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1.
BMC Med Educ ; 23(1): 415, 2023 Jun 06.
Article En | MEDLINE | ID: mdl-37280631

BACKGROUND: Medical educational courses can be successful from an immediate feedback perspective but not lead to new behaviour or organisational changes in the workplace. The aim of this study was to assess the self-perceived impact of the European Trauma Course (ETC) on Reanima trainees' behaviour and organisational change. METHODS: A 40-item questionnaire based on Holton's evaluation model was used to evaluate the candidate's perceptions. The results were analysed with descriptive and inferential statistical analysis using nonparametric tests with α = 0.05. RESULTS: Out of 295 participants, 126 responded to the survey. Of these, 94% affirmed that the ETC modified their approach to trauma patients, and 71.4% described a change in their behaviour. Postcourse responders changed their behaviour in their initial approach to trauma care in the nontechnical skills of communication, prioritisation and teamwork. Being an ETC instructor strongly influenced the acquisition of new material, and this group was able to implement changes in attitudes. Individuals with no previous trauma course experience identified lack of self-efficacy as a significant obstacle to introducing new work-based learning. In contrast, responders with ATLS training noted a lack of ETC colleagues as the main impediment for moving from conceptualisation to experimentation in the workplace. CONCLUSIONS: Participation in the ETC led to behavioural changes in the workplace. However, the ability to influence others and bring about wider organisational changes was more difficult to achieve. Major factors were the status of the person, their experience and self-efficacy. National organisational impact was obtained, which went far beyond our aspirations in acknowledging change in individual daily practice. Future research studies will include the effect of implementing the ETC methodology on the outcome of trauma patients.


Education, Medical , Learning , Humans , Portugal , Attitude , Organizational Innovation
2.
Surg Endosc ; 37(1): 556-563, 2023 01.
Article En | MEDLINE | ID: mdl-36006523

BACKGROUND: Where the critical view of safety cannot be established during cholecystectomy, certain salvage techniques are indicated to reduce the likelihood of bile duct injury. The present study describes a salvage technique termed the "laparoscopic lumen-guided cholecystectomy" (LLC) and reports its peri-operative outcomes. METHOD: A summary of the technique is as follows: (1) Hartmann's pouch is incised and stones are evacuated; (2) the cystic anatomy is inspected from the inside of the gallbladder; (3) the lumen is used to guide retrograde dissection towards the cystic pedicle; (4) cystic duct control is achieved if deemed safe. LLC cases performed between June 2020 and January 2022 in a single health board were included. The operative details and peri-operative outcomes of the technique are reported and compared to cases of similar difficulty where the LLC was not attempted. RESULTS: LLC was performed in 4.6% (27/587) of cases. In all 27 cases, LLC was performed for a "frozen" cholecystohepatic triangle. Hartmann's pouch was completely excised in all cases (27/27) and cystic duct control was achieved in 85.2% of cases (23/27). No cases of bile leak or ductal injury were reported. Rates of bile leak, post-operative complications and ERCP were lower following LLC compared to the group where LLC was not attempted (p < 0.01). CONCLUSION: LLC is a safe salvage technique and should be considered in cases where the critical view of safety cannot be established. The technique achieves cystic duct control in the majority of cases and favourable outcomes in the face of a difficult cholecystectomy.


Cholecystectomy, Laparoscopic , Gallstones , Humans , Cholecystectomy, Laparoscopic/methods , Cystic Duct/surgery , Cholecystectomy , Gallstones/surgery
3.
Proc Natl Acad Sci U S A ; 119(1)2022 Jan 04.
Article En | MEDLINE | ID: mdl-34969863

Light elements in Earth's core play a key role in driving convection and influencing geodynamics, both of which are crucial to the geodynamo. However, the thermal transport properties of iron alloys at high-pressure and -temperature conditions remain uncertain. Here we investigate the transport properties of solid hexagonal close-packed and liquid Fe-Si alloys with 4.3 and 9.0 wt % Si at high pressure and temperature using laser-heated diamond anvil cell experiments and first-principles molecular dynamics and dynamical mean field theory calculations. In contrast to the case of Fe, Si impurity scattering gradually dominates the total scattering in Fe-Si alloys with increasing Si concentration, leading to temperature independence of the resistivity and less electron-electron contribution to the conductivity in Fe-9Si. Our results show a thermal conductivity of ∼100 to 110 W⋅m-1⋅K-1 for liquid Fe-9Si near the topmost outer core. If Earth's core consists of a large amount of silicon (e.g., > 4.3 wt %) with such a high thermal conductivity, a subadiabatic heat flow across the core-mantle boundary is likely, leaving a 400- to 500-km-deep thermally stratified layer below the core-mantle boundary, and challenges proposed thermal convection in Fe-Si liquid outer core.

4.
Neurosci Biobehav Rev ; 131: 597-617, 2021 12.
Article En | MEDLINE | ID: mdl-34571119

The Roman High- (RHA) and Low-(RLA) avoidance rat lines/strains were generated through bidirectional selective breeding for rapid (RHA) vs. extremely poor (RLA) two-way active avoidance acquisition. Compared with RLAs and other rat strains/stocks, RHAs are characterized by increased impulsivity, deficits in social behavior, novelty-induced hyper-locomotion, impaired attentional/cognitive abilities, vulnerability to psychostimulant sensitization and drug addiction. RHA rats also exhibit decreased function of the prefrontal cortex (PFC) and hippocampus, increased functional activity of the mesolimbic dopamine system and a dramatic deficit of central metabotropic glutamate-2 (mGlu2) receptors (due to a stop codon mutation at cysteine 407 in Grm2 -cys407*-), along with increased density of 5-HT2A receptors in the PFC, alterations of several synaptic markers and increased density of pyramidal "thin" (immature) dendrític spines in the PFC. These characteristics suggest an immature brain of RHA rats, and are reminiscent of schizophrenia features like hypofrontality and disruption of the excitation/inhibition cortical balance. RHA rats represent a promising heuristic model of neurodevelopmental schizophrenia-relevant features and comorbidity with drug addiction vulnerability.


Behavior, Addictive , Schizophrenia , Animals , Avoidance Learning/physiology , Heuristics , Models, Genetic , Prefrontal Cortex , Rats , Schizophrenia/genetics
5.
Nat Commun ; 12(1): 876, 2021 Feb 09.
Article En | MEDLINE | ID: mdl-33563984

The essential data for interior and thermal evolution models of the Earth and super-Earths are the density and melting of mantle silicate under extreme conditions. Here, we report an unprecedently high melting temperature of MgSiO3 at 500 GPa by direct shockwave loading of pre-synthesized dense MgSiO3 (bridgmanite) using the Z Pulsed Power Facility. We also present the first high-precision density data of crystalline MgSiO3 to 422 GPa and 7200 K and of silicate melt to 1254 GPa. The experimental density measurements support our density functional theory based molecular dynamics calculations, providing benchmarks for theoretical calculations under extreme conditions. The excellent agreement between experiment and theory provides a reliable reference density profile for super-Earth mantles. Furthermore, the observed upper bound of melting temperature, 9430 K at 500 GPa, provides a critical constraint on the accretion energy required to melt the mantle and the prospect of driving a dynamo in massive rocky planets.

7.
Astrobiology ; 18(2): 133-189, 2018 02.
Article En | MEDLINE | ID: mdl-29431479

Proxima Centauri b provides an unprecedented opportunity to understand the evolution and nature of terrestrial planets orbiting M dwarfs. Although Proxima Cen b orbits within its star's habitable zone, multiple plausible evolutionary paths could have generated different environments that may or may not be habitable. Here, we use 1-D coupled climate-photochemical models to generate self-consistent atmospheres for several evolutionary scenarios, including high-O2, high-CO2, and more Earth-like atmospheres, with both oxic and anoxic compositions. We show that these modeled environments can be habitable or uninhabitable at Proxima Cen b's position in the habitable zone. We use radiative transfer models to generate synthetic spectra and thermal phase curves for these simulated environments, and use instrument models to explore our ability to discriminate between possible planetary states. These results are applicable not only to Proxima Cen b but to other terrestrial planets orbiting M dwarfs. Thermal phase curves may provide the first constraint on the existence of an atmosphere. We find that James Webb Space Telescope (JWST) observations longward of 10 µm could characterize atmospheric heat transport and molecular composition. Detection of ocean glint is unlikely with JWST but may be within the reach of larger-aperture telescopes. Direct imaging spectra may detect O4 absorption, which is diagnostic of massive water loss and O2 retention, rather than a photosynthetic biosphere. Similarly, strong CO2 and CO bands at wavelengths shortward of 2.5 µm would indicate a CO2-dominated atmosphere. If the planet is habitable and volatile-rich, direct imaging will be the best means of detecting habitability. Earth-like planets with microbial biospheres may be identified by the presence of CH4-which has a longer atmospheric lifetime under Proxima Centauri's incident UV-and either photosynthetically produced O2 or a hydrocarbon haze layer. Key Words: Planetary habitability and biosignatures-Planetary atmospheres-Exoplanets-Spectroscopic biosignatures-Planetary science-Proxima Centauri b. Astrobiology 18, 133-189.


Biological Evolution , Exobiology/methods , Extraterrestrial Environment , Models, Biological , Planets , Atmosphere/chemistry , Carbon Dioxide/chemistry , Carbon Monoxide/chemistry , Climate , Evolution, Planetary , Exobiology/instrumentation , Hot Temperature , Oceans and Seas , Radiation Effects , Telescopes , Water/chemistry
8.
Am J Emerg Med ; 35(6): 860-866, 2017 Jun.
Article En | MEDLINE | ID: mdl-28169039

INTRODUCTION: The routine practice of pre-hospital spinal immobilisation (phSI) for patients with suspected spinal injury has existed for decades. However, the controversy surrounding it resulted in the 2013 publication of a Consensus document by the Faculty of Pre-Hospital Care. The question remains as to whether the quality of evidence in the literature is sufficient to support the Consensus guidelines. This critical review aims to determine the validity of current recommendations by balancing the potential benefits and side effects of phSI. METHOD: A review of the literature was carried out by two independent assessors using Medline, PubMed, EMBASE and the Cochrane Library databases. Manual searches of related journals and reference lists were also completed. The selected body of evidence was subsequently appraised using a checklist derived from SIGN and CASP guidelines, as well as Crombie's guide to critical appraisal. RESULTS: No reliable sources were found proving the benefit for patient immobilisation. In contrast there is strong evidence to show that pre-hospital spinal immobilisation is not benign with recognised complications ranging from discomfort to significant physiological compromise. The published literature supports the Consensus guideline recommendations for safely reducing the impact of these side effects without compromising the patient. CONCLUSION: The literature supports the Consensus Guidelines but raises the question as to whether they go far enough as there is strong evidence to suggest phSI is an inherently harmful procedure without having any proven benefit. These results demonstrate an urgent need for further studies to determine its treatment effect.


Emergency Medical Services/standards , Immobilization/adverse effects , Spinal Cord Injuries/therapy , Spinal Injuries/therapy , Humans , Practice Guidelines as Topic , Randomized Controlled Trials as Topic , Spinal Cord Injuries/diagnosis , Spinal Injuries/diagnosis
9.
Emerg Med J ; 34(8): 538-542, 2017 Aug.
Article En | MEDLINE | ID: mdl-27613753

In the past three decades, mass casualty incidents have occurred worldwide at multiple sporting events and other mass gatherings. Organisational safety and healthcare provision can consequently be scrutinised post-event. Within the UK, such incidents in the 1980s provided incentives to improve medical services and subsequent high profile UK-based international sporting events (London Olympics and Paralympics 2012, Glasgow Commonwealth Games 2014, Rugby World Cup 2015) added a further catalyst for developing services. Furthermore in the aftermath of the abandoned France versus Germany association football match at the Stade de France (Paris Terrorist Attacks, November 2015) and the 2016 UK report from HM Coroner on the Hillsborough Inquest, medical cover at sporting events is being further reviewed. Doctors providing spectator cover therefore need to have an awareness of their likely roles at sporting venues. Formal guidance exists in many countries for the provision of such cover but remains generic even though Events Medicine is increasingly recognised as a necessary service. The current evidence base is limited with best practice examples often anecdotally cited by acute care specialists (eg, emergency medicine) who provide cover. This article is therefore intended to present an overview for doctors of the knowledge and skills required to treat ill and injured spectators and enable them to adequately risk-assess venues in cooperation with other health and safety providers, including preparation for a major incident. It also gives guidance on how activity can be adequately assessed and how doctors can have management roles in Events Medicine.


Anniversaries and Special Events , Emergency Medicine/methods , Mass Casualty Incidents/history , Terrorism/history , Emergency Medical Services/organization & administration , Europe , History, 21st Century , Humans , Workforce
10.
Emerg Med J ; 30(10): 858-9, 2013 Oct.
Article En | MEDLINE | ID: mdl-24014689

A shortcut review was carried out to establish whether brachial artery puncture is safe in patients requiring arterial blood sampling. 47 papers were found using the reported searches, of which one presented the best evidence to answer the clinical question. The author, date and country of publication, patient group studied, study type, relevant outcomes, results and study weaknesses of this paper are tabulated. It is concluded that brachial artery puncture is likely to be safe in the non-shocked patient who is not on concurrent anticoagulant therapy.


Blood Specimen Collection/adverse effects , Brachial Artery , Evidence-Based Emergency Medicine , Humans , Punctures/adverse effects
11.
J Laparoendosc Adv Surg Tech A ; 23(2): 100-5, 2013 Feb.
Article En | MEDLINE | ID: mdl-23276250

BACKGROUND: Uncertainty exists surrounding the laparoscopic approach to the repair of giant paraesophageal hiatus hernias (GPHHs), in regard to both long-term outcomes and its role in the emergency presentation. The aim of this study was to assess the outcome of laparoscopic GPHH repair, compared with traditional open surgery, in both the elective and emergency setting. SUBJECTS AND METHODS: Data regarding all patients who underwent GPHH repair between January 1994 and June 2008 were retrieved from the prospectively maintained Lothian Surgical Audit database. Demographic details, surgical approach (open/laparoscopic), conversion to an open procedure, complications, and recurrences were analyzed. RESULTS: Sixty-four patients had GPHH repair. Attempted laparoscopic repair and conversion rates were 52 of 64 (81.2%) and 12 of 52 (23.1%), respectively. Including these conversions, 24 of 64 patients had an open repair. The mean postoperative hospital stay, complications, and mortality were significantly lower among the laparoscopic cohort. Twenty-five of 64 patients had surgery as an emergency admission. Postoperative mortality after emergency surgery was 5 of 25 (20.0%) compared with 3 of 39 (7.6%) among elective patients (P=.146). The recurrence rate after laparoscopic and open repair was 25.0% (10 of 40) and 8.3% (2 of 24), respectively (P=.184). CONCLUSIONS: This study has confirmed that surgical repair of GPHH is associated with a significant morbidity and mortality, in both the elective and emergency setting. Although the laparoscopic approach should be attempted in the first instance, the open approach appears to have a lower recurrence rate.


Elective Surgical Procedures , Emergency Treatment , Hernia, Hiatal/surgery , Herniorrhaphy/methods , Laparoscopy , Adult , Aged , Aged, 80 and over , Female , Hernia, Hiatal/pathology , Humans , Male , Middle Aged
12.
Eur J Emerg Med ; 19(4): 220-5, 2012 Aug.
Article En | MEDLINE | ID: mdl-21915054

OBJECTIVE: Courses in the Advanced Trauma Life Support are a well-accepted concept throughout the world for training in the emergency treatment of polytraumatized patients. Switzerland, a multilingual country with a long tradition of multidisciplinary collaboration in trauma care, introduced its first student courses in 1998. Unlike some countries where the courses are attended only by surgeons, instructors and students in Switzerland include surgeons, anaesthetists and physicians from other specialties. METHODS: Course evaluation assessments and instructor and student demographic data were analysed retrospectively using univariate analyses (Pearson correlation), multivariate analysis of variance, with post-hoc analysis and Bonferroni correction, and stepwise linear regression analysis. RESULTS: Between 1998 and 2003, 922 students attended 58 courses available for evaluation, with 22 338 ratings of different modules. Students rated practical (r=0.076) instruction significantly better than lectures (r=-0.072), gave better rating for women instructors (r=0.026) and for instructors teaching outside their specialty (r=-0.027). Women and participants in French-speaking courses gave better ratings. Ratings by anaesthetists were more critical than by surgeons and students from other specialties. CONCLUSION: The practical format of Advanced Trauma Life Support courses is appreciated by students, and the involvement of anaesthetists, general practitioners and other specialists as instructors is successful. Course rating was influenced by chosen specialty, sex and language of the students, and this should be taken into consideration when evaluating course modules and instructors.


Advanced Cardiac Life Support/education , Clinical Competence , Curriculum , Multilingualism , Patient Care Team , Wounds and Injuries , Analysis of Variance , Cooperative Behavior , Europe , Female , Health Knowledge, Attitudes, Practice , Humans , Male , Retrospective Studies , Statistics as Topic , Surveys and Questionnaires , Switzerland
13.
Psychiatr Rehabil J ; 35(1): 65-8, 2011.
Article En | MEDLINE | ID: mdl-21768081

OBJECTIVE: This exploratory study describes the impact of a peer-run warm line on the lives of individuals with psychiatric disabilities. METHODS: Phone surveys were completed with 480 warm line callers over four years. RESULTS: Warm line callers reported a reduction in the use of crisis services and a reduction of feelings of isolation. CONCLUSIONS AND IMPLICATIONS FOR PRACTICE: The results indicate that peer-run warm lines can fill an important void in the lives of individuals living with mental illnesses. Although warm lines at any time of day are helpful, keeping warm lines running after 5pm and throughout the night provides support services not typically available after office hours and can assist with loneliness, symptom management, and the process of recovery. Warm lines staffed with appropriately trained, clinically supervised, compensated peer specialists can help round out mental health services in rural and urban communities. Future research should focus on the various implementation and funding options of this unique peer support service.


Hotlines , Mental Disorders/psychology , Mental Disorders/rehabilitation , Mental Health Services , Peer Group , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Interpersonal Relations , Interviews as Topic , Loneliness/psychology , Male , Middle Aged , New England , Social Isolation/psychology , Social Support , Young Adult
15.
Med Teach ; 32(7): 586-92, 2010.
Article En | MEDLINE | ID: mdl-20653382

This article reports on a study examining continuing professional development (CPD) for consultant doctors. The aim of the study was to identify what promotes or inhibits the effectiveness of CPD and met the following objectives: comparing and contrasting the experiences of CPD across the range of specialties; identifying and describing the range of different models of CPD employed across the different specialties and clinical contexts; considering the educational potential of reflective practice in CPD and its impact on professional practice and exploring how different professionals judge the effectiveness of current CPD practices. Using a mixture of qualitative (interviews, letters, observation) and quantitative (online questionnaire) methods, the views of CPD providers and users were surveyed. Findings suggested that the effectiveness of CPD, as inferred from the comments made by interviewees and questionnaire respondents, relates to the impact on knowledge, skills, values, attitudes, behaviours and changes in practice in the work place. The quality of CPD was seen as inextricably linked to any improvements in the quality of the professional practices required for service delivery. There was widespread consensus as to the value of learning in professional settings. There was recognition that there needs to be a move away from tick boxes to the in-depth identification of learning needs and how these can be met both within and external to the work place, with learning being adequately enabled and assessed in all locations. In conclusion, it can be said that CPD is valued and is seen as effective when it addresses the needs of individual clinicians, the populations they serve and the organisations within which they work. However, the challenge for CPD may lie in the dynamic interaction between educational opportunities and service delivery requirements, as there may be occasions where they vie with each other for resources.


Attitude of Health Personnel , Consultants , Education, Medical, Continuing/standards , Education, Medical, Continuing/economics , Education, Medical, Continuing/methods , Humans , Interviews as Topic , United Kingdom
16.
Langmuir ; 26(5): 3731-8, 2010 Mar 02.
Article En | MEDLINE | ID: mdl-20175579

A method for developing complex nanopatterns on surfaces has been developed by combining self-assembly, photolabile protecting groups, and multilayered films. An o-nitrobenzyl protecting group has been incorporated into molecular level films utilizing thiol-gold interactions. When the o-nitrobenzyl group is cleaved by ultraviolet light, a carboxylic acid terminated layer remains on the surface and is available for activation and further functionalization through amide bond formation. Using this method, multilayered films have been constructed and characterized by contact angle goniometry, cyclic voltammetry, grazing incidence infrared spectroscopy, and X-ray photoelectron spectroscopy measurements. Complex surface patterns can be achieved by creating a surface array using a photomask and then further functionalizing the irradiated area through covalent coupling. Fluorophores were attached to the deprotected regions, providing visual evidence of surface patterning using fluorescence microscopy. This approach is universal to bind moieties containing free amine groups at defined regions across a surface, allowing for the development of films with complex chemical and physicochemical properties.

17.
Resuscitation ; 80(10): 1192-6, 2009 Oct.
Article En | MEDLINE | ID: mdl-19632023

The European Trauma Course (ETC) was officially launched during the international conference of the European Resuscitation Council (ERC) in 2008. The ETC was developed on behalf of ESTES (European Society of Trauma and Emergency Surgery), EuSEM (European Society of Emergency Medicine), the ESA (European Society of Anaesthesiology) and the ERC. The objective of the ETC is to provide an internationally recognised and certified life support course, and to teach healthcare professionals the key principles of the initial care of severely injured patients. Its core elements, that differentiates it from other trauma courses, are a strong focus on team training and a novel modular design that is adaptable to the differing regional European requirements. This article describes the lessons learnt during the European Trauma Course development and provides an outline of the planned future development.


Education, Medical, Continuing , Patient Care Team , Traumatology/education , Europe , Humans , Resuscitation/education
18.
Behav Brain Res ; 202(1): 92-101, 2009 Aug 24.
Article En | MEDLINE | ID: mdl-19447285

Anxiety-related behaviors were evaluated across five tests in a sample of 277 rats from a genetically heterogeneous stock (N/Nih-HS rats), derived from an eight-way cross of inbred strains, and compared with the performance of RLA-I (high anxious) and RHA-I (low anxious) rats in the same tests. These tests either evoke unlearned (novel-cage activity (NACT), elevated "zero" maze (ZM), baseline acoustic startle response (BAS)) or learned (fear-potentiated startle (FPS), two-way active-shuttle box-avoidance acquisition (SHAV)) anxious/fearful responses. The results overall showed that unlearned anxiety responses/behaviors were predictive of behavior in learned fear (i.e. fear-potentiated startle) and conflict (i.e. two-way active avoidance acquisition) situations. Moreover, it was found that N/Nih-HS rats either resemble RLA-I rat anxiety/fear scores or fall in between those of the RLA-I (high anxious) and the RHA-I (low anxious) rat strains. An additional regression analysis (of N/Nih-HS rat data) showed significant positive influences of (unlearned) baseline startle response, risk assessment (i.e. stretch-attend) behavior and activity (5min) in a novel cage on SHAV acquisition, while baseline startle and entries into the open section of the elevated 'zero' maze test of anxiety were the main variables influencing FPS. This indicates that startle responses may have a facilitating role in the rat's active responses in the two-way active (shuttlebox) avoidance acquisition. The results of this behavioral evaluation of N/Nih-HS rats show that unconditioned anxiety (e.g. in the ZM test) predicts learned fear-related responses (e.g. FPS and SHAV) to some extent, while a positive association is also observed between BAS and SHAV. These findings are discussed in terms of their potential usefulness for present and future neurobehavioral and genetic studies of fearfulness/anxiety.


Anxiety/psychology , Avoidance Learning , Fear/psychology , Analysis of Variance , Animals , Exploratory Behavior , Male , Maze Learning , Rats , Rats, Inbred Strains , Reaction Time , Reflex, Startle , Regression Analysis , Risk Assessment , Species Specificity
19.
Int J Palliat Nurs ; 14(8): 396-400, 2008 Aug.
Article En | MEDLINE | ID: mdl-19023956

This article will outline the achievements of a project group as they translate the recommendations set out in the UK National Institute for Health and Clinical Excellence (NICE) guidance on spiritual care provision in clinical practice (NICE, 2004). It was evident that there was an opportunity to offer a comprehensive, competency-based course that developed recognition of the spiritual care needs of patients with cancer and their carers. A two-day experiential programme was devised that included role play, the evidence base, theory and fun, resulting in the acquisition of tacit and explicit knowledge. The course was based around the following tenets: Spiritual issues are broader than religious ones and include a quest for meaning in the illness, resolution of old conflicts and integration of past life experiences (Barraclough, 1994). We cannot know others except by knowing ourselves (Carrither, 1992). It is hoped that by providing holistic training that stimulates the growth of an individual's spirituality and allows them to identify their spiritual needs, we can increase understanding, awareness, confidence and knowledge in ways that can have a real application within the workplace, enabling spiritual care provision to become realistically integral to care.


Education, Continuing , Health Plan Implementation , Neoplasms/therapy , Palliative Care , Spirituality , Curriculum , Educational Measurement , Humans , Neoplasms/psychology , United Kingdom
20.
Anal Chem ; 80(20): 7670-7, 2008 Oct 15.
Article En | MEDLINE | ID: mdl-18811215

Analytical gold electrodes were polished mechanically and electrochemically and the true area of the electrode surface was measured by quantitative oxidative/reductive cycling of the electrode. A roughness factor for each electrode was determined from the ratio of the true area to the geometric area. The roughness is fully described by a combination of microscopic roughness (up to tens of nanometers) and macroscopic roughness (on the order of hundreds of nanometers) terms. The electrodes were then derivatized with a self-assembled monolayer (SAM) of dodecanethiol or a thioalkane azacrown and characterized by impedance spectroscopy. The behavior of the electrodes was modeled with either a Helmholtz or Randles equivalent circuit (depending on the SAM used) in which the capacitance was replaced with a constant phase element. From the model, an effective capacitance and an alpha factor that quantifies the nonideality of the SAM capacitance was obtained. The effective capacitance divided by the roughness factor yields the capacitance per unit true area, which is only a function of microscopic roughness. The relationship between this capacitance and the alpha factor indicates that microscopic roughness predominantly affects the nonideality of the film while macroscopic roughness predominantly affects the magnitude of the film's capacitance. Understanding the contribution of the electrode topography to the magnitude and ideality of the SAM capacitance is important in the construction of SAM-based capacitive sensors because it predicts the importance of electrode-electrode variations.


Gold/chemistry , Alkanes/chemistry , Electrochemistry , Electrodes , Microscopy, Atomic Force , Sulfhydryl Compounds/chemistry , Surface Properties
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