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Abstract: Novel organosilicon polymers having donor–acceptor type π-conjugated units in the backbone were prepared by Stille-coupling reactions of bis(tributylstannylthienyl)silanes with diiodoquinoxialine, benzothiadiazole, and benzothiaselenazole. Dehaloganative copolymerization of di(bromothienyl)silanes and dibromoquinoxaline was also studied, which gave the corresponding random copolymer. Applications of these polymers to dye-sensitized solar cells (DSSCs) were examined and it was found that the polymer containing benzoselenadiazole units as the acceptor exhibited the best performance as the sensitizer among the present polymers. [Copyright &y& Elsevier]

Abstract: After TiO2 nanoparticles were surface modified, conductive polyaniline (PANI) layer was chemically grafted on the surface of the self-assembled monolayer (SAM) coated TiO2 nanoparticles, resulting in PANI/SAM-TiO2 composites. In the preparation process of the hybrid composites, γ-aminopropyltriethoxysilane was used as a coupling agent to form a dense aminopropylsilane monolayer with active sites for the graft polymerization of aniline. The resulted composite nanoparticles were characterized by using TEM, FTIR, TGA, and UV–vis-diffuse reflectance spectroscopy. The thermogravimetric analysis confirmed that the inserted SAM layer improved the thermal stability of the PANI–TiO2 nanocomposites. Compared with neat-TiO2 nanoparticles without any surface modification, moreover, the PANI/SAM-TiO2 nanocomposites showed better photocatalytic activity in photodegradation of methyl orange under sunlight, which was partly attributed to the sensitizing effect of PANI. [Copyright &y& Elsevier]

Abstract: The photoeffects of trapped electrons (Ti3+) in partially reduced TiO2 nanoparticles were studied by in situ ESR spectroscopy. For the pure phase samples, upon illumination with an energy lower than the band gap, the Ti3+ spectra decreased in intensity; however, the initial ESR signal was restored within 30min in the dark at 77K. For the TiO2 (P-25) particles, the ESR line shape changed significantly with being constant in the integrated intensity of the signal after the restoration. It was found that the trapped electrons can transfer from the anatase phase to the rutile phase in TiO2 (P-25) by photoexcitation. [Copyright &y& Elsevier]

Abstract: UV irradiation of poly(organosilanylene-2,5-diethynylenesiloles) in benzene with an excess of Fe(CO)5 led to the formation of Fe(CO)3-coordinated silole units in the polymer backbone. The Fe(CO)3-coordinated polymers exhibited suppressed π-conjugation, relative to the parent non-coordinated polymers. Hole-transporting properties of poly(organosilanylene-2,5-diethynylenesiloles) were examined by the performance of EL devices containing the polymer layer as the hole-transport and Alq3 layer as the electron-transporting emitter. [Copyright &y& Elsevier]

Diethylsilanylene- and tetramethyldisilanylene-1,6-diethynylpyrene alternating polymers (1 and 2) were prepared by the reactions of 1,6-di(lithioethynyl)pyrene and the respective dichloroorganosilanes. The hole-transporting properties of the resulting polymers were evaluated by the performance of electroluminescent (EL) devices with the structure of indium–tin–oxide/polymer/Alq/Mg–Ag, in comparison with those of an organosilanylene-9,10-diethynylanthracene alternating polymer (3), reported previously. Among them, the device with polymer 1 exhibited the best performance with a maximum luminescence of 6000 cd m−2, which increased to 16 000 cd m−2 when electron-blocking TPD layer was introduced between the polymer and Alq layers. Polymers 1–3 were found to be photoactive and irradiation of the polymer films with a UV lamp led to a drastic drop of the luminance of the device, being applicable to the patterning of EL images. [Copyright &y& Elsevier]

Polymers composed of an alternating arrangement of organosilanylene and pentathienylene units, [SiBu2-X-SiBu2-(2,5-C4H2S)5]n (1: X=none, 2: X=O) were prepared and their application to the hole-transport in double-layer electroluminescent (EL) devices was studied. The EL devices with the structure of ITO/1 or 2/Alq/Mg:Ag emitted a green light resulting from Alq emission by applying the bias voltage. The device with 1 showed a lower turn-on voltage than that with 2, while almost the same maximum luminance of 4000 cd m−2 was obtained from both of the devices. [Copyright &y& Elsevier]

Abstract: In the cyclic voltammogram measured using a polyaniline (PANI) coated electrode in the presence of chloranil (CHR), the anodic peak potential of PANI was directly proportional to log[CHR]. A new absorption shoulder was evident at around 450nm in the UV–visible absorption spectrum of PANI after the electro-oxidation. These facts implied that PANI incorporated CHR. The measurements of the ESR spectra and the magnetic susceptibility (χ g) of the PANI incorporating CHR revealed that the incorporation magnetized PANI. Although no ferromagnetic property was observed for the PANI, it had an unusual paramagnetic property because χ g was not inversely proportional to temperature. [Copyright &y& Elsevier]

While organic thermoelectric materials are more affordable, flexible, and accessible than their inorganic counterparts, some of these conducting polymers are brittle, impeding their practical application. For addressing this problem, free-standing poly(3,4-ethylenedioxythiophene) (PEDOT) films were synthesized by the galvanostatic polymerization of 3,4-ethylenedioxythiophene in a polymer electrolyte, which consisted of sulfonated polyhydroxy ether with fluorine groups (S-PHEF) dissolved in propylene carbonate. The thermoelectric properties of these films, such as electrical conductivity, Seebeck coefficient, and power factor, were investigated in relation to the polymerization conditions. These included current density, polymerization temperature, and the molecular weight of S-PHEF. The results indicated that the thermoelectric properties of the synthesized films improved by approximately three times when compared with those of the PEDOT films doped by sulfonated polyhydroxy ether without fluorine groups (S-PHE), which were prepared under the same polymerization conditions. Further, it was observed that with an increase in the molecular weight of the dopant polyanion, the quality of the film improved and the charge mobility was enhanced. Image 1 • Free-standing conducting polymer films were synthesized using fluorine-containing polyanion. • The introduction of fluorine group improved the thermoelectric properties. • Film morphology was affected by the condition of the electrolytic polymerization. [ABSTRACT FROM AUTHOR]

Nitroxyl radicals, characterized by unique redox properties, have been investigated for their potential influence on the photovoltaic conversion properties of dye-sensitized solar cells (DSSCs). In this study, we investigated the influence of nitroxyl radicals as donor sites in DSSCs. We observed that the redox activity of nitroxyl radicals significantly enhanced the photovoltaic conversion efficiency of DSSCs; this finding can offer new insights into the application of these radicals in solar energy conversion. Furthermore, we found that increasing the proportion of nitroxyl radicals improved the DSSC performance. Through a combination of experimental and analytical approaches, we elucidated the mechanism underlying this enhancement and highlighted the potential for more efficient DSSCs using nitroxyl radicals as key components. These findings provide new avenues for developing advanced DSSCs with improved performances and sustainability.

Rationale: Venovenous extracorporeal membrane oxygenation (ECMO) is recommended for the treatment of critically ill patients with acute respiratory distress syndrome due to coronavirus disease 2019 (COVID-19). However, ECMO management can cause both bleeding and thrombotic complications. There are insufficient coagulofibrinolytic data for appropriate ECMO management in patients with COVID-19., Patient Concerns: A 48-year-old man with severe COVID-19-acute respiratory distress syndrome underwent long-term venovenous ECMO management for 48 days. Refractory oronasal bleeding developed on day 13, so the administration of unfractionated heparin was ceased for 29 days., Diagnosis: The patient showed dynamic coagulofibrinolytic responses associated with ECMO management, as shown by fibrin/fibrinogen degradation products, soluble fibrin, thrombin-antithrombin complex, and plasmin-α2-plasmin inhibitor complex elevations, suggesting the development of ECMO-induced coagulopathy., Interventions: We assessed coagulofibrinolytic markers to decide the appropriate timing for controlling excessive activation of coagulation by exchanging ECMO circuits. Moreover, viscoelastic hemostatic assays were used for adequate transfusion of blood products., Outcomes: Safe long-term ECMO management was completed, which was withdrawn on day 48. The patient was weaned off mechanical ventilation on day 57 and was transferred to another hospital for rehabilitation., Lessons: Monitoring the coagulofibrinolytic status using markers and viscoelastic hemostatic assays may be effective for safe long-term ECMO management even without anticoagulant therapy., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Tracheostomy is an important procedure for the treatment of severe coronavirus disease-2019 (COVID-19). Older age and obesity have been reported to be associated with the risk of severe COVID-19 and prolonged intubation, and anticoagulants are often administered in patients with severe COVID-19; these factors are also related to a higher risk of tracheostomy. Cricotracheostomy, a modified procedure for opening the airway through intentional partial cricoid cartilage resection, was recently reported to be useful in cases with low-lying larynx, obesity, stiff neck, and bleeding tendency. Here, we investigated the usefulness and safety of cricotracheostomy for severe COVID-19 patients., Materials and Methods: Fifteen patients with severe COVID-19 who underwent cricotracheostomy between January 2021 and April 2022 with a follow-up period of ≥ 14 days were included in this study. Forty patients with respiratory failure not related to COVID-19 who underwent traditional tracheostomy between January 2015 and April 2022 comprised the control group. Data were collected from medical records and comprised age, sex, body mass index, interval from intubation to tracheostomy, use of anticoagulants, complications of tracheostomy, and decannulation., Results: Age, sex, and days from intubation to tracheostomy were not significantly different between the COVID-19/cricotracheostomy and control/traditional tracheostomy groups. Body mass index was significantly higher in the COVID-19 group than that in the control group ( P  = 0.02). The rate of use of anticoagulants was significantly higher in the COVID-19 group compared with the control group ( P  < 0.01). Peri-operative bleeding, subcutaneous emphysema, and stomal infection rates were not different between the groups, while stomal granulation was significantly less in the COVID-19 group ( P  = 0.04)., Conclusions: These results suggest that cricotracheostomy is a safe procedure in patients with severe COVID-19., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Mukai, Okada, Konishi, Okita, Ogawa, Nishikawa, Annen, Ohshita, Matsumoto, Murata, Harima, Kikucih, Aibara, Sei, Aoishi, Asayama, Sato, Takagi, Tanaka-Nishikubo, Teraoka, Hato, Takeba and Sato.)

Background: We experienced a case of early stage lung cancer involving a morbidly obese patient. Obesity is associated with a higher incidence of surgical complications. We examined the effectiveness of laparoscopic sleeve gastrectomy as a primary weight loss procedure in a morbidly obese patient who required oncological surgery., Case Presentation: A 64-year-old morbidly obese female with a body mass index of 43.5 kg/m 2 was referred to our hospital to undergo weight loss. A right-sided lung mass was found incidentally on computed tomography conducted in preparation for laparoscopic sleeve gastrectomy, which was performed prior to tumor surgery. As a result, weight loss was achieved within 2.5 months after the laparoscopic sleeve gastrectomy, and the patient's type-2 diabetes, hypertension, and dyslipidemia, which are linked to obesity, were markedly ameliorated. After a quick intraoperative pathological inspection revealed that the tumor was malignant, thoracoscopic right lung superior lobe resection was performed safely., Conclusions: Laparoscopic sleeve gastrectomy proved to be a powerful approach in a case in which a morbidly obese patient with early stage cancer needed to lose weight rapidly.

Thermoelectric properties of regioregular poly(3-hexylthiophene) (P3HT) were investigated in correlation with doping level measured by a potential-step chronocoulometry (PSC) method. It was found that the log-log plot of Seebeck coefficients against doping levels showed a good linearity, whose slope value was around -1.

D-π-A dyes NI-4 bearing a pyridyl group, YNI-1 bearing two pyridyl groups and YNI-2 bearing two thienylpyridyl groups as the anchoring group on the TiO 2 surface have been developed as dye sensitizers for dye-sensitized solar cells (DSSCs), where NI-4 and YNI-2 can adsorb onto the TiO 2 electrode through the formation of the coordinate bond between the pyridyl group of the dye and the Lewis acid site (exposed Ti n+ cations) on the TiO 2 surface, but YNI-1 is predominantly adsorbed on the TiO 2 electrode through the formation of the hydrogen bond between the pyridyl group of the dye and the Brønsted acid sites (surface-bound hydroxyl groups, Ti-OH) on the TiO 2 surface. The difference in the dye-adsorption mode among the three dyes on the TiO 2 surface has been investigated from the adsorption equilibrium constant (K ad ) based on the Langmuir adsorption isotherms. It was found that the K ad values of YNI-1 and YNI-2 are higher than that of NI-4, and more interestingly, the K ad value of YNI-2 is higher than that of YNI-1. This work demonstrates that that for the D-π-A dye sensitizers with the pyridyl group as the anchoring group to the TiO 2 surface the number of pyridyl groups and the dye-adsorption mode on the TiO 2 electrode as well as the molecular structure of the dye sensitizer affect the K ad value for the adsorption of the dye to the TiO 2 electrode, that is, resulting in a difference in the K ad value among the D-π-A dye sensitizers NI-4, YNI-1 and YNI-2.

Pentacene films vacuum-sublimed on a cross-linked polymeric insulator (CPVP-C 6 ) prepared using poly(4-vinylphenol) (PVP) and 1,6-bis(trichlorosilyl)hexane (C 6 ) were studied with a special concern on possible influences of the CPVP-C 6 thickness on the electrical characteristics of the pentacene films. It was found that the conductivities of the pentacene films on a thin CPVP-C 6 film (10 nm) were approximately 2 orders of magnitude higher than those on a glass substrate and increased slightly with the increase in the thickness of the underlying CPVP-C 6 film. In addition, the X-ray diffraction measurements showed that the stacking structure of pentacene molecules was remarkably enhanced by increasing the thickness of the CPVP-C 6 film, suggesting that the increase in conductivity is due, at least in part, to the improvement in carrier mobilities caused by the growth of large pentacene grains. An attempt to directly evaluate carrier mobilities using pentacene/CPVP-C 6 field-effect transistors was made, and a seeming increase in the carrier mobilities observed with the increase in the CPVP-C 6 thickness was ascribed to a hygroscopic nature of the CPVP-C 6 film, which was evidenced by the capacitance and quartz crystal microbalance measurements. Possible reasons are discussed to explain the enhanced conductivities of the pentacene films on the increased thicknesses of CPVP-C 6 ., Competing Interests: The authors declare no competing financial interest.

A new-type of donor-acceptor π-conjugated (D-π-A) fluorescent dyes NI3-NI8 with a pyridine ring as electron-withdrawing-injecting anchoring group have been developed and their photovoltaic performances in dye-sensitized solar cells (DSSCs) are investigated. The short-circuit photocurrent densities and solar energy-to-electricity conversion yields of DSSCs based on NI3-NI8 are greater than those for the conventional D-π-A dye sensitizers NI1 and NI2 with a carboxyl group as the electron-withdrawing anchoring group. The IR spectra of NI3-NI8 adsorbed on TiO(2) indicate the formation of coordinate bonds between the pyridine ring of dyes NI3-NI8 and the Lewis acid sites (exposed Ti(n+) cations) of the TiO(2) surface. This work demonstrates that the pyridine rings of D-π-A dye sensitizers that form a coordinate bond with the Lewis acid site of a TiO(2) surface are promising candidates as not only electron-withdrawing anchoring group but also electron-injecting group, rather than the carboxyl groups of the conventional D-π-A dye sensitizers that form an ester linkage with the Brønsted acid sites of the TiO(2) surface., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

A new class of fluorescence sensor for detection of water in organic solvents based on photo-induced electron transfer (PET) of anthracene coupled with an amino acid has been designed and developed.

Heteropolycyclic donor--acceptor (D--A) structural isomers of benzofuro[2,3-c]oxazolo[4,5-a]carbazole-type (2a-f) and benzofuro[2,3-c]oxazolo[5,4-a]carbazole-type fluorescent dyes (3a-f), which differ in the position of oxygen and nitrogen atoms of the oxazole ring, have been synthesized, and their photophysical and electrochemical properties have been investigated. The fluorescent dyes 2a-f exhibit much stronger intramolecular charge transfer (ICT) absorption and fluorescence bands than 3a-f. Both of the D-pi-A structural isomers showed bathochromic shifts of the fluorescence band and a decrease in the fluorescence quantum yields with increasing solvent polarity (i.e., positive fluorescence solvatochromism), and the bathochromic shifts for 3a-f were larger than those for 2a-f. The fluorescent dyes 2a-c and 3a-c, which have cyano and carboxyl groups, and carboxylic acid ester as electron-withdrawing substituents, exhibited significant fluorescence solvatochromic properties, compared to 2e, 2f, 3e and 3f without an electron-withdrawing substituent. The fluorescence solvatochromism of the fluorescent dyes were analyzed with the Lippert-Mataga correlation. Moreover, to elucidate the differences of photophysical properties among the fluorescent dyes, we have performed time-resolved fluorescence spectroscopic measurements, and a change of the electronic or molecular structures between the ground and excited states was evaluated by a comparison of the experimental radiative rate constant (k(r)) with the Strickler-Berg rate constant (kSB(r)). The electrochemical properties of 2a-f and 3a-f were determined by cyclic voltammetry, which demonstrated that these fluorescent dyes have similar HOMO energy levels, but different LUMO energy levels. Semi-empirical molecular orbital calculations (AM1 and INDO/S) have been carried out to elucidate the effects of the substituents and chromophore skeleton on photophysical properties of the two D-pi-A structural isomers. These studies indicated that the ICT characteristics in the excited state are different among the fluorescent dyes, which is a principal reason for the differences of the fluorescence solvatochromism and the substituent dependent fluorescence properties among the two D-pi-A structural isomers.

The role of the phenazine structure in the stabilization of charged states in polyaniline was studied by in situ electron spin resonance (ESR)-UV/vis-near-infrared (NIR) spectroelectrochemistry of polyaniline and the copolymers of aniline and a phenazine derivative (3,7-diamino-5-phenylphenazinium chloride, phenosafranine). It is shown that the copolymer can be prepared by electropolymerization, and its structure was confirmed by mass spectrometry and IR spectroscopy. The electrochemistry of polyaniline and its copolymer pointed to preferred stabilization of a polaron pair in the charged states at the initial charge transfer reaction instead of polarons that are formed by equilibrium reaction at higher electrode potentials. A second polaron pair is detected for higher doped states of the polymer films. A mechanism of the formation of charged states in polyaniline and their equilibrium is given. It is shown that in situ ESR-UV/vis-NIR spectroelectrochemistry is the method of choice to differentiate between polarons and polaron pairs in their potential-dependent formation. Thus, by this in situ spectroelectrochemical method the influence of phenazine structure on the formation of polarons in aniline polymers and copolymers can be followed.

A simple and renewable four-band platinum electrode for in situ conductivity measurement of polymers is described. A model is developed to evaluate contact resistance between the electrode and polyaniline film and calibrate the film resistances obtained by two-probe and four-probe methods. The conductivity of the film is calculated from the calibrated resistance. By comparing the effects of band thickness, gap width, and film thickness, it is found that the ratio K of the middle gap width to the thickness of the internal two platinum bands is the most important parameter to characterize one four-band electrode. An ideal four-band electrode should have large K and wide middle gap as possible so long as the film can uniformly cover the electrode. Under this case, the influence of contact resistance on the four-probe measurement of film resistance is negligible. It is shown that contact resistance depends on the oxidation state of the film. It rises nonlinearly with increasing film resistance.

Donor-acceptor pi-conjugated benzofuro[2,3-c]oxazolo[4,5-a]carbazole-type fluorescent dyes 3a, 3b, 8a, and 8b with a carboxyl group at different positions of the chromophore skeleton have been designed and synthesized. The absorption and fluorescence spectra and cyclic voltammograms of the fluorescent dyes agree very well, showing that the position of the carboxyl group has a negligible influence on the photophysical and electrochemical properties of these dyes. When these dyes are used in dye-sensitized solar cells, however, their photovolatic performances are considerably different. The short-circuit photocurrents and energy conversion efficiencies under a simulated solar light increase in the order: 3a (2.12 mA cm(-2), 1.00%) approximately 3b (2.10 mA cm(-2), 1.06%) > 8b (1.50 mA cm(-2), 0.67%) > 8a (0.84 mA cm(-2), 0.34%). Based on semi-empirical molecular orbital calculations (AM1 and INDO/S) together with spectral analyses and their photovolatic performance, the relationships between the observed photovolatic properties and the chemical structures of the benzofuro[2,3-c]oxazolo[4,5-a]carbazole-type fluorescent dyes are discussed. It is found that strong interaction between a TiO(2) surface and the electron accepting moiety of the dye leads to a high photovoltaic performance.

An unusual electrochemical response is found for oligoalkylthiophene (13T) films in acetonitrile. A pristine 13T film exhibits a stable redox wave in cyclic voltammogram when the anodic potential limit is below 0.6 V, whereas the redox peaks shift clearly to the negative side by ca. 0.1 V once the 13T film experiences a potential beyond 0.7 V. After this electrochemical stimulus is imposed on a pristine 13T film, the absorption and emission spectra change their features. These findings, along with the measurements with varying thicknesses of 13T films, suggest that a pristine 13T film is a mixture of two phases to be oxidized at separate potentials and that one phase can be switched to the other by the potential stimulation. A plausible model proposed for explaining these observations assumes that a key parameter characteristic of the two phases is a conformation of 13T molecules in the solid state and a change in conformation, leading to the shift of the redox potentials and the change of optical properties, is induced by electrochemical generation of bipolarons on the half units of the oligomers in the pristine 13T film.

Mobilities of charge carriers in cast and spun films of poly(3-hexylthiophene)s (PHTs) with regioregularities of 97%, 81%, 70%, and 54% (denoted as PHT97%, PHT81%, PHT70%, and PHT54%, respectively) are evaluated as a function of doping level. A common feature of mobility vs doping level plots for all the PHT films is that the mobility decreases initially with the increase of the doping level and then starts to rise drastically at ca. 1% doping level. No large mobility difference is observed between cast and spun films of each PHT. In contrast, the difference in regioregularity of PHT resulted in a large mobility difference, especially in the low doping regime. At the highest doping levels of ca. 20%, the apparent mobility values reach 0.4 and 0.01 cm(2) V(-1) s(-1) for the cast films of PHT97% and PHT54%, respectively. These features of the mobility plots are discussed in connection with self-assembled structures of PHT films studied by electrochemical, in-situ ESR, in-situ UV-vis-NIR, and X-ray diffraction measurements. It is concluded first that mobilities of polarons are mainly controlled by the rate of an interchain charge hopping and second that the evolution of metallic conduction featured by the sharp mobility increase is irrelevant to the interchain stacking, or rather governed by an intrachain route.