Enhanced overall efficiency of GaInN-based light-emitting diodes with reduced efficiency droop by Al-composition-graded AlGaN/GaN superlattice electron blocking layer

AlxGa1-xN/GaN superlattice electron blocking layers (EBLs) with gradually decreasing Al composition toward the p-type GaN layer are introduced to GaInN-based high-power light-emitting diodes (LEDs). GaInN/GaN multiple quantum well LEDs with 5- and 9-period Al-composition-graded AlxGa1-xN/GaN EBL show comparable operating voltage, higher efficiency as well as less efficiency droop than LEDs having conventional bulk AlGaN EBL, which is attributed to the superlattice doping effect, enhanced hole injection into the active region, and reduced potential drop in the EBL by grading Al compositions. Simulation results reveal a reduction in electron leakage for the superlattice EBL, in agreement with experimental results. (C) 2013 AIP Publishing LLC.open1133sciescopu

Implant selection for successful reverse total shoulder arthroplasty

Reverse total shoulder arthroplasty (RTSA) emerged as a new concept of arthroplasty that does not restore normal anatomy but does restore function. It enables the function of the torn rotator cuff to be performed by the deltoid and shows encouraging clinical outcomes. Since its introduction, various modifications have been designed to improve the outcome of the RTSA. From the original cemented baseplate with peg or keel, a cementless baseplate was designed that could be fixed with central and peripheral screws. In addition, a modular-type glenoid component enabled easier revision options. For the humeral component, the initial design was an inlay type of long stem with cemented fixation. However, loss of bone stock from the cemented stem hindered revision surgery. Therefore, a cementless design was introduced with a firm metaphyseal fixation. Furthermore, to prevent complications such as scapular notching, the concept of lateralization emerged. Lateralization helped to maintain normal shoulder contour and better rotator cuff function for improved external/internal rotation power, but excessive lateralization yielded problems such as subacromial notching. Therefore, for patients with pseudoparalysis or with risk of subacromial notching, a medial eccentric tray option can be used for distalization and reduced lateralization of the center of rotation. In summary, it is important that surgeons understand the characteristics of each implant in the various options for RTSA. Furthermore, through preoperative evaluation of patients, surgeons can choose the implant option that will lead to the best outcomes after RTSA.Level of evidence: IV

Colonic Mucosal Necrosis Following Administration of Calcium Polystryrene Sulfonate (Kalimate) in a Uremic Patient

Colonic necrosis is known as a rare complication following the administration of Kayexalate (sodium polystryrene sulfonate) in sorbitol. We report a rare case of colonic mucosal necrosis following Kalimate (calcium polystryrene sulfonate), an analogue of Kayexalate without sorbitol in a 34-yr-old man. He had a history of hypertension and uremia. During the management of intracranial hemorrhage, hyperkalemia developed. Kalimate was administered orally and as an enema suspended in 20% dextrose water to treat hyperkalemia. Two days after administration of Kalimate enema, he had profuse hematochezia, and a sigmoidoscopy showed diffuse colonic mucosal necrosis in the rectum and sigmoid colon. Microscopic examination of random colonic biopsies by two consecutive sigmoidoscopies revealed angulated crystals with a characteristic crystalline mosaic pattern on the ulcerated mucosa, which were consistent with Kayexalate crystals. Hematochezia subsided with conservative treatment after a discontinuance of Kalimate administration

Dieulafoy's Lesion of Jejunum: Presenting Small Bowel Mass and Stricture

Dieulafoy's lesion is an uncommon cause of gastrointestinal bleeding. Hemorrhage occurs through mucosal erosion from an abnormally dilated submucosal artery. Although Dieulafoy's lesion is usually located in the stomach, it may occur anywhere in the gastrointestinal tract. We report here on a case of jejunal Dieulafoy's lesion presenting as a mass and short segment stricture on CT and enteroclysis

Predictors of Hospitalization Among Newly Admitted Skilled Nursing Facility Residents: Rethinking the Role of Functional Decline

Purpose: Hospital transfer from a skilled nursing facility (SNF) is costly, and many are potentially preventable. This study examines: 1) whether functional decline is a predictor of hospital transfer, and 2) the magnitude of relationships between predictors (functional impairment and chronic medical illness) and hospital transfer from SNFs. Methods: We used Minimum Data Set (MDS) Version 2.0 in the state of Michigan between 2007 and 2009. In total, 196,662 new SNF admissions were observed. Multilevel generalized estimating equations and regression models were performed for each functional and clinical domain while adjusting for demographic variables and change in activities of daily living (ADL). Results: 65% of recently admitted SNF residents experienced functional decline after SNF admission, and 58% were readmitted to a hospital. Residents who needed extensive assistance or were completely dependent in their functional domains had pressure ulcers, deteriorated mood or lower cognitive performance scale scores. These residents experienced higher chances of hospital transfer. However, a deteriorated ADL played a significant role in all multivariate models, indicating that a decline in ADL is a stronger predictor of hospital transfer than other functional or clinical predictors. Conclusion: Although all functional impairments and chronic medical illness can be associated with hospital transfer, functional decline may be the most important predictor of hospital transfer in patients newly admitted to an SNF

Sequential Bilateral Lung Resection in a Patient with Mycobacterium Abscessus Lung Disease Refractory to Medical Treatment

Mycobacterium abscessus (M. abscessus) is the second most common nontuberculous mycobacteria (NTM) in South Korea. Nevertheless, the diagnosis and treatment of M. abscessus lung disease can be problematic. Surgical resection has been tried for patients with localized M. abscessus lung disease refractory to medical treatment. Here, we report on a 25-year-old woman with M. abscessus lung disease who had been diagnosed and treated three times for pulmonary tuberculosis. She was initially diagnosed as having M. intracellulare lung disease; however, M. abscessus was isolated after several months of medication. She had multiple bronchiectatic and cavitary lesions bilaterally, and M. abscessus was repeatedly isolated from her sputa despite prolonged treatment with clarithromycin, ethambutol, moxifloxacin, and amikacin. She improved only after sequential bilateral lung resection. Based on the experience with this patient, we suggest that, if medical treatment fails, surgical resection of a diseased lung should be considered even in patients with bilateral lesions

An Unusual Case of Carcinoma Erysipelatoides Originating from Gastric Adenocarcinoma

Carcinoma erysipelatoides, also known as inflammatory metastatic carcinoma, is a rare form of cutaneous metastasis. It is most commonly caused by breast carcinoma, but rarely associated with gastric adenocarcinoma. Herein, we report an unusual case of carcinoma erysipelatoides in a 55 year-old female who had been diagnosed with signet ring cell carcinoma of the stomach metastasizing to ovaries