• Korean Journal of Radiology
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• v.23 no.2
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• pp.218-225
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• 2022

Objective: This study aimed to explore the feasibility of functional evaluation of the lateral pterygoid muscle (LPM) using diffusion tensor imaging (DTI) in patients with temporomandibular joint disorders (TMDs). Materials and Methods: A total of 119 patients with TMD (23 male and 96 female; mean age ± standard deviation, 41 ± 15 years; 58 bilateral and 61 unilateral involvements for a total of 177 joints) and 20 healthy volunteers (9 male and 11 female; 40 ± 13 years; 40 joints) were included in this prospective study. Based on DTI of the jaw in the resting state, the diffusion parameters, apparent diffusion coefficient (ADC), fractional anisotropy (FA), λ1, λ2, and λ3 of the superior and inferior heads of the LPM (SHLPM and IHLPM) were measured. Patients with TMD with normal disc position (ND), anterior disc displacement with reduction (ADWR), and anterior disc displacement without reduction (ADWOR) were compared. Results: Patients with TMD overall, and ADWR and ADWOR subgroups had significantly higher ADC, λ1, λ2, and λ3 in both the SHLPM and IHLPM than those in volunteers (p < 0.05 for all), whereas the ND subgroup only had significantly higher ADC and λ1 (p < 0.001). Meanwhile, significant differences in FA in the SHLPM and IHLPM were found between volunteers and ADWOR (p = 0.014 and p = 0.037, respectively). Among the three TMD subgroups, except for λ3 and FA in the ADWR subgroup, ADWR and ADWOR subgroups had significantly higher ADC, λ1, λ2, and λ3 and lower FA than those in the ND group (p < 0.050). There was no significant difference in diffusion variables between ADWR and ADWOR. In ADWOR, the osteoarthritis group had significantly higher λ3 and lower FA values in the IHLPM than those in the non-osteoarthritis group. Conclusion: DTI successfully detected functional changes in the LPM in patients with TMD. The unsynchronized diffusivity changes in the LPM in different subgroups of TMD signified the possibility of using diffusion parameters as indicators to identify the severity of LPM hyperfunction at various stages of TMD.

• Journal of the Korean Electrochemical Society
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• v.23 no.2
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• pp.25-38
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• 2020

Photoelectrochemical water splitting has been considered as the most promising technology for generating hydrogen energy. Transition metal dichalcogenide (TMD) compounds have currently attracted tremendous attention due to their outstanding ability towards the catalytic water-splitting hydrogen evolution reaction (HER). Herein, we report the synthesis method of various transition metal dichalcogenide including MoS₂, MoSe₂, WS₂, and WSe₂ nanosheets as excellent catalysts for solar-driven photoelectrochemical (PEC) hydrogen evolution. Photocathodes were fabricated by growing the nanosheets directly onto Si nanowire (NW) arrays, with a thickness of 20 nm. The metal ion layers were formed by soaking the metal chloride ethanol solution and subsequent sulfurization or selenization produced the transition metal chalcogenide. They all exhibit excellent PEC performance in 0.5 M H₂SO₄; the photocurrent reaches to 20 mA cm^-2 (at 0 V vs. RHE) and the onset potential is 0.2 V under AM1.5 condition. The quantum efficiency of hydrogen generation is avg. 90%. The stability of MoS₂ and MoSe₂ is 90% for 3h, which is higher than that (80%) of WS₂ and WSe₂. Detailed structure analysis using X-ray photoelectron spectroscopy for before/after HER reveals that the Si-WS₂ and Si-WSe₂ experience more oxidation of Si NWs than Si-MoS₂ and Si-MoSe₂. This can be explained by the less protection of Si NW surface by their flake shape morphology. The high catalytic activity of TMDs should be the main cause of this enhanced PEC performance, promising efficient water-splitting Si-based PEC cells.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.292-292
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• 2016

Transition metal dichalcogenides (TMDs) with a two-dimensional layered structure have been considered highly promising materials for next-generation flexible, wearable, stretchable and transparent devices due to their unique physical, electrical and optical properties. Recent studies on TMD devices have focused on developing a suitable doping technique because precise control of the threshold voltage ($V_{TH}$) and the number of tightly-bound trions are required to achieve high performance electronic and optoelectronic devices, respectively. In particular, it is critical to develop an ultra-low level doping technique for the proper design and optimization of TMD-based devices because high level doping (about $10^{12}cm^{-2}$) causes TMD to act as a near-metallic layer. However, it is difficult to apply an ion implantation technique to TMD materials due to crystal damage that occurs during the implantation process. Although safe doping techniques have recently been developed, most of the previous TMD doping techniques presented very high doping levels of ${\sim}10^{12}cm^{-2}$. Recently, low-level n- and p-doping of TMD materials was achieved using cesium carbonate ($Cs_2CO_3$), octadecyltrichlorosilane (OTS), and M-DNA, but further studies are needed to reduce the doping level down to an intrinsic level. Here, we propose a novel DNA-based doping method on $MoS_2$ and $WSe_2$ films, which enables ultra-low n- and p-doping control and allows for proper adjustments in device performance. This is achieved by selecting and/or combining different types of divalent metal and trivalent lanthanide (Ln) ions on DNA nanostructures. The available n-doping range (${\Delta}n$) on the $MoS_2$ by Ln-DNA (DNA functionalized by trivalent Ln ions) is between $6{\times}10^9cm^{-2}$ and $2.6{\times}10^{10}cm^{-2}$, which is even lower than that provided by pristine DNA (${\sim}6.4{\times}10^{10}cm^{-2}$). The p-doping change (${\Delta}p$) on $WSe_2$ by Ln-DNA is adjusted between $-1.0{\times}10^{10}cm^{-2}$ and $-2.4{\times}10^{10}cm^{-2}$. In the case of Co-DNA (DNA functionalized by both divalent metal and trivalent Ln ions) doping where $Eu^{3+}$ or $Gd^{3+}$ ions were incorporated, a light p-doping phenomenon is observed on $MoS_2$ and $WSe_2$ (respectively, negative ${\Delta}n$ below $-9{\times}10^9cm^{-2}$ and positive ${\Delta}p$ above $1.4{\times}10^{10}cm^{-2}$) because the added $Cu^{2+}$ ions probably reduce the strength of negative charges in Ln-DNA. However, a light n-doping phenomenon (positive ${\Delta}n$ above $10^{10}cm^{-2}$ and negative ${\Delta}p$ below $-1.1{\times}10^{10}cm^{-2}$) occurs in the TMD devices doped by Co-DNA with $Tb^{3+}$ or $Er^{3+}$ ions. A significant (factor of ~5) increase in field-effect mobility is also observed on the $MoS_2$ and $WSe_2$ devices, which are, respectively, doped by $Tb^{3+}$-based Co-DNA (n-doping) and $Gd^{3+}$-based Co-DNA (p-doping), due to the reduction of effective electron and hole barrier heights after the doping. In terms of optoelectronic device performance (photoresponsivity and detectivity), the $Tb^{3+}$ or $Er^{3+}$-Co-DNA (n-doping) and the $Eu^{3+}$ or $Gd^{3+}$-Co-DNA (p-doping) improve the $MoS_2$ and $WSe_2$ photodetectors, respectively.

• Journal of Oral Medicine and Pain
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• v.31 no.2
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• pp.155-165
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• 2006

The purpose of this study was to evaluate treatment outcome and prognosis of the patients with orofacial pain disorders who visited for treatment in the Department of Oral Medicine, Dankook University Dental Hospital from January 2002 to December 2004. Orofacial pain disorders were categorized into TMD(myogenous, arthrogenous and muscle-joint combined TMDs), neuropathic pain disorder, oral soft tissue disease and complex condition simultaneously having more and two aforementioned categories and treatment period, method and treatment outcome were evaluated. The results of this study were as follows; 1. Average longevity of treatment period was the longest in the neuropathic pain, followed by soft tissue disease, complex conditions, arthrogenous TMD, muscle-joint combined TMD and myogenous TMD in order. 2. When treatment methods were largely categorized into pharmacologic, physical and oral appliance therapy, pharmacologic therapy was used the most frequently for the patients with neuropathic pain or oral soft tissue diseases, oral appliance therapy for those with arthrogenous TMD and physical therapy for those with myogenous TMD. 3. Of physical therapeutic methods used in our clinic, EAST and microwave was employed the most frequently in the patients with myogenous TMD, ultrasound for those with arthogenous TMD and LLLT for those with neuropathic pain or oral soft tissue disease. 4. In comparison with change of pain after treatment, there existed a tendency that pain from neuropathic pain disorders persisted while pain from TMD was getting better or totally disappeared. 5. Concerning the change of mouth opening range in the TMD subgroups, there was no significant difference among the subgroups but significant difference existed among opening ranges, indicating comfortable maximum mouth opening increased the most following treatment. Improvement of active range of mouth opening was the most considerable in those with disc displacement without reduction. It can be said on the basis of the findings from this study that various treatments currently used for the orofacial pain showed good results with TMD in regards with pain control and improvement of function, suggestive of favorable prognosis, while neuropathic pain or soft tissue disease was the clinical conditions difficult to resolve, requiring a long and persistent treatment.

• Journal of Oral Medicine and Pain
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• v.36 no.4
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• pp.261-271
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• 2011

Osteoarthritis in patients with temporomandibular disorders(TMDs) induces pain, limitation of mouth opening, occlusal problems, and most commonly affects their life quality. Control method and progressive process of osteoarthritis are being extensively researched. The researchers focus on histologic changes, synovial changes, muscular and ligamental changes and observed reaction to pain. Therefore most of them developed the animal model for osteoarthritis in TMD patients. In this study, we applied several methods which induces osteoarthritis of temporomandibular joint(TMJ) in rats or mice. For locally induce osteoarthritis in TMJ, Monosodium iodoacetate(MIA) or interleukin-$1{\alpha}$(IL-$1{\alpha}$) were injected into TMJ joint space for 5 or 3 weeks. Other groups are chosen for osteoarthritis under systemic control including hormonal changes and aging. To observe cellular change, increased collagen, degenerative bony destruction and distribution of proteoglycans (PGs), safranin-O staining and Masson's trichrome staining were used.

• Journal of Oral Medicine and Pain
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• v.32 no.3
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• pp.305-318
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• 2007

To evaluate the treatment outcome after conservative treatment in patients with TMJ disc displacement which is the most common temporomandibular joint arthropathy, the subjects were chosen among the patients who presented to the Department of Oral Medicine of Pusan National University Hospital, diagnosed as TMDs and treated with conservative methods from 1994 to 2006 for 13 years. 88 patients with diagnosis of DD/cR and 60 patients with diagnosis of DD/sR were selected as the experimental group and 74 patients with diagnosis of masticatory muscle disorder (MMD) were selected as the control group. Subjective symptoms and clinical findings were investigated to evaluate and compare the subjects' status at the first visit and the last visit. The results were as follows; 1. Pain, noise, LOM and MCO measurements of DD/cR, DD/sR and MMD groups were markedly improved after conservative treatments including behavior therapy, physical therapy, medication and splint therapy. 2. At the first visit, high score of pain in MMD group, high score of noise and large MCO measurement in DD/cR group and high LOM score in DD/sR group were observed. At the last visit, high score of noise and increased MCO measurement in DD/cR group and high score of pain and LOM in DD/sR group were observed. 3. Among the patients who complained joint sound at their first visit, about 60% showed complete loss of joint sound after conservative treatment 4. DD/cR and DD/sR groups showed satisfactory outcomes after conservative treatments such as behavior therapy, physical therapy, medication and splint therapy while MMD group showed similar treatment outcome irrespective of the treatment modality used. 5. There was no difference in treatment outcomes after conservative treatments when the subjects were classified and compared according to gender, age group and chronicity. 6. MMD showed satisfactory prognosis in 10 treatments in less than 6 months while DD showed favorable prognosis in 10-20 treatments for 6 months to 2 years.