Photochemical synthesis and device application of acene-phenacene hybrid molecules, dibenzo[n]phenacenes (n = 5-7)

Dibenzo[n]phenecenes (DBnPs, n = 5-7) were conveniently synthesised through Mallory photocyclization as the key step. Effective mobilities of single-crystal field-effect transistors of DBnPs were evaluated to demonstrate that C2h-symmetrical DB6P shows higher performance than C2v-symmetrical DB5P and DB7P.

Terahertz-field-induced polar charge order in electronic-type dielectrics

Ultrafast electronic-phase change in solids by light, called photoinduced phase transition, is a central issue in the field of non-equilibrium quantum physics, which has been developed very recently. In most of those phenomena, charge or spin orders in an original phase are melted by photocarrier generations, while an ordered state is usually difficult to be created from a non-ordered state by a photoexcitation. Here, we demonstrate that a strong terahertz electric-field pulse changes a Mott insulator of an organic molecular compound in κ-(ET)₂Cu[N(CN)₂]Cl (ET = bis(ethylenedithio)tetrathiafulvalene), to a macroscopically polarized charge-order state; herein, electronic ferroelectricity is induced by the collective intermolecular charge transfers in each dimer. In contrast, in an isostructural compound, κ-(ET)₂Cu₂(CN)₃, which shows the spin-liquid state at low temperatures, a similar polar charge order is not stabilized by the same terahertz pulse. From the comparative studies of terahertz-field-induced second-harmonic-generation and reflectivity changes in the two compounds, we suggest the possibility that a coupling of charge and spin degrees of freedom would play important roles in the stabilization of polar charge order.

Fabrication of ring oscillators using organic molecules of phenacene and perylenedicarboximide

Organic field-effect transistors (FETs) can be applied to radio-frequency identification tags (RFIDs) and active-matrix flat-panel displays. For RFID application, a cardinal functional block is a ring oscillator using an odd number of inverters to convert DC voltage to AC. Herein, we report the properties of two ring oscillators, one formed with [6]phenacene for a p-channel FET and N,N′-dioctyl-3,4,9,10-perylenedicarboximide (PTCDI-C8) for an n-channel FET, and one formed with 3,10-ditetradecylpicene ((C₁₄H₂₉)₂-picene) for a p-channel FET and PTCDI-C8 for an n-channel FET. The former ring oscillator provided a maximum oscillation frequency, f_osc of 26 Hz, and the latter a maximum f_osc of 21 Hz. The drain–drain voltage, V_DD, applied to these ring oscillators was 100 V. This may be the first step towards a future practical ring oscillator using phenacene molecules. The values of field-effect mobility, μ in the p-channel [6]phenacene FET and n-channel PTCDI-C8 FET, which form the building blocks in the ring oscillator with an f_osc value of 26 Hz, are 1.19 and 1.50 × 10⁻¹ cm² V⁻¹ s⁻¹, respectively, while the values in the p-channel (C₁₄H₂₉)₂-picene FET and n-channel PTCDI-C8 FET, which form the ring oscillator with an f_osc of 21 Hz, are 1.85 and 1.54 × 10⁻¹ cm² V⁻¹ s⁻¹, respectively. The μ values in the p-channel FETs are higher by one order of magnitude than those of the n-channel FET, which must be addressed to increase the value of f_osc. Finally, we fabricated a ring oscillator with ZrO₂ instead of parylene for the gate dielectric, which provided the low-voltage operation of the ring oscillator, in which [6]phenacene and PTCDI-C8 thin-film FETs were employed. The value of f_osc obtained in the ring oscillator was 24 Hz. In this ring oscillator, the V_DD value applied was limited to 20 V. The durability of the ring oscillators was also investigated, and the bias stress effect on the f_osc and the amplitude of the output voltage, V_out are discussed. This successful operation of ring oscillators represents an important step towards the realization of future practical integrated logic gate circuits using phenacene molecules.

A ring oscillator consisting of p-channel and n-channel organic FETs.

A case of pubic abscess after prostate cancer surgery and radiotherapy treated with rectus femoris muscle flap

We report the case of a 95-year-old man with soft tissue deficiency associated with a pubic abscess that occurred 30 years after prostate cancer surgery and radiation therapy. A fistula with purulent discharge without any obvious cause appeared in the midline of the lower abdomen and progressed to a soft tissue defect in which several calcium phosphate stones of 5-8 mm in diameter were found. Computed tomography showed calcium deposits on the surface of the pubis and irregular zonal calcifications extending from the pubis to the medial region of both thighs. Conservative treatment did not improve the patient's condition; thus, surgical treatment was performed. The pedicled rectus femoris muscle flap was elevated from the left thigh and transferred to fill the tissue defect, then a split thickness skin graft was applied on it. The tissue defect was successfully repaired, and the patient was able to regain ambulation ability. In the present case, it was presumed that urine exudation around the bladder due to radiation cystitis was involved in the formation of ectopic calculi and subsequent infection. In reconstructing a complex defect associated with infection, using muscle flaps to fill the dead space with well vascularized tissue is considered to be appropriate. In our case, we chose a rectus femoris muscle flap, which has advantages in volume and versatility of transposition owing to long vascular pedicle and requires no microsurgical vascular anastomosis. As a result, the preoperative activity was maintained, the infection was treated, and a good course was obtained.

Efficacy of combination-chemotherapy with pirarubicin, ifosfamide, and etoposide for soft tissue sarcoma: a single-institution retrospective analysis

Background

The standard chemotherapy regimens for soft tissue sarcoma are doxorubicin-based. This retrospective study aimed to assess the efficacy and safety of pirarubicin, ifosfamide, and etoposide combination therapy for patients with this disease.

Methods

Between 2008 and 2017, 25 patients with soft tissue sarcoma were treated with pirarubicin (30 mg/m², 2 days), ifosfamide (2 g/m², 5 days), and etoposide (100 mg/m², 3 days) every 3 weeks. The primary endpoint was overall response, and the secondary endpoint was adverse events of this regimen.

Results

Responses to this regimen according to RECIST criteria were partial response (n = 9, 36%), stable disease (n = 9, 36%) and progressive disease (n = 7, 28%). During the treatment phase, frequent grade 3 or worse adverse events were hematological toxicities including white blood cell decreases (96%), febrile neutropenia (68%), anemia (68%), and platelet count decreases (48%). No long-term adverse events were reported during the study period.

Conclusion

This regimen was comparable to previously published doxorubicin-based combination chemotherapy in terms of response rate. Although there were no long-lasting adverse events, based on our results, severe hematological toxicity should be considered.

Distribution of Solitary and Multiple Enchondromas of the Hand

BACKGROUND/AIM

Although some patients with enchondroma have multiple lesions, no study has investigated the distribution of lesions in patients with multiple enchondromas.

PATIENTS AND METHODS

This retrospective study included 118 patients with enchondroma of the hand. The incidence and characteristic feature of multiple enchondromas of the hand were investigated.

RESULTS

Four patients (3.4%) had multiple enchondromas. In all the patients with multiple enchondromas, the lesions occurred in the middle phalanx, proximal phalanx, and metacarpal bone in the same digital ray.

CONCLUSION

The development of the hand rapidly progresses from intrauterine day 33 to day 54. The digital rays are evident on intrauterine day 41, and separation of the distal phalanx, middle phalanx, proximal phalanx, and metacarpal bone is completed until intrauterine day 54. The successive occurrence of multiple enchondroma lesions in the same digital ray in all four cases suggests that the occurrence of lesions preceded the separation of the hand bones and the lesions were divided during the development of these bones.

Facile synthesis of picenes incorporating imide moieties at both edges of the molecule and their application to n-channel field-effect transistors

Picene derivatives incorporating imide moieties along the long-axis direction of the picene core (C_n-PicDIs) were conveniently synthesized through a four-step synthesis. Photochemical cyclization of dinaphthylethenes was used as the key step for constructing the picene skeleton. Field-effect transistor (FET) devices of C_n-PicDIs were fabricated by using ZrO₂ as a gate substrate and their FET characteristics were investigated. The FET devices showed normally-off n-channel operation; the averaged electron mobility (μ) was evaluated to be 2(1) × 10⁻⁴, 1.0(6) × 10⁻¹ and 1.4(3) × 10⁻² cm² V⁻¹ s⁻¹ for C₄-PicDI, C₈-PicDI and C₁₂-PicDI, respectively. The maximum μ value as high as 2.0 × 10⁻¹ cm² V⁻¹ s⁻¹ was observed for C₈-PicDI. The electronic spectra of C_n-PicDIs in solution showed the same profiles irrespective of the alkyl chain lengths. In contrast, in thin films, the UV absorption and photoelectron yield spectroscopy (PYS) indicated that the lowest unoccupied molecular orbital (LUMO) level of C_n-PicDIs gradually lowered upon the elongation of the alkyl chains, suggesting that the alkyl chains modify intermolecular interactions between the C_n-PicDI molecules in thin films. The present results provide a new strategy for constructing a high performance n-channel organic semiconductor material by utilizing the electronic features of phenacenes.

Picenediimide derivatives serve as the active layer of n-channel thin-film field-effect transistors displaying a maximum charge carrier mobility as high as 2.0 × 10⁻¹ cm² V⁻¹ s⁻¹.

Pyogenic tenosynovitis of the wrist due to Corynebacterium striatum in a patient with dermatomyositis: A case report

INTRODUCTION

Corynebacterium striatum is common contaminant in clinical specimens. Here, we report a rare case of pyogenic tenosynovitis of the wrist caused by C striatum in a dermatomyositis patient taking oral immunosuppressants.

PATIENT CONCERNS

A 67-year-old Japanese woman with dermatomyositis had a history of multiple intraarticular injections of corticosteroids to the right wrist joint for the treatment of osteoarthritis. She was admitted to our hospital with a painful lump on the right dorsal wrist lasting for three months. MRI revealed cellulitis of the dorsum of the right wrist and hand and fluid collection in the extensor tendon sheath. C striatum was detected in the cultures of three samples of synovial fluid taken from the dorsal hand.

DIAGNOSIS

Pyogenic tenosynovitis of the wrist due to C striatum.

INTERVENTIONS

The infection was successfully controlled with synovectomy and adjuvant antibiotic therapy.

OUTCOMES

There has been no sign of recurrence for 12-months after the surgical treatment.

LESSONS

This is the first reported case of pyogenic tenosynovitis due to C striatum in a patient with dermatomyositis. Clinicians should be aware that patients undergoing immunosuppressive therapy have a risk of C striatum infection.

Successful treatment with hydroxychloroquine for systemic lupus erythematosus with cutaneous involvement accompanied by a xanthomatous reaction

Antimalarials are usually recommended for the first-line systemic treatment of cutaneous lupus erythematosus. Alopecia in patients with discoid lupus erythematosus (DLE) is sometimes a refractory condition in spite of topical therapies. We herein described a case of DLE on the scalp with a pathological change of a xanthomatous reaction, which was successfully treated with hydroxychloroquine (HCQ). A 34-year-old woman presented with hair loss to the parietal region. She had been diagnosed with systemic lupus erythematosus (SLE) four years previously. Treatment with 30 mg/day of prednisolone (PSL) had been initiated, and the dose was gradually reduced. At 10 mg/day of PSL, she had noticed her hair loss. Physical examination revealed some small erythematous lesions to the parietal region with accompanying hair loss. Pathological findings of the erythematous lesion on her head revealed thickening of the basement membrane zone, the interface dermatitis with vacuolar degeneration, and both superficial perivascular and perifollicular infiltration of inflammatory cells in the dermis. In addition, there was an infiltrate of xanthomatous cells detected in the papillary dermis, which were positive for CD68 and CD163. The patient started treatment with HCQ at a dose of 200 mg/day. The skin lesions completely resolved within five months after initiation of HCQ without increase in the dose of PSL. Xanthomatous reactions are rarely recognized in lupus erythematosus. The chronic epithelial injury in DLE could be implicated in triggering the secondary reactive process of a xanthomatous reaction. We believe that the reaction seen in our patient was a secondary change to pathological alteration due to SLE. However, as yet unrecognized factors may play a role in the development of a xanthomatous reaction in DLE.

Blue fluorescence from N,O-coordinated BF2 complexes having aromatic chromophores in solution and the solid state

We prepared amide-heterocycle (HC) compounds having various aromatic π-electron systems (Ar), such as phenyl, naphthyl, furyl, thienyl and phenanthryl moieties, and converted them as ligands to difluoroboronated complexes, Ar@HCs. Blue fluorescence from Ar@HCs was observed in solution and the solid state, and the fluorescence quantum yields (Φ_f) and lifetimes (τ_f) were determined. The Φ_f values in CHCl₃ were as small as 0.1 except for the phenanthrene derivatives (0.4-0.6). Observation of the triplet-triplet absorption upon laser flash photolysis of Ar@HCs in solution indicated that the fluorescence process competes with intersystem crossing to the triplet state. Blue fluorescence in the solid state was observed with the Φ_f values of 0.3-0.7. Based on the crystallographic data, the relationship between the crystal structures and emission features of Ar@HCs in the solid state is discussed.

Topological charge transport by mobile dielectric-ferroelectric domain walls

The concept of topology has been widely applied in condensed matter physics, leading to the identification of peculiar electronic states on three-dimensional (3D) surfaces or 2D lines separating topologically distinctive regions. In the systems explored so far, the topological boundaries are built-in walls; thus, their motional degrees of freedom, which potentially bring about new paradigms, have been experimentally inaccessible. Here, working with a quasi-1D organic material with a charge-transfer instability, we show that mobile neutral-ionic (dielectric-ferroelectric) domain boundaries with topological charges carry strongly 1D-confined and anomalously large electrical conduction with an energy gap much smaller than the one-particle excitation gap. This consequence is further supported by nuclear magnetic resonance detection of spin solitons, which are required for steady current of topological charges. The present observation of topological charge transport may open a new channel for broad charge transport-related phenomena such as thermoelectric effects.

P5612In vivo histological and clinical evaluation of layered culprit plaque by optical coherence tomography in stable angina patients

Background

In patients with stable angina pectoris (SAP), exact mechanism of plaque progression overtime is still unclear due to lack of histological evaluation. Directional coronary atherectomy (DCA) allows for the differential cutting of atherosclerotic lesions and for the histological examination.

Purpose

The aims of this study were to compare the histological features obtained by DCA and layered pattern (LP) by OCT, and to establish the prevalence and clinical characteristics of LP in culprit lesion form SAP patients.

Methods

SAP patients who underwent OCT imaging guide PCI in our medical school hospital between June 2016 and June 2018 were included into this study. This was two-fold histological and clinical studies. In a histological study, we evaluated histological features of 42 specimens from 18 patients who underwent DCA and compare OCT findings. Lesions were classified into the following categories based on the OCT finding before DCA cutting; homogeneous or heterogeneous group. Furthermore, lesions in heterogeneous group were classified into 2 categories; LP or non-LP group. In a clinical study, 205 target lesions form 205 patients were categorized as shown above at minimum lumen area (MLA) sites. Plaque characteristics were compared among these groups.

Results

In the histological study, 9 (21.4%) specimens were classified in homogeneous group and 33 (78.6%) in heterogeneous group. In 33 heterogeneous group, LP group were observed in 12 specimens (36.3%). Of 12 LP group, 10 LP group consisted of intramural thrombosis. In clinical study, 39 (19.0%) lesion were classified in homogeneous group and 166 (81.0%) in heterogeneous group. In 166 heterogeneous group, LP group were observed in 75 lesions (45.2%). Of heterogeneous group, LP group had significantly smaller MLA (1.5±0.9 mm2 vs 1.9±1.0 mm2, p<0.05) and higher rate of microchannels (57.3% vs 15.4%, p<0.05) than non-LP group.

A representative layered pattern case

Conclusions

LP in culprit lesion with SAP was significantly associated with intramural thrombosis. MLA sites in LP was significantly smaller than in non-LP group. These data suggest that thrombus formation and subsequent their organization overtime might contribute to the plaque progression even in SAP patients.

Doublon-holon pairing mechanism via exchange interaction in two-dimensional cuprate Mott insulators

Coupling of charge and spin degrees of freedom is a critical feature of correlated electron oxides, as represented by the spin-related mechanism of a Cooper pair under high-T _c superconductivity. A doublon-holon pair generated on an antiferromagnetic spin background is also predicted to attract each other via the spin-spin interaction J, similar to a Cooper pair, while its evidence is difficult to obtain experimentally. Here, we investigate such an excitonic effect by electroreflectance spectroscopy using terahertz electric field pulses in undoped cuprates: Nd₂CuO₄, Sr₂CuO₂Cl₂, and La₂CuO₄. Analyses of the spectral changes of reflectivity under electric fields reveal that the splitting of odd-parity and even-parity excitons, a measure of doublon-holon binding energy, increases with J. This trend is reproduced by t-J-type model calculations, providing strong evidence of the spin-related doublon-holon pairing. Agreement with the calculations supports the s-wave symmetry of the doublon-holon pair in contrast to the d-wave Cooper pair in doped cuprates.