Femtomolar detection of prostate-specific antigen: an immunoassay based on surface-enhanced Raman scattering and immunogold labels

A novel reagent for low-level detection in immunoadsorbent assays is described. The reagent consists of gold nanoparticles modified to integrate bioselective species (e.g., antibodies) with molecular labels for the generation of intense, biolyte-selective surface-enhanced Raman scattering (SERS) responses in immunoassays and other bioanalytical applications. The reagent is constructed by coating gold nanoparticles (30 nm) with a monolayer of an intrinsically strong Raman scatterer. These monolayer-level labels are bifunctional by design and contain disulfides for chemisorption to the nanoparticle surface and succinimides for coupling to the bioselective species. There are two important elements in this label design; it both minimizes the separation between label and particle surface and maximizes the number of labels on each particle. This approach to labeling also exploits several other advantages of SERS-based labels: narrow spectral bandwidth, resistance to photobleaching and quenching, and long-wavelength excitation of multiple labels with a single excitation source. The strengths of this strategy are demonstrated in the detection of free prostate-specific antigen (PSA) using a sandwich assay format based on monoclonal antibodies. Detection limits of approximately 1 pg/mL in human serum and approximately 4 pg/mL in bovine serum albumin have been achieved with a spectrometer readout time of 60 s. The extension of the method to multianalyte assays (e.g., the simultaneous determination of the many complexed forms of PSA) is discussed.     

Simulation of dye solar cells: through and beyond one dimension

In this work we present a Computer Aided Design (CAD) software, called TiberCAD, to simulate Dye Sensitized Solar Cells (DSC). DSCs are particularly interesting devices due to their high efficiency (more than 11% on small area and 8% on large area) and long stability. Since their first development, much progress has been made in terms of efficiency, stability, lifespan and engineering of the device. However, the field of DSCs still lacks a complete model able to simulate the entire device over a general domain including all its components. In our model a drift-diffusion set of equations for the different charge carriers coupled to Poisson equation has been implemented within finite element method. The model takes into account also trap assisted transport for electrons in the mesoporous titanium dioxide with a phenomenological model derived from multi-trapping model.     

Neuroticism's importance in understanding the daily life correlates of heart rate variability.

Individual differences in high-frequency heart rate variability (HRV) have been conceptualized in terms of a greater capacity to self-regulate problematic outcomes, but have also been conceptualized in terms of greater moment-to-moment flexibility. From a self-regulation perspective, higher HRV should be inversely correlated with trait neuroticism and problematic daily outcomes. From a flexibility perspective, high HRV should result in more state-like functioning—that is, functioning that is more contextual and less trait-like in nature. In the latter case, HRV and trait neuroticism may interact to predict problematic outcomes such that neuroticism should be a less consequential predictor at higher levels of HRV. The flexibility perspective was systematically supported in a daily experience-sampling protocol. Implications focus on theories of neuroticism and HRV. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Modeling of Dye sensitized solar cells using a finite element method

In this paper we present an electrical model to simulate a Dye sensitized Solar Cell (DSC) based on a Finite Element Method as an extension of the TiberCAD code. The CAD allows to calculate steady-state properties and ideal IV characteristic of the cell using 1, 2 and 3D meshes for the device. We describe the model and its prerogatives, explaining the code-related problems and the implementation of the model. We show a comparison with a measured IV curve, shading light on revealing the role of different parameters involved in the physics of conversion of light. Finally, an application to an experimental set-up, the Incident Photon to Current Efficiency, is presented, estimating the Collection Efficiency spectrum for a standard DSC and the collection efficiency spectrum for a standard DSC.     

Cerebral cystercosis. 3. cases observed in the Paris area in immigrant workers

The three cases described involve two Portugese patients and a Spaniard working in the Paris are who had presented with epilepsy, being focal in two. Diagnosis was made in two cases as a result of the existence of muscular and sub-cutaneous calcifications; in one case because of eosinophilia of the cerebro-spinal fluid. The clinical and therapeutic features of cerebral cysticercosis are recalled briefly in connection with these cases.     

Hepatocellular carcinoma in mixed cryoglobulinemia patients

Rosacea is an uncommon disease of the eye and facial skin. Ocular rosacea is often undiagnosed by the ophthalmologist especially when skin manifestations are not evident yet. Early diagnosis and treatment is important to decrease morbidity of this potentially blinding disease. A case of ocular rosacea in a 14-year-old Chinese girl is reported. Our patient presented with chronic non-specific keratoconjunctivitis. Only much later did the characteristic corneal and facial skin lesions appear. She responded to guttae prednisolone, oral and guttae tetracycline. This case illustrates the difficulty of early diagnosis when ocular manifestations precede those of the skin. We believe this is the first case of ocular rosacea reported in Singapore.     

Refractory ascites: definition, pathogenesis and treatment

Refractory ascites, that is ascites which cannot be mobilized by low sodium diet and maximal doses of diuretics (up to 400 mg spironolactone or potassium canrenoate and 160 mg furosemide per day), occurs in 5% of cirrhotic patients with ascites. The development of refractory ascites is mainly related to the progression of arterial vasodilation-mediated vascular underfilling and to the imbalance between reduced synthesis of renal vasodilating factors (especially renal prostaglandins) and extreme activation of vasoconstricting systems. Further features include increased sodium reabsorption in the proximal tubule and altered pharmacokinetics and pharmacodynamics of diuretics. In patients with impaired renal function (as is the case for most patients with refractory ascites), the marked reduction of renal perfusion and glomerular filtration rate, with the consequent decrease of filtered sodium load, becomes the main pathogenetic factor. The principal therapeutic options for refractory ascites include repeated paracentesis and implantation of the LeVeen shunt. Paracentesis is a rapid and safe procedure to remove ascites, but it does not correct sodium retention. Ascites recurrence, therefore, may occur after a brief interval. The LeVeen shunt allows for better long-term control of ascites, but severe complications may supervene, and shunt occlusion is common. Neither therapeutic procedure improves survival. Different experimental therapeutic procedures have been proposed. Administration of ornipressin corrects hyperdynamic circulation and improves renal function. Thromboxane synthase inhibitors, by reducing renal synthesis of thromboxane A2, potentiate the diuretic and natriuretic response to furosemide. More invasive procedures, including portosystemic shunt and transjugular intrahepatic stent, are rarely used in the treatment of refractory ascites.(ABSTRACT TRUNCATED AT 250 WORDS)