216 research outputs found
Further Dimensions for Sensing in Biofluids: Distinguishing Bioorganic Analytes by the Salt-Induced Adaptation of a Cucurbit[7]uril-Based Chemosensor
Insufficient binding selectivity of chemosensors often renders biorelevant metabolites indistinguishable by the widely used indicator displacement assay. Array-based chemosensing methods are a common workaround but require additional effort for synthesizing a chemosensor library and setting up a sensing array. Moreover, it can be very challenging to tune the inherent binding preference of macrocyclic systems such as cucurbit[n]urils (CBn) by synthetic means. Using a novel cucurbit[7]uril-dye conjugate that undergoes salt-induced adaptation, we now succeeded in distinguishing 14 bioorganic analytes from each other through the facile stepwise addition of salts. The salt-specific concentration-resolved emission provides additional information about the system at a low synthetic effort. We present a data-driven approach to translate the human-visible curve differences into intuitive pairwise difference measures. Ion mobility experiments combined with density functional theory calculations gave further insights into the binding mechanism and uncovered an unprecedented ternary complex geometry for CB7. TThis work introduces the non-selectively binding, salt-adaptive cucurbit[n]uril system for sensing applications in biofluids such as urine, saliva, and blood serum
Heavy Meson Production at COSY - 11
The COSY-11 collaboration has measured the total cross section for the pp -->
pp eta-prime and pp --> pp eta reactions in the excess energy range from
Q = 1.5 MeV to Q = 23.6 MeV and from Q = 0.5 MeV to Q = 5.4 MeV,
respectively.
Measurements have been performed with the total luminosity of 73 nb^(-1) for
the pp --> pp eta reaction and 1360 nb^(-1) for the pp --> pp eta-prime one.
Recent results are presented and discussed.Comment: Invited talk at 4th International Conference on Physics at Storage
Rings (STORI 99), Bloomington, Indiana, USA, September 12-16, 199
Near-Threshold eta Meson Production in Proton-Proton Collisions
The production of eta mesons has been measured in the proton-proton
interaction close to the reaction threshold using the COSY-11 internal facility
at the cooler synchrotron COSY. Total cross sections were determined for eight
different excess energies in the range from 0.5 MeV to 5.4 MeV. The energy
dependence of the total cross section is well described by the available
phase-space volume weighted by FSI factors for the proton-proton and proton-eta
pairs.Comment: 9 pages, 1 table, 5 figure
Anchoring of Consumers’ Inflation Expectations: Evidence from Microdata
In this paper we explore the degree of anchoring of consumers' long-run inflation expectations. If expectations are firmly anchored, short- and long-run expectations should show no comovement in response to transitory shocks. Utilizing the University of Michigan Survey of Consumer's rotating panel microstructure, we can identify changes in inflation expectations of individual consumers over time. Our results indicate that long-run inflation expectations became more anchored over the last decades. While the degree of comovement fell significantly after 1996, the probability of a joint adjustment stayed constant. Regarding the possible determinants, we find that consumers' rising interest rate expectations and perceived news on the monetary policy stance have a detrimental effect on the anchoring of long-run expectations. This effect is no longer present in the post-1996 period. Notably, a positive effect of perceived news on government debt on the degree of comovement emerges after 1996, alluding to a potentially problematic link between fiscal and monetary policy
Total Cross Section of the Reaction pp \to pK^+\Lambda Close to Threshold
The energy dependence of the total cross section for the pp \to pK^+\Lambda
reaction was measured in the threshold region covering the excess energy range
up to 7MeV.
Existing model calculations describe the slope of the measured cross sections
well, but are too low by a factor of two to three in rate.
The data were used for a precise determination of the beam momentum of the
COSY-synchrotron.Comment: 11 pages, 5 figure
Resting and Post Bronchial Challenge Testing Carbon Dioxide Partial Pressure in Individuals with and without Asthma
Objective: There is conflicting evidence about resting carbon dioxide levels in asthmatic individuals. We wanted to determine if transcutaneously measured carbon dioxide levels prior and during bronchial provocation testing differ according to asthma status reflecting dysfunctional breathing. Methods: We investigated active firefighters and policemen by means of a validated questionnaire on respiratory symptoms, spirometry, bronchial challenge testing with methacholine (MCT) and measurement of transcutaneous blood carbon dioxide partial pressure (PtcCO 2) at rest prior performing spirometry, one minute and five minutes after termination of MCT. A respiratory physician blinded to the PtcCO2 results assigned a diagnosis of asthma after reviewing the available study data and the files of the workers medical screening program. Results: The study sample consisted of 128 male and 10 female individuals. Fifteen individuals (11%) had physiciandiagnosed asthma. There was no clinically important difference in median PtcCO 2 at rest, one and five minutes after recovery from MCT in asthmatics compared to non-asthmatics (35.6 vs 35.7 mmHg, p = 0.466; 34.7 vs 33.4 mmHg, p = 0.245 and 37.4 vs 36.4 mmHg, p = 0.732). The median drop in PtcCO2 during MCT and the increase after MCT was lower in asthmatics compared to non-asthmatics (0.1 vs 3.2 mmHg, p = 0.014 and 1.9 vs 2.9 mmHg, p = 0.025). Conclusions: PtcCO2 levels at rest prior and during recovery after MCT do not differ in individuals with or without physicia
Comparison of Lambda and Sigma(0) Threshold Production in Proton-Proton Collisions
Threshold measurements of the associated strangeness production reactions pp
--> p K(+) Lambda and pp --> p K(+) Sigma(0) are presented. Although slight
differences in the shapes of the excitation functions are observed, the most
remarkable feature of the data is that at the same excess energy the total
cross section for the Sigma(0) production appears to be about a factor of 28
smaller than the one for the Lambda particle. It is concluded that strong
Sigma(0)-p final state interactions, and in particular the Sigma-N --> Lambda-p
conversion reaction, are the likely cause of the depletion for the yield in the
Sigma signal. This hypothesis is in line with other experimental evidence in
the literature.Comment: 13 pages, 3 figures, 1 tabl
Caregiver perceptions of children who have complex communication needs following a home-based intervention using augmentative and alternative communication in rural Kenya: an intervention note:Home-based intervention using AAC in rural Kenya
A high level of unmet communication need exists amongst children with developmental disabilities in sub-Saharan Africa. This study investigated preliminary evidence of the impact associated with a home-based, caregiver-implemented intervention employing AAC methods, with nine children in rural Kenya who have complex communication needs. The intervention used mainly locally-sourced low-tech materials, and was designed to make use of the child's strengths and the caregiver's natural expertise. A pretest-posttest design was used in the study. Data were gathered using an adapted version of the Communication Profile, which was based on the International Classification of Functioning, Disability, and Health (ICF) framework. The non-parametric Wilcoxon signed-rank test was applied to data from the first two sections of the Communication Profile-Adapted. Qualitative analysis was conducted on the final section. The data provided evidence of statistically significant positive changes in caregiver perceptions of communication at the levels of Body Structure and Function, and Activities for Communication. Also, analysis of the Participation for Communication section revealed some expansion to the children's social activities. The potential impact of the home-based intervention would benefit from investigation on a larger scale. Limitations of the study are discussed
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