bluuebunny/crossref_metadata_2025 huggingface dataset:
Science and Technology of High Performance Ferritic (HiperFer) Stainless Steels
Authors: Kuhn Bernd , Talik Michal , Fischer Torsten , Fan Xiuru , Yamamoto Yukinori , Lopez Barrilao Jennifer
Published: April 2020

Future, flexible thermal energy conversion systems require new, demand-optimized high-performance materials. The High performance Ferritic (HiperFer) stainless steels, under development at the Institute of Microstructure and Properties of Materials (IEK-2) at Forschungszentrum Jülich GmbH in Germany, provide a balanced combination of fatigue, creep and corrosion resistance at reasonable price. This paper outlines the scientific background of alloy performance development, which resulted in an age-hardening ferritic, stainless steel grade. Furthermore, technological properties are addressed and the potential concerning application is estimated by benchmarking versus conventional state of the art materials.
Extraction of Lead and Zinc from a Rotary Kiln Oxidizing Roasting Cinder
Authors: Xiao Junhui , Zou Kai , Ding Wei , Peng Yang , Chen Tao
Published: April 2020

In this study, sulfuric acid leaching and gravity shaking-table separation by shaking a table are used to extract lead and zinc from a Pb-Zn oxidizing roasting cinder. The oxidizing roasting cinder—containing 16.9% Pb, 30.5% Zn, 10.3% Fe and 25.1% S—was obtained from a Pb-Zn sulfide ore in the Hanyuan area of China by a flotation-rotary kiln oxidizing roasting process. Anglesite and lead oxide were the main Pb-bearing minerals, while zinc sulfate, zinc oxide and zinc ferrite were the main Zn-bearing minerals. The results show that a part of lead contained in lead oxide is transformed to anglesite, and a 3PbO·PbSO4·H2O-dominated new lead mineral phase after acid leaching. A zinc leaching efficiency of 96.7% was obtained under the leaching conditions used: a leaching temperature of 55 °C; a leaching time of 90 min; a sulfuric acid dosage of 20%; a sulfurous acid dosage of 4%; a cinder particle size of <0.3 mm; and a solid-liquid ratio of R = 1:4. After the gravity shaking-table separation, a lead concentrate with 50.2% Pb, 2.33% Zn and lead recovery of 86.0% was produced. The main chemical compounds in leaching residue are anglesite, 3PbO·PbSO4·H2O, SiO2 and ZnFe2O4, while the main chemical compounds in lead concentrate are anglesite, 3PbO·PbSO4·H2O and SiO2.
Electrical and Mechanical Analysis of Different TSV Geometries
Authors: Jeong Il Ho , Eslami Majd Alireza , Jung Jae Pil , Ekere Nduka Nnamdi
Published: April 2020

Through-silicon via (TSV) is an important component for implementing 3-D packages and 3-D integrated circuits as the TSV technology allows stacked silicon chips to interconnect through direct contact to help facilitate high-speed signal processing. By facilitating the stacking of silicon chips, the TSV technology also helps to meet the increasing demand for high density and high performance miniaturized electronic products. Our review of the literature shows that very few studies have reported on the impact of TSV bump geometry on the electrical and mechanical characteristics of the TSV. This paper reports on the investigation of different TSV geometries with the focus on identifying the ideal shapes for improved electrical signal transmission as well as for improved mechanical reliability. The cylindrical, quadrangular (square), elliptical, and triangular shapes were investigated in our study and our results showed that the quadrangular shape had the best electrical performance due to good characteristic impedance. Our results also showed that the quadrangular and cylindrical shapes provided improved mechanical reliability as these two shapes lead to high Cu protrusion of TSV after the annealing process.
Effect of Pore Defects on Mechanical Properties of Graphene Reinforced Aluminum Nanocomposites
Authors: Li Duosheng , Song Shengli , Zuo Dunwen , Wu Wenzheng
Published: April 2020

Pore defects have an important effect on the mechanical properties of graphene reinforced aluminum nanocomposites. The simulation study found that the pores affect the stress distribution in the matrix of the composite. Along the stretching direction, the larger stress appears on both sides of the pore, which is the source of potential cracks. It results in a sharp decrease in the mechanical properties of the composite. The higher the porosity, the greater the tendency of pore aggregation, and the risk of material failure is higher. The stress distribution in the matrix becomes more uneven as the pore size increases, and the large strain area around the pores also increases. Composites with circular pores have a higher strength than other irregularly shaped pores. The failure mode might be pore cracking, while composites with other shape pores are more prone to interface detachment. The simulation value of the stress-strain of the composite material is in good agreement with the experimental value, but the finite element simulation value is larger than the experimental value.
An Integrative Approach to Assessing Diet–Cancer Relationships
Authors: Murphy Rachel
Published: April 2020

The relationship between diet and cancer is often viewed with skepticism by the public and health professionals, despite a considerable body of evidence and general consistency in recommendations over the past decades. A systems biology approach which integrates ‘omics’ data including metabolomics, genetics, metagenomics, transcriptomics and proteomics holds promise for developing a better understanding of how diet affects cancer and for improving the assessment of diet through biomarker discovery thereby renewing confidence in diet–cancer links. This review discusses the application of multi-omics approaches to studies of diet and cancer. Considerations and challenges that need to be addressed to facilitate the investigation of diet–cancer relationships with multi-omic approaches are also discussed.
Bile Acid Profile and its Changes in Response to Cefoperazone Treatment in MR1 Deficient Mice
Authors: Sun Jinchun , Cao Zhijun , Smith Ashley D. , Carlson Jr Paul E. , Coryell Michael , Chen Huizhong , Beger Richard D.
Published: April 2020

Mucosal associated invariant T-cells (MAIT cells) are activated following recognition of bacterial antigens (riboflavin intermediates) presented on major histocompatibility complex class I-related molecule (MR1). Our previous study showed that MR1−/− knock-out (KO) mice (lacking MAIT cells) harbor a unique microbiota that is resistant to antibiotic disruption and Clostridioides difficile colonization. While we have characterized the microbiota of this mouse strain, changes in global metabolic activity in these KO mice have not been assessed. Here, LC/MS-based untargeted metabolomics was applied to investigate the differences in the metabolome, specifically in the bile acid (BA) profile of wild-type (WT) and MR1−/− KO mice, as well as how antibiotics change these profiles. BA changes were evaluated in the intestinal content, cecum content, and stool samples from MR1−/− mice and WT mice treated with cefoperazone (Cef). Fecal pellets were collected daily and both intestinal and cecal contents were harvested at predetermined endpoints on day 0 (D0), day 1 (D1), day 3 (D3), and day 5 (D5). KO mice exhibited no changes in 6-hydroxymethyl-8-D-ribityllumazine (rRL-6-CH2OH; an MR1-restricted riboflavin derivative) in the stool samples at either time point vs. D0, while WT mice showed significant decreases in rRL-6-CH2OH in the stool samples on all treatment days vs. D0. Metabolomics analysis from cecal and stool samples showed that KO mice had more total BA intensity (KO/WT = ~1.7 and ~3.3 fold higher) than that from WT mice prior to Cef treatment, while the fold change difference (KO/WT = ~4.5 and ~4.4 fold) increased after five days of Cef treatment. Both KO and WT mice showed decreases in total BA intensity in response to Cef treatment, however, less dramatic decreases were present in KO vs. WT mice. Increases in taurocholic acid (TCA) intensity and decreases in deoxycholic acid (DCA) intensity in the stool samples from WT mice were associated with the depletion of certain gut bacteria, which was consistent with the previously reported microbiome data. Furthermore, the non-detected TCA and relatively higher DCA intensity in the KO mice might be related to Clostridioides difficile infection resistance, although this needs further investigation.
Current Concepts in Pharmacometabolomics, Biomarker Discovery, and Precision Medicine
Authors: Beger Richard D. , Schmidt Michael A , Kaddurah-Daouk Rima
Published: April 2020

Pharmacometabolomics (PMx) studies use information contained in metabolic profiles (or metabolome) to inform about how a subject will respond to drug treatment. Genome, gut microbiome, sex, nutrition, age, stress, health status, and other factors can impact the metabolic profile of an individual. Some of these factors are known to influence the individual response to pharmaceutical compounds. An individual’s metabolic profile has been referred to as his or her “metabotype.” As such, metabolomic profiles obtained prior to, during, or after drug treatment could provide insights about drug mechanism of action and variation of response to treatment. Furthermore, there are several types of PMx studies that are used to discover and inform patterns associated with varied drug responses (i.e., responders vs. non-responders; slow or fast metabolizers). The PMx efforts could simultaneously provide information related to an individual’s pharmacokinetic response during clinical trials and be used to predict patient response to drugs making pharmacometabolomic clinical research valuable for precision medicine. PMx biomarkers can also be discovered and validated during FDA clinical trials. Using biomarkers during medical development is described in US Law under the 21st Century Cures Act. Information on how to submit biomarkers to the FDA and their context of use is defined herein.
Synthesis and Biological Evaluation of Imidazo[2,1-b]Thiazole based Sulfonyl Piperazines as Novel Carbonic Anhydrase II Inhibitors
Authors: Manasa Kesari Lakshmi , Pujitha Sravya , Sethi Aaftaab , Arifuddin Mohammed , Alvala Mallika , Angeli Andrea , Supuran Claudiu T.
Published: April 2020

A novel series of imidazo[2,1-b]thiazole-sulfonyl piperazine conjugates (9aa-ee) has been synthesized and evaluated for carbonic anhydrase (CA, EC 4.2.1.1) inhibitory potency against four isoforms: The cytosolic isozyme hCA I, II and trans-membrane tumor-associated isoform hCA IX and hCA XII, taking acetazolamide (AAZ) as standard drug, using a stopped flow CO2 hydrase assay. The results revealed that most of the compounds showed selective activity against hCA II whereas none of them were active against hCA I, IX, XII (Ki > 100 µM). The physiologically dominant cytosolic isoform hCA II was inhibited by these molecules with inhibition constants in the range of 57.7–98.2 µM. This new derivative, thus, selectively inhibits hCA II over the hCA I, IX, XII isoforms, which may be used for further understanding the physiological roles of some of these isoforms in various pathologies.
Whole-Genome Sequencing-Based Characteristics in Extended-Spectrum Beta-Lactamase-Producing Escherichia coli Isolated from Retail Meats in Korea
Authors: Kim Seokhwan , Kim Hansol , Kim Yonghoon , Kim Migyeong , Kwak Hyosun , Ryu Sangryeol
Published: April 2020

The spread of extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-EC) has posed a critical health risk to both humans and animals, because resistance to beta-lactam antibiotics makes treatment for commonly infectious diseases more complicated. In this study, we report the prevalence and genetic characteristics of ESBL-ECs isolated from retail meat samples in Korea. A total of 1205 E. coli strains were isolated from 3234 raw meat samples, purchased from nationwide retail stores between 2015 and 2018. Antimicrobial susceptibility testing was performed for all isolates by a broth microdilution method, and the ESBL phenotype was determined according to the Clinical and Laboratory Standards Institute (CLSI) confirmatory method. All ESBL-EC isolates (n = 29) were subjected to whole-genome sequencing (WGS). The antimicrobial resistance genes, plasmid incompatibility types, E. coli phylogroups, and phylogenetic relations were investigated based on the WGS data. The prevalence of ESBL-ECs in chicken was significantly higher than that in other meat samples. The results in this study demonstrate that clonally diverse ESBL-ECs with a multidrug resistance phenotype were distributed nationwide, although their prevalence from retail meat was 0.9%. The dissemination of ESBL-ECs from retail meat poses a potential risk to consumers and food-handlers, suggesting that the continuous surveillance of ESBL-ECs in retail meat should be conducted at the national level.
Optimization of Mesa Etch for a Quasi-Vertical GaN Schottky Barrier Diode (SBD) by Inductively Coupled Plasma (ICP) and Device Characteristics
Authors: Sun Yue , Kang Xuanwu , Zheng Yingkui , Wei Ke , Li Pengfei , Wang Wenbo , Liu Xinyu , Zhang Guoqi
Published: April 2020

The optimization of mesa etch for a quasi-vertical gallium nitride (GaN) Schottky barrier diode (SBD) by inductively coupled plasma (ICP) etching was comprehensively investigated in this work, including selection of the etching mask, ICP power, radio frequency (RF) power, ratio of mixed gas, flow rate, and chamber pressure, etc. In particular, the microtrench at the bottom corner of the mesa sidewall was eliminated by a combination of ICP dry etching and tetramethylammonium hydroxide (TMAH) wet treatment. Finally, a highly anisotropic profile of the mesa sidewall was realized by using the optimized etch recipe, and a quasi-vertical GaN SBD was demonstrated, achieving a low reverse current density of 10−8 A/cm2 at −10 V.
Photoexcitation Processes in Oligomethine Cyanine Dyes for Dye-Sensitized Solar Cells—Synthesis and Computational Study
Authors: Oprea Corneliu I. , Panait Petre , Essam Zahraa M. , Abd El-Aal Reda M. , Gîrțu Mihai A.
Published: April 2020

We report density functional theory (DFT) calculations of three newly synthesized oligomethine cyanine-based dyes as potential TiO2-sensitizers in dye-sensitized solar cells. The three dyes have π-symmetry and the same acceptor side, terminating in the carboxylic anchor, but they differ through the π-bridge and the donor groups. We perform DFT and time-dependent DFT studies and present the electronic structure and optical properties of the dyes alone as well as adsorbed to the TiO2 nanocluster, to provide some predictions on the photovoltaic performance of the system. We analyze theoretically the factors that can influence the short circuit current and the open circuit voltage of the dye-sensitized solar cells. We examine the matching of the absorption spectra of the dye and dye-nanocluster system with the solar irradiation spectrum. We display the energy level diagrams and discuss the alignment between the excited state of the dyes and the conduction band edge of the oxide as well as between the redox level of the electrolyte and the ground state of the dyes. We determine the electron density of the key molecular orbitals and analyze comparatively the electron transfer from the dye to the semiconducting substrate. To put our findings in the right perspective we compare the results of our calculations with those obtained for a coumarin-based dye used in fabricating and testing actual devices, for which experimental data regarding the photovoltaic performance are available.
Chemical- and Mechanical-Induced Lubrication Mechanisms during Hot Rolling of Titanium Alloys Using a Mixed Graphene-Incorporating Lubricant
Authors: Kong Ning , Zhang Jiaming , Zhang Jie , Li Hongbo , Wei Boyu , Li Dongshan , Zhu Hongtao
Published: April 2020

Hot rolling of titanium alloy currently is carried out without lubrication because of the surface defects. In order to explore an effective lubrication scheme to reduce friction and wear during hot rolling of titanium alloy, a mixed graphene-incorporating lubricant has been proposed to study its lubrication performance and mechanism. The tribological experiments were carried out by ball-disk friction and wear tester under hot-rolling parameters. Scanning electron microscopy (SEM), X-ray energy spectrum analyzer (EDS), X-ray powder diffractometer (XRD) and Raman analysis were used to analyse the surface and cross-section of the wear marks on the samples after the tribological experiments. The results show that the friction coefficient decreases up to about 35% compared with tests under dry and lubricated conditions. The surface quality of the wear marks is improved significantly after applying the proposed lubricant. The graphene which is embedded in the phosphate film can be effectively applied as a lubricating material to strengthen the lubricating film with less combustion loss at high temperatures. A chemical- and mechanical-induced lubrication mechanism for the hot rolling of titanium sheets has been proposed due to the synergistic lubrication effect of the graphene, ZrO2 nano particles and phosphate. It is of great significance and potential value to apply this proposed lubricant as an effective way to reduce the wear, friction and oxidation during the hot-rolling process of titanium alloy.
A General Protocol for Electrospun Non-Woven Fabrics of Dialdehyde Cellulose and Poly(Vinyl Alcohol)
Authors: Hell Slavica , Ohkawa Kousaku , Amer Hassan , Potthast Antje , Rosenau Thomas
Published: April 2020

In the past two decades, research on electrospinning has boomed due to its advantages of simple process, small fiber diameter, and special physical and chemical properties. The electrospun fibers are collected in a non-woven state in most cases (electrospun non-woven fabrics, ESNWs), which renders the electrospinning method an optimum approach for non-woven fabric manufacturing on the nano-scale. The present study establishes a convenient preparation procedure for converting water-soluble dialdehyde cellulose (DAC) into DAC-based electrospun non-woven fabrics (ESNWs) reinforced with poly(vinyl alcohol) (PVA). The aldehyde content, which was quantified by colorimetry using Schiff’s reagent, was 11.1 mmol per gram of DAC, which corresponds to a conversion yield of ca. 90%. DAC is fully water-soluble at room temperature between 10 and 30 wt%, and aqueous solutions turn into hydrogels within 24 h. To overcome gelation, NaHSO3, which forms bisulfite adducts with aldehyde functions, was added to the DAC and its concentration was optimized at 1 wt%. The electrospun (ES) dope containing 5 wt% DAC, 5 wt% PVA, and 1 wt% NaHSO3 in an aqueous solution was successfully transformed into ESNW, with an average fiber diameter of 345 ± 43 nm. Post-spinning treatment with excess hexamethylene diisocyanate was performed to insolubilize the ESNW materials. The occurrence of this chemical conversion was confirmed by energy-dispersive X-ray elemental analysis and vibrational spectra. The cross-linked DAC/PVA ESNW retained its thin fiber network upon soaking in distilled water, increasing the average fiber diameter to 424 ± 95 nm. This suggests that DAC/PVA-ESNWs will be applicable for incorporation or immobilization of biologically active substances.
Erythropoiesis and Red Cell Indices Undergo Adjustments during Pregnancy in Response to Maternal Body Size but not Inflammation
Authors: Vega-Sánchez Rodrigo , Tolentino-Dolores Mari Cruz , Cerezo-Rodríguez Blanca , Chehaibar-Besil Georgette , Flores-Quijano María Eugenia
Published: April 2020

During human pregnancy, iron requirements gradually increase, leading to higher amounts of erythropoietin (EPO) and reticulocytes, and changes in erythrocyte size and density. Women with pregestational obesity experience “obesity hypoferremia” during pregnancy, which alters iron homeostasis. In this study we aimed to describe the relationship between EPO and iron nutrition status during nonanemic pregnancy, and to explore whether obesity and inflammation influence erythropoiesis and red cell indices. We conducted a secondary analysis of a cohort followed throughout pregnancy. Participants were nonanemic women assigned to two study groups based on pregestational body mass index (pgBMI): adequate weight (AW, n = 53) or obesity (Ob, n = 40). All received a multivitamin supplement. At gestational ages (GA) 13, 21, 28 and 34, we measured hemoglobin and red cell indices with an ACT-5DIFF hematology counter, and reticulocyte percentage by manual cell counting. EPO, interleukin (IL–6) and markers of iron status, i.e., hepcidin, serum transferrin receptor (sTfr) and ferritin, were measured by ELISA. Bivariate correlations showed that EPO was positively associated with pgBMI, GA, sTfr and IL-6, but negatively associated with hepcidin, ferritin and hemoglobin, and unrelated to iron intake. Generalized linear models adjusted for confounding factors showed that EPO and erythrocyte concentrations were significantly higher in women in the Ob group, while mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH) and red cell distribution width (RDW) were lower; reticulocytes and mean corpuscular hemoglobin concentration (MCHC) were not different. Differences were not altered when controlling for inflammation (IL–6). These changes suggest that, in addition to altering iron metabolism, a larger maternal body size during pregnancy results in higher erythropoiesis without increasing hemoglobin, which is exhibited in the latter being distributed among more and smaller erythrocytes.
Elevation of the Blood Glucose Level is Involved in an Increase in Expression of Sweet Taste Receptors in Taste Buds of Rat Circumvallate Papillae
Authors: Iwamura Moemi , Honda Risa , Nagasawa Kazuki
Published: April 2020

The gustation system for sweeteners is well-known to be regulated by nutritional and metabolic conditions, but there is no or little information on the underlying mechanism. Here, we examined whether elevation of the blood glucose level was involved in alteration of the expression of sweet taste receptors in circumvallate papillae (CP) and sweet taste sensitivity in male Sprague-Dawley rats. Rats under 4 h-fed conditions following 18 h-fasting exhibited elevated blood glucose levels and decreased pancreatic T1R3 expression, compared to rats after 18 h-fasting treatment, and they exhibited increased protein expression of sweet taste receptors T1R2 and T1R3 in CP. Under streptozotocin (STZ)-induced diabetes mellites (DM) conditions, the protein expression levels of T1R2 and T1R3 in CP were higher than those under control conditions, and these DM rats exhibited increased lick ratios in a low sucrose concentration range in a brief access test with a mixture of sucrose and quinine hydrochloride (QHCl). These findings indicate that the elevation of blood glucose level is a regulator for an increase in sweet taste receptor protein expression in rat CP, and such alteration in STZ-induced DM rats is involved in enhancement of their sweet taste sensitivity.
Inventory and Evolution of Mitochondrion-localized Family A DNA Polymerases in Euglenozoa
Authors: Harada Ryo , Hirakawa Yoshihisa , Yabuki Akinori , Kashiyama Yuichiro , Maruyama Moe , Onuma Ryo , Soukal Petr , Miyagishima Shinya , Hampl Vladimír , Tanifuji Goro , Inagaki Yuji
Published: April 2020

The order Trypanosomatida has been well studied due to its pathogenicity and the unique biology of the mitochondrion. In Trypanosoma brucei, four DNA polymerases, namely PolIA, PolIB, PolIC, and PolID, related to bacterial DNA polymerase I (PolI), were shown to be localized in mitochondria experimentally. These mitochondrion-localized DNA polymerases are phylogenetically distinct from other family A DNA polymerases, such as bacterial PolI, DNA polymerase gamma (Polγ) in human and yeasts, “plant and protist organellar DNA polymerase (POP)” in diverse eukaryotes. However, the diversity of mitochondrion-localized DNA polymerases in Euglenozoa other than Trypanosomatida is poorly understood. In this study, we discovered putative mitochondrion-localized DNA polymerases in broad members of three major classes of Euglenozoa—Kinetoplastea, Diplonemea, and Euglenida—to explore the origin and evolution of trypanosomatid PolIA-D. We unveiled distinct inventories of mitochondrion-localized DNA polymerases in the three classes: (1) PolIA is ubiquitous across the three euglenozoan classes, (2) PolIB, C, and D are restricted in kinetoplastids, (3) new types of mitochondrion-localized DNA polymerases were identified in a prokinetoplastid and diplonemids, and (4) evolutionarily distinct types of POP were found in euglenids. We finally propose scenarios to explain the inventories of mitochondrion-localized DNA polymerases in Kinetoplastea, Diplonemea, and Euglenida.
The Treatment of Impaired Wound Healing in Diabetes: Looking among Old Drugs
Authors: Spampinato Simona Federica , Caruso Grazia Ilaria , De Pasquale Rocco , Sortino Maria Angela , Merlo Sara
Published: April 2020

Chronic wounds often occur in patients with diabetes mellitus due to the impairment of wound healing. This has negative consequences for both the patient and the medical system and considering the growing prevalence of diabetes, it will be a significant medical, social, and economic burden in the near future. Hence, the need for therapeutic alternatives to the current available treatments that, although various, do not guarantee a rapid and definite reparative process, appears necessary. We here analyzed current treatments for wound healing, but mainly focused the attention on few classes of drugs that are already in the market with different indications, but that have shown in preclinical and few clinical trials the potentiality to be used in the treatment of impaired wound healing. In particular, repurposing of the antiglycemic agents dipeptidylpeptidase 4 (DPP4) inhibitors and metformin, but also, statins and phenyotin have been analyzed. All show encouraging results in the treatment of chronic wounds, but additional, well designed studies are needed to allow these drugs access to the clinics in the therapy of impaired wound healing.
Hydrothermal Carbonization and Pellet Production from Egeria densa and Lemna minor
Authors: Álvarez Xana , Cancela Ángeles , Freitas Vanesa , Valero Enrique , Sánchez Ángel , Acuña-Alonso Carolina
Published: April 2020

Biofuels are seen as a potential option for mitigating the effects of fossil fuel use. On the other hand, nutrient pollution is accelerating eutrophication rates in rivers, lakes, and coastal waters. Harvesting aquatic plants to produce biofuels could mitigate this problem, though it is important to attack the problem at source, mainly as regards the contribution of nutrients. For the first time, solid biofuels were obtained in the forms of carbon and pellets from the aquatic plants Egeria densa, which is classed as an invasive plant under the Spanish Catalogue of Exotic Invasive Species, and Lemna minor, both of which can be found in the Umia River in north-west Spain. The essential oils and macro- and microelements present in both these plants were also extracted and analyzed. The higher heating values (HHVs) of the carbon products obtained ranged from 14.28 to 17.25 MJ/kg. The ash content ranged from 22.69% to 49.57%. The maximum yield obtained for biochar for Egeria densa at 200 °C was 66.89%. Temperature significantly affects solid hydrochar yield. The HHVs of the pellets obtained ranged from 11.38 to 13.49 MJ/kg. The use of these species to obtain biofuels through hydrothermal carbonization (HTC) and pellets is a novel and effective approach that will facilitate the removal of nutrients that cause eutrophication in the Umia River. The elements extracted show that harvesting these plants will help to remove excessive nutrients from the ecosystem.
Exogenous Ascorbic Acid Induced Chilling Tolerance in Tomato Plants Through Modulating Metabolism, Osmolytes, Antioxidants, and Transcriptional Regulation of Catalase and Heat Shock Proteins
Authors: Elkelish Amr , Qari Sameer H. , Mazrou Yasser S. A. , Abdelaal Khaled A. A. , Hafez Yaser M. , Abu-Elsaoud Abdelghafar M. , Batiha Gaber El-Saber , El-Esawi Mohamed A. , El Nahhas Nihal
Published: April 2020

Chilling, a sort of cold stress, is a typical abiotic ecological stress that impacts the development as well as the growth of crops. The present study was carried to investigate the role of ascorbic acid root priming in enhancing tolerance of tomato seedlings against acute chilling stress. The treatments included untreated control, ascorbic acid-treated plants (AsA; 0.5 mM), acute chilling-stressed plants (4 °C), and chilling stressed seedlings treated by ascorbic acid. Exposure to acute chilling stress reduced growth in terms of length, fresh and dry biomass, pigment synthesis, and photosynthesis. AsA was effective in mitigating the injurious effects of chilling stress to significant levels when supplied at 0.5 mM concentrations. AsA priming reduced the chilling mediated oxidative damage by lowering the electrolyte leakage, lipid peroxidation, and hydrogen peroxide. Moreover, up regulating the activity of enzymatic components of the antioxidant system. Further, 0.5 mM AsA proved beneficial in enhancing ions uptake in normal and chilling stressed seedlings. At the gene expression level, AsA significantly lowered the expression level of CAT and heat shock protein genes. Therefore, we theorize that the implementation of exogenous AsA treatment reduced the negative effects of severe chilling stress on tomato.
The Influence of Local Habitat and Microclimate on the Levels of Secondary Metabolites in Slovak Bilberry (Vaccinium myrtillus L.) Fruits
Authors: Vaneková Zuzana , Vanek Miroslav , Škvarenina Jaroslav , Nagy Milan
Published: April 2020

The berries of Vaccinium myrtillus L. are usually collected in the wild for the purpose of being a food source. They are naturally high in phenolic compounds, which possess antioxidative properties, so the berries are therefore often labeled as “functional foods”. This study evaluated seven samples of bilberry fruits from different locations in Slovakia for the content of the main phenolic compounds (anthocyanins, flavonoids and tannins) using European Pharmacopoeia 9 spectrophotometric methods. A thorough analysis of environmental factors showed that several phenolic constituents are closely corresponding with their respective environments, as well as with each other. The environmental factors with statistically significant correlations in this study are altitude, habitat type, sunlight exposure, and soil carbon content. Our findings suggest that the berries collected at sunny sites with no topsoil damage contain more phenolic compounds. The lowest amounts of phenolic compounds were found in samples from dense forests or with visible soil erosion and windthrow damage. The negative effect of windthrow damage on the levels of secondary metabolites in bilberry fruits has been described for the first time. This study observed no relationship between the amount of phenolic compounds and soil pH, soil nitrogen levels, or slope exposition.
Interactive Effects of the Potassium and Nitrogen Relationship on Yield and Quality of Strawberry Grown Under Soilless Conditions
Authors: Preciado-Rangel Pablo , Troyo-Diéguez Enrique , Valdez-Aguilar Luis Alonso , García-Hernández José Luis , Luna-Ortega José Guadalupe
Published: April 2020

K and N are the nutrients with the highest influence on yield and fruit quality. From this perspective, the aim of this study was to determine the effect of N as NO3−, K+ and their interactions on the yield and quality of strawberries grown under soilless conditions. A solution comprised of micronutrients based on an amended Steiner’s Universal Nutrient Solution was mixed with 4 levels of K+ (5, 7, 9 and 11 mol m−3) and 3 levels of NO3− (9, 12, and 15 mol m−3) to obtain 12 treatments. The results suggest that 15 mol m−3 of NO3− in the nutrient solution produced the highest yield, but fruit with low nutraceutical quality. On the other hand, 11 mol m−3 of K+ in the nutrient solution produced the highest yield and fruit with the best nutraceutical quality. The ionic concentration of the Universal Steiner’s Nutrient Solution proved to be the best nutritional option to maximize the yield and nutraceutical quality of strawberry fruit. The increase in NO3− concentration in the nutrient solution produced a higher yield of strawberries, while a higher concentration of K+ improved fruit quality, thus reaffirming the significance of nutrients within the plant functioning of this crop.
Activity of Saponins from Medicago Species against Phytoparasitic Nematodes
Authors: D’Addabbo Trifone , Argentieri Maria Pia , Żuchowski Jerzy , Biazzi Elisa , Tava Aldo , Oleszek Wieslaw , Avato Pinarosa
Published: April 2020

Content of bioactive saponins of Medicago species suggests that they may also exert, as previously demonstrated on M. sativa, nematicidal properties exploitable for the formulation of new products for sustainable phytoparasitic nematode management. This study was addressed to highlight the bioactivity of saponins from five different Medicago species still poorly known for their biological efficacy, i.e., M. heyniana, M. hybrida, M. lupulina, M. murex and M. truncatula, against the plant parasitic nematodes Meloidogyne incognita, Xiphinema index and Globodera rostochiensis. The bioactivity of the extracts from the five Medicago species was assessed by in vitro assays on the juveniles (J2) and eggs of M. incognita and G. rostochiensis and the adult females of X. index. The suppressiveness to M. incognita of soil treatments with the Medicago plant biomasses was also investigated in a tomato experiment. The nematicidal activity of the five Medicago species was reported and discussed in relation to their phytochemical profile.
Transcriptomic Response to Water Deficit Reveals a Crucial Role of Phosphate Acquisition in a Drought-Tolerant Common Bean Landrace
Authors: López Cristina María , Pineda Manuel , Alamillo Josefa M
Published: April 2020

Drought is one of the most critical factors limiting legume crop productivity. Understanding the molecular mechanisms of drought tolerance in the common bean is required to improve the yields of this important crop under adverse conditions. In this work, RNA-seq analysis was performed to compare the transcriptome profiles of drought-stressed and well-irrigated plants of a previously characterized drought-tolerant common bean landrace. The analysis revealed responses related with the abscisic acid signaling, including downregulation of a phosphatase 2C (PP2C) and an abscisic acid-8′ hydroxylase, and upregulation of several key transcription factors and genes involved in cell wall remodeling, synthesis of osmoprotectants, protection of photosynthetic apparatus, and downregulation of genes involved in cell expansion. The results also highlighted a significant proportion of differentially expressed genes related to phosphate starvation response. In addition, the moderate detrimental effects of drought in the biomass of these tolerant plants were abolished by the addition of phosphate, thus indicating that, besides the ABA-mediated response, acquisition of phosphate could be crucial for the drought tolerance of this common bean genotype. These results provided information about the mechanisms involved in drought response of common bean response that could be useful for enhancing the drought tolerance of this important crop legume.
Progress and Challenges in Ex Situ Conservation of Forage Germplasm: Grasses, Herbaceous Legumes and Fodder Trees
Authors: Hanson Jean , Ellis Richard
Published: April 2020

Forages provide an important livestock feed resource globally, particularly for millions of smallholder farmers, and have important roles in natural resource management and carbon sequestration, reducing soil erosion and mitigating the effects of climate change. Forage germplasm remains the basis for the selection and development of new, higher-yielding and better adaptedgenotypes to meet the increasing demand for livestock feed. Rapid rates of genetic erosion of forage diversity due to land-use change from natural pastures and rangelands to crop production to meet the food security requirements of a growing global population, together with pressures from a changing climate, highlight the necessity for ex situ seed conservation of forage genetic resources to provide germplasm for use by future generations. Whilst many forage species have orthodox seeds, the diverse range of genera and species which provide forage is a challenge in terms of the wide scope of information and understanding on conservation methods that genebank managers require—particularly for tropical forages, many of which are comparatively under-researched. We review the challenges to the conservation of tropical forage species by seed in ex situ genebanks and provide information on optimum methods for their management.
Study of the Effect of Methyldiethanolamine Initiator on the Recording Properties of Acrylamide Based Photopolymer
Authors: Rogers Brian , Martin Suzanne , Naydenova Izabela
Published: April 2020

The use of Holographic Optical Elements (HOEs) in applications, such as in light shaping and redirection, requires certain characteristics such as a high Diffraction Efficiency, low angular selectivity and stability against UV damage. In order to maximize the performance of the HOEs, photosensitive materials are needed that have been optimised for the characteristics that are of particular importance in that application. At the core of the performance of these devices is the refractive index modulation created during holographic recording. Typically, a higher refractive index modulation will enable greater light Diffraction Efficiency and also operation with thinner devices, which in turn decreases the angular selectivity and the stability of the refractive index modulation introduced during recording, which is key to the longevity of the device. Solar concentrators based on volume HOEs can particularly benefit from thinner devices, because, for a solar concentrator to have a high angular working range, thinner photopolymer layers with a smaller angular selectivity are required. This paper presents an optimisation of an acrylamide-based photopolymer formulation for an improved refractive index modulation and recording speed. This was achieved by studying the effect of the concentration of acrylamide and the influence of different initiators in the photopolymer composition on the diffraction efficiency of holographic gratings. Two initiators of different molecular weights were compared: triethanolamine (TEA) and methyldiethanolamine (MDEA). A fivefold increase in the rate of grating formation was achieved through the modification of the acrylamide concentration alone, and it was also found that holograms recorded with MDEA as the initiator performed the best and recorded up to 25% faster than a TEA-based photopolymer. Finally, tests were carried out on the stability of the protected and unprotected photopolymer layers when subjected to UV light. The properties exhibited by this photopolymer composition make it a promising material for the production of optical elements and suitable for use in applications requiring prolonged exposure to UV light when protected by a thin melinex cover.
Tungsten-Doped Zinc Oxide and Indium–Zinc Oxide Films as High-Performance Electron-Transport Layers in N–I–P Perovskite Solar Cells
Authors: Kang Ju Hwan , Song Aeran , Park Yu Jung , Seo Jung Hwa , Walker Bright , Chung Kwun-Bum
Published: April 2020

Perovskite solar cells (PSCs) have attracted tremendous research attention due to their potential as a next-generation photovoltaic cell. Transition metal oxides in N–I–P structures have been widely used as electron-transporting materials but the need for a high-temperature sintering step is incompatible with flexible substrate materials and perovskite materials which cannot withstand elevated temperatures. In this work, novel metal oxides prepared by sputtering deposition were investigated as electron-transport layers in planar PSCs with the N–I–P structure. The incorporation of tungsten in the oxide layer led to a power conversion efficiency (PCE) increase from 8.23% to 16.05% due to the enhanced electron transfer and reduced back-recombination. Scanning electron microscope (SEM) images reveal that relatively large grain sizes in the perovskite phase with small grain boundaries were formed when the perovskite was deposited on tungsten-doped films. This study demonstrates that novel metal oxides can be used as in perovskite devices as electron transfer layers to improve the efficiency.
Versatile Polypropylene Copolymers from a Pilot-Scale Spheripol II Process
Authors: Wang Xiong , Xu Renwei , Kang Wenqian , Fan Jie , Han Xiaoyu , Xu Yunbo
Published: April 2020

Polypropylene (PP) is one of the most widely used polymers. In this paper, three types of PPs including random PP, impact PP, and impact PP with high clarity, were prepared through a 75 kg/h pilot-scale Spheripol II process. The three produced PPs were produced by the selection or combination the two loops and gas phase reactor and controlling the comonomer and hydrogen concentrations. The three prepared PPs then were pelleted with the clarified nucleating agent NX 8000 and tested for mechanical, thermal, and optical properties. Their molecular structures and rubber phase size were also investigated by GPC, 13C NMR, temperature rising elution fractionation (TREF), XRD, SEM analysis, etc. The results showed that the random PP (PP-1) and the impact PP with high clarity (PP-3) obtained excellent optical transparency with a haze of 12.5% and 13.5% due to their small rubber phase size (roughly ≤ 100 nm), while the impact PP (PP-2) obtained bad transparency with a haze of 98.8% due to the large rubber phase size (about 1 μm) caused by the poor thermal compatibility with the PP matrix. The rubber phase content and ethylene/propylene sequence distributions of the three PPs varied much and resulted in different impact strengths and stiffness properties. PP-2 had a high impact strength of 14.5 kJ/m2 due to the rubber phase generated in the gas phase reactor. Except for the optical transparency, PP-3 gained stiffness and toughness, with 914 MPa of flexural modulus and 25.1 kJ/m2 of impact strength due to the unique molecular structure of its rubber phase.
Poly (Ethylene Oxide)-Based Block Copolymer Electrolytes Formed via Ligand-Free Iron-Mediated Atom Transfer Radical Polymerization
Authors: Li Sibo , Tian Mengying , Wang Jirong , Du Feipeng , Li Liang , Xue Zhigang
Published: April 2020

The Br-terminated poly (ethylene oxide) (PEO-Br) is used as a green and efficient macroinitiator in bulk Fe-catalyzed atom transfer radical polymerization (ATRP) without the addition of any organic ligands. The polymerization rate is able to be mediated by PEO-Br with various molecular weights, and the decrease in redox potential of FeBr2 in cyclic voltammetry (CV) curves indicates that an increased coordination effect is deteriorated with the depressing reaction activity in the longer ethylene oxide (EO) chain in PEO-Br. In combination with the study of different catalysts and catalytic contents, the methyl metharylate (MMA) or poly (ethylene glycol) monomethacrylate (PEGMA) was successfully polymerized with PEO-Br as an initiator. This copolymer obtained from PEGMA polymerization can be further employed as a polymer matrix to form the polymer electrolyte (PE). The higher ionic conductivity of PE was obtained by using a high molecular weight of copolymer.
Theory of Flexible Polymer Networks: Elasticity and Heterogeneities
Authors: Panyukov Sergey
Published: April 2020

A review of the main elasticity models of flexible polymer networks is presented. Classical models of phantom networks suggest that the networks have a tree-like structure. The conformations of their strands are described by the model of a combined chain, which consists of the network strand and two virtual chains attached to its ends. The distribution of lengths of virtual chains in real polydisperse networks is calculated using the results of the presented replica model of polymer networks. This model describes actual networks having strongly overlapping and interconnected loops of finite sizes. The conformations of their strands are characterized by the generalized combined chain model. The model of a sliding tube is represented, which describes the general anisotropic deformations of an entangled network in the melt. I propose a generalization of this model to describe the crossover between the entangled and phantom regimes of a swollen network. The obtained dependence of the Mooney-Rivlin parameters C 1 and C 2 on the polymer volume fraction is in agreement with experiments. The main results of the theory of heterogeneities in polymer networks are also discussed.
Enhancing Mixing and Thermal Management of Recycled Carbon Composite Systems by Torsion-Induced Phase-to-Phase Thermal and Molecular Mobility
Authors: Jian Ranran , Shi Zhonghe , Liu Haichao , Yang Weimin , Sain Mohini
Published: April 2020

A novel torsion screw has been proposed to resolve the inadequate control of mass transfer and the thermal management of two component polymer blends and their carbon fiber composites. The novel torsional screw distinctly introduced radial flow in the torsion screw channel, which is a significant improvement over the flow pattern developed by the conventional screw. The heat transfer and mixing behavior of melt mixtures are enhanced by adapting screws with torsion elements compared with the traditional screw elements. Heat transfer efficacy in the polypropylene–polystyrene bi-phasic extrusion process improved with the increase in torsion element numbers. An increased number of newly designed torsional elements also improved the dispersion of minor phase in bi-phase polypropylene–polystyrene composition and their carbon fiber composites. The unique flow pattern induced by the torsion elements shows a synergistic effect on the melt-phase mass flow and the thermal flow field facilitating phase-to-phase thermal and molecular mobility and enhanced fiber orientation, crystallinity and mechanical properties of composite made from recycled carbon fiber/polypropylene. Microtomographs of recycled carbon fiber demonstrated the extraordinary ability of a torsion screw element to orient carbon fiber in both axial and radial directions.
Synthesis of Novel Polymeric Acrylate-Based Flame Retardants Containing Two Phosphorus Groups in Different Chemical Environments and Their Influence on the Flammability of Poly (Lactic Acid)
Authors: Sag Jacob , Kukla Philipp , Goedderz Daniela , Roch Hendrik , Kabasci Stephan , Döring Manfred , Schönberger Frank
Published: April 2020

Novel polymeric acrylate-based flame retardants (FR 1–4) containing two phosphorus groups in different chemical environments were synthesized in three steps and characterized via nuclear magnetic resonance (NMR) spectroscopy, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and mass spectrometry (MS). Polylactic acid (PLA) formulations with the synthesized compounds were investigated to evaluate the efficiency of these flame retardants and their mode of action by using TGA, UL94, and cone calorimetry. In order to compare the results a flame retardant polyester containing only one phosphorus group (ItaP) was also investigated in PLA regarding its flame inhibiting effect. Since the fire behavior depends not only on the mode of action of the flame retardants but also strongly on physical phenomena like melt dripping, the flame retardants were also incorporated into PLA with higher viscosity. In the UL94 vertical burning test setup, 10% of the novel flame retardants (FR 1–4) is sufficient to reach a V-0 rating in both PLA types, while a loading of 15% of ItaP is not enough to reach the same classification. Despite their different structure, TGA and cone calorimetry results confirmed a gas phase mechanism mainly responsible for the highly efficient flame retardancy for all compounds. Finally, cone calorimetry tests of the flame retardant PLA with two heat fluxes showed different flame inhibiting efficiencies for different fire scenarios.