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The aim of this communication is to describe the range of applications of GaN-based platforms for trace detection and identification of biological and chemical agents using SERS technique. The methods of nano-structuring of GaN surface for SERS application are briefly described. The results of employing SERS method for analysis of Fentanyl and Bacillus Atrophaeus spores is demonstrated. The arguments are summarized which show the universal feature of GaN-based platforms as SERS sensor.

Dipicolinic acid (DPA) is an essential component for the protection of DNA in bacterial endospores and is often used as a biomarker for spore detection. Depending upon the pH of the solution, DPA exists in different ionic forms. Therefore, it is important to understand how these ionic forms influence spectroscopic response. In this work, we characterize Raman and absorption spectra of DPA in a pH range of 2.0-10.5. We show that the ring breathing mode Raman peak of DPA shifts from 1003 cm(-1) to 1017 cm (-1) and then to 1000 cm(-1) as pH increases from 2 to 5. The relative peak intensities related to the different ionic forms of DPA are used to experimentally derive the pK(a) values (2.3 and 4.8). We observe using UV-vis spectroscopy that the changes in the absorption spectrum of DPA as a function of pH correlate with the changes observed in Raman spectroscopy, and the same pK(a) values are verified. Lastly, using fluorescence spectroscopy and exciting a DPA solution at between 210-330 nm, we observe a shift in fluorescence emission from 375 nm to 425 nm between pH 2 and pH 6 when exciting at 320 nm. Our work shows that the different spectral responses from the three ionic forms of DPA may have to be taken into account in, e.g., spectral analysis and for detection applications. (C) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

We show that the anticipation of COVID-19 vaccines reduces voluntary social distancing. In a large-scale preregistered survey experiment with a representative sample, we study whether providing information about the safety, effectiveness, and availability of COVID- 19 vaccines affects compliance with public health guidelines. We find that vaccine information reduces peoples’ voluntary social distancing, adherence to hygiene guidelines, and their willingness to stay at home. Vaccine information induces people to believe in a swifter return to normal life and puts their vigilance at ease. The results indicate an important behavioral drawback of the successful vaccine development: An increased focus on vaccines can lead to bad health behaviors and accelerate the spread of the virus. The results imply that, as vaccinations start and the end of the pandemic feels closer, existing policies aimed at increasing social distancing will be less effective and stricter policies might be required.

This paper reports the results of a choice experiment designed to estimate the private welfare costs of stay-at-home policies during the COVID-19 pandemic. The study is conducted on a large and representative sample of the Swedish population. The results suggest that the welfare cost of a one-month stay-at-home policy, restricting non-working hours away from home, amounts to 9.1 percent of Sweden's monthly GDP. Moreover, we find that stricter and longer lockdowns are disproportionately more costly than lenient ones, indicating that strict policies are cost-effective only if they are much more successful in slowing the spread of the disease.

Collecting data under field conditions for forensic investigations of chemical warfare agents calls for the use of portable instruments. In this study, a set of aged, crude preparations of sulfur mustard were characterized spectroscopically without any sample preparation using handheld Raman and portable IR instruments. The spectral data was used to construct Random Forest multivariate models for the attribution of test set samples to the synthetic method used for their production. Colored and fluorescent samples were included in the study, which made Raman spectroscopy challenging although fluorescence was diminished by using an excitation wavelength of 1064 nm. The predictive power of models constructed with IR or Raman data alone, as well as with combined data was investigated. Both techniques gave useful data for attribution. Model performance was enhanced when Raman and IR spectra were combined, allowing correct classification of 19/23 (83%) of test set spectra. The results demonstrate that data obtained with spectroscopy instruments amenable for field deployment can be useful in forensic studies of chemical warfare agents.

This paper studies the role of strategic uncertainty in the Nash demand game. A player’s uncertainty about another player’s strategy is modeled as an atomless probability distribution over that player’s strategy set. A strategy profile is robust to strategic uncertainty if it is the limit, as uncertainty vanishes, of some sequence of strategy profiles in which every player’s strategy is optimal under his or her uncertainty about the others (Andersson et al., 2014). In the context of the Nash demand game, we show that robustness to symmetric (asymmetric) strategic uncertainty singles out the (generalized) Nash bargaining solution. The least uncertain party obtains the bigger share.

The metabolome, which is the final down-stream global product of metabolic processes in organisms, is not sufficiently described in multiple myeloma (MM) patients. The aim of this study was, therefore, to study the serum metabolomic profile using proton nuclear magnetic resonance (1H-NMR) spectroscopy, and its relationship to clinical characteristics and patient outcome. Serum samples, which were taken at diagnosis, from 201 MM patients who underwent high-dose melphalan followed by autologous stem cell transplantation as the first-line therapy, were analyzed. We found that the metabolomic profile differed between patients with different MM International Staging System (ISS) stages. The profile revealed increased levels of cholesterol, phospholipids, high-density lipoprotein, low-density lipoprotein, apolipoproteins A1 and A2, valine, and leucine in ISS I patients compared with ISS III patients. The metabolomic profile also differed between patients with IgA and IgG paraproteins, predominantly because of higher levels of high- and low-density lipoprotein subfractions in IgA patients. The exact pathway of metabolism leading to accumulation of these metabolites is still elusive, but this study indicates an area of interest for further investigation in the search for new therapy targets and prognostic markers for this disease.

Acts of terror and warfare threats are challenging tasks for defense agencies around the world and of growing importance to security conscious policy makers and the general public. Explosives and chemical warfare agents are two of the major concerns in this context, as illustrated by the recent Boston Marathon bombing and nerve gas attacks on civilians in the Middle East. To prevent such tragic disasters, security personnel must be able to find, identify and deactivate the threats at multiple locations and levels. This involves major technical and practical challenges, such as detection of ultra-low quantities of hazardous compounds at remote locations for anti-terror purposes and monitoring of environmental sanitation of dumped or left behind toxic substances and explosives. Surface-enhanced Raman scattering (SERS) is one of todays most interesting and rapidly developing methods for label-free ultrasensitive vibrational "fingerprinting" of a variety of molecular compounds. Performance highlights include attomolar detection of TNT and DNT explosives, a sensitivity that few, if any, other technique can compete with. Moreover, instrumentation needed for SERS analysis are becoming progressively better, smaller and cheaper, and can today be acquired for a retail price close to 10,000 US$. This contribution aims to give a comprehensive overview of SERS as a technique for detection of explosives and chemical threats. We discuss the prospects of SERS becoming a major tool for convenient in-situ threat identification and we summarize existing SERS detection methods and substrates with particular focus on ultra-sensitive real-time detection. General concepts, detection capabilities and perspectives are discussed in order to guide potential users of the technique for homeland security and anti-warfare purposes.

Here we rationally evaluate surface-enhanced Raman spectroscopy (SERS) substrates in terms of limit of detection (LOD), limit of identification (LOI) and dynamic range for ten common narcotic drug analytes. The drugs were amphetamine, cocaine, methadone, diazepam, methylphenidate, oxazepam, tramadol, morphine, buprenorphine and 6-monoacetylmorphine. A Raman microscope system was complemented with portable instrumentation, both in conjunction with commercial SERS substrates, and, by vibrational peak assignments, the functionality of substrates and pureness of samples was ensured. The dynamic range is explored qualitatively by concentration series measurements, where the Langmuir adsorption isotherm provided good fits. Moreover, an output fit parameter, the inverse of Langmuir constant, was found to roughly scale with LOD and can therefore be helpful in SERS substrate evaluations. Four different statistical methodologies were tested to estimate LOD: (i) a general formula to calculate a one-sided prediction interval for the mean value of blanks (LOD B ), (ii–iii) calculated from a one-sided prediction interval (at significance level 0.05) of a linear regression line, where the obtained limit of detection in the signal domain was sometimes outside the linear concentration range, which is why the corresponding concentration was calculated from (ii) a linear calibration curve (LOD LR ) and (iii) a non-linear calibration curve (LOD NR ), and (iv) using receiver operating characteristic (ROC) curves to estimate LOD ROC . Here, a new optimization approach was introduced for LOD ROC estimation, based on interpolation and thus better suited to handle a few data points spanning a large concentration range. LOI was assessed by discriminant analysis of partial least squares (PLS-DA) classification for seven of the drug compounds using PLS-DA, and the extracted LOIs were found to be higher than the LODs and were varying with respect to accuracy of the model which is strongly correlated to the probability of false positive detection that can be accepted.

There have been concerns about serious infusion-related adverse drug reactions (ADR) with rituximab in chronic lymphocytic leukemia (CLL). We therefore conducted an observational trial in which CLL patients planned for rituximab-containing therapy were eligible. Ninety-six patients from 19 centers were enrolled. The most common regimen was rituximab, fludarabine and cyclophosphamide. Fifty-six patients experienced ADR during rituximab infusion. Reactions ≥ grade 3 occurred in five patients and no cases of tumor lysis syndrome were recorded. Despite a high number of circulating tumor cells few severe ADR were noted. Thus, rituximab-containing regimens can be considered safe for CLL patients in general practice.

We introduce a criterion for robustness to strategic uncertainty in games with continuum strategy sets. We model a player's uncertainty about another player's strategy as an atomless probability distribution over that player's strategy set. We call a strategy profile robust to strategic uncertainty if it is the limit, as uncertainty vanishes, of some sequence of strategy profiles in which every player's strategy is optimal under his or her uncertainty about the others. When payoff functions are continuous we show that our criterion is a refinement of Nash equilibrium and we also give sufficient conditions for existence of a robust strategy profile. In addition, we apply the criterion to Bertrand games with convex costs, a class of games with discontinuous payoff functions and a continuum of Nash equilibria. We show that it then selects a unique Nash equilibrium, in agreement with some recent experimental findings.

It is unknown how testing with high-sensitivity troponin (hs-cTnT) compared with conventional troponin (cTn) in the emergency department (ED) is associated with outcomes in chest pain patients. In an observational cohort study we included all patients who sought medical attention for chest pain

The system, trans-1,2-bis (4-pyridyl) ethylene (BPE) on a Au substrate, is used to examine the applicability of cluster approximations for chemically enhanced molecule-surface Raman spectra. Differ ...

Nerve agents such as tabun, cyclosarin and Russian VX inhibit the essential enzyme acetylcholinesterase (AChE) by organophosphorylating the catalytic serine residue. Nucleophiles, such as oximes, are used as antidotes as they can reactivate and restore the function of the inhibited enzyme. The oxime HI-6 shows a notably low activity on tabun adducts but can effectively reactivate adducts of cyclosarin and Russian VX. To examine the structural basis for the pronounced substrate specificity of HI-6, we determined the binary crystal structures of Mus musculus AChE (mAChE) conjugated by cyclosarin and Russian VX and found a conformational mobility of the side chains of Phe338 and His447. The interaction between HI-6 and tabun-adducts of AChE were subsequently investigated using a combination of time resolved fluorescence spectroscopy and X-ray crystallography. Our findings show that HI-6 binds to tabun inhibited Homo sapiens AChE (hAChE) with an IC50 value of 300μM and suggest that the reactive nucleophilic moiety of HI-6 is excluded from the phosphorus atom of tabun. We propose that a conformational mobility of the side-chains of Phe338 and His447 is a common feature in nerve-agent adducts of AChE. We also suggest that the conformational mobility allow HI-6 to reactivate conjugates of cyclosarin and Russian VX while a reduced mobility in tabun conjugated AChE results in steric hindrance that prevents efficient reactivation.

The structure and photocatalytic activity of Zr doped TiO 2 nanocrystallites with a varying Zr content between 0 and 15 wt% prepared by an efficient and environmentally benign method has been studied by vibrational spectroscopy, TEM and XRD. It is shown that the presence of Zr 4+ ions stabilizes the anatase structure and delays phase transformation to rutile upon annealing as well as retarding grain coarsening. All TiO 2 samples up to 13 wt% Zr doping concentration show better or similar photoreactivity compared to P25 (Degussa) for decomposition of adsorbed 2-chloroethyl ethyl sulphide (CEES) and dimethyl methylphosphonate (DMMP) in synthetic air at room temperature. The most efficient sample for photodegradation of both CEES and DMMP is shown to be titania doped with 6.8 wt% Zr. The photodegradation of CEES is faster than DMMP under the same experimental conditions. On the undoped TiO 2 sample urea residues are detected spectroscopically. Much less is detected on the Zr doped samples. Mode resolved in situ FTIR surface spectroscopy enables distinction of CEES or DMMP, decomposition products as well as the influence of residues from the particle synthesis. This facilitates extraction of intra-comparable reaction rates. Possible explanations for the improved reactivity of the Zr doped titania are discussed.

Pure titania and titania doped with Zn 2+ were prepared by homogeneous hydrolysis in aqueous solution with urea and thioacetamide as precipitating agents. The materials were characterized by XRD, TEM, BET and BJH analysis, which show microporous, nanaocrytsalline anatase phase titania in the size range 4–5 nm and specific surface area 200–500 m 2 /g. Adsorption and photocatalytic decomposition of 2-chloroethyl ethyl sulfide (CEES) was measured on dry and water pre-covered titania surfaces, respectively. Illumination with UV light leads to rapid decomposition of CEES on all samples resulting in formation of surface bound ethoxy, chloro ethoxy, aldehydes, acetone and carboxylates. Volatile sulphur moieties (S O) and isocyanate (Ti-NCO) are observed which is related to the synthesis methods employed. A procedure for removing residual synthesis products from the particles was devised and the intrinsic photodegradation rate was determined on the purified samples and compared with the as prepared samples. The photodegradation rate is notable higher for the purified TiO 2 nanoparticles prepared by the urea route with respect to the “as prepared”. In the case of the Zn doped TiO 2 samples a diminution in photodegradation rate is observed after purification. The results are correlated with the amount of volatile residual synthesis products present on the different particles. All materials have comparable or higher photo-reactivity than P25 (Degussa). On a humidified surface, the effects from synthesis residues, in particular volatile sulphur moieties, are reduced due to reactions with water and improved photoreaction rates for all samples are observed.

This paper analyzes the role of patience in a repeated Bertrand duopoly where firms bargain over which collusive price and market share to implement. It is shown that the least patient firm's market share is not monotone in its own discount factor.

In this report we have evaluated the potential of using fluorescence/Förster resonance energy transfer (FRET) in a competitive immunosensor for continuous monitoring of the carbohydrate hapten maltose. The cyanine dyes Cy5 and Cy5.5 were used as a donor-acceptor pair by conjugation to maltose-labeled bovine serum albumin (BSA) and the monoclonal antibody IgG 39.5, giving Cy5-BSA-maltotriitol (3.1/1/18) and Cy5.5-mAb39.5 (2.2/1), respectively. This antibody with weak affinity towards maltose showed full reversibility to both the free maltose and the maltose-labeled conjugate. It allowed us to measure continuously the maltose content by monitoring the FRET signal change over time due to displacement of Cy5-BSA-maltotriitol from Cy5.5-mAb39.5 inside a semipermeable capsule. A near 22% total increase was seen in the fluorescence intensity ratio I(670)/I(700) in the presence of maltose, with a calculated EC(50)=1.87+/-0.13 mM (R(2)=0.9984) from the sigmoidal dose-response curve at 25 degrees C. Specificity of the immunosensor was shown with the structural analog to maltose, cellobiose, and it generated no detectable response. A minor drift in the sensor baseline was seen with 0.4% per 24 h, which was in the same magnitude as the signal-to-noise ratio, during the 4 weeks of measurements. The immunosensor was applied to crude samples of oat drinks for direct quantification of the maltose content. Overall, this work demonstrates the potential to use an immunosensor based on weakly binding antibodies and FRET technology for remote and non-invasive carbohydrate monitoring.

Weak Renegotiation-Proofness (WW) singles out marginal cost pricing as a unique pure-strategy equilibrium of the infinitely repeated Bertrand duopoly. We show that, with a discrete strategy space, WRP does not eliminate any relevant subgame perfect equilibrium outcome. (c) 2006 Elsevier B.V. All rights reserved.

Mixtures of equal amounts of the erythro and the threo forms of the β-O-4 lignin model compound 1-(3,4-dimethoxyphenyl)-2-(2- methoxyphenoxy)-1,3-propanediol were oxidized with different ligninolytic enzymes and non-enzymic oxidants. The oxidants included cerium(IV) ammonium nitrate (CAN), Fenton’s reagent, lead(IV) tetraacetate (LTA), laccase, laccase–mediator systems (based on the mediators ABTS, HBT, TEMPO, and VLA), and lignin peroxidase. The stereo-preference of the different oxidants was compared based on analyses of remaining substrate using HPLC and UV-diode array detector or 1H NMR spectroscopy. Fenton’s reagent was the only oxidant tested that did not show preferential degradation of either the erythro or the threo form. CAN, LTA and lignin peroxidase preferentially oxidized the threo form. The stereo-preference of the laccase–mediator systems depended on the mediator. Oxidation mediated by HBT, TEMPO or VLA resulted in a preferential degradation of the threo form. Laccase/ABTS was the only system tested that showed preferential oxidation of the erythro form. The stereo-preference of the oxidants is discussed based on their redox potentials and their classification as outer-sphere and inner-sphere oxidants.

Here we report on a novel method for the direct in situ measurement of specific isomeric forms of the anticoagulant warfarin using time correlated single-photon counting (TCSPC) spectroscopy in conjunction with synthetic Sudlow I binding site receptors. The method is highly robust over the clinically significant concentration range, and demonstrates the potential of the binding site mimics in conjunction with the spectroscopic strategy employed here for the determination of this important pharmaceutical in clinical or even environmental samples.

The nearly exponential growth in the molecular imprinting literature has to a large extent been fuelled by an increasing awareness of the potential of molecular imprinting based technologies. Despite the acceptance of the technique by cognate disciplines and the demonstration of its usefulness in a number of enabling technologies, relatively little is known about the molecular level events underlying the imprinting process and subsequent recognition events. What rules govern imprint formation? Can we use such rules to rationally design molecularly imprinted polymers?

We study persuasion effects in experimental ultimatum games and find that Proposers' payoffs significantly increase if, along with offers, they can send messages which Responders read before deciding. Higher payoffs are driven by both lower offers and higher acceptance rates.

We study risk taking on behalf of others, both with and without potential losses. A large-scale incentivized experiment is conducted with subjects randomly drawn from the Danish population.On average, decision makers take the same risks for other people as for themselves when losses are excluded. In contrast, when losses are possible, decisions on behalf of others are more risky. Using structural estimation, we show that this increase in risk stems from a decrease in loss aversion when others are affected by their choices.

The energy transfer from the carotenoid okenone to bacteriochlorophyll a (Bchl a) in the light harvesting complex B800–830 and chromatophores of Chromatium purpuratum was studied by steady-state fluorescence and fermtosecond transient absorption spectroscopy. By comparing the fluorescence excitation and the absorption spectra of the B800–830 antenna complex the total energy transfer efficiency of the okenone-to-Bchl a transfer was determined to 95 ± 5%. A fast (

Fluorescence from a highly substituted triene, called mini-3, studied at cryogenic temperatures, originates from the lowest excited state (S 1 ). Compared to the longer compounds homologous to all-trans-β-carotene, the emission is more Stokes-shifted. Another contrast is that the measured fluorescence quantum yield of mini-3 shows a distinct temperature/viscosity dependence: in 3-methylpentane decreasing from 0.61 at 77 K to 0.047 at 110 K. In room-temperature liquids it is virtually non-fluorescent. The discrepancies between mini-3 and the longer mini-carotenes are best explained by the involvement of out-of-plane vibrational modes in the coupling between S 1 and S 0 in mini-3, while only the CC stretching vibrations act as accepting and promoted modes in the longer ones. It is likely that the low-frequency modes in mini-3 are caused by a nonplanar equilibrium conformation, probably caused by steric hindrance. An Arrhenius plot resulted in an activation energy of 610 ± 200 cm −1 , probably mainly governed by solvent viscosity. The fluorescence excitation anisotropy ( r s ) is about 0.39, indicating that the absorption and emission transition dipoles are parallel.

This paper considers the sealed bid and ascending auction, which both identifies the minimum Walrasian equilibrium prices and where truthful preference revelation constitutes an equilibrium. Even though these auction formats share many theortical properties, there are behavioral aspects that are not easily captured. To explore this issue in more detail, this paper experimentally investigates what role the design of the auction format has for its outcome. The results suggest that the sealed bid mechanism performs weakly better in all of investigated measures (consistent reporting, efficiency etc.). In addition, we find that the performance of the ascending auction is increasing over time, whereas the sealed bid auction shows no such tendency.

It is well known that communication often serves as a facilitator for cooperation in static games. Yet, communication can serve entirely different purposes in dynamic settings as communication during the game may work as a means for renegotiation, potentially undermining the credibility of cooperative strategies. To explore this issue, this paper experimentally investigates cooperation and non-binding communication in a two-stage game. More specifically, two treatments are considered: one with only pre-play communication and one where subjects can also communicate intra-play between the stages of the game. The results highlight a nontrivial difference concerning the effects of pre-play communication between the two treatments. Pre-play communication only has a significant impact on cooperation when no intra-play communication is possible. The results suggest that the credibility of pre-play messages may depend crucially on future communication opportunities.

We model a player’s uncertainty about other players’ strategy choices as smooth probability distributions over their strategy sets. We call a strategy profile (strictly) robust to strategic uncertainty if it is the limit, as uncertainty vanishes, of some sequence (all sequences) of strategy profiles, in each of which every player’s strategy is optimal under under his or her uncertainty about the others. We derive general properties of such robustness, and apply the definition to Bertrand competition games and the Nash demand game, games that admit infinitely many Nash equilibria. We show that our robustness criterion selects a unique Nash equilibrium in the Bertrand games, and that this agrees with recent experimental findings.

The role of the 11Bu and 21Ag singlet states of carotenoids in the singlet-singlet energy transfer process from carotenoids to chlorophylls (their photosynthetic light-harvesting function is discussed. The 1Bu state was investigated by measuring its fluorescence, while the 21Ag state was monitored in picosecond ground state depletion/recovery experiments. The data presented suggest that energy transfer occurs from the 21Ag state.

Fluorescence and fluorescence excitation spectra of 77 K glasses and room temperature solutions of a series of compounds homologous to trans-β-carotene with 5 (mini-5), 7 (mini-7), 9 (mini-9) and 11 (β-carotene) conjugated double bonds were measured. Dual emission of mini-5, 7 and 9 were observed at 77 K. For mini-5 and 7 the emission was largely dominated by a Stokes-shifted 21A-g(S1) → 11A-g(S0) emission, while the 11B+u(S2) → 11A- g emission was dominating in mini-9 and β-carotene. From the 77 K absorption and fluorescence spectra of mini-5, 7 and 9 the 0-0 excitation energies of S0 → S2 (E(S2)) and S0 → S1 (E(S1)) transitions were estimated. From the shortest to the longest carotene E(S 2 was 29 400±500, 24 900±200 and 21 900±100 cm-, respectively, and for E(S1) it was 22 700±1000, 19 900±1000 and 16 600±1000 cm-1. E(S1) of β-carotene is extrapolated from the energies of the min-carotenes to be located at 14 500±1000 cm-1, which is significantly lower than the value found earlier by Raman spectroscopy (17 230±100 cm-1). The trend for linear (un)substituted polyenes, that the energy gap (ΔE) between S2 and S1 increases with the length of conjugation, was not observed for the mini-carotenes. For mini-5 ΔE is about 2000 cm-1 larger than for the unsubstituted polyene decapentaene, while ΔE for mini-7 agrees well with (un)substituted heptaene. In n-hexane at room temperature the fluorescence quantum yields of the S1 → S0 emission (φ1) for mini-5 and 7 were to be (7±3)×10-3 and (8±4)×10-4, respectively, and the S2 → S0 emission (φ2) for mini-9 and β-carotene they were (1.0±0.5)×10-4 and (2±1)×10-4, respectively. The estimated yield ratio (φ1/φ2) of the compounds decreased from ∾ 7000 for mini-5 to ∾ 0.1 for mini-9. For mini-9 in n-hexane, no emission from the S1 state was observed while the emission showed up in carbon disulfide, which is explained by the smaller ΔE of mini-9 in carbon disuifide. The fluorescence lifetime of 21A-g of mini-5 in n-hexane at room temperature was found, by single-photon counting technique, to be (2.0±0.2) ns.