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This study investigated tenth grade Bhutanese students’ understanding of the law of mechanical energy conservation. A low-cost hands-on model developed using locally available materials designed as an integral part of a guided inquiry laboratory was used as intervention. A single-group pretest-posttest research design was employed. The instruments used to explore the students’ conceptual understanding and views and attitudes were 13 two-tier multiple-choice items and 20 close-ended Likert-based items, respectively. The study also examined the students’ views and attitudes toward a guided inquiry laboratory and the effectiveness of a hands-on model through a semi-structured interview protocol. The data was analysed by calculating the mean, standard deviation, and t-test. The paired-sample t-test indicated a significant enhancement of students’ conceptual understanding due to the intervention of the guided inquiry laboratory from pretest (M=12.59, SD=3.28) to posttest [M=21.39, SD=3.07), t(99) = – 52.14, p

MinD proteins play important roles during cell division process. These proteins show significant characteristics of periodic pole-to-pole propagation along the cell length. The characterizations of these protein behaviors are required to be determined accurately. Usually by using a fluorescent technique, visual motion of proteins in the cell could possibly be made and observed through a CCD. Due to the nature of low intensity of these proteins, the images obtained from the CCD camera were required to subject to noise interference and as a result digital image processing was also required. In this paper, several techniques were tried to facilitated improve the image quality. From our finding, the fluorescent technique could affect the intensity fading of the protein detected, but not to the numbers of the proteins in the cell.

The research was conducted to understand the diversity of microbial communities in the rice cultivars KDM 105 in the rice fields at Sanamchaikate, Chachoengsao Province. The culturing bacterial community in paddy soil before planting, during the planting and sowing of rice, and after rice collection as well as isolation of free nitrogen fixing bacteria under aerobic and anaerobic conditions were identified by molecular comparision of 16S small subunit rRNA genes as well as species diversity and their richness by Most Probable Number (MPN) method. Culturable bacterial isolates in the soil around the roots of rice varieties were determined for their physical appearances on the solid culture (Plate culturing method) and the microscopic observation under light microscope. It was found that bacteria in the paddy soil complemented with organic fertilizers and no pesticide application for over five years had a pH range from 5.2 to 5.5 cultivated jasmine rice, 8-9 log Units of free N2-fixing bacteria near the roots compared with those in other area having 4-5 log Units. Most of them were identified to be Pseudomonas sp. Microbacterium sp. Bacillus sp. Stenotrophomonas sp. and Burkholderia sp., by homology comparison of 16S rDNA gene at 98, 97, 99, 99.5, and 99%, respectively. This research revealed the recognizable complex and change in soil bacteria presented in paddy ecosystem. In any critical change of to the soil, the study of microbial diversity, compositions and their richness can be further useful for indicating proper soil management.

Since the green chemistry strategy of the use of biological process is well known for its safe, easy, nontoxic, biocompatible and especially environmental friendly to all users. Recently, more nanomaterials synthesized by the uses of plants and/ or microorganisms are applied in many areas such as electronics, nanotechnology. Especially they are used to synthesize novel materials with unique properties and purposes. In this study, the researchers aimed to isolate microorganisms with the capability in gold nanoparticles (AuNPs) synthesis from the sources that are from gold management process such as leaching and washing process in gold/ jewelry carving factory. Three isolated genera composed of bacteria, yeasts, fungi synthesizing intracellular AuNOs were obtained and characterized for their species by PCR amplification of rDNA genes and sequence analysis and comparisons. They were Pseudomonas sp., Verticillium sp., Aspergillus sp., and Saccharomyces sp. The factors including pH, temperature, reducing agents, duration of AuNP formation were determined. The predominantly extracellular gold formation as a major criterion for synthesis of AuNPs was also chosen. The obtained isolates can be certain potential in future practical application in harvesting AuNPs from the waste water in most gold carving factory.

Banana flour is one of the main commercial products that could be incorporated into other food products. However, the current processing of banana flour production is not only incompatible to traditional village level; but also difficult to manage for the quality control. In this work, we constructed the low cost banana flour processing machines including dryer and pounder. We also tested our machines by using three conditions of banana cleaning such as salt, vinegar and red lime. The dehydrate banana and flour were characterized by CIE-Lab and particle size analysis. After pneumatic drying at 70oC and 3 hr, we found that vinegar had the whiteness value greater than other conditions. We also found that the flour obtained from vinegar presented the smallest diameter which was approximately 0.017 mm. This particle size diameter corresponds to mesh size No. 20 in ASTM E11:01 standard. These results showed that the characterization protocol of banana flour used to grading the dehydrate banana and flour. Therefore, with our project obtained can be such a high potential approach that can be developed product in household, community in terms of commercial production or community enterprise.

The silver refinery is very important for west management in the jewelry industry. In this work, we proposed the alternative of silver refinery process by using microorganism pathway. We focused on the isolation of microorganism which was found from manufacturing process and forming in gems and jewelry industry. Results showed that the initial silver refinery microorganism performed only in terms of Pseudomonas genus especially in AgNO3 solution. In contrast, Bacillus genus was not clearly effective silver refinery. These results could be the basis information to establish and develop system for silver refinery and/or silver quality improvement with biological process in future.

Min-protein oscillation in Escherichia coli has an essential role in controlling the accurate placement of the cell division septum at the middle-cell zone of the bacteria. This biochemical process has been successfully described by a set of reaction–diffusion equations at the macroscopic level. The lattice Boltzmann method (LBM) has been used to simulate Min-protein oscillation and proved to recover the correct macroscopic equations. In this present work, we studied the effects of LBM boundary conditions (BC) on Min-protein oscillation. The impact of diffusion and reaction dynamics on BCs was also investigated. It was found that the mirror-image BC is a suitable boundary treatment for this Min-protein model. The physical significance of the results is extensively discussed.

In this work, mesoscopic modeling via a computational lattice Boltzmann method (LBM) is used to investigate the flow pattern phenomena and the physical properties of the flow field around one and two square obstacles inside a two-dimensional channel with a fixed blockage ratio, β=1/4, centered inside a 2D channel, for a range of Reynolds numbers (Re) from 1 to 300. The simulation results show that flow patterns can initially exhibit laminar flow at low Re and then make a transition to periodic, unsteady, and, finally, turbulent flow as the Re get higher. Streamlines and velocity profiles and a vortex shedding pattern are observed. The Strouhal numbers are calculated to characterize the shedding frequency and flow dynamics. The effect of the layouts or configurations of the obstacles are also investigated, and the possible connection between the mixing process and the appropriate design of a chemical mixing system is discussed.

We presented an application of the Lattice Boltzmann method (LBM) to study the dynamics of Min proteins oscillations in Escherichia coli. The oscillations involve MinC, MinD and MinE proteins, which are required for proper placement of the division septum in the middle of a bacterial cell. Here, the LBM is applied to a set of the deterministic reaction diffusion equations which describes the dynamics of the Min proteins. This determines the midcell division plane at the cellular level. We specifically use the LBM to study the dynamic pole-to-pole oscillations of the Min proteins in two dimensions. We observed that Min proteins' pattern formation depends on the cell's shape. The LBM numerical results are in good agreement with previous findings, using other methods and agree qualitatively well with experimental results. Our results indicate that the LBM can be an alternative computational tool for simulating the dynamics of these Min protein systems and possibly for the study of complex biological systems which are described by reaction-diffusion equations. Moreover, these findings suggest that LBM could also be useful for the investigation of possible evolutionary connection between the cell's shape and cell division of E. coli. The results show that the oscillatory pattern of Min protein is the most consistent with experimental results when the dimension of the cell is 1 x 2. This suggests that as the cell's shape is close to being a square, the oscillatory pattern no longer places the cell division of E. coli at the proper location. These findings may have a significant implication on why, by natural selection, E. coli is maintained in a rod shape or bacillus form.

The dynamics of MinD protein has been recognized as playing an important role in the accurate positioning of the septum during cell division. In this work, spot tracking technique (STT) was applied to track the motion and quantitatively characterize the dynamic behavior of green fluorescent protein-labeled MinD (GFP-MinD) in an Escherichia coli system. We investigated MinD dynamics on the level of particle ensemble or cluster focusing on the position and motion of the maximum in the spatial distribution of MinD proteins. The main results are twofold: (i) a demonstration of how STT could be an acceptable tool for MinD dynamics studies; and (ii) quantitative findings with parametric and non-parametric analyses. Specifically, experimental data monitored from the dividing E. coli cells (typically 4.98 ± 0.75 µm in length) has demonstrated a fast oscillation of the MinD protein between the two poles, with an average period of 54.6 ± 8.6 s. Observations of the oscillating trajectory and velocity show a trapping or localized behavior of MinD around the polar zone, with average localization velocity of 0.29 ± 0.06 µm/s; and flight switching was observed at the pole-to-pole leading edge, with an average switching velocity of 2.95 ± 0.31 µm/s. Subdiffusive motion of MinD proteins at the polar zone was found and investigated with the dynamic exponent, α of 0.34 ± 0.16. To compare with the Gaussian-based analysis, non-parametric statistical analysis and noise consideration were also performed.

The dynamics of MinD proteins have been acknowledged as playing a central role in accurate cell division. In our study, a spot tracking technique (STT) was applied to track motion and quantitatively characterize the dynamic behavior of MinD proteins on the level of particle cluster in Escherichia coli. We focused on the time and spatial distribution of MinD proteins. With the STT technique, the main quantitative results are twofold: (i) dynamic local and global pattern formations and (ii) energy landscape. The overall MinD cluster motion is governed by two dynamical time scales, namely the (slow) trapping time (∼26 s) that appears at the cell poles, and the (fast) switching time (∼1-2 s) which emerges between the cell poles. MinD cluster motion at the polar zones performs subdiffusion. The energy landscape is found to be two wells and one barrier. These energy landscape results are to relate with the memory effect of GFP-MinD cluster motion, measuring the PSD exponent approximately 1.57 (α ∼ 0.57) corresponding to the estimated potential depth U0 ∼ 1.75kBT .