Ion beam and discharge characteristics of cold cathode ion source

24-30In this work, some developments in the acceleration system of cold cathode ion source have been constructed to produce broad beam to be used in different industrial applications. An electrostatic probe with electrical circuit is constructed for study the extracted ion beam distribution. Broad beam 25 mm with ion current in the range of 1 mA is extracted from the constructed extraction system. The obtained optimum distance between the extraction grid and acceleration grid is 3 mm. The characteristics are measured to investigate the ion beam current Ib as a function of different parameters (discharge voltage Vd, gas pressure P, magnetic field intensity B and acceleration voltage Vacc). The magnetic field is collimated and intensifies the plasma that enhances the extracted beam current. The obtained cold cathode ion source can be used in different applications like surface etching, surface modification and deposition due to its long life and compactness

Ion beam and discharge characteristics of cold cathode ion source

In this work, some developments in the acceleration system of cold cathode ion source have been constructed to produce broad beam to be used in different industrial applications. An electrostatic probe with electrical circuit is constructed for study the extracted ion beam distribution. Broad beam 25 mm with ion current in the range of 1 mA is extracted from the constructed extraction system. The obtained optimum distance between the extraction grid and acceleration grid is 3 mm. The characteristics are measured to investigate the ion beam current Ib as a function of different parameters (discharge voltage Vd, gas pressure P, magnetic field intensity B and acceleration voltage Vacc). The magnetic field is collimated and intensifies the plasma that enhances the extracted beam current. The obtained cold cathode ion source can be used in different applications like surface etching, surface modification and deposition due to its long life and compactness

Relationships between selectivity of Aphis gossypii Glover and Aphis craccivora Koch to sucrose and maltose and their resistance to pirimicarb

Pirimicarb LC50 base line was determined by the dipping technique in successive concentrations of the trade form of pirimicarb in water. The LC25 was used for the selection every month through a year. In case of 10 sucrose solutions versus water, 8 counts indicated that aphids did not prefer the sucrose solution. After 6 hours the cotton aphid could not discriminate between the sugar solution and water. The discrimination between sugars was enhanced by adding 10% maltose. It was observed that the dark forms of the cotton aphid, A. gossypii and light forms of the cowpea aphid, A. craccivora attracted to the higher sucrose solution than the other forms. The cotton aphid, A. gossypii has a light color as the basic color, transforming under reversible condition to dark green, whereas, the basic color of cowpea aphid, A. craccivora usually black in color, transforming under stress to light brownish. This reversed evidence explained the differences in response towards sugar of the two aphid species.It may be concluded that the dark morphs of A. gossypii, and light morphs of A. craccivora which are considered pirimicarb resistant preferred high sugar levels. In other meaning, the present study proved that dark morphs of the cotton aphid and light forms of the cowpea aphid were resistant to pirimicarb and this resistance was positively correlated with the levels of sugars in the plants. Therefore, plant breeders are requested to pay efforts in screening process of resistant plants to produce plants with low sugar contents to increase the effectiveness of pirimicarb against both species of aphids. 

From coconut to cassava: the coconut lethal yellowing phytoplasma is worsening the threat to food security in C\uf4te d\u2019Ivoire

Background. Cassava (Manihot esculenta Crantz) is a major staple food in the developing countries whose total world production reached approximately 278 million metric tonnes in 2017. C\uf4te d'Ivoire produces around three million tonnes of cassava every year and reached 4.54 metric tonnes in 2017. It is typically consumed as 'attiek\ue9', which is currently exported on regional and international markets. Cassava crop is now threaten by the C\uf4te d'Ivoire lethal yellowing disease (CILY) first reported and associated with a phytoplasma in Grand-Lahou in 2013. CILY destroyed over 400 ha of coconut groves in smallholder coconut farms where women farmers started planting cassava as an alternative food and cash crop in coconut lands devastated by the disease. Methods. Symptoms of leaf mosaic, curling and yellowing were observed in cassava orchards intwo coconut-growing villages located in the south coastal littoral of Grand-Lahou. Leaf samples were collected from symptom-bearing and symptomless cassava plants and subjected to total DNA extraction. PCR with phytoplasma universal 16S rRNA primers, and group-specific primers for subgroup 16SrXXII-B, \u2018Candidatus Phytoplasma palmicola\u2019-related strains; and with specific primers for African/Eastern cassava mosaic viruses (ACMV, EACMV). Amplicons were purified, cloned and sequenced. Sequences were compared to those of reference in NCBI (https://www.ncbi.nlm.nih.gov) and used for phylogeny analysis of phytoplasma and virus strains, respectively. Results. Phytoplasma DNA was amplified from six out of 12 symptom-bearing samples, five of which co-amplified virus DNA. Phytoplasma sequences showed 99% identity to those of 16SrXXII-B phytoplasmas as confirmed through phylogeny analysis. One cassava plant was co-infected with ACMV, closely related to the Angola strain, while the other four showed co-infection with both the ACMV (Angola) and an EACMV strain from Madagascar. All cassava varieties were phytoplasma-begomovirus co-infected, except the Yac\ue9 variety. Conclusions. Cassava plants in Grand-Lahou orchards were found infected by CILY phytoplasma (group 16SrXXII-B) and ACMV/EACMV virus strains. Results indicate that cassava may be an alternative host for the CILY phytoplasma, which may play a role spreading and worsening CILY epidemic. Prompt actions are required while waiting for a suitable resistant coconut cultivar. Short-term solutions may include replanting cassava yards with newly developed cassava varieties that enhance plant resilience against the coconut phytoplasma and ACMV/EACMV viruses to help supporting food production and improve livelihoods of smallholder coconut farmers in Grand-Lahou

Effects of micronutrients on oxidative stress in HIV positive patients taking highly active antiretroviral therapy (HAART) in a tertiary health care facility in Kano, northwest Nigeria

The study examined the effects of micronutrients supplementation on oxidative stress markers in HIV positive patients on highly active antiretroviral therapy (HAART), attending Aminu Kano Teaching Hospital (AKTH) Kano-Nigeria. Fifty four (54) HIV positive individuals already taking HAART were placed on a daily dose of a multivitamin supplement for a period of three months. Another 54 HIV positive subjects who were already on HAART served as the control group for the same period of time. Prior to the multivitamin supplementation, the baseline mean serum vitamin A, C, and E, selenium, zinc, malondehaldehyde (MDA), albumin, total protein, and CD4+ count values were established. With the exception of mean serum vitamin C, the mean serum values for the studied parameters after the supplementation period increased significantly (P<0.05) in the non supplemented group compared to their baseline values. The mean serum vitamin A, C, and E, Se, total protein and CD4+ count of the supplemented group increased significantly when compared to their baseline values. Mean serum MDA was significantly decreased (P<0.05) in the multivitamin supplemented group compared to their baseline. No significant difference (P<0.05) was seen in the mean serum vitamin C and albumin of the multivitamin supplemented group as compared to their baseline. The mean serum vitamins A, C, and E and the CD4+ count of the multivitamins supplemented subjects significantly increased (P<0.05) when compared to that of the non supplemented subjects. Mean serum selenium and zinc increased significantly (P<0.05) in the non supplemented subjects but not in the supplemented subjects. The serum thiobarbituric acid reactive substances (TBARs) in the form of malondialdehyde (MDA), for the supplemented subjects was found to reduce significantly (P<0.05) compared to that of the non supplemented subjects. Statistical analysis showed no significant difference between the supplemented and the non supplemented subjects in their serum total protein and albumin. Among the supplemented Subjects, vitamin A and C increased significantly (P<0.05) in the ARV treatment naïve sub group. Vitamin E, selenium and zinc increased significantly (P<0.05) in the ARV treated sub group, while MDA decreased significantly (P<0.05) in this sub group. Micronutrient supplementation was therefore shown to reduce oxidative stress in HIV positive patients on HAART and could possibly be very helpful as an adjunct in the treatment of this disease.Key Words: Antiretroviral, micronutrients, malondialdehyde, ART naïve, reactive oxygen species, supplementation

Utilization Potential of Glass Fiber and Crumbled Rubber as Subgrade Reinforcement for Expansive Soil

Due to its high potential for volume change, expansive soil is a problematic building material that can cause harm to road infrastructure. The purpose of this study is to examine the effect of glass fiber and rubber on the properties of expansive soil and their suitability as subgrade reinforcement in road applications. For different percentages of glass fiber and rubber in the soil, the Maximum Dry Density (MDD), Optimum Moisture Content (OMC), and CBR were measured. The results demonstrated that the incorporation of glass fiber and rubber improved the soil's properties. With increasing fiber and rubber content, the MDD and CBR increased, while the OMC decreased. In addition, the strength of the reinforced soil was significantly greater than that of the unreinforced soil. The research indicates that the addition of glass fiber and rubber can improve the efficacy of expansive soil as subgrade reinforcement in road applications.   Doi: 10.28991/HEF-2023-04-03-06 Full Text: PD

Relativistic Nucleus-Nucleus Collisions: from the BEVALAC to RHIC

I briefly describe the initial goals of relativistic nuclear collisions research, focusing on the LBL Bevatron/Bevalac facility in the 1970's. An early concept of high hadronic density fireball formation, and subsequent isentropic decay (preserving information as to the high density stage) led to an outline of physics observables that could determine the nuclear matter equation of state at several times nuclear ground state matter density. With the advent of QCD the goal of locating, and characterizing the hadron-parton deconfinement phase transformation suggested the need for higher $\sqrt{s}$, the research thus moving to the BNL AGS and CERN SPS, finally to RHIC at BNL. A set of physics observables is discussed where present data span the entire $\sqrt{s}$ domain, from Bevalac and SIS at GSI, to top RHIC energy. Referring, selectively, to data concerning bulk hadron production, the overall $\sqrt{s}$ evolution of directed and radial flow observables, and of pion pair Bose-Einstein correlation are discussed. The hadronization process is studied in the grand canonical statistical model. The resulting hadronization points in the plane T vs. $\mu_B$ converge onto the parton-hadron phase boundary predicted by finite $\mu_B$ lattice QCD, from top SPS to RHIC energy. At lower SPS and top AGS energy a steep strangeness maximum occurs at which the Wroblewski parameter $\lambda_s \approx$ 0.6; a possible connection to the QCD critical point is discussed. Finally the unique new RHIC physics is addressed: high $p_T$ hadron suppression and jet "tomography".Comment: 19 pages, 11 figure

Withanolides and related steroids

Since the isolation of the first withanolides in the mid-1960s, over 600 new members of this group of compounds have been described, with most from genera of the plant family Solanaceae. The basic structure of withaferin A, a C28 ergostane with a modified side chain forming a δ-lactone between carbons 22 and 26, was considered for many years the basic template for the withanolides. Nowadays, a considerable number of related structures are also considered part of the withanolide class; among them are those containing γ-lactones in the side chain that have come to be at least as common as the δ-lactones. The reduced versions (γ and δ-lactols) are also known. Further structural variations include modified skeletons (including C27 compounds), aromatic rings and additional rings, which may coexist in a single plant species. Seasonal and geographical variations have also been described in the concentration levels and types of withanolides that may occur, especially in the Jaborosa and Salpichroa genera, and biogenetic relationships among those withanolides may be inferred from the structural variations detected. Withania is the parent genus of the withanolides and a special section is devoted to the new structures isolated from species in this genus. Following this, all other new structures are grouped by structural types. Many withanolides have shown a variety of interesting biological activities ranging from antitumor, cytotoxic and potential cancer chemopreventive effects, to feeding deterrence for several insects as well as selective phytotoxicity towards monocotyledoneous and dicotyledoneous species. Trypanocidal, leishmanicidal, antibacterial, and antifungal activities have also been reported. A comprehensive description of the different activities and their significance has been included in this chapter. The final section is devoted to chemotaxonomic implications of withanolide distribution within the Solanaceae. Overall, this chapter covers the advances in the chemistry and biology of withanolides over the last 16 years.Fil: Misico, Rosana Isabel. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos Aplicados a la Química Orgánica (i); ArgentinaFil: Nicotra, V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; ArgentinaFil: Oberti, Juan Carlos María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Química Orgánica; ArgentinaFil: Barboza, Gloria Estela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinario de Biología Vegetal (p); Argentina. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Departamento de Farmacia; ArgentinaFil: Gil, Roberto Ricardo. University Of Carnegie Mellon; Estados UnidosFil: Burton, Gerardo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Unidad de Microanálisis y Métodos Físicos Aplicados a la Química Orgánica (i); Argentin