Nanoscale intermittent contact-scanning electrochemical microscopy

A major theme in scanning electrochemical microscopy (SECM) is a methodology for nanoscale imaging with distance control and positional feedback of the tip. We report the expansion of intermittent contact (IC)-SECM to the nanoscale, using disk-type Pt nanoelectrodes prepared using the laser-puller sealing method. The Pt was exposed using a focused ion beam milling procedure to cut the end of the electrode to a well-defined glass sheath radius, which could also be used to reshape the tips to reduce the size of the glass sheath. This produced nanoelectrodes that were slightly recessed, which was optimal for IC-SECM on the nanoscale, as it served to protect the active part of the tip. A combination of finite element method simulations, steady-state voltammetry and scanning electron microscopy for the measurement of critical dimensions, was used to estimate Pt recession depth. With this knowledge, the tip-substrate alignment could be further estimated by tip approach curve measurements. IC-SECM has been implemented by using a piezo-bender actuator for the detection of damping of the oscillation amplitude of the tip, when IC occurs, which was used as a tip-position feedback mechanism. The piezo-bender actuator improves significantly on the performance of our previous setup for IC-SECM, as the force acting on the sample due to the tip is greatly reduced, allowing studies with more delicate tips. The capability of IC-SECM is illustrated with studies of a model electrode (metal/glass) substrate

Psychosocial predictors of hope two years after diagnosis of colorectal cancer: Implications for nurse-led hope programmes

© 2019 John Wiley & Sons Ltd Objective: To prospectively explore predictors of hope in people with colorectal cancer at 24 months post-diagnosis. Methods: The present study is a secondary analysis of two waves within a longitudinal survey of patients newly diagnosed with colorectal cancer in Queensland, Australia. Baseline predictors (sociodemographic, disease, lifestyle characteristics, cancer threat appraisal and quality of life domains) were measured via mailed surveys and telephone interviews at 6 months post-diagnosis. Hope was measured via mailed surveys at 24 months post-diagnosis. Results: At 24 months post-diagnosis, 1,265 participants completed the hope measure. Hope was predicted by higher education, physical activity, cancer threat appraisal and each quality of life domain (i.e., physical, social, emotional and functional well-being; and colorectal cancer-specific concerns), which explained 23.63% of the total variance in hope, F(14, 1,081) = 23.89, p < 0.001. Conclusion: At 24 months post-diagnosis, hope was associated with greater functional, social and emotional well-being, and less threatened cancer appraisals. As hope programmes continue to be developed, designers should include activities that increase well-being and reduce cancer threat appraisal for people with colorectal cancer

Complete Genome Sequence of Stenotrophomonas maltophilia Strain CF13, Recovered from Sputum from an Australian Cystic Fibrosis Patient.

Stenotrophomonas maltophilia isolate CF13 is a multidrug-resistant isolate that was recovered in Sydney, Australia, in 2011, from a sputum sample from an individual with cystic fibrosis. The genome sequence of CF13 was completed using long- and short-read technologies

The validity of the Distress Thermometer in female partners of men with prostate cancer

© 2018 John Wiley & Sons Ltd Female partners of prostate cancer (PCa) survivors experience heightened psychological distress that may be greater than that expressed by PCa patients. However, optimal approaches to detect distressed, or at risk of distress, partners are unclear. This study applied receiver operating characteristics analysis to evaluate diagnostic accuracy, sensitivity and specificity of the Distress Thermometer (DT) compared to widely used measures of general (Hospital Anxiety and Depression Scale) and cancer-specific (Impact of Events Scale-Revised) distress. Participants were partners of men with localised PCa (recruited around diagnosis) about to undergo or had received surgical treatment (N = 189), and partners of men diagnosed with PCa who were 2–4 years post-treatment (N = 460). In both studies, diagnostic utility of the DT overall was not optimal. Although area under the curve scores were acceptable (ranges: 0.71–0.92 and 0.83–0.94 for general and cancer-specific distress, respectively), sensitivity, specificity and optimal DT cut-offs for partner distress varied for general (range: ≥2 to ≥5) and cancer-specific (range: ≥3 to ≥5) distress both across time and between cohorts. Thus, it is difficult to draw firm conclusions about the diagnostic capabilities of the DT for partners or recommend its use in this population. More comprehensive screening measures may be needed to detect partners needing psychological intervention

Transmission dynamics of Tasmanian devil facial tumor disease may lead to disease-induced extinction

Most pathogens threatening to cause extinction of a host species are maintained on one or more reservoir hosts, in addition to the species that is threatened by disease. Further, most conventional host–pathogen theory assumes that transmission is related to host density, and therefore a pathogen should become extinct before its sole host. Tasmanian devil facial tumor disease is a recently emerged infectious cancer that has led to massive population declines and grave concerns for the future persistence of this largest surviving marsupial carnivore. Here we report the results of mark–recapture studies at six sites and use these data to estimate epidemiological parameters critical to both accurately assessing the risk of extinction from this disease and effectively managing this disease threat. Three sites were monitored from before or close to the time of disease arrival, and at three others disease was well established when trapping began, in one site for at least 10 years. We found no evidence for sex-specific differences in disease prevalence and little evidence of consistent seasonal variation in the force of infection. At all sites, the disease was maintained at high levels of prevalence (>50% in 2–3-year-old animals), despite causing major population declines. We also provide the first estimates of the basic reproductive rate R0 for this disease. Using a simple age-structured deterministic model, we show that our results are not consistent with transmission being proportional to the density of infected hosts but are consistent with frequency-dependent transmission. This conclusion is further supported by the observation that local disease prevalence in 2–3-year-olds still exceeds 50% at a site where population density has been reduced by up to 90% in the past 12 years. These findings lend considerable weight to concerns that this host-specific pathogen will cause the extinction of the Tasmanian devil. Our study highlights the importance of rapidly implementing monitoring programs to determine how transmission depends on host density and emphasizes the need for ongoing management strategies involving a disease-free “insurance population,” along with ongoing field monitoring programs to confirm whether local population extinction occur

Determining the Effects of Past Negative Experiences Involving Patient Care

As the cost of healthcare continues to raise, the need to address nurse attrition, which is a contributing factor, also rises. While there are various factors that influence nurses’ decision to leave or stay, job satisfaction and ethical climate are significant variables. This study examined the effects of negative previous work experiences on job satisfaction and ethical climate. The results showed previous work experiences moderated both job satisfaction and ethical climate. In addition, ethical climate mediated the effects of previous experiences on job satisfaction. The implications include identifying nurses who may have had negative experiences prior to their current employment and providing them with ongoing support

The Relationship of Moral Distress, Ethical Environment and Nurse Job Satisfaction

Nurses are fundamental to the delivery of quality, safe and competent health care in multilevel complex systems. Faced with challenging, dynamic, and evolving patient care and workforce issues, nurses must create ethical environments, which foster a respectful climate in which decisions are made and supported. The current study examined the relationship between ethical climate, frequency of moral distress, intensity of moral distress, and overall job satisfaction among registered nurses at two hospitals located in the Southeastern United States as measured by the Moral Distress Scale and the Hospital Ethical Climate Survey. The results of the correlational study suggest a weak relationship between ethical climate and moral distress, but a moderate relationship exists between ethical climate and job satisfaction. Findings from this study highlight the importance of creating an ethical environment to improve job satisfaction which can ultimately result in improved patient care

The HSP90 inhibitor ganetespib: a potential effective agent for Acute Myeloid Leukemia in combination with cytarabine

HSP90 is a multi-client chaperone involved in regulating a large array of cellular processes and is commonly overexpressed in many different cancer types including hematological malignancies. Inhibition of HSP90 holds promise for targeting multiple molecular abnormalities and is therefore an attractive target for heterogeneous malignancies such as Acute Myeloid Leukemia (AML). Ganetespib is a highly potent second generation HSP90 inhibitor which we show is significantly more effective against primary AML blasts at nanomolar concentrations when compared with cytarabine (p < 0.001). Dose dependant cytotoxicity was observed with an apoptotic response coordinate with the loss of pro-survival signaling through the client protein AKT. Combination treatment of primary blasts with ganetespib and cytarabine showed good synergistic interaction (combination index (CI): 0.47) across a range of drug effects with associated reduction in HSP70 feedback and AKT signaling levels. In summary, we show ganetespib to have high activity in primary AMLs as a monotherapy and a synergistic relationship with cytarabine when combined. The combination of cytotoxic cell death, suppression of cytoprotective/drug resistance mechanisms such as AKT and reduced clinical toxicity compared to other HSP90 inhibitors provide strong rationale for the clinical assessment of ganetespib in AML

Hopping intermittent contact-scanning electrochemical microscopy (HIC-SECM) as a new local dissolution kinetic probe : application to salicylic acid dissolution in aqueous solution

Dissolution kinetics of the (110) face of salicylic acid in aqueous solution is determined by hopping intermittent contact-scanning electrochemical microscopy (HIC-SECM) using a 2.5 μm diameter platinum ultramicroelectrode (UME). The method operates by translating the probe UME towards the surface at a series of positions across the crystal and inducing dissolution via the reduction of protons to hydrogen, which titrates the weak acid and promotes the dissolution reaction, but only when the UME is close to the crystal. Most importantly, as dissolution is only briefly and transiently induced at each location, the initial dissolution kinetics of an as-grown single crystal surface can be measured, rather than a surface which has undergone significant dissolution (pitting), as in other techniques. Mass transport and kinetics in the system are modelled using finite element method simulations which allows dissolution rate constants to be evaluated. It is found that the kinetics of an ‘as-grown’ crystal are much slower than for a surface that has undergone partial bulk dissolution (mimicking conventional techniques), which can be attributed to a dramatic change in surface morphology as identified by atomic force microscopy (AFM). The ‘as-grown’ (110) surface presents extended terrace structures to the solution which evidently dissolve slowly, whereas a partially dissolved surface has extensive etch features and step sites which greatly enhance dissolution kinetics. This means that crystals such as salicylic acid will show time-dependent dissolution kinetics (fluxes) that are strongly dependent on crystal history, and this needs to be taken into account to fully understand dissolution

Pseudomonas aeruginosa is capable of natural transformation in biofilms

Natural transformation is a mechanism that enables competent bacteria to acquire naked, exogenous DNA from the environment. It is a key process that facilitates the dissemination of antibiotic resistance and virulence determinants throughout bacterial populations. Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen that produces large quantities of extracellular DNA (eDNA) that is required for biofilm formation. P. aeruginosa has a remarkable level of genome plasticity and diversity that suggests a high degree of horizontal gene transfer and recombination but is thought to be incapable of natural transformation. Here we show that P. aeruginosa possesses homologues of all proteins known to be involved in natural transformation in other bacterial species. We found that P. aeruginosa in biofilms is competent for natural transformation of both genomic and plasmid DNA. Furthermore, we demonstrate that type-IV pili (T4P) facilitate but are not absolutely essential for natural transformation in P. aeruginosa