Deposition of tin oxide,iridium and iridium oxide films by metal-organic chemical vapor deposition for electrochemical wastewater treatment

In this research, the specific electrodes were prepared by metal-organic chemical vapor deposition (MOCVD) in a hot-wall CVD reactor with the presence of O₂ under reduced pressure. The Ir protective layer was deposited by using (Methylcyclopentadienyl) (1,5-cyclooctadiene) iridium (I), (MeCp)Ir(COD), as precursor. Tetraethyltin (TET) was used as precursor for the deposition of SnO₂ active layer. The optimum condition for Ir film deposition was at 300 °C, 125 of O₂/(MeCp)Ir(COD) molar ratio and 12 Torr of total pressure. While that of SnO₂ active layer was at 380 °C, 1200 of O₂/TET molar ratio and 15 Torr of total pressure. The prepared SnO₂/Ir/Ti electrodes were tested for anodic oxidation of organic pollutant in a simple three-electrode electrochemical reactor using oxalic acid as model solution. The electrochemical experiments indicate that more than 80% of organic pollutant was removed after 2.1 Ah/L of charge has been applied. The kinetic investigation gives a two-step process for organic pollutant degradation, the kinetic was zero-order and first-order with respect to TOC of model solution for high and low TOC concentrations, respectively.     

Preclinical Evaluation of Sodium Selenite in Mice: Toxicological and Tumor Regression Studies after Striatum Implantation of Human Glioblastoma Stem Cells

Glioblastoma (GBM) is the most aggressive malignant glioma, with a very poor prognosis; as such, efforts to explore new treatments and GBM’s etiology are a priority. We previously described human GBM cells (R2J-GS) as exhibiting the properties of cancer stem cells (growing in serum-free medium and proliferating into nude mice when orthotopically grafted). Sodium selenite (SS)—an in vitro attractive agent for cancer therapy against GBM—was evaluated in R2J-GS cells. To go further, we launched a preclinical study: SS was given orally, in an escalation-dose study (2.25 to 10.125 mg/kg/day, 5 days on, 2 days off, and 5 days on), to evaluate (1) the absorption of selenium in plasma and organs (brain, kidney, liver, and lung) and (2) the SS toxicity. A 6.75 mg/kg SS dose was chosen to perform a tumor regression assay, followed by MRI, in R2J-GS cells orthotopically implanted in nude mice, as this dose was nontoxic and increased brain selenium concentration. A group receiving TMZ (5 mg/kg) was led in parallel. Although not reaching statistical significance, the group of mice treated with SS showed a slower tumor growth vs. the control group (p = 0.08). No difference was observed between the TMZ and control groups. We provide new insights of the mechanisms of SS and its possible use in chemotherapy.     

Sem observations of the microstructure of frost deteriorated and self-healed concretes

The microcracking and self healing mechanisms of concrete exposed to rapid freezing and thawing in water and subsequently kept in water have been investigated by Scanning Electron Microscopy (SEM). Non air entrained concretes of water/binder ratio 0.40 with 0 and 5 % silica fume were studied. Damage was measured as loss in resonance frequency and compressive strength. After frost exposure, concrete beams were stored three months in water. During this time resonance frequency largely recovered, whereas compressive strength showed smaller recovery. On Secondary Electron Images (SEI) of fractured surfaces hydration products mainly of the C-S-H type were seen traversing cracks at several locations after self healing, but not directly after freeze/thaw. Back Scattered Electron Images (BSEI) showed that the cracks due to freeze/thaw testing were of 1–10 μm width. The cracks traversed the paste and followed the interfaces of most larger aggregate particles. On BSEI self healing was seen on 300–1000 X magnification as partly closing of several cracks smaller than 5 μm. This was most clearly seen by switching between SEI and BSEI modes. In BSEI-mode the re-hydration products appeared less dense and the cracks appeared wider than in the SEI-mode.     

Collective response to perturbations in a data-driven fish school model

Fish schools are able to display a rich variety of collective states and behavioural responses when they are confronted by threats. However, a school''s response to perturbations may be different depending on the nature of its collective state. Here we use a previously developed data-driven fish school model to investigate how the school responds to perturbations depending on its different collective states, we measure its susceptibility to such perturbations, and exploit its relation with the intrinsic fluctuations in the school. In particular, we study how a single or a small number of perturbing individuals whose attraction and alignment parameters are different from those of the main population affect the long-term behaviour of a school. We find that the responsiveness of the school to the perturbations is maximum near the transition region between milling and schooling states where the school exhibits multistability and regularly shifts between these two states. It is also in this region that the susceptibility, and hence the fluctuations, of the polarization order parameter is maximal. We also find that a significant school''s response to a perturbation only happens below a certain threshold of the noise to social interactions ratio.     

A practical sequential lexicographic approach for derivative-free black-box constrained optimization

Many engineering optimization problems involve models that might not exhibit the necessary smoothness to warrant efficient use of gradient algorithms. Many of these problems are also subject to constraints that might be simulation-based and as costly to compute as the objective function. Traditionally, such problems are solved using either penalty methods or lexicographic ordering that evaluates aggregate constraints prior to computing objective values. This study describes a cost-effective approach to performing such optimizations. After classifying all constraints depending on their computational cost, points not satisfying linear constraints are feasibilized, and a suitable penalty term constructed. A sequential lexicographic ordering is then applied in which inexpensive nonlinear constraints take precedence over expensive ones, which in turn take precedence over objective function values. The performance advantage of the proposed method over traditional ones is demonstrated with a set of analytical test problems, and with oilfield-production optimization examples that use ‘black-box’ simulators.     

A Representation for Conceptual Design of Buildings

The building representation for storing design solutions adopted in SEED-Config consists of two levels of abstraction models defined on top of the object-oriented data model. The first level is an information model, called the building entity and technology model, which stores design data as they are generated during conceptual design, supports case-based reasoning, and shares data among all design participants. This model represents each building entity as a generic container that encompasses its properties, taxonomy, geometry, composition, relationships, and design knowledge applied in generating it. The second level is a conceptual model that defines the types of objects, relationships, and data needed to fully represent the information in a given design domain. The conceptual model specifies the semantics of the design information for the domain using the syntax defined in the information model. The proposed representation also includes a faceted classification scheme to define the controlled vocabulary from which indexes are obtained. The representation has the following advantages: It integrates multiple views, supports design evolution, supports design exploration, and is extensible.     

Revisiting gonadotrophin-releasing hormone agonist protocols and management of poor ovarian responses to gonadotrophins

Within the past decade, gonadotrophin-releasing hormone (GnRH) agonists have contributed greatly to the success of cycles programmed for in-vitro fertilization and embryo transfer. However, apart from a preventive effect on the luteinizing hormone (LH) surge, most of the beneficial effects of these molecules are still only partly known. A precise analysis of regimens using GnRH agonists for ovarian stimulation shows that many parameters may interfere with the outcome of long-term and short-term protocols. The great variability between these protocols hampers our comprehension of the mechanisms involved in the overall clinical improvement seen with this therapy. The hypophyseal desensitization induced by GnRH agonists is greatly dependent on the dose and duration of their administration, but the residual gonadotrophin secretion is imperfectly estimated by hormonal measurements using radioimmunometric assays. Moreover, the specific role of GnRH agonist-induced ovarian quiescence on subsequent ovarian responsiveness to gonadotrophins and on endometrial receptivity deserves further investigation. Finally, a direct ovarian action of GnRH agonists on steroidogenesis, folliculogenesis and embryo quality is still controversial in humans. These putative deleterious effects of GnRH agonists have led some authors to recommend a reduction of both dose and duration of GnRH agonist administration for women identified by a poor response to gonadotrophins. Using this approach, a few reports have recently shown some clinical advantages for ovarian responsiveness but no convincing evidence for any improvement in pregnancy rate. It thus appears that the overall impact of GnRH agonists on reproductive function is still partly misunderstood.     

GaInNAs-based Hellish-vertical cavity semiconductor optical amplifier for 1.3 μm operation

Hot electron light emission and lasing in semiconductor heterostructure (Hellish) devices are surface emitters the operation of which is based on the longitudinal injection of electrons and holes in the active region. These devices can be designed to be used as vertical cavity surface emitting laser or, as in this study, as a vertical cavity semiconductor optical amplifier (VCSOA). This study investigates the prospects for a Hellish VCSOA based on GaInNAs/GaAs material for operation in the 1.3-μm wavelength range. Hellish VCSOAs have increased functionality, and use undoped distributed Bragg reflectors; and this coupled with direct injection into the active region is expected to yield improvements in the gain and bandwidth. The design of the Hellish VCSOA is based on the transfer matrix method and the optical field distribution within the structure, where the determination of the position of quantum wells is crucial. A full assessment of Hellish VCSOAs has been performed in a device with eleven layers of Ga_0.35In_0.65N_0.02As_0.08/GaAs quantum wells (QWs) in the active region. It was characterised through I-V, L-V and by spectral photoluminescence, electroluminescence and electro-photoluminescence as a function of temperature and applied bias. Cavity resonance and gain peak curves have been calculated at different temperatures. Good agreement between experimental and theoretical results has been obtained.     

How different messaging semantics can affect SCA applications performances: a benchmark comparison

Software Communications Architecture (SCA) compliant radios typically contain a large number of software components. Some software components provide access to hardware devices while others perform signal processing. By interacting with each other, the software components implement a radio communications standard. To interact, the software components use a middleware called Common Object Request Broker Architecture (CORBA). Using CORBA, each interaction is carried out as an exchange of messages between two components. CORBA supports two main types of messaging: one-way and two-way. This article explores the differences between the two types of messaging and provides performance metrics. The article also describes design approaches that can be used to avoid common pitfalls associated with the use of both types of messaging.