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ABSTRACT: Bone disease can be associated with bone resorption by osteoclasts, and interest in the development of antiresorptive agents has recently increased. The hydrolysate of silk fibroin has been studied with respect to such biomedical applications. In a previous study, silk fibroin showed indirect inhibitory effects on the differentiation of osteoclasts. To further evaluate the effect of a hydrolysate of silk fibroin on osteoclasts, we investigated the direct effects of the silk fibroin hydrolysate on osteoclastogenesis and apoptosis of osteoclasts induced by receptor activation of nuclear factor κB ligand (RANKL). The silk fibroin hydrolysate inhibited RANKL-induced formation of tartrate-resistant acid phosphatase (TRAP) in RAW 264.7 cells. The inhibitory effect of the silk fibroin hydrolysate resulted in the decreased expression of osteoclast marker genes, such as matrix metalloproteinase-9 (MMP-9), cathepsin-K and calcitonin receptor (CTR). In addition, the silk fibroin hydrolysate blocked the signaling pathways of mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) and expression of transcription factors, such as nuclear factor of activated T cells c1 (NFATc1) and NF-κB. Finally, the silk fibroin hydrolysate induced apoptosis signaling cascades. Taken together, the present results indicate that silk fibroin hydrolysate has antiresorptive activity by both inhibiting osteoclastogenesis and inducing osteoclast apoptosis.
International Journal of Molecular Medicine 11/2012; 30(5):1203-10. · 1.98 Impact Factor
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ABSTRACT: The aim of this study was to access the irritant properties of bee venom (BV) after its application to skin and eye mucous membranes of the rabbit. The animals were also observed for clinical signs and mortality after the application of the test material. Six animals were used for the skin irritation test and nine rabbits for the eye irritation test. The acute BV application to the rabbit skin revealed no appreciable clinical signs throughout the observation period of 72 h and there was no mortality seen. In the eye irritation test, eye reactions were read and graded 24, 48, 72, 96 and 168 h after BV treatment. No changes in the cornea, iris or conjunctivae were observed at all time points of observations. Based on the present findings, it can be concluded that the irritation potential of BV is negligible.
The American Journal of Chinese Medicine 01/2012; 40(4):795-800. · 1.98 Impact Factor
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ABSTRACT: For cosmetic reasons, the demand for effective and safe skin-whitening agents is high. Since the key enzyme in the melanin synthetic pathway is tyrosinase, many depigmenting agents in the treatment of hyperpigmentation act as tyrosinase inhibitors. In this study, we have investigated the hypo-pigmentary mechanism of royal jelly in a mouse melanocyte cell line, B16F1. Treatment of B16F1 cells with royal jelly markedly inhibited melanin biosynthesis in a dose-dependent manner. Decreased melanin content occurred through the decrease of tyrosinase activity. The mRNA levels of tyrosinase were also reduced by royal jelly. These results suggest that royal jelly reduces melanin synthesis by down-regulation of tyrosinase mRNA transcription and serves as a new candidate in the design of new skin-whitening or therapeutic agents.
The American Journal of Chinese Medicine 01/2011; 39(6):1253-60. · 1.98 Impact Factor
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Sung Hee Nam,
Chun Ru Li,
Zeng-Zhi Li,
Mei-Zhen Fan,
Seok Woo Kang,
Kwang Gill Lee, Joo Hong Yeo,
Jae Sam Hwang,
Ji Young Choi,
Sang Mi Han,
Ki Man Lee
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ABSTRACT: Paecilomyces tenuipes reportedly have anticancer and immune activities, along with various other medicinal uses. Cultured products with P. tenuipes are certified for use in food in South Korea, and processed goods containing this fungus have been developed in many countries, particularly South Korea, Japan, and China. Research on mass production technology-procured raw materials for the manufacture of P. tenuipes is very important; however, cultures of the fungus have been unstable. This study identified stable cultivation conditions, focusing on growth inhibition and revitalization. Moisture regulation and preservation of pupae inoculated with P. tenuipes were used to control growth inhibition and revitalization. When inoculated silkworm pupae were dehydrated to 4% moisture and preserved freeze-dried or at -70 degrees C, -20 degrees C, or 4 degrees C, the mycelia in their bodies were able to survive for 14 d. Inoculated silkworm pupae were rehydrated for 3 h and the mycelia within their bodies were recovered at 94.3-96.3%. Silkworm pupae at 4% moisture were able to survive for 135 d at temperatures < 4 degrees C and for 1 y after freeze-drying. Optimal conditions for synnemata induction were 25 degrees C and 100-300 1x.
International Journal of Medicinal Mushrooms 01/2011; 13(1):83-91. · 0.89 Impact Factor
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Hyun-Jin Lee,
Chul-Hong Park,
Hyung-U Son,
Jin-Chul Heo,
Sung-Hee Nam,
Kwang-Gil Lee, Joo-Hong Yeo,
Cheol-Sik Yoon,
Jong-Myeung Kim,
Yong-Kyu Shin,
Si-Oh Kim,
Sang-Han Lee
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ABSTRACT: The aim of the present study was to investigate the anti-tumor effects of a culture filtrate of Paecilomyces farinosus J3. Various anti-tumor assays using B16 melanoma cells were carried out. Paecilomyces farinosus J3 significantly decreased the wound healing capability, invasiveness and angiogenic activity, which was confirmed by wound healing, human umbilical vein endothelial cell and invasion assays. Paecilomyces farinosus J3 strongly inhibited cell migration, tube formation and the angiogenic process in a concentration-dependent manner. Zymographic analysis also indicated a reduced expression of matrix metalloproteinase-9 (MMP-9), a 92-kDa gelatinase. Taken together, the results indicate that the anti-tumor activities of Paecilomyces farinosus J3 originate from the reduction of MMP-9 expression in B16F10 cells.
Experimental and therapeutic medicine 01/2011; 2(2):357-362.
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ABSTRACT: Antheraea pernyi silk fibroin (SF) hydrolysate were characterized using UV-VIS spectrometer, amino acid composition and heavy metal contents to explore its potential sources for food or cosmetic additives. The hydrolyzed A. pernyi SF was separated into two parts: (a) SFA, alanine-rich fraction and (b) SFB, tyrosine-rich fraction. SFB exhibited strong absorption peaks at 210 and 280 nm due to the presence of the tyrosine. Heavy metal analysis showed that arsenic and mercury did not detect. Other heavy metals, which includes lead, cadmium, etc., were recorded only a trace amount. Therefore, A. pernyi SF hydrolysate could be safely used as sources of food, cosmetic and pharmaceuticals.
International journal of biological macromolecules 10/2010; 48(1):223-6. · 2.37 Impact Factor
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ABSTRACT: This study investigated the effects of mycelial extract and culture filtrate of Cordyceps sphecocephala J201 on airway hyper-responsiveness, pulmonary immune cell infiltration, and Th2 cytokine expression in animal models of asthma. After Concanavalin A (Con A) activation of mouse primary spleen cells, the IL-4 and IL-13 cytokine expression were significantly decreased in the presence of the mycelial extract and culture filtrate of Cordyceps sphecocephala J201. The asthma model was induced by sensitization to ovalbumin by intraperitoneal (i.p.) injection treatment in mice. The Cordyceps sphecocephala J201 mycelial extract was injected in order to assess the effects of anti-asthmatic activity by comparing lung cell infiltration in ovalbumin-induced asthmatic mice. The results revealed that the increased IL-4, IL-13 and IL-25 expression were controlled by the mycelial extract and culture filtrate of Cordyceps sphecocephala J201, indicating that the extracts reduced the undesirable immune responses and/or cytokine expression exhibited in asthma.
International Journal of Molecular Medicine 09/2010; 26(3):351-6. · 1.98 Impact Factor
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Jung Hyun Park,
Yun-Jeong Jeong,
Kwan-Kyu Park,
Hyun-Ji Cho,
Il-Kyung Chung,
Kwan-Sik Min,
Mihyun Kim,
Kwang-Gill Lee, Joo-Hong Yeo,
Kwang-Kyun Park,
Young-Chae Chang
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ABSTRACT: Matrix metalloproteinase-9 (MMP-9) plays an important role in the invasion and metastasis of cancer cells. In this study, we examined the inhibitory effect of bee venom (BV) and its major peptides, melittin and apamin, on PMA-induced invasion induced by MMP-9 expression in Caki-1 renal cancer cells. BV and melittin, but not apamin, significantly suppressed PMA-induced invasion by inhibiting MMP-9 expression in Caki-1 cells. Furthermore, as evidenced by MMP-9 promoter assays, melittin inhibited MMP-9 gene expression by blocking the PMA-stimulated activations of activator protein-1 (AP-1) and nuclear factor-kappa B (NF-kappaB). In addition, melittin suppressed the PMA-induced phosphorylations of ERK and JNK mitogen-activated protein kinases, upstream factors involved in Ap-1 and NF-kappaB. These results suggest that the suppression of MMP-9 expression contributes to the anti-tumor properties of melittin.
Molecules and Cells 02/2010; 29(2):209-15. · 2.18 Impact Factor
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ABSTRACT: Silk fibroin, produced by the silkworm Bombyx mori, has been widely studied as a scaffold in tissue engineering. Although it has been shown to be slowly biodegradable, cellular responses to degraded silk fibroin fragments are largely unknown. In this study, silk fibroin was added to MG-63 cell cultures, and changes in gene expression in the MG-63 cells were screened by DNA microarray analysis. Genes showing a significant (2-fold) change were selected and their expression changes confirmed by quantitative RT-PCR and western blotting. DNA microarray results showed that alkaline phosphatase (ALP), collagen type-I alpha-1, fibronectin, and transforming growth factor-beta1 expressions significantly increased. The effect of degraded silk fibroin on osteoblastogenic gene expression was confirmed by observing up-regulation of ALP activity in MG-63 cells. The finding that small fragments of silk fibroin are able to increase the expression of osteoblastogenic genes suggests that controlled degradation of silk fibroin might accelerate new bone formation. [BMB reports 2010; 43(1): 52-56].
BMB reports 01/2010; 43(1):52-6. · 1.72 Impact Factor
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ABSTRACT: Bee venom (BV) has a long tradition of use for the control of pain and inflammation in various chronic diseases. Carbon tetrachloride (CCl4) is known to induce hepatotoxicity after being metabolized to the highly reactive trichloromethyl free radical and its peroxy radical. The purpose of the current study was to examine whether BV regulates the pro-inflammation and fibrosis related genes against a mouse model of hepatic fibrosis induced by CCl4 and ethanol-treated hepatocytes (ETH). Test mice were administered with CCl4 (2 ml/mg) and hepatocytes were treated with 25 mM ethanol. BV was added to the final concentration of 0.05-0.5 mg/kg and 1-100 ng/ml for in vivo and in vitro testing, respectively. Fibrotic livers and ETH were used for the measurement of hepatocyte necrosis, pro-inflammatory cytokines and fibrogenic genes. BV suppressed CCl4-induced hepatocyte necrosis markers of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT). It also inhibited the secretion of interleukin (IL)-1beta and tumor necrosis factor (TNF)-alpha. Moreover, BV inhibited CCl4-induced expression of transforming growth factor (TGF)-beta1, alpha-smooth muscle actin (SMA) and fibronectin. Similarly, ETH exhibited significant suppression of IL-1beta, TNF-alpha, TGF-beta1 and fibronectin when cultured with BV. These results suggest that BV possesses anti-fibrogenic properties that are mediated by the suppression of pro-inflammatory cytokines and fibrogenic gene expression. BV has substantial therapeutic potential for the treatment of fibrotic diseases.
The American Journal of Chinese Medicine 01/2010; 38(5):921-35. · 1.98 Impact Factor
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Woo-Ram Lee,
Soo-Jung Kim,
Ji-Hyun Park,
Kyung-Hyun Kim,
Young-Chae Chang,
Yoon-Yup Park,
Kwang-Gill Lee,
Sang-Mi Han, Joo-Hong Yeo,
Sok Cheon Pak,
Kwan-Kyu Park
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ABSTRACT: The components of bee venom (BV) utilized in the current study were carefully scrutinized with chromatography. Despite its well documented anti-inflammatory property, there are no reports regarding the influence of BV on the expression of cellular adhesion molecules in the vascular endothelium. A great amount of information exists concerning the effects of an atherogenic diet on atherosclerotic changes in the aorta, but little is known about the molecular mechanisms and the levels of gene regulation involved in the anti-inflammatory process induced by BV. The experimental atherosclerosis was induced in mice by a lipopolysaccharide (LPS) injection and an atherogenic diet. The animals were divided into three groups, the NC groups of animals that were fed with a normal diet, the LPS/fat group was fed with the atherogenic diet and received intraperitoneal injections of LPS, and the LPS/fat + BV group was given LPS, an atherogenic diet and intraperitoneal BV injections. At the end of each treatment period, the LPS/fat + BV group had decreased levels of total cholesterol (TC) and triglyceride (TG) in their serum, compared to the LPS/fat group. The LPS/fat group had significant expression of tumor necrosis factor (TNF)-α and interleukin (IL)-1β in the serum, compared with the NC group (p < 0.05). The amount of cytokines reduced consistently in the BV treatment groups compared with those in LPS/fat group. BV significantly reduced the amount of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), transforming growth factor-β1 (TGF-β1) and fibronectin in the aorta, compared with the LPS/fat group (p < 0.05). A similar pattern was also observed in the heart. In conclusion, BV has anti-atherogenic properties via its lipid-lowering and anti-inflammatory mechanisms.
The American Journal of Chinese Medicine 01/2010; 38(6):1077-92. · 1.98 Impact Factor
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ABSTRACT: Bee venom has been used for the treatment of inflammatory diseases such as rheumatoid arthritis and for the relief of pain in traditional oriental medicine.
The purpose of this study is to elucidate the effects of bee venom on MMP-9 expression and determine possible mechanisms by which bee venom relieves or prevents the expression of MMP-9 during invasion and metastasis of breast cancer cells. We examined the expression and activity of MMP-9 and possible signaling pathway affected in PMA-induced MCF-7 cells.
Bee venom was obtained from the National Institute of Agricultural Science and Technology of Korea. Matrigel invasion assay, wound-healing assay, zymography assay, western blot assay, electrophoretic mobility shift assay and luciferase gene assay were used for assessment.
Bee venom inhibited cell invasion and migration, and also suppressed MMP-9 activity and expression, processes related to tumor invasion and metastasis, in PMA-induced MCF-7 cells. Bee venom specifically suppressed the phosphorylation of p38/JNK and at the same time, suppressed the protein expression, DNA binding and promoter activity of NF-kappaB. The levels of phosphorylated ERK1/2 and c-Jun did not change. We also investigated MMP-9 inhibition by melittin, apamin and PLA(2), representative single component of bee venom. We confirmed that PMA-induced MMP-9 activity was significantly decreased by melittin, but not by apamin and phospholipase A(2). These data demonstrated that the expression of MMP-9 was abolished by melittin, the main component of bee venom.
Bee venom inhibits PMA-induced MMP-9 expression and activity by inhibition of NF-kappaB via p38 MAPK and JNK signaling pathways in MCF-7 cells. These results indicate that bee venom can be a potential anti-metastatic and anti-invasive agent. This useful effect may lead to future clinical research on the anti-cancer properties of bee venom.
Journal of ethnopharmacology 12/2009; 127(3):662-8. · 2.32 Impact Factor
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Kwang-Gill Lee,
Hyun-Ji Cho,
Young-Seuk Bae,
Kwan-Kyu Park,
Jung-Yoon Choe,
Il-Kyung Chung,
Mihyun Kim, Joo-Hong Yeo,
Kyung-Ho Park,
Yun-Sik Lee,
Cheorl-Ho Kim,
Young-Chae Chang
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ABSTRACT: Bee venom (BV) is a traditional Korean medicine that has been widely used with satisfactory results in the treatment of some immune-related diseases, especially rheumatoid arthritis.
The purpose of this study is to elucidate the molecular mechanism underlying the anti-inflammatory effects of BV, which is used in the treatment of various inflammatory diseases in traditional Korean medicine. We evaluated the anti-inflammatory effect of BV on NO generation and iNOS expression by LPS in rat C6 glioma cells.
BV was obtained from the National Institute of Agricultural Science and Technology (NIAST) of Korea. Nitrite measurement, Immuno blot analysis, Reverse transcriptase-PCR and Electrophoretic mobility shift assay (EMSA) were used for assessment.
BV suppressed the LPS-induced NO generation and iNOS expression, and it also inhibited the expressions of LPS-induced pro-inflammatory molecules including Cox-2 and IL-1 beta in rat C6 glioma cells. Then, BV inhibited LPS-induced expression of PKC-alpha and MEK/ERK, not p38 and JNK. Moreover, inhibition of LPS-induced iNOS expression by BV was dependent on transcriptional activities of AP-1/NF-kappaB through MEK/ERK pathway.
These results indicate that BV suppresses LPS-induced iNOS activation through regulation of PKC-alpha. Accordingly, BV exerts a potent suppressive effect on pro-inflammatory responses in rat C6 glioma cells.
Journal of ethnopharmacology 06/2009; 123(1):15-21. · 2.32 Impact Factor
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ABSTRACT: This study examined the effect of whole bee venom (BV) as a potential stimulant of the piglet immune system, on growth performance, blood parameters, plasma protein and immune globulin content of serum. Piglets (n = 97) received combinations of 0.5, 1.0, 1.5, 2.0 and 2.5 mg/kg of parenterally administered BV on 4 occasions between birth and Day 30. In the apipuncture group (n = 31), piglets were acupunctured with the worker honeybee. Two acupoints, GV-1 (Jiao-chao) and GV-20 (Bai-hui), were selected for apipuncture. All piglets (n = 128) in the treatment groups were treated 4 times throughout the study period of 60 days. The control piglets received no treatments. Blood was taken via jugular venipuncture on Day 30 after birth. Body weight and survivability were measured, and changes in hematological values were analyzed. Both the BV injection group and apipuncture group increased body weight and survivability by 26.6% and 21.8%, and 7.9% and 6.7% respectively compared to the controls. The numbers of leukocytes, erythrocytes, lymphocytes and monocytes were not influenced by treatments. However, a potential clinical benefit of high dose therapy was seen in increased populations of leukocytes, lymphocytes and monocytes compared with either the apipuncture or control groups. Other blood parameters such as total protein and albumin were not affected by treatment. However, IgG levels were generally higher in treated groups than in the controls. These findings indicate that BV might be useful to stimulate immuno-competence in pig production, possibly via the primary bioactive components of melittin, phospholipase A(2) and apamin. The administration of BV, either via injection or acupuncture, did not make any differences in growth performance of young pigs. These results would be useful for further purification and characterization of immune boosting agents from BV.
The American Journal of Chinese Medicine 02/2009; 37(2):253-60. · 1.98 Impact Factor
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ABSTRACT: Semi-interpenetrating polymer networks (SIPNs) composed of silk fibroin (SF) and poly(ethylene glycol) (PEG) were prepared by photopolymerization of a PEG macromer in the presence of SF to improve the mechanical properties of SF sponge as wound dressing. The morphological structure of the SF/PEG SIPNs was observed to be composed of an interconnected microporous surface and a cross-sectional area. SF/PEG SIPNs showed non-cytotoxicity evaluated by a cell proliferation method using L929 fibroblasts. Wound contraction treated with SF/PEG SIPNs sponges was faster than that of Vaseline gauze as a control. Histological observation confirmed that the deposition of collagen in the dermis was organized by covering the wound area with SF/PEG SIPNs. The above results indicated that SF/PEG SIPNs could be used as wound dressing.
Biomedical Materials 10/2008; 3(3):034115. · 2.16 Impact Factor
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Hyun-Ji Cho,
Tae-Sung Lee,
Jae-Bok Park,
Kwan-Kyu Park,
Jung-Yoon Choe,
Doo-Il Sin,
Yoon-Yub Park,
Yong-Suk Moon,
Kwang-Gill Lee, Joo-Hong Yeo,
Sang-Mi Han,
Young-Su Cho,
Myeong-Rak Choi,
Nam-Gyu Park,
Yun-Sik Lee,
Young-Chae Chang
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ABSTRACT: Cancer cells, characterized by local invasion and distant metastasis, are very much dependent on the extracellular matrix. The expression of matrix metalloproteinases (MMPs) has been implicated in the invasion and metastasis of cancer cells. In this study, we reported the effects of disulfiram, a clinically used anti-alcoholism drug, on tumor invasion suppression, as well as its effects on the activity of MMP-2 and MMP-9 in human osteosarcoma cells (U2OS). Disulfiram has been used for alcohol aversion therapy. However, recent reports have shown that disulfiram may have potential in the treatment of human cancers. Herewith, we showed that the anti-tumor effects of disulfiram, in an invasion assay using U2OS cells and that disulfiram has a type IV collagenase inhibitory activity that inhibits expression of genes and proteins responsible for both cell and non-cell mediated invasion on pathways. In conclusion, disulfiram inhibited expression of MMP-2 and MMP-9 and it regulated the invasion of human osteosarcoma cells. These observations raise the possibility of disulfiram being used clinical for the inhibition of cancer invasion.
Journal of biochemistry and molecular biology 12/2007; 40(6):1069-76. · 2.02 Impact Factor
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ABSTRACT: Silk fibroin/alginate blend sponges were examined through IR spectroscopy, X-ray diffractometry, and differential scanning calorimetry to determine the structural changes of silk fibroin. The effects of fibroin/alginate blend ratios on the physical and mechanical properties were investigated to discover the feasibility of using these blend sponges as biomedical materials such as wound dressings. The compressive modulus of silk fibroin was increased up to 30 kPa, from 7.1 kPa, by blending with alginate. Thermal crystallization behavior of fibroin induced by heat treatment was restricted by blending with alginate. In spite of that, the structural characteristics of fibroin were not changed by incorporation with alginate. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 2174–2179, 2004
Journal of Applied Polymer Science 06/2004; 93(5):2174 - 2179. · 1.29 Impact Factor
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ABSTRACT: Activated microglia extensively produce nitric oxide (NO) by inducing expression of inducible NO synthase (iNOS). NO plays a deleterious role in brain inflammation and neuronal death. In the present study, we investigated the effects of 1,3-selenazol-4-one derivatives (Sz-A, B, C, D and E) on NO production and iNOS expression in lipopolysaccharide (LPS)-induced BV-2 cells, a murine microglia cell line. Among these compounds, Sz-B and C remarkably inhibited LPS-induced NO production relative to that of Sz-A, D, and E at 5 microM in BV-2 cells. Sz-B and C dose-dependently inhibited NO production at 1, 5, and 10 microM without toxicity to BV-2 cells. Sz-B and C also dose-dependently suppressed iNOS expression at the same concentrations in LPS-induced BV-2 cells. This result suggests that Sz-B and C inhibit iNOS-mediated NO production in LPS-induced BV-2 cells. Structurally, Sz-B and C bear an ethyl or methyl group at the 5 positions of the 4-selenazolone skeletons, which could play an important role in inhibiting iNOS-mediated NO production.
Biological & Pharmaceutical Bulletin 01/2004; 26(12):1657-60. · 1.66 Impact Factor
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ABSTRACT: Effects of methyl alcohol on the morphology and conformational characteristics of silk sericin (SS) were studied. Scanning electron microscope showed that morphology of SS lyophilized was dramatically changed from sponge-like structure to spherical fine particle type. X-ray diffraction method, infrared spectroscopy, and differential scanning calorimetry showed that the conformation of SS was random coil structure regardless of the addition of methyl alcohol. On the other hand, circular dichroism showed that the molecular states of SS were more densely packed.
International Journal of Biological Macromolecules 12/2003; 33(1-3):75-80. · 2.45 Impact Factor
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ABSTRACT: Silk sericin (SS) possessing moisture-retaining property was reacted with activated poly(ethylene glycol) (PEG) to obtain self-assembled SS nanoparticles. The aliphatic and aromatic hydroxyl groups of serine and tyrosine residues as the reaction sites in SS were clarified by amino acid analysis and 1H NMR spectroscopy, respectively. From IR and circular dichroism (CD) measurements, introduction of PEG into SS induced the conformational change from random coil to beta-sheet. DSC thermogram of sericin-PEG conjugate suggests that mutual miscibility between PEG and SS chains was poor. Nanoparticles of sericin-PEG conjugate with sizes measured by dynamic light scattering ranging about 200-400 nm in diameter, were prepared by the diafiltration method. Shape of sericin-PEG conjugate nanoparticles observed by scanning and transmission electron microscopes was spherical. The results suggest that sericin-PEG conjugates are self-associated to form spherical nanoparticles through hydrophobic interaction.
International Journal of Biological Macromolecules 04/2003; 32(1-2):36-42. · 2.45 Impact Factor
