Quasi-parabolic pulses in a coherent nonlinear optical amplifier

We show that, in a coherent two-level optical amplifier with Kerr nonlinearity and linear loss, any weak seed pulse evolves into a fixed powerful linearly chirped pulse with quasi-parabolic shape. This process is associated with a transition from the incoherent into the coherent amplification regime, thus enabling in practice the generation of pulses with a spectrum wider than the linear gain bandwidth

Peptide Fingerprinting of Alzheimer's Disease in Cerebrospinal Fluid: Identification and Prospective Evaluation of New Synaptic Biomarkers

<p><b>Background:</b> Today, dementias are diagnosed late in the course of disease. Future treatments have to start earlier in the disease process to avoid disability requiring new diagnostic tools. The objective of this study is to develop a new method for the differential diagnosis and identification of new biomarkers of Alzheimer's disease (AD) using capillary-electrophoresis coupled to mass-spectrometry (CE-MS) and to assess the potential of early diagnosis of AD.</p> <p><b>Methods and Findings:</b> Cerebrospinal fluid (CSF) of 159 out-patients of a memory-clinic at a University Hospital suffering from neurodegenerative disorders and 17 cognitively-healthy controls was used to create differential peptide pattern for dementias and prospective blinded-comparison of sensitivity and specificity for AD diagnosis against the Criterion standard in a naturalistic prospective sample of patients. Sensitivity and specificity of the new method compared to standard diagnostic procedures and identification of new putative biomarkers for AD was the main outcome measure. CE-MS was used to reliably detect 1104 low-molecular-weight peptides in CSF. Training-sets of patients with clinically secured sporadic Alzheimer's disease, frontotemporal dementia, and cognitively healthy controls allowed establishing discriminative biomarker pattern for diagnosis of AD. This pattern was already detectable in patients with mild cognitive impairment (MCI). The AD-pattern was tested in a prospective sample of patients (n = 100) and AD was diagnosed with a sensitivity of 87% and a specificity of 83%. Using CSF measurements of beta-amyloid1-42, total-tau, and phospho(181)-tau, AD-diagnosis had a sensitivity of 88% and a specificity of 67% in the same sample. Sequence analysis of the discriminating biomarkers identified fragments of synaptic proteins like proSAAS, apolipoprotein J, neurosecretory protein VGF, phospholemman, and chromogranin A.</p> <p><b>Conclusions:</b> The method may allow early differential diagnosis of various dementias using specific peptide fingerprints and identification of incipient AD in patients suffering from MCI. Identified biomarkers facilitate face validity for the use in AD diagnosis.</p&gt

Quantification of silver nanoparticle uptake and distribution within individual human macrophages by FIB/SEM slice and view

Background: Quantification of nanoparticle (NP) uptake in cells or tissues is very important for safety assessment. Often, electron microscopy based approaches are used for this purpose, which allow imaging at very high resolution. However, precise quantification of NP numbers in cells and tissues remains challenging. The aim of this study was to present a novel approach, that combines precise quantification of NPs in individual cells together with high resolution imaging of their intracellular distribution based on focused ion beam/ scanning electron microscopy (FIB/SEM) slice and view approaches. Results: We quantified cellular uptake of 75 nm diameter citrate stabilized silver NPs (Ag 75 Cit) into an individual human macrophage derived from monocytic THP-1 cells using a FIB/SEM slice and view approach. Cells were treated with 10 μg/ml for 24 h. We investigated a single cell and found in total 3138 ± 722 silver NPs inside this cell. Most of the silver NPs were located in large agglomerates, only a few were found in clusters of fewer than five NPs. Furthermore, we cross-checked our results by using inductively coupled plasma mass spectrometry and could confirm the FIB/SEM results. Conclusions: Our approach based on FIB/SEM slice and view is currently the only one that allows the quantification of the absolute dose of silver NPs in individual cells and at the same time to assess their intracellular distribution at high resolution. We therefore propose to use FIB/SEM slice and view to systematically analyse the cellular uptake of various NPs as a function of size, concentration and incubation time

Activated particulate organic matter as a carbon source for denitrification in RAS.

Sustainable aquaculture supplies fish products to market to meet the increasing need of fish and fish products in human diet and industry. Recirculating aquaculture systems (RAS), in which there is constant reuse of water, offer an extremely resource-efficient way to produce fish. Yet, RAS also need a constant water filtration in order to achieve adequate water parameters and finally quality products. Efforts to increase the effectiveness of the nitrification biofilters and denitrification reactors and to decrease the amount of solid waste in form of fish faeces and waste diet from a RAS are central research topics in this field. The present study aimed: 1) To analyze how efficiently fish use the inputs to the RAS system and the content of what is lost (e.g. in fish faeces, foam, waste diet etc) within waste products from a RAS, 2) To determine if filtered particulate organic matter, otherwise disposed of as waste, may be used as carbon source in a recycling procedure within RAS and, 3) To evaluate the effectiveness of ozone-activated particulate organic matter when used by denitrification bacteria as external carbon source. An experiment was conducted in which individuals of European seabass Dicentrarchus labrax, kept in a RAS, were fed ad libitum with commercial feeds and the amount of solid waste (according to the feeds inputs) from the drum filter and the protein skimmer were determined, sampled before and after feeding and analyzed to examine their carbon, nitrogen and organic matter content (e.g. aminoacids, fatty acids) tested against the commercial feed used. Organic matter content was determined by gas chromatography and mass spectrometry. The sampled particulate organic matter from the drum filter was subsequently treated with ozone over various time intervals and its content analyzed to quantify simple carbon substrates feasible for use as carbon source by bacteria in the denitrification reactor. Ozone is commonly used for disinfection purpose and to clear the water from organic compounds responsible of the high turbidity of the water in RAS. It is as well toxic for living organism when higher levels leak to the system. The ozonized samples were tested against commercial carbon sources commonly used for RAS-denitrification at a laboratory scale with the aim of test it later on in a real system. The final objective is to evaluate the performance of denitrification reactors using ozone-activated particulate organic matter and to determine its influence on the growth performance of the studied species under these conditions as well as on the efficiency of the denitrification process. We expect to optimize RAS by recycling the particulate organic matter filtered out from the RAS and to find out the best ozone treatment time for obtaining an efficient denitrification and no collateral damage to the reared organisms or to the bacteria in denitrification reactors and nitrification biofilters. Preliminary results of this pilot study will be presented

Activity of a Novel bcl-2/bcl-xL-Bispecific Antisense Oligonucleotide Against Tumors of Diverse Histologic Origins

Background: Increased expression of the anti-apoptotic proteins Bcl-2 and Bcl-xL is involved in the development and progression of many tumors. We recently reported that the bcl-2/bcl-xL-bispecific antisense oligonucleotide 4625 induces apoptosis in lung carcinoma cells. To further assess the therapeutic potential of oligonucleotide 4625, we investigated its effect on a series of human tumor cell lines of diverse histologic origins in vitro and in vivo. Methods: Oligonucleotide 4625-mediated inhibition of bcl-2 and bcl-xL expression in vitro was measured in breast carcinoma cells with the use of reverse transcription-polymerase chain reaction (PCR), real-time PCR, and western blotting. Cytotoxicity was assessed in several different cell lines by measurement of tumor cell growth, propidium iodide uptake, and nuclear apoptosis. The in vivo activity of oligonucleotide 4625 was determined by the inhibition of growth of established tumor xenografts in nude mice, immunohistochemical staining of Bcl-2 and Bcl-x proteins in the tumors, and western blotting of tumor lysates. Apoptosis in tumor xenografts was detected with the use of in situ TUNEL (i.e., terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick end labeling) staining. All statistical tests are two-sided. Results: In breast carcinoma cells, oligonucleotide 4625 treatment reduced bcl-2 and bcl-xL messenger RNA levels in a dose-dependent manner. At 600 nM, oligonucleotide 4625 reduced Bcl-2 and Bcl-xL protein levels to 25% (95% confidence interval [CI] = 16% to 34%) and 20% (95% CI = 14% to 26%), respectively, of the levels in untreated cells and it decreased viability in all cell lines mainly by inducing apoptosis. In vivo, oligonucleotide 4625 statistically significantly inhibited the growth of breast and colorectal carcinoma xenografts by 51% (95% CI = 28% to 74%) and 59% (95% CI = 44% to 74%), respectively, relative to those treated with control oligonucleotide 4626; it also reduced Bcl-2 and Bcl-xL protein levels and induced tumor cell apoptosis. Conclusion: The bcl-2/bcl-xL-bispecific antisense oligonucleotide 4625 merits further study as a novel compound for cancer therap

An optimized split-ubiquitin cDNA-library screening system to identify novel interactors of the human Frizzled 1 receptor

The yeast split-ubiquitin system has previously been shown to be suitable to detect protein interactions of membrane proteins and of transcription factors in vivo. Therefore, this technology complements the classical split-transcription factor based yeast two-hybrid system (Y2H). Success or failure of the Y2H depends primarily on the ability to avoid false-negative and false-positive hits that become a limiting factor for the value of the system, especially in large scale proteomic analyses. We provide here a systematic assessment of parameters to help improving the quality of split-ubiquitin cDNA-library screenings. We experimentally defined the optimal 5-fluoroorotic acid (5-FOA) concentration as a key parameter to increase the reproducibility of interactions and, at the same time, to keep non-specific background growth low. Furthermore, we show that the efficacy of the 5-FOA selection is modulated by the plating density of the yeast clones. Moreover, a reporter-specific class of false-positive hits was identified, and a simple phenotypic assay for efficient de-selection was developed. We demonstrate the application of this improved system to identify novel interacting proteins of the human Frizzled 1 receptor. We identified several novel interactors with components of the Wnt-Frizzled signalling pathways and discuss their potential roles as direct mediators of Frizzled receptor signalling. The present work is the first example of a split-ubiquitin interaction screen using an in-situ expressed receptor of the serpentine class, emphasizing the suitability of the described improvements in the screening protocol