Top Portions Research Articles

Fabrication and in vitro evaluation of bidirectional release and stability studies of mucoadhesive donut-shaped captopril tablets

Objective: To obtain controlled release of captopril in the stomach, coated, mucoadhesive donut-shaped tablets were designed.Materials and methods: Donut-shaped tablet were made of different ratios of diluents to polymer or combination of polymers by direct compression method. Top and bottom portions of the tablet were coated with water-insoluble polymer followed by mucoadhesive coating. Time of water penetration, measurement of tensile strength, mucoadhesion studies (static ex vivo and ex vivo wash-off) were taken into account for characterization of respective films. In vitro study has been performed at different dissolution mediums. Optimized batches were also prepared by wet granulation. Stability studies of optimized batches have been performed.Results: The results of time of water penetration and tensile strength indicated positive response against water impermeation. Mucoadhesive studies showed that film thickness of 0.12 mm was good for retention of tablet at stomach. At pH 1.2, optimized batch of tablet made with hydroxypropyl methyl cellulose (HPMC) E15 as binder showed 80% w/w drug release within 4–5 h with maximum average release of 97.49% w/w. Similarly, maximum average releases of 96.36% w/w and 95.47% w/w were obtained with nearly same dissolution patterns using combination of HPMC E5 and HPMC E50 and sodium salt of carboxy methyl cellulose (NaCMC) 500–600 cPs instead of HPMC E15. The release profiles in the distilled water and pH 4.5 followed the above pattern except deviation at pH 6.8. Stability studies were not positive for all combinations.Conclusion: Coated, mucoadhesive donut-shaped tablet is good for controlled release of drug in the stomach.

Characterization of gas–solid fluidization: A comparative study of acoustic and pressure signals

The hydrodynamics of fluidized beds strongly influence their operation, but are complicated and chaotic. There are many measurement techniques, but none fully characterizes gas–solid fluidized beds. Acoustic signals from fluidized beds cover a wide frequency spectrum and can be correlated to bed characteristics. Experiments were conducted to study the acoustic signals from ultrasonic transducers mounted on the outer wall of a two-dimensional fluidization column. The acoustic signals were related to bubble behavior in 550 μm glass beads. Simultaneous acoustic and pressure measurements allowed direct comparison of these signals for single bubbles, pairs and chains of bubbles. The envelope of acoustic signals, generated by particle collisions and particle–wall impacts, provided information on the behavior of bubbles. Significant peaks appeared as the top portions of the bubble wakes approached the acoustic sensor. Pressure waves propagated considerably in the horizontal direction, whereas acoustic signals propagated little in the lateral direction, but transmitted forward in the wall in the direction of bubble motion, maintaining the wave profile invariant during transmission. The strong lateral localization of acoustic signals is promising for determining the lateral bubble position in the bed. Acoustic signals provide a potential means of determining such bubble properties as velocity, frequency and volume, with some advantages relative to pressure signals.

Levels of infestation on three different portions of the maize cob by the weevil <i>Sitophilus zeamais</i> (motschulsky)

The maize weevil, Sitophilus zeamais is a major storage pest of maize that causes significant quantitative and qualitative losses to the farmer. The extent of damage caused by S. zeamais to stored maize depends on the initial level of infestation on the field before harvest. The levels ofinfestations on three different portions of maize cob were studied. Maize was planted during the minor planting season (September-December) of 2008. Maize seeds were sown on 9 plots each measuring 7.0 m x 1.5 m. Matured maize cobs were harvested 110 days after emergence. Tencobs were randomly selected from each of the plots, dehusked and cut into three portions: top, middle and bottom and stored separately in sealed plastic containers for 5 weeks. Weevils were counted weekly during the storage period. Percent damaged seeds and numbers of holes on damaged grains were counted for each portion. Percent weight loss due to S. zeamais infestation was calculated for the different maize portions. Weevil infestations were recorded on all the portions 1 week after storage. Large numbers of S. zeamais were recorded on all the portions at the endof the storage period. The middle portion recorded significantly more S. zeamais than the top and bottom portions. Percent damaged seeds; percent weight loss and mean number of holes on damaged seeds did not differ significantly.

Study of age and height wise variability on calorific value and other fuel properties of Eucalyptus hybrid, Acacia auriculaeformis and Casuarina equisetifolia

Abstract The age and height wise variations in the fuel properties (basic density, calorific value, proximate and elemental parameters) of three short rotation forestry species i.e., Eucalyptus hybrid, Acacia auriculaeformis and Casuarina equisetifolia have been investigated. The fuel properties parameters were evaluated from the test samples of different age from 2 to 6 year and the samples obtained from three different height of trees i.e., stump height, diameter at breast height and top. A marginal increase in the calorific value with the age of tree (2–6 years) was found in all the species, the variation being significant in E. hybrid and C. equisetifolia. The basic density values were also found significantly different in E. hybrid and C. equisetifolia at lower ages (2–6 years). However, when the results were analyzed along the tree height, the calorific values were found to decrease along the stem length towards the tree-top in A. auriculaeformis and C. equisetifolia. The ash content in general was found to be higher in the top portions of the trees, and the same was found significantly higher in case of A. auriculaeformis. There was no particular trend observed for volatile matter content and the fixed carbon content with age. The fuel properties of lower age trees were compared with that of a mature tree (20 years of age) of same species. In general, the fuel properties of mature trees were found to be better than trees of lower age.

Abscisic Acid Regulates Inflammation via Ligand-binding Domain-independent Activation of Peroxisome Proliferator-activated Receptor γ

Abscisic acid (ABA) has shown efficacy in the treatment of diabetes and inflammation; however, its molecular targets and the mechanisms of action underlying its immunomodulatory effects remain unclear. This study investigates the role of peroxisome proliferator-activated receptor γ (PPAR γ) and lanthionine synthetase C-like 2 (LANCL2) as molecular targets for ABA. We demonstrate that ABA increases PPAR γ reporter activity in RAW 264.7 macrophages and increases ppar γ expression in vivo, although it does not bind to the ligand-binding domain of PPAR γ. LANCL2 knockdown studies provide evidence that ABA-mediated activation of macrophage PPAR γ is dependent on lancl2 expression. Consistent with the association of LANCL2 with G proteins, we provide evidence that ABA increases cAMP accumulation in immune cells. ABA suppresses LPS-induced prostaglandin E(2) and MCP-1 production via a PPAR γ-dependent mechanism possibly involving activation of PPAR γ and suppression of NF-κB and nuclear factor of activated T cells. LPS challenge studies in PPAR γ-expressing and immune cell-specific PPAR γ null mice demonstrate that ABA down-regulates toll-like receptor 4 expression in macrophages and T cells in vivo through a PPAR γ-dependent mechanism. Global transcriptomic profiling and confirmatory quantitative RT-PCR suggest novel candidate targets and demonstrate that ABA treatment mitigates the effect of LPS on the expression of genes involved in inflammation, metabolism, and cell signaling, in part, through PPAR γ. In conclusion, ABA decreases LPS-mediated inflammation and regulates innate immune responses through a bifurcating pathway involving LANCL2 and an alternative, ligand-binding domain-independent mechanism of PPAR γ activation.

Failure Behaviour of Semantan Bamboo Strips Loaded in Bending and Shear

In this study, the classification of modes of failure, the observation of microscopic failures and the mechanical properties of Semantan bamboo strips were investigated. Specimens were loaded in bending and shear parallel to grain. Specimens were taken from internodes and node parts in bottom, middle and top portions of bamboo culms. From the classification, different modes of failure occurred in different parts of Semantan bamboo culms loaded in bending and shear. From the microscopic observation, the failures occurred in both parenchyma and vascular bundles regions for all classified failure modes from all tests, except for Even Splitting Mode from shear. This mode exhibited failure in parenchyma only, without any failure in vascular bundles regions. The Maximum Stress (σml) values between failure modes for both tests were significantly different. Generally, anatomical behaviour at different culm’s parts had influenced the different modes of failure and microscopic failures of Semantan bamboo strips loaded in bending and shear.

Formation of ultra-smooth 45° micromirror on (1 0 0) silicon with low concentration TMAH and surfactant: Techniques for enlarging the truly 45° portion

This paper describes the fabrication of ultra-smooth 45° micromirrors on (1 0 0) silicon using low concentration tetramethylammonium hydroxide (TMAH) water solution with a new NCW-1002 surfactant, the etching property of which as an effective additive in TMAH is discussed. The formation of the 45° micromirror is investigated by examining the cross-sectional view of the micromirror slope in detail. Results show that only the middle portion of the micromirror is truly at 45° with the (1 0 0) plane, whilst the top and bottom portions of the micromirror deviate from 45°. The non-45° portions of the micro-mirror slope are due to (1) nearly isotropic etching behavior for planes close to (1 0 0) plane for surfactant added low concentration TMAH; (2) diffusion dependent etch effects arising from the overhanging oxide. Two techniques have been developed to extend the truly 45° portion of the micromirror. One technique involves successive removal of the overhanging oxide to effectively extend the truly 45° portion of the slope towards the micromirror top. The other technique involves an additional masking step to recess the non-45° lower portion of the micromirror.

Numerical study of natural convection in a vertical porous annulus with discrete heating

In this paper natural convection flows in a vertical annulus filled with a fluid-saturated porous medium has been investigated when the inner wall is subject to discrete heating. The outer wall is maintained isothermally at a lower temperature, while the top and bottom walls, and the unheated portions of the inner wall are kept adiabatic. Through the Brinkman-extended Darcy equation, the relative importance of discrete heating on natural convection in the porous annulus is examined. An implicit finite difference method has been used to solve the governing equations of the flow system. The analysis is carried out for a wide range of modified Rayleigh and Darcy numbers for different heat source lengths and locations. It is observed that placing of the heater in lower half of the inner wall rather than placing the heater near the top and bottom portions of the inner wall produces maximum heat transfer. The numerical results reveal that an increase in the radius ratio, modified Rayleigh number and Darcy number increases the heat transfer, while the heat transfer decreases with an increase in the length of the heater. The maximum temperature at the heater surface increases with an increase in the heater length, while it decreases when the modified Rayleigh number and Darcy number increases. Further, we find that the size and location of the heater effects the flow intensity and heat transfer rate in the annular cavity.

An Investigation of Bread‐Baking Process in a Pilot‐Scale Electrical Heating Oven Using Computational Fluid Dynamics

A computational fluid dynamics (CFD) model was developed for bread-baking process in a pilot-scale baking oven to find out the effect of hot air distribution and placement of bread on temperature and starch gelatinization index of bread. In this study, product (bread) simulation was carried out with different placements of bread. Simulation results were validated with experimental measurements of bread temperature. This study showed that nonuniform air flow pattern inside the oven cavity leads to uneven temperature distribution. The study with respect to placement of bread showed that baking of bread in upper trays required shorter baking time and gelatinization index compared to those in the bottom tray. The upper tray bread center reached 100 °C at 1200 s, whereas starch gelatinization completed within 900 s, which was the minimum baking index. Moreover, the heat penetration and starch gelatinization were higher along the sides of the bread as compared to the top and bottom portions of the bread.

The effect of host plant species on performance and movement behaviour of the cabbage looper Trichoplusia ni and their potential influences on infection by Autographa californica multiple nucleopolyhedrovirus

1 Cabbage loopers Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae) are serious pests in greenhouses growing tomatoes, cucumbers and bell peppers. A potential microbial control, now in development, is the broad host-range virus Autographa californica multiple nucleopolyhedrovirus (AcMNPV). 2 The relationships between the three host plants and the feeding behaviour, larval movement and performance of cabbage looper larvae that might relate to their interaction with AcMNPV applications were investigated. 3 Larvae reared on cucumber plants consumed approximately ten-fold more leaf area than larvae reared on pepper plants and almost five-fold more than larvae reared on tomato plants. This could influence the amount of AcMNPV consumed if it were used as a microbial spray because increased consumption can be associated with increased probability of infection. Survival from neonate to pupa also varied, with the greatest being on cucumber, followed by tomato and pepper plants. Larvae fed cucumber were approximately four-fold heavier than larvae fed tomato and over 15-fold heavier than larvae fed pepper plants. 4 The distribution of larvae on plants in commercial greenhouses where a single crop was being grown also varied with food plant with 73% being found on the bottom and middle portions of tomato plants and 87% occurring in the top portions of pepper plants. Larvae tended to be distributed on the middle portion of cucumber plants, the lower portion of tomato plants and the top portion of pepper plants. Larval movement did not vary between AcMNPV-infected and uninfected controls. 5 It is predicted that the higher leaf area consumption and location of larvae in the middle portion of cucumber plants may make them more susceptible to viral sprays. Furthermore, given their greater survival than larvae fed tomato and pepper, there may be a greater need for virus applications.

Environmentally friendly technologies to maintain stored paddy rice quality

Exports of processed rice have been increasing every year, as well as legislative restrictions and consumer demand for certified chemical free rice, pressing the rice processing industry to new challenges. The objective of this work was the implementation of a Rice Quality Certification Program. The package includes the association of a rigorous sanitation program and safe environmentally friendly control measures. It was accomplished in a large paddy rice facility with 40 silos during the 2008/09 rice crop. Silo sanitation was done by washing with pressurized water the conveyor belt structure above the silo roof, around the externals walls and thorough aspiration of the aeration system. During silo filling, the lower and top portions of the rice grain were treated with a mixture of diatomaceous earth (DE) and powder deltamethrin. Artificial chilling was applied as soon as the top layer of the grain mass was leveled by insufflating cool air (6 to 8oC) with a large cooling machine through the aeration system. The grain mass temperature stabilized at about 12-14oC, and kept this range of temperature for about 60 d. As the temperature of the grain mass increased, mainly on the top layer, aeration was performed with natural air from the cold fronts during the winter months. After 8 months on storage the rice was free of external insects, as proved by the grain sampling just before processing. For the 2009/10 crop season, the rice quality program will be repeated on 60 silos with few adjustments. Keywords : Chilled aeration, Inert dust, Physical insect control, Rice quality maintenance.

Electromagnetic radiation during plastic deformation under unrestricted quasi-static compression in metals and alloys

Abstract Intermittent electromagnetic radiation (EMR) emissions from metals and alloys during deformation under unrestricted quasi-static compression are reported in this paper. The end surface conditions of the compressing platens, whether lubricated or unlubricated, influence the EMR emission characteristics. The EMR emissions under compression show shape anisotropy. The first EMR emission invariably occurs near the yield. The EMR emission characteristics are also influenced by the crystal structure. During axial compression, dead metal zones formed on the top and bottom portions of the specimens possibly generate a climbing motion of edge dislocations in the radially outward mid-regions. During the climbing motion, these edge dislocations form accelerated electric line dipoles and emit electromagnetic radiation. These EMR emissions can be used to evaluate the degree of damage in metallic components under compression.

Episodic detachment of Martian crustal magnetic fields leading to bulk atmospheric plasma escape

We present an analysis of magnetic field and suprathermal electron measurements from the Mars Global Surveyor (MGS) spacecraft that reveals isolated magnetic structures filled with Martian atmospheric plasma located downstream from strong crustal magnetic fields with respect to the flowing solar wind. The structures are characterized by magnetic field enhancements and rotations characteristic of magnetic flux ropes, and characteristic ionospheric electron energy distributions with angular distributions distinct from surrounding regions. These observations indicate that significant amounts of atmosphere are intermittently being carried away from Mars by a bulk removal process: the top portions of crustal field loops are stretched through interaction with the solar wind and detach via magnetic reconnection. This process occurs frequently and may account for as much as 10% of the total present‐day ion escape from Mars.

Migration of pine wood nematodes in the tissues of Pinus thunbergii

The distribution of pine wood nematodes (Bursaphelenchus xylophilus, PWNs) in Japanese black pine (Pinus thunbergii) tissues was investigated by staining with fluorescein isothiocyanate-conjugated wheat germ agglutinin. After PWNs were inoculated to current-year stems of pine seedlings, their distribution at about 5 cm below the inoculation site was confined only to cortical resin canals 1 day after inoculation, and then spread to other tissues, including resin canals of short branches. When PWNs were inoculated onto cross or tangentially cut surfaces of stem segments, maximal PWN migration speed was estimated to be faster through cortical resin canals and xylem axial resin canals vertically (>6.7 and <2.3 mm/h, respectively) than through cortical tissues both vertically and horizontally (<1.2 and <0.2 mm/h). To examine whether PWNs in cortical resin canals could invade surrounding tissues, segments in which PWNs resided only in cortical resin canals were prepared by removing the top portion 6 h after inoculation. Additional incubation of such segments caused extended PWN distribution to xylem axial resin canals and then to other tissues. A similar experiment with top portions of girdled segments removed 12 h after inoculation also showed extended PWN distribution from xylem axial resin canals and pith to cortical resin canals and then to other tissues. These results provided direct evidence that PWNs have the ability to migrate from cortical resin canals and xylem axial resin canals to other tissues.

Chemical Changes in 15 Year-old Cultivated Acacia Hybrid Oil-Heat Treated “at 180, 220 and 220°C”

The chemical constituents of oil-heat treated cultivated 15 years-old Acacia hybrid were investigated. The logs of A.hybrid were harvested and cut at bottom, middle and top portions and oil-heat treated using organic palm oil attemperatures of 180, 200 and 220°C for the time 30, 60 and 90 minutes. The wood samples were dried and grinded intosawdust, and air-dried again prior to the chemical analysis. Untreated samples were used as controls. The results on theanalysis of the chemical contents in the oil-treated A. hybrid shows some changes occurred when treated from 180 to220°C. The variation occurred in the chemical contents for both the sapwood and heartwood. The holocellulose contents decrease from 71.5 to 63.1% and 73.4 to 64.0% for sapwood and heartwood respectively. The cellulosecontents decreased from 47.1 to 37.7% for the sapwood and 48.9 to 38.1% for heartwood. The hemicellulose content'sincreases from 24.4 to 25.4% in the sapwood and 24.5 to 25.9% for the heartwood. Lignin contents increased 20.8 to24.0% for the sapwood and 22.4 to 24.9% in the heartwood for treatment temperature from 180 to 220°C.

Warpage Mechanism of Thin Embedded LSI Packages

The warpage mechanism of a thin embedded LSI package with a thick Cu plate was investigated for various Cu plate thicknesses. The package warpage increased gradually as the Cu plate was made thinner. Even structures with a balanced Cu and resin layer configuration for the top and bottom portions of the embedded chip showed substantial warpage, especially in the chip region, that was greater than that for an unbalanced layer configuration. This indicates the existence of other warpage factors as well as unbalanced residual stress between the top and bottom of the chip. A `Birth & Death' finite element method simulation showed that the thermal residual stresses induced by the coefficient of thermal expansion mismatch for the LSI chip and embedding resin were concentrated in the resin surrounding the lateral sides of the chip and that the stresses increased with decreasing Cu thickness. The release of these tensile stresses resulted in package warpage.

Volatile Terpenoid Composition of Origanum vulgare L. Derived from Top, Middle and Lower Portions of the Plant Cultivated in Uttarakhand

The essential oil obtained from top-1/3, middle-1/3 and lower-1/3 portions of Origanum vulgare L. cultivated in Kumaon region of western Himalaya was compared for their content and composition. The essential oil content varied from 0.26 % to 0.91 %with the highest in top-1/3. GC and GC-MS analyses enabled to identify 37 components which showed considerable variation in the quantitative composition of the oils. Major components of oils were carvacrol (52.17 % - 66.08 %), γ-terpinene (5.53 % - 24.13 %) and p-cymene (4.17 % - 34.43 %). The concentration of phenolic monoterpenes decreased from top to bottom, whilst the amount of monoterpene hydrocarbons increased in the same direction.

Magnetization scissoring in aluminum/Permalloy microstructures

Induced scissoring of magnetization has been observed in aluminum/Permalloy (Ni81Fe19) thin films upon application of an alternating current. Harmonic analysis of the magnetoresistance indicates that the magnetization in the top and bottom portions of the film can rotate ±20° from the axis along which the current is applied. The opposite angles of rotation, or scissoring, can be explained by internal oersted fields from the current. These oersted fields will rotate the in-plane magnetization of the film in opposite directions through the thickness of the film. Simulation using OOMMF shows a high degree of correlation with the observed data.

Characteristics of a Three-Dimensional Square Jet in the Vicinity of a Free Surface

The characteristics of a turbulent jet issuing from a square cross section nozzle in the vicinity of a free surface are presented. Two-component laser Doppler measurements were obtained at eight stations downstream of the nozzle exit, up to a distance of 27 nozzle widths. The Reynolds number based on the exit condition was 40,000. The proximity of the free surface influence the turbulence levels in the jet. Both confinement effects and axis switching influence the evolution of the velocity profiles downstream of the nozzle. The shear stress profiles indicate the formation of a wider mixing zone in the bottom portion of the jet in regions closer to the nozzle exit. Through quadrant decomposition, ejection, and entraining type events were identified. The magnitudes of the peak shear stress in the various quadrants indicate differences in the turbulence characteristics on the top and bottom portions of the jet. As distinguished in the extreme event plots, there are differences in the magnitudes of the peaks ...

Genome-Wide Analysis of Gene Expression in Primate Taste Buds Reveals Links to Diverse Processes

Efforts to unravel the mechanisms underlying taste sensation (gustation) have largely focused on rodents. Here we present the first comprehensive characterization of gene expression in primate taste buds. Our findings reveal unique new insights into the biology of taste buds. We generated a taste bud gene expression database using laser capture microdissection (LCM) procured fungiform (FG) and circumvallate (CV) taste buds from primates. We also used LCM to collect the top and bottom portions of CV taste buds. Affymetrix genome wide arrays were used to analyze gene expression in all samples. Known taste receptors are preferentially expressed in the top portion of taste buds. Genes associated with the cell cycle and stem cells are preferentially expressed in the bottom portion of taste buds, suggesting that precursor cells are located there. Several chemokines including CXCL14 and CXCL8 are among the highest expressed genes in taste buds, indicating that immune system related processes are active in taste buds. Several genes expressed specifically in endocrine glands including growth hormone releasing hormone and its receptor are also strongly expressed in taste buds, suggesting a link between metabolism and taste. Cell type-specific expression of transcription factors and signaling molecules involved in cell fate, including KIT, reveals the taste bud as an active site of cell regeneration, differentiation, and development. IKBKAP, a gene mutated in familial dysautonomia, a disease that results in loss of taste buds, is expressed in taste cells that communicate with afferent nerve fibers via synaptic transmission. This database highlights the power of LCM coupled with transcriptional profiling to dissect the molecular composition of normal tissues, represents the most comprehensive molecular analysis of primate taste buds to date, and provides a foundation for further studies in diverse aspects of taste biology.