bluuebunny/crossref_metadata_2025 huggingface dataset:
Pyroelectric and Dielectric Properties of Mn Modified 0.82Bi0.5Na0.5TiO3–0.18Bi0.5K0.5TiO3 Lead‐Free Thick Films
Authors: Zhang Haibo , Jiang Shenglin , Kajiyoshi Koji
Published: June 2009

MnO‐doped 0.82Bi0.5Na0.5TiO3–0.18Bi0.5K0.5TiO3(NBT–KBT) thick films with thickness about 40 μm have been prepared using screen printing on Pt electroded alumina substrates. The strong pyroelectric coefficient of 3.8 × 10−4 C·(m2·°C)–1 was observed in 1.0 mol% MnO‐doped‐thick films, and the calculated detectivity figure of merit as high as 1.1 × 10−5 Pa−0.5, which can be comparable to that of the commonly used lead based materials. The enhancement of the pyroelectric performances is attributed to the reductions in dielectric constant and loss and the improvements in the pyroelectric coefficient, which can be ascribed to the Mn acts as a hard dopant in the NBT–KBT lattice, creating oxygen vacancies and pinning the residual domains.
Fabrication of Ceramics with Complex Porous Structures by the Impregnate–Freeze‐Casting Process
Authors: Han Jiecai , Hu Luyang , Zhang Yumin , Zhou Yufeng
Published: June 2009

The ceramics with complex porous structures were fabricated by a combination of impregnating and freeze‐casting process. The polyurethane sponge was impregnated in the mold with 20 vol% of aqueous alumina slurry, and then the bottom of the cast body was kept at a constant cooling rate of 6°C/min to induce unidirectional solidification. After drying and sintering of the green part, porous ceramic with obvious lamellar architectures was prepared. The lamellae thickness and interlayer distance were as large as ∼9 and ∼15 μm, respectively. The large pores, which resulted from the burn‐up of sponge struts were homogeneously distributed in the sample. The use of the porous template introduced some local interruption of the lamellar structures. However, high compression strength for the porous ceramic can still be obtained.
M‐Doped Al2TiO5 (M=Cr, Mn, Co) Solid Solutions and their Use as Ceramic Pigments
Authors: Dondi Michele , Lyubenova Teodora Stoyanova , Carda Juan B. , Ocaña Manuel
Published: June 2009

New ceramic pigments based on the tialite (Al2TiO5) structure, doped with Co (pink), Cr (green), or Mn (brown), were prepared through the pyrolysis of aerosols followed by calcination of the obtained powders at 1400°C. The expected decomposition of Al2TiO5 into a mixture of Al2O3 and TiO2 on refiring was inhibited by Cr‐doping and also by co‐doping with Mg the Mn‐ or Co‐doped samples. Microstructure and phase evolution during pigment preparation were monitored by scanning electron microscopy and XRPD. Unit cell parameters of tialite were determined by Rietveld refinement of the X‐ray diffraction patterns, revealing in all cases the formation of solid solutions where the solubility of dopants in the Al2TiO5 lattice followed the trend Co<Mn<Cr. The valence state and possible location of dopants in the tialite lattice were investigated by X‐ray photoelectron spectra and diffuse reflectance spectroscopies, which suggested the presence of Cr3+ ions in a large interstitial site of the tialite lattice with a distorted octahedral geometry, and of Mn3+ and Co2+ ions in the Al3+ octahedral sites of the tialite lattice in the former case, and in both Al3+ and Ti4+ octahedral sites in the latter. Testing the ceramic glazes assessed the technological behavior of pigments, which found that the color stability was reasonably good for the Mn‐doped tialite and the Cr‐doped pigment, although the latter suffered a small loss of green hue. The Co‐doped pigment was found to be not stable in glazes, undergoing a cobalt‐leaching effect.
High Tc in Electrospun BaTiO3 Nanofibers
Authors: Li Heping , Wu Hui , Lin Dandan , Pan Wei
Published: June 2009

BaTiO3 nanofibers were prepared by electrospinning. The morphology of synthesized BaTiO3 nanofibers was investigated under different heat treatment conditions. The phase transformations in BaTiO3 nanofibers were monitored using Raman spectroscopy. It has been found that the Curie temperature of BaTiO3 nanofibers increased to 220°C, which is notably higher than the bulk BaTiO3 ceramics.
Retinoids regulate human amniotic tissue‐type plasminogen activator gene by a two‐step mechanism
Authors: Borel Valerie , Marceau Geoffroy , Gallot Denis , Blanchon Loïc , Sapin Vincent
Published: June 2009

The collagenolytic effects of the tissue‐type plasminogen activator (t‐PA) leading to extracellular matrix degradation are clearly involved in the physiopathology of human foetal membranes rupture. Nevertheless, the regulation of t‐PA gene expression in extraembryonic developmental contexts remains unknown. The aim of our study is to propose the retinoic acids (RAs) as molecular regulators of t‐PA expression in foetal membranes. RA induced t‐PA mRNA and proteins in a time‐dependent manner in amniotic membrane explants and Wistar Institute Susan Hayflick (WISH) cells. Furthermore, the use of cycloheximide revealed a two‐step regulation of t‐PA gene. Gene reporter assays confirmed that the RA‐induced t‐PA gene expression occurred through interactions of retinoid receptors (RARs and RXRs) with a DR5 response element located at –7 kb from the transcription site. Site‐directed mutagenesis of this region of the t‐PA promoter showed that SP1 factor was also retinoid‐mediated induction, and immunoprecipitation assays revealed that SP1 and RAR/RXR interacted physically. Chromatin immunoprecipitation demonstrated that interactions between RARs, RXRs and t‐PA promoter were time dependent: RAR‐α/RXR‐α bound DR5 motif before and up to 12 hrs of RA exposure, and RAR‐β/RXR‐α bound DR5 response element after 12 hrs of RA treatment. Finally, experiments using shRNA and RAR‐β‐specific antagonist revealed that reducing RAR‐β induction decreased t‐PA induction. Altogether, our results established that the RA‐mediated regulation of t‐PA in human foetal membranes occurred through two steps, with a major role played by RAR‐β.
Immune cells and angiogenesis
Authors: Ribatti Domenico , Crivellato Enrico
Published: June 2009

Introduction

The importance of angiogenesis in physiological and pathological conditions

The contribution of immune cells to angiogenesis in inflammation and tumour growth

Neutrophils

Basophils

Eosinophils

Monocytes‐macrophages

Lymphocytes

Dendritic cells

The contribution of progenitor cells and adult cell transdifferentiation

Mast cells

Platelets

Conclusions

Both innate and adaptive immune cells are involved in the mechanisms of endothelial cell proliferation, migration and activation, through the production and release of a large spectrum of pro‐angiogenic mediators. These may create the specific microenvironment that favours an increased rate of tissue vascularization. In this review, we will focus on the immune cell component of the angiogenic process in inflammation and tumour growth. As angiogenesis is the result of a net balance between the activities exerted by positive and negative regulators, we will also provide information on some antiangiogenic properties of immune cells that may be utilized for a potential pharmacological use as antiangiogenic agents in inflammation as well as in cancer.
PPARδ promotes wound healing by up‐regulating TGF‐β1‐dependent or ‐independent expression of extracellular matrix proteins
Authors: Ham Sun Ah , Kim Hyo Jung , Kim Hyun Joon , Kang Eun Sil , Eun So Young , Kim Gil Hyeong , Park Myung Hyun , Woo Im Sun , Kim Hye Jung , Chang Ki Churl , Lee Jae Heun , Seo Han Geuk
Published: June 2009

Although the peroxisome proliferator‐activated receptor (PPAR) δ has been implicated in the wound healing process, its exact role and mechanism of action have not been fully elucidated. Our previous findings showed that PPARδ induces the expression of the transforming growth factor (TGF)‐β1, which has been implicated in the deposit of extracellular matrix proteins. Here, we demonstrate that administration of GW501516, a specific PPARδ ligand, significantly promoted wound closure in the experimental mouse and had a profound effect on the expression of collagen types I and III, alpha‐smooth muscle actin, pSmad3 and TGF‐β1, which play a pivotal role in wound healing processes. Activation of PPARδ increased migration of human epidermal keratinocytes and dermal fibroblasts in in vitro scrape‐wounding assays. Addition of a specific ALK5 receptor inhibitor SB431542 significantly suppressed GW501516‐induced migration of human keratinocytes and fibroblasts. In these cells, activated PPARδ also induced the expression of collagen types I and III and fibronectin in a TGF‐β1‐dependent or ‐independent manner. The effect of PPARδ on the expression of type III collagen was dually regulated by the direct binding of PPARδ and Smad3 to a direct repeat‐1 site and a Smad‐binding element, respectively, of the type III gene promoter. Taken together, these results demonstrated that PPARδ plays an important role in skin wound healing in vivo and that it functions by accelerating extracellular matrix‐mediated cellular interactions in a process mediated by the TGF‐β1/Smad3 signaling‐dependent or ‐ independent pathway.
Reduction of circulating soluble Flt‐1 alleviates preeclampsia‐like symptoms in a mouse model
Authors: Bergmann Astrid , Ahmad Shakil , Cudmore Melissa , Gruber Achim D. , Wittschen Petra , Lindenmaier Werner , Christofori Gerhard , Gross Volkmar , Gonzalves Andrey Ch. da Costa , Gröne Hermann‐Josef , Ahmed Asif , Weich Herbert A.
Published: June 2009

Preeclampsia (PE) is characterized by widespread endothelial damage with hypertension, proteinuria, glomeruloendotheliosis and elevated soluble Flt‐1 (sFlt‐1), a natural occurring antagonist of vascular endothelial growth factor (VEGF). Cancer patients receiving anti‐VEGF therapy exhibit similar symptoms. We suggested that a decrease in circulating sFlt‐1 would alleviate the symptoms associated with PE. Adenoviral (Adv) overexpression of sFlt‐1 induced proteinuria, caused glomerular damage and increase in blood pressure in female Balb/c mice. Circulating level of sFlt‐1 above 50 ng/ml plasma induced severe vascular damage and glomerular endotheliosis. Albumin concentration in urine was elevated up to 30‐fold, compared to control AdvGFP‐treated animals. The threshold of kidney damage was in the range of 20–30 ng/ml sFlt‐1 in plasma (8–15 ng/ml in urine). Co‐administration of AdvsFlt‐1 with AdvVEGF to neutralize circulating sFlt‐1 resulted in more than a 70% reduction in free sFlt‐1 in plasma, more than 80% reduction in urine and rescued the damaging effect of sFlt‐1 on the kidneys. This demonstrates that below a critical threshold sFlt‐1 fails to elicit damage to the fenestrated endothelium and that co‐expression of VEGF is able to rescue effects mediated by sFlt‐1 overexpression.
MFTZ‐1 reduces constitutive and inducible HIF‐1α accumulation and VEGF secretion independent of its topoisomerase II inhibition
Authors: Dai Mei , Miao Ze‐Hong , Ren Xuan , Tong Lin‐Jiang , Yang Na , Li Ting , Lin Li‐Ping , Shen Yue‐Mao , Ding Jian
Published: June 2009

The macrolide compound MFTZ‐1 has been identified as a novel topoisomerase II (Top2) inhibitor with potent in vitro and in vivo anti‐tumour activities. In this study, we further examined the effects of MFTZ‐1 on hypoxia‐inducible factor‐1α (HIF‐1α) accumulation, vascular endothelial growth factor (VEGF) secretion and angiogenesis. MFTZ‐1 reduced HIF‐1α accumulation driven by hypoxia or growth factors in human cancer cells. Mechanistic studies revealed that MFTZ‐1 did not affect the degradation of HIF‐1α protein or the level of HIF‐1α mRNA. By contrast, MFTZ‐1 apparently inhibited constitutive and inducible activation of both phosphatidylinositol‐3‐kinase (PI3K)‐Akt and p42/p44 mitogen‐activated protein kinase (MAPK) pathways. Further studies revealed that MFTZ‐1 abrogated the HIF‐1α‐driven increase in VEGF mRNA and protein secretion. MFTZ‐1 also lowered the basal level of VEGF secretion. The results reveal an important feature that MFTZ‐1 can reduce constitutive, HIF‐1α‐independent VEGF secretion and concurrently antagonize inducible, HIF‐1α‐dependent VEGF secretion. Moreover, MFTZ‐1 disrupted tube formation of human umbilical vein endothelial cells (HUVECs) stimulated by hypoxia with low‐concentration serum or by serum at normoxia, and inhibited HUVECs migration at normoxia. MFTZ‐1 also prevented microvessel outgrowth from rat aortic ring. These data reflect the potent anti‐angiogenesis of MFTZ‐1 under different conditions. Furthermore, using specific small interfering RNA targeting Top2α or Top2‐defective HL60/MX2 cells, we showed that MFTZ‐1 affected HIF‐1α accumulation and HUVECs tube formation irrelevant to its Top2 inhibition. Taken together, our data collectively reveal that MFTZ‐1 reduces constitutive and inducible HIF‐1α accumulation and VEGF secretion possibly via PI3K‐Akt and MAPK pathways, eliciting anti‐angiogenesis independently of its Top2 inhibition.
The contact allergen nickel sensitizes primary human endothelial cells and keratinocytes to TRAIL‐mediated apoptosis
Authors: Schmidt Marc , Hupe Mike , Endres Nicole , Raghavan Badrinarayanan , Kavuri Shyam , Geserick Peter , Goebeler Matthias , Leverkus Martin
Published: June 2009

Primary endothelial cells are fully resistant to TNF‐related apoptosis‐inducing ligand (TRAIL)‐mediated apoptosis. Here, we demonstrate that certain environmental conditions, such as exposure to the widespread allergen nickel, can dramatically increase the susceptibility of naturally resistant primary endothelial cells or keratinocytes to TRAIL‐induced apoptosis. While nickel treatment increased surface expression of the apoptosis‐inducing TRAIL receptors TRAIL‐R1 and TRAIL‐R2, it also up‐regulated the apoptosis‐deficient TRAIL‐R4, suggesting that modulation of TRAIL receptor expression alone is unlikely to fully account for the dramatic sensitization effect of nickel. Further analysis of candidate mediators revealed that nickel strongly repressed c‐FLIP at mRNA and protein levels. Accordingly, increased activation of Caspase‐8 and Caspase‐3 following nickel treatment was observed. Importantly, depletion of c‐FLIP by RNA interference could largely recapitulate the effect of nickel and sensitize endothelial cells to TRAIL‐dependent apoptosis in the absence of nickel pre‐treatment. Conversely, ectopic expression of c‐FLIPL largely protected nickel‐treated cells from TRAIL‐mediated apoptosis. Our data demonstrate that one key mechanism of sensitization of primary human endothelial cells or keratinocytes is transcriptional down‐regulation of c‐FLIP. We hypothesize that environmental factors, exemplified by the contact allergen nickel, strongly modulate death ligand sensitivity of endothelial cells and keratinocytes thus influencing vascular and epidermal function and integrity under physiological and pathophysiological conditions.
Cutaneous metastases as the first clinical sign of metastatic gastric carcinoma
Authors: Frey Lidia , Vetter‐Kauczok Claudia , Gesierich Anja , Bröcker Eva‐B. , Ugurel Selma
Published: June 2009

Cutaneous metastases from gastric cancer are uncommon with a frequency of 7 % but can rarely be the presenting sign. A 54‐year‐old man complained of multiple pea‐sized scalp nodules which had been present for four months. Histology showed a metastatic adenocarcinoma. Initial evaluation revealed liver metastases and gastroscopy then identified a tumor involving the distal esophagus and gastric cardia that was diagnosed as a gastric tubular carcinoma. The patient had a good response to polychemotherapy. While gastric carcinoma generally metastasizes to the abdominal wall or lymph nodes, our patient showed an exceptional variant with distant cutaneous metastases as the first clinical sign.
Localization and Dynamic Change of Saponin in Vegetative Organs of Polygala tenuifolia
Authors: Teng Hong‐Mei , Fang Min‐Feng , Cai Xia , Hu Zheng‐Hai
Published: June 2009

Anatomical, histochemical and phytochemical methods were used to investigate the structure, localization and dynamic changes of total saponin and senegenin of vegetative organs in Polygala tenuifolia Willd. Histochemical localization results showed that saponin accumulated mainly in parenchyma cells of vegetative organs. The phytochemical results also showed that the saponin accumulated in the vegetative organs of P. tenuifolia, with higher content in roots and lower content in the aerial parts that included stems and leaves. The saponin content and dry weight of the vegetative organs of P. tenuifolia had dynamic variance at the developmental stages and all reached the highest level in the post‐fruit period. Hence, the roots and aerial parts should be gathered in August to make full use of the plant. As the root is the main medicinal organ of P. tenuifolia, the content of total saponin and senegenin of different aged and different parts of the root were determined. The content of total saponin and senegenin exhibited a sustained decreasing trend with increasing root age; therefore, the annual roots had high quality. The content of total saponin and senegenin in different parts of the root showed obvious variation. The content in the “skin areas” was much higher than that of xylem. The results offer a theoretical basis for determining the appropriate harvesting stage and a reasonable harvest of P. tenuifolia.
Jasmonic Acid is Induced in a Biphasic Manner in Response of Pea Seedlings to Wounding
Authors: Yang Hao‐Ru , Tang Ke , Liu Hong‐Tao , Pan Qiu‐Hong , Huang Wei‐Dong
Published: June 2009

The role of jasmonic acid (JA) in plant wounding response has been demonstrated. However, the source of JA in wound signaling remains unclear. In the present study, pea seedlings were used as material to investigate the systemic induction of JA and the activation of lipoxygenase (LOX)‐dependent octadecanoid pathway upon wounding. The results showed that endogenous JA could induce two peaks in the wounded leaves and the stalks, while only one peak in the systemic leaves. LOX activity and its protein amount were also induced and the stimulation mainly occurred in the late phase, while one peak of induction was present after pretreatment with JA. Applied nordihydroguaiaretic acid (NDGA), an inhibitor of LOX activity, only inhibited the induction of JA in the late phase, and the resistance of pea was impaired. Furthermore, 13(S)‐hydroperoxy‐9(Z), 11(E)‐octadecadienoic acid (13(S)‐H(P)ODE) was confirmed to be the main product of LOX throughout the experimental time. In addition, immunocytochemical analysis also revealed the occurrence of JA biosynthesis and transport upon wounding. These results demonstrated that wound‐induced JA in wounded leaves resulted from its biosynthesis and conversion from its conjugates, while in systemic leaves resulted from its transport and biosynthesis; and proved that the LOX pathway was vital to the wound‐induced defense response involved in JA biosynthesis.
DRYING OF CHILI PEPPER (CAPSCIUM FRUTSCENS)
Authors: TUNDE‐AKINTUNDE T.Y. , AFOLABI T.J.
Published: June 2009

Drying is one of the common methods of food preservation and is carried out on untreated/unblanched and treated/blanched chili pepper using sun, solar and hot‐air drying. The drying curves generated from the three methods showed that drying of treated/blanched pepper was faster than that of untreated/unblanched pepper. The drying rate period observed for all the methods and samples was the falling rate drying regime. This suggests that the blanching pretreatment assisted water loss and thus decreased the resistance to water loss at the surface of the product. The drying time of the dried pepper varied from 27 h for hot‐air drying to 144.5 h for sun drying respectively. The values of moisture diffusivity coefficient ranged from 2.163 × 10−9 m2/s for hot‐air drying to 1.125 × 10−9 m2/s for sun drying.

PRACTICAL APPLICATIONS

A common method of preserving pepper, a vegetable with versatile use, is drying and this is done by sun, solar and oven‐drying methods. Climatic variations of sun and solar drying make it unsuitable for large‐scale production. Hot‐air drying is thus considered as an alternative drying method because it decreases drying time and improves the hygienic quality of the dried product. Pretreating pepper by blanching increases its rate of drying. The effect of each drying method on the drying rate, equilibrium moisture content and moisture diffusivity coefficient were used to compare the drying methods. Hot‐air drying had the lowest drying time whereas pretreated samples also dried faster. The effective moisture diffusivity of oven dried samples as well as pretreated samples were highest. This indicates that oven drying reduces drying time and can be used to dry pepper samples for large‐scale production.
ISOLATION OF CAFFEINE FROM TEA WASTE USING SUBCRITICAL WATER EXTRACTION
Authors: SHALMASHI ANVAR , ABEDI MOHAMMAD , GOLMOHAMMAD FERESHTEH , EIKANI MOHAMMAD HASSAN
Published: June 2009

The aim of this study was to investigate the isolation of caffeine from tea waste using subcritical water extraction (SCWE) method. The effect of various operating conditions such as water temperature (100,125,150, 175 and 200C), water flow rate (1, 2 and 4 g/min), mean particle size (0.25, 0.5, 1 and 2 mm) and pressure (20, 30 and 40 bar) on extraction yield and rate were determined. SCWE at 175C, water flow rate of 4 g/min and mean particle size of 0.5 mm was found to be able to recover 0.77% (w/w) of caffeine present in the tea waste within 1.5 h of extraction. In comparison with the SCWE, conventional hot water extraction showed 0.46% (w/w) extraction yield. It was found also that pressure had no effect on extraction yield and rate. A sustainable and environmentally friendly procedure has been used for the Fourier transform infrared determination of caffeine in tea waste extracted samples.

PRACTICAL APPLICATIONS

Subcritical water extraction (SCWE), as a green solvent, can be used in many different fields of applications. It can be used to extract antioxidant compounds from rosemary plants as well as to extract whitening agents and azo dyes in samples. Additionally, soil can be remediated through SCWE of dioxins. Recently, subcritical water has become of great interest as an alternative solvent for extraction of natural active compounds. In recent years, extraction of flavors, fragrances and antioxidant components from plant materials, and hydrolysis of carbohydrates, vegetable oils and fatty acids have been widely investigated by many researchers. Using subcritical water as a reaction media are some other interesting fields for practical applications.
EFFECT OF SURIMI CONTAINING SPENT LAYING HEN BREAST ON THE QUALITY OF CRAB ANALOGUE
Authors: JIN S.K. , KIM I.S. , CHOI Y.J. , KIM B.G. , HUR S.J.
Published: June 2009

The crab analogue samples were made from Alaska pollack with golden threadfin bream surimi (Control), and a combination of Alaska pollack with golden threadfin bream surimi and a low amount of spent hen breast surimi (treatment 1, T1). Treatment 2 (T2) was made from Alaska pollack with golden threadfin bream surimi and a high amount of spent hen breast surimi, and treatment 3 (T3) was made from Alaska pollack with golden threadfin bream with mechanically deboned chicken meat (MDCM). T3 shows a significantly lower moisture amount compared with other samples. Crude protein was higher in T1 than in other samples at 4 weeks of storage. pH was significantly lower in control (C) than those of other samples until 2 weeks of storage, and cooking loss was higher in C than in other samples, while shear force and cholesterol were higher in T3 compared with other samples. In meat color, lightness (L*) was significantly higher in T2 than in other samples. Whiteness of T2 was significantly higher compared with that of other samples. In fatty acid composition, saturated fatty acid was significantly higher in T3, while unsaturated fatty acid was higher in C than in other samples. C showed significantly higher thiobarbituric acid‐reactive substances (TBARS) value, while TBARS value was lower in T2 compared with other samples. In sensory evaluation, the color and overall acceptability were significantly lower in T3 compared with other samples. These results demonstrated that the crab analogue product could be made from spent hen breast, although the quality of crab analogue containing MDCM sample (T3) is a little lower than other crab analogue samples.

PRACTICAL APPLICATIONS

The application of the surimi technology in the production of a surimi‐based product from other meats such as chicken, pork and beef could provide a new approach toward increasing its value and utilization. In the present study, imitation crab analogue was made from surimi containing spent laying hen breast with various ingredients. Imitation crab analogue product can be made from spent laying hen breast, although the quality of imitation crab analogue containing mechanically deboned chicken meat is a little lower than that of other imitation crab analogue samples.
Identification and Characterization of Kava‐derived Compounds Mediating TNF‐α Suppression
Authors: Pollastri Michael P. , Whitty Adrian , Merrill Jamie Cassidy , Tang Xiaoren , Ashton Trent D. , Amar Salomon
Published: June 2009

There is a substantial unmet need for new classes of drugs that block TNF‐α‐mediated inflammation, and particularly for small molecule agents that can be taken orally. We have screened a library of natural products against an assay measuring TNF‐α secretion in lipopolysaccharide‐stimulated THP‐1 cells, seeking compounds capable of interfering with the TNF‐α‐inducing transcription factor lipopolysaccharide‐induced TNF‐α factor. Among the active compounds were several produced by the kava plant (Piper mysticum), extracts of which have previously been linked to a range of therapeutic effects. When tested in vivo, a representative of these compounds, kavain, was found to render mice immune to lethal doses of lipopolysaccharide. Kavain displays promising pharmaceutical properties, including good solubility and high cell permeability, but pharmacokinetic experiments in mice showed relatively rapid clearance. A small set of kavain analogs was synthesized, resulting in compounds of similar or greater potency in vitro compared with kavain. Interestingly, a ring‐opened analog of kavain inhibited TNF‐α secretion in the cell‐based assay and suppressed lipopolysaccharide‐induced TNF‐α factor expression in the same cells, whereas the other compounds inhibited TNF‐α secretion without affecting lipopolysaccharide‐induced TNF‐α factor levels, indicating a potential divergence in mechanism of action.
seqphase: a web tool for interconverting phase input/output files and fasta sequence alignments
Authors: FLOT J‐F.
Published: June 2009

The program phase is widely used for Bayesian inference of haplotypes from diploid genotypes; however, manually creating phase input files from sequence alignments is an error‐prone and time‐consuming process, especially when dealing with numerous variable sites and/or individuals. Here, a web tool called seqphase is presented that generates phase input files from fasta sequence alignments and converts phase output files back into fasta. During the production of the phase input file, several consistency checks are performed on the dataset and suitable command line options to be used for the actual phase data analysis are suggested. seqphase was written in perl and is freely accessible over the Internet at the address http://www.mnhn.fr/jfflot/seqphase.
Misplaced Inventory and Radio‐Frequency Identification (RFID) Technology: Information and Coordination
Authors: Camdereli Almula Z. , Swaminathan Jayashankar M.
Published: June 2009

Misplaced inventory is a major operational problem in many supply chains. Radio‐frequency identification (RFID) technology has been publicized as a promising solution for the misplaced inventory. Adoption of this technology has a fixed cost and variable cost of implementation, which can cause incentive issues in the supply chain. In this paper, we consider a supply chain under misplacement of inventory subject to uncertain demand. We study both centralized and decentralized cases and identify the conditions to coordinate the supply chain under implementation of RFID. We show that the incentives of the parties for investing in the technology are not perfectly aligned in the existence of the fixed cost of investment. Based on the relative payments of the parties for the fixed cost of investment, the incentives to adopt RFID can be characterized into regions, where we observe only one party or two parties benefiting from the technology when the tag price falls in a region specified in the paper. We further establish the effects of changes in mean and variance of a uniform demand on the incentives for investing in RFID and find that the incentives of the firms may indeed decrease as demand becomes more variable.
Glycinergic input of widefield, displaced amacrine cells of the mouse retina
Authors: Majumdar Sriparna , Weiss Jan , Wässle Heinz
Published: June 2009

Glycine receptors (GlyRs) of displaced amacrine cells of the mouse retina were analysed using whole cell recordings and immunocytochemical staining with subunit‐specific antibodies. During the recordings the cells were filled with a fluorescent tracer and 11 different morphological types could be identified. The studies were performed in wild‐type mice and in mutant mice deficient in the GlyRα1 (Glra1spd‐ot, ‘oscillator’ mouse), the GlyRα2 (Glra2−/−) and the GlyRα3 subunit (Glra3−/−). Based on their responses to the application of exogenous glycine in the retinas of wild‐type and mutant mice, the cells were grouped into three major classes: group I cells (comprising the morphological types MA‐S5, MA‐S1, MA‐S1/S5, A17, PA‐S1, PA‐S5 and WA‐S1), group II cells (comprising the morphological types PA‐S4, WA‐S3 and WA‐multi) and ON‐starburst cells. For further analysis, spontaneous inhibitory postsynaptic currents (sIPSCs) were measured both in wild‐type and mutant mouse retinas. Glycinergic sIPSCs and glycine induced currents of group I cells remained unaltered across wild‐type and the three mutant mice (mean decay time constant of sIPSCs, τ∼25 ms). Group II cells showed glycinergic sIPSCs and glycine induced currents in wild‐type, Glra1spd‐ot and Glra3−/− mice (τ∼25 ms); however, glycinergic currents were absent in group II cells of Glra2−/− mice. Glycine induced currents and sIPSCs recorded from ON‐starburst amacrine cells did not differ significantly between wild‐type and the mutant mouse retinas (τ∼50–70 ms). We propose that GlyRs of group II cells are dominated by the α2 subunit; GlyRs of ON‐starburst amacrine cells appear to be dominated by the α4 subunit.
Long chain fatty acids and dietary fats in fetal nutrition
Authors: Cetin Irene , Alvino Gioia , Cardellicchio Manuela
Published: June 2009

Long chain polyunsaturated fatty acids are essential nutrients for a healthy diet. The different kinds consumed by the mother during gestation and lactation may influence pregnancy, fetal and also neonatal outcome. The amount of fatty acids transferred from mother to fetus depends not only on maternal metabolism but also on placental function, i.e. by the uptake, metabolism and then transfer of fatty acids to the fetus. The third trimester of gestation is characterized by an increase of long chain polyunsaturated fatty acids in the fetal circulation, in particular docosahexaenoic acid, especially to support brain growth and visual development. These mechanisms may be altered in pathological conditions, such as intrauterine growth restriction and diabetes, when maternal and fetal plasma levels of long chain polyunsaturated fatty acids undergo significant changes. The aim of this review is to describe the maternal and placental factors involved in determining fetal fatty acid availability and metabolism, focusing on the specific role of long chain polyunsaturated fatty acids in normal and pathological pregnancies.
Investigation Into Cavitation Erosion Pits
Authors: Abouel-Kasem A. , El-Deen A. Ezz , Emara K. M. , Ahmed S. M.
Published: June 2009

Cavitation erosion pits and their effects on erosion progression were investigated in detail for SUS 304 stainless steel, α+β brass (60/40), and pure aluminum (Al-99.999 and Al-99.92) by means of vibratory erosion. Two kinds of erosion pits were found on the specimen surfaces, one by microjet impact and the other by shockwave blow. Systematic observations of the feature of microjet-pits with the testing time showed that the sizes and shapes of microjet-pits did not change at all and such pits scarcely played an important role in developing the erosion. Moreover, the feature morphology of eroded surfaces, and dislodged particles and their large sizes revealed that microjet-pits had a limited effect on erosion and that the predominant failure was a fatigue process.
Nonsphericity of Bearing Geometry and Lubrication in Hip Joint Implants
Authors: Wang F. C. , Zhao S. X. , Quiñonez A. Félix , Xu H. , Mei X. S. , Jin Z. M.
Published: June 2009

A general elastohydrodynamic lubrication model was developed to consider the nonsphericity of the bearing geometry in hip joint implants, both under the steady and transient conditions. The articulation between the femoral head and the acetabular cup was represented by a nominal ball-in-socket configuration. The nonsphericity was introduced on the acetabular cup and femoral head bearing surfaces in the form of an ellipsoidal surface represented by variations of the radii of curvature given by the three semi-axis lengths of the ellipsoid with regard to a nominal spherical surface. An appropriate spherical coordinate system and solution domain discretization were used to facilitate the numerical simulations. Both the equivalent discrete spherical convolution model and the corresponding spherical fast Fourier transform technique were used to evaluate the elastic deformation of either the spherical or nonspherical bearing surfaces. A fixed-tracked method was also developed to simulate the complex morphology introduced by moving the interface of the nonspherical bearing surfaces. The general methodology for the nonspherical bearing was first applied to investigate the steady-state elastohydrodynamic lubrication of an ellipsoidal cup articulating against a spherical head in a typical metal-on-metal hip joint implant. Subsequently, the problem of an ellipsoidal head articulating against a spherical cup was considered under the transient conditions. The significance of nonsphericity of bearing geometry in hip joint implants due to manufacturing, designing, and wear was discussed. The results obtained showed that the effect of a nonspherical bearing surface geometry on elastohydrodynamic lubrication was dependent on the orientation, the magnitude, and the deviation direction of the nonsphericity. A well-controlled nonsphericity was seen to be beneficial for improving the lubrication.
Solution of Reynolds Equation in Polar Coordinates Applicable to Nonsymmetric Entrainment Velocities
Authors: Beschorner Kurt , Higgs C. Fred , Lovell Michael
Published: June 2009

Reynolds equation in polar cylindrical (polar) coordinates is used for numerous tribological applications that feature thin fluid films in sliding contacts, such as chemical mechanical polishing and pin-on-disk testing. Although unstated, tribology textbooks and literary resources that present Reynolds equation in polar coordinates often make assumptions that the radial and tangential entrainment velocities are independent of the radial and tangential directions, respectively. The form of polar Reynolds equation is thus typically presented, while neglecting additional terms crucial to obtaining accurate solutions when these assumptions are not met. In the present investigation, the polar Reynolds equation is derived from the cylindrical Navier–Stokes equations without the aforementioned assumptions, and the resulting form is compared with results obtained from more traditionally used forms of the polar Reynolds equation. The polar form of Reynolds equation derived in this manuscript yields results that agree with the commonly used Cartesian form of Reynolds equation but are drastically different from the typically published form of the polar Reynolds equation. It is therefore suggested that the polar form of Reynolds equation proposed in this technical note be utilized when entrainment velocities are known to vary with either radial or angular position.
High-Speed Operation of a Gas-Bearing Supported MEMS-Air Turbine
Authors: Teo C. J. , Liu L. X. , Li H. Q. , Ho L. C. , Jacobson S. A. , Ehrich F. F. , Epstein A. H. , Spakovszky Z. S.
Published: June 2009

Silicon based power micro-electro-mechanical system (MEMS) applications require high-speed microrotating machinery operating stably over a large range of operating conditions. The technical barriers to achieving stable high-speed operation with micro-gas-bearings are governed by (1) stringent fabrication tolerance requirements and manufacturing repeatability, (2) structural integrity of the silicon rotors, (3) rotordynamic coupling effects due to leakage flows, (4) bearing losses and power requirements, and (5) transcritical operation and whirl instability issues. To enable high-power density the micro-turbomachinery must be run at tip speeds comparable to conventional scale turbomachinery. The rotors of the micro-gas turbines are supported by hydrostatic gas journal and hydrostatic gas thrust bearings. Dictated by fabrication constraints the location of the gas journal bearings is at the outer periphery of the rotor. The high bearing surface speeds (target nearly 10×106 mm rpm), the very low bearing aspect ratios (L/D<0.1), and the laminar flow regime in the bearing gap (Re<500) place these micro-bearing designs into unexplored regimes in the parameter space. A gas-bearing supported micro-air turbine was developed with the objectives of demonstrating repeatable, stable high-speed gas-bearing operation and verifying the previously developed micro-gas-bearing analytical models. The paper synthesizes and integrates the established micro-gas-bearing theories and insight gained from extensive experimental work. The characteristics of the new micro-air turbine include a four-chamber journal bearing feed system to introduce stiffness anisotropy, labyrinth seals to avoid rotordynamic coupling effects of leakage flows, a reinforced thrust bearing structural design, a redesigned turbine rotor to increase power, a symmetric feed system to avoid flow and force nonuniformity, and a new rotor micro-fabrication methodology for reduced rotor imbalance. A large number of test devices were successfully manufactured demonstrating repeatable bearing geometry. More specifically, three sets of devices with different journal bearing clearances were produced to investigate the dynamic behavior as a function of bearing geometry. Experiments were conducted to characterize the “as-fabricated” bearing geometry, the damping ratio, and the natural frequencies. Repeatable high-speed bearing operation was demonstrated using isotropic and anisotropic bearing settings reaching whirl-ratios between 20 and 40. A rotor speed of 1.7×106 rpm (equivalent to 370 m/s blade tip speed or a bearing DN number of 7×106 mm rpm) was achieved demonstrating the feasibility of MEMS-based micro-scale rotating machinery and validating key aspects of the micro-gas-bearing theory.
Galling

50

, a Stochastic Measure of Galling Resistance
Authors: Hummel Scott R. , Helm Jeffrey
Published: June 2009

A new parameter called the Galling50 value is proposed to provide a statistically relevant measure of galling resistance. The Galling50 value represents the stress value where galling is expected to occur in 50% of the specimens tested. Galling50 is determined from the analysis of a series of tests that measure the probability of galling at different applied stresses. A method for graphically representing experimental galling data is presented. A sigmoidal function is used to mathematically represent the overall performance of the galling results. Similar to previous test methods, the proposed method provides a single parameter for reporting galling resistance results, making it suitable for comparison between different materials and test conditions. Test results for type 303, 304, and 316 stainless steels are given as an example of the testing and data reduction technique.
Junction Growth and Energy Dissipation at the Very Early Stage of Elastic-Plastic Spherical Contact Fretting
Authors: Ovcharenko A. , Etsion I.
Published: June 2009

The contact area, friction force, and relative displacement evolution at the very early stage of fretting are investigated experimentally. Copper and steel spheres of various diameters are loaded against a hard sapphire flat by a range of normal loads deep into the elastic-plastic regime of deformation. A reciprocating tangential loading is then applied with a maximum loading below the static friction to avoid gross slip. Real-time and in situ direct measurements of the contact area, along with accurate measurements of the friction force and relative displacement, reveal substantial junction growth and energy dissipation mainly in the first loading cycle. The so-called “slip amplitude” is found to be attributed to residual tangential plastic deformation rather than to interfacial slip. Elastic shake-down is observed for the 2.5% hardening steel spheres while plastic shake-down is observed in the case of the elastic perfectly-plastic copper spheres.
Lubricant Depletion and Disk-to-Head Lubricant Transfer at the Head-Disk Interface in Hard Disk Drives
Authors: Ambekar Rohit P. , Bogy David B. , Bhatia C. S.
Published: June 2009

As the head-disk spacing reduces in order to achieve the areal density goal of 1 Tb/in.2, the dynamic stability of the slider is compromised due to a variety of proximity interactions. Lubricant pickup by the slider from the disk is one of the major reasons for the decrease in the stability as it contributes to meniscus forces and contamination. Disk-to-head lubricant transfer leads to lubricant pickup on the slider and also causes depletion of lubricant on the disk. In this paper, we experimentally and numerically investigate the process of disk-to-head lubricant transfer using a half-delubed disk, and we propose a parametric model based on the experimental results. We also investigate the dependence of disk-to-head lubricant transfer on the disk lubricant thickness, lubricant type, and the slider air bearing surface (ABS) design. It is concluded that disk-to-head lubricant transfer occurs without slider-disk contact and there can be more than one timescale associated with the transfer. Furthermore, the transfer increases nonlinearly with increasing disk lubricant thickness. Also, it is seen that the transfer depends on the type of lubricant used and is less for Ztetraol than for Zdol. The slider ABS design also plays an important role, and a few suggestions are made to improve the ABS design for better lubricant performance.
Elastic Contact of Rough Surfaces Subject to Combined Force and Moment
Authors: Sepehri Ali , Farhang Kambiz
Published: June 2009

In this paper we consider the contact between two rectangular rough surfaces that provide normal and tangential contact forces, as well as contact moment, to counteract the net moment imposed by the applied forces. The surfaces are permitted to develop a slight angular misalignment, and thereby contact moment is derived. Through this scheme it is possible to also define elastic contribution to friction, since the half-plane tangential contact force on one side of an asperity is no longer balanced by the half-plane tangential force component on the opposite side. The elastic friction force, however, is shown to be of a much smaller order than the contact normal force.
Elastohydrodynamic Analysis of an Elastomeric Hydraulic Rod Seal During Fully Transient Operation
Authors: Thatte Azam , Salant Richard F.
Published: June 2009

A soft elastohydrodynamic model of a reciprocating elastomeric hydraulic rod seal has been developed. It consists of coupled fluid mechanics, contact mechanics, and deformation analyses. The model has been used to analyze a U-cup lip seal in an injection molding application with a time-varying sealed pressure and rod velocity. Results include the histories of the hydraulic fluid flow rate, fluid transport, mean shear stress on rod, sealing zone length, and friction force on rod, as well as distributions of the fluid pressure, film thickness, and contact pressure.
Derivation of Modified Reynolds Equation: A Porous Media Model With Effects of Electrokinetics
Authors: Li Wang-Long
Published: June 2009

A lubrication theory that includes the effects of electrokinetics and surface microstructure is developed. A porous layer attached to the impermeable substrate is used to model the microstructure on a bearing surface. The Brinkman-extended Darcy equations and Stokes equations are modified by considering the electrical body force and utilized to model the flow in porous media and fluid film, respectively. The stress jump boundary conditions on the porous media/fluid film interface and the effects of viscous shear and electric double layer (EDL) are also considered when deriving the modified Reynolds equation. Under the usual assumptions of lubrication and Debye–Hückel approximation for low surface potential, the velocity distributions, the apparent viscosity, and the modified Reynolds equation are then derived. The apparent viscosity is expressed explicitly as functions of the Debye length, the electroviscosity, the charge density, the stress jump parameter, and the porous parameters (permeability, porosity, and porous film thickness). The considerations of EDL near the interface and the charge density of the flow in the porous media increase the apparent viscosity. The existence of porous film also increases the apparent viscosity as well. Both effects are important for flow within microspacing and lubrication problems. The apparent viscosity and the performance of 1D slider bearings are analyzed and discussed. The results show that the apparent viscosity and the load capacity increase as the permeability decreases, the stress jump parameter decreases, the charge density increases, the inverse Debye length decreases, or the porosity decreases.
A Mass-Conserving Algorithm for Dynamical Lubrication Problems With Cavitation
Authors: Ausas Roberto F. , Jai Mohammed , Buscaglia Gustavo C.
Published: June 2009

A numerical algorithm for fully dynamical lubrication problems based on the Elrod–Adams formulation of the Reynolds equation with mass-conserving boundary conditions is described. A simple but effective relaxation scheme is used to update the solution maintaining the complementarity conditions on the variables that represent the pressure and fluid fraction. The equations of motion are discretized in time using Newmark’s scheme, and the dynamical variables are updated within the same relaxation process just mentioned. The good behavior of the proposed algorithm is illustrated in two examples: an oscillatory squeeze flow (for which the exact solution is available) and a dynamically loaded journal bearing. This article is accompanied by the ready-to-compile source code with the implementation of the proposed algorithm.