Publications by authors named "Taehee Han"

12 Publications

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Coping with large litters: management effects on welfare and nursing capacity of the sow.

J Anim Sci Technol 2021 Mar 31;63(2):199-210. Epub 2021 Mar 31.

Department of Animal Science, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 61186, Korea.

A number of management issues can be used as drivers for change in order to improve animal welfare and nursing capacity of the hyperprolific sow. Group housing of sows during gestation is a recommended practice from the perspective of animal welfare. Related health issues include reproductive health and the locomotor system. It appears that management of pregnant sows in groups is challenging for a producer and considerable skill is required. We explored the benefits and challenges of group housing, including feeding issues. Increasing litter size requires additional attention to the mammary gland and its ability to provide sufficient nursing for the growing litter. We discuss the fundamentals of mammary development and the specific challenges related to the hyperprolific sow. We also address challenges with the farrowing environment. It appears that the old-fashioned farrowing crate is not only outdated in terms of welfare from the public's perspective, but also fails to provide the environment that the sow needs to support her physiology of farrowing, nursing, and maternal behaviour. Studies from our group and others indicate that providing the sow with a loose housing system adequate in space and nesting material, along with reasonable chance for isolation, can be considered as fundamental for successful farrowing of the hyperprolific sow. It has also been shown that management strategies, such as split suckling and cross fostering, are necessary to ensure proper colostrum intake for all piglets born alive in a large litter. We thus conclude that welfare and nursing capacity of the sow can be improved by management. However, current megatrends such as the climate change may change sow management and force the industry to rethink goals of breeding and, for instance, breeding for better resilience may need to be included as goals for the future.
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http://dx.doi.org/10.5187/jast.2021.e46DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8071737PMC
March 2021

Coping with large litters: the management of neonatal piglets and sow reproduction.

J Anim Sci Technol 2021 Jan 31;63(1):1-15. Epub 2021 Jan 31.

Department of Production Animal Medicine, Faculty of Veterinary Medicine, University of Helsinki, Saarentaus 04920, Finland.

As a result of intensive breeding, litter size has considerably increased in pig production over the last three decades. This has resulted in an increase in farrowing complications. Prolonged farrowing will shorten the window for suckling colostrum and reduce the chances for high-quality colostrum intake. Studies also agree that increasing litter sizes concomitantly resulted in decreased piglet birth weight and increased within-litter birth weight variations. Birth weight, however, is one of the critical factors affecting the prognosis of colostrum intake, and piglet growth, welfare, and survival. Litters of uneven birth weight distribution will suffer and lead to increased piglet mortality before weaning. The proper management is key to handle the situation. Feeding strategies before farrowing, management routines during parturition (e.g., drying and moving piglets to the udder and cross-fostering) and feeding an energy source to piglets after birth may be beneficial management tools with large litters. Insulin-like growth factor 1 (IGF-1)-driven recovery from energy losses during lactation appears critical for supporting follicle development, the viability of oocytes and embryos, and, eventually, litter uniformity. This paper explores certain management routines for neonatal piglets that can lead to the optimization of their colostrum intake and thereby their survival in large litters. In addition, this paper reviews the evidence concerning nutritional factors, particularly lactation feeding that may reduce the loss of sow body reserves, affecting the growth of the next oocyte generation. In conclusion, decreasing birth weight and compromised immunity are subjects warranting investigation in the search for novel management tools. Furthermore, to increase litter uniformity, more focus should be placed on nutritional factors that affect IGF-1-driven follicle development before ovulation.
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http://dx.doi.org/10.5187/jast.2021.e3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7882835PMC
January 2021

Glutaric acid production by systems metabolic engineering of an l-lysine-overproducing .

Proc Natl Acad Sci U S A 2020 12 16;117(48):30328-30334. Epub 2020 Nov 16.

Metabolic and Biomolecular Engineering National Research Laboratory, Systems Metabolic Engineering and Systems Healthcare Cross-Generation Collaborative Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Plus Program), Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Yuseong-gu, 34141 Daejeon, Republic of Korea;

There is increasing industrial demand for five-carbon platform chemicals, particularly glutaric acid, a widely used building block chemical for the synthesis of polyesters and polyamides. Here we report the development of an efficient glutaric acid microbial producer by systems metabolic engineering of an l-lysine-overproducing BE strain. Based on our previous study, an optimal synthetic metabolic pathway comprising l-lysine monooxygenase () and 5-aminovaleramide amidohydrolase () genes and 4-aminobutyrate aminotransferase () and succinate-semialdehyde dehydrogenase () genes, was introduced into the BE strain. Through system-wide analyses including genome-scale metabolic simulation, comparative transcriptome analysis, and flux response analysis, 11 target genes to be manipulated were identified and expressed at desired levels to increase the supply of direct precursor l-lysine and reduce precursor loss. A glutaric acid exporter encoded by was discovered and overexpressed to further enhance glutaric acid production. Fermentation conditions, including oxygen transfer rate, batch-phase glucose level, and nutrient feeding strategy, were optimized for the efficient production of glutaric acid. Fed-batch culture of the final engineered strain produced 105.3 g/L of glutaric acid in 69 h without any byproduct. The strategies of metabolic engineering and fermentation optimization described here will be useful for developing engineered microorganisms for the high-level bio-based production of other chemicals of interest to industry.
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http://dx.doi.org/10.1073/pnas.2017483117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7720191PMC
December 2020

Mealworm ( Larvae) as an Alternative Protein Source for Monogastric Animal: A Review.

Animals (Basel) 2020 Nov 8;10(11). Epub 2020 Nov 8.

Department of Agricultural Biotechnology, and Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 08826, Korea.

Edible insects have been used as an alternative protein source for food and animal feed, and the market size for edible insects has increased. larvae, also known as mealworm and yellow mealworm, are considered a good protein source with nutritional value, digestibility, flavor, and a functional ability. Additionally, they are easy to breed and feed for having a stable protein content, regardless of their diets. Therefore, larvae have been produced industrially as feed for pets, zoo animals, and even for production animals. To maintain the nutrient composition and safety of larvae, slaughtering (heating or freezing) and post-slaughtering (drying and grinding) procedures should be improved for animal feed. larvae are also processed with defatting or hydrolysis before grinding. They have a high quality and quantity of protein and amino acid profile, so are considered a highly sustainable protein source for replacing soybean meal or fishmeal. has a chitin in its cuticle, which is an indigestible fiber with positive effects on the immune system. In studies of poultry, the supplementation of larvae improved the growth performance of broiler chickens, without having negative effects on carcass traits, whereas some studies have reported that there were no significant differences in the growth performance and carcass yield of broiler chickens. In studies of swine, the supplementation of larvae improved the growth performance and protein utilization of weaning pigs. Furthermore, 10% of larvae showed greater amino acid digestibility than conventional animal proteins in growing pigs. However, there are some challenges regarding the biosafety, consumer's acceptance, and price for the use of larvae in animal feed. Consequently, larvae could be used as an alternative or sustainable protein source in monogastric animal feed with a consideration of the nutritional values, biosafety, consumer's acceptance, and market price of larvae products.
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http://dx.doi.org/10.3390/ani10112068DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7695176PMC
November 2020

Tools and strategies of systems metabolic engineering for the development of microbial cell factories for chemical production.

Chem Soc Rev 2020 Jul;49(14):4615-4636

Metabolic and Biomolecular Engineering National Research Laboratory, Systems Metabolic Engineering and Systems Healthcare (SMESH) Cross-Generation Collaborative Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Plus Program), Institute for the BioCentury, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea. and Bioinformatics Research Center, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea and BioProcess Engineering Research Center, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea.

Sustainable production of chemicals from renewable non-food biomass has become a promising alternative to overcome environmental issues caused by our heavy dependence on fossil resources. Systems metabolic engineering, which integrates traditional metabolic engineering with systems biology, synthetic biology, and evolutionary engineering, is enabling the development of microbial cell factories capable of efficiently producing a myriad of chemicals and materials including biofuels, bulk and fine chemicals, polymers, amino acids, natural products and drugs. In this paper, many tools and strategies of systems metabolic engineering, including in silico genome-scale metabolic simulation, sophisticated enzyme engineering, optimal gene expression modulation, in vivo biosensors, de novo pathway design, and genomic engineering, employed for developing microbial cell factories are reviewed. Also, detailed procedures of systems metabolic engineering used to develop microbial strains producing chemicals and materials are showcased. Finally, future challenges and perspectives in further advancing systems metabolic engineering and establishing biorefineries are discussed.
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http://dx.doi.org/10.1039/d0cs00155dDOI Listing
July 2020

Avoiding student infection during a Middle East respiratory syndrome (MERS) outbreak: a single medical school experience.

Korean J Med Educ 2016 Jun 27;28(2):209-17. Epub 2016 May 27.

Department of Molecular Cell Biology, Sungkyunkwan University School of Medicine, Suwon, Korea.

Purpose: In outbreaks of infectious disease, medical students are easily overlooked in the management of healthcare personnel protection although they serve in clinical clerkships in hospitals. In the early summer of 2015, Middle East respiratory syndrome (MERS) struck South Korea, and students of Sungkyunkwan University School of Medicine (SKKUSOM) were at risk of contracting the disease. The purpose of this report is to share SKKUSOM's experience against the MERS outbreak and provide suggestions for medical schools to consider in the face of similar challenges.

Methods: Through a process of reflection-on-action, we examined SKKUSOM's efforts to avoid student infection during the MERS outbreak and derived a few practical guidelines that medical schools can adopt to ensure student safety in outbreaks of infectious disease.

Results: The school leadership conducted ongoing risk assessment and developed contingency plans to balance student safety and continuity in medical education. They rearranged the clerkships to another hospital and offered distant lectures and tutorials. Five suggestions are extracted for medical schools to consider in infection outbreaks: instant cessation of clinical clerkships; rational decision making on a school closure; use of information technology; constant communication with hospitals; and open communication with faculty, staff, and students.

Conclusion: Medical schools need to take the initiative and actively seek countermeasures against student infection. It is essential that medical schools keep constant communication with their index hospitals and the involved personnel. In order to assure student learning, medical schools may consider offering distant education with online technology.
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http://dx.doi.org/10.3946/kjme.2016.30DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4951746PMC
June 2016

[Humanities in medical education: between reduction and integration].

Authors:
Taehee Han

Korean J Med Educ 2015 Sep 26;27(3):163-5. Epub 2015 Aug 26.

Department of Medical Education, Sungkyunkwan University School of Medicine, Suwon, Korea.

Reductive logic has been a major reasoning style in development of modern biomedical sciences. However, when "medical humanities" is developed by reductive reasoning, integrative and holistic values of humanities tend to be weakened. In that sense, identity and significance of "medical humanities" continue to be controversial despite of its literal clarity. Humanities in medical education should be established by strengthening humanistic and socialistic aspects of regular medical curriculum as well as developing individual "medical humanities" programs.
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http://dx.doi.org/10.3946/kjme.2015.27.3.163DOI Listing
September 2015

New intrastromal corneal reshaping procedure using high-intensity femtosecond laser pulses.

J Cataract Refract Surg 2015 Jun 19;41(6):1137-44. Epub 2015 Jun 19.

From the Department of Mechanical and Aerospace Engineering (Han, Suckewer), Princeton University, Princeton, and the Cornea and Laser Eye Institute (Hersh), Hersh Vision Group, Teaneck, New Jersey, USA; the State Key Laboratory of Precision Spectroscopy (Li), East China Normal University, Shanghai, China.

Unlabelled: A minimally invasive keratorefractive procedure using high-intensity, low-energy femtosecond laser pulses to perform intrastromal ablation is described. Because of the low pulse energy and the ultrashort duration, tissue in the corneal stroma can be ablated with almost no heat or shockwave generation. This technique obviates the need for the laser in situ keratomileusis (LASIK) flap but retains the advantages of the LASIK procedure. In the technique, a series of femtosecond laser pulses create temporary microchannels in the stroma, oriented perpendicular to the eye's optical axis. After the microchannels are created, a second series of femtosecond pulses directly ablate the desired amount of stromal tissue in a controlled fashion. The ablated material is ejected from the microchannels so the surface layer above the ablated regions collapses, with a consequent change in the refractive power of the cornea.

Financial Disclosure: No author has a financial or proprietary interest in any material or method mentioned.
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http://dx.doi.org/10.1016/j.jcrs.2015.05.008DOI Listing
June 2015

Platinum supported on titanium-ruthenium oxide is a remarkably stable electrocatayst for hydrogen fuel cell vehicles.

Proc Natl Acad Sci U S A 2014 Jan 23;111(1):45-50. Epub 2013 Dec 23.

Center for Electrochemical Science and Engineering, Department of Chemical and Biological Engineering, Illinois Institute of Technology, Chicago, IL 60616.

We report a unique and highly stable electrocatalyst-platinum (Pt) supported on titanium-ruthenium oxide (TRO)-for hydrogen fuel cell vehicles. The Pt/TRO electrocatalyst was exposed to stringent accelerated test protocols designed to induce degradation and failure mechanisms identical to those seen during extended normal operation of a fuel cell automobile-namely, support corrosion during vehicle startup and shutdown, and platinum dissolution during vehicle acceleration and deceleration. These experiments were performed both ex situ (on supports and catalysts deposited onto a glassy carbon rotating disk electrode) and in situ (in a membrane electrode assembly). The Pt/TRO was compared against a state-of-the-art benchmark catalyst-Pt supported on high surface-area carbon (Pt/HSAC). In ex situ tests, Pt/TRO lost only 18% of its initial oxygen reduction reaction mass activity and 3% of its oxygen reduction reaction-specific activity, whereas the corresponding losses for Pt/HSAC were 52% and 22%. In in situ-accelerated degradation tests performed on membrane electrode assemblies, the loss in cell voltage at 1 A · cm(-2) at 100% RH was a negligible 15 mV for Pt/TRO, whereas the loss was too high to permit operation at 1 A · cm(-2) for Pt/HSAC. We clearly show that electrocatalyst support corrosion induced during fuel cell startup and shutdown is a far more potent failure mode than platinum dissolution during fuel cell operation. Hence, we posit that the need for a highly stable support (such as TRO) is paramount. Finally, we demonstrate that the corrosion of carbon present in the gas diffusion layer of the fuel cell is only of minor concern.
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http://dx.doi.org/10.1073/pnas.1319663111DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3890802PMC
January 2014

Regulation of TGF-β signaling by PKC depends on Tsc-22 inducibility.

Mol Cell Biochem 2012 Jan 1;360(1-2):47-50. Epub 2011 Sep 1.

Department of Molecular Cell Biology, SBRI, Sungkyunkwan University School of Medicine, Suwon, Republic of Korea.

Interactions between various signaling pathways enable a fine control of cellular activities. When the cells are subjected to activation of TGF-β signaling and PKC signaling, PKC phosphorylation of Smad3 abrogates binding and transcriptional activity of Smad3 leading to suppression of TGF-β response. We studied this interaction between Smads and PKC in different cell types to examine cell specificity of the interaction. We found that the outcome of the interaction between Smads and PKC depends on cell types and inducibility of a regulatory molecule Tsc-22. In this report, we showed that induced Tsc-22 leads to enhancement of TGF-β-dependent signaling and the enhancement was blocked by expression of a dominant-negative Tsc-22 mutant. Its effect on cellular differentiation was also examined.
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http://dx.doi.org/10.1007/s11010-011-1042-8DOI Listing
January 2012

Structural and functional characterization of soluble endoglin receptor.

Biochem Biophys Res Commun 2009 Jun 5;383(4):386-91. Epub 2009 Mar 5.

Department of Molecular Cell Biology, Samsung Biomedical Research institute, Sungkyunkwan University School of Medicine, 300 Chunchun-Dong, Suwon 440-746, Republic of Korea.

Endoglin, an accessory membrane receptor of transforming growth factor-beta (TGF-beta)1, modulates the cellular response to TGF-beta via its interaction with type I and II TGF-beta receptors. It has been considered a promising target for the development of therapeutics and cancer markers. We have established stable CHO cell lines that efficiently secrete soluble endoglin (s-endoglin) fused with human growth hormone. Two oligomeric forms were observed in a homogeneous preparation of s-endoglin, as a dimer and a tetramer. The dimeric s-endoglin enhanced TGF-beta responsiveness in U937 cells, thus proving its potential for therapeutic applications. Small angle X-ray scattering (SAXS) experiments revealed elongated conformations of both dimeric and tetrameric s-endoglins in solution, suggesting that s-endoglin might undergo conformational adaptations upon TGF-beta binding. The current results provide important references and material for high-resolution structural studies and for medical applications of s-endoglin.
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http://dx.doi.org/10.1016/j.bbrc.2009.02.162DOI Listing
June 2009

Effect of pH on radiation-induced p53 expression.

Int J Radiat Oncol Biol Phys 2004 Nov;60(4):1264-71

Department of Therapeutic Radiology, College of Medicine, University of Ulsan, Seoul, Korea.

Purpose: In most tumors, the intratumor environment is acidic. The purpose of this study was to elucidate the effect of acidic extracellular environment on the radiation-induced expression of p53 and related molecular signals.

Methods And Materials: Cultured RKO.C human colorectal cancer cells carrying wild-type p53 were used. Cells grown in pH 7.5 medium or pH 6.6 medium were irradiated with gamma-rays, and the expression of p53 and p53 mRNA, as well as the degradation rate of the molecules, was determined. The transcriptional activity for p53 was investigated using cells transfected with a p53 reporter construct. The expression of Mdm2 and the phosphorylation of p53, essential factors for p53 degradation, were also investigated.

Results: The pH 6.6 environment prolonged the radiation-induced expression of p53 and p53 mRNA. The radiation-induced increase in transcriptional activity of p53 lasted longer in pH 6.6 medium than in pH 7.5 medium. The degradation of p53 was delayed at pH 6.6. The radiation-induced expression of Mdm2 was markedly suppressed, whereas the phosphorylation of p53 was markedly increased after irradiation in pH 6.6 medium.

Conclusion: Acidic environment significantly enhances the radiation-induced expression of p53, partly by increasing the formation of p53 and also partly by slowing down the degradation of p53 through inhibiting p53-Mdm2 complex formation. The potential implication of acidic intratumor microenvironment for the response of tumors to radiotherapy remains to be elucidated.
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http://dx.doi.org/10.1016/j.ijrobp.2004.04.043DOI Listing
November 2004