Static and dynamic magnetic properties of polycrystalline hexaferrites of the Ba2Ni2-xCuxFe12O22 system

The paper presents the results of a study of the phase composition and the main static magnetic characteristics: saturation magnetization, residual magnetization and coercive force of polycrystalline ferroxplana type hexaferrites of the Ba2Ni2-xCuxFe12O22 (0 < x < 2.0) system. These materials have high magnetic permeability and are promising for use as substrates for magnetic antennas and radar absorbing materials. It is shown that thermograms of the initial permeability can be used to quickly assess the presence of impurity magnetic phases in complex oxide ferrimagnets. The permeability and permittivity spectra of textured and non-textured composite samples with the powder of the Ba2NiCuFe12O22 hexaferrite are measured in the microwave frequency range. The radar absorbing properties of the obtained composites are analyzed. It is shown that magnetic texturing leads to an increase in the operating frequency band of an absorber with RL < -10 dB from 6.1 GHz to 8.2 GHz and a deepening of the loss minimum from -21 dB to -27 dB

Knowledge and attitudes of Australian general practitioners towards medicinal cannabis: a cross-sectional survey.

OBJECTIVES: To examine the knowledge and attitudes of Australian general practitioners (GP) towards medicinal cannabis, including patient demand, GP perceptions of therapeutic effects and potential harms, perceived knowledge and willingness to prescribe. DESIGN, SETTING AND PARTICIPANTS: A cross-sectional survey completed by 640 GPs (response rate=37%) attending multiple-topic educational seminars in five major Australian cities between August and November 2017. MAIN OUTCOME MEASURES: Number of patients enquiring about medicinal cannabis, perceived knowledge of GPs, conditions where GPs perceived it to be beneficial, willingness to prescribe, preferred models of access, perceived adverse effects and safety relative to other prescription drugs. RESULTS: The majority of GPs (61.5%) reported one or more patient enquiries about medicinal cannabis in the last three months. Most felt that their own knowledge was inadequate and only 28.8% felt comfortable discussing medicinal cannabis with patients. Over half (56.5%) supported availability on prescription, with the preferred access model involving trained GPs prescribing independently of specialists. Support for use of medicinal cannabis was condition-specific, with strong support for use in cancer pain, palliative care and epilepsy, and much lower support for use in depression and anxiety. CONCLUSIONS: The majority of GPs are supportive or neutral with regards to medicinal cannabis use. Our results highlight the need for improved training of GPs around medicinal cannabis, and the discrepancy between GP-preferred models of access and the current specialist-led models

Chronic methamphetamine self-administration dysregulates oxytocin plasma levels and oxytocin receptor fibre density in the nucleus accumbens core and subthalamic nucleus of the rat

The neuropeptide oxytocin attenuates reward and abuse for the psychostimulant methamphetamine (METH). Recent findings have implicated the nucleus accumbens (NAc) core and subthalamic nucleus (STh) in oxytocin modulation of acute METH reward and relapse to METH-seeking behaviour. Surprisingly, the oxytocin receptor (OTR) is only modestly involved in both regions in oxytocin attenuation of METH-primed reinstatement. Coupled with the limited investigation of the role of the OTR in psychostimulant-induced behaviours, we primarily investigated whether there are cellular changes to the OTR in the NAc core and STh, as well as changes to oxytocin plasma levels, after chronic METH i.v. self-administration (IVSA) and after extinction of drug-taking. An additional aim was to examine whether changes to central corticotrophin-releasing factor (CRF) and plasma corticosterone levels were also apparent because of the interaction of oxytocin with stress-regulatory mechanisms. Male Sprague-Dawley rats were trained to lever press for i.v. METH (0.1 mg/kg/infusion) under a fixed-ratio 1 schedule or received yoked saline infusions during 2-h sessions for 20 days. An additional cohort of rats underwent behavioural extinction for 15 days after METH IVSA. Subsequent to the last day of IVSA or extinction, blood plasma was collected for enzyme immunoassay, and immunofluorescence was conducted on NAc core and STh coronal sections. Rats that self-administered METH had higher oxytocin plasma levels, and decreased OTR-immunoreactive (-IR) fibres in the NAc core than yoked controls. In animals that self-administered METH and underwent extinction, oxytocin plasma levels remained elevated, OTR-IR fibre density increased in the STh, and a trend towards normalisation of OTR-IR fibre density was evident in the NAc core. CRF-IR fibre density in both brain regions and corticosterone plasma levels did not change across treatment groups. These findings demonstrate that oxytocin systems, both centrally within the NAc core and STh, as well as peripherally through plasma measures, are dysregulated after METH abuse.13 page(s