Leather and Footwear Journal

Volume 16, no 2

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Features of Plantar Pressure Distribution of Children with Spastic Diplegia
- Pages 95-104
  Weijuan ZHANG¹, Bo XU², Jin ZHOU², Baozhen CHENG¹*
  - ¹Tianjin University of Science & Technology, Tianjin, China, zhang_weijuan@163.com
  - ²National Engineering Laboratory for Clean Technology of Leather Manufacture, Sichuan University, Chengdu, P. R. China
  ABSTRACT. The aim of this study was to investigate the features of plantar pressure distribution of children with spastic diplegia. Totally, 18 spastic diplegia children (SDCP) and 36 typical developed counterparts (TD) with matching age, height and weight were recruited. Their plantar pressure distributions were measured and analyzed. Three-masks model was first used to divide the foot regions: forefoot, midfoot and hindfoot, then the relative contact time (CTrel) (%), peak pressure (PP) (N/cm²), relative pressure time integral (PTIrel) (%) and relative contact area (CA) (%) were calculated. Our outcomes show that pressure variables were significantly higher than those of TD in most regions, with the exception of PP; further, a prolonged first PP curve was obtained for SDCP in the double support phase. At last, all data of SDCP were moderate for the most of variables and regions. Thereby, features of SDCP children are shown below: no bimodal pressure curve was obtained and they usually performed with valgus deformities, so that midfoot was used as a major loading area.
  
  KEY WORDS: plantar pressure distribution, spastic diplegia, cerebral palsy, typical developed children
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Comparative Analysis of Dynamic Plantar Pressure Distribution on Different Areas of the Foot
- Pages 105-112
  Mariana COSTEA, Aura MIHAI*
  - Gheorghe Asachi Technical University of Iasi, 67 Dimitrie Mangeron Blvd., Iasi, Romania, amihai@tex.tuiasi.ro
  ABSTRACT. The plantar distribution between the foot and the contact surface provides valuable information about the foot's structure and functions. The plantar footprints were taken from 60 young women, aged between 20-30 and their foot typology was established by the authors in a previous study. The average values of the plantar pressures recorded on ten foot segments, in case of the four groups: normal foot, high arched foot, flat foot and Hallux-Valgus foot were analyzed in the present study. By comparing the pressures for the four identified groups, it was demonstrated that there are no significant differences between subjects, the maximum values being registered on the third metatarsal head bone, followed by the second metatarsal head bone and the heel. The findings of a Pearson correlation analysis demonstrate that some pressure areas are directly proportional to others (like for example toe areas with first, second, fourth metatarsal head bones and median area of the foot) and other pressure areas are indirectly proportional to others (like for example lateral heel, with second to fifth toe). An important result of the performed analysis is the negative correlation between toe area and the third and fifth metatarsals head bones. Therefore, when creating the footwear bottom components, the designer should use different materials and structures and design in order to redistribute the plantar pressures according to areas of the foot.
  
  KEY WORDS: plantar footprint, gait, pressure areas, footwear
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Phyto-Based Preservation of Raw Skins for Salinity Reduction in Tannery Wastewater
- Pages 113-132
  Marudhamuthu VINODHKUMAR¹*, Velappan BRINDHA², James KANAGARAJ², Alagumuthu TAMILSELVI¹, Sayeed SADULLA³
  - ¹Centre for Human and Organizational Resources Development (CHORD), CSIR-CLRI, Chennai, India, vinodh14579@gmail.com
  - ²Leather Process Technology Division, CSIR-CLRI
  - ³Indian Leather Products Association, Chennai, India
  ABSTRACT. Leather industry is one of the top polluting industries albeit producing precious commodities for human use. Curing of raw skins and hides with salt is one chief deterrent increasing the Total Dissolved Solids (TDS) of water bodies and fertile lands. In this present investigation, an attempt has been made to reduce the salt used for preservation by substituting with plant extracts. Plants like Cassia fistula Linn. (Cassia), family Caesalpiniaceae and Psidium guajava L, family Myrtaceae display brilliant antimicrobial qualities. Experimental skin (goat) samples were treated with5% Salt + 5% Cassia paste, 10% Salt + 10% Cassia paste, 15% Salt + 15% Cassia paste, 5% salt + 5% Guava paste, 10% salt + 10% Guava paste, 15% salt + 15% Guava paste and 40% salt according to the skin weights respectively. The experimental skins were preserved for 21 days and were observed for hair slip, smell and putrefaction. Estimation of protein, hydroxyproline and moisture content and microbial load were tested on the 1st, 2nd, 3rd, 7th, 14th and 21st day. On the 21st day the skins were processed into leather and their physical properties were examined and found comparable to the conventionally cured skins. Hence, this cleaner curing method helps in reducing the TDS in the effluent, thus controlling pollution caused by tanneries through salt.
  
  KEY WORDS: phyto-based preservation, Cassia fistula, Psidium guajava, wastewater, salinity reduction
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The Electric Active Starch Flocculation of Protein and its Degradation Products in Leather Effluents
- Pages 133-146
  Rui LI^1,2, Yuzeng WANG^1,2, Rui DAI^1,2, Zhihua SHAN^1,2*
  - ¹The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu, 610065, China, 549671254@qq.com
  - ²College of Light Industry, Textile and Food Engineering, Chengdu, 610065, China
  ABSTRACT. There is a large amount of protein or its degradation products in leather effluents, which are difficult to deal with, such as NH₃-N and SS (suspended solids), etc., so it is significant to remove all the protein residues in effluents and reduce the content of pollutants. This experiment simulates the main effluent compositions which contained protein and its degradation products, and then handled with electrochemical assisted starch flocculate to reduce the content of protein residues in effluents, whilst decreasing the value of COD and BOD. Based on experiment results and the DPS statistical software analysis, the optimal conditions to remove the protein residues would be obtained, among 2.5 g/L protein degradation products, 5 g/L starch content, 5 g/L chloride ion concentration and 20 min electrolysis time, respectively, under which the best removal rate is 36.17%. The flocculation was analyzed by Fourier transform infrared spectroscopy (FTIR), nanoparticle size potential analyzer (Zeta analyzer) and atomic force microscopy (AFM), and then presumed the removal mechanism of the protein residues in effluents.
  
  KEY WORDS: electrochemistry; starch; flocculation; protein residue removal rate; removal mechanism
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Determination of Hydroxyproline in Collagen Biomaterials for Medical Use and Validation of Method
- Pages 147-162
  Gabriela MACOVESCU*, Ciprian CHELARU, Mădălina Georgiana ALBU KAYA, Luminița ALBU
  - INCDTP - Division: Leather and Footwear Research Institute, 93 Ion Minulescu, 031215, Bucharest, Romania, icpi@icpi.ro
  ABSTRACT. The paper presents a method for determining hydroxyproline in collagen biomaterials for medical use produced in The Collagen Department of INCDTP - Division ICPI and its validation. The method has two stages: the first one consists in hydrolysis of proteins in the sample of protein product to the form of amino acids, among which hydroxyproline. The second stage refers to selective highlighting of hydroxyproline using a specific colour reaction and quantitative assessment against a reference standard with known concentration. The method was validated to establish performance parameter and to check compliance with the set goal.
  
  KEY WORDS: biomaterials, hydroxyproline, validation of method, collagen
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