Pengaruh Dimensi Benda Uji Terhadap Kuat Tekan Beton

Kuat tekan adalah karakteristik mekanik utama dari beton yang dapat diketahui melalui penelitian uji tekan di laboratorium terhadap benda uji. Baik dalam bentuk kubus ataupun silinder dengan ukuran standar: 10cm x 10cm x 10cm dan 15cm x 15cm untuk kubus dan 10cm x 20cm dan 15cm x 30cm untuk silinder. Untuk mendapatkan informasi mengenai kecendrungan harga kuat tekan beton dengan variasi dimensi benda uji, telah dilakukan penelitian-penelitian di laboratoriun untuk mendapatkan komposisi campuran tertentu pada umur beton 28 hari, variasi ukuran benda uji dibuat: 10cm x 10cm x 10cm, 12,5cm x 12,5cm x 12,5cm dan 15cm x 15cm x 15cm untuk kubus dan 10cm x 20cm, 12,5cm x 25cm dan 15cm x 30cm untuk silinder. Dengan jumlah benda uji masing-masing 20 buah untuk setiap ukuran benda uji. Melalui prosedur standar pengujian kuat tekan dan menggunakan formula-formula baku perhitungan tekan rata-rata diperoleh informasi bahwa peningkatan ukuran dimensi benda uji menghasilkan penurunan kuat tekan rata-rata, untuk benda uji kubus dengan ukuran masing-masing: 10cm x 10cm x 10cm, 12,5cm x 12,5cm x 12,5cm dan 15cm x 15cm x 15cm diperoleh kuat tekan rata-rata masing-masing: 32,86MPa, 31,26MPa dan 31,036MPa. Sedangkan untuk silinder dengan kururan 10cm x 20cm, 12,5cm x 25cm dan 15cm x 30cm diperoleh kuat tekan rata-rata masing-masing: 31,47MPa, 30,85MPa dan 30,44MPa

Effects of RASSF6 siRNA on gene expression in 3T3-L1 adipocytes.

<p><i>A</i>–<i>C</i>, 3T3-L1 adipocytes were treated with MDI and differentiated into mature adipocytes as described under “Materials and Methods”. Differentiated 3T3-L1 adipocytes were transfected with luciferase siRNA (<i>Siluc</i>) or RASSF6 siRNA (<i>SiRassf6</i>). After 2 days of transfection, total RNAs were extracted and subjected to quantitative PCR analysis to examine expression levels of RASSF6, HMGA2 and CD44 mRNAs. The level of β-actin (<i>β-actin</i>) transcript was used as a control. *<i>P</i><0.05 compared with those of cells transfected with control siRNA (<i>Siluc</i>).</p

RASSF6 Expression in Adipocytes Is Down-Regulated by Interaction with Macrophages

<div><p>Macrophage infiltration into adipose tissue is associated with obesity and the crosstalk between adipocytes and infiltrated macrophages has been investigated as an important pathological phenomenon during adipose tissue inflammation. Here, we sought to identify adipocyte mRNAs that are regulated by interaction with infiltrated macrophages <i>in vivo</i>. An anti-inflammatory vitamin, vitamin B6, suppressed macrophage infiltration into white adipose tissue and altered mRNA expression. We identified >3500 genes whose expression is significantly altered during the development of obesity in db/db mice, and compared them to the adipose tissue mRNA expression profile of mice supplemented with vitamin B6. We identified <i>PTX3</i> and <i>MMP3</i> as candidate genes regulated by macrophage infiltration. PTX3 and MMP3 mRNA expression in 3T3-L1 adipocytes was up-regulated by activated RAW264.7 cells and these mRNA levels were positively correlated with macrophage number in adipose tissue <i>in vivo</i>. Next, we screened adipose genes down-regulated by the interaction with macrophages, and isolated <i>RASSF6</i> (<i>Ras association domain family 6</i>). RASSF6 mRNA in adipocytes was decreased by culture medium conditioned by activated RAW264.7 cells, and RASSF6 mRNA level was negatively correlated with macrophage number in adipose tissue, suggesting that adipocyte RASSF6 mRNA expression is down-regulated by infiltrated macrophages <i>in vivo</i>. Finally, this study also showed that decreased RASSF6 expression up-regulates mRNA expression of several genes, such as <i>CD44</i> and <i>high mobility group protein HMGA2</i>. These data provide novel insights into the biological significance of interactions between adipocytes and macrophages in adipose tissue during the development of obesity.</p> </div

Effect of decreased RASSF6 expression on gene expression in 3T3-L1 adipocytes.

<p>DNA microarray analysis was repeated with the Cy3 and Cy5 dyes reversed (a dye swap), and fold change (<i>Fold</i>) represents the average of mRNA expression level in RASSF6-deprived 3T3-L1 adipocytes relative to control cells.</p

Effects of dietary vitamin B6 on adipose gene expression in HFD mice.

<p><i>A</i>,<i>B</i>, Semiquantitative RT-PCR was performed to determine mRNA levels of genes related to macrophages. 3T3-L1 preadipocytes were treated with MDI for 48 h and differentiated into mature adipocytes as described under “Materials and Methods”. RAW264.7 cells were stimulated with 1 µg/ml of LPS for 18 hr. Mature adipocytes and SVF were isolated from white adipose tissue of HFD mice as described under “Materials and Methods”. The level of Emr1 (F4/80) transcript was used as a control for macrophages. <i>C</i>,<i>D</i>,<i>F–H</i>, Total RNA from individual mice (n = 12) in two groups was subjected to quantitative PCR to examine mRNA expression level of selected genes. All values are normalized to β-actin levels. The data (mean ± S.E.) are representative of three independent experiments. *<i>P</i><0.05, **<i>P</i><0.01 compared with those of 1 mg/kg PN (<i>1</i>). <i>E</i>, The number of F4/80-positive cells in the epididymal adipose tissue was examined by F4/80 immunostaining as described under “Materials and Methods”.</p

Effect of vitamin B6 supplementation on adipose tissue gene expression in mice fed a high fat diet.

<p>List of differentially expressed genes grouped into functional categories. DNA microarray analysis was repeated with the Cy3 and Cy5 dyes reversed (a dye swap), and fold change (<i>Fold</i>) represents the average of mRNA expression level in mice with a 35 mg PN HCl/kg diet relative to a 1 mg PN HCl/kg diet.</p

Analysis of two transcriptomes to isolate genes whose expression is upregulated by the interaction with macrophages.

<p>DNA microarray analysis was repeated with the Cy3 and Cy5 dyes reversed (a dye swap). Fold change (<i>Fold 1</i>) represents the average of mRNA expression level in db/db mice relative to db/+ mice. Fold change (<i>Fold 2</i>) represents the average of mRNA expression level in mice with a 35 mg PN HCl/kg diet relative to a 1 mg PN HCl/kg diet.</p

PTX3 and MMP3 expression in adipocytes is affected in the presence of activated macrophages.

<p><i>A</i>, Illustration of the coculture system composed 3T3-L1 adipocytes and RAW264.7 cells is shown. <i>B</i>, Semiquantitative RT-PCR was performed to determine mRNA levels of <i>PTX3</i> and <i>MMP3</i>. The level of β-actin (<i>β-actin</i>) transcript was used as a control. <i>C</i>,<i>D</i>, Total RNAs from 4 groups was extracted and subjected to quantitative PCR to examine mRNA expression level of <i>PTX3</i> and <i>MMP3</i>. All values are normalized to β-actin levels. The data (mean ± S.E.) are representative of two independent experiments. **<i>P</i><0.01 compared with those of group C. <i>E</i>,<i>F</i>, The relative mRNA expression level of each gene was determined by quantitative PCR and normalized to β-actin level. Pearson's correlation coefficient showed a positive correlation between MMP3 and PTX3 mRNA levels and number of <i>F4/80</i> positive cells in adipose tissue of mice fed HFD. <i>G</i>,<i>H</i>, Semiquantitative RT-PCR was performed to determine mRNA levels of PTX3 and MMP3. 3T3-L1 preadipocytes were treated with MDI for 48 h and differentiated into mature adipocytes as described under “Materials and Methods”. RAW264.7 cells were stimulated with 1 µg/ml of LPS for 18 hr. Mature adipocytes and SVF were isolated from white adipose tissue of HFD mice as described under “Materials and Methods”.</p