Judul: Pengaruh konsentrasi dan lama perebusan terhadap penetrasi dan retensi bahan pengawet diffusol-CB pada kayu durian
Abstrak: Kayu-kayu yang berasal dari hutan rakyat kini mulai banyak digunakan karena semakin langkanya ketersediaan kayu dari hutan alam. Salah satu contoh dan yang juga digunakan dalam penelitian ini adalah kayu durian (Durio zibethinus Murr.) asal Desa Cibeureum, Dramaga, Bogor. Dengan kelas awet yang rendah (Kelas IV-V) dan keterawetan yang sukar maka penggunaan kayu ini sangat terbatas. Agar pemakaian kayu durian menjadi lebih maksimal, maka kayu perlu diawetkan. Karena keterawetannya sukar, sebelum diawetkan kayu harus diberi perlakuan awal. Dengan demikian, penelitian ini bertujuan untuk mempelajari pengaruh perbedaan lama waktu perebusan (30-, 60-, dan 90 menit) dan perbedaan konsentrasi larutan bahan pengawet Diffusol-CB (3-, 4-, dan 5%) terhadap penetrasi dan retensi. Dari perlakuan tersebut diharapkan ditemukan perlakuan yang memberikan nilai penetrasi dan retensi yang optimal. Metode pengawetan yang digunakan adalah metode rendaman dingin, sedangkan rancangan percobaannya adalah rancangan faktorial berblok. Analisis lanjutan dilakukan dengan uji wilayah berganda Duncan dimana kombinasi perlakuan ditetapkan sebanyak 3 kali ulangan. Sebagai blok adalah bagian batang yaitu pangkal, tengah dan ujung. Dari hasil penelitian diketahui bahwa hanya unsur boron yang masuk ke dalam kayu dengan nilai rata-rata keseluruhan berkisar antara 0,43-0,86 cm. Bagian batang, konsentrasi larutan bahan pengawet, lama perebusan, dan interaksi antara konsentrasi bahan pengawet dan lama perebusan semuanya tidak berpengaruh secara nyata terhadap nilai penetrasi. Rata-rata penetrasi kayu yang tidak direbus (kontrol) lebih rendah dibandingkan penetrasi kayu yang direbus; berturut-turut 0,50 cm dan 0,65 cm (pangkal); 0,72 cm dan 0,74 cm (tengah); dan 0,70 cm dan 0,74 cm (ujung). Secara keseluruhan rata-rata penetrasi pada kayu yang tidak direbus adalah 0,64 cm, sedangkan pada kayu yang direbus sebesar 0,71 cm. Penetrasi terdalam (0,77 cm) terdapat pada kayu yang direbus selama 60 menit dan diawetkan dengan bahan pengawet berkonsentrasi 5%.
Keyword: Kayu durian, Perebusan, Penetrasi, Retensi

Judul: Pengaruh Konsentrasi Bahan Pengawet Boron terhadap Retensi dan Penetrasi pada Kayu Rakyat
Abstrak: INTRODUCTION. Nowadays, wood supply from natural forest continues to decrease. It resulted in the development of community forest in many areas in Indonesia. In general, community forest has been developing using fast-growing species. The wood obtained is generally inferior compared to that from the natural forest, particularly in term of natural durability and strength. Therefore, it is necessary to improve the quality of such kind of woods. The aims of the research were to determine the natural durability of wood species from community forest and to evaluate effect of boron concentration onto retention and penetration of these species. Wood natural durability was evaluated after exposing the samples in the field for 3 months following the procedure of American Standard for Testing and Material (ASTM) D 1756 2008. MATERIALS AND METHOD. The main materials used were the wood of durian (Durio zibethinus), karet (Hevea brasiliensis), manii (Maesopsis eminii) and petai (Parkia speciosa) from small business unit of sawmill in Cinangneng, Bogor. The others are boron with three concentrations (5%, 10% and 15%) as the preservative, and curcuma extract, alcohol, chloric acid (HCl), aquades and salicylic acid as dying solution. Preservation process applied was cold bath method for 2 hours. Retention and penetration were used as the indicator. Data was then analyzed using experimental design factorial randomly by two factors (wood species and boron concentration) with three replications. RESULT AND DISCUSSIONS. The result showed that natural durability of all wood species studied was low. It belongs to Durability Class of IV and V. This indicates that all wood species need to be enhanced through the preservation. Based on this study it showed that petai wood has the highest value of the retention (4.31 kg/m3), while durian wood was the lowest (2.37 kg/m3). Retention value of karet wood, known is rubberwood, was almost similar to that of manii wood. Result also showed that penetration value of all wood species studied were almost similar namely 50.13% (durian), 51.55% (karet), 51.57% (petai) and 52.78% (manii). The results indicate that retention value was influenced by wood species, boron concentration and the interaction of these two factors, while penetration value was only affected by the concentration. Factors of wood species which affect the retention are related to the anatomical structure, as well as the existence and the amount of free hydroxyl group (-OH-) that are present in the cell wall components. In general, retention and penetration values tend to increase with the increasing of boron concentration. In all wood species studied, the concentration of 15% resulted in the highest of retention and the deepest of penetration.
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Judul: Mathematical model of Hematopoietic Stem Cell in Chronic Myelogenous Leukemia with and without Therapy
Abstrak: Leukemia or blood cancer is a diverse group of neoplastic disease, characterized by the multiplication of abnormal leukocytes or malignant transformation of blood-forming cells in bone marrow and lymphoid tissues. One of the most common types of leukemia is Chronic Myelogenous Leukemia (CML), which is usually diagnosed by the presence of certain chromosomal abnormalities, the so-called Philadelphia chromosome (Ph). One of the treatments of CML is Granulocyte Colony-Stimulating Factor (G-CSF). In this paper, we discuss two Hematopoietic Stem Cell (HSC) models, i.e. HSC without treatment and HSC with G-CSF treatment. The model of HSC without treatment included three equations representing the dynamics of HSC, leukocyte and platelet. Whereas, the model of HSC with G-CSF treatment includes the previous three equations and adds two more equations representing G-CSF injection and G-CSF circulation. The stability behavior of the system approaching the equilibrium points in the simulation study is carried out using Mathematica 7.0. The simulation results show that the G-CSF treatment can successfully decrease the number of HSC, which means reducing the CML.
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