An Agenda-Setting Account for Psychological Typhoon Eye Effect on Responses to the Outbreak of COVID-19 in Wuhan.

During the outbreak of COVID-19 in Wuhan in 2020, we conducted a nationwide survey of 8170 respondents from 31 provinces/municipalities in China via Sojump to examine the relationship between the distance to respondents' city of residence from Wuhan and their safety concerns and risk perception of the epidemic that occurred in Wuhan City. We found that (1) the farther (psychologically or physically) people were from Wuhan, the more concerned they were with the safety of the epidemic risk in Wuhan, which we dubbed the psychological typhoon eye (PTE) effect on responses to the outbreak of COVID-19; (2) agenda setting can provide a principled account for such effect: the risk information proportion mediated the PTE effect. The theoretical and managerial implications for the PTE effect and public opinion disposal were discussed, and agenda setting was identified to be responsible for the preventable overestimated risk perception.

Long-term orientation and demographics predict the willingness to quarantine: A cross-national survey in the first round of COVID-19 lockdown.

To be or not to be quarantined? That is the question posed by COVID-19 pandemic to almost every resident in the world. Approximately three months after the first application of the COVID-19 lockdown to residents in 17 Asian, African, European, American, and Oceanian countries, we carried out a cross-national survey of 26,266 residents via online platforms such as Sojump and Prolific to investigate their willingness to quarantine and its influencing factors. Findings show that 1) The willingness to quarantine is low in countries with high long-term orientation; 2) Females are more willing to be quarantined than males; 3) Gender difference on willingness to quarantine is large among people with older age and low education. Theoretical and managerial implications are discussed. Understanding how culture and demographics affect people's willingness to quarantine not only provides insight into how to respond to the current pandemic, but also helps the world prepare for future crises.

Which Information Frame is Best for Reporting News on the COVID-19 Pandemic? An Online Questionnaire Study in China.

INTRODUCTION: The COVID-19 pandemic has received broad public attention and has been subject to social media discussion since the beginning of 2020. Previous research has demonstrated that framing could influence perception and behaviors of audience members in the mass media. The question addressed in this paper concerns which information frame is best for reporting negative news (eg, deaths) and positive news (eg, recoveries or cures) related to the outbreak of COVID-19. METHODS: During the Spring Festival holidays of 2020 in China, we investigated a sample of 8170 participants' risk perceptions and emotional responses to the pandemic, and their willingness to forward updates when the information is presented in different frames by using a 2 (domain: living [good news] vs dying [bad news]) × 2 (count: absolute vs relative) × 2 (population base: excluding population base vs including population base) × 2 (content: text-only vs text-plus-graphic) mixed factorial design, with the first factor being a within-subjects factor and the last three being between-subjects factors. RESULTS: Results indicated that (1) participants were more willing to forward good news (eg, cures) than bad news (eg, deaths); (2) when reporting bad news, the inclusion of the "population base" was effective in minimizing negative emotions; (3) when reporting good news, excluding the "population base" was more effective than including it in order to maximize positive emotions; (4) a text-plus-graphic frame worked better than a text-only frame in lowering the level of risk perception and negative emotions. DISCUSSION: This study is relevant to how individuals and organizations communicate information about this viral pandemic and the probable impact of this news on the general public.

Association between breast cancer and thyroid cancer: A study based on 13 978 patients with breast cancer.

BACKGROUND: Thyroid cancer (TC) is one of the most commonly seen secondary malignancy in breast cancer (BC) survivors. MATERIALS AND METHODS: A retrospective study was conducted in BC patients in our center from 1999 to 2013. Patients were divided into BC-TC group and BC-alone group. RESULTS: In total, 13 978 BC patients were identified, among whom 247 (1.8%) had TC. The standardized incidence ratio (SIR) of TC was 4.48 compared with Chinese females, and up to 98.0% of cases were thyroid papillary carcinomas. A family history of malignancy was the only independent risk factor (odds ratio = 1.457, P = 0.025) for development of TC in patients with BC. We also identified inferior survival in patients with synchronous versus metachronous BC-TC (P = 0.016). Synchronous BC-TC (risk ratio = 5.597, P = 0.018) was an independent prognostic factor for inferior RFS. CONCLUSIONS: We observed high co-occurrence of TC in patients with BC. There might be different mechanisms behind synchronous and metachronous BC-TC.

Serum glycated albumin, glycated hemoglobin, and arterial stiffness in a general Chinese population.

BACKGROUND: Both glycated albumin (GA) and glycated hemoglobin (HbA1c) reflect the mean glucose levels. This study was conducted to investigate the relationships among GA, HbA1c, and arterial stiffness in the general population. METHODS: A total of 11,014 participants were included. Serum GA; HbA1c; and arterial stiffness indices, including brachial-ankle pulse wave velocity (baPWV) and central systolic blood pressure (cSBP), were measured. Single-factor and multivariate regression analyses were performed. Receiver operating characteristic (ROC) analysis was performed to compare the predictive value of GA, HbA1c, and their combination for arterial stiffness. All analyses were stratified by sex. RESULTS: Men had a lower GA level than women. GA, HbA1c, and plasma glucose levels were correlated. The levels of baPWV and cSBP increased across sex-specific quartiles of GA and HbA1c (P for trend<0.001 for all). Both GA and HbA1c were positively related to elevated baPWV and cSBP after adjusting for conventional factors (P<0.05 for all). These relationships remained significant when participants were divided into groups with normal glucose tolerance, prediabetes, or diabetes. Regarding screening for elevated baPWV and cSBP, the values of the area under the ROC curve (AUC) for GA were similar to those for HbA1c in men but were lower than those for HbA1c in women. The combination of GA and HbA1c did not improve the AUC compared with HbA1c alone. CONCLUSIONS: Both GA and HbA1c were associated with arterial stiffness. The predictive value of GA for arterial stiffness was similar in men but lower in women compared with that of HbA1c.

[Qilin Pills for idiopathic oligoasthenospermia: A multi-centered randomized double-blind controlled clinical trial].

OBJECTIVE: To evaluate the clinical efficacy and safety of Qilin Pills in the treatment of oligoasthenospermia in infertile men. METHODS: This multi-centered randomized double-blind controlled clinical trial included 216 infertile males with oligoasthenospermia, 108 in the trial group and the other 108 in the control, the former treated with Qilin Pills at the dose of 6 g tid while the latter with Wuziyanzong Pills at 6 g bid, both for 12 weeks. We examined the total sperm count, sperm motility and the count of progressively motile sperm of the patients before and at 4, 8 and 12 weeks after medication and evaluated the safety of the drug based on the adverse events and the laboratory results of blood and urine routine examinations and liver and kidney function tests. RESULTS: Compared with the baseline, the patients in the trial group showed a significant time-dependent improvement after 4, 8 and 12 weeks of medication in sperm motility (21.75% vs 27.54%, 29.04% and 32.95%, P <0.05), total sperm count (156.27 ×106 vs 177.33, 188.18 and 205.44 ×106, P <0.05), and the count of progressively motile sperm (32.08 ×106/ml vs 46.33, 50.98 and 61.10 ×106/ml, P <0.05). The three parameters above were also improved in the controls, but more significantly in the trial group (P <0.05). CONCLUSIONS: Qilin Pills can evidently improve the semen quality of oligoasthenospermia patients with no obvious adverse events.

[Efficacy of alpha-lipoic acid combined with tamoxifen citrate in the treatment of oligoasthenospermia].

OBJECTIVE: To investigate the effect of alpha-lipoic acid (α-LA) combined with tamoxifen citrate (TC) in the treatment of oligoasthenospermia. METHODS: From June to November 2016, we treated 60 patients with oligoasthenospermia in our Department of Andrology, 30 (the trial group) with oral α-LA (0.6 g, qd) + TC (20 mg, qd) and the other 30 (the control group) with oral L-carnitine (1g, bid) + TC (20 mg, qd). Before and after 3 months of medication, we examined the semen parameters of the patients and the levels of their seminal oxidative stress biomarkers, including methylenedioxyamphetamine (MDA) and total antioxidant capacity (TAC) in the seminal plasma. We also compared the pregnancy rate and adverse reactions between the two groups. RESULTS: Totally, 57 of the patients completed the treatment, 28 in the trial group and 29 in the control. Compared with the baseline, the patients of the trial group showed significant improvement after 3 months of medication in the semen volume (ï¼»2.50 ± 0.71ï¼½ vs ï¼»3.37 ± 0.70ï¼½ ml, P <0.05), sperm concentration (ï¼»12.00 ± 1.65ï¼½ vs ï¼»19.34 ± 2.04ï¼½ ×106/ml, P <0.05), percentage of progressively motile sperm (PMS) (ï¼»18.01 ± 3.01ï¼½% vs ï¼»35.41 ± 6.49ï¼½%, P<0.05), MDA level (ï¼»14.96 ± 2.76ï¼½ vs ï¼»10.04 ± 1.04ï¼½ nmol/ml, P <0.05), and TAC in the seminal plasma (ï¼»9.83 ± 1.02ï¼½ vs ï¼»12.25 ± 1.11ï¼½ U/ml, P <0.05), and so did the controls in the semen volume (ï¼»2.76 ± 0.67ï¼½ vs ï¼»3.36 ± 0.93ï¼½ ml, P <0.05), sperm concentration (ï¼»11.47 ± 1.10ï¼½ vs ï¼»17.77 ± 3.56ï¼½ ×106/ml, P <0.05), percentage of PMS (ï¼»19.22 ± 1.41ï¼½ vs ï¼»36.01 ± 5.22ï¼½ %, P <0.05), MDA level (ï¼»14.66 ± 2.75ï¼½ vs ï¼»10.14 ± 1.01ï¼½ nmol/ml, P <0.05), and TAC in the seminal plasma (ï¼»9.84 ± 0.90ï¼½ vs ï¼»11.14 ± 0.84ï¼½ U/ml, P <0.05). There were no statistically significant differences in the above post-medication parameters between the trial and control groups (P >0.05) except in TAC, which was markedly more improved in the former than in the latter (P <0.05), nor in the percentage of morphologically normal sperm before and after treatment in either of the two groups (P >0.05). After 3 months of treatment, 3 pregnancies were achieved in the trial group and 1 in the control (10.7% vs 3.45%, P >0.05). No obvious adverse events occurred during the treatment. CONCLUSIONS: Alpha-lipoic acid combined with tamoxifen citrate can evidently improve semen parameters in oligoasthenospermia patients by relieving oxidative stress injury.

Tumor size interpretation for predicting cervical lymph node metastasis using a differentiated thyroid cancer risk model.

Lymph node metastasis (LNM) is common in differentiated thyroid cancer (DTC), but management of clinically negative DTC is controversial. This study evaluated primary tumor size as a predictor of LNM. Multivariate logistic regression analysis was used for DTC patients who were treated with surgery between 2002 and 2012 in the Surveillance, Epidemiology, and End Results (SEER) database, to determine the association of tumor size at 10 mm increments with LNM. A predictive model was then developed to estimate the risk of LNM in DTC, using tumor size and other clinicopathological characteristics identified from the multivariate analysis. We identified 80,565 eligible patients with DTC in the SEER database. Final histology confirmed 9,896 (12.3%) cases affected with N1a disease and 8,194 (10.2%) cases with N1b disease. After the patients were classified into subgroups by tumor size, we found that the percentages of male sex, white race, follicular histology, gross extrathyroidal extension, lateral lymph node metastasis, and distant metastasis gradually increased with size. In multivariate analysis, tumor size was a significant independent prognostic factor for LNM; in particular, the odds ratio for lateral lymph node metastasis continued to increase by size relative to a 1-10 mm baseline. The coefficient for tumor size in the LNM predictive model was0.20, indicating extra change in log(odds ratio) for LNM as 0.2 per unit increment in size relative to baseline. In conclusion, larger tumors are likely to have aggressive features and metastasize to a cervical compartment. Multistratification by size could provide more precise estimates of the likelihood of LNM before surgery.

Predictive factors for recurrence of differentiated thyroid cancer in patients under 21 years of age and a meta-analysis of the current literature.

The influence of predictors for recurrence in relation to recurrence-free survival was analyzed retrospectively in differentiated thyroid cancer (DTC) patients under 21 years of age who underwent primary surgical treatment and who had a pathological diagnosis of DTC between 1983 and 2012 at Fudan University Cancer Hospital. Recurrences were retrospectively analyzed using a Cox regression model for the hazard ratio (HR) according to the clinicopathological features. A meta-analysis was performed with respect to the potential predictors for recurrence from current related studies. In the present study, there were 146 young patients aged from 7 to 20 years, with a female/male ratio of 2.65/1. Female gender was the only factor significantly associated with recurrence according to univariate (HR = 2.812, P = 0.037) and multivariate (HR = 4.107, P = 0.024) Cox regression analyses. Meta-analyses revealed that multifocality (HR = 1.91, P < 0.05) and presentation at diagnosis (HR = 1.39, P < 0.05) were highly associated with recurrence in young DTC patients. However, female gender and other factors, such as age (≤10 vs. 11-20 years), PTC (PTC vs. FTC), extrathyroidal extension, lymph node metastasis, total thyroidectomy (total vs. less than total), radioiodine therapy, and radiation history, were not associated with recurrence in young DTC patients. In conclusion, multifocality and presentation at diagnosis are strong predictive factors of recurrence in relation to recurrence-free survival. We recommend studies with larger sample sizes and longer follow-up to verify the influence of predictors for disease recurrence in young patients.

Factors influencing physicians' knowledge sharing on web medical forums.

Web medical forums are relatively unique as knowledge-sharing platforms because physicians participate exclusively as knowledge contributors and not as knowledge recipients. Using the perspective of social exchange theory and considering both extrinsic and intrinsic motivations, this study aims to elicit the factors that significantly influence the willingness of physicians to share professional knowledge on web medical forums and develops a research model to explore the motivations that underlie physicians' knowledge-sharing attitudes. This model hypothesizes that constructs, including shared vision, reputation, altruism, and self-efficacy, positively influence these attitudes and, by extension, positively impact knowledge-sharing intention. A conventional sampling method and the direct recruitment of physicians at their outpatient clinic gathered valid data from a total of 164 physicians for analysis in the model. The empirical results support the validity of the proposed model and identified shared vision as the most significant factor of influence on knowledge-sharing attitudes, followed in descending order by knowledge-sharing self-efficacy, reputation, and altruism.

Analysis on health information extracted from an urban professional population in Beijing.

BACKGROUND: The assembled data from a population could provide information on health trends within the population. The aim of this research was to extract and know basic health information from an urban professional population in Beijing. METHODS: Data analysis was carried out in a population who underwent a routine medical check-up and aged > 20 years, including 30 058 individuals. General information, data from physical examinations and blood samples were collected in the same method. The health status was separated into three groups by the criteria generated in this study, i.e., people with common chronic diseases, people in a sub-clinic situation, and healthy people. The proportion of both common diseases suffered and health risk distribution of different age groups were also analyzed. RESULTS: The proportion of people with common chronic diseases, in the sub-clinic group and in the healthy group was 28.6%, 67.8% and 3.6% respectively. There were significant differences in the health situation in different age groups. Hypertension was on the top of list of self-reported diseases. The proportion of chronic diseases increased significantly in people after 35 years of age. Meanwhile, the proportion of sub-clinic conditions was decreasing at the same rate. The complex risk factors to health in this population were metabolic disturbances (61.3%), risk for tumor (2.7%), abnormal results of morphological examination (8.2%) and abnormal results of lab tests of serum (27.8%). CONCLUSIONS: Health information could be extracted from a complex data set from the heath check-ups of the general population. The information should be applied to support prevention and control chronic diseases as well as for directing intervention for patients with risk factors for disease.

[L-carnitine: safe and effective for asthenozoospermia].

OBJECTIVE: One of the important reasons for male infertility is asthenozoospermia, for which there is no specific cure for the time being. The authors explored the clinical effect of L-carnitine for infertile males with asthenozoospermia. METHODS: A total of 135 patients with asthenozoospermia were randomly divided into Groups A (n = 68) and B (n = 67), the former treated with L-carnitine (2 g/d) and vitamin E, while the latter with vitamin E only, both for 3 months. All the patients received semen analyses before and after the treatment, and were observed for adverse effects. The pregnancy rates of their wives were recorded. RESULTS: Group A showed a significantly increased percentage of forward motile sperm after the treatment (45.4% +/- 11.1%) as compared with pretreatment (28.6% +/- 9.2%) (P < 0.01), but no statistically significant differences were found in sperm density and the percentage of the sperm of normal morphology (P > 0.05). The rate of pregnancy was significantly higher in Group A (31.1%) than in B (3.8%) after the treatment (P < 0.01). No adverse events were found during the treatment. CONCLUSION: L-carnitine, capable of significantly improving sperm motility and raising the rate of pregnancy, is a safe and effective therapeutic option for asthenozoospermia.

[Changes of sperm chromatin in oligo-astheno-teratozoospermia syndrome patients after treated by integrated Chinese and Western medicine].

OBJECTIVE: To observe the changes of sperm chromatin in patients with oligo-astheno-teratozoospermia (OAT) syndrome after treated by integrated Chinese and Western medicine. METHODS: Sixty patients with OAT syndrome were treated by integrated Chinese and Western medicine for 3 months. Their sperm samples were collected before and after the treatment, subjected to acridine orange staining and analyzed by fluorescent microscopy, flow cytometry and sperm routine detection. RESULTS: Significant differences were shown in the master-group sperm signals (P < 0.01) and at and COMPalphat (P < 0.05) by flow cytometry, as well as in the green and the red groups (P < 0.05) by fluorescent microscopy before and after the treatment. Changes in sperm concentration, motility, vitality and deformity were noted after the treatment, with statistic difference between pre- and post-treatment (P < 0.05) except in forward sperm concentration. CONCLUSION: Treatment by integrated Chinese and Western medicine can improve sperm chromatin in patients with OAT syndrome. Flow cytometry, along with fluorescent microscopy and sperm routine detection, plays an important role in the evaluation of male infertility therapy.

Emission from charge recombination during the pulse radiolysis of arylethynylpyrenes.

Emission from several 1-(arylethynyl)pyrenes with a substituent on the aryl group (REPy, R = phenyl (PEPy), 4-dimethylaminophenyl (NPEPy), 4-isopropoxyphenyl (OPEPy), 2-quinonyl (QEPy), and 9-(10-cyanoanthracenyl) (AEPy)) was studied with time-resolved fluorescence measurements during pulse radiolysis in benzene. NPEPy and AEPy showed only monomer emission, while PEPy, OPEPy, and QEPy showed both monomer and excimer emissions during pulse radiolysis. In addition, REPy's also showed long-lived emissions with very weak intensities in the absence of oxygen, which were assigned to the "P-type" delayed fluorescence derived from the triplet-triplet annihilation. The formation of REPy's in the singlet excited state (1REPy*) can be interpreted as the charge recombination between the REPy radical cation and anion (REPy*+ and REPy*-, respectively), which are initially generated from the radiolytic reaction in benzene. Both the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of PEPy are localized on the 1-pyrenyl (Py) moiety, while the HOMO of REPy's with an electron donating or withdrawing substituent on the benzene ring (R(D)EPy such as NPEPy and OPEPy or R(A)EPy such as QEPy and AEPy) is mainly localized on the donor moieties (R(D) or Py) and the LUMO on the acceptor ones (Py or R(A), respectively). Therefore, it is suggested that the one-electron oxidation and reduction of REPy's can occur from the donor and acceptor moieties, respectively. This scheme reasonably explains the relationship between the annihilation enthalpy changes (-Delta H' degrees) for the charge recombination of REPy*+ and REPy*- and the singlet excitation energies (E'(S1) of the REPy's. The results are compared with those in electrogenerated chemiluminescence.

Efficient emission from charge recombination during the pulse radiolysis of electrochemical luminescent donor-acceptor molecules with an ethynyl linkage.

Efficient monomer and excimer emission from various donor-acceptor substituted phenylethynes (PE), which are known as efficient electrogenerated chemiluminescent molecules, was observed with time-resolved fluorescence measurement during the pulse radiolysis in benzene. On the basis of the transient absorption and emission measurements, and steady-state measurements, the formation of PE in the singlet excited state (1PE*) and the excimer (1PE2*) can be interpreted by the charge recombination between the PE radical cation (PE.+) and the PE radical anion (PE.-) which are generated initially from the radiolytic reaction in benzene. It is suggested that the positive and negative charges are localized on the donor and acceptor moieties in the radical cation and anion, respectively. This mechanism is reasonably explained by the relationship between the annihilation enthalpy changes (-DeltaH' degrees ) and singlet excitation energies of donor-substituted phenyl(9-acridinyl)ethynes (1(a-e)). In addition to the monomer emission, the compounds bearing weak donors (1(a-d)) show the excimer emission due to a very small twist angle between the donor and acceptor moieties. For the phenyl(9-cyano-10-anthracenyl)ethynes (2(c) and 2(f)), although they also show the monomer and excimer emissions, it cannot be explained by the relationship between -DeltaH' degrees values and their singlet excitation energies, suggesting the formation of the ICT state and H-type excimer in which two 9-cyano-10-anthracenyl moieties are stacked face-to-face with donor bearing a benzene ring projecting perpendicularly away from each other through the charge recombination between 2.+) and 2.-) and/or triplet-triplet annihilation.

Synthesis, electronic properties, and electrochemiluminescence of donor-substituted phenylethynylanthronitriles.

A new series of pi-conjugated donor-acceptor compounds (1-6) with inherent redox centers have been prepared and studied with respect to their electronic properties. The photophysical characteristics of these compounds have been studied in relation to their structures. Cyclic voltammetry and UV-vis spectroelectrochemistry were used to probe the ground-state electronic properties of the neutral and charged species. The observed electronic absorption properties of the neutral and charged molecules are explained with the help of frontier orbital structures and electrostatic potential maps obtained from density functional theory (DFT, B3LYP/6-31G) calculations. Electrochemiluminescence (ECL) of this series of donor-substituted phenylethynylanthronitriles with different donors was also studied. The structure-property relationship of all of the compounds is discussed.

Donor-substituted phenyl-pi-chromones: electrochemiluminescence and intriguing electronic properties.

Phenylethynylchromones bearing different donor groups at the phenyl moiety have been prepared and their photophysical and electrogenerated chemiluminescence (ECL) properties have been studied with respect to their structural features. Intriguingly, the presence and variation of donor groups do not much influence the absorption spectra, which can be compared with the spectrum of unsubstituted chromone, whereas the photoluminescence (PL) spectra show pronounced changes. Density functional theory (DFT) calculations indicate enhancement of HOMO energy levels upon increasing the donor strength. The photophysical properties have also been studied in various solvents, and the PL spectra in particular show the anticipated trend. The introduction of pi-extension imparts ECL to the new molecules and the electronic coupling between the donor and the acceptor moieties through C-C triple bond influences ECL emission maxima. Weaker donors impart excimer ECL while stronger donors impart monomeric intramolecular charge transfer (ICT) ECL.

Highly fluorescent N,N-dimethylaminophenylethynylarenes: synthesis, photophysical properties, and electrochemiluminescence.

A new family of aryl-pi-donor-aryl molecules has been synthesized and studied with respect to their photophysical properties and electrogenerated chemiluminscence (ECL) for the first time. Anthracene, phenanthrene, naphthalene, biphenyl, and fluorene were coupled with N,N-dimethylanilino moiety via a C-C triple bond (1-7). Introduction of such a strong electron-donating moiety as N,N-dimethylanilino group through a triple bond imparts new properties to the resultant molecules that are not commonly observed for the parent arenes. All molecules show absorption in the near-visible region and emission totally in the visible region with high fluorescence quantum yields. Bright solid-state photoluminescence has also been noticed for all the compounds in the visible region. 9-Anthryl- and 1-naphthyl- derivatives exhibited blue-shifted electrochemiluminescence (ECL) relative to their photoluminescence because of aggregation. 9-Phenanthryl- and 2-naphthyl- derivatives did not show ECL. 2-Biphenyl derivative showed monomeric ECL while 4-biphenyl counterpart exhibited excimer ECL. No ECL was observed for 2-fluorenyl derivative. The observed electronic properties are discussed with regard to the structure of the molecules. The characteristics of the molecules chosen in the present study open up new prospects and promises for novel tunable organic materials, on the basis of simple extension of conjugation to promote intramolecular communication, for ECL, OLED, and other optoelectronic applications.

Efficient emission from charge recombination during the pulse radiolysis of electrochemical luminescent substituted quinolines with donor-acceptor character.

Efficient emission from various donor-acceptor quinolines with an ethynyl linkage (PnQ), which are known as efficient electrogenerated chemiluminescent molecules, was observed with time-resolved fluorescence measurement during the pulse radiolysis in benzene. On the basis of the transient absorption and emission measurements, and steady-state measurements, the formation of PnQ in the singlet excited state can be interpreted by charge recombination between the PnQ radical cation and the PnQ radical anion which are generated initially from the radiolytic reaction in benzene. The strong electronic coupling between the donor and acceptor through conjugation is responsible for the efficient emission during the pulse radiolysis of PnQ in benzene. It is suggested that the positive and negative charges are localized on the donor and acceptor moieties in the radical cation and anion, respectively. This mechanism is reasonably explained by the relationship between the annihilation enthalpy changes and singlet excitation energies of PnQ. The formation of the intramolecular charge transfer state is assumed for PnQ in the singlet excited state with a strong electron donating substituent. The emission from PnQ is suggested to originate from PnQ in the singlet excited state formed from the charge recombination between the PnQ radical cation and the PnQ radical anion during the pulse radiolysis. This is strong evidence for the efficient electrogenerated chemiluminescence of PnQ.

Electronic polarization reversal and excited state intramolecular charge transfer in donor/acceptor ethynylpyrenes.

An attempt to tune the electronic properties of pyrene (Py) by coupling it with a strong electron donor (-PhNMe2, DMA)/acceptor (anthronitrile, AN) through an ethynyl bridge has been undertaken. A moderate electron donor (iPrOPh-, IPP)/acceptor (2-quinolinyl, 2Q) has also been incorporated, and all four molecules were studied with reference to a neutral molecule, namely, 1-phenylethynylpyrene (PhEPy). All the arylethynylpyrenes (ArEPy's) have been thoroughly characterized, and their electronic properties were studied by absorption and emission spectral properties of these ArEPy's. The electrochemical characteristics were also studied for arriving at the electrochemical band gap which has been compared with the HOMO-LUMO energy gap derived from the photophysical measurements and theoretical calculations performed by density functional theory (DFT) using B3LYP/6-31G basis sets. The results obtained from experimental and theoretical studies are critically discussed.