Investigating the sequence variation in the influenza A matrix genes during the 2017-2018 and 2018-2019 seasons in samples from a local population in London.

Recent publications have highlighted the emergence of mutations in the M1 gene of both influenza A H1N1pdm09 and H3N2 subtypes affecting the performance of commercial RT-PCR assays. Respiratory samples from the 2018/2019 season positive by our in-house RT-PCR for influenza A were analysed for the prevalence and impact of any M1 gene mutations. Sequence information was used to re-design primers for our routine assay and their performance assessed. Forty-five samples, consisting of 11 H1N1pdm09 and 34 H3N2 subtypes, together with the NIBSC H1N1 control were sequenced. All samples displayed the core mutations for H1N1 M1(C154T; G174A and G238A) and for H3N2 M1(C153T; C163T and G189T); three of the H1N1pdm09 viruses also showed a small number of point mutations. None of the mutations appeared to affect either the sensitivity or efficiency of the RT-PCR when compared to the re-designed primers. Although the mutations we found agreed with those in the publications cited we did not encounter any problems with our routine diagnostic assay and no improvements were found when the primers were modified to suit those mutations. However, it is likely that the influenza A virus M1 gene will accumulate further mutations that could impact RT-PCR assays and, therefore, it would be prudent to implement routine sequencing of samples during the influenza seasons to ensure no loss in assay performance.

A review of bubble break-up.

The coalescence and break-up of bubbles are important steps in many industrial processes. To date, most of the literature has been focussed on the coalescence process which has been studied using high speed cinematographic techniques. However, bubble break-up is equally important and requires further research. This review essentially details the break-up process and initially summarizes the different types of bubble deformation processes which lead to break-up. Break-up is considered in high and low turbulent (pseudo-static) conditions and the effect of fluctuations and shear forces on the break-up is reviewed. Different mechanisms of break-up are discussed including shearing-off, coalescence induced pitching and impact pinching following air entrapment. Also, the influence of bubble size, interfacial stability, and surfactant on break-up are reviewed and a summary of recent experimental techniques presented. Finally, the break-up process which occurs in micro-fluidics is summarized.

Using Sound To Study the Effect of Frothers on the Breakaway of Air Bubbles at an Underwater Capillary.

Frothers, a class of surfactants, are widely employed in froth flotation to aid the generation of small bubbles. Their action is commonly explained by their ability to hinder coalescence. There are occasional references suggesting that the frother may also play a role in the initial breakup of the injected air mass. This work investigates the possible effect of the frother on breakup by monitoring air bubbles produced quasi-statically at an underwater capillary. Under this condition, breakup is isolated from coalescence and an impact of frothers on the detached bubble can be ascribed to an impact on breakup. The breakaway process was monitored by an acoustic technique along with high-speed cinematography. The results showed that the presence of frothers did influence the breakaway process and that the acoustic technique was able to detect the impact. It was demonstrated that the acoustic frequency and acoustic damping ratio depend upon the frother type and concentration and that they are associated with a liquid jet, which initially excites the bubble and then decays to form a surface wave. The addition of the frother did not influence the formation of the jet but did increase its decay rate, hence, dampening the surface wave. It is postulated that the action of the frother is related to an effect on the magnitude of surface tension gradients.

Challenges of chronic pain management: public health consequences and considered responses.

This article reviews the public health consequences of current approaches to chronic pain management, particularly those related to prescription of opioid analgesics and other controlled medications. This article also reviews factors contributing to these negative trends and discusses potential strategies for reversing them.

Two-year Experience with Buprenorphine-naloxone (Suboxone) for Maintenance Treatment of Opioid Dependence Within a Private Practice Setting.

Office-based buprenorphine-naloxone (Suboxone) treatment in the United States has significantly improved access to safe and effective opioid-dependence therapy. Little data from physicians' experiences prescribing Suboxone in private offices have been available. This retrospective chart review describes a family practitioner's first 2 years of clinical experience prescribing Suboxone for opioid dependence to 71 patients in a private office. After directly observed rapid office dose induction, Suboxone prescriptions were given monthly after evidence of continued stability. Urine was screened regularly and patients were referred for counseling and other ancillary services. Patients averaged 32 years old, 4.3 years of opioid dependence, and were primarily white (93%) and employed (70%). Fifty-two percent used heroin primarily (most by injection), and 70% had no agonist substitution therapy history. Almost half (47%) paid for their own treatment. Compliance during dose induction was excellent. Suboxone maintenance doses averaged 10 (range, 2-24) mg per day. More than 80% of urine samples were opioid-negative after Suboxone treatment began, although urinalysis did not always include a test for oxycodone. Seventy-five percent had successful outcomes by remaining in Suboxone treatment (43%), tapering successfully (21%), transferring to methadone maintenance (7%), or inpatient treatment (4%). Fifty-eight percent reported receiving counseling. Almost all (85%) paid their fees on time. There were no safety, medication abuse, or diversion issues detected. Overall, office-based Suboxone therapy was easily implemented and the physician considered the experience excellent. Suboxone maintenance was associated with good treatment retention and significantly reduced opioid use, and it is helping to reach patients, including injection drug users, without histories of agonist substitution therapy.

Comparative real-time characterization of frother bubble thin films.

Methylisobutyl carbinol (MIBC) and methoxy polypropylene glycol (Dowfroth 250) bubble thin films were characterized by composition and thickness determinations, using FT-IR spectroscopy and UV-visible spectrophotometry, respectively. The infrared investigation indicates that the role of frother molecules in creating bubble thin films is based on their effectiveness in inducing H-bonding reorganization of the surrounding free water molecules into a coherent network. From UV-visible interference patterns, it is found that MIBC forms films with a measured critical end thickness of less than 160 nm, compared to 612+/-30 nm for Dowfroth 250. The observed values of the free water layer thickness are comparable at 5.65+/-0.28 microm for MIBC and 6.75+/-0.34 microm for Dowfroth 250. A higher stability of an MIBC bubble over a Dowfroth 250 bubble is related to the different polarization and orientation of the molecules sustaining the boundary surface water network. The findings are used to explain the different action and associated froth characteristics of the two common industrial frothing agents.

Charge contrast imaging of gibbsite using the variable pressure SEM.

The variable pressure scanning electron microscope (VP-SEM) allows imaging of insulators without the need for a conductive coating, due to charge neutralization at the surface from recombination of positive ions and surface electrons. Varying certain parameters such as pressure, bias, and working distance creates incomplete neutralization, and localized charging develops called charge contrast. Although the exact mechanism creating charge contrast imaging (CCI) is unknown, it is agreed that it is related to an optimum charge compensation. The behavior of the CCI is still vague, which presents a problem for determining the mechanisms. This article provides user-friendly methods of finding the optimum levels of charge contrast in the VP-SEM. We show that the CCI is obtained at optimum operating conditions where the specimen current is between 2.5 nA and 3.5 nA. The specimen current is a function of secondary electrons (SE) emission and ionization potential, producing an ion flux. Therefore an optimum specimen current represents the balanced conditions of SE emission and ion flux. Controlling the pressure, working distance, bias, scan rate, and beam current allows the microscopist to set the specimen current at this optimum level for charge contrast imaging. All the work was performed on gibbsite using the S3000N VP-SEM from Hitachi.

Possibility of charge contrast imaging of polymeric materials.

Preliminary results illustrate the possibility of charge contrast imaging (CCI) of polymeric materials. Possible CCI images of low-density polyethylene and polyvinyl chloride reveal details that may aid in the characterization of the microstructure of polymeric materials. These pictures were obtained with a Hitachi S-3000N variable pressure scanning electron microscope with the environmental secondary electron detector (ESED).