475 research outputs found
Interlocking Shish-Kebab morphology in polybutene-1
The aim of this research was to explore the effect of shear-controlled orientation injection molding (SCORIM) on polybutene-1 (PB-1). This article describes the methods and processing conditions used for injection molding and discusses the properties of the moldings. Both conventional and SCORIM have been used for the production of moldings. SCORIM is based on the application of specific macroscopic shears to a solidifying melt that facilitates enhanced molecular alignment. The effect of the process was investigated by performing mechanical tests, X-ray studies, differential scanning calorimetric studies, polarized light microscopy, and atomic force microscopy (AFM). Moldings exhibited an improved mechanical performance as compared with conventional moldings. Young's modulus was increased over twofold, and the impact energy was enhanced by 60%. The improvement in mechanical performance was combined with an increase in crystallinity and enhanced molecular orientation. The application of SCORIM also favored the formation of the stable Form I' in PB-1. The formation of interlocking shish-kebab morphology following the application of SCORIM was observed in the AFM studies. Relationships between the mechanical properties of PB-1 and the micromorphologies formed during processing are demonstrated
Effects of disorder in location and size of fence barriers on molecular motion in cell membranes
The effect of disorder in the energetic heights and in the physical locations
of fence barriers encountered by transmembrane molecules such as proteins and
lipids in their motion in cell membranes is studied theoretically. The
investigation takes as its starting point a recent analysis of a periodic
system with constant distances between barriers and constant values of barrier
heights, and employs effective medium theory to treat the disorder. The
calculations make possible, in principle, the extraction of confinement
parameters such as mean compartment sizes and mean intercompartmental
transition rates from experimentally reported published observations. The
analysis should be helpful both as an unusual application of effective medium
theory and as an investigation of observed molecular movements in cell
membranes.Comment: 9 pages, 5 figure
Penggunaan Ekstrak Buah Hutung (Barringtonia Asiatika) untuk Mengendalikan Hama Maruca Testulalis Penggerek Polong pada Kacang Panjang
The use of synthetic chemicals to control plant pest should to be limited by utilizing natural products so that environmental contamination can be reduced and crop yields are safe to eat. The aim of this research is to get the effective concentration and application time of hutung fruit (Barringtonia asiatika) extract to control Maruca testulalis pod borer on long bean. The experiments design was complety randomized block design with treatments of 5% extract of hutung fruit with interval of time of two days application, 5% extract of nutmeg with time interval of three days application, 10% extract of nutmeg with time interval of two days application, 10% fruit extract hutung with a three-day application time interval. Two control treatments were 0.1% Decis insecticide with a three-day application time interval three replications and without any treatment. The result showed that 10% hutung fruit extract with two days application time interval was the best treatment and could decrease the intensity of Maruca testulalis pest borer attack on long bean up to 39,14%
Control of Damping Off and Increased Growth of Tomato Seeds by Utilizing Trichoderma Harzianum Based on Solid Organic Materials
Low soil fertility and the presence of damping off disease which is a inhibiting factor in the nursery of tomato plants. This can be overcome by utilizing the biological agent Trichoderma harzianum based on solid organic matter (Trichocompost). The aim of the study was to determine the effect of giving Trichocompost and obtain the optimal Trichocompos dose to reduce the intensity of damping off disease and increase the growth of tomato seedlings. The treatments tried were Trichocompos with doses of 20, 40 and 60 tons/ha, designed using a complete randomized design with 10 replications. The plant response observed was the intensity of the disease; height, fresh weight and dry weight of canopy; length, fresh weight and root dry weight. The results showed that the monitoring of Trichocompost can reduce the intensity of damping off disease to 54.80% and increase the growth of tomato seedlings. The recommended Trichocompos dosage is 60 tons/ha or as much as 30 g/1 kg of soil. The results of this study can be used to increase agricultural production and also a solution in an environmentally friendly and sustainable farming system
Molecular motion in cell membranes: analytic study of fence-hindered random walks
A theoretical calculation is presented to describe the confined motion of
transmembrane molecules in cell membranes. The study is analytic, based on
Master equations for the probability of the molecules moving as random walkers,
and leads to explicit usable solutions including expressions for the molecular
mean square displacement and effective diffusion constants. One outcome is a
detailed understanding of the dependence of the time variation of the mean
square displacement on the initial placement of the molecule within the
confined region. How to use the calculations is illustrated by extracting
(confinement) compartment sizes from experimentally reported published
observations from single particle tracking experiments on the diffusion of
gold-tagged G-protein coupled mu-opioid receptors in the normal rat kidney cell
membrane, and by further comparing the analytical results to observations on
the diffusion of phospholipids, also in normal rat kidney cells.Comment: 10 pages, 5 figure
Long term clinical outcomes of brachytherapy, bare-metal stenting, and drug-eluting stenting for de novo and in-stent restenosis lesions: Five year follow-up
Background: We aimed to investigate the effects of brachytherapy, drug-eluting stent (DES)
and bare metal stent (BMS) applications in the treatment of coronary artery disease, on five-
-year clinical outcomes and mortality.
Methods: Two hundred and seventeen patients who were treated in our clinics between
January 2000 and December 2003 with brachytherapy, DES, or BMS for both de novo and in-
-stent restenosis lesions were included in this cohort study. Of these 217 patients, 69 received
brachytherapy, 80 were given BMS and 68 were given DES. The clinical outcomes of the
patients during hospitalization and over a long-term follow-up were evaluated. Cardiovascular
events, revascularizations and mortality rates were compared among the three groups over
a five-year follow-up.
Results: The mean age was 60.1 ± 9.5 years in the brachytherapy group, 55.7 ± 9.2 years in
the BMS group, and 58.9 ± 9.8 years in the DES group (p = 0.44). All-cause mortality rates
were 20 (29%) brachytherapy patients, 22 (27.5%) BMS patients, and four (5.9%) DES
patients (p = 0.01). Cardiovascular event was the cause of death for 14 (20.3%) brachytherapy
patients, 16 (20%) BMS patients and four (5.9%) DES patients (p = 0.001). All-cause
mortality rates were 20 (29%) brachytherapy patients, 22 (27.5%) BMS patients and four
(5.9%) DES patients. All-cause and cardiovascular mortality rates were significantly lower in the
DES group compared to both the BMS and the brachytherapy groups (p = 0.01 and p = 0.001,
respectively).
Conclusions: DES application for in-stent restenosis and de novo lesions was superior to
brachytherapy and BMS application with respect to all-cause and cardiovascular mortalities.
(Cardiol J 2011; 18, 6: 654–661
The nonlinear time-dependent response of isotactic polypropylene
Tensile creep tests, tensile relaxation tests and a tensile test with a
constant rate of strain are performed on injection-molded isotactic
polypropylene at room temperature in the vicinity of the yield point. A
constitutive model is derived for the time-dependent behavior of
semi-crystalline polymers. A polymer is treated as an equivalent network of
chains bridged by permanent junctions. The network is modelled as an ensemble
of passive meso-regions (with affine nodes) and active meso-domains (where
junctions slip with respect to their positions in the bulk medium with various
rates). The distribution of activation energies for sliding in active
meso-regions is described by a random energy model. Adjustable parameters in
the stress--strain relations are found by fitting experimental data. It is
demonstrated that the concentration of active meso-domains monotonically grows
with strain, whereas the average potential energy for sliding of junctions and
the standard deviation of activation energies suffer substantial drops at the
yield point. With reference to the concept of dual population of crystalline
lamellae, these changes in material parameters are attributed to transition
from breakage of subsidiary (thin) lamellae in the sub-yield region to
fragmentation of primary (thick) lamellae in the post-yield region of
deformation.Comment: 29 pages, 12 figure
High-Accuracy X-Ray Diffraction Analysis of Phase Evolution Sequence During Devitrification of Cu50Zr50 Metallic Glass
Real-time high-energy X-ray diffraction (HEXRD) was used to investigate the crystallization kinetics and phase selection sequence for constant-heating-rate devitrification of fully amorphous Cu50Zr50, using heating rates from 10 K/min to 60 K/min (10 °C/min to 60 °C/min). In situ HEXRD patterns were obtained by the constant-rate heating of melt-spun ribbons under synchrotron radiation. High-accuracy phase identification and quantitative assessment of phase fraction evolution though the duration of the observed transformations were performed using a Rietveld refinement method. Results for 10 K/min (10 °C/min) heating show the apparent simultaneous formation of three phases, orthorhombic Cu10Zr7, tetragonal CuZr2 (C11b), and cubic CuZr (B2), at 706 K (433 °C), followed immediately by the dissolution of the CuZr (B2) phase upon continued heating to 789 K (516 °C). Continued heating results in reprecipitation of the CuZr (B2) phase at 1002 K (729 °C), with the material transforming completely to CuZr (B2) by 1045 K (772 °C). The Cu5Zr8 phase, previously reported to be a devitrification product in C50Zr50, was not observed in the present study
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