Optimization of Process Parameters of Al-Si Alloy by Centrifugal Casting Technique Using Taguchi Design of Experiments

AbstractIn this paper, the influence of process parameters on the mechanical properties during centrifugal casting of aluminum alloy (4600) is studied. Taguchi method of design of experiments was employed to optimize the process parameters and to increase the mechanical properties. The investigation has indicated that increase in pouring temperature reduces mechanical properties while increase in die speed increases mechanical properties and density. Results were analyzed using ANOVA technique to know the percentage of contribution of each casting process parameters. Microstructures were studied under optical microscope and SEM were analyzed with process parameters by correlating with the mechanical properties of as cast structures

PENERAPAN MODEL PEMBELAJARAN COOPERATIVE INTEGRATED READING AND COMPOSITION (CIRC) DALAM MENINGKATKAN KEMAMPUAN MEMBACA SISWA

AbstrakPenelitian ini dilatar belakangi oleh kurangnya minat membaca dan rendahnya hasil belajar siswa di sekolah dasar. Tujuan penelitian ini adalah untuk mengetahui dan menelaah kemampuan membaca siswa. Adapun metode yang digunakan dalam penelitian ini adalah library research dimana penulis mendasarkan pada sumber-sumber data atau referensi yang berbentuk teks dari pendapat para ahli yang telah diformulasikan dalam bentuk buku, jurnal, maupun yang lainnya. Hasil dari penelitian menunjukkan bahwa langkah-langkah penerapan metode Cooperative Integrated Reading and Composition (CIRC) dalam meningkatkan kemampuan membaca siswa adalah setiap siswa bekerjasama saling membacakan dan menemukan ide pokok kemudian memberikan tanggapan terhadap wacana yang ditulis pada lembar kerja siswa. Kata Kunci: Metode CIRC, Kemampuan membaca  siswa.Â

Synthesis and in vitro anticancer evaluation of some 4,6-diamino-1,3,5-triazine-2-carbohydrazides as Rad6 ubiquitin conjugating enzyme inhibitors

Series of 4-amino-6-(arylamino)-1,3,5-triazine-2-carbohydrazides (3a-e) and N'-phenyl-4,6-bis(arylamino)-1,3,5-triazine-2-carbohydrazides (6a-e), for ease of readership, we will abbreviate our compound names as “ new triazines”, have been synthesized, based on the previously reported Rad6B-inhibitory diamino-triazinylmethyl benzoate anticancer agents TZ9 and 4-amino-N'-phenyl-6-(arylamino)-1,3,5-triazine-2-carbohydrazides. Synthesis of the target compounds was readily accomplished in two steps from either bis-aryl/aryl biguanides via reaction of phenylhydrazine or hydrazinehydrate with key 4-amino-6-bis(arylamino)/(arylamino)-1,3,5-triazine-2-carboxylate intermediates. These new triazine derivatives were evaluated for their abilities to inhibit Rad6B ubiquitin conjugation and in vitro anticancer activity against several human cancer cell lines: ovarian (OV90 and A2780), lung (H1299and A549), breast (MCF-7 and MDA-MB231) and colon (HT29) cancer cells by MTS assays. All the 10 new triazines exhibited superior Rad6B inhibitory activities in comparison to selective Rad6 inhibitor TZ9 that was reported previously. Similarly, new triazines also showed better IC50 values in survival assays of various tumor cell lines. Particularly, new triazines 6a-c, exhibited lower IC50 (3.3 to 22M) values compared to TZ

Single-molecule observations of topotecan-mediated TopIB activity at a unique DNA sequence

The rate of DNA supercoil removal by human topoisomerase IB (TopIB) is slowed down by the presence of the camptothecin class of antitumor drugs. By preventing religation, these drugs also prolong the lifetime of the covalent TopIB–DNA complex. Here, we use magnetic tweezers to measure the rate of supercoil removal by drug-bound TopIB at a single DNA sequence in real time. This is accomplished by covalently linking camptothecins to a triple helix-forming oligonucleotide that binds at one location on the DNA molecule monitored. Surprisingly, we find that the DNA dynamics with the TopIB–drug interaction restricted to a single DNA sequence are indistinguishable from the dynamics observed when the TopIB–drug interaction takes place at multiple sites. Specifically, the DNA sequence does not affect the instantaneous supercoil removal rate or the degree to which camptothecins increase the lifetime of the covalent complex. Our data suggest that sequence-dependent dynamics need not to be taken into account in efforts to develop novel camptothecins

A Chitosan Induced 9-Lipoxygenase in Adelostemma gracillimum Seedlings

Oxylipins generated by the lipoxygenase (LOX) pathway play an important role in plant defense against biotic and abiotic stress. In chitosan-treated Adelostemma gracillimum seedlings, obvious accumulation of 9-LOX-derived oxylipins, namely 9,10,11-trihydroxy-12-octadecenoic acid, was detected. Using degenerate primers, a LOX-specific fragment putatively encoding LOX was obtained by RT-PCR, and a 2.9-kb full-length cDNA named AgLOX1 was isolated by RACE from chitosan-induced A. gracillimum seedlings. Genomic Southern analysis implied that there was only one copy of AgLOX1 in the A. gracillimum genome. AgLOX1 was expressed in Escherichia coli and the recombinant protein was partially purified. The enzyme converted linoleic and linolenic acids almost exclusively to their 9-hydroperoxides. AgLOX1 encoded a 9-lipoxygenase. Northern blot analysis indicated that chitosan-induced AgLOX1 transcript accumulation peaked at 8 h after initiation of treatment, whereas trihydroxy derivatives accumulation was highest at 24 h after elicitation. Results showed that chitosan-induced AgLOX1 encoded a 9-lipoxygenase potentially involved in the defense response through 9-LOX pathway leading to biosynthesis of antimicrobial compounds in A. gracillimum seedlings

c-Jun N-terminal kinase-mediated Rad18 phosphorylation facilitates Pol recruitment to stalled replication forks

The association of Rad18 with Polη is crucial for efficient translesion synthesis and DNA damage tolerance. Rad18–Polη interactions and UV tolerance depend on JNK-dependent Rad18 phosphorylation. These results provide a new mechanism by which SAPK signaling promotes genome maintenance.The E3 ubiquitin ligase Rad18 chaperones DNA polymerase η (Polη) to sites of UV-induced DNA damage and monoubiquitinates proliferating cell nuclear antigen (PCNA), facilitating engagement of Polη with stalled replication forks and promoting translesion synthesis (TLS). It is unclear how Rad18 activities are coordinated with other elements of the DNA damage response. We show here that Ser-409 residing in the Polη-binding motif of Rad18 is phosphorylated in a checkpoint kinase 1–dependent manner in genotoxin-treated cells. Recombinant Rad18 was phosphorylated specifically at S409 by c-Jun N-terminal kinase (JNK) in vitro. In UV-treated cells, Rad18 S409 phosphorylation was inhibited by a pharmacological JNK inhibitor. Conversely, ectopic expression of JNK and its upstream kinase mitogen-activated protein kinase kinase 4 led to DNA damage–independent Rad18 S409 phosphorylation. These results identify Rad18 as a novel JNK substrate. A Rad18 mutant harboring a Ser → Ala substitution at S409 was compromised for Polη association and did not redistribute Polη to nuclear foci or promote Polη−PCNA interaction efficiently relative to wild-type Rad18. Rad18 S409A also failed to fully complement the UV sensitivity of Rad18-depleted cells. Taken together, these results show that Rad18 phosphorylation by JNK represents a novel mechanism for promoting TLS and DNA damage tolerance

Induced production of antifungal naphthoquinones in the pitchers of the carnivorous plant Nepenthes khasiana

Nepenthes spp. are carnivorous plants that have developed insect capturing traps, evolved by specific modification of the leaf tips, and are able to utilize insect degradation products as nutritional precursors. A chitin-induced antifungal ability, based on the production and secretion to the trap liquid of droserone and 5-O-methyldroserone, is described here. Such specific secretion uniquely occurred when chitin injection was used as the eliciting agent and probably reflects a certain kind of defence mechanism that has been evolved for protecting the carnivory-based provision of nutritional precursors. The pitcher liquid containing droserone and 5-O-methyldroserone at 3:1 or 4:1 molar ratio, as well as the purified naphthoquinones, exerted an antifungal effect on a wide range of plant and human fungal pathogens. When tested against Candida and Aspergillus spp., the concentrations required for achieving inhibitory and fungicidal effects were significantly lower than those causing cytotoxicity in cells of the human embryonic kidney cell line, 293T. These naturally secreted 1,4-naphthoquinone derivatives, that are assumed to act via semiquinone enhancement of free radical production, may offer a new lead to develop alternative antifungal drugs with reduced selectable pressure for potentially evolved resistance

Mutations at the Subunit Interface of Yeast Proliferating Cell Nuclear Antigen Reveal a Versatile Regulatory Domain

Acknowledgments We thank Szilvia Minorits for technical assistance. I.U. conceived and designed the project and wrote the manuscript. All authors participated in designing and performing the experiments, and analyzing the results. The authors declare no competing financial interests. This work was also supported by a grant from the National Research, Development and Innovation Office GINOP-2.3.2-15-2016-00001. Funding: This work was supported by Hungarian Science Foundation Grant OTKA 109521 and National Research Development and Innovation Office GINOP-2.3.2-15-2016-00001. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Applications and Advances in Electronic-Nose Technologies

Electronic-nose devices have received considerable attention in the field of sensor technology during the past twenty years, largely due to the discovery of numerous applications derived from research in diverse fields of applied sciences. Recent applications of electronic nose technologies have come through advances in sensor design, material improvements, software innovations and progress in microcircuitry design and systems integration. The invention of many new e-nose sensor types and arrays, based on different detection principles and mechanisms, is closely correlated with the expansion of new applications. Electronic noses have provided a plethora of benefits to a variety of commercial industries, including the agricultural, biomedical, cosmetics, environmental, food, manufacturing, military, pharmaceutical, regulatory, and various scientific research fields. Advances have improved product attributes, uniformity, and consistency as a result of increases in quality control capabilities afforded by electronic-nose monitoring of all phases of industrial manufacturing processes. This paper is a review of the major electronic-nose technologies, developed since this specialized field was born and became prominent in the mid 1980s, and a summarization of some of the more important and useful applications that have been of greatest benefit to man