bluuebunny/crossref_metadata_2025 huggingface dataset:
Ion Channels Orchestrate Pancreatic Ductal Adenocarcinoma Progression and Therapy
Authors: Hofschröer Verena , Najder Karolina , Rugi Micol , Bouazzi Rayhana , Cozzolino Marco , Arcangeli Annarosa , Panyi Gyorgy , Schwab Albrecht
Published: January 2021

Pancreatic ductal adenocarcinoma is a devastating disease with a dismal prognosis. Therapeutic interventions are largely ineffective. A better understanding of the pathophysiology is required. Ion channels contribute substantially to the “hallmarks of cancer.” Their expression is dysregulated in cancer, and they are “misused” to drive cancer progression, but the underlying mechanisms are unclear. Ion channels are located in the cell membrane at the interface between the intracellular and extracellular space. They sense and modify the tumor microenvironment which in itself is a driver of PDAC aggressiveness. Ion channels detect, for example, locally altered proton and electrolyte concentrations or mechanical stimuli and transduce signals triggered by these microenvironmental cues through association with intracellular signaling cascades. While these concepts have been firmly established for other cancers, evidence has emerged only recently that ion channels are drivers of PDAC aggressiveness. Particularly, they appear to contribute to two of the characteristic PDAC features: the massive fibrosis of the tumor stroma (desmoplasia) and the efficient immune evasion. Our critical review of the literature clearly shows that there is still a remarkable lack of knowledge with respect to the contribution of ion channels to these two typical PDAC properties. Yet, we can draw parallels from ion channel research in other fibrotic and inflammatory diseases. Evidence is accumulating that pancreatic stellate cells express the same “profibrotic” ion channels. Similarly, it is at least in part known which major ion channels are expressed in those innate and adaptive immune cells that populate the PDAC microenvironment. We explore potential therapeutic avenues derived thereof. Since drugs targeting PDAC-relevant ion channels are already in clinical use, we propose to repurpose those in PDAC. The quest for ion channel targets is both motivated and complicated by the fact that some of the relevant channels, for example, KCa3.1, are functionally expressed in the cancer, stroma, and immune cells. Onlyin vivostudies will reveal which arm of the balance we should put our weights on when developing channel-targeting PDAC therapies. The time is up to explore the efficacy of ion channel targeting in (transgenic) murine PDAC models before launching clinical trials with repurposed drugs.
An Improved Collaborative Filtering Recommendation Algorithm Based on Retroactive Inhibition Theory
Authors: Yang Nihong , Chen Lei , Yuan Yuyu
Published: January 2021

Collaborative filtering (CF) is the most classical and widely used recommendation algorithm, which is mainly used to predict user preferences by mining the user’s historical data. CF algorithms can be divided into two main categories: user-based CF and item-based CF, which recommend items based on rating information from similar user profiles (user-based) or recommend items based on the similarity between items (item-based). However, since user’s preferences are not static, it is vital to take into account the changing preferences of users when making recommendations to achieve more accurate recommendations. In recent years, there have been studies using memory as a factor to measure changes in preference and exploring the retention of preference based on the relationship between the forgetting mechanism and time. Nevertheless, according to the theory of memory inhibition, the main factors that cause forgetting are retroactive inhibition and proactive inhibition, not mere evolutions over time. Therefore, our work proposed a method that combines the theory of retroactive inhibition and the traditional item-based CF algorithm (namely, RICF) to accurately explore the evolution of user preferences. Meanwhile, embedding training is introduced to represent the features better and alleviate the problem of data sparsity, and then the item embeddings are clustered to represent the preference points to measure the preference inhibition between different items. Moreover, we conducted experiments on real-world datasets to demonstrate the practicability of the proposed RICF. The experiments show that the RICF algorithm performs better and is more interpretable than the traditional item-based collaborative filtering algorithm, as well as the state-of-art sequential models such as LSTM and GRU.
Proof of Concept (PoC) 1.0—Implementing a Bioshading System Design Method
Authors: Oliveira Maria João de , Rato Vasco Moreira , Leitão Carla
Published: January 2021

Nature provides a remarkable database of possible adaptation strategies that can be implemented in biomimetic design of shading systems. However, at this moment, successful design methods are conditioned to a limited knowledge and ability to emulate nature’s strategies to meet corresponding functional needs. The implementation of biomimetic processes has some major challenges: (1) the search and selection among several databases of appropriate strategies adopted by nature; (2) difficulties in reading, interpreting and translating at different scales; (3) connection problems between concepts and material premises. The selection of nature models is a very common situation among architectural projects. Proof of Concept (PoC) 1.0 was the first experience of application of the Bioshading System Design Method (BSDM). BSDM is a problem-based method that guides its users since the initial architectural challenge definition, improving users’ capabilities to interpret and translate nature strategies into architecture design, until its final state of creation, it’s physical condition. This experience enabled us to validate and evolve initial decisions, based on users experience and evaluation. At the end, PoC 1.0 revealed to be a fundamental step into the final version of BSDM.
RNA-Binding Protein La Mediates TGFβ-Induced Epithelial to Mesenchymal Transition and Cancer Stem Cell Properties
Authors: Heise Tilman , Sommer Gunhild
Published: January 2021

Background: the aberrant overexpression of predominantly nuclear localizing RNA-binding protein (RBP) La contributes to proliferation, mobility, and chemoresistance of cancer cells and tumor growth in mice. Methods: studies included cancer tissue microarrays (TMAs) analyses, cancer tissue data mining, transforming growth factor β (TGFβ)-induced cancer cell plasticity studies, three dimensional sphere growth, epithelial to mesenchymal transition (EMT) assays, analysis of cancer stem cell (CSC) marker expression, and post-translational modification of cancer-associated La protein. Results: we demonstrated that significant overexpression of RBP La in lung and head and neck cancer tissue correlates with poor overall survival. Furthermore, small interfering RNA-mediated depletion of La reduced proliferation and migration of cancer cells, blocked TGFβ-induced EMT, and diminished both EMT and CSC marker expression. Rescue experiments with La wildtype but not RNA chaperone domain activity-defective La mutant increased the expression of those cancer progression markers, suggesting a critical role of La’s RNA chaperone activity in this process. La depletion in cancer cells also significantly decreased sphere growth in the presence of TGFβ. Interestingly, TGFβ treatment induced phosphorylation of La at threonine 389 (pLaT389) only in adherents but not in 3D growing cultures. Conclusion: our study suggests that the TGFβ/AKT/pLaT389 signaling pathway regulates cancer cell plasticity.
Study on Friction and Wear Properties of Zr–Cu–Ni–Al Crystalline Powder Cladding and Amorphous Composite Powder Cladding by Laser
Authors: Chen Yugan , Tao Pingjun , Zhang Weijian , Zhang Chaohan , Zhu Kunsen
Published: January 2021

In order to improve the friction and wear performance and surface hardness of AISI 1045 steel and expand its application range, this paper carried out the research on friction and wear performance and surface hardness of Zr65Al7.5Ni10Cu17.5 crystalline powder (CP) and amorphous powder (AP) after laser cladding on AISI 1045 steel surface. The results show that both CP and amorphous powder (AP) formed a cladding layer on the surface of AISI 1045 steel under laser irradiation. The thickness of the cladding layer is about 400 μm, and the thickness of the AP cladding layer is slightly larger than that of the CP cladding layer. The results show that there are many holes in the AP cladding layer, and holes can be observed at the junction with the matrix; while the CP cladding layer is well combined with the matrix and no holes are observed. The friction performance of CP cladding layer is better than that of AP cladding layer. In the wear marks of the AP cladding layer, there are bonding areas, while the wear marks of the CP cladding layer have a furrow-like morphology, and part of the matrix is exposed. The surface microhardness and average microhardness of AP cladding layer are 49% and 94% higher than that of CP cladding layer, respectively. Hardness modification has obvious advantages. The reasons for porosity, large friction coefficient and low stability of the friction experiment of the AP cladding layer are analyzed and discussed. The ideas and methods for improving the laser irradiation to achieve both high wear resistance and high strength of the AP cladding layer are proposed.
Evidence-Based Strategies for the Treatment of Peritoneal Malignancies during Health Care Resource Restriction: The COVID-19 Pandemic
Authors: Shariff Farhana , Bischof Danielle , Govindarajan Anand , Prince Rebecca , Burkes Ronald , Haase Erika , Mack Lloyd , Temple Walley , Hebbard Pamela , Boulanger-Gobeil Cindy , Giacomantonio Carman , Brind’Amour Alexandre , Sidéris Lucas , Dubé Pierre , Hamilton Trevor , MacNeill Andrea , Bouchard-Fortier Antoine , Younan Rami , McCart Andrea
Published: January 2021

Background: The COVID-19 pandemic has put enormous pressure on hospital resources, and has affected all aspects of patient care. As operative volumes decrease, cancer surgeries must be triaged and prioritized with careful thought and attention to ensure maximal benefit for the maximum number of patients. Peritoneal malignancies present a unique challenge, as surgical management can be resource intensive, but patients have limited non-surgical treatment options. This review summarizes current data on outcomes and resource utilization to help inform decision-making and case prioritization in times of constrained health care resources. Methods: A rapid literature review was performed, examining surgical and non-surgical outcomes data for peritoneal malignancies. Narrative data synthesis was cross-referenced with relevant societal guidelines. Peritoneal malignancy surgeons and medical oncologists reviewed recommendations to establish a national perspective on case triage and mitigating treatment strategies. Results and Conclusions: Triage of peritoneal malignancies during this time of restricted health care resource is nuanced and requires multidisciplinary discussion with consideration of individual patient factors. Prioritization should be given to patients where delay may compromise resectability of disease, and where alternative treatment options are lacking. Mitigating strategies such as systemic chemotherapy and/or surgical deferral may be utilized with close surveillance for disease stability or progression, which may affect surgical urgency. Unique hospital capacity, and ability to manage the complex post-operative course for these patients must also be considered to ensure patient and system needs are aligned.
Emergency Department Utilization for Patients Receiving Immune Checkpoint Inhibitors: A Retrospective Analysis of Identification and Outcomes for Those Presenting for Immune-Related Adverse Events
Authors: Holstead Ryan , Kartolo Adi , Baetz Tara
Published: January 2021

Background: Immune-related adverse events (iRAEs) are known complications of immune checkpoint inhibitors (ICIs). Early identification and management leads to improved morbidity and mortality. This study seeks to address our center’s experience with iRAEs in the emergency department (ED). Methods: We performed a retrospective review of patients treated with ICIs in 2018 and 2019 for any indication. All diagnoses of iRAEs were recorded. For all patients who presented to the ED following administration of an ICI, we assessed whether the presenting symptoms were eventually diagnosed as an iRAE. We assessed disposition, time to initiation of corticosteroids and outcomes in these patients. Results: 351 evaluable patients were treated with an ICI, 129 patients (37%) had at least one presentation to the ED, 17 of whom presented with symptoms due to a new iRAE. New iRAE diagnoses were broad, occurred after median 2 cycles, majority irAEs were grade 3 or higher (70.6%), and two patients died due to toxicity. Twelve patients were admitted to the hospital during initial presentation or at follow-up, four required ICU care. All patients required immunosuppressive therapy, and only three were later re-challenged with an ICI. Of the patients who were admitted to the hospital, median time to first dose of corticosteroid was 30.5 h (range 1–269 h). Conclusions: Patients on ICI have a significant risk of requiring an ED visit. A notable proportion of iRAEs have their first presentation at the ED and often can present in a very nonspecific manner. A standardized approach in the ED at the time of presentation may lead to improved identification and management of these patients.
Real World First-Line Treatments and Outcomes of Nab-Paclitaxel Plus Gemcitabine, mFOLFIRINOX and GEMOX in Unresectable Pancreatic Cancer from a Chinese Single Institution
Authors: Quan Qi , Wang Yixing , Wang Fenghua , Zhang Dongsheng , Chen Xiuxing , He Wenzhuo , Zhang Bei , Guo Guifang
Published: January 2021

Background: There have not been any head-to-head prospective studies to compare the effects of different chemotherapy regimens as first-line treatments for unresectable pancreatic cancer (UPC). We aimed to compare the effectiveness of nab-paclitaxel plus gemcitabine, mFOLFIRINOX and gemcitabine plus oxaliplatin (GEMOX) as first-line treatments by using real-world data from Chinese patients. Methods: We retrospectively included patients with UPC treated with nab-paclitaxel plus gemcitabine, mFOLFIRINOX or GEMOX as a first-line treatment at Sun Yat-sen University Cancer Center. Overall survival (OS), progression-free survival (PFS), objective response rate (ORR) and disease control rate (DCR) were assessed. Results: A total of 117 patients were administered nab-paclitaxel plus gemcitabine (n = 62), mFOLFIRINOX (n = 30) or GEMOX (n = 25) as first-line chemotherapy. The median OS was 11.1, 10.1 and 10.2 months (p = 0.75) in the nab-paclitaxel plus gemcitabine, mFOLFIRINOX and GEMOX, respectively. The ORR was similar among the three groups (24%, 23% and 32%, p = 0.76) and the DCR was higher in the nab-paclitaxel-gemcitabine group (82%) than the other two groups (60% and 64%, p = 0.04). The most common adverse events of grade 3 or 4 were neutropenia (32%, 28% and 5%), peripheral neuropathy (13%, 16% and 0) and fatigue (9%, 16% and 5%). Febrile neutropenia occurred in 2%, 4% and 5% of the patients in the three groups. Conclusion: In the first line treatment of UPC, our results suggest that nab-paclitaxel plus gemcitabine was associated with a higher DCR than mFOLFIRINOX or GEMOX, while all groups demonstrated similar OS, PFS and ORR.
Canadian Cancer Centre Response to COVID-19 Pandemic: A National and Provincial Response
Authors: Rittberg Rebekah , Mann Anmol , Desautels Danielle , Earle Craig C. , Navaratnam Sri , Pitz Marshall
Published: January 2021

Background: COVID-19 has spread rapidly, requiring health delivery systems to undertake dramatic transformations. To evaluate these system changes, we undertook one of the first Canadian health delivery system reviews and the first Canadian cancer centre evaluation of pandemic system modifications. Methods: Questionnaires were distributed to the Canadian Association of Provincial Cancer Agencies (CAPCA) members in order to assess changes to cancer centre services and patient management. Documentation relating to COVID-19 from the CAPCA electronic space was accessed, and all publicly available cancer centre documentation related to COVID-19 was reviewed. Results: Seven provinces completed the questionnaire and had documentation available from the CAPCA electronic space. All screening programs across Canada were suspended. In most provinces surveyed, ≥50% of outpatient appointments were occurring virtually, with <25% using video platforms. Generally, the impact on diagnostic imaging and new patient referrals correlated with the impact of COVID-19. Most provinces had a reduction in operating room availability, with chemotherapy and radiation treatments continuing. Public health modification, including personal protective equipment and screening staff, varied across the country. Conclusion: Canadian cancer centres underwent a rapid and aggressive transformation of services in response to COVID-19, with many similarities and differences across provinces. In part, this response was facilitated by communication under a national association, which in Canada remains unique to cancer. This response may serve to inform changes in other jurisdictions or disease states now and in future waves of the pandemic, as well as a record of changes for future health services and patient outcome research.
Evaluation and Management of Dyslipidemia in Patients Treated with Lorlatinib
Authors: Blais Normand , Adam Jean-Philippe , Nguyen John , Grégoire Jean C.
Published: January 2021

The use of lorlatinib, an anaplastic lymphoma kinase (ALK) inhibitor for the treatment of ALK-positive metastatic non-small cell lung cancer, is associated with dyslipidemia in over 80% of patients. Clinical trial protocols for the management of lorlatinib-associated dyslipidemia differ from clinical practice guidelines for the management of dyslipidemia to prevent cardiovascular disease, in that they are based on total cholesterol and triglyceride levels rather than on the low-density lipoprotein cholesterol and non-high-density lipoprotein cholesterol levels that form the basis of current cardiovascular guideline recommendations. In order to simplify and harmonize the management of cardiovascular risk in patients with lorlatinib, an advisory committee consisting of a medical oncologist, a cardiologist, and two pharmacists with expertise in cardiology and oncology aimed to develop a simplified algorithm, adapted from the Canadian Cardiovascular Society dyslipidemia recommendations. Recommendations for the evaluation and management of hypercholesterolemia and isolated hypertriglyceridemia in patients treated with lorlatinib are outlined. These recommendations are based on data collected in a large number of lipid-lowering therapy trials applicable to individuals with and without cancer. Considering the relatively long life expectancy and improving prognosis of patients with ALK translocations, this specific patient population should be treated as are patients without cancer and are likely to derive the same benefits from lipid-lowering therapy.
Polipharmacy and Multimorbity in Oncological Patients: An Open Challenge
Authors: Loreti Claudia , Castelli Letizia , Coraci Daniele , Fusco Augusto , Giovannini Silvia , Padua Luca
Published: January 2021

Kirkham and colleagues presented an original study about cancer survivors in Canadian population and reported that the odds of several cardiovascular disease risk factors are higher among middle-aged. Several risk factors are connected to a toxic lifestyle and are associated with cardiovascular diseases and general health status. The paper is very relevant in managing oncological patients. A particular attention should be given to some anamnestic data about the presence of other pathologies (as self-reported diabetes and hypertension) and drug therapy with particular consideration of angiotensin-converting enzyme inhibitors that present a protective action against cardiovascular events and reduce the incidence of type II diabetes. In order to identify and intervene on risk factors, clinicians should depict the pharmacological therapy taken by the study population, assuming that in the elderly this may be potentially protective on cardiovascular risk profile compared to younger cancer survivors.
COVID-19 Pandemic Stressors and Psychological Symptoms in Breast Cancer Patients
Authors: Massicotte Véronique , Ivers Hans , Savard Josée
Published: January 2021

Background. The current Coronavirus disease 2019 (COVID-19) pandemic is a highly stressful event that may lead to significant psychological symptoms, particularly in cancer patients who are at a greater risk of contracting viruses. This study examined the frequency of stressors experienced in relation to the ongoing coronavirus pandemic and its relationship with psychological symptoms (i.e., anxiety, depression, insomnia, fear of cancer recurrence) in breast cancer patients. Methods. Thirty-six women diagnosed with a non-metastatic breast cancer completed the Insomnia Severity Index, the Hospital Anxiety and Depression Scale, the severity subscale of the Fear of Cancer Recurrence Inventory, and the COVID-19 Stressors Questionnaire developed by our research team. Participants either completed the questionnaires during (30.6%) or after (69.4%) their chemotherapy treatment. Results. Results revealed that most of the participants (63.9%) have experienced at least one stressor related to the COVID-19 pandemic (one: 27.8%, two: 22.2%, three: 11.1%). The most frequently reported stressor was increased responsibilities at home (33.3%). Higher levels of concerns related to the experienced stressors were significantly correlated with higher levels of anxiety, depressive symptoms, insomnia, and fear of cancer recurrence, rs(32) = 0.36 to 0.59, all ps < 0.05. Conclusions. Cancer patients experience a significant number of stressors related to the COVID-19 pandemic, which are associated with increased psychological symptoms. These results contribute to a better understanding of the psychological consequences of a global pandemic in the context of cancer and they highlight the need to better support patients during such a challenging time.
Real World Analysis of Small Cell Lung Cancer Patients: Prognostic Factors and Treatment Outcomes
Authors: Moser Sarah Sharman , Bar Jair , Kan Inna , Ofek Keren , Cohen Raanan , Khandelwal Nikhil , Shalev Varda , Chodick Gabriel , Siegelmann-Danieli Nava
Published: January 2021

In this observational study, we assessed treatment patterns and prognostic factors in patients with small cell lung cancer (SCLC) in a large state-mandated healthcare organization in Israel. Methods: All incident cases with histologically confirmed SCLC who initiated systemic anti-cancer treatment between 2011 and 2017 were identified. Treatment patterns and overall survival (OS) were evaluated for each line of therapy. Results: A total of 235 patients were identified (61% male, median age 64 years, 95% ever smokers, 64% had extensive stage). The first-line treatment was platinum–etoposide regimen for 98.7% of the cohort. The second and third-line regimen were given to 43% and 12% of patients, respectively. Mean OS for extensive and limited stage patients was 9.1 and 23.5 months respectively. In a multivariable model, increased risk for mortality was observed among patients with an ECOG performance status (PS) of 2 compared to a PS of 0–1 for the extensive stage patients (Hazard ratio (HR) = 1.63, 95% confidence ratios (CI): 1.00–2.65); and for males compared to females for the limited stage patients (HR = 2.17; 95% CI: 1.12–4.20). Regarding all 2nd line patients in a multivariable model incorporating relevant confounding factors, demonstrated a significantly better outcome with platinum–based regimens compared to topotecan. Median survival after initiation of 2nd line in platinum-sensitive patients was longer (p = 0.056) for those re-challenged with platinum–based regimen (n = 7): 6.8mo (6.1-not reported (NR)), compared with those switched to a different treatment (n = 27): 4.5 mo (2.6–6.6) for extensive stage patients, and a non-significant difference was also observed for limited stage patients. Conclusion: To our knowledge, this is one of the largest real-world studies of SCLC patients. OS for SCLC patients was similar to that reported in clinical trials. PS for extensive stage patients and sex for limited stage patients were significant correlates of prognosis. Re-challenge of the platinum–based doublet was associated with longer OS compared to switching treatment in extensive stage patients.
Stereotactic Body Radiation Therapy (SBRT) for a Patient with a Myocardial Metastasis: A Case Report
Authors: Dhar Aneesh , Donovan Elysia , Leong Darryl , Hotte Sebastien J. , Swaminath Anand
Published: January 2021

Metastatic lesions of the heart are rare but have the potential to cause significant morbidity. We describe the case of a patient with renal cell carcinoma who presented with shortness of breath and palpitations and was found to have a metastatic myocardial lesion causing arrythmia. He received stereotactic body radiation therapy (SBRT) to alleviate symptoms and provide local control. SBRT planning was executed using a four-dimensional computed tomography (4DCT) scan to account for respiratory and cardiac motion. Images from a planning magnetic resonance imaging (MRI) scan and a gated diagnostic MRI scan of the heart were fused with the 4DCT to assist with delineating the tumour. A dose of 30 Gy in five fractions was delivered without incident. The patient’s cardiac MRI at two months post-treatment showed stability of his cardiac lesion. He subsequently died of distant disease progression, without any recurrence of his cardiac symptoms. SBRT may be considered for patients who present with a symptomatic metastatic cardiac lesion.
Has Radiotherapy Been Successfully Implemented in Alberta’s Small Cities? A Review of Alberta’s Regional Cancer Centre Network from 2010–2020
Authors: Craighead Peter S. , Ruether Dean , Martens Chandra , Grendarova Petra
Published: January 2021

The expansion of cancer services closer to home has become a major focus of publicly funded healthcare, with cancer organizations attempting to invest in smaller centers by integrating radiotherapy into these facilities. In Canada this has resulted in Ontario, British Columbia and Alberta investing in 12 expanded regional centers over the past 20 years. Quebec, Manitoba and Nova Scotia have made similar investments. Alberta’s three new centers opened in 2010, 2013 and 2021 (projected). This study examined improvements in wait times and patient throughput between 2010 and 2020, and highlighted strategies that will support the sustainability and growth of clinical activity through to 2030. Significant improvement in ready to treat wait times for radiotherapy have resulted from opening two centers, and the provincial throughput for patients requiring systemic or radiotherapy has gone up by 16%. A patient satisfaction survey demonstrated that rural patients are happy with their care and desire the provision of more of their cancer treatment closer to home. An expert panel provided recommendations on what needs to be done to stabilize recruitment and retention.
A Multi-Class Automatic Sleep Staging Method Based on Photoplethysmography Signals
Authors: Zhao Xiangfa , Sun Guobing
Published: January 2021

Automatic sleep staging with only one channel is a challenging problem in sleep-related research. In this paper, a simple and efficient method named PPG-based multi-class automatic sleep staging (PMSS) is proposed using only a photoplethysmography (PPG) signal. Single-channel PPG data were obtained from four categories of subjects in the CAP sleep database. After the preprocessing of PPG data, feature extraction was performed from the time domain, frequency domain, and nonlinear domain, and a total of 21 features were extracted. Finally, the Light Gradient Boosting Machine (LightGBM) classifier was used for multi-class sleep staging. The accuracy of the multi-class automatic sleep staging was over 70%, and the Cohen’s kappa statistic k was over 0.6. This also showed that the PMSS method can also be applied to stage the sleep state for patients with sleep disorders.
Probabilistic Models with Deep Neural Networks
Authors: Masegosa Andrés R. , Cabañas Rafael , Langseth Helge , Nielsen Thomas D. , Salmerón Antonio
Published: January 2021

Recent advances in statistical inference have significantly expanded the toolbox of probabilistic modeling. Historically, probabilistic modeling has been constrained to very restricted model classes, where exact or approximate probabilistic inference is feasible. However, developments in variational inference, a general form of approximate probabilistic inference that originated in statistical physics, have enabled probabilistic modeling to overcome these limitations: (i) Approximate probabilistic inference is now possible over a broad class of probabilistic models containing a large number of parameters, and (ii) scalable inference methods based on stochastic gradient descent and distributed computing engines allow probabilistic modeling to be applied to massive data sets. One important practical consequence of these advances is the possibility to include deep neural networks within probabilistic models, thereby capturing complex non-linear stochastic relationships between the random variables. These advances, in conjunction with the release of novel probabilistic modeling toolboxes, have greatly expanded the scope of applications of probabilistic models, and allowed the models to take advantage of the recent strides made by the deep learning community. In this paper, we provide an overview of the main concepts, methods, and tools needed to use deep neural networks within a probabilistic modeling framework.
The Broadcast Approach in Communication Networks
Authors: Tajer Ali , Steiner Avi , Shamai (Shitz) Shlomo
Published: January 2021

In this paper we review the theoretical and practical principles of the broadcast approach to communication over state-dependent channels and networks in which the transmitters have access to only the probabilistic description of the time-varying states while remaining oblivious to their instantaneous realizations. When the temporal variations are frequent enough, an effective long-term strategy is adapting the transmission strategies to the system’s ergodic behavior. However, when the variations are infrequent, their temporal average can deviate significantly from the channel’s ergodic mode, rendering a lack of instantaneous performance guarantees. To circumvent a lack of short-term guarantees, the broadcast approach provides principles for designing transmission schemes that benefit from both short- and long-term performance guarantees. This paper provides an overview of how to apply the broadcast approach to various channels and network models under various operational constraints.
Quantum Mechanics and Its Evolving Formulations
Authors: Antoine Jean-Pierre
Published: January 2021

In this paper, we discuss the time evolution of the quantum mechanics formalism. Starting from the heroic beginnings of Heisenberg and Schrödinger, we cover successively the rigorous Hilbert space formulation of von Neumann, the practical bra-ket formalism of Dirac, and the more recent rigged Hilbert space approach.
Design Parameters of a Double-Slope Solar Still: Modelling, Sensitivity Analysis, and Optimization
Authors: Yousefi Hossein , Aramesh Mohamad , Shabani Bahman
Published: January 2021

This study presents a novel, highly detailed, and accurate modelling method for calculation of the total annual solar thermal energy received by a double-slope solar still. The model is further utilized for sensitivity analysis and optimization with the help of Genetic Algorithm and TOPSIS methods. The model reveals that the main parameters that can independently affect solar energy input are the basin length, width, tilt angle, surface azimuth angle, and the glass covers’ inclination angle. The sensitivity of the annual solar energy input to all these parameters is analyzed. Moreover, all the parameters are chosen to be involved in the optimization problem. Sensitivity analysis results show that except for basin azimuth angle all other parameters significantly affect the amount of energy input to the solar still. Genetic Algorithm identified 60 optimum sets of parameters, one of which was selected by the TOPSIS method. The optimum values for the basin width, length, tilt and azimuth angles, and the inclination angles of the two glass covers are 2 m, 2 m, 8°, 180°, 80° and 67°, respectively. This design of a double-slope solar still will receive an annual total of 97.67 GJ solar energy input.
Sizing and Cost Minimization of Standalone Hybrid WT/PV/Biomass/Pump-Hydro Storage-Based Energy Systems
Authors: Alturki Fahd A. , Awwad Emad Mahrous
Published: January 2021

In this study, a standalone hybrid wind turbine (WT)/photovoltaic (PV)/biomass/pump-hydro-storage energy system was designed and optimized based on technical, economic, and environmental parameters to provide the load demand with an objective function of minimum cost of energy (COE). The constraints of the proposed approach are the loss of power supply probability, and the excess energy fraction. The proposed approach allows the combination of different sources of energy to provide the best configuration of the hybrid system. Therefore, the proposed system was optimized and compared with a WT/PV/biomass/battery storage-based hybrid energy system. This study proposes three different optimization algorithms for sizing and minimizing the COE, including the whale optimization algorithm (WOA), firefly algorithm (FF) and particle swarm optimization (PSO) and the optimization procedure was executed using MATLAB software. The outcomes of these algorithms are contrasted to select the most effective, and the one providing the minimum COE is chosen based on statistical analysis. The results indicate that the proposed hybrid WT/PV/biomass/pump-hydro storage energy system is environmentally and economically practical. Meanwhile, the outcomes demonstrated the technical feasibility of a pump-hydro energy storage system in expanding the penetration of renewable energy sources compared to other existing systems. The COE of the pumped-hydro storage hybrid system was found to be lower (0.215 $/kWh) than that with batteries storage hybrid system (0.254 $/kWh) which was determined using WOA at the same load demand.
Effect of the Foresight Horizon on Computation Time and Results Using a Regional Energy Systems Optimization Model
Authors: Thomsen Jessica , Hussein Noha Saad , Dolderer Arnold , Kost Christoph
Published: January 2021

Due to the high complexity of detailed sector-coupling models, a perfect foresight optimization approach reaches complexity levels that either requires a reduction of covered time-steps or very long run-times. To mitigate these issues, a myopic approach with limited foresight can be used. This paper examines the influence of the foresight horizon on local energy systems using the model DISTRICT. DISTRICT is characterized by its intersectoral approach to a regionally bound energy system with a connection to the superior electricity grid level. It is shown that with the advantage of a significantly reduced run-time, a limited foresight yields fairly similar results when the input parameters show a stable development. With unexpected, shock-like events, limited foresight shows more realistic results since it cannot foresee the sudden parameter changes. In general, the limited foresight approach tends to invest into generation technologies with low variable cost and avoids investing into demand reduction or efficiency with high upfront costs as it cannot compute the benefits over the time span necessary for full cost recovery. These aspects should be considered when choosing the foresight horizon.
Energy and Economic Investigation of a Biodiesel-Fired Engine for Micro-Scale Cogeneration
Authors: Perrone Diego , Algieri Angelo , Morrone Pietropaolo , Castiglione Teresa
Published: January 2021

The work aims at investigating the techno-economic performance of a biodiesel micro combined heat and power (CHP) system for residential applications. The CHP unit is based on a direct-injection compression ignition engine providing 6.7 kWel and 11.3 kWth. A 0D model is developed and validated to characterise the behaviour of the biodiesel-fired engine at full and partial load in terms of efficiency, fuel consumption, and emissions. Furthermore, non-dimensional polynomial correlations are proposed to foresee the performance of biodiesel-fuelled engines for micro-CHP applications at partial loads. Afterwards, the CHP system is adopted to satisfy the electric and thermal demand of domestic users in Southern Italy. To this purpose, a parametric analysis is performed considering a different number of apartments and operating strategies (electric-driven and thermal-driven). A bi-variable optimisation based on the primary energy saving (PES) index and payback period (PBT) permits selecting the thermal-driven strategy and five apartments as the most suitable solution. The optimal PBT and PES are equal to 5.3 years and 22.4%, respectively. The corresponding annual thermal self-consumption reaches 81.3% of the domestic request, and the thermal surplus is lower than 8%. Finally, a sensitivity analysis is adopted to define the influence of the costs of energy vectors and a cogeneration unit on the economic feasibility of the biodiesel CHP system. The analysis highlights that the investigated apparatus represents an attractive option to satisfy the energy requests in micro-scale applications, providing valuable energy and economic advantages compared to traditional energy production.
Biogas Upgrading and Ammonia Recovery from Livestock Manure Digestates in a Combined Electromethanogenic Biocathode—Hydrophobic Membrane System
Authors: Cerrillo Miriam , Burgos Laura , Bonmatí August
Published: January 2021

Anaerobic digestion process can be improved in combination with bioelectrochemical systems in order to recover energy and resources from digestates. An electromethanogenic microbial electrolysis cell (MEC) coupled to an ammonia recovery system based on hydrophobic membranes (ARS-HM) has been developed in order to recover ammonia, reduce organic matter content and upgrade biogas from digested pig slurry. A lab-scale dual-chamber MEC was equipped with a cation exchange membrane (CEM) and ARS with a hydrophobic membrane in the catholyte recirculation loop, to promote ammonia migration and absorption in an acidic solution. On the other hand, an electromethanogenic biofilm was developed in the biocathode to promote the transformation of CO2 into methane. The average nitrogen transference through the CEM was of 0.36 gN m−2 h−1 with a removal efficiency of 31%, with the ARS-HM in the catholyte recirculation loop. The removal of ammonia from the cathode compartment helped to maintain a lower pH value for the electromethanogenic biomass (7.69 with the ARS-HM, against 8.88 without ARS-HM) and boosted methane production from 50 L m−3 d−1 to 73 L m−3 d−1. Results have shown that the integration of an electromethanogenic MEC with an ARS-HM allows for the concomitant recovery of energy and ammonia from high strength wastewater digestates.
Quasi-Z-Source Inverter-Based Photovoltaic Power System Modeling for Grid Stability Studies
Authors: Monjo Lluís , Sainz Luis , Mesas Juan José , Pedra Joaquín
Published: January 2021

Quasi-Z-source inverters (qZSIs) are becoming a powerful power conversion technology in photovoltaic (PV) power systems because they allow energy power conversion in a single stage operation. However, they can cause system resonances and reduce system damping, which may lead to instabilities. These stability problems are well known in grid-connected voltage source converter systems but not in quasi-Z-source inverter (qZSI)-based PV power systems. This paper contributes with Matlab/Simulink and PSCAD/EMTDC models of qZSI-based PV power systems to analyze transient interactions and stability problems. These models consider all power circuits and control blocks of qZSI-based PV power systems and can be used in sensitivity studies on the influence of system parameters on stability. PV power system stability is assessed from the proposed models. The causes of instabilities are analyzed from numerical simulations and possible solutions are proposed.
Experimental Feasibility Study of a Direct Contact Latent Heat Storage Using an Ester as a Bio-Based Storage Material
Authors: Hegner Lukas , Krimmel Stefan , Ravotti Rebecca , Festini Dominic , Worlitschek Jörg , Stamatiou Anastasia
Published: January 2021

Latent heat storage (LHS) represents a valuable technology for the integration of intermittent renewable energy sources in existing and future energy systems. Improvements in LHS can be sought by enhancing heat transfer efficiency, compactness and diminishing the environmental impact of storage systems. In this paper, direct contact latent heat storage (DC-LHS) using esters as phase change material (PCM) is proposed as a promising compact storage technology to achieve high performance both in terms of heat transfer and sustainability. The technology allows for the heat transfer fluid (HTF) to flow directly through the PCM, forming a large amount of small droplets and thus providing a large heat exchange surface area between the two materials. At the same time, using biobased esters as PCM, gives the technology clear ecological advantages when compared to alternative types of compact energy storage. Furthermore, no complex heat transfer enhancing structures are necessary in a DC-LHS, further reducing the environmental impact and enabling very high energy densities. In this paper, the feasibility of this concept is explored for the first time by developing and testing an experimental DC-LHS device using methyl palmitate as PCM and water as HTF. The thermal performance and stability of the material combination are analysed by different melting–solidification experiments and distinctive effects are identified and comprehensively discussed for the first time. The basic concept as well as the novel material combination are validated. The study finds the critical challenges that must be overcome in order for this highly promising technology to be successfully implemented.
Modelling Bidding Behaviour on German Photovoltaic Auctions
Authors: Kácsor Enikő
Published: January 2021

In this article renewable energy support allocation through different types of auctions are assessed. The applied methodological framework is auction theory, based on the rules governing the German photovoltaic (PV) Feed-in Premium (FIP) auctions. The work focuses on bidding strategies based on an extended levelised cost of electricity (LCOE) methodology, comparing two different set of rules: uniform price and pay-as-bid. When calculating the optimal bids an iteration is developed to find the Nash-equilibrium optimal bidding strategy. When searching for the bid function, not only strictly monotone functions, but also monotone functions are considered, extending the framework typically applied in auction theory modelling. The results suggest that the PV support allocation in the German auction system would be more cost efficient using the uniform pricing rule, since many participants bid above their true valuation in the pay-as-bid auction Nash-equilibrium. Thus from a cost minimising perspective, the application of uniform pricing rule would be a better policy decision.
Some Observations on Shape Factors Influencing Aerodynamic Lift on Passenger Cars
Authors: Howell Jeff , Windsor Steve , Passmore Martin
Published: January 2021

The car aerodynamicist developing passenger cars is primarily interested in reducing aerodynamic drag. Considerably less attention is paid to the lift characteristics except in the case of high-performance cars. Lift, however, can have an effect on both performance and stability, even at moderate speeds. In this paper, the basic shape features which affect lift and the lift distribution, as determined from the axle loads, are examined from wind tunnel tests on various small-scale bodies representing passenger cars. In most cases, the effects of yaw are also considered. The front-end shape is found to have very little effect on overall lift, although it can influence the lift distribution. The shape of the rear end of the car, however, is shown to be highly influential on the lift. The add-on components and other features can have a significant effect on the lift characteristics of real passenger cars and are briefly discussed. The increase in lift at yaw is, surprisingly, almost independent of shape, as shown for the simple bodies. This characteristic is less pronounced on real passenger cars but lift increase at yaw is shown to rise with vehicle length.
COVID-19 Anxiety—A Longitudinal Survey Study of Psychological and Situational Risks among Finnish Workers
Authors: Savolainen Iina , Oksa Reetta , Savela Nina , Celuch Magdalena , Oksanen Atte
Published: January 2021

Background: The COVID-19 crisis has changed the conditions of many all over the globe. One negative consequence of the ongoing pandemic is anxiety brought about by uncertainty and the COVID-19 disease. Increased anxiety is a potential risk factor for wellbeing at work. This study investigated psychological, situational, and socio-demographic predictors of COVID-19 anxiety using longitudinal data. Methods: A nationally representative sample of Finnish workers (N = 1308) was collected before and during the COVID-19 crisis. Eighty percent of the participants responded to the follow-up study (N = 1044). COVID-19 anxiety was measured with a modified Spielberger State–Trait Anxiety Inventory. Psychological and situational predictors included perceived loneliness, psychological distress, technostress, personality, social support received from the work community, and remote working. A number of socio-demographic factors were also investigated. Results: Perceived loneliness, psychological distress, technostress, and neuroticism were identified as robust psychological predictors of COVID-19 anxiety. Increase in psychological distress and technostress during the COVID-19 crisis predicted higher COVID-19 anxiety. A recent change in their field of work and decreased social support from work communities predicted COVID-19 anxiety. Women and young people experienced higher anxiety. Conclusions: Different factors explain workers’ COVID-19 anxiety. Increased anxiety can disrupt wellbeing at work, emphasizing the organizations’ role in maintaining an inclusive and caring work culture and providing technical and psychological support to workers during crisis.