Classical limit for the scattering of Dirac particles in a magnetic field

We present a relativistic quantum calculation at first order in perturbation theory of the differential cross section for a Dirac particle scattered by a solenoidal magnetic field. The resulting cross section is symmetric in the scattering angle as those obtained by Aharonov and Bohm (AB) in the string limit and by Landau and Lifshitz (LL) for the non relativistic case. We show that taking pr_0\|sin(\theta/2)|/\hbar<<1 in our expression of the differential cross section it reduces to the one reported by AB, and if additionally we assume \theta << 1 our result becomes the one obtained by LL. However, these limits are explicitly singular in \hbar as opposed to our initial result. We analyze the singular behavior in \hbar and show that the perturbative Planck's limit (\hbar -> 0) is consistent, contrarily to those of the AB and LL expressions. We also discuss the scattering in a uniform and constant magnetic field, which resembles some features of QCD

Isomeric separation of cannabinoids by UPLC combined with ionic mobility mass spectrometry (TWIM-MS)-Part I

The Cannabis sativa L. plant is rich in a wide variety of cannabinoids. δ9-tetrahydrocannabinol (δ9-THC) is the main chemical compound responsible for its psychoactive effect, and it can be identified as [M+H]+ and [M-H]- ions at m/z 315 and 313, respectively, where M=C21H30O2. However, six other isomeric or isobaric forms of δ9-THC can exist, which makes its unequivocal characterization a challenge. In this work, ultra-high liquid chromatography coupled to traveling wave ion mobility mass spectrometry (UPLC-TWIM-MS) were applied to both electrospray ionization modes (ESI(±)) and used to analyze hashish, marijuana, and parts of the Cannabis Sativa L. plant (flower and leaf). The presence of a complex isomeric mixture of cannabinoids has been identified, and the mixture mainly contains δ9-THC, cannabidiol (CBN-C5 and Mw =310Da), δ9-tetrahydrocannabinolic acid A and B (δ9-THCA-C5 A/B and Mw =358Da) and their isomers. Three isomers of the ions were identified at m/z 315/313, 311, and 357 by using direct infusion ESI-TWIM-MS technique, while higher selectivity was observed in UPLC-ESI-TWIM-MS data, with the maximum isomeric separation between four and five compounds achieved when using single-ion mode (SIM) acquisition. The ions at m/z 311/309, 315/313, 345, and 357 correspond to CBN-C5, δ9-THC, cannabielsioc acid, δ9-THCA-C5 and their isomers, respectively, and they were the main species found. The calculations of collision cross sections were reported for all isomers of cannabinoids and associated with TWIM-MS results

Anaesthesia and airway management in mucopolysaccharidosis

Abstract This paper provides a detailed overview and dis-cussion of anaesthesia in patients with mucopolysacchari-dosis (MPS), the evaluation of risk factors in these patients and their anaesthetic management, including emergency airway issues. MPS represents a group of rare lysosomal storage disorders associated with an array of clinical mani-festations. The high prevalence of airway obstruction and restrictive pulmonary disease in combination with cardio-vascular manifestations poses a high anaesthetic risk to these patients. Typical anaesthetic problems include airway obstruction after induction or extubation, intubation diffi-culties or failure [can’t intubate, can’t ventilate (CICV)], possible emergency tracheostomy and cardiovascular and cervical spine issues. Because of the high anaesthetic risk, the benefits of a procedure in patients with MPS shoul

Drama and discounting in the relational dynamics of corporate social responsibility

Employing theoretical resources from Transactional Analysis (TA) and drawing from interviews with managers dealing with social or environmental issues in their role, we explain how CSR activity provides a context for dramas in which actors may ignore, or discount aspects of self, others, and the contexts of their work as they maintain and reproduce the roles of Rescuers, Persecutors and Victims. In doing so, we add to knowledge about CSR by providing an explanation for how the contradictions of CSR are avoided in practice even when actors may be aware of them. Specifically, we theorise how CSR work can produce dramatic stories where adversity is apparently overcome, whilst little is actually achieved at the social level. We also add to the range of psychoanalytic tools used to account for organisational behaviours, emphasising how TA can explain the relational dynamics of CSR

Hydroxylation of a hederagenin derived saponin by a xylareaceous fungus found in fruits of Sapindus saponaria

During our screening of tropical plants for endophyte microorganisms, a Xylareaceous fungus was found living on the internal part of Sapindus saponaria fruits. The fruits of S. saponaria accumulate great amounts of triterpenoidal and sesquiterpenoidal saponins. The saponin 3-O-(&#946;-D-xylopyranosyl)-(1&#8594;3)-&#945;-L-rhamnopyranosyl-(1&#8594;2)-&#945;-L-arabinopyranosyl-hederagenin was isolated using chromatographic methods, after alkaline hydrolysis of the crude extract obtained from S. saponaria fruits and added to the culture medium used to grows the fungus. A new saponin was isolated from this experiment by preparative scale HPLC and characterized as a 22&#945;-hydroxy derivative. The structure of this hydroxylated saponin was elucidated based on interpretation of MS/MS data and NMR spectra