Urea and thermal denaturations of bovine serum albumin (BSA) were studied in the absence and the presence of honey or simulated honey sugar cocktail (SHSC) using far-UV CD and ANS fluorescence spectroscopy. Presence of 20% (w/v) honey or SHSC in the incubation mixture shifted the urea transition curve towards higher urea concentrations, being higher in the presence of honey and transformed the two-step, three-state transition into a single-step, two-state transition. A comparison of the far-UV CD and the ANS fluorescence spectra of 4.6 M urea-denatured BSA (U-BSA) in the absence and the presence of 20% (w/v) honey or SHSC suggested greater stabilizing potential of honey than SHSC, as U-BSA maintained native like conformation in the presence of 20% (w/v) honey. Furthermore, thermal transition curves of BSA were also shifted towards higher temperature range in the presence of 20% (w/v) SHSC and honey, showing greater shift in the presence of honey. The far-UV CD spectra of the heat-denatured BSA also showed greater stabilization in the presence of honey. Taken together all these results suggested greater protein stabilizing potential of honey than SHSC against chemical and thermal denaturations of BSA.
The aim of the present research was to evaluate the application, stability and suitability of ω3 polyunsaturated fatty acids (PUFAs) incorporated nanoliposomes in food enrichment. Nanoliposomal ω3 PUFAs was prepared by Mozafari method, and their application in bread and milk was compared with unencapsulated (fish oil) and microencapsulated ω3 PUFAs. Sensory evaluation was conducted to determine the perceptible sensory difference/similarity between control, unencapsulated, microencapsulated, and nanoliposomal ω3 PUFAs enriched foods. Results showed no significant (p=0.11) detectable difference between control and nanoliposomal ω3 PUFAs enriched samples while, samples enriched with unencapsulated or microencapsulated ω3 PUFAs showed significant (p=0.02) fishy flavor. Moreover, significantly (p<0.01) higher ω3 PUFAs % recovery and lower peroxide and anisidine values were observed in nanoliposomal ω3 PUFAs enriched samples in comparison with other samples. In conclusion, an effective and reproducible method for application of ω3 PUFAs in the food system was developed.
Here, we report that long-term stable and efficient organic solar cells (OSCs) can be obtained through the following strategies: i) combination of rapid-drying blade-coating deposition with an appropriate thermal annealing treatment to obtain an optimized morphology of the active layer; ii) insertion of interfacial layers to optimize the interfacial properties. The resulting devices based on poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b;4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)-3-fluorothieno[3,4-b]thiophene-2-carboxylate-2,6-diyl)] (PBDTTT-EFT):[6,6]-phenyl C71 butyric acid methyl ester (PC71 BM) blend as the active layer exhibits a power conversion efficiency (PCE) up to 9.57 %, which represents the highest efficiency ever reported for blade-coated OSCs. Importantly, the conventional structure devices based on poly(3-hexylthiophene) (P3HT):phenyl-C61 -butyric acid methyl ester (PCBM) blend can retain approximately 65 % of their initial PCE for almost 2 years under operating conditions, which is the best result ever reported for long-term stable OSCs under operational conditions. More encouragingly, long-term stable large-area OSCs (active area=216 cm2 ) based on P3HT:PCBM blend are also demonstrated. Our findings represent an important step toward the development of large-area OSCs with high performance and long-term stability.
Harvesting microalgae from medium is a major challenge due to their small size and low concentrations. In an attempt to find a cost-effective and eco-friendly harvesting technique, mung bean (Vigna radiata) protein extract (MBPE) was used for flocculation of Nannochloropsis sp. The effects of parameters such as pH, flocculant dose, algae concentration, and mixing time were used to study the flocculation efficiency (FE) of MBPE. Optimum parameters of MBPE dosage of 20 mL L(-1) and a mixing rate of 300 rpm for 6 min achieved a FE of >92% after 2 h of settling time. MBPE-aggregated microlga flocs were characterized by microscopy. Zeta potential values decreased with increasing flocculant dose, and the values obtained were -6.93 ± 0.60, -5.36 ± 0.64, and -4.44 ± 0.22 for doses of 10, 20, and 30 mL L(-1), respectively. In conclusion, MBPE flocculants used in this study are safe, nontoxic, and pollution free, so they could be used for an effective, convenient, and rapid harvesting of microalgae in an eco-friendly approach. These methods are sustainable and could be applied in industrial scale for aquaculture nutrition.
In this study, microcrystalline cellulose (MCC) was extracted from roselle fiber through acid hydrolysis treatment and its properties were compared with those of commercially available MCC. The physicochemical and morphological characteristics, elemental composition, size distribution, crystallinity and thermal properties of the obtained MCC were analyzed in this work. Fourier transform infrared spectroscopy (FTIR) analysis provided clear evidence that the characteristic peak of lignin was absent in the spectrum of the MCC prepared from roselle fiber. Rough surface and slight aggregation of MCC were observed by scanning electron microscopy (SEM). Energy dispersive X-ray (EDX) analysis showed that pure MCC with small quantities of residues and impurities was obtained, with a similar elemental composition to that of commercial MCC. A mean diameter of approximately 44.28μm was measured for MCC by using a particle size analyzer (PSA). X-ray diffraction (XRD) showed the crystallinity increased from 63% in roselle pulp to 78% in roselle MCC, the latter having a slightly higher crystallinity than that of commercial MCC (74%). TGA and DSC results indicated that the roselle MCC had better thermal stability than the roselle pulp, whereas it had poorer thermal stability in comparison with commercial MCC. Thus, the isolated MCC from roselle fibers will be going to use as reinforcing element in green composites and may be a precursor for future roselle derived nanocellulose, and thus a promising subject in nanocomposite research.
A new era of metal-based drugs started in the 1960s, heralded by the discovery of potent platinum-based complexes, commencing with cisplatin [(H₃N)₂PtCl₂], which are effective anti-cancer chemotherapeutic drugs. While clinical applications of gold-based drugs largely relate to the treatment of rheumatoid arthritis, attention has turned to the investigation of the efficacy of gold(I) and gold(III) compounds for anti-cancer applications. This review article provides an account of the latest research conducted during the last decade or so on the development of gold compounds and their potential activities against several cancers as well as a summary of possible mechanisms of action/biological targets. The promising activities and increasing knowledge of gold-based drug metabolism ensures that continued efforts will be made to develop gold-based anti-cancer agents.
Thermodynamic and kinetic parameters of catalytic pyrolysis of rice hull (RH) pyrolysis using two different types of renewable catalysts namely natural limestone (LS) and eggshells (ES) using thermogravimetric analysis (TG) approach at different heating rates of 10-100 K min-1 in temperature range of 323-1173 K are investigated. Catalytic pyrolysis mechanism of both catalysts had shown significant effect on the degradation of RH. Model free kinetic of iso-conversional method (Flynn-Wall-Ozawa) and multi-step reaction model (Distributed Activation Energy Model) were employed into present study. The average activation energy was found in the range of 175.4-177.7 kJ mol-1 (RH), 123.3-132.5 kJ mol-1 (RH-LS), and 96.1-100.4 kJ mol-1 (RH-ES) respectively. The syngas composition had increased from 60.05 wt% to 63.1 wt% (RH-LS) and 63.4 wt% (RH-ES). However, the CO2 content had decreased from 24.1 wt% (RH) to 20.8 wt% (RH-LS) and 19.9 wt% (RH-ES).
Three new bisindole alkaloids, bisleuconothines B-D (1-3), were isolated from the bark of Leuconotis griffithii. Their structures were elucidated by 1D and 2D NMR spectroscopy and DFT calculations. Bisleuconothine B (1) is the first monoterpene indole alkaloid dimer featuring bridges between both C-16-C-10' and C-2-O-C-9'. All compounds were deemed noncytotoxic (IC50 > 10 μM) when tested against A549 human lung adenocarcinoma cells.
For decades, water treatment plants in Malaysia have widely employed aluminium-based coagulant for the removal of colloidal particles in surface water. This generates huge amount of by-product, known as sludge that is either reused for land applications or disposed to landfills. As sludge contains high concentration of aluminium, both can pose severe environmental issues. Therefore, this study explored the potential to recover aluminium from water treatment sludge using acid leaching process. The evaluation of aluminium recovery efficiency was conducted in two phases. The first phase used the one factor at a time (OFAT) approach to study the effects of acid concentration, solid to liquid ratio, temperature and heating time. Meanwhile, second phase emphasized on the optimization of aluminium recovery using Response Surface Methodology (RSM). OFAT results indicated that aluminium recovery increased with the rising temperature and heating time. Acid concentration and solid to liquid ratio, however, showed an initial increment followed by reduction of recovery with increasing concentration and ratio. Due to the solidification of sludge when acid concentration exceeded 4 M, this variable was fixed in the optimization study. RSM predicted that aluminium recovery can achieve 70.3% at optimal values of 4 M, 20.9%, 90 °C and 4.4 h of acid concentration, solid to liquid ratio, temperature and heating time, respectively. Experimental validation demonstrated a recovery of 68.8 ± 0.3%. The small discrepancy of 2.2 ± 0.4% between predicted and validated recovery suggests that RSM was a suitable tool in optimizing aluminium recovery conditions for water treatment sludge.
In this study, a simple sugaring-out supported by liquid biphasic flotation technique combined with ultrasonication was introduced for the extraction of proteins from microalgae. Sugaring-out as a phase separation method is novel and has been used in the extraction of metal ions, biomolecules and drugs. But, its functioning in protein separation from microalgae is still unknown. In this work, the feasibility of sugaring-out coupled with ultrasound for the extraction of protein was investigated. Primary studies were carried out to examine the effect of sonication on the microalgae cell as well as the separation efficiency of the integrated method. Effect of various operating parameters such as the concentration of microalgae biomass, the location of sonication probe, sonication time, ultrasonic pulse mode (includes varying ON and OFF duration of sonication), concentration of glucose, types of sugar, concentration of acetonitrile and the flow rate in the flotation system for achieving a higher separation efficiency and yield of protein were assessed. Besides, a large-scale study of the integration method was conducted to verify the consistency of the followed technique. A maximum efficiency (86.38%) and yield (93.33%) were attained at the following optimized conditions: 0.6% biomass concentration, 200 g/L of glucose concentration, 100% acetonitrile concentration with 5 min of 5 s ON/10 s OFF pulse mode and at a flow rate of 100 cc/min. The results obtained for large scale were 85.25% and 92.24% for efficiency and yield respectively. The proposed liquid biphasic flotation assisted with ultrasound for protein separation employing sugaring-out demonstrates a high production and separation efficiency and is a cost-effective solution. More importantly, this method provides the possibility of extending its application for the extraction of other important biomolecules.
A novel way to fully utilize rambutan fruit and seed is to ferment peeled fruits followed by drying and roasting, and use the seeds to produce seed powder similar to that of cocoa powder. Hence, the objective of this study was to optimize the roasting time and temperature of rambutan fruit post-fermentation and drying, and to produce a cocoa-like powder product from the seeds. Parameters monitored during roasting were colour and total phenolic content, while seed powder obtained using optimized roasting conditions was analyzed for its physicochemical properties and toxicity. The latter was examined using the brine shrimp lethality assay. Results showed that the roasted seed powder possessed colour and key volatile compounds similar to that of cocoa powder. Besides, the brine shrimp lethality assay indicated that the roasted seed powder was non-toxic. Thus, the fruit, including its seed could be fully utilized and subsequently, wastage could be reduced.
Two azide-terminated oligoethylene oxide spacered glycolipids have been synthesized, and their assembly behavior has been studied in comparison to the corresponding base surfactants. The results suggest potential of the Guerbet lactoside-based compound for targeted drug delivery, while a coiling of the ethylene oxide linker disfavors the application of the glucoside.
Calloselasma rhodostoma (CR) and Ophiophagus hannah (OH) are two medically important snakes found in Malaysia. While some studies have described the biological properties of these venoms, feeding and environmental conditions also influence the concentration and distribution of snake venom toxins, resulting in variations in venom composition. Therefore, a combined proteomic approach using shotgun and gel filtration chromatography, analyzed by tandem mass spectrometry, was used to examine the composition of venoms from these Malaysian snakes. The analysis revealed 114 proteins (15 toxin families) and 176 proteins (20 toxin families) in Malaysian Calloselasma rhodostoma and Ophiophagus hannah species, respectively. Flavin monoamine oxidase, phospholipase A₂, phosphodiesterase, snake venom metalloproteinase, and serine protease toxin families were identified in both venoms. Aminopeptidase, glutaminyl-peptide cyclotransferase along with ankyrin repeats were identified for the first time in CR venom, and insulin, c-type lectins/snaclecs, hepatocyte growth factor, and macrophage colony-stimulating factor together with tumor necrosis factor were identified in OH venom for the first time. Our combined proteomic approach has identified a comprehensive arsenal of toxins in CR and OH venoms. These data may be utilized for improved antivenom production, understanding pathological effects of envenoming, and the discovery of biologically active peptides with medical and/or biotechnological value.
The interaction between mefloquine (MEF), the antimalarial drug, and human serum albumin (HSA), the main carrier protein in blood circulation, was explored using fluorescence, absorption, and circular dichroism spectroscopic techniques. Quenching of HSA fluorescence with MEF was characterized as static quenching and thus confirmed the complex formation between MEF and HSA. Association constant values for MEF-HSA interaction were found to fall within the range of 3.79-5.73 × 104 M-1 at various temperatures (288, 298, and 308 K), which revealed moderate binding affinity. Hydrogen bonds and hydrophobic interactions were predicted to connect MEF and HSA together in the MEF-HSA complex, as deduced from the thermodynamic data (ΔS = +133.52 J mol-1 K-1 and ΔH = +13.09 kJ mol-1 ) of the binding reaction and molecular docking analysis. Three-dimensional fluorescence spectral analysis pointed out alterations in the microenvironment around aromatic amino acid (tryptophan and tyrosine) residues of HSA consequent to the addition of MEF. Circular dichroic spectra of HSA in the wavelength ranges of 200-250 and 250-300 nm hinted smaller changes in the protein's secondary and tertiary structures, respectively, induced by MEF binding. Noncovalent conjugation of MEF to HSA bettered protein thermostability. Site marker competitive drug displacement results suggested HSA Sudlow's site I as the MEF binding site, which was also supported by molecular docking analysis.
Graphene is a 2-dimensional nanomaterial with an atomic thickness has attracted a strong scientific interest owing to their remarkable optical, electronic, thermal, mechanical and electrochemical properties. Graphene-based materials particularly graphene oxide and reduced graphene oxide are widely utilized in various applications ranging from food industry, environmental monitoring and biomedical fields as well as in the development of various types of biosensing devices. The richness in oxygen functional groups in the materials serves as a catalysis for the development of biosensors/electrochemical biosensors which promotes for an attachment of biological recognition elements, surface functionalization and compatible with micro- and nano- bio-environment. In this review, the graphene-based materials application in electrochemical biosensors based on recent advancement (e.g; the surface modification and analytical performances) and the utilization of such biosensors to monitor the noncommunicable diseases are presented. The detection performances of the graphene-based electrochemical biosensors are in the range of ng/mL and have reached up to fg/mL in detecting the targets of NCDs with higher selectivity, sensitivity and stability with good reproducibility attributes. We have discussed the advances while addressing the very specific biomarkers for the NCDs detection. Challenges and possible future research directions for the NCDs detection based on graphene nanocomposite with other 2D nanomaterials are outlined.
The food and health applications of bioactive peptides have grown remarkably in the past few decades. Current elucidations have shown that bioactive peptides have unique structural arrangement of amino acids, conferring distinct functionalities, and molecular affinity characteristics. However, whereas interest in the biological potency of bioactive peptides has grown, cost-effective techniques for monitoring the structural changes in these peptides and how these changes affect the biological properties have not grown at the same rate. Due to the high binding affinity of aptamers for other biomolecules, they have a huge potential for use in tracking the structural, conformational, and compositional changes in bioactive peptides. This review provides an overview of bioactive peptides and their essential structure-activity relationship. The review further highlights on the types and methods of synthesis of aptamers before the discussion of the prospects, merits, and challenges in the use of aptamers for bioaffinity interactions with bioactive peptides.
The objective of this study is to investigate the effects of limited moisture content and storing temperature on the retrogradation of rice starch. Starch was gelatinized in various moisture contents (30-42%) and rice paste was stored at different temperatures (4 °C, 15 °C, 30 °C, -18/30 °C and 4/30 °C). X-ray diffraction (XRD) analysis revealed that after retrogradation, the crystalline type of rice starch changed from A-type to B + V type. The B-type crystallinity of retrograded rice starch under 30 °C was the highest among the five temperature conditions, and an increase in B-type crystallinity with increasing moisture content was observed. Differential scanning calorimetry (DSC) results revealed that rice starch retrogradation consists of recrystallization of amylopectin and amylose, and is mainly attributed to amylopectin. The higher moisture content was favorable for amylopectin recrystallization, whereas the moisture content had little effect on the amylose recrystallization. The optimal temperature for amylopectin and amylose recrystallization was 4 °C and 15 °C, respectively. The amylopectin recrystallization enthalpy of rice starch stored at 4/30 °C was mediated between 4 °C and 30 °C but always higher than that at -18/30 °C. On the whole, after being heated at 42% moisture content and stored at 4 °C, rice starch showed the maximum total retrogradation enthalpy (8.44 J/g).
Skin crack defects can develop in sandwich honeycomb composite structures during service life due to static and impact loads. In this study, the fracture behavior of sandwich honeycomb composite (SHC) beams containing crack at the skin was investigated experimentally and numerically under four-point loading. Three different arrangements of unidirectional (UD) carbon fiber composite and the triaxially woven (TW) fabric were considered for the skins. The presence of a 10 mm crack at mid-span of the top skin, mid-span of the bottom skin, and mid-way between load and support of the top skin, respectively, were considered. Failure load equations of the load initiating the skin crack extension were analytically derived and then numerically developed using the J-integral approach. The crack extension failure mode dominated all cracked specimens except those with low-stiffness skin which were controlled by the compressive skin debonding and core shear failures.
Biocompatible polymers have received significant interest from researchers for their potential in diagnostic applications. This type of polymer can perform with an appropriate host response or carrier for a specific purpose. The current study aims to fabricate and characterise poly(ethylene) oxide (PEO) nanofibres with different concentrations for cytotoxicity evaluation in human breast cancer cell lines (MCF-7) and to get an optimal PEO nanofibre concentration (permissible limit) as a suitable polymer matrix or carrier with potential use in diagnostic applications. The fabrication of PEO nanofibres was done using electrospinning and was characterised by structure and morphology, surface roughness, chemical bonding and release profiles. The functional effects of PEO nanofibres were evaluated with MTS assay and colony formation assay in MCF-7 cells. The results showed that viscosity plays a vital role in synthesising a polymer solution in electrospinning for producing beadless nanofibrous mats ranging from 4.7 Pa·s to 77.7 Pa·s. As the PEO concentration increases, the nanofibre diameter and thickness will increase, but the surface roughness will be decreased. The average fibre diameter for 5 wt% PEO, 6 wt% PEO and 7 wt% PEO nanofibres were 129 ± 70 nm, 185 ± 55 nm and 192 ± 53 nm, respectively. In addition, the fibre thickness for 4 wt% PEO, 5 wt% PEO, 6 wt% PEO and 7 wt% PEO nanofibres were 269 ± 3 μm, 664 ± 4 μm, 758 ± 7 μm and 1329 ± 44 μm, respectively. Contrarily, the surface roughness for 4 wt% PEO, 5 wt% PEO, 6 wt% PEO and 7 wt% PEO nanofibres were 55.6 ± 9 nm, 42.8 ± 6 nm, 42.7 ± 7 nm and 36.6 ± 1 nm, respectively. PEO nanofibres showed the same burst release pattern and rate due to the same molecular weight of PEO with a stable release rate profile after 15 min. It also demonstrates that the percentage of PEO nanofibre release increased with the increasing PEO concentration due to the fibre diameter and thickness. The findings showed that all PEO nanofibres formulations were non-toxic to MCF-7 cells. It is suggested that 5 wt% PEO nanofibre exhibited non-cytotoxic characteristics by maintaining the cell viability from dose 0-1000 μg/ml and did not induce the number of colonies. Therefore, 5 wt% PEO nanofibre is the optimal nanofibre concentration and was suggested as a suitable base polymer matrix or carrier with potential use for diagnostic purposes. The findings in this study have demonstrated the influence of cell growth and viability, including the effects of PEO nanofibre formulations on cancer progress characteristics to achieve a permissible PEO nanofibre concentration limit that can be a benchmark in medical applications, particularly diagnostic applications.
Dacryodes rostrata (kembayau) is an important food and oil resource for local communities in Borneo, but it is not commonly known to wider community. The objective of this work is to valorize kembayau fruit by evaluating the characteristics of the oil from the fruit. In this study, the physicochemical characteristics and the lipophilic essential nutrient; the fatty acid composition, vitamin E and beta-carotene content of oils obtained from the peel, pulp and seeds of kembayau fruits were studied. The pulp of the kembayau fruit contained highest proportion of oil, followed by peel and seed. Kembayau fruit contained vitamin E and had trace amount of beta-carotene. Besides, kembayau fruit oils were not toxic to BRL3A cells, provided hepatoprotection and reversed lipid peroxidation in paracetamol-induced toxicity. Our results suggest that kembayau can be a potential source for cooking oil as the physicochemical characteristics are comparable with commercial source such as oil palm.