Effects of Cholesterol on the mechanism of fengycin, a biofungicide

Fengycins are a class of antifungal lipopeptides synthesized by the bacteria Bacillus subtilis, commercially available as the primary component of the agricultural fungicide Serenade. They are toxic to fungi, but far less to mammalian cells. One key difference between mammalian and fungal cell membranes is the presence of cholesterol only in the former; recent experimental work showed that the presence of cholesterol reduces fengycin-induced membrane leakage. Since our previous all-atom and coarse-grained simulations suggested that aggregation of membrane-bound fengycin is central to its ability to disrupt membranes, we hypothesized that cholesterol might reduce fengycin aggregation. Here, we test this hypothesis using coarse-grained molecular dynamics simulations, with sampling enhanced via the weighted ensemble method. The results indicate that cholesterol subtly alters the size distribution for fengycin aggregates, limits the lateral range of their membrane disordering, and reduces the ability of aggregates to bend the membrane. Taken together, these phenomena may account for cholesterols' affects on fengycin activity.

Numerical Simulation of Velocity Field around Two Columns of Tandem Piers of the Longitudinal Bridge

This research explores the effects of different spans of two columns of tandem piers on the characteristics of x-velocity near the river bed based on computational fluid dynamics (CFD) simulations. With a span shorter than 27.5D (D is the diameter of piers), the shape and the lateral range of the x-velocity increases with the increase of distance downwards the x-direction. For the area between the tandem piers and the wall, the VRi/VR1 (the ratio of the x-velocity at the i-th row to the x-velocity of the first row in each model) near the wall increases up to 1.26. For the area between the two columns of tandem piers, the profile of VRi/VR1 changes from a “∩-shape” to an “M-shape” in each model. RAVC (average velocity change ratio) of different spans increases gradually and tends to be stable with the increases of the span. The largest RAVC is about −17.66% with a span of 0.52 m. The RMV (the ratio of the maximum x-velocity among piers in each row in different models to the maximum x-velocity of the two piers arranged side by side) of piers in the first row of different models is around 0.95. The RMV becomes 0.82 at the second pier in each model when the span is shorter than 27.5D, and increases to 0.91 if the span is longer than 27.5D. If the span is longer than 27.5D, the RMV of different piers are close to each other from the 2nd pier to the last one.

Layanan Pendidikan Bagi Anak Tunagrahita Dengan Tipe Down Syndrome

One of abnormalities in children in terms of mental retardation is down syndrome. Down syndrome is a mental retardation disorder in which the IQ is below normal average. Children with down syndrome have mental retardation function of intellectuals in the range of middle inability with the lateral range of IQ is 40-45. The cause of down syndrome is the abnormalities of chromosome number 21 which is not properly composed of two chromosomes. In fact, there are three chromosomes (trisomy 21) that cause the children to experience the physical and intellectual malformation. Mental retardation children with down syndrome experience some barriers to achieve the developmental tasks of cognitive, affective, and psychomotor aspects. However, they can still develop a non-academic potency such as taking care of themselves, making friends, and appreciating others’ property rights. Children who grow up with the abnormalities like as down syndrome have the same rights to obtain adequate educational services. Therefore, some educational services programs that can be arranged for the children with mental retardation of down syndrome are classroom-supports and guidance for them through visual and graphic approaches, cues-prompts and scaffolding, technology-based learning, and music-based learning.

Two-Dimensional Modeling of Aluminum-Ion Implantation into 4H-SiC

A two-dimensional model of aluminum-ion implantation into 4H-SiC at moderate doses (1011 to 1013 cm-2) has been developed. The model is based on a Monte-Carlo simulation using a binary-collision approximation. This simulation reveals that iso-concentration contours are independent of the orientation of the masking edge. Lateral range straggling is extracted by expressing the lateral-concentration profiles as a one-dimensional dual-Pearson-distribution function multiplied by a Gauss-distribution function. Compared to vertical straggling, the lateral straggling is found to be more weakly dependent on projected range.