bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of hot water extract of Curcuma longa on human epidermal keratinocytes in vitro and skin conditions in healthy participants: A randomized, double‐blind, placebo‐controlled trial
Authors: Asada Kazuki , Ohara Tatsuya , Muroyama Koutarou , Yamamoto Yoshihiro , Murosaki Shinji
Published: February 2019

Background

Curcuma longa has been reported to have anti‐inflammatory effects. Skin inflammation impairs skin functions.

Objectives

Our aim was to investigate the effect of a hot water extract of C longa (WEC) on skin conditions in cell studies using keratinocytes and in clinical trials.

Methods

We measured proinflammatory cytokine levels in ultraviolet B‐irradiated keratinocytes in the presence or absence of WEC. The effects of WEC on hyaluronan production in keratinocytes were also determined. In a randomized, double‐blind, placebo‐controlled trial, 47 healthy participants were assigned to 8‐week intervention groups with daily intakes of WEC with or without curcumin or a placebo. The water content and transepidermal water loss in the face and minimal erythema dose on the back after ultraviolet B irradiation were evaluated every 4 weeks.

Results

Hot water extract of C longa significantly inhibited increases in ultraviolet B‐induced tumor necrosis factor α and interleukin 1β at the mRNA and protein levels. WEC also significantly increased hyaluronan production from nonstimulated keratinocytes. In the randomized, double‐blind, placebo‐controlled trial, increases from baseline in the water content of the face were significantly greater at weeks 4 and 8 in the WEC group, but not in the WEC + curcumin group, than in the placebo group. There were no significant differences in transepidermal water loss and minimal erythema dose among the groups.

Conclusions

The cell studies confirmed that WEC has anti‐inflammatory effects and augments hyaluronan production in the skin. The results of clinical trials suggest that WEC may be useful for moisturizing facial skin.

Trial registration

UMIN Clinical Trials Registry 000028510. Retrospectively registered.
Costly Information Acquisition, Social Networks, and Asset Prices: Experimental Evidence
Authors: HALIM EDWARD , RIYANTO YOHANES E. , ROY NILANJAN
Published: February 2019

We design an experiment to study the implications of information networks for incentives to acquire costly information, market liquidity, investors' earnings, and asset price characteristics in a financial market. Social communication crowds out information production as a result of an agent's temptation to free ride on the signals purchased by her neighbors. Although information exchange among traders increases trading volume, improves liquidity, and enhances the ability of asset prices to reflect the available information in the market, it fails to improve price informativeness. Net earnings and social welfare are higher with information sharing due to reduced acquisition of costly signals.
Intra‐individual stability of NREM sleep quantitative EEG measures in obstructive sleep apnea
Authors: Poon Joseph J. Y. , Chapman Julia L. , Wong Keith K. H. , Mullins Anna E. , Cho Garry , Kim Jong W. , Yee Brendon J. , Grunstein Ronald R. , Marshall Nathaniel S. , D'Rozario Angela L.
Published: March 2019

Electroencephalography is collected routinely during clinical polysomnography, but is often utilised to simply determine sleep time to calculate apnea–hypopnea indices. Quantitative analysis of these data (quantitative electroencephalogram) may provide trait‐like information to predict patient vulnerability to sleepiness. Measurements of trait‐like characteristics need to have high test–retest reliability. We aimed to investigate the intra‐individual stability of slow‐wave (delta power) and spindle frequency (sigma power) activity during non‐rapid eye movement sleep in patients with obstructive sleep apnea. We recorded sleep electroencephalograms during two overnight polysomnographic recordings in 61 patients with obstructive sleep apnea (median days between studies 47, inter‐quartile range 53). Electroencephalograms recorded at C3‐M2 derivation were quantitatively analysed using power spectral analysis following artefact removal. Relative delta (0.5–4.5 Hz) and sigma (12–15 Hz) power during non‐rapid eye movement sleep were calculated. Intra‐class correlation coefficients and Bland–Altman plots were used to assess agreement between nights. Intra‐class correlation coefficients demonstrated good‐to‐excellent agreement in the delta and sigma frequencies between nights (intra‐class correlation coefficients: 0.84, 0.89, respectively). Bland–Altman analysis of delta power showed a mean difference close to zero (−0.4, 95% limits of agreement −9.4, 8.7) and no heteroscedasticity with increasing power. Sigma power demonstrated heteroscedasticity, with reduced stability as sigma power increased. The mean difference of sigma power between nights was close to zero (0.1, 95% limits −1.6, 1.8). We have demonstrated the stability of slow‐wave and spindle frequency electroencephalograms during non‐rapid eye movement sleep within patients with obstructive sleep apnea. The electroencephalogram profile during non‐rapid eye movement sleep may be a useful biomarker for predicting vulnerability to daytime impairment in obstructive sleep apnea and responsiveness to treatment.
Some aspects of the biology and development of Ichthyophis glutinosus (Amphibia: Gymnophiona)
Authors: BRECKENRIDGE W. R. , NATHANAEL SHIRANI , PEREIRA LIONEL
Published: March 2019

Specimens of Ichthyophis glutinosus hatched in the laboratory were studied over a three‐year period. Larval mortality during the early period of development was very high, with only three out of an initial number of 19 larvae surviving to the present. The aquatic larvae change gradually into terrestrial burrowing forms within 48–50 weeks after hatching. The larval condition is characterized morphologically by a more rounded head with sense organs, prominent eyes and a tail fin, whereas the post‐metamorphic form has a more pointed head, reduced eyes, tentacles, nuchal collars and yellow lateral stripes. Examination by light microscopy shows the larval skin to be thinner than adult skin and lacking a keratinized stratum corneum and calcified scales. Leydig cells found only in larval skin elaborate a secretion which is a periodate reactive acidic mucosubstance with a protein component. They decrease in number and disappear at metamorphosis. Length and weight increases of the larva arc gradual but after metamorphosis arc marked by weight increases being greater than increase in length. Metamorphosis itself is gradual, spread over an appreciably long period, and is not as dramatic as in anurans.
A variation of the Azéma martingale and drawdown options
Authors: Dassios Angelos , Lim Jia Wei
Published: March 2019

In this paper, we derive a variation of the Azéma martingale using two approaches—a direct probabilistic method and another by projecting the Kennedy martingale onto the filtration generated by the drawdown duration. This martingale links the time elapsed since the last maximum of the Brownian motion with the maximum process itself. We derive explicit formulas for the joint densities of , which are the first time the drawdown period hits a prespecified duration, the value of the Brownian motion, and the maximum up to this time. We use the results to price a new type of drawdown option, which takes into account both dimensions of drawdown risk—the magnitude and the duration.
Balance‐of‐payments‐constrained cyclical growth with distributive class conflicts and productivity dynamics
Authors: Nishi Hiroshi
Published: March 2019

This study builds a dynamic balance‐of‐payments‐constrained model that incorporates the endogenous determination of the economic growth rate, conflictive wage/price distribution and employment rate. The wages, commodity prices and employment rate are determined by the profit squeeze effect and labour‐saving technical change. The relative strength of these two effects generates different outcomes for the transitional dynamics and comparative statics analysis. Particularly, the model shows stability, instability and cyclical nature, the latter of which concurs with the evidence reported by previous empirical studies.
Valuing Cooperation and Constructive Controversy: A Tribute to David W. Johnson
Authors: Tjosvold Dean , Druckman Daniel , Johnson Roger T. , Smith Karl A. , Roseth Cary
Published: February 2019

The International Association of Conflict Management awarded David Johnson the Jeffrey Rubin Theory‐to‐Practice Award for professional achievement in 2010. To extend this recognition of David, Negotiation and Conflict Management Research invited us to publish this tribute. We begin with Dean Tjosvold's discussion of David's career. Daniel Druckman describes David's research on constructive controversy and team performance. Roger Johnson outlines how David and he laid the foundations of cooperative learning. Karl Smith describes the development of intellectual disagreement to promote decision‐making. Cary Roseth shows the persistence and skill needed for David's meta‐analyses on the effects of cooperation and competition on learning. Finally, David responds to three questions developed by the contributors.
Pharmacologic effects of naldemedine, a peripherally acting μ‐opioid receptor antagonist, in in vitro and in vivo models of opioid‐induced constipation
Authors: Kanemasa Toshiyuki , Koike Katsumi , Arai Tohko , Ono Hiroko , Horita Narumi , Chiba Hiroki , Nakamura Atsushi , Morioka Yasuhide , Kihara Tsuyoshi , Hasegawa Minoru
Published: March 2019

Background

Naldemedine (S‐297995) is a peripherally acting μ‐opioid receptor antagonist developed as a once‐daily oral drug for opioid‐induced constipation (OIC) in adults with chronic noncancer or cancer pain. This study characterized the pharmacological effects of naldemedine in vitro and in vivo.

Methods

The binding affinity and antagonist activity of naldemedine against recombinant human μ‐, δ‐, and κ‐opioid receptors were assayed in vitro. Pharmacologic effects of naldemedine were investigated using animal models of morphine‐induced inhibition of small and large intestinal transit, castor oil‐induced diarrhea, antinociception, and morphine withdrawal.

Key Results

Naldemedine showed potent binding affinity and antagonist activities for recombinant human μ‐, δ‐, and κ‐opioid receptors. Naldemedine significantly reduced opioid‐induced inhibition of small intestinal transit (0.03‐10 mg kg−1; P < 0.05) and large intestinal transit (0.3‐1 μmol L−1; P < 0.05). Naldemedine (0.03‐1 mg kg−1) pretreatment significantly reversed the inhibition of castor oil‐induced diarrhea by subcutaneous morphine (P < 0.01). Naldemedine (1‐30 mg kg−1) pretreatment (1 or 2 hours) did not alter the analgesic effects of morphine in a model measuring the latency of a rat to flick its tail following thermal stimulation. However, a significant delayed reduction of the analgesic effect of morphine was seen with higher doses of naldemedine (10‐30 mg kg−1). Some centrally mediated and peripherally mediated withdrawal signs in morphine‐dependent rats were seen with naldemedine doses ≥3 and ≥0.3 mg kg−1, respectively.

Conclusions & Inferences

Naldemedine displayed potent binding affinity to, and antagonistic activity against, μ‐, δ‐, and κ‐opioid receptors. Naldemedine tempered OIC in vivo without compromising opioid analgesia.
Williams syndrome
Authors: Twite Mark D. , Stenquist Scott , Ing Richard J.
Published: February 2019

Williams syndrome affects approximately one in 10 000 people and is caused by the deletion of genes on chromosome 7q11.23 which code for elastin. The phenotypic appearance of people with Williams syndrome is well characterized, but there continues to be new genetic and therapeutic discoveries. Patients with Williams syndrome have increased morbidity and mortality under sedation and anesthesia, largely as a result of cardiovascular abnormalities. This review article focuses on new information about Williams syndrome and outlines a structured approach to patients with Williams syndrome in the perioperative period.
Reducing expression of a nitrate‐responsive bZIP transcription factor increases grain yield and N use in wheat
Authors: Yang Junbo , Wang Meiyue , Li Wenjing , He Xue , Teng Wan , Ma Wenying , Zhao Xueqiang , Hu Mengyun , Li Hui , Zhang Yijing , Tong Yiping
Published: February 2019

Nitrogen (N) plays critical role in plant growth; manipulating N assimilation could be a target to increase grain yield and N use. Here, we show that ABRE‐binding factor (ABF)‐like leucine zipper transcription factor TabZIP60 mediates N use and growth in wheat. The expression of TabZIP60 is repressed when the N‐deprived wheat plants is exposed to nitrate. Knock down of TabZIP60 through RNA interference (RNAi) increases NADH‐dependent glutamate synthase (NADH‐GOGAT) activity, lateral root branching, N uptake and spike number, and improves grain yield more than 25% under field conditions, while overexpression of TabZIP60‐6D had the opposite effects. Further investigation shows TabZIP60 binds to ABRE‐containing fragment in the promoter of TaNADH‐GOGAT‐3B and negatively regulates its expression. Genetic analysis reveals that TaNADH‐GOGAT‐3B overexpression overcomes the spike number and yield reduction caused by overexpressing TabZIP60‐6D. As such, TabZIP60‐mediated wheat growth and N use is associated with its negative regulation on TaNADH‐GOGAT expression. These findings indicate that TabZIP60 and TaNADH‐GOGAT interaction plays important roles in mediating N use and wheat growth, and provides valuable information for engineering N use efficiency and yield in wheat.
Elevated root nicotianamine concentrations are critical for Zn hyperaccumulation across diverse edaphic environments
Authors: Uraguchi Shimpei , Weber Michael , Clemens Stephan
Published: February 2019

The metallophyte Arabidopsis halleri thrives across an extremely broad edaphic range. Zn hyperaccumulation is found on soils differing in available Zn by up to six orders of magnitude, raising the question as to whether a common set of mechanisms confers this species‐wide ability. Elevated root concentrations of the metal chelator nicotianamine due to strong constitutive expression of AhNAS2 are important for hyperaccumulation. In order to analyse the relevance of AhNAS2 under more natural conditions representing a range of metalliferous and nonmetalliferous habitats, we collected soil at eight different A. halleri sites and cultivated wild‐type and AhNAS2‐RNAi lines in these soils. AhNAS2 transcript abundance and root nicotianamine concentrations in wild‐type plants were barely influenced by soil metal concentrations. The RNAi effect was fully expressed in different soils. Zn hyperaccumulation in AhNAS2‐silenced lines was significantly reduced in seven soils. Root‐to‐shoot translocation of Cd, Mn, Cu, Ni, and Co was also affected by AhNAS2 silencing, albeit to a lower extent and less consistently. Leaf Fe levels were unaffected by AhNAS2 knockdown. Results demonstrate that elevated nicotianamine production in roots of A. halleri is a Zn hyperaccumulation factor regardless of the edaphic environment, that is, contributes to Zn hyperaccumulation in soils with contrasting Zn availability.
Genome‐wide DNA methylation investigation of glucocorticoid exposure within buccal samples
Authors: Braun Patricia R. , Tanaka‐Sahker Mai , Chan Aubrey C. , Jellison Sydney S. , Klisares Mason J. , Hing Benjamin W. , Shabbir Yaseen , Gaul Lindsey N. , Nagahama Yasunori , Robles Julian , Heinzman Jonathan T. , Sabbagh Sayeh , Cramer Ellyn M. , Duncan Gabrielle N. , Yuki Kumi , Close Liesl N. , Dlouhy Brian J. , Howard Matthew A. , Kawasaki Hiroto , Stein Kyle M. , Potash James B. , Shinozaki Gen
Published: March 2019

Aim

Glucocorticoids play a major role in regulating the stress response, and an imbalance of glucocorticoids has been implicated in stress‐related disorders. Within mouse models, CpGs across the genome have been shown to be differentially methylated in response to glucocorticoid treatment, and using the Infinium 27K array, it was shown that humans given synthetic glucocorticoids had DNA methylation (DNAm) changes in blood. However, further investigation of the extent to which glucocorticoids affect DNAm across a larger proportion of the genome is needed.

Methods

Buccal samples were collected before and after synthetic glucocorticoid treatment in the context of a dental procedure. This included 30 tooth extraction surgery patients who received 10 mg of dexamethasone. Genome‐wide DNAm was assessed with the Infinium HumanMethylationEPIC array.

Results

Five CpGs showed genome‐wide significant DNAm changes that were >10%. These differentially methylated CpGs were in or nearest the following genes: ZNF438, KLHDC10, miR‐544 or CRABP1, DPH5, and WDFY2. Using previously published datasets of human blood gene expression changes following dexamethasone exposure, a significant proportion of genes with false‐discovery‐rate‐adjusted significant CpGs were also differentially expressed. A pathway analysis of the genes with false‐discovery‐rate‐adjusted significant CpGs revealed significant enrichment of olfactory transduction, pentose and glucuronate interconversions, ascorbate and aldarate metabolism, and steroid hormone biosynthesis pathways.

Conclusion

High‐dose synthetic glucocorticoid administration in the setting of a dental procedure was significantly associated with DNAm changes within buccal samples. These findings are consistent with prior findings of an influence of glucocorticoids on DNAm in humans.
Photomorphogenesis of the root system in developing sunflower seedlings: a role for sucrose
Authors: Kutschera U. , Briggs W. R.
Published: March 2019

The domestic sunflower (Helianthus annuus L. cv. ‘Giganteus’) has been used since the 19th century as a model plant for the study of seedling development in darkness and white light (WL) (scoto‐ versus photomorphogenesis). However, most pertinent studies have focused on the developmental patterns of the hypocotyl and cotyledons, whereas the root system has been largely ignored.

In this study, we analysed entire sunflower seedlings (root and shoot) and quantified organ development in the above‐ and belowground parts of the organism under natural (non‐sterile) conditions.

We document that seedlings, raised in moist vermiculite, are covered with methylobacteria, microbes that are known to promote root development in Arabidopsis. Quantitative data revealed that during photomorphogenesis in WL, the root system expands by 90%, whereas stem elongation is inhibited, and hook opening/cotyledon expansion occurs. Root morphogenesis may be mediated via imported sucrose provided by the green, photosynthetically active cotyledons. This hypothesis is supported by the documented effect of sucrose on the induction of lateral root initials in sunflower cuttings. Under these experimental conditions, phytohormones (auxin, cytokinin, brassinolide) exerted little effect on root and cotyledon expansion, and no hormone‐induced initiation of lateral roots was observed.

It is concluded that sucrose not only acts as an energy source to fuel cell metabolism but is also a shoot‐derived signalling molecule that triggers root morphogenesis.
Efficacy of saliva substitutes and stimulants in the treatment of dry mouth
Authors: See Lydia , Mohammadi Mehdi , Han Phuu P. , Mulligan Roseann , Enciso Reyes
Published: February 2019

Aims

To evaluate the efficacy of saliva substitutes and stimulants compared to placebo in improving findings of dry mouth not caused by Sjӧgren's.

Methods and Results

Four databases were searched (PubMed, Web of Science, Cochrane Library, and EMBASE) through March 2018. Only randomized controlled trials (RCT) using placebo interventions with dry mouth patients were included. Outcomes included salivary flow and self‐reported patient improvement. The Cochrane Collaboration's tool for assessing risk of bias was used. A total of 348 references were reviewed, resulting in 7 RCTs with 257 dry mouth patients with 5 studies at high risk of bias, 1 unclear and 1 low risk being included. Topical spray of 1% malic acid increased unstimulated (Difference in Means [DM] = 0.096, 95% CI = 0.092‐0.100; P < 0.001) and stimulated (DM = 0.203, 95% CI = 0.106‐0.300; P < 0.001) salivary flow in 2 studies. Patients using 1% malic acid topical spray were 5.4 times more likely to report improvement compared to placebo (95% CI = 2.634‐11.091; P < 0.001) in 2 studies. No significant improvements were found with other products when compared to placebo.

Conclusion

Use of 1% malic acid topical spray seems to improve dry mouth compared to placebo. Quality of the evidence was low due to risk of bias and imprecision.
Palatal actinomycosis osteomyelitis–Complication of impacted tooth in a diabetic
Authors: Agarwal Padmanidhi , Chug Ashi , Kumar Shailesh , Jain Kanav
Published: March 2019

This article aims to highlight palatal actinomycosis osteomyelitis as an unseen complication of maxillary tooth impactions. A middle aged male with uncontrolled diabetes reported with a complaint of nasal regurgitation of fluids. After clinical and radiographic evaluation, he was diagnosed with actinomycosis osteomyelitis of the hard palate as a sequelae of a long‐standing palatally impacted tooth. He was treated by a combination of medical and surgical therapy. Palatal actinomycosis should be considered a differential in nonhealing lesions of the hard palate and a possibility before leaving maxillary impactions untreated, especially in immunocompromised individuals. Adequate follow‐up is mandatory to note for any radiographic changes and if diagnosed, treatment should be started promptly to prevent grave complications.
Genotyping and serotyping profiles showed weak Jka presentation for previously typed as Jknull donors
Authors: Wu Ping Chun , Chyan Tsui‐Wei , Feng Shu‐Hui , Chen Ming‐Hung , Pai Shun‐Chung
Published: March 2019

Background and Objectives

Kidd blood group system consists of two major antigens: Jka and Jkb. Both the antigens are absent in individuals typed as Jknull and may develop clinically significant anti‐Jk3 antibody. Screening donors for provision of Jknull blood is an ongoing task for blood centres with Jknull blood units kept frozen for specific requirements. In 2016, we discovered a previously typed Jknull donor to be Jka weak positive. Therefore, a study was conducted for our donors to verify Jknull status and to reinforce our typing protocol.

Materials and Methods

In this experiment, donors previously typed and screened as Jknull were tested with four antisera of Jka and Jkb, and each with gel card for serology testing. Sequence analysis was performed for SLC14A1 gene for the detection of JKnull and weak alleles for genetic testing.

Results

Among the 30 samples, four were serologically identified as Jk(a+w) and genotypically identified as heterozygous for the JK*01W.01 allele. The other 26 were confirmed to be Jknull with JK*02N.01 as the most frequent allele. None of JK*B weak alleles were detected, but three were identified as false positives in the tube method. Gel card gave great accuracy for Jkb detection, but failed to give consistent results for weak Jka.

Conclusion

By combining the tube method and gel card method in serology, along with complementary genetic testing, the possibility of misinterpreting weak Jka expression was eliminated, and we were able to provide Jknull blood for safe clinical transfusion.
Sexual dimorphism of liver endoplasmic reticulum stress susceptibility in prepubertal rats and the effect of sex steroid supplementation
Authors: Rossetti Camila Lüdke , de Oliveira Costa Hellen Marianne , Barthem Clarissa Souza , da Silva Michele Hinerasky , de Carvalho Denise P. , da‐Silva Wagner Seixas
Published: March 2019

New Findings

What is the central question of this study?

Is there sexual dimorphism in the occurrence of hepatic endoplasmic reticulum stress?

What is the main finding and its importance?

The transition from prepubertal to the adult age is associated with an increase in the unfolded protein response markers in the liver of male rats, which is probably due to an increase in serum testosterone levels.

Male rodents present a higher predisposition to obesity and insulin resistance than females. These disorders have been associated with endoplasmic reticulum (ER) stress. To investigate a possible sexual dimorphism in the hepatic occurrence of ER stress, we evaluated the expression of ER stress markers in the livers of male and female rats in two phases of sexual development. In the first experimental model, male and female prepubertal and adult Wistar rats were used. Adult males presented higher body mass and greater mass of the adipose tissue and liver than adult females. Prepubertal animals presented no differences in these parameters between males and females. Despite this finding, the hepatic expression levels of Bip, Ire1α and Xbp1s mRNA were lower in prepubertal males than in females, while in adult animals, they did not differ between sexes. In the second experimental model, we anticipated the sexually mature phase by daily injections of testosterone propionate for 10 days in prepubertal males or by daily injections of oestradiol benzoate for 7 days in prepubertal females. Oestradiol administration in prepubertal females did not change any of the parameters evaluated. Testosterone administration to prepubertal males led to a higher body mass and greater expression of Bip, Ire1α, Atf4 and Xbp1s in the liver. These findings suggest that the increased ER stress predisposition observed in males during puberty is due to an increase in testosterone levels, indicating that ER stress is sexually dimorphic before puberty due to the lack of testosterone in males.
Influencia del sexo, edad y cultura en las estrategias de afrontamiento de adolescentes paraguayos y mexicanos
Authors: Coppari Norma , Barcelata Eguiarte Blanca , Bagnoli Laura , Codas Zavala Gerónimo , López Humada Heidi , Martínez Cañete Úrsula
Published: February 2019

La adolescencia es un periodo sensible al estrés, sin embargo, el afrontamiento puede contribuir a una adaptación positiva, el cual tiende a cambiar en función de algunas variables personales como el sexo, la edad y contextuales, como la cultura. El objetivo de este trabajo fue analizar la influencia del sexo, edad y cultura en las estrategias de afrontamiento con adolescentes paraguayos y mexicanos. Se realizó un estudio de campo transversal, expos-facto, de tipo comparativo de dos muestras independientes con un diseño 2 x 2 x 2. Participaron de manera intencional 2278 adolescentes escolares paraguayos (n = 1188) y mexicanos (n = 1090), de 13 a 18 años (M = 15.15; DE = 1.48). Se aplicó la Escala de Afrontamiento para Adolescentes (ACS) que evalúa tres estilos y 18 estrategias de afrontamiento, y una cédula sociodemográfica. Se encontraron diferencias y efectos principales por edad y país en los estilos de afrontamiento productivo, no productivo y con referencia a otros y en algunas de sus estrategias. Las mujeres usan más estrategias de afrontamiento, muchas relacionadas con la búsqueda de apoyo social. Los adolescentes tempranos paraguayos y mexicanos tienden a presentar menos estrategias productivas. Solo se observaron efectos de interacción del sexo y la cultura en los estilos de afrontamiento. Estos datos aportan evidencia que podría ser útil para las políticas públicas de prevención y promoción de salud en adolescentes.
Green-State Micromilling of Additive Manufactured AISI316 L
Authors: Kuriakose Sandeep , Parenti Paolo , Cataldo Salvatore , Annoni Massimiliano
Published: March 2019

Additive manufacturing (AM) of metal offers matchless design sovereignty to manufacture metallic microcomponents from a wide range of materials. Green-state micromilling is a promising method that can be integrated into the AM of metallic feedstock microcomponents in typical extrusion-based AM methods for compensating the inability to generate microfeatures. The integration enables the manufacturing of complex geometries, the generation of good surface quality, and can provide exceptional flexibility to new product shapes. This work is a micromachinability study of AISI316 L feedstock components produced by extrusion-based AM where the effects of workpiece temperature and the typical micromilling parameters such as cutting speed, feed per tooth, axial depth of cut, and air supply are studied. Edge integrity and surface roughness of the machined slots, as well as cutting forces, are analyzed using three-dimensional microscopy and piezoelectric force sensor, respectively. Green-state micromilling results were satisfying with good produced quality. The micromilling of heated workpieces (45 °C), with external air supply for debris removal, showed the best surface quality with surface roughness values that reached around Sa = 1.5 μm, much smaller than the average metal particles size. Minimum tendency to borders breakage was showed but in some cases microcutting was responsible of the generation of surface defects imputable to lack of adhesion of deposited layers. Despite this fact, the integrability of micromilling into extrusion-based AM cycles of metallic feedstock is confirmed.
Reliability Considerations for Oil Immersion-Cooled Data Centers
Authors: Shah Jimil M. , Eiland Richard , Rajmane Pavan , Siddarth Ashwin , Agonafer Dereje , Mulay Veerendra
Published: March 2019

The improved efficiency of mineral oil may offer simplicity in facility design compared to traditional air cooling and provide a means for cost savings. Despite its improved cooling efficiency and cost savings, a mineral oil immersion cooling technique is still not widely implemented and original equipment manufacturers are reluctant to jeopardize sales of existing air-based cooling system equipment. Only compelling physics regarding thermal performance of direct immersion cooling is not enough for data center operators. Many uncertainties and concerns persist regarding the effects of mineral oil immersion cooling on the reliability of information technology (IT) equipment both at the component and chassis level. This paper is a first attempt at addressing this challenge by reviewing the changes in physical and chemical properties of IT equipment materials like polyvinyl chloride (PVC), printed circuit board (PCB), and capacitors and characterizes the interconnect reliability of materials. The changes in properties of a mineral oil like kinematic viscosity and dielectric strength are also cited as important factors and discussed briefly. The changes in mechanical properties like elasticity, hardness, swelling, and creep are being shown in the paper for thermoplastic materials. The chemical reaction between material and mineral oil as a function of time and temperature is also conferred. The literature gathered on the subject and quantifiable data gathered by the authors provide the primary basis for this research document.
Cylindrical Tuber Encapsulant Layer Realization by Patterned Surface for Chip-on-Board Light-Emitting Diodes Packaging
Authors: Yu Xingjian , Hu Run , Wu Ruikang , Xie Bin , Zhang Xiaoyu , Luo Xiaobing
Published: March 2019

In this study, we realized a cylindrical tuber silicone layer for improving the light efficiency of chip-on-board light-emitting diodes (COB-LEDs) by fabricating patterned LED substrate with both silicone-wetting and silicone-repellency surfaces. To realize silicone-repellency surface, low surface energy modified nanosilica particles were prepared and deposited on the LED substrate to form porous hierarchical structure. Light efficiency enhancement for blue light COB-LEDs with pure cylindrical tuber silicone layer and white light COB-LEDs with phosphor–silicone composite layer was studied. The results show that for blue light COB-LEDs with pure cylindrical tuber silicone layer, the light efficiency increases with the contact angle and a highest light efficiency enhancement of 62.6% was achieved at 90 deg when compared to the flat silicone layer. For white light COB-LEDs at correlated color temperature (CCT) of ∼5500 K, the cylindrical tuber silicone layer enhances the light efficiency by 13.6% when compared to the conventional flat phosphor layer.
Heat Pipe Thermal Management at Hypersonic Vehicle Leading Edges: A Low-Temperature Model Study
Authors: Kasen Scott D. , Wadley Haydn N. G.
Published: March 2019

The intense thermal fluxes and aero-thermomechanical loads generated at sharp leading edges of atmospheric hypersonic vehicles traveling above Mach 5 have motivated an interest in novel thermal management strategies. Here, we use a low-temperature stainless steel-water system to experimentally investigate the feasibility of metallic leading edge heat pipe concepts for thermal management in an efficient load supporting structure. The concept is based upon a two-phase, high thermal conductance “heat pipe” which redistributes the localized thermal flux created at the leading edge stagnation point over a larger surface for effective removal. Structural efficiency is achieved by configuring the system as a wedge-shaped sandwich panel with an I-cell core that simultaneously permits axial vapor and returns liquid flow. The measured axial temperature profiles resulting from a localized thermal flux applied to the tip are consistent with effective thermal spreading that lowered the peak leading edge temperature and reduced the temperature gradients when compared with an equivalent structure containing no working fluid. A simple finite element model that treated the vapor as an equivalent, high thermal conductivity material was in good agreement with these experiments. The model is then used to design a niobium alloy-lithium system that is shown to be suitable for enthalpy conditions representative of Mach 7 scramjet-powered flight. The study indicates that the surface temperature reductions of heat pipe-based leading edges may be sufficient to permit the use of nonablative, refractory metal leading edges with oxidation protection in hypersonic environments.
Efficient Design Method for Applying Vortex Generators in Turbomachinery
Authors: Li Jiabin , Ji Lucheng
Published: March 2019

Secondary flow limits the aerodynamic loading level of turbomachinery. Vortex generators (VGs) offer the potential to attenuate secondary flow when implemented at the endwall of the blade passage. Customary design usually relies on computational fluid dynamics (CFD); however, VG geometry modeling and mesh generation are challenging. This paper presents an efficient method for designing the optimal VG layout. In this approach, first, a mathematical model (BAYC) is introduced to replace the actual VGs; hence, simulation can be carried out without detailed VG gridding. Second, an optimization procedure with response surface methods is employed to determine the optimal VG layout. To illustrate the proposed method, compressor cascades with one and three VGs are used as the test cases. The results demonstrate that the optimal VG layout may effectively weaken the secondary flow and can decrease the aerodynamic loss by 15–25% in almost all incidence angle ranges, particularly at positive incidence angles. Flow mechanism analysis indicates that VGs can enhance the boundary layer kinetic energy, thereby elevating the capability to withstand adverse pressure gradients.
Three-Dimensional Unit Cell Study of a Porous Bulk Metallic Glass Under Various Stress States
Authors: Gouripriya S , Tandaiya Parag
Published: March 2019

Porous bulk metallic glasses (BMGs) exhibit an excellent combination of superior mechanical properties such as high strength, high resilience, large malleability, and energy absorption capacity. However, a mechanistic understanding of their response under diverse states of stress encountered in practical load-bearing applications is lacking in the literature. In this work, this gap is addressed by performing three-dimensional finite element simulations of porous BMGs subjected to a wide range of tensile and compressive states of stress. A unit cell approach is adopted to investigate the mechanical behavior of a porous BMG having 3% porosity. A parametric study of the effect of stress triaxialities T = 0, ±1/3, ±1, ±2, ±3, and ±∞, which correspond to stress states ranging from pure deviatoric stress to pure hydrostatic stress under tension and compression, is conducted. Apart from the influence of T, the effects of friction parameter, strain-softening parameter and Poisson’s ratio on the mechanics of deformation of porous BMGs are also elucidated. The results are discussed in terms of the simulated stress-strain curves, pore volume fraction evolution, strain to failure, and development of plastic deformation near the pore. The present results have important implications for the design of porous BMG structures.
Discrete Time-Delay Optimal Control Method for Experimental Active Chatter Suppression and Its Closed-Loop Stability Analysis
Authors: Zhang Xingwu , Yin Ziyu , Gao Jiawei , Liu Jinxin , Gao Robert X. , Cao Hongrui , Chen Xuefeng
Published: March 2019

Chatter is a self-excited and unstable vibration phenomenon during machining operations, which affects the workpiece surface quality and the production efficiency. Active chatter control has been intensively studied to mitigate chatter and expand the boundary of machining stability. This paper presents a discrete time-delay optimal control method for chatter suppression. A dynamical model incorporating the time-periodic and time-delayed characteristic of active chatter suppression during the milling process is first formulated. Next, the milling system is represented as a discrete linear time-invariant (LTI) system with state-space description through averaging and discretization. An optimal control strategy is then formulated to stabilize unstable cutting states, where the balanced realization method is applied to determine the weighting matrix without trial and error. Finally, a closed-loop stability lobe diagram (CLSLD) is proposed to evaluate the performance of the designed controller based on the proposed method. The CLSLD can provide the stability lobe diagram with control and evaluate the performance and robustness of the controller cross the tested spindle speeds. Through many numerical simulations and experimental studies, it demonstrates that the proposed control method can make the unstable cutting parameters stable with control on, reduce the control force to 21% of traditional weighting matrix selection method by trial and error in simulation, and reduce the amplitude of chatter frequency up to 78.6% in experiment. Hence, the designed controller reduces the performance requirements of actuators during active chatter suppression.
Environmental Effect on the Crack Behavior of Yttria-Stabilized Zirconia During Laser Drilling
Authors: Shen Hong , Jiang Juan , Feng Decai , Xing Chen , Zhao Xiaofeng , Xiao Ping
Published: March 2019

The crack behaviors of yttrium-stabilized zirconia during laser drilling in air, vacuum, and water environments were investigated. Due to the high stress and low fracture toughness induced by tetragonal-monoclinic phase transformation, tremendous cracks occur during drilling in air. Contrastly, cracks were reduced in vacuum drilling since the phase transformation was suppressed due to the generation of oxygen vacancies. By protection of water, no cracks were observed due to low stress and maintained fracture toughness. The crack mechanisms in different drilling media were discussed.
A Fabric-Based Wearable Soft Robotic Limb
Authors: Liang Xinquan , Cheong Haris , Chui Chee Kong , Yeow Chen-Hua
Published: March 2019

In this paper, a fabric-based wearable soft robotic limb (SRL) is presented. It can be worn on the user’s body to potentially assist with activities of daily living. This SRL can perform a bidirectional bending motion by inflating the pneumatic bending actuators. The end effector, which is a fabric-based soft gripper, can pick up small objects in daily life. The SRL is pneumatically actuated, and its bending motion and payload capability were characterized. All the actuation and control systems are integrated in a portable control box. The SRL can be voice-controlled using an Android-based voice recognition mobile application. We expect the SRL to be a promising wearable tool that can assist the user in managing simple activities in daily living, while allowing the user’s natural human hands to work on more complex tasks.
Effects of flow recirculation on unmanned aircraft system (UAS) acoustic measurements in closed anechoic chambers
Authors: Stephenson James H. , Weitsman Daniel , Zawodny Nikolas S.
Published: March 2019

An experimental campaign was undertaken to identify the effects of flow recirculation on an isolated rotor's acoustic emissions in a closed anechoic chamber. It is shown that flow recirculation results in a significant increase in higher harmonic noise, with an increase of more than 15 dB in some harmonics. This increase in noise is due to the nature of testing in a closed facility and does not represent the acoustic emissions of a similar rotor in hovering flight outdoors. Future measurements of rotors and full unmanned aerial vehicles in closed anechoic chambers must acknowledge recirculation effects and attempt to mitigate the effect on reported measurements.
Element-Specific Magnetic Microscopy with Circularly Polarized X-rays
Authors: Stöhr J. , Wu Y. , Hermsmeier B. D. , Samant M. G. , Harp G. R. , Koranda S. , Dunham D. , Tonner B. P.
Published: March 2019

Circularly polarized soft x-rays have been used with an imaging photoelectron microscope to record images of magnetic domains at a spatial resolution of 1 micrometer. The magnetic contrast, which can be remarkably large, arises from the fact that the x-ray absorption cross section at inner-shell absorption edges of aligned magnetic atoms depends on the relative orientation of the photon spin and the local magnetization direction. The technique is element-specific, and, because of the long mean free paths of the x-rays and secondary electrons, it can record images of buried magnetic layers.
Revised paleoaltimetry data show low Tibetan Plateau elevation during the Eocene
Authors: Botsyun Svetlana , Sepulchre Pierre , Donnadieu Yannick , Risi Camille , Licht Alexis , Caves Rugenstein Jeremy K.
Published: March 2019

Ancient height of the Tibetan Plateau

The elevation of the Tibetan Plateau has a major impact on climate, affecting the monsoons and regional weather patterns. Although some isotope proxies have suggested a roughly equivalent height for the plateau as far back as the Eocene (∼40 million years ago), other lines of evidence suggest a lower elevation in the distant past. Botsyun
et al.
used a model to show that several previously overlooked factors contribute to the isotopic record from the Eocene (see the Perspective by van Hinsbergen and Boschman). The results harmonize the isotopic record with other proxies and argue for a Tibetan Plateau that was about 1000 meters lower than it is today.

Science
, this issue p.
eaaq1436
; see also p.
928
Glutamate signaling at cytoneme synapses
Authors: Huang Hai , Liu Songmei , Kornberg Thomas B.
Published: March 2019

Cytoneme signaling in fly development

During development of certain tissues in the fruit fly, signaling from one tissue to another appears to occur through specialized filopodia called cytonemes. The cytonemes contain receptors and reach close toward the signal-producing cells. Huang
et al.
report that components of neuronal signaling at synapses also function in proper formation of cytoneme appositions and signaling. Various manipulations of calcium signaling, expression of dominant-negative glutamate receptor proteins, or depletion of vesicle transport proteins or components of voltage-gated calcium channels influenced the presence of cytonemes and signaling.

Science
, this issue p.
948
Coupled ripple oscillations between the medial temporal lobe and neocortex retrieve human memory
Authors: Vaz Alex P. , Inati Sara K. , Brunel Nicolas , Zaghloul Kareem A.
Published: March 2019

Coupled ripples in memory

Short-lived, high-frequency oscillations in the brain called ripples have been implicated as substrates for memory formation. There is, however, little evidence linking ripple activity with awake memory retrieval in humans. Vaz
et al.
analyzed intracranial recordings in human subjects (see the Perspective by Gelinas). They found that ripple oscillations in the brain's medial temporal lobe were coupled with ripple oscillations in the temporal cortex. This coupling was enhanced just before successful memory retrieval. During successful retrievals with ripples, patterns of oscillations were recapitulated across multiple electrodes, consistent with the initial encoding. The observation that ripple oscillations occur before successful memory retrieval suggests that they may play a mechanistic role in the retrieval process.

Science
, this issue p.
975
; see also p.
927
Motor cortical control of vocal interaction in neotropical singing mice
Authors: Okobi Daniel E. , Banerjee Arkarup , Matheson Andrew M. M. , Phelps Steven M. , Long Michael A.
Published: March 2019

Turn-taking in singing mice

The ability to take turns is a hallmark of social interaction among animals. It occurs in many different species, from dueting birds to frogs, and is a notable part of human speech. Such rapid response requires a complex cascade of sensory and motor actions that has been difficult to characterize. Okobi
et al.
examined turn-taking in tropical singing mice, in which males interrupt, and alter, each other's songs (see the Perspective by Hage). They describe an orofacial motor cortex that mediates rapid transition from the motor cortex to the vocal motor apparatus and facilitates rapid vocal interactions.

Science
, this issue p.
983
see also p.
926
Pantropical climate interactions
Authors: Cai Wenju , Wu Lixin , Lengaigne Matthieu , Li Tim , McGregor Shayne , Kug Jong-Seong , Yu Jin-Yi , Stuecker Malte F. , Santoso Agus , Li Xichen , Ham Yoo-Geun , Chikamoto Yoshimitsu , Ng Benjamin , McPhaden Michael J. , Du Yan , Dommenget Dietmar , Jia Fan , Kajtar Jules B. , Keenlyside Noel , Lin Xiaopei , Luo Jing-Jia , Martín-Rey Marta , Ruprich-Robert Yohan , Wang Guojian , Xie Shang-Ping , Yang Yun , Kang Sarah M. , Choi Jun-Young , Gan Bolan , Kim Geon-Il , Kim Chang-Eun , Kim Sunyoung , Kim Jeong-Hwan , Chang Ping
Published: March 2019

Tropical interconnections

The El Niño–Southern Oscillation, which originates in the tropical Pacific, affects the rest of the world's tropics by perturbing global atmospheric circulation. Less appreciated than this influence is how the tropical Atlantic and Indian Oceans affect the Pacific. Cai
et al.
review what we know about these pantropical interactions, discuss possible ways of improving predictions of current climate variability, and consider how projecting future climate under different anthropogenic forcing scenarios may be improved. They argue that making progress in this field will require sustained global climate observations, climate model improvements, and theoretical advances.

Science
, this issue p.
eaav4236
Interface and heterostructure design in polyelemental nanoparticles
Authors: Chen Peng-Cheng , Liu Mohan , Du Jingshan S. , Meckes Brian , Wang Shunzhi , Lin Haixin , Dravid Vinayak P. , Wolverton Chris , Mirkin Chad A.
Published: March 2019

Phases of multielement nanoparticles

Thermodynamically stable metal nanoparticles composed of multiple elements could, in principle, exhibit several different phases that form multiple interfaces. Chen
et al.
explored the structure and composition of palladium-tin alloy nanoparticles formed with up to five other elements after high-temperature annealing. Triphase nanoparticles possessed two or three interface architectures, and tetraphase nanoparticles exhibited up to six interfaces. Theoretical and experimental studies revealed how the balance between surface and interfacial energies influences the observed phases and interface structure.

Science
, this issue p.
959