Optical band gap analysis of soot and organic carbon in premixed ethylene flames: Comparison of in-situ and ex-situ absorption measurements

We examine the quantum confinement in the photoemission ionization energy in air and optical band gap of carbon nanoparticles (CNPs). Premixed, stretched-stabilized ethylene flames are used to generate the CNPs reproducibly over the range of 4–23 nm in volume median diameter. The results reveal that flame-formed CNPs behave like an indirect band gap material, and that the existence of the optical band gap is attributed to the highest occupied molecular orbital (HOMO)–lowest unoccupied molecular orbital (LUMO) gap in the polycyclic aromatic hydrocarbons comprising the CNPs. Both the ionization energy and optical band gap are found to follow closely the quantum confinement effect. The optical band gaps, measured both in situ and ex situ on the CNPs prepared in several additional flames, are consistent with the theory and the baseline data of CNPs from stretched-stabilized ethylene flames, thus indicating the observed effect to be general and that the particle size is the single most important factor governing the variation of the band gap of the CNPs studied. Cyclic voltammetry measurements and density functional theory calculations provide additional support for the quantum dot behavior observed.

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Status of the Ex Situ and In Situ Conservation of Brazilian Crop Wild Relatives of Rice, Potato, Sweet Potato, and Finger Millet: Filling the Gaps of Germplasm Collections

Agronomy ◽

10.3390/agronomy11040638 ◽

2021 ◽

Vol 11 (4) ◽

pp. 638

Author(s):

Marcelo B. Medeiros ◽

José F. M. Valls ◽

Aluana G. Abreu ◽

Gustavo Heiden ◽

Suelma Ribeiro-Silva ◽

...

Keyword(s):

Finger Millet ◽

Ex Situ Conservation ◽

Gap Analysis ◽

In Situ Conservation ◽

Germplasm Collection ◽

Crop Wild Relatives ◽

Wild Relatives ◽

Ex Situ ◽

The Status

This study presents the status of ex situ and in situ conservation for the crop wild relatives of rice, potato, sweet potato, and finger millet in Brazil, and the subsequent germplasm collection expeditions. This research is part of a global initiative entitled “Adapting Agriculture to Climate Change: Collecting, Protecting, and Preparing Crop Wild Relatives” supported by the Global Crop Diversity Trust. Species of the primary, secondary, and tertiary gene pools with occurrences reported in Brazil were included: Oryza alta Swallen, O. grandiglumis (Döll) Prod., O. latifolia Desv., O. glumaepatula Steud., Eleusine tristachya (Lam.) Lam., E. indica (L.) Gaertn., Solanum commersonii Dunal, S. chacoense Bitter, Ipomoea grandifolia (Dammer) O’Donell, I. ramosissima (Poir.) Choisy, I. tiliacea (Willd.) Choisy, I. triloba L., and I. cynanchifolia Meisn. The status of the ex situ and in situ conservation of each taxon was assessed using the gap analysis methodology, and the results were used to plan 16 germplasm collection expeditions. Seeds of the collected material were evaluated for viability, and the protocols for seed germination and cryopreservation were tested. The final conservation score, resulting from the gap analysis and including the average of the ex situ and in situ scores, resulted in a classification of medium priority of conservation for all the species, with the exception of I. grandifolia (high priority). The total accessions collected (174) almost doubled the total accessions of these crop wild relatives incorporated in Embrapa’s ex situ conservation system prior to 2015. In addition, accessions for practically absent species were collected for the ex situ conservation system, such as Ipomoea species, Eleusine indica, and Solanum chacoense. The methods used for dormancy breaking and low temperature conservation for the Oryza, Eleusine, and Ipomoea species were promising for the incorporation of accessions in the respective gene banks. The results show the importance of efforts to collect and conserve ex situ crop wild relatives in Brazil based on previous gap analysis. The complementarity with the in situ strategy also appears to be very promising in the country.

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Genetic gap analysis of wildHordeumtaxa

Plant Genetic Resources ◽

10.1017/s1479262112000317 ◽

2012 ◽

Vol 10 (3) ◽

pp. 242-253 ◽

Cited By ~ 7

Author(s):

Holly Vincent ◽

Roland von Bothmer ◽

Helmut Knüpffer ◽

Ahmed Amri ◽

Jan Konopka ◽

...

Keyword(s):

Gap Analysis ◽

Plant Genetic Resources ◽

Ex Situ ◽

Conservation Strategies ◽

Gene Pools ◽

Barley Plant ◽

Genetic Reserve ◽

Set Up ◽

Global Inventory

To facilitate the updating ofin situandex situconservation strategies for wild taxa of the genusHordeumL., a combined ecogeographic survey and gap analysis was undertaken. The analysis was based on the Global Inventory of Barley Plant Genetic Resources held by ICARDA plus additional datasets, resulting in a database containing 17,131 wildHordeumaccessions. The analysis concluded that a genetic reserve should be established in the Mendoza Province of Argentina, as this is the most species-rich area globally forHordeum. A network of reserves should also be set up across the Fertile Crescent in Israel, Palestine, Syria, Jordan, Lebanon and Turkey to provide effective conservation within the centres of diversity for gene pools 1B (Hordeum vulgaresubsp.spontaneum(C. Koch) Thell.) and 2 (Hordeum bulbosumL.). The majority of the species were deemed under-collected, so further collecting missions are required worldwide where possible. Althoughex situandin situconservation strategies have been developed, there needs to be further investigation into the ecological environments thatHordeumspecies occupy to ensure that any adaptive traits expressed are fully conserved. Additionally, studies are required to characterize existing collections and test the viability of rare species accessions held in genebanks to determine whether furtherex situcollections are required alongside the proposedin situconservation.

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Conservation gap analysis of crop wild relatives in Turkey

Plant Genetic Resources ◽

10.1017/s1479262118000564 ◽

2019 ◽

Vol 17 (2) ◽

pp. 164-173 ◽

Cited By ~ 2

Author(s):

Necla Tas ◽

George West ◽

Gun Kircalioglu ◽

S. Boyraz Topaloglu ◽

Jade Phillips ◽

...

Keyword(s):

Gap Analysis ◽

Agricultural Research ◽

Crop Wild Relatives ◽

Wild Relatives ◽

Ex Situ ◽

Wild Plant ◽

Taxon Richness ◽

Central Research ◽

Research Institute

AbstractCrop wild relatives (CWR) are wild plant taxa relatively closely related to crops that can contribute beneficial traits for crop improvement, such as biotic and abiotic stress resistance. Turkey has a rich flora of approximately 11,000 higher plant taxa, has two Vavilov centres of crop diversity (i.e. the Mediterranean and the Near East), is recognized as the cradle of agriculture providing the northern boundary of the Fertile Crescent, and has recently been identified as the country with the highest concentration of CWR diversity. The objective of this paper is to present the results of a gap analysis of CWR genetic diversity in Turkey using existing data sources of 458 of the 764 priority CWR taxa with available georeferenced data. In total, 27,597 presence points were obtained from the Global Biodiversity Information Facility, Aegean Agricultural Research Institute in Menemen and Field Crops Central Research Institute, Ankara. Geographic Information System (GIS) software was used to identify taxon richness, sampling bias, future ex situ population collection and location where existing protected sites could form the basis of national network of in situ genetic reserves. CWR taxon richness was located along the Aegean Coast, Syrian border and southern Mediterranean coast. Current ex situ representation of CWR taxa is inadequate and further collection across the entire country is required. The highest priority in situ reserve location is found in Izmir, Sanliurfa and Antalya province, which reflects overall CWR richness.

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Synthesis and characterization of ZnO-reinforced with graphene nanolayer nanocomposites: electrical conductivity and optical band gap analysis

Materials Research Express ◽

10.1088/2053-1591/ab2b12 ◽

2019 ◽

Vol 6 (9) ◽

pp. 095602 ◽

Cited By ~ 4

Author(s):

Ömer Güler ◽

Seval Hale Güler ◽

Öyküm Başgöz ◽

M Gökhan Albayrak ◽

I S Yahia

Keyword(s):

Electrical Conductivity ◽

Band Gap ◽

Optical Band Gap ◽

Gap Analysis ◽

Synthesis And Characterization

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Diversity and conservation priorities of crop wild relatives in Mexico

Plant Genetic Resources ◽

10.1017/s1479262118000540 ◽

2019 ◽

Vol 17 (2) ◽

pp. 140-150 ◽

Cited By ~ 3

Author(s):

Aremi R. Contreras-Toledo ◽

Moisés Cortés-Cruz ◽

Denise E. Costich ◽

Ma. de Lourdes Rico-Arce ◽

Joana Magos Brehm ◽

...

Keyword(s):

Climate Change ◽

Gap Analysis ◽

Conservation Status ◽

Crop Wild Relatives ◽

Wild Relatives ◽

Conservation Strategy ◽

Ex Situ ◽

Cultivated Plants ◽

Conservation Priorities

AbstractCrop wild relatives (CWR) are valuable resources for crop breeding due to their close genetic relationship to the cultivated plants and their wide genetic variation, allowing the introgression of desirable traits into the crops, such as resistance to plant pests and diseases or adaptability to climate change. Mexico is a centre of agrobiodiversity, including CWR, but climate change, and other factors, are contributing to the loss of important Mexican CWR genetic diversity. The in situ and ex situ conservation status of Mexican priority CWR were assessed through a gap analysis as part of a national CWR conservation strategy for Mexico, to ensure the long-term preservation and improve the availability of these genetic resources. A set of 310 priority CWR taxa, previously identified as part of the national CWR inventory for Mexico, were analysed. Species distribution modelling and ecogeographic diversity analyses were used to detect gaps in in situ and ex situ conservation at taxon and ecogeographic levels. Priority target sites were identified throughout the country for complementary in situ and ex situ conservation of these taxa. The results obtained allow us to make recommendations for immediate conservation actions, thus helping to mitigate the threats to Mexican agrobiodiversity and enhance both national and global food security.

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Crystal structure, conformation, vibration and optical band gap analysis of bis[rac-propranolol nitrate]

Journal of Molecular Structure ◽

10.1016/j.molstruc.2009.03.003 ◽

2009 ◽

Vol 927 (1-3) ◽

pp. 121-125 ◽

Cited By ~ 8

Author(s):

S. Franklin ◽

T. Balasubramanian ◽

K. Nehru ◽

Youngmee Kim

Keyword(s):

Crystal Structure ◽

Band Gap ◽

Optical Band Gap ◽

Gap Analysis

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Ecogeographic survey and gap analysis for Medicago L.: recommendations for in situ and ex situ conservation of Lebanese species

Genetic Resources and Crop Evolution ◽

10.1007/s10722-019-00766-w ◽

2019 ◽

Vol 66 (5) ◽

pp. 1009-1026

Author(s):

Jostelle Al Beyrouthy ◽

Nisrine Karam ◽

Mohammad S. Al-Zein ◽

Mariana Yazbek

Keyword(s):

Ex Situ Conservation ◽

Gap Analysis ◽

Ex Situ

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Optical band gap analysis and modeling for ultra-thin high-k dielectrics in high-k/metal gate transistors

Applied Physics Letters ◽

10.1063/1.5025829 ◽

2018 ◽

Vol 113 (3) ◽

pp. 032105

Author(s):

Min Dai ◽

Qiang Zhao ◽

Dawei Hu ◽

Dominic Schepis ◽

Ming Di

Keyword(s):

Band Gap ◽

Optical Band Gap ◽

Gap Analysis ◽

Metal Gate ◽

High K

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Abhängigkeit des optischen Bandabstandes von der molaren Zusammensetzung bei Zinksulfid-Kadmiumsulfid-Mischkristallen

Zeitschrift für Naturforschung A ◽

10.1515/zna-1969-0924 ◽

1969 ◽

Vol 24 (9) ◽

pp. 1408-1410

Author(s):

Y. Kotera ◽

T. Serine

Keyword(s):

Band Gap ◽

Optical Band Gap ◽

Linear Functions ◽

X Ray ◽

Lattice Constants ◽

Molar Composition ◽

Equimolar Composition ◽

Powder Samples ◽

Absorption Measurements

Abstract The optical band gap was determined for powder samples of (ZnxCd1-x) S by absorption measurements using a microspectrophotometer. Whereas the lattice constants (measured by X-ray lattice analysis) are linear functions of the components, the band gap is smaller than expected from the molar composition. The relation between band gap and composition was found to be linear, with a break at the equimolar composition. Possible reasons of this phenomen are discussed.

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