393 research outputs found
Rancangbangunprototype Panel Surya Sebagai Alat Pengusir Hama Burung
There are many ways which can be done by farmers to repel the bird pests, one of them is by using ultra sonic wave (Parcaya, 2008). Among the farmers there are some methods which are used to repel this bird pest such as by making “orang-orangan” (puppet), banners, ringing cans, putting plastic bags ,catapult and even using air rifle. By means of this bird pest repelling device using ultra sonic wave, it will be benefit for the farmers to repel the bird pest. This device consists of several series electronic, such as solar panel, series of battery charger controller , storage batteries, series of light sensor, series of amplifier/intensifier laser IC 555 and series of ultrasonic sensor. The degree of influence of sparrow pest was decreasing by 95%. The method applied for 4 stages, namely collecting data, device design, device construction and device testing/experiment. The result of this research is solar panel prototype design as a bird pest repelling device innovation which is useful for farmers to ease the jobs
Comparison of global and local features for author's identification by using geometrical and zoning methods
Identification analysis for author's handwriting image in forensic investigation is still an important research area in this current big data era. Images feature extraction can lead to an issue of high dimensionality of data. The process of feature extraction is the most crucial process in author's identification. It is important to choose the best method to represent the image. This study compared two feature extraction methods, namely Higher-Order United Moment Invariant (HUMI) and the Edge-based Directional (ED) method that construct the Global and Local Features respectively. The additional process of discretization was implemented before the training and testing phase to represent the generalized features for the classifier models. This process induced a better performance accuracy for both methods where the discretized Local Features achieved 99.95% accuracy rate that slightly outperforms the discretized Global Features with only 99.91%
Single class classifier using FMCD based non-metric distance for timber defect detection
In this work, we propose a robust Mahalanobis one class classifier with Fast Minimum Covariance Determinant estimator (MC-FMCD) for species independent timber defect detection. Having known in timber inspection research that there is a lack of defect samples compared to defect-free samples (imbalanced data), this unsupervised approach applies outlier detection concept with no training samples required. We employ a non-segmenting approach where a timber image will be divided into non-overlapping local regions and the statistical texture features will then be extracted from each of the region. The defect detection works by calculating the Mahalanobis distance (MD) between the features and the distribution average estimate. The distance distribution is approximated using chi-square distribution to determine outlier (defects). The approach is further improved by proposing a robust distribution estimator derived from FMCD algorithm which enhances the defect detection performance. The MC-FMCD is found to perform well in detecting various types of defects across various defect ratios and over multiple timber species. However, blue stain evidently shows poor performance consistently across all timber species. Moreover, the MC-FMCD performs significantly better than the classical MD which confirms that using the robust estimator clearly improved the timber defect detection over using the conventional mean as the average estimator
Graphene-protected copper and silver plasmonics
Plasmonics has established itself as a branch of physics which promises to
revolutionize data processing, improve photovoltaics, increase sensitivity of
bio-detection. A widespread use of plasmonic devices is notably hindered (in
addition to high losses) by the absence of stable and inexpensive metal films
suitable for plasmonic applications. This may seem surprising given the number
of metal compounds to choose from. Unfortunately, most of them either exhibit a
strong damping of surface plasmons or easily oxidize and corrode. To this end,
there has been continuous search for alternative plasmonic materials that are,
unlike gold, the current metal of choice in plasmonics, compatible with
complementary metal oxide semiconductor technology. Here we show that copper
and silver protected by graphene are viable candidates. Copper films covered
with one to a few graphene layers show excellent plasmonics characteristics
surpassing those of gold films. They can be used to fabricate plasmonic devices
and survive for at least a year, even in wet and corroding conditions. As a
proof of concept, we use the graphene-protected copper to demonstrate
dielectric loaded plasmonic waveguides and test sensitivity of surface plasmon
resonances. Our results are likely to initiate a wide use of graphene-protected
plasmonics.Comment: 22 pages, 5 figure
Atomically thin boron nitride: a tunnelling barrier for graphene devices
We investigate the electronic properties of heterostructures based on
ultrathin hexagonal boron nitride (h-BN) crystalline layers sandwiched between
two layers of graphene as well as other conducting materials (graphite, gold).
The tunnel conductance depends exponentially on the number of h-BN atomic
layers, down to a monolayer thickness. Exponential behaviour of I-V
characteristics for graphene/BN/graphene and graphite/BN/graphite devices is
determined mainly by the changes in the density of states with bias voltage in
the electrodes. Conductive atomic force microscopy scans across h-BN terraces
of different thickness reveal a high level of uniformity in the tunnel current.
Our results demonstrate that atomically thin h-BN acts as a defect-free
dielectric with a high breakdown field; it offers great potential for
applications in tunnel devices and in field-effect transistors with a high
carrier density in the conducting channel.Comment: 7 pages, 5 figure
Klebsiella pneumoniae is able to trigger epithelial-mesenchymal transition process in cultured airway epithelial cells
The ability of some bacterial pathogens to activate Epithelial-Mesenchymal Transition normally is a consequence of the persistence of a local chronic inflammatory response or depends on a direct interaction of the pathogens with the host epithelial cells. In this study we monitored the abilities of the K. pneumoniae to activate the expression of genes related to EMT-like processes and the occurrence of phenotypic changes in airway epithelial cells during the early steps of cell infection. We describe changes in the production of intracellular reactive oxygen species and increased HIF-1α mRNA expression in cells exposed to K. pneumoniae infection. We also describe the upregulation of a set of transcription factors implicated in the EMT processes, such as Twist, Snail and ZEB, indicating that the morphological changes of epithelial cells already appreciable after few hours from the K. pneumoniae infection are tightly regulated by the activation of transcriptional pathways, driving epithelial cells to EMT. These effects appear to be effectively counteracted by resveratrol, an antioxidant that is able to exert a sustained scavenging of the intracellular ROS. This is the first report indicating that strains of K. pneumoniae may promote EMT-like programs through direct interaction with epithelial cells without the involvement of inflammatory cells
Detrimental effects of tropisetron on permanent ischemic stroke in the rat
<p>Abstract</p> <p>Background</p> <p>Recent <it>in vitro </it>evidence indicates that blockade of 5-hydroxytryptamine (5-HT) receptor 3 (5-HT<sub>3</sub>) is able to confer protection in different models of neuronal injury. The purpose of the present study was to investigate the effect of tropisetron, a 5-HT<sub>3 </sub>receptor antagonist, on infarct size and neurological score in a model of ischemic stroke induced by permanent middle cerebral artery occlusion (pMCAO) in the rat.</p> <p>Methods</p> <p>Two different doses of tropisetron (5 and 10 mg/kg) or vehicle were administered intraperitoneally 30 min before pMCAO. Neurological deficit scores, mortality rate and infarct volume were determined 24 h after permanent focal cerebral ischemia.</p> <p>Results</p> <p>Tropisetron failed to reduce cerebral infarction. Animals receiving tropisetron showed a significant increase (p < 0.05) in neurological deficits and mortality rate.</p> <p>Conclusion</p> <p>Data from this study indicate that blockade of 5-HT<sub>3 </sub>receptors with tropisetron worsens ischemic brain injury induced by pMCAO. These findings could have important clinical implications. Patients taking tropisetron, and possibly other 5-HT<sub>3 </sub>antagonists, could potentially have a worse outcome following a brain infarct.</p
Genetic variation in the TLL1 gene is not associated with fibrosis in patients with metabolic associated fatty liver disease
Metabolic associated fatty liver disease (MAFLD) is the most prevalent liver disease in Western nations, with high heritability. A recent study of Japanese patients with the disease suggested that TLL1 rs17047200 is associated with fibrosis; whether a similar association is observed in Caucasian patients with MAFLD is unknown. We investigated the association of the TLL1 rs17047200 polymorphism with liver fibrosis in a cohort of Caucasian patients with MAFLD (n = 728). We also investigated whether TLL1 expression is altered during liver injury in humans, in murine models of fibrosis, and in in-vitro. While TLL1 expression is upregulated in the liver of humans with MAFLD and in mice, the rs17047200 variant was not associated with fibrosis or any other histological features, or with hepatic TLL1 expression. In conclusion, the TLL1 rs17047200 variant is not a risk variant for fibrosis in Caucasian patients with MAFLD. However, TLL1 could be involved in the pathogenesis of liver fibrosis
- …