UJI HEDONISME SEDIAAN GEL ANTIJERAWAT DARI JERUK NIPIS

Clean, smooth, and disease-free facial skin is a dream. However, the reality is that many people have skin problems. The skin problem that often occurs is acne. One way to treat acne is by using herbal preparations. Herbal plants that have anti-acne properties include Citrus aurantiifolia and menthol. The purpose of this study was to make antiacne gel preparations from Citrus aurantiifolia and menthol. There are also stages of this research, including formula making, production and physical evaluation of preparations to obtain the best dosage formulas. In addition, the determination of the optimum stability and formula is obtained from the physical evaluation of the gel preparation which includes organoleptic and hedonism test. Keyword : herbal, Citrus aurantiifolia, menthol, hedonism test

Expression and characterization of family 40 Carbohydrate Binding Module (CBM) from Vibrio cholerae Non-O1 sialidase

Carbohydrate Binding Module (CBM) is a non-catalytic protein domain found in carbohydrate-active enzyme (glycoside hydrolase) and its role is to bring carbohydrates in close proximity to the enzyme catalytic site for complete hydrolysis. The removal of this CBM from most protein domains often leads to reduced enzyme activity and efficiency. In this study, a gene encoding for family 40 CBM from Vibrio cholerae Non-O1 sialidase was cloned and successfully expressed in E. coli BL21 (DE3) strain. The CBM40 encoded 195 amino acids with 585 bp of nucleotide sequence. The protein was successfully expressed at 18°C when induced with 1 mM IPTG. Maximum expression was achieved at 20 hours after post-induction time. For purification of the protein, an anionic denaturing detergent method was used containing 1% SDS and 0.1% sarkosyl with gradient affinity elution at 50 mM imidazole concentrations. SDS-PAGE analysis of the purified CBM40 protein displayed a protein band with a molecular mass of 21 kDa. Protein characterization showed optimum stability in 100 mM citrate buffer pH 5.5, with the highest Tm value of 40 °C. The protein was stable between pH 5.5–6.2 and able to retain its activity at 27–56°C. The addition of Mn2+ and Mg2+ increased the protein melting temperature to 56°C. Meanwhile, the addition of reagents, such as 1% SDS and 1 M urea increased the protein melting temperature (Tm) to approximately 55°C. Protein stability can be influenced by many factors, including different buffers, pHs, temperatures, ionic strengths, and chemical reagents used in a study. The optimum characterization conditions established would further lead to the discovery of CBM40 protein true potential in enhancing substrate binding affinity and protein-carbohydrate recognition, which underpins its broad applications in biotechnology and protein engineering fields.

CORRELATION OF ASPHALTENE SOLVATION WITH STABILITY OF CRUDE OIL EMULSION USING SCALING EQUATIONS

Due to the simplicity of scaling equations and its applicability to colloid chemistry, the scaling theory is widely used in studying emulsion properties such as force profiles. Scaling equations were developed for the studied samples for correlation of asphaltene solvation with stability of crude oil emulsions. Correlations were made for viscosity and percentage water resolved by varying the volume concentration of toluene in heptol mixture that was used as solvent for the asphaltene re-dissolution. The study shows that tuning the composition of heptol allows fine control of colloidal forces between asphaltene surfaces in an organic solvent and therefore determines the stability state of the emulsion. Statistically derived correlation equations provide for a range in the aromaticity of the crude medium for which an optimum stability is observed and therefore gives good understanding on the control of emulsion stability. The study further shows that emulsion inversion can be achieved by adjusting the concentration of surfactant.

Improving Dispersion of Recycled Discontinuous Carbon Fibres to Increase Fibre Throughput in the HiPerDiF Process

In order to increase the material throughput of aligned discontinuous fibre composites using technologies such as HiPerDiF, stability of the carbon fibres in an aqueous solution needs to be achieved. Subsequently, a range of surfactants, typically employed to disperse carbon-based materials, have been assessed to determine the most appropriate for use in this regard. The optimum stability of the discontinuous fibres was observed when using the anionic surfactant, sodium dodecylbenzene sulphonate, which was superior to a range of other non-ionic and anionic surfactants, and single-fibre fragmentation demonstrated that the employment of sodium dodecylbenzene sulphonate did not affect the interfacial adhesion between fibres. Rheometry was used to complement the study, to understand the potential mechanisms of the improved stability of discontinuous fibres in aqueous suspension, and it led to the understanding that the increased viscosity was a significant factor. For the shear rates employed, fibre deformation was neither expected nor observed.

Karakteristik Marshall Pada Campuran Asphalt Concrete – Wearing Course (AC-WC) Dengan Penambahan Styrofoam

Styrofoam waste presents the environment issue because it is difficult to decompose. As an effort to recycle this pollutant, styrofoam can be utilized as an additive in asphalt concrete mixture. The use of additives aims to create a flexible pavement layer having good performance and meet the requirements. The purpose of this study is to find out whether the addition of styrofoam can improve the quality of asphalt mixtures, and look for alternative additives that can increase asphalt pavement performance. In this study, researchers used food container styrofoam as an addition and incorforated into Asphalt Concrete Wearing Course (AC-WC) mixture. The styrofoam content was 6.5%; 6.75%; 7% ; 7.25%; and 7.5% of asphalt weight. The optimum asphalt contentused is 5.5%. The value of the optimum stability was 3126,002 kg, found at 7.25% of styrofoam content. The best results of Marshall test was obtained at 6.5% of styrofoam content with stability value 1362,045 kg, VIM value 4,96%, VMA 15,025%, VFA 67,800%, flow 3,44 mm, and MQ 416,338 kg / mm.

Screening, Production and Partial Characterization of a Thermostable Laccase from Trametes sp. Isolate B7 with Biotechnological Potentials

The search for efficient and green oxidation technologies has increased interest in utilization of laccases in non conventional methods. Laccases catalyze a wide range of substrates due to low substrate specificity and strong oxidative potentials. Challenges to large-scale enzyme utilization include, low enzyme activity and instability which restrict use in many areas of biotechnology. In the study, 59 fungi comprising Aspergillus niger (40%), Trichoderma harzianum (31%), Aspergillus flavus (9.0%), Trichoderma viride (5.0%), Fusarium oxysporum (5.0%), Rhizopus stolonifer (5.0%), Trametes sp. (3.0%) and Aspergillus nidulans (2.0%) were isolated and screened for laccase production. Plate screening test showed 57.5%, 34.0% and 8.5% of fungi were laccase-positive on ABTS, Guaiacol, and α-naphthol agar respectively. Isolates were further screened in liquid cultures, and the highest laccase producer identified molecularly. Trametes sp isolate B7 was selected for solid state fermentation (SSF). Laccase production in SSF was highest at pH 5.0 (2356 U/mL). The purified laccase showed high activity (pH 3.0 - 6.0) and stability (pH 3.0 - 8.5) using ABTS. It was active (20 - 80°C) and thermostable (30 - 80°C) with optimum stability at 70°C (100% for 1 hour). The percentage decolourization of Phenol red were 28% and 36% using 1000 U/mL and 2000 U/mL crude laccases respectively. Similarly, RBBR (100%), Congo red (75%) and Malachite green (62%), and 77.4%, 64% and 28% were decolourized using 1000 U/mL and 2000 U/mL crude laccases respectively. ABTS agar was very reliable in large-scale screening for laccase which possessed thermostable property and degraded synthetic dyes without use of enzyme mediators. These attribute made the enzyme suitable for application in industry and biotechnology.

Biomechanical evaluation of pin placement of external fixator in treating tranverse tibia fracture: Analysis on first and second cortex of cortical bone

Biomechanical perspective of external fixator is one of the greatest factor to consider in successfully treating bone fracture. This is due to the fact that mechanical behavior of the structure can be analyzed and optimized in order to avoid mechanical failure, increase bone fracture healing rate and prevent pre-term screw loosening. There are three significant factors that affect the stability of external fixator which are the placement of pin at the bone, configuration and components of external fixator. These factors lead to one question: what is the optimum pin placement in which exerts optimum stability? To date, literature on above mentioned factors is limited. Therefore, we conducted a study to evaluate the uniplanar-unilateral external fixator for two different pin placement techniques in treating transverse tibia fracture via finite element method. The study was started off with the development of transverse tibia fracture using Mimics software. Computed tomography (CT) data image was utilized to develop three dimensional tibia bone followed by crafting fracture on the bone. Meanwhile, the external fixator was developed using SolidWork software. Both tibia bone and external fixator were meshed in 3-matic software with triangular mesh element. Simulation of this configuration was took place in a finite element software, Marc.Mentat software. A load of 400 N was applied to the proximal tibia bone in order to simulate stance phase of a gait cycle. From the findings, the pin placement at the second cortex of bone provided optimum stability in terms of stress distribution and displacement, which should be considered for better treatment for transverse tibia fracture. On the other hand, the pin placement at first cortex should be avoided to prevent many complications.

Formulation and evaluation of prazosin hydrochloride loaded solid lipid nanoparticles

Solid Lipid Nanoparticles (SLN) are rapidly developing field of nanotechnology with several potential application in drug delivery and research. Drugs having low aqueous solubility not only give low oral bioavailability but provide high inter-and intra subject variability. The purpose of the present study was to investigate the bioavailability enhancement of Prazosin Hydrochloride drug by formulating solid lipid nanoparticle. Prazosin Hydrochloride Drug is an antihypertensive drug with limited bioavailability so that solid lipid nanoparticle (SLN) is one of the approaches to improve bioavailability. SLN were prepared using glyceryl monostearate by hot homogenization followed by Solvent emulsification-ultrasonication. Prazosin Hydrochloride loaded SLN were characterized and optimized by parameters like particle size, zeta potential, XRD, DSC. Proposing Hydrochloride loaded SLN having the particle size 263.8±1.88 and entrapment efficiency 89.29±0.65% shows better bioavailability and optimum stability in studies. The SLN studies prepared using glyceryl mono stearate as a lipid and Polaxamer 407 as a polymer leads to improve bioavailability of the drug. Keywords: Prazosin Hydrochloride, Solid Lipid Nanoparticles, Entrapment efficiency, DSC

Formation and Characterization of Lactoferrin-Hyaluronic Acid Conjugates and Their Effects on the Storage Stability of Sesamol Emulsions

The purpose of this study was to fabricate biopolymer conjugates from lactoferrin (LF) and hyaluronic acid (HA) and then to investigate their potential as emulsifiers for forming sesamol-loaded emulsions. Initially, LF-HA covalent conjugates were formed using the carbodiimide coupling method in aqueous solutions at pH = 4.5, and then the nature of the conjugates was investigated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy, and fluorescence spectroscopy. The results demonstrated the formation of an amide link between the amine groups of LF and the carboxyl groups of HA. Sesamol emulsions were prepared using the LF-HA conjugates as emulsifiers and their stability was determined. The conjugates improved both the physical and chemical stability of the emulsions during storage. Optimum stability of the emulsion was obtained at a LF-to-HA molar ratio of 2:1. Our results suggest that LF-HA conjugates may be effective emulsifiers for use in food stuffs and other applications.