Synthesis and Characterization of a New [4.0.4.0] Porphyrin-like Antiaromatic Macrocycle

1997 ◽  
Vol 01 (01) ◽  
pp. 87-92 ◽  
Author(s):  
MARTIN R. JOHNSON ◽  
CARLA SLEBODNICK ◽  
JAMES A. IBERS
Keyword(s):  
Band Gap ◽  
Dmso Molecule ◽  
Geometric Optimization ◽  
Mean Deviation ◽  
Molecular Orbital Calculations ◽  
The Core ◽  
Aromatic Product ◽  
Small Band ◽  
The Mean

The antiaromatic macrocycle 2 has been prepared by the reaction of the bipyrrole dialdehyde 1 with hydrazine. In the crystal structure of 2· DMSO molecule 2 is nearly planar, the mean deviation of the 28 atoms of the core from the best least-squares plane being 0.227 Å. AM1 geometric optimization of the core of 2 leads to a fully planar macrocycle. Attempts to oxidize 2 to 3 were largely unsuccessful, yielding only limited evidence for the formation of 3. The antiaromatic precursor 2 turns out to be much more stable than the putative aromatic product 3. Molecular orbital calculations at the AM1/PM3 level indicate the S 0- T 1 gap for 3 is only about 0.2 eV and hence is readily accessible via intersystem crossing from any visible transition. This small band gap of 3 contrasts starkly with the much larger S 0- T 1 band gap of 1.86 eV calculated for 2 itself. Paratropicity in antiaromatic systems is usually attributed to a low-lying paramagnetic state, with band gaps ranging up to 2.1 eV. For the 2/3 system the S 0- T 1 band gap is substantially larger for the paratropic species than for the putative diatropic species.

scholarly journals Characterization of rifampicin-resistant Mycobacterium tuberculosis in Taiwan

2003 ◽  
Vol 52 (3) ◽  
pp. 239-245 ◽  
Author(s):  
Hsing-Yu Hwang ◽  
Chung-Yu Chang ◽  
Lin-Li Chang ◽  
Shui-Feng Chang ◽  
Ya-Hui Chang ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Core Region ◽  
Banding Patterns ◽  
The Core ◽  
Resistant Tuberculosis ◽  
Proportion Method ◽  
The Mean ◽  
Novel Alleles ◽  
The Relationship

Sixty-three rifampicin-resistant (Rifr) isolates of Mycobacterium tuberculosis from Kaohsiung, Taiwan, were analysed for mutations in the core region (69 bp, codons 511–533) of the rpoB gene. Some 84.1 % (53/63) of the resistant isolates showed mutations in this region, especially in codons 531 (41.5 %), 526 (18.9 %), 516 (15.1 %) and 533 (7.5 %). Five novel alleles of a total of 16 different types of mutations were identified in Rifr isolates. Ten Rifr isolates (15.9 %) exhibited no mutations in the core region of rpoB. Also, they did not show mutations in another 365 bp fragment (codons 99–220) of rpoB. The agar proportion method was used to determine the relationship between the degree of rifampicin resistance and alterations in the core region of rpoB. The results revealed that the mean MIC was 92.38 μg ml−1 for the 53 isolates with a mutation in the core region, whereas the mean MIC of the other 10 isolates without mutations was only 24.8 μg ml−1. This indicates that the isolates with mutations in the core region had higher levels of resistance than those without mutations in this region. IS6110 restriction fragment length polymorphism (RFLP) was used for typing of 55 Rifr M. tuberculosis isolates. Isolates contained two to 19 copies of IS6110, with sizes ranging from 600 to 16 000 bp. The majority (85 %) contained six to 16 copies. No strains lacking IS6110 were found. A total of 54 of 55 RFLP types were defined at the 90 % similarity level. The observation of varied IS6110-associated banding patterns indicates that an outbreak of drug-resistant tuberculosis did not occur in this area.

Synthesis and Characterization of Soluble and n-Dopable Poly(quinoxaline vinylene)s and Poly(pyridopyrazine vinylene)s with Relatively Small Band Gap

2002 ◽  
Vol 35 (5) ◽  
pp. 1638-1643 ◽  
Author(s):  
Maria Jonforsen ◽  
Tomas Johansson ◽  
Olle Inganäs ◽  
Mats R. Andersson
Keyword(s):  
Band Gap ◽  
Synthesis And Characterization ◽  
Small Band

Synthesis and characterization of three small band gap conjugated polymers for solar cell applications

2010 ◽  
Vol 1 (8) ◽  
pp. 1272 ◽  
Author(s):  
Stefan Hellström ◽  
Lars J. Lindgren ◽  
Yi Zhou ◽  
Fengling Zhang ◽  
Olle Inganäs ◽  
...  
Keyword(s):  
Solar Cell ◽  
Conjugated Polymers ◽  
Band Gap ◽  
Synthesis And Characterization ◽  
Small Band

MBE Growth and Characterization of Small Band Gap HgTe-HgCdTe Superlattices.

1989 ◽  
Vol 161 ◽  
Author(s):  
Y. Lansari ◽  
Z. Yang ◽  
S. Hwang ◽  
J.W. Cook ◽  
J.F. Schetzina
Keyword(s):  
Optical Properties ◽  
Band Gap ◽  
Electrical And Optical Properties ◽  
Mbe Growth ◽  
Quantum Well Structures ◽  
Barrier Layers ◽  
Small Band ◽  
Dopant Atoms ◽  
P Type

ABSTRACTA series of modulation-doped small-band-gap HgTe-Hg1−xCdxTe superlattices (SLs) have been grown by photoassisted MBE. N-type or p-type conductivity was obtained in the modulation-doped samples by incorporating either In or As dopant atoms in the barrier layers, respectively. The electrical and optical properties that these new multilayered quantum well structures display will be discussed.

Theoretical and Experimental Characterization of Small Band Gap Poly(3,4-ethylenedioxythiophene methine)s

2004 ◽  
Vol 37 (16) ◽  
pp. 5959-5964 ◽  
Author(s):  
Wen-Chang Chen ◽  
Cheng-Liang Liu ◽  
Cheng-Tyng Yen ◽  
Fu-Chuan Tsai ◽  
Christopher J. Tonzola ◽  
...  
Keyword(s):  
Band Gap ◽  
Experimental Characterization ◽  
Small Band

Growth and characterization of small band gap (∼0.6 eV) InGaAsN layers on InP

1999 ◽  
Vol 74 (9) ◽  
pp. 1287-1289 ◽  
Author(s):  
Milind R. Gokhale ◽  
Jian Wei ◽  
Hongsheng Wang ◽  
Stephen R. Forrest
Keyword(s):  
Band Gap ◽  
Small Band

DFT Benchmark Study of the O--O Bond Dissociation Energy in Peroxides Validated with High-Level Ab-Initio Calculations

2019 ◽  
Author(s):  
Danilo Carmona ◽  
Pablo Jaque ◽  
Esteban Vöhringer-Martinez
Keyword(s):  
Reference Value ◽  
Basis Set ◽  
Basis Sets ◽  
Mean Deviation ◽  
Bond Dissociation ◽  
Dissociation Energies ◽  
The Mean ◽  
Experimental Values ◽  
High Level ◽  
Almost All

<div><div><div><p>Peroxides play a central role in many chemical and biological pro- cesses such as the Fenton reaction. The relevance of these compounds lies in the low stability of the O–O bond which upon dissociation results in radical species able to initiate various chemical or biological processes. In this work, a set of 64 DFT functional-basis set combinations has been validated in terms of their capability to describe bond dissociation energies (BDE) for the O–O bond in a database of 14 ROOH peroxides for which experimental values ofBDE are available. Moreover, the electronic contributions to the BDE were obtained for four of the peroxides and the anion H2O2− at the CBS limit at CCSD(T) level with Dunning’s basis sets up to triple–ζ quality provid- ing a reference value for the hydrogen peroxide anion as a model. Almost all the functionals considered here yielded mean absolute deviations around 5.0 kcal mol−1. The smallest values were observed for the ωB97 family and the Minnesota M11 functional with a marked basis set dependence. Despite the mean deviation, order relations among BDE experimental values of peroxides were also considered. The ωB97 family was able to reproduce the relations correctly whereas other functionals presented a marked dependence on the chemical nature of the R group. Interestingly, M11 functional did not show a very good agreement with the established order despite its good performance in the mean error. The obtained results support the use of similar validation strategies for proper prediction of BDE or other molecular properties by DF Tmethods in subsequent related studies.</p></div></div></div>

Der Sommer und Herbst 2003 aus phänologischer Sicht | Summer and autumn 2003 from a phenological point of view

2004 ◽  
Vol 155 (5) ◽  
pp. 142-145 ◽  
Author(s):  
Claudio Defila
Keyword(s):  
Time Series ◽  
New Record ◽  
Point Of View ◽  
Late Spring ◽  
Mean Deviation ◽  
Leaf Shedding ◽  
The Mean ◽  
Very High ◽  
Selection Of

The record-breaking heatwave of 2003 also had an impact on the vegetation in Switzerland. To examine its influences seven phenological late spring and summer phases were evaluated together with six phases in the autumn from a selection of stations. 30% of the 122 chosen phenological time series in late spring and summer phases set a new record (earliest arrival). The proportion of very early arrivals is very high and the mean deviation from the norm is between 10 and 20 days. The situation was less extreme in autumn, where 20% of the 103 time series chosen set a new record. The majority of the phenological arrivals were found in the class «normal» but the class«very early» is still well represented. The mean precocity lies between five and twenty days. As far as the leaf shedding of the beech is concerned, there was even a slight delay of around six days. The evaluation serves to show that the heatwave of 2003 strongly influenced the phenological events of summer and spring.

Evaluation of Road Utilisation as Space For Holding Social Ceremonies in Indigenous Residential Area of Ogbomoso, Nigeria

2018 ◽  
Vol 1 (March 2018) ◽  
Author(s):  
S.A Okanlawon ◽  
O.O Odunjo ◽  
S.A Olaniyan
Keyword(s):  
Transport Infrastructure ◽  
Noisy Environment ◽  
Policy Makers ◽  
The Core ◽  
Local Roads ◽  
Strict Enforcement ◽  
The Mean ◽  
The One ◽  
The City ◽  
The Town

This study examined Residents’ evaluation of turning transport infrastructure (road) to spaces for holding social ceremonies in the indigenous residential zone of Ogbomoso, Oyo State, Nigeria. Upon stratifying the city into the three identifiable zones, the core, otherwise known as the indigenous residential zone was isolated for study. Of the twenty (20) political wards in the two local government areas of the town, fifteen (15) wards that were located in the indigenous zone constituted the study area. Respondents were selected along one out of every three (33.3%) of the Trunk — C (local) roads being the one mostly used for the purpose in the study area. The respondents were the residents, commercial motorists, commercial motorcyclists, and celebrants. Six hundred and forty-two (642) copies of questionnaire were administered and harvested on the spot. The Mean Analysis generated from the respondents’ rating of twelve perceived hazards listed in the questionnaire were then used to determine respondents’ most highly rated perceived consequences of the practice. These were noisy environment, Blockage of drainage by waste, and Endangering the life of the sick on the way to hospital; the most highly rated reasons why the practice came into being; and level of acceptability of the practice which was found to be very unacceptable in the study area. Policy makers should therefore focus their attention on strict enforcement of the law prohibiting the practice in order to ensure more cordial relationship among the citizenry, seeing citizens’ unacceptability of the practice in the study area.

Caracterização da Peneira Média em Clones de Coffea canephora

REVISTA FIMCA ◽  
2018 ◽  
Vol 5 (2) ◽  
pp. 28-31
Author(s):  
Darlan Darlan Sanches Barbosa Alves ◽  
Victor Mouzinho Spinelli ◽  
Marcos Santana Moraes ◽  
Carolina Augusto De Souza ◽  
Rodrigo da Silva Ribeiro ◽  
...  
Keyword(s):  
Genetic Improvement ◽  
Block Design ◽  
Coffea Canephora ◽  
Coffee Production ◽  
Randomized Block Design ◽  
Significant Difference ◽  
The Mean ◽  
Four Blocks ◽  
Selection Of

Introdução: O estado de Rondônia se destaca como tradicional produtor de café, sendo o segundo maior produtor brasileiro de C. canephora. No melhoramento genético de C. canephora, a seleção de plantas de elevada peneira média está associada à bebida de qualidade superior. Objetivos: O objetivo desse estudo foi avaliar a variabilidade genética de clones de C. canephora para o tamanho dos grãos, mensurado a partir da avaliação da peneira média (PM). Materiais e Métodos: Para isso, foi conduzido ao longo de dois anos agrícolas experimento no campo experimental da Embrapa no município de Ouro Preto do Oeste-RO, para a avaliação da peneira média de 130 genótipos (clones) com características das variedades botânicas Conilon, Robusta e híbridos intervarietais. O delineamento experimental utilizado foi de blocos ao acaso, com quatro repetições de quatro plantas por parcela. Resultados: Não houve resultados significativos para a interação clones X anos, indicando uma maior consistência no comportamento das plantas ao longo do tempo. Porém foram observadas diferenças significativas para o tamanho dos grãos entre os genótipos avaliados, possibilitando selecionar genótipos superiores. Conclusão: Os genótipos agruparam-se em cinco classes de acordo com o teste de média, subsidiando a caracterização de um gradiente de variabilidade da característica avaliada ABSTRACTIntroduction: Coffea canephora accounts for approximately 35% of the world's coffee production. The state of Rondônia stands out as a traditional coffee producer, being the second largest Brazilian producer of C. canephora. In the classical genetic improvement of C. anephora, the selection of plants of high average sieve is associated with a drink of superior quality. Objectives: The objective of this udy was to evaluate the genetic variability of Coffea canephora clones for the agronomic medium sieve (PM). Materials and Methods: The experiment was conducted in the experimental field of Embrapa, municipality of OuroPreto do Oeste-RO, located at coordinates 10º44'53 "S and 62º12'57". One hundred thirty genotypes (clones) of botanical characteristics Conilon, Robusta and intervarietal hybrids were evaluated in the agricultural years 2013-2014 and 2014-2015. The experimental design was a randomized block design with four blocks and four plants per plot, spacing 3.5 x 1.5 meters between plants. Results: Significant difference was found for the grain size. According to the F test, at 5% probability, the genotypes were grouped into five classes according to the mean test. Conclusion: The results obtained subsidized the characterization of a variability gradient of the evaluated trait.

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