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The Wellens pattern is an electrocardiographic finding seen in patients with chest pain and atherosclerotic coronary artery disease and is described as a symmetrical T-wave inversion or biphasic T-wave inversion in precordial leads. The deep inversion of the precordial T wave is a sign associated with various etiologies, including left ventricular hypertrophy, vasospasm, and pulmonary embolism. We present the case of a patient who debuts with chest pain and electrocardiographic findings consistent with the Wellens and McGinn-White patterns, who was subsequently diagnosed with intermediate-risk pulmonary embolism after ruling out obstructive coronary artery disease. We discussed the differential diagnostic approach to T-wave inversion as a sign associated with high-risk conditions. [ABSTRACT FROM AUTHOR]

• Model the relationship between straight-forward and non-tractable variables with piece-wise linearizable machine learning. • Extend the standard constraint learning methodology by including chance constraints. • Provide open-access software for practitioners. • Methodology is tested with two real-world case studies. When dealing with optimization problems, decision-makers often face high levels of uncertainty associated with partial information, unknown parameters, or complex relationships between these and the problem decision variables. In this work, we develop a novel Chance Constraint Learning (CCL) methodology with a focus on mixed-integer linear optimization problems, which combines and extends ideas from the literature on chance constraint and constraint learning. While constraint learning aims to model the functional relationship between straight-forward and non-tractable decision variables through the embedding of predictive models within the optimization problem, chance constraints set a probabilistic confidence level for a single or a set of constraints to be fulfilled. One of the main issues when establishing a learned constraint arises when we need to set further bounds for its response variable: the fulfillment of these is directly related to the accuracy of the predictive model and its probabilistic behavior. Therefore, the proposed CCL makes use of piece-wise linearizable machine learning models to estimate conditional quantiles of learned variables, providing a data-driven solution for chance constraints and adding probabilistic guarantees over constraints for learned variables. Open access software has been developed for use by practitioners. Furthermore, the benefits of CCL have been tested in two real-world case studies, demonstrating how robustness is added to optimal solutions when probabilistic bounds are established for learned constraints. [ABSTRACT FROM AUTHOR]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.ahj.2008.10.003 Byline: Paul T.L. Chiam (a)(b), Carlos E. Ruiz (a) Abstract: Aortic stenosis (AS) is currently the most common valvular abnormality in developed countries. The gold standard treatment of severe symptomatic AS is surgical aortic valve replacement. Mechanical valves were initially the prostheses of choice; with improvement of surgical technique and results, and increased durability of bioprosthetic valves, there has been a trend toward increasing use of bioprostheses. Concurrently, percutaneous technology has advanced exponentially, and the first human percutaneous aortic valve replacement (PAVR) became a reality in 2002. Various groups have now reported their early experiences with PAVR using different technologies. This new treatment modality is evolving very rapidly. There are currently 2 devices being used in clinical trials; several more devices have first-in-man results and others in preclinical development. It appears that PAVR will most likely become a viable option for selected patients in the near future. For these technologies to continue to improve and benefit patients, cross-specialty teamwork is vital. Treatment of severe AS will greatly evolve as these new and emerging technologies improve. Enhancement in device designs and increasing operator experience will make this technology safer and allow its application to a wider patient population. Author Affiliation: (a) Department of Cardiac and Vascular Interventional Services, Lenox Hill Heart and Vascular Institute of New York, NY (b) Department of Cardiology, National Heart Center, Singapore, Singapore Article History: Received 4 June 2008; Accepted 2 October 2008 Article Note: (footnote) The authors are solely responsible for the design and conduct of this study, all study analyses, and drafting and editing of the manuscript.

Demand for food is growing along with the human population, leading to an increase in plant production. Many crops are pollinated by insects, so the global demand for managed pollinators is also increasing. The honey bee has traditionally been considered the main provider of crop pollination services. For providing it beekeepers seasonally transport hives to different locations after the flowering of different crops. These movements could be detrimental to pollinators by: i) stressing honey bees, making them more susceptible to pathogens and parasites; ii) spreading bee parasites and pathogens across locations; iii) increasing the transmission of parasites and pathogens between managed and wild pollinators and vice versa (spillover and spillback, respectively). To understand the impact of migratory beekeeping on bee health, we conducted a systematic review to identify the main trends and provide a complete picture of existing knowledge on the subject. We found 52 studies analysing pathogen-related impacts of migratory beekeeping on honey bees. However, only 16 investigations tested the effect of migratory practices on the prevalence and spread of pathogens and parasites. We found no studies that assessed the impact of migratory beekeeping on the occurrence and spread of pests and diseases in wild bees. In general, migratory beekeeping tends to increase the prevalence of pathogens and parasites in honey bee colonies. However, the results were very heterogeneous, probably due to several uncontrolled underlying factors such as management, biological and geographical factors, and the interactions between them. In conclusion, there is an urgent need for studies to assess the impact of migratory beekeeping on bee health, given the current global bee decline and the expected increase in migratory beekeeping due to climate change and crop pollination demand. [Display omitted] • Migratory beekeeping may affect the health of both managed and wild bees. • Only 16 studies compare the prevalence of pathogens between migratory and stationary hives. • Results are heterogeneous due to the complex interaction of the underlying factors. • Overall, the prevalence of pathogens and parasites increased in migratory honey bees. • The impact of migratory beekeeping on the health of wild bees is unknown. [ABSTRACT FROM AUTHOR]

Angiography, serial X-raying of blood vessels after injection of a dye, can show the contours of blood vessels, while angioscopy, which involves threading a microscopic tube into vessels, and ultrasound imaging can provide information about abnormalities of vessel surfaces and walls. These techniques are not usually used together. Two cases are reported in which all three methods were used before and after percutaneous transluminal angioplasty (PTA), in which a balloon catheter is threaded into a constricted blood vessel and then inflated. The first patient was a 72-year-old man with claudication (leg pain during activity) who had no pulse in the right foot. Angiography showed 75 percent narrowing of a leg artery due to atherosclerosis, while angioscopy showed a clot. The clot was aspirated. Ultrasound confirmed atherosclerotic narrowing and suggested calcification of the area, so that high pressures would be needed during balloon inflation. Following inflation, only a 25 percent narrowing remained, and angioscopy and ultrasound showed tearing of the arterial lining. The second case was a 75-year-old man with similar symptoms. All three imaging techniques indicated the patient had an atherosclerotic plaque next to an area of complete blockage. Following catheter inflation, the area was found to be 65 percent constricted, and angioscopy and ultrasound but not angiography indicated that the plaque had a disrupted surface. The study demonstrates that angiography is best for analysis of an entire area of blood vessels, while angioscopy is best for evaluating the vessel surface, and ultrasound provides information about the vessel wall. The last two techniques are not yet easy to use, but led to alterations in treatment in a fourth of the cases where they were employed. Use of angiography with the other techniques should lead to improved patient treatment and should improve understanding of disease processes in blood vessels. (Consumer Summary produced by Reliance Medical Information, Inc.)

Balloon catheters are routinely used to widen coronary arteries which are constricted due to coronary artery disease. Single heart valves which have narrowed as a result of rheumatic heart disease have also been successfully treated using this technique. A case is reported in which three heart valves were successfully widened during a single procedure. The patient was a 35-year-old woman with congestive heart failure related to rheumatic heart disease. Balloon dilation was chosen over valve replacement due to the rheumatic disease and because she was of child-bearing age. The valve area was successfully widened for all three valves, which resulted in improved heart function and blood pressure. The patient's functional status remained much improved one year after treatment. The diagnosis and rationale for treatment are discussed. (Consumer Summary produced by Reliance Medical Information, Inc.)

The use of machine-learning methods helps to improve decision-making in different fields. In particular, the idea of bridging predictions (predictive models) and prescriptions (optimization problems) is gaining attention within the scientific community. One of the main ideas to address this trade-off is the Constraint Learning (CL) methodology, where the structure of the machine learning model can be treated as a set of constraints to be embedded within the optimization problem, establishing the relationship between a direct decision variable x and a response variable y. However, most CL approaches have focused on making point predictions, not considering the statistical and external uncertainty faced in the modeling process. In this paper, we extend the CL methodology to deal with uncertainty in the response variable y. The novel Distributional Constraint Learning (DCL) methodology makes use of a piece-wise linearizable neural network-based model to estimate the parameters of the conditional distribution of y (dependent on decisions x and contextual information), which can be embedded within mixed-integer optimization problems. In particular, we formulate a stochastic optimization problem by sampling random values from the estimated distribution by using a linear set of constraints. In this sense, DCL combines both the predictive performance of the neural network method and the possibility of generating scenarios to account for uncertainty within a tractable optimization model. The behavior of the proposed methodology is tested in the context of electricity systems, where a Virtual Power Plant seeks to optimize its operation, subject to different forms of uncertainty, and with price-responsive consumers. • Extent CL methodology in MIO addressing uncertainty in response variables. • DCL uses neural nets to estimate and embed conditional distributions in MIO. • Develop open access (DistCL) tool to employ the DCL methodology. • Test the validity of the approach in a Virtual Power Plant problem. [ABSTRACT FROM AUTHOR]

Porous materials have numerous applications in industry. Elements such as gears, pins, filters, bearings, and connecting rods, among others, are examples of parts that can be manufactured from these materials, where the presence of varying loads may cause a catastrophic failure. The shakedown analysis is a useful tool to establish the safe conditions for the operation of a structural or mechanical component subjected to varying loads. However, the shakedown analysis of porous materials has received little attention and a general formulation for this problem is not available. This paper presents a static and a mixed variational principle for the shakedown analysis of porous materials and the corresponding numerical solution via the finite element method. A yield function for porous material is obtained from the specific strain energy combined with a relationship between the relative density and the applied hydrostatic pressure. The shakedown analysis performed in this paper is based on a mixed variational principle which gives rise to an optimization problem. The solution provides, not only the largest amplification factor for the domain of load variation, but also the residual stresses and velocities fields. The discretization of the mixed variational principle is performed by the finite element method and uses a triangle with six nodes which permits a quadratic interpolation of velocities together with a linear interpolation of stresses. The validation of the numerical procedure is accomplished by comparing the present simulation with previously published results and analytical solutions for the residual stresses and amplification factor. The finite element method provided good solutions for all the presented examples. The presented variational formulation may be used to obtain the safe condition for mechanical parts made of porous materials and subjected to variable loads. Moreover, it can be used to estimate the relative density distribution in the parts. [ABSTRACT FROM AUTHOR]

The distributed integration of renewable energy sources plays a central role in the decarbonization of economies. In this regard, energy communities arise as a promising entity to coordinate groups of proactive consumers (prosumers) and incentivize investment on clean technologies. However, the uncertain nature of renewable energy generation, residential loads, and trading tariffs pose important challenges, both at the operational and economic levels. We study how this management can be directly undertaken by an arbitrageur that, making use of an adequate price-based demand response (real-time pricing) system, serves as an intermediary with the central electricity market to coordinate different types of prosumers under risk aversion. In particular, we consider a sequential futures and spot market where the aggregated shortage or excess of energy within the community can be traded. We aim to study the impact of new hydrogen production and storage technologies on community operation and risk management. These interactions are modeled as a game theoretical setting in the form of a stochastic two-stage bilevel optimization problem, which is later reformulated without approximation as a single-level mixed-integer linear problem (MILP). An extensive set of numerical experiments based on real data is performed to study the operation of the energy community under different technical and economical conditions. Results indicate that the optimal involvement in futures and spot markets is highly conditioned by the community's risk aversion and self-sufficiency levels. Moreover, the external hydrogen market has a direct effect on the community's internal price-tariff system, and depending on the market conditions, may worsen the utility of individual prosumers. • The operation of an energy community with renewables and storage is modeled. • A price tariff system is effective to coordinate prosumers under risk aversion. • Forward trading is highly conditioned by the level of electrical self-sufficiency. • The mix of electricity and hydrogen markets may worsen the utility of prosumers. [ABSTRACT FROM AUTHOR]

The VARC (Valve Academic Research Consortium) for transcatheter aortic valve replacement set the standard for selecting appropriate clinical endpoints reflecting safety and effectiveness of transcatheter devices, and defining single and composite clinical endpoints for clinical trials. No such standardization exists for circumferentially sutured surgical valve paravalvular leak (PVL) closure. This document seeks to provide core principles, appropriate clinical endpoints, and endpoint definitions to be used in clinical trials of PVL closure devices. The PVL Academic Research Consortium met to review evidence and make recommendations for assessment of disease severity, data collection, and updated endpoint definitions. A 5-class grading scheme to evaluate PVL was developed in concordance with VARC recommendations. Unresolved issues in the field are outlined. The current PVL Academic Research Consortium provides recommendations for assessment of disease severity, data collection, and endpoint definitions. Future research in the field is warranted. [ABSTRACT FROM AUTHOR]

Subclinical leaflet thrombosis was recently described in a randomized trial of transcatheter aortic valve replacement. It was subsequently demonstrated in a series of registries that this was a commonly observed imaging finding seen in all transcatheter and surgical bioprostheses. The phenomenon has aroused considerable interest due to the as-yet-undefined risk for later clinical events and the possibility of pharmacological intervention with anticoagulation. Subclinical leaflet thrombosis is easily detected noninvasively by technically suitable computed tomography (CT) with a high degree of concordance to transesophageal echocardiography findings. The CT hallmarks were noted to be hypoattenuated leaflet thickening (HALT) associated with reduced leaflet motion (RELM). The combination of HALT and RELM signified hypoattenuation affecting motion, the standardized imaging endpoint used. This paper describes the systematic CT evaluation methodology that was devised during the Portico trial investigation and U.S. Food and Drug Administration submission; it also highlights the need for an ongoing discussion among experts to enable, with the help of the Valve Academic Research Consortium, standardization of reporting of this imaging finding to cater to the present and future needs of clinical trials. [ABSTRACT FROM AUTHOR]

Background The Society of Thoracic Surgeons (STS)/American College of Cardiology Transcatheter Valve Therapy (TVT) Registry captures all procedures with Food and Drug Administration–approved transcatheter valve devices performed in the United States, and is mandated as a condition of reimbursement by the Centers for Medicaid & Medicare Services. Objectives This annual report focuses on patient characteristics, trends, and outcomes of transcatheter aortic and mitral valve catheter-based valve procedures in the United States. Methods We reviewed data for all patients receiving commercially approved devices from 2012 through December 31, 2015, that are entered in the TVT Registry. Results The 54,782 patients with transcatheter aortic valve replacement demonstrated decreases in expected risk of 30-day operative mortality (STS Predicted Risk of Mortality [PROM]) of 7% to 6% and transcatheter aortic valve replacement PROM (TVT PROM) of 4% to 3% (both p < 0.0001) from 2012 to 2015. Observed in-hospital mortality decreased from 5.7% to 2.9%, and 1-year mortality decreased from 25.8% to 21.6%. However, 30-day post-procedure pacemaker insertion increased from 8.8% in 2013 to 12.0% in 2015. The 2,556 patients who underwent transcatheter mitral leaflet clip in 2015 were similar to patients from 2013 to 2014, with hospital mortality of 2% and with mitral regurgitation reduced to grade ≤2 in 87% of patients ( p < 0.0001). The 349 patients who underwent mitral valve-in-valve and mitral valve-in-ring procedures were high risk, with an STS PROM for mitral valve replacement of 11%. The observed hospital mortality was 7.2%, and 30-day post-procedure mortality was 8.5%. Conclusions The TVT Registry is an innovative registry that that monitors quality, patient safety and trends for these rapidly evolving new technologies. [ABSTRACT FROM AUTHOR]

Objectives This study sought to evaluate transcatheter aortic valve replacement (TAVR) in bicuspid aortic valve (BAV) aortic stenosis (AS), with a particular emphasis on TAVR-directed bicuspid aortic valve imaging (BAVi) of morphological classification. Background TAVR has been used to treat BAV-AS but with heterogeneous outcomes and uncertainty regarding the relevance of morphology. Methods In 14 centers in the United States, Canada, Europe, and Asia, 130 BAV-AS patients underwent TAVR. Baseline cardiac computed tomography (CT) was analyzed by a dedicated Corelab. Outcomes were assessed in line with Valve Academic Research Consortium criteria. Results Bicommissural BAV (vs. tricommissural) accounted for 68.9% of those treated in North America, 88.9% in Europe, and 95.5% in Asia (p = 0.003). For bicommissural bicuspids, non-raphe type (vs. raphe type) BAV accounted for 11.9% of those treated in North America, 9.4% in Europe, and 61.9% in Asia (p < 0.001). Overall rates of 30-day mortality (3.8%) and cerebrovascular events (3.2%) were favorable and similar among anatomical subsets. The rate of new permanent pacemaker insertion was high (26.2%) and similar between balloon-expandable (BE) and self-expanding (SE) designs (BE: 25.5% vs. SE: 26.9%; p = 0.83); there was a trend to greater permanent pacemaker insertion in BE TAVR in the presence of coronary cusp fusion BAV morphology. Paravalvular aortic regurgitation (PAR) ≥ moderate was 18.1% overall but lower at 11.5% in those with pre-procedural CT. In the absence of pre-procedural CT, there was an excess of PAR in BE TAVR that was not the case in those with a pre-procedural CT; SE TAVR required more post-dilation. Predictors of PAR included intercommissural distance for bicommissural bicuspids (odd ratio [OR]: 1.37; 95% confidence interval [CI]: 1.02 to 1.84; p = 0.036) and lack of a baseline CT for annular measurement (OR: 3.03; 95% CI: 1.20 to 7.69; p = 0.018). Conclusions In this multicenter study, TAVR achieved favorable outcomes in patients with pre-procedural CT, with the exception of high permanent pacemaker rates for all devices and shapes. [ABSTRACT FROM AUTHOR]

Objectives The purpose of this study was to investigate changes in the use of transcatheter aortic valve replacement (TAVR) relative to surgical aortic valve replacement (SAVR) and to examine relative 1-year TAVR and SAVR outcomes in 2011 to 2012 in a population-based setting. Background TAVR has become a popular option for patients with severe aortic stenosis, particularly for higher-risk patients. Methods New York’s Cardiac Surgery Reporting System was used to identify TAVR and SAVR volumes and to propensity match TAVR and SAVR patients using numerous patient risk factors contained in the registry to compare 1-year mortality rates. Mortality rates were also compared for different levels of patient risk. Results The total number of aortic valve replacement patients increased from 2,291 in 2011 to 2,899 in 2012, an increase of 27%. The volume of SAVR patients increased by 7.1% from 1,994 to 2,135 and the volume of TAVR patients increased 157% from 297 to 764. The percentage of SAVR patients that were at higher risk (≥3% New York State [NYS] score, equivalent to a Society of Thoracic Surgeons score of about 8%) decreased from 27% to 23%, and the percentage of TAVR patients that were at higher risk decreased from 83% to 76%. There was no significant difference in 1-year mortality between TAVR and SAVR patients (15.6% vs. 13.1%; hazard ratio [HR]: 1.30 [95% confidence interval (CI): 0.89 to 1.92]). There were no differences among patients with NYS score <3% (12.5% vs. 10.2%; HR: 1.42 [95% CI: 0.68 to 2.97]) or among patients with NYS score ≥3% (17.1% vs. 14.5%; HR: 1.27 [95% CI: 0.81 to 1.98]). Conclusions TAVR has assumed a much larger share of all aortic valve replacements for severe aortic stenosis, and the average level of pre-procedural risk has decreased substantially. There are no differences between 1-year mortality rates for TAVR and SAVR patients. [ABSTRACT FROM AUTHOR]

The vast majority of newly synthesized acetylcholinesterase (AChE) molecules do not assemble into catalytically active oligomeric forms and are rapidly degraded intracellularly by the endoplasmic reticulum-associated protein degradation pathway. We have previously shown that AChE in skeletal muscle is regulated in part post-translationally by the availability of the noncatalytic subunit collagen Q, and others have shown that expression of a 17-amino acid N-terminal proline-rich attachment domain of collagen Q is sufficient to promote AChE tetramerization in cells producing AChE. In this study we show that muscle cells, or cell lines expressing AChE catalytic subunits, incubated with synthetic proline-rich attachment domain peptides containing the endoplasmic reticulum retrieval sequence KDEL take up and retrogradely transport them to the endoplasmic reticulum network where they induce assembly of AChE tetramers. The peptides act to enhance AChE folding thereby rescuing them from reticulum degradation. This enhanced folding efficiency occurs in the presence of inhibitors of protein synthesis and in turn increases total cell-associated AChE activity and active tetramer secretion. Pulsechase studies of isotopically labeled AChE molecules show that the enzyme is rescued from intracellular degradation. These studies provide a mechanistic explanation for the large scale intracellular degradation of AChE previously observed and indicate that simple peptides alone can increase the production and secretion of this critical synaptic enzyme in muscle tissue. [ABSTRACT FROM AUTHOR]

Transcatheter therapies in structural heart disease have evolved tremendously over the past 15 years. Since the introduction of the first balloon-expandable valves for stenotic lesions with implantation in the pulmonic position in 2000, treatment for valvular heart disease in the outflow position has become more refined, with newer-generation devices, alternative techniques, and novel access approaches. Recent efforts into the inflow position and regurgitant lesions, with transcatheter repair and replacement technologies, have expanded our potential to treat a broader, more heterogeneous patient population. The evolution of multimodality imaging has paralleled these developments. Three- and 4-dimensional visualization and concomitant use of novel technologies, such as fusion imaging, have supported technical growth, from pre-procedural planning and intraprocedural guidance, to assessment of acute results and follow-up. A multimodality approach has allowed operators to overcome many limitations of each modality and facilitated integration of a multidisciplinary team for treatment of this complex patient population. [ABSTRACT FROM AUTHOR]

[Display omitted] • New approach that includes different parameters and working conditions in TEG. • Efficiency surface in terms of Resistance, segmentation, and geometric shape. • Iso efficient curves and their relation to system specifications are discussed. • Iso-efficiency and equivalent configurations for the design of the thermoelectrics. • A Carnot-like statement is proposed. A study is carried out for the efficiency of segmented thermoelectric microgenerators (μ STEGs). The study includes a) n-type and p-type double or triple segmentation and b) geometry shape factor of the thermoelements. The temperature-dependent thermoelectric properties of nanostructured materials are determined from experimental data. In addition, the impact of internal resistance, as a function of the thermoelement-geometric shape factor, on the efficiency surfaces of the μ STEGs is studied based on non-equilibrium thermodynamics. Results show that the efficiency surfaces of different μ STEGs intersect under different working conditions. The curve formed by the intersection points of the efficiency surfaces of the two thermoelectric systems is called the iso-efficiency curve. Thus, segmented thermoelectric systems with different efficiencies can reach a common efficiency for a given segmentation and geometric shape form of their thermoelements under different working conditions. The common efficiency that reaches (corresponds to) these thermoelectric systems is called Iso efficiency. The iso efficiency is reached due to the n-type and p-type material segmentation and geometric shape, which affect each thermoelement's internal resistance. Furthermore, the efficiency of a μ STEG system can be improved due to the combination of effects such as the relationship between load resistance and internal resistance when it is affected by the geometric shape, temperature difference, and segmentation. Our results allow determinate the new iso efficiency parameters with a good selection of the thermodynamic, electrical, and geometric parameters and establish guidance for other materials engineering investigations, to improve the efficiency of μ STEGs. [ABSTRACT FROM AUTHOR]