Surface properties of AlInGaN/GaN heterostructure

Surface structural, electronic and electrical properties of the quaternary alloy AlInGaN/GaN heterostructures are investigated. Surface termination, atomic arrangement, electronic and electrical properties of the (0001) surface and (10-11) V-defect facets have been experimentally analyzed using various surface sensitive techniques including spectroscopy and microscopy. Moreover, the effect of sub-band gap (of the barrier layer) illumination on contact potential difference (VCPD) and the role of oxygen chemisorption have been studied

Statistical process control of mortality series in the Australian and New Zealand Intensive Care Society (ANZICS) adult patient database: implications of the data generating process

for the ANZICS Centre for Outcome and Resource Evaluation (CORE) of the Australian and New Zealand Intensive Care Society (ANZICS)BACKGROUND Statistical process control (SPC), an industrial sphere initiative, has recently been applied in health care and public health surveillance. SPC methods assume independent observations and process autocorrelation has been associated with increase in false alarm frequency. METHODS Monthly mean raw mortality (at hospital discharge) time series, 1995–2009, at the individual Intensive Care unit (ICU) level, were generated from the Australia and New Zealand Intensive Care Society adult patient database. Evidence for series (i) autocorrelation and seasonality was demonstrated using (partial)-autocorrelation ((P)ACF) function displays and classical series decomposition and (ii) “in-control” status was sought using risk-adjusted (RA) exponentially weighted moving average (EWMA) control limits (3 sigma). Risk adjustment was achieved using a random coefficient (intercept as ICU site and slope as APACHE III score) logistic regression model, generating an expected mortality series. Application of time-series to an exemplar complete ICU series (1995-(end)2009) was via Box-Jenkins methodology: autoregressive moving average (ARMA) and (G)ARCH ((Generalised) Autoregressive Conditional Heteroscedasticity) models, the latter addressing volatility of the series variance. RESULTS The overall data set, 1995-2009, consisted of 491324 records from 137 ICU sites; average raw mortality was 14.07%; average(SD) raw and expected mortalities ranged from 0.012(0.113) and 0.013(0.045) to 0.296(0.457) and 0.278(0.247) respectively. For the raw mortality series: 71 sites had continuous data for assessment up to or beyond lag ₄₀ and 35% had autocorrelation through to lag ₄₀; and of 36 sites with continuous data for ≥ 72 months, all demonstrated marked seasonality. Similar numbers and percentages were seen with the expected series. Out-of-control signalling was evident for the raw mortality series with respect to RA-EWMA control limits; a seasonal ARMA model, with GARCH effects, displayed white-noise residuals which were in-control with respect to EWMA control limits and one-step prediction error limits (3SE). The expected series was modelled with a multiplicative seasonal autoregressive model. CONCLUSIONS The data generating process of monthly raw mortality series at the ICU level displayed autocorrelation, seasonality and volatility. False-positive signalling of the raw mortality series was evident with respect to RA-EWMA control limits. A time series approach using residual control charts resolved these issues.John L Moran, Patricia J Solomo

Анализ экспрессии матричной РНК панели генов морфологически неизмененного эпителия прямой кишки как метод ранней диагностики патологии толстой кишки

Introduction. The absence of specific clinical symptoms in the early stages of colorectal cancer development leads to the fact that a quarter of patients who seek help for the first time have a metastatic stage of the disease. For the timely detection of pre-tumor disorders or hidden foci of malignancy, the possibilities of modern molecular biological technologies are being actively studied today.Aim. To develop a method for diagnosing tumor diseases of the colon based on molecular genetic analysis of morphologically unchanged intestinal epithelium distant from the focus of the tumor lesion.Materials and methods. We examined the matrix RNA (mRNA)  expression profile of 63 candidate genes potentially associated with the pathogenesis of neoplastic changes in rectal mucosal samples. Samples were obtained during prophylactic and/or diagnostic video colonoscopy of 122 patients, 41 of whom had no history of breast cancer (“Normal”), 32 patients were diagnosed with breast cancer polyps (“Polyposis”) and 49 patients were diagnosed with breast cancer (“colorectal cancer”). mRNA expression was assessed by reverse transcription polymerase chain reaction.Results. Using the discriminant analysis method, it was established that  the cellular material of scrapings from the rectum in the “colorectal cancer” group reliably, with a classification accuracy above 96 %, differs in expression phenotype from the “Normal” and “Polyposis” groups.Conclusion. The data obtained are a prerequisite for the development of a minimally invasive diagnostic method that can be used as part of an outpatient  examination to assess the risk of colon tumor disease.Введение. Отсутствие специфических  клинических симптомов на ранних стадиях развития колоректального рака приводит к тому, что четверть пациентов, впервые обращающихся за помощью, имеют метастатическую стадию заболевания. Для своевременного обнаружения предопухолевых нарушений или скрытых очагов малигнизации сегодня активно изучаются возможности современных молекулярно-биологических технологий.Цель исследования – разработка метода диагностики опухолевых заболеваний толстой кишки на основе молекулярно-генетического анализа морфологически неизмененного кишечного эпителия, отдаленного от очага опухолевого поражения.Материалы и методы. Исследован профиль экспрессии матричной РНК (мРНК) 63 генов-кандидатов, потенциально связанных с патогенезом неопластических изменений, в образцах слизистой оболочки прямой кишки. Образцы получены в ходе профилактической и/или диагностической видеоколоноскопии 122 пациентов, из которых у 41 в анамнезе не было заболеваний толстой кишки (группа «Норма»), у 32 – установлен диагноз «полипы толстой кишки» (группа «полипоз»), у 49 – диагноз «карцинома толстой кишки» (группа «колоректальный рак»). Экспрессию мРНК оценивали методом полимеразной цепной реакции с обратной транскрипцией.Результаты. С помощью дискриминантного  анализа установлено, что клеточный материал соскобов из прямой кишки в группе колоректального рака достоверно, с точностью выше 96 %, отличается  по экспрессионному фенотипу от групп нормы и полипоза.Заключение. Полученные данные являются предпосылкой к разработке малоинвазивного метода диагностики, который может быть использован в рамках амбулаторного обследования для оценки риска наличия опухолевого заболевания толстой кишки