Simulations of nanocrystals under pressure : combining electronic enthalpy and linear-scaling density-functional theory

We present an implementation in a linear-scaling density-functional theory code of an electronic enthalpy method, which has been found to benatural and efficient for the ab initio calculation of finite systems underhydrostatic pressure. Based on a definition of the system volume as that enclosed within anelectronic density isosurface [M. Cococcioni, F. Mauri,G. Ceder, and N. Marzari, Phys. Rev. Lett.94, 145501 (2005)], it supports bothgeometry optimizations and molecular dynamics simulations. We introduce an approach for calibratingthe parameters defining the volume in the context of geometry optimizations and discuss theirsignificance. Results in good agreement with simulations using explicit solvents are obtained, validating ourapproach. Size-dependent pressure-induced structural transformations andvariations in the energy gap of hydrogenated silicon nanocrystals areinvestigated, including one comparable in size to recent experiments. A detailed analysis of thepolyamorphic transformationsreveals three types of amorphous structures and theirpersistence on depressurization is assessed

Open Versus Laparoscopic Adrenalectomy for Adrenocortical Carcinoma: A Meta-analysis of Surgical and Oncological Outcomes

PURPOSE: This study was designed to determine the role of laparoscopic adrenalectomy (LA) in the surgical management of adrenocortical carcinoma (ACC). METHODS: A systematic literature review was performed on January 2, 2015 using PubMed. Article selection proceeded according to PRISMA criteria. Studies comparing open adrenalectomy (OA) to LA for ACC and including at least 10 cases per each surgical approach were included. Odds ratio (OR) was used for all binary variables, and weight mean difference (WMD) was used for the continuous parameters. Pooled estimates were calculated with the fixed-effect model, if no significant heterogeneity was identified; alternatively, the random-effect model was used when significant heterogeneity was detected. Main demographics, surgical outcomes, and oncological outcomes were analyzed. RESULTS: Nine studies published between 2010 and 2014 were deemed eligible and included in the analysis, all of them being retrospective case-control studies. Overall, they included 240 LA and 557 OA cases. Tumors treated with laparoscopy were significantly smaller in size (WMD -3.41 cm; confidence interval [CI] -4.91, -1.91; p < 0.001), and a higher proportion of them (80.8 %) more at a localized (I-II) stage compared with open surgery (67.7 %) (odds ratio [OR] 2.8; CI 1.8, 4.2; p < 0.001). Hospitalization time was in favor of laparoscopy, with a WMD of -2.5 days (CI -3.3, -1.7; p < 0.001). There was no difference in the overall recurrence rate between LA and OA (relative risk [RR] 1.09; CI 0.83, 1.43; p = 0.53), whereas development of peritoneal carcinomatosis was higher for LA (RR 2.39; CI 1.41, 4.04; p = 0.001). No difference could be found for time to recurrence (WMD -8.2 months; CI -18.2, 1.7; p = 0.11), as well as for cancer specific mortality (OR 0.68; CI 0.44, 1.05; p = 0.08). CONCLUSIONS: OA should still be considered the standard surgical management of ACC. LA can offer a shorter hospital stay and possibly a faster recovery. Therefore, this minimally invasive approach can certainly play a role in this setting, but it should be only offered in carefully selected cases to avoid jeopardizing the oncological outcome.PURPOSE: This study was designed to determine the role of laparoscopic adrenalectomy (LA) in the surgical management of adrenocortical carcinoma (ACC). METHODS: A systematic literature review was performed on January 2, 2015 using PubMed. Article selection proceeded according to PRISMA criteria. Studies comparing open adrenalectomy (OA) to LA for ACC and including at least 10 cases per each surgical approach were included. Odds ratio (OR) was used for all binary variables, and weight mean difference (WMD) was used for the continuous parameters. Pooled estimates were calculated with the fixed-effect model, if no significant heterogeneity was identified; alternatively, the random-effect model was used when significant heterogeneity was detected. Main demographics, surgical outcomes, and oncological outcomes were analyzed. RESULTS: Nine studies published between 2010 and 2014 were deemed eligible and included in the analysis, all of them being retrospective case-control studies. Overall, they included 240 LA and 557 OA cases. Tumors treated with laparoscopy were significantly smaller in size (WMD -3.41 cm; confidence interval [CI] -4.91, -1.91; p < 0.001), and a higher proportion of them (80.8 %) more at a localized (I-II) stage compared with open surgery (67.7 %) (odds ratio [OR] 2.8; CI 1.8, 4.2; p < 0.001). Hospitalization time was in favor of laparoscopy, with a WMD of -2.5 days (CI -3.3, -1.7; p < 0.001). There was no difference in the overall recurrence rate between LA and OA (relative risk [RR] 1.09; CI 0.83, 1.43; p = 0.53), whereas development of peritoneal carcinomatosis was higher for LA (RR 2.39; CI 1.41, 4.04; p = 0.001). No difference could be found for time to recurrence (WMD -8.2 months; CI -18.2, 1.7; p = 0.11), as well as for cancer specific mortality (OR 0.68; CI 0.44, 1.05; p = 0.08). CONCLUSIONS: OA should still be considered the standard surgical management of ACC. LA can offer a shorter hospital stay and possibly a faster recovery. Therefore, this minimally invasive approach can certainly play a role in this setting, but it should be only offered in carefully selected cases to avoid jeopardizing the oncological outcome

ALDH Activity Correlates with Metastatic Potential in Primary Sarcomas of Bone.

Osteosarcoma (OS), chondrosarcoma (CSA), and Ewings sarcoma (ES) are the most common primary malignancies of bone, and are rare diseases. As with all sarcomas, the prognosis of these diseases ultimately depends on the presence of metastatic disease. Survival is therefore closely linked with the biology and metastatic potential of a particular bone tumor's cells. Here we describe a significant correlation of aldehyde dehydrogenase (ALDH) activity and the presence/absence of distant metastases in ten consecutive cases of human bone sarcomas. Additionally, cultured human CSA cells, which are historically chemo- and radio-resistant, may be sensitive to the ALDH inhibitor, disulfiram. While it is premature to draw broad conclusions from such a small series, the importance of ALDH activity and inhibition in the metastatic potential of primary bone sarcomas should be investigated further

Synthesis and Characterization of Novel Electrode Material for Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries are becoming increasingly attractive as one of the most promising advanced secondary batteries with overwhelming advantages of high theoretical capacity (1675 mAh/g) and high energy density (2600 VS. 420 W h/kg of traditional Li-ion batteries). Sulfur is one of the most abundant elements on earth and is an underutilized byproduct from the oil and gas industries. Additionally, in comparison to Li-ion batteries, Li-S batteries have improved safety and lower cost. They are also more environmentally friendly. However, the predominant challenge with lithium-sulfur batteries is capacity drop and low cycle life during usage of the sulfur-based electrode. This project aims to solve this problem by careful design of carbon based nanomaterials to physically and/or chemically confine the sulfur component. Developing the sulfur/carbon nanocomposite will be conducted using well-studied synthesis processes. Characterization of the electrodes will be conducted through analytical techniques via scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), x-ray diffraction (XRD), scanning tunneling microscopy (STM), and atomic force microscopy (AFM). Electrochemical evaluation of assembled split cell will consist of cyclability and rate capability testing using the electrochemical testing station. The expected outcome is to achieve high performance of Li-S batteries with long cycle life and maintaining high specific capacity, a goal for emerging advanced energy storage technology, portable electronics, and grid-scale energy station

A hall plate based instrument to measure the snapback in the Large Hadron Collider superconducting dipole magnets

The decay and snapback of the magnetic field multipoles in superconducting particle accelerators like the Large Hadron Collider (LHC) could result in a significant particle beam loss unless adequately compensated. Whilst standard instrumentation used to measure the field quality of the superconducting magnets is good enough to measure the harmonic decay, it is not fast enough to measure the snapback. Therefore, a state of the art instrument was recently developed at CERN to measure the most important harmonics with a high measurement frequency and hence improve the understanding of the snapback phenomenon. In this paper we describe the instrument's principle of operation, its mechanical arrangement, its compensation system and its digital acquisition system. We also compare the performance of two different techniques implemented to achieve the necessary measurement resolution of 6 orders of magnitude lower than the main superimposed dipole field.peer-reviewe

Identification and Characterization of the Expression Profile of Oligodendrocyte-Derived and Associated Proteins via Unilateral X-Irradation of the Rat Optic Nerve

Recent studies examining cell-cell interactions during CNS development and following disease or trauma have highlighted our limited understanding of the in vivo functions of the myelinating cell of the CNS, the oligodendrocyte. With this in mind, our laboratory has developed techniques by which a profile of proteins derived from or regulated by oligodendrocytes can be elucidated. Specifically, we have demonstrated that oligodendrocytes can be selectively eliminated from one optic nerve of a rat by treating the animal with a unilateral exposure of X-irradiation at the time of birth. Consequently, this approach allowed us to experimentally create, within the same animal, one optic nerve devoid of oligodendrocytes and their progenitors (the X- irradiated side) and one optic nerve containing the normal oligodendrocyte population (the untreated side). Using this experimental animal model we hypothesized that uncharacterized proteins, derived from and regulated by oligodendrocytes, which are crucial for CNS development can be identified. Specifically, by comparing protein profiles found within the normal myelinating optic nerve versus the X-irradiated optic nerve, where oligodendrocytes are absent, potential oligodendrocyte-derived proteins can be quickly identified. Further verification that these proteins are indeed related to oligodendrocytes and/or the processes of myelination can be obtained by their reappearance in the 2-D gel protein profile of P28 X-irradiated nerves that, as we have shown previously, undergo a delayed myelination. We then employed mass spectrometric analysis to determine the identities of oligodendrocyte derivedregulated proteins. In this thesis, I will begin by describing our current knowledge of the proteins expressed by oligodendrocytes and their role(s) in oligodendrocyte function. This will be followed by a detailed description of the experimental model system we utilized in an attempt to elucidate the complete repertoire of oligodendrocyte-regulated proteins. We will then describe the results generated fiom our methodology and discuss the implications of our findings in relation to the functional cooperation between oligodendrocytes and other cells of the developing central nervous system. The results generated fiom this project should lead to a clearer understanding of the role of oligodendrocytes and\u27of the array of proteins whose expression patterns are associated with these cells during CNS development

Scott Calhoun, U2 and the Religious Impulse: Take Me Higher

Does the world need another edited collection on the Irish rock band, U2? Maybe not. After all, the band have gained enough commercial success and garnered enough attention already. They have received so much visibility that it has gone to their collective rock star heads. Bono, the band’s lead singer and, arguably, the biggest ego of the group, has used (and perhaps abused) his cultural capital to mingle with those with political capital (not to mention monetary capital) to try to affect cha..

Sleep-wake sensitive mechanisms of adenosine release in the basal forebrain of rodents : an in vitro study

Adenosine acting in the basal forebrain is a key mediator of sleep homeostasis. Extracellular adenosine concentrations increase during wakefulness, especially during prolonged wakefulness and lead to increased sleep pressure and subsequent rebound sleep. The release of endogenous adenosine during the sleep-wake cycle has mainly been studied in vivo with microdialysis techniques. The biochemical changes that accompany sleep-wake status may be preserved in vitro. We have therefore used adenosine-sensitive biosensors in slices of the basal forebrain (BFB) to study both depolarization-evoked adenosine release and the steady state adenosine tone in rats, mice and hamsters. Adenosine release was evoked by high K+, AMPA, NMDA and mGlu receptor agonists, but not by other transmitters associated with wakefulness such as orexin, histamine or neurotensin. Evoked and basal adenosine release in the BFB in vitro exhibited three key features: the magnitude of each varied systematically with the diurnal time at which the animal was sacrificed; sleep deprivation prior to sacrifice greatly increased both evoked adenosine release and the basal tone; and the enhancement of evoked adenosine release and basal tone resulting from sleep deprivation was reversed by the inducible nitric oxide synthase (iNOS) inhibitor, 1400 W. These data indicate that characteristics of adenosine release recorded in the BFB in vitro reflect those that have been linked in vivo to the homeostatic control of sleep. Our results provide methodologically independent support for a key role for induction of iNOS as a trigger for enhanced adenosine release following sleep deprivation and suggest that this induction may constitute a biochemical memory of this state