SOLO: a meiotic protein required for centromere cohesion, coorientation, and SMC1 localization in Drosophila melanogaster.

Science.gov (United States)

Yan, Rihui; Thomas, Sharon E; Tsai, Jui-He; Yamada, Yukihiro; McKee, Bruce D

2010-02-08

Sister chromatid cohesion is essential to maintain stable connections between homologues and sister chromatids during meiosis and to establish correct centromere orientation patterns on the meiosis I and II spindles. However, the meiotic cohesion apparatus in Drosophila melanogaster remains largely uncharacterized. We describe a novel protein, sisters on the loose (SOLO), which is essential for meiotic cohesion in Drosophila. In solo mutants, sister centromeres separate before prometaphase I, disrupting meiosis I centromere orientation and causing nondisjunction of both homologous and sister chromatids. Centromeric foci of the cohesin protein SMC1 are absent in solo mutants at all meiotic stages. SOLO and SMC1 colocalize to meiotic centromeres from early prophase I until anaphase II in wild-type males, but both proteins disappear prematurely at anaphase I in mutants for mei-S332, which encodes the Drosophila homologue of the cohesin protector protein shugoshin. The solo mutant phenotypes and the localization patterns of SOLO and SMC1 indicate that they function together to maintain sister chromatid cohesion in Drosophila meiosis.

Genome-wide mapping of sister chromatid exchange events in single yeast cells using Strand-seq

NARCIS (Netherlands)

Claussin, Clemence; Porubsky, David; Spierings, Diana C. J.; Halsema, Nancy; Rentas, Stefan; Guryev, Victor; Lansdorp, Peter M.; Chang, Michael

2017-01-01

Homologous recombination involving sister chromatids is the most accurate, and thus most frequently used, form of recombination-mediated DNA repair. Despite its importance, sister chromatid recombination is not easily studied because it does not result in a change in DNA sequence, making

Effect of borax on immune cell proliferation and sister chromatid exchange in human chromosomes.

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Pongsavee, Malinee

2009-10-30

Borax is used as a food additive. It becomes toxic when accumulated in the body. It causes vomiting, fatigue and renal failure. The heparinized blood samples from 40 healthy men were studied for the impact of borax toxicity on immune cell proliferation (lymphocyte proliferation) and sister chromatid exchange in human chromosomes. The MTT assay and Sister Chromatid Exchange (SCE) technic were used in this experiment with the borax concentrations of 0.1, 0.15, 0.2, 0.3 and 0.6 mg/ml. It showed that the immune cell proliferation (lymphocyte proliferation) was decreased when the concentrations of borax increased. The borax concentration of 0.6 mg/ml had the most effectiveness to the lymphocyte proliferation and had the highest cytotoxicity index (CI). The borax concentrations of 0.15, 0.2, 0.3 and 0.6 mg/ml significantly induced sister chromatid exchange in human chromosomes (P Borax had effects on immune cell proliferation (lymphocyte proliferation) and induced sister chromatid exchange in human chromosomes. Toxicity of borax may lead to cellular toxicity and genetic defect in human.

Effect of borax on immune cell proliferation and sister chromatid exchange in human chromosomes

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Pongsavee Malinee

2009-10-01

Full Text Available Abstract Background Borax is used as a food additive. It becomes toxic when accumulated in the body. It causes vomiting, fatigue and renal failure. Methods The heparinized blood samples from 40 healthy men were studied for the impact of borax toxicity on immune cell proliferation (lymphocyte proliferation and sister chromatid exchange in human chromosomes. The MTT assay and Sister Chromatid Exchange (SCE technic were used in this experiment with the borax concentrations of 0.1, 0.15, 0.2, 0.3 and 0.6 mg/ml. Results It showed that the immune cell proliferation (lymphocyte proliferation was decreased when the concentrations of borax increased. The borax concentration of 0.6 mg/ml had the most effectiveness to the lymphocyte proliferation and had the highest cytotoxicity index (CI. The borax concentrations of 0.15, 0.2, 0.3 and 0.6 mg/ml significantly induced sister chromatid exchange in human chromosomes (P Conclusion Borax had effects on immune cell proliferation (lymphocyte proliferation and induced sister chromatid exchange in human chromosomes. Toxicity of borax may lead to cellular toxicity and genetic defect in human.

The cohesion protein SOLO associates with SMC1 and is required for synapsis, recombination, homolog bias and cohesion and pairing of centromeres in Drosophila Meiosis.

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Yan, Rihui; McKee, Bruce D

2013-01-01

Cohesion between sister chromatids is mediated by cohesin and is essential for proper meiotic segregation of both sister chromatids and homologs. solo encodes a Drosophila meiosis-specific cohesion protein with no apparent sequence homology to cohesins that is required in male meiosis for centromere cohesion, proper orientation of sister centromeres and centromere enrichment of the cohesin subunit SMC1. In this study, we show that solo is involved in multiple aspects of meiosis in female Drosophila. Null mutations in solo caused the following phenotypes: 1) high frequencies of homolog and sister chromatid nondisjunction (NDJ) and sharply reduced frequencies of homolog exchange; 2) reduced transmission of a ring-X chromosome, an indicator of elevated frequencies of sister chromatid exchange (SCE); 3) premature loss of centromere pairing and cohesion during prophase I, as indicated by elevated foci counts of the centromere protein CID; 4) instability of the lateral elements (LE)s and central regions of synaptonemal complexes (SCs), as indicated by fragmented and spotty staining of the chromosome core/LE component SMC1 and the transverse filament protein C(3)G, respectively, at all stages of pachytene. SOLO and SMC1 are both enriched on centromeres throughout prophase I, co-align along the lateral elements of SCs and reciprocally co-immunoprecipitate from ovarian protein extracts. Our studies demonstrate that SOLO is closely associated with meiotic cohesin and required both for enrichment of cohesin on centromeres and stable assembly of cohesin into chromosome cores. These events underlie and are required for stable cohesion of centromeres, synapsis of homologous chromosomes, and a recombination mechanism that suppresses SCE to preferentially generate homolog crossovers (homolog bias). We propose that SOLO is a subunit of a specialized meiotic cohesin complex that mediates both centromeric and axial arm cohesion and promotes homolog bias as a component of chromosome

Sister chromatid exchange in peripheral blood lymphocytes as a ...

African Journals Online (AJOL)

Introduction: Sister chromatid exchanges (SCEs) can be induced by various genotoxic treatments, suggesting that SCEs refl ect a DNA repair process and it may be a good index for assessment of genomic instability. However, the occurrence of genetic instability and in particular, of spontaneous SCEs has been strongly ...

Effect of borax on immune cell proliferation and sister chromatid exchange in human chromosomes

OpenAIRE

Pongsavee Malinee

2009-01-01

Abstract Background Borax is used as a food additive. It becomes toxic when accumulated in the body. It causes vomiting, fatigue and renal failure. Methods The heparinized blood samples from 40 healthy men were studied for the impact of borax toxicity on immune cell proliferation (lymphocyte proliferation) and sister chromatid exchange in human chromosomes. The MTT assay and Sister Chromatid Exchange (SCE) technic were used in this experiment with the borax concentrations of 0.1, 0.15, 0.2, 0...

Mechanisms of sister chromatid recombination

International Nuclear Information System (INIS)

Nakai, Sayaka; Machida, Isamu; Tsuji, Satsuki

1985-01-01

Studies using T948 as a model system have been carried out aimed at elucidating the mechanism of sister chromatid recombination (SCR). Characterization of U.V. light- and x-ray-induced SCR, the relationiship between SCR induction and DNA repair using rad mutations, and the relationship between SCR induction and the time of cell division using cdc mutations are presented. It has been supposed that SCR is induced at the phase of S-G 2 following DNA replication, that postreplication break of DNA strands is strongly involved in the induction of SCR, and that induction type of SCR, i.e., conversion type or recombination type, is dependent upon the type of molecular damage of DNA. (Namekawa, K.)

Sister-chromatid exchanges in nuclear fuel workers

International Nuclear Information System (INIS)

Prabhavathi, P. Aruna; Fatima, Shehla K.; Padmavathi, P.; Kumari, C. Kusuma; Reddy, P.P.

1995-01-01

Peripheral blood lymphocyte cultures of 116 smokers and 80 non-smokers who were occupationally exposed to uranyl compounds were analysed for sister-chromatid exchanges (SCEs). Blood samples were collected from 59 non-smokers (control group I) and 47 smokers (control group II) who were not exposed to uranium for control data. A significant increase in SCEs was observed among both smokers and non-smokers exposed to uranyl compounds when compared to their respective controls. In controls, a significant increase in the frequency of SCEs was observed in smokers when compared to non-smokers

What are sister chromatid exchanges

International Nuclear Information System (INIS)

Evans, H.J.

1977-01-01

The development of new staining techniques to visualise sister chromatid exchange (SCE) in cells exposed to mutagens has led to a better understanding of the mechanisms involved in the formation of such exchanges. SCE are induced by a wide variety of different physical and chemical agents and their incidence provides a sensitive indicator of DNA damage in proliferating mammalian cells. It is shown that lesions which affect one or both strands of the DNA can result in the development of SCE, but only when damaged DNA undergoes replication. The nature of the lesions, the frequency and distribution of SEC in mammalian cells; the sensitivity of the cells to their induction by X-radiation, ultraviolet radiation and chemical mutagens, are discussed and possible mechanisms involved in the formation of SCE during replication considered. (Auth.)

Frequent and efficient use of the sister chromatid for DNA double-strand break repair during budding yeast meiosis.

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Tamara Goldfarb

2010-10-01

Full Text Available Recombination between homologous chromosomes of different parental origin (homologs is necessary for their accurate segregation during meiosis. It has been suggested that meiotic inter-homolog recombination is promoted by a barrier to inter-sister-chromatid recombination, imposed by meiosis-specific components of the chromosome axis. Consistent with this, measures of Holliday junction-containing recombination intermediates (joint molecules [JMs] show a strong bias towards inter-homolog and against inter-sister JMs. However, recombination between sister chromatids also has an important role in meiosis. The genomes of diploid organisms in natural populations are highly polymorphic for insertions and deletions, and meiotic double-strand breaks (DSBs that form within such polymorphic regions must be repaired by inter-sister recombination. Efforts to study inter-sister recombination during meiosis, in particular to determine recombination frequencies and mechanisms, have been constrained by the inability to monitor the products of inter-sister recombination. We present here molecular-level studies of inter-sister recombination during budding yeast meiosis. We examined events initiated by DSBs in regions that lack corresponding sequences on the homolog, and show that these DSBs are efficiently repaired by inter-sister recombination. This occurs with the same timing as inter-homolog recombination, but with reduced (2- to 3-fold yields of JMs. Loss of the meiotic-chromosome-axis-associated kinase Mek1 accelerates inter-sister DSB repair and markedly increases inter-sister JM frequencies. Furthermore, inter-sister JMs formed in mek1Δ mutants are preferentially lost, while inter-homolog JMs are maintained. These findings indicate that inter-sister recombination occurs frequently during budding yeast meiosis, with the possibility that up to one-third of all recombination events occur between sister chromatids. We suggest that a Mek1-dependent reduction in

A schedule to demonstrate radiation-induced sister chromatid exchanges in human lymphocytes

International Nuclear Information System (INIS)

Chaudhuri, J.P.

1982-01-01

The reciprocal interchange between the chromatids of a chromosome, termed sister chromatid exchange (SCE), is considered to be one of the most sensitive and accurate cytogenetic parameters and respond to toxic chemicals at very low doses. But the response of SCE to ionizing radiation is very poor. Human lymphocytes fail to give SCE response when irradiated at G 0 . Probably the primary lesions induced at G 0 do not remain available long enough to find expression as SCEs. Based on this assumption a schedule was developed using caffeine to demonstrate radiation induced SCEs. Following this schedule a dose-dependent increase in the frequency of radiation induced SCEs has been observed. (orig.)

Frequency of sister chromatid exchanges in lymphocyte cultures of human peripheral blood after the combined effect of γ-radiation and caffeine

International Nuclear Information System (INIS)

Nugis, V.Yu.; Pyatkin, E.K.

1986-01-01

Keeping of human peripheral blood lymphocytes, irradiated in vitro with 60 Co-γ-quanta at a dose of 3 Gy at G 0 phase, with caffeine of 16 and 160 μg/ml during cultivation with PHA had no appreciable influence on the fraquency of sister chromatid exchanges. A minor increase in the number of sister chromatid exchanges was only noted when nonirradiated and irradiated lymphocytes were cultured with 160 μg/ml caffeine

Photoreactivation of ultraviolet light-induced sister chromatid exchanges in potorous cells

International Nuclear Information System (INIS)

Ishizaki, K.; Nikaido, O.; Takebe, H.

1980-01-01

Exposure to visible light after UV-irradiation showed a remarkable effect on UV-induced sister chromatid exchanges (SCEs). After 6-h exposure to visible light (3 x 10 5 J/m 2 ), two-thirds of the UV-induced SCEs were prevented, confirming Kato's findings. (Nature 249, 552-3, 1974) Exposure to visible light before UV irradiation had no effect. This effect of visible light on UV-induced CSEs was temperature dependent, suggesting the presence of enzymatic photoreactivation. (author)

Regulation of the Drosophila Enhancer of split and invected-engrailed gene complexes by sister chromatid cohesion proteins.

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Cheri A Schaaf

2009-07-01

Full Text Available The cohesin protein complex was first recognized for holding sister chromatids together and ensuring proper chromosome segregation. Cohesin also regulates gene expression, but the mechanisms are unknown. Cohesin associates preferentially with active genes, and is generally absent from regions in which histone H3 is methylated by the Enhancer of zeste [E(z] Polycomb group silencing protein. Here we show that transcription is hypersensitive to cohesin levels in two exceptional cases where cohesin and the E(z-mediated histone methylation simultaneously coat the entire Enhancer of split and invected-engrailed gene complexes in cells derived from Drosophila central nervous system. These gene complexes are modestly transcribed, and produce seven of the twelve transcripts that increase the most with cohesin knockdown genome-wide. Cohesin mutations alter eye development in the same manner as increased Enhancer of split activity, suggesting that similar regulation occurs in vivo. We propose that cohesin helps restrain transcription of these gene complexes, and that deregulation of similarly cohesin-hypersensitive genes may underlie developmental deficits in Cornelia de Lange syndrome.

RPA Mediates Recruitment of MRX to Forks and Double-Strand Breaks to Hold Sister Chromatids Together.

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Seeber, Andrew; Hegnauer, Anna Maria; Hustedt, Nicole; Deshpande, Ishan; Poli, Jérôme; Eglinger, Jan; Pasero, Philippe; Gut, Heinz; Shinohara, Miki; Hopfner, Karl-Peter; Shimada, Kenji; Gasser, Susan M

2016-12-01

The Mre11-Rad50-Xrs2 (MRX) complex is related to SMC complexes that form rings capable of holding two distinct DNA strands together. MRX functions at stalled replication forks and double-strand breaks (DSBs). A mutation in the N-terminal OB fold of the 70 kDa subunit of yeast replication protein A, rfa1-t11, abrogates MRX recruitment to both types of DNA damage. The rfa1 mutation is functionally epistatic with loss of any of the MRX subunits for survival of replication fork stress or DSB recovery, although it does not compromise end-resection. High-resolution imaging shows that either the rfa1-t11 or the rad50Δ mutation lets stalled replication forks collapse and allows the separation not only of opposing ends but of sister chromatids at breaks. Given that cohesin loss does not provoke visible sister separation as long as the RPA-MRX contacts are intact, we conclude that MRX also serves as a structural linchpin holding sister chromatids together at breaks. Copyright © 2016 Elsevier Inc. All rights reserved.

Induction of sister chromatid exchange in the presence of gadolinium-DTPA and its reduction by dimethyl sulfoxide

International Nuclear Information System (INIS)

Yamazaki, Etsuo; Fukuda, Hozumi; Shibuya, Hitoshi; Matsubara, Sho

1996-01-01

The authors investigate the frequency of sister chromatid exchange (SCE) after the addition of gadolinium (Gd)-DTPA to venous blood samples. Venous blood was obtained from nonsmokers. Samples were incubated with Gd-DTPA alone or in combination with mitomycin C, cytarabine, and dimethyl sulfoxide (DMSO), and then evaluated for SCEs. The frequency of SCE increased with the concentration of Gd-DTPA and as each chemotherapeutic agent was added. Sister chromatid exchange frequencies were lower when the blood was treated with a combination of Gd-DTPA and DMSO compared with Gd-DTPA alone. The increase in frequency of SCE seen after the addition of Gd-DTPA was decreased by the addition of DMSO, indicating the production of hydroxyl radicals. The effect likely is dissociation-related. 14 refs., 6 tabs

A CO-FISH assay to assess sister chromatid segregation patterns in mitosis of mouse embryonic stem cells.

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Sauer, Stephan; Burkett, Sandra S; Lewandoski, Mark; Klar, Amar J S

2013-05-01

Sister chromatids contain identical DNA sequence but are chiral with respect to both their helical handedness and their replication history. Emerging evidence from various model organisms suggests that certain stem cells segregate sister chromatids nonrandomly to either maintain genome integrity or to bias cellular differentiation in asymmetric cell divisions. Conventional methods for tracing of old vs. newly synthesized DNA strands generally lack resolution for individual chromosomes and employ halogenated thymidine analogs with profound cytotoxic effects on rapidly dividing cells. Here, we present a modified chromosome orientation fluorescence in situ hybridization (CO-FISH) assay, where identification of individual chromosomes and their replication history is achieved in subsequent hybridization steps with chromosome-specific DNA probes and PNA telomere probes. Importantly, we tackle the issue of BrdU cytotoxicity and show that our method is compatible with normal mouse ES cell biology, unlike a recently published related protocol. Results from our CO-FISH assay show that mitotic segregation of mouse chromosome 7 is random in ES cells, which contrasts previously published results from our laboratory and settles a controversy. Our straightforward protocol represents a useful resource for future studies on chromatid segregation patterns of in vitro-cultured cells from distinct model organisms.

Possible mechanisms of chromosomal aberrations: VII. Comparative dynamics of sister chromatid disjunction and realization of radiation-induced chromosomal aberrations during mitosis

International Nuclear Information System (INIS)

Lebedeva, L.I.; Akhmamet'eva, E.M.

1994-01-01

An increase in radiation-induced chromosomal aberrations during c-metaphase sister chromatid disjunction was demonstrated in murine bone marrow cells exposed to a total γ-irradiation at 0.5 Gy. Caffeine (Cf) treatment during mitosis partially suppressed the chromatid disjunction rate and increased the number of radiation-induced aberrations in this mitosis. Nalidixic acid (NA) treatment of c-metaphase cells completely suppressed chromatid disjunction and the realization of induced aberrations. Topoisomerase 2 was assumed to be involved during mitosis in both processes

A proposal of a standardised nomenclature for terminal minute sister chromatid exchanges

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Máximo E. Drets

2006-01-01

Full Text Available We described spontaneous minute sister chromatid exchanges (SCE in telomeric regions of human and Chinese hamster ovary (CHO chromosomes more than 10 years ago. These structures, which we called t-SCE, were detected by means of highly precise quantitative microphotometrical scanning and computer graphic image analysis. Recently, several authors using the CO-FISH method also found small SCEs in telomeric regions and called them T-SCE. The use of different terms for designating the same phenomenon should be avoided. We propose ter SCE as a uniform nomenclature for minute telomeric SCEs.

Ultraviolet-induced formation of micronuclei and sister chromatid exchange in cultured fibroblasts of patients with cutaneous malignant melanoma

International Nuclear Information System (INIS)

Roser, M.; Boehm, A.O.; Oldigs, M.; Weichenthal, M.; Reimers, U.; Schmidt-Preuss, U.; Breitbart, E.W.; Ruediger, H.W.

1989-01-01

Genetically enhanced sensitivity to ultraviolet (UV) radiation may play an important role in the development of cutaneous malignant melanoma (CMM). This was studied in cultured fibroblasts of 26 CMM patients and controls by micronucleus (MN) test and sister chromatid exchange (SCE) after UV irradiation (375 J/m2). Sister chromatid exchange and MN formation were used as parameters to detect the UV-induced genotoxic damage in the individual cell strains. We found that the UV-induced level of MN was significantly increased in CMM patients (p = 0.0005), being most pronounced in the familial cases (p = 0.0001). Ultraviolet-induced SCE was also elevated in CMM patients (p = 0.001), but there was no difference between familial and nonfamilial cases. The present findings indicate that genetic predisposition contributes to the development of CMM in a subset of CMM patients and may be due to an enhanced susceptibility to UV light

Chiasmata promote monopolar attachment of sister chromatids and their co-segregation toward the proper pole during meiosis I.

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Yukinobu Hirose

2011-03-01

Full Text Available The chiasma is a structure that forms between a pair of homologous chromosomes by crossover recombination and physically links the homologous chromosomes during meiosis. Chiasmata are essential for the attachment of the homologous chromosomes to opposite spindle poles (bipolar attachment and their subsequent segregation to the opposite poles during meiosis I. However, the overall function of chiasmata during meiosis is not fully understood. Here, we show that chiasmata also play a crucial role in the attachment of sister chromatids to the same spindle pole and in their co-segregation during meiosis I in fission yeast. Analysis of cells lacking chiasmata and the cohesin protector Sgo1 showed that loss of chiasmata causes frequent bipolar attachment of sister chromatids during anaphase. Furthermore, high time-resolution analysis of centromere dynamics in various types of chiasmate and achiasmate cells, including those lacking the DNA replication checkpoint factor Mrc1 or the meiotic centromere protein Moa1, showed the following three outcomes: (i during the pre-anaphase stage, the bipolar attachment of sister chromatids occurs irrespective of chiasma formation; (ii the chiasma contributes to the elimination of the pre-anaphase bipolar attachment; and (iii when the bipolar attachment remains during anaphase, the chiasmata generate a bias toward the proper pole during poleward chromosome pulling that results in appropriate chromosome segregation. Based on these results, we propose that chiasmata play a pivotal role in the selection of proper attachments and provide a backup mechanism that promotes correct chromosome segregation when improper attachments remain during anaphase I.

The SUMO protease SENP1 is required for cohesion maintenance and mitotic arrest following spindle poison treatment

Energy Technology Data Exchange (ETDEWEB)

Era, Saho [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Abe, Takuya; Arakawa, Hiroshi [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Kobayashi, Shunsuke [Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Szakal, Barnabas [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy); Yoshikawa, Yusuke; Motegi, Akira; Takeda, Shunichi [Radiation Genetics, Graduate School of Medicine, Kyoto University, Yoshida-Konoe, Sakyo-ku, Kyoto 606-8501 (Japan); Branzei, Dana, E-mail: dana.branzei@ifom.eu [Fondazione IFOM, Istituto FIRC di Oncologia Molecolare, IFOM-IEO campus, Via Adamello 16, 20139 Milan (Italy)

2012-09-28

Highlights: Black-Right-Pointing-Pointer SENP1 knockout chicken DT40 cells are hypersensitive to spindle poisons. Black-Right-Pointing-Pointer Spindle poison treatment of SENP1{sup -/-} cells leads to increased mitotic slippage. Black-Right-Pointing-Pointer Mitotic slippage in SENP1{sup -/-} cells associates with apoptosis and endoreplication. Black-Right-Pointing-Pointer SENP1 counteracts sister chromatid separation during mitotic arrest. Black-Right-Pointing-Pointer Plk1-mediated cohesion down-regulation is involved in colcemid cytotoxicity. -- Abstract: SUMO conjugation is a reversible posttranslational modification that regulates protein function. SENP1 is one of the six SUMO-specific proteases present in vertebrate cells and its altered expression is observed in several carcinomas. To characterize SENP1 role in genome integrity, we generated Senp1 knockout chicken DT40 cells. SENP1{sup -/-} cells show normal proliferation, but are sensitive to spindle poisons. This hypersensitivity correlates with increased sister chromatid separation, mitotic slippage, and apoptosis. To test whether the cohesion defect had a causal relationship with the observed mitotic events, we restored the cohesive status of sister chromatids by introducing the TOP2{alpha}{sup +/-} mutation, which leads to increased catenation, or by inhibiting Plk1 and Aurora B kinases that promote cohesin release from chromosomes during prolonged mitotic arrest. Although TOP2{alpha} is SUMOylated during mitosis, the TOP2{alpha}{sup +/-} mutation had no obvious effect. By contrast, inhibition of Plk1 or Aurora B rescued the hypersensitivity of SENP1{sup -/-} cells to colcemid. In conclusion, we identify SENP1 as a novel factor required for mitotic arrest and cohesion maintenance during prolonged mitotic arrest induced by spindle poisons.

Mutagen-induced sister chromatid exchanges in xeroderma pigmentosum and normal lymphocytes

International Nuclear Information System (INIS)

Perry, P.E.; Jager, M.; Evans, H.J.

1978-01-01

The induction of sister chromatid exchanges (SCE), by ultra-violet irradiation and by three chemical mutagens that differ in the type of repair response that they elicit, has been compared in lymphocytes from a control and from an individual suffering from the DNA excision repair deficiency syndrome, xeroderma pigmentosum (XP). The XP lymphocytes were found to be more sensitive in terms of SCE response, not only to UV irradiation, but also to all of the chemicals studied. The results indicate that the abnormality of DNA repair in this XP patient is expressed not only in the defective excision of thymine dimers, or other UV photoproducts, but also in a reduced ability to repair other types of DNA lesion. (author)

Influence of irradiation at different stages of mitotic cycle upon production of sister chromatid exchanges in cultured Chinese hamster cells

International Nuclear Information System (INIS)

Antoshina, M.M.; Poryadkova, N.A.; Luchnik, N.V.

1982-01-01

Frequency of sister chromatid exchanges (SCE) and microexchanges in Chinese hamster cells has been studied by means of the method of differential staining of chromatids on irradiation at different stages of the mitotic cycle. It is shown that the irradiation enhances frequency of SCE and microexchanges if it is carried out before the end of DNA replication synthesis. Comparison of frequency depenedence of radiation-induced microexchanges and SCE at different stages of the mitotic cycle results in the conclusion that the microexchanges are none other than small SCE

Relationship of DNA repair to chromosome aberrations, sister-chromatid exchanges and survival during liquid-holding recovery in X-irradiated mammalian cells

International Nuclear Information System (INIS)

Fornace, A.J. Jr.; Nagasawa, H.; Little, J.B.

1980-01-01

The repair of X-ray-induced DNA single strand breaks and DNA-protein cross-links was investigated in stationary phase, contact-inhibited mouse cells by the alkaline-elution technique. Approx. 90% of X-ray-induced single strand breaks were rejoined during the first hour of repair, whereas most of the remaining breaks were rejoined more slowly during the next 5 h. At early repair times, the number of residual non-rejoined sungle strand breaks was approx. proportional to the X-ray dose. DNA-protein cross-links were removed at a slower rate (Tsub(1/2) approx. 10-12 h). Cells were held in stationary growth for various periods of time after irradiation before subculture at low density to score for colony survival (potentially lethal damage repair), chromosome aberrations in the first mitosis, and sister-chromatid exchanges in the second mitosis. Both cell killing and the frequency of chromosome aberrations decreased during the first several hours of recovery, reaching a minimum level by 6 h; this decrease correlated temporally with the repair of the slowly rejoining DNA-strand breaks. Relatively few sister-chromatid exchanges were observed when the cells were subcultured immediately after X-ray. The exchange frequency rose to maximum levels after a 4-h recovery interval, and returned to control levels after 12 h of recovery. The possible relationship of DNA repair to these changes in survival, chromosome aberrations, and sister-chromatid exchanges during liquid-holding recovery is discussed. (orig.)

Sister-chromatid exchange induced by X-ray of human lymphocytes and the effect of L-crysteine

International Nuclear Information System (INIS)

Abramovski, I.; Vorsanger, G.; Hirschhorn, K.

1978-01-01

A staining technique that detects sister-chromatid exchanges (SCEs) has been used to examine the response of human lymphocyte chromosomes to various dosages of X-irradiation. The SCE frequency was markedly increased following irradiation. However, the increase was of a significantly smaller magnitude when irradiation occurred in the presence of an antimutagenic agent. Scoring SCEs may provide a useful technique for assaying the mutagenic effects of environmental carcinogens as well as the protective effects of antimutagenic agents. (Auth.)

Separase Is Required for Homolog and Sister Disjunction during Drosophila melanogaster Male Meiosis, but Not for Biorientation of Sister Centromeres.

Science.gov (United States)

Blattner, Ariane C; Chaurasia, Soumya; McKee, Bruce D; Lehner, Christian F

2016-04-01

Spatially controlled release of sister chromatid cohesion during progression through the meiotic divisions is of paramount importance for error-free chromosome segregation during meiosis. Cohesion is mediated by the cohesin protein complex and cleavage of one of its subunits by the endoprotease separase removes cohesin first from chromosome arms during exit from meiosis I and later from the pericentromeric region during exit from meiosis II. At the onset of the meiotic divisions, cohesin has also been proposed to be present within the centromeric region for the unification of sister centromeres into a single functional entity, allowing bipolar orientation of paired homologs within the meiosis I spindle. Separase-mediated removal of centromeric cohesin during exit from meiosis I might explain sister centromere individualization which is essential for subsequent biorientation of sister centromeres during meiosis II. To characterize a potential involvement of separase in sister centromere individualization before meiosis II, we have studied meiosis in Drosophila melanogaster males where homologs are not paired in the canonical manner. Meiosis does not include meiotic recombination and synaptonemal complex formation in these males. Instead, an alternative homolog conjunction system keeps homologous chromosomes in pairs. Using independent strategies for spermatocyte-specific depletion of separase complex subunits in combination with time-lapse imaging, we demonstrate that separase is required for the inactivation of this alternative conjunction at anaphase I onset. Mutations that abolish alternative homolog conjunction therefore result in random segregation of univalents during meiosis I also after separase depletion. Interestingly, these univalents become bioriented during meiosis II, suggesting that sister centromere individualization before meiosis II does not require separase.

Sister chromatid exchange in children of Seventh-Day Adventists and matched controls.

Science.gov (United States)

Hermansen, R; Waksvik, H; Fønnebø, V

1991-03-01

The low risk of cancer in Seventh-Day Adventists (SDAs) has been suggested to be due to genetic selection. To investigate this claim we examined the sister chromatid exchange (SCE) frequency in peripheral blood lymphocytes in 16 SDA children in Tromsø, all aged 0.5-8 years and 16 controls matched for sex and age. In 12 of 16 pairs, the SDA children had a lower SCE frequency than the controls. The mean difference was 4.06 (95% confidence interval -17.02-8.89, P = 0.51). There was no sex difference, and no correlation between age and SCE frequency. The genetic starting point with regard to SCE frequency seems to be the same for SDA children and controls.

Sister chromatid exchange induced by X-irradiation of retinoblastoma lymphocytes

International Nuclear Information System (INIS)

Abramovsky-Kaplan, I.; Jones, I.S.

1984-01-01

Lymphocyte cultures were employed to assess the degree of spontaneous and induced chromosomal fragility in retinoblastoma. Sister chromatid exchange (SCEs) were scored in metaphases. Three unilateral, three bilateral, eleven family members and controls were studied. Retinoblastoma (RB) lymphocytes did not exhibit increased spontaneous fragility. X-irradiation (25-200 rad) did not significantly increase SCE in unilateral retinoblastoma lymphocytes when compared with controls (P greater than 0.50). However, bilaterally affected subjects and three unaffected relatives demonstrated a statistically significant increase in SCE (P less than 0.01). In conclusion, hereditary retinoblastoma lymphocytes appear more radiosensitive than sporadic retinoblastoma, perhaps, reflecting the increased second malignancies in germinal mutation retinoblastoma. In addition, the analysis of radiation-induced SCE in peripheral blood lymphocytes of RB patients and family members may provide a valuable tool increasing the accuracy of genetic counseling for this disorder. Additional studies of RB patients and families are needed to assess the relevance of this approach to genetic counseling

Elevated sister chromatid exchange frequencies in New Zealand Vietnam War veterans.

Science.gov (United States)

Rowland, R E; Edwards, L A; Podd, J V

2007-01-01

From July 1965 until November 1971, New Zealand Defence Force Personnel fought in the Vietnam War. During this time more than 76,500,000 litres of phenoxylic herbicides were sprayed over parts of Southern Vietnam and Laos, the most common being known as 'Agent Orange'. The current study aimed to ascertain whether or not New Zealand Vietnam War veterans show evidence of genetic disturbance arising as a consequence of their now confirmed exposure to these defoliants. A sample group of 24 New Zealand Vietnam War veterans and 23 control volunteers were compared using an SCE (sister chromatid exchange) analysis. The results from the SCE study show a highly significant difference (P Vietnam War veterans studied here were exposed to a clastogenic substance(s) which continues to exert an observable genetic effect today, and suggest that this is attributable to their service in Vietnam. Copyright 2007 S. Karger AG, Basel.

In vitro and occupational induction of sister-chromatid exchanges in human lymphocytes with furfuryl alcohol and furfural

Energy Technology Data Exchange (ETDEWEB)

Gomez-Arroyo, S.; Souza, V.

1985-06-01

Sister-chromatid exchanges (SCEs) in human lymphocytes were studied using the FPG technique in order to determine the cytogenetic effect of furfural and furfuryl alcohol. The induction of SCEs was also investigated in workers occupationally exposed to these solvents that are commonly used in the manufacture of furoic resins. The results obtained from the in vitro treatments show that furfural increased the number of SCEs, while furfuryl alcohol did not. In exposed workers, neither of these solvents increased the spontaneous frequency of SCEs per metaphase.

Use of a ring chromosome and pulsed-field gels to study interhomolog recombination, double-strand DNA breaks and sister-chromatid exchange in yeast

International Nuclear Information System (INIS)

Game, J.C.; Sitney, K.C.; Cook, V.E.; Mortimer, R.K.

1989-01-01

The authors describe a system that uses pulsed-field gels for the physical detection of recombinant DNA molecules, double-strand DNA breaks (DSB) and sister-chromatid exchange in the yeast Saccharomyces cerevisiae. The system makes use of a circular variant of chromosome II (Chr. III). Meiotic recombination between this ring chromosome and a linear homolog produces new molecules of sizes distinguishable on gels from either parental molecule. They demonstrate that these recombinant molecules are not present either in strains with two linear Chr. III molecules or in rad50 mutants, which are defective in meiotic recombination. In conjunction with the molecular endpoints. They present data on the timing of commitment to meiotic recombination scored genetically. They have used x-rays to linearize circular Chr. III, both to develop a sensitive method for measuring frequency of DSB and as a means of detecting double-size circles originating in part from sister-chromatid exchange, which they find to be frequent during meiosis

Evaluation of the persistence in the induction of Sister Chromatid Exchanges (SCE) by alkylating agents

International Nuclear Information System (INIS)

Rodriguez R, R.; Huerta V, C.; MOrales R, P.R.

2006-01-01

The persistence in the induction of sister chromatid exchanges (SCE) by the alkylating agents methyl and ethyl-methanesulfonates (MMS and EMS) was evaluated. For it, to groups of mice its were administered a dose of these agents and later its were analyzed the induced SCE's in two periods: early and late. Both agents caused high increments of SCE in the early period and small in the late one; however, the caused lately by EMS was significantly bigger. This late induction of SCE by EMS possibly is associated with an epigenetic change or with the presence of etiladucts in the phosphodiester bonds of the DNA. (Author)

Sister chromatid exchanges and micronuclei analysis in lymphocytes of men exposed to simazine through drinking water.

Science.gov (United States)

Suárez, Susanna; Rubio, Arantxa; Sueiro, Rosa Ana; Garrido, Joaquín

2003-06-06

In some cities of the autonomous community of Extremadura (south-west of Spain), levels of simazine from 10 to 30 ppm were detected in tap water. To analyse the possible effect of this herbicide, two biomarkers, sister chromatid exchanges (SCE) and micronuclei (MN), were used in peripheral blood lymphocytes from males exposed to simazine through drinking water. SCE and MN analysis failed to detect any statistically significant increase in the people exposed to simazine when compared with the controls. With respect to high frequency cells (HFC), a statistically significant difference was detected between exposed and control groups.

Inhibition of protein synthesis does not antagonize induction of UV-induced sister-chromatid exchange in xeroderma pigmentosum cells

International Nuclear Information System (INIS)

Sono, Akira; Sakaguchi, Kengo.

1988-01-01

Cycloheximide strongly antagonizes the induction of sisterchromatid exchanges by ethyl methanesulfonate or mitomycin C in human skin fibroblast and xeroderma pigmentosum cells (group A). Analogous behavior has been observed in several other species including Chinese hamster and plant cells. This report documents an exception to that pattern: cycloheximide fails to antagonize UV-induced sister chromatid exchange in xeroderma pigmentosum cells, whereas it does in normal human skin fibroblast cells. A genetic defect in these cells is postulated to alter the UV-mediated DNA recombination process. (author)

Sister chromatid exchanges induced in CHO cells by X-rays or 5.5 MeV neutrons

International Nuclear Information System (INIS)

Bocian, E.; Rosiek, O.; Sablinski, J.; Ziemba-Zoltowska, B.

1986-01-01

The induction of sister chromatid exchanges (SCEs) by X-rays (1-9 Gy) and 5.5 MeV neutrons (0.5-4 Gy) was studied in CHO cells. A dose-dependent increase of the frequency of SCE was found for both radiations when cells with BrdUrd substituted DNA were irradiated. The similar doubling dose, approx. 4 Gy, was found for X-rays and neutrons. The increase of the SCE frequency was not clearly dependent on the dose when cells with BrdUrd unsubstituted DNA were irradiated. In this case a dose of 4 Gy enhanced the SCE frequency only by the factor of 1.3. (author)

Sister kinetochores are mechanically fused during meiosis I in yeast.

Science.gov (United States)

Sarangapani, Krishna K; Duro, Eris; Deng, Yi; Alves, Flavia de Lima; Ye, Qiaozhen; Opoku, Kwaku N; Ceto, Steven; Rappsilber, Juri; Corbett, Kevin D; Biggins, Sue; Marston, Adèle L; Asbury, Charles L

2014-10-10

Production of healthy gametes requires a reductional meiosis I division in which replicated sister chromatids comigrate, rather than separate as in mitosis or meiosis II. Fusion of sister kinetochores during meiosis I may underlie sister chromatid comigration in diverse organisms, but direct evidence for such fusion has been lacking. We used laser trapping and quantitative fluorescence microscopy to study native kinetochore particles isolated from yeast. Meiosis I kinetochores formed stronger attachments and carried more microtubule-binding elements than kinetochores isolated from cells in mitosis or meiosis II. The meiosis I-specific monopolin complex was both necessary and sufficient to drive these modifications. Thus, kinetochore fusion directs sister chromatid comigration, a conserved feature of meiosis that is fundamental to Mendelian inheritance. Copyright © 2014, American Association for the Advancement of Science.

Can consumption of raw vegetables decrease the count of sister chromatid exchange? Results from a cross-sectional study in Krakow, Poland

OpenAIRE

Galas, Aleksander; Cebulska-Wasilewska, Antonina

2014-01-01

Background Sister chromatid exchange (SCE) is a widely used sensitive cytogenetic biomarker of exposure to genotoxic and cancerogenic agents. Results of human monitoring studies and cytogenetic damage have revealed that biological effects of genotoxic exposures are influenced by confounding factors related to life-style. Vegetable and fruit consumption may play a role, but available results are not consistent. The purpose of the study was to investigate the effect of consumption of raw and co...

In vivo persistence of sister chromatid exchanges (SCE) induced by gamma rays in mouse bone marrow cells

International Nuclear Information System (INIS)

Morales-Ramirez, P.; Vallarino-Kelly, T.; Rodriguez-Reyes, R.

1984-01-01

The sister chromatid exchange (SCE) frequencies induced in bone marrow cells by in vivo irradiation with gamma rays before or after bromodeoxyuridine (BrdUrd) incorporation were compared. The frequency of SCE at different postirradiation times was also measured in bone marrow cells in vivo, irradiated before BrdUrd incorporation. Increased sensitivity to SCE induction by radiation was found in cells after BrdUrd incorporation for one cycle when compared with cells irradiated before BrdUrd incorporation. The increased SCE frequency persisted for at least 72 hr after the initial irradiation, implying that the gamma ray-induced lesion(s) capable of eliciting an SCE are persistent and cannot be easily repaired

Amount of sister chromatid exchanges and survival of Chinese hamster V79-4 cells after irradiation with 0,7 MeV neutrons

International Nuclear Information System (INIS)

Lapidus, I.L.; Nasonova, E.A.

1987-01-01

The dependence of the survival and induction of sister chromatid exchanges (SCEs) in Chinese hamster V79-4 cells on the dose of γ-rays and neutrons with average energy 0.7 MeV has been analysed. The value of RBE for neutrons was 5.5. It has been shown that the number of SCE increased with the dose of γ-irradiation and no induction could be detected after neutron irradiation

Acute wood or coal exposure with carbon monoxide intoxication induces sister chromatid exchange

Energy Technology Data Exchange (ETDEWEB)

Ozturk, S.; Vatansever, S.; Cefle, K.; Palanduz, S.; Guler, K.; Erten, N.; Erk, O.; Karan, M.A.; Tascioglu, C. [University of Istanbul, Istanbul (Turkey). Istanbul Faculty of Medicine

2002-07-01

The object of this study was to investigate the genotoxic effect of acute overexposure to combustion products originating from coal or wood stoves in patients presenting with acute carbon monoxide intoxication. The authors analyzed the frequency of sister chromatid exchange and the carboxyhemoglobin concentration in 20 consecutive patients without a history of smoking or drug use who had been treated in the Emergency Care Unit of Istanbul Medical Faculty due to acute carbon monoxide intoxication. All of these cases were domestic accidents due to dysfunctioning coal or wood stoves. The results were compared with a control group of 20 nonsmoking, nondrug-using healthy individuals matched for age, sex, and absence of other chemical exposure. It was concluded that acute exposure to combustion products of wood or coal is genotoxic to DNA. Potential causes of genotoxicity include known mutagenic compounds present in coal or wood smoke and ash, oxygen radicals formed during combustion, as well as hypoxic and reperfusion injury mechanisms initiated by carbon monoxide intoxication.

Sister chromatid exchange analysis and chromosoma aberration studies in interventional cardiology laboratory workers. One year follow up study

International Nuclear Information System (INIS)

Erol, M.K.; Oztas, S.; Bozkurt, E.; Karakelleoglu, S.

2002-01-01

Invasive cardiology laboratory workers are occupationally exposed to chronic ionizing radiation. It is known that ionizing radiation has a damaging effect on chromosomes. In present study, we investigated the frequency of sister chromatid exchange (SCE) and chromosomal aberrations in 11 invasive cardiology laboratory workers and 11 healthy controls. After a vacation period, we took blood samples for chromosome analysis in months 0, 4, 8 and 12 (last two month period was the nonradiation time). The SCE frequencies did not change significantly after exposure to ionizing radiation in any worker. Our study has revealed that non-specific structural chromosome aberrations such as gaps, isogaps, acentric chromosomes, chromatids and chromosome breakage could be in the 4th and 8th months after ionizing radiation exposure in the metaphase plaques. All abnormal chromosomal effects had disappeared by the end of the two month non-exposure period in each worker. In conclusion, the results suggest that SCE frequencies are not significantly affected in invasive cardiology laboratory workers who are exposed occupationally to ionizing radiation, although some degree of reversible chromosomal aberrations did appear. (author)

Very low sister-chromatid exchange rate in Seventh-Day Adventists.

Science.gov (United States)

Wulf, H C; Iversen, A S; Husum, B; Niebuhr, E

1986-08-01

42 Seventh-Day Adventists (SDAs) and 42 controls matched for sex, age and occupation had their sister-chromatid exchange (SCE) examined in peripheral blood lymphocytes. This was done to examine if the SCE frequency was lower in this group of people, who are known to have a decreased cancer risk compared to the general population. The average SCE/cell in 30 cells from each person was 5.54 +/- 0.07 (mean +/- standard error of the mean) for the SDAs and 8.00 +/- 0.15 for the controls, the difference being statistically significant (p less than 0.00001). No difference in SCE frequency was found between SDAs eating only an ovo-lacto-vegetarian diet and those eating some fish or meat. The mitotic index (MI) was significantly higher and the replication index (RI) was significantly lower in SDAs than in controls. No correlation was found between gamma (a statistical transformation of SCEs/cell) and MI or RI within the groups of SDAs or controls. In the pooled data there was a negative correlation of gamma and MI and a positive correlation of gamma and RI. Of the interpersonal variation in gamma 8% and 14% could be explained by MI and RI. The finding of a lower SCE frequency in a group of SDAs who have a low risk of cancer might indirectly indicate a relation between SCE and cancer and encourages further studies of SCE and diet.

Role of oxygen free radicals in the induction of sister chromatid exchanges by cigarette smoke

International Nuclear Information System (INIS)

Lee, C.K.; Brown, B.G.; Rice, W.Y. Jr.; Doolittle, D.J.

1989-01-01

Cigarette smoke has been reported to contain free radicals and free radical generators in both the gas and particulate phases. Studies in our laboratory have shown that both cigarette smoke condensate (CSC) and smoke bubbled through phosphate buffered saline solution (smoke-PBS) increased sister chromatid exchanges (SCE) in Chinese hamster ovary cells in a dose-dependent manner. Since oxygen free radicals have been shown to cause SCEs and other chromosomal damage, we investigated the role of these radicals in the induction of SCEs by CSC and smoke-PBS. Addition of the antioxidant enzymes catalase and superoxide dismutase or the oxygen-radical scavenger ascorbic acid failed to reduce the SCE frequency in the presence of either CSC or smoke-PBS. Additional studies indicated that the quantity of hydrogen peroxide produced in CSC or smoke-PBS is too small to account for the observed SCE induction. It appears, therefore, that SCE induction by CSC or smoke-PBS does not involve the participation of oxygen free radicals

Sequential loading of cohesin subunits during the first meiotic prophase of grasshoppers.

Directory of Open Access Journals (Sweden)

Ana M Valdeolmillos

2007-02-01

Full Text Available The cohesin complexes play a key role in chromosome segregation during both mitosis and meiosis. They establish sister chromatid cohesion between duplicating DNA molecules during S-phase, but they also have an important role during postreplicative double-strand break repair in mitosis, as well as during recombination between homologous chromosomes in meiosis. An additional function in meiosis is related to the sister kinetochore cohesion, so they can be pulled by microtubules to the same pole at anaphase I. Data about the dynamics of cohesin subunits during meiosis are scarce; therefore, it is of great interest to characterize how the formation of the cohesin complexes is achieved in order to understand the roles of the different subunits within them. We have investigated the spatio-temporal distribution of three different cohesin subunits in prophase I grasshopper spermatocytes. We found that structural maintenance of chromosome protein 3 (SMC3 appears as early as preleptotene, and its localization resembles the location of the unsynapsed axial elements, whereas radiation-sensitive mutant 21 (RAD21 (sister chromatid cohesion protein 1, SCC1 and stromal antigen protein 1 (SA1 (sister chromatid cohesion protein 3, SCC3 are not visualized until zygotene, since they are located in the synapsed regions of the bivalents. During pachytene, the distribution of the three cohesin subunits is very similar and all appear along the trajectories of the lateral elements of the autosomal synaptonemal complexes. However, whereas SMC3 also appears over the single and unsynapsed X chromosome, RAD21 and SA1 do not. We conclude that the loading of SMC3 and the non-SMC subunits, RAD21 and SA1, occurs in different steps throughout prophase I grasshopper meiosis. These results strongly suggest the participation of SMC3 in the initial cohesin axis formation as early as preleptotene, thus contributing to sister chromatid cohesion, with a later association of both RAD21

Effects of radiation on frequency of chromosomal aberrations and sister chromatid exchange in the benthic worm Neanthes arenaceodentata

International Nuclear Information System (INIS)

Harrison, F.L.; Rice, D.W. Jr.; Moore, D.H.; Varela, M.

1983-04-01

Traditional bioassays are unsuitable for assessing sublethal effects of low levels of radioactivity because mortality and phenotypic responses are not anticipated. We compared the usefulness of chromosomal aberration (CA) and sister chromatid exchange (SCE) induction as measures of low-level radiation effects in a sediment-dwelling marine worm, Neanthes arenaceodentata. Newly hatched larvae were exposed to two radiation exposure regimes. Groups of 100 larvae were exposed to either x rays delivered at high dose rates (0.7 Gy min -1 ) or to 60 Co gamma rays delivered at low dose rates (4.8 X 10 -5 to 1.2 X 10 -1 Gy h -1 ). After irradiation, the larvae were exposed to 3 X 10 -5 M bromodeoxyuridine (BrdUrd) for 28 h (x-ray-irradiated larvae) or for 54 h ( 60 Co-irradiated larvae). Slides of larval cells were prepared for observation of CAs and SCEs. Frequencies of CAs were determined in first division cells; frequencies of SCEs were determined in second division cells. Results from x-ray irradiation indicated that dose-related increases occur in chromosome and chromatid deletions, but an x-ray dose greater than or equal to 2 Gy was required to observe a significant increase. Worm larvae receiving 60 Co irradiation showed elevated SCE frequencies; a significant increase in SCE frequency was observed at 0.6 Gy. 49 references, 2 figures

Phospho-H1 Decorates the Inter-chromatid Axis and Is Evicted along with Shugoshin by SET during Mitosis.

Science.gov (United States)

Krishnan, Swathi; Smits, Arne H; Vermeulen, Michiel; Reinberg, Danny

2017-08-17

Precise control of sister chromatid separation during mitosis is pivotal to maintaining genomic integrity. Yet, the regulatory mechanisms involved are not well understood. Remarkably, we discovered that linker histone H1 phosphorylated at S/T18 decorated the inter-chromatid axial DNA on mitotic chromosomes. Sister chromatid resolution during mitosis required the eviction of such H1S/T18ph by the chaperone SET, with this process being independent of and most likely downstream of arm-cohesin dissociation. SET also directed the disassembly of Shugoshins in a polo-like kinase 1-augmented manner, aiding centromere resolution. SET ablation compromised mitotic fidelity as evidenced by unresolved sister chromatids with marked accumulation of H1S/T18ph and centromeric Shugoshin. Thus, chaperone-assisted eviction of linker histones and Shugoshins is a fundamental step in mammalian mitotic progression. Our findings also elucidate the functional implications of the decades-old observation of mitotic linker histone phosphorylation, serving as a paradigm to explore the role of linker histones in bio-signaling processes. Copyright © 2017 Elsevier Inc. All rights reserved.

Sister chromatid exchanges and structural chromosome aberrations in lymphocytes in operating room personnel

Energy Technology Data Exchange (ETDEWEB)

Husum, B; Niebuhr, E; Wulf, H C; Norgaard, I

1983-06-01

Information on possible chromosomal damage in humans after long-term exposure to trace concentrations of waste anaesthetic gases is scarce. We examined peripheral lymphocytes in operating room personnel for both chromosome aberrations and sister chromatid exchanges (SCE). Following a standardized procedure of cultivation and staining, 30 cells from each person were scored for SCE and 100 cells from each person were examined for chromosome aberrations. A total of 45 persons were examined, representing anaesthetists (n . 15), operating room nurses assisting the surgeon (n . 10), nurses circulating in the operating room (n . 8) and healthy, unexposed controls (n . 12). The median duration of working in the operating room was 102 months, respectively. Time-weighted concentration levels of 2.5-4.3 p.p.m. of halothane and 25-400 p.p.m. of nitrous oxide were measured in the breathing zones of the anaesthetists during mask anaesthesia. Examination of SCE and chromosome aberrations yielded corresponding qualitative results. With both tests, no statistically significant difference was observed between the four groups of persons. It was concluded that by examination of both SCE and chromosome aberrations in peripheral lymphocytes in operating room personnel, no indication was found of a mutagenic effect of long-term exposure to trace concentrations of waste anaesthetic gases.

Alkaline DNA fragmentation, DNA disentanglement evaluated viscosimetrically and sister chromatid exchanges, after treatment in vivo with nitrofurantoin.

Science.gov (United States)

Parodi, S; Pala, M; Russo, P; Balbi, C; Abelmoschi, M L; Taningher, M; Zunino, A; Ottaggio, L; de Ferrari, M; Carbone, A; Santi, L

1983-07-01

Nitrofurantoin was not positive as a carcinogen in long term assays. In vitro it was positive in some short term tests and negative in others. We have examined Nitrofurantoin for its capability of inducing DNA damage in vivo. With the alkaline elution technique, Nitrofurantoin appeared clearly positive in all the tissues examined (liver, kidney, lung, spleen and bone marrow). In the liver we also observed some cross-linking effect. In bone marrow cells Nitrofurantoin was also clearly positive in terms of sister chromatid exchanges (SCEs) induction. DNA damage in vivo was also examined with a viscosimetric method, more sensitive than alkaline elution. With this method the results were essentially negative, suggesting that the two methods detect different types of damage. In view of its positivity in many organs and in two short term tests in vivo, the carcinogenic potential of Nitrofurantoin should be reconsidered.

Merotelic kinetochore attachment in oocyte meiosis II causes sister chromatids segregation errors in aged mice.

Science.gov (United States)

Cheng, Jin-Mei; Li, Jian; Tang, Ji-Xin; Hao, Xiao-Xia; Wang, Zhi-Peng; Sun, Tie-Cheng; Wang, Xiu-Xia; Zhang, Yan; Chen, Su-Ren; Liu, Yi-Xun

2017-08-03

Mammalian oocyte chromosomes undergo 2 meiotic divisions to generate haploid gametes. The frequency of chromosome segregation errors during meiosis I increase with age. However, little attention has been paid to the question of how aging affects sister chromatid segregation during oocyte meiosis II. More importantly, how aneuploid metaphase II (MII) oocytes from aged mice evade the spindle assembly checkpoint (SAC) mechanism to complete later meiosis II to form aneuploid embryos remains unknown. Here, we report that MII oocytes from naturally aged mice exhibited substantial errors in chromosome arrangement and configuration compared with young MII oocytes. Interestingly, these errors in aged oocytes had no impact on anaphase II onset and completion as well as 2-cell formation after parthenogenetic activation. Further study found that merotelic kinetochore attachment occurred more frequently and could stabilize the kinetochore-microtubule interaction to ensure SAC inactivation and anaphase II onset in aged MII oocytes. This orientation could persist largely during anaphase II in aged oocytes, leading to severe chromosome lagging and trailing as well as delay of anaphase II completion. Therefore, merotelic kinetochore attachment in oocyte meiosis II exacerbates age-related genetic instability and is a key source of age-dependent embryo aneuploidy and dysplasia.

Evidence that cyclophosphamide can to induce exchanges in the sister chromatids (ICH) through secondary injuries

International Nuclear Information System (INIS)

Morales R, P.; Rodriguez R, R.

1997-01-01

By means of the use of destination protocol of ICH inductive injuries (DLI-ICH), it was studied if interchanges in the sister chromatids (ICH) induced by cyclophosphamide (CP), in the second post-treatment division (ICH-2) are produced by secondary injuries or by fresh injuries. For discard between these possibilities it was administered CP at different periods before of the first post-treatment division, taking as reference the administered time for high dose of bromodeoxyuridine (BrdU ) which was approximately at the beginning of this division. The ICH frequencies that occur in the first, the second and the third synthesis stages (S) were determined. It was observed that when the administered CP was four hours before BrdU , the ICH frequencies of the second and the third S were reduced. The frequency of the first ICH increased lightly in relation to those of the normal protocol (0.5 h before BrdU ) and that the supplying of CP six hours before caused almost a total reduction of ICH of second and third S and an important increment of ICH of first S.This was interpreted as evidence that the ICH-2 are product of secondary injuries. (Author)

Structure of the Pds5-Scc1 Complex and Implications for Cohesin Function

Directory of Open Access Journals (Sweden)

Kyle W. Muir

2016-03-01

Full Text Available Sister chromatid cohesion is a fundamental prerequisite to faithful genome segregation. Cohesion is precisely regulated by accessory factors that modulate the stability with which the cohesin complex embraces chromosomes. One of these factors, Pds5, engages cohesin through Scc1 and is both a facilitator of cohesion, and, conversely also mediates the release of cohesin from chromatin. We present here the crystal structure of a complex between budding yeast Pds5 and Scc1, thus elucidating the molecular basis of Pds5 function. Pds5 forms an elongated HEAT repeat that binds to Scc1 via a conserved surface patch. We demonstrate that the integrity of the Pds5-Scc1 interface is indispensable for the recruitment of Pds5 to cohesin, and that its abrogation results in loss of sister chromatid cohesion and cell viability.

X-ray sensitization of chromatids with unifilarly and bifilarly substituted DNA

International Nuclear Information System (INIS)

Wolff, S.

1981-01-01

When cells are grown for two rounds of DNA replication in the presence of the thymidine analogue 5-bromodeoxyuridine, chromosomes containing one chromatid with unifilarly substituted DNA and one with bifilarly substituted DNA are found. These can be distinguished by harlequin staining techniques that stain one chromatid dark and one light. When the degree of substitution is 60% or greater, 3 times as many X-ray-induced chromatid breaks are produced as in unsubstituted chromatids. This represents maximal sensitization. The unifilarly substituted (dark) chromatid is as sensitive as its bifilarly substituted (light) sister chromatid. If cells are grown in low concentrations of 5-bromodeoxyuridine (BrdUrd), then the amount of substitution is less and the bifilarly substituted chromatic is more sensitive than the unifilarly substituted one. When large numbers of cells are grown in very low concentrations of BrdUrd, the analogue is almost completely depleted during the first round of replication leading to harlequin chromosomes containing one unsubstituted (dark) and one unifilarly substituted (light) chromatid. Under these conditions a maximal sensitization between light-staining and dark-staining chromatids can occur. This can be confused with the differential sensitivity between unifilarly and bifilarly substituted chromatids. The apparent discrepant results obtained by different investigators are most likely caused by the use of very low levels of BrdUrd in some of the experiments. (orig.)

Enhanced stimulation of chromosomal translocations and sister chromatid exchanges by either HO-induced double-strand breaks or ionizing radiation in Saccharomyces cerevisiae yku70 mutants

International Nuclear Information System (INIS)

Fasullo, Michael; St Amour, Courtney; Zeng Li

2005-01-01

DNA double-strand break (DSB) repair occurs by homologous recombination (HR) or non-homologous endjoining (NHEJ). In Saccharomyces cerevisiae, expression of both MAT a and MATα inhibits NHEJ and facilitates DSB-initiated HR. We previously observed that DSB-initiated recombination between two his3 fragments, his3-Δ5' and his3-Δ3'::HOcs is enhanced in haploids and diploids expressing both MAT a and MATα genes, regardless of the position or orientation of the his3 fragments. Herein, we measured frequencies of DNA damage-associated translocations and sister chromatid exchanges (SCEs) in yku70 haploid mutants, defective in NHEJ. Translocation and SCE frequencies were measured in strains containing the same his3 fragments after DSBs were made directly at trp1::his3-Δ3'::HOcs. Wild type and yku70 cells were also exposed to ionizing radiation and radiomimetic agents methyl methanesulfonate (MMS), phleomycin, and 4-nitroquinolone-1-oxide (4-NQO). Frequencies of X-ray-associated and DSB-initiated translocations were five-fold higher in yku70 mutants compared to wild type; however, frequencies of phleomycin-associated translocations were lower in the yku70 haploid mutant. Frequencies of DSB-initiated SCEs were 1.8-fold higher in the yku70 mutant, compared to wild type. Thus, DSB-initiated HR between repeated sequences on non-homologous chromosomes and sister chromatids occurs at higher frequencies in yku70 haploid mutants; however, higher frequencies of DNA damage-associated HR in yku70 mutants depend on the DNA damaging agent

Sister chromatid exchanges in X-ray irradiated blood lymphocytes from patients with hereditary diseases with radioresistant DNA synthesis

International Nuclear Information System (INIS)

Pleskach, N.M.; Andriadze, M.I.; Mikhel'son, V.M.; Zhestyanikov, V.D.

1988-01-01

X-ray irradiation induced sister chromatid exchanges (SCE) in blood lymphocytes from patient with Down's syndrome and adult progeria (in both the cases radioresistant DNA synthesis takes place). In normal lymphocytes (in which ionizing radiation inhibits the replicative synthesis of DNA) the rate of SCE rises with the rise of radiation dose. Thus, the rate of SCE in X-ray irradiated lymphocytes is in reverse dependence with radioresistance of replicative synthesis of DNA. The data obtained are explained in accordance with the replicative hypothesis of the SCE nature (Painter, 1980a): in cells of patients with Down's syndrome, xeroderma pigmentosum from 2 and progeria of adults the time of existence of partly replicated clusters of replicons is decreased due to radioresistant replicative synthesis of DNA, but the presence of partly replicated clusters of replicons in necessary for SCE formation. Therefore the rate of SCF in X-irradiated cells of these patients decreases

A comparative investigation of DNA strand breaks, sister chromatid exchanges and K-ras gene mutations induced by cadmium salts in cultured human cells

International Nuclear Information System (INIS)

Mouron, Silvana Andrea; Grillo, Claudia Alejandra; Dulout, Fernando Noel; Golijow, Carlos Daniel

2004-01-01

Cadmium (Cd) is a toxic heavy metal of continuing occupational and environmental concern with a wide variety of adverse effects. Several studies have shown that cadmium produces DNA strand breaks, DNA-protein cross-links, oxidative DNA damage, chromosomal aberrations, dysregulation of gene expression resulting in enhanced proliferation, depressed apoptosis and/or altered DNA repair. This study was undertaken to investigate the ability of cadmium chloride (CdCl 2 ) and cadmium sulphate (CdSO 4 ) to induce point mutations in codon 12 of the K-ras protooncogene assessed by polymerase chain reaction-single strand conformation polymorphisms (PCR-SSCP) and RFLP-enriched PCR methods. Also their genotoxic effects were analyzed by the comet assay and sister chromatid exchanges test. The human lung fibroblast cell line MRC-5 was used for the experiments. Sister chromatid exchanges assay (SCEs) frequencies were significantly increased in cells exposed to cadmium salts in relation to controls (p < 0.001). Despite the slow increment observed in the three comet parameters considered when cells were treated with cadmium chloride, significant differences between groups were only found in the variable comet moment (CM) (p < 0.005). On the other hand, when cells were exposed to cadmium sulphate, the Kruskal-Wallis test showed highly significant differences between groups for migration, tail moment and comet moment parameters (p < 0.001). Nevertheless, a null or weak point mutation induction in K-ras protooncogene was detected using polymerase chain reaction-low ionic strength-single strand conformation polymorphisms (PCR-LIS-SSCP) and RFLP-enriched PCR methods when cells were treated with cadmium salts. Thus, inorganic cadmium produces genotoxicity in human lung fibroblast MRC-5 cells, in the absence of significant point mutation of the K-ras gene

Elastatinal and leupeptin: effects on u.v.-induced mutation and sister-chromatid exchanges in Chinese hamster cells

International Nuclear Information System (INIS)

Paul, P.; Fujiwara, Y.

1981-01-01

Microbial protease inhibitors elastatinal and leupeptin were tested for cytotoxicity and for effects on spontaneous and u.v.-induced 6-thioguanine-resistant (6TGsup(r)) mutation and sister-chromatid exchange (SCE) in V79 Chinese hamster cells. Continuous treatment with elastatinal exhibited marked cytotoxicity, while leupeptin was almost non-cytotoxic. Elastatinal rapidly induced cytotoxic effects as a function of its concentration and time of exposure. Near maximum cytotoxicity was reached after exposures of 6-8 h and this was partially abolished by the presence of 2.5 μg cycloheximide per ml. Concentrations of either protease inhibitor which gave 60-80% survival had no appreciable effects on u.v. survival and frequencies of spontaneous and u.v.-induced 6TGsup(r) mutation and SCE. However, reconstruction experiments revealed that pretreatments of 6TGsup(r) and 6TGsup(s) (wild-type) cells with these inhibitors for 6 days tended to block metabolic co-operation in their co-cultures. Thus, elastatinal and leupeptin are neither clastogenic nor mutagenic by themselves, and do not alter mutation fixation and expression. (author)

Elastatinal and leupeptin: effects on u.v.-induced mutation and sister-chromatid exchanges in Chinese hamster cells

International Nuclear Information System (INIS)

Paul, P.; Fujiwara, Y.

1981-01-01

Microbial protease inhibitors elastatinal and leupeptin were tested for cytotoxicity and for effects on spontaneous and u.v.-induced 6-thioguanine-resistant (6TGr) mutation and sister-chromatid exchange (SCE) in V79 Chinese hamster cells. Continuous treatment with elastatinal exhibited marked cytotoxicity, while leupeptin was almost non-cytotoxic. Elastatinal rapidly induced cytotoxic effects as a function of its concentration and time of exposure. Near maximum cytotoxicity was reached after exposure of 6-8 h and this was partially abolished by the presence of 2.5 micrograms cycloheximide per ml. Concentrations of either protease inhibitor which gave 60-80% survival had no appreciable effects on u.v. survival and frequencies of spontaneous and u.v.-induced 6TGr mutation and SCE. However, reconstruction experiments revealed that pretreatments of 6TGr and 6TGs (wild-type) cells with these inhibitors for 6 days tended to block metabolic co-operation in their co-cultures. Thus, elastatinal and leupeptin are neither clastogenic mutagenic by themselves, and do not alter mutation fixation and expression

Cell elongation is an adaptive response for clearing long chromatid arms from the cleavage plane

Science.gov (United States)

Kotadia, Shaila; Montembault, Emilie; Sullivan, William

2012-01-01

Chromosome segregation must be coordinated with cell cleavage to ensure correct transmission of the genome to daughter cells. Here we identify a novel mechanism by which Drosophila melanogaster neuronal stem cells coordinate sister chromatid segregation with cleavage furrow ingression. Cells adapted to a dramatic increase in chromatid arm length by transiently elongating during anaphase/telophase. The degree of cell elongation correlated with the length of the trailing chromatid arms and was concomitant with a slight increase in spindle length and an enlargement of the zone of cortical myosin distribution. Rho guanine-nucleotide exchange factor (Pebble)–depleted cells failed to elongate during segregation of long chromatids. As a result, Pebble-depleted adult flies exhibited morphological defects likely caused by cell death during development. These studies reveal a novel pathway linking trailing chromatid arms and cortical myosin that ensures the clearance of chromatids from the cleavage plane at the appropriate time during cytokinesis, thus preserving genome integrity. PMID:23185030

Unique geometry of sister kinetochores in human oocytes during meiosis I may explain maternal age-associated increases in chromosomal abnormalities

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Jessica Patel

2016-02-01

Full Text Available The first meiotic division in human oocytes is highly error-prone and contributes to the uniquely high incidence of aneuploidy observed in human pregnancies. A successful meiosis I (MI division entails separation of homologous chromosome pairs and co-segregation of sister chromatids. For this to happen, sister kinetochores must form attachments to spindle kinetochore-fibres emanating from the same pole. In mouse and budding yeast, sister kinetochores remain closely associated with each other during MI, enabling them to act as a single unified structure. However, whether this arrangement also applies in human meiosis I oocytes was unclear. In this study, we perform high-resolution imaging of over 1900 kinetochores in human oocytes, to examine the geometry and architecture of the human meiotic kinetochore. We reveal that sister kinetochores in MI are not physically fused, and instead individual kinetochores within a pair are capable of forming independent attachments to spindle k-fibres. Notably, with increasing female age, the separation between kinetochores increases, suggesting a degradation of centromeric cohesion and/or changes in kinetochore architecture. Our data suggest that the differential arrangement of sister kinetochores and dual k-fibre attachments may explain the high proportion of unstable attachments that form in MI and thus indicate why human oocytes are prone to aneuploidy, particularly with increasing maternal age.

Effect of chlorophyllin on frequency radiation-induced of sister chromatid exchanges (SCE) and other cytogenetic events in mice bone marrow cells In Vivo

International Nuclear Information System (INIS)

Garcia Rodriguez, M.C.

1992-01-01

The effect of chlorophyllin on gamma radiation induced Sister chromatid exchanges (SCE) and on the mitotic index (IM) and average generation time was determined. Groups of mice were treated in one of the following regimens: (1) untreated, (2) treated with chlorophyllin only, (3) irradiated and (4) treated with chlorophyllin and irradiated intraperitoneal administration of chlorophyllin preceding gamma radiation exposure protected again SCE induction and diminution of IM. However, radioprotection was not reflected in the average generation time for the chlorophyllin per se acceleration the average generation time. The results suggest that, under the experimental conditions of the study the SCE and IM are caused by free radicals produced by radiation and wat the action mechanics of chlorophyllin is scavenger free radicals. (Author)

Health assessment of gasoline and fuel oxygenate vapors: micronucleus and sister chromatid exchange evaluations.

Science.gov (United States)

Schreiner, Ceinwen A; Hoffman, Gary M; Gudi, Ramadevi; Clark, Charles R

2014-11-01

Micronucleus and sister chromatid exchange (SCE) tests were performed for vapor condensate of baseline gasoline (BGVC), or gasoline with oxygenates, methyl tert-butyl ether (G/MTBE), ethyl tert butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), t-butyl alcohol (TBA), or ethanol (G/EtOH). Sprague Dawley rats (the same 5/sex/group for both endpoints) were exposed to 0, 2000, 10,000, or 20,000mg/m(3) of each condensate, 6h/day, 5days/week over 4weeks. Positive controls (5/sex/test) were given cyclophosphamide IP, 24h prior to sacrifice at 5mg/kg (SCE test) and 40mg/kg (micronucleus test). Blood was collected from the abdominal aorta for the SCE test and femurs removed for the micronucleus test. Blood cell cultures were treated with 5μg/ml bromodeoxyuridine (BrdU) for SCE evaluation. No significant increases in micronucleated immature erythrocytes were observed for any test material. Statistically significant increases in SCE were observed in rats given BGVC alone or in female rats given G/MTBE. G/TAME induced increased SCE in both sexes at the highest dose only. Although DNA perturbation was observed for several samples, DNA damage was not expressed as increased micronuclei in bone marrow cells. Inclusion of oxygenates in gasoline did not increase the effects of gasoline alone or produce a cytogenetic hazard. Copyright © 2014 Elsevier Inc. All rights reserved.

Frequencies of chromosomal aberrations and sister chromatid exchanges in the benthic worm Neanthes arenaceodentata exposed to ionizing radiation

International Nuclear Information System (INIS)

Harrison, F.L.; Rice, D.W. Jr.; Moore, D.H.

1984-07-01

Traditional bioassays are unsuitable for assessing sublethal effects from ocean disposal of low-level radioactive waste because mortality and phenotypic responses are not anticipated. We compared the usefulness of chromosomal aberration and sister chromatid exchange (SCE) induction as measures of low-level radiation effects in a sediment-dwelling marine worm, Neanthes arenaceodentata. The SCEs, in contrast to chromosomal aberrations, do not alter the overall chromosome morphology and in mammalian cells appear to be a more sensitive indicator of DNA alterations caused by environmental mutagens. Newly hatched larvae were exposed to two radiation-exposure regimes of either x rays at a high dose rate of 0.7 Gy (70 rad)/min for as long as 5.5 min or to 60 Co gamma rays at a low dose rate of from 4.8 x 10 -5 to 1.2 x 10 -1 Gy (0.0048 to 12 rad)/h for 24 h. After irradiation, the larvae were exposed to 3 x 10 -5 M bromodeoxyuridine (BrdUrd) for 28 h (x-ray-irradiated larvae) or for 54 h ( 60 Co-irradiated larvae). Larval cells were examined for the proportion of cells in first, second, and third or greater division. Frequencies of chromosomal aberrations and SCEs were determined in first and second division cells, respectively. Results from x-ray irradiation indicated that dose-related increases occur in chromosome and chromatid deletions, but a dose of equal or greater 2 Gy (equal to or greater than 200 rad) was required to observe a significant increase. Worm larvae receiving 60 Co irradiation showed elevated SCE frequencies with a significant increase of 0.6 Gy (60 rad). We suggest that both SCEs and chromosomal aberrations may be useful for measuring effects on genetic material induced by radiation. 56 references, 7 figures, 9 tables

Increased UV-induced sister-chromatid exchange in cultured fibroblasts of first-degree relatives of melanoma patients

International Nuclear Information System (INIS)

Knees-Matzen, S.; Roser, M.; Reimers, U.; Ehlert, U.; Weichenthal, M.; Breitbart, E.W.; Ruediger, H.W.

1991-01-01

Cultured fibroblasts of 17 first-degree relatives of familial melanoma patients and six first-degree relatives of cutaneous melanoma (CMM) patients with multiple CMM primaries were tested for in vitro sensitivity to UV light. Fibroblasts of nine familial CMM patients with a known UV-sensitivity and 19 healthy probands served as a control. Sister chromatid exchange (SCE) was used as a parameter to detect UV-induced genotoxic damage. The authors found significantly (p less than 0.001) increased UV-induced SCE levels in familial melanoma patients, as well as in first-degree relatives of familial melanoma patients (p less than 0.001) after UV-A,B irradiation (375 J/m2), compared to the healthy probands without a family history of CMM. A significant (p less than 0.001) increase of UV-induced SCE was also observed in the relatives of CMM patients with multiple CMM primaries. In addition, the spontaneous SCE were significantly increased (p less than 0.05) in familial CMM patients. This study shows that increased UV sensitivity is a familial phenomenon. It is consistent with the concept of a genetic predisposition to CMM, which is based on increased UV sensitivity and may help to define groups with an elevated risk of developing cutaneous malignant melanoma

Chl1 DNA helicase regulates Scc2 deposition specifically during DNA-replication in Saccharomyces cerevisiae.

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Soumya Rudra

Full Text Available The conserved family of cohesin proteins that mediate sister chromatid cohesion requires Scc2, Scc4 for chromatin-association and Eco1/Ctf7 for conversion to a tethering competent state. A popular model, based on the notion that cohesins form huge ring-like structures, is that Scc2, Scc4 function is essential only during G1 such that sister chromatid cohesion results simply from DNA replisome passage through pre-loaded cohesin rings. In such a scenario, cohesin deposition during G1 is temporally uncoupled from Eco1-dependent establishment reactions that occur during S-phase. Chl1 DNA helicase (homolog of human ChlR1/DDX11 and BACH1/BRIP1/FANCJ helicases implicated in Fanconi anemia, breast and ovarian cancer and Warsaw Breakage Syndrome plays a critical role in sister chromatid cohesion, however, the mechanism through which Chl1 promotes cohesion remains poorly understood. Here, we report that Chl1 promotes Scc2 loading unto DNA such that both Scc2 and cohesin enrichment to chromatin are defective in chl1 mutant cells. The results further show that both Chl1 expression and chromatin-recruitment are tightly regulated through the cell cycle, peaking during S-phase. Importantly, kinetic ChIP studies reveals that Chl1 is required for Scc2 chromatin-association specifically during S-phase, but not during G1. Despite normal chromatin enrichment of both Scc2 and cohesin during G1, chl1 mutant cells exhibit severe chromosome segregation and cohesion defects--revealing that G1-loaded cohesins is insufficient to promote cohesion. Based on these findings, we propose a new model wherein S-phase cohesin loading occurs during DNA replication and in concert with both cohesion establishment and chromatin assembly reactions--challenging the notion that DNA replication fork navigates through or around pre-loaded cohesin rings.

Assessment of DNA Damage in Peripheral Blood Lymphocytes of Radiation Workers at Al-Tuwaitha Site by Using the Sister Chromatid Exchange and the Comet Assay

International Nuclear Information System (INIS)

Ali, A.K.; Muttar, A.J.; Khayon, S.K.; Haider, Y.L.; Ali, H.F.; Abdullah, A.K.

2015-01-01

The sister chromatid exchange was performed on peripheral blood lymphocytes obtained from 40 individuals of workers occupationally exposed to low ionizing radiation doses in Al-Tuwaitha site due to decommissioning to radioactive contamination then compared with 40 control individuals living in Baghdad. SCEs were scored in metaphase chromosomes were identified by fluorescent plus Giemsa staining (Figure 2).The mean frequencies of SCEs per cell differed significantly (p≺0 0.05) between individuals of radiation workers and control, being 7.78 0.45 SCE/cells and 6.28 0.22 SCE/cells , respectively. However SCE frequency was statistically significant (P≺0 0.05) among radiation workers as compared to control individuals.

Effect of chlorophyllin on induction of exchanges in sister chromatids by gamma irradiation in mice spermatogonia in vivo

International Nuclear Information System (INIS)

Mendiola C, M.T.

1994-01-01

Mouse were exposed to different doses of gamma radiation and the effect on Sister Chromatid Exchange (SCE) frequency in spermatogonias was evaluated. The effect was analyzed before and after Bromodeoxyuridine (BrdU) incorporation to determine the interference of such agent with the cellular response induced by radiation. The capacity of chlorophyllin (sodium and Copper salt derivative from chlorophyll) to reduce SCE induction by radiation in normal and BrdU radio sensitized spermatogonia was also determined. The results indicate that there was a significant increase in SCE frequency by gamma radiation exposure in these cells, such effect was higher irradiating after BrdU incorporation than before. This fact confirms previous observations that BrdU sensitizes some cells to SCE induction. With regard to the chlorophyllin effect, it was determined that this salt acts as a radioprotector reducing gamma-rays induced SCE before or after BrdU incorporation Total protection was obtained with 200 μg of chlorophyllin per g of body weight in both protocols. Under the experimental conditions this study there was no evidence of genotoxicity induced by chlorophyllin itself. The results suggest that this agent may act as a radioprotector by scavenging free radicals produced by gamma-radiation which cause DNA lesions that are involved in SCE formation. (Author)

Effects of hyperthermia and x irradiation on sister chromatid exchange (SCE) frequency in Chinese hamster ovary (CHO) cells

International Nuclear Information System (INIS)

Livingston, G.K.; Dethlefsen, L.A.

1979-01-01

The BrdUrd labeling method was used to evaluate the effects of hyperthermia, x irradiation, and the combined treatment on the incidence of sister chromatid exchange (SCE) in Chinese hamster ovary (CHO) cells. Cells cultured in McCoy's 5A media containing 10 μM 5-bromodeoxyuridine were synchronized after one cell cycle by mitotic shake-off. Early-G 1 cells were heated by submerging culture flasks in a 44 +- 0.05 0 C water bath for periods of 20, 40, and 60 min. By the same method, other cultures were x irradiated at doses of 100, 200, 400, and 600 rad. A third protocol involved combined treatment of 20 min at 44 0 C followed immediately by one of the above radiation doses. A fourth protocol reversed the sequence of the combined treatment applying x irradiation (200 or 400 rad) followed immediately by hyperthermia. The data showed that hyperthermia and x irradiation both elevated the frequency of SCEs significantly whether applied separately or together. The combined treatment (heat: 20 min at 44 0 C plus varying x-radiation doses) produced results suggestive of a synergistic interaction. The sequence of the heat and x irradiation did not appear to have a significant effect on the production of SCE

Protection of halogenated DNA from strand breakage and sister-chromatid exchange induced by the topoisomerase I inhibitor camptothecin

International Nuclear Information System (INIS)

Orta, Manuel Luis; Mateos, Santiago; Cantero, Gloria; Wolff, Lisa J.; Cortes, Felipe

2008-01-01

The fundamental nuclear enzyme DNA topoisomerase I (topo I), cleaves the double-stranded DNA molecule at preferred sequences within its recognition/binding sites. We have recently reported that when cells incorporate halogenated nucleosides analogues of thymidine into DNA, it interferes with normal chromosome segregation, as shown by an extraordinarily high yield of endoreduplication, and results in a protection against DNA breakage induced by the topo II poison m-AMSA [F. Cortes, N. Pastor, S. Mateos, I. Dominguez, The nature of DNA plays a role in chromosome segregation: endoreduplication in halogen-substituted chromosomes, DNA Repair 2 (2003) 719-726; G. Cantero, S. Mateos, N. Pastor; F. Cortes, Halogen substitution of DNA protects from poisoning of topoisomerase II that results in DNA double-strand breaks (DSBs), DNA Repair 5 (2006) 667-674]. In the present investigation, we have assessed whether the presence of halogenated nucleosides in DNA diminishes the frequency of interaction of topo I with DNA and thus the frequency with which the stabilisation of cleavage complexes by the topo I poison camptothecin (CPT) takes place, in such a way that it protects from chromosome breakage and sister-chromatid exchange. This protective effect is shown to parallel a loss in halogen-substituted cells of the otherwise CPT-increased catalytic activity bound to DNA

The Relationship between Dioxin Congeners in the Breast Milk of Vietnamese Women and Sister Chromatid Exchange

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Hiroyuki Suzuki

2014-04-01

Full Text Available The aim of this study was to clarify the relationship between dioxin concentrations in breast milk and the sister chromatid exchange (SCE frequency in women from herbicide-sprayed and non sprayed areas. Blood samples were taken from 21 women with high TCDD (tetrachlorodibenzo-p-dioxin levels from sprayed areas, 23 women with moderate TCDD levels from sprayed areas, and 19 women from non sprayed areas to determine their SCE frequency. The SCE frequencies for the high and moderate TCDD groups from the sprayed area and for the non sprayed area group were 2.40, 2.19, and 1.48 per cell, respectively. Multiple regression analysis showed that the standardized β values for 1,2,3,6,7,8-hexaCDD (β = 0.60, 1,2,3,4,6,7,8-heptaCDD (β = 0.64, and octaCDD (β = 0.65 were higher than those for TCDD (β = 0.34 and 1,2,3,7,8-pentaCDD (β = 0.42. The adjusted R2 value for polyCDDs (R2 = 0.38 was higher than that for polyCDD toxic equivalents (TEQ (toxic equivalents; R2 = 0.23. This study therefore shows that levels of hexa-, hepta-, and octaCDD, which were previously regarded as being less toxic than TCDD, are closely related to SCE frequency and that the level of dioxin (pg/g lipid is potentially more useful as an indicator than TEQ value for explaining SCE frequency.

Cleavage of cohesin rings coordinates the separation of centrioles and chromatids.

Science.gov (United States)

Schöckel, Laura; Möckel, Martin; Mayer, Bernd; Boos, Dominik; Stemmann, Olaf

2011-07-10

Cohesin pairs sister chromatids by forming a tripartite Scc1-Smc1-Smc3 ring around them. In mitosis, cohesin is removed from chromosome arms by the phosphorylation-dependent prophase pathway. Centromeric cohesin is protected by shugoshin 1 and protein phosphatase 2A (Sgo1-PP2A) and opened only in anaphase by separase-dependent cleavage of Scc1 (refs 4-6). Following chromosome segregation, centrioles loosen their tight orthogonal arrangement, which licenses later centrosome duplication in S phase. Although a role of separase in centriole disengagement has been reported, the molecular details of this process remain enigmatic. Here, we identify cohesin as a centriole-engagement factor. Both premature sister-chromatid separation and centriole disengagement are induced by ectopic activation of separase or depletion of Sgo1. These unscheduled events are suppressed by expression of non-cleavable Scc1 or inhibition of the prophase pathway. When endogenous Scc1 is replaced by artificially cleavable Scc1, the corresponding site-specific protease triggers centriole disengagement. Separation of centrioles can alternatively be induced by ectopic cleavage of an engineered Smc3. Thus, the chromosome and centrosome cycles exhibit extensive parallels and are coordinated with each other by dual use of the cohesin ring complex.

Sequence Classification: 890748 [

Lifescience Database Archive (English)

Full Text Available in, involved in maintaining sister chromatid cohesion during meiosis I as well as promoting proper attachmen...t of kinetochores to the spindle during meiosis I and meiosis II; Spo13p || http://www.ncbi.nlm.nih.gov/protein/6321802 ...

Phenotypic variability in 49 cases of ESCO2 mutations, including novel missense and codon deletion in the acetyltransferase domain, correlates with ESCO2 expression and establishes the clinical criteria for Roberts syndrome

DEFF Research Database (Denmark)

Vega, H; Trainer, A H; Gordillo, M

2010-01-01

Roberts syndrome (RBS) and SC phocomelia are caused by mutations in ESCO2, which codes for an acetyltransferase involved in the regulation of sister chromatid cohesion. Of 26 mutations described to date, only one missense mutation has been reported and all others are predicted to be truncating...

Phenotypic variability in 49 cases of ESCO2 mutations, including novel missense and codon deletion in the acetyltransferase domain, correlates with ESCO2 expression and establishes the clinical criteria for Roberts syndrome

NARCIS (Netherlands)

Vega, H.; Trainer, A.H.; Gordillo, M.; Crosier, M.; Kayserili, H.; Skovby, F.; Uzielli, M.L.G.; Schnur, R.E.; Manouvrier, S.; Blair, E.; Hurst, J.A.; Forzano, F.; Meins, M.; Simola, K.O.J.; Raas-Rothschild, A; Hennekam, R.C.M.; Jabs, E.W.

2010-01-01

Background Roberts syndrome (RBS) and SC phocomelia are caused by mutations in ESCO2, which codes for an acetyltransferase involved in the regulation of sister chromatid cohesion. Of 26 mutations described to date, only one missense mutation has been reported and all others are predicted to be

DNA Catenation Maintains Structure of Human Metaphase Chromosomes

DEFF Research Database (Denmark)

L. V. Bauer, David; Marie, Rodolphe; Rasmussen, Kristian Hagsted

2012-01-01

Mitotic chromosome structure is pivotal to cell division but difficult to observe in fine detail using conventional methods. DNA catenation has been implicated in both sister chromatid cohesion and chromosome condensation, but has never been observed directly. We have used a lab-on-a-chip microfl...

Evaluation of the persistence in the induction of Sister Chromatid Exchanges (SCE) by alkylating agents; Evaluacion de la persistencia en la induccion de Intercambio en las Cromatidas Hermanas (ICH) por agentes alquilantes

Energy Technology Data Exchange (ETDEWEB)

Rodriguez R, R.; Huerta V, C.; MOrales R, P.R. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

2006-07-01

The persistence in the induction of sister chromatid exchanges (SCE) by the alkylating agents methyl and ethyl-methanesulfonates (MMS and EMS) was evaluated. For it, to groups of mice its were administered a dose of these agents and later its were analyzed the induced SCE's in two periods: early and late. Both agents caused high increments of SCE in the early period and small in the late one; however, the caused lately by EMS was significantly bigger. This late induction of SCE by EMS possibly is associated with an epigenetic change or with the presence of etiladucts in the phosphodiester bonds of the DNA. (Author)

Evaluation of the persistence in the induction of Sister Chromatid Exchanges (SCE) by alkylating agents; Evaluacion de la persistencia en la induccion de Intercambio en las Cromatidas Hermanas (ICH) por agentes alquilantes

Energy Technology Data Exchange (ETDEWEB)

Rodriguez R, R; Huerta V, C; MOrales R, P R [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

2006-07-01

The persistence in the induction of sister chromatid exchanges (SCE) by the alkylating agents methyl and ethyl-methanesulfonates (MMS and EMS) was evaluated. For it, to groups of mice its were administered a dose of these agents and later its were analyzed the induced SCE's in two periods: early and late. Both agents caused high increments of SCE in the early period and small in the late one; however, the caused lately by EMS was significantly bigger. This late induction of SCE by EMS possibly is associated with an epigenetic change or with the presence of etiladucts in the phosphodiester bonds of the DNA. (Author)

Persistence of sister chromatid exchanges and in vitro morphological transformation of Syrian hamster fetal cells by chemical and physical carcinogens

International Nuclear Information System (INIS)

Popescu, N.C.; Amsbaugh, S.C.; DiPaolo, J.A.

1985-01-01

The induction of neoplastic cell transformation is closely associated with DNA alterations which occur shortly after carcinogen exposure. Sister chromatid exchange (SCE) formation is a sensitive indicator of carcinogen-DNA interaction and correlates with the induction of morphological cell transformation. The persistence of lesions generating SCE produced by chemical and physical carcinogens and its relevance to the induction of morphologic transformation was evaluated in coordinated experiments with cultured Syrian hamster fetal cells (HFC). Exponentially growing HFC were exposed for 1 h to benzo[a]pyrene (BP), methyl-methanesulfonate (MMS), cis-platinum (II) diaminedichloride (cis Pt II), N-methyl-N'-nitrosourea (MNU), mitomycin C (MMC), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), N-acetoxy-2-fluorenyl-acetamide (AcAAF) or u.v. light irradiated. SCE analysis demonstrates that for a period of 48 h after carcinogen exposure, during which time the cells undergo at least four replicative cycles, DNA damage generating SCE induced by all chemical carcinogens either persisted or was partially removed, whereas u.v.-induced lesions were completely removed. An elevated SCE frequency persisted after two additional cell cycles after treatment with BP, AcAAF or MMC without increased cell lethality as compared to other carcinogens whose lesions were completely eliminated during the same period

Trex2 enables spontaneous sister chromatid exchanges without facilitating DNA double-strand break repair.

Science.gov (United States)

Dumitrache, Lavinia C; Hu, Lingchuan; Son, Mi Young; Li, Han; Wesevich, Austin; Scully, Ralph; Stark, Jeremy; Hasty, Paul

2011-08-01

Trex2 is a 3' → 5' exonuclease that removes 3'-mismatched sequences in a biochemical assay; however, its biological function remains unclear. To address biology we previously generated trex2(null) mouse embryonic stem (ES) cells and expressed in these cells wild-type human TREX2 cDNA (Trex2(hTX2)) or cDNA with a single-amino-acid change in the catalytic domain (Trex2(H188A)) or in the DNA-binding domain (Trex2(R167A)). We found the trex2(null) and Trex2(H188A) cells exhibited spontaneous broken chromosomes and trex2(null) cells exhibited spontaneous chromosomal rearrangements. We also found ectopically expressed human TREX2 was active at the 3' ends of I-SceI-induced chromosomal double-strand breaks (DSBs). Therefore, we hypothesized Trex2 participates in DNA DSB repair by modifying 3' ends. This may be especially important for ends with damaged nucleotides. Here we present data that are unexpected and prompt a new model. We found Trex2-altered cells (null, H188A, and R167A) were not hypersensitive to camptothecin, a type-1 topoisomerase inhibitor that induces DSBs at replication forks. In addition, Trex2-altered cells were not hypersensitive to γ-radiation, an agent that causes DSBs throughout the cell cycle. This observation held true even in cells compromised for one of the two major DSB repair pathways: homology-directed repair (HDR) or nonhomologous end joining (NHEJ). Trex2 deletion also enhanced repair of an I-SceI-induced DSB by both HDR and NHEJ without affecting pathway choice. Interestingly, however, trex2(null) cells exhibited reduced spontaneous sister chromatid exchanges (SCEs) but this was not due to a defect in HDR-mediated crossing over. Therefore, reduced spontaneous SCE could be a manifestation of the same defect that caused spontaneous broken chromosomes and spontaneous chromosomal rearrangements. These unexpected data suggest Trex2 does not enable DSB repair and prompt a new model that posits Trex2 suppresses the formation of broken

In vivo study on the replicative model validity of sister chromatid exchanges production

International Nuclear Information System (INIS)

Cruz V, V.L.

1996-01-01

The sister chromatid exchanges (SCE) frequency determination has been used as index of damage to DNA, however the biological meaning of this event is still ignored. Different models in order to explain the mechanism of their formation have been proposed and they could be contained in two categories: a) those that consider that the SCE is produced by means of discreet lesions to the DNA and that they occur in the place of the lesion, and b) those that propose that the SCE is caused by a group of lesions and that therefore the place in which they occur could not be associated with a lesion in particular. The model of Painter (1980) belongs to this last group. It suggests that the region of the DNA where the clusters are united, is the only place in which the exchange of double chain could happen during the synthesis of the DNA and makes the prediction that since the x rays retard the beginning of the duplication, the pretreatment with ionizing radiation would reduce the frequency of SCE induced by agents capable to block the lengthening of the chain of DNA, that are the most efficient SCE inducers. The objective of the present work was to establish the validity of this replicative model for the SCE formation, based in its prediction. The effect of the unilateral preexposition of mouse to gamma radiation was determined on the SCE induction by Mitomycin C (MMC), in cells of the femoral bone marrow In vivo. This strategy allows to determine the effect of the pretreatment in the same organism, minimizing the variability of the response between individuals. There was not a significant variability between the frequencies of SCE, basal and induced by gamma radiation or MMC in the same organism. The animals that received the gamma radiation pretreatment, showed a reduction of approximately the 30 % in the frequency of SCE, assuming an additive effect of the radiation with the MMC. These results coincide with the prediction of the model of Painter, however it is not

Micronuclear and sister chromatid exchange analyses in peripheral lymphocytes of patients with oral lichen planus--a pilot study.

Science.gov (United States)

Ergun, S; Warnakulasuriya, S; Duman, N; Saruhanoğlu, A; Sevinç, B; Oztürk, S; Ozel, S; Cefle, K; Palanduz, S; Tanyeri, H

2009-10-01

The purpose of this study was to determine the genetic instability of peripheral blood lymphocytes from patients diagnosed with oral lichen planus (OLP) by investigation of frequencies of micronuclei (MN) and sister chromatid exchange (SCE). A total of 22 newly diagnosed and untreated patients with OLP of same severity scores and twenty healthy controls participated in this study. They were all non-smokers with no previous history or family history of cancer. The periodontal status, flow rate and buffering capacity of whole mouth saliva were recorded. SCE and MN analyses were performed on peripheral blood lymphocytes of OLP patients and healthy controls. The frequencies of MN (50.00 +/- 22.36) and SCE (6.89 +/- 1.48) in OLP patients were found to be significantly elevated compared with that in normal individuals (25.20 +/- 9.52 and 5.93 +/- 1.31; z = 3.946, P = 0.0001; z = 2.346, P = 0.019). There were no significant differences in the MN frequency and SCE between the two subgroups with reticular or erosive types of OLP. These pilot data indicate an increased genomic instability in peripheral blood lymphocytes of a cohort of Turkish patients diagnosed with oral lichen planus as compared with that of healthy individuals. As patients with OLP may have an increased or potential risk for oral malignancy, these assays could be used in translational research to monitor beneficial effects of interventions and long-term prognosis.

Effect of low 60Co dose rates on sister chromatid exchange incidence in the benthic worm. Neanthes arenaceodentata

International Nuclear Information System (INIS)

Harrison, F.L.; Rice, D.W. Jr.

1981-01-01

The usefulness of sister chromatid exchange (SCE) induction as a measure of low-level radiation effect was examined in a benthic marine worm, Neanthes arenaceodentata. Larvae were exposed to 60 Co radiation for 12 to 24 h at total doses ranging from 0.5 to 309 R and at dose rates from 0.04 to 13 R/h. Animals exposed at intermediate dose rates (0.5, 0.6, 1.25, 2.0, and 2.5 R/h) had SCE frequencies per chromosome about twice that of those receiving no radiation (controls), whereas those exposed at the higher dose rates (7.0 and 13 R/h) had SCE frequencies lower than the controls. Animals exposed at the lower dose rates (0.04 and 0.1 R/h) had lower SCE frequencies than those exposed at intermediate dose rates (and higher SCE frequencies than controls). The length of chromosome pair number one differed among metaphase spreads and was used as an index of chromosome condensation in a given metaphase. Because there is a possibility that chromosome morphology may affect the ability to resolve SCEs, morphology will be monitored in future studies. A preliminary experiment was performed to assess the effects of 2.2 and 11.5 R/h for 24 h on growth and development. Larvae observed at 6 and 17 d after irradiation did not have significantly different numbers of abnormal larvae or survival rates

Differences in sensitivity of murine spermatogonia and somatic cells in vivo to sister-chromatid exchange induction by nitrosoureas.

Science.gov (United States)

Morales-Ramírez, P; Cruz-Vallejo, V; Rodríguez-Reyes, R

2001-07-01

Previously published data indicate that spermatogonia (SPG) are less sensitive to a sister-chromatid exchange (SCE) induction for different mutagens. In an earlier study, we have observed that bromodeoxyuridine (BrdU) substituted murine SPG are less sensitive to SCE induction by gamma ray in cells, than bone marrow (BM) and salivary gland (SG) cells in vivo. This was interpreted to mean that SPG are more efficient in DNA repair or are less prone to SCE induction. That the lower induction of SCE could be due to a reduced accessibility of mutagens to the SPG by virtue of a physiological barrier, was discarded by using gamma radiation. The aim of the present study was to establish whether or not there are differences in SCE induction by nitrosoureas among SPG, SG and BM cells with BrdU substituted or unsubstituted DNA. It was observed that SCE induction by methylnitrosourea (MNU) or by ethylnitrosourea (ENU) in SPG was, respectively, five and two times lower than in SG, and ten and three times lower than in BM. In SPG after BrdU incorporation, there was no increase in efficiency of SCE induction; in fact, there was even a slight decrease by exposure to MNU or ENU. BM and SG cells showed an increased efficiency in SCE induction after BrdU incorporation. This implies that SPG are also less sensitive to SCE induction by nitrosoureas, which cause a different kind of damage from previously assayed mutagens.

Chromosome variant 1qh− and its influence on the 3D organization ...

Indian Academy of Sciences (India)

2014-04-21

Apr 21, 2014 ... protein for sister chromatid cohesion during S phase, is char- ... tansky in 1860, the mechanisms responsible for the disease ... the Ethics Review Committee on Human Research of the ... somes 1 with equal size of heterochromatic segments in a healthy control subject (A1) .... But, literature reports about the.

Can consumption of raw vegetables decrease the count of sister chromatid exchange? Results from a cross-sectional study in Krakow, Poland.

Science.gov (United States)

Galas, Aleksander; Cebulska-Wasilewska, Antonina

2015-03-01

Sister chromatid exchange (SCE) is a widely used sensitive cytogenetic biomarker of exposure to genotoxic and cancerogenic agents. Results of human monitoring studies and cytogenetic damage have revealed that biological effects of genotoxic exposures are influenced by confounding factors related to life-style. Vegetable and fruit consumption may play a role, but available results are not consistent. The purpose of the study was to investigate the effect of consumption of raw and cooked vegetables and fruits on SCE frequency. A total of 62 participants included colorectal cancer (CRC) patients, hospital-based controls and healthy laboratory workers. SCE frequency was assessed in blood lymphocytes. Frequency of vegetable and fruit consumption was gathered by structured semi-quantitative food frequency questionnaire. SCE frequency was lowest among hospital-based controls (4.4 ± 1.1), a bit higher in CRC patients (4.5 ± 1.0) and highest among laboratory workers (7.4 ± 1.2) (p consumption, but not so for intake of cooked vegetables and fruits. The results of the study have shown the beneficial effect of consumption of raw vegetables on disrupted replication of DNA measured by SCE frequency, implying protection against genotoxic agents. Further effort is required to verify the role of cooked vegetables and fruits.

Variation in sister chromatid exchange frequencies between human and pig whole blood, plasma leukocyte, and mononuclear leukocyte cultures

International Nuclear Information System (INIS)

Larramendy, M.L.; Reigosa, M.A.

1986-01-01

Sister chromatid exchange (SCE) induction by ultraviolet (UV) light was studied in both human and pig whole blood cultures (WBC) and plasma leukocyte cultures (PLC). No variation in SCE frequency was observed between pig WBC and PLC in control as well as in treated cells. Conversely, SCE frequencies of human PLC were consistently higher than those of WBC in control and UV-exposed cells. Thus, red blood cells (RBCs) do not influence the sensitivity of lymphocytes to UV LIGHT exposure, and there must be some different culture condition(s) in the inducation of SCEs between human WBC and PLC but not in swine lymphocyte cultures. Since the BrdUrd/lymphocyte ratio of WBC was halved in PLC, the effect of BrdUrd concentration in inducing the SCE baseline frequency of PLC may be ruled out. Neither the cell separation technique nor polymorphonuclear leukocytes had a significant role in the elevated SCE frequency of human PLC or MLC. Experiments where human RBCs were titrated into human PLC showed that the induction of an elevated SCE frequency of PLC was suppressed in a dose-dependent manner by the presence of RBCs in the culture medium. Since the incorporation of pig or human RBCs into human PLC as well as into MLC reduced the SCE frequency to that of WBC, a common component and/or function existing in these cells is suggested. Analysis of different RBC components showed that RBCs, specifically RBC ghosts, release a diffusible but not dialyzable corrective factor into culture medium that is able to reduce the SCE frequencies of PLC

Meiosis-specific cohesin component, Stag3 is essential for maintaining centromere chromatid cohesion, and required for DNA repair and synapsis between homologous chromosomes.

Science.gov (United States)

Hopkins, Jessica; Hwang, Grace; Jacob, Justin; Sapp, Nicklas; Bedigian, Rick; Oka, Kazuhiro; Overbeek, Paul; Murray, Steve; Jordan, Philip W

2014-07-01

Cohesins are important for chromosome structure and chromosome segregation during mitosis and meiosis. Cohesins are composed of two structural maintenance of chromosomes (SMC1-SMC3) proteins that form a V-shaped heterodimer structure, which is bridged by a α-kleisin protein and a stromal antigen (STAG) protein. Previous studies in mouse have shown that there is one SMC1 protein (SMC1β), two α-kleisins (RAD21L and REC8) and one STAG protein (STAG3) that are meiosis-specific. During meiosis, homologous chromosomes must recombine with one another in the context of a tripartite structure known as the synaptonemal complex (SC). From interaction studies, it has been shown that there are at least four meiosis-specific forms of cohesin, which together with the mitotic cohesin complex, are lateral components of the SC. STAG3 is the only meiosis-specific subunit that is represented within all four meiosis-specific cohesin complexes. In Stag3 mutant germ cells, the protein level of other meiosis-specific cohesin subunits (SMC1β, RAD21L and REC8) is reduced, and their localization to chromosome axes is disrupted. In contrast, the mitotic cohesin complex remains intact and localizes robustly to the meiotic chromosome axes. The instability of meiosis-specific cohesins observed in Stag3 mutants results in aberrant DNA repair processes, and disruption of synapsis between homologous chromosomes. Furthermore, mutation of Stag3 results in perturbation of pericentromeric heterochromatin clustering, and disruption of centromere cohesion between sister chromatids during meiotic prophase. These defects result in early prophase I arrest and apoptosis in both male and female germ cells. The meiotic defects observed in Stag3 mutants are more severe when compared to single mutants for Smc1β, Rec8 and Rad21l, however they are not as severe as the Rec8, Rad21l double mutants. Taken together, our study demonstrates that STAG3 is required for the stability of all meiosis-specific cohesin

Meiosis-specific cohesin component, Stag3 is essential for maintaining centromere chromatid cohesion, and required for DNA repair and synapsis between homologous chromosomes.

Directory of Open Access Journals (Sweden)

Jessica Hopkins

2014-07-01

Full Text Available Cohesins are important for chromosome structure and chromosome segregation during mitosis and meiosis. Cohesins are composed of two structural maintenance of chromosomes (SMC1-SMC3 proteins that form a V-shaped heterodimer structure, which is bridged by a α-kleisin protein and a stromal antigen (STAG protein. Previous studies in mouse have shown that there is one SMC1 protein (SMC1β, two α-kleisins (RAD21L and REC8 and one STAG protein (STAG3 that are meiosis-specific. During meiosis, homologous chromosomes must recombine with one another in the context of a tripartite structure known as the synaptonemal complex (SC. From interaction studies, it has been shown that there are at least four meiosis-specific forms of cohesin, which together with the mitotic cohesin complex, are lateral components of the SC. STAG3 is the only meiosis-specific subunit that is represented within all four meiosis-specific cohesin complexes. In Stag3 mutant germ cells, the protein level of other meiosis-specific cohesin subunits (SMC1β, RAD21L and REC8 is reduced, and their localization to chromosome axes is disrupted. In contrast, the mitotic cohesin complex remains intact and localizes robustly to the meiotic chromosome axes. The instability of meiosis-specific cohesins observed in Stag3 mutants results in aberrant DNA repair processes, and disruption of synapsis between homologous chromosomes. Furthermore, mutation of Stag3 results in perturbation of pericentromeric heterochromatin clustering, and disruption of centromere cohesion between sister chromatids during meiotic prophase. These defects result in early prophase I arrest and apoptosis in both male and female germ cells. The meiotic defects observed in Stag3 mutants are more severe when compared to single mutants for Smc1β, Rec8 and Rad21l, however they are not as severe as the Rec8, Rad21l double mutants. Taken together, our study demonstrates that STAG3 is required for the stability of all meiosis

Comparison of 6-thioguanine-resistant mutation and sister chromatid exchanges in Chinese hamster V79 cells with forty chemical and physical agents

International Nuclear Information System (INIS)

Nishi, Y.; Hasegawa, M.M.; Taketomi, M.; Ohkawa, Y.; Inui, N.

1984-01-01

The induction of sister chromatid exchanges (SCE) and mutation at the hypoxanthine-guanine phosphoribosyl transferase locus and toxicities of 40 different chemical and physical agents were examined on Chinese hamster V79 cells. These agents included mono-, di-, tri-, and polyfunctional alkylating agents, intercalators, gamma-rays, and UV light irradiation. Mutation was measured as resistance to 6-thioguanine and toxicity as loss of cell-plating efficiency. SCE were examined 29 hr after treatment. With the agents examined, a highly positive correlation existed between SCE-inducing and mutagenic potencies, when expressed as increase in the number per a unit dose over the control values. But the great difference of the ratios of mutagenic potencies versus SCE-inducing potencies among agents was observed, the maximal difference in the ratios being about 200-fold. The agents that showed the higher values of the ratio (agents producing more mutations than SCE) were bleomycin, cobalt-60 gamma-rays, all ethylating agents (N-ethyl-N-nitrosourea, N-ethyl-N'-nitro-N-nitrosoguanidine, ethyl methanesulfonate, and diethylsulfate), N-propyl-N-nitrosourea, N-butyl-N-nitrosourea, isopropyl methanesulfonate, intercalating acridine compounds (2-methoxy-6-chloro-9-[3-(ethyl-2-chloroethyl)aminopropylamino]-acridine X 2HCl and 2-methoxy-6-chloro-9-[3-(chloroethyl)-aminopropylamino]acridine 2HCl) and UV light at 254 nm

Homologous recombination, sister chromatid cohesion, and chromosome condensation in mammalian meiosis

NARCIS (Netherlands)

Eijpe, M.

2002-01-01

In the life cycle of sexually reproducing eukaryotes, haploid and diploid generations of cells alternate. Two types of cell division occur in such a life cycle: mitosis and meiosis. They are compared in chapter 1 . Haploid and

Excision and crosslink repair of DNA and sister chromatid exchanges in cultured human fibroblasts with different repair capacities

Energy Technology Data Exchange (ETDEWEB)

Fujiwara, Y; Kano, Y; Paul, P; Goto, K; Yamamoto, K [Kobe Univ. (Japan). School of Medicine

1981-01-01

Xeroderma pigmentosum (XP) groups A to G lacked the initial stage of ultraviolet (UV) excision repair in the order of A = G > C > D > E asymptotically equals F, while the XP variant was weakly defective in the later repair steps. Killing sensitivities were in the orders of A >= G > D > C > E asymptotically equals F asymptotically equals variant > normal to UV, A = G > D > F > C = E > variant > normal to 4-nitroquinoline-1-oxide (4NQO), and A > C > D = E = F = variant > G = normal to decarbamoyl mitomycin-C(DCMC). The induced sister chromatid exchange (SCE) frequency was unrelated to the extent of repair deficiency. The SCE induction rate was consistently 3 - 6 fold higher by these UV-like mutagens in XP group A cells than in normal cells. However, repair-proficient Cockayne's syndrome (CS) cells showed a higher SCE induction by UV, which was normalized by NAD/sup +/, suggesting that chromatin lesions as well as DNA damage contribute to SCE. Two-step crosslink repair involves a first rapid half-excision and a second slow nucleotide-excision repair. Fanconi's anemia (FA) cells had an impaired first half-excision and were supersensitive to MC, but not to UV and DCMC. The SCE frequency induced by MC (1 hr) was higher in FA cells than in normal cells despite their normal response to DCMC, and vice versa in XP cells. FA cells lacked the first rapid decline and showed higher remaining SCEs. Thus, part of the crosslink seems to lead to SCE formation. Caffeine synergistically elevated UV-induced SCEs, but not UV induced mutations in V79 cells, implying that SCE may not necessarily involve mutation.

Excision and crosslink repair of DNA and sister chromatid exchanges in cultured human fibroblasts with different repair capacities

International Nuclear Information System (INIS)

Fujiwara, Yoshisada; Kano, Yoshio; Paul, P.; Goto, Kaoru; Yamamoto, Kazuo

1981-01-01

Xeroderma pigmentosum (XP) groups A to G lacked the initial stage of ultraviolet (UV) excision repair in the order of A = G > C > D > E asymptotically equals F, while the XP variant was weakly defective in the later repair steps. Killing sensitivities were in the orders of A >= G > D > C > E asymptotically equals F asymptotically equals variant > normal to UV, A = G > D > F > C = E > variant > normal to 4-nitroquinoline-1-oxide (4NQO), and A > C > D = E = F = variant > G = normal to decarbamoyl mitomycin-C(DCMC). The induced sister chromatid exchange (SCE) frequency was unrelated to the extent of repair deficiency. The SCE induction rate was consistently 3 - 6 fold higher by these UV-like mutagens in XP group A cells than in normal cells. However, repair-proficient Cockayne's syndrome (CS) cells showed a higher SCE induction by UV, which was normalized by NAD + , suggesting that chromatin lesions as well as DNA damage contribute to SCE. Two-step crosslink repair involves a first rapid half-excision and a second slow nucleotide-excision repair. Fanconi's anemia (FA) cells had an impaired first half-excision and were supersensitive to MC, but not to UV and DCMC. The SCE frequency induced by MC (1 hr) was higher in FA cells than in normal cells despite their normal response to DCMC, and vice versa in XP cells. FA cells lacked the first rapid decline and showed higher remaining SCEs. Thus, part of the crosslink seems to lead to SCE formation. Caffeine synergistically elevated UV-induced SCEs, but not UV induced mutations in V79 cells, implying that SCE may not necessarily involve mutation. (J.P.N.)

Excision and crosslink repair of DNA and sister chromatid exchanges in cultured human fibroblasts with different repair capacities

Energy Technology Data Exchange (ETDEWEB)

Fujiwara, Y.; Kano, Y.; Paul, P.; Goto, K.; Yamamoto, K. (Kobe Univ. (Japan). School of Medicine)

1981-01-01

Xeroderma pigmentosum (XP) groups A to G lacked the initial stage of ultraviolet (UV) excision repair in the order of A = G > C > D > E asymptotically equals F, while the XP variant was weakly defective in the later repair steps. Killing sensitivities were in the orders of A >= G > D > C > E asymptotically equals F asymptotically equals variant > normal to UV, A = G > D > F > C = E > variant > normal to 4-nitroquinoline-1-oxide (4NQO), and A > C > D = E = F = variant > G = normal to decarbamoyl mitomycin-C(DCMC). The induced sister chromatid exchange (SCE) frequency was unrelated to the extent of repair deficiency. The SCE induction rate was consistently 3 - 6 fold higher by these UV-like mutagens in XP group A cells than in normal cells. However, repair-proficient Cockayne's syndrome (CS) cells showed a higher SCE induction by UV, which was normalized by NAD/sup +/, suggesting that chromatin lesions as well as DNA damage contribute to SCE. Two-step crosslink repair involves a first rapid half-excision and a second slow nucleotide-excision repair. Fanconi's anemia (FA) cells had an impaired first half-excision and were supersensitive to MC, but not to UV and DCMC. The SCE frequency induced by MC (1 hr) was higher in FA cells than in normal cells despite their normal response to DCMC, and vice versa in XP cells. FA cells lacked the first rapid decline and showed higher remaining SCEs. Thus, part of the crosslink seems to lead to SCE formation. Caffeine synergistically elevated UV-induced SCEs, but not UV induced mutations in V79 cells, implying that SCE may not necessarily involve mutation.

Repairability during G 1 phase of inducting lesions of sister chromatid exchange produced by mitomycin C in salivary gland cells of mice In Vivo

International Nuclear Information System (INIS)

Cruz Vallejo, V.L.

1991-01-01

The repairability of the injuries that lead to the formation of sister chromatid exchange (SCE) produced by mitomycin C (MMC) with a dose of 2.1 mg/g in vivo, during the G 1 phase in the first cycle of cellular division (before the incorporation of BrdU [5-bromo-2 deoxyurine] to the DNA), as well as during the G 1 phase of the second cycle of cellular division (after the incorporation of BrdU) were analyzed. A 35.1% decrease in the frequency of SCE produced by Mitomycin C was observed, in the early G 1 phase of the first division, with respect to the frequency of SCE induced in the later G 1 phase. When Mitomycin C is given to cells whose DNA is substituted with BrdU in only one of the chain's filaments such decrease is not observed. The results suggest that the injuries caused by MMC, which give place to the SCE, in cells of the salivary glands of the mouse in vivo, are partially repaired only when induced in DNA which has not been substituted with BrdU. (Author)

Sister chromatid exchanges in the bone marrow cells of in vivo rats induced by gamma radiation and chemical mutagens

International Nuclear Information System (INIS)

Rodriguez R, R.G.

1981-01-01

Sister chromatid exchanges (SCE) in the bone marrow of in vivo rats induced by gamma radiation doses and by the chemical mutagens, mitomycin C (MMC), cyclophosphamide (CP), and sulphonate-methylmethane (SMM), were studied. The purpose was to evaluate the sensitivity and reproducibility of a simplified SCE in vivo detecting system developed in our laboratory and to compare the results obtained with those reported elsewhere. Simplification consisted in administering the amounts of 5-bromo-2'-deoxyuridine (BrdU) necessary to observe the SCE, after first adsorbing the BrdU in activated carbon and then injecting it interperitoneally, into the rats. The results were a longer time in vivo ADN incorporation without convulsions in the rats, and a reduction in the time course as compared to other methods. We observed a basal rate of 3.6+-0.37 SCE/cell and that: 0.44 Gy of gamma radiation induced 7.7+-0.73 SCE/cell; 1.6 μg/g of MMC induced 8.1+-1.20 SCE/cell; 5 μg/g of CP induced 8.25+-1.5 SCE/cell, 40 μg/g of SMM induced 22.0+-5 SCE/cell and 380 μg/g of sulphonate-ethylmethane induced 8.6+-1.2 SCE/cell. This showed that all the agents were capable of inducing SCE in the bone marrow cells of rats in vivo under our conditions. We noted a greater induced efficiency for gamma radiation than the obtained by other investigators and a relatively similar efficiency in the case of chemical mutagens as reported in other studies. (author)

Left-right symmetry breaking in mice by left-right dynein may occur via a biased chromatid segregation mechanism, without directly involving the Nodal gene

Energy Technology Data Exchange (ETDEWEB)

Sauer, Stephan; Klar, Amar J. S., E-mail: sauers@mail.nih.gov, E-mail: klara@mail.nih.gov [Gene Regulation and Chromosome Biology Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD (United States)

2012-11-16

Ever since cloning the classic iv (inversedviscerum) mutation identified the “left-right dynein” (lrd) gene in mice, most research on body laterality determination has focused on its function in motile cilia at the node embryonic organizer. This model is attractive, as it links chirality of cilia architecture to asymmetry development. However, lrd is also expressed in blastocysts and embryonic stem cells, where it was shown to bias the segregation of recombined sister chromatids away from each other in mitosis. These data suggested that lrd is part of a cellular mechanism that recognizes and selectively segregates sister chromatids based on their replication history: old “Watson” versus old “Crick” strands. We previously proposed that the mouse left-right axis is established via an asymmetric cell division prior to/or during gastrulation. In this model, left-right dynein selectively segregates epigenetically differentiated sister chromatids harboring a hypothetical “left-right axis development 1” (“lra1”) gene during the left-right axis establishing cell division. Here, asymmetry development would be ultimately governed by the chirality of the cytoskeleton and the DNA molecule. Our model predicts that randomization of chromatid segregation in lrd mutants should produce embryos with 25% situs solitus, 25% situs inversus, and 50% embryonic death due to heterotaxia and isomerism. Here we confirmed this prediction by using two distinct lrd mutant alleles. Other than lrd, thus far Nodal gene is the most upstream function implicated in visceral organs laterality determination. We next tested whether the Nodal gene constitutes the lra1 gene hypothesized in the model by testing mutant’s effect on 50% embryonic lethality observed in lrd mutants. Since Nodal mutation did not suppress lethality, we conclude that Nodal is not equivalent to the lra1 gene. In summary, we describe the origin of 50% lethality in lrd mutant mice not yet explained by any other

Left-right symmetry breaking in mice by left-right dynein may occur via a biased chromatid segregation mechanism, without directly involving the Nodal gene

International Nuclear Information System (INIS)

Sauer, Stephan; Klar, Amar J. S.

2012-01-01

Ever since cloning the classic iv (inversedviscerum) mutation identified the “left-right dynein” (lrd) gene in mice, most research on body laterality determination has focused on its function in motile cilia at the node embryonic organizer. This model is attractive, as it links chirality of cilia architecture to asymmetry development. However, lrd is also expressed in blastocysts and embryonic stem cells, where it was shown to bias the segregation of recombined sister chromatids away from each other in mitosis. These data suggested that lrd is part of a cellular mechanism that recognizes and selectively segregates sister chromatids based on their replication history: old “Watson” versus old “Crick” strands. We previously proposed that the mouse left-right axis is established via an asymmetric cell division prior to/or during gastrulation. In this model, left-right dynein selectively segregates epigenetically differentiated sister chromatids harboring a hypothetical “left-right axis development 1” (“lra1”) gene during the left-right axis establishing cell division. Here, asymmetry development would be ultimately governed by the chirality of the cytoskeleton and the DNA molecule. Our model predicts that randomization of chromatid segregation in lrd mutants should produce embryos with 25% situs solitus, 25% situs inversus, and 50% embryonic death due to heterotaxia and isomerism. Here we confirmed this prediction by using two distinct lrd mutant alleles. Other than lrd, thus far Nodal gene is the most upstream function implicated in visceral organs laterality determination. We next tested whether the Nodal gene constitutes the lra1 gene hypothesized in the model by testing mutant’s effect on 50% embryonic lethality observed in lrd mutants. Since Nodal mutation did not suppress lethality, we conclude that Nodal is not equivalent to the lra1 gene. In summary, we describe the origin of 50% lethality in lrd mutant mice not yet explained by any other

Left-right symmetry breaking in mice by left-right dynein may occur via a biased chromatid segregation mechanism, without directly involving the Nodal gene

Directory of Open Access Journals (Sweden)

Stephan eSauer

2012-11-01

Full Text Available Ever since cloning the classic iv mutation identified the ‘left-right dynein’ (lrd gene in mice, most research on body laterality determination has focused on its function in motile cilia at the node embryonic organizer. This model is attractive, as it links chirality of cilia architecture to asymmetry development. However, lrd is also expressed in blastocysts and embryonic stem cells, where it was shown to bias the segregation of recombined sister chromatids away from each other in mitosis. These data suggested that lrd is part of a cellular mechanism that recognizes and selectively segregates sister chromatids based on their replication history: old ‘Watson’ vs. old ‘Crick’ strands. We previously proposed that the mouse left-right axis is established via an asymmetric cell division prior to/or during gastrulation. In this model, left-right dynein selectively segregates epigenetically differentiated sister chromatids harboring a hypothetical ‘left-right axis development 1’ (‘lra1’ gene during the left-right axis establishing cell division. Here, asymmetry development would be ultimately governed by the chirality of the cytoskeleton and the DNA molecule. Our model predicts that randomization of chromatid segregation in lrd mutants should produce embryos with 25% situs solitus, 25% situs inversus, and 50% embryonic death due to heterotaxia and isomerism. Here we confirmed this prediction by using two distinct lrd mutant alleles. Other than lrd, thus far Nodal gene is the most upstream function implicated in visceral organs laterality determination. We next tested whether the Nodal gene constitutes the lra1 gene hypothesized in the model by testing mutant’s effect on 50% embryonic lethality observed in lrd mutants. Since Nodal mutation did not suppress lethality, we conclude that Nodal is not equivalent to the lra1 gene. In summary, we describe the origin of 50% lethality in lrd mutant mice not yet explained by any other

Characterization of the enhancing effect of caffeine on sister-chromatid exchanges induced by ultraviolet radiation in excision-proficient xeroderma pigmentosum lymphoblastoid cells

International Nuclear Information System (INIS)

Thoda, Hiroko; Oikawa, Atsushi

1988-01-01

Cells of some excision-proficient xeroderma pigmentosum (XP) cell lines are highly sensitive to post-UV caffeine treatment in terms of sister-chromatid exchange (SCE) induction as well as cell lethality. In the present study, the authors conducted a detailed investigation of the enhancing effect of caffeine on SCE frequency induced by UV in excision-proficient XP cells, and obtained the following results. (1). Continuous post-UV treatment with 1mM caffeine markedly enhances UV-induced SCEs and such enhanced SCEs occur with similar frequency during either the 1st or the 2nd cell cycle in the presence of caffeine and 5-bromodeoxyuridine (BrdUrd). (2) The high sensitivity of the cells to post-UV caffeine treatment persists for at least 2 days after UV when irradiated cells are held in either the proliferating of the nonproliferating state prior to the addition of BrdUrd. (3) Caffeine exerts its effect on cells in S phase. The most likely explanation for our findings is as follows. In excision-proficient XP cells, the cause of SCE formation such as UV-induced lesions or resulting perturbations of DNA replication persists untill the 2nd round or more of post-UV DNA replication. If caffeine is given as post-UV treatment, such abnormalities may be amplified, resulting in a synergistic increase in SCE frequency. (author). 21 refs.; 4 figs.; 4 tabs

Cytotoxicity and genotoxicity of UVA irradiation in Chinese hamster ovary cells measured by specific locus mutations, sister chromatid exchanges and chromosome aberrations

International Nuclear Information System (INIS)

Lundgren, Karsten; Wulf, H.C.

1988-01-01

The increasing use of artificial UVA (320-400 nm) suntanning devices has brought attention to possible hazardous effects of UVA. In contrast with earlier studies, several groups recently have described that UVA possibly is mutagenic. We evaluate the genotoxic properties of broad band UVA using CHO cells and three different assays: specific locus (HGPRT) mutations, chromosome aberrations, and sister chromatid exchanges (SCEs). The UVA-source was an UVASUN 2000 S (Mutzhas), emitting UVA above 340 nm. The survival curve of the cells exhibited a shoulder up to 200 kJ/m 2 , that was followed by exponential killing at higher fluences. Mutations were induced linearly in the fluence range of 0-200 kJ/m 2 to a level seven fold higher than the spontaneous, followed by a decrease at fluences above 300 kJ/m 2 . Over the total range of tested fluences (0-300 kJ/m 2 ) a linear dose-response relationship was observed for UVA-induced SCEs. A significantly higher percentage of the cells showed chromosomes with aberrations at the higher levels of exposure (200, 300 and 400 kJ/m 2 ), but no dose response was demonstrated. Our results confirm recent findings showing that UVA is mutagenic in mammalian cells and suggest that UVA exposure may contribute to the total burden of genetic damage caused by exposure to ultraviolet light. (author)

Effects of a tumor promoter and an anti-promoter on spontaneous and UV-induced 6-thioguanine-resistant mutations and sister-chromatid exchanges in V79 Chinese hamster cells

International Nuclear Information System (INIS)

Fujiwara, Y.; Kano, Y.; Tatsumi, M.; Paul, P.

1980-01-01

The effects of a tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) and/or an anti-promoter antipain (protease inhibitor) on spontaneous and ultraviolet-induced sister-chromatid exchanges (SCEs) and 6-thioguanine-resistant (6TGsup(r)) recessive mutations were examined in V79 Chinese hamster cells in culture. TPA and/or antipain neither significantly altered base-line and UV-induced immediate SCE frequencies, nor decreased the level of delayed SCEs which persisted 6-7 days after irradiation. TPA and/or antipain appeared to enhance the recovery of UV-induced 6TGsup(r) colonies at the plateau expression phase despite non-mutagenicity by themselves and unaltered metabolic cooperation. Thus, the results conceivably imply that the 6TGsup(r)-recessive mutation expression, but not fixation, can be modulated at the cell level by TPA and/or antipain. Our results, together with the recent results of Loveday and Latt, may argue against the notion that TPA enhances the antipain-suppressible SCEs as an index of mitotic recombination in relevance with a tumor-promotion mechanism. (orig.)

Absence of SUN-domain protein Slp1 blocks karyogamy and switches meiotic recombination and synapsis from homologs to sister chromatids

Science.gov (United States)

Vasnier, Christelle; de Muyt, Arnaud; Zhang, Liangran; Tessé, Sophie; Kleckner, Nancy E.; Zickler, Denise; Espagne, Eric

2014-01-01

Karyogamy, the process of nuclear fusion is required for two haploid gamete nuclei to form a zygote. Also, in haplobiontic organisms, karyogamy is required to produce the diploid nucleus/cell that then enters meiosis. We identify sun like protein 1 (Slp1), member of the mid–Sad1p, UNC-84–domain ubiquitous family, as essential for karyogamy in the filamentous fungus Sordaria macrospora, thus uncovering a new function for this protein family. Slp1 is required at the last step, nuclear fusion, not for earlier events including nuclear movements, recognition, and juxtaposition. Correspondingly, like other family members, Slp1 localizes to the endoplasmic reticulum and also to its extensions comprising the nuclear envelope. Remarkably, despite the absence of nuclear fusion in the slp1 null mutant, meiosis proceeds efficiently in the two haploid “twin” nuclei, by the same program and timing as in diploid nuclei with a single dramatic exception: the normal prophase program of recombination and synapsis between homologous chromosomes, including loading of recombination and synaptonemal complex proteins, occurs instead between sister chromatids. Moreover, the numbers of recombination-initiating double-strand breaks (DSBs) and ensuing recombinational interactions, including foci of the essential crossover factor Homo sapiens enhancer of invasion 10 (Hei10), occur at half the diploid level in each haploid nucleus, implying per-chromosome specification of DSB formation. Further, the distribution of Hei10 foci shows interference like in diploid meiosis. Centromere and spindle dynamics, however, still occur in the diploid mode during the two meiotic divisions. These observations imply that the prophase program senses absence of karyogamy and/or absence of a homolog partner and adjusts the interchromosomal interaction program accordingly. PMID:25210014

Relationship of the demethylation of the DNA with the induction of the sister chromatid exchanges (SCE) In vivo

International Nuclear Information System (INIS)

Toribio E, E.

2005-01-01

The methylation of the DNA is an epigenetic modification that has an important paper in the regulation of the functionality of the genome of the organisms. It can be altered by demethylation processes, either natural or experimentally induced. The 5-azacytidine (Aza) is a compound that causes the demethylation of the DNA (dm-DNA), inducing with it, expression genic and increase in the frequency of the Sister Chromatid Exchange (SCE). The SCE is a genotoxicity indicator, caused by diverse mutagens and carcinogen. Since the biological meaning and the formation mechanism of this phenomenon has not been totally illustrious, the exploration of the relation between the dm-DNA and the induction of SCE, it could offer new knowledge to explain those queries. The purpose of this work was to study in cells of the mouse bone marrow In vivo, the effect of the Aza on the induction of SCE, based on two aspects: 1) dose answer and 2) the effectiveness of multiple exhibition. To six groups of three to five animals, they are administered Aza to dose of 5, 10, 15 or 20 mg/Kg of weight; in sharp or multiple form, previously to the bromodeoxyuridine supply and 24 h was sacrificed after this; 2 h after an injection with colchicine. Preparations of those metaphases were made, those which were dyed by means of a technique of fluorescence more Giemsa. It was observed that to sharp low dose, the Aza produced an increment in the frequency of SCE that although small it was proportional and statistically significant. To sharp and multiple high doses, the Aza doesn't cause additional increments of SCE, but if toxicity at cellular level and of individuals. It is concluded that a relationship exists between the dm-DNA and the induction of SCE. It is suggested that the total demethylation of the DNA causes 2 SCE/Cell in cells of the mouse bone marrow, or that the cytotoxicity prevents to evidence a bigger induction. (Author)

Resolving RAD51C function in late stages of homologous recombination

Directory of Open Access Journals (Sweden)

Kuznetsov Sergey G

2007-06-01

Full Text Available Abstract DNA double strand breaks are efficiently repaired by homologous recombination. One of the last steps of this process is resolution of Holliday junctions that are formed at the sites of genetic exchange between homologous DNA. Although various resolvases with Holliday junctions processing activity have been identified in bacteriophages, bacteria and archaebacteria, eukaryotic resolvases have been elusive. Recent biochemical evidence has revealed that RAD51C and XRCC3, members of the RAD51-like protein family, are involved in Holliday junction resolution in mammalian cells. However, purified recombinant RAD51C and XRCC3 proteins have not shown any Holliday junction resolution activity. In addition, these proteins did not reveal the presence of a nuclease domain, which raises doubts about their ability to function as a resolvase. Furthermore, oocytes from infertile Rad51C mutant mice exhibit precocious separation of sister chromatids at metaphase II, a phenotype that reflects a defect in sister chromatid cohesion, not a lack of Holliday junction resolution. Here we discuss a model to explain how a Holliday junction resolution defect can lead to sister chromatid separation in mouse oocytes. We also describe other recent in vitro and in vivo evidence supporting a late role for RAD51C in homologous recombination in mammalian cells, which is likely to be resolution of the Holliday junction.

Effect of interleukin-2 on cell proliferation, sister-chromatid exchange induction, and nuclear stress protein phosphorylation in PHA-stimulated Fischer 344 rat spleen lymphocytes: Modulation by 2-mercaptoethanol

Energy Technology Data Exchange (ETDEWEB)

Morris, S.M.; Aidoo, A.; Domon, O.E.; McGarrity, L.J.; Kodell, R.L.; Schol, H.M.; Hinson, W.G.; Pipkin, J.L.; Casciano, D.A. (National Center for Toxicological Research, Jefferson, AR (USA))

1990-01-01

The effect of interleukin-2 (IL-2) on cell proliferation, sister-chromatid exchange (SCE) frequency, and the phosphorylation of nuclear stress proteins was evaluated in phytohemagglutinin (PHA)-stimulated spleen lymphocytes isolated from Fischer 344 rats. In addition, the ability of 2-mercaptoethanol (2-ME) to modulate the induction of these biological responses was characterized. Cell proliferation, as measured by the mitotic index, increased significantly. The average generation time (AGT) did not respond to IL-2 in a concentration-dependent manner and decreased significantly. The number of SCE increased significantly from control frequencies, to frequencies of 18.5 to 21.5 SCE per cell as the concentration of IL-2 in the culture medium increased to 50 half-maximal units per ml. A reduction in SCE frequency was observed when cells were cultured with 20 {mu}M 2-ME and IL-2 compared to IL-2 alone. Three nuclear proteins, with relative molecular masses of approximately 13,000-18,000, 20,000, and 80,000, were phosphorylated in IL-2-exposed G{sub 1}-phase nuclei. Elicitation of these nuclear proteins in IL-2-exposed cells was not affected by exposure to 2-ME.

Variation in the human lymphocyte sister chromatid exchange frequency as a function of time: results of daily and twice-weekly sampling

Energy Technology Data Exchange (ETDEWEB)

Tucker, J.D.; Christensen, M.L.; Strout, C.L.; McGee, K.A.; Carrano, A.V.

1987-01-01

The variation in lymphocyte sister chromatid exchange (SCE) frequency was investigated in healthy nonsmokers who were not taking any medication. Two separate studies were undertaken. In the first, blood was drawn from four women twice a week for 8 weeks. These donors recorded the onset and termination of menstruation and times of illness. In the second study, blood was obtained from two women and two men for 5 consecutive days on two separate occasions initiated 14 days apart. Analysis of the mean SCE frequencies in each study indicated that significant temporal variation occurred in each donor, and that more variation occurred in the longer study. Some of the variation was found to be associated with the menstrual cycle. In the daily study, most of the variation appeared to be random, but occasional day-to-day changes occurred that were greater than those expected by chance. To determine how well a single SCE sample estimated the pooled mean for each donor in each study, the authors calculated the number of samples that encompassed that donor's pooled mean within 1 or more standard errors. For both studies, about 75% of the samples encompassed the pooled mean within 2 standard errors. An analysis of high-frequency cells (HFCs) was also undertaken. The results for each study indicate that the proportion of HFCs, compared with the use of Fisher's Exact test, is significantly more constant than the means, which were compared by using the t-test. These results coupled with our previous work suggest that HFC analysis may be the method of choice when analyzing data from human population studies.

DNA asymmetry in stem cells - immortal or mortal?

Science.gov (United States)

Yadlapalli, Swathi; Yamashita, Yukiko M

2013-09-15

The immortal strand hypothesis proposes that stem cells retain a template copy of genomic DNA (i.e. an 'immortal strand') to avoid replication-induced mutations. An alternative hypothesis suggests that certain cells segregate sister chromatids non-randomly to transmit distinct epigenetic information. However, this area of research has been highly controversial, with conflicting data even from the same cell types. Moreover, historically, the same term of 'non-random sister chromatid segregation' or 'biased sister chromatid segregation' has been used to indicate distinct biological processes, generating a confusion in the biological significance and potential mechanism of each phenomenon. Here, we discuss the models of non-random sister chromatid segregation, and we explore the strengths and limitations of the various techniques and experimental model systems used to study this question. We also describe our recent study on Drosophila male germline stem cells, where sister chromatids of X and Y chromosomes are segregated non-randomly during cell division. We aim to integrate the existing evidence to speculate on the underlying mechanisms and biological relevance of this long-standing observation on non-random sister chromatid segregation.

Influence of GSTM1 and GSTT1 genotypes and confounding factors on the frequency of sister chromatid exchange and micronucleus among road construction workers.

Science.gov (United States)

Kumar, Anil; Yadav, Anita; Giri, Shiv Kumar; Dev, Kapil; Gautam, Sanjeev Kumar; Gupta, Ranjan; Aggarwal, Neeraj

2011-07-01

In the present study, we have investigated the influence of polymorphism of GSTM1 and GSTT1 genes and confounding factors such as age, sex, exposure duration and consumption habits on cytogenetic biomarkers. Frequency of sister chromatid exchanges (SCEs), high frequency cell (HFC) and cytokinesis blocked micronuclei (CBMN) were evaluated in peripheral blood lymphocytes of 115 occupationally exposed road construction workers and 105 unexposed individuals. The distribution of null and positive genotypes of glutathione-S transferase gene was evaluated by multiplex PCR among control and exposed subjects. An increased frequency of CBMN (7.03±2.08); SCE (6.95±1.76) and HFC (6.28±1.69) were found in exposed subjects when compared to referent (CBMN - 3.35±1.10; SCE - 4.13±1.30 and HFC - 3.98±1.56). These results were found statistically significant at p<0.05. When the effect of confounding factors on the frequency of studied biomarkers was evaluated, a strong positive interaction was found. The individuals having GSTM1 and GSTT1 null genotypes had higher frequency of CBMN, SCE and HFC. The association between GSTM1 and GSTT1 genotypes and studied biomarkers was found statistically significant at p<0.05. Our findings suggest that individuals having null type of GST are more susceptible to cytogenetic damage by occupational exposure regardless of confounding factors. There is a significant effect of polymorphism of these genes on cytogenetic biomarkers which are considered as early effects of genotoxic carcinogens. Copyright © 2011 Elsevier Ltd. All rights reserved.

As to the clastogenic-, sister-chromatid exchange inducing-and cytotoxic activity of inosine triphosphate in cultures of human peripheral lymphocytes.

Science.gov (United States)

Vormittag, W; Brannath, W

2001-05-09

The influence of commercial inosine triphosphate (ITP) on the chromosome aberration rate, the mitotic rate, sister-chromatid exchange (SCE) frequency, and the proportion of first (X1), second (X2) and third (X3) division metaphases was investigated in 72h cultures of human peripheral lymphocytes. The blood donors had mild inactive arthrosis and a normal health check-up. All cultures of each volunteer were set-up simultaneously. In contrast to a previous report [Arch. Biochem. Biophys. 278 (1990) 238-244], it was demonstrated in two preliminary studies (number of subjects, n=5 each) that ITP at a final concentration of 100 microM does not induce chromosomal aberrations and, furthermore, that not ITP concentrations higher than 100 microM but ITP doses higher than 3.8mM prohibit culture growth. Based on these results, cultures with a final ITP concentration of 3.6mM (max.) and 1.8mM (max./2) were compared with control cultures (number of subjects n=10; three males and seven females, mean age x=57.6 years). Whereas no increase in the chromosomal breakage rate was observed in cultures with an ITP concentration of 1.8mM and only a marginally significant one (P=0.048) for 3.6mM ITP cultures, a highly significant induction of SCEs, not only at an ITP concentration of 3.6mM (Prate from 0 to 1.8mM as well as from 1.8 to 3.6mM in the aberration studies (all P values are equal to smallest possible one for a sample size of 10, namely, 0.002), and in the SCE studies there is a significant decrease in the X3 frequency when ITP is increased (0-1.8mM: P=0.0061 and 1.8-3.6mM: Pchanges significantly only at the second dose step (0-1.8mM ITP: P=0.22 and 1.8-3.6mM ITP: P<0.0001). The results are discussed.

Bub1 autophosphorylation feeds back to regulate kinetochore docking and promote localized substrate phosphorylation.

Science.gov (United States)

Asghar, Adeel; Lajeunesse, Audrey; Dulla, Kalyan; Combes, Guillaume; Thebault, Philippe; Nigg, Erich A; Elowe, Sabine

2015-09-24

During mitosis, Bub1 kinase phosphorylates histone H2A-T120 to promote centromere sister chromatid cohesion through recruitment of shugoshin (Sgo) proteins. The regulation and dynamics of H2A-T120 phosphorylation are poorly understood. Using quantitative phosphoproteomics we show that Bub1 is autophosphorylated at numerous sites. We confirm mitosis-specific autophosphorylation of a several residues and show that Bub1 activation is primed in interphase but fully achieved only in mitosis. Mutation of a single autophosphorylation site T589 alters kinetochore turnover of Bub1 and results in uniform H2A-T120 phosphorylation and Sgo recruitment along chromosome arms. Consequently, improper sister chromatid resolution and chromosome segregation errors are observed. Kinetochore tethering of Bub1-T589A refocuses H2A-T120 phosphorylation and Sgo1 to centromeres. Recruitment of the Bub1-Bub3-BubR1 axis to kinetochores has recently been extensively studied. Our data provide novel insight into the regulation and kinetochore residency of Bub1 and indicate that its localization is dynamic and tightly controlled through feedback autophosphorylation.

Evidence that cyclophosphamide can to induce exchanges in the sister chromatids (ICH) through secondary injuries; Evidencia de que la ciclofosfamida puede inducir intercambios en las cromatidas hermanas (ICH) a traves de lesiones secundarias

Energy Technology Data Exchange (ETDEWEB)

Morales R, P.; Rodriguez R, R. [Instituto Nacional de Investigaciones nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

1997-07-01

By means of the use of destination protocol of ICH inductive injuries (DLI-ICH), it was studied if interchanges in the sister chromatids (ICH) induced by cyclophosphamide (CP), in the second post-treatment division (ICH-2) are produced by secondary injuries or by fresh injuries. For discard between these possibilities it was administered CP at different periods before of the first post-treatment division, taking as reference the administered time for high dose of bromodeoxyuridine (BrdU ) which was approximately at the beginning of this division. The ICH frequencies that occur in the first, the second and the third synthesis stages (S) were determined. It was observed that when the administered CP was four hours before BrdU , the ICH frequencies of the second and the third S were reduced. The frequency of the first ICH increased lightly in relation to those of the normal protocol (0.5 h before BrdU ) and that the supplying of CP six hours before caused almost a total reduction of ICH of second and third S and an important increment of ICH of first S.This was interpreted as evidence that the ICH-2 are product of secondary injuries. (Author)

Strand-seq : A unifying tool for studies of chromosome segregation

NARCIS (Netherlands)

Falconer, Ester; Lansdorp, Peter M.

2013-01-01

Non random segregation of sister chromatids has been implicated to help specify daughter cell fate (the Silent Sister Hypothesis [1]) or to protect the genome of long-lived stem cells (the Immortal Strand Hypothesis [2]). The idea that sister chromatids are non-randomly segregated into specific

Modelling and testing the molecular mechanism of radiation-induced chromatid breaks

International Nuclear Information System (INIS)

Bryant, P. E.

2001-01-01

Chromatid breaks induced by ionizing radiation in the G2 phase of the cell cycle are considered as markers of individual human radiosensitivity and may indicate the presence of low-penetrance genes regulating susceptibility to breast and other cancers). Together with our own study of Scottish (Tayside) breast cancer patients and a group of normal controls these studies show an overall 10-fold variation in chromatid break frequency (the parameter defining individual chromosomal 'radiosensitivity'). Thus, an understanding of the mechanisms and genes involved in determining these widely different responses should help to clarify the reasons for individual radiosensitivity and may lead us to identify key genes involved in cancer susceptibility. The presence of colour-switches at around 16% of chromatid break points (detected in harlequin-stained chromosomes) indicates that this type of chromatid break is formed by a chromatin rearrangement involving one or more large chromatin domains of the order of 3 - 5 Mbp, possibly representing transcription 'factories'. The signal model of chromatid breaks assumes that all chromatid breaks are the result of chromatin rearrangements, and that the initiating DNA double-strand break (dsb) is itself not involved in the rearrangement but signals its presence (possibly via ATM protein or DNAPK) leading to the initiation of the chromatin rearrangement. Experimental evidence from radiosensitive cell lines (e.g. human AT and hamster irs2) and with the nucleoside analogue araA (9-β-D-arabinofuranosyladenine) demonstrates the lack of correspondence between the rejoining kinetics of dsb and that of disappearance of chromatid breaks, thus supporting the signal model. Coupled with the linear induction of chromatid breaks with dose in both human and rodent cell lines of various types, and the production of chromatid breaks by single dsb in genetically engineered cell lines the classical 'breakage-first' model of chromatid breaks is no longer

Arabidopsis thaliana WAPL is essential for the prophase removal of cohesin during meiosis.

Directory of Open Access Journals (Sweden)

Kuntal De

2014-07-01

Full Text Available Sister chromatid cohesion, which is mediated by the cohesin complex, is essential for the proper segregation of chromosomes in mitosis and meiosis. The establishment of stable sister chromatid cohesion occurs during DNA replication and involves acetylation of the complex by the acetyltransferase CTF7. In higher eukaryotes, the majority of cohesin complexes are removed from chromosomes during prophase. Studies in fly and human have shown that this process involves the WAPL mediated opening of the cohesin ring at the junction between the SMC3 ATPase domain and the N-terminal domain of cohesin's α-kleisin subunit. We report here the isolation and detailed characterization of WAPL in Arabidopsis thaliana. We show that Arabidopsis contains two WAPL genes, which share overlapping functions. Plants in which both WAPL genes contain T-DNA insertions show relatively normal growth and development but exhibit a significant reduction in male and female fertility. The removal of cohesin from chromosomes during meiotic prophase is blocked in Atwapl mutants resulting in chromosome bridges, broken chromosomes and uneven chromosome segregation. In contrast, while subtle mitotic alterations are observed in some somatic cells, cohesin complexes appear to be removed normally. Finally, we show that mutations in AtWAPL suppress the lethality associated with inactivation of AtCTF7. Taken together our results demonstrate that WAPL plays a critical role in meiosis and raises the possibility that mechanisms involved in the prophase removal of cohesin may vary between mitosis and meiosis in plants.

STAG2 and Rad21 mammalian mitotic cohesins are implicated in meiosis

OpenAIRE

Prieto, Ignacio; Pezzi, Nieves; Buesa, José M.; Kremer, Leonor; Barthelemy, Isabel; Carreiro, Candelas; Roncal, Fernando; Martínez, Alicia; Gómez, Lucio; Fernández, Raúl; Martínez-A, Carlos; Barbero, José L.

2002-01-01

STAG/SA proteins are specific cohesin complex subunits that maintain sister chromatid cohesion in mitosis and meiosis. Two members of this family, STAG1/SA1 and STAG2/SA2,‡ are classified as mitotic cohesins, as they are found in human somatic cells and in Xenopus laevis as components of the cohesinSA1 and cohesinSA2 complexes, in which the shared subunits are Rad21/SCC1, SMC1 and SMC3 proteins. A recently reported third family member, STAG3, is germinal cell-specific and is a subunit of the ...

The chromosome damage induced by x-ray radiation doses. Comparison between dicentric chromosomes, micronuclei and Sister Chromatid Exchanges analyses. Valoracion de dao cromosomico originado por una dosis de rayos X. Comparacion de los analisis de cromosomas dicentricos, micronucleos e intercambios entre cromatidas hermanas

Energy Technology Data Exchange (ETDEWEB)

Fernandez, J.L.; Losada, C.; Losada, G.; Veiras, C. (Centro Oncologico de Galicia. La Corua (Spain)); Goyanes, V.J. (Hospital ' ' Teresa Herrera' ' . La Corua (Spain))

1993-01-01

Exposure to ionizing radiations is a well-known source of chromosome damage. Here we present a comparison among three different methodologies employed to recognize cytogenetic damage, after an acute exposure of human lymphocytes to 3 Gy of X-rays (100kVp). Scoring of dicentric chromosomes, present in first mitosis ''in vitro'', was the method of preference as dicentrics increased 937.5 times with respect to background. Micronucleus scoring in binucleated-cytokinesis blocked cells showed an increase of 32.5 times, while it was only of 1.46 times when Sister Chromatid Exchanges (SCEs) were analyzed. The estimated probability of an acentric fragment becoming a micronucleus was around 0.25. Intercellular distribution of dicentrics agree with Poisson, while micronucleus were overdispersed. When analyzed at second cycle after damage induction, the dicentrics yield as well as the level of cells with unstable cromosome aberrations, decreased around a half. Finally, SCEs level was similar in cells with or without unstable structural chromosome aberrations. (Author)

The roles of cohesins in mitosis, meiosis, and human health and disease

Science.gov (United States)

Brooker, Amanda S.; Berkowitz, Karen M.

2015-01-01

Summary Mitosis and meiosis are essential processes that occur during development. Throughout these processes, cohesion is required to keep the sister chromatids together until their separation at anaphase. Cohesion is created by multi-protein subunit complexes called cohesins. Although the subunits differ slightly in mitosis and meiosis, the canonical cohesin complex is composed of four subunits that are quite diverse. The cohesin complexes are also important for DNA repair, gene expression, development, and genome integrity. Here we provide an overview of the roles of cohesins during these different events, as well as their roles in human health and disease, including the cohesinopathies. Although the exact roles and mechanisms of these proteins are still being elucidated, this review will serve as a guide for the current knowledge of cohesins. PMID:24906316

Mek1/Mre4 is a master regulator of meiotic recombination in budding yeast

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Nancy M. Hollingsworth

2016-02-01

Full Text Available Sexually reproducing organisms create gametes with half the somatic cell chromosome number so that fusion of gametes at fertilization does not change the ploidy of the cell. This reduction in chromosome number occurs by the specialized cell division of meiosis in which two rounds of chromosome segregation follow a single round of chromosome duplication. Meiotic crossovers formed between the non-sister chromatids of homologous chromosomes, combined with sister chromatid cohesion, physically connect homologs, thereby allowing proper segregation at the first meiotic division. Meiotic recombination is initiated by programmed double strand breaks (DSBs whose repair is highly regulated such that (1 there is a bias for recombination with homologs rather than sister chromatids, (2 crossovers are distributed throughout the genome by a process called interference, (3 crossover homeostasis regulates the balance between crossover and non-crossover repair to maintain a critical number of crossovers and (4 each pair of homologs receives at least one crossover. It was previously known that the imposition of interhomolog bias in budding yeast requires meiosis-specific modifications to the DNA damage response and the local activation of the meiosis-specific Mek1/Mre4 (hereafter Mek1 kinase at DSBs. However, because inactivation of Mek1 results in intersister, rather than interhomolog DSB repair, whether Mek1 had a role in interhomolog pathway choice was unknown. A recent study by Chen et al. (2015 reveals that Mek1 indirectly regulates the crossover/non-crossover decision between homologs as well as genetic interference. It does this by enabling phosphorylation of Zip1, the meiosis-specific transverse filament protein of the synaptonemal complex (SC, by the conserved cell cycle kinase, Cdc7-Dbf4 (DDK. These results suggest that Mek1 is a “master regulator” of meiotic recombination in budding yeast.

Sister chromatid exchanges and high-frequency cells in men environmentally and occupationally exposed to ambient air pollutants. An intergroup comparison with respect to seasonal changes and smoking habit

Energy Technology Data Exchange (ETDEWEB)

Pendzich, Joanna; Motykiewicz, Grazyna; Michalska, Jadwiga; Kostowska, Alina; Chorazy, Mieczyslaw [Department of Tumor Biology, Institute of Oncology, Gliwice (Poland); Wang, Li You [Graduate Institute of Epidemiology, College of Public Health, National Taiwan University, Taipei (Taiwan, Province of China)

1997-11-28

Sister chromatid exchanges (SCE) and high-frequency cells (HFC) were measured in peripheral blood lymphocytes from men environmentally and occupationally exposed to a mixture of ambient air pollutants. The environmentally exposed individuals were inhabitants of the industrial region of Upper Silesia; those occupationally exposed were Silesian cokery or steel plant workers, while the control group consisted of rural region residents. A total of 147 males were enrolled in the study. Blood samples were collected in winter (February) and summer (September) seasons. Three major areas were investigated during the study: exposure-based dose dependency, seasonal changes, and influence of smoking habits on the SCE frequencies. The latter is frequently reported as a confounding factor in SCE analyses. In both winter and summer samples, statistically significant increases of SCE were observed in the environmentally and occupationally exposed groups compared to the controls (p<0.001). The difference between both exposed groups was also significant (p<0.001). An intergroup comparison was based on ANOVA after adjustment for smoking status. In all three groups of interest, a seasonal variation was found with higher levels in winter. However, in a part of the study in which each donor served as his own control, statistical differences were only found within the exposed groups. Control region inhabitants did not have significantly higher frequencies of SCE in winter, compared to summer samples. The impact of two major confounders, age of the donor and smoking habit, was investigated by multiple regression analysis. Smoking was a major factor influencing the level of SCE. Nevertheless, the effect was seen in winter samples only, which suggests an additive response and adds new information to this known effect

G2-chromatid breaks and rejoining in HO8910 cells induced by γ-rays

International Nuclear Information System (INIS)

Wang Zhuanzi; Liu Bing; Duan Xin

2006-01-01

The premature chromosome condensation technique was used to estimate the dosage effect on the G2-chromosome breaks in HO8910 after exposure to γ-rays, and to investigate the time effect on the rejoining of the G2-chromosome breaks. The results show that the number of G2 chromatid-type breaks linearly increased with doses and the number of G2 iso-chromatid breaks increased with dose in a linear-square manner. With the prolongation of culture time, G2 chromatid-type breaks obviously got repaired, and almost 65% chromatid-type breaks got repaired in the early 24 hour post-irradiation, whereas only about 20% iso-chromatid breaks got repaired during the same time. Furthermore, the rejoining of the two types of chromatid breaks occurred mostly in 2 hours after irradiation and from 12 to 24 hours after irradiation, the number of chromatid breaks was found to get stabilized basically, which indicates that the repairing process is over in the early 24 hours of post-irradiation. (authors)

Towards a Cohesive Theory of Cohesion

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Janet McLeod

2013-12-01

Full Text Available Conventional wisdom suggests that group cohesion is strongly related to performance. This may be based on the notion that better cohesion leads to the sharing of group goals. However, empirical and meta-analytic studies have been unable to consistently demonstrate a relationship between cohesion and performance. Partially, this problem could be attributed to the disagreement on the precise definition of cohesion and its components. Further, when the cohesion construct is evaluated under Cohen’s Cumulative Research Program (CRP, it is surprisingly found to belong to the category of early-to-intermediate stage of theory development. Therefore, a thorough re-examination of the cohesion construct is essential to advance our understanding of the cohesion-productivity relationship. We propose a qualitative approach because it will help establish the definitions, enable us to better test our theories about cohesion and its moderators, and provide insights into how best to enlist cohesion to improve team performance.

Chiasmatic and achiasmatic inverted meiosis of plants with holocentric chromosomes

Science.gov (United States)

Cabral, Gabriela; Marques, André; Schubert, Veit; Pedrosa-Harand, Andrea; Schlögelhofer, Peter

2014-01-01

Meiosis is a specialized cell division in sexually reproducing organisms before gamete formation. Following DNA replication, the canonical sequence in species with monocentric chromosomes is characterized by reductional segregation of homologous chromosomes during the first and equational segregation of sister chromatids during the second meiotic division. Species with holocentric chromosomes employ specific adaptations to ensure regular disjunction during meiosis. Here we present the analysis of two closely related plant species with holocentric chromosomes that display an inversion of the canonical meiotic sequence, with the equational division preceding the reductional. In-depth analysis of the meiotic divisions of Rhynchospora pubera and R. tenuis reveals that during meiosis I sister chromatids are bi-oriented, display amphitelic attachment to the spindle and are subsequently separated. During prophase II, chromatids are connected by thin chromatin threads that appear instrumental for the regular disjunction of homologous non-sister chromatids in meiosis II. PMID:25295686

Strand-seq: A unifying tool for studies of chromosome segregation

OpenAIRE

Falconer, Ester; Lansdorp, Peter M.

2013-01-01

Non random segregation of sister chromatids has been implicated to help specify daughter cell fate (the Silent Sister Hypothesis [1]) or to protect the genome of long-lived stem cells (the Immortal Strand Hypothesis [2]). The idea that sister chromatids are non-randomly segregated into specific daughter cells is only marginally supported by data in sporadic and often contradictory studies. As a result, the field has moved forward rather slowly. The advent of being able to directly label and d...

Characterization of muntjac DNA

International Nuclear Information System (INIS)

Davis, R.C.

1981-01-01

Sister chromatid exchange (SCE) in muntjac chromosomes is generally proportional to the chromosomal DNA content, but the SCE frequency is reduced in the heterochromatic neck region of the X chromosome. The physical properties of muntjac DNA and the kinetics of repair of UV damage in muntjac heterochromatin and euchromatin were examined and compared with the distribution of sister chromatid exchange

Characterization of muntjac DNA

Energy Technology Data Exchange (ETDEWEB)

Davis, R.C.

1981-05-27

Sister chromatid exchange (SCE) in muntjac chromosomes is generally proportional to the chromosomal DNA content, but the SCE frequency is reduced in the heterochromatic neck region of the X chromosome. The physical properties of muntjac DNA and the kinetics of repair of UV damage in muntjac heterochromatin and euchromatin were examined and compared with the distribution of sister chromatid exchange.

Baseline frequency of chromosomal aberrations and sister chromatid exchanges in peripheral blood lymphocytes of healthy individuals living in Turin (North-Western Italy): assessment of the effects of age, sex and GSTs gene polymorphisms on the levels of genomic damage.

Science.gov (United States)

Santovito, Alfredo; Cervella, Piero; Delpero, Massimiliano

2016-05-01

The increased exposure to environmental pollutants has led to the awareness of the necessity for constant monitoring of human populations, especially those living in urban areas. This study evaluated the background levels of genomic damage in a sample of healthy subjects living in the urban area of Turin (Italy). The association between DNA damage with age, sex and GSTs polymorphisms was assessed. One hundred and one individuals were randomly sampled. Sister Chromatid Exchanges (SCEs) and Chromosomal Aberrations (CAs) assays, as well as genotyping of GSTT1 and GSTM1 genes, were performed. Mean values of SCEs and CAs were 5.137 ± 0.166 and 0.018 ± 0.002, respectively. Results showed age and gender associated with higher frequencies of these two cytogenetic markers. The eldest subjects (51-65 years) showed significantly higher levels of genomic damage than younger individuals. GSTs polymorphisms did not appear to significantly influence the frequencies of either markers. The CAs background frequency observed in this study is one of the highest reported among European populations. Turin is one of the most polluted cities in Europe in terms of air fine PM10 and ozone and the clastogenic potential of these pollutants may explain the high frequencies of chromosomal rearrangements reported here.

APC/C-Cdc20 mediates deprotection of centromeric cohesin at meiosis II in yeast.

Science.gov (United States)

Jonak, Katarzyna; Zagoriy, Ievgeniia; Oz, Tugce; Graf, Peter; Rojas, Julie; Mengoli, Valentina; Zachariae, Wolfgang

2017-06-18

Cells undergoing meiosis produce haploid gametes through one round of DNA replication followed by 2 rounds of chromosome segregation. This requires that cohesin complexes, which establish sister chromatid cohesion during S phase, are removed in a stepwise manner. At meiosis I, the separase protease triggers the segregation of homologous chromosomes by cleaving cohesin's Rec8 subunit on chromosome arms. Cohesin persists at centromeres because the PP2A phosphatase, recruited by the shugoshin protein, dephosphorylates Rec8 and thereby protects it from cleavage. While chromatids disjoin upon cleavage of centromeric Rec8 at meiosis II, it was unclear how and when centromeric Rec8 is liberated from its protector PP2A. One proposal is that bipolar spindle forces separate PP2A from Rec8 as cells enter metaphase II. We show here that sister centromere biorientation is not sufficient to "deprotect" Rec8 at meiosis II in yeast. Instead, our data suggest that the ubiquitin-ligase APC/C Cdc20 removes PP2A from centromeres by targeting for degradation the shugoshin Sgo1 and the kinase Mps1. This implies that Rec8 remains protected until entry into anaphase II when it is phosphorylated concurrently with the activation of separase. Here, we provide further support for this model and speculate on its relevance to mammalian oocytes.

The mitosis-regulating and protein-protein interaction activities of astrin are controlled by aurora-A-induced phosphorylation.

Science.gov (United States)

Chiu, Shao-Chih; Chen, Jo-Mei Maureen; Wei, Tong-You Wade; Cheng, Tai-Shan; Wang, Ya-Hui Candice; Ku, Chia-Feng; Lian, Chiao-Hsuan; Liu, Chun-Chih Jared; Kuo, Yi-Chun; Yu, Chang-Tze Ricky

2014-09-01

Cells display dramatic morphological changes in mitosis, where numerous factors form regulatory networks to orchestrate the complicated process, resulting in extreme fidelity of the segregation of duplicated chromosomes into two daughter cells. Astrin regulates several aspects of mitosis, such as maintaining the cohesion of sister chromatids by inactivating Separase and stabilizing spindle, aligning and segregating chromosomes, and silencing spindle assembly checkpoint by interacting with Src kinase-associated phosphoprotein (SKAP) and cytoplasmic linker-associated protein-1α (CLASP-1α). To understand how Astrin is regulated in mitosis, we report here that Astrin acts as a mitotic phosphoprotein, and Aurora-A phosphorylates Astrin at Ser(115). The phosphorylation-deficient mutant Astrin S115A abnormally activates spindle assembly checkpoint and delays mitosis progression, decreases spindle stability, and induces chromosome misalignment. Mechanistic analyses reveal that Astrin phosphorylation mimicking mutant S115D, instead of S115A, binds and induces ubiquitination and degradation of securin, which sequentially activates Separase, an enzyme required for the separation of sister chromatids. Moreover, S115A fails to bind mitosis regulators, including SKAP and CLASP-1α, which results in the mitotic defects observed in Astrin S115A-transfected cells. In conclusion, Aurora-A phosphorylates Astrin and guides the binding of Astrin to its cellular partners, which ensures proper progression of mitosis. Copyright © 2014 the American Physiological Society.

Mammalian ChlR1 has a role in heterochromatin organization

International Nuclear Information System (INIS)

Inoue, Akira; Hyle, Judith; Lechner, Mark S.; Lahti, Jill M.

2011-01-01

The ChlR1 DNA helicase, encoded by DDX11 gene, which is responsible for Warsaw breakage syndrome (WABS), has a role in sister-chromatid cohesion. In this study, we show that human ChlR1 deficient cells exhibit abnormal heterochromatin organization. While constitutive heterochromatin is discretely localized at perinuclear and perinucleolar regions in control HeLa cells, ChlR1-depleted cells showed dispersed localization of constitutive heterochromatin accompanied by disrupted centromere clustering. Cells isolated from Ddx11 -/- embryos also exhibited diffuse localization of centromeres and heterochromatin foci. Similar abnormalities were found in HeLa cells depleted of combinations of HP1α and HP1β. Immunofluorescence and chromatin immunoprecipitation showed a decreased level of HP1α at pericentric regions in ChlR1-depleted cells. Trimethyl-histone H3 at lysine 9 (H3K9-me3) was also modestly decreased at pericentric sequences. The abnormality in pericentric heterochromatin was further supported by decreased DNA methylation within major satellite repeats of Ddx11 -/- embryos. Furthermore, micrococcal nuclease (MNase) assay revealed a decreased chromatin density at the telomeres. These data suggest that in addition to a role in sister-chromatid cohesion, ChlR1 is also involved in the proper formation of heterochromatin, which in turn contributes to global nuclear organization and pleiotropic effects. -- Highlights: → New role for ChlR1 (DDX11), a cohesinopathy gene, in heterochromatin organization. → Loss of ChlR1 altered heterochromatin localization and centromere clustering. → Reduced ChlR1 levels also reduced HP1α and H3K9-me3 binding to pericentric DNA. → Decreased DNA methylation was found in pericentric repeats of Ddx11 -/- embryos. → These findings will aid in understanding the pathogenesis of Warsaw breakage syndrome.

Effect of chlorophyllin on induction of exchanges in sister chromatids by gamma irradiation in mice spermatogonia in vivo; Efecto de la clorofilina sobre la induccion de intercambios en las cromatidas hermanas (ICH) por radiacion gamma en espermatogonias de raton In vivo

Energy Technology Data Exchange (ETDEWEB)

Mendiola C, M T

1994-12-31

Mouse were exposed to different doses of gamma radiation and the effect on Sister Chromatid Exchange (SCE) frequency in spermatogonias was evaluated. The effect was analyzed before and after Bromodeoxyuridine (BrdU) incorporation to determine the interference of such agent with the cellular response induced by radiation. The capacity of chlorophyllin (sodium and Copper salt derivative from chlorophyll) to reduce SCE induction by radiation in normal and BrdU radio sensitized spermatogonia was also determined. The results indicate that there was a significant increase in SCE frequency by gamma radiation exposure in these cells, such effect was higher irradiating after BrdU incorporation than before. This fact confirms previous observations that BrdU sensitizes some cells to SCE induction. With regard to the chlorophyllin effect, it was determined that this salt acts as a radioprotector reducing gamma-rays induced SCE before or after BrdU incorporation Total protection was obtained with 200 {mu}g of chlorophyllin per g of body weight in both protocols. Under the experimental conditions this study there was no evidence of genotoxicity induced by chlorophyllin itself. The results suggest that this agent may act as a radioprotector by scavenging free radicals produced by gamma-radiation which cause DNA lesions that are involved in SCE formation. (Author).

Sisters Hope

DEFF Research Database (Denmark)

Lawaetz, Anna; Worre Hallberg, Gry

2011-01-01

Sisters Hope invites young scholars to visit our elite-school for run-away youngsters. Maybe you will be the next one to be collected and accepted?......Sisters Hope invites young scholars to visit our elite-school for run-away youngsters. Maybe you will be the next one to be collected and accepted?...

Cohesinopathies of a feather flock together.

Directory of Open Access Journals (Sweden)

Robert V Skibbens

Full Text Available Roberts Syndrome (RBS and Cornelia de Lange Syndrome (CdLS are severe developmental maladies that present with nearly an identical suite of multi-spectrum birth defects. Not surprisingly, RBS and CdLS arise from mutations within a single pathway--here involving cohesion. Sister chromatid tethering reactions that comprise cohesion are required for high fidelity chromosome segregation, but cohesin tethers also regulate gene transcription, promote DNA repair, and impact DNA replication. Currently, RBS is thought to arise from elevated levels of apoptosis, mitotic failure, and limited progenitor cell proliferation, while CdLS is thought to arise, instead, from transcription dysregulation. Here, we review new information that implicates RBS gene mutations in altered transcription profiles. We propose that cohesin-dependent transcription dysregulation may extend to other developmental maladies; the diagnoses of which are complicated through multi-functional proteins that manifest a sliding scale of diverse and severe phenotypes. We further review evidence that cohesinopathies are more common than currently posited.

The ATPases of cohesin interface with regulators to modulate cohesin-mediated DNA tethering

Science.gov (United States)

Çamdere, Gamze; Guacci, Vincent; Stricklin, Jeremiah; Koshland, Douglas

2015-01-01

Cohesin tethers together regions of DNA, thereby mediating higher order chromatin organization that is critical for sister chromatid cohesion, DNA repair and transcriptional regulation. Cohesin contains a heterodimeric ATP-binding Cassette (ABC) ATPase comprised of Smc1 and Smc3 ATPase active sites. These ATPases are required for cohesin to bind DNA. Cohesin’s DNA binding activity is also promoted by the Eco1 acetyltransferase and inhibited by Wpl1. Recently we showed that after cohesin stably binds DNA, a second step is required for DNA tethering. This second step is also controlled by Eco1 acetylation. Here, we use genetic and biochemical analyses to show that this second DNA tethering step is regulated by cohesin ATPase. Furthermore, our results also suggest that Eco1 promotes cohesion by modulating the ATPase cycle of DNA-bound cohesin in a state that is permissive for DNA tethering and refractory to Wpl1 inhibition. DOI: http://dx.doi.org/10.7554/eLife.11315.001 PMID:26583750

Cis-Acting Determinants Affecting Centromere Function, Sister-Chromatid Cohesion and Reciprocal Recombination during Meiosis in Saccharomyces Cerevisiae

OpenAIRE

Sears, D. D.; Hegemann, J. H.; Shero, J. H.; Hieter, P.

1995-01-01

We have employed a system that utilizes homologous pairs of human DNA-derived yeast artificial chromosomes (YACs) as marker chromosomes to assess the specific role (s) of conserved centromere DNA elements (CDEI, CDEII and CDEIII) in meiotic chromosome disjunction fidelity. Thirteen different centromere (CEN) mutations were tested for their effects on meiotic centromere function. YACs containing a wild-type CEN DNA sequence segregate with high fidelity in meiosis I (99% normal segregation) and...

Similar kinetics of chromatid aberrations in X-irradiated xrs 5 and wild-type Chinese hamster ovary cells

International Nuclear Information System (INIS)

MacLeod, R.A.F.; Bryant, P.E.

1990-01-01

We have studied the kinetics of chromatid aberrations in cells of the Chinese hamster ovary (CHO-K1) derived, X-ray sensitive cell line xrs 5 irradiated in the G 2 phase at 37 0 C, as well as during a cell cycle extended by transient hypothermia at 33 0 C. While a given X-ray dose was estimated to produce about 4 times as many chromatid break and twice the frequency of exchanges in xrs 5 cells as in the parent line, there was no difference between the lines in the rates of disappearance of chromatid breaks during G 2 at either temperature; and similar patterns of chromatid exchange kinetics were observed in the two lines. Both the frequencies and distributions of chromatid breaks at different times after irradiation are consistent with the view that the disappearance of these during incubation represents a repair process. These results imply that the G 2 chromosomal radiosensitivity of the xrs 5 mutant resides at the level of initial chromatid damage. (author)

Network cohesion

OpenAIRE

Cavalcanti, Tiago Vanderlei; Giannitsarou, Chrysi; Johnson, CR

2017-01-01

We define a measure of network cohesion and show how it arises naturally in a broad class of dynamic models of endogenous perpetual growth with network externalities. Via a standard growth model, we show why network cohesion is crucial for conditional convergence and explain that as cohesion increases, convergence is faster. We prove properties of network cohesion and define a network aggregator that preserves network cohesion.

Meikin-associated polo-like kinase specifies Bub1 distribution in meiosis I.

Science.gov (United States)

Miyazaki, Seira; Kim, Jihye; Yamagishi, Yuya; Ishiguro, Tadashi; Okada, Yuki; Tanno, Yuji; Sakuno, Takeshi; Watanabe, Yoshinori

2017-06-01

In meiosis I, sister chromatids are captured by microtubules emanating from the same pole (mono-orientation), and centromeric cohesion is protected throughout anaphase. Shugoshin, which is localized to centromeres depending on the phosphorylation of histone H2A by Bub1 kinase, plays a central role in protecting meiotic cohesin Rec8 from separase cleavage. Another key meiotic kinetochore factor, meikin, may regulate cohesion protection, although the underlying molecular mechanisms remain elusive. Here, we show that fission yeast Moa1 (meikin), which associates stably with CENP-C during meiosis I, recruits Plo1 (polo-like kinase) to the kinetochores and phosphorylates Spc7 (KNL1) to accumulate Bub1. Consequently, in contrast to the transient kinetochore localization of mitotic Bub1, meiotic Bub1 persists at kinetochores until anaphase I. The meiotic Bub1 pool ensures robust Sgo1 (shugoshin) localization and cohesion protection at centromeres by cooperating with heterochromatin protein Swi6, which binds and stabilizes Sgo1. Furthermore, molecular genetic analyses show a hierarchical regulation of centromeric cohesion protection by meikin and shugoshin that is important for establishing meiosis-specific chromosome segregation. We provide evidence that the meiosis-specific Bub1 regulation is conserved in mouse. © 2017 Molecular Biology Society of Japan and John Wiley & Sons Australia, Ltd.

In Vivo Cytogenetic Studies on Aspartame

Directory of Open Access Journals (Sweden)

Entissar S. AlSuhaibani

2010-01-01

Full Text Available Aspartame (a-Laspartyl-L-phenylalanine 1-methylester is a dipeptide low-calorie artificial sweetener that is widely used as a nonnutritive sweetener in foods and drinks. The safety of aspartame and its metabolic breakdown products (phenylalanine, aspartic acid and methanol was investigated in vivo using chromosomal aberration (CA test and sister chromatid exchange (SCE test in the bone marrow cells of mice. Swiss Albino male mice were exposed to aspartame (3.5, 35, 350 mg/kg body weight. Bone marrow cells isolated from femora were analyzed for chromosome aberrations and sister chromatid exchanges. Treatment with aspartame induced dose dependently chromosome aberrations at all concentrations while it did not induce sister chromatid exchanges. On the other hand, aspartame did not decrease the mitotic index (MI. However, statistical analysis of the results show that aspartame is not significantly genotoxic at low concentration.

DNA damage in the kidney tissue cells of the fish Rhamdia quelen after trophic contamination with aluminum sulfate

Directory of Open Access Journals (Sweden)

Tatiane Klingelfus

2015-01-01

Full Text Available Abstract Even though aluminum is the third most common element present in the earth's crust, information regarding its toxicity remains scarce. It is known that in certain cases, aluminum is neurotoxic, but its effect in other tissues is unknown. The aim of this work was to analyze the genotoxic potential of aluminum sulfate in kidney tissue of the fish Rhamdia quelen after trophic contamination for 60 days. Sixty four fish were subdivided into the following groups: negative control, 5 mg, 50 mg and 500 mg of aluminum sulfate per kg of fish. Samples of the posterior kidney were taken and prepared to obtain mitotic metaphase, as well as the comet assay. The three types of chromosomal abnormalities (CA found were categorized as chromatid breaks, decondensation of telomeric region, and early separation of sister chromatids. The tests for CA showed that the 5 mg/kg and 50 mg/kg doses of aluminum sulfate had genotoxic potential. Under these treatments, early separation of the sister chromatids was observed more frequently and decondensation of the telomeric region tended to increase in frequency. We suggest that structural changes in the proteins involved in DNA compaction may have led to the decondensation of the telomeric region, making the DNA susceptible to breaks. Moreover, early separation of the sister chromatids may have occurred due to changes in the mobility of chromosomes or proteins that keep the sister chromatids together. The comet assay confirmed the genotoxicity of aluminum sulfate in the kidney tissue of Rhamdia quelen at the three doses of exposure.

The expanding universe of cohesin functions: a new genome stability caretaker involved in human disease and cancer.

Science.gov (United States)

Mannini, Linda; Menga, Stefania; Musio, Antonio

2010-06-01

Cohesin is responsible for sister chromatid cohesion, ensuring the correct chromosome segregation. Beyond this role, cohesin and regulatory cohesin genes seem to play a role in preserving genome stability and gene transcription regulation. DNA damage is thought to be a major culprit for many human diseases, including cancer. Our present knowledge of the molecular basis underlying genome instability is extremely limited. Mutations in cohesin genes cause human diseases such as Cornelia de Lange syndrome and Roberts syndrome/SC phocomelia, and all the cell lines derived from affected patients show genome instability. Cohesin mutations have also been identified in colorectal cancer. Here, we will discuss the human disorders caused by alterations of cohesin function, with emphasis on the emerging role of cohesin as a genome stability caretaker.

Repairability during G1 of the inductor leisure of exchanges in the sister chromatid induced by alkylating agents in DNA substituted and no substituted with BUDR, in cells of the salivary gland of mouse In vivo

International Nuclear Information System (INIS)

Gonzalez B, F.

2004-01-01

In this work you determines the repair of the lesions inductoras of Sister chromatid exchange (ICHs) generated in the cells of the salivary gland of mouse, for the treatment with the N-Methyl-N-Nitrosourea (MNU), the N-Ethyl-N-Nitrosourea (ENU), the Methyl methanesulfonate (MMS) and the Ethyl methanesulfonate (EMS) in early and slow G1 of the first one and the second cellular division, that is to say before and after the cells incorporate 5-bromine-2 -Desoxyuridine (BrdU) in the DNA. Groups witness non treaties were included with mutagen. The cells of the salivary gland repaired the generated lesions partially by the MNU, the MMS and the EMS in the 1st division, and only the lesions induced by the ENU and MMS were repaired partially in the 2nd division. The ENU generates injure that they were not repaired in the 1st division and those taken place by the EMS were little repaired in the 2nd division. The methylating agents generated but ICHs that the ethylating. One observes that the BrdU makes to the molecule of the DNA but susceptible to the damage generated by the alkylating agents that induce the formation of the ICHs. This susceptibility was incremented around 150% for the treatment with the MNU, the ENU and the MMS, on the other hand for the EMS it was 3 times minor. It is proposed that the one electronegative atom of this analog of the timine would to work as a nucleophyllic center with which the electrophyllic compounds react. (Author)

In vivo study on the replicative model validity of sister chromatid exchanges production; Estudio In vivo sobre la validez del modelo replicativo de produccion de intercambios en las cromatidas hermanas

Energy Technology Data Exchange (ETDEWEB)

Cruz V, V L

1997-12-31

The sister chromatid exchanges (SCE) frequency determination has been used as index of damage to DNA, however the biological meaning of this event is still ignored. Different models in order to explain the mechanism of their formation have been proposed and they could be contained in two categories: (a) those that consider that the SCE is produced by means of discrete lesions to the DNA and that they occur in the place of the lesion, and (b) those that propose that the SCE is caused by a group of lesions and that therefore the place in which they occur could not be associated with a lesion in particular. The model of Painter (1980) belongs to this last group. It suggests that the region of the DNA where the clusters are united, is the only place in which the exchange of double chain could happen during the synthesis of the DNA and makes the prediction that since the x rays retard the beginning of the duplication, the pretreatment with ionizing radiation would reduce the frequency of SCE induced by agents capable to block the lengthening of the chain of DNA, that are the most efficient SCE inducers. The objective of the present work was to establish the validity of this replicative model for the SCE formation, based in its prediction. The effect of the unilateral preexposition of mouse to gamma radiation was determined on the SCE induction by Mitomycin C (MMC), in cells of the femoral bone marrow In vivo. This strategy allows to determine the effect of the pretreatment in the same organism, minimizing the variability of the response between individuals. There was not a significant variability between the frequencies of SCE, basal and induced by gamma radiation or MMC in the same organism. The animals that received the gamma radiation pretreatment, showed a reduction of approximately the 30 % in the frequency of SCE, assuming an additive effect of the radiation with the MMC. These results coincide with the prediction of the model of Painter. (Abstract Truncated)

Sisters Hope - the exposed self

DEFF Research Database (Denmark)

Lawaetz, Anna; Hallberg, Gry Worre

Sisters Hope is an art-educational method and a practice-led research tool, rooted in the construction of a fictional parallel universe revolving around the twin sisters Coco and Coca Pebber. Our work is rooted in the ambition to democratize the aesthetic dimension through ‘affective engineering......’ and the establishment of fictional spaces outside the institutional art context. In the Unfolding Academia-context Sisters Hope investigates new forms of research and (re)presentation through the creation of interactive and affective learning-spaces. At Collective Futures Sisters Hope explored questions such as: How...

A comparison of G2 phase radiation-induced chromatid break kinetics using calyculin-PCC with those obtained using colcemid block.

Science.gov (United States)

Bryant, Peter E; Mozdarani, Hossein

2007-09-01

To study the possible influence of cell-cycle delay on cells reaching mitosis during conventional radiation-induced chromatid break experiments using colcemid as a blocking agent, we have compared the chromatid break kinetics following a single dose of gamma rays (0.75 Gy) in metaphase CHO cells using calyculin-induced premature chromosome condensation (PCC), with those using colcemid block. Calyculin-induced PCC causes very rapid condensation of G2 cell chromosomes without the need for a cell to progress to mitosis, hence eliminating any effect of cell-cycle checkpoint on chromatid break frequency. We found that the kinetics of the exponential first-order decrease in chromatid breaks with time after irradiation was similar (not significantly different) between the two methods of chromosome condensation. However, use of the calyculin-PCC technique resulted in a slightly increased rate of disappearance of chromatid breaks and thus higher frequencies of breaks at 1.5 and 2.5 h following irradiation. We also report on the effect of the nucleoside analogue ara A on chromatid break kinetics using the two chromosome condensation techniques. Ara A treatment of cells abrogated the decrease in chromatid breaks with time, both using the calyculin-PCC and colcemid methods. We conclude that cell-cycle delay may be a factor determining the absolute frequency of chromatid breaks at various times following irradiation of cells in G2 phase but that the first-order disappearance of chromatid breaks with time and its abrogation by ara A are not significantly influenced by the G2 checkpoint.

Crystal Structure of the Cohesin Gatekeeper Pds5 and in Complex with Kleisin Scc1

Directory of Open Access Journals (Sweden)

Byung-Gil Lee

2016-03-01

Full Text Available Sister chromatid cohesion is mediated by cohesin, whose Smc1, Smc3, and kleisin (Scc1 subunits form a ring structure that entraps sister DNAs. The ring is opened either by separase, which cleaves Scc1 during anaphase, or by a releasing activity involving Wapl, Scc3, and Pds5, which bind to Scc1 and open its interface with Smc3. We present crystal structures of Pds5 from the yeast L. thermotolerans in the presence and absence of the conserved Scc1 region that interacts with Pds5. Scc1 binds along the spine of the Pds5 HEAT repeat fold and is wedged between the spine and C-terminal hook of Pds5. We have isolated mutants that confirm the observed binding mode of Scc1 and verified their effect on cohesin by immunoprecipitation and calibrated ChIP-seq. The Pds5 structure also reveals architectural similarities to Scc3, the other large HEAT repeat protein of cohesin and, most likely, Scc2.

Detection of Ultrafine Anaphase Bridges

DEFF Research Database (Denmark)

Bizard, Anna H; Nielsen, Christian F; Hickson, Ian D

2018-01-01

Ultrafine anaphase bridges (UFBs) are thin DNA threads linking the separating sister chromatids in the anaphase of mitosis. UFBs are thought to form when topological DNA entanglements between two chromatids are not resolved prior to anaphase onset. In contrast to other markers of defective...

Network cohesion

OpenAIRE

Cavalcanti, Tiago V. V.; Giannitsarou, Chryssi; Johnson, Charles R.

2016-01-01

This is the final version of the article. It first appeared from Springer via http://dx.doi.org/10.1007/s00199-016-0992-1 We define a measure of network cohesion and show how it arises naturally in a broad class of dynamic models of endogenous perpetual growth with network externalities. Via a standard growth model, we show why network cohesion is crucial for conditional convergence and explain that as cohesion increases, convergence is faster. We prove properties of network cohesion and d...

Perturbation of Incenp function impedes anaphase chromatid movements and chromosomal passenger protein flux at centromeres.

Science.gov (United States)

Ahonen, Leena J; Kukkonen, Anu M; Pouwels, Jeroen; Bolton, Margaret A; Jingle, Christopher D; Stukenberg, P Todd; Kallio, Marko J

2009-02-01

Incenp is an essential mitotic protein that, together with Aurora B, Survivin, and Borealin, forms the core of the chromosomal passenger protein complex (CPC). The CPC regulates various mitotic processes and functions to maintain genomic stability. The proper subcellular localization of the CPC and its full catalytic activity require the presence of each core subunit in the complex. We have investigated the mitotic tasks of the CPC using a function blocking antibody against Incenp microinjected into cells at different mitotic phases. This method allowed temporal analysis of CPC functions without perturbation of complex assembly or activity prior to injection. We have also studied the dynamic properties of Incenp and Aurora B using fusion protein photobleaching. We found that in early mitotic cells, Incenp and Aurora B exhibit dynamic turnover at centromeres, which is prevented by the anti-Incenp antibody. In these cells, the loss of centromeric CPC turnover is accompanied by forced mitotic exit without the execution of cytokinesis. Introduction of anti-Incenp antibody into early anaphase cells causes abnormalities in sister chromatid separation through defects in anaphase spindle functions. In summary, our data uncovers new mitotic roles for the CPC in anaphase and proposes that CPC turnover at centromeres modulates spindle assembly checkpoint signaling.

Investigations into the molecular mechanism of chromatid breakage in the G2-phase of mammalian cells

International Nuclear Information System (INIS)

Bryant, P.E.; Armstrong, G.N.; Gray, L.; Frankenberg, D.; Mozdarani, H.

2003-01-01

Chromatid breakage following irradiation of cells in the G2-phase of the cell cycle results from the induction of DNA double-strand breaks (dsb). The conversion of dsb into chromatid breaks (cb) has a genetic basis, seemingly different from that of dsb rejoining. The variation in extent of this conversion is exemplified by the stiking variation in frequency of cb in irradiated cycling T-lymphocytes between different normal individuals. Elevated cb frequency in lymphocytes of around 40% of breast cancer patients and their first-degree relatives suggests the presence of mutations in low penetrance cancer predisposing genes that also affect conversion of dsb to cb. Investigation of the mechanism of chromatid radiosensitivity using genetically engineered rodent cell lines containing unique dsb break sites indicate that a single isolated dsb is sufficient to cause a cb. The single-event nature of chromatid breakage is confirmed by the fact that cb are induced as a linear function of radiation dose. Moreover, we have recently shown that ultrasoft carbon-K X-rays also induce chromatid breakage. In this case the energy of the secondary electrons produced by carbon-K X-rays is too low to span more than one DNA double helix, thus further supporting our conclusion that a single dsb is responsible for the formation of a cb. Chromatid breakage is thought to involve a rearrangement between DNA strands at the crossover points of chromatin loop(s) triggered by the presence of a dsb within the loop structure. The occasional observation of 'looped-out' sections of chromatin at cb sites supports this hypothesis. The occurrence of 'colour-switches' between FPG stained chromatids at a proportion of break sites (e.g. about 16% in CHO cells) shows that a significant proportion of cb definitely result from chromatin rearrangements. Measurements of altered colour-switch ratio (csr) in mutant rodent and human cells (irs1 and AT cells respectively) also indicate a genetic basis for the

Differential features of sister-chromatid exchange responses to ultraviolet radiation and caffeine in xeroderma pigmentosum lymphoblastoid cell lines

International Nuclear Information System (INIS)

Tohda, H.; Oikawa, A.

1983-01-01

Sister-chromatic exchange (SCE) induced by ultraviolet (UV) irradiation and viability after UV irradiation were studied in lymphoblastoid cell lines derived from 7 patients with xeroderma pigmentosum (XP) and 6 normal donors. UV irradiation caused significant increases of SCEs in both XP and normal cells. In 3 XP cell lines, which were deficient in unscheduled DNA synthesis (UDS) and sensitive to the killing effect of UV, very high SCE frequencies were observed after UV irradiation. Cells from a patient with the De Sanctis-Cacchione syndrome were the most sensitive to UV in terms of both SCE induction and cell killing. In 2 of 4 UDS-proficient XP cell lines tested, the incidences of UV-induced SCEs were similar to those in normal cell lines, but in 2 other UDS-proficient lines from 2 XP patients with skin cancer, the frequencies of UV-induced SCEs were significantly higher than in normal cells. (orig./AJ)

Proteomic analysis of human metaphase chromosomes reveals Topoisomerase II alpha as an Aurora B substrate

DEFF Research Database (Denmark)

Morrison, Ciaran; Henzing, Alexander J; Jensen, Ole Nørregaard

2002-01-01

B in the presence of radioactive ATP. Immunoblot analysis confirmed the HeLa scaffold fraction to be enriched for known chromosomal proteins including CENP-A, CENP-B, CENP-C, ScII and INCENP. Mass spectrometry of bands excised from one-dimensional polyacrylamide gels further defined the protein......The essential Aurora B kinase is a chromosomal passenger protein that is required for mitotic chromosome alignment and segregation. Aurora B function is dependent on the chromosome passenger, INCENP. INCENP, in turn, requires sister chromatid cohesion for its appropriate behaviour. Relatively few...... composition of the extracted chromosome fraction. Cloning, fluorescent tagging and expression in HeLa cells of the putative GTP-binding protein NGB/CRFG demonstrated it to be a novel mitotic chromosome protein, with a perichromosomal localisation. Identi fication of the protein bands corresponding to those...

[Inverted meiosis and its place in the evolution of sexual reproduction pathways].

Science.gov (United States)

Bogdanov, Yu F

2016-05-01

Inverted meiosis is observed in plants (Cyperaceae and Juncaceae) and insects (Coccoidea, Aphididae) with holocentric chromosomes, the centromeres of which occupy from 70 to 90% of the metaphase chromosome length. In the first meiotic division (meiosis I), chiasmata are formed and rodlike bivalents orient equationally, and in anaphase I, sister chromatids segregate to the poles; the diploid chromosome number is maintained. Non-sister chromatids of homologous chromosomes remain in contact during interkinesis and prophase II and segregate in anaphase II, forming haploid chromosome sets. The segregation of sister chromatids in meiosis I was demonstrated by example of three plant species that were heterozygous for chromosomal rearrangements. In these species, sister chromatids, marked with rearrangement, segregated in anaphase I. Using fluorescent antibodies, it was demonstrated that meiotic recombination enzymes Spo11 and Rad5l, typical of canonical meiosis, functioned at the meiotic prophase I of pollen mother cells of Luzula elegance and Rhynchospora pubera. Moreover, antibodies to synaptonemal complexes proteins ASY1 and ZYP1 were visualized as filamentous structures, pointing to probable formation of synaptonemal complexes. In L. elegance, chiasmata are formed by means of chromatin threads containing satellite DNA. According to the hypothesis of the author of this review, equational division of sister chromatids at meiosis I in the organisms with inverted meiosis can be explained by the absence of specific meiotic proteins (shugoshins). These proteins are able to protect cohesins of holocentric centromeres from hydrolysis by separases at meiosis I, as occurs in the organisms with monocentric chromosomes and canonical meiosis. The basic type of inverted meiosis was described in Coccoidea and Aphididae males. In their females, the variants of parthenogenesis were also observed. Until now, the methods of molecular cytogenetics were not applied for the analysis of

The hsSsu72 phosphatase is a cohesin-binding protein that regulates the resolution of sister chromatid arm cohesion

OpenAIRE

Kim, Hyun-Soo; Baek, Kwan-Hyuck; Ha, Geun-Hyoung; Lee, Jae-Chul; Kim, Yu-Na; Lee, Janet; Park, Hye-Young; Lee, Noo Ri; Lee, Ho; Cho, Yunje; Lee, Chang-Woo

2010-01-01

An interplay of phosphorylation, dephosphorylation and protecting factors controls proteolysis-independent cohesin dissociation from chromosomes. The identification of a new phosphatase protecting arm cohesin now adds further complexity to this regulation.

Post-irradiation treatment of human lymphocytes with spermidine reduced frequency of chromatid breaks

International Nuclear Information System (INIS)

Bocian, E.; Rosiek, O.; Ziemba-Zoltowska, B.

1978-01-01

Human lymphocyte cultures were X-irradiated with a single dose of 100 or 200 rad 46 h after phytohemagglutinin stimulation. In dose-fractionation experiments, 2h later the second dose was applied. All the cultures were harvested at 54 h after their initiation. In lymphocytes irradiated with a single dose of 200 rad, 2h post-irradiation contact with 10 -5 M exogeneous spermidine resulted in reduction of chromatid breaks by 34 %. Introduction of spermidine into culture medium for fractionation interval between the 2 doses of 100 rad reduced the frequency of chromatid breaks by 42 %. (author)

Chromatid interchanges at intrachromosomal telomeric DNA sequences

International Nuclear Information System (INIS)

Fernandez, J.L.; Vazquez-Gundin, F.; Bilbao, A.; Gosalvez, J.; Goyanes, V.

1997-01-01

Chinese hamster Don cells were exposed to X-rays, mitomycin C and teniposide (VM-26) to induce chromatid exchanges (quadriradials and triradials). After fluorescence in situ hybridization (FISH) of telomere sequences it was found that interstitial telomere-like DNA sequence arrays presented around five times more breakage-rearrangements than the genome overall. This high recombinogenic capacity was independent of the clastogen, suggesting that this susceptibility is not related to the initial mechanisms of DNA damage. (author)

Abnormal centromere-chromatid apposition (ACCA) and Peters' anomaly.

Science.gov (United States)

Wertelecki, W; Dev, V G; Superneau, D W

1985-08-01

Abnormal centromere-chromatid apposition (ACCA) was noted in a patient with Peters' anomaly. Previous reports of ACCA emphasized its association with tetraphocomelia and other congenital malformations (Roberts, SC Phocomelia, Pseudothalidomide Syndromes). This report expands the array of congenital malformations associated with ACCA and emphasizes the diagnostic importance of ocular defects for the ascertainment of additional cases of ACCA and its possible relationship with abnormal cell division.

Role of oxidative stress and intracellular calcium in nickel carbonate hydroxide-induced sister-chromatid exchange, and alterations in replication index and mitotic index in cultured human peripheral blood lymphocytes

Energy Technology Data Exchange (ETDEWEB)

M' Bemba-Meka, Prosper [Universite de Montreal, Human Toxicology Research Group (TOXHUM), Department of Environmental and Occupational Health, Main Station, P.O. Box 6128, Montreal, QC (Canada); University of Louisville, Department of Pharmacology and Toxicology, Center for Genetics and Molecular Medicine, Louisville, KY (United States); Lemieux, Nicole [Universite de Montreal, Department of Pathology and Cellular Biology, Faculty of Medicine, Main Station, P.O. Box 6128, Montreal, QC (Canada); Chakrabarti, Saroj K. [Universite de Montreal, Human Toxicology Research Group (TOXHUM), Department of Environmental and Occupational Health, Main Station, P.O. Box 6128, Montreal, QC (Canada)

2007-02-15

Human peripheral lymphocytes from whole blood cultures were exposed to either soluble form of nickel carbonate hydroxide (NiCH) (0-60 {mu}M), or of nickel subsulfide (Ni{sub 3}S{sub 2}) (0-120 {mu}M), or of nickel oxide (NiO) (0-120 {mu}M), or nickel sulfate (NiSO{sub 4}) (0-120 {mu}M) for a short duration of 2 h. The treatments occurred 46 h after the beginning of the cultures. The cultures were harvested after a total incubation of 72 h, and sister-chromatid exchange (SCE), replication index (RI), and mitotic index (MI) were measured for each nickel compound. The soluble form of NiCH at 30 {mu}M but those of Ni{sub 3}S{sub 2} and NiO at 120 {mu}M produced significant increase in the SCE per cell compared to the control value, whereas NiSO{sub 4} failed to produce any such significant increase. Except NiSO{sub 4}, the soluble forms of NiCH, Ni{sub 3}S{sub 2}, and NiO produced significant cell-cycle delay (as measured by the inhibition of RI) as well as significant inhibition of the MI at respective similar concentrations as mentioned above. Pretreatment of human blood lymphocytes with catalase (H{sub 2}O{sub 2} scavenger), or superoxide dismutase (superoxide anion scavenger), or dimethylthiourea (hydroxyl radical scavenger), or deferoxamine (iron chelator), or N-acetylcysteine (general antioxidant) inhibited NiCH-induced SCE, and changes in RI and MI. This suggests the participation of oxidative stress involving H{sub 2}O{sub 2}, the superoxide anion radical, the hydroxyl radical, and iron in the NiCH-induced genotoxic responses. Cotreatment of NiCH with either verapamil (inhibitor of intracellular calcium ion ([Ca{sup 2+}]{sub i}) movement through plasma membranes), or dantrolene (inhibitor of [Ca{sup 2+}]{sub i} release from sarcoplasmic reticulum), or BAPTA (Ca{sup 2+} chelator) also inhibited the NiCH-induced responses. These results suggest that [Ca{sup 2+}]{sub i} is also implicated in the genotoxicity of NiCH. Overall these data indicate that various types

Teenage pregnancy: the impact of maternal adolescent childbearing and older sister's teenage pregnancy on a younger sister.

Science.gov (United States)

Wall-Wieler, Elizabeth; Roos, Leslie L; Nickel, Nathan C

2016-05-25

Risk factors for teenage pregnancy are linked to many factors, including a family history of teenage pregnancy. This research examines whether a mother's teenage childbearing or an older sister's teenage pregnancy more strongly predicts teenage pregnancy. This study used linkable administrative databases housed at the Manitoba Centre for Health Policy (MCHP). The original cohort consisted of 17,115 women born in Manitoba between April 1, 1979 and March 31, 1994, who stayed in the province until at least their 20(th) birthday, had at least one older sister, and had no missing values on key variables. Propensity score matching (1:2) was used to create balanced cohorts for two conditional logistic regression models; one examining the impact of an older sister's teenage pregnancy and the other analyzing the effect of the mother's teenage childbearing. The adjusted odds of becoming pregnant between ages 14 and 19 for teens with at least one older sister having a teenage pregnancy were 3.38 (99 % CI 2.77-4.13) times higher than for women whose older sister(s) did not have a teenage pregnancy. Teenage daughters of mothers who had their first child before age 20 had 1.57 (99 % CI 1.30-1.89) times higher odds of pregnancy than those whose mothers had their first child after age 19. Educational achievement was adjusted for in a sub-population examining the odds of pregnancy between ages 16 and 19. After this adjustment, the odds of teenage pregnancy for teens with at least one older sister who had a teenage pregnancy were reduced to 2.48 (99 % CI 2.01-3.06) and the odds of pregnancy for teen daughters of teenage mothers were reduced to 1.39 (99 % CI 1.15-1.68). Although both were significant, the relationship between an older sister's teenage pregnancy and a younger sister's teenage pregnancy is much stronger than that between a mother's teenage childbearing and a younger daughter's teenage pregnancy. This study contributes to understanding of the broader topic "who is

Interchromosomal distribution of gamma ray-induced chromatid aberrations in Chinese hamster ovary cells

International Nuclear Information System (INIS)

Martinez-Lopez, Wilner; Porro, Valentina; Folle, Gustavo A.; Mendez-Acuna, Leticia; Obe, Guenter; Savage, John R.K.

2000-01-01

Inter chromosomal distributions of breakpoints from chromatid-type aberrations induced by gamma rays in Chinese hamster ovary cells were analyzed. In most chromosomes the distribution was as expected from chromosome lengths for simple breaks or the respective relative corrected length in case of exchanges. There were deviations from expectation in a few chromosomes for chromatid breaks, interchanges, intra-arm intra changes and inter-arm intra changes. Especially interesting are the results concerning chromosomes 2 and 8, which were more often involved in exchanges than expected. An 'exchange phenotype' for these chromosomes is proposed and possible explanations for the nonrandom distribution of chromosome breakpoints are presented. (author)

Consumerism and the Sister Carrie's American Dream%Consumerism and the Sister Carrie''s American Dream

Institute of Scientific and Technical Information of China (English)

卢亚丽

2017-01-01

From the aspect of consumerism to this text analyze Sister Carrie's"American dream"destruction. The author wholly and deeply analyzes the embodiment of consumerism in Dreiser's Sister Carrie and Dreiser's outlook and values under the effect of consumerism. To prove that the reason for destruction of Carrie's American dream is consumerism.

Mps1 kinase-dependent Sgo2 centromere localisation mediates cohesin protection in mouse oocyte meiosis I

NARCIS (Netherlands)

Yakoubi, W. El; Buffin, E.; Cladiere, D.; Gryaznova, Y.; Berenguer, I.; Touati, S.A.; Gomez, R.; Suja, J.A.; Deursen, J.M.A. van; Wassmann, K.

2017-01-01

A key feature of meiosis is the step-wise removal of cohesin, the protein complex holding sister chromatids together, first from arms in meiosis I and then from the centromere region in meiosis II. Centromeric cohesin is protected by Sgo2 from Separase-mediated cleavage, in order to maintain sister

Somatomedin C deficiency in Asian sisters.

OpenAIRE

McGraw, M E; Price, D A; Hill, D J

1986-01-01

Two sisters of Asian origin showed typical clinical and biochemical features of primary somatomedin C (SM-C) deficiency (Laron dwarfism). Abnormalities of SM-C binding proteins were observed, one sister lacking the high molecular weight (150 Kd) protein.

Analysis of chromosomal aberrations, sister-chromatid exchanges and micronuclei in peripheral lymphocytes of pharmacists before and after working with cytostatic drugs.

Science.gov (United States)

Roth, S; Norppa, H; Järventaus, H; Kyyrönen, P; Ahonen, M; Lehtomäki, J; Sainio, H; Sorsa, M

1994-12-01

The frequencies of chromosome aberrations, SCEs and micronuclei (cytokinesis-block method) in blood lymphocytes were compared among six nonsmoking female pharmacists before and after 1 year of working with cytostatic drugs. All possible precautions were taken to avoid exposure to cytostatics, including proper protective clothing and a monitored, negative-pressured working environment with vertical laminar flow cabinet. As referents, an age-matched group of six nonsmoking female hospital workers not dealing with cytostatics was simultaneously sampled twice with the same time interval. The pharmacists showed a marginally higher mean frequency of SCEs/cell (6.3; P = 0.049) after the working period than 1 year earlier (5.8). On the other hand, the referents, with no obvious exposure, had a higher mean number of cells with chromatid-type aberrations, gaps excluded, in the second sampling (2.0%; P = 0.048) than in the first one (0.5%). In addition, a slight (P = 0.055) trend towards a higher frequency of micronucleated binucleate cells was observed in the second sampling for both the exposed and control subjects. As such findings suggest technical variation in the cytogenetic parameters, the small difference observed in SCEs for the pharmacists between the two samplings was probably not related to the cytostatics exposure. No statistically significant differences were observed for any of the cytogenetic parameters in comparisons between the pharmacists and the referents. The findings suggest that caution should be exercised in comparing results obtained from two different samplings in prospective cytogenetic studies.

Eruptive history of South Sister, Oregon Cascades

Science.gov (United States)

Fierstein, J.; Hildreth, W.; Calvert, A.T.

2011-01-01

South Sister is southernmost and highest of the Three Sisters, three geologically dissimilar stratovolcanoes that together form a spectacular 20km reach along the Cascade crest in Oregon. North Sister is a monotonously mafic edifice as old as middle Pleistocene, Middle Sister a basalt-andesite-dacite cone built between 48 and 14ka, and South Sister is a basalt-free edifice that alternated rhyolitic and intermediate modes from 50ka to 2ka (largely contemporaneous with Middle Sister). Detailed mapping, 330 chemical analyses, and 42 radioisotopic ages show that the oldest exposed South Sister lavas were initially rhyolitic ~50ka. By ~37ka, rhyolitic lava flows and domes (72-74% SiO2) began alternating with radially emplaced dacite (63-68% SiO2) and andesite (59-63% SiO2) lava flows. Construction of a broad cone of silicic andesite-dacite (61-64% SiO2) culminated ~30ka in a dominantly explosive sequence that began with crater-forming andesitic eruptions that left fragmental deposits at least 200m thick. This was followed at ~27ka by growth of a steeply dipping summit cone of agglutinate-dominated andesite (56-60.5% SiO2) and formation of a summit crater ~800m wide. This crater was soon filled and overtopped by a thick dacite lava flow and then by >150m of dacitic pyroclastic ejecta. Small-volume dacite lavas (63-67% SiO2) locally cap the pyroclastic pile. A final sheet of mafic agglutinate (54-56% SiO2) - the most mafic product of South Sister - erupted from and drapes the small (300-m-wide) present-day summit crater, ending a summit-building sequence that lasted until ~22ka. A 20kyr-long-hiatus was broken by rhyolite eruptions that produced (1) the Rock Mesa coulee, tephra, and satellite domelets (73.5% SiO2) and (2) the Devils Chain of ~20 domes and short coulees (72.3-72.8% SiO2) from N-S vent alignments on South Sister's flanks. The compositional reversal from mafic summit agglutinate to recent rhyolites epitomizes the frequently changing compositional modes of the

The Structure of Group Cohesion.

Science.gov (United States)

Cota, Albert A.; And Others

1995-01-01

Reviews the literature on unidimensional and multidimensional models of cohesion and describes cohesion as a multidimensional construct with primary and secondary dimensions. Found that primary dimensions described the cohesiveness of all or most types of groups, whereas secondary dimensions only described the cohesiveness of specific types of…

Induction and disappearance of G2 chromatid breaks in lymphocytes after low doses of low LET γ - rays and high LET fast neutrons

International Nuclear Information System (INIS)

Vral, Anne; Thierens, Hubert; Baeyens, Ans; De Ridder, Leo

2001-01-01

In view of the potential importance of the G2 assay for detecting chromosomal radiosensitivity and possible predisposition to cancer the need to elucidate the mechanism underlying the formation of chromatid breaks, observed with the G2 assay after low dose irradiation, has been recognised. In this study we irradiated blood samples of 4 healthy donors with low LET γ-rays and high LET neutrons, which initially produce the same number of dsb but of a different quality. By means of the G2 assay, we determined the number of chromatid breaks induced by γ-rays and neutrons and compared the kinetics of chromatid break rejoining for radiations of different quality. In a first set of experiments a dose-response curve for the formation of chromatid breaks was carried out for γ-rays and neutrons with doses ranging between 0.1 and 0.5 Gy. In a second set of experiments the kinetics of chromatid break formation and disappearance was investigated after a dose of 0.5 Gy using post-irradiation times ranging between 0.5 h and 3.5 h. For the highest dose of 0.5 Gy the number of isochromatid breaks were also scored. No significant differences in the number of chromatid breaks were observed between low LET γ-rays and high LET neutrons for the 4 donors at any of the doses given. The dose response curves for the formation of chromatid breaks are linear for both radiation qualities and RBE values equal to one were obtained. Scoring of isochromatid breaks at the highest dose of 0.5 Gy revealed that high LET neutrons are however more effective at inducing isochromatid breaks (RBE of 6.2). The rejoining experiments further showed that the kinetics of disappearance of chromatid breaks following irradiation with low LET γ-rays or high-LET neutrons are not significantly different. T 1/2 0.92 h for γ-rays and t 1/2 = 0.84 h for neutrons were obtained. In conclusion, our results show that at low doses of radiation the induction as well as the disappearance of G2 chromatid breaks is LET

Male meiosis in Crustacea: synapsis, recombination, epigenetics and fertility in Daphnia magna.

Science.gov (United States)

Gómez, Rocío; Van Damme, Kay; Gosálvez, Jaime; Morán, Eugenio Sánchez; Colbourne, John K

2016-09-01

We present the first detailed cytological study of male meiosis in Daphnia (Crustacea: Branchiopoda: Cladocera)-an aquatic microcrustacean with a cyclical parthenogenetic life cycle. Using immunostaining of the testes in Daphnia magna for baseline knowledge, we characterized the different stages of meiotic division and spermiogenesis in relation to the distribution of proteins involved in synapsis, early recombination events and sister chromatid cohesion. We also studied post-translational histone modifications in male spermatocytes, in relation to the dynamic chromatin progression of meiosis. Finally, we applied a DNA fragmentation test to measure sperm quality of D. magna, with respect to levels of inbreeding. As a proxy for fertility, this technique may be used to assess the reproductive health of a sentinel species of aquatic ecosystems. Daphnia proves to be a model species for comparative studies of meiosis that is poised to improve our understanding of the cytological basis of sexual and asexual reproduction.

Relationship of the demethylation of the DNA with the induction of the sister chromatid exchanges (SCE) In vivo; Relacion de la desmetilacion del ADN con la induccion de intercambios en las cromatidas hermanas (ICH) In vivo

Energy Technology Data Exchange (ETDEWEB)

Toribio E, E

2005-07-01

The methylation of the DNA is an epigenetic modification that has an important paper in the regulation of the functionality of the genome of the organisms. It can be altered by demethylation processes, either natural or experimentally induced. The 5-azacytidine (Aza) is a compound that causes the demethylation of the DNA (dm-DNA), inducing with it, expression genic and increase in the frequency of the Sister Chromatid Exchange (SCE). The SCE is a genotoxicity indicator, caused by diverse mutagens and carcinogen. Since the biological meaning and the formation mechanism of this phenomenon has not been totally illustrious, the exploration of the relation between the dm-DNA and the induction of SCE, it could offer new knowledge to explain those queries. The purpose of this work was to study in cells of the mouse bone marrow In vivo, the effect of the Aza on the induction of SCE, based on two aspects: 1) dose answer and 2) the effectiveness of multiple exhibition. To six groups of three to five animals, they are administered Aza to dose of 5, 10, 15 or 20 mg/Kg of weight; in sharp or multiple form, previously to the bromodeoxyuridine supply and 24 h was sacrificed after this; 2 h after an injection with colchicine. Preparations of those metaphases were made, those which were dyed by means of a technique of fluorescence more Giemsa. It was observed that to sharp low dose, the Aza produced an increment in the frequency of SCE that although small it was proportional and statistically significant. To sharp and multiple high doses, the Aza doesn't cause additional increments of SCE, but if toxicity at cellular level and of individuals. It is concluded that a relationship exists between the dm-DNA and the induction of SCE. It is suggested that the total demethylation of the DNA causes 2 SCE/Cell in cells of the mouse bone marrow, or that the cytotoxicity prevents to evidence a bigger induction. (Author)

Relationship of the demethylation of the DNA with the induction of the sister chromatid exchanges (SCE) In vivo; Relacion de la desmetilacion del ADN con la induccion de intercambios en las cromatidas hermanas (ICH) In vivo

Energy Technology Data Exchange (ETDEWEB)

Toribio E, E

2005-07-01

The methylation of the DNA is an epigenetic modification that has an important paper in the regulation of the functionality of the genome of the organisms. It can be altered by demethylation processes, either natural or experimentally induced. The 5-azacytidine (Aza) is a compound that causes the demethylation of the DNA (dm-DNA), inducing with it, expression genic and increase in the frequency of the Sister Chromatid Exchange (SCE). The SCE is a genotoxicity indicator, caused by diverse mutagens and carcinogen. Since the biological meaning and the formation mechanism of this phenomenon has not been totally illustrious, the exploration of the relation between the dm-DNA and the induction of SCE, it could offer new knowledge to explain those queries. The purpose of this work was to study in cells of the mouse bone marrow In vivo, the effect of the Aza on the induction of SCE, based on two aspects: 1) dose answer and 2) the effectiveness of multiple exhibition. To six groups of three to five animals, they are administered Aza to dose of 5, 10, 15 or 20 mg/Kg of weight; in sharp or multiple form, previously to the bromodeoxyuridine supply and 24 h was sacrificed after this; 2 h after an injection with colchicine. Preparations of those metaphases were made, those which were dyed by means of a technique of fluorescence more Giemsa. It was observed that to sharp low dose, the Aza produced an increment in the frequency of SCE that although small it was proportional and statistically significant. To sharp and multiple high doses, the Aza doesn't cause additional increments of SCE, but if toxicity at cellular level and of individuals. It is concluded that a relationship exists between the dm-DNA and the induction of SCE. It is suggested that the total demethylation of the DNA causes 2 SCE/Cell in cells of the mouse bone marrow, or that the cytotoxicity prevents to evidence a bigger induction. (Author)

The Monopolin Complex Crosslinks Kinetochore Components to Regulate Chromosome-Microtubule Attachments

Energy Technology Data Exchange (ETDEWEB)

Corbett, Kevin D.; Yip, Calvin K.; Ee, Ly-Sha; Walz, Thomas; Amon, Angelika; Harrison, Stephen C. (Harvard-Med); (MIT)

2010-09-27

The monopolin complex regulates different types of kinetochore-microtubule attachments in fungi, ensuring sister chromatid co-orientation in Saccharomyces cerevisiae meiosis I and inhibiting merotelic attachment in Schizosaccharomyces pombe mitosis. In addition, the monopolin complex maintains the integrity and silencing of ribosomal DNA (rDNA) repeats in the nucleolus. We show here that the S. cerevisiae Csm1/Lrs4 monopolin subcomplex has a distinctive V-shaped structure, with two pairs of protein-protein interaction domains positioned {approx}10 nm apart. Csm1 presents a conserved hydrophobic surface patch that binds two kinetochore proteins: Dsn1, a subunit of the outer-kinetochore MIND/Mis12 complex, and Mif2/CENP-C. Csm1 point-mutations that disrupt kinetochore-subunit binding also disrupt sister chromatid co-orientation in S. cerevisiae meiosis I. We further show that the same Csm1 point-mutations affect rDNA silencing, probably by disrupting binding to the rDNA-associated protein Tof2. We propose that Csm1/Lrs4 functions as a molecular clamp, crosslinking kinetochore components to enforce sister chromatid co-orientation in S. cerevisiae meiosis I and to suppress merotelic attachment in S. pombe mitosis, and crosslinking rDNA repeats to aid rDNA silencing.

Forms of cohesion in confinement institutions

Directory of Open Access Journals (Sweden)

Ekaterina D. Slobodenyuk

2015-12-01

Full Text Available Objective to identify the diversity of cohesion forms in confinement institutions. Methods qualitative analyses based on indepth semistructured interviews. Results the study included adaptation of Western methodologies of the cohesion phenomenon analysis to the Russian reality and operationalization of the moral bases of group cohesion. This served as the bases for designing a guide for indepth semistructured interviews 10 interviews were conducted with people recently released from general and strict regime colonies. Content analysis of the interviews revealed a number of structural sections that demonstrate the diversity of cohesion forms alongside with one that is most meaningful to the prisoners and therefore the most well perceived and articulated by respondents. Analysis of the latter allowed to identify a set of groups showing different degree and nature of cohesion. By the degree of cohesion one can identify the poorly cohesive groups quotloutsquot moderately cohesive quotredsquot quotthievesquot and highly cohesive quotfightersquot. By the nature of cohesion in the prisonersrsquo community there are both groups united on the basis of social morality quotredsquot quotthievesquot and groups demonstrating a high degree of cohesion based on the social justice morality quotfightersquot. A detailed analysis of the latter group also showed that the cohesion can have both traits of morality social justice and features of social order moral. Scientific novelty using the sociopsychological theory of the moral motives in determining the bases of cohesion. Practical significance the research results can be applied for the development of sociopsychological techniques for the penal system reform.

Non-random intrachromosomal distribution of radiation-induced chromatid aberrations in Vicia faba. [Aberration clustering

Energy Technology Data Exchange (ETDEWEB)

Schubert, I; Rieger, R [Akademie der Wissenschaften der DDR, Gatersleben. Zentralinst. fuer Genetik und Kulturpflanzenforschung

1976-04-01

A reconstructed karyotype of Vicia faba, with all chromosomes individually distinguishable, was treated with X-rays, fast neutrons, (/sup 3/H) uridine (/sup 3/HU). The distribution within metaphase chromosomes of induced chromatid aberrations was non-random for all agents used. Aberration clustering, in part agent specific, occurred in chromosome segments containing heterochromatin as defined by the presence of G bands. The pattern of aberration clustering found after treatment with /sup 3/HU did not allow the recognition of chromosome regions active in transcription during treatment. Furthermore, it was impossible to obtain unambiguous indications of the presence of AT- and GC-base clusters from the patterns of /sup 3/HT- and /sup 3/HC-induced chromatid aberrations, respectively. Possible reasons underlying these observations are discussed.

Two Nepali Sisters

DEFF Research Database (Denmark)

Hansen, Annette Skovsted

Diaspora is an expansion of a national or family network that can be activated for the benefit of the family and home nation in multiple ways. The argument is based on two life stories. Two Nepali sisters attended Association of Overseas Technical Scholarships (AOTS) training courses in Japan...... at different times during the 1980s. The training was partly funded by official development assistance provided through the Japanese Ministry of International Trade and Industry (MITI). They used their training very differently, but between the two of them extended a family network from Japan and India...... still pursuing a career in a Japanese company. Their children have or are studying in Japan, India, and the USA. The Nepal-based sister is a key stakeholder in the regional cooperation in South Asia. By engaging network theories of weak ties and scaled networks, the life stories become templates...

Developing skills in clinical leadership for ward sisters.

Science.gov (United States)

Fenton, Katherine; Phillips, Natasha

The Francis report has called for a strengthening of the ward sister's role. It recommends that sisters should operate in a supervisory capacity and should not be office bound. Effective ward leadership has been recognised as being vital to high-quality patient care and experience, resource management and interprofessional working. However, there is evidence that ward sisters are ill equipped to lead effectively and lack confidence in their ability to do so. University College London Hospitals Foundation Trust has recognised that the job has become almost impossible in increasingly large and complex organisations. Ward sisters spend less than 40% of their time on clinical leadership and the trust is undertaking a number of initiatives to support them in this role.

A Study on the Effect of Cohesive Laws on Finite Element Analysis of Crack Propagation Using Cohesive Elements

Energy Technology Data Exchange (ETDEWEB)

Seo, Hyeongseok; Baek, Hyungchan; Kim, Hyungyu [Seoul Nat' l Univ. of Sci. and Tech., Seoul (Korea, Republic of)

2014-04-15

In this paper, the effect of cohesive laws on the finite element analysis of crack propagation using cohesive elements is investigated through three-point bending and double cantilever beam problems. The cohesive elements are implemented into ABAQUS/Standard user subroutines(UEL), and the shape of cohesive law is varied by changing parameters in polynomial functions of cohesive traction-separation relations. In particular, crack propagation behaviors are studied by comparing load-displacement curves of the analysis models which have different shapes of cohesive laws with the same values of fracture energy and cohesive strength. Furthermore, the influence of the element size on crack propagation is discussed in this study.

Consumerism and the Sister Carrie's American Dream

Institute of Scientific and Technical Information of China (English)

卢亚丽

2017-01-01

From the aspect of consumerism to this text analyze Sister Carrie's"American dream"destruction. The author wholly and deeply analyzes the embodiment of consumerism in Dreiser's Sister Carrie and Dreiser's outlook and values under the effect of consumerism. To prove that the reason for destruction of Carrie's American dream is consumerism.

Mps1 kinase-dependent Sgo2 centromere localisation mediates cohesin protection in mouse oocyte meiosis I.

Science.gov (United States)

El Yakoubi, Warif; Buffin, Eulalie; Cladière, Damien; Gryaznova, Yulia; Berenguer, Inés; Touati, Sandra A; Gómez, Rocío; Suja, José A; van Deursen, Jan M; Wassmann, Katja

2017-09-25

A key feature of meiosis is the step-wise removal of cohesin, the protein complex holding sister chromatids together, first from arms in meiosis I and then from the centromere region in meiosis II. Centromeric cohesin is protected by Sgo2 from Separase-mediated cleavage, in order to maintain sister chromatids together until their separation in meiosis II. Failures in step-wise cohesin removal result in aneuploid gametes, preventing the generation of healthy embryos. Here, we report that kinase activities of Bub1 and Mps1 are required for Sgo2 localisation to the centromere region. Mps1 inhibitor-treated oocytes are defective in centromeric cohesin protection, whereas oocytes devoid of Bub1 kinase activity, which cannot phosphorylate H2A at T121, are not perturbed in cohesin protection as long as Mps1 is functional. Mps1 and Bub1 kinase activities localise Sgo2 in meiosis I preferentially to the centromere and pericentromere respectively, indicating that Sgo2 at the centromere is required for protection.In meiosis I centromeric cohesin is protected by Sgo2 from Separase-mediated cleavage ensuring that sister chromatids are kept together until their separation in meiosis II. Here the authors demonstrate that Bub1 and Mps1 kinase activities are required for Sgo2 localisation to the centromere region.

Biomonitoring of genotoxic risk in radar facility workers: comparison of the comet assay with micronucleus assay and chromatid breakage assay

International Nuclear Information System (INIS)

Garaj-Vrhovac, V.; Kopjar, N.

2003-01-01

Genotoxic risks of occupational exposure in a radar facility were evaluated by using alkaline comet assay, micronucleus assay and chromatid breakage assay on peripheral blood leukocytes in exposed subjects and corresponding controls. Results show that occupational exposure to microwave radiation correlates with an increase of genome damage in somatic cells. The levels of DNA damage in exposed subjects determined by using alkaline comet assay were increased compared to control and showed interindividual variations. Incidence of micronuclei was also significantly increased compared to baseline control values. After short exposure of cultured lymphocytes to bleomycin, cells of occupationally exposed subjects responded with high numbers of chromatid breaks. Although the level of chromosome damage generated by bleomycin varied greatly between individuals, in exposed subjects a significantly elevated number of chromatid breaks was observed. Our results support data reported in literature indicating that microwave radiation represents a potential DNA-damaging hazard. Alkaline comet assay is confirmed as a sensitive and highly reproducible technique for detection of primary DNA damage inflicted in somatic cells. Micronucleus assay was confirmed as reliable bio-markers of effect and chromatid breakage assay as sensitive bio-marker of individual cancer susceptibility. The results obtained also confirm the necessity to improve measures and to perform accurate health surveillance of individuals occupationally exposed to microwave radiation

Cytogenetic diagnosis of Roberts SC phocomelia syndrome: First report from Kashmir

Directory of Open Access Journals (Sweden)

Tahir M. Malla

2016-01-01

Full Text Available There are several syndromes in which specific mitotic chromosomal abnormalities can be seen, like premature centromere separation, premature (sister chromatid separation, and somatic aneuploidies. Identifications of such specific cytogenetic findings can be the key factor that leads towards the diagnosis of syndromes like Roberts SC phocomelia. The case presented here as Roberts SC phocomelia syndrome was identified as a child with multiple congenital anomalies and dysmorphic features. Conventional cytogenetic analysis of the case revealed premature sister chromatid separation. The premature centromeric separation was also confirmed by C banding analysis of the child. It is the first and the only case of Roberts SC phocomelia diagnosed from this part of the world. The present case report emphasizes the importance of conventional cytogenetics in the diagnosis of such syndromes.

Assessing Software Quality Through Visualised Cohesion Metrics

Directory of Open Access Journals (Sweden)

Timothy Shih

2001-05-01

Full Text Available Cohesion is one of the most important factors for software quality as well as maintainability, reliability and reusability. Module cohesion is defined as a quality attribute that seeks for measuring the singleness of the purpose of a module. The module of poor quality can be a serious obstacle to the system quality. In order to design a good software quality, software managers and engineers need to introduce cohesion metrics to measure and produce desirable software. A highly cohesion software is thought to be a desirable constructing. In this paper, we propose a function-oriented cohesion metrics based on the analysis of live variables, live span and the visualization of processing element dependency graph. We give six typical cohesion examples to be measured as our experiments and justification. Therefore, a well-defined, well-normalized, well-visualized and well-experimented cohesion metrics is proposed to indicate and thus enhance software cohesion strength. Furthermore, this cohesion metrics can be easily incorporated with software CASE tool to help software engineers to improve software quality.

Fulltext PDF

Indian Academy of Sciences (India)

Prakash

2010-02-03

Feb 3, 2010 ... proposed as a mechanism for brain hemispheric laterality specification ... By theory, sister chromatids of translocation-containing chromosomes are randomly segregated. ... the left and the other on the right side of the embryo.

Uncoupling of Sister Replisomes during Eukaryotic DNA Replication

NARCIS (Netherlands)

Yardimci, Hasan; Loveland, Anna B.; Habuchi, Satoshi; van Oijen, Antoine M.; Walter, Johannes C.

2010-01-01

The duplication of eukaryotic genomes involves the replication of DNA from multiple origins of replication. In S phase, two sister replisomes assemble at each active origin, and they replicate DNA in opposite directions. Little is known about the functional relationship between sister replisomes.

Scour in cohesive soils

Science.gov (United States)

2015-05-01

This study of scour in cohesive soils had two objectives. The first was to introduce and demonstrate a new ex situ erosion testing device (ESTD) that can mimic the near-bed flow of open channels to erode cohesive soils within a specified range of she...

Dynamics of Cohesive Sediments

DEFF Research Database (Denmark)

Johansen, Claus

The present thesis considers the transport processes of cohesive sediments. The cohesive sediment used in the laboratory experiments was kaolinite, a clay mineral, in order to be able to reproduce the individual experiments. In the first part of the thesis, the theoretical considerations regarding...

little sister: An Afro-Temporal Solo-Play.

Science.gov (United States)

De Berry, Misty

2017-07-03

little sister: An Afro-Temporal Solo-Play is at once a memory-scape and a mytho-biography set to poetry, movement, and mixed media. A performance poem spanning from the Antebellum South to present-moment Chicago, it tells the story of a nomadic spirit named little-she who shape-shifts through the memories and imaginings of her sister, the narrator. Through the characters little-she and the narrator, the solo-performance explores embodied ways to rupture and relieve the impact of macro forms of violence in the micro realm of the everyday. To this end, little sister witnesses and disrupts the legacy of violence in the lives of queer Black women through a trans-temporal navigation of everyday encounters within familial, small groups and intimate partner spaces.

Psychological characteristics of group cohesion athletes.

OpenAIRE

Sheriff Sarhan

2011-01-01

The basic components of group cohesion in sport teams. An analysis of publications on cohesion within the groups where an interconnection of individual goals of each participant group with common goals and the end result of teamwork. The concept of harmony in the team sports, where the rate of group cohesion is dependent on such integrative index as psychological climate. It is established that a number of athletes to achieve high results require high cohesion, unity, value-normative orientat...

Force Transmission Modes of Non-Cohesive and Cohesive Materials at the Critical State.

Science.gov (United States)

Wang, Ji-Peng

2017-08-31

This paper investigates the force transmission modes, mainly described by probability density distributions, in non-cohesive dry and cohesive wet granular materials by discrete element modeling. The critical state force transmission patterns are focused on with the contact model effect being analyzed. By shearing relatively dense and loose dry specimens to the critical state in the conventional triaxial loading path, it is observed that there is a unique critical state force transmission mode. There is a universe critical state force distribution pattern for both the normal contact forces and tangential contact forces. Furthermore, it is found that using either the linear Hooke or the non-linear Hertz model does not affect the universe force transmission mode, and it is only related to the grain size distribution. Wet granular materials are also simulated by incorporating a water bridge model. Dense and loose wet granular materials are tested, and the critical state behavior for the wet material is also observed. The critical state strength and void ratio of wet granular materials are higher than those of a non-cohesive material. The critical state inter-particle distribution is altered from that of a non-cohesive material with higher probability in relatively weak forces. Grains in non-cohesive materials are under compressive stresses, and their principal directions are mainly in the axial loading direction. However, for cohesive wet granular materials, some particles are in tension, and the tensile stresses are in the horizontal direction on which the confinement is applied. The additional confinement by the tensile stress explains the macro strength and dilatancy increase in wet samples.

INDUCTION OF DNA STRAND BREAKS BY TRIHALOMETHANES IN PRIMARY HUMAN LUNG EPITHELIAL CELLS

Science.gov (United States)

Abstract Trihalomethanes (TEMs) are disinfection by-products and suspected human carcinogens present in chlorinated drinking water. Previous studies have shown that many THMs induce sister chromatid exchanges and DNA strand breaks in human peripheral blood lymphocyte...

Interaction between a pair of gypsy insulators or between heterologous gypsy and Wari insulators modulates Flp site-specific recombination in Drosophila melanogaster.

Science.gov (United States)

Krivega, Margarita; Savitskaya, Ekaterina; Krivega, Ivan; Karakozova, Marina; Parshikov, Aleksander; Golovnin, Anton; Georgiev, Pavel

2010-08-01

Chromatin insulators block the action of transcriptional enhancers when interposed between an enhancer and a promoter. An Flp technology was used to examine interactions between Drosophila gypsy and Wari insulators in somatic and germ cells. The gypsy insulator consists of 12 binding sites for the Su(Hw) protein, while the endogenous Wari insulator, located on the 3' side of the white gene, is independent from the Su(Hw) protein. Insertion of the gypsy but not Wari insulator between FRT sites strongly blocks recombination between Flp dimers bound to FRT sites located on the same chromatid (recombination in cis) or in sister chromatids (unequal recombination in trans). At the same time, the interaction between Wari and gypsy insulators regulates the efficiency of Flp-mediated recombination. Thus, insulators may have a role in controlling interactions between distantly located protein complexes (not only those involved in transcriptional gene regulation) on the same chromosome or on sister chromatids in somatic and germ cells. We have also found that the frequency of Flp-mediated recombination between FRT sites is strongly dependent on the relative orientation of gypsy insulators. Taken together, our results indicate that the interactions between insulators can be visualized by Flp technology and that insulators may be involved in blocking undesirable interactions between proteins at the two-chromatid phase of the cell cycle.

The Lehman Sisters Hypothesis

NARCIS (Netherlands)

I.P. van Staveren (Irene)

2014-01-01

markdownabstract__Abstract__ This article explores the Lehman Sisters Hypothesis. It reviews empirical literature about gender differences in behavioral, experimental, and neuro-economics as well as in other fields of behavioral research. It discusses gender differences along three dimensions of

Organization of Sisters of Mercy During World War One

Directory of Open Access Journals (Sweden)

Sribnaia Anna

2014-10-01

Full Text Available The article examines the labour organization of Russian sisters of mercy during World War One. The author indicates two periods which took place before and after the February Revolution. Based on archive documents and offi cial publications the article describes general structure of Russian Red Cross Society institutions and basic principles of sisters of mercy communities’ work. It examines the rules of new sisters’ employment, their training, service assignment and professional duties. The emphasis is put on nurses’ work in wartime. During first years of war sisters’ position was stable. Due to specifi c hierarchy in the managing structure sisters’ work was productive and demanded. After the February Revolution the managing system changed drastically as well as the status of sisters of mercy and their reception in society. The author gives a thorough examination of sisters’ position after reorganization of Russian Red Cross Society. In time of political instability Russian sisters of mercy were able to organize themselves into one big organization thus creating All-Russian Union of Sisters of Mercy. This article for the first time ever implements into scientific research a huge amount of documents which allowed a signifi cant extension of views on Bolsheviks’ political approaches to Russian Red Cross Society and institution of sisters of mercy.

Team cohesion and team success in sport.

Science.gov (United States)

Carron, Albert V; Bray, Steven R; Eys, Mark A

2002-02-01

The main aim of this study was to examine the relationship between task cohesiveness and team success in elite teams using composite team estimates of cohesion. A secondary aim was to determine statistically the consistency (i.e. 'groupness') present in team members' perceptions of cohesion. Elite university basketball teams (n = 18) and club soccer teams (n = 9) were assessed for cohesiveness and winning percentages. Measures were recorded towards the end of each team's competitive season. Our results indicate that cohesiveness is a shared perception, thereby providing statistical support for the use of composite team scores. Further analyses indicated a strong relationship between cohesion and success (r = 0.55-0.67). Further research using multi-level statistical techniques is recommended.

Psychological characteristics of group cohesion athletes.

Directory of Open Access Journals (Sweden)

Sheriff Sarhan

2011-07-01

Full Text Available The basic components of group cohesion in sport teams. An analysis of publications on cohesion within the groups where an interconnection of individual goals of each participant group with common goals and the end result of teamwork. The concept of harmony in the team sports, where the rate of group cohesion is dependent on such integrative index as psychological climate. It is established that a number of athletes to achieve high results require high cohesion, unity, value-normative orientation, deep identification and responsibility for the results of the joint group activities.

The C-terminal domain of the Bloom syndrome DNA helicase is essential for genomic stability

Directory of Open Access Journals (Sweden)

Noonan James P

2001-07-01

Full Text Available Abstract Background Bloom syndrome is a rare cancer-prone disorder in which the cells of affected persons have a high frequency of somatic mutation and genomic instability. Bloom syndrome cells have a distinctive high frequency of sister chromatid exchange and quadriradial formation. BLM, the protein altered in BS, is a member of the RecQ DNA helicase family, whose members share an average of 40% identity in the helicase domain and have divergent N-terminal and C-terminal flanking regions of variable lengths. The BLM DNA helicase has been shown to localize to the ND10 (nuclear domain 10 or PML (promyelocytic leukemia nuclear bodies, where it associates with TOPIIIα, and to the nucleolus. Results This report demonstrates that the N-terminal domain of BLM is responsible for localization of the protein to the nuclear bodies, while the C-terminal domain directs the protein to the nucleolus. Deletions of the N-terminal domain of BLM have little effect on sister chromatid exchange frequency and chromosome stability as compared to helicase and C-terminal mutations which can increase SCE frequency and chromosome abnormalities. Conclusion The helicase activity and the C-terminal domain of BLM are critical for maintaining genomic stability as measured by the sister chromatid exchange assay. The localization of BLM into the nucleolus by the C-terminal domain appears to be more important to genomic stability than localization in the nuclear bodies.

Localization of two mammalian cyclin dependent kinases during mammalian meiosis

NARCIS (Netherlands)

Ashley, T.; Walpita, D.; de rooij, D. G.

2001-01-01

Mammalian meiotic progression, like mitotic cell cycle progression, is regulated by cyclins and cyclin dependent kinases (CDKs). However, the unique requirements of meiosis (homologous synapsis, reciprocal recombination and the dual divisions that segregate first homologues, then sister chromatids)

Single-cell template strand sequencing by Strand-seq enables the characterization of individual homologs

NARCIS (Netherlands)

Sanders, Ashley D; Falconer, Ester; Hills, Mark; Spierings, Diana C J; Lansdorp, Peter M.

The ability to distinguish between genome sequences of homologous chromosomes in single cells is important for studies of copy-neutral genomic rearrangements (such as inversions and translocations), building chromosome-length haplotypes, refining genome assemblies, mapping sister chromatid exchange

"Sister to the tailor"

DEFF Research Database (Denmark)

Simonton, Deborah

2017-01-01

Milliners, and their sisters, mantuamakers, modistes and marchandes de mode, were skilled artisans, businesswomen and tradeswomen. During the eighteenth century, they commandeered the high-class sewing that set fashion and created stars of their most famous, like Rose Bertrand, milliner to Marie...

Building International Relations for Children through Sister Schools.

Science.gov (United States)

Pryor, Carolyn B.

1992-01-01

Inspired by Sister Cities International and the NASSP's school-to-school exchange program, "sister school" pairings have proved to be workable educational programs with long-range impact on participants. Some post-cold war efforts include U.S.-USSR High School Academic Partnerships, Project Harmony, and Center for U.S.-USSR Initiatives.…

Developing Indicators of Territorial Cohesion

DEFF Research Database (Denmark)

Gallina, Andrea; Farrugia, Nadia

setting. The concept of territorial cohesion attaches importance to the diversity of the European territory which is seen as a key competitive advantage, the preservation of the European social model, and the ability of the citizens of Europe's nations and regions to be able to continue to live within...... (EU). The objective of territorial cohesion, which builds on the European Spatial Development Perspective (ESDP), is to help achieve a more balanced development by reducing existing disparities, avoiding territorial imbalances and by making sectoral policies, which have a spatial impact and regional...... policy more coherent. It also aims to improve territorial integration and encourage cooperation between regions. Territorial cohesion complements the notions of economic and social cohesion by translating the fundamental EU goal of a balanced competitiveness and sustainable development into a territorial...

[Two Dutch sisters in analysis with Freud].

Science.gov (United States)

Stroeken, Harry

2010-01-01

The author provides persuasive or at least plausible data for the identity of two patients recorded by Freud in his working season of 1910/11. They were two sisters, living in The Hague/Leiden, who came from a rich banker's family, the van der Lindens. Whereas the treatment does not seem to have led to any decisive improvement for the older of the two, it may have encouraged the younger sister to seek divorce.

Cohesion, Cracking, Dilation, and Flow -- Rheological Behavior of Cohesive Pharmaceutical Powders

Science.gov (United States)

Muzzio, Fernando

2007-03-01

Cohesive powders can be loosely defined as systems where the attractive forced between particles exceed the average particle weight. Cohesive powder flow is interesting from a wide range of reasons. Their main characteristic, intermittence, is evidenced both in the interruption of flow out of hoppers (a mundane issue causing great annoyance to industrial practitioners) and in the sudden avalanching of snow and dirt that has terrified and terrified mankind since the dawn of time. At the present time, our ability to predict either of these phenomena (and many more involving cohesive powders) is very limited, primarily due to an incomplete understanding of their constitutive behavior. To wit, consider just a simple fact: a flowing powder never has constant density. Equations describing the relationship between velocity, shear, stress, and density are rudimentary at best. Computational and experimental approaches for characterizing flow behavior are in their infancy. In this talk, I will describe some recent progress achieved at Rutgers by our group. New instruments have been developed to determine simultaneously powder density and cohesive flow effects. Extensive measurements have been carried out focusing on pharmaceutical blends. These results have been used to fine-tune computational models that accurately predict dilation, flow in drums, and flow in hoppers. Impact of these observations for pharmaceutical manufacturing applications will be discussed in some detail.

Transfer and Cohesion in Interdisciplinary Education

Directory of Open Access Journals (Sweden)

Søren Harnow Klausen

2014-06-01

Full Text Available One of the great challenges of interdisciplinary education is to create sufficient cohesion between disciplines. It is suggested that cohesion depends on the transfer of knowledge (in a broad sense, which includes skill and competences among the disciplines involved. Some of the most characteristic types of such transfer are identified and analyzed: Transfer of factual knowledge, theories, methods, models, skills, modes of collaboration and organization, meta-competences, disciplinary self-consciousness, problem selection, framework construction and motivation. Though some of these types of transfer may have a greater or smaller potential for creating cohesion, different kinds of cohesion may serve different interests, and there is no reason to assume that e.g. joint problem solving or theoretical integration should be more conducive to cohesion than e.g. contributions to motivation or disciplinary self-consciousness.

New trends and techniques in chromosome aberration analysis

International Nuclear Information System (INIS)

Bender, M.A.

1978-01-01

The following topics are discussed: automation of chromosome analysis; storage of fixed cells from cultures of lymphocytes obtained routinely during periodic employee medical examinations; analysis of banded chromosomes; identification of first division metaphases; sister chromatid exchange; and patterns of aberration induction

Looping in on Ndc80 - how does a protein loop at the kinetochore control chromosome segregation?

DEFF Research Database (Denmark)

Nilsson, Jakob

2012-01-01

Segregation of chromosomes during mitosis requires the interaction of dynamic microtubules with the kinetochore, a large protein structure established on the centromere region of sister chromatids. The core microtubule-binding activity of the kinetochore resides in the KMN network, an outer...

BLM helicase suppresses recombination at G-quadruplex motifs in transcribed genes

NARCIS (Netherlands)

van Wietmarschen, Niek; Merzouk, Sarra; Halsema, Nancy; Spierings, Diana C J; Guryev, Victor; Lansdorp, Peter M

2018-01-01

Bloom syndrome is a cancer predisposition disorder caused by mutations in the BLM helicase gene. Cells from persons with Bloom syndrome exhibit striking genomic instability characterized by excessive sister chromatid exchange events (SCEs). We applied single-cell DNA template strand sequencing

Characterization of the NTPR and BD1 interacting domains of the human PICH-BEND3 complex

DEFF Research Database (Denmark)

Pitchai, Ganesha P; Hickson, Ian D; Streicher, Werner

2016-01-01

Chromosome integrity depends on DNA structure-specific processing complexes that resolve DNA entanglement between sister chromatids. If left unresolved, these entanglements can generate either chromatin bridging or ultrafine DNA bridging in the anaphase of mitosis. These bridge structures are def...

H4K20me0 marks post-replicative chromatin and recruits the TONSL–MMS22L DNA repair complex

DEFF Research Database (Denmark)

Saredi, Giulia; Huang, Hongda; Hammond, Colin M

2016-01-01

After DNA replication, chromosomal processes including DNA repair and transcription take place in the context of sister chromatids. While cell cycle regulation can guide these processes globally, mechanisms to distinguish pre- and post-replicative states locally remain unknown. Here we reveal...

High local carcinogenic activity of 1,3-dimethyl-3-phenyl-1-nitrosourea and its inactivation by intravenous application in rats: comparison of in vivo findings with the in vitro direct and a combined in vivo/in vitro sister chromatid exchange assay in V79-E cells.

Science.gov (United States)

Thust, R; Martin, J; Mendel, J; Schreiber, D

1987-02-01

1,3-Dimethyl-3-phenyl-1-nitrosourea (DMPNU) is a very potent local carcinogen in rats and induces a 100% frequency of forestomach carcinomas when applied i.g. in two different dosages (10 applications of 0.3 or 0.03 mmol/kg body wt, respectively, at 14-day intervals), but it is inactive upon i.v. administration (10 applications of 0.03 mmol/kg body wt at 14-day intervals). By means of the direct sister chromatid exchange (SCE) assay in V79-E cells in the presence of rat blood, serum or plasma, respectively, as well as by a 'host-mediated' SCE assay (in which the agent was given i.v. to rats, and blood taken from the animal was checked for the recovery of genotoxic activity in cell cultures), we tried to elucidate the unexpected lack of carcinogenic activity of i.v. DMPNU. The direct SCE assay revealed a drastic reduction of DMPNU genotoxicity by rat blood, serum or plasma, respectively, which is abolished by the esterase inhibitor diisopropylfluorophosphate. In the 'host-mediated' SCE assay a genotoxic activity of DMPNU was only recoverable after a very high i.v. dose and when the blood added to the cell cultures had been taken from the rat heart within 1 min after DMPNU administration in vivo. 1-Methyl-1-nitrosourea (MNU) and 1-methyl-3-phenyl-1-nitrosourea (MPNU) were used as positive controls in these experiments and also gave a lower response than theoretically expected, but the relative loss of activity with the latter compounds was much lower than with DMPNU. It is assumed that an esterase in rat blood effectively decomposes this trisubstituted nitrosourea. Problems of the novel 'host-mediated' SCE assay are discussed.

Sustaining exercise participation through group cohesion.

Science.gov (United States)

Estabrooks, P A

2000-04-01

The general hypothesis to be examined by this article is that increased group cohesion leads to an increase in adherence to an exercise program over time. Although preliminary research is promising, there is a need for further research aimed at examining the model of group development in exercise classes, the impact of group cohesion on both group and individual exercise behavior, and the measurement of group cohesion.

Smc1β is required for activation of SAC during mouse oocyte meiosis.

Science.gov (United States)

Miao, Yilong; Zhou, Changyin; Cui, Zhaokang; Dai, Xiaoxin; Zhang, Mianqun; Lu, Yajuan; Xiong, Bo

2017-03-19

Smc1β is a meiosis-specific cohesin subunit that is essential for sister chromatid cohesion and DNA recombination. Previous studies have shown that Smc1β-deficient mice in both sexes are sterile. Ablation of Smc1β during male meiosis leads to the blockage of spermatogenesis in pachytene stage, and ablation of Smc1β during female meiosis generates a highly error-prone oocyte although it could develop to metaphase II stage. However, the underlying mechanisms regarding how Smc1β maintains the correct meiotic progression in mouse oocytes have not been clearly defined. Here, we find that GFP-fused Smc1β is expressed and localized to the chromosomes from GV to MII stages during mouse oocyte meiotic maturation. Knockdown of Smc1β by microinjection of gene-specific morpholino causes the impaired spindle apparatus and chromosome alignment which are highly correlated with the defective kinetochore-microtubule attachments, consequently resulting in a prominently higher incidence of aneuploid eggs. In addition, the premature extrusion of polar bodies and escape of metaphase I arrest induced by low dose of nocodazole treatment in Smc1β-depleted oocytes indicates that Smc1β is essential for activation of spindle assembly checkpoint (SAC) activity. Collectively, we identify a novel function of Smc1β as a SAC participant beyond its role in chromosome cohesion during mouse oocyte meiosis.

The frequency of chromatide aberrations as a function of radiation dose estimated by the number of dicentrics found by the cytogenetic analysis of lymphocytes in subjects affected by the Chernobyl accident

International Nuclear Information System (INIS)

Nugis, V.Yu.; Chirkov, A.A.

1990-01-01

A study was made of the frequency of chromatide aberrations in lymphocyte culture of subjects affected by the Chernobyl accident as a function of dose estimated by the incidence of dicentrics. The average number of chromatide aberrations was nearly the same within the dose range from 0 to 5 Gy exhibiting a tendency towards growth with dose. A high individual variability of the chromatide aberration frequency was observed

Terminalia catappa , an anticlastogenic agent against MMS induced ...

African Journals Online (AJOL)

Subjects: Anticarcinogenic potential of methanolic extract of T. catappa has been tested against the carcinogenicity induced by methyl methanesulfonate in the in vitro and in vivo models. Methods: The parameters for evaluation included chromosomal aberrations (CA), sister chromatid exchanges (SCEs) and replication ...

DNA template strand sequencing of single-cells maps genomic rearrangements at high resolution

NARCIS (Netherlands)

Falconer, Ester; Hills, Mark; Naumann, Ulrike; Poon, Steven S. S.; Chavez, Elizabeth A.; Sanders, Ashley D.; Zhao, Yongjun; Hirst, Martin; Lansdorp, Peter M.

DNA rearrangements such as sister chromatid exchanges (SCEs) are sensitive indicators of genomic stress and instability, but they are typically masked by single-cell sequencing techniques. We developed Strand-seq to independently sequence parental DNA template strands from single cells, making it

Roberts syndrome: clinical and cytogenetic aspects

OpenAIRE

Mann, N P; Fitzsimmons, J; Fitzsimmons, E; Cooke, P

1982-01-01

Roberts syndrome is reported in two sibs of consanguineous parents. Both infants had severe tetraphocomelia, facial clefting, and other serious malformations. In addition they were found to have an unusual cytogenetic abnormality with distortion of the normal sister chromatid relationship in many chromosomes.

Amphitelic orientation of centromeres at metaphase I is an important ...

Indian Academy of Sciences (India)

2014-07-31

Jul 31, 2014 ... sion of sister chromatids at AI without the second meiotic division (Matsuoka and .... level of chromosome pairing with 0.28 bivalents/PMC was seen in 20% of the ... The union of two such unreduced games could result in the ...

Biochemical evidence for deficient DNA repair leading to enhanced G2 chromatid radiosensitivity and susceptibility to cancer

International Nuclear Information System (INIS)

Gantt, R.; Parshad, R.; Price, F.M.; Sanford, K.K.

1986-01-01

Human tumor cells and cells from cancer-prone individuals, compared with those from normal individuals, show a significantly higher incidence of chromatid breaks and gaps seen in metaphase cells immediately after G2 X irradiation. Previous studies with DNA repair-deficient mutants and DNA repair inhibitors strongly indicate that the enhancement results from a G2 deficiency(ies) in DNA repair. We report here biochemical evidence for a DNA repair deficiency that correlates with the cytogenetic studies. In the alkaline elution technique, after a pulse label with radioactive thymidine in the presence of 3-acetylaminobenzamide (a G2-phase blocker) and X irradiation, DNA from tumor or cancer-prone cells elutes more rapidly during the postirradiation period than that from normal cells. These results indicate that the DNA of tumor and cancer-prone cells either repairs more slowly or acquires more breaks than that of normal cells; breaks can accumulate during incomplete or deficient repair processes. The kinetic difference between normal and tumor or cancer-prone cells in DNA strand-break repair reaches a maximum within 2 h, and this maximum corresponds to the kinetic difference in chromatid aberration incidence following X irradiation reported previously. These findings support the concept that cells showing enhanced G2 chromatid radiosensitivity are deficient in DNA repair. The findings could also lead to a biochemical assay for cancer susceptibility

Sister Mary Emil Penet, I.H.M.: Founder of the Sister Formation Conference

Science.gov (United States)

Glisky, Joan

2006-01-01

Mary Emil Penet, I.H.M., (1916-2001) used her talents and charisma to shape the first national organization of American women religious, the Sister Formation Conference (SFC; 1954-1964), facilitating the integrated intellectual, spiritual, psychological, and professional development of vowed women religious. In the decade preceding Vatican II, her…

Certain tryptophan photoproducts are inhibitors of cytochrome P450-dependent mutagenicity

International Nuclear Information System (INIS)

Rannug, U.; Agurell, E.; Cederberg, H.; Rannug, A.

1992-01-01

Two photoproducts, derived from UV-irradiation of the amino acid L-tryptophan and with high Ah (TCDD) receptor binding affinity, were tested for genotoxic and antimutagenic effects. The two indolo[3,2-b]carbazole derivatives, with the molecular weights of 284 and 312, respectively, were tested in Saccharomyces cerevisiae strain D7 for mitotic gene conversion and reverse mutation and in strain RS112 for sister chromatid conversion and gene conversion. No significant (P > 0.05) genotoxic effects were found in strain D7, while strain RS112 showed a small but significant increase in the frequency of sister chromatid conversions. In Chinese hamster ovary (CHO) cells the two compounds induced a statistically significant but less than twofold increase in the frequency of sister chromatid exchanges (SCE). No mutations were detected when the compounds were tested in Salmonella tphimurium strains TA98 and TA100. However, both 284 and 312 acted as antimutagens on strain TA100+S9 in the presence of benzo(a)pyrene. The decrease in mutagenicity by the most potent compound 284 was 20 revertants/nmol. This effect could be explained by an inhibitory effect on the cytochrome P450-dependent ethoxyresorufin O-deethylase (EROD) activity as seen in rat hepatocytes. The two compounds were also tested with hamster cells expressing rat cytochrome P-4501A1. The results support the conclusion that this cytochrome P-450 isozyme is inhibited by the tryptophan photoproducts. Similar results were also seen with two other high affinity Ah receptor ligands the quinazolinocarboline alkaloids rutaecapine and dehydrorutaecarpine. 20 refs., 3 figs., 4 tabs

Thrombopoietin-induced Polyploidization of Bone Marrow Megakaryocytes Is Due to a Unique Regulatory Mechanism in Late Mitosis

Science.gov (United States)

Nagata, Yuka; Muro, Yoshinao; Todokoro, Kazuo

1997-01-01

Megakaryocytes undergo a unique differentiation program, becoming polyploid through repeated cycles of DNA synthesis without concomitant cell division. However, the mechanism underlying this polyploidization remains totally unknown. It has been postulated that polyploidization is due to a skipping of mitosis after each round of DNA replication. We carried out immunohistochemical studies on mouse bone marrow megakaryocytes during thrombopoietin- induced polyploidization and found that during this process megakaryocytes indeed enter mitosis and progress through normal prophase, prometaphase, metaphase, and up to anaphase A, but not to anaphase B, telophase, or cytokinesis. It was clearly observed that multiple spindle poles were formed as the polyploid megakaryocytes entered mitosis; the nuclear membrane broke down during prophase; the sister chromatids were aligned on a multifaced plate, and the centrosomes were symmetrically located on either side of each face of the plate at metaphase; and a set of sister chromatids moved into the multiple centrosomes during anaphase A. We further noted that the pair of spindle poles in anaphase were located in close proximity to each other, probably because of the lack of outward movement of spindle poles during anaphase B. Thus, the reassembling nuclear envelope may enclose all the sister chromatids in a single nucleus at anaphase and then skip telophase and cytokinesis. These observations clearly indicate that polyploidization of megakaryocytes is not simply due to a skipping of mitosis, and that the megakaryocytes must have a unique regulatory mechanism in anaphase, e.g., factors regulating anaphase such as microtubule motor proteins might be involved in this polyploidization process. PMID:9334347

Transcriptional dysregulation in NIPBL and cohesin mutant human cells.

Directory of Open Access Journals (Sweden)

Jinglan Liu

2009-05-01

Full Text Available Cohesin regulates sister chromatid cohesion during the mitotic cell cycle with Nipped-B-Like (NIPBL facilitating its loading and unloading. In addition to this canonical role, cohesin has also been demonstrated to play a critical role in regulation of gene expression in nondividing cells. Heterozygous mutations in the cohesin regulator NIPBL or cohesin structural components SMC1A and SMC3 result in the multisystem developmental disorder Cornelia de Lange Syndrome (CdLS. Genome-wide assessment of transcription in 16 mutant cell lines from severely affected CdLS probands has identified a unique profile of dysregulated gene expression that was validated in an additional 101 samples and correlates with phenotypic severity. This profile could serve as a diagnostic and classification tool. Cohesin binding analysis demonstrates a preference for intergenic regions suggesting a cis-regulatory function mimicking that of a boundary/insulator interacting protein. However, the binding sites are enriched within the promoter regions of the dysregulated genes and are significantly decreased in CdLS proband, indicating an alternative role of cohesin as a transcription factor.

The role of STAG2 in bladder cancer.

Science.gov (United States)

Aquila, Lanni; Ohm, Joyce; Woloszynska-Read, Anna

2018-05-01

Stromal Antigen 2 (STAG2) is one of four components of the cohesin complex and predominantly functions in sister chromatid cohesion and segregation. STAG2 is the most frequently mutated cohesin subunit and was recently identified as a gene that is commonly altered in bladder cancer. The significance of these mutations remains controversial. Some studies associate loss of STAG2 expression with low stage and low grade bladder tumors, as well as with improved clinical outcomes. In other cases, STAG2 inactivation has been shown to be a predictor of worse outcome for these patients. The role of STAG2 in aneuploidy also remains controversial. Loss of STAG2 is associated with significant changes in chromosome number in certain cell lines, while in others, aneuploidy is not induced or results remain inconclusive. At this time, little is known about the influence of STAG2 on cellular migration, invasion, proliferation, and cell death, and such studies are required to determine the role of STAG2 in bladder cancer and other malignancies. Copyright © 2018 Elsevier Ltd. All rights reserved.

RAD21L, a novel cohesin subunit implicated in linking homologous chromosomes in mammalian meiosis.

Science.gov (United States)

Lee, Jibak; Hirano, Tatsuya

2011-01-24

Cohesins are multi-subunit protein complexes that regulate sister chromatid cohesion during mitosis and meiosis. Here we identified a novel kleisin subunit of cohesins, RAD21L, which is conserved among vertebrates. In mice, RAD21L is expressed exclusively in early meiosis: it apparently replaces RAD21 in premeiotic S phase, becomes detectable on the axial elements in leptotene, and stays on the axial/lateral elements until mid pachytene. RAD21L then disappears, and is replaced with RAD21. This behavior of RAD21L is unique and distinct from that of REC8, another meiosis-specific kleisin subunit. Remarkably, the disappearance of RAD21L at mid pachytene correlates with the completion of DNA double-strand break repair and the formation of crossovers as judged by colabeling with molecular markers, γ-H2AX, MSH4, and MLH1. RAD21L associates with SMC3, STAG3, and either SMC1α or SMC1β. Our results suggest that cohesin complexes containing RAD21L may be involved in synapsis initiation and crossover recombination between homologous chromosomes.

Investigating Some Technical Issues on Cohesive Zone Modeling of Fracture

Science.gov (United States)

Wang, John T.

2011-01-01

This study investigates some technical issues related to the use of cohesive zone models (CZMs) in modeling fracture processes. These issues include: why cohesive laws of different shapes can produce similar fracture predictions; under what conditions CZM predictions have a high degree of agreement with linear elastic fracture mechanics (LEFM) analysis results; when the shape of cohesive laws becomes important in the fracture predictions; and why the opening profile along the cohesive zone length needs to be accurately predicted. Two cohesive models were used in this study to address these technical issues. They are the linear softening cohesive model and the Dugdale perfectly plastic cohesive model. Each cohesive model constitutes five cohesive laws of different maximum tractions. All cohesive laws have the same cohesive work rate (CWR) which is defined by the area under the traction-separation curve. The effects of the maximum traction on the cohesive zone length and the critical remote applied stress are investigated for both models. For a CZM to predict a fracture load similar to that obtained by an LEFM analysis, the cohesive zone length needs to be much smaller than the crack length, which reflects the small scale yielding condition requirement for LEFM analysis to be valid. For large-scale cohesive zone cases, the predicted critical remote applied stresses depend on the shape of cohesive models used and can significantly deviate from LEFM results. Furthermore, this study also reveals the importance of accurately predicting the cohesive zone profile in determining the critical remote applied load.

Three Sisters Dam modifications and performance

Energy Technology Data Exchange (ETDEWEB)

Courage, L.J.R. [Monenco AGRA Inc., Calgary, AB (Canada)

1995-12-31

Recent modifications and maintenance carried out at the Three Sisters Dam, in the Alberta Rockies south of the town of Canmore, were described. A detailed account was given of the dam`s geological setting, its abnormally high leakage through the foundation and its sinkhole activity. Results of studies aimed at finding the cause of leakage and sinkhole occurrences were reviewed. Modifications made to the dam since 1951 were detailed, as were modifications to handle probable maximum flood levels. Three approaches for estimating failure probabilities after identification of failure modes were described. The overall conclusion was that based on constant leakage, no settlement in the dam, penstocks, or the powerhouse since construction, the Three Sisters Dam was stable. 1 ref.

Reconstitution of Nucleosomes with Differentially Isotope-labeled Sister Histones.

Science.gov (United States)

Liokatis, Stamatios

2017-03-26

Asymmetrically modified nucleosomes contain the two copies of a histone (sister histones) decorated with distinct sets of Post-translational Modifications (PTMs). They are newly identified species with unknown means of establishment and functional implications. Current analytical methods are inadequate to detect the copy-specific occurrence of PTMs on the nucleosomal sister histones. This protocol presents a biochemical method for the in vitro reconstitution of nucleosomes containing differentially isotope-labeled sister histones. The generated complex can be also asymmetrically modified, after including a premodified histone pool during refolding of histone subcomplexes. These asymmetric nucleosome preparations can be readily reacted with histone-modifying enzymes to study modification cross-talk mechanisms imposed by the asymmetrically pre-incorporated PTM using nuclear magnetic resonance (NMR) spectroscopy. Particularly, the modification reactions in real-time can be mapped independently on the two sister histones by performing different types of NMR correlation experiments, tailored for the respective isotope type. This methodology provides the means to study crosstalk mechanisms that contribute to the formation and propagation of asymmetric PTM patterns on nucleosomal complexes.

Auto consolidated cohesive sediments erosion

International Nuclear Information System (INIS)

Ternat, F.

2007-02-01

Pollutants and suspended matters of a river can accumulate into the sedimentary column. Once deposited, they are submitted to self-weight consolidation processes, ageing and burying, leading to an increase of their erosion resistance. Pollutant fluxes can be related to sedimentary fluxes, determined by threshold laws. In this work, an erosion threshold model is suggested by introducing a cohesion force into the usual force balance. A model of cohesion is developed on the basis of interactions between argillaceous cohesive particles (clays), particularly the Van der Waals force, whose parameterization is ensured by means of granulometry and porosity. Artificial erosion experiments were performed in a recirculating erosion flume with natural cored sediments where critical shear stress measurements were performed. Other analyses provided granulometry and porosity. The results obtained constitute a good database for the literature. The model is then applied to the experimental conditions and gives good agreement with measurements. An example of the accounting for self-weight consolidation processes is finally suggested, before finishing on a Mohr like diagram dedicated to soft cohesive sediment erosion. (author)

Group cohesion, task performance, and the experimenter expectancy effect.

NARCIS (Netherlands)

Hoogstraten, J.; Vorst, H.C.M.

1978-01-01

Studied the effects of cohesion on task fulfillment and explored the influence of task fulfillment on the initial level of cohesion. Within 4-person groups of undergraduates, cohesion was manipulated successfully by a triple procedure. The level of cohesion was ascertained directly after the

Coaches' Perceptions of Team Cohesion in Paralympic Sports.

Science.gov (United States)

Falcão, William R; Bloom, Gordon A; Loughead, Todd M

2015-07-01

The purpose of this study was to investigate Paralympic coaches' perceptions of team cohesion. Seven head coaches of summer and winter Canadian Paralympic sport teams participated in the study. Four participants coached individual sports and 3 coached team sports. Data were collected using semistructured interviews and analyzed using thematic analysis. The results addressed the coaches' perceptions of cohesion in the Paralympic sport setting and strategies used to foster cohesion with their teams. Participants described using techniques and strategies for enhancing cohesion that were similar to those in nondisability sport, such as task-related activities, goal setting, and regularly communicating with their athletes. They also listed how cohesion was distinct to the Paralympic setting, such as the importance of interpersonal activities to build social cohesion. The implications of these results for coaching athletes with a disability are also presented.

GNE Myopathy in Turkish Sisters with a Novel Homozygous Mutation

Science.gov (United States)

Diniz, Gulden; Secil, Yaprak; Ceylaner, Serdar; Tokucoglu, Figen; Türe, Sabiha; Celebisoy, Mehmet; İncesu, Tülay Kurt; Akhan, Galip

2016-01-01

Background. Hereditary inclusion body myopathy is caused by biallelic defects in the GNE gene located on chromosome 9p13. It generally affects adults older than 20 years of age. Methods and Results. In this study, we present two Turkish sisters with progressive myopathy and describe a novel mutation in the GNE gene. Both sisters had slightly higher levels of creatine kinase (CK) and muscle weakness. The older sister presented at 38 years of age with an inability to climb steps, weakness, and a steppage gait. Her younger sister was 36 years old and had similar symptoms. The first symptoms of the disorder were seen when the sisters were 30 and 34 years old, respectively. The muscle biopsy showed primary myopathic features and presence of rimmed vacuoles. DNA analysis demonstrated the presence of previously unknown homozygous mutations [c.2152 G>A (p.A718T)] in the GNE genes. Conclusion. Based on our literature survey, we believe that ours is the first confirmed case of primary GNE myopathy with a novel missense mutation in Turkey. These patients illustrate that the muscle biopsy is still an important method for the differential diagnosis of vacuolar myopathies in that the detection of inclusions is required for the definitive diagnosis. PMID:27298745

Geographic variance of cardiovascular risk factors among community women: the national Sister to Sister campaign.

Science.gov (United States)

Jarvie, Jennifer L; Johnson, Caitlin E; Wang, Yun; Wan, Yun; Aslam, Farhan; Athanasopoulos, Leonidas V; Pollin, Irene; Foody, JoAnne M

2011-01-01

There are substantial variations in cardiovascular disease (CVD) risk and outcomes among women. We sought to determine geographic variation in risk factor prevalence in a contemporary sample of U.S. women. Using 2008-2009 Sister to Sister (STS) free heart screening data from 17 U.S. cities, we compared rates of obesity (body mass index [BMI] ≥30 kg/m(2)), hypertension (HTN ≥140/90 mm Hg), low high-density lipoprotein cholesterol (HDL-C cities had higher rates of hyperglycemia and low HDL-C. In a large, community-based sample of women nationwide, this comprehensive analysis shows remarkable geographic variation in risk factors, which provides opportunities to improve and reduce a woman's CVD risk. Further investigation is required to understand the reasons behind such variation, which will provide insight toward tailoring preventive interventions to narrow gaps in CVD risk reduction in women.

Micromechanical modeling and inverse identification of damage using cohesive approaches

International Nuclear Information System (INIS)

Blal, Nawfal

2013-01-01

In this study a micromechanical model is proposed for a collection of cohesive zone models embedded between two each elements of a standard cohesive-volumetric finite element method. An equivalent 'matrix-inclusions' composite is proposed as a representation of the cohesive-volumetric discretization. The overall behaviour is obtained using homogenization approaches (Hashin Shtrikman scheme and the P. Ponte Castaneda approach). The derived model deals with elastic, brittle and ductile materials. It is available whatever the triaxiality loading rate and the shape of the cohesive law, and leads to direct relationships between the overall material properties and the local cohesive parameters and the mesh density. First, rigorous bounds on the normal and tangential cohesive stiffnesses are obtained leading to a suitable control of the inherent artificial elastic loss induced by intrinsic cohesive models. Second, theoretical criteria on damageable and ductile cohesive parameters are established (cohesive peak stress, critical separation, cohesive failure energy,... ). These criteria allow a practical calibration of the cohesive zone parameters as function of the overall material properties and the mesh length. The main interest of such calibration is its promising capacity to lead to a mesh-insensitive overall response in surface damage. (author) [fr

Terminalia arjuna, a herbal remedy against environmental ...

African Journals Online (AJOL)

... 429 due to AFB1 to 141 due to 5th concentration of Terminalia extracts at 32 h of exposure. Conclusion: The ameliorating potential of Terminalia extracts was dose and time dependant. Keywords: Ayurvedic medicine; Carcinogen; Chromosomal aberration; Sister chromatid exchange; Replication index; Terminalia arjuna ...

Assessment of drug induced genotoxicity in gastric cancer patients ...

African Journals Online (AJOL)

Cytogenetic studies were carried out in peripheral blood lymphocytes of study population by adopting standard cytogenetic protocols such as (a) chromosomal aberrations (CA) and (b) sister chromatid exchanges (SCE). Student t- test was adopted to analyze the statistical significance. An increased pattern in the frequency ...

Relationship between group cohesion and anxiety in soccer.

Science.gov (United States)

Borrego, Carla Chicau; Cid, Luis; Silva, Carlos

2012-10-01

Group cohesion in sport is a widely spread theme today. Research has found cohesion to be influenced by several individual and group components. Among the cognitive variables that relate to cohesion we found competitive anxiety. The purpose of this study was to examine the relation between task cohesion (ATG-T, and GI-T) and competitive state anxiety (A-state), and also if there would be a relation between cohesion and self-confidence. Participants were 366 football players of both genders male and female, aged between 15 to 23 years old, from Portugal's championships. Cohesion was measured using the Portuguese version of the Group Environment Questionnaire, and to assess competitive anxiety, we used the Portuguese version of the Competition State Anxiety Inventory 2. Our results show that female athletes report experiencing more cognitive anxiety and less self-confidence than male athletes. Only cognitive anxiety relates in a significantly negative way with the perception of cohesion (GI-T e ATG-T) in the total number of participants and in male athletes. Relatively to the somatic anxiety, it only relates negatively with the perception of the integration of the group in the total number of participants and in the male gender.

Distinct roles of FANCO/RAD51C in DNA damage signaling and repair: implications for fanconi anemia and breast cancer susceptibility

International Nuclear Information System (INIS)

Nagaraju, G.; Somyajit, K.; Subramanya, S.

2012-01-01

Unrepaired or misrepaired chromosomal double-strand breaks (DSBs) can cause gross chromosomal rearrangements which eventually can lead to tumorigenesis through inactivation of tumor suppressor genes or activation of oncogenes. There are two major mechanisms of DSB repair: non-homologous end joining (NHEJ) and homologous recombination (HR). DSBs that are generated during S and G2 phase of the cell are preferentially repaired by sister chromatid recombination (SCR), an HR pathway that utilizes neighboring sister chromatid as a template. Since the copied information is accurate, SCR is potentially an error-free pathway. HR also plays a critical role in the repair of daughter strand gaps (DSGs) that arise as a result of replication fork stalling and facilitates replication fork recovery. Furthermore, in collaboration with nucleotide excision repair and translesion synthesis, HR is involved in the repair of DNA interstrand cross-links (ICLs). Thus, HR is important for the maintenance of genome integrity and its dysfunction can lead to various genetic disorders and cancer

Mutations in genes encoding condensin complex proteins cause microcephaly through decatenation failure at mitosis.

Science.gov (United States)

Martin, Carol-Anne; Murray, Jennie E; Carroll, Paula; Leitch, Andrea; Mackenzie, Karen J; Halachev, Mihail; Fetit, Ahmed E; Keith, Charlotte; Bicknell, Louise S; Fluteau, Adeline; Gautier, Philippe; Hall, Emma A; Joss, Shelagh; Soares, Gabriela; Silva, João; Bober, Michael B; Duker, Angela; Wise, Carol A; Quigley, Alan J; Phadke, Shubha R; Wood, Andrew J; Vagnarelli, Paola; Jackson, Andrew P

2016-10-01

Compaction of chromosomes is essential for accurate segregation of the genome during mitosis. In vertebrates, two condensin complexes ensure timely chromosome condensation, sister chromatid disentanglement, and maintenance of mitotic chromosome structure. Here, we report that biallelic mutations in NCAPD2, NCAPH, or NCAPD3, encoding subunits of these complexes, cause microcephaly. In addition, hypomorphic Ncaph2 mice have significantly reduced brain size, with frequent anaphase chromatin bridge formation observed in apical neural progenitors during neurogenesis. Such DNA bridges also arise in condensin-deficient patient cells, where they are the consequence of failed sister chromatid disentanglement during chromosome compaction. This results in chromosome segregation errors, leading to micronucleus formation and increased aneuploidy in daughter cells. These findings establish "condensinopathies" as microcephalic disorders, with decatenation failure as an additional disease mechanism for microcephaly, implicating mitotic chromosome condensation as a key process ensuring mammalian cerebral cortex size. © 2016 Martin et al.; Published by Cold Spring Harbor Laboratory Press.

Adaptive response induced by low concentrations of MMC in human peripheral lymphocytes

International Nuclear Information System (INIS)

Sun Shuqing; Wang Bin; Jiang Jie

1998-01-01

Samples of cultured human peripheral lymphocytes were pre-treated with mitomycin C (MMC) in concentrations of 0.01∼0.1 μg/mL at 34 h of incubation and then exposed to 1.5 Gy of X-rays. Chromosome aberrations, sister chromatid exchanges and micronuclei for these lymphocytes were observed. The results show that the chromosome aberration rates for lymphocytes pre-treated with MMC in concentrations of 0.5 and 0.075 μg/mL and the frequencies of sister chromatid exchanges for lymphocytes pre-treated with MMC in concentrations of 0.01 μg/mL were significantly lower than their own expected values but the rates of micronuclei for lymphocytes pre-treated with MMC in concentrations of 0.05, 0.075 and 0.1 μg/mL were significantly higher than the expected values. Such results suggest that for studying the cross resistance of lymphocytes to chemicals and ionizing radiation, inconsistent conclusions may be obtained if different endpoints are based on

Biomonitoring of genotoxic exposure among stainless steel welders

DEFF Research Database (Denmark)

Knudsen, Lisbeth E.; Boisen, T; Christensen, J M

1992-01-01

A biosurvey in the Danish metal industry measured the genotoxic exposure from stainless steel welding. The study comprised measurements of chromosomal aberrations (CA), sister-chromatid exchanges (SCE), unscheduled DNA synthesis (UDS) in peripheral lymphocytes and serum immunoglobulin G. Environm......A biosurvey in the Danish metal industry measured the genotoxic exposure from stainless steel welding. The study comprised measurements of chromosomal aberrations (CA), sister-chromatid exchanges (SCE), unscheduled DNA synthesis (UDS) in peripheral lymphocytes and serum immunoglobulin G....... A higher frequency of chromosomal aberrations, classified as translocations, double minutes, exchanges and rings, was observed in stainless steel welders than in non-welders. SCE was lower in welders working with both MMA and TIG welding than in reference persons. N-Acetoxy-N-acetylaminofluorene (NA...... lymphocytes in exposed persons compared with non-exposed are suggested. MMA welding gave the highest exposure to chromium, an increased number of chromosomal aberrations and a decrease in SCE when compared with TIG welding. Consequently improvements in the occupational practice of stainless steel welding...

Environmental cohesion across the Hungarian-Croatian border

OpenAIRE

Varjú Viktor

2016-01-01

Environmental cohesion (as a new EU paradigm for a place-based interpretation of environmental justice) has a clear connection to territorial cohesion. Based on this idea, advantages for people can include an equitable distribution of environmental protection and access to environmental services. In non-EU countries regional environmental cohesion is used as an instrument to accelerate accession to the EU and it may be manifested as a declaration of environ...

Relating Cohesive Zone Model to Linear Elastic Fracture Mechanics

Science.gov (United States)

Wang, John T.

2010-01-01

The conditions required for a cohesive zone model (CZM) to predict a failure load of a cracked structure similar to that obtained by a linear elastic fracture mechanics (LEFM) analysis are investigated in this paper. This study clarifies why many different phenomenological cohesive laws can produce similar fracture predictions. Analytical results for five cohesive zone models are obtained, using five different cohesive laws that have the same cohesive work rate (CWR-area under the traction-separation curve) but different maximum tractions. The effect of the maximum traction on the predicted cohesive zone length and the remote applied load at fracture is presented. Similar to the small scale yielding condition for an LEFM analysis to be valid. the cohesive zone length also needs to be much smaller than the crack length. This is a necessary condition for a CZM to obtain a fracture prediction equivalent to an LEFM result.

Dam safety at Seven Sisters Generating Station

International Nuclear Information System (INIS)

Carson, R. W.; Gupta, R. C.

1996-01-01

A safety surveillance program for all hydraulic structures in Manitoba was first implemented in 1979, and updated in 1988. This contribution describes the current status of the program, and the nature of the issues that the program was designed to address. The Seven Sisters Station's dam on the Winnipeg River, about 90 km northeast of the City of Winnipeg, was used as an example. Extensive reviews of flood risks and downstream inundation potential at Seven Sisters' revealed a number of deficiencies; these findings will be incorporated into a corporate plan of overall remediation. Updating the program will also include efforts to ensure adherence to national dam safety guidelines. 5 figs

Effect of SPL (Spent Pot Liner) and its main components on root growth, mitotic activity and phosphorylation of Histone H3 in Lactuca sativa L.

Science.gov (United States)

Freitas, Aline Silva; Fontes Cunha, Isabela Martinez; Andrade-Vieira, Larissa Fonseca; Techio, Vânia Helena

2016-02-01

Spent Pot Liner (SPL) is a solid waste from the aluminum industry frequently disposed of in industrial landfills; it can be leached and contaminate the soil, sources of drinking water and plantations, and thus may pose a risk to human health and to ecosystems. Its composition is high variable, including cyanide, fluoride and aluminum salts, which are highly toxic and environmental pollutants. This study evaluated the effect of SPL and its main components on root growth and the mitosis of Lactuca sativa, by investigating the mechanisms of cellular and chromosomal alterations with the aid of immunolocalization. To this end, newly emerged roots of L. sativa were exposed to SPL and its main components (solutions of cyanide, fluoride and aluminum) and to calcium chloride (control) for 48h. After this, root length was measured and cell cycle was examined by means of conventional cytogenetics and immunolocalization. Root growth was inhibited in the treatments with SPL and aluminum; chromosomal and nuclear alterations were observed in all treatments. The immunolocalization evidenced normal dividing cells with regular temporal and spatial distribution of histone H3 phosphorylation at serine 10 (H3S10ph). However, SPL and its main components inhibited the phosphorylation of histone H3 at serine 10, inactivated pericentromeric regions and affected the cohesion of sister chromatids, thus affecting the arrangement of chromosomes in the metaphase plate and separation of chromatids in anaphase. In addition, these substances induced breaks in pericentromeric regions, characterized as fragile sites. Copyright © 2015 Elsevier Inc. All rights reserved.

Geologic map of Three Sisters volcanic cluster, Cascade Range, Oregon

Science.gov (United States)

Hildreth, Wes; Fierstein, Judy; Calvert, Andrew T.

2012-01-01

The cluster of glaciated stratovolcanoes called the Three Sisters—South Sister, Middle Sister, and North Sister—forms a spectacular 20-km-long reach along the crest of the Cascade Range in Oregon. The three eponymous stratocones, though contiguous and conventionally lumped sororally, could hardly display less family resemblance. North Sister (10,085 ft), a monotonously mafic edifice at least as old as 120 ka, is a glacially ravaged stratocone that consists of hundreds of thin rubbly lava flows and intercalated falls that dip radially and steeply; remnants of two thick lava flows cap its summit. Middle Sister (10,047 ft), an andesite-basalt-dacite cone built between 48 and 14 ka, is capped by a thick stack of radially dipping, dark-gray, thin mafic lava flows; asymmetrically glaciated, its nearly intact west flank contrasts sharply with its steep east face. Snow and ice-filled South Sister is a bimodal rhyolitic-intermediate edifice that was constructed between 50 ka and 2 ka; its crater (rim at 10,358 ft) was created between 30 and 22 ka, during the most recent of several explosive summit eruptions; the thin oxidized agglutinate that mantles its current crater rim protects a 150-m-thick pyroclastic sequence that helped fill a much larger crater. For each of the three, the eruptive volume is likely to have been in the range of 15 to 25 km³, but such estimates are fairly uncertain, owing to glacial erosion. The map area consists exclusively of Quaternary volcanic rocks and derivative surficial deposits. Although most of the area has been modified by glaciation, the volcanoes are young enough that the landforms remain largely constructional. Furthermore, twelve of the 145 eruptive units on the map are postglacial, younger than the deglaciation that was underway by about 17 ka. The most recent eruptions were of rhyolite near South Sister, about 2,000 years ago, and of mafic magma near McKenzie Pass, about 1,500 years ago. As observed by trailblazing volcanologist

Sultana et al., Afr J Tradit Complement Altern Med. (2016) 13(2):185 ...

African Journals Online (AJOL)

Shahid Mahboob

broken anaphase bridges formed due to chromosome rearrangements such as dicentric chromatids, intermingled ring chromosomes or union of sister chromatids‖ (Albertini et al., 2000; Bouraoui et al., 2014). The objective of this study was to assess the indirect effect of radiation in the hospital workers of radiotherapy from ...

Cohesive zone model for direct silicon wafer bonding

Science.gov (United States)

Kubair, D. V.; Spearing, S. M.

2007-05-01

Direct silicon wafer bonding and decohesion are simulated using a spectral scheme in conjunction with a rate-dependent cohesive model. The cohesive model is derived assuming the presence of a thin continuum liquid layer at the interface. Cohesive tractions due to the presence of a liquid meniscus always tend to reduce the separation distance between the wafers, thereby opposing debonding, while assisting the bonding process. In the absence of the rate-dependence effects the energy needed to bond a pair of wafers is equal to that needed to separate them. When rate-dependence is considered in the cohesive law, the experimentally observed asymmetry in the energetics can be explained. The derived cohesive model has the potential to form a bridge between experiments and a multiscale-modelling approach to understand the mechanics of wafer bonding.

40 CFR 79.65 - In vivo sister chromatid exchange assay.

Science.gov (United States)

2010-07-01

... PROGRAMS (CONTINUED) REGISTRATION OF FUELS AND FUEL ADDITIVES Testing Requirements for Registration § 79.65... appropriate concentration level, a pilot or trial study may be advisable. Initially, one concentration of the...., “Cytogenetic Studies of Mice Exposed to Styrene by Inhalation.”, Mutation Research, 280:35-43, 1992. (7) Wolff...

Abnormally banded chromosomal regions in doxorubicin-resistant B16-BL6 murine melanoma cells.

Science.gov (United States)

Slovak, M L; Hoeltge, G A; Ganapathi, R

1986-08-01

B16-BL6 murine melanoma cells were selected for cytogenetic evaluation during the stepwise development of increasing resistance in vitro to the antitumor antibiotic, doxorubicin (DOX). Karyotypic studies demonstrated extensive heteroploidy with both numerical and structural abnormalities which were not present in the parental DOX-sensitive B16-BL6 cells. Trypsin-Giemsa banding revealed the presence of several marker chromosomes containing abnormally banding regions (ABRs) in the 44-fold B16-BL6 DOX-resistant subline. These ABRs appeared to be more homogeneously staining at the higher DOX concentrations. Length measurements (ABR index) in seven banded metaphases indicated a direct correlation with increasing DOX concentration. When the DOX-resistant cells were grown in drug-free medium for 1 yr, the drug-resistant phenotype gradually declined in parallel with the level of resistance and the ABR index. DOX-induced cytogenetic damage examined by sister chromatid exchange methodology in parental B16-BL6 cells indicated a linear sister chromatid exchange:DOX dose-response relationship. However, after continuous treatment of parental B16-BL6 cells with DOX (0.01 microgram/ml) for 30 days, sister chromatid exchange scores were found to return to base-line values. The B16-BL6 resistant cells demonstrated a cross-resistant phenotype with N-trifluoroacetyladriamycin-14-valerate, actinomycin D, and the Vinca alkaloids but not with 1-beta-D-arabinofuranosylcytosine. The results suggest that ABR-containing chromosomes in DOX-resistant sublines may represent cytogenetic alterations of specific amplified genes involved in the expression of DOX resistance. Further studies are required to identify and define the possible gene products and to correlate their relationship to the cytotoxic action of doxorubicin.

INTANGIBLE ASSETS THROUGH THE COHESION POLICY

Directory of Open Access Journals (Sweden)

Popescu (Stingaciu Ana-Maria

2012-07-01

Full Text Available INTANGIBLE ASSETS THROUGH THE COHESION POLICY Roth Anne-Marie-Monika West University of Timisoara Faculty of Economics and Business Administration Popescu (Stingaciu Ana-Maria West University of Timisoara Faculty of Economics and Business Administration Intangible assets in general and intellectual capital in particular are important to both society and organizations. It can be a source of competitive advantage for business and stimulate innovation that leads to wealth generation. Technological revolutions, the rise of the knowledge-based economy and the networked society have all led to the same conclusion that intangibles and how they contribute to value creation have to be appreciated so that the appropriate decisions can be made to protect and enhance them. The Cohesion Policy represents the main EU measure to ensure a balanced and sustainable growth in Europe by promoting harmonious development and reducing the regional disparities. The general objective of the paper is to highlight the important role of the Cohesion Policy in the development of intangible assets. The objectives and the instruments of the Cohesion Policy are designed to support programs on regional development, economic change, enhanced competitiveness and territorial cooperation through the European Union, to develop human resources and employability. Keywords: intangible assets, intellectual capital, Cohesion policy, development; JEL Classification: O43, G32, D24, O34

Education and Social Cohesion: Higher Education

Science.gov (United States)

Moiseyenko, Olena

2005-01-01

Social cohesion is understood as the social networks and the norms of reciprocity and trustworthiness that arise from connections among individuals. When students attend higher education institutions, they go through a process of socialization, and it is vital to ensure that they acquire the core values that underpin the social cohesion. This…

20 CFR 725.225 - Determination of dependency; parent, brother, or sister.

Science.gov (United States)

2010-04-01

... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Determination of dependency; parent, brother, or sister. 725.225 Section 725.225 Employees' Benefits EMPLOYMENT STANDARDS ADMINISTRATION... Benefits) § 725.225 Determination of dependency; parent, brother, or sister. An individual who is the miner...

Andrographia paniculata a Miracle Herbs for cancer treatment: In ...

African Journals Online (AJOL)

It is extensively used as home remedy for various diseases in Indian traditional system ... Aim: In our present work, extracts of these ayurvedic plants were tested for their ... and anticarcinogenic properties against Aflatoxin B1 induced toxicity. ... (CA), sister chromatid exchanges (SCEs) and cell growth kinetics (RI) both in the ...

The Roberts syndrome/SC phocomelia spectrum--a case report of an adult with review of the literature.

Science.gov (United States)

Goh, Elaine Suk-Ying; Li, Chumei; Horsburgh, Sheri; Kasai, Yumi; Kolomietz, Elena; Morel, Chantal France

2010-02-01

Roberts syndrome (RBS) (OMIM #268300) is a rare autosomal recessive disorder characterized by tetraphocomelia (symmetrical limb reduction), craniofacial anomalies, growth retardation, mental retardation, cardiac and renal abnormalities. The syndrome is caused by mutations in the ESCO2 (establishment of cohesion 1 homolog 2) (Entrez 609353) gene, which is located at 8p21.1, and encodes a protein essential in establishing sister chromatid cohesion during S phase. SC phocomelia (SC) (OMIM #269000), has less severe symmetric limb reduction, flexion contractures of various joints, minor facial anomalies, growth retardation and occasionally, mental retardation. These two syndromes can be considered part of a spectrum, with RBS at the most severe range in which severely affected infants may be stillborn or die in the post-natal period, while individuals with SC phocomelia represent the milder end of the spectrum and typically survive to adulthood. In both presentations, karyotype investigations characteristically reveal premature centromere separation (PCS), otherwise known as heterochromatin repulsion or puffing. There is little literature about the follow-up of adults with the spectrum of RBS/SC phocomelia or their recommended management. We report on an adult presentation of RBS/SC phocomelia spectrum disorder with a history of major cardiac malformation in childhood, normal limbs on physical examination, mild facial anomalies, mild learning difficulties, and PCS. Molecular studies of ESCO2 have confirmed the diagnosis. A literature review, focussing on adult manifestations of this condition and a discussion of follow-up guidelines are presented. Copyright 2010 Wiley-Liss, Inc.

Kinetics of chromatid aberrations in G2 ataxia-telangiectasia cells exposed to X-rays and ara A

International Nuclear Information System (INIS)

Mozdarani, Hossein; Bryant, P.E.

1989-01-01

The cytogenetic effects of X-rays alone or in combination with 9-β-D-arabinofuranosyladenine (ara A) were studied in an immortalized fibroblastic line of ataxia-telangiectasia (A-T) cells. It is postulated that the kinetics of disappearance (rejoining) of chromatid deletions with postirradiation incubation time reflects the underlying repair of dsb, and is inhibited by ara A. The rejoining kinetics for deletions in A-T was similar to that found in a previous study of normal human fibroblasts (Mozdarani and Bryant 1987). The number of deletions in X-irradiated A-T cells at 1.5 h before fixation was found to be higher by a factor of approximately 2 than that found previously in normals, indicating that in A-T a higher rate of conversion of dsb into chromatid deletions occurs. The frequency of exchanges induced in G2 A-T cells was similarly enhanced but, unlike the situation in normal cells, ara A was found to cause only a slight increase in this frequency. (author)

Psychobiological Assessment and Enhancement of Team Cohesion and Psychological Resilience in ROTC Cadets Using a Virtual-Reality Team Cohesion Test

Science.gov (United States)

2016-06-01

Using a Virtual - Reality Team Cohesion Test PRINCIPAL INVESTIGATOR: Josh Woolley MD/PhD CONTRACTING ORGANIZATION: NORTHERN CALIFORNIA INSTITUTE SAN...Team Cohesion and Psychological Resilience in ROTC Cadets Using a Virtual - Reality Team Cohesion Test 5b. GRANT NUMBER W81XWH-15-1-0042 5c. PROGRAM...targets while flying a virtual air vehicle. No individual has access to all the necessary information or controls, so operating as a team is crucial

[Florence Nightingale and charity sisters: revisiting the history].

Science.gov (United States)

Padilha, Maria Itayra Coelho de Souza; Mancia, Joel Rolim

2005-01-01

This study presents an historical analysis on the links between the nursing practice and the influence received from various religious orders/associations along the times, especially from Saint Vincent Paul's charity sisters. The professional nursing which was pioneered by Florence Nightingale in the XlXth century, was directly influenced by the teachings of love and fraternity. In addition, other contributions from the religious orders/associations were the concepts of altruism, valorization of an adequate environment for the care of patients, and the division of work in nursing. The study shows the influence of Charity Sisters on Florence Nightingale.

Natural disasters and indicators of social cohesion.

Science.gov (United States)

Calo-Blanco, Aitor; Kovářík, Jaromír; Mengel, Friederike; Romero, José Gabriel

2017-01-01

Do adversarial environmental conditions create social cohesion? We provide new answers to this question by exploiting spatial and temporal variation in exposure to earthquakes across Chile. Using a variety of methods and controlling for a number of socio-economic variables, we find that exposure to earthquakes has a positive effect on several indicators of social cohesion. Social cohesion increases after a big earthquake and slowly erodes in periods where environmental conditions are less adverse. Our results contribute to the current debate on whether and how environmental conditions shape formal and informal institutions.

Chromosome fragility in Freemartin cattle

Directory of Open Access Journals (Sweden)

V. Barbieri

2010-04-01

Full Text Available The aim of the present study was to verify chromosome fragility in freemartin cattle using chromosome aberration (CA and sister chromatid exchange (SCE tests. A total of eighteen co-twins were investigated. Fourteen animals were identified as cytogenetically chimeric (2n=60, XX/XY while 4 were classified as normal. Freemartin cattle showed a higher percentage of aneuploid cells (18.64% and highly significant statistical differences (P < 0.001 in mean values of gaps (4.53 ± 2.05, chromatid breaks (0.26 ± 0.51, and significant statistical differences (P < 0.005 in mean values of chromosome breaks (0.12 ± 0.43 when compared to 10 control animals from single births (aneuploid cells, 11.20%; gaps, 2.01 ± 1.42; chromatid breaks, 0.05 ± 0.22; chromosome breaks, 0.02 ± 0.14.

Cohesion energetics of carbon allotropes: Quantum Monte Carlo study

Energy Technology Data Exchange (ETDEWEB)

Shin, Hyeondeok; Kang, Sinabro; Koo, Jahyun; Lee, Hoonkyung; Kwon, Yongkyung, E-mail: ykwon@konkuk.ac.kr [Division of Quantum Phases and Devices, School of Physics, Konkuk University, Seoul 143-701 (Korea, Republic of); Kim, Jeongnim, E-mail: jnkim@ornl.gov [Materials Science and Technology Division and Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2014-03-21

We have performed quantum Monte Carlo calculations to study the cohesion energetics of carbon allotropes, including sp{sup 3}-bonded diamond, sp{sup 2}-bonded graphene, sp–sp{sup 2} hybridized graphynes, and sp-bonded carbyne. The computed cohesive energies of diamond and graphene are found to be in excellent agreement with the corresponding values determined experimentally for diamond and graphite, respectively, when the zero-point energies, along with the interlayer binding in the case of graphite, are included. We have also found that the cohesive energy of graphyne decreases systematically as the ratio of sp-bonded carbon atoms increases. The cohesive energy of γ-graphyne, the most energetically stable graphyne, turns out to be 6.766(6) eV/atom, which is smaller than that of graphene by 0.698(12) eV/atom. Experimental difficulty in synthesizing graphynes could be explained by their significantly smaller cohesive energies. Finally, we conclude that the cohesive energy of a newly proposed graphyne can be accurately estimated with the carbon–carbon bond energies determined from the cohesive energies of graphene and three different graphynes considered here.

Cohesion Energetics of Carbon Allotropes: Quantum Monte Carlo Study

Energy Technology Data Exchange (ETDEWEB)

Shin, Hyeondeok [Konkuk University, South Korea; Kang, Sinabro [Konkuk University, South Korea; Koo, Jahyun [Konkuk University, South Korea; Lee, Hoonkyung [Konkuk University, South Korea; Kim, Jeongnim [ORNL; Kwon, Yongkyung [Konkuk University, South Korea

2014-01-01

We have performed quantum Monte Carlo calculations to study the cohesion energetics of carbon allotropes, including sp3-bonded diamond, sp2-bonded graphene, sp-sp2 hybridized graphynes, and sp-bonded carbyne. The comput- ed cohesive energies of diamond and graphene are found to be in excellent agreement with the corresponding values de- termined experimentally for diamond and graphite, respectively, when the zero-point energies, along with the interlayer binding in the case of graphite, are included. We have also found that the cohesive energy of graphyne decreases system- atically as the ratio of sp-bonded carbon atoms increases. The cohesive energy of -graphyne, the most energetically- stable graphyne, turns out to be 6.766(6) eV/atom, which is smaller than that of graphene by 0.698(12) eV/atom. Experi- mental difficulty in synthesizing graphynes could be explained by their significantly smaller cohesive energies. Finally we conclude that the cohesive energy of a newly-proposed two-dimensional carbon network can be accurately estimated with the carbon-carbon bond energies determined from the cohesive energies of graphene and three different graphynes.

Clouston′s Disease in Three Sisters

Directory of Open Access Journals (Sweden)

Jayakar Thomas

1988-01-01

Full Text Available In a family of four children, all females, three sisters presented with Clouston′s disease or hidrotic ectodermal dysplasia. The case is reported for the rarity of presentation in a single generation with no history of other family members affected.

Territorial cohesion post - 2013 : To whomsoever it may concern

NARCIS (Netherlands)

Faludi, A.K.F.

2010-01-01

Conceived as a motion for resolution, the paper considers territorial cohesion now being on the statute book, the Green Paper on Territorial Cohesion, Barca making the case for integrated, place-based strategies, the EU Strategy for the Baltic Sea Region and the future of Cohesion policy. The

Written cohesion in children with and without language learning disabilities.

Science.gov (United States)

Koutsoftas, Anthony D; Petersen, Victoria

2017-09-01

Cohesion refers to the linguistic elements of discourse that contribute to its continuity and is an important element to consider as part of written language intervention, especially in children with language learning disabilities (LLD). There is substantial evidence that children with LLD perform more poorly than typically developing (TD) peers on measures of cohesion in spoken language and on written transcription measures; however, there is far less research comparing groups on cohesion as a measure of written language across genres. The current study addresses this gap through the following two aims. First, to describe and compare cohesion in narrative and expository writing samples of children with and without language learning disabilities. Second, to relate measures of cohesion to written transcription and translation measures, oral language, and writing quality. Fifty intermediate-grade children produced one narrative and one expository writing sample from which measures of written cohesion were obtained. These included the frequency, adequacy and complexity of referential and conjunctive ties. Expository samples resulted in more complex cohesive ties and children with TD used more complex ties than peers with LLD. Different relationships among cohesion measures and writing were observed for narrative verse expository samples. Findings from this study demonstrate cohesion as a discourse-level measure of written transcription and how the use of cohesion can vary by genre and group (LLD, TD). Clinical implications for assessment, intervention, and future research are provided. © 2016 Royal College of Speech and Language Therapists.

The association between status and cohesion in sport teams.

Science.gov (United States)

Jacob, C S; Carron, A V

1998-02-01

The main objective of this study was to establish the relationship between perceptions of status attributes and cohesion and status ranking and cohesion. A secondary aim was to determine whether age (operationalized by scholastic levels) or culture serves as a moderator in the relationship between either status attributes or status ranking and cohesion. Another secondary aim was to determine if differences are present in the importance attached by athletes to status attributes. Canadian and Indian athletes were tested. Although perceptions of the importance of status attributes and cohesiveness were related, the effect size was small (Green, 1991); perceptions of status ranking and cohesiveness were not related. Neither scholastic level nor culture served as a moderator in the association between either status attributes or status rank and cohesion. The importance that athletes attach to status attributes is similar between scholastic levels and across cultures. The results are discussed in terms of the role of status in sport teams.

Why are Rich Countries more Politically Cohesive?

DEFF Research Database (Denmark)

Dalgaard, Carl-Johan Lars; Olsson, Ola

of other groups in society. If the gains from specialization become sufficiently large, however, a market economy will emerge. From being essentially non-cohesive under self-sufficiency, the political decision making process becomes cohesive in the market economy, as the welfare of individuals...

Friel and his "sisters"

Directory of Open Access Journals (Sweden)

Nicholas Grene

2010-11-01

Full Text Available This essay, occasioned by a revival of Brian Friel's version of Chekhov's Three Sisters at the Abbey Theatre in 2008, considers the circumstances surrounding its first production by the Field Day Theatre Company in 1981, and the motivation behind the decision to translate Chekhov's text into a specifically Irish dialect of English. It also analyses how Friel's plays since that date, notably the award-winning Dancing at Lughnasa (1990, have changed our perspective on the play.

Justice and Social Cohesion: Some conservative perspectives

DEFF Research Database (Denmark)

Pedersen, Søren Hviid

2011-01-01

In the wake of recent debates on multiculturalism and value-pluralism, the pressing questions now focuses on whether social cohesion and the notion of justice are sustainable and can be upheld, at least from a European perspective. There are many theoretical and academic responses, mainly from...... liberals, on how to accommodate the different demands of various ethnic and religious groups and at the same time sustain a minimum of social cohesion and justice. One voice is missing and that is a conservative perspective. The purpose of this paper is to formulate a modern conservative analysis...... of this problem. The argument presented in this paper will, first, take its point of departure from David Hume’s notion of sympathy and how this makes social cohesion possible. Second, it will be argued that social cohesion is a prerequisite for the existence of justice, and therefore justice is a derivative...

4. National Congress on Genetics. Memoirs

International Nuclear Information System (INIS)

1993-01-01

According to INIS coverage were analyzed four free works on Life and Environmental Sciences presented during the Congress which are treating over the effects of external irradiation on animals. Between the main aspects are the sister chromatid exchange, spermatogonia, somatic cells, genotoxicity, DNA, chlorophyll, gamma radiation, bone marrow cells and radiation injuries

Andrographia paniculata a Miracle Herbs for cancer treatment: In vivo and in vitro studies against Aflatoxin B1 Toxicity

Directory of Open Access Journals (Sweden)

Md. Sultan Ahmad

2014-04-01

Conclusion: In conclusion A. paniculata extracts significantly reduced the number of aberrant cells and frequencies of aberration per cell at each concentration and duration of exposure in vivo; similarly it reduced chromosomal aberrations and sister chromatid exchanges and replication index was enhanced in vitro that was statistically significant at <0.05 level.

Molecular Intercalation and Cohesion of Organic Bulk Heterojunction Photovoltaic Devices

KAUST Repository

Bruner, Christopher; Miller, Nichole C.; McGehee, Michael D.; Dauskardt, Reinhold H.

2013-01-01

The phase separated bulk heterojunction (BHJ) layer in BHJ polymer:fullerene organic photovoltaic devices (OPV) are mechanically weak with low values of cohesion. Improved cohesion is important for OPV device thermomechanical reliability. BHJ devices are investigated and how fullerene intercalation within the active layer affects cohesive properties in the BHJ is shown. The intercalation of fullerenes between the side chains of the polymers poly(3,3″′-didocecyl quaterthiophene) (PQT-12) and poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT) is shown to enhance BHJ layer cohesion. Cohesion values range from ≈1 to 5 J m -2, depending on the polymer:fullerene blend, processing conditions, and composition. Devices with non-intercalated BHJ layers are found to have significantly reduced values of cohesion. The resulting device power conversion efficiencies (PCE) are also investigated and correlated with the device cohesion. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Molecular Intercalation and Cohesion of Organic Bulk Heterojunction Photovoltaic Devices

KAUST Repository

Bruner, Christopher

2013-01-17

The phase separated bulk heterojunction (BHJ) layer in BHJ polymer:fullerene organic photovoltaic devices (OPV) are mechanically weak with low values of cohesion. Improved cohesion is important for OPV device thermomechanical reliability. BHJ devices are investigated and how fullerene intercalation within the active layer affects cohesive properties in the BHJ is shown. The intercalation of fullerenes between the side chains of the polymers poly(3,3″′-didocecyl quaterthiophene) (PQT-12) and poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (pBTTT) is shown to enhance BHJ layer cohesion. Cohesion values range from ≈1 to 5 J m -2, depending on the polymer:fullerene blend, processing conditions, and composition. Devices with non-intercalated BHJ layers are found to have significantly reduced values of cohesion. The resulting device power conversion efficiencies (PCE) are also investigated and correlated with the device cohesion. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cohesion as interaction in ELF spoken discourse

Directory of Open Access Journals (Sweden)

T. Christiansen

2013-10-01

Full Text Available Hitherto, most research into cohesion has concentrated on texts (usually written only in standard Native Speaker English – e.g. Halliday and Hasan (1976. By contrast, following on the work in anaphora of such scholars as Reinhart (1983 and Cornish (1999, Christiansen (2011 describes cohesion as an interac­tive process focusing on the link between text cohesion and discourse coherence. Such a consideration of cohesion from the perspective of discourse (i.e. the process of which text is the product -- Widdowson 1984, p. 100 is especially relevant within a lingua franca context as the issue of different variations of ELF and inter-cultural concerns (Guido 2008 add extra dimensions to the complex multi-code interaction. In this case study, six extracts of transcripts (approximately 1000 words each, taken from the VOICE corpus (2011 of conference question and answer sessions (spoken interaction set in multicultural university con­texts are analysed in depth by means of a qualitative method.

Cell-stage-specific enhancement by caffeine of the frequency of chromatid aberrations induced by X-rays in neutral ganglia of Drosophila melanogaster

International Nuclear Information System (INIS)

De Marco, A.; Polani, S.

1981-01-01

Caffeine (10 -2 M) induced a high level of chromatid aberrations in neural ganglia of third-instar larvae of Drosophila melanogaster only when it was added to cells in late G 2 and mitotic prophase. No aberrations were observed after treatment in late S-middle G 2 or C-mitosis. We observed that, in these stages, caffeine strongly increased X-ray-induced damage (500 R). This potentiation was quantitatively similar. But it involved all types of aberration after treatment in C-mitosis, and essentially isochromatid deletions and chromatid exhanges after treatment in S-G 2 . Some hypotheses are put forth to explain the possible mechanism of action of caffeine in the potentiation of X-ray-induced damage. (orig.)

Sisters Hope - Protected by the Fiction

DEFF Research Database (Denmark)

Lawaetz, Anna; Hallberg, Gry Worre

2011-01-01

In this article we will introduce the fictional and art-pedagogical universe of Sisters Hope and describe how it in different ways transcends into contexts beyond the art world and thus functions as a tool to democratize the aesthetic dimension and mode of being within high schools, academia...

Neighborhood cohesion, neighborhood disorder, and cardiometabolic risk.

Science.gov (United States)

Robinette, Jennifer W; Charles, Susan T; Gruenewald, Tara L

2018-02-01

Perceptions of neighborhood disorder (trash, vandalism) and cohesion (neighbors trust one another) are related to residents' health. Affective and behavioral factors have been identified, but often in studies using geographically select samples. We use a nationally representative sample (n = 9032) of United States older adults from the Health and Retirement Study to examine cardiometabolic risk in relation to perceptions of neighborhood cohesion and disorder. Lower cohesion is significantly related to greater cardiometabolic risk in 2006/2008 and predicts greater risk four years later (2010/2012). The longitudinal relation is partially accounted for by anxiety and physical activity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Interdependence of the rad50 hook and globular domain functions.

Science.gov (United States)

Hohl, Marcel; Kochańczyk, Tomasz; Tous, Cristina; Aguilera, Andrés; Krężel, Artur; Petrini, John H J

2015-02-05

Rad50 contains a conserved Zn(2+) coordination domain (the Rad50 hook) that functions as a homodimerization interface. Hook ablation phenocopies Rad50 deficiency in all respects. Here, we focused on rad50 mutations flanking the Zn(2+)-coordinating hook cysteines. These mutants impaired hook-mediated dimerization, but recombination between sister chromatids was largely unaffected. This may reflect that cohesin-mediated sister chromatid interactions are sufficient for double-strand break repair. However, Mre11 complex functions specified by the globular domain, including Tel1 (ATM) activation, nonhomologous end joining, and DNA double-strand break end resection were affected, suggesting that dimerization exerts a broad influence on Mre11 complex function. These phenotypes were suppressed by mutations within the coiled-coil and globular ATPase domains, suggesting a model in which conformational changes in the hook and globular domains are transmitted via the extended coils of Rad50. We propose that transmission of spatial information in this manner underlies the regulation of Mre11 complex functions. Copyright © 2015 Elsevier Inc. All rights reserved.

Loss of heterozygosity in yeast can occur by ultraviolet irradiation during the S phase of the cell cycle

Energy Technology Data Exchange (ETDEWEB)

Daigaku, Yasukazu [Graduate School of Life Sciences, Tohoku University, Sendai 980-8577 (Japan); Mashiko, Satsuki [Graduate School of Life Sciences, Tohoku University, Sendai 980-8577 (Japan); Mishiba, Keiichiro [Iwate Biotechnology Research Center, Kitakami, Iwate 024-0003 (Japan); Yamamura, Saburo [Iwate Biotechnology Research Center, Kitakami, Iwate 024-0003 (Japan); Ui, Ayako [Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578 (Japan); Enomoto, Takemi [Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai 980-8578 (Japan); Yamamoto, Kazuo [Graduate School of Life Sciences, Tohoku University, Sendai 980-8577 (Japan)]. E-mail: yamamot@mail.tains.tohoku.ac.jp

2006-08-30

A CAN1/can1{delta} heterozygous allele that determines loss of heterozygosity (LOH) was used to study recombination in Saccharomyces cerevisiae cells exposed to ultraviolet (UV) light at different points in the cell cycle. With this allele, recombination events can be detected as canavanine-resistant mutations after exposure of cells to UV radiation, since a significant fraction of LOH events appear to arise from recombination between homologous chromosomes. The radiation caused a higher level of LOH in cells that were in the S phase of the cell cycle relative to either cells at other points in the cell cycle or unsynchronized cells. In contrast, the inactivation of nucleotide excision repair abolished the cell cycle-specific induction by UV of LOH. We hypothesize that DNA lesions, if not repaired, were converted into double-strand breaks during stalled replication and these breaks could be repaired through recombination using a non-sister chromatid and probably also the sister chromatid. We argue that LOH may be an outcome used by yeast cells to recover from stalled replication at a lesion.

Loss of heterozygosity in yeast can occur by ultraviolet irradiation during the S phase of the cell cycle.

Science.gov (United States)

Daigaku, Yasukazu; Mashiko, Satsuki; Mishiba, Keiichiro; Yamamura, Saburo; Ui, Ayako; Enomoto, Takemi; Yamamoto, Kazuo

2006-08-30

A CAN1/can1Delta heterozygous allele that determines loss of heterozygosity (LOH) was used to study recombination in Saccharomyces cerevisiae cells exposed to ultraviolet (UV) light at different points in the cell cycle. With this allele, recombination events can be detected as canavanine-resistant mutations after exposure of cells to UV radiation, since a significant fraction of LOH events appear to arise from recombination between homologous chromosomes. The radiation caused a higher level of LOH in cells that were in the S phase of the cell cycle relative to either cells at other points in the cell cycle or unsynchronized cells. In contrast, the inactivation of nucleotide excision repair abolished the cell cycle-specific induction by UV of LOH. We hypothesize that DNA lesions, if not repaired, were converted into double-strand breaks during stalled replication and these breaks could be repaired through recombination using a non-sister chromatid and probably also the sister chromatid. We argue that LOH may be an outcome used by yeast cells to recover from stalled replication at a lesion.

Identification of a Sgo2-Dependent but Mad2-Independent Pathway Controlling Anaphase Onset in Fission Yeast

Directory of Open Access Journals (Sweden)

John C. Meadows

2017-02-01

Full Text Available The onset of anaphase is triggered by activation of the anaphase-promoting complex/cyclosome (APC/C following silencing of the spindle assembly checkpoint (SAC. APC/C triggers ubiquitination of Securin and Cyclin B, which leads to loss of sister chromatid cohesion and inactivation of Cyclin B/Cdk1, respectively. This promotes relocalization of Aurora B kinase and other components of the chromosome passenger complex (CPC from centromeres to the spindle midzone. In fission yeast, this is mediated by Clp1 phosphatase-dependent interaction of CPC with Klp9/MKLP2 (kinesin-6. When this interaction is disrupted, kinetochores bi-orient normally, but APC/C activation is delayed via a mechanism that requires Sgo2 and some (Bub1, Mph1/Mps1, and Mad3, but not all (Mad1 and Mad2, components of the SAC and the first, but not second, lysine, glutamic acid, glutamine (KEN box in Mad3. These data indicate that interaction of CPC with Klp9 terminates a Sgo2-dependent, but Mad2-independent, APC/C-inhibitory pathway that is distinct from the canonical SAC.

Estimating cohesion in small groups using audio-visual nonverbal behavior

NARCIS (Netherlands)

Hung, H.; Gatica-Perez, D.

2010-01-01

Cohesiveness in teams is an essential part of ensuring the smooth running of task-oriented groups. Research in social psychology and management has shown that good cohesion in groups can be correlated with team effectiveness or productivity, so automatically estimating group cohesion for team

[Family cohesion associated with oral health, socioeconomic factors and health behavior].

Science.gov (United States)

Ferreira, Luale Leão; Brandão, Gustavo Antônio Martins; Garcia, Gustavo; Batista, Marília Jesus; Costa, Ludmila da Silva Tavares; Ambrosano, Gláucia Maria Bovi; Possobon, Rosana de Fátima

2013-08-01

Overall health surveys have related family cohesion to socio-economic status and behavioral factors. The scope of this study was to investigate the association between family cohesion and socio-economic, behavioral and oral health factors. This was a, cross-sectional study with two-stage cluster sampling. The random sample consisted of 524 adolescents attending public schools in the city of Piracicaba-SP. Variables were evaluated by self-applied questionnaires and caries and periodontal disease were assessed by DMF-T and CPI indices. The adolescent's perception of family cohesion was assessed using the family adaptability and cohesion scale. Univariate and multinomial logistic regression shows that adolescents with low family cohesion were more likely than those with medium family cohesion to have low income (OR 2,28 95% CI 1,14- 4,55), presence of caries (OR 2,23 95% CI 1,21-4,09), less than two daily brushings (OR 1,91 95% CI 1,03-3,54). Adolescents with high family cohesion were more likely than those with medium family cohesion to have high income and protective behavior against the habit of smoking. Thus, the data shows that adolescent perception of family cohesion was associated with behavioral, socio-economic and oral health variables, indicating the importance of an integral approach to patient health.

An examination of the cohesion-performance relationship in university hockey teams.

Science.gov (United States)

Slater, M R; Sewell, D F

1994-10-01

The objective of this study was to assess, using the Group Environment Questionnaire, whether team cohesion in university-level field hockey was a cause for, or an effect of, successful performance. A quasi-experimental longitudinal design with cross-lagged correlational analysis was adopted and measures of cohesion and performance were taken midway and later in the season. The results of the synchronous correlations showed a positive relationship (with good stationarity) between team cohesion and performance outcome. Although non-significant cross-lagged differentials indicated a circular relationship, the magnitudes of both the cross-lagged correlations and the partial correlations, together with multiple-regression analyses, revealed that the stronger flow was from cohesion to performance. The socially oriented aspects of cohesion, in particular, had significant associations with performance. The results imply that cohesion-performance relationships should be examined within a circular model, in which cohesion and performance are interdependent.

Cohesion and Hierarchy in Physically Abusive Families

Directory of Open Access Journals (Sweden)

Clarissa De Antoni

2009-06-01

Full Text Available This paper investigates cohesion (emotional bonding and hierarchy (powerstructure in families with abuse against their children. Twenty low-incomefamilies participated. Father, mother and child’s perspective of family relations(cohesion and hierarchy were evaluated by the Family System Test(FAST. The relationship between father-child, mother-child, couple, andamong siblings were evaluated at typical and conflictive situations. Resultsshow a significance regarding to cohesion in typical and conflictive situationfor father-child and mother-child dyads in all perspectives (by father, mother,and child. There is no significant differences regarding to hierarchy. Theseresults suggest that the families see the intrafamilial violence as a constant,since they cannot differentiate between both situations.

The effect of biological cohesion on current ripple development

Science.gov (United States)

Malarkey, Jonathan; Baas, Jaco H.; Hope, Julie

2014-05-01

Results are presented from laboratory experiments examining the role of biological cohesion, associated with Extra Polymeric Substances, on the development of current ripples. The results demonstrate the importance of biological cohesion compared to the effect of physical cohesion associated with clays in an otherwise sandy bed. FURTHER INFORMATION In fluvial and marine environments sediment transport is mainly dependent on the nature of the bed surface (rippled or flat) and the nature of cohesion in the bed. Cohesion can be either physical, as a result of the presence of clays, or biological as a result of the presence of organisms. In the case of the latter, biological cohesion occurs as a result of the presence of Extra Polymeric Substances (EPS) secreted by microorganisms. While it is known that EPS can dramatically increase the threshold of motion (Grant and Gust, 1987), comparatively little is known about the effect of EPS on ripple formation and development. The experiments described here seek to fill this gap. They also allow the effect of biological cohesion to be compared with that of physical cohesion from previous experiments (Baas et al., 2013). The experiments, which were conducted in a 10m flume at Bangor University, involved a current over a bed made of fine sand, with a median diameter of 0.148mm, and various amounts of xanthan gum, a proxy for naturally occurring EPS (Vardy et al., 2007). The hydrodynamic experimental conditions were matched very closely to those of Baas et al. (2013). The ripple dimensions were recorded through the glass side wall of the tank using time lapse photography. In the physical cohesion experiments of Baas et al. (2013) for clay contents up to 12%, the clay was very quickly winnowed out of the bed, leaving essentially clay-free ripples that developed at more or less the same rate as clean sand ripples. The resulting equilibrium ripples were essentially the same length as the clean sand ripples but reduced in height. By

Further environmental factors causing variations of SCE frequencies

International Nuclear Information System (INIS)

Tuschl, H.; Kovac, R.; Wottawa, A.

1986-12-01

The frequencies of spontaneously occurring sister chromatid exchanges (=SCE) were determined in control persons, persons exposed to very low doses of ionizing radiation and employees of a rubber factory. Besides smoking habits and the usage of oral contraceptives, background ultraviolet (=UV) radiation seems to exert the most pronounced effect on SCE levels in control persons. (Author)

Cancer predictive value of cytogenetic markers used in occupational health surveillance programs

DEFF Research Database (Denmark)

Hagmar, L; Bonassi, S; Strömberg, U

1998-01-01

It has not previously been clear whether cytogenetic biomarkers in healthy subjects will predict cancer. Earlier analyses of a Nordic and an Italian cohort indicated predictivity for chromosomal aberrations (CAS) but not for sister chromatid exchanges (SCES). A pooled analysis of the updated......, occupational exposures and smoking, will be assessed in a case-referent study within the study base....

Determination of mode-I cohesive strength for interfaces

DEFF Research Database (Denmark)

Jørgensen, J. B.; Thouless, M. D.; Sørensen, Bent F.

2016-01-01

The cohesive strength is one of the governing parameters controlling crack deflection at interfaces, but measuring its magnitude is challenging. In this paper, we demonstrate a novel approach to determine the mode-I cohesive strength of an interface by using a 4-point single-edge-notch beam...... in response to this stress, before the main crack starts to grow. Observations using 2D digital-image correlation showed that an ''apparent" strain across the interface initially increases linearly with the applied load, but becomes nonlinear upon the initiation of the interface crack. The cohesive strength...

Barossa Night: cohesion in the British Army officer corps.

Science.gov (United States)

Bury, Patrick

2017-06-01

Contrasting the classical explanation of military group cohesion as sustained by interpersonal bonds, recent scholars have highlighted the importance of ritualized communication, training and drills in explaining effective military performance in professional armies. While this has offered a welcome addition to the cohesion literature and a novel micro-sociological method of examining cohesion, its primary evidential base has been combat groups. Indeed, despite their prominent role in directing operations over the past decade, the British Army's officer corps has received relatively little attention from sociologists during this period. No attempt has been made to explain cohesion in the officer corps. Using a similar method to recent cohesion scholars, this paper seeks to address this imbalance by undertaking a micro-sociology of one ritual in particular: 'Barossa Night' in the Royal Irish Regiment. Firstly, it draws on the work of Durkheim to examine how cohesion amongst the officer corps is created and sustained through a dense array of practises during formal social rituals. It provides evidence that the use of rituals highlights that social solidarity is central to understanding officer cohesion. Secondly, following Hockey's work on how private soldiers negotiate order, the paper shows how this solidarity in the officer corps is based on a degree of negotiated order and the need to release organizational tensions inherent in a strictly hierarchical rank structure. It highlights how the awarding of gallantry medals can threaten this negotiated order and fuel deviancy. In examining this behaviour, the paper shows that even amongst an officer class traditionally viewed as the elite upholders of organizational discipline, the negotiation of rank and hierarchy can be fluid. How deviant behaviour is later accepted and normalized by senior officers indicates that negotiated order is as important to understanding cohesion in the British Army's officer corps as it is

Essential roles of BCCIP in mouse embryonic development and structural stability of chromosomes.

Directory of Open Access Journals (Sweden)

Huimei Lu

2011-09-01

Full Text Available BCCIP is a BRCA2- and CDKN1A(p21-interacting protein that has been implicated in the maintenance of genomic integrity. To understand the in vivo functions of BCCIP, we generated a conditional BCCIP knockdown transgenic mouse model using Cre-LoxP mediated RNA interference. The BCCIP knockdown embryos displayed impaired cellular proliferation and apoptosis at day E7.5. Consistent with these results, the in vitro proliferation of blastocysts and mouse embryonic fibroblasts (MEFs of BCCIP knockdown mice were impaired considerably. The BCCIP deficient mouse embryos die before E11.5 day. Deletion of the p53 gene could not rescue the embryonic lethality due to BCCIP deficiency, but partially rescues the growth delay of mouse embryonic fibroblasts in vitro. To further understand the cause of development and proliferation defects in BCCIP-deficient mice, MEFs were subjected to chromosome stability analysis. The BCCIP-deficient MEFs displayed significant spontaneous chromosome structural alterations associated with replication stress, including a 3.5-fold induction of chromatid breaks. Remarkably, the BCCIP-deficient MEFs had a ∼20-fold increase in sister chromatid union (SCU, yet the induction of sister chromatid exchanges (SCE was modestly at 1.5 fold. SCU is a unique type of chromatid aberration that may give rise to chromatin bridges between daughter nuclei in anaphase. In addition, the BCCIP-deficient MEFs have reduced repair of irradiation-induced DNA damage and reductions of Rad51 protein and nuclear foci. Our data suggest a unique function of BCCIP, not only in repair of DNA damage, but also in resolving stalled replication forks and prevention of replication stress. In addition, BCCIP deficiency causes excessive spontaneous chromatin bridges via the formation of SCU, which can subsequently impair chromosome segregations in mitosis and cell division.

INTERACTIVE EFFECTS OF TEAM COHESION ON PERCEIVED EFFICACY IN SEMI-PROFESSIONAL SPORT

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Francisco Miguel Leo Marcos

2010-06-01

Full Text Available The present study examined the relationships among cohesion, self-efficacy, coaches' perceptions of their players' efficacy at the individual level and athletes' perceptions of their teammates' efficacy. Participants (n = 76 recruited from four semi- professional soccer and basketball teams completed cohesiveness and efficacy questionnaires who. Data were analyzed through a correlational methodology. Results indicated significant correlations between self-efficacy and task cohesion and social cohesion. Regression analysis results suggest task cohesion positively related to coaches and teammate´s perception of efficacy. These results have implications for practitioners in terms of the importance of team building to enhance team cohesion and feelings of efficacy

Grain-resolving simulations of settling cohesive sediment

Science.gov (United States)

Vowinckel, Bernhard; Whithers, Jade; Meiburg, Eckart; Luzzatto-Fegiz, Paolo

2017-11-01

Cohesive sediment is ubiquitous in natural environments such as rivers, lakes and coastal ecosystems. For this type of sediment, we can no longer ignore the short-range attractive forces that result in flocculation of aggregates much larger than the individual grain size. Hence, understanding the complex dynamics of the interplay between flocculated sediment and the ambient fluid is of prime interest for managing aquatic environments, although a comprehensive understanding of these phenomena is still lacking. In the present study, we address this issue by carrying out grain-resolved simulations of cohesive particles settling under gravity using the Immersed Boundary Method. We present a computational model formulation to accurately resolve the process of flocculation. The cohesive model is then applied to a complex test case. A randomly distributed ensemble of 1261 polydisperse particles is released in a tank of quiescent fluid. Subsequently, particles start to settle, thereby replacing fluid at the bottom of the tank, which induces a counter flow opposing the settling direction. This mechanism will be compared to experimental studies from the literature, as well as to the non-cohesive counterpart to assessthe impact of flocculation on sedimentation.

Fanconi anaemia proteins are associated with sister chromatid bridging in mitosis

DEFF Research Database (Denmark)

Ying, Songmin; Hickson, Ian D

2011-01-01

exist in man where a breakdown in genome maintenance is associated with cancer predisposition. Amongst these are Bloom's syndrome (BS) and Fanconi anaemia (FA). The BS and FA gene products co-operate in the repair of damaged DNA. In this review, we focus on interactions between BS and FA proteins...

Cohesion Policy Contributing to Territorial Cohesion – Future Scenarios

Directory of Open Access Journals (Sweden)

Andreas Faludi

2011-09-01

Full Text Available The Barca Report advocates for developmental policies to be ‘place-based’: integrated as far as they affect ‘places’. The debate on territorial cohesion is equally concerned with integrating relevant policies and actions. This requires well-established democratic institutions and adequate responses to the demands of technical systems and of markets. Following Lisbeth Hooghe and Gary Marks, the respective arrangements are described as Governance Type I and Type II. All levels of government, including that of the EU, partake in both types, but relations between them are problematic, particularly in the context of Europe 2020: Will this EU strategy be mainly a matter for Directorate-Generals and their various clients pursuing their policies (Governance Type II, or will Cohesion policy, with its more integrated and decentralised approach, involving many levels of government and stakeholders (Governance Type I form platforms for integrating them? This paper presents four scenarios; each based on a combination of strong/weak Governance Type I and Type II, which are labelled as the ‘Anglo-Saxon’, ‘Saint-Simonian’, ‘Rhineland’ and the ‘European’ Scenarios. The authors prefer the latter, but the best one can hope for in the short term is for this option not to fall by the wayside.

Food Yields and Nutrient Analyses of the Three Sisters: A Haudenosaunee Cropping System

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Jane Mt.Pleasant

2016-11-01

Full Text Available Scholars have studied The Three Sisters, a traditional cropping system of the Haudenosaunee (Iroquois, from multiple perspectives. However, there is no research examining food yields, defined as the quantities of energy and protein produced per unit land area, from the cropping system within Iroquoia. This article compares food yields and other nutrient contributions from the Three Sisters, comprised of interplanted maize, bean and pumpkin, with monocultures of these same crops. The Three Sisters yields more energy (12.25 x 106 kcal/ha and more protein (349 kg/ha than any of the crop monocultures or mixtures of monocultures planted to the same area. The Three Sisters supplies 13.42 people/ha/yr. with energy and 15.86 people/ha/yr. with protein. Nutrient contents of the crops are further enhanced by nixtamalization, a traditional processing technique where maize is cooked in a high alkaline solution. This process increases calcium, protein quality, and niacin in maize.

Cohesion in Online Student Teams versus Traditional Teams

Science.gov (United States)

Hansen, David E.

2016-01-01

Researchers have found that the electronic methods in use for online team communication today increase communication quality in project-based work situations. Because communication quality is known to influence group cohesion, the present research examined whether online student project teams are more cohesive than traditional teams. We tested…

Investigating the settling dynamics of cohesive silt particles with particle-resolving simulations

Science.gov (United States)

Sun, Rui; Xiao, Heng; Sun, Honglei

2018-01-01

The settling of cohesive sediment is ubiquitous in aquatic environments, and the study of the settling process is important for both engineering and environmental reasons. In the settling process, the silt particles show behaviors that are different from non-cohesive particles due to the influence of inter-particle cohesive force. For instance, the flocs formed in the settling process of cohesive silt can loosen the packing, and thus the structural densities of cohesive silt beds are much smaller than that of non-cohesive sand beds. While there is a consensus that cohesive behaviors depend on the characteristics of sediment particles (e.g., Bond number, particle size distribution), little is known about the exact influence of these characteristics on the cohesive behaviors. In addition, since the cohesive behaviors of the silt are caused by the inter-particle cohesive forces, the motions of and the contacts among silt particles should be resolved to study these cohesive behaviors in the settling process. However, studies of the cohesive behaviors of silt particles in the settling process based on particle-resolving approach are still lacking. In the present work, three-dimensional settling process is investigated numerically by using CFD-DEM (Computational Fluid Dynamics-Discrete Element Method). The inter-particle collision force, the van der Waals force, and the fluid-particle interaction forces are considered. The numerical model is used to simulate the hindered settling process of silt based on the experimental setup in the literature. The results obtained in the simulations, including the structural densities of the beds, the characteristic lines, and the particle terminal velocity, are in good agreement with the experimental observations in the literature. To the authors' knowledge, this is the first time that the influences of non-dimensional Bond number and particle polydispersity on the structural densities of silt beds have been investigated separately

A Reappraisal of Lexical Cohesion in Conversational Discourse

Science.gov (United States)

Gomez Gonzalez, Maria De Los Angeles

2013-01-01

Cohesion, or the connectedness of discourse, has been recognized as playing a crucial role in both language production and comprehension processes. Researchers have debated about the "right" number and classification of cohesive devices, as well as about their interaction with coherence and/or genre. The present study proposes an integrative model…

Anisotropy in cohesive, frictional granular media

International Nuclear Information System (INIS)

Luding, Stefan

2005-01-01

The modelling of cohesive, frictional granular materials with a discrete particle molecular dynamics is reviewed. From the structure of the quasi-static granular solid, the fabric, stress, and stiffness tensors are determined, including both normal and tangential forces. The influence of the material properties on the flow behaviour is also reported, including relations between the microscopic attractive force and the macroscopic cohesion as well as the dependence of the macroscopic friction on the microscopic contact friction coefficient. Related to the dynamics, the anisotropy of both structure and stress are exponentially approaching the maximum

Emerging technologies, innovative teachers and moral cohesion

CSIR Research Space (South Africa)

Batchelor, J

2012-05-01

Full Text Available efficacy when they engage with emerging technologies. The concept of moral cohesion is further expanded and forms the main focus of this article. Keywords: emerging technologies, innovative teachers, moral cohesion, pedagogies, ethics, teacher.... African Renaissance and teacher disposition is identified as the strongest drivers. Teacher training forms the link between the strong drivers and the outcomes manifest as Stewardship and ethical considerations. 3.2 Professional Burden The theme...

Britishness and Community Cohesion in Muslim News Online

Directory of Open Access Journals (Sweden)

Hassen ZRIBA

2013-12-01

Full Text Available The issues of British national identity and social cohesion have become pressing concerns within the multicultural fabric of contemporary British society. The increasing number of immigrants and their offspring, along with the maintenance of their cultural roots, seem to represent a serious defiance to social cohesion and the alleged “purity” of Britishness. A number of race related reports were produced by the official authorities to churn out the necessary steps to be followed by the British (immigrants and host community in order to keep social stability and community cohesion. Thus, the politics of community cohesion came to the fore as the neologism of contemporary British political discourse. Such new discourse of governance has been digested and processed differently by different mass media. It has been decoded, for instance, preferably by mainstream news agencies like BBC News Online. However, arguably, it is read appositionally or at best negotiatedly by ethnicity-related news agencies such as Muslim News Online. In this article, attempt has been made to adopt media discourse analysis tools to decipher the ways Muslim News Online decoded and then encoded the hegemonic official discourses of Britishness and community cohesion. A critical and interpretative approach is used to accomplish such study. The corpus of this study is primarily extracted from the website of the Muslim News Online.

[Analysis of genomic copy number variations in two sisters with primary amenorrhea and hyperandrogenism].

Science.gov (United States)

Zhang, Yanliang; Xu, Qiuyue; Cai, Xuemei; Li, Yixun; Song, Guibo; Wang, Juan; Zhang, Rongchen; Dai, Yong; Duan, Yong

2015-12-01

To analyze genomic copy number variations (CNVs) in two sisters with primary amenorrhea and hyperandrogenism. G-banding was performed for karyotype analysis. The whole genome of the two sisters were scanned and analyzed by array-based comparative genomic hybridization (array-CGH). The results were confirmed with real-time quantitative PCR (RT-qPCR). No abnormality was found by conventional G-banded chromosome analysis. Array-CGH has identified 11 identical CNVs from the sisters which, however, overlapped with CNVs reported by the Database of Genomic Variants (http://projects.tcag.ca/variation/). Therefore, they are likely to be benign. In addition, a -8.44 Mb 9p11.1-p13.1 duplication (38,561,587-47,002,387 bp, hg18) and a -80.9 kb 4q13.2 deletion (70,183,990-70,264,889 bp, hg18) were also detected in the elder and younger sister, respectively. The relationship between such CNVs and primary amenorrhea and hyperandrogenism was however uncertain. RT-qPCR results were in accordance with array-CGH. Two CNVs were detected in two sisters by array-CGH, for which further studies are needed to clarify their correlation with primary amenorrhea and hyperandrogenism.

Three Sisters Dam: Investigations and monitoring

International Nuclear Information System (INIS)

Slopek, R.J.; Courage, L.J.R.; Keys, R.A.

1990-01-01

The geotechnical investigations, monitoring and interpretation of data associated with the evaluation of the Three Sisters Dam, which has been suffering from excessive seepage and is in need of enhancement, are outlined. The Three Sisters Dam is located in the continental ranges of the Rocky Mountains in Alberta, impounding the Spray Reservoir, and is founded on 60 m of interbedded sand, gravel, silt and clay layers. The computer code PC-SEEP was used to evaluate seepage. Details are provided of drilling, ground-penetrating radar surveys, seismic surveys, penstock inspection, sinkhole activity, piezometer monitoring, silt wells, settlement monuments, and tailrace monitoring. The intensive investigations of the foundations showed that they consist of a complex formation of interfingered stratified layers and leases of talus and glaciofluvial deposits. Due to the depth and nature of these materials drill hole penetration was limited to the use of the Becker hammer. This equipment successfully delineated the major soil horizons of the foundation. The continued information attained from inspection, drilling, testing, radar surveys, seismic work, monitoring of piezometers, leakage, silt wells and settlement monuments indicated that there are no large voids within the foundation of the dam. 2 refs., 12 figs

Microzonation Analysis of Cohesionless and Cohesive Soil

Directory of Open Access Journals (Sweden)

Tan Choy Soon

2017-01-01

Full Text Available Urban seismic risk is a continuous worldwide issue, numerous researchers are putting great effort in dealing with how to minimise the level of the threat. The only way to minimise the social and economic consequences caused but the seismic risk is through comprehensive earthquake scenario analysis such as ground response analysis. This paper intends to examine the characteristic of shear wave velocity and peak ground acceleration on cohesionless and cohesiveness soil. In order to examine the characteristic of shear wave velocity and peak ground acceleration on cohesionless and cohesiveness soil, ground response analysis was performed using Nonlinear Earthquake Site Response Analysis (NERA and Equivalent-linear Earthquake Site Response Analysis (EERA. The value of ground acceleration was initially high at bedrock and vanishes during the propagation process. It is thus, the measured acceleration at surface is therefore much lower as compare to at bedrock. Result shows that seismic waves can travel faster in harder soil as compared to softer soil. Cohesive soil contributes more to the shaking amplification than cohesionless soil such as sand and harder soil. This is known as local site effect. The typical example is the Mexico Earthquake that happened in 1985. As conclusion, peak ground acceleration for cohesive soil is higher than in cohesionless soil.

Rotational Failure of Rubble-pile Bodies: Influences of Shear and Cohesive Strengths

Science.gov (United States)

Zhang, Yun; Richardson, Derek C.; Barnouin, Olivier S.; Michel, Patrick; Schwartz, Stephen R.; Ballouz, Ronald-Louis

2018-04-01

The shear and cohesive strengths of a rubble-pile asteroid could influence the critical spin at which the body fails and its subsequent evolution. We present results using a soft-sphere discrete element method to explore the mechanical properties and dynamical behaviors of self-gravitating rubble piles experiencing increasing rotational centrifugal forces. A comprehensive contact model incorporating translational and rotational friction and van der Waals cohesive interactions is developed to simulate rubble-pile asteroids. It is observed that the critical spin depends strongly on both the frictional and cohesive forces between particles in contact; however, the failure behaviors only show dependence on the cohesive force. As cohesion increases, the deformation of the simulated body prior to disruption is diminished, the disruption process is more abrupt, and the component size of the fissioned material is increased. When the cohesive strength is high enough, the body can disaggregate into similar-size fragments, which could be a plausible mechanism to form asteroid pairs or active asteroids. The size distribution and velocity dispersion of the fragments in high-cohesion simulations show similarities to the disintegrating asteroid P/2013 R3, indicating that this asteroid may possess comparable cohesion in its structure and experience rotational fission in a similar manner. Additionally, we propose a method for estimating a rubble pile’s friction angle and bulk cohesion from spin-up numerical experiments, which provides the opportunity for making quantitative comparisons with continuum theory. The results show that the present technique has great potential for predicting the behaviors and estimating the material strengths of cohesive rubble-pile asteroids.

Long Fibre Composite Modelling Using Cohesive User's Element

International Nuclear Information System (INIS)

Kozak, Vladislav; Chlup, Zdenek

2010-01-01

The development glass matrix composites reinforced by unidirectional long ceramic fibre has resulted in a family of very perspective structural materials. The only disadvantage of such materials is relatively high brittleness at room temperature. The main micromechanisms acting as toughening mechanism are the pull out, crack bridging, matrix cracking. There are other mechanisms as crack deflection etc. but the primer mechanism is mentioned pull out which is governed by interface between fibre and matrix. The contribution shows a way how to predict and/or optimise mechanical behaviour of composite by application of cohesive zone method and write user's cohesive element into the FEM numerical package Abaqus. The presented results from numerical calculations are compared with experimental data. Crack extension is simulated by means of element extinction algorithms. The principal effort is concentrated on the application of the cohesive zone model with the special traction separation (bridging) law and on the cohesive zone modelling. Determination of micro-mechanical parameters is based on the combination of static tests, microscopic observations and numerical calibration procedures.

IMPLEMENTASI SISTER PROVINCE PROVINSI JAWA TENGAH DENGAN NEGARA BAGIAN QUEENSLAND AUSTRALIA DI BIDANG PERTANIAN

Directory of Open Access Journals (Sweden)

Reni Windiani

2016-02-01

Full Text Available Globalization on national context has insisted the central government to work together and share duties and rights with the local government in order to achieve the national interest.  In Indonesia, UU 32/2004 about local government provide the chance for them to become more active in foreign policy, such as doing the cooperation in sister province/sister city program. The Central Java Province had done many sister province/sister city program with some partners aboard, such as Fujian province (China, Chungchoeng buk-do province (South Korea and the Queensland province (Australia.  The cooperation cover many sectors such as agriculture, city and village development, transportation and tourism, industry, trade and infestation, education, science and technology, and other sectors that will be confer in advance. From all of the cooperation that have been done between Central Java Province and Queensland, the author, is interested to have research on farming, because central government has had many cows imported from Australia.  This research is become important because central java province is one of the major of national fresh meat distributors. This research is using a qualitative method, with descriptive type of research.  This research has three research questions: How effective is the Sister Province program in Central Java with the Queensland in farm sector? What is the obstacle that holds the Sister Province program in Central Java with the Queensland in farm sector? How is the prospect of Sister Province program in Central Java with the Queensland in farm sector? This result of this research is to prove that the implementation of Sister Province program in Central Java with the Queensland in farm sectors is not effective.  Some of the implementation variables of this program have not been fulfilled. Communication, financial resources and bureaucracy structure are some of the variables that have weakness on this program.  Act of

Interactive effects of team cohesion on perceived efficacy in semi-professional sport.

Science.gov (United States)

Marcos, Francisco Miguel Leo; Miguel, Pedro Antonio Sánchez; Oliva, David Sánchez; Calvo, Tomás García

2010-01-01

The present study examined the relationships among cohesion, self-efficacy, coaches' perceptions of their players' efficacy at the individual level and athletes' perceptions of their teammates' efficacy. Participants (n = 76) recruited from four semi- professional soccer and basketball teams completed cohesiveness and efficacy questionnaires who. Data were analyzed through a correlational methodology. Results indicated significant correlations between self-efficacy and task cohesion and social cohesion. Regression analysis results suggest task cohesion positively related to coaches and teammate's perception of efficacy. These results have implications for practitioners in terms of the importance of team building to enhance team cohesion and feelings of efficacy. Key pointsThis paper increases the knowledge about soccer and basketball match analysis.Give normative values to establish practice and match objectives.Give applications ideas to connect research with coaches' practice.

Understanding Social Cohesion Differences in Common Interest Housing Developments

NARCIS (Netherlands)

Dam, van R.I.; Eshuis, J.; Twist, van M.J.W.; Anquetil, V.

2014-01-01

The worldwide upsurge of common interest housing developments (CIDs) has stirred up debates regarding community development and social cohesion. Critics have argued that CIDs lack social cohesion because people regulate the community via rules and contracts rather than through social relationships

Anaphoric Referencing: A Cohesive Device in Written and Spoken ...

African Journals Online (AJOL)

unique firstlady

cohesive function "if and when they can be interpreted through their relation to some other (explicit) encoding device in the same passage". ... is Anaphoric but when the implicit term precedes its linguistic referent, the cohesive tie is known as ...

Substitution as a Device of Grammatical Cohesion in English Contexts

Directory of Open Access Journals (Sweden)

Mohammad Reza Hasannejad

2012-05-01

Full Text Available The present study set out to investigate the effect of teaching substitution as a kind of grammatical cohesion on the true identification of confusing substitution elements with cohesive or non-cohesive roles in different contexts and also the production of modal, reporting and conditional contexts through clausal substitution acquaintance. To this end, the following procedures were taken. First 120 male and female EFL students were selected from Iranshahr Azad University. Having administered the language proficiency test, researchers selected 80 students as intermediate subjects according to their TOEFL band scores. First, pretests of cohesion identification (substitution and production of modal, reporting and conditional environments were administered to both control and experimental groups. Then, the experimental group was exposed to the teaching of the above-said above-mentioned cohesive device. Finally, post-tests of substitution elements’ identification and modal, reporting and conditional contexts’ production through clausal substitution familiarity were administered. The results showed that cohesive device treatment helped students on the true identification of substitution elements. Another finding proved that EFL students might have no difficulty in learning certain rules or classification of rules and application of their clausal substitution knowledge in creating modal, reporting and conditional contexts. Our findings can have implications for the field of language learning and teaching.

Group cohesion in sports teams of different professional level

Directory of Open Access Journals (Sweden)

Vazha M. Devishvili

2017-12-01

Full Text Available Background. Team sports are not only the most exciting sporting events. but also complex activities that make serious demands on players. The effectiveness of the team depends not only on the high level of gaming interaction. but also on the relationship between the players. The work is based on the material of sports teams and is devoted to the study of the phenomenon of group cohesion. As a basic model. the authors choose a 4-factor model that describes cohesion in sports teams. The paper also considered the phenomenon of the emergence of the aggregate subject in the process of joint activity. when the participants feel themselves as a whole and experience feelings of satisfaction and a surge of energy. Objective. The main objective of the work is to investigate the relationship between the level of team cohesion and subjective feelings of unity of its players. As additional variables in the study there is a sport (football and volleyball and team level (amateur and professional. To test the assumptions. two methods were used (the Sport Team Cohesion Questionnaire and the Subject Unity Index. which allow not only to determine the overall level of cohesion and unity. but also to reveal the structure of both phenomena. The study involved two men’s volleyball and two men’s football teams of different ages: 8-9 years (39 athletes; 12-14 years (24 athletes and 18-25 years (41 athletes. Design. For amateur groups represented by children’s and teenage sports teams. significant correlations between unity and unity were obtained (r = 0.618. p <0.01; r = 0.477. p <0.05. For professional teams. no significant correlations were found. Influence of the sport on cohesion is also different for amateur and professional teams. In the first case. the cohesion is higher for football players (U = 118. p <0.05. and in the second case for volleyball players (U = 124. p <0.05. Results. The findings indicate that the professional level of players affects group

IVF for premature ovarian failure: first reported births using oocytes donated from a twin sister.

LENUS (Irish Health Repository)

Sills, Eric Scott

2010-01-01

BACKGROUND: Premature ovarian failure (POF) remains a clinically challenging entity because in vitro fertilisation (IVF) with donor oocytes is currently the only treatment known to be effective. METHODS: A 33 year-old nulligravid patient with a normal karyotype was diagnosed with POF; she had a history of failed fertility treatments and had an elevated serum FSH (42 mIU\\/ml). Oocytes donated by her dizygotic twin sister were used for IVF. The donor had already completed a successful pregnancy herself and subsequently produced a total of 10 oocytes after a combined FSH\\/LH superovulation regime. These eggs were fertilised with sperm from the recipient\\'s husband via intracytoplasmic injection and two fresh embryos were transferred to the recipient on day three. RESULTS: A healthy twin pregnancy resulted from IVF; two boys were delivered by caesarean section at 39 weeks\\' gestation. Additionally, four embryos were cryopreserved for the recipient\\'s future use. The sister-donor achieved another natural pregnancy six months after oocyte retrieval, resulting in a healthy singleton delivery. CONCLUSION: POF is believed to affect approximately 1% of reproductive age females, and POF patients with a sister who can be an oocyte donor for IVF are rare. Most such IVF patients will conceive from treatment using oocytes from an anonymous oocyte donor. This is the first report of births following sister-donor oocyte IVF in Ireland. Indeed, while sister-donor IVF has been successfully undertaken by IVF units elsewhere, this is the only known case where oocyte donation involved twin sisters. As with all types of donor gamete therapy, pre-treatment counselling is important in the circumstance of sister oocyte donation.

Adsorption induced losses in interfacial cohesion

International Nuclear Information System (INIS)

Asaro, R.J.

1977-07-01

A model for interfacial cohesion is developed which describes the loss in the strength of an interface due to the segregation and adsorption of impurities on it. Distinctions are made between interface separations that occur too rapidly for any significant redistribution of adsorbing matter to take place and separations that are slow enough to allow full adsorption equilibrium. Expressions for the total work of complete decohesion are presented for both cases. The results are applied to well-known model adsorption isotherms and some experimental data for grain boundary adsorption of phosphorus in iron is analyzed with respect to the losses in intergranular cohesion

Are diverse societies less cohesive? Testing contact and mediated contact theories.

Science.gov (United States)

McKenna, Sarah; Lee, Eunro; Klik, Kathleen A; Markus, Andrew; Hewstone, Miles; Reynolds, Katherine J

2018-01-01

Previous research has demonstrated that there is a negative relationship between ethnic diversity in a local community and social cohesion. Often the way social cohesion is assessed, though, varies across studies and only some aspects of the construct are included (e.g., trust). The current research explores the relationship between diversity and social cohesion across a number of indicators of social cohesion including neighbourhood social capital, safety, belonging, generalized trust, and volunteering. Furthermore, social psychological theories concerning the role of positive contact and its impact on feelings of threat are investigated. Using a sample of 1070 third generation 'majority' Australians and structural equation modelling (SEM), findings suggest ethnic diversity is related to positive intergroup contact, and that contact showed beneficial impacts for some indicators of social cohesion both directly and indirectly through reducing perceived threat. When interethnic contact and perceived threat are included in the model there is no direct negative effect between diversity and social cohesion. The theoretical implications of these findings are outlined including the importance of facilitating opportunities for positive contact in diverse communities.

Personality in teams: its relationship to social cohesion, task cohesion, and team performance

NARCIS (Netherlands)

van Vianen, A.E.M.; de Dreu, C.K.W.

2001-01-01

This study continued past research on the relationship between personality composition in teams and social cohesion and team performance (Barrick, Stewart, Neubert, & Mount, 1998). Results from the Barrick et al. sample (N = 50) were compared with data from two new samples, one comprising drilling

Catholic nursing sisters and brothers and racial justice in mid-20th-century America.

Science.gov (United States)

Wall, Barbra Mann

2009-01-01

This historical article considers nursing's work for social justice in the 1960s civil rights movement through the lens of religious sisters and brothers who advocated for racial equality. The article examines Catholic nurses' work with African Americans in the mid-20th century that took place amid the prevailing social conditions of poverty and racial disempowerment, conditions that were linked to serious health consequences. Historical methodology is used within the framework of "bearing witness," a term often used in relation to the civil rights movement and one the sisters themselves employed. Two situations involving nurses in the mid-20th century are examined: the civil rights movement in Selma, Alabama, and the actions for racial justice in Chicago, Illinois. The thoughts and actions of Catholic sister and brother nurses in the mid-20th century are chronicled, including those few sister nurses who stepped outside their ordinary roles in an attempt to change an unjust system entirely.

Living with a brother or sister with epilepsy: siblings' experiences.

Science.gov (United States)

Hames, Annette; Appleton, Richard

2009-12-01

There is conflicting evidence about the impact of disability upon siblings, and very little research on the siblings of children with epilepsy. There is some evidence that siblings who have less accurate information exhibit more distress. The aim of this study was to assess siblings' response to having a brother or sister with epilepsy and to begin to develop information for them. Parents of children attending paediatric neurology outpatient departments were invited to participate in a pilot study. Parents who consented to take part were asked if they had previously received information for siblings. Parents and siblings participated in a semi-structured interview and siblings were also invited to submit a personal account of living with a brother or sister who had epilepsy. Twenty-five families with a child with epilepsy aged 2.5-15 years initially agreed to take part. None of the families stated that they had ever seen or received any information specifically for siblings. Fourteen siblings from the 25 families, aged 8-25 years, provided a personal account of what it was like living with a brother or sister with epilepsy. Siblings' accounts included both negative and positive feelings, and specifically feelings of care and love for their sibling. This initial study suggests that siblings of children with epilepsy have many positive but also early negative feelings. The results are limited by the size of the study, the fact that most siblings were older sisters, and the mean time since diagnosis was 6 years. Finally, it is hoped that the personal accounts collected in this study will be published for the benefit of other siblings of children with epilepsy.

Derivation of Path Independent Coupled Mix Mode Cohesive Laws from Fracture Resistance Curves

DEFF Research Database (Denmark)

Goutianos, Stergios

2016-01-01

A generalised approach is presented to derive coupled mixed mode cohesive laws described with physical parameters such as peak traction, critical opening, fracture energy and cohesive shape. The approach is based on deriving mix mode fracture resistance curves from an effective mix mode cohesive...... law at different mode mixities. From the fracture resistance curves, the normal and shear stresses of the cohesive laws can be obtained by differentiation. Since, the mixed mode cohesive laws are obtained from a fracture resistance curve (potential function), path independence is automatically...

Packing and Cohesive Properties of Some Locally Extracted Starches

African Journals Online (AJOL)

... properties of the particles affect the packing and cohesive properties of the starches, and are important in predicting the behaviour of the starches during handling and use in pharmaceutical preparations. These properties need to be closely controlled in pre-formulation studies. Keywords: Packing and cohesive properties, ...

Spinal involvement in Camptodactyly Arthropathy Coxa-vara Pericarditis (CACP) syndrome in two Yemeni sisters

NARCIS (Netherlands)

Emad, Yasser; Ragab, Yasser; Ibrahim, Osama; Khalifa, Maher; Dawood, Ahmed; Rasker, Johannes J.

2017-01-01

Aim of the work The objective of this clinical report is to describe the detailed magnetic resonance imaging (MRI) findings of the spine, knee and hip joints in two young sisters with Camptodactyly Arthropathy Coxa-vara Pericarditis (CACP) syndrome. Cases report In two young sisters, both had normal

Brothers and Sisters of Adults with Mental Retardation: Gendered Nature of the Sibling Relationship.

Science.gov (United States)

Orsmond, Gael I.; Seltzer, Marsha Mailick

2000-01-01

Differences and similarities between 245 brothers and sisters of adults with mental retardation in the sibling relationship were examined. Sisters scored higher in the caregiving, companionship, and positive affect aspects of the sibling relationship. Sibling involvement increased over time, but was dependent upon changes in maternal health.…

Two Sisters with Idiopathic Pulmonary Hemosiderosis

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Mehmet Gencer

2007-01-01

Full Text Available Idiopathic pulmonary hemosiderosis (IPH is a rare cause of diffuse alveolar hemorrhage with unknown etiology. In the present report, the presentations of two sisters are described: one sister had IPH, eosinophilia and a high serum immunoglobulin E (IgE level; and the other had IPH, pneumothorax, eosinophilia and a high serum IgE level. Both cases had quite unusual presentations. The first patient was 23 years of age, and had suffered from dry cough and progressive dyspnea for four years. Her hemoglobin level was 60 g/L, total serum IgE level was 900 U/mL and eosinophilia was 9%. Her chest radiography revealed diffuse infiltration. She died due to respiratory failure. The second patient was 18 years of age. She had also suffered from dry cough and gradually increasing dyspnea for two years. She had partial pneumothorax in the right lung and diffuse infiltration in other pulmonary fields on chest radiography. Her hemoglobin level was 99 g/L, total serum IgE level was 1200 U/mL and eosinophilia was 8%. IPH was diagnosed by open lung biopsy. All these findings suggested that familial or allergic factors, as well as immunological factors, might have contributed to the etiology of IPH.

Identical Twin Primigravid Sisters -Spontaneous Labour and ...

African Journals Online (AJOL)

We report 2 cases of identical twin sisters, the older sibling getting married 14 months earlier but both got pregnant for their first child at about the same time and were managed by the same Obstetrician and fell into spontaneous labour within a few hours of each other. Both were delivered by emergency caesarean section ...

Brownfield regeneration: Towards strengthening social cohesion?

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Minić Marta

2016-01-01

Full Text Available In broader terms, the paper refers to the topic of brownfield regeneration, as one of the most complex mechanisms for sustainable spatial development. In addition to the fact that brownfield regeneration demands a variety of instruments, such as: tax subsidies, the change of land use ownership, soil remediation, planning regulative amendments, etc., the complexity of brownfield regeneration is primarily seen in a number of stakeholders participating in such a process. Thus, the paper focuses on the social aspect of brownfield regeneration - precisely, on researching the community role and reviewing the possibilities for achieving the 'local' interests in complex developmental processes. The main research hypothesis is that brownfield regeneration positively affects the creation of and strengthening the social cohesion in the areas close to the brownfield site. More precisley, the paper presents the ways towards strenghtening social cohesion in the initial phase of the brownfield regeneration process, as well as the effects of such a process in its operationalisation phase on social cohesion. The thesis is examined by two main parameters: 1 participation of local community, and 2 social costs and benefits of brownfield regeneration versus greenfield investment. The research results are presented in the form of argumentative essay. In fact, the critical overview of arguments for and against the main research hypothesis is provided based on the review of interdisciplinary literature in the domain of brownfield regeneration. Such research organisation ensures the identification and description of the measures needed for strengthening social cohesion, as an utmost goal of this research. The final research contribution is about offering the guidelines for similar methodological approach in urban research.

UDS and SCE in lymphocytes of persons occupationally exposed to low levels of ionizing radiation

International Nuclear Information System (INIS)

Tuschl, H.; Kovac, R.; Altmann, H.

1983-03-01

Unscheduled DNA synthesis induced by 'in vitro' UV-irradiation was investigated in lymphocytes of persons occupationally exposed to low doses of ionizing radiation (maximum registered radiation dose: 98 mrad/month). For radiation exposures >14 mrad/month, above background level, increased rates of UDS after in vitro UV-irradiation of lymphocytes were found. The bromodeoxyuridine differential chromatid labeling technique was applied to the examination of spontaneous and mytomycin C induced sister chromatid exchanges in the same population. No statistically significant difference could be determined in spontaneously occurring SCEs, while MMC induced SCEs were significantly reduced in persons exposed to radiation doses >14 mrad/month, thus indicating increased repair capability for DNA lesions inflicted by a second insult after protracted low dose irradiation. (Author) [de

[Effects of family cohesion and adaptability on behavioral problems in preschool children].

Science.gov (United States)

Wang, Yan-Ni; Xue, Hong-Li; Chen, Qian

2016-05-01

To investigate the effects of family cohesion and adaptability on behavioral problems in preschool children. The stratified cluster multistage sampling method was used to perform a questionnaire survey in the parents of 1 284 children aged 3-6 years in the urban area of Lanzhou, China. The general status questionnaire, Conners Child Behavior Checklist (Parent Symptom Question), and Family Adaptability and Cohesion Scale, Second edition, Chinese version (FACESII-CV) were used to investigate behavioral problems and family cohesion and adaptability. The overall detection rate of behavioral problems in preschool children was 17.13%. The children with different types of family cohesion had different detection rates of behavioral problems, and those with free-type family cohesion showed the highest detection rate of behavioral problems (40.2%). The children with different types of family adaptability also had different detection rates of behavioral problems, and those with stiffness type showed the highest detection rate of behavioral problems (25.1%). The behavioral problems in preschool children were negatively correlated with family cohesion and adaptability. During the growth of preschool children, family cohesion and adaptability have certain effects on the mental development of preschool children.

Cohesion: An Overview for the Teacher of Reading. Revised.

Science.gov (United States)

Chapman, L. John

Pronouns, substitutes, elipses, conjunctions, synonyms, antonyms, superordinates and subordinates, and part-whole relations all provide cohesive ties that help a reader understand text. A study at Britain's Open University (England) has revealed the way in which the perception of cohesive ties is achieved as children's reading ability grows.…

Freud on Brothers and Sisters: A Neglected Topic

Science.gov (United States)

Sherwin-White, Susan

2007-01-01

This paper explores Freud's developing thought on brothers and sisters, and their importance in his psychoanalytical writings and clinical work. Freud's work on sibling psychology has been seriously undervalued. This paper aims to give due recognition to Freud's work in this area. (Contains 1 note.)

Genome-Wide Analysis of Heteroduplex DNA in Mismatch Repair–Deficient Yeast Cells Reveals Novel Properties of Meiotic Recombination Pathways

Science.gov (United States)

Martini, Emmanuelle; Borde, Valérie; Legendre, Matthieu; Audic, Stéphane; Regnault, Béatrice; Soubigou, Guillaume; Dujon, Bernard; Llorente, Bertrand

2011-01-01

Meiotic DNA double-strand breaks (DSBs) initiate crossover (CO) recombination, which is necessary for accurate chromosome segregation, but DSBs may also repair as non-crossovers (NCOs). Multiple recombination pathways with specific intermediates are expected to lead to COs and NCOs. We revisited the mechanisms of meiotic DSB repair and the regulation of CO formation, by conducting a genome-wide analysis of strand-transfer intermediates associated with recombination events. We performed this analysis in a SK1 × S288C Saccharomyces cerevisiae hybrid lacking the mismatch repair (MMR) protein Msh2, to allow efficient detection of heteroduplex DNAs (hDNAs). First, we observed that the anti-recombinogenic activity of MMR is responsible for a 20% drop in CO number, suggesting that in MMR–proficient cells some DSBs are repaired using the sister chromatid as a template when polymorphisms are present. Second, we observed that a large fraction of NCOs were associated with trans–hDNA tracts constrained to a single chromatid. This unexpected finding is compatible with dissolution of double Holliday junctions (dHJs) during repair, and it suggests the existence of a novel control point for CO formation at the level of the dHJ intermediate, in addition to the previously described control point before the dHJ formation step. Finally, we observed that COs are associated with complex hDNA patterns, confirming that the canonical double-strand break repair model is not sufficient to explain the formation of most COs. We propose that multiple factors contribute to the complexity of recombination intermediates. These factors include repair of nicks and double-stranded gaps, template switches between non-sister and sister chromatids, and HJ branch migration. Finally, the good correlation between the strand transfer properties observed in the absence of and in the presence of Msh2 suggests that the intermediates detected in the absence of Msh2 reflect normal intermediates. PMID

Genome-wide analysis of heteroduplex DNA in mismatch repair-deficient yeast cells reveals novel properties of meiotic recombination pathways.

Directory of Open Access Journals (Sweden)

Emmanuelle Martini

2011-09-01

Full Text Available Meiotic DNA double-strand breaks (DSBs initiate crossover (CO recombination, which is necessary for accurate chromosome segregation, but DSBs may also repair as non-crossovers (NCOs. Multiple recombination pathways with specific intermediates are expected to lead to COs and NCOs. We revisited the mechanisms of meiotic DSB repair and the regulation of CO formation, by conducting a genome-wide analysis of strand-transfer intermediates associated with recombination events. We performed this analysis in a SK1 × S288C Saccharomyces cerevisiae hybrid lacking the mismatch repair (MMR protein Msh2, to allow efficient detection of heteroduplex DNAs (hDNAs. First, we observed that the anti-recombinogenic activity of MMR is responsible for a 20% drop in CO number, suggesting that in MMR-proficient cells some DSBs are repaired using the sister chromatid as a template when polymorphisms are present. Second, we observed that a large fraction of NCOs were associated with trans-hDNA tracts constrained to a single chromatid. This unexpected finding is compatible with dissolution of double Holliday junctions (dHJs during repair, and it suggests the existence of a novel control point for CO formation at the level of the dHJ intermediate, in addition to the previously described control point before the dHJ formation step. Finally, we observed that COs are associated with complex hDNA patterns, confirming that the canonical double-strand break repair model is not sufficient to explain the formation of most COs. We propose that multiple factors contribute to the complexity of recombination intermediates. These factors include repair of nicks and double-stranded gaps, template switches between non-sister and sister chromatids, and HJ branch migration. Finally, the good correlation between the strand transfer properties observed in the absence of and in the presence of Msh2 suggests that the intermediates detected in the absence of Msh2 reflect normal intermediates.

Effect of cohesion on local compaction and granulation of sheared soft granular materials

Directory of Open Access Journals (Sweden)

Roy Sudeshna

2017-01-01

Full Text Available This paper results from an ongoing investigation of the effect of cohesion on the compaction of sheared soft wet granular materials. We compare dry non-cohesive and wet moderately-to-strongly cohesive soft almost frictionless granular materials and report the effect of cohesion between the grains on the local volume fraction. We study this in a three dimensional, unconfined, slowly sheared split-bottom ring shear cell, where materials while sheared are subject to compression under the confining weight of the material above. Our results show that inter-particle cohesion has a considerable impact on the compaction of soft materials. Cohesion causes additional stresses, due to capillary forces between particles, leading to an increase in volume fraction due to higher compaction. This effect is not visible in a system of infinitely stiff particles. In addition, acting oppositely, we observe a general decrease in volume fraction due to increased cohesion for frictional particle, which we attribute to the role of contact friction that enhances dilation.

An examination of the relationship between athlete leadership and cohesion using social network analysis.

Science.gov (United States)

Loughead, Todd M; Fransen, Katrien; Van Puyenbroeck, Stef; Hoffmann, Matt D; De Cuyper, Bert; Vanbeselaere, Norbert; Boen, Filip

2016-11-01

Two studies investigated the structure of different athlete leadership networks and its relationship to cohesion using social network analysis. In Study 1, we examined the relationship between a general leadership quality network and task and social cohesion as measured by the Group Environment Questionnaire (GEQ). In Study 2, we investigated the leadership networks for four different athlete leadership roles (task, motivational, social and external) and their association with task and social cohesion networks. In Study 1, the results demonstrated that the general leadership quality network was positively related to task and social cohesion. The results from Study 2 indicated positive correlations between the four leadership networks and task and social cohesion networks. Further, the motivational leadership network emerged as the strongest predictor of the task cohesion network, while the social leadership network was the strongest predictor of the social cohesion network. The results complement a growing body of research indicating that athlete leadership has a positive association with cohesion.

Transport and deposition of cohesive pharmaceutical powders in human airway

Directory of Open Access Journals (Sweden)

Wang Yuan

2017-01-01

Full Text Available Pharmaceutical powders used in inhalation therapy are in the size range of 1-5 microns and are usually cohesive. Understanding the cohesive behaviour of pharmaceutical powders during their transportation in human airway is significant in optimising aerosol drug delivery and targeting. In this study, the transport and deposition of cohesive pharmaceutical powders in a human airway model is simulated by a well-established numerical model which combines computational fluid dynamics (CFD and discrete element method (DEM. The van der Waals force, as the dominant cohesive force, is simulated and its influence on particle transport and deposition behaviour is discussed. It is observed that even for dilute particle flow, the local particle concentration in the oral to trachea region can be high and particle aggregation happens due to the van der Waals force of attraction. It is concluded that the deposition mechanism for cohesive pharmaceutical powders, on one hand, is dominated by particle inertial impaction, as proven by previous studies; on the other hand, is significantly affected by particle aggregation induced by van der Waals force. To maximum respiratory drug delivery efficiency, efforts should be made to avoid pharmaceutical powder aggregation in human oral-to-trachea airway.

Transport and deposition of cohesive pharmaceutical powders in human airway

Science.gov (United States)

Wang, Yuan; Chu, Kaiwei; Yu, Aibing

2017-06-01

Pharmaceutical powders used in inhalation therapy are in the size range of 1-5 microns and are usually cohesive. Understanding the cohesive behaviour of pharmaceutical powders during their transportation in human airway is significant in optimising aerosol drug delivery and targeting. In this study, the transport and deposition of cohesive pharmaceutical powders in a human airway model is simulated by a well-established numerical model which combines computational fluid dynamics (CFD) and discrete element method (DEM). The van der Waals force, as the dominant cohesive force, is simulated and its influence on particle transport and deposition behaviour is discussed. It is observed that even for dilute particle flow, the local particle concentration in the oral to trachea region can be high and particle aggregation happens due to the van der Waals force of attraction. It is concluded that the deposition mechanism for cohesive pharmaceutical powders, on one hand, is dominated by particle inertial impaction, as proven by previous studies; on the other hand, is significantly affected by particle aggregation induced by van der Waals force. To maximum respiratory drug delivery efficiency, efforts should be made to avoid pharmaceutical powder aggregation in human oral-to-trachea airway.

Hypomorphism in human NSMCE2 linked to primordial dwarfism and insulin resistance.

Science.gov (United States)

Payne, Felicity; Colnaghi, Rita; Rocha, Nuno; Seth, Asha; Harris, Julie; Carpenter, Gillian; Bottomley, William E; Wheeler, Eleanor; Wong, Stephen; Saudek, Vladimir; Savage, David; O'Rahilly, Stephen; Carel, Jean-Claude; Barroso, Inês; O'Driscoll, Mark; Semple, Robert

2014-09-01

Structural maintenance of chromosomes (SMC) complexes are essential for maintaining chromatin structure and regulating gene expression. Two the three known SMC complexes, cohesin and condensin, are important for sister chromatid cohesion and condensation, respectively; however, the function of the third complex, SMC5-6, which includes the E3 SUMO-ligase NSMCE2 (also widely known as MMS21) is less clear. Here, we characterized 2 patients with primordial dwarfism, extreme insulin resistance, and gonadal failure and identified compound heterozygous frameshift mutations in NSMCE2. Both mutations reduced NSMCE2 expression in patient cells. Primary cells from one patient showed increased micronucleus and nucleoplasmic bridge formation, delayed recovery of DNA synthesis, and reduced formation of foci containing Bloom syndrome helicase (BLM) after hydroxyurea-induced replication fork stalling. These nuclear abnormalities in patient dermal fibroblast were restored by expression of WT NSMCE2, but not a mutant form lacking SUMO-ligase activity. Furthermore, in zebrafish, knockdown of the NSMCE2 ortholog produced dwarfism, which was ameliorated by reexpression of WT, but not SUMO-ligase-deficient NSMCE. Collectively, these findings support a role for NSMCE2 in recovery from DNA damage and raise the possibility that loss of its function produces dwarfism through reduced tolerance of replicative stress.

Department of Genetics

International Nuclear Information System (INIS)

2000-01-01

Full text: There are five independent research groups in the Department conducting the following lines of investigations: 1. Regulation of sulfur amino acid metabolism in fungi, focusing on cloning and characterisation of structural and regulatory genes in Aspergillus nidulans. 2. Identification and characterization of S. cerevisiae genes involved in the regulation of tRNA biosynthesis and control of translation fidelity in cytosolic and mitochondrial systems. 3. Mechanism of DNA repair and mutagenesis by using mutations in DNA polymerases, mismatch repair and radiation sensitivity genes to study their influence on the generation of mutations in nondividing, resting cells (adaptive mutations) in S. cerevisiae. 4. Pleiotropic effects of the S. cerevisiae IRR1 gene, particularily on colony formation and sister chromatid cohesion. 5. Regulation of heme synthesis in S. cerevisiae: the analysis of structure-function relationship of ferrochelatase (the last enzyme of the pathway). 6. Role of RSP5 the ubiquitin-protein ligase of S. cerevisiae in protein import to mitochondria and endocytosis of plasma membrane proteins. 7. Molecular analysis of the glucose-6-phosphate dehydrogenase gene in Polish 6-GDP deficient subjects. 8. Genetic and phylogenic studies of the Polish Bison bonasus population with the use of nuclear and mitochondrial markers

Timeless links replication termination to mitotic kinase activation.

Directory of Open Access Journals (Sweden)

Jayaraju Dheekollu

2011-05-01

Full Text Available The mechanisms that coordinate the termination of DNA replication with progression through mitosis are not completely understood. The human Timeless protein (Tim associates with S phase replication checkpoint proteins Claspin and Tipin, and plays an important role in maintaining replication fork stability at physical barriers, like centromeres, telomeres and ribosomal DNA repeats, as well as at termination sites. We show here that human Tim can be isolated in a complex with mitotic entry kinases CDK1, Auroras A and B, and Polo-like kinase (Plk1. Plk1 bound Tim directly and colocalized with Tim at a subset of mitotic structures in M phase. Tim depletion caused multiple mitotic defects, including the loss of sister-chromatid cohesion, loss of mitotic spindle architecture, and a failure to exit mitosis. Tim depletion caused a delay in mitotic kinase activity in vivo and in vitro, as well as a reduction in global histone H3 S10 phosphorylation during G2/M phase. Tim was also required for the recruitment of Plk1 to centromeric DNA and formation of catenated DNA structures at human centromere alpha satellite repeats. Taken together, these findings suggest that Tim coordinates mitotic kinase activation with termination of DNA replication.

Sordaria, a model system to uncover links between meiotic pairing and recombination.

Science.gov (United States)

Zickler, Denise; Espagne, Eric

2016-06-01

The mycelial fungus Sordaria macrospora was first used as experimental system for meiotic recombination. This review shows that it provides also a powerful cytological system for dissecting chromosome dynamics in wild-type and mutant meioses. Fundamental cytogenetic findings include: (1) the identification of presynaptic alignment as a key step in pairing of homologous chromosomes. (2) The discovery that biochemical complexes that mediate recombination at the DNA level concomitantly mediate pairing of homologs. (3) This pairing process involves not only resolution but also avoidance of chromosomal entanglements and the resolution system includes dissolution of constraining DNA recombination interactions, achieved by a unique role of Mlh1. (4) Discovery that the central components of the synaptonemal complex directly mediate the re-localization of the recombination proteins from on-axis to in-between homologue axis positions. (5) Identification of putative STUbL protein Hei10 as a structure-based signal transduction molecule that coordinates progression and differentiation of recombinational interactions at multiple stages. (6) Discovery that a single interference process mediates both nucleation of the SC and designation of crossover sites, thereby ensuring even spacing of both features. (7) Discovery of local modulation of sister-chromatid cohesion at sites of crossover recombination. Copyright © 2016 Elsevier Ltd. All rights reserved.

Relationship Among Team Collective Efficacy, Cohesion, and Coaching Competency in Sports

OpenAIRE

Manning, Clayton T.

2007-01-01

A team's performance in any sport can be predicted by many factors. Some of these factors include team collective efficacy, team cohesiveness, and coaching competency. Currently, there is little research investigating the relationships among teams' beliefs about their capabilities, their level of cohesion, and their perceptions of coaching competency on overall sport performance. The purpose of this study was to document the relationship among collective efficacy, cohesion, and coaching on sp...

Mixed Mode cohesive law with interface dilatation

DEFF Research Database (Denmark)

Sørensen, Bent F.; Goutianos, Stergios

2014-01-01

displacements. As the crack faces displace relatively to each other, the roughness asperities ride on top of each other and result in an opening (dilatation) in the normal direction. Furthermore, the interaction of the crack surfaces in the contact zone gives rise to compressive normal stresses and frictional...... shear stresses opposing the crack face displacements. A phenomenological Mixed Mode cohesive zone law, derived from a potential function, is developed to describe the above mentioned fracture behaviour under monotonic opening. The interface dilatation introduces two new lengths. The cohesive law...

Immigration, social cohesion, and naturalization

DEFF Research Database (Denmark)

Lægaard, Sune

2010-01-01

social trust do not connect with issues of naturalization at all. Other conceptions of social cohesion are either politically controversial, problematic as part of the justification of stricter naturalization requirements, or in fact justify less demanding naturalization requirements....

Elongational rheology and cohesive fracture of photo-oxidated LDPE

Energy Technology Data Exchange (ETDEWEB)

Rolón-Garrido, Víctor H., E-mail: victor.h.rolongarrido@tu-berlin.de; Wagner, Manfred H. [Chair of Polymer Engineering/Polymer Physics, Berlin Institute of Technology (TU Berlin), Fasanenstrasse 90, D-10623 Berlin (Germany)

2014-01-15

It was found recently that low-density polyethylene (LDPE) samples with different degrees of photo-oxidation represent an interesting system to study the transition from ductile to cohesive fracture and the aspects of the cohesive rupture in elongational flow. Sheets of LDPE were subjected to photo-oxidation in the presence of air using a xenon lamp to irradiate the samples for times between 1 day and 6 weeks. Characterisation methods included Fourier transform infrared spectroscopy, solvent extraction method, and rheology in shear and uniaxial extensional flows. Linear viscoelasticity was increasingly affected by increasing photo-oxidation due to crosslinking of LDPE, as corroborated by the carbonyl index, acid and aldehydes groups, and gel fraction. The molecular stress function model was used to quantify the experimental data, and the nonlinear model parameter β was found to be correlated with the gel content. The uniaxial data showed that the transition from ductile to cohesive fracture was shifted to lower elongational rates, the higher the gel content was. From 2 weeks photo-oxidation onwards, cohesive rupture occurred at every strain rate investigated. The true strain and true stress at cohesive fracture as well as the energy density applied to the sample up to fracture were analyzed. At low gel content, rupture was mainly determined by the melt fraction while at high gel content, rupture occurred predominantly in the gel structure. The strain at break was found to be independent of strain rate, contrary to the stress at break and the energy density. Thus, the true strain and not the stress at break or the energy density was found to be the relevant physical quantity to describe cohesive fracture behavior of photo-oxidated LDPE. The equilibrium modulus of the gel structures was correlated with the true strain at rupture. The stiffer the gel structure, the lower was the deformation tolerated before the sample breaks.

Broad phylogenomic sampling and the sister lineage of land plants.

Directory of Open Access Journals (Sweden)

Ruth E Timme

Full Text Available The tremendous diversity of land plants all descended from a single charophyte green alga that colonized the land somewhere between 430 and 470 million years ago. Six orders of charophyte green algae, in addition to embryophytes, comprise the Streptophyta s.l. Previous studies have focused on reconstructing the phylogeny of organisms tied to this key colonization event, but wildly conflicting results have sparked a contentious debate over which lineage gave rise to land plants. The dominant view has been that 'stoneworts,' or Charales, are the sister lineage, but an alternative hypothesis supports the Zygnematales (often referred to as "pond scum" as the sister lineage. In this paper, we provide a well-supported, 160-nuclear-gene phylogenomic analysis supporting the Zygnematales as the closest living relative to land plants. Our study makes two key contributions to the field: 1 the use of an unbiased method to collect a large set of orthologs from deeply diverging species and 2 the use of these data in determining the sister lineage to land plants. We anticipate this updated phylogeny not only will hugely impact lesson plans in introductory biology courses, but also will provide a solid phylogenetic tree for future green-lineage research, whether it be related to plants or green algae.

Evaluating Lexical Cohesion in Nigerian Newspaper Genres: Focus on the Editorials

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Zubairu Malah

2016-11-01

Full Text Available Applied linguists paying scholarly attention to newspaper genres have often argued that findings emerging from such studies would be of pedagogical significance because most of the newspaper genres share certain conventional features with school genres. Similarly, this study explored lexical cohesion in newspaper editorials, and it is understood that the findings could help learners in handling persuasive writings. The study sought to identify the dominant sources of lexical cohesion in the editorials, and also to examine how lexical cohesion is utilized to achieve coherence in the editorials. Drawing on Systemic Functional Linguistics (SFL, the study applied Eggins’ (2004 model of lexical cohesion and analyzed 30 editorial texts of 20, 354 words drawn from three major Nigerian newspapers: The Guardian, The Nation, and Vanguard. The analysis revealed 2, 685 ties across 849 sentences. The data demonstrated that the major types of lexical cohesion in the editorials include: repetition (49.5%, expectancy relations (15. 8%, class/sub-class (11%, and synonymy (10.8%. It was further revealed that lexical cohesion devices, which formed into chains (586 and isolated ties (837, were utilized in building coherence in the editorial texts. It was finally shown how findings of the study could be beneficial in ESP, EAP, and EGP learning, especially in persuasive writings.

Cohesion and device reliability in organic bulk heterojunction photovoltaic cells

KAUST Repository

Brand, Vitali; Bruner, Christopher; Dauskardt, Reinhold H.

2012-01-01

that the phase separated bulk heterojunction layer is the weakest layer and report quantitative cohesion values which ranged from ∼1 to 20 J m -2. The effects of layer thickness, composition, and annealing treatments on layer cohesion are investigated. Using

Differences by Sexual Orientation in Perceptions of Neighborhood Cohesion: Implications for Health.

Science.gov (United States)

Henning-Smith, Carrie; Gonzales, Gilbert

2018-06-01

A large body of research documents the relationship between health and place, including the positive association between neighborhood cohesion and health. However, very little research has examined neighborhood cohesion by sexual orientation. This paper addresses that gap by examining differences in perceived neighborhood cohesion by sexual orientation. We use data from the 2016 National Health Interview Survey (n = 28,164 respondents aged 18 years and older) to examine bivariate differences by sexual orientation in four measures of neighborhood cohesion. We then use ordered logistic regression models to assess the relationship between sexual orientation and a scaled measure of neighborhood cohesion, adjusting for socio-demographic characteristics, living arrangements, health status, region, and neighborhood tenure. We find that lesbian, gay, and bisexual (LGB) adults are less likely to say that they live in a close-knit neighborhood (54.6 vs. 65.6%, p < 0.001), they can count on their neighbors (74.7 vs. 83.1%, p < 0.001), they trust their neighbors (75.5 vs. 83.7%, p < 0.001), or people in their neighborhood help each other out (72.9 vs. 83.1%, p < 0.001), compared to heterosexual adults. Even after controlling for socio-demographic factors, neighborhood cohesion scores are lower for LGB adults compared to heterosexual adults (odds ratio of better perceived neighborhood cohesion for sexual minorities: 0.70, p < 0.001). Overall, LGB adults report worse neighborhood cohesion across multiple measures, even after adjusting for individual characteristics and neighborhood tenure. Because living in a cohesive neighborhood is associated with better health outcomes, future research, community-level initiatives, and public policy efforts should focus on creating welcoming neighborhood environments for sexual minorities.

Differences in neighborhood social cohesion and aerobic physical activity by Latino subgroup

Directory of Open Access Journals (Sweden)

Rosenda Murillo

2016-12-01

Full Text Available Previous research has examined the role of neighborhood social cohesion in physical activity outcomes; however, less is known about this relationship across Latino subgroups. The purpose of our study was to examine the association between neighborhood social cohesion and aerobic leisure-time physical activity (LTPA among Latino adults and to determine whether these associations differ by Latino subgroup. We used cross-sectional 2013–2014 National Health Interview Survey (NHIS data on Latinos originating from 5 countries/regions (i.e., Latinos of Puerto Rican, Mexican/Mexican-American, Cuban/Cuban-American, Dominican and Central or South American origin aged ≥18 years (n=11,126. Multivariable logistic regression models were used to estimate associations between self-reported neighborhood social cohesion and meeting aerobic LTPA guidelines. Models were adjusted for age, sex, education, and acculturation. We also investigated whether associations varied by Latino subgroup. In adjusted models for all Latino adults, compared with those reporting low social cohesion, individuals who reported high social cohesion (Odds Ratio [OR]: 1.33; 95% Confidence Interval [CI]: 1.17–1.52 were significantly more likely to meet the aerobic physical activity guideline. When stratified by Latino subgroups, among Mexican/Mexicans-Americans (OR: 1.39; 95% CI: 1.16, 1.66 and Cuban/Cuban Americans (OR: 1.73; 95% CI: 1.00, 2.97 high social cohesion was associated with meeting the aerobic activity guideline. Among Dominicans, those who reported medium social cohesion (OR: 0.52, 95% CI: 0.29, 0.93 were less likely to meet the aerobic activity guideline. When examining aerobic physical activity outcomes in the Latino population, the role of neighborhood social cohesion and the variability among Latino subgroups should be considered. Keywords: Neighborhood social cohesion, Physical activity, Latinos, subgroups

Authentic leadership, group cohesion and group identification in security and emergency teams.

Science.gov (United States)

García-Guiu López, Carlos; Molero Alonso, Fernando; Moya Morales, Miguel; Moriano León, Juan Antonio

2015-01-01

Authentic leadership (AL) is a kind of leadership that inspires and promotes positive psychological capacities, underlining the moral and ethical component of behavior. The proposed investigation studies the relations among AL, cohesion, and group identification in security and emergency teams. A cross-sectional research design was conducted in which participated 221 members from 26 fire departments and operative teams from the local police of three Spanish provinces. The following questionnaires were administered: Authentic Leadership (ALQ), Group Cohesion (GEQ), and Mael and Ashford's Group Identification Questionnaire. A direct and positive relation was found between AL, cohesion, and group identification. An indirect relation was also found between AL and group cohesion through group identification, indicating the existence of partial mediation. The utility of the proposed model based on AL is considered; this model can be employed by those in charge of the fire departments and operative groups in organizations to improve workteams' cohesion. Both AL and group identification help to explain group cohesion in organizations committed to security and emergencies.

Psychopathology, childhood trauma, and personality traits in patients with borderline personality disorder and their sisters.

Science.gov (United States)

Laporte, Lise; Paris, Joel; Guttman, Herta; Russell, Jennifer

2011-08-01

The aim of this study was to document and compare adverse childhood experiences, and personality profiles in women with borderline personality disorder (BPD) and their sisters, and to determine how these factors impact current psychopathology. Fifty-six patients with BPD and their sisters were compared on measures assessing psychopathology, personality traits, and childhood adversities. Most sisters showed little evidence of psychopathology. Both groups reported dysfunctional parent-child relationships and a high prevalence of childhood trauma. Subjects with BPD reported experiencing more emotional abuse and intrafamilial sexual abuse, but more similarities than differences between probands and sisters were found. In multilevel analyses, personality traits of affective instability and impulsivity predicted DIB-R scores and SCL-90-R scores, above and beyond trauma. There were few relationships between childhood adversities and other measures of psychopathology. Sensitivity to adverse experiences, as reflected in the development of psychopathology, appears to be influenced by personality trait profiles.

El naturalismo americano: Theodore Dreiser y Sister Carrie

Directory of Open Access Journals (Sweden)

Dolores G. ALONSO MULAS

2009-08-01

Full Text Available Para situar a un escritor, como Theodore Dreiser, y especialmente su novela Sister Carrie dentro de un movimiento literario y de una etapa determinada de la historia americana, es necesario dar un breve repaso al naturalismo, llegado a América a través de Stephen Crane

"If I only touch her cloak": the Sisters of Charity of St. Joseph in New Orleans hospital, 1834-1860.

Science.gov (United States)

Kong, Hyejung Grace; Kim, Ock-Joo

2015-04-01

This study is about the Sisters of Charity of St. Joseph in New Orleans' Charity Hospital during the years between 1834 and 1860. The Sisters of Charity of St. Joseph was founded in 1809 by Saint Elizabeth Ann Bailey Seton (first native-born North American canonized in 1975) in Emmitsburg, Maryland. Seton's Sisters of Charity was the first community for religious women to be established in the United States and was later incorporated with the French Daughters of Charity of St. Vincent de Paul in 1850. A call to work in New Orleans' Charity Hospital in the 1830s meant a significant achievement for the Sisters of Charity, since it was the second oldest continuously operating public hospitals in the United States until 2005, bearing the same name over the decades. In 1834, Sister Regina Smith and other sisters were officially called to Charity Hospital, in order to supersede the existing "nurses, attendants, and servants," and take a complete charge of the internal management of Charity Hospital. The existing scholarship on the history of hospitals and Catholic nursing has not integrated the concrete stories of the Sisters of Charity into the broader histories of institutionalized medicine, gender, and religion. Along with a variety of primary sources, this study primarily relies on the Charity Hospital History Folder stored at the Daughters of Charity West Center Province Archives. Located in the "Queen city of the South," Charity Hospital was the center of the southern medical profession and the world's fair of people and diseases. Charity Hospital provided the sisters with a unique situation that religion and medicine became intertwined. The Sisters, as nurses, constructed a new atmosphere of caring for patients and even their families inside and outside the hospital, and built their own separate space within the hospital walls. As hospital managers, the Sisters of Charity were put in complete charge of the hospital, which was never seen in other hospitals. By

Cytogenetic diagnosis of Roberts SC phocomelia syndrome: First report from Kashmir

OpenAIRE

Tahir M. Malla; Arshad A. Pandith; Fayaz A. Dar; Mahrukh H. Zargar

2016-01-01

There are several syndromes in which specific mitotic chromosomal abnormalities can be seen, like premature centromere separation, premature (sister) chromatid separation, and somatic aneuploidies. Identifications of such specific cytogenetic findings can be the key factor that leads towards the diagnosis of syndromes like Roberts SC phocomelia. The case presented here as Roberts SC phocomelia syndrome was identified as a child with multiple congenital anomalies and dysmorphic features. Conve...

Action of the poison of Apis mellifera bee and gamma radiation on bone marrow cells of Wistar rats and on lymphocytes of human peripheral blood

International Nuclear Information System (INIS)

Varanda, E.A.

1987-01-01

''In vivo'' and ''in vitro'' experiments are performed to determine the radioprotective action of the poison of Apis mellifera bees. The frequency of chromosome aberrations, induced by gamma radiation, is studied in two assays: ''in vivo'' in bone marrow cells from Wistar rats and ''in vitro'' in human peripheral blood lymphocyte cultures. The sister chromatid exchanges (SCE) are studied in the ''in vitro'' assays. (M.A.C.) [pt

Effect of cysteamine on sister chromatid exchange (SCE) induction by gamma rays

International Nuclear Information System (INIS)

Mendiola Cruz, M.T.

1987-01-01

The effect of different doses of cysteamine (3, 15 and 150 μg/g bw) on gamma ray-induced SCE was evaluated and compared with the responses obtained with regard to frequency of chromosomal aberrations, frequency of proliferating cells and the rate of cellular proliferating kinetics in mouse bone marrow cells in vivo. Groups of mice were either irradiated, treated with cysteamine and irradiated, only treated with cysteamine or left without treatment for determination of these parameters. The intraperitoneal administration of cysteamine preceding 1 Gy of gamma ray exposure, produces a dose dependent radioprotection on SCE-induction obtaining the greatest effect with 150 μg/g bw. However, this effect was not observed in the mitotic index nor in the average generation time. Chromosomic aberrations in animals irradiated after treatment with cysteamine were also detected. It was not observed any citotoxic or genotoxic effect produced by cysteamine per se. The results suggest that, under the experimental conditions of this study, the SCE are caused by free radicals produced by gamma radiation; not so, the additional damage indexes measured. (author)

Cohesion and device reliability in organic bulk heterojunction photovoltaic cells

KAUST Repository

Brand, Vitali

2012-04-01

The fracture resistance of P3HT:PC 60BM-based photovoltaic devices are characterized using quantitative adhesion and cohesion metrologies that allow identification of the weakest layer or interface in the device structure. We demonstrate that the phase separated bulk heterojunction layer is the weakest layer and report quantitative cohesion values which ranged from ∼1 to 20 J m -2. The effects of layer thickness, composition, and annealing treatments on layer cohesion are investigated. Using depth profiling and X-ray photoelectron spectroscopy on the resulting fracture surfaces, we examine the gradient of molecular components through the thickness of the bulk heterojunction layer. Finally, using atomic force microscopy we show how the topography of the failure path is related to buckling of the metal electrode and how it develops with annealing. The research provides new insights on how the molecular design, structure and composition affect the cohesive properties of organic photovoltaics. © 2011 Elsevier B.V. All rights reserved.

The territorial approach to EU cohesion policy: Current issues and evidence from Greece

Directory of Open Access Journals (Sweden)

Thoidou Elisavet

2011-01-01

Full Text Available The importance attributed to the territorial dimension of the European Union cohesion policy steadily influences its successive reforms and adaptations, while in recent years there has been an evolution in the way this particular dimension of cohesion policy is perceived. Important evidence for this is the way in which the Community Strategic Guidelines on cohesion 2007-13 take account of the territorial dimension of cohesion policy. This paper discusses the territorial approach to cohesion policy in relation to both policy and practice. Specifically, it examines the territorial dimension of regional development planning in Greece as it has emerged in the relevant official documents, namely the successive three Community Support Frameworks since 1989 and the National Strategic Reference Framework for the current 2007-13 period. The territorial dimension of the organization of the planning system is also considered in an effort to understand limitations and prospects, in light of the importance of the territorial approach to cohesion policy post-2013.

Group cohesion and starting status in successful and less successful elite volleyball teams.

Science.gov (United States)

Spink, K S

1992-08-01

The main purpose of this study was to examine the relationship between members' perceptions of group cohesion and starting status in elite volleyball teams. The results of the study revealed that the form of the cohesion-starting status relationship was moderated by the variable of success. The results for less successful teams revealed that differences did emerge between specific measures of cohesion endorsed by starters and non-starters. No such differences in cohesion emerged when the starters and non-starters on successful teams were compared. These results provide initial support for the suggestion that the most successful teams are the ones where the perceptions of cohesiveness by starters and non-starters are similar. A secondary purpose of the study was to determine whether those teams that were the most successful and similar in their members' perceptions of cohesiveness, were also the teams whose members have the most positive outcome expectancy. The results supported this prediction.

Effects of interface roughness on cohesive strength of self-assembled monolayers

Energy Technology Data Exchange (ETDEWEB)

Zhang, Chen [Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, IL 61801 (United States); Awasthi, Amnaya P. [Department of Mechanical and Aerospace Engineering, University of Florida, Gainesville, 32611 (United States); Geubelle, Philippe H., E-mail: geubelle@illinois.edu [Department of Aerospace Engineering, University of Illinois at Urbana-Champaign, IL 61801 (United States); Grady, Martha E.; Sottos, Nancy R. [Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, IL 61801 (United States)

2017-03-01

Highlights: • Self-assembled monolayer/transfer-printed gold interface modeled using continuum-level simulation. • Initial deformed film profile analyzed and instability assessed. • Effective cohesive response of SAM-enhanced interface extracted from spallation model. • Reduction of up to 70% cohesive strength of the interface from incorporation of roughness demonstrated. - Abstract: Self-assembled monolayers (SAMs) are aggregates of small molecular chains that have the property to form highly ordered assemblies. The choice of terminal groups on the chains makes them excellent contenders of molecular-level tailoring. Molecular dynamics (MD) simulations and experimental observations of spallation of two SAM-enhanced gold-film/silicon-substrate interfaces have shown that the cohesive strength of SAM-enriched transfer-printed interfaces is strongly dependent on the choice of terminal groups. Though the MD results of perfectly ordered atomistic surfaces show the same qualitative trend as the experiments, they over-predict the interfacial cohesive strengths by a factor of about 50. Results from AFM studies have revealed that the roughness of these interfaces is of the same order (∼1 nm) as the range of atomistic interactions. Hence, surface roughness is a key contributor in significantly reducing interfacial cohesive strength in these systems. In this manuscript, a continuum-level study is performed to investigate the influence of surface roughness on the cohesive strength of the interface between a Si/SAM substrate and a transfer-printed gold film. We approximate the film as a deformable continuum interacting with a rough substrate of SAMs represented by a harmonic function. Using a cohesive law derived from MD, spallation is simulated to evaluate the effective traction-separation characteristics for the rough SAM–gold interface. Our analysis shows that incorporating roughness may reduce the interfacial cohesive strength by an order of magnitude depending

Flocculation Dynamics of cohesive sediment

NARCIS (Netherlands)

Maggi, F.

2005-01-01

Cohesive sediment suspended in natural waters is subject not only to transport and deposition processes but also to reactions of flocculation, \\textit{i.e.} aggregation of fine particles, and breakup of aggregates. Although aggregation and breakup occur at small and very small length scales compared

Interactive Effects of Team Cohesion on Perceived Efficacy in Semi-Professional Sport

OpenAIRE

Marcos, Francisco Miguel Leo; Miguel, Pedro Antonio Sánchez; Oliva, David Sánchez; Calvo, Tomás García

2010-01-01

The present study examined the relationships among cohesion, self-efficacy, coaches’ perceptions of their players’ efficacy at the individual level and athletes’ perceptions of their teammates’ efficacy. Participants (n = 76) recruited from four semi- professional soccer and basketball teams completed cohesiveness and efficacy questionnaires who. Data were analyzed through a correlational methodology. Results indicated significant correlations between self-efficacy and task cohesion and socia...

Characterizing delamination of fibre composites by mixed mode cohesive laws

DEFF Research Database (Denmark)

Sørensen, Bent F.; Jacobsen, Torben K.

2009-01-01

A novel method is used for the determination of mixed mode cohesive laws and bridging laws for the characterisation of crack bridging in composites. The approach is based on an application of the J integral. The obtained cohesive laws were found to possess high peak stress values. Mixed mode...

Repairability during G1 of the inductor leisure of exchanges in the sister chromatid induced by alkylating agents in DNA substituted and no substituted with BUDR, in cells of the salivary gland of mouse In vivo; Reparabilidad durante G1 de las lesiones inductoras de intercambios en las cromatidas hermanas inducidos por agentes alquilantes en ADN sustituido y no sustituido con BrdU, en celulas de la glandula salival de raton In vivo

Energy Technology Data Exchange (ETDEWEB)

Gonzalez B, F

2004-07-01

In this work you determines the repair of the lesions inductoras of Sister chromatid exchange (ICHs) generated in the cells of the salivary gland of mouse, for the treatment with the N-Methyl-N-Nitrosourea (MNU), the N-Ethyl-N-Nitrosourea (ENU), the Methyl methanesulfonate (MMS) and the Ethyl methanesulfonate (EMS) in early and slow G1 of the first one and the second cellular division, that is to say before and after the cells incorporate 5-bromine-2 -Desoxyuridine (BrdU) in the DNA. Groups witness non treaties were included with mutagen. The cells of the salivary gland repaired the generated lesions partially by the MNU, the MMS and the EMS in the 1st division, and only the lesions induced by the ENU and MMS were repaired partially in the 2nd division. The ENU generates injure that they were not repaired in the 1st division and those taken place by the EMS were little repaired in the 2nd division. The methylating agents generated but ICHs that the ethylating. One observes that the BrdU makes to the molecule of the DNA but susceptible to the damage generated by the alkylating agents that induce the formation of the ICHs. This susceptibility was incremented around 150% for the treatment with the MNU, the ENU and the MMS, on the other hand for the EMS it was 3 times minor. It is proposed that the one electronegative atom of this analog of the timine would to work as a nucleophyllic center with which the electrophyllic compounds react. (Author)

Sisters in hereditary breast and ovarian cancer families: communal coping, social integration, and psychological well-being.

Science.gov (United States)

Koehly, Laura M; Peters, June A; Kuhn, Natalia; Hoskins, Lindsey; Letocha, Anne; Kenen, Regina; Loud, Jennifer; Greene, Mark H

2008-08-01

We investigated the association between psychological distress and indices of social integration and communal coping among sisters from hereditary breast and ovarian cancer (HBOC) families. Sixty-five sisters from 31 HBOC families completed the Brief Symptom Inventory-18 and the Colored Eco-Genetic Relationship Map, which identified members of participants' social support networks. Hierarchical linear models were used for all analyses to account for the clustering of sisters within families. Intra-family correlation coefficients suggested that sisters shared perceptions of breast cancer risk and worry, but not ovarian cancer risk and worry. Further, sisters demonstrated shared levels of anxiety and somatization, but not depressive symptoms. Communal coping indices quantifying shared support resources were negatively related to anxiety and somatization. The number of persons with whom cancer risk information was shared exhibited a positive trend with somatization. Social integration, as measured by the size of participants' emotional support network, was negatively associated with anxiety. Lower depression scores were observed among participants with more persons playing multiple support roles and fewer persons providing tangible assistance. Understanding how support relationships impact well-being among persons adjusting to HBOC risk, and the particular role of family in that process, will facilitate developing appropriate management approaches to help cancer-prone families adjust to their cancer risk.

Cohesion in a Multinational Coalition Center

National Research Council Canada - National Science Library

Schaab, Brooke

2007-01-01

.... All of the remaining nine items fell within the agree-to-strongly agree area. On interpersonal cohesion, highest agreement was found on items addressing the importance of liking and socializing with team members...

Mind the gap! Automated concept map feedback supports students in writing cohesive explanations.

Science.gov (United States)

Lachner, Andreas; Burkhart, Christian; Nückles, Matthias

2017-03-01

Many students are challenged with the demand of writing cohesive explanations. To support students in writing cohesive explanations, we developed a computer-based feedback tool that visualizes cohesion deficits of students' explanations in a concept map. We conducted three studies to investigate the effectiveness of such feedback as well as the underlying cognitive processes. In Study 1, we found that the concept map helped students identify potential cohesion gaps in their drafts and plan remedial revisions. In Study 2, students with concept map feedback conducted revisions that resulted in more locally and globally cohesive, and also more comprehensible, explanations than the explanations of students who revised without concept map feedback. In Study 3, we replicated the findings of Study 2 by and large. More importantly, students who had received concept map feedback on a training explanation 1 week later wrote a transfer explanation without feedback that was more cohesive than the explanation of students who had received no feedback on their training explanation. The automated concept map feedback appears to particularly support the evaluation phase of the revision process. Furthermore, the feedback enabled novice writers to acquire sustainable skills in writing cohesive explanations. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Relationship between the cohesion of guest particles on the flow behaviour of interactive mixtures.

Science.gov (United States)

Mangal, Sharad; Gengenbach, Thomas; Millington-Smith, Doug; Armstrong, Brian; Morton, David A V; Larson, Ian

2016-05-01

In this study, we aimed to investigate the effects cohesion of small surface-engineered guest binder particles on the flow behaviour of interactive mixtures. Polyvinylpyrrolidone (PVP) - a model pharmaceutical binder - was spray-dried with varying l-leucine feed concentrations to create small surface-engineered binder particles with varying cohesion. These spray-dried formulations were characterised by their particle size distribution, morphology and cohesion. Interactive mixtures were produced by blending these spray-dried formulations with paracetamol. The resultant blends were visualised under scanning electron microscope to confirm formation of interactive mixtures. Surface coverage of paracetamol by guest particles as well as the flow behaviour of these mixtures were examined. The flow performance of interactive mixtures was evaluated using measurements of conditioned bulk density, basic flowability energy, aeration energy and compressibility. With higher feed l-leucine concentrations, the surface roughness of small binder particles increased, while their cohesion decreased. Visual inspection of the SEM images of the blends indicated that the guest particles adhered to the surface of paracetamol resulting in effective formation of interactive mixtures. These images also showed that the low-cohesion guest particles were better de-agglomerated that consequently formed a more homogeneous interactive mixture with paracetamol compared with high-cohesion formulations. The flow performance of interactive mixtures changed as a function of the cohesion of the guest particles. Interactive mixtures with low-cohesion guest binder particles showed notably improved bulk flow performance compared with those containing high-cohesion guest binder particles. Thus, our study suggests that the cohesion of guest particles dictates the flow performance of interactive mixtures. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Termini of human chromosomes display elevated rates of mitotic recombination.

Science.gov (United States)

Cornforth, M N; Eberle, R L

2001-01-01

The strand-specific in situ hybridization technique of CO-FISH was used to probe telomeres of human mitotic cells in order to determine the spontaneous frequency of crossover. This approach allowed the detection of recombinational crossovers occurring anywhere along the length of individual chromosomes, including reciprocal events taking place between sister chromatids. Although the process of sister chromatid exchange (SCE) is the most prominent type of recombination in somatic mammalian cells, our results show that SCEs accounted for less than a third of the recombinational events revealed by CO-FISH. It is concluded that chromosomal regions near the termini of chromosome arms undergo extraordinarily high rates of spontaneous recombination, producing terminal crossovers whose small size precludes detection by standard cytogenetic methods. That similar results were observed for transformed epithelial cells, as well as primary fibroblasts, suggests that the phenomenon is a common characteristic of human cells. These findings are noteworthy because, although telomeric and subtelomeric DNA is known to be preferentially involved in certain types of recombination, the tips of somatic mammalian chromosomes have not previously been identified as preferred sites for crossover. Implications of these results are discussed in terms of limitations imposed on CO-FISH for its proposed use in directional hybridization mapping.

Social cohesion and social capital: Possible implications for the common good

Directory of Open Access Journals (Sweden)

Anita Cloete

2014-08-01

Full Text Available The main objective of the article is to identify the possible implications of social cohesion and social capital for the common good. In order to reach this overarching aim the following structure will be utilised. The first part explores the conceptual understanding of socialcohesion and social capital in order to establish how these concepts are related and how they could possibly inform each other. The contextual nature of social cohesion and social capital is briefly reflected upon, with specific reference to the South African context. The contribution of religious capital in the formation of social capital is explored in the last section of the article. The article could be viewed as mainly conceptual and explorative in nature in order to draw some conclusions about the common good of social capital and social cohesion.Intradisciplinary and/or interdisciplinary implications: This article contributes to the interdisciplinary discourse on social cohesion with specific reference to the role of congregations. It provides a critical reflection on the role of congregations with regard to bonding and bridging social capital. The contextual nature of social cohesion is also addressed with specific reference to South Africa.

Perceived Social Cohesion, Frequency of Going Out, and Depressive Symptoms in Older Adults

Directory of Open Access Journals (Sweden)

Namkee G. Choi PhD

2015-11-01

Full Text Available Objective: To examine both cross-sectional and longitudinal relationships between older adults’ perceptions of social cohesion in their community and depressive symptoms and the potential mediating effect of the frequency of going outside one’s home/building. Method: Using two waves (T1 and T2 of the National Health and Aging Trend Study ( n = 5,326, gender-stratified structural equation models were estimated to determine direct and indirect effects of perceived social cohesion on depressive symptoms. Results: At T1, both perceived cohesion and frequency of going out were directly associated with depressive symptoms; however, perceived cohesion predicted frequency of going out only for women. At T2, only frequency of going out was directly associated with depressive symptoms, although perceived cohesion predicted frequency of going out for both genders. T1 perceived cohesion did not predict T2 depressive symptoms. T1 depressive symptoms were the strongest predictor of T2 depressive symptoms. Conclusion: The findings underscore the importance of enhancing the social environment in promoting mental health in late life through active aging.

Structural quality of polyacrylamide-treated cohesive soils in the coastal tablelands of Pernambuco

Directory of Open Access Journals (Sweden)

Diego Vandeval Maranhão de Melo

2014-04-01

Full Text Available Water-soluble polymers are characterized as effective flocculating agents due to their molecular features. Their application to soils with horizons with structural problems, e.g, a cohesive character, contributes to improvements in the physical quality and thus to the agricultural suitability of such soils. The purpose of this study was to evaluate the structural quality of soils with cohesive horizons of coastal tablelands in the State of Pernambuco treated with polyacrylamide (PAM as chemical soil conditioner. To this end, three horizons (one cohesive and two non-cohesive of a Yellow Argisol (Ultisol were evaluated and to compare cohesive horizons, the horizon of a Yellow Latosol (Oxisol was selected. The treatments consisted of aqueous PAM solutions (12.5; 50.0; 100.0 mg kg-1 and distilled water (control. The structural aspects of the horizons were evaluated by the stability (soil mass retained in five diameter classes, aggregate distribution per size class (mean weight diameter- MWD, geometric mean diameter - GMD and the magnitude of the changes introduced by PAM by measuring the sensitivity index (Si. Aqueous PAM solutions increased aggregate stability in the largest evaluated diameter class of the cohesive and non-cohesive horizons, resulting in higher MWD and GMD, with highest efficiency of the 100 mg kg-1 solution. The cohesive horizon Bt1 in the Ultisol was most sensitive to the action of PAM, where highest Si values were found, but the structural quality of the BA horizon of the Oxisol was better in terms of stability and aggregate size distribution.

Childhood obsessive-compulsive traits in anorexia nervosa patients, their unaffected sisters and healthy controls: a retrospective study.

Science.gov (United States)

Degortes, Daniela; Zanetti, Tatiana; Tenconi, Elena; Santonastaso, Paolo; Favaro, Angela

2014-07-01

Although there is evidence that childhood perfectionistic traits predate the onset of eating disorders, few studies to date have examined the prevalence and clinical correlates of these traits in patients with anorexia nervosa (AN) and their unaffected sisters. The aim of this work was to study the prevalence of childhood obsessive-compulsive traits in patients with lifetime AN, their unaffected sisters and healthy women. A total of 116 AN patients, 32 healthy sisters and 119 controls were assessed by the EATATE Interview to assess traits such as perfectionism, inflexibility, rule-bound traits, drive for order and symmetry, and excessive doubt and cautiousness. Both self-report and maternal reports were collected. AN patients reported more childhood obsessive-compulsive traits than their healthy sisters and controls. In contrast, no differences between healthy controls and unaffected sisters emerged. In patients with AN, a dose-response relationship was found between the number of childhood obsessive-compulsive traits and psychopathology, including body image distortion, thus indicating that these traits are an important feature to be considered in assessing and treating eating disorders. Copyright © 2014 John Wiley & Sons, Ltd and Eating Disorders Association.

Influence of Sport Education on Group Cohesion in University Physical Education

Science.gov (United States)

Jenkins, Jayne M.; Alderman, Brandon L.

2011-01-01

The Sport Education ("SE") curricular model incorporated within university physical education Basic Instruction Program (BIP) may increase group cohesion. This study's purpose was to identify student perceptions of a BIP course taught within "SE," and investigate group cohesion in differing activity content. Participants…

Effects of Simultaneous Radiofrequency Radiation and Chemical Exposure of Mammalian Cells. Volume 2

Science.gov (United States)

1988-07-01

chromosome - - - - - - -I aberrations and sister chromatid exchanges (SCE). Yao (1982) exposed rat kangaroo RH5 and RH1l6 cells to 2.45 GHz radiation, and...control was reported in chromosome aberrations. Yac (1982) investigated the cytogenetic consequences of chronic microwave exposure on rat kangaroo RH5...was said to be 280C. The cells were exposed both as conidia, which are "rather inactive metabolically ," and also after DNA replication had been

Repair of O6-(2-chloroethyl)guanine mediates the biological effects of chloroethylnitrosoureas.

OpenAIRE

Bodell, W J; Aida, T; Berger, M S; Rosenblum, M L

1985-01-01

Chloroethylnitrosoureas (CENUs) are alkylating and crosslinking agents used for the treatment of human cancer; they are both mutagenic and carcinogenic. We compared the levels of induction of sister chromatid exchanges (SCEs) and the cytotoxicity of nitrosoureas that alkylate only with CENUs. CENUs are 200-fold more cytotoxic and induce SCEs with 45-fold greater efficiency than agents that do not crosslink; therefore, crosslinking is probably the most important molecular event that leads to c...

Imaging of DNA Ultrafine Bridges in Budding Yeast.

Science.gov (United States)

Quevedo, Oliver; Lisby, Michael

2018-01-01

DNA ultrafine bridges (UFBs) are a type of chromatin-free DNA bridges that connect sister chromatids in anaphase and pose a threat to genome stability. However, little is known about the origin of these structures, and how they are sensed and resolved by the cell. In this chapter, we review tools and methods for studying UFBs by fluorescence microscopy including chemical and genetic approaches to induce UFBs in the model organism Saccharomyces cerevisiae.

Imaging of DNA Ultrafine Bridges in Budding Yeast

DEFF Research Database (Denmark)

Quevedo Rodriguez, Oliver; Lisby, Michael

2018-01-01

DNA ultrafine bridges (UFBs) are a type of chromatin-free DNA bridges that connect sister chromatids in anaphase and pose a threat to genome stability. However, little is known about the origin of these structures, and how they are sensed and resolved by the cell. In this chapter, we review tools...... and methods for studying UFBs by fluorescence microscopy including chemical and genetic approaches to induce UFBs in the model organism Saccharomyces cerevisiae....

DNA template strand sequencing of single-cells maps genomic rearrangements at high resolution

OpenAIRE

Falconer, Ester; Hills, Mark; Naumann, Ulrike; Poon, Steven S. S.; Chavez, Elizabeth A.; Sanders, Ashley D.; Zhao, Yongjun; Hirst, Martin; Lansdorp, Peter M.

2012-01-01

DNA rearrangements such as sister chromatid exchanges (SCEs) are sensitive indicators of genomic stress and instability, but they are typically masked by single-cell sequencing techniques. We developed Strand-seq to independently sequence parental DNA template strands from single cells, making it possible to map SCEs at orders-of-magnitude greater resolution than was previously possible. On average, murine embryonic stem (mES) cells exhibit eight SCEs, which are detected at a resolution of up...

Synthesis and SAR studies of 5-(pyridin-4-yl)-1,3,4-thiadiazol-2-amine derivatives as potent inhibitors of Bloom helicase

DEFF Research Database (Denmark)

Rosenthal, Andrew S; Dexheimer, Thomas S; Gileadi, Opher

2013-01-01

complementary strands of duplex DNA as well as atypical DNA structures such as Holliday junctions. Mutations of the BLM gene can result in Bloom syndrome, an autosomal recessive disorder associated with cancer predisposition. BLM-deficient cells exhibit increased sensitivity to DNA damaging agents indicating...... and related analogs, which possess potent BLM inhibition and exhibit selectivity over related helicases. Moreover, these compounds demonstrated cellular activity by inducing sister chromatid exchanges, a hallmark of Bloom syndrome....

In vitro studies on chemoprotective effect of Purnark against benzo(a)pyrene-induced chromosomal damage in human lymphocytes.

Science.gov (United States)

Ghaisas, S D; Bhide, S V

1994-01-01

Human lymphocytes were used as an assay system to test chemopreventive activity of natural products. Purnark, a mixture of extracts of turmeric, betel leaf and catechu, was tested for its chemoprotective activity against BP induced DNA damage. Sister chromatid exchange and micronuclei were used as markers to assess the protective activity of Purnark. Purnark gave 50-60% protection against BP induced SCEs and micronuclei. Purnark at 100 micrograms dose did not show any genotoxicity.

Inhibition of repair activity induced by γ-radiation, UV-rays and radiomimetics in the in vitro cultured cells of patients wiyh schizophrenia

International Nuclear Information System (INIS)

Zasukhina, G.D.; Zharikov, N.M.; L'vova, G.N.; Vasil'eva, I.M.; Chekova, V.V.; Alekhina, N.I.; Ivanova, T.N.

1986-01-01

A study was made of the processes of repair, virus reactivation, and formation of sister chromatid exchages (SCE) in blood cells of patients with schizophrenia after the effect of γ-radiation and 4-nitroquinoline-1-oxide. These processes were estimated by 12 criteria. The mutagen-induced disturbances in the processes of repair and SCE formation were found in cells of patients with schizophrenia and were absent in the control cells of healthy donors

Family cohesion, acculturation, maternal cortisol, and preterm birth in Mexican-American women

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Ruiz RJ

2013-05-01

Full Text Available R Jeanne Ruiz,1 Rita H Pickler,2 C Nathan Marti,3 Nancy Jallo41College of Nursing, The Ohio State University, Columbus, OH, USA; 2Department of Patient Services, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA; 3Abacist Analytics, Austin, TX, USA; 4School of Nursing, Virginia Commonwealth University, Richmond, VA, USAObjective: To examine the potential moderating effects of family cohesion and acculturation on the physiological stress response (cortisol as a predictor of preterm birth (PTB in pregnant Mexican-American women.Methods: The sample included 470 participants; 33 had preterm births. All participants were self-identified as Mexican-American. In this cross-sectional study, family cohesion was measured by a self-report questionnaire. Acculturation was measured by self-report questionnaire as well as by years in the United States and country of birth. Stress was measured by serum cortisol. All measures were obtained at 22—24 weeks gestation. Additional data including history of PTB were obtained from the health record. Data analysis was primarily conducted using logistic regression.Results: The relationship between stress and PTB was predicted by family cohesion (estimate/standard error [E/SE] = —2.46, P = 0.014 and acculturation (E/SE = 2.56, P = 0.011. In addition, there was an interaction between family cohesion and history of previous PTB (E/SE = —2.12, P = 0.035.Conclusion: Results indicate that the impact of cortisol on PTB is predicted by acculturation and family cohesion such that higher levels of cortisol in conjunction with higher levels of acculturation and lower levels of family cohesion are associated with increased risk of PTB. In addition, low family cohesion in combination with a history of PTB was associated with higher levels of PTB. Assessment of family cohesion, including problem solving, adherence to family decisions, family shared space, and activity, should be included as part of prenatal

Development of low energy electron beam irradiation technology. Application to cohesive and adhesive agents

International Nuclear Information System (INIS)

Ito, Hisashi; Enomoto, Ichiro; Tsuchiya, Mitsuaki

1996-01-01

The hightening of the cohesive and adhesive performances of rubber cohesive and adhesive agents, of which the main component is electron beam-cross-linked styrene-isoprene block copolymer (SIS), was tried. Cohesive and adhesive agents are cohesive agents at the time of use, but change to adhesive property by the lapse of time or the means using heat, light or radiation, and further, partially to separating property. This time, as a cohesion-giving agent, ARKON P-100 system was examined, and the heightening of adhesive performance including the improvement of the heat resistance and solvent endurance, which are the demerits of rubber, was investigated. Also the difference of the cohesive and adhesive performances due to the kinds of cohesion-giving agents was examined. The samples were prepared by irradiating the films on which the SIS was applied. The measurement of gel proportion, the holding force test at elevated temperature, the measurement of DSC and 180deg separation test were carried out. Respective testing methods and the results are reported. By electron beam irradiation, the heat resistance and solvent endurance were improved without affecting the separation force. (K.I.)

Group cohesion in foraging meerkats: follow the moving 'vocal hot spot'.

Science.gov (United States)

Gall, Gabriella E C; Manser, Marta B

2017-04-01

Group coordination, when 'on the move' or when visibility is low, is a challenge faced by many social living animals. While some animals manage to maintain cohesion solely through visual contact, the mechanism of group cohesion through other modes of communication, a necessity when visual contact is reduced, is not yet understood. Meerkats ( Suricata suricatta ), a small, social carnivore, forage as a cohesive group while moving continuously. While foraging, they frequently emit 'close calls', soft close-range contact calls. Variations in their call rates based on their local environment, coupled with individual movement, produce a dynamic acoustic landscape with a moving 'vocal hotspot' of the highest calling activity. We investigated whether meerkats follow such a vocal hotspot by playing back close calls of multiple individuals to foraging meerkats from the front and back edge of the group simultaneously. These two artificially induced vocal hotspots caused the group to spatially elongate and split into two subgroups. We conclude that meerkats use the emergent dynamic call pattern of the group to adjust their movement direction and maintain cohesion. Our study describes a highly flexible mechanism for the maintenance of group cohesion through vocal communication, for mobile species in habitats with low visibility and where movement decisions need to be adjusted continuously to changing environmental conditions.

Analysis of cohesion and collective efficacy profiles for the performance of soccer players.

Science.gov (United States)

Leo, Francisco M; Sánchez-Miguel, Pedro A; Sánchez-Oliva, David; Amado, Diana; García-Calvo, Tomás

2013-12-18

The principal aims of the study were to define different profiles of cohesion and perceived efficacy in soccer players and to measure their differences in performance. The subjects were 235 soccer players in the under-18 category who played in the National League in Spain and 15 coaches whose ages ranged from 29 to 45 years. Diverse instruments to assess cohesion, perceived efficacy, and expectations of success were used in the study. Moreover, we measured playing time and performance. The results of the study proved the existence of four cohesion and efficacy profiles that presented significant differences in expectations of success, playing time, and performance. Furthermore, significant differences were found in the distribution of players in the teams as a function of performance. The main conclusion of this study is that soccer players with higher cohesion and collective efficacy levels belonged to teams that completed the season at the top-level classification. In contrast, athletes with low cohesion and collective efficacy usually played in unsuccessful teams. Coaches and sports psychologists are encouraged to promote both social and task cohesion and collective efficacy to enhance team performance.

Mode I Cohesive Law Characterization of Through-Crack Propagation in a Multidirectional Laminate

Science.gov (United States)

Bergan, Andrew C.; Davila, Carlos G.; Leone, Frank A.; Awerbuch, Jonathan; Tan, Tein-Min

2014-01-01

A method is proposed and assessed for the experimental characterization of through-the-thickness crack propagation in multidirectional composite laminates with a cohesive law. The fracture toughness and crack opening displacement are measured and used to determine a cohesive law. Two methods of computing fracture toughness are assessed and compared. While previously proposed cohesive characterizations based on the R-curve exhibit size effects, the proposed approach results in a cohesive law that is a material property. The compact tension specimen configuration is used to propagate damage while load and full-field displacements are recorded. These measurements are used to compute the fracture toughness and crack opening displacement from which the cohesive law is characterized. The experimental results show that a steady-state fracture toughness is not reached. However, the proposed method extrapolates to steady-state and is demonstrated capable of predicting the structural behavior of geometrically-scaled specimens.

An illness in the family: Dr. Maude Abbott and her sister, Alice Abbott.

Science.gov (United States)

Brookes, Barbara

2011-01-01

This paper explores Maude Abbott's internationally significant career in medicine and her parallel commitment to caring for her sister, Alice Abbott. An examination of Abbott's life reveals the difficulties faced by an ambitious Canadian woman in medicine from the 1890s to the 1920s; difficulties compounded by caring for a sister with a mental illness. The Abbott archive suggests that it was far more difficult for a woman doctor to make the kind of sharp distinction between public and private life that might be expected of professional men.

Sister chromosome pairing maintains heterozygosity in parthenogenetic lizards.

Science.gov (United States)

Lutes, Aracely A; Neaves, William B; Baumann, Diana P; Wiegraebe, Winfried; Baumann, Peter

2010-03-11

Although bisexual reproduction has proven to be highly successful, parthenogenetic all-female populations occur frequently in certain taxa, including the whiptail lizards of the genus Aspidoscelis. Allozyme analysis revealed a high degree of fixed heterozygosity in these parthenogenetic species, supporting the view that they originated from hybridization events between related sexual species. It has remained unclear how the meiotic program is altered to produce diploid eggs while maintaining heterozygosity. Here we show that meiosis commences with twice the number of chromosomes in parthenogenetic versus sexual species, a mechanism that provides the basis for generating gametes with unreduced chromosome content without fundamental deviation from the classic meiotic program. Our observation of synaptonemal complexes and chiasmata demonstrate that a typical meiotic program occurs and that heterozygosity is not maintained by bypassing recombination. Instead, fluorescent in situ hybridization probes that distinguish between homologues reveal that bivalents form between sister chromosomes, the genetically identical products of the first of two premeiotic replication cycles. Sister chromosome pairing provides a mechanism for the maintenance of heterozygosity, which is critical for offsetting the reduced fitness associated with the lack of genetic diversity in parthenogenetic species.

Umbilical metastasis (Sister Mary Joseph's nodule diagnosed by fine-needle aspiration

Directory of Open Access Journals (Sweden)

Tatomirović Željka

2004-01-01

Full Text Available Sister Mary Joseph’s nodule is the eponym for metastatic involvement of the umbilicus. This less common entity is the sign of disseminated malignant disease, mainly of digestive and gynecologic origin, and is associated with a poor prognosis. A case of Sister Mary Joseph’s nodule in a 76-year-old woman in whom the umbilical metastasis was the first sign of malignant disease in presented. The diagnosis of metastatic adenocarcinoma was established by fine needle aspiration cytology of the umbilical nodule. Radiological and ultrasonographic investigation disclosed carcinoma of the gallbladder with pancreas, stomach, and colon invasion as well as peritoneal dissemination. The diagnosis was confirmed by exploratory laparatomy and histological examination of the excised umbilical nodule.

The Lehman Sisters Hypothesis: an exploration of literature and bankers

NARCIS (Netherlands)

I.P. van Staveren (Irene)

2012-01-01

textabstractAbstract This article tests the Lehman Sisters Hypothesis in two complementary, although incomplete ways. It reviews the diverse empirical literature in behavioral, experimental, and neuroeconomics as well as related fields of behavioral research. And it presents the findings from an

The Lehman Sisters Hypothesis: an exploration of literature and bankers

NARCIS (Netherlands)

I.P. van Staveren (Irene)

2012-01-01

textabstractThis article tests the Lehman Sisters Hypothesis in two complementary, although incomplete ways. It reviews the diverse empirical literature in behavioural, experimental, and neuroeconomics as well as related fields of behavioural research. And it presents the findings from an

Extensive range overlap between heliconiine sister species: evidence for sympatric speciation in butterflies?

Science.gov (United States)

Rosser, Neil; Kozak, Krzysztof M; Phillimore, Albert B; Mallet, James

2015-06-30

Sympatric speciation is today generally viewed as plausible, and some well-supported examples exist, but its relative contribution to biodiversity remains to be established. We here quantify geographic overlap of sister species of heliconiine butterflies, and use age-range correlations and spatial simulations of the geography of speciation to infer the frequency of sympatric speciation. We also test whether shifts in mimetic wing colour pattern, host plant use and climate niche play a role in speciation, and whether such shifts are associated with sympatry. Approximately a third of all heliconiine sister species pairs exhibit near complete range overlap, and analyses of the observed patterns of range overlap suggest that sympatric speciation contributes 32%-95% of speciation events. Müllerian mimicry colour patterns and host plant choice are highly labile traits that seem to be associated with speciation, but we find no association between shifts in these traits and range overlap. In contrast, climatic niches of sister species are more conserved. Unlike birds and mammals, sister species of heliconiines are often sympatric and our inferences using the most recent comparative methods suggest that sympatric speciation is common. However, if sister species spread rapidly into sympatry (e.g. due to their similar climatic niches), then assumptions underlying our methods would be violated. Furthermore, although we find some evidence for the role of ecology in speciation, ecological shifts did not show the associations with range overlap expected under sympatric speciation. We delimit species of heliconiines in three different ways, based on "strict and " "relaxed" biological species concepts (BSC), as well as on a surrogate for the widely-used "diagnostic" version of the phylogenetic species concept (PSC). We show that one reason why more sympatric speciation is inferred in heliconiines than in birds may be due to a different culture of species delimitation in the two

Ukrainian and European Baroque in the Context of “Sister Arts” Idea

Directory of Open Access Journals (Sweden)

Olga Shikirinskaya

2015-08-01

Full Text Available The article deals with the “Sister Arts” tradition as the interrelationship of various art forms (poetry, fiction, painting, theatre, music etc. relative to the Baroque period. “Sister Arts” criticism, based on E.G. Lessing essay “Laocoön…” uses the inter-art analogies to appreciate the importance of literature in the Arts, as well as to comprehend aspects of the modern approach to the synthesis of the arts. The article presents the aesthetic concept of Baroque art and its realization in architecture, sculpture, decorative and applied arts, music and literature on the background of the European and Ukrainian cultural tradition.

Cohesive zone modeling of intergranular cracking in polycrystalline aggregates

International Nuclear Information System (INIS)

Simonovski, Igor; Cizelj, Leon

2015-01-01

Highlights: • Alternative approach to cohesive elements is proposed: cohesive-zone contact. • Applicability to measured and simulated grain structures is demonstrated. • Normal and normal/shear separation as a damage initialization is explored. • Normal/shear damage initialization significantly reduces ductility. • Little difference in Voronoi aggregate size on macroscopic response. - Abstract: Understanding and controlling early damage initiation and evolution are amongst the most important challenges in nuclear power plants, occurring in ferritic, austenitic steels and nickel based alloys. In this work a meso-scale approach to modeling initiation and evolution of early intergranular cracking is presented. This damage mechanism is present in a number of nuclear power plant components and depends on the material (e.g. composition, heat treatment, microstructure), environment and load. Finite element modeling is used to explicitly model the microstructure – both the grains and the grain boundaries. Spatial Voronoi tessellation is used to obtain the grain topology. In addition, measured topology of a 0.4 mm stainless steel wire is used. Anisotropic elasticity and crystal plasticity are used as constitutive laws for the grains. Grain boundaries are modeled using the cohesive zone approach. Different modeling assumptions/parameters are evaluated against the numerical stability criteria. The biggest positive contribution to numerical stability is the use of cohesive-type contact instead of cohesive elements. A small amount of viscous regularization should be also used along with the addition of a small amount of viscous forces to the global equilibrium equations. Two cases of grain boundary damage initiation are explored: (1) initiation due to normal separation and (2) initiation due to a combination of normal and shear separation. The second criterion significantly decreases the ductility of an aggregate and slightly improves the numerical stability

The Effects Of Physical And Biological Cohesion On Bedforms

Science.gov (United States)

Parsons, D. R.; Schindler, R.; Baas, J.; Hope, J. A.; Malarkey, J.; Paterson, D. M.; Peakall, J.; Manning, A. J.; Ye, L.; Aspden, R.; Alan, D.; Bass, S. J.

2014-12-01

Most coastal sediments consist of complex mixtures of cohesionless sands, physically-cohesive clays and extra cellular polymeric substances (EPS) that impart biological cohesion. Yet, our ability to predict bedform dimensions in these substrates is reliant on predictions based exclusively on cohesionless sand. We present findings from the COHBED project - which explicitly examines how bedform dynamics are modified by natural cohesion. Our experimental results show that for ripples, height and length are inversely proportional to initial clay content and bedforms take longer to appear, with no ripples when clay content exceeds 18%. When clay is replaced by EPS the development time and time of first appearance of ripples both increase by two orders of magnitude, with no bedforms above 0.125% EPS. For dunes, height and length are also inversely proportional to initial substrate clay content, resulting in a transition from dunes to ripples normally associated with velocity decreases. Addition of low EPS concentrations into the substrate results in yet smaller bedforms at the same clay contents and at high EPS concentrations, biological cohesion supersedes all electrostatic bonding, and bedform size is no longer related to mud content. The contrast in physical and biological cohesion effects on bedform development result from the disparity between inter-particle electrostatic bonding of clay particles and EPS grain coating and strands that physically link sediments together, which effects winnowing rates as bedforms evolve. These findings have wide ranging implications for bedform predictions in both modern and ancient environments. Coupling of biological and morphological processes not only requires an understanding of how bedform dimensions influence biota and habitat, but also how benthic species can modify bedform dimensions. Consideration of both aspects provides a means in which fluid dynamics, sediment transport and ecosystem energetics can be linked to yield

Interrelations between Energy Security Economics and Social Cohesion: Analysis of a Lithuanian Case

Directory of Open Access Journals (Sweden)

Dainius Genys

2015-12-01

Full Text Available Growing attention to sustainable development in academic discourse fosters discussions on how energy security affects society. In most cases the discussions consider the political and economic consequences, which affect or may affect the society. The aim of the article is to assess the impact of energy security economics on social cohesion in Lithuania. To achieve this aim the interrelations between energy security, energy economics and social cohesion are discussed. The theoretical framework of social cohesion (introduced by J. Jenson and P. Bernard is presented and applied in empirical analysis. The operationalization of empirical variables is based on economic, political and socio-cultural - activity areas, which are analyzed to verify the dichotomies between public attitudes and the actual behavior of society. These dichotomies help to distinguish six analytical dimensions, on the basis of which we created 17 empirical indicators, which analysis allows for describing the impact of Lithuanian energy security economics on social cohesion in quantitative data. The statistical analyses showed that the impact of attitudinal dimensions of energy security economics on social cohesion in Lithuania has an almost neutral effect: 3.05 (1-very negative; 3-neutral, 5-very positive. Whereas, the impact of behavioural dimensions of energy security economics on social cohesion has a negative effect: 2.47. The aggregated average of the overall impact of energy security economics on social cohesion in Lithuania has a negative effect: 2.76.

Validating Experimental Bedform Dynamics on Cohesive Sand-Mud Beds in the Dee Estuary

Science.gov (United States)

Baas, Jaco H.; Baker, Megan; Hope, Julie; Malarkey, Jonathan; Rocha, Renata

2014-05-01

Recent laboratory experiments and field measurements have shown that small quantities of cohesive clay, and in particular 'sticky' biological polymers, within a sandy substrate dramatically reduce the development rate of sedimentary bedforms, with major implications for sediment transport rate calculations and process interpretations from the sedimentary record. FURTHER INFORMATION Flow and sediment transport predictions from sedimentary structures found in modern estuaries and within estuarine geological systems are impeded by an almost complete lack of process-based knowledge of the behaviour of natural sediments that consist of mixtures of cohesionless sand and biologically-active cohesive mud. Indeed, existing predictive models are largely based on non-organic cohesionless sands, despite the fact that mud, in pure form or mixed with sand, is the most common sediment on Earth and also the most biologically active interface across a range of Earth-surface environments, including rivers and shallow seas. The multidisciplinary COHBED project uses state-of-the-art laboratory and field technologies to measure the erosional properties of mixed cohesive sediment beds and the formation and stability of sedimentary bedforms on these beds, integrating the key physical and biological processes that govern bed evolution. The development of current ripples on cohesive mixed sediment beds was investigated as a function of physical control on bed cohesion versus biological control on bed cohesion. These investigations included laboratory flume experiments in the Hydrodynamics Laboratory (Bangor University) and field experiments in the Dee estuary (at West Kirby near Liverpool). The flume experiments showed that winnowing of fine-grained cohesive sediment, including biological stabilisers, is an important process affecting the development rate, size and shape of the cohesive bedforms. The ripples developed progressively slower as the kaolin clay fraction in the sandy substrate

Cohesion Features in ESL Reading: Comparing Beginning, Intermediate and Advanced Textbooks

Science.gov (United States)

Plakans, Lia; Bilki, Zeynep

2016-01-01

This study of English as a second language (ESL) reading textbooks investigates cohesion in reading passages from 27 textbooks. The guiding research questions were whether and how cohesion differs across textbooks written for beginning, intermediate, and advanced second language readers. Using a computational tool called Coh-Metrix, textual…

Fatigue damage modeling in solder interconnects using a cohesive zone approach

NARCIS (Netherlands)

Abdul-Baqi, A.J.J.; Schreurs, P.J.G.; Geers, M.G.D.

2005-01-01

The objective of this work is to model the fatigue damage process in a solder bump subjected to cyclic loading conditions. Fatigue damage is simulated using the cohesive zone methodology. Damage is assumed to occur at interfaces modeled through cohesive zones in the material, while the bulk material

Cohesion, leadership, mental health stigmatisation and perceived barriers to care in UK military personnel.

Science.gov (United States)

Jones, Norman; Campion, Ben; Keeling, Mary; Greenberg, Neil

2018-02-01

Military research suggests a significant association between leadership, cohesion, mental health stigmatisation and perceived barriers to care (stigma/BTC). Most studies are cross sectional, therefore longitudinal data were used to examine the association of leadership and cohesion with stigma/BTC. Military personnel provided measures of leadership, cohesion, stigma/BTC, mental health awareness and willingness to discuss mental health following deployment (n = 2510) and 4-6 months later (n = 1636). At follow-up, baseline leadership and cohesion were significantly associated with stigma/BTC; baseline cohesion alone was significantly associated with awareness of and willingness to discuss mental health at follow-up. Over time, changes in perceived leadership and cohesion were significantly associated with corresponding changes in stigma/BTC levels. Stigma/BTC content was similar in both surveys; fear of being viewed as weak and being treated differently by leaders was most frequently endorsed while thinking less of a help-seeking team member and unawareness of potential help sources were least common. Effective leadership and cohesion building may help to reduce stigma/BTC in military personnel. Mental health awareness and promoting the discussion of mental health matters may represent core elements of supportive leader behaviour. Perceptions of weakness and fears of being treated differently represent a focus for stigma/BTC reduction.

Social cohesion and the smoking behaviors of adults living with children.

Science.gov (United States)

Alcalá, Héctor E; Sharif, Mienah Z; Albert, Stephanie L

2016-02-01

The smoking behavior of adults can negatively impact children through exposure to environmental tobacco smoke and by modeling this unhealthy behavior. Little research has examined the role of the social environment in smoking behaviors of adults living with children. The present study specifically analyzed the relationship between social cohesion and smoking behaviors of adults living with children. Data from the 2009 California Health Interview Survey, a random-digit dial cross-sectional survey of California Adults, were used. Adults living with children reported their levels of social cohesion and smoking behaviors (N=13,978). Logistic regression models were used to predict odds of being a current smoker or living in a household in which smoking was allowed, from social cohesion. Overall, 13% of the sample was current smokers and 3.74% lived in households in which smoking was allowed. Logistic regression models showed that each one-unit increase in social cohesion is associated with reduced odds of being a current smoker (AOR=0.92; 95% CI=0.85-0.99) and reduced odds of living in a household in which smoking is allowed (AOR=0.84; 95% CI=0.75-0.93), after controlling for sociodemographic characteristics. Among adults living with children, higher social cohesion is associated with a lower likelihood of both being and smoker and living in a home where smoking is allowed. Thus, future research is needed to better understand mechanisms that explain the relationship between social cohesion and smoking-related behavior in order to prevent smoking-related health consequences and smoking initiation among children and adults. Copyright © 2015 Elsevier Ltd. All rights reserved.

Place-based innovation in Cohesion Policy: meeting and measuring the challenges

Directory of Open Access Journals (Sweden)

Alys Solly

2016-01-01

Full Text Available This paper, prepared in conjunction with the European Union’s Open Days 2015, examines current Cohesion Policy in terms of its place-based logic, a key aspect of the new Smart Specialisation strategy platform. After discussing changing notions of urbanization and governance, which seem to be shifting Cohesion Policy towards a more performance-oriented analysis of its outcomes, the paper focuses on the question of identifying an appropriate set of indicators and measuring framework. It suggests that measurements of Cohesion Policy performance should analyse the outcomes and indicators, as well as the European and national data sources and statistics, through the lens of effectiveness and well-being.

Sister chromatoid exchanges in atomic bomb survivors

International Nuclear Information System (INIS)

Nakano, Mimako; Awa, Akio

1980-01-01

Sister chromatoid exchange (SCE) frequencies in the peripheral lymphocyte with and without mitomycin-C (MMC) were studied, in the age of tens and thirties for an atomic-bomb survivor group and in thirties, fifties, and seventies for an unexposed group. The observation of 100 cells showed no statistically significant difference of SCE frequencies with aging or irradiation. The increasing rates of SCE frequencies by MMC showed no difference among the groups. The average increasing ratio by MMC was 3.6. (Nakanishi, T.)

Cohesion and Trauma: An Examination of a Collegiate Women's Volleyball Team

Science.gov (United States)

Fletcher, Teresa B.; Meyer, Barbara B.

2009-01-01

This study examined the effects of Adventure Based Counseling (i.e., a low-element challenge program) on the cohesion of a collegiate women's volleyball team. Results suggest postintervention improvements in team cohesion. The support created in the challenge experience also transferred to the players helping one another to grieve the untimely…

Development of a cohesion questionnaire for youth: the Youth Sport Environment Questionnaire.

Science.gov (United States)

Eys, Mark; Loughead, Todd; Bray, Steven R; Carron, Albert V

2009-06-01

The purpose of the current study was to initiate the development of a psychometrically sound measure of cohesion for youth sport groups. A series of projects were undertaken in a four-phase research program. The initial phase was designed to garner an understanding of how youth sport group members perceived the concept of cohesion through focus groups (n = 56), open-ended questionnaires (n = 280), and a literature review. In Phase 2, information from the initial projects was used in the development of 142 potential items and content validity was assessed. In Phase 3, 227 participants completed a revised 87-item questionnaire. Principal components analyses further reduced the number of items to 17 and suggested a two-factor structure (i.e., task and social cohesion dimensions). Finally, support for the factorial validity of the resultant questionnaire was provided through confirmatory factor analyses with an independent sample (n = 352) in Phase 4. The final version of the questionnaire contains 16 items that assess task and social cohesion in addition to 2 negatively worded spurious items. Specific issues related to assessing youth perceptions of cohesion are discussed and future research directions are suggested.

High frequencies of chromatid aberrations produced during G/sub 2/ in human lymphocytes by very low doses (0. 025-0. 4 Gy) of X-rays in combination with inhibitors of DNA synthesis

Energy Technology Data Exchange (ETDEWEB)

Andersson, H.C.; Kihlman, B.A. (Uppsala Univ. (Sweden). Dept. of Genetics)

1984-09-01

Whole-blood cultures of human lymphocytes were exposed in the G/sub 2/-phase (3.5 h before harvesting) to various doses of X-rays and post-treated for 3 h with inhibitors of DNA synthesis. The inhibitors used were 2'-deoxyadenosine (dAdo), hydroxyurea (HU) and 1-..beta..-D-arabinofuranosylcytosine (ara-C). To prevent deamination of dAdo by adenosine deaminase (ADA), the dAdo treatments were carried out in the presence of the ADA inhibitor coformycin. HU and ara-C were used either alone or in combination. After the 3-h inhibitor treatments, the cultures were harvested and slides prepared and analyzed for chromatid aberrations in metaphase. When the inhibitors were used at concentrations high enough to cause marked chromosome damage by themselves, very low doses of X-rays (0.025-0.2 Gy) were sufficient to produce a dramatic increase in the frequency of chromatid aberrations. High frequencies of chromatid aberrations were also obtained when cultures that had received moderate doses of X-rays (0.4-0.8 Gy) were post-treated with low inhibitor concentrations that produce no or only a few aberrations by themselves.

Investigating the relationship between leader behaviours and group cohesion within women's walking groups.

Science.gov (United States)

Caperchione, Cristina; Mummery, W Kerry; Duncan, Mitch

2011-07-01

Early research has shown that leadership behaviour is viewed as a crucial factor in successfully developing team cohesion, effectively resulting in greater team satisfaction and more positive team outcomes. However, little is understood if these same factors have an impact on physical activity groups. The purpose of this study was to investigate the relationship between leader behaviours and group cohesiveness within women's physical activity groups. Participants (N = 95) included a sub-sample of adult women who were previously involved in a women's physical activity/walking program. Participants assessed their groups' leader behaviour using items pertaining to enthusiasm, motivation, instruction and availability, and their groups' cohesiveness using the Physical Activity Group Environment Questionnaire (PAGEQ). Canonical correlation analysis was used to determine the strength of association between the four concepts of group cohesion (ATG-T, ATG-S, GI-T and GI-S) and the four items pertaining to leadership behaviour. A significant multivariate relationship was revealed between group cohesion and leadership behaviour, Wilks' lambda = 0.43, F(16,170) = 5.16, p cohesion. Although a cause-effect relationship cannot be determined, the current study can serve as a valuable template in guiding future research in examining potential mechanisms that may assist with physical activity sustainability. Crown Copyright © 2011. Published by Elsevier Ltd. All rights reserved.

The development of SisterTalk: a cable TV-delivered weight control program for black women.

Science.gov (United States)

Gans, Kim M; Kumanyika, Shiriki K; Lovell, H Joan; Risica, Patricia M; Goldman, Roberta; Odoms-Young, Angela; Strolla, Leslie O; Decaille, Donna O; Caron, Colleen; Lasater, Thomas M

2003-12-01

Overweight and obesity have reached epidemic proportions in the United States, with black women disproportionately affected. SisterTalk is a weight control program designed specifically for delivery to black women via cable TV. The theoretical and conceptual frameworks and formative research that guided the development and cultural tailoring of SisterTalk are described. Social Action Theory was applied in the development of SisterTalk along with a detailed behavioral analysis of the way that black women view weight and weight loss within the context of their cultural and social realities. The entire intervention development process was framed using this information, rather than by changing only superficial aspects of program delivery. Community networking and both qualitative and quantitative interview techniques from the fields of social marketing and cultural anthropology were used to involve black women from Boston in the design and implementation of a program that would be practical, appealing, and culturally sensitive. Also discussed are strategies for evaluating the program, and lessons learned that might have broader applicability are highlighted. The development of the SisterTalk program could provide a useful starting point for development of successful weight control programs for black women in other parts of the United States as well as for other ethnic and racial groups.

Many functions of the meiotic cohesin.

Science.gov (United States)

Bardhan, Amit

2010-12-01

Sister chromatids are held together from the time of their formation in S phase until they segregate in anaphase by the cohesin complex. In meiosis of most organisms, the mitotic Mcd1/Scc1/Rad21 subunit of the cohesin complex is largely replaced by its paralog named Rec8. This article reviews the specialized functions of Rec8 that are crucial for diverse aspects of chromosome dynamics in meiosis, and presents some speculations relating to meiotic chromosome organization.

In Vivo Cytogenetic Studies on Aspartame

OpenAIRE

AlSuhaibani, Entissar S.

2010-01-01

Aspartame (a-Laspartyl-L-phenylalanine 1-methylester) is a dipeptide low-calorie artificial sweetener that is widely used as a nonnutritive sweetener in foods and drinks. The safety of aspartame and its metabolic breakdown products (phenylalanine, aspartic acid and methanol) was investigated in vivo using chromosomal aberration (CA) test and sister chromatid exchange (SCE) test in the bone marrow cells of mice. Swiss Albino male mice were exposed to aspartame (3.5, 35, 350 mg/kg body weight)....

Group cohesion in sports teams of different professional level

OpenAIRE

Vazha M. Devishvili; Marina O. Mdivani; Daria S. Elgina

2017-01-01

Background. Team sports are not only the most exciting sporting events. but also complex activities that make serious demands on players. The effectiveness of the team depends not only on the high level of gaming interaction. but also on the relationship between the players. The work is based on the material of sports teams and is devoted to the study of the phenomenon of group cohesion. As a basic model. the authors choose a 4-factor model that describes cohesion in sports teams. The pape...

Flow Function of Pharmaceutical Powders Is Predominantly Governed by Cohesion, Not by Friction Coefficients.

Science.gov (United States)

Leung, Lap Yin; Mao, Chen; Srivastava, Ishan; Du, Ping; Yang, Chia-Yi

2017-07-01

The purpose of this study was to demonstrate that the flow function (FFc) of pharmaceutical powders, as measured by rotational shear cell, is predominantly governed by cohesion but not friction coefficients. Driven by an earlier report showing an inverse correlation between FFc and the cohesion divided by the corresponding pre-consolidation stress (Wang et al. 2016. Powder Tech. 294:105-112), we performed analysis on a large data set containing 1130 measurements from a ring shear tester and identified a near-perfect inverse correlation between the FFc and cohesion. Conversely, no correlation was found between FFc and friction angles. We also conducted theoretical analysis and estimated such correlations based on Mohr-Coulomb failure model. We discovered that the correlation between FFc and cohesion can sustain as long as the angle of internal friction at incipient flow is not significantly larger than the angle of internal friction at steady-state flow, a condition covering almost all pharmaceutical powders. The outcome of this study bears significance in pharmaceutical development. Because the cohesion value is strongly influenced by the interparticle cohesive forces, this study effectively shows that it is more efficient to improve the pharmaceutical powder flow by lowering the interparticle cohesive forces than by lowering the interparticle frictions. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Winnowing and Flocculation in Bio-physical Cohesive Substrate: A Flume Experimental and Estuarine Study

Science.gov (United States)

Ye, L.; Parsons, D. R.; Manning, A. J.

2016-12-01

Cohesive sediment, or mud, is ubiquitously found in most aqueous environments, such as coasts and estuaries. The study of cohesive sediment behaviors requires the synchronous description of mutual interactions of grains (e.g., winnowing and flocculation), their physical properties (e.g., grain size) and also the ambient water. Herein, a series of flume experiments (14 runs) with different substrate mixtures of sand-clay-EPS (Extracellular Polymeric Substrates: secreted by aquatic microorganisms) are combined with an estuarine field survey (Dee estuary, NW England) to investigate the behavior of suspensions over bio-physical cohesive substrates. The experimental results indicate that winnowing and flocculation occur pervasively in bio-physical cohesive flow systems. Importantly however, the evolution of the bed and bedform dynamics and hence turbulence production can be lower when cohesivity is high. The estuarine survey also revealed that the bio-physical cohesion provided by both the clay and microorganism fractions in the bed, that pervasively exists in many natural estuarine systems, plays a significant role in controlling the interactions between bed substrate and sediment suspension and deposition, including controlling processes such as sediment winnowing, flocculation and re-deposition. Full understanding of these processes are essential in advancing sediment transport modelling and prediction studies across natural estuarine systems and the work will report on an improved conceptual model for sediment sorting deposition in bio-physical cohesive substrates.

Happiness matters : exploring the linkages between personality, personal happiness, and work-related psychological health among priests and sisters in Italy

OpenAIRE

Francis, Leslie J.; Crea, Giuseppe

2017-01-01

This study responds to the challenge posed by Rossetti’s work to explore the antecedents and consequences of individual differences in happiness among priests and religious sisters. The Oxford Happiness Questionnaire was completed together with measures of personality and work-related psychological health by 95 priests and 61 religious sisters. Overall the data demonstrated high levels of personal happiness among priests and religious sisters, but also significant signs of vulnerability. Pers...

Do brothers and sisters of siblings with intelectual disability need the support of social work?

OpenAIRE

Cardová, Michaela

2007-01-01

This thesis explores the experience and support needs of siblings with a brother or sister with intellectual disability. Through review of what is a quite limited literature and from original qualitative research, involving interviews with siblings, the author examines their social reality, focusing especially on their relationships with their disabled brother or sister and with the wider society. Particular attention is given to identifying to what extent the siblings' lives are influenced b...

Auto consolidated cohesive sediments erosion; Erosion des sediments cohesifs en autoconsolidation

Energy Technology Data Exchange (ETDEWEB)

Ternat, F

2007-02-15

Pollutants and suspended matters of a river can accumulate into the sedimentary column. Once deposited, they are submitted to self-weight consolidation processes, ageing and burying, leading to an increase of their erosion resistance. Pollutant fluxes can be related to sedimentary fluxes, determined by threshold laws. In this work, an erosion threshold model is suggested by introducing a cohesion force into the usual force balance. A model of cohesion is developed on the basis of interactions between argillaceous cohesive particles (clays), particularly the Van der Waals force, whose parameterization is ensured by means of granulometry and porosity. Artificial erosion experiments were performed in a recirculating erosion flume with natural cored sediments where critical shear stress measurements were performed. Other analyses provided granulometry and porosity. The results obtained constitute a good database for the literature. The model is then applied to the experimental conditions and gives good agreement with measurements. An example of the accounting for self-weight consolidation processes is finally suggested, before finishing on a Mohr like diagram dedicated to soft cohesive sediment erosion. (author)

Transformational leadership and task cohesion in sport: the mediating role of inside sacrifice.

Science.gov (United States)

Cronin, Lorcan Donal; Arthur, Calum Alexander; Hardy, James; Callow, Nichola

2015-02-01

In this cross-sectional study, we examined a mediational model whereby transformational leadership is related to task cohesion via sacrifice. Participants were 381 American (Mage = 19.87 years, SD = 1.41) Division I university athletes (188 males, 193 females) who competed in a variety of sports. Participants completed measures of coach transformational leadership, personal and teammate inside sacrifice, and task cohesion. After conducting multilevel mediation analysis, we found that both personal and teammate inside sacrifice significantly mediated the relationships between transformational leadership behaviors and task cohesion. However, there were differential patterns of these relationships for male and female athletes. Interpretation of the results highlights that coaches should endeavor to display transformational leadership behaviors as they are related to personal and teammate inside sacrifices and task cohesion.

Bedform development in mixed sand-mud: The contrasting role of cohesive forces in flow and bed

Science.gov (United States)

Baas, Jaco H.; Davies, Alan G.; Malarkey, Jonathan

2013-01-01

The majority of subaqueous sediment on Earth consists of mixtures of cohesive clay and cohesionless sand and silt, but the role of cohesion on the development and stability of sedimentary bedforms is poorly understood. The results of new laboratory flume experiments on bedform development in cohesive, mixed sand-mud beds are compared with the results of previous experiments in which cohesive forces in high concentration clay flows dominated bedform development. Even though both series of mixed sand-mud experiments were conducted at similar flow velocities, the textural and structural properties of the bedforms were sufficiently different to permit the designation of key criteria for identifying bedform generation under cohesive flows against bedform generation on cohesive substrates. These criteria are essential for improving bedform size predictions in sediment transport modelling in modern sedimentary environments and for the reconstruction of depositional processes in the geological record. The current ripples developing on the cohesive, mixed sand-mud beds, with bed mud fractions of up to 18%, were significantly smaller than equivalent bedforms in noncohesive sand. Moreover, the bedform height showed a stronger inversely proportional relationship with initial bed mud fraction than the bedform wavelength. This is in contrast with the bedforms developing under the cohesive clay flows, which tend to increase in size with increasing suspended clay concentration until the flow turbulence is fully suppressed. Selective removal of clay from the mixed beds, i.e., clay winnowing, was found to be an important process, with 82-100% clay entrained into suspension after 2 h of bedform development. This winnowing process led to the development of a sand-rich armouring layer. This armouring layer is inferred to have protected the underlying mixed sand-mud from prolonged erosion, and in conjunction with strong cohesive forces in the bed may have caused the smaller size of the

Cohesion and coordination effects on transition metal surface energies

Science.gov (United States)

Ruvireta, Judit; Vega, Lorena; Viñes, Francesc

2017-10-01

Here we explore the accuracy of Stefan equation and broken-bond model semiempirical approaches to obtain surface energies on transition metals. Cohesive factors are accounted for either via the vaporization enthalpies, as proposed in Stefan equation, or via cohesive energies, as employed in the broken-bond model. Coordination effects are considered including the saturation degree, as suggested in Stefan equation, employing Coordination Numbers (CN), or as the ratio of broken bonds, according to the bond-cutting model, considering as well the square root dependency of the bond strength on CN. Further, generalized coordination numbers CN bar are contemplated as well, exploring a total number of 12 semiempirical formulations on the three most densely packed surfaces of 3d, 4d, and 5d Transition Metals (TMs) displaying face-centered cubic (fcc), body-centered cubic (bcc), or hexagonal close-packed (hcp) crystallographic structures. Estimates are compared to available experimental surface energies obtained extrapolated to zero temperature. Results reveal that Stefan formula cohesive and coordination dependencies are only qualitative suited, but unadvised for quantitative discussion, as surface energies are highly overestimated, favoring in addition the stability of under-coordinated surfaces. Broken-bond cohesion and coordination dependencies are a suited basis for quantitative comparison, where square-root dependencies on CN to account for bond weakening are sensibly worse. An analysis using Wulff shaped averaged surface energies suggests the employment of broken-bond model using CN to gain surface energies for TMs, likely applicable to other metals.

Relationship between Family Adaptability, Cohesion and Adolescent Problem Behaviors: Curvilinearity of Circumplex Model

Science.gov (United States)

Joh, Ju Youn; Kim, Sun; Park, Jun Li

2013-01-01

Background The Family Adaptability and Cohesion Evaluation Scale (FACES) III using the circumplex model has been widely used in investigating family function. However, the criticism of the curvilinear hypothesis of the circumplex model has always been from an empirical point of view. This study examined the relationship between adolescent adaptability, cohesion, and adolescent problem behaviors, and especially testing the consistency of the curvilinear hypotheses with FACES III. Methods We used the data from 398 adolescent participants who were in middle school. A self-reported questionnaire was used to evaluate the FACES III and Youth Self Report. Results According to the level of family adaptability, significant differences were evident in internalizing problems (P = 0.014). But, in externalizing problems, the results were not significant (P = 0.305). Also, according to the level of family cohesion, significant differences were in internalizing problems (P = 0.002) and externalizing problems (P = 0.004). Conclusion The relationship between the dimensions of adaptability, cohesion and adolescent problem behaviors was not curvilinear. In other words, adolescents with high adaptability and high cohesion showed low problem behaviors. PMID:23730484

Relationship between Family Adaptability, Cohesion and Adolescent Problem Behaviors: Curvilinearity of Circumplex Model.

Science.gov (United States)

Joh, Ju Youn; Kim, Sun; Park, Jun Li; Kim, Yeon Pyo

2013-05-01

The Family Adaptability and Cohesion Evaluation Scale (FACES) III using the circumplex model has been widely used in investigating family function. However, the criticism of the curvilinear hypothesis of the circumplex model has always been from an empirical point of view. This study examined the relationship between adolescent adaptability, cohesion, and adolescent problem behaviors, and especially testing the consistency of the curvilinear hypotheses with FACES III. We used the data from 398 adolescent participants who were in middle school. A self-reported questionnaire was used to evaluate the FACES III and Youth Self Report. According to the level of family adaptability, significant differences were evident in internalizing problems (P = 0.014). But, in externalizing problems, the results were not significant (P = 0.305). Also, according to the level of family cohesion, significant differences were in internalizing problems (P = 0.002) and externalizing problems (P = 0.004). The relationship between the dimensions of adaptability, cohesion and adolescent problem behaviors was not curvilinear. In other words, adolescents with high adaptability and high cohesion showed low problem behaviors.

Corporal Punishment and Child Aggression: Ethnic-Level Family Cohesion as a Moderator.

Science.gov (United States)

Lee, Yoona; Watson, Malcolm W

2017-04-01

Ethnicity has been examined as a putative moderator between parents' use of corporal punishment and children's externalizing behaviors. Yet, the reasons for this potential ethnic-level moderator have not been fully examined. The primary objective of this study was to examine whether the effect of corporal punishment on aggression is ethnic-specific using major racial groups inside and outside the U.S. samples and how the mean levels of cohesion in family relationships as found in different ethnic groups moderate the association between mothers' use of corporal punishment and children's aggression. A total of 729 mothers who had children aged 7 to 13 years were sampled from five ethnic groups (i.e., European American, African American, Hispanic American, Korean, and Chinese). Several hypotheses were tested to examine the moderating effect of ethnic-level, family cohesion on the relation of corporal punishment to children's aggression. As expected, the mean level of family cohesion was significantly different across ethnicities. Consistent results across parallel multilevel and fixed effect models showed that high corporal punishment was associated with more aggression in all ethnicities, but there was a significant variation in the association across ethnicities, and the variation was explained by ethnic-level family cohesion. There were weaker associations between corporal punishment and child aggression among ethnic groups with high family cohesion and stronger associations among ethnic groups with low family cohesion. Ethnic/cultural variation in this study emphasizes the importance of understanding family environment of diverse ethnic groups when evaluating the influence of corporal punishment on child behavior in different ethnic/cultural contexts.

Social Capital or Social Cohesion: What Matters for Subjective Well-Being?

Science.gov (United States)

Klein, Carlo

2013-01-01

The theoretical analysis of the concepts of social capital and of social cohesion shows that social capital should be considered as a micro concept whereas social cohesion, being a broader concept than social capital, is a more appropriate concept for macro analysis. Therefore, we suggest that data on the individual level should only be used to…

Symptom fluctuations, self-esteem, and cohesion during group cognitive behaviour therapy for early psychosis.

Science.gov (United States)

Lecomte, Tania; Leclerc, Claude; Wykes, Til

2018-03-01

Group cohesion has been linked to positive changes in self-esteem and in symptoms during group psychotherapy in people with psychosis. These changes may be linked to changes in symptoms as fluctuations in self-esteem have been linked to symptom fluctuations. We aimed to determine the relationship between these three factors - group cohesion, self-esteem, and symptoms - during group cognitive behaviour therapy for psychosis (GCBTp). We hypothesized that group cohesion would precede changes in symptoms and self-esteem and that improvements in self-esteem would precede improvements in symptoms. This is an uncontrolled longitudinal study recruiting from a convenience sample within two early psychosis clinics. Sixty-six individuals from first episode of psychosis treatment programmes participated in this study and received 24 sessions of a validated GCBTp protocol. Participants answered a brief questionnaire at the end of each session, measuring their group cohesion, self-esteem, and perception of their symptoms as worse, same, or better than usual. Orthogonal polynomial contrasts for time effects were estimated with a mixed model for repeated measures with a random cluster effect and revealed a quartic trend regarding changes in symptoms over the 24 sessions. Self-esteem, symptoms, and group cohesion were strongly linked during a given session. Also, self-esteem changes predicted changes in symptoms up to two sessions later, and symptoms changes predicted self-esteem changes at the next session. Group cohesion preceded improvements in both self-esteem and symptoms; self-esteem also predicted improvements in group cohesion. These results suggest that self-esteem and symptoms influence each other during therapy, with improvements in one leading to improvements in the other. Group cohesion also appears to be an essential prerequisite to positive changes in self-esteem and symptoms during GCBTp. This study emphasizes the interrelation between self-esteem improvements and

Sex differences in the development of perceived family cohesion and depressive symptoms in Taiwanese adolescents.

Science.gov (United States)

Sze, Tat-Ming; Hsieh, Pei-Jung; Lin, Sieh-Hwa; Chen, I-Jung

2013-08-01

This study investigates the progression of family cohesion perceptions and depressive symptoms during the character development stage in adolescents. Data were used from the Taiwan Youth Project. The final sample comprised 2,690 adolescents with 1,312 girls (48.8%; M age = 13.0 yr., SD = 0.5). Latent curve growth analysis was employed to explore these developments. Seventh-grade girls reported greater family cohesion and more depressive symptoms than boys, and boys reported greater growth in family cohesion than girls. However, progression of depressive symptoms was not associated with the child's sex. Higher perceived family cohesion in Grade 7 correlated with less increase of depressive symptoms from Grades 9 to 11. The long-term positive influence of family cohesion on depressive symptoms is discussed.

Identification of Putative Mek1 Substrates during Meiosis in Saccharomyces cerevisiae Using Quantitative Phosphoproteomics.

Directory of Open Access Journals (Sweden)

Raymond T Suhandynata

Full Text Available Meiotic recombination plays a key role in sexual reproduction as it generates crossovers that, in combination with sister chromatid cohesion, physically connect homologous chromosomes, thereby promoting their proper segregation at the first meiotic division. Meiotic recombination is initiated by programmed double strand breaks (DSBs catalyzed by the evolutionarily conserved, topoisomerase-like protein Spo11. Repair of these DSBs is highly regulated to create crossovers between homologs that are distributed throughout the genome. This repair requires the presence of the mitotic recombinase, Rad51, as well as the strand exchange activity of the meiosis-specific recombinase, Dmc1. A key regulator of meiotic DSB repair in Saccharomyces cerevisiae is the meiosis-specific kinase Mek1, which promotes interhomolog strand invasion and is required for the meiotic recombination checkpoint and the crossover/noncrossover decision. Understanding how Mek1 regulates meiotic recombination requires the identification of its substrates. Towards that end, an unbiased phosphoproteomic approach utilizing Stable Isotope Labeling by Amino Acids in Cells (SILAC was utilized to generate a list of potential Mek1 substrates, as well as proteins containing consensus phosphorylation sites for cyclin-dependent kinase, the checkpoint kinases, Mec1/Tel1, and the polo-like kinase, Cdc5. These experiments represent the first global phosphoproteomic dataset for proteins in meiotic budding yeast.

The iron-sulfur cluster assembly network component NARFL is a key element in the cellular defense against oxidative stress.

Science.gov (United States)

Corbin, Monique V; Rockx, Davy A P; Oostra, Anneke B; Joenje, Hans; Dorsman, Josephine C

2015-12-01

Aim of this study was to explore cellular changes associated with increased resistance to atmospheric oxygen using high-resolution DNA and RNA profiling combined with functional studies. Two independently selected oxygen-resistant substrains of HeLa cells (capable of proliferating at >80% O2, i.e. hyperoxia) were compared with their parental cells (adapted to growth at 20% O2, but unable to grow at >80% O2). A striking consistent alteration found to be associated with the oxygen-resistant state appeared to be an amplified and overexpressed region on chromosome 16p13.3 harboring 21 genes. The driver gene of this amplification was identified by functional studies as NARFL, which encodes a component of the cytosolic iron-sulfur cluster assembly system. In line with this result we found the cytosolic c-aconitase activity as well as the nuclear protein RTEL1, both Fe-S dependent proteins, to be protected by NARFL overexpression under hyperoxia. In addition, we observed a protective effect of NARFL against hyperoxia-induced loss of sister-chromatid cohesion. NARFL thus appeared to be a key factor in the cellular defense against hyperoxia-induced oxidative stress in human cells. Our findings suggest that new insight into age-related degenerative processes may come from studies that specifically address the involvement of iron-sulfur proteins. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Cohesiveness in financial news and its relation to market volatility.

Science.gov (United States)

Piškorec, Matija; Antulov-Fantulin, Nino; Novak, Petra Kralj; Mozetič, Igor; Grčar, Miha; Vodenska, Irena; Smuc, Tomislav

2014-05-22

Motivated by recent financial crises, significant research efforts have been put into studying contagion effects and herding behaviour in financial markets. Much less has been said regarding the influence of financial news on financial markets. We propose a novel measure of collective behaviour based on financial news on the Web, the News Cohesiveness Index (NCI), and we demonstrate that the index can be used as a financial market volatility indicator. We evaluate the NCI using financial documents from large Web news sources on a daily basis from October 2011 to July 2013 and analyse the interplay between financial markets and finance-related news. We hypothesise that strong cohesion in financial news reflects movements in the financial markets. Our results indicate that cohesiveness in financial news is highly correlated with and driven by volatility in financial markets.

Cohesiveness in Financial News and its Relation to Market Volatility

Science.gov (United States)

Piškorec, Matija; Antulov-Fantulin, Nino; Novak, Petra Kralj; Mozetič, Igor; Grčar, Miha; Vodenska, Irena; Šmuc, Tomislav

2014-01-01

Motivated by recent financial crises, significant research efforts have been put into studying contagion effects and herding behaviour in financial markets. Much less has been said regarding the influence of financial news on financial markets. We propose a novel measure of collective behaviour based on financial news on the Web, the News Cohesiveness Index (NCI), and we demonstrate that the index can be used as a financial market volatility indicator. We evaluate the NCI using financial documents from large Web news sources on a daily basis from October 2011 to July 2013 and analyse the interplay between financial markets and finance-related news. We hypothesise that strong cohesion in financial news reflects movements in the financial markets. Our results indicate that cohesiveness in financial news is highly correlated with and driven by volatility in financial markets. PMID:24849598

The role of bio-physical cohesive substrates on sediment winnowing and bedform development

Science.gov (United States)

Ye, Leiping; Parsons, Daniel; Manning, Andrew

2017-04-01

Existing sediment transport and bedform size predictions for natural open-channel flows in many environments are seriously impeded by a lack of process-based knowledge concerning the dynamics of complex bed sediment mixtures comprising cohesionless sand and biologically-active cohesive muds. A series of flume experiments (14 experimental runs) with different substrate mixtures of sand-clay-EPS (Extracellular Polymeric Substance) are combined with a detailed estuarine field survey (Dee estuary, NW England) to investigate the development of bedform morphologies and characteristics of suspended sediment over bio-physical cohesive substrates. The experimental results indicate that winnowing and sediment sorting can occur pervasively in bio-physical cohesive sediment - flow systems. Importantly however, the evolution of the bed and bedform dynamics, and hence turbulence production, is significantly reduced as bed substrate cohesivity increases. The estuarine subtidal zone survey also revealed that the bio-physical cohesion provided by both the clay and microorganism fractions in the bed plays a significant role in controlling the interactions between bed substrate and sediment suspension, deposition and bedform generation. The work will be presented here concludes by outlining the need to extend and revisit the effects of cohesivity in morphodynamic systems and the sets of parameters presently used in numerical modelling, particularly in the context of the impact of climate change on estuarine and coastal systems.

Design of Normal Concrete Mixtures Using Workability-Dispersion-Cohesion Method

OpenAIRE

Qasrawi, Hisham

2016-01-01

The workability-dispersion-cohesion method is a new proposed method for the design of normal concrete mixes. The method uses special coefficients called workability-dispersion and workability-cohesion factors. These coefficients relate workability to mobility and stability of the concrete mix. The coefficients are obtained from special charts depending on mix requirements and aggregate properties. The method is practical because it covers various types of aggregates that may not be within sta...

The Corporate Stake in Social Cohesion

Science.gov (United States)

Oketch, Moses O.

2005-01-01

Corporate Social Responsibility (CSR) is a function that transcends, but includes, making profits, creating jobs, and producing goods and services. The effectiveness with which corporations perform this function determines their contribution (or lack of contribution) to social cohesion. This article therefore presents a discussion of some of the…

Numerical insight into the micromechanics of jet erosion of a cohesive granular material

Directory of Open Access Journals (Sweden)

Cuéllar Pablo

2017-01-01

Full Text Available Here we investigate the physical mechanisms behind the surface erosion of a cohesive granular soil induced by an impinging jet by means of numerical simulations coupling fluid and grains at the microscale. The 2D numerical model combines the Discrete Element and Lattice Boltzmann methods (DEM-LBM and accounts for the granular cohesion with a contact model featuring a paraboloidal yield surface. Here we review first the hydrodynamical conditions imposed by the fluid jet on a solid granular packing, turning then the attention to the impact of cohesion on the erosion kinetics. Finally, the use of an additional subcritical debonding damage model based on the work of Silvani and co-workers provides a novel insight into the internal solicitation of the cohesive granular sample by the impinging jet.

Numerical insight into the micromechanics of jet erosion of a cohesive granular material

Science.gov (United States)

Cuéllar, Pablo; Benseghier, Zeyd; Luu, Li-Hua; Bonelli, Stéphane; Delenne, Jean-Yves; Radjaï, Farhang; Philippe, Pierre

2017-06-01

Here we investigate the physical mechanisms behind the surface erosion of a cohesive granular soil induced by an impinging jet by means of numerical simulations coupling fluid and grains at the microscale. The 2D numerical model combines the Discrete Element and Lattice Boltzmann methods (DEM-LBM) and accounts for the granular cohesion with a contact model featuring a paraboloidal yield surface. Here we review first the hydrodynamical conditions imposed by the fluid jet on a solid granular packing, turning then the attention to the impact of cohesion on the erosion kinetics. Finally, the use of an additional subcritical debonding damage model based on the work of Silvani and co-workers provides a novel insight into the internal solicitation of the cohesive granular sample by the impinging jet.

Family Cohesion in the Lives of Mexican American and European American Parents

Science.gov (United States)

Behnke, Andrew O.; MacDermid, Shelley M.; Coltrane, Scott L.; Parke, Ross D.; Duffy, Sharon; Widaman, Keith F.

2008-01-01

This study investigated similarities and differences in relations between stress and parenting behaviors for 509 Mexican American and European American fathers and mothers in Southern California. Our model posited that family cohesion mediates the relation between stressors and parenting behavior, and we found that family cohesion strongly…

PICH promotes sister chromatid disjunction and co-operates with topoisomerase II in mitosis

DEFF Research Database (Denmark)

Nielsen, Christian Thomas Friberg; Huttner, Diana; Bizard, Anna H

2015-01-01

PICH is a SNF2 family DNA translocase that binds to ultra-fine DNA bridges (UFBs) in mitosis. Numerous roles for PICH have been proposed from protein depletion experiments, but a consensus has failed to emerge. Here, we report that deletion of PICH in avian cells causes chromosome structural......-193-treated cells. We propose that PICH and Topo II cooperate to prevent chromosome missegregation events in mitosis....

Mouse RAD54 affects DNA double-strand break repair and sister chromatid exchange

NARCIS (Netherlands)

H.B. Beverloo (Berna); R.D. Johnson (Roger); M. Jasin (Maria); R. Kanaar (Roland); J.H.J. Hoeijmakers (Jan); M.L.G. Dronkert (Mies)

2000-01-01

textabstractCells can achieve error-free repair of DNA double-strand breaks (DSBs) by homologous recombination through gene conversion with or without crossover. In contrast, an alternative homology-dependent DSB repair pathway, single-strand annealing (SSA), results in deletions. In this study, we

Sister chromatid exchanges (SCEs) in lymphocytes of inhabitants in high background radiation area

International Nuclear Information System (INIS)

Li Jinsheng; Zheng Qiaoling

1985-01-01

Blood samples were taken from 126 students of 15-16 years old, living in the high background radiation area, and from 124 controls of the same age range, living in the normal background radiation area. All students were interviewed for evaluation of their health status. Whole blood cultures were done with RPMI 1640 medium supplemented with 20% fetal calf serum and antibiotics, The culture were incubated for 54-56 h in the presence of BrdU (10 μg/ml). Metaphases were stained for SCE using a modified techniqu of perry and Wolff. From each person 20 second division metaphases were analysed for SCEs. The average frequencies of SCEs observed in the high background group and the control group are presented. More SCEs were observed in the high background group than in the control with a statistically signigicant difference. In regard to the sex factor, it was found that the SCE frequencies in both sexes of the high background group were slightly higher than those in the control group. These findings suggest that continuous low-level irradiation by the high background radiation may induce increased frequency of SCEs

The kinetochore of the Lepidoptera, (2)

International Nuclear Information System (INIS)

Maeki, Kodo

1980-01-01

The chromosomes of Graphium Sarpedon (n, 20) and Eumeta variegata were examined by the acetoorcein squash method. In the equatorial plate of M-2 metaphase, two sister chromatids (rod-type) appeared in linear arrangement. The spindle fibers then gathered to the chromosomal part toward the cell pole, which condensed longwise on the other side. In the second anaphase, the two sister chromatids moved to the opposite poles, they appeared to move toward the pole ends-first. The M-2 metaphase and anaphase were identified only for the chromosomes equipped with the diffuse kinetochore structure. The male larvae of Graphium Sarpedon at the last-instar were irradiated with 800, 1000, 1500 or 2000 R of 60 Co to induce chromosome fragmentation, and killed 18, 21, 24, 27 and 30 hrs after the irradiation. The chromosomal aberration at the meitotic stage after the irradiation of 1500 R and 2000 R was pronounced. Although the normal haploid chromosome number of G. sarpedon is 20, it was found that the irradiated larvae had 21 or 19 chromosomes at the M-1 metaphase. The aberration resulted from chromosomal fusion as well as from fragmentation during meiosis. It was suggested that the induced fragment chromosomes each carry kinetochore. In general, it is considered that the chromosomes of lepidopteran insects were characterized by holokinetic organization. (Kaihara, S.)

Evaluation of cytogenetic and DNA damage in human lymphocytes treated with adrenaline in vitro.

Science.gov (United States)

Djelić, Ninoslav; Radaković, Milena; Spremo-Potparević, Biljana; Zivković, Lada; Bajić, Vladan; Stevanović, Jevrosima; Stanimirović, Zoran

2015-02-01

Catechol groups can be involved in redox cycling accompanied by generation of reactive oxygen species (ROS) which may lead to oxidative damage of cellular macromolecules including DNA. The objective of this investigation was to evaluate possible genotoxic effects of a natural catecholamine adrenaline in cultured human lymphocytes using cytogenetic (sister chromatid exchange and micronuclei) and the single cell gel electrophoresis (Comet) assay. In cytogenetic tests, six experimental concentrations of adrenaline were used in a range from 0.01-500 μM. There were no indications of genotoxic effects of adrenaline in sister chromatid exchange and micronucleus tests. However, at four highest concentrations of adrenaline (5 μM, 50 μM, 150 μM and 300 μM) we observed a decreased mitotic index and cell-cycle delay. In addition, in the Comet assay we used adrenaline in a range from 0.0005-500 μM, at two treatment times: 15 min or 60 min. In contrast to cytogenetic analysis, there was a dose-dependent increase of DNA damage detected in the Comet assay. These effects were significantly reduced by concomitant treatment with quercetin or catalase. Therefore, the obtained results indicate that adrenaline may exhibit genotoxic effects in cultured human lymphocytes, most likely due to production of reactive oxygen species. Copyright © 2014 Elsevier Ltd. All rights reserved.

20 CFR 410.340 - Determination of relationship; parent, brother, or sister.

Science.gov (United States)

2010-04-01

... domiciled (see § 410.392) at the time of his death would find, under the law they would apply in determining..., brother, or sister. Where, under such law, the individual does not bear the relationship to the miner of...

Bedform development and morphodynamics in mixed cohesive sediment substrates: the importance of winnowing and flocculation

Science.gov (United States)

Ye, Leiping; Parsons, Daniel; Manning, Andrew

2016-04-01

There remains a lack of process-based knowledge of sediment dynamics within flows over bedforms generated in complex mixtures of cohesionless sand and biologically-active cohesive muds in natural estuarine flow systems. The work to be presented forms a part of the UK NERC "COHesive BEDforms (COHBED)" project which aims to fill this gap in knowledge. Herein results from a field survey in sub-tidal zone of Dee estuary (NW, England) and a set of large-scale laboratory experiments, conducted using mixtures of non-cohesive sands, cohesive muds and Xanthan gum (as a proxy for the biological stickiness of Extracellular Polymeric Substances (EPS)) will be presented. The results indicate the significance of biological-active cohesive sediments in controlling winnowing rates and flocculation dynamics, which contributes significantly to rates of bedform evolution.

An Investigation into the Use of Cohesive Devises in Iranian High School EFL Textbooks

Directory of Open Access Journals (Sweden)

Mansour Shabani

2015-07-01

Full Text Available The present study aimed at probing into the use of grammatical and lexical cohesive subdevices in Iranian high school EFL textbooks. To this end, the reading sections of three high school EFL textbooks and one pre-university EFL textbook were analyzed in terms of the distribution of grammatical and lexical cohesive subdevices. The results of One-way ANOVA illustrated that: athere are no significant differences among the frequencies of grammatical cohesive subdevices across grade 1 high school EFL textbook and the pre-university EFL textbook, bthere are significant differences among the frequencies of grammatical cohesive subdevices across grades 2 and 3 high school EFL textbooks. Moreover, the results of Chi-Square test showed that the significant values of all of the lexical cohesive subdevices were higher than .05 across each of the Iranian EFL high school textbooks. These findings can be beneficial for textbook writers, materials developers and EFL teachers.

A Molecular-Scale Understanding of Cohesion and Fracture in P3HT:Fullerene Blends

KAUST Repository

Tummala, Naga Rajesh

2015-04-21

Quantifying cohesion and understanding fracture phenomena in thin-film electronic devices are necessary for improved materials design and processing criteria. For organic photovoltaics (OPVs), the cohesion of the photoactive layer portends its mechanical flexibility, reliability, and lifetime. Here, the molecular mechanism for the initiation of cohesive failure in bulk heterojunction (BHJ) OPV active layers derived from the semiconducting polymer poly-(3-hexylthiophene) [P3HT] and two mono-substituted fullerenes is examined experimentally and through molecular-dynamics simulations. The results detail how, under identical conditions, cohesion significantly changes due to minor variations in the fullerene adduct functionality, an important materials consideration that needs to be taken into account across fields where soluble fullerene derivatives are used.

Multiculturalism and Community Cohesion in Britain: The Case of Arab Minority

Directory of Open Access Journals (Sweden)

Mohamed Benitto

2015-11-01

Full Text Available This article falls within the scope of debate about 'Community Cohesion' in Britain. Community cohesion is at the centre of public policy initiated in response to the urban disturbances in northern towns. Many official reports pointed out that lack of community cohesion is an element jeopardizing security and safe coexistence. In this sense, this article explores hindrances to intergroup coexistence, given that this issue is the main concern in this pluralist society since the attacks in London in July, 7, 2005, through the study of intercultural relations between Arab minority of London and mainstream society in Britain. This research adopts an approach which aims to contribute to the understanding of the reasons hampering community cohesion through juxtaposition of viewpoints of both the minority and majority group. The originality of this approach lies in the fact that it tackles the issue of integration from two sided points of view: the point of the majority group and the point of view of the minority group; unlike most literature on intergroup relations which basically focus on the integration of the minority and its daptation to the dominant culture.

The centenary of Janssens's chiasmatype theory.

Science.gov (United States)

Koszul, Romain; Meselson, Matthew; Van Doninck, Karine; Vandenhaute, Jean; Zickler, Denise

2012-06-01

The segregation and random assortment of characters observed by Mendel have their basis in the behavior of chromosomes in meiosis. But showing this actually to be the case requires a correct understanding of the meiotic behavior of chromosomes. This was achieved only gradually, over several decades, with much dispute and confusion along the way. One crucial step in the understanding of meiosis was provided in 1909 by Frans Alfons Janssens who published in La Cellule an article entitled "La théorie de la Chiasmatypie. Nouvelle interprétation des cinèses de maturation," which contains the first description of the chiasma structure. He observed that, of the four chromatids present at the connection sites (chiasmata sites) at diplotene or anaphase of the first meiotic division, two crossed each other and two did not. He therefore postulated that the maternal and paternal chromatids that crossed penetrated the other until they broke and rejoined in maternal and paternal segments new ways; the other two chromatids remained free and thus intact. This allowed him also to propose that the chromatids distributed in the four nuclei issued from the second meiotic division had various combinations of maternal and paternal segments of each chromosome. And conversely, permitted the appreciation that the laws of Mendelian segregation required breakage and joining (crossing over) between homologous non-sister chromatids. Although Janssens's article found a broad appreciative audience and had a large influence on the chromosomal theory at that time, his theory was resisted by both geneticists and cytologists for several decades. This Perspectives aims to highlight the novelty of Janssens's chiasmatype theory by examining the historical background and our actual understanding of meiotic recombination.

Social cohesion and integration: Learning active citizenship

NARCIS (Netherlands)

Jansen, T.J.M.; Chioncel, N.E.; Dekkers, H.P.J.M.

2006-01-01

This article starts from a conceptual clarification of the notions social integration and social cohesion as a prerequisite for the reorientation of citizenship education. Turning away from uncritically reproduced assumptions represented in mainstream `deficiency discourse', the article first

Alcohol Use Severity Among Adult Hispanic Immigrants: Examining the Roles of Family Cohesion, Social Support, and Gender.

Science.gov (United States)

Cano, Miguel Ángel; Sánchez, Mariana; Rojas, Patria; Ramírez-Ortiz, Daisy; Polo, Katherine L; Romano, Eduardo; De La Rosa, Mario

2018-03-21

This study examined (a) the direct association of family cohesion on alcohol use severity among adult Hispanic immigrants; (b) the indirect association of family cohesion on alcohol use severity via social support; and (c) if gender moderates the direct and indirect associations between family cohesion and alcohol use severity. Mediation and moderation analyses were conducted on a cross-sectional sample of 411 (men = 222, women = 189) participants from Miami-Dade, Florida. Findings indicate that higher family cohesion was directly associated with higher social support and lower alcohol use severity. Higher social support was also directly associated with lower alcohol use severity. Additionally, family cohesion had an indirect association with alcohol use severity via social support. Moderation analyses indicated that gender moderated the direct association between family cohesion and alcohol use severity, but did not moderate the indirect association. Some potential clinical implications may be that strengthening family cohesion may enhance levels of social support, and in turn, lower alcohol use severity among adult Hispanic immigrants. Furthermore, strengthening family cohesion may be especially beneficial to men in efforts to lower levels of alcohol use severity.

An acoustic method for predicting relative strengths of cohesive sediment deposits

Science.gov (United States)

Reed, A. H.; Sanders, W. M.

2017-12-01

Cohesive sediment dynamics are fundamentally determined by sediment mineralogy, organic matter composition, ionic strength of water, and currents. These factors work to bind the cohesive sediments and to determine depositional rates. Once deposited the sediments exhibit a nonlinear response to stress and they develop increases in shear strength. Shear strength is critically important in resuspension, transport, creep, and failure predictions. Typically, shear strength is determined by point measurements, both indirectly from free-fall penetrometers or directly on cores with a shear vane. These values are then used to interpolate over larger areas. However, the remote determination of these properties would provide continuos coverage, yet it has proven difficult with sonar systems. Recently, findings from an acoustic study on cohesive sediments in a laboratory setting suggests that cohesive sediments may be differentiated using parametric acoustics; this method pulses two primary frequencies into the sediment and the resultant difference frequency is used to determine the degree of acoustic nonlinearity within the sediment. In this study, two marine clay species, kaolinite and montmorillonite, and two biopolymers, guar gum and xanthan gum were mixed to make nine different samples. The samples were evaluated in a parametric acoustic measurement tank. From the parametric acoustic measurements, the quadratic nonlinearity coefficient (beta) was determined. beta was correlated with the cation exchange capacity (CEC), an indicator of shear strength. The results indicate that increased acoustic nonlinearity correlates with increased CEC. From this work, laboratory measurements indicate that this correlation may be used evaluate geotechnical properties of cohesive sediments and may provide a means to predict sediment weakness in subaqueous environments.

Topographic Signatures of Meandering Rivers with Differences in Outer Bank Cohesion

Science.gov (United States)

Kelly, S. A.; Belmont, P.

2014-12-01

Within a given valley setting, interactions between river hydraulics, sediment, topography, and vegetation determine attributes of channel morphology, including planform, width and depth, slope, and bed and bank properties. These feedbacks also govern river behavior, including migration and avulsion. Bank cohesion, from the addition of fine sediment and/or vegetation has been recognized in flume experiments as a necessary component to create and maintain a meandering channel planform. Greater bank cohesion slows bank erosion, limiting the rate at which a river can adjust laterally and preventing so-called "runaway widening" to a braided state. Feedbacks of bank cohesion on channel hydraulics and sediment transport may thus produce distinct topographic signatures, or patterns in channel width, depth, and point bar transverse slope. We expect that in bends of greater outer bank cohesion the channel will be narrower, deeper, and bars will have greater transverse slopes. Only recently have we recognized that biotic processes may imprint distinct topographic signatures on the landscape. This study explores topographic signatures of three US rivers: the lower Minnesota River, near Mankato, MN, the Le Sueur River, south central MN, and the Fall River, Rocky Mountain National Park, CO. Each of these rivers has variability in outer bank cohesion, quantified based on geotechnical and vegetation properties, and in-channel topography, which was derived from rtkGPS and acoustic bathymetry surveys. We present methods for incorporating biophysical feedbacks into geomorphic transport laws so that models can better simulate the spatial patterns and variability of topographic signatures.

Automated Behavior and Cohesion Assessment Tools, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — An important consideration of long duration space flight operations is interpersonal dynamics that effect crew cohesion and performance. Flight surgeons have stated...

An investigation of the genetic toxicology of irradiated foodstuffs using short-term test systems

International Nuclear Information System (INIS)

Phillips, B.J.; Kranz, E.; Elias, P.S.

1980-01-01

As part of a programme of short-term tests used to detect possible genetic toxicity in irradiated foodstuffs, cultured Chinese hamster ovary cells were exposed to extracts and digests of irradiated and unirradiated dates, fish and chicken and subjected to tests for cytotoxicity, sister chromatid exchange induction and mutation to thioguanine resistance. The results showed no evidence of genetic toxicity induced in food by irradiation. The general applicability of cell culture tests to the detection of mutagens in food is discussed. (author)

In vitro and in vivo genotoxicity of 1,3-butadiene and metabolites.

OpenAIRE

Arce, G T; Vincent, D R; Cunningham, M J; Choy, W N; Sarrif, A M

1990-01-01

1,3-Butadiene and two major genotoxic metabolites 3,4-epoxybutene (EB) and 1,2:3,4-diepoxybutane (DEB) were used as model compounds to determine if genetic toxicity findings in animal and human cells can aid in extrapolating animal toxicity data to man. Sister chromatid exchange (SCE) and micronucleus induction results indicated 1,3-butadiene was genotoxic in the bone marrow of the mouse but not the rat. This paralleled the chronic bioassays which showed mice to be more susceptible than rats ...

Leader Behaviors, Group Cohesion, and Participation in a Walking Group Program.

Science.gov (United States)

Izumi, Betty T; Schulz, Amy J; Mentz, Graciela; Israel, Barbara A; Sand, Sharon L; Reyes, Angela G; Hoston, Bernadine; Richardson, Dawn; Gamboa, Cindy; Rowe, Zachary; Diaz, Goya

2015-07-01

Less than half of all U.S. adults meet the 2008 Physical Activity Guidelines. Leader behaviors and group cohesion have been associated with increased participation or adherence in sports team and exercise class settings. Physical activity interventions in community settings that encompass these factors may enhance intervention adherence. The purpose of this study is to examine the impact of Community Health Promoter leader behaviors and group cohesion on participation in a walking group intervention among racially/ethnically diverse adults in low to moderate-income communities in Detroit, Michigan. Data for the current study were drawn from the Walk Your Heart to Health (WYHH) data set. WYHH was a multisite cluster RCT with a lagged intervention and outcome measurements at baseline and 4, 8, and 32 weeks. Pooled survey data from both intervention arms were used for the current study. Data were analyzed between August 2013 and October 2014. A total of 603 non-Hispanic black, non-Hispanic white, and Hispanic adults across five cohorts that began the 32-week WYHH intervention between March 2009 and October 2011. The intervention was a 32-week walking group program hosted by community- and faith-based organizations and facilitated by Community Health Promoters. Walking groups met three times per week for 90 minutes per session. To promote participation in or adherence to WYHH, Community Health Promoters used evidence-based strategies to facilitate group cohesion. Group members assumed increasing leadership responsibility for facilitating sessions over time. Participation in WYHH as measured by consistency of attendance. Community Health Promoter leader behaviors were positively associated with participation in WYHH. Social but not task cohesion was significantly associated with consistent participation. Social cohesion may mediate the relationship between leader behaviors and walking group participation. Providing leaders with training to build socially cohesive groups

Bartter syndrome in two sisters with a novel mutation of the CLCNKB gene, one with deafness.

Science.gov (United States)

Robitaille, Pierre; Merouani, Aicha; He, Ning; Pei, York

2011-09-01

This article describes two sisters with type III Bartter syndrome (BS) due to a novel missense variant of the CLCNKB gene. The phenotypic expression of the disease was very different in these two siblings. In one sister, the disease followed a very severe course, especially in the neonatal period and as a toddler. Both the classic symptoms and the biochemical features of the syndrome were striking. In addition, she presented with sensorineural deafness, a complication yet unreported in this subtype of BS In contrast, the least affected sister was symptom free and the biochemical features of the disease although present remained discrete throughout the prolonged follow-up. It is suggested that such a difference in the phenotypic expression of the disease is possibly secondary to the modifier effect of a gene and/or results from environmental factor(s).

Adult Sibling Relationships with Brothers and Sisters with Severe Disabilities

Science.gov (United States)

Rossetti, Zach; Hall, Sarah

2015-01-01

The purpose of this qualitative study was to examine perceptions of adult sibling relationships with a brother or sister with severe disabilities and the contexts affecting the relationships. Adult siblings without disabilities (N = 79) from 19 to 72 years of age completed an online survey with four open-ended questions about their relationship…

Family cohesion and posttraumatic intrusion and avoidance among war veterans: a 20-year longitudinal study.

Science.gov (United States)

Zerach, Gadi; Solomon, Zahava; Horesh, Danny; Ein-Dor, Tsachi

2013-02-01

The bi-directional relationships between combat-induced posttraumatic symptoms and family relations are yet to be understood. The present study assesses the longitudinal interrelationship of posttraumatic intrusion and avoidance and family cohesion among 208 Israeli combat veterans from the 1982 Lebanon War. Two groups of veterans were assessed with self-report questionnaires 1, 3 and 20 years after the war: a combat stress reaction (CSR) group and a matched non-CSR control group. Latent Trajectories Modeling showed that veterans of the CSR group reported higher intrusion and avoidance than non-CSR veterans at all three points of time. With time, there was a decline in these symptoms in both groups, but the decline was more salient among the CSR group. The latter also reported lower levels of family cohesion. Furthermore, an incline in family cohesion levels was found in both groups over the years. Most importantly, Autoregressive Cross-Lagged Modeling among CSR and non-CSR veterans revealed that CSR veterans' posttraumatic symptoms in 1983 predicted lower family cohesion in 1985, and lower family cohesion, in turn, predicted posttraumatic symptoms in 2002. The findings suggest that psychological breakdown on the battlefield is a marker for future family cohesion difficulties. Our results lend further support for the bi-directional mutual effects of posttraumatic symptoms and family cohesion over time.

Leadership, cohesion and groupthink

Directory of Open Access Journals (Sweden)

Iurchevici Iulia

2016-09-01

Full Text Available The Groupthink Phenomenon refers to the tendency of the members of a group to reach solidarity and cohesion, the trend that makes to bypass any questions which would lead to disputes. In such cases, if the members expect counter-arguments regarding a certain issue, they avoid to raise the matter. If it is believed that a question cannot be answered – it isn’t asked. Originally, Janis the author of the term, explains this process through the environment that has been established within groups that are in the leading position, but later, puts a strong emphasis towards the tendency to maintain the unanimity of the decision of the group. As preceding conditions of this decision-making process are listed the following: the high cohesion of the group, its isolation from other external sources of information, the lack of an impartial leadership, lack of appropriate legal framework and procedures in the decision - making process, and also “homogeneity of members, background and their ideology”. The Groupthink is manifested by: Illusion of Invulnerability, Collective Rationalization, Illusion of morality, Out – Group Stereotypes, Strong pressures towards conformism, Self – Censorship, Illusions of unanimity, and the presence of “Mind Guards”. In order to understand the decisions of a group, it is important that some analysis of Groupthink to be done, because in this way, can be controlled or eliminated the communicational distortion that occurs at a time among members forming these groups.

High prevalence of metabolic syndrome in young Hispanic women: findings from the national Sister to Sister campaign.

Science.gov (United States)

Rodriguez, Fátima; Naderi, Sahar; Wang, Yun; Johnson, Caitlin E; Foody, JoAnne M

2013-04-01

Hispanics are the fastest growing segment of the U.S. population and have a higher prevalence of cardiometabolic risk factors as compared with non-Hispanic whites. Further data suggests that Hispanics have undiagnosed complications of metabolic syndrome, namely diabetes mellitus, at an earlier age. We sought to better understand the epidemiology of metabolic syndrome in Hispanic women using data from a large, community-based health screening program. Using data from the Sister to Sister: The Women's Heart Health Foundation community health fairs from 2008 to 2009 held in 17 U.S. cities, we sought to characterize how cardiometabolic risk profiles vary across age for women by race and ethnicity. Metabolic syndrome was defined using the updated National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) guidelines, which included three or more of the following: Waist circumference ≥35 inches, triglycerides ≥150 mg/dL, high-density lipoprotein (HDL) <50 mg/dL, systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥85 mmHg, or a fasting glucose ≥100 mg/dL. A total of 6843 community women were included in the analyses. Metabolic syndrome had a prevalence of 35%. The risk-adjusted odds ratio for metabolic syndrome in Hispanic women versus white women was 1.7 (95% confidence interval, 1.4, 2.0). Dyslipidemia was the strongest predictor of metabolic syndrome among Hispanic women. This disparity appeared most pronounced for younger women. Additional predictors of metabolic syndrome included black race, increasing age, and smoking. In a large, nationally representative sample of women, we found that metabolic syndrome was highly prevalent among young Hispanic women. Efforts specifically targeted to identifying these high-risk women are necessary to prevent the cardiovascular morbidity and mortality associated with metabolic syndrome.

Noncontact Cohesive Swimming of Bacteria in Two-Dimensional Liquid Films.

Science.gov (United States)

Li, Ye; Zhai, He; Sanchez, Sandra; Kearns, Daniel B; Wu, Yilin

2017-07-07

Bacterial swimming in confined two-dimensional environments is ubiquitous in nature and in clinical settings. Characterizing individual interactions between swimming bacteria in 2D confinement will help to understand diverse microbial processes, such as bacterial swarming and biofilm formation. Here we report a novel motion pattern displayed by flagellated bacteria in 2D confinement: When two nearby cells align their moving directions, they tend to engage in cohesive swimming without direct cell body contact, as a result of hydrodynamic interaction but not flagellar intertwining. We further found that cells in cohesive swimming move with higher directional persistence, which can increase the effective diffusivity of cells by ∼3 times as predicted by computational modeling. As a conserved behavior for peritrichously flagellated bacteria, cohesive swimming in 2D confinement may be key to collective motion and self-organization in bacterial swarms; it may also promote bacterial dispersal in unsaturated soils and in interstitial space during infections.

Competition and social cohesion

Directory of Open Access Journals (Sweden)

Mario Libertini

2014-03-01

Full Text Available "Competition" and "social cohesion" are both protected by E.U. and Italian laws. The author moves from the analysis of the meaning of these two concepts, in order to reflect on their compatibility and the way to conciliate them. The central problem - in the opinion of the Author - is to abandon the myth of spontaneous markets' order and to rebuild a political order able to maintain and support, as far as possible, the competitive market economy, but also to govern economic processes in critical moments and situations.

Simulation of debonding in Al/epoxy T-peel joints using a potential-based cohesive zone model

KAUST Repository

Alfano, Marco

2011-06-10

In this work, a cohesive zone model of fracture is employed to study debonding in plastically deforming Al/epoxy T-peel joints. In order to model the adhesion between the bonded metal strips, the Park-Paulino-Roesler (PPR) potential based cohesive model (J Mech Phys Solids, 2009;57:891-908) is employed, and interface elements are implemented in a finite element com-mercial code. A study on the influence of the cohesive properties (i.e. cohesive strength, fracture energy, shape parameter and slope indicator) on the predicted peel-force versus displacement plots reveals that the numerical results are mostly sensitive to cohesive strength and fracture energy. In turn, these parameters are tuned until a match between experimental and simulated load displacement curves is achieved.

Simulation of debonding in Al/epoxy T-peel joints using a potential-based cohesive zone model

KAUST Repository

Alfano, Marco; Furgiuele, Franco; Lubineau, Gilles; Paulino, Glaucio H.

2011-01-01

In this work, a cohesive zone model of fracture is employed to study debonding in plastically deforming Al/epoxy T-peel joints. In order to model the adhesion between the bonded metal strips, the Park-Paulino-Roesler (PPR) potential based cohesive model (J Mech Phys Solids, 2009;57:891-908) is employed, and interface elements are implemented in a finite element com-mercial code. A study on the influence of the cohesive properties (i.e. cohesive strength, fracture energy, shape parameter and slope indicator) on the predicted peel-force versus displacement plots reveals that the numerical results are mostly sensitive to cohesive strength and fracture energy. In turn, these parameters are tuned until a match between experimental and simulated load displacement curves is achieved.

The effect of coarse gravel on cohesive sediment entrapment in an annular flume

Directory of Open Access Journals (Sweden)

K. Glasbergen

2015-03-01

Full Text Available While cohesive sediment generally represents a small fraction (16 Pa, cohesive materials trapped within the gravel bed will be entrained and transported into the Glenmore Reservoir, where sediment-associated nutrients may pose treatment challenges to the drinking water supply.

Sister broods in the spruce bark beetle, Ips typographus (L.)

Czech Academy of Sciences Publication Activity Database

Davídková, Markéta; Doležal, Petr

2017-01-01

Roč. 405, DEC 01 (2017), s. 13-21 ISSN 0378-1127 Grant - others:Lesy ČR(CZ) 08/2009-2015 Institutional support: RVO:60077344 Keywords : re-emergence * sister broods * Ips typographus Subject RIV: EH - Ecology, Behaviour OBOR OECD: Zoology Impact factor: 3.064, year: 2016 http://www.sciencedirect.com/science/article/pii/S0378112717309507

Numerical model of glulam beam delamination in dependence on cohesive strength

Science.gov (United States)

Kawecki, Bartosz; Podgórski, Jerzy

2018-01-01

This paper presents an attempt of using a finite element method for predicting delamination of a glue laminated timber beam through a cohesive layer. There were used cohesive finite elements, quadratic stress damage initiation criterion and mixed mode energy release rate failure model. Finite element damage was equal to its complete stiffness degradation. Timber material was considered to be an orthotropic with plastic behaviour after reaching bending limit.

A cohesive zone framework for environmentally assisted fatigue

DEFF Research Database (Denmark)

del Busto, Susana; Betegón, Covadonga; Martínez Pañeda, Emilio

2017-01-01

We present a compelling finite element framework to model hydrogen assisted fatigue by means of a hydrogen- and cycle-dependent cohesive zone formulation. The model builds upon: (i) appropriate environmental boundary conditions, (ii) a coupled mechanical and hydrogen diffusion response, driven...... by chemical potential gradients, (iii) a mechanical behavior characterized by finite deformation J2 plasticity, (iv) a phenomenological trapping model, (v) an irreversible cohesive zone formulation for fatigue, grounded on continuum damage mechanics, and (vi) a traction-separation law dependent on hydrogen...... coverage calculated from first principles. The computations show that the present scheme appropriately captures the main experimental trends; namely, the sensitivity of fatigue crack growth rates to the loading frequency and the environment. The role of yield strength, work hardening, and constraint...

Regions and the Territorial Cohesion

Directory of Open Access Journals (Sweden)

Ioan Ianos

2013-08-01

Full Text Available Territorial cohesion is an important target of European Union, constantly promoted by its institutions and their representatives. In the context of the Europe 2020 strategy, one of the most important support documents, the region represents a very important issue, being considered to be the key to its successfulness. The region is seen as a support for the smart growth and all the operational policy concepts try to make use of the spatial potential, by taking better account of the territorial specificities. Two main questions play attention: the need to transform the present-day developmental regions into administrative ones is a priority? What kind of regionalization it must to be promoted? Correlating these issues with already defined territorial cohesion, the administrative region is a real tool for the future territorial development. The experience of the last 14 years asks urgently the building of a new territorial administrative reform, giving competences to regions. For instant, each development region is a construction resulted from a free association of the counties. Their role in the regional development is much reduced one, because their regional councils are not elected; decisions taken at this level are consultative for the social, economical, cultural or political actors.

Phylogenetic conservatism of thermal traits explains dispersal limitation and genomic differentiation of Streptomyces sister-taxa.

Science.gov (United States)

Choudoir, Mallory J; Buckley, Daniel H

2018-06-07

The latitudinal diversity gradient is a pattern of biogeography observed broadly in plants and animals but largely undocumented in terrestrial microbial systems. Although patterns of microbial biogeography across broad taxonomic scales have been described in a range of contexts, the mechanisms that generate biogeographic patterns between closely related taxa remain incompletely characterized. Adaptive processes are a major driver of microbial biogeography, but there is less understanding of how microbial biogeography and diversification are shaped by dispersal limitation and drift. We recently described a latitudinal diversity gradient of species richness and intraspecific genetic diversity in Streptomyces by using a geographically explicit culture collection. Within this geographically explicit culture collection, we have identified Streptomyces sister-taxa whose geographic distribution is delimited by latitude. These sister-taxa differ in geographic distribution, genomic diversity, and ecological traits despite having nearly identical SSU rRNA gene sequences. Comparative genomic analysis reveals genomic differentiation of these sister-taxa consistent with restricted gene flow across latitude. Furthermore, we show phylogenetic conservatism of thermal traits between the sister-taxa suggesting that thermal trait adaptation limits dispersal and gene flow across climate regimes as defined by latitude. Such phylogenetic conservatism of thermal traits is commonly associated with latitudinal diversity gradients for plants and animals. These data provide further support for the hypothesis that the Streptomyces latitudinal diversity gradient was formed as a result of historical demographic processes defined by dispersal limitation and driven by paleoclimate dynamics.

Team cohesion and ethnic-cultural identity in adolescent migrant athletes

DEFF Research Database (Denmark)

Morela, Eleftheria; Hatzigeorgiadis, Antonis; Kouli, Olga

2013-01-01

The purpose of this study was to examine the role of sport participation in the social integration of adolescents with non-dominant ethnic and cultural backgrounds. In particular, this study investigated the relationship between team cohesion and ethnic-cultural identity. Participants were 83 young...... migrant athletes (mean age 15.60 years). Participants completed the Ethnic/Cultural Identity Salience Questionnaire and the Youth Sport Environment Questionnaire. Regression analyses showed that cohesion negatively predicted feelings of fringe and lack of interaction. Our findings suggest that sport...

Spilling over: Partner parenting stress as a predictor of family cohesion in parents of adolescents with developmental disabilities.

Science.gov (United States)

Mitchell, Darcy B; Szczerepa, Alexandra; Hauser-Cram, Penny

2016-01-01

Family cohesion relates to positive outcomes for both parents and children. Maintaining cohesion may be especially challenging for families of adolescents with developmental disabilities, yet this has been studied infrequently in this group. We investigated cohesion in these families, particularly with respect to partner stress, using the notion of the 'spillover effect' as a model. Adolescents with disabilities and their parents participated. Parents reported on teen adaptive and problem behaviours and on marital satisfaction, parenting stress, and family cohesion. The stress of one partner was tested as a predictor of the quality of family cohesion reported by the other. Adolescent behaviour problems were negative predictors of family cohesion in mothers, and marital satisfaction positively predicted cohesion for both parents. Above other factors, greater partner stress predicted poorer family cohesion for both fathers and mothers. Marital satisfaction acted as a suppressor of this relation. To improve the overall climate of families, care providers should take into consideration individual relationships, including the marital relationship. In addition, the possibility of spillover from one individual to another should be recognized as a factor in family functioning. Family-centred practices are likely to lead to greater feelings of cohesion and overall better individual and family well-being. Copyright © 2015 Elsevier Ltd. All rights reserved.

Outdoor activities and depressive symptoms in displaced older adults following natural disaster: community cohesion as mediator and moderator.

Science.gov (United States)

Chao, Shiau-Fang

2016-09-01

This investigation examined whether community cohesion mediates or moderates the relationship between outdoor activities and depressive symptoms in older adults displaced by Typhoon Morakot in Taiwan. This cross-sectional study included 292 adults aged 65 years or older who were relocated to permanent houses after Typhoon Morakot damaged their homes on 8th August 2009. Multiple regression analysis was applied to test the role of community cohesion on the association between outdoor activities and depressive symptoms. The sample of displaced older adults displayed higher prevalence of depressive symptoms than the average for community dwelling older people in Taiwan. Community cohesion fully mediated the relationship between outdoor activities and depressive symptoms. Community cohesion also moderated the relationship between outdoor activities and depressive symptoms. Community cohesion occupies a key role on the link between outdoor activities and depressive symptoms. Participation in outdoor activities was associated positively with community cohesion, while high community cohesion was related negatively to depressive symptoms. Additionally, the benefit of outdoor activities to fewer depressive symptoms only manifested in older adults with high community cohesion. Programs and services should be designed to enhance community cohesion in order to maximize the benefit of outdoor activities to the mental health of displaced older adults after natural disasters.

The effect of coarse gravel on cohesive sediment entrapment in an annular flume

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Glasbergen, K.; Stone, M.; Krishnappan, B.; Dixon, J.; Silins, U.

2015-03-01

While cohesive sediment generally represents a small fraction (armour layer of the gravel bed (>16 Pa), cohesive materials trapped within the gravel bed will be entrained and transported into the Glenmore Reservoir, where sediment-associated nutrients may pose treatment challenges to the drinking water supply.

How to deal with legal uncertainty: Managing and Audit Authorities in Cohesion Policy

NARCIS (Netherlands)

Meuleman, Lysette; Brenninkmeijer, A.F.M.

2017-01-01

Cohesion policy (ERDF, ESF and CF) is implemented in a system of shared management. Signals received from some EU countries indicate that legal uncertainty is created for beneficiaries of cohesion policy funds due to differences in interpretation of, mostly national, regulation. This is a problem

Metabolic syndrome, hypertension, and hyperlipidemia in mothers, fathers, sisters, and brothers of women with polycystic ovary syndrome: a systematic review and meta-analysis.

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Yilmaz, Bulent; Vellanki, Priyathama; Ata, Baris; Yildiz, Bulent Okan

2018-02-01

To provide an evidence-based assessment of metabolic syndrome, hypertension, and hyperlipidemia in first-degree relatives of women with polycystic ovary syndrome (PCOS). Systematic review and meta-analysis. Not applicable. Mothers, fathers, sisters, and brothers of women with and without PCOS. An electronic-based search with the use of PubMed from 1960 to June 2015 and cross-checked references of relevant articles. Metabolic syndrome, hypertension and dyslipidemia, and surrogate markers, including systolic blood pressure (BP), diastolic BP, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides. Fourteen of 3,346 studies were included in the meta-analysis. Prevalence of the following was significantly increased in relatives of women with PCOS: metabolic syndrome (risk ratio [RR] 1.78 [95% confidence interval 1.37, 2.30] in mothers, 1.43 [1.12, 1.81] in fathers, and 1.50 [1.12, 2.00] in sisters), hypertension (RR 1.93 [1.58, 2.35] in fathers, 2.92 [1.92, 4.45] in sisters), and dyslipidemia (RR 3.86 [2.54, 5.85] in brothers and 1.29 [1.11, 1.50] in fathers). Moreover, systolic BP (mothers, sisters, and brothers), total cholesterol (mothers and sisters), low-density lipoprotein cholesterol (sisters), and triglycerides (mothers and sisters) were significantly higher in first-degree relatives of PCOS probands than in controls. Our results show evidence of clustering for metabolic syndrome, hypertension, and dyslipidemia in mothers, fathers, sisters, and brothers of women with PCOS. PROSPERO 2016 CRD42016048557. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Group Cohesion in Experiential Growth Groups

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Steen, Sam; Vasserman-Stokes, Elaina; Vannatta, Rachel

2014-01-01

This article explores the effect of web-based journaling on changes in group cohesion within experiential growth groups. Master's students were divided into 2 groups. Both used a web-based platform to journal after each session; however, only 1 of the groups was able to read each other's journals. Quantitative data collected before and…

[Team cohesiveness: opinions of a group of primary health care professionals from Salamanca].

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González, F J; de Cabo, A; Morán, M J; Manzano, J M

1993-04-01

To assess the view of a group of Primary care professionals on their level of perception of group cohesiveness in their teams' work dynamic. A descriptive and sectional study. Four urban health centres in Salamanca with a recognised teaching activity. Both health professionals and those outside the Health Service, working in Primary Care, who had been members of their teams for more than a year (N = 90). Descriptive statistics and "Chi squared" tests were employed. 72%. A high level of agreement on the need for team work (95.23%). They perceived their group cohesiveness as being very low (84.21% affirmed that they encounter problems of cohesiveness). The main statements concerning this lack of cohesiveness were: "lack of common objectives" (25.5%), "intolerance between workers" (20.13%), "work not shared" (19.46%) and "the taking of decisions individually" (19.44%). The main causes given were: lack of support from Management (23.74%) and too little training for team work (21.58%). There is a high degree of conviction that the team work model is the most efficacious way of developing Primary Care. However in three of the four teams questioned, there were serious problems preventing the teams' reaching an adequate level of group cohesiveness.

The use of convent archival records in medical research: the School Sisters of Notre Dame archives and the nun study.

Science.gov (United States)

Patzwald, Gari-Anne; Wildt, Sister Carol Marie

2004-01-01

The School Sisters of Notre Dame (SSND) archives program in a cooperative system for the arrangement and preservation of the records of the SSND provinces in North America, including records of individual sisters. Archival records include autobiographies, school and college transcripts, employment histories, and family socioeconomic data. The Nun Study, a longitudinal study of Alzheimer's disease and aging in 678 SSND sisters, compares data extracted from these records with data on late-life cognitive and physical function and postmortem brain neuropathology to explore early life factor that may affect late-life cognitive function and longevity.

The Process Architecture of EU Territorial Cohesion Policy

Directory of Open Access Journals (Sweden)

Andreas Faludi

2010-08-01

Full Text Available When preparing the European Spatial Development Perspective (ESDP, Member States were supported by the European Commission but denied the EU a competence in the matter. Currently, the Treaty of Lisbon identifies territorial cohesion as a competence shared between the Union and the Member States. This paper is about the process architecture of territorial cohesion policy. In the past, this architecture resembled the Open Method of Coordination (OMC which the White Paper on European Governance praised, but only in areas where there was no EU competence. This reflected zero-sum thinking which may continue even under the Lisbon Treaty. After all, for as long as territorial cohesion was not a competence, voluntary cooperation as practiced in the ESDP process was pursued in this way. However, the practice of EU policies, even in areas where there is an EU competence, often exhibits features of the OMC. Surprisingly effective innovations hold the promise of rendering institutions of decision making comprehensible and democratically accountable. In the EU as a functioning polity decision making is thus at least part deliberative so that actors’ preferences are transformed by the force of the better argument. This brings into focus the socialisation of the deliberators into epistemic communities. Largely an informal process, this is reminiscent of European spatial planning having been characterised as a learning process.

The Role of Lexical Cohesion in Writing Quality

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Hmoud Alotaibi

2015-01-01

Full Text Available The idea of whether repetition has any relation with the writing quality of the text has remained an issue that intrigues a number of scholars in linguistics and in writing studies. Michael Hoey (1991, Halliday and Hasan (1976 are two prominent works in presenting detailed and thoughtful analysis of repetition occurrences in the text. This study uses a model of lexical cohesion proposed by Witte and Faigley (1981 which itself is based on the taxonomies of cohesive ties presented by Halliday and Hasan (1976.  The model deals with lexical cohesion and its subclasses, namely, repetition (same type, synonym, near-synonym, super-ordinate item, and general item and collocation. The corpus includes five argumentative essays written by students in the field of English language literature. Five teaching assistants were asked to rank the papers on a five-point scale based on their perception of the papers’ writing quality. The results showed that the paper that received the lowest rating in terms of the writing quality was the one that included the largest number of repetition occurrences of the same type. The study concludes by arguing that repetition may not be considered as monolithic, and suggests that every type of repetition needs to be examined individually in order to determine what enhances and what deteriorates the writing quality.

Slow stress relaxation behavior of cohesive powders

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Imole, Olukayode Isaiah; Paulick, Maria; Magnanimo, Vanessa; Morgenmeyer, Martin; Ramaioli, Marco; Chavez Montes, Bruno E.; Kwade, Arno; Luding, Stefan

2016-01-01

We present uniaxial (oedometric) compression tests on two cohesive industrially relevant granular materials (cocoa and limestone powder). A comprehensive set of experiments is performed using two devices – the FT4 Powder Rheometer and the custom made lambdameter – in order to investigate the