bluuebunny/crossref_metadata_2025 huggingface dataset:
Decreases in Mineralocorticoid but not Glucocorticoid Receptor mRNA Expression During the Short Arctic Breeding Season in Free‐Living Gambel's White‐Crowned Sparrow (Zonotrichia leucophrys gambelii)
Authors: Krause J. S. , McGuigan M. A. , Bishop V. R. , Wingfield J. C. , Meddle S. L.
Published: November 2014

The acute stress response in vertebrates is a highly adaptive suite of physiological and behavioural mechanisms that promote survival in the face of deleterious stimuli from the environment. Facultative changes of physiology and behaviour are mediated through changes in circulating levels of glucocorticoids (corticosterone, cortisol) and their subsequent binding to the high‐affinity mineralocorticoid receptor (MR) or the low‐affinity glucocorticoid receptor (GR). Free‐living male wild Gambel's white‐crowned sparrows (Zonotrichia leucophrys gambelii) display annual fluctuations in the stress response with marked attenuation during the transition from the pre‐parental to the parental stage. We investigated whether this rapid reduction in the stress response is mediated through changes in MR and GR mRNA expression in the brain using in situ hybridisation. MR mRNA expression was found to be significantly lower in the hippocampus as the male birds became parental. No changes were observed in GR mRNA expression in the paraventricular nucleus (PVN) or preoptic area (POA) at this time. No significant correlations were found between initial capture levels of corticosterone and GR or MR mRNA expression. No differences were found in basal levels of corticosterone between pre‐parental and parental in birds collected for in situ hybridisation. Stress response data revealed no difference at baseline but reductions in peak levels of corticosterone as birds became parental. These data suggest that changes in MR expression may be important for the regulation of the stress response or behavioural stress sensitivity with respect to promoting parental care and investment.
Effect of different hydroxyapatite incorporation methods on the structural and biological properties of porous collagen scaffolds for bone repair
Authors: Ryan Alan J. , Gleeson John P. , Matsiko Amos , Thompson Emmet M. , O'Brien Fergal J.
Published: November 2014

Scaffolds which aim to provide an optimised environment to regenerate bone tissue require a balance between mechanical properties and architecture known to be conducive to enable tissue regeneration, such as a high porosity and a suitable pore size. Using freeze‐dried collagen‐based scaffolds as an analogue of native ECM, we sought to improve the mechanical properties by incorporating hydroxyapatite (HA) in different ways while maintaining a pore architecture sufficient to allow cell infiltration, vascularisation and effective bone regeneration. Specifically we sought to elucidate the effect of different hydroxyapatite incorporation methods on the mechanical, morphological, and cellular response of the resultant collagen‐HA scaffolds. The results demonstrated that incorporating either micron‐sized (CHA scaffolds) or nano‐sized HA particles (CnHA scaffolds) prior to freeze‐drying resulted in moderate increases in stiffness (2.2‐fold and 6.2‐fold, respectively, vs. collagen‐glycosaminoglycan scaffolds, P < 0.05, a scaffold known to support osteogenesis), while enabling good cell attachment, and moderate mesenchymal stem cell (MSC)‐mediated calcium production after 28 days' culture (2.1‐fold, P < 0.05, and 1.3‐fold, respectively, vs. CG scaffolds). However, coating of collagen scaffolds with a hydroxyapatite precipitate after freeze‐drying (CpHA scaffolds) has been shown to be a highly effective method to increase the compressive modulus (26‐fold vs. CG controls, P < 0.001) of scaffolds while maintaining a high porosity (~ 98%). The coating of the ligand‐dense collagen structure results in a lower cell attachment level (P < 0.05), although it supported greater cell‐mediated calcium production (P < 0.0001) compared with other scaffold variants after 28 days' culture. The comparatively good mechanical properties of these high porosity scaffolds is obtained partially through highly crosslinking the scaffolds with both a physical (DHT) and chemical (EDAC) crosslinking treatment. Control of scaffold microstructure was examined via alterations in freezing temperature. It was found that the addition of HA prior to freeze‐drying generally reduced the pore size and so the CpHA scaffold fabrication method offered increased control over the resulting scaffolds microstructure. These findings will help guide future design considerations for composite biomaterials and demonstrate that the method of HA incorporation can have profound effects on the resulting scaffold structural and biological response.
Dilated cardiomyopathy in children: Review of all presentations to a children's hospital over a 5‐year period and the impact of family cardiac screening
Authors: Herath Verangi CK , Gentles Thomas L , Skinner Jonathan R
Published: November 2014

Aim

This study aims to report the aetiology and outcome of dilated cardiomyopathy (DCM) in children from New Zealand and to assess the outcome of protocolised family cardiac investigation introduced in 2007.

Methods

Retrospective review of all patients with DCM, aged <15 years, presenting to the children's hospital between 01/01/2007 and 01/03/2012. Oncology patients were excluded. Family screening results were assessed.

Results

Thirty‐five patients were identified. Median age 1 year: 26/35 (74%) <5 years. Ethnicity: New Zealand European 14/35 (40%), Maori 11/35 (31%), Pacific Island 5/35 (14%) and other 5/35(14%). Excluding the four cases with biopsy‐proven myocarditis, family cardiac screening was documented in 15/31 (48%). Of these, 7/15 (47%) had a positive family screen. Six previously undiagnosed DCM cases were found in these families. Five of the seven familial DCM cases had evidence of viral infection at presentation. Final aetiology: Myocarditis, 15/35 (43%), with Parvovirus being the commonest virus identified 10/15(67%). Familial, seven (20%), Idiopathic, seven (20%), Others, six (17%). Overall outcome was death 10/35(28%), ongoing dysfunction 16/35 (46%) and normalisation in 9/35 (26%). The median time to death from diagnosis was 1.5 months (3 days to 3 years). Death occurred in 4/7 with familial DCM (57%) compared with 6/28 (21%) among the others (ns). Recovery occurred in 0/7 with familial DCM versus 4/4 with biopsy proven myocarditis (P < 0.05).

Conclusions

Almost half of families screened had evidence of familial DCM, and these children carried a worse prognosis. Maori and Pacific Island children seem to be over‐represented. Family investigation led to the identification of many pre‐symptomatic individuals even when viral aetiology was suspected initially.
Patterns of complementary and alternative medicine (CAM) use among dental patients
Authors: Kummet Colleen M. , Spector Michael L. , Dawson Deborah V. , Fischer Mark , Holmes David C. , Warren John , Nisly Nicole L.
Published: November 2014

Objectives

Complementary and alternative medicine (CAM) is a diverse collection of approaches used to prevent or treat diseases. The goal of this study was to examine relationships between dental patient characteristics and current usage of CAM therapies.

Methods

The CAM definition encompassed 24 therapies excluding prayer. Associations and trends in usage were assessed for gender, income, education, and age. Multivariable logistic and negative binomial models were used to identify factors impacting the use and number of CAM therapies used.

Results

In dental patients (n = 402), nearly 67 percent of subjects reported at least one CAM treatment. Gender was significantly associated with recent utilization of CAM, biological, manipulative (all P < 0.01), and mind–body (P = 0.04) therapies, as well as the number (P < 0.01) of therapies used. Higher education levels were significant in usage of any CAM, biological, and mind–body therapies (P < 0.01).

Conclusion

A large proportion of dental patients reported use of CAM therapies. While CAM therapies and those who use them are diverse, given their widespread use, they clearly have potential impacts on the oral health of the public. Knowledge of the characteristics of dental patients who use CAM therapies is a first step in developing a broader understanding how CAM therapies and associated beliefs may affect oral health and public health programs.
Effect of Chronic Administration of PDE5 Combined with Glycemic Control on Erectile Function in Streptozotocin-Induced Diabetic Rats
Authors: Choi Woo Suk , Kwon Oh Seong , Cho Sung Yong , Paick Jae-Seung , Kim Soo Woong
Published: November 2014

Introduction

Chronic treatment with phosphodiesterase type 5 inhibitors (PDE5) is effective in an animal model of diabetes-induced erectile dysfunction (DMED). In addition, recent research indicates that glycemic control can restore DMED.

Aims

We evaluated the effect of chronic administration of PDE5 combined with glycemic control on DMED.

Methods

Sprague-Dawley rats (8 weeks old) were divided into five groups (n = 10 each): normal control (C), diabetes (DM), DM treated with insulin (DM-I), DM treated with PDE5 (DM-P), and DM treated with insulin and PDE5 (DM-I + P). Rats in the diabetic groups received an injection of streptozotocin (45 mg/kg). After 10 weeks of induced diabetes, the DM-I group was treated with a daily injection of neutral protamine Hagedorn, and the DM-P group was treated with a daily dosage of 20 mg/kg PDE5 (DA-8159) for 4 weeks. The DM-I + P group was treated with both treatments simultaneously. After 14 weeks of induced diabetes, an evaluation of erectile function and histological and biochemical markers of corporal tissue was performed.

Main Outcome Measures

Erectile function and histological and biochemical markers in corporal tissue.

Results

Rats in the DM group showed markedly lower erectile parameters than those in the C group, whereas rats in the DM-I and DM-P groups showed intermediate erectile function between the DM and C groups. Rats in the DM-I + P group showed restored erectile function, comparable with group C. A comparison of apoptotic index, expression of the endothelial marker, and phosphorylation of endothelial nitric oxide synthase and Akt displayed a similar pattern with the results from cavernosometry (DM < DM-I = DM-P < DM-I + P = C, P < 0.05). The distribution of phosphorylated myosin phosphatase target subunit 1 was in the reverse order.

Conclusions

Chronic administration of PDE5 or glycemic control with insulin resulted in restoration of overt DMED. The combination of both treatments was superior to monotherapy with insulin or PDE5.
Congruent signals of population history but radically different patterns of genetic diversity between mitochondrial and nuclear markers in a mountain lizard
Authors: Ferchaud Anne‐Laure , Eudeline Rémy , Arnal Véronique , Cheylan Marc , Pottier Gilles , Leblois Raphaël , Crochet Pierre‐André
Published: November 2014

Historical factors, current population size, population connectivity and selective processes at linked loci contribute to shaping contemporary patterns of neutral genetic diversity. It is now widely acknowledged that nuclear and mitochondrial markers react differently to current demography as well as to past history, so the use of both types of markers is often advocated to gain insight on both historical and contemporary processes. We used 12 microsatellite loci genotyped in 13 populations of a mountain lizard (Iberolacerta bonnali) to test whether the historical scenario favoured by a previous mitochondrial study was also supported by nuclear markers and thereby evaluated the consequences of postglacial range movements on nuclear diversity. Congruent signals of recent history were revealed by nuclear and mitochondrial markers using an Approximate Bayesian computation approach, but contemporary patterns of mtDNA and nuclear DNA diversity were radically different. Although dispersal in this species is probably highly restricted at all spatial scales, colonization abilities have been historically good, suggesting capability for reestablishment of locally extinct populations except in fully disconnected habitats.
Literate Actions, Reading Attitudes, and Reading Achievement: Interconnections Across Languages for Adolescent Learners of English in Korea
Authors: Lee Juhee , Schallert Diane L.
Published: November 2014

Using the three components of attitude in Fishbein and Ajzen's (1975) Reasoned Action Theory—cognition (personal and evaluative beliefs), affect (feelings, emotions), and conation (behavioral intentions)—the present study investigated relations among L1 and L2 reading attitudes, the relative contributions of reading attitude and language proficiency to reading achievement, and various factors that shape L2 reading attitude. Participants were 289 middle school students studying English in Korea. Their language proficiency, reading achievement, and reading attitudes in L1 and L2 were measured. Results indicated that measures of L1 reading attitude factors correlated with scores on the corresponding L2 reading attitude factor. Despite the correlations between cross‐linguistic reading attitudes, reading attitudes in L1 and L2 exhibited different tendencies. Both cognitive attitude and language proficiency predicted L1 reading comprehension, whereas language proficiency was the sole contributor to L2 reading achievement. Reading frequency significantly contributed to reading attitude and achievement scores in L1, but such patterns were not as clearly apparent in L2. Also, proficiency in both L1 and L2 was associated with more positive reading attitudes and fewer negative feelings about reading in the corresponding language. Finally, several factors predicted L2 reading attitude: access to books, length of private instruction, teachers' encouragement, and participant gender.
Effects of Variations in Reading Span Task Design on the Relationship Between Working Memory Capacity and Second Language Reading
Authors: Alptekin Cem , Erçetin Gülcan , Özemir Oya
Published: November 2014

Relationships between working memory (WM)—measured by reading span tasks (RSTs)—and second language (L2) reading are explored by probing the effects of differences in secondary task design (semantic vs. morphosyntactic) and the language of the task (first or second). Participants were 98 Turkish late adult learners of English as an L2 with moderate proficiency in the language. They completed a reading comprehension test in English and four RSTs (two in Turkish, two in English) whose processing tasks required judging whether there was an anomaly, morphosyntactic or semantic, depending on the RST. Exploratory factor analysis indicated that the storage component of span tasks loaded on the same factor, suggesting that storage is task‐ and language‐independent. By contrast, L2 learners' processing was affected by the linguistic nature of the task and the language in which it was presented. Additionally, findings point to a significant relationship between L2 reading and learners' storage capacity. As for processing, resources underlying L1 and L2 semantic and L2 morphosyntactic processes contribute to L2 reading, unlike those underlying L1 morphosyntactic processes. These findings attenuate the notion of construct equivalency in WM measurement through RSTs, dependent on secondary task type and language used.
Linking nonstructural carbohydrate dynamics to gas exchange and leaf hydraulic behavior in Pinus edulis and Juniperus monosperma
Authors: Woodruff David R. , Meinzer Frederick C. , Marias Danielle E. , Sevanto Sanna , Jenkins Michael W. , McDowell Nate G.
Published: November 2014

Leaf hydraulics, gas exchange and carbon storage in Pinus edulis and Juniperus monosperma, two tree species on opposite ends of the isohydry–anisohydry spectrum, were analyzed to examine relationships between hydraulic function and carbohydrate dynamics.

Leaf hydraulic vulnerability, leaf water potential (Ψl), leaf hydraulic conductance (Kleaf), photosynthesis (A), stomatal conductance (gs) and nonstructural carbohydrate (NSC) content were analyzed throughout the growing season.

Leaf hydraulic vulnerability was significantly lower in the relatively anisohydric J. monosperma than in the more isohydric P. edulis. In P. edulis, Ψl dropped and stayed below 50% loss of leaf hydraulic conductance (P50) early in the day during May, August and around midday in September, leading to sustained reductions in Kleaf. In J. monosperma, Ψl dropped below P50 only during August, resulting in the maintenance of Kleaf during much of the growing season. Mean A and gs during September were significantly lower in P. edulis than in J. monosperma. Foliar total NSC was two to three times greater in J. monosperma than in P. edulis in June, August and September.

Consistently lower levels of total NSC in P. edulis suggest that its isohydric strategy pushes it towards the exhaustion of carbon reserves during much of the growing season.
Consequences of obesity and weight loss: a devil's advocate position
Authors: Brown R. E. , Kuk J. L.
Published: November 2014

Obesity is associated with multiple negative health consequences and current weight management guidelines recommend all obese persons to lose weight. However, recent evidence suggests that not all obese persons are negatively affected by their weight and that weight loss does not necessarily always improve health. The purpose of this review is not to trivialize the significant health risks associated with obesity, but to discuss subpopulations of obese people who are not adversely affected, or may even benefit from higher adiposity, and in who weight loss per se may not always be the most appropriate recommendation. More specifically, this review will take a devil's advocate position when discussing the consequences of obesity and weight loss for adults with established cardiovascular disease and type 2 diabetes, weight cyclers, metabolically healthy obese adults, youth, older adults and obese individuals who are highly fit.
A case of endocapillary proliferative glomerulonephritis with macrophages phagocytosing monoclonal immunoglobulin lambda light chain
Authors: Watanabe Hirofumi , Osawa Yutaka , Goto Shin , Habuka Masato , Imai Naofumi , Ito Yumi , Hirose Takayuki , Chou Takaaki , Ohashi Ryuji , Shimizu Akira , Ehara Takashi , Shimotori Takashi , Narita Ichiei
Published: November 2014

Multiple myeloma (MM) is a plasma‐cell neoplasm that can cause renal disorders. Renal lesions in MM can present with a very rare pathological manifestation involving a specific monoclonal immunoglobulin (Ig). We report the case of a 33‐year‐old woman who had edema, fatigue, elevated serum creatinine levels, hypoalbuminemia, and hypercholesterolemia. She had persistent hematuria and proteinuria lasting 3 years. Serum protein electrophoresis showed an M‐spike, and serum immunofixation demonstrated the presence of monoclonal IgG λ. She had proteinuria in the nephrotic range, and a monoclonal λ fragment was present on urine immunofixation. Renal biopsy showed proliferative glomerulonephritis with λ light chain and C3c deposition and inflammatory cell infiltration with CD68. Macrophage lysosomes contained λ light chains, suggesting their partial phagocytosis. She was diagnosed with symptomatic MM and was treated with bortezomib and dexamethasone and an autologous peripheral stem cell transplant conditioned with intravenous melphalan. She achieved a partial response with decreased serum monoclonal protein and improved renal function. This case may be categorized as a monoclonal gammopathy‐associated proliferative glomerulonephritis. The biopsy finding of partially phagocytosed Ig λ light chains by macrophages is very rare; this pathological condition is similar to crystal‐storing histiocytosis.
Role of Arginine decarboxylase (ADC) in Arabidopsis thaliana defence against the pathogenic bacterium Pseudomonas viridiflava
Authors: Rossi F. R. , Marina M. , Pieckenstain F. L.
Published: November 2014

Polyamine biosynthesis starts with putrescine production through the decarboxylation of arginine or ornithine. In Arabidopsis thaliana, putrescine is synthesised exclusively by arginine decarboxylase (ADC), which exists as two isoforms (ADC1 and 2) that are differentially regulated by abiotic stimuli, but their role in defence against pathogens has not been studied in depth. This work analysed the participation of ADC in Arabidopsis defence against Pseudomonas viridiflava. ADC activity and expression, polyamine levels and bacterial resistance were analysed in null mutants of each ADC isoform. In non‐infected wild‐type (WT) plants, ADC2 expression was much higher than ADC1. Analysis of adc mutants demonstrated that ADC2 contributes to a much higher extent than ADC1 to basal ADC activity and putrescine biosynthesis. In addition, adc2 mutants showed increased basal expression of salicylic acid‐ and jasmonic acid‐dependent PR genes. Bacterial infection induced putrescine accumulation and ADC1 expression in WT plants, but pathogen‐induced putrescine accumulation was blocked in adc1 mutants. Results suggest a specific participation of ADC1 in defence, although basal resistance was not decreased by dysfunction of either of the two ADC genes. In addition, and as opposed to WT plants, bacterial infection increased ADC2 expression and ADC activity in adc1 mutants, which could counterbalance the lack of ADC1. Results demonstrate a major contribution of ADC2 to total ADC activity and the specific induction of ADC1 in response to infection. A certain degree of functional redundancy between the two isoforms in relation to their contribution to basal resistance is also evident.
Advancing Policy Theory with Cultural Theory: An Introduction to the Special Issue
Authors: Swedlow Brendon
Published: November 2014

Cultural Theory (CT) is a constructivist theory, developed by Mary Douglas, Aaron Wildavsky, and others, that seeks to participate in the positivist project of discovering, explaining, and predicting regularities in human behavior. Special Issue contributions and this introduction suggest some ways in which this theory can help advance policy studies. One way CT can help is by further specifying other approaches to policy theory. Thus, Hank Jenkins‐Smith and his collaborators argue (and with respect to belief systems demonstrate) that the theory can be used to specify belief systems, coalitions, and causes of policy change in the Advocacy Coalition Framework (ACF); Rob Robinson uses CT to specify further both sources of resistance to policy change and sources of dramatic policy change in Punctuated Equilibrium Theory (PET); and Christopher Weare, Paul Lichterman, and Nicole Esparza use the theory to specify sources of collaboration in policy networks as well as sources of network dissolution. Other contributors argue and/or demonstrate that CT can help specify the culturally pluralized conditions for successful policy deliberation, the cultural sources of policy narratives, and how cultural biases are likely to interact with policy frames. This Special Issue invites policy scholars to consider how the theory might help advance their research interests and the field.
Cultural Theory and the Measurement of Deep Core Beliefs Within the Advocacy Coalition Framework
Authors: Ripberger Joseph T. , Gupta Kuhika , Silva Carol L. , Jenkins‐Smith Hank C.
Published: November 2014

Deep core beliefs represent an important yet theoretically underspecified concept within the Advocacy Coalition Framework (ACF). This underspecification can (in part) be attributed to the ad hoc way in which ACF scholars have defined and measured the concept over time. To overcome this, we advocate the development and future use of a standardized metric for measuring deep core beliefs in ACF studies. Such a measure, we contend, should be multidimensional, generalizable, measurable using multiple techniques, and broad enough in scope to operate across virtually all policy domains. Using these criteria as our benchmark, we evaluate the viability of cultural theory (CT) as one such metric. In short, we find that CT meets all of these criteria, and therefore provides ACF scholars with a way to measure deep core beliefs across enduring public policy disputes that are demarcated by conflicting belief systems. Accordingly, we advocate its use in future studies.
Culture and Legal Policy Punctuation in the Supreme Court's Gender Discrimination Cases
Authors: Robinson Rob
Published: November 2014

For the most part, punctuated equilibrium scholarship has ignored the legal policy change generated by the Supreme Court. In this study, I address this gap though an examination of the Court's equal protection and gender cases from the 1970s. My case study here has two aims. First, I offer an adaptation of the jurisprudential regimes framework as a device for framing and identifying legal policy punctuations. After identifying Reed v. Reed (1971) as the cut point of such a regime, I then use Reed and its progeny to illustrate the promise of culture in explaining stasis and change, specifically focusing on the concepts of cultural cognition and cultural surprise.
Is there still hope for single therapies: How do we set up experimental systems to efficiently test combination therapies?
Authors: Joos Guy F. , Gabazza Esteban C.
Published: November 2014

Severe asthma, chronic obstructive pulmonary disease (COPD) and idiopathic pulmonary fibrosis (IPF) are chronic lung diseases with a clear need for development of new and more efficient therapy. In preclinical research, the mouse model has been instrumental in advancing our knowledge of the biology and immunology. However, it has been proven rather difficult and time consuming to develop new treatments that can impact on the clinical course of these diseases. Many challenges need to be overcome for upgrading the quality of currently available experimental disease models in order to enhance the translation rate of basic research to clinical practice. Establishment of transgenic mouse overexpressing disease‐causing genes may provide tools to discover new pathological pathways and to evaluate the possibility of molecular targeted therapy in chronic lung diseases. Personalized medicine, if developed, might be the solution for ‘disease heterogeneity’ and for improving clinical outcome.
Peritoneal Cavity is a Route for Gut‐Derived Microbial Signals to Promote Autoimmunity in Non‐Obese Diabetic Mice
Authors: Emani R. , Alam C. , Pekkala S. , Zafar S. , Emani M. R. , Hänninen A.
Published: November 2014

Macrophages play a crucial role in innate immune reactions, and peritoneal macrophages (PMs) guard the sterility of this compartment mainly against microbial threat from the gut. Type 1 diabetes (T1D) is an autoimmune disease in which gut microbiota and gut immune system appear to contribute to disease pathogenesis. We have recently reported elevated free radical production and increased permeability of gut epithelium in non‐obese diabetic (NOD) mice. Impaired barrier function could lead to bacterial leakage to the peritoneal cavity. To explore the consequences of impaired gut barrier function on extra‐intestinal immune regulation, we characterized peritoneal lavage cells from young newly weaned NOD mice. We detected a rapid increase in the number of macrophages 1–2 weeks after weaning in NOD mice compared to C57BL/6 and BALB/c mice. Interestingly, this increase in macrophages was abrogated in NOD mice that were fed an antidiabetogenic diet (ProSobee), which improves gut barrier function. Macrophages in young (5‐week‐old) NOD mice displayed a poor TNF‐α cytokine response to LPS stimulation and high expression of interleukin‐1receptor‐associated kinase‐M (IRAK‐M), indicating prior in vivo exposure to TLR‐4 ligand(s). Furthermore, injection of LPS intraperitoneally increased T cell CD69 expression in pancreatic lymph node (PaLN), suggestive of T cell activation. Leakage of bacterial components such as endotoxins into the peritoneal cavity may contribute to auto‐reactive T cell activation in the PaLN.
The trxG family histone methyltransferase SET DOMAIN GROUP 26 promotes flowering via a distinctive genetic pathway
Authors: Berr Alexandre , Shafiq Sarfraz , Pinon Violaine , Dong Aiwu , Shen Wen‐Hui
Published: November 2014

Histone methylation is a major component in numerous processes such as determination of flowering time, which is fine‐tuned by multiple genetic pathways that integrate both endogenous and environmental signals. Previous studies identified SET DOMAIN GROUP 26 (SDG26) as a histone methyltransferase involved in the activation of flowering, as loss of function of SDG26 caused a late‐flowering phenotype in Arabidopsis thaliana. However, the SDG26 function and the underlying molecular mechanism remain largely unknown. In this study, we undertook a genetic analysis by combining the sdg26 mutant with mutants of other histone methylation enzymes, including the methyltransferase mutants Arabidopsis trithorax1 (atx1), sdg25 and curly leaf (clf), as well as the demethylase double mutant lsd1‐like1 lsd1‐like2 (ldl1 ldl2). We found that the early‐flowering mutants sdg25, atx1 and clf interact antagonistically with the late‐flowering mutant sdg26, whereas the late‐flowering mutant ldl1 ldl2 interacts synergistically with sdg26. Based on microarray analysis, we observed weak overlaps in the genes that were differentially expressed between sdg26 and the other mutants. Our analyses of the chromatin of flowering genes revealed that the SDG26 protein binds at the key flowering integrator SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1/AGAMOUS‐LIKE 20 (SOC1/AGL20), and is required for histone H3 lysine 4 trimethylation (H3K4me3) and histone H3 lysine 36 trimethylation (H3K36me3) at this locus. Together, our results indicate that SDG26 promotes flowering time through a distinctive genetic pathway, and that loss of function of SDG26 causes a decrease in H3K4me3 and H3K36me3 at its target gene SOC1, leading to repression of this gene and the late‐flowering phenotype.
Optimization of the Efficiency of Stall Control Using Air Injection for Centrifugal Compressors
Authors: Halawa Taher , Gadala Mohamed S. , Alqaradawi Mohamed , Badr Osama
Published: November 2014

Numerical investigation of the optimization of the stall control efficiency for a high speed centrifugal compressor using air injection is presented. External air was injected close to the diffuser entrance at the shroud surface of the vaneless region. Injection was applied with mass flow rates of 0.7%, 1%, and 1.5% of the design inlet mass flow rate with six different angles of 0 deg, 10 deg, 20 deg, 30 deg, 40 deg, and 180 deg measured from the positive tangential direction at the vaneless region. Detailed comparisons were made between the case without using air injection and the different air injection cases by comparing velocity, pressure, and force fluctuations with time. Results showed that as the injection mass flow rate increases, the number of diffuser passages with reversed flow decreases for all cases of injection except for the case of reverse tangent injection. Results indicated that using angle of injection of 30 deg minimized the stall area and provided the least force fluctuations with no reversed flow compared to other injection angles. Finally, it was found that injecting air with mass flow rate of 1.5% of the inlet mass flow rate at an angle of 30 deg resulted in shifting of stall onset to a mass flow rate corresponding to 3.8 kg/s instead of 4 kg/s for a compressor without using air injection control.
Correspondence Between “Stable” Flame Macrostructure and Thermo-acoustic Instability in Premixed Swirl-Stabilized Turbulent Combustion
Authors: Taamallah Soufien , LaBry Zachary A. , Shanbhogue Santosh J. , Habib Mohamed A. M. , Ghoniem Ahmed F.
Published: November 2014

In this paper, we conduct an experimental investigation to study the link between the flame macroscale structure—or flame brush spatial distribution—and thermo-acoustic instabilities, in a premixed swirl-stabilized dump combustor. We operate the combustor with premixed methane–air in the range of equivalence ratio (φ) from the lean blowout limit to φ=0.75. First, we observe the different dynamic modes in this lean range as φ is raised. We also document the effect of φ on the flame macrostructure. Next, we examine the correspondence between dynamic mode transitions and changes in flame macrostructure. To do so, we modify the combustor length—by downstream truncation—without changing the underlying flow upstream. Thus, the resonant frequencies of the geometry are altered allowing for decoupling the heat release rate fluctuations and the acoustic feedback. Mean flame configurations in the modified combustor and for the same range of equivalence ratio are examined, following the same experimental protocol. It is found that not only the same sequence of flame macrostructures is observed in both combustors but also that the transitions occur at a similar set of equivalence ratio. In particular, the appearance of the flame in the outside recirculation zone (ORZ) in the long combustor—which occurs simultaneously with the onset of instability at the fundamental frequency—happens at similar φ when compared to the short combustor, but without being in latter case accompanied by a transition to thermo-acoustic instability. Then, we interrogate the flow field by analyzing the streamlines, mean, and rms velocities for the nonreacting flow and the different flame types. Finally, we focus on the transition of the flame to the ORZ in the acoustically decoupled case. Our analysis of this transition shows that it occurs gradually with an intermittent appearance of a flame in the ORZ and an increasing probability with φ. The spectral analysis of this phenomenon—we refer to as “ORZ flame flickering”—shows the presence of unsteady events occurring at two distinct low frequency ranges. A broad band at very low frequency in the range ∼(1 Hz–10 Hz) associated with the expansion and contraction of the inner recirculation zone (IRZ) and a narrow band centered around 28 Hz which is the frequency of rotation of the flame as it is advected by the ORZ flow.
Biomechanics and Mechanobiology of Trabecular Bone: A Review
Authors: Oftadeh Ramin , Perez-Viloria Miguel , Villa-Camacho Juan C. , Vaziri Ashkan , Nazarian Ara
Published: November 2014

Trabecular bone is a highly porous, heterogeneous, and anisotropic material which can be found at the epiphyses of long bones and in the vertebral bodies. Studying the mechanical properties of trabecular bone is important, since trabecular bone is the main load bearing bone in vertebral bodies and also transfers the load from joints to the compact bone of the cortex of long bones. This review article highlights the high dependency of the mechanical properties of trabecular bone on species, age, anatomic site, loading direction, and size of the sample under consideration. In recent years, high resolution micro finite element methods have been extensively used to specifically address the mechanical properties of the trabecular bone and provide unique tools to interpret and model the mechanical testing experiments. The aims of the current work are to first review the mechanobiology of trabecular bone and then present classical and new approaches for modeling and analyzing the trabecular bone microstructure and macrostructure and corresponding mechanical properties such as elastic properties and strength.
Directional Tortuosity as a Predictor of Modulus Damage for Vertebral Cancellous Bone
Authors: Fyhrie David P. , Zauel Roger
Published: November 2014

There are many methods used to estimate the undamaged effective (apparent) moduli of cancellous bone as a function of bone volume fraction (BV/TV), mean intercept length (MIL), and other image based average microstructural measures. The MIL and BV/TV are both only functions of the cancellous microstructure and, therefore, cannot directly account for damage induced changes in the intrinsic trabecular hard tissue mechanical properties. Using a nonlinear finite element (FE) approximation for the degradation of effective modulus as a function of applied effective compressive strain, we demonstrate that a measurement of the directional tortuosity of undamaged trabecular hard tissue strongly predicts directional effective modulus (r2 > 0.90) and directional effective modulus degradation (r2 > 0.65). This novel measure of cancellous bone directional tortuosity has the potential for development into an anisotropic approach for calculating effective mechanical properties as a function of trabecular level material damage applicable to understanding how tissue microstructure and intrinsic hard tissue moduli interact to determine cancellous bone quality.
The Effect of Rate Dependence on Localization of Deformation and Failure in Softening Solids
Authors: Needleman Alan
Published: November 2014

Localization of deformation and failure, a complete loss of stress carrying capacity, is studied for two rate dependent constitutive relations: (i) a Kelvin–Voigt solid and (ii) a viscoplastic solid. A planar block infinite in one direction is subjected to monotonically increasing shear displacements at a fixed rate. Geometry changes are neglected and attention is confined to quasi-static loading conditions. For the Kelvin–Voigt solid, localization precedes failure if there is hardening outside the band and softening inside the band while failure precedes localization if there is softening both inside and outside the band. For the viscoplastic solid, localization precedes failure when there is softening inside the band regardless of the sign of the hardening parameter outside band. For the Kelvin–Voigt solid, it is found that the localization time (or strain) varies logarithmically with the band thickness for small values of band thickness while the time (or strain) to a complete loss of stress carrying capacity has, in general, a different scaling with band thickness. For the viscoplastic solid, with plastic dissipation outside the band as well as inside the band, the strain and the total plastic dissipation to failure are nearly independent of band thickness for sufficiently small thickness values, with what is sufficiently small decreasing with decreasing rate sensitivity. Possible implications for grid based modeling of localization and failure are discussed.
Finite Element Modeling of Blast Lung Injury in Sheep
Authors: Gibbons Melissa M. , Dang Xinglai , Adkins Mark , Powell Brian , Chan Philemon
Published: November 2014

A detailed 3D finite element model (FEM) of the sheep thorax was developed to predict heterogeneous and volumetric lung injury due to blast. A shared node mesh of the sheep thorax was constructed from a computed tomography (CT) scan of a sheep cadaver, and while most material properties were taken from literature, an elastic–plastic material model was used for the ribs based on three-point bending experiments performed on sheep rib specimens. Anesthetized sheep were blasted in an enclosure, and blast overpressure data were collected using the blast test device (BTD), while surface lung injury was quantified during necropsy. Matching blasts were simulated using the sheep thorax FEM. Surface lung injury in the FEM was matched to pathology reports by setting a threshold value of the scalar output termed the strain product (maximum value of the dot product of strain and strain-rate vectors over all simulation time) in the surface elements. Volumetric lung injury was quantified by applying the threshold value to all elements in the model lungs, and a correlation was found between predicted volumetric injury and measured postblast lung weights. All predictions are made for the left and right lungs separately. This work represents a significant step toward the prediction of localized and heterogeneous blast lung injury, as well as volumetric injury, which was not recorded during field testing for sheep.
Effects of Cryopreservation on the Depth-Dependent Elastic Modulus in Articular Cartilage and Implications for Osteochondral Grafting
Authors: Kahn David , Les Clifford , Xia Yang
Published: November 2014

Cryopreservation of articular cartilage is often used in storage of experimental samples and osteochondral grafts, but the depth-dependence and concentration of glycosaminoglycan (GAG) are significantly altered when cryogenically stored without a cryoprotectant, which will reduce cartilage stiffness and affect osteochondral graft function and long-term viability. This study investigates our ability to detect changes due to cryopreservation in the depth-dependent elastic modulus of osteochondral samples. Using a direct-visualization method requiring minimal histological alterations, unconfined stepwise stress relaxation tests were performed on four fresh (never frozen) and three cryopreserved (−20 °C) canine humeral head osteochondral slices 125 ± 5 μm thick. Applied force was measured and tissue images were taken at the end of each relaxation phase using a 4× objective. Intratissue displacements were calculated by tracking chondrocytes through consecutive images for various intratissue depths. The depth-dependent elastic modulus was compared between fresh and cryopreserved tissue for same-depth ranges using analysis of variance (ANOVA) with Tukey post-test with a 95% confidence interval. Cryopreservation was found to significantly alter the force–displacement profile and reduce the depth-dependent modulus of articular cartilage. Excessive collagen fiber folding occurred at 40–60% relative depth, producing a “black line” in cryopreserved tissue. Force–displacement curves exhibited elongated toe-region in cryopreserved tissue while fresh tissue had nonmeasurable toe-region. Statistical analysis showed significant reduction in the elastic modulus and GAG concentration throughout the tissue between same-depth ranges. This method of cryopreservation significantly reduces the depth-dependent modulus of canine humeral osteochondral samples.
Methodology for Assessment of Surface Defects in Undermatched Pipeline Girth Welds
Authors: Pépin Aurélien , Tkaczyk Tomasz , O'Dowd Noel , Nikbin Kamran
Published: November 2014

The demand for subsea transport of highly corrosive constituents has noticeably increased in recent years. This has driven the requirement for high strength pipelines with enhanced corrosion resistance such as chromium stainless steel or bimetal pipes. The latter are carbon steel pipes with a corrosion resistant alloy lining. Reeling is a cost effective installation method for small to medium size subsea pipelines, up to 457.2 mm (18 in.) in diameter. However, plastic straining associated with reeling has an effect on weld defect acceptance criteria. The maximum acceptable defect sizes are typically developed using engineering critical assessment (ECA), based on the reference stress method, which requires that the weld metal is equal to or stronger than the parent metal in terms of the stress–strain curve. However, evenmatch/overmatch cannot always be achieved in the case of subsea stainless or bimetal pipelines. In this work, a parametric finite-element (FE) study was performed to assess the effect of weld metal undermatch on the crack driving force, expressed in terms of the crack tip opening displacement (CTOD). Subsequently, the fracture assessment methodology for reeled pipes was proposed, where the ECA as per BS7910 is first carried out. These acceptable defect sizes are then reduced, using an analytical formula developed in this work, to account for weld undermatch.
High-Precision Cutting Tool Tracking With a Magnetic Bearing Spindle
Authors: Smirnov Alexander , Pesch Alexander H. , Pyrhönen Olli , Sawicki Jerzy T.
Published: November 2014

A method is presented for tool tracking in active magnetic bearing (AMB) spindle applications. The method uses control of the AMB air gap to achieve the desired tool position. The reference tracking problem is transformed from the tool coordinates into the AMB control axes by bearing deflection optimization. Therefore, tool tracking can be achieved by an off-the-shelf AMB controller. The method is demonstrated on a high-speed AMB boring spindle with a proportional integral derivative (PID) control. The hypothetical part geometries are traced in the range of 30 μm. Static external loading is applied to the tool to confirm disturbance rejection. Finally, a numerical simulation is performed to verify the ability to control the tool during high-speed machining.
Photonic microstructures in lithium niobate by potassium hydroxide-assisted ion beam-enhanced etching
Authors: Geiss Reinhard , Brandt Juliane , Hartung Holger , Tünnermann Andreas , Pertsch Thomas , Kley Ernst-Bernhard , Schrempel Frank
Published: November 2014

Lithium niobate is treated with argon ion beam irradiation of varying energy, resulting in a homogeneously damaged surface layer. This layer is subsequently etched with potassium hydroxide (KOH), and etch rates are recorded for different experimental conditions such as varying temperature and concentration of the water-based KOH solution. The dependence of the etch rate upon the normalized fluence of the ion irradiation shows good selectivity, which makes the effect useful for nano- and microfabrication. Ultimately, photonic crystals and gratings are fabricated by KOH-assisted ion beam-enhanced etching to prove the potential of this method for applications in functional nano- and micro-optics.
TiO2 nanotube arrays for photocatalysis: Effects of crystallinity, local order, and electronic structure
Authors: Liu Jing , Hosseinpour Pegah M. , Luo Si , Heiman Don , Menon Latika , Arena Dario A. , Lewis Laura H.
Published: November 2014

To furnish insight into correlations of electronic and local structure and photoactivity, arrays of short and long TiO2 nanotubes were synthesized by electrochemical anodization of Ti foil, followed by thermal treatment in O2 (oxidizing), Ar (inert), and H2 (reducing) environments. The physical and electronic structures of these nanotubes were probed with x-ray diffraction, scanning electron microscopy, and synchrotron-based x-ray absorption spectroscopy, and correlated with their photocatalytic properties. The photocatalytic activity of the nanotubes was evaluated by monitoring the degradation of methyl orange under UV-VIS light irradiation. Results show that upon annealing at 350 °C all as-anodized amorphous TiO2 nanotube samples partially transform to the anatase structure, with variations in the degree of crystallinity and in the concentration of local defects near the nanotubes' surface (∼5 nm) depending on the annealing conditions. Degradation of methyl orange was not detectable for the as-anodized TiO2 nanotubes regardless of their length. However, the annealed long nanotubes demonstrated detectable catalytic activity, which was more significant with the H2-annealed nanotubes than with the Ar- and O2-annealed nanotube samples. This enhanced photocatalytic response of the H2-annealed long nanotubes relative to the other samples is positively correlated with the presence of a larger concentration of lattice defects (such as Ti3+ and anticipated oxygen vacancies) and a slightly lower degree of crystallinity near the nanotube surface. These physical and electronic structural attributes impact the efficacy of visible light absorption; moreover, the increased concentration of surface defects is postulated to promote the generation of hydroxyl radicals and thus accelerate the photodegradation of the methyl orange. The information obtained from this study provides unique insight into the role of the near-surface electronic and defect structure, crystal structure, and the local chemical environment on the photocatalytic activity and may be employed for tailoring the materials' properties for photocatalysis and other energy-related applications.