A Hybrid Color Space for Skin Detection Using Genetic Algorithm Heuristic Search and Principal Component Analysis Technique

Color is one of the most prominent features of an image and used in many skin and face detection applications. Color space transformation is widely used by researchers to improve face and skin detection performance. Despite the substantial research efforts in this area, choosing a proper color space in terms of skin and face classification performance which can address issues like illumination variations, various camera characteristics and diversity in skin color tones has remained an open issue. This research proposes a new three-dimensional hybrid color space termed SKN by employing the Genetic Algorithm heuristic and Principal Component Analysis to find the optimal representation of human skin color in over seventeen existing color spaces. Genetic Algorithm heuristic is used to find the optimal color component combination setup in terms of skin detection accuracy while the Principal Component Analysis projects the optimal Genetic Algorithm solution to a less complex dimension. Pixel wise skin detection was used to evaluate the performance of the proposed color space. We have employed four classifiers including Random Forest, Naïve Bayes, Support Vector Machine and Multilayer Perceptron in order to generate the human skin color predictive model. The proposed color space was compared to some existing color spaces and shows superior results in terms of pixel-wise skin detection accuracy. Experimental results show that by using Random Forest classifier, the proposed SKN color space obtained an average F-score and True Positive Rate of 0.953 and False Positive Rate of 0.0482 which outperformed the existing color spaces in terms of pixel wise skin detection accuracy. The results also indicate that among the classifiers used in this study, Random Forest is the most suitable classifier for pixel wise skin detection applications.     

Rosin Surfactant QRMAE Can Be Utilized as an Amorphous Aggregate Inducer: A Case Study of Mammalian Serum Albumin

Quaternary amine of diethylaminoethyl rosin ester (QRMAE), chemically synthesized biocompatible rosin based cationic surfactant, has various biological applications including its use as a food product additive. In this study, we examined the amorphous aggregation behavior of mammalian serum albumins at pH 7.5, i.e., two units above their isoelectric points (pI ~5.5), and the roles played by positive charge and hydrophobicity of exogenously added rosin surfactant QRMAE. The study was carried out on five mammalian serum albumins, using various spectroscopic methods, dye binding assay, circular dichroism and electron microscopy. The thermodynamics of the binding of mammalian serum albumins to cationic rosin modified surfactant were established using isothermal titration calorimetry (ITC). It was observed that a suitable molar ratio of protein to QRMAE surfactant enthusiastically induces amorphous aggregate formation at a pH above two units of pI. Rosin surfactant QRMAE-albumins interactions revealed a unique interplay between the initial electrostatic and the subsequent hydrophobic interactions that play an important role towards the formation of hydrophobic interactions-driven amorphous aggregate. Amorphous aggregation of proteins is associated with varying diseases, from the formation of protein wine haze to the expansion of the eye lenses in cataract, during the expression and purification of recombinant proteins. This study can be used for the design of novel biomolecules or drugs with the ability to neutralize factor(s) responsible for the aggregate formation, in addition to various other industrial applications.     

Problem-Solving Skills Appraisal Mediates Hardiness and Suicidal Ideation among Malaysian Undergraduate Students

Objectives

Recent evidence suggests that suicidal ideation is increased among university students, it is essential to increase our knowledge concerning the etiology of suicidal ideation among university students. This study was conducted to examine the relationships between problem-solving skills appraisal, hardiness, and suicidal ideation among university students. In addition, this study was conducted to examine problem-solving skills appraisal (including the three components of problem-solving confidence, approach-avoidance style, and personal control of emotion) as a potential mediator between hardiness and suicidal ideation.

Methods

The participants consisted of 500 undergraduate students from Malaysian public universities.

Results

Structural Equation Modelling (SEM) estimated that undergraduate students with lower hardiness, poor problem-solving confidence, external personal control of emotion, and avoiding style was associated with higher suicidal ideation. Problem-solving skills appraisal (including the three components of problem-solving confidence, approach-avoidance style, and personal control of emotion) partially mediated the relationship between hardiness and suicidal ideation.

Conclusion

These findings underline the importance of studying mediating processes that explain how hardiness affects suicidal ideation.     

Degradation and Mineralization of Phenol Compounds with Goethite Catalyst and Mineralization Prediction Using Artificial Intelligence

The efficiency of phenol degradation via Fenton reaction using mixture of heterogeneous goethite catalyst with homogeneous ferrous ion was analyzed as a function of three independent variables, initial concentration of phenol (60 to 100 mg /L), weight ratio of initial concentration of phenol to that of H₂O₂ (1: 6 to 1: 14) and, weight ratio of initial concentration of goethite catalyst to that of H₂O₂ (1: 0.3 to 1: 0.7). More than 90 % of phenol removal and more than 40% of TOC removal were achieved within 60 minutes of reaction. Two separate models were developed using artificial neural networks to predict degradation percentage by a combination of Fe³⁺ and Fe²⁺ catalyst. Five operational parameters were employed as inputs while phenol degradation and TOC removal were considered as outputs of the developed models. Satisfactory agreement was observed between testing data and the predicted values (R² _Phenol = 0.9214 and R²TOC= 0.9082).     

Antimicrobial Activity of Novel Synthetic Peptides Derived from Indolicidin and Ranalexin against Streptococcus pneumoniae

Antimicrobial peptides (AMPs) represent promising alternatives to conventional antibiotics in order to defeat multidrug-resistant bacteria such as Streptococcus pneumoniae. In this study, thirteen antimicrobial peptides were designed based on two natural peptides indolicidin and ranalexin. Our results revealed that four hybrid peptides RN7-IN10, RN7-IN9, RN7-IN8, and RN7-IN6 possess potent antibacterial activity against 30 pneumococcal clinical isolates (MIC 7.81-15.62µg/ml). These four hybrid peptides also showed broad spectrum antibacterial activity (7.81µg/ml) against S. aureus, methicillin resistant S. aureus (MRSA), and E. coli. Furthermore, the time killing assay results showed that the hybrid peptides were able to eliminate S. pneumoniae within less than one hour which is faster than the standard drugs erythromycin and ceftriaxone. The cytotoxic effects of peptides were tested against human erythrocytes, WRL-68 normal liver cell line, and NL-20 normal lung cell line. The results revealed that none of the thirteen peptides have cytotoxic or hemolytic effects at their MIC values. The in silico molecular docking study was carried out to investigate the binding properties of peptides with three pneumococcal virulent targets by Autodock Vina. RN7IN6 showed a strong affinity to target proteins; autolysin, pneumolysin, and pneumococcal surface protein A (PspA) based on rigid docking studies. Our results suggest that the hybrid peptides could be suitable candidates for antibacterial drug development.     

Imaging techniques for the detection of stored product pests

Stored grains are subject to deterioration and losses through various factors, but mainly insects and fungi. Various techniques are employed to detect stored product pests; however, there is an urgent need for an industrial-scale on-line detection technique. Near-infrared hyperspectroscopic imaging and soft X-rays have shown the potential for real-time application. These techniques are particularly effective for detecting internal infestations of stored grains. The digital images of the scanned objects are analyzed for various spectral and image features using statistical techniques such as complex multivariate tools. Classification accuracies as high as 80–100 % have been achieved for various pest and grain combinations. Dual-energy X-rays have been shown to detect the concealed eggs of stored product insect pests. The main threats to stored cereals come from Aspergillus spp., Penicillium spp., and Fusarium spp., which may produce mycotoxins. These imaging techniques have shown good results in the detection of fungal infections of stored grain.     

Preliminary studies on cryopreservation of snakehead (Channa striata) embryos

This paper reports the findings of the ongoing studies on cryopreservation of the snakehead, Channa striata embryos. The specific objective of this study was to collect data on the sensitivity of C. striata embryo hatching rate to low temperatures at two different developmental stages in the presence of four different cryoprotectants. Embryos at morula and heartbeat stages were selected and incubated in 1 M dimethyl sulfoxide (Me₂SO), 1 M ethylene glycol (EG), 1 M methanol (MeOH) and 0.1 M sucrose solutions at different temperatures for a period of time. Embryos were kept at 24 °C (control), 15 °C, 4 °C and −2 °C for 5 min, 1 h and 3 h. Following these treatments, the embryos were then transferred into a 24 °C water bath until hatch to evaluate the hatching rate. The results showed that there was a significant decrease of hatching rate in both developmental stages following exposure to 4 °C and −2 °C at 1 h and 3 h exposure in each treatment. Heartbeat stage was more tolerant against chilling at −2 °C for 3 h exposure in Me₂SO followed by MeOH, sucrose and EG. Further studies will be conducted to find the best method to preserve embryos for long term storage.     

More stable structure of wheat germ lipase at low pH than its native state

Wheat germ lipase is a cereal lipase which is a monomeric protein. In the present study we sought to structurally characterize this protein along with equilibrium unfolding in solution. Conformational changes occurring in the protein with varying pH, were monitored by circular dichroism (CD) spectroscopy, fluorescence emission spectroscopy, binding of hydrophobic dye, 1-anilino 8-naphthalenesulfonic acid (ANS) and dynamic light scattering (DLS). Our study showed that acid denaturation of lipase lead to characterization of multiple monomeric intermediates. Native protein at pH 7.0 showed far-UV spectrum indicating mixed structure with both alpha and beta-type of characteristics. Activity of lipase was found to fall on either sides of pH 7.0–8.0. Acid-unfolded state was characterized at pH 4.0 with residual secondary structure, disrupted tertiary spectrum and red-shifted fluorescence spectrum with decreased intensity. Further decrease in pH lead to formation of secondary structure and acid-induced molten globule state was found to be stabilized at pH 1.4, with exposed tryptophan residues and hydrophobic patches. Notably, interesting finding of this study was characterization of acid-induced state at pH 0.8 with higher secondary structure content than native lipase, regain in tertiary spectrum and induction of compact conformation. Although enzymatically inactive, acid-induced state at pH 0.8 was found to be structurally more stable than native lipase, as shown by chemical and thermal denaturation profiles.     

Ligand binding strategies of human serum albumin: How can the cargo be utilized?

Human serum albumin (HSA), being the most abundant carrier protein in blood and a modern day clinical tool for drug delivery, attracts high attention among biologists. Hence, its unfolding/refolding strategies and exogenous/endogenous ligand binding preference are of immense use in therapeutics and clinical biochemistry. Among its fellow proteins albumin is known to carry almost every small molecule. Thus, it is a potential contender for being a molecular cargo/or nanovehicle for clinical, biophysical and industrial purposes. Nonetheless, its structure and function are largely regulated by various chemical and physical factors to accommodate HSA to its functional purpose. This multifunctional protein also possesses enzymatic properties which may be used to convert prodrugs to active therapeutics. This review aims to highlight current overview on the binding strategies of protein to various ligands that may be expected to lead to significant clinical applications. Chirality, 2010. © 2009 Wiley‐Liss, Inc.     

Firefly distribution and abundance on mangrove vegetation assemblages in Sepetang estuary,Peninsular Malaysia

Pteroptyx fireflies are commonly reported to congregate in large numbers in mangroves. Not much is known about the relationships between firefly distribution and abundance with specific mangrove vegetation assemblages. We conducted a study to investigate the vegetation assemblages that structure the distribution and abundance of Pteroptyx tener in Peninsular Malaysia. The distribution and abundance of fireflies were assessed along an 8 km stretch of mangroves in Sepetang estuary using visual assessment. Statistical analysis was carried out to test the correlation between length of display section and percentage cover of P. tener colonies and the relationship between percentage cover of fireflies with different vegetation assemblages. Five distinct vegetation assemblages were identified comprising different combination of four mangrove species. It was found that shorter display sections had higher percentage cover of P. tener colonies. In addition, vegetation assemblage which consisting of mainly Sonneratia caseolaris and Nypa fruticans was the most preferred type. The results of this study point to the necessity to consider not only a single mangrove species but the entire vegetation assemblage for firefly conservation.