Leather and Footwear Journal

Volume 23, no 2

Contents
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SUPERCRITICAL FLUID EXTRACTED CHESTNUT TANNIN AS NATURAL BIOCIDE FOR SOAKING BEAMHOUSE PROCESS OF LEATHER PRODUCTION
- Pages 75-82
  Ersin ONEM*
  - Ege University, Faculty of Engineering, Department of Leather Engineering, 35100, Izmir, Turkiye, e-mail: ersin.onem@ege.edu.tr
  ABSTRACT. Microorganism activity during soaking beamhouse process of leather production is highly dangerous and should be kept under control. Some chemical components are used for this purpose to protect the hides/skins against microbial activities. Because of the banned and restricted substances due to the environmental and health risks in the recent times, natural active ingredients are considered for industrial production as sustainability. Moreover, supercritical fluid extraction as an environmentally friendly technology is applied to isolate biologically active extracts and supercritical extracted natural compounds are reported as potential antioxidant and antibacterial agent for several applications. In this study, supercritical fluid extracted chestnut tannin was used in soaking process of leather production and was determined as potential natural biocide with very good effect against microorganism activity in the process floats.
  
  KEY WORDS: leather, soaking, chestnut, biocide, bactericide, sustainability
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EFFECT OF CUSTOM-MADE ORTHOTIC INSOLES ON LOWER LIMB BIOMECHANICS IN CHILDREN WITH FLEXIBLE FLAT FEET
- Pages 83-92
  Yunqi TANG^{1, *}, Shizhe CHENG², Lingqiu ZOU^{1, 2}, Liying ZHOU¹, Peiyao LIANG¹, Hui REN¹, Xiaoli LIU³
  - ¹College of Art & Design, Shaanxi University of Science & Technology, Xi’an 710021, China
  - ²Jihua 3515 Leather and Leather Shoe Co., Ltd, Luo'he 462000, China
  - ³Xi 'an Children's Hospital, The Affiliated Children's Hospital of Xi 'an Jiaotong University, Xi 'an 710003, China
  ABSTRACT. This study aimed to investigate the effect of custom-made orthotic insoles on the lower limb biomechanics in children with flexible flat feet. A sample of 27 children (19 boys and eight girls) aged 7 to 13 years old with flexible flat feet participated in the study. Each custommade orthotic insole was individually designed based on the foot of each subject, using ethylene-vinyl acetate (EVA) material with medium density. The study was conducted using a gait analysis laboratory, and participants were required to walk randomly at a self-selected speed with one of three insole conditions (custom-made orthotic insole, flat insole, and barefoot). The data was processed using Visual 3D software and analyzed by SPSS software. The results showed that using custom-made orthotic insoles resulted in a significant reduction in the maximum ankle inversion angle and ankle inversion moment while increasing the knee adduction moment during the stance phase when compared to wearing either flat insoles or being barefoot (p<0.05). This study found that custom-made orthotic insoles significantly altered the biomechanical characteristics of the lower limbs of children with flexible flat feet, reducing the movement of the ankle joint in the frontal plane, thereby enhancing ankle joint stability, but may increase knee joint load.
  
  KEY WORDS: flexible flat foot; orthotic insole; ankle joint; knee joint
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EXPERT EXAMINATION OF LEATHER IN INTERNATIONAL TRADE: UKRAINIAN EXPERIENCE
- Pages 93-106
  Taras KARAVAYEV¹, Olena MOKROUSOVA^{1, *}, Kateryna YAZVINSKA², Maryna ZHALDAK¹, Valentyna TKACHUK³
  - ¹State University of Trade and Economics, Department of Commodity Science and Customs Affairs, 02156, 19 Kioto str., Kyiv, Ukraine, t.karavayev@knute.edu.ua, o.mokrousova@knute.edu.ua, m.zhaldak@knute.edu.ua
  - ²2State Customs Service of Ukraine, Specialized Laboratory for Expert Examination and Research, 04073, 8 Stepana Bandery avenue, Kyiv, Ukraine, katerina15.11.98@gmail.com
  - ³Lutsk National Technical University, Faculty of Customs Affairs, Materials and Technologies, 43018, 75 L’vivska str., Lutsk, Ukraine, v.tkachuk@lntu.edu.ua
  ABSTRACT. In the article the state of the market, volumes of export and import of leather are analyzed. The procedure of leather identification expert examination for customs purposes in international trade is showed. Identification expert examination of leather was carried out and its results were issued for customs purposes. The code of leather according to the Harmonized Commodity Description and Coding System (HS) and the Ukrainian Classification of Goods for Foreign Economic Activity (UСGFEA) is defined based on the results of identification expert examination.
  
  KEY WORDS: leather, genuine leather, export, import, identification expert examination, customs purpose, international trade, the HS, the UCGFEA
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APPLICATIONS OF ENZYMES AS ECOLOGIC ALTERNATIVES IN THE LEATHER INDUSTRY
- Pages 107-114
  Demetra SIMION^{1, *}, Carmen GAIDĂU¹, Gabriela PĂUN², Daniela BERECHET¹
  - ¹The National Research and Development Institute for Textiles and Leather (INCDTP) – Division: The Leather and Footwear Institute (ICPI), 93 Ion Minulescu st., postal code 031215, Bucharest, Romania
  - ²National Institute for Research-Development of Biological Sciences, 060031 Bucharest, Romania
  ABSTRACT. The aim of this paper is to study the applications of enzymes, as ecological alternatives in the leather industry. The research proposes to create ecologic leathers/furs with additional functions (non-toxic, with high-quality of soft, well-degreased surfaces) through the use of original enzyme-based biotechnologies, as new additives for leather/fur processing intended for everyday use. Another application of the enzymes studied in this paper is the development of a novel technology based on enzymes and membrane technique, for purifying wastewaters from the leather industry. We selected and analytically characterized lipases, proteases, and also new enzymes: lysozyme, tryptophan deaminase for use in leather industry. The goal was to obtain leathers/furs for everyday use, with high-performance characteristics, by processing them with enzymes – as new additives that have not been used so far in the leather industry as an alternative to the use of potentially polluting chemical materials. Complex and original technologies of ecological bioprocessing of leather/furs were used. The innovation consists in developing new biotechnologies for leather/fur with enzymatic additives in order to achieve ecologic leathers or fur articles. These biotechnologies provided advanced performances for surface quality: intense and bright colors, soft, welldegreased, and resistant to abrasion and water.
  
  KEY WORDS: original enzyme-based biotechnologies, ecologic leathers or fur articles with additional functions, technology based on enzymes and membrane technique for purifying wastewaters
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STUDIES REGARDING THE CYTOTOXICITY OF ANTIMICROBIAL GELS FORMULATED WITH NATURAL BIOPOLYMERS
- Pages 115-122
  Mohammed Shaymaa Omar MOHAMMED¹, Nicoleta RADU^{1, 2, *}, Rodica Roxana CONSTANTINESCU³, Petruța CORNEA¹, Magdalina URSU¹, Narcisa BĂBEANU¹
  - ¹University of Agronomic Sciences and Veterinary Medicine of Bucharest, 59 Marasti Blvd, Bucharest, e-mail: nicoleta.radu@biotehnologii.usamv.ro
  - ²National Institute of Chemistry and Petrochemistry R&D of Bucharest, 202 Splaiul Independentei street, District 6, Bucharest, e-mail: nicolbiotec@yahoo.com
  - ³INCDTP – Division: Leather and Footwear Research Institute (ICPI), Bucharest, 93 Ion Minulescu st., Sector 3, Bucharest, e-mail: rodica.roxana@yahoo.com
  ABSTRACT. Two antimicrobial gels, formulated with natural biopolymers (collagen and chitosan), limonene, and an imidazole derivative, were subjected to cytotoxicity tests. In these two compositions, the limonene content was 0.4% and 0.67%. The cytotoxicity tests were performed in vitro, using MTT methodology, and a standardized human normal cells line, HUVEC type. These cells were exposed to different levels of gel concentrations in the culture media. The final concentration of each gel type in culture media was situated between (0-0.125) μL/mL. The cell viability was determined after 24, 48 and 72h of exposure. The analyses showed that after 24h of exposure, the viability of the cells is greater than 91%, after 48h the viability is greater than 80%; after 72 h of exposure, the viability of the cells is greater than 74%. These values reveal that both selected gels exhibit no cytotoxicity for the normal cell line.
  
  KEY WORDS: antimicrobial gels, biopolymers, cytotoxicity
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INVESTIGATION OF THE EFFECTIVENESS OF PLANTAR PRESSURE REDISTRIBUTION OF CUSTOMIZED INSOLE STRUCTURE DESIGNED BASED ON PLANTAR STRUCTURE
- Pages 123-134
  Shunxun LI¹, Yichun SUN¹, Jin ZHOU^{1, *}, Bo XU^{1, 2}, Zhifeng YAO³, Wei LI³
  - ¹National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610065, P.R.China, zj_scu@scu.edu.cn
  - ²Xuzhou Qianbaidu Footwear Co., Ltd, 221200, P.R.China
  - ³Beijing Luxcreo, Inc., Beijing 100096, P.R.China, 1281157789@qq.com
  ABSTRACT. Although both fabricated insoles and customized insoles were designed with varied function components, current knowledge approved that customized insoles worked much better. However, how the customized insoles achieved a better performance in term of load re-distribution was still lacking quantitative assessment. The aim was to determine whether the customized insole structure based on a novel customization procedure proposed in this study performs better than the prefabricated insoles in terms of plantar pressure re-distribution efficiency. This study included ten healthy subjects, each wearing four types of insoles accordingly (control insoles; arch support insoles; orthotic insoles; customized insoles), and plantar pressure was collected in a walking state. The custom insoles are made by determining the subject’s plantar surface and key plantar points, then following the customization procedure to finish them. The plantar area was divided into eight zones and then a pressure transfer algorithm was used to gain insight into the plantar pressure. Compared to the control group insoles, the arch support of the customized insoles reduced pressure in the hallux region and transferred pressure from the M4-5 to the MH and LH regions, while the metatarsal pad enhanced the pressure transfer in the mid-foot, and the anterior-posterior height difference of the insole plays a role in pressure transfer. Furthermore, the customized insoles performed close to the professional orthotic insoles. Design strategy with accurate insole’s component location and reasonably plantar surface matching, our customized insole demonstrated advantages such as a better loading redistribution and significant pressure relieving on the forefoot.
  
  KEY WORDS: customized insole, prefabricated insole, pressure transfer, metatarsal pad, arch support
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EFFECT OF CUSTOM-DESIGNED INSOLE WITH ARCH AND METATARSAL SUPPORT ON ADJUSTMENT OF THE LOWER LIMB KINEMATICS
- Pages 135-150
  Yi-Chun SUN¹, Shun-Xun LI¹, Zhi-Feng YAO², Wei LI², Bo XU^{1, 3}, Jin ZHOU^{1, *}
  - ¹National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu 610000, China, sunyichun@stu.scu.edu.cn, lishunxun@stu.scu.edu.cn
  - ²Beijing Luxcreo, Inc., Beijing 100096, P.R.China, 1281157789@qq.com
  - ³Xuzhou Qianbaidu Footwear Co., Ltd, 221200, P.R.China
  ABSTRACT. Insole construction is considered to be related to stability in sports, and custom-made insoles with their scientifically tailored approach and effective construction are considered to be the main means of adjusting posture and reducing risk in sports. We have designed a non-100% full-fit design insole (CDI) with an arch support insole and metatarsal liner to determine whether this insole can be adapted to lower limb kinematics. Eleven healthy volunteers participated in this randomized crossover test in which a motion capture and 3D gait analysis system was used to measure the subjects’ lower limb kinematic data while exercising at different slopes and speeds wearing three different insoles: CDI, control Insole (CI) and arch support insoles (ASI). In addition, the experiments introduced the speed and slope factor, analyzed the extent to which speed slope affects joint angle using UNIANOVA, and compared the performance differences between the three insoles in different planes in pairs. The CDI inhibited ankle dorsiflexion and knee flexion in the sagittal plane; in the frontal plane, CDI reduced knee adduction and hip abduction angles. There was a statistically significant difference (p < 0.05) between the change in joint angle and the velocity slope. Slope*speed had a greater effect on the ankle and knee joints (%sig>30%). The results show that the CDI has better kinematic adjustability in the ankle and knee joints due to its superior insole design approach. Therefore, wearing the CDI may be an effective way of reducing risks in sports.
  
  KEY WORDS: customization, insole, sports injury, joint angle, gait kinematic features
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