Pengembangan Perangkat Pembelajaran Matematika Kelas Rendah Berorientasi Model Pembelajaran Diskusi

This development was aimed at creating learning device for low level mathematics to increase the students\u27 participation and achievement through discussion learning model in Class A of the second semester of the Elementary School Teacher Education Department of Muhammadiyah University of Purwokerto of the academic year 2008/2009. The 49 subject takers was divided into 15 groups of 3 to 4 people. The procedure of developing the device used classroom action research. The action consisted of two cycles and took three months. Each cycle was done depending on the obtained improvement, design and the factor to be developed. The instrument which was used to get the data of participation and students\u27 response towards the lecture and the learning device was questioner, while he instrument to get data on students learning achievement were essay quiz, mid term test, and the end term test. The result was the device for learning low level mathematics, early-class learning material, students work, and increased learning participation. The learning achievement was still low which was due to their low ability in solving mathematical problem. Key words: Discussion learning model, participation, and mathematics learning achievement

Additional file 1: Table S1. of SAG-QC: quality control of single amplified genome information by subtracting non-target sequences based on sequence compositions

Sensitivity and specificity of our approach to discriminate non-target sequences. (XLSX 34 kb)ďť

Image_1_Abiotic Factors Promote Cell Penetrating Peptide Permeability in Enterobacteriaceae Models.pdf

Conventionally, the delivery of biomolecules into bacteria for the generation of characterized or functional mutants has relied greatly on horizontal gene transfer techniques. However, the low compatibility of these techniques with novel or hard-to-transform bacteria currently serves as a challenge to the bioengineering field. Here, we explored the use of cell penetrating peptides (CPPs) as an alternative biomolecule delivery approach by investigating the effects of the abiotic factors during CPP permeation. Using the (KFF)3K-FAM conjugate and Escherichia coli as models, we evaluated four abiotic factors where two of these factors, temperature and solution tonicity, promoted (KFF)3K-FAM permeation efficiency. Our data show that optimal (KFF)3K-FAM permeation efficiency was achieved for E. coli at approximately 98.1% under conditions of 37°C (growth optimal temperature) and 50% PBS concentration. Based on these conditions, we subsequently tested the applicability of CPP permeation in various bacterial strains by treating 10 bacterial strains from the Enterobacteriaceae family among which seven strains have no CPP permeation records with (KFF)3K-FAM. Interestingly, when compared with non-optimized conditions, all 10 strains showed a marked increase in CPP permeation ranging between 20 and 90% efficiency. Although using strains within Enterobacteriaceae that are phylogenetically close, our results hinted on the possibility that with proper optimization of the abiotic factors, CPPs could be compatible with a broad range of bacterial strains. Our efforts suggest that CPP could serve as an effective alternative approach for mutant generation and for biomolecule delivery into novel or hard-to-transform bacteria.</p

High-Density Microcavity Array for Cell Detection: Single-Cell Analysis of Hematopoietic Stem Cells in Peripheral Blood Mononuclear Cells

Detection and isolation of specific cell types from limited biological samples have become a major challenge in clinical diagnosis and cell biology research. Here, we report a high-density microcavity array for target cell detection in which thousands of single cells were neatly arrayed onto 10 000 microcavities with high efficiency at approximately 90% of the loaded cells. Cell-specific immunophenotypes were exclusively identified at the single-cell level by measuring fluorescence intensities of cells labeled with antibodies targeting cell surface markers, and the purity of hematopoietic stem cells (HSCs) within human peripheral blood analyzed by this system was correlated with those obtained by conventional flow cytometry. Furthermore, gene expression of the stem cell marker, CD34, was determined from HSCs by isolating single cells using a micromanipulator. This technology has proven to be an effective tool for target cell detection and subsequent cellular analytical research at the single-cell level

DataSheet_1_Approaches for attaining clean bacterial fractions from complex environmental samples.docx

Marine bacteria have been targeted by industry and pharmaceutics as genetic resources for highly active enzymes or novel lead compounds. Although numerous techniques have been introduced to isolate useful bacteria from the environment, we are still highly dependent on the conventional direct cultivation method to attain pure cultures. However, efficient bacterial isolation is hindered by several factors, including the presence of impurities. In this work, to demonstrate the significance of removing impurities and their impact on bacterial isolation, we employed two approaches: dielectrophoresis (DEP) and fluorescent D-amino acids (FDAA). We successfully attained clean bacterial fractions applicable for downstream processing using these approaches, uniquely designed to identify bacteria based on their characteristics and features. The diversity of bacteria attained by both approaches was investigated using 16S rRNA sequencing and compared to that attained by the standard differential centrifugation method. In addition, the viability of the isolates was also determined via direct cultivation. As a result, the separation of bacteria from impurities allowed for the identification of novel and useful bacteria unique to each approach. Successful cultivation also suggested that both approaches were applicable for attaining viable bacteria. In conclusion, removing impurities to attain clean bacterial fractions promotes the isolation of novel bacteria and thus could aid in the successful isolation of useful bacteria within complex environmental samples.</p

Droplet MDA of low-input lambda DNA.

<p>(a) Sequential fluorescent images of droplets encapsulating lambda DNA at a concentration of 265 ag/droplet (5 copies lambda DNA per droplet) with Evagreen dye. (b) Time-dependent appearance of the fluorescence signal during compartmentalized amplification of the denatured lambda DNA (input concentration 54 ag/droplet (1 copy lamda DNA per droplet) and 265 ag/droplet). All data are presented as averaged intensities of fluorescent positive droplets measured with SEM, and 100 droplets were analyzed at each time point.</p

Evaluation of amplification bias of droplet MDA.

<p>Distributions of sequencing coverage of MDA products from single <i>Escherichia coli</i> cells (n = 3) were compared between in-tube MDA (left column) and droplet MDA (right column). Each graph shows the results of independent reactions. The averaged sequencing coverages were calculated from raw sequencing reads that mapped to with <i>E</i>. <i>coli</i> reference genome within 1-kb windows. Sequencing reads were normalized to 60× sequencing effort in each experiment.</p

Monodisperse Picoliter Droplets for Low-Bias and Contamination-Free Reactions in Single-Cell Whole Genome Amplification

<div><p>Whole genome amplification (WGA) is essential for obtaining genome sequences from single bacterial cells because the quantity of template DNA contained in a single cell is very low. Multiple displacement amplification (MDA), using Phi29 DNA polymerase and random primers, is the most widely used method for single-cell WGA. However, single-cell MDA usually results in uneven genome coverage because of amplification bias, background amplification of contaminating DNA, and formation of chimeras by linking of non-contiguous chromosomal regions. Here, we present a novel MDA method, termed droplet MDA, that minimizes amplification bias and amplification of contaminants by using picoliter-sized droplets for compartmentalized WGA reactions. Extracted DNA fragments from a lysed cell in MDA mixture are divided into 10⁵ droplets (67 pL) within minutes via flow through simple microfluidic channels. Compartmentalized genome fragments can be individually amplified in these droplets without the risk of encounter with reagent-borne or environmental contaminants. Following quality assessment of WGA products from single <i>Escherichia coli</i> cells, we showed that droplet MDA minimized unexpected amplification and improved the percentage of genome recovery from 59% to 89%. Our results demonstrate that microfluidic-generated droplets show potential as an efficient tool for effective amplification of low-input DNA for single-cell genomics and greatly reduce the cost and labor investment required for determination of nearly complete genome sequences of uncultured bacteria from environmental samples.</p></div

Microfluidic Device with Chemical Gradient for Single-Cell Cytotoxicity Assays

Here, we report the fabrication of a chemical gradient microfluidic device for single-cell cytotoxicity assays. This device consists of a microfluidic chemical gradient generator and a microcavity array that enables entrapment of cells with high efficiency at 88 ± 6% of the loaded cells. A 2-fold logarithmic chemical gradient generator that is capable of generating a serial 2-fold gradient was designed and then integrated with the microcavity array. High density single-cell entrapment was demonstrated in the device without cell damage, which was performed in 30 s. Finally, we validated the feasibility of this device to perform cytotoxicity assays by exposing cells to potassium cyanide (0–100 μM KCN). The device captured images of 4000 single cells affected by 6 concentrations of KCN and determined cell viability by counting the effected cells. Image scanning of the microcavity array was completed within 10 min using a 10× objective lens and a motorized stage. Aligning cells on the microcavity array eases cell counting, observation, imaging, and evaluation of singular cells. Thus, this platform was able to determine the cytotoxicity of chemicals at a single-cell level, as well as trace the cytotoxicity over time. This device and method will be useful for cytotoxicity analysis and basic biomedical research

Amplicon yields by in-tube MDA and droplet MDA.

<p>No template control (NTC), 1 and 10 <i>E</i>. <i>coli</i> cells were used as start material. In the droplet MDA, lysed cells were pumped into the droplet generators and genome DNA fragments were randomly encapsulated into picoliter droplets consist of MDA mixture (67 pL per droplet, total 1.5× 10⁵ droplets). After 180 min of MDA reaction, the yields were evaluated following droplet breaking and amplicon purification. A total of 10 μL of MDA mixture was used in both droplet MDA and in-tube MDA reactions.</p