264 resultados para multiplexed
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This paper considers the problem of dedicated path-protection in wavelength-division multiplexed (WDM) mesh networks with waveband switching functionality under shared risk link group (SRLG) constraints. Two dedicated path protection schemes are proposed, namely the PBABL scheme and the MPABWL scheme. The PBABL scheme protects each working waveband-path through a backup waveband-path. The MPABWL scheme protects each working waveband-path by either a backup waveband-path or multiple backup lightpaths. Heuristic algorithms adopting random optimization technique are proposed for both the schemes. The performance of the two protection schemes is studied and compared. Simulation results show that both the heuristics can obtain optimum solutions and the MPABWL scheme leads to less switching and transmission costs than the PBABL scheme.
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Waveband switching (WBS) is an important technique to save switching and transmission cost in wavelength -division multiplexed (WDM) optical networks. A cost-efficient WBS scheme would enable network carriers to increase the network throughput (revenue) while achieving significant cost savings. We identify the critical factors that determine the WBS network throughput and switching cost and propose a novel intermediate waveband switching (IT-WBS) algorithm, called the minimizing-weighted-cost (MWC) algorithm. The MWC algorithm defines a cost for each candidate route of a call. By selecting the route with the smallest weighted cost, MWC balances between minimizing the call blocking probability and minimizing the network switching cost. Our simulations show that MWC outperforms other wavelength/waveband switching algorithms and can enhance the network throughput at a reduced cost.
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A wavelength-routed optical network consists of multi-wavelength crossconnect switches (XCSs) which are interconnected by optical fibers. Some (or all) crossconnects, referred to as nodes in this paper, are also attached to access stations where data from several end-users could be multiplexed onto a single wavelength division multiplexed (WDM) channel. An access station provides optical-to-electronic (O/E) conversion and wice wersa to interface the optical network with conventional electronic equipment. The access station, at an intermediate node, may also be used (as in this study) for signal regenerution on a lightpath. A new call is admitted into the network if a lightpath (a set of free wavelengths along a given route from source to destination) can be established between the call’s source and destination stations. Depending on the number of all-optical fragments in a single lightpath, three different approaches may be employed to operate such a network. These approaches are: transparency, opacity, and translucency (to be explained below). Our study concentrates on evaluating the relative merits of these three approaches in a sample network environment.
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Background: Balancing the subject composition of case and control groups to create homogenous ancestries between each group is essential for medical association studies. Methods: We explored the applicability of single-tube 34-plex ancestry informative markers (AIM) single nucleotide polymorphisms (SNPs) to estimate the African Component of Ancestry (ACA) to design a future case-control association study of a Brazilian urban sample. Results: One hundred eighty individuals (107 case group; 73 control group) self-described as white, brown-intermediate or black were selected. The proportions of the relative contribution of a variable number of ancestral population components were similar between case and control groups. Moreover, the case and control groups demonstrated similar distributions for ACA <0.25 and >0.50 categories. Notably a high number of outlier values (23 samples) were observed among individuals with ACA <0.25. These individuals presented a high probability of Native American and East Asian ancestral components; however, no individuals originally giving these self-described ancestries were observed in this study. Conclusions: The strategy proposed for the assessment of ancestry and adjustment of case and control groups for an association study is an important step for the proper construction of the study, particularly when subjects are taken from a complex urban population. This can be achieved using a straight forward multiplexed AIM-SNPs assay of highly discriminatory ancestry markers.
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The subject of this Ph.D. research thesis is the development and application of multiplexed analytical methods based on bioluminescent whole-cell biosensors. One of the main goals of analytical chemistry is multianalyte testing in which two or more analytes are measured simultaneously in a single assay. The advantages of multianalyte testing are work simplification, high throughput, and reduction in the overall cost per test. The availability of multiplexed portable analytical systems is of particular interest for on-field analysis of clinical, environmental or food samples as well as for the drug discovery process. To allow highly sensitive and selective analysis, these devices should combine biospecific molecular recognition with ultrasensitive detection systems. To address the current need for rapid, highly sensitive and inexpensive devices for obtaining more data from each sample,genetically engineered whole-cell biosensors as biospecific recognition element were combined with ultrasensitive bioluminescence detection techniques. Genetically engineered cell-based sensing systems were obtained by introducing into bacterial, yeast or mammalian cells a vector expressing a reporter protein whose expression is controlled by regulatory proteins and promoter sequences. The regulatory protein is able to recognize the presence of the analyte (e.g., compounds with hormone-like activity, heavy metals…) and to consequently activate the expression of the reporter protein that can be readily measured and directly related to the analyte bioavailable concentration in the sample. Bioluminescence represents the ideal detection principle for miniaturized analytical devices and multiplexed assays thanks to high detectability in small sample volumes allowing an accurate signal localization and quantification. In the first chapter of this dissertation is discussed the obtainment of improved bioluminescent proteins emitting at different wavelenghts, in term of increased thermostability, enhanced emission decay kinetic and spectral resolution. The second chapter is mainly focused on the use of these proteins in the development of whole-cell based assay with improved analytical performance. In particular since the main drawback of whole-cell biosensors is the high variability of their analyte specific response mainly caused by variations in cell viability due to aspecific effects of the sample’s matrix, an additional bioluminescent reporter has been introduced to correct the analytical response thus increasing the robustness of the bioassays. The feasibility of using a combination of two or more bioluminescent proteins for obtaining biosensors with internal signal correction or for the simultaneous detection of multiple analytes has been demonstrated by developing a dual reporter yeast based biosensor for androgenic activity measurement and a triple reporter mammalian cell-based biosensor for the simultaneous monitoring of two CYP450 enzymes activation, involved in cholesterol degradation, with the use of two spectrally resolved intracellular luciferases and a secreted luciferase as a control for cells viability. In the third chapter is presented the development of a portable multianalyte detection system. In order to develop a portable system that can be used also outside the laboratory environment even by non skilled personnel, cells have been immobilized into a new biocompatible and transparent polymeric matrix within a modified clear bottom black 384 -well microtiter plate to obtain a bioluminescent cell array. The cell array was placed in contact with a portable charge-coupled device (CCD) light sensor able to localize and quantify the luminescent signal produced by different bioluminescent whole-cell biosensors. This multiplexed biosensing platform containing whole-cell biosensors was successfully used to measure the overall toxicity of a given sample as well as to obtain dose response curves for heavy metals and to detect hormonal activity in clinical samples (PCT/IB2010/050625: “Portable device based on immobilized cells for the detection of analytes.” Michelini E, Roda A, Dolci LS, Mezzanotte L, Cevenini L , 2010). At the end of the dissertation some future development steps are also discussed in order to develop a point of care (POCT) device that combine portability, minimum sample pre-treatment and highly sensitive multiplexed assays in a short assay time. In this POCT perspective, field-flow fractionation (FFF) techniques, in particular gravitational variant (GrFFF) that exploit the earth gravitational field to structure the separation, have been investigated for cells fractionation, characterization and isolation. Thanks to the simplicity of its equipment, amenable to miniaturization, the GrFFF techniques appears to be particularly suited for its implementation in POCT devices and may be used as pre-analytical integrated module to be applied directly to drive target analytes of raw samples to the modules where biospecifc recognition reactions based on ultrasensitive bioluminescence detection occurs, providing an increase in overall analytical output.
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Le reti ottiche, grazie alla loro elevata capacità, hanno acquisito sempre maggiore importanza negli ultimi anni, sia per via del crescente volume di dati scambiati, legato soprattutto alla larga diffusione di Internet, sia per la necessità di comunicazioni in tempo reale. Dati i (relativamente) lunghi tempi di adattamento, questa tecnologia nativamente non è quella ottimale per il trasporto di un traffico a burst, tipico delle telecomunicazioni odierne. Le reti ibride cercano, quindi, di coniugare al meglio le potenzialità della commutazione ottica di circuito e della commutazione ottica a pacchetto. In questo lavoro, in particolare, ci si è concentrati su un'architettura di rete ibrida denominata 3LIHON (3-Level Integrated Hybrid Optical Network). Essa prevede tre distinti livelli di qualità di servizio (QoS) per soddisfare differenti necessità: - Guaranteed Service Type (GST): simile ad un servizio a commutazione di circuito, non ammette perdita di dati. - Statistically Multiplexed Real Time (SM/RT): simile ad un servizio a commutazione di pacchetto, garantisce ritardo nullo o molto basso all'interno della rete, permette un piccolo tasso di perdita di dati e ammette la contesa della banda. - Statistically Multiplexed Best Effort (SM/BE): simile ad un servizio a commutazione di pacchetto, non garantisce alcun ritardo tra i nodi ed ammette un basso tasso di perdita dei dati. In un nodo 3LIHON, il traffico SM/BE impossibile da servire, a causa ad es. dell'interruzione da parte di pacchetti aventi un livello di QoS più prioritario, viene irrimediabilmente perso. Questo implica anche lo spreco del tempo e delle risorse impiegati per trasmettere un pacchetto SM/BE fino alla sua interruzione. Nel presente lavoro si è cercato di limitare, per quanto possibile, questo comportamento sconveniente, adottando e comparando tre strategie, che hanno portato alla modifica del nodo 3LIHON standard ed alla nascita di tre sue varianti.
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Plasmonische Metallnanopartikel bündeln, verstärken und beeinflussen Licht auf nanoskopischer Ebene. Diese grundlegende Eigenschaft kommt von koheränten, kollektiven Schwingungen der Leitungsbandelektronen, die von einfallendem Licht resonant angeregt und lokalisierte Oberflächenplasmonenresonanz (LSPR) oder ‚Partikelplasmonen‘ genannt werden. Plasmonen in Metallnanopartikeln wurden bisher z.B. zur Erkennen von pathogenen Biomolekülen, bei der photothermischen Therapie und zur Verbesserung der Effizienz von Solarzellen verwendet. In dieser Arbeit werde ich meinen Fokus auf die Synthese und Funktionalisierung von Goldnanopartikeln zur Anwendung als Sensoren legen.rnrnKürzliche Verbesserungen in der nasschemischen Synthese haben zur Herstellung von Goldnanopartikel mit unterschiedlichen Formen und Größen geführt, die sich in ihren Sensoreigenschaften unterscheiden. Unter den unterschiedlichen Sensorgeometrien sind Goldnanostäbchen die bevorzugte Form zur Biomolekül-Sensorik durch LSPR. Nanostäbchen werden durch eine positiv geladene CTAB-Schicht stabilisiert, die Proteine bei neutralem pH-Wert anziehen kann. Die Adsorption und Desorption von Proteinen an der Nanopartikeloberfläche und damit die Bindungskinetiken von Proteinen kann auf Einzelmolekülebene erforscht werden. Ich zeige hier eine Studie mit hoher örtlicher und zeitlicher Auflösung um einzelne Bindungsereignisse von Fibronectin auf Goldnanostäbchen darzustellen.rnrnGoldnanostäbchen müssen mit spezifischen biologischen Erkennungselementen funktionalisiert werden um eine Analyterkennung oder Proteinwechselwirkung zu erreichen. Ich funktionalisiere Goldnanostäbchen mit kurzen DNA-Sequenzen (Aptamer-Sequenzen und NTA konjugierten Polihymidinen) und habe anhand diese unterschiedlich sensitiven Partikel eine Studie mit verschiedenen Analyten (oder Protein-Protein Wechselwirkungen) erfolgreich durchgeführt.rn rnPlasmonen von Nanopartikel-Clustern koppeln miteinander, was ihre Resonanzenergie ändert. Der kontrollierte Zusammenbau von Nanopartikeln zu Dimeren oder höher geordneten Strukturen wie ‚Core-Satellites‘ können dazu dienen ihre Sensitivität zu erhöhen. Diese Cluster bieten eine hohe Sensitivität auf Grund der Anwesenheit von plasmonischen Hotspots in der Lücke zwischen zwei Partikeln. Die Plasmonkopplung ist ein Phänomen, das abhängig vom Abstand zweier Partikel zueinander ist und bildet somit die Basis von sogenannten Plasmon-Linealen. Ich habe eine Strategie entwickelt um Dimere aus Hsp90 funktionalisierten Goldnanosphären zu bilden. Diese Technik wird nicht durch Ausbleichen oder das Blinken von Farbstoffen limitiert und ich zeige zum ersten Mal wie man dadurch dynamische Proteinkonformationen untersuchen kann.rn
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Glycan-binding antibodies form a significant subpopulation of both natural and acquired antibodies and play an important role in various immune processes. They are for example involved in innate immune responses, cancer, autoimmune diseases, and neurological disorders. In the present study, a microsphere-based flow-cytometric immunoassay (suspension array) was applied for multiplexed detection of glycan-binding antibodies in human serum. Several approaches for immobilization of glycoconjugates onto commercially available fluorescent microspheres were compared, and as the result, the design based on coupling of end-biotinylated glycopolymers has been selected. This method requires only minute amounts of glycans, similar to a printed glycan microarray. The resulting glyco-microspheres were used for detection of IgM and IgG antibodies directed against ABO blood group antigens. The possibility of multiplexing this assay was demonstrated with mixtures of microspheres modified with six different ABO related glycans. Multiplexed detection of anti-glycan IgM and IgG correlated well with singleplex assays (Pearson's correlation coefficient r = 0.95-0.99 for sera of different blood groups). The suspension array in singleplex format for A/B trisaccharide, H(di) and Le(x) microspheres corresponded well to the standard ELISA (r > 0.94). Therefore, the described method is promising for rapid, sensitive, and reproducible detection of anti-glycan antibodies in a multiplexed format.
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Over the last decade, translational science has come into the focus of academic medicine, and significant intellectual and financial efforts have been made to initiate a multitude of bench-to-bedside projects. The quest for suitable biomarkers that will significantly change clinical practice has become one of the biggest challenges in translational medicine. Quantitative measurement of proteins is a critical step in biomarker discovery. Assessing a large number of potential protein biomarkers in a statistically significant number of samples and controls still constitutes a major technical hurdle. Multiplexed analysis offers significant advantages regarding time, reagent cost, sample requirements and the amount of data that can be generated. The two contemporary approaches in multiplexed and quantitative biomarker validation, antibody-based immunoassays and MS-based multiple (or selected) reaction monitoring, are based on different assay principles and instrument requirements. Both approaches have their own advantages and disadvantages and therefore have complementary roles in the multi-staged biomarker verification and validation process. In this review, we discuss quantitative immunoassay and multiple reaction monitoring/selected reaction monitoring assay principles and development. We also discuss choosing an appropriate platform, judging the performance of assays, obtaining reliable, quantitative results for translational research and clinical applications in the biomarker field.
Levels and determinants of inflammatory biomarkers in a Swiss population-based sample (CoLaus study)
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Objective to assess the levels and determinants of interleukin (IL)-1β, IL-6, tumour necrosis factor (TNF)-α and C-reactive protein (CRP) in a healthy Caucasian population. Methods population sample of 2884 men and 3201 women aged 35 to 75. IL-1β, IL-6 and TNF-α were assessed by a multiplexed particle-based flow cytometric assay and CRP by an immunometric assay. Results Spearman rank correlations between duplicate cytokine measurements (N = 80) ranged between 0.89 and 0.96; intra-class correlation coefficients ranged between 0.94 and 0.97, indicating good reproducibility. Among the 6085 participants, 2289 (37.6%), 451 (7.4%) and 43 (0.7%) had IL-1β, IL-6 and TNF-α levels below detection limits, respectively. Median (interquartile range) for participants with detectable values were 1.17 (0.48–3.90) pg/ml for IL-1β; 1.47 (0.71–3.53) pg/ml for IL-6; 2.89 (1.82–4.53) pg/ml for TNF-α and 1.3 (0.6–2.7) ng/ml for CRP. On multivariate analysis, greater age was the only factor inversely associated with IL-1β levels. Male sex, increased BMI and smoking were associated with greater IL-6 levels, while no relationship was found for age and leisure-time PA. Male sex, greater age, increased BMI and current smoking were associated with greater TNF-α levels, while no relationship was found with leisure-time PA. CRP levels were positively related to age, BMI and smoking, and inversely to male sex and physical activity. Conclusion Population-based levels of several cytokines were established. Increased age and BMI, and to a lesser degree sex and smoking, significantly and differentially impact cytokine levels, while leisure-time physical activity has little effect.
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OBJECTIVE: The associations between inflammation, diabetes and insulin resistance remain controversial. Hence, we assessed the associations between diabetes, insulin resistance (using HOMA-IR) and metabolic syndrome with the inflammatory markers high sensitivity C-reactive protein (hs-CRP), interleukin-1beta (IL-1β), interleukin-6 (IL-6) and tumour necrosis factor-α (TNF-α). DESIGN: CROSS-SECTIONAL STUDY: PARTICIPANTS: 2884 MEN AND 3201 WOMEN AGED 35 TO 75: METHODS: CRP was assessed by immunoassay and cytokines by multiplexed flow cytometric assay. In a subgroup of 532 participants an oral glucose tolerance test was performed to screen for impaired glucose tolerance (IGT). RESULTS: IL-6, TNF-α and hs-CRP were significantly and positively correlated with fasting plasma glucose, insulin and HOMA-IR. Participants with diabetes had higher IL-6, TNF-α and hs-CRP levels than participants without diabetes; this difference persisted for hs-CRP after multivariate adjustment. Participants with metabolic syndrome had increased IL-6, TNF-α and hs-CRP levels; these differences persisted after multivariate adjustment. Participants in the highest quartile of HOMA-IR had increased IL-6, TNF-α and hs-CRP levels; these differences persisted for TNF-α and hs-CRP after multivariate adjustment. No association was found between IL-1β levels and all diabetes and insulin resistance markers studied. Finally, participants with IGT had higher hs-CRP levels than participants with a normal OGTT, but this difference disappeared after controlling for body mass index (BMI). CONCLUSION: subjects with diabetes, metabolic syndrome and increased insulin resistance present with increased levels of IL6, TNF-α and hs-CRP, while no association was found with IL-1β. The increased inflammatory state of subjects with IGT is partially explained by increased BMI. © 2012 Blackwell Publishing Ltd.
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Commercially available assays for the simultaneous detection of multiple inflammatory and cardiac markers in porcine blood samples are currently lacking. Therefore, this study was aimed at developing a bead-based, multiplexed flow cytometric assay to simultaneously detect porcine cytokines [interleukin (IL)-1β, IL-6, IL-10, and tumor necrosis factor alpha], chemokines (IL-8 and monocyte chemotactic protein 1), growth factors [basic fibroblast growth factor (bFGF), vascular endothelial growth factor, and platelet-derived growth factor-bb], and injury markers (cardiac troponin-I) as well as complement activation markers (C5a and sC5b-9). The method was based on the Luminex xMAP technology, resulting in the assembly of a 6- and 11-plex from the respective individual singleplex situation. The assay was evaluated for dynamic range, sensitivity, cross-reactivity, intra-assay and interassay variance, spike recovery, and correlation between multiplex and commercially available enzyme-linked immunosorbent assay as well as the respective singleplex. The limit of detection ranged from 2.5 to 30,000 pg/ml for all analytes (6- and 11-plex assays), except for soluble C5b-9 with a detection range of 2-10,000 ng/ml (11-plex). Typically, very low cross-reactivity (<3% and <1.4% by 11- and 6-plex, respectively) between analytes was found. Intra-assay variances ranged from 4.9 to 7.4% (6-plex) and 5.3 to 12.9% (11-plex). Interassay variances for cytokines were between 8.1 and 28.8% (6-plex) and 10.1 and 26.4% (11-plex). Correlation coefficients with singleplex assays for 6-plex as well as for 11-plex were high, ranging from 0.988 to 0.997 and 0.913 to 0.999, respectively. In this study, a bead-based porcine 11-plex and 6-plex assay with a good assay sensitivity, broad dynamic range, and low intra-assay variance and cross-reactivity was established. These assays therefore represent a new, useful tool for the analysis of samples generated from experiments with pigs.
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PURPOSE To explore differential methylation of HAAO, HOXD3, LGALS3, PITX2, RASSF1 and TDRD1 as a molecular tool to predict biochemical recurrence (BCR) in patients with high-risk prostate cancer (PCa). METHODS A multiplexed nested methylation-specific PCR was applied to quantify promoter methylation of the selected markers in five cell lines, 42 benign prostatic hyperplasia (BPH) and 71 high-risk PCa tumor samples. Uni- and multivariate Cox regression models were used to assess the importance of the methylation level in predicting BCR. RESULTS A PCa-specific methylation marker HAAO in combination with HOXD3 and a hypomethylation marker TDRD1 distinguished PCa samples (>90 % of tumor cells each) from BPH with a sensitivity of 0.99 and a specificity of 0.95. High methylation of PITX2, HOXD3 and RASSF1, as well as low methylation of TDRD1, appeared to be significantly associated with a higher risk for BCR (HR 3.96, 3.44, 2.80 and 2.85, correspondingly) after correcting for established risk factors. When DNA methylation was treated as a continuous variable, a two-gene model PITX2 × 0.020677 + HOXD3 × 0.0043132 proved to be the best predictor of BCR (HR 4.85) compared with the individual markers. This finding was confirmed in an independent set of 52 high-risk PCa tumor samples (HR 11.89). CONCLUSIONS Differential promoter methylation of HOXD3, PITX2, RASSF1 and TDRD1 emerges as an independent predictor of BCR in high-risk PCa patients. A two-gene continuous DNA methylation model "PITX2 × 0.020677 + HOXD3 × 0.0043132" is a better predictor of BCR compared with individual markers.
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Endometriosis is a gynecologic disease that is characterized by nonspecific symptoms and invasive diagnostics. To date, there is no adequate noninvasive method for the diagnosis of endometriosis. Although more than 100 potential biomarkers have been investigated in blood and/or peritoneal fluid, none of these has proven useful in clinical practice. The aim to find a suitable panel of biomarkers that would allow noninvasive diagnosis thus remains of interest. We evaluated the concentrations of 16 cytokines and other secretory proteins in serum and peritoneal fluid of 58 women with ovarian endometriosis (cases) and 40 healthy women undergoing sterilization or patients with benign ovarian cysts (controls) using multiplexed double fluorescence-based immunometric assay platform and enzyme-linked immunosorbent assay. Significantly higher concentrations of glycodelin-A were shown in serum, and significantly higher levels of glycodelin-A, IL-6, and IL-8, and lower levels of leptin were measured in the peritoneal fluid of cases versus controls. In serum, the best performance was shown by models that included the ratio of leptin/glycodelin-A and the ratio of ficolin 2/glycodelin-A, whereas in the peritoneal fluid the best models included the ratio of biglycan/leptin, regulated on activation normal T-cell expressed and secreted/IL-6 and ficolin-2/glycodelin-A, and IL-8 per milligram of total protein, all in combination with age. The models using serum and peritoneal fluid distinguished between ovarian endometriosis patients and controls regardless of the menstrual cycle phase with relatively high sensitivity (72.5% to 84.2%), specificity (78.4% to 91.2%), and area under the curve (0.85 to 0.90).
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Localized prostate cancer (PCa) is a clinically heterogeneous disease, which presents with variability in patient outcomes within the same risk stratification (low, intermediate or high) and even within the same Gleason scores. Genomic tools have been developed with the purpose of stratifying patients affected by this disease to help physicians personalize therapies and follow-up schemes. This review focuses on these tissue-based tools. At present, four genomic tools are commercially available: Decipher™, Oncotype DX®, Prolaris® and ProMark®. Decipher™ is a tool based on 22 genes and evaluates the risk of adverse outcomes (metastasis) after radical prostatectomy (RP). Oncotype DX® is based on 17 genes and focuses on the ability to predict outcomes (adverse pathology) in very low-low and low-intermediate PCa patients, while Prolaris® is built on a panel of 46 genes and is validated to evaluate outcomes for patients at low risk as well as patients who are affected by high risk PCa and post-RP. Finally, ProMark® is based on a multiplexed proteomics assay and predicts PCa aggressiveness in patients found with similar features to Oncotype DX®. These biomarkers can be helpful for post-biopsy decision-making in low risk patients and post-radical prostatectomy in selected risk groups. Further studies are needed to investigate the clinical benefit of these new technologies, the financial ramifications and how they should be utilized in clinics.