• Title/Summary/Keyword: biomaterials

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The Relationship between Physical/Mental health and life stress of college students (Focusing on department of dental laboratory technology and dental hygiene) (대학생의 신체 및 정신 건강과 생활스트레스와의 관계 (치기공과, 치위생과 대학생 중심으로))

  • Kim, Yeoun-Soo;Yu, Sang-Hui
    • Journal of Technologic Dentistry
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    • v.35 no.4
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    • pp.405-414
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    • 2013
  • Purpose: The purpose of this study was to examine the relationship of the general characteristics of health-related majors to their life expectancy scale, depression scale, health perception scale, subjective wellbeing scale, somatic symptom scale and college life stress scale. And it's also meant to analyze influential factors for their stress about college life. Methods: The subjects in this study were the students who were in the department of dental laboratory technology and the department of dental hygiene at a college located in the region of Iksan, North Jeolla Province. Data were gathered in November and December, 2012. The life expectancy scale, depression scale, health perception scale, subjective wellbeing scale, physical symptom scale, somatic symptom scale and college life stress scale of the general characteristics were analyzed by t-test and one way analyses of variance (ANOVA) and the Duncan's multiple range test at the 95% confidence level to assess the statistical significance. And stepwise multiple regression analysis was conducted to determine what factors would affect the stress of the students about college life. The data were analyzed with the windows ver. 12.0(SPSS GmbH, Germany) statistical software program. Results: Among the general characteristics, there were significant differences according to gender and age in all the variables that were life expectancy scale, depression scale, health perception scale, subjective wellbeing scale, physical symptom scale and college life stress scale. 61.3% of the students responded they slept for six hours or less, and the respondents who slept for six hours or less scored significantly statistically lower in health perception scale, subjective wellbeing scale and physical symptom scale. As for college life stress, the respondents who got depressed more often, whose subjective peace or happiness was lower, whose life expectancy was lower, who had worse physical symptoms, whose living standard was lower and whose academic year was lower were under heavier stress about their college lives. Conclusion: As the worse physical health and worse mental health(life expectancy, depression, health perception, subjective wellbeing and physical symptoms, etc.) of the college students led to heavier stress about college life, how to promote their physical health and mental health should discreetly be considered, and every necessary measure should be taken to improve their physical and mental health.

Antioxidant and Anti-inflammatory Activities of Water-soluble Extracts from Different Parts of Kojongsi Persimmon (Diospyros kaki L.) (고종시 감나무 부위별 수용성 추출물의 항산화 및 항염 활성)

  • Jeon, In Hwa;Kang, Hyun Ju;Lee, Hyun-Seo;Shin, Jun Ho;Park, Yong Gyoun;Jeong, Seung-Il;Jang, Seon Il
    • Korean Journal of Food Science and Technology
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    • v.46 no.4
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    • pp.505-510
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    • 2014
  • Kojongsi persimmon (Diospyros kaki L.) is the major cultivar of dried persimmon in Korea. The purpose of this study was to investigate the antioxidant and anti-inflammatory activities of water-soluble extracts from the calyx (PCE), peel (PPE) and leaf (PLE) of Kojongsi persimmon. PCE showed the highest total phenolic and flavonoid contents. In addition, the antioxidant activities (diphenylpicrylhydrazyl, 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid), nitric oxide and reducing power) of PCE were higher than those of PPE and PLE. Moreover, PCE, PPE and PLE significantly suppressed the production of inflammatory mediators (nitric oxide and $prostaglandinE_2$) and pro-inflammatory cytokines (tumor necrosis factor-${\alpha}$ and interluekin-$1{\beta}$) by lipopolysaccharide-stimulated RAW 264.7 cells in a dose-dependent manner. PCE showed the highest anti-inflammatory activity. Thus, these results suggest that the calyx of Kojongsi persimmon may be highly valuable as a natural product owing to its high-quality functional components as well as its-antioxidant, ant-iinflammatory activities.

REAL-TIME MEASUREMENT OF DENTINAL TUBULAR FLUID FLOW DURING AND AFTER AMALGAM AND COMPOSITE RESTORATIONS (아말감과 복합레진의 수복 과정과 수복 후 발생하는 상아세관액 흐름의 실시간 측정)

  • Kim, Sun-Young;Cho, Byeong-Hoon;Baek, Seung-Ho;Lim, Bum-Sun;Lee, In-Bog
    • Restorative Dentistry and Endodontics
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    • v.34 no.6
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    • pp.467-476
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    • 2009
  • The aim of this study was to measure the dentinal tubular fluid flow (DFF) during and after amalgam and composite restorations. A newly designed fluid flow measurement instrument was made. A third molar cut at 3 mm apical from the CEJ was connected to the flow measuring device under a hydrostatic pressure of 15 $cmH_2O$. Class I cavity was prepared and restored with either amalgam (Copalite varnish and Bestaloy) or composite (Z-250 with ScotchBond MultiPurpose: MP, Single Bond 2: SB, Clearfil SE Bond: CE and Easy Bond: EB as bonding systems). The DFF was measured from the intact tooth state through restoration procedures to 30 minutes after restoration, and re-measured at 3 and 7days after restoration. Inward fluid flow (IF) during cavity preparation was followed by outward flow (OF) after preparation, In amalgam restoration, the OF changed to IF during amalgam filling and slight OF followed after finishing. In composite restoration, application CE and EB showed a continuous OF and air-dry increased rapidly the OF until light-curing, whereas in MP and SB, rinse and dry caused IF and OF, respectively. Application of hydrophobic bonding resin in MP and CE caused a decrease in flow rate or even slight IF. Light-curing of adhesive and composite showed an abrupt IF. There was no statistically significant difference in the reduction of DFF among the materials at 30 min. 3 and 7 days after restoration (p > 0.05).

Analysis for Water Vapour Adsorption and Desorption Performance of Waste Paper-Mulberry according to Particle Size Control (폐닥나무의 입도제어에 따른 흡·방습 특성 분석)

  • Jo, Ki-Sic;Kim, Tae-Yeon;Seo, Sung-Kwan;Lee, Oh-Kyu;Chu, Yong-Sik
    • Resources Recycling
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    • v.29 no.2
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    • pp.8-17
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    • 2020
  • In this study, adsorption and desorption characteristics of pulverized waste paper-mulberry pellet and bast fiber were measured to confirm the applicability to humidity control products. Paper-mulberry powder was classified by 710-355㎛, 355-100㎛, 100-45㎛ and less than 45㎛ and used in experiment. Specific surface area increased from 1.02㎡/g to 1.35㎡/g as the particle size decreased from 710㎛ to under 45㎛. Adsorption and desorption performance decreased in the order of 355-100㎛, 710-355㎛, 100-45㎛, less than 45㎛ and bast fiber, adsorption content on each particle sizes were 141.1g/㎡, 147.1g/㎡, 135.7g/㎡, 129.0g/㎡ and desorption content were 117.2g/㎡, 123.6g/㎡, 110.2g/㎡, 93.3g/㎡. As a result, adsorption and desorption performance of paper-mulberry powder were superior to those of the bast fiber and these phenomenon can be considered that it caused by pore distribution in pellet and damage of fiber.

In Vitro Culture of Primary Testicular Stromal Cells derived from Mouse with Different Genetic Background : Optimization of Culture Temperature

  • Park, Hye Jin;Yun, Jung Im;Choi, Jung Hoon;Lee, Eunsong;Gong, Seung Pyo;Lee, Seung Tae
    • Journal of Embryo Transfer
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    • v.28 no.4
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    • pp.373-379
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    • 2013
  • Spermatogonial stem cells (SSCs) developed into sperms through spermatogenesis have been utilized as a useful tool in the field of regenerative medicine and infertility. However, a small number of highly qualified SSCs are resided in the seminiferous tubule of testis, resulted in developing effective in-vitro culture system of SSCs for solving simultaneously quantitative and qualitative problems. Presently, SSCs can be enriched on testicular stromal cells (TSCs), but there are no systematic researches about TSC culture. Therefore, we tried to optimize culture condition of TSCs derived from mouse with different strains. For these, proliferation and viability were measured and compared by culturing ICR outbred or DBA/2 inbred mouse-derived TSCs at 35 or $37^{\circ}C$. In case of ICR strain, primary TSCs cultured at $37^{\circ}C$ showed significantly higher proliferation and viability than those at $35^{\circ}C$ and significant increase of proliferation and viability in sub-passaged TSCs was detected in the $35^{\circ}C$ culture condition. Moreover, sub-passage of primary TSCs at $35^{\circ}C$ induced no significant effects on proliferation and viability. In contrast, in case of DBA/2 strain, significantly improved proliferation were detected in the primary TSCs cultured at $35^{\circ}C$, which showed no significant difference in the viability, compared to those at $37^{\circ}C$. Furthermore, sub-passaged TSCs cultured at $37^{\circ}C$ showed no significant differences in proliferation and viability, compared to those at $35^{\circ}C$. However, with significant decrease of proliferation induced by sub-passage of primary TSCs at $35^{\circ}C$, no significant effects on proliferation and viability were resulted from sub-passage of primary TSCs at $37^{\circ}C$. From these results, culture temperature of primary TSCs derived from outbred and inbred strain of mouse could be separately optimized in primary culture and subculture.

Soluble Production of CMP-Neu5Ac Synthetase by Co-expression of Chaperone Proteins in Escherichia coli (샤페론 단백질 동시 발현기술을 이용한 수용성 CMP-Neu5Ac Synthetase 생산)

  • Choi, Hwa Young;Li, Ling;Cho, Seung Kee;Lee, Won-Heong;Seo, Jin-Ho;Han, Nam Soo
    • Microbiology and Biotechnology Letters
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    • v.42 no.2
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    • pp.190-193
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    • 2014
  • CMP-Neu5Ac synthetase is a key enzyme for the synthesis of CMP-Neu5Ac, which is an essential precursor of sialylated glycoconjugates. For the soluble expression of the CMP-Neu5Ac synthetase gene (neuA) from Escherichia coli K1, various heat shock proteins were co-expressed in E. coli BL21 (DE3) Star. In order to do this, a pG-KJE8 plasmid, encoding genes for GroEL-ES and DnaK-DnaJ-GrpE, was co-transformed with neuA and was expressed at $20^{\circ}C$ by the addition of 0.01 mM IPTG and 0.005 mg/ml L-arabinose. The co-expression of a variety of heat shock proteins resulted in the remarkably improved production of soluble CMP-Neu5Ac synthetase in E. coli.

Analysis of residual stress of Nitinol by surface Polishing Method (표면 연마 방법에 따른 니티놀 잔류응력 분석)

  • Jeong, Ji-Seon;Hong, Kwang-Pyo;Kim, Woon-yong;Cho, Myeong-Woo
    • Design & Manufacturing
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    • v.11 no.2
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    • pp.51-56
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    • 2017
  • Nitinol, a shape memory alloy (SMA), is manufactured from titanium and nickel and it used in various fields such as electrical applications, micro sensors. It is also recommended as a material in medical for implant because it has excellent organic compatibility. Nitinol is intended to be inserted into the human body, products require a high-quality surface and low residual stress. To overcome this problems, explore electrolyte polishing (EP) is being explored that may be appropriate for use with nitinol. EP is a particularly useful machining method because, as a non contact machining method, it produces neither machining heat nor internal stress in the machined materials. Sandpaper polishing is also useful machining method because, as a contact machining method, it can easily good surface roughness in the machined materials. The electrolyte polishing (EP) process has an effect of improving the surface roughness as well as the film polishing process, but has a characteristic that the residual stress is hardly generated because the work hardened layer is not formed on the processed surface. The sandpaper polishing process has the effect of improving the surface roughness but the residual stress remains in the surface. We experimented with three conditions of polishing process. First condition is the conventional polishing. Second condition is the electrochemical polishing(EP). And Last condition is a mixing process with the conventional polishing and the EP. Surface roughness and residual stress of the nitinol before a polishing process were $0.474{\mu}mRa$, -45.38MPa. Surface roughness and residual stress of the nitinol after mixing process of the conventional polishing and the EP were $1.071{\mu}mRa$, -143.157MPa. Surface roughness and residual stress of the nitinol after conventional polishing were $0.385{\mu}mRa$ and -205.15MPa. Surface roughness and residual stress of sandpaper and EP nitinol were $1.071{\mu}mRa$, -143.157MPa. The result shows that the EP process is a residual stress free process that eliminates the residual stress on the surface while eliminating the deformed layer remaining on the surface through composite surface machining rather than single surface machining. The EP process can be used for biomaterials such as nitinol and be applied to polishing of wafers and various fields.

Histological evaluation of direct pulp capping with DSP-derived synthetic peptide in beagle dog (비글견에서 DSP 유도 합성 펩타이드를 이용한 직접 치수 복조술에 대한 조직학적 연구)

  • Kim, Jae-Hoon;Hong, Jun-Bae;Lim, Bum-Soon;Cho, Byeong-Hoon
    • Restorative Dentistry and Endodontics
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    • v.34 no.2
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    • pp.120-129
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    • 2009
  • The purpose of this study was to investigate the pulpal response to direct pulp capping with dentin sialoprotein (DSP) -derived synthetic peptide in teeth of dogs, and to compare its efficacy to capping substances $Ca(OH)_2$ and white mineral trioxide aggregate (WMTA). A total of 72 teeth of 6 healthy male beagle dogs were used. The mechanically exposed pulps were capped with one of the following: (1) DSP-derived synthetic peptide (PEP group): (2) $Ca(OH)_2$ (CH group): (3) a mixture paste of peptide and $Ca(OH)_2$ (PEP+CH group): or (4) white MTA (WMTA group). The access cavity was restored with a reinforced glass ionomer cement. Two dogs were sacrificed at each pre-determined intervals (2 weeks, 1 month, and 3 months). After the specimens were prepared for standard histological processing, sections were stained with hematoxylin and eosin. Under a light microscope, inflammatory response and hard tissue formation were evaluated in a blind manner by 2 observers. In the PEP group, only 3 of 17 specimens showed hard tissue formation, indication that the DSP-derived synthetic peptide did not induce proper healing of the pulp. Compared with the CH group, the PEP group demonstrated an increased inflammatory response and poor hard tissue formation. The CH and WMTA groups showed similar results for direct pulp capping in mechanically exposed teeth of dogs.

Synthesis of Thermosensitive and Biodegradable Methoxy Poly(ethylene glycol)-Polycaprolactone and Methoxy Poly(ethylene glycol)-Poly(lactic acid) Block Copolymers (온도감응 및 생분해성 폴리에틸렌 글리콜-폴리카프로락톤과 폴리에틸렌 글리콜-폴리락타이드 공중합체의 합성)

  • 서광수;박종수;김문석;조선행;이해방;강길선
    • Polymer(Korea)
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    • v.28 no.3
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    • pp.211-217
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    • 2004
  • The sol to gel transition of aqueous solution of block copolymers consisting of methoxy poly (ethylene glycol) (MPEG) and biodegradable polyesters such as $\varepsilon$-caprolactone and L-lactide was investigated as a function of temperature. MPEG-PCL was prepared by ring opening polymerization of $\varepsilon$-caprolactone in the presence of HClㆍEt$_2$O as monomer activator at room temperature. Also, MPEG-PLLA was prepared by ring opening polymerization of L-lactide in the presence of stannous octoate at 115$^{\circ}C$. The properties of block copolymers were investigated by $^1$H-NMR, IR, and GPC as well as the observation of thermo sensitive phase transition in aqueous solution. As the hydrophobic block length increased, the sol to gel transition temperature increased and curve of that steepen to lower concentration. To confirm the gel formation at body temperature, we observed the formation of gel in the mice body after injection of 20 wt% aqueous solution of each block copolymer. After surging, we investigated the gelation in mice. The results obtained in this study confirmed the feasibility as biomaterials of injectable implantation for controlled release of drug and protein delivery.

Mechanical Property and Cell Compatibility of Silk/PLGA Hybrid Scaffold; In Vitro Study (실크/PLGA 하이브리드 지지체의 기계적 물성과 세포친화력; in vitro 연구)

  • Song, Yi-Seul;Yoo, Han-Na;Eum, Shin;Kim, On-You;Yoo, Suk-Chul;Kim, Hyung-Eun;Lee, Dong-Won;Khang, Gil-Son
    • Polymer(Korea)
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    • v.35 no.3
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    • pp.189-195
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    • 2011
  • The design of new bioactive scaffolds offering physiologic environment for tissue formation is an important frontier in biomaterials research. In this study, we performed compressive strength, water-uptake ability, and SEM analysis for physical property assessment of 3-D silk/PLGA scaffold, and investigated the adhesion, proliferation, phenotype maintenance, and inflammatory responses of RAW 264.7 and NIH/3T3 for cell compatibility. Scaffolds were prepared by the solvent casting/salt leaching method and their compressive strength and water-uptake ability were excellent at 20 wt% silk content. Result of cell compatibility assay showed that inflammatory responses distinctly decreased, and initial adhesion and proliferation were maximized at 20 wt% silk content. In conclusion, we suggest that silk/PLGA scaffolds may be useful to tissue engineering applications.