663 research outputs found
On the stabilization of ion sputtered surfaces
The classical theory of ion beam sputtering predicts the instability of a
flat surface to uniform ion irradiation at any incidence angle. We relax the
assumption of the classical theory that the average surface erosion rate is
determined by a Gaussian response function representing the effect of the
collision cascade and consider the surface dynamics for other
physically-motivated response functions. We show that although instability of
flat surfaces at any beam angle results from all Gaussian and a wide class of
non-Gaussian erosive response functions, there exist classes of modifications
to the response that can have a dramatic effect. In contrast to the classical
theory, these types of response render the flat surface linearly stable, while
imperceptibly modifying the predicted sputter yield vs. incidence angle. We
discuss the possibility that such corrections underlie recent reports of a
``window of stability'' of ion-bombarded surfaces at a range of beam angles for
certain ion and surface types, and describe some characteristic aspects of
pattern evolution near the transition from unstable to stable dynamics. We
point out that careful analysis of the transition regime may provide valuable
tests for the consistency of any theory of pattern formation on ion sputtered
surfaces
Rjasama Fred Hollows Foundations (Fhf) Dengan Tilganga Institue of Ophthalmology (Tio) Dalam Mengatasi Masalah Kebutaan Di Nepal Tahun 2011 â 2014
This research will explain about cooperation between two inter non-governmental organinization named Fred Hollows Foundations (FHF) from Australia and Tilganga Institute of Ophthalmology(TIO) from Nepal. As one of the poorest country in South Asian, desease that causing blindness. Geographical conditions which are in southern Nepal Himalaya make this country has a low level of eye health. This is due to the difficulty of patients to gain access to public services which are mostly located in the capital of Nepal, Kathmandu. FHF works together with TIO to carry out eye health care program such as OMEC (Outreach Microsurgical Eye Camp), Geta Eye Hospital, Training and Infrastructure Development, Advocacy.Sources were obtained through literature revivew from books, journals, reports, and internet to explain FHF and TIO programs. The writer using pluralism as a perspective and cooperation theory as a theory.The survey of blindness in Nepal has been done twice in 1981 and 2010. This research describe cooperation between FHF dan TIO in 2011-2014 to ending blindness after the last survey and see the results of cooperation on the level of blindness in Nepal
PROSES PEMBUATAN CEKAM PADA PIPE PLASMA CUTTING
Tujuan pembuatan cekam adalah mengetahui: (1) bahan yang digunakan;
(2) mesin dan alat yang digunakan; (3) urutan pembuatan cekam pipe plasma
cutting; (4) fungsi cekam pipe plasma cutting.
Metode yang digunakan dalam pembuatan cekam pipe plasma cutting yaitu:
(1) menentukan bahan yang akan digunakan. (2) memilih alat dan mesin apa saja
yang digunakan. (3) langkahâlangkah proses pembuatan cekam. (4) melakukan uji
fungsi rangka pipe plasma cutting.
Cekam pipe plasma cutting menggunakan material baja hollow St 37
dengan spesifikasi 30x50x1 mm, baja hollow St 37 dengan spesifikasi 60x30x3
mm, plat besi 300x111x5 mm, plat besi dengan diameter Ă R132x5, besi siku 30x2,
plat besi 100x250x5, pipa Ă25x1, poros ulir m15x2, besi pejal Ă16 . Dimensi
cekam adalah panjang 264 mm, lebar 244 mm, tinggi 305 mm. (1) Langkah-langkah
proses pembuatan cekam pipe plasma cutting diawali dengan menandai dan
mekukis benda yang akan dipotong. (2) Pemotongan menggunakan gerinda potong
dan gergaji tangan, sedangkan perakitan dilakukan menggunakan las MIG. (3)
Proses finishing meliputi pengamplasan dan pendempulan. (4) Hasilnya cekam
dapat menahan getaran dengan baik serta dapat mencekamp pipa yang akan di
potong dengan bai
Free radical scavenging and elastase inhibitory activity of different extracts of Leucas aspera (Willd.) Link- An in vitro study
61-67Leucas aspera (Willd.) Link has been used for curing various ailments including skin disease in traditional medicine for decades. The aim of the study was to evaluate the in vitro antioxidant potential and anti-elastase activity of L. aspera (Willd.) Link. The hexane, ethyl acetate, acetone and ethanol extracts were prepared using the Soxhlet extraction method. The phytochemical analysis, in vitro free radical scavenging, and anti-elastase activities, were conducted. The total phenol and flavonoids compounds were found to be significantly high for the hexane extract and the ethyl acetate extract respectively. In vitro antioxidant assays like percentage reducing power, DPPH radical scavenging activity, the total antioxidant capacity by FRAP assay, revealed that the acetone extract of the plant L. aspera possesses significantly the highest activity. The anti elastase assay revealed that all the extracts possess elastase inhibitory activity and the hexane extract possessed significantly highest activity with IC50 of 247.42 ”g/mL, at a significant level (α) 0.05. The present result supports the traditional use of L. aspera
Free radical scavenging and elastase inhibitory activity of different extracts of Leucas aspera (Willd.) Link- An in vitro study
Leucas aspera (Willd.) Link has been used for curing various ailments including skin disease in traditional medicine for decades. The aim of the study was to evaluate the in vitro antioxidant potential and anti-elastase activity of L. aspera (Willd.) Link. The hexane, ethyl acetate, acetone and ethanol extracts were prepared using the Soxhlet extraction method. The phytochemical analysis, in vitro free radical scavenging, and anti-elastase activities, were conducted. The total phenol and flavonoids compounds were found to be significantly high for the hexane extract and the ethyl acetate extract respectively. In vitro antioxidant assays like percentage reducing power, DPPH radical scavenging activity, the total antioxidant capacity by FRAP assay, revealed that the acetone extract of the plant L. aspera possesses significantly the highest activity. The anti elastase assay revealed that all the extracts possess elastase inhibitory activity and the hexane extract possessed significantly highest activity with IC50 of 247.42 ”g/mL, at a significant level (α) <0.05. The present result supports the traditional use of L. aspera
Vascular Endothelial Cells Produce Soluble Factors That Mediate the Recovery of Human Hematopoietic Stem Cells after Radiation Injury
AbstractThe risk of terrorism with nuclear or radiologic weapons is considered to be high over the coming decade. Ionizing radiation can cause a spectrum of hematologic toxicities, from mild myelosuppression to myeloablation and death. However, the potential regenerative capacity of human hematopoietic stem cells (HSCs) after radiation injury has not been well characterized. In this study, we sought to characterize the effects of ionizing radiation on human HSCs and to determine whether signals from vascular endothelial cells could promote the repair of irradiated HSCs. Exposure of human bone marrow CD34+ cells to 400 cGy caused a precipitous decline in hematopoietic progenitor cell content and primitive cells capable of repopulating nonobese diabetic/severe combined immunodeficient mice (SCID-repopulating cells), which was not retrievable via treatment with cytokines. Conversely, culture of 400 cGyâirradiated bone marrow CD34+ cells with endothelial cells under noncontact conditions supported the differential recovery of both viable progenitor cells and primitive SCID-repopulating cells. These data illustrate that vascular endothelial cells produce soluble factors that promote the repair and functional recovery of HSCs after radiation injury and suggest that novel factors with radiotherapeutic potential can be identified within this milieu
Short KIR Haplotypes in Pygmy Chimpanzee (Bonobo) Resemble the Conserved Framework of Diverse Human KIR Haplotypes
Some pygmy chimpanzees (also called Bonobos) give much simpler patterns of hybridization on Southern blotting with killer cell immunoglobulin-like receptor (KIR) cDNA probes than do either humans or common chimpanzees. Characterization of KIRs from pygmy chimpanzees having simple and complex banding patterns identified nine different KIRs, representing seven genes. Five of these genes have orthologs in the common chimpanzee, and three of them (KIRCI, KIR2DL4, and KIR2DL5) also have human orthologs. The remaining two genes are KIR3D paralogous to the human and common chimpanzee major histocompatibility complex Aâ and/or -Bâspecific KIRs. Within a pygmy chimpanzee family, KIR haplotypes were defined. Simple patterns on Southern blot were due to inheritance of âshortâ KIR haplotypes containing only three KIR genes, KIRCI, KIR2DL4, and KIR3D, each of which represents one of the three major KIR lineages. These three genes in pygmy chimpanzees or their corresponding genes in humans and common chimpanzees form the conserved âframeworkâ common to all KIR haplotypes in these species and upon which haplotypic diversity is built. The fecundity and health of individual pygmy chimpanzees who are homozygotes for short KIR haplotypes attest to the viability of short KIR haplotypes, indicating that they can provide minimal, essential KIRs for the natural killer and T cells of the hominoid immune system
Transcriptomic Analysis of the Pistacia vera (L.) Fruits Enable the Identification of Genes and Hormone-Related Gene Linked to Inflorescence Bud Abscission
Pistacia vera (L.) is an alternate bearing species. The tree produces axillary inflorescence buds every year. Still, they abscise in âONâ overloaded shoots, causing a limited production in the following âOFFâ year, causing a significant and unfavorable production fluctuation. In this work, we carried out de novo discovery and transcriptomic analysis in fruits of âONâ and âOFFâ shoots of the cultivar Bianca. We also investigated whether the fruit signaling pathway and hormone biosynthesis directly or indirectly linked to the premature fall of the inflorescence buds causing alternate bearing. We identified 1536 differentially expressed genes (DEGs) in fruits of âONâ vs. âOFFâ shoots, which are involved primarily in sugar metabolism, plant hormone pathways and transcription factors. The premature bud abscission linked to the phenomenon is attributable to a lack of nutrients (primarily sugar) and the possible competition between the same branchesâ sinks (fruits vs. inflorescence buds). Hormone pathways are involved as a response to signals degradation and remobilization of carbon and nutrients due to the strengthening of the developing embryos. Genes of the secondary metabolism and transcription factors are also involved in tailoring the individual branches response to the nutritional stress and sink competition. Crosstalk among sugar and various hormone-related genes, e.g., ethylene, auxin, ABA and cytokinin, were determined. The discovery of putative biomarkers like callose synthase 5, trehalose-6-phosphate synthase, NAD(P)-linked oxidoreductase and MIOX2, Jasmonate, and salicylic acid-related genes can help to design precision farming practices to mitigate the alternate bearing phenomenon to increase farming profitability. The aim of the analysis is to provide insight into the gene expression profiling of the fate of âONâ and âOFFâ fruits associated with the alternate bearing in the pistachio
Peer-to-Peer Secure Multi-Party Numerical Computation Facing Malicious Adversaries
We propose an efficient framework for enabling secure multi-party numerical
computations in a Peer-to-Peer network. This problem arises in a range of
applications such as collaborative filtering, distributed computation of trust
and reputation, monitoring and other tasks, where the computing nodes is
expected to preserve the privacy of their inputs while performing a joint
computation of a certain function. Although there is a rich literature in the
field of distributed systems security concerning secure multi-party
computation, in practice it is hard to deploy those methods in very large scale
Peer-to-Peer networks. In this work, we try to bridge the gap between
theoretical algorithms in the security domain, and a practical Peer-to-Peer
deployment.
We consider two security models. The first is the semi-honest model where
peers correctly follow the protocol, but try to reveal private information. We
provide three possible schemes for secure multi-party numerical computation for
this model and identify a single light-weight scheme which outperforms the
others. Using extensive simulation results over real Internet topologies, we
demonstrate that our scheme is scalable to very large networks, with up to
millions of nodes. The second model we consider is the malicious peers model,
where peers can behave arbitrarily, deliberately trying to affect the results
of the computation as well as compromising the privacy of other peers. For this
model we provide a fourth scheme to defend the execution of the computation
against the malicious peers. The proposed scheme has a higher complexity
relative to the semi-honest model. Overall, we provide the Peer-to-Peer network
designer a set of tools to choose from, based on the desired level of security.Comment: Submitted to Peer-to-Peer Networking and Applications Journal (PPNA)
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