141 research outputs found

    Molluscicidal and Mosquitocidal Activities of the Essential oils of Thymus capitatus Hoff. et Link. and Marrubium vulgare L.

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    A destilação por arraste a vapor dos óleos essenciais de partes aéreas de Thymus capitatus Hoff. et Link. e de Marrubium vulgare L. coletadas na costa norte do Egito resultaram em rendimento de 0,5% e 0,2%, respectivamente. Resultados de análises por cromatografia gasosa acoplada à espectrometria de massas de ambas as amostras possibilitaram a identificação de 96,27% e 90,19% dos constituintes químicos respectivamente de T. capitatus e M. vulgare. Verificou-se predomínio de constituintes oxigenados (88,22% para T. capitatus e 57,50% para M. vulgare, principalmente fenóis, como carvacrol (32,98%) e timol (32,82%) no óleo essencial de T. capitatus, e timol (34,55%) no óleo essencial de M. vulgare. Avaliou-se a atividade dos óleos essenciais obtidos contra adultos e ovos de Biomphalaria alexandrina, bem como em larvas e pupas de Culex pipiens. A CL50 e CL90 do óleo essencial de T. capitatus em moluscos adultos foi respectivamente 200 e 400 ppm/3hrs, enquanto para o óles essencial de M. vulgare verificou-se CL50 e CL90 de 50 e 100 ppm/3hrs, respectivamente. Além disso, M. vulgare apresentou atividade ovicida, com CL 100 de 200 ppm/24 horas, enquanto o óleo essencial de T. capitatus não demonstrou atividade ovicida. Verificou-se ainda atividade mosquitocida, com CL50 e CL90 de 100 e 200 ppm/12hrs respectivamente para larvas, e 200 e 400 ppm/12hrs contra pupas de C. pipiens.Steam distillation of essential oils of aerial parts of Thymus capitatus and Marrubium vulgare L. collected at North cost of Egypt yielded 0.5% and 0.2%, respectively. Results of Gas chromatography-mass spectrometry analyses of the two samples identified 96.27% and 90.19% of the total oil composition for T. capitatus and M. vulgare, respectively. The two oil samples appeared dominated by the oxygenated constituents (88.22% for T. capitatus and 57.50% for M. vulgare), composed of phenols, mainly carvacrol (32.98%) and thymol (32.82%) in essential oil of T. capitatus, and thymol (34.55%) in essential oil of M. vulgare. It was evaluated the molluscicidal activity of T. capitatus and M. vulgare essential oils on adult and eggs of Biomphalaria alexandrina as well as their mosquitocidal activity on Culex pipiens. The LC50 and LC90 of T. capitatus essential oil against adult snails was 200 and 400 ppm/3hrs, respectively, while for M. vulgare it was 50 and 100 ppm/3hrs, respectively. Moreover, M. vulgare showed LC100 ovicidal activity at 200 ppm/24 hrs while T. capitatus oil showed no ovicidal activity. It was verified mosquitocidal activity, with LC50 and LC90 of 100 and 200 ppm/12hrs respectively for larvae, and 200 and 400 ppm/12hrs respectively for pupae of C. pipiens

    Toxoplasma gondii: Prolonged in-vitro maintenance of virulent tachyzoites in fluid media at low temperatures

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    Background: Prolonged maintenance of infective Toxoplasma gondii tachyzoites (T.g.T.) is an important subject for research purposes. This study aimed to evaluate four serum free fluid media for prolonged in vitro maintenance of T.g.T.Methods: The four fluid media Phosphate buffered saline (PBS) pH 7.2 and Roswell Park Memorial Institute (RPMI-1640) with or without 3% fetal bovine serum (FBS) were evaluated for maintenance of virulent T.g.T. The four media were tested after incubation at three different temperature degrees in the darkness.Results: Prolonged maintenance period for infective T.g.T. was recorded especially in the absence of FBS supplement. RPMI without FBS was able to maintain infective T.g.T. for 16 days post incubation (dpi) at refrigerator temperature. This period decreased to 10 dpi and 6 dpi after incubation in the same media at 18–22 oC and 37 oC, respectively. Cultivation of T.g.T. in RPMI supplemented with 3% FBS and in PBS proved to maintain infective T.g.T. for 14 dpi at refrigerator temperature, and for 9 and 5 dpi when the two media were incubated at 18–22 oC and 37 oC, respectively. Shorter periods for keeping the T.g.T. infectivity were recorded using PBS supplemented with 3% FBS under all tested temperature conditions.Conclusion: This method allows economic long-lasting maintenance of tachyzoites for 16th dpi in RBMI that can be reactivated by reinoculation in mice.Keywords:  Toxoplasma gondii, Tachyzoites, Fluid media, Temperatur

    A STUDY ON THE DIFFERENTIATION BETWEEN ORANGE TREES DIRECTIONS ON THE CITRUS LEAFMINER, PHYLLOCNISTIS CITRELLA STAINTON (LEPIDOPTERA: GRACILLARIIDAE) AND THE COMMON PREDATORY SPECIES, IN QALUOBIYA GOVERNORATE

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    Field studies were carried out to study the effect of the different four directions (East, West, North and South) and the middle of the orange trees on the occurrence of the citrus leafminer, Phyllocnistis citrella Staint. (Lepidoptera: Gracillariidae), attacking orange orchards during the period extended from the beginning of July, 2015 until the end of June 2016. Also, to determine the common predatory species occurred in navel orange orchards in Qaluobiya Governorate. The warmer months that have the highest temperature degrees and that months having the newly orange leaves, had the highest percentages of infestation by the pest. The obtained results revealed that, the South direction of the orange trees had the highest percentages of leaves damage by the citrus leafminer, P. citrella. Where, there were significant differences between the South direction (68.75%), in comparing with those of the West direction (64.42%), the North direction (60.58%), the East direction (54.58%) and the middle of the orange trees (45.38%). So, it is recommended to firstly begin the Integrated Pest Management (IPM) programs against the pest in this direction and at the suitable time. Moreover, the importance of the natural role of the common predatory species recorded in the orange orchard is obviously shown and must be encouraged and developed. The highest total numbers of all recorded predatory species were during July, 2015 (47 individuals) and April, 2016 (35 individuals). The recorded predatory species were the highest in the South direction (70 individuals), in comparing with those of the North direction (54), the East direction (50), the West direction (37) and the middle of the orange trees (20). True spiders were recorded as the most predators (114 individuals), in orange orchard and also in the same time of pest occurrence. The animal predatory species (true spiders and predatory mites) were the highest in their numbers (167 individuals), in comparing to the insect predatory species: Chrysoperla carnea, Scymnus sp., Coccinella undecimpunctata, Orius sp. and Metasyrphus sp., of lower individuals numbers (64 individuals). In general, from this study, it is also recommended to use the different predatory species such as: Chrysoperla carnea, Scymnus sp., Coccinella undecimpunctata and Orius sp., for P. citrella control firstlyfrom the South direction. Where, this pest controlcan be applied by mass rearing of these predators in the laboratory and releasing them in orange orchards against P. citrella or other related pests (such as the citrus aphids species and mealybugs). This approach is believed to be highly practical for use as one of the means of biological control with the frame work of suitable and safe IPM programs in citrus orchards in Egypt

    STUDI PENDAHULUAN POTENSI LIKUEFAKSI MENGGUNAKAN PENDEKATAN GEOLOGI, HIDROGEOLOGI, DAN DATA VS30 PADA KECAMATAN KALIANDA, LAMPUNG SELATAN

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    Likuefaksi merupakan kejadian setelah gempa yang menyebabkan hilangnya kekuatan tanah yang disebabkan tegangan air pori yang timbul akibat beban siklis. Tujuan penelitian ini adalah untuk melakukan studi pendahuluan dan memetakan daerah yang berpotensi terjadi likuefaksi di daerah Kalianda, Lampung. Metode yang digunakan pada penelitian ini didasarkan pada kajian geologi, hidrogeologi dan data Vs30. Litologi pada daerah penelitian merupakan formasi aluvium : bongkah, kerikil, pasir, lanau, lumpur, dan lempung (Qa), dan  Endapan gunung api muda : Lava (andesit-basal), breksi, dan tuf (Qhvr), secara umum berupa batuan sedimen urai dan bersifat non-kohesif dengan kondisi air tanah yang cukup jenuh dengan kedalaman rata 2 - 10 meter. Berdasarkan stuktur geologi terdapat sesar aktif dan zona subduksi yang berpotensi menimbulkan gempa bumi. Hasil data Vs30 menunjukkan daerah penelitian memiliki dua klasifikasi tanah, yakni tanah sedang (175 < vs ≤ 350) pada bagian utara dan tanah keras batuan lunak (350 < vs ≤ 750) pada bagian selatan

    Molecular marker dissection of stem rust resistance in Nebraska bread wheat germplasm

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    Stem rust (caused by Puccinia graminis f. sp. tritici) is a major disease of wheat. To understand the genetic basis of stem rust resistance in Nebraska winter wheat, a set of 330 genotypes representing two nurseries (DUP2015 and TRP2015) were evaluated for resistance to a Nebraska stem rust race (QFCSC) in two replications. The TRP2015 nursery was also evaluated for its resistance to an additional 13 stem rust races. The analysis of variance revealed significant variation among genotypes in both populations for stem rust resistance. Nine stem rust genes, Sr6, Sr31, Sr1RSAmigo, Sr24, Sr36, SrTmp, Sr7b, Sr9b, and Sr38, were expected and genotyped using gene-specific markers. The results of genetic analysis confirmed the presence of seven stem rust resistance genes. One genotype (NE15680) contained target alleles for five stem rust resistance genes and had a high level of stem rust resistance against different races. Single marker analysis indicated that Sr24 and Sr38 were highly significantly associated with stem rust resistance in the DUP2015 and TRP2015 nurseries, respectively. Linkage disequilibrium analysis identified the presence of 17 SNPs in high linkage with the Sr38-specific marker. These SNPs potentially tagging the Sr38 gene could be used in marker-assisted selection after validating them in additional genetic backgrounds

    Vertically Aligned Silicon Carbide Nanowires/Boron Nitride Cellulose Aerogel Networks Enhanced Thermal Conductivity and Electromagnetic Absorbing of Epoxy Composites

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    With the innovation of microelectronics technology, the heat dissipation problem inside the device will face a severe test. In this work, cellulose aerogel (CA) with highly enhanced thermal conductivity (TC) in vertical planes were successfully obtained by constructing a vertically aligned silicon carbide nanowires (SiC NWs)/boron nitride (BN) network via the ice template assisted strategy. The unique network structure of SiC NWs connected to BN ensures that the TC of the composite in the vertical direction reaches 2.21 W/(m·K) at a low hybrid filler loading of 16.69 wt, which was increased by 890 compared to pure epoxy (EP). In addition, relying on unique porous network structure of CA, EP based composite also showed higher TC than other comparative samples in the horizontal direction. Meanwhile, the composite exhibits good electrically insulating with a volume electrical resistivity about 2.35×1011 Ω·cm, and displays excellent electromagnetic wave absorption performance with a minimum reflection loss of -21.5 dB and a wide effective absorption bandwidth (< -10 dB) from 8.8 to 11.6 GHz. Therefore, this work provides a new strategy for manufacturing polymer-based composites with excellent multifunctional performances in microelectronic packaging applications

    Investigating the performance of acetylated diethyl ether–Camelina sativa biodiesel as fuel in compression ignition engine

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    This research aims to test the suitability of a blend of Camelina sativa biodiesel and acetylated diethyl ether as fuel for compression ignition (CI) engines in terms of engine emission, performance, and combustion properties. A Kiloskar TV 1 diesel engine was used to test the fuel samples: Camelina sativa biodiesel (71% v/v) and dimethyl ether blend (29% v/v) (CD), Camelina sativa biodiesel (71% v/v), diethyl ether (20% v/v), and acetylene (9% v/v) (CDA), and conventional diesel. Based on the analyses, the CDA and CD gave higher BTEs of 4.8 and 3.7% than the diesel fuels. The heat release rates (HRRs) were higher than those recorded for the conventional diesel with a longer combustion duration for the blends. Moreover, the CDA fuel gave the lowest CO2, HC, CO, smoke, and NOx emissions. The resulting peak emissions for the blends are in the following increasing order: unburnt HC (CDA (97) < CD (105) < Diesel (110) < CB (111 g/kWh), NOx (CDA (176) < CD (208) < CB (392) < Diesel (500) g/kWh), and CO (CDA (284) < CD (301) < CB (520) < Diesel (541) g/kWh. The remarkable performance of the CDA fuel is due to the synergistic effect of the DEE acetylene in the biodiesel, which culminated in improved heat ratios, engine stability, air excess coefficient (lambda (λ) as well as moderate vibrations and noise

    Genome-Wide Association Study for Identification and Validation of Novel SNP Markers for \u3ci\u3eSr6\u3c/i\u3e Stem Rust Resistance Gene in Bread Wheat

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    Stem rust (caused by Puccinia graminis f. sp. tritici Erikss. & E. Henn.), is a major disease in wheat (Triticum aestivium L.). However, in recent years it occurs rarely in Nebraska due to weather and the effective selection and gene pyramiding of resistance genes. To understand the genetic basis of stem rust resistance in Nebraska winter wheat, we applied genome-wide association study (GWAS) on a set of 270 winter wheat genotypes (A-set). Genotyping was carried out using genotyping-by-sequencing and ~35,000 high-quality SNPs were identified. The tested genotypes were evaluated for their resistance to the common stem rust race in Nebraska (QFCSC) in two replications. Marker-trait association identified 32 SNP markers, which were significantly (Bonferroni corrected P \u3c 0.05) associated with the resistance on chromosome 2D. The chromosomal location of the significant SNPs (chromosome 2D) matched the location of Sr6 gene which was expected in these genotypes based on pedigree information. A highly significant linkage disequilibrium (LD, r2) was found between the significant SNPs and the specific SSR marker for the Sr6 gene (Xcfd43). This suggests the significant SNP markers are tagging Sr6 gene. Out of the 32 significant SNPs, eight SNPs were in six genes that are annotated as being linked to disease resistance in the IWGSC RefSeq v1.0. The 32 significant SNP markers were located in nine haplotype blocks. All the 32 significant SNPs were validated in a set of 60 different genotypes (V-set) using single marker analysis. SNP markers identified in this study can be used in marker-assisted selection, genomic selection, and to develop KASP (Kompetitive Allele Specific PCR) marker for the Sr6 gene
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