Horizontal Oblique Research Articles

A Ground Penetrating Radar Array Antenna Designed for Small Targets Detection

Abstract The detection of small targets, especially those made of non-metallic materials, presents significant challenges due to their small size and the difficulty of being detected by traditional metal detectors. Additionally, environmental factors and soil conditions further complicate their detection. Traditional Ground Penetrating Radar (GPR) operate with a single-line detection method, resulting in a low number of scan lines and inefficient detection. This approach makes it difficult to generate slice images and can lead to high missed detection. A miniaturized GPR array antenna suitable for handheld and unmanned platforms has been developed. Utilizing a planar dipole antenna with multiple resistive and capacitive loading, a horizontal oblique polarization array comprising five transmitters and six receivers has been constructed, achieving dual-reception from a single transmission across ten channels, significantly improving upon the limitations of single antenna systems in terms of data volume and sampling interval. Experimental tests demonstrate that the designed system can successfully detect the echo signals of metallic and non-metallic small targets like buried up to 20 cm deep in typical soil conditions, and generate clear slice images, proving its capability for high-resolution imaging detection of shallow buried small targets.

Management of Oblique Root Fracture Using Mineral Trioxide Aggregate: A Case Report

Management of Oblique Root Fracture Using Mineral Trioxide Aggregate: A Case Report

Biomechanical Comparison of Different Volar Screw Placements for Horizontal Oblique Scaphoid Fractures

Recently, some surgeons reported that most scaphoid waist fractures were horizontal oblique and not transverse in orientation. Therefore, this cadaveric study aimed to biomechanically compare fixation strength between central and eccentric screw placements for the volar fixation of this most common scaphoid waist fracture. Eight matched pairs of fresh-frozen forearm cadaver specimens were prepared for testing and randomly assigned to two groups: group I specimens were fixed by screws in a central placement, and group II specimens were fixed by screws in an eccentric placement. Horizontal oblique osteotomy was performed along the scaphoid waist. Then, each specimen was placed under the increasing load of a pneumatically driven plunger. We recorded stiffness, load to failure, and failure mechanisms between the central and eccentric screw placement groups. Stiffness was higher in central screw placement (74.1 N/mm) than in eccentric screw placement (29.39 N/mm). The median loads to failure in groups I and II were 54.14 and 26.22 N, respectively. In this biomechanical model, we demonstrated that central screw placement is superior to eccentric placement in terms of fixation strength. However, further clinical investigation is warranted to evaluate whether the different screw placements for volar approach of horizontal oblique scaphoid fractures affect the clinical outcomes.

Age-dependent changes in pediatric scaphoid fracture pattern on radiographs.

To systematically investigate age-dependent changes in scaphoid fracture prevalence and fracture patterns on radiographs in children under 15years of age. This retrospective study included children with scaphoid fractures, who underwent radiographic examinations between May 1, 2009, and August 31, 2019. Blinded to outcome, all radiographs were reviewed to determine fracture visibility on initial radiographs; to characterize fracture location (distal corner, distal, mid, and proximal body) and orientation (horizontal oblique, transverse, and vertical oblique); and to identify the presence or absence of gap, displacement, and concomitant fractures. Demographic information and information on weight and height were collected. Mann-Whitney U, Kruskal-Wallis rank sum, chi-square, and post hoc tests were used to investigate associations between age, fracture characteristics, and BMI percentile. The study included 180 children (134 boys and 46 girls; 12.3 ± 1.4years) with 59 (33%) distal corner, 42 (23%) distal, 76 (42%) mid, and 3 (2%) proximal body fractures. Younger children were more likely to present with distal corner and distal body fractures while older children with mid and proximal body fractures (p= 0.035). No association was found between age and fracture visibility (p= 0.246), fracture orientation (p= 0.752), presence of gap (p= 0.130), displacement (p= 0.403), or concomitant fractures (p= 0.588). Younger children with scaphoid fractures were more likely to be obese (n= 117; p= 0.038). Scaphoid fractures of the distal corner and distal body were significantly more common in younger children, who are more likely to be obese.

Approach to the Perpendicular Fixation of a Scaphoid Waist Fracture—A Computer Analyzed Cadaver Model

In scaphoid fracture screw fixation, the screw is commonly placed along the long axis of the bone, without consideration of the fracture plane. This position is not perpendicular to transverse waist fractures or to the more common horizontal oblique fractures. Our aim was to examine the feasibility and describe possible approaches to, placing a screw perpendicular and in the center of the scaphoid waist fracture. Computed tomography of 12 cadaver wrists was performed in 3 positions to examine possible approaches in flexion, neutral, and extension of the wrist. The scans were evaluated using a 3-dimensional model that simulated horizontal oblique (60°) and transverse (90°) fractures. We examined all possible approaches for screw positioning and their deviation from the axis perpendicular to the fracture and in the center of its plane. The preferred approaches for a perpendicular screw in a horizontal oblique fracture were found to be proximal-dorsal in flexion or transtrapezial in the extended or neutral positions (through the volar-radial trapezium). In transverse fractures, the possible approaches were proximal-dorsal or transtrapezial in the flexed or neutral positions and distal in the extended position (volar to volar-radial trapezium). In these approaches, the screw could be placed perpendicularly (deviating by < 10°) and in the center of the fracture in all specimens. According to this model, it appears feasible to place a perpendicular screw in thecenter of a horizontal oblique waist fracture using a proximal-dorsal approach in flexion ora transtrapezial approach in neutral or extension positions of the wrist. Palpable landmarksmay be used as additional guides to direct these approaches according to the clinical setting. Perpendicular screw fixation of horizontal oblique or transverse scaphoid waist fractures is a possible option, if chosen for its biomechanical advantages.

Scaphoid Fracture Patterns-Part One: Three-Dimensional Computed Tomography Analysis.

Objective Using three-dimensional (3D) computed tomography models of acute scaphoid fractures, we looked for differences between volumetric size of the fracture fragments, recognizable groups, or a shared common fracture area. Methods We studied 51 patients with an adequate computed tomography scan of an acute scaphoid fracture using 3D modeling. Fracture surfaces were identified and fragment volumetric size of the fracture fragments was measured. A principal component analysis was used to find groups. Density mapping was used to image probable common fracture areas in the scaphoid. Results Forty-nine of 51 fractures had a similar pattern. It was not possible to identify subgroups based on fracture pattern. The mean volumetric size of the fracture fragments of the proximal (1.45 cm 3 ± 0.49 cm 3 standard deviation [SD]) and distal fracture fragments (1.53 cm 3 ± 0.48 cm 3 SD) was similar. There was a single common fracture area in the middle third of the bone. In the distal third, there were no horizontal fractures through-but only directly proximal to-the tubercle suggesting that these would be best classified as distal waist fractures. Conclusion Acute scaphoid fractures mainly occur in the middle third of the bone and tend to divide the scaphoid in half by volumetric size of the fracture fragments. There were two distinct grouping patterns: fractures through the proximal and middle third were horizontal oblique, whereas fractures of the distal third were vertical oblique. It seems that scaphoid fractures might be classified into proximal pole fractures, a range of waist fractures, and tubercle avulsion fractures. Level of evidence This is a Level IV study.

Vertical Lasso and Horizontal Lasso Sutures for Repair of Horizontal Cleavage and Horizontal Oblique Meniscal Tears: Surgical Technique and Indications

Horizontal cleavage and horizontal oblique meniscal tears have traditionally been treated with partial meniscectomy. Recent research has shown the deleterious long-term effects of meniscectomy in these patients regarding the development of osteoarthritis. Meniscal preservation is thus the preferred method of surgical treatment in patients with these tears. However, traditional repair techniques using inside-out sutures or suture anchor–based devices do not address the horizontally aligned nature of these particular tears and thus do not compress the meniscal tissue in the correct plane. The recent development of an arthroscopic suture-passing system now allows surgeons to place arthroscopic sutures in any pattern or direction. This allows surgeons to treat tears of any type with sutures ideally placed to repair the given tears. This Technical Note describes and demonstrates 2 all-suture, all-inside, arthroscopic meniscus repair techniques to treat these challenging horizontal tear types. The repair techniques are named the vertical lasso and horizontal lasso.

3-Dimensional Analysis of Scaphoid Fracture Angle Morphology

Scaphoid fractures are classified according to their 2-dimensional radiographic appearance, and transverse waist fractures are considered the most common. Our hypothesis was that most scaphoid fractures are not perpendicular to the longitudinal axis of the scaphoid (ie, not transverse). Computerized 3-dimensional analyses were performed on 124 computed tomography scans of acute scaphoid fractures. Thirty of the fractures were displaced and virtually reduced. The angle between the scaphoid's first principal axis (longitudinal axis) and the fracture plane was analyzed for location and displacement. The distal radius articular surface was used to depict the volar-dorsal vector of the wrist. There were 86 fractures of the waist, 13 of the distal third, and 25 of the proximal third. The average angle between the scaphoid longitudinal axis and the fracture plane was 53° for all fractures and 56° for waist fractures, both differing significantly from a 90°, transverse fracture. The majority of fracture planes were found to have a volar distal to dorsal proximal (horizontal oblique) inclination relative to the volar-dorsal vector. Most waist fractures were horizontal oblique and not transverse. According to these findings, fixation of all fractures along the longitudinal axis of the scaphoid may not be the optimal mode of fixation for most. A different approach may be needed in accordance with the fracture plane. Diagnostic II.

Analysis on Shift of Nature Modes of Liquid Sloshing in a 3D Tank Subjected to Oblique Horizontal Ground Motions with Damping Devices

The extended study of Wu et al. (2012) of sloshing fluid in tanks with internal structures from 2D to 3D is presented in the paper. The phenomenon of liquid sloshing in a 3D tank with various damping devices is solved by the time-independent finite difference method combined with the ghost (fictitious) cell approach. Two types of damping devices, a tank bottom-mounted baffle and a vertically surface-piercing plate, are considered in the study. In this work, the experimental measurement of liquid sloshing in a 3D tank with the baffle is carried out to further validate the present simulation. The comparison of the results between the experimental measurement and the present computation shows good accuracy. The effect of the vertically tank bottom-mounted baffle or the vertically surface-piercing plate on various sloshing waves for the tank under horizontal oblique excitation is discussed and investigated. The phenomena of the shift of the nature frequency of the tank with damping devices due to various oblique horizontal excitations under different sloshing waves are presented in detail. The sloshing wave type is varied due to the influence of the baffle or the plate, and the coexistence of two types of sloshing waves is found for the tank under larger excitation frequencies.

The Evaluation of Three Electronic Apex Locators in Teeth with Simulated Horizontal Oblique Root Fractures

ABSTRACT Aim The accuracy of three electronic apex locators (EALs) to locate the apical limit in teeth with simulated horizontal oblique root fractures was investigated. Material and Methods A horizontal oblique incomplete root fracture was simulated on 30 freshly extracted maxillary anterior teeth by means of a notch made on the vestibular root plane 8 mm from the anatomic apex. The EALs investigated were the ProPex II (Dentsply Maillefer, Ballaigues, Switzerland), the Mini Apex Locator (Sybron Endo, Orange CA), and the Dentaport ZX (J. Morita Corp, Kyoto, Japan). The electronic measurements were compared with the real “working length.” Results The accuracy obtained was Dentaport ZX in 66.66% (n=20), the Mini Apex Locator in 63.33% (n=4) and the Propex II in 53.34% (n=4). The analysis of variance and chi-square test showed no statistical significant differences between Propex and Dentaport ZX EALs (Elecronic Apex Locators) at 0.5 mm and 1.0 mm tolerance levels. These results suggest that electronic apex locators can effectively and reproducibly detect oblique root fractures. Conclusion Although Propex II apex locator was not able to determine the working length accurately, but Dentaport ZX and Mini Apex Locator were able to determine the working length within acceptable range.

The Evaluation of Four Electronic Apex Locators in Teeth with Simulated Horizontal Oblique Root Fractures

The accuracy of four electronic apex locators (EALs) to locate the apical limit in teeth with simulated horizontal oblique root fractures was investigated. A horizontal oblique incomplete root fracture was simulated on 20 freshly extracted maxillary anterior teeth by means of a notch made on the vestibular root plane 8 mm from the anatomic apex. The EALs investigated were the ProPex (Dentsply Maillefer, Ballaigues, Switzerland), the NovApex (Forum Technologies, Rishon Le-Zion, Israel), the Root ZX (J. Morita Corp, Kyoto, Japan), and the Elements Apex Locator (SybronEndo, Orange CA). The electronic measurements were compared with the real “working length.” The accuracy obtained was of 80% ( n = 16) and 95% ( n = 19) with the ProPex, 70% ( n = 14) and 95% ( n = 19) with the NovApex, 60% ( n = 12) and 90% ( n = 18) with the Root ZX, and 60% ( n = 12) and 85% ( n = 17) with the Elements Apex Locator when tolerances of 0.5-mm and 1.0-mm tolerance were, respectively, allowed. The analysis of variance (p > 0.05) and chi-square test (0.5 mm/p = 0.47 and 1.0 mm/p = 0.63 tolerances) showed no statistical significant differences between the EALs at either tolerance level.

Fracture of the carpal scaphoid: Frequency and distribution in a well-defined population

The incidence, location, and type of scaphoid fractures found in a well-defined population is described. Fractures of the carpal scaphoid ( n = 442) were identified during an eight-year period, of which 19 (5%) were nonunions. At the initial radiographic examination the fractures were visible on PA views in 70% of the cases (true lateral 10%, scaphoid view neutral 77%, scaphoid view ulnar deviated 73%, and scaphoid view with the X-ray tube tilted 30° distally 71%). Among inhabitants living in the Odense Municipality (population at risk 170648 in 1983 to 174948 in 1989) 222 males and 51 females (age range 9–87 year) sustaining scaphoid fractures during a seven-year were period used for computation of incidences. During the survey, there was an average annual incidence of scaphoid fracture of 8 per 100000 females, and 38 per 100000 males. All patients (except a 9-year-old male) were aged 10 years or over. In the age-group 10–14 years there was an average annual incidence of 3 per 100000 females, and 39 per 100000 males. Average annual incidence per 100000 inhabitants of carpal scaphoid fractures according to the location was proximal 6, middle 15, and distal (fractures of the tuberosity included) 2. Average annual incidence per 100000 inhabitants of carpal scaphoid fractures according to type was transverse 7, horizontal oblique 9, vertical oblique 1, avulsion/fracture of the tuberosity 5, and not stated 1.