Biosorption of chromium (VI) by chitosan-immobilized acinetobacter haemolyticus

In this study, the ability of chitosan-immobilized Acinetobacter haemolyticus as biosorbent for chromium (VI) biosorption in batch system was investigate. Optimized parameter namely pH, contact time, biosorbent dosage and initial metal concentration obtained from the experiment was then applied for electroplating wastewater treatment. Biosorption using chitosan-immobilized Acinetobacter haemolyticus at pH 3, 8 hours contact time, 3% (w/v) of biosorbent dosage with 100 mg L 1 initial metal concentration resulted in maximum chromium (VI) uptake of 0.2 mg g 1. Using electroplating wastewater, the biosorption capacity of the chitosan immobilized Acinetobacter haemolyticus was 0.27 mg g 1 at pH 3 which is higher than unmodified pH

Effect of PVP as a capping agent in single reaction synthesis of nanocomposite soft/hard ferrite nanoparticles

Nanocomposite magnets consist of soft and hard ferrite phases are known as an exchange spring magnet when they are sufficiently spin exchange coupled. Hard and soft ferrites offer high value of coercivity, Hc and saturation magnetization, Ms respectively. In order to obtain a better permanent magnet, both soft and hard ferrite phases need to be “exchange coupled”. The nanoparticles were prepared by a simple one-pot technique of 80% soft phase and 20% hard phase. This technique involves a single reaction mixture of metal nitrates and aqueous solution of varied amounts of polyvinylpyrrolidone (PVP). The heat treatment applied was at 800 °C for 3 h. The synthesized composites were characterized by Transmission Electron Microscope (TEM), Fourier Transform Infra-red (FT-IR), Energy Dispersive X-Ray (EDX), X-ray diffraction (XRD) and Vibrating sample magnetometer (VSM). The coexistence of two phases, Ni0.5Zn0.5Fe2O4 and SrFe12O19 were observed by XRD patterns. It also verified by the EDX that no impurities detected. The magnetic properties of nanocomposite ferrites for 0.06 g/ml PVP gives a better properties of Hc 932 G and Ms 39.0 emu/g with average particle size obtained from FESEM was 49.2 nm. The concentration of PVP used gives effect on the magnetic properties of the samples

Synthesis and characterization of magnetic properties of hard/soft nanocomposite permanent magnets

We report on an investigation of the magnetic properties of nanocomposite ferrite via different technique. Magnetic hard and soft ferrite, SrFe12O19/ Ni0.5Zn0.5Fe2O4 nanocomposites with mass ratio 4:1 were synthesised by using the mechanical alloying (750 rpm) method, physical mixing and high energy ball milling method. The nanocomposite ferrite was calcined at different temperatures from 500°C to 800°C to study the effect of calcination temperature on the magnetic properties of nanocomposite ferrite. The X-Ray Diffraction (XRD) result shows the double phase SrFe12O19 and Ni0.5Zn0.5Fe2O4 existed. The Transmission Electron Microscopy (TEM) image shows the particlesize is agglomerated, due to the attractive force. The magnetisation measurement was obtained at room temperature by using a Vibrating Sample Magnetometer (VSM). For mixing by mechanical alloying, nanocomposite ferrite at 800°C gives the larger value of magnetisation, Ms 46 emu/g which is higher than the Ms of a single phase of SrFe12O19, 37 emu/g. The remanence ratio, Mr/Ms of nanocomposite ferrite at 800°C gives the value more than 0.5, this proves that the exchange coupling exists with the higher value of Ms. For physical mixing, the highest magnetisation obtains are 51 emu/g at a temperature of 750°C. From this simple technique, we are able to attain good magnetic properties of nanocomposite ferrite nanoparticles with a particle size below 50 nm

Teori-Teori Konsep Kendiri

Cara berfikir dan tingkah laku seseorang pelajar dipengaruhi oleh konsep kendirinya. Konsep kendiri yang positif akan menghasilkan keyakinan diri yang tinggi, dan mempengaruhi kejayaan diri seseorang pelajar. Namun, sebahagian pelajar kurang berkeyakinan dan menunjukkan sikap yang pasif sama ada di dalam atau di luar sekolah

Characterization of palm oil mill secondary effluent (pomse)

This paper reports on the characteristics of the Palm Oil Mill Secondary Effluent (POMSE) in four different period of sampling. The aim of this study was to measure the value of the Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD5), color, total suspended solid (TSS), turbidity, iron ferrous, and total iron in POMSE. These basic parameters are crucial in determining a suitable treatment system to be acted on the wastewater so that the optimum condition of the treatment could be obtained. Results obtained in this study indicated that BOD5 concentration lies between 249 to 267mg/L; COD reading were between 3234 to 3624mg/L; Color were between 3860 to 5350ADMI ; total iron were between 0.24 to 1.75mg/L; ferrous iron were 1.75mg/L; TSS were between 1635 to 1875 and turbidity, 2865 to 2894NTU. Results suggest that aerobic and anaerobic treatment were not sufficient in reaching the standard discharged limit set by Department of Environment (DOE) Malaysia

Pembentukan modal insan: hubungan konsep kendiri, personaliti, dan pencapaian akademik pelajar sekolah menengah

Kajian ini bertujuan untuk mengenal pasti hubungan antara konsep kendiri dan personaliti dengan pencapaian akademik dalam kalangan pelajar sekolah. Seramai 270 orang pelajar dipilih berdasarkan kaedah persampelan rawak berkelompok di enam buah sekolah menengah di daerah Kluang, Johor. Kajian rintis dijalankan untuk melihat kebolehpercayaan dan kesesuaian soal selidik. Manakala Alpha Cronbach digunakan untuk mengukur kebolehpercayaan soal selidik. Nilai kebolehpercayaan Alpha Cronbach bagi keseluruhan soal selidik ini adalah 0.8432. Soal selidik berkaitan konsep kendiri diubah suai daripada Skala Konsep Kendiri Tennessee daripada Fitts & Wareen (1996). Manakala soal selidik bagi jenis personaliti pelajar pula diubah suai daripada Soal Selidik Personaliti daripada Eysenck & Eysenck (1975). Statistik deskriptif iaitu kekerapan, peratus, dan min digunakan untuk menganalisis dimensi konsep kendiri pelajar paling dominan. Selain itu, statistik inferensi iaitu ujian-t juga digunakan untuk menganalisis perbezaan antara dimensi konsep kendiri dan personaliti mengikut jantina. Manakala statistik inferensi iaitu korelasi Pearson pula digunakan pada aras signifikan 0.05 bagi menganalisis hubungan antara konsep kendiri dan personaliti dengan pencapaian akademik pelajar. Dapatan kajian ini menunjukkan dimensi konsep kendiri paling dominan dalam kalangan pelajar ialah dimensi konsep kendiri seperti keluarga. Selain itu, analisis ujian-t menunjukkan tidak terdapat perbezaan yang signifikan antara dimensi konsep kendiri dan personaliti mengikut jantina. Analisis korelasi Pearson pula mendapati tidak terdapat hubungan yang signifikan antara dimensi konsep kendiri dan personaliti dengan pencapaian akademik. Oleh itu, beberapa cadangan telah dikemukakan bagi meningkatkan konsep kendiri dan juga kecenderungan personaliti pelajar yang positif dalam usaha meningkatkan pencapaian akademik mereka

Equilibrium studies and dynamic behaviour of cadmium adsorption by magnetite nanoparticles extracted from mill scales waste

The main objective of the current work is to investigate the adsorption mechanism of magnetite that has been extracted from mill scale waste, for the removal of cadmium ions from the aqueous solution. The mill scale was grounded for 24 h in conventional milling and then milled 8 h in high energy ball milling to get nanoparticles. The characterizations of the magnetite mill scale nano adsorbents (MMSNA) were done with a high-resolution transmission electron microscope, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, Brunauer- Emmett-Teller and zeta sizer. The magnetite nanoparticles from this work are crystallite, with irregularly shaped particles, a relatively low specific surface area of 4.02 m2/g, and have an isoelectric point at pH value 5.8. Comprehensive adsorption studies were performed to investigate the adsorption of cadmium ions on the MMSNA, including the evaluation of kinetics and isotherms, the effect of pH, contact time, and mass of adsorbent. The optimal time for removal was 30 min, although the adsorption reached equilibrium within 15 min, which was found to fit well with the pseudo-secondorder and Langmuir model. The maximum Langmuir adsorption capacity of the adsorbent was about 3.06 mg/g. The adsorbent was regenerated using a little acidic deionised water and cadmium ions removal of 90% after 5 cycles, which confirms the chemical stability and reusability of the manufactured nanoparticles. The results and analysis of the MMSNA suggest that it can be one of the potential adsorbents for magnetic separation in wastewater treatment

Synthetic Curcumin Derivative DK1 Possessed G2/M Arrest and Induced Apoptosis Through Accumulation of Intracellular ROS in MCF-7 Breast Cancer Cells

Curcumin is a lead compound of the rhizomes of Curcuma longa and possess a broad range of pharmacological activities. Chemically, curcumin is 1,3-dicarbonyl class of compound, which exhibits keto-enol tautomerism. Despite of its strong biological properties, curcumin has yet been recommended as a therapeutic agent because of its poor bioavailability. A curcumin derivative (Z)-3-hydroxy-1-(2-hydroxyphenyl)-3-phenylprop-2-en-1-one (DK1) was synthesized and its cytotoxicity was tested on breast cancer cell MCF-7 and normal cell MCF-10A using MTT assay. Meanwhile, cell cycle regulation and apoptosis on MCF-7 cell were evaluated using flow cytometry. Regulation of cell cycle and apoptosis related genes expression was investigated by quantitative real time polymerase chain reaction (qRT-PCR), western blot and caspases activity analyses. Activation of oxidative stress on MCF-7 were evaluated by measuring ROS and GSH levels