• Journal of Embryo Transfer
• /
• v.13 no.2
• /
• pp.127-137
• /
• 1998

This experiment was carried out to investigate the factors affecting superovulation in rabbits and to determine the effect of pFSH and PMSG on ovarian superovulatory responses and embryo production, and the effect of superovulation treatment with a single injection of pFSH dissolved in polyvinylpyrrolidone on the ovarian responses and the embryo quality. The results obtained were suonmerized as follows: Superovulatory response resulted in significantly (P<0.05) higher ovulation rates and more embryos in spring or autumn, compared with summer or winter. Repeated superovulatory treatments with PMSG leaded to a significantly(P<0.05) decreased number of total follicles and recovered ova. Superovulation with pFSH resulted in the higher number of ovulated follicles and recovered ova than with PMSG. A single subcutaneous injection of pFSH dissolved in 25% PVP resulted in the more ovulation points(33.2) and recovered embryos(30.2), which were comparable to the multiple injections of pFSH(44.8 vs 37.7).These results indicated that the treatment with a single injection of FSH dissolved in PVP was an efficient and simple alternative method to the conventional multiple FSH injections for superovulation in rabbits.

• Membrane and Water Treatment
• /
• v.7 no.4
• /
• pp.355-365
• /
• 2016

The improvement of fouling resistance of porous polymeric membrane is one of the most important targets in membrane preparation for water purification in many process like wastewater treatment. Membranes can be modified by various techniques, including the treatment of polymer material, blending of hydrophilic polymer into polymer solution, and post treatment of fabricated membrane. This research proposed the modifications of morphology and surface property of hydrophobic membrane by blending polyethersulfone (PES) with three polymeric additives, polyvinylpyrrolidone (PVP), Pluronic F127 (Plu), and Tetronic 1307 (Tet). PES hollow fiber membranes were fabricated via dry-wet spinning process by using a spinneret with inner and outer diameter of 0.7 and 1.0 mm, respectively. The morphology changes of PES blend membrane by those additives, as well as the change of performance in ultrafiltration module were comparatively observed. The surface structure of membranes was characterized by atomic force microscopy and Fourier transform infra red spectroscopy. The cross section morphology of PES blend hollow fiber membranes was investigated by scanning electron microscopy. The results showed that all polymeric additives blended in this system affected to improve the performances of PES membrane. The ultra-filtration experiment confirmed that PES-PVP membrane showed the best performance among the three membranes on the basis of filtration stability.

• Membrane and Water Treatment
• /
• v.11 no.2
• /
• pp.159-166
• /
• 2020

In this study, the performance and antifouling properties of polysulfone (PSf) and polyvinylidene fluoride/polyvinylpyrrolidone (PVDF/PVP) membranes in a membrane bioreactor (MBR) were investigated. The membranes were prepared via phase inversion method, and then characterized by a set of analyses including contact angle, porosity and water flux and applied in a lab-scale MBR system. Soluble microbial product (SMP), extracellular polymeric substance (EPS), FTIR, gel permission chromatography (GPC) and particle size distribution (PSD) analyses were also carried out for MBR system. The results showed that the MBR with PSf membrane had higher hydrophobic organic compounds which resulted in formation of larger flocs in MBR. However, in this MBR had high compressibility coefficient of cake layer was higher (n=0.91) compared to MBR with PVDF/PVP membrane (n=0.8); hence, the fouling was more profound. GPC analysis revealed that compounds with molecular weight lower than 2 kDa are more formed on PSf membrane more than PVDF/PVP membrane. The results of FTIR analysis confirmed the presence of polysaccharide and protein compounds on the cake layer of both membranes which was in good agreement with EPS analysis. In addition, the results showed that their concentration was higher for the cake on PSf membrane.

• Journal of Pharmaceutical Investigation
• /
• v.32 no.3
• /
• pp.173-179
• /
• 2002

Solid dispersions of ipriflavone with PVP were prepared by a spray-drying method in order to improve the bioavailability. They were measured with scanning electron microscopy, differential scanning calorimetry, x-ray powder diffraction, and Fourier transform infrared spectroscopy to evaluate the physicochemical interaction between ipriflavone and PVP and study the correlation between these physicochemical characteristics and bioavailability. Ipriflavone exhibited crystallinity, whereas PVP was almost amorphous. The area of the endotherm $({\Delta}H)$ of freezer milled ipriflavone, freezer milled ipriflavone physically mixed with freezer milled PVP, and physically mixed ipriflavone with PVP was almost the same, whereas ${\Delta}H$ of the solid dispersed ipriflavone with PVP was much smaller than that of the other preparation types. Also, the crystallinity and the crystal size of ipriflavone in the solid dispersed ipriflavone with PVP were much smaller than those of the other preparation types. From the in vivo test, the AUC of the solid dispersed ipriflavone with PVP was approximately 10 times higher than that of the physically mixed ipriflavone with PVP. The solid dispersion using the spray-drying method with a water-soluble polymer, PVP, may be effective for the improvement of the bioavailability.

• Korean Journal of Materials Research
• /
• v.26 no.9
• /
• pp.472-477
• /
• 2016

Microstructure evolutions of thermosetting resin coating layers fabricated by electrostatic spray deposition (ESD) at various processing conditions were investigated. Two different typical polymer systems, a thermosetting phenol-formaldehyde resin and a thermoplastic polyvinylpyrrolidone (PVP), were employed for a comparative study. Precursor solutions of the phenol-formaldehyde resin and of the PVP were electro-sprayed on heated silicon substrates. Fundamental differences in the thermomechanical properties of the polymers resulted in distinct ways of microstructure evolution of the electro-sprayed polymer films. For the thermosetting polymer, phenol-formaldehyde resin, vertically aligned micro-rod structures developed when it was deposited by ESD under controlled processing conditions. Through extensive microstructure and thermal analyses, it was found that the vertically aligned micro-rod structures of phenol-formaldehyde resin were formed as a result of the rheological behavior of the thermosetting phenol-formaldehyde resin and the preferential landing phenomenon of the ESD method.

• Bulletin of the Korean Chemical Society
• /
• v.32 no.9
• /
• pp.3338-3342
• /
• 2011

We fabricated ceria ($CeO_2$) nanofibers by applying a mixed solution of polyvinylpyrrolidone (PVP) and various concentrations of cerium nitrate hydrate ($Ce(NO_3)_3$) ranging from 15.0 to 26.0 wt % by the electrospinning process. Ceria nanofibers were obtained after calcining PVP/$Ce(NO_3)_3$ nanofiber composites at 873 and 1173 K. The SEM images indicated that the diameters of $CeO_2$ nanofibers calcined at 873 and 1173 K were smaller than those of nanofibers obtained at RT. As the amount of cerium increased, the diameter of $CeO_2$ nanofibers increased. XRD analysis revealed that the ceria nanofibers were in cubic form. TEM results revealed that the ceria nanofibers were formed by the interconnection of Ce oxide nanoparticles. The ceria nanofibers obtained at low concentrations of Ce (CeL) showed spotty ring patterns indicated that the ceria nanofibers were polycrystalline structure. And the ceria nanofibers obtained at high concentration of Ce (CeH) showed fcc (001) diffraction pattern. XPS study indicated that the oxidation of Ce shifted from $Ce^{3+}$ to $Ce^{4+}$ as the calcination temperature increased.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2004.07b
• /
• pp.1248-1253
• /
• 2004

This work describes the effect of electrode binder on the characteristics of electric double layer capacitor Among carboxymethylcellulose (CMC), Polyvinylpyrrolidone (PVP), Polyvinyl Alcohol (PVA), and Polyvinylidene Fluoride (PVDF), the unit cell using CMC showed good rate capability between $2.5mA/cm^2{\sim}100mA/cm^2$ current density. However, CMC as a binder is incongruent, because the electrode bound with CMC is rigid and easy to crack during a press and winding process for fabrication of capacitor. The unit cell capacitor using the electrode bound with binary binder composed of CMC and Polytetrafluoroethylene (PTFE), especially in composition CMC : PTFE : 60 : 40 wt.%, has exhibited the better mechanical properties than those of the unit cell with CMC. On the other hand, it was also noted that the mechanical properties of CMC+PTFE electrode, coated on underlayer composed of CMC and carbon black, were much improved the binding force.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.30 no.7
• /
• pp.441-446
• /
• 2017

Aluminum nitride fibers were synthesized by carbothermal reduction and nitridation of precursor fibers obtained by electrospinning. The starting materials used to synthesize the AlN fibers were $Al(NO_3)_3{\cdot}9H_2O$ and urea. Polyvinylpyrrolidone with increasing viscidity was used as the carbon source to obtain a composite solution. The mixed solution was drawn into a plastic syringe with a stainless steel needle, which was used as the spinneret and connected to a 20 kV power supply. A high voltage was supplied to the solution to facilitate the formation of a dense net of fibers on the collector. The precursor fibers were dried at $100^{\circ}C$ and then heated to $1,400^{\circ}C$ for 1 h in a microwave furnace under $N_2$ gas flow for the carbothermal reduction and nitridation. X-ray diffraction studies indicated that the synthesized fibers consisted of the AlN phase. Field emission scanning electron microscopy studies indicated that the diameter of the calcined fibers was approximately 100 nm.

• 한국가시화정보학회:학술대회논문집
• /
• 2007.11a
• /
• pp.105-108
• /
• 2007

To diagnose the vascular diseases from the viewpoint of hemodynamics, we need detailed quantitative hemodynamic information of related blood flows with a high spatial resolution of tens micrometer and a high temporal resolution in the order of millisecond. For investigating in-vivo hemodynamic phenomena of vascular circulatory diseases, a new diagnosing technique combining a medical radiography and PIV method was newly developed. This technique called 'Angiographic PIV system' consists of a medical X-ray tube, an X-ray CCD camera, a shutter module for generating double pulse-type X-ray, and a synchronizer. Through several preliminary tests, the feasibility of the Angiographic PIV technique was verified. For in-vivo applications to real blood flows, we developed tracer microcapsules, which were optimized to this system, made of a contrast material of iodine and a matrix material of PVA (polyvinylpyrrolidone). In near future, the Angiographic PIV technique will be used for understanding hemodynamic phenomena of vascular diseases and for their early detection.

• Membrane and Water Treatment
• /
• v.11 no.4
• /
• pp.237-245
• /
• 2020

The effects of the mixed two solvents, Dimethylacetamide (DMAc) and Dimethylformamide (DMF), and Polyethylene glycol (PEG) and Polyvinylpyrrolidone (PVP) as additives on performance of Polyvinylidene fluoride (PVDF) membranes were studied. Initially, PEG200 was used as a primary additive at fixed percentage of 5% wt. PVP was then blended with PEG200 in different concentrations. PVDF and DMAc were used as polymer and solvent in the casting solutions, respectively. To control the diffusion rate of PVP in the presence of PEG200 and PVP blend, mixtures of DMAc and DMF were used as the mixed solvent in the casting solutions. Asymmetric PVDF membranes were prepared via phase inversion process in a water bath and the effects of two additives and two solvents on the membrane morphology, pure water flux (PWF), hydrophilicity and rejection (R) were investigated. Attenuated Total Reflection Fourier Transform Infrared Spectra (ATR-FTIR) analysis was used to show the residual PVP on the surface of the membranes. Atomic Force Microscopy (AFM) was utilized to determine roughness of membrane surface. The use of mixed solvents in the casting solution resulted in reduction of PVP diffusion rate and increment of PEG diffusion rate. Eventually, PWF and R values reduced, while porosity and hydrophilicity increased.