bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of acid concentration and the UHP pretreatment on the gelatinisation of collagen and the properties of extracted gelatins
Authors: Zhang Yuhao , Ma Liang , Cai Luyun , Zhou Mengrou , Li Jianrong
Published: March 2016

An ultra‐high‐pressure (UHP) transmission medium with HCl was applied as a pretreatment to extract gelatin. The effects of the acid concentration (0–1% (w/v)) on the gelatinisation of collagen and the properties of gelatin were investigated. An increase in the acid concentration decreased the thermostability of collagen and increased the yield of gelatin (from 64% increased to 80%). The content of the subunit components in the pretreated collagen and the gelatin declined slightly as the acid concentration was increased, resulted in slight decrease (P > 0.05) in the gel strength (from 435 g decreased to 408 g). The analysis of Fourier transform infrared spectroscopy (FTIR) spectra showed that the triple‐helical structure, secondary structures of the collagen and covalent cross‐linking in the collagenous fibres were damaged gradually as the acid concentration was increased. The scanning electron microscopy (SEM) images showed that the smooth surface of collagen was partly disrupted with microvoids after UHP/1% HCl pretreatment, which may be related to the damage on the covalent cross‐linking.
Quality identification and evaluation of Pu‐erh teas of different grade levels and various ages through sensory evaluation and instrumental analysis
Authors: Gao Lin , Bian Mengxian , Mi Ruifang , Hu Xiaosong , Wu Jihong
Published: March 2016

To develop an objective, effective, flexible and cost‐saving method to assess Pu‐erh tea quality, Pu‐erh tea samples of different grade levels and various ages were analysed using sensory evaluation and various instrumental techniques, including chemical analysis and electronic tongue (ET). Results showed that taste profile analysis as a sensory evaluation method can meticulously describe and distinguish different Pu‐erh tea samples. Chemical analysis combined with hierarchical cluster analysis can cluster Pu‐erh ripened and raw tea both in compressed and scattered forms. However, no obvious variation tendency was observed in the chemical composition parameters of Pu‐erh tea of different grade levels or various ages. ET combined with principal components analysis (PCA) is effective in classifying Pu‐erh tea samples of different grade levels and various ages. ET followed by linear discriminant analysis (LDA) performs well in identifying Pu‐erh tea samples of various ages by establishing a discriminant model.
Preoperative Diagnosis of Juxtaglomerular Cell Tumors in Eight Patients
Authors: Kang Suhai , Chen Fang , Zhong Yan , Han Baiyu , Cheng Guanghe , Guo Aitao , Tian Yuan , Tong Xinyuan , Dou Jingtao , Ye Huiyi
Published: March 2016

The aim of this study was to improve the diagnostic efficiency for juxtaglomerular cell tumors (JCTs) and to determine whether clinical and magnetic resonance imaging features can help to differentiate JCTs from clear cell renal cell carcinoma (ccRCC). The clinical features of eight patients with JCTs and 27 patients with ccRCCs were analyzed. A flow diagram for young people with hypertension was applied to facilitate the diagnosis. Clinical presentations were analyzed, including age, hypertension, and hypokalemia. The results of our study produced a flow diagram that narrowed the scope of diagnosis. The statistical results demonstrated that patients with a renal mass aged 14 to 30 years, had grade 3 hypertension, or had moderate hypokalemia had a greater possibility of having a JCT than a ccRCC (P<.0000, P<.01, P<.0005, respectively). In addition, the flow diagram and magnetic resonance imaging features were useful to distinguish JCTs from other renal tumors.
Effective treatment with combination of peripheral 5‐hydroxytryptamine synthetic inhibitor and 5‐hydroxytryptamine 2 receptor antagonist on glucocorticoid‐induced whole‐body insulin resistance with hyperglycemia
Authors: Ma Shaoxin , Li Tao , Guo Keke , Li Xin , An Shanshan , Hou Shanshan , Chen Ru , Yang Bo , Liu Siyu , Fu Jihua
Published: March 2016

Aims/Introduction

Our previous study found that dexamethasone‐induced insulin resistance (IR) was involved in 5‐hydroxytryptamine (5‐HT) synthesis and 5‐hydroxytryptamine 2 receptor (5‐HT2R) in the periphery. The present study examined the effects of inhibitions of both peripheral 5‐HT synthesis and 5‐HT2R on dexamethasone‐induced IR.

Materials and Methods

Male rats were exposed to dexamethasone for 10 days, then treated with or without a 5‐HT2R antagonist, sarpogrelate, a 5‐HT synthetic inhibitor, carbidopa, alone or in combination for 20 days.

Results

Dexamethasone‐induced whole‐body IR, with glucose intolerance, decreased insulin sensitivity, hyperglycemia, hyperinsulinemia and dyslipidemia, could be effectively abolished by sarpogrelate or/and carbidopa, whereas IR‐related actions of dexamethasone in tissues were accompanied by increased 5‐HT synthesis in the liver and visceral adipose, and upregulated 5‐HT2R (5‐HT2AR and 5‐HT2BR) expression in these two tissues as well as in skeletal muscle. Sarpogrelate or/and carbidopa treatment significantly abolished dexamethasone‐caused tissue‐specific IR. In the liver, increased gluconeogenesis, triglycerides and very low‐density lipoprotein syntheses with steatosis, and downregulated expression of plasmalemmal glucose transporter‐2 were markedly reversed. In the visceral adipose and skeletal muscle, downregulated expression of plasmalemmal glucose transporter‐4 was significantly reversed, and increased lipolysis was also reversed in the visceral adipose. Dexamethasone‐induced activations of hepatic mammalian target of rapamycin serine2448, and S6K threonine389/412 phosphorylation were also abolished markedly by sarpogrelate or/and carbidopa. Co‐treatment with sarpogrelate and carbidopa showed a synergistic effect on suppressing dexamethasone actions.

Conclusion

Inhibitions of both peripheral 5‐HT synthesis and 5‐HT2R are expected to be a dependable target for treatment of steroid‐induced diabetes.
Investigating social functioning after early mild TBI: the quality of parent–child interactions
Authors: Lalonde Gabrielle , Bernier Annie , Beaudoin Cindy , Gravel Jocelyn , Beauchamp Miriam H.
Published: March 2016

The young brain is particularly vulnerable to injury due to inherent physiological and developmental factors, and even mild forms of traumatic brain injury (mTBI) can sometimes result in cognitive and behavioural difficulties. Despite the high prevalence of paediatric mTBI, little is known of its impact on children's social functioning. Parent–child relationships represent the centre of young children's social environments and are therefore ideal contexts for studying the potential effects of mTBI on children's social functioning. The aim of this study was to assess the quality of parent–child interactions after mTBI using observational assessment methods and parental report. The sample included 130 children (18–60 months at recruitment) divided into three groups: children with uncomplicated mTBI (n = 47), children with orthopaedic injury (OI, n = 27), and non‐injured children (NI, n = 56). The quality of parent–child interactions was assessed 6 months post‐injury using the Mutually Responsive Orientation (MRO) scale, an observational measure which focuses on the dyadic nature of parent–child exchanges, and the Parental Stress Index questionnaire (Parent‐Child Dysfunctional Interaction (PCDI) domain). Significant differences with medium effect sizes were found between the mTBI group and the NI group on the MRO, but not between the OI group and the other two groups. PCDI scores did not differ across groups, suggesting that observational measures may be more sensitive to changes in parent–child interactions after TBI. The current findings have implications for children's post‐injury social development and highlight the importance of monitoring social outcomes even after minor head injuries.
When Empathy Matters: The Role of Sex and Empathy in Close Friendships
Authors: Ciarrochi Joseph , Parker Philip D. , Sahdra Baljinder K. , Kashdan Todd B. , Kiuru Noona , Conigrave James
Published: March 2016

Based on prior theory and research (Ciarrochi & Heaven, 2009; Eagly & Wood, 1999), we hypothesized that the link between empathy and friendship would be moderated by sex: Girls will nominate empathic boys as friends, whereas boys will not tend to nominate empathic girls. We collected measures of empathy, friendship social support, and close friendship nominations in grade 10 across 1,970 students in 16 schools (Mage = 15.70, SD = .44; males = 993, females = 977). Multilevel models revealed that boys high in cognitive empathy attracted an average of 1.8 more girl friendship nominations than did their low empathy counterparts, whereas empathic girls did not attract a greater number of opposite‐sex friends. In addition, the more friendship nominations a boy received from either boys or girls, the more they felt supported by their friends; the number of friendship nominations received by girls, in contrast, had no effect on their felt support by friends. Regardless of the quantity of friendship nominations, empathy was linked to more supportive friendships for both males and females. These results inform a contextual understanding of the role of empathy in selecting and maintaining friendships.
Genetic isolation between coastal and fishery‐impacted, offshore bottlenose dolphin (Tursiops spp.) populations
Authors: Allen Simon J. , Bryant Kate A. , Kraus Robert H. S. , Loneragan Neil R. , Kopps Anna M. , Brown Alexander M. , Gerber Livia , Krützen Michael
Published: March 2016

The identification of species and population boundaries is important in both evolutionary and conservation biology. In recent years, new population genetic and computational methods for estimating population parameters and testing hypotheses in a quantitative manner have emerged. Using a Bayesian framework and a quantitative model‐testing approach, we evaluated the species status and genetic connectedness of bottlenose dolphin (Tursiops spp.) populations off remote northwestern Australia, with a focus on pelagic ‘offshore’ dolphins subject to incidental capture in a trawl fishery. We analysed 71 dolphin samples from three sites beyond the 50 m depth contour (the inshore boundary of the fishery) and up to 170 km offshore, including incidentally caught and free‐ranging individuals associating with trawl vessels, and 273 dolphins sampled at 12 coastal sites inshore of the 50 m depth contour and within 10 km of the coast. Results from 19 nuclear microsatellite markers showed significant population structure between dolphins from within the fishery and coastal sites, but also among dolphins from coastal sites, identifying three coastal populations. Moreover, we found no current or historic gene flow into the offshore population in the region of the fishery, indicating a complete lack of recruitment from coastal sites. Mitochondrial DNA corroborated our findings of genetic isolation between dolphins from the offshore population and coastal sites. Most offshore individuals formed a monophyletic clade with common bottlenose dolphins (T. truncatus), while all 273 individuals sampled coastally formed a well‐supported clade of Indo‐Pacific bottlenose dolphins (T. aduncus). By including a quantitative modelling approach, our study explicitly took evolutionary processes into account for informing the conservation and management of protected species. As such, it may serve as a template for other, similarly inaccessible study populations.
Redrawing the map: mtDNA provides new insight into the distribution and diversity of short‐finned pilot whales in the Pacific Ocean
Authors: Van Cise Amy M. , Morin Phillip A. , Baird Robin W. , Lang Aimee R. , Robertson Kelly M. , Chivers Susan J. , Brownell Robert L. , Martien Karen K.
Published: March 2016

Correlations between morphological and genetic data provide evidence to delineate species or evolutionarily significant units, which then become the units to conserve in management plans. Here, we examine the distribution and genetic differentiation of two morphotypes of short‐finned pilot whale (Globicephala macrorhynchus) in the Pacific Ocean. Mitochondrial control region sequences from 333 samples were combined with 152 previously published sequences to describe genetic variability globally and population structure in the Pacific. Although genetic variability is low, we found strong differentiation at both broad and local levels across the Pacific. Based on genetics, two types are distributed throughout the Pacific, one predominantly in the eastern Pacific and the other in the western and central Pacific. In the eastern Pacific Ocean, no correlation was found between distribution and sea surface temperature. The two types have broad latitudinal ranges, suggesting their distributions are likely driven by more complex factors, such as prey distribution, rather than sea surface temperature.
Niche heterogeneity in the bone marrow
Authors: Birbrair Alexander , Frenette Paul S.
Published: March 2016

In adult mammals, hematopoietic stem cells (HSCs) are defined by their abilities to self‐renew and to differentiate to form all blood cell lineages. These rare multipotent cells occupy specific locations in the bone marrow (BM) microenvironment. The specific microenvironment regulating HSCs, commonly referred to as the niche, comprises multiple cell types whose exact contributions are under active investigation. Understanding cellular cross talk involving HSCs in the BM microenvironment is of fundamental importance for harnessing therapies against benign and malignant blood diseases. In this review, we summarize and evaluate recent advances in our understanding of niche heterogeneity and its influence on HSC function.
Endothelial‐to‐hematopoietic transition: Notch‐ing vessels into blood
Authors: Kanz Dirk , Konantz Martina , Alghisi Elisa , North Trista E. , Lengerke Claudia
Published: March 2016

During development, hematopoietic stem cells (HSCs) are formed in a temporally and spatially restricted manner, arising from specialized endothelial cells (ECs) in the ventral wall of the dorsal aorta within the evolutionary conserved aorta–gonad–mesonephros region. Our understanding of the processes regulating the birth of HSCs from ECs has been recently advanced by comprehensive molecular analyses of developing murine hematopoietic cell populations complemented by studies in the zebrafish model, with the latter offering unique advantages for genetic studies and direct in vivo visualization of HSC emergence. Here, we provide a concise review of the current knowledge and recent advances regarding the cellular origin and molecular regulation of HSC development, with particular focus on the process of endothelial‐to‐hematopoietic transition and its primary regulator, the Notch signaling pathway.
A randomized comparison of pediatric‐sized Streamlined Liner of Pharyngeal Airway™ and Laryngeal Mask Airway‐Unique™ in paralyzed children
Authors: Zhu Wenxiu , Wei Xinchuan
Published: March 2016

Background

The pediatric‐sized Streamlined Liner of Pharyngeal Airway™ (SLIPA) is a new supraglottic airway device for children.

Aims

The aim of this study was to compare the clinical performance of the pediatric‐sized SLIPA with the Laryngeal Mask Airway‐Unique in paralyzed children under positive pressure‐controlled ventilation (PCV).

Methods

One hundred children, aged 2 months to 12 years with American Society of Anesthesiologists physical status I–II were enrolled and randomly allocated to the SLIPA group or the Laryngeal Mask Airway‐Unique group (50 patients in each group). The primary outcome variable was oropharyngeal leak pressure. Other outcome variables were first insertion success rate, insertion time, minor airway interventions required for successful insertion, intraoperative dislodgement, ventilatory data, and perioperative complications.

Results

The insertion characteristics, ventilation data, and perioperative complications were comparable between the two groups. The leak pressure of the SLIPA was significantly higher than that of the Laryngeal Mask Airway‐Unique [median (IQR): 25 (22–30) cmH2O vs 21 (19–26) cmH2O, respectively; mean ± sd: 25.3 ± 4.6 cmH2O vs 22.6 ± 4.8 cmH2O, respectively; P = 0.006]. The incidence of intraoperative dislodgment was significantly lower in the SLIPA group than in the Laryngeal Mask Airway‐Unique group (0 vs 6 patients, respectively; P = 0.027).

Conclusions

In conclusion, both the SLIPA and the Laryngeal Mask Airway‐Unique can be used effectively without severe complications in paralyzed children. Additionally, the SLIPA provides a better airway seal and better intraoperative position stability than the Laryngeal Mask Airway‐Unique.
Compatibility of common drugs with acetate‐containing balanced electrolyte solutions in pediatric anesthesia
Authors: Heiderich Sebastian , Jürgens Jonas , Rudolf Daniel , Dennhardt Nils , Echtermeyer Frank , Leffler Andreas , Sümpelmann Robert , Lichtinghagen Ralf , Witt Lars
Published: March 2016

Background

Acetate‐containing balanced electrolyte solutions are frequently used for fluid therapy in pediatric anesthesia, but no studies investigating the compatibility with common anesthetic drugs are available.

Aim

To reveal possible incompatibilities between common anesthetic drugs and the acetate‐containing balanced electrolyte solutions BS (Sterofundin ISO; B.Braun Melsungen AG, Melsungen, Germany) and BS‐G1 (E148G1 Päd; Serumwerk Bernburg AG, Bernburg, Germany), with normal saline (NS) as control.

Methods

All tested infusion solutions were mixed 1 : 1 with 28 common anesthetic drugs in concentrations used in daily clinical practice. Electrical conductivity, pH, and turbidimetric light diffusion at 405 nm were measured. Macroscopic changes such as gross precipitation, change in color, or bubble formation were also assessed. All measurements were performed immediately after mixing as well as 30 and 60 min after.

Results

The vast majority of drugs showed no significant change in pH, electric conductivity, turbidimetric detectable light diffusion, or macroscopic appearance after mixing with BS, BS‐G1, and NS. Phenytoin immediately precipitated in response to all tested solutions as did diazepam. Thiopental precipitated after mixing with BS only.

Conclusions

Most of the tested drugs did not show any signs or evidence of incompatibility reactions. However, phenytoin and diazepam should not be in contact with the three tested solutions, including NS. Thiopental should be used with caution because it can precipitate in solutions with a low pH (e.g., BS).
Chemotherapy‐induced B‐cell depletion in hepatoblastoma patients undergoing ABO‐incompatible living donor liver transplantation
Authors: Kanazawa Hiroyuki , Fukuda Akinari , Mali Vidyadhar Padmakar , Rahayatri Tri Hening , Hirata Yoshihiro , Sasaki Kengo , Uchida Hajime , Shigeta Takanobu , Sakamoto Seisuke , Matsumoto Kimikazu , Kasahara Mureo
Published: March 2016

LT from ABO‐I donors requires preconditioning regimens to prevent postoperative catastrophic AMR. NAC for HBL is known to cause myelosuppression leading to a reduction in the number and function of lymphocytes. We investigated this chemotherapy‐induced myelosuppression in HBL patients listed for LT from ABO‐I donors with reference to the kinetics of B, T cells, and anti‐ABO blood type isoagglutinin titers. Between 2005 and 2015, of the 319 patients who underwent LDLT at our institute, 12 were indicated for unresectable HBL. Three patients with unresectable HBL who underwent LDLT from ABO‐I donors are included in this study. Immunosuppression consisted of a standard regime of tacrolimus and low‐dose steroids as in ABO compatible/identical LDLT. No additional preoperative therapies for B‐cell depletion were used. Absolute lymphocyte counts, lymphocyte subsets (including CD20+ B cells, CD3+CD4+ T cells and CD3+CD8+ T cells), and anti‐ABO blood type isoagglutinin titers were measured before LDLT and postoperatively. The median age at diagnosis was 19 months (range, 3–31 months). The median follow‐up was seven months (range, 6–15 months). The median interval from the last NAC to LDLT was 33 days (range, 25–52 days). The median interval from LDLT to adjuvant chemotherapy was 28 days (range, 22–36 days). The counts of CD20+ B cells before LDLT were depleted to median 5 cells/mm3 (range, 0–6 cells/mm3). There was a transient rebound in the CD20+ B cell counts on day seven (maximum of 82 cells/mm3) followed by a decline starting at 14 days after LDLT that was sustained for the duration of adjuvant chemotherapy. Anti‐ABO blood type isoagglutinin titers were lowered to between 1:1 and 1:16 before LDLT and remained low for the duration of follow‐up in this study. All of the three patients remained in good health without either acute cellular or AMR after LDLT. The B‐cell depletion that occurs after cisplatin‐based chemotherapy for HBL may help accomplish safe ABO‐I LDLT in children without the use of additional conditioning regimens for prevention of AMR.
Differential T‐cell responses to a chimeric Plasmodium falciparum antigen; UB05‐09, correlates with acquired immunity to malaria
Authors: Dinga J. N. , Njimoh D. L. , Kiawa B. , Djikeng A. , Nyasa R. B. , Nkuo‐Akenji T. , Pellé R. , Titanji V. P. K.
Published: March 2016

The development of a sterilizing and cost‐effective vaccine against malaria remains a major problem despite recent advances. In this study, it is demonstrated that two antigens of P. falciparum UB05, UB09 and their chimera UB05‐09 can serve as protective immunity markers by eliciting higher T‐cell responses in malaria semi‐immune subjects (SIS) than in frequently sick subjects (FSS) and could be used to distinguish these two groups. UB05, UB09 and UB05‐09 were cloned, expressed in E. coli, purified and used to stimulate PBMCs isolated from 63 subjects in a malaria endemic area, for IFN‐γ production, which was measured by the ELISpot assay. The polymorphism of UB09 gene in the malaria infected population was also studied by PCR/sequencing of the gene in P. falciparum field isolates. All three antigens were preferentially recognized by PBMCs from SIS. IFN‐γ production induced by these antigens correlated with the absence of fever and parasitaemia. UB09 was shown to be relatively well‐conserved in nature. It is concluded that UB05, UB09 and the chimera UB05‐09 posses T‐cell epitopes that are associated with protection against malaria and could thus be used to distinguish SIS from FSS eventhough acute infection with malaria has been shown to reduce cytokine production in some studies. Further investigations of these antigens as potential diagnostic and/or vaccine candidates for malaria are indicated.
Low‐temperature concentration of tellurium and gold in continental red bed successions
Authors: Parnell John , Spinks Samuel , Bellis David
Published: March 2016

There is very little understanding of tellurium (Te) distribution and behaviour in sedimentary rocks. A suite of 15 samples of reduction spheroids (centimetre‐scale pale spheroids in otherwise red rock), including samples from eight localities in Triassic red beds across the British Isles, were mapped for Te using Laser Ablation–Inductively Coupled Plasma–Mass Spectrometry. Almost all showed enrichment in Te in the cores of the spheroids relative to background red bed concentrations, by up to four orders of magnitude. Some were also enriched over background in gold and/or mercury. In one case, discrete telluride minerals were recorded. The data show that Te is mobile and can be concentrated in low‐temperature sedimentary environments, controlled by redox variations. The consistency in enrichment across widely separate localities implies that the enrichment is a normal aspect of red bed diagenesis and so likely to be controlled by a ubiquitous process, such as microbial activity.
Identification of genetic variants associated with maize flowering time using an extremely large multi‐genetic background population
Authors: Li Yong‐xiang , Li Chunhui , Bradbury Peter J. , Liu Xiaolei , Lu Fei , Romay Cinta M. , Glaubitz Jeffrey C. , Wu Xun , Peng Bo , Shi Yunsu , Song Yanchun , Zhang Dengfeng , Buckler Edward S. , Zhang Zhiwu , Li Yu , Wang Tianyu
Published: March 2016

Flowering time is one of the major adaptive traits in domestication of maize and an important selection criterion in breeding. To detect more maize flowering time variants we evaluated flowering time traits using an extremely large multi‐ genetic background population that contained more than 8000 lines under multiple Sino‐United States environments. The population included two nested association mapping (NAM) panels and a natural association panel. Nearly 1 million single‐nucleotide polymorphisms (SNPs) were used in the analyses. Through the parallel linkage analysis of the two NAM panels, both common and unique flowering time regions were detected. Genome wide, a total of 90 flowering time regions were identified. One‐third of these regions were connected to traits associated with the environmental sensitivity of maize flowering time. The genome‐wide association study of the three panels identified nearly 1000 flowering time‐associated SNPs, mainly distributed around 220 candidate genes (within a distance of 1 Mb). Interestingly, two types of regions were significantly enriched for these associated SNPs – one was the candidate gene regions and the other was the approximately 5 kb regions away from the candidate genes. Moreover, the associated SNPs exhibited high accuracy for predicting flowering time.
Large‐scale atlas of microarray data reveals the distinct expression landscape of different tissues in Arabidopsis
Authors: He Fei , Yoo Shinjae , Wang Daifeng , Kumari Sunita , Gerstein Mark , Ware Doreen , Maslov Sergei
Published: March 2016

Transcriptome data sets from thousands of samples of the model plant Arabidopsis thaliana have been collectively generated by multiple individual labs. Although integration and meta‐analysis of these samples has become routine in the plant research community, it is often hampered by a lack of metadata or differences in annotation styles of different labs. In this study, we carefully selected and integrated 6057 Arabidopsis microarray expression samples from 304 experiments deposited to the Gene Expression Omnibus (GEO) at the National Center for Biotechnology Information (NCBI). Metadata such as tissue type, growth conditions and developmental stage were manually curated for each sample. We then studied the global expression landscape of the integrated data set and found that samples of the same tissue tend to be more similar to each other than to samples of other tissues, even in different growth conditions or developmental stages. Root has the most distinct transcriptome, compared with aerial tissues, but the transcriptome of cultured root is more similar to the transcriptome of aerial tissues, as the cultured root samples lost their cellular identity. Using a simple computational classification method, we showed that the tissue type of a sample can be successfully predicted based on its expression profile, opening the door for automatic metadata extraction and facilitating the re‐use of plant transcriptome data. As a proof of principle, we applied our automated annotation pipeline to 708 RNA‐seq samples from public repositories and verified the accuracy of our predictions with sample metadata provided by the authors.
High Temperature Lubricating Behavior of NiAl Matrix Composites With Addition of CuO
Authors: Zhu Shengyu , Cheng Jun , Qiao Zhuhui , Tian Yuan , Yang Jun
Published: March 2016

High temperature self-lubricating NiAl matrix composites with addition of CuO (15, 20, and 25 wt.%) were fabricated by powder metallurgy technique, and the tribological behavior from room temperature to 1000 °C was investigated. It was found that Ni–Cu and Al2O3 phases formed during the fabrication process due to reaction of NiAl and CuO. The tribological results showed that the composite with addition of 25 wt.% CuO has a favorable friction coefficient of about 0.2 and excellent wear resistance with the magnitude of 10−6 mm3 N−1 m−1 at high temperatures (800 and 1000 °C).
Thermophysical and Geometrical Effects on the Thermal Performance and Optimization of a Three-Dimensional Integrated Circuit
Authors: Tavakkoli Fatemeh , Ebrahimi Siavash , Wang Shujuan , Vafai Kambiz
Published: March 2016

A comprehensive analysis and optimization of a three-dimensional integrated circuit (3D IC) structure and its thermophysical attributes are presented in this work. The thermophysical and geometrical attributes studied in this paper include the die, device layer, heat sink, and heat spreader, which are critical structures within a 3D IC. The effect of the power density of the device layer which is the source of heat generation within the chip as well as the through silicon vias (TSV) and microbumps is also considered in our investigation. The thermophysical and geometrical parameters that have a significant impact on the thermal signature of the 3D IC as well as those that have an insignificant impact were established. The comprehensive analysis of different geometrical and thermophysical attributes can guide the design and optimization of a 3D IC structure and decrease the cost.
Investigation on Flowfield Characteristics and Performance of Shock Vector Control Nozzle Based on Confined Transverse Injection
Authors: Jingwei Shi , Li Zhou , Zhanxue Wang , Xiaolin Sun
Published: March 2016

Shock vector controlling (SVC) nozzle, based on confined transverse injection and shock wave/boundary layer interaction, offers an alternative for future aircraft thrust vectoring (TV) exhausting system, due to its simple structure, low weight, and quick vector response. In the paper, the flow mechanism of SVC nozzle was studied by numerical simulation after the validation of computational fluid dynamics (CFD) models was confirmed. Then, the influence of substantial affecting factors, including injection configurations and injection angles, on the confined transverse injection flowfield characteristics and vector performance was investigated numerically. The results show that the “λ” shock wave induced by the jet injection causes unbalanced side force for the primary flow deflecting, and under larger secondary pressure ratio (SPR), the induced shock wave interacts with upper wall, weakening the thrust vector efficiency; with the increase of injection orifice numbers, the vector angle of SVC nozzle rises and is less than that of slot injection configuration; under smaller SPR, the thrust vector angle increases with the injection angle. For the case of SPR = 1.0 and 1.2, there exist optimal injection angles at which the maximum TV angle achieved.
Numerical Study of the Effect of Nozzle Configurations on Characteristics of MILD Combustion for Gas Turbine Application
Authors: Deng Xiaowen , Xiong Yan , Yin Hong , Gao Qingshui
Published: March 2016

The MILD (moderate or intense low-oxygen dilution) combustion is characterized by low emission, stable combustion, and low noise for various kinds of fuel. This paper reports a numerical investigation of the effect of different nozzle configurations, such as nozzle number N, reactants jet velocity V, premixed and nonpremixed modes, on the characteristics of MILD combustion applied to one F class gas turbine combustor. An operating point is selected considering the pressure p = 1.63 MPa, heat intensity Pintensity = 20.5 MW/m3 atm, air preheated temperature Ta = 723 K, equivalence ratio φ = 0.625. Methane (CH4) is adopted as the fuel for combustion. Results show that low-temperature zone shrinks while the peak temperature rises as the nozzle number increases. Higher jet velocity will lead to larger recirculation ratio and the reaction time will be prolonged consequently. It is helpful to keep high combustion efficiency but can increase the NO emission obviously. It is also found that N = 12 and V = 110 m/s may be the best combination of configuration and operating point. The premixed combustion mode will achieve more uniform reaction zone, lower peak temperature, and pollutant emissions compared with the nonpremixed mode.
Technical and Economical Assessment of the Indirectly Heated Carbonate Looping Process
Authors: Junk Markus , Reitz Michael , Ströhle Jochen , Epple Bernd
Published: March 2016

Carbonate looping promises low energy penalties for postcombustion CO2-capture and is particularly suited for retrofitting existing power plants. To further improve the process, a new concept with an indirectly heated calciner using heat pipes was developed, offering even higher plant efficiencies and lower CO2 avoidance costs than the oxy-fired standard carbonate looping process. The concept of the indirectly heated carbonate looping (IHCL) process was tested at sufficient scale in a 300 kWth pilot plant at Technische Universität Darmstadt. The paper presents a technical overview of the process and shows first test results of the pilot plant. Furthermore, the concept is economically evaluated and compared to other carbon capture processes.
Quantum Dots-Converted Light-Emitting Diodes Packaging for Lighting and Display: Status and Perspectives
Authors: Xie Bin , Hu Run , Luo Xiaobing
Published: March 2016

Recent years, semiconductor quantum dots (QDs) have attracted tremendous attentions for their unique characteristics for solid-state lighting (SSL) and thin-film display applications. The pure and tunable spectra of QDs make it possible to simultaneously achieve excellent color-rendering properties and high luminous efficiency (LE) when combining colloidal QDs with light-emitting diodes (LEDs). Due to its solution-based synthetic route, QDs are impractical for fabrication of LED. QDs have to be incorporated into polymer matrix, and the mixture is dispensed into the LED mold or placed onto the LED to fabricate the QD–LEDs, which is known as the packaging process. In this process, the compatibility of QDs' surface ligands with the polymer matrix should be ensured, otherwise the poor compatibility can lead to agglomeration or surface damage of QDs. Besides, combination of QDs–polymer with LED chip is a key step that converts part of blue light into other wavelengths (WLs) of light, so as to generate white light in the end. Since QD-LEDs consist of three or more kinds of QDs, the spectra distribution should be optimized to achieve a high color-rendering ability. This requires both theoretical spectra optimization and experimental validation. In addition, to prolong the reliability and lifetime of QD-LEDs, QDs have to be protected from oxygen and moisture penetration. And the heat generation inside the package should be well controlled because high temperature results in QDs' thermal quenching, consequently deteriorates QD-LEDs' performance greatly. Overall, QD-LEDs' packaging and applications present the above-mentioned technical challenges. A profound and comprehensive understanding of these problems enables the advancements of QD-LEDs' packaging processes and designs. In this review, we summarized the recent progress in the packaging of QD-LEDs. The wide applications of QD-LEDs in lighting and display were overviewed, followed by the challenges and the corresponding progresses for the QD-LEDs' packaging. This is a domain in which significant progress has been achieved in the last decade, and reporting on these advances will facilitate state-of-the-art QD-LEDs' packaging and application technologies.
The Influence of Diluent Gases on Combustion Properties of Natural Gas: A Combined Experimental and Modeling Study
Authors: Richter Sandra , Ermel Jörn , Kick Thomas , Braun-Unkhoff Marina , Naumann Clemens , Riedel Uwe
Published: March 2016

Currently, new concepts for power generation are discussed, as a response to combat global warming due to CO2 emissions stemming from the combustion of fossil fuels. These concepts include new, low-carbon fuels as well as centralized and decentralized solutions. Thus, a more diverse range of fuel supplies will be used, with (biogenic) low-caloric gases such as syngas and coke oven gas (COG) among them. Typical for theses low-caloric gases is the amount of hydrogen, with a share of 50% and even higher. However, hydrogen mixtures have a higher reactivity than natural gas (NG) mixtures, burned mostly in today's gas turbine combustors. Therefore, in the present work, a combined experimental and modeling study of nitrogen-enriched hydrogen–air mixtures, some of them with a share of methane, to be representative for COG, will be discussed focusing on laminar flame speed data as one of the major combustion properties. Measurements were performed in a burner test rig at ambient pressure and at a preheat temperature T0 of 373 K. Flames were stabilized at fuel–air ratios between about φ = 0.5–2.0 depending on the specific fuel–air mixture. This database was used for the validation of four chemical kinetic reaction models, including an in-house one, and by referring to hydrogen-enriched NG mixtures. The measured laminar flame speed data of nitrogen-enriched methane–hydrogen–air mixtures are much smaller than the ones of nitrogen-enriched hydrogen–air mixtures. The grade of agreement between measured and predicted data depends on the type of flames and the type of reaction model as well as of the fuel–air ratio: a good agreement was found in the fuel lean and slightly fuel-rich regime; a large underprediction of the measured data exists at very fuel-rich ratios (φ > 1.4). From the results of the present work, it is obvious that further investigations should focus on highly nitrogen-enriched methane–air mixtures, in particular for very high fuel–air ratio (φ > 1.4). This knowledge will contribute to a more efficient and a more reliable use of low-caloric gases for power generation.
Effect of the Fuel Injection Strategy on Diesel Particulate Filter Regeneration in a Single-Cylinder Diesel Engine
Authors: Yoon Sungjun , Kim Hongsuk , Kim Daesik , Park Sungwook
Published: March 2016

Stringent emission regulations (e.g., Euro-6) have forced automotive manufacturers to equip a diesel particulate filter (DPF) on diesel cars. Generally, postinjection is used as a method to regenerate the DPF. However, it is known that postinjection deteriorates the specific fuel consumption and causes oil dilution for some operating conditions. Thus, an injection strategy for regeneration is one of the key technologies for diesel powertrains equipped with a DPF. This paper presents correlations between the fuel injection strategy and exhaust gas temperature for DPF regeneration. The experimental apparatus consists of a single-cylinder diesel engine, a DC dynamometer, an emission test bench, and an engine control system. In the present study, the postinjection timing was in the range of 40 deg aTDC to 110 deg aTDC and double postinjection was considered. In addition, the effects of the injection pressure were investigated. The engine load was varied among low load to midload conditions, and the amount of fuel of postinjection was increased up to 10 mg/stk. The oil dilution during the fuel injection and combustion processes was estimated by the diesel loss measured by comparing two global equivalences ratios: one measured from a lambda sensor installed at the exhaust port and one estimated from the intake air mass and injected fuel mass. In the present study, the differences of the global equivalence ratios were mainly caused by the oil dilution during postinjection. The experimental results of the present study suggest optimal engine operating conditions including the fuel injection strategy to obtain an appropriate exhaust gas temperature for DPF regeneration. The experimental results of the exhaust gas temperature distributions for various engine operating conditions are discussed. In addition, it was revealed that the amount of oil dilution was reduced by splitting the postinjection (i.e., double postinjection). The effects of the injection pressure on the exhaust gas temperature were dependent on the combustion phasing and injection strategies.
Pumping Unit Power-Density Improvement by Application of Counter-Rotating Impellers Design
Authors: Tosin Stefano , Friedrichs Jens , Dreiss Andreas
Published: March 2016

In many industrial areas, downsizing the pumping system is a decisive aim of the designers. The reasons could be multiple means; in a single-stage pump, increasing the power density of the pump means actually reducing the production costs. The main goal of this study was the comparison in terms of power density of a conventionally designed single-stage pump with a novel design concept based on the counter-rotating (CR) principle. In order to simplify the experimental investigations for the present study, the volute geometry was fixed instead of reducing the pump outflow diameters for a fixed design point. The energy concentration was then increased by raising the developed hydraulic power within the same envelope. The design of the impellers was carried out with an in-house design tool, based on inverse design method. Numerical results highlight the advantageousness of the new layout, in terms of power concentration, compared to the conventional impeller. Numerical predictions are also in significant agreement with the experimental investigation results, obtained in a specifically developed CR motors test rig. The experimental optimization of the rotational speed ratio of the CR impellers has shown the possibility to further increase the head in off-design condition and thereby the pump power density.
Loss and Deviation in Windmilling Fans
Authors: Gunn Ewan J. , Hall Cesare A.
Published: March 2016

For an unpowered turbofan in flight, the airflow through the engine causes the fan to freewheel. This paper considers the flow field through a fan operating in this mode, with emphasis on the effects of blade row losses and deviation. A control volume analysis is used to show that windmilling fans operate at a fixed flow coefficient which depends on the blade metal and deviation angles, while the blade row losses are shown to determine the fan mass flow rate. Experimental and numerical results are used to understand how the loss and deviation differ from the design condition due to the flow physics encountered at windmill. Results are presented from an experimental study of a windmilling low-speed rig fan, including detailed area traverses downstream of the rotor and stator. Three-dimensional computational fluid dynamics (CFD) calculations of the fan rig and a representative transonic fan windmilling at a cruise flight condition have also been completed. The rig test results confirm that in the windmilling condition, the flow through the fan stator separates from the pressure surface over most of the span. This generates high loss, and the resulting blockage changes the rotor work profile leading to modified rotational speed. In the engine fan rotor, a vortex forms at the pressure surface near the tip and further loss results from a hub separation caused by blockage from the downstream core and splitter.
3D microwave tomography of the breast using prior anatomical information
Authors: Golnabi Amir H. , Meaney Paul M. , Paulsen Keith D.
Published: March 2016

Purpose:

The authors have developed a new 3D breast image reconstruction technique that utilizes the soft tissue spatial resolution of magnetic resonance imaging (MRI) and integrates the dielectric property differentiation from microwave imaging to produce a dual modality approach with the goal of augmenting the specificity of MR imaging, possibly without the need for nonspecific contrast agents. The integration is performed through the application of a soft prior regularization which imports segmented geometric meshes generated from MR exams and uses it to constrain the microwave tomography algorithm to recover nearly uniform property distributions within segmented regions with sharp delineation between these internal subzones.

Methods:

Previous investigations have demonstrated that this approach is effective in 2D simulation and phantom experiments and also in clinical exams. The current study extends the algorithm to 3D and provides a thorough analysis of the sensitivity and robustness to misalignment errors in size and location between the spatial prior information and the actual data.

Results:

Image results in 3D were not strongly dependent on reconstruction mesh density, and the changes of less than 30% in recovered property values arose from variations of more than 125% in target region size—an outcome which was more robust than in 2D. Similarly, changes of less than 13% occurred in the 3D image results from variations in target location of nearly 90% of the inclusion size. Permittivity and conductivity errors were about 5 times and 2 times smaller, respectively, with the 3D spatial prior algorithm in actual phantom experiments than those which occurred without priors.

Conclusions:

The presented study confirms that the incorporation of structural information in the form of a soft constraint can considerably improve the accuracy of the property estimates in predefined regions of interest. These findings are encouraging and establish a strong foundation for using the soft prior technique in clinical studies, where their microwave imaging system and MRI can simultaneously collect breast exam data in patients.
An explicit analytical solution for sound propagation in a three-dimensional penetrable wedge with small apex angle
Authors: Petrov Pavel S. , Sturm Frédéric
Published: March 2016

A problem of sound propagation in a shallow-water waveguide with a weakly sloping penetrable bottom is considered. The adiabatic mode parabolic equations are used to approximate the solution of the three-dimensional (3D) Helmholtz equation by modal decomposition of the acoustic pressure field. The mode amplitudes satisfy parabolic equations that admit analytical solutions in the special case of the 3D wedge. Using the analytical formula for modal amplitudes, an explicit and remarkably simple expression for the acoustic pressure in the wedge is obtained. The proposed solution is validated by the comparison with a solution of the 3D penetrable wedge problem obtained using a fully 3D parabolic equation that includes a leading-order cross term correction.
Nuclear envelope rupture and repair during cancer cell migration
Authors: Denais Celine M. , Gilbert Rachel M. , Isermann Philipp , McGregor Alexandra L. , te Lindert Mariska , Weigelin Bettina , Davidson Patricia M. , Friedl Peter , Wolf Katarina , Lammerding Jan
Published: March 2016

Repairing tears in the nuclear envelope

The nuclear envelope segregates genomic DNA from the cytoplasm and regulates protein trafficking between the cytosol and the nucleus. Maintaining nuclear envelope integrity during interphase is considered crucial. However, Raab
et al.
and Denais
et al.
show that migrating immune and cancer cells experience frequent and transitory nuclear envelope ruptures when they move through tight spaces (see the Perspective by Burke). The nuclear envelope reseals rapidly during interphase, assisted by components of the ESCRT III membrane-remodeling machinery.

Science
, this issue pp.
359
and
353
; see also p.
295
Homogeneously dispersed multimetal oxygen-evolving catalysts
Authors: Zhang Bo , Zheng Xueli , Voznyy Oleksandr , Comin Riccardo , Bajdich Michal , García-Melchor Max , Han Lili , Xu Jixian , Liu Min , Zheng Lirong , García de Arquer F. Pelayo , Dinh Cao Thang , Fan Fengjia , Yuan Mingjian , Yassitepe Emre , Chen Ning , Regier Tom , Liu Pengfei , Li Yuhang , De Luna Phil , Janmohamed Alyf , Xin Huolin L. , Yang Huagui , Vojvodic Aleksandra , Sargent Edward H.
Published: March 2016

Modulating metal oxides

The more difficult step in fuel cells and water electrolysis is the oxygen evolution reaction. The search for earth-abundant materials to replace noble metals for this reaction often turns to oxides of three-dimensional metals such as iron. Zhang
et al.
show that the applied voltages needed to drive this reaction are reduced for iron-cobalt oxides by the addition of tungsten. The addition of tungsten favorably modulates the electronic structure of the oxyhydroxide. A key development is to keep the metals well mixed and avoid the formation of separate phases.

Science
, this issue p.
333