Initial results from the New Horizons exploration of 2014 MU69, a small Kuiper Belt object.

The Kuiper Belt is a distant region of the outer Solar System. On 1 January 2019, the New Horizons spacecraft flew close to (486958) 2014 MU69, a cold classical Kuiper Belt object approximately 30 kilometers in diameter. Such objects have never been substantially heated by the Sun and are therefore well preserved since their formation. We describe initial results from these encounter observations. MU69 is a bilobed contact binary with a flattened shape, discrete geological units, and noticeable albedo heterogeneity. However, there is little surface color or compositional heterogeneity. No evidence for satellites, rings or other dust structures, a gas coma, or solar wind interactions was detected. MU69's origin appears consistent with pebble cloud collapse followed by a low-velocity merger of its two lobes.

Incidental finding of large pneumothorax on Cardiac MR scan.

BACKGROUND: We believe this is the first case report of a pneumothorax being identified using cardiac magnetic resonance imaging. This case also illustrates the haemodynamic effect a large pneumothorax can have on right ventricular filling in diastole. CASE PRESENTATION: A 26-year-old attended for an interval follow up Cardiac Magnetic Resonance (CMR) of his thoracic aorta after a thoracic co-arctation repair aged 3. He was found to have an incidental large pneumothorax by the reporting cardiology fellow which was confirmed by the on-call radiologist. The pneumothorax was most notable for its compression of the right ventricle in diastole. Although the patient had worrying features on CMR imaging, he remained clinically stable and a conservative approach to management saw the pneumothorax resolve after a 3 week period. CONCLUSIONS: Pneumothoraces are important, potentially life threatening conditions. Although very rarely identified on MR imaging, radiographers and reporting doctors should be aware of their key features. This case serves to identify not only the abnormal lung parenchymal features but also the striking compressional effect of the pneumothorax on the right ventricle in diastole. Indeed we believe this is the first case report of a pneumothorax identified on CMR imaging.

Potentially toxic element release by fenton oxidation of sewage sludge.

The presence, in sewage sludge, of excess levels of the potentially toxic elements (PTE) copper, zinc, chromium, cadmium, nickel, lead and mercury, could impact on our ability to recycle these residues in the future. Far stricter limits on the levels of PTEs are likely in proposed legislation. A method involving the dosing of Fenton's reagent, a mixture of ferrous iron and hydrogen peroxide, under acidic conditions was evaluated for its potential to reduce metal levels. The [Fe]:[H2O2] (w/w) ratio was found to give a good indication of the percentage copper and zinc elution obtainable. Sites with no iron dosing as part of wastewater treatment required extra iron to be added in order to initiate the Fenton's reaction. A significant reduction, in excess of 70%, of the copper and zinc was eluted from both raw primary and activated sludge solid fractions. Cadmium and nickel could be reduced to below detection limits but elution of mercury, lead and chromium was less than 40%. The iron catalyst concentration was found to be a crucial parameter. This process has the potential to reduce the heavy metal content of the sludge and allow the recycling of sludge to continue in a sustainable manner.

Place(ment) matters: students' clinical experiences and their preferences for first employers.

BACKGROUND: Although a significant volume of nursing research has focused on students' experiences of clinical placements, to date, none has considered these experiences in the context of workforce recruitment and specifically how they may impact upon preferences for working for health care providers. METHODS: In this context, the research used a place-sensitive geographical perspective and a combined questionnaire (n = 650), interview (n = 30) and focus group (n = 7) method to collect data on the complex range of clinical experiences which together impact upon the perceived attractiveness of different health care settings. FINDINGS: The data identified a range of experiential factors associated with mentorship, ward management, learning opportunities and racism. An important finding was that although students' experiences are obtained at the micro ward level, even if they may not necessarily reflect what happens throughout the hospital, they potentially impact, both positively and negatively, upon their broader perceptions of the hospital and the likelihood of seeking work there. IMPLICATIONS: The study highlighted a variety of issues that should be addressed by both higher education institutions and hospitals so that they may be able to provide a more consistent and positive experience for students. In the longer term, this may pay dividends through increased recruitment of new graduates.

Perceptions of nursing: confirmation, change and the student experience.

Research has identified a number of negative societal perceptions of nursing related to gendered stereotyping, subordination to doctors, low academic standards, limited career opportunities and poor pay and conditions, and importantly how these perceptions may affect levels of recruitment into nursing. Focusing specifically on nurses, research has also considered the extent to which these societal perceptions are realities in their workplaces, and the direct experiences that contribute to attrition from both nursing courses and jobs. However, to date, few research has actually bridged the above approaches and considered the perceptions that nursing students hold as they first enter their education and how these change, or are confirmed, as a result of their experiences. In this context, the current study uses a combined questionnaire (n = 650), interview (n = 30) and focus group (n = 7) methodology to investigate the experiences of students based at two British Universities. The findings suggest that many students were surprised, yet not overwhelmed, by the high academic standards required of them and came to recognize and value the tremendous knowledge, skills set and responsibilities of nurses as they acquired them. However, their experiences reinforced both society's and their own image of an underpaid, overworked profession that lacks respect and has low morale. The findings support media initiatives that emphasize nurses' skills in order to influence public opinion. They also support a range of subtle changes in nurse education at the institutional level to make student life easier. Nevertheless, it is acknowledged that these may have a limited impact unless pay and conditions are adequately addressed at the national level.

Immediate implantation into the posterior maxilla after antroplasty: the Cranin-Russell Operation.

Heretofore, the absence of adequate alveolar bone (4 mm or less) beneath the maxillary sinus has prevented placement of endosteal root-form implants at the same time as antroplasty. A technique has been devised which permits implantation to occur upon the occasion of sinus floor elevation. This has been made possible by the use of titanium fracture miniplates, which serve as transitional fixation devices until mineralization of the graft material creates implant osseointegration.

An early event associated with liver carcinogenesis involving loss of a polypeptide that binds carcinogen.

This report describes an early and direct action of oncogenic agents and its apparent consequences. Chemical carcinogen has been found to interact principally with a specific polypeptide in livers of normal rats. Short-term ingestion of carcinogen causes marked reductions in the concentrations of both the carcinogen:polypeptide complex and the polypeptide itself. This action and its consequences are unique in several ways. (a) Chemical carcinogen is directly involved in the event. (b) Three kinds of liver carcinogens act in this way: the aromatic amide, N-2-fluorenylacetamide (2-acetylaminofluorene); the aminoazo dye, 3'-methyl-4-dimethylaminoazobenzene; and the amino acid analog, ethionine. (c) The interaction of chemical carcinogen with a specific polypeptide is involved. (d) Both the carcinogen:polypeptide complex and the polypeptide itself undergo marked reductions in concentration during hepatocarcinogenesis by the three types of carcinogens. (e) The consequences of the interaction are sensitive indicators unusually early during liver carcinogenesis. (f) The target polypeptide has a molecular weight of 14,700, similar to those of known polypeptide growth regulators.

Functional acetylcholine receptor--electroplax membrane microsacs (vesicles): purification and characterization.

Kinetic analysis of the flux of sodium ions in a heterogeneous population of acetylcholine receptor-rich microsacs (vesicles) formed by membrane fragments of electroplax indicated that functional microsacs, which on average comprise only 15% of the preparation, can be filled with 190 mM sodium chloride while nonfunctional microsacs are filled by 190 mM cesium chloride. The functional microsacs have then been successfully separated from nonfunctional microsacs on the basis of their density differences with a continuous sucrose-190 mM cesium chloride density gradient. In the presence of acetylcholine analogs all the internal sodium ions in these microsacs rapidly exchange with external ions. The efflux of sodium ions follows a single exponential decay. The isolation of functional microsacs opens up at least two new avenues of investigation of the molecular mechanism of receptor-mediated processes. The first deals with the efficiency of the process, and the second with the characterization of membrane components important in this process. The conclusions reached so far are: (i) The efficiency of the receptor-mediated process that allows inorganic ions to equilibrate across the membranes of the microsacs can adequately account for electrophysiological results obtained with muscle and nerve cells. (ii) In the receptor-rich heterogeneous population of microsacs the concentration of receptor sites in functional and nonfunctional microsacs is about the same and is therefore not the only factor determining functionality. Significant differences between functional and nonfunctional microsacs have been found so far in the concentrations of acetylcholinesterase and Na+-K+ ATPase.

Acetylcholine-receptor-mediated ion flux in electroplax membrane preparations.

The kinetics of acetylcholine-receptor-mediated sodium efflux from electroplax microsacs of electrophorus electricus has been analyzed. This led to the discovery that only a small fraction of the observed efflux is affected by chemical effectors such as carbamylcholine. Experimental conditions were chosen so that the receptor-mediated flux could be analyzed without the measurements' being obscured by efflux from the nonexcitable microsacs. Near equilibrium the efflux follows a single exponential decay. The apparent first order rate constant for sodium-22 efflux was determined as a function of effector concentration and is considerably higher than previously estimated. The process does not show cooperativity under the experimental conditions, in agreement with the binding isotherms of effectors and the same membrane preparation. The presence of potassium ions inhibits the receptor-mediated sodium flux. It is suggested that interaction of inorganic ions with the receptor may play an important role in the cooperative effects observed in electrophysiological experiments.