Clay mineralogy, chemistry, and diagenesis of late devonian K-bentonite occurrences in northwestern Turkey

Thin beds of tephra (K-bentonites) formed by the diagenesis of volcanic ash are exposed within the limestone-dolomitic limestone successions of the Yilanli formation at Zonguldak and Bartin in northwestern Turkey. They were deposited on the Middle Devonian-Lower Carboniferous shallow carbonate platform of the Zonguldak terrane. In this study, K-bentonite samples collected from Gavurpinari and Yilanli Burnu limestone quarries are investigated in order to reveal their mineralogical and geochemical characteristics and diagenetic evolution. Illite is the major clay mineral in the studied K-bentonites. Additionally, kaolinite and mixed-layer illite-smectite are identified in some samples. The nonclay minerals calcite, dolomite, quartz, gypsum, feldspar, pyrite, and zircon are also found. Crystal-chemical characteristics (Kiibler index, d060 values, and polytypes of illites) from two different sampling locations do not show significant variations. Kiibler index values for the Yilanli Burnu and Gavurpinari sampling locations, 0.47-0.93 (average: 0.71 A°29) and 0.69-0.77 (average: 0.72 A°29), respectively, indicate that illites were affected by high-grade diagenetic conditions. The swelling (or smectite) component (~5%), crystallite size (N = 10-20 nm), and polytype (2M1 > 1Md) data of illites support the same conditions. Illite d060 values of 1.491-1.503 A correspond to a range of octahedral Mg+Fe values of 0.27-0.51 atoms per formula, indicating a composition between end-member muscovite and phengite unit. Trace and rare earth element-based chemical classification of the K-bentonite samples revealed that composition of original volcanic ash is basaltic. Illitization took place by fixation of K from volcanic minerals and ash, and diffusion of elements (Mg+Fe) into and out of the beds during diagenesis. Mineralogical-chemical data point out that these K-bentonites evolved in high-grade diagenetic conditions (approximately 100-150 °C) from the products of volcanic eruptions of disputed sources and distances during the Late Devonian time. © 2015 TÜBİTAK

The Effects of Cinnamaldehyde, Monensin and Quebracho Condensed Tannin on Rumen Fermentation, Biohydrogenation and Bacteria in Continuous Culture System

The objective of this experiment was to evaluate the effects of different feed additives (cinnamaldehyde, monensin, and quebracho condensed tannin extract) on fermentation, trans fatty acids (FA) formation and selected strains of rumen bacteria. Four continuous culture systems were used in 4 × 4 Latin square designs with 4 periods of 10 days each. Treatment diets were: control diet (44:56 forage to concentrate; CON), control plus cinnamaldehyde (CIN) at 400 mg/L, control plus monensin (MON) at 12 mg/L, and control with quebracho condensed tannin extract (QTAN) at 100 g/kg of diet (DM basis). Fermenters were fed treatment diets three times daily at 120 g/day and overflow (effluent) samples were collected from each fermenter on days 8, 9 and 10 of each period to estimate nutrients digestibility and FA composition. On day 10 of each period, three samples were collected from each fermenter at 3 and 6 h post morning feeding for volatile fatty acids (VFA), ammonia-N and bacterial analyses. Compared with the CON diet, feed additives had no effects (P \u3e 0.05) on apparent dry matter (DM), neutral detergent fiber (NDF) and organic matter (OM) digestibility but apparent protein digestibility decreased (P \u3c 0.01) with the QTAN and CIN diets. Compared with the CON diet, the concentration of acetate decreased (P \u3c 0.05) with the MON and CIN diets. The concentration of propionate increased (P \u3c 0.05) with the MON and QTAN diets and was greatest with the MON diet. Ammonia-N concentration decreased (P \u3c 0.01) with all feed additives and was least with the QTAN diet. The concentration of C18:0 decreased (P \u3c 0.01) with the three feed additives and was least with the MON diet. Concentration of trans C18:1 and vaccenic acid (VA) increased (P \u3c 0.05) with the MON and CIN diets and was greatest with the MON diet. Compared with the CON diet, the concentration of c9t11CLA increased (P \u3c 0.05) only with the QTAN diet. The DNA abundance of Butyrivibrio proteoclasticum decreased (P \u3c 0.05) with the MON and CIN diets while the DNA abundance for Butyrivibrio VA increased (P \u3c 0.05) with all feed additives compared with the CON diet. Feed additives had no effects (P \u3e 0.05) on the DNA abundance of Anaerovibrio lipolytica and Butyrivibrio SA. In conclusion, results demonstrate that the feed additives used in this study affected the fermentation and biohydrogenation process. Addition of feed additives reduced the formation of C18:0 but only MON and CIN increased VA formation. MON and CIN effects on VA formation may in part be explained by their effects on B. proteoclasticum

Using Computer Simulation for Reducing the Appointment Lead-Time in a Public Pediatric Outpatient Department

Pediatric outpatient departments aim to provide a pleasant, effective and continuing care to children. However, a problem in these units is the long waiting time for children to receive an appointment. Prolonged appointment lead-time remains a global challenge since it results in delayed diagnosis and treatment causing increased morbidity and dissatisfaction. Additionally, it leads to an increased number of hospitalization and emergency department visits which augments the financial burden faced by healthcare systems. Despite these considerations, the studies directly concentrating on the reduction of appointment lead-time in these departments are largely limited. Therefore, this paper proposes the application of Discrete-event Simulation (DES) approach to evaluate potential improvement strategies aiming at reducing average appointment lead-time. Initially, the outpatient department is characterized to effectively identify the main activities, process variables, interactions, and system constraints. After data collection, input analysis is conducted through intra-variable independence, homogeneity and goodness-of-fit tests followed by the creation of a simulation model representing the real pediatric outpatient department. Then, Mann-Whitney tests are used to prove whether the model was statistically comparable with the real-world system. After this, the outpatient department performance is assessed in terms of average appointment lead-time and resource utilization. Finally, three improvement scenarios are assessed technically and financially, to determine if they are viable for implementation. A case study of a mixed-patient type environment in a public pediatric outpatient department has been explored to validate the proposed methodology. Statistical tests demonstrate that appointment lead-time in pediatric outpatient departments may be meaningfully minimized using this approach. © 2019, Springer Nature Switzerland AG

How simulation modelling can help reduce the impact of COVID-19

Modelling has been used extensively by all national governments and the World Health Organisation in deciding on the best strategies to pursue in mitigating the effects of COVID-19. Principally these have been epidemiological models aimed at understanding the spread of the disease and the impacts of different interventions. But a global pandemic generates a large number of problems and questions, not just those related to disease transmission, and each requires a different model to find the best solution. In this article we identify challenges resulting from the COVID-19 pandemic and discuss how simulation modelling could help to support decision-makers in making the most informed decisions. Modellers should see the article as a call to arms and decision-makers as a guide to what support is available from the simulation community

Applying multi-phase DES approach for modelling the patient journey through accident and emergency departments

Accident and Emergency departments (A&ED) are in charge of providing access to patients requiring urgent acute care. A&ED are difficult to model due to the presence of interactions, different pathways and the multiple outcomes that patients may undertake depending on their health status. In addition, public concern has focused on the presence of overcrowding, long waiting times, patient dissatisfaction and cost overruns associated with A&ED. There is then a need for tackling these problems through developing integrated and explicit models supporting healthcare planning. However, the studies directly concentrating on modelling the A&EDs are largely limited. Therefore, this paper presents the use of a multi-phase DES framework for modelling the A&ED and facilitating the assessment of potential improvement strategies. Initially, the main components, critical variables and different states of the A&ED are identified to correctly model the entire patient journey. In this step, it is also necessary to characterize the demand in order to categorize the patients into pipelines. After this, a discrete-event simulation (DES) model is developed. Then, validation is conducted through the 2-sample t test to demonstrate whether the model is statistically comparable with the real-world A&ED department. This is followed by the use of Markov phase-type models for calculating the total costs of the whole system. Finally, various scenarios are explored to assess their potential impact on multiple outcomes of interest. A case study of a mixed-patient environment in a private A&E department is provided to validate the effectiveness of the multi-phase DES approach

Sedentary Behaviour Intervention as a Personalised Secondary Prevention Strategy (SIT LESS) for patients with coronary artery disease participating in cardiac rehabilitation: rationale and design of the SIT LESS randomised clinical trial.

Patients with coronary artery disease (CAD) are more sedentary compared with the general population, but contemporary cardiac rehabilitation (CR) programmes do not specifically target sedentary behaviour (SB). We developed a 12-week, hybrid (centre-based+home-based) Sedentary behaviour IntervenTion as a personaLisEd Secondary prevention Strategy (SIT LESS). The SIT LESS programme is tailored to the needs of patients with CAD, using evidence-based behavioural change methods and an activity tracker connected to an online dashboard to enable self-monitoring and remote coaching. Following the intervention mapping principles, we first identified determinants of SB from literature to adapt theory-based methods and practical applications to target SB and then evaluated the intervention in advisory board meetings with patients and nurse specialists. This resulted in four core components of SIT LESS: (1) patient education, (2) goal setting, (3) motivational interviewing with coping planning, and (4) (tele)monitoring using a pocket-worn activity tracker connected to a smartphone application and providing vibrotactile feedback after prolonged sedentary bouts. We hypothesise that adding SIT LESS to contemporary CR will reduce SB in patients with CAD to a greater extent compared with usual care. Therefore, 212 patients with CAD will be recruited from two Dutch hospitals and randomised to CR (control) or CR+SIT LESS (intervention). Patients will be assessed prior to, immediately after and 3 months after CR. The primary comparison relates to the pre-CR versus post-CR difference in SB (objectively assessed in min/day) between the control and intervention groups. Secondary outcomes include between-group differences in SB characteristics (eg, number of sedentary bouts); change in SB 3 months after CR; changes in light-intensity and moderate-to-vigorous-intensity physical activity; quality of life; and patients' competencies for self-management. Outcomes of the SIT LESS randomised clinical trial will provide novel insight into the effectiveness of a structured, hybrid and personalised behaviour change intervention to attenuate SB in patients with CAD participating in CR. Trial registration number NL9263

Myocardial energy depletion and dynamic systolic dysfunction in hypertrophic cardiomyopathy

Evidence indicates that anatomical and physiological phenotypes of hypertrophic cardiomyopathy (HCM) stem from genetically mediated, inefficient cardiomyocyte energy utilization, and subsequent cellular energy depletion. However, HCM often presents clinically with normal left ventricular (LV) systolic function or hyperkinesia. If energy inefficiency is a feature of HCM, why is it not manifest as resting LV systolic dysfunction? In this Perspectives article, we focus on an idiosyncratic form of reversible systolic dysfunction provoked by LV obstruction that we have previously termed the 'lobster claw abnormality' — a mid-systolic drop in LV Doppler ejection velocities. In obstructive HCM, this drop explains the mid-systolic closure of the aortic valve, the bifid aortic pressure trace, and why patients cannot increase stroke volume with exercise. This phenomenon is characteristic of a broader phenomenon in HCM that we have termed dynamic systolic dysfunction. It underlies the development of apical aneurysms, and rare occurrence of cardiogenic shock after obstruction. We posit that dynamic systolic dysfunction is a manifestation of inefficient cardiomyocyte energy utilization. Systolic dysfunction is clinically inapparent at rest; however, it becomes overt through the mechanism of afterload mismatch when LV outflow obstruction is imposed. Energetic insufficiency is also present in nonobstructive HCM. This paradigm might suggest novel therapies. Other pathways that might be central to HCM, such as myofilament Ca2+ hypersensitivity, and enhanced late Na+ current, are discussed