bluuebunny/crossref_metadata_2025 huggingface dataset:
Palladium/Carbon Nanofibers by Combining Atomic Layer Deposition and Electrospinning for Organic Pollutant Degradation
Authors: Najem Melissa , Nada Amr A. , Weber Matthieu , Sayegh Syreina , Razzouk Antonio , Salameh Chrystelle , Eid Cynthia , Bechelany Mikhael
Published: April 2020

As organic dyes are a major source of pollution, it is important to develop novel and efficient heterogeneous catalysts with high activity for their degradation. In this work, two innovative techniques, atomic layer deposition and electrospinning, were used to prepare palladium nanoparticles (Pd NPs) supported on carbon nanofibers (CNFs). The sample morphology was investigated using scanning and transmission electron microscopy. This showed the presence of nanofibers of several micrometers in length and with a mean diameter of 200 nm. Moreover, the size of the highly dispersed Pd NPs was about 7 nm. X-ray photoelectron spectroscopy visually validated the inclusion of metallic Pd. The prepared nano-catalysts were then used to reduce methyl orange (MO) in the presence of sodium borohydride (NaBH4). The Freundlich isotherm model was the most suitable model to explain the adsorption equilibrium for MO onto the Pd/CNF catalysts. Using 5 mL MO dye-solution (0.0305 mM) and 1 mL NaBH4 (0.026 mM), a 98.9% of catalytic activity was achieved in 240 min by 0.01 g of the prepared nano-catalysts Pd/C (0.016 M). Finally, no loss of catalytic activity was observed when such catalysts were used again. These results represent a promising avenue for the degradation of organic pollutants and for heterogeneous catalysis.
An Overview of Electric Machine Trends in Modern Electric Vehicles
Authors: Agamloh Emmanuel , von Jouanne Annette , Yokochi Alexandre
Published: April 2020

Electric machines are critical components of the drivetrains of electric vehicles. Over the past few years the majority of traction drive systems have converged toward containing some form of a permanent magnet machine. There is increasing tendency toward the improvement of power density and efficiency of traction machines, thereby giving rise to innovative designs and improvements of basic machine topologies and the emergence of new classes of machines. This paper provides an overview of present trends toward high specific power density machines for traction drive systems. The focus will be on current technology and the trends that are likely to be pursued in the near future to achieve the high specific power goals set for the industry. The paper discusses machines that are applied in both hybrid and battery electric drivetrains without distinction and does not discuss the associated power electronic inverters. Future electric machine trends that are likely to occur are also projected.
Almost Sure Convergence for the Maximum and Minimum of Normal Vector Sequences
Authors: Chen Zhicheng , Zhang Hongyun , Liu Xinsheng
Published: April 2020

In this paper, we prove the almost sure convergences for the maximum and minimum of nonstationary and stationary standardized normal vector sequences under some suitable conditions.
Asymptotic Results in Broken Stick Models: The Approach via Lorenz Curves
Authors: Zbăganu Gheorghiță
Published: April 2020

A stick of length 1 is broken at random into n smaller sticks. How much inequality does this procedure produce? What happens if, instead of breaking a stick, we break a square? What happens asymptotically? Which is the most egalitarian distribution of the smaller sticks (or rectangles)? Usually, when studying inequality, one uses a Lorenz curve. The more egalitarian a distribution, the closer the Lorenz curve is to the first diagonal of [ 0 , 1 ] 2 . This is why in the first section we study the space of Lorenz curves. What is the limit of a convergent sequence of Lorenz curves? We try to answer these questions, firstly, in the deterministic case and based on the results obtained there in the stochastic one.
P-Tensor Product for Group C*-Algebras
Authors: Li Yufang , Dong Zhe
Published: April 2020

In this paper, we introduce new tensor products ⊗ p ( 1 ≤ p ≤ + ∞ ) on C ℓ p * ( Γ ) ⊗ C ℓ p * ( Γ ) and ⊗ c 0 on C c 0 * ( Γ ) ⊗ C c 0 * ( Γ ) for any discrete group Γ . We obtain that for 1 ≤ p < + ∞ C ℓ p * ( Γ ) ⊗ m a x C ℓ p * ( Γ ) = C ℓ p * ( Γ ) ⊗ p C ℓ p * ( Γ ) if and only if Γ is amenable; C c 0 * ( Γ ) ⊗ m a x C c 0 * ( Γ ) = C c 0 * ( Γ ) ⊗ c 0 C c 0 * ( Γ ) if and only if Γ has Haagerup property. In particular, for the free group with two generators F 2 we show that C ℓ p * ( F 2 ) ⊗ p C ℓ p * ( F 2 ) ≇ C ℓ q * ( F 2 ) ⊗ q C ℓ q * ( F 2 ) for 2 ≤ q < p ≤ + ∞ .
Some Janowski Type Harmonic q-Starlike Functions Associated with Symmetrical Points
Authors: Arif Muhammad , Barkub Omar , Srivastava Hari , Abdullah Saleem , Khan Sher
Published: April 2020

The motive behind this article is to apply the notions of q-derivative by introducing some new families of harmonic functions associated with the symmetric circular region. We develop a new criterion for sense preserving and hence the univalency in terms of q-differential operator. The necessary and sufficient conditions are established for univalency for this newly defined class. We also discuss some other interesting properties such as distortion limits, convolution preserving, and convexity conditions. Further, by using sufficient inequality, we establish sharp bounds of the real parts of the ratios of harmonic functions to its sequences of partial sums. Some known consequences of the main results are also obtained by varying the parameters.
A Rational Approximation for the Complete Elliptic Integral of the First Kind
Authors: Yang Zhen-Hang , Tian Jing-Feng , Zhu Ya-Ru
Published: April 2020

Let K ( r ) be the complete elliptic integral of the first kind. We present an accurate rational lower approximation for K ( r ) . More precisely, we establish the inequality 2 π K ( r ) > 5 ( r ′ ) 2 + 126 r ′ + 61 61 ( r ′ ) 2 + 110 r ′ + 21 for r ∈ ( 0 , 1 ) , where r ′ = 1 − r 2 . The lower bound is sharp.
Krukenberg Tumor in Association with Ureteral Stenosis Due to Peritoneal Carcinomatosis from Pulmonary Adenocarcinoma: A Case Report
Authors: Balescu Irina , Bejinariu Nona , Slaniceanu Simona , Gongu Mircea , Masoud Brandusa , Lacau Smarandita , Tie George , Ciocirlan Maria , Bacalbasa Nicolae , Copaescu Catalin
Published: April 2020

Krukenberg tumors from pulmonary adenocarcinoma represent an extremely rare situation; only a few cases have been reported. The aim of this paper is to report an unusual such case in which almost complete dysphagia and ureteral stenosis occurred. The 62-year-old patient was initially investigated for dysphagia and weight loss. Computed tomography showed the presence of a thoracic mass compressing the esophagus in association with a few suspect pulmonary and peritoneal nodules, one of them invading the right ureter. A biopsy was performed laparoscopically on the peritoneal nodules. The right adnexa presented an atypical aspect; right adnexectomy was also found. The histopathological and immunohistochemical studies confirmed that the primitive origin was pulmonary adenocarcinoma. Although both peritoneal carcinomatosis and ovarian metastases from pulmonary adenocarcinoma represent a very uncommon situation, this pathology should not be excluded, especially in cases presenting suspect pulmonary lesions.
Three-Dimensional Ankle Exercise with Combined Isotonic Technique for an Obese Subject with Plantar Fasciitis: A Case Study
Authors: Lee Kyung-Sun , Park Du-Jin
Published: April 2020

Background and objectives: Obese people have many foot-related disorders and plantar fasciitis (PF) is the most common disorder among them. However, research on the role of therapeutic exercises in PF is lacking and there is no evidence to suggest its benefits. As such, a further insight into therapeutic exercises is needed within this group. This case study investigated the effect of three-dimensional (3D) ankle exercises using a combined isotonic (CI) technique on function and balance in an obese subject with PF. Material and methods: The subject in this study was a 28-year-old obese woman who was diagnosed with PF by an orthopedic surgeon. A 3D ankle exercise program was commenced three times a week for 15 min over 4 weeks. The evaluations were conducted at five intervals: pre-test, and at 1, 2, 3 and 4 weeks from the initiation of the intervention. The tests were conducted in the following order: the patient-specific functional scale test (PSFS), an ultrasound of the plantar fascia, the heel pressure and balance test, the pressure pain threshold (PPT), and the 4-way ankle strength test. Results: The mean score of the PSFS test reduced by 70.55% after 4 weeks of the intervention. The thickness of the plantar fascia and heel pressure measured during single-leg standing decreased by 6.67% and 10.37%, respectively, after 4 weeks of the intervention. The anteroposterior and medial-lateral balance ability showed improvements of 8.29% and 8.61%, respectively, after 4 weeks of the intervention. The PPT improved by 38.01% after 4 weeks of the intervention. In the 4-way ankle strength test, dorsiflexion, plantar flexion, inversion, and eversion increased by 14.46%, 9.63%, 4.3% and 13.25%, respectively, after 4 weeks of the intervention. Conclusion: 3D ankle exercises utilizing the CI technique were shown to be effective in improving foot function, pressure pain, and muscle strength in dorsiflexion and inversion in an obese patient with PF.
Advances and Challenges in European Paediatric Palliative Care
Authors: Fraser Lorna K , Bluebond-Langner Myra , Ling Julie
Published: April 2020

Advances in both public health and medical interventions have resulted in a reduction in childhood mortality worldwide over the last few decades; however, children still have life-threatening conditions that require palliative care. Children’s palliative care is a specialty that differs from palliative care for adults in many ways. This paper discusses some of the challenges, and some of the recent advances in paediatric palliative care. Developing responsive services requires good epidemiological data, as well as a clarity on services currently available and a robust definition of the group of children who would benefit from palliative care. Once a child is diagnosed with a life-limiting condition or life-limiting illness, parents face a number of complex and difficult decisions; not only about care and treatment, but also about the place of care and ultimately, place of death. The best way to address the needs of children requiring palliative care and their families is complex and requires further research and the routine collection of high-quality data. Although research in children’s palliative care has dramatically increased, there is still a dearth of evidence on key components of palliative care notably decision making, communication and pain and symptom management specifically as it relates to children. This evidence is required in order to ensure that the care that these children and their families require is delivered.
The Effect of Emulsifiers on the Emulsion Stability and Extraction Efficiency of Cr(VI) Using Emulsion Liquid Membranes (ELMs) Formulated with a Green Solvent
Authors: Anarakdim Katia , Gutiérrez Gemma , Cambiella Ángel , Senhadji-Kebiche Ounissa , Matos María
Published: April 2020

The stability of emulsion liquid membranes (ELMs) and their ability to extract Cr(VI) were investigated. The objective of this study is to compare different ELM formulations using combinations of two hydrophilic (Tween 20 and Tween 80) and two lipophilic (polyglycerol polyricinoleate (PGPR) and Span 80) emulsifiers. TOPO (tri-n-octylphosphine oxide) as a carrier and a green solvent (sunflower oil) were used to provide high extraction efficiency of Cr(VI). All these double emulsions were characterized in droplet size distribution, zeta potential, visual inspection with a microscope, and stability. The best formulation was obtained with PGPR as the inner stabilizer and Tween 80 as the outer stabilizer, leading to Cr(VI) ion removal efficiency of up to 96%.
An Alternative Process for Leaching Chalcopyrite Concentrate in Nitrate-Acid-Seawater Media with Oxidant Recovery
Authors: Castellón César I. , Hernández Pía C. , Velásquez-Yévenes Lilian , Taboada María E.
Published: April 2020

An alternative copper concentrate leaching process using sodium nitrate and sulfuric acid diluted in seawater followed by gas scrubbing to recover the sodium nitrate has been evaluated. The work involved leaching test carried out under various condition by varying temperature, leaching time, particle size, and concentrations of NaNO3 and H2SO4. The amount of copper extracted from the chalcopyrite concentrate leached with seawater, 0.5 M of H2SO4 and 0.5 M of NaNO3 increased from 78% at room temperature to 91% at 45 °C in 96 h and 46 h of leaching, respectively. Gas scrubbing with the alkaline solution of NaOH was explored to recover part of the sodium nitrate. The dissolved salts were recovered by evaporation as sodium nitrate and sodium nitrite crystals.
Formation Process of the Integrated Core(Fe-6.5wt.%Si)@Shell(SiO2) Structure Obtained via Fluidized Bed Chemical Vapor Deposition
Authors: Wu Zhaoyang , Xian Chen , Jia Jixiang , Liao Xiangwei , Kong Hui , Xu Kun
Published: April 2020

As electromagnetic functional materials, soft magnetic composites (SMCs) have great potential for applications in high-energy electromagnetic conversion devices. The most effective way to optimize the performance of an SMC is to incorporate it into insulated ferromagnetic core-shell particles with high structural uniformity and integrity. Fluidized bed chemical vapor deposition (FBCVD) is a facile and efficient technique for the synthesis of ferromagnetic/SiO2 core-shell particles. However, the formation mechanism and conditions of integrated ferromagnetic/SiO2 core-shell structures during the FBCVD process are not fully understood. On this basis, the formation process and the deposition time required for transformation of the Fe-6.5wt.%Si substrate into the Fe-6.5wt.%Si/SiO2 composite, and finally into the Fe-6.5wt.%Si/SiO2 core-shell structure, were investigated. Deposition of the insulative SiO2 coating onto the Fe-6.5wt.%Si particles was described by the three-dimensional island nucleation theory. The SiO2 islands were initially concentrated in rough areas on the Fe-6.5wt.%Si particle substrates owing to the lower heterogeneous nucleation energy. Deposition for at least 960 s was necessary to obtain the integrated ferromagnetic/SiO2 core-shell structure. The uniformity, integrity, and thickness of the insulative SiO2 coating increased with the increasing deposition time. The results in this study may provide a foundation for future kinetics investigations and the application of FBCVD technology.
In-Situ Observation of Lüders Band Formation in Hot-Rolled Steel via Digital Image Correlation
Authors: Qiu Hai , Inoue Tadanobu , Ueji Rintaro
Published: April 2020

Although the Lüders yield phenomenon has been investigated for more than 150 years, some understanding of Lüders band formation lack substantial support from experimental evidence. In-situ observation of Lüders band formation in hot-rolled steel experimentally clarified the following facts: (i) When stress reaches the true upper yield stress, the Lüders band begins to nucleate. True upper yield stress is greater than nominal upper yield stress. (ii) Gross stress concentration promotes the Lüders band formation, and the size of the gross stress concentration region determines the initial width of the Lüders band. (iii) The Lüders band nucleates far ahead of the gross yield point.
Recovery of Lead and Zinc from Zinc Plant Leach Residues by Concurrent Dissolution-Cementation Using Zero-Valent Aluminum in Chloride Medium
Authors: Silwamba Marthias , Ito Mayumi , Hiroyoshi Naoki , Tabelin Carlito Baltazar , Hashizume Ryota , Fukushima Tomoki , Park Ilhwan , Jeon Sanghee , Igarashi Toshifumi , Sato Tsutomu , Chirwa Meki , Banda Kawawa , Nyambe Imasiku , Nakata Hokuto , Nakayama Shouta , Ishizuka Mayumi
Published: April 2020

Zinc plant leach residues (ZPLRs) contain significant amounts of metal compounds of lead (Pb), zinc (Zn), iron (Fe), etc., hence, they are considered as a secondary source of metals. On the other hand, ZPLRs are regarded as hazardous materials because they contain heavy metals that pollute the environment. Resources and environmental concerns of ZPLRs were addressed in this study by removing/recovering Pb and Zn using a concurrent dissolution and cementation technique. To cement the dissolved Pb and Zn in leaching pulp, zero-valent aluminum (ZVAl) was added during ZPLRs leaching in the hydrochloric (HCl)–sodium chloride (NaCl) solution. The resulting cemented metals were agglomerated and separated by sieving. Lead removal increased with increasing both NaCl and HCl concentrations. However, when ZVAl was added, significant Pb removal was achieved at a low concentration. Zinc was not cemented out of the pulp using ZVAl and its recovery from ZPLRs was dependent on the HCl concentration only. By applying a concurrent dissolution and cementation technique, both Pb and Zn were removed using a low concentration of NaCl, and most importantly Pb—the most toxic metal in ZPLRs—was captured and separated before the solid-liquid separation, hence, eliminating the need for extensive washing of the generated residues to remove the inherent residual solution.
Remote Fibre Laser Welding of Advanced High Strength Martensitic Steel
Authors: Prijanovič Urban , Prijanovič Tonkovič Marica , Trdan Uroš , Pleterski Matej , Jezeršek Matija , Klobčar Damjan
Published: April 2020

The study presents the results of remote robotic laser welding of advanced high strength Docol® 1200 M martensitic steel. One mm thick samples were welded in a lap joint configuration using a special clamping system. Welding was done using a continuous-wave (CW) fibre laser with a constant welding power of 300 W and constant focus diameter Ø 1.8 mm. Welding was done using 12 different welding speeds in the range from 0.15 to 1 m/min, whereas the inclination angle was kept constant at 0°. The influence of various welding speeds and linear heat inputs during welding on microstructural changes were examined by the occurrence of acicular and allotriomorphic ferrite or martensite. Results revealed big influence of the clamping system on the accumulation of the laser beam energy, heat sink and consequently weld size and geometry, as well as its microstructure and joint strength. Tensile-shear strength, microstructure and hardness results confirmed laser power of 300 W and 0.6 m/min welding speed as the optimal parameters, at which a martensitic structure was obtained in the weld. The width of the heat affected zone (HAZ) in this case is 1100 μm.
Blister Formation in Film Insert Moulding
Authors: Wöhner Timo , Islam Aminul , Hansen Hans N. , Tosello Guido , Whiteside Ben R.
Published: April 2020

The formation of blister in the injection moulded parts, especially in the film insert moulded parts, is one of most significant causes of part rejection due to cosmetic requirements or functionality issues. The mechanism and physics of blister formation for molded parts are not well-understood by the state-of-the-art literature. The current paper increases the fundamental understanding of the causes for blister formation. In the experiment, a membrane strip of 5 mm in width was overmoulded with Polypropylene (PP), which formed a disc-shaped part with a diameter of 17.25 mm and a thickness of 500 µm. To investigate the influence of the processing parameters, a full factorial design of experiments (DoE) setup was conducted, including mould temperature (Tm), barrel temperature (Tb), injection speed (Vi) and packing pressure (Pp) as variables. The degree of blistering at the surface was characterized by the areal surface roughness parameters Spk and Smr1, measured with a confocal laser microscope. The measurements were taken on the 10 mm long section of the membrane surface in the centre of the moulded part across the entire width of the film. In addition, the film insert moulding (FIM)-process was simulated and the average shrinkage of the substrate material under the membrane was investigated. Eventually, a method and processing window could be defined that could produce blister-free parts.
Design and Investigation of Modern UWB-MIMO Antenna with Optimized Isolation
Authors: Irshad Khan Muhammad , Khattak Muhammad Irfan , Rahman Saeed Ur , Qazi Abdul Baseer , Telba Ahmad Abdeltawab , Sebak Abdelrazik
Published: April 2020

This paper proposes a compact, semi-circular shaped multiple input multiple output (MIMO) antenna design with high isolation and enhanced bandwidth for ultrawide band (UWB) applications. A decoupling stub is used for high isolation reaching up to −55 dB over the entire bandwidth. The proposed antenna is used for UWB as well as super wide band (SWB) applications. The overall size of the proposed antenna is 18 × 36 × 1.6   mm3. The | S 11 |   and voltage standing wave ratio (VSWR) of the proposed antenna are less than −10 dB and 2, respectively, in the range of 3–40 GHz. The total impedance bandwidth of the proposed design is 37 GHz. The VSWR, | S 11 | , | S 22 | , | S 21 | , | S 12 | , gain, envelope correlation coefficient (ECC), radiation pattern, and various other characteristic parameters are discussed in detail. The proposed antenna is optimized and simulated in a computer simulation technology (CST) studio, and printed on a FR4 substrate.
Insights into the Microbiological Safety of Wooden Cutting Boards Used for Meat Processing in Hong Kong’s Wet Markets: A Focus on Food-Contact Surfaces, Cross-Contamination and the Efficacy of Traditional Hygiene Practices
Authors: Sekoai Patrick T. , Feng Shiqi , Zhou Wenwen , Ngan Wing Y. , Pu Yang , Yao Yuan , Pan Jie , Habimana Olivier
Published: April 2020

Hong Kong’s wet markets play a crucial role in the country’s supply of safe, fresh meat to satisfy the dietary needs of its population. Whilst food safety regulations have been introduced over the past few years to maintain the microbial safety of foods sold from these wet markets, it remains unclear whether the hygiene maintenance that is performed on the wooden cutting boards used for meat-processing is effective. In fact, hygiene maintenance may often be overlooked, and hygiene standards may be insufficient. If so, this may lead to the spread of harmful pathogens through cross-contamination, thereby causing severe risks to public health. The aim of this study was to determine the level of microbial transfer between wooden cutting boards and swine meat of various qualities, using 16S metagenomic sequencing, strain identification and biofilm screening of isolated strains. The results established that: (a) the traditional hygiene practices used for cleaning wooden cutting boards in Hong Kong’s wet markets expose the surfaces to potentially harmful microorganisms; (b) the processing of microbially contaminated meat on cutting boards cleaned using traditional practices leads to cross-contamination; and (c) several potentially pathogenic microorganisms found on the cutting boards have good biofilm-forming abilities. These results reinforce the need to review the traditional methods used to clean wooden cutting boards after the processing of raw meat in Hong Kong’ wet markets so as to prevent cross-contamination events. The establishment of proper hygiene protocols may reduce the spread of disease-causing microorganisms (including antibiotic-resistant microorganisms) in food-processing environments.
Escherichia coli O157:H7 Curli Fimbriae Promotes Biofilm Formation, Epithelial Cell Invasion, and Persistence in Cattle
Authors: Sheng Haiqing , Xue Yansong , Zhao Wei , Hovde Carolyn J. , Minnich Scott A.
Published: April 2020

Escherichia coli O157:H7 (O157) is noninvasive and a weak biofilm producer; however, a subset of O157 are exceptions. O157 ATCC 43895 forms biofilms and invades epithelial cells. Tn5 mutagenesis identified a mutation responsible for both phenotypes. The insertion mapped within the curli csgB fimbriae locus. Screening of O157 strains for biofilm formation and cell invasion identified a bovine and a clinical isolate with those characteristics. A single base pair A to T transversion, intergenic to the curli divergent operons csgDEFG and csgBAC, was present only in biofilm-producing and invasive strains. Using site-directed mutagenesis, this single base change was introduced into two curli-negative/noninvasive O157 strains and modified strains to form biofilms, produce curli, and gain invasive capability. Transmission electron microscopy (EM) and immuno-EM confirmed curli fibers. EM of bovine epithelial cells (MAC-T) co-cultured with curli-expressing O157 showed intracellular bacteria. The role of curli in O157 persistence in cattle was examined by challenging cattle with curli-positive and -negative O157 and comparing carriage. The duration of bovine colonization with the O157 curli-negative mutant was shorter than its curli-positive isogenic parent. These findings definitively demonstrate that a single base pair stably confers biofilm formation, epithelial cell invasion, and persistence in cattle.
Changes in the Ultrastructure of Candida albicans Treated with Cationic Peptides
Authors: Grigor’eva Alina , Bardasheva Alevtina , Tupitsyna Anastasiya , Amirkhanov Nariman , Tikunova Nina , Pyshnyi Dmitrii , Kleshev Maksim , Ryabchikova Elena
Published: April 2020

Candida albicans is becoming increasingly harmful for humans, which determines the need for new effective antifungal preparations. Currently, when testing antifungals, various morphological methods are used, among which transmission electron microscopy (TEM) is not the leading one. In this work, we used TEM to study the submicroscopic changes in C. albicans cells induced by cationic peptides R9F2 and (KFF)3K. Studies were performed on C. albicans-34 strain from the Collection of EMTC of ICBFM SB RAS in logarithmic phase. R9F2 and (KFF)3K showed an antifungal effect (MIC 10 and 20 μM) and suppressed fungal hyphal growth. Semithin and ultrathin sections of fungal suspensions incubated with 10 μM of peptides were studied at regular intervals from 15 min to 24 h. The first target of both peptides was plasmalemma, and its “alignment” was the only common morphological manifestation of their effect. Other changes in the plasmalemma and alteration of the vacuole and cell wall ultrastructure distinctly differed in cells treated with R9F2 and (KFF)3K peptides. In general, our work has shown pronounced differences of the temporal and morphologic characteristics of the effect of peptides, evidently related to their physicochemical properties. The benefit of TEM studies of ultrathin sections for understanding the mechanisms of action of antifungal drugs is shown.
Mechanisms Underlying the Rhizosphere-To-Rhizoplane Enrichment of Cellvibrio Unveiled by Genome-Centric Metagenomics and Metatranscriptomics
Authors: Zhang Yunzeng , Xu Jin , Wang Entao , Wang Nian
Published: April 2020

Maintaining integrity of the plant cell walls is critical for plant health, however, our previous study showed that Cellvibrio, which is recognized by its robust ability to degrade plant cell walls, was enriched from the citrus rhizosphere to the rhizoplane (i.e., the root surface). Here we investigated the mechanisms underlying the rhizosphere-to-rhizoplane enrichment of Cellvibrio through genome-centric metagenomics and metatranscriptomics analyses. We recovered a near-complete metagenome-assembled genome representing a potentially novel species of Cellvibrio, herein designated Bin79, with genome size of 5.71 Mb across 11 scaffolds. Differential gene expression analysis demonstrated that plant cell wall degradation genes were repressed, whereas genes encoding chitin-degrading enzymes were induced in the rhizoplane compared with the rhizosphere. Enhanced expression of multi-drug efflux genes and iron acquisition- and storage-associated genes in the rhizoplane indicated mechanisms by which Bin79 competes with other microbes. In addition, genes involved in repelling plant immune responses were significantly activated in the rhizoplane. Comparative genomics analyses with five related Cellvibrio strains showed the importance of gene gain events for the rhizoplane adaptation of Bin79. Overall, this study characterizes a novel Cellvibrio strain and indicates the mechanisms involved in its adaptation to the rhizoplane from meta-omics data without cultivation.
Reduction in the Choking Phenomenon in Elite Diving Athletes Through Changes in Gut Microbiota Induced by Yogurt Containing Bifidobacterium animalis subsp. lactis BB-12: A Quasi Experimental Study
Authors: Dong Weizhong , Wang Ying , Liao Shuaixiong , Lai Minghang , Peng Li , Song Gang
Published: April 2020

Objective: The aims of this study are as follows: (1) to understand the relationship between gut microbiota and the choking phenomenon in diving athletes, and (2) to regulate the gut microbiota in diving athletes by drinking yogurt containing Bifidobacterium animalis subsp. lactis BB-12 and observe changes in the choking phenomenon in diving athletes. Methods: Experiment 1: A total of 20 diving athletes were tested in low- and high-pressure situations. Gut microbiota (n = 18) composition was then determined and differences in the gut microbiota composition among diving athletes who presented choking vs. no choking were identified. Experiment 2: A total of 16 divers who presented choking were divided into a high yogurt group (n = 6) and a low yogurt group (n = 10) for 15 days. Results: (1) The content of Veillonellaceae in divers who presented choking was significantly higher when compared to divers who did not present choking (p < 0.05). Bifidobacteriaceae (r = −0.52, p < 0.05) and Lactobacillaceae (r = −0.66, p < 0.05) were negatively correlated with the choking index. (2) During experiment 2, the average daily intake of the high yogurt group was 611.78 ± 94.94 mL and the average daily intake of the low yogurt group was 338 ± 71.45 mL and the abundance of Bifidobacteriaceae was significantly higher in the high yogurt group than in the low yogurt group. After the experiment, the choking index in the high yogurt group became significantly lower than that of the low yogurt group (z = −3.26, p < 0.001). Conclusion: The intake of yogurt containing B. animalis subsp. lactis can increase the abundance of Bifidobacteriaceae in elite diving athletes and their performance under high pressure. Hence, gut microbiota may affect the choking phenomenon in elite diving athletes.
Yeast–Yeast Interactions: Mechanisms, Methodologies and Impact on Composition
Authors: Bordet Fanny , Joran Alexis , Klein Géraldine , Roullier-Gall Chloé , Alexandre Hervé
Published: April 2020

During the winemaking process, alcoholic fermentation is carried out by a consortium of yeasts in which interactions occurs. The consequences of these interactions on the wine matrix have been widely described for several years with the aim of controlling the winemaking process as well as possible. In this review, we highlight the wide diversity of methodologies used to study these interactions, and their underlying mechanisms and consequences on the final wine composition and characteristics. The wide variety of matrix parameters, yeast couples, and culture conditions have led to contradictions between the results of the different studies considered. More recent aspects of modifications in the composition of the matrix are addressed through different approaches that have not been synthesized recently. Non-volatile and volatile metabolomics, as well as sensory analysis approaches are developed in this paper. The description of the matrix composition modification does not appear sufficient to explain interaction mechanisms, making it vital to take an integrated approach to draw definite conclusions on them.
Direct Acid Leaching of Sphalerite: An Approach Comparative and Kinetics Analysis
Authors: Picazo-Rodríguez Nallely G. , Soria-Aguilar Ma. de Jesus , Martínez-Luévanos Antonia , Almaguer-Guzmán Isaias , Chaidez-Félix Josue , Carrillo-Pedroza Francisco Raul
Published: April 2020

The present work reports the direct leaching of zinc from a sphalerite concentrate in acid media. Lab-scale and pilot-scale experiments were conducted in atmospheric-pressure and low-pressure reactors, respectively. Leaching of zinc and precipitation of iron was achieved in the same stage using different reagents like Fe3+, O2, O3, and Fe2+ (which is continuously oxidized in the leaching solution by H2O2 and O2). The highest percentage of zinc extraction (96%) was obtained in pilot-scale experiments using H2SO4, Fe2+, and O2. Experimental results were compared with those of other researchers to provide a better understanding of the factors influencing the dissolution of zinc. In the first instance, it was determined from analysis of variance that leaching time and the use of an oxidant agent (O2 or O3) were the most influential factors during the direct leaching of zinc from the sphalerite concentrate. Kinetic models were also evaluated to determine the rate-limiting step of the sphalerite leaching; it was concluded that the type of the sulfur layer formed in the residue (porous or non-porous) depends on the type of the oxidant used in the leaching media, which determines the dissolution kinetics of zinc.
Mineral Formation under the Influence of Mine Waters (The Kizel Coal Basin, Russia)
Authors: Menshikova Elena , Osovetsky Boris , Blinov Sergey , Belkin Pavel
Published: April 2020

The development of coal deposits is accompanied by negative environmental changes. In the territory of the Kizel coal basin (Perm Region, Russia), the problem of contamination of water sources by acid mine waters and runoff from rock dumps is particularly acute. Mine waters are acidic (pH 2–3), with high mineralization (up to 25 g/L) and significant content of sulfate ions, iron, aluminum, manganese, toxic trace elements (As, Co, Ni, Pb and Zn). They are formed as a result of the interaction of underground waters from flooded mines of the Kizel basin with coal and rocks of dumps with high sulfur content (15%). Uncontrolled inflow of mine water into rivers (about 22 million m3 annually) leads to significant amounts of iron and aluminum hydroxide precipitation. These precipitations are in active interaction with river water, polluting the rivers tens of kilometers downstream and are entering the Kama reservoir. Studies of alluvial precipitation can be considered as a method of control and predictors of technogenic water pollution. The mineral composition of river sediments was studied with the application of different methods, including studies of sand-gravel and silty-clayey sediments. The sandy-gravel grains in the bottom load are mainly composed by natural minerals and are represented by a significant number of particles of coal dumps, slags and magnetic spherules. The silty-clayey material, mixed with natural minerals, contains a significant number of amorphous phases with a predominance of iron-rich substances, which may actively concentrate toxic elements. The presence of jarosite, goethite, basaluminite, lepidorocite and copiapite in silty-clayey sediments are indicators of the influence of mine waters.
Effect of Mg(II) and Na(I) Doping on the Electronic Structure and Mechanical Properties of Kaolinite
Authors: Zhao Jian , Qin Xinzhan , Wang Jiamin , He Manchao
Published: April 2020

Because kaolinite has multiple defects, it is very important to study the effect of different doped cations on the electronic structure and mechanical properties of kaolinite (Al4Si4O18H8) from the microscopic point of view with the first-principle calculation method. The results exhibited that the doping of Mg(II) and Na(I) makes the ion bond and layer spacing of kaolinite crystal change, and the bond length of the chemical bond between the doped and O atom is positively related to the atomic radius of the doped cations. Compared with undoped kaolinite crystal, the band gap width of the Mg-doped and Na-doped kaolinite crystal was larger, but the typical insulator characteristics were still maintained. Compared with undoped kaolinite crystal, Mg-doped and Na-doped kaolinite crystal had more electron transfer to O, while the Mg–O bond and Na–O bond had more ionic bond properties and less covalent bond composition than the Al–O bond. Finally, the elastic properties of undoped, Mg-doped, and Na-doped kaolinite crystal were further analyzed by calculating the elastic constant matrix. The influence of doping Mg(II) and Na(I) on C11 and C22 was greater than that on C33, indicating that doping had a greater influence on the stiffness in the direction of the parallel crystal plane. The doping of Mg(II) and Na(I) weakened the rigidity of kaolinite crystal materials and improved the plasticity and ductility of the materials. The atom-scale information provided a basis for explaining the mechanical behavior of kaolinite and is expected to provide guidance for solving the deformation problems in soft rock roadways.
Improved Understanding of the Sulfidization Mechanism in Amine Flotation of Smithsonite: An XPS, AFM and UV–Vis DRS Study
Authors: Liu Ruizeng , Pei Bin , Liu Zhicheng , Wang Yunwei , Li Jialei , Liu Dianwen
Published: April 2020

Sulfidization is required in the amine flotation of smithsonite; however, the sulfidization mechanism of smithsonite is still not fully understood. In this work, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and UV–vis diffuse reflectance spectroscopy (UV–vis DRS) were used to characterize sulfidized and unsulfidized smithsonite. The XPS and UV–vis DRS analyses showed that smithsonite sulfidization is a transformation of ZnCO3 to ZnS on the smithsonite surfaces. However, this transformation is localized, resulting in the coexistence of ZnCO3 and ZnS or in the formation of ZnS island structures on the sulfidized smithsonite surfaces. AFM height imaging showed that sulfidization can substantially change the surface morphology of smithsonite; in addition, AFM phase imaging demonstrated that sulfidization occurs locally on the smithsonite surfaces. Based on our findings, it can be concluded that smithsonite sulfidization is clearly a heterogeneous solid–liquid reaction in which the solid product attaches at the surfaces of unreacted smithsonite. Smithsonite sulfidization involves heterogeneous nucleation and growth of ZnS nuclei. Moreover, the ZnS might nucleate and grow preferentially in the regions with high reactivity, which might account for the formation of ZnS island structures. In addition, sphalerite-structured ZnS is more likely to be the sulfidization product of smithsonite under flotation-relevantconditions, as also demonstrated by the results of our UV–vis DRS analyses. The results of this study can provide deeper insights into the sulfidization mechanism of smithsonite.
Mineralogical and Chemical Characteristics of Slags from the Pyrometallurgical Extraction of Zinc and Lead
Authors: Nowinska Katarzyna
Published: April 2020

The slags derived from the fire refining of lead bullion, differ distinctly in the mineral composition, which results from the fact that these slags are end products of a series of chemical reactions (of both reduction and oxidation). The most common phases included in the refining slags are sulphates and hydrated sulphates (anglesite, gypsum, ktenasite and namuvite), oxides and hydroxides (wustite and goethite), nitrates (gerhardtite) and silicates (kirschsteinite and willemite). The other phases are sulphides and hydrated sulphides (sphalerite and tochilinite), metals (metallic Pb) and glass. Among the mineral components of these slags can be distinguished—primary mineral constituents, phase constituents formed in the ISP process and lead refining, secondary mineral constituents, formed in the landfill. The slags contain, in chemical terms, mainly FeO, CuO and SO3, PbO, in smaller contents SiO2, Al2O3 and CaO, TiO2, MnO, MgO, K2O, P2O5. The mineralogical and chemical composition indicate that slags may be a potential source of metals recovery and pyrometallurgical processing of these wastes seems to be highly rational.
Oxone®-Mediated TEMPO-Oxidized Cellulose Nanomaterials form I and form II
Authors: Moore II John P , Dachavaram Soma Shekar , Bommagani Shobanbabu , Penthala Narsimha Reddy , Venkatraman Priya , Foster E. Johan , Crooks Peter A. , A. Hestekin Jamie
Published: April 2020

The 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) oxidation of cellulose, when mediated with Oxone® (KHSO5), can be performed simply and under mild conditions. Furthermore, the products of the reaction can be isolated into two major components: Oxone®-mediated TEMPO-oxidized cellulose nanomaterials Form I and Form II (OTO-CNM Form I and Form II). This study focuses on the characterization of the properties of OTO-CNMs. Nanoparticle-sized cellulose fibers of 5 and 16 nm, respectively, were confirmed through electron microscopy. Infrared spectroscopy showed that the most carboxylation presented in Form II. Conductometric titration showed a two-fold increase in carboxylation from Form I (800 mmol/kg) to Form II (1600 mmol/kg). OTO-CNMs showed cellulose crystallinity in the range of 64–68% and crystallite sizes of 1.4–3.3 nm, as shown through XRD. OTO-CNMs show controlled variability in hydrophilicity with contact angles ranging from 16 to 32°, within or below the 26–47° reported in the literature for TEMPO-oxidized CNMs. Newly discovered OTO-CNM Form II shows enhanced hydrophilic properties as well as unique crystallinity and chemical functionalization in the field of bio-sourced material and nanocomposites.
PDADMAC/PSS Oligoelectrolyte Multilayers: Internal Structure and Hydration Properties at Early Growth Stages from Atomistic Simulations
Authors: Sánchez Pedro A. , Vögele Martin , Smiatek Jens , Qiao Baofu , Sega Marcello , Holm Christian
Published: April 2020

We analyze the internal structure and hydration properties of poly(diallyl dimethyl ammonium chloride)/poly(styrene sulfonate sodium salt) oligoelectrolyte multilayers at early stages of their layer-by-layer growth process. Our study is based on large-scale molecular dynamics simulations with atomistic resolution that we presented recently [Sánchez et al., Soft Matter 2019, 15, 9437], in which we produced the first four deposition cycles of a multilayer obtained by alternate exposure of a flat silica substrate to aqueous electrolyte solutions of such polymers at 0.1M of NaCl. In contrast to any previous work, here we perform a local structural analysis that allows us to determine the dependence of the multilayer properties on the distance to the substrate. We prove that the large accumulation of water and ions next to the substrate observed in previous overall measurements actually decreases the degree of intrinsic charge compensation, but this remains as the main mechanism within the interface region. We show that the range of influence of the substrate reaches approximately 3 nm, whereas the structure of the outer region is rather independent from the position. This detailed characterization is essential for the development of accurate mesoscale models able to reach length and time scales of technological interest.
Antiproliferative Properties of Papaver rhoeas Ovule Extracts and Derived Fractions Tested on HL60 Leukemia Human Cells
Authors: Ovidi Elisa , Laghezza Masci Valentina , Garzoli Stefania , Gambellini Gabriella , Keita Saran Vittoria , Zago Daniele , Turchetti Giovanni , Modesti Lorenzo , Tiezzi Antonio
Published: April 2020

Papaver rhoeas plant is common in many regions worldwide and contributes to the landscape with its red flower. In the present study we first carried out morphological investigation by optical and scanning electron microscopy of the ovules within the ovary. After ovules’ isolation we prepared extracts to test possible cytotoxic activities on HL60 leukemia human cells and investigated the extracts using thin-layer chromatography (TLC) and gas-chromatography/mass spectrometry (GC-MS). P. rhoeas ovules showed an elongated, round shape and the presence of ordered sculptures on the ovule surface. The ovule extracts showed cytotoxic activity on HL60 human cells mainly found in some TLC-isolated spots. Compounds consisting of active spots were identified by GC-MS investigations. Our findings on the P. rhoeas ovule compounds open perspectives for further investigations of TLC-isolated spots on other human cancer cell lines.
New Acidic Precursor and Acetone-Based Solvent for Fast Perovskite Processing via Proton-Exchange Reaction with Methylamine
Authors: A. Fateev Sergey , I. Marchenko Ekaterina , A. Petrov Andrey , A. Goodilin Eugene , B. Tarasov Alexey
Published: April 2020

A new solvent system for PbI2 based on HI solution in acetone with a low boiling point is proposed. High solubility of PbI2 is caused by the formation of iodoplumbate complexes, and reaches a concentration of 1.6 M. Upon its crystallization metastable solvate phases PbI2∙HI∙n{(CH3)2CO} are formed. The latter allows for their easy deposition on substrates in a form of smooth and uniform thin films by spin-coating. Through a fast acid-base reaction with a gaseous amine, the films of the intermediate phase can be completely converted to single-phase perovskite films. The developed method allows one to form smooth perovskite films with high crystallinity with a thickness up to 1 μm. Due to easy and fast processing, the developed method can be promising for perovskite technology upscaling.
Profiling of Individual Desulfo-Glucosinolate Content in Cabbage Head (Brassica oleracea var. capitata) Germplasm
Authors: Bhandari Shiva Ram , Rhee Juhee , Choi Chang Sun , Jo Jung Su , Shin Yu Kyeong , Lee Jun Gu
Published: April 2020

Individual glucosinolates (GSLs) were assessed to select cabbage genotypes for a potential breeding program. One hundred forty-six cabbage genotypes from different origins were grown in an open field from March to June 2019; the cabbage heads were used for GSL analyses. Seven aliphatics [glucoiberin (GIB), progoitrin (PRO), epi-progoitrin (EPI), sinigrin (SIN), glucoraphanin (GRA), glucoerucin (GER) and gluconapin (GNA)], one aromatic [gluconasturtiin (GNS)] and four indolyl GSLs [glucobrassicin (GBS), 4-hydroxyglucobrassicin (4HGBS), 4-methoxyglucobrassicin (4MGBS), neoglucobrassicin (NGBS)] were found this study. Significant variation was observed in the individual GSL content and in each class of GSLs among the cabbage genotypes. Aliphatic GSLs were predominant (58.5%) among the total GSLs, followed by indolyl GSL (40.7%) and aromatic GSLs (0.8%), showing 46.4, 51.2 and 137.8% coefficients of variation, respectively. GIB, GBS and NGBS were the most common GSLs found in all genotypes. GBS was the most dominant GSL, with an average value of 3.91 µmol g−1 (0.79 to 13.14 µmol g−1). SIN, GIB, PRO and GRA were the other major GSLs, showing average values of 3.45, 1.50, 0.77 and 0.62 µmol g−1, respectively. The genotypes with relatively high contents of GBS, SIN, GIB and GRA warrant detailed studies for future breeding programs since the hydrolysis products of these GSLs have several anti-cancer properties.