• Bulletin of the Korean Mathematical Society
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• v.59 no.3
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• pp.781-787
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• 2022

In this paper, we show that under certain conditions the Wedderburn decomposition of a finite semisimple group algebra 𝔽_qG can be deduced from a subalgebra 𝔽_q(G/H) of factor group G/H of G, where H is a normal subgroup of G of prime order P. Here, we assume that q = p^r for some prime p and the center of each Wedderburn component of 𝔽_qG is the coefficient field 𝔽_q.

• Kyungpook Mathematical Journal
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• v.62 no.4
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• pp.769-772
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• 2022

Given a prime number p and a natural number m not divisible by p, we propose the problem of finding the smallest number r₀ such that for r ≥ r₀, every group G of order p^rm has a non-trivial normal p-subgroup. We prove that we can explicitly calculate the number r₀ in the case where every group of order p^rm is solvable for all r, and we obtain the value of r₀ for a case where m is a product of two primes.

• Archives of Plastic Surgery
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• v.47 no.5
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• pp.444-450
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• 2020

Background Fingertip injuries are the most common type of traumatic injury treated at emergency departments and require prompt and adequate interventions for favorable wound survival outcomes. Hyperbaric oxygen (HBO₂) therapy is well known for its many positive effects on wound healing. We hypothesized that treatment with HBO₂ would improve the graft survival outcomes of amputated fingertip injuries treated with composite grafts. Methods This retrospective observational study included fingertip amputations that were treated between January 2013 and December 2017. A conventional group and an HBO₂ therapy group were statistically compared to evaluate the effect of HBO₂ treatment. Graft survival was categorized as either success or failure. Results Among 55 cases (digits), 34 digits were conventionally treated, while 21 digits were treated with HBO₂. No statistically significant differences were observed between the groups with regard to general characteristics. Among patients with guillotine-type injuries, the composite graft success rate was statistically significantly higher in the group that received HBO₂ therapy than in the conventional group (P=0.0337). Overall, the HBO₂ group also demonstrated a statistically significantly shorter healing time than the conventional group (P=0.0075). As such, HBO₂ treatment facilitates composite graft survival in cases of fingertip injury. Conclusions HBO₂ treatment was associated with an increased composite graft survival rate in guillotine-type fingertip injuries and reduced the time required for grafts to heal.

• Journal of Sensor Science and Technology
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• v.29 no.5
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• pp.360-364
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• 2020

In this study, the colorimetric sensor, polyester (PET) fabric dyed with lead (II) acetate (Pb(C₂H₃O₂)₂), was fabricated and characterized for the detection of the hydrogen sulfide (H₂S). The surface morphology of the fabric was determined using scanning electron microscope and energy-dispersive X-ray spectroscopy. The optical properties of the fabric were evaluated by measuring the variation in the blue value of an RGB sensor. The fabric showed a significant color change, high linearity (R² : 0.98256), and fast response time (< 1.0 s) when exposed to H₂S. This is because the sensor is highly porous and permeable to the gas. The fabric can not only be used as a hydrogen sulfide sensor but also be used to detect and prevent H₂S influx using sticky tape on pipelines.

• Journal of Sensor Science and Technology
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• v.31 no.5
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• pp.337-342
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• 2022

Hydrogen (H₂) gas is widely preferred for use as a renewable energy source owing to its characteristics such as environmental friendliness and a high energy density. However, H₂ can easily reverse or explode due to minor external factors. Therefore, H₂ gas monitoring is crucial, especially when the H₂ concentration is close to the lower explosive limit. In this study, metal oxide materials and their p-n heterojunctions were synthesized by a hydrothermal-assisted dip-coating method. The synthesized thin films were used as sensing materials for H₂ gas. When the H₂ concentration was varied, all metal oxide materials exhibited different gas sensitivities. The performance of the metal oxide gas sensor was analyzed to identify parameters that could improve the performance, such as the choice of the metal oxide material, effect of the p-n heterojunctions, and operating temperature conditions of the gas sensor. The experimental results demonstrated that a CuO/ZnO gas sensor with a p-n heterojunction exhibited a high sensitivity and fast response time (134.9% and 8 s, respectively) to 5% H₂ gas at an operating temperature of 300℃.

• Korean Journal of Veterinary Research
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• v.43 no.2
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• pp.171-180
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• 2003

Certain hexavalent chromium compounds when administered via inhalation have the potential to induce lung injury in human and experimental animals. In present study, the inhalation effect of hexavalent chromium on morphological change and weight change of rat organ were investigated. Rats were exposed to hexavalent chromium ($Na_2CrO_4{\cdot}4H_2O$) at concentration of $0.36mg/m^3$ (group 1), $1.8mg/m^3$ (group 2), ascorbic acid and $1.8mg/m^3$ (group 3) and filtered air (group 0, control group) for I week, 2 weeks and 3 weeks. The weight of lung and kidney in group 2 and group 3 significantly higher than in control group at same exposure period. The epithilial cells of bronchiole in group 1, 2, 3 were more flatten than group 0. In the lung, the number of macrophage was significantly increased and morphologically changed macrophages were observed in group 1, 2, 3. The morphological change of the lung did not significant between group 2 and group 3, however, in group 1 was milder than in group 2 and group 3. The severity of morphological change were depend on exposure period in the lung. The morphological changes by hexavalent chromium of the liver and kidney were also observed These results suggest that inhalation of hexavalent chromium effects on not only respiratory organ, but also the liver and the kidney via blood stream.

• Bulletin of the Korean Chemical Society
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• v.27 no.1
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• pp.35-36
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• 2006

• The Journal of Advanced Prosthodontics
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• v.12 no.5
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• pp.291-298
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• 2020

PURPOSE. The aim of this study is to evaluate the influence of repeated surface treatments on wettability and surface roughness for zirconia surface and bond strength of zirconia-based ceramics to resin cement. MATERIALS AND METHODS. Seventy blocks (10 × 10 × 3 mm) of zirconia-based ceramics were fabricated and divided into two groups according to the surface treatments: (A) 110 ㎛ Al₂O₃ airborne-particle abrasion and (R) 110 ㎛ silica modified Al₂O₃ airborne-particle abrasion. At stage 2, each group was subdivided into 5 groups according to the surface retreatments: (a) 110 ㎛ Al₂O₃ airborne-particle abrasion, (r) 110 ㎛ silica modified Al₂O₃ airborne-particle abrasion, (D) diamond bur, (Da) diamond bur + 110 ㎛ Al₂O₃ airborne-particle abrasion, and (Dr) diamond bur + 110 ㎛ silica modified Al₂O₃ airborne-particle abrasion. Cylinders of self-adhesive resin cement were cemented onto each treated ceramic surface and subjected to micro-shear bond strength test. Additional specimens were prepared for roughness and wettability analyses. The data were subjected to t-test and One-way ANOVA followed by Tukey's post hoc test (α=.05). RESULTS. At stage 1, group R presented higher bond strength values than group A (P=.000). There was a statistically significant increase of bond strength at stage 2 for group A (P=.003). The diamond bur influenced the surface roughness, increasing the values (P=.023). Group R provided better wettability. Regardless of the applied surface treatment, most of failures were adhesive. CONCLUSION. The combination of application and reapplication of Rocatec Plus showed the best results of bond strength. Surface retreatment and recementation might be an indicated clinical strategy.

• Tuberculosis and Respiratory Diseases
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• v.84 no.1
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• pp.55-66
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• 2021

Background: Particulate matter 10 (PM₁₀; airborne particles <10 ㎛) inhalation has been demonstrated to induce airway and lung diseases. In this study, we investigate the effects of PM₁₀ inhalation on RNA expression in lung tissues using a murine model. Methods: Female BALB/c mice were affected with PM₁₀, ovalbumin (OVA), or both OVA and PM₁₀. PM₁₀ was administered intranasally while OVA was both intraperitoneally injected and intranasally administered. Treatments occurred 4 times over a 2-week period. Two days after the final challenges, mice were sacrificed. Full RNA sequencing using lung homogenates was conducted. Results: While PM₁₀ did not induce cell proliferation in bronchoalveolar fluid or lead to airway hyper-responsiveness, it did cause airway inflammation and lung fibrosis. Levels of interleukin 1β, tumor necrosis factor-α, and transforming growth factor-β in lung homogenates were significantly elevated in the PM₁₀-treated group, compared to the control group. The PM₁₀ group also showed increased RNA expression of Rn45a, Snord22, Atp6v0c-ps2, Snora28, Snord15b, Snora70, and Mmp12. Generally, genes associated with RNA splicing, DNA repair, the inflammatory response, the immune response, cell death, and apoptotic processes were highly expressed in the PM₁₀-treated group. The OVA/PM₁₀ treatment did not produce greater effects than OVA alone. However, the OVA/PM₁₀-treated group did show increased RNA expression of Clca1, Snord22, Retnla, Prg2, Tff2, Atp6v0c-ps2, and Fcgbp when compared to the control groups. These genes are associated with RNA splicing, DNA repair, the inflammatory response, and the immune response. Conclusion: Inhalation of PM₁₀ extensively altered RNA expression while also inducing cellular inflammation, fibrosis, and increased inflammatory cytokines in this murine mouse model.

• Journal of the Chungcheong Mathematical Society
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• v.36 no.4
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• pp.289-296
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• 2023

When G is an abelian group, we use the notation M(G, n) to denote the Moore space. The space X is the wedge product space of Moore spaces, given by X = M(ℤ_q, n+ 2) ∨ M(ℤ_q, n+ 1) ∨ M(ℤ_q, n). We determine the self-homotopy classes group [X, X] and the self-homotopy equivalence group 𝓔(X). We investigate the subgroups of [M_j , M_k] consisting of homotopy classes of maps that induce the trivial homomorphism up to (n + 2)-homotopy groups for j ≠ k. Using these results, we calculate the subgroup 𝓔^dim_#(X) of 𝓔(X) in which all elements induce the identity homomorphism up to (n + 2)-homotopy groups of X.