Effect of Preliminary Deformation on Microstructure and Texture of Iron-Chromium Alloy Prepared by Severe Plastic Deformation

The effect of preliminary deformation on the microstructure and texture of iron-chromium alloy prepared by severe plastic deformation (SPD) has been investigated in grain refinement and inhomogeneity structure. Equal channel angular pressing (ECAP) is a well-known SPD process that uses a die channel with a sharp angle. The texture and misorientation map of ECAP processed material was observed electron backscattered diffraction (EBSD) analysis, providing information on structure evolution. The observation was done in the transverse plane from the middle to the sub-surface. The data logger also records the pressure of the ECAP process. The result showed that the sub-surface has a more deformed structure than the middle due to the die channel's sharp angle and shear direction. The texture exhibited a random orientation after the first pass ECAP process. The stacking fault energy and accumulation dislocation are also associated with this process. Several shear bands can be seen clearly, which is parallel to the shear direction. It concluded that the preliminary deformation by ECAP was effective to promote grain refinement due to their high equivalent strain

What are the significant factors affecting pain in patients with Hartofilakidis type Ι developmental dysplasia of the hip?

Objective To explore the influencing factors of age at onset of pain and severe pain in patients with Hartofilakidis type I developmental dysplasia of the hip (DDH). Methods A retrospective study of 83 patients with DDH treated at our hospital from January 2017 to June 2021 was conducted. The age at onset of pain, patients’ demographic data, and radiographic parameters were collected. Multiple linear regression was used to determine the influencing factors of age at onset of pain. Cox regression analysis was used to determine the influencing factors of severe pain attacks. Results According to the results of multiple linear regression analysis, when the distance between the medial femoral head and the ilioischial line increased by one millimetre, the age at onset of pain decreased by 1.7 years (β = − 1.738, 95% CI − 1.914–[− 1.561], p < 0.001). When the sharp angle increases by one degree, the age at onset of pain decreases by 0.3 years (β = − 0.334, 95% CI − 0.496–[− 0.171], p < 0.001). According to the results of the Cox regression analysis, for each additional degree of the lateral centre-edge angle (LCEA), the probability of severe pain was reduced by 5% (Exp [β]: = 0.947, 95% CI 0.898–0.999, p = 0.044). For each additional millimetre in the distance between the medial femoral head and the ilioischial line, the likelihood of severe pain increased by 2.4 times (Exp [β]: 2.417, 95% CI 1.653–3.533, p < 0.001). Conclusion Larger distances between the medial femoral head and the ilioischial line and sharp angle can lead to an earlier age at onset of pain in patients with DDH. Small LCEA and excessive distance between the medial femoral head and the ilioischial line are risk factors for severe pain.

Colonic Stenting Using Side-Viewing Endoscope: A Case Report

Colonic self-expandable metal stents (SEMS) are widely used as palliation for malignant obstruction. The conventional method involves using a forward-viewing endoscope as part of the procedure. Sometimes, however, the sharp angle of the stricture poses difficulty in evaluating the stricture, so a guidewire is placed across the stricture. Here, we present a case where a side-viewing endoscope was employed for colonic stent placement and propose its use in patients with sharp bends to increase success.

Preliminary results of rigid fixation (locking plate/screw) after triple pelvic osteotomy without a hip spica cast: A modified fixation method in 21 patients

Objectives: The aim of this study is to investigate whether rigid fixation after triple pelvic osteotomy (TPO) utilizing a 3.5-mm locking plate and screws without hip spica cast can provide enough stability and prevent correction loss in pediatric patients with developmental dysplasia of the hip (DDH) and Legg-Calvé-Perthes disease (LCPD). Patients and methods: A total of 21 hips of 21 pediatric patients (9 males, 12 females; mean age: 9.3±2.0 years; range, 6 to 14 years) who underwent rigid fixation with locking plate/screws after TPO for DDH and LCPD between June 2015 and October 2018 were retrospectively analyzed. Preoperative, immediate postoperative, and six-month follow-up anteroposterior radiographs were compared for the Wiberg’s center-edge angle (CE), Sharp angle, acetabular coverage of the femoral head (ACFH), and center-head distance discrepancy (CHDD). The patient demographics, surgery time, perioperative complications were evaluated. Results: Underlying diagnosis were DDH in 14 patients and LCPD in seven patients. In patients with DDH, postoperative evaluation showed significant increase in the mean CE angle (5.6±16.1° vs. 30.5±9.3°, respectively) and ACFH (46.4±16.8% vs. 84.5±12.1%, respectively), and a significant decrease in the mean Sharp angle (55.3±6.2° vs. 35.6±7.8°, respectively) and CHDD (14.6±10.7% vs. 6.2±5.6%, respectively). The final follow-up revealed that there was no correction loss in these parameters. In the patients with LCPD, postoperative evaluation showed a significant increase in the mean CE (20.1±11.1° vs. 38.3±9.6°, respectively) and ACFH (62.9±18% vs. 91.4±10.1%, respectively), and a significant decrease in the mean Sharp angle (46±3.6° vs. 25.2±5.5°, respectively). The final follow-up revealed that there was no correction loss in radiological parameters. No perioperative complications were noted. Conclusion: Our study results suggest that rigid fixation construct with a 3.5-mm locking plate and screws without hip spica cast can provide adequate stability to allow early mobilization following TPO in children without any loss of correction, until bony healing at the osteotomy sites.

IMPROVEMENT OF THE STRUCTURAL LAYOUT OF POTATO PLANTERS’ COULTER GROUP

Structural layouts of coulters and their groups in potato planters are justified in the article based on the morphological features of the potato plant, its requirements for growing conditions and ensuring the quality of the planting process. The purpose of coulter groups is to form a bed for placing tubers with a loose layer of soil in 5-8 cm and sealing them with loosened soil to a certain depth. To substantiate the type of potato planter coulters that meet the requirements for potato growing conditions to the maximum extent possible, optimize the parameters of coulter groups that automatically ensure the stability of the coulter travel depth when imitating irregularities of the field microrelief. A comparative analysis of the impact on the soil of the most common anchor coulters with a blunt angle of soil entry and a sharp angle with an individual floating suspension is given, and indicators of the quality of their operation are described. It was found that coulters with an individual floating suspension and an acute angle of soil entry meet the requirements for potato growing conditions to the maximum extent possible. In order to ensure travel stabilization of such a coulter at a given depth when imitating field irregularities, a version of the coulter group has been developed that provides automatic correction of the coulter's angle of attack when changing its travel depth. Experimental studies have optimized the parameters of the coulter suspension that ensure automatic imitation of field microrelief irregularities up to 20 cm deep within the initial requirements for potato planting machines. Coulters with an individual floating suspension and a sharp angle of soil entry most fully meet the requirements for potato growing conditions to the maximum extent possible. A coulter group with a suspension aspect ratio of 150:200:400:400 cm and an acute angle of coulter entry into the soil provides automatic maintenance of the set coulter travel depth within the initial requirements (±2 cm) for irregularities in the field microrelief of up to 200 mm. In this case, the bottom and walls of the furrow are not compacted.

Evolution of Primary and Eutectic Si Phase and Mechanical Properties of Al2O3/Al-20Si Composites under High Pressure

To further improve the mechanical properties of Al-Si alloys. The phase, microstructure and mechanical properties of Al2O3/Al-20Si composites under different pressures were studied. The results show that the phase of Al2O3/Al-20Si composites are composed of α-Al phase, β-Si phase and Al2O3. Under the condition of hot-pressing sintering (0.02 GPa), a large number of Si phases with irregular shape and sharp angle are distributed on the α-Al matrix. Under high pressure solidification, the growth of primary Si phase is inhibited and the eutectic Si is spheroidized obviously. The microhardness of Al2O3/Al-20Si composite increases from 102.5 HV0.05 at 0.02 GPa to 156.4 HV0.05 at 4 GPa, which increases by 52.6%. The compressive strength increased from 381.5 MPa at 0.02 GPa to 469.1 MPa at 4 GPa, increasing by 23%. With the increase of solidification pressure, the fracture mechanism changes from cleavage fracture to quasi cleavage fracture.

Pandanipora fragilis—a new deep-water cyclostome bryozoan from the subequatorial Mid-Atlantic Ridge, Atlantic Ocean, and a review of Pandanipora worldwide

A new cyclostome bryozoan, Pandanipora fragilis n. sp., is described from 3453 m depth on the subequatorial Mid-Atlantic Ridge. It differs from the type species, P. helix Grischenko, Gordon & Melnik, 2018, by a combination of colonial and zooidal characters. These include regular branching of a uniserial stem along the entire colony length; a straight or just slightly elevated and gently curved distal autozooidal peristomial component, forming a sharp angle with the frontal wall of the next zooid; the pattern of zooidal budding, achieved via development of a partition from the floor of the parent zooid in its distal quarter to third, leaving the proximal portion of daughter zooids not overlapping, so that preceding and subsequent zooids are not appressed along their proximal segments; props are uniformly straight and filiform, with their diameter much smaller than in P. helix; the exceptionally rare presence of slit-like pseudopores, restricted to props; and wedge-shaped crystallites on the internal surface of developing zooids, with irregular, ragged edges. The discovery of P. fragilis suggests that Pandanipora is most likely a relict element of a more-widespread ancient distribution that existed in tropical and boreal zones of both the Atlantic and Pacific Oceans prior to formation of the Isthmus of Panama in the Pliocene.

Computer-Aided System Application Value for Assessing Hip Development

PurposeA computer-aided system was used to semiautomatically measure Tönnis angle, Sharp angle, and center-edge (CE) angle using contours of the hip bones to establish an auxiliary measurement model for developmental screening or diagnosis of hip joint disorders.MethodsWe retrospectively analyzed bilateral hip x-rays for 124 patients (41 men and 83 women aged 20–70 years) who presented at the Affiliated Zhongshan Hospital of Dalian University in 2017 and 2018. All images were imported into a computer-aided detection system. After manually outlining hip bone contours, Tönnis angle, Sharp angle, and CE angle marker lines were automatically extracted, and the angles were measured and recorded. An imaging physician also manually measured all angles and recorded hip development, and Pearson correlation coefficients were used to compare computer-aided system measurements with imaging physician measurements. Accuracy for different angles was calculated, and the area under the receiver operating characteristic (AUROC) curve was used to represent the diagnostic efficiency of the computer-aided system.ResultsFor Tönnis angle, Sharp angle, and CE angle, correlation coefficients were 0.902, 0.887, and 0.902, respectively; the accuracies of the computer-aided detection system were 89.1, 93.1, and 82.3%; and the AUROC curve values were 0.940, 0.956, and 0.948.ConclusionThe measurements of Tönnis angle, Sharp angle, and CE angle using the semiautomatic system were highly correlated with the measurements of the imaging physician and can be used to assess hip joint development with high accuracy and diagnostic efficiency.

On the application of the theory of dissociation of electrolyte solutions of Arrenius to electrophysiology

It is known that if we make a transverse cut of the muscle at a right angle to its axis, then the points located at an equal distance and symmetrical with respect to the center of the cut surface will have the same potentials, and therefore, when we move away from these places, we will not receive any current; if the cut is made with a greater or lesser sharp angle, then when two symmetrical points of such a transverse cut are retracted, one of which is closer to the obtuse one and the other to the acute angle, the current is obtained, and it turns out that the place lying at the obtuse angle is always positively in relation to lying in acute. These currents are called tilt currents.