bluuebunny/crossref_metadata_2025 huggingface dataset:
Generating Functions for New Families of Combinatorial Numbers and Polynomials: Approach to Poisson–Charlier Polynomials and Probability Distribution Function
Authors: Kucukoglu Irem , Simsek Burcin , Simsek Yilmaz
Published: October 2019

The aim of this paper is to construct generating functions for new families of combinatorial numbers and polynomials. By using these generating functions with their functional and differential equations, we not only investigate properties of these new families, but also derive many new identities, relations, derivative formulas, and combinatorial sums with the inclusion of binomials coefficients, falling factorial, the Stirling numbers, the Bell polynomials (i.e., exponential polynomials), the Poisson–Charlier polynomials, combinatorial numbers and polynomials, the Bersntein basis functions, and the probability distribution functions. Furthermore, by applying the p-adic integrals and Riemann integral, we obtain some combinatorial sums including the binomial coefficients, falling factorial, the Bernoulli numbers, the Euler numbers, the Stirling numbers, the Bell polynomials (i.e., exponential polynomials), and the Cauchy numbers (or the Bernoulli numbers of the second kind). Finally, we give some remarks and observations on our results related to some probability distributions such as the binomial distribution and the Poisson distribution.
Bioprinting for Liver Transplantation
Authors: Kryou Christina , Leva Valentina , Chatzipetrou Marianneza , Zergioti Ioanna
Published: October 2019

Bioprinting techniques can be used for the in vitro fabrication of functional complex bio-structures. Thus, extensive research is being carried on the use of various techniques for the development of 3D cellular structures. This article focuses on direct writing techniques commonly used for the fabrication of cell structures. Three different types of bioprinting techniques are depicted: Laser-based bioprinting, ink-jet bioprinting and extrusion bioprinting. Further on, a special reference is made to the use of the bioprinting techniques for the fabrication of 2D and 3D liver model structures and liver on chip platforms. The field of liver tissue engineering has been rapidly developed, and a wide range of materials can be used for building novel functional liver structures. The focus on liver is due to its importance as one of the most critical organs on which to test new pharmaceuticals, as it is involved in many metabolic and detoxification processes, and the toxicity of the liver is often the cause of drug rejection.
Histone H2A and Bovine Neutrophil Extracellular Traps Induce Damage of Besnoitia besnoiti-Infected Host Endothelial Cells but Fail to Affect Total Parasite Proliferation
Authors: Conejeros Iván , Velásquez Zahady D. , Grob Daniela , Zhou Ershun , Salecker Hannah , Hermosilla Carlos , Taubert Anja
Published: October 2019

Besnoitia besnoiti tachyzoites infect and develop in bovine endothelial cells in vivo and trigger the release of neutrophil extracellular traps (NETs) from bovine polymorphonuclear neutrophils (PMN). The purpose of this study was to analyze if pure B. besnoiti tachyzoite-triggered NETs would damage endothelial host cells and subsequently influence intracellular development and proliferation of B. besnoiti tachyzoites in primary bovine endothelial cells. For comparison purposes, isolated A23187-induced NETs were also used. Thus, we here evaluated endothelial host cell damage triggered by histone 2A (H2A) and B. besnoiti tachyzoite-induced NET preparations and furthermore estimated the effects of PMN floating over B. besnoiti-infected endothelium under physiological flow conditions on endothelial host cell viability. Overall, all treatments (H2A, B. besnoiti-triggered NETs and floating PMN) induced endothelial cell death of B. besnoiti-infected host cells. However, though host cell damage led to significantly altered intracellular parasite development with respect to parasitophorous vacuole diameter and numbers, the total proliferation of the parasite over time was not significantly affected by these treatments thereby denying any direct effect of NETs on intracellular B. besnoiti replication.
IGF2BP1 Significantly Enhances Translation Efficiency of Duck Hepatitis A Virus Type 1 without Affecting Viral Replication
Authors: Chen Junhao , Zhang Ruihua , Lan Jingjing , Lin Shaoli , Li Pengfei , Gao Jiming , Wang Yu , Xie Zhi-Jing , Li Fu-Chang , Jiang Shi-Jin
Published: October 2019

As a disease characterized by severe liver necrosis and hemorrhage, duck viral hepatitis (DVH) is mainly caused by duck hepatitis A virus (DHAV). The positive-strand RNA genome of DHAV type 1 (DHAV-1) contains an internal ribosome entry site (IRES) element within the 5′ untranslated region (UTR), structured sequence elements within the 3′ UTR, and a poly(A) tail at the 3′ terminus. In this study, we first examined that insulin-like growth factor-2 mRNA-binding protein-1 (IGF2BP1) specifically interacted with the DHAV-1 3′ UTR by RNA pull-down assay. The interaction between IGF2BP1 and DHAV-1 3′ UTR strongly enhanced IRES-mediated translation efficiency but failed to regulate DHAV-1 replication in a duck embryo epithelial (DEE) cell line. The viral propagation of DHAV-1 strongly enhanced IGF2BP1 expression level, and viral protein accumulation was identified as the key point to this increment. Collectively, our data demonstrated the positive role of IGF2BP1 in DHAV-1 viral proteins translation and provided data support for the replication mechanism of DHAV-1.
Gossypol Suppresses Growth of Temozolomide-Resistant Glioblastoma Tumor Spheres
Authors: Kim Hee Yeon , Lee Byung Il , Jeon Ji Hoon , Kim Dong Keon , Kang Seok-Gu , Shim Jin-Kyoung , Kim Soo Youl , Kang Sang Won , Jang Hyonchol
Published: October 2019

Temozolomide is the current first-line treatment for glioblastoma patients but, because many patients are resistant to it, there is an urgent need to develop antitumor agents to treat temozolomide-resistant glioblastoma. Gossypol, a natural polyphenolic compound, has been studied as a monotherapy or combination therapy for the treatment of glioblastoma. The combination of gossypol and temozolomide has been shown to inhibit glioblastoma, but it is not clear yet whether gossypol alone can suppress temozolomide-resistant glioblastoma. We find that gossypol suppresses the growth of temozolomide-resistant glioblastoma cells in both tumor sphere and adherent culture conditions, with tumor spheres showing the greatest sensitivity. Molecular docking and binding energy calculations show that gossypol has a similar affinity to the Bcl2 (B-cell lymphoma 2) family of proteins and several dehydrogenases. Gossypol reduces mitochondrial membrane potential and cellular ATP levels before cell death, which suggests that gossypol inhibits several dehydrogenases in the cell’s metabolic pathway. Treatment with a Bcl2 inhibitor does not fully explain the effect of gossypol on glioblastoma. Overall, this study demonstrates that gossypol can suppress temozolomide-resistant glioblastoma and will be helpful for the refinement of gossypol treatments by elucidating some of the molecular mechanisms of gossypol in glioblastoma.
Flumequine-Mediated Upregulation of p38 MAPK and JNK Results in Melanogenesis in B16F10 Cells and Zebrafish Larvae
Authors: Karunarathne Wisurumuni Arachchilage Hasitha Maduranga , Molagoda Ilandarage Menu Neelaka , Kim Myung Sook , Choi Yung Hyun , Oren Matan , Park Eui Kyun , Kim Gi-Young
Published: October 2019

Flumequine is a well-known second generation quinolone antibiotic that induces phototoxicity. However, the effect of flumequine on skin melanogenesis is unclear. Therefore, we, for the first time, investigated whether flumequine regulates melanogenesis. The present study showed that flumequine slightly inhibited in vitro mushroom tyrosinase activity but significantly increased extracellular and intracellular melanin content in B16F10 cells and promoted the expression of microphthalmia-associated transcription factor (MITF) and tyrosinase. Additionally, flumequine remarkably increased melanin pigmentation in zebrafish larvae without any toxicity. We also found that flumequine stimulated p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) phosphorylation; inhibition of p38 MAPK and JNK resulted in significant downregulation of extracellular and intracellular melanin content in B16F10 cells and pigmentation of zebrafish larvae accompanied with suppression of MITF and tyrosinase expression, indicating that flumequine-mediated p38 and JNK promote melanogenesis in vitro and in vivo. According to the molecular docking prediction, flumequine targeted dual-specificity MAPK phosphatase 16 (DUSP16), which is a major negative regulator of p38 MAPK and JNK. Our findings demonstrate that flumequine induces an increase in melanin content in B16F10 cells and zebrafish larvae by activating p38 MAPK and JNK. These data show the potential of flumequine for use as an anti-vitiligo agent.
Modulating Linker Composition of Haptens Resulted in Improved Immunoassay for Histamine
Authors: Luo Lin , Wei Xiao-Qun , Jia Bao-Zhu , Yang Jin-Yi , Shen Yu-Dong , Hammock Bruce , Dong Jie-Xian , Wang Hong , Lei Hong-Tao , Xu Zhen-Lin
Published: October 2019

Histamine (HA) is an important food contaminant generated during food fermentation or spoilage. However, an immunoassay for direct (derivatization free) determination of HA has rarely been reported due to its small size to induce the desired antibodies by its current hapten-protein conjugates. In this work, despite violating the classical hapten design criteria which recommend introducing a linear aliphatic (phenyl free) linker into the immunizing hapten, a novel haptens, HA-245 designed and synthesized with a phenyl-contained linker, exhibited significantly enhanced immunological properties. Thus, a quality-improved monoclonal antibody (Mab) against HA was elicited by its hapten-carrier conjugates. Then, as the linear aliphatic linker contained haptens, Hapten B was used as linker-heterologous coating haptens to eliminate the recognition of linker antibodies. Indirect competitive ELISA (ic-ELISA) was developed with a 50% inhibition concentration (IC50) of 0.21 mg/L and a limit of detection (LOD) of 0.06 mg/L in buffer solution. The average recoveries of HA from spiked food samples for this ic-ELISA ranged from 84.1% and 108.5%, and the analysis results agreed well with those of referenced LC-MS/MS. This investigation not only realized derivatization-free immunoassay for HA, but also provided a valuable guidance for hapten design and development of immunoassay for small molecules.
Temporin-SHa and Its Analogs as Potential Candidates for the Treatment of Helicobacter pylori
Authors: Olleik Hamza , Baydoun Elias , Perrier Josette , Hijazi Akram , Raymond Josette , Manzoni Marine , Dupuis Lucas , Pauleau Ghislain , Goudard Yvain , de La Villéon Bruno , Goin Géraldine , Sockeel Philippe , Iqbal Choudhary Muhammad , Di Pasquale Eric , Nadeem-ul-Haque Muhammad , Ali Hunain , Iftikhar Khan Arif , Shaheen Farzana , Maresca Marc
Published: October 2019

Helicobacterpylori is one of the most prevalent pathogens colonizing 50% of the world’s population and causing gastritis and gastric cancer. Even with triple and quadruple antibiotic therapies, H. pylori shows increased prevalence of resistance to conventional antibiotics and treatment failure. Due to their pore-forming activity, antimicrobial peptides (AMP) are considered as a good alternative to conventional antibiotics, particularly in the case of resistant bacteria. In this study, temporin-SHa (a frog AMP) and its analogs obtained by Gly to Ala substitutions were tested against H. pylori. Results showed differences in the antibacterial activity and toxicity of the peptides in relation to the number and position of D-Ala substitution. Temporin-SHa and its analog NST1 were identified as the best molecules, both peptides being active on clinical resistant strains, killing 90–100% of bacteria in less than 1 h and showing low to no toxicity against human gastric cells and tissue. Importantly, the presence of gastric mucins did not prevent the antibacterial effect of temporin-SHa and NST1, NST1 being in addition resistant to pepsin. Taken together, our results demonstrated that temporin-SHa and its analog NST1 could be considered as potential candidates to treat H. pylori, particularly in the case of resistant strains.
A Landauer Formula for Bioelectronic Applications
Authors: Papp Eszter , Jelenfi Dávid P. , Veszeli Máté T. , Vattay Gábor
Published: October 2019

Recent electronic transport experiments using metallic contacts attached to proteins identified some “stylized facts”, which contradict conventional wisdom that increasing either the spatial distance between the electrodes or the temperature suppresses conductance exponentially. These include nearly temperature-independent conductance over the protein in the 30 to 300 K range, distance-independent conductance within a single protein in the 1 to 10 nm range and an anomalously large conductance in the 0.1 to 10 nS range. In this paper, we develop a generalization of the low temperature Landauer formula, which can account for the joint effects of tunneling and decoherence and can explain these new experimental findings. We use novel approximations, which greatly simplify the mathematical treatment and allow us to calculate the conductance in terms of a handful macroscopic parameters, instead of the myriads of microscopic parameters describing the details of an atomic level quantum chemical computation. The new approach makes it possible to get predictions for the outcomes of new experiments without relying solely on high performance computing and can distinguish important and unimportant details of the protein structures from the point of view of transport properties.
Transcriptional Modulation of the Host Immunity Mediated by Cytokines and Transcriptional Factors in Plasmodium falciparum-Infected Patients of North-East India
Authors: Ahmed Md Zohaib , Bhardwaj Nitin , Sharma Supriya , Pande Veena , Anvikar Anupkumar R
Published: October 2019

Complications due to malaria are caused mostly by host immunological responses. Plasmodium falciparum subverts host immunity by various strategies, including modulation in the host immune responses by regulating cytokines. The transcriptional alterations of major cytokines and immunoregulators were analyzed in this study through gene expression profiling in clinically defined subgroups of P. falciparum patients. Malaria patients were included from Dhalai district hospital of Tripura with uncomplicated malaria (UC) and severe malaria (SM) and healthy controls from endemic and non-endemic areas of India. qPCR gene expression analysis was performed for all factors and they were grouped into three clusters based on their altered expressions. The first cluster was downregulated with an increased parasitic burden which included T-BET, GATA3, EOMES, TGF-β, STAT4, STAT6 and cytokines IFN-γ, IL-12, IL-4, IL-5, and IL-13. RANTES, IL-8, CCR8, and CXCR3 were decreased in the SM group. The second cluster was upregulated with severity and included TNF-α, IL-10, IL-1β and IL-7. PD-1 and BCL6 were increased in the SM group. The third cluster comprised of NF-κB and was not altered. The level of perforin was suppressed while GrB expression was elevated in SM. P. falciparum malaria burden is characterized by the modulation of host immunity via compromization of T cell-mediated responses and suppression of innate immune-regulators.
Allopurinol Prevents the Lipogenic Response Induced by an Acute Oral Fructose Challenge in Short-Term Fructose Fed Rats
Authors: García-Arroyo Fernando E. , Monroy-Sánchez Fabiola , Muñoz-Jiménez Itzel , Gonzaga Guillermo , Andrés-Hernando Ana , Zazueta Cecilia , Juárez-Rojas J. Gabriel , Lanaspa Miguel A. , Johnson Richard J. , Sánchez-Lozada L. Gabriela
Published: October 2019

We investigated whether short term high fructose intake may induce early hepatic dysfunction in rats and to test whether allopurinol treatment may have beneficial effects. Twenty male Sprague-Dawley rats received 20% fructose in drinking water (10 treated with allopurinol and 10 received vehicle) and 10 control rats received tap water. After 14 days, the hepatic response to an acute fructose load was evaluated, and in fasted animals, respirometry studies in freshly isolated mitochondria were performed. In fasting rats, we did not find differences in systemic or hepatic uric acid and triglyceride concentrations among the groups, but mitochondrial respiratory control rate was significantly decreased by high fructose feeding and correlated with a reduced expression of Complex I, as well as decreased aconitase-2 activity. On the other hand, in fructose fed rats, an acute fructose load increased systemic and hepatic uric acid, triglycerides and oxidative stress. Fructose feeding was also associated with fructokinase and xanthine oxidase overexpression and increased liver de novo lipogenesis program (fatty acid synthase (FAS) and cell death-inducing DFFA-like effector C (CIDEC) overexpression, ATP citrate lyase (ACL) and acetyl coA carboxylase (ACC) overactivity and decreased AMP-activated protein kinase (AMPk) and endothelial nitric oxide synthase (eNOS) activation). Allopurinol treatment prevented hepatic and systemic alterations. These data suggest that early treatment with xanthine oxidase inhibitors might provide a therapeutic advantage by delaying or even halting the progression of non-alcoholic fatty liver disease (NAFLD).
FRET Microscopy in Yeast
Authors: Skruzny Michal , Pohl Emma , Abella Marc
Published: October 2019

Förster resonance energy transfer (FRET) microscopy is a powerful fluorescence microscopy method to study the nanoscale organization of multiprotein assemblies in vivo. Moreover, many biochemical and biophysical processes can be followed by employing sophisticated FRET biosensors directly in living cells. Here, we summarize existing FRET experiments and biosensors applied in yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe, two important models of fundamental biomedical research and efficient platforms for analyses of bioactive molecules. We aim to provide a practical guide on suitable FRET techniques, fluorescent proteins, and experimental setups available for successful FRET experiments in yeasts.
A Qualitative Study on the Impact of First Steps—A Peer-led Educational Intervention for People Newly Diagnosed with Parkinson’s Disease
Authors: Soundy Andrew , Collett Johnny , Lawrie Sophie , Coe Shelly , Roberts Helen , Hu Michele , Bromley Sally , Harling Peter , Reed Alex , Coeberg Jan , Carroll Camille , Dawes Helen
Published: October 2019

Aim: The dual aim of this research was to consider the impact of providing the First Steps program on the stories of people with Parkinson’s Disease (PD) and to investigate the psychosocial and emotional mechanisms which may explain this impact. Methods: A qualitative study using a subtle realist paradigm and hermeneutic phenomenological methodology was undertaken. A single semi-structured interview was used to consider the impact and experiences of people with PD who completed either the intervention (2-day peer-led behavior intervention using storytelling 6–8 weeks apart) or received telephone support calls as part of the active control group. Descriptive statistics and a narrative analysis were undertaken on the results. Results: Forty-two participants were invited to participate, forty of whom completed the interview. This included 18 from the intervention group and 22 from the active control group. The intervention group identified the value of the program as worth-while, demonstrating improved exercise behavior and coping mechanisms following the intervention. Three major stories (the affirmed, the validated and the transformed story) identified the impact of the intervention. Three internal mechanisms (perceived control, hope and action, and the individual’s mind set) alongside three social mechanisms (social comparison, social control and the first opportunity to share with peers) appeared to explain this impact. Conclusion: This study provides exciting and novel evidence of the impact of a peer-led psycho-educational intervention for people newly diagnosed with PD. Further research is needed to consider the impact of stories-based approaches on participants and consider a critical evaluation of the mechanisms which may explain changes in stories and self-reported behaviour.
Mesenchymal Cells Support the Oncogenicity and Therapeutic Response of the Hedgehog Pathway in Triple-Negative Breast Cancer
Authors: Reyes-Ramos Ana M. , Ramos-Cruz Karla P. , Rodríguez-Merced Nelson J. , Martínez-Montemayor Michelle M. , Franqui-Ríos Nelson D. , Ríos-Grant Jan P. , Flores Andrea , Maldonado-Martínez Gerónimo , Torres-García Wandaliz , Domenech Maribella
Published: October 2019

The paracrine interaction between tumor cells and adjacent stroma has been associated with the oncogenic activity of the Hedgehog (Hh) pathway in triple-negative breast tumors. The present study developed a model of paracrine Hh signaling and examined the impact of mesenchymal cell sources and culture modalities in the oncogenicity of the Hh pathway in breast tumor cells. Studies consisted of tumor cell monocultures and co-cultures with cancer-associated and normal fibroblasts, tumor cells that undergo epithelial–mesenchymal transition (EMT), or adipose-derived mesenchymal stem cells (ADMSCs). Hh ligand and pathway inhibitors, GANT61 and NVP-LDE225 (NVP), were evaluated in both cell cultures and a mouse xenograft model. Results in monocultures show that tumor cell viability and Hh transcriptional activity were not affected by Hh inhibitors. In co-cultures, down-regulation of GLI1, SMO, and PTCH1 in the stroma correlated with reduced tumor growth rates in xenografted tumors and cell cultures, confirming a paracrine interaction. Fibroblasts and EMT cells supported Hh transcriptional activity and enhanced tumor cell growth. Mixed and adjacent culture modalities indicate that tumor growth is supported via fibroblast-secreted soluble factors, whereas enriched tumor stemness requires close proximity between tumor and fibroblasts. Overall this study provides a tumor–mesenchymal model of Hh signaling and highlights the therapeutic value of mesenchymal cells in the oncogenic activity of the Hh pathway.
LncRNAs as Chromatin Regulators in Cancer: From Molecular Function to Clinical Potential
Authors: Begolli Rodiola , Sideris Nikos , Giakountis Antonis
Published: October 2019

During the last decade, high-throughput sequencing efforts in the fields of transcriptomics and epigenomics have shed light on the noncoding part of the transcriptome and its potential role in human disease. Regulatory noncoding RNAs are broadly divided into short and long noncoding transcripts. The latter, also known as lncRNAs, are defined as transcripts longer than 200 nucleotides with low or no protein-coding potential. LncRNAs form a diverse group of transcripts that regulate vital cellular functions through interactions with proteins, chromatin, and even RNA itself. Notably, an important regulatory aspect of these RNA species is their association with the epigenetic machinery and the recruitment of its regulatory apparatus to specific loci, resulting in DNA methylation and/or post-translational modifications of histones. Such epigenetic modifications play a pivotal role in maintaining the active or inactive transcriptional state of chromatin and are crucial regulators of normal cellular development and tissue-specific gene expression. Evidently, aberrant expression of lncRNAs that interact with epigenetic modifiers can cause severe epigenetic disruption and is thus is closely associated with altered gene function, cellular dysregulation, and malignant transformation. Here, we survey the latest breakthroughs concerning the role of lncRNAs interacting with the epigenetic machinery in various forms of cancer.
Detailed Characterization of Immune Cell Infiltrate and Expression of Immune Checkpoint Molecules PD-L1/CTLA-4 and MMR Proteins in Testicular Germ Cell Tumors Disclose Novel Disease Biomarkers
Authors: Lobo João , Rodrigues Ângelo , Guimarães Rita , Cantante Mariana , Lopes Paula , Maurício Joaquina , Oliveira Jorge , Jerónimo Carmen , Henrique Rui
Published: October 2019

Background: The immune infiltrate plays an important part in testicular germ cell tumors, but it remains scarcely studied. We aimed at thoroughly characterizing the immune infiltrate and expression of immune checkpoints PD-L1/CTLA-4 and mismatch repair (MMR) proteins in these neoplasms, seeking for associations with patient outcome. Methods: A total of 162 consecutively diagnosed patients (2005–2018) were included. Immunostaining for PD-L1, CTLA-4 and MMR proteins was independently assessed both in immune cells (ICs) and tumor cells (TCs) of primary tumors and metastases, and characterization of IC populations was pursued. Results: PD-L1 and CTLA-4 positivity in ICs was frequent (85.5% and 96.3%). Patients with absent PD-L1 positive ICs exhibited significantly worse relapse-free survival (hazard ratio = 4.481, 95% CI 1.366–14.697, p = 0.013), both in univariable and multivariable analysis. Lower CD20 and CD3 IC infiltration in seminomas associated with higher disease stage (p = 0.0216, p = 0.0291). CTLA-4 TC intensity was significantly higher in yolk sac tumor, choriocarcinoma and teratoma, while PD-L1 TC positivity was significantly more frequent in choriocarcinoma. Both PD-L1 and CTLA-4 immunoexpression in ICs of metastatic samples was frequent (100% and 88.2%). MMR proteins were differentially expressed among the different tumor subtypes. Conclusions: Immune infiltrate/checkpoints associate with patients’ outcome, constituting novel (potentially targetable) disease biomarkers.
Preliminary Study on the Application of Concentrated Solar Power in Metallurgy of Titanium
Authors: Kováčik Jaroslav , Mináriková Natália , Dvorák Tomáš , Rodríguez Jose , Cañadas Inmaculada , Al-Athel Klaled Saleh , Šugár Peter , Šugárová Jana , Emmer Štefan
Published: October 2019

The applicability of concentrated solar power for metallurgy of titanium is discussed based on preliminary experimental works performed at Plataforma Solar de Almeria Spain, using solar furnace SF40 under protective argon atmosphere. As a starting material, titanium powder was used. The possibility of melting titanium compacts on yttria stabilized zirconia mat was investigated, and the effect of density and size of different green compacts was studied. It was observed that the time to achieve melting point is very short when concentrated solar power is used. The obtained results are expected to be similar for titanium sponge from which titanium powder is processed. After optimization of processing parameters, this will probably lead to a significant decrease of carbon footprint in the titanium ingots and castings production.
An Engineering Toolbox for the Evaluation of Metallic Flow Field Plates
Authors: Reimer Uwe , Froning Dieter , Nelissen Gert , Raymakers Leonard F. J. M. , Zhang Shidong , Beale Steven B. , Lehnert Werner
Published: October 2019

Metallic flow field plates, also called bipolar plates, are an important component of fuel cell stacks, electrolyzers, hydrogen purification and compression stacks. The manufacturing of these plates by means of stamping or hydroforming is highly suitable for mass production. In this work, a toolbox is created that is suitable for a screening process of different flow field design variants. For this purpose, the geometry and computational mesh are generated in an automated manner. Basic building blocks are combined using the open source software SALOME, and these allow for the construction of a large variant of serpentine-like flow field structures. These geometric variants are evaluated through computational fluid dynamics (CFD) simulations with the open source software OpenFOAM. The overall procedure allows for the screening of more than 100 variants within one week using a standard desktop computer. The performance of the flow fields is evaluated on the basis of two parameters: the overall pressure difference across the plate and the relative difference of the hydrogen concentration at the outlet of the channels. The results of such a screening first provide information about optimum channel geometry and the best choice of the general flow field layout. Such results are important at the beginning of the design process, as the channel geometry has an influence on the selection of the metal for deep drawing or hydroforming processes.
Making Meaningful Improvements in Pharmacotherapy and Medication Management for Children and Youth—A Modest Proposal
Authors: Parrish II Richard H. , van den Anker Johannes , Benavides Sandra
Published: October 2019

The Special Issue, “Development of a National Pediatric Pharmacotherapy Collaborative Practice Network,” has illuminated the vital global need for better care coordination and interprofessional collaboration in pharmacotherapy and medication management of children with medical complexity and special healthcare needs (CSHCN-CMC) [...]
Plasma Treatments to Improve the Bonding of Thermo-Treated Cherry Wood
Authors: Zheng Qingzhu , Zhang Weifeng , Lin Huiping , Yu Junwen , Yang Wenbin , Zhang Xinxiang
Published: October 2019

Thermal treatment can significantly improve the dimensional stability of wood, but it will decrease the bonding strength. In this work, the bonding strength of thermo-treated cherry wood boards was improved by plasma treatment. The change of wettability, surface morphology, and surface chemical property of cherry wood before and after plasma treatment was investigated by water contact angle measurement, Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). The plasma treatment significantly improved the wettability of thermo-treated cherry wood by decreasing its water contact angle from 109.95° to 53.18°. N2 or O2 was used as the plasma atmosphere, and it was found that N2 plasma treatment afforded cherry wood a rougher surface. The AFM roughness of cherry wood was increased from 19 nm to 31.9 nm after N2 plasma treatment. XPS results revealed an additional C–N group for N2 plasma treatment and the content of C=O, O–C–O, and O–C=O increased for O2 plasma treatment, respectively, indicating that the surface chemical property of cherry wood was modified. Due to the surface character, the bonding strength increased by 21.17% for N2 plasma treatment and 15.32% for O2 plasma treatment.
Anion Influence on the Packing of 1,3-Bis(4-Ethynyl-3-Iodopyridinium)-Benzene Halogen Bond Receptors
Authors: Decato Daniel A. , Riel Asia Marie S. , Berryman Orion B.
Published: October 2019

Rigid and directional arylethynyl scaffolds have been widely successful across diverse areas of chemistry. Utilizing this platform, we present three new structures of a dicationic 1,3-bis(4-ethynyl-3-iodopyridinium)-benzene halogen bonding receptor with tetrafluoroborate, nitrate, and hydrogen sulfate. Structural analysis focused on the receptor conformation, anion shape, solvation, and long range packing of these systems. Coupled with our previously reported structures, we concluded that anions can be classified as building units within this family of halogen bonding receptors. Two kinds of antiparallel dimers were observed for these dicationic receptors. An off-centered species was most frequent, present among geometrically diverse anions and assorted receptor conformations. In contrast, the centered antiparallel dimers were observed with receptors adopting a bidentate conformation in the solid-state. While anions support the solid-state formation of dimers, the molecular geometry and characteristics (planarity, rigidity, and directionality) of arylethynyl systems increase the likelihood of dimer formation by limiting efficient packing arrangements. The significantly larger cation may have considerable influence on the solid-state packing, as similar cationic arylethynyl systems also display these dimers.
Combination of Active Learning and Semi-Supervised Learning under a Self-Training Scheme
Authors: Fazakis Nikos , Kanas Vasileios G. , Aridas Christos K. , Karlos Stamatis , Kotsiantis Sotiris
Published: October 2019

One of the major aspects affecting the performance of the classification algorithms is the amount of labeled data which is available during the training phase. It is widely accepted that the labeling procedure of vast amounts of data is both expensive and time-consuming since it requires the employment of human expertise. For a wide variety of scientific fields, unlabeled examples are easy to collect but hard to handle in a useful manner, thus improving the contained information for a subject dataset. In this context, a variety of learning methods have been studied in the literature aiming to efficiently utilize the vast amounts of unlabeled data during the learning process. The most common approaches tackle problems of this kind by individually applying active learning or semi-supervised learning methods. In this work, a combination of active learning and semi-supervised learning methods is proposed, under a common self-training scheme, in order to efficiently utilize the available unlabeled data. The effective and robust metrics of the entropy and the distribution of probabilities of the unlabeled set, to select the most sufficient unlabeled examples for the augmentation of the initial labeled set, are used. The superiority of the proposed scheme is validated by comparing it against the base approaches of supervised, semi-supervised, and active learning in the wide range of fifty-five benchmark datasets.
Causal Composition: Structural Differences among Dynamically Equivalent Systems
Authors: Albantakis Larissa , Tononi Giulio
Published: October 2019

The dynamical evolution of a system of interacting elements can be predicted in terms of its elementary constituents and their interactions, or in terms of the system’s global state transitions. For this reason, systems with equivalent global dynamics are often taken to be equivalent for all relevant purposes. Nevertheless, such systems may still vary in their causal composition—the way mechanisms within the system specify causes and effects over different subsets of system elements. We demonstrate this point based on a set of small discrete dynamical systems with reversible dynamics that cycle through all their possible states. Our analysis elucidates the role of composition within the formal framework of integrated information theory. We show that the global dynamical and information-theoretic capacities of reversible systems can be maximal even though they may differ, quantitatively and qualitatively, in the information that their various subsets specify about each other (intrinsic information). This can be the case even for a system and its time-reversed equivalent. Due to differences in their causal composition, two systems with equivalent global dynamics may still differ in their capacity for autonomy, agency, and phenomenology.
A Class of Association Measures for Categorical Variables Based on Weighted Minkowski Distance
Authors: Zhang Qingyang
Published: October 2019

Measuring and testing association between categorical variables is one of the long-standing problems in multivariate statistics. In this paper, I define a broad class of association measures for categorical variables based on weighted Minkowski distance. The proposed framework subsumes some important measures including Cramér’s V, distance covariance, total variation distance and a slightly modified mean variance index. In addition, I establish the strong consistency of the defined measures for testing independence in two-way contingency tables, and derive the scaled forms of unweighted measures.
A Reconfigurable Radio-Frequency Converter IC in 0.18 µm CMOS
Authors: Sánchez-Azqueta Carlos , Guerrero Erick , Gimeno Cecilia , Celma Santiago
Published: October 2019

This work presents a reconfigurable RF converter for DVB-T television applications using triple-play over GPON. The system takes the DVB-T input, a wavelength division multiplexing (WDM) signal with spectral inversion in the range from 47 M Hz –1000 M Hz , up-converts its frequency to the band-pass of a highly selective surface-acoustic wave (SAW) filter centered at 1.3 G Hz , and then down-converts it so that it is compatible with the antenna input of conventional television sets. The designed RF converter incorporates two pairs of frequency synthesizer and mixer, based, respectively, on an integer-N phase-locked loop (PLL) with two LC-tank VCOs with 128 coarse tuning bands in the range from 1.35 G Hz –2.7 G Hz , and a double-balanced Gilbert cell, modified for better impedance matching and improved linearity. It is fed with regulated supplies compensated in temperature and programmed by an I 2 C interface operating on five 16-bit registers. This work presents the experimental characterization of the whole system plus selected cells for stand-alone testing, which have been fabricated in a 0.18 m CMOS process.
A High-Resolution Measurement System Designed for Semiconductor Microcalorimetry Sensors
Authors: Malcher Andrzej , Bernacki Krzysztof , Skupin Piotr , Choiński Dariusz
Published: October 2019

The quality of measurements of non-electrical quantities not only depends on the sensor but also on the electronic system that is used for the conversion of the electrical signals to a digital form. Many research papers on the subject analyse the properties and characteristics of the sensors in detail but omit the properties of the instruments that are used to measure the characteristics. This paper concentrates on the problems concerning the design of an instrument for generating control signals and measuring the output signals of a semiconductor sensor. The measurement instrument is designed for a commercial heat flow microcalorimeter that is able to measure heat flows at the level of several µW. The novelty of this paper is the analysis of some of the undocumented properties of the sensor and the interactions between its components. The design of the instrument makes it possible to correctly measure the output signals of a microcalorimeter without the influence of the described effects. The added value of this paper is a detailed analysis of the resolution of the system and the factors that may affect it. The remarks contained in the paper can be useful for designers of other instruments that are designed for measuring non-electrical quantities.
A High Channel Consistency Subarray of Plane-Wave Generators for 5G Base Station OTA Testing
Authors: Qiao Zhaolong , Wang Zhengpeng , Miao Jungang
Published: October 2019

A high channel consistency subarray of plane-wave generators (PWG) is described for fifth-generation (5G) base station (BS) over-the-air (OTA) testing. Firstly, the variation of the near field radiation characteristics of the subarray based on the feed amplitude and phase errors of the traditional power divider network is analyzed. The recommended amplitude and phase errors between channels are given. After that, a novel subarray which combines four pyramidal horn antennas and a compact 1:4 waveguide power divider is designed. The optimized perfectly symmetrical zigzag waveguide transmission lines are used to realize consistent power allocation among antenna elements. No intermediate pins are employed, which avoids the significant deterioration of channel consistency caused by assembly errors. The size of the subarray is 4.89 λ0 × 4.97 λ0 × 1.23 λ0 (λ0 is the working wavelength corresponding to the subarray center frequency at 3.5 GHz). The VSWR < 1.5 impedance bandwidth covers 3.4 GHz to 3.6 GHz. The amplitude difference between the four elements of the subarray is less than 0.5 dB, and the phase difference is less than 3°. The simulated and measured results agree well in this design.
Platform-Based Business Models: Insights from an Emerging AI-Enabled Smart Building Ecosystem
Authors: Xu Yueqiang , Ahokangas Petri , Turunen Marja , Mäntymäki Matti , Heikkilä Jukka
Published: October 2019

Artificial intelligence (AI) is emerging to become a highly potential enabling technology for smart buildings. However, the development of AI applications quite often follows a traditional, closed, and product-oriented approach. This study aims to introduce the platform model and ecosystem thinking to the development of AI-enabled smart buildings. The study identifies the needs for a user-oriented digital service ecosystem and business model in the smart building sector in Finland, which aimed to facilitate the launch of scalable businesses and an experiential and dynamic business ecosystem. A multi-method, interpretive case study was applied in the focal ecosystem, with the leading real estate and facility management operators in Northern Europe as part of a Finnish national innovation project. Our results propose an extended comprehensive framework of the 5C ecosystemic model (Connection, Content, Computation, Context, and Commerce) and the possible paths of ecosystem players in the domain of smart building and smart built environment, both theoretically and empirically. The platform-oriented business models are missing, yet desired, by the ecosystem actors. The value chain and ecosystem platforms imply the quest for new (platform) models. Finally, our research discusses the need for new value-chain- and ecosystem-oriented AI development and big data platforms in the future.
Effect of Channel Diameter on the Combustion and Thermal Behavior of a Hydrogen/Air Premixed Flame in a Swirl Micro-Combustor
Authors: Yang Xiao , He Zhihong , Zhao Lei , Dong Shikui , Tan Heping
Published: October 2019

Improving the flame stability and thermal behavior of the micro-combustor (MC) are major challenges in microscale combustion. In this paper, the micro combustions of an H2/air premixed flame in a swirl MC with various channel diameters (Din = 2, 3, 4 mm) were analyzed based on an established three-dimensional numerical model. The effects of hydrogen mass flow rate, thermal conductivity of walls, and the preferential transport of species were investigated. The results indicated that the flame type was characterized by the presence of two recirculation zones. The flame was anchored by the recirculation zones, and the anchoring location of the flame root was the starting position of the recirculation zones. The recirculation zones had a larger distribution of local equivalence ratio, especially in the proximity of the flame root, indicating the formation of a radical pool. The combustion efficiency increased with an increasing Din due to the longer residence time of the reactants. Furthermore, the MC with Din = 2 mm obtained the highest outer wall temperature distribution. However, the MC with Din = 4 mm had a better uniformity of outer wall temperature and large emitter efficiency due to the larger radiation surface. An increase in thermal conductivity boosts the thermal performance of combustion efficiency, emitter efficiency, and wall temperature uniformity. But there is a critical point of thermal conductivity that can increase the thermal performance. The above results can offer us significant guidance for designing MC with high thermal performance.
Radiation View Factor for Building Applications: Comparison of Computation Environments
Authors: Alam Marzia , Gul Mehreen Saleem , Muneer Tariq
Published: October 2019

Computation of view factors is required in several building engineering applications where radiative exchange takes place between surfaces such as ground and vertical walls or ground and sloping thermal or photovoltaics collectors. In this paper, view factor computations are performed for bifacial solar photovoltaic (PV) collectors based on the finite element method (FEM) using two programming languages known as Microsoft Excel-Visual Basic for Applications (VBA) and Python. The aim is to determine the computer response time as well as the performance of the two languages in terms of accuracy and convergence of the numerical solution. To run the simulations in Python, an open source just-in-time (JIT) compiler called Numba was used and the same program was also run as a macro in VBA. It was observed that the simulation response time significantly decreased in Python when compared to VBA. This decrease in time was due to the increase in the total number of iterations from 400 million to 250 billion for a given case. Results demonstrated that Python was 71–180 times faster than VBA and, therefore, offers a better programming platform for the view factor analysis and modelling of bifacial solar PV where computation time is a significant modelling challenge.
Cost-Optimal Plus Energy Building in a Cold Climate
Authors: Firląg Szymon
Published: October 2019

The main objective of this article is to propose possible requirements for cost-optimal plus energy building in a cold, heating dominated climate. The open question is what is more cost-effective: reduction of energy demand or increase of production from renewable energy sources. The target of the research was to check which solution has the lowest investment and maintenance costs. The analysis was made for a single-family house located in central Poland, including three different energy standards: WT2021 with energy need for heating ≤100 kWh/(m² year), NF40 with energy need for heating ≤40 kWh/(m² year) and NF15 with energy need for heating ≤15 kWh/(m² year)). Air and ground source heat pumps were used as a heat source and a photovoltaic system for the production of the electrical energy. For each case the investment and running costs were calculated very precisely, taking into account heating, ventilation, domestic hot water and auxiliary systems. Global cost for a 30-year period showed that house variants with air source heat pumps are more cost effective. The investment, replacement and maintenance cost related with energy systems have the biggest share in the global cost. Reaching the plus energy standard was possible only in the case of low-energy standard NF40 and NF15. Based on this research the proposed requirements for plus energy single-family residential buildings in central Poland are the following: the final (delivered) electrical energy demand (including heating, ventilation, domestic hot water and auxiliary systems) <45 kWh/(m² year) and the on-site electrical energy production >45 kWh/(m² year).