Character Index Research Articles

The response of East Kalimantan, Indonesia local rice cultivars against iron stress

Nurhasanah, lestari HS, Sunaryo W. 2019. The response of East Kalimantan, Indonesia local rice cultivars against iron stress. Biodiversitas 20: 273-282. Iron (Fe) toxicity is one of the most problematic metal elements in acidic soil. Besides being as an essential micronutrient, an excessive iron can cause mineral and nutrients absorption disorder which leads to disruption of plant metabolism and cell development. Reduction of plant growth and yield will be the further consequences of the excessive soil iron content. This study aimed to evaluate the response of East Kalimantan local rice cultivars and to screen rice genotypes tolerant to iron stress. Twenty-five rice genotypes were used in this study, consisted of twenty-three local rice cultivars of East Kalimantan and two control of iron sensitive (IR64) and tolerant (Mekongga) varieties. Uniform sprouts (3 days old) having 1-1.5 cm root length were used for iron stress experiment. The seedlings were grown in nutrient solution using hydroponic system in an aerobic condition. The seedlings were treated for one week in iron stress condition by adding an extra iron source of 100 and 200 ppm FeSO4.7H2O (pH 4.0). The seedlings grown in the nutrient solution without an extra iron treatment at normal acidity growth condition (pH 5.8) were used as the control. The growth responses were observed from root, shoot, and biomass of the plants. The tolerance index of the plant growth characters was calculated to classify the rice genotypes into tolerant, moderate, and sensitive to iron stress. The results showed that 100 and 200 ppm of FeSO4.7H2O treatments inhibited the root and shoot growth and also reduced the plant biomass. The plant growth reduction was in parallel with the increase of iron concentration. There was a significant differential response of East Kalimantan local rice genotypes to iron stress treatment. Some genotypes showed an extreme reduction of plant growth, whereas several genotypes had an increased growth under stressed situation. In the contrary, the sensitive genotype IR 64 was consistently sensitive based on the tolerance index of the root, shoot, and plant biomass characters. Among all growth parameters, the most selective character for iron toxicity screening was maximal root length character. This character caused the most severe symptoms for most of the genotypes. Two local rice genotypes, Bentian and Bogor Hitam, were consistently tolerant based on the maximal root growth, total root growth, shoot length and plant biomass.

AMPKα pathway involved in hepatic triglyceride metabolism disorder in diet-induced obesity mice following Escherichia coli Infection.

To investigate the different effects of acute pulmonary infection induced by Escherichia coli (E. coli) on lipid metabolism between diet-induced obesity (DIO, fed with high-fat diet) mice and lean mice. A total of 180 ICR mice were selected to be challenged intranasally with phosphate-buffered saline or 109 CFUs/mL of E. coli, and the body character indexes, biochemical indexes and expressions of genes and proteins involved in lipid metabolism were examined pre- and post-infection. Results revealed that, before infection, DIO mice had significantly higher body weight, adipose and liver indexes, free fatty acid and triglyceride contents than lean mice. After infection, increased free fatty acid and triglyceride contents, increased expressions of resistin, SREBP-1c, ACC1, FAS and SCD-1, and declined PPARα, CPT-1α expressions and AMPKα phosphorylation were detected in the infected group, while the change rates were more serious in the lean mice than the DIO mice. The above-mentioned findings verified that, after being infected with E. coli, hepatic lipid metabolism disorder was aggravated by activating SREBP-1c related lipid synthesis pathway and inhibiting PPARα related fatty acid oxidation pathway. However, infection-induced lipid metabolic disorders was slighter in the DIO mice than the lean mice through AMPKα pathway.

Study on phenotypic diversity and cluster analysis of Cistanche Herba in different populations in Xinjiang

To intuitively understand the phenotypic diversity of intra-population and inter-population of the medicinal Cistanche Herba distributed in Xinjiang province, three species of Cistanche Herba were selected for the first time to be conducted to phenotypic observation and measurement from the morphological perspective, aiming to fill the gap in the morphological research concerning Cistanche Herba, and discuss about the relationship between the phenotypic variation and the host plants together with the geographical conditions, thus better understanding the speciation and evolutionary mechanism of Cistanche Herba and providing some scientific basis for the resource protection and germplasm breeding of Cistanche Herba. Based on sampling survey, a total of 118 well grown medicinal Cistanche samples from 17 Cistanche Herba distribution areas in Xinjiang province were selected, and various indexes were observed and measured. Besides, ANOVA and clustering analysis were conducted with 9 phenotypic quantity characters. The Cistanche Herba was plentiful in phenotypic variation. For detail, significant intra-population differences were observed in eight of the nine character indexes, and the intra-population differences were more obvious than those of inter-population. For each quantity character of the three species, the flower density possessed the maximal variable coefficient (71.1%) while the flower length was the minimum (15.9%). The phenotypic variation was also obvious among different populations. Specifically, the average variable coefficient of flower number was the maximal one (46.5%) and the flower length was the minimum one (10.0%). For different populations, the average variable coefficient of the D4 population was the maximal one (41.1%) and the S3 population was the minimum one (13.5%). According to the clustering analysis, all the samples of Cistanche Herba could be divided into three groups when the Euclidean distance was set at 15. The populations of S1, S3, D1, S2, D4, D6, D7 and D5 which distributed in the north of Xinjiang were clustered into one group, and the populations of D8, S4, D9, D2 and D3 that grown in east and central of Xinjiang were clustered into another group. The populations of C. deserticola and C. salsa could not be completely separated, but both of them were obviously differentiated from the T1, T3 and T2 populations of C. tubulosa. Besides, the C. deserticola and C. salsa displayed a patch distribution among different populations, and similar phenotypic characters were shared for each population. The research results of phenotype were consistent with that of molecular biology study of Cistanche Herba. The different phenotypic characters in different distribution areas were deduced to be arose from geographical isolation caused by mountains, which led to the specific genetic structure for each population of Cistanche Herba during the long-term adaptation and evolution. In conclusion, the current study showed the adaptation potency of Cistanche Herba exposed to different habitats.

Optimization of the working cycle of a transport diesel engine by simulating the combustion process with a double Wiebe function

For modeling the working cycle of transport diesels, models with two laws of combustion according to the Wiebe, mathematically related to each other and corresponding to the initial and main periods of the process, are increasingly being used. However, known mathematical models give different results in estimating the distribution of fuel shares between these periods. These models also do not allow to simulate a smooth start of the combustion process. Therefore, a new mathematical model was developed for calculating the working cycle of a diesel engine with two independent laws of combustion of fuel, described by the functions of Wiebe. Communication between them is carried out through a new parameter, which is the proportion of fuel, burning in the initial period, from the total cyclic feed. The novelty of the model is also the ability to set, within a wide range, independently of each other, the angles of the start and duration of the first and second combustion laws for the initial and base periods, respectively. A program for calculating the operating cycle with simulation of the combustion process using a new mathematical model is developed. Calculations have been made for a transport diesel engine equipped with a fuel-supply system of a battery type. The results of the calculation showed that an increase in the fraction of the fuel burned according to the first law from 0.1 to ~ 0.3 with other parameters being constant leads to a significant increase in the maximum pressure in the diesel cylinder and some improvement in the indicator indexes. With a further increase in the fuel fraction to 0.5, the maximum gas pressure continues to increase, and the indicator indexes slightly deteriorate. At the same time, in the initial period, the value of the index of the combustion character has practically no effect on the indicator index of the diesel engine and the maximum pressure in the cylinder. In the main period, the value of the indicator of the nature of combustion, on the contrary, significantly affects the indicator indexes of the diesel engine and the maximum pressure in the cylinder. The calculation determines the optimal heat release law in the diesel cylinder of ChN15/16 type, which provides the best indicator values when the maximum pressure in the cylinder is limited.

Development of the Character Index Instrument for Engineering College Students

Development of the Character Index Instrument for Engineering College Students

Impacts of exogenous pollutant bisphenol A on characteristics of soybeans

Bisphenol A (BPA) is an endocrine disruptor that is ubiquitous in the environment. Previous studies have focused on the effects of BPA on plants to assess the ecological risk of BPA in the environment. To evaluate the effects of BPA on plant biological characters more systematically, we investigated the biological characters of above-ground and under-ground organs of soybean plants exposed to BPA. Meanwhile, the mechanisms for the observed changes were also analyzed from the view of hormone levels and photosynthesis. The results showed that after exposure to 0.8 mg L−1 BPA for three days, indole-3-acetic acid (IAA) and gibberellic acid levels in roots increased significantly, and the IAA level increased in leaves, so the character indices of roots and leaves both increased. The IAA and ethylene levels in stems increased, but the character indices of stems did not increased. With higher BPA concentrations, especially exposure to 17.2 mg L−1 BPA, the levels of IAA, gibberellic acid, and zeatin decreased (except for the increased zeatin in leaves), and abscisic acid and ethylene levels increased; thus, all of the character indices significantly decreased. By comparing the changes in various biological characters, we found that leaf area, root surface area, and root length changed most significantly. In addition, changes in photosynthetic parameters provided initial causes for plant growth changes, and impacted biological characters. The changes of character indices were stronger when the BPA exposure time was prolonged, and after the removal of BPA, the character indices showed some recovery. Therefore, BPA exposure can regulate the changes in plant characters by influencing hormone levels and photosynthesis, and root surface area, root length, and leaf area were the most sensitive to BPA.

Exclusiveness and Inclusiveness in the British National Identity

The issue of identity has been a fundamental one in virtually all human societies. The binary questions “who are we?” and “who are not we?” are constitutive of the meaning of any identity formation. Identity is an elusive concept that generates more questions than answers. Multifarious challenges face identity formation and consolidation which makes those two processes hard multidimensional tasks. In Britain, the concept of identity is central given the complex multinational and multicultural character of the nation. In their contact with different nations and peoples (the imperial experience), the British found themselves constantly negotiating their identity. They defined themselves with what they are and with what they are not as well. The British national identity or what is widely known as Britishness, has been a fuzzy and a difficult-to-define concept. It has been defined in different ways by different political sociologists each focusing on a distinctive aspect of the concept according to one’s perspective. It is a legal and political notion for politicians, an important cohesive concept for sociologists and a major source of identity for cultural critics. However, we propose in this article to broach the concept from an historical race-related perspective. We argue that the concept has been a useful index of the changing character of post-war race-related British politics. Historically, British race politics can roughly be divided into two major phases: the Assimilationist phase (starting from 1945 till the end 1970’s) and Multicultural phase (1980 till now). The assimilationist Britishness was based on a racial definition that excluded the different “other” (the alien, the immigrant) whereas the multicultural Britishness has been more tolerant and inclusive of difference. This article attempts to trace the ups and downs of the British national identity (Britishness) within the context of contemporary multicultural British society. This allows us to show how the same concept is capable of excluding and including the same set of ideological assumptions according to changes in the “structure of feeling” of those who believe in it.

Development of Technology･Home Economics teaching-learning plans using ARCS strategies to improve character for middle school students: Focusing on the unit of ‘Understanding families’

본 연구의 목적은 기술･가정과의 인성교육 실현을 위해 ARCS 동기유발 전략을 적용한 인성교육 교수･학습 과정안을 개발하여 수업을 실시한 후, 가정과 수업이 청소년의 인성변화에 긍정적인 영향을 미치는지 그 효과를 분석하는데 있다. 수업은 광주광역시에 위치한 M중학교의 남학생 4학급 110명을 대상으로 2017년 3월 6일부터 4월 7일까지 총 5주간 9차시의 인성교육 수업이 실시되었다. 또한 학습자의 수업 평가, 수업 전･후 인성수준 평가를 통해 수업의 효과를 살펴보았다. 본 연구의 단계 및 결과를 요약하면 다음과 같다. 첫째, ‘가족의 이해’ 단원의 인성교육 수업을 위하여 9차시의 교수･학습 과정안이 개발되었다. 본 교수･학습 과정안은 ARCS 동기유발 전략을 적용하여 학습자의 학습 흥미도를 높이고 인성요소를 고려하여 중학생의 인성을 향상하기 위한 것이다. 교수･학습을 위해 중학교 기술･가정 ‘가족의 이해’ 단원에서 총 9차시의 교수･학습 과정안을 개발하고, 활동지(14), PPT자료(2)를 개발하였다. 둘째, ARCS 동기유발 전략을 적용한 인성교육 수업을 받은 중학생은 인성의 하위 항목 (성실, 배려･소통, 책임, 자기조절, 정직･용기, 지혜, 정의) 모두에서 유의한 차이가 나타났다. 따라서 ARCS를 적용한 인성교육 수업은 중학생의 인성을 함양하는데 긍정적 효과를 보였다고 할 수 있다. 셋째, ARCS 동기유발 전략을 적용한 인성교육 수업은 학습자의 수업의 만족도를 높여주었다. 척도형 설문조사를 실시한 결과 수업에 대한 전반적인 평가 4개의 문항에서 72.3%가 ‘매우 그렇다’로 응답하였다. 좋았던 점과 아쉬웠던 점을 묻는 개방형 질문에는 ‘재미있었고, 가족에 대해 더 잘 알 수 있었고 조 활동이 많아 배려와 협동심이 늘어날 수 있어 좋았다.’ 등의 응답으로 학습자들이 인성교육 수업에 즐겁게 참여하였다는 것을 알 수 있었다. 단 필기내용이 많아 힘들어 하는 학생들이 있으므로 좀 더 효율적인 지도 방안을 모색할 필요가 있다. 개발된 ARCS 동기유발 전략을 적용한 기술･가정과 인성교육 교수･학습 과정안과 학습 자료는 학생들의 인성 역량을 강화하는 기초 자료로 활용이 되길 기대한다.The purposes of this study were to develop and apply teaching-learning plans using ARCS strategies to improve character of middle school students and analyze whether a home economics class helps to give positive effects on youth character change. Nine-period classes were conducted for 110 male students in 4 classes of M middle school in Gwangju metropolitan city for 5 weeks from March 6 through April 7 in 2017. The effectiveness of classes were examined with learnersʼ class assessment and pre- and post- character index test. The research steps and results in this study are as follows. First, the teaching-learning plans for 9 periods were developed for the character education class of the chapter ʻUnderstanding familiesʼ. These teaching and learning course plans were designed to enhance learnerʼs interests in learning using ARCS motivational strategy and improve character of middle school students in consideration of character elements. In the chapter ʻUnderstanding familiesʼ of Technology･Home Economics in middle school, the teaching-learning plans for 9 periods, 14 student activity sheets, and 2 powerpoint materials for teaching and learning were developed. Second, students who had the character education classes using ARCS motivational strategy showed significant differences in all character elements. Therefore, the character education class using ARCS shows positive effects to build up character of middle school students. Third, the character education classes using ARCS motivational strategy increased the class satisfaction of learners. The character education class teaching and learning course plans and learning materials in Technology･Home Economics using ARCS motivational strategy will be used as a basic resource to build up studentsʼ character in the future.

High-strength charcoal briquette preparation from hydrothermal pretreated biomass wastes

The waste cotton stalk (CS) and wood sawdust (WS) biomass samples pretreated by two different thermal methods (dry torrefaction (DT) and hydrothermal treatment (HT) at 200, 230, 260°C, respectively) were densified to prepare biomass briquette and then carbonized at 400°C to prepare charcoal briquette without any binders. The physical properties and combustion characteristics of the derived charcoal briquettes were investigated to assess the feasibility of its application as barbecue charcoal. The results indicate that the physical properties including the mass densities and compressive strengths of HT charcoal briquettes are better than those of DT and unpretreated charcoal briquettes, even those of the commercial barbecue charcoal with binder addition. Moreover, the fixed carbon and ash yields of the resulted HT charcoal briquettes meet the European Standard on commercial barbecue charcoal. Especially HT charcoal briquettes has far lower ash yield than the commercial barbecue charcoal. HT charcoal briquettes have similar combustion character index (S) with the commercial barbecue charcoal. In the research, CS and WS hydrothermal pretreated at 230°C are the best materials for the charcoal briquette preparation process.

LETTY GARTH'S LITTLE RED BOOK: “RUMPELSTILTSKIN,” REALISM, ANDMIDDLEMARCH

Letty Garth's “favourite red volume”makes its appearance inMiddlemarchat the beginning of Book 7, at the Vincy's New Year's Day party that draws most of the Middlemarch town characters together. It is a small passage that can easily go unnoticed – or, if registered at all, glossed as simply part of the fabric of dense, inconsequential details that realist texts deploy to produce verisimilitude. Roland Barthes describes such details as potentially “scandalous” from the point of view of structure in that they seem to amount to “a kind of narrativeluxury,” likely to threaten structural coherence, recoverable at best as “filling” or as giving “some index of character or atmosphere” (141). Such details might be said to reinforce the vices of nineteenth-century realism, including closing the gap between words and things: “we are the real,” these details say, producing “thereferential illusion” (148). They amount to bad narrative housekeeping, “increasing the cost of narrative information” (141). Since the detail of Letty's book involves a young child it is doubly likely, in a novel so clearly dedicated to the adult world of compromise and doubtful success, to be set aside as mere local colour. The potentially trivializing function of the paradox of small instances of excess is reflected in Barthes’ descriptive phrases for them: “useless details,” “insignificant notation” (142).

Thienylquinonoidal Porphyrins and Hexaphyrins with Singlet Diradical Ground States.

To explore stable organic diradicaloids, meso-thienylquinonoid-substituted porphyrins Pn and hexaphyrins Hn, where "n" denotes the number of thienyl units in the meso-substituents, were synthesized. P0 was identified as a closed-shell quinonoid, whereas P1 was shown to possess significant diradical character with diradical character index (y) of 0.99 and quite small singlet-triplet energy gap (ΔES-T ) of -0.13 kcal mol-1 . P1 was certainly stable, allowing its isolation, but decomposed gradually in solution. In the hexaphyrin series, it was shown that H0 and H1 were closed-shell quinonoids, but H2 was a highly stable diradicaloid with y=0.85 and ΔES-T of -3.72 kcal mol-1 . The high stability of H2 was ascribed to effective spin delocalization over the entire conjugated network. Characteristically, H2 displays an intense absorption band in NIR region at λmax =1175 nm with molar absorption coefficient (ϵ) of 8.81×104 mol-1 L cm-1 , a narrow HOMO-LUMO gap of 0.69 eV, and nine reversible redox potential waves.

Selection of indigenous Lactobacillus paracasei CD4 and Lactobacillus gastricus BTM 7 as probiotic: assessment of traits combined with principal component analysis.

The population of the Himalayan region is known to consume a variety of fermented and nonfermented foods and as a result they have been benefited in terms of overall health, because of the associated beneficial microbes. Therefore, the focus of the present study was to identify new strains of lactic acid bacteria (LAB) from dairy products such as milk (cow, goat, buffalo) and fermented products (curd and buttermilk) with properties suitable for use as probiotic cultures. A total of 75 isolates tentatively identified as LAB from 100 samples were initially screened for production of β-haemolysin as indicators of virulence which resulted in 38 isolates with no haemolytic activity. Further subtractive screening based on resistance to gastrointestinal tract barriers (acid and bile salts) resulted in the selection of the eight most promising strains. All these eight strains were resistant to pH 2·0, 1% bile concentration and pancreatin (1mgl-1 ). Among the eight isolates, three isolates were identified as Brevibacillus thermoruber and the others as Brevibacillus aydinogluensis, Lactobacillus gastricus, L. paracasei, Enterococcus sp. Weisella confusa based on 16S rDNA region. Among these isolates, L. paracasei CD4 and L. gastricus BTM7 indicated maximum tolerance to simulated gastric environment. Both the isolates possessed highest score for cell surface hydrophobicity, cell autoaggregation, adherence to Caco-2 cell lines and antimicrobial activity against clinical isolates of Escherichia coli and Shigella sp. comparable to standard strain of Lactobacillus rhamnosus GG. Further principal component analysis and clustering analysis based on Euclidean Similarity index of probiotic characters revealed that L. paracasei strain CD4 and L. gastricus strain BTM7 were placed closest to reference strain L. rhamnosus GG and were therefore identified as most promising probiotic candidate cultures. These characteristics suggest that these strains could be excellent candidates for probiotics. Milk-based products serve as reservoir for bacterial species with probiotic attributes.

Effects of rainfall regime and its character indices on soil loss at loessial hillslope with ephemeral gully

Understanding the relationship between hillslope soil loss with ephemeral gully and rainfall regime is important for soil loss prediction and erosion control. Based on 12-year field observation data, this paper quantified the rainfall regime impacts on soil loss at loessial hillslope with ephemeral gully. According to three rainfall parameters including precipitation (P), rainfall duration (t), and maximum 30-minute rainfall intensity (I30), 115 rainfall events were classified by using K-mean clustering method and Discriminant Analysis. The results showed that 115 rainfall events could be divided into three rainfall regimes. Rainfall Regime 1 (RR1) had large I30 values with low precipitation and short duration, while the three rainfall parameters of Rainfall Regime 3 (RR3) were inversely different compared with those of RR1; for Rainfall Regime 2 (RR2), the precipitation, duration and I30 values were all between those of RR1 and RR3. Compared with RR2 and RR3, RR1 was the dominant rainfall regime for causing soil loss at the loessial hillslope with ephemeral gully, especially for causing extreme soil loss events. PI30 (Product of P and I30) was selected as the key index of rainfall characteristics to fit soil loss equations. Two sets of linear regression equations between soil loss and PI30 with and without rainfall regime classification were fitted. Compared with the equation without rainfall regime classification, the cross validation results of the equations with rainfall regime classification was satisfactory. These results indicated that rainfall regime classification could not only depict rainfall characteristics precisely, but also improve soil loss equation prediction accuracy at loessial hillslope with ephemeral gully.

Character-based indexing and browsing with movie ontology1

Various content-based methods (e.g., audio-visual feature recognition and dialogs analysis) have been proposed for analyzing, indexing and understanding movies. Our previous approach introduced a method for character indexing based on manual annotation. However, this method has shown several unsati sfactoriness on performing of indexing. For addressing this issue, in this work, we take into account using image processing techniques for semi-automatically character-based indexing. Besides, a movie ontological model is created for connecting character appearances and character’s roles in the movie. Moreover, we propose a system for assist user indexing manually. On the other hand, a searching and browsing tool is also introduced. Using this tool, user can query character-based semantic indexing. Experimental results are shown that our proposed method is able to assist user in consuming index time and providing a method for automatic indexing, searching and browsing based on semantic queries.

Effects of different forest stand types of Pinus sylvestris var. mongolica on insect community diversity in Saihanba Nature Reserve, North China

In order to study the effects of different stand types of Mongolian scots pine (Pinus sylvestris var. mongolica) on the diversity of insect community in the plantation under close-to-nature forest management, the structure of the insect community was studied in five stand types of the Mongolian scots pine pure forest and mixed forests in Saihanba Nature Reserve. The insects were collected by the sweep net method, and the diversity index, similarity, principal component, and stability of insect communities in different forest types were analyzed. In total, 9617 insects, belonging to 7 orders, 70 families, 195 species, were collected, and the Diptera, Hemipteran and Coleopteran were the dominant groups. The insect species in 5 stand types were all rich, and the insect community structure among the different stands reached a moderate dissimilar level. The species and individual number of mixed forest was more than those of pure forest. There was no significant difference among different stand types in insect community character indices. Principal component analysis indicated that phytophagous group, predatory group and parasitic group in each stand type were the main factors influencing the community structure, and predatory group and parasitic group had a stronger control effect on phytophagous group. The structure of insect community in the diffe-rent forest stand types had relatively high stability.

A Study on Development and Validation of Character Index Instrument for College Students

A Study on Development and Validation of Character Index Instrument for College Students

가해자 집단의 인성 특징에 따른괴롭힘 역할 성향 및 인성교육의 효과성 차이

가해자 집단의 인성 특징에 따른괴롭힘 역할 성향 및 인성교육의 효과성 차이

Index of Chinese Characters for “Repertoire Is Technique: Programming Transmission at a Xiqu Festival”

Index of Chinese Characters for “Repertoire Is Technique: Programming Transmission at a Xiqu Festival”

Artykuł recenzyjny książki Andrzeja Maksymiliana Fredro Scriptorum Seu Togae et Belli Notationum Fragmenta. Accesserunt Peristromata Regnum. Symbolis Expressa

<p>Autor omawia idee polityczne Andrzeja Maksymiliana Fredry. Ocenie podlega obszerny wstęp napisany współcześnie przez Marka Tracza Trynieckiego. Wskazuje się na prezentowanie przez Fredrę modelu monarchii umiarkowanej. Podkreśla się zerwanie komentatora z dotychczasowymi stereotypami i analizami piśmiennictwa A.M. Fredry dokonanymi w okresie wcześniejszym. Odrębnym problemem jest ukazanie poglądów pisarza na temat relacji państwo – kościół, zadań edukacji patriotycznej czy problemu wojska i wojny.</p>

Benzo-thia-fused [n]thienoacenequinodimethanes with small to moderate diradical characters: the role of pro-aromaticity versus anti-aromaticity.

Open-shell singlet diradicaloids have recently received much attention due to their unique optical, electronic and magnetic properties and promising applications in materials science. Among various diradicaloids, quinoidal π-conjugated molecules have become the prevailing design. However, the need for a fundamental understanding on how the fusion mode and pro-aromaticity/anti-aromaticity affect their diradical character and physical properties remains unaddressed. In this work, a series of pro-aromatic benzo-thia-fused [n]thienoacenequinodimethanes (Thn-TIPS (n = 1-3) and BDTh-TIPS) were synthesized and compared with the previously reported anti-aromatic bisindeno-[n]thienoacenes (Sn-TIPS, n = 1-4). The ground-state geometric and electronic structures of these new quinoidal molecules were systematically investigated by X-ray crystallographic analysis, variable temperature NMR, ESR, SQUID, Raman, and electronic absorption spectroscopy, assisted by DFT calculations. It was found that the diradical character index (y0) increased from nearly zero for Th1-TIPS to 2.4% for Th2-TIPS, 18.2% for Th3-TIPS, and 38.2% for BDTh-TIPS, due to the enhanced aromatic stabilization. Consequently, with the extension of molecular size, the one-photon absorption spectra are gradually red-shifted, the two-photon absorption (TPA) cross section values increase, and the singlet excited state lifetimes decrease. By comparison with the corresponding anti-aromatic analogues Sn-TIPS (n = 1-3), the pro-aromatic Thn-TIPS (n = 1-3) exhibit larger diradical character, longer singlet excited state lifetime and larger TPA cross section value. At the same time, they display distinctively different electronic absorption spectra and improved electrochemical amphotericity. Spectroelectrochemical studies revealed a good linear relationship between the optical energy gaps and the molecular length in the neutral, radical cationic and dicationic forms. Our research work discloses a significant difference between the pro-aromatic and anti-aromatic quinoidal compounds and provides guidance for the design of new diradicaloids with desirable properties.