Combinatorial operad actions on cochains

A classical E-infinity operad is formed by the bar construction of the symmetric groups. Such an operad has been introduced by M. Barratt and P. Eccles in the context of simplicial sets in order to have an analogue of the Milnor FK-construction for infinite loop spaces. The purpose of this article is to prove that the associative algebra structure on the normalized cochain complex of a simplicial set extends to the structure of an algebra over the Barratt-Eccles operad. We also prove that differential graded algebras over the Barratt-Eccles operad form a closed model category. Similar results hold for the normalized Hochschild cochain complex of an associative algebra. More precisely, the Hochschild cochain complex is acted on by a suboperad of the Barratt-Eccles operad which is equivalent to the classical little squares operad.Comment: 46 pages. Final versio

Isosexual precocious pseudopuberty during mitotane treatment in a child with adrenocortical carcinoma:A case report

Background Mitotane is employed as adjuvant therapy in managing adrenocortical carcinoma in pediatric patients. While various adverse effects, such as estrogen-like manifestations, are well-documented in adults, there is limited knowledge regarding pediatric-specific toxicity. This report details an uncommon case of isosexual precocious pseudopuberty induced during childhood due to the estrogen-like effects of mitotane. Case report A 2.8-year-old female diagnosed with adrenocortical carcinoma (pT4 pN0 M0) underwent adjuvant treatment with mitotane and cytotoxic chemotherapy following incomplete resection (tumor stage III). Approximately eight months into mitotane treatment, she exhibited signs of puberty (Tanner stage 2), including progressive breast development, uterine enlargement, vaginal discharge, and an advancement of bone age by nearly two years. Gonadotrophin-dependent puberty and endogenous estrogen production were ruled out. The precocious pseudopuberty was attributed to previously reported estrogen-like effects of mitotane therapy. Subsequent administration of the aromatase inhibitor anastrozole in combination with mitotane led to a reduction in clinical signs of puberty. Conclusion Monitoring for estrogen-like effects of mitotane is crucial, particularly in pre-pubertal children, to avert potentially irreversible changes associated with precocious pseudopuberty. Aromatase inhibitors may serve as a prompt therapeutic option, enabling the continuation of mitotane treatment

Amphiphilic beads as depots for sustained drug release integrated into fibrillar scaffolds

Native extracellular matrix (ECM) is a complex fibrous structure loaded with bioactive cues that affects the surrounding cells. A promising strategy to mimicking native tissue architecture for tissue engineering applications is to engineer fibrous scaffolds using electrospinning. By loading appropriate bioactive cues within these fibrous scaffolds, various cellular functions such as cell adhesion, proliferation and differentiation can be regulated. Here, we report on the encapsulation and sustained release of a model hydrophobic drug (dexamethasone (Dex)) within beaded fibrillar scaffold of poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT), a polyether-ester multiblock copolymer to direct differentiation of human mesenchymal stem cells (hMSCs). The amphiphilic beads act as depots for sustained drug release that is integrated into the fibrillar scaffolds. The entrapment of Dex within the beaded structure results in sustained release of the drug over the period of 28days. This is mainly attributed to the diffusion driven release of Dex from the amphiphilic electrospun scaffolds. In vitro results indicate that hMSCs cultured on Dex containing beaded fibrillar scaffolds exhibit an increase in osteogenic differentiation potential, as evidenced by increased alkaline phosphatase (ALP) activity, compared to the direct infusion of Dex in the culture medium. The formation of a mineralized matrix is also significantly enhanced due to the controlled Dex release from the fibrous scaffolds. This approach can be used to engineer scaffolds with appropriate chemical cues to direct tissue regenerationAKG, SMM, LM and AK conceived the idea and designed the experiments. AKG and SMM fabricated electrospun scaffolds and performed the structural (SEM, FTIR), mechanical, and in vitro studies. AAK and AKGperformedDex release study. AKGand AP performed thermal analysis. AKG analyzed experimental data. AKG, SMM, LMand AK wrote the manuscript. ADL and CvB provided the polymers and corrected the manuscript. AKK, AP, MG and RLR revised the paper. All authors discussed the results and commented on the manuscript. Authors would like to thank Shilpaa Mukundan, Poornima Kulkarni and Dr. Arghya Paul for help with image analysis, drug release modeling and technical discussion respectively. AKG would like to thank Prof. Robert Langer for access to equipment and acknowledge financial support from MIT Portugal Program (MPP-09Call-Langer-47). SMMthanks the Portuguese Foundation for Science and Technology (FCT) for the personal grant SFRH/BD/42968/2008 (MIT-Portugal Program). This research was funded by the office of Naval Research Young National Investigator Award (AK), the Presidential Early Career Award for Scientists and Engineers (PECASE) (AK), the NIH (EB009196; DE019024; EB007249; HL099073; AR057837), the National Science Foundation CAREER award (DMR 0847287; AK), and the Dutch Technology Foundation (STW # 11135; LM, CvB, and AD)

Jet energy measurement with the ATLAS detector in proton-proton collisions at root s=7 TeV

The jet energy scale and its systematic uncertainty are determined for jets measured with the ATLAS detector at the LHC in proton-proton collision data at a centre-of-mass energy of √s = 7TeV corresponding to an integrated luminosity of 38 pb-1. Jets are reconstructed with the anti-kt algorithm with distance parameters R=0. 4 or R=0. 6. Jet energy and angle corrections are determined from Monte Carlo simulations to calibrate jets with transverse momenta pT≥20 GeV and pseudorapidities {pipe}η{pipe}<4. 5. The jet energy systematic uncertainty is estimated using the single isolated hadron response measured in situ and in test-beams, exploiting the transverse momentum balance between central and forward jets in events with dijet topologies and studying systematic variations in Monte Carlo simulations. The jet energy uncertainty is less than 2. 5 % in the central calorimeter region ({pipe}η{pipe}<0. 8) for jets with 60≤pT<800 GeV, and is maximally 14 % for pT<30 GeV in the most forward region 3. 2≤{pipe}η{pipe}<4. 5. The jet energy is validated for jet transverse momenta up to 1 TeV to the level of a few percent using several in situ techniques by comparing a well-known reference such as the recoiling photon pT, the sum of the transverse momenta of tracks associated to the jet, or a system of low-pT jets recoiling against a high-pT jet. More sophisticated jet calibration schemes are presented based on calorimeter cell energy density weighting or hadronic properties of jets, aiming for an improved jet energy resolution and a reduced flavour dependence of the jet response. The systematic uncertainty of the jet energy determined from a combination of in situ techniques is consistent with the one derived from single hadron response measurements over a wide kinematic range. The nominal corrections and uncertainties are derived for isolated jets in an inclusive sample of high-pT jets. Special cases such as event topologies with close-by jets, or selections of samples with an enhanced content of jets originating from light quarks, heavy quarks or gluons are also discussed and the corresponding uncertainties are determined. © 2013 CERN for the benefit of the ATLAS collaboration

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal

Observation of associated near-side and away-side long-range correlations in √sNN=5.02 TeV proton-lead collisions with the ATLAS detector

Two-particle correlations in relative azimuthal angle (Δϕ) and pseudorapidity (Δη) are measured in √sNN=5.02  TeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1  μb-1 of data as a function of transverse momentum (pT) and the transverse energy (ΣETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Δη|<5) “near-side” (Δϕ∼0) correlation that grows rapidly with increasing ΣETPb. A long-range “away-side” (Δϕ∼π) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ΣETPb, is found to match the near-side correlation in magnitude, shape (in Δη and Δϕ) and ΣETPb dependence. The resultant Δϕ correlation is approximately symmetric about π/2, and is consistent with a dominant cos⁡2Δϕ modulation for all ΣETPb ranges and particle pT

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal