Characterization of a perfect sinusoidal grating profile using an artificial neural network for plasmonic-based sensors.

In this paper, we present a system intended to detect a targeted perfect sinusoidal profile of a diffraction grating during its manufactured process. Indeed, the sinusoidal nature of the periodic structure is essential to ensure optimal efficiency of specific applications as plasmonic sensors (surface plasmon resonance -based sensors). A neural network is implemented to characterize the geometrical shape of the structure under testing at the end of the laser interference lithography process.

Hypervalent Phosphorus(V) Porphyrins with -Methoxyphenyl Substituents: Significance of the Number and Position of Methoxy Groups in Promoting Intramolecular Charge Transfer.

To study the photophysical and redox properties as a function of -aryl units, a series of hypervalent phosphorus(V) porphyrins, PP(OMe)·PF, PMP(OMe)·PF, PDMP(OMe)·PF, P345TMP(OMe)·PF, and P246TMP(OMe)·PF, with phenyl (P), 4-methoxyphenyl (MP), 3,5-dimethoxyphenyl (DMP), 3,4,5-trimethoxyphenyl (345TMP), and 2,4,6-trimethoxyphenyl (246TMP) units, respectively, have been synthesized. The P(+5) in the cavity makes the porphyrin ring electron-poor, whereas the methoxy groups make the -phenyl rings electron-rich. The presence of electron-rich and electron-poor portions within the porphyrin molecule promoted an intramolecular charge transfer (ICT).

Antimony(+5) ion induced tunable intramolecular charge transfer in hypervalent antimony(V) porphyrins.

The +5 oxidation state of antimony induced push-pull style intramolecular charge transfer in an elegantly designed axial dimethoxyantimony(V) porphyrin series: SbP(OMe)·PF, SbMP(OMe)·PF, SbDMP(OMe)·PF, SbTMP(OMe)·PF with phenyl (P), 4-methoxyphenyl (MP), 3,5-dimethoxyphenyl (DMP), and 3,4,5-trimethoxyphenyl (TMP) units, respectively, in its positions. The Sb(+5) made the porphyrin ring electron-poor, whereas the methoxy groups on the phenyl unit produced electron-rich sites within the molecule. The presence of electron-poor and electron-rich parts in the same molecule resulted in a push-pull type intramolecular charge transfer (ICT).

Rational Design and Synthesis of OEP and TPP Centered Phosphorus(V) Porphyrin-Naphthalene Conjugates: Triplet Formation via Rapid Charge Recombination.

Six new "axial-bonding" type "phosphorus(V) porphyrin-naphthalene" conjugates have been prepared consisting of octaethylporphyrinatophosphorus(V) (POEP)/tetraphenylporphyrinatophosphorus(V) (PTPP) and naphthalene (NP). The distance between the porphyrin and NP was systematically varied using polyether bridges. The unique structural topology of the octaethylporphyrinatophosphorus(V) (POEP) and tetraphenylporphyrinatophosphorus(V) (PTPP) enabled construction of mono- and disubstituted phosphorus(V) porphyrin-naphthalene conjugates, respectively.

Experimental identification of a grating profile using neural network classifiers in optical scatterometry.

In this paper, we develop a new technique, to the best of our knowledge, of grating characterization based on two separate steps. First, an artificial neural network (ANN) is implemented in a classifier mode to identify the shape of the geometrical profile from a measured optical signature. Then, a second ANN is used in a regression mode to determine the geometrical parameters corresponding to the selected geometrical model.

A charge transfer state induced by strong exciton coupling in a cofacial μ-oxo-bridged porphyrin heterodimer.

Photosensitizers with high energy, long lasting charge-transfer states are important components in systems designed for solar energy conversion by multistep electron transfer. Here, we show that in a push-pull type, μ-oxo-bridged porphyrin heterodimer composed of octaethylporphyrinatoaluminum(iii) and octaethylporphyrinatophosphorus(v), the strong excitonic coupling between the porphyrins and the different electron withdrawing abilities of Al(iii) and P(v) promote the formation of a high energy CT state. Using, an array of optical and magnetic resonance spectroscopic methods along with theoretical calculations, we demonstrate photodynamics of the heterodimer that involves the initial formation of a singlet CT which relaxes to a triplet CT state with a lifetime of ∼130 ps.

Reconstruction of a complex profile shape by weighting basic characterization results for nanometrology.

Scatterometry has become an essential method of characterization during the fabrication process of nanostructures. This nondestructive technique based on diffracted light analysis is composed of two steps: the measurement of the optical signatures and the treatment to reconstruct the profile of the periodic structure. The artificial neural network has proved its effectiveness in solving the inverse scattering problem.

Surface anchored self-assembled reaction centre mimics as photoanodes consisting of a secondary electron donor, aluminium(iii) porphyrin and TiO semiconductor.

A series of vertically assembled photoanodes, consisting of 5,10,15,20-tetrakis(3,4,5-trifluorophenyl)aluminum(iii) porphyrin (AlPorF), a pyridine appended electron donor (PTZ-Py, PTZ = phenothiazine; TTF-Py, TTF = tetrathiafulvalene), and semiconductor TiO, have been fabricated by exploiting the unique axial properties of AlPorF. The new photoanodes were characterized by steady-state and transient spectroscopic techniques. Transient-absorption studies show that in the absence of a donor, both the photoanodes (AlPorF-TiO and AlPorF-Ph-TiO) exhibit electron injection from AlPorF into the conduction band of TiO and the injection efficiencies are strongly dependent on the linker.

Risks of ingestion of aflatoxin-contaminated groundnuts in Benin: scale measurements, beliefs, and socioeconomic factors.

This study evaluates farmers' beliefs and perceived risks of aflatoxin (AF) on the consumption, production, and marketing of groundnuts. A survey was conducted with 181 farmers in Benin to assess their beliefs of AF effects on the marketing of groundnuts, and finally human and animal health. Awareness and action factors were also evaluated.

HIV/AIDS-related stigma in Kumasi, Ghana.

Objective: To assess HIV/AIDS-related stigma and discrimination of people living with HIV/AIDS (PLWHA) in Kumasi, Ghana.

Methods: A cross-sectional survey of 104 adults from the four sub-districts in Kumasi was conducted.

Results: Four stigma constructs, employment-based discrimination, screening and identification of HIV positive people, revelation of HIV status and social contact stigma were determined based on reliability measures from responses to the questionnaire.

Sociocultural correlates of HIV/AIDS-related stigma in rural Jamaica.

Unlabelled: BACKGROUND; AIDS-related stigma is one of the biggest obstacles in the fight to prevent HIV transmission. Since stigma deters people from seeking treatment or getting tested for HIV, determining the factors that underpin AIDS-related stigmatization may be key to finding new ways to improve care and support for people living with HIV/AIDS (PLWHA) and to reduce new infections.

Setting: The town of Lucea and surrounding communities in the parish of Hanover, Jamaica.

The economics of adoption and management of alley cropping in Haiti.

The Haitian people are facing serious problems of environmental degradation that threaten the economic livelihoods of many resource-poor farmers. Structures to retard the process of soil loss have been adopted reluctantly and, even when adopted, the management and maintenance have been less than desirable. We evaluate the factors that influence the adoption and management of alley cropping in Haiti.

The exonuclease ISG20 mainly localizes in the nucleolus and the Cajal (Coiled) bodies and is associated with nuclear SMN protein-containing complexes.

We have previously shown that ISG20, an interferon (IFN)-induced gene, encodes a 3' to 5' exoribonuclease member of the DEDD superfamily of exonucleases. ISG20 specifically degrades single-stranded RNA. In this report, using immunofluorescence analysis, we demonstrate that in addition to a diffuse cytoplasmic and nucleoplasmic localization, the endogenous ISG20 protein was present in the nucleus both in the nucleolus and in the Cajal bodies (CBs).

Evidence for IRF-1-dependent gene expression deficiency in interferon unresponsive HepG2 cells.

Induction of the antiproliferative and antiviral state by IFNs (type I and II) is dramatically impaired in HepG2 cells. We show here that RNase L, IDO, GBP-2 and iNOS genes normally expressed as a secondary response to IFN are no longer inducible in HepG2 cells, while induction of primary response genes (IRF-1, PKR, p48-ISGF3gamma, 2-5AS, 6-16 and p56-(trp)tRNA) are unaffected. On the basis of previous data implicating transcription factor IRF-1 in the induction of some IFN-induced genes, we tested the effects of transfecting an IRF-1 oligonucleotide antisense in HeLa cells and found specifically impaired IFN induction of secondary response genes (RNase L, IDO and GBP-2).

Cardiac atrial natriuretic peptide (ANP) in rat dams and fetuses developed in space (NIH-R1 and NIH-R2 experiments).

NIH-R1 and R2 missions, conducted by NASA, allowed us to study the effects of the microgravitational environment 1) on cardiac ANP in pregnant rats, spaceflown for 11 days and dissected after a 2-day readaptation to Earth's gravity, after natural delivery, and 2) on maturation of cardiac ANP system in rat fetuses developed for 11 days in space and dissected on the day of landing, 2 days before birth. Immunocytochemical and electron microscopy analyses showed a typical formation of ANP-containing granules in atrial myocytes, in both dams and fetuses. Using competitive RT-PCR and radioimmunoassays, we observed that, after 2 days of readaptation to Earth's gravity, cardiac ANP biosynthesis of rat dams flown in space was increased by about twice, when compared to Synchronous and Vivarium Control rats.

Localization of a molecular form of interferon-regulated RNase L in the cytoskeleton.

RNase L (also termed 2-5A-dependent RNase) is a crucial enzyme involved in the molecular mechanism of interferon (IFN) action. Activated by 2',5'-oligoadenylate oligomers (2-5A), this enzyme controls the regulation of RNA stability in IFN-treated or virus-infected mammalian cells. Knowledge of RNase location within cells may provide additional information about its function.

Lack of 2',5'-oligoadenylate-dependent RNase expression in the human hepatoma cell line HepG2.

2',5'-adenylate oligonucleotide (2-5A)-dependent RNase and 2-5A-synthetase are two enzymes of the 2-5A system strongly implicated in the basal control of RNA decay of both interferon-treated and untreated cells. RNase is activated by a 2-5A produced by 2-5A-synthetase, both enzymes being overexpressed by type I-interferon (alpha/beta). We described here for the first time a cell line completely deficient in RNase and its mRNA, while p69 2-5A-synthetase was normally interferon alpha/beta-induced.

Upregulation of a myristylated 74-kDa protein by interferon treatment of Daudi cells.

Labeling of unstimulated human Daudi B lymphoblastoid cells with exogenously added [3H]myristate resulted in acylation of a broad spectrum of different proteins, most of which are currently unknown. Among this array of labeled proteins, a unique 74-kDa acylated protein was induced in interferon (IFN)-treated cells. In the present study, we defined the myristylation kinetics of this protein and examined the subcellular distribution before and after activation with IFN-alpha/beta.

Affinity purification and characterization of (2'-5')oligo(adenylate)-dependent RNase from mouse spleen.

Murine (2'-5')An-dependent RNase, a key enzyme of the interferon system, was purified from mouse spleen by affinity chromatography to immobilized (2'-5')An. Since the ribonuclease has high affinity to (2'-5')An, optimal non-denaturing conditions were obtained to disrupt the (2'-5')An-nuclease complex. Low-pH buffers in the presence of 0.

Cardiac and plasma atrial natriuretic peptide after 9-day hindlimb suspension in rats.

To determine atrial natriuretic peptide (ANP) adaptation to simulated weightlessness, immunoreactive plasma (ir-NH2- and ir-COOH-terminals) and atrial (ir-COOH-terminal) ANP levels, atrial mRNA expression, immunoreactive cardiocyte ANP levels (ir-NH2- and ir-COOH-terminals), and ultrastructural observations of granules in atrial cardiocytes were assessed in male Wistar rats after a 9-day hindlimb suspension. Plasma ir-NH2- and ir-COOH-terminal ANP concentrations decreased by 17 (P < 0.05) and 37% (P < 0.

2',5'-Oligoadenylate-dependent RNAse located in nuclei: biochemical characterization and subcellular distribution of the nuclease in human and murine cells.

A cellular fractionation procedure allowed the rapid preparation of membraneless nuclei which contained a 2',5'-oligoadenylate (2-5A)-binding activity which was not due to cytoplasmic contaminants. Purified nuclei prepared from human lymphocytic leukaemia cells and mouse fibroblasts were found to contain 20-22% of the total cellular enzyme. In contrast with the cytoplasmic enzyme which was only present in a 2-5A-free form, 75% of the 2-5A-binding activity was found in the nuclei after a denaturing-renaturing procedure as the 2-5A-binding site was masked.

Affinity blotting assay for 2-5A-dependent RNase.

The intracellular effectors known as 2-5A (ppp-(A2'p)nA) regulate the cleavage of single-stranded RNA by activating a latent endoribonuclease (2-5A-dependent RNase or RNase L). Accordingly this enzyme may exist in either an inactive form, free of 2-5A, or an active, 2-5A-bound form. Previously, a radiobinding assay for 2-5A-dependent RNase was developed that measured the amount of labeled ppp(A2'p)2A3'-[32P]Cp, a derivative of ppp(A2'p)nA, that bound the inactive enzyme form.

Photochemical crosslinking in oligonucleotide-protein complexes between a bromine-substituted 2-5A analog and 2-5A-dependent RNase by ultraviolet lamp or laser.

2',5'-oligoadenylates known as 2-5A [px(A2'p)nA; chi = 2 or 3, n greater than or equal to 2] are produced in interferon-treated cells in response to double-stranded RNA. 2-5A binds with high affinity to a 2-5A-dependent RNase resulting in the cleavage of single-stranded RNA. An efficient, rapid, and extremely sensitive photoaffinity labeling method was developed to facilitate detection of 2-5A-dependent RNase.

Characterization of two murine (2'-5')(A)n-dependent endonucleases of different molecular mass.

RNase L is considered as the major if not unique target of (2'-5')(A)n and therefore as an important intracellular mediator of interferon action. It behaves as an 185-kDa species in various cell extracts when analyzed by gel filtration. SDS/PAGE analysis of the polypeptides covalently labelled with a (2'-5')(A)4-3'-[32P]pCp probe reveals a single 80-kDa species, thus attesting a multimeric form of the 185-kDa protein.