Identification and rejection of pile-up jets at high pseudorapidity with the ATLAS detector

The rejection of forward jets originating from additional proton–proton interactions (pile-up) is crucial for a variety of physics analyses at the LHC, including Standard Model measurements and searches for physics beyond the Standard Model. The identification of such jets is challenging due to the lack of track and vertex information in the pseudorapidity range |η| > 2.5. This paper presents a novel strategy for forward pile-up jet tagging that exploits jet shapes and topological jet correlations in pile-up interactions. Measurements of the per-jet tagging efficiency are presented using a data set of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of 13 TeV collected with the ATLAS detector. The fraction of pile-up jets rejected in the range 2.5 < |η| < 4.5 is estimated in simulated events with an average of 22 interactions per bunch-crossing. It increases with jet transverse momentum and, for jets with transverse momentum between 20 and 50 GeV, it ranges between 49% and 67% with an efficiency of 85% for selecting hard-scatter jets. A case study is performed in Higgs boson production via the vector-boson fusion process, showing that these techniques mitigate the background growth due to additional proton–proton interactions, thus enhancing the reach for such signatures

Parosteal lipoma as a rare cause of peripheral neuropathy and local irritation: A report of 12 cases

Objective: The aim of this study was to evaluate the clinical features and functional results of patientswith parosteal lipomas.Methods: A total of 12 patients (8 females and 4 males; mean age: 45 (10e62) years) with parosteallipomas who were treated between April 1986 and April 2014, were included into the study. The medicalrecords of the patients were reviewed to analyze the clinical features and functional results of thepatients.Results: Of the 12 lipomas, 5 were localized in the proximal arm, 4 in the forearm, 1 in the distal arm, 1 inthe distal thigh and 1 in the distal tibia. All patients presented with a progressive, slow-growing massthat was associated with thumb extension weakness in 1 case, and brachialgia-like symptoms in 1 case.Plain radiographs showed a juxtacortical mass in all cases and irregular ossiŞcation in 3 cases. In all cases,marginal excision was performed and no clinical recurrence was observed after a mean follow-up of 16months.Conclusion: Parosteal lipomas are uncommon tumors that can be diagnosed with their characteristicradiological features. Parosteal lipomas occurring in the proximal radius may easily cause paralysis of theposterior interosseous nerve or muscle weakness.Level of Evidence: Level IV, Therapeutic study.Objective: The aim of this study was to evaluate the clinical features and functional results of patientswith parosteal lipomas.Methods: A total of 12 patients (8 females and 4 males; mean age: 45 (10e62) years) with parosteallipomas who were treated between April 1986 and April 2014, were included into the study. The medicalrecords of the patients were reviewed to analyze the clinical features and functional results of thepatients.Results: Of the 12 lipomas, 5 were localized in the proximal arm, 4 in the forearm, 1 in the distal arm, 1 inthe distal thigh and 1 in the distal tibia. All patients presented with a progressive, slow-growing massthat was associated with thumb extension weakness in 1 case, and brachialgia-like symptoms in 1 case.Plain radiographs showed a juxtacortical mass in all cases and irregular ossiŞcation in 3 cases. In all cases,marginal excision was performed and no clinical recurrence was observed after a mean follow-up of 16months.Conclusion: Parosteal lipomas are uncommon tumors that can be diagnosed with their characteristicradiological features. Parosteal lipomas occurring in the proximal radius may easily cause paralysis of theposterior interosseous nerve or muscle weakness.Level of Evidence: Level IV, Therapeutic study

Microwave-assisted methylation of dihydroxybenzene derivatives with dimethyl carbonate

Using a focused microwave reactor, methylation with dimethyl carbonate (DMC) of 1,2- and 1,4-dihydroxybenzene derivatives, found in the product spectrum of lignin depolymerisation, leads to the respective aromatic bis-methyl ethers with excellent isolated yields. Stoichiometric as well as catalytic amounts of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) are effective for the bis-methylation of these dihydroxybenzenes at relatively mild temperatures (160-190 degrees C). Conversion of resorcinol (1,3-dihydroxybenzene) under similar conditions leads to a mixture of 1,3-dimethoxybenzene and methyl 2,4-dimethoxybenzoate. The unusual reactivity of resorcinol's phenyl ring towards DMC can be explained by the synergic effect of its two strongly activating ortho/para directing groups