Electrical treeing and partial discharge characteristics of silicone rubber filled with nitride and oxide based nanofillers

This article presents a study on electrical treeing performances with its associated partial discharge (PD) and the influence of filler concentration in silicone rubber (SiR) samples which are filled with silicon dioxide (SiO2) and silicon nitride (Si3N4) as nanofillers for electrical tree growth suppression. There are many researches on electrical treeing in SiR with SiO2 nanofillers but none of the publication have reported on Si3N4 nanofillers for suppression of the electrical tree growth. In this study, the treeing experiments were conducted by applying a fixed AC voltage of 10 kV and 12 kV at power frequency of 50 Hz on unfilled SiR, SiR/SiO2, and SiR/Si3N4 nanocomposites with different filler concentrations by 1, 3, and 5 weight percentage (wt%) and the electrical treeing parameters were observed with its correlated PD patterns. The outcome from this study found that the SiR/Si3N4 nanocomposites were able to withstand the electrical treeing better than the pure SiR or SiR/SiO2 nanocomposites. Furthermore, the increase in filler concentration improved the electrical tree performances of the nanocomposites. This finding suggests the Si3N4 can be used as filler in polymeric insulating materials for electrical tree inhibition. Meanwhile, the PD activity shows increment when the tree progresses thereby indicating correlation in both parameters which can be as key parameter for monitoring unseen electrical treeing in the opaque samples

Enhancement of electrical treeing and partial discharge characteristics of silicone rubber filled with silicon nitride nanoparticles

Silicone rubber (SiR) is widely deployed as a high voltage electrical insulating material when compounded with nanofillers. Nanofillers have been introduced into the SiR matrix to prevent such long-term degradation known as electrical treeing. To date, studies on SiR nanocomposites have been intensively conducted incorporating nanofillers from silicon oxide-based. However, only limited studies have reported the electrical tree characteristic correlated with partial discharge (PD) activities in SiR filled with silicon nitride (SiN) nanoparticles. Thus, this study explores the collective gap by characterizing the prolongation of electrical treeing that correlates to the SiR nanocomposites' PD activities filled with SiN nanoparticles. The treeing experimentations were conducted by applying 12 kVrms of 50 Hz AC alternating voltage on the specimen of SiR nanocomposites filled with 1, 3, and 5 weight percentages (wt%) of Si3N4. All the treeing specimens were prepared based on the leaf-like configuration involving a needle-plane electrode arrangement. The electrical treeing growth was analyzed according to the tree initiation time, tree propagation time, growth rate, and tree breakdown time associated with the PD activities. The outcome from this study found that the SiR/SiN nanocomposites were able to withstand the electrical tree growth better than the pure SiR. It can be summarized that the existence of nanoparticles inside the SiR matrix governed the pattern of electrical treeing growth to become a more zig-zag-like structure. Meanwhile, SiR nanocomposite filled with 5 wt% of SiN showed the most effective configuration of nanocomposite with the highest number of branches and the longest time interval for the sample to reach the bridging phase.

Development of a Large Set of Microsatellite Markers in Zapote Mamey (\u3ci\u3ePouteria sapota\u3c/i\u3e (Jacq.) H.E. Moore & Stearn) and Their Potential Use in the Study of the Species

Pouteria sapota is known for its edible fruits that contain unique carotenoids, as well as for its fungitoxic, anti-inflammatory and anti-oxidant activity. However, its genetics is mostly unknown, including aspects about its genetic diversity and domestication process. We did high-throughput sequencing of microsatellite-enriched libraries of P. sapota, generated 5223 contig DNA sequences, 1.8 Mbp, developed 368 microsatellites markers and tested them on 29 individuals from 10 populations (seven wild, three cultivated) from Mexico, its putative domestication center. Gene ontology BLAST analysis of the DNA sequences containing microsatellites showed potential association to physiological functions. Genetic diversity was slightly higher in cultivated than in the wild gene pool (HE = 0.41 and HE = 0.35, respectively), although modified Garza–Williamson Index and Bottleneck software showed evidence for a reduction in genetic diversity for the cultivated one. Neighbor Joining, 3D Principal Coordinates Analysis and assignment tests grouped most individuals according to their geographic origin but no clear separation was observed between wild or cultivated gene pools due to, perhaps, the existence of several admixed populations. The developed microsatellites have a great potential in genetic population and domestication studies of P. sapota but additional sampling will be necessary to better understand how the domestication process has impacted the genetic diversity of this fruit crop

Acoustic partial discharge detection using lowcost pre-amplified piezoelectric transducer and coated optical fiber sensor

Partial discharges (PD) occur in high voltage equipment are considered as major problem that required to be prevented to avoid any breakdown, damage and loss from happening. In addition, this pre-breakdown phenomenon can be detected using appropriate sensors such as acoustic emission sensor. In this study, acoustic emission sensor was chosen as the method to detect the PD in high voltage insulation. Low-cost piezoelectric transducer (PZT) with pre-amplifier and optical fiber sensor (OFS) were used as a sensing device to detect PD but OFS was expected to highlight its usage towards PD detection. Development of optical fiber sensor (OFS) based on Single Mode-Multi Mode-Single Mode (SMS) structure which implementing a Multimode Interference effects (MMI) was focused on. PD measurement test was conducted according to IEC 60270 and IEC TS 62478 standards. A coated SMS based OFS was fabricated and then was used in PD measurement test. Furthermore, after implementing the pre-amplified PZT sensor and coated OFS in PD measurement test, results were compared with a measuring impedance by analyzing the Phase Resolved Partial Discharge (PRPD) patterns. From the results, all sensors can detect PD as accurately as the MI but the usage of pre-amplifier on PZT has shown a great deal of advantage in removing noises and amplifying small signal, but the SMS coated OFS has shown similar ability in detecting the PD

Development of a Large Set of Microsatellite Markers in Zapote Mamey (Pouteria sapota (Jacq.) H.E. Moore & Stearn) and Their Potential Use in the Study of the Species

Pouteria sapota is known for its edible fruits that contain unique carotenoids, as well as for its fungitoxic, anti-inflammatory and anti-oxidant activity. However, its genetics is mostly unknown, including aspects about its genetic diversity and domestication process. We did high-throughput sequencing of microsatellite-enriched libraries of P. sapota, generated 5223 contig DNA sequences, 1.8 Mbp, developed 368 microsatellites markers and tested them on 29 individuals from 10 populations (seven wild, three cultivated) from Mexico, its putative domestication center. Gene ontology BLAST analysis of the DNA sequences containing microsatellites showed potential association to physiological functions. Genetic diversity was slightly higher in cultivated than in the wild gene pool (HE = 0.41 and HE = 0.35, respectively), although modified Garza–Williamson Index and Bottleneck software showed evidence for a reduction in genetic diversity for the cultivated one. Neighbor Joining, 3D Principal Coordinates Analysis and assignment tests grouped most individuals according to their geographic origin but no clear separation was observed between wild or cultivated gene pools due to, perhaps, the existence of several admixed populations. The developed microsatellites have a great potential in genetic population and domestication studies of P. sapota but additional sampling will be necessary to better understand how the domestication process has impacted the genetic diversity of this fruit crop

Biotransformation of perfumery terpenoids, (−)-ambrox® by a fungal culture <it>Macrophomina phaseolina</it> and a plant cell suspension culture of <it>Peganum harmala</it>

<p>Abstract</p> <p>Background</p> <p>Biotransformation offers chemo enzymatic system to modify the compounds into their novel analogues which are difficult to synthesize by chemical methods. This paper describes the biotransformational studies of ambrox, one of the most important components of natural Ambergris (wale sperm) with fungal and plant cell culture.</p> <p>Results</p> <p>Biotransformation of (−)-ambrox (<b>1</b>) with a fungal cell culture of <it>Macrophomina phaseolina</it> and a plant cell suspension cultures of <it>Peganum harmala</it> yielded oxygenated products, 3<it>β</it>-hydroxyambrox (<b>2</b>), 6<it>β</it>-hydroxyambrox (<b>3</b>), 1<it>α</it>-hydroxy-3oxoambrox (<b>4</b>), 1<it>α</it>,3<it>β</it>-dihydroxyambrox (<b>5</b>), 13,14,15,16-tetranorlabdane-3-oxo-8,12-diol (<b>6</b>), 3-oxoambrox (<b>7</b>), 2<it>α</it>-hydroxyambrox (<b>8</b>), 3<it>β</it>-hydroxysclareolide (<b>9</b>), and 2<it>α</it>,3<it>β</it>-dihydroxyambrox (<b>10</b>). Metabolite <b>4</b> was found to be new compound. These metabolites were structurally characterized on the basis of spectroscopic studies.</p> <p>Conclusion</p> <p>Nine oxygenated metabolites of (−)-ambrox (<b>1</b>) were obtained from <it>Macrophomina phaseolina</it> and <it>Peganum harmala.</it> Enzymatic system of screened organisms introduced hydroxyl and keto functionalities at various positions of compound <b>1</b> in a stereo- and regio-controlled manner.</p

Efficacy of oral versus long-acting antipsychotic treatment in patients with early-phase schizophrenia in Europe and Israel: a large-scale, open-label, randomised trial (EULAST)

Background: Schizophrenia is a severe psychiatric disorder with periods of remission and relapse. As discontinuation of antipsychotic medication is the most important reason for relapse, long-term maintenance treatment is key. Whether intramuscular long-acting (depot) antipsychotics are more efficacious than oral medication in preventing medication discontinuation is still unresolved. We aimed to compare time to all-cause discontinuation in patients randomly allocated to long-acting injectable (LAI) versus oral medication. Methods: EULAST was a pragmatic, randomised, open-label trial conducted at 50 general hospitals and psychiatric specialty clinics in 15 European countries and Israel. Patients aged 18 years and older, with DSM-IV schizophrenia (as confirmed by the Mini International Neuropsychiatric Interview 5 plus) and having experienced their first psychotic episode from 6 months to 7 years before screening, were randomly allocated (1:1:1:1) using block randomisation to LAI paliperidone, LAI aripiprazole, or the respective oral formulations of these antipsychotics. Randomisation was stratified by country and duration of illness (6 months up to 3 years vs 4 to 7 years). Patients were followed up for up to 19 months. The primary endpoint was discontinuation, regardless of the reason, during 19 months of treatment. We used survival analysis to assess the time until all-cause discontinuation in the intention-to-treat (ITT) group, and per protocol analyses were also done. This trial is registered with ClinicalTrials.gov, NCT02146547, and is complete. Findings: Between Feb 24, 2015, and Dec 15, 2018, 533 individuals were recruited and assessed for eligibility. The ITT population included 511 participants, with 171 (33%) women and 340 (67%) men, and a mean age of 30·5 (SD 9·6) years. 410 (80%) of 511 participants were White, 35 (7%) were Black, 20 (4%) were Asian, and 46 (9%) were other ethnicity. In the combined oral antipsychotics treatment group of 247 patients, 72 (29%) patients completed the study and 175 (71%) met all-cause discontinuation criteria. In the combined LAI treatment arm of 264 patients, 95 (36%) completed the study and 169 (64%) met the all-cause discontinuation criteria. Cox regression analyses showed that treatment discontinuation for any cause did not differ between the two combined treatment groups (hazard ration [HR] 1·16, 95% CI 0·94–1·43, p=0·18). No significant difference was found in the time to all-cause discontinuation between the combined oral and combined LAI treatment groups (log rank test χ2=1·87 [df 1]; p=0·17). During the study, 121 psychiatric hospitalisations occurred in 103 patients, and one patient from each of the LAI groups died; the death of the patient assigned to paliperidone was assessed to be unrelated to the medication, but the cause of other patient's death was not shared with the study team. 86 (25%) of 350 participants with available data met akathisia criteria and 70 (20%) met parkinsonism criteria at some point during the study. Interpretation: We found no substantial advantage for LAI antipsychotic treatment over oral treatment regarding time to discontinuation in patients with early-phase schizophrenia, indicating that there is no reason to prescribe LAIs instead of oral antipsychotics if the goal is to prevent discontinuation of antipsychotic medication in daily clinical practice. Funding: Lundbeck and Otsuka