The Research Institute for Fragrance Materials' human repeated insult patch test protocol

Abstract With implementation of the dermal sensitization QRA approach for fragrance ingredients, IFRA/RIFM are recommending use of the RIFM standard human repeated insult patch test (HRIPT) protocol for generation of confirmatory human data for the induction of dermal sensitization in a normal human population. Details of this standard HRIPT protocol are provided in this paper. The study protocol consists of two phases-Induction and Challenge. In the Induction phase, patches treated with fragrance ingredients in 75% diethyl phthalate/25% ethanol are applied to backs of volunteers for 24 h. Following patch removal there is a 24-h rest period and volunteers are patched again at the same site. This procedure is repeated to achieve 9 applications over a 3-week period. There is an approximate 2-week rest period followed by a Challenge phase of a single 24-h patch application of test article applied to a naïve site on the back. Skin reactions at the naïve site observed at Challenge may be suggestive of dermal sensitization, and a Rechallenge is performed to confirm the nature of the reactivity. This study is designed to confirm the No-Observed-Effect-Level for induction of dermal sensitization in a normal human population

A pilot study aimed at finding a suitable eugenol concentration for a leave-on product for use in a repeated open application test.

Background. Knowledge of sensitization and elicitation thresholds and the time-dose relationship for elicitation of contact dermatitis is important in order to provide safe products for consumers. Objective. Since previous studies performed with eugenol had showed negative results in a repeat open application study (ROAT) study, we wanted to perform a ROAT with higher concentration (maximum allowed) and longer ROAT. Materials. 5 volunteers previously tested positive to eugenol were studied. They performed a ROAT test for maximum 4 weeks with four different solutions. Results. Four of five reacted to the maximum concentration of eugenol in the ROAT. Conclusion. In patients sensitized to eugenol, with the maximum allowed concentration of eugenol and given a prolonged ROAT (4 weeks), there is a clear risk of elicitating an allergic contact dermatitis

Does the New Standard for Eugenol Designed to Protect Against Contact Sensitization Protect Those Sensitized From Elicitation of the Reaction?

Background: Potential fragrance allergens used in daily products should have a concentration limited to levels that are at, or below, acceptable exposure levels based on the quantitative risk assessment for the induction of dermal sensitization. To date, there are insufficient data to discern any quantitative relationship between induction and elicitation concentrations for fragrance ingredients that have a potential for dermal sensitization. When available, these data should be used to confirm the effectiveness of quantitative risk assessment-based risk management procedures. Objective: In this study, the relationship between the allergen concentration and the time to elicit allergic contact dermatitis in eugenol-sensitized patients was studied. The products used to elicit allergic contact dermatitis had a concentration of eugenol that was equal to, or below, the International Fragrance Association standard. Methods: Volunteers with and without known sensitization to eugenol were patch tested with various concentrations of eugenol (dilution series) and also underwent repeated open application tests (ROATs). This study model has previously been successfully used with stronger sensitizers. Results: In this study, allergic contact dermatitis, as evidenced by a positive ROAT, could not be elicited by any of the concentrations studied, including in those patients where the patch tests were positive. Conclusions: When tested in a 3-week ROAT at, or below, its current International Fragrance Association Standard, eugenol did not induce reactions even in those known to be sensitized. Whether this represents a false-negative result for a weak allergen is unknown

Direct observation of the dead-cone effect in quantum chromodynamics

The direct measurement of the QCD dead cone in charm quark fragmentation is reported, using iterative declustering of jets tagged with a fully reconstructed charmed hadron

Direct observation of the dead-cone effect in quantum chromodynamics

At particle collider experiments, elementary particle interactions with large momentum transfer produce quarks and gluons (known as partons) whose evolution is governed by the strong force, as described by the theory of quantum chromodynamics (QCD) [1]. The vacuum is not transparent to the partons and induces gluon radiation and quark pair production in a process that can be described as a parton shower [2]. Studying the pattern of the parton shower is one of the key experimental tools in understanding the properties of QCD. This pattern is expected to depend on the mass of the initiating parton, through a phenomenon known as the dead-cone effect, which predicts a suppression of the gluon spectrum emitted by a heavy quark of mass m and energy E, within a cone of angular size m/E around the emitter [3]. A direct observation of the dead-cone effect in QCD has not been possible until now, due to the challenge of reconstructing the cascading quarks and gluons from the experimentally accessible bound hadronic states. Here we show the first direct observation of the QCD dead-cone by using new iterative declustering techniques [4, 5] to reconstruct the parton shower of charm quarks. This result confirms a fundamental feature of QCD, which is derived more generally from its origin as a gauge quantum field theory. Furthermore, the measurement of a dead-cone angle constitutes the first direct experimental observation of the non-zero mass of the charm quark, which is a fundamental constant in the standard model of particle physics.The direct measurement of the QCD dead cone in charm quark fragmentation is reported, using iterative declustering of jets tagged with a fully reconstructed charmed hadron.In particle collider experiments, elementary particle interactions with large momentum transfer produce quarks and gluons (known as partons) whose evolution is governed by the strong force, as described by the theory of quantum chromodynamics (QCD). These partons subsequently emit further partons in a process that can be described as a parton shower which culminates in the formation of detectable hadrons. Studying the pattern of the parton shower is one of the key experimental tools for testing QCD. This pattern is expected to depend on the mass of the initiating parton, through a phenomenon known as the dead-cone effect, which predicts a suppression of the gluon spectrum emitted by a heavy quark of mass $m_{\rm{Q}}$ and energy $E$, within a cone of angular size $m_{\rm{Q}}$/$E$ around the emitter. Previously, a direct observation of the dead-cone effect in QCD had not been possible, owing to the challenge of reconstructing the cascading quarks and gluons from the experimentally accessible hadrons. We report the direct observation of the QCD dead cone by using new iterative declustering techniques to reconstruct the parton shower of charm quarks. This result confirms a fundamental feature of QCD. Furthermore, the measurement of a dead-cone angle constitutes a direct experimental observation of the non-zero mass of the charm quark, which is a fundamental constant in the standard model of particle physics

Σ(1385)± resonance production in Pb–Pb collisions at √sNN = 5.02 TeV

Hadronic resonances are used to probe the hadron gas produced in the late stage of heavy-ion collisions since they decay on the same timescale, of the order of 1 to 10 fm/c, as the decoupling time of the system. In the hadron gas, (pseudo)elastic scatterings among the products of resonances that decayed before the kinetic freeze-out and regeneration processes counteract each other, the net effect depending on the resonance lifetime, the duration of the hadronic phase, and the hadronic cross sections at play. In this context, the Σ(1385)± particle is of particular interest as models predict that regeneration dominates over rescattering despite its relatively short lifetime of about 5.5 fm/c. The first measurement of the Σ(1385)± resonance production at midrapidity in Pb-Pb collisions at sNN−−−√=5.02 TeV with the ALICE detector is presented in this Letter. The resonances are reconstructed via their hadronic decay channel, Λπ, as a function of the transverse momentum (pT) and the collision centrality. The results are discussed in comparison with the measured yield of pions and with expectations from the statistical hadronization model as well as commonly employed event generators, including PYTHIA8/Angantyr and EPOS3 coupled to the UrQMD hadronic cascade afterburner. None of the models can describe the data. For Σ(1385)±, a similar behaviour as K∗(892)0 is observed in data unlike the predictions of EPOS3 with afterburner

Measurement of the lifetime and Λ separation energy of 3ΛH

The most precise measurements to date of the 3ΛH lifetime τ and Λ separation energy BΛ are obtained using the data sample of Pb-Pb collisions at √= 5.02 TeV collected by ALICE at the LHC. The 3ΛH is reconsNN structed via its charged two-body mesonic decay channel (3ΛH→ 3He + π− and the charge-conjugate process). The measured values τ=[253±11 (stat.)±6 (syst.)] ps and BΛ=[102±63 (stat.)±67 (syst.)] keV are compatible with predictions from effective field theories and confirm that the 3ΛH structure is consistent with a weakly-bound system

Measurement of ψ (2S) production as a function of charged-particle pseudorapidity density in pp collisions at √s = 13 TeV and p–Pb collisions at √sNN = 8.16 TeV with ALICE at the LHC

Production of inclusive charmonia in pp collisions at center-of-mass energy of √s = 13 TeV and p–Pb collisions at center-of-mass energy per nucleon pair of √sNN = 8.16 TeV is studied as a function of charged-particle pseudorapidity density with ALICE. Ground and excited charmonium states (J/ψ, ψ(2S)) are measured from their dimuon decays in the interval of rapidity in the center-of-mass frame 2.5 < ycms < 4.0 for pp collisions, and 2.03 < ycms < 3.53 and −4.46 < ycms < −2.96 for p–Pb collisions. The charged-particle pseudorapidity density is measured around midrapidity (|η| < 1.0). In pp collisions, the measured charged-particle multiplicity extends to about six times the average value, while in p-Pb collisions at forward (backward) rapidity a multiplicity corresponding to about three (four) times the average is reached. The ψ(2S) yield increases with the charged-particle pseudorapidity density. The ratio of ψ(2S) over J/ψ yield does not show a significant multiplicity dependence in either colliding system, suggesting a similar behavior of J/ψ and ψ(2S) yields with respect to charged-particle pseudorapidity density. Results for the ψ(2S) yield and its ratio with respect to J/ψ agree with available model calculations