2.27, 95% CI 1.01-5.07;Distal: HR 2.91, 95% CI 1.30-6.54) in SNA patients. However, no noticeable difference was observed in patients with proximal or DAP.Conclusions: SNA has a critical influence on hemodynamic and clinical outcomes following EVAR. Appropriate additional procedures may be of great benefit to SNA patients.

Novel method of constructing generalized Hoberman sphere mechanisms based on deployment axes

This study proposes a method of constructing type Ⅱ generalized angulated elements(GAEs Ⅱ)Hoberman sphere mechanisms on the basis of deployment axes that intersect at one point.First,the constraint conditions for inserting n GAEs II into n deployment axes to form a loop are given.The angle constraint conditions of the deployment axes are obtained through a series of linear equations.Second,the connection conditions of two GAEs Ⅱ loops that share a common deployable center are discussed.Third,a flowchart of constructing the generalized Hoberman sphere mechanism on the basis of deployment axes is provided.Finally,four generalized Hoberman sphere mechanisms based on a fully enclosed regular hexahedron,arithmetic sequence axes,orthonormal arithmetic sequence axes,and spiral-like axes are constructed in accordance with the given arrangement of deployment axes that satisfy the constraint conditions to verify the feasibility of the proposed method.