Sensitive electrochemical immunosensor for α-synuclein based on dual signal amplification using PAMAM dendrimer-encapsulated Au and enhanced gold nanoparticle labels.

PubMed

An, Yarui; Jiang, Xiaoli; Bi, Wenji; Chen, Hua; Jin, Litong; Zhang, Shengping; Wang, Chuangui; Zhang, Wen

2012-02-15

A novel electrochemical immunosensor for sensitive detection of α-synuclein (α-SYN), a very important neuronal protein, has been developed based on dual signal amplification strategy. Herein, G4-polyamidoamine dendrimer-encapsulated Au nanoparticles (PAMAM-Au nanocomposites) were covalently bound on the poly-o-aminobenzoic acid (poly-o-ABA), which was initially electropolymerized on the electrode surface to perform abundant carboxyl groups. The formed immunosensor platform, PAMAM-Au, was proved to provide numerous amino groups to allow highly dense immobilization of antigen, and facilitate the improvement of electrochemical responses as well. Subsequently, the enhanced gold nanoparticle labels ({HRP-Ab(2)-GNPs}) were fabricated by immobilizing horseradish peroxidase-secondary antibody (HRP-Ab(2)) on the surface of gold nanoparticles (GNPs). After an immunoassay process, the {HRP-Ab(2)-GNPs} labels were introduced onto the electrode surface, and produced an electrocatalytic response by reduction of hydrogen peroxide (H(2)O(2)) in the presence of enzymatically oxidized thionine. On the basis of the dual signal amplification of PAMAM-Au and {HRP-Ab(2)-GNPs} labels, the designed immunosensor displayed an excellent analytical performance with high sensitivity and stability. This developed strategy was successfully proved as a simple, cost-effective method, and could be easily extended to other protein analysis schemes. Copyright © 2011 Elsevier B.V. All rights reserved.

Is there a place for extended assessments in addressing child sexual abuse allegations? How sensitivity and specificity impact professional perspectives.

PubMed

Williams, Javonda; Nelson-Gardell, Debra; Coulborn Faller, Kathleen; Tishelman, Amy; Cordisco-Steele, Linda

2014-01-01

Using data from a survey of perceptions of 932 child welfare professionals about the utility of extended assessments, the researchers constructed a scale to measure respondents' views about sensitivity (ensuring sexually abused children are correctly identified) and specificity (ensuring nonabused children are correctly identified) in child sexual abuse evaluations. On average, respondents scored high (valuing sensitivity) on the sensitivity versus specificity scale. Next, the researchers undertook bivariate analyses to identify independent variables significantly associated with the sensitivity versus specificity scale. Then those variables were entered into a multiple regression. Four independent variables were significantly related to higher sensitivity scores: encountering cases requiring extended assessments, valuing extended assessments among scarce resources, less concern about proving cases in court, and viewing the goal of extended assessments as understanding needs of child and family (adjusted R2 = .34).

A two-step lyssavirus real-time polymerase chain reaction using degenerate primers with superior sensitivity to the fluorescent antigen test.

PubMed

Suin, Vanessa; Nazé, Florence; Francart, Aurélie; Lamoral, Sophie; De Craeye, Stéphane; Kalai, Michael; Van Gucht, Steven

2014-01-01

A generic two-step lyssavirus real-time reverse transcriptase polymerase chain reaction (qRT-PCR), based on a nested PCR strategy, was validated for the detection of different lyssavirus species. Primers with 17 to 30% of degenerate bases were used in both consecutive steps. The assay could accurately detect RABV, LBV, MOKV, DUVV, EBLV-1, EBLV-2, and ABLV. In silico sequence alignment showed a functional match with the remaining lyssavirus species. The diagnostic specificity was 100% and the sensitivity proved to be superior to that of the fluorescent antigen test. The limit of detection was ≤ 1 50% tissue culture infectious dose. The related vesicular stomatitis virus was not recognized, confirming the selectivity for lyssaviruses. The assay was applied to follow the evolution of rabies virus infection in the brain of mice from 0 to 10 days after intranasal inoculation. The obtained RNA curve corresponded well with the curves obtained by a one-step monospecific RABV-qRT-PCR, the fluorescent antigen test, and virus titration. Despite the presence of degenerate bases, the assay proved to be highly sensitive, specific, and reproducible.

A Two-Step Lyssavirus Real-Time Polymerase Chain Reaction Using Degenerate Primers with Superior Sensitivity to the Fluorescent Antigen Test

PubMed Central

Nazé, Florence; Francart, Aurélie; Lamoral, Sophie; De Craeye, Stéphane; Kalai, Michael

2014-01-01

A generic two-step lyssavirus real-time reverse transcriptase polymerase chain reaction (qRT-PCR), based on a nested PCR strategy, was validated for the detection of different lyssavirus species. Primers with 17 to 30% of degenerate bases were used in both consecutive steps. The assay could accurately detect RABV, LBV, MOKV, DUVV, EBLV-1, EBLV-2, and ABLV. In silico sequence alignment showed a functional match with the remaining lyssavirus species. The diagnostic specificity was 100% and the sensitivity proved to be superior to that of the fluorescent antigen test. The limit of detection was ≤1 50% tissue culture infectious dose. The related vesicular stomatitis virus was not recognized, confirming the selectivity for lyssaviruses. The assay was applied to follow the evolution of rabies virus infection in the brain of mice from 0 to 10 days after intranasal inoculation. The obtained RNA curve corresponded well with the curves obtained by a one-step monospecific RABV-qRT-PCR, the fluorescent antigen test, and virus titration. Despite the presence of degenerate bases, the assay proved to be highly sensitive, specific, and reproducible. PMID:24822188

Prospective Comparison of a New Chromogenic Medium, MRSASelect, to CHROMagar MRSA and Mannitol-Salt Medium Supplemented with Oxacillin or Cefoxitin for Detection of Methicillin-Resistant Staphylococcus aureus

PubMed Central

Stoakes, Luba; Reyes, Romina; Daniel, Janis; Lennox, Gwen; John, Michael A.; Lannigan, Robert; Hussain, Zafar

2006-01-01

MRSASelect agar was compared to CHROMagar, mannitol-salt agar with oxacillin, and mannitol-salt agar with cefoxitin (MSA-CFOX) for the isolation of methicillin-resistant Staphylococcus aureus (MRSA). The sensitivities and specificities were 97.3% and 99.8%, 82.9% and 99.1%, 80.2% and 79%, and 99.1% and 84.8%, respectively. MSA-CFOX and MRSASelect had a high sensitivity. MRSASelect, however, was more specific and proved to be a more reliable and rapid medium for the detection of MRSA. PMID:16455933

Experimental evidence for the sensitivity of the air-shower radio signal to the longitudinal shower development

NASA Astrophysics Data System (ADS)

Apel, W. D.; Arteaga, J. C.; Bähren, L.; Bekk, K.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.; Brancus, I. M.; Buchholz, P.; Cantoni, E.; Chiavassa, A.; Daumiller, K.; de Souza, V.; Di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Finger, M.; Fuchs, B.; Fuhrmann, D.; Gemmeke, H.; Grupen, C.; Haungs, A.; Heck, D.; Hörandel, J. R.; Horneffer, A.; Huber, D.; Huege, T.; Isar, P. G.; Kampert, K.-H.; Kang, D.; Krömer, O.; Kuijpers, J.; Link, K.; Łuczak, P.; Ludwig, M.; Mathes, H. J.; Melissas, M.; Morello, C.; Oehlschläger, J.; Palmieri, N.; Pierog, T.; Rautenberg, J.; Rebel, H.; Roth, M.; Rühle, C.; Saftoiu, A.; Schieler, H.; Schmidt, A.; Schröder, F. G.; Sima, O.; Toma, G.; Trinchero, G. C.; Weindl, A.; Wochele, J.; Wommer, M.; Zabierowski, J.; Zensus, J. A.

2012-04-01

We observe a correlation between the slope of radio lateral distributions and the mean muon pseudorapidity of 59 individual cosmic-ray-air-shower events. The radio lateral distributions are measured with LOPES, a digital radio interferometer colocated with the multidetector-air-shower array KASCADE-Grande, which includes a muon-tracking detector. The result proves experimentally that radio measurements are sensitive to the longitudinal development of cosmic-ray air showers. This is one of the main prerequisites for using radio arrays for ultra-high-energy particle physics and astrophysics.

High sensitive and direct fluorescence detection of single viral DNA sequences by integration of double strand probes onto microgels particles.

PubMed

Aliberti, A; Cusano, A M; Battista, E; Causa, F; Netti, P A

2016-02-21

A novel class of probes for fluorescence detection was developed and combined to microgel particles for a high sensitive fluorescence detection of nucleic acids. A double strand probe with an optimized fluorescent-quencher couple was designed for the detection of different lengths of nucleic acids (39 nt and 100 nt). Such probe proved efficient in target detection in different contests and specific even in presence of serum proteins. The conjugation of double strand probes onto polymeric microgels allows for a sensitive detection of DNA sequences from HIV, HCV and SARS corona viruses with a LOD of 1.4 fM, 3.7 fM and 1.4 fM, respectively, and with a dynamic range of 10(-9)-10(-15) M. Such combination enhances the sensitivity of the detection of almost five orders of magnitude when compared to the only probe. The proposed platform based on the integration of innovative double strand probe into microgels particles represents an attractive alternative to conventional sensitive DNA detection technologies that rely on amplifications methods.

Incorporating resource protection constraints in an analysis of landscape fuel-treatment effectiveness in the northern Sierra Nevada, CA, USA

Treesearch

Christopher B. Dow; Brandon M. Collins; Scott L. Stephens

2016-01-01

Finding novel ways to plan and implement landscape-level forest treatments that protect sensitive wildlife and other key ecosystem components, while also reducing the risk of large-scale, high-severity fires, can prove to be difficult. We examined alternative approaches to landscape-scale fuel-treatment design for the same landscape. These approaches included two...

Synthesis and Characterization of a New Co-Crystal Explosive with High Energy and Good Sensitivity

NASA Astrophysics Data System (ADS)

Gao, Han; Jiang, Wei; Liu, Jie; Hao, Gazi; Xiao, Lei; Ke, Xiang; Chen, Teng

2017-10-01

A new energetic co-crystal consisting of one of the most powerful explosive molecules 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) and the military explosive cyclotrimethylenetrinitramine (RDX) was prepared with a simple solvent evaporation method. Scanning electron microscopy (SEM) revealed the morphology of the bar-shaped product, which differed greatly from the morphology of the individual components. Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction spectrum (XRD), and differential scanning calorimetry (DSC) proved the formation of the co-crystal at the molecular level. The result of mechanical sensitivity test indicated the sensitivity was effectively reduced compared to raw CL-20. Finally, a possible crystallization mechanism was discussed.

Self-assembled micelles based on pH-sensitive PAE-g-MPEG-cholesterol block copolymer for anticancer drug delivery.

PubMed

Zhang, Can Yang; Xiong, Di; Sun, Yao; Zhao, Bin; Lin, Wen Jing; Zhang, Li Juan

2014-01-01

A novel amphiphilic triblock pH-sensitive poly(β-amino ester)-g-poly(ethylene glycol) methyl ether-cholesterol (PAE-g-MPEG-Chol) was designed and synthesized via the Michael-type step polymerization and esterification condensation method. The synthesized copolymer was determined with proton nuclear magnetic resonance and gel permeation chromatography. The grafting percentages of MPEG and cholesterol were determined as 10.93% and 62.02%, calculated from the area of the characteristic peaks, respectively. The amphiphilic copolymer was confirmed to self-assemble into core/shell micelles in aqueous solution at low concentrations. The critical micelle concentrations were 6.92 and 15.14 mg/L at pH of 7.4 and 6.0, respectively, obviously influenced by the changes of pH values. The solubility of pH-responsive PAE segment could be transformed depending on the different values of pH because of protonation-deprotonation of the amino groups, resulting in pH sensitivity of the copolymer. The average particle size of micelles increased from 125 nm to 165 nm with the pH decreasing, and the zeta potential was also significantly changed. Doxorubicin (DOX) was entrapped into the polymeric micelles with a high drug loading level. The in vitro DOX release from the micelles was distinctly enhanced with the pH decreasing from 7.4 to 6.0. Toxicity testing proved that the DOX-loaded micelles exhibited high cytotoxicity in HepG2 cells, whereas the copolymer showed low toxicity. The results demonstrated how pH-sensitive PAE-g-MPEG-Chol micelles were proved to be a potential vector in hydrophobic drug delivery for tumor therapy.

Self-assembled micelles based on pH-sensitive PAE-g-MPEG-cholesterol block copolymer for anticancer drug delivery

PubMed Central

Zhang, Can Yang; Xiong, Di; Sun, Yao; Zhao, Bin; Lin, Wen Jing; Zhang, Li Juan

2014-01-01

A novel amphiphilic triblock pH-sensitive poly(β-amino ester)-g-poly(ethylene glycol) methyl ether-cholesterol (PAE-g-MPEG-Chol) was designed and synthesized via the Michael-type step polymerization and esterification condensation method. The synthesized copolymer was determined with proton nuclear magnetic resonance and gel permeation chromatography. The grafting percentages of MPEG and cholesterol were determined as 10.93% and 62.02%, calculated from the area of the characteristic peaks, respectively. The amphiphilic copolymer was confirmed to self-assemble into core/shell micelles in aqueous solution at low concentrations. The critical micelle concentrations were 6.92 and 15.14 mg/L at pH of 7.4 and 6.0, respectively, obviously influenced by the changes of pH values. The solubility of pH-responsive PAE segment could be transformed depending on the different values of pH because of protonation–deprotonation of the amino groups, resulting in pH sensitivity of the copolymer. The average particle size of micelles increased from 125 nm to 165 nm with the pH decreasing, and the zeta potential was also significantly changed. Doxorubicin (DOX) was entrapped into the polymeric micelles with a high drug loading level. The in vitro DOX release from the micelles was distinctly enhanced with the pH decreasing from 7.4 to 6.0. Toxicity testing proved that the DOX-loaded micelles exhibited high cytotoxicity in HepG2 cells, whereas the copolymer showed low toxicity. The results demonstrated how pH-sensitive PAE-g-MPEG-Chol micelles were proved to be a potential vector in hydrophobic drug delivery for tumor therapy. PMID:25364250

Non-invasive and high-sensitivity scanning detection of magnetic nanoparticles in animals using high-Tc scanning superconducting-quantum-interference-device biosusceptometry.

PubMed

Chieh, J J; Hong, C Y

2011-08-01

Although magnetic nanoparticles (MNPs) have been widely applied to animals in biomedicine, MNPs within animals should be examined in real time, in vivo, and without bio-damaged possibility to evaluate whether the bio-function of MNPs is valid or to further controls the biomedicinal process because of accompanying complex problems such as MNPs distribution and MNPs biodegradation. The non-invasive and high-sensitivity scanning detection of MNPs in animals using ac susceptometry based on a high-T(c) superconducting quantum interference device (SQUID) is presented. The non-invasive results and biopsy results show good agreement, and two gold-standard biomedicine methods, Prussian blue stain and inductively coupled plasma, prove the magnetic results. This confirms that the future clinical diagnosis of bio-functional MNPs could be operated by using scanning SQUID biosusceptometry as conveniently as an ultrasonic probe.

A 3D Chemically Modified Graphene Hydrogel for Fast, Highly Sensitive, and Selective Gas Sensor.

PubMed

Wu, Jin; Tao, Kai; Guo, Yuanyuan; Li, Zhong; Wang, Xiaotian; Luo, Zhongzhen; Feng, Shuanglong; Du, Chunlei; Chen, Di; Miao, Jianmin; Norford, Leslie K

2017-03-01

Reduced graphene oxide (RGO) has proved to be a promising candidate in high-performance gas sensing in ambient conditions. However, trace detection of different kinds of gases with simultaneously high sensitivity and selectivity is challenging. Here, a chemiresistor-type sensor based on 3D sulfonated RGO hydrogel (S-RGOH) is reported, which can detect a variety of important gases with high sensitivity, boosted selectivity, fast response, and good reversibility. The NaHSO 3 functionalized RGOH displays remarkable 118.6 and 58.9 times higher responses to NO 2 and NH 3 , respectively, compared with its unmodified RGOH counterpart. In addition, the S-RGOH sensor is highly responsive to volatile organic compounds. More importantly, the characteristic patterns on the linearly fitted response-temperature curves are employed to distinguish various gases for the first time. The temperature of the sensor is elevated rapidly by an imbedded microheater with little power consumption. The 3D S-RGOH is characterized and the sensing mechanisms are proposed. This work gains new insights into boosting the sensitivity of detecting various gases by combining chemical modification and 3D structural engineering of RGO, and improving the selectivity of gas sensing by employing temperature dependent response characteristics of RGO for different gases.

Identifying sensitive ranges in global warming precipitation change dependence on convective parameters

DOE PAGES

Bernstein, Diana N.; Neelin, J. David

2016-04-28

A branch-run perturbed-physics ensemble in the Community Earth System Model estimates impacts of parameters in the deep convection scheme on current hydroclimate and on end-of-century precipitation change projections under global warming. Regional precipitation change patterns prove highly sensitive to these parameters, especially in the tropics with local changes exceeding 3mm/d, comparable to the magnitude of the predicted change and to differences in global warming predictions among the Coupled Model Intercomparison Project phase 5 models. This sensitivity is distributed nonlinearly across the feasible parameter range, notably in the low-entrainment range of the parameter for turbulent entrainment in the deep convection scheme.more » This suggests that a useful target for parameter sensitivity studies is to identify such disproportionately sensitive dangerous ranges. Here, the low-entrainment range is used to illustrate the reduction in global warming regional precipitation sensitivity that could occur if this dangerous range can be excluded based on evidence from current climate.« less

Identifying sensitive ranges in global warming precipitation change dependence on convective parameters

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernstein, Diana N.; Neelin, J. David

A branch-run perturbed-physics ensemble in the Community Earth System Model estimates impacts of parameters in the deep convection scheme on current hydroclimate and on end-of-century precipitation change projections under global warming. Regional precipitation change patterns prove highly sensitive to these parameters, especially in the tropics with local changes exceeding 3mm/d, comparable to the magnitude of the predicted change and to differences in global warming predictions among the Coupled Model Intercomparison Project phase 5 models. This sensitivity is distributed nonlinearly across the feasible parameter range, notably in the low-entrainment range of the parameter for turbulent entrainment in the deep convection scheme.more » This suggests that a useful target for parameter sensitivity studies is to identify such disproportionately sensitive dangerous ranges. Here, the low-entrainment range is used to illustrate the reduction in global warming regional precipitation sensitivity that could occur if this dangerous range can be excluded based on evidence from current climate.« less

Toxoplasmosis masking non-Hodgkin's lymphoma: a case report.

PubMed

Mighell, A; Carton, A; Carey, P; High, A

1995-12-01

A 39-year-old female with persistent cervical lymphadenopathy is reported. Initial investigations resulted in a diagnosis of toxoplasmosis, but subsequently the patient proved to have high grade immunoblastic non-Hodgkin's lymphoma. This paper highlights the difficulties in accurately diagnosing some cases of either toxoplasmosis or lymphoma, and briefly mentions some of the ongoing technical advances which will increase diagnostic specificity and sensitivity by early detection of genetic mutations.

Comparison between two methodologies for urban drainage decision aid.

PubMed

Moura, P M; Baptista, M B; Barraud, S

2006-01-01

The objective of the present work is to compare two methodologies based on multicriteria analysis for the evaluation of stormwater systems. The first methodology was developed in Brazil and is based on performance-cost analysis, the second one is ELECTRE III. Both methodologies were applied to a case study. Sensitivity and robustness analyses were then carried out. These analyses demonstrate that both methodologies have equivalent results, and present low sensitivity and high robustness. These results prove that the Brazilian methodology is consistent and can be used safely in order to select a good solution or a small set of good solutions that could be compared with more detailed methods afterwards.

Novel railway-subgrade vibration monitoring technology using phase-sensitive OTDR

NASA Astrophysics Data System (ADS)

Wang, Zhaoyong; Lu, Bin; Zheng, Hanrong; Ye, Qing; Pan, Zhengqing; Cai, Haiwen; Qu, Ronghui; Fang, Zujie; Zhao, Howell

2017-04-01

High-speed railway is being developed rapidly; its safety, including infrastructure and train operation, is vital. This paper presents a railway-subgrade vibration monitoring scheme based on phase-sensitive OTDR for railway safety. The subgrade vibration is detected and rebuilt. Multi-dimension comprehensive analysis (MDCA) is proposed to identify the running train signals and illegal constructions along railway. To our best knowledge, it is the first time that a railway-subgrade vibration monitoring scheme is proposed. This scheme is proved effective by field tests for real-time train tracking and activities monitoring along railway. It provides a new passive distributed way for all-weather railway-subgrade vibration monitoring.

Dependence of high density nitrogen-vacancy center ensemble coherence on electron irradiation doses and annealing time

NASA Astrophysics Data System (ADS)

Zhang, C.; Yuan, H.; Zhang, N.; Xu, L. X.; Li, B.; Cheng, G. D.; Wang, Y.; Gui, Q.; Fang, J. C.

2017-12-01

Negatively charged nitrogen-vacancy (NV-) center ensembles in diamond have proved to have great potential for use in highly sensitive, small-package solid-state quantum sensors. One way to improve sensitivity is to produce a high-density NV- center ensemble on a large scale with a long coherence lifetime. In this work, the NV- center ensemble is prepared in type-Ib diamond using high energy electron irradiation and annealing, and the transverse relaxation time of the ensemble—T 2—was systematically investigated as a function of the irradiation electron dose and annealing time. Dynamical decoupling sequences were used to characterize T 2. To overcome the problem of low signal-to-noise ratio in T 2 measurement, a coupled strip lines waveguide was used to synchronously manipulate NV- centers along three directions to improve fluorescence signal contrast. Finally, NV- center ensembles with a high concentration of roughly 1015 mm-3 were manipulated within a ~10 µs coherence time. By applying a multi-coupled strip-lines waveguide to improve the effective volume of the diamond, a sub-femtotesla sensitivity for AC field magnetometry can be achieved. The long-coherence high-density large-scale NV- center ensemble in diamond means that types of room-temperature micro-sized solid-state quantum sensors with ultra-high sensitivity can be further developed in the near future.

Automatic localization of cerebral cortical malformations using fractal analysis.

PubMed

De Luca, A; Arrigoni, F; Romaniello, R; Triulzi, F M; Peruzzo, D; Bertoldo, A

2016-08-21

Malformations of cortical development (MCDs) encompass a variety of brain disorders affecting the normal development and organization of the brain cortex. The relatively low incidence and the extreme heterogeneity of these disorders hamper the application of classical group level approaches for the detection of lesions. Here, we present a geometrical descriptor for a voxel level analysis based on fractal geometry, then define two similarity measures to detect the lesions at single subject level. The pipeline was applied to 15 normal children and nine pediatric patients affected by MCDs following two criteria, maximum accuracy (WACC) and minimization of false positives (FPR), and proved that our lesion detection algorithm is able to detect and locate abnormalities of the brain cortex with high specificity (WACC  =  85%, FPR  =  96%), sensitivity (WACC  =  83%, FPR  =  63%) and accuracy (WACC  =  85%, FPR  =  90%). The combination of global and local features proves to be effective, making the algorithm suitable for the detection of both focal and diffused malformations. Compared to other existing algorithms, this method shows higher accuracy and sensitivity.

Automatic localization of cerebral cortical malformations using fractal analysis

NASA Astrophysics Data System (ADS)

De Luca, A.; Arrigoni, F.; Romaniello, R.; Triulzi, F. M.; Peruzzo, D.; Bertoldo, A.

2016-08-01

Malformations of cortical development (MCDs) encompass a variety of brain disorders affecting the normal development and organization of the brain cortex. The relatively low incidence and the extreme heterogeneity of these disorders hamper the application of classical group level approaches for the detection of lesions. Here, we present a geometrical descriptor for a voxel level analysis based on fractal geometry, then define two similarity measures to detect the lesions at single subject level. The pipeline was applied to 15 normal children and nine pediatric patients affected by MCDs following two criteria, maximum accuracy (WACC) and minimization of false positives (FPR), and proved that our lesion detection algorithm is able to detect and locate abnormalities of the brain cortex with high specificity (WACC  =  85%, FPR  =  96%), sensitivity (WACC  =  83%, FPR  =  63%) and accuracy (WACC  =  85%, FPR  =  90%). The combination of global and local features proves to be effective, making the algorithm suitable for the detection of both focal and diffused malformations. Compared to other existing algorithms, this method shows higher accuracy and sensitivity.

A Water-Soluble Fluorescent Probe for SO2 Derivatives in Aqueous Solution and Serum Based on Phenanthroimidazole Dye.

PubMed

Zhou, Yang; Wang, Ying; Xiao, Shuzhang; He, Xiafeng; Zhang, Nuonuo; Li, Dejiang; Zheng, Kaibo

2017-05-01

A water-soluble fluorescent SO 2 derivatives probe PI-SO 2 based on a phenanthroimidazole dye, and a sensitive SO 2 recognition site, aldehyde was constructed. The probe PI-SO 2 exhibits desirable properties such as high sensitivity, high selectivity and good water-solubility. Significantly, we have demonstrated that the probe PI-SO 2 is suitable for rapidly fluorescence detecting of SO 2 derivatives in aqueous solution and serum. The application of the novel probe PI-SO 2 proved that it was not only a useful tool for the detection of SO 2 derivatives in vitro, but also a potential assay for investigating the effects of SO 2 derivatives, and demonstrating its value in practical applicationin of complex biological samples.

Semi-continuous ultrasonic sounding and changes of ultrasonic signal characteristics as a sensitive tool for the evaluation of ongoing microstructural changes of experimental mortar bars tested for their ASR potential.

PubMed

Lokajíček, T; Kuchařová, A; Petružálek, M; Šachlová, Š; Svitek, T; Přikryl, R

2016-09-01

Semi-continuous ultrasonic sounding of experimental mortar bars used in the accelerated alkali silica reactivity laboratory test (ASTM C1260) is proposed as a supplementary measurement technique providing data that are highly sensitive to minor changes in the microstructure of hardening/deteriorating concrete mixture. A newly designed, patent pending, heating chamber was constructed allowing ultrasonic sounding of mortar bars, stored in accelerating solution without necessity to remove the test specimens from the bath during the measurement. Subsequent automatic data analysis of recorded ultrasonic signals proved their high correlation to the measured length changes (expansion) and their high sensitivity to microstructural changes. The changes of P-wave velocity, and of the energy, amplitude, and frequency of ultrasonic signal, were in the range of 10-80%, compared to 0.51% change of the length. Results presented in this study thus show that ultrasonic sounding seems to be more sensitive to microstructural changes due to ongoing deterioration of concrete microstructure by alkali-silica reaction than the dimensional changes. Copyright © 2016. Published by Elsevier B.V.

The sensitivity of the sole of the foot in patients with Morbus Parkinson.

PubMed

Prätorius, B; Kimmeskamp, S; Milani, T L

2003-08-07

The sensory input of the foot has an important influence on balance. In patients with Morbus Parkinson (PD-patients) balance control is often impaired. Therefore, the aim of this study was to quantify the sensitivity of the plantar foot in PD-patients. Five sites of the plantar foot were examined in 24 PD-patients and in 20 controls using Semmes-Weinstein Monofilaments for touch pressure and a vibration-exciter (30 Hz) for vibration. The results show significantly higher thresholds in PD-patients. For each tested location (except the heel) the thresholds are at least twice as high as in controls. Moreover, this study proved the correlation between motor and somatosensory systems: the stronger the motor deficiencies in PD-patients (Unified Parkinson's Disease Rating System score) the higher the sensitivity thresholds for vibration. In conclusion, reduced sensitivity of the plantar foot may contribute to impaired balance control.

Research on High Sensitive D-Shaped FBG Hydrogen Sensors in Power Transformer Oil

PubMed Central

Luo, Ying-Ting; Wang, Hong-Bin; Ma, Guo-Ming; Song, Hong-Tu; Li, Chengrong; Jiang, Jun

2016-01-01

Dissolved hydrogen is a symbol gas decomposed by power transformer oil for electrical faults such as overheat or partial discharges. A novel D-shaped fiber Bragg grating (D-FBG) sensor is herein proposed and was fabricated with magnetron sputtering to measure the dissolved hydrogen concentration in power transformer oil in this paper. Different from the RI (refractive index)-based effect, D-FBG in this case is sensitive to curvature caused by stress from sensing coating, leading to Bragg wavelength shifts accordingly. The relationship between the D-FBG wavelength shift and dissolved hydrogen concentration in oil was measured experimentally in the laboratory. The detected sensitivity could be as high as 1.96 μL/L at every 1-pm wavelength shift. The results proved that a simple, polished FBG-based hydrogen sensor provides a linear measuring characteristic in the range of low hydrogen concentrations in transformer oil. Moreover, the stable hydrogen sensing performance was investigated by X-ray diffraction analysis. PMID:27782034

Research on High Sensitive D-Shaped FBG Hydrogen Sensors in Power Transformer Oil.

PubMed

Luo, Ying-Ting; Wang, Hong-Bin; Ma, Guo-Ming; Song, Hong-Tu; Li, Chengrong; Jiang, Jun

2016-10-04

Dissolved hydrogen is a symbol gas decomposed by power transformer oil for electrical faults such as overheat or partial discharges. A novel D-shaped fiber Bragg grating (D-FBG) sensor is herein proposed and was fabricated with magnetron sputtering to measure the dissolved hydrogen concentration in power transformer oil in this paper. Different from the RI (refractive index)-based effect, D-FBG in this case is sensitive to curvature caused by stress from sensing coating, leading to Bragg wavelength shifts accordingly. The relationship between the D-FBG wavelength shift and dissolved hydrogen concentration in oil was measured experimentally in the laboratory. The detected sensitivity could be as high as 1.96 μL/L at every 1-pm wavelength shift. The results proved that a simple, polished FBG-based hydrogen sensor provides a linear measuring characteristic in the range of low hydrogen concentrations in transformer oil. Moreover, the stable hydrogen sensing performance was investigated by X-ray diffraction analysis.

4-Hydroxyanisole: the most suitable monophenolic substrate for determining spectrophotometrically the monophenolase activity of polyphenol oxidase from fruits and vegetables.

PubMed

Espín, J C; Tudela, J; García-Cánovas, F

1998-05-15

A continuous spectrophotometric method for determining the monophenolase activity of polyphenol oxidase from several plant sources is described. This assay method is based on the coupling reaction between 3-methyl-2-benzothiazolinone hydrazone and the quinone product of the oxidation of 4-hydroxyanisole in the presence of polyphenol oxidase. 4-Hydroxyanisole proved to be the best monophenol assayed to measure the monophenolase activity of polyphenol oxidase from apple, artichoke, avocado, medlar, pear, and strawberry. Kinetic constants of 4-hydroxyanisole were compared to those of p-hydroxyphenyl propionic acid, a very sensitive monophenol previously reported to assay the monophenolase activity of polyphenol oxidase from apple, pear, and mushroom. The high values of the maximum steady state rate obtained for 4-hydroxyanisole suggest the existence of high catalytic constant toward this monophenol. These kinetic values were supported by nuclear magnetic resonance assays which predicted the highest reactivity of 4-hydroxyanisole. Therefore nuclear magnetic resonance assays proved to be a valuable and useful tool to predict the best monophenolic substrate for plant polyphenol oxidases. The 3-methyl-2-benzothiazlolinone-adduct for 4-hydroxyanisole was stable, with high molar absorptivity at the optimum pHs of the polyphenol oxidases assayed. All this together makes the use of 4-hydroxyanisol as monophenolic substrate and 3-methyl-2-benzothiazolinone as coupling reagent the most sensitive and precise assay method up to date reported in the literature to determine the monophenolas activity of polyphenol oxidase from fruits and vegetables.

Feature extraction and identification in distributed optical-fiber vibration sensing system for oil pipeline safety monitoring

NASA Astrophysics Data System (ADS)

Wu, Huijuan; Qian, Ya; Zhang, Wei; Tang, Chenghao

2017-12-01

High sensitivity of a distributed optical-fiber vibration sensing (DOVS) system based on the phase-sensitivity optical time domain reflectometry (Φ-OTDR) technology also brings in high nuisance alarm rates (NARs) in real applications. In this paper, feature extraction methods of wavelet decomposition (WD) and wavelet packet decomposition (WPD) are comparatively studied for three typical field testing signals, and an artificial neural network (ANN) is built for the event identification. The comparison results prove that the WPD performs a little better than the WD for the DOVS signal analysis and identification in oil pipeline safety monitoring. The identification rate can be improved up to 94.4%, and the nuisance alarm rate can be effectively controlled as low as 5.6% for the identification network with the wavelet packet energy distribution features.

Encapsulated Solid-Liquid Phase Change Nanoparticles as Thermal Barcodes for Highly Sensitive Detections of Multiple Lung Cancer Biomarkers

DTIC Science & Technology

2012-10-01

5e. TASK NUMBER LC90061 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES) 8. PERFORMING ORGANIZATION REPORT...transduction mechanism based on solid- liquid phase change nanoparticles works for the detection of multiple proteins. A series of metal and alloy...early stage. With the support from DOD-LCRP, we have proved the new signal transduction mechanism based on solid-liquid phase change nanoparticles works

First density profile measurements using frequency modulation of the continuous wave reflectometry on JETa)

NASA Astrophysics Data System (ADS)

Meneses, L.; Cupido, L.; Sirinelli, A.; Manso, M. E.; Jet-Efds Contributors

2008-10-01

We present the main design options and implementation of an X-mode reflectometer developed and successfully installed at JET using an innovative approach. It aims to prove the viability of measuring density profiles with high spatial and temporal resolution using broadband reflectometry operating in long and complex transmission lines. It probes the plasma with magnetic fields between 2.4 and 3.0 T using the V band [~(0-1.4)×1019 m-3]. The first experimental results show the high sensitivity of the diagnostic when measuring changes in the plasma density profile occurring ITER relevant regimes, such as ELMy H-modes. The successful demonstration of this concept motivated the upgrade of the JET frequency modulation of the continuous wave (FMCW) reflectometry diagnostic, to probe both the edge and core. This new system is essential to prove the viability of using the FMCW reflectometry technique to probe the plasma in next step devices, such as ITER, since they share the same waveguide complexity.

Sex differences in human cardiovascular stress responses: mathematical and physiological approaches

NASA Astrophysics Data System (ADS)

Anishchenko, Tatijana G.; Igosheva, N. B.; Saparin, P. I.

1993-06-01

A new quantitative electrocardiogram characteristic is introduced as a distribution entropy, normalized by the signal energy. A perspective of this parameter application as a diagnostic criterion is proved by series of test experiments. By way of comparison with traditional medico-biological characteristics the higher sensitivity and stability of this criterion is proved.

[L forms of Staphylococcus aureus. Behavior of coagulase, hemolytic and desoxyribonuclease activities and antibiotic sensitivity].

PubMed

Loschiavo, F; Giarrizzo, S

1977-01-01

L Forms derived from strains of coagulase positive Staphylococcus aureus, have, on the whole, preserved their DNAsic, haemolitic and coagulastic activities. L. forms showed high resistence to antibiotics acting on the bacterial cell-wall. The sensibility to other antibiotics was, roughly, analogous for the L forms as well as for the bacterial strains ones, with the exception of the clortetraciclin and the diidrostreptomicin, ehich proved to be comparatively more active on the L forms.

In vivo polarization dependant Second and Third harmonic generation imaging of Caenorhabditis elegans pharyngeal muscles

NASA Astrophysics Data System (ADS)

Filippidis, G.; Troulinaki, K.; Fotakis, C.; Tavernarakis, N.

2009-07-01

In this study Second and Third harmonic generation (SHG-THG) imaging measurements were performed to the pharyngeal muscles of the nematode Caenorhabditis elegans, in vivo with linearly polarized laser beam. Complementary information about the anatomy of the pharynx and the morphology of the anterior part of the worm were extracted. THG signals proved to have no dependence on incident light polarization, while SHG images are highly sensitive to the changes of the incident linearly polarized light.

Pd/Ag coated fiber Bragg grating sensor for hydrogen monitoring in power transformers.

PubMed

Ma, G M; Jiang, J; Li, C R; Song, H T; Luo, Y T; Wang, H B

2015-04-01

Compared with conventional DGA (dissolved gas analysis) method for on-line monitoring of power transformers, FBG (fiber Bragg grating) hydrogen sensor represents marked advantages over immunity to electromagnetic field, time-saving, and convenience to defect location. Thus, a novel FBG hydrogen sensor based on Pd/Ag (Palladium/Silver) along with polyimide composite film to measure dissolved hydrogen concentration in large power transformers is proposed in this article. With the help of Pd/Ag composite coating, the enhanced performance on mechanical strength and sensitivity is demonstrated, moreover, the response time and sensitivity influenced by oil temperature are solved by correction lines. Sensitivity measurement and temperature calibration of the specific hydrogen sensor have been done respectively in the lab. And experiment results show a high sensitivity of 0.055 pm/(μl/l) with instant response time about 0.4 h under the typical operating temperature of power transformers, which proves a potential utilization inside power transformers to monitor the health status by detecting the dissolved hydrogen concentration.

A highly sensitive peptide substrate for detecting two Aß-degrading enzymes: neprilysin and insulin-degrading enzyme.

PubMed

Chen, Po-Ting; Liao, Tai-Yan; Hu, Chaur-Jong; Wu, Shu-Ting; Wang, Steven S-S; Chen, Rita P-Y

2010-06-30

Neprilysin has been singled out as the most promising candidate for use in the degradation of Abeta as a therapy for Alzheimer's disease. In this study, a quenched fluorogenic peptide substrate containing the first seven residues of the Abeta peptide plus a C-terminal Cysteine residue was synthesized to detect neprilysin activity. A fluorophore was attached to the C-terminal Cysteine and its fluorescence was quenched by a quencher linked to the N-terminus of the peptide. When this peptide substrate was degraded by an endopeptidase, fluorescence was produced and proved to be a sensitive detection system for endopeptidase activity. Our results showed that this assay system was extremely sensitive to neprilysin and insulin-degrading enzyme, but insensitive, or much less sensitive, to other Abeta-degrading enzymes. As low as 0.1 nM of neprilysin and 0.2 nM of insulin-degrading enzyme can be detected. Copyright 2010 Elsevier B.V. All rights reserved.

Adaptive interference cancel filter for evoked potential using high-order cumulants.

PubMed

Lin, Bor-Shyh; Lin, Bor-Shing; Chong, Fok-Ching; Lai, Feipei

2004-01-01

This paper is to present evoked potential (EP) processing using adaptive interference cancel (AIC) filter with second and high order cumulants. In conventional ensemble averaging method, people have to conduct repetitively experiments to record the required data. Recently, the use of AIC structure with second statistics in processing EP has proved more efficiency than traditional averaging method, but it is sensitive to both of the reference signal statistics and the choice of step size. Thus, we proposed higher order statistics-based AIC method to improve these disadvantages. This study was experimented in somatosensory EP corrupted with EEG. Gradient type algorithm is used in AIC method. Comparisons with AIC filter on second, third, fourth order statistics are also presented in this paper. We observed that AIC filter with third order statistics has better convergent performance for EP processing and is not sensitive to the selection of step size and reference input.

Human NKCC2 cation–Cl– co-transporter complements lack of Vhc1 transporter in yeast vacuolar membranes.

PubMed

Petrezselyova, Silvia; Dominguez, Angel; Herynkova, Pavla; Macias, Juan F; Sychrova, Hana

2013-10-01

Cation–chloride co-transporters serve to transport Cl– and alkali metal cations. Whereas a large family of these exists in higher eukaryotes, yeasts only possess one cation–chloride co-transporter, Vhc1, localized to the vacuolar membrane. In this study, the human cation–chloride co-transporter NKCC2 complemented the phenotype of VHC1 deletion in Saccharomyces cerevisiae and its activity controlled the growth of salt-sensitive yeast cells in the presence of high KCl, NaCl and LiCl. A S. cerevisiae mutant lacking plasma-membrane alkali–metal cation exporters Nha1 and Ena1-5 and the vacuolar cation–chloride co-transporter Vhc1 is highly sensitive to increased concentrations of alkali–metal cations, and it proved to be a suitable model for characterizing the substrate specificity and transport activity of human wild-type and mutated cation–chloride co-transporters. Copyright © 2013 John Wiley & Sons, Ltd.

Assessing fitness-for-duty and predicting performance with cognitive neurophysiological measures

NASA Astrophysics Data System (ADS)

Smith, Michael E.; Gevins, Alan

2005-05-01

Progress is described in developing a novel test of neurocognitive status for fitness-for-duty testing. The Sustained Attention & Memory (SAM) test combines neurophysiologic (EEG) measures of brain activation with performance measures during a psychometric test of sustained attention and working memory, and then gauges changes in neurocognitive status relative to an individual"s normative baseline. In studies of the effects of common psychoactive substances that can affect job performance, including sedating antihistamines, caffeine, alcohol, marijuana, and prescription medications, test sensitivity was greater for the combined neurophysiological and performance measures than for task performance measures by themselves. The neurocognitive effects of overnight sleep deprivation were quite evident, and such effects predicted subsequent performance impairment on a flight simulator task. Sensitivity to diurnal circadian variations was also demonstrated. With further refinement and independent validation, the SAM Test may prove useful for assessing readiness-to-perform in high-asset personnel working in demanding, high risk situations.

Is it useful to combine sputum cytology and low-dose spiral computed tomography for early detection of lung cancer in formerly asbestos-exposed power industry workers?

PubMed Central

2014-01-01

Background Low-dose spiral computed tomography (LDSCT) in comparison to conventional chest X-ray proved to be a highly sensitive method of diagnosing early stage lung cancer. However, centrally located early stage lung tumours remain a diagnostic challenge. We determined the practicability and efficacy of early detection of lung cancer when combining LDSCT and sputum cytology. Methods Of a cohort of 4446 formerly asbestos exposed power industry workers, we examined a subgroup of 187 (4.2%) high risk participants for lung cancer at least once with both LDSCT and sputum cytology. After the examination period the participants were followed-up for more than three years. Results The examinations resulted in the diagnosis of lung cancer in 12 participants (6.4%). Six were in clinical stage I. We found 10 non-small cell lung carcinomas and one small cell lung carcinoma. Sputum specimens showed suspicious pathological findings in seven cases and in 11 cases the results of LDSCT indicated malignancies. The overall sensitivity and specificity of sputum cytology was 58.0% and 98% with positive (PPV) and negative (NPV) predictive values of 70% and 97%. For LDSCT we calculated the sensitivity and specificity of 92% and 97%. The PPV and NPV were 65% and 99% respectively. Conclusions Our results confirmed that in surveillance programmes a combination of sputum cytology and LDSCT is well feasible and accepted by the participants. Sputum examination alone is not effective enough for the detection of lung cancer, especially at early stage. Even in well- defined risk groups highly exposed to asbestos, we cannot recommend the use of combined LDSCT and sputum cytology examinations as long as no survival benefit has been proved for the combination of both methods. For ensuring low rates of false-positive and false-negative results, programme planners must closely cooperate with experienced medical practitioners and pathologists in a well-functioning interdisciplinary network. PMID:24739456

A transfer matrix approach to vibration localization in mistuned blade assemblies

NASA Technical Reports Server (NTRS)

Ottarson, Gisli; Pierre, Chritophe

1993-01-01

A study of mode localization in mistuned bladed disks is performed using transfer matrices. The transfer matrix approach yields the free response of a general, mono-coupled, perfectly cyclic assembly in closed form. A mistuned structure is represented by random transfer matrices, and the expansion of these matrices in terms of the small mistuning parameter leads to the definition of a measure of sensitivity to mistuning. An approximation of the localization factor, the spatially averaged rate of exponential attenuation per blade-disk sector, is obtained through perturbation techniques in the limits of high and low sensitivity. The methodology is applied to a common model of a bladed disk and the results verified by Monte Carlo simulations. The easily calculated sensitivity measure may prove to be a valuable design tool due to its system-independent quantification of mistuning effects such as mode localization.

Underwater audiogram of the California sea lion by the conditioned vocalization technique1

PubMed Central

Schusterman, Ronald J.; Balliet, Richard F.; Nixon, James

1972-01-01

Conditioning techniques were developed demonstrating that pure tone frequencies under water can exert nearly perfect control over the underwater click vocalizations of the California sea lion (Zalophus californianus). Conditioned vocalizations proved to be a reliable way of obtaining underwater sound detection thresholds in Zalophus at 13 different frequencies, covering a frequency range of 250 to 64,000 Hz. The audiogram generated by these threshold measurements suggests that under water, the range of maximal sensitivity for Zalophus lies between one and 28 kHz with best sensitivity at 16 kHz. Between 28 and 36 kHz there is a loss in sensitivity of 60 dB/octave. However, with relatively intense acoustic signals (> 38 dB re 1 μb underwater), Zalophus will respond to frequencies at least as high as 192 kHz. These results are compared with the underwater hearing of other marine mammals. ImagesFig. 1. PMID:5033891

Highly Functional TNTs with Superb Photocatalytic, Optical, and Electronic Performance Achieving Record PV Efficiency of 10.1% for 1D-Based DSSCs.

PubMed

Qadir, Muhammad Bilal; Li, Yuewen; Sahito, Iftikhar Ali; Arbab, Alvira Ayoub; Sun, Kyung Chul; Mengal, Naveed; Memon, Anam Ali; Jeong, Sung Hoon

2016-09-01

Different nanostructures of TiO2 play an important role in the photocatalytic and photoelectronic applications. TiO2 nanotubes (TNTs) have received increasing attention for these applications due to their unique physicochemical properties. Focusing on highly functional TNTs (HF-TNTs) for photocatalytic and photoelectronic applications, this study describes the facile hydrothermal synthesis of HF-TNTs by using commercial and cheaper materials for cost-effective manufacturing. To prove the functionality and applicability, these TNTs are used as scattering structure in dye-sensitized solar cells (DSSCs). Photocatalytic, optical, Brunauer-Emmett-Teller (BET), electrochemical impedance spectrum, incident-photon-to-current efficiency, and intensity-modulated photocurrent spectroscopy/intensity-modulated photovoltage spectroscopy characterizations are proving the functionality of HF-TNTs for DSSCs. HF-TNTs show 50% higher photocatalytic degradation rate and also 68% higher dye loading ability than conventional TNTs (C-TNTs). The DSSCs having HF-TNT and its composite-based multifunctional overlayer show effective light absorption, outstanding light scattering, lower interfacial resistance, longer electron lifetime, rapid electron transfer, and improved diffusion length, and consequently, J SC , quantum efficiency, and record photoconversion efficiency of 10.1% using commercial N-719 dye is achieved, for 1D-based DSSCs. These new and highly functional TNTs will be a concrete fundamental background toward the development of more functional applications in fuel cells, dye-sensitized solar cells, Li-ion batteries, photocatalysis process, ion-exchange/adsorption process, and photoelectrochemical devices. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Note: Dissolved hydrogen detection in power transformer oil based on chemically etched fiber Bragg grating.

PubMed

Jiang, Jun; Ma, Guo-ming; Song, Hong-tu; Zhou, Hong-yang; Li, Cheng-rong; Luo, Ying-ting; Wang, Hong-bin

2015-10-01

A fiber Bragg grating (FBG) sensor based on chemically etched cladding to detect dissolved hydrogen is proposed and studied in this paper. Low hydrogen concentration tests have been carried out in mixed gases and transformer oil to investigate the repeatability and sensitivity. Moreover, to estimate the influence of etched cladding thickness, a physical model of FBG-based hydrogen sensor is analyzed. Experimental results prove that thin cladding chemically etched by HF acid solution improves the response to hydrogen detection in oil effectively. At last, the sensitivity of FBG sensor chemically etched 16 μm could be as high as 0.060 pm/(μl/l), increased by more than 30% in comparison to un-etched FBG.

A robust multi-shot scan strategy for high-resolution diffusion weighted MRI enabled by multiplexed sensitivity-encoding (MUSE)

PubMed Central

Chen, Nan-kuei; Guidon, Arnaud; Chang, Hing-Chiu; Song, Allen W.

2013-01-01

Diffusion weighted magnetic resonance imaging (DWI) data have been mostly acquired with single-shot echo-planar imaging (EPI) to minimize motion induced artifacts. The spatial resolution, however, is inherently limited in single-shot EPI, even when the parallel imaging (usually at an acceleration factor of 2) is incorporated. Multi-shot acquisition strategies could potentially achieve higher spatial resolution and fidelity, but they are generally susceptible to motion-induced phase errors among excitations that are exacerbated by diffusion sensitizing gradients, rendering the reconstructed images unusable. It has been shown that shot-to-shot phase variations may be corrected using navigator echoes, but at the cost of imaging throughput. To address these challenges, a novel and robust multi-shot DWI technique, termed multiplexed sensitivity-encoding (MUSE), is developed here to reliably and inherently correct nonlinear shot-to-shot phase variations without the use of navigator echoes. The performance of the MUSE technique is confirmed experimentally in healthy adult volunteers on 3 Tesla MRI systems. This newly developed technique should prove highly valuable for mapping brain structures and connectivities at high spatial resolution for neuroscience studies. PMID:23370063

Comparison of the sensitivity of mass spectrometry atmospheric pressure ionization techniques in the analysis of porphyrinoids.

PubMed

Swider, Paweł; Lewtak, Jan P; Gryko, Daniel T; Danikiewicz, Witold

2013-10-01

The porphyrinoids chemistry is greatly dependent on the data obtained in mass spectrometry. For this reason, it is essential to determine the range of applicability of mass spectrometry ionization methods. In this study, the sensitivity of three different atmospheric pressure ionization techniques, electrospray ionization, atmospheric pressure chemical ionization and atmospheric pressure photoionization, was tested for several porphyrinods and their metallocomplexes. Electrospray ionization method was shown to be the best ionization technique because of its high sensitivity for derivatives of cyanocobalamin, free-base corroles and porphyrins. In the case of metallocorroles and metalloporphyrins, atmospheric pressure photoionization with dopant proved to be the most sensitive ionization method. It was also shown that for relatively acidic compounds, particularly for corroles, the negative ion mode provides better sensitivity than the positive ion mode. The results supply a lot of relevant information on the methodology of porphyrinoids analysis carried out by mass spectrometry. The information can be useful in designing future MS or liquid chromatography-MS experiments. Copyright © 2013 John Wiley & Sons, Ltd.

Highly Sensitive Electro-Optic Modulators

DOE Office of Scientific and Technical Information (OSTI.GOV)

DeVore, Peter S

2015-10-26

There are very important diagnostic and communication applications that receive faint electrical signals to be transmitted over long distances for capture. Optical links reduce bandwidth and distance restrictions of metal transmission lines; however, such signals are only weakly imprinted onto the optical carrier, resulting in low fidelity transmission. Increasing signal fidelity often necessitates insertion of radio-frequency (RF) amplifiers before the electro-optic modulator, but (especially at high frequencies) RF amplification results in large irreversible distortions. We have investigated the feasibility of a Sensitive and Linear Modulation by Optical Nonlinearity (SALMON) modulator to supersede RF-amplified modulators. SALMON uses cross-phase modulation, a manifestationmore » of the Kerr effect, to enhance the modulation depth of an RF-modulated optical wave. This ultrafast process has the potential to result in less irreversible distortions as compared to a RF-amplified modulator due to the broadband nature of the Kerr effect. Here, we prove that a SALMON modulator is a feasible alternative to an RFamplified modulator, by demonstrating a sensitivity enhancement factor greater than 20 and significantly reduced distortion.« less

[Cost-benefit analysis of the active screening of pulmonary tuberculosis in a recluse population entering prison].

PubMed

Martín, V; Domínguez, A; Alcaide, J

1997-01-01

In spanish prisons, tuberculosis is a serious problem of public health and health authorities don't take it seriously. To prove the efficiency of pulmonary tuberculosis case-finding on arrival at prison in order to get location resources in this activity. Cost-benefit analysis of a case-finding program compared with to wait for diagnostic to illness. The sensitivity of test was fixed in 80% and the specificity in 99.99%. The cost was based on market prices. Sensitivity analysis was done in every variables as well as tridimensional analysis in those one of more influence. The case-finding was efficient on prevalences of tuberculosis over 5 per mil. Its efficiency was hardly affected by discount social rates or the sensitivity of diagnostic tests. The prevalence of illness, the cost of diagnostic activities as well as the success of treatment and the specificity of diagnostic tests used had as influence on the efficiency model. The tridimensional analysis proved that the case-finding of pulmonary tuberculosis has efficiency on low prevalences (1 per thousand), provided the number of people cured is a 5% higher than the alternative one and the costs of case-finding less than 1,000 pesetas per subject. The case-finding pulmonary tuberculosis on arrival at prisons is of high efficiency. In a cost-opportunity situation (location of available resources, penitentiary and extrapenitentiary) the program is very efficacious taking into account the fact of higher prevalence of pulmonary tuberculosis in this people.

The NPP and J1 CrIS Operational High-Resolution Channel Selection for the NUCAPS algorithm: A demonstration of global applicability to meet users needs

NASA Astrophysics Data System (ADS)

Smith, J.; Gambacorta, A.; Barnet, C.; Smith, N.; Goldberg, M.; Pierce, B.; Wolf, W.; King, T.

2016-12-01

This work presents an overview of the NPP and J1 CrIS high resolution operational channel selection. Our methodology focuses on the spectral sensitivity characteristics of the available channels in order to maximize information content and spectral purity. These aspects are key to ensure accuracy in the retrieval products, particularly for trace gases. We will provide a demonstration of its global optimality by analyzing different test cases that are of particular interests to our JPSS Proving Ground and Risk Reduction user applications. A focus will be on high resolution trace gas retrieval capability in the context of the Alaska fire initiatives.

An approach to improving the signal-to-optical-noise ratio of pulsed magnetic field photonic sensors

NASA Astrophysics Data System (ADS)

Wang, Jiang-ping; Li, Yu-quan

2008-12-01

During last years, interest in pulsed magnetic field sensors has widely increased. In fact, magnetic field measurement has a critical part in various scientific and technical areas. In order to research on pulsed magnetic field characteristic and corresponding measuring and defending means, a sensor with high immunity to electrical noise, high sensitivity, high accuracy and wide dynamic range is needed. The conventional magnetic field measurement system currently use active metallic probes which can disturb the measuring magnetic field and make sensor very sensitive to electromagnetic noise. Photonic magnetic field sensor exhibit great advantages with respect to the electronic ones: a very good galvanic insulation, high sensitivity and very wide bandwidth. Photonic sensing technology is fit for demand of a measure pulsed magnetic field. A type of pulsed magnetic field photonic sensor has been designed, analyzed, and tested. The cross polarization angle in photonic sensor effect on the signal-to-optical-noise ratio is theoretically analyzed in this paper. A novel approach for improving the signal-to-optical-noise ratio of pulsed magnetic field sensors was proposed. The experiments have proved that this approach is practical. The theoretical analysis and simulation results show that the signal-to-optical-noise ratio can potentially be considerably improved by setup suitable for the cross polarization angle.

[Research on optimization of mathematical model of flow injection-hydride generation-atomic fluorescence spectrometry].

PubMed

Cui, Jian; Zhao, Xue-Hong; Wang, Yan; Xiao, Ya-Bing; Jiang, Xue-Hui; Dai, Li

2014-01-01

Flow injection-hydride generation-atomic fluorescence spectrometry was a widely used method in the industries of health, environmental, geological and metallurgical fields for the merit of high sensitivity, wide measurement range and fast analytical speed. However, optimization of this method was too difficult as there exist so many parameters affecting the sensitivity and broadening. Generally, the optimal conditions were sought through several experiments. The present paper proposed a mathematical model between the parameters and sensitivity/broadening coefficients using the law of conservation of mass according to the characteristics of hydride chemical reaction and the composition of the system, which was proved to be accurate as comparing the theoretical simulation and experimental results through the test of arsanilic acid standard solution. Finally, this paper has put a relation map between the parameters and sensitivity/broadening coefficients, and summarized that GLS volume, carrier solution flow rate and sample loop volume were the most factors affecting sensitivity and broadening coefficients. Optimizing these three factors with this relation map, the relative sensitivity was advanced by 2.9 times and relative broadening was reduced by 0.76 times. This model can provide a theoretical guidance for the optimization of the experimental conditions.

A self-mixing based ring-type fiber-optic acoustic sensor

NASA Astrophysics Data System (ADS)

Wang, Lutang; Wu, Chunxu; Fang, Nian

2014-07-01

A novel, simple fiber-optic acoustic sensor consisting of a self-mixing effect based laser source and a ring-type interferometer is presented. With weak external optical feedbacks, the acoustic wave signals can be detected by measuring the changes of oscillating frequency of the laser diode, induced by the disturbances of sensing fiber, with the ring-type interferometer. The operation principles of the sensor system are explored in-depth and the experimental researches are carried out. The acoustic wave signals produced by various actions, such as by pencil broken, mental pin free falling and PZT are detected for evaluating the sensing performances of the experimental system. The investigation items include the sensitivity as well as frequency responses of the sensor system. An experiment for the detection of corona discharges is carried out, which occur in a high-voltage environment between two parallel copper electrodes, under different humidity levels. The satisfied experimental results are obtained. These experimental results well prove that our proposed sensing system has very high sensitivity and excellent high frequency responses characteristics in the detections of weak, high-frequency acoustic wave signals.

The temperature dependance of photoinhibition in the tropical basidiomycete lichen Cora pavonia E. Fries.

PubMed

Coxson, D S

1987-09-01

The response of net photosynthesis (NP) and dark respiration to periods of high insolation exposure was examined in the tropical basidiomycete lichen Cora pavonia. Photoinhibition of NP proved quite dependant on temperature. Rates of light saturated NP were severely impaired immediately after pretreatment high light exposure at temperatures of 10, 20 and 40°C, while similar exposure at 30°C resulted in only minimal photoinhibition. Apparent quantum yield proved an even more sensitive indicator of photoinhibition, reduced in all temperature treatments, although inhibition was again greatest at low and high temperatures. Concurrent exposure to reduced O 2 tensions during high light exposure mitigated some of the deleterious effects of high light exposure at 10 and 20°C, suggesting an interaction of O 2 with the inactivation of photosynthetic function. This represents the first reported instance of light dependant chilling stress in lichens, and may be an important limitation on the distribution of this and other tropical lichen species. This narrow range of temperatures within which thalli of C. pavonia can withstand periods of high insolation exposure coincides with that faced by hydrated thalli during rare periods of high insolation exposure within the cloud/shroud zone on La Soufrière, and points to the necessity of considering periods of atypical or unusual climatic events when interpreting patterns of net photosynthetic response, both in tropical and in north temperate lichen species.

A mechanical simulator of cardiac wall kinematics.

PubMed

Cutrì, Elena; Bagnoli, Paola; Marcelli, Emanuela; Biondi, Federico; Cercenelli, Laura; Costantino, Maria Laura; Plicchi, Gianni; Fumero, Roberto

2010-01-01

Aim of this study is to develop a mechanical simulator (MS) reproducing cardiac wall kinematics [i.e., radial (R), longitudinal (L) and rotational (RT) motions] to test piezoelectric gyroscopic sensors (GS) that are able to measure cardiac torsion that has proved to be a sensitive index of cardiac performance. The MS consists of three brushless motors controlled by a dedicated software either separately or simultaneously reproducing the three main cardiac wall movements (R, L, RT) obtained by implementing different physiologic or pathologic velocity profiles derived from in vivo data. GS accuracy (max % error) was experimentally tested by connecting it to the MS driven in velocity in different working conditions [i.e., cardiac period (515-1030 ms), RT angle (4-16 degrees), GS axis inclination (0-90 degrees) with respect to the cardiac rotation axis]. The MS reproduced the tested velocity profiles well. The GS showed high accuracy in measuring both physiologic and pathologic RT velocity profiles, whereas they proved insensitive to R and L motions. GS axis inclination influenced measurements; however, it was possible to correct this taking the inclination angle cosine into account. The MS proved to be a useful tool to study cardiac wall kinematics and test GS reliability with a view to in vivo application.

Proceedings of Symposium on Analysis and Detection of Explosives (3rd) Held in Mannheim-Neuostheim (Germany, F.R.) on 10-13 July 1989

DTIC Science & Technology

1989-07-13

tetrabutylammonium hydroxide (TBAOH) regenerant. Because of the cost of TBAOH, we recently procured an autoregenerant accessory (in essence , an ion exchange system...examples of each of the above), the Al Exfinder 150, Al Model 85 explosives detecting doorway (which was not used for searching bags) and the Jasmin ...The Jasmin Simtec Exdetex 2, (which is really designed for building search) proved to have a very high sensitivity and a very low false alarm rate but

Correction of cell-induced optical aberrations in a fluorescence fluctuation microscope

PubMed Central

Leroux, Charles-Edouard; Grichine, Alexei; Wang, Irène; Delon, Antoine

2013-01-01

We describe the effect of optical aberrations on fluorescence fluctuations microscopy (FFM), when focusing through a single living cell. FFM measurements are performed in an aqueous fluorescent solution, and prove to be a highly sensitive tool to assess the optical aberrations introduced by the cell. We demonstrate an adaptive optics (AO) system to remove the aberration-related bias in the FFM measurements. Our data show that AO is not only useful when imaging deep in tissues, but also when performing FFM measurements through a single cellular layer. PMID:23939061

Boundary-layer receptivity of sound with roughness

NASA Technical Reports Server (NTRS)

Saric, William S.; Hoos, Jon A.; Radeztsky, Ronald H.

1991-01-01

An experimental study of receptivity was carried out using an acoustical disturbance in the freestream. The receptivity was enhanced by using a uniform two-dimensional roughness strip (tape). The roughness strip generated the local adjustment in the flow needed to couple the long-wavelength sound wave with the short-wavelength T-S wave. The method proved to be highly sensitive, with slight changes in the forcing frequency or in the height of the 2D roughness element having a strong effect on the amplitude of the observed T-S wave.

Synthesis and characterization of a smart contrast agent sensitive to calcium.

PubMed

Dhingra, Kirti; Maier, Martin E; Beyerlein, Michael; Angelovski, Goran; Logothetis, Nikos K

2008-08-07

A novel first-generation Ca2+ sensitive contrast agent, Gd-DOPTRA has been synthesized and characterized. The agent shows approximately 100% relaxivity enhancement upon addition of Ca2+. The agent is selective and sensitive to Ca2+ also in the presence of Mg2+ and Zn2+. The relaxivity studies carried out in physiological fluids prove the prospects of the agent for in vivo measurements.

Application of acetone acetals as water scavengers and derivatization agents prior to the gas chromatographic analysis of polar residual solvents in aqueous samples.

PubMed

van Boxtel, Niels; Wolfs, Kris; Van Schepdael, Ann; Adams, Erwin

2015-12-18

The sensitivity of gas chromatography (GC) combined with the full evaporation technique (FET) for the analysis of aqueous samples is limited due to the maximum tolerable sample volume in a headspace vial. Using an acetone acetal as water scavenger prior to FET-GC analysis proved to be a useful and versatile tool for the analysis of high boiling analytes in aqueous samples. 2,2-Dimethoxypropane (DMP) was used in this case resulting in methanol and acetone as reaction products with water. These solvents are relatively volatile and were easily removed by evaporation enabling sample enrichment leading to 10-fold improvement in sensitivity compared to the standard 10μL FET sample volumes for a selection of typical high boiling polar residual solvents in water. This could be improved even further if more sample is used. The method was applied for the determination of residual NMP in an aqueous solution of a cefotaxime analogue and proved to be considerably better than conventional static headspace (sHS) and the standard FET approach. The methodology was also applied to determine trace amounts of ethylene glycol (EG) in aqueous samples like contact lens fluids, where scavenging of the water would avoid laborious extraction prior to derivatization. During this experiment it was revealed that DMP reacts quantitatively with EG to form 2,2-dimethyl-1,3-dioxolane (2,2-DD) under the proposed reaction conditions. The relatively high volatility (bp 93°C) of 2,2-DD makes it possible to perform analysis of EG using the sHS methodology making additional derivatization reactions superfluous. Copyright © 2015 Elsevier B.V. All rights reserved.

Aqueous Black Colloids of Reticular Nanostructured Gold

NASA Astrophysics Data System (ADS)

Stanca, S. E.; Fritzsche, W.; Dellith, J.; Froehlich, F.; Undisz, A.; Deckert, V.; Krafft, C.; Popp, J.

2015-01-01

Since ancient times, noble gold has continuously contributed to several aspects of life from medicine to electronics. It perpetually reveals its new features. We report the finding of a unique form of gold, reticular nanostructured gold (RNG), as an aqueous black colloid, for which we present a one-step synthesis. The reticules consist of gold crystals that interconnect to form compact strands. RNG exhibits high conductivity and low reflection, and these features, coupled with the high specific surface area of the material, could prove valuable for applications in electronics and catalysis. Due to high absorption throughout the visible and infrared domain, RNG has the potential to be applied in the construction of sensitive solar cells or as a substrate for Raman spectroscopy.

Some probiotic characteristics of a fermented milk product based on microbiota of "Tibetan kefir grains" cultivated in Ukrainian household.

PubMed

Kukhtyn, Mykola; Vichko, Olena; Horyuk, Yulia; Shved, Olga; Novikov, Volodymyr

2018-01-01

The article describes some probiotic properties of fermented product made of natural association of Tibetan kefir grains cultivated in Ukrainian household (UTKG); also, the effect of UTKG microbiota on the growth of pathogenic microbiota and sensitivity to antibiotics was studied. It was found that the test-cultures of oppurtunistic pathogens ( Staphylococcus aureus , Bacillus mesentericus , and Mycobacterium luteum ) were sensitive; bacteriostatic zone of the test-culture ranged from 21 to 25 mm, and highly sensitive ( Proteus vulgaris and Aspergillus niger ) b acteriostatic zone exceeded 25 mm to probiotic bacteria of fermented product. UTKG microbiota is also moderately sensitive to multiple antibiotics that allows defining the obtained fermented milk product as functional with therapeutic properties. During the study of the influence of different NaCl and bile concentrations on acid-activity of UTKG it was found that active acid formation occurred at the concentrations up to 4% NaCl in cultivation medium (boiled milk) and at 20% bile and 0.45% phenol. It proves microbial association to be capable of withstanding adverse gastrointestinal conditions and continue developing.

Highly sensitive ;turn-on; fluorescent chemical sensor for trace analysis of Cr3 + using electro-synthesized poly(N-(9-fluorenylmethoxycarbonyl)-L-histidine)

NASA Astrophysics Data System (ADS)

Zhang, Hui; Zhang, Ge; Xu, Jingkun; Wen, Yangping; Ming, Shouli; Zhang, Jie; Ding, Wanchuan

2018-02-01

Trivalent chromium (Cr3 +) can cause severely environment pollution, declining quality of edible agro-products in plants and animals, and human diseases. Poly(N-(9-fluorenylmethoxycarbonyl)-L-histidine) (PFLH) synthesized by the direct electro-polymerization of its corresponding commercially available monomer in both boron trifluoride diethyl etherate and dichloromethane mixed system. The ;turn-on; type fluorescent sensor based on PFLH displayed high sensitivity and selectivity for Cr3 + detecting. The structure of PFLH was rationally proved by 1H NMR spectra, FT-IR spectra, quantum chemical calculations, and its optical properties were characterized. The electro-synthesized PFLH exhibited a ;turn-on; fluorescent response towards Cr3 +, which was employed as a sensing platform for the ;turn-on; fluorescent analysis of Cr3 + in a wide linear range from 5.1 nM to 25 μM with a low limit of detection as low as 1.7 nM. The possible mechanism of fluorescent ;turn-on; sensor based on PFLH for Cr3 + was proposed. The sensor displayed high sensitivity, good selectivity, satisfactory practicability, suggesting that PFLH has potential fluorescent application for ;turn-on; sensing Cr3 + in agricultural environments and edible agro-products of plants and animals.

Kidney paired exchange and desensitization: Strategies to transplant the difficult to match kidney patients with living donors.

PubMed

Pham, Thomas A; Lee, Jacqueline I; Melcher, Marc L

2017-01-01

With organs in short supply, only a limited number of kidney transplants can be performed a year. Live donor donation accounts for 1/3rd of all kidney transplants performed in the United States. Unfortunately, not every donor recipient pair is feasible because of Human leukocyte antigen (HLA) sensitization and ABO incompatibility. To overcome these barriers to transplant, strategies such as kidney paired donation (KPD) and desensitization have been developed. KPD is the exchange of donors between at least two incompatible donor-recipient pairs such that they are now compatible. Desensitization is the removal of circulating donor specific antibodies to prevent graft rejection. Regardless of the treatment strategy, highly sensitized patients whose calculated panel reactive antibody (cPRA) is ≥95% remain difficult to transplant with match rates as low as 15% in KPD pools. Desensitization has proved to be difficult in those with high antibody titers. A novel approach is the combination of both KPD and desensitization to facilitate compatible and successful transplantation. A highly sensitized patient can be paired with a better immunological match in the KPD pool and subsequently desensitized to a lesser degree. This article reviews the current progress in KPD and desensitization and their use as a combined therapy. Copyright © 2017 Elsevier Inc. All rights reserved.

Highly labeled methylene blue-ds DNA silica nanoparticles for signal enhancement of immunoassays: application to the sensitive detection of bacteria in human platelet concentrates.

PubMed

Bonnet, Romaric; Farre, Carole; Valera, Lionel; Vossier, Ludivine; Léon, Fanny; Dagland, Typhaine; Pouzet, Agnès; Jaffrézic-Renault, Nicole; Fareh, Jeannette; Fournier-Wirth, Chantal; Chaix, Carole

2018-05-15

A nanoparticle-based electrochemical sandwich immunoassay was developed for bacteria detection in platelet concentrates. For the assay, magnetic beads were functionalized with antibodies to allow the specific capture of bacteria from the complex matrix, and innovative methylene blue-DNA/nanoparticle assemblies provided the electrochemical response for amplified detection. This nanoparticular system was designed as a temperature-sensitive nano-tool for electrochemical detection. First, oligonucleotide-functionalized nanoparticles were obtained by direct synthesis of the DNA strands on the nanoparticle surface using an automated oligonucleotide synthesizer. Densely packed DNA coverage was thus obtained. Then, DNA duplexes were constructed on the NP surface with a complementary strand bearing a 3 methylene blue tag. This strategy ultimately produced highly functionalized nanoparticles with electrochemical markers. These assemblies enabled amplification of the electrochemical signal, resulting in a very good sensitivity. A proof-of-concept was carried out for E. coli detection in human platelet concentrates. Bacterial contamination of this complex biological matrix is the highest residual infectious risk in blood transfusion. The development of a rapid assay that could reach 10-102 CFU mL-1 sensitivity is a great challenge. The nanoparticle-based electrochemical sandwich immunoassay carried out on a boron doped diamond electrode proved to be sensitive for E. coli detection in human platelets. Two antibody pairs were used to develop either a generic assay against certain Gram negative strains or a specific assay for E. coli. The methylene blue-DNA/nanoparticles amplify sensitivity ×1000 compared with the assay run without NPs for electrochemical detection. A limit of detection of 10 CFU mL-1 in a biological matrix was achieved for E. coli using the highly specific antibody pair.

Nuclear morphology for the detection of alterations in bronchial cells from lung cancer: an attempt to improve sensitivity and specificity.

PubMed

Fafin-Lefevre, Mélanie; Morlais, Fabrice; Guittet, Lydia; Clin, Bénédicte; Launoy, Guy; Galateau-Sallé, Françoise; Plancoulaine, Benoît; Herlin, Paulette; Letourneux, Marc

2011-08-01

To identify which morphologic or densitometric parameters are modified in cell nuclei from bronchopulmonary cancer based on 18 parameters involving shape, intensity, chromatin, texture, and DNA content and develop a bronchopulmonary cancer screening method relying on analysis of sputum sample cell nuclei. A total of 25 sputum samples from controls and 22 bronchial aspiration samples from patients presenting with bronchopulmonary cancer who were professionally exposed to cancer were used. After Feulgen staining, 18 morphologic and DNA content parameters were measured on cell nuclei, via image cytom- etry. A method was developed for analyzing distribution quantiles, compared with simply interpreting mean values, to characterize morphologic modifications in cell nuclei. Distribution analysis of parameters enabled us to distinguish 13 of 18 parameters that demonstrated significant differences between controls and cancer cases. These parameters, used alone, enabled us to distinguish two population types, with both sensitivity and specificity > 70%. Three parameters offered 100% sensitivity and specificity. When mean values offered high sensitivity and specificity, comparable or higher sensitivity and specificity values were observed for at least one of the corresponding quantiles. Analysis of modification in morphologic parameters via distribution analysis proved promising for screening bronchopulmonary cancer from sputum.

SERS strategy based on the modified Au nanoparticles for highly sensitive detection of bisphenol A residues in milk.

PubMed

Yang, Libin; Chen, Yongliang; Shen, Yu; Yang, Ming; Li, Xiuling; Han, Xiaoxia; Jiang, Xin; Zhao, Bing

2018-03-01

Bisphenol A (BPA) is a highly toxic chemical, and its residue in milk product is threatening people's health due to its possible leaching from the packagings and cans with BPA coating. In this work, halides modified Au nanoparticles (NPs) as the modification substrates were first designed for rapid and sensitive determination of BPA residue in real milk by SERS method with the assistance of aggregation agents (Zn 2+ ). It can be concluded that Au NPs modification substrate with assistance of the aggregation agent can remarkably improve the detection sensitivity of BPA residue, which can significantly enhance the SERS signal of BPA and achieve the trace-level detection of BPA residue. Under the optimal conditions, the limit of detection of BPA residue can be as low as to 4.3 × 10 -9 mol/L (equal to 0.98 × 10 -3 mg/kg), which is much less than the standard of European Union (0.6mg/kg). And, there is a good linear relationship (R 2 = 0.990) between the intensity of SERS signal and the logarithm of BPA concentration in the range of 1.0 × 10 -8 -1.0 × 10 -3 mol/L. By this method, the recovery of BPA residue ranges from 89.5% to 100.2% with relative standard deviation between 4.6% and 2.7%. The proposed SERS method proves to be reliable, highly sensitive and possesses good reproducibility, which is very promising for sensitive detection of bisphenols residue in foodstuff. Copyright © 2017 Elsevier B.V. All rights reserved.

Sensitive analytical method for simultaneous analysis of some vasoconstrictors with highly overlapped analytical signals

NASA Astrophysics Data System (ADS)

Nikolić, G. S.; Žerajić, S.; Cakić, M.

2011-10-01

Multivariate calibration method is a powerful mathematical tool that can be applied in analytical chemistry when the analytical signals are highly overlapped. The method with regression by partial least squares is proposed for the simultaneous spectrophotometric determination of adrenergic vasoconstrictors in decongestive solution containing two active components: phenyleprine hydrochloride and trimazoline hydrochloride. These sympathomimetic agents are that frequently associated in pharmaceutical formulations against the common cold. The proposed method, which is, simple and rapid, offers the advantages of sensitivity and wide range of determinations without the need for extraction of the vasoconstrictors. In order to minimize the optimal factors necessary to obtain the calibration matrix by multivariate calibration, different parameters were evaluated. The adequate selection of the spectral regions proved to be important on the number of factors. In order to simultaneously quantify both hydrochlorides among excipients, the spectral region between 250 and 290 nm was selected. A recovery for the vasoconstrictor was 98-101%. The developed method was applied to assay of two decongestive pharmaceutical preparations.

Electrostatic Effects in Filamentous Protein Aggregation

PubMed Central

Buell, Alexander K.; Hung, Peter; Salvatella, Xavier; Welland, Mark E.; Dobson, Christopher M.; Knowles, Tuomas P.J.

2013-01-01

Electrostatic forces play a key role in mediating interactions between proteins. However, gaining quantitative insights into the complex effects of electrostatics on protein behavior has proved challenging, due to the wide palette of scenarios through which both cations and anions can interact with polypeptide molecules in a specific manner or can result in screening in solution. In this article, we have used a variety of biophysical methods to probe the steady-state kinetics of fibrillar protein self-assembly in a highly quantitative manner to detect how it is modulated by changes in solution ionic strength. Due to the exponential modulation of the reaction rate by electrostatic forces, this reaction represents an exquisitely sensitive probe of these effects in protein-protein interactions. Our approach, which involves a combination of experimental kinetic measurements and theoretical analysis, reveals a hierarchy of electrostatic effects that control protein aggregation. Furthermore, our results provide a highly sensitive method for the estimation of the magnitude of binding of a variety of ions to protein molecules. PMID:23473495

Objectification of steering feel around straight-line driving for vehicle/tyre design

NASA Astrophysics Data System (ADS)

Kim, Jungsik; Yoon, Yong-San

2015-02-01

This paper presents the objectification techniques for the assessment of steering feel including {on-centre} feel and steering response by measurement data. Here, new objective parameters are developed by considering not only the process by which the steering feel is evaluated subjectively but also by the ergonomic perceptive sensitivity of the driver. In order to validate such objective parameters, subjective tests are carried out by professional drivers. Objective measurements are also performed for several cars at a proving ground. The linear correlation coefficients between the subjective ratings and the objective parameters are calculated. As one of new objective parameters, steering wheel angle defined by ergonomic perception sensitivity shows high correlation with the subjective questionnaires of on-center responses. Newly defined steering torque curvature also shows high correlation with the subjective questionnaires of on-center effort. These correlation results conclude that the subjective assessment of steering feel can be successfully explained and objectified by means of the suggested objective parameters.

HPV DNA target hybridization concentrations studies using interdigitated electrodes (IDE) for early detection of cervical cancer

NASA Astrophysics Data System (ADS)

Noriani, C.; Hashim, U.; Azizah, N.; Nadzirah, Sh.; Arshad, M. K. Md; Ruslinda, A. R.; Gopinath, Subash C. B.

2017-03-01

Human Papillomaviruses (HPV) is the major cause of cervical cancer. HPV 16 and HPV 18 are the two types of HPV are the most HPV-associated cancers and responsible as a high-risk HPV. Cervical cancer took about 70 percent of all cases due to HPV infections. Cervical cancer mostly growth on a woman's cervix and its was developed slowly as cancer. TiO2 particles give better performance and low cost of the biosensor. The used of 3-aminopropyl triethoxysilane (APTES) will be more efficient for DNA nanochip. APTES used as absorption reaction to immobilize organic biomolecules on the inorganic surface. Furthermore, APTES provide better functionalization of the adsorption mechanism on IDE. The surface functionalized for immobilizing the DNA, which is the combination of the DNA probe and the HPV target produces high sensitivity and speed detection of the IDE. The Current-Voltage (IV) characteristic proved the sensitivity of the DNA nanochip increase as the concentration varied from 0% concentration to 24% of APTES concentration.

Hydrogen bubble dynamic template fabrication of nanoporous Cu film supported by graphene nanaosheets: A highly sensitive sensor for detection of nitrite.

PubMed

Majidi, Mir Reza; Ghaderi, Seyran

2017-12-01

High surface area nanoporous Cu film (NPCF) has been successfully synthesized using a hydrogen bubble dynamic template on the graphene nanosheets (GNs) modified glassy carbon electrode (GCE). The effect of different synthesis conditions such as applied potential and deposition time on the NPCF morphology was investigated. The structure and constituent of the NPCF-GNs/GCE were characterized by scanning electron microscopy (SEM), energy-dispersive x-ray (EDX), X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS) and electrochemical methods. The study on electrocatalytic performance of the NPCF-GNs/GCE demonstrated that this electrode has excellent catalytic activity toward nitrite oxidation. The quantitative measurement of nitrite by amperometric method showed a wide concentration range (0.1-100µmolL -1 ) with a detection limit and a sensitivity of 8.87 × 10 -8 molL -1 and 3.1 AL/molcm 2 , respectively. The excellent electrochemical response and high sensitivity of the proposed electrode were attributed to the 3D structure of NPCF and the synergic effect of NPCF and GNs. Furthermore, this electrode showed some other advantages including good repeatability, high reproducibility, long-term stability and anti-interference performance toward nitrite sensing. The applicability of the proposed electrode was proved by successful determination of nitrite in real samples (tap water, river water and sausage samples). Copyright © 2017 Elsevier B.V. All rights reserved.

Design of efficient, broadband single-element (20-80 MHz) ultrasonic transducers for medical imaging applications.

PubMed

Cannata, Jonathan M; Ritter, Timothy A; Chen, Wo-Hsing; Silverman, Ronald H; Shung, K Kirk

2003-11-01

This paper discusses the design, fabrication, and testing of sensitive broadband lithium niobate (LiNbO3) single-element ultrasonic transducers in the 20-80 MHz frequency range. Transducers of varying dimensions were built for an f# range of 2.0-3.1. The desired focal depths were achieved by either casting an acoustic lens on the transducer face or press-focusing the piezoelectric into a spherical curvature. For designs that required electrical impedance matching, a low impedance transmission line coaxial cable was used. All transducers were tested in a pulse-echo arrangement, whereby the center frequency, bandwidth, insertion loss, and focal depth were measured. Several transducers were fabricated with center frequencies in the 20-80 MHz range with the measured -6 dB bandwidths and two-way insertion loss values ranging from 57 to 74% and 9.6 to 21.3 dB, respectively. Both transducer focusing techniques proved successful in producing highly sensitive, high-frequency, single-element, ultrasonic-imaging transducers. In vivo and in vitro ultrasonic backscatter microscope (UBM) images of human eyes were obtained with the 50 MHz transducers. The high sensitivity of these devices could possibly allow for an increase in depth of penetration, higher image signal-to-noise ratio (SNR), and improved image contrast at high frequencies when compared to previously reported results.

Large voltage modulation in superconducting quantum interference devices with submicron-scale step-edge junctions

NASA Astrophysics Data System (ADS)

Lam, Simon K. H.

2017-09-01

A promising direction to improve the sensitivity of a SQUID is to increase its junction's normal resistance value, Rn, as the SQUID modulation voltage scales linearly with Rn. As a first step to develop highly sensitive single layer SQUID, submicron scale YBCO grain boundary step edge junctions and SQUIDs with large Rn were fabricated and studied. The step-edge junctions were reduced to submicron scale to increase their Rn values using focus ion beam, FIB and the measurement of transport properties were performed from 4.3 to 77 K. The FIB induced deposition layer proves to be effective to minimize the Ga ion contamination during the FIB milling process. The critical current-normal resistance value of submicron junction at 4.3 K was found to be 1-3 mV, comparable to the value of the same type of junction in micron scale. The submicron junction Rn value is in the range of 35-100 Ω, resulting a large SQUID modulation voltage in a wide temperature range. This performance promotes further investigation of cryogen-free, high field sensitivity SQUID applications at medium low temperature, e.g. at 40-60 K.

Burn depth determination using high-speed polarization-sensitive Mueller optical coherence tomography with continuous polarization modulation

NASA Astrophysics Data System (ADS)

Todorović, Miloš; Ai, Jun; Pereda Cubian, David; Stoica, George; Wang, Lihong

2006-02-01

National Health Interview Survey (NHIS) estimates more than 1.1 million burn injuries per year in the United States, with nearly 15,000 fatalities from wounds and related complications. An imaging modality capable of evaluating burn depths non-invasively is the polarization-sensitive optical coherence tomography. We report on the use of a high-speed, fiber-based Mueller-matrix OCT system with continuous source-polarization modulation for burn depth evaluation. The new system is capable of imaging at near video-quality frame rates (8 frames per second) with resolution of 10 μm in biological tissue (index of refraction: 1.4) and sensitivity of 78 dB. The sample arm optics is integrated in a hand-held probe simplifying the in vivo experiments. The applicability of the system for burn depth determination is demonstrated using biological samples of porcine tendon and porcine skin. The results show an improved imaging depth (1 mm in tendon) and a clear localization of the thermally damaged region. The burnt area determined from OCT images compares well with the histology, thus proving the system's potential for burn depth determination.

Highly efficient evaluation of a gas mixer using a hollow waveguide based laser spectral sensor

NASA Astrophysics Data System (ADS)

Du, Z.; Yang, X.; Li, J.; Yang, Y.; Qiao, C.

2017-05-01

This paper aims to provide a fast, sensitive, and accurate characterization of a Mass Flow Controller (MFC) based gas mixer. The gas mixer was evaluated by using a hollow waveguide based laser spectral sensor with high efficiency. Benefiting from the sensor's fast response, high sensitivity and continuous operation, multiple key parameters of the mixer, including mixing uncertainty, linearity, and response time, were acquired by a one-round test. The test results show that the mixer can blend multi-compound gases quite efficiently with an uncertainty of 1.44% occurring at a flow rate of 500 ml/min, with the linearity of 0.998 43 and the response time of 92.6 s. The results' reliability was confirmed by the relative measurement of gas concentration, in which the isolation of the sensor's uncertainty was conducted. The measured uncertainty has shown well coincidence with the theoretical uncertainties of the mixer, which proves the method to be a reliable characterization. Consequently, this sort of laser based characterization's wide appliance on gas analyzer's evaluations is demonstrated.

A colorimetric and fluorescent probe for detecting intracellular biothiols.

PubMed

Chen, Chunyang; Liu, Wei; Xu, Cong; Liu, Weisheng

2016-11-15

A new rapid and highly sensitive coumarin-based probe (probe 1) has been designed and synthesized for detecting intracellular thiols. Probe 1 was prepared by a 4-step procedure as a latent fluorescence probe to achieve high sensitivity and fluorescence turn-on response toward cysteine and homocysteine over GSH and other various natural amino acids under physiological conditions. Owing to specific cyclization between thiols and aldehyde group, probe 1 displayed a highly selectivity toward cysteine and homocysteine. Above all, probe 1 was successfully used for fluorescence imaging of biothiols in Hela cells, and quantitative determination had been achieved within a certain range. Then specific fluorescence imaging of mice organ tissues was obtained for proving the permeability of probe 1. Simultaneously, the viability was measured to be more than 80%, which shows probe 1 can be a rapid and biocompatible probe for biothiols in cells. Furthermore, the measurement of thiols detection in 5 kinds of animal serum showed that probe 1 can be used in determination of biothiols in blood. Copyright © 2016 Elsevier B.V. All rights reserved.

Development and validation of a high-performance liquid chromatography method for the quantification of talazoparib in rat plasma: Application to plasma protein binding studies.

PubMed

Hidau, Mahendra Kumar; Kolluru, Srikanth; Palakurthi, Srinath

2018-02-01

A sensitive and selective RP-HPLC method has been developed and validated for the quantification of a highly potent poly ADP ribose polymerase inhibitor talazoparib (TZP) in rat plasma. Chromatographic separation was performed with isocratic elution method. Absorbance for TZP was measured with a UV detector (SPD-20A UV-vis) at a λ max of 227 nm. Protein precipitation was used to extract the drug from plasma samples using methanol-acetonitrile (65:35) as the precipitating solvent. The method proved to be sensitive and reproducible over a 100-2000 ng/mL linearity range with a lower limit of quantification (LLQC) of 100 ng/mL. TZP recovery was found to be >85%. Following analytical method development and validation, it was successfully employed to determine the plasma protein binding of TZP. TZP has a high level of protein binding in rat plasma (95.76 ± 0.38%) as determined by dialysis method. Copyright © 2017 John Wiley & Sons, Ltd.

Highly efficient evaluation of a gas mixer using a hollow waveguide based laser spectral sensor.

PubMed

Du, Z; Yang, X; Li, J; Yang, Y; Qiao, C

2017-05-01

This paper aims to provide a fast, sensitive, and accurate characterization of a Mass Flow Controller (MFC) based gas mixer. The gas mixer was evaluated by using a hollow waveguide based laser spectral sensor with high efficiency. Benefiting from the sensor's fast response, high sensitivity and continuous operation, multiple key parameters of the mixer, including mixing uncertainty, linearity, and response time, were acquired by a one-round test. The test results show that the mixer can blend multi-compound gases quite efficiently with an uncertainty of 1.44% occurring at a flow rate of 500 ml/min, with the linearity of 0.998 43 and the response time of 92.6 s. The results' reliability was confirmed by the relative measurement of gas concentration, in which the isolation of the sensor's uncertainty was conducted. The measured uncertainty has shown well coincidence with the theoretical uncertainties of the mixer, which proves the method to be a reliable characterization. Consequently, this sort of laser based characterization's wide appliance on gas analyzer's evaluations is demonstrated.

Fabrication of Polymeric Antireflection Film Manufactured by Anodic Aluminum Oxide Template on Dye-Sensitized Solar Cells.

PubMed

Tsai, Jenn-Kai; Tu, Yu-Shin

2017-03-15

In this study, high energy conversion efficient dye-sensitized solar cells (DSSCs) were successfully fabricated by attaching a double anti-reflection (AR) layer, which is composed of a subwavelength moth-eye structured polymethyl methacrylate (PMMA) film and a polydimethylsiloxane (PDMS) film. An efficiency of up to 6.79% was achieved. The moth-eye structured PMMA film was fabricated by using an anodic aluminum oxide (AAO) template which is simple, low-cost and scalable. The nano-pattern of the AAO template was precisely reproduced onto the PMMA film. The photoanode was composed of Titanium dioxide (TiO₂) nanoparticles (NPs) with a diameter of 25 nm deposited on the fluorine-doped tin oxide (FTO) glass substrate and the sensitizer N3. The double AR layer was proved to effectively improve the short-circuit current density (JSC) and conversion efficiency from 14.77 to 15.79 mA/cm² and from 6.26% to 6.79%, respectively.

High-Performance Piezoresistive MEMS Strain Sensor with Low Thermal Sensitivity

PubMed Central

Mohammed, Ahmed A. S.; Moussa, Walied A.; Lou, Edmond

2011-01-01

This paper presents the experimental evaluation of a new piezoresistive MEMS strain sensor. Geometric characteristics of the sensor silicon carrier have been employed to improve the sensor sensitivity. Surface features or trenches have been introduced in the vicinity of the sensing elements. These features create stress concentration regions (SCRs) and as a result, the strain/stress field was altered. The improved sensing sensitivity compensated for the signal loss. The feasibility of this methodology was proved in a previous work using Finite Element Analysis (FEA). This paper provides the experimental part of the previous study. The experiments covered a temperature range from −50 °C to +50 °C. The MEMS sensors are fabricated using five different doping concentrations. FEA is also utilized to investigate the effect of material properties and layer thickness of the bonding adhesive on the sensor response. The experimental findings are compared to the simulation results to guide selection of bonding adhesive and installation procedure. Finally, FEA was used to analyze the effect of rotational/alignment errors. PMID:22319384

Non-invasive treatment efficacy evaluation for high-intensity focused ultrasound therapy using magnetically induced magnetoacoustic measurement

NASA Astrophysics Data System (ADS)

Guo, Gepu; Wang, Jiawei; Ma, Qingyu; Tu, Juan; Zhang, Dong

2018-04-01

Although the application of high intensity focused ultrasound (HIFU) has been demonstrated to be a non-invasive treatment technology for tumor therapy, the real-time temperature monitoring is still a key issue in the practical application. Based on the temperature-impedance relation, a fixed-point magnetically induced magnetoacoustic measurement technology of treatment efficacy evaluation for tissue thermocoagulation during HIFU therapy is developed with a sensitive indicator of critical temperature monitoring in this study. With the acoustic excitation of a focused transducer in the magnetoacoustic tomography with the magnetic induction system, the distributions of acoustic pressure, temperature, electrical conductivity, and acoustic source strength in the focal region are simulated, and the treatment time dependences of the peak amplitude and the corresponding amplitude derivative under various acoustic powers are also achieved. It is proved that the strength peak of acoustic sources is generated by tissue thermocoagulation with a sharp conductivity variation. The peak amplitude of the transducer collected magnetoacoustic signal increases accordingly along with the increase in the treatment time under a fixed acoustic power. When the temperature in the range with the radial and axial widths of about ±0.46 mm and ±2.2 mm reaches 69 °C, an obvious peak of the amplitude derivative can be achieved and used as a sensitive indicator of the critical status of treatment efficacy. The favorable results prove the feasibility of real-time non-invasive temperature monitoring and treatment efficacy evaluation for HIFU ablation using the magnetically induced magnetoacoustic measurement, and might provide a new strategy for accurate dose control during HIFU therapy.

Automated Cancer Registry Notifications: Validation of a Medical Text Analytics System for Identifying Patients with Cancer from a State-Wide Pathology Repository

PubMed Central

Nguyen, Anthony N; Moore, Julie; O'Dwyer, John; Philpot, Shoni

2016-01-01

The paper assesses the utility of Medtex on automating Cancer Registry notifications from narrative histology and cytology reports from the Queensland state-wide pathology information system. A corpus of 45.3 million pathology HL7 messages (including 119,581 histology and cytology reports) from a Queensland pathology repository for the year of 2009 was analysed by Medtex for cancer notification. Reports analysed by Medtex were consolidated at a patient level and compared against patients with notifiable cancers from the Queensland Oncology Repository (QOR). A stratified random sample of 1,000 patients was manually reviewed by a cancer clinical coder to analyse agreements and discrepancies. Sensitivity of 96.5% (95% confidence interval: 94.5-97.8%), specificity of 96.5% (95.3-97.4%) and positive predictive value of 83.7% (79.6-86.8%) were achieved for identifying cancer notifiable patients. Medtex achieved high sensitivity and specificity across the breadth of cancers, report types, pathology laboratories and pathologists throughout the State of Queensland. The high sensitivity also resulted in the identification of cancer patients that were not found in the QOR. High sensitivity was at the expense of positive predictive value; however, these cases may be considered as lower priority to Cancer Registries as they can be quickly reviewed. Error analysis revealed that system errors tended to be tumour stream dependent. Medtex is proving to be a promising medical text analytic system. High value cancer information can be generated through intelligent data classification and extraction on large volumes of unstructured pathology reports. PMID:28269893

Automated Cancer Registry Notifications: Validation of a Medical Text Analytics System for Identifying Patients with Cancer from a State-Wide Pathology Repository.

PubMed

Nguyen, Anthony N; Moore, Julie; O'Dwyer, John; Philpot, Shoni

2016-01-01

The paper assesses the utility of Medtex on automating Cancer Registry notifications from narrative histology and cytology reports from the Queensland state-wide pathology information system. A corpus of 45.3 million pathology HL7 messages (including 119,581 histology and cytology reports) from a Queensland pathology repository for the year of 2009 was analysed by Medtex for cancer notification. Reports analysed by Medtex were consolidated at a patient level and compared against patients with notifiable cancers from the Queensland Oncology Repository (QOR). A stratified random sample of 1,000 patients was manually reviewed by a cancer clinical coder to analyse agreements and discrepancies. Sensitivity of 96.5% (95% confidence interval: 94.5-97.8%), specificity of 96.5% (95.3-97.4%) and positive predictive value of 83.7% (79.6-86.8%) were achieved for identifying cancer notifiable patients. Medtex achieved high sensitivity and specificity across the breadth of cancers, report types, pathology laboratories and pathologists throughout the State of Queensland. The high sensitivity also resulted in the identification of cancer patients that were not found in the QOR. High sensitivity was at the expense of positive predictive value; however, these cases may be considered as lower priority to Cancer Registries as they can be quickly reviewed. Error analysis revealed that system errors tended to be tumour stream dependent. Medtex is proving to be a promising medical text analytic system. High value cancer information can be generated through intelligent data classification and extraction on large volumes of unstructured pathology reports.

Dynamic analysis of Apollo-Salyut/Soyuz docking

NASA Technical Reports Server (NTRS)

Schliesing, J. A.

1972-01-01

The use of a docking-system computer program in analyzing the dynamic environment produced by two impacting spacecraft and the attitude control systems is discussed. Performance studies were conducted to determine the mechanism load and capture sensitivity to parametric changes in the initial impact conditions. As indicated by the studies, capture latching is most sensitive to vehicle angular-alinement errors and is least sensitive to lateral-miss error. As proved by load-sensitivity studies, peak loads acting on the Apollo spacecraft are considerably lower than the Apollo design-limit loads.

Physical cryptographic verification of nuclear warheads

PubMed Central

Kemp, R. Scott; Danagoulian, Areg; Macdonald, Ruaridh R.; Vavrek, Jayson R.

2016-01-01

How does one prove a claim about a highly sensitive object such as a nuclear weapon without revealing information about the object? This paradox has challenged nuclear arms control for more than five decades. We present a mechanism in the form of an interactive proof system that can validate the structure and composition of an object, such as a nuclear warhead, to arbitrary precision without revealing either its structure or composition. We introduce a tomographic method that simultaneously resolves both the geometric and isotopic makeup of an object. We also introduce a method of protecting information using a provably secure cryptographic hash that does not rely on electronics or software. These techniques, when combined with a suitable protocol, constitute an interactive proof system that could reject hoax items and clear authentic warheads with excellent sensitivity in reasonably short measurement times. PMID:27432959

Development of a highly sensitive screen for influenza A in guano and its application in the search for ancient RNA preserved under Antarctic Adelie penguin colonies.

PubMed

Briggs, L C; Ashton, R M; Metcalf, P

2003-01-01

We have developed a reverse transcriptase polymerase chain reaction (RT-PCR)-based assay to detect influenza A in guano samples as part of our program to investigate ancient viral RNA from under Antarctic Adelie penguin (Pygoscelis adeliae) colonies. Of five extraction protocols tested (RNeasy, GTC TRIZOL, GTC Silica, Rnaid, and AGPC), AGPC proved to be the most consistent and sensitive to low concentrations of influenza, but further purification with commercial viral nucleic acid spin filter system was still required to remove remaining PCR inhibitors. RT-PCR was then performed on the eluent and 650 bases of the M1 gene were amplified. The assay was found to be able to detect as little as 100 microl of 0.1 hemagglutination units (HU)/ml influenza.

Physical cryptographic verification of nuclear warheads

NASA Astrophysics Data System (ADS)

Kemp, R. Scott; Danagoulian, Areg; Macdonald, Ruaridh R.; Vavrek, Jayson R.

2016-08-01

How does one prove a claim about a highly sensitive object such as a nuclear weapon without revealing information about the object? This paradox has challenged nuclear arms control for more than five decades. We present a mechanism in the form of an interactive proof system that can validate the structure and composition of an object, such as a nuclear warhead, to arbitrary precision without revealing either its structure or composition. We introduce a tomographic method that simultaneously resolves both the geometric and isotopic makeup of an object. We also introduce a method of protecting information using a provably secure cryptographic hash that does not rely on electronics or software. These techniques, when combined with a suitable protocol, constitute an interactive proof system that could reject hoax items and clear authentic warheads with excellent sensitivity in reasonably short measurement times.

Physical cryptographic verification of nuclear warheads.

PubMed

Kemp, R Scott; Danagoulian, Areg; Macdonald, Ruaridh R; Vavrek, Jayson R

2016-08-02

How does one prove a claim about a highly sensitive object such as a nuclear weapon without revealing information about the object? This paradox has challenged nuclear arms control for more than five decades. We present a mechanism in the form of an interactive proof system that can validate the structure and composition of an object, such as a nuclear warhead, to arbitrary precision without revealing either its structure or composition. We introduce a tomographic method that simultaneously resolves both the geometric and isotopic makeup of an object. We also introduce a method of protecting information using a provably secure cryptographic hash that does not rely on electronics or software. These techniques, when combined with a suitable protocol, constitute an interactive proof system that could reject hoax items and clear authentic warheads with excellent sensitivity in reasonably short measurement times.

Thermo-optical characterization of fluorescent rhodamine B based temperature-sensitive nanosensors using a CMOS MEMS micro-hotplate☆

PubMed Central

Chauhan, Veeren M.; Hopper, Richard H.; Ali, Syed Z.; King, Emma M.; Udrea, Florin; Oxley, Chris H.; Aylott, Jonathan W.

2014-01-01

A custom designed microelectromechanical systems (MEMS) micro-hotplate, capable of operating at high temperatures (up to 700 °C), was used to thermo-optically characterize fluorescent temperature-sensitive nanosensors. The nanosensors, 550 nm in diameter, are composed of temperature-sensitive rhodamine B (RhB) fluorophore which was conjugated to an inert silica sol–gel matrix. Temperature-sensitive nanosensors were dispersed and dried across the surface of the MEMS micro-hotplate, which was mounted in the slide holder of a fluorescence confocal microscope. Through electrical control of the MEMS micro-hotplate, temperature induced changes in fluorescence intensity of the nanosensors was measured over a wide temperature range. The fluorescence response of all nanosensors dispersed across the surface of the MEMS device was found to decrease in an exponential manner by 94%, when the temperature was increased from 25 °C to 145 °C. The fluorescence response of all dispersed nanosensors across the whole surface of the MEMS device and individual nanosensors, using line profile analysis, were not statistically different (p < 0.05). The MEMS device used for this study could prove to be a reliable, low cost, low power and high temperature micro-hotplate for the thermo-optical characterisation of sub-micron sized particles. The temperature-sensitive nanosensors could find potential application in the measurement of temperature in biological and micro-electrical systems. PMID:25844025

Exposure Time Optimization for Highly Dynamic Star Trackers

PubMed Central

Wei, Xinguo; Tan, Wei; Li, Jian; Zhang, Guangjun

2014-01-01

Under highly dynamic conditions, the star-spots on the image sensor of a star tracker move across many pixels during the exposure time, which will reduce star detection sensitivity and increase star location errors. However, this kind of effect can be compensated well by setting an appropriate exposure time. This paper focuses on how exposure time affects the star tracker under highly dynamic conditions and how to determine the most appropriate exposure time for this case. Firstly, the effect of exposure time on star detection sensitivity is analyzed by establishing the dynamic star-spot imaging model. Then the star location error is deduced based on the error analysis of the sub-pixel centroiding algorithm. Combining these analyses, the effect of exposure time on attitude accuracy is finally determined. Some simulations are carried out to validate these effects, and the results show that there are different optimal exposure times for different angular velocities of a star tracker with a given configuration. In addition, the results of night sky experiments using a real star tracker agree with the simulation results. The summarized regularities in this paper should prove helpful in the system design and dynamic performance evaluation of the highly dynamic star trackers. PMID:24618776

How typical are 'typical' tremor characteristics? Sensitivity and specificity of five tremor phenomena.

PubMed

van der Stouwe, A M M; Elting, J W; van der Hoeven, J H; van Laar, T; Leenders, K L; Maurits, N M; Tijssen, M A J

2016-09-01

Distinguishing between different tremor disorders can be challenging. Some tremor disorders are thought to have typical tremor characteristics: the current study aims to provide sensitivity and specificity for five 'typical' tremor phenomena. Retrospectively, we examined 210 tremor patients referred for electrophysiological recordings between January 2008 and January 2014. The final clinical diagnosis was used as the gold standard. The first step was to determine whether patients met neurophysiological criteria for their type of tremor. Once established, we focused on 'typical' characteristics: tremor frequency decrease upon loading (enhanced physiological tremor (EPT)), amplitude increase upon loading, distractibility and entrainment (functional tremor (FT)), and intention tremor (essential tremor (ET)). The prevalence of these phenomena in the 'typical' group was compared to the whole group. Most patients (87%) concurred with all core clinical neurophysiological criteria for their tremor type. We found a frequency decrease upon loading to be a specific (95%), but not a sensitive (42%) test for EPT. Distractibility and entrainment both scored high on sensitivity (92%, 91%) and specificity (94%, 91%) in FT, whereas a tremor amplitude increase was specific (92%), but not sensitive (22%). Intention tremor was a specific finding in ET (85%), but not a sensitive test (45%). Combination of characteristics improved sensitivity. In this study, we retrospectively determined sensitivity and specificity for five 'typical' tremor characteristics. Characteristics proved specific, but few were sensitive. These data on tremor phenomenology will help practicing neurologists to improve distinction between different tremor disorders. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Incidence and increase in type I allergies to rubber gloves in dental medicine students].

PubMed

Heese, A; Peters, K P; Stahl, J; Koch, H U; Hornstein, O P

1995-01-01

The prevalence of type I allergy against latex was investigated in dental students by questionnaire, prick tests and the determination of specific IgE antibodies. Positive prick tests against different latex fluids were found in 18 (8.7%) of 206 students, with clinical relevance in 11 cases. When the total number of students in each semester was taken into account an increase in the minimal prevalence of clinically relevant latex allergy from 2% in the second semester to 10.4% in the tenth semester was seen. A history of glove intolerance presenting as a wheal-and-flare reaction was associated with a type I allergy against latex in only 50% of the affected subjects. Atopic diseases and hand eczema of different causes proved to be risk factors in 16 and 5 of 18 students with latex allergy, respectively. A high-ammonia accelerator-free latex fluid proved to be a very reliable test medium compared to the less sensitive determination of specific IgE antibodies to latex.

An impedimetric immunosensor for highly sensitive detection of IL-8 in human serum and saliva samples: A new surface modification method by 6-phosphonohexanoic acid for biosensing applications.

PubMed

Aydın, Elif Burcu; Sezgintürk, Mustafa Kemal

2018-08-01

In this study, we fabricated a sensitive and label-free impedimetric immunosensor based on 6-phosphonohexanoic acid (PHA) modified ITO electrode for detection of interleukin-8 (IL-8) in human serum and saliva. PHA was first employed to cancer biomarker sensing platform. Anti-IL-8 antibody was used as a biorecognition element and the detection principle of this immunosensor was based on monitoring specific interaction between anti-IL-8 antibody and IL-8 antigen. The morphological characterization of each electrode modification step was analyzed by scanning electron microscopy (SEM), SEM-energy dispersive X-ray spectroscopy (EDX) and atomic force microscopy (AFM) while electrochemical characterization was performed by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and single frequency impedance (SFI) techniques. Moreover, the antibody immobilization on the electrode surface was proved Fourier-transform infrared spectroscopy (FTIR) and Raman Spectroscopy. This proposed impedimetric immunosensor exhibited good performances with a wide linear in the range from 0.02 pg/mL to 3 pg/mL as well as a relative low detection limit of 6 fg/mL. The impedimetric immunosensor had a good specificity, stability and reproducibility. This study proved that PHA was a suitable interface material to fabricate an electrochemical biosensor. Copyright © 2018 Elsevier Inc. All rights reserved.

Determination of glyoxal and methylglyoxal in environmental and biological matrices by stir bar sorptive extraction with in-situ derivatization.

PubMed

Neng, N R; Cordeiro, C A A; Freire, A P; Nogueira, J M F

2007-10-26

Stir bar sorptive extraction with in-situ derivatization using 2,3-diaminonaphthalene (DAN) followed by liquid desorption and high performance liquid chromatography with diode array detection (SBSE(DAN)in-situ-LD-HPLC-DAD) was developed for the determination of glyoxal (Gly) and methylglyoxal (MGly) in environmental and biological matrices. DAN proved very good specificity as in-situ derivatising agent for Gly and MGly in aqueous media, allowing the formation of adducts with remarkable sensitivity, selectivity and the absence of photodegradation. Assays performed on spiked (1.0 microg L(-1)) water samples, under convenient experimental conditions, yielded recoveries of 96.2+/-7.9% for Gly and 96.1+/-6.4% for MGly. The analytical performance showed good accuracy, suitable precision (<12.0%), low detection limits (15 ng L(-1) for Gly and 25 ng L(-1) for MGly adducts) and excellent linear dynamic ranges (r2>0.99) from 0.1 to 120.0 microg L(-1). By using the standard addition method, the application of the present method to tap and swimming-pool water, beer, yeast cells suspension and urine samples allowed very good performance at the trace level. The proposed methodology proved to be a feasible alternative for routine quality control analysis, showing to be easy to implement, reliable, sensitive and with a low sample volume requirement to monitor Gly and MGly in environmental and biological matrices.

Laser confocal feedback tomography and nano-step height measurement

PubMed Central

Tan, Yidong; Wang, Weiping; Xu, Chunxin; Zhang, Shulian

2013-01-01

A promising method for tomography and step height measurement is proposed, which combines the high sensitivity of the frequency-shifted feedback laser and the axial positioning ability of confocal microscopy. By demodulating the feedback-induced intensity modulation signals, the obtained amplitude and phase information are used to respectively determine the coarse and fine measurement of the samples. Imaging the micro devices and biological samples by the demodulated amplitude, this approach is proved to be able to achieve the cross-sectional image in highly scattered mediums. And then the successful height measurement of nano-step on a glass-substrate grating by combination of both amplitude and phase information indicates its axial high resolution (better than 2 nm) in a non-ambiguous range of about ten microns. PMID:24145717

The Borderline Syndrome Index: a validation study using the personality assessment schedule.

PubMed

Marlowe, M J; O'Neill-Byrne, K; Lowe-Ponsford, F; Watson, J P

1996-01-01

This study examines the validity and screening properties of the Borderline Syndrome Index--BSI (developed in the USA) for categories of the Personality Assessment Schedule--PAS (developed in the UK). Patients were recruited by case control sampling. Chance corrected agreement between instruments and screening properties of the BSI were calculated. The BSI proved a moderately sensitive but non-specific screen. Questionnaire scores were highly correlated with symptom measures. The results do not support the validity of the BSI or its use as a screening instrument. BSI scores may be distorted by current symptoms.

Impact and vibration detection in composite materials by using intermodal interference in multimode optical fibers

NASA Astrophysics Data System (ADS)

Malki, Abdelrafik; Gafsi, Rachid; Michel, Laurent; Labarrère, Michel; Lecoy, Pierre

1996-09-01

An optical fiber sensor based on the intermodal interference principle is integrated in a composite material to detect impacts and vibrations. Six fibers are integrated at the top of a carbon/epoxy composite panel so as to form a grid into the structure. Spectral and temporal responses to impacts and acoustic vibrations of the sensor are compared with a piezoelectric accelerometer. The tests proved the facility of integration and the high sensitivity of the device. The location of impacts is performed with this arrangement by measuring the arrival times of the front waves to the fibers.

C-kit-positive gastric metastasis of lobular carcinoma of the breast masquerading as gastrointestinal stromal tumor.

PubMed

Vennapusa, Bharathi; Oman, Sarah A; Parasher, Gulshan; Cerilli, Lisa A

2010-10-01

A 61-year-old woman with no significant past history underwent gastric biopsies demonstrating a strongly c-kit-positive epithelioid malignancy, initially thought to represent gastrointestinal stromal tumor (GIST). Subsequent clinical and immunohistochemical evaluation proved the neoplasm to represent metastatic lobular carcinoma. This case illustrates that although c-kit is highly specific and sensitive for GIST, its expression may occur in a variety of other neoplasms, some of which morphologically resemble GIST and may present in the gastrointestinal tract as metastases. Therefore, a review of other c-kit-positive lesions is also highlighted.

The Focusing Optics X-ray Solar Imager

NASA Astrophysics Data System (ADS)

Glesener, Lindsay; Krucker, S.; Christe, S.; Turin, P.; McBride, S.

2009-01-01

The Focusing Optics X-ray Solar Imager (FOXSI) is a NASA Low Cost Access to Space sounding rocket payload scheduled to fly in late 2010 to observe hard X-ray emission (HXR) from the quiet Sun. Particle acceleration in small "nanoflares" in the quiet Sun is thought to play an important role in the heating of the corona to millions of degrees Kelvin. FOXSI HXR observations of these flares will provide first estimates of the non-thermal energy content in small flares from the quiet Sun. Imaging nanoflares requires high energy sensitivity and a large dynamic range. To date, the most sensitive HXR images are made using a rotating modulating collimator aboard the Reuven Ramaty High Energy Spectroscopic Imager satellite (RHESSI). However, the rotating modulation technique is intrinsically limited in sensitivity and dynamic range. The focusing optics of FOXSI will achieve a sensitivity 100 times better than that of RHESSI at energies around 10 keV. FOXSI uses nested-shell, grazing-angle optics and silicon strip detectors to achieve an angular resolution of 12" (FWHM) and 1 keV energy resolution. FOXSI will observe the quiet Sun in the 4 to 15 keV range for 5 minutes. The focusing optics technique developed by FOXSI will prove useful to future solar HXR observing missions, especially those interested in imaging faint HXR emission from particle acceleration regions in the corona.

Electrochemical Impedance Immunosensor Based on Self-Assembled Monolayers for Rapid Detection of Escherichia coli O157:H7 with Signal Amplification Using Lectin

PubMed Central

Li, Zhanming; Fu, Yingchun; Fang, Weihuan; Li, Yanbin

2015-01-01

Escherichia coli O157:H7 is a predominant foodborne pathogen with severe pathogenicity, leading to increasing attention given to rapid and sensitive detection. Herein, we propose an impedance biosensor using new kinds of screen-printed interdigitated microelectrodes (SPIMs) and wheat germ agglutinin (WGA) for signal amplification to detect E. coli O157:H7 with high sensitivity and time-efficiency. The SPIMs integrate the high sensitivity and short response time of the interdigitated electrodes and the low cost of the screen-printed electrodes. Self-assembling of bi-functional 3-dithiobis-(sulfosuccinimidyl-propionate) (DTSP) on the SPIMs was investigated and was proved to be able to improve adsorption quantity and stability of biomaterials. WGA was further adopted to enhance the signal taking advantage of the abundant lectin-binding sites on the bacteria surface. The immunosensor exhibited a detection limit of 102 cfu·mL−1, with a linear detection range from 102 to 107 cfu·mL−1 (r2 = 0.98). The total detection time was less than 1 h, showing its comparable sensitivity and rapid response. Furthermore, the low cost of one SPIM significantly reduced the detection cost of the biosensor. The biosensor may have great promise in food safety analysis and lead to a portable biosensing system for routine monitoring of foodborne pathogens. PMID:26251911

Broadband sensitized photon up-conversion at subsolar irradiance (Conference Presentation)

NASA Astrophysics Data System (ADS)

Pedrini, Jacopo; Monguzzi, Angelo; Meinardi, Francesco

2016-09-01

A crucial limit of solar devices is their inability to harvest the full solar spectrum. Currently, sensitized up-conversion based on triplet-tripled annihilation (STTA-UC) in bi-component organic systems is the most promising technique to recover sub-bandgap photons, showing good efficiencies also at excitation intensities comparable to the solar irradiance. In STTA-UC, high-energy light is generated through annihilation of metastable triplet states of molecules acting as emitters, which are populated via resonant energy transfer from a light-harvesting sensitizer. However, suitable sensitizers show narrow absorption bands, limiting the fraction of recoverable photons, therefore preventing the application of STTA-UC to real-world devices. Here we demonstrate how to overcome the described limit by using multiple sensitizers that work cooperatively to broaden the overall system absorption band. This is obtained using an additional sensitizer that transfers the extra harvested energy to the main one (sensitization of the sensitizer), or a set of properly designed complementary absorbing sensitizers all able to excite simultaneously the same emitter (multi-sensitizers). In both cases STTA-UC performances result strongly enhanced compared to the corresponding mono-sensitizer system, increasing the up-converted light intensity generated at AM 1.5 up to two times. Remarkably, by coupling our light converters to a DSSC we prove its operation by exploiting exclusively sub-bandgap photons. A detailed modeling of the photophysical processes involved in these complex systems allows us to draw the guidelines for the design of the next generation STTA-UC materials, encouraging their application to photovoltaic technologies.

Polarization sensitive localization based super-resolution microscopy with a birefringent wedge

NASA Astrophysics Data System (ADS)

Sinkó, József; Gajdos, Tamás; Czvik, Elvira; Szabó, Gábor; Erdélyi, Miklós

2017-03-01

A practical method has been presented for polarization sensitive localization based super-resolution microscopy using a birefringent dual wedge. The measurement of the polarization degree at the single molecule level can reveal the chemical and physical properties of the local environment of the fluorescent dye molecule and can hence provide information about the sub-diffraction sized structure of biological samples. Polarization sensitive STORM imaging of the F-Actins proved correlation between the orientation of fluorescent dipoles and the axis of the fibril.

Effects of atorvastatin treatment on left ventricular diastolic function in peritoneal dialysis patients-The ALEVENT clinical trial.

PubMed

Wu, Cho-Kai; Yeh, Chih-Fan; Chiang, Jiun-Yang; Lin, Ting-Tse; Wu, Yi-Fan; Chiang, Chih-Kang; Kao, Tze-Wah; Hung, Kuan-Yu; Huang, Jenq-Wen

Left ventricular diastolic dysfunction (LVDD) is common among patients undergoing peritoneal dialysis (PD). Increased levels of inflammatory biomarkers, such as high-sensitivity C-reactive protein, predict the development of LVDD. We hypothesized that PD patients with elevated high-sensitivity C-reactive protein levels might benefit from statin treatment for LVDD and designed a randomized clinical trial to prove the hypothesis. We screened 213 PD patients and randomly assigned 32 men and women with low-density lipoprotein cholesterol levels <130 mg/dL, high-sensitivity C-reactive protein levels of ≥1.5 mg/L, and LVDD, diagnosed by conventional and tissue Doppler imaging (TDI) echocardiography, to treatment with atorvastatin, 40 mg daily, or without. The primary end points were changes in TDI diastolic parameters or global strain imaging diastolic parameters. Atorvastatin reduced low-density lipoprotein cholesterol levels by 43% and high-sensitivity C-reactive protein levels by 45% (both P < .001). Follow-up TDI showed significant improvement of early mitral flow velocities divided by early diastolic peak velocities of the mitral annulus at the medial and lateral site (Nominal change for E/E medial : -5.01 ± 6.36 vs 1.80 ± 6.59 for atorvastatin and control, respectively, P = .02). There was also a significant improvement in global strain imaging after atorvastatin treatment (global strain rate, -17.12 ± 1.42 vs -14.61 ± 1.78 for atorvastatin and control, respectively, P = .002 and E/SR IVR , 462.35 ± 110.54 vs 634.09 ± 116.81, P = .003). In this trial of PD patients without hyperlipidemia but with elevated high-sensitivity C-reactive protein levels and LVDD, atorvastatin significantly improved cardiac diastolic function (ClinicalTrials.gov number, NCT01503671). Copyright © 2017. Published by Elsevier Inc.

The YORP effect on 25 143 Itokawa

NASA Astrophysics Data System (ADS)

Breiter, S.; Bartczak, P.; Czekaj, M.; Oczujda, B.; Vokrouhlický, D.

2009-11-01

Context: The asteroid 25143 Itokawa is one of the candidates for the detection of the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect in the rotation period. Previous studies were carried out up to the 196 608 facets triangulation model and were not able to provide a good theoretical estimate of this effect, raising questions about the influence of the mesh resolution and the centre of mass location on the evolution the rotation period. Aims: The YORP effect on Itokawa is computed for different topography models up to the highest resolution Gaskell mesh of 3 145 728 triangular faces in an attempt to find the best possible YORP estimate. Other, lower resolution models are also studied and the question of the dependence of the rotation period drift on the density distribution inhomogeneities is reexamined. A comparison is made with 433 Eros models possessing a similar resolution. Methods: The Rubincam approximation (zero conductivity) is assumed in the numerical simulation of the YORP effect in rotation period. The mean thermal radiation torques are summed over triangular facets assuming Keplerian heliocentric motion and uniform rotation around a body-fixed axis. Results: There is no evidence of YORP convergence in Gaskell model family. Differently simplified meshes may converge quickly to their parent models, but this does not prove the quality of YORP computed from the latter. We confirm the high sensitivity of the YORP effect to the fine details of the surface for 25 143 Itokawa and 433 Eros. The sensitivity of the Itokawa YORP to the centre of mass shift is weaker than in earlier works, but instead the results prove to be sensitive to the spin axis orientation in the body frame. Conclusions: Either the sensitivity of the YORP effect is a physical phenomenon and all present predictions are questionable, or the present thermal models are too simplified.

Beat-to-beat blood pressure analysis after premature ventricular contraction indicates sensitive baroreceptor dysfunction in Parkinson's disease.

PubMed

Haensch, Carl-Albrecht; Jörg, Johannes

2006-04-01

Extrasystoles occur in normal subjects but are significant more frequently (16.25% vs. 55%; chi(2) = 19.3; P < 0.001) seen in Parkinson's disease (PD) patients. The extrasystolic decreases in stroke volume and systolic pressure activate sympathetic vasomotor innervation and lead to a blood pressure increase for a few heartbeats. The purpose of this study was to prove whether the short time analysis of this blood pressure regulation allows the assessment of sympathetic neurocirculatory function. Records of noninvasive blood pressure monitoring were reviewed from 40 PD patients and 80 controls. A battery of cardiovascular autonomic tests, including Valsalva maneuver, tilt-table testing, echocardiography, and cardiac scintigraphy with [(123)I]meta-iodobenzylguanidine were performed. Fifty-five percent of the PD patients had at least one premature ventricular contraction (PVC) in 10 minutes lying supine at rest. After every PVC (13 PVCs) recorded from normal subjects, we found an increase in systolic blood pressure above base line with a maximum at the seventh heart beat. In all of the 22 PD patients, the systolic blood pressure was significantly decreased less than baseline in every PVC from the second to the ninth postextrasystolic beat (P < 0.001). In both groups, the extrasystolic fall in blood pressure was on average approximately 22%. The postextrasystolic potentiation did not differ (5.3% vs. 4.4%, not significant). If a PVC occurs, the analysis of short-time blood pressure regulation is a sensitive tool for baroreceptor reflex function. The advantage of this method results from the independence of patients cooperation and the high sensitivity to prove a sympathetic neurocirculatory failure within 10 heart beats. Copyright 2005 Movement Disorder Society.

Low-Cost Wireless Temperature Measurement: Design, Manufacture, and Testing of a PCB-Based Wireless Passive Temperature Sensor.

PubMed

Yan, Dan; Yang, Yong; Hong, Yingping; Liang, Ting; Yao, Zong; Chen, Xiaoyong; Xiong, Jijun

2018-02-10

Low-cost wireless temperature measurement has significant value in the food industry, logistics, agriculture, portable medical equipment, intelligent wireless health monitoring, and many areas in everyday life. A wireless passive temperature sensor based on PCB (Printed Circuit Board) materials is reported in this paper. The advantages of the sensor include simple mechanical structure, convenient processing, low-cost, and easiness in integration. The temperature-sensitive structure of the sensor is a dielectric-loaded resonant cavity, consisting of the PCB substrate. The sensitive structure also integrates a patch antenna for the transmission of temperature signals. The temperature sensing mechanism of the sensor is the dielectric constant of the PCB substrate changes with temperature, which causes the resonant frequency variation of the resonator. Then the temperature can be measured by detecting the changes in the sensor's working frequency. The PCB-based wireless passive temperature sensor prototype is prepared through theoretical design, parameter analysis, software simulation, and experimental testing. The high- and low-temperature sensing performance of the sensor is tested, respectively. The resonant frequency decreases from 2.434 GHz to 2.379 GHz as the temperature increases from -40 °C to 125 °C. The fitting curve proves that the experimental data have good linearity. Three repetitive tests proved that the sensor possess well repeatability. The average sensitivity is 347.45 KHz / ℃ from repetitive measurements conducted three times. This study demonstrates the feasibility of the PCB-based wireless passive sensor, which provides a low-cost temperature sensing solution for everyday life, modern agriculture, thriving intelligent health devices, and so on, and also enriches PCB product lines and applications.

Low-Cost Wireless Temperature Measurement: Design, Manufacture, and Testing of a PCB-Based Wireless Passive Temperature Sensor

PubMed Central

Yan, Dan; Yang, Yong; Hong, Yingping; Liang, Ting; Yao, Zong; Chen, Xiaoyong; Xiong, Jijun

2018-01-01

Low-cost wireless temperature measurement has significant value in the food industry, logistics, agriculture, portable medical equipment, intelligent wireless health monitoring, and many areas in everyday life. A wireless passive temperature sensor based on PCB (Printed Circuit Board) materials is reported in this paper. The advantages of the sensor include simple mechanical structure, convenient processing, low-cost, and easiness in integration. The temperature-sensitive structure of the sensor is a dielectric-loaded resonant cavity, consisting of the PCB substrate. The sensitive structure also integrates a patch antenna for the transmission of temperature signals. The temperature sensing mechanism of the sensor is the dielectric constant of the PCB substrate changes with temperature, which causes the resonant frequency variation of the resonator. Then the temperature can be measured by detecting the changes in the sensor’s working frequency. The PCB-based wireless passive temperature sensor prototype is prepared through theoretical design, parameter analysis, software simulation, and experimental testing. The high- and low-temperature sensing performance of the sensor is tested, respectively. The resonant frequency decreases from 2.434 GHz to 2.379 GHz as the temperature increases from −40 °C to 125 °C. The fitting curve proves that the experimental data have good linearity. Three repetitive tests proved that the sensor possess well repeatability. The average sensitivity is 347.45 KHz/°C℃ from repetitive measurements conducted three times. This study demonstrates the feasibility of the PCB-based wireless passive sensor, which provides a low-cost temperature sensing solution for everyday life, modern agriculture, thriving intelligent health devices, and so on, and also enriches PCB product lines and applications. PMID:29439393

Statistical Approach To Estimate Vaccinia-Specific Neutralizing Antibody Titers Using a High-Throughput Assay▿

PubMed Central

Kennedy, Richard; Pankratz, V. Shane; Swanson, Eric; Watson, David; Golding, Hana; Poland, Gregory A.

2009-01-01

Because of the bioterrorism threat posed by agents such as variola virus, considerable time, resources, and effort have been devoted to biodefense preparation. One avenue of this research has been the development of rapid, sensitive, high-throughput assays to validate immune responses to poxviruses. Here we describe the adaptation of a β-galactosidase reporter-based vaccinia virus neutralization assay to large-scale use in a study that included over 1,000 subjects. We also describe the statistical methods involved in analyzing the large quantity of data generated. The assay and its associated methods should prove useful tools in monitoring immune responses to next-generation smallpox vaccines, studying poxvirus immunity, and evaluating therapeutic agents such as vaccinia virus immune globulin. PMID:19535540

Robust design of microchannel cooler

NASA Astrophysics Data System (ADS)

He, Ye; Yang, Tao; Hu, Li; Li, Leimin

2005-12-01

Microchannel cooler has offered a new method for the cooling of high power diode lasers, with the advantages of small volume, high efficiency of thermal dissipation and low cost when mass-produced. In order to reduce the sensitivity of design to manufacture errors or other disturbances, Taguchi method that is one of robust design method was chosen to optimize three parameters important to the cooling performance of roof-like microchannel cooler. The hydromechanical and thermal mathematical model of varying section microchannel was calculated using finite volume method by FLUENT. A special program was written to realize the automation of the design process for improving efficiency. The optimal design is presented which compromises between optimal cooling performance and its robustness. This design method proves to be available.

Synthesis of a 68Ga-Labeled Peptoid−Peptide Hybrid for Imaging of Neurotensin Receptor Expression in Vivo

PubMed Central

2010-01-01

The neurotensin receptor subtype 1 (NTS1) represents an attractive molecular target for imaging various tumors. Positron emission tomography (PET) gained widespread importance due to its sensitivity. We combined the design of a metabolically stable neurotensin analogue with a 68Ga-radiolabeling approach. The 68Ga-labeled peptoid−peptide hybrid [68Ga]3 revealed high stability, specific tumor uptake (0.7%ID/g, 65 min p.i.), and advantageous biokinetics in vivo using HT29 tumor-bearing nude mice. Because of the ability to internalize into NTS1-expressing tumor cells, [68Ga]3 proved to be highly suitable for a reliable and practical visualization of NTS1-expressing tumors in vivo by small animal PET. PMID:24900199

Synthesis of a (68)ga-labeled peptoid-Peptide hybrid for imaging of neurotensin receptor expression in vivo.

PubMed

Maschauer, Simone; Einsiedel, Jürgen; Hocke, Carsten; Hübner, Harald; Kuwert, Torsten; Gmeiner, Peter; Prante, Olaf

2010-08-12

The neurotensin receptor subtype 1 (NTS1) represents an attractive molecular target for imaging various tumors. Positron emission tomography (PET) gained widespread importance due to its sensitivity. We combined the design of a metabolically stable neurotensin analogue with a (68)Ga-radiolabeling approach. The (68)Ga-labeled peptoid-peptide hybrid [(68)Ga]3 revealed high stability, specific tumor uptake (0.7%ID/g, 65 min p.i.), and advantageous biokinetics in vivo using HT29 tumor-bearing nude mice. Because of the ability to internalize into NTS1-expressing tumor cells, [(68)Ga]3 proved to be highly suitable for a reliable and practical visualization of NTS1-expressing tumors in vivo by small animal PET.

Weldability of high toughness Fe-12% Ni alloys containing Ti, Al or Nb

NASA Technical Reports Server (NTRS)

Devletian, J. H.; Stephens, J. R.; Witzke, W. R.

1977-01-01

Three exceptionally high-toughness Fe-12%Ni alloys designed for cryogenic service were welded using the GTA welding process. Evaluation of weldability included equivalent energy (KIed) fracture toughness tests, transverse-weld tensile tests at -196 and 25 C and weld crack sensitivity tests. The Fe-12%Ni-0.25%Ti alloy proved extremely weldable for cryogenic applications, having weld and HAZ properties comparable with those of the wrought base alloy. The Fe-12%Ni-0.5%Al had good weld properties only after the weld joint was heat treated. The Fe-12%Ni-0.25%Nb alloy was not considered weldable for cryogenic use because of its poor weld joint properties at -196 C and its susceptibility to hot cracking.

Enhanced Fano resonance in a non-adiabatic tapered fiber coupled with a microresonator.

PubMed

Zhang, Kun; Wang, Yue; Wu, Yi-Hui

2017-08-01

We achieved enhanced Fano resonance by coupling a bottle resonator with a special non-adiabatic tapered fiber, where there is a high intensity distribution ratio between high-order and fundamental modes in the tapered region, as well as single mode propagation in the waist region. The resonance line shape is theoretically proved to be related to the intensity distribution ratio of the two fiber modes and their phase shift. An enhanced Fano line shape with an extinction ratio over 15 dB is experimentally reached by improving the intensity distribution ratio and tuning the phase shift. The results can remarkably improve the sensitivity of whispering-gallery mode microresonators in the field of optical sensing.

[Micromonospora resistence to definite antibiotics and their ability to produce structurally analogous antibiotics].

PubMed

Bibikova, M V; Ivanitskaia, L P; Tikhonova, A S

1980-01-01

Thirty six cultures of Micromonospora freshly isolated from soil samples were studied with respect to their sensitivity to a number of antibiotics of various structures and modes of action. It was found that all of them were highly sensitive to penicillin, ristomycin, tetracycline, rifampicin, streptomycin, olivomycin, carminomycin and dactinomycin. Significant differences in sensitivity of the Micromonospora cultures were revealed only with respect to gentamicin, tobramicin, erythromycin and lincomycin. Seven cultures were resistant to gentamicin and tobramicin and sensitive to all of the other antibiotics. Broad spectrum antibiotics were isolated from these cultures. The study of the antibiotic chemistry showed that they were 2-desoxystreptamine-containing aminoglycosides. Two cultures proved to be resistant to erythromycin and lincomycin. When identified with the use of antibiotic resistant staphylococcal strains, the crude antibiotic substances isolated from these cultures appeared to be not active against staphylococci resistant to erythromycin and lincomycin. By their chromatograpi- behaviour the antibiotics were close to macrolides. Therefore, it was found that production of aminoglycoside and macrolide antibiotics was most characteristic of Micromonospora. A certain correlation between resistance of Micromonospora to these 2 antibiotic groups and capacity for their production was shown.

The feasibility assessment of radiation dose of movement 3D NIPAM gel by magnetic resonance imaging

NASA Astrophysics Data System (ADS)

Hsieh, Chih-Ming; Leung, Joseph Hang; Ng, Yu-Bun; Cheng, Chih-Wu; Sun, Jung-Chang; Lin, Ping-Chin; Hsieh, Bor-Tsung

2015-11-01

NIPAM dosimeter is widely accepted and recommended for its 3D distribution and accuracy in dose absorption. Up to the moment, most research works on dose measurement are based on a fixed irradiation target without the consideration of the effect from physiological motion. We present a study to construct a respiratory motion simulating patient anatomical and dosimetry model for the study of dosimetic effect of organ motion. The dose on fixed and motion targets was measured by MRI after a dose adminstration of 1, 2, 5, 8, and 10 Gy from linear accelerator. Comparison of two situations is made. The average sensitivity of fixed NIPAM was 0.1356 s-1/Gy with linearity R2=0.998. The average sensitivity of movement NIPAM was 0.1366 s-1/Gy with linearity R2=0.998 both having only 0.001 of the sensitivity difference. The difference between the two based on dose rate dependency, position and depth was not significant. There was thus no apparent impact on NIPAM dosimeter from physiological motion. The high sensitivity, linearity and stability of NIPAM dosimeter proved to be an ideal apparatus in the dose measurement in these circumstances.

An Evaluation Study of Enzyme-Linked Immunosorbent Assay (ELISA) Using Recombinant Protein Pap31 for Detection of Antibody against Bartonella bacilliformis Infection among the Peruvian Population

PubMed Central

Angkasekwinai, Nasikarn; Atkins, Erin H.; Romero, Sofia; Grieco, John; Chao, Chien Chung; Ching, Wei Mei

2014-01-01

Reliable laboratory testing is of great importance to detect Bartonella bacilliformis infection. We evaluated the sensitivity and specificity of the enzyme-linked immunosorbent assay (ELISA) using recombinant protein Pap31 (rPap31) for the detection of antibodies against B. bacilliformis as compared with immunofluorescent assay (IFA). Of the 302 sera collected between 1997 and 2000 among an at-risk Peruvian population, 103 and 34 samples tested positive for IFA-immunoglobulin G (IgG) and IFA-IgM, respectively. By using Youden's index, the cutoff values of ELISA-IgG at 0.915 gave a sensitivity of 84.5% and specificity of 94%. The cutoff values of ELISA-IgM at 0.634 gave a sensitivity of 88.2% and specificity of 85.1%. Using latent class analysis, estimates of sensitivity and specificity of almost all the assays were slightly higher than those of a conventional method of calculation. The test is proved beneficial for discriminating between infected and non-infected individuals with the advantage of low-cost and high-throughput capability. PMID:24515944

AuNPs Hybrid Black ZnO Nanorods Made by a Sol-Gel Method for Highly Sensitive Humidity Sensing

PubMed Central

Zhang, Min; Lin, Cunchong; Zhang, Jun

2018-01-01

A highly sensitive self-powered humidity sensor has been realized from AuNPs hybrid black zinc oxide (ZnO) nanorods prepared through a sol-gel method. XRD pattern reveals that both ZnO and ZnO/AuNPs exhibit a wurtzite structure. ZnO/AuNPs nanorods grow in a vertical alignment, which possesses high uniformity and forms dense arrays with a smaller diameter than that of ZnO nanoparticles. All ZnO/AuNPs and pure black ZnO show lower band gap energy than the typically reported 3.34 eV of pure ZnO. Furthermore, the band gap of ZnO/AuNPs nanocomposites is effectively influenced by the amount of AuNPs. The humidity sensing tests clearly prove that all the ZnO/AuNPs humidity sensors exhibit much higher response than that of ZnO sensors, and the sensitivity of such ZnO/AuNPs nanorods (6 mL AuNPs) display a change three orders higher than that of pure ZnO with relative humidity (RH) ranging from 11% to 95% at room temperature. The response and recovery time of the ZnO/AuNPs are 5.6 s and 32.4 s, respectively. This study of the construction of semiconductor/noble metal sensors provides a rational way to control the morphology of semiconductor nanomaterials and to design a humidity sensor with high performance. PMID:29342860

AuNPs Hybrid Black ZnO Nanorods Made by a Sol-Gel Method for Highly Sensitive Humidity Sensing.

PubMed

Zhang, Hongyan; Zhang, Min; Lin, Cunchong; Zhang, Jun

2018-01-13

A highly sensitive self-powered humidity sensor has been realized from AuNPs hybrid black zinc oxide (ZnO) nanorods prepared through a sol-gel method. XRD pattern reveals that both ZnO and ZnO/AuNPs exhibit a wurtzite structure. ZnO/AuNPs nanorods grow in a vertical alignment, which possesses high uniformity and forms dense arrays with a smaller diameter than that of ZnO nanoparticles. All ZnO/AuNPs and pure black ZnO show lower band gap energy than the typically reported 3.34 eV of pure ZnO. Furthermore, the band gap of ZnO/AuNPs nanocomposites is effectively influenced by the amount of AuNPs. The humidity sensing tests clearly prove that all the ZnO/AuNPs humidity sensors exhibit much higher response than that of ZnO sensors, and the sensitivity of such ZnO/AuNPs nanorods (6 mL AuNPs) display a change three orders higher than that of pure ZnO with relative humidity (RH) ranging from 11% to 95% at room temperature. The response and recovery time of the ZnO/AuNPs are 5.6 s and 32.4 s, respectively. This study of the construction of semiconductor/noble metal sensors provides a rational way to control the morphology of semiconductor nanomaterials and to design a humidity sensor with high performance.

An excited-state intramolecular photon transfer fluorescence probe for localizable live cell imaging of cysteine

NASA Astrophysics Data System (ADS)

Liu, Wei; Chen, Wen; Liu, Si-Jia; Jiang, Jian-Hui

2017-03-01

Small molecule probes suitable for selective and specific fluorescence imaging of some important but low-concentration intracellular reactive sulfur species such as cysteine (Cys) pose a challenge in chemical biology. We present a readily available, fast-response fluorescence probe CHCQ-Ac, with 2-(5‧-chloro-2-hydroxyl-phenyl)-6-chloro-4(3 H)-quinazolinone (CHCQ) as the fluorophore and acrylate group as the functional moiety, that enables high-selectivity and high-sensitivity for detecting Cys in both solution and biological system. After specifically reacted with Cys, the probe undergoes a seven-membered intramolecular cyclization and released the fluorophore CHCQ with excited-state intramolecular photon transfer effect. A highly fluorescent, insoluble aggregate was then formed to facilitate high-sensitivity and high-resolution imaging. The results showed that probe CHCQ-Ac affords a remarkably large Stokes shift and can detect Cys under physiological pH condition with no interference from other analytes. Moreover, this probe was proved to have excellent chemical stability, low cytotoxicity and good cell permeability. Our design of this probe provides a novel potential tool to visualize and localize cysteine in bioimaging of live cells that would greatly help to explore various Cys-related physiological and pathological cellular processes in cell biology and diagnostics.

Cost-sensitive learning for emotion robust speaker recognition.

PubMed

Li, Dongdong; Yang, Yingchun; Dai, Weihui

2014-01-01

In the field of information security, voice is one of the most important parts in biometrics. Especially, with the development of voice communication through the Internet or telephone system, huge voice data resources are accessed. In speaker recognition, voiceprint can be applied as the unique password for the user to prove his/her identity. However, speech with various emotions can cause an unacceptably high error rate and aggravate the performance of speaker recognition system. This paper deals with this problem by introducing a cost-sensitive learning technology to reweight the probability of test affective utterances in the pitch envelop level, which can enhance the robustness in emotion-dependent speaker recognition effectively. Based on that technology, a new architecture of recognition system as well as its components is proposed in this paper. The experiment conducted on the Mandarin Affective Speech Corpus shows that an improvement of 8% identification rate over the traditional speaker recognition is achieved.

Mechanical function of the heart and its alteration during myocardial ischemia and infarction. Specific reference to coronary atherosclerosis.

PubMed

Swan, H J

1979-12-01

Altered regional mechanical myocardial performance is an early, sensitive marker of myocardial ischemia, and can be estimated in man with reasonable accuracy. Identification, localization and quantification of abnormalities in mechanical performance can be used to predict the presence of coronary artery disease. Testing techniques that have little or no effect on diagnostic efficiency must be replaced with more sensitive indicators of ischemia. If experimental data are validated by findings in human subjects, accurate identification of regional wall motion changes during test conditions should prove to be a powerful marker of ischemia. To be of value, a diagnostic test must strongly increase the frequency of identification of subjects with a high probabilty for the presence of coronary artery disease in an otherwise low-prevalence population, and of those with known disease who are at the highest risk for complications including myocardial infarction or death.

Cost-Sensitive Learning for Emotion Robust Speaker Recognition

PubMed Central

Li, Dongdong; Yang, Yingchun

2014-01-01

In the field of information security, voice is one of the most important parts in biometrics. Especially, with the development of voice communication through the Internet or telephone system, huge voice data resources are accessed. In speaker recognition, voiceprint can be applied as the unique password for the user to prove his/her identity. However, speech with various emotions can cause an unacceptably high error rate and aggravate the performance of speaker recognition system. This paper deals with this problem by introducing a cost-sensitive learning technology to reweight the probability of test affective utterances in the pitch envelop level, which can enhance the robustness in emotion-dependent speaker recognition effectively. Based on that technology, a new architecture of recognition system as well as its components is proposed in this paper. The experiment conducted on the Mandarin Affective Speech Corpus shows that an improvement of 8% identification rate over the traditional speaker recognition is achieved. PMID:24999492

Terahertz absorption spectra of commonly used antimalarial drugs

NASA Astrophysics Data System (ADS)

Bawuah, Prince; Zeitler, J. Axel; Ketolainen, Jarkko; Peiponen, Kai-Erik

2018-06-01

Terahertz (THz) spectra from the pure forms [i.e. the active pharmaceutical ingredients (APIs)] of four commonly used antimalarial drugs are reported. The well-defined spectral fingerprints obtained for these APIs in the spectral range of 0.1 THz-3 THz show the sensitivity of the THz time-domain spectroscopic (THz-TDS) method for screening antimalarial drugs. For identification purpose, two commercially available antimalarial tablets were detected. Clear spectral fingerprints of the APIs in the antimalarial tablets were obtained even amidst the several types of excipients present in the tablets. This observation further proves the high sensitivity of the THz techniques in tracking the presence or absence of API in a pharmaceutical tablet. We envisage that the spectral data obtained for these drugs can contribute to a spectroscopic database in the far infrared spectral region and hence support the modelling of THz sensing to differentiate between genuine and counterfeit antimalarial tablets.

[Sensitivity of clinical Proteus strains to antibiotics and their combinations].

PubMed

Sheina, E P; Arutcheva, A A

1978-05-01

In 1976 isolation of Proteus from wounds of patients with various purulent processes amounted to 14.5 per cent. Serotypes 0-10, 0-3 and H-3 predominated among the isolates. Sensitivity of 35 clinical strains of Proteus to 10 antibiotics, furagin and nevigramone was studied by the method of serial dilutions in liquid media. All the isolates were highly resistant to the antibiotics except gentamicin, furagin and nevigramone, the MIC of which for most of the strains was 3.12, 1.6-3.12 and 6.25-12.5 gamma/ml, respectively. The effect of 14 combinations of chemotherapeutics was also studied. The combinations of gentamicin with carbenicillin, gentamicin with ampicillin and monomycin with ampicillin proved to be most effective against the Proteus strains tested. The following combinations may be of practical value: monomycin + carbenicillin, kanamycin + ampicillin, kanamycin + carbenicillin, ampicillin + furagin, gentamicin + nevigramone. The combinations of carbenicillin with furagin and gentamicin with furagin were also rational.

Using gas chromatography with ion mobility spectrometry to resolve explosive compounds in the presence of interferents.

PubMed

Cook, Greg W; LaPuma, Peter T; Hook, Gary L; Eckenrode, Brian A

2010-11-01

Ion mobility spectrometry (IMS) is a valued field detection technology because of its speed and high sensitivity, but IMS cannot easily resolve analytes of interest within mixtures. Coupling gas chromatography (GC) to IMS adds a separation capability to resolve complex matrices. A GC-IONSCAN® operated in IMS and GC⁄ IMS modes was evaluated with combinations of five explosives and four interferents. In 100 explosive/interferent combinations, IMS yielded 21 false positives while GC⁄ IMS substantially reduced the occurrence of false positives to one. In addition, the results indicate that through redesign or modification of the preconcentrator there would be significant advantages to using GC⁄ IMS, such as enhancement of the linear dynamic range (LDR) in some situations. By balancing sensitivity with LDR, GC⁄ IMS could prove to be a very advantageous tool when addressing real world complex mixture situations.

Physical cryptographic verification of nuclear warheads

DOE PAGES

Kemp, R. Scott; Danagoulian, Areg; Macdonald, Ruaridh R.; ...

2016-07-18

How does one prove a claim about a highly sensitive object such as a nuclear weapon without revealing information about the object? This paradox has challenged nuclear arms control for more than five decades. We present a mechanism in the form of an interactive proof system that can validate the structure and composition of an object, such as a nuclear warhead, to arbitrary precision without revealing either its structure or composition. We introduce a tomographic method that simultaneously resolves both the geometric and isotopic makeup of an object. We also introduce a method of protecting information using a provably securemore » cryptographic hash that does not rely on electronics or software. Finally, these techniques, when combined with a suitable protocol, constitute an interactive proof system that could reject hoax items and clear authentic warheads with excellent sensitivity in reasonably short measurement times.« less

Terahertz absorption spectra of commonly used antimalarial drugs

NASA Astrophysics Data System (ADS)

Bawuah, Prince; Zeitler, J. Axel; Ketolainen, Jarkko; Peiponen, Kai-Erik

2018-03-01

Terahertz (THz) spectra from the pure forms [i.e. the active pharmaceutical ingredients (APIs)] of four commonly used antimalarial drugs are reported. The well-defined spectral fingerprints obtained for these APIs in the spectral range of 0.1 THz-3 THz show the sensitivity of the THz time-domain spectroscopic (THz-TDS) method for screening antimalarial drugs. For identification purpose, two commercially available antimalarial tablets were detected. Clear spectral fingerprints of the APIs in the antimalarial tablets were obtained even amidst the several types of excipients present in the tablets. This observation further proves the high sensitivity of the THz techniques in tracking the presence or absence of API in a pharmaceutical tablet. We envisage that the spectral data obtained for these drugs can contribute to a spectroscopic database in the far infrared spectral region and hence support the modelling of THz sensing to differentiate between genuine and counterfeit antimalarial tablets.

Hybrid GMR Sensor Detecting 950 pT/sqrt(Hz) at 1 Hz and Room Temperature

PubMed Central

Guedes, André; Macedo, Rita; Jaramillo, Gerardo; Freitas, Paulo P.; Horsley, David A.

2018-01-01

Advances in the magnetic sensing technology have been driven by the increasing demand for the capability of measuring ultrasensitive magnetic fields. Among other emerging applications, the detection of magnetic fields in the picotesla range is crucial for biomedical applications. In this work Picosense reports a millimeter-scale, low-power hybrid magnetoresistive-piezoelectric magnetometer with subnanotesla sensitivity at low frequency. Through an innovative noise-cancelation mechanism, the 1/f noise in the MR sensors is surpassed by the mechanical modulation of the external magnetic fields in the high frequency regime. A modulation efficiency of 13% was obtained enabling a final device’s sensitivity of ~950 pT/Hz1/2 at 1 Hz. This hybrid device proved to be capable of measuring biomagnetic signals generated in the heart in an unshielded environment. This result paves the way for the development of a portable, contactless, low-cost and low-power magnetocardiography device. PMID:29509677

SWCNTs-based nanocomposites as sensitive coatings for advanced fiber optic chemical nanosensors

NASA Astrophysics Data System (ADS)

Consales, M.; Crescitelli, A.; Penza, M.; Aversa, P.; Giordano, M.; Cutolo, A.; Cusano, A.

2008-04-01

In this work, the feasibility of exploiting novel Cadmium Arachidate (CdA)/single-walled carbon nanotubes (SWCNTs) based composites as sensitive coatings for the development of robust and high performances optoelectronic chemosensors able to work in liquid environments has been investigated and proved. Here, nano-composite sensing layers have been transferred upon the distal end of standard optical fibers by the Langmuir-Blodgett (LB) technique. Reflectance measurements have been carried out to monitor ppm concentration of chemicals in water through the changes in the optical and geometrical features of the sensing overlay induced by the interaction with the analyte molecules. Preliminary experimental results evidence that such nanoscale coatings integrated with the optical fiber technology offers great potentialities for the room temperature detection of chemical traces in water and lead to significant improvements of the traditional fiber optic sensors based on SWCNTs layers.

Kinetics of thermolysis of lanthanum nitrate with hexamethylenetetramine: Crystal structure, TG-DSC, impact and friction sensitivity studies, Part-96

NASA Astrophysics Data System (ADS)

Nibha; Baranwal, B. P.; Singh, Gurdip; Singh, C. P.; Daniliuc, Constantin G.; Soni, P. K.; Nath, Yogeshwar

2014-11-01

The development of high energetic materials includes process ability and the ability to attain insensitive munitions (IM). This paper investigates the preparation of lanthanum metal nitrate complex of hexamethylenetetramine in water at room temperature. This complex of molecular formulae [La (NO3)2(H2O)6] (2HMTA) (NO3-) (H2O) was characterized by X-ray crystallography. Thermal decomposition was investigated using TG, TG-DSC and ignition delay measurements. Kinetic analysis of isothermal TG data has been investigated using model fitting methods as well as model free isoconversional methods. The sensitivity measurements towards mechanical destructive stimuli such as impact and friction were carried out and the complex was found to be insensitive. In order to identify the end product of thermolysis, X-ray diffraction patterns of end product was carried out which proves the formation of La2O3.

Suitable combination of noble/ferromagnetic metal multilayers for enhanced magneto-plasmonic biosensing.

PubMed

Regatos, David; Sepúlveda, Borja; Fariña, David; Carrascosa, Laura G; Lechuga, Laura M

2011-04-25

We present a theoretical and experimental study on the biosensing sensitivity of Au/Co/Au multilayers as transducers of the magneto-optic surface-plasmon-resonance (MOSPR) sensor. We demonstrate that the sensing response of these magneto-plasmonic (MP) transducers is a trade-off between the optical absorption and the magneto-optical activity, observing that the MP multilayer with larger MO effect does not provide the best sensing response. We show that it is possible to design highly-sensitive MP transducers able to largely surpass the limit of detection of the conventional surface-plasmon-resonance (SPR) sensor. This was proved comparing the biosensing performance of both sensors for the label-free detection of short DNA chains hybridization. For this purpose, we used and tested a novel label-free biofunctionalization protocol based on polyelectrolytes, which increases the resistance of MP transducers in aqueous environments.

Robust label-free biosensing using microdisk laser arrays with on-chip references.

PubMed

Wondimu, S F; Hippler, M; Hussal, C; Hofmann, A; Krämmer, S; Lahann, J; Kalt, H; Freude, W; Koos, C

2018-02-05

Whispering-gallery mode (WGM) microdisk lasers show great potential for highly sensitive label-free detection in large-scale sensor arrays. However, when used in practical applications under normal ambient conditions, these devices suffer from temperature fluctuations and photobleaching. Here we demonstrate that these challenges can be overcome by a novel referencing scheme that allows for simultaneous compensation of temperature drift and photobleaching. The technique relies on reference structures protected by locally dispensed passivation materials, and can be scaled to extended arrays of hundreds of devices. We prove the viability of the concept in a series of experiments, demonstrating robust and sensitive label-free detection over a wide range of constant or continuously varying temperatures. To the best of our knowledge, these measurements represent the first demonstration of biosensing in active WGM devices with simultaneous compensation of both photobleaching and temperature drift.

Bioassays with terrestrial and aquatic species as monitoring tools of hydrocarbon degradation.

PubMed

Bori, Jaume; Vallès, Bettina; Ortega, Lina; Riva, Maria Carme

2016-09-01

In this study chemical analyses and ecotoxicity tests were applied for the assessment of a heavily hydrocarbon-contaminated soil prior and after the application of a remediation procedure that consisted in the stimulation of soil autochthonous populations of hydrocarbon degraders in static-ventilated biopiles. Terrestrial bioassays were applied in mixtures of test soils and artificial control soil and studied the survival and reproduction of Eisenia fetida and the avoidance response of E. fetida and Folsomia candida. Effects on aquatic organisms were studied by means of acute tests with Vibrio fischeri, Raphidocelis subcapitata, and Daphnia magna performed on aqueous elutriates from test soils. The bioremediation procedure led to a significant reduction in the concentration of hydrocarbons (from 34264 to 3074 mg kg(-1), i.e., 91 % decrease) and toxicity although bioassays were not able to report a percentage decrease of toxicity as high as the percentage reduction. Sublethal tests proved the most sensitive terrestrial bioassays and avoidance tests with earthworms and springtails showed potential as monitoring tools of hydrocarbon remediation due to their high sensitivity and short duration. The concentrations of hydrocarbons in water extracts from test soils were 130 and 100 μg L(-1) before and after remediation, respectively. Similarly to terrestrial tests, most aquatic bioassays detected a significant reduction in toxicity, which was almost negligible at the end of the treatment. D. magna survival was the most affected by soil elutriates although toxicity to the crustacean was associated to the salinity of the samples rather than to the concentration of hydrocarbons. Ecotoxicity tests with aqueous soil elutriates proved less relevant in the assessment of hydrocarbon-contaminated soils due to the low hydrosolubility of hydrocarbons and the influence of the physicochemical parameters of the aquatic medium.

Role of Contrast-enhanced Ultrasound in the Evaluation of Inflammatory Arthritis

PubMed Central

Zhao, Chen-Yang; Jiang, Yu-Xin; Li, Jian-Chu; Xu, Zhong-Hui; Zhang, Qing; Su, Na; Yang, Meng

2017-01-01

Objective: Contrast-enhanced ultrasound (CEUS) is a well-established imaging modality which has been put into clinical use in recent years with the development of second-generation contrast agent and imaging devices, and its applications in the assessment of inflammatory arthritis, such as rheumatoid arthritis, psoriatic arthritis, and ankylosing spondylitis, have provoked abundant discussion and researches among radiologists and rheumatologists. To summarize the achievements of clinical studies on CEUS in the application of arthritis, and to keep up with the latest progresses of the imaging technique, we reviewed the literature in recent years, hoping to establish the role of CEUS in joint diseases. Data Sources: PubMed and EMBASE. Study Selection: We searched the database with the conditions “contrast-enhanced ultrasound AND arthritis” with the time limitation of recent 10 years. Clinical studies applying CEUS in inflammatory arthritis and review articles about development of CEUS in joint diseases in English were selected. Results: As it is proved by most studies in recent years, by delineating microvasculature within the inflamed joints, CEUS can indicate early arthritis with high sensitivity and specificity. Moreover, the imaging of CEUS has been proved to be consistent with histopathological changes of inflammatory arthritis. Quantitative analysis of CEUS permits further evaluation of disease activity. CEUS also plays a significant role in the therapeutic monitoring of the disease, which has been backed up by a number of studies. Conclusions: CEUS may be a new choice for the rheumatologists to evaluate inflammatory arthritis, because of its low price, ability to provide dynamic pictures, and high sensitivity to angiogenesis. It can also be applied in disease classification and therapeutic monitoring. More studies about CEUS need to be done to set up the diagnostic standards. PMID:28685724

Fluorescent probes for "off-on" highly sensitive detection of Hg²⁺ and L-cysteine based on nitrogen-doped carbon dots.

PubMed

Zhang, Yi; Cui, Peipei; Zhang, Feng; Feng, Xiaoting; Wang, Yaling; Yang, Yongzhen; Liu, Xuguang

2016-05-15

Fluorescent nitrogen-doped carbon dots (NCDs) were synthesized by a facile, and low-cost one-step hydrothermal strategy using citric acid as carbon source and ammonia solution as nitrogen source for the first time. The obtained NCDs show stable blue fluorescence with a high quantum yield of 35.4%, along with the fluorescence lifetime of ca. 6.75 ns. Most importantly, Hg(2+) can completely quench the fluorescence of NCDs as a result of the formation of a non-fluorescent stable NCDs-Hg(2+) complex. Static fluorescence quenching towards Hg(2+) is proved by the Stern-Volmer equation, ultraviolet-visible absorption spectra, temperature dependent quenching and fluorescence lifetime measurements. Subsequently, the fluorescence of the NCDs-Hg(2+) system is completely recovered with the addition L-cysteine (L-Cys) owing to the dissociation of NCDs-Hg(2+) complex to form a more stable Hg(2+)-L-Cys complex by Hg(2+)-S bonding. Therefore, such NCDs can be used as an effective fluorescent "turn-off" probe for rapid, rather highly selective and sensitive detection of Hg(2+), with a limit of detection (LOD) as low as 1.48 nM and a linear detection range of 0-10 μM. Interestingly, NCDs-Hg(2+) system can be conveniently employed as a fluorescent "turn-on" sensor for highly selective and sensitive detection of L-Cys with a low LOD of 0.79 nM and a wide linear detection range of 0-50 μM. Further, the sensitivity of NCDs to Hg(2+) is preserved in tap water with a LOD of 1.65 nM and a linear detection range of 0-10 μM. Copyright © 2016 Elsevier B.V. All rights reserved.

Shrub growth response to climate across the North Slope of Alaska

NASA Astrophysics Data System (ADS)

Ackerman, D.; Griffin, D.; Finlay, J. C.; Hobbie, S. E.

2016-12-01

Warmer temperatures at high latitudes are driving the expansion of woody shrubs in arctic tundra, yielding feedbacks to regional carbon cycling. Accounting for these feedbacks in global climate models will require accurate predictions of the spatial extent of shrub expansion within arctic tundra. While dendroecological approaches have proven useful in understanding how shrubs respond to climate, empirical studies to date are limited in spatial extent, often to just one or two sites within a landscape. A recent meta-analysis of such dendroecological studies hypothesizes that soil moisture is a key variable in determining climate sensitivity of arctic shrub growth. We present the first regional-scale empirical test of this hypothesis by analyzing inter-annual radial growth of deciduous shrubs across soil moisture gradients throughout the North Slope of Alaska. Contrary to expectation, riparian shrubs in high-moisture environments showed no climate sensitivity, while shrubs growing in drier upland sites showed a strong positive growth response to summer temperature. These results proved robust to a variety of detrending functions ranging from conservative (negative exponential) to data adaptive (20-year cubic smoothing spline). These findings call into question the role of soil moisture in determining the climate sensitivity of arctic shrubs and further highlight the importance of unified, regional-scale sampling strategies in understanding climate-vegetation links.

Superior piezoelectric composite films: taking advantage of carbon nanomaterials.

PubMed

Saber, Nasser; Araby, Sherif; Meng, Qingshi; Hsu, Hung-Yao; Yan, Cheng; Azari, Sara; Lee, Sang-Heon; Xu, Yanan; Ma, Jun; Yu, Sirong

2014-01-31

Piezoelectric composites comprising an active phase of ferroelectric ceramic and a polymer matrix have recently found numerous sensory applications. However, it remains a major challenge to further improve their electromechanical response for advanced applications such as precision control and monitoring systems. We here investigated the incorporation of graphene platelets (GnPs) and multi-walled carbon nanotubes (MWNTs), each with various weight fractions, into PZT (lead zirconate titanate)/epoxy composites to produce three-phase nanocomposites. The nanocomposite films show markedly improved piezoelectric coefficients and electromechanical responses (50%) besides an enhancement of ~200% in stiffness. The carbon nanomaterials strengthened the impact of electric field on the PZT particles by appropriately raising the electrical conductivity of the epoxy. GnPs have been proved to be far more promising in improving the poling behavior and dynamic response than MWNTs. The superior dynamic sensitivity of GnP-reinforced composite may be caused by the GnPs' high load transfer efficiency arising from their two-dimensional geometry and good compatibility with the matrix. The reduced acoustic impedance mismatch resulting from the improved thermal conductance may also contribute to the higher sensitivity of GnP-reinforced composite. This research pointed out the potential of employing GnPs to develop highly sensitive piezoelectric composites for sensing applications.

Enhancement of Energy Conversion Efficiency for Dye Sensitized Solar Cell Using Zinc Oxide Photoanode

NASA Astrophysics Data System (ADS)

Jamalullail, N.; Smohamad, I.; Nnorizan, M.; Mahmed, N.

2018-06-01

Dye sensitized solar cell (DSSC) is a third generation solar cell that is well known for its low cost, simple fabrication process and promised reasonable energy conversion efficiency. Basic structure of DSSC is composed of photoanode, dye sensitizer, electrolyte that is sandwiched together in between two transparent conductive oxide (TCO) glasses. Each of the components in the DSSC contributes important role that affect the energy conversion efficiency. In this research, the commonly used titanium dioxide (TiO2) photoanode has previously reported to have high recombination rate and low electron mobility which caused efficiency loss had been compared with the zinc oxide (ZnO) photoanode with high electron mobility (155 cm2V-1s-1). Both of these photoanodes had been deposited through doctor blade technique. The electrical performance of the laboratory based DSSCs were tested using solar cell simulator and demonstrated that ZnO is a better photoanode compared to TiO2 with the energy conversion efficiency of 0.34% and 0.29% respectively. Nanorods shape morphology was observed in ZnO photoanode with average particle size of 41.60 nm and average crystallite size of 19.13 nm. This research proved that the energy conversion efficiency of conventional TiO2 based photoanode can be improved using ZnO material.

Ovine echinococcosis I. Immunological diagnosis by enzyme immunoassay.

PubMed

Gatti, Antonio; Alvarez, Angela Rosa; Araya, Daniel; Mancini, Sergio; Herrero, Eduardo; Santillan, Graciela; Larrieu, Edmundo

2007-01-31

Immunodiagnosis in sheep presents problems of sensitivity and specificity, limiting its applicability in surveillance systems. The objective of this study was to develop a sensitive, specific and accessible technique for diagnosing cystic echinococcosis in naturally infected sheep and to evaluate the validity of necropsy as a reference test. A total of 247 sheep were studied at slaughterhouses, confirming the parasitological diagnosis with histology. Serum was processed with enzyme immunoassay (EIA) using three antigen preparations: total hydatid liquid (LHT), purified fraction of LHT (S2B) and purified lipoprotein (B). Western Blot (WB) was used as a control. EIA proved effective for differentiating Echinococcus granulosus from larval stage of Taenia hydatigena and intestinal cestodes in all three antigen preparations. Serums from macroscopically negative sheep were reactive to EIA and positive with WB. In the whole flock, sensitivity was 89.2% for LHT, 80.0% for S2B and 86.4% for B. Sensitivity in lambs was 78.6% for LHT, 75.0% for S2B and 64.3% for B. Macroscopic diagnosis at the time of slaughter was found to have limitations as a reference test for immunodiagnosis of cystic equinococcosis in sheep, so it was necessary to include histology and WB as reference tests. LHT was the antigen preparation of greatest value and EIA proved to be a sensitive and specific technique, adequate for surveillance systems and for evaluating control programmes.

A wireless beta-microprobe based on pixelated silicon for in vivo brain studies in freely moving rats

NASA Astrophysics Data System (ADS)

Märk, J.; Benoit, D.; Balasse, L.; Benoit, M.; Clémens, J. C.; Fieux, S.; Fougeron, D.; Graber-Bolis, J.; Janvier, B.; Jevaud, M.; Genoux, A.; Gisquet-Verrier, P.; Menouni, M.; Pain, F.; Pinot, L.; Tourvielle, C.; Zimmer, L.; Morel, C.; Laniece, P.

2013-07-01

The investigation of neurophysiological mechanisms underlying the functional specificity of brain regions requires the development of technologies that are well adjusted to in vivo studies in small animals. An exciting challenge remains the combination of brain imaging and behavioural studies, which associates molecular processes of neuronal communications to their related actions. A pixelated intracerebral probe (PIXSIC) presents a novel strategy using a submillimetric probe for beta+ radiotracer detection based on a pixelated silicon diode that can be stereotaxically implanted in the brain region of interest. This fully autonomous detection system permits time-resolved high sensitivity measurements of radiotracers with additional imaging features in freely moving rats. An application-specific integrated circuit (ASIC) allows for parallel signal processing of each pixel and enables the wireless operation. All components of the detector were tested and characterized. The beta+ sensitivity of the system was determined with the probe dipped into radiotracer solutions. Monte Carlo simulations served to validate the experimental values and assess the contribution of gamma noise. Preliminary implantation tests on anaesthetized rats proved PIXSIC's functionality in brain tissue. High spatial resolution allows for the visualization of radiotracer concentration in different brain regions with high temporal resolution.

Novel Gyroscopic Mounting for Crystal Oscillators to Increase Short and Medium Term Stability under Highly Dynamic Conditions.

PubMed

Abedi, Maryam; Jin, Tian; Sun, Kewen

2015-06-17

In this paper, a gyroscopic mounting method for crystal oscillators to reduce the impact of dynamic loads on their output stability has been proposed. In order to prove the efficiency of this mounting approach, each dynamic load-induced instability has been analyzed in detail. A statistical study has been performed on the elevation angle of the g-sensitivity vector of Stress Compensated-cut (SC-cut) crystals. The analysis results show that the proposed gyroscopic mounting method gives good performance for host vehicle attitude changes. A phase noise improvement of 27 dB maximum and 5.7 dB on average can be achieved in the case of steady state loads, while under sinusoidal vibration conditions, the maximum and average phase noise improvement are as high as 24 dB and 7.5 dB respectively. With this gyroscopic mounting method, random vibration-induced phase noise instability is reduced 30 dB maximum and 8.7 dB on average. Good effects are apparent for crystal g-sensitivity vectors with low elevation angle φ and azimuthal angle β. under highly dynamic conditions, indicating the probability that crystal oscillator instability will be significantly reduced by using the proposed mounting approach.

Latest advances in confocal microscopy of skin cancers toward guiding patient care: a Mohs surgeon's review and perspective (Conference Presentation)

NASA Astrophysics Data System (ADS)

Nehal, Kishwer S.; Rajadhyaksha, Milind

2016-02-01

Latest advances in confocal microscopy of skin cancers toward guiding patient care: a Mohs surgeon's review and perspective About 350 publications worldwide have reported the ability of reflectance confocal microscopy (RCM) imaging to detect melanocytic skin lesions in vivo with specificity of 84-88% and sensitivity of 71-92%, and non-melanocytic skin lesions with specificity of 85-97% and sensitivity 100-92%. Lentigo maligna melanoma can be detected with sensitivity of 93% and specificity 82%. While the sensitivity is comparable to that of dermoscopy, the specificity is 2X superior, especially for lightly- and non-pigmented lesions. Dermoscopy combined with RCM imaging is proving to be both highly sensitive and highly specific. Recent studies have reported that the ratio of equivocal (i.e., would have been biopsied) lesions to detected melanomas dropped by ~2X when guided by dermoscopy and RCM imaging, compared to that with dermoscopy alone. Dermoscopy combined with RCM imaging is now being implemented to guide noninvasive diagnosis (to rule out malignancy and biopsy) and to also guide treatment, with promising initial impact: thus far, about 3,000 patients have been saved from biopsies of benign lesions. These are currently under follow-up monitoring. With fluorescence confocal microscopy (FCM) mosaicing, residual basal cell carcinomas can be detected in Mohs surgically excised fresh tissue ex vivo, with sensitivity of 94-97% and specificity 89-94%. FCM mosaicing is now being implemented for guiding Mohs surgery. To date, about 600 Mohs procedures have been performed, guided with mosaicing, and with pathology being performed in parallel to confirm the final outcome. These latest advances demonstrate the promising ability of RCM and FCM to guide patient care.

A Small Range Six-Axis Accelerometer Designed with High Sensitivity DCB Elastic Element

PubMed Central

Sun, Zhibo; Liu, Jinhao; Yu, Chunzhan; Zheng, Yili

2016-01-01

This paper describes a small range six-axis accelerometer (the measurement range of the sensor is ±g) with high sensitivity DCB (Double Cantilever Beam) elastic element. This sensor is developed based on a parallel mechanism because of the reliability. The accuracy of sensors is affected by its sensitivity characteristics. To improve the sensitivity, a DCB structure is applied as the elastic element. Through dynamic analysis, the dynamic model of the accelerometer is established using the Lagrange equation, and the mass matrix and stiffness matrix are obtained by a partial derivative calculation and a conservative congruence transformation, respectively. By simplifying the structure of the accelerometer, a model of the free vibration is achieved, and the parameters of the sensor are designed based on the model. Through stiffness analysis of the DCB structure, the deflection curve of the beam is calculated. Compared with the result obtained using a finite element analysis simulation in ANSYS Workbench, the coincidence rate of the maximum deflection is 89.0% along the x-axis, 88.3% along the y-axis and 87.5% along the z-axis. Through strain analysis of the DCB elastic element, the sensitivity of the beam is obtained. According to the experimental result, the accuracy of the theoretical analysis is found to be 90.4% along the x-axis, 74.9% along the y-axis and 78.9% along the z-axis. The measurement errors of linear accelerations ax, ay and az in the experiments are 2.6%, 0.6% and 1.31%, respectively. The experiments prove that accelerometer with DCB elastic element performs great sensitive and precision characteristics. PMID:27657089

Structural stability and chaotic solutions of perturbed Benjamin-Ono equations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Birnir, B.; Morrison, P.J.

1986-11-01

A method for proving chaos in partial differential equations is discussed and applied to the Benjamin-Ono equation subject to perturbations. The perturbations are of two types: one that corresponds to viscous dissipation, the so-called Burger's term, and one that involves the Hilbert transform and has been used to model Landau damping. The method proves chaos in the PDE by proving temporal chaos in its pole solutions. The spatial structure of the pole solutions remains intact, but their positions are chaotic in time. Melnikov's method is invoked to show this temporal chaos. It is discovered that the pole behavior is verymore » sensitive to the Burger's perturbation, but is quite insensitive to the perturbation involving the Hilbert transform.« less

Infrasonic and Ultrasonic Hearing Evolved after the Emergence of Modern Whales.

PubMed

Mourlam, Mickaël J; Orliac, Maeva J

2017-06-19

Mysticeti (baleen whales) and Odontoceti (toothed whales) today greatly differ in their hearing abilities: Mysticeti are presumed to be sensitive to infrasonic noises [1-3], whereas Odontoceti are sensitive to ultrasonic sounds [4-6]. Two competing hypotheses exist regarding the attainment of hearing abilities in modern whales: ancestral low-frequency sensitivity [7-13] or ancestral high-frequency sensitivity [14, 15]. The significance of these evolutionary scenarios is limited by the undersampling of both early-diverging cetaceans (archaeocetes) and terrestrial hoofed relatives of cetaceans (non-cetacean artiodactyls). Here, we document for the first time the bony labyrinth, the hollow cavity housing the hearing organ, of two species of protocetid whales from Lutetian deposits (ca. 46-43 Ma) of Kpogamé, Togo. These archaeocete cetaceans, which are transitional between terrestrial and aquatic forms, prove to be a key for determining the hearing abilities of early whales. We propose a new evolutionary picture for the early stages of this history, based on qualitative and quantitative studies of the cochlear morphology of an unparalleled sample of extant and extinct land artiodactyls and cetaceans. Contrary to the hypothesis that archaeocetes have been more sensitive to high-frequency sounds than their terrestrial ancestors [15], we demonstrate that early cetaceans presented a cochlear functional pattern close to that of their terrestrial relatives, and that specialization for infrasonic or ultrasonic hearing in Mysticeti or Odontoceti, respectively, instead only occurred in fully aquatic whales, after the emergence of Neoceti (Mysticeti+Odontoceti). Copyright © 2017 Elsevier Ltd. All rights reserved.

Automated Processing of Dynamic Contrast-Enhanced MRI: Correlation of Advanced Pharmacokinetic Metrics with Tumor Grade in Pediatric Brain Tumors.

PubMed

Vajapeyam, S; Stamoulis, C; Ricci, K; Kieran, M; Poussaint, T Young

2017-01-01

Pharmacokinetic parameters from dynamic contrast-enhanced MR imaging have proved useful for differentiating brain tumor grades in adults. In this study, we retrospectively reviewed dynamic contrast-enhanced perfusion data from children with newly diagnosed brain tumors and analyzed the pharmacokinetic parameters correlating with tumor grade. Dynamic contrast-enhanced MR imaging data from 38 patients were analyzed by using commercially available software. Subjects were categorized into 2 groups based on pathologic analyses consisting of low-grade (World Health Organization I and II) and high-grade (World Health Organization III and IV) tumors. Pharmacokinetic parameters were compared between the 2 groups by using linear regression models. For parameters that were statistically distinct between the 2 groups, sensitivity and specificity were also estimated. Eighteen tumors were classified as low-grade, and 20, as high-grade. Transfer constant from the blood plasma into the extracellular extravascular space (K trans ), rate constant from extracellular extravascular space back into blood plasma (K ep ), and extracellular extravascular volume fraction (V e ) were all significantly correlated with tumor grade; high-grade tumors showed higher K trans , higher K ep , and lower V e . Although all 3 parameters had high specificity (range, 82%-100%), K ep had the highest specificity for both grades. Optimal sensitivity was achieved for V e , with a combined sensitivity of 76% (compared with 71% for K trans and K ep ). Pharmacokinetic parameters derived from dynamic contrast-enhanced MR imaging can effectively discriminate low- and high-grade pediatric brain tumors. © 2017 by American Journal of Neuroradiology.

Enzyme responsive drug delivery system based on mesoporous silica nanoparticles for tumor therapy in vivo

NASA Astrophysics Data System (ADS)

Liu, Yun; Ding, Xingwei; Li, Jinghua; Luo, Zhong; Hu, Yan; Liu, Junjie; Dai, Liangliang; Zhou, Jun; Hou, Changjun; Cai, Kaiyong

2015-04-01

To reduce the toxic side effects of traditional chemotherapeutics in vivo, we designed and constructed a biocompatible, matrix metalloproteinases (MMPs) responsive drug delivery system based on mesoporous silica nanoparticles (MSNs). MMPs substrate peptide containing PLGLAR (sensitive to MMPs) was immobilized onto the surfaces of amino-functionalized MSNs via an amidation reaction, serving as MMPs sensitive intermediate linker. Bovine serum albumin was then covalently coupled to linker as end-cap for sealing the mesopores of MSNs. Lactobionic acid was further conjugated to the system as targeting motif. Doxorubicin hydrochloride was used as the model anticancer drug in this study. A series of characterizations revealed that the system was successfully constructed. The peptide-functionalized MSNs system demonstrated relatively high sensitivity to MMPs for triggering drug delivery, which was potentially important for tumor therapy since the tumor’s microenvironment overexpressed MMPs in nature. The in vivo experiments proved that the system could efficiently inhibit the tumor growth with minimal side effects. This study provides an approach for the development of the next generation of nanotherapeutics toward efficient cancer treatment.

[What is hidden behind the Baking Tray Task? Study of sensibility and specificity in right-hemispheric stroke patients].

PubMed

Garcia-Fernandez, Juan; Garcia-Molina, Alberto; Aparicio-Lopez, Celeste; Sanchez-Carrion, Rocío; Ensenat, Antònia; Pena-Casanova, Jordi; Roig-Rovira, Teresa

2015-12-16

Tham and Tegner proposed the Baking Tray Task (BTT) as a fast simple assessment test for detecting spatial negligence. However, very few studies have examined its validity as a diagnostic test. To analyse the diagnostic validity of the BTT by measuring its specificity and sensitivity in a sample of subjects with right hemisphere strokes. Forty-eight patients with right hemisphere vascular lesions were distributed in two groups (negligence group, n = 35; non-negligence group, n = 13) according to the scores obtained in a battery of visuospatial examination tests. The participants' performance on the BTT was compared with that of a healthy control group (n = 12). The results showed a high level of sensitivity of the BTT, but low specificity. The performance on the BTT of eight of the 13 members of the non-negligence group was suggestive of negligence. The BTT has proved to be a sensitive test for the detection of spatial negligence. Yet, based on its low specificity, its use alone as a single diagnostic test is not recommended.

Age estimation using cortical surface pattern combining thickness with curvatures

PubMed Central

Wang, Jieqiong; Li, Wenjing; Miao, Wen; Dai, Dai; Hua, Jing; He, Huiguang

2014-01-01

Brain development and healthy aging have been proved to follow a specific pattern, which, in turn, can be applied to help doctors diagnose mental diseases. In this paper, we design a cortical surface pattern (CSP) combining the cortical thickness with curvatures, which constructs an accurate human age estimation model with relevance vector regression. We test our model with two public databases. One is the IXI database (360 healthy subjects aging from 20 to 82 years old were selected), and the other is the INDI database (303 subjects aging from 7 to 22 years old were selected). The results show that our model can achieve as small as 4.57 years deviation in the IXI database and 1.38 years deviation in the INDI database. Furthermore, we employ this surface pattern to age groups classification, and get a remarkably high accuracy (97.77%) and a significantly high sensitivity/specificity (97.30%/98.10%). These results suggest that our designed CSP combining thickness with curvatures is stable and sensitive to brain development, and it is much more powerful than voxel-based morphometry used in previous methods for age estimation. PMID:24395657

Study of different 3-aminopropyl triethoxysilane (APTES) concentration on TiO2 particles based IDE for cervical cancer detection

NASA Astrophysics Data System (ADS)

Raqeema, S.; Hashim, U.; Azizah, N.; Nadzirah, Sh.; Arshad, M. K. Md; Ruslinda, A. R.; Gopinath, Subash C. B.

2017-03-01

HPV that also called Human Papillomaviruses is the major cause of the cervical cancer. HPV 16 and HPV 18 are the two types of HPV are the most HPV-associated cancers and responsible as a high-risk HPV. Cervical cancer taken about 70 percent of all cases due HPV infections. Cervical malignancy for the most part development on a lady's cervix and its was developed slowly as cancer disease. TiO2 particles give better performance and low cost of the biosensor. The used of 3-aminopropyl triethoxysilane (APTES) will be more efficient for DNA nanochip. APTES used as absorption reaction to immobilize organic biomolecules on the inorganic surface. Besides, APTES give better functionalization of the adsorption mechanism on IDE. The surface functionalized for immobilizing the DNA, which is the combination of the DNA probe and the HPV target produce high sensitivity andfast detection of the IDE. The Current-Voltage (IV) characteristic proved the sensitivity of the DNA nanochip increase as the concentration varied from 0% concentration to 24% of APTES concentration.

Biogenic unmodified gold nanoparticles for selective and quantitative detection of cerium using UV-vis spectroscopy and photon correlation spectroscopy (DLS).

PubMed

Priyadarshini, E; Pradhan, N; Panda, P K; Mishra, B K

2015-06-15

The ability of self-functionalized biogenic GNPs towards highly selective colorimetric detection of rare earth element cerium is being reported for the first time. GNPs underwent rapid aggregation on addition of cerium indicated by red shift of SPR peak followed by complete precipitation. Hereby, this concept of co-ordination of cerium ions onto the GNP surface has been utilized for detection of cerium. The remarkable capacity of GNPs to sensitively detect Ce without proves beneficial compared to previous reports of colorimetric sensing. MDL was 15 and 35 ppm by DLS and UV-vis spectroscopy respectively, suggesting DLS to be highly sensitive and a practical alternative in ultrasensitive detection studies. The sensing system showed a good linear fit favouring feasible detection of cerium in range of 2-50 ppm. Similar studies further showed the superior selectivity of biogenic GNPs compared to chemically synthesized counterparts. The sensing system favours on-site analysis as it overcomes need of complex instrumentation, lengthy protocols and surface modification of GNP. Copyright © 2015 Elsevier B.V. All rights reserved.

Effective PCR detection of animal species in highly processed animal byproducts and compound feeds.

PubMed

Fumière, Olivier; Dubois, Marc; Baeten, Vincent; von Holst, Christoph; Berben, Gilbert

2006-07-01

In this paper we present a polymerase chain reaction (PCR)-based method for detecting meat and bone meal (MBM) in compound feedingstuffs. By choosing adequate DNA targets from an appropriate localisation in the genome, the real-time PCR method developed here proved to be robust to severe heat treatment of the MBM, showing high sensitivity in the detection of MBM. The method developed here permits the specific detection of processed pig and cattle materials treated at 134 degrees C in various feed matrices down to a limit of detection of about 0.1%. This technique has also been successfully applied to well-characterised MBM samples heated to as high as 141 degrees C, as well as to various blind feed samples with very low MBM contents. Finally, the method also passed several official European ring trials.

Interference Confocal Microscope Integrated with Spatial Phase Shifter.

PubMed

Wang, Weibo; Gu, Kang; You, Xiaoyu; Tan, Jiubin; Liu, Jian

2016-08-24

We present an interference confocal microscope (ICM) with a new single-body four-step simultaneous phase-shifter device designed to obtain high immunity to vibration. The proposed ICM combines the respective advantages of simultaneous phase shifting interferometry and bipolar differential confocal microscopy to obtain high axis resolution, large dynamic range, and reduce the sensitivity to vibration and reflectance disturbance seamlessly. A compact single body spatial phase shifter is added to capture four phase-shifted interference signals simultaneously without time delay and construct a stable and space-saving simplified interference confocal microscope system. The test result can be obtained by combining the interference phase response and the bipolar property of differential confocal microscopy without phase unwrapping. Experiments prove that the proposed microscope is capable of providing stable measurements with 1 nm of axial depth resolution for either low- or high-numerical aperture objective lenses.

Cost-effectiveness analysis of different types of human papillomavirus vaccination combined with a cervical cancer screening program in mainland China.

PubMed

Mo, Xiuting; Gai Tobe, Ruoyan; Wang, Lijie; Liu, Xianchen; Wu, Bin; Luo, Huiwen; Nagata, Chie; Mori, Rintaro; Nakayama, Takeo

2017-07-18

China has a high prevalence of human papillomavirus (HPV) and a consequently high burden of disease with respect to cervical cancer. The HPV vaccine has proved to be effective in preventing cervical cancer and is now a part of routine immunization programs worldwide. It has also proved to be cost effective. This study aimed to assess the cost-effectiveness of 2-, 4-, and 9-valent HPV vaccines (hereafter, HPV2, 4 or 9) combined with current screening strategies in China. A Markov model was developed for a cohort of 100,000 HPV-free girls to simulate the natural history to HPV infection. Three recommended screening methods (1. liquid-based cytology test + HPV DNA test; 2. pap smear cytology test + HPV DNA test; 3. visual inspection with acetic acid) and three types of HPV vaccination program (HPV2/4/9) were incorporated into 15 intervention options, and the incremental cost-effectiveness ratio (ICER) was calculated to determine the dominant strategies. Costs, transition probabilities and utilities were obtained from a review of the literature and national databases. One-way sensitivity analyses and threshold analyses were performed for key variables in different vaccination scenarios. HPV9 combined with screening showed the highest health impact in terms of reducing HPV-related diseases and increasing the number of quality-adjusted life years (QALYs). Under the current thresholds of willingness to pay (WTP, 3 times the per capita GDP or USD$ 23,880), HPV4/9 proved highly cost effective, while HPV2 combined with screening cost more and was less cost effective. Only when screening coverage increased to 60% ~ 70% did the HPV2 and screening combination strategy become economically feasible. The combination of the HPV4/9 vaccine with current screening strategies for adolescent girls was highly cost-effective and had a significant impact on reducing the HPV infection-related disease burden in Mainland China.

A high-sensitivity ultra-high performance liquid chromatography/high-resolution time-of-flight mass spectrometry (UHPLC-HR-TOFMS) method for screening synthetic cannabinoids and other drugs of abuse in urine.

PubMed

Sundström, Mira; Pelander, Anna; Angerer, Verena; Hutter, Melanie; Kneisel, Stefan; Ojanperä, Ilkka

2013-10-01

The continuing emergence of designer drugs imposes high demands on the scope and sensitivity of toxicological drug screening procedures. An ultra-high performance liquid chromatography/high-resolution time-of-flight mass spectrometry (UHPLC-HR-TOFMS) method was developed for screening and simultaneous confirmation of both designer drugs and other drugs of abuse in urine samples in a single run. The method covered selected synthetic cannabinoids and cathinones, amphetamines, natural cannabinoids, opioids, cocaine and other important drugs of abuse, together with their main urinary metabolites. The database consisted of 277 compounds with molecular formula and exact monoisotopic mass; retention time was included for 192 compounds, and primary and secondary qualifier ion exact mass for 191 and 95 compounds, respectively. Following a solid-phase extraction, separation was performed by UHPLC and mass analysis by HR-TOFMS. MS, and broad-band collision-induced dissociation data were acquired at m/z range 50-700. Compound identification was based on a reverse database search with acceptance criteria for retention time, precursor ion mass accuracy, isotopic pattern and abundance of qualifier ions. Mass resolving power in spiked urine samples was on average FWHM 23,500 and mass accuracy 0.3 mDa. The mean and median cut-off concentrations determined for 75 compounds were 4.2 and 1 ng/mL, respectively. The range of cut-off concentrations for synthetic cannabinoids was 0.2-60 ng/mL and for cathinones 0.7-15 ng/mL. The method proved to combine high sensitivity and a wide scope in a manner not previously reported in drugs of abuse screening. The method's feasibility was demonstrated with 50 authentic urine samples.

Nano Superconducting Quantum Interference device: A powerful tool for nanoscale investigations

NASA Astrophysics Data System (ADS)

Granata, Carmine; Vettoliere, Antonio

2016-02-01

The magnetic sensing at nanoscale level is a promising and interesting research topic of nanoscience. Indeed, magnetic imaging is a powerful tool for probing biological, chemical and physical systems. The study of small spin cluster, like magnetic molecules and nanoparticles, single electron, cold atom clouds, is one of the most stimulating challenges of applied and basic research of the next years. In particular, the magnetic nanoparticle investigation plays a fundamental role for the modern material science and its relative technological applications like ferrofluids, magnetic refrigeration and biomedical applications, including drug delivery, hyper-thermia cancer treatment and magnetic resonance imaging contrast-agent. Actually, one of the most ambitious goals of the high sensitivity magnetometry is the detection of elementary magnetic moment or spin. In this framework, several efforts have been devoted to the development of a high sensitivity magnetic nanosensor pushing sensing capability to the individual spin level. Among the different magnetic sensors, Superconducting QUantum Interference Devices (SQUIDs) exhibit an ultra high sensitivity and are widely employed in numerous applications. Basically, a SQUID consists of a superconducting ring (sensitive area) interrupted by two Josephson junctions. In the recent years, it has been proved that the magnetic response of nano-objects can be effectively measured by using a SQUID with a very small sensitive area (nanoSQUID). In fact, the sensor noise, expressed in terms of the elementary magnetic moment (spin or Bohr magneton), is linearly dependent on the SQUID loop side length. For this reason, SQUIDs have been progressively miniaturized in order to improve the sensitivity up to few spin per unit of bandwidth. With respect to other techniques, nanoSQUIDs offer the advantage of direct measurement of magnetization changes in small spin systems. In this review, we focus on nanoSQUIDs and its applications. In particular, we will discuss the motivations, the theoretical aspects, the fabrication techniques, the different nanoSQUIDs and the relative nanoscale applications.

Systemic analysis of different colorectal cancer cell lines and TCGA datasets identified IGF-1R/EGFR-PPAR-CASPASE axis as important indicator for radiotherapy sensitivity.

PubMed

Chen, Lin; Zhu, Zhe; Gao, Wei; Jiang, Qixin; Yu, Jiangming; Fu, Chuangang

2017-09-05

Insulin-like growth factor 1 receptor (IGF-1R) is proved to contribute the development of many types of cancers. But, little is known about its roles in radio-resistance of colorectal cancer (CRC). Here, we demonstrated that low IGF-1R expression value was associated with the better radiotherapy sensitivity of CRC. Besides, through Quantitative Real-time PCR (qRT-PCR), the elevated expression value of epidermal growth factor receptor (EGFR) was observed in CRC cell lines (HT29, RKO) with high radio-sensitivity compared with those with low sensitivity (SW480, LOVO). The irradiation induced apoptosis rates of wild type and EGFR agonist (EGF) or IGF-1R inhibitor (NVP-ADW742) treated HT29 and SW480 cells were quantified by flow cytometry. As a result, the apoptosis rate of EGF and NVP-ADW742 treated HT29 cells was significantly higher than that of those wild type ones, which indicated that high EGFR and low IGF-1R expression level in CRC was associated with the high sensitivity to radiotherapy. We next conducted systemic bioinformatics analysis of genome-wide expression profiles of CRC samples from the Cancer Genome Atlas (TCGA). Differential expression analysis between IGF-1R and EGFR abnormal CRC samples, i.e. CRC samples with higher IGF-1R and lower EGFR expression levels based on their median expression values, and the rest of CRC samples identified potential genes contribute to radiotherapy sensitivity. Functional enrichment of analysis of those differential expression genes (DEGs) in the Database for Annotation, Visualization and Integrated Discovery (DAVID) indicated PPAR signaling pathway as an important pathway for the radio-resistance of CRC. Our study identified the potential biomarkers for the rational selection of radiotherapy for CRC patients. Copyright © 2017 Elsevier B.V. All rights reserved.

Novel LC/MS/MS and High-Throughput Mass Spectrometric Assays for Monoacylglycerol Acyltransferase Inhibitors.

PubMed

Qi, Jenson; Masucci, John A; Lang, Wensheng; Connelly, Margery A; Caldwell, Gary W; Petrounia, Ioanna; Kirkpatrick, Jennifer; Barnakov, Alexander N; Struble, Geoffrey; Miller, Robyn; Dzordzorine, Keli; Kuo, Gee-Hong; Gaul, Michael; Pocai, Alessandro; Lee, Seunghun

2017-04-01

Monoacylglycerol acyltransferase enzymes (MGAT1, MGAT2, and MGAT3) convert monoacylglycerol to diacylglycerol (DAG). MGAT1 and MGAT2 are both implicated in obesity-related metabolic diseases. Conventional MGAT enzyme assays use radioactive substrates, wherein the product of the MGAT-catalyzed reaction is usually resolved by time-consuming thin layer chromatography (TLC) analysis. Furthermore, microsomal membrane preparations typically contain endogenous diacylglycerol acyltransferase (DGAT) from the host cells, and these DGAT activities can further acylate DAG to form triglyceride (TG). Our mass spectrometry (liquid chromatography-tandem mass spectrometry, or LC/MS/MS) MGAT2 assay measures human recombinant MGAT2-catalyzed formation of didecanoyl-glycerol from 1-decanoyl-rac-glycerol and decanoyl-CoA, to produce predominantly 1,3-didecanoyl-glycerol. Unlike 1,2-DAG, 1,3-didecanoyl-glycerol is proved to be not susceptible to further acylation to TG. 1,3-Didecanoyl-glycerol product can be readily solubilized and directly subjected to high-throughput mass spectrometry (HTMS) without further extraction in a 384-well format. We also have established the LC/MS/MS MGAT activity assay in the intestinal microsomes from various species. Our assay is proved to be highly sensitive, and thus it allows measurement of endogenous MGAT activity in cell lysates and tissue preparations. The implementation of the HTMS MGAT activity assay has facilitated the robust screening and evaluation of MGAT inhibitors for the treatment of metabolic diseases.

Frequency dependence of sensitivities in second-order RC active filters

NASA Astrophysics Data System (ADS)

Kunieda, T.; Hiramatsu, Y.; Fukui, A.

1980-02-01

This paper presents that gain and phase sensitivities to some element in biquadratic filters approximately constitute a circle on the complex sensitivity plane, provided that the quality factor Q of the circuit is appreciably larger than unity. Moreover, the group delay sensitivity is represented by the imaginary part of a cardioid. Using these results, bounds of maximum values of gain, phase, and group delay sensitivities are obtained. Further, it is proved that the maximum values of these sensitivities can be simultaneously minimized by minimizing the absolute value of the transfer function sensitivity at the center frequency provided that w(0)-sensitivities are constant and do not contain design parameters. Next, a statistical variability measure for the optimal-filter design is proposed. Finally, the relation between some variability measures proposed to the present time is made clear.

Comparative sequence analysis of acid sensitive/resistance proteins in Escherichia coli and Shigella flexneri

PubMed Central

Manikandan, Selvaraj; Balaji, Seetharaaman; Kumar, Anil; Kumar, Rita

2007-01-01

The molecular basis for the survival of bacteria under extreme conditions in which growth is inhibited is a question of great current interest. A preliminary study was carried out to determine residue pattern conservation among the antiporters of enteric bacteria, responsible for extreme acid sensitivity especially in Escherichia coli and Shigella flexneri. Here we found the molecular evidence that proved the relationship between E. coli and S. flexneri. Multiple sequence alignment of the gadC coded acid sensitive antiporter showed many conserved residue patterns at regular intervals at the N-terminal region. It was observed that as the alignment approaches towards the C-terminal, the number of conserved residues decreases, indicating that the N-terminal region of this protein has much active role when compared to the carboxyl terminal. The motif, FHLVFFLLLGG, is well conserved within the entire gadC coded protein at the amino terminal. The motif is also partially conserved among other antiporters (which are not coded by gadC) but involved in acid sensitive/resistance mechanism. Phylogenetic cluster analysis proves the relationship of Escherichia coli and Shigella flexneri. The gadC coded proteins are converged as a clade and diverged from other antiporters belongs to the amino acid-polyamine-organocation (APC) superfamily. PMID:21670792

Graphene based strain sensor with LCP substrate

NASA Astrophysics Data System (ADS)

Nie, M.; Yang, H. S.; Xia, Y. H.

2018-02-01

A flexible strain sensor constructed by an efficient, low-cost fabrication strategy is presented in this paper. It is assembled by adhering grid-like graphene on LCP substrate. Kinds of measurement setup have been designed to verify that the proposed flexible sensor device is suitable to be used in health monitoring system. From the experiment results, it can be proved that the sensor exhibits the following features: ultra-light, relatively good sensitivity, high reversibility, superior physical robustness, easy fabrication. With the great performance of this flexible strain sensor, it is considered to play an important role in body monitoring, structural health monitoring system, fatigue detection and healthcare systems in the near future.

[A digital micromirror device-based Hadamard transform near infrared spectrometer].

PubMed

Liu, Jia; Chen, Fen-Fei; Liao, Cheng-Sheng; Xu, Qian; Zeng, Li-Bo; Wu, Qiong-Shui

2011-10-01

A Hadamard transform near infrared spectrometer based on a digital micromirror device was constructed. The optical signal was collected by optical fiber, a grating was used for light diffraction, a digital micromirror device (DMD) was applied instead of traditional mechanical Hadamard masks for optical modulation, and an InGaAs near infrared detector was used as the optic sensor. The original spectrum was recovered by fast Hadamard transform algrithms. The advantages of the spectrometer, such as high resolution, signal-noise-ratio, stability, sensitivity and response speed were proved by experiments, which indicated that it is very suitable for oil and food-safety applications.

An extraordinary directive radiation based on optical antimatter at near infrared.

PubMed

Mocella, Vito; Dardano, Principia; Rendina, Ivo; Cabrini, Stefano

2010-11-22

In this paper we discuss and experimentally demonstrate that in a quasi- zero-average-refractive-index (QZAI) metamaterial, in correspondence of a divergent source in near infrared (λ = 1.55 μm) the light scattered out is extremely directive (Δθ(out) = 0.06°), coupling with diffraction order of the alternating complementary media grating. With a high degree of accuracy the measurements prove also the excellent vertical confinement of the beam even in the air region of the metamaterial, in absence of any simple vertical confinement mechanism. This extremely sensitive device works on a large contact area and open news perspective to integrated spectroscopy.

Expeditious microwave-assisted synthesis of 5-alkoxyoxazoles from α-triflyloxy esters and nitriles.

PubMed

Jouanno, Laurie-Anne; Sabot, Cyrille; Renard, Pierre-Yves

2012-10-05

A rapid and general access to diversely substituted 5-alkoxyoxazoles 2 (i.e., R(1), R(2) = alkyl, phenyl) from easily accessible α-triflyloxy/hydroxy esters 1 and nitriles with good yields (41-76%) is reported. The versatility of the cyclization is shown for a range of substrates with high selectivity toward triflates over mesylates and proved to be compatible with sensitive functional groups. As an illustration of this transformation, the first synthesis of the recently isolated hydroxypyridine methyl multijuguinate 4 was achieved in four steps through a hetero Diels-Alder reaction of the 5-alkoxyoxazole and acrylic acid, followed by a protodecarboxylation reaction.

Sensation seeking, augmenting-reducing, and absolute auditory threshold: a strength-of-the-nervous-system perspective.

PubMed

Goldman, D; Kohn, P M; Hunt, R W

1983-08-01

The following measures were obtained from 42 student volunteers: the General and the Disinhibition subscales of the Sensation Seeking Scale (Form IV), the Reducer-Augmenter Scale, and the Absolute Auditory Threshold. General sensation seeking correlated significantly with the Reducer-Augmenter Scale, r(40) = .59, p less than .001, and the Absolute Auditory Threshold, r(40) = .45, p less than .005. Both results proved general across sex. These findings, that high-sensation seekers tend to be reducers and to lack sensitivity to weak stimulation, were interpreted as supporting strength-of-the-nervous-system theory more than the formulation of Zuckerman and his associates.

Switching assay as a novel approach for specific antigen- antibody interaction analysis using magnetic nanoparticles

NASA Astrophysics Data System (ADS)

Parr, M.; Illarionov, R.; Marchenko, Y.; Yakovleva, L.; Nikolaev, B.; Ischenko, A.; Shevtsov, M.

2016-08-01

Switching assay was applied for the detection of antigen-antibody interaction between 70-kDa heat shock protein (Hsp70) and anti-Hsp70 monoclonal antibodies in water solutions using conjugates with magnetic iron oxide nanoparticles (MNPs). Hsp70 is a ubiquitous intracellular protein that plays a crucial role in cancerogenesis and many other pathologies. Detection of the Hsp70 level in the biological fluids might have a prognostic and diagnostic value in clinic. The developed switch assay for the detection of Hsp70 demonstrated high sensitivity for antigen-antibody interaction analysis thus proving its potential for further preclinical and clinical studies.

The use of capillary electrophoresis as part of a specificity testing strategy for mitoguazone dihydrochloride HPLC methods.

PubMed

Thomson, C E; Gray, M R; Baxter, M P

1997-05-01

Capillary electrophoresis (CE) has been used as part of a validation experiment designed to prove the specificity of high performance liquid chromatography (HPLC) methods used for analysis of mitoguazone dihydrochloride drug substance. Data regarding accuracy, precision and sensitivity of the CE methods are presented as well as a comparison of results obtained from CE, HPLC and thin-layer chromatography (TLC) analysis of samples stressed under a variety of conditions. It was concluded that, not only were the HPLC methods being investigated specific, but that CE could potentially be used to replace HPLC for the routine assay of mitoguazone dihydrochloride.

A high-throughput liquid bead array-based screening technology for Bt presence in GMO manipulation.

PubMed

Fu, Wei; Wang, Huiyu; Wang, Chenguang; Mei, Lin; Lin, Xiangmei; Han, Xueqing; Zhu, Shuifang

2016-03-15

The number of species and planting areas of genetically modified organisms (GMOs) has been rapidly developed during the past ten years. For the purpose of GMO inspection, quarantine and manipulation, we have now devised a high-throughput Bt-based GMOs screening method based on the liquid bead array. This novel method is based on the direct competitive recognition between biotinylated antibodies and beads-coupled antigens, searching for Bt presence in samples if it contains Bt Cry1 Aa, Bt Cry1 Ab, Bt Cry1 Ac, Bt Cry1 Ah, Bt Cry1 B, Bt Cry1 C, Bt Cry1 F, Bt Cry2 A, Bt Cry3 or Bt Cry9 C. Our method has a wide GMO species coverage so that more than 90% of the whole commercialized GMO species can be identified throughout the world. Under our optimization, specificity, sensitivity, repeatability and availability validation, the method shows a high specificity and 10-50 ng/mL sensitivity of quantification. We then assessed more than 1800 samples in the field and food market to prove capacity of our method in performing a high throughput screening work for GMO manipulation. Our method offers an applicant platform for further inspection and research on GMO plants. Copyright © 2015 Elsevier B.V. All rights reserved.

Rapid and specific detection of Salmonella in water samples using real-time PCR and High Resolution Melt (HRM) curve analysis.

PubMed

van Blerk, G N; Leibach, L; Mabunda, A; Chapman, A; Louw, D

2011-01-01

A real-time PCR assay combined with a pre-enrichment step for the specific and rapid detection of Salmonella in water samples is described. Following amplification of the invA gene target, High Resolution Melt (HRM) curve analysis was used to discriminate between products formed and to positively identify invA amplification. The real-time PCR assay was evaluated for specificity and sensitivity. The assay displayed 100% specificity for Salmonella and combined with a 16-18 h non-selective pre-enrichment step, the assay proved to be highly sensitive with a detection limit of 1.0 CFU/ml for surface water samples. The detection assay also demonstrated a high intra-run and inter-run repeatability with very little variation in invA amplicon melting temperature. When applied to water samples received routinely by the laboratory, the assay showed the presence of Salmonella in particularly surface water and treated effluent samples. Using the HRM based assay, the time required for Salmonella detection was drastically shortened to less than 24 h compared to several days when using standard culturing methods. This assay provides a useful tool for routine water quality monitoring as well as for quick screening during disease outbreaks.

Amine dependence of proliferative activity in two transplantable lines of mouse colonic carcinoma.

PubMed

Tutton, P J; Barkla, D H

1987-01-01

Serotonin, histamine and their antagonists have previously been shown to influence both the cell proliferation rate and the volumetric growth rate of colonic tumours. Of these earlier studies, those on cell proliferation could not distinguish between direct effects on tumour cells and indirect effects on the host, whereas those on the volumetric growth rate of tumours, whilst suggesting an outcome related to the individual properties of the tumour rather than the host, could not distinguish between influences on cell gain, cell loss or stromal changes. In an attempt to distinguish between these possibilities the current experiments on the mitotic rate in two lines of transplantable mouse colonic carcinoma were undertaken. One line of tumour proved to be sensitive to inhibition by a histamine H2 receptor antagonist and a dopamine D2 antagonist but resistant to serotonin antagonists; the inhibition by histamine antagonists was surmountable by co-administration of histamine. The other line proved to be highly sensitive to the inhibitory effects of serotonin antagonist and less so to antagonists of the other two amines and in this case the effect of serotonin antagonists was surmountable by serotonin. These results suggest that the variations between different colonic tumours in the response to amine antagonists is due to differences in the extent of inhibition of cell proliferation rather than differences in cell loss or stromal effects. Thus it appears likely that amine antagonists are able to directly interfere with the proliferation of some colonic tumour cells.

Genesis analysis of high-gamma ray sandstone reservoir and its log evaluation techniques: a case study from the Junggar basin, northwest China.

PubMed

Wang, Liang; Mao, Zhiqiang; Sun, Zhongchun; Luo, Xingping; Song, Yong; Liu, Zhen

2013-01-01

In the Junggar basin, northwest China, many high gamma-ray (GR) sandstone reservoirs are found and routinely interpreted as mudstone non-reservoirs, with negative implications for the exploration and exploitation of oil and gas. Then, the high GR sandstone reservoirs' recognition principles, genesis, and log evaluation techniques are systematically studied. Studies show that the sandstone reservoirs with apparent shale content greater than 50% and GR value higher than 110API can be regarded as high GR sandstone reservoir. The high GR sandstone reservoir is mainly and directly caused by abnormally high uranium enrichment, but not the tuff, feldspar or clay mineral. Affected by formation's high water sensitivity and poor borehole quality, the conventional logs can not recognize reservoir and evaluate the physical property of reservoirs. Then, the nuclear magnetic resonance (NMR) logs is proposed and proved to be useful in reservoir recognition and physical property evaluation.

Genesis Analysis of High-Gamma Ray Sandstone Reservoir and Its Log Evaluation Techniques: A Case Study from the Junggar Basin, Northwest China

PubMed Central

Wang, Liang; Mao, Zhiqiang; Sun, Zhongchun; Luo, Xingping; Song, Yong; Liu, Zhen

2013-01-01

In the Junggar basin, northwest China, many high gamma-ray (GR) sandstone reservoirs are found and routinely interpreted as mudstone non-reservoirs, with negative implications for the exploration and exploitation of oil and gas. Then, the high GR sandstone reservoirs' recognition principles, genesis, and log evaluation techniques are systematically studied. Studies show that the sandstone reservoirs with apparent shale content greater than 50% and GR value higher than 110API can be regarded as high GR sandstone reservoir. The high GR sandstone reservoir is mainly and directly caused by abnormally high uranium enrichment, but not the tuff, feldspar or clay mineral. Affected by formation's high water sensitivity and poor borehole quality, the conventional logs can not recognize reservoir and evaluate the physical property of reservoirs. Then, the nuclear magnetic resonance (NMR) logs is proposed and proved to be useful in reservoir recognition and physical property evaluation. PMID:24078797

Outcompeting nitrite-oxidizing bacteria in single-stage nitrogen removal in sewage treatment plants: a model-based study.

PubMed

Pérez, Julio; Lotti, Tommaso; Kleerebezem, Robbert; Picioreanu, Cristian; van Loosdrecht, Mark C M

2014-12-01

This model-based study investigated the mechanisms and operational window for efficient repression of nitrite oxidizing bacteria (NOB) in an autotrophic nitrogen removal process. The operation of a continuous single-stage granular sludge process was simulated for nitrogen removal from pretreated sewage at 10 °C. The effects of the residual ammonium concentration were explicitly analyzed with the model. Competition for oxygen between ammonia-oxidizing bacteria (AOB) and NOB was found to be essential for NOB repression even when the suppression of nitrite oxidation is assisted by nitrite reduction by anammox (AMX). The nitrite half-saturation coefficient of NOB and AMX proved non-sensitive for the model output. The maximum specific growth rate of AMX bacteria proved a sensitive process parameter, because higher rates would provide a competitive advantage for AMX. Copyright © 2014 Elsevier Ltd. All rights reserved.

Synthesis and antimalarial activity of new chloroquine analogues carrying a multifunctional linear side chain.

PubMed

Iwaniuk, Daniel P; Whetmore, Eric D; Rosa, Nicholas; Ekoue-Kovi, Kekeli; Alumasa, John; de Dios, Angel C; Roepe, Paul D; Wolf, Christian

2009-09-15

We report the synthesis and in vitro antimalarial activity of several new 4-amino- and 4-alkoxy-7-chloroquinolines carrying a linear dibasic side chain. Many of these chloroquine analogues have submicromolar antimalarial activity versus HB3 (chloroquine sensitive) and Dd2 (chloroquine resistant strain of Plasmodium falciparum) and low resistance indices were obtained in most cases. Importantly, compounds 11-15 and 24 proved to be more potent against Dd2 than chloroquine. Branching of the side chain structure proved detrimental to the activity against the CQR strain.

Evaluation of two sterically directed attachments of biomolecules on a coaxial nanofibre membrane to improve the development of optical biosensors.

PubMed

Ramon-Marquez, Teresa; Medina-Castillo, Antonio L; Fernandez-Gutierrez, Alberto; Fernandez-Sanchez, Jorge F

2018-09-01

In this study, we have optimised the sterically directed attachment of biomolecules on the surface of coaxial membranes prepared by co-electrospinning which have been proved to be a material with very high performance for the development of biosensors with optical oxygen transduction. Uricase has been used as model enzyme. Two sterically directed strategies: a) covalent attachment via maleimide, and b) affinity bonding via biotin-streptavidin interaction, have been tested in order to preserve the enzymatic activity of uricase and to improve the analytical figures of merits on the determination of uric acid. The best results were obtained with biotin-streptavidin affinity interaction and using a biotinylation reagent containing a polyethylene glycol chain. The developed biosensor showed high sensitivity towards uric acid with a detection limit of 0.5 µM, a quantification limit of 1.8 µM and linear range from 1.8 to 250 µM. The applicability of the membrane as biosensor with optical oxygen transduction was proved by determining uric acid in serum samples. The obtained results showed a good correlation (0.999) with those obtained by an external reference laboratory. Copyright © 2018 Elsevier B.V. All rights reserved.

Screening for hypochondriasis with the Illness Attitude Scales.

PubMed

Weck, Florian; Bleichhardt, Gaby; Hiller, Wolfgang

2010-05-01

The Illness Attitude Scales (IAS; Kellner, 1986, 1987) may prove highly useful for the screening of hypochondriasis. We expected the IAS subscales to be equally as effective as the 7-item short version of the Whiteley Index (Whiteley-7; Fink et al., 1999), which has previously been shown to be useful in screening for somatoform disorders. We investigated participants of a German population (n = 1,575) and 61 patients with the Diagnostic and Statistical Manual of Mental Disorders (4th ed. [DSM-IV]; American Psychiatric Association, 1994) diagnosis of hypochondriasis. The Bodily Preoccupations (BP) subscale showed high sensitivity (.92) and specificity (.90) as well as demonstrating convergent and discriminant validity. We found evidence for the superiority of the BP subscale over the Whiteley-7 in the screening of hypochondriasis.

Background radiation measurements at high power research reactors

NASA Astrophysics Data System (ADS)

Ashenfelter, J.; Balantekin, B.; Baldenegro, C. X.; Band, H. R.; Barclay, G.; Bass, C. D.; Berish, D.; Bowden, N. S.; Bryan, C. D.; Cherwinka, J. J.; Chu, R.; Classen, T.; Davee, D.; Dean, D.; Deichert, G.; Dolinski, M. J.; Dolph, J.; Dwyer, D. A.; Fan, S.; Gaison, J. K.; Galindo-Uribarri, A.; Gilje, K.; Glenn, A.; Green, M.; Han, K.; Hans, S.; Heeger, K. M.; Heffron, B.; Jaffe, D. E.; Kettell, S.; Langford, T. J.; Littlejohn, B. R.; Martinez, D.; McKeown, R. D.; Morrell, S.; Mueller, P. E.; Mumm, H. P.; Napolitano, J.; Norcini, D.; Pushin, D.; Romero, E.; Rosero, R.; Saldana, L.; Seilhan, B. S.; Sharma, R.; Stemen, N. T.; Surukuchi, P. T.; Thompson, S. J.; Varner, R. L.; Wang, W.; Watson, S. M.; White, B.; White, C.; Wilhelmi, J.; Williams, C.; Wise, T.; Yao, H.; Yeh, M.; Yen, Y.-R.; Zhang, C.; Zhang, X.; Prospect Collaboration

2016-01-01

Research reactors host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these facilities necessitates a detailed understanding of background radiation fields. Both reactor-correlated and naturally occurring background sources are potentially important, even at levels well below those of importance for typical activities. Here we describe a comprehensive series of background assessments at three high-power research reactors, including γ-ray, neutron, and muon measurements. For each facility we describe the characteristics and identify the sources of the background fields encountered. The general understanding gained of background production mechanisms and their relationship to facility features will prove valuable for the planning of any sensitive measurement conducted therein.

From Sour Grapes to Low-Hanging Fruit: A Case Study Demonstrating a Practical Strategy for Natural Language Processing Portability.

PubMed

Johnson, Stephen B; Adekkanattu, Prakash; Campion, Thomas R; Flory, James; Pathak, Jyotishman; Patterson, Olga V; DuVall, Scott L; Major, Vincent; Aphinyanaphongs, Yindalon

2018-01-01

Natural Language Processing (NLP) holds potential for patient care and clinical research, but a gap exists between promise and reality. While some studies have demonstrated portability of NLP systems across multiple sites, challenges remain. Strategies to mitigate these challenges can strive for complex NLP problems using advanced methods (hard-to-reach fruit), or focus on simple NLP problems using practical methods (low-hanging fruit). This paper investigates a practical strategy for NLP portability using extraction of left ventricular ejection fraction (LVEF) as a use case. We used a tool developed at the Department of Veterans Affair (VA) to extract the LVEF values from free-text echocardiograms in the MIMIC-III database. The approach showed an accuracy of 98.4%, sensitivity of 99.4%, a positive predictive value of 98.7%, and F-score of 99.0%. This experience, in which a simple NLP solution proved highly portable with excellent performance, illustrates the point that simple NLP applications may be easier to disseminate and adapt, and in the short term may prove more useful, than complex applications.

[Drugs and occupational accident].

PubMed

Bratzke, H; Albers, C

1996-02-01

In a case of a fatal occupational accident (construction worker, fall from roof, urine test positive for cocaine and THC, e.g. cannabis) the question arised to what extent those drug-related occupational accidents occur. In the literature only few cases, mainly dealing with cannabis influence, have been reported, however, a higher number is suspected. Cocaine and other stimulating drugs (amphetamine) are more often used to increase physical fitness. By direct or indirect interference with vigilance these compounds may provoke accidents. Due to the lack of a legal basis proving of the influence of drugs at the working place is still very limited, although highly sensitive chemical-toxicological assay procedures are available to detect even the chronic abuse (in hair). In the general conditions of accident insurances a compensation is excluded when alcohol is involved, but drugs are not mentioned. It is indeed difficult to establish a concentration limit for drugs like that existing for alcohol (1.1%). In each case the assay of the drug involved and exact knowledge of its specific effects is in an essential prerequisite to prove the causal relationship.

Setup for testing cameras for image guided surgery using a controlled NIR fluorescence mimicking light source and tissue phantom

NASA Astrophysics Data System (ADS)

Georgiou, Giota; Verdaasdonk, Rudolf M.; van der Veen, Albert; Klaessens, John H.

2017-02-01

In the development of new near-infrared (NIR) fluorescence dyes for image guided surgery, there is a need for new NIR sensitive camera systems that can easily be adjusted to specific wavelength ranges in contrast the present clinical systems that are only optimized for ICG. To test alternative camera systems, a setup was developed to mimic the fluorescence light in a tissue phantom to measure the sensitivity and resolution. Selected narrow band NIR LED's were used to illuminate a 6mm diameter circular diffuse plate to create uniform intensity controllable light spot (μW-mW) as target/source for NIR camera's. Layers of (artificial) tissue with controlled thickness could be placed on the spot to mimic a fluorescent `cancer' embedded in tissue. This setup was used to compare a range of NIR sensitive consumer's cameras for potential use in image guided surgery. The image of the spot obtained with the cameras was captured and analyzed using ImageJ software. Enhanced CCD night vision cameras were the most sensitive capable of showing intensities < 1 μW through 5 mm of tissue. However, there was no control over the automatic gain and hence noise level. NIR sensitive DSLR cameras proved relative less sensitive but could be fully manually controlled as to gain (ISO 25600) and exposure time and are therefore preferred for a clinical setting in combination with Wi-Fi remote control. The NIR fluorescence testing setup proved to be useful for camera testing and can be used for development and quality control of new NIR fluorescence guided surgery equipment.

A Practical Model of Quartz Crystal Microbalance in Actual Applications.

PubMed

Huang, Xianhe; Bai, Qingsong; Hu, Jianguo; Hou, Dong

2017-08-03

A practical model of quartz crystal microbalance (QCM) is presented, which considers both the Gaussian distribution characteristic of mass sensitivity and the influence of electrodes on the mass sensitivity. The equivalent mass sensitivity of 5 MHz and 10 MHz AT-cut QCMs with different sized electrodes were calculated according to this practical model. The equivalent mass sensitivity of this practical model is different from the Sauerbrey's mass sensitivity, and the error between them increases sharply as the electrode radius decreases. A series of experiments which plate rigid gold film onto QCMs were carried out and the experimental results proved this practical model is more valid and correct rather than the classical Sauerbrey equation. The practical model based on the equivalent mass sensitivity is convenient and accurate in actual measurements.

Low angle light scattering analysis: a novel quantitative method for functional characterization of human and murine platelet receptors.

PubMed

Mindukshev, Igor; Gambaryan, Stepan; Kehrer, Linda; Schuetz, Claudia; Kobsar, Anna; Rukoyatkina, Natalia; Nikolaev, Viacheslav O; Krivchenko, Alexander; Watson, Steve P; Walter, Ulrich; Geiger, Joerg

2012-07-01

Determinations of platelet receptor functions are indispensable diagnostic indicators of cardiovascular and hemostatic diseases including hereditary and acquired receptor defects and receptor responses to drugs. However, presently available techniques for assessing platelet function have some disadvantages, such as low sensitivity and the requirement of large sample sizes and unphysiologically high agonist concentrations. Our goal was to develop and initially characterize a new technique designed to quantitatively analyze platelet receptor activation and platelet function on the basis of measuring changes in low angle light scattering. We developed a novel technique based on low angle light scattering registering changes in light scattering at a range of different angles in platelet suspensions during activation. The method proved to be highly sensitive for simultaneous real time detection of changes in size and shape of platelets during activation. Unlike commonly-used methods, the light scattering method could detect platelet shape change and aggregation in response to nanomolar concentrations of extracellular nucleotides. Furthermore, our results demonstrate that the advantages of the light scattering method make it a choice method for platelet receptor monitoring and for investigation of both murine and human platelets in disease models. Our data demonstrate the suitability and superiority of this new low angle light scattering method for comprehensive analyses of platelet receptors and functions. This highly sensitive, quantitative, and online detection of essential physiological, pathophysiological and pharmacological-response properties of human and mouse platelets is a significant improvement over conventional techniques.

Qualitative Determination of Nitrate with Triphenylbenzylphosphonium Chloride.

ERIC Educational Resources Information Center

Berry, Donna A.; Cole, Jerry J.

1984-01-01

Discusses two procedures for the identification of nitrate, the standard test ("Brown Ring" test) and a new procedure using triphenylbenzylphosphonium chloride (TPBPC). Effectiveness of both procedures is compared, with the TPBPC test proving to be more sensitive and accurate. (JM)

Use of the Photo-Electromyogram to Objectively Diagnose and Monitor Treatment of Post-TBI Light Sensitivity

DTIC Science & Technology

2015-10-01

already been well characterized. Finally, we have also been recruiting migraine patients since they commonly report light sensitivity between headaches...and have been recruiting migraine subjects in the immediate 25-mile radius using email announcements and also the UIHC database by diagnostic...expression of pain from feigned pain as might occur when monitoring photosensitivity for migraine treatment. 3D also proves its value for expressions of

Performance evaluation of D-SPECT: a novel SPECT system for nuclear cardiology

NASA Astrophysics Data System (ADS)

Erlandsson, Kjell; Kacperski, Krzysztof; van Gramberg, Dean; Hutton, Brian F.

2009-05-01

D-SPECT (Spectrum Dynamics, Israel) is a novel SPECT system for cardiac perfusion studies. Based on CZT detectors, region-centric scanning, high-sensitivity collimators and resolution recovery, it offers potential advantages over conventional systems. A series of measurements were made on a β-version D-SPECT system in order to evaluate its performance in terms of energy resolution, scatter fraction, sensitivity, count rate capability and resolution. Corresponding measurements were also done on a conventional SPECT system (CS) for comparison. The energy resolution of the D-SPECT system at 140 keV was 5.5% (CS: 9.25%), the scatter fraction 30% (CS: 34%), the planar sensitivity 398 s-1 MBq-1 per head (99mTc, 10 cm) (CS: 72 s-1 MBq-1), and the tomographic sensitivity in the heart region was in the range 647-1107 s-1 MBq-1 (CS: 141 s-1 MBq-1). The count rate increased linearly with increasing activity up to 1.44 M s-1. The intrinsic resolution was equal to the pixel size, 2.46 mm (CS: 3.8 mm). The average reconstructed resolution using the standard clinical filter was 12.5 mm (CS: 13.7 mm). The D-SPECT has superior sensitivity to that of a conventional system with similar spatial resolution. It also has excellent energy resolution and count rate characteristics, which should prove useful in dynamic and dual radionuclide studies.

Celiac disease, wheat allergy, and gluten sensitivity: when gluten free is not a fad.

PubMed

Pietzak, Michelle

2012-01-01

As the gluten-free diet (GFD) gains in popularity with the general public, health practitioners are beginning to question its real health benefits. For those patients with celiac disease (CD), the GFD is considered medical nutrition therapy, as well as the only proven treatment that results in improvements in symptomatology and small bowel histology. Those with wheat allergy also benefit from the GFD, although these patients often do not need to restrict rye, barley, and oats from their diet. Gluten sensitivity is a controversial subject, where patients who have neither CD nor wheat allergy have varying degrees of symptomatic improvement on the GFD. Conditions in this category include dermatitis herpetiformis (DH), irritable bowel syndrome (IBS), and neurologic diseases such as gluten-sensitive ataxia and autism. It is important for patients and healthcare practitioners to understand the differences between these conditions, even though they may all respond to a GFD. Patients with CD can experience comorbid nutrition deficiencies and are at higher risk for the development of cancers and other autoimmune conditions. Those with wheat allergy and gluten sensitivity are thought not to be at higher risk for these complications. Defining the symptoms and biochemical markers for gluten-sensitive conditions is an important area for future investigations, and high-quality, large-scale randomized trials are needed to prove the true benefits of the GFD in this evolving field.

Photonic crystal enhanced fluorescence immunoassay on diatom biosilica.

PubMed

Squire, Kenneth; Kong, Xianming; LeDuff, Paul; Rorrer, Gregory L; Wang, Alan X

2018-05-16

Fluorescence biosensing is one of the most established biosensing methods, particularly fluorescence spectroscopy and microscopy. These are two highly sensitive techniques but require high grade electronics and optics to achieve the desired sensitivity. Efforts have been made to implement these methods using consumer grade electronics and simple optical setups for applications such as point-of-care diagnostics, but the sensitivity inherently suffers. Sensing substrates, capable of enhancing fluorescence are thus needed to achieve high sensitivity for such applications. In this paper, we demonstrate a photonic crystal-enhanced fluorescence immunoassay biosensor using diatom biosilica, which consists of silica frustules with sub-100 nm periodic pores. Utilizing the enhanced local optical field, the Purcell effect and increased surface area from the diatom photonic crystals, we create ultrasensitive immunoassay biosensors that can significantly enhance fluorescence spectroscopy as well as fluorescence imaging. Using standard antibody-antigen-labeled antibody immunoassay protocol, we experimentally achieved 100× and 10× better detection limit with fluorescence spectroscopy and fluorescence imaging respectively. The limit of detection of the mouse IgG goes down to 10 -16 M (14 fg/mL) and 10 -15 M (140 fg/mL) for the two respective detection modalities, virtually sensing a single mouse IgG molecule on each diatom frustule. The effectively enhanced fluorescence imaging in conjunction with the simple hot-spot counting analysis method used in this paper proves the great potential of diatom fluorescence immunoassay for point-of-care biosensing. Scanning electron microscope image of biosilica diatom frustule that enables significant enhancement of fluorescence spectroscopy and fluorescence image. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

High-sensitive electrochemical detection of point mutation based on polymerization-induced enzymatic amplification.

PubMed

Feng, Kejun; Zhao, Jingjin; Wu, Zai-Sheng; Jiang, Jianhui; Shen, Guoli; Yu, Ruqin

2011-03-15

Here a highly sensitive electrochemical method is described for the detection of point mutation in DNA. Polymerization extension reaction is applied to specifically initiate enzymatic electrochemical amplification to improve the sensitivity and enhance the performance of point mutation detection. In this work, 5'-thiolated DNA probe sequences complementary to the wild target DNA are assembled on the gold electrode. In the presence of wild target DNA, the probe is extended by DNA polymerase over the free segment of target as the template. After washing with NaOH solution, the target DNA is removed while the elongated probe sequence remains on the sensing surface. Via hybridizing to the designed biotin-labeled detection probe, the extended sequence is capable of capturing detection probe. After introducing streptavidin-conjugated alkaline phosphatase (SA-ALP), the specific binding between streptavidin and biotin mediates a catalytic reaction of ascorbic acid 2-phosphate (AA-P) substrate to produce a reducing agent ascorbic acid (AA). Then the silver ions in solution are reduced by AA, leading to the deposition of silver metal onto the electrode surface. The amount of deposited silver which is determined by the amount of wild target can be quantified by the linear sweep voltammetry (LSV). The present approach proved to be capable of detecting the wild target DNA down to a detection limit of 1.0×10(-14) M in a wide target concentration range and identifying -28 site (A to G) of the β-thalassemia gene, demonstrating that this scheme offers a highly sensitive and specific approach for point mutation detection. Copyright © 2010 Elsevier B.V. All rights reserved.

PAX1 methylation analysis by MS-HRM is useful in triage of high-grade squamous intraepithelial lesions.

PubMed

Wang, Zhen-Ming

2014-01-01

This study is aimed to investigate the role of paired boxed gene 1 (PAX1) methylation analysis by methylation- sensitive high-resolution melting (MS-HRM) in the detection of high grade lesions in atypical squamous cells cannot exclude high-grade squamous intraepithelial lesion (ASC-H) and compared its performance with the Hybrid Capture 2 (HC2) human papillomavirus (HPV) test. In our study, 130 cases with a diagnosis of ASC-H from the cervical cytological screening by Thinprep cytologic test (TCT) technique were selected for triage. Their cervical scrapings were collected and evaluated by using PAX1 methylation analysis (MS-HRM) and high-risk HPV DNA test (HC2), followed by colposcopy and cervical biopsy. Chi-square test were used to test the differences of PAX1 methylation or HPV infection between groups. In the detection of CIN2+, the sensitivity, specificity, the PPV, NPV and the accuracy of PAX1 MS-HRM assay and high-risk HPV (HR-HPV) tests were respectively 80.6% vs 67.7%, 94.9% vs 54.5%, 83.3%, vs 31.8%, 94.0% vs 84.4%, and 91.5% vs 57.7%. The PAX1 MS-HRM assay proved superior to HR-HPV testing in the detection of high grade lesions (CIN2+) in ASC-H. This approach could screen out the majority of high grade lesion cases of ASC-H, and thus could reduce the referral rate to colposcopy.

High performance of a new PCR-based urine assay for HPV-DNA detection and genotyping.

PubMed

Tanzi, Elisabetta; Bianchi, Silvia; Fasolo, Maria Michela; Frati, Elena R; Mazza, Francesca; Martinelli, Marianna; Colzani, Daniela; Beretta, Rosangela; Zappa, Alessandra; Orlando, Giovanna

2013-01-01

Human papillomavirus (HPV) testing has been proposed as a means of replacing or supporting conventional cervical screening (Pap test). However, both methods require the collection of cervical samples. Urine sample is easier and more acceptable to collect and could be helpful in facilitating cervical cancer screening. The aim of this study was to evaluate the sensitivity and specificity of urine testing compared to conventional cervical smear testing using a PCR-based method with a new, designed specifically primer set. Paired cervical and first voided urine samples collected from 107 women infected with HIV were subjected to HPV-DNA detection and genotyping using a PCR-based assay and a restriction fragment length polymorphism method. Sensitivity, specificity, Positive Predictive Value (PPV), and Negative Predictive Value (NPV) were calculated using the McNemar's test for differences. Concordance between tests was assessed using the Cohen's unweighted Kappa (k). HPV DNA was detected in 64.5% (95% CI: 55.1-73.1%) of both cytobrush and urine samples. High concordance rates of HPV-DNA detection (k = 0.96; 95% CI: 0.90-1.0) and of high risk-clade and low-risk genotyping in paired samples (k = 0.80; 95% CI: 0.67-0.92 and k = 0.74; 95% CI: 0.60-0.88, respectively) were observed. HPV-DNA detection in urine versus cervix testing revealed a sensitivity of 98.6% (95% CI: 93.1-99.9%) and a specificity of 97.4% (95% CI: 87.7-99.9%), with a very high NPV (97.4%; 95% CI: 87.7-99.9%). The PCR-based assay utilized in this study proved highly sensitive and specific for HPV-DNA detection and genotyping in urine samples. These data suggest that a urine-based assay would be a suitable and effective tool for epidemiological surveillance and, most of all, screening programs. Copyright © 2012 Wiley Periodicals, Inc.

Schottky-contact plasmonic dipole rectenna concept for biosensing.

PubMed

Alavirad, Mohammad; Mousavi, Saba Siadat; Roy, Langis; Berini, Pierre

2013-02-25

Nanoantennas are key optical components for several applications including photodetection and biosensing. Here we present an array of metal nano-dipoles supporting surface plasmon polaritons (SPPs) integrated into a silicon-based Schottky-contact photodetector. Incident photons coupled to the array excite SPPs on the Au nanowires of the antennas which decay by creating "hot" carriers in the metal. The hot carriers may then be injected over the potential barrier at the Au-Si interface resulting in a photocurrent. High responsivities of 100 mA/W and practical minimum detectable powers of -12 dBm should be achievable in the infra-red (1310 nm). The device was then investigated for use as a biosensor by computing its bulk and surface sensitivities. Sensitivities of ∼ 250 nm/RIU (bulk) and ∼ 8 nm/nm (surface) in water are predicted. We identify the mode propagating and resonating along the nanowires of the antennas, we apply a transmission line model to describe the performance of the antennas, and we extract two useful formulas to predict their bulk and surface sensitivities. We prove that the sensitivities of dipoles are much greater than those of similar monopoles and we show that this difference comes from the gap in dipole antennas where electric fields are strongly enhanced.

Folate-containing reduction-sensitive lipid-polymer hybrid nanoparticles for targeted delivery of doxorubicin.

PubMed

Wu, Bo; Yu, Ping; Cui, Can; Wu, Ming; Zhang, Yang; Liu, Lei; Wang, Cai-Xia; Zhuo, Ren-Xi; Huang, Shi-Wen

2015-04-01

The development and evaluation of folate-targeted and reduction-triggered biodegradable nanoparticles are introduced to the research on targeted delivery of doxorubicin (DOX). This type of folate-targeted lipid-polymer hybrid nanoparticles (FLPNPs) is comprised of a poly(D,L-lactide-co-glycolide) (PLGA) core, a soybean lecithin monolayer, a monomethoxy-poly(ethylene glycol)-S-S-hexadecyl (mPEG-S-S-C16) reduction-sensitive shell, and a folic acid-targeted ligand. FLPNPs exhibited high size stability but fast disassembly in a simulated cancer cell reductive environment. The experiments on the release process in vitro revealed that as a reduction-sensitive drug delivery system, FLPNPs released DOX faster in the presence of 10 mM dithiothreitol (DTT). Results from flow cytometry, confocal image and in vitro cytotoxicity assays revealed that FLPNPs further enhanced cell uptake and generated higher cytotoxicity against human epidermoid carcinoma in the oral cavity than non-targeted redox-sensitive and targeted redox-insensitive controls. Furthermore, in vivo animal experiments demonstrated that systemic administration of DOX-loaded FLPNPs remarkably reduced tumor growth. Experiments on biodistribution of DOX-loaded FLPNPs showed that an increasing amount of DOX accumulated in the tumor. Therefore, FLPNPs formulations have proved to be a stable, controllable and targeted anticancer drug delivery system.

Poor sanitation and helminth infection protect against skin sensitization in Vietnamese children: A cross-sectional study.

PubMed

Flohr, Carsten; Tuyen, Luc Nguyen; Lewis, Sarah; Quinnell, Rupert; Minh, Truong Tan; Liem, Ho Thanh; Campbell, Jim; Pritchard, David; Hien, Tran Tinh; Farrar, Jeremy; Williams, Hywel; Britton, John

2006-12-01

Geohelminth infection and poor hygiene may be protective against allergic sensitization. To determine whether current helminth infection is associated with a reduced prevalence of allergen skin test sensitization in a Southeast Asian population of children with a high prevalence of hookworm infection. A total of 1742 Vietnamese schoolchildren were invited to take part in a cross-sectional survey. Allergen skin sensitization to house dust mites (Dermatophagoides pteronyssinus and Dermatophagoides farinae) and American cockroach (Periplaneta americana) were measured and stool samples for qualitative and quantitative geohelminth estimation collected. A total of 1601 children age 6 to 18 participated. Sensitization to dust mites was present in 14.4% and to cockroach in 27.6% of children. In a mutually adjusted model, the risk of sensitization to dust mites was reduced in those with higher hookworm burden (adjusted odds ratio [OR] for 350+ vs no eggs per gram, 0.61; 95% CI, 0.39-0.96) and with Ascaris infection (adjusted OR, 0.28; 0.10-0.78), and increased in those using flush toilets (adjusted OR for flush toilet vs none/bush/pit, 2.51; 1.00-6.28). In contrast, sensitization to cockroach was not independently related to geohelminth infection but was increased in those regularly drinking piped or well water rather than from a stream (adjusted OR, 1.33; 1.02-1.75). Geohelminth infection, sanitation, and water supply influence the risk of allergic sensitization in Vietnamese children. This is consistent with a protective effect against allergy by geohelminth or other gastrointestinal infection. If the inverse relationship between geohelminth infection, poor sanitation, and allergic sensitization proves to be causal, drugs derived from parasite products may help to alleviate clinical allergic disease.

Measurement method for roll angular displacement with a high resolution by using diffraction gratings and a heterodyne interferometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Shanzhi, E-mail: shanzhit@gmail.com; School of Mechanical Engineering, Xi'an Jiaotong University, Xi'an 710049; Wang, Zhao

The roll angle measurement is difficult to be achieved directly using a typical commercial interferometer due to its low sensitivity in axial direction, where the axial direction is orthogonal to the plane of the roll angular displacement. A roll angle measurement method combined diffraction gratings with a laser heterodyne interferometer is discussed in this paper. The diffraction grating placed in the plane of a roll angular displacement and the interferometer arranged in the plane's orthogonal direction, constitute the measurement pattern for the roll angle with high resolution. The roll angular displacement, considered as the linear, can be tested precisely whenmore » the corresponding angle is very small. Using the proposed method, the angle roll measurement obtains the high resolution of 0.002{sup ″}. Experiment has proved its feasibility and practicability.« less

Effectiveness and Cost Efficiency of Different Surveillance Components for Proving Freedom and Early Detection of Disease: Bluetongue Serotype 8 in Cattle as Case Study for Belgium, France and the Netherlands.

PubMed

Welby, S; van Schaik, G; Veldhuis, A; Brouwer-Middelesch, H; Peroz, C; Santman-Berends, I M; Fourichon, C; Wever, P; Van der Stede, Y

2017-12-01

Quick detection and recovery of country's freedom status remain a constant challenge in animal health surveillance. The efficacy and cost efficiency of different surveillance components in proving the absence of infection or (early) detection of bluetongue serotype 8 in cattle populations within different countries (the Netherlands, France, Belgium) using surveillance data from years 2006 and 2007 were investigated using an adapted scenario tree model approach. First, surveillance components (sentinel, yearly cross-sectional and passive clinical reporting) within each country were evaluated in terms of efficacy for substantiating freedom of infection. Yearly cross-sectional survey and passive clinical reporting performed well within each country with sensitivity of detection values ranging around 0.99. The sentinel component had a sensitivity of detection around 0.7. Secondly, how effective the components were for (early) detection of bluetongue serotype 8 and whether syndromic surveillance on reproductive performance, milk production and mortality data available from the Netherlands and Belgium could be of added value were evaluated. Epidemic curves were used to estimate the timeliness of detection. Sensitivity analysis revealed that expected within-herd prevalence and number of herds processed were the most influential parameters for proving freedom and early detection. Looking at the assumed direct costs, although total costs were low for sentinel and passive clinical surveillance components, passive clinical surveillance together with syndromic surveillance (based on reproductive performance data) turned out most cost-efficient for the detection of bluetongue serotype 8. To conclude, for emerging or re-emerging vectorborne disease that behaves such as bluetongue serotype 8, it is recommended to use passive clinical and syndromic surveillance as early detection systems for maximum cost efficiency and sensitivity. Once an infection is detected and eradicated, cross-sectional screening for substantiating freedom of infection and sentinel for monitoring the disease evolution are recommended. © 2016 Blackwell Verlag GmbH.

High-Q Wafer Level Package Based on Modified Tri-Layer Anodic Bonding and High Performance Getter and Its Evaluation for Micro Resonant Pressure Sensor.

PubMed

Wang, Liying; Du, Xiaohui; Wang, Lingyun; Xu, Zhanhao; Zhang, Chenying; Gu, Dandan

2017-03-16

In order to achieve and maintain a high quality factor (high-Q) for the micro resonant pressure sensor, this paper presents a new wafer level package by adopting cross-layer anodic bonding technique of the glass/silicon/silica (GSS) stackable structure and integrated Ti getter. A double-layer structure similar to a silicon-on-insulator (SOI) wafer is formed after the resonant layer and the pressure-sensitive layer are bonded by silicon direct bonding (SDB). In order to form good bonding quality between the pressure-sensitive layer and the glass cap layer, the cross-layer anodic bonding technique is proposed for vacuum package by sputtering Aluminum (Al) on the combination wafer of the pressure-sensitive layer and the resonant layer to achieve electrical interconnection. The model and the bonding effect of this technique are discussed. In addition, in order to enhance the performance of titanium (Ti) getter, the prepared and activation parameters of Ti getter under different sputtering conditions are optimized and discussed. Based on the optimized results, the Ti getter (thickness of 300 nm to 500 nm) is also deposited on the inside of the glass groove by magnetron sputtering to maintain stable quality factor (Q). The Q test of the built testing system shows that the number of resonators with a Q value of more than 10,000 accounts for more than 73% of the total. With an interval of 1.5 years, the Q value of the samples remains almost constant. It proves the proposed cross-layer anodic bonding and getter technique can realize high-Q resonant structure for long-term stable operation.

On multi-sensitivity with respect to a vector

NASA Astrophysics Data System (ADS)

Jiao, Lixin; Wang, Lidong; Li, Fengquan; Liu, Heng

2018-05-01

Consider the surjective continuous map f: X → X defined on a compact metric space X. Let 𝒦(X) be the space of all non-empty compact subsets of X equipped with the Hausdorff metric and define f¯: 𝒦(X) →𝒦(X) by f¯(A) = {f(a),a ∈ A} for any A ∈𝒦(X). In this paper, we introduce several stronger versions of sensitivities, such as multi-sensitivity with respect to a vector, 𝒩-sensitivity, strong multi-sensitivity. We obtain some basic properties of the concepts of these sensitivities and discuss the relationships with other sensitivities for continuous self-map on [0,1]. Some sufficient conditions for a dynamical system to be 𝒩-sensitive are presented. Also, it is shown that the strong multi-sensitivity of f implies that f¯ is 𝒩-sensitive. In turn, the 𝒩-sensitivity of f¯ implies that f is 𝒩-sensitive. In particular, it is proved that if f is a multi-transitive map with dense periodic sets, then f is 𝒩-sensitive. Finally, we give a multi-sensitive example which is not 𝒩-sensitive.

Isolated nanoinjection photo detectors for high-speed and high-sensitivity single-photon detection

NASA Astrophysics Data System (ADS)

Fathipour, V.; Memis, O. G.; Jang, S. J.; Khalid, F.; Brown, R. L.; Hassaninia, I.; Gelfand, R.; Mohseni, H.

2013-09-01

Our group has designed and developed a new SWIR single photon detector called the nano-injection detector that is conceptually designed with biological inspirations taken from the rod cells in human eye. The detector couples a nanoscale sensory region with a large absorption volume to provide avalanche free internal amplification while operating at linear regime with low bias voltages. The low voltage operation makes the detector to be fully compatible with available CMOS technologies. Because there is no photon reemission, detectors can be formed into high-density single-photon detector arrays. As such, the nano injection detectors are viable candidates for SPD and imaging at the short-wave infrared band. Our measurements in 2007 proved a high SNR and a stable excess noise factor of near unity. We are reporting on a high speed version of the detector with 4 orders of magnitude enhancement in speed as well as 2 orders of magnitude reduction in dark current (30nA vs. 10 uA at 1.5V).

Deep Whole-Genome Sequencing to Detect Mixed Infection of Mycobacterium tuberculosis

PubMed Central

Gan, Mingyu; Liu, Qingyun; Yang, Chongguang; Gao, Qian; Luo, Tao

2016-01-01

Mixed infection by multiple Mycobacterium tuberculosis (MTB) strains is associated with poor treatment outcome of tuberculosis (TB). Traditional genotyping methods have been used to detect mixed infections of MTB, however, their sensitivity and resolution are limited. Deep whole-genome sequencing (WGS) has been proved highly sensitive and discriminative for studying population heterogeneity of MTB. Here, we developed a phylogenetic-based method to detect MTB mixed infections using WGS data. We collected published WGS data of 782 global MTB strains from public database. We called homogeneous and heterogeneous single nucleotide variations (SNVs) of individual strains by mapping short reads to the ancestral MTB reference genome. We constructed a phylogenomic database based on 68,639 homogeneous SNVs of 652 MTB strains. Mixed infections were determined if multiple evolutionary paths were identified by mapping the SNVs of individual samples to the phylogenomic database. By simulation, our method could specifically detect mixed infections when the sequencing depth of minor strains was as low as 1× coverage, and when the genomic distance of two mixed strains was as small as 16 SNVs. By applying our methods to all 782 samples, we detected 47 mixed infections and 45 of them were caused by locally endemic strains. The results indicate that our method is highly sensitive and discriminative for identifying mixed infections from deep WGS data of MTB isolates. PMID:27391214

Effect of fixation positions on perception of lightness

NASA Astrophysics Data System (ADS)

Toscani, Matteo; Valsecchi, Matteo; Gegenfurtner, Karl R.

2015-03-01

Visual acuity, luminance sensitivity, contrast sensitivity, and color sensitivity are maximal in the fovea and decrease with retinal eccentricity. Therefore every scene is perceived by integrating the small, high resolution samples collected by moving the eyes around. Moreover, when viewing ambiguous figures the fixated position influences the dominance of the possible percepts. Therefore fixations could serve as a selection mechanism whose function is not confined to finely resolve the selected detail of the scene. Here this hypothesis is tested in the lightness perception domain. In a first series of experiments we demonstrated that when observers matched the color of natural objects they based their lightness judgments on objects' brightest parts. During this task the observers tended to fixate points with above average luminance, suggesting a relationship between perception and fixations that we causally proved using a gaze contingent display in a subsequent experiment. Simulations with rendered physical lighting show that higher values in an object's luminance distribution are particularly informative about reflectance. In a second series of experiments we considered a high level strategy that the visual system uses to segment the visual scene in a layered representation. We demonstrated that eye movement sampling mediates between the layer segregation and its effects on lightness perception. Together these studies show that eye fixations are partially responsible for the selection of information from a scene that allows the visual system to estimate the reflectance of a surface.

Pan-arctic trends in terrestrial dissolved organic matter from optical measurements

NASA Astrophysics Data System (ADS)

Mann, Paul; Spencer, Robert; Hernes, Peter; Six, Johan; Aiken, George; Tank, Suzanne; McClelland, James; Butler, Kenna; Dyda, Rachael; Holmes, Robert

2016-03-01

Climate change is causing extensive warming across arctic regions resulting in permafrost degradation, alterations to regional hydrology, and shifting amounts and composition of dissolved organic matter (DOM) transported by streams and rivers. Here, we characterize the DOM composition and optical properties of the six largest arctic rivers draining into the Arctic Ocean to examine the ability of optical measurements to provide meaningful insights into terrigenous carbon export patterns and biogeochemical cycling. The chemical composition of aquatic DOM varied with season, spring months were typified by highest lignin phenol and dissolved organic carbon (DOC) concentrations with greater hydrophobic acid content, and lower proportions of hydrophilic compounds, relative to summer and winter months. Chromophoric DOM (CDOM) spectral slope (S275-295) tracked seasonal shifts in DOM composition across river basins. Fluorescence and parallel factor analysis identified seven components across the six Arctic rivers. The ratios of 'terrestrial humic-like' versus 'marine humic-like' fluorescent components co-varied with lignin monomer ratios over summer and winter months, suggesting fluorescence may provide information on the age and degradation state of riverine DOM. CDOM absorbance (a350) proved a sensitive proxy for lignin phenol concentrations across all six river basins and over the hydrograph, enabling for the first time the development of a single pan-arctic relationship between a350 and terrigenous DOC (R2 = 0.93). Combining this lignin proxy with high-resolution monitoring of a350, pan-arctic estimates of annual lignin flux were calculated to range from 156 to 185 Gg, resulting in shorter and more constrained estimates of terrigenous DOM residence times in the Arctic Ocean (spanning 7 months to 2½ years). Furthermore, multiple linear regression models incorporating both absorbance and fluorescence variables proved capable of explaining much of the variability in lignin composition across rivers and seasons. Our findings suggest that synoptic, high-resolution optical measurements can provide improved understanding of northern high-latitude organic matter cycling and flux, and prove an important technique for capturing future climate-driven changes.

Ethanol-nicotine interactions in long-sleep and short-sleep mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

de Fiebre, C.M.; Marks, M.J.; Collins, A.C.

The possibility that common genetic factors regulate initial sensitivities to ethanol and nicotine as well as the development of cross-tolerance between these agents was explored using the long-sleep (LS) and short-sleep (SS) mice. The LS mice proved to be more sensitive to an acute challenge with nicotine than were the SS mice. Segregation analysis (F1, F2, backcross) indicated that ethanol sensitivity and nicotine sensitivity segregate together. Acute pretreatment with nicotine did not significantly affect sensitivity to ethanol, but ethanol pretreatment altered nicotine responsiveness. The LS mice develop more tolerance to nicotine and ethanol than do the SS and they alsomore » develop more cross-tolerance. These genetically determined differences in initial sensitivities, and tolerance and cross-tolerance development are not readily explained by differences in brain nicotinic receptor numbers.« less

Novel Gyroscopic Mounting for Crystal Oscillators to Increase Short and Medium Term Stability under Highly Dynamic Conditions

PubMed Central

Abedi, Maryam; Jin, Tian; Sun, Kewen

2015-01-01

In this paper, a gyroscopic mounting method for crystal oscillators to reduce the impact of dynamic loads on their output stability has been proposed. In order to prove the efficiency of this mounting approach, each dynamic load-induced instability has been analyzed in detail. A statistical study has been performed on the elevation angle of the g-sensitivity vector of Stress Compensated-cut (SC-cut) crystals. The analysis results show that the proposed gyroscopic mounting method gives good performance for host vehicle attitude changes. A phase noise improvement of 27 dB maximum and 5.7 dB on average can be achieved in the case of steady state loads, while under sinusoidal vibration conditions, the maximum and average phase noise improvement are as high as 24 dB and 7.5 dB respectively. With this gyroscopic mounting method, random vibration-induced phase noise instability is reduced 30 dB maximum and 8.7 dB on average. Good effects are apparent for crystal g-sensitivity vectors with low elevation angle φ and azimuthal angle β. under highly dynamic conditions, indicating the probability that crystal oscillator instability will be significantly reduced by using the proposed mounting approach. PMID:26091393

Non-invasive Differentiation of Kidney Stone Types using X-ray Dark-Field Radiography

PubMed Central

Scherer, Kai; Braig, Eva; Willer, Konstantin; Willner, Marian; Fingerle, Alexander A.; Chabior, Michael; Herzen, Julia; Eiber, Matthias; Haller, Bernhard; Straub, Michael; Schneider, Heike; Rummeny, Ernst J.; Noël, Peter B.; Pfeiffer, Franz

2015-01-01

Treatment of renal calculi is highly dependent on the chemical composition of the stone in question, which is difficult to determine using standard imaging techniques. The objective of this study is to evaluate the potential of scatter-sensitive X-ray dark-field radiography to differentiate between the most common types of kidney stones in clinical practice. Here, we examine the absorption-to-scattering ratio of 118 extracted kidney stones with a laboratory Talbot-Lau Interferometer. Depending on their chemical composition, microscopic growth structure and morphology the various types of kidney stones show strongly varying, partially opposite contrasts in absorption and dark-field imaging. By assessing the microscopic calculi morphology with high resolution micro-computed tomography measurements, we illustrate the dependence of dark-field signal strength on the respective stone type. Finally, we utilize X-ray dark-field radiography as a non-invasive, highly sensitive (100%) and specific (97%) tool for the differentiation of calcium oxalate, uric acid and mixed types of stones, while additionally improving the detectability of radio-lucent calculi. We prove clinical feasibility of the here proposed method by accurately classifying renal stones, embedded within a fresh pig kidney, using dose-compatible measurements and a quick and simple visual inspection. PMID:25873414

Differential detection of pathogenic Yersinia spp. by fluorescence in situ hybridization.

PubMed

Rohde, Alexander; Hammerl, Jens Andre; Appel, Bernd; Dieckmann, Ralf; Al Dahouk, Sascha

2017-04-01

Yersinia enterocolitica, Y. pseudotuberculosis and Y. pestis are pathogens of major medical importance, which are responsible for a considerable number of infections every year. The detection of these species still relies on cultural methods, which are slow, labour intensive and often hampered by the presence of high amounts of accompanying flora. In this study, fluorescence in situ hybridization (FISH) was used to develop a fast, sensitive and reliable alternative to detect viable bacteria in food. For this purpose, highly specific probes targeting the 16S and 23S ribosomal RNA were employed to differentially detect each of the three species. In order to enable the differentiation of single nucleotide polymorphisms (SNPs), suitable competitor oligonucleotides and locked nucleic acids (LNAs) were used. Starved cells still showed a strong signal and a direct viable count (DVC) approach combined with FISH optimized live/dead discrimination. Sensitivity of the FISH test was high and even a single cell per gram of spiked minced pork meat could be detected within a day, demonstrating the applicability to identify foodborne hazards at an early stage. In conclusion, the established FISH tests proved to be promising tools to compensate existing drawbacks of the conventional cultural detection of these important zoonotic agents. Copyright © 2016 Elsevier Ltd. All rights reserved.

Synthesis and antimalarial activity of new chloroquine analogues carrying a multifunctional linear side chain

PubMed Central

Iwaniuk, Daniel P.; Whetmore, Eric D.; Rosa, Nicholas; Ekoue-Kovi, Kekeli; Alumasa, John; de Dios, Angel C.; Roepe, Paul D.; Wolf, Christian

2009-01-01

We report the synthesis and in vitro antimalarial activity of several new 4-amino-and 4-alkoxy-7-chloroquinolines carrying a linear dibasic side chain. Many of these chloroquine analogues have submicromolar antimalarial activity versus HB3 (chloroquine sensitive) and Dd2 (chloroquine resistant strain of P. falciparum) and low resistance indices were obtained in most cases. Importantly, compounds 11–15 and 24 proved to be more potent against Dd2 than chloroquine. Branching of the side chain structure proved detrimental to the activity against the CQR strain. PMID:19703776

Condom makers jockey for position in barrier warfare.

PubMed

1995-01-01

U.S. condom manufacturers are receiving competition from high quality Japanese products. However, the sale of a plastic polyurethane condom by U.S. manufacturer, London International, could potentially outsell Japanese ultra-thin condoms. The polyurethane products can be made at a uniform thinness, resulting in a more sensitive condom. Industry analysts are not sure about the impact of a plastic condom. Some feel that even if they prove to be safer than latex condoms, polyurethane condoms will have a difficult time competing against established brands. Others feel that if consumer response is positive, the potential profits provide a strong incentive for companies to invest in the efficacy studies and marketing of a polyurethane product.

Evidence for the timing of sea-level events during MIS 3

NASA Astrophysics Data System (ADS)

Siddall, M.

2005-12-01

Four large sea-level peaks of millennial-scale duration occur during MIS 3. In addition smaller peaks may exist close to the sensitivity of existing methods to derive sea level during these periods. Millennial-scale changes in temperature during MIS 3 are well documented across much of the planet and are linked in some unknown, yet fundamental way to changes in ice volume / sea level. It is therefore highly likely that the timing of the sea level events during MIS 3 will prove to be a `Rosetta Stone' for understanding millennial scale climate variability. I will review observational and mechanistic arguments for the variation of sea level on Antarctic, Greenland and absolute time scales.

Local reconstruction in computed tomography of diffraction enhanced imaging

NASA Astrophysics Data System (ADS)

Huang, Zhi-Feng; Zhang, Li; Kang, Ke-Jun; Chen, Zhi-Qiang; Zhu, Pei-Ping; Yuan, Qing-Xi; Huang, Wan-Xia

2007-07-01

Computed tomography of diffraction enhanced imaging (DEI-CT) based on synchrotron radiation source has extremely high sensitivity of weakly absorbing low-Z samples in medical and biological fields. The authors propose a modified backprojection filtration(BPF)-type algorithm based on PI-line segments to reconstruct region of interest from truncated refraction-angle projection data in DEI-CT. The distribution of refractive index decrement in the sample can be directly estimated from its reconstruction images, which has been proved by experiments at the Beijing Synchrotron Radiation Facility. The algorithm paves the way for local reconstruction of large-size samples by the use of DEI-CT with small field of view based on synchrotron radiation source.

Fluorescence detection of trace TNT by novel cross-linking electropolymerized films both in vapor and aqueous medium.

PubMed

Nie, Heran; Lv, Ying; Yao, Liang; Pan, Yuyu; Zhao, Yang; Li, Peng; Sun, Guannan; Ma, Yuguang; Zhang, Ming

2014-01-15

Electropolymerized (EP) films with high fluorescent efficiency are introduced to the detection of trace 2,4,6-trinitrotoluene (TNT). Three electroactive materials TCPC, OCPC and OCz have been synthesized and their EP films have been demonstrated to be sensitive to TNT. Among them, the TCPC EP films have displayed the highest sensitivity to TNT in both vapor and aqueous medium, even in the natural water. It is proposed that the good performances would be caused by the following two factors: first, the cross-linking network of EP films can generate the cavities which benefit the TNT penetration, and remarkably increase the contact area between the EP films and TNT; second, the frontier orbits distribution leads the fast photo-induced electron transfer (PET) from the TCPC EP films to TNT. Our results prove that these EP films are promising TNT sensing candidates and provide a new method to prepare fluorescent porous films. Copyright © 2013 Elsevier B.V. All rights reserved.

Grating-assisted demodulation of interferometric optical sensors.

PubMed

Yu, Bing; Wang, Anbo

2003-12-01

Accurate and dynamic control of the operating point of an interferometric optical sensor to produce the highest sensitivity is crucial in the demodulation of interferometric optical sensors to compensate for manufacturing errors and environmental perturbations. A grating-assisted operating-point tuning system has been designed that uses a diffraction grating and feedback control, functions as a tunable-bandpass optical filter, and can be used as an effective demodulation subsystem in sensor systems based on optical interferometers that use broadband light sources. This demodulation method has no signal-detection bandwidth limit, a high tuning speed, a large tunable range, increased interference fringe contrast, and the potential for absolute optical-path-difference measurement. The achieved 40-nm tuning range, which is limited by the available source spectrum width, 400-nm/s tuning speed, and a step resolution of 0.4 nm, is sufficient for most practical measurements. A significant improvement in signal-to-noise ratio in a fiber Fabry-Perot acoustic-wave sensor system proved that the expected fringe contrast and sensitivity increase.

A palm-sized high-sensitivity near-infrared fluorescence imager for laparotomy surgery.

PubMed

Dorval, Paul; Mangeret, Norman; Guillermet, Stephanie; Atallah, Ihab; Righini, Christian; Barabino, Gabriele; Coll, Jean-Luc; Rizo, Philippe; Poulet, Patrick

2016-01-01

In laparotomy surgery guided by near-infrared fluorescence imaging, the access to the field of operation is limited by the illumination and/or the imaging field. The side of cavities or organs such as the liver or the heart cannot be examined with the systems available on the market, which are too large and too heavy. In this article, we describe and evaluate a palm sized probe, whose properties, weight, size and sensitivity are adapted for guiding laparotomy surgery. Different experiments have been performed to determine its main characteristics, both on the illumination and imaging sides. The device has been tested for fluorescent molecular probe imaging in preclinical procedures, to prove its ability to be used in cancer nodule detection during surgery. This system is now CE certified for clinical procedures and Indocyanine Green imaging has been performed during clinical investigations: lymphedema and surgical resection of liver metastases of colorectal cancers. Copyright © 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

Effect of Germanium on the TiO2 Photoanode for Dye Sensitized Solar Cell Applications. A Potential Sintering Aid

NASA Astrophysics Data System (ADS)

Ahmad, M. S.; Pandey, AK; Rahim, N. A.

2018-05-01

Anatase titanium-germanium (TiO2-Ge) nanocomposite has been prepared by using colloidal suspension process and investigated for photoanode to be used in dye sensitized solar cell. Ge possesses lower band gap energy compared to TiO2 and has the capability to absorb infrared region of solar spectrum. Its remarkable absorption and good electron transfer ability due to lower band gap energy makes it a potential candidate material in the field of DSSCs to counter important disadvantages such as high probability of electron recombination reactions and absorption of small region (UV region) of solar spectrum. Another advantage is its low sintering temperature which proved to be an added advantage to increase inter-particle contact which in turn leads to improved electron transfer. Scanning electron microscopy (SEM), uv-vis spectroscopy and electron impedance spectroscopy (EIS) have been employed to evaluate the effect of Ge on TiO2photoanode.

Nanobioimaging and sensing of infectious diseases.

PubMed

Tallury, Padmavathy; Malhotra, Astha; Byrne, Logan M; Santra, Swadeshmukul

2010-03-18

New methods to identify trace amount of infectious pathogens rapidly, accurately and with high sensitivity are in constant demand to prevent epidemics and loss of lives. Early detection of these pathogens to prevent, treat and contain the spread of infections is crucial. Therefore, there is a need and urgency for sensitive, specific, accurate, easy-to-use diagnostic tests. Versatile biofunctionalized engineered nanomaterials are proving to be promising in meeting these needs in diagnosing the pathogens in food, blood and clinical samples. The unique optical and magnetic properties of the nanoscale materials have been put to use for the diagnostics. In this review, we focus on the developments of the fluorescent nanoparticles, metallic nanostructures and superparamagnetic nanoparticles for bioimaging and detection of infectious microorganisms. The various nanodiagnostic assays developed to image, detect and capture infectious virus and bacteria in solutions, food or biological samples in vitro and in vivo are presented and their relevance to developing countries is discussed. Copyright 2009 Elsevier B.V. All rights reserved.

Evaluation of NGS and RT-PCR Methods for ALK Rearrangement in European NSCLC Patients: Results from the European Thoracic Oncology Platform Lungscape Project.

PubMed

Letovanec, Igor; Finn, Stephen; Zygoura, Panagiota; Smyth, Paul; Soltermann, Alex; Bubendorf, Lukas; Speel, Ernst-Jan; Marchetti, Antonio; Nonaka, Daisuke; Monkhorst, Kim; Hager, Henrik; Martorell, Miguel; Sejda, Aleksandra; Cheney, Richard; Hernandez-Losa, Javier; Verbeken, Eric; Weder, Walter; Savic, Spasenija; Di Lorito, Alessia; Navarro, Atilio; Felip, Enriqueta; Warth, Arne; Baas, Paul; Meldgaard, Peter; Blackhall, Fiona; Dingemans, Anne-Marie; Dienemann, Hendrik; Dziadziuszko, Rafal; Vansteenkiste, Johan; O'Brien, Cathal; Geiger, Thomas; Sherlock, Jon; Schageman, Jeoffrey; Dafni, Urania; Kammler, Roswitha; Kerr, Keith; Thunnissen, Erik; Stahel, Rolf; Peters, Solange

2018-03-01

The reported prevalence of ALK receptor tyrosine kinase gene (ALK) rearrangement in NSCLC ranges from 2% to 7%. The primary standard diagnostic method is fluorescence in situ hybridization (FISH). Recently, immunohistochemistry (IHC) has also proved to be a reproducible and sensitive technique. Reverse-transcriptase polymerase chain reaction (RT-PCR) has also been advocated, and most recently, the advent of targeted next-generation sequencing (NGS) for ALK and other fusions has become possible. This study compares anaplastic lymphoma kinase (ALK) evaluation with all four techniques in resected NSCLC from the large European Thoracic Oncology Platform Lungscape cohort. A total of 96 cases from the European Thoracic Oncology Platform Lungscape iBiobank, with any ALK immunoreactivity were examined by FISH, central RT-PCR, and NGS. An H-score higher than 120 defines IHC positivity. RNA was extracted from the same formalin-fixed, paraffin-embedded tissues. For RT-PCR, primers covered the most frequent ALK translocations. For NGS, the Oncomine Solid Tumour Fusion Transcript Kit (Thermo Fisher Scientific, Waltham, MA) was used. The concordance was assessed using the Cohen κ coefficient (two-sided α ≤ 5%). NGS provided results for 77 of the 95 cases tested (81.1%), whereas RT-PCR provided results for 77 of 96 (80.2%). Concordance occurred in 55 cases of the 60 cases tested with all four methods (43 ALK negative and 12 ALK positive). Using ALK copositivity for IHC and FISH as the criterion standard, we derived a sensitivity for RT-PCR/NGS of 70.0%/85.0%, with a specificity of 87.1%/79.0%. When either RT-PCR or NGS was combined with IHC, the sensitivity remained the same, whereas the specificity increased to 88.7% and 83.9% respectively. NGS evaluation with the Oncomine Solid Tumour Fusion transcript kit and RT-PCR proved to have high sensitivity and specificity, advocating their use in routine practice. For maximal sensitivity and specificity, ALK status should be assessed by using two techniques and a third one in discordant cases. We therefore propose a customizable testing algorithm. These findings significantly influence existing testing paradigms and have clear clinical and economic impact. Copyright © 2017 International Association for the Study of Lung Cancer. Published by Elsevier Inc. All rights reserved.

System performance and modeling of a bioaerosol detection lidar sensor utilizing polarization diversity

NASA Astrophysics Data System (ADS)

Glennon, John J.; Nichols, Terry; Gatt, Phillip; Baynard, Tahllee; Marquardt, John H.; Vanderbeek, Richard G.

2009-05-01

The weaponization and dissemination of biological warfare agents (BWA) constitute a high threat to civilians and military personnel. An aerosol release, disseminated from a single point, can directly affect large areas and many people in a short time. Because of this threat real-time standoff detection of BWAs is a key requirement for national and military security. BWAs are a general class of material that can refer to spores, bacteria, toxins, or viruses. These bioaerosols have a tremendous size, shape, and chemical diversity that, at present, are not well characterized [1]. Lockheed Martin Coherent Technologies (LMCT) has developed a standoff lidar sensor with high sensitivity and robust discrimination capabilities with a size and ruggedness that is appropriate for military use. This technology utilizes multiwavelength backscatter polarization diversity to discriminate between biological threats and naturally occurring interferents such as dust, smoke, and pollen. The optical design and hardware selection of the system has been driven by performance modeling leading to an understanding of measured system sensitivity. Here we briefly discuss the challenges of standoff bioaerosol discrimination and the approach used by LMCT to overcome these challenges. We review the radiometric calculations involved in modeling direct-detection of a distributed aerosol target and methods for accurately estimating wavelength dependent plume backscatter coefficients. Key model parameters and their validation are discussed and outlined. Metrics for sensor sensitivity are defined, modeled, and compared directly to data taken at Dugway Proving Ground, UT in 2008. Sensor sensitivity is modeled to predict performance changes between day and night operation and in various challenging environmental conditions.

Basophil activation test discriminates between allergy and tolerance in peanut-sensitized children.

PubMed

Santos, Alexandra F; Douiri, Abdel; Bécares, Natalia; Wu, Shih-Ying; Stephens, Alick; Radulovic, Suzana; Chan, Susan M H; Fox, Adam T; Du Toit, George; Turcanu, Victor; Lack, Gideon

2014-09-01

Most of the peanut-sensitized children do not have clinical peanut allergy. In equivocal cases, oral food challenges (OFCs) are required. However, OFCs are laborious and not without risk; thus, a test that could accurately diagnose peanut allergy and reduce the need for OFCs is desirable. To assess the performance of basophil activation test (BAT) as a diagnostic marker for peanut allergy. Peanut-allergic (n = 43), peanut-sensitized but tolerant (n = 36) and non-peanut-sensitized nonallergic (n = 25) children underwent skin prick test (SPT) and specific IgE (sIgE) to peanut and its components. BAT was performed using flow cytometry, and its diagnostic performance was evaluated in relation to allergy versus tolerance to peanut and validated in an independent population (n = 65). BAT in peanut-allergic children showed a peanut dose-dependent upregulation of CD63 and CD203c while there was no significant response to peanut in peanut-sensitized but tolerant (P < .001) and non-peanut-sensitized nonallergic children (P < .001). BAT optimal diagnostic cutoffs showed 97% accuracy, 95% positive predictive value, and 98% negative predictive value. BAT allowed reducing the number of required OFCs by two-thirds. BAT proved particularly useful in cases in which specialists could not accurately diagnose peanut allergy with SPT and sIgE to peanut and to Arah2. Using a 2-step diagnostic approach in which BAT was performed only after equivocal SPT or Arah2-sIgE, BAT had a major effect (97% reduction) on the number of OFCs required. BAT proved to be superior to other diagnostic tests in discriminating between peanut allergy and tolerance, particularly in difficult cases, and reduced the need for OFCs. Copyright © 2014. Published by Elsevier Inc.

Substrate-dependent temperature sensitivity of soil organic matter decomposition

NASA Astrophysics Data System (ADS)

Myachina, Olga; Blagodatskaya, Evgenia

2015-04-01

Activity of extracellular enzymes responsible for decomposition of organics is substrate dependent. Quantity of the substrate is the main limiting factor for enzymatic or microbial heterotrophic activity in soils. Different mechanisms of enzymes response to temperature suggested for low and high substrate availability were never proved for real soil conditions. We compared the temperature responses of enzymes-catalyzed reactions in soils. Basing on Michaelis-Menten kinetics we determined the enzymes affinity to substrate (Km) and mineralization potential of heterotrophic microorganisms (Vmax) 1) for three hydrolytic enzymes: β-1,4-glucosidase, N-acetyl- β -D-glucosaminidase and phosphatase by the application of fluorogenically labeled substrates and 2) for mineralization of 14C-labeled glucose by substrate-dependent respiratory response. Here we show that the amount of available substrate is responsible for temperature sensitivity of hydrolysis of polymers in soil, whereas monomers oxidation to CO2 does not depend on substrate amount and is mainly temperature governed. We also found that substrate affinity of enzymes (which is usually decreases with the temperature) differently responded to warming for the process of depolymerisation versus monomers oxidation. We suggest the mechanism to temperature acclimation based on different temperature sensitivity of enzymes kinetics for hydrolysis of polymers and for monomers oxidation.

Comparative proteomic analysis using samples obtained with laser microdissection and saturation dye labelling.

PubMed

Wilson, Kate E; Marouga, Rita; Prime, John E; Pashby, D Paul; Orange, Paul R; Crosier, Steven; Keith, Alexander B; Lathe, Richard; Mullins, John; Estibeiro, Peter; Bergling, Helene; Hawkins, Edward; Morris, Christopher M

2005-10-01

Comparative proteomic methods are rapidly being applied to many different biological systems including complex tissues. One pitfall of these methods is that in some cases, such as oncology and neuroscience, tissue complexity requires isolation of specific cell types and sample is limited. Laser microdissection (LMD) is commonly used for obtaining such samples for proteomic studies. We have combined LMD with sensitive thiol-reactive saturation dye labelling of protein samples and 2-D DIGE to identify protein changes in a test system, the isolated CA1 pyramidal neurone layer of a transgenic (Tg) rat carrying a human amyloid precursor protein transgene. Saturation dye labelling proved to be extremely sensitive with a spot map of over 5,000 proteins being readily produced from 5 mug total protein, with over 100 proteins being significantly altered at p < 0.0005. Of the proteins identified, all showed coherent changes associated with transgene expression. It was, however, difficult to identify significantly different proteins using PMF and MALDI-TOF on gels containing less than 500 mug total protein. The use of saturation dye labelling of limiting samples will therefore require the use of highly sensitive MS techniques to identify the significantly altered proteins isolated using methods such as LMD.

Fluorescent high-performance liquid chromatographic analysis of vigabatrin enantiomers after derivatizing with naproxen acyl chloride.

PubMed

Hsieh, Chun-Yu; Wang, Shing-Yaw; Kwan, Aij-Lie; Wu, Hsin-Lung

2008-01-18

Vigabatrin is widely used as an anticonvulsant in the treatment of seizures. Vigabatrin is usually supplied as racemate in formulation, but only the (S)-(+)-enantiomer of vigabatrin is pharmacologically active. A simple and sensitive liquid chromatographic method is described for the separation and quantification of vigabatrin enantiomers. The method is based on derivatizing racemic vigabatrin with a fluorescent chiral reagent (naproxen acyl chloride). The resulting diastereomeric derivatives are highly responsive to a fluorimetric detector (lambda(ex)=230 nm, lambda(em)=350 nm). The lower quantitation limit of the method is attainable at 25 nM for (S)-(+)-vigabatrin or (R)-(-)-vigabatrin with a detection limit of about 2.5 nM (S/N=3 with 10 microl injected). Application of the method to the analysis of vigabatrin in serum of dosed patients proved feasible.

High-performance liquid chromatography coupled with post-column dual-bioactivity assay for simultaneous screening of xanthine oxidase inhibitors and free radical scavengers from complex mixture.

PubMed

Li, D Q; Zhao, J; Li, S P

2014-06-06

Xanthine oxidase (XO) can catalyze hypoxanthine and xanthine to generate uric acid and reactive oxygen species (ROS), including superoxide anion radical (O₂(•-)) and hydrogen peroxide. XO inhibitors and free radical scavengers are beneficial to the treatment of gout and many related diseases. In the present study, an on-line high-performance liquid chromatography (HPLC) coupled with post-column dual-bioactivity assay was established and successfully applied to simultaneously screening of XO inhibitors and free radical scavengers from a complex mixture, Oroxylum indicum extract. The integrated system of HPLC separation, bioactivity screening and mass spectrometry identification was proved to be simple and effective for rapid and sensitive screening of individual bioactive compounds in complex mixtures. Copyright © 2014 Elsevier B.V. All rights reserved.

Background radiation measurements at high power research reactors

DOE PAGES

Ashenfelter, J.; Yeh, M.; Balantekin, B.; ...

2015-10-23

Research reactors host a wide range of activities that make use of the intense neutron fluxes generated at these facilities. Recent interest in performing measurements with relatively low event rates, e.g. reactor antineutrino detection, at these facilities necessitates a detailed understanding of background radiation fields. Both reactor-correlated and naturally occurring background sources are potentially important, even at levels well below those of importance for typical activities. Here we describe a comprehensive series of background assessments at three high-power research reactors, including γ-ray, neutron, and muon measurements. For each facility we describe the characteristics and identify the sources of the backgroundmore » fields encountered. Furthermore, the general understanding gained of background production mechanisms and their relationship to facility features will prove valuable for the planning of any sensitive measurement conducted therein.« less

Weldability of high-toughness iron - 12 percent-nickel alloys with reactive metal additions of titanium, aluminum, or niobium

NASA Technical Reports Server (NTRS)

Delvetian, J. H.; Stephens, J. R.; Witzke, W. R.

1977-01-01

Three exceptionally high toughness Fe-12Ni alloys designed for cryogenic service were welded by using the gas tungsten arc welding process. Evaluation of their weldability included equivalent energy fracture toughness tests, transverse weld tensile tests at -196 and 25 C, and weld crack sensitivity tests. The Fe-12Ni-0.25Ti alloy proved extremely weldable for cryogenic applications, having weld and heat affected zone properties comparable to those of the wrought base alloy. The Fe-12Ni-0.5Al alloy had good weld properties only after the weld joint was heat treated. The Fe-12Ni-0.25Nb alloy was not considered weldable for cryogenic use because of its poor weld joint properties at -196 C and its susceptibility to hot cracking.

Recent Advances in Bioprinting and Applications for Biosensing

PubMed Central

Dias, Andrew D.; Kingsley, David M.; Corr, David T.

2014-01-01

Future biosensing applications will require high performance, including real-time monitoring of physiological events, incorporation of biosensors into feedback-based devices, detection of toxins, and advanced diagnostics. Such functionality will necessitate biosensors with increased sensitivity, specificity, and throughput, as well as the ability to simultaneously detect multiple analytes. While these demands have yet to be fully realized, recent advances in biofabrication may allow sensors to achieve the high spatial sensitivity required, and bring us closer to achieving devices with these capabilities. To this end, we review recent advances in biofabrication techniques that may enable cutting-edge biosensors. In particular, we focus on bioprinting techniques (e.g., microcontact printing, inkjet printing, and laser direct-write) that may prove pivotal to biosensor fabrication and scaling. Recent biosensors have employed these fabrication techniques with success, and further development may enable higher performance, including multiplexing multiple analytes or cell types within a single biosensor. We also review recent advances in 3D bioprinting, and explore their potential to create biosensors with live cells encapsulated in 3D microenvironments. Such advances in biofabrication will expand biosensor utility and availability, with impact realized in many interdisciplinary fields, as well as in the clinic. PMID:25587413

Highly selective and sensitive coumarin-triazole-based fluorometric 'turn-off' sensor for detection of Pb2+ ions.

PubMed

Shaily; Kumar, Ajay; Parveen, Iram; Ahmed, Naseem

2018-06-01

Exposure to even very low concentrations of Pb 2+ is known to cause cardiovascular, neurological, developmental, and reproductive disorders, and affects children in particular more severely. Consequently, much effort has been dedicated to the development of colorimetric and fluorescent sensors that can selectively detect Pb 2+ ions. Here, we describe the development of a triazole-based fluorescent sensor L5 for Pb 2+ ion detection. The fluorescence intensity of chemosensor L5 was selectively quenched by Pb 2+ ions and a clear color change from colorless to yellow could be observed by the naked eye. Chemosensor L5 exhibited high sensitivity and selectivity towards Pb 2+ ions in phosphate-buffered solution [20 mM, 1:9 DMSO/H 2 O (v/v), pH 8.0] with a 1:1 binding stoichiometry, a detection limit of 1.9 nM and a 6.76 × 10 6  M -1 binding constant. Additionally, low-cost and easy-to-prepare test strips impregnated with chemosensor L5 were also produced for efficient of Pb 2+ detection and proved the practical use of this test. Copyright © 2018 John Wiley & Sons, Ltd.

Non-invasive assessment of parasitic nematode species diversity in wild Soay sheep using molecular markers.

PubMed

Wimmer, B; Craig, B H; Pilkington, J G; Pemberton, J M

2004-04-01

Considerable effort has been put into detecting and identifying parasitic nematodes in live ruminants, but to date most studies are limited to a small group of nematodes and/or to experimentally infected sheep. In this study, a PCR-based assay using species-specific primer pairs, located in the second internal transcribed spacer ribosomal DNA, was developed to identify nine different species from six different families of parasitic nematodes in a wild, unmanaged and naturally infected population of sheep. Each primer pair was tested for its specificity and sensitivity and it exclusively amplified the species it was designed for and exhibited a high degree of sensitivity. The method was applied to eggs and cultured larvae to identify the parasitic nematodes present in a pooled faecal sample from several host individuals with unknown parasite burden. To test detection reliability, a faecal sample from an individual with known parasite burden (through post-mortem analysis) was also examined. All species present could be correctly identified by PCR, but detecting very low levels and/or early stages of infection proved to be difficult. The method was also tested for its applicability to high through-put screening of faecal samples.

Microfluidic Diatomite Analytical Devices for Illicit Drug Sensing with ppb-Level Sensitivity.

PubMed

Kong, Xianming; Chong, Xinyuan; Squire, Kenny; Wang, Alan X

2018-04-15

The escalating research interests in porous media microfluidics, such as microfluidic paper-based analytical devices, have fostered a new spectrum of biomedical devices for point-of-care (POC) diagnosis and biosensing. In this paper, we report microfluidic diatomite analytical devices (μDADs), which consist of highly porous photonic crystal biosilica channels, as an innovative lab-on-a-chip platform to detect illicit drugs. The μDADs in this work are fabricated by spin-coating and tape-stripping diatomaceous earth on regular glass slides with cross section of 400×30µm 2 . As the most unique feature, our μDADs can simultaneously perform on-chip chromatography to separate small molecules from complex biofluidic samples and acquire the surface-enhanced Raman scattering spectra of the target chemicals with high specificity. Owing to the ultra-small dimension of the diatomite microfluidic channels and the photonic crystal effect from the fossilized diatom frustules, we demonstrate unprecedented sensitivity down to part-per-billion (ppb) level when detecting pyrene (1ppb) from mixed sample with Raman dye and cocaine (10 ppb) from human plasma. This pioneering work proves the exclusive advantage of μDADs as emerging microfluidic devices for chemical and biomedical sensing, especially for POC drug screening.

Sensitivity of Offshore Surface Fluxes and Sea Breezes to the Spatial Distribution of Sea-Surface Temperature

NASA Astrophysics Data System (ADS)

Lombardo, Kelly; Sinsky, Eric; Edson, James; Whitney, Michael M.; Jia, Yan

2018-03-01

A series of numerical sensitivity experiments is performed to quantify the impact of sea-surface temperature (SST) distribution on offshore surface fluxes and simulated sea-breeze dynamics. The SST simulations of two mid-latitude sea-breeze events over coastal New England are performed using a spatially-uniform SST, as well as spatially-varying SST datasets of 32- and 1-km horizontal resolutions. Offshore surface heat and buoyancy fluxes vary in response to the SST distribution. Local sea-breeze circulations are relatively insensitive, with minimal differences in vertical structure and propagation speed among the experiments. The largest thermal perturbations are confined to the lowest 10% of the sea-breeze column due to the relatively high stability of the mid-Atlantic marine atmospheric boundary layer (ABL) suppressing vertical mixing, resulting in the depth of the marine layer remaining unchanged. Minimal impacts on the column-averaged virtual potential temperature and sea-breeze depth translates to small changes in sea-breeze propagation speed. This indicates that the use of datasets with a fine-scale SST may not produce more accurate sea-breeze simulations in highly stable marine ABL regimes, though may prove more beneficial in less stable sub-tropical environments.

High efficiency and stability of quasi-solid-state dye-sensitized ZnO solar cells using graphene incorporated soluble polystyrene gel electrolytes

NASA Astrophysics Data System (ADS)

Bi, Shi-Qing; Meng, Fan-Li; Zheng, Yan-Zhen; Han, Xue; Tao, Xia; Chen, Jian-Feng

2014-12-01

We report on the preparation of highly effective composite electrolytes by combining the two-dimensional graphene (Gra) and soluble polystyrene (PS) nanobeads on Pt counter electrode for the quasi-solid-state electrolytes of ZnO based dye-sensitized solar cells (DSCs). Under an optimized Gra/electrolyte ratio of 12 mg mL-1, the ionic conductivity (σ) of Gra-PS electrolyte was significantly improved from 32.8 mS cm-1 to 39.8 mS cm-1. And the electrochemical impedance spectroscopy (EIS) analysis proved that the ZnO-DSC with the optimized composite electrolyte possessed the lowest impedance value. As a result, the overall power conversion efficiencies (PCEs) of quasi-solid-state ZnO-DSCs significantly enhanced to 5.08% from initial 4.09%. Moreover, the results of long-term stability assays showed that the gel-state Gra-PS ZnO-DSC could retain over 90% of its initial PCE after radiation of 1000 h under full sunlight outdoors. It is anticipated that this work may provide an effective way to increase the cell efficiency by the introduction of Gra into gel electrolyte as well as a great potential for practical application.

Adenosine-derived doped carbon dots: From an insight into effect of N/P co-doping on emission to highly sensitive picric acid sensing.

PubMed

Li, Na; Liu, Shi Gang; Fan, Yu Zhu; Ju, Yan Jun; Xiao, Na; Luo, Hong Qun; Li, Nian Bing

2018-07-12

The various synthetic routes of carbon dots (C-dots) feature a considerable step toward their potential use in chemical sensors and biotechnology. Herein, by coupling phosphorus and nitrogen element introduction, the adenosine-derived N/P co-doped C-dots with fluorescence enhancement were achieved. By separately employing adenosine, adenosine monophosphate, adenosine diphosphate, and adenosine-5'-triphosphate as precursors, the effect of N/P co-doping on the fluorescence emission is discussed in detail. The formed C-dots with adenosine monophosphate exhibited strong blue fluorescence with a high quantum yield of 33.81%. Then the C-dots were employed as a fluorescent probe and utilized to develop a fast, sensitive, and selective picric acid sensor. The fluorescence of C-dots can be quenched by picric acid immediately, giving rise to a picric acid determination down to 30 nM. The possible mechanism of fluorescence quenching was discussed, which was proved to be inner filter effect and static quenching. Moreover, this method has the potential to detect picric acid in environmental water samples. Copyright © 2018 Elsevier B.V. All rights reserved.

Plasma Concentration of the Neurofilament Light Protein (NFL) is a Biomarker of CNS Injury in HIV Infection: A Cross-Sectional Study.

PubMed

Gisslén, Magnus; Price, Richard W; Andreasson, Ulf; Norgren, Niklas; Nilsson, Staffan; Hagberg, Lars; Fuchs, Dietmar; Spudich, Serena; Blennow, Kaj; Zetterberg, Henrik

2016-01-01

Cerebrospinal fluid (CSF) neurofilament light chain protein (NFL) is a sensitive marker of neuronal injury in a variety of neurodegenerative conditions, including the CNS dysfunction injury that is common in untreated HIV infection. However, an important limitation is the requirement for lumbar puncture. For this reason, a sensitive and reliable blood biomarker of CNS injury would represent a welcome advance in both clinical and research settings. To explore whether plasma concentrations of NFL might be used to detect CNS injury in HIV infection, an ultrasensitive Single molecule array (Simoa) immunoassay was developed. Using a cross-sectional design, we measured NFL in paired CSF and plasma samples from 121 HIV-infected subjects divided into groups according to stage of their systemic disease, presence of overt HIV-associated dementia (HAD), and after antiretroviral treatment (ART)-induced viral suppression. HIV-negative controls were also examined. Plasma and CSF NFL concentrations were very highly correlated (r = 0.89, P < 0.0001). While NFL was more than 50-fold lower plasma than CSF it was within the quantifiable range of the new plasma assay in all subjects, including the HIV negatives and the HIV positives with normal CSF NFL concentrations. The pattern of NFL changes were almost identical in plasma and CSF, both exhibiting similar age-related increases in concentrations along with highest values in HAD and substantial elevations in ART-naïve neuroasymptomatic subjects with low blood CD4(+) T cells. These results show that plasma NFL may prove a valuable tool to evaluate ongoing CNS injury in HIV infection that may be applied in the clinic and in research settings to assess the presence if active CNS injury. Because CSF NFL is also elevated in a variety of other CNS disorders, sensitive measures of plasma NFL may similarly prove useful in other settings.

Plasma Concentration of the Neurofilament Light Protein (NFL) is a Biomarker of CNS Injury in HIV Infection: A Cross-Sectional Study

PubMed Central

Gisslén, Magnus; Price, Richard W.; Andreasson, Ulf; Norgren, Niklas; Nilsson, Staffan; Hagberg, Lars; Fuchs, Dietmar; Spudich, Serena; Blennow, Kaj; Zetterberg, Henrik

2015-01-01

Background Cerebrospinal fluid (CSF) neurofilament light chain protein (NFL) is a sensitive marker of neuronal injury in a variety of neurodegenerative conditions, including the CNS dysfunction injury that is common in untreated HIV infection. However, an important limitation is the requirement for lumbar puncture. For this reason, a sensitive and reliable blood biomarker of CNS injury would represent a welcome advance in both clinical and research settings. Methods To explore whether plasma concentrations of NFL might be used to detect CNS injury in HIV infection, an ultrasensitive Single molecule array (Simoa) immunoassay was developed. Using a cross-sectional design, we measured NFL in paired CSF and plasma samples from 121 HIV-infected subjects divided into groups according to stage of their systemic disease, presence of overt HIV-associated dementia (HAD), and after antiretroviral treatment (ART)-induced viral suppression. HIV-negative controls were also examined. Findings Plasma and CSF NFL concentrations were very highly correlated (r = 0.89, P < 0.0001). While NFL was more than 50-fold lower plasma than CSF it was within the quantifiable range of the new plasma assay in all subjects, including the HIV negatives and the HIV positives with normal CSF NFL concentrations. The pattern of NFL changes were almost identical in plasma and CSF, both exhibiting similar age-related increases in concentrations along with highest values in HAD and substantial elevations in ART-naïve neuroasymptomatic subjects with low blood CD4+ T cells. Interpretation These results show that plasma NFL may prove a valuable tool to evaluate ongoing CNS injury in HIV infection that may be applied in the clinic and in research settings to assess the presence if active CNS injury. Because CSF NFL is also elevated in a variety of other CNS disorders, sensitive measures of plasma NFL may similarly prove useful in other settings. PMID:26870824

Poor horse traders: large mammals trade survival for reproduction during the process of feralization

PubMed Central

Grange, Sophie; Duncan, Patrick; Gaillard, Jean-Michel

2009-01-01

We investigated density dependence on the demographic parameters of a population of Camargue horses (Equus caballus), individually monitored and unmanaged for eight years. We also analysed the contributions of individual demographic parameters to changes in the population growth rates. The decrease in resources caused a loss of body condition. Adult male survival was not affected, but the survival of foals and adult females decreased with increasing density. Prime-aged females maintained high reproductive performance at high density, and their survival decreased. The higher survival of adult males compared with females at high density presumably results from higher investment in reproduction by mares. The high fecundity in prime-aged females, even when at high density, may result from artificial selection for high reproductive performance, which is known to have occurred in all the major domestic ungulates. Other studies suggest that feral ungulates including cattle and sheep, as these horses, respond differently from wild ungulates to increases in density, by trading adult survival for reproduction. As a consequence, populations of feral animals should oscillate more strongly than their wild counterparts, since they should be both more invasive (as they breed faster), and more sensitive to harsh environmental conditions (as the population growth rate of long-lived species is consistently more sensitive to a given proportional change in adult survival than to the same change in any other vital rate). If this principle proves to be general, it has important implications for management of populations of feral ungulates. PMID:19324787

Generation and characterization of a human-mouse chimeric high-affinity antibody that detects the DYKDDDDK FLAG peptide.

PubMed

Ikeda, Koki; Koga, Tomoaki; Sasaki, Fumiyuki; Ueno, Ayumi; Saeki, Kazuko; Okuno, Toshiaki; Yokomizo, Takehiko

2017-05-13

DYKDDDDK peptide (FLAG) is a useful tool for investigating the function and localization of proteins whose antibodies (Abs) are not available. We recently established a high-affinity monoclonal antibody (mAb) for FLAG (clone 2H8). The 2H8 Ab is highly sensitive for detecting FLAG-tagged proteins by flowcytometry and immunoprecipitation, but it can yield nonspecific signals in immunohistochemistry of mouse tissues because it is of mouse origin. In this study, we reduced nonspecific signals by generating a chimeric 2H8 Ab with Fc fragments derived from human immunoglobulin. We fused a 5' terminal cDNA fragments for the Fab region of 2H8 mAb with 3' terminal cDNA fragments for Fc region of human IgG1. We transfected both chimeric plasmids and purified the resulting human-mouse chimeric 2H8. The chimeric 2H8 Ab successfully detected FLAG-tagged proteins in flowcytometry with anti-human IgG secondary Ab with comparable sensitivity to 2H8 mAb. Importantly, chimeric 2H8 detected specific FLAG peptide signals without nonspecific signals in immunohistochemical analysis with mouse tissues. This human-mouse chimeric high-affinity anti-FLAG Ab will prove useful for future immunohistochemical analysis of mouse tissues. Copyright © 2017 Elsevier Inc. All rights reserved.

A Fiber Bragg Grating Sensor for Radial Artery Pulse Waveform Measurement.

PubMed

Jia, Dagong; Chao, Jing; Li, Shuai; Zhang, Hongxia; Yan, Yingzhan; Liu, Tiegen; Sun, Ye

2018-04-01

In this paper, we report the design and experimental validation of a novel optical sensor for radial artery pulse measurement based on fiber Bragg grating (FBG) and lever amplification mechanism. Pulse waveform analysis is a diagnostic tool for clinical examination and disease diagnosis. High fidelity radial artery pulse waveform has been investigated in clinical studies for estimating central aortic pressure, which is proved to be predictors of cardiovascular diseases. As a three-dimensional cylinder, the radial artery needs to be examined from different locations to achieve optimal pulse waveform for estimation and diagnosis. The proposed optical sensing system is featured as high sensitivity and immunity to electromagnetic interference for multilocation radial artery pulse waveform measurement. The FBG sensor can achieve the sensitivity of 8.236 nm/N, which is comparable to a commonly used electrical sensor. This FBG-based system can provide high accurate measurement, and the key characteristic parameters can be then extracted from the raw signals for clinical applications. The detecting performance is validated through experiments guided by physicians. In the experimental validation, we applied this sensor to measure the pulse waveforms at various positions and depths of the radial artery in the wrist according to the diagnostic requirements. The results demonstrate the high feasibility of using optical systems for physiological measurement and using this FBG sensor for radial artery pulse waveform in clinical applications.

The Socratic Dialogue and Teacher Education

ERIC Educational Resources Information Center

Knezic, Dubravka; Wubbels, Theo; Elbers, Ed; Hajer, Maaike

2010-01-01

This article argues that the Socratic Dialogue in the Nelson and Heckmann tradition will prove a considerable contribution in training teachers. A review of the literature and empirical research supports the claim that the Socratic Dialogue promotes student teachers' interpersonal sensitivity while stimulating conceptual understanding. The article…

Global boundedness to a chemotaxis system with singular sensitivity and logistic source

NASA Astrophysics Data System (ADS)

Zhao, Xiangdong; Zheng, Sining

2017-02-01

We consider the parabolic-parabolic Keller-Segel system with singular sensitivity and logistic source: u_t=Δ u-χ nabla \\cdot (u/vnabla v) +ru-μ u^2, v_t=Δ v-v+u under the homogeneous Neumann boundary conditions in a smooth bounded domain Ω subset {R}^2, χ ,μ >0 and rin {R}. It is proved that the system exists globally bounded classical solutions if r>χ ^2/4 for 0<χ ≤ 2, or r>χ -1 for χ >2.

Determination of Caffeine in Beverages by Capillary Zone Electrophoresis: An Experiment for the Undergraduate Analytical Laboratory

NASA Astrophysics Data System (ADS)

Conte, Eric D.; Barry, Eugene F.; Rubinstein, Harry

1996-12-01

Certain individuals may be sensitive to specific compounds in comsumer products. It is important to quantify these analytes in food products in order to monitor their intake. Caffeine is one such compound. Determination of caffeine in beverages by spectrophotometric procedures requires an extraction procedure, which can prove time-consuming. Although the corresponding determination by HPLC allows for a direct injection, capillary zone electrophoresis provides several advantages such as extremely low solvent consumption, smaller sample volume requirements, and improved sensitivity.

Sensitive life detection strategies for low-biomass environments: optimizing extraction of nucleic acids adsorbing to terrestrial and Mars analogue minerals.

PubMed

Direito, Susana O L; Marees, Andries; Röling, Wilfred F M

2012-07-01

The adsorption of nucleic acids to mineral matrixes can result in low extraction yields and negatively influences molecular microbial ecology studies, in particular for low-biomass environments on Earth and Mars. We determined the recovery of nucleic acids from a range of minerals relevant to Earth and Mars. Clay minerals, but also other silicates and nonsilicates, showed very low recovery (< 1%). Consequently, optimization of DNA extraction was directed towards clays. The high temperatures and acidic conditions used in some methods to dissolve mineral matrices proved to destruct DNA. The most efficient method comprised a high phosphate solution (P/EtOH; 1 M phosphate, 15% ethanol buffer at pH 8) introduced at the cell-lysing step in DNA extraction, to promote chemical competition with DNA for adsorption sites. This solution increased DNA yield from clay samples spiked with known quantities of cells up to nearly 100-fold. DNA recovery was also enhanced from several mineral samples retrieved from an aquifer, while maintaining reproducible DGGE profiles. DGGE profiles were obtained for a clay sample for which no profile could be generated with the standard DNA isolation protocol. Mineralogy influenced microbial community composition. The method also proved suitable for the recovery of low molecular weight DNA (< 1.5 kb). © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

"Spider"-shaped porphyrins with conjugated pyridyl anchoring groups as efficient sensitizers for dye-sensitized solar cells.

PubMed

Stangel, Christina; Bagaki, Anthi; Angaridis, Panagiotis A; Charalambidis, Georgios; Sharma, Ganesh D; Coutsolelos, Athanasios G

2014-11-17

Two novel "spider-shaped" porphyrins, meso-tetraaryl-substituted 1PV-Por and zinc-metalated 1PV-Zn-Por, bearing four oligo(p-phenylenevinylene) (oPPV) pyridyl groups with long dodecyloxy chains on the phenyl groups, have been synthesized. The presence of four pyridyl groups in both porphyrins, which allow them to act as anchoring groups upon coordination to various Lewis acid sites, the conjugated oPPV bridges, which offer the possibility of electronic communication between the porphyrin core and the pyridyl groups, and the dodecyloxy groups, which offer the advantage of high solubility in a variety of organic solvents of different polarities and could prevent porphyrin aggregation, renders porphyrins 1PV-Por and 1PV-Zn-Por very promising sensitizers for dye-sensitized solar cells (DSSCs). Photophysical measurements, together with electrochemistry experiments and density functional theory calculations, suggest that both porphyrins have frontier molecular orbital energy levels that favor electron injection and dye regeneration in DSSCs. Solar cells sensitized by 1PV-Por and 1PV-Zn-Por were fabricated, and it was found that they show power conversion efficiencies (PCEs) of 3.28 and 5.12%, respectively. Photovoltaic measurements (J-V curves) together with incident photon-to-electron conversion efficiency spectra of the two cells reveal that the higher PCE value of the DSSC based on 1PV-Zn-Por is ascribed to higher short-circuit current (Jsc), open-circuit voltage (Voc), and dye loading values. Emission spectra and electrochemistry experiments suggest a greater driving force for injection of the photogenerated electrons into the TiO2 conduction band for 1PV-Zn-Por rather than its free-base analogue. Furthermore, electrochemical impedance spectroscopy measurements prove that the utilization of 1PV-Zn-Por as a sensitizer offers a high charge recombination resistance and, therefore, leads to a longer electron lifetime.

[Individual responses of arterial pressure to geomagnetic activity in practically healthy subjects].

PubMed

Zenchenko, T A; Dimitrova, S; Stoilova, I; Breus, T K

2009-01-01

Dynamic analysis of arterial blood pressure in relation to the Earth's magnetic field perturbations was performed in 77 practically healthy volunteers (staff of Bulgarian Academy of Sciences). Almost half of them proved magneto-sensitive, i.e. experienced AP elevation with increased geomagnetic activity. The probability of development of magnetic sensitivity was independent of age and gender but increased in volunteers having even mild cardiovascular pathology. These subjects complained of worsened health condition upon a rise in geomagnetic activity. However, some volunteers reported deteriorated well-being without AD elevation. It means that AD measurement may be insufficient for reliable monitoring magnetic sensitivity.

Comparison of non-invasive methods for the assessment of haemodynamic drug effects in healthy male and female volunteers: sex differences in cardiovascular responsiveness.

PubMed Central

Wolzt, M; Schmetterer, L; Rheinberger, A; Salomon, A; Unfried, C; Breiteneder, H; Ehringer, H; Eichler, H G; Fercher, A F

1995-01-01

1. The study was performed to determine the sensitivity and short-term and day-to-day variability of a novel technique based on laser interferometry of ocular fundus pulsations and of non-invasive methods for the quantification of haemodynamic drug effects. An additional aim was to assess sex differences in haemodynamic responsiveness to cardiovascular drugs in male and female healthy volunteers. 2. Ten males and nine females (age range 20-33 years) were studied in a double-blind, randomized, cross-over trial. Simultaneous measurements from systemic haemodynamics, laser interferometry of ocular fundus pulsations, systolic time intervals from mechanocardiography, a/b ratio from oxymetric fingerplethysmography and Doppler sonography of the radial artery were used to describe the haemodynamic effects of cumulative, stepwise increasing intravenous doses of phenylephrine, isoprenaline, sodium nitroprusside and of placebo. 3. Laser interferometry detected the isoprenaline-effects at the lowest dose level of 0.1 micrograms min-1 with a high signal-to-noise ratio. The reproducibility of measurements under baseline was high, no changes were observed after systemically effective doses of phenylephrine or sodium nitroprusside. Systolic time intervals were sensitive and specific for isoprenaline-induced effects, PEP and QS2c-measurements had high reproducibility. Fingerplethysmography proved a sensitive measurement for the detection of the vasodilating effects of sodium nitroprusside, but was not specific, and showed low reproducibility. Measurements from Doppler sonography had lower reproducibility and sensitivity compared with the other applied methods. 4. There was a significant sex difference for several of the haemodynamic parameters under baseline conditions; however, the responsiveness to the drugs under study was not different, when drug effects were expressed as %-change from the baseline. 5. Laser interferometry is a valuable non-invasive, highly sensitive and specific approach for the detection of pulse pressure changes. A battery of non-invasive tests appears useful for the characterization of cardiovascular drugs. Gender differences may not pose a relevant problem for the study of acute haemodynamic effects of cardiovascular drugs. Images Figure 1 PMID:7640140

Transesophageal Echocardiography, 3-Dimensional and Speckle Tracking Together as Sensitive Markers for Early Outcome in Patients With Left Ventricular Dysfunction Undergoing Cardiac Surgery.

PubMed

Kumar, Alok; Puri, Goverdhan Dutt; Bahl, Ajay

2017-10-01

Speckle tracking, when combined with 3-dimensional (3D) left ventricular ejection fraction, might prove to be a more sensitive marker for postoperative ventricular dysfunction. This study investigated early outcomes in a cohort of patients with left ventricular dysfunction undergoing cardiac surgery. Prospective, blinded, observational study. University hospital; single institution. The study comprised 73 adult patients with left ventricular ejection fraction <50% undergoing cardiac surgery using cardiopulmonary bypass. Routine transesophageal echocardiography before and after bypass. Global longitudinal strain using speckle tracking and 3D left ventricular ejection fraction were computed using transesophageal echocardiography. Mean prebypass global longitudinal strain and 3D left ventricle ejection fraction were significantly lower in patients with postoperative low-cardiac-output syndrome compared with patients who did not develop low cardiac output (global longitudinal strain -7.5% v -10.7% and 3D left ventricular ejection fraction 29% v 39%, respectively; p < 0.0001). The cut-off value of global longitudinal strain predicting postoperative low-cardiac-output syndrome was -6%, with 95% sensitivity and 68% specificity; and 3D left ventricular ejection fraction was 19% with 98% sensitivity and 81% specificity. Preoperative left ventricular global longitudinal strain (-6%) and 3D left ventricular ejection fraction (19%) together could act as predictor of postoperative low-cardiac-output states with high sensitivity (99.9%) in patients undergoing cardiac surgery. Copyright © 2017 Elsevier Inc. All rights reserved.

Integration of spectral domain optical coherence tomography with microperimetry generates unique datasets for the simultaneous identification of visual function and retinal structure in ophthalmological applications

NASA Astrophysics Data System (ADS)

Koulen, Peter; Gallimore, Gary; Vincent, Ryan D.; Sabates, Nelson R.; Sabates, Felix N.

2011-06-01

Conventional perimeters are used routinely in various eye disease states to evaluate the central visual field and to quantitatively map sensitivity. However, standard automated perimetry proves difficult for retina and specifically macular disease due to the need for central and steady fixation. Advances in instrumentation have led to microperimetry, which incorporates eye tracking for placement of macular sensitivity values onto an image of the macular fundus thus enabling a precise functional and anatomical mapping of the central visual field. Functional sensitivity of the retina can be compared with the observed structural parameters that are acquired with high-resolution spectral domain optical coherence tomography and by integration of scanning laser ophthalmoscope-driven imaging. Findings of the present study generate a basis for age-matched comparison of sensitivity values in patients with macular pathology. Microperimetry registered with detailed structural data performed before and after intervention treatments provides valuable information about macular function, disease progression and treatment success. This approach also allows for the detection of disease or treatment related changes in retinal sensitivity when visual acuity is not affected and can drive the decision making process in choosing different treatment regimens and guiding visual rehabilitation. This has immediate relevance for applications in central retinal vein occlusion, central serous choroidopathy, age-related macular degeneration, familial macular dystrophy and several other forms of retina related visual disability.

Evaluation of Tizian overlays by means of a swept source optical coherence tomography system

NASA Astrophysics Data System (ADS)

Marcauteanu, Corina; Sinescu, Cosmin; Negrutiu, Meda Lavinia; Stoica, Eniko Tunde; Topala, Florin; Duma, Virgil Florin; Bradu, Adrian; Podoleanu, Adrian Gh.

2016-03-01

The teeth affected by pathologic attrition can be restored by a minimally invasive approach, using Tizian overlays. In this study we prove the advantages of a fast swept source (SS) OCT system in the evaluation of Tizian overlays placed in an environment characterized by high occlusal forces. 12 maxillary first premolars were extracted and prepared for overlays. The Tizian overlays were subjected to 3000 alternating cycles of thermo-cycling (from -10°C to +50°C) and to mechanical occlusal overloads (at 800 N). A fast SS OCT system was used to evaluate the Tizian overlays before and after the mechanical and thermal straining. The SS (Axsun Technologies, Billerica, MA) has a central wavelength of 1060 nm, sweeping range of 106 nm (quoted at 10 dB) and a 100 kHz line rate. The depth resolution of the system, measured experimentally in air was 10 μm. The imaging system used for this study offers high spatial resolutions in both directions, transversal and longitudinal of around 10 μm, a high sensitivity, and it is also able to acquire entire tridimensional (3D)/volume reconstructions as fast as 2.5 s. Once the full dataset was acquired, rendered high resolutions en-face projections could be produced. Using them, the overlay (i.e., cement) abutment tooth interfaces were remarked both on B-scans/two-dimensional (2D) sections and in the 3D reconstructions. Using the system several open interfaces were possible to detect. The fast SS OCT system thus proves useful in the evaluation of zirconia reinforced composite overlays, placed in an environment characterized by high occlusal forces.

Chemiluminescence Resonance Energy Transfer-based Detection for Microchip Electrophoresis

PubMed Central

Huang, Yong; Shi, Ming; Liu, Rongjun

2010-01-01

Since the channels in micro- and nanofluidic devices are extremely small, a sensitive detection is required following microchip electrophoresis (MCE). This work describes a highly sensitive and yet universal detection scheme based on chemiluminescence resonance energy transfer (CRET) for MCE. It was found that an efficient CRET occurred between a luminol donor and a CdTe quantum dot (QD) acceptor in the luminol-NaBrO-QD system, and that it was sensitively suppressed by the presence of certain organic compounds of biological interest including biogenic amines and thiols, amino acids, organic acids, and steroids. These findings allowed developing sensitive MCE-CL assays for the tested compounds. The proposed MCE-CL methods showed desired analytical figures of merit such as a wide concentration range of linear response. Detection limits obtained were ~10−9 M for biogenic amines including dopamine and epinephrine, and ~ 10−8 M for biogenic thiols (e.g. glutathione and acetylcysteine), organic acids (i.e. ascorbic acid and uric acid), estrogens, and native amino acids. These were 10 to 1000 times more sensitive than those of previously reported MCE-based methods with chemiluminescence, electrochemical, or laser induced fluorescence detection for quantifying corresponding compounds. To evaluate the applicability of the present MCE-CL method for analyzing real biological samples, it was used to determine amino acids in individual human red blood cells. Nine amino acids including Lys, Ser, Ala, Glu, Trp, etc. were detected. The contents ranged from 3 to 31 amol /cell. The assay proved to be simple, quick, reproducible, and very sensitive. PMID:20121202

Frequently Asked Questions on Ebola Virus Disease

MedlinePlus

... kidney dialysis, blood transfusions, plasma replacement therapy. An experimental Ebola vaccine proved highly protective against Ebola virus ... Ebola. 13. Is there an Ebola vaccine? An experimental Ebola vaccine proved highly protective against the deadly ...

The Trans-Pacific Partnership Agreement

DTIC Science & Technology

2010-06-25

New Zealand may focus on agricultural goods such as beef and dairy products. The possible inclusion of Vietnam may prove controversial from the...sensitive U.S. agriculture sectors such as beef , lamb, and dairy products. U.S. goods trade with New Zealand is relatively small. New Zealand was...10 Dairy

Aggregate Stability of Tropical Soils Under Long-Term Eucalyptus Cultivation

USDA-ARS?s Scientific Manuscript database

Eucalyptus cultivation has increased in all Brazilian regions. Despite the large amount of cultivated area, little is known about how this kind of management system affects soil properties, mainly the aggregate stability. Aggregate stability analyses have proved to be a sensitive tool to measure soi...

The imprints of the high light and UV-B stresses in Oryza sativa L. 'Kanchana' seedlings are differentially modulated.

PubMed

Faseela, Parammal; Puthur, Jos T

2018-01-01

High light and ultraviolet-B radiation (UV-B) are generally considered to have negative impact on photosynthesis and plant growth. The present study evaluates the tolerance potential of three cultivars of Oryza sativa L. (Kanchana, Mattatriveni and Harsha) seedlings towards high light and UV-B stress on the basis of photosynthetic pigment degradation, chlorophyll a fluorescence parameters and rate of lipid peroxidation, expressed by malondialdehyde content. Surprisingly, it was revealed that Kanchana was the most sensitive cultivar towards high light and at the same time it was the most tolerant cultivar towards UV-B stress. This contrasting feature of Kanchana towards high light and UV-B tolerance was further studied by analyzing photosystem (PS) I and II activity, mitochondrial activity, chlorophyll a fluorescence transient, enzymatic and non-enzymatic antioxidant defense system. Due to the occurrence of more PS I and PSII damages, the inhibition of photochemical efficiency and emission of dissipated energy as heat or fluorescence per PSII reaction center was higher upon high light exposure than UV-B treatments in rice seedlings of Kanchana. The mitochondrial activity was also found to be drastically altered upon high light as compared to UV-B treatments. The UV-B induced accumulation of non-enzymatic antioxidants (proline, total phenolics, sugar and ascorbate) and enzymatic antioxidants (ascorbate peroxidase, guaiacol peroxidase, superoxide dismutase and glutathione reductase) in rice seedlings than those subjected to high light exposure afforded more efficient protection against UV-B radiation in rice seedlings. Our results proved that high tolerance of Kanchana towards UV-B than high light treatments, correlated linearly with the protected photosynthetic and mitochondrial machinery which was provided by upregulation of antioxidants particularly by total phenolics, ascorbate and ascorbate peroxidase in rice seedlings. Data presented in this study conclusively proved that rice cultivar Kanchana respond to different environmental signals independently and tolerance mechanisms to individual stress factors was also varied. Copyright © 2017 Elsevier B.V. All rights reserved.

Experimental assessment of advanced Stirling component concepts

NASA Technical Reports Server (NTRS)

Ziph, B.

1985-01-01

The results of an experimental assessment of some advanced Stirling engine component concepts are presented. High performance piston rings, reciprocating oil scrapers and heat pipes with getters and with mechanical couplings were tested. The tests yielded the following results: (1) Bonded, split, pumping piston rings, in preliminary testing, proved a promising concept, exhibiting low leakage and friction losses. Solid piston rings proved impractical in view of their sensitivity to the operating temperature; (2) A babbit oil scraper in a compliant housing performed well in atmospheric endurance testing. In pressurized tests the scraper did not perform well as a containment seal. The latter tests suggest modifications which may adapt Ti successfully to that application; and (3) Heat pipe endurance tests indicated the adequacy of simple, inexpensive fabrication and filling procedures. Getters were provided to increase the tolerance of the heat pipes to the presence of air and commercially available couplings were demonstrated to be suitable for heat pipe application. In addition to the above tests, the program also included a design effort for a split shaft applicable to a swashplate driven engine with a pressurized crank-case. The design is aimed, and does accomplish, an increase in component life to more than 10,000 hours.

A facile precursor route to highly loaded metal/ceramic nanofibers as a robust surface-enhanced Raman template

NASA Astrophysics Data System (ADS)

Park, Jay Hoon; Joo, Yong Lak

2017-09-01

We report silver (Ag)/ceramic nanofibers with highly robust and sensitive optical sensory capabilities that can withstand harsh conditions. These nanofibers are fabricated by first electrospinning solutions of poly vinyl alcohol (PVA) and metal precursor polymers, followed by subsequent series of heat treatment. The reported fabrication method demonstrate the effects of (i) the location of Ag crystals, (ii) crystal size and shape, and (iii) constituents of the ceramic matrix as surface-enhanced Raman spectroscopy (SERS) templates with 10-6 M 4-mercaptobenzoic acid (4-MBA). Notably, these silver/ceramic nanofibers preserved most of their highly sensitive localized surface plasmon resonance (LSPR) even under high temperature of 400 °C, in contrast to preformed Ag nanoparticles (NPs) in PVA nanofibers which lost most of its optical property presumably due to (i) Ag oxidation and (ii) loss of the matrix material. Among the ceramic substrates of ZrO2, Al2O3, and ZnO with silver crystals, we discovered that the ZnO substrate showed the most consistent and the strongest signal strength owing to the synergistic chemical and optical properties of the ZnO substrate. Moreover, the pure Ag nanofiber proved to be the best heat-resistant SERS template, owing to its (i) anisotropic morphology and (ii) thicker diameter when compared with other conventional Ag nanomaterials. These results demonstrated simple yet highly controllable fabrication of robust SERS templates, with potential applications in a catalytic sensory which is often exposed to harsh conditions.

Withanolide E sensitizes renal carcinoma cells to TRAIL-induced apoptosis by increasing cFLIP degradation.

PubMed

Henrich, C J; Brooks, A D; Erickson, K L; Thomas, C L; Bokesch, H R; Tewary, P; Thompson, C R; Pompei, R J; Gustafson, K R; McMahon, J B; Sayers, T J

2015-02-26

Withanolide E, a steroidal lactone from Physalis peruviana, was found to be highly active for sensitizing renal carcinoma cells and a number of other human cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. Withanolide E, the most potent and least toxic of five TRAIL-sensitizing withanolides identified, enhanced death receptor-mediated apoptotic signaling by a rapid decline in the levels of cFLIP proteins. Other mechanisms by which TRAIL sensitizers have been reported to work: generation of reactive oxygen species (ROS), changes in pro-and antiapoptotic protein expression, death receptor upregulation, activation of intrinsic (mitochondrial) apoptotic pathways, ER stress, and proteasomal inhibition proved to be irrelevant to withanolide E activity. Loss of cFLIP proteins was not due to changes in expression, but rather destabilization and/or aggregation, suggesting impairment of chaperone proteins leading to degradation. Indeed, withanolide E treatment altered the stability of a number of HSP90 client proteins, but with greater apparent specificity than the well-known HSP90 inhibitor geldanamycin. As cFLIP has been reported to be an HSP90 client, this provides a potentially novel mechanism for sensitizing cells to TRAIL. Sensitization of human renal carcinoma cells to TRAIL-induced apoptosis by withanolide E and its lack of toxicity were confirmed in animal studies. Owing to its novel activity, withanolide E is a promising reagent for the analysis of mechanisms of TRAIL resistance, for understanding HSP90 function, and for further therapeutic development. In marked contrast to bortezomib, among the best currently available TRAIL sensitizers, withanolide E's more specific mechanism of action suggests minimal toxic side effects.

Withanolide E sensitizes renal carcinoma cells to TRAIL-induced apoptosis by increasing cFLIP degradation

PubMed Central

Henrich, C J; Brooks, A D; Erickson, K L; Thomas, C L; Bokesch, H R; Tewary, P; Thompson, C R; Pompei, R J; Gustafson, K R; McMahon, J B; Sayers, T J

2015-01-01

Withanolide E, a steroidal lactone from Physalis peruviana, was found to be highly active for sensitizing renal carcinoma cells and a number of other human cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. Withanolide E, the most potent and least toxic of five TRAIL-sensitizing withanolides identified, enhanced death receptor-mediated apoptotic signaling by a rapid decline in the levels of cFLIP proteins. Other mechanisms by which TRAIL sensitizers have been reported to work: generation of reactive oxygen species (ROS), changes in pro-and antiapoptotic protein expression, death receptor upregulation, activation of intrinsic (mitochondrial) apoptotic pathways, ER stress, and proteasomal inhibition proved to be irrelevant to withanolide E activity. Loss of cFLIP proteins was not due to changes in expression, but rather destabilization and/or aggregation, suggesting impairment of chaperone proteins leading to degradation. Indeed, withanolide E treatment altered the stability of a number of HSP90 client proteins, but with greater apparent specificity than the well-known HSP90 inhibitor geldanamycin. As cFLIP has been reported to be an HSP90 client, this provides a potentially novel mechanism for sensitizing cells to TRAIL. Sensitization of human renal carcinoma cells to TRAIL-induced apoptosis by withanolide E and its lack of toxicity were confirmed in animal studies. Owing to its novel activity, withanolide E is a promising reagent for the analysis of mechanisms of TRAIL resistance, for understanding HSP90 function, and for further therapeutic development. In marked contrast to bortezomib, among the best currently available TRAIL sensitizers, withanolide E's more specific mechanism of action suggests minimal toxic side effects. PMID:25719250

Dual core quantum dots for highly quantitative ratiometric detection of trypsin activity in cystic fibrosis patients

NASA Astrophysics Data System (ADS)

Castelló Serrano, Iván; Stoica, Georgiana; Matas Adams, Alba; Palomares, Emilio

2014-10-01

We present herein two colour encoded silica nanospheres (2nanoSi) for the fluorescence quantitative ratiometric determination of trypsin in humans. Current detection methods for cystic fibrosis diagnosis are slow, costly and suffer from false positives. The 2nanoSi proved to be a highly sensitive, fast (minutes), and single-step approach nanosensor for the screening and diagnosis of cystic fibrosis, allowing the quantification of trypsin concentrations in a wide range relevant for clinical applications (25-350 μg L-1). Furthermore, as trypsin is directly related to the development of cystic fibrosis (CF), different human genotypes, i.e. CF homozygotic, CF heterozygotic, and unaffected, respectively, can be determined using our 2nanoSi nanospheres. We anticipate the 2nanoSi system to be a starting point for non-invasive, easy-to-use and cost effective ratiometric fluorescent biomarkers for recessive genetic diseases like human cystic fibrosis. In a screening program in which the goal is to detect disease and also the carrier status, early diagnosis could be of great help.We present herein two colour encoded silica nanospheres (2nanoSi) for the fluorescence quantitative ratiometric determination of trypsin in humans. Current detection methods for cystic fibrosis diagnosis are slow, costly and suffer from false positives. The 2nanoSi proved to be a highly sensitive, fast (minutes), and single-step approach nanosensor for the screening and diagnosis of cystic fibrosis, allowing the quantification of trypsin concentrations in a wide range relevant for clinical applications (25-350 μg L-1). Furthermore, as trypsin is directly related to the development of cystic fibrosis (CF), different human genotypes, i.e. CF homozygotic, CF heterozygotic, and unaffected, respectively, can be determined using our 2nanoSi nanospheres. We anticipate the 2nanoSi system to be a starting point for non-invasive, easy-to-use and cost effective ratiometric fluorescent biomarkers for recessive genetic diseases like human cystic fibrosis. In a screening program in which the goal is to detect disease and also the carrier status, early diagnosis could be of great help. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03952a

Conical differentiability for evolution variational inequalities

NASA Astrophysics Data System (ADS)

Jarušek, Jiří; Krbec, Miroslav; Rao, Murali; Sokołowski, Jan

The conical differentiability of solutions to the parabolic variational inequality with respect to the right-hand side is proved in the paper. From one side the result is based on the Lipschitz continuity in H {1}/{2},1 (Q) of solutions to the variational inequality with respect to the right-hand side. On the other side, in view of the polyhedricity of the convex cone K={v∈ H;v |Σ c⩾0,v |Σ d=0}, we prove new results on sensitivity analysis of parabolic variational inequalities. Therefore, we have a positive answer to the question raised by Fulbert Mignot (J. Funct. Anal. 22 (1976) 25-32).

Sensitive Spin Detection Using An On-Chip Squid-Waveguide Resonator

NASA Astrophysics Data System (ADS)

Yue, Guang

Quantum computing gives novel way of computing using quantum mechanics, which furthers human knowledge and has exciting applications. Quantum systems with diluted spins such as rare earth ions hosted in single crystal, molecule-based magnets etc. are promising qubits candidates to form the basis of a quantum computer. High sensitivity measurement and coherent control of these spin systems are crucial for their practical usage as qubits. The micro-SQUID (direct-current micrometer-sized Superconducting QUantum Interference Device) is capable to measure magnetization of spin system with high sensitivity. For example, the micro-SQUID technique can measure magnetic moments as small as several thousand muB as shown by the study of [W. Wernsdorfer, Supercond. Sci. Technol. 22, 064013 (2009)]. Here we develop a novel on-chip setup that combines the micro-SQUID sensitivity with microwave excitation. Such setup can be used for electron spin resonance measurements or coherent control of spins utilizing the high sensitivity of micro-SQUID for signal detection. To build the setup, we studied the fabrication process of the micro-SQUID, which is made of weak-linked Josephson junctions. The SQUID as a detector is integrated on the same chip with a shorted coplanar waveguide, so that the microwave pulses can be applied through the waveguide to excite the sample for resonance measurements. The whole device is plasma etched from a thin (˜ 20nm) niobium film, so that the SQUID can work at in large in-plane magnetic fields of several tesla. In addition, computer simulations are done to find the best design of the waveguide such that the microwave excitation field is sufficiently strong and uniformly applied to the sample. The magnetization curve of Mn12 molecule-based magnet sample is measured to prove the proper working of the micro-SQUID. Electron spin resonance measurement is done on the setup for gadolinium ions diluted in a CaWO4 single crystal. The measurement shows clear evidence of the resonance signal from the 1st transition of the gadolinium ions' energy levels, which shows the setup is successfully built. Due to the high sensitivity of micro-SQUID and the ability to concentrate microwave energy in small areas of the chip, this setup can detect signals from a small number of spins (107) in a small volume (several mum 3).

The Trans-Pacific Partnership Agreement

DTIC Science & Technology

2010-04-14

New Zealand may focus on agricultural goods such as beef and dairy products. The possible inclusion of Vietnam may prove controversial from the...on sensitive U.S. agriculture sectors such as beef , lamb, and dairy products. U.S. goods trade with New Zealand is relatively small. New Zealand was...10 Dairy

Ground and excited state properties of high performance anthocyanidin dyes-sensitized solar cells in the basic solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prima, Eka Cahya; Computational Material Design and Quantum Engineering Laboratory, Engineering Physics, Institut Teknologi Bandung; International Program on Science Education, Universitas Pendidikan Indonesia

2015-09-30

The aglycones of anthocyanidin dyes were previously reported to form carbinol pseudobase, cis-chalcone, and trans-chalcone due to the basic levels. The further investigations of ground and excited state properties of the dyes were characterized using density functional theory with PCM(UFF)/B3LYP/6-31+G(d,p) level in the basic solutions. However, to the best of our knowledge, the theoretical investigation of their potential photosensitizers has never been reported before. In this paper, the theoretical photovoltaic properties sensitized by dyes have been successfully investigated including the electron injections, the ground and excited state oxidation potentials, the estimated open circuit voltages, and the light harvesting efficiencies. Themore » results prove that the electronic properties represented by dyes’ LUMO-HOMO levels will affect to the photovoltaic performances. Cis-chalcone dye is the best anthocyanidin aglycone dye with the electron injection spontaneity of −1.208 eV, the theoretical open circuit voltage of 1.781 V, and light harvesting efficiency of 56.55% due to the best HOMO-LUMO levels. Moreover, the ethanol solvent slightly contributes to the better cell performance than the water solvent dye because of the better oxidation potential stabilization in the ground state as well as in the excited state. These results are in good agreement with the known experimental report that the aglycones of anthocyanidin dyes in basic solvent are the high potential photosensitizers for dye-sensitized solar cell.« less

Wavefront division digital holography

NASA Astrophysics Data System (ADS)

Zhang, Wenhui; Cao, Liangcai; Li, Rujia; Zhang, Hua; Zhang, Hao; Jiang, Qiang; Jin, Guofan

2018-05-01

Digital holography (DH), mostly Mach-Zehnder configuration based, belongs to non-common path amplitude splitting interference imaging whose stability and fringe contrast are environmental sensitive. This paper presents a wavefront division DH configuration with both high stability and high-contrast fringes benefitting from quasi common path wavefront-splitting interference. In our proposal, two spherical waves with similar curvature coming from the same wavefront are used, which makes full use of the physical sampling capacity of the detectors. The interference fringe spacing can be adjusted flexibly for both in-line and off-axis mode due to the independent modulation to these two waves. Only a few optical elements, including the mirror-beam splitter interference component, are used without strict alignments, which makes it robust and easy-to-implement. The proposed wavefront division DH promotes interference imaging physics into the practical and miniaturized a step forward. The feasibility of this method is proved by the imaging of a resolution target and a water flea.

Computed tomography and magnetic resonance imaging in diagnosing hepatocellular carcinoma.

PubMed

Dalla Palma, L; Pozzi-Mucelli, R S

1992-02-01

The evaluation of hepatocellular carcinoma (HCC) is based upon ultrasonography (US) which has proved to have a high sensitivity and is also extremely useful in guiding the percutaneous needle biopsy. The main role of computed tomography (CT) and magnetic resonance imaging (MRI) is to supplement US in evaluating the extent of HCC. The Authors discuss the different techniques of examinations of the liver both for CT and MRI as far as the modalities of contrast enhancement, site of injection, and type of contrast agents are concerned. The differences between low field and high field magnets are also discussed. The main CT and MRI findings are illustrated, depending upon the technique of examination. Finally the role of these techniques is discussed. Based upon personal experience and the data in CT literature, and if performed with updated technology and intraarterial injection (lipiodol), CT is the method of choice in order to supplement US in the evaluation of HCC.

Almeria spatial memory recognition test (ASMRT): Gender differences emerged in a new passive spatial task.

PubMed

Tascón, Laura; García-Moreno, Luis Miguel; Cimadevilla, Jose Manuel

2017-06-09

Many different human spatial memory tasks were developed in the last two decades. Virtual reality based tasks make possible developing different scenarios and situations to assess spatial orientation but sometimes these tasks are complex for specific populations like children and older-adults. A new spatial task with a very limited technological requirement was developed in this study. It demanded the use of spatial memory for an accurate solution. It also proved to be sensitive to gender differences, with men outperforming women under high specific difficulty levels. Thanks to its simplicity it could be applied as a screening test and is easy to combine with EEG and fMRI studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Designed to dissolve: suppression of colloidal aggregation of Cu(I)-selective fluorescent probes in aqueous buffer and in-gel detection of a metallochaperone.

PubMed

Morgan, M Thomas; Bagchi, Pritha; Fahrni, Christoph J

2011-10-12

Due to the lipophilicity of the metal-ion receptor, previously reported Cu(I)-selective fluorescent probes form colloidal aggregates, as revealed by dynamic light scattering. To address this problem, we have developed a hydrophilic triarylpyrazoline-based fluorescent probe, CTAP-2, that dissolves directly in water and shows a rapid, reversible, and highly selective 65-fold fluorescence turn-on response to Cu(I) in aqueous solution. CTAP-2 proved to be sufficiently sensitive for direct in-gel detection of Cu(I) bound to the metallochaperone Atox1, demonstrating the potential for cation-selective fluorescent probes to serve as tools in metalloproteomics for identifying proteins with readily accessible metal-binding sites.

From thermometric to spectrophotometric kinetic-catalytic methods of analysis. A review.

PubMed

Cerdà, Víctor; González, Alba; Danchana, Kaewta

2017-05-15

Kinetic-catalytic analytical methods have proved to be very easy and highly sensitive strategies for chemical analysis, that rely on simple instrumentation [1,2]. Molecular absorption spectrophotometry is commonly used as the detection technique. However, other detection systems, like electrochemical or thermometric ones, offer some interesting possibilities since they are not affected by the color or turbidity of the samples. In this review some initial experience with thermometric kinetic-catalytic methods is described, up to our current experience exploiting spectrophotometric flow techniques to automate this kind of reactions, including the use of integrated chips. Procedures for determination of inorganic and organic species in organic and inorganic matrices are presented. Copyright © 2017 Elsevier B.V. All rights reserved.

A reversible fluorescence "off-on-off" sensor for sequential detection of aluminum and acetate/fluoride ions.

PubMed

Gupta, Vinod Kumar; Mergu, Naveen; Kumawat, Lokesh Kumar; Singh, Ashok Kumar

2015-11-01

A new rhodamine functionalized fluorogenic Schiff base CS was synthesized and its colorimetric and fluorescence responses toward various metal ions were explored. The sensor exhibited highly selective and sensitive colorimetric and "off-on" fluorescence response towards Al(3+) in the presence of other competing metal ions. These spectral changes are large enough in the visible region of the spectrum and thus enable naked-eye detection. Studies proved that the formation of CS-Al(3+) complex is fully reversible and can sense to AcO(-)/F(-) via dissociation. The results revealed that the sensor provides fluorescence "off-on-off" strategy for the sequential detection of Al(3+) and AcO(-)/F(-). Copyright © 2015 Elsevier B.V. All rights reserved.

[Construction and application of an onboard absorption analyzer device for CDOM].

PubMed

Lin, Jun-Fang; Sun, Zhao-Hua; Cao, Wen-Xi; Hu, Shui-Bo; Xu, Zhan-Tang

2013-04-01

Colored dissolved organic matter (CDOM) plays an important role in marine ecosystems. In order to solve the current problems in measurement of CDOM absorption, an automated onboard analyzer based on liquid core waveguides (Teflon AF LWCC/LCW) was constructed. This analyzer has remarkable characteristics including adjusted optical pathlength, wide measurement range, and high sensitivity. The model of filtration and injection can implement the function of automated filtration, sample injection, and LWCC cleaning. The LabVIEW software platform can efficiently control the running state of the analyzer and acquire real time data including light absorption spectra, GPS data, and CTW data. By the comparison experiments and shipboard measurements, it was proved that the analyzer was reliable and robust.

A more sensitive, efficient and ISO 17025 validated Magnetic Capture real time PCR method for the detection of archetypal Toxoplasma gondii strains in meat.

PubMed

Gisbert Algaba, Ignacio; Geerts, Manon; Jennes, Malgorzata; Coucke, Wim; Opsteegh, Marieke; Cox, Eric; Dorny, Pierre; Dierick, Katelijne; De Craeye, Stéphane

2017-11-01

Toxoplasma gondii is a globally prevalent, zoonotic parasite of major importance to public health. Various indirect and direct methods can be used for the diagnosis of toxoplasmosis. Whereas serological tests are useful to prove contact with the parasite has occurred, the actual presence of the parasite in the tissues of a seropositive animal is not demonstrated. For this, a bioassay is still the reference method. As an alternative, various PCR methods have been developed, but due to the limited amount of sample that can be tested, combined with a low tissue cyst density, those have proved to be insufficiently sensitive. A major improvement of the sensitivity was achieved with magnetic capture-based DNA extraction. By combining the hybridization of specific, biotinylated probes with the capture of those probes with streptavidin-coated paramagnetic beads, T. gondii DNA can selectively be "fished out" from a large volume of meat lysate. Still, several studies showed an insufficient sensitivity compared with the mouse bioassay. Here we present a method that is more sensitive (99% limit of detection: 65.4 tachyzoites per 100g of meat), economical and reliable (ISO 17025 validated) by adding a non-competitive PCR inhibition control (co-capture of cellular r18S) and making the release of the target DNA from the streptavidin-coated paramagnetic beads UV-dependent. The presented results demonstrate the potential of the modified Magnetic Capture real time PCR as a full alternative to the mouse bioassay for the screening of various types of tissues and meat, with the additional advantage of being quantitative. Copyright © 2017 Australian Society for Parasitology. Published by Elsevier Ltd. All rights reserved.

Electronic and optoelectronic device applications based on ReS2

NASA Astrophysics Data System (ADS)

Liu, Erfu; Long, Mingsheng; Wang, Yaojia; Pan, Yiming; Ho, Chinghwa; Wang, Baigeng; Miao, Feng

Rhenium disulfide (ReS2) is a unique semiconducting TMD with distorted 1T structure and weak interlayer coupling. We have previously investigated its in-plane anisotropic property and electronic applications on FET and digital inverters. In this talk, we will present high responsivity phototransistors based on few-layer ReS2. Depending on the back gate voltage, source drain bias and incident optical light intensity, the maximum attainable photoresponsivity can reach as high as 88,600 A W-1, which is one of the highest value among individual two-dimensional materials with similar device structures. Such high photoresponsivity is attributed to the increased light absorption as well as the gain enhancement due to the existence of trap states in the few-layer ReS2 flakes. The existence of trap states is proved by temperature dependent transport measurements. It further enables the detection of weak signals. Our studies underscore ReS2 as a promising material for future electronic and sensitive optoelectronic applications.

Scanning micro-resonator direct-comb absolute spectroscopy

PubMed Central

Gambetta, Alessio; Cassinerio, Marco; Gatti, Davide; Laporta, Paolo; Galzerano, Gianluca

2016-01-01

Direct optical Frequency Comb Spectroscopy (DFCS) is proving to be a fundamental tool in many areas of science and technology thanks to its unique performance in terms of ultra-broadband, high-speed detection and frequency accuracy, allowing for high-fidelity mapping of atomic and molecular energy structure. Here we present a novel DFCS approach based on a scanning Fabry-Pérot micro-cavity resonator (SMART) providing a simple, compact and accurate method to resolve the mode structure of an optical frequency comb. The SMART approach, while drastically reducing system complexity, allows for a straightforward absolute calibration of the optical-frequency axis with an ultimate resolution limited by the micro-resonator resonance linewidth and can be used in any spectral region from UV to THz. We present an application to high-precision spectroscopy of acetylene at 1.54 μm, demonstrating performances comparable or even better than current state-of-the-art DFCS systems in terms of sensitivity, optical bandwidth and frequency-resolution. PMID:27752132

Analysis and implementation of a space resolving spherical crystal spectrometer for x-ray Thomson scattering experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Harding, E. C.; Ao, T.; Bailey, J. E.

2015-04-15

The application of a space-resolving spectrometer to X-ray Thomson Scattering (XRTS) experiments has the potential to advance the study of warm dense matter. This has motivated the design of a spherical crystal spectrometer, which is a doubly focusing geometry with an overall high sensitivity and the capability of providing high-resolution, space-resolved spectra. A detailed analysis of the image fluence and crystal throughput in this geometry is carried out and analytical estimates of these quantities are presented. This analysis informed the design of a new spectrometer intended for future XRTS experiments on the Z-machine. The new spectrometer collects 6 keV x-raysmore » with a spherically bent Ge (422) crystal and focuses the collected x-rays onto the Rowland circle. The spectrometer was built and then tested with a foam target. The resulting high-quality spectra prove that a spherical spectrometer is a viable diagnostic for XRTS experiments.« less

Analysis and implementation of a space resolving spherical crystal spectrometer for x-ray Thomson scattering experiments.

PubMed

Harding, E C; Ao, T; Bailey, J E; Loisel, G; Sinars, D B; Geissel, M; Rochau, G A; Smith, I C

2015-04-01

The application of a space-resolving spectrometer to X-ray Thomson Scattering (XRTS) experiments has the potential to advance the study of warm dense matter. This has motivated the design of a spherical crystal spectrometer, which is a doubly focusing geometry with an overall high sensitivity and the capability of providing high-resolution, space-resolved spectra. A detailed analysis of the image fluence and crystal throughput in this geometry is carried out and analytical estimates of these quantities are presented. This analysis informed the design of a new spectrometer intended for future XRTS experiments on the Z-machine. The new spectrometer collects 6 keV x-rays with a spherically bent Ge (422) crystal and focuses the collected x-rays onto the Rowland circle. The spectrometer was built and then tested with a foam target. The resulting high-quality spectra prove that a spherical spectrometer is a viable diagnostic for XRTS experiments.

Corona discharge detection based on UV pulse method

NASA Astrophysics Data System (ADS)

Zhao, Taifei; Lei, Yangfei; Hou, Peng

2016-03-01

With the reforming and opening up, as well as the rapid economic development of china, the shortage of electricity resources in the eastern region has become a problem. Therefore, we have started the program of power transmission from west to east, and have speeding up the development of high-voltage transmission technologies with high efficiency, long-distance, and high-capacity. An important issue during the power transmission is the insulation design. Recently, there have been more and more power grid accidents are escalating. Therefore, timely discovering an forecasting insulation deteriorations using advance detection techniques is of special practical significance for the equipment maintenance and repairing , and especially avoiding power accidents. On this basis, this paper carries out the research of high-voltage transmission line corona discharge detection system using the solar blind and FPGA. The experimental result shows that our system can amplify week signals with different intensity of 5100 5000100 times, with high sensitivity and anti-interference ability. The result also proves that this system can effectively detect the ultraviolet pulse light signal of the corona discharge insulation.

Coupling the Torpedo microplate-receptor binding assay with mass spectrometry to detect cyclic imine neurotoxins.

PubMed

Aráoz, Rómulo; Ramos, Suzanne; Pelissier, Franck; Guérineau, Vincent; Benoit, Evelyne; Vilariño, Natalia; Botana, Luis M; Zakarian, Armen; Molgó, Jordi

2012-12-04

Cyclic imine neurotoxins constitute an emergent family of neurotoxins of dinoflagellate origin that are potent antagonists of nicotinic acetylcholine receptors. We developed a target-directed functional method based on the mechanism of action of competitive agonists/antagonists of nicotinic acetylcholine receptors for the detection of marine cyclic imine neurotoxins. The key step for method development was the immobilization of Torpedo electrocyte membranes rich in nicotinic acetylcholine receptors on the surface of microplate wells and the use of biotinylated-α-bungarotoxin as tracer. Cyclic imine neurotoxins competitively inhibit biotinylated-α-bungarotoxin binding to Torpedo-nicotinic acetylcholine receptors in a concentration-dependent manner. The microplate-receptor binding assay allowed rapid detection of nanomolar concentrations of cyclic imine neurotoxins directly in shellfish samples. Although highly sensitive and specific for the detection of neurotoxins targeting nicotinic acetylcholine receptors as a class, the receptor binding assay cannot identify a given analyte. To address the low selectivity of the microplate-receptor binding assay, the cyclic imine neurotoxins tightly bound to the coated Torpedo nicotinic receptor were eluted with methanol, and the chemical nature of the eluted ligands was identified by mass spectrometry. The immobilization of Torpedo electrocyte membranes on the surface of microplate wells proved to be a high-throughput format for the survey of neurotoxins targeting nicotinic acetylcholine receptors directly in shellfish matrixes with high sensitivity and reproducibility.

Transitiometric analysis of solid II/solid I transition in anhydrous theophylline.

PubMed

Legendre, Bernard; Randzio, Stanislaw L

2007-10-01

For the first time, with the use of a high sensitivity, low heating rate, scanning transitiometry, it was possible to distinguish and characterise the polymorphic equilibrium transition between forms II and I in anhydrous theophylline. In this manner it was univocally proved, that forms II and I in theophylline are enantiotropically related. The temperature and enthalpy for that transition are as follows: T(trs)(II/I)=536.8+/-2.2K; Delta(trs)H(II/I)=1.99+/-0.09 kJ/mol. Making use of advantages of very slow heating rate and of a high energetic sensitivity of the transitiometer it was possible to observe in detail the polymorphic transition followed by melting of high temperature form I and to stop the solid I-liquid transition at a desired point of equilibrium. Such a solid I-liquid equilibrium could be stabilised and then displaced back to the crystallisation of form I with an adequate use of a precise temperature programming. In such a way a pure single phase of form I of theophylline was prepared. This fact was confirmed by X-ray powder diffraction patterns and calorimetric traces of fusion of the crystallised product. The temperature and enthalpy of the form I-liquid transition are as follows: T(fus)(I)=546.5+/-0.2K and Delta(fus)H(I)=29.37+/-0.29 kJ/mol.

Laser Scanning System for Pressure and Temperature Paints

NASA Technical Reports Server (NTRS)

Sullivan, John

1997-01-01

Acquiring pressure maps of aerodynamic surfaces is very important for improving and validating the performance of aerospace vehicles. Traditional pressure measurements are taken with pressure taps embedded in the model surface that are connected to transducers. While pressure taps allow highly accurate measurements to be acquired, they do have several drawbacks. Pressure taps do not give good spatial resolution due to the need for individual pressure tubes, compounded by limited space available inside models. Also, building a model proves very costly if taps are needed because of the large amount of labor necessary to drill, connect and test each one. The typical cost to install one tap is about $200. Recently, a new method for measuring pressure on aerodynamic surfaces has been developed utilizing a technology known as pressure sensitive paints (PSP). Using PSP, pressure distributions can be acquired optically with high spatial resolution and simple model preparation. Flow structures can be easily visualized using PSP, but are missed using low spatial resolution arrays of pressure taps. PSP even allows pressure distributions to be found on rotating machinery where previously this has been extremely difficult or even impossible. The goal of this research is to develop a laser scanning system for use with pressure sensitive paints that allows accurate pressure measurements to be obtained on various aerodynamic surfaces ranging from wind tunnel models to high speed jet engine compressor blades.

Coupling the Torpedo Microplate-Receptor Binding Assay with Mass Spectrometry to Detect Cyclic Imine Neurotoxins

PubMed Central

Aráoz, Rómulo; Ramos, Suzanne; Pelissier, Franck; Guérineau, Vincent; Benoit, Evelyne; Vilariño, Natalia; Botana, Luis M.; Zakarian, Armen; Molgó, Jordi

2014-01-01

Cyclic imine neurotoxins constitute an emergent family of neurotoxins of dinoflagellate origin that are potent antagonists of nicotinic acetylcholine receptors. We developed a target-directed functional method based on the mechanism of action of competitive agonists/antagonists of nicotinic acetylcholine receptors for the detection of marine cyclic imine neurotoxins. The key step for method development was the immobilization of Torpedo electrocyte membranes rich in nicotinic acetylcholine receptors on the surface of microplate wells and the use of biotinylated-α-bungarotoxin as tracer. Cyclic imine neurotoxins competitively inhibit biotinylated-α-bungarotoxin binding to Torpedo-nicotinic acetylcholine receptors in a concentration-dependent manner. The microplate-receptor binding assay allowed rapid detection of nanomolar concentrations of cyclic imine neurotoxins directly in shellfish samples. Although highly sensitive and specific for the detection of neurotoxins targeting nicotinic acetylcholine receptors as a class, the receptor binding assay cannot identify a given analyte. To address the low selectivity of the microplate-receptor binding assay, the cyclic imine neurotoxins tightly bound to the coated Torpedo nicotinic receptor were eluted with methanol, and the chemical nature of the eluted ligands was identified by mass spectrometry. The immobilization of Torpedo electrocyte membranes on the surface of microplate wells proved to be a high-throughput format for the survey of neurotoxins targeting nicotinic acetylcholine receptors directly in shellfish matrixes with high sensitivity and reproducibility. PMID:23131021

Scale-Up of the Electrodeposition of ZnO/Eosin Y Hybrid Thin Films for the Fabrication of Flexible Dye-Sensitized Solar Cell Modules.

PubMed

Bittner, Florian; Oekermann, Torsten; Wark, Michael

2018-02-02

The low-temperature fabrication of flexible ZnO photo-anodes for dye-sensitized solar cells (DSSCs) by templated electrochemical deposition of films was performed in an enlarged and technical simplified deposition setup to demonstrate the feasibility of the scale-up of the deposition process. After extraction of eosin Y (EY) from the initially deposited ZnO/EY hybrid films, mesoporous ZnO films with an area of about 40 cm² were reproducibly obtained on fluorine doped tin oxide (FTO)-glass as well as flexible indium tin oxide (ITO)-polyethylenterephthalate (PET) substrates. With a film thickness of up to 9 µm and a high specific surface area of up to about 77 m²·cm -3 the ZnO films on the flexible substrates show suitable properties for DSSCs. Operative flexible DSSC modules proved the suitability of the ZnO films for use as DSSC photo-anodes. Under a low light intensity of about 0.007 sun these modules achieved decent performance parameters with conversion efficiencies of up to 2.58%. With rising light intensity the performance parameters deteriorated, leading to conversion efficiencies below 1% at light intensities above 0.5 sun. The poor performance of the modules under high light intensities can be attributed to their high series resistances.

Scale-Up of the Electrodeposition of ZnO/Eosin Y Hybrid Thin Films for the Fabrication of Flexible Dye-Sensitized Solar Cell Modules

PubMed Central

Oekermann, Torsten

2018-01-01

The low-temperature fabrication of flexible ZnO photo-anodes for dye-sensitized solar cells (DSSCs) by templated electrochemical deposition of films was performed in an enlarged and technical simplified deposition setup to demonstrate the feasibility of the scale-up of the deposition process. After extraction of eosin Y (EY) from the initially deposited ZnO/EY hybrid films, mesoporous ZnO films with an area of about 40 cm2 were reproducibly obtained on fluorine doped tin oxide (FTO)-glass as well as flexible indium tin oxide (ITO)–polyethylenterephthalate (PET) substrates. With a film thickness of up to 9 µm and a high specific surface area of up to about 77 m2·cm−3 the ZnO films on the flexible substrates show suitable properties for DSSCs. Operative flexible DSSC modules proved the suitability of the ZnO films for use as DSSC photo-anodes. Under a low light intensity of about 0.007 sun these modules achieved decent performance parameters with conversion efficiencies of up to 2.58%. With rising light intensity the performance parameters deteriorated, leading to conversion efficiencies below 1% at light intensities above 0.5 sun. The poor performance of the modules under high light intensities can be attributed to their high series resistances. PMID:29393910

Dual-hologram shearing interference technique with regulated sensitivity

NASA Astrophysics Data System (ADS)

Toker, Gregory R.; Levin, Daniel

1998-06-01

A novel optical diagnostic technique,namely, a dual hologram shearing interferometry with regulated sensitivity, is proposed for visualization and measuring the density gradients of compressible flows in wind tunnels. It has advantages over conventional shearing interferometry in both accuracy and sensitivity. The method is especially useful for strong turbulent or unsteady regions of the flows including shock flows. The interferometer proved to be insensitive to mechanical vibrations and allowed to record holograms during the noisy wind tunnel run. The proposed approach was demonstrated by its application to a supersonic flow over spherically blunted and sharp nose cone/cylinder models. It is believed that the technique will become an effective tool for receiving optical data in many flow facilities.

Dual-hologram shearing interferometry with regulated sensitivity

NASA Astrophysics Data System (ADS)

Toker, Gregory R.; Levin, Daniel

1998-07-01

A novel optical diagnostic technique, namely, a dual hologram shearing interferometry with regulated sensitivity, is proposed for visualization and measuring the density gradients of compressible flows in wind tunnels. It has advantages over conventional shearing interferometry in both accuracy and sensitivity. The method is especially useful for strong turbulent or unsteady regions of the flows including shock flows. The interferometer proved to be insensitive to mechanical vibrations and allowed to record holograms during the noisy wind tunnel run. The proposed approach was demonstrated by its application to a supersonic flow over spherically blunted and sharp nose cone/cylinder models. It is believed that the technique will become an effective tool for receiving optical data in many flow facilities.

A cockspur for the DSS cells: Erythrina crista-galli sensitizers

NASA Astrophysics Data System (ADS)

Enciso, Paula; Decoppet, Jean-David; Grätzel, Michael; Wörner, Michael; Cabrerizo, Franco M.; Cerdá, María Fernanda

2017-04-01

Dye sensitized solar cells were assembled employing a mixture of anthocyanins extracted from red ceibo's flowers. At the literature different extraction procedures are reported to extract anthocyanins from natural products and sensitize the cells. In order to compare them, different methods were followed to set the cells under the same conditions. Assembled cells showed very interesting conversion efficiency values, reaching a 0.73% value for extracts purified using C18 column, in open cells under illumination using a solar light simulator, 1 sun, 1.5 AM. Data reported herein prove that anthocyanins obtained from ceibo's flower, after simple further purification, might represent an excellent, cheap and clean alternative for the development of DSS cells.

TriXY-Homogeneous genetic sexing of highly degraded forensic samples including hair shafts.

PubMed

Madel, Maria-Bernadette; Niederstätter, Harald; Parson, Walther

2016-11-01

Sexing of biological evidence is an important aspect in forensic investigations. A routinely used molecular-genetic approach to this endeavour is the amelogenin sex test, which is integrated in most commercially available polymerase chain reaction (PCR) kits for human identification. However, this assay is not entirely effective in respect to highly degraded DNA samples. This study presents a homogeneous PCR assay for robust sex diagnosis, especially for the analysis of severely fragmented DNA. The introduced triplex for the X and Y chromosome (TriXY) is based on real-time PCR amplification of short intergenic sequences (<50bp) on both gonosomes. Subsequent PCR product examination and molecular-genetic sex-assignment rely on high-resolution melting (HRM) curve analysis. TriXY was optimized using commercially available multi-donor human DNA preparations of either male or female origin and successfully evaluated on challenging samples, including 46 ancient DNA specimens from archaeological excavations and a total of 16 DNA samples extracted from different segments of eight hair shafts of male and female donors. Additionally, sensitivity and cross-species amplification were examined to further test the assay's utility in forensic investigations. TriXY's closed-tube format avoids post-PCR sample manipulations and, therefore, distinctly reduces the risk of PCR product carry-over contamination and sample mix-up, while reducing labour and financial expenses at the same time. The method is sensitive down to the DNA content of approximately two diploid cells and has proven highly useful on severely fragmented and low quantity ancient DNA samples. Furthermore, it even allowed for sexing of proximal hair shafts with very good results. In summary, TriXY facilitates highly sensitive, rapid, and costeffective genetic sex-determination. It outperforms existing sexing methods both in terms of sensitivity and minimum required template molecule lengths. Therefore, we feel confident that TriXY will prove to be a reliable addition to the toolbox currently used for sex-typing in forensic genetics and other fields of research. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Autonomous choices among deterministic evolution-laws as source of uncertainty

NASA Astrophysics Data System (ADS)

Trujillo, Leonardo; Meyroneinc, Arnaud; Campos, Kilver; Rendón, Otto; Sigalotti, Leonardo Di G.

2018-03-01

We provide evidence of an extreme form of sensitivity to initial conditions in a family of one-dimensional self-ruling dynamical systems. We prove that some hyperchaotic sequences are closed-form expressions of the orbits of these pseudo-random dynamical systems. Each chaotic system in this family exhibits a sensitivity to initial conditions that encompasses the sequence of choices of the evolution rule in some collection of maps. This opens a possibility to extend current theories of complex behaviors on the basis of intrinsic uncertainty in deterministic chaos.

Evaluating pesticide effects on freshwater invertebrate communities in alpine environment: a model ecosystem experiment.

PubMed

Ippolito, A; Carolli, M; Varolo, E; Villa, S; Vighi, M

2012-10-01

Pesticide loads in streams are potentially one of the most relevant stressors for macroinvertebrate communities. Nevertheless, real effects provoked at the community level are still largely unknown. Model ecosystems are frequently used as tools for the risk assessment of pesticides, especially for their regulation, however, they can be also applied to site-specific risk assessment in order to gain better understanding of the responses of aquatic ecosystems to chemical stress. In the present work, an experimental system was composed of 5 artificial streams that reproduced a mountain lotic environment under controlled conditions. This study was aimed to better understand, whether (and how) the biological community was influenced by pesticides pulse exposures. 5 mixture load events were simulated over the productive season (March-July 2010): biological community was regularly sampled and nominal concentrations of water were tested. The results were interpreted comparing the output of different metrics and statistical methodologies. The sensitivity of different metrics was analyzed considering single exposure events (maximum Toxic Units) as well as overall temporal trends. Results showed how some common taxonomic metrics (e.g. taxa richness, Shannon's index, total abundance of organisms, and the Extended Biotic Index) were not suitable to identify the effects of pesticides at community level. On the contrary EPT%, SPEAR(pesticide) and the Principal Response Curve methodology proved to be sensitive to this kind of stress, providing comparable results. Temporal trends of these metrics proved to be related to the concentration of chemicals. Remarkably, the first Principal Response Curve illustrates the trend followed by the most vulnerable species, while the second is more related to the trend of opportunistic species. A high potential risk for the invertebrate community was highlighted by a statistically significant decline of 40 points (comparison with the control) in both SPEAR(pesticide) and EPT%.

Intra-dialytic blood oxygen saturation (SO2): association with dialysis hypotension (the SOGLIA Study).

PubMed

Mancini, E; Perazzini, C; Gesualdo, L; Aucella, F; Limido, A; Scolari, F; Savoldi, S; Tramonti, M; Corazza, L; Atti, M; Severi, S; Bolasco, P; Santoro, A

2017-12-01

Intradialytic hypotension (IDH) has a dramatic impact on the main outcomes of dialysis patients. Early warning of hemodynamic worsening during dialysis would enable preventive measures to be taken. Blood oxygen saturation (SO 2 ) is used for hemodynamic monitoring in the critical care setting and may provide useful information about IDH onset. To evaluate whether short- and medium-term variations in the SO 2 signal (ST-SO 2var , MT-SO 2var ,) during dialysis are a predictor of IDH. In this 3-month observational cohort study, 51 hypotension-prone chronic hemodialysis (HD) patients, with vascular access by arteriovenous fistula (AVF) or central venous catheter (CVC), were enrolled. Continuous non-invasive blood SO 2 was monitored (fc = 0.2 Hz) by an optical sensor on the arterial line of the extracorporeal circulation; blood pressure (every 30 min), symptoms and their time of appearance were noted. Predictive power of IDH was expressed by the area under curve (AUC) sensitivity and specificity based on intradialytic variations in SO 2 . A total of 1290 HD sessions were analyzed. Overall, off-line ST-SO 2var analysis proved able to correctly predict IDH in 67 % of the sessions where IDH occurred. The best predictive performance was found in the presence of highly arterialized AVF (SO 2  > 95 %) (75 % sensitivity; AUC 0.825; p < 0.05). On the contrary, in sessions with CVC, IDH prediction proved more efficient by MT-SO 2var (AUC 0.575; p = 0.01). Intradialytic SO 2 variability could be a valid parameter to detect in advance the hemodynamic worsening that precedes IDH. Appropriate timely intervention could help prevent IDH onset.

Serodiagnosis of infectious mononucleosis by using recombinant Epstein-Barr virus antigens and enzyme-linked immunosorbent assay technology.

PubMed Central

Gorgievski-Hrisoho, M; Hinderer, W; Nebel-Schickel, H; Horn, J; Vornhagen, R; Sonneborn, H H; Wolf, H; Siegl, G

1990-01-01

Four recombinant, diagnostically useful Epstein-Barr virus (EBV) proteins representative of the viral capsid antigen (p150), diffuse early antigen (p54), the major DNA-binding protein (p138), and the EBV nuclear antigen (p72) (W. Hinderer, H. Nebel-Schickel, H.H. Sonneborn, M. Motz, R. Kühbeck, and H. Wolf, J. Exp. Clin. Cancer Res. 7[Suppl.]:132, 1988) were used to set up individual enzyme-linked immunosorbent assays (ELISAs) for the qualitative and quantitative detection of immunoglobulin M (IgM) and IgG antibodies. In direct comparison with results obtained by standard immunofluorescence or immunoperoxidase assays, it was then shown that the recombinant EBV ELISAs provide the means for specific and sensitive serodiagnosis of infectious mononucleosis (IM) caused by EBV. The most useful markers in sera from such patients proved to be IgM antibodies against p54, p138, and p150. Additional positive markers for recent or ongoing IM apparently were IgG antibodies against p54 and p138. In contrast, anti-p72 IgG had a high preference for sera from healthy blood donors and, therefore, can be considered indicative of past exposure to the virus. Altogether, the individual ELISAs proved to be as specific and at least as sensitive for the diagnosis of IM as the currently available standard techniques are. Moreover, our findings suggest that, by combining individual test antigens, a workable ELISA system consisting of three assays (IgM against p54, p138, and p150; IgG against p54 and p138; and IgG against p72) can be established for the standardized rapid diagnosis of acute EBV infections. PMID:2172287

Development of a Molecularly Imprinted Polymer-Based Sensor for the Electrochemical Determination of Triacetone Triperoxide (TATP)

PubMed Central

Mamo, Samuel Kassahun; Gonzalez-Rodriguez, Jose

2014-01-01

The explosive triacetone triperoxide (TATP), which can be prepared from commercially readily available reagents following an easy synthetic procedure, is one of the most common components of improvised explosive devices (IEDs). Molecularly-imprinted polymer (MIP) electrochemical sensors have proved useful for the determination of different compounds in different matrices with the required sensitivity and selectivity. In this work, a highly sensitive and selective molecularly imprinted polymer with electrochemical capabilities for the determination of TATP has been developed. The molecular imprinting has been performed via electropolymerisation onto a glassy carbon electrode surface by cyclic voltammetry from a solution of pyrrole functional monomer, TATP template and LiClO4. Differential Pulse Voltammetry of TATP, with LiClO4 as supporting electrolyte, was performed in a potential range of −2.0 V to +1.0 V (vs. Ag/AgCl). Three-factor two-level factorial design was used to optimise the monomer concentration at 0.1 mol·L−1, template concentration at 100 mmol·L−1 and the number of cyclic voltammetry scan cycles to 10. The molecularly imprinted polymer-modified glassy carbon electrode demonstrated good performance at low concentrations for a linear range of 82–44,300 μg·L−1 and a correlation coefficient of r2 = 0.996. The limits of detection (LoD) and quantification (LoQ) achieved were 26.9 μg·L−1 and 81.6 μg·L−1, respectively. The sensor demonstrated very good repeatability with precision values (n = 6, expressed as %RSD) of 1.098% and 0.55% for 1108 and 2216 μg·L−1, respectively. It also proved selective for TATP in the presence of other explosive substances such as PETN, RDX, HMX, and TNT. PMID:25490589

High-Resolution Melting-Curve Analysis of obg Gene to Differentiate the Temperature-Sensitive Mycoplasma synoviae Vaccine Strain MS-H from Non-Temperature-Sensitive Strains

PubMed Central

Shahid, Muhammad A.; Markham, Philip F.; Marenda, Marc S.; Agnew-Crumpton, Rebecca; Noormohammadi, Amir H.

2014-01-01

Temperature-sensitive (ts +) vaccine strain MS-H is the only live attenuated M. synoviae vaccine commercially available for use in poultry. With increasing use of this vaccine to control M. synoviae infections, differentiation of MS-H from field M. synoviae strains and from rarely occurring non-temperature-sensitive (ts –) MS-H revertants has become important, especially in countries where local strains are indistinguishable from MS-H by sequence analysis of variable lipoprotein haemagglutinin (vlhA) gene. Single nucleotide polymorphisms (SNPs) in the obg of MS-H have been found to associate with ts phenotype. In this study, four PCRs followed by high-resolution melting (HRM)-curve analysis of the regions encompassing these SNPs were developed and evaluated for their potential to differentiate MS-H from 36 M. synoviae strains/isolates. The nested-obg PCR-HRM differentiated ts + MS-H vaccine not only from field M. synoviae strains/isolates but also from ts – MS-H revertants. The mean genotype confidence percentages, 96.9±3.4 and 8.8±11.2 for ts + and ts – strains, respectively, demonstrated high differentiating power of the nested-obg PCR-HRM. Using a combination of nested-obg and obg-F3R3 PCR-HRM, 97% of the isolates/strains were typed according to their ts phenotype with all MS-H isolates typed as MS-H. A set of respiratory swabs from MS-H vaccinated specific pathogen free chickens and M. synoviae infected commercial chicken flocks were tested using obg PCR-HRM system and results were consistent with those of vlhA genotyping. The PCR-HRM system developed in this study, proved to be a rapid and reliable tool using pure M. synoviae cultures as well as direct clinical specimens. PMID:24643035

Immunohistochemical Markers Distinguishing Cholangiocellular Carcinoma (CCC) from Pancreatic Ductal Adenocarcinoma (PDAC) Discovered by Proteomic Analysis of Microdissected Cells*

PubMed Central

Padden, Juliet; Ahrens, Maike; Kälsch, Julia; Bertram, Stefanie; Megger, Dominik A.; Bracht, Thilo; Eisenacher, Martin; Kocabayoglu, Peri; Meyer, Helmut E.; Sipos, Bence; Baba, Hideo A.; Sitek, Barbara

2016-01-01

Cholangiocellular carcinoma (CCC) and pancreatic ductal adenocarcinoma (PDAC) are two highly aggressive cancer types that arise from epithelial cells of the pancreatobiliary system. Owing to their histological and morphological similarity, differential diagnosis between CCC and metastasis of PDAC located in the liver frequently proves an unsolvable issue for pathologists. The detection of biomarkers with high specificity and sensitivity for the differentiation of these tumor types would therefore be a valuable tool. Here, we address this problem by comparing microdissected CCC and PDAC tumor cells from nine and eleven cancer patients, respectively, in a label-free proteomics approach. The novel biomarker candidates were subsequently verified by immunohistochemical staining of 73 CCC, 78 primary, and 18 metastatic PDAC tissue sections. In the proteome analysis, we found 180 proteins with a significantly differential expression between CCC and PDAC cells (p value < 0.05, absolute fold change > 2). Nine candidate proteins were chosen for an immunohistochemical verification out of which three showed very promising results. These were the annexins ANXA1, ANXA10, and ANXA13. For the correct classification of PDAC, ANXA1 showed a sensitivity of 84% and a specificity of 85% and ANXA10 a sensitivity of 90% at a specificity of 66%. ANXA13 was higher abundant in CCC. It presented a sensitivity of 84% at a specificity of 55%. In metastatic PDAC tissue ANXA1 and ANXA10 showed similar staining behavior as in the primary PDAC tumors (13/18 and 17/18 positive, respectively). ANXA13, however, presented positive staining in eight out of eighteen secondary PDAC tumors and was therefore not suitable for the differentiation of these from CCC. We conclude that ANXA1 and ANXA10 are promising biomarker candidates with high diagnostic values for the differential diagnosis of intrahepatic CCC and metastatic liver tumors deriving from PDAC. PMID:26644413

Immunohistochemical Markers Distinguishing Cholangiocellular Carcinoma (CCC) from Pancreatic Ductal Adenocarcinoma (PDAC) Discovered by Proteomic Analysis of Microdissected Cells.

PubMed

Padden, Juliet; Ahrens, Maike; Kälsch, Julia; Bertram, Stefanie; Megger, Dominik A; Bracht, Thilo; Eisenacher, Martin; Kocabayoglu, Peri; Meyer, Helmut E; Sipos, Bence; Baba, Hideo A; Sitek, Barbara

2016-03-01

Cholangiocellular carcinoma (CCC) and pancreatic ductal adenocarcinoma (PDAC) are two highly aggressive cancer types that arise from epithelial cells of the pancreatobiliary system. Owing to their histological and morphological similarity, differential diagnosis between CCC and metastasis of PDAC located in the liver frequently proves an unsolvable issue for pathologists. The detection of biomarkers with high specificity and sensitivity for the differentiation of these tumor types would therefore be a valuable tool. Here, we address this problem by comparing microdissected CCC and PDAC tumor cells from nine and eleven cancer patients, respectively, in a label-free proteomics approach. The novel biomarker candidates were subsequently verified by immunohistochemical staining of 73 CCC, 78 primary, and 18 metastatic PDAC tissue sections. In the proteome analysis, we found 180 proteins with a significantly differential expression between CCC and PDAC cells (p value < 0.05, absolute fold change > 2). Nine candidate proteins were chosen for an immunohistochemical verification out of which three showed very promising results. These were the annexins ANXA1, ANXA10, and ANXA13. For the correct classification of PDAC, ANXA1 showed a sensitivity of 84% and a specificity of 85% and ANXA10 a sensitivity of 90% at a specificity of 66%. ANXA13 was higher abundant in CCC. It presented a sensitivity of 84% at a specificity of 55%. In metastatic PDAC tissue ANXA1 and ANXA10 showed similar staining behavior as in the primary PDAC tumors (13/18 and 17/18 positive, respectively). ANXA13, however, presented positive staining in eight out of eighteen secondary PDAC tumors and was therefore not suitable for the differentiation of these from CCC. We conclude that ANXA1 and ANXA10 are promising biomarker candidates with high diagnostic values for the differential diagnosis of intrahepatic CCC and metastatic liver tumors deriving from PDAC. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Novel cellulose-based halochromic test strips for naked-eye detection of alkaline vapors and analytes.

PubMed

Abou-Yousef, Hussein; Khattab, Tawfik A; Youssef, Yehia A; Al-Balakocy, Naser; Kamel, Samir

2017-08-01

A simple, portable and highly sensitive naked-eye test strip is successfully prepared for optical detection of gaseous and aqueous alkaline analytes. Novel pH-sensory tricyanofuran-hydrazone (TCFH) disperse colorant containing a hydrazone recognition functional moiety is successfully synthesized via azo-coupling reaction between active methyl-containing tricyanofuran (TCF) heterocycle and diazonium salt of 4-aminobenzaldehyde followed by Knoevenagel condensation with malononitrile. UV-vis absorption spectra display solvatochromism and reversible color changes of the TCFH solution in dimethyl sulfoxide in response to pH variations. We investigate the preparation of hydrophobic cellulose/polyethylene terephthalate composites characterized by their high affinity for disperse dyes. Composite films made from CA, Cell/CA, PET/CA, and Cell/PET-CA are produced via solvent-casting procedure using 10-30% modified cellulose or modified polyethylene terephthalate. The mechanical properties and morphologies of these composite films are investigated. The prepared pH-sensory hydrazone-based disperse dye is then applied to dye the produced cellulose-based composite films employing the high temperature pressure dyeing procedure. The produced halochromic PET-CA-TCFH test strip provide an instant visible signal from orange to purple upon exposure to alkaline conditions as proved by the coloration measurements. The sensor strip exhibits high sensitivity and quick detection toward ammonia in both of aqueous and vapor phases by naked-eye observations at room temperature and atmospheric pressure. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of upper urinary tract tumors by FISH in Chinese patients.

PubMed

Shan, Zhengfei; Wu, Peng; Zheng, Shaobin; Tan, Wanlong; Zhou, Haikuan; Zuo, Yi; Qi, Huan; Zhang, Peng; Peng, Hongmei; Wang, Yanfen

2010-12-01

Upper urinary tract tumor (UUTT) usually presents a high grade and stage, and recurs frequently. The aim of this study was to evaluate the utility of a fluorescence in situ hybridization (FISH) assay on chromosomes 3, 7, 9, and 17 as a reliable and noninvasive method for the diagnosis of Chinese patients with UUTT. Urine specimens from 50 patients with UUTT and 25 donors without evidence of urothelial tumors were analyzed by cytology and FISH. Voided urine samples from 20 normal individuals were used to establish the cut-off values for FISH assay. The McNemar test was applied for sensitivity and specificity. The overall sensitivity of FISH was statistically significantly greater than that of cytology (84.0 vs. 40.0%, P = 0.000). The overall specificities of FISH and urine cytology were all 96.0% (P = 1.000). Polysomy in chromosomes 3, 7, and 17 were 38, 42, and 30%, respectively. Heterozygous and homozygous loss of the p16 locus was found in 36 and 32%, respectively. FISH analysis performed on cells collected from voided urine is feasible, and FISH could prove to be a reliable and less invasive ancillary test and improve the sensitivity of urine cytology in the diagnosis of UUTT. Copyright © 2010 Elsevier Inc. All rights reserved.

High-performance dye-sensitized solar cells based on solvent-free electrolytes produced from eutectic melts.

PubMed

Bai, Yu; Cao, Yiming; Zhang, Jing; Wang, Mingkui; Li, Renzhi; Wang, Peng; Zakeeruddin, Shaik M; Grätzel, Michael

2008-08-01

Low-cost excitonic solar cells based on organic optoelectronic materials are receiving an ever-increasing amount of attention as potential alternatives to traditional inorganic photovoltaic devices. In this rapidly developing field, the dye-sensitized solar cell (DSC) has achieved so far the highest validated efficiency of 11.1% (ref. 2) and remarkable stability. However, the cells with the best performance use volatile solvents in their electrolytes, which may be prohibitive for outdoor solar panels in view of the need for robust encapsulation. Solvent-free room-temperature ionic liquids have been pursued as an attractive solution to this dilemma, and device efficiencies of over 7% were achieved by using some low-viscosity formulations containing 1-ethyl-3-methylimidazolium thiocyanate, selenocyanate, tricyanomethide or tetracyanoborate. Unfortunately, apart from tetracyanoborate, all of these low-viscosity melts proved to be unstable under prolonged thermal stress and light soaking. Here, we introduce the concept of using eutectic melts to produce solvent-free liquid redox electrolytes. Using a ternary melt in conjunction with a nanocrystalline titania film and the amphiphilic heteroleptic ruthenium complex Z907Na (ref. 10) as a sensitizer, we reach excellent stability and an unprecedented efficiency of 8.2% under air-mass 1.5 global illumination. Our results are of importance to realize large-scale outdoor applications of mesoscopic DSCs.

Usefulness and safety of biliary percutaneous transluminal forceps biopsy (PTFB): our experience.

PubMed

Ierardi, Anna Maria; Mangini, Monica; Fontana, Federico; Floridi, Chiara; De Marchi, Giuseppe; Petrillo, Mario; Capasso, Raffaella; Chini, Claudio; Cocozza, Eugenio; Cuffari, Salvatore; Segato, Sergio; Rotondo, Antonio; Carrafiello, Gianpaolo

2014-03-01

To evaluate the usefulness and safety of percutaneous transluminal forceps biopsy in patients suspected of having a malignant biliary obstruction. Forty consecutive patients (21 men and 19 women; mean age, 71.9 years) underwent forceps biopsy through percutaneous transhepatic biliary access performed to drain bile. Lesions involved the common bile duct (n 8), common hepatic duct (n 18), hilum (n 6), ampullary segment of the common bile duct (n 8) and were biopsied with 7-F biopsy forceps. Final diagnosis was confirmed with pathologic findings at surgery, or clinical and radiologic follow-up. Twenty-one of 40 biopsies resulted in correct diagnosis of malignancy. Thirteen biopsy diagnosis were proved to be true-negative. There were six false-negative and no false-positive diagnoses. Sensitivity, specificity and accuracy in aspecific biliary obstructions were 85%, 100% and 88,7% respectively. Sensitivity of biopsy in malignancies was higher than in benign obstructions (100% vs 68,4%, CI = 95%). Sensitivity was lower in the hilum tract and in the common bile duct than in other sites (CI = 95%). No major complications related to biopsy procedures occurred. Percutaneous transluminal forceps biopsy is a safe procedure, easy to perform through a transhepatic biliary drainage tract, providing high accuracy in the diagnosis of malignant biliary obstructions.

Identification and evaluation of cyp1a transcript expression in fish as molecular biomarker for petroleum contamination in tropical fresh water ecosystems.

PubMed

dos Anjos, Nislanha Ana; Schulze, Tobias; Brack, Werner; Val, Adalberto Luis; Schirmer, Kristin; Scholz, Stefan

2011-05-01

In order to monitor potential contamination deriving from exploration and transport of oil in the Urucu region (Brazil), there is a need to establish suitable biomarkers for native Amazonian fish. Therefore, the transcript expression of various potentially sensitive genes (ahr2(1), cyp1a, hmox1, hsp70, maft, mt, nfe212, gstp1 and nqo1) in fish exposed to water soluble fractions of oil (WSF) was compared. The analysis was first performed in an established laboratory model, the zebrafish embryo. The cyp1a gene proved to be the most sensitive and robust marker for oil contamination and, hence, was selected to study the effect of oil-derived contaminants in the Amazonian cichlid Astronotus ocellatus. Induction of cyp1a transcript expression was observed for ≥0.0061% (v/v) WSFs. In liver samples of fish, collected from different lakes in the Urucu oil mining area, no elevated expression of cyp1a transcripts was observed. The data demonstrate the high sensitivity of cyp1a as indicator of oil exposure; further studies should be considered to test its usefulness at known contaminated sites and to evaluate influential factors by, e.g. mesocosm experiments. Copyright © 2011 Elsevier B.V. All rights reserved.

Absolute neutrino mass measurements

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wolf, Joachim

2011-10-06

The neutrino mass plays an important role in particle physics, astrophysics and cosmology. In recent years the detection of neutrino flavour oscillations proved that neutrinos carry mass. However, oscillation experiments are only sensitive to the mass-squared difference of the mass eigenvalues. In contrast to cosmological observations and neutrino-less double beta decay (0v2{beta}) searches, single {beta}-decay experiments provide a direct, model-independent way to determine the absolute neutrino mass by measuring the energy spectrum of decay electrons at the endpoint region with high accuracy.Currently the best kinematic upper limits on the neutrino mass of 2.2eV have been set by two experiments inmore » Mainz and Troitsk, using tritium as beta emitter. The next generation tritium {beta}-experiment KATRIN is currently under construction in Karlsruhe/Germany by an international collaboration. KATRIN intends to improve the sensitivity by one order of magnitude to 0.2eV. The investigation of a second isotope ({sup 137}Rh) is being pursued by the international MARE collaboration using micro-calorimeters to measure the beta spectrum. The technology needed to reach 0.2eV sensitivity is still in the R and D phase. This paper reviews the present status of neutrino-mass measurements with cosmological data, 0v2{beta} decay and single {beta}-decay.« less

Radiation Measurement Systems and Experiences in Japan after the Fukushima Accident

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

In the approximately 4 years since the March 2011 earthquake and subsequent Tsunami damaged the three Dai-Ichi nuclear power plants, the AREVA and Canberra team have deployed a variety of different radiation measurement machines in Japan. These measurement projects or instruments include: - Dose-rate mapping of the close-in areas on the damaged reactor site using the stored output of dose rate meters carried by workers planning for the installing of a water processing unit; - Spectroscopic on-line measurements of the first water processing unit on the site, where these nuclide-specific measurements at multiple points allowed remote users to determine themore » optimum processing parameters - General purpose food measurement units, both high precision HPGe systems and low cost NaI systems, which were used throughout the country for food quality measurements; - In-vivo measurement systems, both fixed and mobile whole body counting units, that were used on at least 500,000 people, demonstrating to them that internal doses were very low; - In-vivo measurements with special high-sensitivity whole body counters on babies and children, demonstrating to the parents of these children that internal doses are very low; - Automatic systems for high throughput assay of bags of rice that are part of the consumer confidence plan to prove to customers that Fukushima Prefecture rice is safe; - High sensitivity automatic system to assay boxes of special semi-dry persimmons and to report the activity of each individual item within the box meets the regulatory limit; - System to assay soil on a conveyor belt and sort the output according to level of radioactivity, which would then reduce the volume of material that must be treated as radioactive; - System to assay a truck loaded with 1 cubic meter sacks of soil and vegetation, and report the results of each individual sack. - On-line water measurement system for SrY90 at levels that are suitable for release to the environment; - Mobile system to prove that rolls of grass harvested for animal feed meet the regulatory requirements. This document briefly describes the purpose of each measurement project, describes the instruments and assay method that used, and discusses some of the operational experiences from each of these projects. (authors)« less

Video-game epilepsy: a European study.

PubMed

Kasteleijn-Nolst Trenité, D G; da Silva, A M; Ricci, S; Binnie, C D; Rubboli, G; Tassinari, C A; Segers, J P

1999-01-01

With the introduction of Nintendo video-games on a large scale, reports of children having seizures while playing suggested a possible specific, provocative factor. Although 50% of the photosensitive patients are also sensitive to a 50-Hz television, nonphotosensitive patients with a history of video-game seizures were described as well. The question arises whether this is a mere coincidence, provoked by fatigue and stress, is related to the reaction to the television screen itself, or depends on the movement and color of the pictures of this specific game. A European study was performed in four countries and five sites. All patients were selected because of a history of television, video- or computer-game seizures, with a history of sun-light-, discotheque-, or black and white pattern-evoked seizures, or were already known to be sensitive to intermittent photic stimulation. A total of 387 patients were investigated; 220 (75%) were female and 214 (55%) of those were < 18 years of age. After a routine examination, intermittent photic, pattern, and television stimulation were performed in a standardized way. The patients were investigated with Super Mario World and a standard relatively nonprovocative TV program, both on a 50- and 100-Hz television. Regardless of the distance, Super Mario World proved to be more provocative than the standard program (Wilcoxon, p < 0.05). Eighty-five percent showed epileptiform discharges evoked by intermittent photic stimulation. Forty-five percent of patients were 50-Hz television sensitive and 26% were 100-Hz television sensitive. Pattern sensitivity was found in 28% of patients. The patients, referred because of a television, video- or computer-game seizure, were significantly more sensitive to pattern and to the 50-Hz television (chi square, p < 0.001). More patients are sensitive when playing Super Mario, compared with the standard program (Wilcoxon, p = 0.001) and more sensitive with playing versus viewing (p = 0.016). Of the patients who were referred because of seizures in front of the television, or evoked by a video- or computer game, 14% proved not to be photosensitive. Although no difference in age or use of medication was found, twice as many men were found in this nonphotosensitive group.

A new D-dimer cutoff in bedridden hospitalized elderly patients.

PubMed

Granziera, Serena; Rechichi, Alfonsina; De Rui, Marina; De Carlo, Paola; Bertozzo, Giulia; Marigo, Lucia; Nante, Giovanni; Manzato, Enzo

2013-03-01

Asymptomatic deep vein thrombosis (DVT) and pulmonary embolism are leading causes of morbidity following the hospitalization of elderly people. The diagnosis of DVT is supported by the D-dimer laboratory assay. The concentration of D-dimer increases in patients with DVT, but may be high in other conditions too (i.e. cancer, infections and inflammation). Old age coincides with a physiological increase in D-dimer values, and that is why D-dimer assay in the elderly is characteristically highly sensitive but scarcely specific. The aim of our study was to explore the reliability of different D-dimer cutoffs for the diagnosis of asymptomatic DVT in a population of bedridden hospitalized elderly patients. We studied 199 patients who were a mean 86.3 ± 6.7 years old. All participants underwent lower limb Doppler ultrasound (DUS) and D-dimer venous blood sampling on admission. In our cohort, the usual cutoff proved highly sensitive (100%), but its specificity was very poor (20.1%). To find a higher cutoff that could improve the method's specificity, we analyzed our data using a receiver operating characteristic curve analysis. The resulting D-dimer cutoff of 492 μg/l enabled us to retain the same sensitivity while improving the test's specificity to 39.1%, with a consequent improvement in its positive predictive value and accuracy. In addition to improving the method's reliability, this result may be helpful in clinical practice, in both medical wards and nursing homes. By adopting a cutoff of 492 μg/l, clinicians could significantly increase the proportion of older patients in whom DVT can be safely ruled out, reducing referrals for DUS and administration of heparin, with consequent clinical, practical and economic advantages.

ICan: An Optimized Ion-Current-Based Quantification Procedure with Enhanced Quantitative Accuracy and Sensitivity in Biomarker Discovery

PubMed Central

2015-01-01

The rapidly expanding availability of high-resolution mass spectrometry has substantially enhanced the ion-current-based relative quantification techniques. Despite the increasing interest in ion-current-based methods, quantitative sensitivity, accuracy, and false discovery rate remain the major concerns; consequently, comprehensive evaluation and development in these regards are urgently needed. Here we describe an integrated, new procedure for data normalization and protein ratio estimation, termed ICan, for improved ion-current-based analysis of data generated by high-resolution mass spectrometry (MS). ICan achieved significantly better accuracy and precision, and lower false-positive rate for discovering altered proteins, over current popular pipelines. A spiked-in experiment was used to evaluate the performance of ICan to detect small changes. In this study E. coli extracts were spiked with moderate-abundance proteins from human plasma (MAP, enriched by IgY14-SuperMix procedure) at two different levels to set a small change of 1.5-fold. Forty-five (92%, with an average ratio of 1.71 ± 0.13) of 49 identified MAP protein (i.e., the true positives) and none of the reference proteins (1.0-fold) were determined as significantly altered proteins, with cutoff thresholds of ≥1.3-fold change and p ≤ 0.05. This is the first study to evaluate and prove competitive performance of the ion-current-based approach for assigning significance to proteins with small changes. By comparison, other methods showed remarkably inferior performance. ICan can be broadly applicable to reliable and sensitive proteomic survey of multiple biological samples with the use of high-resolution MS. Moreover, many key features evaluated and optimized here such as normalization, protein ratio determination, and statistical analyses are also valuable for data analysis by isotope-labeling methods. PMID:25285707

Influence of petroleum hydrocarbon contamination on microalgae and microbial activities in a long-term contaminated soil.

PubMed

Megharaj, M; Singleton, I; McClure, N C; Naidu, R

2000-05-01

Petroleum hydrocarbons are widespread environmental pollutants. Although biodegradation of petroleum hydrocarbons has been the subject of numerous investigations, information on their toxicity to microorganisms in soil is limited, with virtually no work conducted on soil algae. We carried out a screening experiment for total petroleum hydrocarbons (TPH) and their toxicity to soil algal populations, microbial biomass, and soil enzymes (dehydrogenase and urease) in a long-term TPH-polluted site with reference to an adjacent unpolluted site. Microbial biomass, soil enzyme activity, and microalgae declined in medium to high-level (5,200-21,430 mg kg(-1) soil) TPH-polluted soils, whereas low-level (<2,120 mg kg(-1) soil) pollution stimulated the algal populations and showed no effect on microbial biomass and enzymes. However, inhibition of all the tested parameters was more severe in soil considered to have medium-level pollution than in soils that were highly polluted. This result could not be explained by chemical analysis alone. Of particular interest was an observed shift in the species composition of algae in polluted soils with elimination of sensitive species in the medium to high polluted soils. Also, an algal growth inhibition test carried out using aqueous eluates prepared from polluted soils supported these results. Given the sensitivity of algae to synthetic pollutants, alteration in the algal species composition can serve as a useful bioindicator of pollution. The results of this experiment suggest that chemical analysis alone is not adequate for toxicological estimations and should be used in conjunction with bioassays. Furthermore, changes in species composition of algae proved to be more sensitive than microbial biomass and soil enzyme activity measurements.

High-affinity nitrate/nitrite transporters NrtA and NrtB of Aspergillus nidulans exhibit high specificity and different inhibitor sensitivity

PubMed Central

Akhtar, Naureen; Karabika, Eugenia; Kinghorn, James R.; Glass, Anthony D.M.; Unkles, Shiela E.

2015-01-01

The NrtA and NrtB nitrate transporters are paralogous members of the major facilitator superfamily in Aspergillus nidulans. The availability of loss-of-function mutations allowed individual investigation of the specificity and inhibitor sensitivity of both NrtA and NrtB. In this study, growth response tests were carried out at a growth-limiting concentration of nitrate (1 mM) as the sole nitrogen source, in the presence of a number of potential nitrate analogues at various concentrations, to evaluate their effect on nitrate transport. Both chlorate and chlorite inhibited fungal growth, with chlorite exerting the greater inhibition. The main transporter of nitrate, NrtA, proved to be more sensitive to chlorate than the minor transporter, NrtB. Similarly, the cation caesium was shown to exert differential effects, strongly inhibiting the activity of NrtB, but not NrtA. In contrast, no inhibition of nitrate uptake by NrtA or NrtB transporters was observed in either growth tests or uptake assays in the presence of bicarbonate, formate, malonate or oxalate (sulphite could not be tested in uptake assays owing to its reaction with nitrate), indicating significant specificity of nitrate transport. Kinetic analyses of nitrate uptake revealed that both chlorate and chlorite inhibited NrtA competitively, while these same inhibitors inhibited NrtB in a non-competitive fashion. The caesium ion appeared to inhibit NrtA in a non-competitive fashion, while NrtB was inhibited uncompetitively. The results provide further evidence of the distinctly different characteristics as well as the high specificity of nitrate uptake by these two transporters. PMID:25855763

An experimental study to evaluate the technological limitations in the understanding of the haemodynamic change in pre-eclampsia.

PubMed

Sengupta

1998-08-01

BACKGROUND: Conventional indices could not define the pathogenesis of pre-eclampsia and its predictability. It has also not been possible to record these indices from the local uteroplacental system where the pathology lies. OBJECTIVE: To investigate the limitations of the currently available blood pressure-flow measuring indices and techniques commonly used in pregnancy.METHOD: Blood pressure and velocity profiles were obtained under various pathophysiological conditions for pregnant and non-pregnant animals and human subjects. The data were analysed using both conventional and computer-based spectral methods. RESULTS: Continuous monitoring of blood pressure and velocity together with their spectral analysis appeared to be a useful sensitive indicator in pregnancy beyond the commonly available conventional analytical method. In high-resistance flow such as in hypertension and in pre-eclampsia, the power amplitude was relatively low at low frequency. Power amplitude remained high at low frequency in normal low-resistance state of pregnancy. CONCLUSION: The results suggest the need to develop a highly sensitive instrumentation whereby any minute variation in mean arterial pressure that is of clinical significance can be measured. Alternatively, analytical advancement, such as use of power spectrum analysers, might prove to be useful and sensitive. Variability of heart rate is an important determinant of the underlying pathophysiology in pregnancy. It is concluded that the heart rate of pre-eclamptics and hypertensives has to increase in order to maintain a constant organic blood flow whereas in normal pregnancy bloow flow can rise even without an incrase in heart rate. Future research should be directed towards blood flow mapping, power spectral analysis and image processing of the blood pressure-flow profile obtained from local and systemic compartments under different pathophysiological conditions of pregnancy.

Electrochemically reduced graphene oxide-modified screen-printed carbon electrodes for a simple and highly sensitive electrochemical detection of synthetic colorants in beverages.

PubMed

Jampasa, Sakda; Siangproh, Weena; Duangmal, Kiattisak; Chailapakul, Orawon

2016-11-01

A simple and highly sensitive electrochemical sensor based on an electrochemically reduced graphene oxide-modified screen-printed carbon electrode (ERGO-SPCE) for the simultaneous determination of sunset yellow (SY) and tartrazine (TZ) was proposed. An ERGO film was coated onto the electrode surface using a cyclic voltammetric method and then characterized by scanning electron microscopy (SEM). In 0.1M phosphate buffer at a pH of 6, the two oxidation peaks of SY and TZ appeared separately at 0.41 and 0.70V, respectively. Surprisingly, the electrochemical response remarkably increased approximately 90- and 20-fold for SY and TZ, respectively, using the modified electrode in comparison to the unmodified electrode. The calibration curves exhibited linear ranges from 0.01 to 20.0µM for SY and from 0.02 to 20.0µM for TZ. The limits of detection were found to be 0.50 and 4.50nM (at S/N=3) for SY and TZ, respectively. Furthermore, this detection platform provided very high selectivity for the measurement of both colorants. This electrochemical sensor was successfully applied to determine the amount of SY and TZ in commercial beverages. Comparison of the results obtained from this proposed method to those obtained by an in-house standard technique proved that this developed method has good agreement in terms of accuracy for practical applications. This sensor offers an inexpensive, rapid and sensitive determination. The proposed system is therefore suitable for routine analysis and should be an alternative method for the analysis of food colorants. Copyright © 2016 Elsevier B.V. All rights reserved.

A sensitive high-performance liquid chromatographic method for the determination of 6-mercaptopurine in plasma using precolumn derivatization and fluorescence detection.

PubMed

Warren, D J; Slørdal, L

1993-02-01

A sensitive high-performance liquid chromatographic (HPLC) method for measuring plasma concentrations of 6-mercaptopurine (6-MP) is described. After protein precipitation with 5-sulfosalicylic acid, samples are subjected to precolumn derivatization using the thiol-reactive fluorophore monobromobimane (mBrB). The drug-mBrB adduct is then resolved by isocratic elution from a C18 reversed-phase support and quantified by fluorescence detection. Recovery of 6-MP after protein precipitation was consistently > 85% and the drug-mBrB adduct was found to be stable for at least 2 weeks at room temperature. With plasma samples containing 30 nM 6-MP, the assay displayed within-run (n = 6) and between-day (n = 6) coefficients of variation of 2.2 and 10.6%, respectively. The limit of detection for 6-MP in plasma was 3 nM (500 pg/ml) and the standard curve was linear up to 3 microM. Using this method, we have observed that 6-MP is stable in heparinized whole blood for at least 24 h provided samples are maintained on ice. Since this method requires few manipulations during sample preparation and is readily adaptable to automated techniques, it may prove useful in the routine clinical laboratory setting.

Development and validation of a method for purification of mallein for the diagnosis of glanders in equines

PubMed Central

2012-01-01

Background The allergic test of mallein is one of the most frequently used tests, together with the Complement Fixation Test (CFT), for the diagnosis of glanders in endemic areas. Mallein, a purified protein derivative (PPD), is produced similarly to PPD tuberculin and the end product is a primarily proteic antigen, which is only poorly purified. The immuno-allergic activity of mallein is believed to be due to a high molecular weight group of proteins present in the antigen. To improve the quality of the antigen, in terms of sensitivity and specificity, a new method of mallein production was developed, in which purification was accomplished by ultrafiltration in a Tangential Flow Filtration system (TFF). Results The TFF methodology efficiently separated the high and low molecular weight protein groups of mallein. The five TFF-purified malleins, produced from Burkholderia mallei strains isolated from clinical cases of glanders in Brazil, proved to be more potent than standard mallein in the induction of an allergic reaction in sensitized animals. Regarding specificity, two of the purified malleins were equivalent to the standard and three were less specific. Conclusion Some of the TFF-purified malleins showed considerable potential to be used as an auxiliary test in the diagnosis of glanders. PMID:22937975

Synergy of climate change and local pressures on saltwater intrusion in heterogeneous coastal aquifers

NASA Astrophysics Data System (ADS)

Abou Najm, M.; Safi, A.; El-Fadel, M.; Doummar, J.; Alameddine, I.

2016-12-01

The relative importance of climate change induced sea level rise on the salinization of a highly urbanized karstified coastal aquifers were compared with non-sustainable pumping. A 3D variable-density groundwater flow and solute transport model was used to predict the displacement of the saltwater-freshwater interface in a pilot aquifer located along the Eastern Mediterranean. The results showed that the influence of sea level rise was marginal when compared with the encroachment of salinity associated with anthropogenic abstraction. Model predictions of salinity mass and volumetric displacement of the interface corresponding to a long-term monthly transient model showed that the saltwater intrusion dynamic is highly sensitive to change in the abstraction rates which were estimated based on combinations of water consumption rates and population growth rates. Salinity encroachment, however, appeared to be more sensitive to water consumption rates in comparison to population growth rates, where a 50% increase in the rate of former led to four times more intrusion as compared to an equivalent increase in population growth rate over 20 years. Coupling both increase in population growth and increased consumption rates had a synergistic effect that aggravated the intrusion beyond the sum of the individual impacts. Adaptation strategies targeting a decrease in groundwater exploitation proved to be effective in retarding the intrusion.

A highly sensitive quantitative cytosensor technique for the identification of receptor ligands in tissue extracts.

PubMed

Lenkei, Z; Beaudet, A; Chartrel, N; De Mota, N; Irinopoulou, T; Braun, B; Vaudry, H; Llorens-Cortes, C

2000-11-01

Because G-protein-coupled receptors (GPCRs) constitute excellent putative therapeutic targets, functional characterization of orphan GPCRs through identification of their endogenous ligands has great potential for drug discovery. We propose here a novel single cell-based assay for identification of these ligands. This assay involves (a) fluorescent tagging of the GPCR, (b) expression of the tagged receptor in a heterologous expression system, (c) incubation of the transfected cells with fractions purified from tissue extracts, and (d) imaging of ligand-induced receptor internalization by confocal microscopy coupled to digital image quantification. We tested this approach in CHO cells stably expressing the NT1 neurotensin receptor fused to EGFP (enhanced green fluorescent protein), in which neurotensin promoted internalization of the NT1-EGFP receptor in a dose-dependent fashion (EC(50) = 0.98 nM). Similarly, four of 120 consecutive reversed-phase HPLC fractions of frog brain extracts promoted internalization of the NT1-EGFP receptor. The same four fractions selectively contained neurotensin, an endogenous ligand of the NT1 receptor, as detected by radioimmunoassay and inositol phosphate production. The present internalization assay provides a highly specific quantitative cytosensor technique with sensitivity in the nanomolar range that should prove useful for the identification of putative natural and synthetic ligands for GPCRs.

Development and validation of a method for purification of mallein for the diagnosis of glanders in equines.

PubMed

de Carvalho Filho, Maurício Baltazar; Ramos, Rodrigo Mauro; Fonseca, Antônio Augusto; de Lima Orzil, Lívia; Sales, Mariana Lázaro; de Assis Santana, Vania Lucia; de Souza, Marcilia Maria Alves; Dos Reis Machado, Evandro; Filho, Paulo Rodrigues Lopes; Leite, Rômulo Cerqueira; Dos Reis, Jenner Karlisson Pimenta

2012-09-02

The allergic test of mallein is one of the most frequently used tests, together with the Complement Fixation Test (CFT), for the diagnosis of glanders in endemic areas. Mallein, a purified protein derivative (PPD), is produced similarly to PPD tuberculin and the end product is a primarily proteic antigen, which is only poorly purified. The immuno-allergic activity of mallein is believed to be due to a high molecular weight group of proteins present in the antigen. To improve the quality of the antigen, in terms of sensitivity and specificity, a new method of mallein production was developed, in which purification was accomplished by ultrafiltration in a Tangential Flow Filtration system (TFF). The TFF methodology efficiently separated the high and low molecular weight protein groups of mallein. The five TFF-purified malleins, produced from Burkholderia mallei strains isolated from clinical cases of glanders in Brazil, proved to be more potent than standard mallein in the induction of an allergic reaction in sensitized animals. Regarding specificity, two of the purified malleins were equivalent to the standard and three were less specific. Some of the TFF-purified malleins showed considerable potential to be used as an auxiliary test in the diagnosis of glanders.

Synthesis of thermo-responsive bovine hemoglobin imprinted nanoparticles by combining ionic liquid immobilization with aqueous precipitation polymerization.

PubMed

Wang, Yongmei; Yang, Chongchong; Sun, Yan; Qiu, Fengtao; Xiang, Yang; Fu, Guoqi

2018-02-01

Surface molecular imprinting over functionalized nanoparticles has proved to be an effective approach for construction of artificial nanomaterials for protein recognition. Herein, we report a strategy for synthesis of core-shell protein-imprinted nanoparticles by the functionalization of nano-cores with ionic liquids followed by aqueous precipitation polymerization to build thermo-responsive imprinted polymer nano-shells. The immobilized ionic liquids can form multiple interactions with the protein template. The polymerization process can produce thermo-reversible physical crosslinks, which are advantageous to enhancing imprinting and facilitating template removal. With bovine hemoglobin as a model template, the imprinted nanoparticles showed temperature-sensitivity in both dispersion behaviors and rebinding capacities. Compared with the ionic-liquid-modified core nanoparticles, the imprinted particles exhibited greatly increased selectivity and two orders of magnitude higher binding affinity for the template protein. The imprinted nanoparticles achieved relatively high imprinting factor up to 5.0 and specific rebinding capacity of 67.7 mg/g, respectively. These nanoparticles also demonstrated rapid rebinding kinetics and good reproducibility after five cycles of adsorption-regeneration. Therefore, the presented approach may be viable for the fabrication of high-performance protein-imprinted nanoparticles with temperature sensitivity. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A rapid spectrophotometric blood cyanide determination applicable to emergency toxicology.

PubMed

Laforge, M; Buneaux, F; Houeto, P; Bourgeois, F; Bourdon, R; Levillain, P

1994-01-01

Cyanide determination in whole blood can be performed by spectrophotometry after using diffusion coupled with coloration by hydroxocobalamin in a Conway dish. The technique may be accelerated by the use of a heating sheet at 45 degrees C. The method proved to be specific, sensitive, and fast, thus permitting measurements in emergency situations.

Vertically building Zn2SnO4 nanowire arrays on stainless steel mesh toward fabrication of large-area, flexible dye-sensitized solar cells.

PubMed

Li, Zhengdao; Zhou, Yong; Bao, Chunxiong; Xue, Guogang; Zhang, Jiyuan; Liu, Jianguo; Yu, Tao; Zou, Zhigang

2012-06-07

Zn(2)SnO(4) nanowire arrays were for the first time grown onto a stainless steel mesh (SSM) in a binary ethylenediamine (En)/water solvent system using a solvothermal route. The morphology evolution following this reaction was carefully followed to understand the formation mechanism. The SSM-supported Zn(2)SnO(4) nanowire was utilized as a photoanode for fabrication of large-area (10 cm × 5 cm size as a typical sample), flexible dye-sensitized solar cells (DSSCs). The synthesized Zn(2)SnO(4) nanowires exhibit great bendability and flexibility, proving potential advantage over other metal oxide nanowires such as TiO(2), ZnO, and SnO(2) for application in flexible solar cells. Relative to the analogous Zn(2)SnO(4) nanoparticle-based flexible DSSCs, the nanowire geometry proves to enhance solar energy conversion efficiency through enhancement of electron transport. The bendable nature of the DSSCs without obvious degradation of efficiency and facile scale up gives the as-made flexible solar cell device potential for practical application.

Evaluation of ion-implanted-silicon detectors for use in intraoperative positron-sensitive probes.

PubMed

Raylman, R R; Wahl, R L

1996-11-01

The continuing development of probes for use with beta (positron and electron) emitting radionuclides may result in more complete excision of tracer-avid tumors. Perhaps one of the most promising radiopharmaceuticals for this task is 18F-labeled-Fluoro-2-Deoxy-D-Glucose (FDG). This positron-emitting agent has been demonstrated to be avidly and rapidly absorbed by many human cancers. We have investigated the use of ion-implanted-silicon detectors in intraoperative positron-sensitive surgical probes for use with FDG. These detectors possess very high positron detection efficiency, while the efficiency for 511 keV photon detection is low. The spatial resolution, as well as positron and annihilation photon detection sensitivity, of an ion-implanted-silicon detector used with 18F was measured at several energy thresholds. In addition, the ability of the device to detect the presence of relatively small amounts of FDG during surgery was evaluated by simulating a surgical field in which some tumor was left intact following lesion excision. The performance of the ion-implanted-silicon detector was compared to the operating characteristics of a positron-sensitive surgical probe which utilizes plastic scintillator. In all areas of performance the ion-implanted-silicon detector proved superior to the plastic scintillator-based probe. At an energy threshold of 14 keV positron sensitivity measured for the ion-implanted-silicon detector was 101.3 cps/kBq, photon sensitivity was 7.4 cps/kBq. In addition, spatial resolution was found to be relatively unaffected by the presence of distant sources of annihilation photon flux. Finally, the detector was demonstrated to be able to localize small amounts of FDG in a simulated tumor bed; indicating that this device has promise as a probe to aid in FDG-guided surgery.

Failure of enzyme encapsulation to prevent sensitization of workers in the dry bleach industry.

PubMed

Liss, G M; Kominsky, J R; Gallagher, J S; Melius, J; Brooks, S M; Bernstein, I L

1984-03-01

BDE added to dry bleach have been associated with immunologic sensitization and development of clinical allergic disease in detergent workers and occasionally in consumers. However, improved dust control and modification of the manufacturing process through encapsulation of enzyme were believed to have reduced or eliminated these problems. To determine whether or not immunologic sensitization could still develop in the detergent industry, we studied employees of a dry bleach manufacturing plant that incorporated encapsulated BDE into a consumer product. We performed air sampling for enzyme dust and total particulates, administered questionnaires, conducted physical examinations, and spirometry in 13 currently exposed, two previously exposed and nine nonexposed, employees. To assess sensitization status, RAST and ELISA were performed. Air concentrations of enzyme dust ranged from 0.002 to 1.57 micrograms/m3; all of these levels were below the TLV of 3.9 micrograms/m3. Positive BDE-specific RAST results (3.4%, 4.4%, and 8.0% binding) were obtained in three of 12 currently exposed workers. Results of personal breathing-zone air sampling indicated that these workers had high dust-exposure levels. Specificity of RAST was verified by RAST inhibition with BDE. BDE-RAST binding was not significantly elevated in the nonworkers (range: 0.6% to 1.4% binding). Positive results for specific IgG by ELISA were obtained in four of 12 currently exposed and in one of two previously exposed workers but in none of the nonexposed workers. We conclude that immunologic sensitization can develop after occupational exposure to encapsulated BDE in the dry bleach industry. We have not proved, however, that this immunologic reactivity is related to clinical sensitivity.

Optimization of geometric characteristics to improve sensing performance of MEMS piezoresistive strain sensors

NASA Astrophysics Data System (ADS)

Mohammed, Ahmed A. S.; Moussa, Walied A.; Lou, Edmond

2010-01-01

In this paper, the design of MEMS piezoresistive strain sensor is described. ANSYS®, finite element analysis (FEA) software, was used as a tool to model the performance of the silicon-based sensor. The incorporation of stress concentration regions (SCRs), to localize stresses, was explored in detail. This methodology employs the structural design of the sensor silicon carrier. Therefore, the induced strain in the sensing chip yielded stress concentration in the vicinity of the SCRs. Hence, this concept was proved to enhance the sensor sensitivity. Another advantage of the SCRs is to reduce the sensor transverse gauge factor, which offered a great opportunity to develop a MEMS sensor with minimal cross sensitivity. Two basic SCR designs were studied. The depth of the SCRs was also investigated. Moreover, FEA simulation is utilized to investigate the effect of the sensing element depth on the sensor sensitivity. Simulation results showed that the sensor sensitivity is independent of the piezoresistors' depth. The microfabrication process flow was introduced to prototype the different sensor designs. The experiments covered operating temperature range from -50 °C to +50 °C. Finally, packaging scheme and bonding adhesive selection were discussed. The experimental results showed good agreement with the FEA simulation results. The findings of this study confirmed the feasibility of introducing SCRs in the sensor silicon carrier to improve the sensor sensitivity while using relatively high doping levels (5 × 1019 atoms cm-3). The fabricated sensors have a gauge factor about three to four times higher compared to conventional thin-foil strain gauges.

[Quantitative surface analysis of Pt-Co, Cu-Au and Cu-Ag alloy films by XPS and AES].

PubMed

Li, Lian-Zhong; Zhuo, Shang-Jun; Shen, Ru-Xiang; Qian, Rong; Gao, Jie

2013-11-01

In order to improve the quantitative analysis accuracy of AES, We associated XPS with AES and studied the method to reduce the error of AES quantitative analysis, selected Pt-Co, Cu-Au and Cu-Ag binary alloy thin-films as the samples, used XPS to correct AES quantitative analysis results by changing the auger sensitivity factors to make their quantitative analysis results more similar. Then we verified the accuracy of the quantitative analysis of AES when using the revised sensitivity factors by other samples with different composition ratio, and the results showed that the corrected relative sensitivity factors can reduce the error in quantitative analysis of AES to less than 10%. Peak defining is difficult in the form of the integral spectrum of AES analysis since choosing the starting point and ending point when determining the characteristic auger peak intensity area with great uncertainty, and to make analysis easier, we also processed data in the form of the differential spectrum, made quantitative analysis on the basis of peak to peak height instead of peak area, corrected the relative sensitivity factors, and verified the accuracy of quantitative analysis by the other samples with different composition ratio. The result showed that the analytical error in quantitative analysis of AES reduced to less than 9%. It showed that the accuracy of AES quantitative analysis can be highly improved by the way of associating XPS with AES to correct the auger sensitivity factors since the matrix effects are taken into account. Good consistency was presented, proving the feasibility of this method.

Rapid and accurate identification by real-time PCR of biotoxin-producing dinoflagellates from the family gymnodiniaceae.

PubMed

Smith, Kirsty F; de Salas, Miguel; Adamson, Janet; Rhodes, Lesley L

2014-03-07

The identification of toxin-producing dinoflagellates for monitoring programmes and bio-compound discovery requires considerable taxonomic expertise. It can also be difficult to morphologically differentiate toxic and non-toxic species or strains. Various molecular methods have been used for dinoflagellate identification and detection, and this study describes the development of eight real-time polymerase chain reaction (PCR) assays targeting the large subunit ribosomal RNA (LSU rRNA) gene of species from the genera Gymnodinium, Karenia, Karlodinium, and Takayama. Assays proved to be highly specific and sensitive, and the assay for G. catenatum was further developed for quantification in response to a bloom in Manukau Harbour, New Zealand. The assay estimated cell densities from environmental samples as low as 0.07 cells per PCR reaction, which equated to three cells per litre. This assay not only enabled conclusive species identification but also detected the presence of cells below the limit of detection for light microscopy. This study demonstrates the usefulness of real-time PCR as a sensitive and rapid molecular technique for the detection and quantification of micro-algae from environmental samples.

Gluten screening of several dietary supplements by immunochromatographic assay.

PubMed

Oancea, Simona; Wagner, Adriana; Cîrstea, Elena; Sima, Mirela

2011-01-01

Celiac disease (CD) is a chronic intestinal disorder of public health concern caused by gluten ingestion in sensitive individuals. Gluten is a protein found not only in gluten-containing food but also as normal component of drugs and dietary supplements. Detection of gluten in dietary supplements is a very important task required for establishing their gluten status, which is highly important for the safety of products consumed by CD and gluten-sensitive patients. In this paper, we investigated the presence of gluten in twenty one common dietary supplements from the national market using the immunochromatographic assay. This visual assay proved to be an efficient rapid tool for gluten screening as an alternative to the ELISA techniques. The results have shown the presence of gluten in 23.8% of the investigated samples (vitamins, minerals, plant extracts, probiotics supplements, lactoferrin, propolis supplements). The results provide information which may contribute to the completion of the existing lists of gluten-free pharmaceuticals. It is known that for CD patients obtaining accurate information about the gluten content of a particular item is a difficult and time-consuming process.

Aflatoxin B1 Detection Using a Highly-Sensitive Molecularly-Imprinted Electrochemical Sensor Based on an Electropolymerized Metal Organic Framework

PubMed Central

Jiang, Mengjuan; Braiek, Mohamed; Florea, Anca; Chrouda, Amani; Farre, Carole; Bonhomme, Anne; Bessueille, Francois; Vocanson, Francis; Zhang, Aidong; Jaffrezic-Renault, Nicole

2015-01-01

A sensitive electrochemical molecularly-imprinted sensor was developed for the detection of aflatoxin B1 (AFB1), by electropolymerization of p-aminothiophenol-functionalized gold nanoparticles in the presence of AFB1 as a template molecule. The extraction of the template leads to the formation of cavities that are able to specifically recognize and bind AFB1 through π-π interactions between AFB1 molecules and aniline moities. The performance of the developed sensor for the detection of AFB1 was investigated by linear sweep voltammetry using a hexacyanoferrate/hexacyanoferrite solution as a redox probe, the electron transfer rate increasing when the concentration of AFB1 increases, due to a p-doping effect. The molecularly-imprinted sensor exhibits a broad linear range, between 3.2 fM and 3.2 µM, and a quantification limit of 3 fM. Compared to the non-imprinted sensor, the imprinting factor was found to be 10. Selectivity studies were also performed towards the binding of other aflatoxins and ochratoxin A, proving good selectivity. PMID:26371042

A novel feature ranking method for prediction of cancer stages using proteomics data

PubMed Central

Saghapour, Ehsan; Sehhati, Mohammadreza

2017-01-01

Proteomic analysis of cancers' stages has provided new opportunities for the development of novel, highly sensitive diagnostic tools which helps early detection of cancer. This paper introduces a new feature ranking approach called FRMT. FRMT is based on the Technique for Order of Preference by Similarity to Ideal Solution method (TOPSIS) which select the most discriminative proteins from proteomics data for cancer staging. In this approach, outcomes of 10 feature selection techniques were combined by TOPSIS method, to select the final discriminative proteins from seven different proteomic databases of protein expression profiles. In the proposed workflow, feature selection methods and protein expressions have been considered as criteria and alternatives in TOPSIS, respectively. The proposed method is tested on seven various classifier models in a 10-fold cross validation procedure that repeated 30 times on the seven cancer datasets. The obtained results proved the higher stability and superior classification performance of method in comparison with other methods, and it is less sensitive to the applied classifier. Moreover, the final introduced proteins are informative and have the potential for application in the real medical practice. PMID:28934234

Design of SOI wavelength filter based on multiple MMIs structures

NASA Astrophysics Data System (ADS)

Hu, Youfang; Gardes, Frédéric Y.; Jenkins, Richard M.; Finlayson, Ewan D.; Mashanovich, Goran Z.; Reed, Graham T.

2011-01-01

SOI based MMIs prove to be versatile photonic structures for optical power splitting/combining, directional coupling, wavelength multiplexing/demultiplexing, etc. Such a structure benefits from relative ease of fabrication, low sensitivity to fabrication error and low temperature dependence. Whilst the majority of previous designs and optimizations investigated single MMIs, there is significant potential to combine MMIs within a single device for the realization of improved device performance. We have designed and simulated a wavelength filter device consisting of a series of MMIs with different lengths. The bandwidth, free spectral range, and extinction ratio can be controlled by changing the MMI's width and length. We have optimized our design to achieve a -3dB bandwidth of 5nm, a free spectral range of 60nm, an extinction ratio of >30dB, and a side peak suppression ratio of >22dB. Such a device can be used for high performance coarse wavelength filtering. The whole structure can fit into a 70μm×300μm area. Temperature sensitivity of the designed structures was also investigated.

Biotin-streptavidin enzyme-linked immunosorbent assay for detecting Tetrabromobisphenol A in electronic waste.

PubMed

Bu, Dan; Zhuang, Huisheng; Zhou, Xinchu; Yang, Guangxin

2014-03-01

Tetrabromobisphenol A (TBBPA) is a widely used brominated flame retardant. A sensitive and selective indirect competitive biotin-streptavidin-amplified enzyme-linked immunosorbent assay (BA-ELISA) was developed for detecting TBBPA. The optimal hapten of TBBPA was 2-(2,6-dibromo-4-(2-(3,5-dibromo-4-hydroxyphenly)propan-2-yl)) acetic acid. Several physiochemical factors that influence assay performance, such as optimal coupling concentration of immunogen and antibody, organic solvent, ionic strength, and pH, were studied and optimized. The limit of detection (IC10) was 0.027 ng/mL and the median inhibitory concentration (IC50) was 0.58 ng/mL. The BA-ELISA was highly selective, with low cross-reactivity with TBBPA analogs. Finally, the assay was used to detect TBBPA in electronic waste samples. The results are consistent with those using liquid chromatography, which proves that the proposed immunoassay is accurate and receptive. This BA-ELISA method is suitable for the rapid and sensitive screening of TBBPA in environmental monitoring. © 2013 Published by Elsevier B.V.

Development of a polymerase chain reaction assay for the detection of pseudorabies virus in clinical samples

PubMed Central

Pérez, Lester J.; de Arce, Heidy Díaz

2009-01-01

Aujeszky’s disease, also known as pseudorabies causes severe economic losses in swine industry and affects the pig husbandry all over the world. The conventional diagnostic procedure is time-consuming and false-negative results may occur in submissions from latently infected animals. The development, optimization and evaluation of a polymerase chain reaction (PCR) assay are presented for the diagnosis of pseudorabies infection. This assay was based on the amplification of a highly conserved viral gD gene fragment. PCR products of the expected size were obtained from PRV strains. Non-specific reactions were not observed when a related herpesvirus, other porcine DNA genome viruses and uninfected cells were used to assess PCR. The analytical sensitivity of the test was estimated to be 1.34 TCID50/ 50 uL. The analysis of tissue homogenate samples from naturally infected animals proved the potential usefulness of the method for a rapid disease diagnosis from field cases. A rapid, sensitive and specific PCR-based diagnostic assay to detect pseudorabies virus in clinical samples is provided. PMID:24031383

Identification of carbohydrates by matrix-free material-enhanced laser desorption/ionisation mass spectrometry.

PubMed

Hashir, Muhammad Ahsan; Stecher, Guenther; Bakry, Rania; Kasemsook, Saowapak; Blassnig, Bernhard; Feuerstein, Isabel; Abel, Gudrun; Popp, Michael; Bobleter, Ortwin; Bonn, Guenther K

2007-01-01

Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS) is a sensitive mass spectrometric technique which utilises acidic materials as matrices for laser energy absorption, desorption and ionisation of analytes. These matrix materials produce background signals particularly in the low-mass range and make the detection and identification of small molecules difficult and nearly impossible. To overcome this problem this paper introduces matrix-free material-enhanced laser desorption/ionisation mass spectrometry (mf-MELDI-MS) for the screening and analysis of small molecules such as carbohydrates. For this purpose, 4,4'-azo-dianiline was immobilised on silica gel enabling the absorption of laser energy sufficient for successful desorption and ionisation of low molecular weight compounds. The particle and pore sizes, the solvent system for suspension and the sample preparation procedures have been optimised. The newly synthesised MELDI material delivered excellent spectra with regard to signal-to-noise ratio and detection sensitivity. Finally, wheat straw degradation products and Salix alba L. plant extracts were analysed proving the high performance and excellent behaviour of the introduced material. Copyright (c) 2007 John Wiley & Sons, Ltd.

Fabrication of taste sensor for education

NASA Astrophysics Data System (ADS)

Wu, Xiao; Tahara, Yusuke; Toko, Kiyoshi; Kuriyaki, Hisao

2017-03-01

In order to solve the unconcern to usefulness of learning science among high school students in Japan, we developed a simple fabricated taste sensor with sensitivity and selectivity to each taste quality, which can be applied in science class. A commercialized Teflon membrane was used as the polymer membrane holding lipids. In addition, a non-adhesive method is considered to combine the membrane and the sensor electrode using a plastic cap which is easily accessible. The taste sensor for education fabricated in this way showed a good selectivity and sensitivity. By adjusting the composition of trioctylmethylammonium chloride (TOMA) and phosphoric acid di(2-ethylhexyl) ester (PAEE) included in lipid solution, we improved the selectivity of this simple taste sensor to saltiness and sourness. To verify this taste sensor as a useful science teaching material for science class, we applied this taste sensor into a science class for university students. By comparing the results between the sensory test and the sensor response, humans taste showed the same tendency just as the sensor response, which proved the sensor as a useful teaching material for science class.

Molecular diagnosis of strongyloidiasis in a population of an endemic area through nested-PCR.

PubMed

Sharifdini, Meysam; Keyhani, Amir; Eshraghian, Mohammad Reza; Beigom Kia, Eshrat

2018-01-01

This study is aimed to diagnose and analyze strongyloidiasis in a population of an endemic area of Iran using nested-PCR, coupled with parasitological methods. Screening of strongyloidiasis infected people using reliable diagnostic techniques are essential to decrease the mortality and morbidity associated with this infection. Molecular methods have been proved to be highly sensitive and specific for detection of Strongyloides stercoralis in stool samples. A total of 155 fresh single stool samples were randomly collected from residents of north and northwest of Khouzestan Province, Iran. All samples were examined by parasitological methods including formalin-ether concentration and nutrient agar plate culture, and molecular method of nested-PCR. Infections with S. stercoralis were analyzed according to demographic criteria. Based on the results of nested-PCR method 15 cases (9.7%) were strongyloidiasis positive. Nested-PCR was more sensitive than parasitological techniques on single stool sampling. Elderly was the most important population index for higher infectivity with S. stercoralis . In endemic areas of S. stercoralis , old age should be considered as one of the most important risk factors of infection, especially among the immunosuppressed individuals.

An effective established biosensor of bifunctional probes-labeled AuNPs combined with LAMP for detection of fish pathogen Streptococcus iniae.

PubMed

Zhou, Ya; Xiao, Jingfan; Ma, Xin; Wang, Qiyao; Zhang, Yuanxing

2018-06-01

In purpose of valid Streptococcus iniae detection, we established a colorimetric biosensor using gold nanoparticles (AuNPs) labeled with dual functional probes and along with loop-mediated isothermal amplification (LAMP) assay (LAMP-AuNPs). Based on the characteristics of self-aggregation and bio-conjugation with ligands, AuNPs were chosen for observable color change in tandem with LAMP amplification method to reach high sensitivity and easy operation. Meanwhile, the improvement of dual probes that could fully utilize the LAMP product gave the biosensor a stable result exhibition. LAMP-AuNPs targeting gene ftsB, one of the ATP transporter-related genes, turned out favorable specificity in cross reaction among other fish pathogens. The detect limit of 10 2 CFU revealed a better sensitivity compared with polymerase chain reaction (PCR) method and AuNPs lateral flow test strip (LFTS). It was also proved to be effective by zebrafish infection model trials with less than 2-h time consumption and nearly no devices which make it a convenient biosensor for point-to-care S. iniae detection.

Long-term outcome in patients with germ cell tumours treated with POMB/ACE chemotherapy: comparison of commonly used classification systems of good and poor prognosis.

PubMed Central

Hitchins, R. N.; Newlands, E. S.; Smith, D. B.; Begent, R. H.; Rustin, G. J.; Bagshawe, K. D.

1989-01-01

We analysed outcome in 206 consecutive male patients treated for metastatic non-seminomatous germ cell tumour (NSGCT) of testicular or extragonadal origin treated with the POMB/ACE (cisplatin, vincristine, methotrexate, bleomycin, actinomycin D, cyclophosphamide, etoposide) regimen after division into prognostic groups by commonly used clinical classification systems and definitions of adverse prognosis. The adverse prognostic groups of all classification systems and definitions examined showed similar, but only moderate, sensitivity (71-81%) and specificity (52-56%) in predicting death. A simple definition of poor prognosis based on raised initial levels of serum tumour markers alpha fetoprotein (aFP) and human chorionic gonadotrophin (hCG) proved at least as useful (sensitivity 80%, specificity 55%) as other more complicated systems in predicting failure to achieve long-term survival. Comparison of survival between ultra-high dose cisplatin-based combination chemotherapy and patients treated with POMB/ACE shows no advantage from this more toxic approach. This suggests that good results in adverse prognosis patients can be achieved using conventional dose regimens administered intensively. PMID:2467682

Measurement of stable isotopic enrichment and concentration of long-chain fatty acyl-carnitines in tissue by HPLC-MS.

PubMed

Sun, Dayong; Cree, Melanie G; Zhang, Xiao-Jun; Bøersheim, Elisabet; Wolfe, Robert R

2006-02-01

We have developed a new method for the simultaneous measurements of stable isotopic tracer enrichments and concentrations of individual long-chain fatty acyl-carnitines in muscle tissue using ion-pairing high-performance liquid chromatography-electrospray ionization quadrupole mass spectrometry in the selected ion monitoring (SIM) mode. Long-chain fatty acyl-carnitines were extracted from frozen muscle tissue samples by acetonitrile/methanol. Baseline separation was achieved by reverse-phase HPLC in the presence of the volatile ion-pairing reagent heptafluorobutyric acid. The SIM capability of a single quadrupole mass analyzer allows further separation of the ions of interest from the sample matrixes, providing very clean total and selected ion chromatograms that can be used to calculate the stable isotopic tracer enrichment and concentration of long-chain fatty acyl-carnitines in a single analysis. The combination of these two separation techniques greatly simplifies the sample preparation procedure and increases the detection sensitivity. Applying this protocol to biological muscle samples proves it to be a very sensitive, accurate, and precise analytical tool.

Tracking serum antibody response to viral antigens with arrayed imaging reflectometry

NASA Astrophysics Data System (ADS)

Mace, Charles R.; Rose, Robert C.; Miller, Benjamin L.

2009-02-01

Arrayed Imaging Reflectometry, or "AIR", is a new label-free technique for detecting proteins that relies on bindinginduced changes in the response of an antireflective coating on the surface of a silicon ship. Because the technique provides high sensitivity, excellent dynamic range, and readily integrates with standard silicon wafer processing technology, it is an exceptionally attractive platform on which to build systems for detecting proteins in complex solutions. In our early research, we used AIR chips bearing secreted receptor proteins from enteropathogenic E. coli to develop sensors for this pathogen. Recently, we have been exploring an alternative strategy: Rather than detecting the pathogen directly, can one immobilize antigens from a pathogen, and employ AIR to detect antibody responses to those antigens? Such a strategy would provide enhanced sensitivity for pathogen detection (as the immune system essentially amplifies the "signal" caused by the presence of an organism to which it responds), and would also potentially prove useful in the process of vaccine development. We describe herein preliminary results in the application of such a strategy to the detection of antibodies to human papillomavirus (HPV).

Thermo-sensitive and swelling properties of cellouronic acid sodium/poly (acrylamide-co-diallyldimethylammonium chloride) semi-IPN.

PubMed

Zhang, Heng; Gao, Xin; Chen, Keli; Li, Hui; Peng, Lincai

2018-02-01

In current study, cellouronic acid sodium (CAS), obtained from bagasse pith, has been introduced into poly(acrylamide-co-diallyldimethylammonium chloride) (poly(AM-co-DAC)) network to form novel thermo-sensitive semi-IPNs. The structure and morphology of the hydrogels were proved by Fourier transformation infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). The effects of CAS content, initiator charge, cross-linker dosage and swelling-medium property on the thermo-responsive water absorptivity were investigated in detail. The results elucidated that the prepared gels exhibited a thermo-sensibility with an upper critical solution temperature (UCST) and a high water-absorbency. And the values of UCST and equilibrium swelling ratio largely depended on the inner structure of the semi-IPNs and the external solvent property. It was also revealed that the swelling process conformed to the Schott's pseudo second order model and diffusion type was non-Fickian diffusion. The value of activation energy for this polyelectrolyte was found to be 8.74kJ/mol. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pan-arctic trends in terrestrial dissolved organic matter from optical measurements

USGS Publications Warehouse

Mann, Paul J.; Spencer, Robert G.M.; Hernes, Peter J.; Six, Johan; Aiken, George R.; Tank, Suzanne E.; McClelland, James W.; Butler, Kenna D.; Dyda, Rachael Y.; Holmes, Robert M.

2016-01-01

Climate change is causing extensive warming across Arctic regions resulting in permafrost degradation, alterations to regional hydrology and shifting amounts and composition of dissolved organic matter (DOM) transported by streams and rivers. Here, we characterize the DOM composition and optical properties of the six largest Arctic rivers draining into the Arctic Ocean to examine the ability of optical measurements to provide meaningful insights into terrigenous carbon export patterns and biogeochemical cycling. The chemical composition of aquatic DOM varied with season, spring months were typified by highest lignin phenol and dissolved organic carbon (DOC) concentrations with greater hydrophobic acid content, and lower proportions of hydrophilic compounds, relative to summer and winter months. Chromophoric DOM (CDOM) spectral slope (S275–295) tracked seasonal shifts in DOM composition across river basins. Fluorescence and parallel factor analysis identified seven components across the six Arctic rivers. The ratios of “terrestrial humic-like” vs. “marine humic-like” fluorescent components co-varied with lignin monomer ratios over summer and winter months, suggesting fluorescence may provide information on the age and degradation state of riverine DOM. CDOM absorbance (a350) proved a sensitive proxy for lignin phenol concentrations across all six river basins and over the hydrograph, enabling for the first time the development of a single pan-arctic relationship between a350 and terrigenous DOC (R2 = 0.93). Combining this lignin proxy with high-resolution monitoring of a350, pan-arctic estimates of annual lignin flux were calculated to range from 156 to 185 Gg, resulting in shorter and more constrained estimates of terrigenous DOM residence times in the Arctic Ocean (spanning 7 months to 2½ years). Furthermore, multiple linear regression models incorporating both absorbance and fluorescence variables proved capable of explaining much of the variability in lignin composition across rivers and seasons. Our findings suggest that synoptic, high-resolution optical measurements can provide improved understanding of northern high-latitude organic matter cycling and flux, and prove an important technique for capturing future climate-driven changes.

Pan-arctic trends in terrestrial dissolved organic matter from optical measurements

USGS Publications Warehouse

Mann, Paul J.; Spencer, Robert G. M.; Hernes, Peter J.; Six, Johan; Aiken, George R.; Tank, Suzanne E.; McClelland, James W.; Butler, Kenna D.; Dyda, Rachael Y.; Holmes, Robert M.

2016-01-01

Climate change is causing extensive warming across Arctic regions resulting in permafrost degradation, alterations to regional hydrology and shifting amounts and composition of dissolved organic matter (DOM) transported by streams and rivers. Here, we characterize the DOM composition and optical properties of the six largest Arctic rivers draining into the Arctic Ocean to examine the ability of optical measurements to provide meaningful insights into terrigenous carbon export patterns and biogeochemical cycling. The chemical composition of aquatic DOM varied with season, spring months were typified by highest lignin phenol and dissolved organic carbon (DOC) concentrations with greater hydrophobic acid content, and lower proportions of hydrophilic compounds, relative to summer and winter months. Chromophoric DOM (CDOM) spectral slope (S275–295) tracked seasonal shifts in DOM composition across river basins. Fluorescence and parallel factor analysis identified seven components across the six Arctic rivers. The ratios of “terrestrial humic-like” vs. “marine humic-like” fluorescent components co-varied with lignin monomer ratios over summer and winter months, suggesting fluorescence may provide information on the age and degradation state of riverine DOM. CDOM absorbance (a350) proved a sensitive proxy for lignin phenol concentrations across all six river basins and over the hydrograph, enabling for the first time the development of a single pan-arctic relationship between a350 and terrigenous DOC (R2 = 0.93). Combining this lignin proxy with high-resolution monitoring of a350, pan-arctic estimates of annual lignin flux were calculated to range from 156 to 185 Gg, resulting in shorter and more constrained estimates of terrigenous DOM residence times in the Arctic Ocean (spanning 7 months to 2½ years). Furthermore, multiple linear regression models incorporating both absorbance and fluorescence variables proved capable of explaining much of the variability in lignin composition across rivers and seasons. Our findings suggest that synoptic, high-resolution optical measurements can provide improved understanding of northern high-latitude organic matter cycling and flux, and prove an important technique for capturing future climate-driven changes.

Central Sensitization Syndrome and the Initial Evaluation of a Patient with Fibromyalgia: A Review

PubMed Central

Fleming, Kevin C.; Volcheck, Mary M.

2015-01-01

In both primary care and consultative practices, patients presenting with fibromyalgia (FM) often have other medically unexplained somatic symptoms and are ultimately diagnosed as having central sensitization (CS). Central sensitization encompasses many disorders where the central nervous system amplifies sensory input across many organ systems and results in myriad symptoms. A pragmatic approach to evaluate FM and related symptoms, including a focused review of medical records, interviewing techniques, and observations, is offered here, giving valuable tools for identifying and addressing the most relevant symptoms. At the time of the clinical evaluation, early consideration of CS may improve the efficiency of the visit, reduce excessive testing, and help in discerning between typical and atypical cases so as to avoid an inaccurate diagnosis. Discussion of pain and neurophysiology and sensitization often proves helpful. PMID:25973272

Analysis of multiple cell upset sensitivity in bulk CMOS SRAM after neutron irradiation

NASA Astrophysics Data System (ADS)

Pan, Xiaoyu; Guo, Hongxia; Luo, Yinhong; Zhang, Fengqi; Ding, Lili

2018-03-01

In our previous studies, we have proved that neutron irradiation can decrease the single event latch-up (SEL) sensitivity of CMOS SRAM. And one of the key contributions to the multiple cell upset (MCU) is the parasitic bipolar amplification, it bring us to study the impact of neutron irradiation on the SRAM’s MCU sensitivity. After the neutron experiment, we test the devices’ function and electrical parameters. Then, we use the heavy ion fluence to examine the changes on the devices’ MCU sensitivity pre- and post-neutron-irradiation. Unfortunately, neutron irradiation makes the MCU phenomenon worse. Finally, we use the electric static discharge (ESD) testing technology to deduce the experimental results and find that the changes on the WPM region take the lead rather than the changes on the parasitic bipolar amplification for the 90 nm process.

SMOKING INCLINED GROUPS ACCORDING TO THE PHENOTYPE OF THE PTC GENE.

PubMed

Khukhunaishvili, R; Tskvitinidze, S; Koridze, M; Nagervadze, M; Chelidze, N

2016-09-01

The ability to sense phenylthiocarbamide (PTC) bitterness represents a well-known and convenient genetic marker for human populations and biomedical studies. Two basic phenotypes can be dichotomized by PTC sensitivity: PTC-sensitive or "tester" and PTC-insensitive or "non-tester". The majority of the population (approximately 70%) belong to the PTC-sensitive phenotype, while the remaining 30% are PTC-insensitive. The distribution of PTC sensitivities varies by consumption of alcohol, bitter coffee and cigarettes. This study was conducted among randomly selected 90 cigarette smokers living in the Ajara Region of Georgia. Our results indicate that PTC-insensitive phenotypes are correlated with cigarette consumption and should be considered as an important genetic proxy for cigarette use. This marker may prove very useful for identifying adolescents who might benefit from a focused smoking prevention intervention.

Sensitivity improvement of an electrical sensor achieved by control of biomolecules based on the negative dielectrophoretic force.

PubMed

Kim, Hye Jin; Kim, Jinsik; Yoo, Yong Kyoung; Lee, Jeong Hoon; Park, Jung Ho; Hwang, Kyo Seon

2016-11-15

Effective control of nano-scale biomolecules can enhance the sensitivity and limit of detection of an interdigitated microelectrode (IME) sensor. Manipulation of the biomolecules by dielectrophoresis (DEP), especially the negative DEP (nDEP) force, so that they are trapped between electrodes (sensing regions) was predicted to increase the binding efficiency of the antibody and target molecules, leading to a more effective reaction. To prove this concept, amyloid beta 42 (Aβ42) and prostate specific antigen (PSA) protein were respectively trapped between the sensing region owing to the nDEP force under 5V and 0.05V, which was verified with COMSOL simulation. Using the simulation value, the resistance change (ΔR/Rb) of the IME sensor from the specific antibody-antigen reaction of the two biomolecules and the change in fluorescence intensity were compared in the reference (pDEP) and nDEP conditions. The ΔR/Rb value improved by about 2-fold and 1.66-fold with nDEP compared to the reference condition with various protein concentrations, and these increases were confirmed with fluorescence imaging. Overall, nDEP enhanced the detection sensitivity for Aβ42 and PSA by 128% and 258%, respectively, and the limit of detection improved by up to 2-orders of magnitude. These results prove that DEP can improve the biosensor's performance. Copyright © 2016 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Terenziani, Monica; Casalini, Patrizia; Scaperrotta, Gianfranco

Purpose: To assess the occurrence of breast cancer (BC) after exposure to ionizing radiation for pediatric cancer, by means of a multimodal screening program. Patients and Methods: We identified 86 patients who had received chest wall radiation therapy for pediatric cancer. Clinical breast examination (CBE), ultrasound (US), and mammography (MX) were performed yearly. Magnetic resonance imaging (MRI) was added as of October 2007. We calculated the risk of developing BC by radiation therapy dose, patient age, and menarche before or after primary treatment. Results: Eleven women developed a BC from July 2002-February 2010. The sensitivity of the screening methods wasmore » 36% for CBE, 73% for MX, 55% for US, and 100% for MRI; the specificity was 91%, 99%, 95%, and 80% for CBE, MX, US, and MRI, respectively. The annual BC detection rate was 2.9%. The median age at BC diagnosis was 33 years. Although age had no influence, menarche before as opposed to after radiation therapy correlated significantly with BC (P=.027): the annual BC detection rate in the former subgroup was 5.3%. Conclusions: Mammography proved more sensitive and specific in our cohort of young women than CBE or US. Magnetic resonance imaging proved 100% sensitive (but this preliminary finding needs to be confirmed). Our cohort of patients carries a 10-fold BC risk at an age more than 20 years younger than in the general population.« less

High blood Pressure in children and its correlation with three definitions of obesity in childhood

PubMed Central

de Moraes, Leonardo Iezzi; Nicola, Thaís Coutinho; de Jesus, Julyanna Silva Araújo; Alves, Eduardo Roberty Badiani; Giovaninni, Nayara Paula Bernurdes; Marcato, Daniele Gasparini; Sampaio, Jéssica Dutra; Fuly, Jeanne Teixeira Bessa; Costalonga, Everlayny Fiorot

2014-01-01

Background Several authors have correlated the increase of cardiovascular risk with the nutritional status, however there are different criteria for the classification of overweight and obesity in children. Objectives To evaluate the performance of three nutritional classification criteria in children, as definers of the presence of obesity and predictors of high blood pressure in schoolchildren. Methods Eight hundred and seventeen children ranging 6 to 13 years old, enrolled in public schools in the municipality of Vila Velha (ES) were submitted to anthropometric evaluation and blood pressure measurement. The classification of the nutritional status was established by two international criteria (CDC/NCHS 2000 and IOTF 2000) and one Brazilian criterion (Conde e Monteiro 2006). Results The prevalence of overweight was higher when the criterion of Conde e Monteiro (27%) was used, and inferior by the IOTF (15%) criteria. High blood pressure was observed in 7.3% of children. It was identified a strong association between the presence of overweight and the occurrence of high blood pressure, regardless of the test used (p < 0.001). The test showing the highest sensitivity in predicting elevated BP was the Conde e Monteiro (44%), while the highest specificity (94%) and greater overall accuracy (63%), was the CDC criterion. Conclusions The prevalence of overweight in Brazilian children is higher when using the classification criterion of Conde e Monteiro, and lower when the criterion used is IOTF. The Brazilian classification criterion proved to be the most sensitive predictor of high BP risk in this sample. PMID:24676372

Filling the concept with data: integrating data from different in vitro and in silico assays on skin sensitizers to explore the battery approach for animal-free skin sensitization testing.

PubMed

Natsch, Andreas; Emter, Roger; Ellis, Graham

2009-01-01

Tests for skin sensitization are required prior to the market launch of new cosmetic ingredients. Significant efforts are made to replace the current animal tests. It is widely recognized that this cannot be accomplished with a single in vitro test, but that rather the integration of results from different in vitro and in silico assays will be needed for the prediction of the skin sensitization potential of chemicals. This has been proposed as a theoretical scheme so far, but no attempts have been made to use experimental data to prove the validity of this concept. Here we thus try for the first time to fill this widely cited concept with data. To this aim, we integrate and report both novel and literature data on 116 chemicals of known skin sensitization potential on the following parameters: (1) peptide reactivity as a surrogate for protein binding, (2) induction of antioxidant/electrophile responsive element dependent luciferase activity as a cell-based assay; (3) Tissue Metabolism Simulator skin sensitization model in silico prediction; and (4) calculated octanol-water partition coefficient. The results of the in vitro assays were scaled into five classes from 0 to 4 to give an in vitro score and compared to the local lymph node assay (LLNA) data, which were also scaled from 0 to 4 (nonsensitizer/weak/moderate/strong/extreme). Different ways of evaluating these data have been assessed to rate the hazard of chemicals (Cooper statistics) and to also scale their potency. With the optimized model an overall accuracy for predicting sensitizers of 87.9% was obtained. There is a linear correlation between the LLNA score and the in vitro score. However, the correlation needs further improvement as there is still a relatively high variation in the in vitro score between chemicals belonging to the same sensitization potency class.

Analysis of multiple quaternary ammonium compounds in the brain using tandem capillary column separation and high resolution mass spectrometric detection.

PubMed

Falasca, Sara; Petruzziello, Filomena; Kretz, Robert; Rainer, Gregor; Zhang, Xiaozhe

2012-06-08

Endogenous quaternary ammonium compounds are involved in various physiological processes in the central nervous system. In the present study, eleven quaternary ammonium compounds, including acetylcholine, choline, carnitine, acetylcarnitine and seven other acylcarnitines of low polarity, were analyzed from brain extracts using a two dimension capillary liquid chromatography-Fourier transform mass spectrometry method. To deal with their large difference in hydrophobicities, tandem coupling between reversed phase and hydrophilic interaction chromatography columns was used to separate all the targeted quaternary ammonium compounds. Using high accuracy mass spectrometry in selected ion monitoring mode, all the compounds could be detected from each brain sample with high selectivity. The developed method was applied for the relative quantification of these quaternary ammonium compounds in three different brain regions of tree shrews: prefrontal cortex, striatum, and hippocampus. The comparative analysis showed that quaternary ammonium compounds were differentially distributed across the three brain areas. The analytical method proved to be highly sensitive and reliable for simultaneous determination of all the targeted analytes from brain samples. Copyright © 2012 Elsevier B.V. All rights reserved.

Evaluation of the Nurses' Job Satisfaction, and Its Association with Their Moral Sensitivities and Well-being.

PubMed

Jaafarpour, Molouk; Khani, Ali

2012-12-01

Several researchers have described the nurses' work as stressful and that the incidence of the occupational stress-related burnout in the profession was high. The aim of this study was to establish the relationship between the nurses' satisfaction, their psychosocial work environment, the levels of their reported moral sensitivities and their well - being in Iran. This descriptive-correlation study was performed at the ILAM general hospitals, IR, during the year 2011. The research instruments which were used were the Psychosocial Work Environment (PWE), the Moral Sensitivity (MS) and the well-being profile of the nurses. A sample of 120 Registered Nurses (RN) were enrolled in the study by using a simple random sampling method. The descriptive statistics and the Pearson's correlation test were performed by using SPSS. The relationship of the nurses' satisfaction and their psychosocial work environment was moderate (M=106.5, SD= 7.2) . The nurses' moral sensitivity was moderate (M=112.3, SD= 11.2).This study found that there were significant correlations between the PWE factors score and the MS subscale (P< 0.05, p<0.01). In addition, significant correlations were found between the nurses' well-being and the PWE factors (P< 0.05, p<0.01). These findings proved that the nurses perceived their PWE as stressful. The supporting nurses may have a positive effect on their perceptions of well-being. The attending nurses reported less physical symptoms, reduced anxiety and fewer feelings of not being in control.

Anatomisation with slicing: a new privacy preservation approach for multiple sensitive attributes.

PubMed

Susan, V Shyamala; Christopher, T

2016-01-01

An enormous quantity of personal health information is available in recent decades and tampering of any part of this information imposes a great risk to the health care field. Existing anonymization methods are only apt for single sensitive and low dimensional data to keep up with privacy specifically like generalization and bucketization. In this paper, an anonymization technique is proposed that is a combination of the benefits of anatomization, and enhanced slicing approach adhering to the principle of k-anonymity and l-diversity for the purpose of dealing with high dimensional data along with multiple sensitive data. The anatomization approach dissociates the correlation observed between the quasi identifier attributes and sensitive attributes (SA) and yields two separate tables with non-overlapping attributes. In the enhanced slicing algorithm, vertical partitioning does the grouping of the correlated SA in ST together and thereby minimizes the dimensionality by employing the advanced clustering algorithm. In order to get the optimal size of buckets, tuple partitioning is conducted by MFA. The experimental outcomes indicate that the proposed method can preserve privacy of data with numerous SA. The anatomization approach minimizes the loss of information and slicing algorithm helps in the preservation of correlation and utility which in turn results in reducing the data dimensionality and information loss. The advanced clustering algorithms prove its efficiency by minimizing the time and complexity. Furthermore, this work sticks to the principle of k-anonymity, l-diversity and thus avoids privacy threats like membership, identity and attributes disclosure.

CRISPR/Cas9-Mediated Genomic Deletion of the Beta-1, 4 N-acetylgalactosaminyltransferase 1 Gene in Murine P19 Embryonal Carcinoma Cells Results in Low Sensitivity to Botulinum Neurotoxin Type C.

PubMed

Tsukamoto, Kentaro; Ozeki, Chikako; Kohda, Tomoko; Tsuji, Takao

2015-01-01

Botulinum neurotoxins produced by Clostridium botulinum cause flaccid paralysis by inhibiting neurotransmitter release at peripheral nerve terminals. Previously, we found that neurons derived from the murine P19 embryonal carcinoma cell line exhibited high sensitivity to botulinum neurotoxin type C. In order to prove the utility of P19 cells for the study of the intracellular mechanism of botulinum neurotoxins, ganglioside-knockout neurons were generated by deletion of the gene encoding beta-1,4 N-acetylgalactosaminyltransferase 1 in P19 cells using the clustered regularly interspaced short palindromic repeats combined with Cas9 (CRISPR/Cas9) system. By using this system, knockout cells could be generated more easily than with previous methods. The sensitivity of the generated beta-1,4 N-acetylgalactosaminyltransferase 1-depleted P19 neurons to botulinum neurotoxin type C was decreased considerably, and the exogenous addition of the gangliosides GD1a, GD1b, and GT1b restored the susceptibility of P19 cells to botulinum neurotoxin type C. In particular, addition of a mixture of these three ganglioside more effectively recovered the sensitivity of knockout cells compared to independent addition of GD1a, GD1b, or GT1b. Consequently, the genome-edited P19 cells generated by the CRISPR/Cas9 system were useful for identifying and defining the intracellular molecules involved in the toxic action of botulinum neurotoxins.

Recurrent rotator cuff tear: is ultrasound imaging reliable?

PubMed

Gilat, Ron; Atoun, Ehud; Cohen, Ornit; Tsvieli, Oren; Rath, Ehud; Lakstein, Dror; Levy, Ofer

2018-02-02

The diagnostic workup of the painful shoulder after rotator cuff repair (RCR) can be quite challenging. The aim of this study was to assess the reliability of ultrasonography (US) for the detection of recurrent rotator cuff tears in patients with shoulder pain after RCR. We hypothesized that US for the diagnosis of recurrent rotator cuff tear after RCR would not prove to be reliable when compared with surgical arthroscopic confirmation (gold standard). In this cohort study (diagnosis), we retrospectively analyzed the data of 39 patients with shoulder pain after arthroscopic RCR who had subsequently undergone US, followed by revision arthroscopy. The rotator cuff was evaluated first using US for the presence of retears. Thereafter, revision arthroscopy was performed, and the diagnosis was either established or disproved. The sensitivity and specificity of US were assessed in reference to revision arthroscopy (gold standard). A rotator cuff retear was indicated by US in 21 patients (54%) and by revision arthroscopy in 26 patients (67%). US showed a sensitivity of 80.8% and specificity of 100% in the diagnosis of rotator cuff retears. Omission of partial rotator cuff retears resulted in a spike in sensitivity to 94.7%, with 100% specificity remaining. US imaging is a highly sensitive and specific test for the detection of recurrent rotator cuff tears, as confirmed by revision arthroscopy, in patients with a painful shoulder after primary RCR. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Unexpected Rheological Behavior of Hydrophobic Associative Shellac-based Oligomeric Food Thickener.

PubMed

Gao, Jianan; Li, Kun; Xu, Juan; Zhang, Wen-Wen; Ma, Jinju; Liu, Lanxiang; Sun, Yanlin; Zhang, Hong; Li, Kai

2018-06-07

The sodium shellac constituting of "surfactant" monomer, which is sensitive to shear stress, exhibits shear-thickening behavior at low concentration (5 wt%), and reacts with H+ to retain the transient high viscosity under shear, is introduced in this study. The appearance of the sodium shellac with different concentrations in aqueous mode also could be described. The steady-shear flow test proved that under high shear rate, sodium shellac suspension could change from Newtonian fluid to continuous shear thickening of non-Newtonian fluid. Dynamic oscillation test suggested that the sodium shellac solution at low concentration (0.1 and 1 wt%) under low shear rate represented classic viscous fluid behavior (G´´G´), and the solution at high concentration (5, 10 and 15 wt%) represented the classic the elastic gel behavior (G´´G´). Moreover, high shear rate caused a cross-linking point between G´´and G´ curve; at the low concentration, this could be the gel point and at high concentration, it could be attributed to the broken of gel. All of these transforming points were relating to the interaction between the sodium clusters. This interaction should be the hydrophobic association between the particles. In order to prove phenomenon, classic hydrophilic polymer PEO was employed as the disrupting factor to the hydrophobic association. As expected, the shear-thickening behavior vanished after mixing with PEO, which verified our assumption. On the other hand, the high viscosity of the suspension under shear could be retained by reaction with H+ to solidify the transient hydroclusters under shear, meanwhile, sodium shellac had great potential as the functional shear-thickener which could modify the rheological property of the polymer with carboxyl groups, e.g. pectin, alginate or polyacrylic acid. Thus, this natural and green thicker has great potential in food, medical gel, green adhesive, or cosmetic products.

Intensified autophagy compromises the efficacy of radiotherapy against prostate cancer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Koukourakis, Michael I., E-mail: targ@her.forthnet.gr; Kalamida, Dimitra; Mitrakas, Achilleas

2015-05-29

Introduction: Radiotherapy is an equivalent alternative or complement to radical prostatectomy, with high therapeutic efficacy. High risk patients, however, experience high relapse rates, so that research on radio-sensitization is the most evident route to improve curability of this common disease. Materials and methods: In the current study we investigated the autophagic activity in a series of patients with localized prostate tumors treated with radical radiotherapy, using the LC3A and the LAMP2a proteins as markers of autophagosome and lysosome cellular content, respectively. The role of autophagy on prostate cancer cell line resistance to radiation was also examined. Results: Using confocal microscopymore » on tissue biopsies, we showed that prostate cancer cells have, overall, high levels of LC3A and low levels of LAMP2a compared to normal prostate glands. Tumors with a ‘highLC3A/lowLAMP2a’ phenotype, suggestive of intensified lysosomal consumption, had a significantly poorer biochemical relapse free survival. The PC3 radioresistant cell line sustained remarkably its autophagic flux ability after radiation, while the DU145 radiosensitive one experiences a prolonged blockage of the autophagic process. This was assessed with aggresome accumulation detection and LC3A/LAMP2a double immunofluorescence, as well as with sequestrosome/p62 protein detection. By silencing the LC3A or LAMP2a expression, both cell lines became more sensitive to escalated doses of radiation. Conclusions: High base line autophagy activity and cell ability to sustain functional autophagy define resistance of prostate cancer cells to radiotherapy. This can be reversed by blocking up-regulated components of the autophagy pathway, which may prove of importance in the field of clinical radiotherapy. - Highlights: • High LC3A and low LAMP2a levels is a frequent expression pattern of prostate carcinoma. • This pattern of intensified autophagic flux relates with high relapse rates after radiotherapy. • The PC3 radio-resistant cell line sustains remarkably its autophagic flux ability after radiation. • Irradiation of the DU145 radio-sensitive cell line blocks the autophagic flux. • Intense autophagy activity defines prostate cancer radio-resistance, in vivo and in vitro.« less

Design of digital load torque observer in hybrid electric vehicle

NASA Astrophysics Data System (ADS)

Sun, Yukun; Zhang, Haoming; Wang, Yinghai

2008-12-01

In hybrid electric vehicle, engine begain to work only when motor was in high speed in order to decrease tail gas emission. However, permanent magnet motor was sensitive to its load, adding engine to the system always made its speed drop sharply, which caused engine to work in low efficiency again and produced much more environment pollution. Dynamic load torque model of permanent magnet synchronous motor is established on the basic of motor mechanical equation and permanent magnet synchronous motor vector control theory, Full- digital load torque observer and compensation control system is made based on TMS320F2407A. Experiment results prove load torque observer and compensation control system can detect and compensate torque disturbing effectively, which can solve load torque disturbing and decrease gas pollution of hybrid electric vehicle.

Glutathione-Capped Gold Nanoparticles-Based Photoacoustic Sensor for Label-Free Detection of Lead Ions

NASA Astrophysics Data System (ADS)

Shi, R.; Liu, X.-J.; Ying, Y.

2017-07-01

The photoacoustic signal generated by laser-induced nanobubbles (PA-LINB) proved to be a sensitive tool to monitor the aggregation of gold nanoparticles. Here, a simple and label-free photoacoustic method for the rapid detection of Pb2+ in the aqueous phase was developed. Due to the high affinity of Pb2+ ions to glutathione, the presence of Pb2+ led to the aggregation of glutathione-conjugated gold nanoparticles (GSH-GNPs). Hence, by measuring the variation of the PA-LINB signal after the aggregation of GSH-GNPs, Pb2+ can be quantified. A low detection limit for Pb2+ (42 nM) and a wide linear working range ( 42-1000 nM) were achieved. Furthermore, the proposed method showed good selectivity against other metal ions.

Indirect micro-immunofluorescence test for detecting type-specific antibodies to herpes simplex virus.

PubMed

Forsey, T; Darougar, S

1980-02-01

A rapid indirect micro-immunofluorescence test capable of detecting and differentiating type-specific antibodies to herpes simplex virus is described. The test proved highly sensitive and, in 80 patients with active herpes ocular infection, antibody was detected in 94%. No anti-herpes antibody was detected in a control group of 20 patients with adenovirus infections. Testing of animal sera prepared against herpes simplex virus types 1 and 2 and of human sera from cases of ocular and genital herpes infections showed that the test can differentiate antibodies to the infecting serotypes. Specimens of whole blood, taken by fingerprick, and eye secretions, both collected on cellulose sponges, could be tested by indirect micro-immunofluorescence. Anti-herpes IgG, IgM, and IgA can also be detected.

Sinus venosus atrial septal defect as a cause of palpitations and dyspnea in an adult: a diagnostic imaging challenge.

PubMed

Donovan, Michael S; Kassop, David; Liotta, Robert A; Hulten, Edward A

2015-01-01

Sinus venosus atrial septal defects (SV-ASD) have nonspecific clinical presentations and represent a diagnostic imaging challenge. Transthoracic echocardiography (TTE) remains the initial diagnostic imaging modality. However, detection rates have been as low as 12%. Transesophageal echocardiography (TEE) improves diagnostic accuracy though it may not detect commonly associated partial anomalous pulmonary venous return (PAPVR). Cardiac magnetic resonance (CMR) imaging provides a noninvasive, highly sensitive and specific imaging modality of SV-ASD. We describe a case of an adult male with exercise-induced, paroxysmal supraventricular tachycardia who presented with palpitations and dyspnea. Despite nondiagnostic imaging results on TTE, CMR proved to be instrumental in visualizing a hemodynamically significant SV-ASD with PAPVR that ultimately led to surgical correction.

Sinus Venosus Atrial Septal Defect as a Cause of Palpitations and Dyspnea in an Adult: A Diagnostic Imaging Challenge

PubMed Central

Donovan, Michael S.; Kassop, David; Liotta, Robert A.; Hulten, Edward A.

2015-01-01

Sinus venosus atrial septal defects (SV-ASD) have nonspecific clinical presentations and represent a diagnostic imaging challenge. Transthoracic echocardiography (TTE) remains the initial diagnostic imaging modality. However, detection rates have been as low as 12%. Transesophageal echocardiography (TEE) improves diagnostic accuracy though it may not detect commonly associated partial anomalous pulmonary venous return (PAPVR). Cardiac magnetic resonance (CMR) imaging provides a noninvasive, highly sensitive and specific imaging modality of SV-ASD. We describe a case of an adult male with exercise-induced, paroxysmal supraventricular tachycardia who presented with palpitations and dyspnea. Despite nondiagnostic imaging results on TTE, CMR proved to be instrumental in visualizing a hemodynamically significant SV-ASD with PAPVR that ultimately led to surgical correction. PMID:25705227

Live-cell MRI with xenon hyper-CEST biosensors targeted to metabolically labeled cell-surface glycans.

PubMed

Witte, Christopher; Martos, Vera; Rose, Honor May; Reinke, Stefan; Klippel, Stefan; Schröder, Leif; Hackenberger, Christian P R

2015-02-23

The targeting of metabolically labeled glycans with conventional MRI contrast agents has proved elusive. In this work, which further expands the utility of xenon Hyper-CEST biosensors in cell experiments, we present the first successful molecular imaging of such glycans using MRI. Xenon Hyper-CEST biosensors are a novel class of MRI contrast agents with very high sensitivity. We designed a multimodal biosensor for both fluorescent and xenon MRI detection that is targeted to metabolically labeled sialic acid through bioorthogonal chemistry. Through the use of a state of the art live-cell bioreactor, it was demonstrated that xenon MRI biosensors can be used to image cell-surface glycans at nanomolar concentrations. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The visceral adiposity index is associated with insulin sensitivity and IGF-I levels in adults with growth hormone deficiency.

PubMed

Ciresi, Alessandro; Radellini, Stefano; Guarnotta, Valentina; Giordano, Carla

2017-06-01

The visceral adiposity index, based on anthropometric and metabolic parameters, has been shown to be related to adipose tissue function and insulin sensitivity. We aimed to evaluate the performance of the visceral adiposity index in adult patients with growth hormone deficiency. We enrolled 52 patients(mean age 51 ± 13 years) with newly diagnosed growth hormone deficiency and 50 matched healthy subjects as controls at baseline. At baseline and after 12 and 24 months of treatment we evaluated anthropometric measures, lipid profile, glucose and insulin during an oral glucose tolerance test, hemoglobin A1c, homeostasis model assessment estimate of insulin resistance, quantitative insulin sensitivity check index, insulin sensitivity index Matsuda, insulin-like growth factor-I and visceral adiposity index. At baseline growth hormone deficiency patients showed higher waist circumference (p < 0.001), low-density lipoprotein cholesterol (p < 0.001) and visceral adiposity index (p = 0.003) with lower insulin sensitivity index (p = 0.007) and high-density lipoprotein cholesterol (p = 0.001) than controls. During growth hormone treatment we observed a significant increase in insulin-like growth factor-I (p < 0.001), high-density lipoprotein (p < 0.001) with a trend toward increase in insulin sensitivity index (p = 0.055) and a significant decrease in total cholesterol (p < 0.001) and visceral adiposity index (p < 0.001), while no significant changes were observed in other clinical and metabolic parameters. The visceral adiposity index was the only parameter that significantly correlated with growth hormone peak at diagnosis (p < 0.001) and with insulin-like growth factor-I and insulin sensitivity index both at diagnosis (p = 0.009 and p < 0.001) and after 12 (p = 0.026 and p = 0.001) and 24 months (p < 0.001 and p = 0.001) of treatment. The visceral adiposity index, which has shown to be associated with both insulin-like growth factor-I and insulin sensitivity, proved to be the most reliable index of metabolic perturbation, among the most common indexes of adiposity assessment and a marker of benefit during treatment in adult growth hormone deficiency patients.

The Reusable Load Cell with Protection Applied for Online Monitoring of Overhead Transmission Lines Based on Fiber Bragg Grating

PubMed Central

Ma, Guoming; Mao, Naiqiang; Li, Yabo; Jiang, Jun; Zhou, Hongyang; Li, Chengrong

2016-01-01

Heavy ice coating of high–voltage overhead transmission lines may lead to conductor breakage and tower collapse causing the unexpected interrupt of power supply. The optical load cell applied in ice monitoring systems is immune to electromagnetic interference and has no need of a power supply on site. Therefore, it has become a hot research topic in China and other countries. In this paper, to solve the problem of eccentric load in measurement, we adopt the shearing structure with additional grooves to improve the strain distribution and acquire good repeatability. Then, the fiber Bragg grating (FBG) with a permanent weldable package are mounted onto the front/rear groove of the elastic element by spot welding, the direction deviation of FBGs is 90° from each other to achieve temperature compensation without an extra FBG. After that, protection parts are designed to guarantee high sensitivity for a light load condition and industrial safety under a heavy load up to 65 kN. The results of tension experiments indicate that the sensitivity and resolution of the load cell is 0.1285 pm/N and 7.782 N in the conventional measuring range (0–10 kN). Heavy load tension experiments prove that the protection structure works and the sensitivity and resolution are not changed after several high load (65 kN) cycles. In addition, the experiment shows that the resolution of the sensor is 87.79 N in the large load range, allowing the parameter to be used in heavy icing monitoring. PMID:27338403

Partial filling affinity capillary electrophoresis as a useful tool for fragment-based drug discovery: A proof of concept on thrombin.

PubMed

Farcaş, E; Bouckaert, C; Servais, A-C; Hanson, J; Pochet, L; Fillet, M

2017-09-01

With the emergence of more challenging targets, a relatively new approach, fragment-based drug discovery (FBDD), proved its efficacy and gained increasing importance in the pharmaceutical industry. FBDD identifies low molecular-weight (MW) ligands (fragments) that bind to biologically important macromolecules, then a structure-guided fragment growing or merging approach is performed, contributing to the quality of the lead. However, to select the appropriate fragment to be evolved, sensitive analytical screening methods must be used to measure the affinity in the μM or even mM range. In this particular context, we developed a robust and selective partial filling affinity CE (ACE) method for the direct binding screening of a small fragment library in order to identify new thrombin inhibitors. To demonstrate the accuracy of our assay, the complex dissociation constants of three known thrombin inhibitors, namely benzamidine, p-aminobenzamidine and nafamostat were determined and found to be in good concordance with the previously reported values. Finally, the screening of a small library was performed and demonstrated the high discriminatory power of our method towards weak binders compared to classical spectrophotometric activity assay, proving the interest of our method in the context of FBDD. Copyright © 2017 Elsevier B.V. All rights reserved.

Cerenkov luminescence tomography based on preconditioning orthogonal matching pursuit

NASA Astrophysics Data System (ADS)

Liu, Haixiao; Hu, Zhenhua; Wang, Kun; Tian, Jie; Yang, Xin

2015-03-01

Cerenkov luminescence imaging (CLI) is a novel optical imaging method and has been proved to be a potential substitute of the traditional radionuclide imaging such as positron emission tomography (PET) and single-photon emission computed tomography (SPECT). This imaging method inherits the high sensitivity of nuclear medicine and low cost of optical molecular imaging. To obtain the depth information of the radioactive isotope, Cerenkov luminescence tomography (CLT) is established and the 3D distribution of the isotope is reconstructed. However, because of the strong absorption and scatter, the reconstruction of the CLT sources is always converted to an ill-posed linear system which is hard to be solved. In this work, the sparse nature of the light source was taken into account and the preconditioning orthogonal matching pursuit (POMP) method was established to effectively reduce the ill-posedness and obtain better reconstruction accuracy. To prove the accuracy and speed of this algorithm, a heterogeneous numerical phantom experiment and an in vivo mouse experiment were conducted. Both the simulation result and the mouse experiment showed that our reconstruction method can provide more accurate reconstruction result compared with the traditional Tikhonov regularization method and the ordinary orthogonal matching pursuit (OMP) method. Our reconstruction method will provide technical support for the biological application for Cerenkov luminescence.

Creating Quadrilaterals from Quadrilaterals

ERIC Educational Resources Information Center

Nirode, Wayne

2016-01-01

A part of high school geometry is devoted to the study of parallelograms in the context of proving some of their properties using congruent triangles (CCSSI 2010). The typical high school geometry book's chapter on quadrilaterals focuses on parallelograms (e.g., their properties, proving that a given quadrilateral is a parallelogram, and special…

A Case Study of Culturally Sensitive Mail Survey Methods for Understanding Walking within an Orthodox Jewish Community

ERIC Educational Resources Information Center

Kahan, David

2006-01-01

Adequate response to mail health surveys by minority populations has proved problematic. The impact of mail survey design features utilized to promote Orthodox Jews' responses (N = 138; 82 eligible synagogue member households) to a mailed questionnaire used to measure walking behavior are described and assessed. An examination of response…

A Mixture Rasch Model with a Covariate: A Simulation Study via Bayesian Markov Chain Monte Carlo Estimation

ERIC Educational Resources Information Center

Dai, Yunyun

2013-01-01

Mixtures of item response theory (IRT) models have been proposed as a technique to explore response patterns in test data related to cognitive strategies, instructional sensitivity, and differential item functioning (DIF). Estimation proves challenging due to difficulties in identification and questions of effect size needed to recover underlying…

Comparison of techniques for detecting antigens of Giardia lamblia and Cryptosporidium parvum in faeces.

PubMed Central

Tee, G H; Moody, A H; Cooke, A H; Chiodini, P L

1993-01-01

AIM--To compare the use of commercial monoclonal antibody test systems--the Giardia CEL IF test and the Crypto CEL IF test--for the detection of Giardia lamblia and Cryptosporidium parvum antigens in faeces with conventional techniques. METHODS--Sensitivity and specificity were evaluated using preparations of cysts of G lamblia and purified oocysts of C parvum. Evaluation of 59 random faecal samples passing through the Department of Clinical Parasitology, Hospital for Tropical Diseases, London, was carried out for both organisms. RESULTS--The fluorescence staining techniques proved more sensitive than other tests routinely used for diagnosis. PMID:8331181

Batch Proving and Proof Scripting in PVS

NASA Technical Reports Server (NTRS)

Munoz, Cesar A.

2007-01-01

The batch execution modes of PVS are powerful, but highly technical, features of the system that are mostly accessible to expert users. This paper presents a PVS tool, called ProofLite, that extends the theorem prover interface with a batch proving utility and a proof scripting notation. ProofLite enables a semi-literate proving style where specification and proof scripts reside in the same file. The goal of ProofLite is to provide batch proving and proof scripting capabilities to regular, non-expert, users of PVS.

Midline corpus callosum is a neuroanatomical focus of fetal alcohol damage.

PubMed

Bookstein, Fred L; Sampson, Paul D; Connor, Paul D; Streissguth, Ann P

2002-06-15

Prenatal exposure to high levels of alcohol often induces birth defects that combine morphological stigmata with neurological or neuropsychological deficits. But it has proved problematic to diagnose these syndromes in adolescents and adults, in whom the morphological signs are absent or attenuated, the behavioral deficits nonspecific, and the exposure history often difficult to reconstruct. Localizing the associated brain abnormalities might circumvent most of these difficulties. To this end, three-dimensional (3D) locations were recorded for 67 homologous points on or near the corpus callosum in magnetic resonance (MR) brain images from 60 adolescents and adults who were normal, 60 diagnosed with fetal alcohol syndrome, and 60 diagnosed with fetal alcohol effects. We combined the standard statistical approach to this type of geometric data, Procrustes analysis, with a multivariate strategy focusing on differences in variability. In this data set, the shape of the corpus callosum and its vicinity proves systematically much more variable in the alcohol-affected brains than in those of the normal subjects. From this excess variability follows a promising classification rule, having both high sensitivity (100 out of 117) and high specificity (49 out of 60) in this sample. The discrimination uses four landmark points and two summary scores of callosal outline shape. The information from the corpus callosum and vicinity, as viewed in MR brain images of full-grown subjects, may serve as a permanent record of the prenatal effects of alcohol, even in patients who are first suspected of these syndromes relatively late in life or who lack the facial signs of prenatal alcohol damage. The statistical pattern underlying the callosal diagnosis also leads to speculations on mechanisms of the prenatal damage. Copyright 2002 Wiley-Liss, Inc.

An integrative machine learning strategy for improved prediction of essential genes in Escherichia coli metabolism using flux-coupled features.

PubMed

Nandi, Sutanu; Subramanian, Abhishek; Sarkar, Ram Rup

2017-07-25

Prediction of essential genes helps to identify a minimal set of genes that are absolutely required for the appropriate functioning and survival of a cell. The available machine learning techniques for essential gene prediction have inherent problems, like imbalanced provision of training datasets, biased choice of the best model for a given balanced dataset, choice of a complex machine learning algorithm, and data-based automated selection of biologically relevant features for classification. Here, we propose a simple support vector machine-based learning strategy for the prediction of essential genes in Escherichia coli K-12 MG1655 metabolism that integrates a non-conventional combination of an appropriate sample balanced training set, a unique organism-specific genotype, phenotype attributes that characterize essential genes, and optimal parameters of the learning algorithm to generate the best machine learning model (the model with the highest accuracy among all the models trained for different sample training sets). For the first time, we also introduce flux-coupled metabolic subnetwork-based features for enhancing the classification performance. Our strategy proves to be superior as compared to previous SVM-based strategies in obtaining a biologically relevant classification of genes with high sensitivity and specificity. This methodology was also trained with datasets of other recent supervised classification techniques for essential gene classification and tested using reported test datasets. The testing accuracy was always high as compared to the known techniques, proving that our method outperforms known methods. Observations from our study indicate that essential genes are conserved among homologous bacterial species, demonstrate high codon usage bias, GC content and gene expression, and predominantly possess a tendency to form physiological flux modules in metabolism.

Investigating the Effect of Impurities on Macromolecule Crystal Growth in Microgravity

NASA Technical Reports Server (NTRS)

Snell, Edward H.; Judge, Russell A.; Crawford, Lisa; Forsythe, Elizabeth L.; Pusey, Marc L.; Sportiello, Michael; Todd, Paul; Bellamy, Henry; Lovelace, Jeff; Cassanto, John M.;

Pairing attachment theory and social learning theory in video-feedback intervention to promote positive parenting.

PubMed

Juffer, Femmie; Bakermans-Kranenburg, Marian J; van IJzendoorn, Marinus H

2017-06-01

Video-feedback Intervention to promote Positive Parenting and Sensitive Discipline (VIPP-SD) is a social-learning and attachment-based intervention using video feedback to support sensitive parenting and at the same time setting firm limits. Empirical studies and meta-analyses have shown that sensitive parenting is the key determinant to promote secure child-parent attachment relationships and that adequate parental discipline contributes to fewer behavior problems in children. Building on this evidence, VIPP-SD has been tested in various populations of at-risk parents and vulnerable children (in the age range of zero to six years), as well as in the context of child care. In twelve randomized controlled trials including 1116 parents and caregivers, VIPP-SD proved to be effective in promoting sensitive caregiving, while positive social-emotional child outcomes were also found. Copyright © 2017 Elsevier Ltd. All rights reserved.

Exponential Sensitivity and its Cost in Quantum Physics

PubMed Central

Gilyén, András; Kiss, Tamás; Jex, Igor

2016-01-01

State selective protocols, like entanglement purification, lead to an essentially non-linear quantum evolution, unusual in naturally occurring quantum processes. Sensitivity to initial states in quantum systems, stemming from such non-linear dynamics, is a promising perspective for applications. Here we demonstrate that chaotic behaviour is a rather generic feature in state selective protocols: exponential sensitivity can exist for all initial states in an experimentally realisable optical scheme. Moreover, any complex rational polynomial map, including the example of the Mandelbrot set, can be directly realised. In state selective protocols, one needs an ensemble of initial states, the size of which decreases with each iteration. We prove that exponential sensitivity to initial states in any quantum system has to be related to downsizing the initial ensemble also exponentially. Our results show that magnifying initial differences of quantum states (a Schrödinger microscope) is possible; however, there is a strict bound on the number of copies needed. PMID:26861076

Assessment of activity in Sarcoidosis. Sensitivity and specificity of 67Gallium scintigraphy, serum ACE levels, chest roentgenography, and blood lymphocyte subpopulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Klech, H.; Kohn, H.; Kummer, F.

1982-12-01

The value of different factors are examined to assess activity in 60 patients with biopsy-proven sarcoidosis. In patients with active sarcoidosis (n . 35), /sup 67/Ga scans proved to be the most sensitive method (94 percent sensitivity), followed by serum angiotensin I converting enzyme (S-ACE) levels, chest x-ray films, and lymphocyte assays. In patients with peripheral pulmonary lesions, chest x-ray films failed in 32 percent of cases to document activity (68 percent sensitivity) whereas /sup 67/Ga scans and S-ACE levels remained to give reliable results. Despite poor specificity, negative /sup 67/Ga scans together with normal ACE levels have a highmore » predictive value for exclusion of active sarcoidosis. In patients with peripheral pulmonary lesions, chest roentgenography is of doubtful value for staging lung involvement and assessment of activity including monitoring and control of therapy.« less

Exponential Sensitivity and its Cost in Quantum Physics.

PubMed

Gilyén, András; Kiss, Tamás; Jex, Igor

2016-02-10

State selective protocols, like entanglement purification, lead to an essentially non-linear quantum evolution, unusual in naturally occurring quantum processes. Sensitivity to initial states in quantum systems, stemming from such non-linear dynamics, is a promising perspective for applications. Here we demonstrate that chaotic behaviour is a rather generic feature in state selective protocols: exponential sensitivity can exist for all initial states in an experimentally realisable optical scheme. Moreover, any complex rational polynomial map, including the example of the Mandelbrot set, can be directly realised. In state selective protocols, one needs an ensemble of initial states, the size of which decreases with each iteration. We prove that exponential sensitivity to initial states in any quantum system has to be related to downsizing the initial ensemble also exponentially. Our results show that magnifying initial differences of quantum states (a Schrödinger microscope) is possible; however, there is a strict bound on the number of copies needed.

Determination of pharmaceutical and illicit drugs in oral fluid by ultra-high performance liquid chromatography-tandem mass spectrometry.

PubMed

Di Corcia, D; Lisi, S; Pirro, V; Gerace, E; Salomone, A; Vincenti, M

2013-05-15

A simple and extremely fast procedure for the quantitative determination in oral fluid samples of 44 substances, including the most common drugs of abuse and several pharmaceutical drugs, was developed and fully validated. Preliminary sample treatment was limited to protein precipitation. The resulting acetonitrile solution was directly injected into an ultra-high performance liquid chromatograph (UHPLC) equipped with a C18 column (100mm×2.1mm, 1.7μm). The mobile phase eluted with linear gradient (water/formic acid 5mM: acetonitrile/formic acid 5mM; v:v) from 98:2 to 0:100 in 5.0min, followed by isocratic elution at 100% B for 1.0min. The flow rate was 0.6mL/min and the total run time was 9.0min including re-equilibration at the initial conditions. The analytes were revealed by a triple quadrupole mass spectrometer operating in the selected reaction monitoring mode. The method proved to be simple, accurate, rapid and highly sensitive, allowing the simultaneous detection of all compounds. The ease of sample treatment, together with the wide range of detectable substances, all with remarkable analytical sensitivity, make this procedure ideal for the screening of large populations in several forensic and clinical contexts, whenever oral fluid sampling has to be preferred to blood sampling, as for example in short retrospective investigations. Copyright © 2013 Elsevier B.V. All rights reserved.

On the direct detection of gravitational waves

NASA Astrophysics Data System (ADS)

Pustovoit, V. I.

2016-10-01

Different types of gravitational wave (GW) detectors are considered. It is noted that interferometric techniques offer the greatest prospects for GW registration due to their high sensitivity and extremely wide frequency band. Using laser interferometers, proposed as far back as 1962 in the work by M E Gertsenshtein and V I Pustovoit published in Russian (Zh. Eksp. Teor. Fiz., vol. 43, p. 605, 1962) and in English translation (Sov. Phys. JETP, vol. 16, p. 433, 1963), it proved possible for the first time to directly detect GW emission from a merger of two black holes. It is noted that the assertion that Gertsen-shtein-Pustovoit's work was unknown to some of those experts involved in direct GW detection is inconsistent with reality. The problems of high-power laser radiation affecting the electrostatic polarization of free-mass mirrors are discussed. It is shown that mirror polarization can lead to additional links with electrically conducting elements of the design resulting in the interferometer's reduced sensitivity. Some new prospects for developing high reflection structures are discussed and heat extraction problems are considered. This article is the revised and extended version of the report “On the first direct detection of gravitational waves” delivered by V I Pustovoit at the Scientific Session of the Physical Sciences Division of the Russian Academy of Sciences (March 2, 2016). All other reports presented at the session were published in the preceding issue of Physics-Uspekhi (September 2016) (see Refs [108, 111-113]). (Editorial note)

Affinity purification of the voltage-sensitive sodium channel from electroplax with resins selective for sialic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

James, W.M.; Emerick, M.C.; Agnew, W.S.

1989-07-11

The voltage-sensitive sodium channel present in the eel (Electrophorus electricus) has an unusually high content of sialic acid, including {alpha}-(2{yields}8)-linked polysialic acid, not found in other electroplax membrane glycopeptides. Lectins from Limax flavus (LFA) and wheat germ (WGA) proved the most effective of 11 lectin resins tried. The most selective resin was prepared from IgM antibodies against Neisseria meningitidis {alpha}-(2{yields}8)-polysialic acid which were affinity purified and coupled to Sepharose 4B. The sodium channel was found to bind to WGA, LFA, and IgM resins and was readily eluted with the appropriate soluble carbohydrates. Experiments with LFA and IgM resins demonstrated bindingmore » and unbinding rates and displacement kinetics, which suggest highly specific binding at multiple sites on the sodium channel protein. In preparative-scale purification of protein previously fractionated by anion-exchange chromatography, without stabilizing TTX, high yields were reproducibly obtained. Further, when detergent extracts were prepared from electroplax membranes fractionated by low-speed sedimentation, a single step over the IgM resin provided a 70-fold purification, yielding specific activities of 3,200 pmol of ({sup 3}H)TTX-binding sites/mg of protein and a single polypeptide of {approximately}285,000 Da on SDS-acrylamide gels. No small peptides were observed after this 5-h isolation. The authors describe a cation-dependent stabilization with millimolar levels of monovalent and micromolar levels of divalent species.« less

Solid-state infrared-to-visible upconversion sensitized by colloidal nanocrystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Mengfei; Congreve, Daniel N.; Wilson, Mark W. B.

2015-11-23

Optical upconversion via sensitized triplet–triplet exciton annihilation converts incoherent low-energy photons to shorter wavelengths under modest excitation intensities1,2,3. Here, we report a solid-state thin film for infrared-to-visible upconversion that employs lead sulphide colloidal nanocrystals as a sensitizer. Upconversion is achieved from pump wavelengths beyond λ = 1 μm to emission at λ = 612 nm. When excited at λ = 808 nm, two excitons in the sensitizer are converted to one higher-energy state in the emitter at a yield of 1.2 ± 0.2%. Peak efficiency is attained at an absorbed intensity equivalent to less than one sun. We demonstrate thatmore » colloidal nanocrystals are an attractive alternative to existing molecular sensitizers, given their small exchange splitting, wide wavelength tunability, broadband infrared absorption, and our transient observations of efficient energy transfer. This solid-state architecture for upconversion may prove useful for enhancing the capabilities of solar cells and photodetectors.« less

Solid-state infrared-to-visible upconversion sensitized by colloidal nanocrystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Mengfei; Congreve, Daniel N.; Wilson, Mark W. B.

2015-11-23

Optical upconversion via sensitized triplet–triplet exciton annihilation converts incoherent low-energy photons to shorter wavelengths under modest excitation intensities1, 2, 3. Here, we report a solid-state thin film for infrared-to-visible upconversion that employs lead sulphide colloidal nanocrystals as a sensitizer. Upconversion is achieved from pump wavelengths beyond λ = 1 μm to emission at λ = 612 nm. When excited at λ = 808 nm, two excitons in the sensitizer are converted to one higher-energy state in the emitter at a yield of 1.2 ± 0.2%. Peak efficiency is attained at an absorbed intensity equivalent to less than one sun. Wemore » demonstrate that colloidal nanocrystals are an attractive alternative to existing molecular sensitizers, given their small exchange splitting, wide wavelength tunability, broadband infrared absorption, and our transient observations of efficient energy transfer. This solid-state architecture for upconversion may prove useful for enhancing the capabilities of solar cells and photodetectors.« less

Efficient Simulation of Wing Modal Response: Application of 2nd Order Shape Sensitivities and Neural Networks

NASA Technical Reports Server (NTRS)

Kapania, Rakesh K.; Liu, Youhua

2000-01-01

At the preliminary design stage of a wing structure, an efficient simulation, one needing little computation but yielding adequately accurate results for various response quantities, is essential in the search of optimal design in a vast design space. In the present paper, methods of using sensitivities up to 2nd order, and direct application of neural networks are explored. The example problem is how to decide the natural frequencies of a wing given the shape variables of the structure. It is shown that when sensitivities cannot be obtained analytically, the finite difference approach is usually more reliable than a semi-analytical approach provided an appropriate step size is used. The use of second order sensitivities is proved of being able to yield much better results than the case where only the first order sensitivities are used. When neural networks are trained to relate the wing natural frequencies to the shape variables, a negligible computation effort is needed to accurately determine the natural frequencies of a new design.

Solid-state infrared-to-visible upconversion sensitized by colloidal nanocrystals

NASA Astrophysics Data System (ADS)

Wu, Mengfei; Congreve, Daniel N.; Wilson, Mark W. B.; Jean, Joel; Geva, Nadav; Welborn, Matthew; van Voorhis, Troy; Bulović, Vladimir; Bawendi, Moungi G.; Baldo, Marc A.

2016-01-01

Optical upconversion via sensitized triplet-triplet exciton annihilation converts incoherent low-energy photons to shorter wavelengths under modest excitation intensities. Here, we report a solid-state thin film for infrared-to-visible upconversion that employs lead sulphide colloidal nanocrystals as a sensitizer. Upconversion is achieved from pump wavelengths beyond λ = 1 μm to emission at λ = 612 nm. When excited at λ = 808 nm, two excitons in the sensitizer are converted to one higher-energy state in the emitter at a yield of 1.2 ± 0.2%. Peak efficiency is attained at an absorbed intensity equivalent to less than one sun. We demonstrate that colloidal nanocrystals are an attractive alternative to existing molecular sensitizers, given their small exchange splitting, wide wavelength tunability, broadband infrared absorption, and our transient observations of efficient energy transfer. This solid-state architecture for upconversion may prove useful for enhancing the capabilities of solar cells and photodetectors.

Computing and analyzing the sensitivity of MLP due to the errors of the i.i.d. inputs and weights based on CLT.

PubMed

Yang, Sheng-Sung; Ho, Chia-Lu; Siu, Sammy

2010-12-01

In this paper, we propose an algorithm based on the central limit theorem to compute the sensitivity of the multilayer perceptron (MLP) due to the errors of the inputs and weights. For simplicity and practicality, all inputs and weights studied here are independently identically distributed (i.i.d.). The theoretical results derived from the proposed algorithm show that the sensitivity of the MLP is affected by the number of layers and the number of neurons adopted in each layer. To prove the reliability of the proposed algorithm, some experimental results of the sensitivity are also presented, and they match the theoretical ones. The good agreement between the theoretical results and the experimental results verifies the reliability and feasibility of the proposed algorithm. Furthermore, the proposed algorithm can also be applied to compute precisely the sensitivity of the MLP with any available activation functions and any types of i.i.d. inputs and weights.

Utility and limitations of a peptide reactivity assay to predict fragrance allergens in vitro.

PubMed

Natsch, A; Gfeller, H; Rothaupt, M; Ellis, G

2007-10-01

A key step in the skin sensitization process is the formation of a covalent adduct between the skin sensitizer and endogenous proteins and/or peptides in the skin. A published peptide depletion assay was used to relate the in vitro reactivity of fragrance molecules to LLNA data. Using the classical assay, 22 of 28 tested moderate to strong sensitizers were positive. The prediction of weak sensitizers proved to be more difficult with only 50% of weak sensitizers giving a positive response, but for some compounds this could also be due to false-positive results from the LLNA. LC-MS analysis yielded the expected mass of the peptide adducts in several cases, whereas in other cases putative oxidation reactions led to adducts of unexpected molecular weight. Several moderately sensitizing aldehydes were correctly predicted by the depletion assay, but no adducts were found and the depletion appears to be due to an oxidation of the parent peptide catalyzed by the test compound. Finally, alternative test peptides derived from a physiological reactive protein with enhanced sensitivity for weak Michael acceptors were found, further increasing the sensitivity of the assay.

Drama-induced affect and pain sensitivity.

PubMed

Zillmann, D; de Wied, M; King-Jablonski, C; Jenzowsky, S

1996-01-01

This study was conducted to examine the pain-ameliorating and pain-sensitizing effects of exposure to emotionally engaging drama. Specifically, the consequences for pain sensitivity of exposure to dramatic expositions differing in both excitatory and hedonic qualities were determined. Hedonically negative, neutral, and positive affective states were induced in male respondents by exposure to excerpts from cinematic drama. Pain sensitivity was assessed by the cuff-pressure procedure before and after exposure and by the cold pressor test after exposure only. When compared against the control condition, pain sensitivity diminished under conditions of hedonically positive affect. An inverse effect was suggested for hedonically negative conditions, but proved tentative and statistically unreliable. The findings are consistent with earlier demonstrations of mood effects on pain sensitivity. Unlike inconclusive earlier findings concerning the magnitude of directional effects, however, they suggest an asymmetry that emphasizes the pain-ameliorating effect of positive affects while lending little, if any, support to the proposal of a pain-sensitizing effect of negative affects. The investigation did not accomplish the intended creation of conditions necessary to test the proposal that heightened sympathetic activity diminishes pain sensitivity. The utility of a rigorous determination of this hypothesized relationship is emphasized, and procedures for a viable test of the proposal are suggested.

Circuit design for the retina-like image sensor based on space-variant lens array

NASA Astrophysics Data System (ADS)

Gao, Hongxun; Hao, Qun; Jin, Xuefeng; Cao, Jie; Liu, Yue; Song, Yong; Fan, Fan

2013-12-01

Retina-like image sensor is based on the non-uniformity of the human eyes and the log-polar coordinate theory. It has advantages of high-quality data compression and redundant information elimination. However, retina-like image sensors based on the CMOS craft have drawbacks such as high cost, low sensitivity and signal outputting efficiency and updating inconvenience. Therefore, this paper proposes a retina-like image sensor based on space-variant lens array, focusing on the circuit design to provide circuit support to the whole system. The circuit includes the following parts: (1) A photo-detector array with a lens array to convert optical signals to electrical signals; (2) a strobe circuit for time-gating of the pixels and parallel paths for high-speed transmission of the data; (3) a high-precision digital potentiometer for the I-V conversion, ratio normalization and sensitivity adjustment, a programmable gain amplifier for automatic generation control(AGC), and a A/D converter for the A/D conversion in every path; (4) the digital data is displayed on LCD and stored temporarily in DDR2 SDRAM; (5) a USB port to transfer the data to PC; (6) the whole system is controlled by FPGA. This circuit has advantages as lower cost, larger pixels, updating convenience and higher signal outputting efficiency. Experiments have proved that the grayscale output of every pixel basically matches the target and a non-uniform image of the target is ideally achieved in real time. The circuit can provide adequate technical support to retina-like image sensors based on space-variant lens array.

Validation of high throughput screening of human sera for detection of anti-PA IgG by Enzyme-Linked Immunosorbent Assay (ELISA) as an emergency response to an anthrax incident

PubMed Central

Semenova, Vera A.; Steward-Clark, Evelene; Maniatis, Panagiotis; Epperson, Monica; Sabnis, Amit; Schiffer, Jarad

2017-01-01

To improve surge testing capability for a response to a release of Bacillus anthracis, the CDC anti-Protective Antigen (PA) IgG Enzyme-Linked Immunosorbent Assay (ELISA) was re-designed into a high throughput screening format. The following assay performance parameters were evaluated: goodness of fit (measured as the mean reference standard r2), accuracy (measured as percent error), precision (measured as coefficient of variance (CV)), lower limit of detection (LLOD), lower limit of quantification (LLOQ), dilutional linearity, diagnostic sensitivity (DSN) and diagnostic specificity (DSP). The paired sets of data for each sample were evaluated by Concordance Correlation Coefficient (CCC) analysis. The goodness of fit was 0.999; percent error between the expected and observed concentration for each sample ranged from −4.6% to 14.4%. The coefficient of variance ranged from 9.0% to 21.2%. The assay LLOQ was 2.6 μg/mL. The regression analysis results for dilutional linearity data were r2 = 0.952, slope = 1.02 and intercept = −0.03. CCC between assays was 0.974 for the median concentration of serum samples. The accuracy and precision components of CCC were 0.997 and 0.977, respectively. This high throughput screening assay is precise, accurate, sensitive and specific. Anti-PA IgG concentrations determined using two different assays proved high levels of agreement. The method will improve surge testing capability 18-fold from 4 to 72 sera per assay plate. PMID:27814939

Validation of high throughput screening of human sera for detection of anti-PA IgG by Enzyme-Linked Immunosorbent Assay (ELISA) as an emergency response to an anthrax incident.

PubMed

Semenova, Vera A; Steward-Clark, Evelene; Maniatis, Panagiotis; Epperson, Monica; Sabnis, Amit; Schiffer, Jarad

2017-01-01

To improve surge testing capability for a response to a release of Bacillus anthracis, the CDC anti-Protective Antigen (PA) IgG Enzyme-Linked Immunosorbent Assay (ELISA) was re-designed into a high throughput screening format. The following assay performance parameters were evaluated: goodness of fit (measured as the mean reference standard r 2 ), accuracy (measured as percent error), precision (measured as coefficient of variance (CV)), lower limit of detection (LLOD), lower limit of quantification (LLOQ), dilutional linearity, diagnostic sensitivity (DSN) and diagnostic specificity (DSP). The paired sets of data for each sample were evaluated by Concordance Correlation Coefficient (CCC) analysis. The goodness of fit was 0.999; percent error between the expected and observed concentration for each sample ranged from -4.6% to 14.4%. The coefficient of variance ranged from 9.0% to 21.2%. The assay LLOQ was 2.6 μg/mL. The regression analysis results for dilutional linearity data were r 2  = 0.952, slope = 1.02 and intercept = -0.03. CCC between assays was 0.974 for the median concentration of serum samples. The accuracy and precision components of CCC were 0.997 and 0.977, respectively. This high throughput screening assay is precise, accurate, sensitive and specific. Anti-PA IgG concentrations determined using two different assays proved high levels of agreement. The method will improve surge testing capability 18-fold from 4 to 72 sera per assay plate. Published by Elsevier Ltd.

Significant enhancement of 11-Hydroxy-THC detection by formation of picolinic acid esters and application of liquid chromatography/multi stage mass spectrometry (LC-MS(3) ): Application to hair and oral fluid analysis.

PubMed

Thieme, Detlef; Sachs, Ulf; Sachs, Hans; Moore, Christine

2015-07-01

Formation of picolinic acid esters of hydroxylated drugs or their biotransformation products is a promising tool to improve their mass spectrometric ionization efficiency, alter their fragmentation behaviour and enhance sensitivity and specificity of their detection. The procedure was optimized and tested for the detection of cannabinoids, which proved to be most challenging when dealing with alternative specimens, for example hair and oral fluid. In particular, the detection of the THC metabolites hydroxyl-THC and carboxy-THC requires ultimate sensitivity because of their poor incorporation into hair or saliva. Both biotransformation products are widely accepted as incorporation markers to distinguish drug consumption from passive contamination. The derivatization procedure was carried out by adding a mixture of picolinic acid, 4-(dimethylamino)pyridine and 2-methyl-6-nitrobenzoic anhydride in tetrahydrofuran/triethylamine to the dry extraction residues. Resulting derivatives were found to be very stable and could be reconstituted in aqueous or organic buffers and subsequently analyzed by liquid chromatography-mass spectrometry (LC-MS). Owing to the complex consecutive fragmentation patterns, the application of multistage MS3 proved to be extremely useful for a sensitive identification of doubly picolinated hydroxy-THC in complex matrices. The detection limits - estimated by comparison of corresponding signal-to-noise ratios - increased by a factor of 100 following picolination. All other species examined, like cannabinol, THC, cannabidiol, and carboxy-THC, could also be derivatized exhibiting only moderate sensitivity improvements. The assay was systematically tested using hair samples and exemplarily applied to oral fluid. Concentrations of OH-THC identified in THC-positive hair samples ranged from 0.02 to 0.29pg/mg. Copyright © 2014 John Wiley & Sons, Ltd.

Sensitivity of Helicobacter pylori detection by Giemsa staining is poor in comparison with immunohistochemistry and fluorescent in situ hybridization and strongly depends on inflammatory activity.

PubMed

Kocsmár, Éva; Szirtes, Ildikó; Kramer, Zsófia; Szijártó, Attila; Bene, László; Buzás, György Miklós; Kenessey, István; Bronsert, Peter; Csanadi, Agnes; Lutz, Lisa; Werner, Martin; Wellner, Ulrich Friedrich; Kiss, András; Schaff, Zsuzsa; Lotz, Gábor

2017-08-01

Conventional stainings (including H&E and special stains like Giemsa) are the most widely applied histopathologic detection methods of Helicobacter pylori (HP). We aimed to compare the diagnostic performance of Giemsa staining with immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) on a monocentric cohort of 2896 gastric biopsies and relate results to histologic alterations in order to find such histopathologic subgroups in which these methods underperform. All cases were categorized regarding presence or absence of chronic gastritis, inflammatory activity, and mucosal structural alterations. Giemsa revealed 687 cases (23.7%), IHC 795 cases (27.5%), and FISH 788 cases (27.2%) as being HP positive. Giemsa showed significantly lower overall sensitivity (83.3%) compared to IHC (98.8%) and FISH (98.0%). Moreover, the sensitivity of Giemsa dramatically dropped to 33.6% in the nonactive cases. We found that sensitivity of Giemsa strongly depends on HP density and, accordingly, on the presence of activity. Structural alterations (intestinal metaplasia, atrophy, etc.) had only no or weak effect on sensitivity of the three stainings. Both IHC and FISH proved to be equally reliable HP detecting techniques whose diagnostic performance is minimally influenced by mucosal inflammatory and structural alterations contrary to conventional stainings. We highly recommend immunohistochemistry for clinically susceptible, nonactive chronic gastritis cases, if the conventional stain-based HP detection is negative. Moreover, we recommend to use IHC more widely as basic HP stain. Helicobacter pylori FISH technique is primarily recommended to determine bacterial clarithromycin resistance. Furthermore, it is another accurate diagnostic tool for HP. © 2017 John Wiley & Sons Ltd.

On the origin of increased sensitivity and mass resolution using silicon masks in MALDI.

PubMed

Diologent, Laurent; Franck, Julien; Wisztorski, Maxence; Treizebre, Anthony; Focsa, Cristian; Fournier, Isabelle; Ziskind, Michael

2014-02-04

Since its development, MALDI has proved its performance in the analysis of intact biomolecules up to high molecular weights, regardless of their polarity. Sensitivity of MALDI instruments is a key point for breaking the limits of observing biomolecules of lower abundances. Instrumentation is one way to improve sensitivity by increasing ion transmission and using more sensitive detection systems. On the other side, improving MALDI ion production yields would have important outcomes. MALDI ion production is still not well-controlled and, indeed, the amount of ions produced per laser shot with respect to the total volume of desorbed material is very low. This has particular implications for certain applications, such as MALDI MS imaging where laser beam focusing as fine as possible (5-10 μm) is searched in order to reach higher spatial resolution images. However, various studies point out an intrinsic decrease in signal intensity for strong focusing. We have therefore been interested in developing silicon mask systems to decrease an irradiated area by cutting rather than focusing the laser beam and to study the parameters affecting sensitivity using such systems. For this, we systematically examined variation with laser fluence of intensity and spectral resolution in MALDI of standard peptides when using silicon-etched masks of various aperture sizes. These studies demonstrate a simultaneous increase in spectral resolution and signal intensity. Origin of this effect is discussed in the frame of the two-step ionization model. Experimental data in the low fluence range are fitted with an increase of the primary ionization through matrix-silicon edge contact provided by the masks. On the other hand, behavior at higher fluence could be explained by an effect on the secondary ionization via changes in the plume dynamics.

Sensitivity and specificity of the circulating cathodic antigen rapid urine test in the diagnosis of Schistosomiasis mansoni infection and evaluation of morbidity in a low- endemic area in Brazil.

PubMed

Ferreira, Fernanda Teixeira; Fidelis, Thiago André; Pereira, Thiago Almeida; Otoni, Alba; Queiroz, Leonardo Campos; Amâncio, Frederico Figueiredo; Antunes, Carlos Maurício; Lambertucci, José Roberto

2017-01-01

The Kato-Katz technique is the standard diagnostic test for Schistosoma mansoni infection in rural areas. However, the utility of this method is severely limited by the day-to-day variability in host egg excretion in the stool. In high-transmission areas, the point-of-care circulating cathodic antigen (POC-CCA) urine assay has proven to be a reliable test. However, investigations of the reliability of the POC-CCA assay in low-transmission regions are under way. This study aimed to evaluate the sensitivity and specificity of the POC-CCA assay and the morbidity of schistosomiasis in a low-endemic area in Brazil. Pains City is a low-transmission zone for schistosomiasis. A total of 300 subjects aged 7-76 years were randomly selected for the POC-CCA cassette test. For S. mansoni diagnosis, three stool samples on six slides were compared with one urine sample for each subject. The sensitivity and specificity in the absence of a gold standard were calculated using latent class analysis. Clinical examinations and abdominal ultrasounds were performed in 181 volunteers to evaluate morbidity associated with schistosomiasis. The sensitivity and specificity of the Kato-Katz technique were 25.6% and 94.6%, respectively. By contrast, the sensitivity and specificity of the POC-CCA assay were 68.1% and 72.8%, respectively. Hepatosplenic schistosomiasis was diagnosed in two patients (1.1%). Overall, the POC-CCA urine assay proved to be a useful test for diagnosing S. mansoni in a low-endemic area in Brazil. Severe clinical forms of schistosomiasis can be present even in such low-endemic areas.

Streptococcus A in paediatric accident and emergency: are rapid streptococcal tests and clinical examination of any help?

PubMed

Van Limbergen, J; Kalima, P; Taheri, S; Beattie, T F

2006-01-01

Rapid streptococcal tests (RSTs) for streptococcal pharyngitis have made diagnosis at once simpler and more complicated. The American Academy of Pediatrics recommends that all RSTs be confirmed by a follow up throat culture unless local validation has proved the RST to be equally sensitive. To evaluate (a) RST as a single diagnostic tool, compared with RST with or without throat culture; (b) clinical diagnosis and the relative contribution of different symptoms. The study included 213 patients with clinical signs of pharyngitis. Throat swabs were analysed using Quickvue+ Strep A Test; negative RSTs were backed up by throat culture. Thirteen clinical features commonly associated with strep throat were analysed using backward stepwise logistic regression. Positive results (RST or throat culture) were obtained in 33 patients; RST correctly identified 21. Eleven samples were false negative on RST. At a strep throat prevalence of 15.9%, sensitivity of RST was 65.6% (95% CI 46.8% to 81.4%) and specificity 99.4% (96.7% to 99.9%). Sensitivity of clinical diagnosis alone was 57% (34% to 78%) and specificity 71% (61% to 80%). Clinically, only history of sore throat, rash, and pyrexia contributed to the diagnosis of strep throat (p<0.05). The high specificity of RST facilitates early diagnosis of strep throat. However, the low sensitivity of RST does not support its use as a single diagnostic tool. The sensitivity in the present study is markedly different from that reported by the manufacturer. Clinical examination is of limited value in the diagnosis of strep throat. It is important to audit the performance of new diagnostic tests, previously validated in different settings.

Streptococcus A in paediatric accident and emergency: are rapid streptococcal tests and clinical examination of any help?

PubMed Central

Van Limbergen, J; Kalima, P; Taheri, S; Beattie, T F

2006-01-01

Background Rapid streptococcal tests (RSTs) for streptococcal pharyngitis have made diagnosis at once simpler and more complicated. The American Academy of Pediatrics recommends that all RSTs be confirmed by a follow up throat culture unless local validation has proved the RST to be equally sensitive. Aims To evaluate (a) RST as a single diagnostic tool, compared with RST with or without throat culture; (b) clinical diagnosis and the relative contribution of different symptoms. Methods The study included 213 patients with clinical signs of pharyngitis. Throat swabs were analysed using Quickvue+ Strep A Test; negative RSTs were backed up by throat culture. Thirteen clinical features commonly associated with strep throat were analysed using backward stepwise logistic regression. Results Positive results (RST or throat culture) were obtained in 33 patients; RST correctly identified 21. Eleven samples were false negative on RST. At a strep throat prevalence of 15.9%, sensitivity of RST was 65.6% (95% CI 46.8% to 81.4%) and specificity 99.4% (96.7% to 99.9%). Sensitivity of clinical diagnosis alone was 57% (34% to 78%) and specificity 71% (61% to 80%). Clinically, only history of sore throat, rash, and pyrexia contributed to the diagnosis of strep throat (p<0.05). Conclusion The high specificity of RST facilitates early diagnosis of strep throat. However, the low sensitivity of RST does not support its use as a single diagnostic tool. The sensitivity in the present study is markedly different from that reported by the manufacturer. Clinical examination is of limited value in the diagnosis of strep throat. It is important to audit the performance of new diagnostic tests, previously validated in different settings. PMID:16373800

One-step cross-genogroup multiplex RT-qPCR with an internal control system for the detection of infectious pancreatic necrosis virus (IPNV).

PubMed

Hoferer, Marc; Braun, Anne; Skrypski, Julia; Bock, Sabine; Thalheim, Sabine; Sting, Reinhard

2017-09-01

Infectious pancreatic necrosis virus (IPNV) causes great losses in fish hatcheries world-wide. The detection of IPNV can be challenging in certain circumstances, particularly due to low viral load and the genetic variability of this RNA virus. For the first time, this project created a quantitative triplex real-time reverse transcription PCR (RT-qPCR), including an endogenous control system, for specific, sensitive and rapid detection of IPNV in routine diagnostics. Multiple sequence alignment of 46 nucleotide sequences of the segment A genome obtained from the NCBI database allowed the design of two RT-qPCR systems covering the IPNV genogroup 1 and genogroups 2-5, respectively. The completed triplex RT-qPCR including a salmonid-specific endogenous control showed high specificity and an analytical sensitivity of 20-40 oligonucleotide copies. Testing of dilution series of virus-loaded cell culture suspensions proved equality of the triplex RT-qPCR with virus detection in cell culture and a higher sensitivity than conventional RT-PCR in field samples. In comparative studies of a total of 77 field samples tested, 51 showed identical positive and 19 identical negative results in cell culture and the triplex RT-qPCR. However, seven other samples yielded positive results in the triplex RT-qPCR, but negative results in cell culture. Copyright © 2017 Elsevier B.V. All rights reserved.

IgE sensitization to Anisakis pegreffii in Italy: Comparison of two methods for the diagnosis of allergic anisakiasis.

PubMed

Mattiucci, S; Colantoni, A; Crisafi, B; Mori-Ubaldini, F; Caponi, L; Fazii, P; Nascetti, G; Bruschi, F

2017-07-01

IgE sensitization to Anisakis pegreffii in Italian subjects suffering from gastro-allergic anisakiasis (GAA) (N=5), or showing chronic urticaria (CU+) after fish consumption (N=100), was investigated. A control group (N=5) was also included. IgE response was analysed by immunoblotting (WB) assay, using both excretory/secretory products (ESPs) and crude extract (CE) of A. pegreffii larvae. The results were compared with those achieved by the conventional immunological method for Anisakis allergy (ie, immunoCAP). Among the 110 subjects, 28 showed IgE positivity with both WB and iCAP methods; 13 proved IgE reactivity, in WB assay, to ESP antigens of A. pegreffii, here provisionally indicated as Ani s 1-like, Ani s 7-like, Ani s 13-like; only 15 sera have shown IgE-WB reaction to Ani s 7-like and Ani s 13-like. iCAP and WB exhibited a high concordance value (κ=1.00) when iCAP value was <0.35 (negative result) and >50.0 (positive result). In the sera samples recorded as positive to Anisakis allergy, Ani s 1-like was responsible for 46.4% of the sensitivity, while Ani s 7-like and Ani s 13-like for 100%. They could be considered as major antigens in the diagnosis of allergic anisakiasis caused by A. pegreffii. © 2017 John Wiley & Sons Ltd.

Development of a real-time PCR assay for rapid detection and quantification of Photobacterium damselae subsp. piscicida in fish tissues.

PubMed

Carraro, R; Dalla Rovere, G; Ferraresso, S; Carraro, L; Franch, R; Toffan, A; Pascoli, F; Patarnello, T; Bargelloni, L

2018-02-01

The availability of a rapid and accurate method for the diagnosis of Photobacterium damselae subsp. piscicida (Phdp), able to discriminate its strictly correlated subsp. damselae (Phdd), formally known as Vibrio damsela, is essential for managing fish pasteurellosis outbreaks in farmed fish. A single-step, high-sensitivity real-time PCR assay for simultaneous detection and quantification of P. damselae was designed targeting partial of the sequence of the bamB gene and tested for specificity and sensitivity on laboratory-generated samples as well as on experimentally infected seabream tissue samples. With a limit of detection (LOD) of one copy in pure bacterial DNA, the sensitivity was higher than all methods previously reported. Validation in target and non-target bacterial species proved the assay was able to discriminate Phdd-Phdp subspecies from diverse hosts/geographical origins and between non-target species. In addition, two SNPs in the target amplicon region determine two distinctive qPCR dissociation curves distinguishing between Phdp-Phdd. This is the first time that a molecular method for P. damselae diagnosis combines detection, quantification and subspecies identification in one step. The assay holds the potential to improve the knowledge of infection dynamics and the development of better strategies to control an important fish disease. © 2017 John Wiley & Sons Ltd.

Multiple Chemical Sensitivity (MCS) - Scientific and Public-Health Aspects

PubMed Central

Schwenk, Michael

2004-01-01

Multiple Chemical Sensitivity (MCS) is a phenomenon which the ENT-doctor should be familiar with. It has its roots in the description of a syndrome in 1987. A worker spilled chemicals at his workplace and from then on he reacted highly sensitive to chemicals. Today, there are many people who explain their complaints with self-suspected MCS. Various pathopysiological models have been proposed, including toxicological, immunological or behaviorial models. But no-one could be proved so far. Since controlled provocation tests have also provided unclear results, an increasing number of doctors assumes today, that MCS reflects a psychic condition. In 1996, an expert team of the WHO has suggested the renaming of MCS to "idiopathic environmental illness" (IEI). However, other doctors still assume a chemical cause. Since there are neither straightforward diagnostic methods to proof MCS, nor reliable therapeutic concepts, treatment of MCS-patients is usually difficult. The MCS-debate (somatic vs psychic causes) seems to reflect the dilemma of the medical profession today, that somatic disorders of known origin can be well treated, whereas the increasing number of psychosomatic/ somatoform disorders is often resistant to medical help. The ENT-doctor should pay attention to changes of the nasal mucous membrane, nasal resistance and the sense of smell. Moreover he should know about the peculiarities of MCS-patients. The manuscript describes the present knowledge and state of discussion with special regard to the situation in Germany. PMID:22073047

Sensitive detection of pyoverdine with an electrochemical sensor based on electrochemically generated graphene functionalized with gold nanoparticles.

PubMed

Gandouzi, Islem; Tertis, Mihaela; Cernat, Andreea; Bakhrouf, Amina; Coros, Maria; Pruneanu, Stela; Cristea, Cecilia

2018-04-01

The design and development of an electrochemical sensor for the sensitive and selective determination of pyoverdine, a virulence factor secreted by Pseudomonas aeruginosa, bacteria involved in nosocomial infections is presented in this work. The presence of pyoverdine in water and body fluids samples can be directly linked to the presence of the Pseudomonas bacteria, thus being a nontoxic and low cost marker for the detection of water pollution as well as for the biological contamination of other media. The sensor was elaborated using layer-by-layer technique for the deposition of a graphene‑gold nanoparticles composite film on the graphite-based screen printed electrode, from aqueous suspension. Under optimal conditions, the electrochemical signal corresponding to the pyoverdine oxidation process was proportional to its concentration, showing a wide linear range from 1 to 100μmolL -1 and a detection limit of 0.33μmolL -1 . This sensor discriminate with satisfactory recoveries the target analyte in different real matrices and also exhibited low response to other interfering species, proving that this technique is promising for medical and environmental applications. In addition, the proposed nanocomposite platform presented good reproducibility, high and long term stability, the sensitivity for pyoverdine remain unchanged after being stored at 4°C for four weeks. Copyright © 2017 Elsevier B.V. All rights reserved.

A short-term swimming speed alteration test with nauplii of Artemia franciscana.

PubMed

Morgana, Silvia; Estévez-Calvar, Noelia; Gambardella, Chiara; Faimali, Marco; Garaventa, Francesca

2018-01-01

The presence of toxicant needs to be assessed within short time in order to effectively protect the aquatic environment from serious threat. Based on the observation that at high temperatures aquatic organisms become more vulnerable to stressors than those maintained at room temperature, a new test was developed. The proposed bioassay consisted in the evaluation of the swimming speed alteration (SSA) of nauplii of Artemia franciscana incubated at 39°C (± 1) for 6h, using a Swimming Behavior Recorder system (SBR). A comparative ecotoxicological study between the 6h SSA test and the 24h mortality test was carried out in order to validate the new method in terms of sensitivity by means of EC 50 values. The bioassay was applied to screen different toxicants: K 2 Cr 2 O 7 , Cu(SO 4 ) 2 , NaClO, SDS and Sertraline hydrochloride. The EC 50s calculated for the short-term SSA test and those of the mortality test showed comparable values. For all toxicants, the 6h SSA test was proved to be as sensitive as the 24h mortality test. The method developed in this study is the first temperature-based toxicity test with nauplii of Artemia franciscana and it represents an attractive assay in ecotoxicology because of its convenience in terms of time and costs, feasibility and sensitivity. Copyright © 2017 Elsevier Inc. All rights reserved.

Adequacy of surface analytical tools for studying the tribology of ceramics

NASA Technical Reports Server (NTRS)

Sliney, H. E.

1986-01-01

Surface analytical tools are very beneficial in tribological studies of ceramics. Traditional methods of optical microscopy, XRD, XRF, and SEM should be combined with newer surface sensitive techniques especially AES and XPS. ISS and SIMS can also be useful in providing additional compositon details. Tunneling microscopy and electron energy loss spectroscopy are less known techniques that may also prove useful.

Recent developments at JPL in the application of digital image processing techniques to astronomical images

NASA Technical Reports Server (NTRS)

Lorre, J. J.; Lynn, D. J.; Benton, W. D.

1976-01-01

Several techniques of a digital image-processing nature are illustrated which have proved useful in visual analysis of astronomical pictorial data. Processed digital scans of photographic plates of Stephans Quintet and NGC 4151 are used as examples to show how faint nebulosity is enhanced by high-pass filtering, how foreground stars are suppressed by linear interpolation, and how relative color differences between two images recorded on plates with different spectral sensitivities can be revealed by generating ratio images. Analyses are outlined which are intended to compensate partially for the blurring effects of the atmosphere on images of Stephans Quintet and to obtain more detailed information about Saturn's ring structure from low- and high-resolution scans of the planet and its ring system. The employment of a correlation picture to determine the tilt angle of an average spectral line in a low-quality spectrum is demonstrated for a section of the spectrum of Uranus.

Determination of sex origin of meat and meat products on the DNA basis: a review.

PubMed

Gokulakrishnan, Palanisamy; Kumar, Rajiv Ranjan; Sharma, Brahm Deo; Mendiratta, Sanjod Kumar; Malav, Omprakash; Sharma, Deepak

2015-01-01

Sex determination of domestic animal's meat is of potential value in meat authentication and quality control studies. Methods aiming at determining the sex origin of meat may be based either on the analysis of hormone or on the analysis of nucleic acids. At the present time, sex determination of meat and meat products based on hormone analysis employ gas chromatography-mass spectrometry (GC-MS), high-performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC-MS/MS), and enzyme-linked immunosorbent assay (ELISA). Most of the hormone-based methods proved to be highly specific and sensitive but were not performed on a regular basis for meat sexing due to the technical limitations or the expensive equipments required. On the other hand, the most common methodology to determine the sex of meat is unquestionably traditional polymerase chain reaction (PCR) that involves gel electrophoresis of DNA amplicons. This review is intended to provide an overview of the DNA-based methods for sex determination of meat and meat products.

A credit policy approach in a two-warehouse inventory model for deteriorating items with price- and stock-dependent demand under partial backlogging

NASA Astrophysics Data System (ADS)

Panda, Gobinda Chandra; Khan, Md. Al-Amin; Shaikh, Ali Akbar

2018-04-01

Advertisement of the product is an important factor in inventory analysis. Also, price and stock have an important role to attract more customers in the competitive business situations. Trade credit policy is another important role in inventory analysis. We have combined these three factors together in a two-warehouse inventory model and represented it mathematically. In addition, we have added deteriorating factor of our proposed problem with price- and stock-dependent demand under partial backlogged shortage and solved. The frequency of advertisement is considered constant for a year in this paper. The proposed model is highly nonlinear in nature. Due to highly nonlinearity, we could not find the closed form solution. In this paper, trade credit facility is taken in the perspective of retailer, and all the possible cases and subcases of the model are discussed and solved using lingo 10.0 software. The results of sensitivity analysis prove the effectiveness of the proposed model.

Structural Deterministic Safety Factors Selection Criteria and Verification

NASA Technical Reports Server (NTRS)

Verderaime, V.

1992-01-01

Though current deterministic safety factors are arbitrarily and unaccountably specified, its ratio is rooted in resistive and applied stress probability distributions. This study approached the deterministic method from a probabilistic concept leading to a more systematic and coherent philosophy and criterion for designing more uniform and reliable high-performance structures. The deterministic method was noted to consist of three safety factors: a standard deviation multiplier of the applied stress distribution; a K-factor for the A- or B-basis material ultimate stress; and the conventional safety factor to ensure that the applied stress does not operate in the inelastic zone of metallic materials. The conventional safety factor is specifically defined as the ratio of ultimate-to-yield stresses. A deterministic safety index of the combined safety factors was derived from which the corresponding reliability proved the deterministic method is not reliability sensitive. The bases for selecting safety factors are presented and verification requirements are discussed. The suggested deterministic approach is applicable to all NASA, DOD, and commercial high-performance structures under static stresses.

Improvement of up-converting phosphor technology-based biosensor

NASA Astrophysics Data System (ADS)

Xie, Chengke; Huang, Lihua; Zhang, Youbao; Guo, Xiaoxian; Qu, Jianfeng; Huang, Huijie

2008-12-01

A novel biosensor based on up-converting phosphor technology (UPT) was developed several years ago. It is a kind of optical biosensor using up-converting phosphor (UCP) particles as the biological marker. From then on, some improvements have been made for this UPT-based biosensor. The primary aspects of the improvement lie in the control system. On one hand, the hardware of the control system has been optimized, including replacing two single chip microcomputers (SCM) with only one, the optimal design of the keyboard interface circuit and the liquid crystal module (LCM) control circuit et al.. These result in lower power consumption and higher reliability. On the other hand, a novel signal processing algorithm is proposed in this paper, which can improve the automation and operating simplicity of the UPT-based biosensor. It has proved to have high sensitivity (~ng/ml), high stability and good repeatability (CV<5%), which is better than the former system. It can meet the need of some various applications such as rapid immunoassay, chemical and biological detection and so on.

Effects of sterilisation by high-energy radiation on biomedical poly-(epsilon-caprolactone)/hydroxyapatite composites.

PubMed

Di Foggia, Michele; Corda, Ugo; Plescia, Elena; Taddei, Paola; Torreggiani, Armida

2010-06-01

The effects of a high energy sterilization treatment on poly-epsilon-caprolactone/carbonated hydroxyapatite composites have been investigated. Poly-epsilon-caprolactone is a biodegradable polymer used as long-term bioresorbable scaffold for bone tissue engineering and carbonated hydroxyapatite is a bioactive material able to promote bone growth. The composites were gamma-irradiated in air or under nitrogen atmosphere with doses ranging from 10 to 50 kGy (i.e. to a value higher than that recommended for sterilization). The effects of the irradiation treatment were evaluated by vibrational spectroscopy (IR and Raman spectroscopies) coupled to thermal analysis (Differential Scanning Calorimetry and Thermogravimetry) and Electron Paramagnetic Resonance spectroscopy. Irradiation with the doses required for sterilization induced acceptable structural changes and damaging effects: only a very slight fragmentation of the polymeric chains and some defects in the inorganic component were observed. Moreover, the radiation sensitivity of the composites proved almost the same under the two different atmospheres.

Soil fauna and soil microflora as possible indicators of soil pollution.

PubMed

Eijsackers, H

1983-09-01

Research on biological indicators of soil pollution is hampered by soil variability and temporal and spatial fluctuations of numbers of soil animals. These characters on the other hand promote a high biological diversity in the soil. A high diversity combined with persistent soil pollutants increases the chance to select good indicators. However research on these topics is still limited. Examples of specific indicators are the changed arthropod species patterns due to pesticide influence and the changed soil enzyme activity under the influence of specific heavy metals. Another approach is to look for organisms that give a general indication of soil pollution. In this respect the earthworm species Allolobophora caliginosa proved to be sensitive for different types of manure especially pig manure with copper, for sewage sludge, for municipal waste compost and for fly ash. A third way of indication is by organisms accumulating pollutants. For some heavy metals (Cd, Zn), earthworms are very efficient accumulators. More research is needed especially on the specific relation between biological responses and abiotic soil characteristics.

A novel spectrofluorimetric method for the assay of pseudoephedrine hydrochloride in pharmaceutical formulations via derivatization with 4-chloro-7-nitrobenzofurazan.

PubMed

El-Didamony, Akram M; Gouda, Ayman A

2011-01-01

A new highly sensitive and specific spectrofluorimetric method has been developed to determine a sympathomimetic drug pseudoephedrine hydrochloride. The present method was based on derivatization with 4-chloro-7-nitrobenzofurazan in phosphate buffer at pH 7.8 to produce a highly fluorescent product which was measured at 532 nm (excitation at 475 nm). Under the optimized conditions a linear relationship and good correlation was found between the fluorescence intensity and pseudoephedrine hydrochloride concentration in the range of 0.5-5 µg mL(-1). The proposed method was successfully applied to the assay of pseudoephedrine hydrochloride in commercial pharmaceutical formulations with good accuracy and precision and without interferences from common additives. Statistical comparison of the results with a well-established method showed excellent agreement and proved that there was no significant difference in the accuracy and precision. The stoichiometry of the reaction was determined and the reaction pathway was postulated. Copyright © 2010 John Wiley & Sons, Ltd.

Identification of hare meat by a species-specific marker of mitochondrial origin.

PubMed

Santos, Cristina G; Melo, Vitor S; Amaral, Joana S; Estevinho, Letícia; Oliveira, M Beatriz P P; Mafra, Isabel

2012-03-01

Meat species identification in food has gained increasing interest in recent years due to public health, economic and legal concerns. Following the consumer trend towards high quality products, game meat has earned much attention. The aim of the present work was to develop a DNA-based technique able to identify hare meat. Mitochondrial cytochrome b gene was used to design species-specific primers for hare detection. The new primers proved to be highly specific to Lepus species, allowing the detection of 0.01% of hare meat in pork meat by polymerase chain reaction (PCR). A real-time PCR assay with the new intercalating EvaGreen dye was further proposed as a specific and fast tool for hare identification with increased sensitivity (1pg) compared to end-point PCR (10pg). It can be concluded that the proposed new primers can be used by both species-specific end-point PCR or real-time PCR to accurately authenticate hare meat. Copyright © 2011 Elsevier Ltd. All rights reserved.

Increasing the resource of high load compression springs

NASA Astrophysics Data System (ADS)

Zemlyanushnova, N. Y.; Zemlyanushnov, N. A.

2017-10-01

Valve springs of VAZ automobiles’ engines are manufactured by using a new method. The decrease of dispersion of operating load in experimental springs compared to serial ones has been proved. The springs have passed a stress cycling test. With the new method having been used, it has been proved that the resource of high load springs working at high loading speed with coils collision has increased up to 60%.

Studies on the optical and photoelectric properties of anthocyanin and chlorophyll as natural co-sensitizers in dye sensitized solar cell

NASA Astrophysics Data System (ADS)

Nan, Hui; Shen, He-Ping; Wang, Gang; Xie, Shou-Dong; Yang, Gui-Jun; Lin, Hong

2017-11-01

Anthocyanin and Chlorophyll extracted from Troll flower and Cypress leaf respectively are used as natural sensitizers in dye sensitized solar cells (DSCs), with their optical and electrochemical properties investigated. UV-Vis absorption measurement showed that the mixture of two dyes enabled an enhanced and wider absorption in the wavelength range of 300 nm-700 nm compared to each single dye. FTIR results proved that anthocyanin is chemically adsorbed onto the TiO2 film, while it is physical adsorption for chlorophyll. The energy level offsets on the TiO2/dye/electrolyte interface for each dye and the dye mixture with different ratios were calculated from the electrochemical analysis, which affect the electron injection and dye regeneration efficiencies. The optimized ratio of the two dyes in the mixture was found to be ∼2:5, inducing both sufficient charge transfer driving force and minimal energy loss. By incorporating this mixture into the solar cell as co-adsorbing sensitizer, the photovoltaic performance was prominently improved compared with the single dye sensitization system.

Sensitivity enhancement in swept-source optical coherence tomography by parametric balanced detector and amplifier

PubMed Central

Kang, Jiqiang; Wei, Xiaoming; Li, Bowen; Wang, Xie; Yu, Luoqin; Tan, Sisi; Jinata, Chandra; Wong, Kenneth K. Y.

2016-01-01

We proposed a sensitivity enhancement method of the interference-based signal detection approach and applied it on a swept-source optical coherence tomography (SS-OCT) system through all-fiber optical parametric amplifier (FOPA) and parametric balanced detector (BD). The parametric BD was realized by combining the signal and phase conjugated idler band that was newly-generated through FOPA, and specifically by superimposing these two bands at a photodetector. The sensitivity enhancement by FOPA and parametric BD in SS-OCT were demonstrated experimentally. The results show that SS-OCT with FOPA and SS-OCT with parametric BD can provide more than 9 dB and 12 dB sensitivity improvement, respectively, when compared with the conventional SS-OCT in a spectral bandwidth spanning over 76 nm. To further verify and elaborate their sensitivity enhancement, a bio-sample imaging experiment was conducted on loach eyes by conventional SS-OCT setup, SS-OCT with FOPA and parametric BD at different illumination power levels. All these results proved that using FOPA and parametric BD could improve the sensitivity significantly in SS-OCT systems. PMID:27446655

Exploring the engines of molecular outflows

NASA Astrophysics Data System (ADS)

Testi, Leonardo

1995-03-01

Water vapour masers and CO outflows are well known to be associated with the youngest phases of evolution of massive stellar objects. Nevertheless, up to now there is a lack of high resolution multiwavelength study of the regions containing these objects. Using the VLA, the CSO and the TIRGO equipped with the new Near-Infrared (NIR) camera ARNICA, we have begun a systematic study of water maser/CO outflow regions. These new high resolution and high sensitivity data have proved to be very useful in probing the star formation activity and the connection between infrared and radio sources. Here we report the results obtained in a preliminary sub- sample of objects. The NIR data showed that both the maser spots and the large- scale outflows tend to be associated to the most embedded and probably younger sources of the infrared clusters. Infrared emission lines observed with narrow band filters show the presence of jet-like structures in most of the sources observed. Water masers, jet-like and Herbig-Haro-like infrared structures, and CO outflows enable to probe ejection phenomena at all spacial scales ranging from 0.01 to 1 parsec.

[Simultaneous determination of 7 arsenic species in chicken muscle and chicken liver with high performance liquid chromatography-inductively coupled plasma mass spectrometry].

PubMed

Yang, Lijun; Hu, Qiaoru; Guo, Wei; Liu, Yumin; Song, Xiaohua; Zhang, Pengcheng

2011-05-01

A method for the simultaneous determination of 7 arsenic species was developed with high performance liquid chromatography and inductively coupled plasma mass spectrometry (HPLC-ICP-MS). The sample was extracted with artificial gastric juice. The HPLC separation was performed on an anion analytical column utilizing a gradient elution program of ammonium carbonate and water as the mobile phase. Identification and quantification were achieved by ICP-MS. Good linearities of 7 arsenic species were observed in the range from 1 microg/kg to 50 microg/kg with the correlation coefficients greater than 0.999. The average recoveries of 7 arsenic species spiked at the three levels of 1, 2 and 10 microg/kg ranged from 84.3% to 106.6% with the relative standard deviations of 1.4%-4.2%. The quantification limits of 7 arsenic species were 1 microg/kg. The method was proved to be good reproducibility, high sensitivity and simple preprocessing. This method is suitable for the simultaneous determination of 7 arsenic species in chicken muscle and chicken liver.

Ag Nanoparticles-Modified 3D Graphene Foam for Binder-Free Electrodes of Electrochemical Sensors.

PubMed

Han, Tao; Jin, Jianli; Wang, Congxu; Sun, Youyi; Zhang, Yinghe; Liu, Yaqing

2017-02-16

Ag nanoparticles-modified 3D graphene foam was synthesized through a one-step in-situ approach and then directly applied as the electrode of an electrochemical sensor. The composite foam electrode exhibited electrocatalytic activity towards Hg(II) oxidation with high limit of detection and sensitivity of 0.11 μM and 8.0 μA/μM, respectively. Moreover, the composite foam electrode for the sensor exhibited high cycling stability, long-term durability and reproducibility. These results were attributed to the unique porous structure of the composite foam electrode, which enabled the surface of Ag nanoparticles modified reduced graphene oxide (Ag NPs modified rGO) foam to become highly accessible to the metal ion and provided more void volume for the reaction with metal ion. This work not only proved that the composite foam has great potential application in heavy metal ions sensors, but also provided a facile method of gram scale synthesis 3D electrode materials based on rGO foam and other electrical active materials for various applications.

Ag Nanoparticles-Modified 3D Graphene Foam for Binder-Free Electrodes of Electrochemical Sensors

PubMed Central

Han, Tao; Jin, Jianli; Wang, Congxu; Sun, Youyi; Zhang, Yinghe; Liu, Yaqing

2017-01-01

Ag nanoparticles-modified 3D graphene foam was synthesized through a one-step in-situ approach and then directly applied as the electrode of an electrochemical sensor. The composite foam electrode exhibited electrocatalytic activity towards Hg(II) oxidation with high limit of detection and sensitivity of 0.11 µM and 8.0 µA/µM, respectively. Moreover, the composite foam electrode for the sensor exhibited high cycling stability, long-term durability and reproducibility. These results were attributed to the unique porous structure of the composite foam electrode, which enabled the surface of Ag nanoparticles modified reduced graphene oxide (Ag NPs modified rGO) foam to become highly accessible to the metal ion and provided more void volume for the reaction with metal ion. This work not only proved that the composite foam has great potential application in heavy metal ions sensors, but also provided a facile method of gram scale synthesis 3D electrode materials based on rGO foam and other electrical active materials for various applications. PMID:28336878

Robust, Sensitive, and Automated Phosphopeptide Enrichment Optimized for Low Sample Amounts Applied to Primary Hippocampal Neurons.

PubMed

Post, Harm; Penning, Renske; Fitzpatrick, Martin A; Garrigues, Luc B; Wu, W; MacGillavry, Harold D; Hoogenraad, Casper C; Heck, Albert J R; Altelaar, A F Maarten

2017-02-03

Because of the low stoichiometry of protein phosphorylation, targeted enrichment prior to LC-MS/MS analysis is still essential. The trend in phosphoproteome analysis is shifting toward an increasing number of biological replicates per experiment, ideally starting from very low sample amounts, placing new demands on enrichment protocols to make them less labor-intensive, more sensitive, and less prone to variability. Here we assessed an automated enrichment protocol using Fe(III)-IMAC cartridges on an AssayMAP Bravo platform to meet these demands. The automated Fe(III)-IMAC-based enrichment workflow proved to be more effective when compared to a TiO 2 -based enrichment using the same platform and a manual Ti(IV)-IMAC-based enrichment workflow. As initial samples, a dilution series of both human HeLa cell and primary rat hippocampal neuron lysates was used, going down to 0.1 μg of peptide starting material. The optimized workflow proved to be efficient, sensitive, and reproducible, identifying, localizing, and quantifying thousands of phosphosites from just micrograms of starting material. To further test the automated workflow in genuine biological applications, we monitored EGF-induced signaling in hippocampal neurons, starting with only 200 000 primary cells, resulting in ∼50 μg of protein material. This revealed a comprehensive phosphoproteome, showing regulation of multiple members of the MAPK pathway and reduced phosphorylation status of two glutamate receptors involved in synaptic plasticity.

Detection limits of the strip test and PCR for genetically modified corn in Brazil.

PubMed

Nascimento, V E; Von Pinho, É V R; Von Pinho, R G; do Nascimento, A D

2012-08-16

Brazilian legislation establishes a labeling limit for products that contain more than 1% material from genetically modified organisms (GMOs). We assessed the sensitivity of the lateral flow strip test in detection of the GMO corn varieties Bt11 and MON810 and the specificity and sensitivity of PCR techniques for their detection. For the strip test, the GMO seeds were mixed with conventional seeds at levels of 0.2, 0.4 and 0.8% for Bt11, and 0.4, 0.8 and 1.6% for MON810. Three different methodologies were assessed and whole seeds, their endosperm and embryonic axis were used. For the PCR technique, the GMO seeds of each of the two varieties were mixed with conventional seeds at levels of 20, 10, 5, 2, 1, and 0.5%. The seeds were ground and the DNA extracted. For detection of the GMO material, specific primers were used for MON810 and Bt11 and maize zein as an endogenous control. The sensitivity of the strip test varied for both maize varieties and methodologies. The test was positive for Bt11 only at 0.8%, in contrast with the detection limit of 0.4% indicated by the manufacturer. In the multiplex PCR, the primers proved to be specific for the different varieties. These varieties were detected in samples with one GMO seed in 100. Thus, this technique proved to be efficient in detecting contaminations equal to or greater than 1%.

A global sensitivity analysis of crop virtual water content

NASA Astrophysics Data System (ADS)

Tamea, S.; Tuninetti, M.; D'Odorico, P.; Laio, F.; Ridolfi, L.

2015-12-01

The concepts of virtual water and water footprint are becoming widely used in the scientific literature and they are proving their usefulness in a number of multidisciplinary contexts. With such growing interest a measure of data reliability (and uncertainty) is becoming pressing but, as of today, assessments of data sensitivity to model parameters, performed at the global scale, are not known. This contribution aims at filling this gap. Starting point of this study is the evaluation of the green and blue virtual water content (VWC) of four staple crops (i.e. wheat, rice, maize, and soybean) at a global high resolution scale. In each grid cell, the crop VWC is given by the ratio between the total crop evapotranspiration over the growing season and the crop actual yield, where evapotranspiration is determined with a detailed daily soil water balance and actual yield is estimated using country-based data, adjusted to account for spatial variability. The model provides estimates of the VWC at a 5x5 arc minutes and it improves on previous works by using the newest available data and including multi-cropping practices in the evaluation. The model is then used as the basis for a sensitivity analysis, in order to evaluate the role of model parameters in affecting the VWC and to understand how uncertainties in input data propagate and impact the VWC accounting. In each cell, small changes are exerted to one parameter at a time, and a sensitivity index is determined as the ratio between the relative change of VWC and the relative change of the input parameter with respect to its reference value. At the global scale, VWC is found to be most sensitive to the planting date, with a positive (direct) or negative (inverse) sensitivity index depending on the typical season of crop planting date. VWC is also markedly dependent on the length of the growing period, with an increase in length always producing an increase of VWC, but with higher spatial variability for rice than for other crops. The sensitivity to the reference evapotranspiration is highly variable with the considered crop and ranges from positive values (for soybean), to negative values (for rice and maize) and near-zero values for wheat. This variability reflects the different yield response factors of crops, which expresses their tolerance to water stress.

Ultrafast electrochemical preparation of graphene/CoS nanosheet counter electrodes for efficient dye-sensitized solar cells

DOE PAGES

Zhu, Chongyang; Zhu, Yimei; Min, Huihua; ...

2015-10-05

Utilizing inexpensive, high-efficiency counter electrodes (CEs) to replace the traditional platinum counterparts in dye-sensitized solar cells (DSSCs) is worthwhile. In this paper, we detail how we synchronously prepared composite CEs of CoS nanosheet arrays and reduced graphene oxide (rGO) layers for the first time via a low temperature, ultrafast one-step electrochemical strategy. With this approach, the whole fabrication process of the composite CEs was only a small percentage of the average time (~15 hours) using other methods. The DSSC assembled with the rGO–CoS composite CE achieved an enhanced power conversion efficiency (PCE) of 8.34%, which is dramatically higher than 6.27%more » of pure CoS CE-based DSSC and even exceeds 7.50% of Pt CE-based DSSC. The outstanding PCE breakthrough is undoubtedly attributed to the enhancement in electrocatalytic ability of the rGO–CoS composite CE due to the incorporation of highly conducting rGO layers and the GO layers-induced growth of CoS nanosheet arrays with higher density and larger surface area. Therefore, lower charge-transfer resistance and higher exchange current density can be achieved as corroborated by the electrochemical impedance spectra (EIS) and Tafel polarization curves (TPCs). As a result, further experiments also proved that the electrochemical strategy exhibited its universality of fabricating other graphene-enhanced chalcogenide functional composite films.« less

Simulation on a car interior aerodynamic noise control based on statistical energy analysis

NASA Astrophysics Data System (ADS)

Chen, Xin; Wang, Dengfeng; Ma, Zhengdong

2012-09-01

How to simulate interior aerodynamic noise accurately is an important question of a car interior noise reduction. The unsteady aerodynamic pressure on body surfaces is proved to be the key effect factor of car interior aerodynamic noise control in high frequency on high speed. In this paper, a detail statistical energy analysis (SEA) model is built. And the vibra-acoustic power inputs are loaded on the model for the valid result of car interior noise analysis. The model is the solid foundation for further optimization on car interior noise control. After the most sensitive subsystems for the power contribution to car interior noise are pointed by SEA comprehensive analysis, the sound pressure level of car interior aerodynamic noise can be reduced by improving their sound and damping characteristics. The further vehicle testing results show that it is available to improve the interior acoustic performance by using detailed SEA model, which comprised by more than 80 subsystems, with the unsteady aerodynamic pressure calculation on body surfaces and the materials improvement of sound/damping properties. It is able to acquire more than 2 dB reduction on the central frequency in the spectrum over 800 Hz. The proposed optimization method can be looked as a reference of car interior aerodynamic noise control by the detail SEA model integrated unsteady computational fluid dynamics (CFD) and sensitivity analysis of acoustic contribution.

Development of highly sensitive cell-based AKT kinase ELISA for monitoring PI3K beta activity and compound efficacy.

PubMed

Yanamandra, Mahesh; Kole, Labanyamoy; Giri, Archana; Mitra, Sayan

2017-01-01

Phosphatidylinositol-3 kinase (PI3K) pathway regulates multiple cellular functions involving cell survival, growth, motility proliferation, apoptosis, and adhesion. These are deregulated in various diseases such as cancer, atherosclerosis, and inflammation. PI3Ks phosphorylate phosphatidylinositol 4,5-biphosphate (PIP2) yielding phosphatidylinositol 3, 4, 5 triphosphate (PIP3) which in turn activate AKT kinase (serine/threonine kinase), the central enzyme in regulation of metabolic functions. Due to their implications in disease pathophysiology, PI3K/AKT inhibitors became attractive targets for pharmaceutical industries. In order to assess the functional response generated by PI3K inhibitors, an appropriate cell-based screening system is essential in any screening cascade. Here we report the development of highly sensitive in-vitro cell-based kinase ELISA which quantifies the phosphorylated AKT kinase (serine 473) and total AKT kinase directly within the cells upon compound treatment. PI3Kβ overexpressing NIH3T3 cells stimulated by lysophosphatidic acid was used for PI3K/Akt pathway activation. Assay performance reliability and robustness were determined by percentage coefficient of variation (%CV) and Z factor which demonstrated an excellent agreement with assay guidelines. This 96-well plate medium throughput assay methodology was used to screen novel molecules and proved a commendable tool to study the mechanism of action property and target engagement of novel PI3K inhibitors in drug discovery.

Rapid identification of tomato Sw-5 resistance-breaking isolates of Tomato spotted wilt virus using high resolution melting and TaqMan SNP Genotyping assays as allelic discrimination techniques.

PubMed

di Rienzo, Valentina; Bubici, Giovanni; Montemurro, Cinzia; Cillo, Fabrizio

2018-01-01

In tomato, resistance to Tomato spotted wilt virus (TSWV) is conferred by the dominant gene, designated Sw-5. Virulent Sw-5 resistance breaking (SRB) mutants of TSWV have been reported on Sw-5 tomato cultivars. Two different PCR-based allelic discrimination techniques, namely Custom TaqMan™ SNP Genotyping and high-resolution melting (HRM) assays, were developed and compared for their ability to distinguish between avirulent (Sw-5 non-infecting, SNI) and SRB biotypes. TaqMan assays proved to be more sensitive (threshold of detection in a range of 50-70 TSWV RNA copies) and more reliable than HRM, assigning 25 TSWV isolates to their correct genotype with an accuracy of 100%. Moreover, the TaqMan SNP assays were further improved developing a rapid and simple protocol that included crude leaf extraction for RNA template preparations. On the other hand, HRM assays showed higher levels of sensitivity than TaqMan when used to co-detect both biotypes in different artificial mixtures. These diagnostic assays contributed to gain preliminary information on the epidemiology of TSWV isolates in open field conditions. In fact, the presented data suggest that SRB isolates are present as stable populations established year round, persisting on both winter (globe artichoke) and summer (tomato) crops, in the same cultivated areas of Southern Italy.

A semi-automated magnetic capture probe based DNA extraction and real-time PCR method applied in the Swedish surveillance of Echinococcus multilocularis in red fox (Vulpes vulpes) faecal samples.

PubMed

Isaksson, Mats; Hagström, Åsa; Armua-Fernandez, Maria Teresa; Wahlström, Helene; Ågren, Erik Olof; Miller, Andrea; Holmberg, Anders; Lukacs, Morten; Casulli, Adriano; Deplazes, Peter; Juremalm, Mikael

2014-12-19

Following the first finding of Echinococcus multilocularis in Sweden in 2011, 2985 red foxes (Vulpes vulpes) were analysed by the segmental sedimentation and counting technique. This is a labour intensive method and requires handling of the whole carcass of the fox, resulting in a costly analysis. In an effort to reduce the cost of labour and sample handling, an alternative method has been developed. The method is sensitive and partially automated for detection of E. multilocularis in faecal samples. The method has been used in the Swedish E. multilocularis monitoring program for 2012-2013 on more than 2000 faecal samples. We describe a new semi-automated magnetic capture probe DNA extraction method and real time hydrolysis probe polymerase chain reaction assay (MC-PCR) for the detection of E. multilocularis DNA in faecal samples from red fox. The diagnostic sensitivity was determined by validating the new method against the sedimentation and counting technique in fox samples collected in Switzerland where E. multilocularis is highly endemic. Of 177 foxes analysed by the sedimentation and counting technique, E. multilocularis was detected in 93 animals. Eighty-two (88%, 95% C.I 79.8-93.9) of these were positive in the MC-PCR. In foxes with more than 100 worms, the MC-PCR was positive in 44 out of 46 (95.7%) cases. The two MC-PCR negative samples originated from foxes with only immature E. multilocularis worms. In foxes with 100 worms or less, (n = 47), 38 (80.9%) were positive in the MC-PCR. The diagnostic specificity of the MC-PCR was evaluated using fox scats collected within the Swedish screening. Of 2158 samples analysed, two were positive. This implies that the specificity is at least 99.9% (C.I. = 99.7-100). The MC-PCR proved to have a high sensitivity and a very high specificity. The test is partially automated but also possible to perform manually if desired. The test is well suited for nationwide E. multilocularis surveillance programs where sampling of fox scats is done to reduce the costs for sampling and where a test with a high sensitivity and a very high specificity is needed.

Additive effects of clofibric acid and pyruvate dehydrogenase kinase isoenzyme 4 (PDK4) deficiency on hepatic steatosis in mice fed a high-saturated fat diet

PubMed Central

Hwang, Byounghoon; Wu, Pengfei; Harris, Robert A.

2012-01-01

SUMMARY Although improving glucose metabolism by inhibition of pyruvate dehydrogenase kinase 4 (PDK4) might prove beneficial in the treatment of type 2 diabetes or diet-induced obesity, it might induce detrimental effects by inhibiting fatty acid oxidation. PPARα agonists are often used to treat dyslipidemia in patients, especially in type 2 diabetes. Combinational treatment with a PDK4 inhibitor and PPARα agonists may prove beneficial. However, PPARα agonists may be less effective in the presence of a PDK4 inhibitor because PPARα agonists induce PDK4 expression. In the present study, the effects of clofibric acid, a PPARα agonist, on blood and liver lipids were determined in wild type and PDK4 knockout mice fed a high fat diet. As expected, treatment of wild type mice with clofibric acid resulted in less body weight gain, smaller epididymal fat pads, greater insulin sensitivity, and lower levels of serum and liver triacylglycerol. Surprisingly, rather than decreasing the effectiveness of clofibric acid, PDK4 deficiency enhanced the beneficial effects of clofibric acid on hepatic steatosis, lowered blood glucose levels, and did not prevent the positive effects of clofibric acid on serum triacylglycerols and free fatty acids. The metabolic effects of clofibric acid are therefore independent of the induction of PDK4 expression. The additive beneficial effects on hepatic steatosis may be due to induction of increased capacity for fatty acid oxidation and partial uncoupling of oxidative phosphorylation by clofibric acid and a reduction in the capacity for fatty acid synthesis by PDK4 deficiency. PMID:22429297

Hearing loss in the developing world: evaluating the iPhone mobile device as a screening tool.

PubMed

Peer, S; Fagan, J J

2015-01-01

Developing countries have the world's highest prevalence of hearing loss, and hearing screening programmes are scarce. Mobile devices such as smartphones have potential for audiometric testing. To evaluate the uHear app using an Apple iPhone as a possible hearing screening tool in the developing world, and to determine accuracy of certain hearing thresholds that could prove useful in early detection of hearing loss for high-risk populations in resource-poor communities. This was a quasi-experimental study design. Participants recruited from the Otolaryngology Clinic, Groote Schuur Hospital, Cape Town, South Africa, completed a uHear test in three settings--waiting room (WR), quiet roon (QR) and soundproof room (SR). Thresholds were compared with formal audiograms. Twenty-five patients were tested (50 ears). The uHear test detected moderate or worse hearing loss (pure-tone average (PTA) > 40 dB accurately with a sensitivity of 100% in all three environments. Specificity was 88% (SR), 73% (QR) and 68% (WR). Its was highly accurate in detecting high-frequency hearing loss (2 000, 4 000, 6 000 Hz) in the QR and SR with 'good' and 'very good' kappa values, showing statistical significance (p < 0.05). It was moderately accurate in low-frequency hearing loss (250, 500, 1 000 Hz) in the SR, and poor in the QR and WR. Using the iPhone, uHear is a feasible screening test to rule out significant hearing loss (PTA > 40 dB). It is highly sensitive for detecting threshold changes at high frequencies, making it reasonably well suited to detect presbycusis and ototoxic hearing loss from HIV, tuberculosis therapy and chemotherapy. Portability and ease of use make it appropriate to use in developing world communities that lack screening programmes.

Horizontal silicon nanowires for surface-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Gebavi, Hrvoje; Ristić, Davor; Baran, Nikola; Mikac, Lara; Mohaček-Grošev, Vlasta; Gotić, Marijan; Šikić, Mile; Ivanda, Mile

2018-01-01

The main purpose of this paper is to focus on details of the fabrication process of horizontally and vertically oriented silicon nanowires (SiNWs) substrates for the application of surface-enhanced Raman spectroscopy (SERS). The fabrication process is based on the vapor-liquid-solid method and electroless-assisted chemical etching, which, as the major benefit, resulting in the development of economical, easy-to-prepare SERS substrates. Furthermore, we examined the fabrication of Au coated Ag nanoparticles (NPs) on the SiNWs substrates in such a way as to diminish the influence of silver NPs corrosion, which, in turn, enhanced the SERS time stability, thus allowing for wider commercial applications. The substances on which high SERS sensitivity was proved are rhodamine (R6G) and 4-mercaptobenzoic acid (MBA), with the detection limits of 10-8 M and 10-6 M, respectively.

The Electrocardiogram and Ischemic Heart Disease in Aircraft Pilots

PubMed Central

Manning, G. W.

1965-01-01

A review of the Royal Canadian Air Force electrocardiographic (ECG) program for selection of aircrew and detection of coronary disease in trained aircrew is presented. Twenty reported cases of death due to coronary disease in pilots while at the controls of an aircraft are reviewed. The use of routine electrocardiography in the selection of aircrew has proved to be of considerable value, particularly in view of the high cost of training. The ECG continues to be our most sensitive means of detecting asymptomatic coronary disease in aircrew personnel. It is apparent that from both the military and commercial standpoint the incidence of aircraft accidents due to coronary disease is extremely small. This is due in large part to the careful medical supervision of flying personnel including the routine use of electrocardiography in the assessment of flying fitness of aircrew. PMID:14323657

Multiplex hydrolysis probe real-time PCR for simultaneous detection of hepatitis A virus and hepatitis E virus.

PubMed

Qiu, Feng; Cao, Jingyuan; Su, Qiudong; Yi, Yao; Bi, Shengli

2014-05-30

Detection of hepatitis viral infections has traditionally relied on the circulating antibody test using the enzyme-linked immunosorbent assay. However, multiplex real-time PCR has been increasingly used for a variety of viral nucleic acid detections and has proven to be superior to traditional methods. Hepatitis A virus (HAV) and hepatitis E virus (HEV) are the major causes of acute hepatitis worldwide; both HAV and HEV infection are a main public health problem. In the present study, a one-step multiplex reverse transcriptase quantitative polymerase chain reaction assay using hydrolysis probes was developed for simultaneously detecting HAV and HEV. This novel detection system proved specific to the target viruses, to be highly sensitive and to be applicable to clinical sera samples, making it useful for rapid, accurate and feasible identification of HAV and HEV.

High resolution in-beam γ-ray spectroscopy

NASA Astrophysics Data System (ADS)

Kern, J.; Dousse, J.-Cl.; Gasser, M.; Perny, B.; Rhême, Ch.

1985-01-01

An in-beam curved crystal facility has been installed at the SIN variable energy cyclotron. Using the (110) planes of a 3.0 mm thick quartz lamina bent at 3.15 m, diffraction peaks typically 6 arcsec wide (FWHM) are obtained. The energy resolution is thus, for instance, 110 eV at 170 keV in 3rd order. Due to a sophisticated detector system and heavy shielding, the sensitivity of the instrument is quite good. The facility proves quite useful in (p,xnγ) reaction studies whenever the γ-ray spectrum is very complex, e.g. in the study of odd-odd deformed nuclei. Complicated multiplets appearing in the 176Yb(p,3nγ)174Lu spectrum could be successfully resolved. From the results we derive that the g-factors of the 142 d, Jπ=6- isomer, take anomalous values.

Emission FTIR analyses of thin microscopic patches of jet fuel residues deposited on heated metal surfaces

NASA Technical Reports Server (NTRS)

Lauer, J. L.; Vogel, P.

1986-01-01

The relationship of fuel stability to fuel composition and the development of mechanisms for deposit formation were investigated. Fuel deposits reduce heat transfer efficiency and increase resistance to fuel flow and are highly detrimental to aircraft performance. Infrared emission Fourier transform spectroscopy was chosen as the primary method of analysis because it was sensitive enough to be used in-situ on tiny patches of monolayers or of only a few molecular layers of deposits which generally proved completely insoluble in any nondestructive solvents. Deposits of four base fuels were compared; dodecane, a dodecane/tetralin blend, commercial Jet A fuel, and a broadened-properties jet fuel particularly rich in polynuclear aromatics. Every fuel in turn was provided with and without small additions of such additives as thiophene, furan, pyrrole, and copper and iron naphthenates.

Implosion-driven technique to create fast shockwaves in high-density gas

NASA Astrophysics Data System (ADS)

Serge, Matthew; Loiseau, Jason; Huneault, Justin; Szirti, Daniel; Higgins, Andrew; Tanguay, Vincent

2012-03-01

Pressurized tubes surrounded by either one or two layers (separated by a secondary tube) of sensitized nitromethane and encased in a thick-walled tube (the tamper) were imploded. The distance between the detonation wave in the explosive and shock wave in the innermost tube were measured (the standoff). A simple model based on hoop stress and acoustic interactions between the tubing was developed and used to predict the standoff distance. At low initial pressures (on the order of 7MPa), results indicate that the secondary tube and two layers of explosive did not prove to significantly increase the standoff. However, at higher pressures (on the order of 10 MPa), standoff was noticeably greater when the secondary tube was inserted between the pressurized tube and the tamper. The measured values are in reasonable agreement with the predictions of the model.

Magneto-Sensitive Adsorbents Modified by Functional Nitrogen-Containing Groups

NASA Astrophysics Data System (ADS)

Melnyk, Inna V.; Gdula, Karolina; Dąbrowski, Andrzej; Zub, Yuriy L.

2016-02-01

In order to obtain amino-functionalized silica materials with magnetic core, one-step synthesis was carried out. Several materials, differ in number and structure of amino groups, were synthesized on the basis of sol-gel method. The synthesized materials were examined by several analytical techniques. The presence and content of amino groups were measured by using Diffuse Reflectance Infrared Fourier Transform (DRIFT) spectroscopy and acid-base titration, respectively. Specific surface areas were measured by nitrogen/adsorption desorption isotherms. It was proved that sol-gel approach leads to obtain materials with high content of amino groups built into their surfaces (in the range 1.6-2.7 mmol/g). As-obtained materials were tested as potential adsorbents for copper(II) ions. The received maximum adsorption capacities were in the range 0.4-0.7 mmol/g.

Land use in the northern Coachella Valley

NASA Technical Reports Server (NTRS)

Bale, J. B.; Bowden, L. W.

1973-01-01

Satellite imagery has proved to have great utility for monitoring land use change and as a data source for regional planning. In California, open space desert resources are under severe pressure to serve as a source for recreational gratification to individuals living in the heavily populated southern coastal plain. Concern for these sensitive arid environments has been expressed by both federal and state agencies. The northern half of the Coachella Valley has historically served as a focal point for weekend recreational activity and second homes. Since demand in this area has remained high, land use change from rural to urban residential has been occurring continuously since 1968. This area of rapid change is an ideal site to illustrate the utility of satellite imagery as a data source for planning information, and has served as the areal focus of this investigation.

Evaluation of the Nurses’ Job Satisfaction, and Its Association with Their Moral Sensitivities and Well-being

PubMed Central

Jaafarpour, Molouk; Khani, Ali

2012-01-01

Background and Aim Several researchers have described the nurses’ work as stressful and that the incidence of the occupational stress-related burnout in the profession was high. The aim of this study was to establish the relationship between the nurses’ satisfaction, their psychosocial work environment, the levels of their reported moral sensitivities and their well - being in Iran. Material and Methods This descriptive-correlation study was performed at the ILAM general hospitals, IR, during the year 2011. The research instruments which were used were the Psychosocial Work Environment (PWE), the Moral Sensitivity (MS) and the well-being profile of the nurses. A sample of 120 Registered Nurses (RN) were enrolled in the study by using a simple random sampling method. The descriptive statistics and the Pearson’s correlation test were performed by using SPSS. Result The relationship of the nurses’ satisfaction and their psychosocial work environment was moderate (M=106.5, SD= 7.2) . The nurses’ moral sensitivity was moderate (M=112.3, SD= 11.2).This study found that there were significant correlations between the PWE factors score and the MS subscale (P< 0.05, p<0.01). In addition, significant correlations were found between the nurses’ well-being and the PWE factors (P< 0.05, p<0.01). Discussion and Conclusion These findings proved that the nurses perceived their PWE as stressful. The supporting nurses may have a positive effect on their perceptions of well-being. The attending nurses reported less physical symptoms, reduced anxiety and fewer feelings of not being in control. PMID:23373046

Molecular Evolution of the Tissue-nonspecific Alkaline Phosphatase Allows Prediction and Validation of Missense Mutations Responsible for Hypophosphatasia*

PubMed Central

Silvent, Jérémie; Gasse, Barbara; Mornet, Etienne; Sire, Jean-Yves

2014-01-01

ALPL encodes the tissue nonspecific alkaline phosphatase (TNSALP), which removes phosphate groups from various substrates. Its function is essential for bone and tooth mineralization. In humans, ALPL mutations lead to hypophosphatasia, a genetic disorder characterized by defective bone and/or tooth mineralization. To date, 275 ALPL mutations have been reported to cause hypophosphatasia, of which 204 were simple missense mutations. Molecular evolutionary analysis has proved to be an efficient method to highlight residues important for the protein function and to predict or validate sensitive positions for genetic disease. Here we analyzed 58 mammalian TNSALP to identify amino acids unchanged, or only substituted by residues sharing similar properties, through 220 millions years of mammalian evolution. We found 469 sensitive positions of the 524 residues of human TNSALP, which indicates a highly constrained protein. Any substitution occurring at one of these positions is predicted to lead to hypophosphatasia. We tested the 204 missense mutations resulting in hypophosphatasia against our predictive chart, and validated 99% of them. Most sensitive positions were located in functionally important regions of TNSALP (active site, homodimeric interface, crown domain, calcium site, …). However, some important positions are located in regions, the structure and/or biological function of which are still unknown. Our chart of sensitive positions in human TNSALP (i) enables to validate or invalidate at low cost any ALPL mutation, which would be suspected to be responsible for hypophosphatasia, by contrast with time consuming and expensive functional tests, and (ii) displays higher predictive power than in silico models of prediction. PMID:25023282

Silver halide sensitized gelatin process effects in holographic lenses recorded on Slavich PFG-01 plates

NASA Astrophysics Data System (ADS)

Collados, Maria Victoria; Arias, Isabel; García, Ana; Atencia, Jesús; Quintanilla, Manuel

2003-02-01

In this work we study the feasibility of using silver halide sensitized gelatin based on PFG-01 (Slavich) emulsions to construct uniaxial compound lenses. This processing is able to introduce variations in the thickness and refractive index of the emulsion. We prove that these changes are not sufficient to provide the observed variations in Bragg conditions in the reconstruction and that a shear-type effect must exist to explain the performance of processed emulsions. We study the characteristics of a compound lens, obtaining acceptable image quality, good resolution, and the typical field limitation of volume holographic elements.

Field camera measurements of gradient and shim impulse responses using frequency sweeps.

PubMed

Vannesjo, S Johanna; Dietrich, Benjamin E; Pavan, Matteo; Brunner, David O; Wilm, Bertram J; Barmet, Christoph; Pruessmann, Klaas P

2014-08-01

Applications of dynamic shimming require high field fidelity, and characterizing the shim field dynamics is therefore necessary. Modeling the system as linear and time-invariant, the purpose of this work was to measure the impulse response function with optimal sensitivity. Frequency-swept pulses as inputs are analyzed theoretically, showing that the sweep speed is a key factor for the measurement sensitivity. By adjusting the sweep speed it is possible to achieve any prescribed noise profile in the measured system response. Impulse response functions were obtained for the third-order shim system of a 7 Tesla whole-body MR scanner. Measurements of the shim fields were done with a dynamic field camera, yielding also cross-term responses. The measured shim impulse response functions revealed system characteristics such as response bandwidth, eddy currents and specific resonances, possibly of mechanical origin. Field predictions based on the shim characterization were shown to agree well with directly measured fields, also in the cross-terms. Frequency sweeps provide a flexible tool for shim or gradient system characterization. This may prove useful for applications involving dynamic shimming by yielding accurate estimates of the shim fields and a basis for setting shim pre-emphasis. Copyright © 2013 Wiley Periodicals, Inc.

Enantiospecific Detection of Chiral Nanosamples Using Photoinduced Force

NASA Astrophysics Data System (ADS)

Kamandi, Mohammad; Albooyeh, Mohammad; Guclu, Caner; Veysi, Mehdi; Zeng, Jinwei; Wickramasinghe, Kumar; Capolino, Filippo

2017-12-01

We propose a high-resolution microscopy technique for enantiospecific detection of chiral samples down to sub-100-nm size based on force measurement. We delve into the differential photoinduced optical force Δ F exerted on an achiral probe in the vicinity of a chiral sample when left and right circularly polarized beams separately excite the sample-probe interactive system. We analytically prove that Δ F is entangled with the enantiomer type of the sample enabling enantiospecific detection of chiral inclusions. Moreover, we demonstrate that Δ F is linearly dependent on both the chiral response of the sample and the electric response of the tip and is inversely related to the quartic power of probe-sample distance. We provide physical insight into the transfer of optical activity from the chiral sample to the achiral tip based on a rigorous analytical approach. We support our theoretical achievements by several numerical examples highlighting the potential application of the derived analytic properties. Lastly, we demonstrate the sensitivity of our method to enantiospecify nanoscale chiral samples with chirality parameter on the order of 0.01 and discuss how the sensitivity of our proposed technique can be further improved.

Testing cognitive function in elderly populations: the PROSPER study. PROspective Study of Pravastatin in the Elderly at Risk.

PubMed

Houx, P J; Shepherd, J; Blauw, G-J; Murphy, M B; Ford, I; Bollen, E L; Buckley, B; Stott, D J; Jukema, W; Hyland, M; Gaw, A; Norrie, J; Kamper, A M; Perry, I J; MacFarlane, P W; Meinders, A Edo; Sweeney, B J; Packard, C J; Twomey, C; Cobbe, S M; Westendorp, R G

2002-10-01

For large scale follow up studies with non-demented patients in which cognition is an endpoint, there is a need for short, inexpensive, sensitive, and reliable neuropsychological tests that are suitable for repeated measurements. The commonly used Mini-Mental-State-Examination fulfils only the first two requirements. In the PROspective Study of Pravastatin in the Elderly at Risk (PROSPER), 5804 elderly subjects aged 70 to 82 years were examined using a learning test (memory), a coding test (general speed), and a short version of the Stroop test (attention). Data presented here were collected at dual baseline, before randomisation for active treatment. The tests proved to be reliable (with test/retest reliabilities ranging from acceptable (r=0.63) to high (r=0.88) and sensitive to detect small differences in subjects from different age categories. All tests showed significant practice effects: performance increased from the first measurement to the first follow up after two weeks. Normative data are provided that can be used for one time neuropsychological testing as well as for assessing individual and group change. Methods for analysing cognitive change are proposed.

The miniaturized Raman system and detection of traces of life in halite from the Atacama Desert: some considerations for the search for life signatures on Mars.

PubMed

Vítek, Petr; Jehlička, Jan; Edwards, Howell G M; Hutchinson, Ian; Ascaso, Carmen; Wierzchos, Jacek

2012-12-01

Raman spectroscopy is being adopted as a nondestructive instrumentation for the robotic exploration of Mars to search for traces of life in the geological record. Here, miniaturized Raman spectrometers of two different types equipped with 532 and 785 nm lasers for excitation, respectively, were compared for the detection of microbial biomarkers in natural halite from the hyperarid region of the Atacama Desert. Measurements were performed directly on the rock as well as on the homogenized, powdered samples prepared from this material-the effects of this sample preparation and the excitation wavelength employed in the analysis are compared and discussed. From these results, 532 nm excitation was found to be superior for the analysis of powdered specimens due to its high sensitivity toward carotenoids and hence a higher capability for their detection at relatively low concentration in bulk powdered specimens. For the same reason, this wavelength was a better choice for the detection of carotenoids in direct measurements made on the rock samples. The 785 nm excitation wavelength, in contrast, proved to be more sensitive toward the detection of scytonemin.

The Unfolding MD Simulations of Cyclophilin: Analyzed by Surface Contact Networks and Their Associated Metrics

PubMed Central

Roy, Sourav; Basu, Sankar; Dasgupta, Dipak; Bhattacharyya, Dhananjay; Banerjee, Rahul

2015-01-01

Currently, considerable interest exists with regard to the dissociation of close packed aminoacids within proteins, in the course of unfolding, which could result in either wet or dry moltenglobules. The progressive disjuncture of residues constituting the hydrophobic core ofcyclophilin from L. donovani (LdCyp) has been studied during the thermal unfolding of the molecule, by molecular dynamics simulations. LdCyp has been represented as a surface contactnetwork (SCN) based on the surface complementarity (Sm) of interacting residues within themolecular interior. The application of Sm to side chain packing within proteins make it a very sensitive indicator of subtle perturbations in packing, in the thermal unfolding of the protein. Network based metrics have been defined to track the sequential changes in the disintegration ofthe SCN spanning the hydrophobic core of LdCyp and these metrics prove to be highly sensitive compared to traditional metrics in indicating the increased conformational (and dynamical) flexibility in the network. These metrics have been applied to suggest criteria distinguishing DMG, WMG and transition state ensembles and to identify key residues involved in crucial conformational/topological events during the unfolding process. PMID:26545107

Usefulness of Four Different Echinococcus granulosus Recombinant Antigens for Serodiagnosis of Unilocular Hydatid Disease (UHD) and Postsurgical Follow-Up of Patients Treated for UHD▿

PubMed Central

Hernández-González, Ana; Muro, Antonio; Barrera, Inmaculada; Ramos, Guillermo; Orduña, Antonio; Siles-Lucas, Mar

2008-01-01

Four different recombinant antigens derived from Echinococcus granulosus, designated B1t, B2t, E14t, and C317, were tested with enzyme-linked immunosorbent assays (ELISAs) for the detection of specific immunoglobulin G (IgG) in patients with unilocular hydatid disease (UHD). The results were compared to those obtained with hydatid fluid and were subjected to receiver operator characteristic analysis. The diagnostic performance of the above-listed proteins was defined with respect to their specificity, sensitivity, and predictive values (PV); the influence of cyst location; and usefulness in the follow-up of surgical treatment for UHD and in the determination of whether or not patients have been surgically cured of UHD. The best diagnostic results were obtained with the anti-B2t IgG ELISA, with 91.2% sensitivity, 93% specificity, and high positive and negative PV (89.4 and 94.2, respectively). In addition, this diagnostic tool proved to be useful for the follow-up of surgically treated UHD patients. The anti-B2t IgG ELISA may find an application in the serodiagnosis of UHD in clinical laboratories. PMID:17989342

Bolometer detection of magnetic resonances in nanoscaled objects

NASA Astrophysics Data System (ADS)

Rod, Irina; Meckenstock, Ralf; Zähres, Horst; Derricks, Christian; Mushenok, Fedor; Reckers, Nathalie; Kijamnajsuk, Puchong; Wiedwald, Ulf; Farle, Michael

2014-10-01

We report on a nanoscaled thermocouple (ThC) as a temperature sensor of a highly sensitive bolometer for probing the dissipative damping of spin dynamics in nanosized Permalloy (Py) stripes. The Au-Pd ThC based device is fabricated by standard electron beam lithography on a 200 nm silicon nitride membrane to minimize heat dissipation through the substrate. We show that this thermal sensor allows not only measurements of the temperature change on the order of a few mK due to the uniform resonant microwave (MW) absorption by the Py stripe but also detection of standing spin waves of different mode numbers. Using a 3D finite element method, we estimate the absorbed MW power by the stripe in resonance and prove the necessity of using substrates with an extremely low heat dissipation like a silicon nitride membrane for successful thermal detection. The voltage responsivity and the noise equivalent power for the ThC-based bolometer are equal to 15 V W-1 and 3 nW Hz-1/2, respectively. The ThC device offers a magnetic resonance response of 1 nV/(μB W) corresponding to a sensitivity of 109 spins and a temperature resolution of 300 μK under vacuum conditions.

Sample size for positive and negative predictive value in diagnostic research using case–control designs

PubMed Central

Steinberg, David M.; Fine, Jason; Chappell, Rick

2009-01-01

Important properties of diagnostic methods are their sensitivity, specificity, and positive and negative predictive values (PPV and NPV). These methods are typically assessed via case–control samples, which include one cohort of cases known to have the disease and a second control cohort of disease-free subjects. Such studies give direct estimates of sensitivity and specificity but only indirect estimates of PPV and NPV, which also depend on the disease prevalence in the tested population. The motivating example arises in assay testing, where usage is contemplated in populations with known prevalences. Further instances include biomarker development, where subjects are selected from a population with known prevalence and assessment of PPV and NPV is crucial, and the assessment of diagnostic imaging procedures for rare diseases, where case–control studies may be the only feasible designs. We develop formulas for optimal allocation of the sample between the case and control cohorts and for computing sample size when the goal of the study is to prove that the test procedure exceeds pre-stated bounds for PPV and/or NPV. Surprisingly, the optimal sampling schemes for many purposes are highly unbalanced, even when information is desired on both PPV and NPV. PMID:18556677

Strict lymphotropism of Epstein-Barr virus during acute infectious mononucleosis in nonimmunocompromised individuals.

PubMed

Karajannis, M A; Hummel, M; Anagnostopoulos, I; Stein, H

1997-04-15

Previous investigations of exfoliated oropharyngeal cells from individuals suffering from infectious mononucleosis (IM) suggested that the oropharyngeal epithelia are the primary target and also the site of life-long persistence of the Epstein-Barr virus (EBV). This concept was widely accepted. However, the investigation of histological sections with more sensitive EBV detection techniques has drawn this concept into doubt since EBV proved to be constantly absent in normal epithelial cells. To elucidate the discrepancy, throat washings and peripheral mononuclear blood cells from 16 patients suffering from IM were investigated for EBV-DNA and EBV gene products employing highly sensitive in situ hybridization, immunocytochemistry, and polymerase chain reaction. Although all patients exhibited latently infected B lymphocytes in peripheral blood, samples of exfoliated oropharyngeal cells were constantly EBV-negative with the exception of three cases. In these cases, the patients additionally suffered from purulent ulcerating tonsillitis, EBV-infected B cells, but no EBV-infected epithelial cells were detectable. These findings support the view that recirculating lymphocytes of B-cell origin, but not epithelial cells are the initial target of EBV during primary infection and that B cells also represent the site of life-long viral persistence.

A naked-eye colorimetric "PCR developer"

NASA Astrophysics Data System (ADS)

Valentini, Paola; Pompa, Pier Paolo

2016-04-01

Despite several advances in molecular biology and diagnostics, Polymerase Chain Reaction (PCR) is currently the gold standard for nucleic acids amplification and detection, due to its versatility, low-cost and universality, with estimated <10 billion reactions per year and a worldwide market of several billion dollars/year. Nevertheless, PCR still relies on the laborious, time-consuming, and multi-step gel electrophoresis-based detection, which includes gel casting, electrophoretic run, gel staining, and gel visualization. In this work, we propose a "PCR developer", namely a universal one-step, one-tube method, based on controlled aggregation of gold nanoparticles (AuNPs), to detect PCR products by naked eye in few minutes, with no need for any instrumentation. We demonstrated the specificity and sensitivity of the PCR developer on different model targets, suitable for a qualitative detection in real-world diagnostics (i.e., gene rearrangements, genetically modified organisms, and pathogens). The PCR developer proved to be highly specific and ultra-sensitive, discriminating down to few copies of HIV viral DNA, diluted in an excess of interfering human genomic DNA, which is a clinically relevant viral load. Hence, it could be a valuable tool for both academic research and clinical applications.

Enhanced sensitivity and multiplexing with 2D LC/MRM-MS and labeled standards for deeper and more comprehensive protein quantitation.

PubMed

Percy, Andrew J; Simon, Romain; Chambers, Andrew G; Borchers, Christoph H

2014-06-25

Mass spectrometry (MS)-based protein quantitation is increasingly being employed to verify candidate protein biomarkers. Multiple or selected reaction monitoring-mass spectrometry (MRM-MS or SRM-MS) with isotopically labeled internal standards has proven to be a successful approach in that regard, but has yet to reach its full potential in terms of multiplexing and sensitivity. Here, we report the development of a new MRM method for the quantitation of 253 disease-associated proteins (represented by 625 interference-free peptides) in 13 LC fractions. This 2D RPLC/MRM-MS approach extends the depth and breadth of the assay by 2 orders of magnitude over pre-fractionation-free assays, with 31 proteins below 10 ng/mL and 41 proteins above 10 ng/mL now quantifiable. Standard flow rates are used in both chromatographic dimensions, and up-front depletion or antibody-based enrichment is not required. The LC separations utilize high and low pH conditions, with the former employing an ammonium hydroxide-based eluent, instead of the conventional ammonium formate, resulting in improved LC column lifetime and performance. The high sensitivity (determined concentration range: 15 mg/mL to 452 pg/mL) and robustness afforded by this method makes the full MRM panel, or subsets thereof, useful for the verification of disease-associated plasma protein biomarkers in patient samples. The described research extends the breadth and depth of protein quantitation in undepleted and non-enriched human plasma by employing standard-flow 2D RPLC/MRM-MS in conjunction with a complex mixture of isotopically labeled peptide standards. The proteins quantified are mainly putative biomarkers of non-communicable (i.e., non-infectious) disease (e.g., cardiovascular or cancer), which require pre-clinical verification and validation before clinical implementation. Based on the enhanced sensitivity and multiplexing, this quantitative plasma proteomic method should prove useful in future candidate biomarker verification studies. Copyright © 2014 Elsevier B.V. All rights reserved.

Geospatial approach for assessment of biophysical vulnerability to agricultural drought and its intra-seasonal variations.

PubMed

Sehgal, Vinay Kumar; Dhakar, Rajkumar

2016-03-01

The study presents a methodology to assess and map agricultural drought vulnerability during main kharif crop season at local scale and compare its intra-seasonal variations. A conceptual model of vulnerability based on variables of exposure, sensitivity, and adaptive capacity was adopted, and spatial datasets of key biophysical factors contributing to vulnerability were generated using remote sensing and GIS for Rajasthan State of India. Hazard exposure was based on frequency and intensity of gridded standardized precipitation index (SPI). Agricultural sensitivity was based on soil water holding capacity as well as on frequency and intensity of normalized difference vegetation index (NDVI)-derived trend adjusted vegetation condition index (VCITadj). Percent irrigated area was used as a measure of adaptive capacity. Agricultural drought vulnerability was derived separately for early, mid, late, and whole kharif seasons by composting rating of factors using linear weighting scheme and pairwise comparison of multi-criteria evaluation. The regions showing very low to extreme rating of hazard exposure, drought sensitivity, and agricultural vulnerability were identified at all four time scales. The results indicate that high to extreme vulnerability occurs in more than 50% of net sown area in the state and such areas mostly occur in western, central, and southern parts. The higher vulnerability is on account of non-irrigated croplands, moderate to low water holding capacity of sandy soils, resulting in higher sensitivity, and located in regions with high probability of rainfall deficiency. The mid and late season vulnerability has been found to be much higher than that during early and whole season. Significant correlation of vulnerability rating with food grain productivity, drought recurrence period, crop area damaged in year 2009 and socioeconomic indicator of human development index (HDI) proves the general soundness of methodology. Replication of this methodology in other areas is expected to lead to better preparedness and mitigation-oriented management of droughts.

Serodiagnosis of Echinococcus spp. Infection: Explorative Selection of Diagnostic Antigens by Peptide Microarray

PubMed Central

List, Claudia; Qi, Weihong; Maag, Eva; Gottstein, Bruno; Müller, Norbert; Felger, Ingrid

2010-01-01

Background Production of native antigens for serodiagnosis of helminthic infections is laborious and hampered by batch-to-batch variation. For serodiagnosis of echinococcosis, especially cystic disease, most screening tests rely on crude or purified Echinococcus granulosus hydatid cyst fluid. To resolve limitations associated with native antigens in serological tests, the use of standardized and highly pure antigens produced by chemical synthesis offers considerable advantages, provided appropriate diagnostic sensitivity and specificity is achieved. Methodology/Principal Findings Making use of the growing collection of genomic and proteomic data, we applied a set of bioinformatic selection criteria to a collection of protein sequences including conceptually translated nucleotide sequence data of two related tapeworms, Echinococcus multilocularis and Echinococcus granulosus. Our approach targeted alpha-helical coiled-coils and intrinsically unstructured regions of parasite proteins potentially exposed to the host immune system. From 6 proteins of E. multilocularis and 5 proteins of E. granulosus, 45 peptides between 24 and 30 amino acids in length were designed. These peptides were chemically synthesized, spotted on microarrays and screened for reactivity with sera from infected humans. Peptides reacting above the cut-off were validated in enzyme-linked immunosorbent assays (ELISA). Peptides identified failed to differentiate between E. multilocularis and E. granulosus infection. The peptide performing best reached 57% sensitivity and 94% specificity. This candidate derived from Echinococcus multilocularis antigen B8/1 and showed strong reactivity to sera from patients infected either with E. multilocularis or E. granulosus. Conclusions/Significance This study provides proof of principle for the discovery of diagnostically relevant peptides by bioinformatic selection complemented with screening on a high-throughput microarray platform. Our data showed that a single peptide cannot provide sufficient diagnostic sensitivity whereas pooling several peptide antigens improved sensitivity; thus combinations of several peptides may lead the way to new diagnostic tests that replace, or at least complement conventional immunodiagnosis of echinococcosis. Our strategy could prove useful for diagnostic developments in other pathogens. PMID:20689813

Surface nanodroplets for highly efficient liquid-liquid microextraction

NASA Astrophysics Data System (ADS)

Li, Miaosi; Lu, Ziyang; Yu, Haitao; Zhang, Xuehua

2016-11-01

Nanoscale droplets on a substrate are an essential element for a wide range of applications, such as laboratory-on-chip devices, simple and highly efficient miniaturized reactors for concentrating products, high-throughput single-bacteria or single-biomolecular analysis, encapsulation, and high-resolution imaging techniques. The solvent exchange process is a simple bottom-up approach for producing droplets at solid-liquid interfaces that are only several tens to hundreds of nanometers in height, or a few femtoliters in volume Oil nanodroplets can be produced on a substrate by solvent exchange in which a good solvent of oil is displaced by a poor solvent. Our previous work has significantly advanced understanding of the principle of solvent exchange, and the droplet size can be well-controlled by several parameters, including flow rates, flow geometry, gravitational effect and composition of solutions. In this work, we studied the microextraction effect of surface nanodroplets. Oil nanodroplets have been demonstrated to provide highly-efficient liquid-liquid microextraction of hydrophobic solute in a highly diluted solution. This effect proved the feasibility of nanodroplets as a platform for preconcentrating compounds for in situ highly sensitive microanalysis without further separation. Also the long lifetime and temporal stability of surface nanodroplets allow for some long-term extraction process and extraction without addition of stabilisers.

Experimental investigation of edge hardening and edge cracking sensitivity of burr-free parts

NASA Astrophysics Data System (ADS)

Senn, Sergei; Liewald, Mathias

2018-05-01

This experimental study is focused on characterisation of edge hardening of sheet metal and remaining formability of differently prepared cutted edges. Edge cracking sensitivity of counter cutted, shear cutted, recutted and water-jet cutted components are compared and evaluated. Subsequently, edge hardening and hole expansion ratio were correlated for material HC420 LA with sheet thickness of t = 2 mm. As other studies show, the cutting edge surface quality influences the hole expansion ratio: a high clear cut surface increases formability of cutting edges, whereas micro cracks and rough surfaces result into a large fracture surface, which impact remaining formability noticeably. Thus, cutting edges with lower edge hardening behaviour in conjunction with a higher clear cut surface exhibit higher hole expansion ratios. Counter cutting and the recutting do show a similar effect on edge hardening. Using the hole expansion test, it was possible to prove that counter cutted components show a significantly lower edge cracking sensitivity in comparison to conventionally shear cutted components. The hole expansion ratio of counter cutted specimens looks balanced and is comparable to the hole expansion ratio measured from specimens with recutted or water jet cutted edges. The significant difference of the investigated cutting processes is characterized by size of clear cutting area. This area of recutted edges emerges larger than the area of counter cutted specimens, which evidently leads to an increased hole expansion ratio of recutted specimens compared to conventionally shear cutted ones. However, it is important to note that the hole expansion ratio of counter cutted and recutted specimens appear fairly balanced, but counter cutted samples indeed can be produced burr-free. Using counter cutting technology, it is possible to produce burr free surfaces with high edge formability.

Molecular diagnosis of lyssaviruses and sequence comparison of Australian bat lyssavirus samples.

PubMed

Foord, A J; Heine, H G; Pritchard, L I; Lunt, R A; Newberry, K M; Rootes, C L; Boyle, D B

2006-07-01

To evaluate and implement molecular diagnostic tests for the detection of lyssaviruses in Australia. A published hemi-nested reverse transcriptase polymerase chain reaction (RT-PCR) for the detection of all lyssavirus genotypes was modified to a fully nested RT-PCR format and compared with the original assay. TaqMan assays for the detection of Australian bat lyssavirus (ABLV) were compared with both the nested and hemi-nested RT-PCR assays. The sequences of RT-PCR products were determined to assess sequence variations of the target region (nucleocapsid gene) in samples of ABLV originating from different regions. The nested RT-PCR assay was highly analytically specific, and at least as analytically sensitive as the hemi-nested assay. The TaqMan assays were highly analytically specific and more analytically sensitive than either RT-PCR assay, with a detection level of approximately 10 genome equivalents per microl. Sequence of the first 544 nucleotides of the nucleocapsid protein coding sequence was obtained from all samples of ABLV received at Australian Animal Health Laboratory during the study period. The nested RT-PCR provided a means for molecular diagnosis of all tested genotypes of lyssavirus including classical rabies virus and Australian bat lyssavirus. The published TaqMan assay proved to be superior to the RT-PCR assays for the detection of ABLV in terms of analytical sensitivity. The TaqMan assay would also be faster and cross contamination is less likely. Nucleotide sequence analyses of samples of ABLV from a wide geographical range in Australia demonstrated the conserved nature of this region of the genome and therefore the suitability of this region for molecular diagnosis.

pH-sensitive micelles self-assembled from polymer brush (PAE-g-cholesterol)-b-PEG-b-(PAE-g-cholesterol) for anticancer drug delivery and controlled release

PubMed Central

Huang, Xiangxuan; Liao, Wenbo; Zhang, Gang; Kang, Shimin; Zhang, Can Yang

2017-01-01

A novel amphiphilic pH-sensitive triblock polymer brush (poly(β-amino esters)-g-cholesterol)-b-poly(ethylene glycol)-b-(poly(β-amino esters)-g-cholesterol) ((PAE-g-Chol)-b-PEG-b-(PAE-g-Chol)) was designed and synthesized successfully through a three-step reaction, and their self-assembled polymeric micelles were used as hydrophobic anticancer drug delivery carriers to realize effectively controlled release. The critical micelle concentrations were 6.8 μg/mL, 12.6 μg/mL, 17.4 μg/mL, and 26.6 μg/mL at pH values of 7.4, 6.5, 6.0, and 5.0, respectively. The trend of critical micelle concentrations indicated that the polymer had high stability that could prolong the circulation time in the body. The hydrodynamic diameter and zeta potential of the polymeric micelles were influenced significantly by the pH values. As pH decreased from 7.4 to 5.0, the particle size and zeta potential increased from 205.4 nm to 285.7 nm and from +12.7 mV to +47.0 mV, respectively. The pKb of the polymer was confirmed to be approximately 6.5 by the acid–base titration method. The results showed that the polymer had sharp pH-sensitivity because of the protonation of the amino groups, resulting in transformation of the PAE segment from hydrophobic to hydrophilic. Doxorubicin-loaded polymeric micelles were prepared with a high loading content (20%) and entrapment efficiency (60%) using the dialysis method. The in vitro results demonstrated that drug release rate and cumulative release were obviously dependent on pH values. Furthermore, the drug release mechanism was also controlled by the pH values. The polymer had barely any cytotoxicity, whereas the doxorubicin-loaded system showed high toxicity for HepG2 cells as free drugs. All the results proved that the pH-sensitive triblock polymer brush and its self-assembled micelle might be a potential delivery carrier for anticancer drugs with sustained release. PMID:28356738

pH-sensitive micelles self-assembled from polymer brush (PAE-g-cholesterol)-b-PEG-b-(PAE-g-cholesterol) for anticancer drug delivery and controlled release.

PubMed

Huang, Xiangxuan; Liao, Wenbo; Zhang, Gang; Kang, Shimin; Zhang, Can Yang

2017-01-01

A novel amphiphilic pH-sensitive triblock polymer brush (poly(β-amino esters)- g -cholesterol)- b -poly(ethylene glycol)- b -(poly(β-amino esters)- g -cholesterol) ((PAE- g -Chol)- b -PEG- b -(PAE- g -Chol)) was designed and synthesized successfully through a three-step reaction, and their self-assembled polymeric micelles were used as hydrophobic anticancer drug delivery carriers to realize effectively controlled release. The critical micelle concentrations were 6.8 μg/mL, 12.6 μg/mL, 17.4 μg/mL, and 26.6 μg/mL at pH values of 7.4, 6.5, 6.0, and 5.0, respectively. The trend of critical micelle concentrations indicated that the polymer had high stability that could prolong the circulation time in the body. The hydrodynamic diameter and zeta potential of the polymeric micelles were influenced significantly by the pH values. As pH decreased from 7.4 to 5.0, the particle size and zeta potential increased from 205.4 nm to 285.7 nm and from +12.7 mV to +47.0 mV, respectively. The p K b of the polymer was confirmed to be approximately 6.5 by the acid-base titration method. The results showed that the polymer had sharp pH-sensitivity because of the protonation of the amino groups, resulting in transformation of the PAE segment from hydrophobic to hydrophilic. Doxorubicin-loaded polymeric micelles were prepared with a high loading content (20%) and entrapment efficiency (60%) using the dialysis method. The in vitro results demonstrated that drug release rate and cumulative release were obviously dependent on pH values. Furthermore, the drug release mechanism was also controlled by the pH values. The polymer had barely any cytotoxicity, whereas the doxorubicin-loaded system showed high toxicity for HepG2 cells as free drugs. All the results proved that the pH-sensitive triblock polymer brush and its self-assembled micelle might be a potential delivery carrier for anticancer drugs with sustained release.

Operation CASTLE. Radiological Safety

DTIC Science & Technology

1981-04-01

Electronic Section . . . .. 42 5.3 Photodosimetry and Records Section . . . . . . . 43 5.3.1 Film Packet . . . . . . . . . . 43 5.3.2 Dosimeters ...Accuracy of Du Pont Film Packet 559 as a Personnel Dosimeter . . . 61 A.2 Relative Sensitivity of Films Behind Lead Filters . 61 A.3 Variations of...project and Holmes and Narver (H&N) supervisory personnel as radiological- safety monitors. Three schools were conducted: osle at the Nevada Proving

Thermoreflectance microscopy measurements of the Joule heating characteristics of high- Tc superconducting terahertz emitters

NASA Astrophysics Data System (ADS)

Kashiwagi, Takanari; Tanaka, Taiga; Watanabe, Chiharu; Kubo, Hiroyuki; Komori, Yuki; Yuasa, Takumi; Tanabe, Yuki; Ota, Ryusei; Kuwano, Genki; Nakamura, Kento; Tsujimoto, Manabu; Minami, Hidetoshi; Yamamoto, Takashi; Klemm, Richard A.; Kadowaki, Kazuo

2017-12-01

Joule heating is the central issue in order to develop high-power and high-performance terahertz (THz) emission from mesa devices employing the intrinsic Josephson junctions in a layered high transition-temperature Tc superconductor. Here, we describe a convenient local thermal measurement technique using charge-coupled-device-based thermoreflectance microscopy, with the highest spatial resolution to date. This technique clearly proves that the relative temperature changes of the mesa devices between different bias points on the current-voltage characteristics can be measured very sensitively. In addition, the heating characteristics on the surface of the mesa devices can be detected more directly without any special treatment of the mesa surface such as previous coatings with SiC micro-powders. The results shown here clearly indicate that the contact resistance strongly affects the formation of an inhomogeneous temperature distribution on the mesa structures. Since the temperature and sample dependencies of the Joule heating characteristics can be measured quickly, this simple thermal evaluation technique is a useful tool to check the quality of the electrical contacts, electrical wiring, and sample defects. Thus, this technique could help to reduce the heating problems and to improve the performance of superconducting THz emitter devices.

Rapid detection and differentiation of Clonorchis sinensis and Opisthorchis viverrini using real-time PCR and high resolution melting analysis.

PubMed

Cai, Xian-Quan; Yu, Hai-Qiong; Li, Rong; Yue, Qiao-Yun; Liu, Guo-Hua; Bai, Jian-Shan; Deng, Yan; Qiu, De-Yi; Zhu, Xing-Quan

2014-01-01

Clonorchis sinensis and Opisthorchis viverrini are both important fish-borne pathogens, causing serious public health problem in Asia. The present study developed an assay integrating real-time PCR and high resolution melting (HRM) analysis for the specific detection and rapid identification of C. sinensis and O. viverrini. Primers targeting COX1 gene were highly specific for these liver flukes, as evidenced by the negative amplification of closely related trematodes. Assays using genomic DNA extracted from the two flukes yielded specific amplification and their identity was confirmed by sequencing, having the accuracy of 100% in reference to conventional methods. The assay was proved to be highly sensitive with a detection limit below 1 pg of purified genomic DNA, 5 EPG, or 1 metacercaria of C. sinensis. Moreover, C. sinensis and O. viverrini were able to be differentiated by their HRM profiles. The method can reduce labor of microscopic examination and the contamination of agarose electrophoresis. Moreover, it can differentiate these two flukes which are difficult to be distinguished using other methods. The established method provides an alternative tool for rapid, simple, and duplex detection of C. sinensis and O. viverrini.

Rapid Detection and Simultaneous Genotyping of Cronobacter spp. (formerly Enterobacter sakazakii) in Powdered Infant Formula Using Real-time PCR and High Resolution Melting (HRM) Analysis

PubMed Central

Cai, Xian-Quan; Yu, Hai-Qiong; Ruan, Zhou-Xi; Yang, Lei-Liang; Bai, Jian-Shan; Qiu, De-Yi; Jian, Zhi-Hua; Xiao, Yi-Qian; Yang, Jie-Yang; Le, Thanh Hoa; Zhu, Xing-Quan

2013-01-01

Cronobacter spp. is an emerging pathogen that causes meningitis, sepsis, bacteremia, and necrotizing enterocolitis in neonates and children. The present study developed an assay integrating real-time PCR and high resolution melting (HRM) analysis targeting the OmpA gene for the specific detection and rapid identification of Cronobacter spp. (formerly Enterobacter sakazakii) in powdered infant formula. Eleven Cronobacter field isolates and 25 reference strains were examined using one pair of primers, having the accuracy of 100% in reference to conventional methods. The assay was proved to be highly sensitive with a detection limit of 102 CFU/ml without pre-enrichment, and highly concordant (100%) when compared with ISO-IDF 22964 in 89 actual samples. The method performed for Cronobacter spp. detection was less than 24 h, drastically shortened, compared to several days using standard culturing method, it is probe-free and reduces a risk of PCR carryover. Moreover, all Cronobacter strains examined in this study were genotyped into two species according to their HRM profiles. The established method should provide a molecular tool for direct detection and simultaneous genotyping of Cronobacter spp. in powdered infant formula. PMID:23825624

Rapid detection and simultaneous genotyping of Cronobacter spp. (formerly Enterobacter sakazakii) in powdered infant formula using real-time PCR and high resolution melting (HRM) analysis.

PubMed

Cai, Xian-Quan; Yu, Hai-Qiong; Ruan, Zhou-Xi; Yang, Lei-Liang; Bai, Jian-Shan; Qiu, De-Yi; Jian, Zhi-Hua; Xiao, Yi-Qian; Yang, Jie-Yang; Le, Thanh Hoa; Zhu, Xing-Quan

2013-01-01

Cronobacter spp. is an emerging pathogen that causes meningitis, sepsis, bacteremia, and necrotizing enterocolitis in neonates and children. The present study developed an assay integrating real-time PCR and high resolution melting (HRM) analysis targeting the OmpA gene for the specific detection and rapid identification of Cronobacter spp. (formerly Enterobacter sakazakii) in powdered infant formula. Eleven Cronobacter field isolates and 25 reference strains were examined using one pair of primers, having the accuracy of 100% in reference to conventional methods. The assay was proved to be highly sensitive with a detection limit of 10(2) CFU/ml without pre-enrichment, and highly concordant (100%) when compared with ISO-IDF 22964 in 89 actual samples. The method performed for Cronobacter spp. detection was less than 24 h, drastically shortened, compared to several days using standard culturing method, it is probe-free and reduces a risk of PCR carryover. Moreover, all Cronobacter strains examined in this study were genotyped into two species according to their HRM profiles. The established method should provide a molecular tool for direct detection and simultaneous genotyping of Cronobacter spp. in powdered infant formula.

Long-term fate of depleted uranium at Aberdeen and Yuma Proving Grounds: Human health and ecological risk assessments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ebinger, M.H.; Beckman, R.J.; Myers, O.B.

1996-09-01

The purpose of this study was to evaluate the immediate and long-term consequences of depleted uranium (DU) in the environment at Aberdeen Proving Ground (APG) and Yuma Proving Ground (YPG) for the Test and Evaluation Command (TECOM) of the US Army. Specifically, we examined the potential for adverse radiological and toxicological effects to humans and ecosystems caused by exposure to DU at both installations. We developed contaminant transport models of aquatic and terrestrial ecosystems at APG and terrestrial ecosystems at YPG to assess potential adverse effects from DU exposure. Sensitivity and uncertainty analyses of the initial models showed the portionsmore » of the models that most influenced predicted DU concentrations, and the results of the sensitivity analyses were fundamental tools in designing field sampling campaigns at both installations. Results of uranium (U) isotope analyses of field samples provided data to evaluate the source of U in the environment and the toxicological and radiological doses to different ecosystem components and to humans. Probabilistic doses were estimated from the field data, and DU was identified in several components of the food chain at APG and YPG. Dose estimates from APG data indicated that U or DU uptake was insufficient to cause adverse toxicological or radiological effects. Dose estimates from YPG data indicated that U or DU uptake is insufficient to cause radiological effects in ecosystem components or in humans, but toxicological effects in small mammals (e.g., kangaroo rats and pocket mice) may occur from U or DU ingestion. The results of this study were used to modify environmental radiation monitoring plans at APG and YPG to ensure collection of adequate data for ongoing ecological and human health risk assessments.« less

Differential sensitivities to dioxin-like compounds PCB 126 and PeCDF between Tg(cyp1a:gfp) transgenic medaka and zebrafish larvae.

PubMed

Xu, Hongyan; Li, Caixia; Suklai, Pacharaporn; Zeng, Qinghua; Chong, Raymond; Gong, Zhiyuan

2018-02-01

It has been intensively documented that there are species-differences in the sensitivity to dioxin-like compounds (DLCs) in mammalian and avian. However, this issue is still unclear in fish. This study aimed at evaluating the differential sensitivities to DLCs in fish larvae. Here, larvae of Tg(cyp1a:gfp) medaka and Tg(cyp1a:gfp) zebrafish were tested with 2,3,7,8-Tetrachlorodibenzodioxin (TCDD), polychlorinated biphenyl 126 (PCB 126) and 2,3,4,7,8,-Pentachlorodibenzofuran (PeCDF). Comparative analyses were performed on induction of GFP fluorescence, expression of endogenous cyp1a mRNAs and EROD activity between the two species after exposure to these chemicals. We found that PCB 126 and PeCDF exposure at high concentrations induced strong GFP expression in multiple organs (liver, head kidney and gut) in both medaka and zebrafish larvae. Moreover, the expression of endogenous cyp1a mRNA was significantly elevated in the zebrafish larvae exposed to TCDD, PCB 126 and PeCDF at different concentrations. Likewise, almost all the exposure conditions could cause prominent elevation of EROD activity in the zebrafish larvae, while the EROD activities were just slightly elevated in the medaka larvae exposed to 1 nM and 0.5 nM of TCDD as well as to 1.5 nM and 15 nM of PeCDF, but not in the medaka larvae exposed to PCB 126. Taken together, zebrafish was proved to be more sensitive than medaka to PCB 126 and to PeCDF in this study. The findings suggested species-specific sensitivity to DLCs in fish and will facilitate choosing a sensitive and reliable fish model or tool to evaluate the risk of dioxins and DLCs exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analysis of Gibbs monolayer adsorbed at the toluene/water interface by UV-visible partial internal reflection spectrometry.

PubMed

Moriya, Yoshio; Hasegawa, Takeshi; Okada, Tetsuo; Ogawa, Nobuaki; Kawai, Erika; Abe, Kosuke; Ogasawara, Masataka; Kato, Sumio; Nakata, Shinichi

2006-11-15

Gibbs monolayers of lipophilic tetraphenylporphyrinatomanganese(III) and hydrophilic diacid of meso-tetrakis(4-sulfonatopheny)porphyrin adsorbed at the liquid-liquid interface have been analyzed by UV-visible external reflection (ER) and partial internal reflection (PIR) spectra measured at different angles of incidence. The angle-dependent ER and PIR spectra over the Brewster angles (thetaERB and thetaIRB) have readily been measured at the toluene/water interface. As preliminarily expected in our previous study, the present study has first proved that the reflection-absorbance of UV-visible PIR spectra quantitatively agrees with the theoretical calculations for the Gibbs monolayer over thetaIRB. In addition, it has also been proved that the absorbance of the PIR spectra is greatly enhanced in comparison to that of the ATR spectra. The enhancement is caused by an optical effect in the monolayer sandwiched between two phases of toluene and water that have different but refractive indices close to each other. This optical enhancement requires an optically perfect contact between the phases, which is difficult to prepare for a solid-solid contact. At the liquid/liquid interface, however, an ideal optical contact is easily realized, which makes the enhancement as much as the theoretical expectation. The PIR spectrometry will be recognized to be a new high-sensitive analytical tool to study Gibbs monolayer at the liquid/liquid interface.

Narcolepsy and disorders of excessive somnolence.

PubMed

Dyken, Mark E; Yamada, Thoru

2005-06-01

Recent studies provide valid criteria that help differentiate idiopathic narcolepsy from other disorders of excessive daytime somnolence [3]. Research to date suggests that idiopathic narcolepsy might properly be considered a disorder of excessive sleepiness with dysfunctional REM-sleep mechanisms, clinically evidenced as cataplexy and electrophysiologically recognized as SOREMPs. Given these criteria, a diagnosis can generally be made using a combination of history, PSG, and MSLT. Traditionally, the medical treatment of idiopathic narcolepsy has centered on a two-drug regimen (stimulants for sleepiness and TCAs for cataplexy and auxiliary symptoms). Some newer medications are proving efficacious for sleepiness with minimal adverse effects, whereas others may provide a single-drug regimen that simultaneously addresses sleepiness and cataplexy [18]. New research has allowed some experts to hypothesize that idiopathic narcolepsy may be the result of a genetic predisposition to autoimmune disease [176]. It is possible that aberrant genetic coding of elements in the hypocretin/orexin systems allows a sensitivity to inducible and possibly virally mediated changes, which leave cells in the lateral hypothalamus susceptible to autoimmune attack [96]. As such, genetic screening of high-risk individuals might eventually rationalize the prophylactic use of immunosuppressants in some instances. In the future, for atypical cases(poorly responsive to therapy), genetic, CSF, and brain imaging studies, and possibly even neuronal transplantation may prove beneficial in the assessment and treatment of idiopathic narcolepsy.

A nanocluster-based fluorescent sensor for sensitive hemoglobin detection.

PubMed

Yang, Dongqin; Meng, Huijie; Tu, Yifeng; Yan, Jilin

2017-08-01

In this report, a fluorescence sensor for sensitive detection of hemoglobin was developed. Gold nanoclusters were first synthesized with bovine serum albumin. It was found that both hydrogen peroxide and hemoglobin could weakly quench the fluorescence from the gold nanoclusters, but when these two were applied onto the nanolcusters simultaneously, a much improved quenching was resulted. This enhancing effect was proved to come from the catalytic generation of hydroxyl radical by hemoglobin. Under an optimized condition, the quenching linearly related to the concentration of hemoglobin in the range of 1-250nM, and a limit of detection as low as 0.36nM could be obtained. This provided a sensitive means for the quantification of Hb. The sensor was then successfully applied for blood analyses with simple sample pretreatment. Copyright © 2017 Elsevier B.V. All rights reserved.

SEM analysis of ionizing radiation effects in an analog to digital converter /AD571/

NASA Technical Reports Server (NTRS)

Gauthier, M. K.; Perret, J.; Evans, K. C.

1981-01-01

The considered investigation is concerned with the study of the total-dose degradation mechanisms in an IIL analog to digital (A/D) converter. The A/D converter is a 10 digit device having nine separate functional units on the chip which encompass several hundred transistors and circuit elements. It was the objective of the described research to find the radiation sensitive elements by a systematic search of the devices on the LSI chip. The employed technique using a scanning electron microscope to determine the functional blocks of an integrated circuit which are sensitive to ionizing radiation and then progressively zeroing in on the soft components within those blocks, proved extremely successful on the AD571. Four functional blocks were found to be sensitive to radiation, including the Voltage Reference, DAC, IIL Clock, and IIL SAR.

Analysis of mixed traffic flow with human-driving and autonomous cars based on car-following model

NASA Astrophysics Data System (ADS)

Zhu, Wen-Xing; Zhang, H. M.

2018-04-01

We investigated the mixed traffic flow with human-driving and autonomous cars. A new mathematical model with adjustable sensitivity and smooth factor was proposed to describe the autonomous car's moving behavior in which smooth factor is used to balance the front and back headway in a flow. A lemma and a theorem were proved to support the stability criteria in traffic flow. A series of simulations were carried out to analyze the mixed traffic flow. The fundamental diagrams were obtained from the numerical simulation results. The varying sensitivity and smooth factor of autonomous cars affect traffic flux, which exhibits opposite varying tendency with increasing parameters before and after the critical density. Moreover, the sensitivity of sensors and smooth factors play an important role in stabilizing the mixed traffic flow and suppressing the traffic jam.

Utility of Acridine Orange staining for detection of bacteria from positive blood cultures.

PubMed

Neeraja, M; Lakshmi, V; Padmasri, C; Padmaja, K

2017-08-01

The diagnostic performance of AO stain was evaluated for the detection of bacteria and or fungi from positive blood cultures. The sensitivity of Gram stain (GS) was 98.26% while Acridine Orange (AO) stain proved to be more sensitive (100%) with a Positive and Negative Predictive Value of 100% each. The specificity of both the stains was 100%. Overall agreement between the two stains was 98.23% (688/700). The organisms that were missed by GS and positive by AO were Candida species (Sutton, 2006) and Gram negative bacilli (GNB) (Sutton, 2006). Sensitivity of GS was 82.35% and AO was 100% among mixed cultures. Immediate reporting of the results of AO stain would have a significant impact on clinical management of patients with serious blood stream infections. Copyright © 2017 Elsevier B.V. All rights reserved.

Demonstration of a superconducting nanowire single photon detector with an ultrahigh polarization extinction ratio over 400.

PubMed

Xu, Ruiying; Li, Yongchao; Zheng, Fan; Zhu, Guanghao; Kang, Lin; Zhang, Labao; Jia, Xiaoqing; Tu, Xuecou; Zhao, Qingyuan; Jin, Biaobing; Xu, Weiwei; Chen, Jian; Wu, Peiheng

2018-02-19

Polarization sensitive photo-detectors are the key to the implementation of the polarimetric imaging systems, which are proved to have superior performance than their traditional counterparts based on intensity discriminations. In this article, we report the demonstration of a superconducting nanowire single photon detector (SNSPD) of which the response is ultra-sensitive to the polarization state of the incident photons. Measurements carried out on a fabricated SNSPD show that a device efficiency of ~48% can be achieved at 1550 nm for the case of parallel polarization, which is ~420 times larger than that for the case of perpendicular polarization. While the reported polarization ultra-sensitive technique is demonstrated on a single-pixel SNSPD, it is also fully compatible with the multi-pixel SNSPD array platforms that emerged recently.

Review of the use of Ceramium tenuicorne growth inhibition test for testing toxicity of substances, effluents, products sediment and soil

NASA Astrophysics Data System (ADS)

Eklund, Britta

2017-08-01

A growth inhibition test has been developed based on two clones of the red macroalga Ceramium tenuicorne, one originating from 7 PSU and the other from 20 PSU. The species can be adapted to different salinities and the test can be carried out between 4 and 32 PSU. This test became an ISO standard in 2010 (ISO 107 10) for testing of chemicals and water effluents. In this study new and published data has been compiled on toxicity of single substances, waste waters from pulp mills, leachates from antifouling paints, harbour sediments and soil used for maintenance of leisure boats. The results show that the alga is sensitive to both metals and organic compounds and to biocides used in antifouling paints. By testing leachates from antifouling paints these could be ranked according to their toxicity. Similarly, the toxicity of waste waters from pulp mills was determined and the efficiency of secondary treatment evaluated. Further, the test method proved useful to test the toxicity in sediment samples. Sediments from small town harbours and ship lanes were shown to be harmful and compounds originating from antifouling paints were responsible for a large part of the inhibiting effect. The alga proved to be sensitive to contaminants leaking from boat yard soil. The growth inhibition test is a robust test that has high repeatability and reproducibility and easily can be applied on water, soil and sediment samples without being too costly. The species is found worl-wide in temperate waters, which makes the results relevant for large areas. In the Baltic Sea C. tenuicorne is the most common red alga species and is thus particularly relevant for this area. The overall results show that contaminants from boat activities and the use of antifouling paints in particular pose a threat to the environment.

Evaluation of depleted uranium in the environment at Aberdeen Proving Grounds, Maryland and Yuma Proving Grounds, Arizona. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kennedy, P.L.; Clements, W.H.; Myers, O.B.

1995-01-01

This report represents an evaluation of depleted uranium (DU) introduced into the environment at the Aberdeen Proving Grounds (APG), Maryland and Yuma Proving Grounds (YPG) Arizona. This was a cooperative project between the Environmental Sciences and Statistical Analyses Groups at LANL and with the Department of Fishery and Wildlife Biology at Colorado State University. The project represents a unique approach to assessing the environmental impact of DU in two dissimilar ecosystems. Ecological exposure models were created for each ecosystem and sensitivity/uncertainty analyses were conducted to identify exposure pathways which were most influential in the fate and transport of DU inmore » the environment. Research included field sampling, field exposure experiment, and laboratory experiments. The first section addresses DU at the APG site. Chapter topics include bioenergetics-based food web model; field exposure experiments; bioconcentration by phytoplankton and the toxicity of U to zooplankton; physical processes governing the desorption of uranium from sediment to water; transfer of uranium from sediment to benthic invertebrates; spead of adsorpion by benthic invertebrates; uptake of uranium by fish. The final section of the report addresses DU at the YPG site. Chapters include the following information: Du transport processes and pathway model; field studies of performance of exposure model; uptake and elimination rates for kangaroo rates; chemical toxicity in kangaroo rat kidneys.« less

Synthesis and physicochemical characterization of chitin dihexanoate--A new biocompatible chitin derivative--In comparison to chitin dibutyrate.

PubMed

Skołucka-Szary, Karolina; Ramięga, Aleksandra; Piaskowska, Wanda; Janicki, Bartosz; Grala, Magdalena; Rieske, Piotr; Bartczak, Zbigniew; Piaskowski, Sylwester

2016-03-01

Chitin dihexanoate (DHCH) is the novel biocompatible and technologically friendly highly substituted chitin diester. Here we described optimization of DHCH and chitin dibutyrate (dibutyryl chitin, DBC) synthesis conditions (temperature and reaction time) to obtain desired polymers with high reaction yield, high substitution degree (close to 2) and appropriately high molecular weights. A two-step procedure, employing acidic anhydrides (hexanoic or butyric anhydride) as the acylation agent and methanesulfonic acid both as the catalyst and the reaction medium, was applied. Chemical structures of DBC and DHCH were confirmed by NMR ((1)H and (13)C) and IR investigations. Mechanical properties, thermogravimetric analysis, differential scanning calorimetry and biocompatibility (Neutral red uptake assay, Skin Sensitization and Irritation Tests) were assessed. Both polymers proved highly biocompatible (non-cytotoxic in vitro, non-irritating and non-allergic to skin) and soluble in several organic solvents (dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, acetone, ethanol and others). It is worth emphasizing that DHCH and DBC can be easily processed by solvent casting method and the salt-leaching method, what gives the opportunity to prepare highly porous structures, which can be further successfully applied as the material for wound dressings and scaffolds for tissue engineering. Copyright © 2015 Elsevier B.V. All rights reserved.

Effectiveness of real-time polymerase chain reaction assay for the detection of Mycobacterium tuberculosis in pathological samples: a systematic review and meta-analysis.

PubMed

Babafemi, Emmanuel O; Cherian, Benny P; Banting, Lee; Mills, Graham A; Ngianga, Kandala

2017-10-25

Rapid and accurate diagnosis of tuberculosis (TB) is key to manage the disease and to control and prevent its transmission. Many established diagnostic methods suffer from low sensitivity or delay of timely results and are inadequate for rapid detection of Mycobacterium tuberculosis (MTB) in pulmonary and extra-pulmonary clinical samples. This study examined whether a real-time polymerase chain reaction (RT-PCR) assay, with a turn-a-round time of 2 h, would prove effective for routine detection of MTB by clinical microbiology laboratories. A systematic literature search was performed for publications in any language on the detection of MTB in pathological samples by RT-PCR assay. The following sources were used MEDLINE via PubMed, EMBASE, BIOSIS Citation Index, Web of Science, SCOPUS, ISI Web of Knowledge and Cochrane Infectious Diseases Group Specialised Register, grey literature, World Health Organization and Centres for Disease Control and Prevention websites. Forty-six studies met set inclusion criteria. Generated pooled summary estimates (95% CIs) were calculated for overall accuracy and bivariate meta-regression model was used for meta-analysis. Summary estimates for pulmonary TB (31 studies) were as follows: sensitivity 0.82 (95% CI 0.81-0.83), specificity 0.99 (95% CI 0.99-0.99), positive likelihood ratio 43.00 (28.23-64.81), negative likelihood ratio 0.16 (0.12-0.20), diagnostic odds ratio 324.26 (95% CI 189.08-556.09) and area under curve 0.99. Summary estimates for extra-pulmonary TB (25 studies) were as follows: sensitivity 0.70 (95% CI 0.67-0.72), specificity 0.99 (95% CI 0.99-0.99), positive likelihood ratio 29.82 (17.86-49.78), negative likelihood ratio 0.33 (0.26-0.42), diagnostic odds ratio 125.20 (95% CI 65.75-238.36) and area under curve 0.96. RT-PCR assay demonstrated a high degree of sensitivity for pulmonary TB and good sensitivity for extra-pulmonary TB. It indicated a high degree of specificity for ruling in TB infection from sampling regimes. This was acceptable, but may better as a rule out add-on diagnostic test. RT-PCR assays demonstrate both a high degree of sensitivity in pulmonary samples and rapidity of detection of TB which is an important factor in achieving effective global control and for patient management in terms of initiating early and appropriate anti-tubercular therapy. PROSPERO CRD42015027534 .

Diagnostic accuracy of fundal height and handheld ultrasound-measured abdominal circumference to screen for fetal growth abnormalities

PubMed Central

Haragan, Adriane F.; Hulsey, Thomas C.; Hawk, Angela F.; Newman, Roger B.; Chang, Eugene Y.

2015-01-01

OBJECTIVE We sought to compare fundal height and handheld ultrasound–measured fetal abdominal circumference (HHAC) for the prediction of fetal growth restriction (FGR) or large for gestational age. STUDY DESIGN This was a diagnostic accuracy study in nonanomalous singleton pregnancies between 24 and 40 weeks’ gestation. Patients underwent HHAC and fundal height measurement prior to formal growth ultrasound. FGR was defined as estimated fetal weight less than 10%, whereas large for gestational age was defined as estimated fetal weight greater than 90%. Sensitivity and specificity were calculated and compared using methods described elsewhere. RESULTS There were 251 patients included in this study. HHAC had superior sensitivity and specificity for the detection of FGR (sensitivity, 100% vs 42.86%) and (specificity, 92.62% vs 85.24%). HHAC had higher specificity but lower sensitivity when screening for LGA (specificity, 85.66% vs 66.39%) and (sensitivity, 57.14% vs 71.43%). CONCLUSION HHAC could prove to be a valuable screening tool in the detection of FGR. Further studies are needed in a larger population. PMID:25818672

Enhanced Photoelectrochemical Water Splitting Behaviour of Tuned Band Gap CdSe QDs Sensitized LaB₆.

PubMed

Babu, M Soban; Sivanantham, A; Chakravarthi, B Barath; Kannan, R Sujith; Panda, Subhendu K; Berchmans, L John; Arya, S B; Sreedhar, Gosipathala

2017-01-01

We report the fabrication of tuned band gap quantum dots sensitized LaB₆ hybrid nanostructures and their application as a photoanode for photoelectrochemical water splitting. The lanthanum hexaboride (LaB₆) obtained by molten salt electrolysis method is sensitized with different sized CdSe quantum dots, which form a multiple-level hierarchical heterostructure and such design enhance the light absorption and charge carrier separation, which in turn showed higher photocurrent density compared to that of pristine LaB₆. When LaB₆ is sensitized with CdSe quantum dots of different band gaps, which have the absorption in the green and red (530 and 605 nm) regions in visible light, developed a ten times higher photocurrent density (11.0 mA cm(−2)) compared to that of pristine LaB6 (0.5 mA cm(−2) at 0.75 V vs. Ag/AgCl) in 1 M Na₂S electrolyte under illumination. These results prove that the tuned band gap quantum dots sensitized LaB₆ heterostructures are an ideal candidate for a photoanode in solar water splitting applications.

A wavelength-modulated localized surface plasmon resonance (LSPR) optical fiber sensor for sensitive detection of mercury(II) ion by gold nanoparticles-DNA conjugates.

PubMed

Jia, Shuo; Bian, Chao; Sun, Jizhou; Tong, Jianhua; Xia, Shanhong

2018-05-08

The study presented herein investigated an easy preparation, high performance, wavelength-modulated LSPR optical fiber chemosensor coated by gold nanospheres(AuNS) for Hg 2+ detection based on thymine-Hg 2+ -thymine base pair mismatches and the coupled plasmonic resonance effect.Utilizing electrostatic self-assembly method, the high density and dispersivity monolayer AuNS coated LSPR fiber sensor had the near field refractive index sensitivity up to 2016 nm/RIU. The single-strand probe DNA served as a binding element for free AuNS labelled-target DNA conjugates was attached to the monolayer AuNS by Au-S bond. In the present of Hg 2+ , the coupled plasmonic resonance band between monolayer AuNS and free AuNS was produced by thymine-Hg 2+ -thymine structure and leaded to red-shift of LSPR peak. Under the optimal conditions, the enlarged red-shift in peak of LSPR spectroscopy was linearly with the concentration of Hg 2+ in the range from 1.0 × 10 -9 to 5.0 × 10 -8 M with the coefficient of 0.976. The limit of detection was 0.7 nM(S/N = 3). The specificity of the sensor was proved high by evaluating the response to other heavy metal ions. The proposed fiber sensor provided a label-free, miniature, low-cost approach for the Hg 2+ detection and had potential in real environmental evaluations. Copyright © 2018 Elsevier B.V. All rights reserved.

Trace hydrogen sulfide gas sensor based on tungsten sulfide membrane-coated thin-core fiber modal interferometer

NASA Astrophysics Data System (ADS)

Deng, Dashen; Feng, Wenlin; Wei, Jianwei; Qin, Xiang; Chen, Rong

2017-11-01

A novel fiber-optic hydrogen sulfide sensor based on a thin-core Mach-Zehnder fiber modal interferometer (TMZFI) is demonstrated and fabricated. This in-line interferometer is composed of a short section of thin-core fiber sandwiched between two standard single mode fibers, and the fast response to hydrogen sulfide is achieved via the construction of tungsten sulfide film on the outside surface of the TMZFI using the dip-coating and calcination technique. The fabricated sensing nanofilm is characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS) spectrometer, Fourier transform infrared (FTIR) and spectroscopic analysis technology, etc. Experimental results showed that the WS2 sensing film has a hexagonal structure with a compact and porous morphology. The XPS and FTIR indicate that the existence of two elements (W and S) is demonstrated. With the increasing concentration of hydrogen sulfide, the interference spectra appear blue shift. In addition, a high sensitivity of 18.37 pm/ppm and a good linear relationship are obtained within a measurement range from 0 to 80 ppm. In addition, there is an excellent selectivity for H2S, which has also been proved by the surface adsorption energy results of tungsten sulfide with four gases (H2S, N2, O2 and CO2) by using the density functional theory calculations. This interferometer has the advantages of simple structure, high sensitivity and easy manufacture, and could be used in the safety monitoring field of hydrogen sulfide gas.

A parametric approach for simultaneous bias correction and high-resolution downscaling of climate model rainfall

NASA Astrophysics Data System (ADS)

Mamalakis, Antonios; Langousis, Andreas; Deidda, Roberto; Marrocu, Marino

2017-03-01

Distribution mapping has been identified as the most efficient approach to bias-correct climate model rainfall, while reproducing its statistics at spatial and temporal resolutions suitable to run hydrologic models. Yet its implementation based on empirical distributions derived from control samples (referred to as nonparametric distribution mapping) makes the method's performance sensitive to sample length variations, the presence of outliers, the spatial resolution of climate model results, and may lead to biases, especially in extreme rainfall estimation. To address these shortcomings, we propose a methodology for simultaneous bias correction and high-resolution downscaling of climate model rainfall products that uses: (a) a two-component theoretical distribution model (i.e., a generalized Pareto (GP) model for rainfall intensities above a specified threshold u*, and an exponential model for lower rainrates), and (b) proper interpolation of the corresponding distribution parameters on a user-defined high-resolution grid, using kriging for uncertain data. We assess the performance of the suggested parametric approach relative to the nonparametric one, using daily raingauge measurements from a dense network in the island of Sardinia (Italy), and rainfall data from four GCM/RCM model chains of the ENSEMBLES project. The obtained results shed light on the competitive advantages of the parametric approach, which is proved more accurate and considerably less sensitive to the characteristics of the calibration period, independent of the GCM/RCM combination used. This is especially the case for extreme rainfall estimation, where the GP assumption allows for more accurate and robust estimates, also beyond the range of the available data.

Investigation of an Outbreak of Photodermatitis Confined to One Shop in a Large Factory

PubMed Central

Jones, D. W. Wynn

1962-01-01

Out of 106 men employed in a foundry attached to a large factory, 29 men developed a photosensitization dermatitis over the period of three months. Three men out of 1,700 employed in the remainder of the works developed a similar eruption, but no common factor was apparent. Owing to the very high incidence in the foundry, a sensitizer associated with the process was suspected and it seemed likely that it would prove to be an atmospheric contaminant. Many chemical investigations and skin tests were carried out without positive result, though much interesting information regarding combustion products of various materials was obtained. Some of the men were referred to dermatological clinics in three neighbouring hospitals. In one of these clinics, a similarity was noticed between six cases recently seen there. This suggested that the sensitizer was not confined to the foundry or to the factory. The cause was eventually traced to an additive (tetrachlorsalicylanilide) in a popular brand of toilet soap, and it was evident that the photosensitivity in varying degrees of severity was widespread over the Home Counties, if not much of the country. It had not hitherto been recognized, as mild cases had required little or no treatment, and severe cases were widely disseminated. It is probable that, had it not been for the very high incidence in the foundry, the eruption would have remained unrecognized for much longer. The high incidence in the foundry is attributed to the frequency with which the men washed there, and possibly to some local aggravating factor not yet discovered. Images PMID:14452243

Sensitivity of hepatobiliary imaging and real-time ultrasonography in the detection of acute cholecystitis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fink-Bennett, D.; Freitas, J.E.; Ripley, S.D.

To determine the sensitivity of hepatobiliary imaging (HBI) and strict- and liberal-criteria real-time ultrasonography (RTUS), the authors retrospectively analyzed 100 cases of pathologically proved acute cholecystitis (AC). A positive HBI was one in which there was nonvisualization of the gallbladder up to four hours after the administration of technetium 99m-disofenin. In the absence of hypoalbuminemia, cirrhosis, or ascites, pathognomonic RTUS findings (strict criteria) for AC were wall edema and/or pericholecystic fluid. Findings indicative of AC (liberal criteria) included the demonstration of stones, a thick gallbladder wall, nonshadowing echoes, or the ultrasonographic Murphy's sign. Of the 100 cases of AC, 91more » were calculous, and nine were acalculous. Four of 100 patients had associated choledocholithiasis. The sensitivities in detecting calculous AC were as follows: HBI, 97%; liberal-criteria RTUS, 86%; and strict-criteria RTUS, 24%. The sensitivities in detecting acalculous AC were as follows: HBI, 100%; liberal-criteria RTUS, 89%; and strict-criteria RTUS, 44%.« less

Allergic sensitization: screening methods

PubMed Central

2014-01-01

Experimental in silico, in vitro, and rodent models for screening and predicting protein sensitizing potential are discussed, including whether there is evidence of new sensitizations and allergies since the introduction of genetically modified crops in 1996, the importance of linear versus conformational epitopes, and protein families that become allergens. Some common challenges for predicting protein sensitization are addressed: (a) exposure routes; (b) frequency and dose of exposure; (c) dose-response relationships; (d) role of digestion, food processing, and the food matrix; (e) role of infection; (f) role of the gut microbiota; (g) influence of the structure and physicochemical properties of the protein; and (h) the genetic background and physiology of consumers. The consensus view is that sensitization screening models are not yet validated to definitively predict the de novo sensitizing potential of a novel protein. However, they would be extremely useful in the discovery and research phases of understanding the mechanisms of food allergy development, and may prove fruitful to provide information regarding potential allergenicity risk assessment of future products on a case by case basis. These data and findings were presented at a 2012 international symposium in Prague organized by the Protein Allergenicity Technical Committee of the International Life Sciences Institute’s Health and Environmental Sciences Institute. PMID:24739743

Devaney chaos, Li-Yorke chaos, and multi-dimensional Li-Yorke chaos for topological dynamics

NASA Astrophysics Data System (ADS)

Dai, Xiongping; Tang, Xinjia

2017-11-01

Let π : T × X → X, written T↷π X, be a topological semiflow/flow on a uniform space X with T a multiplicative topological semigroup/group not necessarily discrete. We then prove: If T↷π X is non-minimal topologically transitive with dense almost periodic points, then it is sensitive to initial conditions. As a result of this, Devaney chaos ⇒ Sensitivity to initial conditions, for this very general setting. Let R+↷π X be a C0-semiflow on a Polish space; then we show: If R+↷π X is topologically transitive with at least one periodic point p and there is a dense orbit with no nonempty interior, then it is multi-dimensional Li-Yorke chaotic; that is, there is a uncountable set Θ ⊆ X such that for any k ≥ 2 and any distinct points x1 , … ,xk ∈ Θ, one can find two time sequences sn → ∞ ,tn → ∞ with Moreover, let X be a non-singleton Polish space; then we prove: Any weakly-mixing C0-semiflow R+↷π X is densely multi-dimensional Li-Yorke chaotic. Any minimal weakly-mixing topological flow T↷π X with T abelian is densely multi-dimensional Li-Yorke chaotic. Any weakly-mixing topological flow T↷π X is densely Li-Yorke chaotic. We in addition construct a completely Li-Yorke chaotic minimal SL (2 , R)-acting flow on the compact metric space R ∪ { ∞ }. Our various chaotic dynamics are sensitive to the choices of the topology of the phase semigroup/group T.

The Role of Rapid Glacier Retreat and Paraglacial Landscape Transformation in Controlling the Evolution of High Arctic Coastal Systems

NASA Astrophysics Data System (ADS)

Strzelecki, M. C.; Long, A. J.; Zagorski, P.

2017-12-01

The rapid retreat of glaciers observed since the end of the Little Ice Age (LIA) led to a dramatic transformation of High Arctic landscape. This change is apparent in slope, valley and glacier foreland systems, where glacigenic landforms are being denudated by fluvial, aeolian or mass-wasting processes that are being accelerated by permafrost degradation. However, the impact of these changes on the coastal zone is uncertain because of few studies of pre- and post-LIA coastal change. This paper addresses this deficiency by detailing the patterns and processes of post-LIA coastal zone changes in Svalbard - key area for observation of recent paraglacial landscape change in the High Arctic. By application of a mosaic of geomorphological, sedimentological and remote sensing techniques we proved that studied coastal systems (i.e. Billefjorden, Bellsund, Hornsund) abruptly responded to post-LIA deglaciation, permafrost thaw, extreme slope processes and shifts in glaciated catchments. Most of studied coastal systems were characterised by more rapid morphodynamic adjustments than previously thought. Under intervals characterized by a warming climate, retreating local ice masses and shortened sea-ice seasons most of studied coastal systems rapidly responded to an excess of freshly released sediments and experienced significant geomorphological changes (Figure 1). The increased supply of sediments led to the accumulation of new coastal landforms such as extensive gravel-dominated barriers, spits and tidal flats, which are highly sensitive recorders of recent environmental change. We also proved that the development of the post-LIA Svalbard coast is closely linked to the rate of sediment excavation from relict sediment storage systems, such as alluvial fans and outwash plains, that developed across a wide coast plains between the glacier valleys and the fjord during the Holocene. The results are synthesised to propose a new conceptual model of High Arctic paraglacial coastal system, with the aim of contributing towards a unifying concept of cold region landscape evolution and providing direction for future research regarding the state of High Arctic coastal evolution.This paper is a contribution to the NCN projects UMO2013/11/B/ST10/00283 and UMO2013/08/S/ST10/00585.

A Methodology for Modeling Confined, Temperature Sensitive Cushioning Systems

DTIC Science & Technology

1980-06-01

thickness of cushion T, and®- s temperature 0, and as a dependent variable, G, the peak acceleration. The initial model, Equation (IV-11), proved deficient ...k9) = TR * TCTH ALV(60) = Tk * TCTH AL2 V6)= Tk2 * FCTH V2 =TRk * TCrFH *AL V(6~3) =THZ * TC.TH AU! V(,34) =TRa * TCTH 141 Yj)=Tks * T(-Th * AL V(.4b

Parameters Estimation For A Patellofemoral Joint Of A Human Knee Using A Vector Method

NASA Astrophysics Data System (ADS)

Ciszkiewicz, A.; Knapczyk, J.

2015-08-01

Position and displacement analysis of a spherical model of a human knee joint using the vector method was presented. Sensitivity analysis and parameter estimation were performed using the evolutionary algorithm method. Computer simulations for the mechanism with estimated parameters proved the effectiveness of the prepared software. The method itself can be useful when solving problems concerning the displacement and loads analysis in the knee joint.

Reflections of a Wave: An Analysis of Photonic Doppler Velocimetry Systems

DTIC Science & Technology

2015-03-16

system employed by the Advanced Initiation Sciences team, (Munitions Direc - torate, AFRL) is capable of explosive sensitivity testing. The errors from...1961, experiments proved that Semenov Theory aligned well with well- stirred liquids [25, p. 179]. In combat applications, the military usually utilizes...solid explosives instead of liquid ones due to the higher stability of solid-molded explosives where conduction has a huge influence on initiation