bluuebunny/crossref_metadata_2025 huggingface dataset:
A Computational Thermodynamics-Assisted Development of Sn-Bi-In-Ga Quaternary Alloys as Low-Temperature Pb-Free Solders
Authors: Yang Chih-han , Zhou Shiqi , Lin Shih-kang , Nishikawa Hiroshi
Published: February 2019

Low-temperature lead (Pb)-free solders are demanding in the electronic packaging industry, because it would open the door for various economic choices of polymeric materials as substrates and also revives the lower cost processes. Here, we proposed a tin–bismuth–indium–gallium (Sn-52.5Bi-2.68In-1Ga, SBIG (in wt.%)) quaternary low-temperature solder, designed based on systematic CALPHAD (CALculation of PHAse Diagram)-type thermodynamic calculations and corresponding key experiments. The solidification behavior of SBIG was carefully elaborated based on the computations using the lever rule and the Scheil model, and the experiments in terms of thermal analyses and microstructures of sample produced with step-quenching and various cooling rates. The mechanical properties of as-cast and 80 °C-annealed SBIG as well as their microstructures and fracture surfaces were evaluated in the tensile tests. The proposed SBIG solder is with a low liquidus temperature of 141.9 °C and is typically composed of the primary (Sn) phase, the (Sn) + (Bi) eutectic structure and a small amount of (Ga) phase. Air cooling has been identified as a satisfactory cooling rate, which would not lead to the formation of the brittle BiIn intermetallic compound. The as-cast SBIG solder exhibited high yield strength (YS) of 43.7 MPa, high ultimate tensile strength (UTS) of 53.3 MPa and an extremely large elongation of 97.3% as comparing to the conventional eutectic Sn-58Bi solder (YS: 43.1 MPa, UTS: 49.5 MPa, and elongation: 37.5%). However, the proposed SBIG solder does not possess qualified thermal stability, that significant degradation in both strength and elongation were observed after being subjected to extensive thermal ageing at 80 °C for 504 h.
p-n Control of AlMgB14-Based Thermoelectric Materials by Metal Site Occupancy
Authors: Fujima Takuya , Shimizu Natsuki , Arimatsu Hideki
Published: February 2019

The mechanism for the p-n control of AlMgB14-based thermoelectric material was investigated using Rietveld refinement and the first principle calculation. The p- and n-type AlMgB14-based thermoelectric materials were prepared by spark plasma sintering (SPS) with changing raw powder mixture ratio. Temperature dependence of Seebeck coefficient and electrical conductivity were different between the two types of samples. Seebeck coefficient shifted from positive to negative with increasing the number of valence electrons in the metal sites calculated by the metal site occupancy. The density of states and electron density distribution indicated that the electrons transfer from metal atoms to the B atoms.
The Influence of Granite Cutting Waste on The Properties of Ultra-High Performance Concrete
Authors: López Boadella Íñigo , López Gayarre Fernando , Suárez González Jesús , Gómez-Soberón José Manuel , López-Colina Pérez Carlos , Serrano López Miguel , de Brito Jorge
Published: February 2019

This study analyzes the effect of using waste by-products generated in the process of granite cutting as part of the granular structure of Ultra High Performance Concrete (UHPC). The manufactured concrete has a compressive strength greater than 115 MPa. This study substitutes 35%, 70% and 100% of the volume of micronized quartz powder (<40 μm) with granite cutting waste. This is an innovative study where the feasibility of using waste from granite quarries as a replacement for micronized quartz in UHPC has been analyzed. The results show an improvement in the workability and compressive strength of UHPC, for all substitution ratios. The flexural strength and tensile strength increase when the substitution ratio is 35%, and even the values obtained for 100% substitution are acceptable. In view of the results obtained in this study, granite cutting waste, instead of the micronized quartz powder usually used, is a viable alternative for the manufacture of expectedly more sustainable UHPC.
Near-Surface Material Phases and Microstructure of Scandate Cathodes
Authors: Liu Xiaotao , Vancil Bernard K. , Beck Matthew J. , Balk Thomas John
Published: February 2019

Scandate cathodes that were fabricated using the liquid-solid process and that exhibited excellent emission performance were characterized using complementary state-of-the-art electron microscopy techniques. Sub-micron BaAl2O4 particles were observed on the surfaces and edges of tungsten particles, as seen in cross-section samples extracted from the scandate cathode surface regions. Although several BaAl2O4 particles were observed to surround smaller Sc2O3 nanoparticles, no chemical mixing of the two oxides was detected, and in fact the distinct oxide phases were separately verified by chemical analysis and also by 3D elemental tomography. Nanobeam electron diffraction confirmed that the crystal structure throughout W grains is body-centered cubic, indicating that they are metallic W and did not experience noticeable changes, even near the grain surfaces, as a result of the numerous complex chemical reactions that occur during cathode impregnation and activation. 3D reconstruction further revealed that internal Sc/Sc2O3 particles tend to exhibit a degree of correlated arrangement within a given W particle, rather than being distributed uniformly throughout. Moreover, the formation of Sc/Sc2O3 particles within W grains may arise from W surface roughening that occurs during the liquid-solid synthesis process.
Statistical Analysis and Preliminary Study on the Mix Proportion Design of Self-Compacting Steel Fiber Reinforced Concrete
Authors: Ding Xinxin , Zhao Minglei , Zhou Siyi , Fu Yan , Li Changyong
Published: February 2019

With the sustainable development of green construction materials in civil engineering, self-compacting steel fiber reinforced concrete (SC-SFRC) has attracted widespread attention due to its superior self-compacting performance and excellent hardened properties. In this paper, 301 groups of test data from published literatures were collected to quantify the characteristics of the mix proportion of SC-SFRC. The type, aspect ratio and volume fraction of steel fiber commonly used in SC-SFRC are discussed and the effects of steel fiber on the workability and mechanical properties of SC-SFRC are statistically studied. The relationship of cubic compressive strength and water-to-binder ratio and that of the splitting tensile strengths between SC-SFRC and referenced self-compacting concrete (SCC) are also evaluated. Based on these analyses, the reasonable ranges of material components in the mix proportion design of SC-SFRC are determined. The results showed that with several adjusted parameters, the calculation model of the water-to-binder ratio for the mix proportion design of ordinary concrete is suitable for SC-SFRC. The calculation model of tensile strength is suggested for SC-SFRC with various types of steel fiber.
Some Remarks on Harmonic Functions in Minkowski Spaces
Authors: Yin Songting
Published: February 2019

We prove that in Minkowski spaces, a harmonic function does not necessarily satisfy the mean value formula. Conversely, we also show that a function satisfying the mean value formula is not necessarily a harmonic function. Finally, we conclude that in a Minkowski space, if all harmonic functions have the mean value property or any function satisfying the mean value formula must be a harmonic function, then the Minkowski space is Euclidean.
Convergence Analysis of Weighted-Newton Methods of Optimal Eighth Order in Banach Spaces
Authors: Sharma Janak Raj , Argyros Ioannis K. , Kumar Sunil
Published: February 2019

We generalize a family of optimal eighth order weighted-Newton methods to Banach spaces and study their local convergence. In a previous study, the Taylor expansion of higher order derivatives is employed which may not exist or may be very expensive to compute. However, the hypotheses of the present study are based on the first Fréchet-derivative only, thereby the application of methods is expanded. New analysis also provides the radius of convergence, error bounds and estimates on the uniqueness of the solution. Such estimates are not provided in the approaches that use Taylor expansions of derivatives of higher order. Moreover, the order of convergence for the methods is verified by using computational order of convergence or approximate computational order of convergence without using higher order derivatives. Numerical examples are provided to verify the theoretical results and to show the good convergence behavior.
Primes in Intervals and Semicircular Elements Induced by p-Adic Number Fields

Q
p

over Primes p
Authors: Cho Ilwoo , Jorgensen Palle
Published: February 2019

In this paper, we study free probability on (weighted-)semicircular elements in a certain Banach *-probability space ( LS , τ 0 ) induced by measurable functions on p-adic number fields Q p over primes p . In particular, we are interested in the cases where such free-probabilistic information is affected by primes in given closed intervals of the set R of real numbers by defining suitable “truncated” linear functionals on LS .
Electronic Structure Calculations of Oxygen Atom Transport Energetics in the Presence of Screw Dislocations in Tungsten
Authors: Zhao Yue , Dezerald Lucile , Marian Jaime
Published: February 2019

Plastic flow in body-centered cubic (bcc) alloys is governed by the thermally-activated motion of screw dislocations in close-packed planes. In bcc interstitial solid solutions, solute diffusion can occur at very fast rates owing to low migration energies and solute concentrations. Under mechanical loading, solutes may move on the same or similar time scale as dislocations glide, even at low temperatures, potentially resulting in very rich co-evolution processes that may have important effects in the overall material response. It is therefore important to accurately quantify the coupling between interstitial impurities and dislocations, so that larger-scale models can correctly account for their interactions. In this paper, we use electronic structure calculations to obtain the energetics of oxygen diffusion under stress and its interaction energy with screw dislocation cores in bcc tungsten. We find that oxygen atoms preferentially migrate from tetrahedral to tetrahedral site with an energy of 0.2 eV. This energy couples only weakly to hydrostatic and deviatoric deformations, with activation volumes of less than 0.02 and 0.02 b 3 , respectively. The strongest effect is found for the inelastic interaction between O atoms and screw dislocation cores, which leads to attractive energies between 1.2 and 1.9 eV and sometimes triggers a transformation of the screw dislocation core from an easy core configuration to a hard core configuration.
Mineral Mapping and Vein Detection in Hyperspectral Drill-Core Scans: Application to Porphyry-Type Mineralization
Authors: Tusa Laura , Andreani Louis , Khodadadzadeh Mahdi , Contreras Cecilia , Ivascanu Paul , Gloaguen Richard , Gutzmer Jens
Published: February 2019

The rapid mapping and characterization of specific porphyry vein types in geological samples represent a challenge for the mineral exploration and mining industry. In this paper, a methodology to integrate mineralogical and structural data extracted from hyperspectral drill-core scans is proposed. The workflow allows for the identification of vein types based on minerals having significant absorption features in the short-wave infrared. The method not only targets alteration halos of known compositions but also allows for the identification of any vein-like structure. The results consist of vein distribution maps, quantified vein abundances, and their azimuths. Three drill-cores from the Bolcana porphyry system hosting veins of variable density, composition, orientation, and thickness are analysed for this purpose. The results are validated using high-resolution scanning electron microscopy-based mineral mapping techniques. We demonstrate that the use of hyperspectral scanning allows for faster, non-invasive and more efficient drill-core mapping, providing a useful tool for complementing core-logging performed by on-site geologists.
Enhanced Anti-Allergic Activity of Milk Casein Phosphopeptide by Additional Phosphorylation in Ovalbumin-Sensitized Mice
Authors: Lebetwa Ntshepisa , Suzuki Yuta , Tanaka Sachi , Nakamura Soichiro , Katayama Shigeru
Published: February 2019

The proteolytic digest of milk casein, known as casein phosphopeptide (CPP-III), exhibits diverse biological activities, including calcium absorption and antioxidant activities. We hypothesized that the additional phosphorylation of this peptide can enhance its immunomodulatory activity such as suppression of allergy-associated cytokine and antigen-specific immune response. This study was conducted to assess whether oral intake of additionally phosphorylated CPP-III (P-CPP) attenuates ovalbumin (OVA)-induced IgE-mediated allergic reactions because of the additional phosphate groups. Female BALB/c mice were intraperitoneally sensitized with OVA twice at intervals of 14 days and then orally fed native CPP-III (N-CPP), P-CPP, and dephosphorylated CPP-III (D-CPP) for 6 weeks. Next, the mice were orally challenged with 50 mg of OVA. Oral administration of P-CPP suppressed total and specific IgE levels in the serum. Mice fed P-CPP exhibited low levels of OVA-specific IgG1 and increased OVA-specific IgG2a. P-CPP also suppressed IL-4 production, while D-CPP showed similar a level compared to that of the control. Further, P-CPP increased the population of the T follicular helper (Tfh) cell in the spleen. These results suggest that additional phosphorylation of CPP can enhance the attenuation of allergen-specific IgE-modulated allergic reactions in a murine food allergy model.
Synthesis and Biological Evaluation of Novel Thiazolyl-Coumarin Derivatives as Potent Histone Deacetylase Inhibitors with Antifibrotic Activity
Authors: Pardo-Jiménez Viviana , Navarrete-Encina Patricio , Díaz-Araya Guillermo
Published: February 2019

New histone deacetylases (HDAC) inhibitors with low toxicity to non-cancerous cells, are a prevalent issue at present because these enzymes are actively involved in fibrotic diseases. We designed and synthesized a novel series of thiazolyl-coumarins, substituted at position 6 (R = H, Br, OCH3), linked to classic zinc binding groups, such as hydroxamic and carboxylic acid moieties and alternative zinc binding groups such as disulfide and catechol. Their in vitro inhibitory activities against HDACs were evaluated. Disulfide and hydroxamic acid derivatives were the most potent ones. Assays with neonatal rat cardiac fibroblasts demonstrated low cytotoxic effects for all compounds. Regarding the parameters associated to cardiac fibrosis development, the compounds showed antiproliferative effects, and triggered a strong decrease on the expression levels of both α-SMA and procollagen I. In conclusion, the new thiazolyl-coumarin derivatives inhibit HDAC activity and decrease profibrotic effects on cardiac fibroblasts.
Gas-Phase Fragmentation Reactions of Protonated Cystine using High-Resolution Tandem Mass Spectrometry
Authors: Zhang Pengwei , Chan Wan , Ang Irene L. , Wei Rui , Lam Melody M. T. , Lei Kate M. K. , Poon Terence C. W.
Published: February 2019

Cystine is an important biomolecule in living systems. Although collision-induced dissociation (CID)-based tandem mass spectrometry (MS/MS) is commonly applied for identification and quantification of cystine in both biomedical and nutritional studies, gas-phase fragmentation reactions of cystine in CID has remained unclear. This may lead to improper assay design, which may in turn result in inaccurate test results. In the present study, gas-phase fragmentation reactions of protonated cystine in CID were characterized using high-resolution MS/MS and pseudo MS3. Fragmentations started from cleavages of disulfide bond (S–S) and carbon–sulfur bond (C–S). When cleaving at the S–S, protonated cysteine was generated as one of the predominant fragmentation products. Minor fragmentations started from the loss of H2O + CO and the loss of NH3. Our results reveal that the m/z 74 fragment ion, which is commonly used as a product ion of the transition (precursor/product ion pair) in selected reaction monitoring (SRM) assay for quantifying cystine, comprises two isobaric fragments originating from different parts of cystine. This indicates the need for careful selection of a stable isotope-labeled cystine molecule as an internal standard for SRM assays. Here, we provide a clear picture of the fragmentation reactions of protonated cystine in CID. It can serve as a useful guidance for designing MS/MS-based assays for cystine testing.
Micrometric Wrinkled Patterns Spontaneously Formed on Hydrogel Thin Films via Argon Plasma Exposure
Authors: González-Henríquez Carmen M. , Veliz-Silva Diego F. , Sarabia-Vallejos Mauricio A. , del Campo-García Adolfo , Rodríguez-Hernández Juan
Published: February 2019

The generation of microstructured patterns on the surface of a specific polymeric material could radically improve their performance in a particular application. Most of the interactions with the environment occur at the material interface; therefore, increasing the exposed active surface considerably improves their range of application. In this article, a simple and reliable protocol to form spontaneous wrinkled patterns using a hydrogel layer is reported. For this purpose, we took advantage of the doctor blade technique in order to generate homogenous films over solid substrates with controlled thickness and large coverage. The hydrogel wrinkle formation involves a prepolymerization step which produces oligomers leading to a solution with increased viscosity, enough for doctor blade deposition. Subsequently, the material was exposed to vacuum and plasma to trigger wrinkled pattern formation. Finally, a UV-polymerization treatment was applied to fix the undulations on top. Interestingly, the experimental parameters allowed us to finely tune the wrinkle characteristics (period, amplitude, and orientation). For this study, two main aspects were explored. The first one is related to the role of the substrate functionalization on the wrinkle formation. The second study correlates the deswelling time and its relationship with the dimensions and distribution of the wrinkle pattern. In the first batch, four different 3-(trimethoxysilyl)propyl methacrylate (TSM) concentrations were used to functionalize the substrate in order to enhance the adhesion between hydrogel film and the substrate. The wrinkles formed were characterized in terms of wrinkle amplitude, wavelength, pattern roughness, and surface Young modulus, by using AFM in imaging and force spectroscopy modes. Moreover, the chemical composition of the hydrogel film cross-section and the effect of the plasma treatment were analyzed with confocal Raman spectroscopy. These results demonstrated that an oxidized layer was formed on top of the hydrogel films due to the exposure to an argon plasma.
Education and Attachment: Guidelines to Prevent School Failure
Authors: de Castro Rosa Maria , Pereira Dora Isabel Fialho
Published: February 2019

Portuguese schools have high student failure and early school leaving rates (Pordata, 2017) giving rise to a number of initiatives aimed at their reduction. The “Alternative Curricular Course” (ACC) promotes the learning of basic skills, specifically in Portuguese language and Mathematics, to support logical reasoning and artistic, vocational, and professional development. Its main goal is the fulfilment of compulsory schooling and the reduction of academic failure. Research based on attachment theory (Bowlby, 1969) suggests that different internal working models of attachment are associated with different characteristics of social, academic, emotional, and behavioural competencies that may interfere in the quality of relationships that young people establish in school, especially with teachers, and also influence their academic performance. This study evaluates the relationship between internal working models of students, their perceptions of the quality of their relationships with teachers, and their academic performance using three measures: (i) the “Inventory of Attachment in Childhood and Adolescence” (IACA) measure, (ii) the “Inventory of Parent and Peer Attachment” (IPPA) measure—concerning the attachment to teacher”, and (iii) a socio-demographic questionnaire on a sample of 305 students from the 8th grade of regular education (RE) and the ACC. The results reveal that students on the ACC exhibit a less secure internal working model than students in RE, and that the perception of the quality of the student-teacher relationship, regarding the dimension of acceptance and understanding by the teachers, is associated with a better academic performance. These results align with those of other recent studies in support of the conclusion that the process of attachment has a significant influence on educational contexts, consistent with attachment and related theories.
Phytochemicals of Cinnamomi Cortex: Cinnamic Acid, but not Cinnamaldehyde, Attenuates Oxaliplatin-Induced Cold and Mechanical Hypersensitivity in Rats
Authors: Chae Hyeon Kyeong , Kim Woojin , Kim Sun Kwang
Published: February 2019

A chemotherapy drug, oxaliplatin, induces cold and mechanical hypersensitivity, but effective treatments for this neuropathic pain without side effects are still lacking. We previously showed that Cinnamomi Cortex suppresses oxaliplatin-induced pain behaviors in rats. However, it remains unknown which phytochemical of Cinnamomi Cortex plays a key role in that analgesic action. Thus, here we investigated whether and how cinnamic acid or cinnamaldehyde, major components of Cinnamomi Cortex, alleviates cold and mechanical allodynia induced by a single oxaliplatin injection (6 mg/kg, i.p.) in rats. Using an acetone test and the von Frey test for measuring cold and mechanical allodynia, respectively, we found that administration of cinnamic acid, but not cinnamaldehyde, at doses of 10, 20 and 40 mg/kg (i.p.) significantly attenuates the allodynic behaviors in oxaliplatin-injected rats with the strongest effect being observed at 20 mg/kg. Our in vivo extracellular recordings also showed that cinnamic acid (20 mg/kg, i.p.) inhibits the increased activities of spinal wide dynamic range neurons in response to cutaneous mechanical and cold stimuli following the oxaliplatin injection. These results indicate that cinnamic acid has an effective analgesic action against oxaliplatin-induced neuropathic pain through inhibiting spinal pain transmission, suggesting its crucial role in mediating the effect of Cinnamomi Cortex.
Daidzein Intake Is Associated with Equol Producing Status through an Increase in the Intestinal Bacteria Responsible for Equol Production
Authors: Iino Chikara , Shimoyama Tadashi , Iino Kaori , Yokoyama Yoshihito , Chinda Daisuke , Sakuraba Hirotake , Fukuda Shinsaku , Nakaji Shigeyuki
Published: February 2019

Equol is a metabolite of isoflavone daidzein and has an affinity to estrogen receptors. Although equol is produced by intestinal bacteria, the association between the status of equol production and the gut microbiota has not been fully investigated. The aim of this study was to compare the intestinal bacteria responsible for equol production in gut microbiota between equol producer and non-producer subjects regarding the intake of daidzein. A total of 1044 adult subjects who participated in a health survey in Hirosaki city were examined. The concentration of equol in urine was measured by high-performance liquid chromatography. The relative abundances of 8 bacterial species responsible for equol production in the gut microbiota was assessed using 16S rRNA amplification. There were 458 subjects identified as equol producers. The proportion of equol production status and the intake of daidzein increased with age. Daily intake of daidzein was larger in equol-producer. The intestinal bacteria, which convert daidzein to equol were present in both equol producers and non-producers. However, the relative abundance and the prevalence of Asaccharobacter celatus and Slackia isoflavoniconvertens were significantly higher in equol producers than those in equol non-producers. The intestinal bacteria that convert daidzein to equol are present in not only the equol producers but also in the non-producers. The daidzein intake is associated with the equol production status through an increase of A. celatus and S. isoflavoniconvertens in the gut microbiota.
Development and Characterization of Chitosan Microparticles-in-Films for Buccal Delivery of Bioactive Peptides
Authors: Batista Patrícia , Castro Pedro , Madureira Ana Raquel , Sarmento Bruno , Pintado Manuela
Published: February 2019

Nowadays, bioactive peptides are used for therapeutic applications and the selection of a carrier to deliver them is very important to increase the efficiency, absorption, release, bioavailability and consumer acceptance. The aim of this study was to develop and characterize chitosan-based films loaded with chitosan microparticles containing a bioactive peptide (sequence: KGYGGVSLPEW) with antihypertensive properties. Films were prepared by the solvent casting method, while the microparticles were prepared by ionic gelation. The final optimized chitosan microparticles exhibited a mean diameter of 2.5 µm, a polydispersity index of 0.46, a zeta potential of +61 mV and a peptide association efficiency of 76%. Chitosan films were optimized achieving the final formulation of 0.79% (w/v) of chitosan, 6.74% (w/v) of sorbitol and 0.82% (w/v) of citric acid. These thin (±0.100 mm) and transparent films demonstrated good performance in terms of mechanical and biological properties. The oral films developed were flexible, elastic, easy to handle and exhibited rapid disintegration (30 s) and an erosion behavior of 20% when they came into contact with saliva solution. The cell viability (75–99%) was proved by methylthiazolydiphenyl-tetrazolium bromide (MTT) assay with TR146 cells. The chitosan mucoadhesive films loaded with peptide–chitosan microparticles resulted in an innovative approach to perform administration across the buccal mucosa, because these films present a larger surface area, leading to the rapid disintegration and release of the antihypertensive peptide under controlled conditions in the buccal cavity, thus promoting bioavailability.
Effect of an Experimental Formulation Containing Chlorhexidine on Pathogenic Biofilms and Drug Release Behavior in the Presence or Absence of Bacteria
Authors: Ré Ana Carolina S. , Bonjovanni Maria Carolina , Ferreira Maíra P. , Freitas Osvaldo , Aires Carolina P.
Published: February 2019

(1) Background: For any antibacterial oral formulation to be successful, it must present effects in the presence of biofilms. Therefore, our aim is to analyze the drug release and the antibiofilm effects of a semi-solid formulation containing chlorhexidine (CHX) in the presence of pathogenic biofilms. (2) Methods: The biofilms of Streptococcus mutans (n = 6) or Porphyromonas gingivalis (n = 3) were formed for 6 and 4 days, respectively, being exposed to: 1) a CHX system or 2) vehicle control without CHX. A group without treatment was included as negative control. The acidogenicity, CHX quantification and bacterial viability were determined. A dissolution assay in a buffer and culture medium in the absence of bacteria was also performed. (3) Results: Although the CHX quantification in the culture medium of both biofilms was lower compared to the buffer (p < 0.05) and the culture medium in the absence of bacteria, the CHX system was able to display antibiofilm effects until 96 h for the S. mutans biofilms (p < 0.05) and 72 h for the P. gingivalis biofilms (p < 0.05). (4) Conclusions: The experimental formulation is able to extend chlorhexidine effects, even in challenging conditions such as in the presence of bacteria, allowing the in vitro control of cariogenic biofilms for 4 days and periodontopathogenic biofilms for 3 days.
A Spotlight on Rad52 in Cyanidiophytina (Rhodophyta): A Relic in Algal Heritage
Authors: Del Mondo Angelo , Iovinella Manuela , Petriccione Milena , Nunziata Angelina , Davis Seth J. , Cioppa Diana , Ciniglia Claudia
Published: February 2019

The RADiation sensitive52 (RAD52) protein catalyzes the pairing between two homologous DNA sequences’ double-strand break repair and meiotic recombination, mediating RAD51 loading onto single-stranded DNA ends, and initiating homologous recombination and catalyzing DNA annealing. This article reports the characterization of RAD52 homologs in the thermo-acidophilic Cyanidiophyceae whose genomes have undergone extensive sequencing. Database mining, phylogenetic inference, prediction of protein structure and evaluation of gene expression were performed in order to determine the functionality of the RAD52 protein in Cyanidiophyceae. Its current function in Cyanidiophytina could be related to stress damage response for thriving in hot and acidic environments as well as to the genetic variability of these algae, in which, conversely to extant Rhodophyta, sexual mating was never observed.
Synthesis and Gas-Permeation Characterization of a Novel High-Surface Area Polyamide Derived from 1,3,6,8-Tetramethyl-2,7-diaminotriptycene: Towards Polyamides of Intrinsic Microporosity (PIM-PAs)
Authors: Genduso Giuseppe , Ghanem Bader S. , Wang Yingge , Pinnau Ingo
Published: February 2019

A triptycene-based diamine, 1,3,6,8-tetramethyl-2,7-diamino-triptycene (TMDAT), was used for the synthesis of a novel solution-processable polyamide obtained via polycondensation reaction with 4,4′-(hexafluoroisopropylidene)bis(benzoic acid) (6FBBA). Molecular simulations confirmed that the tetrasubstitution with ortho-methyl groups in the triptycene building block reduced rotations around the C–N bond of the amide group leading to enhanced fractional free volume. Based on N2 sorption at 77 K, 6FBBA-TMDAT revealed microporosity with a Brunauer–Emmett–Teller (BET) surface area of 396 m2 g−1; to date, this is the highest value reported for a linear polyamide. The aged 6FBBA-TMDAT sample showed moderate pure-gas permeabilities (e.g., 198 barrer for H2, ~109 for CO2, and ~25 for O2) and permselectivities (e.g., αH2/CH4 of ~50) that position this polyamide close to the 2008 H2/CH4 and H2/N2 upper bounds. CO2–CH4 mixed-gas permeability experiments at 35 °C demonstrated poor plasticization resistance; mixed-gas permselectivity negatively deviated from the pure-gas values likely, due to the enhancement of CH4 diffusion induced by mixing effects.
Solution Blown Nylon 6 Nanofibrous Membrane as Scaffold for Nanofiltration
Authors: Liu Ya , Zhang Gaokai , Zhuang Xupin , Li Sisi , Shi Lei , Kang Weimin , Cheng Bowen , Xu Xianlin
Published: February 2019

In this work, a nylon 6 nanofibrous membrane was prepared via solution blowing technology and followed hot-press as scaffold for nanofiltration. The structure and properties of the hot-pressed nylon 6 nanofibrous membrane (HNM) were studied the effect of hot-pressing parameters and areal densities. Then an ultra-thin polyamide (PA) active layer was prepared by interfacial polymerization on HNM. The effects of nanofibrous scaffolds on the surface properties of ultra-thin nanofiltration membranes and their filtration performance were studied. Results showed that the nylon 6 nanofibers prepared at a concentration of 15 wt % had a good morphology and diameter distribution and the nanofibers were stacked more tightly and significantly reduced in diameter after hot pressing at 180 °C under the pressure of 15 MPa for 10 s. When the porous scaffold was prepared, HNM with an areal density of 9.4 and 14.1 g/m2 has a better apparent structure, a smaller pore size, a higher porosity and a greater strength. At the same time, different areal densities of HNM have an important influence on the preparation and properties of nanofiltration membranes. With the increase of areal density, the uniformity of HNM increased while their surface roughness and pore size decreased, which is beneficial to the establishment of PA barrier layer. With areal density of 9.4 and 14.1 g/m2, the as-prepared nanofiltration membrane has a smoother surface and more outstanding filtration performance. The pure water flux is 13.1 L m−2 h−1 and the filtration efficiencies for NaCl and Na2SO4 are 81.3% and 85.1%, respectively.
New Alginate/PNIPAAm Matrices for Drug Delivery
Authors: Cheaburu-Yilmaz Catalina N. , Lupuşoru Catalina Elena , Vasile Cornelia
Published: February 2019

This paper deals with a comparative study on the interpolymeric complexes of alginate poly(N-isopropyl acryl amide (PNIPAAm) and corresponding graft copolymers with various compositions in respect to their toxicity, biocompatibility and in vitro and in vivo release of theophylline (THP). Loading of the various matrices with theophylline and characterization of loaded matrices was studied by near infrared spectroscopy–chemical imaging (NIR–CI) analysis, scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). It was appreciated that THP loading is higher than 40% and the drug is relatively homogeneous distributed within all matrices because of some specific interactions between components of the system. All samples have been found to be non-toxic and biocompatible. It was established that graft copolymers having a good stability show a better drug carrier ability, a higher THP loading, a prolonged release (longer release duration for graft copolymers of 235.4–302.3 min than that for IPC 72/28 of 77.6 min, which means approximately four times slower release from the graft copolymer-based matrices than from the interpolymeric complex) and a good bioavailability. The highest values for THP loading (45%), prolonged release (302.3 min) and bioavailability (175%) were obtained for graft copolymer AgA-g-PNIPAAm 68. The drug release mechanism varies with composition and architecture of the matrix.
Mechanically Robust Hybrid POSS Thermoplastic Polyurethanes with Enhanced Surface Hydrophobicity
Authors: Song Xiuhuan , Zhang Xiaoxiao , Li Tianduo , Li Zibiao , Chi Hong
Published: February 2019

A series of hybrid thermoplastic polyurethanes (PUs) were synthesized from bi-functional polyhedral oligomeric silsesquioxane (B-POSS) and polycaprolactone (PCL) using 1,6-hexamethylene diisocyanate (HDI) as a coupling agent for the first time. The newly synthesized hybrid materials were fully characterized in terms of structure, morphology, thermal and mechanical performance, as well as their toughening effect toward polyesters. Thermal gravimeter analysis (TGA) and differential scanning calorimetry (DSC) showed enhanced thermal stability by 76 °C higher in decomposition temperature (Td) of the POSS PUs, and 22 °C higher glass transition temperature (Tg) when compared with control PU without POSS. Static contact angle results showed a significant increment of 49.8° and 53.4° for the respective surface hydrophobicity and lipophilicity measurements. More importantly, both storage modulus (G’) and loss modulus (G’’) are improved in the hybrid POSS PUs and these parameters can be further adjusted by varying POSS content in the copolymer. As a biodegradable hybrid filler, the as-synthesized POSS PUs also demonstrated a remarkable effect in toughening commercial polyesters, indicating a simple yet useful strategy in developing high-performance polyester for advanced biomedical applications.
A Qualitative Study of Ramadan: A Month of Fasting, Family, and Faith
Authors: Alghafli Zahra , Hatch Trevan G. , Rose Andrew H. , Abo-Zena Mona M. , Marks Loren D. , Dollahite David C.
Published: February 2019

Islam is a major world religion and the Muslim population is one of the fastest growing religious populations in the Western world, including in the United States. However, few research studies have examined the lived religious experience of U.S. Muslim families. Much of the attention on Islam among researchers and the media tends to be on controversial aspects of the religion. The purpose of this paper is to examine the unique religious practice of the month-long fast of Ramadan, especially its perceived role on marital and familial relationships from an insider’s perspective. Content analysis of in-depth, qualitative interviews of twenty diverse Shia and Sunni Muslim families living in the United States (N = 47 individuals) yielded several emergent themes. This study presents and explores data on the focal theme: “fasting brings us closer together.” These data suggest that Ramadan serves a sacred, unifying, and integrating purpose for many of the 47 practicing Muslim mothers, fathers, and youth in this study. Meanings and processes involved in Ramadan and family relationships are explored and explained. Implications and applications of the research findings are discussed and some potential directions for future research are outlined.
Singularity Avoidance Control of a Non-Holonomic Mobile Manipulator for Intuitive Hand Guidance
Authors: Weyrer Matthias , Brandstötter Mathias , Husty Manfred
Published: February 2019

Mobile manipulators are robot systems capable of combining logistics and manipulation tasks. They thus fulfill an important prerequisite for the integration into flexible manufacturing systems. Another essential feature required for modern production facilities is a user-friendly and intuitive human-machine interaction. In this work the goal of code-less programming is addressed and an intuitive and safe approach to physically interact with such robot systems is derived. We present a natural approach for hand guiding a sensitive mobile manipulator in task space using a force torque sensor that is mount close to the end effector. The proposed control structure is capable of handling the kinematic redundancies of the system and avoid singular arm configurations by means of haptic feedback to the user. A detailed analysis of all possible singularities of the UR robot family is given and the functionality of the controller design is shown with laboratory experiments on our mobile manipulator.
Hydrologic Evaluation of TRMM and GPM IMERG Satellite-Based Precipitation in a Humid Basin of China
Authors: Zhang Zengxin , Tian Jiaxi , Huang Yuhan , Chen Xi , Chen Sheng , Duan Zheng
Published: February 2019

Tropical Rainfall Measurement Mission (TRMM) is one of the most popular global high resolution satellite-based precipitation products with a goal of measuring precipitation over the oceans and tropics. However, in recent years, the TRMM mission has come to an end. Its successor, Global Precipitation Measurement (GPM) mission was launched to measure the earth’s precipitation structure, with an aim to improve upon the TRMM project. Both of the precipitation products have their own strengths and weaknesses in resolution, accuracy, and availability. The aim of this study is to evaluate the hydrologic utilization of the TRMM and GPM products in a humid basin of China. The main findings of this study can be summarized as follows: (1) 3B42V7 generally outperforms 3B42V6 in terms of hydrologic performance. Meanwhile, 3B42RTV7 significantly outperforms 3B42RTV6, and showed close performance with the bias-adjusted TRMM Multi-satellite Precipitation Analysis (TMPA) products. (2) The GPM showed better agreement with gauge observation than the TMPA products with lower RB and higher correlation coefficient (CC) values at different time scales. (3) The VIC hydrological model generally outperformed the XAJ hydrological model with lower RB, higher Nash–Sutcliffe Coefficient of Efficiency (NSCE) and CC values; though the 3B42RTV6 and 3B42RTV7 showed higher CC values in simulating the streamflow hydrograph by using the VIC and XAJ hydrological models. It can be found that the conceptual hydrological model was enough for the hydrologic evaluation of TRMM and GPM IMERG satellite-based precipitation in a humid basin of China. This study provides a reference for the comparison of multiple models on watershed scale.
Validation of Copernicus Sentinel-2 Cloud Masks Obtained from MAJA, Sen2Cor, and FMask Processors Using Reference Cloud Masks Generated with a Supervised Active Learning Procedure
Authors: Baetens Louis , Desjardins Camille , Hagolle Olivier
Published: February 2019

The Sentinel-2 satellite mission, developed by the European Space Agency (ESA) for the Copernicus program of the European Union, provides repetitive multi-spectral observations of all Earth land surfaces at a high resolution. The Level 2A product is a basic product requested by many Sentinel-2 users: it provides surface reflectance after atmospheric correction, with a cloud and cloud shadow mask. The cloud/shadow mask is a key element to enable an automatic processing of Sentinel-2 data, and therefore, its performances must be accurately validated. To validate the Sentinel-2 operational Level 2A cloud mask, a software program named Active Learning Cloud Detection (ALCD) was developed, to produce reference cloud masks. Active learning methods allow reducing the number of necessary training samples by iteratively selecting them where the confidence of the classifier is low in the previous iterations. The ALCD method was designed to minimize human operator time thanks to a manually-supervised active learning method. The trained classifier uses a combination of spectral and multi-temporal information as input features and produces fully-classified images. The ALCD method was validated using visual criteria, consistency checks, and compared to another manually-generated cloud masks, with an overall accuracy above 98%. ALCD was used to create 32 reference cloud masks, on 10 different sites, with different seasons and cloud cover types. These masks were used to validate the cloud and shadow masks produced by three Sentinel-2 Level 2A processors: MAJA, used by the French Space Agency (CNES) to deliver Level 2A products, Sen2Cor, used by the European Space Agency (ESA), and FMask, used by the United States Geological Survey (USGS). The results show that MAJA and FMask perform similarly, with an overall accuracy around 90% (91% for MAJA, 90% for FMask), while Sen2Cor’s overall accuracy is 84%. The reference cloud masks, as well as the ALCD software used to generate them are made available to the Sentinel-2 user community.
A Highly Sensitive Pressure-Sensing Array for Blood Pressure Estimation Assisted by Machine-Learning Techniques
Authors: Huang Kuan-Hua , Tan Fu , Wang Tzung-Dau , Yang Yao-Joe
Published: February 2019

This work describes the development of a pressure-sensing array for noninvasive continuous blood pulse-wave monitoring. The sensing elements comprise a conductive polymer film and interdigital electrodes patterned on a flexible Parylene C substrate. The polymer film was patterned with microdome structures to enhance the acuteness of pressure sensing. The proposed device uses three pressure-sensing elements in a linear array, which greatly facilitates the blood pulse-wave measurement. The device exhibits high sensitivity (−0.533 kPa−1) and a fast dynamic response. Furthermore, various machine-learning algorithms, including random forest regression (RFR), gradient-boosting regression (GBR), and adaptive boosting regression (ABR), were employed for estimating systolic blood pressure (SBP) and diastolic blood pressure (DBP) from the measured pulse-wave signals. Among these algorithms, the RFR-based method gave the best performance, with the coefficients of determination for the reference and estimated blood pressures being R2 = 0.871 for SBP and R2 = 0.794 for DBP, respectively.
Vision Sensor Based Fuzzy System for Intelligent Vehicles
Authors: Kim Kwangsoo , Kim Yangho , Kwak Sooyeong
Published: February 2019

Those in the automotive industry and many researchers have become interested in the development of pedestrian protection systems in recent years. In particular, vision-based methods for predicting pedestrian intentions are now being actively studied to improve the performance of pedestrian protection systems. In this paper, we propose a vision-based system that can detect pedestrians using an on-dash camera in the car, and can then analyze their movements to determine the probability of collision. Information about pedestrians, including position, distance, movement direction, and magnitude are extracted using computer vision technologies and, using this information, a fuzzy rule-based system makes a judgement on the pedestrian’s risk level. To verify the function of the proposed system, we built several test datasets, collected by ourselves, in high-density regions where vehicles and pedestrians mix closely. The true positive rate of the experimental results was about 86%, which shows the validity of the proposed system.
An LSTM-Based Method with Attention Mechanism for Travel Time Prediction
Authors: Ran Xiangdong , Shan Zhiguang , Fang Yufei , Lin Chuang
Published: February 2019

Traffic prediction is based on modeling the complex non-linear spatiotemporal traffic dynamics in road network. In recent years, Long Short-Term Memory has been applied to traffic prediction, achieving better performance. The existing Long Short-Term Memory methods for traffic prediction have two drawbacks: they do not use the departure time through the links for traffic prediction, and the way of modeling long-term dependence in time series is not direct in terms of traffic prediction. Attention mechanism is implemented by constructing a neural network according to its task and has recently demonstrated success in a wide range of tasks. In this paper, we propose an Long Short-Term Memory-based method with attention mechanism for travel time prediction. We present the proposed model in a tree structure. The proposed model substitutes a tree structure with attention mechanism for the unfold way of standard Long Short-Term Memory to construct the depth of Long Short-Term Memory and modeling long-term dependence. The attention mechanism is over the output layer of each Long Short-Term Memory unit. The departure time is used as the aspect of the attention mechanism and the attention mechanism integrates departure time into the proposed model. We use AdaGrad method for training the proposed model. Based on the datasets provided by Highways England, the experimental results show that the proposed model can achieve better accuracy than the Long Short-Term Memory and other baseline methods. The case study suggests that the departure time is effectively employed by using attention mechanism.
An Analysis Method for Capacitive Micromachined Ultrasound Transducer (CMUT) Energy Conversion during Large Signal Operation
Authors: Pirouz Amirabbas , Degertekin F. Levent
Published: February 2019

With Capacitive Micromachined Ultrasound Transducers (CMUTs) increasingly being used for high intensity, large signal ultrasound applications and several drive methods being proposed, the efficiency of these devices in this operation regime have not been quantitatively evaluated. Since well-known frequency and capacitance-based coupling coefficients definitions are not valid for large signal, nonlinear operation, an energy-based definition should be used. In this paper, an expression for mechanical energy in a CMUT is obtained based on the assumption that CMUT is a linear time varying capacitor in all regimes of operation. This expression is evaluated by the help of an experimentally verified nonlinear CMUT model to define an energy conversion ratio (ECR) which can be considered as a coupling coefficient valid for all regimes of operation. This parameter is validated in the small signal regime and then used to evaluate CMUT performance with various large drive signals. The quantitative modeling results show that CMUTs do not need DC bias to achieve high efficiency large signal transduction: AC only signals at half the operation frequency with amplitudes beyond the collapse voltage can provide efficiencies (ECR) above 0.9 with harmonic content below −25 dB. Based on these results, ECR variation with membrane geometry and parasitic capacitance are given as examples for device optimization. The overall modeling approach is also qualitatively validated by experiments.