Degradation phenomena of quantum dot light-emitting diodes induced by high electric field.

Quantum dots possess exceptional optoelectronic properties, such as narrow bandwidth, controllable wavelength, and compatibility with solution-based processing. However, for efficient and stable operation in electroluminescence mode, several issues require resolution. Particularly, as device dimensions decrease, a higher electric field may be applied through next-generation quantum dot light-emitting diode (QLED) devices, which could further degrade the device. In this study, we conduct a systematic analysis of the degradation phenomena of a QLED device induced by a high electric field, using scanning probe microscopy (SPM) and transmission electron microscopy (TEM). We apply a local high electric field to the surface of a QLED device using an atomic force microscopy (AFM) tip, and we investigate changes in morphology and work function in the Kelvin probe force microscopy mode. After the SPM experiments, we perform TEM measurements on the same degraded sample area affected by the electric field of the AFM tip. The results indicate that a QLED device could be mechanically degraded by a high electric field, and work function changes significantly in degraded areas. In addition, the TEM measurements reveal that In ions migrate from the indium tin oxide (ITO) bottom electrode to the top of the QLED device. The ITO bottom electrode also deforms significantly, which could induce work function variation. The systematic approach adopted in this study can provide a suitable methodology for investigating the degradation phenomena of various optoelectronic devices.

Flexible narrowband organic photodiode with high selectivity in color detection.

This study describes the design of a flexible narrowband organic photodiode (OPDs) with a novel structure. A bulk heterojunction of poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C70-butyric acid methyl ester (PC70BM) is introduced as a photoactive layer, with an optimized thickness of 160 nm, and a MoO3/Ag/MoO3 (MAM) multilayer electrode and polyimide (PI) film substrate were used. The OPD with the device architecture of PI/MAM/P3HT:PC70BM/Al showed narrowband photodiode performance in the 500-650 nm wavelength range. The maximum external quantum efficiency (EQE) of the OPD was 15.41% at 570 nm, which dropped to ∼0% outside the operation wavelength range. This narrowband detectivity originated from the cutoff of light at wavelengths below 500 nm by the PI substrate and photoreactivity of P3HT:PC70BM at wavelengths between 300 and 650 nm. Outer bending tests performed over 1000 cycles revealed that the average maximum EQE remained at ∼15%. The maximum responsivity of the OPD was calculated to be 0.07 A W-1 at 570 nm. The OPD device showed a narrow response spectrum with a full width at half maximum of 100 nm. This research suggests a new approach for the fabrication of flexible OPDs with high selectivity in color detection.

Sorafenib versus cytotoxic chemotherapy for patients with advanced hepatocellular carcinoma: a retrospective, single-institution study.

BACKGROUND: Prior to the 2008 advent of sorafenib, traditional cytotoxic agents were the therapeutic mainstay for patients with advanced hepatocellular carcinoma (HCC). We thus undertook a clinical study of sorafinib and conventional cytotoxic therapy for HCC, comparing efficacy and safety. METHODS: From January, 2002 to December, 2009, 173 patients with unresectable HCC were reviewed retrospectively. Among them, 44 (25.4%) had been treated with sorafenib, and the remainder had received cytotoxic therapy (CTX). We evaluated objective response rate (ORR), progression free survival (PFS), overall survival (OS), and toxicity profiles. RESULTS: Median OS of sorafinib was 23.0 weeks (95% CI, 8.1-37.9) vs 43.6 weeks (95% CI, 34.0-53.2) for CTX. Likewise, median PFS was 11.1 weeks (95% CI, 6.5-15.8) vs 12.4 weeks (95% CI, 8.1-16.7) for sorafenib and CTX, respectively. Neither parameter differed significantly (OS, p = 0.105; PFS, p = 0.496). ORR and disease control rate for sorafenib were 2.3% and 52.3% vs 6.2% and 43.4% for CTX. CTX-treated patients experienced more Grade 3/4 neutropenia (19.7% vs 0% for sorafenib), while sorafenib therapy was more often linked to dermatologic toxicities (all grades), such as hand-foot skin reaction, rash, and pruritus. CONCLUSION: Although sorafenib has become the treatment of choice for advanced HCC, there are still unsettled issues regarding the optimal use of sorafenib. Our analysis indicates that conventional CTX can be another option of treatment for advanced HCC. To improve clinical outcomes, further prospective investigations which define the role of CTX are needed.

Can metformin change the prognosis of pancreatic cancer? Retrospective study for pancreatic cancer patients with pre-existing diabetes mellitus type 2.

BACKGROUNDS: The effect of metformin on survival in patients with pancreatic cancer is controversial. AIMS: To investigate the beneficial effect of metformin in pancreatic cancer patients. METHODS: We retrospectively analyzed patients with pancreatic cancer and pre-existing diabetes mellitus type 2 who were treated at Severance Hospital (Seoul, South Korea) between May 2005 and December 2013. RESULTS: Among 237 enrolled patients, 117 patients (49.4%) were exposed to metformin. The median overall survival was 13.7 months for the metformin group versus 8.9 months for the non-metformin group (P=0.001) In univariate analysis, metformin exposure, low serum carbohydrate antigen 19-9 levels (<1000 U/mL), small tumor size (≤20 mm), no tail involvement, good performance status (ECOG 0 vs. 1 or 2), and resectable cancer stage were associated with favorable survival outcomes (all P<0.05). In multivariate analysis, in addition to low serum carbohydrate antigen 19-9 levels (<1000 U/mL) and resectable cancer stage, metformin exposure was significantly associated with longer survival with a hazard ratio of 0.61 (P=0.001). Additionally, the cumulative duration of metformin use was significantly correlated with a favorable survival outcome. CONCLUSION: Our findings supported that metformin exposure was associated with survival benefits in patients with pancreatic cancer and pre-existing type 2 diabetes mellitus, especially among those with an advanced cancer stage.

Enhancement of Emission Lifetime of CNT Emitters by Coating ZnO on the CNT Surface.

Carbon nanotubes (CNTs) have been investigated as field-emission sources owing to their high electrical conductivity and high aspect ratio. However, practical applications demand that the emission lifetime of CNTs be further improved. Since ZnO demonstrates impressive electrical and thermal conductivity, when coated on the surface of CNTs, it can allow the CNT field emitters to endure high electrical stress and high temperature. Moreover, ZnO nanostructures protect the CNT emitters from being bombarded by high-energy ions, which are accelerated by the high electric field. From the result of emission lifetime measurements at the emission current density of 100 mA/cm2, we found that the emission lifetime was increased by more than a factor of 2 when ZnO had been coated onto the CNT emitters. The observation registers as an important contribution to the practical application of CNT emitters with long-term emission stability, as well as with high emission currents. In this work, we elucidate the detailed mechanism of long-term stability that can be achieved by coating ZnO nanostructures on the surface of CNTs.

Efficacy and safety of everolimus in Korean patients with metastatic renal cell carcinoma.

PURPOSE: Few studies have investigated the effects of everolimus therapy in Asian populations. This study evaluates the safety and efficacy of everolimus in Korean patients with metastatic renal cell carcinoma (mRCC). METHODS: We retrospectively reviewed records of Korean patients with mRCC (n = 22) who received everolimus between January 2009 and July 2010 and evaluated them for efficacy and safety. RESULTS: One patient achieved a partial response, and 16 patients had stable disease, corresponding to an overall response rate of 4.5 % and a disease control rate of 77.3 %. Median progression-free survival was 5.4 months (95 % CI 0.9-9.8). Median overall survival was not reached. Univariate analysis showed that Memorial Sloan-Kettering Cancer Center risk (P = .004), thrombocytopenia (P = .018), hyperglycemia (P = .007) and hypertriglyceridemia (P = .041) were associated with disease progression. The most common adverse events (AEs) were hypertriglyceridemia and anemia, similar to Western patients. Creatinine and aspartate aminotransferase levels were higher than those reported for Western patients. The most common grade ≥3 AEs in this study were hypertriglyceridemia and anemia, compared with lymphopenia (14 %) in Western patients. CONCLUSIONS: Safety of everolimus in Korean mRCC patients differed from that reported in Western patients. Therefore, liver function enzymes, hemoglobin levels, lipid profile and chest CT scans should be monitored more closely in Asian mRCC patients receiving everolimus.

Phase II study of cisplatin with irinotecan as induction chemotherapy followed by chemoradiotherapy for unresectable stage III non-small cell lung cancer.

BACKGROUND/AIM: We evaluated the anti-tumor activity and safety of cisplatin with irinotecan (IP) induction chemotherapy followed by chemoradiotherapy with etoposide/cisplatin (EP). PATIENTS AND METHODS: Induction chemotherapy consisted of irinotecan i.v. and cisplatin i.v. and was administered on day 1 and day 8 of each cycle. Patients underwent two cycles of chemotherapy with a 3-week interval. In the absence of progressive disease, 66 Gy radiation was administered concurrently with etoposide on days 1 to 5 and 29 to 33, as well as with cisplatin on day 1, 8, 29, and 36. RESULTS: Twenty patients were enrolled between July 2007 and December 2009. This study was closed prematurely due to lack of efficacy in induction chemotherapy. The overall response rate was 45% [95% confidence interval (CI), 25 to 65%], which did not meet the upper limit for first stage rejection of the treatment. The rates of 3-year progression-free survival and overall survival were 17.1% (95% CI, 0 to 36.8%) and 25% (95% CI, 0.2 to 49.8%), respectively. The primary toxicities included neutropenia, diarrhea and fatigue. CONCLUSION: This study failed to demonstrate a benefit for induction chemotherapy which was characterized by suboptimal antitumor activity and was poorly tolerated, with excess treatment-related toxicity.

Prevalence and associated factors of psychological distress among Korean cancer patients.

OBJECTIVES: This study primarily aimed to investigate the prevalence and associated factors of psychological distress among Korean cancer patients. Its secondary objective was to classify mental illnesses among cancer patients with significant psychological distress. METHODS: We administered the Modified Distress Thermometer (MDT), Hospital Anxiety and Depression Scale (HADS), and Center for Epidemiologic Studies-Depression Scale (CES-D) to consecutive, newly diagnosed cancer patients and conducted subsequent psychiatric interviews. A multiple logistic regression produced a discriminate profile of individuals with psychological distress. RESULTS: Among 295 participants, 85 (28.8%) were identified as patients with psychological distress. Female gender [odds ratio (OR)=1.97], low educational level (OR=2.25) and low performance status (OR=4.10) were significantly associated with this condition. Among the 38 patients with psychological distress who received psychiatric assessment, the most common mental illness was adjustment disorder (n=23, 69.7%). CONCLUSION: The results of this study showed that approximately one-third of the cancer patients suffered from psychological distress. We recommend that physicians focus on the psychological status of female cancer patients with low levels of education and poor performance status.

A case of combined hepatocellular-cholangiocarcinoma with favorable response to systemic chemotherapy.

Combined hepatocellular-cholangiocarcinoma (cHCC-CC) is a rare form of primary liver cancer composed of cells with histopathologic features of both hepatocellular carcinoma (HCC) and cholangiocarcinoma (CC). Because of its low incidence, the information on clinical outcomes of cHCC-CC is very limited and there are no published reports describing non-surgical treatment options for cHCC-CC. We report a case of cHCC-CC exhibiting a favorable response to systemic chemotherapy with doxorubicin and cisplatin. A 62-year-old man who recurred after a right lobectomy for cHCC-CC received sorafenib for palliative systemic therapy, but follow up imaging studies showed disease progression. He received 2nd line chemotherapy with doxorubicin at 60 mg/m(2) together with cisplatin at 70 mg/m(2). After 2 cycles of chemotherapy, a computed tomography scan of the chest showed markedly decreased size and number of the multiple lung metastases. After completing 8 cycles of 2nd line therapy, we changed the regimen to a fluorouracil (5-FU) mono therapy because of the toxicities associated with doxorubicin and cisplatin. To date, the patient has completed his 15th cycle of 5-FU mono therapy with the disease status remaining stable during 18 months of follow-up.

Wernicke's encephalopathy in advanced gastric cancer.

PURPOSE: With their prolonged survival and malnutrition, cancer patients, and especially gastrointestinal (GI) tract cancer patients, can develop Wernicke's encephalopathy (WE). The aim of this study is to remind physicians of the importance of WE and prompt management in patients with GI tract cancer. MATERIALS AND METHODS: This study is a retrospective review of 2 cases of WE in advanced gastric cancer (AGC) patients, and we review the literature for cases of GI tract cancer related to WE. RESULTS: A 48-year-old female with AGC presented dizziness and diplopia for 5 days and a 20 kg weight loss. Neurologic exam showed nystagmus and gaze disturbance. Her symptoms improved after daily parenteral injection of thiamine 100 mg for 17 days. A 58-year-old female with AGC presented with sudden disorientation, confusion and 15 kg weight loss. Neurologic exam showed gaze limitation and mild ataxia. Despite daily parenteral injection of thiamine 100 mg for 4 days, she died 5 days after the onset of neurologic symptoms. Combining the cases noted in the literature review with our 2 cases, the 7 gastric cancer cases and 2 colorectal cancer cases related to WE showed similar clinical characteristics; 1) a history of long-period malnutrition and weight loss, 2) relatively typical neurologic signs and symptoms and 3) specific magnetic resonance image findings. Except for 2 patients who had irreversible neurologic symptoms, the other 7 patients were improved with prompt thiamine treatment. CONCLUSION: It is important to consider WE in GI tract cancer patients with acute neurologic symptoms and who are in a state of malnutrition. Thiamine should be given as soon as possible when WE is suspected.

Novel sunitinib strategy in metastatic renal cell carcinoma on hemodialysis: intermittent dose of sunitinib after hemodialysis.

The proper dose and schedule of sunitinib have yet to be established for patients with metastatic renal cell carcinoma (RCC) on hemodialysis. We reviewed two patients with metastatic RCC on hemodialysis who had been treated with sunitinib in Yonsei Cancer Center, Yonsei University College of Medicine. Fifty milligrams of sunitinib was administered intermittently after each hemodialysis session (3 or 4 times a week). Overall responses were partial response in both cases. Progression-free survivals were 16 and 6 months, respectively, at the time of reporting (April 2010). Both subjects tolerated the treatment.

Clinicopathologic features of metachronous or synchronous gastric cancer patients with three or more primary sites.

PURPOSE: We investigated the clinicopathologic information of patients with gastric cancer with multiple primary cancers (GC-MPC) of three or more sites. MATERIALS AND METHODS: Between 1995 and 2009, 105,908 patients were diagnosed with malignancy at Severance Hospital, Yonsei University Health System. Of these, 113 (0.1%) patients with MPC of three or more sites were registered, and 41 (36.3%) of these were GC-MPC. We retrospectively reviewed the clinical data and overall survival using the medical records of these 41 GC-MPC patients. We defined synchronous cancers as those occurring within 6 months of the first primary cancer, while metachronous cancers were defined as those occurring more than 6 months later. RESULTS: Patients with metachronous GC-MPC were more likely to be female (p=0.003) and young than patients with synchronous GC-MPC (p=0.013). The most common cancer sites for metachronous GC-MPC patients were the colorectum, thyroid, lung, kidney and breast, while those for synchronous GC-MPC were the head and neck, esophagus, lung, and kidney. Metachronous GC-MPC demonstrated significantly better overall survival than synchronous GC-MPC, with median overall survival durations of 4.7 and 14.8 years, respectively, and 10-year overall survival rates of 48.2% and 80.7%, respectively (p<0.001). CONCLUSION: Multiplicity of primary malignancies itself does not seem to indicate a poor prognosis. The early detection of additional primary malignancies will enable proper management with curative intent.