• Title/Summary/Keyword: pH-Responsive

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Surgical Oocyte Retrieval and the Developmental Potential of the Oocytes Derived from Prepubertal Calves

  • Yeh, S.P.;Ju, J.C.;Tseng, J.K.;Chou, P.C.;Chen, C.H.;Chih, T.;Fan, Y.K.
    • Asian-Australasian Journal of Animal Sciences
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    • v.17 no.2
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    • pp.174-178
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    • 2004
  • The objectives of this study were to investigate the ovarian responsiveness of juvenile calves to exogenous gonadotropin treatments and to establish the oocyte retrieval technique for prepubertal heifers. Three 78-day-old calves were treated with 4 doses (40, 30, 30 and 30 mg) of FSH (Folltropin V) at 12 h interval up to 229 day-old. Surgical oocyte retrieval was performed 24 h after the last injection of FSH. Calves with good ovarian responses to FSH treatment had an average ovarian size of $5{\times}3$ cm compared to $3{\times}2$ cm in the less-responsive animals. Large variations were observed in the number of total follicles ($51{\pm}45$), aspirated follicles ($39{\pm}36$), oocytes recovered ($23{\pm}25$) and usable oocytes recovered ($11{\pm}19$) during 78 to 229 day-old. Oocytes derived from prepubertal calves had significantly lower maturation rate than those from cows (34 vs. 100%, p<0.05). Mean diameters of calf oocytes ($144{\pm}1{\mu}m$) and ooplasm ($110{\pm}1 {\mu}m$) were significantly lower than those of cows ($149{\pm}1$ and $25{\pm}1{\mu}m$, respectively). The diameter of the ooplasm also increased significantly after in vitro maturation (IVM) ($108{\pm}1$ vs. $112{\pm}1{\mu}m$). However, further studies are required to optimize the IVP system for the oocytes derived from prepubertal heifers.

Antibiofilm activity of polyethylene glycol-quercetin nanoparticles-loaded gelatin-N,O-carboxymethyl chitosan composite nanogels against Staphylococcus epidermidis

  • Wanhe Luo;Yongtao Jiang;Jinhuan Liu;Beibei Sun;Xiuge Gao;Samah Attia Algharib;Dawei Guo;Jie Wei;Yurong Wei
    • Journal of Veterinary Science
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    • v.25 no.2
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    • pp.30.1-30.16
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    • 2024
  • Background: Biofilms, such as those from Staphylococcus epidermidis, are generally insensitive to traditional antimicrobial agents, making it difficult to inhibit their formation. Although quercetin has excellent antibiofilm effects, its clinical applications are limited by the lack of sustained and targeted release at the site of S. epidermidis infection. Objectives: Polyethylene glycol-quercetin nanoparticles (PQ-NPs)-loaded gelatin-N,O-carboxymethyl chitosan (N,O-CMCS) composite nanogels were prepared and assessed for the on-demand release potential for reducing S. epidermidis biofilm formation. Methods: The formation mechanism, physicochemical characterization, and antibiofilm activity of PQ-nanogels against S. epidermidis were studied. Results: Physicochemical characterization confirmed that PQ-nanogels had been prepared by the electrostatic interactions between gelatin and N,O-CMCS with sodium tripolyphosphate. The PQ-nanogels exhibited obvious pH and gelatinase-responsive to achieve on-demand release in the micro-environment (pH 5.5 and gelatinase) of S. epidermidis. In addition, PQ-nanogels had excellent antibiofilm activity, and the potential antibiofilm mechanism may enhance its antibiofilm activity by reducing its relative biofilm formation, surface hydrophobicity, exopolysaccharides production, and eDNA production. Conclusions: This study will guide the development of the dual responsiveness (pH and gelatinase) of nanogels to achieve on-demand release for reducing S. epidermidis biofilm formation.

Perchlorate Ion-Selective PVC Membrane Electrode Based on the Quaternary Ammonium Salts (제4급 암모늄염을 이용한 과염소산 이온선택성 PVC막 전극)

  • 안형환;김용렬;강현춘;이한섭;이병철;강안수
    • Membrane Journal
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    • v.3 no.3
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    • pp.126-135
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    • 1993
  • Perchlorate ion-selective PVC membrane electrode responsive to $10^{-6}M$ was developed by incorporating the ion-pair complex of perchlorate with the quaternary ammonium salts as a active material. The effect of chemical structure, the content of active material, the kinds of plasticizers, and the membrane thickness on the electrode characteristics such as the linear response range and Nernstian slope of the electrode were studied. With the results, the useful pH range and the selectivity coefficients to various interfering anions were compared and investigated. It was obtained that the effect of the chemical structure of an active material on the electrode characteristics was improved with increasing the alkyl chain length of the quarternary ammonium salts in the ascending order of Aliquat 336P, TOAP, TDAP, and TDDAP. The electrode characteristics was improved with the decrease of the active material content below the optimum membrane composition, and DBP was the best as a plasticizer. The optimum membrane composition was 9.09wt% of TDDAP, 30.3wt% of PVC, and 60.6wt% of ptasticizer(DBP). And the optimum membrane thickness was0.45mm at this composition. Under the above condition, thelinear response ranger was $10^{-1}~1.2 {\times} 10^{-6}M$, and the detection limit was $5.1{\times}10^{-7}M$ with the Nernstian slope of 57mV/decade of activity of perchlorate ion. The electrode potential was stable within the pH range from 4 to 11. The selectivity coefficient was as shown below : $SCN^->I^->NO_3^->Br^->ClO_3^->F^->Cl^->SO_4^{2-}$

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Flow Characteristics of Elastin-Like Polypeptide(ELP) Coated Packed Bed (온도 감응성 폴리펩티드로 표면 처리된 충전층의 유동 특성)

  • Kim, Duck-Jong;Lee, Jong-Hwan;Park, Sang-Jin;Hyun, Jin-Ho
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.3187-3190
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    • 2007
  • Elastin-Like polypeptide (ELP) composed of elastin-based repeating units is an artificial biomaterial which is biocompatible and non-immunogenic. ELP shows a characteristic inverse phase transition between hydrophobic and hydrophilic phase by external stimuli such as salt, pH and temperature. In this study, ELP coated PS (polystyrene) beads are packed in tubing and the thermo -responsive flow characteristics of the packed bed are investigated. Preliminary test results show that the control of the fluid flow can be achieved by using the temperature driven phase transition effect of the ELP coated beads in a microchannel.

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Temporal and Spatial Change of Sediment Toxicity in Keumho River and its Major Influents, Taegu, Korea (대구지역 금호강 및 주요 지천 퇴적물의 시 . 공간적 독성변화)

  • 정홍배;문성환;정진애;김재현;박정규;배철한;황인영
    • Environmental Analysis Health and Toxicology
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    • v.16 no.4
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    • pp.161-170
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    • 2001
  • In aqueous ecosystems, the level of toxicity is highly responsive dependant to multiple variables, including rainfall, sunlight, pH, adhesion, etc. Because Korea has particularly distinct wet and dry seasons, the toxicity of pollutants in rivers or streams is dependant on the sampling season and time. In order to examine the effects of rainfall on toxicity, sediment samples were collected from five sites along the Keumho river. It was found that Microtox toxicity levels were generally higher during the dry season than the wet season. It indicated that river pollutants are carried off more quickly by the water during the wet season. As a result, it was recommended that the point sources of pollutants of the Keumho river would be placed between KH3 (Paldalgyo) and KH4(Keumhogyo), KH4(Keumhogyo) and KH5(Dasa).

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Temperature-responsive bioactive hydrogels based on a multifunctional recombinant elastin-like polymer

  • Santo, Vitor E.;Prieto, Susana;Testera, Ana M.;Arias, Francisco J.;Alonso, Matilde;Mano, Joao F.;Rodriguez-Cabello, Jose Carlos
    • Biomaterials and Biomechanics in Bioengineering
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    • v.2 no.1
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    • pp.47-59
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    • 2015
  • A bioactive and multifunctional elastin-like polymer (ELP) was produced by genetic engineering techniques to develop new artificial matrices with the ability to mimic the extracellular matrix (ECM). The basic composition of this ELP is a thermo- and pH-sensitive elastin pentapeptide which has been enriched with RGD-containing domains, the RGD loop of fibronectin, for recognition by integrin receptors on their sequence to promote efficient cell attachment. Hydrogels of this RGD-containing polymer were obtained by crosslinking with hexamethylene diisocyanate, a lysine-targeted crosslinker. These materials retain the "smart" nature and temperature-responsive character, and the desired mechanical behavior of the elastin-like polymer family. The influence of the degree of crosslinking on the morphology and properties of the matrices were tested by calorimetric techniques and scanning electron microscopy (SEM). Their mechanical behavior was studied by dynamical mechanical analysis (DMA). These results show the potential of these materials in biomedical applications, especially in the development of smart systems for tissue engineering.

Sodium Salicylate Activates p38MAPK Though a Specific-Sensing Mechanism, Distinct from Pathways Used by Oxidative Stress, Heat Shock, and Hyperosmotic Stress

  • Kim, Jung-Mo;Oh, Su-Young;Kim, Min-Young;Seo, Myoung-Suk;Kang, Chi-Duk;Park, Hye-Gyeong;Kang, Ho-Sung
    • Biomedical Science Letters
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    • v.9 no.4
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    • pp.241-248
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    • 2003
  • Sodium salicylate, a plant stress hormone that plays an important role(s) in defenses against pathogenic microbial and herbivore attack, has been shown to induce a variety of cell responses such as anti-inflammation, cell cycle arrest and apoptosis in animal cells. p38MAPK plays a critical role(s) in the cell regulation by sodium salicylate. However, the signal pathway for sodium salicylate-induced p38MAPK activation is yet unclear. In this study, we show that although sodium salicylate enhances reactive oxygen species (ROS) production, N-acetyl-L-cysteine, a general ROS scavenger, did not prevent sodium salicylate-induced p38MAPK, indicating ROS-independent activation of p38MAPK by sodium salicylate. Sodium salicylate-activated p38MAPK appeared to be very rapidly down-regulated 2 min after removal of sodium salicylate. Interestingly, sodium salicylate-pretreated cells remained fully responsive to re-induction of p38MAPK activity by a second sodium salicylate stimulation or by other stresses, $H_2O$$_2$ and methyl jasmonate (MeJA), thereby indicating that sodium salicylate does not exhibit both homologous and heterologous desensitization. In contrast, pre-exposure to MeJA, $H_2O$$_2$, heat shock, or hyperosmotic stress reduced the responsiveness to subsequent homologous stimulation. Sodium salicylate was able to activate p38MAPK in cells desensitized by other heterologous p38MAPK activators. These results indicate that there is a sensing mechanism highly specific to sodium salicylate for activation of p38MAPK, distinct trom pathways used by other stressors such as MeJA, $H_2O$$_2$ heat shock, and hyperosmotic stress.

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Effects of Lactobacillus helveticus Fermentation on the Ca2+ Release and Antioxidative Properties of Sheep Bone Hydrolysate

  • Han, Keguang;Cao, Jing;Wang, Jinghui;Chen, Jing;Yuan, Kai;Pang, Fengping;Gu, Shaopeng;Huo, Nairui
    • Food Science of Animal Resources
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    • v.38 no.6
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    • pp.1144-1154
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    • 2018
  • Both the calcium and collagen in bone powder are hard to be absorbed by the body. Although enzymatic hydrolysis by protease increased the bio-availability of bone powder, it was a meaningful try to further increase $Ca^{2+}$ release, oligopeptide formation and antioxidant activity of the sheep bone hydrolysate (SBH) by lactic acid bacteria (LAB) fermentation. Lactobacillus helveticus was selected as the starter for its highest protease-producing ability among 5 tested LAB strains. The content of liberated $Ca^{2+}$ was measured as the responsive value in the response surface methodology (RSM) for optimizing the fermenting parameters. When SBH (adjusted to pH 6.1) supplemented with 1.0% glucose was inoculated 3.0% L. helveticus and incubated for 29.4 h at $36^{\circ}C$, $Ca^{2+}$ content in the fermented SBH significantly increased (p<0.01), and so did the degree of hydrolysis and the obtaining rate of oligopeptide. The viable counts of L. helveticus reached to $1.1{\times}10^{10}CFU/mL$. Results of Pearson correlation analysis demonstrated that LAB viable counts, $Ca^{2+}$ levels, obtaining rates of oligopeptide and the yield of polypeptide were positively correlated with each other (p<0.01). The abilities of SBH to scavenge the free radicals of DPPH, OH and ABTS were also markedly enhanced after fermentation. In conclusion, L. helveticus fermentation can further boost the release of free $Ca^{2+}$ and oligopeptide, enhance the antioxidant ability of SBH. The L. helveticus fermented SBH can be developed as a novel functional dietary supplement product.

Preparation and Characterizations of Complex Composed of ${\beta}$-Cyclodextrin Polymer/Cinnamic Acid (베타-사이클로 덱스트린 중합체/신남산 복합체의 제조 및 특성 연구)

  • Mok, Eun Young;Cha, Hyun Ju;Kim, Jin-Chul
    • Applied Chemistry for Engineering
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    • v.23 no.5
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    • pp.462-466
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    • 2012
  • $\beta$-cyclodextrin ($\beta$-CD) polymers were prepared in a strong alkali condition solution (NaOH solution 30% (w/v)) using epichlorohydrin (EPI) as a cross-linker, and the molar ratio of EPI to $\beta$-CD was 10 : 1. The $\beta$-CD content in $\beta$-CD polymers is about 52%. In order to get the photo-responsible and pH-responsible, cinnamic acid was added to be inserted into the cavities of $\beta$-CD due to the hydrophobic interaction. The complex formation was confirmed using transmission electron microscope. The dimerization degree of complexes increased under UV irradiation at $\lambda$ = 365 nm but decreased under the UV irradiation at $\lambda$ = 254 nm. Dynamic light scattering analysis of particle sizes showed that the sizes of complexes did not change with different UV wavelength. Moreover, the complexes were pH-responsible because of the carboxyl group of cinnamic acid, but the size and zeta potential of the complex did not change in strong acid and alkali conditions.

Blossom smart expander technology for tissue expander-based breast reconstruction facilitates shorter duration to full expansion: A pilot study

  • Choi, Youna K.;Rochlin, Danielle H.;Nguyen, Dung H.
    • Archives of Plastic Surgery
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    • v.47 no.5
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    • pp.419-427
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    • 2020
  • Background This study evaluated the Blossom system, an innovative self-filling, rate-controlled, pressure-responsive saline tissue expander (TE) system. We investigated the feasibility of utilizing this technology to facilitate implant-based and combined flap with implant-based breast reconstruction in comparison to conventional tissue expansion. Methods In this prospective, single-center, single-surgeon pilot study, participants underwent either implant-based breast reconstruction or a combination of autologous flap and implantbased breast reconstruction. Outcome measures included time to full expansion, complications, total expansion volume, and pain scores. Results Fourteen patients (TEs; n=22), were included in this study. The mean time to full expansion was 13.4 days (standard error of the mean [SEM], 1.3 days) in the combination group and 11.7 days (SEM, 1.4 days) in the implant group (P=0.78). The overall major complication rate was 4.5% (n=1). No statistically significant differences were found in the complication rate between the combination group and the implant group. The maximum patient-reported pain scores during the expansion process were low, but were significantly higher in the combination group (mean, 2.00±0.09) than in the implant group (mean, 0.29±0.25; P=0.005). Conclusions The reported average duration for conventional subcutaneous TE expansion is 79.4 days, but this pilot study using the Blossom system achieved an average expansion duration of less than 14 days in both groups. The Blossom system may accommodate single-stage breast reconstruction. The overall complication rate of this study was 4.5%, which is promising compared to the reported complication rates of two-stage breast reconstruction with TEs (20%-45%).