How good are we at managing acute kidney injury in hospital?

Introduction. Acute kidney injury (AKI) is a common clinical problem associated with adverse outcomes. This study identifies the incidence of AKI in two UK district general hospitals’ without on-site renal services and assesses AKI management and level of nephrologist input. Methods. The AKIN classification was used to identify 1020 AKI patients over 6 months. Data were collated on patient demographics, AKI management and referral to nephrology and intensive care services. Short/long-term renal outcomes were investigated. Patients were followed up for 14 months post-discharge. Results. Incidence of hospital-based AKI was 6.4%. Mean patient age was 73 years. There was 28.1% acute in-hospital mortality with a further 21.6% 14-month mortality. Only 8.3% of patients were referred to nephrology services for in-hospital review, and only 8.1% had outpatient nephrology follow-up. Compliance with the AKI National Confidential Enquiry into Patient Outcomes and Deaths (NCEPOD) recommendations was poor with 32.8% of patients having renal imaging and 15% of patients having acid–base status assessed. NCEPOD compliance improved with nephrology input. Patients referred to nephrology were likely to be younger with pre-existing CKD and severe AKI. 10.5% of AKI episodes were unrecognized. Forty percent of those with unrecognized AKI, (compared with 15% of recognized AKI) developed de novo or progression of pre-existing CKD. Conclusion. AKI in DGHs is mostly managed without nephrology input. There are significant shortcomings in AKI recognition and management in this setting. This is associated with poor mortality and long-term CKD. This study supports a need to improve the teaching and training of front-line medical staff in identifying AKI. Additionally, implementation of AKI e-alert systems may encourage early recognition and provide a prompt for renal referral

The impacts of extreme climatic events on pastoralists and predators in East African rangelands

Climate change is likely to bring changes in climate variability, precipitation and increase the frequency, intensity, spatial extent and duration of extreme climatic events (XCEs). XCEs are influenced by a wide range of factors, including anthropogenic climate change, natural climate variability, and socioeconomic development. This is particularly relevant to African arid and semi-arid rangelands because of the spectacular levels of biodiversity they sustain against a backdrop of endemic poverty and vulnerability for the people whose home they are. Climate change does not work alone but in synergy with other well-known stressors, in particular habitat loss and fragmentation. These stressors as well as other factors such as changes in land use and land cover, increase in population and spread of settlements confine biodiversity to small fragmented areas and restrict people’s use and mobility. In addition, climate change will likely exacerbate already social, political and economic impacts of many rural poor, undermining human security and affecting all levels of biodiversity. As XCEs are projected to increase in this region, this thesis places itself within the growing body of literature that evaluates the effects of impacts of XCEs. This thesis used a mixed method approach to understand and evaluate the impacts of recent XCEs on pastoralists and large carnivores in Kenya. This thesis finds that pastoralists suffer enormous livestock losses during XCEs when compared to non-XCEs. In response to the increase in frequency and severity of impacts, pastoralists are responding in new ways to try to minimise the effects. Large carnivores were more likely to choose land uses that pastoralists also used more often during the XCEs. Habitat fragmentation, restriction in mobility and increases in XCEs frequency, will likely create a situation that could potentially increase interactions between pastoralists and predators, intensifying human-wildlife conflict in this region

Simplified mathematical model of proton exchange membrane fuel cell based on horizon fuel cell stack

This paper presents a simplified zero-dimensional mathematical model for a self-humidifying proton exchange membrane (PEM) fuel cell stack of 1 kW. The model incorporates major electric and thermodynamic variables and parameters involved in the operation of the PEM fuel cell under different operational conditions. Influence of each of these parameters and variables upon the operation and the performance of the PEM fuel cell are investigated. The mathematical equations are modeled by using Matlab–Simulink tools in order to simulate the operation of the developed model with a commercial available 1 kW horizon PEM fuel cell stack (H-1000), which is used for the purposes of model validation and tuning of the developed model. The model can be extrapolated to higher wattage fuel cells of similar arrangements. New equation is presented to determine the impact of using air to supply the PEM fuel cell instead of pure oxygen upon the concentration losses and the output voltage when useful current is drawn from it

Structural Requirements for Initiation of Translation by Internal Ribosome Entry within Genome-Length Hepatitis C Virus RNA

Cap-independent translation of hepatitis C virus (HCV) RNA is mediated by an internal ribosomal entry segment (IRES) located within the 5' nontranslated RNA (5'NTR), but previous studies provide conflicting views of the viral sequences which are required for translation initiation. These discrepancies could have resulted from the inclusion of less than full-length 5'NTR in constructs studied for translation or destabilization of RNA secondary structure due to fusion of the 5'NTR to heterologous reporter sequences. In an effort to resolve this confusion, we constructed a series of mutations within the 5'NTR of a nearly full-length 9.5-kb HCV cDNA clone and examined the impact of these mutations on HCV translation in vitro in rabbit reticulocyte lysates and in transfected Huh-T7 cells. The inclusion of the entire open reading frame in HCV transcripts did not lead to an increase in IRES-directed translation of the capsid and E1 proteins, suggesting that the nonstructural proteins of HCV do not include a translational transactivator. However, in reticulocyte lysates programmed with full-length transcripts, there were multiple aberrent translation initiation sites resembling those identified in some picornaviruses. The deletion of nucleotides (nt) 28-69 of the 5'NTR (stem-loop IIa) sharply reduced capsid translation both in vitro and in vivo. A small deletion mutation involving nt 328-334, immediately upstream of the initiator AUG at nt 342, also resulted in a nearly complete inhibition of translation, as did the deletion of multiple intervening structural elements. An in-frame 12-nt insertion placed within the capsid-coding region 9 nt downstream of the initiator AUG strongly inhibited translation both in vitro and in vivo, while multiple silent mutations within the first 42 nt of the open reading frame also reduced translation in reticulocyte lysates. Thus, domains II and III of the 5'NTR are both essential to activity of the IRES, while conservation of sequence downstream of the initiator AUG is required for optimal IRES-directed translation

Performance loss of proton exchange membrane fuel cell due to hydrophobicity loss in gas diffusion layer: Analysis by multiscale approach combining pore network and performance modelling

Loss of hydrophobicity in the gas diffusion layers (GDL) is sometimes suggested as a potential mechanism to explain in part the performance loss of PEMFC. The present study proposes a numerical methodology to analyse this effect by combining pore network modelling (PNM) and performance modelling (PM): the PNM/PM approach. PNM allows simulating the decrease of through-plane gas diffusion coefficient in the GDL as a function of the hydrophobicity loss, which is taken into account through the increase in the fraction of hydrophilic pores in GDL. Then PM based on Darcy equations allows simulating performance loss of PEMFC as a function of gas diffusion decay. This coupling shows that the loss of hydrophobic treatment increases flooding, decreases performance, and increases current density heterogeneities between inlet and outlet of the cell. Interestingly, this degradation is found to be highly non-linear, mainly because of the non-linear influence of the fraction of hydrophilic pores on gas diffusion (this is due to the existence of a percolation threshold associated with the hydrophilic pore sub-network) as well as the non-linear behaviour of electrochemistry with gas diffusion. This study also shows that the loss of hydrophobicity in a GDL is a very suitable candidate to explain performance loss rates that are classically observed during long-term tests. The proposed methodology may also help linking other local properties of components to fuel cell global performance

Predicting malignancy in thyroid nodules: feasibility of a predictive model integrating clinical, biochemical, and ultrasound characteristics

Background: Although the majority of thyroid nodules are benign the process of excluding malignancy is challenging and sometimes involves unnecessary surgical procedures. We explored the development of a predictive model for malignancy in thyroid nodules by integrating a combination of simple demographic, biochemical, and ultrasound characteristics. Methods: Retrospective case-record review. We reviewed records of patients with thyroid nodules referred to our institution from 2004 to 2011 (n = 536; female 84 %, mean age 51 years). All malignancy was proven histologically while benign disease was either confirmed histologically, or on cytology with minimum 36-month observation period. We focused on the following predictors: age, sex, smoking status, thyroid hormones (FT4 and TSH) and nodule characteristics on ultrasound. Variables were included in a multivariate logistic regression and bootstrap analyses were used to confirm results. Results: Independent predictors of malignancy in the fully adjusted model were TSH (OR 1.53, 95 % CI 1.10, 2.12, p = 0.01), male gender (OR 3.45, 95 % CI 1.33, 8.92, p = 0.01), microcalcifications (OR 6.32, 95 % CI 2.82, 14.1, p < 0.001), and irregular nodule margins (OR 5.45, 95 % CI 1.61, 18.6, p = 0.006) Bootstrap analyses strengthened these associations and a parsimonious analysis consisting of these variables and age-group demonstrated an area under the curve of 0.77. A predictive score was sensitive (86.9 %) at low scores and highly specific (94.87 %) at higher scores for distinguishing benign from malignant disease. Conclusions: A predictive model for malignancy using a combination of clinical, biochemical, and radiological characteristics may support clinicians in reducing unnecessary invasive procedures in patients with thyroid nodules