Sample records for cell chymase limits

  1. Chymase

    DEFF Research Database (Denmark)

    Kosanovic, Djuro; Luitel, Himal; Dahal, Bhola Kumar;


    Limited literature sources implicate mast-cell mediator chymase in the pathologies of pulmonary hypertension and pulmonary fibrosis. However, there is no evidence on the contribution of chymase to the development of pulmonary hypertension associated with lung fibrosis, which is an important medical...... resulted in attenuation of pulmonary hypertension and pulmonary fibrosis, as evident from improved haemodynamics, decreased right ventricular remodelling/hypertrophy, pulmonary vascular remodelling and lung fibrosis. These beneficial effects were associated with a strong tendency of reduction in mast cell...... of the pulmonary arteries.Therefore, chymase plays a role in the pathogenesis of pulmonary hypertension associated with pulmonary fibrosis and may represent a promising therapeutic target. In addition, this study may provide valuable insights on the contribution of chymase in the pulmonary hypertension context...

  2. Stimulation of mucin secretion from human bronchial epithelial cells by mast cell chymase

    Institute of Scientific and Technical Information of China (English)

    Shao-heng HE; Jian ZHENG


    AIM: To investigate the effect ofchymase on the mucin secretion from human bronchial epithelial cells. METHODS:Primarily-cultured human bronchial epithelial (PCHBE) cells and normal human bronchial epithelial (NHBE) cells were cultured with chymase or other stimulus in a mixture of bronchial epithelial growth medium (BEGM) and Dulbecco's modified Eagle's medium (DMEM), and the quantities of stimulatory mucin release were recorded.MUC5AC mucin was measured with an ELISA and dolichos biflorus agglutinin (DBA) mucin was determined with an enzyme linked DBA assay. RESULTS: A dose-dependent secretion of DBA mucin from PCHBE cells was observed with chymase with a maximum secretion of 98 % above baseline being achieved following 3 h incubation.The action of chymase started from 1 h, peaked at 3 h and dramatically decreased at 20 h following incubation.Chymase was able to also stimulate approximately 38 % increase in MUC5AC mucin release from PCHBE cells, and about 121% increase in DBA mucin release from NHBE cells. A chymase inhibitor soybean trypsin inhibitor (SBTI)was able to inhibit up to 85 % chymase induced mucin release, indicating that the enzymatic activity was essential for the actions of chymase on bronchial epithelial cells. CONCLUSION: Chymase is a potent stimulus of mucin secretion from human bronchial epithelial cells. It can contribute to mucus hypersecretion process in the patients with chronic obstructive pulmonary disease or asthma.

  3. Critical role of mast cell chymase in mouse abdominal aortic aneurysm formation

    DEFF Research Database (Denmark)

    Sun, J; Zhang, J; Lindholt, Jes S.


    Mast cell chymase may participate in the pathogenesis of human abdominal aortic aneurysm (AAA), yet a direct contribution of this serine protease to AAA formation remains unknown.......Mast cell chymase may participate in the pathogenesis of human abdominal aortic aneurysm (AAA), yet a direct contribution of this serine protease to AAA formation remains unknown....

  4. GPR30 decreases cardiac chymase/angiotensin II by inhibiting local mast cell number

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zhuo [Department of Anesthesiology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27159-1009 (United States); Department of Cardiology, Jinan Central Hospital, Affiliated with Shandong University, 105 Jiefang Road, Jinan, 250013 (China); Wang, Hao; Lin, Marina [Department of Anesthesiology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27159-1009 (United States); Groban, Leanne, E-mail: [Department of Anesthesiology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27159-1009 (United States); Hypertension and Vascular Disease Center, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157 (United States); Office of Women in Medicine and Science, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157 (United States)


    Chronic activation of the novel estrogen receptor GPR30 by its agonist G1 mitigates the adverse effects of estrogen (E2) loss on cardiac structure and function. Using the ovariectomized (OVX) mRen2.Lewis rat, an E2-sensitive model of diastolic dysfunction, we found that E2 status is inversely correlated with local cardiac angiotensin II (Ang II) levels, likely via Ang I/chymase-mediated production. Since chymase is released from cardiac mast cells during stress (e.g., volume/pressure overload, inflammation), we hypothesized that GPR30-related cardioprotection after E2 loss might occur through its opposing actions on cardiac mast cell proliferation and chymase production. Using real-time quantitative PCR, immunohistochemistry, and immunoblot analysis, we found mast cell number, chymase expression, and cardiac Ang II levels were significantly increased in the hearts of OVX-compared to ovary-intact mRen2.Lewis rats and the GPR30 agonist G1 (50 mg/kg/day, s.c.) administered for 2 weeks limited the adverse effects of estrogen loss. In vitro studies revealed that GPR30 receptors are expressed in the RBL-2H3 mast cell line and G1 inhibits serum-induced cell proliferation in a dose-dependent manner, as determined by cell counting, BrdU incorporation assay, and Ki-67 staining. Using specific antagonists to estrogen receptors, blockage of GPR30, but not ERα or ERβ, attenuated the inhibitory effects of estrogen on BrdU incorporation in RBL-2H3 cells. Further study of the mechanism underlying the effect on cell proliferation showed that G1 inhibits cyclin-dependent kinase 1 (CDK1) mRNA and protein expression in RBL-2H3 cells in a dose-dependent manner. - Highlights: • GPR30 activation limits mast cell number in hearts from OVX mRen2.Lewis rats. • GPR30 activation decreases cardiac chymase/angiotensin II after estrogen loss. • GPR30 activation inhibits RBL-2H3 mast cell proliferation and CDK1 expression.

  5. Inhibition of tryptase and chymase induced nucleated cell infiltration by proteinase inhibitors

    Institute of Scientific and Technical Information of China (English)

    Shao-heng HE; Han-qiu CHEN; Jian ZHENG


    AIM: To investigate the ability of proteinase inhibitors to modulate nucleated cell infiltration into the peritoneum of mice induced by tryptase and chymase. METHODS: Human lung tryptase and skin chymase were purified by a similar procedure involving high salt extraction, heparin agarose affinity chromatography followed by S-200 Sephacryl gel filtration chromatography. The actions of proteinase inhibitors on tryptase and chymase induced nucleated cell accumulation were examined with a mouse peritoneum model. RESULTS: A selective chymase inhibitor Z-Ile-GluPro-Phe-CO2Me (ZIGPPF) was able to inhibit approximately 90% neutrophil, 73% eosinophil, 87% lymphocyte and 60% macrophage accumulation induced by chymase at 16 h following injection. Soy bean trypsin inhibitor (SBTI), chymostatin, and α1-antitrypsin showed slightly less potency than ZIGPPF in inhibition of the actions of chymase. While all tryptase inhibitors tested were able to inhibit neutrophil, eosinophil, and macrophage accumulation provoked by tryptase at 16 h following injection, only leupeptin, APC366, and aprotinin were capable of inhibiting tryptase induced lymphocyte accumulation. The inhibitiors of tryptase tested were also able to inhibit tryptase induced neutrophil and eosinophil accumulation at 6 h following injection. When being injected alone, all inhibitors of chymase and tryptase at the concentrations tested by themselves had no significant effect on the accumulation of nucleated cells in the peritoneum of mice at both 6 h and 16 h. CONCLUSION: Proteinase inhibitors significantly inhibited tryptase and chymase-induced nucleated cell accumulation in vivo, and therefore they are likely to be developed as a novel class of anti-inflammatory drugs.

  6. Extended cleavage specificity of the mast cell chymase from the crab-eating macaque (Macaca fascicularis): an interesting animal model for the analysis of the function of the human mast cell chymase. (United States)

    Thorpe, Michael; Yu, Jing; Boinapally, Vamsi; Ahooghalandari, Parvin; Kervinen, Jukka; Garavilla, Lawrence de; Hellman, Lars


    Serine proteases are the major protein constituents within mast cell secretory granules. These proteases are subdivided into chymases and tryptases depending on their primary cleavage specificity. Here, we present the extended cleavage specificity of the macaque mast cell chymase and compare the specificity with human chymase (HC) and dog chymase (DC) that were produced in the same insect cell expression host. The macaque chymase (MC) shows almost identical characteristics as the HC, including both primary and extended cleavage specificities as well as sensitivity to protease inhibitors, whereas the DC differs in several of these characteristics. Although previous studies have shown that mouse mast cell protease-4 (mMCP-4) is similar in its hydrolytic specificity to the HC, mouse mast cells contain several related enzymes. Thus mice may not be the most appropriate model organism for studying HC activity and inhibition. Importantly, macaques express only one chymase and, as primates, are closely related to human general physiology. In addition, the human and macaque enzymes both cleave angiotensin I (Ang I) in the same way, generating primarily angiotensin II (Ang II) and they do not further degrade the peptide like most rodent enzymes do. Both enzymes also cleave two additional potential in vivo substrates, fibronectin and secretory leukocyte protease inhibitor (SLPI) in a similar way. Given the fact that both HC and MC are encoded by a single gene with high sequence homology and that many physiological processes are similar between these species, the macaque may be a very interesting model to study the physiological role of the chymase and to determine the potency and potential side-effects of various chymase inhibitors designed for therapeutic human use.

  7. Quantitative analysis of tryptase- and chymase-containing mast cells in eosinophilic conditions of cats. (United States)

    Noli, C; Welle, M; Scarampella, F; Abramo, F


    The presence and density of tryptase-positive/chymase-positive mast cells (MCs) (MC(TC)), chymase-positive/tryptase-negative MCs (MCC), and tryptase-positive/chymase-negative MCs (MC(T)) in lesional skin from cats with eosinophilic conditions were investigated. Skin biopsy specimens from eight cats with eosinophilic plaque (three cats), eosinophilic granuloma (two cats), and eosinophilic dermatitis (three cats) were studied. Toluidine blue staining and a double-enzyme-immunohistochemical staining technique were performed to determine MC density and MC subtypes, respectively. MC density varied from 170.3 to 503 cells/mm2 (mean value of 314.9 cells/mm2). In the superficial dermis, 5.9% of the MC belonged to the MC(T), 12.8% to the MC(C), and 81.2% to the MC(TC) subtype. In the deep dermis, 12.8% belonged to the MC(T), 12.8% to the MC(C), and 73.8% to the MC(TC) subtype. It is the first time that MC(C) have been identified. The double-labeling procedure proved to be a reliable tool for identifying simultaneously the presence of MC subtypes in feline skin.

  8. Inhibition of histamine release from human mast cells by natural chymase inhibitors

    Institute of Scientific and Technical Information of China (English)

    Shao-heng HE; Hua XIE; Xiao-jun ZHANG; Xian-jie WANG


    AIM: To investigate the ability of natural chymase inhibitors to modulate histamine release from human mast cells.METHODS: Enzymatically dispersed cells from human lung, tonsil, and skin were challenged with anti-IgE or calcium ionophore A23187 in the absence or presence of the natural chymase inhibitors secretory leukocyte protease inhibitor (SLPI) and α1-antitrypsin, then histamine release was determined. RESULTS: IgE-dependent histamine release from lung, tonsil, and skin mast cells were inhibited by up to 70 %, 61%, and 62%, respectively following incubation with α1-antitrypsin (5000 nmol/L). SLPI 5000 nmol/L was also able to inhibit anti-IgEdependent histamine released from lung, tonsil and skin mast cells by up to approximately 72%, 67%, and 58%,respectively. While neither α1-antitrypsin nor SLPI by themselves altered histamine release from lung, tonsil and skin mast cells, they were able to inhibit calcium ionophore-induced histamine release from lung and tonsil mast cells. CONCLUSION: Both α1-antitrypsin and SLPI could potently inhibit IgE-dependent and calcium ionophoreinduced histamine release from dispersed human lung, tonsil, and skin mast cells in a concentration-dependent manner, which suggested that they were likely to play a protective role in mast cell associated diseases including allergy.

  9. IL-15 constrains mast cell-dependent antibacterial defenses by suppressing chymase activities. (United States)

    Orinska, Zane; Maurer, Marcus; Mirghomizadeh, Farhad; Bulanova, Elena; Metz, Martin; Nashkevich, Natalia; Schiemann, Florian; Schulmistrat, Jan; Budagian, Vadim; Giron-Michel, Julien; Brandt, Ernst; Paus, Ralf; Bulfone-Paus, Silvia


    Sepsis remains a global clinical problem. By using the mouse cecal ligation and puncture model of sepsis, here we identify an important aspect of mast cell (MC)-dependent, innate immune defenses against Gram-negative bacteria by demonstrating that MC protease activity is regulated by interleukin-15 (IL-15). Mouse MCs express both constitutive and lipopolysaccharide-inducible IL-15 and store it intracellularly. Deletion of Il15 in mice markedly increases chymase activities, leading to greater MC bactericidal responses, increased processing and activation of neutrophil-recruiting chemokines, and significantly higher survival rates of mice after septic peritonitis. By showing that intracellular IL-15 acts as a specific negative transcriptional regulator of a mouse MC chymase (mast cell protease-2), we provide evidence that defined MC protease activity is transcriptionally regulated by an intracellularly retained cytokine. Our results identify an unexpected breach in MC-dependent innate immune defenses against sepsis and suggest that inhibiting intracellular IL-15 in MCs may improve survival from sepsis.

  10. Modulation of enzymatic activity of human mast cell tryptase and chymase by protease inhibitors

    Institute of Scientific and Technical Information of China (English)

    HEShao-Heng; CHENPu; CHENHan-Qiu


    AIM: To investigate the actions of protease inhibitors on the enzymatic activities of tryptase and chymase in similarexperimental systems. METHODS: Human lung tryptase and human skin chymase were purified by a similarprocedure involving high salt extraction of tryptase, heparin agarose affinity chromatography, and S-200 Sephacrylgel filtration chromatography. Actions of protease inhibitors on tryptase and chymase activities were examined byenzyme assays. RESULTS: The specific activities of tryptase and chymase were 2.1 kU/g protein and 4.9 kU/g protein, respectively. Both preparations showed a single diffuse band on SDS-PAGE. Among non-native proteaseinhibitors, N-(1-hydroxy-2-naphthoyl)-L- arginyl-L-prolinamide hydrochloride (HNAP), leupeptin, antipain,benzamidine, and protamine inhibited more than 90 % enzymatic activity of tryptase, whereas soy bean trypsininhibitor (SBTI), Z-Ile-Glu-Pro-Phe-CO2Me (ZIGPPM) and chymostatin inhibited more than 95 % enzymaticactivity of chymase. Native protease inhibitors α-antitrypsin and secretory leukocyte protease inhibitor (SLPI)inhibited more than 90 % enzymatic activity of chymase, but lactoferrin appeared to enhance chymase enzymaticactivity. All the 3 inhibitors had weak inhibitory actions on tryptase. CONCLUSION: The protease inhibitorstested had relatively good selectivity to either tryptase or chymase.

  11. Altered expression of mast cell chymase and tryptase and of c-Kit in human cutaneous scar tissue. (United States)

    Hermes, B; Feldmann-Böddeker, I; Welker, P; Algermissen, B; Steckelings, M U; Grabbe, J; Henz, B M


    In order to explore a possible involvement of mast cells during human wound healing, we studied sections from scars (4-369-d-old) (N = 20) and normal skin (N = 10) for mast-cell-specific tryptase and chymase by enzyme histochemistry, for the stem cell factor receptor c-Kit and the melanosomal marker TA99 by immunohistochemistry, and for simultaneous c-Kit expression and avidin fluorescence by double staining. Enzyme activities and mRNA expression were also studied in tissue extracts. Chymase-reactive mast cell numbers as well as chymase activity and mRNA expression were reduced in all scars, whereas overall numbers of tryptase-reactive cells did not differ from normal skin, although tryptase activity and mRNA expression were increased in scar extracts. In contrast, numbers of c-Kit positive cells were significantly increased in old scars, and in the mid and lower dermis of all scars. A marked reduction of c-Kit reactivity was noted, however, in avidin-positive dermal mast cells and in epidermal basal cells, despite unchanged numbers of melanosome-positive cells, with an associated overall decrease of c-Kit mRNA in scar extracts. These data thus show that numbers of resident mast cells are very low in human cutaneous scars, suggesting massive mediator release from these cells into fresh wounds. Downregulation of stem cell factor receptors may also prevent these cells from increasing in number even in old scars. Instead, scar tissue is populated by a mast cell subpopulation that is chymase-, avidin-, tryptase +, c-Kit +, reflecting most probably an increased immigration and/or proliferation of immature mast cells and their precursors.

  12. Chymase-producing cells of the innate immune system are required for decidual vascular remodeling and fetal growth. (United States)

    Meyer, Nicole; Woidacki, Katja; Knöfler, Martin; Meinhardt, Gudrun; Nowak, Désirée; Velicky, Philipp; Pollheimer, Jürgen; Zenclussen, Ana C


    Intrauterine growth restriction (IUGR) is caused by insufficient remodeling of spiral arteries (SAs). The mechanism underlying the relevance of natural killer cells (NKs) and mast cells (MCs) for SA remodeling and its effects on pregnancy outcome are not well understood. We show that NK depletion arrested SA remodeling without affecting pregnancy. MC depletion resulted in abnormally remodeled SAs and IUGR. Combined absence of NKs and MCs substantially affected SA remodeling and impaired fetal growth. We found that α-chymase mast cell protease (Mcpt) 5 mediates apoptosis of uterine smooth muscle cells, a key feature of SA remodeling. Additionally, we report a previously unknown source for Mcpt5: uterine (u) NKs. Mice with selective deletion of Mcpt5(+) cells had un-remodeled SAs and growth-restricted progeny. The human α-chymase CMA1, phylogenetic homolog of Mcpt5, stimulated the ex vivo migration of human trophoblasts, a pre-requisite for SA remodeling. Our results show that chymases secreted by uMCs and uNKs are pivotal to the vascular changes required to support pregnancy. Understanding the mechanisms underlying pregnancy-induced vascular changes is essential for developing therapeutic options against pregnancy complications associated with poor vascular remodeling.

  13. Airway responsiveness to mannitol in asthma is associated with chymase-positive mast cells and eosinophilic airway inflammation

    DEFF Research Database (Denmark)

    Sverrild, Asger; Bergqvist, Anders; Baines, Katherine J;


    BACKGROUND: Airway hyperresponsiveness (AHR) to inhaled mannitol is associated with indirect markers of mast cell activation and eosinophilic airway inflammation. It is unknown how AHR to mannitol relates to mast cell phenotype, mast cell function and measures of eosinophilic inflammation in airway...... tissue. We compared the number and phenotype of mast cells, mRNA expression of mast cell-associated genes and number of eosinophils in airway tissue of subjects with asthma and healthy controls in relation to AHR to mannitol. METHODS: Airway hyperresponsiveness to inhaled mannitol was measured in 23 non......-smoking, corticosteroid-free asthmatic individuals and 10 healthy controls. Mast cells and eosinophils were identified in mucosal biopsies from all participants. Mast cells were divided into phenotypes based on the presence of chymase. mRNA expression of mast cell-associated genes was measured by real-time PCR. RESULTS...

  14. Predomination of IL-17-producing tryptase-positive/chymase-positive mast cells in azoospermic chronic testicular inflammation. (United States)

    Chen, S-J; Duan, Y-G; Haidl, G; Allam, J-P


    Chronic testicular inflammation and infection have been regarded as important factors in the pathogenesis of azoospermia. As key effector cells in innate and adaptive immune system, mast cells (MCs) were observed in inflammation and autoimmune disease. Furthermore, increased expression of tryptase-positive MCs has been reported in testicular disorders associated with male infertility/subfertility. However, little is known about the potential relationship between MCs and chronic testicular inflammation in azoospermic patients. Moreover, the preferential expression of MCs' subtypes in testis of these patients is still far from being understood. Thus, this study aimed to investigate characteristics of testicular MCs as well as their subtypes in azoospermic men with chronic testicular inflammation (AZI, n = 5) by immunohistochemical techniques. Our results showed significant increase of MCs in AZI, and more importantly, considerable numbers of tryptase-positive/chymase-positive MCs could also be demonstrated in AZI, when compared to control groups representing azoospermia without chronic testicular inflammation (AZW, n = 5) and normal spermatogenesis (NT, n = 5) respectively. Most interestingly, immunofluorescence staining revealed autoimmune-associated interleukin (IL)-17-producing MCs in AZI, whereas co-expression of MC markers with tumour necrosis factor (TNF)-α, IL-10 and IL-1β could not be detected. In conclusion, AZI is associated with significant increase of tryptase-positive/chymase-positive MCs expressing IL-17, and these MCs might contribute to the pathogenesis of AZI.

  15. The autocrine role of tryptase in pressure overload-induced mast cell activation, chymase release and cardiac fibrosis

    Directory of Open Access Journals (Sweden)

    Jianping Li


    Results and conclusion: The results indicate the presence of PAR-2 on MCs and that tryptase inhibition and nedocromil prevented TAC-induced fibrosis and increases in MC density, activation, and chymase release. Tryptase also significantly increased chymase concentration in ventricular slice culture media, which was prevented by the tryptase inhibitor. Hydroxyproline concentration in culture media was significantly increased with tryptase incubation as compared to the control group and the tryptase group incubated with nafamostat mesilate or chymostatin. We conclude that tryptase contributes to TAC-induced cardiac fibrosis primarily via activation of MCs and the amplified release of chymase.

  16. Effect of chymase on intraocular pressure in rabbits. (United States)

    Konno, Takashi; Maruichi, Midori; Takai, Shinji; Oku, Hidehiro; Sugiyama, Tetsuya; Uchibori, Takehiro; Nagai, Akihiko; Kogi, Kentaro; Ikeda, Tsunehiko; Miyazaki, Mizuo


    Chymase is a chymotrypsin-like serine protease that is stored exclusively in the secretory granules of mast cells and converts big endothelins to endothelin-1 (1-31). The aim of this study was to evaluate the effect of chymase on intraocular pressure in rabbits. Chymase injection (3 and 10 mU) resulted in a trend toward increased intraocular pressure and a significant increase in intraocular pressure at a dose of 10 mU compared with the control. A specific chymase inhibitor, Suc-Val-Pro-Phe(P)(OPh)(2), attenuated the ocular hypertension induced by chymase. Endothelin-1 (1-31) also caused ocular hypertension, which was inhibited by a selective endothelin ET(A) receptor antagonist, cyclo(D-Asp-Pro-D-Val-Leu-D-Trp) (BQ-123). Moreover, chymase-induced ocular hypertension was inhibited by BQ-123. These results suggest that chymase influences the regulation of intraocular pressure, and it is likely that the formation of endothelin-1 (1-31) and subsequent activation of endothelin ET(A) receptors are involved in the development of ocular hypertension induced by chymase.

  17. The combined action of mast cell chymase, tryptase and carboxypeptidase A3 protects against melanoma colonization of the lung

    DEFF Research Database (Denmark)

    Grujic, Mirjana; Paivandy, Aida; Gustafson, Ann-Marie;


    not been clear. Here we addressed this issue by assessing mice lacking either the chymase Mcpt4, the tryptase Mcpt6 or carboxypeptidase A3 (Cpa3), as well as mice simultaneously lacking all three proteases, in a model of melanoma dissemination from blood to the lung. Although mice with individual...

  18. Role of Chymase in the Development of Liver Cirrhosis and Its Complications: Experimental and Human Data (United States)

    Sansoè, Giovanni; Aragno, Manuela; Mastrocola, Raffaella; Mengozzi, Giulio; Novo, Erica; Parola, Maurizio


    Background Tissue Angiotensin II (Ang-II), produced through local non ACE-dependent pathways, stimulates liver fibrogenesis, renal vasoconstriction and sodium retention. Aim To highlight chymase-dependent pathway of Ang-II production in liver and kidney during cirrhosis development. Methods Liver histology, portal pressure, liver and kidney function, and hormonal status were investigated in rat liver cirrhosis induced through 13 weeks of CCl4, with or without chymase inhibitor SF2809E, administered between 4th and 13th CCl4 weeks; liver and kidney chymase immunolocation and Ang-II content were assessed. Chymase immunohistochemistry was also assessed in normal and cirrhotic human liver, and chymase mRNA transcripts were measured in human HepG2 cells and activated hepatic stellate cells (HSC/MFs) in vitro. Results Rats receiving both CCl4 and SF2809E showed liver fibrotic septa focally linking portal tracts but no cirrhosis, as compared to ascitic cirrhotic rats receiving CCl4. SF2809E reduced portal pressure, plasma bilirubin, tissue content of Ang-II, plasma renin activity, norepinephrine and vasopressin, and increased glomerular filtration rate, water clearance, urinary sodium excretion. Chymase tissue content was increased and detected in α-SMA-positive liver myofibroblasts and in kidney tubular cells of cirrhotic rats. In human cirrhosis, chymase was located in hepatocytes of regenerative nodules. Human HepG2 cells and HSC/MFs responded to TGF-β1 by up-regulating chymase mRNA transcription. Conclusions Chymase, through synthesis of Ang-II and other mediators, plays a role in the derangement of liver and kidney function in chronic liver diseases. In human cirrhosis, chymase is well-represented and apt to become a future target of pharmacological treatment. PMID:27637026

  19. Chymase activities and survival in endotoxin-induced human chymase transgenic mice. (United States)

    Rafiq, Kazi; Fan, Yu-Yan; Sherajee, Shamshad J; Takahashi, Yoshimasa; Matsuura, Junji; Hase, Naoki; Mori, Hirohito; Nakano, Daisuke; Kobara, Hideki; Hitomi, Hirofumi; Masaki, Tsutomu; Urata, Hidenori; Nishiyama, Akira


    We examined the effects of overexpressed human chymase on survival and activity in lipopolysaccharide (LPS)-treated mice. Human chymase transgenic (Tg) and wild-type C57BL/6 (WT) mice were treated with LPS (0.03, 0.1 and 0.3 mg/day; intraperitoneal) for 2 weeks. Treatment with 0.03 mg LPS did not affect survival in either WT or Tg mice. WT mice were not affected by 0.1 mg/day of LPS, whereas 25% of Tg mice died. Survival of mice treated with 0.3 mg/day of LPS was 87.5% and 0% in WT and Tg, respectively. LPS-induced increases in chymase activity in the heart and skin were significantly greater in Tg than WT mice. These data suggest a possible contribution of human chymase activation to LPS-induced mortality.

  20. Discovery of potent, selective chymase inhibitors via fragment linking strategies. (United States)

    Taylor, Steven J; Padyana, Anil K; Abeywardane, Asitha; Liang, Shuang; Hao, Ming-Hong; De Lombaert, Stéphane; Proudfoot, John; Farmer, Bennett S; Li, Xiang; Collins, Brandon; Martin, Leslie; Albaugh, Daniel R; Hill-Drzewi, Melissa; Pullen, Steven S; Takahashi, Hidenori


    Chymase plays an important and diverse role in the homeostasis of a number of cardiovascular processes. Herein, we describe the identification of potent, selective chymase inhibitors, developed using fragment-based, structure-guided linking and optimization techniques. High-concentration biophysical screening methods followed by high-throughput crystallography identified an oxindole fragment bound to the S1 pocket of the protein exhibiting a novel interaction pattern hitherto not observed in chymase inhibitors. X-ray crystallographic structures were used to guide the elaboration/linking of the fragment, ultimately leading to a potent inhibitor that was >100-fold selective over cathepsin G and that mitigated a number of liabilities associated with poor physicochemical properties of the series it was derived from.

  1. Molecular modeling study for inhibition mechanism of human chymase and its application in inhibitor design.

    Directory of Open Access Journals (Sweden)

    Mahreen Arooj

    Full Text Available Human chymase catalyzes the hydrolysis of peptide bonds. Three chymase inhibitors with very similar chemical structures but highly different inhibitory profiles towards the hydrolase function of chymase were selected with the aim of elucidating the origin of disparities in their biological activities. As a substrate (angiotensin-I bound crystal structure is not available, molecular docking was performed to dock the substrate into the active site. Molecular dynamics simulations of chymase complexes with inhibitors and substrate were performed to calculate the binding orientation of inhibitors and substrate as well as to characterize conformational changes in the active site. The results elucidate details of the 3D chymase structure as well as the importance of K40 in hydrolase function. Binding mode analysis showed that substitution of a heavier Cl atom at the phenyl ring of most active inhibitor produced a great deal of variation in its orientation causing the phosphinate group to interact strongly with residue K40. Dynamics simulations revealed the conformational variation in region of V36-F41 upon substrate and inhibitor binding induced a shift in the location of K40 thus changing its interactions with them. Chymase complexes with the most active compound and substrate were used for development of a hybrid pharmacophore model which was applied in databases screening. Finally, hits which bound well at the active site, exhibited key interactions and favorable electronic properties were identified as possible inhibitors for chymase. This study not only elucidates inhibitory mechanism of chymase inhibitors but also provides key structural insights which will aid in the rational design of novel potent inhibitors of the enzyme. In general, the strategy applied in the current study could be a promising computational approach and may be generally applicable to drug design for other enzymes.

  2. Interaction of human chymase with ginkgolides, terpene trilactones of Ginkgo biloba investigated by molecular docking simulations. (United States)

    Dubey, Amit; Marabotti, Anna; Ramteke, Pramod W; Facchiano, Angelo


    The search for natural chymase inhibitors has a good potential to provide a novel therapeutic approach against the cardiovascular diseases and other heart ailments. We selected from literature 20 promising Ginkgo biloba compounds, and tested them for their potential ability to bind chymase enzyme using docking and a deep analysis of surface pocket features. Docking results indicated that the compounds may interact with the active site of human chymase, with favorable distinct interactions with important residues Lys40, His57, Lys192, Phe191, Val146, Ser218, Gly216, and Ser195. In particular, proanthocyanidin is the one with the best-predicted binding energy, with seven hydrogen bonds. Interestingly, all active G. biloba compounds have formed the hydrogen bond interactions with the positively charged Lys192 residue at the active site, involved in the mechanism of pH enhancement for the cleavage of angiotensin I site. Ginkgolic acid and proanthocyanidin have better predicted binding energy towards chymase than other serine proteases, i.e kallikrein, tryptase and elastase, suggesting specificity for chymase inhibition. Our study suggests these G. biloba compounds are a promising starting point for developing chymase inhibitors for the potential development of future drugs.

  3. Pericytes limit tumor cell metastasis

    DEFF Research Database (Denmark)

    Xian, Xiaojie; Håkansson, Joakim; Ståhlberg, Anders


    Previously we observed that neural cell adhesion molecule (NCAM) deficiency in beta tumor cells facilitates metastasis into distant organs and local lymph nodes. Here, we show that NCAM-deficient beta cell tumors grew leaky blood vessels with perturbed pericyte-endothelial cell-cell interactions...... and deficient perivascular deposition of ECM components. Conversely, tumor cell expression of NCAM in a fibrosarcoma model (T241) improved pericyte recruitment and increased perivascular deposition of ECM molecules. Together, these findings suggest that NCAM may limit tumor cell metastasis by stabilizing...... the microvessel wall. To directly address whether pericyte dysfunction increases the metastatic potential of solid tumors, we studied beta cell tumorigenesis in primary pericyte-deficient Pdgfb(ret/ret) mice. This resulted in beta tumor cell metastases in distant organs and local lymph nodes, demonstrating a role...

  4. Function of chymase in the heart angiotensin Ⅱ forma- tion in transgenic mice

    Institute of Scientific and Technical Information of China (English)


    The myosin light chain 2 promoter-human heart chymase (MLC2-hChymase) transgenic mice founded by our laboratory were used as the model to study the function of chymase in the heart angiotension Ⅱ (Ang Ⅱ) formation and heart remodeling. Tissue-specific expression of human heart chymase gene and transcriptional expression of typeⅠ and type Ⅲ collagens genes were analyzed by RT-PCR. Activities of chymase, ACE and the levels of AngⅡ in heart and plasma were determined with radioimmunoassay (RIA) kit. Activity of heart matrix metalloproteinase-9 (MMP-9) was detected using gelatin zymography. The cardiac hypertrophic phenotypes were also observed with the physiological and morphological methods. The results in the MLC2-hChymase transgenic mice indicated: (ⅰ) human heart chymase gene was expressed specially in the heart; (ⅱ) heart chymase activity increased markedly in the transgenic mice vs non-transgenic mice (control) (0.27±0.07 U/mg vs. 0.15±0.02 U/mg, P<0.05) with no significant difference in ACE activity (0.17±0.03 U/mg vs. 0.18±0.02 U/mg); (ⅲ) heart AngⅡ content increased 3-fold (1984±184 vs. 568±88 pg/g protein, P<0.05) but was unchanged in plasma (218±106 vs. 234±66 pg/mL); (ⅳ) both MMP-9 activity and collagen Ⅰ mRNA level increased significantly in the heart (P<0.05) but there was neither significant increase in colla-gen Ⅲ mRNA nor in the ratio of Ⅰ/ Ⅲ collagen mRNA levels; (ⅴ) the MLC2-hChymase transgenic mice showed no significant changes in blood pressure, heart-rate, ratio of heart/body weight and cardiomyocyte diameter compared to the control. This suggests that heart AngⅡ formation cata-lyzed through overexpression of human heart chymase gene in the heart of transgenic mice might activate MMP-9 to influence collagen metabolism in cardiac interstitial and to be involved in the process of heart remodeling.

  5. Mast Cells Induce Vascular Smooth Muscle Cell Apoptosis via a Toll-Like Receptor 4 Activation Pathway.

    NARCIS (Netherlands)

    Dekker, W.K.; Tempel, D.; Bot, I.; Biessen, E.A.; Joosten, L.A.B.; Netea, M.G.; Meer, J.W.M. van der; Cheng, C.; Duckers, H.J.


    OBJECTIVE: Activated mast cells (MCs) release chymase, which can induce vascular smooth muscle cell (VSMC) apoptosis leading to plaque destabilization. Because the mechanism through which MCs release chymase in atherosclerosis is unknown, we studied whether MC-associated VSMC apoptosis is regulated

  6. Crystal structure of a complex of human chymase with its benzimidazole derived inhibitor

    Energy Technology Data Exchange (ETDEWEB)

    Matsumoto, Yoshiyuki; Kakuda, Shinji; Koizumi, Masahiro; Mizuno, Tsuyoshi; Muroga, Yumiko; Kawamura, Takashi; Takimoto-Kamimura, Midori, E-mail: [Teijin Institute for Bio-medical Research, 4-3-2 Asahigaoka, Hino, Tokyo 191-8512 (Japan)


    The crystal structure of human chymase complexed with a novel benzimidazole inhibitor, TJK002, was determined at 2.8 Å resolution. The present study shows that the benzimidazole ring of the inhibitor takes the stable stacking interaction with the protonated His57 in the catalytic domain of human chymase. The crystal structure of human chymase complexed with a novel benzimidazole inhibitor, TJK002, was determined at 2.8 Å resolution. The X-ray crystallographic study shows that the benzimidazole inhibitor forms a non-covalent interaction with the catalytic domain of human chymase. The hydrophobic fragment of the inhibitor occupies the S1 pocket. The carboxylic acid group of the inhibitor forms hydrogen bonds with the imidazole N(∊) atom of His57 and/or the O(γ) atom of Ser195 which are members of the catalytic triad. This imidazole ring of His57 induces π–π stacking to the benzene ring of the benzimidazole scaffold as P2 moiety. Fragment molecular orbital calculation of the atomic coordinates by X-ray crystallography shows that this imidazole ring of His57 could be protonated with the carboxyl group of Asp102 or hydroxyl group of Ser195 and the stacking interaction is stabilized. A new drug design strategy is proposed where the stacking to the protonated imidazole of the drug target protein with the benzimidazole scaffold inhibitor causes unpredicted potent inhibitory activity for some enzymes.

  7. A combination of receptor-based pharmacophore modeling & QM techniques for identification of human chymase inhibitors.

    Directory of Open Access Journals (Sweden)

    Mahreen Arooj

    Full Text Available Inhibition of chymase is likely to divulge therapeutic ways for the treatment of cardiovascular diseases, and fibrotic disorders. To find novel and potent chymase inhibitors and to provide a new idea for drug design, we used both ligand-based and structure-based methods to perform the virtual screening(VS of commercially available databases. Different pharmacophore models generated from various crystal structures of enzyme may depict diverse inhibitor binding modes. Therefore, multiple pharmacophore-based approach is applied in this study. X-ray crystallographic data of chymase in complex with different inhibitors were used to generate four structure-based pharmacophore models. One ligand-based pharmacophore model was also developed from experimentally known inhibitors. After successful validation, all pharmacophore models were employed in database screening to retrieve hits with novel chemical scaffolds. Drug-like hit compounds were subjected to molecular docking using GOLD and AutoDock. Finally four structurally diverse compounds with high GOLD score and binding affinity for several crystal structures of chymase were selected as final hits. Identification of final hits by three different pharmacophore models necessitates the use of multiple pharmacophore-based approach in VS process. Quantum mechanical calculation is also conducted for analysis of electrostatic characteristics of compounds which illustrates their significant role in driving the inhibitor to adopt a suitable bioactive conformation oriented in the active site of enzyme. In general, this study is used as example to illustrate how multiple pharmacophore approach can be useful in identifying structurally diverse hits which may bind to all possible bioactive conformations available in the active site of enzyme. The strategy used in the current study could be appropriate to design drugs for other enzymes as well.

  8. Activation of chymase in the paraquat—induced pulmonary fibrosis in hamsters

    Institute of Scientific and Technical Information of China (English)

    OritK; SuzuY


    Angiotensin Ⅱ has been reported to have an important role in the fibrotic response to tissue injuries:it stimulates the proliferation of fibroblasts via activation of angiotensin Ⅱ(AT1) receptor.In the present study,whether Ang Ⅱ forming enzymes,angiotensin converting enzyme(ACE) and chymase,which were activated in pulmonary fibrosis induced by paraquat(PQ) were examined in hamsters.PQ was administered subcutaneously once a week at a dose of 6mg·kg-1 for four weeks and the 18mg·kg-1 for six weeks.Interstitial and superficial pulmonary fibrosis were found five weeks after administration.Chymase activity was significantly increased in the PQ group when compared with saline group.ACE activity,on the other hand,was not significantly different.There data support the possible role of angiotensin Ⅱ,via activation of chymase,to the PQ-induced pulmonary fibrosis.

  9. Assessing Possibilities & Limits for Solar Cells

    CERN Document Server

    Nayak, Pabitra K; Cahen, David


    What are the solar cell efficiencies that we can strive towards? We show here that several simple criteria, based on cell and module performance data, serve to evaluate and compare all types of today's solar cells. Analyzing these data allows to gauge in how far significant progress can be expected for the various cell types and, most importantly from both the science and technology points of view, if basic bounds, beyond those known today, may exist, that can limit such progress. This is important, because half a century after Shockley and Queisser (SQ) presented limits, based on detailed balance calculations for single absorber solar cells, those are still held to be the only ones, we need to consider; most efforts to go beyond SQ are directed towards attempts to circumvent them, primarily via smart optics, or optoelectronics. After formulating the criteria and analyzing known loss mechanisms, use of such criteria suggests - additional limits for newer types of cells, Organic and Dye-Sensitized ones, and th...

  10. [Stem cells: limitations and opportunities in Peru]. (United States)

    Amiel-Pérez, José; Casado, Fanny


    Stem cells are defined as rare cells that are characterized by asymmetric division, a process known as self-renewal, and the potential to differentiate into more than one type of terminally differentiated cell. There is a diversity of stem cells including embryonic stem cells, which exist only during the first stages of human development, and many adult stem cells depending on the specific tissues from where they derive or the ones derived from mesenchymal or stromal tissues. On the other hand, there are induced pluripotent stem cells generated by genetic engineering with similar properties to embryonic stem cells that are derived from adult tissues without the ethical and legal limitations. In all cases, there are many questions that are being addressed by research in basic sciences to better inform clinical practice. In Peru, there is much to do refining techniques and improving methodologies, which requires experience, proper facilities and highly specialized human resources. However, there are interesting efforts to place Peruvian stem cell research in the international scientific arena.

  11. What are the limits to cell plasticity?

    Institute of Scientific and Technical Information of China (English)

    Jane Taylor; Ian Wilmut; Gareth Sullivan


    @@ It is now well established that the fate of a somatic cell is not fixed rigidly and that there is a significant degree of cell plasticity. The term plasticity refers to the opportunity to change differentiated cells from one cell type to another. Over the past 25 years a series of papers have each demonstrated that plasticity is wider than had previously been under-stood [1-4]. An exciting recent article by Thomas Vierbuchen and colleagues at Stanford University extended that series by describing a method for directly re-programming mouse fibroblast cells into neurons without the need to generate a stem cell intermediary.

  12. Cell Reprogramming, IPS Limitations, and Overcoming Strategies in Dental Bioengineering

    Directory of Open Access Journals (Sweden)

    Gaskon Ibarretxe


    Full Text Available The procurement of induced pluripotent stem cells, or IPS cells, from adult differentiated animal cells has the potential to revolutionize future medicine, where reprogrammed IPS cells may be used to repair disease-affected tissues on demand. The potential of IPS cell technology is tremendous, but it will be essential to improve the methodologies for IPS cell generation and to precisely evaluate each clone and subclone of IPS cells for their safety and efficacy. Additionally, the current state of knowledge on IPS cells advises that research on their regenerative properties is carried out in appropriate tissue and organ systems that permit a safe assessment of the long-term behavior of these reprogrammed cells. In the present paper, we discuss the mechanisms of cell reprogramming, current technical limitations of IPS cells for their use in human tissue engineering, and possibilities to overcome them in the particular case of dental regeneration.

  13. Changes of chymase, angiotensin converting enzyme and angiotensin Ⅱ type 1 receptor expressions in the hamster heart during the development of heart failure

    Institute of Scientific and Technical Information of China (English)

    CHEN Peng-min; LENG Xi-gang; FAN Li-li; MA Jun; WANG Ya-fang; CHEN Lan-ying


    Background Little is known about the role of dual angiotensin Ⅱ forming pathways during heart failure. In the present study, the changes of chymase and angiotensin converting enzyme (ACE) expressions in the failing hearts of hamsters were analysed.Methods Heart failure was induced by ligation of left anterior descending branch of the coronary artery. Chymase, ACE and angiotensin Ⅱ type 1 receptor (AT1R) mRNA levels were analysed by reverse transcription polymerase chain reaction (RT-PCR). The activities of chymase and ACE were determined by radioimmunoassay (RIA). Myocardial collagen fibre analysis was performed under optical microscope.Results Left ventricular systolic pressure (LVSP) and maximum left ventricular developed pressure increase rate (dp/dtmax, mmHg/s) gradually moved lower at 2, 3, 4 and 8 weeks after operation. On the other hand, left ventricular end-diastolic pressure (LVEDP) increased gradually after operation. Compared with the control group (3.55±0.06, 4.79±0.70), the heart weight/body weight ratio in operation group had increased significantly at 4 weeks and 8 weeks (4.28±0.43, 6.17±0.73) (P<0.01). Collagen staining showed that the quantity of myocardial collagen fibre increased significantly in the operation group. RT-PCR showed that the chymase mRNA level in the operation group was consistently greater than that in the control group. AT1R mRNA level was also increased significantly at 3 weeks and 4 weeks, both being 1.3 times that of the control group (P<0.01), whereas ACE mRNA level was not changed. Higher activity of chymase was detected in operation group, being 4, 8, 13 and 19 times that of the control group at 2, 3, 4 and 8 weeks (P<0.01), respectively. ACE activity was also significantly higher at the same time, being 7, 10, 10 and 3.5 times that of the control (P<0.01). Angiotensin Ⅱ (Ang Ⅱ) level in operation group increased significantly, being 2.5, 2.7, 3.5 and 2 times that of the control group at 2, 3, 4 and 8 weeks

  14. Fundamental Limits to Collective Concentration Sensing in Cell Populations (United States)

    Fancher, Sean; Mugler, Andrew


    The precision of concentration sensing is improved when cells communicate. Here we derive the physical limits to concentration sensing for cells that communicate over short distances by directly exchanging small molecules (juxtacrine signaling), or over longer distances by secreting and sensing a diffusive messenger molecule (autocrine signaling). In the latter case, we find that the optimal cell spacing can be large, due to a trade-off between maintaining communication strength and reducing signal cross-correlations. This leads to the surprising result that sparsely packed communicating cells sense concentrations more precisely than densely packed communicating cells. We compare our results to data from a wide variety of communicating cell types.

  15. Fundamental Limitations to Plasmonic Hot-Carrier Solar Cells. (United States)

    Zhang, Yu; Yam, ChiYung; Schatz, George C


    Detailed balance between photon-absorption and energy loss constrains the efficiency of conventional solar cells to the Shockley-Queisser limit. However, if solar illumination can be absorbed over a wide spectrum by plasmonic structures, and the generated hot-carriers can be collected before relaxation, the efficiency of solar cells may be greatly improved. In this work, we explore the opportunities and limitations for making plasmonic solar cells, here considering a design for hot-carrier solar cells in which a conventional semiconductor heterojunction is attached to a plasmonic medium such as arrays of gold nanoparticles. The underlying mechanisms and fundamental limitations of this cell are studied using a nonequilibrium Green's function method, and the numerical results indicate that this cell can significantly improve the absorption of solar radiation without reducing open-circuit voltage, as photons can be absorbed to produce mobile carriers in the semiconductor as long as they have energy larger than the Schottky barrier rather than above the bandgap. However, a significant fraction of the hot-carriers have energies below the Schottky barrier, which makes the cell suffer low internal quantum efficiency. Moreover, quantum efficiency is also limited by hot-carrier relaxation and metal-semiconductor coupling. The connection of these results to recent experiments is described, showing why plasmonic solar cells can have less than 1% efficiency.

  16. The Shockley-Queisser limit for nanostructured solar cells

    CERN Document Server

    Xu, Yunlu; Munday, Jeremy N


    The Shockley-Queisser limit describes the maximum solar energy conversion efficiency achievable for a particular material and is the standard by which new photovoltaic technologies are compared. This limit is based on the principle of detailed balance, which equates the photon flux into a device to the particle flux (photons or electrons) out of that device. Nanostructured solar cells represent a new class of photovoltaic devices, and questions have been raised about whether or not they can exceed the Shockley-Queisser limit. Here we show that single-junction nanostructured solar cells have a theoretical maximum efficiency of 42% under AM 1.5 solar illumination. While this exceeds the efficiency of a non- concentrating planar device, it does not exceed the Shockley-Queisser limit for a planar device with optical concentration. We conclude that nanostructured solar cells offer an important route towards higher efficiency photovoltaic devices through a built-in optical concentration.

  17. Detailed balance limit efficiency of silicon intermediate band solar cells

    Institute of Scientific and Technical Information of China (English)

    Cao Quan; Ma Zhi-Hua; Xue Chun-Lai; Zuo Yu-Hua; Wang Qi-Ming


    The detailed balance method is used to study the potential of the intermediate band solar cell (IBSC),which can improve the efficiency of the Si-based solar cell with a bandgap between 1.1 eV to 1.7 eV. It shows that a crystalline silicon solar cell with an intermediate band located at 0.36 eV below the conduction band or above the valence band can reach a limiting efficiency of 54% at the maximum light concentration,improving greatly than 40.7% of the Shockley-Queisser limit for the single junction Si solar cell. The simulation also shows that the limiting efficiency of the siliconbased solar cell increases as the bandgap increases from 1.1 eV to 1.7 eV,and the amorphous Si solar cell with a bandgap of 1.7 eV exhibits a radiative limiting efficiency of 62.47%,having a better potential.

  18. Limitations in plasticity of the T-cell receptor repertoire.


    Nanda, N K; Apple, R; Sercarz, E.


    How constrained is T-cell recognition? Is a truncated T-cell receptor (TCR) repertoire, missing half of its V beta components (where V indicates variable), still broad enough to produce an antigen-specific T-cell response to all determinants? These questions can be answered for certain T-cell antigenic determinants whose response in the wild type is limited to specific gene segments. Our results show that mice with such a deletion in their TCR V beta genes (V beta truncated haplotype, Va beta...

  19. Fundamental limits to collective concentration sensing in cell populations

    CERN Document Server

    Fancher, Sean


    The precision of concentration sensing is improved when cells communicate. Here we derive the physical limits to concentration sensing for cells that communicate over short distances by directly exchanging small molecules (juxtacrine signaling), or over longer distances by secreting and sensing a diffusive messenger molecule (autocrine signaling). In the latter case, we find that the optimal cell spacing can be large, due to a tradeoff between maintaining communication strength and reducing signal cross-correlations. This leads to the surprising result that autocrine signaling allows more precise sensing than juxtacrine signaling for sufficiently large populations. We compare our results to data from a wide variety of communicating cell types.

  20. The generalized Shockley-Queisser limit for nanostructured solar cells (United States)

    Xu, Yunlu; Gong, Tao; Munday, Jeremy N.


    The Shockley-Queisser limit describes the maximum solar energy conversion efficiency achievable for a particular material and is the standard by which new photovoltaic technologies are compared. This limit is based on the principle of detailed balance, which equates the photon flux into a device to the particle flux (photons or electrons) out of that device. Nanostructured solar cells represent a novel class of photovoltaic devices, and questions have been raised about whether or not they can exceed the Shockley-Queisser limit. Here we show that single-junction nanostructured solar cells have a theoretical maximum efficiency of ˜42% under AM 1.5 solar illumination. While this exceeds the efficiency of a non-concentrating planar device, it does not exceed the Shockley-Queisser limit for a planar device with optical concentration. We consider the effect of diffuse illumination and find that with optical concentration from the nanostructures of only × 1,000, an efficiency of 35.5% is achievable even with 25% diffuse illumination. We conclude that nanostructured solar cells offer an important route towards higher efficiency photovoltaic devices through a built-in optical concentration.

  1. Limiter (United States)

    Cohen, S.A.; Hosea, J.C.; Timberlake, J.R.


    A limiter with a specially contoured front face is provided. The front face of the limiter (the plasma-side face) is flat with a central indentation. In addition, the limiter shape is cylindrically symmetric so that the limiter can be rotated for greater heat distribution. This limiter shape accommodates the various power scrape-off distances lambda p, which depend on the parallel velocity, V/sub parallel/, of the impacting particles.

  2. Differentiating skin-limited and multisystem Langerhans cell histiocytosis (United States)

    Simko, Stephen J.; Garmezy, Benjamin; Abhyankar, Harshal; Lupo, Philip J.; Chakraborty, Rikhia; Lim, Karen Phaik Har; Shih, Albert; Hicks, M. John; Wright, Teresa S.; Levy, Moise L.; McClain, Kenneth L.; Allen, Carl E.


    Objective To identify features associated with multisystem involvement and therapeutic failure in patients with skin Langerhans cell histiocytosis (LCH). Study design We reviewed medical records of 71 consecutive LCH patients with skin involvement evaluated at Texas Children’s Hospital and analyzed clinical features, laboratory results, and presence of circulating cells with the BRAF-V600E mutation, with respect to initial staging and clinical outcomes. Results Skin disease in patients older than 18 months at diagnosis was associated with presence of multisystem disease (OR 9.65, 95% CI 1.17–79.4). Forty percent of patients referred for presumed skin-limited LCH had underlying multisystem involvement, half of these with risk-organ involvement. Patients with skin-limited LCH had 3-year progression-free survival (PFS) of 89% after initial therapy, and none developed multisystem disease. Patients with skin/multisystem involvement had 3 year PFS of 44% with vinblastine/prednisone therapy, and risk-organ involvement did not correlate with failure to achieve non-active disease. Circulating cells with BRAF-V600E were detected at higher frequency in multisystem patients (8/11 skin/multisystem, 1/13 skin-limited, P=0.002). Conclusions Skin-limited LCH requires infrequent therapeutic intervention and has lower risk of progression relative to skin plus multisystem LCH. The less aggressive clinical course and lack of circulating cells with BRAF-V600E mutation in skin-limited LCH suggest a different mechanism of disease origin compared with multisystem or risk-organ disease. PMID:25441388

  3. Induced pluripotent stem cells in dermatology: potentials, advances, and limitations. (United States)

    Bilousova, Ganna; Roop, Dennis R


    The discovery of methods for reprogramming adult somatic cells into induced pluripotent stem cells (iPSCs) has raised the possibility of producing truly personalized treatment options for numerous diseases. Similar to embryonic stem cells (ESCs), iPSCs can give rise to any cell type in the body and are amenable to genetic correction by homologous recombination. These ESC properties of iPSCs allow for the development of permanent corrective therapies for many currently incurable disorders, including inherited skin diseases, without using embryonic tissues or oocytes. Here, we review recent progress and limitations of iPSC research with a focus on clinical applications of iPSCs and using iPSCs to model human diseases for drug discovery in the field of dermatology.

  4. Quantifying losses and thermodynamic limits in nanophotonic solar cells (United States)

    Mann, Sander A.; Oener, Sebastian Z.; Cavalli, Alessandro; Haverkort, Jos E. M.; Bakkers, Erik P. A. M.; Garnett, Erik C.


    Nanophotonic engineering shows great potential for photovoltaics: the record conversion efficiencies of nanowire solar cells are increasing rapidly and the record open-circuit voltages are becoming comparable to the records for planar equivalents. Furthermore, it has been suggested that certain nanophotonic effects can reduce costs and increase efficiencies with respect to planar solar cells. These effects are particularly pronounced in single-nanowire devices, where two out of the three dimensions are subwavelength. Single-nanowire devices thus provide an ideal platform to study how nanophotonics affects photovoltaics. However, for these devices the standard definition of power conversion efficiency no longer applies, because the nanowire can absorb light from an area much larger than its own size. Additionally, the thermodynamic limit on the photovoltage is unknown a priori and may be very different from that of a planar solar cell. This complicates the characterization and optimization of these devices. Here, we analyse an InP single-nanowire solar cell using intrinsic metrics to place its performance on an absolute thermodynamic scale and pinpoint performance loss mechanisms. To determine these metrics we have developed an integrating sphere microscopy set-up that enables simultaneous and spatially resolved quantitative absorption, internal quantum efficiency (IQE) and photoluminescence quantum yield (PLQY) measurements. For our record single-nanowire solar cell, we measure a photocurrent collection efficiency of >90% and an open-circuit voltage of 850 mV, which is 73% of the thermodynamic limit (1.16 V).

  5. SnS Thin Film Solar Cells: Perspectives and Limitations

    Directory of Open Access Journals (Sweden)

    Simone Di Mare


    Full Text Available Thin film solar cells have reached commercial maturity and extraordinarily high efficiency that make them competitive even with the cheaper Chinese crystalline silicon modules. However, some issues (connected with presence of toxic and/or rare elements are still limiting their market diffusion. For this reason new thin film materials, such as Cu2ZnSnS4 or SnS, have been introduced so that expensive In and Te, and toxic elements Se and Cd, are substituted, respectively, in CuInGaSe2 and CdTe. To overcome the abundance limitation of Te and In, in recent times new thin film materials, such as Cu2ZnSnS4 or SnS, have been investigated. In this paper we analyze the limitations of SnS deposition in terms of reproducibility and reliability. SnS deposited by thermal evaporation is analyzed by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and atomic force microscopy. The raw material is also analyzed and a different composition is observed according to the different number of evaporation (runs. The sulfur loss represents one of the major challenges of SnS solar cell technology.

  6. Functional limitations of plasmacytoid dendritic cells limit type I interferon, T cell responses and virus control in early life.

    Directory of Open Access Journals (Sweden)

    Elodie Belnoue

    Full Text Available Infant mortality from viral infection remains a major global health concern: viruses causing acute infections in immunologically mature hosts often follow a more severe course in early life, with prolonged or persistent viral replication. Similarly, the WE strain of lymphocytic choriomeningitis virus (LCMV-WE causes acute self-limiting infection in adult mice but follows a protracted course in infant animals, in which LCMV-specific CD8⁺ T cells fail to expand and control infection. By disrupting type I IFNs signaling in adult mice or providing IFN-α supplementation to infant mice, we show here that the impaired early life T cell responses and viral control result from limited early type I IFN responses. We postulated that plasmacytoid dendritic cells (pDC, which have been identified as one major source of immediate-early IFN-I, may not exert adult-like function in vivo in the early life microenvironment. We tested this hypothesis by studying pDC functions in vivo during LCMV infection and identified a coordinated downregulation of infant pDC maturation, activation and function: despite an adult-like in vitro activation capacity of infant pDCs, the expression of the E2-2 pDC master regulator (and of critical downstream antiviral genes such as MyD88, TLR7/TLR9, NF-κB, IRF7 and IRF8 is downregulated in vivo at baseline and during LCMV infection. A similar pattern was observed in response to ssRNA polyU, a model ligand of the TLR7 viral sensor. This suggests that the limited T cell-mediated defense against early life viral infections is largely attributable to / regulated by infant pDC responses and provides incentives for novel strategies to supplement or stimulate immediate-early IFN-α responses.

  7. Thermodynamic limit of bifacial double-junction tandem solar cells (United States)

    Ryyan Khan, M.; Alam, Muhammad A.


    A traditional single-junction solar panel cannot harness ground-scattered light (albedo reflectance, RA ), and also suffers from the fundamental sub-band-gap and the thermalization losses. In this paper, we explain how a "bifacial tandem" panel would dramatically reduce these losses, with corresponding improvement in thermodynamic performance. Our study predicts (i) the optimum combination of the band-gaps, empirically given by Eg(t ) o p t≈Eg(b ) o p t(2 +RA)/3 +(1 -RA) and the (ii) corresponding optimum normalized output power given by ηT(op t ) *≈RA (2 ηSJ (o p t ) ) +(1 -RA ) ηDJ (o p t ) . Empirically, ηT(op t ) * interpolates between the thermodynamic efficiency limit of classical double-junction tandem cell ( ηDJ ) and twice that of a single-junction cell ( ηSJ ). We conclude by explaining how the fundamental loss mechanisms evolve with RA in a bifacial tandem cell.

  8. Hydrogenation of Dislocation-Limited Heteroepitaxial Silicon Solar Cells: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Bolen, M. L.; Grover, S.; Teplin, C. W.; Bobela, D.; Branz, H. M.; Stradins, P.


    Post-deposition hydrogenation by remote plasma significantly improves performance of heteroepitaxial silicon solar cells. Heteroepitaxial deposition of thin crystal silicon on sapphire for photovoltaics (PV) is an excellent model system for the study and improvement of deposition on inexpensive Al2O3-coated (100) biaxially-textured metal foils. Without hydrogenation, PV conversion efficiencies are less than 1% on our model system. Performance is limited by carrier recombination at electrically active dislocations that result from lattice mismatch, and other defects. We find that low-temperature hydrogenation at 350 degrees C is more effective than hydrogenation at 610 degrees C. In this work, we use measurements such as spectral quantum efficiency, secondary ion mass spectrometry (SIMS), and vibrational Si-H spectroscopies to understand the effects of hydrogenation on the materials and devices. Quantum efficiency increases most at red and green wavelengths, indicating hydrogenation is affecting the bulk more than the surface of the cells. SIMS shows there are 100X more hydrogen atoms in our cells than dangling bonds along dislocations. Yet, Raman spectroscopy indicates that only low temperature hydrogenation creates Si-H bonds; trapped hydrogen does not stably passivate dangling-bond recombination sites at high temperatures.

  9. Inhibition of tryptase release from human colon mast cells by protease inhibitors

    Institute of Scientific and Technical Information of China (English)

    Shao-Heng He; Hua Xie


    AIM: To investigate the ability of protease inhibitors to modulate tryptase release from human colon mast cells.METHODS: Enzymatically dispersed cells from human colon were challenged with anti-IgE or calcium ionophore A23187 in the absence or presence of tryptase and chymase inhibitors,and tryptase release was determined.RESULTS: IgE dependent tryptase release from colon mast cells was inhibited by up to approximately 37%, 40% and 36.6% by chymase inhibitors Z-Ile-Glu-Pro-Phe-CO2Me (ZIGPFM), N-tosyl-L-phenylalanyl-chloromethyl ketone (TPCK), and α1-antitrypsin, respectively. Similarly, the inhibitors of tryptase leupeptin, N-tosyl-L-lysine chloromethyl ketone (TLCK) and lactoferrin were also able to inhibit anti-IgE induced tryptase release by a maximum of 39.4%,47.6% and 36.6%, respectively. The inhibitory actions of chymase inhibitors, but not tryptase inhibitors on colon mast cells were enhanced by preincubation of them with cells for 20 min before challenged with anti-IgE. At a concentration of 10 μg/mL, protamine was able to inhibit anti-IgE and calcium ionophore induced tryptase release. However, at 100 μg/mL, protamine elevated tryptase levels in supernatants.A specific inhibitor of aminopeptidase amastatin had no effect on anti-IgE induced tryptase release. The significant inhibition of calcium ionophore induced tryptase release was also observed with the inhibitors of tryptase and chymase examined. The inhibitors tested by themselves did not stimulate tryptase release from colon mast cells.CONCLUSION: It was demonstrated for the first time that both tryptase and chymase inhibitors could inhibit IgE dependent and calcium ionophore induced tryptase release from dispersed colon mast cells in a concentration dependent of manner, which suggest that they are likely to be developed as a novel class of anti-inflammatory drugs to treat chronic of colitis in man.

  10. The Limits of Linked Suppression for Regulatory T cells

    Directory of Open Access Journals (Sweden)

    Toshiro eIto


    Full Text Available Background: We have previously found that CD4+CD25+ regulatory T cells (T regs can adoptively transfer tolerance after its induction with co-stimulatory blockade in a mouse model of murine cardiac allograft transplantation. In these experiments, we tested an hypothesis with three components: 1 the T regs that transfer tolerance have the capacity for linked suppression, 2 the determinants that stimulate the T regs are expressed by the indirect pathway, and 3 the donor peptides contributing to these indirect determinants are derived from donor MHC antigens. Methods: 1st heart transplants were performed from the indicated donor strain to B10.D2 recipients along with co-stimulatory blockade treatment (250μg i.p. injection of MR1 on day 0 and 250μg i.p. injection of CTLA-4 Ig on day 2. At least 8 weeks later a 2nd heart transplant was performed to a new B10.D2 recipient that had been irradiated with 450 cGy. This recipient was given 40 x 106 naïve B10.D2 spleen cells plus 40 x 106 B10.D2 spleen cells from the first (tolerant recipient. We performed 3 different types of heart transplants with using various donor.Results: 1. T regs suppress the graft rejection in an antigen-specific manner. 2. T regs generated in the face of MHC disparities suppress the rejection of grafts expressing third party MHC along with tolerant MHC. Conclusion:The limits of linkage appear to be quantitative and not universally determined by either the indirect pathway or by peptides of donor MHC antigens.

  11. Speed-limited particle-in-cell (SLPIC) simulation (United States)

    Werner, Gregory; Cary, John; Jenkins, Thomas


    Speed-limited particle-in-cell (SLPIC) simulation is a new method for particle-based plasma simulation that allows increased timesteps in cases where the timestep is determined (e.g., in standard PIC) not by the smallest timescale of interest, but rather by an even smaller physical timescale that affects numerical stability. For example, SLPIC need not resolve the plasma frequency if plasma oscillations do not play a significant role in the simulation; in contrast, standard PIC must usually resolve the plasma frequency to avoid instability. Unlike fluid approaches, SLPIC retains a fully-kinetic description of plasma particles and includes all the same physical phenomena as PIC; in fact, if SLPIC is run with a PIC-compatible timestep, it is identical to PIC. However, unlike PIC, SLPIC can run stably with larger timesteps. SLPIC has been shown to be effective for finding steady-state solutions for 1D collisionless sheath problems, greatly speeding up computation despite a large ion/electron mass ratio. SLPIC is a relatively small modification of standard PIC, with no complexities that might degrade parallel efficiency (compared to PIC), and is similarly compatible with PIC field solvers and boundary conditions.

  12. Potential and Limitation of HLA-Based Banking of Human Pluripotent Stem Cells for Cell Therapy

    Directory of Open Access Journals (Sweden)

    Casimir de Rham


    Full Text Available Great hopes have been placed on human pluripotent stem (hPS cells for therapy. Tissues or organs derived from hPS cells could be the best solution to cure many different human diseases, especially those who do not respond to standard medication or drugs, such as neurodegenerative diseases, heart failure, or diabetes. The origin of hPS is critical and the idea of creating a bank of well-characterized hPS cells has emerged, like the one that already exists for cord blood. However, the main obstacle in transplantation is the rejection of tissues or organ by the receiver, due to the three main immunological barriers: the human leukocyte antigen (HLA, the ABO blood group, and minor antigens. The problem could be circumvented by using autologous stem cells, like induced pluripotent stem (iPS cells, derived directly from the patient. But iPS cells have limitations, especially regarding the disease of the recipient and possible difficulties to handle or prepare autologous iPS cells. Finally, reaching standards of good clinical or manufacturing practices could be challenging. That is why well-characterized and universal hPS cells could be a better solution. In this review, we will discuss the interest and the feasibility to establish hPS cells bank, as well as some economics and ethical issues.

  13. The role of p53 in limiting somatic cell reprogramming

    Institute of Scientific and Technical Information of China (English)

    Yan Liu; Ruben Hoya-Arias; Stephen D Nimer


    @@ The first successful generation of induced pluripotent stem(iPS)cells from somatic cells was accomplished by introducing four genes into the cell,0ct3/4,Sox2,Klf4,and c-myc [1].While a tour-de-force,this approach to iPS cell generation is inefficient,and unlikely to be directly translated into therapeutic use since it involves the use of retroviruses to introduce these genes into the cell.Subsequent studies have used non-integrating genetic elements,chemical compounds,or proteins rather than DNA to bypass concerns about retroviral insertional mutagenesis [2-5].

  14. Two-dimensional diffusion limited system for cell growth

    Energy Technology Data Exchange (ETDEWEB)

    Hlatky, L.


    A new cell system, the ''sandwich'' system, was developed to supplement multicellular spheroids as tumor analogues. Sandwiches allow new experimental approaches to questions of diffusion, cell cycle effects and radiation resistance in tumors. In this thesis the method for setting up sandwiches is described both theoretically and experimentally followed by its use in x-ray irradiation studies. In the sandwich system, cells are grown in a narrow gap between two glass slides. Where nutrients and waste products can move into or out of the local environment of the cells only by diffusing through the narrow gap between the slides. Due to the competition between cells, self-created gradients of nutrients and metabolic products are set up resulting in a layer of cells which resembles a living spheroid cross section. Unlike the cells of the spheroid, however, cells in all regions of the sandwich are visible. Therefore, the relative sizes of the regions and their time-dependent growth can be monitored visually without fixation or sectioning. The oxygen and nutrient gradients can be ''turned off'' at any time without disrupting the spatial arrangement of the cells by removing the top slide of the assembly and subsequently turned back on if desired. Removal of the top slide also provides access to all the cells, including those near the necrotic center, of the sandwich. The cells can then be removed for analysis outside the sandwich system. 61 refs., 17 figs.

  15. Adult stem cell transplantation in stroke: its limitations and prospects. (United States)

    Roh, Jae-Kyu; Jung, Keun-Hwa; Chu, Kon


    A growing number of studies have demonstrated stem cell-based therapy provides a feasible, realistic approach to the restoration of lost brain function after stroke. Moreover, adult stem cells may provide more appropriate clinical strategies. Leading candidate sources include bone marrow, peripheral blood, adipose tissue, skeletal muscle, and olfactory mucosa, which act as central repositories for multipotent stem cells that can repopulate neural tissues. The medical society is currently enthusiastic concerning the clinical applications of autologous adult stem cells in stroke, based on promising results obtained during experimental studies and initial clinical trials. However, before embracing clinical applications, several essential precautions must be properly addressed. For example, the regenerative potentials of adult stem cells decline with age, and stem cells isolated from aged patients may retain dysfunctional characteristics. Are the natures and amounts of available autologous cells appropriate for therapeutic application in stroke? Do transplanted cells remain functional in the diseased brain, and if so what are the optimal injection routes, cell doses, and timings? Thus, we believe that success in future clinical trials will depend on careful investigation at the experimental level, to allow us to understand not only the practicalities of stem cell use, but also the underlying biological principles involved. Here, we review the advantages and disadvantages of the different adult stem cell sources and discuss the challenges that must be negotiated to achieve transplantation success.

  16. Identifying thyroid stem/progenitor cells: advances and limitations. (United States)

    Fierabracci, Alessandra


    Continuing advances in stem cell science have prompted researchers to envisage the potential application of stem cells for the management of several debilitating disorders, thus raising the expectations of transplant clinicians. In particular, in order to find a source of adult stem cells alternative to embryonic stem cells (ESCs) for the exploration of novel strategies in regenerative medicine, researchers have attempted to identify and characterise adult stem/progenitor cells resident in compact organs, since these populations appear to be responsible for physiological tissue renewal and regeneration after injury. In particular, recent studies have also reported evidence for the existence of adult stem/progenitor cell populations in both mouse and human thyroids. Here, I provide a review of published findings about ESC lines capable of generating thyroid follicular cells, thyroid somatic stem cells and cancer stem cells within the thyroid. The three subjects are analysed by also considering the criticism recently raised against their existence and potential utility. I comment specifically on the significance of resident thyroid stem cells in the developmental biology of the gland and their putative role in the pathogenesis of thyroid disorders and on the protocols employed for their identification. I finally provide my opinion on whether from basic science results obtained to date it is possible to extrapolate any convincing basic for future treatment of thyroid disorders.

  17. 类胰蛋白酶和类糜蛋白酶表达在过敏反应死亡与冠心病猝死者组织中的表达%Expression of tryptase and chymase in anaphylactic death and sudden coronary death and their significance in forensic medicine

    Institute of Scientific and Technical Information of China (English)

    付立平; 张付瑶; 王涛; 王慧君


    Objective To investigate the relationship between the expression of tryptase and chymase with anaphylactic death and sudden coronary death (SCD) , and their diagnostic significanpe in forensic pathology. Methods Autopsy heart and lung samples (n = 70) collected during 2008 -2011 in our department were divided into 4 groups. Group A (20cases) died of sudden death with coronary heart disease (SCD) ;group B (20 cases) ,non -sudden death with coronary heart disease;group C (lOcases) died of anaphylaxis sudden death; Group group D:20 cases died of any cause without atherosclerosis. Tryptase and chymase were detected by immunohistochemistry ( SP method) and image analysis. Results The OD values of trypase in the ischemic myocardium and lung tissue were significantly higher in SCD, CHD, sudden anaphylactic death groups than that in the control group, with statistically significant differences among the groups (P 0. 05). Conclusions Chymase protein level is increased in sudden coronary death (SCD) and anaphylactic death patients. However, chymase only accounts for 3% of the total protein in mast cells, and the expression of this protease is not sufficient as an evidence to identify anaphylactic death and coronary heart disease death. Tryptase is increased in the heart and lung of sudden coronary death ( SCD) and anaphylactic death patients, and could be used as an important reference for medical identification of sudden death from anaphylaxis and coronary heart disease.%目的 探讨类胰蛋白酶( tryptase)和类糜蛋白酶(chymase)在过敏反应死亡中表达及其与过敏反应死亡和冠心病猝死的关系,为过敏反应死亡的病理诊断和法医学鉴定提供新的形态学依据.方法 从本教研室2008-2011年尸检档案中挑选病例70例,并搜集其原始档案资料、福尔马林固定包埋的心脏及肺脏蜡块,复阅HE切片.分为四组:A组:冠心病猝死(SCD,20例);B组:冠心病非猝死者(CHD,20例);C组:过敏性猝死(10例)

  18. Stem cells in tooth tissue regeneration--challenges and limitations. (United States)

    Inanç, Bülend; Elçin, Y Murat


    The accelerated pace of research in the stem cell field in recent decades and the accumulated body of knowledge has spurred the interest in potential clinical applications of stem cells in all branches of medicine including regenerative dentistry. In humans, embryonic and adult stem cells are two major groups of cells that can serve as a donor source in tissue engineering strategies based on ex-vivo cellular expansion. It has been shown that adult stem cell populations are present in all examined living tissues of the organism, thus being a crucial source of tissue homeostasis and regeneration, and offering a target population for in situ stimulation of extensive tissue regeneration. Experimental findings indicate that in the complex structure of the tooth organ, both periodontal and endodontic tissues harbour adult stem cells with characteristics peculiar to early stages of cellular differentiation. Myriad of strategies incorporating both embryonic and adult stem cells for the regeneration of a particular tooth structure or the whole teeth were proposed; however their successful application to solve real problems encountered in the clinical practice of dentistry remains an elusive and challenging objective.

  19. Safety Limitations Associated with Commercial 18650 Lithium-ion Cells (United States)

    Jeevarajan, Judith A.


    In the past decade, NASA-JSC battery group has carried out several tests on the safety of li-ion cells, modules and battery packs. The hazards associated with using commercial li-ion cells in high voltage and high capacity batteries have been determined to be different from those associated with the use of the same cells in low voltage, low capacity packs (less than 15 V and 60 Wh). Tests carried out included overcharge, overdischarge, external and internal short circuits with destructive physical analysis included in most cases. Chemical analysis, X-rays and in some cases CT scans were used for post-test analysis.

  20. Peripheral blood stem cell harvest in patients with limited stage small-cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Katakami, Nobuyuki; Takakura, Shunji; Fujii, Hiroshi; Nishimura, Takashi; Umeda, Bunichi [Kobe City General Hospital (Japan)


    Chemotherapy plus granulocyte colony-stimulating factor (G-CSF) induced mobilization of peripheral blood stem cells (PBSC) was performed in patients with limited stage small-cell lung cancer. Chemotherapy consisted of cisplatin/etoposide or cisplatin/adriamycin/etoposide. The amounts of CD34 positive cells and granulocyte-macrophage colony forming units (CFU-GM) collected during 2-3 courses of apheresis were 3.1{+-}2.9 x 10{sup 6}/kg (n=10) and 3.1{+-}1.5 x 10{sup 5}/kg (n=8) , respectively. Adequate amounts of PBSC were also harvested even in patients treated with concurrent chemoradiotherapy. Eight patients were successfully treated with high-dose chemotherapy consisting of ifosfamide, carboplatin and etoposide with PBSC transfusion. The patients'-bone marrow reconstruction was rapid and no treatment-related death was observed. (author)

  1. Growth-limiting role of endothelial cells in endoderm development. (United States)

    Sand, Fredrik Wolfhagen; Hörnblad, Andreas; Johansson, Jenny K; Lorén, Christina; Edsbagge, Josefina; Ståhlberg, Anders; Magenheim, Judith; Ilovich, Ohad; Mishani, Eyal; Dor, Yuval; Ahlgren, Ulf; Semb, Henrik


    Endoderm development is dependent on inductive signals from different structures in close vicinity, including the notochord, lateral plate mesoderm and endothelial cells. Recently, we demonstrated that a functional vascular system is necessary for proper pancreas development, and that sphingosine-1-phosphate (S1P) exhibits the traits of a blood vessel-derived molecule involved in early pancreas morphogenesis. To examine whether S1P(1)-signaling plays a more general role in endoderm development, S1P(1)-deficient mice were analyzed. S1P(1) ablation results in compromised growth of several foregut-derived organs, including the stomach, dorsal and ventral pancreas and liver. Within the developing pancreas the reduction in organ size was due to deficient proliferation of Pdx1(+) pancreatic progenitors, whereas endocrine cell differentiation was unaffected. Ablation of endothelial cells in vitro did not mimic the S1P(1) phenotype, instead, increased organ size and hyperbranching were observed. Consistent with a negative role for endothelial cells in endoderm organ expansion, excessive vasculature was discovered in S1P(1)-deficient embryos. Altogether, our results show that endothelial cell hyperplasia negatively influences organ development in several foregut-derived organs.

  2. Double expression of CD34 and CD117 on bone marrow progenitors is a hallmark of the development of functional mast cell of Callithrix jacchus (common marmoset). (United States)

    Nunomura, Satoshi; Shimada, Shin; Kametani, Yoshie; Yamada, Yuko; Yoshioka, Mino; Suemizu, Hiroshi; Ozawa, Manabu; Itoh, Toshio; Kono, Azumi; Suzuki, Ryuji; Tani, Kenzaburo; Ando, Kiyoshi; Yagita, Hideo; Ra, Chisei; Habu, Sonoko; Satake, Masanobu; Sasaki, Erika


    Mast cells (MCs) are developed from hematopoietic progenitor cells and play an important role in inflammation. Study of the kinetics of development and accumulation of primate MC in vivo is crucial for the control of human inflammatory diseases, as evolution of the immune system is quite rapid and inflammation including MC response is considered to be different between mouse and human. In the present study, we examined the development of MC from hematopoietic progenitors of Callithrix jacchus (common marmoset), an experimental animal of nonhuman primates. Bone marrow cells were fractionated for the expression of CD34 and CD117 by cell sorting. MCs were developed in vitro or by transplanting the cells to NOD/SCID/IL-2γc knockout (NOG) mice. In vitro culture of CD34(+)CD117(+) (double positive, DP) cells with stem cell factor could generate high-affinity Fc epsilon receptor (FcεR)-expressing CD117(+) cells with typical granules. The developed MC released β-hexosaminidase and produced leukotriene C(4) after the stimulation of FcεRI. Transplantation of DP cells gave rise to a marked expansion of CD34(-)CD45(+)CD117(+)FcεR(+) cells in NOG mice. They expressed transcripts encoding chymase 1 and tryptase β. Differentiation of CD34(-)CD117(+) cells to MCs was relatively limited compared with the DP cells, similarly to human MCs. These results suggest that this marmoset system provides a good model for human MC development.

  3. Surgery in limited stage small cell lung cancer

    DEFF Research Database (Denmark)

    Lassen, U; Hansen, H H


    The role of surgery in small cell lung cancer (SCLC) is controversial. Surgery has several potential advantages because it may reduce the frequency of local relapses, it does not impede the intensity of chemotherapy, it does not affect the bone marrow, and surgical staging may be of prognostic...

  4. Association of mast cell-derived VEGF and proteases in Dengue shock syndrome.

    Directory of Open Access Journals (Sweden)

    Takahisa Furuta

    Full Text Available BACKGROUND: Recent in-vitro studies have suggested that mast cells are involved in Dengue virus infection. To clarify the role of mast cells in the development of clinical Dengue fever, we compared the plasma levels of several mast cell-derived mediators (vascular endothelial cell growth factor [VEGF], soluble VEGF receptors [sVEGFRs], tryptase, and chymase and -related cytokines (IL-4, -9, and -17 between patients with differing severity of Dengue fever and healthy controls. METHODOLOGY/PRINCIPAL FINDINGS: The study was performed at Children's Hospital No. 2, Ho Chi Minh City, and Vinh Long Province Hospital, Vietnam from 2002 to 2005. Study patients included 103 with Dengue fever (DF, Dengue hemorrhagic fever (DHF, and Dengue shock syndrome (DSS, as diagnosed by the World Health Organization criteria. There were 189 healthy subjects, and 19 febrile illness patients of the same Kinh ethnicity. The levels of mast cell-derived mediators and -related cytokines in plasma were measured by ELISA. VEGF and sVEGFR-1 levels were significantly increased in DHF and DSS compared with those of DF and controls, whereas sVEGFR-2 levels were significantly decreased in DHF and DSS. Significant increases in tryptase and chymase levels, which were accompanied by high IL-9 and -17 concentrations, were detected in DHF and DSS patients. By day 4 of admission, VEGF, sVEGFRs, and proteases levels had returned to similar levels as DF and controls. In-vitro VEGF production by mast cells was examined in KU812 and HMC-1 cells, and was found to be highest when the cells were inoculated with Dengue virus and human Dengue virus-immune serum in the presence of IL-9. CONCLUSIONS: As mast cells are an important source of VEGF, tryptase, and chymase, our findings suggest that mast cell activation and mast cell-derived mediators participate in the development of DHF. The two proteases, particularly chymase, might serve as good predictive markers of Dengue disease severity.

  5. Fundamental electronic mechanisms limiting the performance of solar cells (United States)

    Lindholm, F. A.; Sah, C.-T.


    Attention is focused on distortion in the energy band, and carrier recombination and generation rates (lifetimes), as the two dominant mechanisms. Spatial dependences associated with these two mechanisms, in the direction normal to the surface illuminated by the sun and in the direction tangential to that surface, are also emphasized as crucial factors in governing the efficiency of solar cells. Electronic parameters for the set of differential equations characterizing transport, recombination, and generation of carriers, and interband and band-bound transition rates, are studied.

  6. Light trapping in solar cells at the extreme coupling limit

    CERN Document Server

    Naqavi, Ali; Battaglia, Corsin; Herzig, Hans Peter; Ballif, Christophe


    We calculate the maximal absorption enhancement obtainable by guided mode excitation in a weakly absorbing dielectric slab over wide wavelength ranges. The slab mimics thin film silicon solar cells in the low absorption regime. We consider simultaneously wavelength-scale periodicity of the texture, small thickness of the film, modal properties of the guided waves and their confinement to the film. Also we investigate the effect of the incident angle on the absorption enhancement. Our calculations provide tighter bounds for the absorption enhancement but still significant improvement is possible. Our explanation of the absorption enhancement can help better exploitation of the guided modes in thin film devices.

  7. Sub-diffraction limited quantum imaging of a living cell

    CERN Document Server

    Taylor, Michael A; Daria, Vincent; Knittel, Joachim; Hage, Boris; Bachor, Hans-A; Bowen, Warwick P


    Quantum techniques allow the resolution constraints of classical imaging to be overcome, and are expected to have important applications in biology. We report the first demonstration of sub-diffraction limited quantum imaging in biology. Naturally occurring lipid granules of approximately 300nm diameter are used to image the local mechanical properties of the cellular cytoplasm, with spatial resolution enabled by thermal diffusion. Spatial structure is resolved at length scales down to 10nm. Our results confirm the longstanding prediction that use of quantum correlated light can enhance spatial resolution in biology, allowing a 14% enhancement over that achievable with coherent light. Combined with state-of-the-art sources of quantum correlated light, this technique provides a path towards an order of magnitude improvement in resolution over similar classical imaging techniques.

  8. Legal Limitations of Researching and Using the Stem Cells

    Directory of Open Access Journals (Sweden)

    Rustin-Petru CIASC


    Full Text Available The importance of research in view of using stem cells for scientific and medical purposes must be regulated in a clear and, to the degree possible, single manner, at European and world level. Beginning with this obvious necessity, this article attempts to review the relevant provisions in the domestic legislation, while supplying the required appreciations and criticism. In the end, it reaches the idea, also upon replying on some compared law elements, that not only some legislative modifications or adaptations are imposed, in connection to the normative acts in force, but particularly the creation of a complete and complex legislative framework. It must cover the existence of all practical situations and regulate the scientific research activity in this domain, without ignoring at any time the inviolability of human dignity and acknowledging the right of integrity of the person’s body and mind.

  9. Limited gene expression variation in human embryonic stem cell and induced pluripotent stem cell-derived endothelial cells. (United States)

    White, Mark P; Rufaihah, Abdul J; Liu, Lei; Ghebremariam, Yohannes T; Ivey, Kathryn N; Cooke, John P; Srivastava, Deepak


    Recent evidence suggests human embryonic stem cell (hESC) and induced pluripotent stem (iPS) cell lines have differences in their epigenetic marks and transcriptomes, yet the impact of these differences on subsequent terminally differentiated cells is less well understood. Comparison of purified, homogeneous populations of somatic cells derived from multiple independent human iPS and ES lines will be required to address this critical question. Here, we report a differentiation protocol based on embryonic development that consistently yields large numbers of endothelial cells (ECs) derived from multiple hESCs or iPS cells. Mesoderm differentiation of embryoid bodies was maximized, and defined growth factors were used to generate KDR(+) EC progenitors. Magnetic purification of a KDR(+) progenitor subpopulation resulted in an expanding, homogeneous pool of ECs that expressed EC markers and had functional properties of ECs. Comparison of the transcriptomes revealed limited gene expression variability between multiple lines of human iPS-derived ECs or between lines of ES- and iPS-derived ECs. These results demonstrate a method to generate large numbers of pure human EC progenitors and differentiated ECs from pluripotent stem cells and suggest individual lineages derived from human iPS cells may have significantly less variance than their pluripotent founders.

  10. Modulation of histamine release from human colon mast cells by protease inhibitors

    Institute of Scientific and Technical Information of China (English)

    Shao-Heng He; Hua Xie


    AIM: To investigate the ability of protease inhibitors to modulate histamine release from human colon mast cells.METHODS: Enzymatically dispersed cells from human colon were challenged with anti-IgE or calcium ionophore A23187 in the absence or presence of tryptase and chymase inhibitors, and histamine release was determined.RESULTS: IgE dependent histamine release from colon mast cells was inhibited by up to approximately 37%, 26% and 36.8% by chymase inhibitors Z-Ile-Glu-Pro-Phe-CO2Me (ZIGPFM), N-Tosyl-L-phenylalanyl-chloromethyl ketone (TPCK), and α1-antitrypsin, respectively. Similarly, inhibitors of tryptase leupeptin, N-tosyl-L-lysine chloromethyl ketone (TLCK), lactoferrin and protamine were also able to inhibit anti-IgE induced histamine release by a maximum of some 48%, 37%, 40% and 34%, respectively. Preincubation of these inhibitors with cells for 20 min before challenged with anti-IgE had small effect on the inhibitory actions of these inhibitors on colon mast cells. A specific inhibitor of aminopeptidase amastatin had no effect on anti-IgE induced histamine release. The significant inhibition of calcium ionophore induced histamine release was also observed with the inhibitors of tryptase and chymase examined. Apart from leupeptin and protamine, the inhibitors tested by themselves did not stimulate colon mast cells.CONCLUSION: It was demonstrated that both tryptase and chymase inhibitors could inhibit IgE dependent and calcium ionophore induced histamine release from dispersed colon mast cells in a concentration dependent of manner, which suggest that they are likely to be developed as a novel class of anti-inflammatory drugs to treat chronic of colitis in man.

  11. Haplotype-based banking of human pluripotent stem cells for transplantation: potential and limitations. (United States)

    Zimmermann, Anna; Preynat-Seauve, Olivier; Tiercy, Jean-Marie; Krause, Karl-Heinz; Villard, Jean


    High expectations surround the area of stem cells therapeutics. However, the cells' source-adult or embryonic-and the cells' origin-patient-derived autologous or healthy donor genetically unrelated-remain subjects of debate. Autologous origins have the advantage of a theoretical absence of immune rejection by the recipient. However, this approach has several limitations with regard to the disease of the recipient and to potential problems with the generation, expansion, and manipulation of autologous induced pluripotent stem cells (iPS cells) preparation. An alternative to using autologous cells is the establishment of a bank of well-characterized adult cells that would be used to generate iPS cells and their derivatives. In the context of transplantation, such cells would come from genetically unrelated donors and the immune system of the recipient would reject the graft without immunosuppressive therapy. To minimize the risk of rejection, human leukocyte antigen (HLA) compatibility is certainly the best option, and the establishment of an HLA-organized bank would mean having a limited number of stem cells that would be sufficient for a large number of recipients. The concept of haplobanking with HLA homozygous cell lines would also limit the number of HLA mismatches, but such an approach will not necessarily be less immunogenic in terms of selection criteria, because of the limited number of HLA-compatible loci and the level of HLA typing resolution.

  12. High-throughput screening for hamster chymase 2 inhibitors%仓鼠糜酶2抑制剂高通量筛选模型的建立及其应用

    Institute of Scientific and Technical Information of China (English)

    王守宝; 竺晓鸣; 高峰; 庞晓斌; 杜冠华


    本研究拟建立重组仓鼠糜酶2 (chymase 2)抑制剂的体外高通量筛选模型,寻找新型的糜酶2抑制剂.首先,利用大肠杆菌表达、制备成熟的重组仓鼠糜酶2蛋白,以384孔微板为媒介,建立基于荧光方法测定酶活性的抑制剂筛选模型,结果表明所建立的糜酶2抑制剂高通量筛选模型具有灵敏、稳定、重复性好的特点(Z′=0.84).利用建立的模型对40 080种样品(包括28 060种化合物和12 020种天然产物提取物)进行抑制活性筛选,取抑制率大于90%的613种样品进行复筛.最终确定化合物J16647和J16648具有较强的抑制活性,其IC50值分别为0.823和0.690 μmol·L-1.%To screen potential hamster chymase 2 inhibitors, a high-throughput screening (HTS) model was established. Recombinant hamster chymase 2 with active form was cloned and expressed in E. Coli. The HTS model with total volume of 50 L in 384-well microplate was based on fluorescence analysis and was proved sensitive as well as specific (Z' = 0.84). A total of 40 080 samples (including 28 060 compounds and 12 020 natural products) were screened, and 613 samples with inhibition greater than 90% were selected for further rescreening. Finally, compounds J16647 and J16648 were identified with high inhibitory activity on chymase 2, and whose IC50 values were 0.823 and 0.690 μmol·L-1, respectively.

  13. Silicon solar cells reaching the efficiency limits: from simple to complex modelling (United States)

    Kowalczewski, Piotr; Redorici, Lisa; Bozzola, Angelo; Andreani, Lucio Claudio


    Numerical modelling is pivotal in the development of high efficiency solar cells. In this contribution we present different approaches to model the solar cell performance: the diode equation, a generalization of the well-known Hovel model, and a complete device modelling. In all three approaches we implement a Lambertian light trapping, which is often considered as a benchmark for the optical design of solar cells. We quantify the range of parameters for which all three approaches give the same results, and highlight the advantages and limitations of different models. Using these methods we calculate the efficiency limits of single-junction crystalline silicon solar cells in a wide range of cell thickness. We find that silicon solar cells close to the efficiency limits operate in the high-injection (rather than in the low-injection) regime. In such a regime, surface recombination can have an unexpectedly large effect on cells with the absorber thickness lower than a few tens of microns. Finally, we calculate the limiting efficiency of tandem silicon-perovskite solar cells, and we determine the optimal thickness of the bottom silicon cell for different band gaps of the perovskite material.

  14. Effect of lipopolysaccharide (LPS and peptidoglycan (PGN on human mast cell numbers, cytokine production, and protease composition

    Directory of Open Access Journals (Sweden)

    Wu Yalin


    Full Text Available Abstract Background Human mast cell (HuMC maturation occurs in tissues interfacing with the external environment, exposing both mast cell progenitors and mature mast cells, to bacteria and their products. It is unknown, however, whether long- or short-term exposure to bacteria-derived toll-like receptor (TLR ligands, such as lipopolysaccharide (LPS or peptidoglycan (PGN, influences HuMC biology. Results Over 6 wks of culture, LPS had minimal effect on HuMC numbers but increased CD117, tryptase and chymase expression. PGN inhibited HuMC development. For mature mast cells, LPS in the presence of rhSCF (10 ng/ml increased CD117, tryptase, chymase and carboxypeptidase expression, primarily in CD117low HuMC. LPS decreased FcεRI expression and β-hexosaminidase release; but had no effect on LTC4 and PGD2 production. PGN reduced HuMC numbers; and CD117 and tryptase expression. IL-1β and IL-6 (in addition to IL-8 and IL-12 were detected in short-term culture supernatants of LPS treated cells, and reproduced the increases in CD117, tryptase, chymase, and carboxypeptidase expression observed in the presence of LPS. Comparative studies with mouse bone marrow-derived mast cells from wild type, but not TLR4 knockout mice, showed increases in mRNA of mouse mast cell chymases MMCP-1, MMCP-2 and MMCP-4. Conclusion PGN inhibits HuMC growth, while LPS exerts its primary effects on mature HuMC by altering cytokine production and protease composition, particularly at low concentrations of SCF. These data demonstrate the ability of bacterial products to alter HuMC mediator production, granular content, and number which may be particularly relevant at mucosal sites where HuMC are exposed to these products.

  15. Dietary antigens limit mucosal immunity by inducing regulatory T cells in the small intestine. (United States)

    Kim, Kwang Soon; Hong, Sung-Wook; Han, Daehee; Yi, Jaeu; Jung, Jisun; Yang, Bo-Gie; Lee, Jun Young; Lee, Minji; Surh, Charles D


    Dietary antigens are normally rendered nonimmunogenic through a poorly understood "oral tolerance" mechanism that involves immunosuppressive regulatory T (Treg) cells, especially Treg cells induced from conventional T cells in the periphery (pTreg cells). Although orally introducing nominal protein antigens is known to induce such pTreg cells, whether a typical diet induces a population of pTreg cells under normal conditions thus far has been unknown. By using germ-free mice raised and bred on an elemental diet devoid of dietary antigens, we demonstrated that under normal conditions, the vast majority of the small intestinal pTreg cells are induced by dietary antigens from solid foods. Moreover, these pTreg cells have a limited life span, are distinguishable from microbiota-induced pTreg cells, and repress underlying strong immunity to ingested protein antigens.

  16. Epithelial Cell Coculture Models for Studying Infectious Diseases: Benefits and Limitations

    Directory of Open Access Journals (Sweden)

    Benjamin L. Duell


    Full Text Available Countless in vitro cell culture models based on the use of epithelial cell types of single lineages have been characterized and have provided insight into the mechanisms of infection for various microbial pathogens. Diverse culture models based on disease-relevant mucosal epithelial cell types derived from gastrointestinal, genitourinary, and pulmonary organ systems have delineated many key host-pathogen interactions that underlie viral, parasitic, and bacterial disease pathogenesis. An alternative to single lineage epithelial cell monoculture, which offers more flexibility and can overcome some of the limitations of epithelial cell culture models based on only single cell types, is coculture of epithelial cells with other host cell types. Various coculture models have been described, which incorporate epithelial cell types in culture combination with a wide range of other cell types including neutrophils, eosinophils, monocytes, and lymphocytes. This paper will summarize current models of epithelial cell coculture and will discuss the benefits and limitations of epithelial cell coculture for studying host-pathogen dynamics in infectious diseases.

  17. Approaching the Lambertian limit in randomly textured thin-film solar cells. (United States)

    Fahr, Stephan; Kirchartz, Thomas; Rockstuhl, Carsten; Lederer, Falk


    The Lambertian limit for solar cells is a benchmark for evaluating their efficiency. It has been shown that the performance of either extremely thick or extremely thin solar cells can be driven close to this limit by using an appropriate photon management. Here we show that this is likewise possible for realistic, practically relevant thin-film solar cells based on amorphous silicon. Most importantly, we achieve this goal by relying on random textures already incorporated into state-of-the-art superstrates; with the only subtlety that their topology has to be downscaled to typical feature sizes of about 100 nm.

  18. Lack of increased expression of cell surface markers for circulating fibrocyte progenitors in limited scleroderma. (United States)

    Russo, R; Medbury, H; Guiffre, A; Englert, H; Manolios, N


    The aetiology and pathogenesis of scleroderma is incompletely understood. Recently, a cell called the fibrocyte has been shown to be derived from circulating monocytes with the ability to produce collagen. The aim of this study was to evaluate differences in the cell surface characteristics of circulating fibrocyte progenitors (monocytes) in patients with limited scleroderma compared to controls. A case-control study was performed in eight patients with limited scleroderma, which were matched with eight controls. Three-colour flow cytometry was used to assess the relative expression of cell surface markers. Statistical analysis then compared the relative expression between the two groups. In this preliminary study, there were no significant differences in the expression of circulating monocyte surface molecules involved with cell transformation, function, or migration presumed to give rise to fibrocytes, in a population of patients with limited scleroderma. Various explanations for the results are discussed.

  19. Circadian rhythms in the cell cycle and biomass composition of Neochloris oleoabundans under nitrogen limitation. (United States)

    de Winter, Lenneke; Schepers, Lutz W; Cuaresma, Maria; Barbosa, Maria J; Martens, Dirk E; Wijffels, René H


    The circadian clock schedules processes in microalgae cells at suitable times in the day/night cycle. To gain knowledge about these biological time schedules, Neochloris oleoabundans was grown under constant light conditions and nitrogen limitation. Under these constant conditions, the only variable was the circadian clock. The results were compared to previous work done under nitrogen-replete conditions, in order to determine the effect of N-limitation on circadian rhythms in the cell cycle and biomass composition of N. oleoabundans. The circadian clock was not affected by nitrogen-limitation, and cell division was timed in the natural night, despite of constant light conditions. However, because of nitrogen-limitation, not the entire population was able to divide every day. Two subpopulations were observed, which divided alternately every other day. This caused oscillations in biomass yield and composition. Starch and total fatty acids (TFA) were accumulated during the day. Also, fatty acid composition changed during the cell cycle. Neutral lipids were built up during the day, especially in cells that were arrested in their cell cycle (G2 and G3). These findings give insight in the influence of circadian rhythms on the cell cycle and biomass composition.

  20. Nano-photonic light trapping near the Lambertian limit in organic solar cell architectures. (United States)

    Biswas, Rana; Timmons, Erik


    A critical step to achieving higher efficiency solar cells is the broad band harvesting of solar photons. Although considerable progress has recently been achieved in improving the power conversion efficiency of organic solar cells, these cells still do not absorb upto ~50% of the solar spectrum. We have designed and developed an organic solar cell architecture that can boost the absorption of photons by 40% and the photo-current by 50% for organic P3HT-PCBM absorber layers of typical device thicknesses. Our solar cell architecture is based on all layers of the solar cell being patterned in a conformal two-dimensionally periodic photonic crystal architecture. This results in very strong diffraction of photons- that increases the photon path length in the absorber layer, and plasmonic light concentration near the patterned organic-metal cathode interface. The absorption approaches the Lambertian limit. The simulations utilize a rigorous scattering matrix approach and provide bounds of the fundamental limits of nano-photonic light absorption in periodically textured organic solar cells. This solar cell architecture has the potential to increase the power conversion efficiency to 10% for single band gap organic solar cells utilizing long-wavelength absorbers.

  1. Design of coated standing nanowire array solar cell performing beyond the planar efficiency limits (United States)

    Zeng, Yang; Ye, Qinghao; Shen, Wenzhong


    The single standing nanowire (SNW) solar cells have been proven to perform beyond the planar efficiency limits in both open-circuit voltage and internal quantum efficiency due to the built-in concentration and the shifting of the absorption front. However, the expandability of these nano-scale units to a macro-scale photovoltaic device remains unsolved. The main difficulty lies in the simultaneous preservation of an effective built-in concentration in each unit cell and a broadband high absorption capability of their array. Here, we have provided a detailed theoretical guideline for realizing a macro-scale solar cell that performs furthest beyond the planar limits. The key lies in a complementary design between the light-trapping of the single SNWs and that of the photonic crystal slab formed by the array. By tuning the hybrid HE modes of the SNWs through the thickness of a coaxial dielectric coating, the optimized coated SNW array can sustain an absorption rate over 97.5% for a period as large as 425 nm, which, together with the inherited carrier extraction advantage, leads to a cell efficiency increment of 30% over the planar limit. This work has demonstrated the viability of a large-size solar cell that performs beyond the planar limits.

  2. The efficiency limit of CH3NH3PbI3 perovskite solar cells (United States)

    Sha, Wei E. I.; Ren, Xingang; Chen, Luzhou; Choy, Wallace C. H.


    With the consideration of photon recycling effect, the efficiency limit of methylammonium lead iodide (CH3NH3PbI3) perovskite solar cells is predicted by a detailed balance model. To obtain convincing predictions, both AM 1.5 spectrum of Sun and experimentally measured complex refractive index of perovskite material are employed in the detailed balance model. The roles of light trapping and angular restriction in improving the maximal output power of thin-film perovskite solar cells are also clarified. The efficiency limit of perovskite cells (without the angular restriction) is about 31%, which approaches to Shockley-Queisser limit (33%) achievable by gallium arsenide (GaAs) cells. Moreover, the Shockley-Queisser limit could be reached with a 200 nm-thick perovskite solar cell, through integrating a wavelength-dependent angular-restriction design with a textured light-trapping structure. Additionally, the influence of the trap-assisted nonradiative recombination on the device efficiency is investigated. The work is fundamentally important to high-performance perovskite photovoltaics.

  3. PU.1 Expression in T Follicular Helper Cells Limits CD40L-Dependent Germinal Center B Cell Development. (United States)

    Awe, Olufolakemi; Hufford, Matthew M; Wu, Hao; Pham, Duy; Chang, Hua-Chen; Jabeen, Rukhsana; Dent, Alexander L; Kaplan, Mark H


    PU.1 is an ETS family transcription factor that is important for the development of multiple hematopoietic cell lineages. Previous work demonstrated a critical role for PU.1 in promoting Th9 development and in limiting Th2 cytokine production. Whether PU.1 has functions in other Th lineages is not clear. In this study, we examined the effects of ectopic expression of PU.1 in CD4(+) T cells and observed decreased expression of genes involved with the function of T follicular helper (Tfh) cells, including Il21 and Tnfsf5 (encoding CD40L). T cells from conditional mutant mice that lack expression of PU.1 in T cells (Sfpi1(lck-/-)) demonstrated increased production of CD40L and IL-21 in vitro. Following adjuvant-dependent or adjuvant-independent immunization, we observed that Sfpi1(lck-/-) mice had increased numbers of Tfh cells, increased germinal center B cells (GCB cells), and increased Ab production in vivo. This correlated with increased expression of IL-21 and CD40L in Tfh cells from Sfpi1(lck-/-) mice compared with control mice. Finally, although blockade of IL-21 did not affect GCB cells in Sfpi1(lck-/-) mice, anti-CD40L treatment of immunized Sfpi1(lck-/-) mice decreased GCB cell numbers and Ag-specific Ig concentrations. Together, these data indicate an inhibitory role for PU.1 in the function of Tfh cells, germinal centers, and Tfh-dependent humoral immunity.

  4. The number of fetal nephron progenitor cells limits ureteric branching and adult nephron endowment. (United States)

    Cebrian, Cristina; Asai, Naoya; D'Agati, Vivette; Costantini, Frank


    Nephrons, the functional units of the kidney, develop from progenitor cells (cap mesenchyme [CM]) surrounding the epithelial ureteric bud (UB) tips. Reciprocal signaling between UB and CM induces nephrogenesis and UB branching. Although low nephron number is implicated in hypertension and renal disease, the mechanisms that determine nephron number are obscure. To test the importance of nephron progenitor cell number, we genetically ablated 40% of these cells, asking whether this would limit kidney size and nephron number or whether compensatory mechanisms would allow the developing organ to recover. The reduction in CM cell number decreased the rate of branching, which in turn allowed the number of CM cells per UB tip to normalize, revealing a self-correction mechanism. However, the retarded UB branching impaired kidney growth, leaving a permanent nephron deficit. Thus, the number of fetal nephron progenitor cells is an important determinant of nephron endowment, largely via its effect on UB branching.

  5. Examination of 1D Solar Cell Model Limitations Using 3D SPICE Modeling: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    McMahon, W. E.; Olson, J. M.; Geisz, J. F.; Friedman, D. J.


    To examine the limitations of one-dimensional (1D) solar cell modeling, 3D SPICE-based modeling is used to examine in detail the validity of the 1D assumptions as a function of sheet resistance for a model cell. The internal voltages and current densities produced by this modeling give additional insight into the differences between the 1D and 3D models.

  6. Mast cells and cancer: enemies or allies? (United States)

    Dyduch, Grzegorz; Kaczmarczyk, Karolina; Okoń, Krzysztof


    Mast cells are a component of cancer microenvironment the role of which is complex and poorly understood. Mast cells promote cancer growth by stimulation of neoangiogenesis, tissue remodeling and by modulation of the host immune response. The mediators of cancer promotion include protease-activated receptors, mitogen activated protein kinases, prostaglandins and histamine. Histamine may induce tumor proliferation and immunosuppression through H1 and H2 receptors, respectively. The mast cell-derived modulators of immune response include also interleukin 10 (IL-10), tumor necrosis factor α (TNF-α) and CD30L. Possibly stimulation of angiogenesis is the most important. Mast cells release potent proangiogenic factors such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), transforming growth factor β (TGF-β), TNF- α and IL-8, and mast cells' enzymes, like metaloproteinases (MMPs), tryptase and chymase participate in vessels' formation. The anti-cancer actions of mast cells include direct growth inhibition, immunologic stimulation, inhibition of apoptosis and decreased cell mobility; the mediators of these processes include chymase, tryptase, TNF-α, IL-1 and IL-6. The very same mediators may exert both pro- or anti-cancer effects depending on concentration, presence of cofactors or location of secreting cells. In fact, peri- and intra-tumoral mast cells may have dissimilar effects. Understanding of the role of mast cells in cancer could lead to improved prognostication and development of therapeutic methods targeting the mast cells.

  7. Categorical methods for the interpretation of RNA profiles as cell type evidence and their limitations

    NARCIS (Netherlands)

    J. de Zoete; J. Curran; M. Sjerps


    Existing methods for the interpretation of RNA profiles as evidence for the presence of certain cell types aim for making categorical statements. Such statements limit the possibility to report the associated uncertainty. From a statistical point of view, a probabilistic approach is a preferable cho

  8. Rgs13 constrains early B cell responses and limits germinal center sizes.

    Directory of Open Access Journals (Sweden)

    Il-Young Hwang

    Full Text Available Germinal centers (GCs are microanatomic structures that develop in secondary lymphoid organs in response to antigenic stimulation. Within GCs B cells clonally expand and their immunoglobulin genes undergo class switch recombination and somatic hypermutation. Transcriptional profiling has identified a number of genes that are prominently expressed in GC B cells. Among them is Rgs13, which encodes an RGS protein with a dual function. Its canonical function is to accelerate the intrinsic GTPase activity of heterotrimeric G-protein α subunits at the plasma membrane, thereby limiting heterotrimeric G-protein signaling. A unique, non-canonical function of RGS13 occurs following translocation to the nucleus, where it represses CREB transcriptional activity. The functional role of RGS13 in GC B cells is unknown. To create a surrogate marker for Rgs13 expression and a loss of function mutation, we inserted a GFP coding region into the Rgs13 genomic locus. Following immunization GFP expression rapidly increased in activated B cells, persisted in GC B cells, but declined in newly generated memory B and plasma cells. Intravital microscopy of the inguinal lymph node (LN of immunized mice revealed the rapid appearance of GFP(+ cells at LN interfollicular regions and along the T/B cell borders, and eventually within GCs. Analysis of WT, knock-in, and mixed chimeric mice indicated that RGS13 constrains extra-follicular plasma cell generation, GC size, and GC B cell numbers. Analysis of select cell cycle and GC specific genes disclosed an aberrant gene expression profile in the Rgs13 deficient GC B cells. These results indicate that RGS13, likely acting at cell membranes and in nuclei, helps coordinate key decision points during the expansion and differentiation of naive B cells.

  9. Radio-frequency Electrometry Using Rydberg Atoms in Vapor Cells: Towards the Shot Noise Limit (United States)

    Kumar, Santosh; Fan, Haoquan; Jahangiri, Akbar; Kuebler, Harald; Shaffer, James P.; 5. Physikalisches Institut, Universitat Stuttgart, Germany Collaboration


    Rydberg atoms are a promising candidate for radio frequency (RF) electric field sensing. Our method uses electromagnetically induced transparency with Rydberg atoms in vapor cells to read out the effect that the RF electric field has on the Rydberg atoms. The method has the potential for high sensitivity (pV cm-1 Hz- 1 / 2) and can be self-calibrated. Some of the main factors limiting the sensitivity of RF electric field sensing from reaching the shot noise limit are the residual Doppler effect and the sensitivity of the optical read-out using the probe laser. We present progress on overcoming the residual Doppler effect by using a new multi-photon scheme and reaching the shot noise detection limit using frequency modulated spectroscopy. Our experiments also show promise for studying quantum optical effects such as superradiance in vapor cells using Rydberg atoms. This work is supported by DARPA, ARO, and NRO.

  10. Analyzing Ca(2+) dynamics in intact epithelial cells using spatially limited flash photolysis. (United States)

    Almassy, Janos; Yule, David I


    The production of saliva by parotid acinar cells is stimulated by Ca(2+) activation of Cl(-) and K(+) channels located in the apical plasma membrane of these polarized cells. Here we describe a paradigm for the focal photorelease of either Ca(2+) or an inositol 1,4,5 trisphosphate (InsP(3)) analog. The protocol is designed to be useful for investigating subcellular Ca(2+) dynamics in polarized cells with minimal experimental intervention. Parotid acinar cells are loaded with cell-permeable versions of the caged precursors (NP-EGTA-AM or Ci-InsP(3)/PM). Photolysis is accomplished using a spatially limited, focused diode laser, but the experiment can be readily modified to whole-field photolysis using a xenon flash lamp.

  11. Prospects and Limitations of Using Endogenous Neural Stem Cells for Brain Regeneration

    Directory of Open Access Journals (Sweden)

    Kazunobu Sawamoto


    Full Text Available Neural stem cells (NSCs are capable of producing a variety of neural cell types, and are indispensable for the development of the mammalian brain. NSCs can be induced in vitro from pluripotent stem cells, including embryonic stem cells and induced-pluripotent stem cells. Although the transplantation of these exogenous NSCs is a potential strategy for improving presently untreatable neurological conditions, there are several obstacles to its implementation, including tumorigenic, immunological, and ethical problems. Recent studies have revealed that NSCs also reside in the adult brain. The endogenous NSCs are activated in response to disease or trauma, and produce new neurons and glia, suggesting they have the potential to regenerate damaged brain tissue while avoiding the above-mentioned problems. Here we present an overview of the possibility and limitations of using endogenous NSCs in regenerative medicine.

  12. Prospects and limitations of using endogenous neural stem cells for brain regeneration. (United States)

    Kaneko, Naoko; Kako, Eisuke; Sawamoto, Kazunobu


    Neural stem cells (NSCs) are capable of producing a variety of neural cell types, and are indispensable for the development of the mammalian brain. NSCs can be induced in vitro from pluripotent stem cells, including embryonic stem cells and induced-pluripotent stem cells. Although the transplantation of these exogenous NSCs is a potential strategy for improving presently untreatable neurological conditions, there are several obstacles to its implementation, including tumorigenic, immunological, and ethical problems. Recent studies have revealed that NSCs also reside in the adult brain. The endogenous NSCs are activated in response to disease or trauma, and produce new neurons and glia, suggesting they have the potential to regenerate damaged brain tissue while avoiding the above-mentioned problems. Here we present an overview of the possibility and limitations of using endogenous NSCs in regenerative medicine.

  13. Limitations of mRNA amplification from small-size cell samples

    Directory of Open Access Journals (Sweden)

    Myklebost Ola


    Full Text Available Abstract Background Global mRNA amplification has become a widely used approach to obtain gene expression profiles from limited material. An important concern is the reliable reflection of the starting material in the results obtained. This is especially important with extremely low quantities of input RNA where stochastic effects due to template dilution may be present. This aspect remains under-documented in the literature, as quantitative measures of data reliability are most often lacking. To address this issue, we examined the sensitivity levels of each transcript in 3 different cell sample sizes. ANOVA analysis was used to estimate the overall effects of reduced input RNA in our experimental design. In order to estimate the validity of decreasing sample sizes, we examined the sensitivity levels of each transcript by applying a novel model-based method, TransCount. Results From expression data, TransCount provided estimates of absolute transcript concentrations in each examined sample. The results from TransCount were used to calculate the Pearson correlation coefficient between transcript concentrations for different sample sizes. The correlations were clearly transcript copy number dependent. A critical level was observed where stochastic fluctuations became significant. The analysis allowed us to pinpoint the gene specific number of transcript templates that defined the limit of reliability with respect to number of cells from that particular source. In the sample amplifying from 1000 cells, transcripts expressed with at least 121 transcripts/cell were statistically reliable and for 250 cells, the limit was 1806 transcripts/cell. Above these thresholds, correlation between our data sets was at acceptable values for reliable interpretation. Conclusion These results imply that the reliability of any amplification experiment must be validated empirically to justify that any gene exists in sufficient quantity in the input material. This

  14. Systematic single-cell analysis of Pichia pastoris reveals secretory capacity limits productivity.

    Directory of Open Access Journals (Sweden)

    Kerry Routenberg Love

    Full Text Available Biopharmaceuticals represent the fastest growing sector of the global pharmaceutical industry. Cost-efficient production of these biologic drugs requires a robust host organism for generating high titers of protein during fermentation. Understanding key cellular processes that limit protein production and secretion is, therefore, essential for rational strain engineering. Here, with single-cell resolution, we systematically analysed the productivity of a series of Pichia pastoris strains that produce different proteins both constitutively and inducibly. We characterized each strain by qPCR, RT-qPCR, microengraving, and imaging cytometry. We then developed a simple mathematical model describing the flux of folded protein through the ER. This combination of single-cell measurements and computational modelling shows that protein trafficking through the secretory machinery is often the rate-limiting step in single-cell production, and strategies to enhance the overall capacity of protein secretion within hosts for the production of heterologous proteins may improve productivity.

  15. Asymptotic diffusion limit of cell temperature discretisation schemes for thermal radiation transport

    Energy Technology Data Exchange (ETDEWEB)

    Smedley-Stevenson, Richard P., E-mail: [AWE PLC, Aldermaston, Reading, Berkshire, RG7 4PR (United Kingdom); Department of Earth Science and Engineering, Imperial College London, SW7 2AZ (United Kingdom); McClarren, Ryan G., E-mail: [Department of Nuclear Engineering, Texas A & M University, College Station, TX 77843-3133 (United States)


    This paper attempts to unify the asymptotic diffusion limit analysis of thermal radiation transport schemes, for a linear-discontinuous representation of the material temperature reconstructed from cell centred temperature unknowns, in a process known as ‘source tilting’. The asymptotic limits of both Monte Carlo (continuous in space) and deterministic approaches (based on linear-discontinuous finite elements) for solving the transport equation are investigated in slab geometry. The resulting discrete diffusion equations are found to have nonphysical terms that are proportional to any cell-edge discontinuity in the temperature representation. Based on this analysis it is possible to design accurate schemes for representing the material temperature, for coupling thermal radiation transport codes to a cell centred representation of internal energy favoured by ALE (arbitrary Lagrange–Eulerian) hydrodynamics schemes.

  16. Tension-oriented cell divisions limit anisotropic tissue tension in epithelial spreading during zebrafish epiboly. (United States)

    Campinho, Pedro; Behrndt, Martin; Ranft, Jonas; Risler, Thomas; Minc, Nicolas; Heisenberg, Carl-Philipp


    Epithelial spreading is a common and fundamental aspect of various developmental and disease-related processes such as epithelial closure and wound healing. A key challenge for epithelial tissues undergoing spreading is to increase their surface area without disrupting epithelial integrity. Here we show that orienting cell divisions by tension constitutes an efficient mechanism by which the enveloping cell layer (EVL) releases anisotropic tension while undergoing spreading during zebrafish epiboly. The control of EVL cell-division orientation by tension involves cell elongation and requires myosin II activity to align the mitotic spindle with the main tension axis. We also found that in the absence of tension-oriented cell divisions and in the presence of increased tissue tension, EVL cells undergo ectopic fusions, suggesting that the reduction of tension anisotropy by oriented cell divisions is required to prevent EVL cells from fusing. We conclude that cell-division orientation by tension constitutes a key mechanism for limiting tension anisotropy and thus promoting tissue spreading during EVL epiboly.

  17. Limits to anaerobic energy and cytosolic concentration in the living cell (United States)

    Paglietti, A.


    For many physical systems at any given temperature, the set of all states where the system's free energy reaches its largest value can be determined from the system's constitutive equations of internal energy and entropy, once a state of that set is known. Such an approach is fraught with complications when applied to a living cell, because the cell's cytosol contains thousands of solutes, and thus thousands of state variables, which makes determination of its state impractical. We show here that, when looking for the maximum energy that the cytosol can store and release, detailed information on cytosol composition is redundant. Compatibility with cell's life requires that a single variable that represents the overall concentration of cytosol solutes must fall between defined limits, which can be determined by dehydrating and overhydrating the cell to its maximum capacity. The same limits are shown to determine, in particular, the maximum amount of free energy that a cell can supply in fast anaerobic processes, starting from any given initial state. For a typical skeletal muscle in normal physiological conditions this energy, i.e., the maximum anaerobic capacity to do work, is calculated to be about 960 J per kg of muscular mass. Such energy decreases as the overall concentration of solutes in the cytosol is increased. Similar results apply to any kind of cell. They provide an essential tool to understand and control the macroscopic response of single cells and multicellular cellular tissues alike. The applications include sport physiology, cell aging, disease produced cell damage, drug absorption capacity, to mention the most obvious ones.

  18. Epitope-Specific Vaccination Limits Clonal Expansion of Heterologous Naive T Cells during Viral Challenge

    Directory of Open Access Journals (Sweden)

    Lexus R. Johnson


    Full Text Available Despite robust secondary T cell expansion primed by vaccination, the impact on primary immune responses to heterotypic antigens remains undefined. Here we show that secondary expansion of epitope-specific memory CD8+ T cells primed by prior infection with recombinant pathogens limits the primary expansion of naive CD8+ T cells with specificity to new heterologous antigens, dampening protective immunity against subsequent pathogen challenge. The degree of naive T cell repression directly paralleled the magnitude of the recall response. Suppressed primary T cell priming reflects competition for antigen accessibility, since clonal expansion was not inhibited if the primary and secondary epitopes were expressed on different dendritic cells. Interestingly, robust recall responses did not impact antigen-specific NK cells, suggesting that adaptive and innate lymphocyte responses possess different activation requirements or occur in distinct anatomical locations. These findings have important implications in pathogen vaccination strategies that depend on the targeting of multiple T cell epitopes.

  19. Metabolic determinants of cancer cell sensitivity to glucose limitation and biguanides (United States)

    Birsoy, Kıvanç; Possemato, Richard; Lorbeer, Franziska K.; Bayraktar, Erol C.; Thiru, Prathapan; Yucel, Burcu; Wang, Tim; Chen, Walter W.; Clish, Clary B.; Sabatini, David M.


    As the concentrations of highly consumed nutrients, particularly glucose, are generally lower in tumours than in normal tissues, cancer cells must adapt their metabolism to the tumour microenvironment. A better understanding of these adaptations might reveal cancer cell liabilities that can be exploited for therapeutic benefit. Here we developed a continuous-flow culture apparatus (Nutrostat) for maintaining proliferating cells in low-nutrient media for long periods of time, and used it to undertake competitive proliferation assays on a pooled collection of barcoded cancer cell lines cultured in low-glucose conditions. Sensitivity to low glucose varies amongst cell lines, and an RNA interference (RNAi) screen pinpointed mitochondrial oxidative phosphorylation (OXPHOS) as the major pathway required for optimal proliferation in low glucose. We found that cell lines most sensitive to low glucose are defective in the OXPHOS upregulation that is normally caused by glucose limitation as a result of either mitochondrial DNA (mtDNA) mutations in complex I genes or impaired glucose utilization. These defects predict sensitivity to biguanides, antidiabetic drugs that inhibit OXPHOS, when cancer cells are grown in low glucose or as tumour xenografts. Notably, the biguanide sensitivity of cancer cells with mtDNA mutations was reversed by ectopic expression of yeast NDI1, a ubiquinone oxidoreductase that allows bypass of complex I function. Thus, we conclude that mtDNA mutations and impaired glucose utilization are potential biomarkers for identifying tumours with increased sensitivity to OXPHOS inhibitors.

  20. Recent advances on enzymatic glucose/oxygen and hydrogen/oxygen biofuel cells: Achievements and limitations (United States)

    Cosnier, Serge; J. Gross, Andrew; Le Goff, Alan; Holzinger, Michael


    The possibility of producing electrical power from chemical energy with biological catalysts has induced the development of biofuel cells as viable energy sources for powering portable and implanted electronic devices. These power sources employ biocatalysts, called enzymes, which are highly specific and catalytic towards the oxidation of a biofuel and the reduction of oxygen or hydrogen peroxide. Enzymes, on one hand, are promising candidates to replace expensive noble metal-based catalysts in fuel cell research. On the other hand, they offer the exciting prospect of a new generation of fuel cells which harvest energy from body fluids. Biofuel cells which use glucose as a fuel are particularly interesting for generating electricity to power electronic devices inside a living body. Hydrogen consuming biofuel cells represent an emerging alternative to platinum catalysts due to comparable efficiencies and the capability to operate at lower temperatures. Currently, these technologies are not competitive with existing commercialised fuel cell devices due to limitations including insufficient power outputs and lifetimes. The advantages and challenges facing glucose biofuel cells for implantation and hydrogen biofuel cells will be summarised along with recent promising advances and the future prospects of these exotic energy-harvesting devices.

  1. An improved model for nucleation-limited ice formation in living cells during freezing.

    Directory of Open Access Journals (Sweden)

    Jingru Yi

    Full Text Available Ice formation in living cells is a lethal event during freezing and its characterization is important to the development of optimal protocols for not only cryopreservation but also cryotherapy applications. Although the model for probability of ice formation (PIF in cells developed by Toner et al. has been widely used to predict nucleation-limited intracellular ice formation (IIF, our data of freezing Hela cells suggest that this model could give misleading prediction of PIF when the maximum PIF in cells during freezing is less than 1 (PIF ranges from 0 to 1. We introduce a new model to overcome this problem by incorporating a critical cell volume to modify the Toner's original model. We further reveal that this critical cell volume is dependent on the mechanisms of ice nucleation in cells during freezing, i.e., surface-catalyzed nucleation (SCN and volume-catalyzed nucleation (VCN. Taken together, the improved PIF model may be valuable for better understanding of the mechanisms of ice nucleation in cells during freezing and more accurate prediction of PIF for cryopreservation and cryotherapy applications.

  2. Stability of limit cycles in a pluripotent stem cell dynamics model

    Energy Technology Data Exchange (ETDEWEB)

    Adimy, Mostafa [Laboratoire de Mathematiques Appliquees UMR 5142, Universite de Pau et des Pays de l' Adour, Avenue de l' universite, 64000 Pau (France)] e-mail:; Crauste, Fabien [Laboratoire de Mathematiques Appliquees UMR 5142, Universite de Pau et des Pays de l' Adour, Avenue de l' universite, 64000 Pau (France)] e-mail:; Halanay, Andrei [Department of Mathematics 1, University Politehnica of Bucharest, Splaiul Independentei 313, RO-060042, Bucharest (Romania)] e-mail:; Neamtu, Mihaela [Faculty of Economics, I.N. Pestalozzi 16, West University of Timisoara, RO-300115, Timisoara (Romania)] e-mail:; Opris, Dumitru [Department of Applied Mathematics, Faculty of Mathematics, Bd. V. Parvan 4, West University of Timisoara, RO-300223, Timisoara (Romania)] e-mail:


    This paper is devoted to the study of the stability of limit cycles of a nonlinear delay differential equation with a distributed delay. The equation arises from a model of population dynamics describing the evolution of a pluripotent stem cells population. We study the local asymptotic stability of the unique nontrivial equilibrium of the delay equation and we show that its stability can be lost through a Hopf bifurcation. We then investigate the stability of the limit cycles yielded by the bifurcation using the normal form theory and the center manifold theorem. We illustrate our results with some numerics.

  3. Theoretical efficiency limit for a two-terminal multi-junction "step-cell" using detailed balance method (United States)

    Abdul Hadi, Sabina; Fitzgerald, Eugene A.; Nayfeh, Ammar


    Here we present detailed balance efficiency limit for a novel two-terminal dual and triple junction "step-cell" under AM 1.5G and AM 0 incident spectrums. The step-cell is a multi-junction (MJ) solar cell in which part of the top cell is removed, exposing some of the bottom cell area to unfiltered incident light, thus increasing bottom cell's photogenerated current. Optical generation of the bottom cell is modeled in two parts: step part, limited by the bottom cell bandgap, and conventional part, additionally limited by the top cell absorption. Our results show that conventionally designed MJ cell with optimized bandgap combination of 1.64 eV/0.96 eV for dual junction and 1.91 eV/1.37 eV/0.93 eV for triple junction has the highest theoretical efficiency limit. However, the step-cell design provides significant efficiency improvement for cells with non-optimum bandgap values. For example, for 1.41 eV ( ˜GaAs)/Si dual junction under AM 1.5G, efficiency limit increases from ˜21% in a conventional design to 38.7% for optimized step-cell. Similar benefits are observed for three-junction step-cell and for AM 0 spectrum studied here. Step-cell relaxes bandgap requirements for efficient MJ solar cells, providing an opportunity for a wider selection of materials and cost reduction.

  4. Cell nucleus - physical limitation of a quasar-galaxy association. Cell, DNA and cosmological background

    Energy Technology Data Exchange (ETDEWEB)

    Muheim, J.T. (Eidgenoessische Technische Hochschule, Zurich (Switzerland). Lab. fuer Festkoerperphysik)


    The author extends his analogy of atomic structure to cosmological structures to include the cell nucleus and DNA replication. From this the author believes that there is extraterrestrial life within 34 light years of us and that telepathy is possible within the solar system.

  5. Replication stress caused by low MCM expression limits fetal erythropoiesis and hematopoietic stem cell functionality

    DEFF Research Database (Denmark)

    Alvarez, Silvia; Díaz, Marcos; Flach, Johanna


    -chromosome maintenance (MCM)3 that limiting origin licensing in vivo affects the functionality of hematopoietic stem cells and the differentiation of rapidly-dividing erythrocyte precursors. Mcm3-deficient erythroblasts display aberrant DNA replication patterns and fail to complete maturation, causing lethal anemia. Our......' origins provide a backup in the presence of stalled forks and may confer flexibility to the replication program in specific cell types during differentiation, a role that has remained unexplored. Here we show, using a mouse strain with hypomorphic expression of the origin licensing factor mini...

  6. Intense Internal and External Fluorescence as Solar Cells Approach the Shockley-Queisser Efficiency Limit

    CERN Document Server

    Miller, Owen D; Kurtz, Sarah R


    Absorbed sunlight in a solar cell produces electrons and holes. But, at the open circuit condition, the carriers have no place to go. They build up in density and, ideally, they emit external fluorescence that exactly balances the incoming sunlight. Any additional non-radiative recombination impairs the carrier density buildup, limiting the open-circuit voltage. At open-circuit, efficient external fluorescence is an indicator of low internal optical losses. Thus efficient external fluorescence is, counter-intuitively, a necessity for approaching the Shockley-Queisser efficiency limit. A great Solar Cell also needs to be a great Light Emitting Diode. Owing to the narrow escape cone for light, efficient external emission requires repeated attempts, and demands an internal luminescence efficiency >>90%.

  7. Challenges and limitations of targeting cancer stem cells and/or the tumour microenvironment

    Directory of Open Access Journals (Sweden)

    Juan Sebastian Yakisich


    Full Text Available The existence of cancer cells with stem cell properties (Cancer Stem Cells, CSCs and their association with tumor resistance and relapse has led to the search for active compounds to eliminate these cells or modulate their stemness in the hope of curing cancer. So far, three classes of drugs that target cancer stemness (Stemness Modulator Drugs have been identified: i drugs that selectively eliminate CSCs (stem cell targeting drugs; ii drugs that decrease stemness (stemness inhibitor drugs; and iii drugs that promote stemness (stemness promoting drugs. In addition, microenvironment modulating drugs aimed at selectively targeting the stem cell niche are being investigated and may represent an important class of drug for cancer therapy. This article will briefly review the current use of these substances and discuss the potential outcomes, challenges and limitations of treatment modalities using these classes of drugs for cancer treatment. Finally, a modular tumor model will be proposed as a guide to integrate our knowledge on the biology of cancer stem cell with that of the tumor microenvironment to promote a more rational development of anticancer therapy.

  8. Limited transplantation of antigen-expressing hematopoietic stem cells induces long-lasting cytotoxic T cell responses.

    Directory of Open Access Journals (Sweden)

    Warren L Denning

    Full Text Available Harnessing the ability of cytotoxic T lymphocytes (CTLs to recognize and eradicate tumor or pathogen-infected cells is a critical goal of modern immune-based therapies. Although multiple immunization strategies efficiently induce high levels of antigen-specific CTLs, the initial increase is typically followed by a rapid contraction phase resulting in a sharp decline in the frequency of functional CTLs. We describe a novel approach to immunotherapy based on a transplantation of low numbers of antigen-expressing hematopoietic stem cells (HSCs following nonmyeloablative or partially myeloablative conditioning. Continuous antigen presentation by a limited number of differentiated transgenic hematopoietic cells results in an induction and prolonged maintenance of fully functional effector T cell responses in a mouse model. Recipient animals display high levels of antigen-specific CTLs four months following transplantation in contrast to dendritic cell-immunized animals in which the response typically declines at 4-6 weeks post-immunization. Majority of HSC-induced antigen-specific CD8+ T cells display central memory phenotype, efficiently kill target cells in vivo, and protect recipients against tumor growth in a preventive setting. Furthermore, we confirm previously published observation that high level engraftment of antigen-expressing HSCs following myeloablative conditioning results in tolerance and an absence of specific cytotoxic activity in vivo. In conclusion, the data presented here supports potential application of immunization by limited transplantation of antigen-expressing HSCs for the prevention and treatment of cancer and therapeutic immunization of chronic infectious diseases such as HIV-1/AIDS.

  9. Towards the efficiency limits of silicon solar cells: how thin is too thin?

    CERN Document Server

    Kowalczewski, Piotr


    It is currently possible to fabricate crystalline silicon solar cells with the absorber thickness ranging from a few hundreds of micrometers (conventional wafer-based cells) to devices as thin as $1\\,\\mu\\mathrm{m}$. In this work, we use a model single-junction solar cell to calculate the limits of energy conversion efficiency and estimate the optimal absorber thickness. The limiting efficiency for cells in the thickness range between 40 and $500\\,\\mu\\mathrm{m}$ is very similar and close to 29%. In this regard, we argue that decreasing the thickness below around $40\\,\\mu\\mathrm{m}$ is counter-productive, as it significantly reduces the maximum achievable efficiency, even when optimal light trapping is implemented. We analyse the roles of incomplete light trapping and extrinsic (bulk and surface) recombination mechanisms. For a reasonably high material quality, consistent with present-day fabrication techniques, the optimal thickness is always higher than a few tens of micrometers. We identify incomplete light ...

  10. Limited Gene Expression Variation in Human Embryonic Stem Cell and Induced Pluripotent Stem Cell Derived Endothelial Cells



    Recent evidence suggests human embryonic stem cell (hESC) and induced pluripotent stem (iPS) cell lines have differences in their epigenetic marks and transcriptomes, yet the impact of these differences on subsequent terminally differentiated cells is less well understood. Comparison of purified, homogeneous populations of somatic cells derived from multiple independent human iPS and ES lines will be required to address this critical question. Here, we report a differentiation protocol based ...

  11. Bioactive food components, cancer cell growth limitation and reversal of glycolytic metabolism. (United States)

    Keijer, Jaap; Bekkenkamp-Grovenstein, Melissa; Venema, Dini; Dommels, Yvonne E M


    Cancer cells are resistant to apoptosis and show a shift in energy production from mitochondrial oxidative phosphorylation to cytosolic glycolysis. Apoptosis resistance and metabolic reprogramming are linked in many cancer cells and both processes center on mitochondria. Clearly, mutated cancer cells escape surveillance and turn into selfish cells. However, many of the mechanisms that operate cellular metabolic control still function in cancer cells. This review describes the metabolic importance of glucose and glutamine, glycolytic enzymes, oxygen, growth cofactors and mitochondria and focuses on the potential role of bioactive food components, including micronutrients. The role of B- and A-vitamin cofactors in (mitochondrial) metabolism is highlighted and the cancer protective potential of omega-3 fatty acids and several polyphenols is discussed in relation to metabolic reprogramming, including the mechanisms that may be involved. Furthermore, it is shown that cancer cell growth reduction by limiting the growth cofactor folic acid seems to be associated with reversal of metabolic reprogramming. Altogether, reversal of metabolic reprogramming may be an attractive strategy to increase susceptibility to apoptotic surveillance. Food bioactive components that affect various aspects of metabolism may be important tools to reverse glycolytic to oxidative metabolism and enhance sensitivity to apoptosis. The success of such a strategy may depend on several actors, acting in concert. Growth cofactors may be one of these, which call for careful (re)evaluation of their function in normal and in cancer metabolism.

  12. Nutrient regulation by continuous feeding removes limitations on cell yield in the large-scale expansion of Mammalian cell spheroids.

    Directory of Open Access Journals (Sweden)

    Bradley P Weegman

    Full Text Available Cellular therapies are emerging as a standard approach for the treatment of several diseases. However, realizing the promise of cellular therapies across the full range of treatable disorders will require large-scale, controlled, reproducible culture methods. Bioreactor systems offer the scale-up and monitoring needed, but standard stirred bioreactor cultures do not allow for the real-time regulation of key nutrients in the medium. In this study, β-TC6 insulinoma cells were aggregated and cultured for 3 weeks as a model of manufacturing a mammalian cell product. Cell expansion rates and medium nutrient levels were compared in static, stirred suspension bioreactors (SSB, and continuously fed (CF SSB. While SSB cultures facilitated increased culture volumes, no increase in cell yields were observed, partly due to limitations in key nutrients, which were consumed by the cultures between feedings, such as glucose. Even when glucose levels were increased to prevent depletion between feedings, dramatic fluctuations in glucose levels were observed. Continuous feeding eliminated fluctuations and improved cell expansion when compared with both static and SSB culture methods. Further improvements in growth rates were observed after adjusting the feed rate based on calculated nutrient depletion, which maintained physiological glucose levels for the duration of the expansion. Adjusting the feed rate in a continuous medium replacement system can maintain the consistent nutrient levels required for the large-scale application of many cell products. Continuously fed bioreactor systems combined with nutrient regulation can be used to improve the yield and reproducibility of mammalian cells for biological products and cellular therapies and will facilitate the translation of cell culture from the research lab to clinical applications.

  13. Nutrient regulation by continuous feeding removes limitations on cell yield in the large-scale expansion of Mammalian cell spheroids. (United States)

    Weegman, Bradley P; Nash, Peter; Carlson, Alexandra L; Voltzke, Kristin J; Geng, Zhaohui; Jahani, Marjan; Becker, Benjamin B; Papas, Klearchos K; Firpo, Meri T


    Cellular therapies are emerging as a standard approach for the treatment of several diseases. However, realizing the promise of cellular therapies across the full range of treatable disorders will require large-scale, controlled, reproducible culture methods. Bioreactor systems offer the scale-up and monitoring needed, but standard stirred bioreactor cultures do not allow for the real-time regulation of key nutrients in the medium. In this study, β-TC6 insulinoma cells were aggregated and cultured for 3 weeks as a model of manufacturing a mammalian cell product. Cell expansion rates and medium nutrient levels were compared in static, stirred suspension bioreactors (SSB), and continuously fed (CF) SSB. While SSB cultures facilitated increased culture volumes, no increase in cell yields were observed, partly due to limitations in key nutrients, which were consumed by the cultures between feedings, such as glucose. Even when glucose levels were increased to prevent depletion between feedings, dramatic fluctuations in glucose levels were observed. Continuous feeding eliminated fluctuations and improved cell expansion when compared with both static and SSB culture methods. Further improvements in growth rates were observed after adjusting the feed rate based on calculated nutrient depletion, which maintained physiological glucose levels for the duration of the expansion. Adjusting the feed rate in a continuous medium replacement system can maintain the consistent nutrient levels required for the large-scale application of many cell products. Continuously fed bioreactor systems combined with nutrient regulation can be used to improve the yield and reproducibility of mammalian cells for biological products and cellular therapies and will facilitate the translation of cell culture from the research lab to clinical applications.

  14. DAZL Limits Pluripotency, Differentiation, and Apoptosis in Developing Primordial Germ Cells

    Directory of Open Access Journals (Sweden)

    Hsu-Hsin Chen


    Full Text Available The scarcity of primordial germ cells (PGCs in the developing mammalian embryo hampers robust biochemical analysis of the processes that underlie early germ cell formation. Here, we demonstrate that DAZL, a germ cell-specific RNA binding protein, is a robust PGC marker during in vitro germ cell development. Using Dazl-GFP reporter ESCs, we demonstrate that DAZL plays a central role in a large mRNA/protein interactive network that blocks the translation of core pluripotency factors, including Sox2 and Sall4, as well as of Suz12, a polycomb family member required for differentiation of pluripotent cells. Thus, DAZL limits both pluripotency and somatic differentiation in nascent PGCs. In addition, we observed that DAZL associates with mRNAs of key Caspases and similarly inhibits their translation. This elegant fail-safe mechanism ensures that, whereas loss of DAZL results in prolonged expression of pluripotency factors, teratoma formation is avoided due to the concomitant activation of the apoptotic cascade.

  15. A generic concept to overcome bandgap limitations for designing highly efficient multi-junction photovoltaic cells. (United States)

    Guo, Fei; Li, Ning; Fecher, Frank W; Gasparini, Nicola; Ramirez Quiroz, Cesar Omar; Bronnbauer, Carina; Hou, Yi; Radmilović, Vuk V; Radmilović, Velimir R; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J


    The multi-junction concept is the most relevant approach to overcome the Shockley-Queisser limit for single-junction photovoltaic cells. The record efficiencies of several types of solar technologies are held by series-connected tandem configurations. However, the stringent current-matching criterion presents primarily a material challenge and permanently requires developing and processing novel semiconductors with desired bandgaps and thicknesses. Here we report a generic concept to alleviate this limitation. By integrating series- and parallel-interconnections into a triple-junction configuration, we find significantly relaxed material selection and current-matching constraints. To illustrate the versatile applicability of the proposed triple-junction concept, organic and organic-inorganic hybrid triple-junction solar cells are constructed by printing methods. High fill factors up to 68% without resistive losses are achieved for both organic and hybrid triple-junction devices. Series/parallel triple-junction cells with organic, as well as perovskite-based subcells may become a key technology to further advance the efficiency roadmap of the existing photovoltaic technologies.

  16. A generic concept to overcome bandgap limitations for designing highly efficient multi-junction photovoltaic cells (United States)

    Guo, Fei; Li, Ning; Fecher, Frank W.; Gasparini, Nicola; Quiroz, Cesar Omar Ramirez; Bronnbauer, Carina; Hou, Yi; Radmilović, Vuk V.; Radmilović, Velimir R.; Spiecker, Erdmann; Forberich, Karen; Brabec, Christoph J.


    The multi-junction concept is the most relevant approach to overcome the Shockley–Queisser limit for single-junction photovoltaic cells. The record efficiencies of several types of solar technologies are held by series-connected tandem configurations. However, the stringent current-matching criterion presents primarily a material challenge and permanently requires developing and processing novel semiconductors with desired bandgaps and thicknesses. Here we report a generic concept to alleviate this limitation. By integrating series- and parallel-interconnections into a triple-junction configuration, we find significantly relaxed material selection and current-matching constraints. To illustrate the versatile applicability of the proposed triple-junction concept, organic and organic-inorganic hybrid triple-junction solar cells are constructed by printing methods. High fill factors up to 68% without resistive losses are achieved for both organic and hybrid triple-junction devices. Series/parallel triple-junction cells with organic, as well as perovskite-based subcells may become a key technology to further advance the efficiency roadmap of the existing photovoltaic technologies. PMID:26177808

  17. Klebsiella pneumoniae alleviates influenza-induced acute lung injury via limiting NK cell expansion. (United States)

    Wang, Jian; Li, Fengqi; Sun, Rui; Gao, Xiang; Wei, Haiming; Tian, Zhigang


    A protective effect induced by bacterial preinfection upon a subsequent lethal influenza virus infection has been observed, but the underlying immune mechanisms have not yet been fully elucidated. In this study, we used a mouse model of Klebsiella pneumoniae preinfection to gain insight into how bacterial preinfection influences the subsequent lethal influenza virus infection. We found that K. pneumoniae preinfection significantly attenuated lung immune injury and decreased mortality during influenza virus infection, but K. pneumoniae-specific immunity was not involved in this cross-protection against influenza virus. K. pneumoniae preinfection limited NK cell expansion, which was involved in influenza-induced immune injury and death. Furthermore, K. pneumoniae preinfection could not control NK cell expansion and death during influenza virus infection in Rag1(-/-) mice, but adoptive transfer of T cells from wild-type mice was able to restore this protective effect. Our data suggest that the adaptive immune response activated by bacterial infection limits the excessive innate immune response induced by a subsequent influenza infection, ultimately protecting mice from death.

  18. Adult neurogenesis, neural stem cells and Alzheimer's disease: developments, limitations, problems and promises. (United States)

    Taupin, Philippe


    Alzheimer's disease (AD) is an irreversible progressive neurodegenerative disease, leading to severe incapacity and death. It is the most common form of dementia among older people. AD is characterized in the brain by amyloid plaques, neurofibrillary tangles, neuronal degeneration, aneuploidy and enhanced neurogenesis and by cognitive, behavioral and physical impairments. Inherited mutations in several genes and genetic, acquired and environmental risk factors have been reported as causes for developing the disease, for which there is currently no cure. Current treatments for AD involve drugs and occupational therapies, and future developments involve early diagnosis and stem cell therapy. In this manuscript, we will review and discuss the recent developments, limitations, problems and promises on AD, particularly related to aneuploidy, adult neurogenesis, neural stem cells (NSCs) and cellular therapy. Though adult neurogenesis may be beneficial for regeneration of the nervous system, it may underly the pathogenesis of AD. Cellular therapy is a promising strategy for AD. Limitations in protocols to establish homogeneous populations of neural progenitor and stem cells and niches for neurogenesis need to be resolved and unlocked, for the full potential of adult NSCs to be realized for therapy.

  19. Telomerase inhibitor Imetelstat (GRN163L limits the lifespan of human pancreatic cancer cells.

    Directory of Open Access Journals (Sweden)

    Katrina M Burchett

    Full Text Available Telomerase is required for the unlimited lifespan of cancer cells. The vast majority of pancreatic adenocarcinomas overexpress telomerase activity and blocking telomerase could limit their lifespan. GRN163L (Imetelstat is a lipid-conjugated N3'→P5' thio-phosphoramidate oligonucleotide that blocks the template region of telomerase. The aim of this study was to define the effects of long-term GRN163L exposure on the maintenance of telomeres and lifespan of pancreatic cancer cells. Telomere size, telomerase activity, and telomerase inhibition response to GRN163L were measured in a panel of 10 pancreatic cancer cell lines. The cell lines exhibited large differences in levels of telomerase activity (46-fold variation, but most lines had very short telomeres (2-3 kb in size. GRN163L inhibited telomerase in all 10 pancreatic cancer cell lines, with IC50 ranging from 50 nM to 200 nM. Continuous GRN163L exposure of CAPAN1 (IC50 = 75 nM and CD18 cells (IC50 = 204 nM resulted in an initial rapid shortening of the telomeres followed by the maintenance of extremely short but stable telomeres. Continuous exposure to the drug eventually led to crisis and to a complete loss of viability after 47 (CAPAN1 and 69 (CD18 doublings. Crisis In these cells was accompanied by activation of a DNA damage response (γ-H2AX and evidence of both senescence (SA-β-galactosidase activity and apoptosis (sub-G1 DNA content, PARP cleavage. Removal of the drug after long-term GRN163L exposure led to a reactivation of telomerase and re-elongation of telomeres in the third week of cultivation without GRN163L. These findings show that the lifespan of pancreatic cancer cells can be limited by continuous telomerase inhibition. These results should facilitate the design of future clinical trials of GRN163L in patients with pancreatic cancer.

  20. Telomerase inhibitor Imetelstat (GRN163L) limits the lifespan of human pancreatic cancer cells. (United States)

    Burchett, Katrina M; Yan, Ying; Ouellette, Michel M


    Telomerase is required for the unlimited lifespan of cancer cells. The vast majority of pancreatic adenocarcinomas overexpress telomerase activity and blocking telomerase could limit their lifespan. GRN163L (Imetelstat) is a lipid-conjugated N3'→P5' thio-phosphoramidate oligonucleotide that blocks the template region of telomerase. The aim of this study was to define the effects of long-term GRN163L exposure on the maintenance of telomeres and lifespan of pancreatic cancer cells. Telomere size, telomerase activity, and telomerase inhibition response to GRN163L were measured in a panel of 10 pancreatic cancer cell lines. The cell lines exhibited large differences in levels of telomerase activity (46-fold variation), but most lines had very short telomeres (2-3 kb in size). GRN163L inhibited telomerase in all 10 pancreatic cancer cell lines, with IC50 ranging from 50 nM to 200 nM. Continuous GRN163L exposure of CAPAN1 (IC50 = 75 nM) and CD18 cells (IC50 = 204 nM) resulted in an initial rapid shortening of the telomeres followed by the maintenance of extremely short but stable telomeres. Continuous exposure to the drug eventually led to crisis and to a complete loss of viability after 47 (CAPAN1) and 69 (CD18) doublings. Crisis In these cells was accompanied by activation of a DNA damage response (γ-H2AX) and evidence of both senescence (SA-β-galactosidase activity) and apoptosis (sub-G1 DNA content, PARP cleavage). Removal of the drug after long-term GRN163L exposure led to a reactivation of telomerase and re-elongation of telomeres in the third week of cultivation without GRN163L. These findings show that the lifespan of pancreatic cancer cells can be limited by continuous telomerase inhibition. These results should facilitate the design of future clinical trials of GRN163L in patients with pancreatic cancer.

  1. Activation energy spectra: insights into transport limitations of organic semiconductors and photovoltaic cells

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Ziqi; Nardes, Alexandre M.; Van de Lagemaat, Jao; Gregg, Brian A. [National Renewable Energy Laboratory, Golden, CO (United States)


    Some mechanisms of charge transport in organic semiconductors and organic photovoltaic (OPV) cells can be distinguished by their predicted change in activation energy for the current, E{sub a}, versus applied field, F. E{sub a} versus F is measured first in pure films of commercially available regioregular poly(3-hexylthiophene) (P3HT) and in the same P3HT treated to reduce its charged defect density. The former shows a Poole-Frenkel (PF)-like decrease in E{sub a} at low F, which then plateaus at higher F. The low defect material does not exhibit PF behavior and E{sub a} remains approximately constant. Upon addition of [6,6]-phenyl-C{sub 61}-butyric acid methyl ester (PCBM), however, both materials show a large increase in E{sub a} and exhibit PF-like behavior over the entire field range. These results are explained with a previously proposed model of transport that considers both the localized random disorder in the energy levels and the long-range electrostatic fluctuations resulting from charged defects. Activation energy spectra in working OPV cells show that the current is injection-limited over most of the voltage range but becomes transport-limited, with a large peak in E{sub a}, near the open circuit photovoltage. This causes a decrease in fill factor, which may be a general limitation in such solar cells. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. Cdc45 limits replicon usage from a low density of preRCs in mammalian cells. (United States)

    Wong, Philip G; Winter, Sherry L; Zaika, Elena; Cao, Thinh V; Oguz, Umut; Koomen, John M; Hamlin, Joyce L; Alexandrow, Mark G


    Little is known about mammalian preRC stoichiometry, the number of preRCs on chromosomes, and how this relates to replicon size and usage. We show here that, on average, each 100-kb of the mammalian genome contains a preRC composed of approximately one ORC hexamer, 4-5 MCM hexamers, and 2 Cdc6. Relative to these subunits, ∼0.35 total molecules of the pre-Initiation Complex factor Cdc45 are present. Thus, based on ORC availability, somatic cells contain ∼70,000 preRCs of this average total stoichiometry, although subunits may not be juxtaposed with each other. Except for ORC, the chromatin-bound complement of preRC subunits is even lower. Cdc45 is present at very low levels relative to the preRC subunits, but is highly stable, and the same limited number of stable Cdc45 molecules are present from the beginning of S-phase to its completion. Efforts to artificially increase Cdc45 levels through ectopic expression block cell growth. However, microinjection of excess purified Cdc45 into S-phase nuclei activates additional replication foci by three-fold, indicating that Cdc45 functions to activate dormant preRCs and is rate-limiting for somatic replicon usage. Paradoxically, although Cdc45 colocalizes in vivo with some MCM sites and is rate-limiting for DNA replication to occur, neither Cdc45 nor MCMs colocalize with active replication sites. Embryonic metazoan chromatin consists of small replicons that are used efficiently via an excess of preRC subunits. In contrast, somatic mammalian cells contain a low density of preRCs, each containing only a few MCMs that compete for limiting amounts of Cdc45. This provides a molecular explanation why, relative to embryonic replicon dynamics, somatic replicons are, on average, larger and origin efficiency tends to be lower. The stable, continuous, and rate-limiting nature of Cdc45 suggests that Cdc45 contributes to the staggering of replicon usage throughout S-phase, and that replicon activation requires reutilization of

  3. Speeding Up Simulations By Slowing Down Particles: Speed-Limited Particle-In-Cell Simulation

    CERN Document Server

    Werner, Gregory R


    Particle-in-cell (PIC) simulation is often impractical for the same reason that it is powerful: it includes too much physics. Sometimes the mere ability to simulate physics on small length or time scales requires those scales to be resolved (by the cell size and timestep) to avoid instability, even when the effects at those scales contribute negligibly to the phenomenon motivating the simulation. For example, a timestep larger than the inverse plasma frequency will often result in unphysical growth of plasma oscillations, even in simulations where plasma oscillations should not arise at all. Larger timesteps are possible in simulations based on reduced physics models, such as MHD or gyrokinetics, or in simulations with implicit time-advances. A new method, speed-limited PIC (SLPIC) simulation, allows larger timesteps without reduced physics and with an explicit time-advance. The SLPIC method slows down fast particles while still accurately representing the particle distribution. SLPIC is valid when fields and...

  4. Limiting efficiency calculation of silicon single-nanowire solar cells with considering Auger recombination

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Xiongfei; Wu, Shaolong; Shang, Aixue; Li, Xiaofeng, E-mail: [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006 (China)


    Single-nanowire solar cells (SNSCs) have attracted considerable attention due to their unique light-harvesting capability mediated by the optical antenna effect and the high photoconversion efficiency due to the orthogonalization of the carrier collection to the photon incidence. We present a detailed prediction of the light-conversion efficiency of Si SNSCs based on finite-element simulation and thermodynamic balance analysis, with especially focusing on the comparison between SNSCs and film systems. Carrier losses due to radiative and Auger recombinations are introduced in the analysis of the limiting efficiency, which show that the Auger recombination plays a key role in accurately predicting the efficiency of Si SNSCs, otherwise, the device performance would be strongly overestimated. The study paves a more realistic way to evaluate the nanostructured solar cells based on indirect-band photoactive materials.

  5. Establishing the limits of efficiency of perovskite solar cells from first principles modeling (United States)

    Grånäs, Oscar; Vinichenko, Dmitry; Kaxiras, Efthimios


    The recent surge in research on metal-halide-perovskite solar cells has led to a seven-fold increase of efficiency, from ~3% in early devices to over 22% in research prototypes. Oft-cited reasons for this increase are: (i) a carrier diffusion length reaching hundreds of microns; (ii) a low exciton binding energy; and (iii) a high optical absorption coefficient. These hybrid organic-inorganic materials span a large chemical space with the perovskite structure. Here, using first-principles calculations and thermodynamic modelling, we establish that, given the range of band-gaps of the metal-halide-perovskites, the theoretical maximum efficiency limit is in the range of ~25–27%. Our conclusions are based on the effect of level alignment between the perovskite absorber layer and carrier-transporting materials on the performance of the solar cell as a whole. Our results provide a useful framework for experimental searches toward more efficient devices.

  6. Inhibition of RORγT Skews TCRα Gene Rearrangement and Limits T Cell Repertoire Diversity

    Directory of Open Access Journals (Sweden)

    Yanxia Guo


    Full Text Available Recent studies have elucidated the molecular mechanism of RORγT transcriptional regulation of Th17 differentiation and function. RORγT was initially identified as a transcription factor required for thymopoiesis by maintaining survival of CD4+CD8+ (DP thymocytes. While RORγ antagonists are currently being developed to treat autoimmunity, it remains unclear how RORγT inhibition may impact thymocyte development. In this study, we show that in addition to regulating DP thymocytes survival, RORγT also controls genes that regulate thymocyte migration, proliferation, and T cell receptor (TCRα selection. Strikingly, pharmacological inhibition of RORγ skews TCRα gene rearrangement, limitscell repertoire diversity, and inhibits development of autoimmune encephalomyelitis. Thus, targeting RORγT not only inhibits Th17 cell development and function but also fundamentally alters thymic-emigrant recognition of self and foreign antigens. The analysis of RORγ inhibitors has allowed us to gain a broader perspective of the diverse function of RORγT and its impact on T cell biology.

  7. Hydrogel limits stem cell dispersal in the deaf cochlea: implications for cochlear implants (United States)

    Nayagam, Bryony A.; Backhouse, Steven S.; Cimenkaya, Cengiz; Shepherd, Robert K.


    Auditory neurons provide the critical link between a cochlear implant and the brain in deaf individuals, therefore their preservation and/or regeneration is important for optimal performance of this neural prosthesis. In cases where auditory neurons are significantly depleted, stem cells (SCs) may be used to replace the lost population of neurons, thereby re-establishing the critical link between the periphery (implant) and the brain. For such a therapy to be therapeutically viable, SCs must be differentiated into neurons, retained at their delivery site and damage caused to the residual auditory neurons minimized. Here we describe the transplantation of SC-derived neurons into the deaf cochlea, using a peptide hydrogel to limit their dispersal. The described approach illustrates that SCs can be delivered to and are retained within the basal turn of the cochlea, without a significant loss of endogenous auditory neurons. In addition, the tissue response elicited from this surgical approach was restricted to the surgical site and did not extend beyond the cochlear basal turn. Overall, this approach illustrates the feasibility of targeted cell delivery into the mammalian cochlea using hydrogel, which may be useful for future cell-based transplantation strategies, for combined treatment with a cochlear implant to restore function.

  8. PERK promotes cancer cell proliferation and tumor growth by limiting oxidative DNA damage (United States)

    Bobrovnikova-Marjon, Ekaterina; Grigoriadou, Christina; Pytel, Dariusz; Zhang, Fang; Ye, Jiangbin; Koumenis, Constantinos; Cavener, Douglas; Diehl, J. Alan


    In order to proliferate and expand in an environment with limited nutrients, cancer cells co-opt cellular regulatory pathways that facilitate adaptation and thereby maintain tumor growth and survival potential. The endoplasmic reticulum (ER) is uniquely positioned to sense nutrient deprivation stress and subsequently engage signaling pathways that promote adaptive strategies. As such, components of the ER stress-signaling pathway represent potential anti-neoplastic targets. However, recent investigations into the role of the ER resident protein kinase PERK have paradoxically suggested both pro- and anti-tumorigenic properties. We have utilized animal models of mammary carcinoma to interrogate PERK contribution in the neoplastic process. The ablation of PERK in tumor cells resulted in impaired regeneration of intracellular antioxidants and accumulation of reactive oxygen species triggering oxidative DNA damage. Ultimately, PERK deficiency impeded progression through the cell cycle due to the activation of the DNA damage checkpoint. Our data reveal that PERK-dependent signaling is utilized during both tumor initiation and expansion to maintain redox homeostasis and thereby facilitates tumor growth. PMID:20453876

  9. PERK promotes cancer cell proliferation and tumor growth by limiting oxidative DNA damage. (United States)

    Bobrovnikova-Marjon, E; Grigoriadou, C; Pytel, D; Zhang, F; Ye, J; Koumenis, C; Cavener, D; Diehl, J A


    To proliferate and expand in an environment with limited nutrients, cancer cells co-opt cellular regulatory pathways that facilitate adaptation and thereby maintain tumor growth and survival potential. The endoplasmic reticulum (ER) is uniquely positioned to sense nutrient deprivation stress and subsequently engage signaling pathways that promote adaptive strategies. As such, components of the ER stress-signaling pathway represent potential antineoplastic targets. However, recent investigations into the role of the ER resident protein kinase, RNA-dependent protein kinase (PKR)-like ER kinase (PERK) have paradoxically suggested both pro- and anti-tumorigenic properties. We have used animal models of mammary carcinoma to interrogate the contribution of PERK in the neoplastic process. The ablation of PERK in tumor cells resulted in impaired regeneration of intracellular antioxidants and accumulation of reactive oxygen species triggering oxidative DNA damage. Ultimately, PERK deficiency impeded progression through the cell cycle because of the activation of the DNA damage checkpoint. Our data reveal that PERK-dependent signaling is used during both tumor initiation and expansion to maintain redox homeostasis, thereby facilitating tumor growth.

  10. On channel quantization for multi-cell cooperative systems with limited feedback

    Institute of Scientific and Technical Information of China (English)

    HOU XueYing; YANG ChenYang; LAU Buon Kiong


    Coherent multi-cell cooperative transmission, also referred to as coordinated multi-point transmission (CoMP), is a promising strategy to provide high spectral efficiency for universal frequency reuse cellular systems. To report the required channel information to the transmitter in frequency division duplexing systems, limited feedback techniques are often applied. Considering that the average channel gains from multiple base stations (BSs) to one mobile station are different and the number of cooperative BSs may be dynamic, it is neither flexible nor compatible to employ a large codebook to directly quantize the CoMP channel. In this paper, we employ per-cell codebooks for quantizing local and cross channels. We first propose a codeword selection criterion, aiming at maximizing an estimated data rate for each user. The proposed criterion can be applied for an arbitrary number of receive antennas at each user and also for an arbitrary number of data streams transmitted to each user. Considering that the resulting optimal per-cell codeword selection for CoMP channel is of high complexity, we propose a serial codeword selection method that has low complexity but yields comparable performance to that of the optimal codeword selection. We evaluate the proposed codeword selection criterion and method using measured CoMP channels from an urban environment as well as simulations. The results demonstrate significant performance gain as compared to an existing low-complexity method.

  11. Limitations on the open-circuit voltage imposed by P/+/ and N/+/ regions in silicon solar cells (United States)

    Shibib, M. A.; Fossum, J. G.


    It is shown theoretically and experimentally that the emitter recombination current, which limits the open-circuit voltage of silicon solar cells, can be more easily suppressed in P(+)N cells than in N(+)P cells. This result is due to fundamental effects that occur in heavily doped silicon: degeneracy of the majority charge carriers, Auger recombination, and energy-band-gap narrowing. Cell designs to suppress the emitter current are discussed, and experimental data supporting our theoretical analysis are presented.

  12. Combined chemotherapy and radiation therapy in limited disease small-cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Moon Kyung; Ahn, Yong Chan; Park, Keun Chil; Lim Do Hoon; Huh, Seung Jae; Kim, Dae Yong; Shin, Kyung Hwan; Lee, Kyu Chan; Kwon, O Jung [College of Medicine, Sungkyunkwan Univ., Seoul (Korea, Republic of)


    This is a retrospective study to evaluate the response rate, acute toxicity, and survival rate of a combined chemotherapy and radiation therapy in limited disease small cell lung cancer. Forty six patients with limited disease small-cell lung cancer who underwent combined chemotherapy and radiation therapy between October 1994 and April 1998 were evaluated. Six cycles of chemotherapy were planned either using a VIP regimen (etoposide, ifosfamide, and cis-platin) or a EP regimen (etoposide and cis-platin). Thoracic radiation therapy was planned to deliver 44 Gy using 10MV X-ray, starting concurrently with chemotherapy. Response was evaluated 4 weeks after the completion of the planned chemotherapy and radiation therapy, and the prophylactic cranial irradiation was planned only for the patients with complete responses. Acute toxicity was evaluated using the SWOG toxicity criteria, and the overall survival and disease-free survival were calculated using the Kaplan-Meier Method. The median follow-up period was 16 months (range:2 to 41 months). Complete response was achieved in 30 (65%) patients, of which 22 patients received prophylactic cranial irradiations. Acute toxicities over grade III were granulocytopenia in 23 (50%), anemia in 17 (37%), thrombo-cytopenia in nine (20%), alopecia in nine (20%), nausea/vomiting in five (11%), and peripheral neuropathy in one (2%). Chemotherapy was delayed in one patient, and the chemotherapy doses were reduced in 58 (24%) out of the total 246 cycles. No radiation esophagitis over grade III was observed, while interruption during radiation therapy for a mean of 8.3 days occurred in 21 patients. The local recurrences were observed in 8 patients and local progressions were in 6 patients, and the distant metastases in 17 patients. Among these, four patients had both the local relapse and the distant metastasis. Brain was the most common metastatic site (10 patients), followed by the liver as the next common site (4 patients). The

  13. Coxiella burnetii Infects Primary Bovine Macrophages and Limits Their Host Cell Response. (United States)

    Sobotta, Katharina; Hillarius, Kirstin; Mager, Marvin; Kerner, Katharina; Heydel, Carsten; Menge, Christian


    Although domestic ruminants have long been recognized as the main source of human Q fever, little is known about the lifestyle that the obligate intracellular Gram-negative bacterium Coxiella burnetii adopts in its animal host. Because macrophages are considered natural target cells of the pathogen, we established primary bovine monocyte-derived macrophages (MDM) as an in vitro infection model to study reservoir host-pathogen interactions at the cellular level. In addition, bovine alveolar macrophages were included to take cell type peculiarities at a host entry site into account. Cell cultures were inoculated with the virulent strain Nine Mile I (NMI; phase I) or the avirulent strain Nine Mile II (NMII; phase II). Macrophages from both sources internalized NMI and NMII. MDM were particularly permissive for NMI internalization, but NMI and NMII replicated with similar kinetics in these cells. MDM responded to inoculation with a general upregulation of Th1-related cytokines such as interleukin-1β (IL-1β), IL-12, and tumor necrosis factor alpha (TNF-α) early on (3 h postinfection). However, inflammatory responses rapidly declined when C. burnetii replication started. C. burnetii infection inhibited translation and release of IL-1β and vastly failed to stimulate increased expression of activation markers, such as CD40, CD80, CD86, and major histocompatibility complex (MHC) molecules. Such capability of limiting proinflammatory responses may help Coxiella to protect itself from clearance by the host immune system. The findings provide the first detailed insight into C. burnetii-macrophage interactions in ruminants and may serve as a basis for assessing the virulence and the host adaptation of C. burnetii strains.

  14. JNK mitogen-activated protein kinase limits calcium-dependent chloride secretion across colonic epithelial cells.

    LENUS (Irish Health Repository)

    Donnellan, Fergal


    Neuroimmune agonists induce epithelial Cl(-) secretion through elevations in intracellular Ca2+ or cAMP. Previously, we demonstrated that epidermal growth factor receptor (EGFR) transactivation and subsequent ERK MAPK activation limits secretory responses to Ca2+-dependent, but not cAMP-dependent, agonists. Although JNK MAPKs are also expressed in epithelial cells, their role in regulating transport function is unknown. Here, we investigated the potential role for JNK in regulating Cl(-) secretion in T(84) colonic epithelial cells. Western blot analysis revealed that a prototypical Ca2+-dependent secretagogue, carbachol (CCh; 100 microM), induced phosphorylation of both the 46-kDa and 54-kDa isoforms of JNK. This effect was mimicked by thapsigargin (TG), which specifically elevates intracellular Ca2+, but not by forskolin (FSK; 10 microM), which elevates cAMP. CCh-induced JNK phosphorylation was attenuated by the EGFR inhibitor, tyrphostin-AG1478 (1 microM). Pretreatment of voltage-clamped T(84) cells with SP600125 (2 microM), a specific JNK inhibitor, potentiated secretory responses to both CCh and TG but not to FSK. The effects of SP600125 on CCh-induced secretion were not additive with those of the ERK inhibitor, PD98059. Finally, in apically permeabilized T(84) cell monolayers, SP600125 potentiated CCh-induced K+ conductances but not Na+\\/K+ATPase activity. These data demonstrate a novel role for JNK MAPK in regulating Ca2+ but not cAMP-dependent epithelial Cl(-) secretion. JNK activation is mediated by EGFR transactivation and exerts its antisecretory effects through inhibition of basolateral K+ channels. These data further our understanding of mechanisms regulating epithelial secretion and underscore the potential for exploitation of MAPK-dependent signaling in treatment of intestinal transport disorders.

  15. Exceeding the solar cell Shockley-Queisser limit via thermal up-conversion of low-energy photons

    CERN Document Server

    Boriskina, Svetlana V


    Maximum efficiency of ideal single-junction photovoltaic (PV) cells is limited to 33% (for one sun illumination) by intrinsic losses such as band edge thermalization, radiative recombination, and inability to absorb below-bandgap photons. This intrinsic thermodynamic limit, named after Shockley and Queisser (S-Q), can be exceeded by utilizing low-energy photons either via their electronic up-conversion or via thermophotovoltaic (TPV) conversion process. However, electronic up-conversion systems have extremely low efficiencies, and practical temperature considerations limit the operation of TPV converters to the narrow-gap PV cells. Here we develop a conceptual design of a hybrid TPV platform, which exploits thermal up-conversion of low-energy photons and is compatible with conventional silicon PV cells by using spectral and directional selectivity of the up-converter. The hybrid platform offers sunlight-to-electricity conversion efficiency exceeding that imposed by the S-Q limit on the corresponding PV cells ...

  16. Conductive polymer layers to limit transfer of fuel reactants to catalysts of fuel cells to reduce reactant crossover

    Energy Technology Data Exchange (ETDEWEB)

    Stanis, Ronald J.; Lambert, Timothy N.


    An apparatus of an aspect includes a fuel cell catalyst layer. The fuel cell catalyst layer is operable to catalyze a reaction involving a fuel reactant. A fuel cell gas diffusion layer is coupled with the fuel cell catalyst layer. The fuel cell gas diffusion layer includes a porous electrically conductive material. The porous electrically conductive material is operable to allow the fuel reactant to transfer through the fuel cell gas diffusion layer to reach the fuel cell catalyst layer. The porous electrically conductive material is also operable to conduct electrons associated with the reaction through the fuel cell gas diffusion layer. An electrically conductive polymer material is coupled with the fuel cell gas diffusion layer. The electrically conductive polymer material is operable to limit transfer of the fuel reactant to the fuel cell catalyst layer.

  17. Association of mast cells with calcification in the human pineal gland. (United States)

    Maślińska, Danuta; Laure-Kamionowska, Milena; Deręgowski, Krzysztof; Maśliński, Sławomir


    Increased pineal calcifications and decreased pineal melatonin biosynthesis, both age related, support the notion of a pineal bio-organic timing mechanism. The role of calcification in the pathogenesis of pineal gland dysfunction remains unknown but the available data document that calcification is an organized, regulated process, rather than a passive aging phenomenon. The cellular biology and micro-environmental conditions required for calcification remain poorly understood but most studies have demonstrated evidence that mast cells are strongly implicated in this process. The aim of the present study was to examine the phenotype of mast cells associated with early stages and with the progressive development of calcification in the human pineal gland. The study was performed on pineal samples of 170 fetuses and children whose brains were autopsied and diagnosed during 1998-2002. The representative cerebral and pineal specimens were stained with haematoxylin and eosin or the von Kossa staining technique and for the distribution of mast cell tryptase, mast cell chymase, histamine H4 receptor and vascular network using biotinylated Ulex europaeus agglutinin. Tryptase mast cells were found in all stages of pineal gland development independently of the presence of local tissue lesions. All of them were always localized in the close vicinity of the blood vessels and expressed immunoreactivity to histamine H4 receptor antibody. Immunolocalization of mast cells by chymase antibody (and following dual immunostaining with both chymase and tryptase antibodies) demonstrated that these cells were few in number and were located in the subcapsular region of the gland. In our study, all functional mast cells that underwent activation and were co-localized with deposits of calcium did not contain chymase. All of them were stained with tryptase and represent the MC-T phenotype. Tryptase mast cells and extracellular tryptase were often associated with areas of early and more

  18. Prospective study on stereotactic radiotherapy of limited-stage non-small-cell lung cancer

    DEFF Research Database (Denmark)

    Høyer, Morten; Roed, Henrik; Hansen, Anders Traberg


    Purpose: To test the effect of stereotactic body radiotherapy (SBRT) in       the treatment of medically inoperable patients with limited-stage       non-small-cell lung cancer (NSCLC) in a Phase II trial. Methods and       Materials: Forty patients with Stage I NSCLC were treated with SBRT...... resulted in a high       probability of local control and a promising survival rate. The toxicity       after SBRT of lung tumors was moderate. However, deterioration in       performance status, respiratory insufficiency, and other side effects were       observed...

  19. Effects of Photovoltaic and Fuel Cell Hybrid System on Distribution Network Considering the Voltage Limits

    Directory of Open Access Journals (Sweden)

    ABYANEH, H. A.


    Full Text Available Development of distribution network and power consumption growth, increase voltage drop on the line impedance and therefore voltage drop in system buses. In some cases consumption is so high that voltage in some buses exceed from standard. In this paper, effect of the fuel cell and photovoltaic hybrid system on distribution network for solving expressed problem is studied. For determining the capacity of each distributed generation source, voltage limitation on the bus voltages under different conditions is considered. Simulation is done by using DIgSILENT software on the part of the 20 kV real life Sirjan distribution system. In this article, optimum location with regard to system and environmental conditions are studied in two different viewpoints.

  20. Fundamental High-Speed Limits in Single-Molecule, Single-Cell, and Nanoscale Force Spectroscopies (United States)


    Force spectroscopy is enhancing our understanding of single-biomolecule, single-cell, and nanoscale mechanics. Force spectroscopy postulates the proportionality between the interaction force and the instantaneous probe deflection. By studying the probe dynamics, we demonstrate that the total force acting on the probe has three different components: the interaction, the hydrodynamic, and the inertial. The amplitudes of those components depend on the ratio between the resonant frequency and the frequency at which the data are measured. A force–distance curve provides a faithful measurement of the interaction force between two molecules when the inertial and hydrodynamic components are negligible. Otherwise, force spectroscopy measurements will underestimate the value of unbinding forces. Neglecting the above force components requires the use of frequency ratios in the 50–500 range. These ratios will limit the use of high-speed methods in force spectroscopy. The theory is supported by numerical simulations. PMID:27359243

  1. Towards lag phase of microbial populations at growth-limiting conditions: The role of the variability in the growth limits of individual cells. (United States)

    Aguirre, Juan S; Koutsoumanis, Konstantinos P


    The water activity (aw) growth limits of unheated and heat stressed Listeria monocytogenes individual cells were studied. The aw limits varied from 0.940 to 0.997 and 0.951 to 0.997 for unheated and heat stressed cells, respectively. Due to the above variability a decrease in aw results in the presence of a non-growing fraction in the population leading to an additional pseudo-lag in population growth. In this case the total apparent lag of the population is the sum of the physiological lag of the growing cells (time required to adjust to the new environment) and the pseudo-lag. To investigate the effect of aw on the above lag components, the growth kinetics of L. monocytogenes on tryptone soy agar with aw adjusted to values ranging from 0.997 to 0.940 was monitored. The model of B&R was fitted to the data for the estimation of the apparent lag. In order to estimate the physiological lag of the growing fraction of the inoculum, the model was refitted to the growth data using as initial population level the number of cells that were able to grow (estimated from the number of colonies formed on the agar at the end of storage) and excluding the rest data during the lag. The results showed that for the unheated cells the apparent lag was almost identical to the physiological lag for aw values ranging from 0.997 to 0.970, as the majority of the cells in the initial population was able to grow in these conditions. As the aw decreased from 0.970 to 0.940 however, the number of cells in the population which were able to grow, decreased resulting to an increase in the pseudo-lag. The maximum value of pseudo-lag was 13.1h and it was observed at aw=0.940 where 10% of the total inoculated cells were able to grow. For heat stressed populations a pseudo-lag started to increase at higher aw conditions (0.982) compared to unheated cells. In contrast to the apparent lag, a linear relation between physiological lag and aw was observed for both unheated and heat stressed cells.

  2. Superstrate Cu(In,Ga)Se2 Solar Cells: Prospects and Limitations (United States)

    Heinenann, Marc Daniel; Wollgarten, Markus; Unold, Thomas; Schock, Hans-Werner; Kaufmann, Christian


    Superstrate solar cell devices were prepared by thermal evaporation of the Cu(In,Ga)Se2 absorber material onto ZnO coated glass substrates. Photo-conversion efficiencies above 11% were reached by optimizing the deposition process. Interface analysis with electron microscopy and XPS measurements, combined with capacitance spectroscopy and device simulations, showed specific limitations of this device configurations, but also possible ways to overcome these. It was found that the GaOx, which forms at the CIGSe/ZnO interface during the absorber deposition process, reduces the interface recombination. At the same time it limits the efficiency due to its high density of negatively charged acceptor states which causes an electron barrier at the heterointerface. The required addition of sodium enhances the p-type doping of the absorber as normally observed, but also increases the net doping within the GaOx, which requires a tradeoff between these two effects. The devices were found to degrade over time, which is explained by field induced diffusion of positive cations out of the GaOx layer. This model is able to explain frequently observed effects upon light-soaking and forward-biasing of superstrate devices.

  3. Thoracic radiation therapy for limited-stage small-cell lung cancer: unanswered questions. (United States)

    Faivre-Finn, Corinne; Lorigan, Paul; West, Catharine; Thatcher, Nick


    The role of thoracic radiation therapy (RT; TRT) is now established in the management of limited-stage small-cell lung cancer (SCLC). There is increasing evidence in the literature in favor of early concurrent chemoradiation therapy, and a gold standard of care for patients with a good performance status is twice-daily TRT (45 Gy in 3 weeks) with concurrent cisplatin/etoposide. Five-year survival rates > 20% can be expected with this combined-modality approach. Although current clinical trials are exploring the efficacy of new chemotherapeutic strategies for the disease, essential questions related to the optimization of TRT remain unanswered. In particular, the optimal RT dose, fractionation, and treatment volume have not been defined. This review highlights the need for well-designed multinational trials aimed at the optimization and standardization of RT for limited-stage SCLC. These trials should integrate translational research studies to investigate the molecular basis of RT resistance and to develop biomarker profiles of prognosis.

  4. Subclassification of pulmonary non-small cell lung carcinoma in fine needle aspirates using a limited immunohistochemistry panel

    Directory of Open Access Journals (Sweden)

    Kusum Kapila


    Conclusion: Use of limited IHC panel helps categorize primary versus secondary tumors to the lung. The p63 is a useful marker for detecting squamous cell carcinoma. In countries where antibodies are not readily available, using a limited IHC panel of TTF-1, p63, and CK7 can help further type NSCLC lung tumors.

  5. Angular behavior of the absorption limit in thin film silicon solar cells

    CERN Document Server

    Naqavi, Ali; Söderström, Karin; Battaglia, Corsin; Paeder, Vincent; Scharf, Toralf; Herzig, Hans Peter; Ballif, Christophe


    We investigate the angular behavior of the upper bound of absorption provided by the guided modes in thin film solar cells. We show that the 4n^2 limit can be potentially exceeded in a wide angular and wavelength range using two-dimensional periodic thin film structures. Two models are used to estimate the absorption enhancement; in the first one, we apply the periodicity condition along the thickness of the thin film structure but in the second one, we consider imperfect confinement of the wave to the device. To extract the guided modes, we use an automatized procedure which is established in this work. Through examples, we show that from the optical point of view, thin film structures have a high potential to be improved by changing their shape. Also, we discuss the nature of different optical resonances which can be potentially used to enhance light trapping in the solar cell. We investigate the two different polarization directions for one-dimensional gratings and we show that the transverse magnetic pola...

  6. Statistical analysis of data from limiting dilution cloning to assess monoclonality in generating manufacturing cell lines. (United States)

    Quiroz, Jorge; Tsao, Yung-Shyeng


    Assurance of monoclonality of recombinant cell lines is a critical issue to gain regulatory approval in biological license application (BLA). Some of the requirements of regulatory agencies are the use of proper documentations and appropriate statistical analysis to demonstrate monoclonality. In some cases, one round may be sufficient to demonstrate monoclonality. In this article, we propose the use of confidence intervals for assessing monoclonality for limiting dilution cloning in the generation of recombinant manufacturing cell lines based on a single round. The use of confidence intervals instead of point estimates allow practitioners to account for the uncertainty present in the data when assessing whether an estimated level of monoclonality is consistent with regulatory requirements. In other cases, one round may not be sufficient and two consecutive rounds are required to assess monoclonality. When two consecutive subclonings are required, we improved the present methodology by reducing the infinite series proposed by Coller and Coller (Hybridoma 1983;2:91-96) to a simpler series. The proposed simpler series provides more accurate and reliable results. It also reduces the level of computation and can be easily implemented in any spreadsheet program like Microsoft Excel. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1061-1068, 2016.

  7. Limited genomic heterogeneity of circulating melanoma cells in advanced stage patients (United States)

    Ruiz, Carmen; Li, Julia; Luttgen, Madelyn S.; Kolatkar, Anand; Kendall, Jude T.; Flores, Edna; Topp, Zheng; Samlowski, Wolfram E.; McClay, Edward; Bethel, Kelly; Ferrone, Soldano; Hicks, James; Kuhn, Peter


    Purpose. Circulating melanoma cells (CMCs) constitute a potentially important representation of time-resolved tumor biology in patients. To date, genomic characterization of CMCs has been limited due to the lack of a robust methodology capable of identifying them in a format suitable for downstream characterization. Here, we have developed a methodology to detect intact CMCs that enables phenotypic, morphometric and genomic analysis at the single cell level. Experimental design. Blood samples from 40 metastatic melanoma patients and 10 normal blood donors were prospectively collected. A panel of 7 chondroitin sulfate proteoglycan 4 (CSPG4)-specific monoclonal antibodies (mAbs) was used to immunocytochemically label CMCs. Detection was performed by automated digital fluorescence microscopy and multi-parametric computational analysis. Individual CMCs were captured by micromanipulation for whole genome amplification and copy number variation (CNV) analysis. Results. Based on CSPG4 expression and nuclear size, 1-250 CMCs were detected in 22 (55%) of 40 metastatic melanoma patients (0.5-371.5 CMCs ml-1). Morphometric analysis revealed that CMCs have a broad spectrum of morphologies and sizes but exhibit a relatively homogeneous nuclear size that was on average 1.5-fold larger than that of surrounding PBMCs. CNV analysis of single CMCs identified deletions of CDKN2A and PTEN, and amplification(s) of TERT, BRAF, KRAS and MDM2. Furthermore, novel chromosomal amplifications in chr12, 17 and 19 were also found. Conclusions. Our findings show that CSPG4 expressing CMCs can be found in the majority of advanced melanoma patients. High content analysis of this cell population may contribute to the design of effective personalized therapies in patients with melanoma.

  8. Adult stem cells in neural repair: Current options, limitations and perspectives


    Mariano,Eric Domingos; Teixeira, Manoel Jacobsen; Marie, Suely Kazue Nagahashi; Lepski, Guilherme


    Stem cells represent a promising step for the future of regenerative medicine. As they are able to differentiate into any cell type, tissue or organ, these cells are great candidates for treatments against the worst diseases that defy doctors and researchers around the world. Stem cells can be divided into three main groups: (1) embryonic stem cells; (2) fetal stem cells; and (3) adult stem cells. In terms of their capacity for proliferation, stem cells are also classified as totipotent, plur...

  9. Limiting dilution analysis of alloantigen-reactive cells which respond to allogeneic lymphocytes in human MLC and PLT. (United States)

    Singal, D P; Naipaul, N; Joseph, S


    We have determined the frequency of the alloantigen-reactive cells (ARC) in human MLC and PLT by the limiting dilution analysis. In PLT, the frequency of the ARC to the original sensitizing donor ranged between 1:32 to 1:62, an increase of six to nine-fold after priming in MLC. The MLC primed populations were also enriched (three to five fold) for the ARC responding to the PL-positive allogeneic donors. The incidence of the ARC was 1:62 to 1:118 with donors positive for the sensitizing HLA-DRw antigen and 1:77 to 1:144 with donors negative for the specific HLA-DRw determinant. The results from experiments utilizing pooled stimulating cells from the original and allogeneic donors suggest that same subpopulation of cells responds to the sensitizing HLA-DRw determinant, whether it is presented by the specific stimulator or by a third-party allogeneic donor. On the other hand, different subpopulations of alloreactive cells respond to different alloantigens. In MLC experiments between HLA-identical siblings, the incidence of the ARC ranged between 1:995 to 1:1673. The responses of the ARC to non-HLA antigens were observed under conditions where responder cells were limiting. Also, the responses of the limiting numbers of responding cells were inhibited by mitomycin-treated autologous lymphocytes. Nonresponse in MLC combinations with higher responder cell numbers was not due to small numbers of stimulating cells.

  10. Exceeding the solar cell Shockley-Queisser limit via thermal up-conversion of low-energy photons (United States)

    Boriskina, Svetlana V.; Chen, Gang


    Maximum efficiency of ideal single-junction photovoltaic (PV) cells is limited to 33% (for 1 sun illumination) by intrinsic losses such as band edge thermalization, radiative recombination, and inability to absorb below-bandgap photons. This intrinsic thermodynamic limit, named after Shockley and Queisser (S-Q), can be exceeded by utilizing low-energy photons either via their electronic up-conversion or via the thermophotovoltaic (TPV) conversion process. However, electronic up-conversion systems have extremely low efficiencies, and practical temperature considerations limit the operation of TPV converters to the narrow-gap PV cells. Here we develop a conceptual design of a hybrid TPV platform, which exploits thermal up-conversion of low-energy photons and is compatible with conventional silicon PV cells by using spectral and directional selectivity of the up-converter. The hybrid platform offers sunlight-to-electricity conversion efficiency exceeding that imposed by the S-Q limit on the corresponding PV cells across a broad range of bandgap energies, under low optical concentration (1-300 suns), operating temperatures in the range 900-1700 K, and in simple flat panel designs. We demonstrate maximum conversion efficiency of 73% under illumination by non-concentrated sunlight. A detailed analysis of non-ideal hybrid platforms that allows for up to 15% of absorption/re-emission losses yields limiting efficiency value of 45% for Si PV cells.

  11. Intrinsic Constraint on Plasmablast Growth and Extrinsic Limits of Plasma Cell Survival



    B cells recruited into splenic antibody responses grow exponentially, either in extrafollicular foci as plasmablasts, or in follicles where they form germinal centers. Both responses yield plasma cells. Although many splenic plasma cells survive

  12. Comparison of dust charging between Orbital-Motion-Limited theory and Particle-In-Cell simulations

    CERN Document Server

    Delzanno, Gian Luca


    The Orbital-Motion-Limited (OML) theory has been modified to predict the dust charge and the results were contrasted with the Whipple approximation [Tang and Delzanno, Phys. Plasmas 21, 123708 (2014)]. To further establish its regime of applicability, in this paper the OML predictions (for a non-electron-emitting, spherical dust grain at rest in a collisionless, unmagnetized plasma) are compared with Particle-In-Cell simulations that retain the absorption radius effect. It is found that for large dust grain radius $r_d$ relative to the plasma Debye length $\\lambda_D$, the revised OML theory remains a very good approximation as, for the parameters considered ($r_d/\\lambda_D\\le10$, equal electron and ion temperatures), it yields the dust charge to within $20\\%$ accuracy. This is a substantial improvement over the Whipple approximation. The dust collected currents and energy fluxes, which remain the same in the revised and standard OML theories, are accurate to within $15-30\\%$.

  13. Limiting-dilution analysis for the determination of leukemic cell frequencies after bone marrow decontamination with mafosfamide or merocyanine 540

    Energy Technology Data Exchange (ETDEWEB)

    Porcellini, A.; Talevi, N.; Marchetti-Rossi, M.T.; Palazzi, M.; Manna, A.; Sparaventi, G.; Delfini, C.; Valentini, M.


    To stimulate a leukemia remission marrow, cell suspensions of normal human bone marrow were mixed with human acute lymphoblastic or myelogenous leukemic cells of the CCRF-SF, Nalm-6, and K-562 lines. The cell mixtures were incubated in vitro with mafosfamide (AZ) or with the photoreactive dye merocyanine 540 (MC-540). A quantity of 10(4) cells of the treated suspensions was dispensed into microculture plates, and graded cell numbers of the line used to contaminate the normal marrow were added. Limiting-dilution analysis was used to estimate the frequency of leukemia cells persisting after treatment with the decontaminating agents. Treatment with AZ or MC-540 produced a total elimination (ie, 6 logs or 5.3 logs respectively) of B cell acute leukemia cells (CCRF-SB), whereas nearly 1.7 logs and 2 logs of K-562 acute myelogenous blasts were still present in the cell mixtures after treatment with MC-540 and AZ, respectively. Treatment of the Nalm-6-contaminated cell mixtures with AZ resulted in 100% elimination of clonogenic cells, whereas nearly 80% decontamination was obtained with MC-540. Our results suggest that treatment with AZ could be an effective method of eliminating clonogenic tumor cells from human bone marrow. MC-540, shown by previous studies to spare sufficient pluripotential stem cells to ensure hemopoietic reconstitution in the murine model and in clinical application, has comparable effects and merits trials for possible clinical use in autologous bone marrow transplantation.

  14. CD73 is expressed by inflammatory Th17 cells in experimental autoimmune encephalomyelitis but does not limit differentiation or pathogenesis (United States)

    Hernandez-Mir, Gerard


    CD73 works together with CD39 to convert extracellular ATP to immunoregulatory adenosine, thus inhibiting inflammation. TGFβ-mediated CD73 expression on ‘regulatory’ Th17 cells limits their ability to eradicate tumors, similar to the immunosuppressive mechanism described for CD73 on Tregs. However, CD73 is also expressed on Th17 cells thought to be inflammatory in Crohn’s disease. CD73 has previously been reported to contribute to inflammation in the central nervous system (CNS). In experimental autoimmune encephalomyelitis (EAE), we found that inflammatory cytokine-producing Th17 cells showed increased CD73 expression as disease progressed. We therefore hypothesized that CD73 could be important for limiting the expansion or pathogenic function of Th17 cells in autoimmune inflammation of the CNS. Surprisingly, EAE development was not enhanced or inhibited by CD73 deficiency; there was correspondingly no difference in induction of Th17-associated cytokines IL-17, IFNγ or GM-CSF or recruitment of either inflammatory or regulatory cells to the central nervous system. We confirmed that CD73 was similarly not required for differentiation of Th17 cells in vitro. These data show that while CD73 expression is regulated during EAE, this enzyme is not absolutely required to either promote or limit Th17 cell expansion or EAE severity. PMID:28288184

  15. The cytokines interleukin 27 and interferon-γ promote distinct Treg cell populations required to limit infection-induced pathology. (United States)

    Hall, Aisling O'Hara; Beiting, Daniel P; Tato, Cristina; John, Beena; Oldenhove, Guillaume; Lombana, Claudia Gonzalez; Pritchard, Gretchen Harms; Silver, Jonathan S; Bouladoux, Nicolas; Stumhofer, Jason S; Harris, Tajie H; Grainger, John; Wojno, Elia D Tait; Wagage, Sagie; Roos, David S; Scott, Philip; Turka, Laurence A; Cherry, Sara; Reiner, Steven L; Cua, Daniel; Belkaid, Yasmine; Elloso, M Merle; Hunter, Christopher A


    Interferon-γ (IFN-γ) promotes a population of T-bet(+) CXCR3(+) regulatory T (Treg) cells that limit T helper 1 (Th1) cell-mediated pathology. Our studies demonstrate that interleukin-27 (IL-27) also promoted expression of T-bet and CXCR3 in Treg cells. During infection with Toxoplasma gondii, a similar population emerged that limitedcell responses and was dependent on IFN-γ in the periphery but on IL-27 at mucosal sites. Transfer of Treg cells ameliorated the infection-induced pathology observed in Il27(-/-) mice, and this was dependent on their ability to produce IL-10. Microarray analysis revealed that Treg cells exposed to either IFN-γ or IL-27 have distinct transcriptional profiles. Thus, IFN-γ and IL-27 have different roles in Treg cell biology and IL-27 is a key cytokine that promotes the development of Treg cells specialized to control Th1 cell-mediated immunity at local sites of inflammation.

  16. Intraclonal competition limits the fate determination of regulatory T cells in the thymus. (United States)

    Bautista, Jhoanne L; Lio, Chan-Wang J; Lathrop, Stephanie K; Forbush, Katherine; Liang, Yuqiong; Luo, Jingqin; Rudensky, Alexander Y; Hsieh, Chyi-Song


    Because the deletion of self-reactive T cells is incomplete, thymic development of natural Foxp3+CD4+ regulatory T cells (Treg cells) is required for preventing autoimmunity. However, the function of T cell antigen receptor (TCR) specificity in thymic Treg cell development remains controversial. To address this issue, we generated a transgenic line expressing a naturally occurring Treg cell-derived TCR. Unexpectedly, we found that efficient thymic Treg cell development occurred only when the antigen-specific Treg cell precursors were present at low clonal frequency (o1%) in a normal thymus. Using retroviral vectors and bone marrow chimeras, we observed similar activity with two other Treg cell-derived TCRs. Our data demonstrate that thymic Treg cell development is a 'TCR-instructive' process involving a niche that can be saturable at much lower clonal frequencies than is the niche for positive selection.

  17. Prospects and Limitations of Using Endogenous Neural Stem Cells for Brain Regeneration


    Kazunobu Sawamoto; Eisuke Kako; Naoko Kaneko


    Neural stem cells (NSCs) are capable of producing a variety of neural cell types, and are indispensable for the development of the mammalian brain. NSCs can be induced in vitro from pluripotent stem cells, including embryonic stem cells and induced-pluripotent stem cells. Although the transplantation of these exogenous NSCs is a potential strategy for improving presently untreatable neurological conditions, there are several obstacles to its implementation, including tumorigenic, immunologica...

  18. Collection-limited theory interprets the extraordinary response of single semiconductor organic solar cells. (United States)

    Ray, Biswajit; Baradwaj, Aditya G; Khan, Mohammad Ryyan; Boudouris, Bryan W; Alam, Muhammad Ashraful


    The bulk heterojunction (BHJ) organic photovoltaic (OPV) architecture has dominated the literature due to its ability to be implemented in devices with relatively high efficiency values. However, a simpler device architecture based on a single organic semiconductor (SS-OPV) offers several advantages: it obviates the need to control the highly system-dependent nanoscale BHJ morphology, and therefore, would allow the use of broader range of organic semiconductors. Unfortunately, the photocurrent in standard SS-OPV devices is typically very low, which generally is attributed to inefficient charge separation of the photogenerated excitons. Here we show that the short-circuit current density from SS-OPV devices can be enhanced significantly (∼100-fold) through the use of inverted device configurations, relative to a standard OPV device architecture. This result suggests that charge generation may not be the performance bottleneck in OPV device operation. Instead, poor charge collection, caused by defect-induced electric field screening, is most likely the primary performance bottleneck in regular-geometry SS-OPV cells. We justify this hypothesis by: (i) detailed numerical simulations, (ii) electrical characterization experiments of functional SS-OPV devices using multiple polymers as active layer materials, and (iii) impedance spectroscopy measurements. Furthermore, we show that the collection-limited photocurrent theory consistently interprets typical characteristics of regular SS-OPV devices. These insights should encourage the design and OPV implementation of high-purity, high-mobility polymers, and other soft materials that have shown promise in organic field-effect transistor applications, but have not performed well in BHJ OPV devices, wherein they adopt less-than-ideal nanostructures when blended with electron-accepting materials.

  19. Effect of early chemoradiotherapy in patients with limited stage small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Ha, In Bong; Jeong, Bae Kwon; Jeong, Ho Jin; Choi, Hoon Sik; Chai, Gyu Young; Kang, Myoung Hee; Kim, Hoon Gu; Lee, Gyeong Won; Na, Jae Beom; Kang, Ki Mun [Gyeongsang National University School of Medicine, Jinju (Korea, Republic of)


    We evaluated the effect of early chemoradiotherapy on the treatment of patients with limited stage small cell lung cancer (LS-SCLC). Between January 2006 and December 2011, thirty-one patients with histologically proven LS-SCLC who were treated with two cycles of chemotherapy followed by concurrent chemoradiotherapy and consolidation chemotherapy were retrospectively analyzed. The chemotherapy regimen was composed of etoposide and cisplatin. Thoracic radiotherapy consisted of 50 to 60 Gy (median, 54 Gy) given in 5 to 6.5 weeks. The follow-up period ranged from 5 to 53 months (median, 22 months). After chemoradiotherapy, 35.5% of the patients (11 patients) showed complete response, 61.3% (19 patients) showed partial response, 3.2% (one patient) showed progressive disease, resulting in an overall response rate of 96.8% (30 patients). The 1-, 2-, and 3-year overall survival (OS) rates were 66.5%, 41.0%, and 28.1%, respectively, with a median OS of 21.3 months. The 1-, 2-, and 3-year progression free survival (PFS) rates were 49.8%, 22.8%, and 13.7%, respectively, with median PFS of 12 months. The patterns of failure were: locoregional recurrences in 29.0% (nine patients), distant metastasis in 9.7% (three patients), and both locoregional and distant metastasis in 9.7% (three patients). Grade 3 or 4 toxicities of leukopenia, anemia, and thrombocytopenia were observed in 32.2%, 29.0%, and 25.8%, respectively. Grade 3 radiation esophagitis and radiation pneumonitis were shown in 12.9% and 6.4%, respectively. We conclude that early chemoradiotherapy for LS-SCLC provides feasible and acceptable local control and safety.

  20. Drosophila Boi limits Hedgehog levels to suppress follicle stem cell proliferation. (United States)

    Hartman, Tiffiney R; Zinshteyn, Daniel; Schofield, Heather K; Nicolas, Emmanuelle; Okada, Ami; O'Reilly, Alana M


    Stem cells depend on signals from cells within their microenvironment, or niche, as well as factors secreted by distant cells to regulate their maintenance and function. Here we show that Boi, a Hedgehog (Hh)-binding protein, is a novel suppressor of proliferation of follicle stem cells (FSCs) in the Drosophila ovary. Hh is expressed in apical cells, distant from the FSC niche, and diffuses to reach FSCs, where it promotes FSC proliferation. We show that Boi is expressed in apical cells and exerts its suppressive effect on FSC proliferation by binding to and sequestering Hh on the apical cell surface, thereby inhibiting Hh diffusion. Our studies demonstrate that cells distant from the local niche can regulate stem cell function through ligand sequestration, a mechanism that likely is conserved in other epithelial tissues.

  1. Cell death as a possible mechanism for tissue limited mosaicism in Pallister-Killian syndrome. (United States)

    Tang, Wozhan; Wenger, Sharon L


    Pallister-Killian syndrome is a chromosomal mosaic syndrome with a normal and an isochromosome 12p cell line, the latter rarely seen in peripheral blood. The isochromosome 12p cell line decreases with serial passages of fibroblasts in vitro and with age of patient in vivo. To evaluate cell death as a possible mechanism for loss of the abnormal cell line, amniocytes from a fetus with Pallister-Killian syndrome were identified as normal or aneuploid using a chromosome 12 alpha-satellite DNA probe by fluorescent in situ hybridization (FISH) and then subsequently stained with Annexin V, which stains the cytoplasm of cells that are dying. Although not conclusive, our preliminary results suggest that the abnormal cell line is going through apoptosis or necrosis at a higher rate than normal cells. Cell death may be a possible mechanism for decrease of the aneuploid cell line in patients with Pallister-Killian syndrome.

  2. Adult stem cells in neural repair: Current options, limitations and perspectives. (United States)

    Mariano, Eric Domingos; Teixeira, Manoel Jacobsen; Marie, Suely Kazue Nagahashi; Lepski, Guilherme


    Stem cells represent a promising step for the future of regenerative medicine. As they are able to differentiate into any cell type, tissue or organ, these cells are great candidates for treatments against the worst diseases that defy doctors and researchers around the world. Stem cells can be divided into three main groups: (1) embryonic stem cells; (2) fetal stem cells; and (3) adult stem cells. In terms of their capacity for proliferation, stem cells are also classified as totipotent, pluripotent or multipotent. Adult stem cells, also known as somatic cells, are found in various regions of the adult organism, such as bone marrow, skin, eyes, viscera and brain. They can differentiate into unipotent cells of the residing tissue, generally for the purpose of repair. These cells represent an excellent choice in regenerative medicine, every patient can be a donor of adult stem cells to provide a more customized and efficient therapy against various diseases, in other words, they allow the opportunity of autologous transplantation. But in order to start clinical trials and achieve great results, we need to understand how these cells interact with the host tissue, how they can manipulate or be manipulated by the microenvironment where they will be transplanted and for how long they can maintain their multipotent state to provide a full regeneration.

  3. Gastric LTi cells promote lymphoid follicle formation but are limited by IRAK-M and do not alter microbial growth. (United States)

    Shiu, J; Piazuelo, M B; Ding, H; Czinn, S J; Drakes, M L; Banerjee, A; Basappa, N; Kobayashi, K S; Fricke, W F; Blanchard, T G


    Lymphoid tissue inducer (LTi) cells are activated by accessory cell IL-23, and promote lymphoid tissue genesis and antibacterial peptide production by the mucosal epithelium. We investigated the role of LTi cells in the gastric mucosa in the context of microbial infection. Mice deficient in IRAK-M, a negative regulator of TLR signaling, were investigated for increased LTi cell activity, and antibody mediated LTi cell depletion was used to analyze LTi cell dependent antimicrobial activity. H. pylori infected IRAK-M deficient mice developed increased gastric IL-17 and lymphoid follicles compared to wild type mice. LTi cells were present in naive and infected mice, with increased numbers in IRAK-M deficient mice by two weeks. Helicobacter and Candida infection of LTi cell depleted rag1(-/-) mice demonstrated LTi-dependent increases in calprotectin but not RegIII proteins. However, pathogen and commensal microbiota populations remained unchanged in the presence or absence of LTi cell function. These data demonstrate LTi cells are present in the stomach and promote lymphoid follicle formation in response to infection, but are limited by IRAK-M expression. Additionally, LTi cell mediated antimicrobial peptide production at the gastric epithelium is less efficacious at protecting against microbial pathogens than has been reported for other tissues.

  4. Tim-3: An activation marker and activation limiter of innate immune cells

    Directory of Open Access Journals (Sweden)

    Gencheng eHan


    Full Text Available Tim-3 was initially identified on activated Th1, Th17, and Tc1 cells and induces T cell death or exhaustion after binding to its ligand, Gal-9. The observed relationship between dysregulated Tim-3 expression on T cells and the progression of many clinical diseases has identified this molecule as an important target for intervention in adaptive immunity. Recent data have shown that it also plays critical roles in regulating the activities of macrophages, monocytes, dendritic cells, mast cells, natural killer cells, and endothelial cells. Although the underlying mechanisms remain unclear, dysregulation of Tim-3 expression on these innate immune cells leads to an excessive or inhibited inflammatory response and subsequent autoimmune damage or viral or tumor evasion. In this review, we focus on the expression and function of Tim-3 on innate immune cells and discuss 1 how Tim-3 is expressed and regulated on different innate immune cells; 2 how it affects the activity of different innate immune cells; and 3 how dysregulated Tim-3 expression on innate immune cells affects adaptive immunity and disease progression. Tim-3 is involved in the optimal activation of innate immune cells through its varied expression. A better understanding of the physiopathological role of the Tim-3 pathway in innate immunity will shed new light on the pathogenesis of clinical diseases, such as autoimmune diseases, chronic viral infections, and cancer, and suggest new approaches to intervention.

  5. Tumor eradication after cyclophosphamide depends on concurrent depletion of regulatory T cells: a role for cycling TNFR2-expressing effector-suppressor T cells in limiting effective chemotherapy. (United States)

    van der Most, Robbert G; Currie, Andrew J; Mahendran, Sathish; Prosser, Amy; Darabi, Anna; Robinson, Bruce W S; Nowak, Anna K; Lake, Richard A


    Tumor cell death potentially engages with the immune system. However, the efficacy of anti-tumor chemotherapy may be limited by tumor-driven immunosuppression, e.g., through CD25+ regulatory T cells. We addressed this question in a mouse model of mesothelioma by depleting or reconstituting CD25+ regulatory T cells in combination with two different chemotherapeutic drugs. We found that the efficacy of cyclophosphamide to eradicate established tumors, which has been linked to regulatory T cell depletion, was negated by adoptive transfer of CD25+ regulatory T cells. Analysis of post-chemotherapy regulatory T cell populations revealed that cyclophosphamide depleted cycling (Ki-67(hi)) T cells, including foxp3+ regulatory CD4+ T cells. Ki-67(hi) CD4+ T cells expressed increased levels of two markers, TNFR2 and ICOS, that have been associated with a maximally suppressive phenotype according to recently published studies. This suggest that cyclophosphamide depletes a population of maximally suppressive regulatory T cells, which may explain its superior anti-tumor efficacy in our model. Our data suggest that regulatory T cell depletion could be used to improve the efficacy of anti-cancer chemotherapy regimens. Indeed, we observed that the drug gemcitabine, which does not deplete cycling regulatory T cells, eradicates established tumors in mice only when CD25+ CD4+ T cells are concurrently depleted. Cyclophosphamide could be used to achieve regulatory T cell depletion in combination with chemotherapy.

  6. Limited Restoration of Cystic Fibrosis Lung Epithelium In Vivo with Adult Bone Marrow–derived Cells


    Loi, Roberto; Beckett, Travis; Goncz, Kaarin K.; Suratt, Benjamin T.; Weiss, Daniel J.


    Rationale: Recent literature suggests that adult bone marrow–derived cells can localize to lung and acquire immunophenotypic characteristics of lung epithelial cells. We speculated this might be a potential therapeutic approach for correcting defective lung epithelium in cystic fibrosis.

  7. Antigen Export Reduces Antigen Presentation and Limits T Cell Control of M. tuberculosis. (United States)

    Srivastava, Smita; Grace, Patricia S; Ernst, Joel D


    Persistence of Mycobacterium tuberculosis results from bacterial strategies that manipulate host adaptive immune responses. Infected dendritic cells (DCs) transport M. tuberculosis to local lymph nodes but activate CD4 T cells poorly, suggesting bacterial manipulation of antigen presentation. However, M. tuberculosis antigens are also exported from infected DCs and taken up and presented by uninfected DCs, possibly overcoming this blockade of antigen presentation by infected cells. Here we show that the first stage of this antigen transfer, antigen export, benefits M. tuberculosis by diverting bacterial proteins from the antigen presentation pathway. Kinesin-2 is required for antigen export and depletion of this microtubule-based motor increases activation of antigen-specific CD4 T cells by infected cells and improves control of intracellular infection. Thus, although antigen transfer enables presentation by bystander cells, it does not compensate for reduced antigen presentation by infected cells and represents a bacterial strategy for CD4 T cell evasion.

  8. On the discharge capability and its limiting factors of commercial 18650 Li-ion cell at low temperatures (United States)

    Fan, Jiang

    We here study the discharge capability of commercial 18650 cylindrical lithium-ion cells at low temperatures. The discharge capacity at -20 °C ranges from 67 to 88% of the rated capacity at 0.2 C rate, which is good. However, the cell discharge capacity varies substantially at -30 and -40 °C among the studied cells. It ranges from 2 to 70% of the rated capacity at -30 °C, and 0 to 30% at -40 °C at 0.2 C rate. The cell impedance at 1 kHz increases very little from room temperature down to -20 or -30 °C in general, which does not correlate with the cell discharge capability. However, the dc impedance is increased by a factor of about ten at -30 °C and about twenty at -40 °C from room temperature. The discharge capability at low temperature correlates well with the dc resistance at both room and low temperatures. The limiting factors in the discharge capability at low temperatures and the direction for the future improvement are discussed according to the cell discharge capability, the electrode geometric area, the cell impedance at 1 kHz, and the dc impedance at various temperatures. It appears that the ionic conductivity of the electrolyte and lithium solid diffusion in the electrode do not limit the cell discharge capability, while the lithium diffusion in the SEI layer on the positive surface may be the limiting factor. Cell discharge capability at low temperature does not correlate with cycle life at room temperature.

  9. Adult stem cells in neural repair: Current options,limitations and perspectives

    Institute of Scientific and Technical Information of China (English)

    Eric Domingos Mariano; Manoel Jacobsen Teixeira; Suely Kazue Nagahashi Marie; Guilherme Lepski


    Stem cells represent a promising step for the future ofregenerative medicine. As they are able to differentiateinto any cell type, tissue or organ, these cells are greatcandidates for treatments against the worst diseasesthat defy doctors and researchers around the world.Stem cells can be divided into three main groups (1)embryonic stem cells; (2) fetal stem cells; and (3) adultstem cells. In terms of their capacity for proliferation,stem cells are also classified as totipotent, pluripotentor multipotent. Adult stem cells, also known as somaticcells, are found in various regions of the adult organism,such as bone marrow, skin, eyes, viscera and brain.They can differentiate into unipotent cells of theresiding tissue, generally for the purpose of repair.These cells represent an excellent choice in regenerativemedicine, every patient can be a donor of adult stemcells to provide a more customized and efficient therapyagainst various diseases, in other words, they allow theopportunity of autologous transplantation. But in orderto start clinical trials and achieve great results, we needto understand how these cells interact with the hosttissue, how they can manipulate or be manipulated bythe microenvironment where they will be transplantedand for how long they can maintain their multipotentstate to provide a full regeneration.

  10. Effect of glutamine limitation on the death of attached Chinese hamster ovary cells

    Energy Technology Data Exchange (ETDEWEB)

    Sanfeliu, A.; Stephanopoulos, G. (Massachusetts Inst. of Tech., Cambridge, MA (United States))


    The effect of glutamine depletion on the death of attached Chinese hamster ovary (CHO) cells was investigated. Experiments were performed using an anchorage dependent CHO cell line expressing [gamma]-IFN and a second cell line obtained by transfection of that cell line with the human bcl-2 (hbcl-2). Either cell line could grow in media devoid of glutamine with minimal cell death due to endogenous glutamine synthetase activity that allowed cells to synthesize glutamine from glutamic acid in the medium. However, compared to control cultures in glutamine-containing media, the cell growth rate in glutamine-free media was slower with an increased fraction of cells distributed in the G[sub 0]/G[sub 1] phase. The slower rate of cell cycling apparently protected the cells from entering apoptosis when they were stimulated to proliferate in an environment devoid of other protective factors, such as serum or over-expressed hbcl-2. The depletion of both glutamine and glutamic acid did cause cell death, which could be mitigated by hbcl-2 over-expression.

  11. Stem cells for clinical use in cardiovascular medicine: current limitations and future perspectives. (United States)

    Menasché, Philippe


    Cell transplantation is currently gaining a growing interest as a potential new means of improving the prognosis of patients with cardiac failure. The basic assumption is that left ventricular dysfunction is largely due to the loss of a critical number of cardiomyocytes and that it can be partly reversed by implantation of new contractile cells into the postinfarction scars. Primarily for practical reasons, autologous skeletal myoblasts have been the first to undergo clinical trials and now that the feasibility of the procedure is well established, efficacy data are expected from the ongoing randomized studies. Bone marrow stem cells are also generating a great deal of interest, particularly in patients with acute myocardial infarction, and are currently undergoing extensive clinical testing although recent data have raised a cautionary note about the transdifferentiation potential of these cells. While experimental studies and early-phase clinical trials tend to support the concept that cell therapy may enhance cardiac repair, several key issues still need to be addressed including (1) the optimal type of donor cells in relation to the clinical profile of the patients, (2) the mechanism by which cell engraftment improves cardiac function, (3) the optimization of cell survival, (4) the development of less invasive cell delivery techniques and (5) the potential benefits of cell transplantation in nonischemic heart failure. Current evidence suggests, however, that adult stem cells (myogenic or marrow-derived) fail to electromechanically integrate within the recipient heart, thereby mandating the search for second generation cell types able to achieve this goal which is the prerequisite for an effective enhancement of contractile function. Preliminary data suggest that cells that feature a true cardiomyogenic phenotype such as cardiac stem cells and cardiac-precommitted embryonic stem cells may fall in this category and carry the potential for ensuring a true

  12. Cell cycle phase expansion in nitrogen-limited cultures of Saccharomyces cerevisiae



    The time and coordination of cell cycle events were examined in the budding yeast Saccharomyces cerevisiae. Whole-cell autoradiographic techniques and time-lapse photography were used to measure the duration of the S, G1, and G2 phases, and the cell cycle positions of "start" and bud emergence, in cells whose growth rates were determined by the source of nitrogen. It was observed that the G1, S, and G2 phases underwent a proportional expansion with increasing cell cycle length, with the S pha...

  13. Prophylactic cranial irradiation in limited disease small-cell lung cancer in complete remission : a retrospective analysis

    NARCIS (Netherlands)

    van der Linden, YM; van Kempen, ML; van der Tweel, [No Value; Vanderschueren, RGJRA; Schlosser, JJ; Lammers, JWJ; Struikmans, H


    Recently a meta-analysis showed an improved survival probability of prophylactic cranial irradiation (PCI) in limited disease small-cell lung cancer (LD SCLC) in complete remission after chemotherapy. We evaluated treatment results of PCI+ and PCI- in these patients. Whether PCI (n = 65) or no PCI (

  14. Mechanisms limiting the performance of large grain polycrystalline silicon solar cells (United States)

    Culik, J. S.; Alexander, P.; Dumas, K. A.; Wohlgemuth, J. W.


    The open-circuit voltage and short-circuit current of large-grain (1 to 10 mm grain diameter) polycrystalline silicon solar cells is determined by the minority-carrier diffusion length within the bulk of the grains. This was demonstrated by irradiating polycrystalline and single-crystal (Czochralski) silicon solar cells with 1 MeV electrons to reduce their bulk lifetime. The variation of short-circuit current with minority-carrier diffusion length for the polycrystalline solar cells is identical to that of the single-crystal solar cells. The open-circuit voltage versus short-circuit current characteristic of the polycrystalline solar cells for reduced diffusion lengths is also identical to that of the single-crystal solar cells. The open-circuit voltage of the polycrystalline solar cells is a strong function of quasi-neutral (bulk) recombination, and is reduced only slightly, if at all, by grain-boundary recombination.

  15. Secretory expression of functional barley limit dextrinase by Pichia pastoris using high cell-density fermentation

    DEFF Research Database (Denmark)

    Vester-Christensen, Malene Bech; Abou Hachem, Maher; Næsted, Henrik


    Heterologous production of large multidomain proteins from higher plants is often cumbersome. Barley limit dextrinase (LD), a 98 kDa multidomain starch and alpha-limit dextrin debranching enzyme, plays a major role in starch mobilization during seed germination and is possibly involved in starch...

  16. The adaptor protein TRAF3 inhibits interleukin-6 receptor signaling in B cells to limit plasma cell development. (United States)

    Lin, Wai W; Yi, Zuoan; Stunz, Laura L; Maine, Christian J; Sherman, Linda A; Bishop, Gail A


    Tumor necrosis factor receptor-associated factor 3 (TRAF3) is an adaptor protein that inhibits signaling by CD40 and by the receptor for B cell-activating factor (BAFF) and negatively regulates homeostatic B cell survival. Loss-of-function mutations in TRAF3 are associated with human B cell malignancies, in particular multiple myeloma. The cytokine interleukin-6 (IL-6) supports the differentiation and survival of normal and neoplastic plasma cells. We found that mice with a deficiency in TRAF3 specifically in B cells (B-Traf3(-/-) mice) had about twice as many plasma cells as did their littermate controls. TRAF3-deficient B cells had enhanced responsiveness to IL-6, and genetic loss of IL-6 in B-Traf3(-/-) mice restored their plasma cell numbers to normal. TRAF3 inhibited IL-6 receptor (IL-6R)-mediated signaling by facilitating the association of PTPN22 (a nonreceptor protein tyrosine phosphatase) with the kinase Janus-activated kinase 1 (Jak1), which in turn blocked phosphorylation of the transcription factor STAT3 (signal transducer and activator of transcription 3). Consistent with these results, the number of plasma cells in the PTPN22-deficient mice was increased compared to that in the wild-type mice. Our findings identify TRAF3 and PTPN22 as inhibitors of IL-6R signaling in B cells and reveal a previously uncharacterized role for TRAF3 in the regulation of plasma cell differentiation.

  17. Hormone-sensitive lipase, the rate-limiting enzyme in triglyceride hydrolysis, is expressed and active in beta-cells. (United States)

    Mulder, H; Holst, L S; Svensson, H; Degerman, E; Sundler, F; Ahrén, B; Rorsman, P; Holm, C


    Triglycerides in the beta-cell may be important for stimulus-secretion coupling, through provision of a lipid-derived signal, and for pathogenetic events in NIDDM, where lipids may adversely affect beta-cell function. In adipose tissues, hormone-sensitive lipase (HSL) is rate-limiting in triglyceride hydrolysis. Here, we investigated whether this enzyme is also expressed and active in beta-cells. Northern blot analysis and reverse transcription-polymerase chain reaction demonstrated that HSL is expressed in rat islets and in the clonal beta-cell lines INS-1, RINm5F, and HIT-T15. Western blot analysis identified HSL in mouse and rat islets and the clonal beta-cells. In mouse and rat, immunocytochemistry showed a predominant occurrence of HSL in beta-cells, with a presumed cytoplasmic localization. Lipase activity in homogenates of the rodent islets and clonal beta-cells constituted 2.1 +/- 0.6% of that in adipocytes; this activity was immunoinhibited by use of antibodies to HSL. The established HSL expression and activity in beta-cells offer a mechanism whereby lipids are mobilized from intracellular stores. Because HSL in adipocytes is activated by cAMP-dependent protein kinase (PKA), PKA-regulated triglyceride hydrolysis in beta-cells may participate in the regulation of insulin secretion, possibly by providing a lipid-derived signal, e.g., long-chain acyl-CoA and diacylglycerol.

  18. Potential benefits and limitations of utilizing chondroprogenitors in cell-based cartilage therapy. (United States)

    Jayasuriya, Chathuraka T; Chen, Qian


    Chondroprogenitor cells are a subpopulation of multipotent progenitors that are primed for chondrogenesis. They are believed to have the biological repertoire to be ideal for cell-based cartilage therapy. In addition to summarizing recent advances in chondroprogenitor cell characterization, this review discusses the projected pros and cons of utilizing chondroprogenitors in regenerative medicine and compares them with that of pre-existing methods, including autologous chondrocyte implantation (ACI) and the utilization of bone marrow derived mesenchymal stem cells (MSCs) for the purpose of cartilage tissue repair.

  19. Comparative transcriptome analysis of embryonic and adult stem cells with extended and limited differentiation capacity (United States)

    Ulloa-Montoya, Fernando; Kidder, Benjamin L; Pauwelyn, Karen A; Chase, Lucas G; Luttun, Aernout; Crabbe, Annelies; Geraerts, Martine; Sharov, Alexei A; Piao, Yulan; Ko, Minoru SH; Hu, Wei-Shou; Verfaillie, Catherine M


    Background Recently, several populations of postnatal stem cells, such as multipotent adult progenitor cells (MAPCs), have been described that have broader differentiation ability than classical adult stem cells. Here we compare the transcriptome of pluripotent embryonic stem cells (ESCs), MAPCs, and lineage-restricted mesenchymal stem cells (MSCs) to determine their relationship. Results Applying principal component analysis, non-negative matrix factorization and k-means clustering algorithms to the gene-expression data, we identified a unique gene-expression profile for MAPCs. Apart from the ESC-specific transcription factor Oct4 and other ESC transcripts, some of them associated with maintaining ESC pluripotency, MAPCs also express transcripts characteristic of early endoderm and mesoderm. MAPCs do not, however, express Nanog or Sox2, two other key transcription factors involved in maintaining ESC properties. This unique molecular signature was seen irrespective of the microarray platform used and was very similar for both mouse and rat MAPCs. As MSC-like cells isolated under MAPC conditions are virtually identical to MSCs, and MSCs cultured in MAPC conditions do not upregulate MAPC-expressed transcripts, the MAPC signature is cell-type specific and not merely the result of differing culture conditions. Conclusion Multivariate analysis techniques clustered stem cells on the basis of their expressed gene profile, and the genes determining this clustering reflected the stem cells' differentiation potential in vitro. This comparative transcriptome analysis should significantly aid the isolation and culture of MAPCs and MAPC-like cells, and form the basis for studies to gain insights into genes that confer on these cells their greater developmental potency. PMID:17683608

  20. Multi-Cell MIMO Downlink with Cell Cooperation and Fair Scheduling: a Large-System Limit Analysis

    CERN Document Server

    Huh, Hoon; Moon, Sung-Hyun; Kim, Young-Tae; Lee, Inkyu


    We consider the downlink of a cellular network with multiple cells and multi-antenna base stations, including a realistic distance-dependent pathloss model, clusters of cooperating cells, and general "fairness" requirements. Beyond Monte Carlo simulation, no efficient computation method to evaluate the ergodic throughput of such systems has been presented so far. We propose an analytic solution based on the combination of large random matrix results and convex optimization. The proposed method is computationally much more efficient than Monte Carlo simulation and provides surprisingly accurate approximations for the actual finite-dimensional systems, even for a small number of users and base station antennas. Numerical examples include 2-cell linear and three-sectored 7-cell planar layouts, with no inter-cell cooperation, sector cooperation, or full inter-cell cooperation.

  1. Role of the p21 Cyclin-Dependent Kinase Inhibitor in Limiting Intimal Cell Proliferation in Response to Arterial Injury (United States)

    Yang, Zhi-Yong; Simari, Robert D.; Perkins, Neil D.; San, Hong; Gordon, David; Nabel, Gary J.; Nabel, Elizabeth G.


    Arterial injury induces a series of proliferative, vasoactive, and inflammatory responses that lead to vascular proliferative diseases, including atherosclerosis and restenosis. Although several factors have been defined which stimulate this process in vivo, the role of specific cellular gene products in limiting this response is not well understood. The p21 cyclin-dependent kinase inhibitor affects cell cycle progression, senescence, and differentiation in transformed cells, but its expression in injured blood vessels has not been investigated. In this study, we report that p21 protein is induced in porcine arteries following balloon catheter injury and suggest that p21 is likely to play a role in limiting arterial cell proliferation in vivo. Vascular endothelial and smooth muscle cell growth was arrested through the ability of p21 to inhibit progression through the G1 phase of the cell cycle. Following injury to porcine arteries, p21 gene product was detected in the neointima and correlated inversely with the location and kinetics of intimal cell proliferation. Direct gene transfer of p21 using an adenoviral vector into balloon injured porcine arteries inhibited the development of intimal hyperplasia. Taken together, these findings suggest that p21, and possibly related cyclin-dependent kinase inhibitors, may normally regulate cellular proliferation following arterial injury, and strategies to increase its expression may prove therapeutically beneficial in vascular diseases.

  2. An Electrochemical Impedance Study of the Capacity Limitations in Na–O2 Cells

    DEFF Research Database (Denmark)

    Knudsen, Kristian Bastholm; Nichols, Jessica E.; Vegge, Tejs


    Electrochemical impedance spectroscopy, pressure change measurements, and scanning electron microscopy were used to investigate the nonaqueous Na–O2 cell potential decrease and rise (sudden deaths) on discharge and charge, respectively. To fit the impedance spectra from operating cells, an equiva...

  3. Multi-cell MIMO Downlink with Fairness Criteria: the Large-System Limit

    CERN Document Server

    Huh, Hoon; Moon, Sung-Hyun; Lee, Inkyu


    We consider the downlink of a cellular network with multiple cells and multi-antenna base stations including arbitrary inter-cell cooperation, realistic distance-dependent pathloss and general "fairness" requirements. Beyond Monte Carlo simulation, no efficient computation method to evaluate the ergodic throughput of such systems has been provided so far. We propose a method based on the combination of some large random matrix results with Lagrangian optimization. The proposed method is computationally much more efficient than Monte Carlo simulation and provides a very accurate approximation (almost indistinguishable) for the actual finite-dimensional case, even for of a small number of user terminals and base station antennas. Numerical examples include a planar (two-dimensional) 7-cell layout, with no inter-cell cooperation, sector cooperation and full inter-cell cooperation.

  4. IKKα Promotes Intestinal Tumorigenesis by Limiting Recruitment of M1-like Polarized Myeloid Cells

    Directory of Open Access Journals (Sweden)

    Serkan I. Göktuna


    Full Text Available The recruitment of immune cells into solid tumors is an essential prerequisite of tumor development. Depending on the prevailing polarization profile of these infiltrating leucocytes, tumorigenesis is either promoted or blocked. Here, we identify IκB kinase α (IKKα as a central regulator of a tumoricidal microenvironment during intestinal carcinogenesis. Mice deficient in IKKα kinase activity are largely protected from intestinal tumor development that is dependent on the enhanced recruitment of interferon γ (IFNγ-expressing M1-like myeloid cells. In IKKα mutant mice, M1-like polarization is not controlled in a cell-autonomous manner but, rather, depends on the interplay of both IKKα mutant tumor epithelia and immune cells. Because therapies aiming at the tumor microenvironment rather than directly at the mutated cancer cell may circumvent resistance development, we suggest IKKα as a promising target for colorectal cancer (CRC therapy.

  5. [Possibilities and limits of paraffin-embedded cell markers in diagnosis of primary cutaneous histiocytosis]. (United States)

    Fartasch, M; Goerdt, S; Hornstein, O P


    To date, the rare primary histiocytoses of the skin are diagnosed definitively on the basis of the clinical symptoms, H&E-stained sections, and demonstration of CD1 positivity in frozen sections and of Birbeck granules on electron microscopy. The improvement and analysis of antibodies with the ability to react in paraffin tissue allow retrospective evaluation and classification of these disorders. The antibodies for S-100-protein, peanut agglutinin (PNA) and PCNA (proliferating cell nuclear antigen) have been advocated for differentiation of the specific cells of Langerhans cell histiocytosis (LCH) from other histiocytic cell systems. To date the non-Langerhans cell histiocytoses (non-LCH) have no common ultrastructural and immunohistochemical characteristics. The infiltrate is made up of multiple cell populations, which are of significance for the cellular pathobiology (subtypes of monocytes/macrophages and dendritic cells). The number and distribution of the different monocyte/macrophages and dendritic cells and their ability to react with immunohistochemical markers in paraffin tissue can be completely different in different clinical entities. The antibodies against factor XIIIa (shown on xanthoma disseminatum) and the monoclonal antibody Ki-M1P (shown on juvenile xanthogranuloma) seem to be valuable in discrimination between LCH and non-LCH. Both markers show a positive staining pattern with the characteristic large macrophages. In juvenile xanthogranuloma, the foam cells and giant cells express Ki-M1P, KP1 and anti-cathepsin B. Other monocyte/macrophage markers with the ability to react in paraffin tissue, such as Mac387, lysozyme, alpha 1-antitrypsin and Leu-M1 (Anti-CD 15), in contrast, did not show a typical staining pattern with the characteristic large macrophages dominating the histological picture.

  6. Limited Ca2+ and PKA-pathway dependent neurogenic differentiation of human adult mesenchymal stem cells as compared to fetal neuronal stem cells. (United States)

    Lepski, Guilherme; Jannes, Cinthia Elim; Maciaczyk, Jaroslaw; Papazoglou, Anna; Mehlhorn, Alexander T; Kaiser, Stefan; Teixeira, Manoel Jacobsen; Marie, Suely K N; Bischofberger, Josef; Nikkhah, Guido


    The ability of mesenchymal stem cells to generate functional neurons in culture is still a matter of controversy. In order to assess this issue, we performed a functional comparison between neuronal differentiation of human MSCs and fetal-derived neural stem cells (NSCs) based on morphological, immunocytochemical, and electrophysiological criteria. Furthermore, possible biochemical mechanisms involved in this process were presented. NF200 immunostaining was used to quantify the yield of differentiated cells after exposure to cAMP. The addition of a PKA inhibitor and Ca(2+) blockers to the differentiation medium significantly reduced the yield of differentiated cells. Activation of CREB was also observed on MSCs during maturation. Na(+)-, K(+)-, and Ca(2+)-voltage-dependent currents were recorded from MSCs-derived cells. In contrast, significantly larger Na(+) currents, firing activity, and spontaneous synaptic currents were recorded from NSCs. Our results indicate that the initial neuronal differentiation of MSCs is induced by cAMP and seems to be dependent upon Ca(2+) and the PKA pathway. However, compared to fetal neural stem cells, adult mesenchymal counterparts are limited in their neurogenic potential. Despite the similar yield of neuronal cells, NSCs achieved a more mature functional state. Description of the underlying mechanisms that govern MSCs' differentiation toward a stable neuronal phenotype and their limitations provides a unique opportunity to enhance our understanding of stem cell plasticity.

  7. Downregulation of the Werner syndrome protein induces a metabolic shift that compromises redox homeostasis and limits proliferation of cancer cells. (United States)

    Li, Baomin; Iglesias-Pedraz, Juan Manuel; Chen, Leng-Ying; Yin, Fei; Cadenas, Enrique; Reddy, Sita; Comai, Lucio


    The Werner syndrome protein (WRN) is a nuclear protein required for cell growth and proliferation. Loss-of-function mutations in the Werner syndrome gene are associated with the premature onset of age-related diseases. How loss of WRN limits cell proliferation and induces replicative senescence is poorly understood. Here, we show that WRN depletion leads to a striking metabolic shift that coordinately weakens the pathways that generate reducing equivalents for detoxification of reactive oxygen species and increases mitochondrial respiration. In cancer cells, this metabolic shift counteracts the Warburg effect, a defining characteristic of many malignant cells, resulting in altered redox balance and accumulation of oxidative DNA damage that inhibits cell proliferation and induces a senescence-like phenotype. Consistent with these findings, supplementation with antioxidant rescues at least in part cell proliferation and decreases senescence in WRN-knockdown cancer cells. These results demonstrate that WRN plays a critical role in cancer cell proliferation by contributing to the Warburg effect and preventing metabolic stress.

  8. Studies of Antibiotic Resistance of Beta-Lactamase Bacteria under Different Nutrition Limitations at the Single-Cell Level. (United States)

    Wang, Ying; Ran, Min; Wang, Jun; Ouyang, Qi; Luo, Chunxiong


    Drug resistance involves many biological processes, including cell growth, cell communication, and cell cooperation. In the last few decades, bacterial drug resistance studies have made substantial progress. However, a major limitation of the traditional resistance study still exists: most of the studies have concentrated on the average behavior of enormous amounts of cells rather than surveying single cells with different phenotypes or genotypes. Here, we report our study of beta-lactamase bacterial drug resistance in a well-designed microfluidic device, which allows us to conduct more controllable experiments, such as controlling the nutrient concentration, switching the culture media, performing parallel experiments, observing single cells, and acquiring time-lapse images. By using GFP as a beta-lactamase indicator and acquiring time-lapse images at the single-cell level, we observed correlations between the bacterial heterogeneous phenotypes and their behavior in different culture media. The feedback loop between the growth rate and the beta-lactamase production suggests that the beta-lactamase bacteria are more resistant in a rich medium than in a relatively poor medium. In the poorest medium, the proportion of dormant cells may increase, which causes a lower death rate in the same generation. Our work may contribute to assaying the antibiotic resistance of pathogenic bacteria in heterogeneous complex media.

  9. Parasitic worms stimulate host NADPH oxidases to produce reactive oxygen species that limit plant cell death and promote infection. (United States)

    Siddique, Shahid; Matera, Christiane; Radakovic, Zoran S; Hasan, M Shamim; Gutbrod, Philipp; Rozanska, Elzbieta; Sobczak, Miroslaw; Torres, Miguel Angel; Grundler, Florian M W


    Plants and animals produce reactive oxygen species (ROS) in response to infection. In plants, ROS not only activate defense responses and promote cell death to limit the spread of pathogens but also restrict the amount of cell death in response to pathogen recognition. Plants also use hormones, such as salicylic acid, to mediate immune responses to infection. However, there are long-lasting biotrophic plant-pathogen interactions, such as the interaction between parasitic nematodes and plant roots during which defense responses are suppressed and root cells are reorganized to specific nurse cell systems. In plants, ROS are primarily generated by plasma membrane-localized NADPH (reduced form of nicotinamide adenine dinucleotide phosphate) oxidases, and loss of NADPH oxidase activity compromises immune responses and cell death. We found that infection of Arabidopsis thaliana by the parasitic nematode Heterodera schachtii activated the NADPH oxidases RbohD and RbohF to produce ROS, which was necessary to restrict infected plant cell death and promote nurse cell formation. RbohD- and RbohF-deficient plants exhibited larger regions of cell death in response to nematode infection, and nurse cell formation was greatly reduced. Genetic disruption of SID2, which is required for salicylic acid accumulation and immune activation in nematode-infected plants, led to the increased size of nematodes in RbohD- and RbohF-deficient plants, but did not decrease plant cell death. Thus, by stimulating NADPH oxidase-generated ROS, parasitic nematodes fine-tune the pattern of plant cell death during the destructive root invasion and may antagonize salicylic acid-induced defense responses during biotrophic life stages.

  10. Limiting Current of Oxygen Reduction on Gas-Diffusion Electrodes for Phosphoric Acid Fuel Cells

    DEFF Research Database (Denmark)

    Li, Qingfeng; Gang, Xiao; Hjuler, Hans Aage;


    Various models have been devoted to the operation mechanism of porous diffusion electrodes. They are, however, suffering from the lack of accuracy concerning the acid-film thickness on which they are based. In the present paper the limiting current density has been measured for oxygen reduction...... on polytetrafluorine-ethyl bonded gas-diffusion electordes in phosphoric acid with and without fluorinated additives. This provides an alternative to estimate the film thickness by combining it with the acid-adsorption measurements and the porosity analysis of the catalyst layer. It was noticed that the limiting...... expression for the limiting current density. The acid-film thickness estimated this way was found to be of 0.1 mum order of magnitude for the two types of electrodes used in phosphoric acid with and without fluorinated additives at 150-degrees-C....

  11. NME2 reduces proliferation, migration and invasion of gastric cancer cells to limit metastasis.

    Directory of Open Access Journals (Sweden)

    Yan-fei Liu

    Full Text Available Gastric cancer is one of the most common malignancies and has a high rate of metastasis. We hypothesize that NME2 (Nucleoside Diphosphate Kinase 2, which has previously been considered as an anti-metastatic gene, plays a role in the invasiveness of gastric cancer cells. Using a tissue chip technology and immunohistochemistry, we demonstrated that NME2 expression was associated with levels of differentiation of gastric cancer cells and their metastasis into the lymph nodes. When the NME2 gene product was over-expressed by ;in vitro stable transfection, cells from BGC823 and MKN45 gastric cancer cell lines had reduced rates of proliferation, migration, and invasion through the collagen matrix, suggesting an inhibitory activity of NME2 in the propagation and invasion of gastric cancer. NME2 could, therefore, severe as a risk marker for gastric cancer invasiveness and a potential new target for gene therapy to enhance or induce NME2 expression.

  12. Asynchronous Inflammation and Myogenic Cell Migration Limit Muscle Tissue Regeneration Mediated by a Cellular Scaffolds (United States)


    over two-times that observed with muscle grafts, but they appeared to be less active, as gene expression of pro- and anti- inflammatory cytokines ( TNF -α...injury) the inflammatory and myogenic response to the muscle scaffold [16], which relies solely on host cell migration for regeneration [18]. Vital...cells [37] to induce myogenesis. Following injury, the type of the inflammatory response and the significance of transition from pro- to an anti

  13. Th2-polarized CD4+ T cells and macrophages limit efficacy of radiation therapy


    Shiao, Stephen L.; Ruffell, Brian; DeNardo, David G.; Faddegon, Bruce A; Park, Catherine C.; Coussens, Lisa M.


    Radiation therapy (RT) and chemotherapy (CTX) following surgery are mainstays of treatment for breast cancer (BC). While multiple studies have recently revealed the significance of immune cells as mediators of CTX response in BC, less is known regarding roles for leukocytes as mediating outcomes following RT. To address this, we utilized a syngeneic orthotopic murine model of mammary carcinogenesis to investigate if response to RT could be improved when select immune cells or immune-based pat...

  14. Solar Cell Temperature Dependent Efficiency and Very High Temperature Efficiency Limits



    Clean renewable solar energy is and will continue to be a critically important source of electrical energy. Solar energy has the potential of meeting all of the world's energy needs, and has seen substantial growth in recent years. Solar cells can convert sun light directly into electrical energy, and much progress has been made in making them less expensive and more efficient. Solar cells are often characterized and modeled at 25 °C, which is significantly lower than their peak operating tem...

  15. Limited clonal relatedness between gut IgA plasma cells and memory B cells after oral immunization. (United States)

    Bemark, Mats; Hazanov, Helena; Strömberg, Anneli; Komban, Rathan; Holmqvist, Joel; Köster, Sofia; Mattsson, Johan; Sikora, Per; Mehr, Ramit; Lycke, Nils Y


    Understanding how memory B cells are induced and relate to long-lived plasma cells is important for vaccine development. Immunity to oral vaccines has been considered short-lived because of a poor ability to develop IgA B-cell memory. Here we demonstrate that long-lived mucosal IgA memory is readily achieved by oral but not systemic immunization in mouse models with NP hapten conjugated with cholera toxin and transfer of B1-8(high)/GFP(+) NP-specific B cells. Unexpectedly, memory B cells are poorly related to long-lived plasma cells and less affinity-matured. They are α4β7-integrin(+)CD73(+)PD-L2(+)CD80(+) and at systemic sites mostly IgM(+), while 80% are IgA(+) in Peyer's patches. On reactivation, most memory B cells in Peyer's patches are GL7(-), but expand in germinal centres and acquire higher affinity and more mutations, demonstrating strong clonal selection. CCR9 expression is found only in Peyer's patches and appears critical for gut homing. Thus, gut mucosal memory possesses unique features not seen after systemic immunization.

  16. Phthalates Are Metabolised by Primary Thyroid Cell Cultures but Have Limited Influence on Selected Thyroid Cell Functions In Vitro

    DEFF Research Database (Denmark)

    Hansen, Juliana Frohnert; Brorson, Marianne Møller; Boas, Malene;


    in vitro studies within this area exist. The aim of the present study was to investigate the influence of three phthalate diesters (di-ethyl phthalate, di-n-butyl phthalate (DnBP), di-(2-ethylhexyl) phthalate (DEHP)) and two monoesters (mono-n-butyl phthalate and mono-(2-ethylhexyl) phthalate (MEHP......)) on the differentiated function of primary human thyroid cell cultures. Also, the kinetics of phthalate metabolism were investigated. DEHP and its monoester, MEHP, both had an inhibitory influence on 3'-5'-cyclic adenosine monophosphate secretion from the cells, and MEHP also on thyroglobulin (Tg) secretion from...... the cells. Results of the lactate dehydrogenase-measurements indicated that the MEHP-mediated influence was caused by cell death. No influence on gene expression of thyroid specific genes (Tg, thyroid peroxidase, sodium iodine symporter and thyroid stimulating hormone receptor) by any of the investigated...

  17. B cell-specific deficiencies in mTOR limit humoral immune responses. (United States)

    Zhang, Shuling; Pruitt, Margaret; Tran, Dena; Du Bois, Wendy; Zhang, Ke; Patel, Rushi; Hoover, Shelley; Simpson, R Mark; Simmons, John; Gary, Joy; Snapper, Clifford M; Casellas, Rafael; Mock, Beverly A


    Generation of high-affinity Abs in response to Ags/infectious agents is essential for developing long-lasting immune responses. B cell maturation and Ab responses to Ag stimulation require Ig somatic hypermutation (SHM) and class-switch recombination (CSR) for high-affinity responses. Upon immunization with either the model Ag 4-hydroxy-3-nitrophenylacetyl hapten (NP) conjugated to chicken γ globulin lysine (NP-CGG) or heat-killed Streptococcus pneumoniae capsular type 14 protein (Pn14), knock-in (KI) mice hypomorphic for mTOR function had a decreased ability to form germinal centers, develop high-affinity anti-NP-specific or anti-Pn14-specific Abs, and perform SHM/CSR. Hypomorphic mTOR mice also had a high mortality (40%) compared with wild-type (WT) (0%) littermates and had lower pneumococcal surface protein A-specific Ab titers when immunized and challenged with live S. pneumoniae infection. Mice with mTOR deleted in their B cell lineage (knockout [KO]) also produced fewer splenic germinal centers and decreased high-affinity Ab responses to NP-CGG than did their WT littermates. CSR rates were lower in mTOR KI and KO mice, and pharmacologic inhibition of mTOR in WT B cells resulted in decreased rates of ex vivo CSR. RNA and protein levels of activation-induced cytidine deaminase (AID), a protein essential for SHM and CSR, were lower in B cells from both KI and B cell-specific KO mice, concomitant with increases in phosphorylated AKT and FOXO1. Rescue experiments increasing AID expression in KI B cells restored CSR levels to those in WT B cells. Thus, mTOR plays an important immunoregulatory role in the germinal center, at least partially through AID signaling, in generating high-affinity Abs.

  18. Active enhancers are delineated de novo during hematopoiesis, with limited lineage fidelity among specified primary blood cells. (United States)

    Luyten, Annouck; Zang, Chongzhi; Liu, X Shirley; Shivdasani, Ramesh A


    Tissues may adopt diverse strategies to establish specific transcriptional programs in daughter lineages. In intestinal crypts, enhancers for genes expressed in both major cell types appear broadly permissive in stem and specified progenitor cells. In blood, another self-renewing tissue, it is unclear when chromatin becomes permissive for transcription of genes expressed in distinct terminal lineages. Using chromatin immunoprecipitation (ChIP) combined with deep sequencing (ChIP-seq) to profile activating histone marks, we studied enhancer dynamics in primary mouse blood stem, progenitor, and specified cells. Stem and multipotent progenitor cells show scant H3K4me2 marking at enhancers bound by specific transcription factors in their committed progeny. Rather, enhancers are modulated dynamically and serially, with substantial loss and gain of H3K4me2, at each cellular transition. Quantitative analysis of these dynamics accurately modeled hematopoiesis according to Waddington's notion of epigenotypes. Delineation of enhancers in terminal blood lineages coincides with cell specification, and enhancers active in single lineages show well-positioned H3K4me2- and H3K27ac-marked nucleosomes and DNaseI hypersensitivity in other cell types, revealing limited lineage fidelity. These findings demonstrate that enhancer chronology in blood cells differs markedly from that in intestinal crypts. Chromatin dynamics in hematopoiesis provide a useful foundation to consider classical observations such as cellular reprogramming and multilineage locus priming.

  19. Phthalates Are Metabolised by Primary Thyroid Cell Cultures but Have Limited Influence on Selected Thyroid Cell Functions In Vitro.

    Directory of Open Access Journals (Sweden)

    Juliana Frohnert Hansen

    Full Text Available Phthalates are plasticisers added to a wide variety of products, resulting in measurable exposure of humans. They are suspected to disrupt the thyroid axis as epidemiological studies suggest an influence on the peripheral thyroid hormone concentration. The mechanism is still unknown as only few in vitro studies within this area exist. The aim of the present study was to investigate the influence of three phthalate diesters (di-ethyl phthalate, di-n-butyl phthalate (DnBP, di-(2-ethylhexyl phthalate (DEHP and two monoesters (mono-n-butyl phthalate and mono-(2-ethylhexyl phthalate (MEHP on the differentiated function of primary human thyroid cell cultures. Also, the kinetics of phthalate metabolism were investigated. DEHP and its monoester, MEHP, both had an inhibitory influence on 3'-5'-cyclic adenosine monophosphate secretion from the cells, and MEHP also on thyroglobulin (Tg secretion from the cells. Results of the lactate dehydrogenase-measurements indicated that the MEHP-mediated influence was caused by cell death. No influence on gene expression of thyroid specific genes (Tg, thyroid peroxidase, sodium iodine symporter and thyroid stimulating hormone receptor by any of the investigated diesters could be demonstrated. All phthalate diesters were metabolised to the respective monoester, however with a fall in efficiency for high concentrations of the larger diesters DnBP and DEHP. In conclusion, human thyroid cells were able to metabolise phthalates but this phthalate-exposure did not appear to substantially influence selected functions of these cells.

  20. Microbial nar-GFP cell sensors reveal oxygen limitations in highly agitated and aerated laboratory-scale fermentors

    Directory of Open Access Journals (Sweden)

    Rao Govind


    Full Text Available Abstract Background Small-scale microbial fermentations are often assumed to be homogeneous, and oxygen limitation due to inadequate micromixing is often overlooked as a potential problem. To assess the relative degree of micromixing, and hence propensity for oxygen limitation, a new cellular oxygen sensor has been developed. The oxygen responsive E. coli nitrate reductase (nar promoter was used to construct an oxygen reporter plasmid (pNar-GFPuv which allows cell-based reporting of oxygen limitation. Because there are greater than 109 cells in a fermentor, one can outfit a vessel with more than 109 sensors. Our concept was tested in high density, lab-scale (5 L, fed-batch, E. coli fermentations operated with varied mixing efficiency – one verses four impellers. Results In both cases, bioreactors were maintained identically at greater than 80% dissolved oxygen (DO during batch phase and at approximately 20% DO during fed-batch phase. Trends for glucose consumption, biomass and DO showed nearly identical behavior. However, fermentations with only one impeller showed significantly higher GFPuv expression than those with four, indicating a higher degree of fluid segregation sufficient for cellular oxygen deprivation. As the characteristic time for GFPuv expression (approx 90 min. is much larger than that for mixing (approx 10 s, increased specific fluorescence represents an averaged effect of oxygen limitation over time and by natural extension, over space. Conclusion Thus, the pNar-GFPuv plasmid enabled bioreactor-wide oxygen sensing in that bacterial cells served as individual recirculating sensors integrating their responses over space and time. We envision cell-based oxygen sensors may find utility in a wide variety of bioprocessing applications.

  1. IRAK-M expression limits dendritic cell activation and proinflammatory cytokine production in response to Helicobacter pylori.

    Directory of Open Access Journals (Sweden)

    Jessica Shiu

    Full Text Available Helicobacter pylori (H. pylori infects the gastric mucosa and persists for the life of the host. Bacterial persistence may be due to the induction of regulatory T cells (Tregs whichmay have protective effects against other diseases such as asthma. It has been shown that H. pylori modulates the T cell response through dendritic cell reprogramming but the molecular pathways involved are relatively unknown. The goal of this study was to identify critical elements of dendritic cell (DC activation and evaluate potential influence on immune activation. Microarray analysis was used to demonstrate limited gene expression changes in H. pylori stimulated bone marrow derived DCs (BMDCs compared to the BMDCs stimulated with E. coli. IRAK-M, a negative regulator of TLR signaling, was upregulated and we selectedit for investigation of its role in modulating the DC and T cell responses. IRAK-M(-/- and wild type BMDC were compared for their response to H. pylori. Cells lacking IRAK-M produced significantly greater amounts of proinflammatory MIP-2 and reduced amounts of immunomodulatory IL-10 than wild type BMDC. IRAK-M(-/- cells also demonstrated increased MHC II expression upon activation. However, IRAK-M(-/- BMDCs were comparable to wild type BMDCs in inducing T-helper 17 (TH17 and Treg responses as demonstrated in vitro using BMDC CD4+ T cells co-culture assays,and in vivo though the adoptive transfer of CD4(+ FoxP3-GFP T cells into H. pylori infected IRAK-M(-/- mice. These results suggest that H. pylori infection leads to the upregulation of anti-inflammatory molecules like IRAK-M and that IRAK-M has a direct impact on innate functions in DCs such as cytokine and costimulation molecule upregulation but may not affect T cell skewing.

  2. On the Meaning of Affinity Limits in B-Cell Epitope Prediction for Antipeptide Antibody-Mediated Immunity

    Directory of Open Access Journals (Sweden)

    Salvador Eugenio C. Caoili


    Full Text Available B-cell epitope prediction aims to aid the design of peptide-based immunogens (e.g., vaccines for eliciting antipeptide antibodies that protect against disease, but such antibodies fail to confer protection and even promote disease if they bind with low affinity. Hence, the Immune Epitope Database (IEDB was searched to obtain published thermodynamic and kinetic data on binding interactions of antipeptide antibodies. The data suggest that the affinity of the antibodies for their immunizing peptides appears to be limited in a manner consistent with previously proposed kinetic constraints on affinity maturation in vivo and that cross-reaction of the antibodies with proteins tends to occur with lower affinity than the corresponding reaction of the antibodies with their immunizing peptides. These observations better inform B-cell epitope prediction to avoid overestimating the affinity for both active and passive immunization; whereas active immunization is subject to limitations of affinity maturation in vivo and of the capacity to accumulate endogenous antibodies, passive immunization may transcend such limitations, possibly with the aid of artificial affinity-selection processes and of protein engineering. Additionally, protein disorder warrants further investigation as a possible supplementary criterion for B-cell epitope prediction, where such disorder obviates thermodynamically unfavorable protein structural adjustments in cross-reactions between antipeptide antibodies and proteins.

  3. Modeling of electrode polarization for electrolytic cells with a limited ionic adsorption. (United States)

    Sawada, Atsushi


    Dilute electrolytic cells filled with chlorobenzene containing small amounts of tetrabutylammonium tetraphenylborate show anomalous dielectric dispersions in low-frequency regions. We propose a new model for electrode polarization in order to analyze the dielectric behavior of the dilute electrolytic cells. The model comprises two capacitive components: One is the space-charge polarization accompanied with a specific ionic adsorption on electrodes, and the other is the electrode capacitance which is brought about by an electronic spillover from the electrode surface. This model can primarily explain the anomalous frequency-dependent dielectric behavior of the electrolytic cells not only with low electrolyte concentrations, but also with high concentrations and can correctly describe the characteristics of the electrode polarization reflected in the dielectric spectra.

  4. Systematic repression of transcription factors reveals limited patterns of gene expression changes in ES cells (United States)

    Nishiyama, Akira; Sharov, Alexei A.; Piao, Yulan; Amano, Misa; Amano, Tomokazu; Hoang, Hien G.; Binder, Bernard Y.; Tapnio, Richard; Bassey, Uwem; Malinou, Justin N.; Correa-Cerro, Lina S.; Yu, Hong; Xin, Li; Meyers, Emily; Zalzman, Michal; Nakatake, Yuhki; Stagg, Carole; Sharova, Lioudmila; Qian, Yong; Dudekula, Dawood; Sheer, Sarah; Cadet, Jean S.; Hirata, Tetsuya; Yang, Hsih-Te; Goldberg, Ilya; Evans, Michele K.; Longo, Dan L.; Schlessinger, David; Ko, Minoru S. H.


    Networks of transcription factors (TFs) are thought to determine and maintain the identity of cells. Here we systematically repressed each of 100 TFs with shRNA and carried out global gene expression profiling in mouse embryonic stem (ES) cells. Unexpectedly, only the repression of a handful of TFs significantly affected transcriptomes, which changed in two directions/trajectories: one trajectory by the repression of either Pou5f1 or Sox2; the other trajectory by the repression of either Esrrb, Sall4, Nanog, or Tcfap4. The data suggest that the trajectories of gene expression change are already preconfigured by the gene regulatory network and roughly correspond to extraembryonic and embryonic fates of cell differentiation, respectively. These data also indicate the robustness of the pluripotency gene network, as the transient repression of most TFs did not alter the transcriptomes. PMID:23462645

  5. Thermodynamic efficiency limits of classical and bifacial multi-junction tandem solar cells: An analytical approach (United States)

    Alam, Muhammad Ashraful; Khan, M. Ryyan


    Bifacial tandem cells promise to reduce three fundamental losses (i.e., above-bandgap, below bandgap, and the uncollected light between panels) inherent in classical single junction photovoltaic (PV) systems. The successive filtering of light through the bandgap cascade and the requirement of current continuity make optimization of tandem cells difficult and accessible only to numerical solution through computer modeling. The challenge is even more complicated for bifacial design. In this paper, we use an elegantly simple analytical approach to show that the essential physics of optimization is intuitively obvious, and deeply insightful results can be obtained with a few lines of algebra. This powerful approach reproduces, as special cases, all of the known results of conventional and bifacial tandem cells and highlights the asymptotic efficiency gain of these technologies.

  6. Factors limiting the open-circuit voltage in microcrystalline silicon solar cells

    Directory of Open Access Journals (Sweden)

    Chatterjee P.


    Full Text Available In studying photovoltaic devices made with silicon thin films and considering them according to their grain size, it is curious that as the crystalline fraction increases, the open-circuit voltage (Voc – rather than approaching that of the single-crystal case – shows a decline. To gain an insight into this behavior, observed in hydrogenated microcrystalline silicon (μc-Si:H solar cells prepared under a variety of deposition conditions, we have used a detailed electrical-optical computer modeling program, ASDMP. Two typical μc-Si:H cells with low (~79% and higher (~93% crystalline volume fractions (Fc, deposited in our laboratory and showing this general trend, were modeled. From the parameters extracted by simulation of their experimental current density – voltage and quantum efficiency characteristics, it was inferred that the higher Fc cell has both a higher band gap defect density as well as a lower band gap energy. Our calculations reveal that the proximity of the quasi-Fermi levels to the energy bands in cells based on highly crystallized μc-Si:H (assumed to have a lower band gap, results in both higher free and trapped carrier densities. The trapped hole population, that is particularly high near the P/I interface, results in a strong interface field, a collapse of the field in the volume, and hence a lower open-circuit voltage. Interestingly enough, we were able to fabricate fluorinated μc-Si:H:F cells having 100% crystalline fraction as well as very large grains, that violate the general trend and show a higher Voc. Modeling indicates that this is possible for the latter case, as also for a crystalline silicon PN cell, in spite of a sharply reduced band gap, because the lower effective density of states at the band edges and a sharply reduced gap defect density overcome the effect of the lower band gap.

  7. Limited stage small cell carcinoma of the gastrointestinal tract: a clinicopathologic and prognostic analysis of 27 cases

    Directory of Open Access Journals (Sweden)

    Xiaoping Zou


    Full Text Available Small cell carcinoma of the gastrointestinal tract is a rare and aggressive neuroendocrine tumor. This study aims to analyze the clinical characteristics and potential prognostic factors for patients with limited stage small cell carcinoma of the gastrointestinal tract. The records of 27 patients with limited stage small cell carcinoma of the gastrointestinal tract, who all received surgery with lymphadenectomy, were retrieved and analyzed retrospectively. The median age of patients was 60 years old (range 38-79. The primary locations of tumor were the esophagus (74.1% and stomach (14.8%. The rate of preoperative accurate diagnosis (16.7% was low for small cell carcinoma of the esophagus and stomach. 40.7% of all the patients had regional lymph node metastases. Five patients underwent surgery alone, and the other 22 were treated with surgery + postoperative chemotherapy. All patients had disease progression or recurrence. The overall median survival time was 10 months and the 1-year survival rate was 37.0%. Patients who received postoperative chemotherapy had a median survival time of 12 months, which was superior to the 5-month survival of for those who only had surgery (P<0.0001. TNM stage (P=0.02 and postoperative chemotherapy (P<0.0001 were considered as two prognostic factors in univariate analysis. Postoperative chemotherapy was a significant independent prognostic factor in multivariate analysis (P=0.01. The prognosis for patients with limited stage small cell carcinoma of the gastrointestinal tract remains dismal, however, postoperative chemotherapy may have the potential to improve the outcome for these patients.

  8. On the performance limiting behavior of defect clusters in commercial silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B.L.; Chen, W.; Jones, K. [National Renewable Energy Lab., Golden, CO (United States); Gee, J. [Sandia National Labs., Albuquerque, NM (United States)


    The authors report the observation of defect clusters in high-quality, commercial silicon solar cell substrates. The nature of the defect clusters, their mechanism of formation, and precipitation of metallic impurities at the defect clusters are discussed. This defect configuration influences the device performance in a unique way--by primarily degrading the voltage-related parameters. Network modeling is used to show that, in an N/P junction device, these regions act as shunts that dissipate power generated within the cell.

  9. Three-dimensional limited-angle microtomography of blood cells: experimental results (United States)

    Levin, Gennady G.; Vishnyakov, Gennady N.; Zakarian, Constantin S.; Likhachov, Alexey V.; Pickalov, Valery V.; Kozinets, Gennady I.; Novoderzhkina, Julia K.; Streletskaya, Elena A.


    Tomographic measurements of the 3D refractive index spatial distribution within optically transparent phase samples with computerized interferometric microscopes are proposed. Phase shifting interferometric microtomography applications for the 3D image reconstruction of the blood cells are represented. The immersion 100x, N.A. equals 1.25 objective was used to increase the spatial resolution and observation angle range to 90 degree. ART, combined ART and iterative Gerchberg-Papoulis 3D algorithm were used for the tomogram reconstruction. To determine the accuracy and spatial resolution of the blood cells image reconstruction by means of the interferometric microtomographic method the numerical simulations were implemented.


    Hershey, A D; Bronfenbrenner, J


    1. Measurements of the rate of oxygen uptake per cell in transplants of Bacterium coli from cultures of this organism in different phases of growth have given results in essential agreement with the observations of others. 2. Correlations of viable count, centrifugable nitrogen, and turbidity, with oxygen consumption, indicate that the increased metabolism during the early portion of the growth period is quantitatively referable to increased average size of cells. 3. Indirect evidence has suggested that the initial rate of growth of transplants is not related to the phase of growth of the parent culture.

  11. Precursor limitations in methyl jasmonate-induced Catharanthus roseus cell cultures. (United States)

    Lee-Parsons, Carolyn W T; Royce, Amber J


    Jasmonates enhance the expression of various genes involved in terpenoid indole alkaloid (TIA) biosynthesis in Catharanthus roseus. We applied precursor feeding to our C. roseus suspensions to determine how methyl jasmonate (MJ) alters the precursor availability for TIA biosynthesis. C. roseus suspensions were induced with MJ (100 microM) on day 6 and fed loganin (0.30 mM), tryptamine (0.15 mM), loganin plus tryptamine, or geraniol (0.1-1.0 mM) on day 7. While MJ increased ajmalicine production by 3-fold, induced cultures were still limited by terpenoid precursors. However, both induced and non-induced cultures became tryptamine-limited with excess loganin. Geraniol feeding also increased ajmalicine production in non-induced cultures. But MJ appeared to increase geraniol availability in induced cultures, due presumably to the increased expression of Dxs with MJ addition.

  12. Pushing the Gradient Limitations of Superconducting Photonic Band Gap Structure Cells

    Energy Technology Data Exchange (ETDEWEB)

    Simakov, Evgenya I. [Los Alamos National Laboratory; Haynes, William B. [Los Alamos National Laboratory; Kurennoy, Sergey S. [Los Alamos National Laboratory; Shchegolkov, Dmitry [Los Alamos National Laboratory; O' Hara, James F. [Los Alamos National Laboratory; Olivas, Eric R. [Los Alamos National Laboratory


    Superconducting photonic band gap resonators present us with unique means to place higher order mode couples in an accelerating cavity and efficiently extract HOMs. An SRF PBG resonator with round rods was successfully tested at LANL demonstrating operation at 15 MV/m. Gradient in the SRF PBG resonator was limited by magnetic quench. To increase the quench threshold in PBG resonators one must design the new geometry with lower surface magnetic fields and preserve the resonator's effectiveness for HOM suppression. The main objective of this research is to push the limits for the high-gradient operation of SRF PBG cavities. A NCRF PBG cavity technology is established. The proof-of-principle operation of SRF PBG cavities is demonstrated. SRF PBG resonators are effective for outcoupling HOMs. PBG technology can significantly reduce the size of SRF accelerators and increase brightness for future FELs.

  13. Localization of type I interferon receptor limits interferon-induced TLR-3 in epithelial cells (United States)

    This study aimed to expand on the role of type I IFNs in the influenza-induced upregulation of TLR3 and determine whether and how the localization of the IFN-alpha/beta receptor (IFNAR) in respiratory epithelial cells could modify IFN-induced responses. Using differentiated prima...

  14. Conditioned Medium From Human Amniotic Mesenchymal Stromal Cells Limits Infarct Size and Enhances Angiogenesis

    NARCIS (Netherlands)

    Danieli, Patrizia; Malpasso, Giuseppe; Cluffreda, Maria Chiara; Cervio, Elisabetta; Calvillo, Laura; Copes, Francesco; Pisano, Federica; Mura, Manuela; Kleijn, Lennaert; de Boer, Rudolf A.; Viarengo, Gianluca; Rosti, Vittorio; Spinillo, Arsenio; Roccio, Marianna; Gnecchi, Massimiliano


    The paracrine properties of human amniotic membrane-derived mesenchymal stromal cells (hAMCs) have not been fully elucidated. The goal of the present study was to elucidate whether hAMCs can exert beneficial paracrine effects on infarcted rat hearts, in particular through cardioprotection and angiog

  15. Space-time adaptive ADER discontinuous Galerkin finite element schemes with a posteriori sub-cell finite volume limiting

    CERN Document Server

    Zanotti, Olindo; Dumbser, Michael; Hidalgo, Arturo


    In this paper we present a novel arbitrary high order accurate discontinuous Galerkin (DG) finite element method on space-time adaptive Cartesian meshes (AMR) for hyperbolic conservation laws in multiple space dimensions, using a high order \\aposteriori sub-cell ADER-WENO finite volume \\emph{limiter}. Notoriously, the original DG method produces strong oscillations in the presence of discontinuous solutions and several types of limiters have been introduced over the years to cope with this problem. Following the innovative idea recently proposed in \\cite{Dumbser2014}, the discrete solution within the troubled cells is \\textit{recomputed} by scattering the DG polynomial at the previous time step onto a suitable number of sub-cells along each direction. Relying on the robustness of classical finite volume WENO schemes, the sub-cell averages are recomputed and then gathered back into the DG polynomials over the main grid. In this paper this approach is implemented for the first time within a space-time adaptive ...

  16. Target cell APOBEC3C can induce limited G-to-A mutation in HIV-1.

    Directory of Open Access Journals (Sweden)

    Khaoula Bourara


    Full Text Available The evolutionary success of primate lentiviruses reflects their high capacity to mutate and adapt to new host species, immune responses within individual hosts, and, in recent years, antiviral drugs. APOBEC3G (A3G and APOBEC3F (A3F are host cell DNA-editing enzymes that induce extensive HIV-1 mutation that severely attenuates viral replication. The HIV-1 virion infectivity factor (Vif, expressed in vivo, counteracts the antiviral activity of A3G and A3F by inducing their degradation. Other APOBECs may contribute more to viral diversity by inducing less extensive mutations allowing viral replication to persist. Here we show that in APOBEC3C (A3C-expressing cells infected with the patient-derived HIV-1 molecular clones 210WW, 210WM, 210MW, and 210MM, and the lab-adapted molecular clone LAI, viral G-to-A mutations were detected in the presence of Vif expression. Mutations occurred primarily in the GA context and were relatively infrequent, thereby allowing for spreading infection. The mutations were absent in cells lacking A3C but were induced after transient expression of A3C in the infected target cell. Inhibiting endogenous A3C by RNA interference in Magi cells prevented the viral mutations. Thus, A3C is necessary and sufficient for G-to-A mutations in some HIV-1 strains. A3C-induced mutations occur at levels that allow replication to persist and may therefore contribute to viral diversity. Developing drugs that inhibit A3C may be a novel strategy for delaying viral escape from immune or antiretroviral inhibition.

  17. Target Cell APOBEC3C Can Induce Limited G-to-A Mutation in HIV-1 (United States)

    Bourara, Khaoula; Liegler, Teri J; Grant, Robert M


    The evolutionary success of primate lentiviruses reflects their high capacity to mutate and adapt to new host species, immune responses within individual hosts, and, in recent years, antiviral drugs. APOBEC3G (A3G) and APOBEC3F (A3F) are host cell DNA-editing enzymes that induce extensive HIV-1 mutation that severely attenuates viral replication. The HIV-1 virion infectivity factor (Vif), expressed in vivo, counteracts the antiviral activity of A3G and A3F by inducing their degradation. Other APOBECs may contribute more to viral diversity by inducing less extensive mutations allowing viral replication to persist. Here we show that in APOBEC3C (A3C)-expressing cells infected with the patient-derived HIV-1 molecular clones 210WW, 210WM, 210MW, and 210MM, and the lab-adapted molecular clone LAI, viral G-to-A mutations were detected in the presence of Vif expression. Mutations occurred primarily in the GA context and were relatively infrequent, thereby allowing for spreading infection. The mutations were absent in cells lacking A3C but were induced after transient expression of A3C in the infected target cell. Inhibiting endogenous A3C by RNA interference in Magi cells prevented the viral mutations. Thus, A3C is necessary and sufficient for G-to-A mutations in some HIV-1 strains. A3C-induced mutations occur at levels that allow replication to persist and may therefore contribute to viral diversity. Developing drugs that inhibit A3C may be a novel strategy for delaying viral escape from immune or antiretroviral inhibition. PMID:17967058

  18. Runx1 and p21 synergistically limit the extent of hair follicle stem cell quiescence in vivo. (United States)

    Lee, Jayhun; Hoi, Charlene S L; Lilja, Karin C; White, Brian S; Lee, Song Eun; Shalloway, David; Tumbar, Tudorita


    Mechanisms of tissue stem cell (SC) quiescence control are important for normal homeostasis and for preventing cancer. Cyclin-dependent kinase inhibitors (CDKis) are known inhibitors of cell cycle progression. We document CDKis expression in vivo during hair follicle stem cell (HFSC) homeostasis and find p21 (cyclin-dependent kinase inhibitor 1a, Cdkn1a), p57, and p15 up-regulated at quiescence onset. p21 appears important for HFSC timely onset of quiescence. Conversely, we find that Runx1 (runt related transcription factor 1), which is known for promoting HFSC proliferation, represses p21, p27, p57, and p15 transcription in HFSC in vivo. Intriguingly, in cell culture, tumors, and normal homeostasis, Runx1 and p21 interplay modulates proliferation in opposing directions under the different conditions. Unexpectedly, Runx1 and p21 synergistically limit the extent of HFSC quiescence in vivo, which antagonizes the role of p21 as a cell cycle inhibitor. Importantly, we find in cultured keratinocytes that Runx1 and p21 bind to the p15 promoter and synergistically repress p15 mRNA transcription, thereby restraining cell cycle arrest. This documents a surprising ability of a CDKi (p21) to act as a direct transcriptional repressor of another CDKi (p15). We unveil a robust in vivo mechanism that enforces quiescence of HFSCs, and a context-dependent role of a CDKi (p21) to limit quiescence of SCs, potentially by directly down-regulating mRNA levels of (an)other CDKi(s).

  19. Skin cell isolation and expansion for cell transplantation is limited in patients using tobacco, alcohol, or are exhibiting diabetes mellitus. (United States)

    Johnen, Christa; Hartmann, Bernd; Steffen, Ingo; Bräutigam, Kirsten; Witascheck, Tom; Toman, Nidal; Küntscher, Markus V; Gerlach, Jörg C


    The aim of this exploratory study was to investigate the isolation and expansion of keratinocytes and fibroblasts from donors with certain medical histories. Biopsies were taken from donors (N=32) falling into one or more of the following categories: a history of heavy smoking and/or alcohol abuse, drug abuse, diabetes mellitus or steroid treatment. Cells from donors who did not fall into any of the above-mentioned categories were used as controls. Proliferation and growth behaviour of cells were analyzed by measurement of passage duration, absorbance (MTT-assay) and light microscopy. Donors with a specific medical history required larger biopsy areas than the control group for isolating a sufficient number of fibroblasts and keratinocytes. Times to confluence were significantly prolonged and absorbances (MTT) were significantly reduced in several donor groups when compared to control cultures. Biopsies from donors with steroid treatment, drug abuse and combined nicotine and alcohol abuse could not be established beyond passage 0 degrees or 1 degree, respectively. We conclude that isolation and expansion of skin cells from donors with certain medical histories may require larger biopsies, prolonged expansion times or may even result in failure. These findings may therefore be of clinical importance in the field of autologous skin cell transplantation.

  20. Cell death induced by ozone and various non-thermal plasmas: therapeutic perspectives and limitations (United States)

    Lunov, Oleg; Zablotskii, Vitalii; Churpita, Olexander; Chánová, Eliška; Syková, Eva; Dejneka, Alexandr; Kubinová, Šárka


    Non-thermal plasma has been recognized as a promising tool across a vast variety of biomedical applications, with the potential to create novel therapeutic methods. However, the understanding of the molecular mechanisms behind non-thermal plasma cellular effects remains a significant challenge. In this study, we show how two types of different non-thermal plasmas induce cell death in mammalian cell cultures via the formation of multiple intracellular reactive oxygen/nitrogen species. Our results showed a discrepancy in the superoxide accumulation and lysosomal activity in response to air and helium plasma, suggesting that triggered signalling cascades might be grossly different between different plasmas. In addition, the effects of ozone, a considerable component of non-thermal plasma, have been simultaneously evaluated and have revealed much faster and higher cytotoxic effects. Our findings offer novel insight into plasma-induced cellular responses, and provide a basis for better controlled biomedical applications.

  1. CTR1 silencing inhibits angiogenesis by limiting copper entry into endothelial cells.

    Directory of Open Access Journals (Sweden)

    Gomathy Narayanan

    Full Text Available Increased levels of intracellular copper stimulate angiogenesis in human umbilical vein endothelial cells (HUVECs. Copper transporter 1 (CTR1 is a copper importer present in the cell membrane and plays a major role in copper transport. In this study, three siRNAs targeting CTR1 mRNA were designed and screened for gene silencing. HUVECs when exposed to 100 µM copper showed 3 fold increased proliferation, migration by 1.8-fold and tube formation by 1.8-fold. One of the designed CTR1 siRNA (si 1 at 10 nM concentration decreased proliferation by 2.5-fold, migration by 4-fold and tube formation by 2.8-fold. Rabbit corneal packet assay also showed considerable decrease in matrigel induced blood vessel formation by si 1 when compared to untreated control. The designed si 1 when topically applied inhibited angiogenesis. This can be further developed for therapeutic application.

  2. Comment on "Modeling of electrode polarization for electrolytic cells with a limited ionic adsorption". (United States)

    Alexe-Ionescu, A L; Barbero, G; Lelidis, I


    Recently, Sawada [Phys. Rev. E 88, 032406 (2013)] proposed a model to take into account the dielectric dispersion of ionic origin in a weak electrolyte cell. We first show that the model is based on questionable assumptions. Next, we point out an error in the author's calculation of the current in the external circuit. Finally, we demonstrate why some criticism on recent papers is irrelevant.

  3. Regenerative potential of the cartilaginous tissue in mesenchymal stem cells: update, limitations, and challenges. (United States)

    Cruz, Ivana Beatrice Mânica da; Severo, Antônio Lourenço; Azzolin, Verônica Farina; Garcia, Luiz Filipe Machado; Kuhn, André; Lech, Osvandré


    Advances in the studies with adult mesenchymal stem cells (MSCs) have turned tissue regenerative therapy into a promising tool in many areas of medicine. In orthopedics, one of the main challenges has been the regeneration of cartilage tissue, mainly in diarthroses. In the induction of the MSCs, in addition to cytodifferentiation, the microenvironmental context of the tissue to be regenerated and an appropriate spatial arrangement are extremely important factors. Furthermore, it is known that MSC differentiation is fundamentally determined by mechanisms such as cell proliferation (mitosis), biochemical-molecular interactions, movement, cell adhesion, and apoptosis. Although the use of MSCs for cartilage regeneration remains at a research level, there are important questions to be resolved in order to make this therapy efficient and safe. It is known, for instance, that the expansion of chondrocytes in cultivation, needed to increase the number of cells, could end up producing fibrocartilage instead of hyaline cartilage. However, the latest results are promising. In 2014, the first stage I/II clinical trial to evaluate the efficacy and safety of the intra-articular injection of MSCs in femorotibial cartilage regeneration was published, indicating a decrease in injured areas. One issue to be explored is how many modifications in the articulate inflammatory environment could induce differentiation of MSCs already allocated in that region. Such issue arose from studies that suggested that the suppression of the inflammation may increase the efficiency of tissue regeneration. Considering the complexity of the events related to the chondrogenesis and cartilage repair, it can be concluded that the road ahead is still long, and that further studies are needed.

  4. Semiconductor Nanowires: A Platform for Exploring Limits and Concepts for Nano-Enabled Solar Cells


    Kempa, Thomas Jan; Day, Robert Watson; Kim, Sun-Kyung; Park, Hong-Gyu; Lieber, Charles M.


    Over the past decade extensive studies of single semiconductor nanowire and nanowire array photovoltaic devices have explored the potential of these materials as platforms for a new generation of efficient and cost-effective solar cells. This feature review discusses strategies for implementation of semiconductor nanowires in solar energy applications, including advances in complex nanowire synthesis and characterization, fundamental insights from characterization of devices, utilization and ...

  5. Nutrient Regulation by Continuous Feeding Removes Limitations on Cell Yield in the Large-Scale Expansion of Mammalian Cell Spheroids


    Weegman, Bradley P; Peter Nash; Alexandra L Carlson; Kristin J Voltzke; Zhaohui Geng; Marjan Jahani; Benjamin B Becker; Papas, Klearchos K.; Firpo, Meri T.


    Cellular therapies are emerging as a standard approach for the treatment of several diseases. However, realizing the promise of cellular therapies across the full range of treatable disorders will require large-scale, controlled, reproducible culture methods. Bioreactor systems offer the scale-up and monitoring needed, but standard stirred bioreactor cultures do not allow for the real-time regulation of key nutrients in the medium. In this study, β-TC6 insulinoma cells were aggregated and cul...

  6. Establishing the limits of efficiency of perovskite solar cells from first principles modeling


    Oscar Grånäs; Dmitry Vinichenko; Efthimios Kaxiras


    The recent surge in research on metal-halide-perovskite solar cells has led to a seven-fold increase of efficiency, from similar to 3% in early devices to over 22% in research prototypes. Oft-cited reasons for this increase are: (i) a carrier diffusion length reaching hundreds of microns; (ii) a low exciton binding energy; and (iii) a high optical absorption coefficient. These hybrid organic-inorganic materials span a large chemical space with the perovskite structure. Here, using first-princ...

  7. Targeting host syntaxin-5 preferentially blocks Leishmania parasitophorous vacuole development in infected cells and limits experimental Leishmania infections. (United States)

    Canton, Johnathan; Kima, Peter E


    Our previous observations established a role for syntaxin-5 in the development of Leishmania parasitophorous vacuoles (LPVs). In this study, we took advantage of the recent identification of Retro-2, a small organic molecule that can cause the redistribution of syntaxin-5; we show herein that Retro-2 blocks LPV development within 2 hours of adding it to cells infected with Leishmania amazonensis. In infected cells incubated for 48 hours with Retro-2, LPV development was significantly limited; furthermore, infected cells harbored four to five times fewer parasites than infected cells incubated in vehicle alone. In vivo studies revealed that Retro-2 curbed experimental L. amazonensis infections in a dose-dependent manner. Retro-2 did not have any appreciable effect on the host cell physiological characteristics; furthermore, it had no apparent toxicity in experimental animals. An unexpected, but welcome, finding was that Retro-2 inhibited the replication of Leishmania parasites in axenic cultures. This study is significant because it identifies an endoplasmic reticulum/Golgi SNARE as a potential target for the control of Leishmania infections; moreover, it suggests that small organic molecules can be identified that can selectively disrupt the vesicle fusion machinery that promotes the development of pathogen-containing compartments without exerting toxic effects on the host.

  8. Prestin-driven cochlear amplification is not limited by the outer hair cell membrane time constant. (United States)

    Johnson, Stuart L; Beurg, Maryline; Marcotti, Walter; Fettiplace, Robert


    Outer hair cells (OHCs) provide amplification in the mammalian cochlea using somatic force generation underpinned by voltage-dependent conformational changes of the motor protein prestin. However, prestin must be gated by changes in membrane potential on a cycle-by-cycle basis and the periodic component of the receptor potential may be greatly attenuated by low-pass filtering due to the OHC time constant (τ(m)), questioning the functional relevance of this mechanism. Here, we measured τ(m) from OHCs with a range of characteristic frequencies (CF) and found that, at physiological endolymphatic calcium concentrations, approximately half of the mechanotransducer (MT) channels are opened at rest, depolarizing the membrane potential to near -40 mV. The depolarized resting potential activates a voltage-dependent K+ conductance, thus minimizing τ(m) and expanding the membrane filter so there is little receptor potential attenuation at the cell's CF. These data suggest that minimal τ(m) filtering in vivo ensures optimal activation of prestin.

  9. Exposure limits: the underestimation of absorbed cell phone radiation, especially in children. (United States)

    Gandhi, Om P; Morgan, L Lloyd; de Salles, Alvaro Augusto; Han, Yueh-Ying; Herberman, Ronald B; Davis, Devra Lee


    The existing cell phone certification process uses a plastic model of the head called the Specific Anthropomorphic Mannequin (SAM), representing the top 10% of U.S. military recruits in 1989 and greatly underestimating the Specific Absorption Rate (SAR) for typical mobile phone users, especially children. A superior computer simulation certification process has been approved by the Federal Communications Commission (FCC) but is not employed to certify cell phones. In the United States, the FCC determines maximum allowed exposures. Many countries, especially European Union members, use the "guidelines" of International Commission on Non-Ionizing Radiation Protection (ICNIRP), a non governmental agency. Radiofrequency (RF) exposure to a head smaller than SAM will absorb a relatively higher SAR. Also, SAM uses a fluid having the average electrical properties of the head that cannot indicate differential absorption of specific brain tissue, nor absorption in children or smaller adults. The SAR for a 10-year old is up to 153% higher than the SAR for the SAM model. When electrical properties are considered, a child's head's absorption can be over two times greater, and absorption of the skull's bone marrow can be ten times greater than adults. Therefore, a new certification process is needed that incorporates different modes of use, head sizes, and tissue properties. Anatomically based models should be employed in revising safety standards for these ubiquitous modern devices and standards should be set by accountable, independent groups.

  10. Asymptotic-Preserving Particle-In-Cell methods for the Vlasov-Maxwell system in the quasi-neutral limit (United States)

    Degond, P.; Deluzet, F.; Doyen, D.


    In this article, we design Asymptotic-Preserving Particle-In-Cell methods for the Vlasov-Maxwell system in the quasi-neutral limit, this limit being characterized by a Debye length negligible compared to the space scale of the problem. These methods are consistent discretizations of the Vlasov-Maxwell system which, in the quasi-neutral limit, remain stable and are consistent with a quasi-neutral model (in this quasi-neutral model, the electric field is computed by means of a generalized Ohm law). The derivation of Asymptotic-Preserving methods is not straightforward since the quasi-neutral model is a singular limit of the Vlasov-Maxwell model. The key step is a reformulation of the Vlasov-Maxwell system which unifies the two models in a single set of equations with a smooth transition from one to another. As demonstrated in various and demanding numerical simulations, the Asymptotic-Preserving methods are able to treat efficiently both quasi-neutral plasmas and non-neutral plasmas, making them particularly well suited for complex problems involving dense plasmas with localized non-neutral regions.

  11. Pivotal role of mouse mast cell protease 4 in the conversion and pressor properties of Big-endothelin-1. (United States)

    Houde, Martin; Jamain, Marc-David; Labonté, Julie; Desbiens, Louisane; Pejler, Gunnar; Gurish, Michael; Takai, Shinji; D'Orléans-Juste, Pedro


    The serine protease chymase has been reported to generate intracardiac angiotensin-II (Ang-II) from Ang-I as well as an intermediate precursor of endothelin-1 (ET-1), ET-1 (1-31) from Big-ET-1. Although humans possess only one chymase, several murine isoforms are documented, each with its own specific catalytic activity. Among these, mouse mast cell protease 4 (mMCP-4) is the isoform most similar to the human chymase for its activity. The aim of this study was to characterize the capacity of mMCP-4 to convert Big-ET-1 into its bioactive metabolite, ET-1, in vitro and in vivo in the mouse model. Basal mean arterial pressure did not differ between wild-type (WT) and mMCP-4(-/-) mice. Systemic administration of Big-ET-1 triggered pressor responses and increased blood levels of immunoreactive (IR) ET-1 (1-31) and ET-1 that were reduced by more than 50% in mMCP-4 knockout (-/-) mice compared with WT controls. Residual responses to Big-ET-1 in mMCP-4(-/-) mice were insensitive to the enkephalinase/neutral endopeptidase inhibitor thiorphan and the specific chymase inhibitor TY-51469 {2-[4-(5-fluoro-3-methylbenzo[b]thiophen-2-yl)sulfonamido-3-methanesulfonylphenyl]thiazole-4-carboxylic acid}. Soluble fractions from the lungs, left cardiac ventricle, aorta, and kidneys of WT but not mMCP-4(-/-) mice generated ET-1 (1-31) from exogenous Big-ET-1 in a TY-51469-sensitive fashion as detected by high-performance liquid chromatography/ matrix-assisted laser desorption/ionization-mass spectrometry. Finally, pulmonary endogenous levels of IR-ET-1 were reduced by more than 40% in tissues derived from mMCP-4(-/-) mice compared with WT mice. Our results show that mMCP-4 plays a pivotal role in the dynamic conversion of systemic Big-ET-1 to ET-1 in the mouse model.

  12. Gold Nanoparticles Promote Proliferation of Human Periodontal Ligament Stem Cells and Have Limited Effects on Cells Differentiation

    Directory of Open Access Journals (Sweden)

    Chen Li


    Full Text Available Gold nanoparticles (AuNPs had been widely applied in the practice and advancement of chemistry, biology, and medicine due to facility of synthesis and versatility in surface functionalization. Recent studies had shown that AuNPs can be applied to cells, affecting cellular physiological processes such as proliferation and differentiation. In this study, four diameters of AuNPs (20, 40, 60, and 80 nm were cocultured with human periodontal ligament cells (hPDLCs at six different concentrations. The optimal size and concentration of AuNPs were selected to treat human periodontal ligament stem cells (hPDLSCs to evaluate proliferation. Moreover, the influence of AuNPs on multiple differentiation capacity of hPDLSCs was clarified. The results revealed that AuNPs (60 nm, 56 μM can effectively promote the proliferation of hPDLCs/hPDLSCs in vitro, slightly enhance osteoblastic differentiation, and have no effect on adipogenic differentiation. In addition, the expression of COL-1, Runx2, BSP, and OCN was upregulated in the presence of AuNPs (60 nm, 56 μM. These results indicated that AuNPs (60 nm, 56 μM can effectively promote the proliferation of hPDLCs/hPDLSCs and have no significant effect on the differentiation of hPDLSCs. These results provide an insight on the advantage of implementing of AuNPs on hPDLSCs culture and expose the influence of these materials on periodontal tissue engineering.

  13. Prognostic Limitations of Donor T Cell Chimerism after Myeloablative Allogeneic Stem Cell Transplantation for Acute Myeloid Leukemia and Myelodysplastic Syndromes. (United States)

    Wong, Eric; Mason, Kate; Collins, Jenny; Hockridge, Barbara; Boyd, Janis; Gorelik, Alexandra; Szer, Jeffrey; Ritchie, David S


    Donor T cell chimerism is associated with relapse outcomes after allogeneic stem cell transplantation (alloSCT) for acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS). However, measures of statistical association do not adequately assess the performance of a prognostic biomarker, which is best characterized by its sensitivity and specificity for the chosen outcome. We analyzed donor T cell chimerism results at day 100 (D100chim) after myeloablative alloSCT for AML or MDS in 103 patients and determined its sensitivity and specificity for relapse-free survival at 6 months (RFS6) and 12 months (RFS12) post-alloSCT. The area under the receiver operating characteristic curve for RFS6 was .68, demonstrating only modest utility as a predictive biomarker, although this was greater than RFS12 at .62. Using a D100chim threshold of 65%, the specificity for RFS6 was 96.6%; however, sensitivity was poor at 26.7%. This equated to a negative predictive value of 88.5% and positive predictive value of 57.1%. Changing the threshold for D100chim to 75% or 85% modestly improved the sensitivity of D100chim for RFS6; however, this was at the expense of specificity. D100chim is specific but lacks sensitivity as a prognostic biomarker of early RFS after myeloablative alloSCT for AML or MDS. Caution is required when using D100chim to guide treatment decisions including immunologic manipulation, which may expose patients to unwarranted graft-versus-host disease.


    Directory of Open Access Journals (Sweden)

    Majid Sadeqzadeh


    Full Text Available In this study, the effect of different electrode surface areas on the performance of dual chamber Microbial Fuel Cells (MFC was investigated. Four different electrodes with 12, 16, 20 and 24 cm2 surface areas were tested in an MFC system. The 20 cm2 electrode generated an output power of 76.5 mW/m2 was found to be the highest among all the electrodes tested. This might be due to better interactions with microorganism and less mass transfer limitation. In addition, this indicates that the chances for attachment of bacteria and generation of electricity in larger electrode surface areas might be limited by mass transport and by higher surface area. The output power generation was then followed by the 16, 12 and 24 cm2 electrodes which generated 69.6, 64.7 and 61.25 mW/m2 electricity, respectively.

  15. Scaling-up of membraneless microbial electrolysis cells (MECs) for domestic wastewater treatment: Bottlenecks and limitations. (United States)

    Escapa, A; San-Martín, M I; Mateos, R; Morán, A


    Microbial electrolysis cells (MECs) have the potential to become a sustainable domestic wastewater (dWW) treatment system. However, new scale-up experiences are required to gain knowledge of critical issues in MEC designs. In this study we assess the ability of two twin membraneless MEC units (that are part of a modular pilot-scale MEC) to treat dWW. Batch tests yielded COD removal efficiencies as high as 92%, with most of the hydrogen (>80% of the total production) being produced during the first 48h. During the continuous tests, MECs performance deteriorated significantly (energy consumption was relatively high and COD removal efficiencies fell below 10% in many cases), which was attributed to an inadequate configuration of the anodic chamber, insufficient mixing inside this chamber, inefficient hydrogen management on the cathode side and finally to dWW in itself. Some alternatives to the current design are suggested.

  16. Thin Silicon Solar Cells: A Path to 35% Shockley-Queisser Limits

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Laura; Boccard, Mathieu; Williams, Joshua; Jeffries, April; Gangam, Srikanth; Ghosh, Kunal; Honsberg, Christiana; Bowden, Stuart; Holman, Zachary; Atwater, Harry; Buonassisi, Tonio; Bremner, Stephen; Green, Martin; Balif, Christoph; Bertoni, Mariana


    Crystalline silicon technology is expected to remain the leading photovoltaic industry workhorse for decades. We present here the objectives and workplan of a recently launched project funded by the U.S. Department of Energy through the Foundational Program to Advance Cell Efficiency II (FPACE II), which aims at leading crystalline silicon to an efficiency breakthrough. The project will tackle fundamental approach of materials design, defect engineering, device simulations and materials growth and characterization. Among the main novelties, the implementation of carrier selective contacts made of wide bandgap material or stack of materials is investigated for improved passivation, carrier extraction and carrier transport. Based on an initial selection of candidate materials, preliminary experiments are conducted to verify the suitability of their critical parameters as well as preservation of the silicon substrate surface and bulk properties. The target materials include III-V and metal-oxide materials.

  17. Hyperbolic divergence cleaning, the electrostatic limit, and potential boundary conditions for particle-in-cell codes (United States)

    Pfeiffer, M.; Munz, C.-D.; Fasoulas, S.


    In a numerical solution of the Maxwell-Vlasov system, the consistency with the charge conservation and divergence conditions has to be kept solving the hyperbolic evolution equations of the Maxwell system, since the vector identity ∇ ṡ (∇ × u →) = 0 and/or the charge conservation of moving particles may be not satisfied completely due to discretization errors. One possible method to force the consistency is the hyperbolic divergence cleaning. This hyperbolic constraint formulation of Maxwell's equations has been proposed previously, coupling the divergence conditions to the hyperbolic evolution equations, which can then be treated with the same numerical method. We pick up this method again and show that electrostatic limit may be obtained by accentuating the divergence cleaning sub-system and converging to steady state. Hence, the electrostatic case can be treated by the electrodynamic code with reduced computational effort. In addition, potential boundary conditions as often given in practical applications can be coupled in a similar way to get appropriate boundary conditions for the field equations. Numerical results are shown for an electric dipole, a parallel-plate capacitor, and a Langmuir wave. The use of potential boundary conditions is demonstrated in an Einzel lens simulation.

  18. Benefits and Limitations of Protein Hydrolysates as Components of Serum-Free Media for Animal Cell Culture Applications (United States)

    Lobo-Alfonso, Juliet; Price, Paul; Jayme, David

    Increased understanding of influential factors for the cultivation of animal cells, combined with heightened regulatory concern over potential transmission of adventitious contaminants associated with serum and other animal-derived components, has elevated interest in using protein hydrolysates as serum replacements or nutrient supplements. This paper reviews the chemistry and biology of various hydrolysates derived from animal, plant and microbial sources. It provides specific examples of a beneficial selection of plant and yeast hydrolysates as ingredients of serum-free nutrient formulations for bioproduction applications of cultured mammalian and insect cells. Strategies for customizing and optimizing nutrients for specialized applications and general benefits and limitations of protein hydrolysates for biopharmaceutical production are also discussed.

  19. Igs Expressed by Chronic Lymphocytic Leukemia B Cells Show Limited Binding-Site Structure Variability

    KAUST Repository

    Marcatili, P.


    Ag selection has been suggested to play a role in chronic lymphocytic leukemia (CLL) pathogenesis, but no large-scale analysis has been performed so far on the structure of the Ag-binding sites (ABSs) of leukemic cell Igs. We sequenced both H and L chain V(D)J rearrangements from 366 CLL patients and modeled their three-dimensional structures. The resulting ABS structures were clustered into a small number of discrete sets, each containing ABSs with similar shapes and physicochemical properties. This structural classification correlates well with other known prognostic factors such as Ig mutation status and recurrent (stereotyped) receptors, but it shows a better prognostic value, at least in the case of one structural cluster for which clinical data were available. These findings suggest, for the first time, to our knowledge, on the basis of a structural analysis of the Ab-binding sites, that selection by a finite quota of antigenic structures operates on most CLL cases, whether mutated or unmutated. Copyright © 2013 by The American Association of Immunologists, Inc.

  20. Autophagy Limits Endotoxemic Acute Kidney Injury and Alters Renal Tubular Epithelial Cell Cytokine Expression. (United States)

    Leventhal, Jeremy S; Ni, Jie; Osmond, Morgan; Lee, Kyung; Gusella, G Luca; Salem, Fadi; Ross, Michael J


    Sepsis related acute kidney injury (AKI) is a common in-hospital complication with a dismal prognosis. Our incomplete understanding of disease pathogenesis has prevented the identification of hypothesis-driven preventive or therapeutic interventions. Increasing evidence in ischemia-reperfusion and nephrotoxic mouse models of AKI support the theory that autophagy protects renal tubular epithelial cells (RTEC) from injury. However, the role of RTEC autophagy in septic AKI remains unclear. We observed that lipopolysaccharide (LPS), a mediator of gram-negative bacterial sepsis, induces RTEC autophagy in vivo and in vitro through TLR4-initiated signaling. We modeled septic AKI through intraperitoneal LPS injection in mice in which autophagy-related protein 7 was specifically knocked out in the renal proximal tubules (ATG7KO). Compared to control littermates, ATG7KO mice developed more severe renal dysfunction (24hr BUN 100.1mg/dl +/- 14.8 vs 54.6mg/dl +/- 11.3) and parenchymal injury. After injection with LPS, analysis of kidney lysates identified higher IL-6 expression and increased STAT3 activation in kidney lysates from ATG7KO mice compared to controls. In vitro experiments confirmed an altered response to LPS in RTEC with genetic or pharmacological impairment of autophagy. In conclusion, RTEC autophagy protects against endotoxin induced injury and regulates downstream effects of RTEC TLR4 signaling.

  1. Autophagy Limits Endotoxemic Acute Kidney Injury and Alters Renal Tubular Epithelial Cell Cytokine Expression.

    Directory of Open Access Journals (Sweden)

    Jeremy S Leventhal

    Full Text Available Sepsis related acute kidney injury (AKI is a common in-hospital complication with a dismal prognosis. Our incomplete understanding of disease pathogenesis has prevented the identification of hypothesis-driven preventive or therapeutic interventions. Increasing evidence in ischemia-reperfusion and nephrotoxic mouse models of AKI support the theory that autophagy protects renal tubular epithelial cells (RTEC from injury. However, the role of RTEC autophagy in septic AKI remains unclear. We observed that lipopolysaccharide (LPS, a mediator of gram-negative bacterial sepsis, induces RTEC autophagy in vivo and in vitro through TLR4-initiated signaling. We modeled septic AKI through intraperitoneal LPS injection in mice in which autophagy-related protein 7 was specifically knocked out in the renal proximal tubules (ATG7KO. Compared to control littermates, ATG7KO mice developed more severe renal dysfunction (24hr BUN 100.1mg/dl +/- 14.8 vs 54.6mg/dl +/- 11.3 and parenchymal injury. After injection with LPS, analysis of kidney lysates identified higher IL-6 expression and increased STAT3 activation in kidney lysates from ATG7KO mice compared to controls. In vitro experiments confirmed an altered response to LPS in RTEC with genetic or pharmacological impairment of autophagy. In conclusion, RTEC autophagy protects against endotoxin induced injury and regulates downstream effects of RTEC TLR4 signaling.

  2. Limited impact of total parenteral nutrition on nutritional status during treatment for small cell lung cancer. (United States)

    Evans, W K; Makuch, R; Clamon, G H; Feld, R; Weiner, R S; Moran, E; Blum, R; Shepherd, F A; Jeejeebhoy, K N; DeWys, W D


    During a randomized trial of total parenteral nutrition (TPN) in patients with small cell lung cancer, we evaluated the short- and long-term effects of 4 weeks of TPN on nutritional assessment parameters. All 119 patients who were accrued to the study received the same chemotherapy and radiotherapy protocol which extended over a 1-year period: 57 patients received TPN; and 62 served as controls. At base line, patients with greater than 5% pretreatment weight loss had significantly lower levels of serum albumin, total iron-binding capacity, and creatinine/height index. TPN administration led to a significant increase in mean caloric intake and weight compared with controls (P less than 0.0001). In the short-term study, body fat, as measured by triceps skinfold thickness, was maintained, and there was a small increase in arm muscle circumference. Serum albumin and hematocrit decreased but promptly returned to pretreatment levels when TPN was stopped. There were no long-term differences in any of the nutritional assessment parameters between the two groups.

  3. α-Lipoic acid antioxidant treatment limits glaucoma-related retinal ganglion cell death and dysfunction. (United States)

    Inman, Denise M; Lambert, Wendi S; Calkins, David J; Horner, Philip J


    Oxidative stress has been implicated in neurodegenerative diseases, including glaucoma. However, due to the lack of clinically relevant models and expense of long-term testing, few studies have modeled antioxidant therapy for prevention of neurodegeneration. We investigated the contribution of oxidative stress to the pathogenesis of glaucoma in the DBA/2J mouse model of glaucoma. Similar to other neurodegenerative diseases, we observed lipid peroxidation and upregulation of oxidative stress-related mRNA and protein in DBA/2J retina. To test the role of oxidative stress in disease progression, we chose to deliver the naturally occurring, antioxidant α-lipoic acid (ALA) to DBA/2J mice in their diet. We used two paradigms for ALA delivery: an intervention paradigm in which DBA/2J mice at 6 months of age received ALA in order to intervene in glaucoma development, and a prevention paradigm in which DBA/2J mice were raised on a diet supplemented with ALA, with the goal of preventing glaucoma development. At 10 and 12 months of age (after 4 and 11 months of dietary ALA respectively), we measured changes in genes and proteins related to oxidative stress, retinal ganglion cell (RGC) number, axon transport, and axon number and integrity. Both ALA treatment paradigms showed increased antioxidant gene and protein expression, increased protection of RGCs and improved retrograde transport compared to control. Measures of lipid peroxidation, protein nitrosylation, and DNA oxidation in retina verified decreased oxidative stress in the prevention and intervention paradigms. These data demonstrate the utility of dietary therapy for reducing oxidative stress and improving RGC survival in glaucoma.

  4. Dicarboxylic acids with limited numbers of hydrocarbons stabilize cell membrane and increase osmotic resistance in rat erythrocytes. (United States)

    Mineo, Hitoshi; Amita, Nozomi; Kawawake, Megumi; Higuchi, Ayaka


    We examined the effect of dicarboxylic acids having 0 to 6 hydrocarbons and their corresponding monocarboxylic or tricarboxylic acids in changing the osmotic fragility (OF) in rat red blood cells (RBCs). Malonic, succinic, glutaric and adipic acids, which are dicarboxylic acids with 1, 2, 3 and 4 straight hydrocarbons located between two carboxylic groups, decreased the OF in a concentration-dependent manner. Other long-chain dicarboxylic acids did not change the OF in rat RBCs. The benzoic acid derivatives, isophthalic and terephthalic acids, but not phthalic acid, decreased the OF in a concentration-dependent manner. Benzene-1,2,3-tricarboxylic acid, but not benzene-1,3,5-tricarboxylic acid, also decreased the OF in rat RBCs. On the other hand, monocarboxylic acids possessing 2 to 7 straight hydrocarbons and benzoic acid increased the OF in rat RBCs. In short-chain dicarboxylic acids, a limited number of hydrocarbons between the two carboxylic groups are thought to form a V- or U-shaped structure and interact with phospholipids in the RBC membrane. In benzene dicarboxylic and tricarboxylic acids, a part of benzene nucleus between the two carboxylic groups is thought to enter the plasma membrane and act on acyl-chain in phospholipids in the RBC membrane. For dicarboxylic and tricarboxylic acids, limited numbers of hydrocarbons in molecules are speculated to enter the RBC membrane with the hydrophilic carboxylic groups remaining outside, stabilizing the structure of the cell membrane and resulting in an increase in osmotic resistance in rat RBCs.

  5. Study of quality and field limitation of superconducting 1.3 GHz 9-Cell RF-cavities at DESY

    Energy Technology Data Exchange (ETDEWEB)

    Schlander, Felix


    The European XFEL and the International Linear Collider are based on superconducting rf cavities made of niobium. Their advantages are low ohmic losses which allow high duty cycles and the possibility to use a large beam aperture which is substantial to prevent wake fields at high current accelerators. To reach the theoretical limits of superconducting cavities, it is required to understand the present performance limitations. These are field emission, thermal breakdown (quench) and the ohmic losses dependent on the accelerating field, which are expressed in the quality factor. As the limiting mechanisms themselves are understood in general, the origin of the quench is often unclear. To determine the quench locations, a localisation tool for thermal breakdown using the second sound in superfluid helium has been installed at the cavity test facility at DESY and the results for a sample of about 30 cavities have been examined. The features of the distribution of the quench locations have been analysed and it has been found that the quench locations are in the area of the highest surface magnetic field and not necessarily at the equator of the cells. The data sample has been extended in an attempt to characterise the average behaviour of the quality factor related to the accelerating field. An analysis of the surface resistance of individual cavities shows that a recently developed model for the surface resistance of niobium is not able to describe the measurement in all detail, but the application of an additional mechanism showed promising results.

  6. Overcoming the Range Limitation of Medium-Duty Battery Electric Vehicles through the use of Hydrogen Fuel-Cells

    Energy Technology Data Exchange (ETDEWEB)

    Wood, E.; Wang, L.; Gonder, J.; Ulsh, M.


    Battery electric vehicles possess great potential for decreasing lifecycle costs in medium-duty applications, a market segment currently dominated by internal combustion technology. Characterized by frequent repetition of similar routes and daily return to a central depot, medium-duty vocations are well positioned to leverage the low operating costs of battery electric vehicles. Unfortunately, the range limitation of commercially available battery electric vehicles acts as a barrier to widespread adoption. This paper describes the National Renewable Energy Laboratory's collaboration with the U.S. Department of Energy and industry partners to analyze the use of small hydrogen fuel-cell stacks to extend the range of battery electric vehicles as a means of improving utility, and presumably, increasing market adoption. This analysis employs real-world vocational data and near-term economic assumptions to (1) identify optimal component configurations for minimizing lifecycle costs, (2) benchmark economic performance relative to both battery electric and conventional powertrains, and (3) understand how the optimal design and its competitiveness change with respect to duty cycle and economic climate. It is found that small fuel-cell power units provide extended range at significantly lower capital and lifecycle costs than additional battery capacity alone. And while fuel-cell range-extended vehicles are not deemed economically competitive with conventional vehicles given present-day economic conditions, this paper identifies potential future scenarios where cost equivalency is achieved.

  7. Current Treatment Limitations in Age-Related Macular Degeneration and Future Approaches Based on Cell Therapy and Tissue Engineering

    Directory of Open Access Journals (Sweden)

    P. Fernández-Robredo


    Full Text Available Age-related macular degeneration (AMD is the leading cause of blindness in the Western world. With an ageing population, it is anticipated that the number of AMD cases will increase dramatically, making a solution to this debilitating disease an urgent requirement for the socioeconomic future of the European Union and worldwide. The present paper reviews the limitations of the current therapies as well as the socioeconomic impact of the AMD. There is currently no cure available for AMD, and even palliative treatments are rare. Treatment options show several side effects, are of high cost, and only treat the consequence, not the cause of the pathology. For that reason, many options involving cell therapy mainly based on retinal and iris pigment epithelium cells as well as stem cells are being tested. Moreover, tissue engineering strategies to design and manufacture scaffolds to mimic Bruch’s membrane are very diverse and under investigation. Both alternative therapies are aimed to prevent and/or cure AMD and are reviewed herein.

  8. Immunosurveillance function of human mast cell?

    Institute of Scientific and Technical Information of China (English)

    (O)ner (O)zdemir


    Mast cell (MC) is so widely recognized as a critical effector in allergic disorders that it can be difficult to think of MC in any other context. Indeed, MCs are multifunctional and recently shown that MCs can also act as antigen presenters as well as effector elements of human immune system. First observations of their possible role as anti-tumor cells in peri- or intra-tumoral tissue were mentioned five decades ago and a high content of MCs is considered as a favorable prognosis,consistent with this study. Believers of this hypothesis assumed them to be inhibitors of tumor development through their pro-apoptotic and -necrolytic granules e.g.,granzymes and TNF-α. However, some still postulate them to be enhancers of tumor development through their effects on angiogenesis due to mostly tryptase.There are also some data suggesting increased MC density causes tumor development and indicates bad prognosis. Furthermore, since MC-associated mediators have shown to influence various aspects of tumor biology, the net effect of MCs on the development/progression of tumors has been difficult to evaluate. For instance, chymase induces apoptosis in targets; yet,tryptase, another MC protease, is a well-known mitogen.MCs with these various enzyme expression patterns may mediate different functions and the predominant MC type in tissues may be determined by the environmental needs. The coexistence of tryptase-expressing MCs(MCT) and chymase and tryptase-expressing MCs (MCTC)in physiological conditions reflects a naturally occurring balance that contributes to tissue homeostasis. We have recently discussed the role and relevance of MC serine proteases in different bone marrow diseases.

  9. Computational Model Reveals Limited Correlation between Germinal Center B-Cell Subclone Abundancy and Affinity: Implications for Repertoire Sequencing (United States)

    Reshetova, Polina; van Schaik, Barbera D. C.; Klarenbeek, Paul L.; Doorenspleet, Marieke E.; Esveldt, Rebecca E. E.; Tak, Paul-Peter; Guikema, Jeroen E. J.; de Vries, Niek; van Kampen, Antoine H. C.


    Immunoglobulin repertoire sequencing has successfully been applied to identify expanded antigen-activated B-cell clones that play a role in the pathogenesis of immune disorders. One challenge is the selection of the Ag-specific B cells from the measured repertoire for downstream analyses. A general feature of an immune response is the expansion of specific clones resulting in a set of subclones with common ancestry varying in abundance and in the number of acquired somatic mutations. The expanded subclones are expected to have BCR affinities for the Ag higher than the affinities of the naive B cells in the background population. For these reasons, several groups successfully proceeded or suggested selecting highly abundant subclones from the repertoire to obtain the Ag-specific B cells. Given the nature of affinity maturation one would expect that abundant subclones are of high affinity but since repertoire sequencing only provides information about abundancies, this can only be verified with additional experiments, which are very labor intensive. Moreover, this would also require knowledge of the Ag, which is often not available for clinical samples. Consequently, in general we do not know if the selected highly abundant subclone(s) are also the high(est) affinity subclones. Such knowledge would likely improve the selection of relevant subclones for further characterization and Ag screening. Therefore, to gain insight in the relation between subclone abundancy and affinity, we developed a computational model that simulates affinity maturation in a single GC while tracking individual subclones in terms of abundancy and affinity. We show that the model correctly captures the overall GC dynamics, and that the amount of expansion is qualitatively comparable to expansion observed from B cells isolated from human lymph nodes. Analysis of the fraction of high- and low-affinity subclones among the unexpanded and expanded subclones reveals a limited correlation between

  10. Assaying embryotoxicity in the test tube: current limitations of the embryonic stem cell test (EST) challenging its applicability domain. (United States)

    Riebeling, Christian; Hayess, Katrin; Peters, Annelieke K; Steemans, Margino; Spielmann, Horst; Luch, Andreas; Seiler, Andrea E M


    Testing for embryotoxicity in vitro is an attractive alternative to animal experimentation. The embryonic stem cell test (EST) is such a method, and it has been formally validated by the European Centre for the Validation of Alternative Methods. A number of recent studies have underscored the potential of this method. However, the EST performed well below the 78% accuracy expected from the validation study using a new set of chemicals and pharmaceutical compounds, and also of toxicity criteria, tested to enlarge the database of the validated EST as part of the Work Package III of the ReProTect Project funded within the 6th Framework Programme of the European Union. To assess the performance and applicability domain of the EST we present a detailed review of the substances and their effects in the EST being nitrofen, ochratoxin A, D-penicillamine, methylazoxymethanol, lovastatin, papaverine, warfarin, β-aminopropionitrile, dinoseb, furosemide, doxylamine, pravastatin, and metoclopramide. By delineation of the molecular mechanisms of the substances we identify six categories of reasons for misclassifications. Some of these limitations might also affect other in vitro methods assessing embryotoxicity. Substances that fall into these categories need to be included in future validation sets and in validation guidelines for embryotoxicity testing. Most importantly, we suggest conceivable improvements and additions to the EST which will resolve most of the limitations.

  11. Conversion efficiency limits and bandgap designs for multi-junction solar cells with internal radiative efficiencies below unity. (United States)

    Zhu, Lin; Mochizuki, Toshimitsu; Yoshita, Masahiro; Chen, Shaoqiang; Kim, Changsu; Akiyama, Hidefumi; Kanemitsu, Yoshihiko


    We calculated the conversion-efficiency limit ηsc and the optimized subcell bandgap energies of 1 to 5 junction solar cells without and with intermediate reflectors under 1-sun AM1.5G and 1000-sun AM1.5D irradiations, particularly including the impact of internal radiative efficiency (ηint) below unity for realistic subcell materials on the basis of an extended detailed-balance theory. We found that the conversion-efficiency limit ηsc significantly drops when the geometric mean ηint* of all subcell ηint in the stack reduces from 1 to 0.1, and that ηsc degrades linearly to logηint* for ηint* below 0.1. For ηint*<0.1 differences in ηsc due to additional intermediate reflectors became very small if all subcells are optically thick for sun light. We obtained characteristic optimized bandgap energies, which reflect both ηint* decrease and AM1.5 spectral gaps. These results provide realistic efficiency targets and design principles.

  12. Adaptive interference-aware multichannel assignment for shared overloaded small-cell access points under limited feedback

    KAUST Repository

    Radaydeh, Redha Mahmoud


    This paper proposes a reduced-complexity multichannel assignment scheme for short-range cellular systems. It treats the scenario when a number of small-cell (e.g., femtocell) access points (APs) can be shared to serve active scheduled users. The APs employ isotropic antenna arrays and operate using an open-access control strategy. To improve the reuse ratio of physical resources, the APs are assumed to occupy a single physical channel, wherein coordination among them is infeasible. On the other hand, to improve the spatial coverage, a scheduled user can be served by a single transmit channel from an AP at a time. For the case of overloaded APs and when the feedback links are capacity limited, the scheme attempts to identify the suitable transmit channels from the deployed APs in an adaptive manner such that certain performance and/or processing load limits are satisfied. The effects of some system and design parameters on the outcomes of the scheme are thoroughly discussed. Novel results for the statistics of the resulting interference power are presented, from which results for some performance measures and processing loads are obtained. Numerical and simulations results are provided to clarify the achieved gains, as compared with related models under different operating conditions. © 2013 IEEE.

  13. Limitation of immune tolerance-inducing thymic epithelial cell development by Spi-B-mediated negative feedback regulation. (United States)

    Akiyama, Nobuko; Shinzawa, Miho; Miyauchi, Maki; Yanai, Hiromi; Tateishi, Ryosuke; Shimo, Yusuke; Ohshima, Daisuke; Matsuo, Koichi; Sasaki, Izumi; Hoshino, Katsuaki; Wu, Guoying; Yagi, Shintaro; Inoue, Jun-ichiro; Kaisho, Tsuneyasu; Akiyama, Taishin


    Medullary thymic epithelial cells (mTECs) expressing the autoimmune regulator AIRE and various tissue-specific antigens (TSAs) are critical for preventing the onset of autoimmunity and may attenuate tumor immunity. However, molecular mechanisms controlling mTEC development remain elusive. Here, we describe the roles of the transcription factor Spi-B in mTEC development. Spi-B is rapidly up-regulated by receptor activator of NF-κB ligand (RANKL) cytokine signaling, which triggers mTEC differentiation, and in turn up-regulates CD80, CD86, some TSAs, and the natural inhibitor of RANKL signaling, osteoprotegerin (OPG). Spi-B-mediated OPG expression limits mTEC development in neonates but not in embryos, suggesting developmental stage-specific negative feedback regulation. OPG-mediated negative regulation attenuates cellularity of thymic regulatory T cells and tumor development in vivo. Hence, these data suggest that this negative RANKL-Spi-B-OPG feedback mechanism finely tunes mTEC development and function and may optimize the trade-off between prevention of autoimmunity and induction of antitumor immunity.

  14. A p53-dependent response limits epidermal stem cell functionality and organismal size in mice with short telomeres.

    Directory of Open Access Journals (Sweden)

    Ignacio Flores

    Full Text Available Telomere maintenance is essential to ensure proper size and function of organs with a high turnover. In particular, a dwarf phenotype as well as phenotypes associated to premature loss of tissue regeneration, including the skin (hair loss, hair graying, decreased wound healing, are found in mice deficient for telomerase, the enzyme responsible for maintaining telomere length. Coincidental with the appearance of these phenotypes, p53 is found activated in several tissues from these mice, where is thought to trigger cellular senescence and/or apoptotic responses. Here, we show that p53 abrogation rescues both the small size phenotype and restitutes the functionality of epidermal stem cells (ESC of telomerase-deficient mice with dysfunctional telomeres. In particular, p53 ablation restores hair growth, skin renewal and wound healing responses upon mitogenic induction, as well as rescues ESCmobilization defects in vivo and defective ESC clonogenic activity in vitro. This recovery of ESC functions is accompanied by a downregulation of senescence markers and an increased proliferation in the skin and kidney of telomerase-deficient mice with critically short telomeres without changes in apoptosis rates. Together, these findings indicate the existence of a p53-dependent senescence response acting on stem/progenitor cells with dysfunctional telomeres that is actively limiting their contribution to tissue regeneration, thereby impinging on tissue fitness.

  15. Disease-specific survival for limited-stage small-cell lung cancer affected by statistical method of assessment

    Directory of Open Access Journals (Sweden)

    Yuan Fei


    Full Text Available Abstract Background In general, prognosis and impact of prognostic/predictive factors are assessed with Kaplan-Meier plots and/or the Cox proportional hazard model. There might be substantive differences from the results using these models for the same patients, if different statistical methods were used, for example, Boag log-normal (cure-rate model, or log-normal survival analysis. Methods Cohort of 244 limited-stage small-cell lung cancer patients, were accrued between 1981 and 1998, and followed to the end of 2005. The endpoint was death with or from lung cancer, for disease-specific survival (DSS. DSS at 1-, 3- and 5-years, with 95% confidence limits, are reported for all patients using the Boag, Kaplan-Meier, Cox, and log-normal survival analysis methods. Factors with significant effects on DSS were identified with step-wise forward multivariate Cox and log-normal survival analyses. Then, DSS was ascertained for patients with specific characteristics defined by these factors. Results The median follow-up of those alive was 9.5 years. The lack of events after 1966 days precluded comparison after 5 years. DSS assessed by the four methods in the full cohort differed by 0–2% at 1 year, 0–12% at 3 years, and 0–1% at 5 years. Log-normal survival analysis indicated DSS of 38% at 3 years, 10–12% higher than with other methods; univariate 95% confidence limits were non-overlapping. Surgical resection, hemoglobin level, lymph node involvement, and superior vena cava (SVC obstruction significantly impacted DSS. DSS assessed by the Cox and log-normal survival analysis methods for four clinical risk groups differed by 1–6% at 1 year, 15–26% at 3 years, and 0–12% at 5 years; multivariate 95% confidence limits were overlapping in all instances. Conclusion Surgical resection, hemoglobin level, lymph node involvement, and superior vena cava (SVC obstruction all significantly impacted DSS. Apparent DSS for patients was influenced by the

  16. Mast cell proteases as pharmacological targets. (United States)

    Caughey, George H


    Mast cells are rich in proteases, which are the major proteins of intracellular granules and are released with histamine and heparin by activated cells. Most of these proteases are active in the granule as well as outside of the mast cell when secreted, and can cleave targets near degranulating mast cells and in adjoining tissue compartments. Some proteases released from mast cells reach the bloodstream and may have far-reaching actions. In terms of relative amounts, the major mast cell proteases include the tryptases, chymases, cathepsin G, carboxypeptidase A3, dipeptidylpeptidase I/cathepsin C, and cathepsins L and S. Some mast cells also produce granzyme B, plasminogen activators, and matrix metalloproteinases. Tryptases and chymases are almost entirely mast cell-specific, whereas other proteases, such as cathepsins G, C, and L are expressed by a variety of inflammatory cells. Carboxypeptidase A3 expression is a property shared by basophils and mast cells. Other proteases, such as mastins, are largely basophil-specific, although human basophils are protease-deficient compared with their murine counterparts. The major classes of mast cell proteases have been targeted for development of therapeutic inhibitors. Also, a human β-tryptase has been proposed as a potential drug itself, to inactivate of snake venins. Diseases linked to mast cell proteases include allergic diseases, such as asthma, eczema, and anaphylaxis, but also include non-allergic diseases such as inflammatory bowel disease, autoimmune arthritis, atherosclerosis, aortic aneurysms, hypertension, myocardial infarction, heart failure, pulmonary hypertension and scarring diseases of lungs and other organs. In some cases, studies performed in mouse models suggest protective or homeostatic roles for specific proteases (or groups of proteases) in infections by bacteria, worms and other parasites, and even in allergic inflammation. At the same time, a clearer picture has emerged of differences in the

  17. A limited sampling schedule to estimate mycophenolic Acid area under the concentration-time curve in hematopoietic cell transplantation recipients. (United States)

    Li, Hong; Mager, Donald E; Bemer, Meagan J; Salinger, David H; Vicini, Paolo; Sandmaier, Brenda M; Nash, Richard; McCune, Jeannine S


    Mycophenolate mofetil (MMF) is a key component of postgrafting immunosuppression in hematopoietic cell transplant (HCT) recipients. The plasma area under the curve (AUC) of its active metabolite, mycophenolic acid (MPA), is associated with MMF efficacy and toxicity. This study developed a population pharmacokinetic model of MPA in HCT recipients and created limited sampling schedules (LSSs) to enable individualized pharmacotherapy. A retrospective evaluation of MPA concentration-time data following a 2-hour MMF intravenous (IV) infusion was conducted in 77 HCT recipients. The final model consisted of 1 and 2 compartments for MMF and MPA pharmacokinetics, respectively. The mean estimated values (coefficient of variation, %) for total systemic clearance, distributional clearance, and central and peripheral compartment volumes of MPA were 36.9 L/h (34.5%), 15.3 L/h (80.4%), 11.9 L (71.7%), and 182 L (127%), respectively. No covariates significantly explained variability among individuals. Optimal LSSs were derived using a simulation approach based on the scaled mean squared error. A 5-sample schedule of 2, 2.5, 3, 5, and 6 hours from the start of the infusion precisely estimated MPA AUC(0-12 h) for Q12-hour IV MMF. A comparable schedule (2, 2.5, 3, 4, and 6 hours) similarly estimated MPA AUC(0-8) (h) for Q8-hour dosing.

  18. Hyperosmosis and its combination with nutrient-limitation are novel environmental stressors for induction of triacylglycerol accumulation in cells of Chlorella kessleri. (United States)

    Hirai, Kazuho; Hayashi, Taihei; Hasegawa, Yuri; Sato, Atsushi; Tsuzuki, Mikio; Sato, Norihiro


    Triacylglycerols of oleaginous algae are promising for production of food oils and biodiesel fuel. Air-drying of cells induces triacylglycerol accumulation in a freshwater green alga, Chlorella kessleri, therefore, it seems that dehydration, i.e., intracellular hyperosmosis, and/or nutrient-limitation are key stressors. We explored this possibility in liquid-culturing C. kessleri cells. Strong hyperosmosis with 0.9 M sorbitol or 0.45 M NaCl for two days caused cells to increase the triacylglycerol content in total lipids from 1.5 to 48.5 and 75.3 mol%, respectively, on a fatty acid basis, whereas nutrient-limitation caused its accumulation to 41.4 mol%. Even weak hyperosmosis with 0.3 M sorbitol or 0.15 M NaCl, when nutrient-limitation was simultaneously imposed, induced triacylglycerol accumulation to 61.9 and 65.7 mol%, respectively. Furthermore, culturing in three-fold diluted seawater, the chemical composition of which resembled that of the medium for the combinatory stress, enabled the cells to accumulate triacylglycerol up to 24.7 weight% of dry cells in only three days. Consequently, it was found that hyperosmosis is a novel stressor for triacylglycerol accumulation, and that weak hyperosmosis, together with nutrient-limitation, exerts a strong stimulating effect on triacylglycerol accumulation. A similar combinatory stress would contribute to the triacylglycerol accumulation in air-dried C. kessleri cells.

  19. Affinity cytochemistry analysis of mast cells in skin lesions: a possible tool to assess the timing of lesions after death. (United States)

    Bonelli, A; Bacci, S; Norelli, G A


    The histamine content in vital wounds is known to increase, with a zenith after 3 h, and then decrease until 24 h after wounding. We addressed whether this biochemical alteration has a morphological counterpart. Since the main source of skin histamine are mast cells, the distribution and number of these cells was assessed upon labeling with fluorescent avidin and with antibodies to the mast cell specific enzymes, chymase and tryptase. Analyses were performed on skin from 15 healthy controls (from surgical biopsies), from 15 post-mortem lesions and 75 vital lesions, obtained at autopsy from subjects who had survived from a few seconds to 24 h. The number of mast cells per unit area of section surface increased progressively with survival time, up to a maximum in subjects who survived 1-3 h ( pdeath ( paffinity cytochemistry can help to discriminate vital from post-mortem lesions and to estimate survival time after lesions.

  20. Matrix density alters zyxin phosphorylation, which limits peripheral process formation and extension in endothelial cells invading 3D collagen matrices. (United States)

    Abbey, Colette A; Bayless, Kayla J


    This study was designed to determine the optimal conditions required for known pro-angiogenic stimuli to elicit successful endothelial sprouting responses. We used an established, quantifiable model of endothelial cell (EC) sprout initiation where ECs were tested for invasion in low (1 mg/mL) and high density (5 mg/mL) 3D collagen matrices. Sphingosine 1-phosphate (S1P) alone, or S1P combined with stromal derived factor-1α (SDF) and phorbol ester (TPA), elicited robust sprouting responses. The ability of these factors to stimulate sprouting was more effective in higher density collagen matrices. S1P stimulation resulted in a significant increase in invasion distance, and with the exception of treatment groups containing phorbol ester, invasion distance was longer in 1mg/mL compared to 5mg/mL collagen matrices. Closer examination of cell morphology revealed that increasing matrix density and supplementing with SDF and TPA enhanced the formation of multicellular structures more closely resembling capillaries. TPA enhanced the frequency and size of lumen formation and correlated with a robust increase in phosphorylation of p42/p44 Erk kinase, while S1P and SDF did not. Also, a higher number of significantly longer extended processes formed in 5mg/mL compared to 1mg/mL collagen matrices. Because collagen matrices at higher density have been reported to be stiffer, we tested for changes in the mechanosensitive protein, zyxin. Interestingly, zyxin phosphorylation levels inversely correlated with matrix density, while levels of total zyxin did not change significantly. Immunofluorescence and localization studies revealed that total zyxin was distributed evenly throughout invading structures, while phosphorylated zyxin was slightly more intense in extended peripheral processes. Silencing zyxin expression increased extended process length and number of processes, while increasing zyxin levels decreased extended process length. Altogether these data indicate that ECs

  1. Cell surface hydrophobicity of oral Candida dubliniensis isolates following limited exposure to sub-therapeutic concentrations of chlorhexidine gluconate. (United States)

    Ellepola, Arjuna N B; Joseph, Bobby K; Khan, Z U


    Candidal adhesion has been implicated as the initial step in the pathogenesis of oral candidiasis and cell surface hydrophobicity (CSH) has been implicated in adhesion to mucosal surfaces. Candida dubliniensis is an opportunistic pathogen associated with recurrent oral candidiasis. Chlorhexidine gluconate is by far the commonest antiseptic mouth wash prescribed in dentistry. At dosage intervals the intraoral concentration of this antiseptic fluctuates considerably and reaches sub-therapeutic levels due to the dynamics of the oral cavity. Hence, the organisms undergo only a limited exposure to the antiseptic during treatment. The impact of this antiseptic following such exposure on CSH of C. dubliniensis isolates has not been investigated. Hence, the main objective of this study was to investigate the effect of brief exposure to sub-therapeutic concentrations of chlorhexidine gluconate on the CSH of C. dubliniensis isolates. Twelve oral isolates of C. dubliniensis were briefly exposed to three sub-therapeutic concentrations of 0.005%, 0.0025% and 0.00125% chlorhexidine gluconate for 30 min. Following subsequent removal of the drug, the CSH of the isolates was determined by a biphasic aqueous-hydrocarbon assay. Compared with the controls, exposure to 0.005% and 0.0025% chlorhexidine gluconate suppressed the relative CSH of the total sample tested by 44.49% (P 0.05), four isolates of the group were significantly affected. These findings imply that exposure to sub-therapeutic concentrations of chlorhexidine gluconate may suppress CSH of C. dublinienis isolates, thereby reducing its pathogenicity and highlights further the pharmacodynamics of chlorhexidine gluconate.

  2. Assessment of the impact of adherence and other predictors during HAART on various CD4 cell responses in resource-limited settings

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    Abrogoua DP


    Full Text Available Danho Pascal Abrogoua1,2, Brou Jerome Kablan1, Boua Alexis Thierry Kamenan1,3, Gilles Aulagner4, Konan N'Guessan1, Christian Zohoré11Laboratoire de Pharmacie Clinique, Pharmacologie et Therapeutique – UFR Sciences Pharmaceutiques et Biologiques, 2Laboratoire de Pharmacologie Clinique, CHU de Cocody, 3Service de Pharmacie, CHU de Cocody, Abidjan, Cote d'Ivoire, 4Service Pharmaceutique Hopital Louis Pradel, Lyon, FranceObjective: The aim of this study was to quantify, by modeling, the impact of significant predictors on CD4 cell response during antiretroviral therapy in a resource-limited setting.Methods: Modeling was used to determine which antiretroviral therapy response predictors (baseline CD4 cell count, clinical state, age, and adherence significantly influence immunological response in terms of CD4 cell gain compared to a reference value at different periods of monitoring.Results: At 6 months, CD4 cell response was significantly influenced by baseline CD4 count alone. The probability of no increase in CD4 cells was 2.6 higher in patients with a baseline CD4 cell count of ≥200/mm3. At 12 months, CD4 cell response was significantly influenced by both baseline CD4 cell count and adherence. The probability of no increase in CD4 cells was three times higher in patients with a baseline CD4 cell count of ≥200/mm3 and 0.15 times lower with adherent patients. At 18 months, CD4 cell response was also significantly influenced by both baseline CD4 cell count and adherence. The probability of no increase in CD4 cells was 5.1 times higher in patients with a baseline CD4 cell count of ≥200/mm3 and 0.28 times lower with adherent patients. At 24 months, optimal CD4 cell response was significantly influenced by adherence alone. Adherence increased the probability (by 5.8 of an optimal increase in CD4 cells. Age and baseline clinical state had no significant influence on immunological response.Conclusion: The relationship between adherence and CD4

  3. Puma and p21 represent cooperating checkpoints limiting self-renewal and chromosomal instability of somatic stem cells in response to telomere dysfunction. (United States)

    Sperka, Tobias; Song, Zhangfa; Morita, Yohei; Nalapareddy, Kodandaramireddy; Guachalla, Luis Miguel; Lechel, André; Begus-Nahrmann, Yvonne; Burkhalter, Martin D; Mach, Monika; Schlaudraff, Falk; Liss, Birgit; Ju, Zhenyu; Speicher, Michael R; Rudolph, K Lenhard


    The tumour suppressor p53 activates Puma-dependent apoptosis and p21-dependent cell-cycle arrest in response to DNA damage. Deletion of p21 improved stem-cell function and organ maintenance in progeroid mice with dysfunctional telomeres, but the function of Puma has not been investigated in this context. Here we show that deletion of Puma improves stem- and progenitor-cell function, organ maintenance and lifespan of telomere-dysfunctional mice. Puma deletion impairs the clearance of stem and progenitor cells that have accumulated DNA damage as a consequence of critically short telomeres. However, further accumulation of DNA damage in these rescued progenitor cells leads to increasing activation of p21. RNA interference experiments show that upregulation of p21 limits proliferation and evolution of chromosomal imbalances of Puma-deficient stem and progenitor cells with dysfunctional telomeres. These results provide experimental evidence that p53-dependent apoptosis and cell-cycle arrest act in cooperating checkpoints limiting tissue maintenance and evolution of chromosomal instability at stem- and progenitor-cell levels in response to telomere dysfunction. Selective inhibition of Puma-dependent apoptosis can result in temporary improvements in maintenance of telomere-dysfunctional organs.

  4. Mast cells are key mediators of cathelicidin-initiated skin inflammation in rosacea. (United States)

    Muto, Yumiko; Wang, Zhenping; Vanderberghe, Matthieu; Two, Aimee; Gallo, Richard L; Di Nardo, Anna


    Rosacea is a chronic inflammatory skin disease whose pathophysiological mechanism is still unclear. However, it is known that mast cell (MC) numbers are increased in the dermis of rosacea patients. MC proteases not only recruit other immune cells, which amplify the inflammatory response, but also cause vasodilation and angiogenesis. MCs are also one of the primary sources of cathelicidin LL-37 (Cath LL-37), an antimicrobial peptide that has been shown to be an enabler of rosacea pathogenesis. Here, we demonstrate that MCs are key mediators of cathelicidin-initiated skin inflammation. After Cath LL-37 injection into the dermis, MC-deficient B6.Cg-Kit(W-sh)/HNihrJaeBsmJ (KitW-sh) mice did not develop rosacea-like features. Conversely, chymase (Prosacea subjects who showed a decrease in matrix metalloproteinase activity (Prosacea treatment.

  5. A Numerically Subdominant CD8 T Cell Response to Matrix Protein of Respiratory Syncytial Virus Controls Infection with Limited Immunopathology.

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    Jie Liu


    Full Text Available CD8 T cells are involved in pathogen clearance and infection-induced pathology in respiratory syncytial virus (RSV infection. Studying bulk responses masks the contribution of individual CD8 T cell subsets to protective immunity and immunopathology. In particular, the roles of subdominant responses that are potentially beneficial to the host are rarely appreciated when the focus is on magnitude instead of quality of response. Here, by evaluating CD8 T cell responses in CB6F1 hybrid mice, in which multiple epitopes are recognized, we found that a numerically subdominant CD8 T cell response against DbM187 epitope of the virus matrix protein expressed high avidity TCR and enhanced signaling pathways associated with CD8 T cell effector functions. Each DbM187 T effector cell lysed more infected targets on a per cell basis than the numerically dominant KdM282 T cells, and controlled virus replication more efficiently with less pulmonary inflammation and illness than the previously well-characterized KdM282 T cell response. Our data suggest that the clinical outcome of viral infections is determined by the integrated functional properties of a variety of responding CD8 T cells, and that the highest magnitude response may not necessarily be the best in terms of benefit to the host. Understanding how to induce highly efficient and functional T cells would inform strategies for designing vaccines intended to provide T cell-mediated immunity.

  6. Phenotypical characterization, distribution and quantification of different mast cell subtypes in transmural biopsies from the gastrointestinal tract of cats with inflammatory bowel disease. (United States)

    Kleinschmidt, Sven; Harder, Jasmine; Nolte, Ingo; Marsilio, Sina; Hewicker-Trautwein, Marion


    In this study subtypes, distribution and number of mast cells were investigated within mucosa and submucosa of the gastrointestinal tract of 24 cats with inflammatory bowel disease (IBD) in comparison to 11 control cats. Paraffin sections of formalin-fixed transmural gastrointestinal biopsies from stomach, duodenum, jejunum, ileum and colon were examined. Mast cells were phenotyped and quantified based on their chymase and tryptase content, by applying a combined enzyme-histochemical and immunohistochemical double-labeling technique and on their heparin content by a metachromatic staining method (kresylecht-violet, MC(KEV)). Mast cells containing both chymase and tryptase were not found in any of the samples examined. Furthermore, in the stomach neither chymase (MC(C)) nor tryptase (MC(T)) bearing mast cells were detected. In cats with lymphocytic-plasmacytic enteritis or enterocolitis elevated numbers of MC(T) or MC(C) were identified in comparison to controls mainly located in the inflamed segments. The highest quantity of MC(C) was found in cats with eosinophilic gastroenterocolitis or enterocolitis in comparison to other IBD forms, but only minor numbers of MC(T) were detected in these cases. In cats with fibrosing enteropathy (FE) a decrease of MC(C) and mast cells containing heparin was detected in affected segments, while increased numbers of MC(T) were detected in all locations. The elevation in the number of MC(T) was higher in unaffected areas than in fibrotic regions. Regarding all IBD cases higher counts of MC(C) were found especially in the inflamed locations, whereas in unaffected segments increased numbers of MC(T) were detected. The clear predominance of MC(C) and MC(T) within the mucosa and of MC(KEV) within the submucosa of all cats examined possibly represents differences of the cytokine milieu within the intestinal layers. In FE, mast cells are possibly pivotal for the containment of the inflammatory process because of their antiinflammatory

  7. Optimal labeling dose, labeling time, and magnetic resonance imaging detection limits of ultrasmall superparamagnetic iron-oxide nanoparticle labeled mesenchymal stromal cells

    DEFF Research Database (Denmark)

    Mathiasen, Anders Bruun; Hansen, Louise; Friis, Tina;


    Background. Regenerative therapy is an emerging treatment modality. To determine migration and retention of implanted cells, it is crucial to develop noninvasive tracking methods. The aim was to determine ex vivo magnetic resonance imaging (MRI) detection limits of ultrasmall superparamagnetic iron...

  8. Temperature Dependence of Cell Division Timing Accounts for a Shift in the Thermal Limits of C. elegans and C. briggsae

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    Maria L. Begasse


    Full Text Available Cold-blooded animals, which cannot directly control their body temperatures, have adapted to function within specific temperature ranges that vary between species. However, little is known about what sets the limits of the viable temperature range. Here we show that the speed of the first cell division in C. elegans N2 varies with temperature according to the Arrhenius equation. However, it does so only within certain limits. Outside these limits we observe alterations in the cell cycle. Interestingly, these temperature limits also correspond to the animal’s fertile range. In C. briggsae AF16, isolated from a warmer climatic region, both the fertile range and the temperature range over which the speed of cell division follows the Arrhenius equation, are shifted toward higher temperatures. Our findings suggest that the viable range of an organism can be adapted in part to a different thermal range by adjusting the temperature tolerance of cell division.

  9. Western blot analysis of a limited number of cells: a valuable adjunct to proteome analysis of paraffin wax-embedded, alcohol-fixed tissue after laser capture microdissection. (United States)

    Martinet, Wim; Abbeloos, Vanessa; Van Acker, Nathalie; De Meyer, Guido R Y; Herman, Arnold G; Kockx, Mark M


    In recent years, laser capture microdissection (LCM) has been used successfully to obtain distinct populations of cells for subsequent molecular analysis. Because of the limited sample availability and the absence of in vitro amplification steps for proteins, the use of LCM for proteome analysis largely depends on highly sensitive protein detection methods. In this study, a western blot protocol was developed and validated for the detection of beta-actin and the moderately expressed cell death protein caspase-3 in small numbers of cells. Initially, cultured human U937 monocytes and whole sections of paraffin wax-embedded, alcohol-fixed human tonsils were used to optimize protein electrophoresis and western blotting conditions. High-performance NuPAGE Bis-Tris gels in combination with high-quality transfer membranes, optimized antibody concentrations, and a sensitive chemiluminescent substrate provided a strong signal for beta-actin with approximately 500 U937 cells. In the same way, procaspase-3 could be identified with approximately 1000 cells. Similar results were obtained with germinal centre cells that were procured from paraffin wax-embedded, alcohol-fixed human tonsils by LCM. Treatment of U937 cells with etoposide rapidly induced cell death and allowed the detection of active caspase-3 with approximately 2500 cells (0.8 pg of protein). The findings of this study suggest that western blotting is a valuable adjunct to proteome analysis of LCM procured cells.

  10. Efficient secretory expression of functional barley limit dextrinase inhibitor by high cell-density fermentation of Pichia pastoris

    DEFF Research Database (Denmark)

    Jensen, Johanne Mørch; Vester-Christensen, Malene Bech; Møller, Marie Sofie;


    The limit dextrinase inhibitor (LDI) from barley seeds acts specifically on limit dextrinase (LD), an endogenous starch debranching enzyme. LDI is a 14kDa hydrophobic protein containing four disulfide bonds and one unpaired thiol group previously found to be either glutathionylated or cysteinylat...

  11. Correlations Between the Density of Tryptase Positive Mast Cells (DMCT and that of New Blood Vessels (CD105+ in Patients with Gastric Cancer

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    Micu Gianina Viorica


    Full Text Available Mast cells proteases, tryptase and chymase are directly involved in the growth and progression of solid tumors due to their important role in tumor angiogenesis. We examined the density of tryptase positive mast cells and the mean density of new blood vessels in gastric malignant tumors of patients with and without Helicobacter pylori infection, using immunohistochemical staining for tryptase (for mast cells and CD 105 (for new vessels. Tryptase and CD 105 expression was detected in gastrectomy specimens. In this study, mast cell density correlates with angiogenesis and the growth and progression of gastric cancer. It also shows that the participation of Helicobacter pylori infection in the growth and progress of gastric neoplasia is due to an increase of peritumoral angiogenesis, with subsequent local and distant tumor spread and perivascular growth, but without perineural and nodal involvement.

  12. A meta-analysis of the Timing of Chest Radiotherapy in Patients with Limited-stage Small Cell Lung Cancer

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    Hui ZHAO


    Full Text Available Background and objective Although evidence for a significant survival benefit of chest radiotherapy has been proven, no conclusion could be drawn regarding the optimal timing of chest radiation. The aim of this study is to explore whether the timing of chest radiation may influence the survival of the patients with limited-stage small-cell lung cancer (LSSCLC by performing a literature-based meta-analysis. Methods By searching Medline, CENTRAL (the Cochrane central register of controlled trials, CBM, and CNKI, et al, we collected both domestic and overseas published documents about randomized trials comparing different timing chest radiotherapy in patients with LS-SCLC. Early chest radiation was regarded as beginning within 30 days after the start of chemotherapy. Random or fixed effect models were applied to conduct meta-analysis on the trials. The combined odds ratio (OR and the 95% confidence interval (CI were calculated to estimate the mortality in 2 or 3 years and toxicity of the two treatments. The statistical heterogeneity was determined by cochran’s Chi-square test (Q test. The Begg’ test was used to determine the publication bias. Results Six trials that included a total of 1 189 patients were analyzed in the meta-analysis 587 patients were in the early radiation group and 602 patients were in the late radiation group. Considering all 6 eligible trials, the overall survival at 2/3 years was not significantly different between early and late chest radiation (OR=0.78, 95%CI: 0.55-1.05, Z=1.68, P=0.093. For the toxicity, no obvious difference was observed for early chest radiotherapy compared with late irradiation in pneumonitis (OR=1.93, 95%CI: 0.97-3.86, P=0.797, esophagitis (OR=1.43, 95%CI: 0.95-2.13, P=0.572 and thrombocytopenia (OR=1.23, 95%CI: 0.88-1.77, P=0.746, respectively. Conclusion No statistical difference was observed in 2/3 years survival and toxicity, including pneumonitis, esophagitis and thrombocytopenia, between

  13. A Prospective Randomized Study of the Radiotherapy Volume for Limited-stage Small Cell Lung Cancer: A Preliminary Report

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    Xiao HU


    Full Text Available Background and objective Controversies exists with regard to target volumes as far as thoracic radiotherapy (TRT is concerned in the multimodality treatment for limited-stage small cell lung cancer (LSCLC. The aim of this study is to prospectively compare the local control rate, toxicity profiles, and overall survival (OS between patients received different target volumes irradiation after induction chemotherapy. Methods LSCLC patients received 2 cycles of etoposide and cisplatin (EP induction chemotherapy and were randomly assigned to receive TRT to either the post- or pre-chemotherapy tumor extent (GTV-T as study arm and control arm, CTV-N included the positive nodal drainage area for both arms. One to 2 weeks after induction chemotherapy, 45 Gy/30 Fx/19 d TRT was administered concurrently with the third cycle of EP regimen. After that, additional 3 cycles of EP consolidation were administered. Prophylactic cranial irradiation (PCI was administered to patients with a complete response. Results Thirty-seven and 40 patients were randomly assigned to study arm and control arm. The local recurrence rates were 32.4% and 28.2% respectively (P=0.80; the isolated nodal failure (INF rate were 3.0% and 2.6% respectively (P=0.91; all INF sites were in the ipsilateral supraclavicular fossa. Medastinal N3 disease was the risk factor for INF (P=0.02, OR=14.13, 95%CI: 1.47-136.13. During radiotherapy, grade I, II weight loss was observed in 29.4%, 5.9% and 56.4%, 7.7% patients respectively (P=0.04. Grade 0-I and II-III late pulmonary injury was developed in 97.1%, 2.9% and 86.4%, 15.4% patients respectively (P=0.07. Median survival time was 22.1 months and 26.9 months respectively. The 1 to 3-year OS were 77.9%, 44.4%, 37.3% and 75.8%, 56.3%, 41.7% respectively (P=0.79. Conclusion The preliminary results of this study indicate that irradiant the post-chemotherapy tumor extent (GTV-T and positive nodal drainage area did not decrease local control and overall

  14. Maraviroc intensification in patients with suppressed HIV viremia has limited effects on CD4+ T cell recovery and gene expression. (United States)

    Beliakova-Bethell, Nadejda; Jain, Sonia; Woelk, Christopher H; Witt, Mallory D; Sun, Xiaoying; Lada, Steven M; Spina, Celsa A; Goicoechea, Miguel; Rought, Steffney E; Haubrich, Richard; Dubé, Michael P


    Addition of the CCR5 inhibitor Maraviroc (MVC) to ongoing antiretroviral therapy increases CD4+ T cell counts in some virologically suppressed patients with suboptimal CD4+ T cell recovery. To understand the mechanisms by which MVC elicits increases in CD4+ T cell counts, the present study was undertaken to identify host factors (i.e. genes) that are modulated and are correlated with CD4+ T cell recovery during the 24weeks of MVC intensification in 32 subjects. Median changes of CD4+ T cell counts over 24weeks of MVC compared to baseline were 38cells/mm(3) (pMVC and 76cells/mm(3) per year during MVC intensification, however, this increase was not statistically significant (p=0.33). Microarray analysis (N=31,426 genes) identified a single differentially expressed gene, tumor necrosis factor alpha (TNF), which was modestly (1.44-fold, pMVC at week 24 compared to baseline. TNF differential expression was evaluated using an independent method of droplet digital PCR, but the difference was not significant (p=0.6). Changes in gene expression did not correlate with CD4+ T cell recovery or any changes in the CD4+ T cell maturation, proliferation and activation phenotypes. In summary, our data suggest that modest improvements of CD4+ T cell counts during MVC intensification cannot be explained by changes in gene expression elicited by MVC. However, the modest changes in T cell composition, including reduction of the percentages of Tregs, proliferating CD4+ T cells and senescent CD8+ T cells, suggest immunologically favorable effects of MVC.

  15. Improved flow cytometric method to enumerate residual cells: minimal linear detection limits for platelets, erythrocytes, and leukocytes. (United States)

    Pichler, J; Printz, D; Scharner, D; Trbojevic, D; Siekmann, J; Fritsch, G


    Increasing demand for quality control of blood products requires more sensitive methods to enumerate residual cells. Presently, the reported threshold (in cells per microliter) is 400 for red blood cells, 30-500 for platelets, and 1 for leukocytes. To examine precision and linearity in enumerating residual platelets and red blood cells, EDTA-anticoagulated blood from healthy donors was serially diluted with serum, stained in TruCount tubes using a no-lyse/no-wash procedure and a monoclonal antibody cocktail against the CD42a (FL1) and glycophorin-A (FL2) epitopes, and analyzed by flow cytometry. Leukocyte counts were determined in separate tubes. Cell preparation and analysis were performed once for 20 blood samples each and 20 times using the same specimen. Acquisition from the same tube was performed separately for platelets (threshold on FL1) and red blood cells (threshold on FL2). Multiparameter analysis was used for data evaluation. Linear results were obtained for platelets per microliter between 3,410 and 5 and for red blood cells per microliter between 54,000 and 3. For the lower cell concentrations, the coefficient of variation was 16.7% for platelets and 10.9% for red blood cells. The presented method allows the distinction between physiologically intact and ghost red blood cells. The method represents a reliable, sensitive, and accurate approach to quantify platelets and red blood cells in diluted blood. It can be applied to enumerate residual cells in plasma products and meets the increasing demand for quality control in blood components.

  16. B cell-derived transforming growth factor-β1 expression limits the induction phase of autoimmune neuroinflammation (United States)

    Bjarnadóttir, Kristbjörg; Benkhoucha, Mahdia; Merkler, Doron; Weber, Martin S.; Payne, Natalie L.; Bernard, Claude C. A.; Molnarfi, Nicolas; Lalive, Patrice H.


    Studies in experimental autoimmune encephalomyelitis (EAE), a murine model of multiple sclerosis (MS), have shown that regulatory B cells modulate the course of the disease via the production of suppressive cytokines. While data indicate a role for transforming growth factor (TGF)-β1 expression in regulatory B cell functions, this mechanism has not yet been tested in autoimmune neuroinflammation. Transgenic mice deficient for TGF-β1 expression in B cells (B–TGF-β1−/−) were tested in EAE induced by recombinant mouse myelin oligodendrocyte glycoprotein (rmMOG). In this model, B–TGF-β1−/− mice showed an earlier onset of neurologic impairment compared to their littermate controls. Exacerbated EAE susceptibility in B–TGF-β1−/− mice was associated with augmented CNS T helper (Th)1/17 responses. Moreover, selective B cell TGF-β1–deficiency increased the frequencies and activation of myeloid dendritic cells, potent professional antigen-presenting cells (APCs), suggesting that B cell-derived TGF-β1 can constrain Th1/17 responses through inhibition of APC activity. Collectively our data suggest that B cells can down-regulate the function of APCs, and in turn encephalitogenic Th1/17 responses, via TGF-β1, findings that may be relevant to B cell-targeted therapies. PMID:27708418

  17. A Stochastic Model of the Yeast Cell Cycle Reveals Roles for Feedback Regulation in Limiting Cellular Variability. (United States)

    Barik, Debashis; Ball, David A; Peccoud, Jean; Tyson, John J


    The cell division cycle of eukaryotes is governed by a complex network of cyclin-dependent protein kinases (CDKs) and auxiliary proteins that govern CDK activities. The control system must function reliably in the context of molecular noise that is inevitable in tiny yeast cells, because mistakes in sequencing cell cycle events are detrimental or fatal to the cell or its progeny. To assess the effects of noise on cell cycle progression requires not only extensive, quantitative, experimental measurements of cellular heterogeneity but also comprehensive, accurate, mathematical models of stochastic fluctuations in the CDK control system. In this paper we provide a stochastic model of the budding yeast cell cycle that accurately accounts for the variable phenotypes of wild-type cells and more than 20 mutant yeast strains simulated in different growth conditions. We specifically tested the role of feedback regulations mediated by G1- and SG2M-phase cyclins to minimize the noise in cell cycle progression. Details of the model are informed and tested by quantitative measurements (by fluorescence in situ hybridization) of the joint distributions of mRNA populations in yeast cells. We use the model to predict the phenotypes of ~30 mutant yeast strains that have not yet been characterized experimentally.

  18. Antigen-Experienced T cells Limit the Priming of Naïve T cells During Infection with Leishmania major1 (United States)

    Gray, Peter M.; Reiner, Steven L.; Smith, Deborah F.; Kaye, Paul M.; Scott, Phillip


    One mechanism to control immune responses following infection is to rapidly down regulate antigen presentation, which has been observed in acute viral and bacterial infections. Here we describe experiments designed to address whether antigen presentation is decreased after an initial response to Leishmania major. Naïve α-β-Leishmania-specific (ABLE) T cell receptor transgenic T cells were adoptively transferred into mice at various times after L. major infection to determine the duration of presentation of parasite-derived antigens. ABLE T cells responded vigorously at the initiation of infection, but the ability to prime these cells quickly diminished, independent of IL-10, regulatory T cells or antigen load. However, antigen-experienced clonal and polyclonal T cell populations could respond, indicating that the diminution in naïve ABLE cell responses was not due to lack of antigen presentation. Since naïve T cell priming could be restored by removal of the endogenous T cell population, or adoptive transfer of antigen pulsed dendritic cells, it appears that T cells that have previously encountered antigen during infection compete with naïve antigen-specific T cells. These results suggest that during L. major infection antigen-experienced T cells, rather than naïve T cells, may be primarily responsible for sustaining the immune response. PMID:16818747

  19. Endogenous activated protein C limits cancer cell extravasation through sphingosine-1-phosphate receptor 1-mediated vascular endothelial barrier enhancement

    NARCIS (Netherlands)

    G.L. van Sluis; T.M.H. Niers; C.T. Esmon; W. Tigchelaar; D.J. Richel; H.R. Buller; C.J.F. van Noorden; C.A. Spek


    Activated protein C (APC) has both anticoagulant activity and direct cell-signaling properties. APC has been reported to promote cancer cell migration/invasion and to inhibit apoptosis and therefore may exacerbate metastasis. Opposing these activities, APC signaling protects the vascular endothelial

  20. SF Treg cells transcribing high levels of Bcl-2 and microRNA-21 demonstrate limited apoptosis in RA

    NARCIS (Netherlands)

    van der Geest, Kornelis S. M.; Smigielska, Katarzyna; Park, Ji-Ah; Abdulahad, Wayel H.; Kim, Hye-Won; Kroesen, Bart-Jan; van den Berg, Anke; Boots, Annemieke M. H.; Lee, Eun-Bong; Brouwer, Elisabeth


    Objective. The aim of this study was to investigate the turnover of Treg cells in the SF of RA patients. Methods. Treg cells were enumerated in peripheral blood and SF of RA patients and analysed by flow cytometry for expression of the proliferation marker Ki-67 and binding of the apoptosis marker a

  1. Muscle-derived stem/progenitor cell dysfunction limits healthspan and lifespan in a murine progeria model (United States)

    Lavasani, Mitra; Robinson, Andria R.; Lu, Aiping; Song, Minjung; Feduska, Joseph M.; Ahani, Bahar; Tilstra, Jeremy S.; Feldman, Chelsea H.; Robbins, Paul D.; Niedernhofer, Laura J.; Huard, Johnny


    With ageing, there is a loss of adult stem cell function. However, there is no direct evidence that this has a causal role in ageing-related decline. We tested this using muscle-derived stem/progenitor cells (MDSPCs) in a murine progeria model. Here we show that MDSPCs from old and progeroid mice are defective in proliferation and multilineage differentiation. Intraperitoneal administration of MDSPCs, isolated from young wild-type mice, to progeroid mice confer significant lifespan and healthspan extension. The transplanted MDSPCs improve degenerative changes and vascularization in tissues where donor cells are not detected, suggesting that their therapeutic effect may be mediated by secreted factor(s). Indeed, young wild-type-MDSPCs rescue proliferation and differentiation defects of aged MDSPCs when co-cultured. These results establish that adult stem/progenitor cell dysfunction contributes to ageing-related degeneration and suggests a therapeutic potential of post-natal stem cells to extend health. PMID:22215083

  2. Pancreatic β-Cells Limit Autoimmune Diabetes via an Immunoregulatory Antimicrobial Peptide Expressed under the Influence of the Gut Microbiota. (United States)

    Sun, Jia; Furio, Laetitia; Mecheri, Ramine; van der Does, Anne M; Lundeberg, Erik; Saveanu, Loredana; Chen, Yongquan; van Endert, Peter; Agerberth, Birgitta; Diana, Julien


    Antimicrobial peptides (AMPs) expressed by epithelial and immune cells are largely described for the defense against invading microorganisms. Recently, their immunomodulatory functions have been highlighted in various contexts. However how AMPs expressed by non-immune cells might influence autoimmune responses in peripheral tissues, such as the pancreas, is unknown. Here, we found that insulin-secreting β-cells produced the cathelicidin related antimicrobial peptide (CRAMP) and that this production was defective in non-obese diabetic (NOD) mice. CRAMP administrated to prediabetic NOD mice induced regulatory immune cells in the pancreatic islets, dampening the incidence of autoimmune diabetes. Additional investigation revealed that the production of CRAMP by β-cells was controlled by short-chain fatty acids produced by the gut microbiota. Accordingly, gut microbiota manipulations in NOD mice modulated CRAMP production and inflammation in the pancreatic islets, revealing that the gut microbiota directly shape the pancreatic immune environment and autoimmune diabetes development.

  3. A MYC-Driven Change in Mitochondrial Dynamics Limits YAP/TAZ Function in Mammary Epithelial Cells and Breast Cancer. (United States)

    von Eyss, Björn; Jaenicke, Laura A; Kortlever, Roderik M; Royla, Nadine; Wiese, Katrin E; Letschert, Sebastian; McDuffus, Leigh-Anne; Sauer, Markus; Rosenwald, Andreas; Evan, Gerard I; Kempa, Stefan; Eilers, Martin


    In several developmental lineages, an increase in MYC expression drives the transition from quiescent stem cells to transit-amplifying cells. We show that MYC activates a stereotypic transcriptional program of genes involved in cell growth in mammary epithelial cells. This change in gene expression indirectly inhibits the YAP/TAZ co-activators, which maintain the clonogenic potential of these cells. We identify a phospholipase of the mitochondrial outer membrane, PLD6, as the mediator of MYC activity. MYC-dependent growth strains cellular energy resources and stimulates AMP-activated kinase (AMPK). PLD6 alters mitochondrial fusion and fission dynamics downstream of MYC. This change activates AMPK, which in turn inhibits YAP/TAZ. Mouse models and human pathological data show that MYC enhances AMPK and suppresses YAP/TAZ activity in mammary tumors.

  4. Modeling the cell-type dependence of diffusion-limited intracellular ice nucleation and growth during both vitrification and slow freezing (United States)

    Yang, Geer; Zhang, Aili; Xu, Lisa X.; He, Xiaoming


    In this study, a set of models for predicting the diffusion-limited ice nucleation and growth inside biological cells were established. Both the heterogeneous and homogeneous nucleation mechanisms were considered in the models. Molecular mobility including viscosity and mutual diffusion coefficient of aqueous cryoprotectant (i.e., glycerol here) solutions was estimated using models derived from the free volume theory for glass transition, which makes it possible to predict the two most important physical properties (i.e., viscosity and mutual diffusion coefficient) over wide ranges of temperature and concentration as encountered in cryopreservation. After being verified using experimental data, the models were used to predict the critical cooling rate (defined as the cooling rate required so that the crystallized volume is less than 0.1% of the cell volume) as a function of the initial glycerol concentration in a number of cell types with different sizes. For slowing freezing, it was found that the required critical cooling rate is cell-type dependent with influences from cell size and the ice nucleation and water transport parameters. In general, the critical cooling rate does not change significantly with the initial glycerol concentration used and tends to be higher for smaller cells. For vitrification, the required critical cooling rate does change significantly with the initial glycerol concentration used and tends to decrease with the decrease in cell size. However, the required critical cooling rate can be similar for cells with very different sizes. It was further found that the thermodynamic and kinetic parameters for intracellular ice formation associated with different cells rather than the cell size per se significantly affect the critical cooling rates required for vitrification. For all cell types, it was found that homogeneous nucleation dominates at ultrafast cooling rates and/or high glycerol concentrations, whereas heterogeneous nucleation becomes

  5. Interference Alignment-based Precoding and User Selection with Limited Feedback in Two-cell Downlink Multi-user MIMO Systems

    Directory of Open Access Journals (Sweden)

    Yin Zhu


    Full Text Available Interference alignment (IA is a new approach to address interference in modern multiple-input multiple-out (MIMO cellular networks in which interference is an important factor that limits the system throughput. System throughput in most IA implementation schemes is significantly improved only with perfect channel state information and in a high signal-to-noise ratio (SNR region. Designing a simple IA scheme for the system with limited feedback and investigating system performance at a low-to-medium SNR region is important and practical. This paper proposed a precoding and user selection scheme based on partial interference alignment in two-cell downlink multi-user MIMO systems under limited feedback. This scheme aligned inter-cell interference to a predefined direction by designing user’s receive antenna combining vectors. A modified singular value decomposition (SVD-based beamforming method and a corresponding user-selection algorithm were proposed for the system with low rate limited feedback to improve sum rate performance. Simulation results show that the proposed scheme achieves a higher sum rate than traditional schemes without IA. The modified SVD-based beamforming scheme is also superior to the traditional zero-forcing beamforming scheme in low-rate limited feedback systems. The proposed partial IA scheme does not need to collaborate between transmitters and joint design between the transmitter and the users. The scheme can be implemented with low feedback overhead in current MIMO cellular networks.

  6. Limited T-cell receptor diversity in liver-infiltrating lymphocytes from patients with primary biliary cirrhosis. (United States)

    Diu, A; Moebius, U; Ferradini, L; Genevée, C; Roman-Roman, S; Claudon, M; Delorme, D; Meuer, S; Hercend, T; Praz, F


    Primary biliary cirrhosis is associated with the presence of high-titer anti-mitochondrial autoantibodies as well as T-cell infiltration of the liver, suggesting the involvement of autoimmune mechanisms. We have studied here the sequences of T-cell receptor alpha and beta chains expressed by T-cell clones derived from liver-infiltrating lymphocytes of two patients with primary biliary cirrhosis. Among the eight clones studied from the first patient, four expressed the same member of the V beta 6 subfamily, associated with either V alpha 4 (three clones) or V alpha 21 (one clone) gene segment. Two other clones expressed an identical V beta 12 transcript, and two in-frame alpha chain transcripts, involving V alpha 2 and V alpha 7 gene segments. From the second patient, eight out of the nine clones were found to rearrange V beta 17-J beta 2.1 and V alpha 3 gene segments. The remaining clone expressed distinct T-cell receptor chains, involving V beta 9 and V alpha 11 gene segments. As deduced from the analysis of their junctional regions, the eight T-cell clones expressing V beta 17/V alpha 3 gene segments derived from only three different T cells. Furthermore, conserved amino acid motifs were found to be encoded in both the alpha and the beta-chain junctional regions. Together, these data show a local amplification of unique T lymphocytes in both patients. The use of identical V beta J beta and V alpha gene segments with similar junctional sequences by three different cells, evidenced in one of the two cases, strengthens the view that liver-infiltrating T lymphocytes are selected locally by autoantigens in PBC.

  7. Optimal Labeling Dose, Labeling Time, and Magnetic Resonance Imaging Detection Limits of Ultrasmall Superparamagnetic Iron-Oxide Nanoparticle Labeled Mesenchymal Stromal Cells

    Directory of Open Access Journals (Sweden)

    Anders Bruun Mathiasen


    Full Text Available Background. Regenerative therapy is an emerging treatment modality. To determine migration and retention of implanted cells, it is crucial to develop noninvasive tracking methods. The aim was to determine ex vivo magnetic resonance imaging (MRI detection limits of ultrasmall superparamagnetic iron-oxide (USPIO labeled mesenchymal stromal cells (MSCs. Materials and Methods. 248 gel-phantoms were constructed and scanned on a 1.5T MRI-scanner. Phantoms contained human MSCs preincubated with USPIO nanoparticles for 2, 6, or 21 hours using 5 or 10 μg USPIO/105 MSCs. In addition, porcine hearts were scanned after injection of USPIO labeled MSCs. Results. Using 21 h incubation time and 10 μg USPIO/105 MSCs, labeled cells were clearly separated from unlabeled cells on MRI using 250.000 (P<0.001, 500.000 (P=0.007, and 1.000.000 MSCs (P=0.008. At lower incubation times and doses, neither labeled nor unlabeled cells could be separated. In porcine hearts labeled, but not unlabeled, MSCs were identified on MRI. Conclusions. As few as 250.000 MSCs can be detected on MRI using 21 h incubation time and 10 μg USPIO/105 MSCs. At lower incubation times and doses, several million cells are needed for MRI detection. USPIO labeled cells can be visualized by MRI in porcine myocardial tissue.

  8. Yersinia pseudotuberculosis supports Th17 differentiation and limits de novo regulatory T cell induction by directly interfering with T cell receptor signaling. (United States)

    Pasztoi, Maria; Bonifacius, Agnes; Pezoldt, Joern; Kulkarni, Devesha; Niemz, Jana; Yang, Juhao; Teich, René; Hajek, Janina; Pisano, Fabio; Rohde, Manfred; Dersch, Petra; Huehn, Jochen


    Adaptive immunity critically contributes to control acute infection with enteropathogenic Yersinia pseudotuberculosis; however, the role of CD4(+) T cell subsets in establishing infection and allowing pathogen persistence remains elusive. Here, we assessed the modulatory capacity of Y. pseudotuberculosis on CD4(+) T cell differentiation. Using in vivo assays, we report that infection with Y. pseudotuberculosis resulted in enhanced priming of IL-17-producing T cells (Th17 cells), whereas induction of Foxp3(+) regulatory T cells (Tregs) was severely disrupted in gut-draining mesenteric lymph nodes (mLNs), in line with altered frequencies of tolerogenic and proinflammatory dendritic cell (DC) subsets within mLNs. Additionally, by using a DC-free in vitro system, we could demonstrate that Y. pseudotuberculosis can directly modulate T cell receptor (TCR) downstream signaling within naïve CD4(+) T cells and Tregs via injection of effector molecules through the type III secretion system, thereby affecting their functional properties. Importantly, modulation of naïve CD4(+) T cells by Y. pseudotuberculosis resulted in an enhanced Th17 differentiation and decreased induction of Foxp3(+) Tregs in vitro. These findings shed light to the adjustment of the Th17-Treg axis in response to acute Y. pseudotuberculosis infection and highlight the direct modulation of CD4(+) T cell subsets by altering their TCR downstream signaling.

  9. Reactive Oxygen Species Limit the Ability of Bone Marrow Stromal Cells to Support Hematopoietic Reconstitution in Aging Mice (United States)

    Khatri, Rahul; Krishnan, Shyam; Roy, Sushmita; Chattopadhyay, Saborni; Kumar, Vikash


    Aging of organ and abnormal tissue regeneration are recurrent problems in physiological and pathophysiological conditions. This is most crucial in case of high-turnover tissues, like bone marrow (BM). Using reciprocal transplantation experiments in mouse, we have shown that self-renewal potential of hematopoietic stem and progenitor cells (HSPCs) and BM cellularity are markedly influenced with the age of the recipient mice rather than donor mice. Moreover, accumulation of excessive reactive oxygen species (ROS) in BM stromal cells compared to HSPC compartment, in time-dependent manner, suggests that oxidative stress is involved in suppression of BM cellularity by affecting microenvironment in aged mice. Treatment of these mice with a polyphenolic antioxidant curcumin is found to partially quench ROS, thereby rescues stromal cells from oxidative stress-dependent cellular injury. This rejuvenation of stromal cells significantly improves hematopoietic reconstitution in 18-month-old mice compared to age control mice. In conclusion, this study implicates the role of ROS in perturbation of stromal cell function upon aging, which in turn affects BM's reconstitution ability in aged mice. Thus, a rejuvenation therapy using curcumin, before HSPC transplantation, is found to be an efficient strategy for successful marrow reconstitution in older mice. PMID:27140293

  10. Feasibility and Limits of Magnetically Labeling Primary Cultured Rat T Cells with Ferumoxides Coupled with Commonly Used Transfection Agents

    Directory of Open Access Journals (Sweden)

    Cedric Berger


    Full Text Available Visualization and quantification of inflammatory processes is of high importance for early diagnosis of a multitude of diseases. Magnetic resonance imaging (MRI using iron oxide (FeO nanoparticles as contrast agents allows the study of macrophage infiltration during inflammation in a variety of tissues. Macrophages are effectors of the immune response, their appearance being orchestrated by activated T lymphocytes. Therefore, tracking of labeled T lymphocytes, which initiate the immune process, should enable earlier detection of tissue inflammation. In this study, we investigate the feasibility of specifically labeling harvested T cells by using dextran-coated FeO nanoparticles and commonly available transfection agents (TAs. Physicochemical properties of the newly formed FeO/TA vesicles were determined as well as their cell toxicity and their T cell activation potential. The labeling efficiency of each FeO/TA combination was evaluated by measuring the transverse MRI relaxation rate R2 by X-ray spectroscopy and magnetic selection. Toxicity and labeling efficacy differed significantly among TAs. The best results were achieved by using polyamine TAs and in particular by using poly-l-lysine at a concentration of 1.5 µg/mL administered in combination with 22.5 µg iron/mL. By using this protocol, up to 60% of harvested T cells could be labeled. Microscopic investigation revealed FeO/TA nanoparticles not only localized within the cytoplasma of the cells but also sticking to the outer membrane surface.

  11. Transient inhibition of ROR-γt therapeutically limits intestinal inflammation by reducing TH17 cells and preserving ILC3 (United States)

    Withers, David R.; Hepworth, Matthew R.; Wang, Xinxin; Mackley, Emma C.; Halford, Emily E.; Dutton, Emma E.; Marriott, Clare L.; Brucklacher-Waldert, Verena; Veldhoen, Marc; Kelsen, Judith; Baldassano, Robert N.; Sonnenberg, Gregory F.


    RAR-related orphan receptor γt (ROR-γt) directs differentiation of pro-inflammatory T helper 17 (TH17) cells and is a potential therapeutic target in chronic autoimmune and inflammatory diseases1–3. However, ROR-γt-dependent group 3 innate lymphoid cells (ILC3s) provide essential immunity and tissue protection in the intestine4–11, suggesting that targeting ROR-γt could also result in impaired host defense to infection or enhanced tissue damage. Here, we demonstrate that transient chemical inhibition of ROR-γt in mice selectively reduces cytokine production from TH17 cells but not ILC3s in the context of intestinal infection with Citrobacter rodentium, resulting in preserved innate immunity. Transient genetic deletion of ROR-γt in mature ILC3s also did not impair cytokine responses in the steady state or during infection. Finally, pharmacologic inhibition of ROR-γt provided therapeutic benefit in mouse models of intestinal inflammation, and reduced the frequencies of TH17 cells but not ILC3s isolated from primary intestinal samples of individuals with inflammatory bowel disease (IBD). Collectively, these results reveal differential requirements for ROR-γt in the maintenance of TH17 cell versus ILC3 responses, and suggest that transient inhibition of ROR-γt is a safe and effective therapeutic approach during intestinal inflammation. PMID:26878233

  12. Role of eicosanoids and white blood cells in the beneficial effects of limited reperfusion after ischemia-reperfusion injury in skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, R.J.; Cambria, R.A.; Dikdan, G.; Lysz, T.W.; Hobson, R.W. II (UMDNJ-New Jersey Medical School, Newark (USA))


    Limiting the rate of reperfusion blood flow has been shown to be beneficial locally in models of ischemia-reperfusion injury. We investigated the effects of this on eicosanoids (thromboxane B2, 6-keto-PGF1 alpha, and leukotriene B4), white blood cell activation, and skeletal muscle injury as quantitated by triphenyltetrazolium chloride and technetium-99m pyrophosphate after ischemia-reperfusion injury in an isolated gracilis muscle model in 16 anesthetized dogs. One gracilis muscle in each dog was subjected to 6 hours of ischemia followed by 1 hour of limited reperfusion and then by a second hour of normal reperfusion. The other muscle was subjected to 6 hours of ischemia followed by 2 hours of normal reperfusion. Six dogs each were used as normal reperfusion controls (NR) and limited reperfusion controls (LR), with 5 dogs being treated with a thromboxane synthetase inhibitor (LR/TSI) and another five with a leukotriene inhibitor (LR/LI). LR in all three groups (LR, LR/TSI, and LR/LI) showed a benefit in skeletal muscle injury as measured by triphenyltetrazolim chloride and technetium-99m pyrophosphate when compared with NR. However, there was no significant difference between the groups with LR regarding eicosanoid levels and white blood cell activation when compared with NR. These results demonstrate that LR produces benefits by mechanisms other than those dependent upon thromboxane A2, prostacyclin, or white blood cell activation.

  13. Caspase-8 acts as a molecular rheostat to limit RIPK1- and MyD88-mediated dendritic cell activation. (United States)

    Cuda, Carla M; Misharin, Alexander V; Gierut, Angelica K; Saber, Rana; Haines, G Kenneth; Hutcheson, Jack; Hedrick, Stephen M; Mohan, Chandra; Budinger, G Scott; Stehlik, Christian; Perlman, Harris


    Caspase-8, an executioner enzyme in the death receptor pathway, was shown to initiate apoptosis and suppress necroptosis. In this study, we identify a novel, cell death-independent role for caspase-8 in dendritic cells (DCs): DC-specific expression of caspase-8 prevents the onset of systemic autoimmunity. Failure to express caspase-8 has no effect on the lifespan of DCs but instead leads to an enhanced intrinsic activation and, subsequently, more mature and autoreactive lymphocytes. Uncontrolled TLR activation in a RIPK1-dependent manner is responsible for the enhanced functionality of caspase-8-deficient DCs, because deletion of the TLR-signaling mediator, MyD88, ameliorates systemic autoimmunity induced by caspase-8 deficiency. Taken together, these data demonstrate that caspase-8 functions in a cell type-specific manner and acts uniquely in DCs to maintain tolerance.

  14. A Markov Chain Approach for Defining the Fundamental Efficiency Limits of Classical and Bifacial Multi-junction Tandem Solar Cells

    CERN Document Server

    Alam, Muhammad A


    Bifacial tandem cells promise to reduce three fundamental losses (above-bandgap, below bandgap, and the uncollected light between panels) inherent in classical single junction PV systems. The successive filtering of light through the bandgap cascade, and requirement of current continuity make optimization of tandem cells difficult, accessible only to numerical solution through computer modeling. The challenge is even more complicated for bifacial design. In this paper, we use an elegantly simple Markov chain approach to show that the essential physics of optimization is intuitively obvious, and deeply insightful results can obtained analytically with a few lines of algebra. This powerful approach reproduces, as special cases, all the known results of traditional/bifacial tandem cells, and highlights the asymptotic efficiency gain of these technologies.

  15. Evaluation and staging of squamous cell carcinoma of the oral cavity and oropharynx: limitations despite technological breakthroughs. (United States)

    Zafereo, Mark E


    Squamous cell carcinoma of the oral cavity (SCCOC) and squamous cell carcinoma of the oropharynx (SCCOP) represent two distinct disease entities. SCCOC continues to be related to tobacco risk factors, and the current anatomic staging system provides useful prognostic value. Most patients with SCCOP in Western countries now have HPV-associated tumors, and tumor HPV status is considered the most important prognostic factor. Smoking status is emerging as an important prognostic factor for HPV-driven SCCOP, independent of tumor HPV status. Sentinel lymph node biopsy and FDG-PET/CT imaging are diagnostic staging tools useful in select patients with SCCOC and SCCOP.

  16. Current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Loescher, D.H. [Sandia National Labs., Albuquerque, NM (United States). Systems Surety Assessment Dept.; Noren, K. [Univ. of Idaho, Moscow, ID (United States). Dept. of Electrical Engineering


    The current that flows between the electrical test equipment and the nuclear explosive must be limited to safe levels during electrical tests conducted on nuclear explosives at the DOE Pantex facility. The safest way to limit the current is to use batteries that can provide only acceptably low current into a short circuit; unfortunately this is not always possible. When it is not possible, current limiters, along with other design features, are used to limit the current. Three types of current limiters, the fuse blower, the resistor limiter, and the MOSFET-pass-transistor limiters, are used extensively in Pantex test equipment. Detailed failure mode and effects analyses were conducted on these limiters. Two other types of limiters were also analyzed. It was found that there is no best type of limiter that should be used in all applications. The fuse blower has advantages when many circuits must be monitored, a low insertion voltage drop is important, and size and weight must be kept low. However, this limiter has many failure modes that can lead to the loss of over current protection. The resistor limiter is simple and inexpensive, but is normally usable only on circuits for which the nominal current is less than a few tens of milliamperes. The MOSFET limiter can be used on high current circuits, but it has a number of single point failure modes that can lead to a loss of protective action. Because bad component placement or poor wire routing can defeat any limiter, placement and routing must be designed carefully and documented thoroughly.

  17. A limited role for p21(Cip1/Waf1) in maintaining normal hematopoietic stem cell functioning

    NARCIS (Netherlands)

    Van Os, Ronald; Kamminga, Leonie M.; Ausema, Albertina; Bystrykh, Leonid V.; Draijer, Deanna P.; Van Pelt, Kyrjon; Dontje, Bert; De Haan, Gerald


    Several studies have suggested that the cyclin-dependent kinase (CDK) inhibitor p21 plays a crucial role in regulating hematopoietic stem and progenitor pool size. To allow assessment of long-term stem cell functioning in vivo, we have backcrossed a p21 null allele to C57BL/6 (B6) mice, the most com

  18. Distinct evolution of TLR-mediated dendritic cell cytokine secretion in patients with limited and diffuse cutaneous systemic sclerosis.

    NARCIS (Netherlands)

    Bon, L. van; Popa, C.; Huibens, R.J.F.; Vonk, M.C.; York, M.; Simms, R.; Hesselstrand, R.; Wuttge, D.M.; Lafyatis, R.; Radstake, T.R.D.J.


    BACKGROUND: Systemic sclerosis (SSc) is an autoimmune disease and accumulating evidence suggests a role for Toll-like receptor (TLR)-mediated activation of dendritic cells (DCs). OBJECTIVE: To map TLR-mediated cytokine responses of DCs from patients with SSc. METHODS: 45 patients with SSc were inclu

  19. T cell-mediated cytotoxicity against p53-protein derived peptides in bulk and limiting dilution cultures of healthy donors

    DEFF Research Database (Denmark)

    Röpke, M; Regner, M; Claesson, M H


    -I restricted epitopes for T cell recognition and p53-derived peptides have been suggested as targets for tumour-specific cytotoxic T lymphocytes (CTL). Our primary aim was to estimate the frequencies of p53-peptide reactive CTL precursors (CTLp) in peripheral blood from healthy young individuals. We selected...

  20. A simple robust and accurate a posteriori sub-cell finite volume limiter for the discontinuous Galerkin method on unstructured meshes (United States)

    Dumbser, Michael; Loubère, Raphaël


    In this paper we propose a simple, robust and accurate nonlinear a posteriori stabilization of the Discontinuous Galerkin (DG) finite element method for the solution of nonlinear hyperbolic PDE systems on unstructured triangular and tetrahedral meshes in two and three space dimensions. This novel a posteriori limiter, which has been recently proposed for the simple Cartesian grid case in [62], is able to resolve discontinuities at a sub-grid scale and is substantially extended here to general unstructured simplex meshes in 2D and 3D. It can be summarized as follows: At the beginning of each time step, an approximation of the local minimum and maximum of the discrete solution is computed for each cell, taking into account also the vertex neighbors of an element. Then, an unlimited discontinuous Galerkin scheme of approximation degree N is run for one time step to produce a so-called candidate solution. Subsequently, an a posteriori detection step checks the unlimited candidate solution at time t n + 1 for positivity, absence of floating point errors and whether the discrete solution has remained within or at least very close to the bounds given by the local minimum and maximum computed in the first step. Elements that do not satisfy all the previously mentioned detection criteria are flagged as troubled cells. For these troubled cells, the candidate solution is discarded as inappropriate and consequently needs to be recomputed. Within these troubled cells the old discrete solution at the previous time tn is scattered onto small sub-cells (Ns = 2 N + 1 sub-cells per element edge), in order to obtain a set of sub-cell averages at time tn. Then, a more robust second order TVD finite volume scheme is applied to update the sub-cell averages within the troubled DG cells from time tn to time t n + 1. The new sub-grid data at time t n + 1 are finally gathered back into a valid cell-centered DG polynomial of degree N by using a classical conservative and higher order

  1. Phosphorus limitation and starvation effects on cell growth and lipid accumulation in Isochrysis galbana U4 for biodiesel production. (United States)

    Roopnarain, A; Gray, V M; Sym, S D


    The effect of varying levels of phosphorus (P) on Isochrysis galbana U4 growth, pigmentation and lipid accumulation were investigated. A reduction in the P content to 25% of the recommended level for f/2 medium did not lead to declines in cell growth rates or lipid accumulation levels relative to the cultures maintained on medium supplemented with the normal P dose. Evidence suggesting that the recommended P supply in f/2 exceeds the requirements for maximal algal growth has obvious economic implications for the mass production of I. galbana for biodiesel production. When P supply was in excess this species was also found to accumulate intracellular levels of P that exceeded by up to 6 times its P requirements for growth and cell division. The reduction in P concentration to levels below 25% resulted in P starvation stimulated chlorophyll reductions and carotenoid and lipid accumulation in this species.

  2. Regulation of glutamate dehydrogenase activity in relation to carbon limitation and protein catabolism in carrot cell suspension cultures. (United States)

    Robinson, S A; Stewart, G R; Phillips, R


    Glutamate dehydrogenase (GDH) specific activity and function have been studied in cell suspension cultures of carrot (Daucus carota L. cv Chantenay) in response to carbon and nitrogen supply in the culture medium. The specific activity of GDH was derepressed in sucrose-starved cells concomitant with protein catabolism, ammonium excretion, and the accumulation of metabolically active amino acids. The addition of sucrose led to a rapid decrease in GDH specific activity, an uptake of ammonium from the medium, and a decrease in amino acid levels. The extent of GDH derepression was correlated positively with cellular glutamate concentration. These findings strengthen the view that the function of GDH is the catabolism of glutamate, which under conditions of carbon stress provides carbon skeletons for tricarboxylic acid cycle activity.

  3. A reduced population of CD103(+)CD11b(+) dendritic cells has a limited impact on oral Salmonella infection. (United States)

    Fernández-Santoscoy, María; Wenzel, Ulf Alexander; Persson, Emma; Yrlid, Ulf; Agace, William; Wick, Mary Jo


    CD103(+)CD11b(+) dendritic cells (DC) are the major migratory DC subset in the small intestine lamina propria (siLP) and their survival is dependent on the transcription factor interferon regulatory factor 4 (IRF4). Mice with a DC-specific deletion of irf4 (CD11c-cre.Irf4 mice) have reduced mucosal CD103(+)CD11b(+) DC and altered T cell differentiation to protein antigen. The influence of CD103(+)CD11b(+) DC on oral infection with the gastrointestinal pathogen Salmonella, however, is poorly understood and is investigated here. We show that, despite being infected with Salmonella, CD11c-cre.Irf4 mice (called Cre(+) mice) conserve the reduction in CD103(+)CD11b(+) DC observed in naive Cre(+) mice, particularly in the mesenteric lymph nodes (MLN) but also in the siLP at day 3 post infection. Moreover, Salmonella-infected Cre(+) mice have a similar bacterial burden in intestinal tissues (siLP, MLN and Peyer's patches) as well as the spleen compared to infected Cre(-) controls. The T cell compartment, including the frequency of IFN-γ and IL-17-producing T cells, is not altered in intestinal tissues of Salmonella-infected Cre(+) mice relative to infected Cre(-) controls. In addition, no difference between infected Cre(+) and Cre(-) mice was observed in either the concentration of IL-6 or IL-17 in whole tissue lysates of siLP, MLN or Peyer's patches or in the serum concentration of Salmonella-specific IgG and IgM. Overall the data suggest that the reduction of CD103(+)CD11b(+) DC in Cre(+) mice has little if any impact on Salmonella burden in infected tissues or eliciting effector functions important in host survival at later stages of the infection.

  4. Graft vascularization is a critical rate-limiting step in skeletal stem cell-mediated posterolateral spinal fusion. (United States)

    Giannicola, Giuseppe; Ferrari, Emiliano; Citro, Gennaro; Sacchetti, Benedetto; Corsi, Alessandro; Riminucci, Mara; Cinotti, Gianluca; Bianco, Paolo


    The ability of skeletal stem cells (SSCs) to direct spinal fusion (SF) upon transplantation in conjunction with osteoconductive biomaterials was investigated in a rabbit model. When tested in a mouse heterotopic transplantation assay, rabbit SSCs and Pro-Osteon 500R was osteoconductive and supported osteogenesis. When used in a SF model, the same constructs induced bone formation in periapophyseal regions (PARs). In this respect, they proved to be superior to grafts of cell-free carrier or total uncultured bone marrow-carrier constructs, used as controls. However, interapophyseal regions (IARs) remained devoid of new bone, such that true bony bridging of adjacent transverse apophyses (true SF) could not be achieved. Interestingly, this could not be predicted from high-resolution radiography. A systematic histological survey of the entire graft harvested at 6 months was essential for proper assessment of the transplantation procedure outcome. Immunohistochemical analysis of microvessel density revealed that IARs remained undervascularized, as compared to PARs, suggesting that differential vascularization could account for the absence or presence of new bone formation in the same regions. SF is an extreme model of stem cell-directed bone regeneration, requiring a combination of orthotopic (PAR) and heterotopic (IAR) bone formation. Our data show that, in this setting, graft size can be critical with respect to the necessary neovascularization, a crucial variable independent of proper osteogenic and osteoconductive competence of the cells and materials employed. Furthermore, stringent histological studies are mandatory for proper assessment of outcomes in SF studies, in which the use of mineralized materials can make radiographic assessment misleading.

  5. The potent Cdc7-Dbf4 (DDK kinase inhibitor XL413 has limited activity in many cancer cell lines and discovery of potential new DDK inhibitor scaffolds.

    Directory of Open Access Journals (Sweden)

    Nanda Kumar Sasi

    Full Text Available Cdc7-Dbf4 kinase or DDK (Dbf4-dependent kinase is required to initiate DNA replication by phosphorylating and activating the replicative Mcm2-7 DNA helicase. DDK is overexpressed in many tumor cells and is an emerging chemotherapeutic target since DDK inhibition causes apoptosis of diverse cancer cell types but not of normal cells. PHA-767491 and XL413 are among a number of potent DDK inhibitors with low nanomolar IC50 values against the purified kinase. Although XL413 is highly selective for DDK, its activity has not been extensively characterized on cell lines. We measured anti-proliferative and apoptotic effects of XL413 on a panel of tumor cell lines compared to PHA-767491, whose activity is well characterized. Both compounds were effective biochemical DDK inhibitors but surprisingly, their activities in cell lines were highly divergent. Unlike PHA-767491, XL413 had significant anti-proliferative activity against only one of the ten cell lines tested. Since XL413 did not effectively inhibit DDK in multiple cell lines, this compound likely has limited bioavailability. To identify potential leads for additional DDK inhibitors, we also tested the cross-reactivity of ∼400 known kinase inhibitors against DDK using a DDK thermal stability shift assay (TSA. We identified 11 compounds that significantly stabilized DDK. Several inhibited DDK with comparable potency to PHA-767491, including Chk1 and PKR kinase inhibitors, but had divergent chemical scaffolds from known DDK inhibitors. Taken together, these data show that several well-known kinase inhibitors cross-react with DDK and also highlight the opportunity to design additional specific, biologically active DDK inhibitors for use as chemotherapeutic agents.

  6. The potent Cdc7-Dbf4 (DDK) kinase inhibitor XL413 has limited activity in many cancer cell lines and discovery of potential new DDK inhibitor scaffolds. (United States)

    Sasi, Nanda Kumar; Tiwari, Kanchan; Soon, Fen-Fen; Bonte, Dorine; Wang, Tong; Melcher, Karsten; Xu, H Eric; Weinreich, Michael


    Cdc7-Dbf4 kinase or DDK (Dbf4-dependent kinase) is required to initiate DNA replication by phosphorylating and activating the replicative Mcm2-7 DNA helicase. DDK is overexpressed in many tumor cells and is an emerging chemotherapeutic target since DDK inhibition causes apoptosis of diverse cancer cell types but not of normal cells. PHA-767491 and XL413 are among a number of potent DDK inhibitors with low nanomolar IC50 values against the purified kinase. Although XL413 is highly selective for DDK, its activity has not been extensively characterized on cell lines. We measured anti-proliferative and apoptotic effects of XL413 on a panel of tumor cell lines compared to PHA-767491, whose activity is well characterized. Both compounds were effective biochemical DDK inhibitors but surprisingly, their activities in cell lines were highly divergent. Unlike PHA-767491, XL413 had significant anti-proliferative activity against only one of the ten cell lines tested. Since XL413 did not effectively inhibit DDK in multiple cell lines, this compound likely has limited bioavailability. To identify potential leads for additional DDK inhibitors, we also tested the cross-reactivity of ∼400 known kinase inhibitors against DDK using a DDK thermal stability shift assay (TSA). We identified 11 compounds that significantly stabilized DDK. Several inhibited DDK with comparable potency to PHA-767491, including Chk1 and PKR kinase inhibitors, but had divergent chemical scaffolds from known DDK inhibitors. Taken together, these data show that several well-known kinase inhibitors cross-react with DDK and also highlight the opportunity to design additional specific, biologically active DDK inhibitors for use as chemotherapeutic agents.

  7. Limited Neutrality

    DEFF Research Database (Denmark)

    Nielsen, Morten Ebbe Juul


    Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."......Article Concerning the prospect of a kind of limited neutrality in place of the standard liberal egalitarian "neutrality of justification."...

  8. Limiting Skepticism

    DEFF Research Database (Denmark)

    Hendricks, Vincent Fella; Symons, John


    Skeptics argue that the acquisition of knowledge is impossible given the standing possibility of error. We present the limiting convergence strategy for responding to skepticism and discuss the relationship between conceivable error and an agent’s knowledge in the limit. We argue that the skeptic...

  9. Research data supporting “Towards Cellular Sieving: Exploring the Limits of Scaffold Accessibility for Cell-Type Specific Invasion”


    Ashworth, Jennifer C; Mehr, Marco; Buxton, Paul G.; Best, Serena M.; Cameron, Ruth E.


    Zip folder containing sample reconstructed Micro-CT scans (.tif files) from each scaffold condition. Image pixel size is 3.1 μm. Each image plane is perpendicular to the direction of cell invasion (i.e. parallel to the seeding plane). Two Microsoft Excel files, containing the raw measurements of pore size and of L and d (as defined in the manuscript) for calculation of percolation diameter. Units are in pixels unless specified. Zip folder containing raw images (.png files) of each scaffold se...

  10. Restricted VH/VL usage and limited mutations in gluten-specific IgA of coeliac disease lesion plasma cells. (United States)

    Steinsbø, Øyvind; Henry Dunand, Carole J; Huang, Min; Mesin, Luka; Salgado-Ferrer, Marlene; Lundin, Knut E A; Jahnsen, Jørgen; Wilson, Patrick C; Sollid, Ludvig M


    Coeliac disease (CD), an enteropathy caused by cereal gluten ingestion, is characterized by CD4(+) T cells recognizing deamidated gluten and by antibodies reactive to gluten or the self-antigen transglutaminase 2 (TG2). TG2-specific immunoglobulin A (IgA) of plasma cells (PCs) from CD lesions have limited somatic hypermutation (SHM). Here we report that gluten-specific IgA of lesion-resident PCs share this feature. Monoclonal antibodies were expression cloned from single PCs of patients either isolated from cultures with reactivity to complex deamidated gluten antigen or by sorting with gluten peptide tetramers. Typically, the antibodies bind gluten peptides related to T-cell epitopes and many have higher reactivity to deamidated peptides. There is restricted VH and VL combination and usage among the antibodies. Limited SHM suggests that a common factor governs the mutation level in PCs producing TG2- and gluten-specific IgA. The antibodies have potential use for diagnosis of CD and for detection of gluten.

  11. Reply to "Comment on 'Modeling of electrode polarization for electrolytic cells with a limited ionic adsorption' ". (United States)

    Sawada, Atsushi


    The dielectric properties of dilute electrolytic solution cells have been measured in a low-frequency region, and the dielectric spectra have been analyzed in terms of space-charge polarization by using the Nernst-Planck (NP) model in the presence of ionic adsorption on electrodes [Phys. Rev. E 88, 032406 (2013)]. In the NP model, the internal electric field of the cell is considered to be approximately equal to the external field. In a Comment by Alexe-Ionescu et al. [Phys. Rev. E 89, 056401 (2014).] on our paper [Phys. Rev. E 88, 032406 (2013)], they claim the invalidity of the NP model and the necessity of the conventional Poisson-Nernst-Planck (PNP) model for the data analysis. Their criticisms are, however, originated from a viewpoint for determining the internal electric field, that is different from our approach. In this Reply, we show the validity of the NP model referring to our previous paper in which the conventional PNP model has been modified so as to correctly describe the actual internal field.

  12. A case of limbic encephalitis presenting as a paraneoplastic manifestation of limited stage small cell lung cancer: a case report

    Directory of Open Access Journals (Sweden)

    Butt Mohammad


    Full Text Available Abstract Introduction The differential diagnosis of altered mental status and behavioral change is very extensive. Paraneoplastic limbic encephalitis is a rare cause of cognitive impairment, which should be considered in the differential diagnosis. Case presentation A 64-year-old British Caucasian woman presented to our hospital with a 12-week history of confusion and short-term memory loss. She was hyponatremic with a serum sodium level of 128mmol/L. Moreover, there was evidence of left hilar prominence on the chest radiograph. A thoracic computed tomography scan showed left hilar opacity with confluent lymphadenopathy. A percutaneous biopsy confirmed a diagnosis of small cell lung cancer. There was no radiological evidence of brain metastasis on the computed tomography scan. In view of continued cognitive impairment, which was felt to be disproportionate to hyponatremia, a magnetic resonance imaging scan of the brain was undertaken. It showed hyperintense signals from both hippocampi, highly suggestive of limbic encephalitis presenting as a paraneoplastic manifestation of small cell lung cancer. She had a significant radiological and clinical response following chemotherapy and radiotherapy. Conclusion This case highlights the importance of considering paraneoplastic syndromes in patients with neurological symptoms in the context of lung malignancy. If initial investigations fail to reveal the cause of cognitive impairment in a patient with malignancy, magnetic resonance imaging may be invaluable in the diagnosis of limbic encephalitis. The clinical presentation, diagnostic techniques and management of paraneoplastic limbic encephalitis are discussed in this case report.

  13. Experimental Investigation and Discussion on the Mechanical Endurance Limit of Nafion Membrane Used in Proton Exchange Membrane Fuel Cell

    Directory of Open Access Journals (Sweden)

    Yang Xiao


    Full Text Available As a solution of high efficiency and clean energy, fuel cell technologies, especially proton exchange membrane fuel cell (PEMFC, have caught extensive attention. However, after decades of development, the performances of PEMFCs are far from achieving the target from the Department of Energy (DOE. Thus, further understanding of the degradation mechanism is needed to overcome this obstacle. Due to the importance of proton exchange membrane in a PEMFC, the degradation of the membrane, such as hygrothermal aging effect on its properties, are particularly necessary. In this work, a thick membrane (Nafion N117, which is always used as an ionic polymer for the PEMFCs, has been analyzed. Experimental investigation is performed for understanding the mechanical endurance of the bare membranes under different loading conditions. Tensile tests are conducted to compare the mechanical property evolution of two kinds of bare-membrane specimens including the dog-bone and the deeply double edge notched (DDEN types. Both dog-bone and DDEN specimens were subjected to a series of degradation tests with different cycling times and wide humidity ranges. The tensile tests are repeated for both kinds of specimens to assess the strain-stress relations. Furthermore, Fourier transform infrared spectroscopy (FT-IR, X-ray diffraction (XRD and Scanning electron microscope (SEM observation and water absorption measurement were conducted to speculate the cause of this variation. The initial cracks along with the increasing of bound water content were speculated as the primary cause.

  14. Influence of grain boundary modification on limited performance of wide bandgap Cu(In,Ga)Se2 solar cells (United States)

    Raghuwanshi, M.; Cadel, E.; Pareige, P.; Duguay, S.; Couzinie-Devy, F.; Arzel, L.; Barreau, N.


    The reason why so-called wide-bandgap CuIn1-xGaxSe2 (CIGSe with x > 0.4) based solar cells show hindered performance compared with theoretical expectations is still a matter of debate. In the present Letter, atom probe tomography studies of CuIn1-xGaxSe2 polycrystalline thin films with x varying from 0 to 1 are reported. These investigations confirm that the grain boundaries (GBs) of low gallium containing (x CIGSe layers are Cu-depleted compared with grains interior (GI). In contrast, it is observed that the GBs of widest band gap CIGSe films (x > 0.8) are Cu-enriched compared with GI. For intermediate gallium contents (0.4 < x < 0.8), both types of GBs are detected. This threshold value of 0.4 surprisingly coincides with solar cells output voltage deviation from theoretical expectations, which suggests modifications of GBs properties could participate in the loss of photovoltaic performance.

  15. Influence of grain boundary modification on limited performance of wide bandgap Cu(In,Ga)Se{sub 2} solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Raghuwanshi, M., E-mail:; Cadel, E.; Pareige, P.; Duguay, S. [Groupe de Physique des Materiaux (GPM), UMR 6634 CNRS, Université et INSA de Rouen, Avenue de l' Universite BP 12, 76801 Saint Etienne du Rouvray (France); Couzinie-Devy, F.; Arzel, L.; Barreau, N. [Institut des Materiaux Jean Rouxel (IMN), UMR 6502 CNRS, Université de Nantes, 2 rue de la Houssiniere BP 32229, 44322 Nantes cedex 3 (France)


    The reason why so-called wide-bandgap CuIn{sub 1−x}Ga{sub x}Se{sub 2} (CIGSe with x > 0.4) based solar cells show hindered performance compared with theoretical expectations is still a matter of debate. In the present Letter, atom probe tomography studies of CuIn{sub 1−x}Ga{sub x}Se{sub 2} polycrystalline thin films with x varying from 0 to 1 are reported. These investigations confirm that the grain boundaries (GBs) of low gallium containing (x < 0.4) CIGSe layers are Cu-depleted compared with grains interior (GI). In contrast, it is observed that the GBs of widest band gap CIGSe films (x > 0.8) are Cu-enriched compared with GI. For intermediate gallium contents (0.4 < x < 0.8), both types of GBs are detected. This threshold value of 0.4 surprisingly coincides with solar cells output voltage deviation from theoretical expectations, which suggests modifications of GBs properties could participate in the loss of photovoltaic performance.

  16. Development and Validation of Non-Integrative, Self-Limited, and Replicating Minicircles for Safe Reporter Gene Imaging of Cell-Based Therapies (United States)

    Ronald, John A.; Cusso, Lorena; Chuang, Hui-Yen; Yan, Xinrui; Dragulescu-Andrasi, Anca; Gambhir, Sanjiv Sam


    Reporter gene (RG) imaging of cell-based therapies provides a direct readout of therapeutic efficacy by assessing the fate of implanted cells. To permit long-term cellular imaging, RGs are traditionally required to be integrated into the cellular genome. This poses a potential safety risk and regulatory bottleneck for clinical translation as integration can lead to cellular transformation. To address this issue, we have developed non-integrative, replicating minicircles (MCs) as an alternative platform for safer monitoring of cells in living subjects. We developed both plasmids and minicircles containing the scaffold/matrix attachment regions (S/MAR) of the human interferon-beta gene, driven by the CMV promoter, and expressing the bioluminescence RG firefly luciferase. Constructs were transfected into breast cancer cells, and expanded S/MAR minicircle clones showed luciferase signal for greater than 3 months in culture and minicircles remained as episomes. Importantly, luciferase activity in clonal populations was slowly lost over time and this corresponded to a loss of episome, providing a way to reversibly label cells. To monitor cell proliferation in vivo, 1.5×106 cells carrying the S/MAR minicircle were implanted subcutaneously into mice (n = 5) and as tumors developed significantly more bioluminescence signal was noted at day 35 and 43 compared to day 7 post-implant (p<0.05). To our knowledge, this is the first work examining the use of episomal, self-limited, replicating minicircles to track the proliferation of cells using non-invasive imaging in living subjects. Continued development of S/MAR minicircles will provide a broadly applicable vector platform amenable with any of the numerous RG technologies available to allow therapeutic cell fate to be assessed in individual patients, and to achieve this without the need to manipulate the cell's genome so that safety concerns are minimized. This will lead to safe tools to assess treatment response at

  17. Predictors of general discomfort, limitations in activities of daily living and intention of a second donation in unrelated hematopoietic stem cell donation. (United States)

    Lee, M H; Jang, J H; Min, H J; Jang, H I; Nah, J H; Lyu, C J; Han, K-S; Won, J H; Lee, Y-H; Chong, S Y; Mun, Y C; Lee, W S; Kim, S J; Kim, I


    We performed a retrospective study of 1868 consecutive unrelated donors to predict the risk factors related to general discomfort, limitations in activities of daily living (ADLs) and intention of a second donation in hematopoietic stem cell (HSC) donation. General discomfort and limitations in ADLs were assessed by numerical measurement (scores of 0-10) and donor's intention of a second donation by yes or no reply. The post-donation questionnaires were completed within 48 h after HSC collection and at 1 week, 4 weeks, and 4 months thereafter. Predictors of general discomfort included female sex (Pdonation on day 1 (Pdonation on day 1 (Pdonation was male sex (P=0.0007). Age, sex and collection method and period should be considered risk factors when unrelated HSC donation is performed.

  18. Inverse Limits

    CERN Document Server

    Ingram, WT


    Inverse limits provide a powerful tool for constructing complicated spaces from simple ones. They also turn the study of a dynamical system consisting of a space and a self-map into a study of a (likely more complicated) space and a self-homeomorphism. In four chapters along with an appendix containing background material the authors develop the theory of inverse limits. The book begins with an introduction through inverse limits on [0,1] before moving to a general treatment of the subject. Special topics in continuum theory complete the book. Although it is not a book on dynamics, the influen

  19. From invasion to latency: intracellular noise and cell motility as key controls of the competition between resource-limited cellular populations

    KAUST Repository

    Guerrero, Pilar


    © 2015, Springer-Verlag Berlin Heidelberg. In this paper we analyse stochastic models of the competition between two resource-limited cell populations which differ in their response to nutrient availability: the resident population exhibits a switch-like response behaviour while the invading population exhibits a bistable response. We investigate how noise in the intracellular regulatory pathways and cell motility influence the fate of the incumbent and invading populations. We focus initially on a spatially homogeneous system and study in detail the role of intracellular noise. We show that in such well-mixed systems, two distinct regimes exist: In the low (intracellular) noise limit, the invader has the ability to invade the resident population, whereas in the high noise regime competition between the two populations is found to be neutral and, in accordance with neutral evolution theory, invasion is a random event. Careful examination of the system dynamics leads us to conclude that (i) even if the invader is unable to invade, the distribution of survival times, PS(t), has a fat-tail behaviour (PS(t)∼t-1) which implies that small colonies of mutants can coexist with the resident population for arbitrarily long times, and (ii) the bistable structure of the invading population increases the stability of the latent population, thus increasing their long-term likelihood of survival, by decreasing the intensity of the noise at the population level. We also examine the effects of spatial inhomogeneity. In the low noise limit we find that cell motility is positively correlated with the aggressiveness of the invader as defined by the time the invader takes to invade the resident population: the faster the invasion, the more aggressive the invader.

  20. Water vapour emission in vegetable fuel: absorption cell measurements and detection limits of our CO II Dial system (United States)

    Bellecci, C.; De Leo, L.; Gaudio, P.; Gelfusa, M.; Lo Feudo, T.; Martellucci, S.; Richetta, M.


    Forest fires can be the cause of serious environmental and economic damages. For this reason a considerable effort has been directed toward the forest protection and fire fighting. In the early forest fire detection, Lidar technique present considerable advantages compared to the passive detection methods based on infrared cameras currently in common use, due its higher sensitivity and ability to accurately locate the fire. The combustion phase of the vegetable matter causes a great amount of water vapour emission, thus the water molecule behaviour will be studied to obtain a fire detection system ready and efficient also before the flame propagation. A first evaluation of increment of the water vapour concentration compared to standard one will be estimated by a numerical simulation. These results will be compared with the experimental measurements carried out into a cell with a CO II Dial system, burning different kinds of vegetable fuel. Our results and their comparison will be reported in this paper.

  1. Process limitations of a whole-cell P450 catalyzed reaction using a CYP153A-CPR fusion construct expressed in Escherichia coli

    DEFF Research Database (Denmark)

    Lundemo, M. T.; Notonier, S.; Striedner, G.;


    fatty acids at the terminal position. ω-Hydroxylated fatty acids can be used in the field of high-end polymers and in the cosmetic and fragrance industry. Here, we have identified the limitations for implementation of a whole-cell P450-catalyzed reaction by characterizing the chosen biocatalyst as well......Cytochrome P450s are interesting biocatalysts due to their ability to hydroxylate non-activated hydrocarbons in a selective manner. However, to date only a few P450-catalyzed processes have been implemented in industry due to the difficulty of developing economically feasible processes...

  2. Spatial distribution and dynamics of proton conductivity in fuel cell membranes: potential and limitations of electrochemical atomic force microscopy measurements. (United States)

    Aleksandrova, E; Hink, S; Hiesgen, R; Roduner, E


    The proton conductivity of a Nafion 112 membrane is measured with a high spatial resolution using electrochemical atomic force microscopy. Image analysis reveals an inhomogeneous conductivity distribution which is attributed to the limited connectivity of hydrophilic domains. This information relates to the micro-morphology which is due to phase separation of the hydrophobic polymer backbone and the hydrophilic pendant groups. The direct images relate to a different length scale and are complementary to the x-ray diffraction investigations which provide only average information. Furthermore, the measured current values reveal an interesting correlation with the size of the conductive areas. A bimodal conductivity distribution suggests that there are different mechanisms which contribute to the proton current in Nafion. Additionally, time dependence in local conductivity is found and interpreted in terms of redistribution of water in the membrane. A statistical analysis of the current distribution is performed and compared with theoretical simulations. Evidence is found for the existence of a critical current density. On a timescale of seconds the response of the conductive network is probed by applying voltage steps to the atomic force microscope tip.

  3. Transient inhibition of ROR-γt therapeutically limits intestinal inflammation by reducing TH17 cells and preserving group 3 innate lymphoid cells. (United States)

    Withers, David R; Hepworth, Matthew R; Wang, Xinxin; Mackley, Emma C; Halford, Emily E; Dutton, Emma E; Marriott, Clare L; Brucklacher-Waldert, Verena; Veldhoen, Marc; Kelsen, Judith; Baldassano, Robert N; Sonnenberg, Gregory F


    RAR-related orphan receptor-γt (ROR-γt) directs differentiation of proinflammatory T helper 17 (TH17) cells and is a potential therapeutic target in chronic autoimmune and inflammatory diseases. However, ROR-γt-dependent group 3 innate lymphoid cells ILC3s provide essential immunity and tissue protection in the intestine, suggesting that targeting ROR-γt could also result in impaired host defense after infection or enhanced tissue damage. Here, we demonstrate that transient chemical inhibition of ROR-γt in mice selectively reduces cytokine production from TH17 but not ILCs in the context of intestinal infection with Citrobacter rodentium, resulting in preserved innate immunity. Temporal deletion of Rorc (encoding ROR-γt) in mature ILCs also did not impair cytokine response in the steady state or during infection. Finally, pharmacologic inhibition of ROR-γt provided therapeutic benefit in mouse models of intestinal inflammation and reduced the frequency of TH17 cells but not ILCs isolated from primary intestinal samples of individuals with inflammatory bowel disease (IBD). Collectively, these results reveal differential requirements for ROR-γt in the maintenance of TH17 cell and ILC3 responses and suggest that transient inhibition of ROR-γt is a safe and effective therapeutic approach during intestinal inflammation.

  4. Oxygen Partial Pressure Is a Rate-Limiting Parameter for Cell Proliferation in 3D Spheroids Grown in Physioxic Culture Condition. (United States)

    Gomes, Aurélie; Guillaume, Ludivine; Grimes, David Robert; Fehrenbach, Jérôme; Lobjois, Valérie; Ducommun, Bernard


    The in situ oxygen partial pressure in normal and tumor tissues is in the range of a few percent. Therefore, when studying cell growth in 3D culture systems, it is essential to consider how the physiological oxygen concentration, rather than the one in the ambient air, influences the proliferation parameters. Here, we investigated the effect of reducing oxygen partial pressure from 21% to 5% on cell proliferation rate and regionalization in a 3D tumor spheroid model. We found that 5% oxygen concentration strongly inhibited spheroid growth, changed the proliferation gradient and reduced the 50% In Depth Proliferation index (IDP50), compared with culture at 21% oxygen. We then modeled the oxygen partial pressure profiles using the experimental data generated by culturing spheroids in physioxic and normoxic conditions. Although hypoxia occurred at similar depth in spheroids grown in the two conditions, oxygen partial pressure was a major rate-limiting factor with a critical effect on cell proliferation rate and regionalization only in spheroids grown in physioxic condition and not in spheroids grown at atmospheric normoxia. Our findings strengthen the need to consider conducting experiment in physioxic conditions (i.e., tissue normoxia) for proper understanding of cancer cell biology and the evaluation of anticancer drugs in 3D culture systems.

  5. Hepatitis C Virus Sensing by Human Trophoblasts Induces Innate Immune Responses and Recruitment of Maternal NK Cells: Potential Implications for Limiting Vertical Transmission. (United States)

    Giugliano, Silvia; Petroff, Margaret G; Warren, Bryce D; Jasti, Susmita; Linscheid, Caitlin; Ward, Ashley; Kramer, Anita; Dobrinskikh, Evgenia; Sheiko, Melissa A; Gale, Michael; Golden-Mason, Lucy; Winn, Virginia D; Rosen, Hugo R


    Hepatitis C virus (HCV) is the world's most common blood-borne viral infection for which there is no vaccine. The rates of vertical transmission range between 3 and 6% with odds 90% higher in the presence of HIV coinfection. Prevention of vertical transmission is not possible because of lack of an approved therapy for use in pregnancy or an effective vaccine. Recently, HCV has been identified as an independent risk factor for preterm delivery, perinatal mortality, and other complications. In this study, we characterized the immune responses that contribute to the control of viral infection at the maternal-fetal interface (MFI) in the early gestational stages. In this study, we show that primary human trophoblast cells and an extravillous trophoblast cell line (HTR8), from first and second trimester of pregnancy, express receptors relevant for HCV binding/entry and are permissive for HCV uptake. We found that HCV-RNA sensing by human trophoblast cells induces robust upregulation of type I/III IFNs and secretion of multiple chemokines that elicit recruitment and activation of decidual NK cells. Furthermore, we observed that HCV-RNA transfection induces a proapoptotic response within HTR8 that could affect the morphology of the placenta. To our knowledge, for the first time, we demonstrate that HCV-RNA sensing by human trophoblast cells elicits a strong antiviral response that alters the recruitment and activation of innate immune cells at the MFI. This work provides a paradigm shift in our understanding of HCV-specific immunity at the MFI as well as novel insights into mechanisms that limit vertical transmission but may paradoxically lead to virus-related pregnancy complications.

  6. Mast Cells: Key Players in the Shadow in Oral Inflammation and in Squamous Cell Carcinoma of the Oral Cavity (United States)

    Gaje, Pusa Nela; Amalia Ceausu, Raluca; Jitariu, Adriana; Popovici, Ramona Amina; Raica, Marius


    Although mast cells (MCs) have been discovered over 130 years ago, their function was almost exclusively linked to allergic affections. At the time being, it is well known that MCs possess a great variety of roles, in both physiologic and pathologic conditions. In the oral tissues, MCs release different proinflammatory cytokines, tumor necrosis factor alpha (TNF-α), that promote leukocyte infiltration in various inflammatory states of the oral cavity. These cells play a key role in the inflammatory process and, as a consequence, their number changes in different pathologic conditions of the oral cavity, like gingivitis, periodontitis, and so on. MCs also represent a rich source of proteases, especially of mast cell tryptase and chymase, which directly degrade the extracellular matrix through their proteolytic activity and thus indirectly stimulate angiogenesis and facilitate invasion and metastasis. It may be stated that mast cells could have an impact on primary tumor development, progression, and metastases in oral squamous cell carcinoma. By understanding the role of mast cells in the pathogenesis of different inflammatory and tumor diseases of the oral cavity, these cells may become therapeutic targets that could possibly improve the prognosis and survival of these patients. PMID:27847826

  7. Immunization with Neospora caninum profilin induces limited protection and a regulatory T-cell response in mice. (United States)

    Mansilla, Florencia Celeste; Quintana, María Eugenia; Langellotti, Cecilia; Wilda, Maximiliano; Martinez, Andrea; Fonzo, Adriana; Moore, Dadín Prando; Cardoso, Nancy; Capozzo, Alejandra Victoria


    Profilins are actin-binding proteins that regulate the polymerization of actin filaments. In apicomplexan parasites, they are essential for invasion. Profilins also trigger the immune response of the host by activating TLRs on dendritic cells (DCs), inducing the production of pro-inflammatory cytokines. In this study we characterized for the first time the immune response and protection elicited by a vaccine based on Neospora caninum profilin in mice. Groups of eight BALB/c mice received either two doses of a recombinant N. caninum profilin expressed in Escherichia coli. (rNcPRO) or PBS, both formulated with an aqueous soy-based adjuvant enriched in TLR-agonists. Specific anti-profilin antibodies were detected in rNcPRO-vaccinated animals, mainly IgM and IgG3, which were consumed after infection. Splenocytes from rNcPRO-immunized animals proliferated after an in vitro stimulation with rNcPRO before and after challenge. An impairment of the cellular response was observed in NcPRO vaccinated and infected mice following an in vitro stimulation with native antigens of N. caninum, related to an increase in the percentage of CD4+CD25+FoxP3+. Two out of five rNcPRO-vaccinated challenged mice were protected; they were negative for parasite DNA in the brain and showed no histopathological lesions, which were found in all PBS-vaccinated animals. As a whole, our results provide evidence of a regulatory response elicited by immunization with rNcPRO, and suggest a role of profilin in the modulation and/or evasion of immune responses against N. caninum.

  8. Evaluation of Macular Retinal Ganglion Cell-Inner Plexiform Layer Thickness after Vitrectomy with Internal Limiting Membrane Peeling for Idiopathic Macular Holes

    Directory of Open Access Journals (Sweden)

    Alfonso L. Sabater


    Full Text Available Purpose. To evaluate macular retinal ganglion cell-inner plexiform layer (GCIPL thickness changes after Brilliant Blue G-assisted internal limiting membrane peeling for idiopathic macular hole repair using a high-resolution spectral-domain optical coherence tomography (SD-OCT. Methods. 32 eyes from 32 patients with idiopathic macular holes who underwent vitrectomy with internal limiting membrane peeling between January 2011 and July 2012 were retrospectively analyzed. GCIPL thickness was measured before surgery, and at one month and at six months after surgery. Values obtained from automated and semimanual SD-OCT segmentation analysis were compared (Cirrus HD-OCT, Carl Zeiss Meditec, Dublin, CA. Results. No significant differences were found between average GCIPL thickness values between preoperative and postoperative analysis. However, statistical significant differences were found in GCIPL thickness at the temporal macular quadrants at six months after surgery. Quality measurement analysis performed by automated segmentation revealed a significant number of segmentation errors. Semimanual segmentation slightly improved the quality of the results. Conclusion. SD-OCT analysis of GCIPL thickness found a significant reduction at the temporal macular quadrants at 6 months after Brilliant Blue G-assisted internal limiting membrane peeling for idiopathic macular hole.

  9. Evaluation of Macular Retinal Ganglion Cell-Inner Plexiform Layer Thickness after Vitrectomy with Internal Limiting Membrane Peeling for Idiopathic Macular Holes (United States)

    Velázquez-Villoria, Álvaro; Zapata, Miguel A.; Figueroa, Marta S.; Suárez-Leoz, Marta; Arrevola, Luis; Teijeiro, María-Ángeles; García-Layana, Alfredo


    Purpose. To evaluate macular retinal ganglion cell-inner plexiform layer (GCIPL) thickness changes after Brilliant Blue G-assisted internal limiting membrane peeling for idiopathic macular hole repair using a high-resolution spectral-domain optical coherence tomography (SD-OCT). Methods. 32 eyes from 32 patients with idiopathic macular holes who underwent vitrectomy with internal limiting membrane peeling between January 2011 and July 2012 were retrospectively analyzed. GCIPL thickness was measured before surgery, and at one month and at six months after surgery. Values obtained from automated and semimanual SD-OCT segmentation analysis were compared (Cirrus HD-OCT, Carl Zeiss Meditec, Dublin, CA). Results. No significant differences were found between average GCIPL thickness values between preoperative and postoperative analysis. However, statistical significant differences were found in GCIPL thickness at the temporal macular quadrants at six months after surgery. Quality measurement analysis performed by automated segmentation revealed a significant number of segmentation errors. Semimanual segmentation slightly improved the quality of the results. Conclusion. SD-OCT analysis of GCIPL thickness found a significant reduction at the temporal macular quadrants at 6 months after Brilliant Blue G-assisted internal limiting membrane peeling for idiopathic macular hole. PMID:25110679

  10. Use of age and CD4 cell count as criteria for identification of recent HIV infection in resource-limited countries

    Directory of Open Access Journals (Sweden)

    M Penazzato


    Full Text Available Background: Identification of recent HIV infection is crucial for estimating HIV incidence and transmitted drug resistance (TDR prevalence. Due to limited availability of diagnostic assays, WHO TDR surveys use age <25 yrs and/or CD4 >500 cells/mm3 at HIV diagnosis as epidemiological criteria to maximize inclusion of recently infected (within 3 yrs and ARV-naïve individuals. Accuracy of these criteria and variation by geographical region is unknown. Methods: A literature review of studies on HIV seroconverters (SC published through March 2012 was performed. Age at SC and CD4 decline in absence of treatment were abstracted. Accuracy of alternative TDR survey criteria was explored. Results: 11 studies provided age at SC: 7 in Africa, 2 in Latin America, 2 in Asia. Median age at SC ranged between 24 and 33 years in studies in Kenya and Zambia, respectively and was 29 [interquantile range (IQR 24, 34] in a large cohort study from Africa. Median age at SC was 29 years in studies on MSM in Brazil and China. 7 studies reported CD4 count decline: 5 in Africa, 1 in Latin America and 1 in Asia. Studies used ordinary least square regression or mixed models. None described median CD4 count 3 yrs after SC. The estimated mean CD4 count 3 yrs after SC ranged from 350–420 cells/mm3 in Africa and was 237 and 282 cells/mm3 in Asia and Latin America, respectively. Conclusion: HIV SC occurs at all ages (median 29 yrs in the assessed geographical regions. Enhancing feasibility of TDR survey implementation by including individuals >25 yrs decreases specificity, particularly in low HIV prevalence settings (Table.Use of age <25 yrs can maximized specificity to detect recent infection, but misses almost 75% of recent infections thus limiting feasibility of TDR survey implementation, particularly in low HIV prevalence settings. Lower mean CD4 count 3 yrs after SC was observed in Asia and Latin America compared to Africa. Regional differences may be explained by

  11. Allo-reactivity of mesenchymal stem cells in rhesus macaques is dose and haplotype dependent and limits durable cell engraftment in vivo.

    Directory of Open Access Journals (Sweden)

    Iryna A Isakova

    Full Text Available The emerging paradigm that MSCs are immune privileged has fostered the use of "off-the-shelf" allogeneic MSC-based therapies in human clinical trials. However, this approach ignores studies in experimental animals wherein transplantation of MSCs across MHC boundaries elicits measurable allo-immune responses. To determine if MSCs are hypo-immunogeneic, we characterized the immune response in rhesus macaques following intracranial administration of allogeneic vs. autologous MSCs. This analysis revealed unambiguous evidence of productive allo-recognition based on expansion of NK, B and T cell subsets in peripheral blood and detection of allo-specific antibodies in animals administered allogeneic but not autologous MSCs. Moreover, the degree of MHC class I and II mismatch between the MSC donor and recipient significantly influenced the magnitude and nature of the allo-immune response. Consistent with these findings, real-time PCR analysis of brain tissue from female recipients administered varying doses of male, allogeneic MSCs revealed a significant inverse correlation between MSC engraftment levels and cell dose. Changes in post-transplant neutrophil and lymphocyte counts also correlated with dose and were predictive of overall MSC engraftment levels. However, secondary antigen challenge failed to elicit a measurable immune response in allogeneic recipients. Finally, extensive behavior testing of animals revealed no main effect of cell dose on motor skills, social development, or temperament. Collectively, these data indicate that allogeneic MSCs are weakly immunogenic when transplanted across MHC boundaries in rhesus macaques and this negatively impacts durable engraftment levels. Therefore the use of unrelated donor MSCs should be carefully evaluated in human patients.

  12. The use of NH4(+) rather than NO3(-) affects cell stoichiometry, C allocation, photosynthesis and growth in the cyanobacterium Synechococcus sp. UTEX LB 2380, only when energy is limiting. (United States)

    Ruan, Zuoxi; Giordano, Mario


    The assimilation of N-NO3(-) requires more energy than that of N-NH4(+) . This becomes relevant when energy is limiting and may impinge differently on cell energy budget depending on depth, time of the day and season. We hypothesize that N-limited and energy-limited cells of the oceanic cyanobacterium Synechococcus sp. differ in their response to the N source with respect to growth, elemental stoichiometry and carbon allocation. Under N limitation, cells retained almost absolute homeostasis of elemental and organic composition, and the use of NH4(+) did not stimulate growth. When energy was limiting, however, Synechococcus grew faster in NH4(+) than in NO3(-) and had higher C (20%), N (38%) and S (30%) cell quotas. Furthermore, more C was allocated to protein, whereas the carbohydrate and lipid pool size did not change appreciably. Energy limitation also led to a higher photosynthetic rate relative to N limitation. We interpret these results as an indication that, under energy limitation, the use of the least expensive N source allowed a spillover of the energy saved from N assimilation to the assimilation of other nutrients. The change in elemental stoichiometry influenced C allocation, inducing an increase in cell protein, which resulted in a stimulation of photosynthesis and growth.

  13. Heterogeneity of mast cells and expression of Annexin A1 protein in a second degree burn model with silver sulfadiazine treatment (United States)

    Souza, Helena Ribeiro; de Azevedo, Lucas Ribeiro; Possebon, Lucas; Costa, Sara de Souza; Iyomasa-Pilon, Melina Mizusaki; Oliani, Sonia Maria; Girol, Ana Paula


    Mast cells (MCs) participate in all stages of skin healing and one of their mediators is the Annexin A1 protein (AnxA1), linked to inflammation, proliferation, migration and apoptosis processes, but not studied in thermal burns yet. Therefore, our objectives were to evaluate the behavior of MCs and AnxA1 in a second degree burn model, treated or not with silver sulfadiazine 1% (SDP 1%) and associated to macrophages quantification and cytokines dosages. MCs counts showed few cells in the early stages of repair but increased MCs in the final phases in the untreated group. The normal skin presented numerous tryptase-positive MCs that were reduced after burning in all analyzed periods. Differently, few chymase-positive MCs were observed in the early stages of healing, however, increased chymase-positive MCs were found at the final phase in the untreated group. MCs also showed high immunoreactivity for AnxA1 on day 3 in both groups. In the tissue there was a strong protein expression in the early stages of healing, but in the final phases only in the SDP treated animals. TNF-α, IL-1β, IL-6, IL-10 and MCP-1 levels and macrophages quantification were increased in inflammation and reepithelialization phases. Reduced IL-1β, IL-6 and IL-10 levels and numerous macrophages occurred in the treated animals during tissue repair. Our results indicate modulation in the profile of MCs and AnxA1expression during healing by the treatment with SDP 1%, pointing them as targets for therapeutic interventions on skin burns. PMID:28278234

  14. Application of the revised Tumour Node Metastasis (TNM) staging system of clear cell renal cell carcinoma in eastern China: advantages and limitations

    Institute of Scientific and Technical Information of China (English)

    Chao Qin; Li-Jiang Sun; Li Cui; Qiang Cao; Jian Zhu; Pu Li; Gui-Ming Zhang


    This study was designed to evaluate whether the revised 2010 Tumour Node Metastasis (TNM) staging system could lead to a more accurate prediction of the prognosis of renal cell carcinoma (RCC) patients.A total of 1216 patients who had undergone radical nephrectomy or partial nephrectomy for RCC from 2003 to 2011 were enrolled.All of the patients had pathologically confirmed clear cell RCC (ccRCC).All cases were staged by both the 2002 and 2010 TNM staging systems after pathological review,and survival data were collected.Univariate and multivariate Cox regression models were used to evaluate cancer-specific survival (CSS) and progression-free survival (PFS) after surgery.Continuous variables,such as age and tumour diameter,were calculated as mean values and standard deviations (s.d.) or as median values.Survival was calculated by the Kaplan-Meier method,and the log-rank test assessed differences between groups.Statistically significant differences in CSS and PFS were noted among patients in T3 subgroups using the new 2010 staging system.Therefore,the revised 2010 TNM staging system can lead to a more accurate prediction of the prognosis of ccRCC patients.However,when using the revised 2010 staging system,we found that more than 92% of patients (288/313) with T3 tumours were staged in the T3a subgroup,and their survival data were not significantly different from those of patients with T2b tumours.In addition,T2 subclassification failed to independently predict survival in RCC patients.

  15. Interleukin 4-producing CD4+ T cells in the skin of cats with allergic dermatitis. (United States)

    Roosje, P J; Dean, G A; Willemse, T; Rutten, V P M G; Thepen, T


    Lesional skin of cats with allergic dermatitis has a cellular infiltrate and a CD4/CD8 ratio comparable to that in humans with atopic dermatitis. CD4+ helper T cells and in particular cells belonging to the Th2 subset play an important role in disease pathogenesis in humans. We investigated the cytokine pattern of CD4+ T cells in situ, with special emphasis on the putative presence of cells producing interleukin 4 (IL4), in cats with allergic dermatitis. Immunohistochemical procedures were used to determine that CD4+ T cells in lesional and nonlesional skin of cats with allergic dermatitis can produce IL4, as occurs in humans. Lesional and nonlesional skin of cats with allergic dermatitis had significantly more IL4+ T cells (P = 0.001) than did skin of healthy control cats. Double staining indicated that all IL4+ cells were positive for pan-T or CD4 markers. Double labeling for mast cell chymase and IL4 stained primarily different cells. Western blotting demonstrated cross-reactivity between the antibody against human IL4 and a feline recombinant IL4. These results indicate that IL4 is primarily produced by CD4+ T cells and is also present in clinically uninvolved skin, indicating a role in the pathogenesis of allergic dermatitis in cats.

  16. Mast cell subsets and neuropeptides in leprosy reactions

    Directory of Open Access Journals (Sweden)

    Antunes Sérgio Luiz Gomes


    Full Text Available The immunohistochemical identification of neuropeptides (calcitonin gene-related peptide, vasoactive intestinal polypeptide, substance P, alpha-melanocyte stimulating hormone and gamma-melanocyte stimulating hormone quantification of mast cells and their subsets (tryptase/chymase-immunoreactive mast cells = TCMC and tryptase-immunoreactive mast cells = TMC were determined in biopsies of six patients with leprosy reactions (three patients with type I reaction and three with type II. Biopsies were compared with those taken from the same body site in the remission stage of the same patient. We found a relative increase of TMC in the inflammatory infiltrate of the reactional biopsies compared to the post-reactional biopsy. Also, the total number of mast cells and the TMC/TCMC ratio in the inflammatory infiltrate was significantly higher than in the intervening dermis of the biopsies of both periods. No significant difference was found regarding neuroptide expression in the reactional and post-reactional biopsies. The relative increase of TMC in the reactional infiltrates could implicate this mast cell subset in the reported increase of the immune response in leprosy reactions.

  17. Phenylalanine and tyrosine levels are rate-limiting factors in production of health promoting metabolites in Vitis vinifera cv. Gamay Red cell suspension. (United States)

    Manela, Neta; Oliva, Moran; Ovadia, Rinat; Sikron-Persi, Noga; Ayenew, Biruk; Fait, Aaron; Galili, Gad; Perl, Avichai; Weiss, David; Oren-Shamir, Michal


    Environmental stresses such as high light intensity and temperature cause induction of the shikimate pathway, aromatic amino acids (AAA) pathways, and of pathways downstream from AAAs. The induction leads to production of specialized metabolites that protect the cells from oxidative damage. The regulation of the diverse AAA derived pathways is still not well understood. To gain insight on that regulation, we increased AAA production in red grape Vitis vinifera cv. Gamay Red cell suspension, without inducing external stress on the cells, and characterized the metabolic effect of this induction. Increased AAA production was achieved by expressing a feedback-insensitive bacterial form of 3-deoxy- D-arabino-heptulosonate 7-phosphate synthase enzyme (AroG (*)) of the shikimate pathway under a constitutive promoter. The presence of AroG(*) protein led to elevated levels of primary metabolites in the shikimate and AAA pathways including phenylalanine and tyrosine, and to a dramatic increase in phenylpropanoids. The AroG (*) transformed lines accumulated up to 20 and 150 fold higher levels of resveratrol and dihydroquercetin, respectively. Quercetin, formed from dihydroquercetin, and resveratrol, are health promoting metabolites that are induced due to environmental stresses. Testing the expression level of key genes along the stilbenoids, benzenoids, and phenylpropanoid pathways showed that transcription was not affected by AroG (*). This suggests that concentrations of AAAs, and of phenylalanine in particular, are rate-limiting in production of these metabolites. In contrast, increased phenylalanine production did not lead to elevated concentrations of anthocyanins, even though they are also phenylpropanoid metabolites. This suggests a control mechanism of this pathway that is independent of AAA concentration. Interestingly, total anthocyanin concentrations were slightly lower in AroG(*) cells, and the relative frequencies of the different anthocyanins changed as well.

  18. Phenylalanine and tyrosine levels are rate-limiting factors in production of health promoting metabolites in Vitis vinifera cv. Gamay Red cell suspension

    Directory of Open Access Journals (Sweden)

    Neta eManela


    Full Text Available Environmental stresses such as high light intensity and temperature cause induction of the shikimate pathway, aromatic amino acids (AAA pathways, and of pathways downstream from AAAs. The induction leads to production of specialized metabolites that protect the cells from oxidative damage. The regulation of the diverse AAA derived pathways is still not well understood. To gain insight on that regulation, we increased AAA production in red grape Vitis vinifera cv. Gamay Red cell suspension, without inducing external stress on the cells, and characterized the metabolic effect of this induction. Increased AAA production was achieved by expressing a feedback-insensitive bacterial form of 3-deoxy- D-arabino-heptulosonate 7-phosphate synthase enzyme (AroG* of the shikimate pathway under a constitutive promoter. The presence of AroG* protein led to elevated levels of primary metabolites in the shikimate and AAA pathways including phenylalanine and tyrosine, and to a dramatic increase in phenylpropanoids. The AroG* transformed lines accumulated up to 20 and 150 fold higher levels of resveratrol and dihydroquercetin, respectively. Quercetin, formed from dihydroquercetin, and resveratrol, are health promoting metabolites that are induced due to environmental stresses. Testing the expression level of key genes along the stilbenoids, benzenoids and phenylpropanoid pathways showed that transcription was not affected by AroG*. This suggests that concentrations of AAAs, and of phenylalanine in particular, are rate-limiting in production of these metabolites. In contrast, increased phenylalanine production did not lead to elevated concentrations of anthocyanins, even though they are also phenylpropanoid metabolites. This suggests a control mechanism of this pathway that is independent of AAA concentration. Interestingly, total anthocyanin concentrations were slightly lower in AroG* cells, and the relative frequencies of the different anthocyanins changed as

  19. A novel method to generate and culture human mast cells: Peripheral CD34+ stem cell-derived mast cells (PSCMCs). (United States)

    Schmetzer, Oliver; Valentin, Patricia; Smorodchenko, Anna; Domenis, Rossana; Gri, Giorgia; Siebenhaar, Frank; Metz, Martin; Maurer, Marcus


    The identification and characterization of human mast cell (MC) functions are hindered by the shortage of MC populations suitable for investigation. Here, we present a novel technique for generating large numbers of well differentiated and functional human MCs from peripheral stem cells (=peripheral stem cell-derived MCs, PSCMCs). Innovative and key features of this technique include 1) the use of stem cell concentrates, which are routinely discarded by blood banks, as the source of CD34+ stem cells, 2) cell culture in serum-free medium and 3) the addition of LDL as well as selected cytokines. In contrast to established and published protocols that use CD34+ or CD133+ progenitor cells from full blood, we used a pre-enriched cell population obtained from stem cell concentrates, which yielded up to 10(8) differentiated human MCs per batch after only three weeks of culture starting with 10(6) total CD34+ cells. The total purity on MCs (CD117+, FcεR1+) generated by this method varied between 55 and 90%, of which 4-20% were mature MCs that contain tryptase and chymase and show expression of FcεRI and CD117 in immunohistochemistry. PSCMCs showed robust histamine release in response to stimulation with anti-FcεR1 or IgE/anti-IgE, and increased proliferation and differentiation in response to IL-1β or IFN-γ. Taken together, this new protocol of the generation of large numbers of human MCs provides for an innovative and suitable option to investigate the biology of human MCs.

  20. The enzyme lecithin-cholesterol acyltransferase esterifies cerebrosterol and limits the toxic effect of this oxysterol on SH-SY5Y cells. (United States)

    La Marca, Valeria; Spagnuolo, Maria Stefania; Cigliano, Luisa; Marasco, Daniela; Abrescia, Paolo


    Cholesterol is mostly removed from the CNS by its conversion to cerebrosterol (24(S)-hydroxycholesterol, 24(S)OH-C), which is transported to the circulation for bile formation in liver. A neurotoxic role of this oxysterol was previously demonstrated in cell culture. Here, we provide evidence that the enzyme lecithin-cholesterol acyltransferase, long known to esterify cholesterol, also produces monoesters of 24(S)OH-C. Proteoliposomes containing apolipoprotein A-I or apolipoprotein E were used to stimulate the enzyme activity and entrap the formed esters. Proteoliposomes with apolipoprotein A-I were found to be more active than those with apolipoprotein E in stimulating the production of oxysteryl esters. Cholesterol and 24(S)OH-C were found to compete for enzyme activity. High levels of haptoglobin, as those circulating during the acute inflammatory phase, inhibited 24(S)OH-C esterification. When highly neurotoxic 24(S)OH-C was treated with enzyme and proteoliposomes before incubation with differentiated SH-SY5Y cells, the neuron survival improved. The esters of 24(S)OH-C, embedded into proteoliposomes by the enzyme and isolated from unesterified 24(S)OH-C by gel filtration chromatography, did not enter the neurons in culture. These results suggest that the enzyme, in the presence of the apolipoproteins, converts 24(S)OH-C into esters restricted to the extracellular environment, thus preventing or limiting oxysterol-induced neurotoxic injuries to neurons in culture. 24-hydroxycholesterol (24(S)OH-C) is neurotoxic. The enzyme lecithin-cholesterol acyltransferase (LCAT) synthesizes monoesters of 24(S)OH-C in reaction mixtures with proteoliposomes containing phospholipids and apolipoprotein A-I or apolipoprotein E. The esters, also produced by incubation of cerebrospinal fluid only with tritiated 24(S)OH-C, are embedded into lipoproteins that do not enter neurons in culture. The enzyme activity limits the toxicity of 24-hydroxycholesterol in neuron culture.

  1. Evaluation of limiting factors affecting photovoltaic performance of low-temperature-processed TiO₂ films in dye-sensitized solar cells. (United States)

    Lee, Taek-Yong; Kim, Hui-Seon; Park, Nam-Gyu


    Limiting factors affecting photovoltaic performance of dye-sensitized solar cell employing low-temperature-processed TiO2 films were investigated. TiO2 films were prepared at a low temperature of 200 °C using the normal alcohol-containing binder-free TiO2 paste (LT200). Their photovoltaic performance was compared to a high-temperature (550 °C) annealed TiO2 film prepared using a polymer binder containing TiO2 paste (HT550). Compared to the proportional increase in conversion efficiency with TiO2 film thickness upto 14 μm for HT550, the increase in efficiency was terminated at relatively smaller thickness of about 8 μm for LT200 mainly due to unaugmented photocurrent. From the transient photocurrent-voltage studies, the electron transport rate was found to be almost identical, while charge recombination was one order of magnitude faster for LT200. Consequently, the electron diffusion length was more than 2-3 times shorter for LT200 than for HT550. Electron diffusion length and electron life time obtained from electrochemical impedance analysis were well consistent with those observed from transient measurement. Density of states (DOS) was evaluated to be shallow and narrow in LT200, which was responsible for limiting photovoltaic performance in the low-temperature processed TiO2 film.

  2. Limits on $\

    CERN Document Server

    Perego, D L


    A limit on the tau neutrino mass is obtained using all the $Z^{0} \\to \\tau^{+} \\tau^{-}$ data collected at LEP by the DELPHI detector between 1992 and 1995. In this analysis events in which one of the taus decays into one charged particle, while the second $\\tau$ decays into f{}ive charged pions (1-5 topology) have been used. The neutrino mass is determined from a bidimensional \\fit ~on the invariant mass $m^{*}_{5 \\pi}$ and on the energy $E_{5 \\pi}$ of the f{}ive $\\pi^{\\pm}$ system. The result found is $m_{\

  3. Additional Survival Benefit of Involved-Lesion Radiation Therapy After R-CHOP Chemotherapy in Limited Stage Diffuse Large B-Cell Lymphoma

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Jeanny [Department of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Kim, Il Han, E-mail: [Department of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Cancer Research Institute, Seoul National University College of Medicine, Seoul (Korea, Republic of); Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul (Korea, Republic of); Kim, Byoung Hyuck [Department of Radiation Oncology, Seoul National University College of Medicine, Seoul (Korea, Republic of); Kim, Tae Min; Heo, Dae Seog [Department of Internal Medicine, Seoul National University Hospital, Seoul (Korea, Republic of)


    Purpose: The purpose of this study was to evaluate the role of involved-lesion radiation therapy (ILRT) after rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy in limited stage diffuse large B-cell lymphoma (DLBCL) by comparing outcomes of R-CHOP therapy alone with R-CHOP followed by ILRT. Methods and Materials: We identified 198 patients treated with R-CHOP (median, 6 cycles) for pathologically confirmed DLBCL of limited stage from July 2004 to December 2012. Clinical characteristics of these patients were 33% with stage I and 66.7% with stage II; 79.8% were in the low or low-intermediate risk group; 13.6% had B symptoms; 29.8% had bulky tumors (≥7 cm); and 75.3% underwent ≥6 cycles of R-CHOP therapy. RT was given to 43 patients (21.7%) using ILRT technique, which included the prechemotherapy tumor volume with a median margin of 2 cm (median RT dose: 36 Gy). Results: After a median follow-up of 40 months, 3-year progression-free survival (PFS) and overall survival (OS) were 85.8% and 88.9%, respectively. Multivariate analysis showed ≥6 cycles of R-CHOP (PFS, P=.004; OS, P=.004) and ILRT (PFS, P=.021; OS, P=.014) were favorable prognosticators of PFS and OS. A bulky tumor (P=.027) and response to R-CHOP (P=.012) were also found to be independent factors of OS. In subgroup analysis, the effect of ILRT was prominent in patients with a bulky tumor (PFS, P=.014; OS, P=.030) or an elevated level of serum lactate dehydrogenase (LDH; PFS, P=.004; OS, P=.012). Conclusions: Our results suggest that ILRT after R-CHOP therapy improves PFS and OS in patients with limited stage DLBCL, especially in those with bulky disease or an elevated serum LDH level.

  4. Optimization of the analogue-sensitive Cdc2/Cdk1 mutant by in vivo selection eliminates physiological limitations to its use in cell cycle analysis. (United States)

    Aoi, Yuki; Kawashima, Shigehiro A; Simanis, Viesturs; Yamamoto, Masayuki; Sato, Masamitsu


    Analogue-sensitive (as) mutants of kinases are widely used to selectively inhibit a single kinase with few off-target effects. The analogue-sensitive mutant cdc2-as of fission yeast (Schizosaccharomyces pombe) is a powerful tool to study the cell cycle, but the strain displays meiotic defects, and is sensitive to high and low temperature even in the absence of ATP-analogue inhibitors. This has limited the use of the strain for use in these settings. Here, we used in vivo selection for intragenic suppressor mutations of cdc2-as that restore full function in the absence of ATP-analogues. The cdc2-asM17 underwent meiosis and produced viable spores to a similar degree to the wild-type strain. The suppressor mutation also rescued the sensitivity of the cdc2-as strain to high and low temperature, genotoxins and an anti-microtubule drug. We have used cdc2-asM17 to show that Cdc2 activity is required to maintain the activity of the spindle assembly checkpoint. Furthermore, we also demonstrate that maintenance of the Shugoshin Sgo1 at meiotic centromeres does not require Cdc2 activity, whereas localization of the kinase aurora does. The modified cdc2-asM17 allele can be thus used to analyse many aspects of cell-cycle-related events in fission yeast.

  5. A Gurson-type criterion for porous ductile solids containing arbitrary ellipsoidal voids—I: Limit-analysis of some representative cell (United States)

    Madou, Komlanvi; Leblond, Jean-Baptiste


    Gurson (1977)'s famous model of the behavior of porous ductile solids, initially developed for spherical cavities, was extended by Gologanu et al. (1993, 1994, 1997) to spheroidal, both prolate and oblate voids. The aim of this work is to further extend it to general (non-spheroidal) ellipsoidal cavities, through approximate homogenization of some representative elementary porous cell. As a first step, we perform in the present Part I a limit-analysis of such a cell, namely an ellipsoidal volume made of some rigid-ideal-plastic von Mises material and containing a confocal ellipsoidal void, loaded arbitrarily under conditions of homogeneous boundary strain rate. This analysis provides an estimate of the overall plastic dissipation based on a family of trial incompressible velocity fields recently discovered by Leblond and Gologanu (2008), satisfying conditions of homogeneous strain rate on all ellipsoids confocal with the void and the outer boundary. The asymptotic behavior of the integrand in the expression of the global plastic dissipation is studied both far from and close to the void. The results obtained suggest approximations leading to explicit approximate expressions of the overall dissipation and yield function. These expressions contain parameters the full determination of which will be the object of Part II.

  6. A computational functional genomics based self-limiting self-concentration mechanism of cell specialization as a biological role of jumping genes. (United States)

    Lötsch, Jörn; Ultsch, Alfred


    Specialization is ubiquitous in biological systems and its manifold mechanisms are active research topics. Although clearly adaptive, the way in which specialization of cells is realized remains incompletely understood as it requires the reshaping of a cell's genome to favor particular biological processes in the competition on a cell's functional capacity. Here, a self-specialization mechanism is identified as a possible biological role of jumping genes, in particular LINE-1 retrotransposition. The mechanism is self-limiting and consistent with its evolutionary preservation despite its likely gene-breaking effects. The scenario we studied was the need for a cell to process a longer exposition to an extraordinary situation, for example continuous exposure to the nociceptive input or the intake of addictive drugs. Both situations may evolve toward chronification. The mechanism involves competition within a gene set in which a subset of genes cooperating in particular biological processes. The subset carries a piece of information, consisting of the LINE-1 sequence, about the destruction of their functional competitor genes which are not involved in that process. During gene transcription, an active copy of LINE-1 is co-transcribed. At a certain low probability, a subsequently transcribed and thus actually exposed gene can be rendered nonfunctional by LINE-1 retrotransposition in a relevant gene part. As retrotransposition needs time it is unlikely that LINE-1 retrotranspose into its own carrier gene. This reshapes the cell genome toward self-specializing of those biological processes that are carried out with a high number of LINE-1 containing genes. Self-termination of the mechanism is achieved by allowing LINE-1 to also occasionally jump into the coding region of itself, thus destroying the information about competitor destruction by successively decreasing the number of LINE-1 until the mechanism ceases. Employing a computational functional genomics approach, we

  7. Mediators of Mast Cells in Bullous Pemphigoid and Dermatitis Herpetiformis

    Directory of Open Access Journals (Sweden)

    Agnieszka Zebrowska


    Full Text Available Bullous pemphigoid (BP and dermatitis herpetiformis (DH are skin diseases associated with inflammation. However, few findings exist concerning the role of mast cells in autoimmune blistering disease. Skin biopsies were taken from 27 BP and 14 DH patients, as well as 20 healthy individuals. Immunohistochemistry was used to identify the localization and mast cell expression of TNFα and MMP9 in skin lesions and perilesional skin. The serum concentrations of TNFα, MMP9, chymase, tryptase, PAF, and IL-4 were measured by immunoassay. TNFα and MMP9 expression in the epidermis and in inflammatory influxed cells in the dermis was detected in skin biopsies from patients. Although these mediators were found to be expressed in the perilesional skin of all patients, the level was much lower than that in lesional skin. Increased serum PAF levels were observed in BP patients. Mast cells may play an essential role in activating inflammation, which ultimately contributes to the tissue damage observed in BP and DH. Our findings suggest that differences in the pattern of cytokine expression directly contribute to variations in cellular infiltration in DH and BP.

  8. A rapid method for the differentiation of yeast cells grown under carbon and nitrogen-limited conditions by means of partial least squares discriminant analysis employing infrared micro-spectroscopic data of entire yeast cells (United States)

    Kuligowski, Julia; Quintás, Guillermo; Herwig, Christoph; Lendl, Bernhard


    This paper shows the ease of application and usefulness of mid-IR measurements for the investigation of orthogonal cell states on the example of the analysis of Pichia pastoris cells. A rapid method for the discrimination of entire yeast cells grown under carbon and nitrogen-limited conditions based on the direct acquisition of mid-IR spectra and partial least squares discriminant analysis (PLS-DA) is described. The obtained PLS-DA model was extensively validated employing two different validation strategies: (i) statistical validation employing a method based on permutation testing and (ii) external validation splitting the available data into two independent sub-sets. The Variable Importance in Projection scores of the PLS-DA model provided deeper insight into the differences between the two investigated states. Hence, we demonstrate the feasibility of a method which uses IR spectra from intact cells that may be employed in a second step as an in-line tool in process development and process control along Quality by Design principles. PMID:22967595

  9. Dosimetric rationale and early experience at UFPTI of thoracic proton therapy and chemotherapy in limited-stage small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Colaco, Rovel J.; Huh, Soon; Nichols, Romaine; Morris, Christopher G.; Flampouri, Stella; Li, Zuofeng; Hoppe, Bradford S. [Univ. of Florida Proton Therapy Inst., Jacksonville (United States)], e-mail:; D' Agostino, Harry [Dept. of Thoracic Surgery, Univ. of Florida Coll. of Medicine, Gainesville (United States); Pham, Dat C. [Dept. of Hematology and Medical Oncology, Univ. of Florida Coll. of Medicine, Gainesville (United States); Bajwa, Abubakr A. [Dept. of Medicine, Univ. of Florida Coll. of Medicine, Gainesville (United States)


    Background: Concurrent chemoradiotherapy (CRT) is the standard of care in patients with limited-stage small cell lung cancer (SCLC). Treatment with conventional x-ray therapy (XRT) is associated with high toxicity rates, particularly acute grade 3+ esophagitis and pneumonitis. We present outcomes for the first known series of limited-stage SCLC patients treated with proton therapy and a dosimetric comparison of lung and esophageal doses with intensity-modulated radiation therapy (IMRT). Material and methods: Six patients were treated; five concurrently and one sequentially. Five patients received 60-66 CGE in 30-34 fractions once daily and one patient received 45 CGE in 30 fractions twice daily. All six patients received prophylactic cranial irradiation. Common Terminology Criteria for Adverse Events, v3.0, was used to grade toxicity. IMRT plans were also generated and compared with proton plans. Results: The median follow-up was 12.0 months. The one-year overall and progression-free survival rates were 83% and 66%, respectively. There were no cases of acute grade 3+ esophagitis or acute grade 2+ pneumonitis, and no other acute grade 3+ non-hematological toxicities were seen. One patient with a history of pulmonary fibrosis and atrial fibrillation developed worsening symptoms four months after treatment requiring oxygen. Three patients died; two of progressive disease and one after a fall. The latter patient was disease-free at 36 months after treatment. Another patient recurred and is alive, while two patients remain disease-free at 12 months of follow-up. Proton therapy proved superior to IMRT across all esophageal and lung dose volume points. Conclusion. In this small series of SCLC patients treated with proton therapy with radical intent, treatment was well tolerated with no cases of acute grade 3+ esophagitis or acute grade 2+ pneumonitis. Dosimetric comparison showed better sparing of lung and esophagus with proton therapy. Proton therapy merits further

  10. Plasmonic silicon solar cell comprised of aluminum nanoparticles: Effect of nanoparticles' self-limiting native oxide shell on optical and electrical properties (United States)

    Parashar, Piyush K.; Sharma, R. P.; Komarala, Vamsi K.


    The aluminum nanoparticles' (Al NPs) morphology is optimized initially, for maximum light confinement into a silicon substrate. With self-limiting native oxide shell on the Al NPs after ageing, the maximum photocurrent enhancement (from 26.89 to 29.21 mA/cm2) from a silicon solar cell is observed as compared to the bare cell, in surface plasmon resonance and off-resonance regions due to improved light forward scattering, with no occurrence of Fano resonances. Related to the electrical properties of the plasmonic device, an increase in fill factor (from 56.11 to 62.58) and a decrease in series resistance (from 1.80 Ω to 1.24 Ω) are also observed after the oxide layer formation on Al NPs. The passive partial dielectric oxide layer at the interface helped in electrical passivation by reducing lateral resistance to current flow along the plane of the interface. A finite-element method is also adapted to calculate spatial and angular radiative dipole field distributions for the experimentally optimized Al NPs' size on a silicon substrate, without and with oxide inclusion in NPs for explaining the plasmonic device performance enhancement. With oxide inclusion, Al NPs' dipole field exhibited a large shift towards a silicon due to the modified dielectric environment as compared to without oxide. Bruggeman effective medium theory (for dielectric response) is also used to explain the results with the modification in peak radiative power, spectral field distribution, and spatial and angular radiative dipole field distributions of Al NPs with oxide inclusion in Al.

  11. Incorporating protein transduction domains (PTD) within intracellular proteins associated with the 'stemness' phenotype. Novel use of such recombinant 'fusion' proteins to overcome current limitations of applying autologous adult stem cells in regenerative medicine? (United States)

    Heng, Boon Chin; Cao, Tong


    Adult stem cells originating from post-natal tissues hold tremendous promise in regenerative medicine. Nevertheless, there are several deficiencies of adult stem cells that would limit their application in transplantation therapy, in particular their relative scarcity, restricted multi-potency and limited proliferative capacity in vitro. A possible approach to overcome these limitations would be to genetically modulate adult stem cells to strongly express genes that are closely associated with the 'stemness' phenotype. Overwhelming safety concerns would preclude the direct application of recombinant DNA technology in genetic modulation. Moreover, constitutive expression of 'stemness' genes would prevent adult stem cells from participating in tissue/organ regeneration upon transplantation. A novel alternative would be to incorporate protein transduction domains within intracellular proteins (i.e. transcription factors) that are associated with the 'stemness' phenotype. Such recombinant fusion proteins would then have the ability to translocate across the cell membrane and be internalized within the cytosol, thereby enabling them to exert a gene-modulatory effect on the cell, without any permanent genetic alteration. This would be particularly useful for maintaining the 'stemness' of adult stem cell populations during extensive ex vivo proliferation, to generate adequate cell numbers for transplantation therapy.

  12. Single-cell mass spectrometry reveals the importance of genetic diversity and plasticity for phenotypic variation in nitrogen-limited Chlamydomonas. (United States)

    Krismer, Jasmin; Tamminen, Manu; Fontana, Simone; Zenobi, Renato; Narwani, Anita


    Phenotypic variation is vital for microbial populations to survive environmental perturbations. Both genetic and non-genetic factors contribute to an organism's phenotypic variation and therefore its fitness. To investigate the correlation between genetic diversity and phenotypic variation, we applied our recently developed mass spectrometry method that allows for the simultaneous measurement of more than 25 different lipids and pigments with high throughput in the unicellular microalga Chlamydomonas reinhardtii. We monitored the impact of nitrogen limitation on a genetically diverse wild-type strain CC-1690 and two isoclonal isolates from CC-1690 named ANC3 and ANC5. Measuring molecular composition of thousands of single cells at different time points of the experiment allowed us to capture a dynamic picture of the phenotypic composition and adaptation of the populations over time. Although the genetically diverse population maintained phenotypic variation over the whole time course of the experiment, the isoclonal cultures showed higher synchronicity in their phenotypic response. Furthermore, the genetically diverse population showed equal or greater phenotypic variation over the whole time range in multidimensional trait space compared with isoclonal populations. However, along individual trait axes non-genetic variance was higher in isoclonal populations.The ISME Journal advance online publication, 9 December 2016; doi:10.1038/ismej.2016.167.

  13. Silicon photomultiplier (SPM) detection of low-level bioluminescence for the development of deployable whole-cell biosensors: Possibilities and limitations (United States)

    Li, Huaqing; Lopes, Nicholas; Moser, Scott; Sayler, Gary; Ripp, Steven


    Whole-cell bacterial bioreporters await miniaturized photon counting modules with high sensitivity and robust compatible hardware to fulfill their promise of versatile, on-site biosensor functionality. In this study, we explore the photon counting readout properties of the silicon photomultiplier (SPM) with a thermoelectric cooler and the possibilities of detecting low-level bioluminescent signals. Detection performance was evaluated through a simulated LED light source and the bioluminescence produced by the genetically engineered Pseudomonas fluorescens bacterial bioreporter 5RL. Compared with the conventional photomultiplier tube (PMT), the results revealed that the cooled SPM exhibits a wider linear response to inducible substrate concentrations (salicylate) ranging from 250 to 5000 ppb. Although cooling of the SPM lowered dark count rates and improved the minimum detectable signal, and the application of a digital filter enhanced the signal-to-noise ratio, the detection of very low light signals is still limited and remains a challenge in the design of compact photon counting systems. PMID:22305444

  14. Quantitative proteomic view on secreted, cell surface-associated, and cytoplasmic proteins of the methicillin-resistant human pathogen Staphylococcus aureus under iron-limited conditions. (United States)

    Hempel, Kristina; Herbst, Florian-Alexander; Moche, Martin; Hecker, Michael; Becher, Dörte


    Staphylococcus aureus is capable of colonizing and infecting humans by its arsenal of surface-exposed and secreted proteins. Iron-limited conditions in mammalian body fluids serve as a major environmental signal to bacteria to express virulence determinants. Here we present a comprehensive, gel-free, and GeLC-MS/MS-based quantitative proteome profiling of S. aureus under this infection-relevant situation. (14)N(15)N metabolic labeling and three complementing approaches were combined for relative quantitative analyses of surface-associated proteins. The surface-exposed and secreted proteome profiling approaches comprise trypsin shaving, biotinylation, and precipitation of the supernatant. By analysis of the outer subproteomic and cytoplasmic protein fraction, 1210 proteins could be identified including 221 surface-associated proteins. Thus, access was enabled to 70% of the predicted cell wall-associated proteins, 80% of the predicted sortase substrates, two/thirds of lipoproteins and more than 50% of secreted and cytoplasmic proteins. For iron-deficiency, 158 surface-associated proteins were quantified. Twenty-nine proteins were found in altered amounts showing particularly surface-exposed proteins strongly induced, such as the iron-regulated surface determinant proteins IsdA, IsdB, IsdC and IsdD as well as lipid-anchored iron compound-binding proteins. The work presents a crucial subject for understanding S. aureus pathophysiology by the use of methods that allow quantitative surface proteome profiling.

  15. Effectiveness of cyclooxygenase-2 inhibition in limiting abdominal aortic aneurysm progression in mice correlates with a differentiated smooth muscle cell phenotype. (United States)

    Mukherjee, Kamalika; Gitlin, Jonathan M; Loftin, Charles D


    Abdominal aortic aneurysms (AAAs) are a chronic condition that often progress over years to produce a weakened aorta with increased susceptibility for rupture, and currently, there are no pharmacological treatments available to slow disease progression. AAA development has been characterized by increased expression of cyclooxygenase-2 (COX-2), and inactivation of COX-2 before disease initiation reduces AAA incidence in a mouse model of the disease. The current study determined the effectiveness of COX-2 inhibition on AAA progression when treatment was begun after initiation of the disease. COX-2 inhibitor treatment with celecoxib was initiated after angiotensin II-induced AAA formation in a strain of nonhyperlipidemic mice that we have previously identified as highly susceptible to AAA development. When analyzed at different time points during progression of the disease, celecoxib treatment significantly reduced the incidence and severity of AAAs. The celecoxib treatment also protected the mice from aortic rupture and death. The aneurysmal lesion displayed an altered smooth muscle cell (SMC) phenotype, whereas celecoxib treatment was associated with increased expression of differentiated SMC markers and reduced dedifferentiation marker expression during AAA progression. Maintenance of a differentiated SMC phenotype is associated with the effectiveness of COX-2 inhibition for limiting AAA progression in nonhyperlipidemic mice.

  16. Olfactory cells via nasal biopsy reflect the developing brain in gene expression profiles: utility and limitation of the surrogate tissues in research for brain disorders. (United States)

    Horiuchi, Yasue; Kano, Shin-Ichi; Ishizuka, Koko; Cascella, Nicola G; Ishii, Seiji; Talbot, C Conover; Jaffe, Andrew E; Okano, Hideyuki; Pevsner, Jonathan; Colantuoni, Carlo; Sawa, Akira


    Human olfactory cells obtained by rapid nasal biopsy have been suggested to be a good surrogate system to address brain disease-associated molecular changes. Nonetheless, whether use of this experimental strategy is justified remains unclear. Here we compared expression profiles of olfactory cells systematically with those from the brain tissues and other cells. Principal component analysis indicated that the expression profiles of olfactory cells are very different from those of blood cells, but are closer to those of stem cells, in particular mesenchymal stem cells, that can be differentiated into the cells of the central nervous system.

  17. Mast cells and angiogenesis in primary and recurrent pterygia

    Directory of Open Access Journals (Sweden)

    Fatma Hüsniye DİLEK


    Full Text Available Pterygium is a common benign lesion of limbus but the pathogenesis are not completely understood. Pterygia have a chronic inflammatory cellular infiltrate and a rich vasculature. Mast cells are a heterogeneous group of multifunctional tissue-resident cells. It has been suggested that mast cells and their products may be responsible for the formation of new blood vessels. We investigated the number and phenotype of mast cells and neovascularization in pterygia specimens and compared with those in normal conjunctival specimensPterygia tissues were obtained during excisional surgery from 32 eyes of 32 consecutive patients. Seventeen of all cases were recurrent pterygia. Superior bulbar conjunctival tissue from the same eye was also sampled as control tissues. The tissue sections were stained with routine hematoxyline-eosin and toluidine blue stain for mast cells. For immunohistochemical studies anti-factor VIII-related antigen, monoclonal anti human mast cell tryptase and chymase were used as an endothelial and mast cell marker.The mean number of mast cells in pterygia was significantly higher than that in the normal conjunctival tissue and microvessel counts was significantly higher than the counts of the controls in both primary and recurrent pterygia. There was no correlation between microvessel numbers and mast cell numbers. There was no phenotypic difference between the mast cells in the ptergyia and those in the normal conjunctival tissues.This study confirms that mast cells are prominent in pterygia and our results suggest that mast cells and angiogenesis are independent factors in the genesis and progress of ptergyium.

  18. Increased Biological Effective Dose of Radiation Correlates with Prolonged Survival of Patients with Limited-Stage Small Cell Lung Cancer: A Systematic Review.

    Directory of Open Access Journals (Sweden)

    Lucheng Zhu

    Full Text Available Thoracic radiotherapy (TRT is a critical component of the treatment of limited-stage small cell lung cancer (LS-SCLC. However, the optimal radiation dose/fractionation remains elusive. This study reviewed current evidence and explored the dose-response relationship in patients with LS-SCLC who were treated with radiochemotherapy.A quantitative analysis was performed through a systematic search of PubMed, Web of Science, and the Cochrane Library. The correlations between the biological effective dose (BED and median overall survival (mOS, median progression-free survival (mPFS, 1-, 3-, and 5-year overall survival (OS as well as local relapse (LR were evaluated.In all, 2389 patients in 19 trials were included in this study. Among these 19 trials, seven were conducted in Europe, eight were conducted in Asia and four were conducted in the United States. The 19 trials that were included consisted of 29 arms with 24 concurrent and 5 sequential TRT arms. For all included studies, the results showed that a higher BED prolonged the mOS (R2 = 0.198, p<0.001 and the mPFS (R2 = 0.045, p<0.001. The results also showed that increased BED improved the 1-, 3-, and 5-year OS. A 10-Gy increment added a 6.3%, a 5.1% and a 3.7% benefit for the 1-, 3-, and 5-year OS, respectively. Additionally, BED was negatively correlated with LR (R2 = 0.09, p<0.001. A subgroup analysis of concurrent TRT showed that a high BED prolonged the mOS (p<0.001 and the mPFS (p<0.001, improved the 1-, 3-, and 5-year OS (p<0.001 and decreased the rate of LR (p<0.001.This study showed that an increased BED was associated with improved OS, PFS and decreased LR in patients with LS-SCLC who were treated with combined chemoradiotherapy, which indicates that the strategy of radiation dose escalation over a limited time frame is worth exploring in a prospective clinical trial.

  19. Stimulated mast cells promote maturation of myocardial microvascular endothelial cell neovessels by modulating the angiopoietin-Tie-2 signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Z.H. [Division of Cardiology, Shanghai Sixth People' s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China, Division of Cardiology, Shanghai Sixth People’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai (China); Yancheng People' s First Hospital, Division of Cardiology, Yancheng, Jiangsu, China, Division of Cardiology, Yancheng People’s First Hospital, Yancheng, Jiangsu (China); Zhu, W.; Tao, J.P.; Zhang, Q.Y.; Wei, M. [Division of Cardiology, Shanghai Sixth People' s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China, Division of Cardiology, Shanghai Sixth People’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai (China)


    Angiopoietin (Ang)-1 and Ang-2 interact in angiogenesis to activate the Tie-2 receptor, which may be involved in new vessel maturation and regression. Mast cells (MCs) are also involved in formation of new blood vessels and angiogenesis. The present study was designed to test whether MCs can mediate angiogenesis in myocardial microvascular endothelial cells (MMVECs). Using a rat MMVEC and MC co-culture system, we observed that Ang-1 protein levels were very low even though its mRNA levels were increased by MCs. Interestingly, MCs were able to enhance migration, proliferation, and capillary-like tube formation, which were associated with suppressed Ang-2 protein expression, but not Tie-2 expression levels. These MCs induced effects that could be reversed by either tryptase inhibitor [N-tosyl-L-lysine chloromethyl ketone (TLCK)] or chymase inhibitor (N-tosyl-L-phenylalanyl chloromethyl ketone), with TLCK showing greater effects. In conclusion, our data indicated that MCs can interrupt neovessel maturation via suppression of the Ang-2/Tie-2 signaling pathway.

  20. A TIR-NBS protein encoded by Arabidopsis Chilling Sensitive 1 (CHS1) limits chloroplast damage and cell death at low temperature. (United States)

    Zbierzak, Anna Maria; Porfirova, Svetlana; Griebel, Thomas; Melzer, Michael; Parker, Jane E; Dörmann, Peter


    Survival of plants at low temperature depends on mechanisms for limiting physiological damage and maintaining growth. We mapped the chs1-1 (chilling sensitive1-1) mutation in Arabidopsis accession Columbia to the TIR-NBS gene At1g17610. In chs1-1, a single amino acid exchange at the CHS1 N-terminus close to the conserved TIR domain creates a stable mutant protein that fails to protect leaves against chilling stress. The sequence of another TIR-NBS gene (At5g40090) named CHL1 (CHS1-like 1) is related to that of CHS1. Over-expression of CHS1 or CHL1 alleviates chilling damage and enhances plant growth at moderate (24°C) and chilling (13°C) temperatures, suggesting a role for both proteins in growth homeostasis. chs1-1 mutants show induced salicylic acid production and defense gene expression at 13°C, indicative of autoimmunity. Genetic analysis of chs1-1 in combination with defense pathway mutants shows that chs1-1 chilling sensitivity requires the TIR-NBS-LRR and basal resistance regulators encoded by EDS1 and PAD4 but not salicylic acid. By following the timing of metabolic, physiological and chloroplast ultrastructural changes in chs1-1 leaves during chilling, we have established that alterations in photosynthetic complexes and thylakoid membrane integrity precede leaf cell death measured by ion leakage. At 24°C, the chs1-1 mutant appears normal but produces a massive necrotic response to virulent Pseudomonas syringae pv. tomato infection, although this does not affect bacterial proliferation. Our results suggest that CHS1 acts at an intersection between temperature sensing and biotic stress pathway activation to maintain plant performance over a range of conditions.

  1. Early treatment volume reduction rate as a prognostic factor in patients treated with chemoradiotherapy for limited stage small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Joo Hwan; Lee, Jeong Shin; Lee, Chang Geol; Cho, Jae Ho [Dept. of Radiation Oncology, Yonsei Cancer Center, Yonsei University College of Medicine, Seoul (Korea, Republic of); Choi, Jin Hyun; Kim, Jun Won [Dept. of Radiation Oncology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)


    To investigate the relationship between early treatment response to definitive chemoradiotherapy (CRT) and survival outcome in patients with limited stage small cell lung cancer (LS-SCLC). We retrospectively reviewed 47 patients with LS-SCLC who received definitive CRT between January 2009 and December 2012. Patients were treated with systemic chemotherapy regimen of etoposide/carboplatin (n = 15) or etoposide/cisplatin (n = 32) and concurrent thoracic radiotherapy at a median dose of 54 Gy (range, 46 to 64 Gy). Early treatment volume reduction rate (ETVRR) was defined as the percentage change in gross tumor volume between diagnostic computed tomography (CT) and simulation CT for adaptive RT planning and was used as a parameter for early treatment response. The median dose at adaptive RT planning was 36 Gy (range, 30 to 43 Gy), and adaptive CT was performed in 30 patients (63.8%). With a median follow-up of 27.7 months (range, 5.9 to 75.8 months), the 2-year locoregional progression-free survival (LRPFS) and overall survival (OS) rates were 74.2% and 56.5%, respectively. The mean diagnostic and adaptive gross tumor volumes were 117.9 mL (range, 5.9 to 447 mL) and 36.8 mL (range, 0.3 to 230.6 mL), respectively. The median ETVRR was 71.4% (range, 30 to 97.6%) and the ETVRR >45% group showed significantly better OS (p < 0.0001) and LRPFS (p = 0.009) than the other group. ETVRR as a parameter for early treatment response may be a useful prognostic factor to predict treatment outcome in LS-SCLC patients treated with CRT.

  2. The yeast three-hybrid system as an experimental platform to identify proteins interacting with small signaling molecules in plant cells: Potential and limitations

    Directory of Open Access Journals (Sweden)

    Stéphanie eCottier


    Full Text Available Chemical genetics is a powerful scientific strategy that utilizes small bioactive molecules as experimental tools to unravel biological processes. Bioactive compounds occurring in nature represent an enormous diversity of structures that can be used to dissect functions of biological systems. Once the bioactivity of a natural or synthetic compound has been critically evaluated the challenge remains to identify its molecular target and mode of action, which usually is a time consuming and labor-intensive process. To facilitate this task, we decided to implement the yeast three-hybrid (Y3H technology as a general experimental platform to scan the whole Arabidopsis proteome for targets of small signaling molecules. The Y3H technology is based on the yeast two-hybrid system and allows direct cloning of proteins that interact in vivo with a synthetic hybrid ligand, which comprises the biologically active molecule of interest covalently linked to methotrexate (Mtx. In yeast nucleus the hybrid ligand connects two fusion proteins: the Mtx part binding to dihydrofolate reductase fused to a DNA binding domain (encoded in the yeast strain, and the bioactive molecule part binding to its potential protein target fused to a DNA activating domain (encoded on a cDNA expression vector. During cDNA library screening, the formation of this ternary, transcriptional activator complex leads to reporter gene activation in yeast cells, and thereby allows selection of the putative targets of small bioactive molecules of interest. Here we present the strategy and experimental details for construction and application of a Y3H platform, including chemical synthesis of different hybrid ligands, construction of suitable cDNA libraries, the choice of yeast strains, and appropriate screening conditions. Based on the results obtained and the current literature we discussed the perspectives and limitations of the Y3H approach for identifying targets of small bioactive molecules.

  3. Cambial activity and xylem cell development in Pinus cembra and Pinus sylvestris at their climatic limits in the Eastern Alps in 2007. (United States)

    Swidrak, Irene; Gruber, Andreas; Oberhuber, Walter


    It has been frequently stressed that at distributional boundaries, like at the Alpine timberline and within dry inner Alpine environments, tree growth will be affected first by changing climate conditions. Climate in 2007 was characterized by the occurrence of exceptionally mild temperatures in spring (3.4 and 2.7 °C above long-term mean (LTM) at timberline and the valley sites, respectively) with an almost continuous drought period recorded in April and slightly warmer than average temperatures throughout summer (1.3 °C above LTM at both sites). We compared temporal dynamics of cambial activity and xylem cell development in Pinus cembra at the Alpine timberline (1950 m a.s.l.) and Pinus sylvestris at a xeric inner Alpine site (750 m a.s.l.) by repeated cellular analyses of micro-cores (n = 5 trees/site). While onset of wood formation in P. sylvestris and P. cembra differed by about two weeks (12 and 27 April, respectively), maximum daily growth rates peaked on 6 May at the valley site and on 23 June at timberline. At both sites maximum tracheid production was reached prior to occurrence of more favourable climatic conditions during summer, i.e. an increase in precipitation and temperature. Xylem formation ended on 31 August and 28 October at the xeric site and at timberline, respectively. This study demonstrates the plasticity of tree-ring formation along an altitudinal transect in response to water availability and temperature. Whether early achievement of maximum growth rates is an adaptation to cope with extreme environmental conditions prevailing at limits of tree growth needs to be analysed more closely by taking belowground carbon allocation into account.

  4. Limitations to the development of recombinant human embryonic kidney 293E cells using glutamine synthetase-mediated gene amplification: Methionine sulfoximine resistance. (United States)

    Yu, Da Young; Noh, Soo Min; Lee, Gyun Min


    To investigate the feasibility of glutamine synthetase (GS)-mediated gene amplification in HEK293 cells for the high-level stable production of therapeutic proteins, HEK293E cells were transfected by the GS expression vector containing antibody genes and were selected at various methionine sulfoximine (MSX) concentrations in 96-well plates. For a comparison, CHOK1 cells were transfected by the same GS expression vector and selected at various MSX concentrations. Unlike CHOK1 cells, HEK293E cells producing high levels of antibodies were not selected at all. For HEK293E cells, the number of wells with the cell pool did not decrease with an increase in the concentration of MSX up to 500μM MSX. A q-RT-PCR analysis confirmed that the antibody genes in the HEK293E cells, unlike the CHOK1 cells, were not amplified after increasing the MSX concentration. It was found that the GS activity in HEK293E cells was much higher than that in CHOK1 cells (P<0.05). In a glutamine-free medium, the GS activity of HEK293E cells was approximately 4.8 times higher than that in CHOK1 cells. Accordingly, it is inferred that high GS activity of HEK293E cells results in elevated resistance to MSX and therefore hampers GS-mediated gene amplification by MSX. Thus, in order to apply the GS-mediated gene amplification system to HEK293 cells, the endogenous GS expression level in HEK293 cells needs to be minimized by knock-out or down-regulation methods.

  5. Neonatal human retinal pigment epithelial cells secrete limited trophic factors in vitro and in vivo following striatal implantation in parkinsonian rats

    DEFF Research Database (Denmark)

    Russ, Kaspar; Flores, Joseph; Brudek, Tomasz


    Human retinal pigment epithelial (hRPE) cell implants into the striatum have been investigated as a potential cell-based treatment for Parkinson's disease in a Phase II clinical trial that recently failed. We hypothesize that the trophic factor potential of the hRPE cells could potentially influe...

  6. Human cyclin T1 expression ameliorates a T-cell-specific transcriptional limitation for HIV in transgenic rats, but is not sufficient for a spreading infection of prototypic R5 HIV-1 strains ex vivo

    Directory of Open Access Journals (Sweden)

    Littman Dan R


    Full Text Available Abstract Background Cells derived from native rodents have limits at distinct steps of HIV replication. Rat primary CD4 T-cells, but not macrophages, display a profound transcriptional deficit that is ameliorated by transient trans-complementation with the human Tat-interacting protein Cyclin T1 (hCycT1. Results Here, we generated transgenic rats that selectively express hCycT1 in CD4 T-cells and macrophages. hCycT1 expression in rat T-cells boosted early HIV gene expression to levels approaching those in infected primary human T-cells. hCycT1 expression was necessary, but not sufficient, to enhance HIV transcription in T-cells from individual transgenic animals, indicating that endogenous cellular factors are critical co-regulators of HIV gene expression in rats. T-cells from hCD4/hCCR5/hCycT1-transgenic rats did not support productive infection of prototypic wild-type R5 HIV-1 strains ex vivo, suggesting one or more significant limitation in the late phase of the replication cycle in this primary rodent cell type. Remarkably, we identify a replication-competent HIV-1 GFP reporter strain (R7/3 YU-2 Env that displays characteristics of a spreading, primarily cell-to-cell-mediated infection in primary T-cells from hCD4/hCCR5-transgenic rats. Moreover, the replication of this recombinant HIV-1 strain was significantly enhanced by hCycT1 transgenesis. The viral determinants of this so far unique replicative ability are currently unknown. Conclusion Thus, hCycT1 expression is beneficial to de novo HIV infection in a transgenic rat model, but additional genetic manipulations of the host or virus are required to achieve full permissivity.

  7. Molecular and stimulus-response profiles illustrate heterogeneity between peripheral and cord blood-derived human mast cells

    DEFF Research Database (Denmark)

    Jensen, Bettina M; Frandsen, Pernille M; Raaby, Ellen M


    Different protocols exist for in vitro development of HuMCs from hematopoietic stem cells, which results in distinct mast cells regarding molecular markers and activation patterns. Here, we introduce a SR profile using immunological, neurogenic, and pharmacological stimuli to characterize cellular...... functionality. Mast cells were obtained from three culture protocols using two types of PBdMCs (CD34(+) PBdMC or CD133(+) PBdMC) and one type of CBdMC (CD133(+) CBdMC). We analyzed resting cells for specific mast cell markers at protein and mRNA levels, thereby creating a molecular profile. To characterize...... the SR profile, we stimulated cells with anti-IgE, C3a, C5a, Substance P, or Compound 48/80 and measured the release of histamine and cytokines (IL-10, IL-13, GM-CSF, TNF-α). Molecular profiling revealed that CD133(+) CBdMC expressed less chymase, FcεRIα, and CD203c but more CD117 compared with CD34...

  8. Tetraploid cells produced by absence of substrate adhesion during cytokinesis are limited in their proliferation and enter senescence after DNA replication. (United States)

    De Santis Puzzonia, Marco; Gonzalez, Laetitia; Ascenzi, Sonia; Cundari, Enrico; Degrassi, Francesca


    Tetraploidy has been proposed as an intermediate state in neoplastic transformation due to the intrinsic chromosome instability of tetraploid cells. Despite the identification of p53 as a major factor in growth arrest of tetraploid cells, it is still unclear whether the p53-dependent mechanism for proliferation restriction is intrinsic to the tetraploid status or dependent on the origin of tetraploidy. Substrate adherence is fundamental for cytokinesis completion in adherent untransformed cells. Here we show that untransformed fibroblast cells undergoing mitosis in suspension produce binucleated tetraploid cells due to defective cleavage furrow constriction that leads to incomplete cell abscission. Binucleated cells obtained after loss of substrate adhesion maintain an inactive p53 status and are able to progress into G1 and S phase. However, binucleated cells arrest in G2, accumulate p53 and are not able to enter mitosis as no tetraploid metaphases were recorded after one cell cycle time. In contrast, tetraploid metaphases were found following pharmacological inhibition of Chk1 kinase, suggesting the involvement of the ATR/Chk1 pathway in the G2 arrest of binucleated cells. Interestingly, after persistence in the G2 phase of the cell cycle, a large fraction of binucleated cells become senescent. These findings identify a new pathway of proliferation restriction for tetraploid untransformed cells that seems to be specific for loss of adhesion-dependent cytokinesis failure. This involves Chk1 and p53 activation during G2. Inhibition of growth and entrance into senescence after cytokinesis in suspension may represent an important mechanism to control tumor growth. In fact, anchorage independent growth is a hallmark of cancer and it has been demonstrated that binucleated transformed cells can enter a cycle of anchorage independent growth.

  9. Behind the 29-percent limit. Solar researcher Martin Green presents ideas for inexpensive high-efficiency solar cells; Hinter der 29-Prozent-Grenze. Solarforscher Martin Green praesentiert Ideen fuer preiswerte Hocheffizienzsolarzellen

    Energy Technology Data Exchange (ETDEWEB)

    Kreutzmann, Anne


    Named after two physicists the Shockley-Queisser limit of 29 percent for today standard silicon solar cells is not reached in mass production. But the closer the industry comes to this physical limit, the more expensive is it to reach the final percentage points. A study by Martin Green, one of the world's leading researchers, and his team shows ways based on cheaper silicon solar cells, how the 29 percent limit can be overcome. [German] Die nach zwei Physikern benannte Shockley-Queisser-Grenze fuer heute uebliche Solarzellen aus Silizium von 29 Prozent ist in der Massenproduktion noch nicht erreicht. Aber je naeher die Industrie dieser physikalischen Grenze kommt, desto teurer wird es, die letzten Prozentpunkte zu schaffen. Eine Untersuchung von Martin Green, einem der weltweit fuehrenden Forscher, und seinem Team zeigt Wege auf, wie auf Grundlage billiger Siliziumsolarzellen die 29-Prozent-Grenze ueberwunden werden kann.

  10. Phase 2 Study of Accelerated Hypofractionated Thoracic Radiation Therapy and Concurrent Chemotherapy in Patients With Limited-Stage Small-Cell Lung Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Bing [Department of Radiation Oncology, Shanghai Cancer Center, Fudan University, Shanghai (China); Department of Radiation Oncology, Hangzhou Cancer Hospital, Hangzhou (China); Hong, Ling-Zhi [Department of Oncology, Nanjing First Hospital, Nanjing Medical University, Nanjing (China); Cai, Xu-Wei; Zhu, Zheng-Fei; Liu, Qi; Zhao, Kuai-Le; Fan, Min; Mao, Jing-Fang; Yang, Huan-Jun; Wu, Kai-Liang [Department of Radiation Oncology, Shanghai Cancer Center, Fudan University, Shanghai (China); Fu, Xiao-Long, E-mail: [Department of Radiation Oncology, Shanghai Chest Hospital, Shanghai Jiao Tong University, Shanghai (China)


    Purpose: To prospectively investigate the efficacy and toxicity of accelerated hypofractionated thoracic radiation therapy (HypoTRT) combined with concurrent chemotherapy in the treatment of limited-stage small-cell lung cancer (LS-SCLC), with the hypothesis that both high radiation dose and short radiation time are important in this setting. Methods and Materials: Patients with previously untreated LS-SCLC, Eastern Cooperative Oncology Group performance status of 0 to 2, and adequate organ function were eligible. HypoTRT of 55 Gy at 2.5 Gy per fraction over 30 days was given on the first day of the second or third cycle of chemotherapy. An etoposide/cisplatin regimen was given to 4 to 6 cycles. Patients who had a good response to initial treatment were offered prophylactic cranial irradiation. The primary endpoint was the 2-year progression-free survival rate. Results: Fifty-nine patients were enrolled from July 2007 through February 2012 (median age, 58 years; 86% male). The 2-year progression-free survival rate was 49.0% (95% confidence interval [CI] 35.3%-62.7%). Median survival time was 28.5 months (95% CI 9.0-48.0 months); the 2-year overall survival rate was 58.2% (95% CI 44.5%-71.9%). The 2-year local control rate was 76.4% (95% CI 63.7%-89.1%). The severe hematologic toxicities (grade 3 or 4) were leukopenia (32%), neutropenia (25%), and thrombocytopenia (15%). Acute esophagitis and pneumonitis of grade ≥3 occurred in 25% and 10% of the patients, respectively. Thirty-eight patients (64%) received prophylactic cranial irradiation. Conclusion: Our study showed that HypoTRT of 55 Gy at 2.5 Gy per fraction daily concurrently with etoposide/cisplatin chemotherapy has favorable survival and acceptable toxicity. This radiation schedule deserves further investigation in LS-SCLC.

  11. Central domain of IL-33 is cleaved by mast cell proteases for potent activation of group-2 innate lymphoid cells. (United States)

    Lefrançais, Emma; Duval, Anais; Mirey, Emilie; Roga, Stéphane; Espinosa, Eric; Cayrol, Corinne; Girard, Jean-Philippe


    Interleukin-33 (IL-33) is an alarmin cytokine from the IL-1 family. IL-33 activates many immune cell types expressing the interleukin 1 receptor-like 1 (IL1RL1) receptor ST2, including group-2 innate lymphoid cells (ILC2s, natural helper cells, nuocytes), the major producers of IL-5 and IL-13 during type-2 innate immune responses and allergic airway inflammation. IL-33 is likely to play a critical role in asthma because the IL33 and ST2/IL1RL1 genes have been reproducibly identified as major susceptibility loci in large-scale genome-wide association studies. A better understanding of the mechanisms regulating IL-33 activity is thus urgently needed. Here, we investigated the role of mast cells, critical effector cells in allergic disorders, known to interact with ILC2s in vivo. We found that serine proteases secreted by activated mast cells (chymase and tryptase) generate mature forms of IL-33 with potent activity on ILC2s. The major forms produced by mast cell proteases, IL-33(95-270), IL-33(107-270), and IL-33(109-270), were 30-fold more potent than full-length human IL-33(1-270) for activation of ILC2s ex vivo. They induced a strong expansion of ILC2s and eosinophils in vivo, associated with elevated concentrations of IL-5 and IL-13. Murine IL-33 is also cleaved by mast cell tryptase, and a tryptase inhibitor reduced IL-33-dependent allergic airway inflammation in vivo. Our study identifies the central cleavage/activation domain of IL-33 (amino acids 66-111) as an important functional domain of the protein and suggests that interference with IL-33 cleavage and activation by mast cell and other inflammatory proteases could be useful to reduce IL-33-mediated responses in allergic asthma and other inflammatory diseases.

  12. Adult Human Pancreatic Islet Beta-Cells Display Limited Turnover and Long Lifespan as Determined by In-Vivo Thymidine Analog Incorporation and Radiocarbon Dating

    Energy Technology Data Exchange (ETDEWEB)

    Perl, S; Kushner, J A; Buchholz, B A; Meeker, A K; Stein, G M; Hsieh, M; Kirby, M; Pechhold, S; Liu, E H; Harlan, D M; Tisdale, J F


    Diabetes mellitus results from an absolute or relative deficiency of insulin producing pancreatic beta-cells. The adult human beta-cell's turnover rate remains unknown. We employed novel techniques to examine adult human islet beta-cell turnover and longevity in vivo. Subjects enrolled in NIH clinical trials received thymidine analogues [iododeoxyuridine (IdU) or bromodeoxyuridine (BrdU)] 8-days to 4-years prior to death. Archival autopsy samples from ten patients (aged 17-74 years) were employed to assess beta-cell turnover by scoring nuclear analog labeling within insulin staining cells. Human adult beta-cell longevity was determined by estimating the cells genomic DNA integration of atmospheric carbon-14 ({sup 14}C). DNA was purified from pancreatic islets isolated from cadaveric donors; whole islet prep DNA was obtained from a 15 year old donor, and purified beta-cell DNA was obtained from two donors (age 48 and 80 years). {sup 14}C levels were then determined using accelerator mass spectrometry (AMS). Cellular 'birth date' was determined by comparing the subject's DNA {sup 14}C content relative to a well-established {sup 14}C atmospheric prevalence curve. In the two subjects less than age 20 years, 1-2% of the beta-cell nuclei co-stained for BrdU/IdU. No beta-cell nuclei co-stained in the eight patients more than 30 years old. Consistent with the BrdU/IdU turnover data, beta-cell DNA {sup 14}C content indicated the cells 'birth date' occurred within the subject's first 30 years of life. Under typical circumstances, adult human beta-cells and their cellular precursors are established by young adulthood.

  13. Establishment of a Conditionally Immortalized Wilms Tumor Cell Line with a Homozygous WT1 Deletion within a Heterozygous 11p13 Deletion and UPD Limited to 11p15.

    Directory of Open Access Journals (Sweden)

    Artur Brandt

    Full Text Available We describe a stromal predominant Wilms tumor with focal anaplasia and a complex, tumor specific chromosome 11 aberration: a homozygous deletion of the entire WT1 gene within a heterozygous 11p13 deletion and an additional region of uniparental disomy (UPD limited to 11p15.5-p15.2 including the IGF2 gene. The tumor carried a heterozygous p.T41A mutation in CTNNB1. Cells established from the tumor carried the same chromosome 11 aberration, but a different, homozygous p.S45Δ CTNNB1 mutation. Uniparental disomy (UPD 3p21.3pter lead to the homozygous CTNNB1 mutation. The tumor cell line was immortalized using the catalytic subunit of human telomerase (hTERT in conjunction with a novel thermolabile mutant (U19dl89-97tsA58 of SV40 large T antigen (LT. This cell line is cytogenetically stable and can be grown indefinitely representing a valuable tool to study the effect of a complete lack of WT1 in tumor cells. The origin/fate of Wilms tumors with WT1 mutations is currently poorly defined. Here we studied the expression of several genes expressed in early kidney development, e.g. FOXD1, PAX3, SIX1, OSR1, OSR2 and MEIS1 and show that these are expressed at similar levels in the parental and the immortalized Wilms10 cells. In addition the limited potential for muscle/ osteogenic/ adipogenic differentiation similar to all other WT1 mutant cell lines is also observed in the Wilms10 tumor cell line and this is retained in the immortalized cells. In summary these Wilms10 cells are a valuable model system for functional studies of WT1 mutant cells.

  14. Autoantibodies against G-Protein-Coupled Receptors Modulate Heart Mast Cells

    Institute of Scientific and Technical Information of China (English)

    Ludmila Okruhlicova; Rosemarie Morwinski; Wolfgang Schulze; Sabine Bartel; Peter Weismann; Narcisa Tribulova; Gerd Wallukat


    Mast cells are believed to be involved in myocardial tissue remodelling under pathophysiological conditions. We examined the effects of autoantibodies against G-protein-coupled receptors in sera of patients with heart diseases on myocardial mast cells in the cultured neonatal Sprague-Dawley rat heart cells. Cells collected at day 3 and 10 of the culture were preincubated with autoantibodies against α1-adrenoceptor and angiotensin Ⅱ AT1-receptor,agonist phenylephrine and angiotensin Ⅱ, and control IgG. The pretreated cultured cells were stained for selected mast cell markers tryptase, chymase and TNF-α. The cultured cells were also processed for observation with electron microscopy. The autoantibodies-treatment of the 3-day cultured cells caused both increased intensity of immunofluorescence (p<0.05) and their enlarged diameters of the mast cells when compared to age-matched ones.In contrast, the fluorescence of preincubated 10-day-old mast cells was decreased compared with controls (p<0.01).In control samples, the fluorescence of 10-day-old mast cells was significantly higher than that of 3-day-old ones (p<0.001). Results of electron microscopy examination demonstrated there was an increased granulation of treated 3-day-old mast cells, while a degranulation of mast cells at day 10 of application. The results suggest the modulation effect of the autoantibodies against G-protein-coupled receptors on mast cells, indicating a potential functional link between the autoantibodies against G-protein-coupled receptors and the mast cells in progression of heart disease.

  15. Adiponectin Suppresses T Helper 17 Cell Differentiation and Limits Autoimmune CNS Inflammation via the SIRT1/PPARγ/RORγt Pathway. (United States)

    Zhang, Kai; Guo, Yawei; Ge, Zhenzhen; Zhang, Zhihui; Da, Yurong; Li, Wen; Zhang, Zimu; Xue, Zhenyi; Li, Yan; Ren, Yinghui; Jia, Long; Chan, Koon-Ho; Yang, Fengrui; Yan, Jun; Yao, Zhi; Xu, Aimin; Zhang, Rongxin


    T helper 17 (Th17) cells are vital components of the adaptive immune system involved in the pathogenesis of most autoimmune and inflammatory syndromes, and adiponectin(ADN) is correlated with inflammatory diseases such as multiple sclerosis (MS) and type II diabetes. However, the regulatory effects of adiponectin on pathogenic Th17 cell and Th17-mediated autoimmune central nervous system (CNS) inflammation are not fully understood. In this study, we demonstrated that ADN could inhibit Th1 and Th17 but not Th2 cells differentiation in vitro. In the in vivo study, we demonstrated that ADN deficiency promoted CNS inflammation and demyelination and exacerbated experimental autoimmune encephalomyelitis (EAE), an animal model of human MS. Furthermore, ADN deficiency increased the Th1 and Th17 cell cytokines of both the peripheral immune system and CNS in mice suffering from EAE. It is worth mentioning that ADN deficiency predominantly promoted the antigen-specific Th17 cells response in autoimmune encephalomyelitis. In addition, in vitro and in vivo, ADN upregulated sirtuin 1 (SIRT1) and peroxisome proliferator-activated receptor γ (PPARγ) and inhibited retinoid-related orphan receptor-γt (RORγt); the key transcription factor during Th17 cell differentiation. These results systematically uncovered the role and mechanism of adiponectin on pathogenic Th17 cells and suggested that adiponectin could inhibit Th17 cell-mediated autoimmune CNS inflammation.

  16. The cotyledon cell wall of the common bean (phaseolus vulgaris) resists digestion in the upper intestine and thus may limit iron bioavailability (United States)

    Strategies that enhance the Fe bioavailability from the bean are of keen interest to nutritionists, bean breeders and growers. In beans, the cotyledon contains 75-80% of the total seed Fe, most of which appears to be located within the cotyledon cell. The cotyledon cell wall is known to be resistan...

  17. Interferon Regulator Factor 8 (IRF8 Limits Ocular Pathology during HSV-1 Infection by Restraining the Activation and Expansion of CD8+ T Cells.

    Directory of Open Access Journals (Sweden)

    Lin Sun

    Full Text Available Interferon Regulatory Factor-8 (IRF8 is constitutively expressed in monocytes and B cell lineages and plays important roles in immunity to pathogens and cancer. Although IRF8 expression is induced in activated T cells, the functional relevance of IRF8 in T cell-mediated immunity is not well understood. In this study, we used mice with targeted deletion of Irf8 in T-cells (IRF8KO to investigate the role of IRF8 in T cell-mediated responses during herpes simplex virus 1 (HSV-1 infection of the eye. In contrast to wild type mice, HSV-1-infected IRF8KO mice mounted a more robust anti-HSV-1 immune response, which included marked expansion of HSV-1-specific CD8+ T cells, increased infiltration of inflammatory cells into the cornea and trigeminal ganglia (TG and enhanced elimination of virus within the trigeminal ganglion. However, the consequence of the enhanced immunological response was the development of ocular inflammation, limbitis, and neutrophilic infiltration into the cornea of HSV-1-infected IRF8KO mice. Surprisingly, we observed a marked increase in virus-specific memory precursor effector cells (MPEC in IRF8KO mice, suggesting that IRF8 might play a role in regulating the differentiation of effector CD8+ T cells to the memory phenotype. Together, our data suggest that IRF8 might play a role in restraining excess lymphocyte proliferation. Thus, modulating IRF8 levels in T cells can be exploited therapeutically to prevent immune-mediated ocular pathology during autoimmune and infectious diseases of the eye.

  18. JA, a new type of polyunsaturated fatty acid isolated from Juglans mandshurica Maxim, limits the survival and induces apoptosis of heptocarcinoma cells. (United States)

    Gao, Xiu-Li; Lin, Hua; Zhao, Wei; Hou, Ya-Qin; Bao, Yong-Li; Song, Zhen-Bo; Sun, Lu-Guo; Tian, Shang-Yi; Liu, Biao; Li, Yu-Xin


    Juglans mandshurica Maxim (Juglandaceae) is a famous folk medicine for cancer treatment and some natural compounds isolated from it have been studied extensively. Previously we isolated a type of ω-9 polyunsaturated fatty acid (JA) from the bark of J. mandshurica, however little is known about its activity and the underlying mechanisms. In this study, we studied anti-tumor activity of JA on several human cancer cell lines. Results showed that JA is cytotoxic to HepG2, MDA-MB-231, SGC-7901, A549 and Huh7 cells at a concentration exerting minimal toxic effects on L02 cells. The selective toxicity of JA was better than other classical anti-cancer drugs. Further investigation indicated that JA could induce cell apoptosis, characterized by chromatin condensation, DNA fragmentation and activation of the apoptosis-associated proteins such as Caspase-3 and PARP-1. Moreover, we investigated the cellular apoptosis pathway involved in the apoptosis process in HepG2 cells. We found that proteins involved in mitochondrion (cleaved-Caspase-9, Apaf-1, HtrA2/Omi, Bax, and Mitochondrial Bax) and endocytoplasmic reticulum (XBP-1s, GRP78, cleaved-Caspase-7 and cleaved-Caspase-12) apoptotic pathways were up-regulated when cells were treated by JA. In addition, a morphological change in the mitochondrion was detected. Furthermore, we found that JA could inhibit DNA synthesis and induce G2/M cell cycle arrest. The expression of G2-to-M transition related proteins, such as CyclinB1 and phosphorylated-CDK1, were reduced. In contrast, the G2-to-M inhibitor p21 was increased in JA-treated cells. Overall, our results suggest that JA can induce mitochondrion- and endocytoplasmic reticulum-mediated apoptosis, and G2/M phase arrest in HepG2 cells, making it a promising therapeutic agent against hepatoma.

  19. The Potent Cdc7-Dbf4 (DDK) Kinase Inhibitor XL413 Has Limited Activity in Many Cancer Cell Lines and Discovery of Potential New DDK Inhibitor Scaffolds


    Nanda Kumar Sasi; Kanchan Tiwari; Fen-Fen Soon; Dorine Bonte; Tong Wang; Karsten Melcher; H. Eric Xu; Michael Weinreich


    Cdc7-Dbf4 kinase or DDK (Dbf4-dependent kinase) is required to initiate DNA replication by phosphorylating and activating the replicative Mcm2-7 DNA helicase. DDK is overexpressed in many tumor cells and is an emerging chemotherapeutic target since DDK inhibition causes apoptosis of diverse cancer cell types but not of normal cells. PHA-767491 and XL413 are among a number of potent DDK inhibitors with low nanomolar IC50 values against the purified kinase. Although XL413 is highly selective fo...

  20. Perspective: Understanding of ripening growth model for minimum residual PbI2 and its limitation in the planar perovskite solar cells (United States)

    Kim, Se-Yun; Jo, Hyo Jeong; Sung, Shi-Joon; Kim, Dae-Hwan


    The power conversion efficiency of lead halide perovskite solar cells recently surpassed 22.1%. In this study, we suggest the perovskite absorber growth mechanism of the two-step process could be explained by an Ostwald ripening growth model for planar-structure perovskite solar cells. We attempt to find out the source of two main problems such as unreacted PbI2 and non-uniformed morphology by the proposed ripening growth mechanism and experimental results. This growth mechanism opens the way toward understanding a key aspect of the photovoltaic operation of high-efficiency, two-step perovskite solar cells.

  1. Intestinal Cell Tight Junctions Limit Invasion of Candida albicans through Active Penetration and Endocytosis in the Early Stages of the Interaction of the Fungus with the Intestinal Barrier.

    Directory of Open Access Journals (Sweden)

    Marianne Goyer

    Full Text Available C. albicans is a commensal yeast of the mucous membranes in healthy humans that can also cause disseminated candidiasis, mainly originating from the digestive tract, in vulnerable patients. It is necessary to understand the cellular and molecular mechanisms of the interaction of C. albicans with enterocytes to better understand the basis of commensalism and pathogenicity of the yeast and to improve the management of disseminated candidiasis. In this study, we investigated the kinetics of tight junction (TJ formation in parallel with the invasion of C. albicans into the Caco-2 intestinal cell line. Using invasiveness assays on Caco-2 cells displaying pharmacologically altered TJ (i.e. differentiated epithelial cells treated with EGTA or patulin, we were able to demonstrate that TJ protect enterocytes against invasion of C. albicans. Moreover, treatment with a pharmacological inhibitor of endocytosis decreased invasion of the fungus into Caco-2 cells displaying altered TJ, suggesting that facilitating access of the yeast to the basolateral side of intestinal cells promotes endocytosis of C. albicans in its hyphal form. These data were supported by SEM observations of differentiated Caco-2 cells displaying altered TJ, which highlighted membrane protrusions engulfing C. albicans hyphae. We furthermore demonstrated that Als3, a hypha-specific C. albicans invasin, facilitates internalization of the fungus by active penetration and induced endocytosis by differentiated Caco-2 cells displaying altered TJ. However, our observations failed to demonstrate binding of Als3 to E-cadherin as the trigger mechanism of endocytosis of C. albicans into differentiated Caco-2 cells displaying altered TJ.

  2. A new loss-of-function allele 28y reveals a role of ARGONAUTE1 in limiting asymmetric division of stomatal lineage ground cell

    Institute of Scientific and Technical Information of China (English)

    Kezhen Yangy; Min Jiangy; Jie Le


    In Arabidopsis thaliana L., stomata are produced through a series of divisions including asymmetric and symmetric divisions. Asymmetric entry division of meristemoid mother cellproduces two daughter cells, the smal er meristemoid and the larger sister cell, a stomatal lineage ground cell(SLGC). Stomatal lineage ground cells can differentiate into epidermal pavement cells but have the potential to divide asymmetrical y, spacing divisions, to create satel ite meristemoids. Peptide ligands and TOO MANY MOUTHS (TMM) and ERECTA family receptors regulate the initiation of stomatal lineages, activity, and orientation of spacing divisions. Here, we reported that a natural mutant 28y displayed an increased stomatal density and index. Using map-based cloning, we identified mutation in ARGONAUTE1 (AGO1) as the cause of 28y phenotypes. Time-lapse tracing of stomatal lineage cells reveals that stomatal overproduction in 28y is caused by the excessive asymmetric spacing division of SLGCs.Further genetic results demonstrated that AGO1 acts down-stream of TMM and negatively regulates the SPCH transcripts, but in a brassinosteroid-independent manner. Upregulation of AGAMOUS-LIKE16 (AGL16) in 28y mutants suggests that AGO1 is required to restrict AGL16-mediated stomatal spacing divisions, an miRNA pathway in addition to ligand-receptor signaling modules.

  3. Effects of CdTe growth conditions and techniques on the efficiency limiting defects and mechanisms in CdTe solar cells (United States)

    Rohatgi, A.; Chou, H. C.; Jokerst, N. M.; Thomas, E. W.; Ferekides, C.; Kamra, S.; Feng, Z. C.; Dugan, K. M.


    CdTe solar cells were fabricated by depositing CdTe films on CdS/SnO2/glass substrates using close-spaced sublimation (CSS) and metalorganic chemical vapor deposition (MOCVD). Te/Cd mole ratio was varied in the range of 0.02 to 6 in the MOCVD growth ambient in an attempt to vary the native defect concentration. Polycrystalline CdTe layers grown by MOCVD and CSS both showed average grain size of about 2 μm. However, the CdTe films grown by CSS were found to be less faceted and more dense compared to the CdTe grown by MOCVD. CdTe growth techniques and conditions had a significant impact on the electrical characteristics of the cells. The CdTe solar cells grown by MOCVD in the Te-rich growth condition and by the CSS technique gave high cell efficiencies of 11.5% and 12.4%, respectively, compared to 6.6% efficient MOCVD cells grown in Cd-rich conditions. This large difference in efficiency is explained on the basis of (a) XRD measurements which showed a higher degree of atomic interdiffusion at the CdS/CdTe interface in high performance devices, (b) Raman measurements which endorsed more uniform and preferred grain orientation by revealing a sharp CdTe TO mode in the high efficiency cells, and (c) carrier transport mechanism which switched from tunneling/interface recombination to depletion region recombination in the high efficiency cells. In this study, Cu/Au layers were evaporated on CdTe for the back contact. Lower efficiency of the Te-rich MOCVD cells, compared to the CSS cells, was attributed to contact related additional loss mechanisms, such as Cd pile-up near Cu/CdTe interface which can give rise to Cd-vacancy defects in the bulk, and higher Cu concentration in the CdTe layer which can cause shunts in the device. Finally, SIMS measurements on the CdTe films of different crystallinity and grain size confirmed that grain boundaries are the main conduits for Cu migration into the CdTe film. Thus larger CdTe grain size or lower grain boundary area per unit volume

  4. c-Kit Expression is Rate-Limiting for Stem Cell Factor-Mediated Disease Progression in Adenoid Cystic Carcinoma of the Salivary Glands

    Directory of Open Access Journals (Sweden)

    Janyaporn Phuchareon


    Full Text Available Adenoid cystic carcinoma (ACC is an aggressive malignant neoplasm of the salivary glands in which c-Kit is overexpressed and activated, although the mechanism for this is as yet unclear. We analyzed 27 sporadic ACC tumor specimens to examine the biologic and clinical significance of c-Kit activation. Mutational analysis revealed expression of wild-type c-Kit in all, eliminating gene mutation as a cause of activation. Because stem cell factor (SCF is c-Kit's sole ligand, we analyzed its expression in the tumor cells and their environment. Immunohistochemistry revealed its presence in c-Kit–positive tumor cells, suggesting an activation of autocrine signaling. We observed a significant induction of ERK1/2 in the cells. SCF staining was also found in other types of non-cancerous cells adjacent to tumors within salivary glands, including stromal fibroblasts, neutrophils, peripheral nerve, skeletal muscle, vascular endothelial cells, mucous acinar cells, and intercalated ducts. Quantitative PCR showed that the top quartile of c-Kit mRNA expression distinguished ACCs from normal salivary tissues and was cross-correlated with short-term poor prognosis. Expression levels of SCF and c-Kit were highly correlated in the cases with perineural invasion. These observations suggest that c-Kit is potentially activated by receptor dimerization upon stimulation by SCF in ACC, and that the highest quartile of c-Kit mRNA expression could be a predictor of poor prognosis. Our findings may support an avenue for c-Kit-targeted therapy to improve disease control in ACC patients harboring the top quartile of c-Kit mRNA expression.

  5. Human Mesenchymal Stem Cell-Derived Microvesicles Prevent the Rupture of Intracranial Aneurysm in Part by Suppression of Mast Cell Activation via a PGE2-Dependent Mechanism. (United States)

    Liu, Jia; Kuwabara, Atsushi; Kamio, Yoshinobu; Hu, Shuling; Park, Jeonghyun; Hashimoto, Tomoki; Lee, Jae-Woo


    Activation of mast cells participates in the chronic inflammation associated with cerebral arteries in intracranial aneurysm formation and rupture. Several studies have shown that the anti-inflammatory effect of mesenchymal stem cells (MSCs) is beneficial for the treatment of aneurysms. However, some long-term safety concerns exist regarding stem cell-based therapy for clinical use. We investigated the therapeutic potential of microvesicles (MVs) derived from human MSCs, anuclear membrane bound fragments with reparative properties, in preventing the rupture of intracranial aneurysm in mice, particularly in the effect of MVs on mast cell activation. Intracranial aneurysm was induced in C57BL/6 mice by the combination of systemic hypertension and intrathecal elastase injection. Intravenous administration of MSC-derived MVs on day 6 and day 9 after aneurysm induction significantly reduced the aneurysmal rupture rate, which was associated with reduced number of activated mast cells in the brain. A23187-induced activation of both primary cultures of murine mast cells and a human mast cell line, LAD2, was suppressed by MVs treatment, leading to a decrease in cytokine release and tryptase and chymase activities. Upregulation of prostaglandin E2 (PGE2) production and E-prostanoid 4 (EP4) receptor expression were also observed on mast cells with MVs treatment. Administration of an EP4 antagonist with the MVs eliminated the protective effect of MVs against the aneurysmal rupture in vivo. Human MSC-derived MVs prevented the rupture of intracranial aneurysm, in part due to their anti-inflammatory effect on mast cells, which was mediated by PGE2 production and EP4 activation. Stem Cells 2016;34:2943-2955.

  6. Opportunities and limits of the one gene approach: the ability of Atoh1 to differentiate and maintain hair cells depends on the molecular context.

    Directory of Open Access Journals (Sweden)

    Israt eJahan


    Full Text Available Atoh1 (Math1 was the first gene discovered in ear development that showed no hair cell (HC differentiation when absent and could induce HC differentiation when misexpressed. These data implied that Atoh1 was both necessary and sufficient for hair cell development. However, other gene mutations also result in loss of initially forming HCs, notably null mutants for Pou4f3, Barhl1 and Gfi1. HC development and maintenance also depend on the expression of other genes (Sox2, Eya1, Gata3, Pax2 and several genes have been identified that can induce HCs when misexpressed (Jag1 or knocked out (Lmo4. In the ear Atoh1 is not only expressed in HCs but also in some supporting cells and neurons that do not differentiate into HCs. Simple removal of one gene, Neurod1, can de-repress Atoh1 and turns those neurons into HCs suggesting that Neurod1 blocks Atoh1 function in neurons. Atoh1 expression in inner pillar cells may also be blocked by too many Hes/Hey factors but conversion into HCs has only partially been achieved through Hes/Hey removal. Detailed analysis of cell cycle exit confirmed an apex to base cell cycle exit progression of HCs of the organ of Corti. In contrast, Atoh1 expression progresses from the base towards the apex with a variable delay relative to the cell cycle exit. Most HCs exit the cell cycle and are thus defined as precursors before Atoh1 is expressed. Atoh1 is a potent differentiation factor but can differentiate and maintain HCs only in the ear and when other factors are co-expressed. Upstream factors are essential to regulate Atoh1 level of expression duration while downstream, co-activated by other factors, will define the context of Atoh1 action. We suggest that these insights need to be taken into consideration and approaches beyond the simple Atoh1 expression need to be designed able to generate the radial and longitudinal variations in hair cell types for normal function of the organ of Corti.

  7. Forward and reverse transduction at the limit of sensitivity studied by correlating electrical and mechanical fluctuations in frog saccular hair cells. (United States)

    Denk, W; Webb, W W


    The spontaneous fluctuations of the intracellular voltage and the position of the sensory hairbundle were measured concurrently using intracellular microelectrodes and an optical differential micro interferometer. Magnitude and frequency distribution of the hair bundles' spontaneous motion suggest that it consists mostly of Brownian motion. The electrical noise, however, exceeds the value expected for thermal Johnson noise by several orders of magnitude, and its frequency distribution reflects the transduction tuning properties of the hair cells. Frequently, a strong correlation was observed between the fluctuations of the hair bundle position and the intracellular electrical noise. From the properties of the correlation and from experiments involving mechanical stimulation we conclude that in most cases mechano-electrical transduction of the bundles' Brownian motion causes this correlation. Small signal transduction sensitivities ranged from 18 to 500 microV/nm. Bundle motion that was observed in response to current injection in more than half of the cells suggests the existence of a fast reverse (electro-mechanical) transduction mechanism to be common in these cells. The sensitivities could be as high as 600 pm of bundle deflection per millivolt of membrane potential change. In a significant minority (4 in 44) of cells, all showing excess electrical noise, we found 'non-causal' components of the electro-mechanical correlation, and in two of those cells narrow-band bundle motion in excess of their thermal motion at frequencies coincident with peaks in the intracellular noise was observed.

  8. 有限稀释克隆法培养分离人牙周膜干细胞实验研究%Experimental study of human periodontal stem cells cloning isolated and cultured by limited dilution method

    Institute of Scientific and Technical Information of China (English)

    封艳; 牛巧丽; 尹宏斌; 钟良军; 赵今


    Objective To obtain human periodontal ligament stem cell (hPDLSCs)cloning strain by limited dilution method for a preliminary research on its biological characteristics.Methods The limiting dilution method was adopted to separate gradually and screening hPDLSCs cloning from human periodontal liga-ment cells;the osteogenic capability in vitro,morphology and colony formation of the isolated hPDLSCs were observed;STRO-1,CD146 and other signs of protein expression were detected.Results The hP-DLSCs cloning obtained by limiting dilution similar were characteristic of the morphology of adult stem cells;Cell cycle analysis showed a slow cyclicality;STRO-1,CD146 were positively expressed by immu-nocytochemical staining;the cells induced by mineralization can express a variety of markers of bone pro-teins.Conclusion The purification of limited dilution can obtain hPDLSCs with the same features of adult stem cells in terms of cell cycle,phenotypic and osteogenic differentiation capacity.%目的:探讨有限稀释克隆法培养分离人牙周膜干细胞株的实验方法,并对其生物学特性进行初步研究。方法采用有限稀释克隆法对人牙周膜细胞逐步分离筛选,观察分离出的人牙周膜干细胞形态及克隆形成情况,并对其细胞周期、STRO-1、CD146等标志蛋白的表达进行检测,检测其体外诱导成骨的能力。结果通过有限稀释法获得人牙周膜干细胞克隆具有成体干细胞的形态特征;细胞周期分析呈慢周期性;免疫细胞化学染色证实 STRO-1、CD146及 Vimentin 均为阳性染色,矿化诱导证实该细胞可以表达多种骨蛋白标记物。结论采用有限稀释克隆法分离纯化可以获得成体干细胞所具有的细胞周期、表型及骨向分化能力等特点的牙周膜干细胞株。

  9. Cationic liposomes promote antigen cross-presentation in dendritic cells by alkalizing the lysosomal pH and limiting the degradation of antigens. (United States)

    Gao, Jie; Ochyl, Lukasz J; Yang, Ellen; Moon, James J


    Cationic liposomes (CLs) have been widely examined as vaccine delivery nanoparticles since they can form complexes with biomacromolecules, promote delivery of antigens and adjuvant molecules to antigen-presenting cells (APCs), and mediate cellular uptake of vaccine components. CLs are also known to trigger antigen cross-presentation - the process by which APCs internalize extracellular protein antigens, degrade them into minimal CD8(+) T-cell epitopes, and present them in the context of major histocompatibility complex-I (MHC-I). However, the precise mechanisms behind CL-mediated induction of cross-presentation and cross-priming of CD8(+) T-cells remain to be elucidated. In this study, we have developed two distinct CL systems and examined their impact on the lysosomal pH in dendritic cells (DCs), antigen degradation, and presentation of peptide:MHC-I complexes to antigen-specific CD8(+) T-cells. To achieve this, we have used 3β-[N-(N',N'-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) as the prototypical components of CLs with tertiary amine groups and compared the effect of CLs and anionic liposomes on lysosomal pH, antigen degradation, and cross-presentation by DCs. Our results showed that CLs, but not anionic liposomes, elevated the lysosomal pH in DCs and reduced antigen degradation, thereby promoting cross-presentation and cross-priming of CD8(+) T-cell responses. These studies shed new light on CL-mediated cross-presentation and suggest that intracellular fate of vaccine components and subsequent immunological responses can be controlled by rational design of nanomaterials.

  10. Multifrequency permittivity measurements enable on-line monitoring of changes in intracellular conductivity due to nutrient limitations during batch cultivations of CHO cells. (United States)

    Ansorge, Sven; Esteban, Geoffrey; Schmid, Georg


    Lab and pilot scale batch cultivations of a CHO K1/dhfr(-) host cell line were conducted to evaluate on-line multifrequency permittivity measurements as a process monitoring tool. The beta-dispersion parameters such as the characteristic frequency (f(C)) and the permittivity increment (Deltaepsilon(max)) were calculated on-line from the permittivity spectra. The dual-frequency permittivity signal correlated well with the off-line measured biovolume and the viable cell density. A significant drop in permittivity was monitored at the transition from exponential growth to a phase with reduced growth rate. Although not reflected in off-line biovolume measurements, this decrease coincided with a drop in OUR and was probably caused by the depletion of glutamine and a metabolic shift occurring at the same time. Sudden changes in cell density, cell size, viability, capacitance per membrane area (C(M)), and effects caused by medium conductivity (sigma(m)) could be excluded as reasons for the decrease in permittivity. After analysis of the process data, a drop in f(C) as a result of a fall in intracellular conductivity (sigma(i)) was identified as responsible for the observed changes in the dual-frequency permittivity signal. It is hypothesized that the beta-dispersion parameter f(C) is indicative of changes in nutrient availability that have an impact on intracellular conductivity sigma(i). On-line permittivity measurements consequently not only reflect the biovolume but also the physiological state of mammalian cell cultures. These findings should pave the way for a better understanding of the intracellular state of cells and render permittivity measurements an important tool in process development and control.

  11. Cationic liposomes promote antigen cross-presentation in dendritic cells by alkalizing the lysosomal pH and limiting the degradation of antigens (United States)

    Gao, Jie; Ochyl, Lukasz J; Yang, Ellen; Moon, James J


    Cationic liposomes (CLs) have been widely examined as vaccine delivery nanoparticles since they can form complexes with biomacromolecules, promote delivery of antigens and adjuvant molecules to antigen-presenting cells (APCs), and mediate cellular uptake of vaccine components. CLs are also known to trigger antigen cross-presentation – the process by which APCs internalize extracellular protein antigens, degrade them into minimal CD8+ T-cell epitopes, and present them in the context of major histocompatibility complex-I (MHC-I). However, the precise mechanisms behind CL-mediated induction of cross-presentation and cross-priming of CD8+ T-cells remain to be elucidated. In this study, we have developed two distinct CL systems and examined their impact on the lysosomal pH in dendritic cells (DCs), antigen degradation, and presentation of peptide:MHC-I complexes to antigen-specific CD8+ T-cells. To achieve this, we have used 3β-[N-(N′,N′-dimethylaminoethane)-carbamoyl] cholesterol (DC-Chol) and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) as the prototypical components of CLs with tertiary amine groups and compared the effect of CLs and anionic liposomes on lysosomal pH, antigen degradation, and cross-presentation by DCs. Our results showed that CLs, but not anionic liposomes, elevated the lysosomal pH in DCs and reduced antigen degradation, thereby promoting cross-presentation and cross-priming of CD8+ T-cell responses. These studies shed new light on CL-mediated cross-presentation and suggest that intracellular fate of vaccine components and subsequent immunological responses can be controlled by rational design of nanomaterials. PMID:28243087

  12. An Alternative Corrosion Resistance Test Method for Solar Cells and Interconnection Materials Limiting the Number of Long-lasting and Expensive Damp-Heat Climate Chamber Tests

    Energy Technology Data Exchange (ETDEWEB)

    Van Aken, B.B.; Gouwen, R.J.; Veldman, D.; Bende, E.E.; Eerenstein, W. [ECN Solar Energy, Petten (Netherlands)


    Damp-heat testing of PV modules is a time-consuming process, taking months. We present an alternative test method: electrochemical noise (EcN) measurements. Data acquisition times vary between minutes for direct exposure to several tens of hours for encapsulated samples. EcN measurements are presented for several solar cell concepts and different environments. We have found that the degradation in damp-heat testing is proportional to the electrochemical noise signal. In conclusion, the electrochemical noise measurements are a fast, versatile tool to test the corrosion resistance of solar cells, which can be tested for different environments including encapsulation.

  13. Schizosaccharomyces pombe cell division cycle under limited glucose requires Ssp1 kinase, the putative CaMKK, and Sds23, a PP2A-related phosphatase inhibitor. (United States)

    Hanyu, Yuichiro; Imai, Kumiko K; Kawasaki, Yosuke; Nakamura, Takahiro; Nakaseko, Yukinobu; Nagao, Koji; Kokubu, Aya; Ebe, Masahiro; Fujisawa, Asuka; Hayashi, Takeshi; Obuse, Chikashi; Yanagida, Mitsuhiro


    Calcium/calmodulin-dependent protein kinase (CaMK) is required for diverse cellular functions, and similar kinases exist in fungi. Although mammalian CaMK kinase (CaMKK) activates CaMK and also evolutionarily-conserved AMP-activated protein kinase (AMPK), CaMKK is yet to be established in yeast. We here report that the fission yeast Schizosaccharomyces pombe Ssp1 kinase, which controls G2/M transition and response to stress, is the putative CaMKK. Ssp1 has a CaM binding domain (CBD) and associates with 14-3-3 proteins as mammalian CaMKK does. Temperature-sensitive ssp1 mutants isolated are defective in the tolerance to limited glucose, and this tolerance requires the conserved stretch present between the kinase domain and CBD. Sds23, multi-copy suppressor for mutants defective in type 1 phosphatase and APC/cyclosome, also suppresses the ssp1 phenotype, and is required for the tolerance to limited glucose. We demonstrate that Sds23 binds to type 2A protein phosphatases (PP2A) and PP2A-related phosphatase Ppe1, and that Sds23 inhibits Ppe1 phosphatase activity. Ssp1 and Ppe1 thus seem to antagonize in utilizing limited glucose. We also show that Ppk9 and Ssp2 are the catalytic subunits of AMPK and AMPK-related kinases, respectively, which bind to common beta-(Amk2) and gamma-(Cbs2) subunits.

  14. Part I: Minicircle vector technology limits DNA size restrictions on ex vivo gene delivery using nanoparticle vectors: Overcoming a translational barrier in neural stem cell therapy. (United States)

    Fernandes, Alinda R; Chari, Divya M


    Genetically engineered neural stem cell (NSC) transplant populations offer key benefits in regenerative neurology, for release of therapeutic biomolecules in ex vivo gene therapy. NSCs are 'hard-to-transfect' but amenable to 'magnetofection'. Despite the high clinical potential of this approach, the low and transient transfection associated with the large size of therapeutic DNA constructs is a critical barrier to translation. We demonstrate for the first time that DNA minicircles (small DNA vectors encoding essential gene expression components but devoid of a bacterial backbone, thereby reducing construct size versus conventional plasmids) deployed with magnetofection achieve the highest, safe non-viral DNA transfection levels (up to 54%) reported so far for primary NSCs. Minicircle-functionalized magnetic nanoparticle (MNP)-mediated gene delivery also resulted in sustained gene expression for up to four weeks. All daughter cell types of engineered NSCs (neurons, astrocytes and oligodendrocytes) were transfected (in contrast to conventional plasmids which usually yield transfected astrocytes only), offering advantages for targeted cell engineering. In addition to enhancing MNP functionality as gene delivery vectors, minicircle technology provides key benefits from safety/scale up perspectives. Therefore, we consider the proof-of-concept of fusion of technologies used here offers high potential as a clinically translatable genetic modification strategy for cell therapy.

  15. Exploring the limits of optical microscopy: live cell and superresolution fluorescence microscopy of HIV-1 Transfer Between T lymphocytes Across the Virological Synapse (United States)

    McNerney, Gregory Paul

    Human immunodeficiency virus 1 (HIV-1) is a human retrovirus that efficiently, albeit gradually, overruns the immune system. An already infected T lymphocyte can latch onto another T lymphocyte whereby creating a virological synapse (VS); this junction drives viral assembly and transfer to the target cell in batches in an efficient, protective manor. My Ph.D. doctoral thesis focused on studying this transmission mechanism using advanced optical imaging modalities and the fully infectious fluorescent clone HIV Gag-iGFP. T lymphocytes are non-adherent cells (˜10 um thick) and the viral transmission process is fairly dynamic, hence we employed a custom spinning disk confocal microscope that revealed many interesting characteristics of this cooperative event. This methodology has low throughput as cell contact and transfer is at random. Optical tweezers was then added to the microscope to directly initiate cell contact at will. To assess when viral maturation occurs post-transfer, an optical assay based off of Forster resonance energy transfer was developed to monitor maturation. Structured illumination microscopy was further used to image the process at higher resolution and it showed that viral particles are not entering existing degradative compartments. Non-HIV-1 applications of the optical technologies are also reviewed.

  16. Outcomes from monitoring of patients on antiretroviral therapy in resource-limited settings with viral load, CD4 cell count, or clinical observation alone: a computer simulation model

    DEFF Research Database (Denmark)

    Phillips, Andrew N; Pillay, Deenan; Miners, Alec H;


    BACKGROUND: In lower-income countries, WHO recommends a population-based approach to antiretroviral treatment with standardised regimens and clinical decision making based on clinical status and, where available CD4 cell count, rather than viral load. Our aim was to study the potential consequenc...

  17. Is the availability of substrate for the tricarboxylic acid cycle a limiting factor for uncoupled respiration in sycamore (Acer pseudoplatanus) cells? (United States)

    Journet, E P; Bligny, R; Douce, R


    Protoplasts obtained from sycamore (Acer pseudoplatanus) cell suspensions were found to be highly intact and to retain a high rate of O2 consumption. If the protoplasts were taken up and expelled through a fine nylon mesh, all the protoplasts were ruptured, leaving the fragile amyloplasts largely intact. Distribution of enzymes of glycolysis in plastids and soluble phase of sycamore protoplasts indicated that the absolute maximum activity for each glycolytic enzyme under optimum conditions exceeded the estimates of the maximal rate at which sycamore cells oxidize triose phosphate. Passage of protoplasts through the fine nylon mesh produced a 3-5-fold decrease in O2 consumption. However, addition of saturating amounts of respiratory substrates and ADP restored an O2 consumption equal to that observed with uncoupled intact protoplasts. Taken together, these results demonstrated that neither the overall capacity of the glycolytic enzymes in sycamore cells nor the availability of respiratory substrates for the mitochondria is ultimately responsible for determining the rate of uncoupled respiration in sycamore cells.

  18. Pseudo-2D polarization model of polymer exchange membrane fuel cell including mass transport limitation due to flooding : numerical simulation and comparison with experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Maranzana, G.; Chupin, S.; Colinart, T.; Lottin, O.; Didierjean, S. [Nancy-Univ., Vandoeuvre (France). Laboratoire d' Energetique et de Mecanique Theorique et Appliquee


    The electrodes of proton membrane exchange (PEM) fuel cells are fed by gases, whose properties are changing during their transition from the inlet to the outlet of the channels. For example, the reactant concentration decreases and the water concentration increases, the total pressure diminishes, the temperature is dependent on the local current density, and liquid water may appear or disappear. The electrode performances are not uniform, which can have impacts on the entire performances of the cell or on its durability. In order to observe and model these non-homogeneities, this paper presented an experimental study that involved designing, building, and testing a single PEM fuel cell that allowed measurement of both current density and temperature fields along the gas channels. The fuel cell was made of transparent polymethyl methacrylate (PMMA) so that the location of liquid water appearance in the channels could be observed. The first experimental results were compared with the predictions of a pseudo-2D model which assumed mass transfer to occur in the direction perpendicular to the membrane, but took into account the variations in concentrations, in total pressure, and in temperatures along the gas channels. It was concluded that the current density distribution depended greatly on water management. 10 refs., 3 figs.

  19. Array Antenna Limitations

    CERN Document Server

    Jonsson, B L G; Hussain, N


    This letter defines a physical bound based array figure of merit that provides a tool to compare the performance of both single and multi-band array antennas with respect to return-loss, thickness of the array over the ground-plane, and scan-range. The result is based on a sum-rule result of Rozanov-type for linear polarization. For single-band antennas it extends an existing limit for a given fixed scan-angle to include the whole scan-range of the array, as well as the unit-cell structure in the bound. The letter ends with an investigation of the array figure of merit for some wideband and/or wide-scan antennas with linear polarization. We find arrays with a figure of merit >0.6 that empirically defines high-performance antennas with respect to this measure.

  20. A novel method based on click chemistry, which overcomes limitations of cell cycle analysis by classical determination of BrdU incorporation, allowing multiplex antibody staining. (United States)

    Cappella, Paolo; Gasparri, Fabio; Pulici, Maurizio; Moll, Jürgen


    Quantification of BrdU incorporation into DNA is a widely used technique to assess the cell cycle status of cells. DNA denaturation is required for BrdU detection with the drawback that most protein epitopes are destroyed and classical antibody staining techniques for multiplex analysis are not possible. To address this issue we have developed a novel method that overcomes the DNA denaturation step but still allows detection of BrdU. Cells were pulsed for a short time by 5-ethynyl-2'-deoxyuridine, which is incorporated into DNA. The exposed nucleotide alkyne group of DNA was then derivatized in physiologic conditions by the copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) using BrdU azides. The resulting DNA-bound bromouracil moiety was subsequently detected by commercial anti-BrdU mAb without the need for a denaturation step. Continuous labeling with EdU showed a slightly increased anti-proliferative activity compared to BrdU. However, using a lower concentration of EdU for labeling can compensate for this. Alkynyl tags could be detected quickly by a highly specific reaction using BrdU azides. Fluorescence quenching by the DNA dye PI using both BrdU azides was negligible. Our labeling method is suitable for FCM and HCA and shows a higher signal to noise ratio than other methods. This method also allowed multiplex analysis by simultaneous detection of EdU-BrdU, caspase-3, and phospho-histone 3 mAbs, proving sensitivity and feasibility of this new technique. In addition, it has the potential for use in vivo, as exemplified for bone marrow studies. We have established a new method to determine the position of cells in the cell cycle. This is superior when compared to traditional BrdU detection since it allows multiplex analysis, is more sensitive and shows less quenching with PI. The method provides new opportunities to investigate changes in protein expression at different cell cycle stages using pulse labeling experiments.

  1. Restriction of GAGE protein expression to subpopulations of cancer cells is independent of genotype and may limit the use of GAGE proteins as targets for cancer immunotherapy

    DEFF Research Database (Denmark)

    Gjerstorff, M F; Johansen, L E; Nielsen, O


    The GAGE cancer testis antigen gene family encodes products that can be recognized by autologous T cells, and GAGE proteins have been suggested as potential targets for cancer immunotherapy. Analysis of GAGE expression in tumours has primarily been performed at the level of gene transcription......, whereas little is known about GAGE expression at the protein level. To evaluate the potential of GAGE proteins as targets for cancer-specific immunotherapy, we studied the expression of these proteins in normal and malignant cells/tissues using a novel panel of monoclonal antibodies. Immunohistochemical...... analysis of more than 250 cancer specimens demonstrated that GAGE proteins were frequently expressed in numerous cancer types and correlated with the expression of the cancer testis antigens MAGE-A1 and NY-ESO-1. Significant intercellular and subcellular differences in GAGE protein levels were observed...

  2. ATR-p53 restricts homologous recombination in response to replicative stress but does not limit DNA interstrand crosslink repair in lung cancer cells.

    Directory of Open Access Journals (Sweden)

    Bianca M Sirbu

    Full Text Available Homologous recombination (HR is required for the restart of collapsed DNA replication forks and error-free repair of DNA double-strand breaks (DSB. However, unscheduled or hyperactive HR may lead to genomic instability and promote cancer development. The cellular factors that restrict HR processes in mammalian cells are only beginning to be elucidated. The tumor suppressor p53 has been implicated in the suppression of HR though it has remained unclear why p53, as the guardian of the genome, would impair an error-free repair process. Here, we show for the first time that p53 downregulates foci formation of the RAD51 recombinase in response to replicative stress in H1299 lung cancer cells in a manner that is independent of its role as a transcription factor. We find that this downregulation of HR is not only completely dependent on the binding site of p53 with replication protein A but also the ATR/ATM serine 15 phosphorylation site. Genetic analysis suggests that ATR but not ATM kinase modulates p53's function in HR. The suppression of HR by p53 can be bypassed under experimental conditions that cause DSB either directly or indirectly, in line with p53's role as a guardian of the genome. As a result, transactivation-inactive p53 does not compromise the resistance of H1299 cells to the interstrand crosslinking agent mitomycin C. Altogether, our data support a model in which p53 plays an anti-recombinogenic role in the ATR-dependent mammalian replication checkpoint but does not impair a cell's ability to use HR for the removal of DSB induced by cytotoxic agents.

  3. Silicon photomultiplier (SPM) detection of low-level bioluminescence for the development of deployable whole-cell biosensors: Possibilities and limitations


    Li, Huaqing; Lopes, Nicholas; Moser, Scott; Sayler, Gary; Ripp, Steven


    Whole-cell bacterial bioreporters await miniaturized photon counting modules with high sensitivity and robust compatible hardware to fulfill their promise of versatile, on-site biosensor functionality. In this study, we explore the photon counting readout properties of the silicon photomultiplier (SPM) with a thermoelectric cooler and the possibilities of detecting low-level bioluminescent signals. Detection performance was evaluated through a simulated LED light source and the bioluminescenc...

  4. Reactive oxygen species and autophagy associated apoptosis and limitation of clonogenic survival induced by zoledronic acid in salivary adenoid cystic carcinoma cell line SACC-83.

    Directory of Open Access Journals (Sweden)

    Xi-Yuan Ge

    Full Text Available Salivary adenoid cystic carcinoma is an epithelial tumor in the head and neck region. Despite its slow growth, patients with salivary adenoid cystic carcinoma exhibit poor long term survival because of a high rate of distant metastasis. Lung and bone are common distant metastasis sites. Zoledronic acid, a third generation bisphosphonate, has been used for tumor-induced osteolysis due to bone metastasis and has direct antitumor activity in several human neoplasms. Here, we observed that zoledronic acid inhibited salivary adenoid cystic carcinoma cell line SACC-83 xenograft tumor growth in nude mice. In vitro, zoledronic acid induced apoptosis and reduced clonogenic survival in SACC-83. Flow cytometry and western blotting indicated that the cell cycle was arrested at G0/G1. Zoledronic acid treatment upregulated reactive oxygen species as well as the autophagy marker protein LC-3B. Reactive oxygen species scavenger N-acetylcysteine and autophagy antagonist 3-methyladenine decreased zoledronic acid-induced apoptosis and increased clonogenic survival. Silencing of the autophagy related gene Beclin-1 also decreased zoledronic acid-induced apoptosis and inhibition of clonogenic formation. In addition, isobolographic analysis revealed synergistic effects on apoptosis when zoledronic acid and paclitaxel/cisplatin were combined. Taken together, our results suggest that zoledronic acid induced apoptosis and reduced clonogenic survival via upregulation of reactive oxygen species and autophagy in the SACC-83 cell line. Thus, zoledronic acid should be considered a promising drug for the treatment of salivary adenoid cystic carcinoma.

  5. Limited influence of aspirin intake on mast cell activation in patients with food-dependent exercise-induced anaphylaxis: comparison using skin prick and histamine release tests. (United States)

    Fukunaga, Atsushi; Shimizu, Hideki; Tanaka, Mami; Kikuzawa, Ayuko; Tsujimoto, Mariko; Sekimukai, Akiko; Yamashita, Junji; Horikawa, Tatsuya; Nishigori, Chikako


    Food-dependent exercise-induced anaphylaxis (FDEIA) is a severe systemic syndrome induced by physical exercise after ingesting causative food. Aspirin is a well-known trigger for anaphylaxis in patients with FDEIA. Possible mechanisms by which symptoms are aggravated by aspirin include enhanced antigen absorption and mast cell activation. The aim of this study was to determine whether aspirin intake has an influence on mast cell/basophil activation in patients with FDEIA. Provocation tests revealed that adding aspirin to the causative food challenge in 7 of 9 (77.8%) patients with FDEIA provoked symptoms. In most cases, pretreatment with aspirin did not enhance skin tests (71.4%) or histamine release tests (88.9%) with food allergen challenges. The study confirms that histamine release and skin prick tests can be adjunctive tools for diagnosing FDEIA. In addition, our results suggest that exacerbation of FDEIA symptoms by aspirin is not mediated by direct effects of aspirin on mast cell/basophil activation.

  6. Search for limiting factors in the RNAi pathway in silkmoth tissues and the Bm5 cell line: the RNA-binding proteins R2D2 and Translin. (United States)

    Swevers, Luc; Liu, Jisheng; Huvenne, Hanneke; Smagghe, Guy


    RNA interference (RNAi), an RNA-dependent gene silencing process that is initiated by double-stranded RNA (dsRNA) molecules, has been applied with variable success in lepidopteran insects, in contrast to the high efficiency achieved in the coleopteran Tribolium castaneum. To gain insight into the factors that determine the efficiency of RNAi, a survey was carried out to check the expression of factors that constitute the machinery of the small interfering RNA (siRNA) and microRNA (miRNA) pathways in different tissues and stages of the silkmoth, Bombyx mori. It was found that the dsRNA-binding protein R2D2, an essential component in the siRNA pathway in Drosophila, was expressed at minimal levels in silkmoth tissues. The silkmoth-derived Bm5 cell line was also deficient in expression of mRNA encoding full-length BmTranslin, an RNA-binding factor that has been shown to stimulate the efficiency of RNAi. However, despite the lack of expression of the RNA-binding proteins, silencing of a luciferase reporter gene was observed by co-transfection of luc dsRNA using a lipophilic reagent. In contrast, gene silencing was not detected when the cells were soaked in culture medium supplemented with dsRNA. The introduction of an expression construct for Tribolium R2D2 (TcR2D2) did not influence the potency of luc dsRNA to silence the luciferase reporter. Immunostaining experiments further showed that both TcR2D2 and BmTranslin accumulated at defined locations within the cytoplasm of transfected cells. Our results offer a first evaluation of the expression of the RNAi machinery in silkmoth tissues and Bm5 cells and provide evidence for a functional RNAi response to intracellular dsRNA in the absence of R2D2 and Translin. The failure of TcR2D2 to stimulate the intracellular RNAi pathway in Bombyx cells is discussed.

  7. HOME Income Limits (United States)

    Department of Housing and Urban Development — HOME Income Limits are calculated using the same methodology that HUD uses for calculating the income limits for the Section 8 program. These limits are based on HUD...

  8. A multidisciplinary approach to the management of temporomandibular joint ankylosis in a sickle-cell anemia patient in a resource-limited setting. (United States)

    Braimah, Ramat Oyebunmi; Oladejo, Taoreed; Olarinoye, Timothy Oyetunde; Adetoye, Adedapo Omowonuola; Osho, Patrick Olanrewaju


    This report describes the multidisciplinary management of a 35-year-old female sickle-cell anemia patient who had unilateral bony ankylosis of the left temporomandibular joint secondary to septic arthritis. She was managed by a team comprising of maxillofacial surgeons, anesthetists, otorhinolaryngologist, and hematologist. Unilateral left interpositional arthroplasty and ipsilateral coronoidectomy through a postrami approach were done and followed by aggressive jaw physiotherapy in the postsurgical period. No perioperative morbidity was encountered. Mouth opening of 3.5 cm was achieved and maintained 7 months after surgery. Challenges and rationale for the use of a multidisciplinary team approach in treatment of such cases were discussed.

  9. Limited impact of the thymus on immunological recovery during and after chemotherapy in patients with diffuse large B-cell lymphoma

    DEFF Research Database (Denmark)

    Vedel, S.J.; Tholstrup, D.; Kolte, L.;


    To investigate the impact of thymus on immunological recovery after dose-dense chemotherapy a prospective study of 17 patients diagnosed with diffuse large B-cell lymphoma (DLBCL) was conducted. Patients were monitored before, during and until 3 months after chemotherapy. The thymus was visualized...... using computer tomographic scans. Patients were divided into two groups according to thymic size, one group comprising of patients without detectable thymus and one group of patients with detectable thymus. Naïve CD4 and CD8 counts were measured by flow cytometry, and to measure thymic output...

  10. Blockage of Autophagy in C6 Glioma Cells Enhanced Radiosensitivity Possibly by Attenuating DNA-PK-Dependent DSB Due to Limited Ku Nuclear Translocation and DNA Binding. (United States)

    Liu, C; He, W; Jin, M; Li, H; Xu, H; Liu, H; Yang, K; Zhang, T; Wu, G; Ren, J


    Glioblastoma multiforme (GBM) is the most lethal brain tumor and notorious for its resistance to ionizing radiation (IR). Recent evidence suggests that one possible mechanism that enables resistance to IR and protects cells against therapeutic stress is cellular autophagy. The molecular basis for this pro-survival function, however, remains elusive. Herein, we report a molecular mechanism by which IR-induced autophagy accelerates the repair of DNA double-strand breaks (DSB). We demonstrate that IR induces the accumulation of autophagosomes, which is accompanied by elevated expression of autophagyrelated genes beclin-1, atg5, atg7, and atg12. Beclin-1 knockdown impaired the induction of IR-mediated autophagy and significantly sensitized glioma cells to radiation therapy in vitro and in vivo. Furthermore, our data is the first to demonstrate that the radiosensitizing effect of beclin-1 knockdown may result from the disruption of nuclear translocation and DNA binding activity of Ku proteins and consequent attenuation of DSB repair. Our findings help advance our understanding of the molecular mechanisms underlying IR-induced autophagy and provide a promising adjunctive therapeutic strategy for the radiosensitization of malignant glioma.

  11. Passive immitance limiters


    Filinyuk N. A.; Lischinskaya L. B.; Chekhmestruk R. Yu.


    The paper presents quadripole R, L, C immittance limiters, in which output immittance to the certain value depends on the input immittance. A classification of immittance limiters is given. Basic parameters are considered: low and high levels of output immittance limiters; low and high values of input immittance, corresponding to low and high levels of limitation, accordingly; range of possible values of output immittance; steepness of immittance limiters; time of wearing-out (or delay); high...

  12. Endemicity and phylogeny of the human T cell lymphotropic virus type II subtype A from the Kayapo Indians of Brazil: evidence for limited regional dissemination. (United States)

    Switzer, W M; Black, F L; Pieniazek, D; Biggar, R J; Lal, R B; Heneine, W


    Long terminal repeat (LTR)-based restriction fragment length polymorphism (RFLP) analysis of human T cell lymphotropic virus type II (HTLV-II) from 17 seropositive Kayapo Indians from Brazil showed that all 17 samples contained a unique HTLV-IIa subtype (A-II). Additional RFLP screening demonstrated the presence of this subtype in two of three Brazilian blood donors and a Mexican prostitute and her child. In contrast, 129 samples from blood donors and intravenous drug users (IDUs) from the United States, two Pueblo Indian samples, five samples from Norwegian IDUs, and two samples from blood donors from Denmark were all found to be a different HTLV-IIa subtype (A-III). Phylogenetic analysis of two Kayapo and one Mexican LTR sequences showed that they cluster with a subtype A-II sequence from a Brazilian blood donor and with sequences from two prostitutes from Ghana and Cameroon. These results demonstrate that infection with the A-II subtype is endemic among the Kayapo Amerindians, has disseminated to non-Indian populations in Brazil, and is also present in Mexico. Furthermore, the A-II subtype does not appear to represent an origin for the HTLV-IIa infection in urban areas of the United States and Europe. This study provides evidence that HTLV-IIa may be a Paleo-Indian subtype as previously suggested for HTLV-IIb.

  13. Taking X-ray Diffraction to the Limit: Macromolecular Structures from Femtosecond X-ray Pulses and Diffraction Microscopy of Cells with Synchrotron Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Chapman, H N; Miao, J; Kirz, J; Sayre, D; Hodgson, K O


    The methodology of X-ray crystallography has recently been successfully extended to the structure determination of non-crystalline specimens. The phase problem was solved by using the oversampling method, which takes advantage of ''continuous'' diffraction pattern from non-crystalline specimens. Here we review the principle of this newly developed technique and discuss the ongoing experiments of imaging non-periodic objects, like cells and cellular structures using coherent and bright X-rays from the 3rd generation synchrotron radiation. In the longer run, the technique may be applied to image single biomolecules by using the anticipated X-ray free electron lasers. Computer simulations have so far demonstrated two important steps: (1) by using an extremely intense femtosecond X-ray pulse, a diffraction pattern can be recorded from a macromolecule before radiation damage manifests itself, and (2) the phase information can be ab initio retrieved from a set of calculated noisy diffraction patterns of single protein molecules.

  14. Limited role of interim PET/CT in patients with diffuse large B-cell lymphoma treated with R-CHOP. (United States)

    Yoo, Changhoon; Lee, Dae Ho; Kim, Jeong Eun; Jo, Jungmin; Yoon, Dok Hyun; Sohn, Byeong Seok; Kim, Sang-We; Lee, Jung-Shin; Suh, Cheolwon


    Positron emission tomography (PET) has been found useful in monitoring response to treatment of malignant lymphoma. We investigated the ability of interim PET to monitor response to standard dose R-CHOP chemotherapy in chemotherapy-naïve patients with diffuse large B-cell lymphoma (DLBCL). Between March 2004 and April 2009, 155 DLBCL patients treated with R-CHOP and available for interim and post-treatment PET/CT were identified and included in this analysis. Response, progression-free survival (PFS), and overall survival (OS) were compared between interim PET/CT-negative and positive group, and among three patient groups which were categorized based on their interim and post-treatment PET/CT: those with early metabolic complete response (mCR), delayed mCR, and never mCR. Interim PET/CT-negative patients (n=100) showed superior CR rates to interim PET/CT-positive patients (n=55; 93% vs 62%, Pinterim PET/CT-negative and positive group. We categorized patients into three groups, with 100 (64%) in the early mCR group, 35 (23%) in the delayed mCR group, and 20 (13%) in the never mCR group. Early mCR and delayed mCR group did not differ significantly in PFS (P=0.84) or OS (P=0.20). However, the survival outcome in the never mCR group was significantly inferior to the combined early and delayed mCR group. The result from this study suggests that interim PET/CT might be an inappropriate tool for designing risk-adaptive therapy in chemotherapy-naïve DLBCL patients treated with R-CHOP. Prospective trials should be performed to clearly determine the role of interim PET/CT.

  15. Live (Rose-bengal stained) foraminifera from deep-sea anoxic salt brine in the Eastern Mediterranean: toward understanding limit of life for single-celled eukaryotes (foraminifera) (United States)

    Kitazato, H.; Ohkawara, N.; Iwasaki, A.; Nomaki, H.; Akoumianaki, I.; Tokuyama, H.


    What is a limit of life for the eukaryotes? Eukaryotes are thought to adapt and evolve under oxic environmental conditions. Recently, there are many exceptions for this hypothesis, as many eukaryotes including metazoan groups are found in anoxic environmental conditions. We found many rose-bengal stained foraminifera from a deep-hypersaline anoxic basin (DHAB) in the eastern Mediterranean. During KH06-04 cruise, we conducted oceanographic research at Medée Lake, the largest DHAB, that is located 100km southwest of Crete Island in the eastern Mediterranean. The lake situates at 2920m in water depth. Depth of saline water is 120m in maximum. Both water and sediment samplings were carried out both with Niskin bottles and multiple corer attached to camera watching sampling system at three sites, inside of the lake (CS), the edge of the lake (OMS) and the normal deep-sea floor (RS). Temperature, salinity, and dissolved oxygen concentrations at central saline lake are 15.27 oC, 328PSU, and 0.0 ml/L, respectively. Strong smell of hydrogen sulfide was detected from the lake sediment. Subsamples were conducted for multiple core samples using 3 subcores(φ 2.9cm) from each core tube (φ 8.2cm). Sediment samples were fixed with 4% formalin Rose Bengal solution on board. In laboratory, samples were washed with 32μm sieve. Rose Bengal stained specimens were picked under binocular stereomicroscope (Zeiss Stemi SV11) for surface 0.5cm layer, and identified with inverted microscope (Nikon ECLIPSE TE300). In total, 26 species belonging to 9 genera were identified from three sites. Six species belonging to two genera were identified in the center of the salt brine. Only a few species are common among three sites, even though the numbers of common species were 10 between OMS and RS sites. In DHAB, spherical organic-walled species, such as allogromiid and psammosphaerid, are dominant. In contrast, tube-like chitinous foraminifera, such as Resigella, Conicotheca and Nodellum, are

  16. Variable speed limits control for freeway based on cell transmission model%基于元胞传输模型的高速公路可变限速控制

    Institute of Scientific and Technical Information of China (English)

    马明辉; 杨庆芳; 梁士栋


    In order to solve congestion problem on freeway during peak period ,which leads to increase of vehicle delays ,and drop of service level ,an optimization method was proposed for bottleneck re‐gion on freeway mainline based on cell transmission model .Variable speed limits control factors and cell transmission model were combined to describe real‐time traffic flow on freeway .Further ,the op‐timization variable speed limits control model at bottleneck region of freeway was formulated with the objective of improving traffic efficiency and decreasing vehicle delays .T he test results show that opti‐mization variable speed limits control method proposed could improve traffic operation efficiency and traffic order ,especially during congestion hours .%针对高速公路交通拥挤、整体服务水平降低、车辆延误增加等问题,提出了一种基于元胞传输模型的高速公路瓶颈区域可变限速控制方法。将可变限速控制方法同元胞传输模型进行融合,使其对限速条件下高速公路交通流变化进行描述,并以提高通行效率和缩短车辆平均延误为控制目标,建立了高速公路瓶颈区域可变限速最优控制模型。实验证明:在高流量条件下,基于元胞传输模型的高速公路可变限速控制方法具有良好的控制效果,能够有效地提升高速公路整体服务水平。

  17. Passive immitance limiters

    Directory of Open Access Journals (Sweden)

    Filinyuk N. A.


    Full Text Available The paper presents quadripole R, L, C immittance limiters, in which output immittance to the certain value depends on the input immittance. A classification of immittance limiters is given. Basic parameters are considered: low and high levels of output immittance limiters; low and high values of input immittance, corresponding to low and high levels of limitation, accordingly; range of possible values of output immittance; steepness of immittance limiters; time of wearing-out (or delay; high and low cutoff frequencies; central working frequency; frequency band; relative range of working frequencies; non-linearity coefficient. The authors have designed passive R-, L-, C-limiters with possibility of limitation from above and from below. The influence of the input parasitic immittances on the immittance transfer characteristic is evaluated. In most cases parasite immittance does not influence the considered devices, including R-limiters «from above» with the input quality factor of QR(Linp=0,1…0,2 and L-limiters «from above» with high-quality input circuits with QL(Rinp>2. The analysis also shows that high-qualitiy circuits with QN(RinpN>3 should be used in C-limiters with input parasitic immittances, while at parasitic immittance of the limiting element low-quality circuits with QN(RiN>0,2 should be selected.

  18. Fundamental Limits to Cellular Sensing (United States)

    ten Wolde, Pieter Rein; Becker, Nils B.; Ouldridge, Thomas E.; Mugler, Andrew


    In recent years experiments have demonstrated that living cells can measure low chemical concentrations with high precision, and much progress has been made in understanding what sets the fundamental limit to the precision of chemical sensing. Chemical concentration measurements start with the binding of ligand molecules to receptor proteins, which is an inherently noisy process, especially at low concentrations. The signaling networks that transmit the information on the ligand concentration from the receptors into the cell have to filter this receptor input noise as much as possible. These networks, however, are also intrinsically stochastic in nature, which means that they will also add noise to the transmitted signal. In this review, we will first discuss how the diffusive transport and binding of ligand to the receptor sets the receptor correlation time, which is the timescale over which fluctuations in the state of the receptor, arising from the stochastic receptor-ligand binding, decay. We then describe how downstream signaling pathways integrate these receptor-state fluctuations, and how the number of receptors, the receptor correlation time, and the effective integration time set by the downstream network, together impose a fundamental limit on the precision of sensing. We then discuss how cells can remove the receptor input noise while simultaneously suppressing the intrinsic noise in the signaling network. We describe why this mechanism of time integration requires three classes (groups) of resources—receptors and their integration time, readout molecules, energy—and how each resource class sets a fundamental sensing limit. We also briefly discuss the scheme of maximum-likelihood estimation, the role of receptor cooperativity, and how cellular copy protocols differ from canonical copy protocols typically considered in the computational literature, explaining why cellular sensing systems can never reach the Landauer limit on the optimal trade

  19. In vivo erythrocyte micronucleus assay III. Validation and regulatory acceptance of automated scoring and the use of rat peripheral blood reticulocytes, with discussion of non-hematopoietic target cells and a single dose-level limit test. (United States)

    Hayashi, Makoto; MacGregor, James T; Gatehouse, David G; Blakey, David H; Dertinger, Stephen D; Abramsson-Zetterberg, Lilianne; Krishna, Gopala; Morita, Takeshi; Russo, Antonella; Asano, Norihide; Suzuki, Hiroshi; Ohyama, Wakako; Gibson, Dave


    , but a consensus regarding acceptability for regulatory purposes could not be reached at that time. Subsequent validation efforts, combined with accumulated published data, demonstrate that blood-derived reticulocytes from rats as well as mice are acceptable when young reticulocytes are analyzed under proper assay protocol and sample size. The working group reviewed the results of micronucleus assays using target cells/tissues other than hematopoietic cells. We also discussed the relevance of the liver micronucleus assay using young rats, and the importance of understanding the maturation of enzyme systems involved in the processes of metabolic activation in the liver of young rats. Although the consensus of the group was that the more information with regard to the metabolic capabilities of young rats would be useful, the published literature shows that young rats have sufficient metabolic capacity for the purposes of this assay. The use of young rats as a model for detecting MN induction in the liver offers a good alternative methodology to the use of partial hepatectomy or mitogenic stimulation. Additional data obtained from colon and skin MN models have been integrated into the data bases, enhancing confidence in the utility of these models. A fourth topic discussed by the working group was the regulatory acceptance of the single-dose-level assay. There was no consensus regarding the acceptability of a single dose level protocol when dose-limiting toxicity occurs. The use of a single dose level can lead to problems in data interpretation or to the loss of animals due to unexpected toxicity, making it necessary to repeat the study with additional doses. A limit test at a single dose level is currently accepted when toxicity is not dose-limiting.

  20. Key role of mast cells and their major secretory products in inflammatory bowel disease

    Institute of Scientific and Technical Information of China (English)

    Shao-Heng He


    Hirtoncally, mast cells were known as a key cell type involved in type I hypersensitivity Until last two decades, this cell type was recognized to be widely involved in a number of non-allergic diseases including inflammatory bowel disease (IBD). Markedly increased numbers of mast cells were observed in the mucosa of the iieum and colon of patients with IBD, which was accompanied by great changes of the content in mart cells such as dramatically increaed expression of TNFα, IL-16 and substance P.The evidence of mast cell degranulation was found in the wall of intestine from patients with IBD with immunohistochemistry technique. The highly elevated histamine and tryptase levels were detected in mucosa of petienta with IBD, strongly suggesting that mast cell degranulation is involved in the pathogenesis of IBD.However, Iittle is known of the actions of histamine, tryptase,chymase and carboxypeptidase in IBD. Over the lart decade,heparin has been used to treat IBD in clinical practice. The low molecular weight heparin (LMWH) was effective as adjuvant therapy, and the petienis showed good clinical and laberatory respense with no senous advere effectd. The roles of PGD2, LTC4, PAF and mast cell cytokines in IBD were also discussed. Recently, a series of experiments with dispersed colon mast cells suggested there should be at least two pathways in man for mast colls to amplify their own activationdegranulation signals in an autocrine or paracrine mannec.The hypethesis is that mast cell secretogogues induce mart cell degranulation, release histamine, then stimulate the adjacent mast cells or positively feedback to further stimulate its host mast cells through H1 recepton.Whereas released tryptase acts similarly to hirtamine, but activates mart cells through its receptor PAR-2. The connections between current anti-IBD therapies or potential therapies for IBD with mast cells were discussed, implicating further that mast cell is a key cell type that is involved in the

  1. Power limits for microbial life

    Directory of Open Access Journals (Sweden)

    Doug eLaRowe


    Full Text Available To better understand the origin, evolution and extent of life, we seek to determine the minimum flux of energy needed for organisms to remain viable. Despite the difficulties associated with direct measurement of the power limits for life, it is possible to use existing data and models to constrain the minimum flux of energy required to sustain microorganisms. Here, a we apply a bioenergetic model to a well characterized marine sedimentary environment in order to quantify the amount of power organisms use in an ultralow-energy setting. In particular, we show a direct link between power consumption in this environment and the amount of biomass (cells cm-3 found in it. The power supply resulting from the aerobic degradation of particular organic carbon (POC at IODP Site U1370 in the South Pacific Gyre is between ~ 10-12 and 10-16 W cm-3. The rates of POC degradation are calculated using a continuum model while Gibbs energies have been computed using geochemical data describing the sediment as a function of depth. Although laboratory-determined values of maintenance power do a poor job of representing the amount of biomass in U1370 sediments, the number of cells per cm-3 can be well-captured using a maintenance power, 190 zW cell-1, two orders of magnitude lower than the lowest value reported in the literature. In addition, we have combined cell counts and calculated power supplies to determine that, on average, the microorganisms at Site U1370 require 50 – 3500 zW cell-1, with most values under ~300 zW cell-1. Furthermore, we carried out an analysis of the absolute minimum power requirement for a single cell to remain viable to be on the order of 1 zW cell-1.

  2. Limitations on the Detection Rate of High-Risk HPV by Hybrid Capture 2 Methodology in High Grade Intraepithelial (HSIL or Atypical Squamous Cells-Cannot Exclude HSIL (ASC-H Cytological Lesions with Proved CIN2+

    Directory of Open Access Journals (Sweden)

    Jean-Christophe Noël


    Full Text Available Recent literature data suggest that the high-risk human papillomaviruses (HR-HPVs testing with several molecular techniques could be an alternative to cytology in the detection of cervical intraepithelial neoplasias of grade 2 or worse (CIN2+. However, any molecular techniques have its own limits and may give false negative results which must be clearly known before undertaking a primary HPV screening. This study aims to evaluate the performance of the high-risk HPV hybrid capture II detection kit (HCII which is considered as a “gold standard technique” in a series of 100 women having proved both cytological lesions of atypical squamous cells-cannot exclude an HSIL (ASC-H or high-grade squamous intraepithelial lesion (HSIL and histological lesions of CIN2+. The clinical sensitivity of HCII in women with a cytological diagnosis of ASC-H/HSIL and a diagnosis of CIN2+ is high but not absolute and estimated at 96% (95,6% and 100% of women with a diagnosis of CIN2/3 or invasive squamous cell carcinoma, resp.. These data although they are infrequent must be clearly referred before to start an HPV primary screening of CIN2+ especially with HCII methodology.

  3. Numerical Limit Analysis:

    DEFF Research Database (Denmark)

    Damkilde, Lars


    Limit State analysis has a long history and many prominent researchers have contributed. The theoretical foundation is based on the upper- and lower-bound theorems which give a very comprehensive and elegant formulation on complicated physical problems. In the pre-computer age Limit State analysis...

  4. Limitations to sharing entanglement

    CERN Document Server

    Kim, Jeong San; Sanders, Barry C


    We discuss limitations to sharing entanglement known as monogamy of entanglement. Our pedagogical approach commences with simple examples of limited entanglement sharing for pure three-qubit states and progresses to the more general case of mixed-state monogamy relations with multiple qudits.

  5. Limits to Inclusion (United States)

    Hansen, Janne Hedegaard


    In this article, I will argue that a theoretical identification of the limit to inclusion is needed in the conceptual identification of inclusion. On the one hand, inclusion is formulated as a vision that is, in principle, limitless. On the other hand, there seems to be an agreement that inclusion has a limit in the pedagogical practice. However,…

  6. Modeling Complex Time Limits

    Directory of Open Access Journals (Sweden)

    Oleg Svatos


    Full Text Available In this paper we analyze complexity of time limits we can find especially in regulated processes of public administration. First we review the most popular process modeling languages. There is defined an example scenario based on the current Czech legislature which is then captured in discussed process modeling languages. Analysis shows that the contemporary process modeling languages support capturing of the time limit only partially. This causes troubles to analysts and unnecessary complexity of the models. Upon unsatisfying results of the contemporary process modeling languages we analyze the complexity of the time limits in greater detail and outline lifecycles of a time limit using the multiple dynamic generalizations pattern. As an alternative to the popular process modeling languages there is presented PSD process modeling language, which supports the defined lifecycles of a time limit natively and therefore allows keeping the models simple and easy to understand.

  7. The Hugoniot Elastic Limit Decay Limit (United States)

    Billingsley, J. P.


    The Hugoniot Elastic Limit(HEL) precursor decay in shock loaded solids has been the subject of considerable experimental and theoretical investigation. Comparative evidence is presented to show that the elastic precursor wave particle velocity, UPHEL, for certain materials decays asymptotically with propagation distance to the DeBroglie velocity, V1, level. This is demonstrated for the following materials: iron, aluminum alloy 6061-T6, plexiglas(PMMA), nickel alloy(MAR-M200), and lithium flouride(LiF). The DeBroglie velocity, V1, equals h/2md, where h is Planck's Constant, m is the mass of one atom, and d is the closest distance between atoms. Thus a relationship has been established between a microscopically derived velocity, V1, and a macroscopically observed velocity, UPHEL.

  8. The limits on trypanosomatid morphological diversity.

    Directory of Open Access Journals (Sweden)

    Richard John Wheeler

    Full Text Available Cell shape is one, often overlooked, way in which protozoan parasites have adapted to a variety of host and vector environments and directional transmissions between these environments. Consequently, different parasite life cycle stages have characteristic morphologies. Trypanosomatid parasites are an excellent example of this in which large morphological variations between species and life cycle stage occur, despite sharing well-conserved cytoskeletal and membranous structures. Here, using previously published reports in the literature of the morphology of 248 isolates of trypanosomatid species from different hosts, we perform a meta-analysis of the occurrence and limits on morphological diversity of different classes of trypanosomatid morphology (trypomastigote, promastigote, etc. in the vertebrate bloodstream and invertebrate gut environments. We identified several limits on cell body length, cell body width and flagellum length diversity which can be interpreted as biomechanical limits on the capacity of the cell to attain particular dimensions. These limits differed for morphologies with and without a laterally attached flagellum which we suggest represent two morphological superclasses, the 'juxtaform' and 'liberform' superclasses. Further limits were identified consistent with a selective pressure from the mechanical properties of the vertebrate bloodstream environment; trypanosomatid size showed limits relative to host erythrocyte dimensions. This is the first comprehensive analysis of the limits of morphological diversity in any protozoan parasite, revealing the morphogenetic constraints and extrinsic selection pressures associated with the full diversity of trypanosomatid morphology.

  9. On noise limited cellular networks

    CERN Document Server

    Decreusefond, Laurent; Vu, Thanh-Tung


    This paper introduces a general theoretical framework to analyze noise limited networks. More precisely, we consider two homogenous Poisson point processes of base stations and users. General model of radio signal propagation and effect of fading are also considered. The main difference of our model with respect to other existing models is that a user connects to his best servers but not necessarily the closest one. We provide general formula for the outage probability. We study functionals related to the SNR as well as the sum of these functionals over all users per cell. For the latter, the expectation and bounds on the variance are obtained.

  10. HOME Rent Limits (United States)

    Department of Housing and Urban Development — In accordance with 24 CFR Part 92.252, HUD provides maximum HOME rent limits. The maximum HOME rents are the lesser of: The fair market rent for existing housing for...

  11. HUD Program Income Limits (United States)

    Department of Housing and Urban Development — Income limits used to determine the income eligibility of applicants for assistance under three programs authorized by the National Housing Act. These programs are...

  12. Limited Angle Tomography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Kyung; Cho, Min Kook; Kim, Seong Sik [Pusan National University, Busan (Korea, Republic of)


    In computed tomography (CT), many situations are restricted to obtain enough number of projections or views to avoid artifacts such as streaking and geometrical distortion in the reconstructed images. Speed of motion of an object to be imaged can limit the number of views. Cardiovascular imaging is a representative example. Size of an object can also limit the complete traverse motion or geometrical complexity can obscure to be imaged at certain range of angles. These situations are frequently met in industrial nondestructive testing and evaluation. Dental CT also suffers from similar situation because cervical spine causes less x-ray penetration from some directions such that the available information is not sufficient for standard reconstruction algorithms. The limited angle tomography is now greatly paid attention as a new genre in medical and industrial imaging, popularly known as digital tomosynthesis. In this study, we introduce a modified filtered backprojection method in limited angle tomography and demonstrate its application for the dental imaging.

  13. Limited Income and Resources (United States)

    U.S. Department of Health & Human Services — Information for those with limited income and resources (those who may qualify for or already have the Low Income Subsidy to lower their prescription drug coverage...

  14. ACA Federal Upper Limits (United States)

    U.S. Department of Health & Human Services — Affordable Care Act Federal Upper Limits (FUL) based on the weighted average of the most recently reported monthly average manufacturer price (AMP) for...

  15. Limited Denial of Participation (United States)

    Department of Housing and Urban Development — A Limited Denial of Participation (LDP) is an action taken by a HUD Field Office or the Deputy Assistant Secretary for Single Family (DASSF) or Multifamily (DASMF)...

  16. SIS - Annual Catch Limit (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Annual Catch Limit (ACL) dataset within the Species Information System (SIS) contains information and data related to management reference points and catch data.

  17. Biological measurement beyond the quantum limit

    CERN Document Server

    Taylor, Michael A; Daria, Vincent; Knittel, Joachi; Hage, Boris; Bachor, Hans-A; Bowen, Warwick P


    Quantum noise places a fundamental limit on the per photon sensitivity attainable in optical measurements. This limit is of particular importance in biological measurements, where the optical power must be constrained to avoid damage to the specimen. By using non-classically correlated light, we demonstrated that the quantum limit can be surpassed in biological measurements. Quantum enhanced microrheology was performed within yeast cells by tracking naturally occurring lipid granules with sensitivity 2.4 dB beyond the quantum noise limit. The viscoelastic properties of the cytoplasm could thereby be determined with a 64% improved measurement rate. This demonstration paves the way to apply quantum resources broadly in a biological context.

  18. Altruism and Reproductive Limitations

    Directory of Open Access Journals (Sweden)

    Carey J. Fitzgerald


    Full Text Available We examined how different types of reproductive limitations — functional (schizoid personality disorder and schizophrenia, physical (malnutrition, and sexual (bisexuality and homosexuality — influenced altruistic intentions toward hypothetical target individuals of differing degrees of relatedness (r = 0, .25, and .50. Participants were 312 undergraduate students who completed a questionnaire on altruism toward hypothetical friends, half-siblings, and siblings with these different types of reproductive limitations. Genetic relatedness and reproductive limitations did not influence altruistic decision-making when the cost of altruism was low but did as the cost of altruism increased, with participants being more likely to help a sibling over a half-sibling and a half-sibling over a friend. Participants also indicated they were more likely to help a healthy (control person over people with a reproductive limitation. Of the three types of reproductive limitations, functional limitations had the strongest effect on altruistic decision-making, indicating that people were less likely to help those who exhibit abnormal social behavior.

  19. Lactobacillus rhamnosus GR-1 Limits Escherichia coli-Induced Inflammatory Responses via Attenuating MyD88-Dependent and MyD88-Independent Pathway Activation in Bovine Endometrial Epithelial Cells. (United States)

    Liu, Mingchao; Wu, Qiong; Wang, Mengling; Fu, Yunhe; Wang, Jiufeng


    Intrauterine Escherichia coli infection after calving reduces fertility and causes major economic losses in the dairy industry. We investigated the protective effect of the probiotic Lactobacillus rhamnosus GR-1 on E. coli-induced cell damage and inflammation in primary bovine endometrial epithelial cells (BEECs). L. rhamnosus GR-1 reduced ultrastructure alterations and the percentage of BEECs apoptosis after E. coli challenge. Increased messenger RNA (mRNA) expression of immune response indicators, including pattern recognition receptors (toll-like receptor [TLR]2, TLR4, nucleotide-binding oligomerization domain [NOD]1, and NOD2), inflammasome proteins (NOD-like receptor family member pyrin domain-containing protein 3, apoptosis-associated speck-like protein, and caspase-1), TLR4 downstream adaptor molecules (myeloid differentiation antigen 88 [MyD88], toll-like receptor adaptor molecule 2 [TICAM2]), nuclear transcription factor kB (NF-kB), and the inflammatory cytokines tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8, IL-10, IL-18, and interferon (IFN)-β, was observed following E. coli challenge. However, these increases were attenuated by L. rhamnosus GR-1 pretreatment. Our data indicate that L. rhamnosus GR-1 ameliorates the E. coli-induced disruption of cellular ultrastructure, subsequently reducing the percentage of BEECs apoptosis and limiting inflammatory responses, partly via attenuation of MyD88-dependent and MyD88-independent pathway activation. Certain probiotics could potentially prevent postpartum uterine diseases in dairy cows, ultimately reducing the use of antibiotics.

  20. Fundamental Limits of Cooperation

    CERN Document Server

    Lozano, Angel; Andrews, Jeffrey G


    Cooperation is viewed as a key ingredient for interference management in wireless systems. This paper shows that cooperation has fundamental limitations. The main result is that even full cooperation between transmitters cannot in general change an interference-limited network to a noise-limited network. The key idea is that there exists a spectral efficiency upper bound that is independent of the transmit power. First, a spectral efficiency upper bound is established for systems that rely on pilot-assisted channel estimation; in this framework, cooperation is shown to be possible only within clusters of limited size, which are subject to out-of-cluster interference whose power scales with that of the in-cluster signals. Second, an upper bound is also shown to exist when cooperation is through noncoherent communication; thus, the spectral efficiency limitation is not a by-product of the reliance on pilot-assisted channel estimation. Consequently, existing literature that routinely assumes the high-power spect...

  1. The quantum geometric limit

    CERN Document Server

    Lloyd, Seth


    This letter analyzes the limits that quantum mechanics imposes on the accuracy to which spacetime geometry can be measured. By applying the fundamental physical bounds to measurement accuracy to ensembles of clocks and signals moving in curved spacetime -- e.g., the global positioning system -- I derive a covariant version of the quantum geometric limit: the total number of ticks of clocks and clicks of detectors that can be contained in a four volume of spacetime of radius r and temporal extent t is less than or equal to rt/\\pi x_P t_P, where x_P, t_P are the Planck length and time. The quantum geometric limit bounds the number of events or `ops' that can take place in a four-volume of spacetime: each event is associated with a Planck-scale area. Conversely, I show that if each quantum event is associated with such an area, then Einstein's equations must hold. The quantum geometric limit is consistent with and complementary to the holographic bound which limits the number of bits that can exist within a spat...

  2. Quantum-limit spectroscopy

    CERN Document Server

    Ficek, Zbigniew


    This book covers the main ideas, methods, and recent developments of quantum-limit optical spectroscopy and applications to quantum information, resolution spectroscopy, measurements beyond quantum limits, measurement of decoherence, and entanglement. Quantum-limit spectroscopy lies at the frontier of current experimental and theoretical techniques, and is one of the areas of atomic spectroscopy where the quantization of the field is essential to predict and interpret the existing experimental results. Currently, there is an increasing interest in quantum and precision spectroscopy both theoretically and experimentally, due to significant progress in trapping and cooling of single atoms and ions. This progress allows one to explore in the most intimate detail the ways in which light interacts with atoms and to measure spectral properties and quantum effects with high precision. Moreover, it allows one to perform subtle tests of quantum mechanics on the single atom and single photon scale which were hardly eve...

  3. Pushing the Photon Limit

    NARCIS (Netherlands)

    Wientjes, Emilie; Renger, Jan; Cogdell, Richard; Hulst, van Niek F.


    Nanoantennas are well-known for their effective role in fluorescence enhancement, both in excitation and emission. Enhancements of 3-4 orders of magnitude have been reported. Yet in practice, the photon emission is limited by saturation due to the time that a molecule spends in singlet and especi

  4. The Limits of Laughter. (United States)

    Mindess, Harvey


    Three incidents which elucidate the limits of laughter are described. Most persons enjoy humor as comic relief, but when humor strikes a blow at something they hold dear, they find it very hard to laugh. People are upset by an irreverent attitude toward things they hold in esteem. (RM)

  5. Tightening Home Purchase Limits

    Institute of Scientific and Technical Information of China (English)


    More Chinese cities will limit home purchase to cool the red-hot real estate market In June 2011,the average house price in 100 Chinese cities was 8,856 yuan ($1,373)per square meter.Of these cities,house prices in 75 of them increased

  6. Limitation of Auditors' Liability

    DEFF Research Database (Denmark)

    Werlauff, Erik; Foged-Ladefoged, Lise Kolding


    The article examines the question of whether rules on the limitation of auditors’ liability within the perspective of EU law are needed, and if so, which rules can provide an appropriate balance between the potential injured party’s interests and those of the auditing sector, including with respect...

  7. Limits of Software Reuse

    NARCIS (Netherlands)

    Holenderski, L.


    Software reuse is considered one of the main techniques to increasesoftware productivity. We present two simple mathematical argumentsthat show some theoretical limits of reuse. It turns out that the increase of productivity due to internal reuse is at most linear, farfrom the needed exponential gr

  8. Limits to responsible innovation

    NARCIS (Netherlands)

    de Hoop, E.; Pols, Auke; Romijn, Henny


    Responsible Innovation (RI) is a young field of research that has nevertheless had remarkable successes in dissemination within academic and political circles. However, there is relatively little awareness of its limits, blind spots and situations in which it cannot be used for actual innovation tra

  9. Cells

    Directory of Open Access Journals (Sweden)

    Zhao-Hui Jin


    Full Text Available As cancer stem cells (CSCs are postulated to play critical roles in cancer development, including metastasis and recurrence, CSC imaging would provide valuable information for cancer treatment and lead to CSC-targeted therapy. To assess the possibility of in vivo CSC targeting, we conducted basic studies on radioimmunotargeting of cancer cells positive for CD133, a CSC marker recognized in various cancers. Antibodies against CD133 were labeled with 125I, and their in vitro cell binding properties were tested. Using the same isotype IgG as a control, in vivo biodistribution of the labeled antibody retaining immunoreactivity was examined in mice bearing an HCT116 xenograft in which a population of the cancer cells expressed CD133. Intratumoral distribution of the labeled antibody was examined and compared to the CD133 expression pattern. The 125I-labeled anti-CD133 antibody showed a modest but significantly higher accumulation in the HCT116 xenograft compared to the control IgG. The intratumoral distribution of the labeled antibody mostly overlapped with the CD133 expression, whereas the control IgG was found in the area close to the necrotic tumor center. Our results indicate that noninvasive in vivo targeting of CSCs could be possible with radiolabeled antibodies against cell membrane markers.

  10. Telescopic limiting magnitudes (United States)

    Schaefer, Bradley E.


    The prediction of the magnitude of the faintest star visible through a telescope by a visual observer is a difficult problem in physiology. Many prediction formulas have been advanced over the years, but most do not even consider the magnification used. Here, the prediction algorithm problem is attacked with two complimentary approaches: (1) First, a theoretical algorithm was developed based on physiological data for the sensitivity of the eye. This algorithm also accounts for the transmission of the atmosphere and the telescope, the brightness of the sky, the color of the star, the age of the observer, the aperture, and the magnification. (2) Second, 314 observed values for the limiting magnitude were collected as a test of the formula. It is found that the formula does accurately predict the average observed limiting magnitudes under all conditions.

  11. Limitations Of Infrared Thermography (United States)

    Schott, John R.


    The state of the art of quantitative infrared thermography is addressed. We are asking more and more of thermography in the field of energy conservation. An energy and dollar conscious public wants to know how much heat is being lost and how much money can be saved by retrofit. Many mission oriented approaches have been developed to address these questions. However, many fundamental questions about how thermography works and how far its capabilities can be pushed have not been addressed. In addition, the theoretical and practical limits of doing benefit cost studies with thermography have not been seriously addressed. This paper discusses the limitations of the current technology and describes many unanswered but important questions facing the future use of thermography for quantitative heat loss analysis.

  12. Limits of proton conductivity. (United States)

    Kreuer, Klaus-Dieter; Wohlfarth, Andreas


    Parasitic current seems to be the cause for the "highest proton conductivity" of a material reported to date. Kreuer and Wohlfarth verify this hypothesis by measuring the conductivity of the same materials after preparing them in a different way. They further explain the limits of proton conductivity and comment on the problems of determining the conductivity of small objects (e.g., whiskers, see picture).

  13. Elastic limit of silicane. (United States)

    Peng, Qing; De, Suvranu


    Silicane is a fully hydrogenated silicene-a counterpart of graphene-having promising applications in hydrogen storage with capacities larger than 6 wt%. Knowledge of its elastic limit is critical in its applications as well as tailoring its electronic properties by strain. Here we investigate the mechanical response of silicane to various strains using first-principles calculations based on density functional theory. We illustrate that non-linear elastic behavior is prominent in two-dimensional nanomaterials as opposed to bulk materials. The elastic limits defined by ultimate tensile strains are 0.22, 0.28, and 0.25 along armchair, zigzag, and biaxial directions, respectively, an increase of 29%, 33%, and 24% respectively in reference to silicene. The in-plane stiffness and Poisson ratio are reduced by a factor of 16% and 26%, respectively. However, hydrogenation/dehydrogenation has little effect on its ultimate tensile strengths. We obtained high order elastic constants for a rigorous continuum description of the nonlinear elastic response. The limitation of second, third, fourth, and fifth order elastic constants are in the strain range of 0.02, 0.08, and 0.13, and 0.21, respectively. The pressure effect on the second order elastic constants and Poisson's ratio were predicted from the third order elastic constants. Our results could provide a safe guide for promising applications and strain-engineering the functions and properties of silicane monolayers.

  14. Limits to growth reconsidered. (United States)

    Hagen, E E


    In their book, ''The Limits of Growth,'' the authors conclude that through pollution, exhaustion of natural resources, and limits to the food supply, the world faces a catastrophic fall in population and in living standards by the middle of the 21st century. The authors fail to state, however, 1 centrally important assumption underlying their results, but which is present through their omission of the contrary assumption. In their model the continuing technical progress that has been a primary feature of the material world for the past 200 years suddenly ceases. The assumptions of the model presented in ''Limits of Growth'' are not the assumptions other analysts make - these are strangely unrealistic. These assumptions require closer examination. The assumption concerning population assumes that the sole determinants of birthrates are the level of industrialization and the food supply. This is not good demography, for demographers have long recognized that it may have been the decrease in death rates, not industrialization or the rise in income, that caused the decrease in birthrates. Furthermore, their theory that many of the natural resources are irreplacable is like the belief that the sun revolves around the earth. It is obvious and false. It neglects that part of technical process which includes invention of new natural resources. Technical advance is needed and the following are some of the problems that technical advance must overcome: 1) a need to discover how to increase food production progressively while preventing the runoff of chemical fertilizers from the soil into waterways, 2) the ''natural'' minerals on which until recently all have depended are ''biodegradable,'' 3) there is a similar problem with radioactive nuclear wastes; 4) energy must dissipate into heat; and 5) there is a need to hasten the decline in birthrates throughout the world. In conclusion, indefinitely continuing growth is not regarded as desirable only as possible.

  15. Limitations in forensic odontology

    Directory of Open Access Journals (Sweden)

    B Kavitha


    Full Text Available The concept of using dental evidence in forensic investigation has kindled so much interest in the recent past that forensic odontology is even suggested as the single positive identification method to solve certain forensic cases. In this process, the shortcomings in forensic odontology though few are overlooked. These discrepancies associated with various methods are to be weighed cautiously to make forensic odontology a more accurate, reliable, and reproducible investigatory science. In this paper, we present our understanding of the limitations in various methods employed in forensic odontology.

  16. Marketing with limited budget


    Smirnova, Daria


    The purpose of this research-based thesis was to get an idea how managers of two small resembling hotels of a specific region deal with marketing process with a limited budget. In addition, the aim of the thesis was to examine if hotel managers who were interviewed perceive marketing only in the way of ‘promotion’ rather than marketing research, marketing mix and marketing environment theories. It was also found out if hotel managers of those hotels consider marketing as a key to successful h...

  17. Drinking to the Limit

    DEFF Research Database (Denmark)

    Järvinen, Margaretha; Ellersgaard, Christoph Houman; Larsen, Anton Grau


    The aim of this article is to analyse social status differences in alcohol norms and practices seen from the perspective of ‘health governance’. Survey data on 1442 employees in a middle-sized, Danish firm are used to construct a Bourdieu-inspired social space, tied to four forms of capital: econ...... by the Danish National Health Board. Rather, this article identifies a relatively large group of high-positioned respondents balancing at the limits of risky drinking – or transgressing them, if measured by international standards....

  18. Orind Refractories Limited

    Institute of Scientific and Technical Information of China (English)

    Mr R. Mishra; Group Manging Director


    @@ "Sight can be acquired, Vision cannot". Orind Refractories Limited (ORIND), China was formed with this rare vision. At a time when the world was testing the tepid waters of China; Mr. Ravin Jhunjhunwala, Chairman of ORIND and the management of ORIND India had looked over the Great Wall to begin a journey of success. Incorported on 18th August 1994 with an initial investment of USD 5 million, ORL caters to the ever-demanding needs of the steel industry and beyond. Incidentally ORIND was the first wholly owned India company to set up base in China. Pesently, ORIND China has a 616 strong work force including 23 expatriates.

  19. Limitations of inclusive fitness. (United States)

    Allen, Benjamin; Nowak, Martin A; Wilson, Edward O


    Until recently, inclusive fitness has been widely accepted as a general method to explain the evolution of social behavior. Affirming and expanding earlier criticism, we demonstrate that inclusive fitness is instead a limited concept, which exists only for a small subset of evolutionary processes. Inclusive fitness assumes that personal fitness is the sum of additive components caused by individual actions. This assumption does not hold for the majority of evolutionary processes or scenarios. To sidestep this limitation, inclusive fitness theorists have proposed a method using linear regression. On the basis of this method, it is claimed that inclusive fitness theory (i) predicts the direction of allele frequency changes, (ii) reveals the reasons for these changes, (iii) is as general as natural selection, and (iv) provides a universal design principle for evolution. In this paper we evaluate these claims, and show that all of them are unfounded. If the objective is to analyze whether mutations that modify social behavior are favored or opposed by natural selection, then no aspect of inclusive fitness theory is needed.

  20. Smoothness of limit functors

    Indian Academy of Sciences (India)

    Benedictus Margaux


    Let be a scheme. Assume that we are given an action of the one dimensional split torus $\\mathbb{G}_{m,S}$ on a smooth affine -scheme $\\mathfrak{X}$. We consider the limit (also called attractor) subfunctor $\\mathfrak{X}_{}$ consisting of points whose orbit under the given action `admits a limit at 0’. We show that $\\mathfrak{X}_{}$ is representable by a smooth closed subscheme of $\\mathfrak{X}$. This result generalizes a theorem of Conrad et al. (Pseudo-reductive groups (2010) Cambridge Univ. Press) where the case when $\\mathfrak{X}$ is an affine smooth group and $\\mathbb{G}_{m,S}$ acts as a group automorphisms of $\\mathfrak{X}$ is considered. It also occurs as a special case of a recent result by Drinfeld on the action of $\\mathbb{G}_{m,S}$ on algebraic spaces (Proposition 1.4.20 of Drinfeld V, On algebraic spaces with an action of $\\mathfrak{G}_{m}$, preprint 2013) in case is of finite type over a field.

  1. (Limiting the greenhouse effect)

    Energy Technology Data Exchange (ETDEWEB)

    Rayner, S.


    Traveler attended the Dahlem Research Conference organized by the Freien Universitat, Berlin. The subject of the conference was Limiting the Greenhouse Effect: Options for Controlling Atmospheric CO{sub 2} Accumulation. Like all Dahlem workshops, this was a meeting of scientific experts, although the disciplines represented were broader than usual, ranging across anthropology, economics, international relations, forestry, engineering, and atmospheric chemistry. Participation by scientists from developing countries was limited. The conference was divided into four multidisciplinary working groups. Traveler acted as moderator for Group 3 which examined the question What knowledge is required to tackle the principal social and institutional barriers to reducing CO{sub 2} emissions'' The working rapporteur was Jesse Ausubel of Rockefeller University. Other working groups examined the economic costs, benefits, and technical feasibility of options to reduce emissions per unit of energy service; the options for reducing energy use per unit of GNP; and the significant of linkage between strategies to reduce CO{sub 2} emissions and other goals. Draft reports of the working groups are appended. Overall, the conference identified a number of important research needs in all four areas. It may prove particularly important in bringing the social and institutional research needs relevant to climate change closer to the forefront of the scientific and policy communities than hitherto.

  2. Limits to biofuels

    Directory of Open Access Journals (Sweden)

    Johansson S.


    Full Text Available Biofuel production is dependent upon agriculture and forestry systems, and the expectations of future biofuel potential are high. A study of the global food production and biofuel production from edible crops implies that biofuel produced from edible parts of crops lead to a global deficit of food. This is rather well known, which is why there is a strong urge to develop biofuel systems that make use of residues or products from forest to eliminate competition with food production. However, biofuel from agro-residues still depend upon the crop production system, and there are many parameters to deal with in order to investigate the sustainability of biofuel production. There is a theoretical limit to how much biofuel can be achieved globally from agro-residues and this amounts to approximately one third of todays’ use of fossil fuels in the transport sector. In reality this theoretical potential may be eliminated by the energy use in the biomass-conversion technologies and production systems, depending on what type of assessment method is used. By surveying existing studies on biofuel conversion the theoretical limit of biofuels from 2010 years’ agricultural production was found to be either non-existent due to energy consumption in the conversion process, or up to 2–6000TWh (biogas from residues and waste and ethanol from woody biomass in the more optimistic cases.

  3. Universal Limit on Communication

    CERN Document Server

    Bousso, Raphael


    I derive a universal upper bound on the capacity of any communication channel between two distant systems. The Holevo quantity, and hence the mutual information, is at most of order $E \\Delta t / \\hbar$, where $E$ the average energy of the signal, and $\\Delta t$ is the amount of time for which detectors operate. The bound does not depend on the size or mass of the emitting and receiving systems, nor on the nature of the signal. No restrictions on preparing and processing the signal are imposed. As an example, I consider the encoding of information in the transverse or angular position of a signal emitted and received by systems of arbitrarily large cross-section. In the limit of a large message space, quantum effects become important even if individual signals are classical, and the bound is upheld.

  4. Clinical limitations of Invisalign. (United States)

    Phan, Xiem; Ling, Paul H


    Adult patients seeking orthodontic treatment are increasingly motivated by esthetic considerations. The majority of these patients reject wearing labial fixed appliances and are looking instead to more esthetic treatment options, including lingual orthodontics and Invisalign appliances. Since Align Technology introduced the Invisalign appliance in 1999 in an extensive public campaign, the appliance has gained tremendous attention from adult patients and dental professionals. The transparency of the Invisalign appliance enhances its esthetic appeal for those adult patients who are averse to wearing conventional labial fixed orthodontic appliances. Although guidelines about the types of malocclusions that this technique can treat exist, few clinical studies have assessed the effectiveness of the appliance. A few recent studies have outlined some of the limitations associated with this technique that clinicians should recognize early before choosing treatment options.

  5. The Limits to Relevance (United States)

    Averill, M.; Briggle, A.


    Science policy and knowledge production lately have taken a pragmatic turn. Funding agencies increasingly are requiring scientists to explain the relevance of their work to society. This stems in part from mounting critiques of the "linear model" of knowledge production in which scientists operating according to their own interests or disciplinary standards are presumed to automatically produce knowledge that is of relevance outside of their narrow communities. Many contend that funded scientific research should be linked more directly to societal goals, which implies a shift in the kind of research that will be funded. While both authors support the concept of useful science, we question the exact meaning of "relevance" and the wisdom of allowing it to control research agendas. We hope to contribute to the conversation by thinking more critically about the meaning and limits of the term "relevance" and the trade-offs implicit in a narrow utilitarian approach. The paper will consider which interests tend to be privileged by an emphasis on relevance and address issues such as whose goals ought to be pursued and why, and who gets to decide. We will consider how relevance, narrowly construed, may actually limit the ultimate utility of scientific research. The paper also will reflect on the worthiness of research goals themselves and their relationship to a broader view of what it means to be human and to live in society. Just as there is more to being human than the pragmatic demands of daily life, there is more at issue with knowledge production than finding the most efficient ways to satisfy consumer preferences or fix near-term policy problems. We will conclude by calling for a balanced approach to funding research that addresses society's most pressing needs but also supports innovative research with less immediately apparent application.

  6. Neurotoxic injury pathways in differentiated mouse motor neuron–neuroblastoma hybrid (NSC-34D) cells in vitro—Limited effect of riluzole on thapsigargin, but not staurosporine, hydrogen peroxide and homocysteine neurotoxicity

    Energy Technology Data Exchange (ETDEWEB)

    Hemendinger, Richelle A., E-mail: [ALS Translational Neuroscience Laboratory, Carolinas Medical Center, Charlotte, NC 28203 (United States); Carolinas Neuromuscular/ALS-MDA Center, Department of Neurology, Carolinas Medical Center, Charlotte, NC 28203 (United States); Armstrong, Edward J. [ALS Translational Neuroscience Laboratory, Carolinas Medical Center, Charlotte, NC 28203 (United States); Carolinas Neuromuscular/ALS-MDA Center, Department of Neurology, Carolinas Medical Center, Charlotte, NC 28203 (United States); Radio, Nick [ThermoScientific, Pittsburgh, PA (United States); Brooks, Benjamin Rix [ALS Translational Neuroscience Laboratory, Carolinas Medical Center, Charlotte, NC 28203 (United States); Carolinas Neuromuscular/ALS-MDA Center, Department of Neurology, Carolinas Medical Center, Charlotte, NC 28203 (United States); University of North Carolina School of Medicine-Charlotte Campus (United States)


    The neuroblastoma–spinal motor neuron fusion cell line, NSC-34, in its differentiated form, NSC-34D, permits examining the effects of riluzole, a proven treatment for amyotrophic lateral sclerosis (ALS) on cell death induction by staurosporine (STS), thapsigargin (Thaps), hydrogen peroxide (H{sub 2}O{sub 2}) and homocysteine (HCy). These neurotoxins, applied exogenously, have mechanisms of action related to the various proposed molecular pathogenetic pathways in ALS and are differentiated from endogenous cell death that is associated with cytoplasmic aggregate formation in motor neurons. Nuclear morphology, caspase-3/7 activation and high content imaging were used to assess toxicity of these neurotoxins with and without co-treatment with riluzole, a benzothiazole compound with multiple pharmacological actions. STS was the most potent neurotoxin at killing NSC-34D cells with a toxic concentration at which 50% of maximal cell death is achieved (TC{sub 50} = 0.01 μM), followed by Thaps (TC{sub 50} = 0.9 μM) and H{sub 2}O{sub 2} (TC{sub 50} = 15 μM) with HCy requiring higher concentrations to kill at the same level (TC{sub 50} = 2200 μM). Riluzole provided neurorescue with a 20% absolute reduction (47.6% relative reduction) in apoptotic cell death against Thaps-induced NSC-34D cell (p ≤ 0.05), but had no effect on STS-, H{sub 2}O{sub 2}- and HCy-induced NSC-34D cell death. This effect of riluzole on Thaps induction of cell death was independent of caspase-3/7 activation. Riluzole mitigated a toxin that can cause intracellular calcium dysregulation associated with endoplasmic reticulum (ER) stress but not toxins associated with other cell death mechanisms. -- Highlights: ► Calcium-dependent neurotoxins are potent cell death inducers in NSC-34D cells. ► Riluzole provides neurorescue against Thaps-induced NSC-34D cell death. ► Riluzole had no effect on neurotoxicity by STS, H{sub 2}O{sub 2} and Hcy. ► Riluzole reduces NSC-34D cell death independent of

  7. Charter Halibut Limited Access Program (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This limited access system limits the number of charter vessels that may participate in the guided sport fishery for halibut in area 2C and 3A. NMFS issues a charter...

  8. CFO of CNOOC Limited Changed

    Institute of Scientific and Technical Information of China (English)


    @@ CNOOC Limited announced on December 24 that Yang Hua, Senior Vice President of CNOOC Limited and President of CNOOC International Limied will succeed Dr.Mark Qiu as Chief Financial Officer effective on January 1,2005.

  9. Intercell Interference Coordination through Limited Feedback

    Directory of Open Access Journals (Sweden)

    Lingjia Liu


    Full Text Available We consider the applications of multicell transmission schemes to the downlink of future wireless communication networks. A multicell multiple-input multiple output-(MIMOs based scheme with limited coordination among neighboring base stations (BSs is proposed to effectively combat the intercell interference by taking advantage of the degreesoffreedom in the spatial domain. In this scheme, mobile users are required to feedback channel-related information to both serving base station and interfering base station. Furthermore, a chordal distance-based compression scheme is introduced to reduce the feedback overhead. The performance of the proposed scheme is investigated through theoretical analysis as well as system level simulations. Both results suggest that the so-called “intercell interference coordination through limited feedback” scheme is a very good candidate for improving the cell-edge user throughput as well as the average cell throughput of the future wireless communication networks.

  10. Practical roadmap and limits to nanostructured photovoltaics. (United States)

    Lunt, Richard R; Osedach, Timothy P; Brown, Patrick R; Rowehl, Jill A; Bulović, Vladimir


    The significant research interest in the engineering of photovoltaic (PV) structures at the nanoscale is directed toward enabling reductions in PV module fabrication and installation costs as well as improving cell power conversion efficiency (PCE). With the emergence of a multitude of nanostructured photovoltaic (nano-PV) device architectures, the question has arisen of where both the practical and the fundamental limits of performance reside in these new systems. Here, the former is addressed a posteriori. The specific challenges associated with improving the electrical power conversion efficiency of various nano-PV technologies are discussed and several approaches to reduce their thermal losses beyond the single bandgap limit are reviewed. Critical considerations related to the module lifetime and cost that are unique to nano-PV architectures are also addressed. The analysis suggests that a practical single-junction laboratory power conversion efficiency limit of 17% and a two-cell tandem power conversion efficiency limit of 24% are possible for nano-PVs, which, when combined with operating lifetimes of 10 to 15 years, could position them as a transformational technology for solar energy markets.

  11. Fuel cells: A survey (United States)

    Crowe, B. J.


    A survey of fuel cell technology and applications is presented. The operating principles, performance capabilities, and limitations of fuel cells are discussed. Diagrams of fuel cell construction and operating characteristics are provided. Photographs of typical installations are included.

  12. Material limitations on the detection limit in refractometry

    DEFF Research Database (Denmark)

    Skafte-Pedersen, Peder; Nunes, Pedro; Xiao, Sanshui


    We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors...... and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a bio-liquid environment, such as a water buffer. In the transparency window (λ ≳ 1100 nm) of silicon...... the detection limit becomes almost independent on the filling fraction, while in the visible, the detection limit depends strongly on the filling fraction because the silicon absorbs strongly....

  13. Material Limitations on the Detection Limit in Refractometry

    Directory of Open Access Journals (Sweden)

    Niels Asger Mortensen


    Full Text Available We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a bio-liquid environment, such as a water buffer. In the transparency window (λ ≳ 1100 nm of silicon the detection limit becomes almost independent on the filling fraction, while in the visible, the detection limit depends strongly on the filling fraction because the silicon absorbs strongly.

  14. Material limitations on the detection limit in refractometry. (United States)

    Skafte-Pedersen, Peder; Nunes, Pedro S; Xiao, Sanshui; Mortensen, Niels Asger


    We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η, with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a bio-liquid environment, such as a water buffer. In the transparency window (λ ≳ 1100 nm) of silicon the detection limit becomes almost independent on the filling fraction, while in the visible, the detection limit depends strongly on the filling fraction because the silicon absorbs strongly.

  15. Material Limitations on the Detection Limit in Refractometry

    CERN Document Server

    Skafte-Pedersen, Peder; Xiao, Sanshui; Mortensen, Niels Asger; 10.3390/s91108382


    We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min{Dn} > eta with n+i*eta being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in a bio-liquid environment, such as a water buffer. In the transparency window of silicon the detection limit becomes almost independent on the filling fraction, while in the visible, the detection limit depends strongly on the filling fraction because silicon absorbs strongly.

  16. Material Limitations on the Detection Limit in Refractometry


    Niels Asger Mortensen; Sanshui Xiao; Peder Skafte-Pedersen; Nunes, Pedro S.


    We discuss the detection limit for refractometric sensors relying on high-Q optical cavities and show that the ultimate classical detection limit is given by min {Δn} ≳ η, with n + iη being the complex refractive index of the material under refractometric investigation. Taking finite Q factors and filling fractions into account, the detection limit declines. As an example we discuss the fundamental limits of silicon-based high-Q resonators, such as photonic crystal resonators, for sensing in ...

  17. Mast cell in enterocolitis associated with Hirschsprung disease%肥大细胞检测在先天性巨结肠小肠结肠炎中的临床意义

    Institute of Scientific and Technical Information of China (English)

    沈涤华; 施诚仁; 周莹; 余世耀; 吴燕; 严文波; 孙莲萍


    目的 探讨肥大细胞在先天性巨结肠小肠结肠炎发病机制的作用,为临床治疗提供依据.方法 2004年5月~2006年5月在上海交通大学医学院附属新华医院行先天性巨结肠根治术中切除的狭窄段、移行段和扩张段肠管黏膜层标本,共30例.男23例,女7例,年龄1个月~7岁,平均1.2岁.短段型5例,普通型18例,长段型6例,全结肠型1例.根据术前有无小肠结肠炎临床症状将患儿分为巨结肠肠炎组(n=12)和非肠炎组(n=18).肥大细胞采用甲苯胺蓝染色和免疫组织化学染色(chymase)染色.结果 巨结肠肠炎组狭窄段、移行段和扩张段肥大细胞在黏膜,黏膜下及扩张的血管周围聚集,脱颗粒现象明显.非肠炎组结肠组织中肥大细胞在黏膜下,黏膜明显减少,脱颗粒现象轻微.结论 肥大细胞在肠炎的发生中起一定的作用,采用肥大细胞抑制剂是一种新的临床治疗先天性巨结肠小肠结肠炎途径.%Objective To assess the role of mast cell and Hirschsprung's disease(HD)associated enterocolitis.Methods We studied 30 patients(23 boys and 7 girls)with HD admitted into our hospital between May 2004 and May 2006.There were 5 short-segment,18 common type,6 long-segment type and 1 total colon type HD. The patients were divided into enterocolitis group(n=12)and non-enterocolitis group(n=18).The mast cells were irnmunostained with toluidine blue and chymase.Results The dilated vessels and the mast cells with degranulation were localized in mucosal and sub-mucosal layers in the enterocolitis group.In the non-enterocolitis group,the mast cells were mainly in submucosallayer and to less extent in the mucosal layer with minimal degranulation.Conclusions These results suggest that mast cells may be involved in the pathogenesis of Hischsprung's diseaseassociated enterocolitis.

  18. Why Serological Responses during Cystitis are Limited

    Directory of Open Access Journals (Sweden)

    Hae Woong Choi


    Full Text Available The high frequency of urinary tract infections (UTIs, some of which appear to be endogenous relapses rather than reinfections by new isolates, point to defects in the host’s memory immune response. It has been known for many decades that, whereas kidney infections evoked an antibody response to the infecting bacteria, infections limited to the bladder failed to do so. We have identified the existence of a broadly immunosuppressive transcriptional program associated with the bladder, but not the kidneys, during infection of the urinary tract that is dependent on bladder mast cells. This involves the localized secretion of IL-10 and results in the suppression of humoral immune responses in the bladder. Mast cell-mediated immune suppression could suggest a role for these cells in critically balancing the needs to clear infections with the imperative to prevent harmful immune reactions in the host.


    Institute of Scientific and Technical Information of China (English)

    郑仁圻; 余君岳; 等


    Based on fundamental arguments,the expressions for the decision limit and the detection limit both in the count domain and in the cout rate domain are derive4d.These expressions are found to be different from those shown in the existing literature.

  20. Welfare Dynamics under Time Limits


    Jeff Grogger; Charles Michalopoulos


    Among the most important changes brought about by the Personal Responsibility and Work Opportunity Reconciliation Act of 1996 (PRWORA) is the imposition of time limits. In this paper, we analyze a simple model in which a potential welfare recipient chooses how to allocate her time-limited endowment of benefits so as to maximize her expected lifetime utility. Not surprisingly, the model reveals that time limits provide an incentive for the consumer to conserve, or bank, her benefits. More inte...

  1. Glutamate antagonists limit tumor growth



    Neuronal progenitors and tumor cells possess propensity to proliferate and to migrate. Glutamate regulates proliferation and migration of neurons during development, but it is not known whether it influences proliferation and migration of tumor cells. We demonstrate that glutamate antagonists inhibit proliferation of human tumor cells. Colon adenocarcinoma, astrocytoma, and breast and lung carcinoma cells were most sensitive to the antiproliferative effect of the N...

  2. Limit cycles in quantum systems

    Energy Technology Data Exchange (ETDEWEB)

    Niemann, Patrick


    In this thesis we investigate Limit Cycles in Quantum Systems. Limit cycles are a renormalization group (RG) topology. When degrees of freedom are integrated out, the coupling constants flow periodically in a closed curve. The presence of limit cycles is restricted by the necessary condition of discrete scale invariance. A signature of discrete scale invariance and limit cycles is log-periodic behavior. The first part of this thesis is concerned with the study of limit cycles with the similarity renormalization group (SRG). Limit cycles are mainly investigated within conventional renormalization group frameworks, where degrees of freedom, which are larger than a given cutoff, are integrated out. In contrast, in the SRG potentials are unitarily transformed and thereby obtain a band-diagonal structure. The width of the band structure can be regarded as an effective cutoff. We investigate the appearance of limit cycles in the SRG evolution. Our aim is to extract signatures as well as the scaling factor of the limit cycle. We consider the 1/R{sup 2}-potential in a two-body system and a three-body system with large scattering lengths. Both systems display a limit cycle. Besides the frequently used kinetic energy generator we apply the exponential and the inverse generator. In the second part of this thesis, Limit Cycles at Finite Density, we examine the pole structure of the scattering amplitude for distinguishable fermions at zero temperature in the medium. Unequal masses and a filled Fermi sphere for each fermion species are considered. We focus on negative scattering lengths and the unitary limit. The properties of the three-body spectrum in the medium and implications for the phase structure of ultracold Fermi gases are discussed.

  3. LimitS - A system for limit state analysis and optimal material layout

    DEFF Research Database (Denmark)

    Damkilde, Lars; Krenk, Steen


    A system LimitS for limit state analysis and material optimization has been developed and implemented in a PC environment. The program is formulated in a general finite element format with stress-based elements. The solution method is based on the lower-bound theorem, where an optimal stress...... the statics and kinematics of the collapse mode are determined via the dual variables of the LP-problem. In LimitS the following element types are implemented: two- and three-dimensional beam elements; truss elements; triangular slab elements; and shear and stringer elements for plates with in-plane loading....... Examples of all three problem types are given including both limit state analysis and material optimization....

  4. Delving into Limits of Sequences (United States)

    Cory, Beth; Smith, Ken W.


    Limits are foundational to the central concepts of calculus. However, the authors' experiences with students and educational research abound with examples of students' misconceptions about limits and infinity. The authors wanted calculus students to understand, appreciate, and enjoy their first introduction to advanced mathematical thought. Thus,…

  5. Solubility limits on radionuclide dissolution

    Energy Technology Data Exchange (ETDEWEB)

    Kerrisk, J.F.


    This paper examines the effects of solubility in limiting dissolution rates of a number of important radionuclides from spent fuel and high-level waste. Two simple dissolution models were used for calculations that would be characteristics of a Yucca Mountain repository. A saturation-limited dissolution model, in which the water flowing through the repository is assumed to be saturated with each waste element, is very conservative in that it overestimates dissolution rates. A diffusion-limited dissolution model, in which element-dissolution rates are limited by diffusion of waste elements into water flowing past the waste, is more realistic, but it is subject to some uncertainty at this time. Dissolution