bluuebunny/crossref_metadata_2025 huggingface dataset:
A single nucleotide substitution in TaHKT1;5‐D controls shoot Na+ accumulation in bread wheat
Authors: Borjigin Chana , Schilling Rhiannon K. , Bose Jayakumar , Hrmova Maria , Qiu Jiaen , Wege Stefanie , Situmorang Apriadi , Byrt Caitlin , Brien Chris , Berger Bettina , Gilliham Matthew , Pearson Allison S. , Roy Stuart J.
Published: July 2020

Improving salinity tolerance in the most widely cultivated cereal, bread wheat (Triticum aestivum L.), is essential to increase grain yields on saline agricultural lands. A Portuguese landrace, Mocho de Espiga Branca accumulates up to sixfold greater leaf and sheath sodium (Na+) than two Australian cultivars, Gladius and Scout, under salt stress in hydroponics. Despite high leaf and sheath Na+ concentrations, Mocho de Espiga Branca maintained similar salinity tolerance compared to Gladius and Scout. A naturally occurring single nucleotide substitution was identified in the gene encoding a major Na+ transporter TaHKT1;5‐D in Mocho de Espiga Branca, which resulted in a L190P amino acid residue variation. This variant prevents Mocho de Espiga Branca from retrieving Na+ from the root xylem leading to a high shoot Na+ concentration. The identification of the tissue‐tolerant Mocho de Espiga Branca will accelerate the development of more elite salt‐tolerant bread wheat cultivars.
Topical RT1640 treatment effectively reverses gray hair and stem cell loss in a mouse model of radiation‐induced canities
Authors: Anderson Zoya T. , Palmer Joseph W. , Idris Misgana I. , Villavicencio Kyrene M. , Le Giang , Cowart Jaelyn , Weinstein David E. , Harris Melissa L.
Published: July 2020

Gray hair is a visible sign of tissue degeneration during aging. Graying is attributed to dysfunction of melanocyte stem cells (McSCs) that results in depletion of their melanin‐producing progeny. This non‐lethal phenotype makes the hair follicle and its pigment system an attractive model for investigating mechanisms that contribute to tissue aging and therapeutic strategies to combat this process. One potential combination therapeutic is RT1640, which is comprised of two drugs that are known to stimulate hair growth (cyclosporine A [CsA] and minoxidil), along with RT175, a non‐immunosuppressive immunophilin ligand that is implicated in tissue regeneration. Using the ionizing radiation‐induced acute mouse model of hair graying, we demonstrate that RT1640, over CsA alone, promotes regeneration of the hair pigment system during and following treatment. In non‐irradiated mice, RT1640 is also physiologically active and successfully speeds hair growth and expands the McSC pool. It appears that this effect relies on the combined activities of the three drugs within RT1640 to simultaneously activate hair growth and McSCs as RT175 alone was insufficient to induce hair cycling in vivo, yet sufficient to drive the upregulation of the melanogenic program in vitro. This study sets the stage for further investigation into RT1640 and its components in McSC biology and, ultimately, melanocyte hypopigmentary disorders associated with disease and aging.
Bacteriological water quality and biofilm formation in the treatment system of the hemodialysis unit in Tlemcen, Algeria
Authors: Morghad Touhami , Hassaine Hafida , Boutarfi Zakaria , Gaouar Sarah , Bellifa Samia , Meziani Zahera
Published: July 2020

Objective

To evaluate and compare the microbiological quality of osmosis water at the distribution loop, at the dialysis generator inlet and to study the prevalence of biofilm in the tubing.

Methods

Microbiological analysis of 20 water loop samples, 10 water samples were taken at the machine entry and 10 pipe segments from tubing connecting the machines to the loop was done.

Results

The bacterial enumeration results of the loop water vary from 90 to 150 CFU/mL, while the average number of bacteria at the entry of the machines was 182 CFU/mL. The counts of the adhered bacteria in the tubing were worrying with rates ranging from 4.30 to 6.74 Log CFU/ cm2. Fifty percentage of the strains isolated wereBacillus, followed byEnterobacter cloacae23.52%, Staphylococcus, and others such asKlebsiella pneumoniae,Pseudomonas aeruginosa, andAcinetobacter baumanii. More than half of the tubing strains were highly formative of biofilm, 13 strains with medium capacity and 10 were weakly.

Conclusion

This study indicates bacterial water contamination. The formation of a biofilm will certainly harm the effectiveness of the various disinfection methods in this unit. Water quality is influenced not only by the high rate of bacterial colonization, but also differences in standards for dialysis water.
Distribution of contourite drifts on convergent margins: Examples from the Hikurangi subduction margin of New Zealand
Authors: Bailey William S. , McArthur Adam D. , McCaffrey William D.
Published: July 2020

Contourite drift systems form a significant component of the marine clastic sedimentary record. Although contourites form in all tectonic settings, few studies have described their development along convergent margins; such characterization is needed to underpin oceanographic and palaeoenvironmental studies in active settings. This study is the first to document contourite drift development along the Hikurangi subduction margin of New Zealand. Integration of bathymetric, seismic and well data enables five classes of drift to be recognized around the subduction wedge, occurring in three principal associations: (i) an upper slope drift association of giant elongate mounded (ca 150 km long, 50 km wide and up to 1100 m thick) and plastered drifts (ca 300 km long, 8 km wide and <600 m thick), which occurs upon and inboard of a major intrabasinal thrust‐cored high, whose long axis parallels the coast; shallow bottom currents disperse sub‐parallel to this axis; (ii) a spatiotemporally discontinuous association of confined and mounded hybrid drifts (ca 500 m long, <2 km wide and up to 500 m thick) that occurs along the mid‐to‐outer slope domain of the wedge, recording the interaction of along‐slope and downslope currents within trench‐slope basins; and (iii) a trench fill assemblage that implies the passage of abyssal bottom currents across a 40 km reach of the trench‐axial Hikurangi Channel‐levée, with associated modification of the channel form and of overbank sediment waves. The fundamental presence of contourites along this margin appears to depend on the orientation and strength of oceanographic bottom currents. However, drift type and evolution vary depending on the slope gradient and the presence of irregular seafloor topography created by tectonic structures. The documented drifts are generally smaller, less continuous, and develop more intermittently than similar styles of drifts documented on passive margins; this mode of occurrence may be characteristic of contourite development on convergent margins.
The value of preoperative high‐resolution MRI with microscopy coil for facial nonmelanoma skin cancers
Authors: Sheng Meiying , Tang Mengxiao , Lin Wei , Guo Lingchuan , He Wenjun , Chen Weixin , Li Ke , Liu Jianjiang , Xiao Can , Li Yonggang
Published: July 2020

Background

The extent and depth of facial nonmelanoma skin cancers and the involvement of adjacent structures are critical features for surgical planning, but they are difficult to assess clinically. High‐resolution MRI (HR‐MRI) with microscopy coil may facilitate detailed evaluation of skin lesions. The authors performed this prospective study to determine the value of high‐resolution microscopy coil MRI in the preoperative evaluation of nonmelanoma skin cancer.

Materials and Methods

Between October 2018 and August 2019, 16 lesions from fifteen consecutive patients with facial nonmelanoma skin cancer were evaluated using high‐resolution microscopy coil MRI about tumor extent, depth, margins, characteristic, and their spatial relationship with adjacent structures. The preoperative HR‐MRI results were compared with the intraoperative findings and with the histopathology, with special note to the depth of invasion.

Results

Among the 16 lesions, HR‐MRI imaging was found to provide accurate evaluation of tumor extent, depth, and margins and determine whether there was involvement of adjacent structures. The tumor depth measured on HR‐MRI showed good correlation with histopathologic results (CCC: 0.973), and Bland‐Altman analysis finding no significant bias existed between the two measurements. All lesions except one were completely resected with primary excision. Only one lesion required further excision. During follow‐up for 3‐15 months, no tumor recurrence was observed in any case.

Conclusions

HR‐MRI is an accurate, noninvasive imaging technique that can be used as preoperative evaluation tool for facial nonmelanoma skin cancer. It can accurate predict tumor depth, margins, and involvement of structure. The valuable information it provided facilitates surgeons optimize surgical planning.
A COP1‐PIF‐HEC regulatory module fine‐tunes photomorphogenesis in Arabidopsis
Authors: Kathare Praveen K. , Xu Xiaosa , Nguyen Andrew , Huq Enamul
Published: July 2020

Light responses mediated by the photoreceptors play crucial roles in regulating different aspects of plant growth and development. An E3 ubiquitin ligase complex CONSTITUTIVELY PHOTOMORPHOGENIC1 (COP1)1/SUPPRESSOR OF PHYA (SPA), one of the central repressors of photomorphogenesis, is critical for maintaining skotomorphogenesis. It targets several positive regulators of photomorphogenesis for degradation in darkness. Recently, we revealed that basic helix‐loop‐helix factors, HECATEs (HECs), function as positive regulators of photomorphogenesis by directly interacting and antagonizing the activity of another group of repressors called PHYTOCHROME‐INTERACTING FACTORs (PIFs). It was also shown that HECs are partially degraded in the dark through the ubiquitin/26S proteasome pathway. However, the underlying mechanism of HEC degradation in the dark is still unclear. Here, we show that HECs also interact with both COP1 and SPA proteins in darkness, and that HEC2 is directly targeted by COP1 for degradation via the ubiquitin/26S proteasome pathway. Moreover, COP1‐mediated polyubiquitylation and degradation of HEC2 are enhanced by PIF1. Therefore, the ubiquitylation and subsequent degradation of HECs are significantly reduced in both cop1 and pif mutants. Consistent with this, the hec mutants partially suppress photomorphogenic phenotypes of both cop1 and pifQ mutants. Collectively, our work reveals that the COP1/SPA‐mediated ubiquitylation and degradation of HECs contributes to the coordination of skoto/photomorphogenic development in plants.
CURLED LATER1 encoding the largest subunit of the Elongator complex has a unique role in leaf development and meristem function in rice
Authors: Matsumoto Hikari , Yasui Yukiko , Ohmori Yoshihiro , Tanaka Wakana , Ishikawa Tetsuya , Numa Hisataka , Shirasawa Kenta , Taniguchi Yojiro , Tanaka Junichi , Suzuki Yasuhiro , Hirano Hiro‐Yuki
Published: July 2020

The Elongator complex, which is conserved in eukaryotes, has multiple roles in diverse organisms. In Arabidopsis thaliana, Elongator is shown to be involved in development, hormone action and environmental responses. However, except for Arabidopsis, our knowledge of its function is poor in plants. In this study, we initially carried out a genetic analysis to characterize a rice mutant with narrow and curled leaves, termed curled later1 (cur1). The cur1 mutant displayed a heteroblastic change, whereby the mutant leaf phenotype appeared specifically at a later adult phase of vegetative development. The shoot apical meristem (SAM) was small and the leaf initiation rate was low, suggesting that the activity of the SAM seemed to be partially reduced in cur1. We then revealed that CUR1 encodes a yeast ELP1‐like protein, the largest subunit of Elongator. Furthermore, disruption of OsELP3 encoding the catalytic subunit of Elongator resulted in phenotypes similar to those of cur1, including the timing of the appearance of mutant phenotypes. Thus, Elongator activity seems to be specifically required for leaf development at the late vegetative phase. Transcriptome analysis showed that genes involved in protein quality control were highly upregulated in the cur1 shoot apex at the later vegetative phase, suggesting the restoration of impaired proteins probably produced by partial defects in translational control due to the loss of function of Elongator. The differences in the mutant phenotype and gene expression profile between CUR1 and its Arabidopsis ortholog suggest that Elongator has evolved to play a unique role in rice development.
CAFRI‐Rice: CRISPR applicable functional redundancy inspector to accelerate functional genomics in rice
Authors: Hong Woo‐Jong , Kim Yu‐Jin , Kim Eui‐Jung , Kumar Nalini Chandran Anil , Moon Sunok , Gho Yun‐Shil , Yoou Myeong‐Hyun , Kim Sun Tae , Jung Ki‐Hong
Published: July 2020

Rice (Oryza sativa L.) is a staple crop with agricultural traits that have been intensively investigated. However, despite the variety of mutant population and multi‐omics data that have been generated, rice functional genomic research has been bottlenecked due to the functional redundancy in the genome. This phenomenon has masked the phenotypes of knockout mutants by functional compensation and redundancy. Here, we present an intuitive tool, CRISPR applicable functional redundancy inspector to accelerate functional genomics in rice (CAFRI‐Rice; cafri‐rice.khu.ac.kr). To create this tool, we generated a phylogenetic heatmap that can estimate the similarity between protein sequences and expression patterns, based on 2,617 phylogenetic trees and eight tissue RNA‐sequencing datasets. In this study, 33,483 genes were sorted into 2,617 families, and about 24,980 genes were tested for functional redundancy using a phylogenetic heatmap approach. It was predicted that 7,075 genes would have functional redundancy, according to the threshold value validated by an analysis of 111 known genes functionally characterized using knockout mutants and 5,170 duplicated genes. In addition, our analysis demonstrated that an anther/pollen‐preferred gene cluster has more functional redundancy than other clusters. Finally, we showed the usefulness of the CAFRI‐Rice‐based approach by overcoming the functional redundancy between two root‐preferred genes via loss‐of‐function analyses as well as confirming the functional dominancy of three genes through a literature search. This CAFRI‐Rice‐based target selection for CRISPR/Cas9‐mediated mutagenesis will not only accelerate functional genomic studies in rice but can also be straightforwardly expanded to other plant species.
Use of perfusion index to detect hemodynamic changes in endotoxemic pigs
Authors: Endo Yusuke , Miyasho Taku , Imahase Hisashi , Kawamura Yoshio , Sakamoto Yuichiro , Yamashita Kazuto
Published: July 2020

Objective

The perfusion index (PI) derived from plethysmographic signals provides a noninvasive indication of peripheral perfusion. This study aimed to investigate changes in PI and other hemodynamic variables in pigs subjected to endotoxemia.

Design

Prospective experimental study.

Setting

University teaching hospital.

Animals

Twelve healthy pigs weighing a mean (± standard deviation [SD]) of 31.7 ± 2.0 kg.

Interventions

Pigs were divided into control and endotoxin groups (n = 6 each). Endotoxemia was induced by IV infusion of lipopolysaccharide. Heart rate, mean arterial pressure, cardiac index (CI), central venous pressure, systemic vascular resistance index (SVRI), extravascular lung water index (ELWI), Global end‐diastolic volume (GEDV) index, and pulmonary permeability index were measured using a transpulmonary thermodilution monitor in all pigs. PI was measured using a pulse oximeter probe attached to the tail. Pao2, Paco2, and plasma lactate concentration were measured by blood gas analysis. Measurements were taken at baseline (T0). Saline or lipopolysaccharide was then administered for 30 min to all pigs (control or endotoxemia group, respectively), and each parameter was measured every 30 min up to 270 min. Data were analyzed by analysis of variance and Student's t‐tests.

Measurements and Main Results

There were no significant changes in any variables in the control group, but CI, SVRI, PI, ELWI, blood lactate concentration, and Pao2 changed significantly from baseline in the endotoxin group (P < 0.001, P = 0.0048, P < 0.001, P = 0.0064, P < 0.001, and P = 0.0220, respectively). In the endotoxin group, mean (± SD) %PI increased from T0 to 154 ± 34% at T60 (P = .001) and 135 ± 50% at T90 (P =0 .004), which mirrored significant changes in %CI and %SVRI.

Conclusion

The PI may be useful to detect changes in CI and SVRI.
Influence of a purpose‐built frame on the accuracy of computer‐assisted orthopedic surgery of equine extremities
Authors: de Preux Mathieu , Vidondo Beatriz , Koch Christoph
Published: July 2020

Objective

To determine the influence of a purpose‐built frame on the accuracy of screw placement during computer‐assisted orthopedic surgery (CAOS) of the equine extremity.

Study design

Experimental cadaveric study.

Sample population

Twenty‐four paired equine cadaveric limbs obtained from seven horses.

Methods

Three 4.5‐mm cortex screws were inserted in lag technique in three different planes of orientation in the proximal phalanx (P1) by means of CAOS. In the study group (n = 12 limbs), the tracker was anchored on a purpose‐built frame designed to stabilize the extremity. In the control group (n = 12 limbs), a conventional tracker array was used that was anchored directly on P1. The stability of both tracker arrays was assessed during the procedure by using fiducial markers. After screw placement, preoperative and postoperative computed tomographic images were assessed to measure surgical accuracy aberrations (SAA) between the planned and achieved screw position. Descriptive statistics and repeated‐measures analysis of variance were performed to compare SAA measurements between the study and control group.

Results

Both tracker arrays remained consistently stable in all specimens. Mean overall SAA of screw insertion were lower in the study group (0.7 mm; median, 0.5; range 0‐3.4) than in the control group (1.2 mm; median, 0.9; range, 0‐4.2 mm).

Conclusion

The mean SAA achieved in cortex screw placement using CAOS lies within the range of approximately 1 mm. The use of a purpose‐built frame avoided additional drilling of the target bone and improved surgical accuracy compared with the conventional tracker array.

Clinical significance

The purpose‐built frame described in this report can be used to facilitate CAOS in equine orthopedics without compromising surgical accuracy.
Life Cycles of Educational and Development Needs of Employees
Authors: Řezáčová Lenka
Published: July 2020

The paper deals with employee educational and development needs of a concrete organisation. Educational and development needs are defined on the basis of theories of motivation, focus specifically on motivation and barriers in adult education with ambition to discover origin, process and determinants of individual perspective. The aim is to obtain a more comprehensive view of the educational and development needs of employees, which can help motivate adults to education and plan effective corporate education and development.
The impact of damage‐associated molecular patterns on the neurotransmitter release and gene expression in the ex vivo rat carotid body
Authors: Mkrtchian Souren , Kåhlin Jessica , Gómez‐Galán Marta , Ebberyd Anette , Yoshitake Takashi , Schmidt Staffan , Kehr Jan , Hildenborg Malin , Jonsson Fagerlund Malin , Erlandsson Harris Helena , Eriksson Lars I
Published: July 2020

New Findings

What is the central question of this study?

Are carotid bodies (CBs) modulated by the damage‐associated molecular patterns (DAMPs) and humoral factors of aseptic tissue injury?

What are the main findings and their importance?

DAMPs (HMGB1, S100 A8/A9) and blood plasma from rats subjected to tibia surgery, a model of aseptic injury, stimulate the release of neurotransmitters (ATP, dopamine) and TNF‐α from ex vivo rat CBs. All‐thiol HMGB1 mediates upregulation of immune‐related biological pathways. These data suggest regulation of CB function by endogenous mediators of innate immunity.

The glomus cells of carotid bodies (CBs) are the primary sensors of arterial partial O2 and CO2 tensions and moreover serve as multimodal receptors responding also to other stimuli, such as pathogen‐associated molecular patterns (PAMPs) produced by acute infection. Modulation of CB function by excessive amounts of these immunomodulators is suggested to be associated with a detrimental hyperinflammatory state. We have hypothesized that yet another class of immunomodulators, endogenous danger‐associated molecular patterns (DAMPs), released upon aseptic tissue injury and recognized by the same pathogen recognition receptors as PAMPs, might modulate the CB activity in a fashion similar to PAMPs. We have tested this hypothesis by exposing rat CBs to various DAMPs, such as HMGB1 (all‐thiol and disulfide forms) and S100 A8/A9 in a series of ex vivo experiments that demonstrated the release of dopamine and ATP, neurotransmitters known to mediate CB homeostatic responses. We observed a similar response after incubating CBs with conditioned blood plasma obtained from the rats subjected to tibia surgery, a model of aseptic injury. In addition, we have investigated global gene expression in the rat CB using an RNA sequencing approach. Differential gene expression analysis showed all‐thiol HMGB1‐driven upregulation of a number of prominent pro‐inflammatory markers including Il1α and Il1β. Interestingly, conditioned plasma had a more profound effect on the CB transcriptome resulting in inhibition rather than activation of the immune‐related pathways. These data are the first to suggest potential modulation of CB function by endogenous mediators of innate immunity.
Aliento, aire y viento: representaciones de la territorialización del cuerpo
Authors: Serna Gallego Daniela , Castañeda López Libia Alejandra
Published: July 2020

Este artículo aborda los videos de los artistas Rivane Neuenschwander y Cao Guimarães Inventário das pequenas mortes (Sopro) (2000) y O inquilino (2010), y la película El premio (2011) de Paula Markovitch como puntos de partida para reflexionar sobre la vida, la creación, el cuerpo y su territorialización. Para ello, se plantea el concepto de aire como materia y metáfora de una energía creadora, y el concepto de esferas como formas alegóricas y abstracciones espaciales de territorios en constante disputa. A través de una metodología comparativa, se retoman los aportes teóricos de Peter Sloterdijk para discutir las nociones de espacio interior y espacio exterior, y de Gaston Bachelard para analizar la dimensión espacial desde la fenomenología de lo redondo y la idea del aire como elemento de creación. Por su parte, la noción de biopolítica y el papel de la esfera privada y pública se analiza a través del concepto de nuda vida de Giorgio Agamben, y el cuerpo femenino como territorio de disputa política a través del concepto de vulnerabilidad de Judith Butler y de Carol Arcos. Este análisis formal, narrativo, crítico y teórico relaciona las formas del aire con las tres obras audiovisuales, lo cual evidencia desde una lectura estética las tensiones que constituyen el cuerpo tanto físico como político, y su constante pendular entre el adentro y el afuera, entre lo público y lo privado, entre la vida y la muerte.
El viento en la escollera: aire y agua en la música popular uruguaya
Authors: Fornaro Bordolli Marita
Published: July 2020

El artículo propone un análisis de la presencia del aire en la música y el teatro musical popular de Uruguay, en especial de las décadas de 1980 y de 1990. Interesa establecer cómo las metáforas y alegorías del aire se encuentran con el agua física y simbólica de la bahía de Montevideo, ciudad que fue el puerto natural por excelencia del Atlántico Sur durante la Colonia y hasta hoy es punto de encuentros de tradiciones. A partir de la propuesta de Steven Connor en Matter of Air (2010), se atiende a la presencia simbólica del aire; se integran elementos de la antropología de las emociones y del análisis desde la retórica de las diversas artes. Para el caso de las canciones, se analizan los textos y su relación con la música, en especial aquellos rasgos vinculados con el contenido literario (características de la emisión vocal, instrumentación y arreglos), y en el caso de la murga, género de teatro musical carnavalesco, la vinculación entre literatura, música, coreografías, vestuario, escenografía y maquillaje. El análisis se profundiza para el espectáculo El planeador de la escollera Sarandí, producido por la murga Curtidores de hongos durante el carnaval montevideano de 2005, en que texto literario y vestuario se complementan en la producción de sentido, y para dos canciones interpretadas por Eduardo Darnauchans, figura relevante de la música popular uruguaya. Se incluye también una breve presentación de otras canciones que elaboran metafóricamente el paisaje visual y sonoro de la ciudad, con el aire como centro temático.
Properties and Corrosion Behavior of Chromium and Vanadium Carbide Composite Coatings Produced on Ductile Cast Iron by Thermoreactive Diffusion Technique
Authors: Günen Ali , Kalkandelen Müge , Karahan İsmail Hakkı , Kurt Bülent , Kanca Erdoğan , Gök Mustafa Sabri , Serdar Karakaş Mustafa
Published: July 2020

Ductile iron (DI) owes many of its attractive mechanical properties to the graphite nodules in its structure. However, since galvanic coupling can occur between the graphite nodules and the matrix in aggressive environments, these nodules can, at the same time, reduce its corrosion resistance. In this study, composite carbide coatings were grown on the surface of GGG-80 using the thermoreactive diffusion (TRD) process. The process was carried out at 900, 1000, and 1100 °C for 1 h using nanosized Fe-V and Fe-Cr powders. The coatings were characterized by X-ray diffractometry (XRD), two-dimensional profilometry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), and microhardness tests. The corrosion behavior of the coatings were evaluated in three different solutions (3.5 wt% NaCl, 5 wt% H2SO4, and 5 wt% HNO3) using electrochemical open-circuit potential (OCP) and potentiodynamic polarization measurements. Microstructures and hardness tests showed that the nodular graphite in the surface was dissolved at the TRD process temperatures and that a coating of 12–36 µm thickness and 2461–3200 HV0.05 hardness was obtained. The corrosion resistance of the composite coating was up to 10, 33.5, and 75 times higher than the uncoated GGG-80 in NaCl, H2SO4, and HNO3, respectively. The improvement in corrosion resistance was a direct result of the formation of complex carbides and the elimination of graphite nodules in the surface of the alloy.
Multifunctional Fused Deposition Modeled Acrylonitrile Butadiene Styrene-Based Structures With Embedded Conductive Channels
Authors: Youssef George , Smilo Jordan , Blourchian Aryan , Huynh Nha Uyen , Karapetian Arbi V.
Published: July 2020

The applicability of additive manufacturing (AM) continues to expand because of research and development efforts in industrial, academic, and governmental institutions. The lure of additive manufacturing lies in the quick time-to-market and ability to produce parts and components with high degrees of topographical complexity empowered by the layer-by-layer production approach. One challenge that is attracting a significant amount of attention is improving the multi-functionality of additively manufactured parts, as enabling multi-functionality will result in transitioning AM to a broader application domain. The objective of this paper is to report novel developments that improve the functionality of polymer-based parts by adding electrical conductivity and fluid management to the existing load-bearing capabilities. A space structure was 3D-printed using acrylonitrile butadiene styrene (ABS) with embedded internal channels throughout the entire structure and then sealed using an acetone-diluted epoxy. The inner surfaces of the embedded channels of the sealed structure were then metallized using an electroless silver-coating process; these processes were found to be robust and independent of the inner diameter and length of the structure. The electromechanical performance of the structure was verified by applying mechanical loading while monitoring the change in electrical resistivity. The latter was found to remain nearly constant up to the point of ultimate mechanical failure. Finite element modeling was used to identify the areas of structural weaknesses and assist in elucidating the failure modes. The results were found to be in good agreement with the experimental data.
The Effect of Texture Floor Profile on the Lubricant Film Thickness in a Textured Hard-On-Soft Bearing With Relevance to Prosthetic Hip Implants
Authors: Allen Quentin , Raeymaekers Bart
Published: July 2020

Polyethylene wear debris limits the longevity of prosthetic hip implants. We design a pattern of axisymmetric texture features to increase hydrodynamic pressure and lubricant film thickness and, thus, reduce solid-on-solid contact, friction, and wear in hard-on-soft prosthetic hip implant bearings. Specifically, we study the effect of the texture floor profile on the lubricant film thickness using a soft elastohydrodynamic lubrication model. We compute the optimum texture parameters that maximize the lubricant film thickness for different texture floor profiles, as a function of bearing operating conditions. Flat texture floor profiles create thicker lubricant films than sloped or curved texture floor profiles for their respective optimum texture design parameters. We find that the texture feature volume is the most important parameter in terms of maximizing the lubricant film thickness, because a linear relationship exists between the texture feature volume with optimum texture parameters and the corresponding optimum lubricant film thickness, independent of the texture floor profile.
Improved Layouts and Performance of Single- and Double-Flash Steam Geothermal Plants Generated by the Heatsep Method
Authors: Manente Giovanni , Lazzaretto Andrea
Published: July 2020

Single- and double-flash steam power plants are commonly used in the utilization of high enthalpy liquid-dominated geothermal resources. In these plants, the expansion line in the wet steam region results in significant penalties of turbine isentropic efficiency and power output. Accordingly, the “self-superheating” and “interstage heating” plant modifications have been recently proposed in the literature, where the saturated steam at turbine inlet is superheated by using the heat of the geothermal liquid, which is cooled before the flashing process. In this study, the aforementioned and additional new flash steam plant layouts are generated by using a systematic method, called Heatsep, for the optimum design of energy systems. All the thermal connections between consecutive basic plant components are “cut” to let these temperatures vary and in turn generate additional hot and cold streams, which are combined to enhance the overall performance of the system. It is demonstrated that the single-flash plant with self-superheating is simply obtained by cutting two out of five thermal links. In the double-flash plant, the higher number of components allows for a higher number of thermal cuts and heat integration options. Unlike the existing literature, the maximum power output is not constrained by a predefined heat transfer network. The optimization results show that the maximum power output of the novel single- and double-flash steam plants exceeds by 5.5–9.2% and 3.9–7.7% the maximum attainable by the corresponding traditional plants without internal heat integration.
Comparison of Various Blade Profiles in a Two-Blade Conventional Savonius Wind Turbine
Authors: Hassanzadeh Rahim , Mohammadnejad Milad , Mostafavi Sajad
Published: July 2020

Savonius turbines are one of the old and cost-effective turbines which extract the wind energy by the drag force. Nowadays, they use in urban areas to generate electricity due to their simple structure, ease of maintenance, and acceptable power output under a low wind speed. However, their efficiency is low and the improvement of their performance is necessary to increase the total power output. This paper compares four various blade profiles in a two-blade conventional Savonius wind turbine. The ratios of blade diameter to the blade depth of s/d = 0.3, 0.5, 0.7, and 1 are tested under different free-wind speeds of 3, 5, and 7 m/s and tip speed ratios (TSRs) in the range from 0.2 to 1.2. It is found that the profile of blades in a Savonius rotor plays a considerable role in power characteristics. Also, regardless of blades profile and free-wind speed, the maximum power coefficient develops in TSR = 0.8. In addition, increasing the free-wind speed enhances the rotor performance of all cases under consideration. Finally, it is revealed that the rotor with s/d = 0.5 provides maximum power coefficients in all free-wind speeds and TSR values among the rotors under consideration, whereas the rotor with s/d = 1 is the worth cases.
Heat Transfer and Secondary Flow Characteristics in a Horizontally Round Pipe for Cooling a Scramjet Combustor by Supercritical n-Decane
Authors: Li Yong , Chen Youqian , Xie Gongnan , Sunden Bengt
Published: July 2020

To figure out the abnormal flow characteristics and thermal performance of supercritical fluids, some detailed information of supercritical pressure n-decane flowing in a horizontally round pipe is studied in terms of secondary flow induced by the huge density change or buoyancy force. According to an evaluation of turbulence models, the shear stress transport k–ω is suitable to execute the case of horizontal flow. It is observed that the temperature distributions between the upper wall region and the lower wall region are asymmetric and the location of the maximum buoyancy force coincided with the position of Tpc (pseudo-critical temperature). The generation of a rotating flow arising from the heated wall determines the occurrence of heat transfer deterioration (HTD). In the boom stage of the HTD phenomenon, a dead zone that is close to the upper wall was formed due to the influence of vortices. In contrast, the maximum buoyancy force is located in the core flow zone and it forces the fluid in the mainstream to participate in the cooling process of the heated wall. In addition, the dead zone in the vicinity of the upper wall is broken. This is the main reason why heat transfer deterioration could be inhibited effectively.
Determination of Main-Term and Cross-Term Gas Diffusivities in Heavy Oil Systems Considering Local Oil Swelling Effect
Authors: Jang Hyun Woong , Yang Daoyong
Published: July 2020

To inject gas into a heavy oil reservoir, molecular diffusion of the dissolved gas into heavy oil is one of the crucial mechanisms to lower its viscosity while swelling the diluted oil. Various efforts have been made to predict the diffusivity of such gas dissolved in heavy oil with or without considering the oil swelling. Practically, the oil swelling is always considered in an excessively simplified manner so that such swelling is not able to exhibit its true effect on the estimated diffusivity. In most studies where the oil swelling is considered, the liquid-phase hydrocarbon is assumed to swell equally at every location because the height of liquid-phase in a diffusion vessel is simply extended proportionally to the oil swelling direction. Such a proportional swell is often realized during numerical solutions by uniformly extending the numerical cells, regardless of the amount of dissolved gas contained in each of them. In addition, no studies have been made to examine the contribution of one gas over the other for a gas mixture-liquid system. In this study, a pragmatic approach is proposed to determine the main- and cross-term diffusivities of gas–liquid systems considering local swelling effect. More specifically, diffusivities of CO2 and a CO2–C3H8 mixture in a Lloydminster heavy oil are respectively estimated by implementing the finite difference approximation (FDA) with the face-centered explicit scheme. For the CO2–C3H8 mixture, the individual diffusivity of each gas in the mixture is firstly computed independent of the other gas in the mixture. Then, the cross-term diffusivity is included to verify the effect of the other gas in heavy oil for the diffusion of one gas, while the local oil swelling is implemented during the estimation of the individual gas diffusivities. It is found that the obtained diffusivities of pure CO2 and each individual component of the CO2–C3H8 mixture in the Lloydminster heavy oil are reasonable and accurate to reproduce the measured oil swelling factors obtained from the dynamic volume analysis (DVA) tests.
Biochar From Cocoa Shell Pyrolysis: Potential Sorbent for CO2 Capture
Authors: Najafabadi Hamed Abedini , Ozalp Nesrin , Davis Richard A.
Published: July 2020

Biochar produced from slow pyrolysis of cocoa shells was studied as a sorbent for CO2 capture. Three cocoa shell samples obtained from Papua New Guinea, Peru, and Colombia were studied. Thermogravimetric analysis showed that the first three stages of degradation were quite similar for different cocoa shell sources. However, the fourth stage was different, which could be due to the different lignin content in the cocoa shell sources. Chemical analysis showed that the cocoa shell biochar had a lower content of carbon and oxygen, and a higher content of magnesium, potassium, and calcium compared with the cocoa shell. CO2 uptake performance of the cocoa shell biochar was examined and compared with a commercial activated carbon using a thermogravimeter at atmospheric pressure and ambient temperature. The final CO2 uptake after 30 min was slightly higher for cocoa shell biochar. However, activated carbon had a faster adsorption response, and it approached equilibrium faster than the cocoa shell biochar. This could be due to differences in particle size, pore structure, and surface area of the activated carbon which allows the CO2 to be adsorbed easily in its porous structure. A pseudo-second-order model of kinetics fits the CO2 adsorption behavior of cocoa shell biochar and activated carbon indicating that the rate-limiting step is chemical adsorption. Furthermore, the stability of the cocoa shell sorbent was confirmed over four adsorption/desorption cycles. By considering the simplicity of the production process and efficiency of CO2 adsorption, cocoa shell biochar can be considered a good option for CO2 capture.
Mechanics of Regular-Shape Nanomeshes for Transparent and Stretchable Devices
Authors: Vinnikova Sandra , Fang Hui , Wang Shuodao
Published: July 2020

Open nanomesh structures with nano/micro-scale geometric dimensions are important candidates for transparent, soft, and stretchable microelectrodes. This study developed analytical and numerical mechanics models for three types of nanomeshes that consist of regular polygons and straight traces. The analytical models described the transparency, effective stiffness, and stretchability of the nanomeshes and agree with the finite element analysis. The mechanical performances of the nanomeshes are compared based on the same level of transparency. The validated analytical expressions provide convenient guidelines for designing the nanomeshes to have levels of transparency and mechanical properties suitable for bio-integrated applications.
Probabilistic Finite Element Analysis of Cooled High-Pressure Turbine Blades—Part A: Holistic Description of Manufacturing Variability
Authors: Högner Lars , Voigt Matthias , Mailach Ronald , Meyer Marcus , Gerstberger Ulf
Published: July 2020

Modern high-pressure turbine (HPT) blade design stands out due to its high complexity comprising three-dimensional blade features, multipassage cooling system (MPCS), and film cooling to allow for progressive thermodynamic process parameters. During the last decade, probabilistic design approaches have become increasingly important in turbomachinery to incorporate uncertainties such as geometric variations caused by manufacturing scatter and deterioration. Within this scope, the first part of this two-part article introduces parametric models for cooled turbine blades that enable probabilistic finite element (FE) analysis taking geometric variability into account to aim at sensitivity and robustness evaluation. The statistical database is represented by a population of more than 400 blades whose external geometry is captured by optical measurement techniques and 34 blades that are digitized by computed tomography (CT) to record the internal geometry and the associated variability, respectively. Based on these data, parametric models for airfoil, profiled endwall (PEW), wedge surface (WSF), and MPCS are presented. The parametric airfoil model that is based on the traditional profile theory is briefly described. In this regard, a methodology is presented that enables to adapt this airfoil model to a given population of blades by means of Monte Carlo-based optimization. The endwall variability of hub and shroud are parametrized by radial offsets that are applied to the respective median endwall geometry. WSFs are analytically represented by planes. Variations of the MPCS are quantified based on the radial distribution of cooling passage centroids. Thus, an individual MPCS can be replicated by applying adapted displacement functions to the core passage centroids. For each feature that is considered within this study, the accuracy of the parametric model is discussed with respect to the variability that is present in the investigated blade population and the measurement uncertainty. Within the scope of the second part of this article, the parametric models are used for a comprehensive statistical analysis to reveal the parameter correlation structure and probability density functions (PDFs). This is required for the subsequent probabilistic finite element analysis involving real geometry effects.
Deficiencies in the Spalart–Allmaras Turbulence Model for the Prediction of the Stability Boundary in Highly Loaded Compressors
Authors: Moreno Jose , Dodds John , Stapelfeldt Sina , Vahdati Mehdi
Published: July 2020

Reynolds-averaged Navier–Stokes (RANS) equations are employed for aerodynamic and aeroelastic modeling in axial compressors. Their solutions are highly dependent on the turbulence models for closure. The main objective of this work is to assess the widely used Spalart–Allmaras model suitability for high-speed compressor flows. For this purpose, an extensive investigation of the sources of uncertainties in a high-speed multi-stage compressor rig was carried out. The grid resolution near the casing end wall, which affects the tip leakage flow and casing boundary layer, was found to have a major effect on the stability limit prediction. Refinements in this region led to a stall margin loss prediction. It was found that this loss was exclusively due to the destruction term in the SA model.
Deep Neural Network-Based Screening Model for COVID-19-Infected Patients Using Chest X-Ray Images
Authors: Singh Dilbag , Kumar Vijay , Yadav Vaishali , Kaur Manjit
Published: July 2020

There are limited coronavirus disease 2019 (COVID-19) testing kits, therefore, development of other diagnosis approaches is desirable. The doctors generally utilize chest X-rays and Computed Tomography (CT) scans to diagnose pneumonia, lung inflammation, abscesses, and/or enlarged lymph nodes. Since COVID-19 attacks the epithelial cells that line our respiratory tract, therefore, X-ray images are utilized in this paper, to classify the patients with infected (COVID-19 [Formula: see text]ve) and uninfected (COVID-19 [Formula: see text]ve) lungs. Almost all hospitals have X-ray imaging machines, therefore, the chest X-ray images can be used to test for COVID-19 without utilizing any kind of dedicated test kits. However, the chest X-ray-based COVID-19 classification requires a radiology expert and significant time, which is precious when COVID-19 infection is increasing at a rapid rate. Therefore, the development of an automated analysis approach is desirable to save the medical professionals’ valuable time. In this paper, a deep convolutional neural network (CNN) approach is designed and implemented. Besides, the hyper-parameters of CNN are tuned using Multi-objective Adaptive Differential Evolution (MADE). Extensive experiments are performed by considering the benchmark COVID-19 dataset. Comparative analysis reveals that the proposed technique outperforms the competitive machine learning models in terms of various performance metrics.
An Efficient Particle Swarm Optimization with Multidimensional Mean Learning
Authors: Li Wei , Meng Xiang , Huang Ying , Yang Junhui
Published: July 2020

Particle swarm optimization (PSO) algorithm is a stochastic and population-based optimization algorithm. Its traditional learning strategy is implemented by updating the best position using the particle’s own historical best experience and its neighborhood’s best experience to find the optimal solution of the problem. However, the learning strategy is ineffective when dealing with highly complex problems. In this paper, a particle swarm optimization algorithm based on a multidimensional mean learning strategy is proposed. In this algorithm, an opposition-based learning strategy is utilized to initialize the population to enhance the exploitation capability. Furthermore, the historical best positions of all the particles are reconstructed in a vertical crossover manner that is based on the mean information of multiple optimal dimensions to generate the guiding particles. Additionally, an improved inertia weight is used to further guide all the particle movements to balance the capability of the proposed algorithm for global exploration and local exploitation. The proposed algorithm is tested on 12 benchmark functions and is compared with some well-known PSO algorithms. The experimental results show that the proposed algorithm obtains more competitive optimal solution compared with other PSO algorithms when solving high-dimensional complex problems.
Single-Image Super-Resolution based on Steering Kernel and Gaussian Process Regression
Authors: Wang Haijun , Nie Yalin , Yan Ben
Published: July 2020

Single-image super-resolution (SR) imaging is a fundamental problem in image processing; it is important in entertainment, video surveillance, remote sensing, medicine, and other fields. Gaussian process regression (GPR) is a kernel method whereby nonlinear mapping relationships in data can be learned. However, the traditional Gaussian kernel function used in GPR is isotropic and fails to capture complex image structures. Accordingly, the structure information of image patches, termed steering kernel coefficients (SKCs), is extracted by a steering kernel function. After patches with similar structure are clustered according to their SKCs, an anisotropic automatic-relevance-determination (ARD) kernel function is used to learn the model for each cluster. Aiming at learning a structure-sensitive GPR model, we integrate the SKCs and ARD to achieve improved performance for GPR-based SR. Experiments demonstrate that the proposed method can effectively capture the structural relevance of image patches and yield promising results.