Surface-step-terrace-induced anomalous transport properties in highly epitaxial La0.67Ca0.33MnO3 thin films

La0.67Ca0.33MnO3 thin films were epitaxially grown on miscut MgO(001) substrates by pulsed laser ablation. Electrical transport properties were studied by using an ultra high vacuum, four-probe STM system at different temperatures. Anomalous resistivity behavior and metal-insulator transition temperatures were found, both of which are highly dependent upon the miscut angle (1, 3, and 5°). These phenomena are attributed to the difference in residual strain that results from the difference in terrace widths of the vicinal surfaces.

YAP dysregulation by phosphorylation or ΔNp63-mediated gene repression promotes proliferation, survival and migration in head and neck cancer subsets

Over-expression of Yes-associated protein (YAP), and TP53 family members ΔNp63 and p73 with which YAP may serve as a nuclear co-factor, have been independently detected in subsets of head and neck squamous cell carcinomas (HNSCC). Their potential relationship and functional role of YAP in HNSCC are unknown. Here we reveal that in a subset of HNSCC lines and tumors, YAP expression is increased but localized in the cytoplasm in association with increased AKT and YAP phosphorylation, and decreased expression of ΔNp63 and p73. Conversely, YAP expression is decreased but detectable in the nucleus in association with lower AKT and YAP phosphorylation, and increased ΔNp63 and p73 expression, in another subset. Inhibiting AKT decreased Serine-127 phosphorylation and enhanced nuclear translocation of YAP. ΔNp63 repressed YAP expression and bound its promoter. Transfection of a YAP-Serine-127-Alanine phosphoacceptor-site mutant or ΔNp63 knockdown significantly increased nuclear YAP and cell death. Conversely, YAP knockdown enhanced cell proliferation, survival, migration, and cisplatin chemoresistance. Thus, YAP function as a tumor suppressor may alternatively be dysregulated by AKT phosphorylation at Serine-127 and cytoplasmic sequestration, or by transcriptional repression by ΔNp63, in different subsets of HNSCC. AKT and/orΔNp63 are potential targets for enhancing YAP-mediated apoptosis and chemosensitivity in HNSCC.

Radiometric dating of the late Quaternary summer monsoon on the Loess Plateau, China

Recent advances in radiometric dating have enabled independent investigation into monsoon variations. In this study, summer monsoon pedogenesis proxies (CaCO3 and magnetic susceptibility) have been analysed by optically stimulated luminescence (OSL) age for five loess-palaeosol sections over the Chinese Loess Plateau. The use of CaCO3 is complicated by the multiple influences on its variation. However, changes in magnetic susceptibility can be used as a proxy for summer monsoon induced pedogenesis. The data suggest that the summer monsoon in north-central China is not prone to high frequency shifts, although abrupt transitions occur. The overall patterns show general decreasing trends from c. 50 to 18 ka. However, between 9 and 6 ka, magnetic susceptibility increases abruptly and dramatically at the sites. These findings suggest that the Holocene ‘optimum’ in the region may be a more recent phenomenon than previously suggested, and that this summer monsoon intensity increase significantly post-dates the insolation peak occurring at 11.5 ka. An apparent close correspondence to ice volume is suggested to be a consequence of forcing via atmospheric circulation. Independently dated records that employ high sampling resolution can be used to test this hypothesis, together with suggestions over the apparent lag between insolation forcing and monsoon response.

Aeolian sediment evidence that global cooling has driven late Cenozoic stepwise aridification in central Asia

It has been a long held view that uplift of the Tibetan Plateau dominated stepwise climatic drying in central Asia during the late Cenozoic. On the other hand, global cooling may also have forced Asian drying and the subsequent formation of aeolian deposits in north China. Until now, whether the Tibetan uplift or the global cooling has been the first-order driver controlling stepwise Asian drying has remained a contentious issue. In this study, we examine the thick aeolian silt deposit, which is regarded as a good archive of palaeoclimatic changes in central Asia and north China, in order to qualitatively reconstruct the drying process in Asia during the late Cenozoic. On the basis of our long-term field surveys, laboratory analyses and previous investigations, we have obtained time sequences of Asian drying from the early Miocene to late Pleistocene; we compare this newly reconstructed time series of Asian aridification with the time series of global cooling and Tibetan uplift to identify the first-order driver of stepwise Asian aridification. A good match between the drying and global cooling might indicate that global cooling was the most likely driver of stepwise drying in interior Asia. On the other hand, controversy regarding timing and amplitude of Tibetan uplift during the late Cenozoic suggests that the prevailing conclusion that Tibetan uplift forces Asian drying should be regarded as immature. A mechanism that global cooling drove the Asian drying is tentatively suggested.

In Vitro Bond Strengths of Amalgam Added to Existing Amalgams

Freshly mixed amalgam added to existing amalgam restorations as a means of repair and allowed to set completely may be expected to join with nearly original strength, if sufficient condensation time and pressure are used.

Discharge after discharge: predicting surgical site infections after patients leave hospital

In this population-based retrospective cohort study, we examined the frequency, severity, and prediction of post-discharge surgical site infections (SSIs). We evaluated all patients admitted for their first elective surgical procedure in Ontario, Canada, between 1 April 2002 and 31 March 2008. Procedure and patient characteristics were derived from linked hospital, emergency room and physician claims databases within Canada's universal healthcare system. The 30 day risk of SSI was derived from the initial hospital admission, outpatient consultations, return emergency room visits and readmissions. The cohort included 622 683 patients, of whom 84 081 (13.5%) were diagnosed with SSI, and more than half (48 725) were diagnosed post-discharge. Post-discharge infections were associated with an increased risk of reoperation (odds ratio: 2.28; 95% confidence interval: 2.11-2.48), return emergency room visit (9.08; 8.89-9.27), and readmission (6.16; 5.98-6.35). The most common risk index predicted incremental increases in the risk of in-hospital SSI, but did not predict increases in the risk of post-discharge infection. Patients with post-discharge infections had baseline characteristics more akin to uninfected patients than patients with in-hospital infections. Predictors of post-discharge infection included shorter procedure duration, shorter length of stay, rural residence, alcoholism, diabetes and obesity. Post-discharge SSIs are frequent, severe, scattered over time and location, and hard to predict using common risk indices. They represent an important hidden burden in our healthcare system.

Myocardial infarction associated with recency of immigration to Ontario

BACKGROUND

New immigrants to North America exhibit lower rates of obesity and hypertension than their native-born counterparts. Whether this is reflected by a lower relative risk of acute myocardial infarction (AMI) is not known.

OBJECTIVE

To determine the risk of AMI among new immigrants compared to long-term residents, and, among those who develop AMI, their short- and long-term mortality rate.

DESIGN

Population-based, matched, retrospective cohort study.

SETTING

Entire province of Ontario, the most populated province in Canada, from 1 April 1995 to 31 March 2007.

PARTICIPANTS

A total of 965,829 new immigrants were matched to 3,272,393 long-term residents by year of birth, sex and geographic location.

MEASUREMENTS

The main study outcome was hospitalization with a most responsible diagnosis of AMI. Secondary study outcomes among those who sustained an AMI were in-hospital, 30-day and 1-year mortality.

RESULTS

The mean age of the participants at study entry was approximately 34 years. The incidence rate of AMI was 4.14 per 10,000 person-years among new immigrants and 6.61 per 10,000 person-years among long-term residents. After adjusting for age, income quintile, urban vs. rural residence, history of hypertension, diabetes mellitus and smoking and number of health insurance claims, the hazard ratio for AMI was 0.66 [95% confidence interval (CI): 0.63-0.69].

CONCLUSION

New immigrants appear to be at lower risk of AMI than long-term residents. This finding does not appear to be explained by the availability of health-care services or income level.

Eutrophication of lake waters in China: cost, causes, and control

Lake water eutrophication has become one of the most important factors impeding sustainable economic development in China. Knowledge of the current status of lake water eutrophication and determination of its mechanism are prerequisites to devising a sound solution to the problem. Based on reviewing the literature, this paper elaborates on the evolutional process and current state of shallow inland lake water eutrophication in China. The mechanism of lake water eutrophication is explored from nutrient sources. In light of the identified mechanism strategies are proposed to control and tackle lake water eutrophication. This review reveals that water eutrophication in most lakes was initiated in the 1980s when the national economy underwent rapid development. At present, the problem of water eutrophication is still serious, with frequent occurrence of damaging algal blooms, which have disrupted the normal supply of drinking water in shore cities. Each destructive bloom caused a direct economic loss valued at billions of yuan. Nonpoint pollution sources, namely, waste discharge from agricultural fields and nutrients released from floor deposits, are identified as the two major sources of nitrogen and phosphorus. Therefore, all control and rehabilitation measures of lake water eutrophication should target these nutrient sources. Biological measures are recommended to rehabilitate eutrophied lake waters and restore the lake ecosystem in order to bring the problem under control.