A New Method of Gelatin Modified Collagen and Viscoelastic Study of Gelatin-Collagen Composite Hydrogel

Lang He,Sheng Li,Chengzhi Xu,Benmei Wei,Juntao Zhang,Yuling Xu,Beirong Zhu,Yang Cao,Xilin Wu,Zhijin Xiong,Rongrui Huang,Jian Yang,Haibo Wang 한국고분자학회 2020 Macromolecular Research Vol.28 No.9

Pure collagen materials are expensive with poor mechanical properties, which need modifications in most cases. As the degradation product of collagen, gelatin is cheap, degradable and biocompatible, but few literatures have reported the research about gelatin-collagen composite materials. This is because gelatin and collagen have different soluble temperatures—gelatin is soluble in hot water (≥30 oC) and swells in cold water. However, a low temperature (2-10 oC) is required to prepare and store collagen solution, and neutral collagen solution denatures quickly above the room temperature. In this study, gelatin was ground into powders and swelled in neutral bovine tendon pepsin-soluble collagen solution (BPSC) to form a homogeneous gelatin-collagen mixture, in light of the swelling characteristics of gelatin in cold water. The assembly properties and gel properties of this composite material were further studied. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) test results showed that the bovine tendon collagen had typical type-I collagen structural characterizations with two α chains of about 100 kDa and one β chain of about 200 kDa; while the SDS-PAGE pattern of gelatin displayed bands continuously distributed from 30 to 200 kDa. Amino acid composition analysis test indicated that the content of polar amino acids and the sum of acidic and base amino acids for gelatin were higher than that of BPSC. Studies on gel properties demonstrated that gelatin-collagen mixed solution had collagenlike assembly characteristics and assembly kinetics. The moduli of the assembled gel at 35 oC were equivalent to that of pure bovine tendon collagen system; moreover, the system moduli didn’t change with time with elastic moduli (G') of about 40 Pa. However, at 25 oC, the moduli of gelatin-collagen composite hydrogel increased with the extension of time, its G' increased about 18 times within 8 h, and the ratio of elastic modulus to viscous modulus (G'') increased 4.6 times, showing a significant aging effect of structural strength. Meanwhile, the mechanical strength of the composite hydrogel was also regulated by temperature—the gel was highly elastic (G'≈3,000 Pa, G'>>G'') at a low temperature (5 oC); as the temperature rose, the system moduli gradually decreased and the elastic gel transformed into waterlike fluid at 50 oC little by little. What’s more, gelatin-collagen composite hydrogel also had reversible sol-gel performances and self-healing capability similar to the gelatin hydrogel. This novel preparation method for preparing composite materials and the resultant composite hydrogel are expected to be used in the fields of natural food gels, injectable hydrogels, cell scaffolds, drug sustained-release materials and so on, and improve and promote the processing performances, price and large-scale production of collagen-based materials.

일수벌금제 도입의 구체적 입법방향

양랑해(Yang Lang Hae) 한국형사법학회 2017 刑事法硏究 Vol.29 No.3

본 논문은 벌금형이 그 목적과 정당성을 충분히 달성하고, 형벌로서 실질적 평등이 구현될 수 있도록 일수벌금제 도입을 역설하고, 이에 대한 다양한 입법적 방향성을 고찰한 결과이다. 벌금형에 있어서 일수벌금제의 도입, 개인의 경제상황에 따라 벌금액수를 달리하는 것은 아주 오래전부터 최대의 딜레마였다. 그동안 발표되었던 다수의 논문이나 국회에 제출되었던 상당수 입법안, 각종 언론 등에서 짐작할 수 있듯이, 그 동안 우리는 일수벌금제의 도입을 상당히 원하고 추진해왔다고 할 수 있다. 다른 법률과의 관계 및 경제상황 조사 등 현실적인 문제로 인해 그 동안 도입하지 못했던 것 뿐이지, 도입하고 싶지 않아서가 아니었다. 기존의 다수의 선행 연구들이, 일수벌금제 도입여부에 대한 논의에만 급급하거나, 일부 편면적 입법 방향성만 논했던 것에 그쳤다면, 본 논문은 도입을 전제로 하되 과연 구체적으로 어떻게 도입할 것인지에 대해서 문제되었던 주요 쟁점별로 논증한 것이 특징이다. 다른 법률들의 관계 등을 고려하여 과연 어떻게 도입하는 것이 타당하고 합리적인지, 그동안 제시되었던 다양한 문제점들을 어떻게 입법에 투영할 것인지, 직접적인 규정은 어떻게 바뀌어야 하는지 구체적인 입법 방향에 대하여 비교법적 연구 등을 통해 종합적으로 검토하고자 하였다. 본 논문에서 언급한 쟁점으로는 (1) 일수벌금제의 전면·부분시행 여부, (2) 최저·최대일수설정, (3) 일수산정기준 내지 벌금형의 독립적 양형기준 마련, (4) 일수정액 한도 설정, (5) 일수벌금액 산정의 기초, (6) 피고인의 경제적 상황 조사방법 (7) 법정형의 일수형태로의 변경, (8) 과료폐지와 벌금형 단일화, (9) 확정후 일수정액 조정절차 마련, (10) 일수에 따른 벌금 납부기간의 변경, (11) 납부시기에 따른 벌금 할인·할증방안 등이다. 새로운 정부는 종합적인 검토를 통해 규정상의 미비와 제도상 미흡한 부분에 대한 대안을 모색하고 이를 과감하게 시도해 나가는 적극적 노력이 필요할 것이며, 일수벌금제를 도입하여 형벌분야에 있어서 우리나라의 최대의 개혁을 이루었으면 한다. This paper emphasizes the introduction of Day-fine system for the realization of substantive equality so that the punishment can achieve the purpose and justification as punishment, and it examines various legislative direction. The introduction of Day-fine system concerning fines, that is to say, to vary the amount of fines depending on the individual s economic situation, has been the greatest dilemma since long ago. As many papers published in the past, and a lot of legislative proposals have been submitted to the National Assembly, and various media reports, we can say that we have been pushing for the introduction of Day-fine system constantly. It was not because We did not want to introduce it because of the real problems, such as difficulties in investigating the individual s economic situation and relations with other acts. Many of the previous studies that have been published in the past have only focused on discussing whether to introduce the day-fine system or only discussing some aspects of legislative direction. However, this paper is characterized by the fact that it has been argued by the major issues that have been questioned about how to introduce concretely on the assumption of introduction. Taking into account the relationships of other laws, and how to introduce fair and reasonable that really? How will the legislation reflects the various problems that have been presented so far? And how to revise specific regulations, etc. I have tried to review the specific legislative direction in this paper comprehensively. The issues mentioned in this paper are (1) overall/partial enforcement of the day-fine system, (2) setting minimum and maximum number of days, (3) establishment of independent sentencing guideline for calculating the number of days or fines, (4) setting range of amount of day-fine, (5) basis for calculating the day-fine, (6) how to investigate the defendant s economic circumstances, (7) Switching to the number of days in the statutory punishment, (8) abolition of minor fine as the penal sanction and, Unification of fines, (9) after settlement of judgment, adjustment of amount of day-fine, (10) resetting fine payment period, (11) fines discount and increase method according to time of payment, etc. The new government of Korea should make comprehensive efforts to find alternatives to the inadequacy of regulations and insufficient parts of the system, and actively try to boldly try them out. So, by introducing day-fine system, the greatest reforms in criminal punishments should be made in Korea.

Design of potent, non-toxic anticancer peptides based on the structure of the antimicrobial peptide, temporin-1CEa

Qing-Zhu Yang,Che Wang,Lei Lang,Yang Zhou,He Wang,De-Jing Shang 대한약학회 2013 Archives of Pharmacal Research Vol.36 No.11

Recent advances in the search for novel anticanceragents have indicated that the positively chargedantimicrobial peptides have emerged as promising agentsoffering several advantages over the conventional anticancerdrugs. As a naturally occurring, cationic, a-helicalantimicrobial peptide, temproin-1CEa has been proved toexhibit a potent anticancer effect and a moderate hemolyticactivity. In order to reduce the hemolytic activity of temporin-1CEa and improve its anticancer potency towards arange of human breast cancer cells, in the present study, sixanalogs of temporin-1CEa were rationally designed andsynthesized. The amphipathicity levels and a-helicalstructural patterns of peptides were reserved, while theircationic property and hydrophobicity were changed. Theresults of MTT and hemolysis assay indicated that theanalog peptides displayed an improved anticancer activityand showed an overall optimized therapeutic index. Thehydrophobicity of peptides was positively correlated withtheir hemolytic and antitumor activities. Moreover, the datasuggest a strategy of increasing the cationicity whilemaintaining the moderate hydrophobicity of naturallyoccurring amphipathic a-helical peptides to generate analogswith improved cytotoxicity against tumor cells butdecreased activity against non-neoplastic cells such ashuman erythrocytes. This work highlights the potential forrational design and synthesis of improved antimicrobialpeptides that have the capability to be used therapeuticallyfor treatment of cancers.

Diffusion tensor imaging of the C1-C3 dorsal root ganglia and greater occipital nerve for cervicogenic headache

( Lang Wang ),( Jiang Shen ),( Sushant Das ),( Hanfeng Yang ) 대한통증학회 2020 The Korean Journal of Pain Vol.33 No.3

Background: Previous studies showed neurography and tractography of the greater occipital nerve (GON). The purpose of this study was determining diffusion tensor imaging (DTI) parameters of bilateral GONs and dorsal root ganglia (DRG) in unilateral cervicogenic headache as well as the grading value of DTI for severe headache. The correlation between DTI parameters and clinical characteristics was evaluated. Methods: The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values in bilateral GONs and cervical DRG (C2 and C3) were measured. Grading values for headache severity was calculated using a receiver operating characteristics curve. The correlation was analyzed with Pearson’s coefficient. Results: The FA values of the symptomatic side of GON and cervical DRG (C2 and C3) were significantly lower than that of the asymptomatic side (all the P < 0.001), while the ADC values were significantly higher (P = 0.003, P < 0.001, and P = 0.003, respectively). The FA value of 0.205 in C2 DRG was considered the grading parameter for headache severity with sensitivity of 0.743 and specificity of 0.999 (P < 0.001). A negative correlation and a positive correlation between the FA and ADC value of the GON and headache index (HI; r = -0.420, P = 0.037 and r = 0.531, P = 0.006, respectively) was found. Conclusions: DTI parameters in the symptomatic side of the C2 and C3 DRG and GON were significantly changed. The FA value of the C2 DRG can grade headache severity. DTI parameters of the GON significantly correlated with HI.

Hierarchical Model Predictive Control of Modular Multilevel Matrix Converter for Low Frequency AC Transmission

Lang Huang,Xu Yang,Bin Zhang,Liang Qiao,Hongchang Li,Mofan Tian 전력전자학회 2015 ICPE(ISPE)논문집 Vol.2015 No.6

The modular multilevel matrix converter (M3C) applied to a low frequency alternating current (LFAC) transmission system is investigated. Due to the complexity and tight coupling of the converter, a novel hierarchical model predictive control (MPC) scheme with a cascaded structure of power control, capacitor voltage averaging and balancing control for M3C is proposed. The terminal behavioral model of M3C is derived out and the fast separated space-vectors approximation method is realized. The proposed scheme clearly achieves the system-level multi-objective control without the empirical procedure of the weighting factor design and significantly reduces the computational cost. This is the first time to apply the MPC to a converter in a hierarchical structure. Simulation results of a 7-level M3C are provided to illustrate the system’s performance.

Preparation of activated carbon from waste cation exchange resin and its application in wastewater treatment

Yang Chane-Yuan,Kao Chao-Lang,Hung Pang-Yu 한국탄소학회 2022 Carbon Letters Vol.32 No.2

Recently, the circular economy aiming at elimination of waste and the continual use of resources has attracted a lot of attentions. In the circular system, the resource recovery uses the recycled wastes as the raw material to manufacture new valuable products. This work focuses on a low-cost process, in which an activated carbon (AC) adsorbent was prepared from waste cation exchange resin by calcination and HNO3 activation hydrothermal method. Surface structure and chemistry of AC were characterized by SEM, XRD, FTIR and Boehm titration. It was found that the acid treatment could increase the number of pores and the content of oxygen-containing functional groups on AC surface. In the adsorption experiment, Methylene blue (MB) was used to assess the adsorption capacity of AC. Experimental results showed that the highest efficiency of MB removal was achieved by AC with modification of 4M HNO3, showing the acidification effect on the adsorption capacity of AC. Adsorption isotherms of Langmuir and Freundlich were employed to fit the experimental data. It was shown that MB adsorption on AC is more consistent with Langmuir model that assumes a homogeneous adsorption. In the adsorption kinetic analysis, the adsorption was found to follow the pseudo-second-order model, indicating that adsorption of MB on acidified AC is dominated by chemical adsorption. The study revealed that the waste ion-exchange resin is a proper precursor of carbon adsorbent for MB dye. This low-cost method would specifically reduce the environmental cost of waste disposal.

Flexural Behavior of High Strength Concrete Filled Square Steel Tube with Inner CFRP Circular Tube

Zhijian Yang,Guochang Li,Yan Lang,Chen Fang 대한토목학회 2017 KSCE Journal of Civil Engineering Vol.21 No.7

This paper investigates the flexural behavior of high strength concrete filled square steel beam with inner CFRP (carbon fiberreinforced polymer) circular tube by the ABAQUS/Standard solver. In addition, eight specimens were fabricated and tested to investigate the pure flexural behavior. The test data was used to verify the Finite Element Analysis (FEA) modeling and good agreement was achieved in general. Furthermore, the influences of steel yielding strength, concrete strength, steel ratio and the thickness of CFRP on the flexural performance of the specimens were analyzed by FEA. According to the analysis of bending moment versus strain curves, the materials of CFRP, steel and concrete worked well together subjected to pure bending before the CFRP tube ruptured. The results presented in this paper show that these composite beams have a very ductile response because the concrete is confined by the CFRP tube and the steel tube. The beams’ flexural response, including the flexural stiffness and the ultimate load, can be substantially improved by the inner CFRP tube. The parametric studies provide information for the development of formulae to calculate the moment capacity. A comparison of experimental failure loads with the predicted failure loads in accordance with the formulae showed good agreement.

Dry hob with heat transfer enhancement based on field synergy and its temperature field distribution

Xiao Yang,Lang He,Peng Chen,Benjie Li,Yan-bin Du 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

Excessive heat accumulation is an essential factor in dry hob wear. Given this problem, this research is conducted on a dry hob with heat transfer enhancement by field synergy (FS-HTE dry hob). Firstly, through the combination of simulation and thermal image reconstruction, the heat accumulation behavior and thermal-induced wear mechanism are investigated for traditional dry hob. Then, using field synergy theory, a three-dimensional solid model is established for FS-HTE dry hob based on the structure of traditional dry hob. Finally, a process experiment by fluid-solid coupling simulation is executed to explore the temperature field distribution law of the FS-HTE dry hob as well as the temperature control mechanism. Results show that the minimum average temperature can be reached for the FS-HTE dry hob characterized by 0° synergy angle. It is also beneficial to suppress the thermal-induced wear benefiting from the characteristics of value and distribution law for the high-temperature region. The research demonstrates a potential method for the thermal-induced wear suppression of dry hob in green dry hobbing.

Reconstituted Fibril from Heterogenic Collagens-A New Method to Regulate Properties of Collagen Gels

Jian Yang,Haibo Wang,Lang He,Benmei Wei,Chengzhi Xu,Yuling Xu,Juntao Zhang,Sheng Li 한국고분자학회 2019 Macromolecular Research Vol.27 No.11

Heterotypic collagen fibril has long been found in the tissues of organisms, which plays an important role in the formation and function of complex structures of organisms. Inspiring by the phenomenon, scholars tried to incubate collagens from different sources into novel collagen materials in vitro, and the forming of heterogenic reconstituted collagen fibrils (RF) was often demonstrated by differential scanning calorimetry (DSC) and fluorescence quenching analysis. In this work, we used two type-I collagens from different species (bovine tendon and grasscarp fish skin) to coassemble in vitro, and verified the formation of RF from a new rheological perspective. In addition, we also investigated the assembly behavior, surface hydrophilicity and hydrophobicity, microscopic morphology and cell proliferation ability of the RF. The results showed that the assembly rate, surface properties, fibril size, viscoelastic properties of RF can be delicately regulated by the method of heterogenic collagen reconstitution. This study provides new experimental evidence for the reconstitution of heterogenic collagens, and also offers a new means for the regulation of collagen gel performance, which would help to expand the application range of collagen gel materials.

Chitin Enzymology Session / Deproteinization of shrimp and crab shell with the bacterial protease

(San Lang Wang),(Yi Shu Ou),(Jeng Gwo yang),(Sau Hwa Chio) 한국키틴키토산학회 1998 한국키틴키토산학회지 Vol.3 No.4