Combinatorial screening of halide perovskite thin films and solar cells by mask-defined IR laser molecular beam epitaxy.

As an extension of combinatorial molecular layer epitaxy via ablation of perovskite oxides by a pulsed excimer laser, we have developed a laser molecular beam epitaxy (MBE) system for parallel integration of nano-scaled thin films of organic-inorganic hybrid materials. A pulsed infrared (IR) semiconductor laser was adopted for thermal evaporation of organic halide (A-site: CH3NH3I) and inorganic halide (B-site: PbI2) powder targets to deposit repeated A/B bilayer films where the thickness of each layer was controlled on molecular layer scale by programming the evaporation IR laser pulse number, length, or power. The layer thickness was monitored with an in situ quartz crystal microbalance and calibrated against ex situ stylus profilometer measurements. A computer-controlled movable mask system enabled the deposition of combinatorial thin film libraries, where each library contains a vertically homogeneous film with spatially programmable A- and B-layer thicknesses. On the composition gradient film, a hole transport Spiro-OMeTAD layer was spin-coated and dried followed by the vacuum evaporation of Ag electrodes to form the solar cell. The preliminary cell performance was evaluated by measuring I-V characteristics at seven different positions on the 12.5 mm × 12.5 mm combinatorial library sample with seven 2 mm × 4 mm slits under a solar simulator irradiation. The combinatorial solar cell library clearly demonstrated that the energy conversion efficiency sharply changes from nearly zero to 10.2% as a function of the illumination area in the library. The exploration of deposition parameters for obtaining optimum performance could thus be greatly accelerated. Since the thickness ratio of PbI2 and CH3NH3I can be freely chosen along the shadow mask movement, these experiments show the potential of this system for high-throughput screening of optimum chemical composition in the binary film library and application to halide perovskite solar cell.

[Nonfunctioning pancreatic neuroendocrine tumor with extensive calcification].

A 54-year-old woman exhibited pancreatic calcification on abdominal ultrasonography. Diagnostic imaging revealed a 20-mm mass with a 12-mm calcification in the tail of the pancreas. The mass was weakly enhanced in the early phase of contrast-enhanced CT. We performed pancreatectomy and splenectomy. Histopathological diagnosis was a nonfunctioning pancreatic neuroendocrine tumor (PNET), grade 2. This is a rare case of PNET with extensive calcification.

MUC2 expression and prevalence of high-grade dysplasia and invasive carcinoma in mixed-type intraductal papillary mucinous neoplasm of the pancreas.

BACKGROUND/OBJECTIVES: Morphological types and mucin protein expressions classify intraductal papillary mucinous neoplasms (IPMNs). Main duct (MD)-IPMN mostly consists of intestinal type (I-type), which expresses MUC2. Branch duct (BD)-IPMN mostly consists of gastric type (G-type), which does not express MUC2. However, the definition of mixed-type IPMN has yet to be clarified and it contains various histological types. The aim of this study was to investigate the relationship between MUC2 expression and the presence of high-grade dysplasia (HGD) and invasive carcinoma, especially in mixed-type IPMN. METHODS: This retrospective study included 101 consecutive patients with surgically resected IPMNs between April 2001 and October 2012. All patients were morphologically classified into four distinct types (I-type, G-type, PB-type: pancreatobilliary, O-type: oncocytic) and immunohistochemical reactivity of various anti-mucin antibodies were investigated. RESULTS: According to the classification of the 2012 international guidelines, the numbers (and histomorphological types: I/G/PB/O) of MD, mixed-type, and BD-IPMNs were 16 (12/4/0/0), 45 (16/28/1/0), and 40 (0/38/1/1). Prevalence of MUC2 expression in MD, mixed-type, and BD-IPMNs were 75% (12/16), 36% (16/45), and 0% (0/40). In mixed-type IPMN, the prevalence of HGD and/or invasive carcinoma in MUC2-positive IPMN was significantly higher than that of MUC2-negative IPMN (HGD + invasive carcinoma: 88% vs. 38%, p = 0.0017; invasive carcinoma: 50% vs. 21%, p = 0.042). Multivariate analysis showed that MUC2 expression is an independent predictive factor of HGD and invasive carcinoma in mixed IPMN (odds ratio 14.6, 95% CI 2.5-87.4, p = 0.003). CONCLUSIONS: In mixed-type IPMN, MUC2 expression clearly identified HGD and invasive carcinoma and may provide most appropriate surgical indication.

Lifestyle factors associated with gastroesophageal reflux disease in the Japanese population.

BACKGROUND: We aimed to clarify the lifestyle factors associated with erosive esophagitis and non-erosive reflux disease (NERD) in a Japanese population. METHODS: Among 886 subjects who underwent health screening, we selected, according to their scores on the FSSG (frequency scale for symptoms of gastroesophageal reflux disease; GERD) questionnaire and the findings of upper gastrointestinal endoscopy, 138 subjects with erosive esophagitis (EE), 148 subjects with NERD (absence of esophagitis, FSSG score ≥8, and acid reflux-related symptoms score ≥4), and 565 control subjects (absence of esophagitis and FSSG score ≤7). We compared clinical characteristics and various lifestyle factors in these three groups. RESULTS: The lifestyle factors significantly associated with NERD compared with findings in the control group were intake of egg (odds ratio [OR] 1.89, 95% confidence interval [CI] 1.01-3.50), sleep shortage (OR 2.44, 95% CI 1.54-3.88), and strong psychological stress (OR 1.77, 95% CI 1.18-2.62). In male subjects, current smoking (OR 2.06, 95% CI 1.13-3.74; OR 1.87, 95% CI 1.09-3.20) was a significant risk factor for both NERD and EE. Moreover, alcohol >200 kcal/day (OR 3.99, 95% CI 1.03-15.55) and intake of a large quantity of food at supper (OR 7.85, 95% CI 1.66-37.05) were significant risk factors for EE in subjects with hiatal hernia. Intake of a large quantity of food at supper (OR 2.09, 95% CI 1.06-4.13) was more common in the NERD group than in the EE group. CONCLUSIONS: There were differences in the associated lifestyle factors between patients with NERD and those with EE, and there was also a gender-related difference between these groups.

A case of lymphoepithelial cyst of pancreas with unique "cheerios-like" appearance in EUS.

Lymphoepithelial cyst (LEC) of the pancreas is a rare benign lesion, which is difficult to diagnose preoperatively. We describe a case of a 60-year-old male, incidentally diagnosed as having LEC of the pancreas, which was managed by laparoscopic distal pancreatectomy. Most of the reported cases of LEC were asymptomatic and diagnosed incidentally. A high index of suspicion under EUS may help in making a diagnosis and avoiding unnecessary surgery in asymptomatic patients. In particular, the unique "cheerios-like" appearance of the lesion in EUS, which was also found in this case, might be helpful in the differential diagnosis of pancreatic cystic lesions.

A case of lipomatous pseudohypertrophy of the pancreas diagnosed by EUS-FNA.

We report the case of a 56-year-old female with lipomatous hypertrophy of the pancreas. Abdominal CT and MRI showed fatty replacement over the entire pancreas. The pancreatic parenchyma was completely absent. ERCP showed no abnormal findings in the main pancreatic duct. EUS-FNA was performed to achieve a definitive diagnosis. Histological features of the FNA specimens revealed that adipose tissue generally replaced the pancreatic parenchyma, and pancreatic acini were identified with a scattered distribution. To consider the differential diagnosis of lipomatous pseudohypertrophy of the pancreas, it is necessary to distinguish it from obesity, diabetes, and age-related pancreatic fat infiltration and liposarcoma. By performing EUS-FNA, it was possible to obtain a definitive diagnosis in this patient. In conclusion, EUS-FNA may be helpful to make a definitive diagnosis in patients with lipomatous hypertrophy of the pancreas.