To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Although widely used in cardiology, relation of heart failure biomarkers to cardiac haemodynamics in patients with CHD (and in particular with pulmonary insufficiency undergoing pulmonary valve replacement) remains unclear. We hypothesised that the cardiac function biomarkers N-terminal pro-brain natriuretic peptide (NT-proBNP), soluble suppressor of tumorigenicity 2, and galectin-3 would have significant associations to right ventricular haemodynamic derangements.
Consecutive patients ( n = 16) undergoing cardiac catheterisation for transcatheter pulmonary valve replacement were studied. NT-proBNP, soluble suppressor of tumorigenicity 2, and galectin-3 levels were measured using a multiplex enzyme-linked immunosorbent assay from a pre-intervention blood sample obtained after sheath placement. Spearman correlation was used to identify significant correlations (p ≤ 0.05) of biomarkers with baseline cardiac haemodynamics. Cardiac MRI data (indexed right ventricular and left ventricular end-diastolic volumes and ejection fraction) prior to device placement were also compared to biomarker levels.
NT-proBNP and soluble suppressor of tumorigenicity 2 were significantly correlated (p < 0.01) with baseline mean right atrial pressure and right ventricular end-diastolic pressure. Only NT-proBNP was significantly correlated with age. Galectin-3 did not have significant associations in this cohort. Cardiac MRI measures of right ventricular function and volume were not correlated to biomarker levels or right heart haemodynamics.
NT-proBNP and soluble suppressor of tumorigenicity 2, biomarkers of myocardial strain, significantly correlated to invasive pressure haemodynamics in transcatheter pulmonary valve replacement patients. Serial determination of soluble suppressor of tumorigenicity 2, as it was not associated with age, may be superior to serial measurement of NT-proBNP as an indicator for timing of pulmonary valve replacement.
We investigated intestinal trichomonads in western lowland gorillas, central chimpanzees and humans cohabiting the forest ecosystem of Dzanga-Sangha Protected Area in Central African Republic, using the internal transcribed spacer (ITS) region and SSU rRNA gene sequences. Trichomonads belonging to the genus Tetratrichomonas were detected in 23% of the faecal samples and in all host species. Different hosts were infected with different genotypes of Tetratrichomonas. In chimpanzees, we detected tetratrichomonads from ‘novel lineage 2’, which was previously reported mostly in captive and wild chimpanzees. In gorillas, we found two different genotypes of Tetratrichomonas. The ITS region sequences of the more frequent genotype were identical to the sequence found in a faecal sample of a wild western lowland gorilla from Cameroon. Sequences of the second genotype from gorillas were almost identical to sequences previously obtained from an anorexic French woman. We provide the first report of the presence of intestinal tetratrichomonads in asymptomatic, apparently healthy humans. Human tetratrichomonads belonged to the lineage 7, which was previously reported in domestic and wild pigs and a domestic horse. Our findings suggest that the ecology and spatial overlap among hominids in the tropical forest ecosystem has not resulted in exchange of intestinal trichomonads among these hosts.
The penetration depth of 1-12 keV electrons in most materials is less than one micron and the characteristic soft x-rays that are produced can be used to identify the elements present in the surface. Varying the energy of the incident electron beam enables the depth of analysis to be controlled.
Soft x-rays often exhibit large 'chemical effects' (changes in peak profile and peak position) which can he correlated with chemical changes. A study of such effects for each element present in the sample surface, as a function of electron-beam energy, can in some cases, permit changes in the chemical state (valency - coordination number-spin state etc.) to be determined as a function of depth.
Such analyses can be carried out either in a conventional x-ray spectrometer in which the x-ray tube has been replaced by a gas-discharge source, or in a spectrometer in which the sample is bombarded with electrons from a normal electron gun. In this paper these techniques are outlined and some applications reviewed:- the analysis of oxide layers on aluminium and steel, the analysis of aluminium-nitride layers produced by MOCVD on gallium arsenide, the analysis of silica fiims (with added boron and phosphorus oxides) on silicon and the analysis of zinc-oxide films on glass.
OBJECTIVES/SPECIFIC AIMS: The central goal of this proposal is to characterize the mechanisms that mediate success or failure of immature intestinal barrier in necrotizing enterocilitis. METHODS/STUDY POPULATION: To do this, I will utilize stem cell derived human intestinal organoids (HIOs), an innovative model of the immature intestine, and a cohort of bacterial isolates collected from premature infants who developed NEC to interrogate the cause-effect relationship of these strains on maintenance of the intestinal barrier. I hypothesize that the epithelial response to bacterial colonization is strain-dependent and results in differences in inflammatory signaling that shape epithelial barrier function in the immature intestine. RESULTS/ANTICIPATED RESULTS: Preliminary data shows that colonization of HIOs with different bacteria leads to species-specific changes in barrier function, and some species selectively damage the epithelial barrier while others enhance epithelial barrier function. I have identified key inflammatory signals that serve as central drivers of intestinal barrier function. DISCUSSION/SIGNIFICANCE OF IMPACT: Characterization of this process is expected to substantially advance scientific understanding of early events in NEC pathogenesis and lead to new opportunities for targeted therapeutic intervention to accelerate barrier maturation or prevent hyperinflammatory reactivity in the neonatal intestine. The research proposed in this application represents an entirely novel approach to studying host-microbial interactions in the immature. Conceptually, this novel translational approach will help to define the pivotal role of colonizing bacteria in initiating epithelial inflammation in NEC patients.
Formation of a low barrier back contact plays a critical role in improving the photoconversion efficiency of the CdTe solar cells. Incorporating a buffer layer to minimize the band bending at the back of the CdTe device can significantly lower the barrier for the hole current, improving open circuit voltage (VOC) and the fill factor. Over the past years, researchers have incorporated the both ZnTe and Te as buffer layers to improve CdTe device performance. Here we compare device performance using these two materials as buffer layers at the back of CdTe devices. We show that using Te in contact to CdTe results in higher performance than using ZnTe in contact to the CdTe. Low temperature current density-voltage measurements show that Te results is a lower barrier with CdTe than ZnTe, indicating that Te has better band alignment, resulting in less downward bending in the CdTe at the back interface, than ZnTe does.
The preconception, pregnancy and immediate postpartum and newborn periods are times for mothers and their offspring when they are especially vulnerable to major stressors – those that are sudden and unexpected and those that are chronic. Their adverse effects can transcend generations. Stressors can include natural disasters or political stressors such as conflict and/or migration. Considerable evidence has accumulated demonstrating the adverse effects of natural disasters on pregnancy outcomes and developmental trajectories. However, beyond tracking outcomes, the time has arrived for gathering more information related to identifying mechanisms, predicting risk and developing stress-reducing and resilience-building interventions to improve outcomes. Further, we need to learn how to encapsulate both the quantitative and qualitative information available and share it with communities and authorities to mitigate the adverse developmental effects of future disasters, conflicts and migrations. This article briefly reviews prenatal maternal stress and identifies three contemporary situations (wildfire in Fort McMurray, Alberta, Canada; hurricane Harvey in Houston, USA and transgenerational and migrant stress in Pforzheim, Germany) where current studies are being established by Canadian investigators to test an intervention. The experiences from these efforts are related along with attempts to involve communities in the studies and share the new knowledge to plan for future disasters or tragedies.
Kochia [Bassia scoparia (L.) A. J. Scott] is one of the most troublesome weeds throughout the North American Great Plains. Herbicides such as glyphosate and dicamba have been used widely to control B. scoparia for decades. However, many B. scoparia populations have evolved resistance to these herbicides due to selection. Especially, dicamba-resistant B. scoparia populations are often also found to be glyphosate-resistant. The objective of this research was to determine whether these two herbicide resistances are linked in B. scoparia. Reciprocal crosses were performed between glyphosate- and dicamba-resistant (GDR) and glyphosate- and dicamba-susceptible (GDS) B. scoparia to produce F1 and F2 progeny. Two F1 and seven F2 progeny families were screened with various doses of dicamba or glyphosate. All the F1 progeny survived both dicamba and glyphosate treatments. Chi-square analyses of F2 progeny suggest (1) glyphosate and dicamba resistances in B. scoparia are inherited via single, dominant nuclear genes; and (2) glyphosate- and dicamba-resistant genes are not linked. Thus, the dicamba and glyphosate resistances appear to have evolved independently due to intense selection but do not seem to spread together.
Maternal insufficiency during fetal development can have long-lasting effects on the offspring, most notably on nephron endowment. In polycystic kidney disease (PKD), variability in severity of disease is observed and maternal environment may be a modifying factor. In this study, we first established that in a rodent model of PKD, the Lewis polycystic kidney (LPK) rat’s nephron numbers are 25% lower compared with wildtype animals. We then investigated the effects of prenatal and postnatal maternal environment on phenotype and nephron number. LPK pups born from and raised by homozygous LPK dams (control) were compared with LPK pups cross-fostered onto heterozygous LPK dams to improve postnatal environment; with LPK pups born from and raised by heterozygous LPK dams to improve both prenatal and postnatal environment and with LPK pups born from and raised by Wistar Kyoto-LPK heterozygous dams to improve both prenatal and postnatal environment on a different genetic background. Improvement in both prenatal and postnatal environment improved postnatal growth, renal function and reduced blood pressure, most notably in animals with different genetic background. Animals with improved postnatal environment only showed improved growth and blood pressure, but to a lesser extent. All intervention groups showed increased nephron number compared with control LPK. In summary, prenatal and postnatal environment had significant effect in delaying progression and reducing severity of PKD, including nephron endowment.
Photoluminescence (PL) spectroscopy has been used to study the defect levels in thin film copper indium diselenide (CuInSe2, CIS) which we are developing as the absorber layer for the bottom cell of a monolithically grown perovskite/CuInSe2 tandem solar cell. Temperature and laser power dependent PL measurements of thin film CIS for two different Cu/In ratios (0.66 and 0.80) have been performed. The CIS film with Cu/In = 0.80 shows a prominent donor-to-acceptor peak (DAP) involving a shallow acceptor of binding energy ∼22 meV, with phonon replica at ∼32 meV spacing. In contrast, PL measurement of CIS film for Cu/In = 0.66 taken at 20 K exhibited an asymmetric and broad PL spectrum with peaks at 0.845 eV and 0.787 eV. Laser intensity dependent PL revealed that the observed peaks 0.845 eV and 0.787 eV shift towards higher energy (aka j-shift) at ∼11.7 meV/decade and ∼ 8 meV/decade with increase in laser intensity respectively. The asymmetric and broad spectrum together with large j-shift suggests that the observed peaks at 0.845 eV and 0.787 eV were related to band-to-tail (BT) and band-to-impurity (BI) transition, respectively. Such a band-tail-related transition originates from the potential fluctuation of defect states at low temperature. The appearance of band related transition in CIS film with Cu/In = 0.66 is the indicator of the presence of large number of charged defect states.
Seven half-day regional listening sessions were held between December 2016 and April 2017 with groups of diverse stakeholders on the issues and potential solutions for herbicide-resistance management. The objective of the listening sessions was to connect with stakeholders and hear their challenges and recommendations for addressing herbicide resistance. The coordinating team hired Strategic Conservation Solutions, LLC, to facilitate all the sessions. They and the coordinating team used in-person meetings, teleconferences, and email to communicate and coordinate the activities leading up to each regional listening session. The agenda was the same across all sessions and included small-group discussions followed by reporting to the full group for discussion. The planning process was the same across all the sessions, although the selection of venue, time of day, and stakeholder participants differed to accommodate the differences among regions. The listening-session format required a great deal of work and flexibility on the part of the coordinating team and regional coordinators. Overall, the participant evaluations from the sessions were positive, with participants expressing appreciation that they were asked for their thoughts on the subject of herbicide resistance. This paper details the methods and processes used to conduct these regional listening sessions and provides an assessment of the strengths and limitations of those processes.
Herbicide resistance is ‘wicked’ in nature; therefore, results of the many educational efforts to encourage diversification of weed control practices in the United States have been mixed. It is clear that we do not sufficiently understand the totality of the grassroots obstacles, concerns, challenges, and specific solutions needed for varied crop production systems. Weed management issues and solutions vary with such variables as management styles, regions, cropping systems, and available or affordable technologies. Therefore, to help the weed science community better understand the needs and ideas of those directly dealing with herbicide resistance, seven half-day regional listening sessions were held across the United States between December 2016 and April 2017 with groups of diverse stakeholders on the issues and potential solutions for herbicide resistance management. The major goals of the sessions were to gain an understanding of stakeholders and their goals and concerns related to herbicide resistance management, to become familiar with regional differences, and to identify decision maker needs to address herbicide resistance. The messages shared by listening-session participants could be summarized by six themes: we need new herbicides; there is no need for more regulation; there is a need for more education, especially for others who were not present; diversity is hard; the agricultural economy makes it difficult to make changes; and we are aware of herbicide resistance but are managing it. The authors concluded that more work is needed to bring a community-wide, interdisciplinary approach to understanding the complexity of managing weeds within the context of the whole farm operation and for communicating the need to address herbicide resistance.
Wide bandgap Cd1-xZnxTe (CZT) and Cd1-xMgxTe (CMT) have drawn attention as top cells in tandem devices. These materials allow tuning of the band gap over a wide range by controlling the Zn or Mg concentration with little alteration to the base CdTe properties. Historically, CdS has been used as a heterojunction partner for CZT or CMT devices. However, these devices show a significant lower open circuit voltage (VOC) than expected for wide bandgap absorbers. Recent modelling work suggests that poor band alignment between the CdS emitter and absorber results in a high concentration of holes at the interface, which increased recombination and limits the VOC. This recombination should be exacerbated for wider bandgap absorbers such as CZT and CMT. In this study, we use numerical simulations with SCAPS-1D software to investigate the band alignment in the front contacts for wider bandgap CdTe based absorbers. Results show that by replacing the CdS with a wide bandgap emitter layer, the VOC can be greatly improved, though under certain conditions, the fill factor remains sensitive to the location of the emitter conduction band. As a result, different transparent front contacts were also investigated to determine a device structure required to produce a high performance CZT or CMT top-cell for tandems devices.
We present the defect analysis by photoluminescence (PL) spectroscopy of CdSexTe1-x thin films, grown with varying Se content by a co-sputtered deposition method. We observe a peak at 1.203 eV in the CdSexTe1-x film for x = 0.21, which shifts towards higher energies with increase in laser power. This peak was assigned to a donor-to-acceptor (DAP) transition, with a measured j-shift of ∼4.7 meV/decade. Temperature dependent PL intensity measurements confirm that the observed DAP peak involves a shallow defect state of binding energy ∼34.7 meV. In contrast, a free-to-bound (FB) peak at 1.294 eV involving a shallow defect of binding energy ∼18.3 meV was observed in the CdSexTe1-x film for x = 0.14. Additionally, we observe band edge emission at 1.452 eV and 1.448 eV in CdSexTe1-x films for x = 0.14 and x = 0.21 respectively. Our analysis shows that the Se concentration not only changes the band gap energy of the resulting CdSexTe1-x alloy thin film, but also modifies the nature of the dominant observed defect emission.
Increasing the band gap of cadmium telluride (CdTe) from 1.48 eV to > 2 eV can be achieved by alloying CdTe with ZnTe. Like CdTe, the alloyed films are expected to allow for low cost production, suggesting that Cd1-xZnxTe could be an ideal top cell for mass produced tandem devices. However, the CdCl2 activation of the alloyed films results in a significant loss of Zn, thereby reducing the bandgap. In this study, we demonstrate a novel CdCl2 activation method that does not result in significant Zn loss. By performing the activation step in a closed, inert environment we are able to avoid oxidation of the Zn in the Cd1-xZnxTe film; furthermore, by including sacrificial Zn in the container, an overpressure of ZnCl2 forms limiting the amount of ZnCl2 formed in the film. Both x-ray diffraction, optical measurements, and Auger spectroscopy show that the CdCl2 treatment with no flowing gas minimizes the loss of Zn from the CZT alloy.
Background: EVT is now recommended as standard of care for stroke in Canada, but its implementation still poses challenges. We studied the delivery of EVT in our hospital, a participanting site in the ESCAPE trial, which serves the province of Nova Scotia. Methods: Patients who underwent EVT December 2011 – December 2016 were identified prospectively. Demographics, process measures, imaging characteristics (Alberta Stroke Program Early CT Score [ASPECTS], collateral score, Thrombolysis in Cerebral Infarction [TICI] score), and outcomes, including modified Rankin score [mRS] ~ 90 days post-EVT, were collected retrospectively. Effectiveness was assessed by comparison with outcomes in the ESCAPE trial. Results: 91 patients (M:F= 48:43; mean age 64 years) presented to hospital after 194 min ± 230 min from last seen normal. In 58%, the ASPECTS was >7. 80% had good/intermediate collaterals. Alteplase was administered to 72% (75% in ESCAPE, p=0.97). EVT mean duration was 70 min ± 62 min. Successful recanalization (≥TICI 2b) was achieved in 76% (vs 72.4% in ESCAPE, p= 0.97). Among the 54 patients recanalized, mRS scores of 0-2, 3-5 and 6 were seen in 57.4, 24.1 and 14.8% respectively; ESCAPE comparators 53, 37 and 10%, p=0.96, 0.86 and 0.91. Conclusions: EVT at our hospital yielded results similar to the ESCAPE trial.
Introduction: Approximately 2-3 percent of emergency department (ED) visits are due to eye-related complaints, adding to the ED workload. Many of these could be seen instead by an optometrist who specializes in the examination, diagnosis and treatment of eye-related disorders. We sought to determine the proportion of ED patients with isolated eye-related complaints that could be managed by an optometrist. Methods: We performed an administrative database study and descriptive analysis of all patients presenting to Calgary EDs with eye-related complaints during a one-year period. We determined optometry eligibility by reviewing discharge diagnoses and assessing whether that condition was within the Alberta Association of Optometrys (AAO) defined scope of practice. Patients were considered ineligible if their condition was related to bites, stings, thermal burns, assault, MVA or operative complications; if they required hospitalization or referral to a non-eye specialist (e.g. neurology); if they had associated headache, dizziness, syncope, hypertension, neurologic abnormality (e.g. diplopia); if they had facial cellulitis, orbital infections, adverse drug effects, or if they underwent observation in the ED because of concerns about a cardiac or neurological condition. Results: In 2015, 7686 patients were seen in Calgarys 5 EDs with eye related complaints. Of these, 76.2% were optometry-eligible and 75% of optometry-eligible patients arrived during day or evening hours (0800-2100). The most common presenting complaints were visual disturbance (24.8%), redness (22.1%), and pain or photophobia (16.4%). Optometry-eligible patients waited an average of 110 min and had an ED LOS of 149 min. Conclusion: Approximately 3 in every 4 patients seen in the ED for eye related complaints could alternatively be seen by an optometrist. Further research is required to establish the feasibility of diversion to an optometrist from the ED for eye-related complaints.
Introduction: Emergency Departments (EDs) are frequently the first point of entry to access health services for First Nation (FN) members. In Alberta, FN members visit EDs at almost double the rate of non-FN persons. Furthermore, preliminary evidence demonstrates differences in ED experience for FN members as compared to the general population. The Alberta First Nations Information Governance Centre, Maskwacis Health Services, Yellowhead Tribal Council, Treaty 8 First Nations of Alberta, and Alberta Health Services are working together to research FN members ED experiences and concerns. Methods: This is participatory research guided by a two-eyed seeing approach that acknowledges the equal value of both Western and Indigenous worldviews. FN and non-FN leaders researchers are full partners in the development of the research project. Six sharing circles will be held in February 2018 across Alberta, with Elders, FN patients, FN and non-FN clinicians and FN and non-FN administrators. Sharing circles are similar to focus groups, but emphasize everyone having a turn to speak and demonstrating respect among participants in accordance with FN protocols. Elders will select the questions for discussion based on topics that arose in initial team meetings. Sharing circle discussions will be audio recorded and transcribed. Analysts will include both Western and Indigenous worldview researchers, who will collaboratively interpret findings. Elders will review, discuss, contextualize and expand upon study findings. The research is also guided by FN principles of Ownership, Control, Access, and Possession of FN information. It is through these principles that First Nation research projects can truly be classified as FN lead and driven. Results: Based on initial team meeting discussions, results of sharing circles are expected to provide insights on issues such as: healing, patient-provider communication (verbal and non-verbal), shared decision making, respect for patient preferences, experiences leading to trust or distrust, understandings of wait times and triage, times when multiple (repeat) ED presentations occur, distances travelled for care, choosing specific EDs when seeking care, impacts of stereotypes about FN patients, and racism and reconciliation. Conclusion: Understanding FN ED experience and bringing FN perspectives to Western conceptions of the goals and provision of ED care are important steps toward reconciliation.
Introduction: With the current opioid crisis in Canada, presentations of acute opioid withdrawal (AOW) to emergency departments (ED) are increasing. Undertreated symptoms may result in relapse, overdose and death. Buprenorphine/naloxone (bup/nal) is a partial opioid agonist/antagonist used to mitigate symptoms of AOW, approved by Health Canad in 2007 for opioid use disorder. It is superior to clonidine, and increases follow up with addiction treatment programs when initiated in the ED. Nevertheless, in our inner-city ED in 2014, bup/nal was rarely prescribed. We aimed to increase ED physician prescribing of bup/nal for AOW by 50% over a 26-month period. Methods: Commencing in 2014, an interprofessional team of ED physicians, nurses (RN), pharmacists and QI specialists collaborated to improve the care of patients with AOW. PDSA cycles included: (1) needs assessment of emergency physicians knowledge and practices in 2014; (2) Grand Rounds and a web based information sheet in 2015; (3) ED stocking of bup/nal; (4) convenience order set to standardize AOW management; (5) Grand Rounds in 2016 and (6) peer-coaching for RNs, including case-based discussions and pocket card cognitive aids. The outcome was the number of times bup/nal was prescribed per month by ED physicians between Sept, 2015 and Oct, 2017. Data included the prescriber and use of order set as the process measure. The balancing measure was the number of patients referred to the Addiction Medicine Team who subsequently received bup/nal. Results: Bup/nal was prescribed by ED physicians 70 times, and 14 times by the Addiction Medicine Team. With each PDSA cycle, there was an increase in prescribing, with no significant shifts or trends. By all physicians, the median number of prescriptions per month was 3, and increased from 2 to 4 prescriptions/month after nursing education. There was a smaller increase in the median from 2 to 3 prescriptions/month by ED physicians alone. The order set was used 97% of the time. Conclusion: Bup/nal is safe, effective, and increases follow up with addiction programs for comprehensive assessment and treatment planning. We met our goal of increasing bup/nal prescribing in the ED for AOW by 50%. Moreover, prescribing increased by 100% with the addition of patients who received bup/nal after a referral to the Addiction Medicine Team. The intervention with the greatest impact was RN education, demonstrating that peer-coaching and teaching by an interprofessional team is key to changing practice. Unfortunately, overall prescribing remains low, and ED physicians may still be hesitant to prescribe bup/nal and defer to the specialists. It is unclear if this is due to a low number of patients presenting with AOW, patients with contraindications to bup/nal, or ED physician factors. The next step is an audit of all patients with AOW to see what percentage of those eligible are treated with bup/nal. A follow up survey to determine ongoing barriers will inform further PDSA cycles.
Methods of obtaining large grain size and high crystallinity in absorber materials play an important role in fabrication of high-performance methylammonium lead iodide (MAPbI3) perovskite solar cells. Here we study the effect of adding small concentrations of Cd2+, Zn2+, and Fe2+salts to the perovskite precursor solution used in the single-step solution fabrication process. Enhanced grain size and crystallinity in MAPbI3 films were obtained by using 0.1% of Cd2+ or Zn2+in the precursor solution. Consequently, solar cells constructed with Cd- and Zn-doped perovskite films show a significant improvement in device performance. These results suggest that the process may be an effective and facile method to fabricate high-efficiency perovskite photovoltaic devices.