• Title/Summary/Keyword: pivalate

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Preparation of Syndiotacticity-Rich Ultrahigh Molecular Weight Poly(vinyl alcohol) with High Yield Using Low Temperature Suspension Polymerization of Vinyl Pivalate (피발산비닐의 저온 현탁중합에 의한 고교대배열 초고분자량 폴리비닐알코올의 고효율 제조)

  • 류원석;박찬식
    • Proceedings of the Korean Fiber Society Conference
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    • 2002.04a
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    • pp.33-36
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    • 2002
  • 폴리비닐알코올 (poly(vinyl alcohol), PVA)은 의류 및 산업용 섬유, 막, 약물전달, 암세포 괴사용 색전제등에 널리 사용되고 있다[1,2]. 이런 PVA와 같은 비닐계 고분자는 분자량 이외에도 입체규칙성에 따라 그 물리적 성질이 변화하는데 그 입체규칙성에 따라 혼성배열, 동일배열 및 교대배열 고분자로 분류할 수 있다. PVA는 일반적으로 55% 이상의 교대배열 다이애드기 함량을 가질 때 교대배열 PVA라고 불린다. (중략)

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Critical Syndiotacticity Required for In-Situ Fibrillation of Poly(vinyl Alcohol) during Saponification of Poly(vinyl Ester)

  • Lyoo, Won-Seok;John Blackwell
    • Proceedings of the Korean Fiber Society Conference
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    • 1998.04a
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    • pp.130-134
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    • 1998
  • The physical properties of poly(vinyl alcohol) (PVA) are highly dependent on the degree of syndiotacticity, which is determined primarily by the choice of the vinyl ester monomer precursor. Efforts to produce more syndiotactic PVAs, as well to increase the molecular weight, have centered on the polymerization of vinyl trifluoroacetate,$^1$ vinyl trichloroacetate,$^2$ and vinyl pivalate (VPi).(omitted)

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Dyeing of Microfibrillar Poly(vinyl Alcohol) Fiber - Evaluation of Surface Area of Microfibrillar Fiber- (폴리비닐알코올 마이크로피브릴 섬유의 염색 -마이크로피브릴 섬유의 표면적 평가-)

  • 김한도;김재필;김삼수;류원석
    • Proceedings of the Korean Fiber Society Conference
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    • 2001.10a
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    • pp.368-370
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    • 2001
  • 폴리비닐알코올(poly(vinyl alcohol) (PVA))은 구조적인 단량체인 비닐알코올의 호변 이성질화 때문에 직접 중합에 의해서는 얻을 수 없으며, 아세트산 비닐 (vinyl acetate (VAc))이나 피발산 비닐 (vinyl pivalate (VPi))같은 비닐에스테르 계열 단량체를 사용하여 중합과 비누화 반응을 거쳐 제조되고 비누화 반응에서 모든 측쇄기가 효과적으로 제거되는 히드록시기 함유 선형 결정성 고분자이다[1-4]. (중략)

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A Case of Treating with Desoxycorticosterone Pivalate(DOCP) against Canine Hypoadrenocorticism uncontrolled with Fludrocortisone (Fludrocortisone으로 조절되지 않는 부신피질기능저하증 개를 DOCP로 치료한 1례)

  • Sohn, Suh-Young;Seo, Kyoung-Won;Kim, Sae-Um;Hwang, Cheol-Yong;Youn, Hwa-Young
    • Journal of Veterinary Clinics
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    • v.26 no.5
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    • pp.472-475
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    • 2009
  • A 3-year old, female Cocker Spaniel dog was referred to Seoul National University Hospital for Animals with depression and vomiting. The dog was diagnosed as hypoadrenocorticism based on the typical electrolyte alteration and the result of adrenocorticotropic hormone (ACTH) stimulation test. Initial treatment with oral fludrocortisone at a dose rate of 0.02 mg/kg/q24h for 6 weeks period was ineffective at maintaining serum electrolyte concentrations within normal limits. Although a dose rate of oral fludrocortisone was significantly increased up to 0.06 mg/kg/q24h during 24 weeks period, the treatment was still ineffective. Moreover, the patient showed side effects related to the glucocorticoid excess including PU/PD, weight gain and lipemia. After alternation with desoxycorticosterone pivalate (DOCP, 2.2 mg/kg, IM) every 25 day, the clinical signs was disappeared and the electrolyte balance was maintain with no side effect. Therefore, DOCP may be suggested as an effective drug in canine hypoadrenocorticism uncontrolled with oral fludrocortisone.

Preparation of Syndiotactic Poly(vinyl alcohol) Microfibrils with Radiopaque Inorganic Particles (방사선불투과성 무기입자를 첨가한 교대배열 폴리비닐알코올 마이크로피브릴의 제조)

  • Jo, Hye Won;Cha, Jin Wook;Han, Sung Soo;Lee, Joon Seok;Oh, Tae Hwan
    • Polymer(Korea)
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    • v.37 no.5
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    • pp.563-570
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    • 2013
  • Poly(vinyl pivalate) (PVPi) was bulk polymerized to make poly(vinyl alcohol) (PVA) microfibrils to apply for polymeric embolization coils replacing metalic coils. Then, syndiotactic PVA (s-PVA) microfibrils having number-average degree of polymerization of 1100 and s-diad content of 60.4% were prepared via saponification of the PVPi with no separate spinning process. To make s-PVA microfibrils with radiopacity, zirconium dioxide ($ZrO_2$) and barium sulfate ($BaSO_4$) were added into s-PVA microfibrils during saponification. The computed tomography (CT) value indicating radiopacity reached up to over 1000 when the amount of $ZrO_2$ and $BaSO_4$ were 12 and 6 wt%, respectively.

Hypoadrenocorticism in a 1-Year-Old Korean Shorthair Cat

  • Jung, Hansol;Jeong, Yunho;Kim, Yoonhwan;Choi, Sooyoung;Park, Inchul;Ahn, Jin-Ok
    • Journal of Veterinary Clinics
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    • v.39 no.3
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    • pp.144-148
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    • 2022
  • A one-year-old spayed female Korean Shorthair cat presented to Kangwon National University Veterinary Hospital with vomiting, weight loss, lethargy, loss of appetite, and polyuria that lasted for more than two weeks. The body condition score, blood pressure, heart rate, and body temperature were abnormally low, and the physical examination findings were consistent with moderate dehydration. Hematological and biochemical tests demonstrated mild azotemia and a low Na:K ratio. Additional abdominal ultrasound imaging revealed reduced size of both adrenal glands. The adrenocorticotropic hormone (ACTH) stimulation test showed decreased post-ACTH cortisol and aldosterone levels and increased endogenous ACTH levels, confirming a diagnosis of primary hypoadrenocorticism. The cat was treated with subcutaneous injections of desoxycorticosterone pivalate (DOCP) and oral prednisolone supplementation, and subsequent electrolyte analysis showed a normal Na:K ratio. Clinical symptoms were also improved in response to treatment. Hypoadrenocorticism in cats is a very rare disease, but it should not be excluded as a potential diagnosis in favor of kidney diseases or other conditions, especially when the Na:K ratio is low. In addition, the prognosis for the disease and the response to DOCP treatment should be further evaluated in cats.

Preparation of High Molecular Weight Atactic Poly(vinyl alcohol)/Dye Complex Film (고분자량 혼성배열 폴리비닐알코올/염료 복합체 필름의 제조)

  • Park, Joo-Min;Kim, Sam-Soo;Lyoo, Won-Seok
    • Proceedings of the Korean Fiber Society Conference
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    • 2003.04a
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    • pp.48-51
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    • 2003
  • Poly(vinyl alcohol) (PVA) obtained by the saponification of poly(vinyl ester) like poly(vinyl acetate) or poly(vinyl pivalate) is a linen. semicrystalline polymer, which have been widely used as fibers for clothes and industries, films, membranes, medicines for drug delivery system, and cancer cell-killing embolic materials[1-3]. PVA fibers and films have high tensile and compressive strengths, high tensile modulus, and good abrasion resistance due to its highest crystalline lattice modulus. (omitted)

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Preparation of Water-Soluble Syndiotacticity-Rich Low Molecular Weight Poly(vinyl alcohol) by Solution Copolymerization of Vinyl Pivalate/Vinyl Acetate in Tetrahydrofuran and Saponification (피발산비닐과 아세트산비닐의 테트라히드로푸란계 용액공중합에 의한 수용성 저분자량 교대배열 폴리비닐알코올의 제조)

  • Lyo, Won-Seok;Yeum, Jeong-Hyun;Ji, Byung-Chul
    • Proceedings of the Korean Fiber Society Conference
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    • 2002.04a
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    • pp.187-190
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    • 2002
  • Poly(vinyl alcohol) (PVA) is a representative hydrophilic and water-soluble polymer and widely employed in various applications such as fibers for clothes and industries, films, membranes, medicines for drug delivery system, and cancer cell-killing embolic materials. Moreover, PVA fibers, gels, and films are potentially high-performance materials because they have high tensile and impact strengths, high tensile modulus, high abrasion resistance, excellent alkali resistance, and oxygen barrier property which are superior to those of any known polymers[1,2]. (omitted)

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