Control of the dual emission from a thermally activated delayed fluorescence emitter containing phenothiazine units in organic light-emitting diodes

The development of single-component organic dual light-emitting molecules is of interest for a range of applications including white organic light-emitting diodes. Herein, a new thermally-activated delayed fluorescent molecule containing 4,6-bis-phenyl phenothiazine as donor units and 2-thiophene-1,3,5-triazine as acceptor unit was synthesized using a simple cost-effective method. This compound shows two stable molecular conformations due to the presence of the phenothiazine units in its molecular structure. These conformers exhibit different photophysical properties in both solution and thin films. The electroluminescence properties of this novel emitter were then examined in organic light-emitting diodes and the results provide useful insights into the influence of the device architecture on the dual emission characteristics. The experimental results were consistent with the optical simulations and the optimized architecture led to the fabrication of electroluminescent devices with an external quantum efficiency of 11.5% and a maximum luminance value of 10 370 cd m⁻².

A novel TADF emitter showing dual emission is synthesized and applied to OLEDs with an external quantum efficiency of 11.5%.     

HHV-8 positive Kaposi sarcoma in a patient with end-stage renal disease undergoing hemodialysis: no regressive effect of captopril

Human herpesvirus 8 (HHV-8) has been associated with Kaposi sarcoma (KS) in renal transplant recipients. On the other hand, there are only a few reported cases of KS in patients with end stage renal failure receiving hemodialysis. Here, we report a case of HHV-8 positive, disseminated KS, in a 70-year-old man with renal failure, receiving hemodialysis for 7 months. The KS lesions had begun to develop almost at the same time with the onset of dialysis. The patient had been on captopril therapy since the diagnosis of renal failure. Captopril has been reported to inhibit angiogenesis, and by this way, to reduce tumor growth. However, in our patient, the lesions had developed under the treatment of captopril, and showed no evidence of regression after withdrawal of the drug.     

Hypopigmented large-cell acanthoma of the eyelid

Large-cell acanthoma is an asymptomatic, slightly keratotic, usually hyperpigmented epidermal lesion that is mostly seen in the sun-exposed skin of middle-aged or elderly people. It is characterized by extraordinarily large keratinocytes that can reach up to twice their normal size without a change in the nucleus/cytoplasm ratio. Here, we describe a chronic case of large-cell acanthoma that involved the whole upper eyelid of a 67-year-old man for at least 15 years. The lesion was almost depigmented and demonstrated altered consistency of the eyelid, causing lax and folded skin. The lesion responded to treatment with topical tretinoin and urea. This case verifies the benign character of large-cell acanthoma and demonstrates how it may have atypical presentations.     

Conjunctival squamous cell carcinoma in a patient with hemodialysis-related porphyria cutanea tarda

Hemodialysis-related porphyria cutanea tarda (HRPCT) is characterized by porphyria-like blisters on sun-exposed parts of the face, arms and hands due to elevated porphyrin levels. Conjunctival squamous cell carcinoma (CSCC) is a rare cancer that typically occurs on the sun-damaged ocular surface of elderly male patients. Herein, we report a case of CSCC in a 72-year-old patient who had been on hemodialysis for 8 years, and had been followed up with a diagnosis of HRPCT for 3 years. To our knowledge, this is the first case report documenting an association between HRPCT and CSCC, which may reflect a pathogenetic process connecting them.