A PbS quantum-cube: conducting polymer composite for photovoltaic applications

We have developed a new non-polar synthesis for lead sulfide (PbS) quantum-cubes in the conjugated polymer poly-2-methoxy, 5-(2-ethyl-hexyloxy-p-phenylenevinylene) MEH-PPV. The conducting polymer acts to template and control the quantum-cube growth. Transmission electron microscopy of the composites has shown a bimodal distribution of cube sizes between 5 and 15 nm is produced with broad optical absorption from 300 to 650 nm. Photoluminescence suggests electronic coupling between the cubes and the conducting polymer matrix. The synthesis and initial characterization are presented in this paper. (C) 2003 Elsevier B.V. All rights reserved.

A new approach to the synthesis of nanocrystal conjugated polymer composites

A novel one pot process has been developed for the preparation of PbS nanocrystals in the conjugated polymer poly 2-methoxy,5-(2 ethyl-hexyloxy-p-phenylenevinylene) (MEH-PPV). Current techniques for making such composite materials rely upon synthesizing the nanocrystals and conducting polymer separately, and subsequently mixing them. This multi-step technique has two serious drawbacks: templating surfactant must be removed before mixing, and co-solvent incompatibility causes aggregation. In our method, we eliminate the need for an initial surfactant by using the conducting polymer to terminate and template nanocrystal growth. Additionally, the final product is soluble in a single solvent. We present materials analysis which shows PbS nanocrystals can be grown directly in a conducting polymer, the resulting composite is highly ordered and nanocrystal size can be controlled.

Growing semiconductor nanocrystals directly in a conducting polymer

We describe a single step method to synthesise lead sulphide (PbS) nanocrystals directly in the conjugated polymer poly (2-methoxy-5-(2'-ethyl-hexyloxy)-p-phenylene vinylene) (MEH-PPV). This method allows size control of the nanocrystal via co-solvent ratios. We find good agreement between nanocrystal sizes determined by transmission electron microscopy and sizes theoretically determined from the absorption edge of the nanocrystals. Finally we show that this synthesis technique is not restricted to MEH-PPV and demonstrate that nanocrystals can be grown in Poly(3-hexylthiophene-2,5-diyl) (P3HT). (C) 2005 Elsevier B.V. All rights reserved.

Lead sulfide nanocrystal: conducting polymer solar cells

In this paper, we report photovoltaic devices fabricated from lead sulfide nanocrystals and the conducting polymer poly(2-methoxy-5-(2'-ethyl-hexyloxy)-p-phenylene vinylene). This composite material was produced via a new single-pot synthesis which solves many of the issues associated with existing methods. Our devices have white light power conversion efficiencies under AM 1.5 illumination of 0.7% and single wavelength conversion efficiencies of 1.1%. Additionally, they exhibit remarkably good ideality factors (n = 1.15). Our measurements show that these composites have significant potential as soft optoelectronic materials.

Energy transfer dynamics of nanocrystal-polymer composites

Steady-state and time-resolved photoluminescence spectroscopy are used to examine the photoluminescent properties of nanocrystal-polymer composites consisting of colloidal PbS nanocrystals blended with poly(2-methoxy-5(2-ethylhexyloxy)-p-phenylene vinylene). Quenching of the emission from the conjugated polymer due to the PbS nanocrystals is observed along with band edge emission from the ligand capped PbS nanocrystals. A decrease in the photoluminescence lifetime of MEH-PPV is also observed in the thin film nanocrystal-polymer composite materials. Photoluminescence excitation spectroscopy of the PbS nanocrystal emission from the composite shows features attributed to MEH-PPV providing evidence of a Forster transfer process.

Carrier transport in PbS nanocrystal conducting polymer composites

In this letter we report the carrier mobilities in an inorganic nanocrystal: conducting polymer composite. The composite material in question (lead sulphide nanocrystals in the conducting polymer poly [2-methoxy-5-(2(')-ethyl-hexyloxy)-p-phenylene vinylene] (MEH-PPV) was made using a single-pot, surfactant-free synthesis. Mobilties were measured using time of flight techniques. We have found that the inclusion of PbS nanocrystals in MEH-PPV both balances and markedly increases the hole and electron mobilities-the hole mobility is increased by a factor of similar to 10(5) and the electron mobility increased by similar to 10(7) under an applied bias of 5 kV cm(-1). These results explain why dramatic improvements in electrical conductivity and photovoltaic performance are seen in devices fabricated from these composites.

Seizure detection algorithm for neonates based on wave-sequence analysis

Objective: The description and evaluation of the performance of a new real-time seizure detection algorithm in the newborn infant. Methods: The algorithm includes parallel fragmentation of EEG signal into waves; wave-feature extraction and averaging; elementary, preliminary and final detection. The algorithm detects EEG waves with heightened regularity, using wave intervals, amplitudes and shapes. The performance of the algorithm was assessed with the use of event-based and liberal and conservative time-based approaches and compared with the performance of Gotman's and Liu's algorithms. Results: The algorithm was assessed on multi-channel EEG records of 55 neonates including 17 with seizures. The algorithm showed sensitivities ranging 83-95% with positive predictive values (PPV) 48-77%. There were 2.0 false positive detections per hour. In comparison, Gotman's algorithm (with 30 s gap-closing procedure) displayed sensitivities of 45-88% and PPV 29-56%; with 7.4 false positives per hour and Liu's algorithm displayed sensitivities of 96-99%, and PPV 10-25%; with 15.7 false positives per hour. Conclusions: The wave-sequence analysis based algorithm displayed higher sensitivity, higher PPV and a substantially lower level of false positives than two previously published algorithms. Significance: The proposed algorithm provides a basis for major improvements in neonatal seizure detection and monitoring. Published by Elsevier Ireland Ltd. on behalf of International Federation of Clinical Neurophysiology.

Avaliação comparativa da eficácia dos meios de diagnóstico das vulvovaginites: implantação de tecnologia no ensino prático da ginecologia

Inaccurate diagnosis of vulvovaginitis generates inadequate treatments that cause damages women's health. Objective: evaluate the effectiveness of methods when diagnosing vulvovaginitis. Method: a cross-sectional study was performed with 200 women who complained about vaginal discharge. Vaginal smear was collected for microbiological tests, considering the gram stain method as gold standard. The efficacy of the available methods for diagnosis of vaginal discharge was assessed (sensitivity, specificity, positive predictive value and negative predictive value). Data were inserted to Graphpad Prism 6, for statistical analysis. Results: the following results were obtained: wet mount for vaginal candidiasis: sensitivity = 31%; specificity = 97%; positive predictive value (PPV) = 54%; negative predictive value (NPV) =93%; accuracy = 91%. Wet mount for bacterial vaginosis: sensitivity = 80%; specificity =95%; positive predictive value (PPV) = 80%; negative predictive value (NPV) = 95%; accuracy = 92%. Syndromic approach for bacterial vaginosis: sensitivity = 95%; specificity=43%; positive predictive value (PPV) =30%; negative predictive value (NPV) = 97%; accuracy = 54%. Syndromic approach for vaginal candidiasis: sensitivity = 75%; specificity =91%; positive predictive value (PPV) = 26%; negative predictive value (NPV) = 98%; accuracy = 90%. Pap smear for vaginal candidiasis: sensitivity = 68%, specificity = 98%; positive predictive value (PPV) = 86%; negative predictive value (NPV) =96%; accuracy = 96%. Pap smear for bacterial vaginosis: sensitivity = 75%; specificity = 100%; positive predictive value (PPV) = 100%; negative predictive value (NPV) =94%; accuracy = 95%. There was only one case of vaginal trichomoniasis reported – diagnosed by oncological cytology and wet mount – confirmed by Gram. The syndromic approach diagnosed it as bacterial vaginosis. From the data generated and with support on world literature, the Maternidade Escola Januário Cicco’s vulvovaginitis protocol was constructed. Conclusion: Pap smear and wet mount showed respectively low and very low sensitivity for vaginal candidiasis. Syndromic approach presented very low specificity and accuracy for bacterial vaginosis, which implies a large number of patients who are diagnosed or treated incorrectly.

An evaluation of physician predictions of discharge on a general medicine service.

The goal of this study was to evaluate general medicine physicians' ability to predict hospital discharge. We prospectively asked study subjects to predict whether each patient under their care would be discharged on the next day, on the same day, or neither. Discharge predictions were recorded at 3 time points: mornings (7-9 am), midday (12-2 pm), or afternoons (5-7 pm), for a total of 2641 predictions. For predictions of next-day discharge, the sensitivity (SN) and positive predictive value (PPV) were lowest in the morning (27% and 33%, respectively), but increased by the afternoon (SN 67%, PPV 69%). Similarly, for same-day discharge predictions, SN and PPV were highest at midday (88% and 79%, respectively). We found that although physicians have difficulty predicting next-day discharges in the morning prior to the day of expected discharge, their ability to correctly predict discharges continually improved as the time to actual discharge decreased. Journal of Hospital Medicine 2015;10:808-810. © 2015 Society of Hospital Medicine.

Assessment of Two Diabetes Point-of-Care Analyzers Measuring Hemoglobin A1c in the Peruvian Amazon

Aims: Measurement of glycated hemoglobin (HbA1c) is an important indicator of glucose control over time. Point-of-care (POC) devices allow for rapid and convenient measurement of HbA1c, greatly facilitating diabetes care. We assessed two POC analyzers in the Peruvian Amazon where laboratory-based HbA1c testing is not available.

Methods: Venous blood samples were collected from 203 individuals from six different Amazonian communities with a wide range of HbA1c, 4.4-9.0% (25-75 mmol/mol). The results of the Afinion AS100 and the DCA Vantage POC analyzers were compared to a central laboratory using the Premier Hb9210 high-performance liquid chromatography (HPLC) method. Imprecision was assessed by performing 14 successive tests of a single blood sample.

Results: The correlation coefficient r for POC and HPLC results was 0.92 for the Afinion and 0.93 for the DCA Vantage. The Afinion generated higher HbA1c results than the HPLC (mean difference = +0.56% [+6 mmol/mol]; p < 0.001), as did the DCA Vantage (mean difference = +0.32% [4 mmol/mol]). The bias observed between POC and HPLC did not vary by HbA1c level for the DCA Vantage (p = 0.190), but it did for the Afinion (p < 0.001). Imprecision results were: CV = 1.75% for the Afinion, CV = 4.01% for the DCA Vantage. Sensitivity was 100% for both devices, specificity was 48.3% for the Afinion and 85.1% for the DCA Vantage, positive predictive value (PPV) was 14.4% for the Afinion and 34.9% for the DCA Vantage, and negative predictive value (NPV) for both devices was 100%. The area under the receiver operating characteristic (ROC) curve was 0.966 for the Afinion and 0.982 for the DCA Vantage. Agreement between HPLC and POC in classifying diabetes and prediabetes status was slight for the Afinion (Kappa = 0.12) and significantly different (McNemar’s statistic = 89; p < 0.001), and moderate for the DCA Vantage (Kappa = 0.45) and significantly different (McNemar’s statistic = 28; p < 0.001).

Conclusions: Despite significant variation of HbA1c results between the Afinion and DCA Vantage analyzers compared to HPLC, we conclude that both analyzers should be considered in health clinics in the Peruvian Amazon for therapeutic adjustments if healthcare workers are aware of the differences relative to testing in a clinical laboratory. However, imprecision and bias were not low enough to recommend either device for screening purposes, and the local prevalence of anemia and malaria may interfere with diagnostic determinations for a substantial portion of the population.

Excitonic behaviour in polymeric semiconductors : the effect of morphology and composition in heterostructures

La compréhension des interrelations entre la microstructure et les processus électroniques dans les polymères semi-conducteurs est d’une importance primordiale pour leur utilisation dans des hétérostructures volumiques. Dans cette thèse de doctorat, deux systémes diffèrents sont étudiés ; chacun de ces systèmes représente une approche diffèrente pour optimiser les matériaux en termes de leur microstructure et de leur capacité à se mettre en ordre au niveau moléculaire. Dans le premier système, j’ai effectué une analyse complète des principes de fonctionnement d’une cellule photovoltaïque hybride à base des nanocristaux d’oxyde de zinc (ZnO) et du poly (3-hexylthiophène) (P3HT) par absorption photoinduite en régime quasi-stationnaire (PIA) et la spectroscopie PIA en pompage modulé dépendant de la fréquence. L’interface entre le donneur (le polymère P3HT) et l’accepteur (les nanoparticules de ZnO), où la génération de charges se produit, joue un rôle important dans la performance des cellules photovoltaïques hybrides. Pour améliorer le mécanisme de génération de charges du P3H: ZnO, il est indispensable de modifier l’interface entre ses constituants. Nous avons démontré que la modification d’interface moléculaire avec cis-bis (4, 40 - dicarboxy-2, 20bipyridine) ruthénium (II) (N3-dye) et a-Sexithiophen-2 yl-phosphonique (6TP) a améliorée le photocourant et la performance dans les cellules P3HT: ZnO. Le 6TP et le N3 s’attachent à l’interface du ZnO, en augmentant ainsi l’aire effective de la surface donneur :accepteur, ce qui contribue à une séparation de charge accrue. De plus, le 6TP et le N3 réduisent la densité de pièges dans le ZnO, ce qui réduit le taux de recombinaison des paires de charges. Dans la deuxième partie, jai introduit une matrice hôte polymérique de polystyréne à masse molaire ulra-élevée, qui se comporte comme un solide pour piéger et protéger une solution de poly [2-méthoxy, 5- (2´-éthyl-hexoxy) -1,4-phénylènevinylène- PPV] (MEHPPV) pour utilisation dans des dispositifs optoèlectroniques quantiques. Des travaux antérieurs ont montré que MEH-PPV en solution subit une transition de conformation, d’une conformation enroulé à haute température (phase bleue) à une conformation de chaîne étendue à basse température (phase rouge). La conformation de la chaîne étendue de la solution MEH-PPV favorise les caractéristiques nécessaires à l’amélioration des dispositifs optoélectroniques quantiques, mais la solution ne peut pas être incorporées dans le dispositif. J’ai démontré que la caractéristique de la phase rouge du MEH-PPV en solution se maintient dans une matrice hôte polymérique de polystyrène transformé de masse molaire très élevée, qui se comporte comme un solide (gel de MEH-PPV/UHMW PS), par le biais de la spectroscopie de photoluminescence (PL) dépendant de la température (de 290K à 80 K). La phase rouge du gel MEH-PPV/UHMW PS se manifeste par des largeurs de raie étroites et une intensité augmentée de la transition 0-0 de la progression vibronique dans le spectre de PL ainsi qu’un petit décalage de Stokes entre la PL et le spectre d’absorption à basse température. Ces approches démontrent que la manipulation de la microstructure et des propriétés électroniques des polymères semi-conducteurs ont un impact direct sur la performance de dispositifs pour leurs développements technologiques continus.

Validation of Electronic Health Record Phenotyping of Bipolar Disorder Cases and Controls

Objective: The study was designed to validate use of elec-tronic health records (EHRs) for diagnosing bipolar disorder and classifying control subjects. Method: EHR data were obtained from a health care system of more than 4.6 million patients spanning more than 20 years. Experienced clinicians reviewed charts to identify text features and coded data consistent or inconsistent with a diagnosis of bipolar disorder. Natural language processing was used to train a diagnostic algorithm with 95% specificity for classifying bipolar disorder. Filtered coded data were used to derive three additional classification rules for case subjects and one for control subjects. The positive predictive value (PPV) of EHR-based bipolar disorder and subphenotype di- agnoses was calculated against diagnoses from direct semi- structured interviews of 190 patients by trained clinicians blind to EHR diagnosis. Results: The PPV of bipolar disorder defined by natural language processing was 0.85. Coded classification based on strict filtering achieved a value of 0.79, but classifications based on less stringent criteria performed less well. No EHR- classified control subject received a diagnosis of bipolar dis- order on the basis of direct interview (PPV=1.0). For most subphenotypes, values exceeded 0.80. The EHR-based clas- sifications were used to accrue 4,500 bipolar disorder cases and 5,000 controls for genetic analyses. Conclusions: Semiautomated mining of EHRs can be used to ascertain bipolar disorder patients and control subjects with high specificity and predictive value compared with diagnostic interviews. EHRs provide a powerful resource for high-throughput phenotyping for genetic and clinical research.

Revisiting molecular diagnostics of Streptococcus pneumoniae

Streptococcus pneumoniae is a human pathobiont that colonizes the nasopharynx. S. pneumoniae is responsible for causing non-invasive and invasive disease such as otitis, pneumonia, meningitis, and sepsis, being a leading cause of infectious diseases worldwide. Due to similarities with closely related species sharing the same niche, it may be a challenge to correctly distinguish S. pneumoniae from its relatives when using only non-culture based methods such as real time PCR (qPCR). In 2007, a molecular method targeting the major autolysin (lytA) of S. pneumoniae by a qPCR assay was proposed by Carvalho and collaborators to identify pneumococcus. Since then, this method has been widely used worldwide. In 2013, the gene encoding for the ABC iron transporter lipoprotein PiaA, was proposed by Trzcinzki and collaborators to be used in parallel with the lytA qPCR assay. However, the presence of lytA gene homologues has been described in closely related species such as S. pseudopneumoniae and S. mitis and the presence of piaA gene is not ubiquitous between S. pneumoniae. The hyaluronate lyase gene (hylA) has been described to be ubiquitous in S. pneumoniae. This gene has not been used so far as a target for the identification of S. pneumoniae. The aims of our study were to evaluate the specificity, sensitivity, positive predicted value (PPV) and negative predicted value (NPV) of the lytA and piaA qPCR methods; design and implement a new assay targeting the hylA gene and evaluate the same parameters above described; analyze the assays independently and the possible combinations to access what is the best approach using qPCR to identify S. pneumoniae. A total of 278 previously characterized strains were tested: 61 S. pseudopneumoniae, 37 Viridans group strains, 30 type strains from other streptococcal species and 150 S. pneumoniae strains. The collection included both carriage and disease isolates. By Mulilocus Sequence Analysis (MLSA) we confirmed that strains of S. pseudopneumoniae could be misidentified as S. pneumoniae when lytA qPCR assay is used. The results showed that as a single target, lytA had the best combination of specificity, sensitivity, PPV and NPV being, 98.5%, 100.0%, 98.7% and 100.0% respectively. The combination of targets with the best values of specificity, sensibility, PPV and NPV were lytA and piaA, with 100.0%, 93.3%, 97.9% and 92.6%, respectively. Nonetheless by MLSA we confirmed that strains of S. pseudopneumoniae could be misidentified as S. pneumoniae and some capsulated (23F, 6B and 11A) and non-capsulated S. pneumoniae were not Identified using this assay. The hylA gene as a single target had the lowest PPV. Nonetheless it was capable to correctly identify all S. pneumoniae.

Excitonic behaviour in polymeric semiconductors : the effect of morphology and composition in heterostructures

La compréhension des interrelations entre la microstructure et les processus électroniques dans les polymères semi-conducteurs est d’une importance primordiale pour leur utilisation dans des hétérostructures volumiques. Dans cette thèse de doctorat, deux systémes diffèrents sont étudiés ; chacun de ces systèmes représente une approche diffèrente pour optimiser les matériaux en termes de leur microstructure et de leur capacité à se mettre en ordre au niveau moléculaire. Dans le premier système, j’ai effectué une analyse complète des principes de fonctionnement d’une cellule photovoltaïque hybride à base des nanocristaux d’oxyde de zinc (ZnO) et du poly (3-hexylthiophène) (P3HT) par absorption photoinduite en régime quasi-stationnaire (PIA) et la spectroscopie PIA en pompage modulé dépendant de la fréquence. L’interface entre le donneur (le polymère P3HT) et l’accepteur (les nanoparticules de ZnO), où la génération de charges se produit, joue un rôle important dans la performance des cellules photovoltaïques hybrides. Pour améliorer le mécanisme de génération de charges du P3H: ZnO, il est indispensable de modifier l’interface entre ses constituants. Nous avons démontré que la modification d’interface moléculaire avec cis-bis (4, 40 - dicarboxy-2, 20bipyridine) ruthénium (II) (N3-dye) et a-Sexithiophen-2 yl-phosphonique (6TP) a améliorée le photocourant et la performance dans les cellules P3HT: ZnO. Le 6TP et le N3 s’attachent à l’interface du ZnO, en augmentant ainsi l’aire effective de la surface donneur :accepteur, ce qui contribue à une séparation de charge accrue. De plus, le 6TP et le N3 réduisent la densité de pièges dans le ZnO, ce qui réduit le taux de recombinaison des paires de charges. Dans la deuxième partie, jai introduit une matrice hôte polymérique de polystyréne à masse molaire ulra-élevée, qui se comporte comme un solide pour piéger et protéger une solution de poly [2-méthoxy, 5- (2´-éthyl-hexoxy) -1,4-phénylènevinylène- PPV] (MEHPPV) pour utilisation dans des dispositifs optoèlectroniques quantiques. Des travaux antérieurs ont montré que MEH-PPV en solution subit une transition de conformation, d’une conformation enroulé à haute température (phase bleue) à une conformation de chaîne étendue à basse température (phase rouge). La conformation de la chaîne étendue de la solution MEH-PPV favorise les caractéristiques nécessaires à l’amélioration des dispositifs optoélectroniques quantiques, mais la solution ne peut pas être incorporées dans le dispositif. J’ai démontré que la caractéristique de la phase rouge du MEH-PPV en solution se maintient dans une matrice hôte polymérique de polystyrène transformé de masse molaire très élevée, qui se comporte comme un solide (gel de MEH-PPV/UHMW PS), par le biais de la spectroscopie de photoluminescence (PL) dépendant de la température (de 290K à 80 K). La phase rouge du gel MEH-PPV/UHMW PS se manifeste par des largeurs de raie étroites et une intensité augmentée de la transition 0-0 de la progression vibronique dans le spectre de PL ainsi qu’un petit décalage de Stokes entre la PL et le spectre d’absorption à basse température. Ces approches démontrent que la manipulation de la microstructure et des propriétés électroniques des polymères semi-conducteurs ont un impact direct sur la performance de dispositifs pour leurs développements technologiques continus.

Giza papilomabirusa eta umetoki lepoko minbizia: aldakortasun genetikoa, biomarkatzaileak eta epidemiologia

148 p.