Toward Digital Twin Development for Implant Placement Planning Using a Parametric Reduced-Order Model.

Real-time stress distribution data for implants and cortical bones can aid in determining appropriate implant placement plans and improving the post-placement success rate. This study aims to achieve these goals via a parametric reduced-order model (ROM) method based on stress distribution data obtained using finite element analysis. For the first time, the finite element analysis cases for six design variables related to implant placement were determined simultaneously via the design of experiments and a sensitivity analysis. The differences between the minimum and maximum stresses obtained for the six design variables confirm that the order of their influence is: Young's modulus of the cancellous bone > implant thickness > front-rear angle > left-right angle > implant length. Subsequently, a one-dimensional (1-D) CAE solver was created using the ROM with the highest coefficient of determination and prognosis accuracy. The proposed 1-D CAE solver was loaded into the Ondemand3D program and used to implement a digital twin that can aid with dentists' decision making by combining various tooth image data to evaluate and visualize the adequacy of the placement plan in real time. Because the proposed ROM method does not rely entirely on the doctor's judgment, it ensures objectivity.

Sustained activation of persulfate by slow release of Fe(II) from silica-coated nanosized zero-valent iron for in situ chemical oxidation.

Sustained activation of persulfate through the slow release of Fe(II) from silica-coated nanosized zero-valent iron (nZVI) particles (nZVI@SiO2) was investigated. Slow release of Fe(II) prevented radical scavenging by excess Fe(II) and increased the radical yield, which improved the stoichiometric efficiency of phenol degradation. Sulfate and hydroxyl radicals were found to be the main oxidative species produced during phenol degradation and were found to make comparable contributions to oxidation. The nZVI@SiO2 particle silica shell thickness controlled the release of Fe(II) and therefore the sustained activation of persulfate and was strongly affected by the synthesis conditions, including the [Si]/[Fe] ratio and silica supply rate. Optimal sustained phenol degradation was achieved when nZVI@SiO2 particles were synthesized using a [Si]/[Fe] ratio of 0.5 and a tetraethyl orthosilicate supply rate of 0.5 mL/min, and this was attributed to the nZVI@SiO2 particles giving an optimal Fe(II) release rate and therefore a high persulfate activation rate and a high phenol removal efficiency. Sustained persulfate activation induced by Fe(II) being slowly released was described well by single-stage first-order kinetics rather than two-stage first-order kinetics typical of unmodified nZVI/persulfate systems. Persulfate was found still to be activated by iron (oxyhydr)oxides minerals after the nZVI@SiO2 particles had been exhausted but the persulfate sustained activation induced by the slow release of Fe(II) played a crucial role in determining the overall degradation efficiency. The results highlight the importance of the slow release of Fe(II) from nZVI-based materials for in situ chemical oxidation through sustained persulfate activation.

Continuous Fe(II)-dosing scheme for persulfate activation: Performance enhancement mechanisms in a slurry phase reactor.

Mechanisms involved in the superior performance of the continuous Fe2+ dosing scheme over the single Fe2+ dosing scheme was thoroughly investigated. The kinetics and stoichiometry of the phenol removal/persulfate consumption strongly depended on the volumetric or molar Fe2+ feeding rate, Fe2+ concentration in the feed solution, and Fe2+ feeding mode (continuous or single dose). The process performance was determined by the molar Fe2+ feeding rate rather than the volumetric Fe2+ feeding rate or the Fe2+ concentration in the feed solution. The phenol degradation rate increased as the molar Fe2+ feeding rate increased to 2.77 mmol/min but decreased as the Fe2+ feeding rate increased further. The sulfate radical was predominant radical species formed in continuous Fe2+ dosing mode. The hydroxyl and sulfate radicals were both important in single Fe2+ dose mode. The presence of hydroxyl radicals in single Fe2+ dosing mode decreased the amount of phenol oxidation that occurred, probably because the hydroxyl radicals were readily scavenged by soil organic matter. Continuous Fe2+ dosing facilitated phenol mineralization, which was indicated by total organic carbon measurements and toxicity tests performed using Hyalella azteca.

Activation of persulfate by humic substances: Stoichiometry and changes in the optical properties of the humic substances.

Persulfate activation through electron transfer from humic substances (HS) was investigated. Persulfate consumption in the presence of standard HS and HS model compounds linearly correlated with the phenol contents of the HS. Redox-active carbonyl groups such as aromatic ketones and quinone also contributed to persulfate consumption by donating electrons while being reduced. Phenols activated persulfate through direct electron transfer from the phenolate forms but reduced ketones activated persulfate through reactions between their organic radicals and persulfate. Persulfate was activated more by terrestrially derived aquatic HS containing large numbers of phenol groups than by other species, and this caused more benzene oxidation to occur in the presence of terrestrially derived aquatic HS than in the presence of other species. Larger amounts of sulfate radicals were scavenged by soil-derived HS than other types of HS because soil-derived HS were composed of larger molecules than other types of HS. The fluorescence regional integration volume for HS reacted with persulfate linearly correlated with persulfate consumption. Decreases in the fluorescence regional integration value could be used to predict persulfate activation through electron transfer from HS to persulfate if the electron-donating capacity cannot be determined. Persulfate activation by HS is expected to be stoichiometrically more advantageous than conventional persulfate-Fe2+ processes when treating an aquifer containing large amounts of electron-rich HS.

Field-scale investigation of nanoscale zero-valent iron (NZVI) injection parameters for enhanced delivery of NZVI particles to groundwater.

The effects of the injection parameters on delivery of nanoscale zero-valent iron (NZVI) to contaminated groundwater were investigated. The first two NZVI injections (gravity injection at low flow rates) resulted in NZVI being poorly mobile and gave total cumulative mass recoveries at the monitoring wells of 1.07%-2.43%. NZVI reached some wells (KDMW-3, MW-2, MW-4, and MW-7) earlier than the bromide tracer. The dominant travel directions for NZVI and the bromide tracer were very different. The NZVI transport characteristics suggested that targeted NZVI delivery requires preferential groundwater flow paths and local heterogeneity to be considered. In the gravity injection tests, the maximum NZVI concentrations and cumulative NZVI mass recoveries in the wells decreased markedly as the injected NZVI concentration and dose increased. In the third and fourth tests, in which NZVI was injected under pressure at high flow rates, NZVI was effectively delivered to the wells despite the injected NZVI concentration and dose being high. Relatively high cumulative mass recoveries of 26.0% and 74.5% were found for the third and fourth injections, respectively. Controlling the flow rate (pressure) and NZVI concentration and dose simply and effectively controlled NZVI mobility in the groundwater. The colloidal and electrostatic characteristics of the NZVI particles were monitored and modeled, and the results indicated that NZVI particles without Derjaguin-Landau-Verwey-Overbeek energy barriers were successfully delivered to the target zone and that decreased magnetic attractive forces between NZVI particles caused by iron corrosion probably decreased the degree of NZVI particle aggregation and therefore contributed to NZVI being delivered to the target zone.

Electrochemical degradation of ibuprofen using an activated-carbon-based continuous-flow three-dimensional electrode reactor (3DER).

We developed a continuous-flow three-dimensional electrode reactor (3DER) to remove ibuprofen (IBP) from water. The effects of the operating parameters on the 3DER performance were investigated. The 3DER was constructed by filling a conventional two-dimensional electrode reactor with granular activated carbon, which acted as particle electrodes. The IBP removal efficiency of the 3DER was 98% in 4 h, which was 2.5 times higher than the removal efficiency for the two-dimensional electrode reactor. IBP removal kinetics tests indicated that the current density (1-20 mA/cm2) correlated better than the other operating parameters with the first-order rate constant (k). The flow rate affected the IBP removal kinetics to a small degree. Chloride and sulfate supporting electrolyte concentrations between 17 and 100 mM affected the IBP removal kinetics in opposite ways. Increasing the chloride concentration increased k, but increasing the sulfate concentration decreased k. Radical quenching experiments indicated that much more IBP degradation occurred through both indirect and direct oxidation mechanisms in the 3DER than in the two-dimensional electrode reactor. The particle electrodes caused hydroxyl radicals to form when the 3DER treatment was started, but the particle electrodes later acted as third electrodes and favored direct oxidation of IBP.

Effects of the formation of reactive chlorine species on oxidation process using persulfate and nano zero-valent iron.

The chloride ion (Cl-) is a matrix ion that plays crucial roles in radical-based oxidation processes used to treat brackish or saline water. Here, the effects of the formation of reactive chlorine species on the performance of and reaction mechanisms involved in persulfate/nano zero-valent iron process were evaluated by investigating the reaction kinetics and performing reactive species scavenging tests. The phenol oxidation rate increased markedly in the early reaction stage in the presence of 25-200 mM of Cl-. This was because excess sulfate radicals (SO4-) reacted with Cl- to produce short-lived reactive chlorine species such as Cl and Cl2- rather than being scavenged by Fe2+ or other SO4-. The reactive chlorine species caused OH to form through radical propagation reactions. The total numbers of reactive species involved in phenol oxidation were higher at brackish to weakly saline Cl- concentrations than at lower and higher Cl- concentrations. At high Cl- concentrations (>400 mM), the phenol oxidation rate decreased because most of the SO4- reacted with Cl- to give large amounts of weaker oxidants such as Cl2- and HOCl. Acceleration of Fe corrosion by Cl- negligibly affected the persulfate/nano zero-valent iron oxidation process.

Mechanisms of electro-assisted persulfate/nano-Fe0 oxidation process: Roles of redox mediation by dissolved Fe.

Mechanisms involved in an electrochemically assisted oxidation process using persulfate and nanosized zero-valent iron (NZVI) were elucidated. Initially, Fe0 acted as a source of Fe2+ to activate the persulfate, then Fe2+/Fe3+ redox mediation between cathode and persulfate played a decisive role in persulfate activation at a current density low enough not to inhibit Fe0 corrosion. An excessive current density which resulted in a low cathodic potential limited Fe0 corrosion and therefore limited the supply of dissolved Fe to activate the persulfate. Direct oxidation of phenol at the anode therefore became more important under the excessive current density than oxidation by sulfate radicals. At a low current density, Fe0 in the NZVI particles was completely transformed into iron (oxyhydr)oxides such as ferrihydrite, lepidocrocite, and magnetite. Fe0 was transformed into Fe2+ little when the current density was high. Increasing the current density increased the energy cost by increasing the amount of electrical energy dissipated in side reactions that decreased sulfate radical formation. The results indicated that a low current density can generally be used to give a high reaction rate and a high energy efficiency and that a high current density can be used when the NZVI particles need to be preserved.

Carbonation/granulation of mine tailings using a MgO/ground-granule blast-furnace-slag binder.

A carbonation/granulation process for treating mine tailings using a MgO/ground-granule blast-furnace-slag (GGBS) binder was developed. The materials were mixed and granules produced using a granulator, then the granules were cured in a CO2 atmosphere. The optimum granulator rotation speed and retention time were 60 rpm and 7 min, respectively. The binder composition MgO0.5GGBS0.5 and binder: mine tailings ratio 3:10 gave the strongest granules. Carbonation generally increased the granule strength, but different CO2 concentrations, between 0.04% and 100%, changed the granule strength to different degrees. Granules cured in 20% CO2 for 28 d had a strength of 4.71 MPa, which was higher than the strengths of granules cured in other CO2 concentrations and of granules produced using Portland cement. The granules had relatively high CO2 storage capacities of 0.157-0.167 kg CO2/kg binder and good acid-neutralizing capacities (higher than the acid-neutralizing capacity of granules produced using Portland cement). The strength of the granules cured in 20% CO2 for 28 d was probably mainly attributed to the formation of hydromagnesite during carbonation. The hydromagnesite contributed dense and connected structures within the granules. The granules produced show great potential for use as aggregates for reclamation work and backfilling in mining areas.

Reciprocal influences of dissolved organic matter and nanosized zero-valent iron in aqueous media.

We investigated concurrent effects between nano-sized zero-valent iron (NZVI) and dissolved organic matter (DOM). Specific UV absorbance of DOM revealed that aromatic/hydrophobic moieties of DOM were bounded to NZVI surfaces. The DOM fluorescence emission peak shifted toward lower wavelength after NZVI exposure, which indicated removal of aromatic DOM fractions. This blue shift of the emission peak also attributes to the reduction of electron acceptors through NZVI-DOM charge transfer complexes. High molecular weight (103-104 Da) DOM fractions, which are suspected to be both aromatic and hydrophobic, were removed. X-ray absorption spectroscopy (XAS) elucidated that Fe(0) content in the 30-d aged NZVI in the presence of DOM (61.6%) was substantially higher than that in the absence of DOM (25.0%). Corrosion and oxidation of NZVI were mitigated due to interruption of electron transfer by surface bounded DOM and stabilization of Fe(II) by Fe-DOM complexes. The XAS also revealed that the evolution of the iron (oxyhydr)oxide shell of NZVI was significantly altered by complexed aromatic DOM.

Activation of Persulfate by Nanosized Zero-Valent Iron (NZVI): Mechanisms and Transformation Products of NZVI.

The mechanisms involved in the activation of persulfate by nanosized zero-valent iron (NZVI) were elucidated and the NZVI transformation products identified. Two distinct reaction stages, in terms of the kinetics and radical formation mechanism, were found when phenol was oxidized by the persulfate/NZVI system. In the initial stage, lasting 10 min, Fe0(s) was consumed rapidly and sulfate radicals were produced through activation by aqueous Fe2+. The second stage was governed by Fe catalyzed activation in the presence of aqueous Fe3+ and iron (oxyhydr)oxides in the NZVI shells. The second stage was 3 orders of magnitude slower than the initial stage. An electron balance showed that the sulfate radical yield per mole of persulfate was more than two times higher in the persulfate/NZVI system than in the persulfate/Fe2+ system. Radicals were believed to be produced more efficiently in the persulfate/NZVI system because aqueous Fe2+ was supplied slowly, preventing sulfate radicals being scavenged by excess aqueous Fe2+. In the second stage, the multilayered shell conducted electrons, and magnetite in the shell provided electrons for the activation of persulfate. Iron speciation analysis (including X-ray absorption spectroscopy) results indicated that a shrinking core/growing shell model explained NZVI transformation during the persulfate/NZVI process.

Effects of oxidants on in situ treatment of a DNAPL source by nanoscale zero-valent iron: A field study.

This study aimed to evaluate the efficiency of a nanoscale zero-valent iron (NZVI)-based treatment process for an aquifer contaminated with trichloroethylene (TCE) in which TCE in dense non-aqueous phase liquid (DNAPL) form was also present. The study further investigated the effects of site oxidants on the reactivity and lifetime of NZVI. The injection of 30 kg of NZVI into the site successfully removed 95.7% of TCE in the groundwater within the first 60 days without producing chlorinated intermediates. The chloride balance analysis estimated that 2214 g of TCE was removed and confirmed the presence of DNAPL TCE. The oxidation of NZVI particles by nitrate, dissolved oxygen (DO), and TCE consumed 29.5%, 13.5%, and 14.3% of the Fe(0) initially present, respectively, over 60 days. Thus, nitrate was identified as the priority among groundwater oxidants. The reactive lifetime of NZVI at the site was found to be at least 103 days, based on the monitoring of TCE, DO, and nitrate concentrations, oxidation-reduction potential (ORP), and the residual Fe(0) content of the NZVI particles. Solid samples that were retrieved from the site on the 165th day still contained substantial amounts of Fe(0), occupying up to 21.9% of the total mass, and retained considerable reactivities towards TCE. This indicates that the NZVI particles aged more than 5 months at the site can potentially be reused for TCE reduction even after extensive corrosion of Fe(0) has occurred.

The effects of self-mobilization techniques for the sciatic nerves on physical functions and health of low back pain patients with lower limb radiating pain.

[Purpose] This study aimed to examine the effects of self-mobilization techniques for the sciatic nerves on the quality of life in patients with chronic low back pain in the lower limbs accompanied by radiating pain. [Subjects and Methods] The subjects were divided into two groups: a group receiving of lumbar segmental stabilization exercise training including sciatic nerve mobilization techniques, which included 8 males and 7 females, and a group receiving lumbar segmental stabilization exercise training, which included 8 males and 7 females. [Results] There were statistically significant differences in comparison of measurement results between the groups before and after the intervention. [Conclusion] Application of mobilization techniques for the sciatic nerves may promote healing of the soft tissues by stimulating the functions of the nervous system to improve nervous system adaptability and decrease sensitivity, helping to alleviate the symptoms.

Influence of the application of inelastic taping on shoulder subluxation and pain changes in acute stroke patients.

[Purpose] The purpose of this study was to investigate the impact on the shoulder joints of performing inelastic taping and bed physical therapy for acute stroke. [Subjects and Methods] The intervention was conducted for eight weeks with an experimental group of 18 stroke patients who received bed physical therapy and inelastic taping and a control group of 18 stroke patients who received only bed physical therapy. [Results] After the intervention, the subluxation degree of the experimental group, which received bed physical therapy and inelastic taping, was found to be significantly different from that of the control group, which received only bed physical therapy. [Conclusion] In conclusion, the application of inelastic taping for acute stroke patients was confirmed to be effective at reducing shoulder subluxation and pain, and was confirmed to be a good physical therapy intervention, based on its efficacy.

Development of an MgO-based binder for stabilizing fine sediments and storing CO2.

An MgO-based binder was developed that could stabilize fine dredged sediments for reuse and store CO2. Initially, a binder consisting of fly ash (FA) and blast furnace slag (BFS) was developed by using alkaline activators such as KOH, NaOH, and lime. The FA0.4-BFS0.6 binder (mixed at a FA-to-BFS weight ratio of 4:6) showed the highest compressive strength of 10.7 MPa among FA/BFS binders when 5 M KOH was used. When lime (L) was tested as an alkaline activator, the strength was comparable with those obtained when KOH or NaOH was used. The L0.1-(FA0.4BFS0.6)0.9 binder (10 % lime mixed with the FA/BFS binder) showed the highest strength of 11.0 MPa. Finally, by amending this L0.1-(FA0.4BFS0.6)0.9 binder with MgO, a novel MgO-based binder (MgO0.5-(L0.1-(FA0.4BFS0.6)0.9) 0.5) was developed, which demonstrated the 28th day strength of 11.9 MPa. The MgO-based binder was successfully applied to stabilize a fine sediment to yield a compressive strength of 4.78 MPa in 365 days, which was higher than that obtained by the Portland cement (PC) system (3.22 MPa). Carbon dioxide sequestration was evidenced by three observations: (1) the decrease in pH of the treated sediment from 12.2 to 11.0; (2) the progress of the carbonation front inward the treated sediment; and (3) the presence of magnesium carbonates. The thermogravimetric analysis (TGA) results showed that 67.2 kg of CO2 per ton of the treated sediment could be stored under the atmospheric condition during 1 year.

Comparison of physical function according to the lumbar movement method of stabilizing a patient with chronic low back pain.

[Purpose] The purpose of this study was to examine the changes caused by lumbar stabilization exercises in chronic low back pain patients. [Subjects and Methods] Swiss ball exercise regimen group and sling exercise regimen group exercised for 30 minutes a day, 5 days a week, for 12 weeks. The control group was to continue performing their usual daily living activities. [Results] We obtained significant results in both the Swiss ball and sling exercise groups, but not in the control group. The best effect was obtained in the sling exercise group. [Conclusion] The Oswestry Low Back Pain Disability Index and visual pain scale scores of the patients with low back pain decreased in both the Swiss ball exercise group and the sling exercise group, and these patients experienced an increase in waist isometric muscular strength after 12 weeks of exercise compared with those doing no exercise (the control group).

The effects of gluteus muscle strengthening exercise and lumbar stabilization exercise on lumbar muscle strength and balance in chronic low back pain patients.

[Purpose] The aim of this study was to examine the effects of exercise to strengthen the muscles of the hip together with lumbar segmental stabilization exercise on the lumbar disability index, lumbar muscle strength, and balance. [Subjects and Methods] This study randomly and equally assigned 40 participants who provided written consent to participate in this study to a lumbar segmental stabilization exercise plus exercise to strengthen the muscles of the gluteus group (SMG + LES group) and a lumbar segmental stabilization exercise group. [Results] Each evaluation item showed a statistically significant effect. [Conclusion] Clinical application of exercise in this study showed that lumbar segmental stabilization exercise plus exercise to strengthen the muscles of the gluteus resulted in a greater decrease in low back pain disability index and increase in lumbar muscle strength and balance ability than lumbar segmental stabilization exercise in chronic low back pain patients receiving the exercise treatments during the same period.

Effect of anions and humic acid on the performance of nanoscale zero-valent iron particles coated with polyacrylic acid.

Effects of anions (NO3(-), HCO3(-), Cl(-), SO4(2-)) and humic acid on the reactivity and core/shell chemistries of polyacrylic acid-coated nanoscale zero-valent iron (PAA-NZVI) and inorganically modified NZVI (INORG-NZVI) particles were investigated. The reactivity tests under various ion concentrations (0.2-30mN) revealed the existence of a favorable molar ratio of anion/NZVI that increased the reactivity of NZVI particles. The presence of a relatively small amount of humic acid (0.5mgL(-1)) substantially decreased the INORG-NZVI reactivity by 76%, whereas the reactivity of PAA-NZVI decreased only by 12%. The XRD and TEM results supported the role of the PAA coating of PAA-NZVI in impeding the oxidation of the Fe(0) core by groundwater solutes. This protective role provided by the organic coating also resulted in a 2.3-fold increase in the trichloroethylene (TCE) reduction capacity of PAA-NZVI compared to that of INORG-NZVI in the presence of anions/humic acid. Ethylene and ethane were simultaneously produced as the major reduction products of TCE in both NZVI systems, suggesting that a hydrodechlorination occurred without the aid of metallic catalysts. The PAA coating, originally designed to improve the mobility of NZVI, enhanced TCE degradation performances of NZVI in the presence of anions and humic acid.

Comparison of the Effects of Hollowing and Bracing Exercises on Cross-sectional Areas of Abdominal Muscles in Middle-aged Women.

[Purpose] The purpose of this study was to examine the effects of hollowing and bracing exercises on cross-sectional areas of abdominal muscles. [Subjects] Thirty healthy female adults participated in this study. The exclusion criteria were orthopedic or neurologic diseases. [Methods] The subjects of this study were assigned randomly to one of two groups, each with 15 people. Each group performed a 60-minute exercise program, one performed a bracing exercise, and the other performed a hollowing exercise, with both groups performing the exercise three times a week for six weeks. [Results] The changes in cross-sectional areas after the bracing exercise showed statistically significant differences in the left rectus abdominis and both internal and external obliques. The changes in cross-sectional areas after the hollowing exercise showed statistically significant differences in the left and right transversus abdominis and left rectus abdominis. [Conclusion] Performing bracing exercises rather than hollowing exercises is more effective for activating the abdominal muscles.

Effects of vibratory stimulations on maximal voluntary isometric contraction from delayed onset muscle soreness.

[Purpose] The aim of this study was to investigate the effect of vibratory stimulation on maximal voluntary isometric contraction (MVIC) from delayed onset muscle soreness (DOMS). [Subjects] Sixty healthy adults participated in this study. The exclusion criteria were orthopedic or neurologic disease. [Methods] The researchers induced DOMS in the musculus extensor carpi radialis longus of each participant. Subjects in the control group received no treatment. The ultrasound group received ultrasound treatment (intensity, 1.0 W/cm(2;) frequency 1 MHz; time, 10 minutes). The vibration group received vibration stimulation (frequency, 20 MHz; time, 10 minutes). Maximal voluntary isometric contraction (MVIC) was recorded at baseline, immediately after exercise, and 24, 48, and 72 hours after exercise. [Results] MVIC measurements showed statistically significant differences in the vibration group compared with the control group. [Conclusion] Vibratory stimulation had a positive effect on recovery of muscle function from DOMS.