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A boom in exploration for marine geology and ocean resources has resulted in a huge demand for radio navigation or special environment communications, in turn spurring the rapid development of portable underwater wireless communication technology. State of the art acoustic communication methods used today are plagued by substantial transmission delays, multipath effects, and doppler frequency shifts, among other challenges, thus impeding the advancement of underwater wireless communication technology. Low-frequency electromagnetic transmission has proven to be a prospective solution for underwater communication, but the conventional electrical antennas is too large for portable underwater wireless communication. Emergent magnetoelectric (ME) antennas driven by piezoelectric materials have become a promising solution for miniaturizing very low frequency (VLF) communication systems. Here, a theoretical model between the radiation performance and piezoelectric material properties of the ME antenna was conducted. Guide by the theory analysis, Pb(In1/2Nb1/2)O3Pb(Mn1/3Sb2/3)O3Pb(Zr0.49Ti0.51)O3 (PIN-PMS-PZT) piezoelectric ceramic simultaneous with high d33 and Qm (d33 ∼ 401, Qm ∼ 1510) has been designed to enhance the magnetoelectric radiation of the VLF ME antenna. The PIN-PMS-PZT based ME antenna achieves a large converse magnetoelectric response 1.78 Gs⋅cm/V in EMR, which is almost doubled to commercial PZT based ME antenna. More importantly, a VLF communication system was built based on the VLF antenna, which successfully transmitted digital signals using Amplitude-Shift-Keying (ASK) modulation. It is believed that the presented work could provide a theoretical basis and feasible technical path for the employment of ME antennas in the future.

Abstract Wireless communication has always been an indispensable element in the modern information‐based society. Beyond the commercial electrical antenna, very low frequency (VLF) mechanical antennas have recently become research hotspot since their combination of miniaturization and favorable radiation efficiency in lossy electrically conductive environments. However, their usage is challenged due to the relatively limited radiation capability and modulation bandwidth. This study demonstrates an improved high‐efficiency magnetoelectric (ME) mechanical antenna based on the magneto‐mechano‐electric (MME) effect, realized via the synergistic effect of piezo‐driven magnets motion and converse magnetoelectricity (ME). Converse ME coefficient and radiation measurement show that the MME antenna demonstrates superior performance over a normal ME antenna. The oscillation magnet serves as an extra vibrating magnetic dipole besides the ME composite and thus brings radiation enhancement to the mechanical antenna. Furthermore, digital signal modulations are conducted with a VLF carrier signal to enable anti‐interference and anti‐attenuation communication. In view of the exemplary demonstration, the MME effect‐based antenna is expected to provide a new strategy for mechanical antenna improvement and shows tremendous potential for conductive environments communication applications.

This article is devoted to the theory of the converse magnetoelectric (CME) effect for the longitudinal, bending, longitudinal-shear, and torsional resonance modes and its quasi-static regime. In contrast to the direct ME effect (DME), these issues have not been studied in sufficient detail in the literature. However, in a number of cases, in particular in the study of low-frequency ME antennas, the results obtained are of interest. Detailed calculations with examples were carried out for the longitudinal mode on the symmetric and asymmetric structures based on Metglas/PZT (LN); the bending mode was considered for the asymmetric free structure and structure with rigidly fixed left-end Metglas/PZT (LN); the longitudinal-shear and torsional modes were investigated for the symmetric and asymmetric free structures based on Metglas/GaAs. For the identification of the torsion mode, it was suggested to perform an experiment on the ME structure based on Metglas/bimorphic LN. All calculation results are presented in the form of graphs for the CME coefficients.

This article presents a general theory of the ME effect in composites in the low- and high-frequency ranges. Besides the quasi-static region, the area of electromechanical resonance, including longitudinal, bending, longitudinal shear, and torsional modes, is considered in more detail. To demonstrate the theory, expressions of ME voltage coefficients are obtained for symmetric and asymmetric layered structures. A comparison is made with the experimental results for the GaAs/Metglas and LiNbO3/Metglas structures. The main microwave ME effect, consisting of the FMR line shift in an electric field, for the ferromagnetic metals, their alloys, and YIG ferrite using various piezoelectrics is discussed. In addition to analytical calculations, in the article, finite element modeling is considered. The calculation methods and experimental results are compared for some composites.

Aim To measure a calibre of radial and ulnar septocutaneous perforators at the anterior forearm, and to count its number in proximal, middle and distal thirds. Methods The study was conducted on 50 fresh amputated forearms (trauma, tumours) in the period between January 2012 and December 2021. Forearms were collected from several hospitals in Belgrade, and analysed at the Institute of Anatomy, Medical School, University of Belgrade, Serbia. Injection of ink-gelatin and fine dissection of autopsy material was performed on 30 forearms, and corrosion method with injecting methyl methacrylate for 3D analysis on the other 20 forearms. Results A mean calibre of septocutaneous perforators on the radial artery was 0.53±0.46 mm (0.2-0.85). Averagely, there were 8.1 radial artery septocutaneous perforators - two perforators on the proximal third, 3.7 on the middle third, and 2.7 on the distal third. The mean calibre of ulnar artery perforators was 0.65±0.35 mm (0.18-1.8). The average number of septocutaneous perforators of the ulnar artery was 5.6; 1.2 on the proximal third, two on the middle third, and 2.2 on distal third. Conclusion Determination of the origin, calibre and spreading directions of the arterial septocutaneous perforators on the anterior forearm provide quantification of data about arborisation of radial and ulnar septocutaneous perforators at the anterior forearm. Clinical relevance of those anatomical data is in defining of safe locations and dimensions of forearm fasciocutaneous flaps in plastic surgery.

Many studies of the ME effect have been carried out in the microwave range in connection with the possibility of creating new electronic devices. One of the main microwave ME effects is the FMR line shift in an electric field, and the purpose of this article is to compare the FMR line shift in the ME structure in an electric field for a number of ferromagnetic metals, their alloys, and YIG ferrite using various piezoelectrics. This article discusses the regimes when the bias field is directed along the main axes of the magnetic component, while, as is known, the observed effect is due only to deformation. As a result of the study, ME structures with maximum and minimum microwave ME effects were found. In addition, the “substrate effect” in the piezoelectric YIG-GGG structure is considered.

Aim To explore the experiences of anaesthesia nurses in assessing postoperative pain in patients undergoing total hip and/or knee arthroplasty. Methods Data were collected through four focus group interviews (FGI) using the critical incident technique (CIT). The participants were six men and 12 women, all registered nurses with further education in anaesthesia with at least five-year experience of caring for patients on a postoperative ward. Results Maintaining communication with orthopaedic patients, different ways to assess pain, the assessment of unresponsive patients, using pain assessment scales and different work circumstances influencing their use, were stated as the main problems the nurses emphasize while assessing the pain of patients. Conclusion Skills related to observing the behaviour and experience of pain in different individuals are needed to ensure an understanding of patients’ pain, as well as the patients’ ability to estimate their pain, where the intensity of the pain varies in different patients. Further studies are needed to examine the way health professionals assess pain, depending on the patients’ ability to transform their pain from a subjective feeling into an objective numeric grade. The way individuals assess their pain differently and the way the resulting knowledge and experience of postoperative care may help nurses and other health-care professionals.

Objective: The aim of this study was to evaluate the differences in transcranial electric motor-evoked potentials – TceMEP on upper limbs and the incidences of postoperative brachial plexopathy between patients with kyphotic and scoliotic trunk shapes. Methods: In the period of January 2011–January 2017, 61 consecutive patients (mean age: 18.4 years ± 4.4 years (range: 10–32)) with pediatric spinal deformity underwent surgery in our Department. Eight of them had a kyphotic trunk deformity (Scheuermann kyphosis, neurofibromatosis, posterior thoracic hemivertebra), and the rest of the 53 patients had a scoliotic trunk deformity (mostly adolescent idiopathic scoliosis – AIS, lateral hemivertebra). The TceMEP recordings in all four limbs were analyzed every 30 min, or upon the surgeon's command. Upper limb TceMEP recordings were used as a control of systemic and anesthetic related changes, and as the indicator of positioning brachial plexopathy. Results: Four out of 8 patients (50.0%) from the kyphotic group experienced noteworthy decreases in TceMEP amplitude (≥65%) in one or both arms, and only 2 out of 53 patients (3.8%) from the scoliotic group, confirming significant statistical difference (Chi-square 16.75, p

The article discusses the physical foundations of the application of the linear magnetoelectric (ME) effect in composites for devices in the low-frequency range, including the electromechanical resonance (EMR) region. The main theoretical expressions for the ME voltage coefficients in the case of a symmetric and asymmetric composite structure in the quasi-static and resonant modes are given. The area of EMR considered here includes longitudinal, bending, longitudinal shear, and torsional modes. Explanations are given for finding the main resonant frequencies of the modes under study. Comparison of theory and experimental results for some composites is given.

One of the new materials that have recently attracted wide attention of researchers are magnetoelectric (ME) composites. Great interest in these materials is due to their properties associated with the transformation of electric polarization/magnetization under the influence of external magnetic/electric fields and the possibility of their use to create new devices. In the proposed review, ME magnetic field sensors based on the widely used structures Terfenol—PZT/PMN-PT, Metglas—PZT/PMN-PT, and Metglas—Lithium niobate, among others, are considered as the first applications of the ME effect in technology. Estimates of the parameters of ME sensors are given, and comparative characteristics of magnetic field sensors are presented. Taking into account the high sensitivity of ME magnetic field sensors, comparable to superconducting quantum interference devices (SQUIDs), we discuss the areas of their application.

The paper is devoted to the possibility of using magnetoelectric materials for the production of a crankshaft position sensor for automobiles. The composite structure, consisting of a PZT or LiNbO3 piezoelectric with a size of 20 mm × 5 mm × 0.5 mm, and plates of the magnetostrictive material Metglas of the appropriate size were used as a sensitive element. The layered structure was made from a bidomain lithium niobate monocrystal with a Y + 128° cut and amorphous metal of Metglas. Various combinations of composite structures are also investigated; for example, asymmetric structures using a layer of copper and aluminum. The output characteristics of these structures are compared in the resonant and non-resonant modes. It is shown that the value of the magnetoelectric resonant voltage coefficient was 784 V/(cm·Oe), and the low-frequency non-resonant magnetoelectric coefficient for the magnetoelectric element was about 3 V/(cm·Oe). The principle of operation of the position sensor and the possibility of integration into automotive systems, using the CAN bus, are examined in detail. To obtain reliable experimental results, a special stand was assembled on the basis of the SKAD-1 installation. The studies showed good results and a high prospect for the use of magnetoelectric sensors as position sensors and, in particular, of a vehicle’s crankshaft position sensor.

The “ideal“ timing and modality of fracture fixation for unstable thoracolumbar spine fractures in multiply injured patients remains controversial. The concept of “damage control orthopedics” is expressed. We presented a case report of a 27 years' old male who sustained a multilevel spine fractures associated a floating knee (Fraser's Type A), ulna fracture and carpal scaphoid fracture in July 2014 after car accident (very high energy trauma). All these fractures were treated in early total care. We reported a case control to discuss about the early spinal total care associated at orthopedic total care in patients with multiple trauma.

Magnetoelectric (ME) composites that simultaneously exhibit ferroelectricity and ferromagnetism have recently gained significant attention as evident by the increasing number of publications. These research activities are direct results of the fact that multiferroic magnetoelectrics offer significant technological promise for multiple devices. Appropriate choice of phases with co-firing capability, magnetostriction and piezoelectric coefficient, such as Ni-PZT and NZFO-PZT, has resulted in fabrication of prototype components that promise transition. In this manuscript, we report the properties of Ni-PZT and NZFO-PZT composites in terms of ME voltage coefficients as a function of frequency and magnetic DC bias. In order to overcome the problem of toxicity of lead, we have conducted experiments with Pb-free piezoelectric compositions. Results are presented on the magnetoelectric performance of Ni-NKN, Ni-NBTBT and NZFO-NKN, NZFO-NBTBT systems illustrating their importance as an environmentally friendly alternative.

Cystic hygroma is the cystic variety of lymphangiomas. Its common site is cervico-facial region, followed by axilla, superior mediastinum, mesentery and retroperitoneal region. Its occurrence in upper extremity is rarely reported, whereas its location at sternum has not been reported before. We report two cases of cystic hygroma occurring at unusual sites.

Background: To study the aetiology, management and outcome of biliary perforations in paediatric age group. Patients and Methods: In a retrospective study, the records of patients presented with biliary peritonitis due to biliary perforations, managed from March 2006 to July 2009, are reviewed. Results: Eight male patients with biliary peritonitis due to biliary perforation were managed. These patients were divided in two groups, A and B. Group A, (n = 3) patients, had common bile duct (CBD) perforation, and Group B (n=5) patients had gallbladder perforation. The presenting features were abdominal pain, fever, abdominal distension, vomiting, constipation, jaundice and signs of peritonism. The management of CBD perforations in Group A was by draining the site of perforation and biliary diversion (tube cholecystostomy). In Group B, the gallbladder perforations were managed by tube cholecystostomy in four patients and cholecystectomy in one patient, however, one patient had to be re-explored and cholecystectomy performed due to complete necrosis of gall bladder. There was no mortality in our series. All patients were asymptomatic on regular follow-up. Conclusion: Early optimal management of biliary perforations remarkably improved the very high mortality and morbidity that characterised this condition in the past.

Magnetoelectric (ME) interaction in magnetostrictive-piezoelectric multiferroic structures consists in inducing the electric field across the structure in an applied magnetic field and is a product property of magnetostriction and piezoelectricity in components. ME voltage coefficient that is the ratio of induced electric field to applied magnetic field is the key parameter of ME coupling strength. It has been known that the ME coupling strength is dictated by the product of the piezoelectric and piezomagnetic coefficients of initial phases. As a result, using the laminates with graded piezoelectric and piezomagnetic parameters are a new pathway to the increase in the ME coupling strength. Recently developed models predict stronger ME interactions in composites based on graded components compared to homogeneous ones. We discuss predicting the ME coupling strength for layered structures of homogeneous and compositionally graded magnetostrictive and piezoelectric components based on the graphs of ME voltage coefficients against composite parameters. For obtaining the graphs, we developed equations for ME output in applied magnetic field for possible modes of operation and layered structure configurations. In particular, our studies have been performed on low-frequency ME coupling, enhanced ME effect in electromechanical resonance (EMR) region for longitudinal and bending modes. Additionally, ME coupling at magnetic resonance in magnetostrictive component and at overlapping the EMR and magnetic resonance is investigated. We considered symmetric trilayers and asymmetric bilayers of magnetostrictive and piezoelectric components and multilayered structures based on compositionally stepped initial components.

In this work a magnetoelectric (ME) current sensor design based on a magnetoelectric effect is presented and discussed. The resonant and non-resonant type of ME current sensors are considered. Theoretical calculations of the ME current sensors by the equivalent circuit method were conducted. The application of different sensors using the new effects, for example, the ME effect, is made possible with the development of new ME composites. A large number of studies conducted in the field of new composites, allowed us to obtain a high magnetostrictive-piezoelectric laminate sensitivity. An optimal ME structure composition was matched. The characterization of a non-resonant current sensor showed that in the operation range to 5 A, the sensor had a sensitivity of 0.34 V/A, non-linearity less than 1% and for a resonant current sensor in the same operation range, the sensitivity was of 0.53 V/A, non-linearity less than 0.5%.

We compared kinetic characteristic of unipolar, bipolar and total hip endoprostheses, implanted after dislocated femoral neck fracture. Ninety patients were divided into three groups (30 patients in each group); a group with unipolar partial hip endoprosthesis (UPEP), a group with bipolar partial hip endoprosthesis (BPEP) and a group with total hip endoprosthesis (TEP). The patients from different groups were paired by parameters which could influence the long term functional result: follow up period, comorbidities, functional capabilities before injury, etc. After the average follow up 3.8 +/- 1.9 years, a measuring of range of hip motions (ROM) was conducted. The largest mean amplitudes in flexion (104 degrees), extension (13 degrees), abduction (35 degrees) and external rotation (38 degrees) was achieved BPEP, the largest adduction (14 degrees) was achieved UPEP, and internal rotation (34 degrees) TEP. Differences in ROMs are partially related to the clinical parameters such as: level of the hip pain, gait pattern, age and rehabilitation period (P < 0.05). Measuring of ROMs is the most reliable part of the clinical exam and it does not depend on subjectivity of patient, as opposed to other clinical parameters (level of pain, walking distance, aids usage, etc). The results obtained are favorable for the bipolar hip endoprosthesis, and they can be related to the biomechanical differences between the three types of hip endoprostheses. Kinetic advantages of the BPEP as compared to the UPEP, can be explained by the BPEP's structure: two-level mobility and a thinner neck which delays impingement in the late motion phase. In comparison to the TEP, clinical advantages of the BPEP can be attributed to less extensive surgery and scarring.