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The instability of recombinant basic fibroblast growth factor (bFGF) is a major disadvantage for its therapeutic use and means frequent applications to cells or tissues are required for sustained effects. Originating from silkworm hemolymph, 30Kc19α is a cell-penetrating protein that also has protein stabilization properties. Herein, it is investigated whether fusing 30Kc19α to bFGF can enhance the stability and skin penetration properties of bFGF, which may consequently increase its therapeutic efficacy. The fusion of 30Kc19α to bFGF protein increases protein stability, as confirmed by ELISA. 30Kc19α-bFGF also retains the biological activity of bFGF as it facilitates the migration and proliferation of fibroblasts and angiogenesis of endothelial cells. It is discovered that 30Kc19α can improve the transdermal delivery of a small molecular fluorophore through the skin of hairless mice. Importantly, it increases the accumulation of bFGF and further facilitates its translocation into the skin through follicular routes. Finally, when applied to a skin wound model in vivo, 30Kc19α-bFGF penetrates the dermis layer effectively, which promotes cell proliferation, tissue granulation, angiogenesis, and tissue remodeling. Consequently, the findings suggest that 30Kc19α improves the therapeutic functionalities of bFGF, and would be useful as a protein stabilizer and/or a delivery vehicle in therapeutic applications. [ABSTRACT FROM AUTHOR]

Firmicutes and Bacteroidetes, 2 major phyla of gut microbiota, are involved in lipid and bile acid metabolism to maintain systemic energy homeostasis in host. Recently, accumulating evidence has suggested that dietary changes promptly induce the alteration of abundance of both Firmicutes and Bacteroidetes in obesity and its related metabolic diseases. Nevertheless, the metabolic roles of Firmicutes and Bacteroidetes on such disease states remain unclear. The aim of this study was to determine the effects of antibiotic-induced depletion of Firmicutes and Bacteroidetes on dysregulation of energy homeostasis in obesity. Treatment of C57BL/6J mice with the antibiotics (vancomycin [V] and bacitracin [B]), in the drinking water, before diet-induced obesity (DIO) greatly decreased both Firmicutes and Bacteroidetes in the gut as revealed by pyrosequencing of the microbial 16S rRNA gene. Concomitantly, systemic glucose intolerance, hyperinsulinemia, and insulin resistance in DIO were ameliorated via augmentation of GLP-1 secretion (active form; 2.03-fold, total form; 5.09-fold) independently of obesity as compared with untreated DIO controls. Furthermore, there were increases in metabolically beneficial metabolites derived from the gut. Together, our data suggest that Firmicutes and Bacteroidetes potentially mediate insulin resistance through modulation of GLP-1 secretion in obesity. [ABSTRACT FROM AUTHOR]

Thermal degradation of titanium-containing metal-organic frameworks (MOFs; MIL-125 and MIL-125-NH2 at 350 °C for 6 h in air produced TiO2 nanoparticles of ca. 10 nm in diameter. Scanning electron and transmission electron microscope analyses indicated that those nanoparticles were aggregated randomly within each crystalline particle of their MOF precursors. The TiO2 nanoparticles prepared from MIL-125-NH2 exhibited higher activity for the degradation of 4-chlorophenol under visible light. [ABSTRACT FROM AUTHOR]

The extent of impervious cover in a watershed has been linked to the quality of an urban aquatic environment. The Kyeongan watershed in South Korea was investigated to evaluate the relationship between the total impervious area (TIA) and the aquatic ecosystem of the watershed, including water quality and aquatic life using a relatively high-resolution (0.4m) image. The TIA was found to be approximately 12% of the watershed, which indicates that the quality of its environment was being adversely affected by it. For water quality, Pearson correlation analyses showed that all water quality parameters studied were found to be positively correlated with TIA at p < 0.01, except for nitrate (NO3-). In addition, the zone with a higher TIA was found to have worse water quality. Some water quality parameters, such as nitrite (N02-), total phosphorus, and phosphate (P043-) were highly affected by discharges from wastewater treatment plants. Water quality data suggest that TIA could be used to predict the water quality of streams. For ecological parameters, the diatom index for organic pollution and trophic diatom index were found to be highly correlated with TIA, whereas physical habitat and benthic macroinvertebrates were poorly correlated with TIA. However, the results indicate that the extent of impervious cover can be a useful indicator for predicting the status of specific ecosystem of streams. [ABSTRACT FROM AUTHOR]

Background: In previous studies, oligopeptide corresponding to the cellbinding domains of bone morphogenetic proteins that bind to bone morphogenetic protein receptor enhanced the bone regenerative capacity of bovine bone minerals (BBM). The aim of this study is to evaluate the ability of BBM coated with oligopeptide to promote periodontal regeneration in a 1-wall intrabony defect model in dogs. Methods: The second and third mandibular premolars and first molars of six adult beagles were extracted bilaterally, and the extraction sites were allowed to heal for 10 weeks. The 1-wall intrabony defects were prepared bilaterally on the mesial and distal side of the fourth mandibular premolars. Twenty-four intrabony defects were assigned to four treatment groups: 1) open flap debridement; 2) guided tissue regeneration (GTR); 3) GTR with a collagen membrane and BBM; and 4) GTR with a collagen membrane and BBM coated with the oligopeptide (Pep-BBM). The animals were sacrificed 10 weeks after surgery. For the histometric analysis, defect height, junctional epithelium migration, new cementum, new bone height, and new bone area were measured. New bone volume was measured using microcomputed tomography. Results: Wound healing was generally uneventful. For junctional epithelium migration, the BBM and Pep-BBM groups exhibited mean (± SE) values of 0.53 ± 0.41 and 0.48 ± 0.30 mm, and for new cementum height, 1.71 ± 0.46 and 2.50 ± 2.00 mm, respectively. For junctional epithelium migration and cementum regeneration, there were no significant differences between the two groups. The mean (± SE) values of new bone height and new bone volume in the Pep-BBM group (3.88 ± 0.31 mm and 32.35% ± 9.60%) were significantly greater than the mean values for the BBM group (2.60 ± 0.41 mm and 20.56% ± 1.89%). For bone regeneration, the Pep-BBM group showed superior results compared to the BBM group with statistically significant differences. Conclusions: Through various parameters to evaluate periodontal regeneration, this oligopeptide coating influenced only the ability of BBM to promote bone regeneration in 1-wall intrabony defects in beagles. Junctional epithelium migration and cementum regeneration were not affected by this oligopeptide coating, and further investigations with special focus on regeneration of the periodontal ligament are necessary. [ABSTRACT FROM AUTHOR]

In Alpine ski sport, traditional lap time measurement systems record a skier's departure and arrival using time-of-day timers through wires, which is not cost effective in unofficial or training games. This paper develops a lightweight lap time measurement system using a wireless sensor network, which employs a practical TDMA-based linear wireless sensor network protocol for multihop communications in long strap-shaped environments where sensor nodes are linearly deployed. We evaluate the performance of this protocol through the implementation and deployment of the lap time measurement system. The experimental results show that the proposed protocol transmits data at a success rate of 99.66% and maintains the time synchronization errors between two adjacent nodes within 183 μs without using any other time synchronization protocols. In an experimental deployment for a 1.5 km ski slope covered by 31 nodes, the system provides lap time measurements with a measurement error of 1.255 ms, which satisfies the official measurement error of 5.0 ms. [ABSTRACT FROM AUTHOR]

The article presents a research study that revealed the efficacy of transactivating transcriptional factor (TAT)-mediated chitosan/doxorubicin (DOX) conjugate delivery in slowing down tumor growth. The frequent application of water soluble polymers as drug carriers is explained along with the introduction of protein transduction domain (PTD) into chitosan/DOX conjugates for increased tumor penetration. Materials and methods applied are presented together with the results involving the synthesis of chitosan/DOX/TAT, and the mediation of the TAT peptide.

Background: The ridge-preservation technique has been applied with membrane alone or membrane plus graft. Synthetic peptides, mimicking bioactive growth factor or extracellular matrix protein, have been attempted to provide an active surface of the biomaterials in inducing bone formation while alleviating the limitations of whole protein such as short half-life, immunologic responses. The aim of the present clinical study is to examine the osteogenic effect of synthetic oligopeptide-coated bone mineral compared to bone graft without peptide when applied with collagen membrane in a ridge-preservation technique. Methods: Synthetic oligopeptide from the collagen-binding domain of osteopontin was chemically synthesized and coated onto the surface of bone mineral particulates. Ridge preservations were performed at 44 extraction sites in 42 patients (20 males and 22 females). Analyses of clinical parameters and histomorphometric evaluations were conducted to compare the osteogenic effects of the grafts between baseline and 6 months. Results: In the bone grafts of the control group treated without synthetic peptide, new bone formation was only seen around borders and basal areas. However, new bone was observed broadly in the defects of the test group treated with synthetic peptide-coated bone mineral, as seen not only at peripheries but also in the central and coronal parts of bone cores in the defects. The average percentage of new bone formation was significantly higher in the test group (5.3% ± 8.3% versus 10.4% ± 4.6%). The contact percentages between the graft particles and the new bone were 8.2% ± 11.3% for the control group and 20.4% ± 7.5% for the test group (P<0.05). Conclusions: The ridge-preservation approach using synthetic oligopeptide- coated bone mineral with collagen membrane effectively prevented the resorption of hard tissue with higher bone-to-graft contact, and the oligopeptide-coated bone may be a choice for ridge-preservation procedures while assuring new bone formation. J Periodontol 2011;82: 471-480. [ABSTRACT FROM AUTHOR]

A letter to the editor about decreased heme oxygenase-1 expression in human melanomas is presented.

Background Chronic graft-versus-host disease (cGVHD) is a major complication in longterm survivors of hematopoietic stem cell transplantation (HSCT). Cutaneous manifestations are frequently the presenting features; therefore, the dermatologist needs to be aware of the wide spectrum of cutaneous cGVHD. Methods We retrospectively evaluated patients’ characteristics, clinical, and histological features of cutaneous cGVHD and analyzed factors influencing the severity of cutaneous cGVHD in 100 Korean HSCT recipients between January 1, 1995, and December 31, 2007. Results Clinical manifestations of cutaneous cGVHD mainly presented as lichenoid (60.0%), sclerodermoid (12.0%), or erythematous maculopapular (22.0%) patterns. Other less common findings included xerosis, dyspigmentation, acquired ichthyosis, eczema, exfoliative dermatitis, alopecia, erythema multiforme-like or keratosis pilaris-like eruption. Among 100 patients, 46 patients were investigated for nail involvement, and 29 (63.0%) of them were accompanied with nail abnormalities. Histologically, characteristic lichenoid lesions were observed in 53%, sclerodermoid in 9%, and acute/chronic overlap syndrome in 28% of patients. We also discovered that HSCT from female donors to male recipients increased the severity of cutaneous cGVHD. Conclusions We report a large study about cutaneous cGVHD in Asian patients. Cutaneous cGVHD presented with a wide spectrum of clinical and histological manifestations. [ABSTRACT FROM AUTHOR]

The germinal centre (GC) is a specialized microenvironment where high-affinity antibodies are produced through hypermutation and isotype switching. Follicular dendritic cells (FDCs) are the stromal cells of the GC. The timely expansion and establishment of an FDC network is essential for a protective GC reaction; however, only a few factors modulating FDC development have been recognized. In this study, we report that interleukin-15 (IL-15) enhances human primary FDC proliferation and regulates cytokine secretion. The FDCs express IL-15 receptor complexes for IL-15 signal transduction as well as for specific binding. Moreover, the secretion of chemokines CCL-2, CCL-5, CXCL-5 and CXCL-8 was reduced by blocking IL-15 signalling while the secretion of other cytokines, and the expression of CD14, CD44, CD54 (ICAM-1) and CD106 (VCAM-1) proteins remained unchanged. These results suggest that IL-15 plays a crucial role in the development of FDC networks during GC reaction, offering a new target for immune modulation. [ABSTRACT FROM AUTHOR]

The Na+–HCO3– cotransporter NBCn1 (SLC4A7) has multiple variants depending upon splice domains in the cytoplasmic amino- and carboxy-termini of the protein. In this study, we examined the role of the amino-terminal splice domain containing 123 amino acids (cassette II) in the regulation of NBCn1 function and expression. Polymerase chain reaction detected NBCn1 mRNAs containing cassette II in a variety of tissues. Two variants, NBCn1-B containing cassette II and NBCn1-E lacking cassette II, were expressed in Xenopus oocytes and assessed by two-electrode voltage clamp to measure the ionic current mediated by the transporters. The two variants showed similar current–voltage ( I– V) relations when measured 3–4 days after RNA injection. Replacment of Cl− with gluconate did not affect the I– V relations. When exposed to solutions containing 20–50 mm Na+, the current produced by NBCn1-B was slightly more positive than that produced by NBCn1-E. The two currents were similar at 100 mm Na+. The slope conductances for the two variants were progressively increased at higher Na+ levels, and the increases were parallel and superimposed. Measured at different time points after RNA injection, NBCn1-B produced lower conductance than NBCn1-E at 24–48 h. Protein expression of NBCn1-B was also low at these time points as determined by immunoblot of oocyte membrane preparation. Expressed in opossum kidney (OK) cells, NBCn1-E caused a 1.5-fold increase in ouabain-sensitive production of p-nitrophenol from p-phenyl phosphate compared with control preparations, whereas NBCn1-B had negligible effect. We conclude that the primary function of cassette II is to reduce NBCn1 protein expression. [ABSTRACT FROM AUTHOR]

The excessive proliferation and migration of synoviocytes are well-characterized phenomena that play key roles in the pathophysiology of rheumatoid arthritis (RA). Melatonin has been shown to have potent anti-proliferative effect in various cancer cells such as breast and prostate cancer cells. In this study, we examined the role of melatonin on synoviocyte proliferation in primary cultured human fibroblast-like synoviocytes (FLSs) by analyzing protein expression of P21CIP1 (P21) and P27KIP1 (P27), the cyclin-dependent kinase inhibitors that are important in cell cycle control, and the phosphorylation of mitogen-activated protein kinases (MAPKs). RA-FLS proliferation was determined by a [3H]-thymidine incorporation assay. Western blot analysis was applied to examine the underlying mechanisms of melatonin’s effect. Melatonin inhibited RA-FLS proliferation in a dose-dependent manner. It reduced proliferation of passage 2 FLSs by 25% at 10 μm and by nearly 40% at 100 μm concentrations. The inhibitory effect of melatonin on RA-FLS proliferation was also observed in passages 4 and 6. Melatonin upregulated the expression levels of P21 and P27 dose-dependently (24 hr), induced the phosphorylation of extracellular signal-regulated protein kinase (ERK) time-dependently (10 μm), but did not affect phosphorylation of P38 in RA-FLSs. In addition, the expression of P21 and P27 triggered by melatonin was inhibited by the pretreatment of the ERK inhibitor, PD98059 (10 μm). The anti-proliferative action of melatonin in RA-FLSs was also blocked by PD98059. Taken together, these results suggest that melatonin exerts the inhibitory effect of the proliferation of RA-FLSs through the activation of P21 and P27 mediated by ERK. Hence we suggest that melatonin could be used as a therapeutic agent for the treatment of RA. [ABSTRACT FROM AUTHOR]

Background: The prevalence of allergic contact dermatitis in patients who have previously undergone skin peeling has been rarely studied. Objectives: We compared the frequency of positive patch test (PT) reactions in a patient group with a history of peeling, to that of a control group with no history of peeling. Patients/Methods: The Korean standard series and cosmetic series were performed on a total of 262 patients. 62 patients had previously undergone peeling and 200 patients did not. Results: The frequency of positive PT reactions on Korean standard series was significantly higher in the peeling group compared with that of the control group ( P < 0.05, chi-square test). However, the most commonly identified allergens were mostly cosmetic-unrelated allergens. The frequency of positive PT reactions on cosmetic series in the peeling group was higher than that of the control group, but lacked statistical significance. The frequency (%) of positive PT reactions on cosmetic series in the high-frequency peel group was higher than that of the low-frequency group, but lacked statistical significance. Conclusion: It appears peeling may not generally affect the development of contact sensitization. Further work is required focusing on the large-scale prospective studies by performing a PT before and after peeling. [ABSTRACT FROM AUTHOR]

The protective effect of topiramate (TPM) on seizure-induced neuronal injury is well known; however, its molecular basis has yet to be elucidated. We investigated the effect and signaling mediators of TPM on seizure-induced hippocampal cell death in kainic acid (KA)-treated ICR mice. KA-induced hippocampal cell death was identified by terminal deoxynucleotidyl transferase–mediated dUTP nick end labeling. Immunoreactivity (IR) of p-Erk, p-Jnk, p-P38, and caspase-3, and caspase-3 activity were observed in the hippocampal region 3 h after KA (0.1 μg/5 μL, i.c.v.) administration, and/or TPM (100 mg/kg, i.p.) pretreatment. TPM attenuated seizure-induced neuronal cell death and reduced KA-induced p-Erk IR in the CA3 region of the hippocampus, but did not affect p-Jnk and p-P38. In addition, TPM reduced caspase-3 IR and activation by KA. KA-induced seizures were also suppressed by TPM pretreatment. TPM inhibits seizures, and decreases Erk phosphorylation and caspase-3 activation by KA, thereby contributing to protection from neuronal injury. [ABSTRACT FROM AUTHOR]

The aim of the present study was to test the osteogenic effects of BMP-2 (bone morphogenetic protein-2) gene transfer in BMSCs (bone-marrow stromal cells) and rabbit calvarial bone defects. The pBMP-2-cDNA3.1 plasmid was constructed by subcloning hBMP-2 (human BMP-2) cDNA into the plasmid pcDNA3.1. BMSCs were transfected with a pBMP-2-cDNA3.1–Lipofect-amine™ complex. Transfected cells were observed for localization of the BMP-2 coding plasmid. Also, the level of BMP-2 in the culture medium of transfected cells was measured. The culture medium was collected and we tested whether this medium could induce non-transfected BMSCs to express ALP (alkaline phosphatase) and osteocalcin. The pBMP-2-cDNA3.1 complexes were incorporated into the collagen scaffold and the plasmid-loaded collagen scaffolds were then grafted into rabbit calvarial defects. After 2 weeks, granulation tissue at the grafted site was obtained and mRNA of BMP-2 was examined via RT (reverse transcriptase)–PCR. After 4 and 8 weeks, the animals were killed and the calvarial tissue was excised. After specimen preparation, optical microscopical examination was performed to evaluate bone formation. The results show that transfected cells were able to incorporate the BMP-2 gene into their nuclei. Also, the level of expressed and secreted BMP-2 was significantly higher in transfected cells than in untransfected cells (P<0.01). The retrieved culture medium could induce the expression of ALP and osteocalcin in non-transfected BMSCs. hBMP-2 mRNA was detected at the granulation tissue of experimental animals, but not in control animals after 2 weeks. At both 4 and 8 weeks, experimental groups showed significantly more newly formed bone area than the control group (P<0.01). Therefore pBMP-2-cDNA3.1 gene delivery could induce BMSCs into osteoblastic phenotype cells and enhance bone regeneration in rabbit calvarial bone defects. [ABSTRACT FROM AUTHOR]

Background: Recombinant human bone morphogenic protein-2 stimulates bone augmentation in animal models. The aim of this study was to evaluate the capacity of bovine bone mineral coated with synthetic oligopeptides to enhance guided bone regeneration in the beagle 3-wall defect model and the clinical implications. Methods: The second and fourth mandibular premolars of four adult beagle dogs were extracted bilaterally, and the extraction sites were allowed to heal for 2 months. An L-shaped defect was prepared at the central part of the extraction site with a round bur an a low-speed motor Peptide-coated bone mineral was implanted on one side, and uncoated bone mineral was implanted on the other side. The membrane was tucked underneath the mobilized lingual flap. New bone formation at the test and control sites was determined at 4 weeks. Results: No specimen revealed any evidence of infection or foreign body reaction, and all wounds showed a good healing response. Sites augmented with peptide coated bone mineral and uncoated mineral exhibited excellent maintenance of the ridge contour There was more new bone at sites with peptide-coated bone mineral than at control sites The new bone in sites with peptide coated bone mineral was deposited evenly around the graft material, and bone mineral was integrated fully into the new bone. Conclusion: Deproteinized cancellous bovine bone coated with synthetic oligopeptides enhanced new bone formation, and it seemed to be a better material for guided bone regeneration in the beagle L-shaped defect model. [ABSTRACT FROM AUTHOR]

Melatonin possesses a number of important biologic activities including oncostatic, anti-oxidant, and immunostimulatory actions. This study was designed to assess the effects of melatonin on inflammation-related gene expression in lipopolysaccharide (LPS)-stimulated human peripheral blood mononuclear cells (PBMCs), using CombiMatrix 2K Human Inflammation chip. After pretreatment with melatonin (100 μm) for 4 hr, cells were incubated with LPS (1 μg/mL) for 24 hr. We compared gene expression profiles between LPS-treated, melatonin-treated, LSP/melatonin-treated, and control groups. LPS induced the upregulation of 95 genes, compared with controls. Melatonin pretreatment in LPS-stimulated PBMCs suppressed the expression of 23 genes more than twofold. Interestingly, melatonin showed a suppressive effect on the expression of CC chemokine subfamily genes, including CCL2/MCP1, CCL3/MIP1 α, CCL4/MIP1 β, CCL5/RANTES, CCL8/MCP2, CCL20/MDC, and CCL22/MIP3 α, in LPS-stimulated PBMCs. This result was confirmed by reverse transcriptase polymerase chain reaction. Among the CC chemokine subfamily genes, particularly, the expression of CCL2 and CCL5 was markedly downregulated by melatonin in LPS-stimulated PBMCs. The secretion levels of CCL2 and CCL5 were measured using enzyme-linked immunosorbent assay. Stimulation of PBMCs by LPS induced the secretion of CCL2 (2334.3 ± 161.4 pg/mL, mean ± S.E.M.), whereas melatonin pretreatment (153.0 ± 3.8 pg/mL) inhibited the LPS-induced secretion of CCL2. Melatonin pretreatment (2696.2 ± 385.3 pg/mL) also inhibited the LPS-induced secretion of CCL5 (4679.6 ± 107.5 pg/mL). Taken together, these results suggest that melatonin may have a suppressive effect on LPS-induced expression of CC chemokine genes, especially CCL2 and CCL5, which may explain its beneficial effects in the treatment of various inflammatory conditions. [ABSTRACT FROM AUTHOR]

BACKGROUND: It has previously been shown that ESHAP was an effective mobilization regimen for patients with pretreated lymphoma. To extend these observations, the efficacy and feasibility of rituximab plus ESHAP regimen in CD20+ B-cell NHL were assessed. STUDY DESIGN AND METHODS: The mobilization efficacy and engraftment characteristics were compared in the 22 patients who received the rituximab plus ESHAP (R-ESHAP) with 33 historical controls who received ESHAP. RESULTS: The two treatment groups were well matched in patient characteristics. In the R-ESHAP group, 62 pheresis procedures were performed. Apheresis procedures were started on median Day 16 (range, Days 13-18). The median number of collected CD34+ cells was 10.6 × 106 per kg (range, 4.9 × 106-52.6 × 106/kg). Nineteen (95%) patients achieved optimal peripheral blood hematopoietic progenitor cell (PBPC) collection, defined as at least 5 × 106 CD34+ cells per kg. There were no significant differences between the two groups with respect to mobilization efficacy. Sixteen patients in the R-ESHAP group (73%) underwent autologous peripheral blood progenitor cell transplantation (APBPCT). The median time to absolute neutrophil count at least 0.5 × 109 per L was 10 days (range, 8-17 days), and the median time to a platelet count of at least 20 × 109 per L was 12 days (range, 7-27 days). Lymphocyte recovery was slower in the R-ESHAP group, but the rate of infectious complications was similar in the two groups. In the R-ESHAP group, the 2-year overall survival and progression-free survival after APBPCT were 63.2 and 57.4 percent, respectively. CONCLUSION: Addition of rituximab to ESHAP chemotherapy did not have any adverse effects on PBPC mobilization. Further studies are needed, however, to determine whether addition of rituximab improves outcomes. [ABSTRACT FROM AUTHOR]

Hydrogen-blending effects in flame structure and NO emission behaviour are numerically studied with detailed chemistry in methane–air counterflow diffusion flames. The composition of fuel is systematically changed from pure methane to the blending fuel of methane–hydrogen through H2 molar addition up to 30%. Flame structure, which can be described representatively as a fuel consumption layer and a H2–CO consumption layer, is shown to be changed considerably in hydrogen-blending methane flames, compared to pure methane flames. The differences are displayed through maximum flame temperature, the overlap of fuel and oxygen, and the behaviours of the production rates of major species. Hydrogen-blending into hydrocarbon fuel can be a promising technology to reduce both the CO and CO2 emissions supposing that NOx emission should be reduced through some technologies in industrial burners. These drastic changes of flame structure affect NO emission behaviour considerably. The changes of thermal NO and prompt NO are also provided according to hydrogen-blending. Importantly contributing reaction steps to prompt NO are addressed in pure methane and hydrogen-blending methane flames. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Tannic acids (TAs) are believed to be the key active components in plants, and are believed to be responsible for their anti-inflammatory, anti-viral effects and chemoprevention of cancer. However, the molecular mechanisms for the action of TA are unclear. This study examined the effects of TA on cutaneous inflammation with a human keratinocyte cell line (HaCaT). Interleukin-18 (IL-18) has multiple effects upon various cells involved in inflammatory response. In this study, the IL-18 mRNA expression and protein levels were reduced by a TA pretreatment. UV radiation can trigger the induction of the p38 mitogen-activated protein kinase (MAPK)-dependent signalling cascade. Immunoprecipitation and Western blot analysis was performed to determine if TA regulate the MAPK signalling pathway. TA significantly inhibited the activation of p38 MAPK and extracellular signal-regulated protein kinases. Moreover, TA-inhibited UVB enhanced the expression of the inflammatory mediators, IL-1, IL-6, tumor necrotic factor- α, cyclooxygenase-2 and prostaglandin E2 in UVB-irradiated HaCaT cells. The topical application of TA on mouse skin treated with UVB irradiation has shown that TA inhibited the formation of erythema. These findings suggest that TA has significant anti-inflammatory effects on the UVB-induced response on the skin and may be a candidate natural compound for the regulation of cutaneous inflammation. [ABSTRACT FROM AUTHOR]

Psychological factors are believed to play a role in the pathogenesis of alopecia areata (AA), a frequently encountered hair disorder. In our study, statistically significant elevation of psychological stress was felt by AA patients prior hair loss compared with control, which was strongly believed contributory to hair loss ( t-test, P < 0.01). The corticotropin-releasing hormone (CRH) and proopiomelanocortin (POMC) mRNA have been identified in the basal layer of the epidermis and pilosebaceous units of the normal scalp. And with the recent discovery of melanocytes and dermal fibroblasts capable of corticosterone production, the presence of a local stress response system resembling the hypothalamic–pituitary–adrenal (HPA) axis has been suggested. The local stress response system is involved in regulation of the normal hair cycle, but its precise role in AA is unknown. The influence of a local HPA axis or rather, CRH–POMC axis in AA was investigated by analysing immunohistochemically the expression levels of CRH and POMC peptides, including the adrenocorticotropic hormone (ACTH) and α-melanocyte-stimulating hormone ( α-MSH), in a number of AA lesions and normal scalp (as control). The epidermis and pilosebaceous units of normal scalp stained weakly with CRH, ACTH and α-MSH, whereas those from the affected sites of the AA group showed intense expression of the peptides (chi-square test, P < 0.01). The meaning of this enhanced expression and their role in the pathogenesis of AA should be further evaluated in future. [ABSTRACT FROM AUTHOR]

The existence of specific melatonin-binding sites in lymphoid cells led to the discovery of signal transduction pathway for melatonin in human lymphocytes and immunomodulatory role of melatonin in immune cells. In recent years, transcriptional regulation of melatonin on various transcription factors has been demonstrated. Therefore, this study was designed to assess by cDNA microarray analysis the regulatory effects of melatonin on transcription factors in human peripheral blood mononuclear cells (PBMCs). Forty-six genes were upregulated and 23 were downregulated more than twofold in melatonin-treated PBMCs. Of the more than twofold upregulated transcription factor genes, homeo box A4 ( HOXA4), forkhead box O1A ( FOXO1A), transcription elongation factor B (SIII), polypeptide 3 ( TCEB3), and peroxisome proliferative activated receptor delta ( PPARD) were identified. Of the more than twofold downregulated genes, PHD finger protein 15 ( PHF15) and zinc finger protein 33a ( ZNF33A) were identified. In summary, identification of these genes by cDNA microarray analysis in response to melatonin administration may provide a foundation for further studies on the function of melatonin in human PBMCs. [ABSTRACT FROM AUTHOR]

BMP-2 (bone morphogenetic protein-2) has been used in promoting bone formation and, in combination with various delivery carriers, in bone regeneration or bone tissue-engineering practice. In the present study, BMP-2 was immobilized directly on a GBR (guided bone-regenerative) membrane surface made of chitosan nanofibres, providing a bioactive surface that can enhance bone-regeneration capacity. The BMP-2-conjugated membrane surface retained bioactivity for up to 4 weeks of incubation, as well as holding over 50% of the initial BMP-2 attached. The BMP-2-conjugated surface increased osteoblastic cell attachment in accordance with the amount of BMP-2 conjugated. In addition, the BMP-2-conjugated chitosan membrane significantly promoted cell proliferation, alkaline phosphatase activity, as well as calcium deposition when compared with BMP-2-adsorbed membrane, indicating a stable localization of BMP-2 at the surface of the chitosan membrane. Taking these findings together, the conjugation of BMP-2 on a chitosan nanofibrous membrane would seen to be applicable for inducing significant and localized bone formation in future GBR procedures. [ABSTRACT FROM AUTHOR]

Background: Chitosan is known as a biodegradable and non-toxic natural polymer that enhances wound healing and bone formation. The aims of this study are to evaluate the biocompatibility of chitosan nanofiber membranes and to examine the effect of the chitosan nanofiber membranes on bone regeneration in rabbit calvarial defects. Methods: In vitro cell proliferation tests using human osteosarcoma cell line MG63 and reverse transcription-polymerase chain reaction (RT-PCR) to evaluate the expression of alkaline phosphatase (ALP), collagen, osteocalcin (OCN), and GAPDH were done on chitosan nanofiber membranes. Chitosan nanofiber membranes were implanted in subcutaneous connective tissue and observed for 2, 4, and 6 weeks in rats. Ten-millimeter diameter round cranial defects were made in rabbits and covered by chitosan nanofiber membranes for 4 weeks. Specimens were decalcified and observed by a light microscope. Results: MG63 cells proliferated for 28 days on the chitosan nanofiber membranes and expressed ALP, collagen, OCN, and GAPDH at 2 weeks. Chitosan nanofiber membranes that were grafted into rat subcutaneous tissue maintained their shape and space for bone regeneration for as long as 6 weeks. No inflammation could be seen on the membrane surface or in the surrounding tissues. In the rabbit calvarial defects, new bone filled the defects and fused to the original old bone in 4 weeks. Conclusions: The biocompatibility of the chitosan nanofiber membrane was confirmed, with enhanced bone regeneration and no evidence of an inflammatory reaction. This experiment shows that the novel biodegradable chitosan nanofiber membrane may be useful as a tool for guided bone regeneration. [ABSTRACT FROM AUTHOR]

Melatonin is reported to be an anti-inflammatory agent. No genetic study concerning the association between melatonin and inflammatory disease has yet been reported. Here we performed a polymorphism study on the melatonin receptor type 1B ( MTNR1B) in Korean rheumatoid arthritis (RA) patients and controls. The polymorphism of MTNR1B located in 3′-untranslated region (rs 1562444) was selected for its higher rate of heterozygosity among other single nucleotide polymorphisms (SNPs) in both MTNR1A and MTNR1B genes and investigated in RA patients (n = 173) and healthy controls (n = 195) by polymerase chain reaction-restriction fragment length polymorphism assay using NlaIII restriction enzyme. No statistically significant difference in either genotype distribution or allele frequency was observed between RA patients and controls. The genotype distributions and allele frequencies of rheumatoid factor negative [RF(−)] patients were similar to those of controls. However, statistical analysis of genotype revealed a significant association ( χ2 = 6.42, P = 0.04) is present between RF(+) and MTNR1B SNP (rs 1562444). Although no statistically significant difference in allele frequency between RF(+) and controls was observed ( χ2 = 2.75, P = 0.10), the results might suggest that MTNR1B SNP (rs 1562444) is associated with the presence of RF in RA. This is the first study, to our knowledge, to report a positive genetic relationship between melatonin and RA. [ABSTRACT FROM AUTHOR]

Numerical study with momentum-balanced boundary conditions has been conducted to grasp chemical effects of added CO2, to either fuel- or oxidizer-side on flame structure and NO emission behaviour in CH4O2N2 diffusion flames. Cautious investigation is made for the comparison among the behaviours of principal chain branching and important H-removal key reactions. This describes successfully the reason why flame temperatures for fuel-side dilution are higher than those for oxidizer-side dilution. The role of the principal chain branching reaction is also recognized to be important even in the change of major flame structure caused by chemical effects.The importantly contributing reaction steps to NO production are examined. The reduced production rates of thermal NO and prompt NO due to chemical effects are much more remarkable for fuel-side dilution. It is also found that the reaction step, H+NO+M=HNO+M plays a decisive role of the formation and destruction of prompt NO. Copyright 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In the human resource management literature there is an ongoing debate about which is the key organizational resource: human resource (HR) practices or HR capabilities. Our study attempts to address this debate by examining which resource HR executives in the Asia-Pacific region find to be important for the future organizational and people needs of their firms. Results indicate that HR capabilities are central to organizations. Development of core competencies, agile organizations, and effective management of human resources will be pivotal to responding effectively to future business needs. Results also indicate that the lingering effects of the Asian financial crisis and competition from local and global competitors will affect organizational and people management in the years to come. These findings inform HR practitioners and shed light on the application of the resource-based view of the firm to the study of human resource management. [ABSTRACT FROM AUTHOR]

BACKGROUND: The most reliable index for timing peripheral blood progenitor cell (PBPC) collection following mobilization is still to be determined. The techniques to enumerate peripheral blood (PB) CD34+ cells are expensive and time-consuming. The SE9000 (Sysmex) provides an estimate of immature cells, called hematopoietic progenitor cells (HPC5). The aim of this study was to prospectively evaluate the efficacy of PB HPC levels for timing PBPC harvest. STUDY DESIGN AND METHODS: Thirty-five patients (15 non-Hodgkin's lymphoma and 20 multiple myeloma) were enrolled. PB HPCs and harvested CD34+ cells were counted with the SE9000 and flow cytometry, respectively. Circulating HPCs were monitored daily. PBPC harvest was initiated when HPC levels reached at least 5 per mm³. RESULTS: HPC levels reached 5 per mm³ or more on Median Day 12 (range, days 9 to 16) of mobilizing chemotherapy. The median number of CD34+ cells collected per patient was 19.40 × 106 per kg (range, 1.94 × 106-52.55 × 106 per kg). Both successful and optimal harvest was achieved in 97 percent of patients. PBPCs were successfully harvested in 25 patients (71%) in one session. An optimal harvest in a single session was attained in 16 patients (46%). CONCLUSION: This might be the first prospective study showing the PB HPC level for timing PBPC harvest. [ABSTRACT FROM AUTHOR]

Numerical study on flame structure and NO emission behaviour has been conducted to grasp chemical effects of added H2O on either fuel- or oxidizer-side in CH4O2N2 counterflow diffusion flames. An artificial species, which has the same thermodynamic, transport, and radiation properties of added H2O, is introduced to feasibly isolate the chemical effects. Special concern is focused on the important role of remarkably produced OH radicals due to chemical effects of added H2O on flame structure and NO emission. The reason why the difference of behaviours between the principal chain branching reaction rate and flame temperature appear is attributed to the drastic change of reaction step (R120) from the production to the consumption of OH. It is also, however, seen that the most important contribution of produced OH due to chemical effects of added H2O is through reaction step (R127).The importantly contributing reaction steps to NO production are also examined. The production rates of thermal NO and prompt NO are suppressed by chemical effects of added H2O. The contribution of the reaction steps related to HNO intermediate species to the production of prompt NO is also stressed. Copyright 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Numerical study on flame structure and NO emission is conducted covering a wide range of atmospheric temperature, high temperature, and mild combustion regimes in H2‐Air laminar flames diluted with steam. Special concern is focused on the difference of flame structure and NO emission behaviour between high‐temperature combustion and mild combustion modes. The important role of chemical effects of added steam in flame structure and NO emission behaviour is also discussed. It is seen that there exists an oxidizer‐side temperature limit which the combustion mode changes from high temperature combustion to mild combustion. In high temperature combustion modes the OH production via the reaction step, (‐R23) is suppressed while in mild combustion modes is enhanced by the increase of oxidizer‐side temperature. It is also found that chemical effects of added steam are influenced by the competition between both the reaction steps, (R21) and (‐R23).NO emission index increases with increasing oxidizer‐side temperature and decreases with mole fraction of added steam. The remarkably produced OH due to chemical effects of added steam does not contribute to the increase of NO but plays a role of holdback on NO in thermal mechanism. It is also seen that in both the high temperature combustion and mild combustion modes NO emission indicates a consistently similar tendency, and is consequently recognized that in the whole ranges steam addition suppresses NO emission. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Numerical analysis is conducted to clarify chemical effects of added steam to either fuel- or oxidizer-side on flame structure and NO emission behaviour with detailed chemistry in hydrogen-oxygen-nitrogen diffusion flames. An artificial species, which has the same thermodynamic, transport, and radiation properties to added H2O, is introduced to feasibly isolate chemical effects of added H2O. It is found that the reaction step (-R23) is the starting point to induce chemical effects of added steam. Special concern is, thus, focused on the impact of OH radical on flame structure and NO emission behaviour. A strong dependency of the amount of steam addition on OH radical behaviour is clearly displayed, and this modifies flame structure sufficiently to produce higher flame temperature at more than a certain mole fraction of added steam in comparison to that diluted with artificial species. It is also shown that the reaction step (-R23) is closely related to flame temperature and thereby the location of maximum flame temperature. The behaviour of NO emission index is shown to be greatly influenced by the competition between the reaction steps of (R63) and (R65) in addition to Zeldovich NO. It is, consequently, seen that the intermediate active species, HNO, affects NO emission behaviour remarkably. These results may be helpful to understand the role of recirculated steam in the combustion systems with flue gas recirculation to either fuel- or oxidizer-side. [ABSTRACT FROM AUTHOR]

A numerical study with momentum-balanced boundary conditions has been conducted to grasp the chemical effects of added CO2 to fuel- and oxidizer-sides on flame structure and NO emission behaviour in H2-O2 diffusion flames with varying flame location. A reaction mechanism is proposed to show better agreements with experimental results in CO2-added hydrogen flames. Oxidizer-side dilution results in significantly higher flame temperatures and NO emission. Flame location is dramatically changed due to high diffusivity of hydrogen according to variation of the composition of fuel- and oxidizer-sides. This affects flame structure and NO emission considerably especially the chemical effects of added CO2. The present work also displays separately thermal contribution and prompt NO emission due to the chemical effects caused by thermal dissociation of added CO2 in NO emission behaviour. It is found that flame temperature and the flame location affect the contribution of thermal and prompt NO due to chemical effects considerably in NO emission behaviour. [ABSTRACT FROM AUTHOR]

RecR, together with RecF and RecO, facilitates RecA loading in the RecF pathway of homologous recombinational DNA repair in procaryotes . The human Rad52 protein is a functional counterpart of RecFOR. We present here the crystal structure of RecR from Deinococcus radiodurans (DR RecR). A monomer of DR RecR has a two-domain structure: the N-terminal domain with a helix-hairpin-helix (HhH) motif and the C-terminal domain with a Cys4 zinc-finger motif, a Toprim domain and a Walker B motif. Four such monomers form a ring-shaped tetramer of 222 symmetry with a central hole of 30-35 Å diameter. In the crystal, two tetramers are concatenated, implying that the RecR tetramer is capable of opening and closing. We also show that DR RecR binds to both dsDNA and ssDNA, and that its HhH motif is essential for DNA binding. [ABSTRACT FROM AUTHOR]

A numerical study has been conducted to clearly grasp the impact of chemical effects caused by added CO2 and of flame location on flame structure and NO emission behaviour. Flame location affects the major source reaction of CO formation, CO2+H→CO+OH and the H-removal reaction, CH4+H→CH3+H2. It is, as a result, seen that the reduction of maximum flame temperature due to chemical effects for fuel-side dilution is mainly caused by the competition of the principal chain branching reaction with the reaction, CH4+H→CH3+H2, while that for fuel-side dilution is attributed to the competition of the principal chain branching reaction with the reaction, CO2+H→CO+OH. The importance of the NNH mechanism for NO production, where the reaction pathway is NNH→NH→HNO, is recognized. In C-related reactions most of NO is the direct outcome of (R171) and the contribution of (R171) becomes more and more important with increasing amount of added CO2 as much as the reaction step (R171) competes with the key reaction of thermal mechanism, (R237), for N atom. This indicates a possibility that NO emission in hydrogen flames diluted with CO2 shows less dependent behaviour upon flame temperature. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Numerical study on addition effects of CO and CO2 in fuel side (H2/Ar) on flame structure and NO emission behaviour in counterflow diffusion flame has been conducted with detailed chemistry to fundamentally understand gas combustion of low calorific heating value. A modified Miller–Bowman reaction scheme including a complementary C2-reaction subset is adopted. The radiative heat loss term, which is based on an optically thin model and it especially important at low strain rates, is included to cover the importance of the temperature dependence on NO emission. Special interest is taken to estimate the roles of added CO and CO2 in fuel side on flame structure and NO emission characteristics. Increasing CO concentration in fuel side contributes to the enhancement of combustion due to the increase effect of the concentration of reactive species. The increase of added CO2 concentration in fuel side suppresses overall reaction rate due to the high heat capacity. It is seen that chemical effects due to the breakdown of added CO2 in fuel side make C2-branch chemical species be remarkably formed and the prevailing contribution of prompt NO is a direct outcome of these effects. It is found that in the combined forms of H2/CO/CO2/Ar fuels the effects of added CO and CO2 concentrations in fuel side compete contrarily to each other in NO emission behaviour. Particularly the role of added CO is stressed in the side of restraining prompt NO. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Surface-modified nanospheres can be utilized for targeting drugs and diagnostic agents to the bone and bone marrow while extending their circulation time in the blood stream. The surface modification of poly(lactide-co-glycolide) (PLGA) nanospheres by radioisotope carrying poly(ethylene oxide)-poly (propylene oxide)-poly (ethylene oxide) triblock copolymers (Poloxamer 407) has been assessed by in vitro characterization and in vivo biodistribution studies after intravenous administration of the nanospheres to the mouse. A hydroxyphenylpropionic acid, a ligand for 125I and 131I labeling, was conjugated to the hydroxyl group of the Poloxamer 407 by using dicyclohexyl carbodiimide. The ligand-conjugated Poloxamer 407 was adsorbed onto the surface of PLGA nanospheres. Surface coating was confirmed by measuring both size distribution and the surface charge of the nanospheres. Besides, 125I-labeling efficiency, radiolabeling stability, whole body imaging, and biodistribution of the radioisotope-labeled nanospheres were examined. Ligand-labeled, surface-modified PLGA nanospheres were in 100-nm size ranges, which may be adequate for long-circulation and further bone imaging. 125I-labeling efficiency was >90% and was more stable at human serum for 24 h. A noticeable decrease in liver or spleen uptake was obtained by the surface-modified nanospheres. 125I-labeled nanospheres showed higher blood maintenance and bone uptake compared with stannous colloid with the same size distribution. Therefore, a fully biodegradable, radioisotope-carrying, surface-modified nanosphere system has been developed as a promising tool for targeting bone and bone marrows. © 2003 Wiley Periodicals, Inc. J Biomed Mater Res 67A: 751–760, 2003 [ABSTRACT FROM AUTHOR]

Numerical simulation of CO2 addition effects to fuel and oxidizer streams on flame structure has been conducted with detailed chemistry in H2–O2 diffusion flames of a counterflow configuration. An artificial species, which displaces added CO2 in the fuel- and oxidizer-sides and has the same thermochemical, transport, and radiation properties to that of added CO2, is introduced to extract pure chemical effects in flame structure. Chemical effects due to thermal dissociation of added CO2 causes the reduction flame temperature in addition to some thermal effects. The reason why flame temperature due to chemical effects is larger in cases of CO2 addition to oxidizer stream is well explained though a defined characteristic strain rate. The produced CO is responsible for the reaction, CO2+H=CO+OH and takes its origin from chemical effects due to thermal dissociation. It is also found that the behavior of produced CO mole fraction is closely related to added CO2 mole fraction, maximum H mole fraction and its position, and maximum flame temperature and its position. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The structural similarity between low molecular weight protamine (LMWP), prepared by enzymatic digestion of protamine, and HIV-TAT protein transduction peptide suggested the feasibility of LMWP as an efficient carrier for delivering therapeutic genes while alleviating the cytotoxicity of currently employed gene carriers. LMWP was prepared by enzymatic digestion of protamine with thermolysine. The prepared LMWP peptide and TAT peptide, as well as their complexes with plasmid DNA (pDNA), were examined for cellular uptake behaviors by using confocal microscopy and flow cytometry. The complexation of pDNA and LMWP was monitored by gel retardation test as well as size and zeta potential measurements, and was then further assessed by DNase I protection assay. The transfection efficiency of pDNA/LMWP was examined by varying the pDNA content and charge ratio in the complex, and then compared with that of pDNA/PEI. Cytotoxicity induced by pDNA/LMWP and pDNA/PEI was also examined. Prepared LMWP showed similar transcellular localization behavior and kinetics to those of TAT, and efficiently transferred the pDNA into nucleus and cytoplasm in a short time period. The size and zeta potential of the pDNA/LMWP complex were 120 nm and 30 mV, respectively, which were adequately suitable for cellular uptake. After forming the complex, LMWP appeared to effectively protect pDNA against DNase I attack. The pDNA/LMWP complex showed significantly enhanced gene transfer than both naked pDNA and the pDNA/PEI complex, while exhibiting a markedly reduced cytotoxicity than that of the pDNA/PEI complex. The present study suggested that LMWP could be a useful and safe tool for enhancing delivery of bioactive molecules and therapeutic DNA products into cells when applied in gene therapy. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Numerical study, aimed at the understanding of the flame structure in O2/CO2 recycling combustion system, has been conducted with detailed chemistry. Special concern is focused on addition effect of carbon dioxide on flame structure in H2–O2 counterflow diffusion flame as a simulating configuration. To clarify chemical and thermal effects on flame structure, the comparison between predicted results with a virtual species X to displace the real carbon dioxide and with added carbon dioxide in oxidizer stream is made according to strain rate and the concentration of added CO2. From the systematical comparison of a dominant radical producing reaction with a chain termination reaction the effects of strain rate and composition control of oxidizer stream on flame structure are estimated. It is found that the behaviours of C1- and C2-branch species are a direct outcome of that of produced CO due to the breakdown of added CO2. There exists a temperature dependency in the behaviour of produced CO and this competes for the behaviour of the produced CO with chemical effects due to the backward reaction of CO+OH=CO2+H. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

An independent component model of multiple subjects' positron emission tomography (PET) images is proposed to explore the overall functional components involved in a task and to explain subject specific variations of metabolic activities under altered experimental conditions utilizing the Independent component analysis (ICA) concept. As PET images represent time-compressed activities of several cognitive components, we derived a mathematical model to decompose functional components from cross-sectional images based on two fundamental hypotheses: (1) all subjects share basic functional components that are common to subjects and spatially independent of each other in relation to the given experimental task, and (2) all subjects share common functional components throughout tasks which are also spatially independent. The variations of hemodynamic activities according to subjects or tasks can be explained by the variations in the usage weight of the functional components. We investigated the plausibility of the model using serial cognitive experiments of simple object perception, object recognition, two-back working memory, and divided attention of a syntactic process. We found that the independent component model satisfactorily explained the functional components involved in the task and discuss here the application of ICA in multiple subjects' PET images to explore the functional association of brain activations. Hum. Brain Mapping 18:284–295, 2003. © 2003 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

The dilution effect of air stream according to agent type on flame structure and NO emission behaviour is numerically simulated with detailed chemistry in CH4/air counterflow diffusion flame. The volume percentage of diluents (H2O, CO2, and N2) in air stream is systematically changed from 0 to 10. The radiative heat loss term, based on an optically thin model, is included to clearly describe the flame structure and NO emission behaviour especially at low strain rates. The effect of dilution of air stream on the decrease of maximum flame temperature varies as CO2>H2O>N2, even if heat capacity of H2O is the highest. It is also found that the addition of CO2 shows the tendency towards the reduction of flame temperature in both the thermal and chemical sides, while the addition of H2O enhances the reaction chemically and restrains it thermally due to a super-equilibrium effect of the chain carrier radicals caused by the breakdown of H2O in high-temperature region. The comparison of the nitrogen chemical reaction pathway between the cases of the addition of CO2 and H2O clearly displays that the addition of CO2 is much more effective to reduce NO emission. Copyright © 2002 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The dilution effect of air stream according to agent type on flame structure and NO emission behaviour is numerically analysed with detailed chemistry. The adopted fuel is hydrogen diluted with the argon of volume percentage 50 per cent and the volume percentage of diluents (H2O, CO2 and N2) in air stream is systematically changed from 10 to 50. The radiative heat loss term, based on an optically thin model, is included to clearly describe the flame structure and NO emission behaviour, especially at low strain rates. The effect of dilution of air stream on the decrease of maximum flame temperature varies as CO2>H2O>N2. The qualitative tendency of the numerically predicted mole fractions of H, O and OH is well described using a simplified formula, based on a partial equilibrium concept. It is seen that the H2O addition to air stream is the most effective for reducing NO emission. In the case of the addition of H2O and N2 the NO emission behaviour is governed by the thermal effect and in the case of CO2 addition it is governed by both the thermal effect and the chemical effect. But the chemical effect, which is mainly attributed by the Fenimore mechanism to the breakdown of CO2, is much more predominant in comparison with the thermal effect. Copyright © 2002 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Flame structure and NO emission characteristics in counterflow diffusion flame of blended fuel of H2/CO2/Ar have been numerically simulated with detailed chemistry. The combination of H2, CO2 and Ar as fuel is selected to clearly display the contribution of hydrocarbon products to flame structure and NO emission characteristics due to the breakdown of CO2. A radiative heat loss term is involved to correctly describe the flame dynamics especially at low strain rates. The detailed chemistry adopts the reaction mechanism of GRI 2.11, which consists of 49 species and 279 elementary reactions. All mechanisms including thermal, NO2, N2O and Fenimore are taken into account to separately evaluate the effects of CO2 addition on NO emission characteristics. The increase of added CO2 quantity causes flame temperature to fall since at high strain rates a diluent effect is prevailing and at low strain rates the breakdown of CO2 produces relatively populous hydrocarbon products and thus the existence of hydrocarbon products inhibits chain branching. It is also found that the contribution of NO production by N2O and NO2 mechanisms are negligible and that thermal mechanism is concentrated on only the reaction zone. As strain rate and CO2 quantity increase, NO production is remarkably augmented. Copyright © 2002 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Numerical analysis on flame structure in a counterflow diffusion flame has been conducted for understanding the effects of CO2 addition to fuel, systematically varying initial concentration of CO2 and axial velocity gradient. The effects of CO2 addition to fuel side in a counterflow diffusion flame are globally divided into two categories: diluent effects due to the relative reduction in the concentrations of the reactive species, and direct chemical effects caused by the breakdown of CO2 through the reactions of third-body collision and thermal dissociation. The deflection of CO2 mole fraction profile with mixture fraction clarifies that the converted CO quantity from CO2 is not negligible at low axial velocity gradients. It is also known that the addition of CO2 does not alter the basic skeleton of the H2–O2 reaction mechanism, but contributes to the formation and destruction of hydrocarbon products such as HCO. At high axial velocity gradients the CO converted reaction is suppressed and then CO2 plays the role of a diluent at these conditions. Copyright © 2001 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A numerical study has been conducted for the understanding of flame structure with the fuel composition of 40 per cent CO, 30 per cent H2, 30 per cent N2 and an oxidizer composition of 79 per cent N2 and 21 per cent O2 in a counterflow diffusion flame. Numerical results are obtained for flames over wide-ranged conditions of axial velocity gradients and ambient pressures. Main concern is specially given to effects of axial velocity gradient and ambient pressure on flame structure. It is seen that the role of axial velocity gradient on combustion processes is globally opposite to that of ambient pressure, on the basis of the Damköhler number considering the balance of convection, diffusion, and chemical reaction. That is, chemical non-equilibrium effects become dominant with increasing axial velocity gradient, but are suppressed with increasing ambient pressure. Flame strength is globally weakened by the increase of axial velocity gradient but is augmented by the increase of ambient pressure. However, flame extinction is described better on the basis of only chemical reaction and in this case axial velocity gradient and ambient pressure play a similar role conceptually such that the increase of axial velocity gradient and ambient pressure cause the flame not to be extinguished and extend the extinction limit, respectively. It is suggested that a combustion process like flame extinction is mainly influenced by the competition between the radical formation reaction and the third-body recombination reaction. Copyright © 2001 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]