Magnetic Plate Research Articles

Effective periodate activation by the ball-milled bimetallic zero-valent iron/manganese oxides catalyst for sulfamethoxazole degradation

Developing a green and efficient catalyst for oxidant activation to tackle refractory organics pollution is challenging for water purification. In this study, we prepared a zero-valent iron-based bimetallic catalyst (ZVI/Mn3O4) for periodate (PI) activation using a simple and convenient ball-milling method. Electrochemical characterization and theoretical calculations confirm that the synergy between Fe and Mn enables the ZVI/Mn3O4 system to exhibit higher electron transfer efficiency compared to its individual components. Consequently, the ZVI/Mn3O4/PI system demonstrated enhanced PI activation and significantly improved removal of sulfamethoxazole (SMX), with reaction rates being 18.61 to 57.01 times higher than the comparison systems. The influence of various physicochemical parameters on SMX removal was investigated, confirming the wide tolerance ZVI/Mn3O4/PI system towards multiple aqueous matrices. Furthermore, the scalability of this system for industrial applications was validated through the preparation of larger batches of catalysts (4.21 g per batch) and testing in a custom-designed magnetic plate continuous-flow reactor. Quenching experiments and electron spin resonance tests confirmed that •O2– and 1O2 were the primary reactive species responsible for SMX degradation, with no toxic iodine byproducts detected, attributed to the carefully designed catalyst, which optimized the interaction between PI and the catalyst. Based on these findings, a potential catalytic mechanism and degradation pathway were proposed, highlighting ZVI's role as an electron pump to enhance Mn3O4's activation of PI. Additionally, toxicity assessments via prediction, zebrafish cultivation, wheat germination, and E. coli culture confirmed the excellent detoxification capability of ZVI/Mn3O4/PI system for SMX degradation. Overall, this work provides a new research paradigm for the convenient manufacture of ZVI-based catalysts and the development of advanced techniques for PI activation in water purification.

Piezoelectric Shunt Damping for a Planar Motor Application under Cryogenic Conditions

For several decades, Moore’s law has driven the semiconductor industry, with computational power and production costs as the main drivers. Such drivers have enabled several technological innovations in the mechatronics and dynamics architecture of photolithography machines, used for semiconductor circuits manufacturing. Among current investigations, the use of superconductive magnets would enable higher accelerating stages and, thus, higher throughput and lower manufacturing costs. However, this involves a complex magnet structure that needs to operate at cryogenic temperatures and mechanical resonances at relatively low frequencies as a result of the thermal architecture of the system. The damping options are also limited due to the very low temperature. This paper explores the use of shunted piezoelectric transducers for damping the internal modes of the magnet mass. A classical resistive and inductive RL shunt is considered. The study was conducted both numerically and experimentally on a demonstrator of a superconductive magnet plate concept, where piezoelectric transducers are incorporated to support the superconducting coils. The study demonstrates the effectiveness of piezoelectric shunts as a damping solution at very low temperatures, with limited impact of the temperature variation on the performance.

B-167 Quantification of Thyroglobulin in Serum for Clinical Research using SISCAPA Workflow Combined with LC-MS/MS

Abstract Background Accurate measurement of Thyroglobulin (Tg) using existing immunoassay-based techniques can be challenging in the presence of anti-Tg antibodies (TgAb), which can prevent the binding of Tg to assay antibodies thus leading to non-quantifiable Tg concentrations. The Stable Isotope Standards and Capture with Anti-Peptide Antibodies (SISCAPA™) Workflow combined with LC-MS/MS has been successfully employed to circumvent this problem by digesting the serum sample thus eliminating interfering TgAb and measuring a Tg-specific surrogate peptide instead. Methods Using a Andrew+™ Pipetting Robot, denaturation and reduction buffer was added to 250µL serum samples and incubated at 37°C. Internal standard and trypsin were added and samples incubated at 37°C. The samples were quenched with protease inhibitor and Anti-Tg FSP mAb SISCAPA was added to the serum samples and mixed for 60 minutes. Using a magnetic array plate, the beads were left to pull down, samples were discarded, and the beads were twice washed with PBS/CHAPS prior to elution with acetonitrile with formic acid. Using an ACQUITY™ UPLC™ I-Class PLUS FL System, samples were injected onto a Waters™ XSelect™ HSS T3 Column using a water/acetonitrile/formic acid gradient elution profile and the Tg FSP peptide was quantified using a Waters Xevo™ TQ Absolute Mass Spectrometer. Results The method demonstrated no significant carryover or matrix effects and was shown to be linear from 0.1 - 50 ng/mL. Analytical sensitivity investigations indicate the analytical sensitivity of this method would allow precise quantification (<20%) at 0.1 ng/mL with S/N (PtP) >10:1. Coefficients of variation (CV) for total precision and repeatability on 5 analytical runs for low, mid and high QCs were all < 9.5% (n = 25) for both automated and manual precision assessments. Comparison with samples from the UK NEQAS scheme demonstrated significant method bias of -40% for the developed LC-MS/MS method. Re-assignment of the calibrator concentrations using the EQA samples reduced the bias to -5.5%, indicating differences in the calibration materials used for these measurements. Conclusions A LC-MS/MS clinical research method for serum thyroglobulin was developed using SISCAPA, followed by analysis using ACQUITY UPLC I-Class PLUS FL System and the Xevo TQ Absolute Mass Spectrometer. The method provides analytical sensitivity down to 0.1 ng/mL from 250 µL serum, while providing sufficient sample for re-analysis. The method demonstrates excellent linearity across the calibration range, with no significant carryover, interferences, and matrix effects. Total reproducibility and repeatability of the method was ≤9.5% RSD for manual and automated sample preparation, using the Andrew+ Pipetting Robot. In addition, the Andrew+ Pipetting Robot can minimize user touch-time, allowing a full plate to be prepared within four hours without user intervention.

Reconstruction of the shape of a flaw in ferromagnetic plate by solving inverse problem of magnetostatics and series of direct problems

The article presents a verification technique for solving the inverse geometric problem of magnetostatics in a soft magnetic ferromagnet plate. The technique involves solving a number of direct problems, in which the shape of the defect obtained by solving the inverse geometric problem of magnetostatics is used as a first approximation, and then increasing or decreasing the depth of the defect without changing the shape of the boundary surface — comparing the topographies of the magnetic field components obtained during measurements above the plate surface and calculated (as a result of solving the direct problem) at the same points of the components of the magnetic stray field from the reconstructed three-dimensional defect. As a result of applying the technique, the geometric parameters of the defect under study can also be refined. Obtaining the initial conditions for solving the inverse problem and solving direct problems of magnetostatics is carried out using the finite element method in the ELMER program. The technique works with one-sided access to any surface of the plate (a defect-free surface or a surface with a defect).

Machine learning enabled classification of lung cancer cell lines co-cultured with fibroblasts with lightweight convolutional neural network for initial diagnosis

BackgroundIdentification of lung cancer subtypes is critical for successful treatment in patients, especially those in advanced stages. Many advanced and personal treatments require knowledge of specific mutations, as well as up- and down-regulations of genes, for effective targeting of the cancer cells. While many studies focus on individual cell structures and delve deeper into gene sequencing, the present study proposes a machine learning method for lung cancer classification based on low-magnification cancer outgrowth patterns in a 2D co-culture environment.MethodsUsing a magnetic well plate holder, circular pattern lung cancer cell clusters were generated among fibroblasts, and daily images were captured to monitor cancer outgrowth over a 9-day period. These outgrowth images were then augmented and used to train a convolutional neural network (CNN) model based on the lightweight TinyVGG architecture. The model was trained with pairs of classes representing three subtypes of NSCLC: A549 (adenocarcinoma), H520 (squamous cell carcinoma), and H460 (large cell carcinoma). The objective was to assess whether this lightweight machine learning model could accurately classify the three lung cancer cell lines at different stages of cancer outgrowth. Additionally, cancer outgrowth images of two patient-derived lung cancer cells, one with the KRAS oncogene and the other with the EGFR oncogene, were captured and classified using the CNN model. This demonstration aimed to investigate the translational potential of machine learning-enabled lung cancer classification.ResultsThe lightweight CNN model achieved over 93% classification accuracy at 1 day of outgrowth among A549, H460, and H520, and reached 100% classification accuracy at 7 days of outgrowth. Additionally, the model achieved 100% classification accuracy at 4 days for patient-derived lung cancer cells. Although these cells are classified as Adenocarcinoma, their outgrowth patterns vary depending on their oncogene expressions (KRAS or EGFR).ConclusionsThese results demonstrate that the lightweight CNN architecture, operating locally on a laptop without network or cloud connectivity, can effectively create a machine learning-enabled model capable of accurately classifying lung cancer cell subtypes, including those derived from patients, based upon their outgrowth patterns in the presence of surrounding fibroblasts. This advancement underscores the potential of machine learning to enhance early lung cancer subtyping, offering promising avenues for improving treatment outcomes in advanced stage-patients.

Construction of an S-scheme electron transfer channel in Cu0/CuFe2O4 magnetic plate column reactor for the LEV degradation: New strategy of visible Photo-Fenton system application

The complicated loading process and easy falling off of powder catalysts still restrict the wide application of Photo-Fenton technology in practical water treatment. In this study, a magnetic fixed film plate column water treatment equipment is designed as a visible Photo-Fenton reactor to remove levofloxacin (LEV). The effect of magnetic force can ensure that the catalyst is firmly fixed, and the multi-level shallow column plate structure achieves full contact and efficient reaction between the catalyst and wastewater. Simultaneously, the Cu0/CuFe2O4 (STCCF) utilizes Cu0 to construct an S-scheme electron transfer channel, which improves the separation efficiency of photo-generated carriers and provides sufficient photo-generated electrons for the reduction of Fe (Ⅲ) and Cu (Ⅱ). The pseudo-first-order reaction kinetic constant k for the degradation of LEV in the visible Photo-Fenton system is 0.0349 min−1, which is 15.9 times that of the photocatalytic system and 4.8 times that of the Fenton system. After continuous operation for 72 h, the magnetic fixed film plate column reactor can still remove more than 90 % of LEV and 82 % of COD in the secondary effluent of simulated antibiotic pharmaceutical wastewater treatment process, and the effluent is stable and meets the standard. The magnetic fixed film plate column reactor can be used for advanced treatment of antibiotic pharmaceutical wastewater. This study provides a new insight into the application of the Photo-Fenton process.

The Effect of Magnetic Therapy on Postoperative Urinary Retention in Patients Undergoing Surgery: A Randomized Clinical Trial.

Urinary retention is a postoperative problem that causes pain and discomfort for patients, even when catheters are used. The potential role of magnetic therapy in treating postoperative urinary retention through acupuncture points remains uncertain. This research aims to assess the impact of magnetic therapy on urinary retention in patients undergoing surgery. This single-blind clinical trial study was conducted in a recovery department within an operating room and subsequently in the Surgery Department of Amin Hospital. The study took place in Isfahan in 2022, with a sample of 64 patients selected using a simple random sampling method and divided equally into two groups. In the intervention group, magnet plates were applied, while the control group received iron plates at seven specific points for duration of 35 ± 5 minutes. Demographic information, the type of urinary excretion, the duration of urinary retention, and the volume of excreted urine were recorded using a researcher-made checklist for both intervention and control groups. These data were compared and subjected to descriptive and analytical statistical analysis. Among the participants (N = 64), the majority were male (N = 37, 57.80%), and the mean age was 40.17 years. The Chi-square analysis revealed no significant difference between the intervention and control groups in terms of the type of urinary excretion (p = 0.106). However, the Mann-Whitney U-test demonstrated significant difference between the two groups regarding the duration required to eliminate urinary retention and the volume of excreted urine (F2,41 = 62 and F1,76 = 62; p < 0.001). The use of a novel approach involving magnetic therapy applied to acupuncture and reflexology points has been shown to reduce the time required for the first urination and increase the volume of urine in post-surgery patients.

Dual-recognition colorimetric platform based on porous Au@Pt nanozymes for highly sensitive washing-free detection of Staphylococcus aureus.

Adual-recognition strategy is reportedto construct a one-step washing and highly efficient signal-transduction tag system for high-sensitivity colorimetric detection of Staphylococcus aureus (S. aureus). The porous (gold core)@(platinum shell) nanozymes (Au@PtNEs) as the signal labels show highly efficient peroxidase mimetic activity and arerobust. For the sake of simplicity the detection involved the use of a vancomycin-immobilized magnetic bead (MB) and aptamer-functionalized Au@PtNEs for dual-recognition detection in the presence of S. aureus.In addition, we designed a magnetic plate to fit the 96-well microplate to ensure consistent magnetic properties of each well, which can quickly remove unreacted Au@PtNEs and sample matrix while avoiding tedious washing steps. Subsequently, Au@PtNEs catalyze hydrogen peroxide (H2O2) to oxidize 3,3',5,5'-tetramethylbenzidine (TMB) generating a color signal. Finally, the developed Au@PtNEs-based dual-recognition washing-free colorimetric assay displayed a response in the range of S. aureus of 5 × 101-5 × 105 CFU/mL, and the detection limit was 40 CFU/mL within 1.5 h. In addition, S. aureus-fortified samples were analyzed to further evaluate the performance of the proposed method, which yielded average recoveries ranging from 93.66 to 112.44% and coefficients of variation (CVs) within the range 2.72-9.01%. These results furnish a novel horizon for the exploitation of a different mode of recognition and inexpensive enzyme-free assay platforms as an alternative to traditional enzyme-based immunoassays for the detection of other Gram-positive pathogenic bacteria.

SYNTHESIS AND CHARACTERIZATION OF PURE AMORPHOUS SILICON OXIDE FROM TREATED KAOLINITIC CLAY USING CHEMICAL EXTRACTION

Pure silicon oxide was produced in this study utilizing a sodium silicate solution made from Kankara clay as a precursor. The Kankara clay that was obtained from Nigeria was first beneficiated to produce pure dried powder clay. After that, the dried powdered clay was treated with heat activation and acid leaching, respectively. In a 500 mL Erlenmeyer flask, appropriate amounts of each clay (raw, thermally treated clay, and leached clay) were reacted with 3M NaOH solution. The flask was heated to 200°C and stirred continuously for 3 hours on a magnetic stirring hot plate connected to a reflux condenser. The solution was filtered to yield sodium silicate solution, which was then precipitated with 3M HCl while constantly stirring to produce a gelly-like white substance. The gel was aged for 18 hours, then washed with de-ionized water several times before being dried at 80°C for 12 hours to get pure white silica particles, which were subsequently described. The XRD analysis revealed that the silicon oxide synthesized is amorphous, but the microstructure evaluation revealed particles aggregation, which is usual in sol-gel synthesized powder.

A novel industrial magnetically enhanced hydrogen production electrolyzer and effect of magnetic field configuration

Hydrogen energy is a clean, zero‑carbon, flexible and abundant secondary energy. The large-scale deployment of industrial hydrogen production equipment is an effective way to improve renewable energy consumption, the efficiency of hydrogen production from water electrolysis is crucial for equipment deployment. In this paper, a novel industrial magnetically enhanced AWE electrolyzer is designed to improve the efficiency of hydrogen production. The structure and assembly method of the magnetic bipolar plate are introduced, the BOP component is designed and an industrial system-level test platform is built. The results show that the magnetic enhanced electrolyzer can effectively improve the hydrogen production efficiency, however, the effects of different magnetic field configurations (Magnetic field horizontal configuration, MFHC; Magnetic field vertical configuration, MFVC; No magnetic field configuration, NMFC) are significantly different. The magnetic field of MFVC are concentrated inside the bipolar plate and perpendicular to the direction of the electric field, and there is almost no magnetic flux leakage inside the cathode and anode cells. The magnetic field and the electric field of the MFHC configuration are not completely perpendicular, the magnetic field distribution is irregular, there are more magnetic flux leakage in the cells, and the magnetic field intensity is obviously greater than that of the MFVC configuration. Compared with NMFC, MFHC and MFVC significantly improved the hydrogen production efficiency, MFHC performance is better, the current density increased by 28.48% (@50 °C-100 L/h-2 V cell voltage-30%wt KOH), DC power consumption was reduced by 6.2% (CC100A-100 L/h-30%wt KOH). The design method and configuration scheme of magnetically enhanced electrolyzer provide a new idea for the industrial application of magnetic fields in AWE hydrogen production equipment.

Enhancing the mechanical and magnetic properties for low magnetic stainless-steel plates by non-recrystallization hot rolling and solution treatment

Enhancing the mechanical and magnetic properties for low magnetic stainless-steel plates by non-recrystallization hot rolling and solution treatment

Field stiffening: A way to break the bounds on the properties of composites

It is common practice for humans to enhance the stiffness of a material by adding stiffer ingredients into it, which leads to the development of various composites of wide applications. However, irrespective of the configuration of the constituents of a multiphase composite, its compression elastic moduli are always between some bounds which are determined by the volume fractions and elastic moduli of the constituents inherently. Here, we report a magnetic composite material that is composed of a soft matrix material and two magnetic thin plates with small volume fraction. The compressive elastic modulus of the composite material is 25 times higher than the Halpin-Tsai upper bound due to the effect of the internal magnetic field. The measured maximum initial tangent modulus of the magnetic composite is ca. 40 times and 54 times higher than that of the nonmagnetic composite and PDMS matrix, respectively. This work provides a new direction for improving the performance of materials by fields.

Studying the electrode distribution in a rotary triboelectric nanogenerator using a magnetic stir plate

Triboelectric nanogenerators (TENGs) were invented to harvest energy from the contact electrification between two materials by electrostatic induction. TENGs have attracted much attention over the last few decades because of the large variability of low-cost materials, their high voltage output, and low current range. The rotatory TENG (R-TENG) is one of the most common operational mode with demonstrated high performance according to their design and working parameters. Designing and understanding TENGs is an ongoing research challenge for those who are new to this field. Herein, we provide a simple reproducible design of R-TENGs using a Teflon™ stir bar in a polystyrene Petri dish to study the effect of electrode distribution and the influence of the triboelectric pair on the electrical output.

Indium Recovery from End-of-Life E-Waste: Important Details Related to Spectroanalytical Determination and Recycling Viability

Recycling has experienced great interest over the past five years, primarily driven by its strategic economic significance and the growing scarcity of natural resources. One element that has garnered attention is indium (In), especially due to its presence in flat panel displays (FPDs), particularly in devices utilizing liquid crystal display (LCD). The goal of this research was to establish a method for extracting In from LCD. The study faced challenges related to In determination using inductively coupled plasma optical emission spectroscopy (ICP OES), and furthermore, it proposed an optimized extraction method through design of experiments (DoE), focusing on extraction time and percentage of solid variables. Diverse sample types encompassing smartphones, monitors, and television screens were processed. Leaching was conducted utilizing a magnetic plate at 80 °C, employing a 1 mol L-1 H2SO4 solution along with 25% m v-1 of the sample. This proposed method achieved a near-complete extraction rate (100%) for In. Moreover, in-depth interviews were conducted with several stakeholders in urban mining and various sectors within Brazil. The insights gleaned from these interviews showed the absence of a consolidated market for recycling LCDs with a specific emphasis on In recovery.

Analysis of the absorbing boundary condition for the Maxwell fluid flow over a semi-infinite plate with considering the magnetic field

In this paper, we analyze the flow mechanism of the Maxwell fluid over a semi-infinite plate. To handle the semi-infinite boundary, the artificial boundary method is employed and the absorbing boundary condition in the form of convolution is derived. Besides, the stability of the absorbing boundary condition is analyzed. Solutions are obtained numerically using the finite difference method and the accuracy is verified by introducing a source term to construct the exact solution. To demonstrate the validity and reasonableness of the absorbing boundary condition, a comparison with the direct truncation boundary is discussed. Our study examines the effects of the magnetic field, relaxation parameter, oscillation frequency and plate amplitude on the velocity distribution and flow mechanism of the Maxwell fluid.

Efficacy of Auricular Point Acupressure with Magnetic Plates on Postpartum Anxiety and Depression in Low Risk Parturient at Thammasat University Hospital: A Randomized Clinical Controlled Trial

Objective: To study the effectiveness of auricular acupressure (AC) with and without magnetic plates in reducing anxiety and depression levels among parturients. Materials and Methods: The present study was a randomized controlled trial conducted at the department of Obstetrics and Gynecology, Thammasat University Hospital, Pathum Thani, Thailand, between March 2022 and February 2023. All participants were term nulliparous pregnant women delivered who during the study period. Participants were randomly allocated into three groups with control for non-AC, study for AC with magnetic plates, and placebo for AC with non-magnetic plates. Three specific auricular points, namely Shenmen (HT7), Heart (CO15), and Subcortex (AT4) were selected. Thai Hospital Anxiety and Depression Scale (Thai HADS) was evaluated at 2, 14, 28, and 42 days postpartum. Results: Two hundred twenty-five cases were recruited and divided evenly into control, study, and placebo groups. The mean age of participants was 28.5 years old. Body mass index (BMI), education level, and demographic characteristics among the three groups were comparable. Prevalence of anxiety and depression was 4.4% (10/225) and 7.5% (17/225). Participants in placebo and study groups had statistically significant relief of anxiety levels within six weeks when compared to the control group. All subjects had lower depression scores within four weeks of delivery. AC with and without magnetic plates reduced postpartum depression compared to the control group. Satisfaction of AC was reported at 84% (126/150). Conclusion: AC with or without magnetic plates at HT7, CO15, and AT4 significantly reduced anxiety and decreased depression with less confidence in postpartum subjects. Keywords: Auricular acupressure; Anxiety; Depression; Postpartum; Magnetic plates

A Mini Review: Preliminary Study of Bio-Medical Physics on Development of FRRS to Reduce Pain After Heavy Activities

Reflexology on the feet is a traditional Chinese medicine (TCM) therapy method. Specifications that must be considered in the manufacture of electrostimulators for acupuncture therapy are waveform, intensity, frequency, and duration of therapy. Scientific studies have confirmed that TCM FB can promote microcirculation, improve skin permeability, and boost drug absorption. Based on data from research collected in the last five years, the method used for foot reflexology is TENS, FES, FNS, and the manufacture of reflexology cotton sandals. By looking at these significant results of the usage of foot stimulator, but it has not been supported by the development of a comprehensive foot reflexology device. Thus, the development of the FRRS device has the potential to become a non-invasive and non- pharmacological therapy device with several advantages in its usage using magnetic electrodes (magnetic plate electrodes), which are very effective at directing the flow of electrical energy to the body through the soles of the feet.

Comparison and Efficacy of Auricular Point Acupressure with Auricular Patches on Lactation in Nulliparous Postpartum Cesarean Delivery Parturients at Thammasat University Hospital: A Randomized Controlled Trial

Objective: To compare the lactation enhancing effect of auricular acupressure with or without a magnetic plate on post-cesarean nulliparous parturients. Materials and Methods: The present study was a randomized controlled trial conducted in the obstetrics ward of Thammasat University Hospital, Pathum Thani, Thailand between February and July 2022. Participants were term nulliparous pregnant women aged between 20 and 40 years old who underwent cesarean delivery. They were allocated into three groups, namely magnetic (M), non-magnetic (NM), and control groups. The standard care plan for post-cesarean cases was applied to all patients. Participants in both M and NM groups were assigned to receive auricular acupressure using auricular patches with and without magnetic plates, respectively. The ear pinna has five specific auricular points, namely chest (AH10), endocrine (CO18), stomach or Wei (CO4), spleen or Pi (CO13), and sympathetic points (AH6a). The treatment began immediately after counseling and continued for seven days. The onset of the first lactation, lactation visual assessment (LVA) level was collected using the survey form. Exclusive breastfeeding was encouraged at a rate of every three hours to meet newborn demands. The onset of lactation was assessed within three hours after auricular acupressure and every time before breastfeeding. Results: Seventy-five pregnant women were recruited and allocated with 25 cases per group. Mean maternal age was 30 years. The demographic characteristics of the three groups were comparable. There were more participants in the M group had onset of lactation within 24 hours, than in the control group significantly, at 20 versus 13, respectively (p=0.039). Onset of LVA level 1, 2, and 4 in the three groups were comparable. The onset of LVA level 3 in the M group was significantly faster than the control group (p=0.023). Satisfactory lactation and auricular acupressure among M and NM groups were comparable. Conclusion: Auricular acupressure with magnetic plates significantly enhanced lactation onset and lactation visual volume (level 3) in postcesarean nulliparous parturients. It merits consideration to be included in routine practice. Keywords: Cesarean delivery; Postpartum lactation; Auricular acupressure

Numerical Simulation of the Spatial Distribution of the Magnetic Field in Devices for the Magnetic Sedimentation of Nanoparticles from Aqueous Media

Abstract—A method of magnetic sedimentation using a permanent magnets is a promising “green” technology to separate nanoparticles from water. In this work, numerical simulation of the magnetic field distribution in the devices based on combination of alternating flat permanent magnets (NdFeB) and soft magnetic steel inserts is carried out. Two types of devices with different magnetization directions of permanent magnets are considered: vertical (V) and horizontal (G). A criterion for evaluating the performance of the magnetic device R is proposed, depending on the effective volume of the water area, where the value of the product \({\text{|}}{{B}_{z}}d{{B}_{z}}{\text{/}}dz{\text{|}}\) 4 T2/m is realized, where Bz is the vertical component of magnetic induction. The dimensions of the permanent magnets and soft magnetic inserts along the horizontal x axis, the ratio of the thicknesses of magnetic and steel plates, and the number of plates are varied. It is shown that the maximum value R = 31% is performed using the V-type magnetic device with the thickness of the magnetic (Lx) and the steel (Ls) elements 30 mm and 2.5 mm, respectively. For G-type magnetic device maximum value R = 19% is realized at Lx = 12.5 mm and Ls = 10 mm. Magnetic devices are effective for the height of a water layer 20 mm at the given dimensions of the magnetic system.

Dual catheter and double-lumen cerebrospinal fluid shunt systems with backflow mechanisms.

We previously developed a novel functional benchtop apparatus to simulate catheter occlusion in vitro utilizing avian vitelline membrane and chalaza to test catheter designs and de-obstruction techniques. Here, we study the integration of double-lumen catheter-mediated backflow in the shunt system assembly and its potential for an in-line de-obstruction of an obstructed ventricular catheter. A double-lumen catheter was connected to a standard proximal shunt catheter for all trials. One limb of the double-lumen catheter was connected to the backflow mechanisms and allowed to loop back for fluid access. A micropump and a bi-corporal electromagnetic pump were utilized to provide various degrees of backflow at predetermined intervals. Flow rates were measured after initial occlusion and after implementation of the backflow mechanisms, and degrees of catheter blockage was calculated as a percentage of the unoccluded flow rate. Flow visualization was also used. In baseline blockage of less than 50%, the average occluding agent weighed 0.3-0.6 g with baseline flow rates of 8.5-11.9 mL/min. After 5 min of backflow using a micropump, the degree of blockage was reduced in 50% of trials. Additional backflow for 5 min did not provide further improvements in flow rate. In baseline blockage of greater than 50%, the average occluding agent weighed 0.8-1.3 g with baseline flow rates of 1.1-4.2 mL/min. After 5 min of backflow, the system demonstrated a decreased blockage in 20% of trials; additional backflow for 5 min further improved the flow rate in 40% of the total trials. Only magnetic plates provided enough force to provide pulsatile backflow in the bi-corporal electromagnetic system. The preliminary results of connecting a standard proximal catheter in series with a double-lumen catheter show a slight change in the percent occlusion from the baseline status several times when the retrograde flow occurred via one limb of the catheter. Additionally, the de-obstruction seems related to the length of the interval of the backflow and the initial percentage occlusion of the proximal catheter. The statistical analysis does not reveal a statistically significant reduction in occlusion in the proximal catheter with either backflow interval.