bluuebunny/crossref_metadata_2025 huggingface dataset:
Triassic to Early Jurassic (c. 200 Ma) UHP metamorphism in the Central Rhodopes: evidence from U–Pb–Th dating of monazite in diamond‐bearing gneiss from Chepelare (Bulgaria)
Authors: Petrík I. , Janák M. , Froitzheim N. , Georgiev N. , Yoshida K. , Sasinková V. , Konečný P. , Milovská S.
Published: January 2016

Evidence for ultrahigh‐pressure metamorphism (UHPM) in the Rhodope metamorphic complex comes from occurrence of diamond in pelitic gneisses, variably overprinted by granulite facies metamorphism, known from several areas of the Rhodopes. However, tectonic setting and timing of UHPM are not interpreted unanimously. Linking age to a metamorphic stage is a prerequisite for reconstruction of these processes. Here, we use monazite in diamond‐bearing gneiss from Chepelare (Bulgaria) to date the diamond‐forming UHPM event in the Central Rhodopes. The diamond‐bearing gneiss comes from a strongly deformed, lithologically heterogeneous zone (Chepelare Mélange) sandwiched between two migmatized orthogneiss units, known as Arda‐I and Arda‐II. Diamond, identified by Raman micro‐spectroscopy, shows the characteristic band mostly centred between 1332 and 1330 cm−1. The microdiamond occurs as single grains or polyphase diamond + carbonate inclusions, rarely with CO2. Thermodynamic modelling shows that garnet was stable at UHP conditions of 3.5–4.6 GPa and 700–800 °C, in the stability field of diamond, and was re‐equilibrated at granulite facies/partial melting conditions of 0.8–1.2 GPa and 750–800 °C. The texture of monazite shows older central parts and extensive younger domains which formed due to metasomatic replacement in solid residue and/or overgrowth in melt domains. The monazite core compositions, with distinctly lower Y, Th and U contents, suggest its formation in equilibrium with garnet. The U–Th–Pb dating of monazite using electron microprobe analysis yielded a c. 200 Ma age for the older cores with low Th, Y, U and high La/Nd ratio, and a c. 160 Ma age for the dominant younger monazite enriched in Th, Y, U and HREE. The older age of c. 200 Ma is interpreted as the timing of UHPM, whereas the younger age of c. 160 Ma as granulite facies/partial melting overprint. Our results suggest that UHPM occurred in Late Triassic to Early Jurassic time, in the framework of collision and subduction of continental crust after the closure of Paleotethys.
Carbetocin is a Functional Selective Gq Agonist That Does Not Promote Oxytocin Receptor Recycling After Inducing β‐Arrestin‐Independent Internalisation
Authors: Passoni I. , Leonzino M. , Gigliucci V. , Chini B. , Busnelli M.
Published: January 2016

Carbetocin, a long‐acting oxytocin analogue, has been reported to elicit interesting and peculiar behavioural effects. The present study investigated the molecular pharmacology of carbetocin, aiming to better understand the molecular basis of its action in the brain. Using bioluminescence resonance energy transfer biosensors, we characterised the effects of carbetocin on the three human oxytocin/vasopressin receptors expressed in the nervous system: the oxytocin receptor (OXTR) and the vasopressin V1a (V1aR) and V1b (V1bR) receptors. Our results indicate that (i) carbetocin activates the OXTR but not the V1aR and V1bR at which it may act as an antagonist; (ii) carbetocin selectively activates only the OXTR/Gq pathway displaying a strong functional selectivity; (iii) carbetocin is a partial agonist at the OXTR/Gq coupling; (iv) carbetocin promotes OXTR internalisation via a previously unreported β‐arrestin‐independent pathway; and (v) carbetocin does not induce OXTR recycling to the plasma membrane. Altogether, these molecular pharmacology features identify carbetocin as a substantially different analogue compared to the endogenous oxytocin and, consequently, carbetocin is not expected to mimic oxytocin in the brain. Whether these unique features of carbetocin could be exploited therapeutically remains to be established.
Social variables exert selective pressures in the evolution and form of primate mimetic musculature
Authors: Burrows Anne M. , Li Ly , Waller Bridget M. , Micheletta Jerome
Published: January 2016

Mammals use their faces in social interactions more so than any other vertebrates. Primates are an extreme among most mammals in their complex, direct, lifelong social interactions and their frequent use of facial displays is a means of proximate visual communication with conspecifics. The available repertoire of facial displays is primarily controlled by mimetic musculature, the muscles that move the face. The form of these muscles is, in turn, limited by and influenced by phylogenetic inertia but here we use examples, both morphological and physiological, to illustrate the influence that social variables may exert on the evolution and form of mimetic musculature among primates. Ecomorphology is concerned with the adaptive responses of morphology to various ecological variables such as diet, foliage density, predation pressures, and time of day activity. We present evidence that social variables also exert selective pressures on morphology, specifically using mimetic muscles among primates as an example. Social variables include group size, dominance ‘style’, and mating systems. We present two case studies to illustrate the potential influence of social behavior on adaptive morphology of mimetic musculature in primates: (1) gross morphology of the mimetic muscles around the external ear in closely related species of macaque (Macaca mulattaandMacaca nigra) characterized by varying dominance styles and (2) comparative physiology of the orbicularis oris muscle among select ape species. This muscle is used in both facial displays/expressions and in vocalizations/human speech. We present qualitative observations of myosin fiber‐type distribution in this muscle of siamang (Symphalangus syndactylus), chimpanzee (Pan troglodytes), and human to demonstrate the potential influence of visual and auditory communication on muscle physiology. In sum, ecomorphologists should be aware of social selective pressures as well as ecological ones, and that observed morphology might reflect a compromise between the demands of the physical and the social environments.
The Taste of Plate: How the Spiciness of Food is Affected by the Color of the Plate Used to Serve It
Authors: Tu Yangjun , Yang Zhi , Ma Chaoqun
Published: January 2016

By focusing on a solid spicy food product and the trigeminal perception of spiciness, the present work aimed to test the effect of plate color on spiciness. Three experiments investigated the influence of color (red, yellow, green or white) on spiciness expectations (Experiment 1), the influence of color (red or white) on actual perceived spiciness (Experiment 2) and the mediation effect of spiciness expectations on the influence of color (red or white) on actual perceived spiciness (Experiment 3). Results showed that plate color exerted a significant influence on people's spiciness expectations and sense of actual perceived spiciness. In particular, the spicy bean curd presented on a red plate was perceived as significantly spicier than when presented on a green or white plate, while the spicy bean curd presented on a white plate was perceived as significantly less spicy than when presented on a red or yellow plate. Spiciness expectations significantly mediated the influence of color on actual perceived spiciness; participants expected, and consequently actually perceived, the same food product's spiciness as more intense when served on a red plate rather than on a white plate.

Practical Applications

This research provides information on how the color characteristics of the plate on which a solid spicy food was served affected participants’ expected spiciness for that food as well as their sense of its actual perceived spiciness. This research also provides information on how participants’ sense of actual perceived spiciness was mediated by their spiciness expectations for particular color–spiciness associations. Spicy food producers as well as restaurants, bars and supermarkets could use this information to boost sales through enhancing consumers’ flavor experiences of spicy foods by more intentionally selecting and designing packaging and differentiating the color characteristics of the food products themselves to enhance their levels of expected and actual perceived spiciness.
Support vector regression to estimate the permeability enhancement of potential transdermal enhancers
Authors: Shah Alpa , Sun Yi , Adams Rod G , Davey Neil , Wilkinson Simon C , Moss Gary P
Published: January 2016

Objectives

Searching for chemicals that will safely enhance transdermal drug delivery is a significant challenge. This study applies support vector regression (SVR) for the first time to estimating the optimal formulation design of transdermal hydrocortisone formulations.

Methods

The aim of this study was to apply SVR methods with two different kernels in order to estimate the enhancement ratio of chemical enhancers of permeability.

Key findings

A statistically significant regression SVR model was developed. It was found that SVR with a nonlinear kernel provided the best estimate of the enhancement ratio for a chemical enhancer.

Conclusions

Support vector regression is a viable method to develop predictive models of biological processes, demonstrating improvements over other methods. In addition, the results of this study suggest that a global approach to modelling a biological process may not necessarily be the best method and that a ‘mixed-methods’ approach may be best in optimising predictive models.
Co-extrusion as a processing technique to manufacture a dual sustained release fixed-dose combination product
Authors: Vynckier An-Katrien , Voorspoels Jody , Remon Jean Paul , Vervaet Chris
Published: January 2016

Objectives

This study aimed to design a fixed-dose combination dosage form which provides a sustained release profile for both the freely water-soluble metformin HCl and the poorly soluble gliclazide, two antidiabetic compounds used to treat diabetes mellitus.

Methods

Hot-melt co-extrusion was used as an innovative manufacturing technique for a pharmaceutical fixed-dose combination product. In this way, a matrix formulation that sustained metformin release could be developed, despite the high drug load in the formulation and the freely soluble nature of the drug.

Key findings

It was clear that co-extrusion was perfectly suited to produce a fixed-dose combination product with adequate properties for each of the incorporated APIs. A coat layer, containing at least 30% CAPA® 6506 as a hydrophobic polymer, was necessary to adequately sustain the release of the highly dosed freely soluble drug from the 70% metformin HCl-loaded CAPA® 6506 core of the co-extrudate. To obtain a complete gliclazide release over 24-h solubilization in Kollidon® VA, added as a second polymer to the CAPA® 6506 in the coat, was needed.

Conclusions

Both active pharmaceutical ingredients (APIs), which have different physicochemical characteristics, were formulated in a single dosage form, using co-extrusion.
Jagged1 inhibits osteoprotegerin expression by human periodontal ligament cells
Authors: Manokawinchoke J. , Sumrejkanchanakij P. , Subbalekha K. , Pavasant P. , Osathanon T.
Published: January 2016

Background and Objective

Notch signaling regulates bone homeostasis. The present study investigated the effect of Jagged1 on osteoprotegerin (OPG) and receptor activator of nuclear factor kappa‐B ligand (RANKL) expression in human periodontal ligament stromal (hPDL) cells.

Material and Methods

hPDL cells were seeded on to indirect immobilized Jagged1 surfaces. OPG expression was determined using real‐time polymerase chain reaction and enzyme‐linked immunosorbent assay. Lentiviral small hairpin RNA particles against NOTCH2 were employed to inhibit NOTCH2 expression. Osteoclast formation was evaluated using RAW264.7 cells. An influence of exogenous OPG on osteogenic differentiation was determined by real‐time polymerase chain reaction and Alizarin Red S staining.

Results

Jagged1 significantly enhanced HES1 and HEY1mRNA expression in a dose‐dependent manner. Furthermore, OPG mRNA and protein levels dramatically decreased upon exposing hPDL cells to Jagged1. However, RANKL mRNA levels were not significantly different. There was also no difference in M‐CSF and MCP‐1mRNA expression. A γ‐secretase inhibitor and cycloheximide treatment rescued Jagged1‐attenuated OPG expression. Furthermore, shNOTCH2 overexpressing hPDL cells did not exhibit a decrease in OPG expression upon exposure to Jagged1, implying the involvement of NOTCH2 in the regulatory mechanism. Culturing RAW264.7 cells with conditioned medium from Jagged1‐treated hPDL cells enhanced osteoclast formation compared with those cultured with conditioned medium of the control group. Lastly, OPG treatment did not influence osteogenic differentiation by hPDL cells.

Conclusion

These results suggest that Jagged1 activates Notch signaling in hPDL cells, leading to decreased OPG expression. This may imply an indirect role of Jagged1 on the regulation of osteoclast differentiation via hPDL cells.
Climate and the distribution of grasses in West Africa
Authors: Bocksberger Gaëlle , Schnitzler Jan , Chatelain Cyrille , Daget Philippe , Janssen Thomas , Schmidt Marco , Thiombiano Adjima , Zizka Georg
Published: January 2016

Questions

Which environmental variables influence grass diversity in West Africa? What are the effects of climate and grass functional traits on the spatial patterns (richness and abundance) of the grass clades Andropogoneae, Paniceae and Chloridoideae?

Location

West Africa, demarcated by the Atlantic Ocean in the west and south (20° W and 4° N), the Sahara desert in the north (25° N) and the border between Niger and Chad in the east (20° E).

Methods

Based on 38 912 georeferenced occurrence records, we modelled the distribution of 302 grass species (51% of West African grass diversity). We integrated species richness, abundance and functional traits (life cycle, photosynthetic type and height) to determine the contribution of the most speciose grass clades (Andropogoneae, Paniceae and Chloridoideae) to overall grass diversity in West Africa.

Results

Precipitation is the variable most often influencing the species distribution models of grasses in West Africa. Richness and relative abundance of the tribe Andropogoneae show a centre of diversity in Sudanian savanna regions. The height of Andropogoneae species, generally >150 cm, is driving this ecological dominance. Species richness of the tribe Paniceae is more dispersed and shows two main centres of abundance: The southern regions with higher mean annual precipitation and tree density are dominated by C3 Paniceae species. The Sahelian regions in the north are dominated by short Paniceae species with the C4 NAD‐ME photosynthetic subtype, as well as Chloridoideae possessing the same functional attributes.

Conclusions

Our study provides insight into the environmental correlates of grass species richness in West Africa and contributes to the much‐needed research on tropical rangelands. Moreover, the integration of evolutionary history significantly improves our understanding of large‐scale biodiversity patterns.
Altered trafficking of abnormal prion protein in atypical scrapie: prion protein accumulation in oligodendroglial inner mesaxons
Authors: Jeffrey M. , González L. , Simmons M. M , Hunter N. , Martin S. , McGovern G.
Published: January 2016

Aims

Prion diseases exist in classical and atypical disease forms. Both forms are characterized by disease‐associated accumulation of a host membrane sialoglycoprotein known as prion protein (PrPd). In classical forms of prion diseases, PrPd can accumulate in the extracellular space as fibrillar amyloid, intracellularly within lysosomes, but mainly on membranes in association with unique and characteristic membrane pathology. These membrane changes are found in all species and strains of classical prion diseases and consist of spiral, branched and clathrin‐coated membrane invaginations on dendrites. Atypical prion diseases have been described in ruminants and man and have distinct biological, biochemical and pathological properties when compared to classical disease. The purpose of this study was to determine whether the subcellular pattern of PrPd accumulation and membrane changes in atypical scrapie were the same as those found in classical prion diseases.

Methods

Immunogold electron microscopy was used to examine brains of atypical scrapie‐affected sheep and Tg338 mice.

Results

Classical prion disease‐associated membrane lesions were not found in atypical scrapie‐affected sheep, however, white matter PrPd accumulation was localized mainly to the inner mesaxon and paranodal cytoplasm of oligodendroglia. Similar lesions were found in myelinated axons of atypical scrapie Tg338‐infected mice. However, Tg338 mice also showed the unique grey matter membrane changes seen in classical forms of disease.

Conclusions

These data show that atypical scrapie infection directs a change in trafficking of abnormal PrP to axons and oligodendroglia and that the resulting pathology is an interaction between the agent strain and host genotype.
Genotypic differences in storage losses of sugar beet – causes and indirect criteria for selection
Authors: Schnepel Katharina , Hoffmann Christa M.
Published: January 2016

To improve the storability of sugar beets, this study aimed at determining reasons for genotypic variability in sugar losses and invert sugar accumulation during storage, and at identifying indirect criteria to select for varieties with low storage losses prior to storage. In 2011 and 2012, 18 genotypes, and in 2012 and 2013, six genotypes cultivated at two locations were stored for 8 and 12 weeks at 8°C under controlled conditions. The same 18 genotypes were grown under stress conditions in Spain in 2012/2013. Sugar losses were closely correlated with the invert sugar accumulation after storage. Genotypic differences in storage losses were primarily caused by differences in the level of infestation with microorganisms. The invert sugar accumulation was lower for genotypes with high marc concentration before storage, pointing to a non‐specific resistance. Additionally, the sugar concentration in dry matter before storage, and the invert sugar concentration after cultivation under stress conditions correlated with the invert sugar concentration after storage. These parameters are therefore suggested as criteria to select for improved storability of sugar beet genotypes.
Reduced severity of posttraumatic stress disorder associated with Val allele of Val66Met polymorphism at brain‐derived neurotrophic factor gene among Chinese adolescents after Wenchuan earthquake
Authors: Li Rong Hui , Fan Mei , Hu Min Shan , Ran Mao Sheng , Fang Ding Zhi
Published: January 2016

The aim of the present study was to longitudinally investigate the association of BDNF Val66Met with PTSD symptoms in Chinese Han adolescents who experienced the 2008 Wenchuan earthquake. Variants of BDNF Val66Met were identified by polymerase chain reaction‐restriction fragment length polymorphism analyses and verified by DNA sequencing. PTSD symptoms were assessed by the PTSD Checklist–Civilian Version (PCL‐C) among high school students at 6, 12, and 18 months after the earthquake. No differences of PTSD prevalence and PCL‐C scores were found between the Val/Val homozygotes and the Met allele carriers at 6, 12, and 18 months after the earthquake regardless of gender. Decreased PTSD prevalence was observed at 12 and 18 months when compared with that at 6 months after the earthquake regardless of gender and the genotype. Meanwhile, PCL‐C scores were decreased consecutively in the female subjects regardless of the genotypes. However, the scores at 18 months were lower when compared with those at 12 months in the male Val/Val homozygotes, but not in the male Met allele carriers. In addition, differences were found for the predictors of PCL‐C scores and PTSD prevalence between the Val/Val homozygotes and the Met allele carriers during follow‐up. These findings suggest that the association of BDNF Val66Met with PTSD is longitudinally different in Chinese Han adolescents after the 2008 Wenchuan earthquake. The Val allele may be associated with reduced PTSD severity in male adolescents in the later stage of PTSD rehabilitation during follow‐up.
Cusums for tracking arbitrary functionals
Authors: Withers Christopher S. , Nadarajah Saralees
Published: January 2016

Cusum charts are widely used for detecting deviations of a process about a target value and also for finding evidence of change in the mean of a process. The testing theory approximates the process by a Wiener process or a Brownian bridge, respectively. For quality control, it is important that other aspects are monitored in addition to or instead of the mean. Here, we show that cusum theory is easily adapted when the target is not the mean but some other aspect of the distribution.
Five Questions (with their Answers) on ER‐Associated Degradation
Authors: Brambilla Pisoni Giorgia , Molinari Maurizio
Published: January 2016

Production of a functional proteome is a major burden for our cells. Native proteins operate inside and outside the cells to eventually warrant life and adaptation to metabolic and environmental changes, there is no doubt that production and inappropriate handling of misfolded proteins may cause severe disease states. This review focuses on protein destruction, which is, paradoxically, a crucial event for cell and organism survival. It regulates the physiological turnover of proteins and the clearance of faulty biosynthetic products. It mainly relies on the intervention of two catabolic machineries, the ubiquitin proteasome system and the (auto)lysosomal system. Here, we have selected five questions dealing with how, why and when proteins produced in the mammalian endoplasmic reticulum are eventually selected for destruction.
Mitogenomic phylogeny of Acanthocephala reveals novel Class relationships
Authors: Gazi Mohiuddin , Kim Jiyeon , García‐Varela Martín , Park Chungoo , Littlewood D. Tim J. , Park Joong‐Ki
Published: January 2016

The Acanthocephala is a phylum of obligate endoparasitic animals comprising four classes (Archiacanthocephala, Palaeacanthocephala, Eoacanthocephala and Polyacanthocephala), although the phylogenetic interrelationships of these classes still remains unresolved. To investigate phylogenetic relationships of major acanthocephalan groups, we characterized the complete mitochondrial genome sequences of two palaeacanthocephalan species Centrorhynchus aluconis and Prosthorhynchus transversus (representing two different families of the order Polymorphida), and Polyacanthorhynchus caballeroi (the first mitogenomic representative of the class Polyacanthocephala) and used these new sequences for phylogenetic analyses, along with 32 platyzoan mtDNAs, including 10 additional acanthocephalans. Phylogenetic analyses using concatenated amino acid sequences for 12 protein‐coding genes with maximum likelihood and Bayesian inference methods supported monophyly of Acanthocephala. Within the phylum, Archiacanthocephala was positioned as the sister to the clade containing all three other acanthocephalan classes, with the polyacanthocephalan species P. caballeroi nested within Eoacanthocephala. This result contradicts morphology‐based classification systems that treated polyacanthorhynchids as one of the palaeacanthocephalan families, and instead suggests Polyacanthocephala is a member of Eoacanthocephala. Within the Palaeacanthocephala, Polymorphida monophyly was strongly supported and this is inconsistent with nuclear rDNA‐based molecular hypotheses that suggest non‐monophyly.
Shear stress activates monovalent cation channel transient receptor potential melastatin subfamily 4 in rat atrial myocytes via type 2 inositol 1,4,5‐trisphosphate receptors and Ca2+ release
Authors: Son Min‐Jeong , Kim Joon‐Chul , Kim Sung Woo , Chidipi Bojjibabu , Muniyandi Jeyaraj , Singh Thoudam Debraj , So Insuk , Subedi Krishna P. , Woo Sun‐Hee
Published: January 2016

Key points

During each contraction and haemodynamic disturbance, cardiac myocytes are subjected to fluid shear stress as a result of blood flow and the relative movement of sheets of myocytes.

The present study aimed to characterize the shear stress‐sensitive membrane current in atrial myocytes using the whole‐cell patch clamp technique, combined with pressurized fluid flow, as well as pharmacological and genetic interventions of specific proteins.

The data obtained suggest that shear stress indirectly activates the monovalent cation current carried by transient receptor potential melastatin subfamily 4 channels via type 2 inositol 1,4,5‐trisphosphate receptor‐mediated Ca2+ release in subsarcolemmal domains of atrial myocytes.

Ca2+‐mediated interactions between these two proteins under shear stress may be an important mechanism by which atrial cells measure mechanical stress and translate it to alter their excitability.

Atrial myocytes are subjected to shear stress during the cardiac cycle under physiological or pathological conditions. The ionic currents regulated by shear stress remain poorly understood. We report the characteristics, molecular identity and activation mechanism of the shear stress‐sensitive current (Ishear) in rat atrial myocytes. A shear stress of ∼16 dyn cm−2 was applied to single myocytes using a pressurized microflow system, and the current was measured by whole‐cell patch clamp. In symmetrical CsCl solutions with minimal concentrations of internal EGTA, Ishear showed an outwardly rectifying current–voltage relationship (reversal at −2 mV). The current was conducted primarily (∼80%) by monovalent cations but not Ca2+. It was suppressed by intracellular Ca2+ buffering at a fixed physiological level, inhibitors of transient receptor potential melastatin subfamily 4 (TRPM4), intracellular introduction of TRPM4 antibodies or knockdown of TRPM4 expression, suggesting that TRPM4 carries most of this current. A notable reduction in Ishear occurred upon inhibition of Ca2+ release through the ryanodine receptors or inositol 1,4,5‐trisphosphate receptors (IP3R) and upon depletion of sarcoplasmic reticulum Ca2+. In type 2 IP3R (IP3R2) knockout atrial myocytes, Ishear was 10–20% of that in wild‐type myocytes. Immunocytochemistry and proximity ligation assays revealed that TRPM4 and IP3R2 were expressed at peripheral sites with co‐localization, although they are not localized within 40 nm. Peripheral localization of TRPM4 was intact in IP3R2 knockout cells. The data obtained in the present study suggest that shear stress activates TRPM4 current by triggering Ca2+ release from the IP3R2 in the peripheral domains of atrial myocytes.
The involvement of transient receptor potential canonical type 1 in skeletal muscle regrowth after unloading‐induced atrophy
Authors: Xia Lu , Cheung Kwok‐Kuen , Yeung Simon S. , Yeung Ella W.
Published: January 2016

Key points

Decreased mechanical loading results in skeletal muscle atrophy. The transient receptor potential canonical type 1 (TRPC1) protein is implicated in this process. Investigation of the regulation of TRPC1 in vivo has rarely been reported. In the present study, we employ the mouse hindlimb unloading and reloading model to examine the involvement of TRPC1 in the regulation of muscle atrophy and regrowth, respectively.

We establish the physiological relevance of the concept that manipulation of TRPC1 could interfere with muscle regrowth processes following an atrophy‐inducing event. Specifically, we show that suppressing TRPC1 expression during reloading impairs the recovery of the muscle mass and slow myosin heavy chain profile. Calcineurin appears to be part of the signalling pathway involved in the regulation of TRPC1 expression during muscle regrowth.

These results provide new insights concerning the function of TRPC1. Interventions targeting TRPC1 or its downstream or upstream pathways could be useful for promoting muscle regeneration.

Decreased mechanical loading, such as bed rest, results in skeletal muscle atrophy. The functional consequences of decreased mechanical loading include a loss of muscle mass and decreased muscle strength, particularly in anti‐gravity muscles. The purpose of this investigation was to clarify the regulatory role of the transient receptor potential canonical type 1 (TRPC1) protein during muscle atrophy and regrowth. Mice were subjected to 14 days of hindlimb unloading followed by 3, 7, 14 and 28 days of reloading. Weight‐bearing mice were used as controls. TRPC1 expression in the soleus muscle decreased significantly and persisted at 7 days of reloading. Small interfering RNA (siRNA)‐mediated downregulation of TRPC1 in weight‐bearing soleus muscles resulted in a reduced muscle mass and a reduced myofibre cross‐sectional area (CSA). Microinjecting siRNA into soleus muscles in vivo after 7 days of reloading provided further evidence for the role of TRPC1 in regulating muscle regrowth. Myofibre CSA, as well as the percentage of slow myosin heavy chain‐positive myofibres, was significantly lower in TRPC1‐siRNA‐expressing muscles than in control muscles after 14 days of reloading. Additionally, inhibition of calcineurin (CaN) activity downregulated TRPC1 expression in both weight‐bearing and reloaded muscles, suggesting a possible association between CaN and TRPC1 during skeletal muscle regrowth.
An Examination of Motorcycle Antilock Brake Systems in Reducing Crash Risk
Authors: Fowler Graeme F. , Ray Rose M. , Huang Su-Wei , Zhao Ke , Frank Todd A.
Published: January 2016

To prevent wheel lockup (and possible loss-of-control and capsize) during hard braking, motorcycle manufacturers have equipped motorcycles with antilock brake systems (ABS) either as an option or as standard equipment. Several studies utilizing real-world crash data have been published, which estimate the effectiveness of motorcycle ABS in reducing the risk of a crash based on varying assumptions. These investigations have reported mixed results. The present investigation relies upon the fatality analysis reporting system (FARS) and the Florida police-reported crash databases to further investigate the effectiveness of motorcycle ABS by expanding upon and refining previous approaches. Notably, a case-control approach is used, whereby crashes involving ABS- and non-ABS-equipped motorcycles are divided into five groups with a varying likelihood that ABS will affect the risk of crashes in that group. The group of crashes with the least likelihood of being influenced by ABS is considered the control group and used as a measure of exposure to crashes. This methodology attempts to reduce any selection biases that might exist in the two motorcycle classes. The results support the hypothesis that ABS is effective in reducing the crash risk in some crash types. However, it was found that the case-control approach does not incorporate all factors that might influence the overall effectiveness of ABS, e.g., motorcycle class and operator age. Accounting for these additional factors would likely require the use of regression analyses and would benefit significantly from additional data.
PowerGen Gas Turbine Losses and Condition Monitoring: A Loss Data-Based Study
Authors: Zhou Bin
Published: January 2016

In situ condition monitoring (CM) is a crucial element in protection and predictive maintenance of large rotating PowerGen equipment, such as gas turbines or steam turbines. In this work, selected gas turbine loss events occurring during a recent 10-year period at our clients’ power generation plants were evaluated. For each loss event, a loss scenario or a chain of failures was outlined after investigating the available loss record. These loss events were then categorized based on the nature of the associated loss scenario. The study subsequently focused on the variables that could be monitored in real-time to detect the abnormal turbine operating conditions, such as vibration characteristics, temperature, pressure, quality of working fluids, and material degradations. These groups of CM variables were then matched with detectable failures in each loss event and prioritized based on their effectiveness for failure detection and prevention. The detectable loss events and the associated loss values were used in this evaluation process. The study finally concluded with a summary of findings and path-forward actions.
Uncertainty Quantification of Time-Dependent Reliability Analysis in the Presence of Parametric Uncertainty
Authors: Hu Zhen , Mahadevan Sankaran , Du Xiaoping
Published: January 2016

Limited data of stochastic load processes and system random variables result in uncertainty in the results of time-dependent reliability analysis. An uncertainty quantification (UQ) framework is developed in this paper for time-dependent reliability analysis in the presence of data uncertainty. The Bayesian approach is employed to model the epistemic uncertainty sources in random variables and stochastic processes. A straightforward formulation of UQ in time-dependent reliability analysis results in a double-loop implementation procedure, which is computationally expensive. This paper proposes an efficient method for the UQ of time-dependent reliability analysis by integrating the fast integration method and surrogate model method with time-dependent reliability analysis. A surrogate model is built first for the time-instantaneous conditional reliability index as a function of variables with imprecise parameters. For different realizations of the epistemic uncertainty, the associated time-instantaneous most probable points (MPPs) are then identified using the fast integration method based on the conditional reliability index surrogate without evaluating the original limit-state function. With the obtained time-instantaneous MPPs, uncertainty in the time-dependent reliability analysis is quantified. The effectiveness of the proposed method is demonstrated using a mathematical example and an engineering application example.
Model-Form Calibration in Drift-Diffusion Simulation Using Fractional Derivatives
Authors: Wang Yan
Published: January 2016

In modeling and simulation, model-form uncertainty arises from the lack of knowledge and simplification during the modeling process and numerical treatment for ease of computation. Traditional uncertainty quantification (UQ) approaches are based on assumptions of stochasticity in real, reciprocal, or functional spaces to make them computationally tractable. This makes the prediction of important quantities of interest, such as rare events, difficult. In this paper, a new approach to capture model-form uncertainty is proposed. It is based on fractional calculus, and its flexibility allows us to model a family of non-Gaussian processes, which provides a more generic description of the physical world. A generalized fractional Fokker–Planck equation (fFPE) is used to describe the drift-diffusion processes under long-range correlations and memory effects. A new model-calibration approach based on the maximum mutual information is proposed to reduce model-form uncertainty, where an optimization procedure is taken.
Performance Characterization of a Capacitive Deionization Water Desalination System With an Intermediate Solution and Low Salinity Water
Authors: Salamat Yasamin , Rios Perez Carlos A. , Hidrovo Carlos
Published: January 2016

In recent years, more efforts have been made to improve new and more efficient nonmembrane-based methods for water desalination. Capacitive deionization (CDI), a novel technique for water desalination using an electric field to adsorb ions from a solution to a high-porous media, has the capability to recover a fraction of the energy consumed for the desalination during the regeneration process, which happens to be its most prominent characteristic among other desalination methods. This paper introduces a new desalination method that aims at improving the performance of traditional CDI systems. The proposed process consists of an array of CDI cells connected in series with buffer containers in between them. Each buffer serves two purposes: (1) averaging the outlet solution from the preceding cell and (2) securing a continuous water supply to the following cell. Initial evaluation of the proposed CDI system architecture was made by comparing a two-cell-one-buffer assembly with a two cascaded cells array. Concentration of the intermediate solution buffer was the minimum averaged concentration attained at the outlet of the first CDI cell, under a steady-state condition. The obtained results show that the proposed CDI system with intermediate solution had better performance in terms of desalination percentage. This publication opens new opportunities to improve the performance of CDI systems and implement this technology on industrial applications.
Numerical Investigation of Mini Wind Turbines Near Highways
Authors: Lapointe Caelan , Gopalan Harish
Published: January 2016

High-speed vehicle motion on the highways produces localized winds whose energy can be harnessed. These local winds have less variability especially if the highway traffic is constant. The idea of extracting energy from highway winds has been conceptualized in many studies before. However, the feasibility of this idea has never been tested using analytical, computation, or experimental methods. In this study, we numerically compute the amount of power that can be extracted from local highway winds due to vehicular motion. A unsteady Reynolds-averaged Navier–Stokes (URANS) method is used for modeling the atmospheric boundary layer (ABL). Realistic computer-aided design (CAD) models of cars and trucks separated by spacing information obtained from the existing standards are used to model the vehicle motion. A vertical axis wind turbine (VAWT) is used for extracting energy from the wind. The entire framework of ABL, vehicles, and turbine is simulated using overset grids and multiple translating and rotating frames of reference. Many vehicle motion scenarios were compared to the case of an isolated wind turbine. The initial results show a significant increase in the power that can be extracted by these turbines. The average extracted power increases about 317% when compared to the case without any vehicular motion. Field measurements or wind tunnel studies are required to provide validation for the computations and to determine if more advanced turbulence modeling methodologies have to be employed for these studies.
Temperature Solution for Transient Heat Conduction in a Thin Bilayer Between Semi-Infinite Media in Thermal Effusivity Measurement
Authors: van der Tempel Leendert
Published: January 2016

A series expansion and an approximation have been derived for the temperature in the general case of transient heat conduction in two thin layers between two semi-infinite media at different uniform initial temperatures. The temperature accuracy and thermal effusivity measurement accuracy have been mapped to establish a window of operation for direct thermal effusivity measurement by the modified transient plane source (MTPS) method. The presented temperature series enables quick thermal analysis of thermally thick and semithick samples without factory correction/calibration.
Constitutive Modeling of Brain Tissue: Current Perspectives
Authors: de Rooij Rijk , Kuhl Ellen
Published: January 2016

Modeling the mechanical response of the brain has become increasingly important over the past decades. Although mechanical stimuli to the brain are small under physiological conditions, mechanics plays a significant role under pathological conditions including brain development, brain injury, and brain surgery. Well calibrated and validated constitutive models for brain tissue are essential to accurately simulate these phenomena. A variety of constitutive models have been proposed over the past three decades, but no general consensus on these models exists. Here, we provide a comprehensive and structured overview of state-of-the-art modeling of the brain tissue. We categorize the different features of existing models into time-independent, time-dependent, and history-dependent contributions. To model the time-independent, elastic behavior of the brain tissue, most existing models adopt a hyperelastic approach. To model the time-dependent response, most models either use a convolution integral approach or a multiplicative decomposition of the deformation gradient. We evaluate existing constitutive models by their physical motivation and their practical relevance. Our comparison suggests that the classical Ogden model is a well-suited phenomenological model to characterize the time-independent behavior of the brain tissue. However, no consensus exists for mechanistic, physics-based models, neither for the time-independent nor for the time-dependent response. We anticipate that this review will provide useful guidelines for selecting the appropriate constitutive model for a specific application and for refining, calibrating, and validating future models that will help us to better understand the mechanical behavior of the human brain.
Geometric Design and Construction of Structurally Stabilized Accordion Shelters
Authors: Lee Ting-Uei , Gattas Joseph M.
Published: January 2016

Accordion patterns are widely used for deployable shelters, due to their simple construction, elegant deployment mechanism, and folded plate form with an inherent structural efficiency. This paper proposes two new accordion-type shelters that use modified geometries to improve on the structural stability and stiffness of the typical accordion form. The first shelter is termed a distributed frame accordion shelter and is generated by separating fully folded accordion frames between spacer plates aligned with the transverse direction. A transverse stiffness and increased flexural rigidity can therefore be achieved while maintaining a nonzero floor area. The second shelter is termed a diamond wall accordion shelter and is generated by inserting secondary wall elements that increase wall sectional depth and counteract the coupled rotational-transverse displacements at accordion roof–wall junctions. For both shelter types, a geometric parameterization and a full-scale prototype are presented. Good correlation is seen between the designed and constructed surfaces. A numerical investigation also shows that the new forms have substantially increased flexural rigidities compared to the typical accordion form.
Comparison of Different Strategies for Heliostats Aiming Point in Cavity and External Tower Receivers
Authors: Binotti Marco , De Giorgi Paolo , Sanchez David , Manzolini Giampaolo
Published: January 2016

This paper investigates different strategies for the reduction of peak heat fluxes on the receiver of a solar tower plant through the variation of the heliostats aiming points. The analysis is performed for two different solar tower receivers and heliostat field layouts. The innovative aspect of the work is in the methodology proposed: the effect of different aiming points is evaluated at different sun positions, and the yearly optical efficiency is calculated to determine drawbacks in terms of energy production. The optical simulation of the solar plant is performed with delsol through a matlab suite to easily manage the input and output. Preliminary assessments showed that the most important displacement is the vertical one, and the variation of the aiming point is important for the rows that are closer to the tower. With the appropriate strategy, the peak heat flux can be reduced by about 40% with limited spillage increase compared to the reference case. This result is similar for the two investigated plants, and it is confirmed also at different sun positions. The yearly optical efficiency with the optimal aiming strategy is reduced by less than 0.5% points. Future analysis will assess potential cost reductions and thermal efficiency increase brought about by the proposed strategies.
Numerical Analysis of Thermal Stratification in Large Horizontal Thermal Energy Storage Tanks
Authors: Shaarawy Maikel , Lightstone Marilyn
Published: January 2016

This paper presents the results of a numerical study on the thermal performance of large horizontal thermal energy storage tanks. The numerical model was validated using measurements obtained from Drake Landing Solar Community (DLSC), which is located in Alberta, Canada. A total of seven different baffle configurations were assessed for a range of operating conditions. Characterization of the tank performance was done by monitoring the tank outlet temperature and computing the Huhn efficiency, which is a characterization index based on the second law of thermodynamics. Results show that the current tanks at DLSC experience excessive mixing due to fluid entrainment from the inlet jet. A newly introduced design that confines the inlet jet mixing shows the potential to enhance the level of stratification during charging or discharging at a constant temperature. In addition, most designs tested have a relatively high level of stratification during charging, discharging, and simultaneous charging and discharging, but fail to sustain the level of stratification when a positive buoyant jet is introduced.
Film Cooling Parameter Waveforms on a Turbine Blade Leading Edge Model With Oscillating Stagnation Line
Authors: Rutledge James L. , Rathsack Tylor C. , Van Voorhis Matthew T. , Polanka Marc D.
Published: January 2016

It is necessary to understand how film cooling influences the external convective boundary condition involving both the adiabatic wall temperature and the heat transfer coefficient in order to predict the thermal durability of a gas turbine hot gas path component. Most studies in the past have considered only steady flow, but studies of the unsteadiness naturally present in turbine flow have become more prevalent. One source of unsteadiness is wake passage from upstream components which can cause fluctuations in the stagnation location on turbine airfoils. This in turn causes unsteadiness in the behavior of the leading edge coolant jets and thus fluctuations in both the adiabatic effectiveness and heat transfer coefficient. The dynamics of h and η are now quantifiable with modern inverse heat transfer methods and nonintrusive infrared thermography. The present study involved the application of a novel inverse heat transfer methodology to determine time-resolved adiabatic effectiveness and heat transfer coefficient waveforms on a simulated turbine blade leading edge with an oscillating stagnation position. The leading edge geometry was simulated with a circular cylinder with a coolant hole located 21.5 deg downstream from the leading edge stagnation line, angled 20 deg to the surface and 90 deg to the streamwise direction. The coolant plume is shown to shift in response to the stagnation line movement. These oscillations thus influence the film cooling coverage, and the time-averaged benefit of film cooling is influenced by the oscillation.
Numerical Investigation of Kelvin–Helmholtz Instability in a Centrifugal Compressor Operating Near Stall
Authors: Bousquet Y. , Binder N. , Dufour G. , Carbonneau X. , Trebinjac I. , Roumeas M.
Published: January 2016

The present work details the occurrence of the Kelvin–Helmholtz instability in a centrifugal compressor operating near stall. The analysis is based on unsteady three-dimensional simulations performed on a calculation domain covering the full annulus for the impeller and the vaned diffuser. A detailed investigation of the flow structure is presented, together with its evolution consequent to the mass flow reduction. It is demonstrated that this reduction leads to an enlargement of the low-momentum flow region initially induced by the combination of the secondary and leakage flows. When the compressor operates near stall, the shear layer at the interface between the main flow and this low-momentum flow becomes unstable and induces a periodic vortex shedding. The frequency of such an unsteady phenomenon is not correlated with the blade-passing frequency. Its signature is thus easily isolated from the deterministic rotor/stator interaction. Its detection requires full-annulus simulations with an accurate resolution in time and space, which explains why it has never been previously observed in centrifugal compressors.