Ultrafast strain engineering in complex oxide heterostructures

We report on ultrafast optical experiments in which femtosecond midinfrared radiation is used to excite the lattice of complex oxide heterostructures. By tuning the excitation energy to a vibrational mode of the substrate, a long-lived five-order-of-magnitude increase of the electrical conductivity of NdNiO(3) epitaxial thin films is observed as a structural distortion propagates across the interface. Vibrational excitation, extended here to a wide class of heterostructures and interfaces, may be conducive to new strategies for electronic phase control at THz repetition rates.

Lentivirus shRNA Grb10 targeting the pancreas induces apoptosis and improved glucose tolerance due to decreased plasma glucagon levels

AIMS/HYPOTHESIS

The physiological significance of growth factor receptor-bound protein-10 (GRB10) in the pancreas is unclear. We hypothesised that GRB10 is involved in pancreatic apoptosis, as GRB10 binds with a family of cell-survival-related proteins implicated in apoptosis.

METHODS

Lentiviral vector small hairpin RNA (shRNA) targeting Grb10 was injected in vivo via an intraductal pancreatic route to target pancreatic tissues in adult mice, which were studied 2 weeks post-injection.

RESULTS

Using the TUNEL assay, we demonstrated for the first time that in vivo injection of lentivirus shRNA Grb10 directly into the adult mouse pancreas induced apoptosis in both exocrine and endocrine (alpha and beta) cells. This effect was more pronounced in alpha cells. Levels of the pro-apoptotic protein BCL2-interacting mediator of cell death (BIM) in islets was higher in lentivirus shRNA Grb10 than in lentivirus shRNA scramble mice. In the apoptotic pathway, BIM initiates apoptosis signalling, leading to activation of the caspase cascade. We propose that, when complexed with GRB10, BIM is inactive. On activation by stress signalling or, in the present study, following injection of lentivirus shRNA Grb10 into pancreas, BIM becomes unbound from GRB10 and activates the caspase cascade. Indeed, caspase-3 activity in islets was higher in the experimental than in the control group. Apoptosis induced by shRNA Grb10 resulted in a 34% decrease in fasting plasma glucagon. Mice injected with shRNA Grb10 had improved glucose tolerance despite reduced insulin secretion compared with shRNA scramble control mice.

CONCLUSIONS/INTERPRETATION

GRB10 is critically involved in alpha cell survival and, as a result, plays an important role in regulating basal glucagon secretion and glucose tolerance in adult mice.

Indoor air pollution and lung function growth among children in four Chinese cities

Ambient air pollution has been associated with decreased growth in lung function among children; but little is known about the impact of indoor air pollution. We examined relationships between indoor air pollution metrics and lung function growth, among children (n = 3273) aged 6-13 years living in four Chinese cities. Lung function parameters (FVC and FEV(1) ) were measured twice a year. Questionnaires were used to determine home coal burning and ventilation practices. Generalized estimating equations were used to examine associations. Use of coal as a household fuel was associated with 16.5 ml/year lower (33%, P < 0.001) and 20.5 ml/year lower (39%, P < 0.001) growth in children's FEV(1) and FVC, respectively. FEV(1) growth was 10.2 ml/year higher (20%, P = 0.009), and FVC growth was 17.0 ml/year higher (33%, P < 0.001) among children who lived in houses with the presence of a ventilation device. Among children living in houses where coal was used as a fuel and no ventilation devices were present, adjusted FVC and FEV(1) growth, respectively, were 37% and 61% that of the average growth per year in the full cohort. This suggests that household coal use may cause deficits in lung function growth, while using ventilation devices may be protective of lung development.

PRACTICAL IMPLICATIONS

Nearly 3.4 billion people use solid fuels in homes for cooking and/or heating. We report the following findings from a longitudinal study: (i) household coal use is significantly associated with reduction in children's lung function growth and (ii) the use of household ventilation devices is significantly associated with higher lung function growth, particularly among children living in households where coal is used as a fuel. These findings not only provide evidence that indoor coal use impairs children's lung development but also point to the importance of improving ventilation conditions in reducing harmful effects of indoor air pollution sources.

Expression and prognostic relevance of p21WAF1 in stage III esophageal squamous cell carcinoma

The prognostic effect of p21(WAF1) expression on esophageal squamous cell carcinoma patients is controversial. Further clarifying the effect of this protein is beneficial for optimizing the patient outcomes. In the current study, we investigated the expression of p21(WAF1) protein in 189 specimens of stage III ESCC by immunohistochemistry. As shown by the Kaplan-Meier curve, the overall survival rate of the positive-expression group was significantly higher than that of the negative-expression group (P < 0.05). No significant correlation was observed between p21(WAF1) expression and clinicopathological parameters in terms of gender, age, tumor location, tumor grade, pathological stage, and number of regional lymph node metastases (P > 0.05). We concluded that p21(WAF1) played an intricate role in the tumorigenesis and development of ESCC. p21(WAF1) could serve as a positive prognostic predictor for stage III ESCC patients.

Plasma biomarkers of depressive symptoms in older adults

The pathophysiology of negative affect states in older adults is complex, and a host of central nervous system and peripheral systemic mechanisms may play primary or contributing roles. We conducted an unbiased analysis of 146 plasma analytes in a multiplex biochemical biomarker study in relation to number of depressive symptoms endorsed by 566 participants in the Alzheimer's Disease Neuroimaging Initiative (ADNI) at their baseline and 1-year assessments. Analytes that were most highly associated with depressive symptoms included hepatocyte growth factor, insulin polypeptides, pregnancy-associated plasma protein-A and vascular endothelial growth factor. Separate regression models assessed contributions of past history of psychiatric illness, antidepressant or other psychotropic medicine, apolipoprotein E genotype, body mass index, serum glucose and cerebrospinal fluid (CSF) τ and amyloid levels, and none of these values significantly attenuated the main effects of the candidate analyte levels for depressive symptoms score. Ensemble machine learning with Random Forests found good accuracy (~80%) in classifying groups with and without depressive symptoms. These data begin to identify biochemical biomarkers of depressive symptoms in older adults that may be useful in investigations of pathophysiological mechanisms of depression in aging and neurodegenerative dementias and as targets of novel treatment approaches.

Nanoimprint of dehydrated PEDOT:PSS for organic photovoltaics

We demonstrate the fabrication of poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) nanogratings by a dehydration-assisted nanoimprint lithographic technique. Dehydration of PEDOT:PSS increases its cohesion to protect the nanostructures formed by nanoimprinting during demolding, resulting in the formation of high quality nanogratings of 60 nm in height, 70 nm in width and 70 nm in spacing (aspect ratio of 0.86). PEDOT:PSS nanogratings are used as hole transport and an electron blocking layer in blended poly(3-hexylthiophene-2,5-diyl) (P3HT):[6,6]-penyl-C61-butyric-acid-methyl-ester (PCBM) organic photovoltaic devices (OPV), showing enhancement of photocurrent and power efficiency in comparison to OPV devices with non-patterned PEDOT:PSS films.

Surgery for movement disorders

Over past three decades, there has been a resurgence of interest in functional neurosurgery for movement disorders. Recently, thanks to the increased understanding of cellular pathophysiology and advances in technology and surgical techniques, deep brain stimulation (DBS) has essentially replaced ablative procedures for most of these conditions. Success of DBS treatment in the movement disorders depends on the recognized limitations in the medical treatment, our understanding of the anatomy and physiology of these disorders and, particularly, involvement of neurologists, neurosurgeons, clinical neurophysiologists and neuropsychiatrists in outcome studies of DBS surgery. Up to now, the exact mechanism of DBS is not fully understood. This review provides an overview of use of stereotactic neurosurgery, particularly DBS, for movement disorders, focusing mainly on the patient selection, target options, clinical outcome, adverse effects and possible mechanisms of DBS for advanced Parkinson's disease, dystonia, and essential tremor.

Coherent control of high harmonic generation via dual-gas multijet arrays

High harmonic generation (HHG) is a central driver of the rapidly growing field of ultrafast science. We present a novel quasiphase-matching (QPM) concept with a dual-gas multijet target leading, for the first time, to remarkable phase control between multiple HHG sources (>2) within the Rayleigh range. The alternating jet structure with driving and matching zones shows perfect coherent buildup for up to six QPM periods. Although not in the focus of the proof-of-principle studies presented here, we achieved competitive conversion efficiencies already in this early stage of development.

Effect of downregulated β-catenin on cell proliferative activity, the sensitivity to chemotherapy drug and tumorigenicity of ovarian cancer cells

The role of Wnt/β-catenin signaling pathway in the etiology and/or progression of ovarian cancer has been well documented. It was demonstrated that ovarian cancer constantly exhibit constitutive activation of canonical Wnt signaling, usually as a result of oncogenic mutations that stabilize and dysregulate the β-catenin protein. In this study, we transfected an expression vector-based small hairpin RNA (shRNA) targeting to β-catenin encoding gene into human A2780 ovarian cancer cells to investigate the effects of β-catenin knockdown on biological characteristics of ovarian cancer cells. The results showed that β-catenin shRNA expression resulted in decreased β-catenin mRNA and protein expression in the transfected A2780 cells, inhibition of cellular proliferation, decreased capability of clonogenicity in the plating and the soft agar, and increased sensitivities to chemotherapy drugs vincristine, paclitaxel and cisplatin compared to untransfected cells. Importantly, we found that shRNA-mediated knockdown of β-catenin strongly decreases tumour growth of human A2780 ovarian cancer cells in xenografts. These results demonstrate that β-catenin might be an effective therapeutic target for human ovarian cancer treatment.

A Two-Step Optimization Method for Improving Multiple Brain Lesion Treatments with Robotic Radiosurgery

Planning robotic radiosurgery treatments for multiple (n > 3) metastatic brain lesions is challenging due to the need of satisfying a large number of dose-volume constraints and the requirement of prescribing different dose levels to individual targets. In this study, we developed a sequential two-step optimization technique to improve the planning quality of such treatments. In contrast to the conventional approach of where all targets are simultaneously planned, we have developed a two-step optimization method. In this method, the first step was to create treatment plans for individual targets. In the second step, the 3D dose matrices associated with each plan were exported to Dicom-RT digital files and subsequently optimized. For the optimization, a singular-value-decomposition (SVD) algorithm was implemented to minimize the dose interferences among different targets. Finally, we compared the optimized treatment plans with the treatment plans created using the conventional method to determine the effectiveness of the new method. Large improvements in target dose distributions as well as normal brain sparing were found for the two-step optimization treatment plans as compared with the conventional treatment plans. The two-step optimization significantly lowered the volume of normal brain receiving relatively low doses. For example, the normal brain volume receiving 12-Gy was reduced by averaged 42% (range 34%–47%) with the two-step optimization. Such improvements generally enlarged with increasing number of targets being treated regardless of target sizes. Of note, normal brain dose was found to increase non-linearly with increasing number of targets. In summary, a two-step optimization technique is demonstrated to significantly improve the treatment plan quality as well as reduce the planning effort for multi-target robotic radiosurgery.