bluuebunny/crossref_metadata_2025 huggingface dataset:
Twisted Hermitian Codes
Authors: Allen Austin , Blackwell Keller , Fiol Olivia , Kshirsagar Rutuja , Matsick Bethany , Matthews Gretchen L. , Nelson Zoe
Published: December 2020

We define a family of codes called twisted Hermitian codes, which are based on Hermitian codes and inspired by the twisted Reed–Solomon codes described by Beelen, Puchinger, and Nielsen. We demonstrate that these new codes can have high-dimensional Schur squares, and we identify a subfamily of twisted Hermitian codes that achieves a Schur square dimension close to that of a random linear code. Twisted Hermitian codes allow one to work over smaller alphabets than those based on Reed–Solomon codes of similar lengths.
Facilitating Numerical Solutions of Inhomogeneous Continuous Time Markov Chains Using Ergodicity Bounds Obtained with Logarithmic Norm Method
Authors: Zeifman Alexander , Satin Yacov , Kovalev Ivan , Razumchik Rostislav , Korolev Victor
Published: December 2020

The problem considered is the computation of the (limiting) time-dependent performance characteristics of one-dimensional continuous-time Markov chains with discrete state space and time varying intensities. Numerical solution techniques can benefit from methods providing ergodicity bounds because the latter can indicate how to choose the position and the length of the “distant time interval” (in the periodic case) on which the solution has to be computed. They can also be helpful whenever the state space truncation is required. In this paper one such analytic method—the logarithmic norm method—is being reviewed. Its applicability is shown within the queueing theory context with three examples: the classical time-varying M/M/2 queue; the time-varying single-server Markovian system with bulk arrivals, queue skipping policy and catastrophes; and the time-varying Markovian bulk-arrival and bulk-service system with state-dependent control. In each case it is shown whether and how the bounds on the rate of convergence can be obtained. Numerical examples are provided.
A Valid Dynamical Control on the Reverse Osmosis System Using the CESTAC Method
Authors: Noeiaghdam Samad , Sidorov Denis , Zamyshlyaeva Alyona , Tynda Aleksandr , Dreglea Aliona
Published: December 2020

The aim of this study is to present a novel method to find the optimal solution of the reverse osmosis (RO) system. We apply the Sinc integration rule with single exponential (SE) and double exponential (DE) decays to find the approximate solution of the RO. Moreover, we introduce the stochastic arithmetic (SA), the CESTAC method (Controle et Estimation Stochastique des Arrondis de Calculs) and the CADNA (Control of Accuracy and Debugging for Numerical Applications) library instead of the mathematical methods based on the floating point arithmetic (FPA). Applying this technique, we would be able to find the optimal approximation, the optimal error and the optimal iteration of the method. The main theorems are proved to support the method analytically. Based on these theorems, we can apply a new stopping condition in the numerical procedure instead of the traditional absolute error. These theorems show that the number of common significant digits (NCSDs) of exact and approximate solutions are almost equal to the NCSDs of two successive approximations. The numerical results are obtained for both SE and DE Sinc integration rules based on the FPA and the SA. Moreover, the number of iterations for various ε are computed in the FPA. Clearly, the DE case is more accurate and faster than the SE for finding the optimal approximation, the optimal error and the optimal iteration of the RO system.
New Hydroquinone Monoterpenoid and Cembranoid-Related Metabolites from the Soft Coral Sarcophyton tenuispiculatum
Authors: Huang Tzu-Yin , Huang Chiung-Yao , Chen Shu-Rong , Weng Jing-Ru , Tu Tzu-Hsuan , Cheng Yuan-Bin , Wu Shih-Hsiung , Sheu Jyh-Horng
Published: December 2020

Chemical investigation of the marine soft coral Sarcophyton tenuispiculatum resulted in the isolation of a 1,4-dihydrobenzoquinone, sarcotenuhydroquinone (1), three new cembranoids, sarcotenusenes A‒C (2‒4), and ten previously reported metabolites 5–14. The chemical structures of all isolated metabolites were determined by detailed spectroscopic analyses. In biological assays, anti-inflammatory, cytotoxic, and peroxisome proliferator-activated receptor γ (PPAR-γ) transcription factor assays of all compounds were performed. None of the isolated compounds were found to exhibit activity in the PPAR-γ transcription factor assay. The anti-inflammatory assays showed that (+)-7α,8β-dihydroxydeepoxysarcophine (13) inhibited the production of IL-1β to 56 ± 1% at a concentration of 30 µM in lipopolysaccharide (LPS)-stimulated J774A.1 macrophage cells. In addition, 1 and 2 were found to exhibit cytotoxicity towards a panel of cancer cell lines.
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Organic Disease or Psychosomatic Illness? A Re-Examination of the Royal Free Epidemic of 1955
Authors: Underhill Rosemary , Baillod Rosemarie
Published: December 2020

Background and Objectives: Controversy exists over whether myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is an organic disease or a psychosomatic illness. ME/CFS usually occurs as sporadic cases, but epidemics (outbreaks) have occurred worldwide. Myalgic encephalomyelitis was named to describe an outbreak affecting the lymphatic, muscular, and nervous systems that closed the Royal Free hospital for three months in 1955. Fifteen years later, two psychiatrists concluded that epidemic hysteria was the likely cause. ME/CFS research studies show multiple pathophysiological differences between patients and controls and a possible etiological role for infectious organisms, but the belief that ME/CFS is psychosomatic is widespread and has been specifically supported by the epidemic hysteria hypothesis for the Royal Free outbreak. Our objective was to obtain accounts from ex-Royal Free hospital staff who personally experienced the 1955 outbreak and evaluate evidence for it being an infectious illness versus epidemic hysteria. Materials and Methods: Statements in the newsletters of two organizations for staff who had worked at the Royal Free hospital invited anyone who had experienced the 1955 Royal Free outbreak to contact the authors. Accounts of the outbreak from telephone interviews and letters were evaluated against the “epidemic hysteria hypothesis” paper and original medical staff reports. Results: Twenty-seven ex-Royal Free hospital staff, including six who had developed ME, provided descriptions typical of an infectious illness affecting the lymphatic, muscular, and nervous systems, and were not consistent with epidemic hysteria. Conclusions: The 1955 Royal Free hospital epidemic of myalgic encephalomyelitis was an organic infectious disease, not psychogenic epidemic hysteria.
Chronometric vs. Structural Hypercoagulability
Authors: Delianu Carmen , Moscalu Mihaela , Hurjui Loredana Liliana , Tărniceriu Claudia Cristina , Bădulescu Oana-Viola , Lozneanu Ludmila , Hurjui Ion , Goriuc Ancuta , Surlari Zinovia , Foia Liliana
Published: December 2020

Prolonged tourniquet stasis induced by venepuncture can lead to the release of the plasma of cell lysis products, as well as tissue factor (TF), impairing the quality of coagulation test results. The accidental presence of TF in vitro can trigger the coagulation mechanism, generating a false decrease in prothrombin time (PT). Background and Objectives: Identification of short PT tests below the normal reference value that could suggest a situation of hypercoagulability. The study aimed to compare the results of the shortened PT tests at their first determination with the eventual correction following duplication of the analysis from the same sample. Materials and methods: Identification of the shortened PT tests has been carried out for a period of 4 months, upon 544 coagulation samples referred to the Hematology department of Sf. Spiridon County Clinical Emergency Hospital from Iasi, Romania. Results: Out of the 544 samples of which the results indicated a state of hypercoagulability, by repeating the determination from the same sample, for 200 (36.76%) PT tests (p = 0.001) the value was corrected, falling within the normal reference range. For 344 (63.24%) tests, the results suggested a situation of hypercoagulability. Conclusions: In order to guarantee the highest quality of the laboratory services, a proper interpretation and report of the patients’ results must be congruent and harmoniously associated to the actual clinical condition of the patient. Duplication of the PT determination from the same sample would exclude situations of false hypercoagulability and would provide significant improvement for the patient’s safety.
High Expression of KLF10 Is Associated with Favorable Survival in Patients with Oral Squamous Cell Carcinoma
Authors: Yeh Chung-Min , Lee Yi-Ju , Ko Po-Yun , Lin Yueh-Min , Sung Wen-Wei
Published: December 2020

Background and Objectives: Krüppel-like transcription factor 10 (KLF10) plays a vital role in regulating cell proliferation, including the anti-proliferative process, activation of apoptosis, and differentiation control. KLF10 may also act as a protective factor against oral cancer. We studied the impact of KLF10 expression on the clinical outcomes of oral cancer patients to identify its role as a prognostic factor in oral cancer. Materials and Methods: KLF10 immunoreactivity was analyzed by immunohistochemical (IHC) stain analysis in 286 cancer specimens from primary oral cancer patients. The prognostic value of KLF10 on overall survival was determined by Kaplan–Meier analysis and the Cox proportional hazard model. Results: High KLF10 expression was significantly associated with male gender and betel quid chewing. The 5-year survival rate was greater for patients with high KLF10 expression than for those with low KLF10 expression (62.5% vs. 51.3%, respectively; p = 0.005), and multivariate analyses showed that high KLF10 expression was the only independent factor correlated with greater overall patient survival. The significant correlation between high KLF10 expression and a higher 5-year survival rate was observed in certain subgroups of clinical parameters, including female gender, non-smokers, cancer stage T1, and cancer stage N0. Conclusions: KLF10 expression, detected by IHC staining, could be an independent prognostic marker for oral cancer patients.
Chronic Intradiploic Organizing Hematoma of the Skull Mimicking Calvarial Tumor Diagnosed Using Zero TE MRI: A Case Report and Review of Literature
Authors: Park Hyun , Nam In Chul , Baek Hye Jin , Ryu Kyeong Hwa , Cho Eun , Kim Seung Soo , An Hyo Jung
Published: December 2020

Chronic intradiploic organizing hematoma of the skull is a rare lesion that usually presents as a progressively growing mass after head trauma, thus making it difficult to diagnose. To date, only nine cases that have been histopathologically confirmed as organizing hematoma of the skull have been reported in the literature. Herein, we describe a case of a chronic organizing hematoma involving the right parietal bone, presenting as a slowly growing mass in a 54-year-old man. The lesion was also visualized on magnetic resonance imaging (MRI) with a zero echo time sequence. In this case report, we emphasize that chronic intradiploic organizing hematoma should be considered in the differential diagnosis of a palpable scalp mass. We also highlight the importance of meticulous radiological review in the context of appropriate clinical suspicion and the usefulness of the zero TE sequence in evaluating calvarial lesions.
Characterizing the Soldering Alloy Type Zn–Al–Cu and Study of Ultrasonic Soldering of Al7075/Cu Combination
Authors: Kolenak Roman , Kostolny Igor , Drapala Jaromir , Babincova Paulina , Sahul Martin
Published: December 2020

The aim of the research was to characterize the soldering alloy type Zn–Al–Cu and study the fluxless ultrasonic soldering of the combination of aluminum alloy type Al7075 with copper substrate. The Zn–Al–Cu solder is of the close-to-eutectic type with two phase transformations: the eutectic transformation at 378 °C and the eutectoid transformation at 285 °C. The solder microstructure is formed of a matrix composed of the solid solutions of aluminum (Al) and zinc (Zn) in which the copper phases CuZn4 and CuAl2 are precipitated. The shear strength of the soldering alloy type Zn5Al with copper addition reaches values from 167 to 187 MPa and it depends on the copper content in the solder. The bond with aluminum alloy type Al7075 is formed due to the solubility of Al in zinc solder at the formation of solid solution Al. Contrary to this observation, the bond with the copper substrate is in this case formed due to the interaction of zinc and aluminum with the copper substrate. Two new intermetallic phases, namely Al(Cu,Zn)2 and Cu3.2Zn0.7Al4.2, were formed. The average shear strength of Al7075/Zn5Al3Cu/Cu joints attained was 134.5 MPa. For comparison, the Cu/Zn5Al3Cu/Cu joint attained an average shear strength of 136.5 MPa.
Development of a Novel High-Temperature Al Alloy for Laser Powder Bed Fusion
Authors: Belelli Filippo , Casati Riccardo , Riccio Martina , Rizzi Alessandro , Kayacan Mevlüt Y. , Vedani Maurizio
Published: December 2020

The number of available materials for Laser Powder Bed Fusion is still limited due to the poor processability of many standard alloys. In particular, the lack of high-strength aluminium alloys, widely used in aerospace and automotive industries, remains a big issue for the spread of beam-based additive manufacturing technologies. In this study, a novel high-strength aluminium alloy for high temperature applications having good processability was developed. The design of the alloy was done based on the chemical composition of the widely used EN AW 2618. This Al-Cu-Mg-Ni-Fe alloy was modified with Ti and B in order to promote the formation of TiB2 nuclei in the liquid phase able to stimulate heterogeneous nucleation of grains and to decrease the hot cracking susceptibility of the material. The new Al alloy was manufactured by gas atomisation and processed by Laser Powder Bed Fusion. Samples produced with optimised parameters featured relative density of 99.91%, with no solidification cracks within their microstructure. After aging, the material revealed upper yield strength and ultimate tensile strength of 495 MPa and 460 MPa, respectively. In addition, the alloy showed tensile strength higher than wrought EN AW 2618 at elevated temperatures.
Understanding Size Effects and Forming Limits in the Micro-Stamping of Industrial Stainless Steel Foils
Authors: Weiss Matthias , Zhang Peng , Pereira Michael P. , Rolfe Bernard F. , Wilkosz Daniel E. , Hodgson Peter D.
Published: December 2020

This study investigates the effect of grain size and composition on the material properties and forming limits of commercially supplied stainless steel foil for bipolar plate manufacture via tensile, stretch forming and micro-stamping trials. It is shown that in commercially supplied stainless steel the grain size can vary significantly and that ‘size effects’ can be influenced by prior steel processing and composition effects. While the forming limits in micro-stamping appear to be directly linked to the plane strain forming limits of the individual stainless steel alloys, there was a clear effect of the tensile anisotropy. In contrast to previous studies, forming severity and the likelihood of material failure did not increase with a decreasing channel profile radius. This was related to inaccuracies of the forming tool profile shape.
Influence of Parameters on the Pre-Reduction Process of Vanadium-Titanium Magnetite Carbon-Containing Composite Pellets in Rotary Kiln
Authors: Wang Bo , Ding Xueyong , Ju Tianhua , Zhang Xiaofei , Cheng Gongjin
Published: December 2020

A novel smelting reduction process called pre-reduction in rotary kiln and total oxygen melting pool is a promising route to reduce environmental pollution from the ironmaking industry. In this paper, the process parameters and appropriate efficiency of reduction in the pre-reduction process of the rotary kiln were investigated via the detection of the metallization rate, phase composition, and internal morphology of the product combining with the analysis of the off-gas. The results indicated that the parameters of reduction temperature, reduction holding time, and coal ratio have a remarkable influence on the metallization rate. The reduction temperature has the most significant effect, followed by the reduction time and the coal ratio. Furthermore, under the condition of reduction temperature 1000 °C, holding time 30 min, coal ratio = 1, a product with a metallization rate of more than 70% can be obtained, which meets the requirements of the rotary kiln process, and its CO2/CO value of the pre-reduction endpoint is appropriate. Continue to increase the temperature, holding time, and coal ratio can raise the metallization rate of the pellets, but only a little improvement and may cause reoxidation of the product.
Wear and Fretting Behavior of Cold Sprayed IN625 Superalloy
Authors: Cavaliere Pasquale Daniele , Rizzo Antonella , Valerini Daniele , Capodieci Laura
Published: December 2020

The wear and fretting behaviour of IN625 cold spray coatings was analysed and the results are presented. The cold spray conditions were selected in order to obtain coatings with minimum porosity and maximum particles splat. This leads to compact and hard deposited material able to resist wear damaging and to dissipate energy during fretting. The coating’s strength was evaluated through nanoindentation that revealed an increased hardness from the surface toward the substrate. This different hardening behaviour from the coating surface toward the substrate leads to increased resistance to fretting and wear as the maximum stresses increase. This was revealed by scratch tests performed at linearly increasing loads that allowed identifying of the damage mechanisms acting on the coating as the triaxial stresses increase. The hardening behaviour of the coating also influenced the fretting behaviour revealed by the weight loss experienced by varying the fretting maximum load.
Osmotic Adaptation and Compatible Solute Biosynthesis of Phototrophic Bacteria as Revealed from Genome Analyses
Authors: Imhoff Johannes F. , Rahn Tanja , Künzel Sven , Keller Alexander , Neulinger Sven C.
Published: December 2020

Osmotic adaptation and accumulation of compatible solutes is a key process for life at high osmotic pressure and elevated salt concentrations. Most important solutes that can protect cell structures and metabolic processes at high salt concentrations are glycine betaine and ectoine. The genome analysis of more than 130 phototrophic bacteria shows that biosynthesis of glycine betaine is common among marine and halophilic phototrophic Proteobacteria and their chemotrophic relatives, as well as in representatives of Pirellulaceae and Actinobacteria, but are also found in halophilic Cyanobacteria and Chloroherpeton thalassium. This ability correlates well with the successful toleration of extreme salt concentrations. Freshwater bacteria in general lack the possibilities to synthesize and often also to take up these compounds. The biosynthesis of ectoine is found in the phylogenetic lines of phototrophic Alpha- and Gammaproteobacteria, most prominent in the Halorhodospira species and a number of Rhodobacteraceae. It is also common among Streptomycetes and Bacilli. The phylogeny of glycine-sarcosine methyltransferase (GMT) and diaminobutyrate-pyruvate aminotransferase (EctB) sequences correlate well with otherwise established phylogenetic groups. Most significantly, GMT sequences of cyanobacteria form two major phylogenetic branches and the branch of Halorhodospira species is distinct from all other Ectothiorhodospiraceae. A variety of transport systems for osmolytes are present in the studied bacteria.
Is Gut Microbiota Dysbiosis a Predictor of Increased Susceptibility to Poor Outcome of COVID-19 Patients? An Update
Authors: Ferreira Carolina , Viana Sofia D. , Reis Flávio
Published: December 2020

The scientific knowledge already attained regarding the way severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infects human cells and the clinical manifestations and consequences for Coronavirus Disease 2019 (COVID-19) patients, especially the most severe cases, brought gut microbiota into the discussion. It has been suggested that intestinal microflora composition plays a role in this disease because of the following: (i) its relevance to an efficient immune system response; (ii) the fact that 5–10% of the patients present gastrointestinal symptoms; and (iii) because it is modulated by intestinal angiotensin-converting enzyme 2 (ACE2) (which is the virus receptor). In addition, it is known that the most severely affected patients (those who stay longer in hospital, who require intensive care, and who eventually die) are older people with pre-existing cardiovascular, metabolic, renal, and pulmonary diseases, the same people in which the prevalence of gut microflora dysbiosis is higher. The COVID-19 patients presenting poor outcomes are also those in which the immune system’s hyperresponsiveness and a severe inflammatory condition (collectively referred as “cytokine storm”) are particularly evident, and have been associated with impaired microbiota phenotype. In this article, we present the evidence existing thus far that may suggest an association between intestinal microbiota composition and the susceptibility of some patients to progress to severe stages of the disease.
β-Galactosidases from a Sequence-Based Metagenome: Cloning, Expression, Purification and Characterization
Authors: Eberhardt María Florencia , Irazoqui José Matías , Amadio Ariel Fernando
Published: December 2020

Stabilization ponds are a common treatment technology for wastewater generated by dairy industries. Large proportions of cheese whey are thrown into these ponds, creating an environmental problem because of the large volume produced and the high biological and chemical oxygen demands. Due to its composition, mainly lactose and proteins, it can be considered as a raw material for value-added products, through physicochemical or enzymatic treatments. β-Galactosidases (EC 3.2.1.23) are lactose modifying enzymes that can transform lactose in free monomers, glucose and galactose, or galactooligosacharides. Here, the identification of novel genes encoding β-galactosidases, identified via whole-genome shotgun sequencing of the metagenome of dairy industries stabilization ponds is reported. The genes were selected based on the conservation of catalytic domains, comparing against the CAZy database, and focusing on families with β-galactosidases activity (GH1, GH2 and GH42). A total of 394 candidate genes were found, all belonging to bacterial species. From these candidates, 12 were selected to be cloned and expressed. A total of six enzymes were expressed, and five cleaved efficiently ortho-nitrophenyl-β-galactoside and lactose. The activity levels of one of these novel β-galactosidase was higher than other enzymes reported from functional metagenomics screening and higher than the only enzyme reported from sequence-based metagenomics. A group of novel mesophilic β-galactosidases from diary stabilization ponds’ metagenomes was successfully identified, cloned and expressed. These novel enzymes provide alternatives for the production of value-added products from dairy industries’ by-products.
Weathering Processes and Mechanisms Caused by Capillary Waters and Pigeon Droppings on Porous Limestones
Authors: Benavente David , de Jongh Marli , Cañaveras Juan Carlos
Published: December 2020

This investigation studies the physical and chemical effect of salt weathering on biocalcarenites and biocalcrudites in the Basilica of Our Lady of Succour (Aspe, Spain). Weathering patterns are the result of salty rising capillary water and water lixiviated from pigeon droppings. Surface modifications and features induced by material loss are observable in the monument. Formation of gypsum, hexahydrite, halite, aphthitalite and arcanite is associated with rising capillary water, and niter, hydroxyapatite, brushite, struvite, weddellite, oxammite and halite with pigeon droppings. Humberstonite is related to the interaction of both types of waters. Analysis of crystal shapes reveals different saturation degree conditions. Single salts show non-equilibrium shapes, implying higher crystallisation pressures. Single salts have undergone dissolution and/or dehydration processes enhancing the deterioration process, particularly in the presence of magnesium sulphate. Double salts (humberstonite) have crystals corresponding to near-equilibrium form, implying lower crystallisation pressures. This geochemical study suggests salts precipitate via incongruent reactions rather than congruent precipitation, where hexahydrite is the precursor and limiting reactant of humberstonite. Chemical dissolution of limestone is driven mainly by the presence of acidic water lixiviated from pigeon droppings and is a critical weathering process affecting the most valuable architectural elements present in the façades.
Editorial for Special Issue “Metallurgical Slags”
Authors: Kierczak Jakub , Ettler Vojtĕch
Published: December 2020

Exploitation and further processing of mineral resources are of great importance for modern society [...]
Fabricating Femtosecond Laser-Induced Periodic Surface Structures with Electrophysical Anisotropy on Amorphous Silicon
Authors: Shuleiko Dmitrii , Martyshov Mikhail , Amasev Dmitrii , Presnov Denis , Zabotnov Stanislav , Golovan Leonid , Kazanskii Andrei , Kashkarov Pavel
Published: December 2020

One-dimensional periodic surface structures were formed by femtosecond laser irradiation of amorphous hydrogenated silicon (a-Si:H) films. The a-Si:H laser processing conditions influence on the periodic relief formation as well as correlation of irradiated surfaces structural properties with their electrophysical properties were investigated. The surface structures with the period of 0.88 and 1.12 μm were fabricated at the laser wavelength of 1.25 μm and laser pulse number of 30 and 750, respectively. The orientation of the surface structure is defined by the laser polarization and depends on the concentration of nonequilibrium carriers excited by the femtosecond laser pulses in the near-surface region of the film, which affects a mode of the excited surface electromagnetic wave which is responsible for the periodic relief formation. Femtosecond laser irradiation increases the a-Si:H films conductivity by 3 to 4 orders of magnitude, up to 1.2 × 10−5 S∙cm, due to formation of Si nanocrystalline phase with the volume fraction from 17 to 28%. Dark conductivity and photoconductivity anisotropy, observed in the irradiated a-Si:H films is explained by a depolarizing effect inside periodic microscale relief, nonuniform crystalline Si phase distribution, as well as different carrier mobility and lifetime in plane of the studied samples along and perpendicular to the laser-induced periodic surface structures orientation, that was confirmed by the measured photoconductivity and absorption coefficient spectra.
Hysteresis Analysis of Hole-Transport-Material-Free Monolithic Perovskite Solar Cells with Carbon Counter Electrode by Current Density–Voltage and Impedance Spectra Measurements
Authors: Shah Syed Afaq Ali , Sayyad Muhammad Hassan , Sun Jinghua , Guo Zhongyi
Published: December 2020

Due to the tremendous increase in power conversion efficiency (PCE) of organic–inorganic perovskite solar cells (PSCs), this technology has attracted much attention. Despite being the fastest-growing photovoltaic technology to date, bottlenecks such as current density–voltage (J–V) hysteresis have significantly limited further development. Current density measurements performed with different sweep scan speeds exhibit hysteresis and the photovoltaic parameters extracted from the current density–voltage measurements for both scan directions become questionable. A current density–voltage measurement protocol needs to be established which can be used to achieve reproducible results and to compare devices made in different laboratories. In this work, we report a hysteresis analysis of a hole-transport-material-free (HTM-free) carbon-counter-electrode-based PSC conducted by current density–voltage and impedance spectra measurements. The effect of sweep scan direction and time delay was examined on the J–V characteristics of the device. The hysteresis was observed to be strongly sweep scan direction and time delay dependent and decreased as the delay increased. The J–V analysis conducted in the reverse sweep scan direction at a lower sweep time delay of 0.2 s revealed very large increases in the short circuit current density and the power conversion efficiency of 57.7% and 56.1%, respectively, compared with the values obtained during the forward scan under the same conditions. Impedance spectroscopy (IS) investigations were carried out and the effects of sweep scan speed, time delay, and frequency were analyzed. The hysteresis was observed to be strongly sweep scan direction, sweep time delay, and frequency dependent. The correlation between J–V and IS data is provided. The wealth of photovoltaic and impendence spectroscopic data reported in this work on the hysteresis study of the HTM-free PSC may help in establishing a current density–voltage measurement protocol, identifying components and interfaces causing the hysteresis, and modeling of PSCs, eventually benefiting device performance and long-term stability.
A Novel Thermochemical Metal Halide Treatment for High-Performance Sb2Se3 Photocathodes
Authors: Polivtseva Svetlana , Adegite Joseph Olanrewaju , Kois Julia , Mamedov Damir , Karazhanov Smagul Zh. , Maricheva Jelena , Volobujeva Olga
Published: December 2020

The fabrication of cost-effective photostable materials with optoelectronic properties suitable for commercial photoelectrochemical (PEC) water splitting represents a complex task. Herein, we present a simple route to produce Sb2Se3 that meets most of the requirements for high-performance photocathodes. Annealing of Sb2Se3 layers in a selenium-containing atmosphere persists as a necessary step for improving device parameters; however, it could complicate industrial processability. To develop a safe and scalable alternative to the selenium physical post-processing, we propose a novel SbCl3/glycerol-based thermochemical treatment for controlling anisotropy, a severe problem for Sb2Se3. Our procedure makes it possible to selectively etch antimony-rich oxyselenide presented in Sb2Se3, to obtain high-quality compact thin films with a favorable morphology, stoichiometric composition, and crystallographic orientation. The treated Sb2Se3 photoelectrode demonstrates a record photocurrent density of about 31 mA cm−2 at −248 mV against the calomel electrode and can thus offer a breakthrough option for industrial solar fuel fabrication.
A Theoretical Study of the Occupied and Unoccupied Electronic Structure of High- and Intermediate-Spin Transition Metal Phthalocyaninato (Pc) Complexes: VPc, CrPc, MnPc, and FePc
Authors: Carlotto Silvia , Sambi Mauro , Sedona Francesco , Vittadini Andrea , Casarin Maurizio
Published: December 2020

The structural, electronic, and spectroscopic properties of high- and intermediate-spin transition metal phthalocyaninato complexes (MPc; M = V, Cr, Mn and Fe) have been theoretically investigated to look into the origin, symmetry and strength of the M–Pc bonding. DFT calculations coupled to the Ziegler’s extended transition state method and to an advanced charge density and bond order analysis allowed us to assess that the M–Pc bonding is dominated by σ interactions, with FePc having the strongest and most covalent M–Pc bond. According to experimental evidence, the lightest MPcs (VPc and CrPc) have a high-spin ground state (GS), while the MnPc and FePc GS spin is intermediate. Insights into the MPc unoccupied electronic structure have been gained by modelling M L2,3-edges X-ray absorption spectroscopy data from the literature through the exploitation of the current Density Functional Theory variant of the Restricted Open-Shell Configuration Interaction Singles (DFT/ROCIS) method. Besides the overall agreement between theory and experiment, the DFT/ROCIS results indicate that spectral features lying at the lowest excitation energies (EEs) are systematically generated by electronic states having the same GS spin multiplicity and involving M-based single electronic excitations; just as systematically, the L3-edge higher EE region of all the MPcs herein considered includes electronic states generated by metal-to-ligand-charge-transfer transitions involving the lowest-lying π* orbital (7eg) of the phthalocyaninato ligand.
Rifabutin for the Treatment of Helicobacter pylori Infection: A Review
Authors: Gisbert Javier P.
Published: December 2020

Nowadays, apart from having to know first-line Helicobacter pylori eradication regimens well, we must also be prepared to face treatment failures. The aim of this review is to summarize the role of rifabutin in the management of H. pylori infection. Bibliographical searches were performed in PubMed. Data on resistance and efficacy of rifabutin-containing regimens on H. pylori eradication were meta-analyzed. Mean H. pylori rifabutin resistance rate (39 studies, including 9721 patients) was 0.13%; when studies only including patients naïve to H. pylori eradication treatment were considered, this figure was even lower (0.07%). Mean H. pylori eradication rate (by intention-to-treat) with rifabutin-containing regimens (3052 patients) was 73%. Respective cure rates for second-, third-, fourth- and fifth-line therapies, were 79%, 69%, 69% and 72%. Most studies administered rifabutin 300 mg/day, which seemed to be more effective than 150 mg/day. The ideal length of treatment remains unclear, but 10–12-day regimens are generally recommended. Adverse events to rifabutin treatment in H. pylori studies were relatively infrequent (15%), and severe adverse events were exceptional (myelotoxicity was the most significant, although always reversible). In summary, rifabutin-containing therapy represents an encouraging strategy generally restricted, at present, to patients where previous (usually multiple) eradication regimens have failed.
Mutations Found in the Asc1 Gene That Confer Susceptibility to the AAL-Toxin in Ancestral Tomatoes from Peru and Mexico
Authors: Tsuzuki Rin , Cabrera Pintado Rosa María , Biondi Thorndike Jorge Andrés , Gutiérrez Reynoso Dina Lida , Amasifuen Guerra Carlos Alberto , Guerrero Abad Juan Carlos , Aragón Caballero Liliana Maria , Huarhua Zaquinaula Medali Heidi , Ureta Sierra Cledy , Alberca Cruz Olenka Ines , Elespuru Suna Milca Gianira , Blas Sevillano Raúl Humberto , Torres Arias Ines Carolina , Flores Ticona Joel , de Baldárrago Fátima Cáceres , Pérez Enrique Rodoríguez , Hozum Takuo , Saito Hiroki , Kotera Shunsuke , Akagi Yasunori , Kodama Motoichiro , Komatsu Ken , Arie Tsutomu
Published: December 2020

Tomato susceptibility/resistance to stem canker disease caused by Alternaria alternata f. sp. lycopersici and its pathogenic factor AAL-toxin is determined by the presence of the Asc1 gene. Several cultivars of commercial tomato (Solanum lycopersicum var. lycopersicum, SLL) are reported to have a mutation in Asc1, resulting in their susceptibility to AAL-toxin. We evaluated 119 ancestral tomato accessions including S. pimpinellifolium (SP), S. lycopersicum var. cerasiforme (SLC) and S. lycopersicum var. lycopersicum “jitomate criollo” (SLJ) for AAL-toxin susceptibility. Three accessions, SP PER018805, SLC PER018894, and SLJ M5-3, were susceptible to AAL-toxin. SLC PER018894 and SLJ M5-3 had a two-nucleotide deletion (nt 854_855del) in Asc1 identical to that found in SLL cv. Aichi-first. Another mutation (nt 931_932insT) that may confer AAL-toxin susceptibility was identified in SP PER018805. In the phylogenetic tree based on the 18 COSII sequences, a clade (S3) is composed of SP, including the AAL-toxin susceptible PER018805, and SLC. AAL-toxin susceptible SLC PER018894 and SLJ M5-3 were in Clade S2 with SLL cultivars. As SLC is thought to be the ancestor of SLL, and SLJ is an intermediate tomato between SLC and SLL, Asc1s with/without the mutation seem to have been inherited throughout the history of tomato domestication and breeding.
Application of Exogenous Phytohormones at Silking Stage Improve Grain Quality under Post-Silking Drought Stress in Waxy Maize
Authors: Wang Longfei , Yan Yini , Lu Weiping , Lu Dalei
Published: December 2020

The application of exogenous plant growth regulator can improve plant resistance to drought stress. The effects of application of exogenous cytokinin (CTK), brassinolide (BR), or gibberellic acid (GA) at the silking time on the grain quality of two waxy maize hybrids under drought stress at grain formation stage were studied. Grain weight of both hybrids was unaffected by exogenous phytohormones under control conditions but increased under drought conditions with the application of BR. The grain starch content in response to drought varied with hybrid and phytohormone. Starch granule size and protein content in grains were increased by drought under all conditions, but various phytohormones exerted different forms of influence. The starch λmax in Yunuo7 was unaffected by single or interaction of phytohormones and water deficit, λmax in Jingkenuo2000 with BR was unaffected but with CTK or GA increased by drought. Relative crystallinity was reduced by drought without the application of phytohormone, but with phytohormones in response to drought it was different. Flour peak viscosity was reduced by drought. The value was increased with BR spraying under control and drought conditions. Retrogradation percentage under drought conditions was unaffected by exogenous phytohormones in Jingkenuo2000. In Yunuo7, retrogradation percentage was unaffected by BR but reduced by CTK and GA. In conclusion, spraying phytohormones at the silking stage can affect grain weight and starch quality, grains with a sticky taste can be improved by applying BR, and grains with low retrograde tendency can be produced by applying CTK.
Bond Structures between Wood Components and Citric Acid in Wood-Based Molding
Authors: Ando Daisuke , Umemura Kenji
Published: December 2020

Citric acid-based wood adhesive is considered a chemical-bonding wood adhesive. However, the detailed structures of the bonds between wood components and citric acid remain unknown. Here, we examine the chemical bonding structures between citric acid and wood by heteronuclear single quantum coherence-nuclear magnetic resonance (HSQC-NMR) analysis of wood-based molding using Japanese cedar (Cryptomeria japonica) and citric acid. In the HSQC-NMR spectrum of the wood molding, some esterified C/H correlation peaks appeared. The primary hydroxyl groups of polysaccharides, such as cellulose and galactoglucomannan, and the primary hydroxyl groups of the β-O-4 and β-5 substructures in lignin were found to be esterified with citric acid. In contrast, the secondary hydroxyl groups, except for xylan, barely reacted because of the steric hindrance. Additionally, the C/H correlation peak volumes of the reducing ends of mannan and xylan in the anomeric region increased after molding. It was clarified that the glycosidic bonds in the hemicelluloses were cleaved under the acidic molding condition with citric acid. The HSQC-NMR analysis revealed that the esterification of hemicellulose and lignin, and degradation of hemicellulose, proceeded under the molding condition. These results will promote understanding of the adhesive mechanism of citric acid-based wood adhesive and of the properties of the molding.
Architectures and Applications of BODIPY-Based Conjugated Polymers
Authors: Fan Yiqi , Zhang Jinjin , Hong Zhouyi , Qiu Huayu , Li Yang , Yin Shouchun
Published: December 2020

Conjugated polymers generally contain conjugated backbone structures with benzene, heterocycle, double bond, or triple bond, so that they have properties similar to semiconductors and even conductors. Their energy band gap is very small and can be adjusted via chemical doping, allowing for excellent photoelectric properties. To obtain prominent conjugated materials, numerous well-designed polymer backbones have been reported, such as polyphenylenevinylene, polyphenylene acetylene, polycarbazole, and polyfluorene. 4,4′-Difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-based conjugated polymers have also been prepared owing to its conjugated structure and intriguing optical properties, including high absorption coefficients, excellent thermal/photochemical stability, and high quantum yield. Most importantly, the properties of BODIPYs can be easily tuned by chemical modification on the dipyrromethene core, which endows the conjugated polymers with multiple functionalities. In this paper, BODIPY-based conjugated polymers are reviewed, focusing on their structures and applications. The forms of BODIPY-based conjugated polymers include linear, coiled, and porous structures, and their structure–property relationship is explored. Also, typical applications in optoelectronic materials, sensors, gas/energy storage, biotherapy, and bioimaging are presented and discussed in detail. Finally, the review provides an insight into the challenges in the development of BODIPY-based conjugated polymers.
Plant-Based Tacca leontopetaloides Biopolymer Flocculant (TBPF) Produced High Removal of Heavy Metal Ions at Low Dosage
Authors: Mohd Makhtar Nurul Shuhada , Idris Juferi , Musa Mohibah , Andou Yoshito , Ku Hamid Ku Halim , Puasa Siti Wahidah
Published: December 2020

High removal of heavy metals using plant-based bioflocculant under low concentration is required due to its low cost, abundant source, and nontoxicity for improved wastewater management and utilization in the water industry. This paper presents a treatment of synthetic wastewater using plant-based Tacca leontopetaloides biopolymer flocculant (TBPF) without modification on its structural polymer chains. It produced a high removal of heavy metals (Zn, Pb, Ni, and Cd) at a low concentration of TBPF dosage. In our previous report, TBPF was characterized and successfully reduced the turbidity, total suspended solids, and color for leachate treatment; however, its effectiveness for heavy metal removal has not been reported. The removal of these heavy metals was performed using a standard jar test procedure at different pH values of synthetic wastewater and TBPF dosages. The effects of hydroxide ion, pH, initial TBPF concentration, initial metal ion concentration, and TBPF dosage were examined using one factorial at the time (OFAT). The results show that the highest removal for Zn, Pb, Ni, and Cd metal ions were 98.4–98.5%, 79–80%, 97–98%, and 92–93%, respectively, using 120 mg/L dosage from the initial concentration of 10% TBPF at pH 10. The final concentrations for Zn, Pb, Ni, and Cd metal ions were 0.043–0.044, 0.41–0.43, 0.037–0.054, and 0.11–0.13 mg/L, respectively, which are below the Standard B discharge limit set by the Department of Environment (DOE), Malaysia. The results show that TBPF has a high potential for the removal of heavy metals, particularly Zn, Pb, Ni, and Cd, in real wastewater treatment.
Ideal Feedstock and Fermentation Process Improvements for the Production of Lignocellulolytic Enzymes
Authors: Iram Attia , Cekmecelioglu Deniz , Demirci Ali
Published: December 2020

The usage of lignocellulosic biomass in energy production for biofuels and other value-added products can extensively decrease the carbon footprint of current and future energy sectors. However, the infrastructure in the processing of lignocellulosic biomass is not well-established as compared to the fossil fuel industry. One of the bottlenecks is the production of the lignocellulolytic enzymes. These enzymes are produced by different fungal and bacterial species for degradation of the lignocellulosic biomass into its reactive fibers, which can then be converted to biofuel. The selection of an ideal feedstock for the lignocellulolytic enzyme production is one of the most studied aspects of lignocellulolytic enzyme production. Similarly, the fermentation enhancement strategies for different fermentation variables and modes are also the focuses of researchers. The implementation of fermentation enhancement strategies such as optimization of culture parameters (pH, temperature, agitation, incubation time, etc.) and the media nutrient amendment can increase the lignocellulolytic enzyme production significantly. Therefore, this review paper summarized these strategies and feedstock characteristics required for hydrolytic enzyme production with a special focus on the characteristics of an ideal feedstock to be utilized for the production of such enzymes on industrial scales.
Advances and Gaps in Natech Quantitative Risk Analysis
Authors: Mesa-Gómez Adriana , Casal Joaquim , Sánchez-Silva Mauricio , Muñoz Felipe
Published: December 2020

The occurrence of Natech (natural hazard triggering technological disasters) accidents has generated a reflection about the need to manage adequately the risk to people, to the environment, and to the infrastructures subjected to natural events. For this reason, academia and industry have increased research in the process safety area in the last decade, strengthening quantitative risk analysis (QRA) methodologies for Natech events. However, these methodologies have some gaps that must be closed for a better decision-making process. In this communication a comparative analysis of the existing Natech QRA approaches is done, to highlight features and differences and to identify main gaps that should be addressed in future research. It can be mentioned that all the analyzed methodologies, which have been applied to floods, earthquakes, and lightning, are based on an initial one developed in 2007. The critical gap is that in all these methodologies, the final step is the risk calculation based on fatalities, and they do not consider the area-wide as an essential element in the risk analysis process.
Evaluation of Novel Bio-Based Amino Curing Agent Systems for Epoxy Resins: Effect of Tryptophan and Guanine
Authors: Merighi Stefano , Mazzocchetti Laura , Benelli Tiziana , Giorgini Loris
Published: December 2020

In order to obtain an environmentally friendly epoxy system, L-tryptophan and guanine were investigated as novel green curing agents for the cross-link of diglycidyl ether of Bisphenol A (DGEBA) as a generic epoxy resin model of synthetic and analogous bio-based precursors. In particular, L-tryptophan, which displays high reaction temperature with DGEBA, was used in combination with various bio-based molecules such as urea, theobromine, theophylline, and melamine in order to increase the thermal properties of the epoxy resin and to reduce the crosslinking reaction temperature. Later, in order to obtain similar properties using a single product, guanine, a totally heterocyclic molecule displaying amine functional groups, was tested as hardener for DGEBA. The thermal behavior of the precursor mixtures was evaluated by dynamic differential scanning calorimetry (DSC) leading to a preliminary screening of different hardening systems which offered a number of interesting hints in terms of bio-based compounds able to provide high Tg resins. These encouraging results pave the way for a further study of a new class of renewable, low-toxic, and sustainable curing agent systems for the production of fully bio-based epoxy resins.