Unsupervised learning of an atlas from unlabeled point-sets

One of the key challenges in deformable shape modeling is the problem of estimating a meaningful average or mean shape from a set of unlabeled shapes. We present a new joint clustering and matching algorithm that is capable of computing such a mean shape from multiple shape samples which are represented by unlabeled point-sets. An iterative bootstrap process is used wherein multiple shape sample point-sets are nonrigidly deformed to the emerging mean shape, with subsequent estimation of the mean shape based on these nonrigid alignments. The process is entirely symmetric with no bias toward any of the original shape sample point-sets. We believe that this method can be especially useful for creating atlases of various shapes present in medical images. We have applied the method to create mean shapes from nine hand-segmented 2D corpus callosum data sets and 10 hippocampal 3D point-sets.     

Heteroleptic thiolate diamine nickel complexes: Noble-free-metal catalysts in electrocatalytic and light-driven hydrogen evolution reaction

Three mononuclear heteroleptic nickel complexes bearing the non-innocent o-aminobenzenethiolate (2-amnt) ligand and different diamine ligands, namely, [Ni(2-amnt)(o-phen)] (o-phen = o-phenylenediamine) (1), [Ni(2-amnt)(3,4-daba)] (3,4-daba = 3, 4-diamino benzoic acid) (2) and [Ni(2-amnt)(dmnt)] (dmnt = diaminomaleonitrile) (3), were synthesized and characterized. Complexes 1–3 are active homogeneous proton reduction electrocatalysts in dimethylformamide with trifluoroacetic acid as a proton source. All the three complexes are tested in light-driven hydrogen evolution reaction, indicating different catalytic efficiencies. Thus, although complex 3 indicates no catalytic action, both complexes 1 and 2 catalyze H₂ evolution in water-dimethylformamide solutions using fluorescein (Fl) as a photosensitizer. Complex 2 acts as a homogeneous catalyst reached 834 turnovers (TON); whereas 1, despite being active in hydrogen evolution reaction (HER), decomposes to form nanomaterials. DFT calculations combined with electrochemical and spectroscopic data were employed to investigate the catalytic mechanism for H₂ formation as well as to unravel the key factors that influence the relative catalytic efficiencies. The proposed catalytic pathway involves ligand-based reduction and protonation steps followed by the formation of a nickel-hydride intermediate that reacts with a solution proton to generate H₂ via a very low energy transition state.     

Quality of hemodialysis water in a resource‐poor country: The Nigerian example

Hemodialysis (HD) patients are exposed to large volumes of water, separated from patients' blood by semipermeable membrane of dialyzers. Chemical contaminants in poorly treated water impact negatively on quality of life of these patients. This survey was carried out to assess the HD water quality in Lagos, Nigeria. Ten milliliters of feed and treated water from all six HD centers in Lagos were tested for aluminum, copper, zinc, magnesium, calcium using atomic absorption spectrometry; sodium and potassium were tested using flame photometry, fluoride with molecular photoluminescence method; sulfate using turbidimetry, nitrates measured by cadmium column reduction method, chloramines and free chlorine were measured using N, N‐diethyl‐1‐P‐phenylenediamine colorimetric method. Information on sources of feed water, frequency of testing of HD water, methods of water treatment, type of water purification system and maintenance was also obtained. All centers used borehole as main source of water supply. None of the centers met Association for the Advancement of Medical Instrumentation (AAMI) guidelines for most chemical contaminants. Only chlorine (0.48 ± 0.07 mg/L) and potassium (3.9 ± 0.95 mg/L) levels met AAMI standards after treatment. Mean levels of chemical contaminants in treated water were as follows: aluminum 0.04 ± 0.01 mg/L, zinc 0.27 ± 0.08 mg/L, chloramines 0.16 ± 0.03 mg/L, fluoride 1.83 ± 0.40 mg/L, sulfate 117 ± 86.1 mg/L which were mildly elevated; calcium 126.00 ± 22.7 mg/L, sodium 179 ± 25.6 mg/L, and nitrate 70.5 ± 50.8 mg/L, which were markedly elevated; and magnesium 8.3 ± 3.38 mg/L, which was moderately elevated above AAMI recommended levels. HD water quality is poor in our environment. Concerted efforts are required to ensure good quality water for HD.     

The influence of organization of LbL films containing a silsesquioxane polymer on the electrochemical response of dopamine

This paper describes the construction, evaluation, and application of an electrochemical sensor for the determination of dopamine (DA) in the presence of ascorbic acid (AA) and uric acid (UA). Satisfactory results were achieved for the simultaneous determination of DA and UA, it was verified that it is possible to detect AA in the presence of DA, but high concentrations of AA interfere in detection of DA. The sensor was constructed using the layer-by-layer (LbL) technique with the modification of the surface of indium tin oxide coated glass (ITO) substrate with nanostructured films comprising a 3-n-propylpyridinium silsesquioxane polymer (SiPy⁺Cl^?) and nickel(II) tetrasulfophthalocyanine (NiTsPc). Using the square wave voltammetry technique (SWV), the LbL modified electrodes produced at different pHs (pH 2 and 8) were used to determine DA in the presence UA, and the electrochemical responses of the electrodes were compared. It was observed that the electrodes with the highest concentration of monomeric species showed the highest current intensity and the lowest peak potential for the DA and UA analytes in analysis of DA and UA, individually and simultaneously, with peak potential separation of 460 mV versus Ag/AgCl. Applying SWV, a linear dynamic range of 10–99 μmol L^?1 and 100–900 μmol L^?1 with detection limit of 16.8 μmol L^?1 and 58.3 μmol L^?1 was obtained for DA and UA, respectively. The method has good selectivity and sensitivity, and it was successfully applied to the simultaneous determination of DA and UA in spiked human urine sample.     

ADAPTIVE AND STOCHASTIC FINITE ELEMENT ANALYSIS IN DRYING

ABSTRACT

The focus of this paper is on the use of new advances in the finite element method to model and analyze drying problems, with emphasis on biological, food and grain materials. It presents the current status of the use of numerical analysis for such process, and emphasizes the need and advantages of incorporating adaptive and stochastic strategies into the finite element analysts. The existing literature on the application of the adaptive and stochastic finite elements is reviewed in conjunction with the relevant advances in this area. A new perturbation-based stochastic methodology far nonlinear and transient drying problems is formulated and presented in detail. The specific application of this new methodology to drying is under development. In conclusion, tracks for future research in this field are proposed.     

Accident sequence precursor analysis: level 2/3 model development

The US Nuclear Regulatory Commission’s Accident Sequence Precursor (ASP) program currently uses simple level 1 models to assess the conditional core damage probability for operational events occurring in commercial nuclear power plants (NPP). Not all accident sequences leading to core damage will result in the same radiological consequences. Therefore, it is necessary to develop simple level 2/3 models that can be used to analyze the response of the NPP containment structure in the context of a core damage accident, estimate the magnitude of the resulting radioactive releases to the environment, and calculate the consequences associated with these releases. This level 2/3 model development work was initiated in 1995, and several prototype models have been completed. Two versions of these prototype level 2/3 models have been developed. Simple level 2/3 models have been linked to the simple level 1 models to provide risk perspectives for operational events. Additionally, very complex and detailed models have been developed that take provide much greater flexibility in accommodating a much wider range of level 1 core damage accident sequences. These detailed models also make possible assessments that are integrated with the level 1 model, on the importance of different severe accident phenomena and containment performance characteristics. This paper describes the development and capabilities of these level 2/3 ASP models, and the linkage to the level 1 models.     

The use of silicon nitride in buried contact solar cells

Silicon nitride offers many potential benefits to the family of buried contact fabrication sequences including improved design flexibility and efficiency. The main device structures of the buried contact family comprise the standard buried contact, the simplified buried contact and the double-sided buried contact cells. The physical properties of silicon nitride allow it to be used for surface passivation, as an anti-reflection coating, as a diffusion source material and as a masking dielectric. The use of silicon nitride in each buried contact fabrication sequence is described in this work.     

ADAPTIVE AND STOCHASTIC FINITE ELEMENT ANALYSIS IN DRYING

The focus of this paper is on the use of new advances in the finite element method to model and analyze drying problems, with emphasis on biological, food and grain materials. It presents the current status of the use of numerical analysis for such process, and emphasizes the need and advantages of incorporating adaptive and stochastic strategies into the finite element analysts. The existing literature on the application of the adaptive and stochastic finite elements is reviewed in conjunction with the relevant advances in this area. A new perturbation-based stochastic methodology far nonlinear and transient drying problems is formulated and presented in detail. The specific application of this new methodology to drying is under development. In conclusion, tracks for future research in this field are proposed.     

Effects of neonatal (Day 10) olfactory bulb lesions on social behavior of female golden hamsters (Mesocricetus auratus).

Found that, after neonatal (Day 10) bilateral olfactory bulbectomy (BOB; n = 16), adult female golden hamsters' scent marking and defense behavior to males was reduced relative to sham (n = 13) or neocortically lesioned (n = 11) littermate controls. The BOB aggressive and sexual behavior appeared grossly normal-15 were successfully mated, but 5 destroyed their litters. After mating, controls became more aggressive but BOB aggression decreased and had disappeared by the 2nd wk. of pregnancy. All groups ceased scent marking after mating, but controls returned to premating levels during lactation. The BOB Ss showed no scent marking, defense, or aggression throughout lactation. Unilateral olfactory bulbectomy of 6 Ss also eliminated normal social behavior during lactation, suggesting that not all the behavioral effects of olfactory damage can be attributed to anosmia. (29 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lysophosphatidic Acid Is a Proinflammatory Stimulus of Renal Tubular Epithelial Cells

Chronic kidney disease (CKD) refers to a spectrum of diseases defined by renal fibrosis, permanent alterations in kidney structure, and low glomerular-filtration rate. Prolonged epithelial-tubular damage involves a series of changes that eventually lead to CKD, highlighting the importance of tubular epithelial cells in this process. Lysophosphatidic acid (LPA) is a bioactive lipid that signals mainly through its six cognate LPA receptors and is implicated in several chronic inflammatory pathological conditions. In this report, we have stimulated human proximal tubular epithelial cells (HKC-8) with LPA and 175 other possibly pathological stimuli, and simultaneously detected the levels of 27 intracellular phosphoproteins and 32 extracellular secreted molecules with multiplex ELISA. This quantification revealed a large amount of information concerning the signaling and the physiology of HKC-8 cells that can be extrapolated to other proximal tubular epithelial cells. LPA responses clustered with pro-inflammatory stimuli such as TNF and IL-1, promoting the phosphorylation of important inflammatory signaling hubs, including CREB1, ERK1, JUN, IκΒα, and MEK1, as well as the secretion of inflammatory factors of clinical relevance, including CCL2, CCL3, CXCL10, ICAM1, IL-6, and IL-8, most of them shown for the first time in proximal tubular epithelial cells. The identified LPA-induced signal-transduction pathways, which were pharmacologically validated, and the secretion of the inflammatory factors offer novel insights into the possible role of LPA in CKD pathogenesis.