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Sample records for high-frequency deletion polymorphisms

  1. Total alpha-globin gene cluster deletion has high frequency in Filipinos

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, J.A.; Haruyama, A.Z.; Chu, B.M. [Kapiolani Medical Center, Honolulu, HI (United States)] [and others

    1994-09-01

    Most {alpha}-thalassemias [Thal] are due to large deletions. In Southeast Asians, the (--{sup SEA}) double {alpha}-globin gene deletion is common, 3 (--{sup Tot}) total {alpha}-globin cluster deletions are known: Filipino (--{sup Fil}), Thai (--{sup Thai}), and Chinese (--{sup Chin}). In a Hawaii Thal project, provisional diagnosis of {alpha}-Thal-1 heterozygotes was based on microcytosis, normal isoelectric focusing, and no iron deficiency. One in 10 unselected Filipinos was an {alpha}-Thal-1 heterozygote, 2/3 of these had a (--{sup Tot}) deletion: a {var_sigma}-cDNA probe consistently showed fainter intensity of the constant 5.5 kb {var_sigma}{sub 2} BamHI band, with no heterzygosity for {var_sigma}-globin region polymorphisms; {alpha}-cDNA or {var_sigma}-cDNA probes showed no BamHI or BglII bands diagnostic of the (--{sup SEA}) deletion; bands for the (-{alpha}) {alpha}-Thal-2 single {alpha}-globin deletions were only seen in Hb H cases. A reliable monoclonal anti-{var_sigma}-peptide antibody test for the (--{sup SEA}) deletion was always negative in (--{sup Tot}) samples. Southern digests with the Lo probe, a gift from D. Higgs of Oxford Univ., confirmed that 49 of 50 (--{sup Tot}) chromosomes in Filipinos were (--{sup Fil}). Of 20 {alpha}-Thal-1 hydrops born to Filipinos, 11 were (--{sup Fil}/--{sup SEA}) compound heterozygotes; 9 were (--{sup SEA}/--{sup SEA}) homozygotes, but none was a (--{sup Fil}/--{sup Fil}).

  2. Total beta-globin gene deletion has high frequency in Filipinos

    Energy Technology Data Exchange (ETDEWEB)

    Patrick, N.; Miyakawa, F.; Hunt, J.A. [Univ. of Hawaii, Honolulu, HI (United States)] [and others

    1994-09-01

    The distribution of {beta}-thalassemia [{beta}{sup Th}] mutations is unique to each ethnic group. Most mutations affect one or a few bases; large deletions have been rare. Among families screened in Hawaii, [{beta}{sup Th}] heterozygotes were diagnosed by microcytosis, absence of abnormal hemoglobins on isoelectric focusing, and raised Hb A{sub 2} by chromatography. Gene frequency for {beta}{sup Th} was 0.02 in Filipinos. In Filipinos, polymerase chain reaction [PCR] with denaturing gradient gel electrophoresis for {beta}{sup Th} mutations detected a mutation in only 6 of 42 {beta}{sup Th} heterozygotes; an IVS2-666 C/T polymorphism showed non-heterozygosity in 37 and heterozygosity in only 5 of these {beta}{sup Th} heterozygotes. One {beta}{sup Th}/{beta}{sup Th} major patient and his mother had no mutation detected by allele-specific oligomer hybridization; PCR failed to amplify any DNA from his {beta}-globin gene. After a total {beta}-globin gene deletion [{beta}{sup Del}] was found in a Filipino family in Ontario, specific PCR amplification for {beta}{sup Del} detected this in 43 of 53 {beta}{sup Th} Filipino samples tested; the above {beta}{sup Th}/{beta}{sup Th} patient was a ({beta}{sup Del}/{beta}{sup Del}) homozygote. The {beta}{sup Del} may account for over 60% of all {beta}{sup Th} alleles in Filipinos; this is the highest proportion of a deletion {beta}{sup Th} mutation reported from any population. Most but not all {beta}{sup Del} heterozygotes had high Hb F [5.13 {plus_minus} 3.94 mean {plus_minus} 1 s.d.] compared to the codon 41/42 four base deletion common in Chinese [2.30 {plus_minus} 0.86], or to {beta}{sup Th} heterozygotes with normal {alpha}-globin genes [2.23 {plus_minus} 0.80].

  3. Lack of association of insertion/deletion polymorphism in ...

    African Journals Online (AJOL)

    In the present preliminary study the insertion/deletion polymorphism within angiotensin converting enzyme gene is not likely to be associated with nephropathy in type 2 diabetic patients of Punjabi population of Pakistan. Key words: Angiotensin converting enzymes, insertion/deletion polymorphism, albuminuria and type 2 ...

  4. Fluconazole induces rapid high-frequency MTL homozygosis with microbiological polymorphism in Candida albicans

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    Tsong-Yih Ou

    2017-12-01

    Full Text Available Background: Candida albicans, a common fungal pathogen that can cause opportunistic infections, is regarded as an apparently asexual, diploid fungus. A parasexual cycle was previously found between homozygotes with opposite mating type-like loci (MTLa/α. Fluconazole-resistant strains had a higher proportion of MTL homozygotes, whereas MTL homozygous C. albicans was found in only about 3.2% of clinical strains. MTL heterozygotes had a low frequency (1.4 × 10−4 of white–opaque switching to MTL homozygotes in nature. Methods: Here, a reference C. albicans strain (SC5314 was used in a fluconazole-induced assay to obtain standard opaque MTL homozygous strains and first-generation daughter strains from the fluconazole inhibition zone. Further separation methods were employed to produce second- and third-generation daughter strains. Polymerase chain reaction analysis based on MTL genes was used to define MTL genotypes, and microscopic observations, a flow-cytometric assay, and an antifungal E-test were used to compare microbiological characteristics. Results: MTL homozygotes were found at a high frequency (17 of 35; 48.6% in fluconazole-induced first-generation daughter strains, as were morphological polymorphisms, decreased DNA content, and modified antifungal drug susceptibility. High-frequency MTL homozygosity was identified inside the fluconazole inhibition zone within 24 hours. The DNA content of fluconazole-induced daughter strains was reduced compared with their progenitor SC5314 and standard MTL homozygous strains. Conclusion: Treatment with fluconazole, commonly used to treat invasive candidiasis, inhibited the growth of C. albicans and altered its microbiological characteristics. Our results suggest that fluconazole treatment induces the high frequency of loss of heterozygosity and microbiological polymorphism in C. albicans. Keywords: Candida albicans, fluconazole, loss of heterozygosity, mating type-like gene

  5. Lack of Association of Insertion/Deletion Polymorphism in ...

    African Journals Online (AJOL)

    DRNAQSHAB

    2012-01-19

    Jan 19, 2012 ... Key words: Angiotensin converting enzymes, insertion/deletion polymorphism, albuminuria and type 2 diabetes mellitus. INTRODUCTION. Diabetic nephropathy is a leading cause of diabetic. *Corresponding author. E-mail: naeemrashid37@hotmail.com, naeem.ff.sbs@pu.edu.pk. Tel: +92 42 99231534.

  6. Association of insertion–deletion polymorphism of ACE gene and ...

    African Journals Online (AJOL)

    Introduction: Alzheimer's disease (AD) is a progressive, neurodegenerative disease. Many studies proposed an association of the insertion (I)/deletion (D) polymorphism (indel) in intron 16 of the gene for angiotensin I-converting enzyme (ACE) on chromosome 17q23 with Alzheimer's disease. ACE indel and related ...

  7. Angiotensin-converting enzyme gene (ACE) insertion/deletion polymorphism in Mexican populations.

    Science.gov (United States)

    Vargas-Alarcón, Gilberto; Hernández-Pacheco, Guadalupe; Rodríguez-Pérez, José Manuel; Pérez-Hernández, Nonanzit; Pavón, Zinnia; Fragoso, José Manuel; Juarez-Cedillo, Teresa; Villarreal-Garza, Cynthia; Granados, Julio

    2003-12-01

    The angiotensin-converting enzyme gene (ACE) insertion/deletion polymorphism was determined in 211 Mexican healthy individuals belonging to different Mexican ethnic groups (98 Mestizos, 64 Teenek, and 49 Nahuas). ACE polymorphism differed among Mexicans with a high frequency of the D allele and the D/D genotype in Mexican Mestizos. The D/D genotype was absent in Teenek and present in only one Nahua individual (2.0%). When comparisons were made, we observed that Caucasian, African, and Asian populations presented the highest frequencies of the D allele, whereas Amerindian (Teenek and Pima) and Australian Aboriginals showed the highest frequencies of the I allele. The distribution of I/D genotype was heterogeneous in all populations: Australian Aboriginals presented the lowest frequency (4.9%), whereas Nahuas presented the highest (73.4%). The present study shows the frequencies of a polymorphism not analyzed previously in Mexican populations and establishes that this polymorphism distinguishes the Amerindian populations of other groups. On the other hand, since ACE alleles have been associated with genetic susceptibility to developing cardiovascular diseases and hypertension, knowledge of the distribution of these alleles could help to define the true significance of ACE polymorphism as a genetic susceptibility marker in the Amerindian populations.

  8. Population stratification of a common APOBEC gene deletion polymorphism.

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    Jeffrey M Kidd

    2007-04-01

    Full Text Available The APOBEC3 gene family plays a role in innate cellular immunity inhibiting retroviral infection, hepatitis B virus propagation, and the retrotransposition of endogenous elements. We present a detailed sequence and population genetic analysis of a 29.5-kb common human deletion polymorphism that removes the APOBEC3B gene. We developed a PCR-based genotyping assay, characterized 1,277 human diversity samples, and found that the frequency of the deletion allele varies significantly among major continental groups (global FST = 0.2843. The deletion is rare in Africans and Europeans (frequency of 0.9% and 6%, more common in East Asians and Amerindians (36.9% and 57.7%, and almost fixed in Oceanic populations (92.9%. Despite a worldwide frequency of 22.5%, analysis of data from the International HapMap Project reveals that no single existing tag single nucleotide polymorphism may serve as a surrogate for the deletion variant, emphasizing that without careful analysis its phenotypic impact may be overlooked in association studies. Application of haplotype-based tests for selection revealed potential pitfalls in the direct application of existing methods to the analysis of genomic structural variation. These data emphasize the importance of directly genotyping structural variation in association studies and of accurately resolving variant breakpoints before proceeding with more detailed population-genetic analysis.

  9. A 660-Kb deletion with antagonistic effects on fertility and milk production segregates at high frequency in Nordic Red cattle

    DEFF Research Database (Denmark)

    Kadri, Naveen Kumar; Sahana, Goutam; Charlier, Carole

    2014-01-01

    to the negative energy balance of high-producing cows at the peak of lactation. We herein describe the fine-mapping of a major fertility QTL in Nordic Red cattle, and identify a 660-kb deletion encompassing four genes as the causative variant. We show that the deletion is a recessive embryonically lethal mutation....... This probably results from the loss of RNASEH2B, which is known to cause embryonic death in mice. Despite its dramatic effect on fertility, 13%, 23% and 32% of the animals carry the deletion in Danish, Swedish and Finnish Red Cattle, respectively. To explain this, we searched for favorable effects on other...... traits and found that the deletion has strong positive effects on milk yield. This study demonstrates that embryonic lethal mutations account for a non-negligible fraction of the decline in fertility of domestic cattle, and that associated positive effects on milk yield may account for part...

  10. A 660-Kb Deletion with Antagonistic Effects on Fertility and Milk Production Segregates at High Frequency in Nordic Red Cattle

    DEFF Research Database (Denmark)

    Kadri, Naveen Kumar; Sahana, Goutam; Charlier, Carole

    The spectacular increase in productivity of dairy cattle has been accompanied by a decline in fertility. It is assumed that this reduction is due to the negative energy balance of high producing cows. We herein describe the dissection of a fertility QTL in Nordic Red cattle to a 660-Kb deletion...

  11. Insertions/deletions-associated nucleotide polymorphism in Arabidopsis thaliana

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    Changjiang Guo

    2016-11-01

    Full Text Available Although high levels of within-species variation are commonly observed, a general mechanism for the origin of such variation is still lacking. Insertions and deletions (indels are a widespread feature of genomes and we hypothesize that there might be an association between indels and patterns of nucleotide polymorphism. Here, we investigate flanking sequences around 18 indels (>100bp among a large number of accessions of the plant, Arabidopsis thaliana. We found two distinct haplotypes, i.e. a nucleotide dimorphism, present around each of these indels and dimorphic haplotypes always corresponded to the indel-present/-absent patterns. In addition, the peaks of nucleotide diversity between the two divergent alleles were closely associated with these indels. Thus, there exists a close association between indels and dimorphisms. Further analysis suggests that indel-associated substitutions could be an important component of genetic variation shaping nucleotide polymorphism in Arabidopsis. Finally, we suggest a mechanism by which indels might generate these highly divergent haplotypes. This study provides evidence that nucleotide dimorphisms, which are frequently regarded as evidence of frequency-dependent selection, could be explained simply by structural variation in the genome.

  12. Angiotensin-converting enzyme insertion/deletion polymorphism ...

    African Journals Online (AJOL)

    Background: The angiotensin-converting enzyme (ACE) I/D polymorphism has been reported to be associated with Kawasaki disease(KD) ,but studies to date present conflicting results. Objectives: The aim of this study is to derive a more precise estimation of the association between the ACE I/D polymorphism and KD risk.

  13. Deletion polymorphism at chromosome 3q26.1 and oral squamous cell carcinoma

    Science.gov (United States)

    KAWACHI, HOMARE; SUGAHARA, KEISUKE; NAKAMURA, YASUTAKA; KATAKURA, AKIRA; MINAGUCHI, KIYOSHI; SHIBAHARA, TAKAHIKO

    2013-01-01

    Several recent studies have investigated DNA instability in malignancies including deletions and duplications of part of the chromosome using array-based comparative genomic hybridization (CGH) analysis. Using the same approach on oral squamous cell carcinoma (OSCC) tissue samples, we found a frequent deletion at chromosome 3q26.1 in OSCC patients; this polymorphism showed a gene frequency of 0.293–0.368 in healthy volunteers (n=60) and 0.129–0.195 in OSCC patients (n=54). Detailed analysis around the polymorphic region revealed the deletion breakage point. A significant association of gene frequency for the deletion polymorphism between healthy volunteers and patients implicated genetic factors related to this polymorphism in the development of OSCC. Currently, no gene is predicted to lie within the 3,606-kbp region around the polymorphism. Thus, although a single-gene model could not explain the occurrence of OSCC, we believe that examining this polymorphism could be useful in identifying risk factors for OSCC. PMID:23258604

  14. The insertion/deletion polymorphism of angiotensin-converting ...

    African Journals Online (AJOL)

    The association between type 2 diabetes mellitus (T2DM) and essential hypertension (EH) is not well understood. Both conditions result from an interaction of multiple genetic (ethnic) and environmental (geographical) factors. One possible genetic determinant is the angiotensin-converting enzyme (ACE) insertion/deletion ...

  15. A method for the analysis of 32 X chromosome insertion deletion polymorphisms in a single PCR

    DEFF Research Database (Denmark)

    Pereira, Rui; Pereira, Vania; Gomes, Iva

    2012-01-01

    Studies of human genetic variation predominantly use short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs) but Insertion deletion polymorphisms (Indels) are being increasingly explored. They combine desirable characteristics of other genetic markers, especially the possibility of....... Finally, a segregation analysis was performed using trio constellations of father-mother-daughters in order to address the transmission pattern and assess mutation rates of this type of markers....

  16. A rapid detection method for PAI-1 promoter insertion/deletion polymorphism (4G/5G

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    Annichino-Bizzacchi Joyce M.

    1998-01-01

    Full Text Available Plasminogen activator inhibitor-1 (PAI-1 is an important inhibitor of fibrinolysis, and increased levels of PAI-1 are associated with atheroma and myocardial infarction. A common 4G/5G insertion/deletion polymorphism located in the promoter region of PAI-1 gene has been described associated with PAI-1 activity in plasma levels. Genotyping of this polymorphism is commonly conducted with an allele-specific oligonucleotide melting technique. In the present study, we describe a quick, easy method for genotyping 4G/5G polymorphism in the promoter region of the PAI-1 gene.

  17. Insertion/deletion polymorphism of the ACE gene and adherence to ACE inhibitors

    NARCIS (Netherlands)

    H. Schelleman (Hedi); O.H. Klungel (Olaf); C.M. van Duijn (Cornelia); J.C.M. Witteman (Jacqueline); A. Hofman (Albert); A.C. de Boer (Anthonius); B.H.Ch. Stricker (Bruno)

    2005-01-01

    textabstractAims: We investigated whether the insertion/deletion (I/D) polymorphism of the ACE gene modified the adherence to ACE inhibitors as measured by the discontinuation of an ACE inhibitor, or addition of another antihypertensive drug. Methods: This was a cohort study among 239 subjects who

  18. deletion polymorphism of ACE gene and Alzheimerв€™s disease

    African Journals Online (AJOL)

    Omayma M. Hassanin

    2014-06-27

    Jun 27, 2014 ... Abstract Introduction: Alzheimer's disease (AD) is a progressive, neurodegenerative disease. Many studies proposed an association of the insertion (I)/deletion (D) polymorphism (indel) in intron 16 of the gene for angiotensin I-converting enzyme (ACE) on chromosome 17q23 with Alz- heimer's disease.

  19. APOBEC3 deletion polymorphism is associated with breast cancer risk among women of European ancestry.

    Science.gov (United States)

    Xuan, Dennis; Li, Guoliang; Cai, Qiuyin; Deming-Halverson, Sandra; Shrubsole, Martha J; Shu, Xiao-Ou; Kelley, Mark C; Zheng, Wei; Long, Jirong

    2013-10-01

    Copy number variations occur frequently in the genome and are a significant source of human genetic variation accounting for disease. Recently, we discovered a common deletion located in the APOBEC3A and APOBEC3B genes significantly associated with breast cancer in Chinese women. Investigating this locus in other populations would be an expedient way to evaluate the generalizability of the novel finding. We analyzed the APOBEC3 deletion in a large study of 3273 European-ancestry women (including 1671 breast cancer cases and 1602 controls) from the population-based Nashville Breast Health Study. All participants were genotyped using real-time qualitative PCR. Logistic regression was used to derive odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between the deletion polymorphism and breast cancer risk. The APOBEC3 deletion was observed in 12.4% of cases and 10.4% of controls. The deletion was significantly associated with breast cancer risk, with ORs and 95% CIs of 1.21 (1.02-1.43) associated with one-copy deletion and 2.29 (1.04-5.06) associated with two-copy deletion compared with women with no deletion (P for trend = 0.005). The positive association of the APOBEC3 deletion with breast cancer risk was similar for estrogen receptor-positive and estrogen receptor-negative breast cancer and was not modified by known breast cancer risk factors. Results from this study confirmed the association of the APOBEC3 deletion with breast cancer risk among women of European ancestry.

  20. Analysis of the STS gene in 40 patients with recessive X-linked ichthyosis: a high frequency of partial deletions in a Spanish population.

    Science.gov (United States)

    Cañueto, J; Ciria, S; Hernández-Martín, A; Unamuno, P; González-Sarmiento, R

    2010-10-01

    Recessive X-linked ichthyosis (RXLI) (OMIM 308100) is a genodermatosis characterized by polygonal, dark, adherent and mild-to-moderate scales that normally improve during summer. RXLI is caused by a deficiency in steroid sulphatase (STS), whose gene has been located on the X chromosome (locus Xp22.3). Up to 90% of the mutations described in this gene are complete deletions. Previous reports of partial deletion of STS gene in cases of RXLI prompted us to determine the incidence of these abnormalities in a Spanish population. We have studied exons 1, 5 and 10 of the STS gene by polymerase chain reaction in 40 patients with clinical features of RXLI. Our results revealed that 30 patients presented complete deletions (75%) while 10 patients had partial deletions (25%) a rate higher than that reported in the previous studies. Amplification of exons 1, 5 and 10 is reliable in screening RXLI in the population studied here. No correlation was found between phenotype and the extent of the deletions.

  1. The Insertion/Deletion Polymorphism of the Angiotensin Converting Enzyme (ACE) in Parkinson’s Disease

    Science.gov (United States)

    Papapetropoulos, Spiridon; Glynos, Kostantinos; Zhou, Zongmin; Orfanos, Stylianos E; Mitsi, Georgia; Papapetropoulos, Andreas

    2008-01-01

    Parkinson’s disease (PDI is a neurodegenerative disorder of unknown etiology. Both genetic and environmental factors are thought to be implicated to some extent. The ACE gene insertion/deletion (I/D) polymorphism has been associated with common neurodegenerative disorders that share similar clinical and neuropathological features with PD (Alzheimer’s disease). In this study we set out to examine the role of the ACE gene insertion/deletion (I/D) polymorphism in Parkinson’s disease (PD). We conducted a case-control association study among 77 PD patients and 50 non-PD controls from Greece. The genotype frequencies for II, ID, and DD were 39, 48, and 13%, respectively, in the PD group and 32, 50, and 18% in the control group. Although the DD frequency was higher in the case group statistical significance was not reached. We conclude that although disease modifying effects cannot be excluded, the ACE insertion/deletion polymorphism is unlikely to be an important determinant of susceptibility to PD in this population. PMID:19452013

  2. [Unexpected discovery of a fetus with DMD gene deletion using single nucleotide polymorphism array].

    Science.gov (United States)

    Lin, Shaobin; Zhou, Yu; Zhou, Bingyi; Gu, Heng

    2017-08-10

    To investigate the value of single nucleotide polymorphism array (SNP array) for the identification of de novo mutations in the DMD gene among fetuses. G-banded karyotyping and SNP array were performed on a fetus with intrauterine growth restriction but without family history of Duchenne/Becker muscular dystrophy (DMD/BMD). Multiplex ligation-dependent probe amplification (MLPA) was subsequently applied on amniocytes and maternal peripheral blood sample to detect DMD gene deletion/duplication mutations. Karyotyping of amniocytes showed a normal 46, XY karyotype. SNP array on amniocytes detected a 116 kb deletion (chrX: 32 455 741-32 571 504) at Xp21.1 with breakpoints at introns 16 and 30 respectively, encompassing exons 17-29 of the DMD gene. In addition, MLPA analysis of the DMD gene on amniocytes confirmed the deletion of exons 17 to 29 identified by SNP array. However, no deletion/duplication mutation was detected by MLPA in the mother. The de novo deletion of exons 17 to 29 of the DMD gene detected in the fetus may result in BMD or DMD. SNP array can improve the efficiency for detecting genomic disorders in fetuses with unidentified pathogenic genes, negative family history and nonspecific phenotypes.

  3. ACE insertion/deletion polymorphism is associated with periodontal disease in Korean population.

    Science.gov (United States)

    Kang, Sang Wook; Han, Seung Yeop; Lim, Sung Bin; Cho, Kyu Bong; Ban, Ju Yeon

    2015-03-01

    Angiotensin-converting enzyme (ACE) is the core enzyme in the renin-angiotensin system (RAS), which catalyzes the production of angiotensin II (Ang II). The aim of this study was to determine whether ACE gene is associated with the development of the periodontal disease. To investigate whether ACE is involved in the development of the periodontal disease, 199 periodontal disease patients and 165 control subjects were studied. The ACE insertion/deletion polymorphism was analyzed using polymerase chain reaction (PCR). SNPStats and SPSS 18.0 were used for the analysis of genetic data. Logistic regression models were performed to determine odds ratio (OR), 95% confidence interval (CI), and P value. Genotypic frequencies of I/I, I/D, and D/D were 25.4%, 42.3%, and 32.3% vs. 35.3%, 41.7%, and 23.1% (periodontal disease group vs. control group), respectively. In the genotype analysis of the ACE insertion/deletion polymorphism, codominant and log-additive models both showed significant association with periodontal disease [OR = 1.94, 95% CI = 1.05-3.61, P=0.036 in the codominant model (I/I vs. D/D); OR = 1.39, 95% CI = 1.02-1.90, P = 0.034 in the log-additive model (I/I vs. I/D vs. D/D)]. These results suggest that the ACE insertion/deletion polymorphism may be associated with the susceptibility to the periodontal disease in the Korean population. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Association between migraine and ACE gene (insertion/deletion) polymorphism: the BioBIM study.

    Science.gov (United States)

    Palmirotta, Raffaele; Barbanti, Piero; Ludovici, Giorgia; De Marchis, Maria Laura; Ialongo, Cristiano; Egeo, Gabriella; Aurilia, Cinzia; Fofi, Luisa; Abete, Pasquale; Spila, Antonella; Ferroni, Patrizia; Della-Morte, David; Guadagni, Fiorella

    2014-02-01

    In the present case-control study, we investigated the correlation between the common ACE insertion/deletion (I/D) polymorphism and migraine. Genotyping of the ACE I/D variant was performed in 502 Caucasian patients with migraine and 323 age-, sex- and race/ethnicity-matched healthy controls. We investigated associations between ACE genetic variants and sociodemographic and/or clinical features of migraineurs. We found a significant association between ACE insertion/insertion (I/I) polymorphism and lower use of pharmacological prophylaxis in migraine patients with aura and in those with chronic migraine. Moreover, ACE I/I polymorphism was significantly more common in migraine patients with aura who had a negative family history of migraine. Our data suggest that although the ACE I/D polymorphism is not a direct risk factor for migraine, the ACE I/I genotype may influence the clinical feature of this disease being associated with reduced use of prophylactic agents in patients with migraine with aura and in those with chronic migraine.

  5. Insertion-deletion polymorphisms (indels as genetic markers in natural populations

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    Johansson Malin

    2008-01-01

    Full Text Available Abstract Background We introduce the use of short insertion-deletion polymorphisms (indels for genetic analysis of natural populations. Results Sequence reads from light shot-gun sequencing efforts of different dog breeds were aligned to the dog genome reference sequence and gaps corresponding to indels were identified. One hundred candidate markers (4-bp indels were selected and genotyped in unrelated dogs (n = 7 and wolves (n = 18. Eighty-one and 76 out of 94 could be validated as polymorphic loci in the respective sample. Mean indel heterozygosity in a diverse set of wolves was 19%, and 74% of the loci had a minor allele frequency of >10%. Indels found to be polymorphic in wolves were subsequently genotyped in a highly bottlenecked Scandinavian wolf population. Fifty-one loci turned out to be polymorphic, showing their utility even in a population with low genetic diversity. In this population, individual heterozygosity measured at indel and microsatellite loci were highly correlated. Conclusion With an increasing amount of sequence information gathered from non-model organisms, we suggest that indels will come to form an important source of genetic markers, easy and cheap to genotype, for studies of natural populations.

  6. Angiotensin-converting-enzyme gene insertion/deletion polymorphism and response to physical training.

    Science.gov (United States)

    Montgomery, H; Clarkson, P; Barnard, M; Bell, J; Brynes, A; Dollery, C; Hajnal, J; Hemingway, H; Mercer, D; Jarman, P; Marshall, R; Prasad, K; Rayson, M; Saeed, N; Talmud, P; Thomas, L; Jubb, M; World, M; Humphries, S

    1999-02-13

    The function of local renin-angiotensin systems in skeletal muscle and adipose tissue remains largely unknown. A polymorphism of the human angiotensin converting enzyme (ACE) gene has been identified in which the insertion (I) rather than deletion (D) allele is associated with lower ACE activity in body tissues and increased response to some aspects of physical training. We studied the association between the ACE gene insertion or deletion polymorphism and changes in body composition related to an intensive exercise programme, to investigate the metabolic effects of local human renin-angiotensin systems. We used three independent methods (bioimpedance, multiple skinfold-thickness assessment of whole-body composition, magnetic resonance imaging of the mid-thigh) to study changes in body composition in young male army recruits over 10 weeks of intensive physical training. Participants with the II genotype had a greater anabolic response than those with one or more D alleles for fat mass (0.55 vs -0.20 kg, p=0.04 by bioimpedance) and non-fat mass (1.31 vs -0.15 kg, p=0.01 by bioimpedance). Changes in body morphology with training measured by the other methods were also dependent on genotype. II genotype, as a marker of low ACE activity in body tissues, may conserve a positive energy balance during rigorous training, which suggests enhanced metabolic efficiency. This finding may explain some of the survival and functional benefits of therapy with ACE inhibitors.

  7. Effects of Korean Red Ginseng and HAART on vif Gene in 10 Long-Term Slow Progressors over 20 Years: High Frequency of Deletions and G-to-A Hypermutation

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    Young Keol Cho

    2013-01-01

    Full Text Available To investigate if Korean red ginseng (KRG affects vif gene, we determined vif gene over 20 years in 10 long-term slowly progressing patients (LTSP who were treated with KRG alone and then KRG plus HAART. We also compared these data with those of 21 control patients who did not receive KRG. Control patient group harbored only one premature stop codon (PSC (0.9%, whereas the 10 LTSP revealed 78 defective genes (18.1% (P<0.001. The frequency of small in-frame deletions was found to be significantly higher in patients who received KRG alone (10.5% than 0% in the pre-KRG or control patients (P<0.01. Regarding HAART, vif genes containing PSCs were more frequently detected in patients receiving KRG plus HAART than patients receiving KRG alone or control patients (P<0.01. In conclusion, our current data suggest that the high frequency of deletions and PSC in the vif gene is associated with KRG intake and HAART, respectively.

  8. Effect of deletion polymorphism of angiotensin converting enzyme gene on progression of diabetic nephropathy during inhibition of angiotensin converting enzyme

    DEFF Research Database (Denmark)

    Parving, H H; Jacobsen, P; Tarnow, L

    1996-01-01

    showed that haemoglobin A1c concentration, albuminuria, and the double deletion genotype independently influenced the sustained rate of decline in glomerular filtration rate (R1 (adjusted) = 0.51). CONCLUSION: The deletion polymorphism in the angiotensin converting enzyme gene reduces the long term......OBJECTIVE: To evaluate the concept that an insertion/deletion polymorphism of the angiotensin converting enzyme gene predicts the therapeutic efficacy of inhibition of angiotensin converting enzyme on progression of diabetic nephropathy. DESIGN: Observational follow up study of patients...... (median 75 mg/day (range 12.5 to 150 mg/day)) that was in many cases combined with a loop diuretic, 11 patients were homozygous for the deletion allele and 24 were heterozygous or homozygous for the insertion allele of the angiotensin converting enzyme gene. MAIN OUTCOME MEASURES: Albuminuria, arterial...

  9. Deletion/insertion polymorphism of the angiotensin-converting enzyme gene and white matter hyperintensities in dementia: A pilot study.

    NARCIS (Netherlands)

    Purandare, N.; Oude Voshaar, R.C.; Davidson, Y.; Gibbons, L.; Hardicre, J.; Byrne, J.; McCollum, C.N.; Jackson, A.; Burns, A.; Mann, D.M.

    2006-01-01

    OBJECTIVES: To examine the association between the angiotensin-converting enzyme (ACE) deletion/insertion (D/I) polymorphism and white matter hyperintensities (WMHs) in patients with dementia. DESIGN: Observational pilot study with adjustment for potential confounders using analysis of covariance.

  10. Chromosome replacement and deletion lead to clonal polymorphism of berry color in grapevine.

    Directory of Open Access Journals (Sweden)

    Frédérique Pelsy

    2015-04-01

    Full Text Available Clonal polymorphism mainly results from somatic mutations that occur naturally during plant growth. In grapevine, arrays of clones have been selected within varieties as a valuable source of diversity, among them clones showing berry color polymorphism. To identify mutations responsible for this color polymorphism, we studied a collection of 33 clones of Pinot noir, Pinot gris, and Pinot blanc. Haplotypes of the L2 cell layer of nine clones were resolved by genotyping self-progenies with molecular markers along a 10.07 Mb region of chromosome 2, including the color locus. We demonstrated that at least six haplotypes could account for the loss of anthocyanin biosynthesis. Four of them resulted from the replacement of sections of the 'colored' haplotype, sized from 31 kb to 4.4 Mb, by the homologous sections of the 'white' haplotype mutated at the color locus. This transfer of information between the two homologous sequences resulted in the partial homozygosity of chromosome 2, associated in one case with a large deletion of 108 kb-long. Moreover, we showed that, in most cases, somatic mutations do not affect the whole plant; instead, they affect only one cell layer, leading to periclinal chimeras associating two genotypes. Analysis of bud sports of Pinot gris support the hypothesis that cell layer rearrangements in the chimera lead to the homogenization of the genotype in the whole plant. Our findings shed new light on the way molecular and cellular mechanisms shape the grapevine genotypes during vegetative propagation, and enable us to propose a scheme of evolutionary mechanism of the Pinot clones.

  11. Chromosome replacement and deletion lead to clonal polymorphism of berry color in grapevine.

    Science.gov (United States)

    Pelsy, Frédérique; Dumas, Vincent; Bévilacqua, Lucie; Hocquigny, Stéphanie; Merdinoglu, Didier

    2015-04-01

    Clonal polymorphism mainly results from somatic mutations that occur naturally during plant growth. In grapevine, arrays of clones have been selected within varieties as a valuable source of diversity, among them clones showing berry color polymorphism. To identify mutations responsible for this color polymorphism, we studied a collection of 33 clones of Pinot noir, Pinot gris, and Pinot blanc. Haplotypes of the L2 cell layer of nine clones were resolved by genotyping self-progenies with molecular markers along a 10.07 Mb region of chromosome 2, including the color locus. We demonstrated that at least six haplotypes could account for the loss of anthocyanin biosynthesis. Four of them resulted from the replacement of sections of the 'colored' haplotype, sized from 31 kb to 4.4 Mb, by the homologous sections of the 'white' haplotype mutated at the color locus. This transfer of information between the two homologous sequences resulted in the partial homozygosity of chromosome 2, associated in one case with a large deletion of 108 kb-long. Moreover, we showed that, in most cases, somatic mutations do not affect the whole plant; instead, they affect only one cell layer, leading to periclinal chimeras associating two genotypes. Analysis of bud sports of Pinot gris support the hypothesis that cell layer rearrangements in the chimera lead to the homogenization of the genotype in the whole plant. Our findings shed new light on the way molecular and cellular mechanisms shape the grapevine genotypes during vegetative propagation, and enable us to propose a scheme of evolutionary mechanism of the Pinot clones.

  12. 19-base pair deletion polymorphism of the dihydrofolate reductase (DHFR gene: maternal risk of Down syndrome and folate metabolism

    Directory of Open Access Journals (Sweden)

    Cristiani Cortez Mendes

    Full Text Available CONTEXT AND OBJECTIVE: Polymorphisms in genes involved in folate metabolism may modulate the maternal risk of Down syndrome (DS. This study evaluated the influence of a 19-base pair (bp deletion polymorphism in intron-1 of the dihydrofolate reductase (DHFR gene on the maternal risk of DS, and investigated the association between this polymorphism and variations in the concentrations of serum folate and plasma homocysteine (Hcy and plasma methylmalonic acid (MMA. DESIGN AND SETTING: Analytical cross-sectional study carried out at Faculdade de Medicina de São José do Rio Preto (Famerp. METHODS: 105 mothers of individuals with free trisomy of chromosome 21, and 184 control mothers were evaluated. Molecular analysis on the polymorphism was performed using the polymerase chain reaction (PCR through differences in the sizes of fragments. Folate was quantified by means of chemiluminescence, and Hcy and MMA by means of liquid chromatography and sequential mass spectrometry. RESULTS: There was no difference between the groups in relation to allele and genotype frequencies (P = 0.44; P = 0.69, respectively. The folate, Hcy and MMA concentrations did not differ significantly between the groups, in relation to genotypes (P > 0.05. CONCLUSIONS: The 19-bp deletion polymorphism of DHFR gene was not a maternal risk factor for DS and was not related to variations in the concentrations of serum folate and plasma Hcy and MMA in the study population.

  13. Screening the dystrophin gene suggests a high rate of polymorphism in general but no exonic deletions in schizophrenics

    Energy Technology Data Exchange (ETDEWEB)

    Lindor, N.M.; Sobell, J.L.; Thibodeau, S.N. [Mayo Clinic/Foundation, Rochester, MN (United States)] [and others

    1994-03-15

    The dystrophin gene, located at chromosome Xp21, was evaluated as a candidate gene in chronic schizophrenia in response to the report of a large family in which schizophrenia cosegregated with Becker muscular dystrophy. Genomic DNA from 94 men with chronic schizophrenia was evaluated by Southern blot analysis using cDNA probes that span exons 1-59. No exonic deletions were identified. An unexpectedly high rate of polymorphism was calculated in this study and two novel polymorphisms were found, demonstrating the usefulness of the candidate gene approach even when results of the original study are negative. 41 refs., 1 fig., 4 tabs.

  14. Angiotensin-converting enzyme gene insertion/deletion polymorphism in migraine patients

    Directory of Open Access Journals (Sweden)

    White Linda R

    2008-03-01

    Full Text Available Abstract Background The main objective of this study was to investigate the angiotensin converting enzyme (ACE genotype as a possible risk factor for migraine (both with and without aura compared to controls. We also wanted to examine whether a clinical response to an ACE inhibitor, lisinopril, or an angiotensin II receptor blocker, candesartan, in migraine prophylaxis was related to ACE genotype. Methods 347 migraine patients aged 18–68 (155 migraine without aura (MoA, 187 migraine with aura (MwA and 5 missing aura subgroup data and 403 healthy non-migrainous controls > 40 years of age were included in the study. A polymerase chain reaction (PCR was performed on the genomic DNA samples to obtain the ACE insertion (I/deletion(D polymorphisms. Results No significant differences between migraine patients and controls were found with regard to ACE genotype and allele distributions. Furthermore, there was no significant difference between the controls and the MwA or MoA subgroups. Conclusion In our sample there is no association between ACE genotype or allele frequency and migraine. In addition, ACE genotype in our experience did not predict the clinical response to lisinopril or candesartan used as migraine prophylactics.

  15. Restriction fragment length polymorphism caused by a deletion involving Alu sequences within the human. alpha. sub 2 -plasmin inhibitor gene

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Osamu; Sugahara, Yuichi; Nakamura, Yuichi; Hirosawa, Shinsaku; Aoki, Nobuo (Tokyo Medical and Dental Univ. (Japan))

    1989-06-13

    A restriction fragment length polymorphism within the human {alpha}{sub 2}-plasmin inhibitor gene has been detected by Southern blot hybridization using an {alpha}{sub 2}-plasmin inhibitor cDNA probe. This restriction fragment length polymorphism can be attributed to the presence of two alleles, A and B, that are distributed in Hardy-Weinberg equilibrium with frequencies of 73.5% and 2.65%, respectively, in 66 unrelated Caucasian individuals or with frequencies of 51.0% and 49.0%, respectively, in 50 unrelated Japanese individuals. The minor allele, B, is due to a deletion of about 720 base pairs in intron 8 of the {alpha}{sub 2}-plasmin inhibitor gene. Sequence analysis of the deletion junction in allele B and the corresponding regions of allele A demonstrated the presence of oppositely oriented Alu sequences at the 5{prime} and 3{prime} deletion boundaries. These data suggest that this restriction fragment length polymorphism was caused by intrastrand recombination between Alu sequences.

  16. The PML gene is linked to a megabase-scale insertion/deletion restriction fragment length polymorphism

    Energy Technology Data Exchange (ETDEWEB)

    Goy, A.; Xiao, Y.H.; Passalaris, T. [Memorial Sloan-Kettering Cancer Center, New York, NY (United States)] [and others

    1995-03-20

    The PML gene located on chromosome band 15q22 is involved with the RAR{alpha} locus (17q21) in a balanced reciprocal translocation uniquely observed in acute promyelocytic leukemia. Physical mapping studies by pulsed-field gel electrophoresis revealed that the PML gene is flanked by two CpG islands that are separated by a variable distance in normal individuals. Several lines of evidence demonstrate that this is the consequence of a large insertion/deletion polymorphism linked to the PML locus: (1) overlapping fragments obtained with a variety of rare-cutting restriction enzymes demonstrated the same variability in distance between the flanking CpG islands; (2) mapping with restriction enzymes insensitive to CpG methylation confirmed that the findings were not a consequence of variable methylation of CpG dinucleotides; (3) the polymorphism followed a Mendelian inheritance pattern. This polymorphism is localized 3{prime} to the PML locus. There are five common alleles, described on the basis of BssHII fragments, ranging from 220 to 350 kb with increments of approximately 30 kb between alleles. Both heterozygous (61%) and homozygous (391%) patterns were observed in normal individuals. Mega-base-scale insertion/deletion restriction fragment length polymorphisms are very rare and have been described initially in the context of multigene families. Such structures have been also reported as likely regions of genetic instability. High-resolution restriction mapping of this particular structure linked to the PML locus is underway. 47 refs., 4 figs., 1 tab.

  17. The HDAC inhibitor SB939 overcomes resistance to BCR-ABL kinase Inhibitors conferred by the BIM deletion polymorphism in chronic myeloid leukemia.

    Science.gov (United States)

    Rauzan, Muhammad; Chuah, Charles T H; Ko, Tun Kiat; Ong, S Tiong

    2017-01-01

    Chronic myeloid leukemia (CML) treatment has been improved by tyrosine kinase inhibitors (TKIs) such as imatinib mesylate (IM) but various factors can cause TKI resistance in patients with CML. One factor which contributes to TKI resistance is a germline intronic deletion polymorphism in the BCL2-like 11 (BIM) gene which impairs the expression of pro-apoptotic splice isoforms of BIM. SB939 (pracinostat) is a hydroxamic acid based HDAC inhibitor with favorable pharmacokinetic, physicochemical and pharmaceutical properties, and we investigated if this drug could overcome BIM deletion polymorphism-induced TKI resistance. We found that SB939 corrects BIM pre-mRNA splicing in CML cells with the BIM deletion polymorphism, and induces apoptotic cell death in CML cell lines and primary cells with the BIM deletion polymorphism. More importantly, SB939 both decreases the viability of CML cell lines and primary CML progenitors with the BIM deletion and restores TKI-sensitivity. Our results demonstrate that SB939 overcomes BIM deletion polymorphism-induced TKI resistance, and suggest that SB939 may be useful in treating CML patients with BIM deletion-associated TKI resistance.

  18. The HDAC inhibitor SB939 overcomes resistance to BCR-ABL kinase Inhibitors conferred by the BIM deletion polymorphism in chronic myeloid leukemia.

    Directory of Open Access Journals (Sweden)

    Muhammad Rauzan

    Full Text Available Chronic myeloid leukemia (CML treatment has been improved by tyrosine kinase inhibitors (TKIs such as imatinib mesylate (IM but various factors can cause TKI resistance in patients with CML. One factor which contributes to TKI resistance is a germline intronic deletion polymorphism in the BCL2-like 11 (BIM gene which impairs the expression of pro-apoptotic splice isoforms of BIM. SB939 (pracinostat is a hydroxamic acid based HDAC inhibitor with favorable pharmacokinetic, physicochemical and pharmaceutical properties, and we investigated if this drug could overcome BIM deletion polymorphism-induced TKI resistance. We found that SB939 corrects BIM pre-mRNA splicing in CML cells with the BIM deletion polymorphism, and induces apoptotic cell death in CML cell lines and primary cells with the BIM deletion polymorphism. More importantly, SB939 both decreases the viability of CML cell lines and primary CML progenitors with the BIM deletion and restores TKI-sensitivity. Our results demonstrate that SB939 overcomes BIM deletion polymorphism-induced TKI resistance, and suggest that SB939 may be useful in treating CML patients with BIM deletion-associated TKI resistance.

  19. A new insertion/deletion fragment polymorphism of inhibin-α gene associated with follicular cysts in Large White sows.

    Science.gov (United States)

    Li, Wanhong; Chen, Shuxiong; Li, Hongjiao; Liu, Zhuo; Zhao, Yun; Chen, Lu; Zhou, Xu; Li, Chunjing

    2016-05-18

    Ovarian follicular cysts are anovulatory follicular structures that lead to infertility. Hormones play key roles in the formation and persistence of cysts. Inhibins are heterodimeric gonadal glycoprotein hormones that belong to the transforming growth factor-β superfamily. These hormones suppress the secretion of follicle-stimulating hormone. In this report, partial fragment of inhibin-α (INHA) subunit gene of Large White pig was detected from the genomic DNA by polymerase chain reaction. The sequence showed a 283 bp fragment insertion/deletion (I/D) polymorphism in INHA subunit gene. A total of 49 Large White sows with cystic follicles and 152 normal sows were screened for this polymorphism. The relationship of INHA I/D polymorphisms with follicular cysts was investigated. The distribution of I/D was significantly different between cystic and normal sows, thereby suggesting that the INHA subunit gene might be a potential biological marker for breeding programs in pig.

  20. The ID genotype of MDM2 40 bp insertion/deletion polymorphism was associated with lower risk of SLE.

    Science.gov (United States)

    Salimi, Saeedeh; Rezaei, Mahnaz; Mohammadpour-Gharehbagh, Abbas; Sajadian, Mojtaba; Sandoughi, Mahnaz

    2017-07-04

    In patients with systemic lupus erythematosus (SLE), loss of immunological tolerance to self-nuclear antigens and abnormal activation of self-reactive T and B cells lead to self-antibodies and immune complex production. The autoreactive lymphocytes are removed by the apoptotic process in healthy individuals; however, apoptosis disruption could cause accumulation of apoptotic bodies and nuclear debris. Therefore, apoptosis plays a crucial role in the pathogenesis of autoimmune diseases. To investigate the association between two polymorphisms in an apoptotic-related gene, MDM2, and SLE. A case-control study was conducted on 200 patients with SLE and 206 healthy volunteers matched for age, sex, and ethnicity. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and PCR methods were used for genotyping. No association was found between the MDM2 T309G polymorphism (rs2279744) and SLE. The ID genotype of the insertion/deletion (I/D) polymorphism (rs3730485) was significantly lower in patients with SLE, and the ID genotype could be a protective factor for SLE. The DD genotype was not associated with SLE. The frequency of combined TT/ID and GG/ID genotypes of MDM2 T309G and I/D polymorphisms was lower in the patients with SLE and was associated with a lower risk of SLE. The frequency of the TD haplotype of MDM2 T309G and I/D polymorphisms was significantly lower in patients with SLE and could reduce the SLE risk. The ID genotype of the MDM2 I/D polymorphism was associated with a lower risk of SLE. There was no association between MDM2 T309G polymorphism and SLE. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  1. Angiotensin-converting enzyme (ACE) gene insertion/deletion polymorphism is not a risk factor for hypertension in SLE nephritis.

    Science.gov (United States)

    Negi, Vir S; Devaraju, Panneer; Gulati, Reena

    2015-09-01

    SLE is a systemic autoimmune disease with high prevalence of hypertension. Around 40-75 % of SLE patients develop nephritis, a major cause of hypertension and mortality. Angiotensin-converting enzyme (ACE) maintains the blood pressure and blood volume homeostasis. An insertion/deletion (I/D) polymorphism in intron 16 of ACE gene was reported to influence the development of hypertension, nephritis, and cardiovascular diseases in different ethnic populations. Despite compelling evidence for the high prevalence of hypertension in individuals with SLE, underlying factors for its development are not well studied. With this background, we analyzed the influence of ACE insertion/deletion polymorphism on susceptibility to SLE, development of nephritis and hypertension, other clinical features and autoantibody phenotype in South Indian SLE patients. Three hundred patients with SLE and 460 age and sex similar ethnicity matched individuals were included as patients and healthy controls, respectively. The ACE gene insertion/deletion polymorphism was analyzed by PCR. Insertion (I) and deletion (D) alleles were observed to be equally distributed among patients (57 and 43 %) and controls (59 and 41 %), respectively. The mutant (D) allele did not confer significant risk for SLE (II vs. ID: p = 0.4, OR 1.15, 95 % CI 0.8-1.6; II vs. DD: p = 0.34, OR 1.22, 95 % CI 0.8-1.85). There was no association of the ACE genotype or the allele with development of lupus nephritis (II vs. ID: p = 0.19, OR 1.41, 95 % CI 0.84-2.36; II vs. DD: p = 0.41, OR 0.74, 95 % CI 0.38-1.41) or hypertension (II vs. ID: p = 0.85, OR 0.9, 95 % CI 0.43-1.8; II vs. DD: p = 0.66, OR 1.217, 95 % CI 0.5-2.8). The presence of mutant allele (D) was not found to influence any clinical features or autoantibody phenotype. The insertion/deletion polymorphism of the ACE gene is not a genetic risk factor for SLE and does not influence development of hypertension or lupus nephritis in South Indian

  2. High frequency electromagnetic dosimetry

    CERN Document Server

    Sánchez-Hernández, David A

    2009-01-01

    Along with the growth of RF and microwave technology applications, there is a mounting concern about the possible adverse effects over human health from electromagnetic radiation. Addressing this issue and putting it into perspective, this groundbreaking resource provides critical details on the latest advances in high frequency electromagnetic dosimetry.

  3. High association of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism with recurrent aphthous stomatitis.

    Science.gov (United States)

    Karakus, Nevin; Yigit, Serbulent; Kalkan, Goknur; Sezer, Saime

    2013-08-01

    Recurrent aphthous stomatitis (RAS) is a common ulcerative disease of the oral mucosa. Oral ulcers are also the most common feature of Behçet's disease (BD). Association of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism with BD has been reported in Turkish population. The aim of the present study was to investigate the possible association between ACE gene I/D polymorphism and RAS, and evaluate if there was an association with clinical features in a relatively large cohort of Turkish patients. The study included 198 patients affected by RAS and 214 healthy controls. ACE gene I/D polymorphism genotypes were determined using polymerase chain reaction with I and D allele-specific primers. The genotype and allele frequencies of I/D polymorphism showed statistically significant differences between RAS patients and controls (p < 0.0001 and p < 0.0001, respectively). After stratifying RAS patients according to clinical and demographical characteristics, no significant association was observed. In conclusion, the results of this study suggest that I/D polymorphism of the ACE gene was positively associated with predisposition to develop RAS in Turkish population. Further studies with larger populations are recommended.

  4. Alu insertion/deletion of ACE gene polymorphism might not affect ...

    African Journals Online (AJOL)

    Widodo

    2016-09-03

    Sep 3, 2016 ... D polymorphism of ACE on the enzyme's ability to catalyse bradykinin is still not widely known. Aims: This study aimed to examine the serum bradykinin level in hypertensive patients with I/D polymorphism of ACE, who were treated with ACE inhibitor. Subjects and methods: The serum bradykinin and I/D ...

  5. A 660-Kb Deletion with Antagonistic Effects on Fertility and Milk Production Segregates at High Frequency in Nordic Red Cattle: Additional Evidence for the Common Occurrence of Balancing Selection in Livestock

    Science.gov (United States)

    Kadri, Naveen Kumar; Sahana, Goutam; Charlier, Carole; Iso-Touru, Terhi; Guldbrandtsen, Bernt; Karim, Latifa; Nielsen, Ulrik Sander; Panitz, Frank; Aamand, Gert Pedersen; Schulman, Nina; Georges, Michel; Vilkki, Johanna; Lund, Mogens Sandø; Druet, Tom

    2014-01-01

    In dairy cattle, the widespread use of artificial insemination has resulted in increased selection intensity, which has led to spectacular increase in productivity. However, cow fertility has concomitantly severely declined. It is generally assumed that this reduction is primarily due to the negative energy balance of high-producing cows at the peak of lactation. We herein describe the fine-mapping of a major fertility QTL in Nordic Red cattle, and identify a 660-kb deletion encompassing four genes as the causative variant. We show that the deletion is a recessive embryonically lethal mutation. This probably results from the loss of RNASEH2B, which is known to cause embryonic death in mice. Despite its dramatic effect on fertility, 13%, 23% and 32% of the animals carry the deletion in Danish, Swedish and Finnish Red Cattle, respectively. To explain this, we searched for favorable effects on other traits and found that the deletion has strong positive effects on milk yield. This study demonstrates that embryonic lethal mutations account for a non-negligible fraction of the decline in fertility of domestic cattle, and that associated positive effects on milk yield may account for part of the negative genetic correlation. Our study adds to the evidence that structural variants contribute to animal phenotypic variation, and that balancing selection might be more common in livestock species than previously appreciated. PMID:24391517

  6. A 660-Kb deletion with antagonistic effects on fertility and milk production segregates at high frequency in Nordic Red cattle: additional evidence for the common occurrence of balancing selection in livestock.

    Directory of Open Access Journals (Sweden)

    Naveen Kumar Kadri

    2014-01-01

    Full Text Available In dairy cattle, the widespread use of artificial insemination has resulted in increased selection intensity, which has led to spectacular increase in productivity. However, cow fertility has concomitantly severely declined. It is generally assumed that this reduction is primarily due to the negative energy balance of high-producing cows at the peak of lactation. We herein describe the fine-mapping of a major fertility QTL in Nordic Red cattle, and identify a 660-kb deletion encompassing four genes as the causative variant. We show that the deletion is a recessive embryonically lethal mutation. This probably results from the loss of RNASEH2B, which is known to cause embryonic death in mice. Despite its dramatic effect on fertility, 13%, 23% and 32% of the animals carry the deletion in Danish, Swedish and Finnish Red Cattle, respectively. To explain this, we searched for favorable effects on other traits and found that the deletion has strong positive effects on milk yield. This study demonstrates that embryonic lethal mutations account for a non-negligible fraction of the decline in fertility of domestic cattle, and that associated positive effects on milk yield may account for part of the negative genetic correlation. Our study adds to the evidence that structural variants contribute to animal phenotypic variation, and that balancing selection might be more common in livestock species than previously appreciated.

  7. Association between DBH 19bp insertion/deletion polymorphism and cognition in schizophrenia with and without tardive dyskinesia.

    Science.gov (United States)

    Hui, Li; Han, Mei; Yin, Guang Zhong; Zhang, Yingyang; Huang, Xu Feng; Qian, Zheng Kang; Gu, Wei Guo; Gu, Xiao Chu; Zhu, Xiao Min; Soares, Jair C; Ning, Yuping; Zheng, Yingjun; Du, Xiang Dong; Zhang, Xiang Yang

    2017-04-01

    Long-term antipsychotic treatment for schizophrenia is associated with the development of tardive dyskinesia (TD), which is involved in increased cognitive impairment. Dopamine beta-hydroxylase (DBH) gene associated with dopamine and norepinephrine systems influences cognition. Schizophrenia with TD have higher DBH activity than those without TD. This study examined whether DBH5'-insertion/deletion (-Ins/Del) polymorphism could influence cognitive function in schizophrenia with and without TD. The presence of DBH5'-Ins/Del polymorphism was determined in 345 schizophrenia with TD and 397 schizophrenia without TD. The Abnormal Involuntary Movement Scale and Repeatable Battery for Assessment of Neuropsychological Status (RBANS) were used to assess TD severity and cognition. The allele and genotype frequencies of DBH5'-Ins/Del polymorphism did not differ between patients with and without TD (both p>0.05). RBANS total score and subscales did not differ by DBH5'-Ins/Del genotype groups in patients with TD (all p>0.05). However, attention score significantly differed by DBH5'-Ins/Del genotype groups in those without TD (pschizophrenia with TD, but it may influence cognitive function in schizophrenia with non-TD. Moreover, schizophrenia with TD experienced greater cognitive deficits than those with non-TD, especially in immediate memory and attention. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Association of the UCP2 45-bp insertion/deletion polymorphism with ...

    African Journals Online (AJOL)

    Uncoupling protein-2 (UCP2) regulates insulin secretion and may play an important role in linking obesity to diabetes type 2 (T2D) that represents a major public health problem in Saudi Arabia. The present study aimed to evaluate the association between the 45-bp insertion/deletion (ins/del) in 3'UTR exon 8 within the ...

  9. ACE Insertion/Deletion Polymorphism and Diabetic Nephropathy: Clinical Implications of Genetic Information

    Science.gov (United States)

    Ha, Sung-Kyu

    2014-01-01

    Approximately 20–40% of diabetic patients develop nephropathy which is the leading cause of ESRD in developed countries. The ACE I/D polymorphism is thought to be a marker for functional polymorphism which regulates circulating and tissue ACE activity. While the initial study found a protective effect of the II genotype on the development of nephropathy in IDDM patients, subsequent studies have addressed the role of ACE I/D polymorphism in the development and progression of diabetic nephropathy. RAAS blockers are the first line drugs for the treatment hypertension associated with diabetes and have been widely used in everyday clinical practice for the purpose of reducing proteinuria in patients with various renal diseases. However, the antiproteinuric effect of RAAS blockers is variable and the percentage of reducing proteinuria is in the range of 20–80%. The antiproteinuric effect of RAAS blockers may be related to a number of factors: the type or the dose of RAAS blockers, the duration of therapy, the level of sodium intake, and the type of patient's ACE I/D genotype. Besides the nongenetic factors, drug responses, can be influenced by ACE gene polymorphism. In this review, we discuss the relationship between ACE I/D polymorphism and diabetic nephropathy and therapeutic response of RAAS blockers. PMID:25587546

  10. A 660-Kb deletion with antagonistic effects on fertility and milk production segregates at high frequency in Nordic Red cattle: additional evidence for the common occurrence of balancing selection in livestock.

    OpenAIRE

    Naveen Kumar Kadri; Goutam Sahana; Carole Charlier; Terhi Iso-Touru; Bernt Guldbrandtsen; Latifa Karim; Ulrik Sander Nielsen; Frank Panitz; Gert Pedersen Aamand; Nina Schulman; Michel Georges; Johanna Vilkki; Mogens Sandø Lund; Tom Druet

    2014-01-01

    In dairy cattle, the widespread use of artificial insemination has resulted in increased selection intensity, which has led to spectacular increase in productivity. However, cow fertility has concomitantly severely declined. It is generally assumed that this reduction is primarily due to the negative energy balance of high-producing cows at the peak of lactation. We herein describe the fine-mapping of a major fertility QTL in Nordic Red cattle, and identify a 660-kb deletion encompassing four...

  11. Angiotensin-Converting Enzyme Gene Insertion/Deletion Polymorphism and Small Vessel Cerebral Stroke in Indian Population

    Directory of Open Access Journals (Sweden)

    Puttachandra Prabhakar

    2014-01-01

    Full Text Available Background. Hypertension is an established risk factor for small-vessel cerebral stroke and the renin-angiotensin system plays an important role in the maintenance of blood pressure. We aimed at evaluating the contribution of the angiotensin-converting enzyme (ACE gene insertion/deletion (I/D polymorphism to the risk of small-vessel stroke in south Indian population. Materials and Methods. We investigated 128 patients diagnosed with small-vessel stroke and 236 age, and gender-matched healthy controls. ACE I/D polymorphism was detected by polymerase chain reaction. Results. Hypertension was significantly more prevalent in the patient group and was associated with 6-fold increase in risk for stroke. ACE genotypes were in Hardy-Weinberg equilibrium in both patients and controls. Prevalence of DD, ID, and II genotypes in cases (34.4%, 43.7%, and 28% did not differ significantly from controls (31.8%, 43.2%, and 25%. The polymorphism was not associated with small-vessel stroke (OR: 1.34; 95% CI: 0.52–1.55. However, diastolic blood pressure was associated with the ACE I/D genotypes in the patients. (DD; 90.2±14.2> ID; 86.2±11.9> II; 82.3±7.8 mm Hg,  P=0.047. Conclusion. Our study showed that hypertension, but not ACE I/D polymorphism, increased the risk of small-vessel stroke.

  12. Distribution of Human Leukocyte Antigen alleles in Systemic Lupus Erythematosus patients with Angiotensin Converting Enzyme Insertion/Deletion Polymorphism

    Directory of Open Access Journals (Sweden)

    Nageen Hussain

    2013-02-01

    Full Text Available Systemic Lupus Erythematosus is one of the classic examples of autoimmune diseases among human beings and is a rare disease in Pakistani population. Clinically it is a quite diverse and complicated autoimmune disease in a sense that it involves multiple organs of the body and mimics with other diseases as well. This study focused on the distribution of HLA alleles in SLE patients with ACE I/D Polymorphism. A total of 122 individuals were enrolled in this study, 61 were the SLE patients who fulfilled revised ACR criteria and 61 were the healthy controls. Mean age of SLE patients at diagnosis was 30.35 ± 1.687 years (12-68 years. ACE gene I/D polymorphism was performed by nested PCR and DNA based HLA typing technique was used. ACE gene I/D polymorphism of Intron16 was studied and found to be involved in the activity of SLE. There is high frequency of HLA-A*01, HLA-B*40, HLA-DRB1*01 alleles in SLE patients with ACE DD genotype. The distribution of HLA-A, -B, -DRB1 alleles was analyzed in SLE patients with various disease phenotypes. HLA-A*01 and HLA-B*40 was the most common allele found in SLE patients with the involvement of skin. HLA-A*01, -A*03, HLA-B*13 and -B*46 were common in SLE patients with arthritis while HLA-A*26 and -A*69 were commonly found in Lupus nephritis cases. SLE patients involving both skin and kidney had an allele HLA-DRB1*01 common in them.

  13. Lack of association between intact/deletion polymorphisms of the APOBEC3B gene and HIV-1 risk.

    Directory of Open Access Journals (Sweden)

    Mayumi Imahashi

    Full Text Available The human APOBEC3 family of proteins potently restricts HIV-1 replication APOBEC3B, one of the family genes, is frequently deleted in human populations. Two previous studies reached inconsistent conclusions regarding the effects of APOBEC3B loss on HIV-1 acquisition and pathogenesis. Therefore, it was necessary to verify the effects of APOBEC3B on HIV-1 infection in vivo.Intact (I and deletion (D polymorphisms of APOBEC3B were analyzed using PCR. The syphilis, HBV and HCV infection rates, as well as CD4(+ T cell counts and viral loads were compared among three APOBEC3B genotype groups (I/I, D/I, and D/D. HIV-1 replication kinetics was assayed in vitro using primary cells derived from PBMCs.A total of 248 HIV-1-infected Japanese men who have sex with men (MSM patients and 207 uninfected Japanese MSM were enrolled in this study. The genotype analysis revealed no significant differences between the APOBEC3B genotype ratios of the infected and the uninfected cohorts (p = 0.66. In addition, HIV-1 disease progression parameters were not associated with the APOBEC3B genotype. Furthermore, the PBMCs from D/D and I/I subjects exhibited comparable HIV-1 susceptibility.Our analysis of a population-based matched cohort suggests that the antiviral mechanism of APOBEC3B plays only a negligible role in eliminating HIV-1 in vivo.

  14. Lack of relationship between an insertion/deletion polymorphism in the angiotensin I-converting enzyme gene and diabetic nephropathy and proliferative retinopathy in IDDM patients

    DEFF Research Database (Denmark)

    Tarnow, L; Cambien, Francois; Rossing, P

    1995-01-01

    Genotypic abnormalities of the renin-angiotensin system have been suggested as a risk factor for the development of diabetic nephropathy and proliferative retinopathy. We studied the relationship between an insertion(I)/deletion (D) polymorphism in the angiotensin-converting enzyme (ACE) gene in ...

  15. Cost-effectiveness of ACE inhibitor therapy to prevent dialysis in nondiabetic nephropathy : Influence of the ACE insertion/deletion polymorphism

    NARCIS (Netherlands)

    Vegter, Stefan; Perna, A.; Hiddema, W.; Ruggenenti, P.; Remuzzi, G.; Navis, Ger Jan; Postma, Maarten

    Introduction End-stage renal disease is associated with high health-care costs and low quality of life compared with chronic kidney disease. The renoprotective effectiveness of angiotensin-converting enzyme inhibitors (ACEi) is largely determined by the ACE insertion/deletion (I/D) polymorphism. We

  16. Traditional risk factors and angiotensin-converting enzyme insertion/deletion gene polymorphism in coronary artery disease.

    Science.gov (United States)

    Sahin, S; Ceyhan, K; Benli, I; Ozyurt, H; Naseri, E; Tumuklu, M M; Aydogan, L; Elalmis, A O; Ozugurlu, A F; Onalan, O

    2015-03-20

    We investigated whether the insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme (ACE) gene and serum ACE levels are associated with traditional risk factors of coronary artery disease (CAD). We enrolled 250 individuals without CAD and 750 individuals suffering from CAD who were angiographically diagnosed. Biochemical risk factors, the ACE (I/D) gene polymorphism, and ACE serum levels were compared. ACE genotypes were determined using real-time polymerase chain reaction. ACE serum levels were determined using an enzyme-linked immunosorbent assay. Lipid parameters were determined spectrophotometrically using an autoanalyzer. Compared to the control group, the CAD group showed significantly higher serum ACE levels (P < 0.001). The highest ACE levels were found in those with the DD genotype. Other genotypes also presented statistically significant differences. We observed a significant difference between the control and coronary patient groups regarding the levels of total cholesterol, triglyceride, high-density lipoprotein-cholesterol, and low-density lipoprotein-cholesterol (P < 0.05). ACE (I/D) genotypes and serum ACE levels may be associated with risk factors and the development of CAD.

  17. Plasmodium vivax merozoite surface protein PvMSP-3 beta is radically polymorphic through mutation and large insertions and deletions.

    Science.gov (United States)

    Rayner, Julian C; Huber, Curtis S; Feldman, Dmitry; Ingravallo, Paul; Galinski, Mary R; Barnwell, John W

    2004-12-01

    Plasmodium vivax causes the majority of malaria outside of sub-Saharan Africa and is an important burden for affected countries. The recent spread of drug-resistant P. vivax strains in these countries has led to renewed pressure for the development of a P. vivax vaccine. The complex life cycle of P. vivax presents many potential vaccine targets, but among the most promising candidates are subunits of the surface coat that surrounds the merozoite, the parasite stage that infects erythrocytes and initiates much of the pathology of malaria. Although the genes for several constituents of the P. vivax surface coat have now been cloned and sequenced, little is known about the extent to which these proteins vary between populations, an important consideration in vaccine development. The merozoite surface protein MSP-3beta is a member of a family of related merozoite surface proteins, all of which contain a central alanine-rich domain that is predicted to form a coiled-coil tertiary structure. We have sequenced the PvMSP-3 beta gene from P. vivax isolates originating in Central and South America, Asia and the Pacific. In this first assessment of PvMSP-3 beta variation between populations, we discovered widespread and significant diversity, mostly within the alanine-rich central region. We observed frequent differences in PvMSP-3 beta gene size, caused by the insertion and/or deletion of several large sequence blocks, as well as numerous single nucleotide polymorphisms and smaller scale insertions and deletions. Despite this high level of sequence diversity, certain physical properties of the encoded protein are maintained, particularly the ability to form coiled-coil tertiary structures, suggesting that although PvMSP-3 beta varies widely, it is under functional constraints. The implications for PvMSP-3 beta function and vaccine development are discussed.

  18. [Angiotensin-converting enyme insertion/deletion polymorphism and blood pressure regulation in type 2 diabetic patients].

    Science.gov (United States)

    Krajina-Andricević, Mirna; Zibar, Lada; Glavas-Obrovac-, Ljubica; Stefanić, Mario; Avdicević, Monika; Barbić, Jerko

    2011-10-01

    The renin-angiotensin system (RAS) has been shown to have important role in blood pressure regulation. Inconsistent results have been reported regarding the association of the angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism (NCBI ref. SNP ID: rs1799752) and hypertension as well as a contributing factor in the development of diabetic nephropathy. Aim of the study was to investigate the significance of insertion/deletion polymorphism of angiotensin-converting enzyme as contributing factor to blood pressure regulation in type 2 diabetic patients with diabetic nephropathy and those with preserved renal function. Genomic DNA was extracted from whole blood of 100 patients with diabetic nephropathy and 102 diabetic patients with normal renal function (urinary protein excretion rate less than 300 mg/day and creatinin clearence level > or = 80 ml/min). Blood pressure measurement was done 3 times by a nurse in the supine position, in 15 minutes intervals. Mean arterial pressure (MAP) was calculated according to the standard equation- (systolic pressure + 2 x diastolic pressure)/3, for all measurements. Genotyping was carried out using primers and fluorescent probes in a Lyght Cycler System. Statistical analysis was performed using software package SPSS 16.0 (SPSS inc, Chicago, IL, USA). Genotype frequencies of the ACE I/D) polymorphysm were in accordance with the Hardy-Weinberg equilibrium. In all subjects, the frequencies of the DD. ID and II genotypes were 0.32; 0.45 and 0.23 respectively. The allelic frequency of the D allele in nephropatby group was 0.82 and 0.72 in the control group. The highest systolic blood pressure was in the subjects with DD genotype. Systolic and mean, arterial pressure were significantly higher in diabetic nephropathy patients compared to patients with preserved kidney function, only if D allele was present (systolic blood pressure: DD t=2,877, p=0,006; ID t=2.733, p=0,008; mean arterial pressure: DD t=2,687, p=0.009; ID

  19. Population genetics of 30 insertion/deletion polymorphisms in Han Chinese population from Zhejiang Province.

    Science.gov (United States)

    Liu, Xiling; Chen, Fang; Niu, Yong; Bian, Yingnan; Zhang, Suhua; Zhu, Ruxin; Li, Chengtao

    2017-05-01

    Insertion/deletion (InDels) markers can serve as a useful supporting tool to short tandem repeat (STR) typing systems for human identification. The Qiagen DIPplex Investigator kit, which contains 30 biallelic autosomal InDels and amelogenin, has been developed for forensic use. To estimate the genetic diversity of the 30 markers in Han Chinese individuals living in Zhejiang and to further evaluate their applicability in forensic science, 246 unrelated Han Chinese from Zhejiang were genotyped at these loci. No significant departures from Hardy-Weinberg equilibrium were observed at these loci in these participants. The combined power of discrimination was over 0.99999999 and the combined probability of exclusion was over 0.9901. Results demonstrated that the 30 InDel markers could be used as a supporting tool for the human identification of specific Han Chinese individuals from Zhejiang. The genetic differences and phylogenetic relationships among Han Chinese from Zhejiang, Han Chinese from five other areas, nine minority ethnic groups, as well as two other East Asian populations were also investigated. Two InDel markers, HLD39 and HLD40, showed significant allele-frequency differences between Han Chinese from Zhejiang and ethnic minorities. Further analysis can be used to evaluate their role in forensic science. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. The ACE Gene Insertion/Deletion Polymorphism and Cerebrovascular Diseases in Uzbek Patients with Arterial Hypertension

    Directory of Open Access Journals (Sweden)

    Nargiza U. Makhkamova

    2016-09-01

    Full Text Available The aim of the present study was to investigate the association between the ACE gene I/D polymorphism and the development of hypertensive encephalopathy (HE in Uzbek patients with hypertension (HT. Materials and methods: The study included 91 male patients aged from 32 to 74 years (mean age 52.5±9.2 with HT Grade 1, 2 and 3 (ESH/ESC, 2013 [4] and presence of HE. All patients were checked on office BP using Korotkov’s method and ambulatory blood pressure monitoring (ABPM. Intima-media thickness (IMT of the carotid artery was measured by a 7.5MHz high-resolution ultrasound. Genomic DNA was isolated from peripheral blood using the DiatomTM DNA Prep 200 Kit according to the manufacturer's protocol. ACE gene I/D polymorphism genotypes were determined by PCR. Results: Among HT patients with HE, we have identified a statistically significant predominance of ID genotype carriers (65.9% against carriers of the II genotype (18.75 and DD genotype (15.4% (P=0.000; the frequency of I and D alleles was 51.6% and 48.4%, respectively (P>0.05. Comparative analysis showed a possible association between the ID genotype/D allele and HE development in HT patients, according to the general model (OR = 6.36; 95% CI 3.04 -13.31; p=0.000 and multiplicative model (OR = 2.02; 95% CI 1.25 -3.27; p=0.004 of inheritance. High grades of HT were predominant in carriers of the DD genotype. IMT was significantly higher in carriers of the DD genotype than in carriers of the II and ID genotypes. The carriage of D allele was associated with the highest levels of TC, TG, and VLDL-C. Carriers of the DD genotype were characterized by higher values of daytime SBP, nighttime SBP variability and nighttime SBP load.

  1. Impact of the growth hormone receptor exon 3 deletion gene polymorphism on glucose metabolism, lipids, and insulin-like growth factor-I levels during puberty

    DEFF Research Database (Denmark)

    Sørensen, Kaspar; Aksglaede, Lise; Munch-Andersen, Thor

    2009-01-01

    CONTEXT: The GH/IGF-I axis has major impact on insulin sensitivity and insulin secretion. Recently a polymorphism in the GH receptor gene (GHR), a genomic deletion of exon 3 (GHRd3), has been linked to increased responsiveness to GH. OBJECTIVE: The objective of the present study was to evaluate...... the impact of the GHRd3 gene polymorphism on insulin sensitivity, insulin secretion, lipids, and IGF-I levels in healthy children and adolescents. DESIGN: This was cross-sectional and was part of the COPENHAGEN puberty study. SETTING: The study was conducted at a tertiary center for pediatric endocrinology...

  2. EGFR exon 19 in-frame deletion and polymorphisms of DNA repair genes in never-smoking female lung adenocarcinoma patients.

    Science.gov (United States)

    Yang, Shi-Yi; Yang, Tsung-Ying; Li, Yao-Jen; Chen, Kun-Chieh; Liao, Kuo-Meng; Hsu, Kuo-Hsuan; Tsai, Chi-Ren; Chen, Chih-Yi; Hsu, Chung-Ping; Hsia, Jiun-Yi; Chuang, Cheng-Yen; Tsai, Ying-Huang; Chen, Kuan-Yu; Huang, Ming-Shyan; Su, Wu-Chou; Chen, Yuh-Min; Hsiung, Chao A; Shen, Chen-Yang; Chang, Gee-Chen; Yang, Pan-Chyr; Chen, Chien-Jen

    2013-01-15

    We explored potential associations between genetic polymorphisms in genes related to DNA repair and detoxification metabolism and epidermal growth factor receptor (EGFR) mutations in a cohort of 410 never-smoking patients with lung adenocarcinoma. Multivariate-adjusted odds ratios (aORs) and corresponding 95% confidence intervals (CI) of EGFR mutation status in association with the genotypes of DNA repair and detoxification metabolism genes were evaluated using logistic regression analysis. We found an association between in-frame deletion in EGFR exon 19 and a single nucleotide polymorphism (SNP) rs1800566C/T located in NQO1 (aOR, 2.2 with 95% CI, 1.0-4.8) in female never-smokers. The SNP rs744154C/G in ERCC4 was also associated with the EGFR exon 19 in-frame deletion both in never-smokers (aOR, 1.7 with 95% CI, 1.0-3.0) and female never-smokers (aOR, 1.9 with 95% CI, 1.0-3.6). Although the association was marginally significant in multivariate logistic regression analysis, the A/A genotype of rs1047840 in EXO1 was associated with a 7.6-fold increase in the occurrence of the EGFR exon 19 in-frame deletion in female never-smokers. Moreover, risk alleles in NQO1, ERCC4 and EXO1 were associated with an increasing aOR of the EGFR exon 19 in-frame deletion both in never-smokers (p = 0.007 for trend) and female never-smokers (p = 0.002 for trend). Our findings suggest that the in-frame deletion in EGFR exon 19 is associated with polymorphisms in DNA repair and detoxification metabolism genes in never-smoking lung adenocarcinoma patients, especially in females. Copyright © 2012 UICC.

  3. Distribution of Angiotensin-1 Converting Enzyme Insertion/Deletion and α-Actinin-3 Codon 577 Polymorphisms in Turkish Male Soccer Players

    Directory of Open Access Journals (Sweden)

    Korkut Ulucan

    2015-01-01

    Full Text Available Angiotensin-1 converting enzyme (ACE gene and α-actinin-3 (ACTN3 gene polymorphisms are considered to be the most important candidate genes for genetic predisposition to human athletic performance. In the present study, we aimed to analyze the distribution of ACE and ACTN3 polymorphisms for the first time in male Turkish soccer players. In this prospective study, our cohort consisted of 25 professional players, all with Turkish ancestry. Polymerase chain reaction (PCR-restriction length polymorphism was used for the characterization of the genotype of ACTN3 and single PCR for ACE . For ACE genotype, 16%, 44%, and 40% of the players had insertion/insertion (II, insertion/deletion (ID, and deletion/deletion (DD genotypes, respectively, whereas 20% had XX, 36% had RX, and 44% had RR genotypes for ACTN3 . When we examined the allelic percentages, for ACE , D allele was recorded as 62 and I as 38, and for ACTN3 , R allele was 62 and X was 38. Our results were in agreement with the previous reports, indicating the presence of ACTN3 D and ACE X allele in soccer players. We suggest that ACE and ACTN3 genotypes are important biomarkers for genetic counseling for the individuals who are prone to be successful soccer players.

  4. Geographies of High Frequency Trading

    DEFF Research Database (Denmark)

    Grindsted, Thomas Skou

    2016-01-01

    This paper investigates the geographies of high frequency trading. Today shares shift hands within micro seconds, giving rise to a form of financial geographies termed algorithmic capitalism. This notion refers to the different spatio-temporalities produced by high frequency trading, under...... the valuation of time. As high frequency trading accelerates financial markets, the paper examines the spatio-temporalities of automated trading by the ways in which the speed of knowledge exploitation in financial markets is not only of interest, but also the expansion between different temporalities....... The paper demonstrates how the intensification of time-space compression produces radical new dynamics in the financial market and develops information rent in HFT as convertible to a time rent and a spatio-temporal rent. The final section discusses whether high frequency trading only responds to crises...

  5. Effect of ACE insertion/deletion and 12 other polymorphisms on clinical outcomes and response to treatment in the life study

    DEFF Research Database (Denmark)

    Nordestgaard, Børge G; Kontula, Kimmo; Benn, Marianne

    2010-01-01

    OBJECTIVE: This pharmacogenetics substudy from the Losartan Intervention for Endpoint reduction in Hypertension study in patients with hypertension and left ventricular hypertrophy (LVH) treated with the angiotensin receptor blocker losartan versus the beta-blocker atenolol for 4.8 years tested...... whether the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene and 12 other previously well-characterized polymorphisms of hypertension susceptibility genes affected blood pressure reduction, heart rate reduction, cardiovascular events, and/or response to treatment....... These polymorphisms were chosen because they could affect blood pressure control or the pharmacological action of losartan or atenolol. METHODS: We genotyped 3503 patients, 1774 on losartan and 1729 on atenolol. RESULTS: ACE and the 12 other genotypes did not affect the reduction in systolic blood pressure, diastolic...

  6. The insertion and deletion (I28005D) polymorphism of the angiotensin I converting enzyme gene is a risk factor for osteoarthritis in an Asian Indian population.

    Science.gov (United States)

    Poornima, Subhadra; Subramanyam, Krishna; Khan, Imran Ali; Hasan, Qurratulain

    2015-12-01

    Angiotensin I converting enzyme (ACE) insertion and deletion (I/D) polymorphism has been implicated in the pathogenesis of osteoarthritis (OA). In recent years, numerous genetic factors have been identified and implicated in OA. In this Asian Indian population-based study, we aimed to evaluate the relationship between ACE (I28005D) gene polymorphism and primary OA. We performed a case-control association study to identify and explore the correlation between clinically, radiologically diagnosed individuals with primary knee OA and the ACE I/D polymorphism. Genomic DNA was isolated from 200 samples, including 100 OA cases and 100 healthy volunteers. DNA was amplified by polymerase chain reaction (PCR) using I and D allele-specific primers. PCR products were assessed via UV visualization of products electrophoresed on 2% agarose gels. The groups differed significantly in genotype distributions (p risk factor for early onset primary knee OA. © The Author(s) 2014.

  7. Association between insertion/deletion polymorphism in angiotensin-converting enzyme gene and acute lung injury/acute respiratory distress syndrome: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Matsuda Akihisa

    2012-08-01

    Full Text Available Abstract Background A previous meta-analysis reported a positive association between an insertion/deletion (I/D polymorphism in the angiotensin-converting enzyme gene (ACE and the risk of acute lung injury (ALI/acute respiratory distress syndrome (ARDS. Here, we updated this meta-analysis and additionally assessed the association of this polymorphism with ALI/ARDS mortality. Methods We searched electronic databases through October 2011 for the terms “angiotensin-converting enzyme gene”, “acute lung injury”, and “acute respiratory distress syndrome,” and reviewed all studies that reported the relationship of the I/D polymorphism in ACE with ALI/ARDS in humans. Seven studies met the inclusion criteria, comprising 532 ALI/ARDS patients, 3032 healthy controls, and 1432 patients without ALI/ARDS. We used three genetic models: the allele, dominant, and recessive models. Results The ACE I/D polymorphism was not associated with susceptibility to ALI/ARDS for any genetic model. However, the ACE I/D polymorphism was associated with the mortality risk of ALI/ARDS in Asian subjects ( Pallele Pdominant = 0.001, Precessive = 0.002. This finding remained significant after correction for multiple comparisons. Conclusions There is a possible association between the ACE I/D polymorphism genotype and the mortality risk of ALI/ARDS in Asians.

  8. High-frequency Trader Subjectivity

    DEFF Research Database (Denmark)

    Borch, Christian; Lange, Ann-Christina

    2017-01-01

    In this article, we examine the recent shift in financial markets toward high-frequency trading (HFT). This turn is being legitimized with reference to how algorithms are allegedly more rational and efficient than human traders, and less prone to emotionally motivated decisions. We argue......-techniques of the ideal high-frequency trader. We demonstrate that these traders face the challenge of avoiding emotional interference in their algorithms and that they deploy a set of disciplinary self-techniques to curb the importance of emotional attachment....

  9. Potentially harmful advantage to athletes: a putative connection between UGT2B17 gene deletion polymorphism and renal disorders with prolonged use of anabolic androgenic steroids

    Directory of Open Access Journals (Sweden)

    Barker James

    2010-04-01

    Full Text Available Abstract Background and objective With prolonged use of anabolic androgenic steroids (AAS, occasional incidents of renal disorders have been observed. Independently, it has also been established that there are considerable inter-individual and inter-ethnic differences, in particular with reference to the uridine diphosphate-glucuronosyltransferase 2B17 (UGT2B17 gene, in metabolising these compounds. This report postulates the association of deletion polymorphism in the UGT2B17 gene with the occurrence of renal disorders on chronic exposure to AAS. Presentation of the hypothesis The major deactivation and elimination pathway of AASs is through glucuronide conjugation, chiefly catalyzed by the UGT2B17 enzyme, followed by excretion in urine. Excretion of steroids is affected in individuals with a deletion mutation in the UGT2B17 gene. We hypothesize that UGT2B17 deficient individuals are more vulnerable to developing renal disorders with prolonged use of AAS owing to increases in body mass index and possible direct toxic effects of steroids on the kidneys. Elevated serum levels of biologically active steroids due to inadequate elimination can lead to prolonged muscle build up. An increase in body mass index may cause renal injuries due to sustained elevated glomerular pressure and flow rate. Testing the hypothesis In the absence of controlled clinical trials in humans, observational studies can be carried out. Real time PCR with allelic discrimination should be employed to examine the prevalence of different UGT2B17 genotypes in patients with impaired renal function and AAS abuse. In individuals with the UGT2B17 deletion polymorphism, blood tests, biofluid analyses, urinalysis, and hair analyses following the administration of an anabolic steroid can be used to determine the fate of the substance once in the body. Implications of the hypothesis If the hypothesis is upheld, anabolic steroid users with a deletion mutation in the UGT2B17 gene may be

  10. Relationship between the HLA-G 14 bp insertion/deletion polymorphism and susceptibility to autoimmune disease: a meta-analysis.

    Science.gov (United States)

    Kim, S K; Jeong, K H; Kang, I J; Chung, J H; Shin, M K; Lee, M H

    2015-12-03

    Numerous studies have investigated the potential relationship between the human leukocyte antigen (HLA)-G 14-bp insertion/deletion (INS/DEL) polymorphisms and autoimmune disease (AID). However, published results are inconclusive. Our aim was to determine whether the 14-bp INS/DEL polymorphism in the HLA-G gene contributes to the risk of AID. A systemic literature search of the PubMed and EMBASE databases was conducted to identify eligible studies investigating the association of the HLA-G 14-bp INS/DEL polymorphism with AID. Our analysis included 11 publications involving a total of 6462 individuals. Overall, no significant association between the HLA-G 14-bp INS/DEL polymorphism and AID was detected in any comparison model. Further subgroup analyses based on AID types and ethnicity also revealed no significant associations. Our results suggest that the HLA-G 14-bp INS/DEL polymorphism is unrelated to the development of AID. Further studies including larger sample sizes are warranted to confirm these results.

  11. The angiotensin-converting enzyme insertion/deletion polymorphism rs4340 associates with habitual physical activity among European American adults.

    Science.gov (United States)

    Bruneau, Michael; Angelopoulos, Theodore J; Gordon, Paul; Moyna, Niall; Visich, Paul; Zoeller, Robert; Seip, Rick; Bilbie, Stephen; Thompson, Paul; Devaney, Joseph; Gordish-Dressman, Heather; Hoffman, Eric; Pescatello, Linda S

    2017-09-01

    The angiotensin-converting enzyme (ACE) insertion/deletion (I/D) polymorphism (rs4340) (ACE DIP) accounts for half of the variability in plasma ACE concentrations. ACE has been widely studied for its influence on sports performance; however, research on its influence in physical activity is limited and inconsistent. We examined the influence of the ACE DIP on physical activity among 461 European Americans. Subjects completed the Paffenbarger Physical Activity Questionnaire for weekly walking distance. Multivariate analysis of covariance (MANCOVA) tested log-transformed differences in weekly walking distance among ACE DIP genotypes (II, ID, DD) with gender as a fixed factor, and age and body mass index (BMI) as covariates. Because we found a significant ACE DIPxBMI interaction (P = 0.03), we categorized the sample by normal weight (NW: BMIMANCOVA with multiple comparison adjustments. NW adults with ACE II walked 15.8 ± 11.1 km/week, ID 13.2 ± 10.6 km/week, and DD 17.9 ± 13.0 km/week, with ID walking less than II (P = 0.03) and DD (P = 0.01). OW adults with ACE II walked 16.7 ± 12.6 km/week, ID 13.8 ± 11.6 km/week, and DD 9.7 ± 9.0 km/week, with DD walking less than II (P = 0.02). Weekly walking distance was 8.2 ± 2.4 km/week less among OW adults with ACE DD than NW (P = 0.02). BMI interacted with ACE DD such that OW walked ~8.2 km/week less than NW, potentially equating to a body weight differential of ~3.5 kg annually.

  12. Insertion/deletion polymorphism in the angiotensin-I-converting enzyme gene is associated with coronary heart disease in IDDM patients with diabetic nephropathy

    DEFF Research Database (Denmark)

    Tarnow, L; Cambien, Francois; Rossing, P

    1995-01-01

    Insulin-dependent diabetic (IDDM) patients with diabetic nephropathy have a highly increased morbidity and mortality from coronary heart disease. An insertion (I) /deletion (D) polymorphism in the angiotensin-I-converting enzyme (ACE) gene has been shown to be associated with coronary heart disease...... regression analysis of the risk factors associated with coronary heart disease in univariate analysis revealed that the II genotype acts as an independent protective factor against coronary heart disease, odds ratio II/DD + ID 0.27 (95% confidence interval 0.07-0.97, p

  13. A closed-tube assay for genotyping of the 32-bp deletion polymorphism in the chemokine receptor 5 (CCR5) gene

    DEFF Research Database (Denmark)

    Rasmussen, Henrik Berg; Werge, Thomas

    2007-01-01

    in the presence of Sybr Green I for allele discrimination. After having established robust conditions for the assay, we used it to genotype 590 unknown DNA samples. A blinded comparison with a procedure based upon agarose gel electrophoresis of amplified material revealed complete concordance between the two...... procedures. Our closed-tube assay is inexpensive and easy to carry out. Furthermore, it reduces or eliminates the risk of carry-over contamination with previously amplified products. The insights gained in this study can be applied to develop assays for genotyping of other insertion/deletion polymorphisms...

  14. High-Frequency Seafloor Acoustics

    CERN Document Server

    Jackson, Darrell R

    2007-01-01

    High-Frequency Seafloor Acoustics is the first book in a new series sponsored by the Office of Naval Research on the latest research in underwater acoustics. This exciting new title provides ready access to experimental data, theory, and models relevant to high-frequency seafloor acoustics and will be of interest to sonar engineers and researchers working in underwater acoustics. The physical characteristics of the seafloor affecting acoustic propagation and scattering are covered, including physical and geoacoustic properties and surface roughness. Current theories for acoustic propagation in sediments are presented along with corresponding models for reflection, scattering, and seafloor penetration. The main text is backed up by an extensive bibliography and technical appendices.

  15. Quantitative assessment of the association between the angiotensin-converting enzyme gene insertion/deletion polymorphism and digestive system cancer risk.

    Science.gov (United States)

    Wang, J; Yang, S; Guo, F H; Mao, X; Zhou, H; Dong, Y Q; Wang, Z M; Luo, F

    2015-11-13

    The angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism has been reported to be associated with digestive system cancer; however, the results from previous studies have been conflicting. The present study aimed to investigate the association between the ACE I/D polymorphism and the risk of digestive system cancer using a meta-analysis of previously published studies. Databases were systematically searched to identify relevant studies published prior to December 2014. We estimated the pooled OR with its 95%CI to assess the association. The meta-analysis consisted of thirteen case-control studies that included 2557 patients and 4356 healthy controls. Meta-analysis results based on all the studies showed no significant association between the ACE I/D polymorphism and the risk of digestive system cancer (DD vs II: OR = 0.85, 95%CI = 0.59-1.24; DI vs II: OR = 0.94, 95%CI = 0.78-1.15; dominant model: OR = 0.96, 95%CI = 0.81- 1.15; recessive model: OR = 1.06, 95%CI = 0.76-1.48). Subgroup analyses by race and cancer type did not detect an association between the ACE I/D polymorphism and digestive system cancer risk. However, when the analyses were restricted to smaller studies (N digestive system cancer. Further large and well-designed studies are needed to confirm these conclusions.

  16. Angiotensin-converting enzyme insertion/deletion gene polymorphism in Egyptian children with systemic lupus erythematosus: a possible relation to proliferative nephritis.

    Science.gov (United States)

    Hammad, A; Yahia, S; Laimon, W; Hamed, S M; Shouma, A; Shalaby, N M; Abdel-Hady, D; Ghanem, R; El-Farahaty, R M; El-Bassiony, S R; Hammad, E M

    2017-06-01

    Introduction Angiotensin-converting enzyme (ACE) is crucial in the pathogenesis of systemic lupus erythematosus through angiotensin II which regulates vascular tone and endothelial functions. Objectives To study the frequency of ACE insertion/deletion (I/D) gene polymorphism in Egyptian children with systemic lupus erythematosus and its possible relation to the renal pathology in cases with lupus nephritis. Subjects and methods The frequency of ACE gene insertion/deletion polymorphism genotypes was determined in 78 Egyptian children with systemic lupus erythematosus and compared to a matched group of 140 healthy controls using polymerase chain reaction. Results The DD genotype of the ACE gene was higher in systemic lupus erythematosus patients when compared to controls ( Plupus erythematosus patients in comparison to controls ( P lupus nephritis group, the DD genotype was significantly higher in those with proliferative lupus nephritis when compared to those with non-proliferative lupus nephritis ( P = 0.02; OR = 1.45; 95% CI = 1.4-1.6). Also, patients with proliferative lupus nephritis showed a higher frequency of the D allele ( P lupus erythematosus and occurrence of proliferative nephritis in Egyptian children.

  17. High-frequency magnetic components

    CERN Document Server

    Kazimierczuk, Marian K

    2013-01-01

    A unique text on the theory and design fundaments of inductors and transformers, updated with more coverage on the optimization of magnetic devices and many new design examples The first edition is popular among a very broad audience of readers in different areas of engineering and science. This book covers the theory and design techniques of the major types of high-frequency power inductors and transformers for a variety of applications, including switching-mode power supplies (SMPS) and resonant dc-to-ac power inverters and dc-to-dc power converters. It describes eddy-current phenomena (su

  18. High-frequency complex pitch

    DEFF Research Database (Denmark)

    Santurette, Sébastien; Dau, Torsten

    2012-01-01

    Harmonics in a complex tone are typically considered unresolved when they interact with neighboring harmonics in the cochlea and cannot be heard out separately. Recent studies have suggested that the low pitch evoked by unresolved high-frequency harmonics may be coded via temporal fine-structure ......Harmonics in a complex tone are typically considered unresolved when they interact with neighboring harmonics in the cochlea and cannot be heard out separately. Recent studies have suggested that the low pitch evoked by unresolved high-frequency harmonics may be coded via temporal fine......-structure cues. However, these conclusions rely on the assumptions that combination tones were properly masked and that the ability of listeners to hear out individual partials provides an adequate measure of resolvability. Those assumptions were tested by measuring the audibility of combination tones...... and their effects on pitch matches, the effects of relative component phases and of dichotic presentation, and listeners' ability to hear out individual partials. The results confirmed that combination tones affected pitch, but pitch remained salient when they were masked. The lack of dependence of pitch...

  19. Detection of deletions at 7q11.23 in Williams-Beuren syndrome by polymorphic markers

    Directory of Open Access Journals (Sweden)

    Roberta Lelis Dutra

    2011-01-01

    Full Text Available INTRODUCTION: Williams-Beuren syndrome (WBS; OMIM 194050 is caused by a hemizygous contiguous gene microdeletion at 7q11.23. Supravalvular aortic stenosis, mental retardation, overfriendliness, and ocular and renal abnormalities comprise typical symptoms in WBS. Although fluorescence in situ hybridization is widely used for diagnostic confirmation, microsatellite DNA markers are considered highly informative and easily manageable. OBJECTIVES: This study aimed to test the microsatellite markers for the diagnosis of Williams-Beuren syndrome, to determine the size and parental origin of microdeletion, compare the clinical characteristics between patients with different sizes of the deletion and parental origin. METHODS: We studied 97 patients with clinical diagnosis of Williams-Beuren syndrome using five microsatellite markers: D7S1870, D7S489, D7S613, D7S2476 and D7S489_A. RESULTS AND DISCUSSION: Using five markers together, the result was informative in all patients. The most informative marker was D7S1870 (78.4%, followed by D7S613 (75.3%, D7S489 (70.1% and D7S2476 (62.9%. The microdeletion was present in 84 (86.6% patients and absent in 13 (13.4% patients. Maternal deletions were found in 52.4% of patients and paternal deletions in 47.6% of patients. The observed size of deletions was 1.55 Mb in 76/ 84 patients (90.5% and 1.84 Mb in 8/84 patients (9.5%. SVAS as well as ocular and urinary abnormalities were more frequent in the patients with a deletion. There were no clinical differences in relation to either the size or parental origin of the deletion. CONCLUSION: Using these five selected microsatellite markers was informative in all patients, thus can be considered an alternative method for molecular diagnosis in Williams-Beuren syndrome.

  20. Association of insertion/deletion polymorphism of angiotensin-converting enzyme gene among Malay male hypertensive subjects in response to ACE inhibitors.

    Science.gov (United States)

    Heidari, Farzad; Vasudevan, Ramachandran; Mohd Ali, Siti Zubaidah; Ismail, Patimah; Etemad, Ali; Pishva, Seyyed Reza; Othman, Fauziah; Abu Bakar, Suhaili

    2015-12-01

    Several studies show that the insertion/deletion (I/D) polymorphism of the angiotensin-converting enzyme (ACE) gene has been associated with hypertension in various populations. The present study sought to determine the association of the I/D gene polymorphism among Malay male essential hypertensive subjects in response to ACE inhibitors (enalapril and lisinopril). A total of 72 patients with newly diagnosed hypertension and 72 healthy subjects were recruited in this study. Blood pressure was recorded from 0 to 24 weeks of treatment with enalapril or lisinopril. Genotyping of the I/D polymorphism was carried out using a standard PCR method. Statistically significant association of the D allele of the ACE gene was observed between the case and control subjects (p ACE gene. Patients carrying the DD genotype had higher blood pressure-lowering response when treated with ACE inhibitors enalapril or lisinopril than those carrying ID and II genotypes, suggesting that the D allele may be a possible genetic marker for essential hypertension among Malay male subjects. © The Author(s) 2014.

  1. Association between human leukocyte antigen-G 14-bp insertion/deletion polymorphism and cancer risk: a meta-analysis and systematic review.

    Science.gov (United States)

    Ge, Yu-Zheng; Ge, Qian; Li, Ming-Hao; Shi, Guo-Mei; Xu, Xiao; Xu, Lu-Wei; Xu, Zheng; Lu, Tian-Ze; Wu, Ran; Zhou, Liu-Hua; Wu, Jian-Ping; Liang, Kai; Dou, Quan-Liang; Zhu, Jia-Geng; Li, Wen-Cheng; Jia, Rui-Peng

    2014-08-01

    Human leukocyte antigen-G (HLA-G) is involved in the development and progression of human cancers, and numerous molecular epidemiological studies have been conducted to explore the potential relationship of HLA-G 14-bp insertion/deletion (ins/del) polymorphism with cancer risk. However, results from published studies were inconclusive. Both PUBMED and EMBASE databases were searched comprehensively to identify eligible studies investigating the association of HLA-G 14-bp ins/del polymorphism with cancer risk. Statistical analysis was performed by using STATA 12.0 and Review Manager 5.0. Fourteen eligible studies with 2340 cancer patients and 3967 controls were included and analyzed with odds ratio (OR) and its corresponding 95% confidence interval (CI). Overall, no significant association between HLA-G 14-bp ins/del polymorphism and overall cancer risk was detected in all comparison models. Further subgroup analyses based on ethnicity and cancer types demonstrated the significant association among Asians (ins/del vs. del/del: OR = 0.80, 95% CI, 0.66-0.95; ins/ins+ins/del vs. del/del: OR = 0.80, 95% CI, 0.65-0.97) and for breast cancer (ins allele vs. del allele: OR = 0.76, 95% CI, 0.61-0.96; ins/ins vs. del/del: OR = 0.57, 95% CI, 0.37-0.87; and ins/ins vs. ins/del+del/del: OR = 0.60, 95% CI, 0.42-0.87). This study suggested that HLA-G 14-bp ins/del polymorphism might contribute to breast cancer susceptibility and overall cancer risk among Asians. Further well-designed studies with larger sample size are warranted to validate our conclusion. Copyright © 2014 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.

  2. Association of Angiotensin Converting Enzyme Insertion-Deletion Polymorphism with Hypertension in Emiratis with Type 2 Diabetes Mellitus and Its Interaction with Obesity Status.

    Science.gov (United States)

    Alsafar, Habiba; Hassoun, Ahmed; Almazrouei, Shaikha; Kamal, Wala; Almaini, Mustafa; Odama, Unini; Rais, Naushad

    2015-01-01

    The association of Angiotensin Converting Enzyme (ACE) insertion-deletion (I/D) polymorphism with Type 2 Diabetes Mellitus (T2DM) and hypertension has been extensively studied throughout various ethnic populations but largely with inconsistent findings. We investigated these associations in Emirati population and their interaction with obesity status. Saliva samples were collected from a total of 564 Emiratis (277 T2DM and 297 healthy). DNA was extracted and the samples were genotyped for ACE I/D polymorphism by a PCR based method followed by gel electrophoresis. Upon evaluation of the ACE I/D polymorphism amongst all T2DM, hypertensive patients, and respective controls regardless of obesity status, ACE DD genotype was not found to be associated with either T2DM [odds ratio (OR) = 1.34, p = 0.086] or hypertension [odd ratio (OR) = 1.02, p = 0.93]. When the genetic variants amongst the nonobese and obese population were analyzed separately, the risk genotype ACE DD conferred significantly increased risk of hypertension in nonobese population [odds ratio (OR) = 1.80, p = 0.02] but was found to be protective against the hypertension in the obese group ((OR) = 0.54, p = 0.01). However, there was no effect of obesity status on the association of ACE genotypes with T2DM. The risk of hypertension associated with ACE DD is modulated by obesity status and hence future genetic association studies should take obesity into account for the interpretation of data. We also confirmed that ACE I/D polymorphism is not associated with T2DM risk in Emirati population.

  3. Econometrics of financial high-frequency data

    CERN Document Server

    Hautsch, Nikolaus

    2011-01-01

    This book covers major approaches in high-frequency econometrics. It discusses implementation details, provides insights into properties of high-frequency data as well as institutional settings and presents applications.

  4. Association Between Plasminogen Activator Inhibitor-1-675 4G/5G Insertion/Deletion Polymorphism and Chronic Obstructive Pulmonary Disease.

    Science.gov (United States)

    Essa, Enas S; El Wahsh, Rabab A

    2016-12-01

    Molecular pathology of chronic obstructive pulmonary disease (COPD) is still being investigated to discover relationships with disease pathogenesis. Evidence of plasminogen activator inhibitor-1 (PAI-1) overexpression in the sputum and the blood of COPD patients is growing. We aimed to investigate the potential relation between PAI-1 promoter 4G/5G insertion/deletion polymorphism and COPD development. In a case-control study, we genotyped 117 COPD patients and 160 control subjects for PAI-1 promoter 4G/5G polymorphism by an allele-specific polymerase chain reaction analysis. All subjects were male smokers. In the co-dominant model, there was a significant difference in the distribution of 5G/5G, 4G/5G and 4G/4G genotypes between COPD patients and controls (p = 0.002). In the recessive model, carriers of 4G/4G genotype were significantly higher in COPD patients than controls (p = 0.01). Carriers of 4G/4G genotype were at higher risk to develop COPD than those carrying 5G/5G or 4G/5G genotypes (crude odds ratio (OR) = 2.10, 95% confidence interval (CI) = 1.19-3.73, adjusted OR = 2.5, 95% CI = 1.22-3.99). In conclusion, PAI-1 4G/5G genetic variations are associated with COPD development in males.

  5. An HLA-G(∗)14bp insertion/deletion polymorphism associates with the development of autistic spectrum disorders.

    Science.gov (United States)

    Guerini, Franca R; Bolognesi, Elisabetta; Chiappedi, Matteo; Ghezzo, Alessandro; Canevini, Maria Paola; Mensi, Martina M; Vignoli, Aglaia; Agliardi, Cristina; Zanette, Michela; Clerici, Mario

    2015-02-01

    HLA-G expressed by the trophoblast ligates KIR molecules expressed by maternal NK cells at the uterine fetal/maternal interface: this interaction is involved in generating immune tolerance during pregnancy. A 14-bp insertion in the HLA-G 3'-UTR associates with significantly reduced levels of both HLA-G mRNA and soluble HLA-G, thus hampering the efficacy of HLA-G-mediated immune tolerance during pregnancy. Because prenatal immune activation is suggested to play an important role in the onset of autistic spectrum disorders (ASD) we performed an in-depth evaluation of HLA-G polymorphisms in a well-characterized cohort of Italian families of ASD children. Results showed that frequency of both homozygous 14bp+/14bp+ genotype and 14bp+ allele was significantly higher in ASD children and their mothers compared to controls (panalysis of the frequency of transmission of the 14bp+ allele from parents to ASD children and their non-ASD siblings showed that the 14bp+ allele was more frequently transmitted (T) to ASD children, whereas it was preferentially not transmitted (NT) to the non-ASD siblings (overall discrepancy: p=0.02; OR: 2.6, 95% CI: 1.1-6.4). Results herein suggest that HLA-G polymorphisms are associated with ASD development, possibly as a consequence of prenatal immune activation. These data infer that the immune alterations seen in ASD are associated with the maternal-fetal interaction alone, and reinforce the observation that different genetic backgrounds characterize ASD children and their non-ASD siblings. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Prevalence of angiotensin converting enzyme (ACE gene insertion/deletion polymorphism in South Indian population with hypertension and chronic kidney disease

    Directory of Open Access Journals (Sweden)

    R Shanmuganathan

    2015-01-01

    Full Text Available Context: Chronic Kidney Disease (CKD is associated with a high risk of developing further severe complications such as, cardiovascular disease and eventually End Stage Renal Disease (ESRD leading to death. Hypertension plays a key role in the progression of renal failure and is also a chief risk factor for the occurrence of End Stage Renal Disease (ESRD. Aim: This study investigates the possible association of insertion (I and deletion (D polymorphism of ACE gene in patients of Chronic Kidney Disease (CKD with and without hypertension (HT. Settings and Design: Total 120 participants with 30 members in each group (Control, HT, CKD and CKD-HT were chosen followed by informed consent. Materials and Methods: Blood samples were collected and subjected to biochemical analyses and nested PCR amplification was performed to genotype the DNA, for ACE I/D using specific primers. Statistical Analysis: Statistical analyses were performed using SPSS version 13. Allele and genotypic frequency was calculated by direct gene counting method. Comparison of the different genotypes was done by using Chi square test. Odd′s ratios were calculated with a 95% confidence interval limit. Results: The ACE genotype were distributed as II, 27 (90%; DD, 2 (6.67% and ID, 1 (3.33% in control, II, 1 (3.33%; DD, 5 (16.67% and ID, 24 (80% in HT, II, 4 (13.33%; DD, 24 (80% and ID, 2 (6.67% in CKD and II, 0 (0%; DD, 2 (6.67% and ID, 28 (93.33% in CKD-HT group. Conclusions: D allele of ACE gene confers a greater role in genetic variations underlying CKD and hypertension. This result suggest that CKD patients should be offered analysis for defects in ACE I/D polymorphisms, especially if they are hypertensive.

  7. Associations of ACE Gene Insertion/Deletion Polymorphism, ACE Activity, and ACE mRNA Expression with Hypertension in a Chinese Population

    Science.gov (United States)

    He, Qingfang; Fan, Chunhong; Yu, Min; Wallar, Gina; Zhang, Zuo-Feng; Wang, Lixin; Zhang, Xinwei; Hu, Ruying

    2013-01-01

    Background The present study was designed to explore the association of angiotensin converting enzyme (ACE) gene insertion/deletion (I/D, rs4646994) polymorphism, plasma ACE activity, and circulating ACE mRNA expression with essential hypertension (EH) in a Chinese population. In addition, a new detection method for circulating ACE mRNA expression was explored. Methods The research was approved by the ethics committee of Zhejiang Provincial Center for Disease Prevention and Control. Written informed consent was obtained prior to the investigation. 221 hypertensives (cases) and 221 normotensives (controls) were interviewed, subjected to a physical examination, and provided blood for biochemical and genetic tests. The ACE mRNA expression was analyzed by real time fluorescent quantitative Reverse Transcription PCR (FQ-RT-PCR). We performed logistic regression to assess associations of ACE I/D genotypes, ACE activity, and ACE mRNA expression levels with hypertension. Results The results of the multivariate logistic regression analysis showed that the additive model (ID, DD versus II) of the ACE genotype revealed an association with hypertension with adjusted OR of 1.43(95% CI: 1.04-1.97), and ACE ID genotype with adjusted OR of 1.72(95% CI: 1.01-2.92), DD genotype with adjusted OR of 1.94(95% CI: 1.01-3.73), respectively. In addition, our data also indicate that plasma ACE activity (adjusted OR was 1.13(95% CI: 1.08-1.18)) was significantly related to hypertension. However, the plasma ACE mRNA expressions were not different between the cases and controls. Conclusion ACE I/D polymorphism and ACE activity revealed significant influence on hypertension, while circulating ACE mRNA expression was not important factors associated with hypertension in this Chinese population. The detection of circulating ACE mRNA expression by FQ-RT-PCR might be a useful method for early screening and monitoring of EH. PMID:24098401

  8. Overview of the Advanced High Frequency Branch

    Science.gov (United States)

    Miranda, Felix A.

    2015-01-01

    This presentation provides an overview of the competencies, selected areas of research and technology development activities, and current external collaborative efforts of the NASA Glenn Research Center's Advanced High Frequency Branch.

  9. The relationship between angiotensin-converting enzyme gene insertion/deletion polymorphism and digestive cancer risk: Insights from a meta-analysis.

    Science.gov (United States)

    Yang, Hualing; Cai, Chengfu; Ye, Linyang; Rao, Yiqing; Wang, Qingxiang; Hu, Dan; Huang, Xi

    2015-12-01

    The gene encoding angiotensin-converting enzyme (ACE) has been implicated in the development of several malignancies. We aimed to meta-analyze the association of ACE gene insertion/deletion (I/D) polymorphism with digestive cancer risk and seek possible sources of between-study heterogeneity. Two authors independently assessed eligibility of each retrieved publication and gathered relevant data. Risk estimates were expressed as odds ratio (OR) and 95% confidence interval (CI). Sixteen publications were qualified for analysis, involving 2903 digestive cancer cases and 10,833 controls. Overall analyses failed to show any significance for digestive cancer risk. There was moderate heterogeneity and lower publication bias for overall comparisons. In subgroup analyses, ACE gene II genotype was associated with a 15% reduced risk (OR=0.85, 95% CI: 0.57-1.27, p=0.434) for gastric cancer, but a 16% increased risk (OR=1.16, 95% CI: 0.89-1.52, p=0.273) for colorectal cancer. By source of controls, the I allele appeared to be a protective factor against digestive cancer in population-based studies (OR=0.87, 95% CI: 0.75-1.00, p=0.055) but a risk-conferring factor in hospital-based studies (OR=1.17, 95% CI: 1.01-1.35, p=0.033). Our findings suggested that ACE gene I allele might be a protective factor against gastric cancer, necessitating further confirmation in large, population-based studies. © The Author(s) 2015.

  10. Application of real-time PCR of sex-independent insertion-deletion polymorphisms to determine fetal sex using cell-free fetal DNA from maternal plasma.

    Science.gov (United States)

    Ho, Sherry Sze Yee; Barrett, Angela; Thadani, Henna; Asibal, Cecille Laureano; Koay, Evelyn Siew-Chuan; Choolani, Mahesh

    2015-07-01

    Prenatal diagnosis of sex-linked disorders requires invasive procedures, carrying a risk of miscarriage of up to 1%. Cell-free fetal DNA (cffDNA) present in cell-free DNA (cfDNA) from maternal plasma offers a non-invasive source of fetal genetic material for analysis. Detection of Y-chromosome sequences in cfDNA indicates presence of a male fetus; in the absence of a Y-chromosome signal a female fetus is inferred. We aimed to validate the clinical utility of insertion-deletion polymorphisms (INDELs) to confirm presence of a female fetus using cffDNA. Quantitative real-time PCR (qPCR) for the Y-chromosome-specific sequence, SRY, was performed on cfDNA from 82 samples at 6-39 gestational weeks. In samples without detectable SRY, qPCRs for eight INDELs were performed on maternal genomic DNA and cfDNA. Detection of paternally inherited fetal alleles in cfDNA negative for SRY confirmed a female fetus. Fetal sex was correctly determined in 77/82 (93.9%) cfDNA samples. SRY was detected in all 39 samples from male-bearing pregnancies, and none of the 43 female-bearing pregnancies (sensitivity and specificity of SRY qPCR is therefore 100%; 95% CI 91%-100%). Paternally inherited fetal alleles were detected in 38/43 samples with no SRY signal, confirming the presence of a female fetus (INDEL assay sensitivity is therefore 88.4%; 95% CI 74.1%-95.6%). Since paternally inherited fetal INDELs were not used in women bearing male fetuses, the specificity of INDELs cannot be calculated. Five cfDNA samples were negative for both SRY and INDELS. We have validated a non-invasive prenatal test to confirm fetal sex as early as 6 gestational weeks using cffDNA from maternal plasma.

  11. QualitySNP: a pipeline for detecting single nucleotide polymorphisms and insertions/deletions in EST data from diploid and polyploid species

    Directory of Open Access Journals (Sweden)

    Voorrips Roeland E

    2006-10-01

    Full Text Available Abstract Background Single nucleotide polymorphisms (SNPs are important tools in studying complex genetic traits and genome evolution. Computational strategies for SNP discovery make use of the large number of sequences present in public databases (in most cases as expressed sequence tags (ESTs and are considered to be faster and more cost-effective than experimental procedures. A major challenge in computational SNP discovery is distinguishing allelic variation from sequence variation between paralogous sequences, in addition to recognizing sequencing errors. For the majority of the public EST sequences, trace or quality files are lacking which makes detection of reliable SNPs even more difficult because it has to rely on sequence comparisons only. Results We have developed a new algorithm to detect reliable SNPs and insertions/deletions (indels in EST data, both with and without quality files. Implemented in a pipeline called QualitySNP, it uses three filters for the identification of reliable SNPs. Filter 1 screens for all potential SNPs and identifies variation between or within genotypes. Filter 2 is the core filter that uses a haplotype-based strategy to detect reliable SNPs. Clusters with potential paralogs as well as false SNPs caused by sequencing errors are identified. Filter 3 screens SNPs by calculating a confidence score, based upon sequence redundancy and quality. Non-synonymous SNPs are subsequently identified by detecting open reading frames of consensus sequences (contigs with SNPs. The pipeline includes a data storage and retrieval system for haplotypes, SNPs and alignments. QualitySNP's versatility is demonstrated by the identification of SNPs in EST datasets from potato, chicken and humans. Conclusion QualitySNP is an efficient tool for SNP detection, storage and retrieval in diploid as well as polyploid species. It is available for running on Linux or UNIX systems. The program, test data, and user manual are available at

  12. High frequency and pulse scattering physical acoustics

    CERN Document Server

    Pierce, Allan D

    1992-01-01

    High Frequency and Pulse Scattering investigates high frequency and pulse scattering, with emphasis on the phenomenon of echoes from objects. Geometrical and catastrophe optics methods in scattering are discussed, along with the scattering of sound pulses and the ringing of target resonances. Caustics and associated diffraction catastrophes are also examined.Comprised of two chapters, this volume begins with a detailed account of geometrically based approximation methods in scattering theory, focusing on waves transmitted through fluid and elastic scatterers and glory scattering; surface ray r

  13. A gender-moderated effect of a functional COMT polymorphism on prefrontal brain morphology and function in velo-cardio-facial syndrome (22q11.2 deletion syndrome).

    Science.gov (United States)

    Kates, Wendy R; Antshel, Kevin M; Abdulsabur, Nuria; Colgan, Deirdre; Funke, Birgit; Fremont, Wanda; Higgins, Anne Marie; Kucherlapati, Raju; Shprintzen, Robert J

    2006-04-05

    Caused by a microdeletion at the q11.2 locus of chromosome 22, velo-cardio-facial syndrome (also known as VCFS, 22q11 deletion syndrome, DiGeorge sequence, and conotruncal anomalies face syndrome) is associated with a distinctive physical, neurocognitive, and psychiatric phenotype. Increasing interest has centered on identifying the candidate genes within the deleted region that may contribute to this phenotype. One attractive candidate gene is catechol-O-methyltransferase (COMT) because it encodes for a protein that degrades dopamine. Variability in COMT activity is related to a Val158Met polymorphism that has been implicated in prefrontal lobe cognitive and neuropsychiatric function. We examined the effect of this polymorphism on prefrontal anatomy and frontally-mediated neuropsychological function in 58 children with VCFS, 26 who were hemizygous for the Met allele and 32 for the Val allele. We found an allele by gender interaction effect on the volumes of the dorsal prefrontal and orbital prefrontal cortices. We did not find significant allele or gender by allele effects on neuropsychological tasks, although girls with the Met allele tended to perform better on the Wisconsin card sorting task. These data suggest that this functional COMT polymorphism may play a gender-moderated role in determining the neuroanatomic phenotype of individuals with VCFS. Longitudinal evaluation of these children is essential in order to identify potential clinical implications of this allele by gender interaction. Copyright 2006 Wiley-Liss, Inc.

  14. High frequency pressure oscillator for microcryocoolers

    NARCIS (Netherlands)

    Vanapalli, Srinivas; ter Brake, Hermanus J.M.; Jansen, Henricus V.; Zhao, Yiping; Holland, Herman J.; Burger, Johannes Faas; Elwenspoek, Michael Curt

    2008-01-01

    Microminiature pulse tube cryocoolers should operate at a frequency of an order higher than the conventional macro ones because the pulse tube cryocooler operating frequency scales inversely with the square of the pulse tube diameter. In this paper, the design and experiments of a high frequency

  15. High frequency pressure oscillator for microcryocoolers

    Science.gov (United States)

    Vanapalli, S.; ter Brake, H. J. M.; Jansen, H. V.; Zhao, Y.; Holland, H. J.; Burger, J. F.; Elwenspoek, M. C.

    2008-04-01

    Microminiature pulse tube cryocoolers should operate at a frequency of an order higher than the conventional macro ones because the pulse tube cryocooler operating frequency scales inversely with the square of the pulse tube diameter. In this paper, the design and experiments of a high frequency pressure oscillator is presented with the aim to power a micropulse tube cryocooler operating between 300 and 80K, delivering a cooling power of 10mW. Piezoelectric actuators operate efficiently at high frequencies and have high power density making them good candidates as drivers for high frequency pressure oscillator. The pressure oscillator described in this work consists of a membrane driven by a piezoelectric actuator. A pressure ratio of about 1.11 was achieved with a filling pressure of 2.5MPa and compression volume of about 22.6mm3 when operating the actuator with a peak-to-peak sinusoidal voltage of 100V at a frequency of 1kHz. The electrical power input was 2.73W. The high pressure ratio and low electrical input power at high frequencies would herald development of microminiature cryocoolers.

  16. Investigation of deletions at 7q11.23 in 44 patients referred for Williams-Beuren syndrome, using FISH and four DNA polymorphisms

    DEFF Research Database (Denmark)

    Brøndum-Nielsen, K; Beck, B; Gyftodimou, J

    1997-01-01

    Williams syndrome (WS) is associated with a submicroscopic deletion of the elastin gene (ELN) at 7q11.23. The deletion encompasses closely linked DNA markers. We have investigated 44 patients referred for possible WS using fluorescence in situ hybridization (FISH) analysis with a P1 clone...

  17. Advances in Very High Frequency Power Conversion

    DEFF Research Database (Denmark)

    Kovacevic, Milovan

    . Excellent performance and small size of magnetic components and capacitors at very high frequencies, along with constant advances in performance of power semiconductor devices, suggests a sizable shift in consumer power supplies market into this area in the near future. To operate dc-dc converter power...... devices at very high frequencies, switching loss needs to reduced or eliminated, as it would become prohibitively large. In addition, as the frequency increases, hard-switched gate driving becomes less and less of an option, as it embodies the same loss mechanism. A low-loss gate drive methods may need...... drive solution, which is applicable in cases when there are at least two power stages, and with minimal additional hardware requirements. It is experimentally confirmed that the method is suitable for both parallel and serial input configurations. Compared to state-of-the-art solutions, the proposed...

  18. High frequency conductivity in carbon nanotubes

    Directory of Open Access Journals (Sweden)

    S. S. Abukari

    2012-12-01

    Full Text Available We report on theoretical analysis of high frequency conductivity in carbon nanotubes. Using the kinetic equation with constant relaxation time, an analytical expression for the complex conductivity is obtained. The real part of the complex conductivity is initially negative at zero frequency and become more negative with increasing frequency, until it reaches a resonance minimum at ω ∼ ωB for metallic zigzag CNs and ω < ωB for armchair CNs. This resonance enhancement is indicative for terahertz gain without the formation of current instabilities induced by negative dc conductivity. We noted that due to the high density of states of conduction electrons in metallic zigzag carbon nanotubes and the specific dispersion law inherent in hexagonal crystalline structure result in a uniquely high frequency conductivity than the corresponding values for metallic armchair carbon nanotubes. We suggest that this phenomenon can be used to suppress current instabilities that are normally associated with a negative dc differential conductivity.

  19. High frequency pressure oscillator for microcryocoolers

    OpenAIRE

    Vanapalli, Srinivas; ter Brake, Hermanus J.M.; Jansen, Henricus V.; Zhao, Yiping; Holland, Herman J.; Burger, Johannes Faas; Elwenspoek, Michael Curt

    2008-01-01

    Microminiature pulse tube cryocoolers should operate at a frequency of an order higher than the conventional macro ones because the pulse tube cryocooler operating frequency scales inversely with the square of the pulse tube diameter. In this paper, the design and experiments of a high frequency pressure oscillator is presented with the aim to power a micropulse tube cryocooler operating between 300 and 80 K, delivering a cooling power of 10 mW. Piezoelectric actuators operate efficiently at ...

  20. High frequency impedances in European XFEL

    Energy Technology Data Exchange (ETDEWEB)

    Dohlus, Martin; Zagorodnov, Igor; Zagorodnova, Olga

    2010-06-15

    The method of the optical approximation is used to estimate the high frequency impedances of different vacuum chamber transitions of the European XFEL beam line. The approximations of the longitudinal impedances are obtained in terms of simple one-dimensional integrals. The transverse impedances are written in analytical closed form. The analytical results are compared with the results obtained by numerical solution of Maxwell's equations. (orig.)

  1. Novel high-frequency air transducers

    Science.gov (United States)

    Schiller, S.; Hsieh, C.-K.; Chou, C.-H.; Khuri-Yakub, B. T.

    The properties of ligneous materials have been evaluated in order to improve the insertion loss and bandwidth of air-based ultrasonic transducers. It is found that cork and balsa wood have the appropriate impedance to match with air, though their attenuation coefficients are prohibitive for high-frequency operation. For multiple matching layer devices, ligneous materials could be made useful in the 1-10 MHz frequency range.

  2. High Frequency Guided Wave Virtual Array SAFT

    Science.gov (United States)

    Roberts, R.; Pardini, A.; Diaz, A.

    2003-03-01

    The principles of the synthetic aperture focusing technique (SAFT) are generalized for application to high frequency plate wave signals. It is shown that a flaw signal received in long-range plate wave propagation can be analyzed as if the signals were measured by an infinite array of transducers in an unbounded medium. It is shown that SAFT-based flaw sizing can be performed with as few as three or less actual measurement positions.

  3. High-Frequency Percussive Ventilation Revisited

    Science.gov (United States)

    2010-01-01

    Landstuhl Regional Medical Center, Germany; and †United States Army Institute of Surgical Research, Fort Sam Houston, Texas. The author does not have...AND ADDRESS(ES) United States Army Institute of Surgical Research, JBSA Fort Sam Houston, TX 8. PERFORMING ORGANIZATION REPORT NUMBER 9...Engl J Med 1981;305:1375–9. 25. Pillow JJ. High-frequency oscillatory ventilation: mecha- nisms of gas exchange and lung mechanics. Crit Care Med

  4. Extremely high frequency RF effects on electronics.

    Energy Technology Data Exchange (ETDEWEB)

    Loubriel, Guillermo Manuel; Vigliano, David; Coleman, Phillip Dale; Williams, Jeffery Thomas; Wouters, Gregg A.; Bacon, Larry Donald; Mar, Alan

    2012-01-01

    The objective of this work was to understand the fundamental physics of extremely high frequency RF effects on electronics. To accomplish this objective, we produced models, conducted simulations, and performed measurements to identify the mechanisms of effects as frequency increases into the millimeter-wave regime. Our purpose was to answer the questions, 'What are the tradeoffs between coupling, transmission losses, and device responses as frequency increases?', and, 'How high in frequency do effects on electronic systems continue to occur?' Using full wave electromagnetics codes and a transmission-line/circuit code, we investigated how extremely high-frequency RF propagates on wires and printed circuit board traces. We investigated both field-to-wire coupling and direct illumination of printed circuit boards to determine the significant mechanisms for inducing currents at device terminals. We measured coupling to wires and attenuation along wires for comparison to the simulations, looking at plane-wave coupling as it launches modes onto single and multiconductor structures. We simulated the response of discrete and integrated circuit semiconductor devices to those high-frequency currents and voltages, using SGFramework, the open-source General-purpose Semiconductor Simulator (gss), and Sandia's Charon semiconductor device physics codes. This report documents our findings.

  5. High Frequency Components in Bottlenose Dolphin Echolocation Signals

    National Research Council Canada - National Science Library

    Toland, Ronald

    1998-01-01

    .... To assess the importance of these high frequencies in dolphin echolocation and target identification, experiments were performed in which an acoustic filter, used to suppress the high frequencies...

  6. High-frequency Rayleigh-wave method

    Science.gov (United States)

    Xia, J.; Miller, R.D.; Xu, Y.; Luo, Y.; Chen, C.; Liu, J.; Ivanov, J.; Zeng, C.

    2009-01-01

    High-frequency (???2 Hz) Rayleigh-wave data acquired with a multichannel recording system have been utilized to determine shear (S)-wave velocities in near-surface geophysics since the early 1980s. This overview article discusses the main research results of high-frequency surface-wave techniques achieved by research groups at the Kansas Geological Survey and China University of Geosciences in the last 15 years. The multichannel analysis of surface wave (MASW) method is a non-invasive acoustic approach to estimate near-surface S-wave velocity. The differences between MASW results and direct borehole measurements are approximately 15% or less and random. Studies show that simultaneous inversion with higher modes and the fundamental mode can increase model resolution and an investigation depth. The other important seismic property, quality factor (Q), can also be estimated with the MASW method by inverting attenuation coefficients of Rayleigh waves. An inverted model (S-wave velocity or Q) obtained using a damped least-squares method can be assessed by an optimal damping vector in a vicinity of the inverted model determined by an objective function, which is the trace of a weighted sum of model-resolution and model-covariance matrices. Current developments include modeling high-frequency Rayleigh-waves in near-surface media, which builds a foundation for shallow seismic or Rayleigh-wave inversion in the time-offset domain; imaging dispersive energy with high resolution in the frequency-velocity domain and possibly with data in an arbitrary acquisition geometry, which opens a door for 3D surface-wave techniques; and successfully separating surface-wave modes, which provides a valuable tool to perform S-wave velocity profiling with high-horizontal resolution. ?? China University of Geosciences (Wuhan) and Springer-Verlag GmbH 2009.

  7. The LASI high-frequency ellipticity system

    Energy Technology Data Exchange (ETDEWEB)

    Sternberg, B.K.; Poulton, M.M. [Univ. of Arizona, Tucson, AZ (United States)

    1995-10-01

    A high-frequency, high-resolution, electromagnetic (EM) imaging system has been developed for environmental geophysics surveys. Some key features of this system include: (1) rapid surveying to allow dense spatial sampling over a large area, (2) high-accuracy measurements which are used to produce a high-resolution image of the subsurface, (3) measurements which have excellent signal-to-noise ratio over a wide bandwidth (31 kHz to 32 MHz), (4) large-scale physical modeling to produce accurate theoretical responses over targets of interest in environmental geophysics surveys, (5) rapid neural network interpretation at the field site, and (6) visualization of complex structures during the survey.

  8. Cultures of High-frequency Trading

    DEFF Research Database (Denmark)

    Lange, Ann-Christina; Lenglet, Marc; Seyfert, Robert

    2016-01-01

    As part of ongoing work to lay a foundation for social studies of high-frequency trading (HFT), this paper introduces the culture(s) of HFT as a sociological problem relating to knowledge and practice. HFT is often discussed as a purely technological development, where all that matters is the speed...... of allocating, processing and transmitting data. Indeed, the speed at which trades are executed and data transmitted is accelerating, and it is fair to say that algorithms are now the primary interacting agents operating in the financial markets. However, we contend that HFT is first and foremost a cultural...

  9. Genetic instability and intratumoral heterogeneity in neuroblastoma with MYCN amplification plus 11q deletion.

    Directory of Open Access Journals (Sweden)

    Eva Villamón

    Full Text Available Genetic analysis in neuroblastoma has identified the profound influence of MYCN amplification and 11q deletion in patients' prognosis. These two features of high-risk neuroblastoma usually occur as mutually exclusive genetic markers, although in rare cases both are present in the same tumor. The purpose of this study was to characterize the genetic profile of these uncommon neuroblastomas harboring both these high-risk features.We selected 18 neuroblastomas with MNA plus 11q loss detected by FISH. Chromosomal aberrations were analyzed using Multiplex Ligation-dependent Probe Amplification and Single Nucleotide Polymorphism array techniques.This group of tumors has approximately the same high frequency of aberrations as found earlier for 11q deleted tumors. In some cases, DNA instability generates genetic heterogeneity, and must be taken into account in routine genetic diagnosis.

  10. The effects of gender and catechol O-methyltransferase (COMT) Val108/158Met polymorphism on emotion regulation in velo-cardio-facial syndrome (22q11.2 deletion syndrome): An fMRI study.

    Science.gov (United States)

    Coman, Ioana L; Gnirke, Matthew H; Middleton, Frank A; Antshel, Kevin M; Fremont, Wanda; Higgins, Anne Marie; Shprintzen, Robert J; Kates, Wendy R

    2010-11-15

    Velo-cardio-facial syndrome (VCFS) is caused by a micro-deletion of over 40 genes at the q11.2 locus of chromosome 22 and is a risk factor for the development of schizophrenia and other psychiatric disorders. COMT, one of the genes located in the deleted region, has been considered as a major candidate gene for genetic susceptibility in psychiatric diseases. Its functional polymorphism Val108/158Met has been shown to affect prefrontal function and working memory and has been associated with emotional dysregulation. We utilized a functional magnetic resonance imaging (fMRI) event-related paradigm to asses COMT genotype and gender-moderated effects on the neural activation that are elicited by viewing emotionally salient images charged with pleasant, unpleasant, and neutral content. Since estrogen down-regulates COMT activity resulting in lower COMT activity in women than men, we hypothesized an allele-by-gender interaction effect on neural activation. Participants included 43 VCFS individuals (Val/male=9, Val/female=17, Met/male=9, Met/female=8). We observed a gender effect on processing positive emotions, in that girls activated the cingulate gyrus more than boys did. We further observed a significant gender-by-allele interaction effect on neural function specific to the frontal lobe during the processing of pleasant stimuli, and specific to limbic regions during the processing of unpleasant stimuli. Our results suggest that in VCFS, the effect of the COMT Val108/158Met polymorphism is moderated by gender during the processing of emotional stimuli and could contribute to the understanding of the way in which this COMT polymorphism affects vulnerability to neuropsychiatric disorders. Copyright 2010 Elsevier Inc. All rights reserved.

  11. Insertion/deletion polymorphism of the angiotensin-converting enzyme gene and the risk of hypertension among residents of two cities, South-South Nigeria

    Directory of Open Access Journals (Sweden)

    Mary Esien Kooffreh

    2014-01-01

    Conclusion: The I/D polymorphism of the angiotensin-converting enzyme gene was a risk factor for hypertension in the sample population of Calabar and Uyo. This research will form baseline information for subsequent molecular studies in this population.

  12. CYP2D6 worldwide genetic variation shows high frequency of altered activity variants and no continental structure.

    Science.gov (United States)

    Sistonen, Johanna; Sajantila, Antti; Lao, Oscar; Corander, Jukka; Barbujani, Guido; Fuselli, Silvia

    2007-02-01

    CYP2D6, a member of the cytochrome P450 superfamily, is responsible for the metabolism of about 25% of the commonly prescribed drugs. Its activity ranges from complete deficiency to excessive activity, potentially causing toxicity of medication or therapeutic failure with recommended drug dosages. This study aimed to describe the CYP2D6 diversity at the global level. A total of 1060 individuals belonging to 52 worldwide-distributed populations were genotyped at 12 highly informative variable sites, as well as for gene deletion and duplications. Phenotypes were predicted on the basis of haplotype combinations. Our study shows that (i) CYP2D6 diversity is far greater within than between populations and groups thereof, (ii) null or low-activity variants occur at high frequencies in various areas of the world, (iii) linkage disequilibrium is lowest in Africa and highest in the Americas. Patterns of variation, within and among populations, are similar to those observed for other autosomal markers (e.g. microsatellites and protein polymorphisms), suggesting that the diversity observed at the CYP2D6 locus reflects the same factors affecting variation at random genome markers.

  13. Parametric nanomechanical amplification at very high frequency.

    Science.gov (United States)

    Karabalin, R B; Feng, X L; Roukes, M L

    2009-09-01

    Parametric resonance and amplification are important in both fundamental physics and technological applications. Here we report very high frequency (VHF) parametric resonators and mechanical-domain amplifiers based on nanoelectromechanical systems (NEMS). Compound mechanical nanostructures patterned by multilayer, top-down nanofabrication are read out by a novel scheme that parametrically modulates longitudinal stress in doubly clamped beam NEMS resonators. Parametric pumping and signal amplification are demonstrated for VHF resonators up to approximately 130 MHz and provide useful enhancement of both resonance signal amplitude and quality factor. We find that Joule heating and reduced thermal conductance in these nanostructures ultimately impose an upper limit to device performance. We develop a theoretical model to account for both the parametric response and nonequilibrium thermal transport in these composite nanostructures. The results closely conform to our experimental observations, elucidate the frequency and threshold-voltage scaling in parametric VHF NEMS resonators and sensors, and establish the ultimate sensitivity limits of this approach.

  14. High frequency image-based flow detection

    Energy Technology Data Exchange (ETDEWEB)

    Chung, R [National Heart and Lung Institute, Royal Brompton Hospital, London SW3 6NP (United Kingdom); Prager, R W [Dept. of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom); Gee, A H [Dept. of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom); Treece, G M [Dept. of Engineering, University of Cambridge, Cambridge CB2 1PZ (United Kingdom)

    2004-01-01

    Tumour angiogenesis refers to neovascular development on a microvascular scale and is an early indicator of cancer. Prototype high frequency pulsed Doppler systems using 50 MHz transducers have been reported to detect microvascular flow in vessels 0.02 mm to 0.5 mm in diameter at superficial depths of 0.5 mm. Detecting flow in microvasculature at deeper depths requires lower frequency transducers with a resulting tradeoff in spatial resolution. Using a 22 MHz transducer, we demonstrate a speckle decorrelation technique to detect in vitro flow in soft tubing of 0.5 mm diameter at a depth of 2 cm. This image-based decorrelation technique is capable of detecting flow in significantly narrower diameters down to 0.125 mm by decreasing the region of interest.

  15. High frequency oscillations and high frequency functional network characteristics in the intraoperative electrocorticogram in epilepsy

    NARCIS (Netherlands)

    Zweiphenning, W. J E M; van 't Klooster, M. A.; van Diessen, E.; van Klink, N. E C; Huiskamp, G. J M; Gebbink, T. A.; Leijten, F. S S; Gosselaar, P. H.; Otte, W. M.; Stam, C. J.; Braun, K. P J; Zijlmans, G. J M

    2016-01-01

    OBJECTIVE: High frequency oscillations (HFOs; > 80 Hz), especially fast ripples (FRs, 250-500 Hz), are novel biomarkers for epileptogenic tissue. The pathophysiology suggests enhanced functional connectivity within FR generating tissue. Our aim was to determine the relation between brain areas

  16. High frequency oscillations and high frequency functional network characteristics in the intraoperative electrocorticogram in epilepsy

    Directory of Open Access Journals (Sweden)

    W.J.E.M. Zweiphenning

    2016-01-01

    Significance: ‘Baseline’ high-frequency network parameters might help intra-operative recognition of epileptogenic tissue without the need for waiting for events. These findings can increase our understanding of the ‘architecture’ of epileptogenic networks and help unravel the pathophysiology of HFOs.

  17. Lack of any association between insertion/deletion (I/D) polymorphisms in the angiotensin-converting enzyme gene and digestive system cancer risk: a meta-analysis.

    Science.gov (United States)

    Liu, Jin-Fei; Xie, Hao-Jun; Cheng, Tian-Ming

    2013-01-01

    To investigate the association between the gene polymorphisms of angiotensin-converting enzyme (ACE) and digestive system cancer risk. A search was performed in Pubmed, Medline, ISI Web of Science and Chinese Biomedical (CBM) databases, covering all studies until Sep 1st, 2013. Statistical analysis was performed by using Revman5.2 and STATA 12.0. A total of 15 case-control studies comprising 2,390 digestive system cancer patients and 9,706 controls were identified. No significant association was found between the I/D polymorphism and digestive cancer risk (OR =0.93, 95%CI = (0.75, 1.16), P =0.53 for DD+DI vs. II). In the subgroup analysis by ethnicity and cancer type, no significant associations were found for the comparison of DD+DI vs. II. Results from other comparative genetic models also indicated a lack of associations between this polymorphism and digestive system cancer risks. This meta-analysis suggested that the ACE D/I polymorphism might not contribute to the risk of digestive system cancer.

  18. QualitySNP: a pipeline for detecting single nucleotide polymorphisms and insertions/deletions in EST data from diploid and polyploid species

    NARCIS (Netherlands)

    Tang, J.; Vosman, B.; Voorrips, R.E.; Linden, van der C.G.; Leunissen, J.A.M.

    2006-01-01

    Background - Single nucleotide polymorphisms (SNPs) are important tools in studying complex genetic traits and genome evolution. Computational strategies for SNP discovery make use of the large number of sequences present in public databases (in most cases as expressed sequence tags (ESTs)) and are

  19. The relationship between angiotensin-converting enzyme (ACE) insertion (I) / deletion (D) polymorphism, serum ACE activity and bone mineral density (BMD) in older Chinese.

    Science.gov (United States)

    Zhang, Ya-Feng; Wang, Hong; Cheng, Qiong; Qin, Ling; Tang, Nelson Ls; Leung, Ping-Chong; Kwok, Timothy Cy

    2017-01-01

    In this study, we set out to investigate the relationship between angiotensin-converting enzyme ( ACE) I/D polymorphism, serum ACE activity and bone mineral density (BMD) in older Chinese. A standardized, structured, face-to-face interview was performed to collect demographic information. BMD was measured using dual-energy X-ray absorptiometry (DXA). I/D genotypes of ACE were determined by polymerase chain reaction (PCR) amplification. Serum ACE activity was determined photometrically by a commercially available kinetic kit. Multiple linear regression analysis was used to examine the relationship between ACE I/D polymorphism, serum ACE activity and BMD. A total of 1567 males and 1760 females were selected for analyzing the relationship between ACE I/D polymorphism and BMD. There was no significant difference in spine BMD, total hip BMD and femur neck BMD among different ACE I/D genotypes both in males and females. A total of 1699 males and 1739 females were selected for analyzing the relationship between serum ACE activity and BMD. There was also no significant difference in spine BMD, total hip BMD and femur neck BMD among different serum ACE activity groups both in males and females. There was no relationship between ACE I/D polymorphism, serum ACE activity and BMD in older Chinese.

  20. Plant Responses to High Frequency Electromagnetic Fields

    Directory of Open Access Journals (Sweden)

    Alain Vian

    2016-01-01

    Full Text Available High frequency nonionizing electromagnetic fields (HF-EMF that are increasingly present in the environment constitute a genuine environmental stimulus able to evoke specific responses in plants that share many similarities with those observed after a stressful treatment. Plants constitute an outstanding model to study such interactions since their architecture (high surface area to volume ratio optimizes their interaction with the environment. In the present review, after identifying the main exposure devices (transverse and gigahertz electromagnetic cells, wave guide, and mode stirred reverberating chamber and general physics laws that govern EMF interactions with plants, we illustrate some of the observed responses after exposure to HF-EMF at the cellular, molecular, and whole plant scale. Indeed, numerous metabolic activities (reactive oxygen species metabolism, α- and β-amylase, Krebs cycle, pentose phosphate pathway, chlorophyll content, terpene emission, etc. are modified, gene expression altered (calmodulin, calcium-dependent protein kinase, and proteinase inhibitor, and growth reduced (stem elongation and dry weight after low power (i.e., nonthermal HF-EMF exposure. These changes occur not only in the tissues directly exposed but also systemically in distant tissues. While the long-term impact of these metabolic changes remains largely unknown, we propose to consider nonionizing HF-EMF radiation as a noninjurious, genuine environmental factor that readily evokes changes in plant metabolism.

  1. Plant Responses to High Frequency Electromagnetic Fields

    Science.gov (United States)

    Vian, Alain; Davies, Eric; Gendraud, Michel; Bonnet, Pierre

    2016-01-01

    High frequency nonionizing electromagnetic fields (HF-EMF) that are increasingly present in the environment constitute a genuine environmental stimulus able to evoke specific responses in plants that share many similarities with those observed after a stressful treatment. Plants constitute an outstanding model to study such interactions since their architecture (high surface area to volume ratio) optimizes their interaction with the environment. In the present review, after identifying the main exposure devices (transverse and gigahertz electromagnetic cells, wave guide, and mode stirred reverberating chamber) and general physics laws that govern EMF interactions with plants, we illustrate some of the observed responses after exposure to HF-EMF at the cellular, molecular, and whole plant scale. Indeed, numerous metabolic activities (reactive oxygen species metabolism, α- and β-amylase, Krebs cycle, pentose phosphate pathway, chlorophyll content, terpene emission, etc.) are modified, gene expression altered (calmodulin, calcium-dependent protein kinase, and proteinase inhibitor), and growth reduced (stem elongation and dry weight) after low power (i.e., nonthermal) HF-EMF exposure. These changes occur not only in the tissues directly exposed but also systemically in distant tissues. While the long-term impact of these metabolic changes remains largely unknown, we propose to consider nonionizing HF-EMF radiation as a noninjurious, genuine environmental factor that readily evokes changes in plant metabolism. PMID:26981524

  2. High Frequency of Mosaicism among Patients with Neurofibromatosis Type 1 (NF1) with Microdeletions Caused by Somatic Recombination of the JJAZ1 Gene

    OpenAIRE

    Kehrer-Sawatzki, H; Kluwe, L; Sandig, C.; Kohn, M.; Wimmer, K.; Krammer, U.; Peyrl, A.; Jenne, D E; Hansmann, I; Mautner, V.-F.

    2004-01-01

    Detailed analyses of 20 patients with sporadic neurofibromatosis type 1 (NF1) microdeletions revealed an unexpected high frequency of somatic mosaicism (8/20 [40%]). This proportion of mosaic deletions is much higher than previously anticipated. Of these deletions, 16 were identified by a screen of unselected patients with NF1. None of the eight patients with mosaic deletions exhibited the mental retardation and facial dysmorphism usually associated with NF1 microdeletions. Our study demonstr...

  3. Independent de novo 22q11.2 deletions in first cousins with DiGeorge/velocardiofacial syndrome.

    Science.gov (United States)

    Saitta, Sulagna C; Harris, Stacy E; McDonald-McGinn, Donna M; Emanuel, Beverly S; Tonnesen, Melissa K; Zackai, Elaine H; Seitz, Suzanne C; Driscoll, Deborah A

    2004-01-30

    Deletions of chromosome 22q11.2 are found in the vast majority of patients with DiGeorge/velocardiofacial syndrome (DGS/VCFS). This most frequent microdeletion syndrome is estimated to occur in 1 in 4,000 live births. The majority of deletions are de novo, with 10% or less inherited from an affected parent. Here, we report two separate families with recurrence of a 22q11.2 deletion in first cousins. In each family, unaffected siblings (brother and sister) had an affected child. Fluorescence in situ hybridization (FISH) studies of the parents of each affected child were normal and hence, relatives were not considered at an increased risk for recurrence in another pregnancy. We used highly polymorphic microsatellite repeat markers from within 22q11.2 to determine the parental origin of each cousin's deletion and to assess whether parental germline mosaicism for the 22q11.2 deletion might be a factor in these cases. This analysis confirmed that in each case, the deletion occurred on a chromosome 22 derived from unrelated parents, consistent with independent de novo deletion events. Thus, we concluded that germline mosaicism as the underlying mechanism for affected cousins in these families was unlikely. Our findings underscore the high frequency with which the 22q11.2 deletion occurs in the general population and demonstrate the important role that PCR-based parental origin determination can have in recurrence risk counselling. Furthermore, relatives of affected individuals may benefit from genetic counselling and consider prenatal testing for the 22q11.2 deletion in future pregnancies, despite a low recurrence risk. Copyright 2003 Wiley-Liss, Inc.

  4. Asynchronous BCI control using high-frequency SSVEP

    National Research Council Canada - National Science Library

    Diez, Pablo F; Mut, Vicente A; Avila Perona, Enrique M; Laciar Leber, Eric

    2011-01-01

    ...) and high frequency (> 30 Hz). SSVEP-based Brain-Computer Interfaces (BCI) are principally focused on the low and medium range of frequencies whereas there are only a few projects in the high-frequency range...

  5. Expressed sequence tags from the laboratory-grown miniature tomato (Lycopersicon esculentum) cultivar Micro-Tom and mining for single nucleotide polymorphisms and insertions/deletions in tomato cultivars.

    Science.gov (United States)

    Yamamoto, Naoki; Tsugane, Taneaki; Watanabe, Manabu; Yano, Kentaro; Maeda, Fumi; Kuwata, Chikara; Torki, Moez; Ban, Yusuke; Nishimura, Shigeo; Shibata, Daisuke

    2005-08-15

    Laboratory-grown miniature tomato (Lycopersicon esculentum) cultivar Micro-Tom has attracted attention as a host for functional genomics research. In this study, we generated 35,824 expressed sequence tags (ESTs) from leaves and fruits of Micro-Tom. The ESTs comprised 10,287 unigenes (5007 contigs and 5280 singletons), including 1858 novel tomato unigenes. Of the 18 unigenes that shared strong homology with tobacco chloroplast genome sequences, one unigene was likely derived from polyadenylated transcripts of the atpH gene. Interestingly, ESTs for vacuolar invertase, pectate lyase and alcohol acyl transferase were underrepresented in the Micro-Tom data set. From all of the ESTs, we mined 2039 candidate single nucleotide polymorphisms (SNPs) and 121 candidate insertions and deletions (indels) based on homology with four tomato inbred lines, E6203, R11-13, Rio Grande PtoR and R11-12, and a wild relative, L. pennellii TA56, for which sequence data was publicly available with more than 5000 entries. Direct genome sequencing of several SNP or indel sites in Micro-Tom and L. esculentum E6203 suggested that more than 69% of the candidate sites were truly polymorphic, making them useful for the preparation of DNA markers.

  6. High frequency oscillations and high frequency functional network characteristics in the intraoperative electrocorticogram in epilepsy.

    Science.gov (United States)

    Zweiphenning, W J E M; van 't Klooster, M A; van Diessen, E; van Klink, N E C; Huiskamp, G J M; Gebbink, T A; Leijten, F S S; Gosselaar, P H; Otte, W M; Stam, C J; Braun, K P J; Zijlmans, G J M

    2016-01-01

    High frequency oscillations (HFOs; > 80 Hz), especially fast ripples (FRs, 250-500 Hz), are novel biomarkers for epileptogenic tissue. The pathophysiology suggests enhanced functional connectivity within FR generating tissue. Our aim was to determine the relation between brain areas showing FRs and 'baseline' functional connectivity within EEG networks, especially in the high frequency bands. We marked FRs, ripples (80-250 Hz) and spikes in the electrocorticogram of 14 patients with refractory temporal lobe epilepsy. We assessed 'baseline' functional connectivity in epochs free of epileptiform events within these recordings, using the phase lag index. We computed the Eigenvector Centrality (EC) per channel in the FR and gamma band network. We compared EC between channels that did or did not show events at other moments in time. FR-band EC was higher in channels with than without spikes. Gamma-band EC was lower in channels with ripples and FRs. We confirmed previous findings of functional isolation in the gamma-band and found a first proof of functional integration in the FR-band network of channels covering presumed epileptogenic tissue. 'Baseline' high-frequency network parameters might help intra-operative recognition of epileptogenic tissue without the need for waiting for events. These findings can increase our understanding of the 'architecture' of epileptogenic networks and help unravel the pathophysiology of HFOs.

  7. Association between the SERPINE1 (PAI-1) 4G/5G insertion/deletion promoter polymorphism (rs1799889) and pre-eclampsia: a systematic review and meta-analysis.

    Science.gov (United States)

    Zhao, Linlu; Bracken, Michael B; Dewan, Andrew T; Chen, Suzan

    2013-03-01

    The SERPINE1 -675 4G/5G promoter region insertion/deletion polymorphism (rs1799889) has been implicated in the pathogenesis of pre-eclampsia (PE), but the genetic association has been inconsistently replicated. To derive a more precise estimate of the association, a systematic review and meta-analysis was conducted. This study conformed to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed (MEDLINE), Scopus and HuGE Literature Finder literature databases were systematically searched for relevant studies. Summary odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for the allelic comparison (4G versus 5G) and genotypic comparisons following the co-dominant (4G/4G versus 5G/5G and 4G/5G versus 5G/5G), dominant (4G/4G+4G/5G versus 5G/5G) and recessive (4G/4G versus 4G/5G+5G/5G) genetic models. Between-study heterogeneity was quantified by I(2) statistics and publication bias was appraised with funnel plots. Sensitivity analysis was conducted to evaluate the robustness of meta-analysis findings. Meta-analysis of 11 studies involving 1297 PE cases and 1791 controls found a significant association between the SERPINE1 -675 4G/5G polymorphism and PE for the recessive genetic model (OR = 1.36, 95% CI: 1.13-1.64, P = 0.001), a robust finding according to sensitivity analysis. A low level of between-study heterogeneity was detected (I(2) = 20%) in this comparison, which may be explained by ethnic differences. Funnel plot inspection did not reveal evidence of publication bias. In conclusion, this study provides a comprehensive examination of the available literature on the association between SERPINE1 -675 4G/5G and PE. Meta-analysis results support this polymorphism as a likely susceptibility variant for PE.

  8. The Dominant white, Dun and Smoky Color Variants in Chicken Are Associated With Insertion/Deletion Polymorphisms in the PMEL17 Gene

    Science.gov (United States)

    Kerje, Susanne; Sharma, Preety; Gunnarsson, Ulrika; Kim, Hyun; Bagchi, Sonchita; Fredriksson, Robert; Schütz, Karin; Jensen, Per; von Heijne, Gunnar; Okimoto, Ron; Andersson, Leif

    2004-01-01

    Dominant white, Dun, and Smoky are alleles at the Dominant white locus, which is one of the major loci affecting plumage color in the domestic chicken. Both Dominant white and Dun inhibit the expression of black eumelanin. Smoky arose in a White Leghorn homozygous for Dominant white and partially restores pigmentation. PMEL17 encodes a melanocyte-specific protein and was identified as a positional candidate gene due to its role in the development of eumelanosomes. Linkage analysis of PMEL17 and Dominant white using a red jungle fowl/White Leghorn intercross revealed no recombination between these loci. Sequence analysis showed that the Dominant white allele was exclusively associated with a 9-bp insertion in exon 10, leading to an insertion of three amino acids in the PMEL17 transmembrane region. Similarly, a deletion of five amino acids in the transmembrane region occurs in the protein encoded by Dun. The Smoky allele shared the 9-bp insertion in exon 10 with Dominant white, as expected from its origin, but also had a deletion of 12 nucleotides in exon 6, eliminating four amino acids from the mature protein. These mutations are, together with the recessive silver mutation in the mouse, the only PMEL17 mutations with phenotypic effects that have been described so far in any species. PMID:15579702

  9. A study of the possible association of plasminogen activator inhibitor type 1 4G/5G insertion/deletion polymorphism with susceptibility to schizophrenia and in its subtypes.

    Science.gov (United States)

    Yenilmez, C; Ozdemir Koroglu, Z; Kurt, H; Yanas, M; Colak, E; Degirmenci, I; Gunes, H V

    2017-02-01

    Inhibition of the fibrinolytic system may occur at the level of plasminogen activation, mainly by PAI-1. Mental and physical stress caused to alterations of platelet function, and also decreased to fibrinolytic activity. Furthermore, stress-induced thrombosis regulation was proposed to be by PAI-1 in schizophrenia patients. In this study, the distribution of genotypes and frequency of alleles of the plasminogen activator inhibitor type 1 (PAI-1) gene 4G/5G polymorphism in different Turkish clinical schizophrenia subtypes was investigated for its role in schizophrenia development. The clinical schizophrenia subtypes include paranoid, catatonic, disorganized, undifferentiated and residual, as diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition IV (DSM-IV). Samples of genomic DNA (250 total, including 150 schizophrenia patients and 100 healthy subjects) were analysed. PAI-1 4G/5G genotyping was performed by polymerase chain reaction-allele-specific amplification. PCR products were separated by 2% agarose gel electrophoresis and then visualized. The genotype distributions (P = 0·136) and allele frequencies (P = 0·721 for 4G, P = 0. 097 for 5G) were not significantly different between patients with schizophrenia and control subjects for the 4G/5G polymorphism. Similar results were also found for the genotype distributions (P = 0·640) and allele frequencies (P = 0·763 for 4G, P = 0·448 for 5G) in the clinical schizophrenia subtypes compared to the each other. We conclude that PAI-1 4G/5G polymorphism was not significantly associated with schizophrenia or its subtypes in the Turkish population. However, we recognize that with our sample sizes, we cannot exclude weak associations. © 2016 John Wiley & Sons Ltd.

  10. High frequency of BTG1 deletions in acute lymphoblastic leukemia in children with down syndrome

    DEFF Research Database (Denmark)

    Lundin, Catarina; Hjorth, Lars; Behrendtz, Mikael

    2012-01-01

    Previous cytogenetic studies of myeloid and acute lymphoblastic leukemias in children with Down syndrome (ML-DS and DS-ALL) have revealed significant differences in abnormality patterns between such cases and acute leukemias in general. Also, certain molecular genetic aberrations characterize DS...

  11. Gender difference of serum angiotensin-converting enzyme (ACE) activity in DD genotype of ACE insertion/deletion polymorphism in elderly Chinese.

    Science.gov (United States)

    Zhang, Ya-Feng; Cheng, Qiong; Tang, Nelson L S; Chu, Tanya T W; Tomlinson, Brian; Liu, Fan; Kwok, Timothy C Y

    2014-12-01

    In this study we investigated the gender difference of serum angiotensin-converting enzyme (ACE) activity in a population of Hong Kong-dwelling elderly Chinese. A total of 1767 (843 male, 924 female) Hong Kong-dwelling elderly Chinese were recruited. ACE I/D genotypes were identified by polymerase chain reaction amplification and serum ACE activity was determined using a commercially available kinetic kit. ACE I/D genotype distribution was compared by chi-square test, the correlation between ACE I/D polymorphism and serum ACE activity was analysed by ANOVA test and gender difference of serum ACE activity of different genotypes was compared by independent sample t-test. No statistically significant difference of genotype distribution between male and female subjects was found. Serum ACE activity was significantly correlated with ACE genotype. Overall, there was no gender difference of serum ACE activity; however, when sub-grouping the subjects by ACE I/D genotype, male subjects with DD genotype had higher serum ACE activity than female subjects with DD genotype. No significant gender difference of genotype distribution was found in elderly Chinese. Serum ACE activity was significantly correlated with ACE I/D polymorphism in elderly Chinese. Male subjects with DD genotype had higher serum ACE activity than female subjects with DD genotype. © The Author(s) 2013.

  12. Prognostic value of the insertion/deletion polymorphism of the ACE gene in type 2 diabetic subjects: results from the Non-insulin-dependent Diabetes, Hypertension, Microalbuminuria or Proteinuria, Cardiovascular Events, and Ramipril (DIABHYCAR), Diabete de type 2, Nephropathie et Genetique (DIAB2NEPHROGENE), and Survie, Diabete de type 2 et Genetique (SURDIAGENE) studies.

    Science.gov (United States)

    Hadjadj, Samy; Fumeron, Frédéric; Roussel, Ronan; Saulnier, Pierre-Jean; Gallois, Yves; Ankotche, Amos; Travert, Florence; Abi Khalil, Charbel; Miot, Aurélie; Alhenc-Gelas, François; Lievre, Michel; Marre, Michel

    2008-09-01

    We tested whether determination of the ACE insertion/deletion polymorphism is useful for renal and cardiovascular prognoses of type 2 diabetic subjects. The French participants (3,126 of 4,912) in the Non-Insulin-Dependent Diabetes, Hypertension, Microalbuminuria or Proteinuria, Cardiovascular Events, and Ramipril (DIABHYCAR) trial were studied for their prognosis over 4 years according to their ACE insertion/deletion polymorphism. We used two cohorts of French type 2 diabetic patients for replication: a 3-year follow-up study (n = 917; Survie, Diabete de type 2 et Genetique [SURDIAGENE] study) and a case-control study on diabetic nephropathy (n = 1,277; Diabete de type 2, Nephropathie et Genetique [DIAB2NEPHROGENE] study). We investigated the effect of the insertion/deletion polymorphism on the primary outcome in the DIABHYCAR trial (defined as the first of the following events to occur: cardiovascular death, nonfatal myocardial infarction, stroke, heart failure leading to hospital admission, or end-stage renal failure) and its components. In DIABHYCAR, the primary outcome and most of its components were not affected by the ACE insertion/deletion genotype. Only renal outcome was favored by the I allele (P = 0.03). The risk of myocardial infarction was not affected by ACE genotype, but the probability of fatal outcome increased with the number of D alleles (P < 0.03). In SURDIAGENE, the association between the ACE I allele and renal outcome was not replicated. In DIAB2NEPHROGENE, no association was found with nephropathy. We were not able to demonstrate the manifest usefulness of the ACE insertion/deletion polymorphism for the prognosis of type 2 diabetic subjects.

  13. High-Frequency Variation of Purine Biosynthesis Genes Is a Mechanism of Success in Campylobacter jejuni.

    Science.gov (United States)

    Cameron, Andrew; Huynh, Steven; Scott, Nichollas E; Frirdich, Emilisa; Apel, Dmitry; Foster, Leonard J; Parker, Craig T; Gaynor, Erin C

    2015-09-29

    Phenotypic variation is prevalent in the zoonotic pathogen Campylobacter jejuni, the leading agent of enterocolitis in the developed world. Heterogeneity enhances the survival and adaptive malleability of bacterial populations because variable phenotypes may allow some cells to be protected against future stress. Exposure to hyperosmotic stress previously revealed prevalent differences in growth between C. jejuni strain 81-176 colonies due to resistant or sensitive phenotypes, and these isolated colonies continued to produce progeny with differential phenotypes. In this study, whole-genome sequencing of isolated colonies identified allelic variants of two purine biosynthesis genes, purF and apt, encoding phosphoribosyltransferases that utilize a shared substrate. Genetic analyses determined that purF was essential for fitness, while apt was critical. Traditional and high-depth amplicon-sequencing analyses confirmed extensive intrapopulation genetic variation of purF and apt that resulted in viable strains bearing alleles with in-frame insertion duplications, deletions, or missense polymorphisms. Different purF and apt alleles were associated with various stress survival capabilities under several niche-relevant conditions and contributed to differential intracellular survival in an epithelial cell infection model. Amplicon sequencing revealed that intracellular survival selected for stress-fit purF and apt alleles, as did exposure to oxygen and hyperosmotic stress. Putative protein recognition direct repeat sequences were identified in purF and apt, and a DNA-protein affinity screen captured a predicted exonuclease that promoted the global spontaneous mutation rate. This work illustrates the adaptive properties of high-frequency genetic variation in two housekeeping genes, which influences C. jejuni survival under stress and promotes its success as a pathogen. C. jejuni is an important cause of bacterial diarrheal illness. Bacterial populations have many

  14. Effect of ACE insertion/deletion and 12 other polymorphisms on clinical outcomes and response to treatment in the life study

    DEFF Research Database (Denmark)

    2010-01-01

    OBJECTIVE: This pharmacogenetics substudy from the Losartan Intervention for Endpoint reduction in Hypertension study in patients with hypertension and left ventricular hypertrophy (LVH) treated with the angiotensin receptor blocker losartan versus the beta-blocker atenolol for 4.8 years tested....... These polymorphisms were chosen because they could affect blood pressure control or the pharmacological action of losartan or atenolol. METHODS: We genotyped 3503 patients, 1774 on losartan and 1729 on atenolol. RESULTS: ACE and the 12 other genotypes did not affect the reduction in systolic blood pressure, diastolic...... blood pressure, pulse pressure, mean arterial pressure, or heart rate, or treatment differences between losartan and atenolol on these endpoints, as assessed by general linear models. Also, ACE and the 12 other genotypes did not affect risk of the primary composite endpoint or its components stroke...

  15. Multifunctional Magnetodielectric Composites for Antenna and High Frequency Applications

    National Research Council Canada - National Science Library

    Zhang, Xiaokai; Golt, Michael C; Ekiert, Jr., Thomas F; Yarlagadda, Shridhar; Unruh, Karl M; Xaio, John Q

    2006-01-01

    Miniaturization of high frequency antennas while maintaining desirable bandwidth, impedance, and loss characteristics has recently attracted great attention in part due to the development of metamaterials...

  16. Genetic variation and forensic efficiency of autosomal insertion/deletion polymorphisms in Chinese Bai ethnic group: phylogenetic analysis to other populations

    Science.gov (United States)

    Yang, Chun-Hua; Yin, Cai-Yong; Shen, Chun-Mei; Guo, Yu-Xin; Dong, Qian; Yan, Jiang-Wei; Wang, Hong-Dan; Zhang, Yu-Dang; Meng, Hao-Tian; Jin, Rui

    2017-01-01

    Thirty insertion/deletion loci were utilized to study the genetic diversities of 125 bloodstain samples collected from Bai group in Yunnan Dali region, China. The observed heterozygosity and expected heterozygosity of the 30 loci ranged from 0.1520 to 0.5680, and 0.1927 to 0.4997, respectively. No deviations from Hardy-Weinberg equilibrium tests after Bonferroni correction were found at all 30 loci in Bai group. The cumulative probability of exclusion and combined discrimination power were 0.9859 and 0.9999999999887, respectively, which indicated the 30 loci could be used as complementary genetic markers for paternity testing and were qualified for personal identification in forensic cases. We found the studied Bai group had close relationships with Tibetan, Yi and Han groups from China by the population structure, principal component analysis, population differentiations, and phylogenetic reconstruction studies. Even so, for a better understanding of Bai ethnicity's genetic milieu, DNA genotyping at various genetic markers is necessary in future studies. PMID:28465476

  17. The exon3-deleted growth hormone receptor gene polymorphism (d3-GHR) is associated with insulin and spontaneous growth in short SGA children (NESGAS).

    Science.gov (United States)

    Wegmann, Mathilde Gersel; Thankamony, Ajay; Roche, Edna; Hoey, Hilary; Kirk, Jeremy; Shaikh, Guftar; Ivarsson, Sten-A; Söder, Olle; Dunger, David B; Juul, Anders; Jensen, Rikke Beck

    2017-08-01

    The effect of a common polymorphism in the Growth Hormone (GH) receptor (d3-GHR) gene on growth, metabolism and body composition was examined in short children born small for gestational age (SGA) on GH treatment. In 96 prepubertal, short SGA children treated with high-dose GH (67μg/kg/day) in the NESGAS study, insulin sensitivity (IS), insulin secretion and disposition index (DI) were determined during the first year of treatment. Body composition was analysed by DXA. The d3-GHR locus was determined by simple multiplex PCR. At baseline, children in the d3-GHR group (d3/fl (n=37), d3/d3 (n=7)) had significantly lower IS (median (25-75 percentile)) (223.3% (154.4-304.8)) vs. (269.7% (185.1-356.7)) (p=0.03) and higher concentrations of glucose (mean (SD)) (4.4mmol/L (0.6) vs. 4.2mmol/L (0.7)) (p=0.03), C-peptide (232.1pmol/L (168.8-304.1) vs. 185.1pmol/L (137.7-253.9)) (p=0.04) and insulin (19.2pmol/L (11.8-32.2)) vs. (13.7pmol/L (9.3-20.8)) (p=0.04) compared to children homozygous for the full length allele (fl/fl-GHR (n=52)). There were no differences in DI or insulin secretion. Postnatal, spontaneous growth was significantly greater in the d3-GHR group compared to the fl/fl-GHR group (p=0.02). There were no significant differences in growth response, body composition or metabolism after one year of GH therapy. Short SGA children carrying the d3-GHR polymorphism had increased spontaneous growth, lower IS and a compensatory increase in glucose, C-peptide and insulin before GH therapy compared to children homozygous for the full-length allele. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. A forward-backward fragment assembling algorithm for the identification of genomic amplification and deletion breakpoints using high-density single nucleotide polymorphism (SNP array

    Directory of Open Access Journals (Sweden)

    Bailey Dione K

    2007-05-01

    Full Text Available Abstract Background DNA copy number aberration (CNA is one of the key characteristics of cancer cells. Recent studies demonstrated the feasibility of utilizing high density single nucleotide polymorphism (SNP genotyping arrays to detect CNA. Compared with the two-color array-based comparative genomic hybridization (array-CGH, the SNP arrays offer much higher probe density and lower signal-to-noise ratio at the single SNP level. To accurately identify small segments of CNA from SNP array data, segmentation methods that are sensitive to CNA while resistant to noise are required. Results We have developed a highly sensitive algorithm for the edge detection of copy number data which is especially suitable for the SNP array-based copy number data. The method consists of an over-sensitive edge-detection step and a test-based forward-backward edge selection step. Conclusion Using simulations constructed from real experimental data, the method shows high sensitivity and specificity in detecting small copy number changes in focused regions. The method is implemented in an R package FASeg, which includes data processing and visualization utilities, as well as libraries for processing Affymetrix SNP array data.

  19. Calculation of Leakage Inductance for High Frequency Transformers

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Jun, Zhang; Hurley, William Gerard

    2015-01-01

    Frequency dependent leakage inductance is often observed. High frequency eddy current effects cause a reduction in leakage inductance. The proximity effect between adjacent layers is responsible for the reduction of leakage inductance. This paper gives a detailed analysis of high frequency leakage...

  20. High frequency plant regeneration from desiccated calli of indica rice

    African Journals Online (AJOL)

    An efficient and reproducible protocol is required to achieve high frequency transformation from transformed calli. We report here high frequency plant regeneration from mature seed derived embryogenic calli of two recalcitrant indica rice cultivars HKR-46 and HKR-126 after partial desiccation treatment. Embryogenic and ...

  1. ACE insertion/deletion polymorphism (rs1799752) modifies the renoprotective effect of renin-angiotensin system blockade in patients with IgA nephropathy.

    Science.gov (United States)

    Teranishi, Junya; Yamamoto, Ryohei; Nagasawa, Yasuyuki; Shoji, Tatsuya; Iwatani, Hirotsugu; Okada, Noriyuki; Moriyama, Toshiki; Yamauchi, Atsushi; Tsubakihara, Yoshiharu; Imai, Enyu; Rakugi, Hiromi; Isaka, Yoshitaka

    2015-09-01

    Little is known about genetic predictors that modify the renoprotective effect of renin-angiotensin system (RAS) blockade in IgA nephropathy (IgAN). The present multicenter retrospective observational study examined effect modification between RAS blockade and three RAS-related gene polymorphisms in 237 IgAN patients, including ACE I/D (rs1799752), AT1R A1166C (rs5186) and AGT T704C (rs699). During 9.9 ± 4.2 years of observation, 63 patients progressed to a 50% increase in serum creatinine level. Only ACE I/D predicted the outcome (ACE DD vs ID/II, hazard ratio 1.86 (95% confidence interval 1.03, 3.33)) and modified the renoprotective effect of RAS blockade (p for interaction between ACE DD and RAS blockade = 0.087). RAS blockade suppressed progression in ACE DD patients but not in ID/II patients (ACE ID/II with RAS blockade as a reference; ID/II without RAS blockade 1.45 (0.72, 2.92); DD without RAS blockade 3.06 (1.39, 6.73); DD with RAS blockade 1.51 (0.54, 4.19)), which was ascertained in a model with the outcome of slope of estimated glomerular filtration rate (p = 0.045 for interaction). ACE I/D predicted the IgAN progression and the renoprotective effect of RAS blockade in IgAN patients whereas neither AT1R A1166C nor AGT T704C did. © The Author(s) 2014.

  2. Extended high frequency audiometry in users of personal listening devices.

    Science.gov (United States)

    Kumar, Poornima; Upadhyay, Prabhakar; Kumar, Ashok; Kumar, Sunil; Singh, Gautam Bir

    Noise exposure leads to high frequency hearing loss. Use of Personal Listening Devices may lead to decline in high frequency hearing sensitivity because of prolonged exposure to these devices at high volume. This study explores the changes in hearing thresholds by Extended High Frequency audiometry in users of personal listening devices. A descriptive, hospital based observational study was performed with total 100 subjects in age group of 15-30years. Subjects were divided in two groups consisting of 30 subjects (Group A) with no history of Personal Listening Devices use and (Group B) having 70 subjects with history of use of Personal Listening Devices. Conventional pure tone audiometry with extended high frequency audiometry was performed in all the subjects. Significant differences in hearing thresholds of Personal Listening Device users were seen at high frequencies (3kHz, 4kHz and 6kHz) and extended high frequencies (9kHz, 10kHz, 11kHz, 13kHz, 14kHz, 15kHz and 16kHz) with p value 5years usage at high volume. Thus, it can be reasonably concluded that extended high frequencies can be used for early detection of NIHL in PLD users. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. High-frequency energy in singing and speech

    Science.gov (United States)

    Monson, Brian Bruce

    While human speech and the human voice generate acoustical energy up to (and beyond) 20 kHz, the energy above approximately 5 kHz has been largely neglected. Evidence is accruing that this high-frequency energy contains perceptual information relevant to speech and voice, including percepts of quality, localization, and intelligibility. The present research was an initial step in the long-range goal of characterizing high-frequency energy in singing voice and speech, with particular regard for its perceptual role and its potential for modification during voice and speech production. In this study, a database of high-fidelity recordings of talkers was created and used for a broad acoustical analysis and general characterization of high-frequency energy, as well as specific characterization of phoneme category, voice and speech intensity level, and mode of production (speech versus singing) by high-frequency energy content. Directionality of radiation of high-frequency energy from the mouth was also examined. The recordings were used for perceptual experiments wherein listeners were asked to discriminate between speech and voice samples that differed only in high-frequency energy content. Listeners were also subjected to gender discrimination tasks, mode-of-production discrimination tasks, and transcription tasks with samples of speech and singing that contained only high-frequency content. The combination of these experiments has revealed that (1) human listeners are able to detect very subtle level changes in high-frequency energy, and (2) human listeners are able to extract significant perceptual information from high-frequency energy.

  4. Low frequency phase signal measurement with high frequency squeezing

    OpenAIRE

    Zhai, Zehui; Gao, Jiangrui

    2011-01-01

    We calculate the utility of high-frequency squeezed-state enhanced two-frequency interferometry for low-frequency phase measurement. To use the high-frequency sidebands of the squeezed light, a two-frequency intense laser is used in the interferometry instead of a single-frequency laser as usual. We find that the readout signal can be contaminated by the high-frequency phase vibration, but this is easy to check and avoid. A proof-of-principle experiment is in the reach of modern quantum optic...

  5. An inkjet vision measurement technique for high-frequency jetting

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Kye-Si, E-mail: kskwon@sch.ac.kr; Jang, Min-Hyuck; Park, Ha Yeong [Department of Mechanical Engineering, Soonchunhyang University 22, Soonchunhyang-Ro, Shinchang, Asan Chungnam 336-745 (Korea, Republic of); Ko, Hyun-Seok [Department of Electrical and Robot Engineering, Soonchunhyang University, 22, Soonchunhyang-Ro, Shinchang, Asan Chungnam 336-745 (Korea, Republic of)

    2014-06-15

    Inkjet technology has been used as manufacturing a tool for printed electronics. To increase the productivity, the jetting frequency needs to be increased. When using high-frequency jetting, the printed pattern quality could be non-uniform since the jetting performance characteristics including the jetting speed and droplet volume could vary significantly with increases in jet frequency. Therefore, high-frequency jetting behavior must be evaluated properly for improvement. However, it is difficult to measure high-frequency jetting behavior using previous vision analysis methods, because subsequent droplets are close or even merged. In this paper, we present vision measurement techniques to evaluate the drop formation of high-frequency jetting. The proposed method is based on tracking target droplets such that subsequent droplets can be excluded in the image analysis by focusing on the target droplet. Finally, a frequency sweeping method for jetting speed and droplet volume is presented to understand the overall jetting frequency effects on jetting performance.

  6. Instrumentation for high-frequency meteorological observations from research vessel

    Digital Repository Service at National Institute of Oceanography (India)

    VijayKumar, K.; Khalap, S.; Mehra, P.

    Ship provides an attractive platform from which high-frequency meteorological observations (e.g., wind components, water vapor density, and air temperature) can be made accurately. However, accurate observations of meteorological variables depend...

  7. Music students: conventional hearing thresholds and at high frequencies

    National Research Council Canada - National Science Library

    Lüders, Débora; Gonçalves, Cláudia Giglio de Oliveira; Lacerda, Adriana Bender de Moreira; Ribas, Ângela; Conto, Juliana de

    2014-01-01

    .... To analyze the hearing thresholds from 250 Hz to 16,000 Hz in a group of music students and compare them to a non-musician group in order to determine whether high-frequency audiometry is a useful...

  8. BIOLOGICAL EFFECTS OF HIGH-FREQUENCY ELECTROMAGNETIC WAVES

    Science.gov (United States)

    In this report the author discusses the influence of high-frequency electromagnetic waves on living matter, especially in the field of microwaves. He...of electromagnetic waves . Symptoms of damage are listed and methods of protection discussed.

  9. High-frequency matrix converter with square wave input

    Science.gov (United States)

    Carr, Joseph Alexander; Balda, Juan Carlos

    2015-03-31

    A device for producing an alternating current output voltage from a high-frequency, square-wave input voltage comprising, high-frequency, square-wave input a matrix converter and a control system. The matrix converter comprises a plurality of electrical switches. The high-frequency input and the matrix converter are electrically connected to each other. The control system is connected to each switch of the matrix converter. The control system is electrically connected to the input of the matrix converter. The control system is configured to operate each electrical switch of the matrix converter converting a high-frequency, square-wave input voltage across the first input port of the matrix converter and the second input port of the matrix converter to an alternating current output voltage at the output of the matrix converter.

  10. High-Frequency Microwave Processing of Materials Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Conducts research on high-frequency microwave processing of materials using a highpower, continuous-wave (CW), 83-GHz, quasi-optical beam system for rapid,...

  11. High Temperature, High Frequency Fuel Metering Valve Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Active Signal Technologies and its subcontractor Moog propose to develop a high-frequency actuator driven valve intended to achieve TRL 6 by the end of Phase II....

  12. Music students: conventional hearing thresholds and at high frequencies

    OpenAIRE

    Lüders,Débora; Gonçalves, Cláudia Giglio de Oliveira; de Moreira Lacerda, Adriana Bender; Ribas,Ângela; Conto,Juliana de

    2014-01-01

    INTRODUCTION: Research has shown that hearing loss in musicians may cause difficulty in timbre recognition and tuning of instruments. AIM: To analyze the hearing thresholds from 250 Hz to 16,000 Hz in a group of music students and compare them to a non-musician group in order to determine whether high-frequency audiometry is a useful tool in the early detection of hearing impairment. METHODS: Study design was a retrospective observational cohort. Conventional and high-frequency audio...

  13. Efficacy of Conventional and High-Frequency Ventilation at Altitude

    Science.gov (United States)

    1988-12-01

    evacuation; Mechanical ventilation ;--andL If.’jJI t’ 06 I 12 i ~High-Frequency ventilation ’& ~.~.- 19 ABSTRACT (Continue on reverse If neesry and identify by...The inspired gas and the subsequent rate of appearance of these gases in arterial blood were monitored. With conventional mechanical ventilation (CMV...AND HIGH-FREQUENCY VENTILATION AT ALTITUDE INTRODUCTION The logistics of aeromedical evacuation of patients requiring mechanical ventilation is

  14. An Indel Polymorphism in the MtnA 3' Untranslated Region Is Associated with Gene Expression Variation and Local Adaptation in Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Ana Catalán

    2016-04-01

    Full Text Available Insertions and deletions (indels are a major source of genetic variation within species and may result in functional changes to coding or regulatory sequences. In this study we report that an indel polymorphism in the 3' untranslated region (UTR of the metallothionein gene MtnA is associated with gene expression variation in natural populations of Drosophila melanogaster. A derived allele of MtnA with a 49-bp deletion in the 3' UTR segregates at high frequency in populations outside of sub-Saharan Africa. The frequency of the deletion increases with latitude across multiple continents and approaches 100% in northern Europe. Flies with the deletion have more than 4-fold higher MtnA expression than flies with the ancestral sequence. Using reporter gene constructs in transgenic flies, we show that the 3' UTR deletion significantly contributes to the observed expression difference. Population genetic analyses uncovered signatures of a selective sweep in the MtnA region within populations from northern Europe. We also find that the 3' UTR deletion is associated with increased oxidative stress tolerance. These results suggest that the 3' UTR deletion has been a target of selection for its ability to confer increased levels of MtnA expression in northern European populations, likely due to a local adaptive advantage of increased oxidative stress tolerance.

  15. Chromosome 11q13 deletion syndrome

    OpenAIRE

    Kim, Yu-Seon; Kim, Gun-Ha; Byeon, Jung Hye; Eun, So-Hee; Eun, Baik-Lin

    2016-01-01

    Chromosome 11q13 deletion syndrome has been previously reported as either otodental syndrome or oculo-oto-dental syndrome. The otodental syndrome is characterized by dental abnormalities and high-frequency sensorineural hearing loss, and by ocular coloboma in some cases. The underlying genetic defect causing otodental syndrome is a hemizygous microdeletion involving the FGF3 gene on chromosome 11q13.3. Recently, a new form of severe deafness, microtia (small ear) and small teeth, without the ...

  16. Angiotensin Converting Enzyme Insertion/Deletion Gene ...

    African Journals Online (AJOL)

    Erah

    Pharmacotherapy Group,. Faculty of Pharmacy, University of Benin,. Benin City, 300001 Nigeria. All rights reserved. Available online at http://www.tjpr.org. Research Article. Angiotensin Converting Enzyme Insertion/Deletion. Gene Polymorphism: An Observational Study among. Diabetic Hypertensive Subjects in Malaysia.

  17. [The treatment of glottic carcinoma with high-frequency electrotome].

    Science.gov (United States)

    Mao, Huadong; Xie, Hongwu; Wang, Yakang; Liang, Suqing

    2014-02-01

    To investigate the surgery management of glottic carcinoma with high-frequency electrotome. Twenty cases of patients with glottic carcinoma were treated by cordectomy under micro-laryngoscopy with high-frequency electrotome. The 20 patients were followed up from 5 months to 6 years, retained good laryngeal function and structure: 1 case had local recurrences after 6 months, underwent total laryngectomy, and now no recurrence had been found: 19 cases (mild adhesions of vocal cords formed in 2 cases) had no local recurrence nor lymph node metastasis. It is unnecessary to invest in expensive equipment in the cordectomy under micro-laryngoscopy with high frequency electrotome under general anesthesia and the result is satisfactory.

  18. Condenser Microphone Protective Grid Correction for High Frequency Measurements

    Science.gov (United States)

    Lee, Erik; Bennett, Reginald

    2010-01-01

    Use of a protective grid on small diameter microphones can prolong the lifetime of the unit, but the high frequency effects can complicate data interpretation. Analytical methods have been developed to correct for the grid effect at high frequencies. Specifically, the analysis pertains to quantifying the microphone protective grid response characteristics in the acoustic near field of a rocket plume noise source. A frequency response function computation using two microphones will be explained. Experimental and instrumentation setup details will be provided. The resulting frequency response function for a B&K 4944 condenser microphone protective grid will be presented, along with associated uncertainties

  19. A MEMS-based high frequency x-ray chopper

    Energy Technology Data Exchange (ETDEWEB)

    Siria, A; Schwartz, W; Chevrier, J [Institut Neel, CNRS-Universite Joseph Fourier Grenoble, BP 166, F-38042 Grenoble Cedex 9 (France); Dhez, O; Comin, F [ESRF, 6 rue Jules Horowitz, F-38043 Grenoble Cedex 9 (France); Torricelli, G [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)

    2009-04-29

    Time-resolved x-ray experiments require intensity modulation at high frequencies (advanced rotating choppers have nowadays reached the kHz range). We here demonstrate that a silicon microlever oscillating at 13 kHz with nanometric amplitude can be used as a high frequency x-ray chopper. We claim that using micro-and nanoelectromechanical systems (MEMS and NEMS), it will be possible to achieve higher frequencies in excess of hundreds of megahertz. Working at such a frequency can open a wealth of possibilities in chemistry, biology and physics time-resolved experiments.

  20. Testing the efficiency of high-frequency foreign exchange market

    Directory of Open Access Journals (Sweden)

    Václav Mastný

    2004-01-01

    Full Text Available This paper deals with the efficiency of the high-frequency foreign exchange market. The objective of this paper is to investigate whether standard statistical tests give the same results for time series resampled at intervals of 15.30 and 60 min. The data used for the purpose of this paper contain major currency pairs such as EUR/USD, GBP/USD and JPY/USD. The results of statistical tests indicate that the high frequency intervals (15-minute are not random and should not be considered independent. On the other hand, tests with lower frequency rates (30 and 60 min indicate rising randomness of the market.

  1. Oscillations of the Boundary Layer and High-frequency QPOs

    Directory of Open Access Journals (Sweden)

    Blinova A. A.

    2014-01-01

    Full Text Available We observed persistent high-frequency oscillations of the boundary layer near an accreting, weakly-magnetized star in global 3D MHD simulations. The tilted dipole magnetic field is not strong enough to open a gap between the star and the disk. Instead, it forms a highly-wrapped azimuthal field near the surface of the star which slows down rotation of the disk matter, while a small tilt of the field excites oscillations of the boundary layer with a frequency below the Keplerian frequency. This mechanism may be responsible for the high-frequency oscillations in accreting neutron stars, white dwarfs and classical T Tauri stars.

  2. A MEMS-based high frequency x-ray chopper.

    Science.gov (United States)

    Siria, A; Dhez, O; Schwartz, W; Torricelli, G; Comin, F; Chevrier, J

    2009-04-29

    Time-resolved x-ray experiments require intensity modulation at high frequencies (advanced rotating choppers have nowadays reached the kHz range). We here demonstrate that a silicon microlever oscillating at 13 kHz with nanometric amplitude can be used as a high frequency x-ray chopper. We claim that using micro-and nanoelectromechanical systems (MEMS and NEMS), it will be possible to achieve higher frequencies in excess of hundreds of megahertz. Working at such a frequency can open a wealth of possibilities in chemistry, biology and physics time-resolved experiments.

  3. Extracting cardiac myofiber orientations from high frequency ultrasound images

    Science.gov (United States)

    Qin, Xulei; Cong, Zhibin; Jiang, Rong; Shen, Ming; Wagner, Mary B.; Kirshbom, Paul; Fei, Baowei

    2013-03-01

    Cardiac myofiber plays an important role in stress mechanism during heart beating periods. The orientation of myofibers decides the effects of the stress distribution and the whole heart deformation. It is important to image and quantitatively extract these orientations for understanding the cardiac physiological and pathological mechanism and for diagnosis of chronic diseases. Ultrasound has been wildly used in cardiac diagnosis because of its ability of performing dynamic and noninvasive imaging and because of its low cost. An extraction method is proposed to automatically detect the cardiac myofiber orientations from high frequency ultrasound images. First, heart walls containing myofibers are imaged by B-mode high frequency (pig hearts.

  4. Variations in angiotensin-converting enzyme gene insertion/deletion ...

    Indian Academy of Sciences (India)

    Unknown

    The pattern of angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism in the Indian population is poorly known. In order to determine the status of the polymorphism, young unrelated male army recruits were screened. The population had cultural and linguistic differences and lived in an ...

  5. Variations in angiotensin-converting enzyme gene insertion/deletion ...

    Indian Academy of Sciences (India)

    deletion (I/D) polymorphism in the Indian population is poorly known. In order to determine the status of the polymorphism, young unrelated male army recruits were screened. The population had cultural and linguistic differences and lived in an ...

  6. Insertion/deletion gene variants of angiotensin converting enzyme ...

    African Journals Online (AJOL)

    The insertion/deletion (I/D) polymorphism in the angiotensin-converting enzyme gene has been reported to be implicated in the predisposition to essential hypertension (EH). This association may depend on ethnic and genetic backgrounds. The objective of this study was to determine if the possible I/D polymorphism in the ...

  7. Fact or friction: jumps at ultra high frequency

    NARCIS (Netherlands)

    Christensen, K.; Oomen, R.; Podolskij, M.

    2011-01-01

    In this paper, we demonstrate that jumps in financial asset prices are not nearly as common as generally thought, and that they account for only a very small proportion of total return variation. We base our investigation on an extensive set of ultra high-frequency equity and foreign exchange rate

  8. High frequency plant regeneration from shoot tip explants of ...

    African Journals Online (AJOL)

    A high frequency and rapid regeneration protocol was developed from shoot tip explants of Citrullus colocynthis on Murashige and Skoog (MS) medium supplemented with N6-benzylamino-purine (BAP, 0.5 mg/l) and α-naphthalene acetic acid (NAA, 0.5 mg/l). Highest number of shoots (23.0 ± 0.567) was obtained on MS ...

  9. High frequency MOSFET gate drivers technologies and applications

    CERN Document Server

    Zhang, Zhiliang

    2017-01-01

    This book describes high frequency power MOSFET gate driver technologies, including gate drivers for GaN HEMTs, which have great potential in the next generation of switching power converters. Gate drivers serve as a critical role between control and power devices.

  10. Music students: conventional hearing thresholds and at high frequencies

    Directory of Open Access Journals (Sweden)

    Débora Lüders

    2014-07-01

    Full Text Available INTRODUCTION: Research has shown that hearing loss in musicians may cause difficulty in timbre recognition and tuning of instruments. AIM: To analyze the hearing thresholds from 250 Hz to 16,000 Hz in a group of music students and compare them to a non-musician group in order to determine whether high-frequency audiometry is a useful tool in the early detection of hearing impairment. METHODS: Study design was a retrospective observational cohort. Conventional and high-frequency audiometry was performed in 42 music students (Madsen Itera II audiometer and TDH39P headphones for conventional audiometry, and HDA 200 headphones for high-frequency audiometry. RESULTS: Of the 42 students, 38.1% were female students and 61.9% were male students, with a mean age of 26 years. At conventional audiometry, 92.85% had hearing thresholds within normal limits; but even within the normal limits, the worst results were observed in the left ear for all frequencies, except for 4000 Hz; compared to the non-musician group, the worst results occurred at 500 Hz in the left ear, and at 250 Hz, 6000 Hz, 9000 Hz, 10,000 Hz, and 11,200 Hz in both the ears. CONCLUSION: The periodic evaluation of high-frequency thresholds may be useful in the early detection of hearing loss in musicians.

  11. Factors Affecting the Benefits of High-Frequency Amplification

    Science.gov (United States)

    Horwitz, Amy R.; Ahlstrom, Jayne B.; Dubno, Judy R.

    2008-01-01

    Purpose: This study was designed to determine the extent to which high-frequency amplification helped or hindered speech recognition as a function of hearing loss, gain-frequency response, and background noise. Method: Speech recognition was measured monaurally under headphones for nonsense syllables low-pass filtered in one-third-octave steps…

  12. Collocations of High Frequency Noun Keywords in Prescribed Science Textbooks

    Science.gov (United States)

    Menon, Sujatha; Mukundan, Jayakaran

    2012-01-01

    This paper analyses the discourse of science through the study of collocational patterns of high frequency noun keywords in science textbooks used by upper secondary students in Malaysia. Research has shown that one of the areas of difficulty in science discourse concerns lexis, especially that of collocations. This paper describes a corpus-based…

  13. Development and Testing of Adaptive HF (High Frequency) Radio Techniques

    Science.gov (United States)

    1984-10-01

    December 1980). 2. HFDM : AN/USQ-83(XH-1)(V), The High Frequency Digital Modem, Opera- tion and Maintenance Manual, Sylvania Systems Group, Needham Heights...the HF digital modem ( HFDM ) 2 that per- mits implementing of different modulaticn formats simply by changing the program code. The sounding signal can

  14. Music students: conventional hearing thresholds and at high frequencies.

    Science.gov (United States)

    Lüders, Débora; Gonçalves, Cláudia Giglio de Oliveira; Lacerda, Adriana Bender de Moreira; Ribas, Ângela; Conto, Juliana de

    2014-01-01

    Research has shown that hearing loss in musicians may cause difficulty in timbre recognition and tuning of instruments. To analyze the hearing thresholds from 250 Hz to 16,000 Hz in a group of music students and compare them to a non-musician group in order to determine whether high-frequency audiometry is a useful tool in the early detection of hearing impairment. Study design was a retrospective observational cohort. Conventional and high-frequency audiometry was performed in 42 music students (Madsen Itera II audiometer and TDH39P headphones for conventional audiometry, and HDA 200 headphones for high-frequency audiometry). Of the 42 students, 38.1% were female students and 61.9% were male students, with a mean age of 26 years. At conventional audiometry, 92.85% had hearing thresholds within normal limits; but even within the normal limits, the worst results were observed in the left ear for all frequencies, except for 4000 Hz; compared to the non-musician group, the worst results occurred at 500 Hz in the left ear, and at 250 Hz, 6000 Hz, 9000 Hz, 10,000 Hz, and 11,200 Hz in both the ears. The periodic evaluation of high-frequency thresholds may be useful in the early detection of hearing loss in musicians. Copyright © 2014 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  15. Extended high frequency audiometry in polycystic ovary syndrome.

    Science.gov (United States)

    Kucur, Cuneyt; Kucur, Suna Kabil; Gozukara, Ilay; Seven, Ali; Yuksel, Kadriye Beril; Keskin, Nadi; Oghan, Fatih

    2013-01-01

    Polycystic ovarian syndrome (PCOS) is the most common endocrine disorder affecting 5-10% of women in reproductive age. Insulin resistance, dyslipidemia, glucose intolerance, hypertension, and obesity are metabolic disorders accompanying the syndrome. PCOS is a chronic proinflammatory state and the disease is associated with endothelial dysfunction. In diseases with endothelial damage, hearing in high frequencies are mostly effected in early stages. We evaluated extended high frequency hearing loss in PCOS patients. Forty women diagnosed as PCOS and 25 healthy controls were included in this study. Age and BMI of PCOS and control groups were comparable. Each subject was tested with low (250-2000 Hz), high (4000-8000 Hz), and extended high frequency audiometry (8000-20000). Hormonal and biochemical values including LH, LH/FSH, testosterone, fasting glucose, fasting insulin, HOMA-I, and CRP were calculated. PCOS patients showed high levels of LH, LH/FSH, testosterone, fasting insulin, glucose, HOMA-I, and CRP levels. The hearing thresholds of the groups were similar at frequencies of 250, 500, 1000, 2000, and 4000 Hz; statistically significant difference was observed in 8000-14000 Hz in PCOS group compared to control group. PCOS patients have hearing impairment especially in extended high frequencies. Further studies are needed to help elucidate the mechanism behind hearing impairment in association with PCOS.

  16. Modelling financial high frequency data using point processes

    DEFF Research Database (Denmark)

    Hautsch, Nikolaus; Bauwens, Luc

    In this chapter written for a forthcoming Handbook of Financial Time Series to be published by Springer-Verlag, we review the econometric literature on dynamic duration and intensity processes applied to high frequency financial data, which was boosted by the work of Engle and Russell (1997...

  17. High frequency in vitro shoot regeneration of Momordica balsamina ...

    African Journals Online (AJOL)

    A protocol was developed for in vitro propagation by multiple shoot induction of Momordica balsamina (Cucurbitaceae), a climber with high medicinal and nutritional values. High frequencies of multiple shoot regeneration were achieved from auxillary bud of nodal explants. The bud explants were cultured on MS media ...

  18. Automated Screening for High-Frequency Hearing Loss

    NARCIS (Netherlands)

    Vlaming, M.S.M.G.; MacKinnon, R.C.; Jansen, M.; Moore, D.R.

    2014-01-01

    OBJECTIVE: Hearing loss at high frequencies produces perceptual difficulties and is often an early sign of a more general hearing loss. This study reports the development and validation of two new speech-based hearing screening tests in English that focus on detecting hearing loss at frequencies

  19. Current barriers to confine high frequency common mode currents

    NARCIS (Netherlands)

    Moonen, Dominicus Johannes Guilielmus; Buesink, Frederik Johannes Karel; Leferink, Frank Bernardus Johannes

    2016-01-01

    A commercially produced three phase power line filter is submitted to a Current Barrier (CB) Electro-Magnetic Compatibility (EMC) zoning strategy as an attempt to confine high frequency common mode currents. The intent of the paper is not to show how to build a ’perfect’ filter, since this is known.

  20. Practical techniques for enhancing the high-frequency MASW method

    Science.gov (United States)

    For soil exploration in the vadose zone, a high-frequency multi-channel analysis of surface waves (HF-MASW) method has been developed. In the study, several practical techniques were applied to enhance the overtone image of the HF-MASW method. They included (1) the self-adaptive MASW method using a ...

  1. High frequency ultrasound imaging of a single-species biofilm

    NARCIS (Netherlands)

    Shemesh, H.; Goertz, D. E.; van der Sluis, L. W. M.; de Jong, N.; Wu, M. K.; Wesselink, P. R.

    Objective: This study evaluated the feasibility of a high frequency ultrasound scan to examine the 3D morphology of Streptococcus mutans biofilms grown in vitro. Methods: Six 2-day S. mutans biofilms and six 7-day biofilms were grown on tissue culture membranes and on bovine dentine discs. A sterile

  2. Planck 2013 results. VI. High Frequency Instrument data processing

    DEFF Research Database (Denmark)

    Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.

    2013-01-01

    We describe the processing of the 531 billion raw data samples from the High Frequency Instrument (HFI), which we performed to produce six temperature maps from the first 473 days of Planck-HFI survey data. These maps provide an accurate rendition of the sky emission at 100, 143,217, 353, 545...

  3. High-frequency Trading, Algorithmic Finance, and the Flash Crash

    DEFF Research Database (Denmark)

    Borch, Christian

    2016-01-01

    The Flash Crash of 6 May 2010 has an interesting status in discussions of high-frequency trading, i.e. fully automated, superfast computerized trading: it is invoked both as an important illustration of how this field of algorithmic trading operates and, more often, as an example of how fully aut...

  4. Occupational exposure to anaesthetic gases and high-frequency audiometry.

    Science.gov (United States)

    Giorgianni, Concetto; Gangemi, Silvia; Tanzariello, Maria Giuseppina; Barresi, Gaetano; Miceli, Ludovica; D'Arrigo, Graziella; Spatari, Giovanna

    2015-09-01

    Occupational exposure to anaestethic gases has been suggested to induce auditory damages. The aim of this study is to investigate high-frequency audiometric responses in subjects exposed to anaesthetic gases, in order to highlight the possible effects on auditory system. The study was performed on a sample of 30 medical specialists of Messina University Anaesthesia and Intensive care. We have used tonal audiometry as well as high-frequency one. We have compared the responses with those obtained in a similar control group not exposed to anaesthetic gases. Results were compared statistically. Results show a strong correlation (p = 0.000) between left and right ear responses to all the audiometric tests. The exposed and the control group run though the standard audiometry analysis plays different audiometric responses up only to higher frequencies (2000 HZ p = 0.009 and 4000 Hz p = 0.04); in high-frequency audiometry, as all other frequencies, the attention is drew to the fact that the sample groups distinguish themselves in a significantly statistic way (10,000 Hz p = 0.025, 12,000 Hz p = 0.008, 14,000 Hz p = 0.026, 16,000 Hz p = 0.08). The highest values are the ones related to exposed subjects both in standard (2000 Hz p = 0.01, 4000 Hz p = 0.02) and in high-frequency audiometry (10,000 Hz p = 0.011, 12,000 Hz p = 0.004, 14,000 Hz p = 0.012, 16,000 Hz p = 0.004). Results, even if preliminary and referred to a low-range sample, show an involvement of the anatomic structure responsible for the perception of high-frequency audiometric responses in subjects exposed to anaesthetic gases. © The Author(s) 2012.

  5. Automated screening for high-frequency hearing loss.

    Science.gov (United States)

    Vlaming, Marcel S M G; MacKinnon, Robert C; Jansen, Marije; Moore, David R

    2014-01-01

    Hearing loss at high frequencies produces perceptual difficulties and is often an early sign of a more general hearing loss. This study reports the development and validation of two new speech-based hearing screening tests in English that focus on detecting hearing loss at frequencies above 2000 Hz. The Internet-delivered, speech-in noise tests used closed target-word sets of digit triplets or consonant-vowel-consonant (CVC) words presented against a speech-shaped noise masker. The digit triplet test uses the digits 0 to 9 (excluding the disyllabic 7), grouped in quasi-random triplets. The CVC test uses simple words (e.g., "cat") selected for the high-frequency spectral content of the consonants. During testing, triplets or CVC words were identified in an adaptive procedure to obtain the speech reception threshold (SRT) in noise. For these new, high-frequency (HF) tests, the noise was low-pass filtered to produce greater masking of the low-frequency speech components, increasing the sensitivity of the test for HF hearing loss. Individual test tokens (digits, CVCs) were first homogenized using a group of 10 normal-hearing (NH) listeners by equalizing intelligibility across tokens at several speech-in-noise levels. Both tests were then validated and standardized using groups of 24 NH listeners and 50 listeners with hearing impairment. Performance on the new high frequency digit triplet (HF-triplet) and CVC (HF-CVC) tests was compared with audiometric hearing loss, and with that on the unfiltered, broadband digit triplet test (BB-triplet) test, and the ASL (Adaptive Sentence Lists) speech-in-noise test. The HF-triplet and HF-CVC test results (SRT) both correlated positively and highly with high-frequency audiometric hearing loss and with the ASL test. SRT for both tests as a function of high-frequency hearing loss increased at nearly three times the rate as that of the BB-triplet test. The intraindividual variability (SD) on the tests was about 2.1 (HF-triplet) and 1

  6. High Frequency Amplitude Detector for GMI Magnetic Sensors

    Directory of Open Access Journals (Sweden)

    Aktham Asfour

    2014-12-01

    Full Text Available A new concept of a high-frequency amplitude detector and demodulator for Giant-Magneto-Impedance (GMI sensors is presented. This concept combines a half wave rectifier, with outstanding capabilities and high speed, and a feedback approach that ensures the amplitude detection with easily adjustable gain. The developed detector is capable of measuring high-frequency and very low amplitude signals without the use of diode-based active rectifiers or analog multipliers. The performances of this detector are addressed throughout the paper. The full circuitry of the design is given, together with a comprehensive theoretical study of the concept and experimental validation. The detector has been used for the amplitude measurement of both single frequency and pulsed signals and for the demodulation of amplitude-modulated signals. It has also been successfully integrated in a GMI sensor prototype. Magnetic field and electrical current measurements in open- and closed-loop of this sensor have also been conducted.

  7. Extended High Frequency Audiometry in Polycystic Ovary Syndrome

    Directory of Open Access Journals (Sweden)

    Cuneyt Kucur

    2013-01-01

    and BMI of PCOS and control groups were comparable. Each subject was tested with low (250–2000 Hz, high (4000–8000 Hz, and extended high frequency audiometry (8000–20000. Hormonal and biochemical values including LH, LH/FSH, testosterone, fasting glucose, fasting insulin, HOMA-I, and CRP were calculated. Results. PCOS patients showed high levels of LH, LH/FSH, testosterone, fasting insulin, glucose, HOMA-I, and CRP levels. The hearing thresholds of the groups were similar at frequencies of 250, 500, 1000, 2000, and 4000 Hz; statistically significant difference was observed in 8000–14000 Hz in PCOS group compared to control group. Conclusion. PCOS patients have hearing impairment especially in extended high frequencies. Further studies are needed to help elucidate the mechanism behind hearing impairment in association with PCOS.

  8. High-frequency broadband modulation of electroencephalographic spectra

    Directory of Open Access Journals (Sweden)

    Julie A Onton

    2009-12-01

    Full Text Available High-frequency cortical potentials in electroencephalographic (EEG scalp recordings have low amplitudes and may be confounded with scalp muscle activities. EEG data from an eyes-closed emotion imagination task were linearly decomposed using independent component analysis (ICA into maximally independent component (IC processes. Joint decomposition of IC log spectrograms into source- and frequency-independent modulator (IM processes revealed three distinct classes of IMs that separately modulated broadband high-frequency (~15-200 Hz power of brain, scalp muscle, and likely ocular motor IC processes. Multi-dimensional scaling revealed significant but spatially complex relationships between mean broadband brain IM effects and the valence of the imagined emotions. Thus, contrary to prevalent assumption, unitary modes of spectral modulation of frequencies encompassing the beta, gamma, and high gamma frequency ranges can be isolated from scalp-recorded EEG data and may be differentially associated with brain sources and cognitive activities.

  9. High-frequency Oscillations in Eyewalls of Tropical Cyclones

    Science.gov (United States)

    Li, Weibiao; Chen, Shumin

    2017-04-01

    High-frequency oscillations, with periods of about 2 hours, are first identified by applying wavelet analysis to observed minutely wind speeds around the eye and eyewall of tropical cyclones (TCs). Analysis of a model simulation of Typhoon Hagupit (2008) shows that the oscillations also occur in the intensity of TC, vertical motion, convergence activity and air density around the eyewall. Sequences of oscillations in these variables follow a certain order. In a typical cycle, the drop of density in the planetary boundary layer (PBL) is followed by an increase in the inward radial wind; this enhanced frictional convergence causes increase in density, followed by a decrease in the inward radial wind. The increase in convergence in the PBL causes increase of updraft at the top of the PBL, followed by high vertical velocity at high altitude of 8-10 km, then the increase of the maximum wind speed, and vice versa. Key words: tropical cyclone, high-frequency oscillations, eyewall, intensity

  10. High-frequency microrheology reveals cytoskeleton dynamics in living cells

    Science.gov (United States)

    Rigato, Annafrancesca; Miyagi, Atsushi; Scheuring, Simon; Rico, Felix

    2017-08-01

    Living cells are viscoelastic materials, dominated by an elastic response on timescales longer than a millisecond. On shorter timescales, the dynamics of individual cytoskeleton filaments are expected to emerge, but active microrheology measurements on cells accessing this regime are scarce. Here, we develop high-frequency microrheology experiments to probe the viscoelastic response of living cells from 1 Hz to 100 kHz. We report the viscoelasticity of different cell types under cytoskeletal drug treatments. On previously inaccessible short timescales, cells exhibit rich viscoelastic responses that depend on the state of the cytoskeleton. Benign and malignant cancer cells revealed remarkably different scaling laws at high frequencies, providing a unique mechanical fingerprint. Microrheology over a wide dynamic range--up to the frequency characterizing the molecular components--provides a mechanistic understanding of cell mechanics.

  11. Self-integrating inductive loop for measuring high frequency pulses.

    Science.gov (United States)

    Rojas-Moreno, Mónica V; Robles, Guillermo; Martínez-Tarifa, Juan M; Sanz-Feito, Javier

    2011-08-01

    High frequency pulses can be measured by means of inductive sensors. The main advantage of these sensors consists of non-contact measurements that isolate and protect measuring equipment. The objective of this paper is to present the implementation of an inductive sensor for measuring rapidly varying currents. It consists of a rectangular loop with a resistor at its terminals. The inductive loop gives the derivative of the current according to Faraday's law and the resistor connected to the loop modifies the sensor's frequency response to obtain an output proportional to the current pulse. The self-integrating inductive sensor was validated with two sensors, a non-inductive resistor and a commercial high frequency current transformer. The results were compared to determine the advantages and drawbacks of the probe as an adequate inductive transducer.

  12. Unusual Solar Decameter Radio Bursts with High Frequency Cut off

    Science.gov (United States)

    Brazhenko, A. I.; Melnik, V. M.; Frantsuzenko, A. V.; Rucker, H. O.; Panchenko, M.

    2015-03-01

    Solar bursts with high frequency cut off were observed by the URAN-2 radio telescope (Poltava, Ukraine) on 18 August, 2012 in the frequency range 8-32 MHz. Durations of these bursts changed from 30 to 70 s. It is much longer than that for standard type III bursts. Drift rates are much smaller than those of type III bursts are, though much larger than those for decameter type II bursts. In some cases, the drift rate sign changes from the negative to positive one. Some of these bursts have fine structures. Stripes of the fine structures have small drift rates of 20-40 kHz/s. Polarizations of these bursts made about 10 % that apparently indicates that they are generated at the second harmonic of the local plasma frequency. The connection of bursts with the high frequency cut off with compact ejections from the behind-limb active regions is confirmed.

  13. Design of 1 MHz Solid State High Frequency Power Supply

    Science.gov (United States)

    Parmar, Darshan; Singh, N. P.; Gajjar, Sandip; Thakar, Aruna; Patel, Amit; Raval, Bhavin; Dhola, Hitesh; Dave, Rasesh; Upadhay, Dishang; Gupta, Vikrant; Goswami, Niranjan; Mehta, Kush; Baruah, Ujjwal

    2017-04-01

    High Frequency Power supply (HFPS) is used for various applications like AM Transmitters, metallurgical applications, Wireless Power Transfer, RF Ion Sources etc. The Ion Source for a Neutral beam Injector at ITER-India uses inductively coupled power source at High Frequency (∼1 MHz). Switching converter based topology used to generate 1 MHz sinusoidal output is expected to have advantages on efficiency and reliability as compared to traditional RF Tetrode tubes based oscillators. In terms of Power Electronics, thermal and power coupling issues are major challenges at such a high frequency. A conceptual design for a 200 kW, 1 MHz power supply and a prototype design for a 600 W source been done. The prototype design is attempted with Class-E amplifier topology where a MOSFET is switched resonantly. The prototype uses two low power modules and a ferrite combiner to add the voltage and power at the output. Subsequently solution with Class-D H-Bridge configuration have been evaluated through simulation where module design is stable as switching device do not participate in resonance, further switching device voltage rating is substantially reduced. The rating of the modules is essentially driven by the maximum power handling capacity of the MOSFETs and ferrites in the combiner circuit. The output passive network including resonance tuned network and impedance matching network caters for soft switching and matches the load impedance to 50ohm respectively. This paper describes the conceptual design of a 200 kW high frequency power supply and experimental results of the prototype 600 W, 1 MHz source.

  14. High frequency plant regeneration from mature seedderived callus ...

    African Journals Online (AJOL)

    In the present study, we have developed a high-frequency plant regeneration system for Italian ryegrass via callus culture using mature seeds as explants. Optimal embryogenic callus induction was found to occur in MS medium containing 5 mg l-1 2,4-D, 0.5 mg l-1 BA, 500 mg l-1 L-proline, 1 g l-1 casein hydrolysate, 30 g ...

  15. High frequency plant regeneration from mature seed- derived callus ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-15

    Dec 15, 2009 ... In the present study, we have developed a high-frequency plant regeneration system for Italian ryegrass via callus culture using mature seeds as explants. Optimal embryogenic callus induction was found to occur in MS medium containing 5 mg l-1 2,4-D, 0.5 mg l-1 BA, 500 mg l-1 L-proline, 1 g l-1 casein.

  16. DISTRIBUTION OF HIGH-FREQUENCY VOLTAGE IN DISTRIBUTION NETWORK

    Directory of Open Access Journals (Sweden)

    M. I. Polujanov

    2005-01-01

    Full Text Available The paper reveals a method for remote determination of a location of single-phase short circuit on the ground in distribution networks with isolated neutral point. The method is based on measurement of high-frequency (a tone  range inter-phase voltage at all transformer substations and it creates preconditions for automation of searching process.  

  17. Unbalanced heat isolation in high-frequency electrothermics of polymers

    OpenAIRE

    A. V. Livshits

    2014-01-01

    The polymeric materials are widely applied in many industries because they have a number of advantages, which allow their use instead of traditional materials. Nevertheless, the issues of manufacturing products from polymeric materials and their applications are insufficiently studied. The same can be said about high-frequency (HF) electrothermics of polymers. Therefore, mathematical simulation of electrothermic processes is of interest both in terms of science and in terms of applications.Tr...

  18. Automated composite ellipsoid modelling for high frequency GTD analysis

    Science.gov (United States)

    Sze, K. Y.; Rojas, R. G.; Klevenow, F. T.; Scheick, J. T.

    1991-01-01

    The preliminary results of a scheme currently being developed to fit a composite ellipsoid to the fuselage of a helicopter in the vicinity of the antenna location are discussed under the assumption that the antenna is mounted on the fuselage. The parameters of the close-fit composite ellipsoid would then be utilized as inputs into NEWAIR3, a code programmed in FORTRAN 77 for high frequency Geometrical Theory of Diffraction (GTD) Analysis of the radiation of airborne antennas.

  19. A novel high-frequency encoding algorithm for image compression

    Science.gov (United States)

    Siddeq, Mohammed M.; Rodrigues, Marcos A.

    2017-12-01

    In this paper, a new method for image compression is proposed whose quality is demonstrated through accurate 3D reconstruction from 2D images. The method is based on the discrete cosine transform (DCT) together with a high-frequency minimization encoding algorithm at compression stage and a new concurrent binary search algorithm at decompression stage. The proposed compression method consists of five main steps: (1) divide the image into blocks and apply DCT to each block; (2) apply a high-frequency minimization method to the AC-coefficients reducing each block by 2/3 resulting in a minimized array; (3) build a look up table of probability data to enable the recovery of the original high frequencies at decompression stage; (4) apply a delta or differential operator to the list of DC-components; and (5) apply arithmetic encoding to the outputs of steps (2) and (4). At decompression stage, the look up table and the concurrent binary search algorithm are used to reconstruct all high-frequency AC-coefficients while the DC-components are decoded by reversing the arithmetic coding. Finally, the inverse DCT recovers the original image. We tested the technique by compressing and decompressing 2D images including images with structured light patterns for 3D reconstruction. The technique is compared with JPEG and JPEG2000 through 2D and 3D RMSE. Results demonstrate that the proposed compression method is perceptually superior to JPEG with equivalent quality to JPEG2000. Concerning 3D surface reconstruction from images, it is demonstrated that the proposed method is superior to both JPEG and JPEG2000.

  20. Airway Humidification During High-Frequency Percussive Ventilation

    Science.gov (United States)

    2009-03-01

    Association for Respi- ratory Care (AARC) recommendations for the minimum acceptable heating and humidification during mechanical ventilation ( 30°C...Care. AARC clinical practice guideline: humidification during mechanical ventilation . Respir Care 1992;37(8):887-890. 3. Branson RD. The effects of...Airway Humidification During High-Frequency Percussive Ventilation Patrick F Allan MD, Michael J Hollingsworth CRT, Gordon C Maniere CRT, Anthony K

  1. High-Frequency-Trading: Zwischen Nutzeffekten und Risiken

    OpenAIRE

    Gomber, Peter

    2011-01-01

    Die Mehrheit der auf High Frequency Trading basierenden Strategien trägt zur Marktliquidität (Market-Making-Strategien) oder zur Preisfindung und Markteffizienz (Arbitrage-Strategien) bei. Eine ungeeignete Regulierung dieser Strategien oder eine Beeinträchtigung der zugrunde liegenden Geschäftsmodelle durch übermäßige Belastungen kann kontraproduktiv sein und unvorhergesehene Auswirkungen auf die Marktqualität haben. Allerdings muss jede missbräuchliche Strategie effektiv durch die Aufsichtsb...

  2. Probing High Frequency Noise with Macroscopic Resonant Tunneling

    OpenAIRE

    Lanting, T.; Amin, M. H. S.; Johnson, M. W.; Altomare, F.; Berkley, A. J.; Gildert, S.; Harris, R; Johansson, J; Bunyk, P.; Ladizinsky, E.; Tolkacheva, E.; Averin, D. V.

    2011-01-01

    We have developed a method for extracting the high-frequency noise spectral density of an rf-SQUID flux qubit from macroscopic resonant tunneling (MRT) rate measurements. The extracted noise spectral density is consistent with that of an ohmic environment up to frequencies ~ 4 GHz. We have also derived an expression for the MRT lineshape expected for a noise spectral density consisting of such a broadband ohmic component and an additional strongly peaked low-frequency component. This hybrid m...

  3. Asynchronous BCI control using high-frequency SSVEP

    Directory of Open Access Journals (Sweden)

    Laciar Leber Eric

    2011-07-01

    Full Text Available Abstract Background Steady-State Visual Evoked Potential (SSVEP is a visual cortical response evoked by repetitive stimuli with a light source flickering at frequencies above 4 Hz and could be classified into three ranges: low (up to 12 Hz, medium (12-30 and high frequency (> 30 Hz. SSVEP-based Brain-Computer Interfaces (BCI are principally focused on the low and medium range of frequencies whereas there are only a few projects in the high-frequency range. However, they only evaluate the performance of different methods to extract SSVEP. Methods This research proposed a high-frequency SSVEP-based asynchronous BCI in order to control the navigation of a mobile object on the screen through a scenario and to reach its final destination. This could help impaired people to navigate a robotic wheelchair. There were three different scenarios with different difficulty levels (easy, medium and difficult. The signal processing method is based on Fourier transform and three EEG measurement channels. Results The research obtained accuracies ranging in classification from 65% to 100% with Information Transfer Rate varying from 9.4 to 45 bits/min. Conclusions Our proposed method allows all subjects participating in the study to control the mobile object and to reach a final target without prior training.

  4. Occupational hearing loss: tonal audiometry X high frequencies audiometry

    Directory of Open Access Journals (Sweden)

    Lauris, José Roberto Pereira

    2009-09-01

    Full Text Available Introduction: Studies on the occupational exposure show that noise has been reaching a large part of the working population around the world, and NIHL (noise-induced hearing loss is the second most frequent disease of the hearing system. Objective: To review the audiometry results of employees at the campus of the University of São Paulo, Bauru. Method: 40 audiometry results were analyzed between 2007 and 2008, whose ages comprised between 32 and 59 years, of both sexes and several professions: gardeners, maintenance technicians, drivers etc. The participants were divided into 2 groups: those with tonal thresholds within acceptable thresholds and those who presented auditory thresholds alterations, that is tonal thresholds below 25 dB (NA in any frequency (Administrative Rule no. 19 of the Ministry of Labor 1998. In addition to the Conventional Audiologic Evaluation (250Hz to 8.000Hz we also carried out High Frequencies Audiometry (9000Hz, 10000Hz, 11200Hz, 12500Hz, 14000Hz and 16000Hz. Results: According to the classification proposed by FIORINI (1994, 25.0% (N=10 they presented with NIHL suggestive audiometric configurations. The results of high frequencies Audiometry confirmed worse thresholds than those obtained in the conventional audiometry in the 2 groups evaluated. Conclusion: The use of high frequencies audiometry proved to be an important register as a hearing alteration early detection method.

  5. Sustainable limitation of high-frequency oscillations of elevator cabin

    Science.gov (United States)

    Kaytukov, Batraz

    2017-10-01

    In this paper, a problem of sustainable limitation of vertical high-frequency oscillations of elevator cabin in buildings with various number of storeys is considered. To solve this problem, dynamic model of the elevator movement was developed. In the course of analytical and experimental studies, the main cause for emergence of undesirable high-frequency oscillations of a cabin was defined. The amplification factor which is the function of λ and length of cable was determined. The λ parameter is variable, and length of the cable changes depending on length passed by the cabin and is an amplification factor argument. For sustainable limitation of oscillations, use of dynamic dumper of lever type is proposed. Adjustment of the dumper natural vibration frequency in such a way that it is equal to the excitation frequency allows limiting of oscillations of the cabin and the elevator machine to reasonable value irrespective to position of a moving cabin in the shaft. Using dependences and plots which were obtained in the course of scientific analysis and experimental studies, reasonability of dumper application for sustainable limitation of high-frequency influence of the elevator machine on the base and obtaining of solutions of inertial forces equilibration problem was proved.

  6. Phosphorus geochemical cycling inferences from high frequency lake monitoring

    Science.gov (United States)

    Crockford, Lucy; Jordan, Philip; Taylor, David

    2013-04-01

    Freshwater bodies in Europe are required to return to good water quality status under the Water Framework Directive by 2015. A small inter-drumlin lake in the northeast of Ireland has been susceptible to eutrophic episodes and the presence of algal blooms during summer since annual monitoring began in 2002. While agricultural practice has been controlled by the implementation of the Nitrates Directive in 2006, the lake is failing to recover to good water quality status to meet with the Water Framework Directive objectives. Freshwaters in Ireland are regarded, in the main, as phosphorus (P) limited so identifying the sources of P possibly fuelling the algal blooms may provide an insight into how to improve water quality conditions. In a lake, these sources are divided between external catchment driven loads, as a result of farming and point sources, and P released from sediments made available to photic waters through internal lake mechanisms. High frequency sensors on data-sondes, installed on the lake in three locations, have provided chlorophyll a, redox potential, dissolved oxygen, temperature, pH, conductivity and turbidity data since March 2010. A data-sonde was installed in the hypolimnion to observe the change in lake conditions as P is released from lake sediments as a result of geochemical cycling with iron during anoxic periods. As compact high frequency sampling equipment for P analysis is still in its infancy for freshwaters, a proxy measurement of geochemical cycling in lakes would be useful to determine fully the extent of P contribution from sediments to the overall P load. Phosphorus was analysed once per month along with a number of other parameters and initial analysis of the high frequency data has shown changes in readings when known P release from lake sediments has occurred. Importantly, these data have shown when these P enriched hypolimnetic waters may be re-introduced to shallower waters in the photic zone, by changes in dissolved oxygen

  7. Frequency dependence of lung volume changes during superimposed high-frequency jet ventilation and high-frequency jet ventilation.

    Science.gov (United States)

    Sütterlin, R; Priori, R; Larsson, A; LoMauro, A; Frykholm, P; Aliverti, A

    2014-01-01

    Superimposed high-frequency jet ventilation (SHFJV) has proved to be safe and effective in clinical practice. However, it is unclear which frequency range optimizes ventilation and gas exchange. The aim of this study was to systematically compare high-frequency jet ventilation (HFJV) with HFJV by assessing chest wall volume variations (ΔEEV(CW)) and gas exchange in relation to variable high frequency. SHFJV or HFJV were used alternatively to ventilate the lungs of 10 anaesthetized pigs (21-25 kg). The low-frequency component was kept at 16 min(-1) in SHFJV. In both modes, high frequencies ranging from 100 to 1000 min(-1) were applied in random order and ventilation was maintained for 5 min in all modalities. Chest wall volume variations were obtained using opto-electronic plethysmography. Airway pressures and arterial blood gases were measured repeatedly. SHFJV increased ΔEEV(CW) compared with HFJV; the difference ranged from 43 to 68 ml. Tidal volume (V(T)) was always >240 ml during SHFJV whereas during HFJV ranged from 92 ml at the ventilation frequency of 100 min(-1) to negligible values at frequencies >300 min(-1). We observed similar patterns for Pa(O₂) and Pa(CO₂). SHFJV provided generally higher, frequency-independent oxygenation (Pa(O₂) at least 32.0 kPa) and CO₂ removal (Pa(CO₂) ∼5.5 kPa), whereas HFJV led to hypoxia and hypercarbia at higher rates (Pa(O₂) 10 kPa at f(HF)>300 min(-1)). In a porcine model, SHFJV was more effective in increasing end-expiratory volume than single-frequency HFJV, but both modes may provide adequate ventilation in the absence of airway obstruction and respiratory disease, except for HFJV at frequencies ≥300 min(-1).

  8. Association of Angiotensin-Converting Enzyme Intron 16 Insertion/Deletion and Angiotensin II Type 1 Receptor A1166C Gene Polymorphisms with Preeclampsia in South East of Iran

    Directory of Open Access Journals (Sweden)

    Saeedeh Salimi

    2011-01-01

    Full Text Available Some evidence suggests that a variety of genetic factors contributed in pathogenesis of the preeclampsia. The aim of this study was to assess the association between the angiotensin-converting enzyme (ACE I/D and angiotensin II type1 receptor A1166C polymorphisms with preeclampsia. This study was performed in 125 preeclamptic pregnant women and 132 controls. The I/D Polymorphism of the ACE gene was assessed by polymerase chain reaction and the A1166C Polymorphism of the AT1R gene was determined by restriction fragment length polymorphism. The genotype and allele frequencies of I/D polymorphism differed between two groups. The risk of preeclampsia was 3.2-fold in pregnant women with D allele (OR, 3.2 [95% CI, 1.1 to 3.8]; P=0.01. The distribution of the AT1R gene A1166C polymorphism was similar in affected and control groups. Our results supported that presence of the I/D polymorphism of ACE gene is a marker for the increased risk of preeclampsia.

  9. Computation of High-Frequency Waves with Random Uncertainty

    KAUST Repository

    Malenova, Gabriela

    2016-01-06

    We consider the forward propagation of uncertainty in high-frequency waves, described by the second order wave equation with highly oscillatory initial data. The main sources of uncertainty are the wave speed and/or the initial phase and amplitude, described by a finite number of random variables with known joint probability distribution. We propose a stochastic spectral asymptotic method [1] for computing the statistics of uncertain output quantities of interest (QoIs), which are often linear or nonlinear functionals of the wave solution and its spatial/temporal derivatives. The numerical scheme combines two techniques: a high-frequency method based on Gaussian beams [2, 3], a sparse stochastic collocation method [4]. The fast spectral convergence of the proposed method depends crucially on the presence of high stochastic regularity of the QoI independent of the wave frequency. In general, the high-frequency wave solutions to parametric hyperbolic equations are highly oscillatory and non-smooth in both physical and stochastic spaces. Consequently, the stochastic regularity of the QoI, which is a functional of the wave solution, may in principle below and depend on frequency. In the present work, we provide theoretical arguments and numerical evidence that physically motivated QoIs based on local averages of |uE|2 are smooth, with derivatives in the stochastic space uniformly bounded in E, where uE and E denote the highly oscillatory wave solution and the short wavelength, respectively. This observable related regularity makes the proposed approach more efficient than current asymptotic approaches based on Monte Carlo sampling techniques.

  10. Study of switching transients in high frequency converters

    Science.gov (United States)

    Zinger, Donald S.; Elbuluk, Malik E.; Lee, Tony

    1993-01-01

    As the semiconductor technologies progress rapidly, the power densities and switching frequencies of many power devices are improved. With the existing technology, high frequency power systems become possible. Use of such a system is advantageous in many aspects. A high frequency ac source is used as the direct input to an ac/ac pulse-density-modulation (PDM) converter. This converter is a new concept which employs zero voltage switching techniques. However, the development of this converter is still in its infancy stage. There are problems associated with this converter such as a high on-voltage drop, switching transients, and zero-crossing detecting. Considering these problems, the switching speed and power handling capabilities of the MOS-Controlled Thyristor (MCT) makes the device the most promising candidate for this application. A complete insight of component considerations for building an ac/ac PDM converter for a high frequency power system is addressed. A power device review is first presented. The ac/ac PDM converter requires switches that can conduct bi-directional current and block bi-directional voltage. These bi-directional switches can be constructed using existing power devices. Different bi-directional switches for the converter are investigated. Detailed experimental studies of the characteristics of the MCT under hard switching and zero-voltage switching are also presented. One disadvantage of an ac/ac converter is that turn-on and turn-off of the switches has to be completed instantaneously when the ac source is at zero voltage. Otherwise shoot-through current or voltage spikes can occur which can be hazardous to the devices. In order for the devices to switch softly in the safe operating area even under non-ideal cases, a unique snubber circuit is used in each bi-directional switch. Detailed theory and experimental results for circuits using these snubbers are presented. A current regulated ac/ac PDM converter built using MCT's and IGBT's is

  11. Automated Screening for High-Frequency Hearing Loss

    OpenAIRE

    Vlaming, Marcel S M G; Mackinnon, Robert C.; Jansen, Marije; Moore, David R.

    2014-01-01

    OBJECTIVE: Hearing loss at high frequencies produces perceptual difficulties and is often an early sign of a more general hearing loss. This study reports the development and validation of two new speech-based hearing screening tests in English that focus on detecting hearing loss at frequencies above 2000 Hz. DESIGN: The Internet-delivered, speech-in noise tests used closed target-word sets of digit triplets or consonant-vowel-consonant (CVC) words presented against a speech-shaped noise mas...

  12. Very High Frequency Half Bridge DC/DC Converter

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    This paper presents the first, off chip, class DE (resonant half bridge) converter working in the Very High Frequency (VHF) range. The benefits of using half bridge circuits both in the inverter and rectifier part of a VHF resonant dc/dc converter are analyzed and design equations for all...... components in the power stage are given. The circuit has been simulated to verify the accuracy of the presented equations and an efficiency of 89% has been shown. A prototype has been implemented with self-oscillating resonant gate drives driving the switches. The prototype has been used to drive an LED...

  13. High Frequency Modulation Method for Measuring of Birefringence

    Directory of Open Access Journals (Sweden)

    Šulc M.

    2013-05-01

    Full Text Available A method of optical birefringence measurement is presented. It uses an el ectro-optic modulator for the high frequency modulation of polarization of the laser beam. The developed optical apparatus exhibits high sensitivity. It is able to measure very small birefringence of samples down to 10-3 rad. The accuracy and sensitivity of the method was checked by measurement of calibrated Sol eil – Babi net compensator. Method can be also used for online and accurate measurement of an optical components birefringence. This application was developed with the aim to measure Cotton-Mouton effect in air and nitrogen.

  14. Probing high-frequency noise with macroscopic resonant tunneling

    Science.gov (United States)

    Lanting, T.; Amin, M. H. S.; Johnson, M. W.; Altomare, F.; Berkley, A. J.; Gildert, S.; Harris, R.; Johansson, J.; Bunyk, P.; Ladizinsky, E.; Tolkacheva, E.; Averin, D. V.

    2011-05-01

    We have developed a method for extracting the high-frequency noise spectral density of an rf-SQUID flux qubit from macroscopic resonant tunneling (MRT) rate measurements. The extracted noise spectral density is consistent with that of an ohmic environment up to frequencies ~4 GHz. We have also derived an expression for the MRT line shape expected for a noise spectral density consisting of such a broadband ohmic component and an additional strongly peaked low-frequency component. This hybrid model provides an excellent fit to experimental data across a range of tunneling amplitudes and temperatures.

  15. High frequency microphone measurements for transition detection on airfoils

    DEFF Research Database (Denmark)

    Døssing, Mads

    Time series of pressure fluctuations has been obtained using high frequency microphones distributed over the surface of airfoils undergoing wind tunnel tests in the LM Windtunnel, owned by ’LM Glasfiber’, Denmark. The present report describes the dataanalysis, with special attention given...... to transition detection. It is argued that the transition point can be detected by observing the increase in the mean of the Fourier spectre and that thismethod is very stable froma numerical point of view. Other important issues are also discussed, e.g. the variation of pressure standard deviations (sound...

  16. Planck 2013 results. VI. High Frequency Instrument data processing

    OpenAIRE

    Planck Collaboration; Ade, P. A. R.; Aghanim, N.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A. J.; Barreiro, R. B.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.

    2013-01-01

    We describe the processing of the 531 billion raw data samples from the High Frequency Instrument (HFI), which we performed to produce six temperature maps from the first 473 days of Planck-HFI survey data. These maps provide an accurate rendition of the sky emission at 100, 143, 217, 353, 545, and 857GHz with an angular resolution ranging from 9.́7 to 4.́6. The detector noise per (effective) beam solid angle is respectively, 10, 6 , 12, and 39 μK in the four lowest HFI frequency channels (10...

  17. Very High Frequency Interleaved Self-Oscillating Resonant SEPIC Converter

    DEFF Research Database (Denmark)

    Kovacevic, Milovan; Knott, Arnold; Andersen, Michael A. E.

    2013-01-01

    This paper describes analysis and design procedure of an interleaved, self-oscillating resonant SEPIC converter, suitable for operation at very high frequencies (VHF) ranging from 30 MHz to 300 MHz. The presented circuit consists of two resonant SEPIC DC-DC converters, and a capacitive...... interconnection network between the switches which provides self-oscillating and interleaved operation. A design approach to ensure zero voltage switching (ZVS) condition of the MOSFET devices is provided. To verify the proposed method, an 11 W, 50 MHz prototype was built using low-cost VDMOS devices...

  18. Articulated pipes conveying fluid pulsating with high frequency

    DEFF Research Database (Denmark)

    Jensen, Jakob Søndergaard

    1999-01-01

    Stability and nonlinear dynamics of two articulated pipes conveying fluid with a high-frequency pulsating component is investigated. The non-autonomous model equations are converted into autonomous equations by approximating the fast excitation terms with slowly varying terms. The downward hangin...... is shown to affect the nonlinear behavior of the system, e.g. bifurcation types can change from supercritical to subcritical, creating several coexisting stable solutions and also anti-symmetrical flutter may appear.......Stability and nonlinear dynamics of two articulated pipes conveying fluid with a high-frequency pulsating component is investigated. The non-autonomous model equations are converted into autonomous equations by approximating the fast excitation terms with slowly varying terms. The downward hanging....... An approximate nonlinear solution for small-amplitude flutter oscillations is obtained using a fifth-order multiple scales perturbation method, and large-amplitude oscillations are examined by numerical integration of the autonomous model equations, using a path-following algorithm. The pulsating fluid component...

  19. Features of the high frequency power transformer calculation

    Directory of Open Access Journals (Sweden)

    D.A. Zabarilo

    2013-06-01

    Full Text Available Purpose. The windings of power transformers have low resistance value and a most inductance, which reduces the rate of rise of current in the windings. Therefore, when the estimated amount of current is set one should make sure of the possibility of achieving it. As inductance is characterized by a short-circuit voltage, it is necessary to develop a technique for determining the maximum magnitude of the current in the windings of the transformer according to the short-circuit voltage and operating frequency. Methodology. The classical method of calculation of transient processes to determine the value of the transient current of the transformer windings to achieve purpose is used. Findings. The nature of the transient current in the windings of high-frequency transformer, which is powered by a voltage inverter is investigated and analyzed. Originality. The method for determining the maximum amount of current depending on the short-circuit voltage and frequency of the applied voltage with other set-up parameters was proposed. Practical value. The proposed method allows determining the maximum value of the current in the windings of the high-frequency transformer including its RL-parameters. This will let compare the value of a given current with possible depending on short-circuit voltage and frequency of the applied voltage. Research material may be applied for power transformers design.

  20. Saltating Snow Mechanics: High Frequency Particle Response to Mountain Wind

    Science.gov (United States)

    Aksamit, N. O.; Pomeroy, J. W.

    2015-12-01

    Blowing snow transport theory is currently limited by its dependency on the coupling of time-averaged measurements of particle saltation and suspension and wind speed. Details of the stochastic process of particle transport and complex bed interactions in the saltation layer, along with the influence of boundary-layer turbulence are unobservable with classic measurement techniques. In contrast, recent advances in two-phase sand transport understanding have been spurred by development of high-frequency wind and particle velocity measurement techniques. To advance the understanding of blowing snow, laser illuminated high-speed videography and ultrasonic anemometry were deployed in a mountain environment to examine saltation of snow over a natural snowpack in detail. A saltating snow measurement site was established at the Fortress Mountain Snow Laboratory, Alberta, Canada and instrumented with two Campbell CSAT3 ultrasonic anemometers, four Campbell SR50 ultrasonic snow depth sounders and a two dimensional Particle Tracking Velocimetry (PTV) system. Measurements were collected during nighttime blowing snow events, quantifying snow particle response to high frequency wind gusts. This novel approach permits PTV to step beyond mean statistics of snow transport by identifying sub-species of saltation motion in the first 20 mm above the surface, as well as previously overlooked initiation processes, such as tumbling aggregate snow crystals ejecting smaller grains, then eventually disintegrating and bouncing into entrainment. Spectral characteristics of snow particle ejection and saltation dynamics were also investigated. These unique observations are starting to inform novel conceptualizations of saltating snow transport mechanisms.

  1. High-Frequency Quantitative Ultrasound Imaging of Cancerous Lymph Nodes

    Science.gov (United States)

    Mamou, Jonathan; Coron, Alain; Hata, Masaki; Machi, Junji; Yanagihara, Eugene; Laugier, Pascal; Feleppa, Ernest J.

    2009-07-01

    High-frequency ultrasound (HFU) offers a means of investigating biological tissue at the microscopic level. High-frequency, quantitative-ultrasound (QUS) methods were developed to characterize freshly-dissected lymph nodes of cancer patients. Three-dimensional (3D) ultrasound data were acquired from lymph nodes using a 25.6-MHz center-frequency transducer. Each node was inked prior to 3D histological fixation to recover orientation after sectioning. Backscattered echo signals were processed to yield two QUS estimates associated with tissue microstructure: scatterer size and acoustic concentration. The QUS estimates were computed following established methods using a Gaussian scattering model. Four lymph nodes from a patient with stage-3 colon cancer were evaluated as an illustrative case. QUS images were generated for this patient by expressing QUS estimates as color-encoded pixels and overlaying them on conventional gray-scale B-mode images. The single metastatic node had an average scatterer size that was significantly larger than the average scatterer size of the other nodes, and the statistics of both QUS estimates in the metastatic node showed greater variance than the statistics of the other nodes. Results indicate that the methods may provide a useful means of identifying small metastatic foci in dissected lymph nodes that might not be detectable using current standard pathology procedures.

  2. Design and development of ITER high-frequency magnetic sensor

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Y., E-mail: Yunxing.Ma@iter.org [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Fircroft Engineering, Lingley House, 120 Birchwood Point, Birchwood Boulevard, Warrington, WA3 7QH (United Kingdom); Vayakis, G. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France); Begrambekov, L.B. [National Research Nuclear University (MEPhI), 115409, Moscow, Kashirskoe shosse 31 (Russian Federation); Cooper, J.-J. [Culham Centre for Fusion Energy (CCFE), Abingdon, Oxfordshire OX14 3DB (United Kingdom); Duran, I. [IPP Prague, Za Slovankou 1782/3, 182 00 Prague 8 (Czech Republic); Hirsch, M.; Laqua, H.P. [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, Wendelsteinstraße 1, D-17491 Greifswald (Germany); Moreau, Ph. [CEA Cadarache, 13108 Saint Paul lez Durance Cedex (France); Oosterbeek, J.W. [Eindhoven University of Technology (TU/e), PO Box 513, 5600 MB Eindhoven (Netherlands); Spuig, P. [CEA Cadarache, 13108 Saint Paul lez Durance Cedex (France); Stange, T. [Max-Planck-Institut für Plasmaphysik, Teilinstitut Greifswald, Wendelsteinstraße 1, D-17491 Greifswald (Germany); Walsh, M. [ITER Organization, Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul Lez Durance Cedex (France)

    2016-11-15

    Highlights: • ITER high-frequency magnetic sensor system has been designed. • Prototypes have been successfully manufactured. • Manufactured prototypes have been tested in various labs. • Test results experimentally validated the design. - Abstract: High-frequency (HF) inductive magnetic sensors are the primary ITER diagnostic set for Toroidal Alfvén Eigenmodes (TAE) detection, while they also supplement low-frequency MHD and plasma equilibrium measurements. These sensors will be installed on the inner surface of ITER vacuum vessel, operated in a harsh environment with considerable neutron/nuclear radiation and high thermal load. Essential components of the HF sensor system, including inductive coil, electron cyclotron heating (ECH) shield, electrical cabling and termination load, have been designed to meet ITER measurement requirements. System performance (e.g. frequency response, thermal conduction) has been assessed. A prototyping campaign was initiated to demonstrate the manufacturability of the designed components. Prototypes have been produced according to the specifications. A series of lab tests have been performed to examine assembly issues and validate electrical and thermo-mechanical aspects of the design. In-situ microwave radiation test has been conducted in the MISTRAL test facility at IPP-Greifswald to experimentally examine the microwave shielding efficiency and structural integrity of the ECH shield. Low-power microwave attenuation measurement and scanning electron microscopic inspection were conducted to probe and examine the quality of the metal coating on the ECH shield.

  3. Normocapnic high frequency oscillatory hyperventilation increases oxygenation in pigs.

    Science.gov (United States)

    Roubík, K; Pachl, J; Zábrodský, V

    2011-01-01

    High frequency oscillatory ventilation (HFOV), contrary to conventional ventilation, enables a safe increase in tidal volume (V(T)) without endangering alveoli by volutrauma or barotrauma. The aim of the study is to introduce the concept of normocapnic high frequency oscillatory hyperventilation and to assess its effect upon oxygen gain under experimental conditions. Laboratory pigs (n = 9) were investigated under total intravenous anesthesia in three phases. Phase 1: Initial volume controlled HFOV period. Phase 2: Hyperventilation--V(T) was increased by (46 +/- 12) % when compared to normocapnic V(T) during phase 1. All other ventilatory parameters were unchanged. A significant increase in PaO(2) (by 3.75 +/- 0.52 kPa, p hyperventilation was achieved by an iterative increase in the CO(2) fraction in the inspiratory gas by a CO(2) admixture. All ventilatory parameters were unchanged. A significant increase in PaO(2) (by 3.79 +/- 0.73 kPa, p hyperventilation offers a lung protective strategy that significantly improves oxygenation whilst preserving normocapnia.

  4. Carbon nanotube transistor based high-frequency electronics

    Science.gov (United States)

    Schroter, Michael

    At the nanoscale carbon nanotubes (CNTs) have higher carrier mobility and carrier velocity than most incumbent semiconductors. Thus CNT based field-effect transistors (FETs) are being considered as strong candidates for replacing existing MOSFETs in digital applications. In addition, the predicted high intrinsic transit frequency and the more recent finding of ways to achieve highly linear transfer characteristics have inspired investigations on analog high-frequency (HF) applications. High linearity is extremely valuable for an energy efficient usage of the frequency spectrum, particularly in mobile communications. Compared to digital applications, the much more relaxed constraints for CNT placement and lithography combined with already achieved operating frequencies of at least 10 GHz for fabricated devices make an early entry in the low GHz HF market more feasible than in large-scale digital circuits. Such a market entry would be extremely beneficial for funding the development of production CNTFET based process technology. This talk will provide an overview on the present status and feasibility of HF CNTFET technology will be given from an engineering point of view, including device modeling, experimental results, and existing roadblocks. Carbon nanotube transistor based high-frequency electronics.

  5. Planck 2013 results. VI. High Frequency Instrument data processing

    CERN Document Server

    Ade, P.A.R.; Armitage-Caplan, C.; Arnaud, M.; Ashdown, M.; Atrio-Barandela, F.; Aumont, J.; Baccigalupi, C.; Banday, A.J.; Barreiro, R.B.; Battaner, E.; Benabed, K.; Benoît, A.; Benoit-Lévy, A.; Bernard, J. -P.; Bersanelli, M.; Bielewicz, P.; Bobin, J.; Bock, J.J.; Bond, J.R.; Borrill, J.; Bouchet, F.R.; Boulanger, F.; Bowyer, J.W.; Bridges, M.; Bucher, M.; Burigana, C.; Cardoso, J. -F.; Catalano, A.; Chamballu, A.; Chary, R. -R.; Chen, X.; Chiang, L. -Y; Chiang, H.C.; Christensen, P.R.; Church, S.; Clements, D.L.; Colombi, S.; Colombo, L.P.L.; Combet, C.; Couchot, F.; Coulais, A.; Crill, B.P.; Curto, A.; Cuttaia, F.; Danese, L.; Davies, R.D.; Davis, R.J.; de Bernardis, P.; de Rosa, A.; de Zotti, G.; Delabrouille, J.; Delouis, J. -M.; Désert, F. -X.; Dickinson, C.; Diego, J.M.; Dole, H.; Donzelli, S.; Doré, O.; Douspis, M.; Dunkley, J.; Dupac, X.; Efstathiou, G.; Enßlin, T.A.; Eriksen, H.K.; Finelli, F.; Forni, O.; Frailis, M.; Fraisse, A.A.; Franceschi, E.; Galeotta, S.; Ganga, K.; Giard, M.; Giardino, G.; Girard, D.; Giraud-Héraud, Y.; González-Nuevo, J.; Górski, K.M.; Gratton, S.; Gregorio, A.; Gruppuso, A.; Gudmundsson, J.E.; Hansen, F.K.; Hanson, D.; Harrison, D.; Helou, G.; Henrot-Versillé, S.; Herent, O.; Hernández-Monteagudo, C.; Herranz, D.; Hildebrandt, S.R.; Hivon, E.; Hobson, M.; Holmes, W.A.; Hornstrup, A.; Hou, Z.; Hovest, W.; Huffenberger, K.M.; Hurier, G.; Jaffe, T.R.; Jaffe, A.H.; Jones, W.C.; Juvela, M.; Keihänen, E.; Keskitalo, R.; Kisner, T.S.; Kneissl, R.; Knoche, J.; Knox, L.; Kunz, M.; Kurki-Suonio, H.; Lagache, G.; Lamarre, J. -M.; Lasenby, A.; Laureijs, R.J.; Lawrence, C.R.; Jeune, M. Le; Leonardi, R.; Leroy, C.; Lesgourgues, J.; Liguori, M.; Lilje, P.B.; Linden-Vørnle, M.; López-Caniego, M.; Lubin, P.M.; Macías-Pérez, J.F.; MacTavish, C.J.; Maffei, B.; Mandolesi, N.; Maris, M.; Marshall, D.J.; Martin, P.G.; Martínez-González, E.; Masi, S.; Matarrese, S.; Matthai, F.; Mazzotta, P.; McGehee, P.; Meinhold, P.R.; Melchiorri, A.; Mendes, L.; Mennella, A.; Migliaccio, M.; Mitra, S.; Miville-Deschênes, M. -A.; Moneti, A.; Montier, L.; Morgante, G.; Mortlock, D.; Mottet, S.; Munshi, D.; Naselsky, P.; Nati, F.; Natoli, P.; Netterfield, C.B.; Nørgaard-Nielsen, H.U.; North, C.; Noviello, F.; Novikov, D.; Novikov, I.; Orieux, F.; Osborne, S.; Oxborrow, C.A.; Paci, F.; Pagano, L.; Pajot, F.; Paladini, R.; Paoletti, D.; Pasian, F.; Patanchon, G.; Perdereau, O.; Perotto, L.; Perrotta, F.; Piacentini, F.; Piat, M.; Pierpaoli, E.; Pietrobon, D.; Plaszczynski, S.; Pointecouteau, E.; Polenta, G.; Ponthieu, N.; Popa, L.; Poutanen, T.; Pratt, G.W.; Prézeau, G.; Prunet, S.; Puget, J. -L.; Rachen, J.P.; Racine, B.; Reach, W.T.; Rebolo, R.; Reinecke, M.; Remazeilles, M.; Renault, C.; Ricciardi, S.; Riller, T.; Ristorcelli, I.; Rocha, G.; Rosset, C.; Roudier, G.; Rowan-Robinson, M.; Rusholme, B.; Sanselme, L.; Santos, D.; Sauvé, A.; Savini, G.; Shellard, E.P.S.; Spencer, L.D.; Starck, J. -L.; Stolyarov, V.; Stompor, R.; Sudiwala, R.; Sureau, F.; Sutton, D.; Suur-Uski, A. -S.; Sygnet, J. -F.; Tauber, J.A.; Tavagnacco, D.; Techene, S.; Terenzi, L.; Tomasi, M.; Tristram, M.; Tucci, M.; Umana, G.; Valenziano, L.; Valiviita, J.; Van Tent, B.; Vibert, L.; Vielva, P.; Villa, F.; Vittorio, N.; Wade, L.A.; Wandelt, B.D.; White, S.D.M.; Yvon, D.; Zacchei, A.; Zonca, A.

    2014-01-01

    We describe the processing of the 531 billion raw data samples from the High Frequency Instrument (hereafter HFI), which we performed to produce six temperature maps from the first 473 days of Planck-HFI survey data. These maps provide an accurate rendition of the sky emission at 100, 143, 217, 353, 545, and 857 GHz with an angular resolution ranging from 9.7 to 4.6 arcmin. The detector noise per (effective) beam solid angle is respectively, 10, 6, 12 and 39 microKelvin in HFI four lowest frequency channel (100--353 GHz) and 13 and 14 kJy/sr for the 545 and 857 GHz channels. Using the 143 GHz channel as a reference, these two high frequency channels are intercalibrated within 5% and the 353 GHz relative calibration is at the percent level. The 100 and 217 GHz channels, which together with the 143 GHz channel determine the high-multipole part of the CMB power spectrum (50 < l <2500), are intercalibrated at better than 0.2 %.

  6. High-frequency fatigue after alpine slalom skiing.

    Science.gov (United States)

    Tomazin, Katja; Dolenec, Ales; Strojnik, Vojko

    2008-05-01

    The aim of the study was to examine the presence of high-frequency fatigue (HFF) after simulated alpine slalom skiing race. Eight male alpine skiers (18.4+/-1.2 y.a., 182.3+/-3.5 cm, 80.5+/-3.4 kg) completed the study. Their average FIS points in slalom were 30.1+/-5.4. After the special skiing warm up, the following initial tests were performed: blood lactate concentration, twitch response of the relaxed VL muscle, knee torque during low- (20 Hz) and high-frequency (100 Hz) electrical stimulation of vastus lateralis muscle, and maximum, voluntary isometric knee extension torque. Then, subjects performed slalom with 45 gates, whose duration was approximately 45 s. The same test sequence, except blood lactate test was used after slalom and the measurements started exactly 60 and 180 s after slalom. Blood lactate concentration measurement started exactly 3 and 5 min after slalom. A 1x3 repeated measures; time-series design was used with one within factor of time (before 60 s, and 180 s after skiing). The average blood lactate level increased from 1.6 (0.6) pre-slalom to 7.1(1.6) mmol(-l) 15 min post-slalom (F2,14=70.1; P<0.001). Sixty seconds after slalom, twitch contraction time shortened from 78.2 (5.7) pre-slalom to 66.0 (7.2) ms post-slalom (F1.19,8.3=9.9; P<0.05). Peak twitch torque was potentiated from 21.6 (3.8) to 26.4 (5.3) Nm (F2,14=16.7; P<0.05). Slalom reduced high-frequency torque from 64.4 (35) to 58.2 (34.2) Nm 60 s post-slalom (F2,14=3.8; P<0.05), while low-frequency torque stayed virtually the same. Slalom induced HFF, which is typical of SSC exercises of maximum intensity and short duration.

  7. High frequency conductivity of hot electrons in carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Amekpewu, M., E-mail: mamek219@gmail.com [Department of Applied Physics, University for Development Studies, Navrongo (Ghana); Mensah, S.Y. [Department of Physics, College of Agriculture and Natural Sciences, U.C.C. (Ghana); Musah, R. [Department of Applied Physics, University for Development Studies, Navrongo (Ghana); Mensah, N.G. [Department of Mathematics, College of Agriculture and Natural Sciences, U.C.C. (Ghana); Abukari, S.S.; Dompreh, K.A. [Department of Physics, College of Agriculture and Natural Sciences, U.C.C. (Ghana)

    2016-05-01

    High frequency conductivity of hot electrons in undoped single walled achiral Carbon Nanotubes (CNTs) under the influence of ac–dc driven fields was considered. We investigated semi-classically Boltzmann's transport equation with and without the presence of the hot electrons’ source by deriving the current densities in CNTs. Plots of the normalized current density versus frequency of ac-field revealed an increase in both the minimum and maximum peaks of normalized current density at lower frequencies as a result of a strong injection of hot electrons. The applied ac-field plays a twofold role of suppressing the space-charge instability in CNTs and simultaneously pumping an energy for lower frequency generation and amplification of THz radiations. These have enormous promising applications in very different areas of science and technology.

  8. Slow high-frequency effects in mechanics: problems, solutions, potentials

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    2005-01-01

    them are introduced first in terms of simple physical examples, and then in generalized form for mathematical models covering broad classes of discrete and continuous mechanical systems. Several application examples are summarized. Three mathematical tools for analyzing HFE effects are described......Strong high-frequency excitation (HFE) may change the ‘slow’ (i.e. effective or average) properties of mechanical systems, e.g. their stiffness, natural frequencies, equilibriums, equilibrium stability, and bifurcation paths. This tutorial describes three general HFE effects: Stiffening...... – an apparent change in the stiffness associated with an equilibrium; Biasing – a tendency for a system to move towards a particular state which does not exist or is unstable without HFE; and Smoothening – a tendency for discontinuities to be apparently smeared out by HFE. The effects and a method for analyzing...

  9. Structural Health Monitoring Using High-Frequency Electromechanical Impedance Signatures

    Directory of Open Access Journals (Sweden)

    Wei Yan

    2010-01-01

    Full Text Available An overview of recent advances in electromechanical impedance- (EMI- based structural health monitoring is presented in this paper. The basic principle of the EMI method is to use high-frequency excitation to sense the local area of a structure. Changes in impedance indicate changes in the structure, which in turn indicate that damages appear. An accurate EMI model based on the method of reverberation-ray matrix is introduced to correlate changes in the signatures to physical parameters of structures for damage detection. Comparison with other numerical results and experimental data validates the present model. A brief remark of the feasibility of implementing the EMI method is considered and the effects of some physical parameters on EMI technique are also discussed.

  10. High frequency microphone measurements for transition detection on airfoils

    Energy Technology Data Exchange (ETDEWEB)

    Doessing, M.

    2008-05-15

    Time series of pressure fluctuations has been obtained using high frequency microphones distributed over the surface of airfoils undergoing wind tunnel tests in the LM Windtunnel, owned by 'LM Glasfiber', Denmark. The present report describes the dataanalysis, with special attention given to transition detection. It is argued that the transition point can be detected by observing the increase in the mean of the Fourier spectre and that thismethod is very stable froma numerical point of view. Other important issues are also discussed, e.g. the variation of pressure standard deviations (sound pressure) and Tollmien-Schlichting frequencies. The tests were made at Reynolds and Mach numbers corresponding to the operating conditions of a typical horizontal axis wind turbine (HAWT). The Risoe B1-18, Risoe C2-18 and NACA0015 profiles were tested and the measured transition points are reported. (au)

  11. Graphene Quantum Capacitors for High Frequency Tunable Analog Applications.

    Science.gov (United States)

    Moldovan, Clara F; Vitale, Wolfgang A; Sharma, Pankaj; Tamagnone, Michele; Mosig, Juan R; Ionescu, Adrian M

    2016-08-10

    Graphene quantum capacitors (GQC) are demonstrated to be enablers of radio-frequency (RF) functions through voltage-tuning of their capacitance. We show that GQC complements MEMS and MOSFETs in terms of performance for high frequency analog applications and tunability. We propose a CMOS compatible fabrication process and report the first experimental assessment of their performance at microwaves frequencies (up to 10 GHz), demonstrating experimental GQCs in the pF range with a tuning ratio of 1.34:1 within 1.25 V, and Q-factors up to 12 at 1 GHz. The figures of merit of graphene variable capacitors are studied in detail from 150 to 350 K. Furthermore, we describe a systematic, graphene specific approach to optimize their performance and predict the figures of merit achieved if such a methodology is applied.

  12. The wave buoy analogy - estimating high-frequency wave excitations

    DEFF Research Database (Denmark)

    Nielsen, Ulrik Dam

    2008-01-01

    The paper deals with the wave buoy analogy where a ship is considered as a wave buoy, so that measured ship responses are used as a basis to estimate wave spectra and associated sea state parameters. The study presented follows up on a previous paper, Nielsen [Nielsen UD. Response-based estimation...... of sea state parameters — influence of filtering. Ocean Engineering 2007;34:1797–810.], where time series of ship responses were generated from a known wave spectrum for the purpose of the inverse process — the estimation of the underlying wave excitations. Similar response generations and vice versa...... be estimated reasonably well, even considering high-frequency wave components of a wind sea wave spectrum....

  13. Very High Frequency Switch-Mode Power Supplies

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre

    The importance of technology and electronics in our daily life is constantly increasing. At the same time portability and energy efficiency are currently some of the hottest topics. This creates a huge need for power converters in a compact form factor and with high efficiency, which can supply...... band gap semiconductors and integrated power supplies. Afterwards a wide range of topologies suited for operation at very high frequencies is investigated and the most promising ones are tested experimentally. Through a comparison of these topologies the class DE inverter is found to be superior...... to the other alternatives, at least for converters with hundreds of volts as input and a few tens of watts output power. A class DE inverter does however require a high side gate drive, which have never been presented before for these frequencies and voltages. This thesis presents the worlds first high side...

  14. High frequency ultrasound evaluation of traumatic peripheral nerve injuries.

    Science.gov (United States)

    Hollister, Anne M; Simoncini, Alberto; Sciuk, Adam; Jordan, Jenee'

    2012-01-01

    Accurate diagnosis and localization of peripheral nerve traumatic injury remains difficult. Early diagnosis and repair of nerve discontinuity lesions lead to better outcome than delayed repair. We used new high frequency ultrasound to evaluate 24 patients with 29 traumatic nerve injuries. There were a variety of causes including gunshot wounds, blunt injuries, burns, stabbings, and motor vehicle accidents. The patients were then either treated surgically with nerve status directly observed or followed clinically for recovery of nerve function. The ultrasound findings correspond with the clinical outcome of 28 of the 29 nerves. While this is a study limited by a small patient number, ultrasound evaluation should be considered in the evaluation of nerve injury and can lead to early diagnosis and treatment of surgical nerve injuries.

  15. Dynamical structures of high-frequency financial data

    Science.gov (United States)

    Kim, Kyungsik; Yoon, Seong-Min; Kim, SooYong; Chang, Ki-Ho; Kim, Yup; Hoon Kang, Sang

    2007-03-01

    We study the dynamical behavior of high-frequency data from the Korean Stock Price Index (KOSPI) using the movement of returns in Korean financial markets. The dynamical behavior of a binarized series of our models is not completely random. In addition, the conditional probability is numerically estimated from a return series of KOSPI tick data. Non-trivial probability structures can be constituted from binary time series of autoregressive (AR), logit, and probit models, for which the Akaike Information Criterion shows a minimum value at the 15th order. From our results, we find that the value of the correct match ratio for the AR model is slightly larger than that derived by other models.

  16. Optimized tissue heating by adopting high frequency electrotherapy

    Directory of Open Access Journals (Sweden)

    Jae-cheol Lee

    2015-11-01

    Full Text Available We have developed an electronics circuit that generates a high voltage with a frequency of 0.3–2 MHz to build an electro therapy system that can optimize tissue heating characteristics. These characteristics are used in medical applications. This paper is focused on the analysis of high frequency electro-therapy system to optimize tissue heating with the help of a high voltage pulse signal, which peak voltage is almost 2 kV. This optimized tissue heating between the inner tissue and the thermal distributions has examined in terms of frequency and voltage. The target tissue heating is composed of a single electrode in an experiment that has especially conducted to find the tissue heating characteristics. In the end, a new method for electro-therapy is developed, which is applicable to a specific tissue depth.

  17. High frequency techniques an introduction to RF and microwave engineering

    CERN Document Server

    White, Joseph F

    2004-01-01

    A practical guide for today's wireless engineerHigh Frequency Techniques: An Introduction to RF and Microwave Engineering is a clearly written classical circuit and field theory text illustrated with modern computer simulation software. The book's ten chapters cover: *The origins and current uses of wireless transmission *A review of AC analysis, Kirchhoff's laws, RLC elements, skin effect, and introduction to the use of computer simulation software*Resonators, Q definitions, and Q-based impedance matching *Transmission lines, waves, VSWR, reflection phenomena, Fano's reflection bandwidth limits, telegrapher, and impedance transformation equations*Development and in-depth use of the Smith Chart *Matrix algebra with Z, Y, ABCD, S, and T matrix applications*An unusually thorough introduction to electromagnetic field theory, step-by-step development of vector calculus, Maxwell's equations, waveguides, propagation, and antennas*Backward wave, branch line, rat race and Wilkinson couplers, impedance measurements, a...

  18. High frequency modulation circuits based on photoconductive wide bandgap switches

    Energy Technology Data Exchange (ETDEWEB)

    Sampayan, Stephen

    2018-02-13

    Methods, systems, and devices for high voltage and/or high frequency modulation. In one aspect, an optoelectronic modulation system includes an array of two or more photoconductive switch units each including a wide bandgap photoconductive material coupled between a first electrode and a second electrode, a light source optically coupled to the WBGP material of each photoconductive switch unit via a light path, in which the light path splits into multiple light paths to optically interface with each WBGP material, such that a time delay of emitted light exists along each subsequent split light path, and in which the WBGP material conducts an electrical signal when a light signal is transmitted to the WBGP material, and an output to transmit the electrical signal conducted by each photoconductive switch unit. The time delay of the photons emitted through the light path is substantially equivalent to the time delay of the electrical signal.

  19. Planck early results. VI. The High Frequency Instrument data processing

    DEFF Research Database (Denmark)

    Colley, J.-M.; Bartlett, J.G.; Bucher, M.

    2011-01-01

    We describe the processing of the 336 billion raw data samples from the High Frequency Instrument (HFI) which we performed to produce six temperature maps from the first 295 days of Planck-HFI survey data. These maps provide an accurate rendition of the sky emission at 100, 143, 217, 353, 545...... by the HFI Data Processing Centre reach our goals in terms of sensitivity, resolution, and photometric accuracy. They are already sufficiently accurate and well-characterised to allow scientific analyses which are presented in an accompanying series of early papers. At this stage, HFI data appears...... to be of high quality and we expect that with further refinements of the data processing we should be able to achieve, or exceed, the science goals of the Planck project. © ESO, 2011....

  20. Material control and surveillance for high frequency access vaults project

    Energy Technology Data Exchange (ETDEWEB)

    Longmire, V. L. (Victoria L.); Stevens, R. S. (Rebecca S.); Martinez, B. J. (Benny J.); Butler, G. W. (Gilbert W.); Huang, J. Y. (John Y.); Pickett, C. (Chris); Younkin, J. (James); Dunnigan, Janelle; Gaby, Jane; Lawson, R. (Roger)

    2004-01-01

    The 'Material Control and Surveillance for High Frequency Access Vaults' project sponsored by United States Department of Energy's Office of Security Policy, Policy Integration and Technical Support Program (SO-20.3) focuses on enhancing nuclear materials control and surveillance in vaults that are frequently accessed. The focus of this effort is to improve materials control and accountability (MC&A) while decreasing the operational impact of these activities. Los Alamos and Y-12 have developed a testbed at the Los Alamos National Laboratory for evaluating and demonstrating integrated technologies for use in enhancing materials control and accountability in active nuclear material storage vaults. An update will be provided on the new systems demonstrated in the test-bed including a 'confirmatory cart' for expediting the performance of inventory and radio-frequency actuated video that demonstrates the concept of automated data entry for materials moving between MBA's. The United States Department of Energy's Office of Security Policy, Policy Integration and Technical Support Program (SO-20.3) has sponsored a project where nuclear material inventory, control and surveillance systems are evaluated, developed, and demonstrated in an effort to provide technologies that reduce risk, increase material assurance, and provide cost-efficient alternatives to manpower-intensive physical inventory and surveillance approaches for working (high-frequency-access) vaults. This Fiscal Year has been largely focused on evaluating and developing components of two sub-systems that could be used either separately in nuclear material vaults or as part of a larger integrated system for nuclear materials accountability, control and surveillance.

  1. Electrokinetic particle-electrode interactions at high frequencies

    Science.gov (United States)

    Yariv, Ehud; Schnitzer, Ory

    2013-01-01

    We provide a macroscale description of electrokinetic particle-electrode interactions at high frequencies, where chemical reactions at the electrodes are negligible. Using a thin-double-layer approximation, our starting point is the set of macroscale equations governing the “bounded” configuration comprising of a particle suspended between two electrodes, wherein the electrodes are governed by a capacitive charging condition and the imposed voltage is expressed as an integral constraint. In the large-cell limit the bounded model is transformed into an effectively equivalent “unbounded” model describing the interaction between the particle and a single electrode, where the imposed-voltage condition is manifested in a uniform field at infinity together with a Robin-type condition applying at the electrode. This condition, together with the standard no-flux condition applying at the particle surface, leads to a linear problem governing the electric potential in the fluid domain in which the dimensionless frequency ω of the applied voltage appears as a governing parameter. In the high-frequency limit ω≫1 the flow is dominated by electro-osmotic slip at the particle surface, the contribution of electrode electro-osmosis being O(ω-2) small. That simplification allows for a convenient analytical investigation of the prevailing case where the clearance between the particle and the adjacent electrode is small. Use of tangent-sphere coordinates allows to calculate the electric and flows fields as integral Hankel transforms. At large distances from the particle, along the electrode, both fields decay with the fourth power of distance.

  2. High-frequency underwater plasma discharge application in antibacterial activity

    Science.gov (United States)

    Ahmed, M. W.; Choi, S.; Lyakhov, K.; Shaislamov, U.; Mongre, R. K.; Jeong, D. K.; Suresh, R.; Lee, H. J.

    2017-03-01

    Plasma discharge is a novel disinfection and effectual inactivation approach to treat microorganisms in aqueous systems. Inactivation of Gram-negative Escherichia coli ( E. coli) by generating high-frequency, high-voltage, oxygen (O2) injected and hydrogen peroxide (H2O2) added discharge in water was achieved. The effect of H2O2 dose and oxygen injection rate on electrical characteristics of discharge and E. coli disinfection has been reported. Microbial log reduction dependent on H2O2 addition with O2 injection was observed. The time variation of the inactivation efficiency quantified by the log reduction of the initial E. coli population on the basis of optical density measurement was reported. The analysis of emission spectrum recorded after discharge occurrence illustrated the formation of oxidant species (OH•, H, and O). Interestingly, the results demonstrated that O2 injected and H2O2 added, underwater plasma discharge had fabulous impact on the E. coli sterilization. The oxygen injection notably reduced the voltage needed for generating breakdown in flowing water and escalated the power of discharge pulses. No impact of hydrogen peroxide addition on breakdown voltage was observed. A significant role of oxidant species in bacterial inactivation also has been identified. Furthermore the E. coli survivability in plasma treated water with oxygen injection and hydrogen peroxide addition drastically reduced to zero. The time course study also showed that the retardant effect on E. coli colony multiplication in plasma treated water was favorable, observed after long time. High-frequency underwater plasma discharge based biological applications is technically relevant and would act as baseline data for the development of novel antibacterial processing strategies.

  3. High-frequency underwater plasma discharge application in antibacterial activity

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, M. W.; Choi, S.; Lyakhov, K.; Shaislamov, U. [Jeju National University, Department of Nuclear and Energy Engineering (Korea, Republic of); Mongre, R. K.; Jeong, D. K. [Jeju National University, Faculty of Biotechnology (Korea, Republic of); Suresh, R.; Lee, H. J., E-mail: hjlee@jejunu.ac.kr [Jeju National University, Department of Nuclear and Energy Engineering (Korea, Republic of)

    2017-03-15

    Plasma discharge is a novel disinfection and effectual inactivation approach to treat microorganisms in aqueous systems. Inactivation of Gram-negative Escherichia coli (E. coli) by generating high-frequency, high-voltage, oxygen (O{sub 2}) injected and hydrogen peroxide (H{sub 2}O{sub 2}) added discharge in water was achieved. The effect of H{sub 2}O{sub 2} dose and oxygen injection rate on electrical characteristics of discharge and E. coli disinfection has been reported. Microbial log reduction dependent on H{sub 2}O{sub 2} addition with O{sub 2} injection was observed. The time variation of the inactivation efficiency quantified by the log reduction of the initial E. coli population on the basis of optical density measurement was reported. The analysis of emission spectrum recorded after discharge occurrence illustrated the formation of oxidant species (OH{sup •}, H, and O). Interestingly, the results demonstrated that O{sub 2} injected and H{sub 2}O{sub 2} added, underwater plasma discharge had fabulous impact on the E. coli sterilization. The oxygen injection notably reduced the voltage needed for generating breakdown in flowing water and escalated the power of discharge pulses. No impact of hydrogen peroxide addition on breakdown voltage was observed. A significant role of oxidant species in bacterial inactivation also has been identified. Furthermore the E. coli survivability in plasma treated water with oxygen injection and hydrogen peroxide addition drastically reduced to zero. The time course study also showed that the retardant effect on E. coli colony multiplication in plasma treated water was favorable, observed after long time. High-frequency underwater plasma discharge based biological applications is technically relevant and would act as baseline data for the development of novel antibacterial processing strategies.

  4. Partial deletion 11q

    DEFF Research Database (Denmark)

    Hertz, Jens Michael; Tommerup, N; Sørensen, F B

    1995-01-01

    We describe the cytogenetic findings and the dysmorphic features in a stillborn girl with a large de novo terminal deletion of the long arm of chromosome 11. The karyotype was 46,XX,del(11)(q21qter). By reviewing previous reports of deletion 11q, we found that cleft lip and palate are most...

  5. A large deletion on chromosome 11 in acute intermittent porphyria.

    Science.gov (United States)

    Di Pierro, Elena; Besana, Valeria; Moriondo, Valeria; Brancaleoni, Valentina; Tavazzi, Dario; Casalgrandi, Giovanna; Ventura, Paolo; Rocchi, Emilio; Cappellini, Maria Domenica

    2006-01-01

    Acute intermittent porphyria (AIP) is an autosomal disorder caused by molecular abnormalities in the gene coding for hydroxymethylbilane synthase (HMBS), the third enzyme in the heme biosynthetic pathway. So far, more than 242 different mutations responsible for AIP have been identified in this gene. In an Italian family with typical clinical and biochemical signs of AIP, no mutation was found by direct sequencing of the entire hydroxymethylbilane synthase gene (HMBS). All the symptomatic patients showed apparent homozygosity and absence of mendelian segregation for eleven common polymorphisms along the gene. Excluding interference of polymorphisms in the primer sites, we assumed the presence of a complete HMBS gene deletion. In order to identify the size of this deletion, single nucleotide polymorphisms (SNPs) analysis was extended to flanking genes, H2A Histone Family member X (H2AFX) and Dolichyl-Phosphate N-Acetylglucosamine Phosphotransferase 1 (DPAGT1), downstream and Vacuolar protein sorting 11 (VPS11), upstream. Heterozygous polymorphisms in the VPS11 and DPAGT1 genes were found. Thus, we performed a Long-PCR with primers situated in regions outside the homozygous polymorphisms and we identified a double deletion with inversion on chromosome 11 (g22516974_22524062del7088, g22524062_22524278inv216, g22524278_22531093del6815). Even if the deletions include the entire HMBS and H2AFX genes and 1463 bp of the final portion of DPAGT1 gene, our patients had no other symptoms than AIP.

  6. High frequency modeling of power transformers. Stresses and diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Bjerkan, Eilert

    2005-05-15

    In this thesis a reliable, versatile and rigorous method for high frequency power transformer modeling is searched and established. The purpose is to apply this model to sensitivity analysis of FRA (Frequency Response Analysis) which is a quite new diagnostic method for assessing the mechanical integrity of power transformer windings on-site. The method should be versatile in terms of being able to estimate internal and external over voltages and resonances. Another important aspect is that the method chosen is suitable for real transformer geometries. In order to verify the suitability of the model for real transformers, a specific test-object is used. This is a 20MVA transformer, and details are given in chapter 1.4. The high frequency power transformer model is established from geometrical and constructional information from the manufacturer, together with available material characteristics. All circuit parameters in the lumped circuit representation are calculated based on these data. No empirical modifications need to be performed. Comparison shows capability of reasonable accuracy in the range from 10 khz to 1 MHz utilizing a disc-to-disc representation. A compromise between accuracy of model due to discretization and complexity of the model in a turn-to-turn representation is inevitable. The importance of the iron core is emphasized through a comparison of representations with/without the core included. Frequency-dependent phenomena are accurately represented using an isotropic equivalent for windings and core, even with a coarse mesh for the FEM-model. This is achieved through a frequency-dependent complex permeability representation of the materials. This permeability is deduced from an analytical solution of the frequency-dependent magnetic field inside the conductors and the core. The importance of dielectric losses in a transformer model is also assessed. Since published data on the high frequency properties of press board are limited, some initial

  7. Resent developments in high-frequency surface-wave techniques

    Science.gov (United States)

    Xia, J.; Pan, Y.; Zeng, C.

    2012-12-01

    High-frequency Rayleigh-wave methods, such as Multi-channel Analysis of Surface Waves (MASW), are getting increasingly attention in the near-surface geophysics and geotechnique community in the last 20 years because of their non-invasive, non-destructive, efficient, and low-cost advantages and their success in environmental and engineering applications. They are viewed by near-surface geophysics community as the one of most promise techniques in the future. However, they face unique problems related to extremely irregular velocity variations in near-surface geology or man-made constructions, for example, highway, foundation, dam, levee, jetty, etc., which are not solvable by techniques or algorithms widely used in earthquake seismology or oil/gas seismic exploration. We present solutions to the problems associated with near-surface materials that possess velocity inverse and high Poisson's ratio. Calculation of dispersion curves by existing algorithms may fail for some special velocity models due to velocity inverse (a high-velocity layer on the top of a low-velocity layer). Two velocity models are most common in near-surface applications. One is a low-velocity half space model and the other a high-velocity topmost layer. The former model results in a complex matrix that no roots can be found in the real number domain, which implies that no phase velocities can be calculated in certain frequency ranges based on current exist algorithms. A solution is to use the real part of the root of the complex number. It is well-known that phase velocities approach about 91% of the shear (S)-wave velocity of the topmost layer when wavelengths are much shorter than the thickness of the topmost layer. The later model, however, results in that phase velocities in a high-frequency range calculated using the current algorithms approach a velocity associated with the S-wave velocity of the second layer NOT the topmost layer. A solution to this problem is to use a two-layer model to

  8. Cobalt Nanoparticle Inks for Printed High Frequency Applications on Polycarbonate

    Science.gov (United States)

    Nelo, Mikko; Myllymäki, Sami; Juuti, Jari; Uusimäki, Antti; Jantunen, Heli

    2015-12-01

    In this work the high frequency properties of low curing temperature cobalt nanoparticle inks printed on polycarbonate substrates were investigated. The inks consisted of 30-70 vol.% metallic cobalt nanoparticles and poly (methylene methacrylate) polymer, having excellent adhesion on polycarbonate and a curing temperature of 110°C. The influence of binder material content on the electromagnetic properties of the ink was investigated using the shorted microstrip transmission-line perturbation method. Changes in mechanical properties were evaluated with adhesion tests using the pull-out strength test and the ASTM D 3359-B cross-hatch tape peel test. The microstructure of the printed patterns was investigated with field emission scanning electron microscopy (FESEM). The inks remained mechanically durable with metal contents up to 60 vol.%, achieving pull-off strength of up to 5.2 MPa and the highest marks in adhesion of the tape peel test. The inks obtained a relative permeability of 1.5-3 in the 45 MHz-10 GHz band with a magnetic loss tangent of 0.01-0.06. The developed inks can be utilized in various printed electronics applications such as antenna miniaturization, antenna substrates and magnetic sensors or sensing.

  9. Network Analyses for Space-Time High Frequency Wind Data

    Science.gov (United States)

    Laib, Mohamed; Kanevski, Mikhail

    2017-04-01

    Recently, network science has shown an important contribution to the analysis, modelling and visualization of complex time series. Numerous existing methods have been proposed for constructing networks. This work studies spatio-temporal wind data by using networks based on the Granger causality test. Furthermore, a visual comparison is carried out with several frequencies of data and different size of moving window. The main attention is paid to the temporal evolution of connectivity intensity. The Hurst exponent is applied on the provided time series in order to explore if there is a long connectivity memory. The results explore the space time structure of wind data and can be applied to other environmental data. The used dataset presents a challenging case study. It consists of high frequency (10 minutes) wind data from 120 measuring stations in Switzerland, for a time period of 2012-2013. The distribution of stations covers different geomorphological zones and elevation levels. The results are compared with the Person correlation network as well.

  10. Very High Frequency Galvanic Isolated Offline Power Supply

    DEFF Research Database (Denmark)

    Pedersen, Jeppe Arnsdorf

    inverters with a single combined rectifier. The converter designed to deliver 9 W to a 60 V LED load and is achieving an efficiency of 89.4% and a power density of 2.14 W3 . The development of this converter proof that offline VHF converter can be implemented with high efficiencies even for low power applications...... converters. During this Ph.D. thesis, different areas of an offline VHF converters are described, dur-ing the project different areas have been investigated such as, gate drive, synchronous rectifiers, PCB transformers, control of a resonant converter, galvanic isolation, EMC performance, power factor......During the last decades many researchers have turned their attention to raising the operation frequency of power converters to the very high frequency (VHF) range going from 30 MHz to 300 MHz. Increasing the operating frequency of a power converter leads to smaller energy storing components...

  11. High-Frequency Chest Compression: A Summary of the Literature

    Directory of Open Access Journals (Sweden)

    Cara F Dosman

    2005-01-01

    Full Text Available The purpose of the present literature summary is to describe high-frequency chest compression (HFCC, summarize its history and outline study results on its effect on mucolysis, mucus transport, pulmonary function and quality of life. HFCC is a mechanical method of self-administered chest physiotherapy, which induces rapid air movement in and out of the lungs. This mean oscillated volume is an effective method of mucolysis and mucus clearance. HFCC can increase independence. Some studies have shown that HFCC leads to more mucus clearance and better lung function compared with conventional chest physiotherapy. However, HFCC also decreases end-expiratory lung volume, which can lead to increased airway resistance and a decreased oscillated volume. Adding positive end-expiratory pressure to HFCC has been shown to prevent this decrease in end-expiratory lung volume and to increase the oscillated volume. It is possible that the HFCC-induced decrease in end-expiratory lung volume may result in more mucus clearance in airways that remain open by reducing airway size. Adjunctive methods, such as positive end-expiratory pressure, may not always be needed to make HFCC more effective.

  12. Fantoni’s Tracheostomy using Catheter High Frequency Jet Ventilation

    Directory of Open Access Journals (Sweden)

    P. Török

    2012-01-01

    Full Text Available Background: It has been shown previously that conventional ventilation delivered through a long cuffed endotracheal tube is associated with a high flow-resistance and frequent perioperative complications. Aim: We attempted to supersede the conventional ventilation by high-frequency jet ventilation through a catheter (HFJV-C and assess safety of the procedure. Material and methods: Using a translaryngeal tracheostomy kit, we performed a translaryngeal (Fantoni tracheostomy (TLT. Subsequently, we introduced a special 2-way prototype ventilatory catheter into the trachea via the TLT under bronchoscopic control. Satisfactory HFJV-C ventilation through the catheter was achieved in 218 patients. Results: There were no significant adverse effects on vital signs observed in the cohort during the study. The pH, SpO2, PaO2, and PaCO2 did not change significantly following the HFJV-C. The intrinsic PEEPi measured in trachea did not exceed 4—5 cm H2O during its application, which was significantly less than during the classical ventilation via the endotracheal tube fluctuating between 12 and 17 cm H2O. No serious medical complications occurred. Conclusion: The HFJV during Fantoni’s tracheostomy using the catheter HFJV-C proved to be a safe and effective method of lung ventilation at the intensive care unit. Key words: Translaryngeal tracheostomy, HFJV via catheter.

  13. High Frequency Mechanical Pyroshock Simulations for Payload Systems

    Energy Technology Data Exchange (ETDEWEB)

    BATEMAN,VESTA I.; BROWN,FREDERICK A.; CAP,JEROME S.; NUSSER,MICHAEL A.

    1999-12-15

    Sandia National Laboratories (SNL) designs mechanical systems with components that must survive high frequency shock environments including pyrotechnic shock. These environments have not been simulated very well in the past at the payload system level because of weight limitations of traditional pyroshock mechanical simulations using resonant beams and plates. A new concept utilizing tuned resonators attached to the payload system and driven with the impact of an airgun projectile allow these simulations to be performed in the laboratory with high precision and repeatability without the use of explosives. A tuned resonator has been designed and constructed for a particular payload system. Comparison of laboratory responses with measurements made at the component locations during actual pyrotechnic events show excellent agreement for a bandwidth of DC to 4 kHz. The bases of comparison are shock spectra. This simple concept applies the mechanical pyroshock simulation simultaneously to all components with the correct boundary conditions in the payload system and is a considerable improvement over previous experimental techniques and simulations.

  14. Tecnologia radio cognitiva en la banda ultra high frequency (UHF

    Directory of Open Access Journals (Sweden)

    Hernán Paz Penagos

    2014-01-01

    Full Text Available Mobile cellular communication companies in Colombia require more spectrum resources to expand their portfolio of services. However, additional frequency bands for that particular purpose are scarce, yet it is well known that there are many underutilized licensed bands. Therefore new radio technologies are being studied in order to solve this problem, e.g. Software Defined Radio SDR Cognitive Radio CR and Dynamic Spectrum Access DSA. These strategies recommend mobility across the radio spectrum to meet various needs and achieve greater efficiency when managing such a scarce resource. In this context, a case study is presented in an attempt to examine the require¬ments that must be met for the implementation of cognitive radio networks in Bogota. The case study includes evaluation for the possibility of migration from cellular communications to cognitive radio since the bands assigned to UltraHigh Frequency UHF television offer possible free-of-interference coexistence between the two services (i.e. Cellular and TV. The study shows feasibility to migration; however, the implementations of cognitive radio need availability of hardware, software and flexible radio platforms.

  15. Algorithmic and high-frequency trading in Borsa Istanbul

    Directory of Open Access Journals (Sweden)

    Oguz Ersan

    2016-12-01

    Full Text Available This paper investigates the levels of algorithmic trading (AT and high-frequency trading (HFT in an emerging market, Borsa Istanbul (BIST, utilizing a dataset of 354 trading days between January 2013 and May 2014. We find an upward trend in AT by using common proxies: number of messages per minute and algo_trad of Hendershott et al. (2011. Mean algo_trad for BIST 100 index constituents varies between −18 and −13 which is parallel to 2003–2005 levels of NASDAQ large cap stocks. Initially, we measure HFT involvement by detecting linked messages as in the way proposed in Hasbrouck and Saar (2013. Next, we propose an extended HFT measure which captures various HFT strategies. This measure attributes approximately 6% of the orders to HFT. HFT involvement is higher in large orders (11.96%, in orders submitted by portfolio/fund management firms (10.40%, after improvement of BIST's order submission platform and tick size reduction for certain stocks.

  16. High frequency guided wave propagation in monocrystalline silicon wafers

    Science.gov (United States)

    Pizzolato, Marco; Masserey, Bernard; Robyr, Jean-Luc; Fromme, Paul

    2017-04-01

    Monocrystalline silicon wafers are widely used in the photovoltaic industry for solar panels with high conversion efficiency. The cutting process can introduce micro-cracks in the thin wafers and lead to varying thickness. High frequency guided ultrasonic waves are considered for the structural monitoring of the wafers. The anisotropy of the monocrystalline silicon leads to variations of the wave characteristics, depending on the propagation direction relative to the crystal orientation. Full three-dimensional Finite Element simulations of the guided wave propagation were conducted to visualize and quantify these effects for a line source. The phase velocity (slowness) and skew angle of the two fundamental Lamb wave modes (first anti-symmetric mode A0 and first symmetric mode S0) for varying propagation directions relative to the crystal orientation were measured experimentally. Selective mode excitation was achieved using a contact piezoelectric transducer with a custom-made wedge and holder to achieve a controlled contact pressure. The out-of-plane component of the guided wave propagation was measured using a noncontact laser interferometer. Good agreement was found with the simulation results and theoretical predictions based on nominal material properties of the silicon wafer.

  17. Three-Dimensional Electromagnetic High Frequency Axisymmetric Cavity Scars.

    Energy Technology Data Exchange (ETDEWEB)

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt

    2014-10-01

    This report examines the localization of high frequency electromagnetic fi elds in three-dimensional axisymmetric cavities along periodic paths between opposing sides of the cavity. The cases where these orbits lead to unstable localized modes are known as scars. This report treats both the case where the opposing sides, or mirrors, are convex, where there are no interior foci, and the case where they are concave, leading to interior foci. The scalar problem is treated fi rst but the approximations required to treat the vector fi eld components are also examined. Particular att ention is focused on the normalization through the electromagnetic energy theorem. Both projections of the fi eld along the scarred orbit as well as point statistics are examined. Statistical comparisons are m ade with a numerical calculation of the scars run with an axisymmetric simulation. This axisymmetric cas eformstheoppositeextreme(wherethetwomirror radii at each end of the ray orbit are equal) from the two -dimensional solution examined previously (where one mirror radius is vastly di ff erent from the other). The enhancement of the fi eldontheorbitaxiscanbe larger here than in the two-dimensional case. Intentionally Left Blank

  18. Ultra high frequency induction welding of powder metal compacts

    Directory of Open Access Journals (Sweden)

    Çavdar, Uǧur

    2014-06-01

    Full Text Available The application of the iron based Powder Metal (PM compacts in Ultra High Frequency Induction Welding (UHFIW were reviewed. These PM compacts are used to produce cogs. This study investigates the methods of joining PM materials enforceability with UHFIW in the industry application. Maximum stress and maximum strain of welded PM compacts were determined by three point bending and strength tests. Microhardness and microstructure of induction welded compacts were determined.Soldadura por inducción de ultra alta frecuencia de polvos de metal compactados. Se ha realizado un estudio de la aplicación de polvos de metal (PM de base hierro compactados por soldadura por inducción de ultra alta frecuencia (UHFIW. Estos polvos de metal compactados se utilizan para producir engranajes. Este estudio investiga los métodos de uni.n de los materiales de PM con UHFIW en su aplicación en la industria. La máxima tensión y la máxima deformación de los polvos de metal compactados soldados fueron determinadas por flexión en tres puntos y prueba de resistencia. Se determinó la microdureza y la microestructura de los polvos compactados por soldadura por inducción.

  19. Breast tissue characterization with high-frequency scanning acoustic microscopy

    Science.gov (United States)

    Kumon, R. E.; Bruno, I.; Heartwell, B.; Maeva, E.

    2004-05-01

    We have performed imaging of breast tissue using scanning acoustic microscopy (SAM) in the range of 25-50 MHz with the goal of accurately and rapidly determining the structure and composition throughout the volume of the samples. In contrast to traditional histological slides, SAM images can be obtained without special preparation, sometimes even without sectioning, but with sufficiently high spatial resolution to give information comparable to surface optical images. As a result, the use of high-frequency SAM at the time of breast lumpectomy to identify disease-free margins has the potential to reduce reoperative rates, patient anxiety, and local recurrence. However, only limited work has been performed to characterize breast tissue in the frequency range above clinical ultrasound devices. The samples are 4-cm2-thick sections (2-3 mm) taken from mastectomies and preserved in formalin. They are placed between two plates and immersed in water during imaging. Attenuation images are acquired by focusing the acoustic beam at the top and bottom of the samples, although better results were obtained for bottom focusing. For purposes of comparison and identification of histological features, acoustical images will be presented along with optical images obtained from the same samples. [Work supported by CIHR.

  20. Challenges in graphene integration for high-frequency electronics

    Science.gov (United States)

    Giannazzo, F.; Fisichella, G.; Greco, G.; Roccaforte, F.

    2016-06-01

    This paper provides an overview of the state-of-the-art research on graphene (Gr) for high-frequency (RF) devices. After discussing current limitations of lateral Gr RF transistors, novel vertical devices concepts such as the Gr Base Hot Electron Transistor (GBHET) will be introduced and the main challenges in Gr integration within these architectures will be discussed. In particular, a GBHET device based on Gr/AlGaN/GaN heterostructure will be considered. An approach to the fabrication of this heterostructure by transfer of CVD grown Gr on copper to the AlGaN surface will be presented. The morphological and electrical properties of this system have been investigated at nanoscale by atomic force microscopy (AFM) and conductive atomic force microscopy (CAFM). In particular, local current-voltage measurements by the CAFM probe revealed the formation of a Schottky contact with low barrier height (˜0.41 eV) and excellent lateral uniformity between Gr and AlGaN. Basing on the electrical parameters extracted from this characterization, the theoretical performances of a GBHET formed by a metal/Al2O3/Gr/AlGaN/GaN stack have been evaluated.

  1. High-frequency instability of the sheath-plasma resonance

    Science.gov (United States)

    Stenzel, R. L.

    1989-01-01

    Coherent high frequency oscillations near the electron plasma frequency (omega approx. less than omega sub p) are generated by electrodes with positive dc bias immersed in a uniform Maxwellian afterglow plasma. The instability occurs at the sheath-plasma resonance and is driven by a negative RF sheath resistance associated with the electron inertia in the diode-like electron-rich sheath. With increasing dc bias, i.e., electron transit time, the instability exhibits a hard threshold, downward frequency pulling, line broadening and copious harmonics. The fundamental instability is a bounded oscillation due to wave evanescence, but the harmonics are radiated as electromagnetic waves from the electrodes acting like antennas. Wavelength and polarization measurements confirm the emission process. Electromagnetic waves are excited by electrodes of various geometries (planes, cylinders, spheres) which excludes other radiation mechanisms such as orbitrons or beam-plasma instabilities. The line broadening mechanism was identified as a frequency modulation via the electron transit time by dynamic ions. Ion oscillations at the sheath edge give rise to burst-like RF emissions. These laboratory observations of a new instability are important for antennas in space plasmas, generation of coherent beams with diodes, and plasma diagnostics.

  2. Theory of High Frequency Rectification by Silicon Crystals

    Science.gov (United States)

    Bethe, H. A.

    1942-10-29

    The excellent performance of British "red dot" crystals is explained as due to the knife edge contact against a polished surface. High frequency rectification depends critically on the capacity of the rectifying boundary layer of the crystal, C. For high conversion efficiency, the product of this capacity and of the "forward" (bulk) resistance R {sub b} of the crystal must be small. For a knife edge, this product depends primarily on the breadth of the knife edge and very little upon its length. The contact can therefore have a rather large area which prevents burn-out. For a wavelength of 10 cm. the computations show that the breadth of the knife edge should be less than about 10 {sup -3} cm. For a point contact the radius must be less than 1.5 x 10 {sup -3} cm. and the resulting small area is conducive to burn-out. The effect of "tapping" is probably to reduce the area of contact. (auth)

  3. High-frequency ultrasonic arrays for ocular imaging

    Science.gov (United States)

    Jaeger, M. D.; Kline-Schoder, R. J.; Douville, G. M.; Gagne, J. R.; Morrison, K. T.; Audette, W. E.; Kynor, D. B.

    2007-03-01

    High-resolution ultrasound imaging of the anterior portion of the eye has been shown to provide important information for sizing of intraocular lens implants, diagnosis of pathological conditions, and creation of detailed maps of corneal topography to guide refractive surgery. Current ultrasound imaging systems rely on mechanical scanning of a single acoustic element over the surface of the eye to create the three-dimensional information needed by clinicians. This mechanical scanning process is time-consuming and subject to errors caused by eye movement during the scanning period. This paper describes development of linear ultrasound imaging arrays intended to increase the speed of image acquisition and reduce problems associated with ocular motion. The arrays consist of a linear arrangement of high-frequency transducer elements designed to operate in the 50 - 75 MHz frequency range. The arrays are produced using single-crystal lithium niobate piezoelectric material, thin film electrodes, and epoxy-based acoustic layers. The array elements have been used to image steel test structures and bovine cornea.

  4. High Frequency Vibration Based Fatigue Testing of Developmental Alloys

    Science.gov (United States)

    Holycross, Casey M.; Srinivasan, Raghavan; George, Tommy J.; Tamirisakandala, Seshacharyulu; Russ, Stephan M.

    Many fatigue test methods have been previously developed to rapidly evaluate fatigue behavior. This increased test speed can come at some expense, since these methods may require non-standard specimen geometry or increased facility and equipment capability. One such method, developed by George et al, involves a base-excited plate specimen driven into a high frequency bending resonant mode. This resonant mode is of sufficient frequency (typically 1200 to 1700 Hertz) to accumulate 107 cycles in a few hours. One of the main limitations of this test method is that fatigue cracking is almost certainly guaranteed to be surface initiated at regions of high stress. This brings into question the validity of the fatigue test results, as compared to more traditional uniaxial, smooth-bar testing, since high stresses are subjecting only a small volume to fatigue damage. This limitation also brings into question the suitability of this method to screen developmental alloys, should their initiation life be governed by subsurface flaws. However, if applicable, the rapid generation of fatigue data using this method would facilitate faster design iterations, identifying more quickly, material and manufacturing process deficiencies. The developmental alloy used in this study was a powder metallurgy boron-modified Ti-6Al-4V, a new alloy currently being considered for gas turbine engine fan blades. Plate specimens were subjected to fully reversed bending fatigue. Results are compared with existing data from commercially available Ti-6Al-4V using both vibration based and more traditional fatigue test methods.

  5. Refractivity variations and propagation at Ultra High Frequency

    Science.gov (United States)

    Alam, I.; Najam-Ul-Islam, M.; Mujahid, U.; Shah, S. A. A.; Ul Haq, Rizwan

    Present framework is established to deal with the refractivity variations normally affected the radio waves propagation at different frequencies, ranges and different environments. To deal such kind of effects, many researchers proposed several methodologies. One method is to use the parameters from meteorology to investigate these effects of variations in refractivity on propagation. These variations are region specific and we have selected a region of one kilometer height over the English Channel. We have constructed different modified refractivity profiles based on the local meteorological data. We have recorded more than 48 million received signal strength from a communication links of 50 km operating at 2015 MHz in the Ultra High Frequency band giving path loss between transmitting and receiving stations of the experimental setup. We have used parabolic wave equation method to simulate an hourly value of signal strength and compared the obtained simulated loss to the experimental loss. The analysis is made to compute refractivity distribution of standard (STD) and ITU (International Telecommunication Union) refractivity profiles for various evaporation ducts. It is found that a standard refractivity profile is better than the ITU refractivity profiles for the region at 2015 MHz. Further, it is inferred from the analysis of results that 10 m evaporation duct height is the dominant among all evaporation duct heights considered in the research.

  6. Improving NASICON Sinterability through Crystallization under High Frequency Electrical Fields

    Directory of Open Access Journals (Sweden)

    Ilya eLisenker

    2016-03-01

    Full Text Available The effect of high frequency (HF electric fields on the crystallization and sintering rates of a lithium aluminum germanium phosphate (LAGP ion conducting ceramic was investigated. LAGP with the nominal composition Li1.5Al0.5Ge1.5(PO43 was crystallized and sintered, both conventionally and under effect of electrical field. Electrical field application, of 300V/cm at 1MHz, produced up to a 40% improvement in sintering rate of LAGP that was crystallized and sintered under the HF field. Heat sink effect of the electrodes appears to arrest thermal runaway and subsequent flash behavior. Sintered pellets were characterized using XRD, SEM, TEM and EIS to compare conventionally and field sintered processes. The as-sintered structure appears largely unaffected by the field as the sintering curves tend to converge beyond initial stages of sintering. Differences in densities and microstructure after 1 hour of sintering were minor with measured sintering strains of 31% vs. 26% with and without field, respectively . Ionic conductivity of the sintered pellets was evaluated and no deterioration due to the use of HF field was noted, though capacitance of grain boundaries due to secondary phases was significantly increased.

  7. Refraction of high frequency noise in an arbitrary jet flow

    Science.gov (United States)

    Khavaran, Abbas; Krejsa, Eugene A.

    1994-01-01

    Refraction of high frequency noise by mean flow gradients in a jet is studied using the ray-tracing methods of geometrical acoustics. Both the two-dimensional (2D) and three-dimensional (3D) formulations are considered. In the former case, the mean flow is assumed parallel and the governing propagation equations are described by a system of four first order ordinary differential equations. The 3D formulation, on the other hand, accounts for the jet spreading as well as the axial flow development. In this case, a system of six first order differential equations are solved to trace a ray from its source location to an observer in the far field. For subsonic jets with a small spreading angle both methods lead to similar results outside the zone of silence. However, with increasing jet speed the two prediction models diverge to the point where the parallel flow assumption is no longer justified. The Doppler factor of supersonic jets as influenced by the refraction effects is discussed and compared with the conventional modified Doppler factor.

  8. Bottomside Ionospheric Electron Density Specification using Passive High Frequency Signals

    Science.gov (United States)

    Kaeppler, S. R.; Cosgrove, R. B.; Mackay, C.; Varney, R. H.; Kendall, E. A.; Nicolls, M. J.

    2016-12-01

    The vertical bottomside electron density profile is influenced by a variety of natural sources, most especially traveling ionospheric disturbances (TIDs). These disturbances cause plasma to be moved up or down along the local geomagnetic field and can strongly impact the propagation of high frequency radio waves. While the basic physics of these perturbations has been well studied, practical bottomside models are not well developed. We present initial results from an assimilative bottomside ionosphere model. This model uses empirical orthogonal functions based on the International Reference Ionosphere (IRI) to develop a vertical electron density profile, and features a builtin HF ray tracing function. This parameterized model is then perturbed to model electron density perturbations associated with TIDs or ionospheric gradients. Using the ray tracing feature, the model assimilates angle of arrival measurements from passive HF transmitters. We demonstrate the effectiveness of the model using angle of arrival data. Modeling results of bottomside electron density specification are compared against suitable ancillary observations to quantify accuracy of our model.

  9. Non-invasive high-frequency vascular ultrasound elastography

    Energy Technology Data Exchange (ETDEWEB)

    Maurice, Roch L [Laboratory of Biorheology and Medical Ultrasonics, Research Center, University of Montreal Hospital, Quebec (Canada); Daronat, Michel [Laboratory of Biorheology and Medical Ultrasonics, Research Center, University of Montreal Hospital, Quebec (Canada); Ohayon, Jacques [Laboratory TIMC-IMAG, UMR CNRS 5525, Institut A. Bonniot, 38706 La Tronche (France); Stoyanova, Ekatherina [Laboratory of Biorheology and Medical Ultrasonics, Research Center, University of Montreal Hospital, Quebec (Canada); Foster, F Stuart [Department of Medical Biophysics, Sunnybrook and Women' s College Health Sciences Centre, University of Toronto, Ontario (Canada); Cloutier, Guy [Laboratory of Biorheology and Medical Ultrasonics, Research Center, University of Montreal Hospital, Quebec (Canada); Department of Radiology, Radio-oncology and Nuclear Medicine, University of Montreal, Quebec (Canada)

    2005-04-07

    Non-invasive vascular elastography (NIVE) was recently introduced to characterize mechanical properties of superficial arteries. In this paper, the feasibility of NIVE and its applicability in the context of high-frequency ultrasound imaging is investigated. First, experiments were performed in vitro on vessel-mimicking phantoms. Polyvinyl alcohol cryogel was used to create two double-layer vessels with different mechanical properties. In both cases, the stiffness of the inner layer was made softer. Radial stress was applied within the lumen of the phantoms by applying incremental static pressure steps with a column of a flowing mixture of water-glycerol. The vessel phantoms were insonified at 32 MHz with an ultrasound biomicroscope to provide cross-section sequences of radio-frequency (RF) ultrasound data. The Lagrangian speckle model estimator (LSME) was used to assess the two-dimensional-strain tensors, and the composite Von Mises elastograms were computed. A new implementation of the LSME based on the optical flow equations was introduced. Deformation parameters were estimated using an inversion algorithm. For each in vitro experiment, both layers of approximately 1 mm were distinguished. Second, the use of the method for the purpose of studying small vessels (MicroNIVE) in genetically engineered rodents was introduced. Longitudinal scans of the carotid artery were performed at 40 MHz. The in vivo results give confidence in the feasibility of MicroNIVE as a potential tool to non-invasively study the impact of targeted genes on vascular remodelling in rodents.

  10. Mechanisms and factors that influence high frequency retroviral recombination

    DEFF Research Database (Denmark)

    Delviks-Frankenberry, Krista; Galli, Andrea; Nikolaitchik, Olga

    2011-01-01

    With constantly changing environmental selection pressures, retroviruses rely upon recombination to reassort polymorphisms in their genomes and increase genetic diversity, which improves the chances for the survival of their population. Recombination occurs during DNA synthesis, whereby reverse...... transcriptase undergoes template switching events between the two copackaged RNAs, resulting in a viral recombinant with portions of the genetic information from each parental RNA. This review summarizes our current understanding of the factors and mechanisms influencing retroviral recombination, fidelity...... of the recombination process, and evaluates the subsequent viral diversity and fitness of the progeny recombinant. Specifically, the high mutation rates and high recombination frequencies of HIV-1 will be analyzed for their roles in influencing HIV-1 global diversity, as well as HIV-1 diagnosis, drug treatment...

  11. High frequency of the HRAS oncogene codon 12 mutation in Macedonian patients with urinary bladder cancer

    Directory of Open Access Journals (Sweden)

    Sasho Panov

    2004-01-01

    Full Text Available Point mutations at codon 12 of the HRAS (v-Ha-ras Harvey rat sarcoma viral oncogene homolog oncogene are one of the best defined and widely studied molecular genetic events in transitional cell carcinoma (TCC of the urinary bladder. The aim of this study was to use the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP analysis of paraffin-embedded tissue-derived DNA to determine the frequency of the HRAS oncogene G ->T codon 12 mutation in TCC patients being treated at the University Urology Clinic in Skopje, Republic of Macedonia. DNA isolated from paraffin-embedded tissue (PET surgically removed TCC specimens of 62 (81.58% out of 76 patients were successfully amplified, the remaining 14 (18.42% showing compromised DNA integrity. The codon 12 mutation of the HRAS oncogene was found in 24 (38.71% out of 62 successfully tested TCC urinary bladder samples. No significant relationship between the mutation frequency and the histopathological grade of tumor differentiation was detected (chi² = 0.044; p = 0.978. The relatively high frequency of mutations found in our study was comparable with some of the previously reported data obtained by this and/or other PCR-based methods. This highly sensitive and specific PCR-RFLP analysis was demonstrated to be a suitable method for the detection of mutations at codon 12 of the HRAS oncogene in PET samples of urinary bladder TCC.

  12. Ultrastructural Study of Alveolar Epithelial Type II Cells by High-Frequency Oscillatory Ventilation

    Directory of Open Access Journals (Sweden)

    Xiaofei Qin

    2013-01-01

    Full Text Available Alveolar epithelial type II cells (AECIIs containing lamellar bodies (LBs are alveolar epithelial stem cells that have important functions in the repair of lung structure and function after lung injury. The ultrastructural changes in AECIIs after high-frequency oscillatory ventilation (HFOV with a high lung volume strategy or conventional ventilation were evaluated in a newborn piglet model with acute lung injury (ALI. After ALI with saline lavage, newborn piglets were randomly assigned into five study groups (three piglets in each group, namely, control (no mechanical ventilation, conventional ventilation for 24 h, conventional ventilation for 48 h, HFOV for 24 h, and HFOV for 48 h. The lower tissues of the right lung were obtained to observe the AECII ultrastructure. AECIIs with reduced numbers of microvilli, decreased LBs electron density, and vacuole-like LBs deformity were commonly observed in all five groups. Compared with conventional ventilation groups, the decrease in numbers of microvilli and LBs electron density, as well as LBs with vacuole-like appearance and polymorphic deformity, was less severe in HFOV with high lung volume strategy groups. AECIIs were injured during mechanical ventilation. HFOV with a high lung volume strategy resulted in less AECII damage than conventional ventilation.

  13. Exon 3-deleted/full-length growth hormone receptor polymorphism genotype frequencies in Spanish short small-for-gestational-age (SGA) children and adolescents (n = 247) and in an adult control population (n = 289) show increased fl/fl in short SGA.

    Science.gov (United States)

    Audí, Laura; Esteban, Cristina; Carrascosa, Antonio; Espadero, Rosa; Pérez-Arroyo, Annalisa; Arjona, Rosa; Clemente, María; Wollmann, Hartmut; Fryklund, Linda; Parodi, Luis A

    2006-12-01

    A polymorphism in the human GH receptor gene (d3/fl-GHR) resulting in genomic deletion of exon 3 has been associated with the degree of height increase in response to GH therapy. The objective of the study was to evaluate the frequencies of d3/fl-GHR polymorphism genotypes in control and short small-for-gestational-age (SGA) populations. An adult control population with heights normally distributed (ACPNH) between -2 and +2 sd score (SDS) and a short non-GH-deficient SGA child population were selected. Thirty Spanish hospitals participated in the selection of the short non-GH-deficient SGA children in the setting of a controlled, randomized trial, and one of these hospitals selected the ACPNH. CONTROLS AND PATIENTS: Two hundred eighty-nine adult subjects of both sexes constituted the ACPNH and 247 children and adolescents of both sexes the short SGA patients. Heights and weights were recorded in the ACPNH, and auxologic and biochemical data were recorded at each hospital for the SGA patients; d3/fl-GHR genotypes were determined and data analyzed in a single hospital. In short SGA patients, d3/fl-GHR genotype frequencies were significantly different from those in ACPNH, with a higher frequency of fl/fl genotype (P or=-2 SDS, n = 60). Our data showed significant differences in the frequency distribution of the d3/fl-GHR genotypes between a normally distributed adult height population and short SGA children, with the biologically less active fl/fl genotype being almost twice as frequent in SGA patients. These data suggest that the d3/fl-GHR polymorphism might be considered among the factors that contribute to the phenotypic expression of growth.

  14. A New High Frequency Injection Method Based on Duty Cycle Shifting without Maximum Voltage Magnitude Loss

    DEFF Research Database (Denmark)

    Wang, Dong; Lu, Kaiyuan; Rasmussen, Peter Omand

    2015-01-01

    The conventional high frequency signal injection method is to superimpose a high frequency voltage signal to the commanded stator voltage before space vector modulation. Therefore, the magnitude of the voltage used for machine torque production is limited. In this paper, a new high frequency...

  15. High-frequency TRNS reduces BOLD activity during visuomotor learning.

    Directory of Open Access Journals (Sweden)

    Catarina Saiote

    Full Text Available Transcranial direct current stimulation (tDCS and transcranial random noise stimulation (tRNS consist in the application of electrical current of small intensity through the scalp, able to modulate perceptual and motor learning, probably by changing brain excitability. We investigated the effects of these transcranial electrical stimulation techniques in the early and later stages of visuomotor learning, as well as associated brain activity changes using functional magnetic resonance imaging (fMRI. We applied anodal and cathodal tDCS, low-frequency and high-frequency tRNS (lf-tRNS, 0.1-100 Hz; hf-tRNS 101-640 Hz, respectively and sham stimulation over the primary motor cortex (M1 during the first 10 minutes of a visuomotor learning paradigm and measured performance changes for 20 minutes after stimulation ceased. Functional imaging scans were acquired throughout the whole experiment. Cathodal tDCS and hf-tRNS showed a tendency to improve and lf-tRNS to hinder early learning during stimulation, an effect that remained for 20 minutes after cessation of stimulation in the late learning phase. Motor learning-related activity decreased in several regions as reported previously, however, there was no significant modulation of brain activity by tDCS. In opposition to this, hf-tRNS was associated with reduced motor task-related-activity bilaterally in the frontal cortex and precuneous, probably due to interaction with ongoing neuronal oscillations. This result highlights the potential of lf-tRNS and hf-tRNS to differentially modulate visuomotor learning and advances our knowledge on neuroplasticity induction approaches combined with functional imaging methods.

  16. Lead extraction experience with high frequency excimer laser.

    Science.gov (United States)

    Tanawuttiwat, Tanyanan; Gallego, Daniel; Carrillo, Roger G

    2014-09-01

    A higher frequency Excimer laser sheath using an 80-Hz pulse repetitive rate was approved by the Food and Drug Administration in April 2012. We reported our initial clinical experience with a high-frequency Excimer laser sheath and compared it with lower-frequency laser sheaths which have been previously used. In this single center, retrospective cohort study, we evaluated patients who underwent lead extraction from December 2008 to May 2013. Those who underwent lead removal without using a laser sheath or with approaches other than subclavian were excluded. Primary endpoints included total laser time, number of pulses, and complications. Data on clinical characteristics, lead type, indications, and outcomes were prospectively collected and analyzed. A total of 427 patients were included in the study (72.6% male; age 67.9 ± 15.23 years). Lower frequency and higher frequency laser sheaths were used in 315 and 112 patients, respectively. A total of 821 leads were removed with 765 leads (93.2%) extracted using the Excimer laser sheath. Lead age was 5.71 ± 4.96 years. Complete extraction was seen in all patients. A higher-frequency laser sheath was associated with a lower laser time and a lower total number of laser pulses even after adjustments for the number of leads, type of leads, and lead age. In the higher frequency group, mortality rate was 0.9% and minor complication rate was 3.6%. When compared with the lower-frequency laser sheath, the higher-frequency laser sheath requires less laser times and more efficient amount of pulses for lead extraction with comparable success rate. Due to the rarity of major and minor complications, no statistical significance was found between the two groups. ©2014 Wiley Periodicals, Inc.

  17. Achieving High-Frequency Optical Control of Synaptic Transmission

    Science.gov (United States)

    Jackman, Skyler L.; Beneduce, Brandon M.; Drew, Iain R.

    2014-01-01

    The optogenetic tool channelrhodopsin-2 (ChR2) is widely used to excite neurons to study neural circuits. Previous optogenetic studies of synapses suggest that light-evoked synaptic responses often exhibit artificial synaptic depression, which has been attributed to either the inability of ChR2 to reliably fire presynaptic axons or to ChR2 elevating the probability of release by depolarizing presynaptic boutons. Here, we compare light-evoked and electrically evoked synaptic responses for high-frequency stimulation at three synapses in the mouse brain. At synapses from Purkinje cells to deep cerebellar nuclei neurons (PC→DCN), light- and electrically evoked synaptic currents were remarkably similar for ChR2 expressed transgenically or with adeno-associated virus (AAV) expression vectors. For hippocampal CA3→CA1 synapses, AAV expression vectors of serotype 1, 5, and 8 led to light-evoked synaptic currents that depressed much more than electrically evoked currents, even though ChR2 could fire axons reliably at up to 50 Hz. The disparity between optical and electrical stimulation was eliminated when ChR2 was expressed transgenically or with AAV9. For cerebellar granule cell to stellate cell (grc→SC) synapses, AAV1 also led to artificial synaptic depression and AAV9 provided superior performance. Artificial synaptic depression also occurred when stimulating over presynaptic boutons, rather than axons, at CA3→CA1 synapses, but not at PC→DCN synapses. These findings indicate that ChR2 expression methods and light stimulation techniques influence synaptic responses in a neuron-specific manner. They also identify pitfalls associated with using ChR2 to study synapses and suggest an approach that allows optogenetics to be applied in a manner that helps to avoid potential complications. PMID:24872574

  18. Tsunami Arrival Detection with High Frequency (HF Radar

    Directory of Open Access Journals (Sweden)

    Donald Barrick

    2012-05-01

    Full Text Available Quantitative real-time observations of a tsunami have been limited to deep-water, pressure-sensor observations of changes in the sea surface elevation and observations of sea level fluctuations at the coast, which are essentially point measurements. Constrained by these data, models have been used for predictions and warning of the arrival of a tsunami, but to date no system exists for local detection of an actual incoming wave with a significant warning capability. Networks of coastal high frequency (HF-radars are now routinely observing surface currents in many countries. We report here on an empirical method for the detection of the initial arrival of a tsunami, and demonstrate its use with results from data measured by fourteen HF radar sites in Japan and USA following the magnitude 9.0 earthquake off Sendai, Japan, on 11 March 2011. The distance offshore at which the tsunami can be detected, and hence the warning time provided, depends on the bathymetry: the wider the shallow continental shelf, the greater this time. We compare arrival times at the radars with those measured by neighboring tide gauges. Arrival times measured by the radars preceded those at neighboring tide gauges by an average of 19 min (Japan and 15 min (USA The initial water-height increase due to the tsunami as measured by the tide gauges was moderate, ranging from 0.3 to 2 m. Thus it appears possible to detect even moderate tsunamis using this method. Larger tsunamis could obviously be detected further from the coast. We find that tsunami arrival within the radar coverage area can be announced 8 min (i.e., twice the radar spectral time resolution after its first appearance. This can provide advance warning of the tsunami approach to the coastline locations.

  19. Very high frequency plasma reactant for atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Il-Kwon; Yoo, Gilsang; Yoon, Chang Mo [School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, Tae Hyung; Yeom, Geun Young [Department of Advanced Materials Engineering, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Kim, Kangsik; Lee, Zonghoon [School Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919 (Korea, Republic of); Jung, Hanearl; Lee, Chang Wan [School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Kim, Hyungjun, E-mail: hyungjun@yonsei.ac.kr [School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Lee, Han-Bo-Ram, E-mail: hbrlee@inu.ac.kr [Department of Materials Science and Engineering, Incheon National University, 406-840 Incheon (Korea, Republic of)

    2016-11-30

    Highlights: • Fundamental research plasma process for thin film deposition is presented. • VHF plasma source for PE-ALD Al{sub 2}O{sub 3} was employed to reduce plasma damage. • The use of VHF plasma improved all of the film qualities and growth characteristics. - Abstract: Although plasma-enhanced atomic layer deposition (PE-ALD) results in several benefits in the formation of high-k dielectrics, including a low processing temperature and improved film properties compared to conventional thermal ALD, energetic radicals and ions in the plasma cause damage to layer stacks, leading to the deterioration of electrical properties. In this study, the growth characteristics and film properties of PE-ALD Al{sub 2}O{sub 3} were investigated using a very-high-frequency (VHF) plasma reactant. Because VHF plasma features a lower electron temperature and higher plasma density than conventional radio frequency (RF) plasma, it has a larger number of less energetic reaction species, such as radicals and ions. VHF PE-ALD Al{sub 2}O{sub 3} shows superior physical and electrical properties over RF PE-ALD Al{sub 2}O{sub 3}, including high growth per cycle, excellent conformality, low roughness, high dielectric constant, low leakage current, and low interface trap density. In addition, interlayer-free Al{sub 2}O{sub 3} on Si was achieved in VHF PE-ALD via a significant reduction in plasma damage. VHF PE-ALD will be an essential process to realize nanoscale devices that require precise control of interfaces and electrical properties.

  20. Robust Optimization Design Algorithm for High-Frequency TWTs

    Science.gov (United States)

    Wilson, Jeffrey D.; Chevalier, Christine T.

    2010-01-01

    Traveling-wave tubes (TWTs), such as the Ka-band (26-GHz) model recently developed for the Lunar Reconnaissance Orbiter, are essential as communication amplifiers in spacecraft for virtually all near- and deep-space missions. This innovation is a computational design algorithm that, for the first time, optimizes the efficiency and output power of a TWT while taking into account the effects of dimensional tolerance variations. Because they are primary power consumers and power generation is very expensive in space, much effort has been exerted over the last 30 years to increase the power efficiency of TWTs. However, at frequencies higher than about 60 GHz, efficiencies of TWTs are still quite low. A major reason is that at higher frequencies, dimensional tolerance variations from conventional micromachining techniques become relatively large with respect to the circuit dimensions. When this is the case, conventional design- optimization procedures, which ignore dimensional variations, provide inaccurate designs for which the actual amplifier performance substantially under-performs that of the design. Thus, this new, robust TWT optimization design algorithm was created to take account of and ameliorate the deleterious effects of dimensional variations and to increase efficiency, power, and yield of high-frequency TWTs. This design algorithm can help extend the use of TWTs into the terahertz frequency regime of 300-3000 GHz. Currently, these frequencies are under-utilized because of the lack of efficient amplifiers, thus this regime is known as the "terahertz gap." The development of an efficient terahertz TWT amplifier could enable breakthrough applications in space science molecular spectroscopy, remote sensing, nondestructive testing, high-resolution "through-the-wall" imaging, biomedical imaging, and detection of explosives and toxic biochemical agents.

  1. High-frequency oscillations (HFOs) in clinical epilepsy

    Science.gov (United States)

    Jacobs, J.; Staba, R.; Asano, E.; Otsubo, H.; Wu, J.Y.; Zijlmans, M.; Mohamed, I.; Kahane, P.; Dubeau, F.; Navarro, V.; Gotman, J.

    2013-01-01

    Epilepsy is one of the most frequent neurological diseases. In focal medically refractory epilepsies, successful surgical treatment largely depends on the identification of epileptogenic zone. High-frequency oscillations (HFOs) between 80 and 500 Hz, which can be recorded with EEG, may be novel markers of the epileptogenic zone. This review discusses the clinical importance of HFOs as markers of epileptogenicity and their application in different types of epilepsies. HFOs are clearly linked to the seizure onset zone, and the surgical removal of regions generating them correlates with a seizure free post-surgical outcome. Moreover, HFOs reflect the seizure-generating capability of the underlying tissue, since they are more frequent after the reduction of antiepileptic drugs. They can be successfully used in pediatric epilepsies such as epileptic spasms and help to understand the generation of this specific type of seizures. While mostly recorded on intracranial EEGs, new studies suggest that identification of HFOs on scalp EEG or magnetoencephalography (MEG) is possible as well. Thus not only patients with refractory epilepsies and invasive recordings but all patients might profit from the analysis of HFOs. Despite these promising results, the analysis of HFOs is not a routine clinical procedure; most results are derived from relatively small cohorts of patients and many aspects are not yet fully understood. Thus the review concludes that even if HFOs are promising biomarkers of epileptic tissue, there are still uncertainties about mechanisms of generation, methods of analysis, and clinical applicability. Large multicenter prospective studies are needed prior to widespread clinical application. PMID:22480752

  2. Low and High-Frequency Field Potentials of Cortical Networks ...

    Science.gov (United States)

    Neural networks grown on microelectrode arrays (MEAs) have become an important, high content in vitro assay for assessing neuronal function. MEA experiments typically examine high- frequency (HF) (>200 Hz) spikes, and bursts which can be used to discriminate between different pharmacological agents/chemicals. However, normal brain activity is additionally composed of integrated low-frequency (0.5-100 Hz) field potentials (LFPs) which are filtered out of MEA recordings. The objective of this study was to characterize the relationship between HF and LFP neural network signals, and to assess the relative sensitivity of LFPs to selected neurotoxicants. Rat primary cortical cultures were grown on glass, single-well MEA chips. Spontaneous activity was sampled at 25 kHz and recorded (5 min) (Multi-Channel Systems) from mature networks (14 days in vitro). HF (spike, mean firing rate, MFR) and LF (power spectrum, amplitude) components were extracted from each network and served as its baseline (BL). Next, each chip was treated with either 1) a positive control, bicuculline (BIC, 25μM) or domoic acid (DA, 0.3μM), 2) or a negative control, acetaminophen (ACE, 100μM) or glyphosate (GLY, 100μM), 3) a solvent control (H2O or DMSO:EtOH), or 4) a neurotoxicant, (carbaryl, CAR 5, 30μM ; lindane, LIN 1, 10μM; permethrin, PERM 25, 50μM; triadimefon, TRI 5, 65μM). Post treatment, 5 mins of spontaneous activity was recorded and analyzed. As expected posit

  3. National High Frequency Radar Network (hfrnet) and Pacific Research Efforts

    Science.gov (United States)

    Hazard, L.; Terrill, E. J.; Cook, T.; de Paolo, T.; Otero, M. P.; Rogowski, P.; Schramek, T. A.

    2016-12-01

    The U.S. High Frequency Radar Network (HFRNet) has been in operation for over ten years with representation from 31 organizations spanning academic institutions, state and local government agencies, and private organizations. HFRNet currently holds a collection from over 130 radar installations totaling over 10 million records of surface ocean velocity measurements. HFRNet is a primary example of inter-agency and inter-institutional partnerships for improving oceanographic research and operations. HF radar derived surface currents have been used in several societal applications including coastal search and rescue, oil spill response, water quality monitoring and marine navigation. Central to the operational success of the large scale network is an efficient data management, storage, access, and delivery system. The networking of surface current mapping systems is characterized by a tiered structure that extends from the individual field installations to local regional operations maintaining multiple sites and on to centralized locations aggregating data from all regions. The data system development effort focuses on building robust data communications from remote field locations (sites) for ingestion into the data system via data on-ramps (Portals or Site Aggregators) to centralized data repositories (Nodes). Centralized surface current data enables the aggregation of national surface current grids and allows for ingestion into displays, management tools, and models. The Coastal Observing Research and Development Center has been involved in international relationships and research in the Philippines, Palau, and Vietnam. CORDC extends this IT architecture of surface current mapping data systems leveraging existing developments and furthering standardization of data services for seamless integration of higher level applications. Collaborations include the Philippine Atmospheric Geophysical and Astronomical Services Administration (PAGASA), The Coral Reef Research

  4. Exposure to high-frequency transient electromagnetic fields.

    Science.gov (United States)

    Skotte, J H

    1996-02-01

    The purpose of this study was to assess exposure to high-frequency transient (HFT) electromagnetic fields in occupational and residential environments. Exposure to HFT electromagnetic fields was measured with personal dosimeters for 301 volunteers (396 measurements) in periods of 24 h in both occupational and residential environments. The study included electrical utility workers (generation, transmission, distribution, substation), office and industrial workers, and people living near high-power transmission lines. The measure of exposure to HFT fields was specified as the proportion of time (parts per million) in which the electric field exceeds a nominal threshold level of 200 V.m-1 at 5-20 MHz. Recently the specification of the HFT channel of the dosimeter has been found to be incomplete; therefore a testing of the threshold level and the sensitivity to electromagnetic fields from radio-telephones was carried out. The percentage of measurements with a mean workday exposure above 0.1 ppm was 6.5-9.4% for the utility groups and 0.9% for all the nonwork measurements. It is likely that the use of radio-telephones has contributed significantly to the number of HFT events in some of the measurements, especially for the generation workers. The nominal threshold level of the dosimeter was found to vary considerably depending on the polarization of the field (20-400 V.m-1 at 13.56 MHz for one instrument). Generally speaking, HFT fields appeared infrequently. The workday exposure to HFT fields and 50 Hz magnetic fields ranked the groups differently. There is a need for developing instrumentation for HFT field measurements further.

  5. Achieving high-frequency optical control of synaptic transmission.

    Science.gov (United States)

    Jackman, Skyler L; Beneduce, Brandon M; Drew, Iain R; Regehr, Wade G

    2014-05-28

    The optogenetic tool channelrhodopsin-2 (ChR2) is widely used to excite neurons to study neural circuits. Previous optogenetic studies of synapses suggest that light-evoked synaptic responses often exhibit artificial synaptic depression, which has been attributed to either the inability of ChR2 to reliably fire presynaptic axons or to ChR2 elevating the probability of release by depolarizing presynaptic boutons. Here, we compare light-evoked and electrically evoked synaptic responses for high-frequency stimulation at three synapses in the mouse brain. At synapses from Purkinje cells to deep cerebellar nuclei neurons (PC→DCN), light- and electrically evoked synaptic currents were remarkably similar for ChR2 expressed transgenically or with adeno-associated virus (AAV) expression vectors. For hippocampal CA3→CA1 synapses, AAV expression vectors of serotype 1, 5, and 8 led to light-evoked synaptic currents that depressed much more than electrically evoked currents, even though ChR2 could fire axons reliably at up to 50 Hz. The disparity between optical and electrical stimulation was eliminated when ChR2 was expressed transgenically or with AAV9. For cerebellar granule cell to stellate cell (grc→SC) synapses, AAV1 also led to artificial synaptic depression and AAV9 provided superior performance. Artificial synaptic depression also occurred when stimulating over presynaptic boutons, rather than axons, at CA3→CA1 synapses, but not at PC→DCN synapses. These findings indicate that ChR2 expression methods and light stimulation techniques influence synaptic responses in a neuron-specific manner. They also identify pitfalls associated with using ChR2 to study synapses and suggest an approach that allows optogenetics to be applied in a manner that helps to avoid potential complications. Copyright © 2014 the authors 0270-6474/14/347704-11$15.00/0.

  6. Allelic prevalence of intron 3 insertion/deletion genetic ...

    African Journals Online (AJOL)

    Leila Fallahzadeh-Abarghooei

    2015-03-18

    XRCC4; OMIM: 194363), plays an important role in repair of DNA double-strand breaks via non-homologous end joining pathway. In order to find the allelic prevalence of an insertion/deletion polymorphism in intron 3 of XRCC4 ...

  7. Allelic prevalence of intron 3 insertion/deletion genetic ...

    African Journals Online (AJOL)

    Allelic prevalence of intron 3 insertion/deletion genetic polymorphism of DNA double-strand break repair gene XRCC4 in four healthy Iranian populations. ... Conclusion: Although there is a significant heterogeneity between Iranian populations, the Del allele shows high prevalence among Iranian populations, which is ...

  8. Unbalanced heat isolation in high-frequency electrothermics of polymers

    Directory of Open Access Journals (Sweden)

    A. V. Livshits

    2014-01-01

    Full Text Available The polymeric materials are widely applied in many industries because they have a number of advantages, which allow their use instead of traditional materials. Nevertheless, the issues of manufacturing products from polymeric materials and their applications are insufficiently studied. The same can be said about high-frequency (HF electrothermics of polymers. Therefore, mathematical simulation of electrothermic processes is of interest both in terms of science and in terms of applications.Traditionally, the technological scheme with one insulator made of cardboard is used to implement the HF heating processes for welding of polymers without analyzing their insulating properties. For welding of polymer parts with various thickness it is interesting to consider the scheme with two heat insulators in the form of five-layer plate, including electrodes, insulators, and processed material. As a result of the conducted research activities the article presents a mathematical model in the form of a system of differential equations of unsteady heat conductivity taking into account internal sources of heat with appropriate boundary conditions, and software to implement it.The software that implements a mathematical model enables to study the mutual influence between the geometrical and electro-physical parameters of technological system of HF heating of the thermoplastics. From the calculations presented in numerical and graphic form the following areas of heating polymer are identified: uniform heating, regional zones of thermal influence of insulators.The article presents the research results of influence of heat insulators with different thickness on the distribution of thermoplastics temperature field. It is determined that the zone of maximum value of heating polymer can be displaced by modifying the parameters of insulating layers, thereby improving the welding quality of polymeric items.According to research results, we can conclude that there is a

  9. A Compact High Frequency Doppler Radio Scatterometer for Coastal Oceanography

    Science.gov (United States)

    Flament, P. J.; Harris, D.; Flament, M.; Fernandez, I. Q.; Hlivak, R.; Flores-vidal, X.; Marié, L.

    2016-12-01

    A low-power High Frequency Doppler Radar has been designed for large series production. The use of commercial-off-the-shelf components is maximized to minimize overall cost. Power consumption is reduced to 130W in full duty and 20W in stand-by under 20-36 V-DC, thus enabling solar/wind and/or fuel cell operation by default. For 8 channels, commercial components and sub-assemblies cost less than k20 excluding coaxial antenna cables, and less than four man-weeks of technician suffice for integration, testing and calibration, suggesting a final cost of about k36, based on production batches of 25 units. The instrument is integrated into passively-cooled 90x60x20 cm3 field-deployable enclosures, combining signal generation, transmitter, received, A/D converter and computer, alleviating the need for additional protection such as a container or building. It uses frequency-ramped continuous wave signals, and phased-array transmissions to decouple the direct path to the receivers. Five sub-assemblies are controlled by a Linux embedded computer: (i) direct digital synthesis of transmit and orthogonal local oscillator signals, derived from a low phase noise oven-controlled crystal; (ii) distributed power amplifiers totaling 5 W, integrated into λ/8 passive transmit antenna monopoles; (iii) λ/12 compact active receive antenna monopoles with embedded out-of-band rejection filters; (iv) analog receivers based on complex demodulation by double-balanced mixers, translating the HF spectrum to the audio band; (v) 24-bit analog-to-digital sigma-delta conversion at 12 kHz with 512x oversampling, followed by decimation to a final sampling frequency of 750 Hz. Except for the HF interference rejection filters, the electronics can operate between 3 and 50 MHz with no modification. At 13.5 MHz, 5 W transmit power, 15 min integration time, the high signal-to-noise ratio permits a typical range of 120 km for currents measurements with 8-antenna beam-forming. The University of Hawaii HFR

  10. Paternal origin of the de novo deleted chromosome 4 in Wolf-Hirschhorn syndrome.

    OpenAIRE

    Tupler, R.; Bortotto, L; Bühler, E M; Alkan, M; Malik, N J; Bösch-Al Jadooa, N; Memo, L; Maraschio, P

    1992-01-01

    The parental origin of the de novo deleted chromosome 4 was studied in five cases of Wolf-Hirschhorn syndrome using polymorphic probes mapping in the 4p16.3 region. In all the patients the deleted chromosome was found to be of paternal origin and these results, together with similar ones obtained by another group, make the preferential paternal origin of the de novo chromosome 4 deletion highly significant.

  11. High frequency acoustic propagation under variable sea surfaces

    Science.gov (United States)

    Senne, Joseph

    This dissertation examines the effects of rough sea surfaces and sub-surface bubbles on high frequency acoustic transmissions. Owing to the strong attenuation of electromagnetic waves in seawater, acoustic waves are used in the underwater realm much in the same way that electromagnetic waves are used in the atmosphere. The transmission and reception of acoustic waves in the underwater environment is important for a variety of fields including navigation, ocean observation, and real-time communications. Rough sea surfaces and sub-surface bubbles alter the acoustic signals that are received not only in the near-surface water column, but also at depth. This dissertation demonstrates that surface roughness and sub-surface bubbles notably affect acoustic transmissions with frequency ranges typical of underwater communications systems (10-50 kHz). The influence of rough surfaces on acoustic transmissions is determined by modeling forward propagation subject to sea surface dynamics that vary with time scales of less than a second to tens of seconds. A time-evolving rough sea surface model is combined with a rough surface formulation of a parabolic equation model for predicting time-varying acoustic fields. Linear surface waves are generated from surface wave spectra, and evolved in time using a Runge-Kutta integration technique. This evolving, range-dependent surface information is combined with other environmental parameters and fed into the acoustic model, giving an approximation of the time-varying acoustic field. The wide-angle parabolic equation model manages the rough sea surfaces by molding them into the boundary conditions for calculations of the near-surface acoustic field. The influence of sub-surface bubbles on acoustic transmissions is determined by modeling the population of bubbles near the surface and using those populations to approximate the effective changes in sound speed and attenuation. Both range-dependent and range-independent bubble models are

  12. Excitation and Ionisation dynamics in high-frequency plasmas

    Science.gov (United States)

    O'Connell, D.

    2008-07-01

    excitation and sustainment of the discharge. As the pressure decreases the discharge operates in so-called 'alpha-mode' where the sheath expansion is responsible for discharge sustainment. Decreasing the pressure towards the limit of operation (below 1 Pa) the discharge operates in a regime where kinetic effects dominate plasma sustainment. Wave particle interactions resulting from the flux of highly energetic electrons interacting with thermal bulk electrons give rise to a series of oscillations in the electron excitation phase space at the sheath edge. This instability is responsible for a significant energy deposit in the plasma when so-called 'ohmic heating' is no longer efficient. In addition to this an interesting electron acceleration mechanism occurs during the sheath collapse. The large sheath width, due to low plasma densities at the lower pressure, and electron inertia allows the build up of a local electric field accelerating electrons towards the electrode. Multi-frequency plasmas, provide additional process control for technological applications, and through investigating the excitation dynamics in such discharges the limitations of functional separation is observed. Non-linear frequency coupling is observed in plasma boundary sheaths governed by two frequencies simultaneously. In an alpha-operated discharge the sheath edge velocity governs the excitation and ionisation within the plasma, and it will be shown that this is determined by the time varying sheath width. The nature of the coupling effects strongly depends on the ratio of the applied voltages. Under technologically relevant conditions (low frequency voltage >> high frequency voltage) interesting phenomena depending on the phase relation of the voltages are also observed and will be discussed.

  13. Association between the DRD2-141C Insertion/Deletion polymorphism and schizophrenia Associação entre o polimorfismo -141C Ins/Del do gene do DRD2 e esquizofrenia

    Directory of Open Access Journals (Sweden)

    Quirino Cordeiro

    2009-06-01

    Full Text Available Epidemiological studies have demonstrated that the genetic component is an important risk factor for the development of schizophrenia. The genes that codify the different compounds of the dopaminergic system have created interest for molecular investigations in patients with schizophrenia because the antipsychotic drugs, especially those of first generation, act on this cerebral system. Thus the aim of the present study was to investigate the possible association between the -141 Ins/Del (rs1799732 polymorphism of the dopamine receptor type 2 (DRD2 and schizophrenia. The distribution of the alleles and genotypes of the studied polymorphism was investigated in a sample of 229 patients and 733 controls. There were statistical differences in the allelic (χ2=9.78; p=0.001 and genotypic genotypic (χ2=12.74; p=0.001 distributions between patients and controls. Thus the -141C Ins/Del polymorphism of the DRD2 gene (allele Ins was associated to the SCZ phenotype in the investigated sample.Estudos epidemiológicos têm demonstrado que o componente genético é um importante fator de risco para o desenvolvimento de esquizofrenia. Os genes que codificam os diferentes componentes do sistema dopaminérgico passaram a despertar interesse para os estudos moleculares em pacientes com esquizofrenia, devido ao fato dos antipsicóticos, em especial os de primeira geração, exercerem sua ação nesse sistema. Assim, o objetivo do presente estudo foi investigar a possível associação entre polimorfismo -141C Ins/Del (rs1799732 do gene do receptor dopaminérgico tipo 2 (DRD2 e esquizofrenia. Um total de 229 pacientes e 733 controles pareados para sexo e idade foi selecionado com o objetivo de investigar a distribuição dos alelos e genótipos do polimorfismo investigado entre os grupos de pacientes e controles. Houve diferença estatisticamente significante nas distribuições alélica (χ2=9,78; p=0,001 e genotípica (χ2=12,74; p=0,001 entre pacientes e

  14. Codon 201Gly Polymorphic Type of the DCC Gene is Related to Disseminated Neuroblastoma

    Directory of Open Access Journals (Sweden)

    Xiao-Tang Kong

    2001-01-01

    Full Text Available The deleted in colorectal carcinoma (DCC gene is a potential tumor- suppressor gene on chromosome 18821.3. The relatively high frequency of loss of heterozygosity (LOH and loss of expression of this gene in neuroblastoma, especially in the advanced stages, imply the possibility of involvement of the DCC gene in progression of neuroblastoma. However, only few typical mutations have been identified in this gene, indicating that other possible mechanisms for the inactivation of this gene may exist. A polymorphic change (Arg to Gly at DCC codon 201 is related to advanced colorectal carcinoma and increases in the tumors with absent DCC protein expression. In order to understand whether this change is associated with the development or progression of neuroblastoma, we investigated codon 201 polymorphism of the DCC gene in 102 primary neuroblastomas by polymerase chain reaction single-strand conformation polymorphism. We found no missense or nonsense mutations, but a polymorphic change from CGA (Arg to GGA (Gly at codon 201 resulting in three types of polymorphism: codon 201Gly type, codon 201Arg/Gly type, and codon 201Arg type. The codon 201Gly type occurred more frequently in disseminated (stages IV and IVs neuroblastomas (72% than in localized (stages I, II, and III tumors (48% (P=.035, and normal controls (38% (P=.024. In addition, the codon 201Gly type was significantly more common in tumors found clinically (65% than in those found by mass screening (35% (P=.002. The results suggested that the codon 201Gly type of the DCC gene might be associated with a higher risk of disseminating neuroblastoma.

  15. Polymorphism Sequence - JSNP | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available switchLanguage; BLAST Search Image Search Home About Archive Update History Data ...List Contact us JSNP Polymorphism Sequence Data detail Data name Polymorphism Sequence DOI 10.18908/lsdba.nb...dc00114-001 Description of data contents Information on polymorphisms (SNPs and insertions/deletions) and th...RL: ftp://ftp.biosciencedbc.jp/archive/jsnp/LATEST/jsnp_seq.zip File size: 10.6 MB Simple search URL http://...se Name database name JSNP_SNP: single nucleotide polymorphism JSNP_InsDel_IND: insertion/deletion JSNP_InsD

  16. Adding and Deleting Images

    Science.gov (United States)

    Images are added via the Drupal WebCMS Editor. Once an image is uploaded onto a page, it is available via the Library and your files. You can edit the metadata, delete the image permanently, and/or replace images on the Files tab.

  17. Molecular cytogenetic detection of chromosome 15 deletions in patients with Prader-Willi and Angelman syndromes

    Energy Technology Data Exchange (ETDEWEB)

    Chadwick, D.E.; Weksberg, R.; Shuman, C. [Hospital for Sick Children, Toronto (Canada)] [and others

    1994-09-01

    Prader-Willi syndrome (PWS) and Angelman syndrome (AS) are clinically distinct genetic disorders involving alterations of chromosome 15q11-q13. Approximately 75% of individuals with PWS and AS have deletions within 15q11-q13 by molecular analysis. We have evaluated fluorescence in situ hybridization (FISH) for the clinical laboratory detection of del(15)(q11q13) using the cosmid probes D15S11 and GABRB3 (ONCOR, Gaithersburg, NY). 4/4 PWS and 1/1 AS patients previously identified as having cytogenetic deletions were deleted for both probes. In a prospectively ascertained series of 54 patient samples referred to rule out either PWS or AS, 8 were deleted for D15S11 and GABRB3. In addition, an atypical deletion patient with PWS was also identified who was found to be deleted for GABRB3 but not D15S11. The SNRPN locus was also deleted in this patient. Only 4 of the 9 patient samples having molecular cytogenetic deletions were clearly deleted by high resolution banding (HRB) analysis. The microscopic and submicroscopic deletions have been confirmed by dinucleotide (CA) repeat analysis. Microsatellite polymorphism analysis was also used to demonstrate that five non-deletion patients in this series had biparental inheritance of chromosome 15, including region q11-q13. Deletions were not detected by either HRB, FISH or microsatellite polymorphism analysis in samples obtained from parents of the deletion patients. Methylation studies of chromosome 15q11-q13 are in progress for this series of PWS and AS families. FISH analysis of chromosome 15q11-q13 in patients with PWS and AS is a rapid, sensitive and reliable method for deletion detection.

  18. Parental origin of de novo chromosome 9 deletions in del(9p) syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Micale, M.A.; Haren, J.M.; Conroy, J.M. [Case Western University School of Medicine, Clevelend, OH (United States)

    1995-05-22

    Parental origin of de novo deletions in the short arm of chromosome 9 in patients with a clinical diagnosis of del(9p) syndrome was assessed in 13 patients using polymerase chain reaction (PCR) analysis of highly polymorphic dinucleotide repeat microsatellite markers located in the putative deleted region. The deletion was found to be of paternal origin in 9 cases and of maternal origin in the remaining 4 cases, suggesting that the molecular event resulting in the deletion occurs in both male and female gametogenesis and that genomic imprinting does not appear to play a role in the pathogenesis of del(9p) syndrome. 22 refs., 1 fig.

  19. Deletion of a target gene in Indica rice via CRISPR/Cas9.

    Science.gov (United States)

    Wang, Ying; Geng, Lizhao; Yuan, Menglong; Wei, Juan; Jin, Chen; Li, Min; Yu, Kun; Zhang, Ya; Jin, Huaibing; Wang, Eric; Chai, Zhijian; Fu, Xiangdong; Li, Xianggan

    2017-08-01

    Using CRISPR/Cas9, we successfully deleted large fragments of the yield-related gene DENSE AND ERECT PANICLE1 in Indica rice at relatively high frequency and generated gain-of-function dep1 mutants. CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 is a rapidly developing technology used to produce gene-specific modifications in both mammalian and plant systems. Most CRISPR-induced modifications in plants reported to date have been small insertions or deletions. Few large target gene deletions have thus far been reported, especially for Indica rice. In this study, we designed multiple CRISPR sgRNAs and successfully deleted DNA fragments in the gene DENSE AND ERECT PANICLE1 (DEP1) in the elite Indica rice line IR58025B. We achieved deletion frequencies of up to 21% for a 430 bp target and 9% for a 10 kb target among T0 events. Constructs with four sgRNAs did not generate higher full-length deletion frequencies than constructs with two sgRNAs. The multiple mutagenesis frequency reached 93% for four targets, and the homozygous mutation frequency reached 21% at the T0 stage. Important yield-related trait characteristics, such as dense and erect panicles and reduced plant height, were observed in dep1 homozygous T0 mutant plants produced by CRISPR/Cas9. Therefore, we successfully obtained deletions in DEP1 in the Indica background using the CRISPR/Cas9 editing tool at relatively high frequency.

  20. Model-based Estimation of High Frequency Jump Diffusions with Microstructure Noise and Stochastic Volatility

    NARCIS (Netherlands)

    Bos, Charles S.

    2008-01-01

    When analysing the volatility related to high frequency financial data, mostly non-parametric approaches based on realised or bipower variation are applied. This article instead starts from a continuous time diffusion model and derives a parametric analog at high frequency for it, allowing

  1. Outphasing control of gallium nitride based very high frequency resonant converters

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Knott, Arnold; Andersen, Michael A. E.

    2015-01-01

    In this paper an outphasing modulation control method suitable for line regulation of very high frequency resonant converters is described. The pros and cons of several control methods suitable for very high frequency resonant converters are described and compared to outphasing modulation...

  2. High frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis in Brazilian patients with neurofibromatosis type 1

    Directory of Open Access Journals (Sweden)

    Trovó-Marqui A.B.

    2005-01-01

    Full Text Available A clinical study of Brazilian patients with neurofibromatosis type 1 (NF1 was performed in a multidisciplinary Neurofibromatosis Program called CEPAN (Center of Research and Service in Neurofibromatosis. Among 55 patients (60% females, 40% males who met the NIH criteria for the diagnosis of NF1, 98% had more than six café-au-lait patches, 94.5% had axillary freckling, 45% had inguinal freckling, and 87.5% had Lisch nodules. Cutaneous neurofibromas were observed in 96%, and 40% presented plexiform neurofibromas. A positive family history of NF1 was found in 60%, and mental retardation occurred in 35%. Some degree of scoliosis was noted in 49%, 51% had macrocephaly, 40% had short stature, 76% had learning difficulties, and 2% had optic gliomas. Unexpectedly high frequencies of plexiform neurofibromas, mental retardation, learning difficulties, and scoliosis were observed, probably reflecting the detailed clinical analysis methods adopted by the Neurofibromatosis Program. These same patients were screened for mutations in the GAP-related domain/GRD (exons 20-27a by single-strand conformation polymorphism. Four different mutations (Q1189X, 3525-3526delAA, E1356G, c.4111-1G>A and four polymorphisms (c.3315-27G>A, V1146I, V1317A, c.4514+11C>G were identified. These data were recently published.

  3. (AJST) GENERALISED DELETION DESIGNS

    African Journals Online (AJOL)

    Following Dean (1978), for a given contrast vector x c , the loss of information x ψ ,. 1. 0. ≤. ≤ x ψ. , due to confounding with blocks, is given by x x x. 1 x x cc. cN. KNc ψ. 1. ′. = −. ′. (3.3). Where N is the incidence matrix and K is the diagonal matrix of block sizes. We consider deletion designs of the form. ( ) 1. 1 m m n ls s.

  4. A comparative survey of the frequency and distribution of polymorphism in the genome of Xenopus tropicalis.

    Directory of Open Access Journals (Sweden)

    Chris Showell

    Full Text Available Naturally occurring DNA sequence variation within a species underlies evolutionary adaptation and can give rise to phenotypic changes that provide novel insight into biological questions. This variation exists in laboratory populations just as in wild populations and, in addition to being a source of useful alleles for genetic studies, can impact efforts to identify induced mutations in sequence-based genetic screens. The Western clawed frog Xenopus tropicalis (X. tropicalis has been adopted as a model system for studying the genetic control of embryonic development and a variety of other areas of research. Its diploid genome has been extensively sequenced and efforts are underway to isolate mutants by phenotype- and genotype-based approaches. Here, we describe a study of genetic polymorphism in laboratory strains of X. tropicalis. Polymorphism was detected in the coding and non-coding regions of developmental genes distributed widely across the genome. Laboratory strains exhibit unexpectedly high frequencies of genetic polymorphism, with alleles carrying a variety of synonymous and non-synonymous codon substitutions and nucleotide insertions/deletions. Inter-strain comparisons of polymorphism uncover a high proportion of shared alleles between Nigerian and Ivory Coast strains, in spite of their distinct geographical origins. These observations will likely influence the design of future sequence-based mutation screens, particularly those using DNA mismatch-based detection methods which can be disrupted by the presence of naturally occurring sequence variants. The existence of a significant reservoir of alleles also suggests that existing laboratory stocks may be a useful source of novel alleles for mapping and functional studies.

  5. Combinational light emitting diode-high frequency focused ultrasound treatment for HeLa cell.

    Science.gov (United States)

    Choe, Se-Woon; Park, Kitae; Park, Chulwoo; Ryu, Jaemyung; Choi, Hojong

    2017-12-01

    Light sources such as laser and light emitting diode or ultrasound devices have been widely used for cancer therapy and regenerative medicines, since they are more cost-effective and less harmful than radiation therapy, chemotherapy or magnetic treatment. Compared to laser and low intensity ultrasound techniques, light emitting diode and high frequency focused ultrasound shows enhanced therapeutic effects, especially for small tumors. We propose combinational light emitting diode-high frequency focused ultrasound treatment for human cervical cancer HeLa cells. Individual red, green, and blue light emitting diode light only, high frequency focused ultrasound only, or light emitting diode light combined with high frequency focused ultrasound treatments were applied in order to characterize the responses of HeLa cells. Cell density exposed by blue light emitting diode light combined with high frequency focused ultrasound (2.19 ± 0.58%) was much lower than that of cells exposed by red and green light emitting diode lights (81.71 ± 9.92% and 61.81 ± 4.09%), blue light emitting diode light (11.19 ± 2.51%) or high frequency focused ultrasound only (9.72 ± 1.04%). We believe that the proposed combinational blue light emitting diode-high frequency focused ultrasound treatment could have therapeutic benefits to alleviate cancer cell proliferation.

  6. Test the mergers of the primordial black holes by high frequency gravitational-wave detector

    Science.gov (United States)

    Li, Xin; Wang, Li-Li; Li, Jin

    2017-09-01

    The black hole could have a primordial origin if its mass is less than 1M_⊙. The mergers of these black hole binaries generate stochastic gravitational-wave background (SGWB). We investigate the SGWB in high frequency band 108-10^{10} Hz. It can be detected by high frequency gravitational-wave detector. Energy density spectrum and amplitude of the SGWB are derived. The upper limit of the energy density spectrum is around 10^{-7}. Also, the upper limit of the amplitude ranges from 10^{-31.5} to 10^{-29.5}. The fluctuation of spacetime origin from gravitational wave could give a fluctuation of the background electromagnetic field in a high frequency gravitational-wave detector. The signal photon flux generated by the SGWB in the high frequency band 108-10^{10} Hz is derived, which ranges from 1 to 10^2 s^{-1}. The comparison between the signal photon flux generated by relic gravitational waves (RGWs) and the SGWB is also discussed in this paper. It is shown that the signal photon flux generated by the RGW, which is predicted by the canonical single-field slow-roll inflation models, is sufficiently lower than the one generated by the SGWB in the high frequency band 108-10^{10} Hz. Our results indicate that the SGWB in the high frequency band 108-10^{10} Hz is more likely to be detected by the high frequency gravitational-wave detector.

  7. High frequency of germline p53 mutations in childhood adrenocortical cancer.

    Science.gov (United States)

    Wagner, J; Portwine, C; Rabin, K; Leclerc, J M; Narod, S A; Malkin, D

    1994-11-16

    Adrenocortical carcinoma (ADCC) is a rare childhood cancer, affecting three of 1 million children younger than 16 years old in the United States. ADCC may be found in association with the Li-Fraumeni and Beckwith-Wiedemann syndromes. Children with ADCC are also at substantially increased risk of second primary cancers. Because of these associations, it is believed that the genetic basis for ADCC is stronger than for most childhood malignancies. Germline mutations of the TP53 tumor suppressor gene are associated with cancer predisposition in families with the Li-Fraumeni syndrome as well as in individuals with sporadically occurring component tumors of the syndrome. We investigated the possibility that germline TP53 gene alterations existed in children with ADCC. Sixteen children with ADCC under the age of 18 were identified from searches of medial oncology records at three Canadian hospitals. Eleven of these 16 patients identified were alive. The mean age at diagnosis was 4.8 years (range, 1-17 years). Family histories were obtained for 11 unselected children with ADCC (six girls and five boys). Pathologic confirmation of tumor diagnosis was obtained from the medical records. Using single-strand conformational polymorphism analysis followed by single-strand DNA sequencing, genomic DNA extracted from whole blood was analyzed for the presence of TP53 mutations for six living ADCC patients. Three of six (50%) children were found to carry germline TP53 mutations in exons 5, 6, and 7, respectively. Both wild-type and mutant alleles were identified in all three TP53 sequences, indicating that the patients were heterozygous for germline TP53 mutations. None of these children was from a family with the Li-Fraumeni syndrome. The mutation in one child was shown to be inherited from the mother, who subsequently developed breast cancer. A striking excess of cancer was found in one family of a patient carrying wild-type TP53. Our observation of a high frequency of germline TP53

  8. Analysis of three polymorphisms in Bidayuh ethnic of Sarawak ...

    African Journals Online (AJOL)

    Insertion/deletion polymorphism of YAP (DYS287), M96 and M120 polymorphisms in Bidayuh ethnic populations of Sarawak, Malaysia were analyzed in this study. Genomic DNA was extracted from 180 buccal samples and amplified by Hot-Start PCR method. The amplified PCR products were separated by using 2% ...

  9. HLA-G polymorphisms in couples with recurrent spontaneous abortions

    DEFF Research Database (Denmark)

    Hviid, T V; Hylenius, S; Hoegh, A M

    2002-01-01

    % of the RSA women carried the HLA-G*0106 allele compared to 2% of the control women. The 14 bp deletion polymorphism in exon 8 was investigated separately. There were a greater number of heterozygotes for the 14 bp polymorphism in the group of fertile control women than expected, according to Hardy-Weinberg...

  10. Genotyping of FCN and MBL2 Polymorphisms Using Pyrosequencing

    DEFF Research Database (Denmark)

    Munthe-Fog, Lea; Madsen, Hans Ole; Garred, Peter

    2014-01-01

    Pyrosequencing represents one of the most thorough methods used to analyze polymorphisms. One advantage of using pyrosequencing for genotyping is the ability to identify not only single-nucleotide polymorphisms (SNPs) but also tri-allelic variations, insertions and deletions (InDels). In contrast...

  11. The entire β-globin gene cluster is deleted in a form of τδβ-thalassemia.

    NARCIS (Netherlands)

    E.R. Fearon; H.H.Jr. Kazazian; P.G. Waber (Pamela); J.I. Lee (Joseph); S.E. Antonarakis; S.H. Orkin (Stuart); E.F. Vanin; P.S. Henthorn; F.G. Grosveld (Frank); A.F. Scott; G.R. Buchanan

    1983-01-01

    textabstractWe have used restriction endonuclease mapping to study a deletion involving the beta-globin gene cluster in a Mexican-American family with gamma delta beta-thalassemia. Analysis of DNA polymorphisms demonstrated deletion of the beta-globin gene from the affected chromosome. Using a DNA

  12. Excitation of plasma waves by nonlinear currents induced by a high-frequency electromagnetic pulse

    Energy Technology Data Exchange (ETDEWEB)

    Grishkov, V. E.; Uryupin, S. A., E-mail: uryupin@sci.lebedev.ru [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2017-03-15

    Excitation of plasma waves by nonlinear currents induced by a high-frequency electromagnetic pulse is analyzed within the kinetic approach. It is shown that the most efficient source of plasma waves is the nonlinear current arising due to the gradient of the energy density of the high-frequency field. Generation of plasma waves by the drag current is usually less efficient but not negligibly small at relatively high frequencies of electron–ion collisions. The influence of electron collisions on the excitation of plasma waves by pulses of different duration is described quantitatively.

  13. Killer whale (Orcinus orca) whistles from the western South Atlantic Ocean include high frequency signals.

    Science.gov (United States)

    Andriolo, Artur; Reis, Sarah S; Amorim, Thiago O S; Sucunza, Federico; de Castro, Franciele R; Maia, Ygor Geyer; Zerbini, Alexandre N; Bortolotto, Guilherme A; Dalla Rosa, Luciano

    2015-09-01

    Acoustic parameters of killer whale (Orcinus orca) whistles were described for the western South Atlantic Ocean and highlight the occurrence of high frequency whistles. Killer whale signals were recorded on December of 2012, when a pod of four individuals was observed harassing a group of sperm whales. The high frequency whistles were highly stereotyped and were modulated mostly at ultrasonic frequencies. Compared to other contour types, the high frequency whistles are characterized by higher bandwidths, shorter durations, fewer harmonics, and higher sweep rates. The results add to the knowledge of vocal behavior of this species.

  14. Econometric analysis of realized covariation: high frequency based covariance, regression, and correlation in financial economics

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole Eiler; Shephard, N.

    2004-01-01

    This paper analyses multivariate high frequency financial data using realized covariation. We provide a new asymptotic distribution theory for standard methods such as regression, correlation analysis, and covariance. It will be based on a fixed interval of time (e.g., a day or week), allowing...... the number of high frequency returns during this period to go to infinity. Our analysis allows us to study how high frequency correlations, regressions, and covariances change through time. In particular we provide confidence intervals for each of these quantities....

  15. High-frequency side-scan sonar fish reconnaissance by autonomous underwater vehicles

    National Research Council Canada - National Science Library

    Lynch, James F; Vogel, Kaela S; Grothues, Thomas M; Newhall, Arthur E; Gawarkiewicz, Glen G

    .... Moving high-frequency sources to depth using autonomous underwater vehicles (AUVs) mitigates this and also co-locates transducers with other AUV-mounted short-range sensors to allow a holistic approach to ecological surveys...

  16. Deriving animal behaviour from high-frequency GPS: tracking cows in open and forested habitat

    NARCIS (Netherlands)

    de Weerd, N.; van Langevelde, F.; van Oeveren, H.; Nolet, Bart A.; Kölzsch, Andrea; Prins, H.H.T.; De Boer, W.F.

    2015-01-01

    The increasing spatiotemporal accuracy of Global Navigation Satellite Systems (GNSS) tracking systems opens the possibility to infer animal behaviour from tracking data. We studied the relationship between high-frequency GNSS data and behaviour, aimed at developing an easily interpretable

  17. Effect of magnetic bending on the EBT high-frequency modes

    Energy Technology Data Exchange (ETDEWEB)

    El-Nadi, A.M.; Hiroe, S.; Whitson, J.C.; Hassen, H.F.; Kirolous, H.A.

    1986-02-01

    The high-frequency stability of the ELMO Bumpy Torus (EBT) device is studied when the wave vector has a finite component along the magnetic field lines. Unstable modes exist for any finite hot electron density. 9 refs., 1 fig.

  18. High-Frequency Binaural Beats Increase Cognitive Flexibility: Evidence from Dual-Task Crosstalk

    National Research Council Canada - National Science Library

    Hommel, Bernhard; Sellaro, Roberta; Fischer, Rico; Borg, Saskia; Colzato, Lorenza S

    2016-01-01

    ...) or flexibility (by dampening competition and biasing). We investigated whether high-frequency binaural beats, an auditory illusion suspected to act as a cognitive enhancer, have an impact on cognitive-control configuration...

  19. High-Frequency Electrocardiography: Optimizing the Diagnosis of the Acute Myocardial Infarct with ST-Elevation

    Science.gov (United States)

    Naydenov, S.; Donova, T.; Matveev, M.; Gegova, A.; Popdimitrova, N.; Zlateva, G.; Vladimirova, D.

    2007-04-01

    The analysis of the received digital signal by computer microprocessor in high-frequency electrocardiography, used in our research, makes possible synthesis of vectorcardiographic images and loops, allowing improved qualitative and quantitative diagnosing of the myocardial injury.

  20. High frequency study of nutrient fluxes variability in a small river

    Science.gov (United States)

    Zongo, S. B.; Schmitt, F. G.

    2012-04-01

    We consider here high frequency nutrient fluxes recorded during two one month duration campaigns in 2010 and 2011 in the Wimereux river (North of France). During these campaigns, the river flow is recorded every 10 minutes, simultaneously with NO3, NH4, PO4 and COT data. High frequency fluxes are computed. We first compare these high frequency estimations with low frequency (1 measurement every month) estimations in order to quantify the error in the latter. We also consider the pdf of the ratio of high frequency fluxes ("true" values) to low frequency estimation. We finally consider the scaling properties of the fluctuations of the nutrient data, flow data, and of the fluxes. This study was supported by a grant from Agence de l'Eau Artois Picardie.

  1. An algorithm for on-line detection of high frequency oscillations related to epilepsy.

    Science.gov (United States)

    López-Cuevas, Armando; Castillo-Toledo, Bernardino; Medina-Ceja, Laura; Ventura-Mejía, Consuelo; Pardo-Peña, Kenia

    2013-06-01

    Recent studies suggest that the appearance of signals with high frequency oscillations components in specific regions of the brain is related to the incidence of epilepsy. These oscillations are in general small in amplitude and short in duration, making them difficult to identify. The analysis of these oscillations are particularly important in epilepsy and their study could lead to the development of better medical treatments. Therefore, the development of algorithms for detection of these high frequency oscillations is of great importance. In this work, a new algorithm for automatic detection of high frequency oscillations is presented. This algorithm uses approximate entropy and artificial neural networks to extract features in order to detect and classify high frequency components in electrophysiological signals. In contrast to the existing algorithms, the one proposed here is fast and accurate, and can be implemented on-line, thus reducing the time employed to analyze the experimental electrophysiological signals. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  2. Efficient Estimation for Diffusions Sampled at High Frequency Over a Fixed Time Interval

    DEFF Research Database (Denmark)

    Jakobsen, Nina Munkholt; Sørensen, Michael

    Parametric estimation for diffusion processes is considered for high frequency observations over a fixed time interval. The processes solve stochastic differential equations with an unknown parameter in the diffusion coefficient. We find easily verified conditions on approximate martingale...

  3. Low and High-Frequency Field Potentials of Cortical Networks Exhibit Distinct Responses to Chemicals

    Science.gov (United States)

    Neural networks grown on microelectrode arrays (MEAs) have become an important, high content in vitro assay for assessing neuronal function. MEA experiments typically examine high- frequency (HF) (>200 Hz) spikes, and bursts which can be used to discriminate between differ...

  4. High Frequency Radar Locations in the United States as of February 2016.

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This dataset show the point locations of High Frequency (HF) radar systems across the US. HF radars measure the speed and direction of ocean surface currents in near...

  5. High frequency of CYP2D6 ultrarapid metabolizer genotypes in an Ashkenazi Jewish population from Argentina.

    Science.gov (United States)

    Moya, G; Dorado, P; Ferreiro, V; Naranjo, M E G; Peñas-Lledó, E M; LLerena, A

    2017-07-01

    A twofold higher frequency of CYP2D6 ultrarapid metabolizers (estimated from genotype: gUMs) was reported among Ashkenazi Jews (AJ) living in New York (USA) than in other North American Caucasians, which might be important to guide the prescription for CYP2D6 substrates in AJ communities around the world. This study was aimed to determine whether the high frequency of CYP2D6 gUMs described in AJ from USA was replicated in AJ from Argentina when compared with other multiethnic admixture Argentines (GA). The frequency of the most common allelic variants and of CYP2D6 gUMs (>2 active genes) and poor metabolizers (0 active genes, gPMs) was also compared among the studied Argentine populations. CYP2D6 genotyping was performed in 173 AJ and 246 GA DNA samples of unrelated donors from the metropolitan area of Buenos Aires. CYP2D6 alleles (*2, *3, *4, *5, *6, *10, *17, *35, *41 and multiple copies), genotypes and functional phenotype frequencies were determined. The frequencies of gUMs and gPMs in AJ from Argentina were 11.5% and 5.2%, respectively, whereas in GA, the frequencies of gUM and gPMs were 6.5% and 4.9%, respectively. Comparisons between AJ and GA showed that gUMs frequencies were twofold higher (PAJ than GA. CYP2D6*35 allele was more frequent in GA than AJ, whereas CYP2D6*41 and *1xN were more frequent in AJ than in GA (P<0.05). This study supports the previously reported high frequency of gUMs on another Ashkenazi population in New York. The present findings also support the interethnic variability of CYP2D6 genetic polymorphism in the overall Argentine population.

  6. Family Polymorphism

    DEFF Research Database (Denmark)

    Ernst, Erik

    2001-01-01

    safety and flexibility at the level of multi-object systems. We are granted the flexibility of using different families of kinds of objects, and we are guaranteed the safety of the combination. This paper highlights the inability of traditional polymorphism to handle multiple objects, and presents family...... polymorphism as a way to overcome this problem. Family polymorphism has been implemented in the programming language gbeta, a generalized version of Beta, and the source code of this implementation is available under GPL....

  7. The Impact of Very High Frequency Surface Reverberation on Coherent Acoustic Propagation and Modeling

    Science.gov (United States)

    2015-09-30

    The third primary objective is to characterize high frequency wave noise in environmental simulators , the surf zone and the open ocean. 2 In...conducted in a wind-wave simulator at Scripps Institution of Oceanography, and will transition next year to the littoral zone off La Jolla Shores Beach...and work in this initial phase has focused on laboratory measurements of high frequency surface scattering, simulations of the scattered signal and

  8. Influence of high frequency electric field on the dispersion of ion-acoustic waves in plasma

    Energy Technology Data Exchange (ETDEWEB)

    Turky, A.; Cercek, M.; Tavzes, R.

    1981-01-01

    The modification of the ion-acoustic wave dispersion under the action of a high frequency electric field was studied experimentally, the wave propagating along and against the plasma stream. The frequency of the field amounted to approximately half the electron plasma frequency. It was found that the phase velocity of the ion wave and the plasma drift velocity decrease as the effective high frequency field power increases.

  9. Conventional Audiometry, Extended High-Frequency Audiometry, and DPOAE for Early Diagnosis of NIHL

    OpenAIRE

    Mehrparvar, Amir Houshang; Mirmohammadi, Seyyed Jalil; Davari, Mohammad Hossein; Mostaghaci, Mehrdad; Mollasadeghi, Abolfazl; Bahaloo, Maryam; Hashemi, Seyyed Hesam

    2014-01-01

    Background: Noise most frequently affects hearing system, as it may typically cause a bilateral, progressive sensorineural hearing loss at high frequencies. Objectives: This study was designed to compare three different methods to evaluate noise-induced hearing loss (conventional audiometry, high-frequency audiometry, and distortion product otoacoustic emission). Material and Methods: This was a cross-sectional study. Data was analyzed by SPSS (ver. 19) using chi square, T test and repeated m...

  10. Optimization of the High-Frequency Radar Sites in the Bering Strait Region

    Science.gov (United States)

    2015-02-01

    Optimization of the High-Frequency Radar Sites in the Bering Strait Region GLEB PANTELEEV International Arctic Research Center, University of Alaska...climatological data in the Bering Strait (BS) region are synthesized with dynamical constraints of a numerical model. The optimal HFR placement...00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Optimization of the High-Frequency Radar Sites in the Bering Strait Region 5a. CONTRACT NUMBER 5b

  11. High-Frequency Percussive Ventilation: Pneumotachograph Validation and Tidal Volume Analysis

    Science.gov (United States)

    2010-06-01

    percussive ventilation (HFPV) is an increasingly used mode of mechanical ventilation , for which there is no proven real-time means of measuring delivered... mechanical ventilation ; tidal volume; VT; pneumotachography. [Respir Care 2010;55(6):734–740] Introduction Clinical application of high-frequency percussive...conventional mechanical ventilation (Fig. 1). How- ever, neither the low-frequency nor the high-frequency volumes administered by HFPV are measured by the

  12. Price duration versus trading volume in high-frequency data for selected DAX companies

    OpenAIRE

    Christoph Mitterer; Henryk Gurgul; Robert Syrek

    2016-01-01

    The properties of the time series of durations between consecutive trades of a particular stock have been studied by many contributors in the literature of financial econometrics. Among them are highly prominent scientists like Engle (2000) and Gourieroux and Jasiak (2001). The importance of this topic, accompanied by the growing availability of (ultra-)high-frequency data, has prompted an increase of contributions in recent years. Intensive research based on high-frequency data has several ...

  13. Advanced High-Frequency Electronic Ballasting Techniques for Gas Discharge Lamps

    OpenAIRE

    Tao, Fengfeng

    2001-01-01

    Small size, light weight, high efficacy, longer lifetime and controllable output are the main advantages of high-frequency electronic ballasts for gas discharge lamps. However, power line quality and electromagnetic interference (EMI) issues arise when a simple peak rectifying circuit is used. To suppress harmonic currents and improve power factor, input-current-shaping (ICS) or power-factor-correction (PFC) techniques are necessary. This dissertation addresses advanced high-frequency elec...

  14. Implementation of Low Frequency Ac to High Frequency Ac with Single Stage Zvs-Pwm Inverter

    OpenAIRE

    S. Arumugam S. Ramareddy M. Sridhar

    2011-01-01

    This paper presents a novel soft-switching pulse width modulation (PWM) utility frequency AC to high frequency (HF) AC power conversion circuit incorporating boost-active clamp single stage inverter topology. This power converter is more suitable and acceptable for cost effective HF consumer induction heating applications. Its operating principle is presented. The operating performances of this high frequency inverter using the latest insulated gate bipolar transistors are illustrated, which ...

  15. Design of Plasma Generator Driven by High-frequency High-voltage Power Supply

    OpenAIRE

    Yong-Nong, C.; K. Chih-Ming

    2013-01-01

    In this research, a high-frequency high-voltage power supply designed for plasma generator is presented. The power supply mainly consists of a series resonant converter with a high-frequency high-voltage boost transformer. Due to the indispensable high-voltage inheritance in the operation of plasma generator, the analysis of transformer need considering not only winding resistance, leakage inductance, magnetizing inductance, and core-loss resistance, but also parasitic capacitance resulted fr...

  16. Metronidazole as a protector of cells from electromagnetic radiation of extremely high frequencies

    Science.gov (United States)

    Kuznetsov, Pavel E.; Malinina, Ulia A.; Popyhova, Era B.; Rogacheva, Svetlana M.; Somov, Alexander U.

    2006-08-01

    It is well known that weak electromagnetic fields of extremely high frequencies cause significant modification of the functional status of biological objects of different levels of organization. The aim of the work was to study the combinatory effect of metronidazole - the drug form of 1-(2'hydroxiethil)-2-methil-5-nitroimidazole - and electromagnetic radiation of extremely high frequencies (52...75 GHz) on the hemolytic stability of erythrocytes and hemotaxis activity of Infusoria Paramecium caudatum.

  17. Whole-Genome SNP Association in the Horse: Identification of a Deletion in Myosin Va Responsible for Lavender Foal Syndrome

    Science.gov (United States)

    Brooks, Samantha A.; Gabreski, Nicole; Miller, Donald; Brisbin, Abra; Brown, Helen E.; Streeter, Cassandra; Mezey, Jason; Cook, Deborah; Antczak, Douglas F.

    2010-01-01

    Lavender Foal Syndrome (LFS) is a lethal inherited disease of horses with a suspected autosomal recessive mode of inheritance. LFS has been primarily diagnosed in a subgroup of the Arabian breed, the Egyptian Arabian horse. The condition is characterized by multiple neurological abnormalities and a dilute coat color. Candidate genes based on comparative phenotypes in mice and humans include the ras-associated protein RAB27a (RAB27A) and myosin Va (MYO5A). Here we report mapping of the locus responsible for LFS using a small set of 36 horses segregating for LFS. These horses were genotyped using a newly available single nucleotide polymorphism (SNP) chip containing 56,402 discriminatory elements. The whole genome scan identified an associated region containing these two functional candidate genes. Exon sequencing of the MYO5A gene from an affected foal revealed a single base deletion in exon 30 that changes the reading frame and introduces a premature stop codon. A PCR–based Restriction Fragment Length Polymorphism (PCR–RFLP) assay was designed and used to investigate the frequency of the mutant gene. All affected horses tested were homozygous for this mutation. Heterozygous carriers were detected in high frequency in families segregating for this trait, and the frequency of carriers in unrelated Egyptian Arabians was 10.3%. The mapping and discovery of the LFS mutation represents the first successful use of whole-genome SNP scanning in the horse for any trait. The RFLP assay can be used to assist breeders in avoiding carrier-to-carrier matings and thus in preventing the birth of affected foals. PMID:20419149

  18. Whole-genome SNP association in the horse: identification of a deletion in myosin Va responsible for Lavender Foal Syndrome.

    Directory of Open Access Journals (Sweden)

    Samantha A Brooks

    2010-04-01

    Full Text Available Lavender Foal Syndrome (LFS is a lethal inherited disease of horses with a suspected autosomal recessive mode of inheritance. LFS has been primarily diagnosed in a subgroup of the Arabian breed, the Egyptian Arabian horse. The condition is characterized by multiple neurological abnormalities and a dilute coat color. Candidate genes based on comparative phenotypes in mice and humans include the ras-associated protein RAB27a (RAB27A and myosin Va (MYO5A. Here we report mapping of the locus responsible for LFS using a small set of 36 horses segregating for LFS. These horses were genotyped using a newly available single nucleotide polymorphism (SNP chip containing 56,402 discriminatory elements. The whole genome scan identified an associated region containing these two functional candidate genes. Exon sequencing of the MYO5A gene from an affected foal revealed a single base deletion in exon 30 that changes the reading frame and introduces a premature stop codon. A PCR-based Restriction Fragment Length Polymorphism (PCR-RFLP assay was designed and used to investigate the frequency of the mutant gene. All affected horses tested were homozygous for this mutation. Heterozygous carriers were detected in high frequency in families segregating for this trait, and the frequency of carriers in unrelated Egyptian Arabians was 10.3%. The mapping and discovery of the LFS mutation represents the first successful use of whole-genome SNP scanning in the horse for any trait. The RFLP assay can be used to assist breeders in avoiding carrier-to-carrier matings and thus in preventing the birth of affected foals.

  19. Test the mergers of the primordial black holes by high frequency gravitational-wave detector

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xin; Wang, Li-Li; Li, Jin [Chongqing University, Department of Physics, Chongqing (China)

    2017-09-15

    The black hole could have a primordial origin if its mass is less than 1M {sub CircleDot}. The mergers of these black hole binaries generate stochastic gravitational-wave background (SGWB). We investigate the SGWB in high frequency band 10{sup 8}-10{sup 10} Hz. It can be detected by high frequency gravitational-wave detector. Energy density spectrum and amplitude of the SGWB are derived. The upper limit of the energy density spectrum is around 10{sup -7}. Also, the upper limit of the amplitude ranges from 10{sup -31.5} to 10{sup -29.5}. The fluctuation of spacetime origin from gravitational wave could give a fluctuation of the background electromagnetic field in a high frequency gravitational-wave detector. The signal photon flux generated by the SGWB in the high frequency band 10{sup 8}-10{sup 10} Hz is derived, which ranges from 1 to 10{sup 2} s{sup -1}. The comparison between the signal photon flux generated by relic gravitational waves (RGWs) and the SGWB is also discussed in this paper. It is shown that the signal photon flux generated by the RGW, which is predicted by the canonical single-field slow-roll inflation models, is sufficiently lower than the one generated by the SGWB in the high frequency band 10{sup 8}-10{sup 10} Hz. Our results indicate that the SGWB in the high frequency band 10{sup 8}-10{sup 10} Hz is more likely to be detected by the high frequency gravitational-wave detector. (orig.)

  20. SMN1 and NAIP Genes Deletions in Different Types of Spinal Muscular Atrophy in Khuzestan Province, Iran

    Directory of Open Access Journals (Sweden)

    Gholamreza Mohamadian

    2011-12-01

    Full Text Available Background: Spinal muscular atrophy (SMA is the second most common lethal autosomal recessive disease. It is a neuromuscular disorder caused by degenerative of lower motor neurons and occasionally bulbar neurons leading to progressive limb paralysis and muscular atrophy. The SMN1 gene is recognized as a SMA causing gene while NAIP has been characterized as a modifying factor for the clinical severity and age at disease onset in SMA patients (SMA subtypes. The relationship between NAIP deletion and type of SMA remains to be clarified; we investigated this gene alteration in all types of SMA patients. Methods: Molecular analysis was performed on fifty patients with a clinical diagnosis of SMA in Khuzestan province. In addition to common PCR-RFLP analysis for exon 7 and 8 of SMN1 gene, as an internal control we analysed NAIP deletion with PCR of exon 5 of this gene in a multiplex PCR with exon 13 of it. Results: Homozygous-deletion frequency rate for the telomeric copy of SMN (SMN1 exon 7 in all types (type I, II, Ш of SMA was approximately 90% and the frequency of deletion in exon 7 and 8 together in all types estimated about 70%. Moreover NAIP gene was deleted in about 60% of these patients and this shows deletion in 91% of type I SMA patients. The correlation between NAIP-deletion and SMN1 mutation showed a high frequency rate. Conclusion: In this study, high frequency of NAIP gene deletion in all type of disease shows the importance role of it in disease pathogenesis. High frequency of NAIP deletion in SMA type I, also shows the importance of the gene in type and severity of disease so it may be a modifier factor in severity of disease.

  1. Ancient DNA analysis reveals high frequency of European lactase persistence allele (T-13910 in medieval central europe.

    Directory of Open Access Journals (Sweden)

    Annina Krüttli

    Full Text Available Ruminant milk and dairy products are important food resources in many European, African, and Middle Eastern societies. These regions are also associated with derived genetic variants for lactase persistence. In mammals, lactase, the enzyme that hydrolyzes the milk sugar lactose, is normally down-regulated after weaning, but at least five human populations around the world have independently evolved mutations regulating the expression of the lactase-phlorizin-hydrolase gene. These mutations result in a dominant lactase persistence phenotype and continued lactase tolerance in adulthood. A single nucleotide polymorphism (SNP at C/T-13910 is responsible for most lactase persistence in European populations, but when and where the T-13910 polymorphism originated and the evolutionary processes by which it rose to high frequency in Europe have been the subject of strong debate. A history of dairying is presumed to be a prerequisite, but archaeological evidence is lacking. In this study, DNA was extracted from the dentine of 36 individuals excavated at a medieval cemetery in Dalheim, Germany. Eighteen individuals were successfully genotyped for the C/T-13910 SNP by molecular cloning and sequencing, of which 13 (72% exhibited a European lactase persistence genotype: 44% CT, 28% TT. Previous ancient DNA-based studies found that lactase persistence genotypes fall below detection levels in most regions of Neolithic Europe. Our research shows that by AD 1200, lactase persistence frequency had risen to over 70% in this community in western Central Europe. Given that lactase persistence genotype frequency in present-day Germany and Austria is estimated at 71-80%, our results suggest that genetic lactase persistence likely reached modern levels before the historic population declines associated with the Black Death, thus excluding plague-associated evolutionary forces in the rise of lactase persistence in this region. This new evidence sheds light on the dynamic

  2. Effect of near-surface topography on high-frequency Rayleigh-wave propagation

    Science.gov (United States)

    Wang, Limin; Xu, Yixian; Xia, Jianghai; Luo, Yinhe

    2015-05-01

    Rayleigh waves, which are formed due to interference of P- and Sv-waves near the free surface, propagate along the free surface and vanish exponentially in the vertical direction. Their propagation is strongly influenced by surface topography. Due to the high resolution and precision requirements of near-surface investigations, the high-frequency Rayleigh waves are usually used for near-surface structural detecting. Although there are some numerical studies on high-frequency Rayleigh-wave propagation on topographic free surface, detailed analysis of characters of high-frequency Rayleigh-wave propagation on topographic free surface remains untouched. Hence, research of propagation of Rayleigh waves on complex topographic surface becomes critical for Rayleigh-wave methods in near-surface applications. To study the propagation of high-frequency Rayleigh waves on topographic free surface, two main topographic models are designed in this study. One of the models contains a depressed topographic surface, and another contains an uplifted topographic surface. We numerically simulate the propagation of high-frequency Rayleigh waves on these two topographic surfaces by finite-difference method. Soon afterwards, we analyze the propagation character of high-frequency Rayleigh waves on such topographic models, and compare the variations on its energy and frequency before and after passing the topographic region. At last, we discuss the relationship between the variations and topographical steepness of each model. Our numerical results indicate that influence of depressed topography for high-frequency Rayleigh waves is more distinct than influence of uplifted topography. Rayleigh waves produce new scattering body waves during passing the depressed topography with reduction of amplitude and loss of high-frequency components. Moreover, the steeper the depressed topography is, the more energy of Rayleigh waves is lost. The uplifted topography with gentle slope produces similar

  3. High-frequency profile in adolescents and its relationship with the use of personal stereo devices.

    Science.gov (United States)

    Silvestre, Renata Almeida Araújo; Ribas, Ângela; Hammerschmidt, Rogério; de Lacerda, Adriana Bender Moreira

    2016-01-01

    To analyze and correlate the audiometric findings of high frequencies (9-16 kHz) in adolescents with their hearing habits and attitudes, in order to prevent noise-induced hearing loss. This was a descriptive cross-sectional study, which included 125 adolescents in a sample of normal-hearing students, at a state school. The subjects performed high-frequency audiometry testing and answered a self-administered questionnaire addressing information on sound habits concerning the use of personal stereo devices. The sample was divided according to the exposure characteristics (time, duration, intensity, etc.) and the results were compared with the observed thresholds, through the difference in proportions test, chi-squared, Student's t-test, and ANOVA, all at a significance level of 0.05. Average high-frequency thresholds were registered below 15 dB HL and no significant correlation was found between high frequency audiometric findings and the degree of exposure. The prevalence of harmful sound habits due to the use of personal stereo devices is high in the adolescent population, but there was no correlation between exposure to high sound pressure levels through personal stereos and the high-frequency thresholds in this population. Copyright © 2016 Sociedade Brasileira de Pediatria. Published by Elsevier Editora Ltda. All rights reserved.

  4. High-frequency audiometry in normal hearing military firemen exposed to noise.

    Science.gov (United States)

    Rocha, Rita Leniza Oliveira da; Atherino, Ciríaco Cristóvão Tavares; Frota, Silvana Maria Monte Coelho

    2010-01-01

    The study of high frequencies has proven its importance for detecting inner ear damage. In some cases, conventional frequencies are not sensitive enough to pick up early changes to the inner ear. To analyze the results of threshold high frequency analysis of individuals exposed to noise with normal conventional audiometry. This was a retrospective cross-sectional cohort study, in which we studied 47 firefighters of the Fire Department of Rio de Janeiro, based on Santos Dumont airport and 33 military men without noise exposure. They were broken down into two age groups: 30-39years and 40-49years. The high frequencies were studied immediately after conventional audiometry. The results were most significant in the 40 to 49 years of age range, where the experimental group showed significantly higher threshold values than the control group 14000Hz (p = 0.008) and 16,000Hz (p = 0.0001). We concluded that noise interfered with high frequency thresholds, where all the mean values found in the experimental group were higher than those in the control group. We suggest that these data reinforce the importance of studying high frequencies, even with normal conventional audiometry in the early detection of noise-induced hearing loss.

  5. Conventional Audiometry, Extended High-Frequency Audiometry, and DPOAE for Early Diagnosis of NIHL.

    Science.gov (United States)

    Mehrparvar, Amir Houshang; Mirmohammadi, Seyyed Jalil; Davari, Mohammad Hossein; Mostaghaci, Mehrdad; Mollasadeghi, Abolfazl; Bahaloo, Maryam; Hashemi, Seyyed Hesam

    2014-01-01

    Noise most frequently affects hearing system, as it may typically cause a bilateral, progressive sensorineural hearing loss at high frequencies. This study was designed to compare three different methods to evaluate noise-induced hearing loss (conventional audiometry, high-frequency audiometry, and distortion product otoacoustic emission). This was a cross-sectional study. Data was analyzed by SPSS (ver. 19) using chi square, T test and repeated measures analysis. Study samples were workers from tile and ceramic industry. We found that conventional audiometry, extended high-frequency audiometry, low-tone distortion product otoacoustic emission and high-tone distortion product otoacoustic emission had abnormal findings in 29 %, 69 %, 22 %, and 52 % of participants. Most frequently affected frequencies were 4000 and 6000Hz in conventional audiometry, and 14000 and 16000 in extended high-frequency audiometry. Extended high-frequency audiometry was the most sensitive test for detection of hearing loss in workers exposed to hazardous noise compared with conventional audiometry and distortion product otoacoustic.

  6. The high frequency characteristics of laser reflection and visible light during solid state disk laser welding

    Science.gov (United States)

    Gao, Xiangdong; You, Deyong; Katayama, Seiji

    2015-07-01

    Optical properties are related to weld quality during laser welding. Visible light radiation generated from optical-induced plasma and laser reflection is considered a key element reflecting weld quality. An in-depth analysis of the high-frequency component of optical signals is conducted. A combination of a photoelectric sensor and an optical filter helped to obtain visible light reflection and laser reflection in the welding process. Two groups of optical signals were sampled at a high sampling rate (250 kHz) using an oscilloscope. Frequencies in the ranges 1-10 kHz and 10-125 kHz were investigated respectively. Experimental results showed that there was an obvious correlation between the high-frequency signal and the laser power, while the high-frequency signal was not sensitive to changes in welding speed. In particular, when the defocus position was changed, only a high frequency of the visible light signal was observed, while the high frequency of the laser reflection signal remained unchanged. The basic correlation between optical features and welding status during the laser welding process is specified, which helps to provide a new research focus for investigating the stability of welding status.

  7. Occupational Noise Exposure, Bilateral High-Frequency Hearing Loss, and Blood Pressure.

    Science.gov (United States)

    Gan, Wen Qi; Mannino, David M

    2017-11-13

    The aim of this study was to investigate the relationships between occupational noise exposure and blood pressure using self-reported occupational exposure and bilateral high-frequency hearing loss. This study included 4548 participants aged 20 to 69 years from the National Health and Nutrition Examination Survey 1999 to 2004. On the basis of self-reported exposure status, participants were divided into the current, former, or never exposed groups. Bilateral high-frequency hearing loss was defined as the average high-frequency hearing threshold at least 25 dB in both ears. The currently exposed participants had slightly increased diastolic blood pressure compared with those never exposed. Among previously exposed participants, those with bilateral high-frequency hearing loss had increased systolic blood pressure, heart rate, and the prevalence of hypertension compared with those with normal high-frequency hearing. Although there were some significant results, the evidence was not consistent to support the associations between occupational noise exposure and blood pressure.

  8. Phenotypic and molecular assessment of seven patients with 6p25 deletion syndrome: Relevance to ocular dysgenesis and hearing impairment

    Directory of Open Access Journals (Sweden)

    Ritch Robert

    2004-06-01

    Full Text Available Abstract Background Thirty-nine patients have been described with deletions involving chromosome 6p25. However, relatively few of these deletions have had molecular characterization. Common phenotypes of 6p25 deletion syndrome patients include hydrocephalus, hearing loss, and ocular, craniofacial, skeletal, cardiac, and renal malformations. Molecular characterization of deletions can identify genes that are responsible for these phenotypes. Methods We report the clinical phenotype of seven patients with terminal deletions of chromosome 6p25 and compare them to previously reported patients. Molecular characterization of the deletions was performed using polymorphic marker analysis to determine the extents of the deletions in these seven 6p25 deletion syndrome patients. Results Our results, and previous data, show that ocular dysgenesis and hearing impairment are the two most highly penetrant phenotypes of the 6p25 deletion syndrome. While deletion of the forkhead box C1 gene (FOXC1 probably underlies the ocular dysgenesis, no gene in this region is known to be involved in hearing impairment. Conclusions Ocular dysgenesis and hearing impairment are the two most common phenotypes of 6p25 deletion syndrome. We conclude that a locus for dominant hearing loss is present at 6p25 and that this locus is restricted to a region distal to D6S1617. Molecular characterization of more 6p25 deletion patients will aid in refinement of this locus and the identification of a gene involved in dominant hearing loss.

  9. Polymorphism of angiotensin converting enzyme (insertion/deletion ...

    Indian Academy of Sciences (India)

    across ethnic groups (Agarwal et al. 2004; Patkar et al. 2009). ∗For correspondence. E-mail: icmrrcdi@hub.nic.in. and determines genetic susceptibility to various forms of car- diovascular disease. Northeast India is inhabited by people of diverse population groups with a variable prevalence of hypertension (Hazarika et al.

  10. Angiotensin-converting enzyme insertion/deletion polymorphism ...

    African Journals Online (AJOL)

    The remaining 6 articles were included in the combined analysis12-17. A The flow chart summarizing the study selection process is shown in Figure 1. Included studies were all performed in Chi- na,Japan or Korea. All studies were in agreement ...

  11. Constitutional and mosaic large NF1 gene deletions in neurofibromatosis type 1.

    OpenAIRE

    Rasmussen, S. A.; Colman, S. D.; Ho, V.T.; Abernathy, C R; Arn, P H; Weiss, L; Schwartz, C.; Saul, R A; Wallace, M. R.

    1998-01-01

    A set of neurofibromatosis type 1 (NF1) patients was screened for large NF1 gene deletions by comparing patient and parent genotypes at 10 intragenic polymorphic loci. Of 67 patient/parent sets (47 new mutation patients and 20 familial cases), five (7.5%) showed loss of heterozygosity (LOH), indicative of NF1 gene deletion. These five patients did not have severe NF1 manifestations, mental retardation, or dysmorphic features, in contrast to previous reports of large NF1 deletions. All five de...

  12. Design and Measurement of Planar Toroidal Transformers for Very High Frequency Power Applications

    DEFF Research Database (Denmark)

    Knott, Arnold; Pejtersen, Jens

    2012-01-01

    -core toroidal transformer configuration for use in very high frequency power conversion applications. Two prototype transformers (10:10 and 12:12) have been implemented using conventional four layer printed circuit board technology. The transformers have been characterized by two port Z-parameters, which have...... power converters for very high frequencies. The magnetic coupling factor of both transformers is approx. 60 % and the mutual coupling inductance is dominant up to a frequency of 50 MHz.......The quest for higher power density has led to research of very high frequency (30-300 MHz) power converters. Magnetic components based on ferrite cores have limited application within this frequency range due to increased core loss. Air-core magnetics is a viable alternative as they do not exhibit...

  13. High-frequency phosphorus and nitrate measurements for improved statutory water quality monitoring and management

    Science.gov (United States)

    Bieroza, Magdalena

    2017-04-01

    High-frequency nutrient (phosphorus and nitrogen) monitoring using wet-chemistry analysers and optical sensors has revolutionised the collection of biogeochemical data from streams, rivers and lakes. Matching the nutrient measurement time with timescales of hydrological responses has revealed biogeochemical patterns and nutrient hydrological responses not observed previously. Capturing a wider range of nutrient concentrations compared to traditional coarse resolution sampling enables more accurate estimation of mean concentrations and loads and thus improved water body classification. However, to date the scientific insights from the high-frequency nutrient monitoring studies have not been translated into policy and operational responses. The pertinent question is where and how often to measure nutrients to satisfy statutory monitoring requirements for the Water Framework Directive and the Nitrates Directive. Therefore this paper discusses how the reduced data uncertainty and improved process understanding obtained with the high-frequency measurements can improve statutory nutrient monitoring, using case studies from England and Sweden.

  14. High-frequency homogenization of zero frequency stop band photonic and phononic crystals

    CERN Document Server

    Antonakakis, Tryfon; Guenneau, Sebastien

    2013-01-01

    We present an accurate methodology for representing the physics of waves, for periodic structures, through effective properties for a replacement bulk medium: This is valid even for media with zero frequency stop-bands and where high frequency phenomena dominate. Since the work of Lord Rayleigh in 1892, low frequency (or quasi-static) behaviour has been neatly encapsulated in effective anisotropic media. However such classical homogenization theories break down in the high-frequency or stop band regime. Higher frequency phenomena are of significant importance in photonics (transverse magnetic waves propagating in infinite conducting parallel fibers), phononics (anti-plane shear waves propagating in isotropic elastic materials with inclusions), and platonics (flexural waves propagating in thin-elastic plates with holes). Fortunately, the recently proposed high-frequency homogenization (HFH) theory is only constrained by the knowledge of standing waves in order to asymptotically reconstruct dispersion curves an...

  15. Advanced waveforms and frequency with spinal cord stimulation: burst and high-frequency energy delivery.

    Science.gov (United States)

    Pope, Jason E; Falowski, Steven; Deer, Tim R

    2015-07-01

    In recent years, software development has been key to the next generation of neuromodulation devices. In this review, we will describe the new strategies for electrical waveform delivery for spinal cord stimulation. A systematic literature review was performed using bibliographic databases, limited to the English language and human data, between 2010 and 2014. The literature search yielded three articles on burst stimulation and four articles on high-frequency stimulation. High-frequency and burst stimulation may offer advantages over tonic stimulation, as data suggest improved patient tolerance, comparable increase in function and possible success with a subset of patients refractory to tonic spinal cord stimulation. High-frequency and burst stimulation are new ways to deliver energy to the spinal cord that may offer advantages over tonic stimulation. These may offer new salvage strategies to mitigate spinal cord stimulation failure and improve cost-effectiveness by reducing explant rate.

  16. Control of drug release from capsules using high frequency energy transmission systems.

    Science.gov (United States)

    Gröning, R; Bensmann, H; Müller, R S

    2008-11-19

    In the present investigations new drug delivery systems have been developed, which are controlled by a computer and a high frequency energy transmission system. The capsules consist of a drug reservoir, a high frequency receiver, a gas generating section and a piston to pump a drug solution or drug suspension out of the reservoir. Mechanical energy is generated inside the capsule through electrolysis, if a 27 MHz high frequency field is in resonance with the receiver inside the capsule. Two different miniaturised oscillatory circuits were constructed, which act as the receivers in the capsules. Tramadol was used in release experiments as a model drug. Delayed and pulsed release profiles were obtained. A computer-controlled system was constructed, in which the programmed release profiles are compared with the actual release of the drug.

  17. Fourier Spot Volatility Estimator: Asymptotic Normality and Efficiency with Liquid and Illiquid High-Frequency Data

    Science.gov (United States)

    2015-01-01

    The recent availability of high frequency data has permitted more efficient ways of computing volatility. However, estimation of volatility from asset price observations is challenging because observed high frequency data are generally affected by noise-microstructure effects. We address this issue by using the Fourier estimator of instantaneous volatility introduced in Malliavin and Mancino 2002. We prove a central limit theorem for this estimator with optimal rate and asymptotic variance. An extensive simulation study shows the accuracy of the spot volatility estimates obtained using the Fourier estimator and its robustness even in the presence of different microstructure noise specifications. An empirical analysis on high frequency data (U.S. S&P500 and FIB 30 indices) illustrates how the Fourier spot volatility estimates can be successfully used to study intraday variations of volatility and to predict intraday Value at Risk. PMID:26421617

  18. Monitoring uniform and localized corrosion in reinforced mortar using high-frequency guided longitudinal wages

    Science.gov (United States)

    Ervin, Benjamin L.; Reis, Henrique; Bernhard, Jennifer T.; Kuchma, Daniel A.

    2008-03-01

    High-frequency guided longitudinal waves have been used in a through-transmission arrangement to monitor reinforced mortar specimens undergoing both accelerated uniform and localized corrosion. High-frequency guided longitudinal waves were chosen because they have the fastest propagation velocity and lowest theoretical attenuation for the rebar/mortar system. This makes the modes easily discernible and gives them the ability to travel over long distances. The energy of the high-frequency longitudinal waves is located primarily in the center of the rebar, leading to less leakage into the surrounding mortar. The results indicate that the guided mechanical waves are sensitive to both forms of corrosion attack in the form of attenuation, with less sensitivity at higher frequencies. Also promising is the ability to discern uniform corrosion from localized corrosion in a through-transmission arrangement by examination of the frequency domain.

  19. High-frequency radar observations of PMSE modulation by radio heating

    Science.gov (United States)

    Senior, Andrew; Rietveld, Michael; Mahmoudian, Alireza; La Hoz, Cesar; Kosch, Michael; Scales, Wayne; Pinedo, Henry

    The first observations using high-frequency (8 MHz) radar of modulation of polar mesospheric summer echoes (PMSE) by radio heating of the ionosphere are presented. The experiment was performed at the EISCAT facility near Tromsø, Norway. The observations are compared with simultaneous radar measurements at 224 MHz and with a model of the dusty plasma response to electron heating. Agreement between the model and observations is good considering technical limitations on the 8 MHz radar measurements. Predictions made about the response of high-frequency PMSE to heating where dust charging dominates over diffusion, opposite to the situation at very high-frequencies are confirmed. Suggestions are made about improving the 8 MHz observations to overcome the current limitations.

  20. Development of High-frequency Soft Magnetic Materials for Power Electronics

    Directory of Open Access Journals (Sweden)

    LIU Jun-chang

    2017-05-01

    Full Text Available The new requirements of high-frequency magnetic properties are put forward for electronic components with the rapid development of power electronics industry and the use of new electromagnetic materials. The properties of magnetic core, which is the key unit of electronic components, determine the performance of electronic components directly. Therefore, it's necessary to study the high-frequency soft magnetic materials. In this paper, the development history of four types of soft magnetic materials was reviewed. The advantages and disadvantages of each kind of soft magnetic materials and future development trends were pointed out. The emphases were placed on the popular soft magnetic composite materials in recent years. The tendency is to develop high-frequency soft magnetic composite materials with the particle size controllable, uniform coating layer on the core and a mass production method from laboratory to industrialization.

  1. High frequency mass transfer responses with polyaniline modified electrodes by using new ac-electrogravimetry device

    Energy Technology Data Exchange (ETDEWEB)

    Torres, R. [Escuela de Ingenieria de Antioquia Calle 25 Sur No. 42-73, Envigado (Colombia); Jimenez, Y.; Arnau, A. [Departamento Ingenieria Electronica, ETSI de Telecomunicacion, Universidad Politecnica de Valencia, Camino de Vera s/n, C.P. 46022, Valencia (Spain); Gabrielli, C.; Joiret, S. [CNRS, UPR 15 du CNRS, Laboratoire Interfaces et Systemes Electrochimiques-LISE, 4, place Jussieu, 75005 Paris (France)] [UPMC, Universite Pierre et Marie Curie-Paris 6, Laboratoire Interfaces et Systemes Electrochimiques-LISE, 4, place Jussieu, 75005 Paris (France); Perrot, H., E-mail: hubert.perrot@upmc.f [CNRS, UPR 15 du CNRS, Laboratoire Interfaces et Systemes Electrochimiques-LISE, 4, place Jussieu, 75005 Paris (France)] [UPMC, Universite Pierre et Marie Curie-Paris 6, Laboratoire Interfaces et Systemes Electrochimiques-LISE, 4, place Jussieu, 75005 Paris (France); To, T.K.L.; Wang, X. [CNRS, UPR 15 du CNRS, Laboratoire Interfaces et Systemes Electrochimiques-LISE, 4, place Jussieu, 75005 Paris (France)] [UPMC, Universite Pierre et Marie Curie-Paris 6, Laboratoire Interfaces et Systemes Electrochimiques-LISE, 4, place Jussieu, 75005 Paris (France)

    2010-08-30

    For many years, polyaniline films have appeared to be one of the most studied conducting polymers. At the same time, ac-electrogravimetry has been used as a powerful technique for different polymer films but in general for slow perturbation rates. Two reasons for that: on the one hand, high frequency mass transfer responses are not expected and on the other hand, the electronic interfaces dedicated for ac-electrogravimetry are not prepared to follow, without distortion, high rate frequency shifts, faster than a few hertz. This paper shows that high ionic transfer responses can be detected by using a new ac-electrogravimetry concept. The experiments conducted with PANI tried to verify whether high frequency responses in conducting polymers are possible or not. The main interest of the new device is to reach the high frequency values directly and to demonstrate an ionic transfer contribution at 1 kHz which was not predicted with old systems.

  2. High frequency hearing thresholds and product distortion otoacoustic emissions in cystic fibrosis patients,

    Directory of Open Access Journals (Sweden)

    Lucia Bencke Geyer

    2015-12-01

    Full Text Available ABSTRACT INTRODUCTION: The treatment of patients with cystic fibrosis involves the use of ototoxic drugs, mainly aminoglycoside antibiotics. Due to the use of these drugs, fibrocystic patients are at risk of developing hearing loss. OBJECTIVE: To evaluate the hearing of patients with cystic fibrosis by High Frequency Audiometry and Distortion Product Otoacoustic Emissions. METHODS: Cross-sectional study. The study group consisted of 39 patients (7-20 years of age with cystic fibrosis and a control group of 36 individuals in the same age group without otologic complaints, with normal audiometric thresholds and type A tympanometric curves. High Frequency Audiometry and Distortion Product Otoacoustic Emissions tests were conducted. RESULTS: The study group had significantly higher thresholds at 250, 1000, 8000, 9000, 10,000, 12,500, and 16,000 Hz (p = 0.004 as well as higher prevalence of otoacoustic emission alterations at 1000 and 6000 Hz (p = 0.001, with significantly lower amplitudes at 1000, 1400, and 6000 Hz. There was a significant association between alterations in hearing thresholds in High Frequency Audiometry with the number of courses of aminoglycosides administered (p = 0.005. Eighty-three percent of patients who completed more than ten courses of aminoglycosides had hearing loss in High Frequency Audiometry. CONCLUSION: A significant number of patients with cystic fibrosis who received repeated courses of aminoglycosides showed alterations in High Frequency Audiometry and Distortion Product Otoacoustic Emissions. The implementation of ten or more aminoglycoside cycles was associated with alterations in High Frequency Audiometry.

  3. Hearing thresholds at high frequency in patients with cystic fibrosis: a systematic review.

    Science.gov (United States)

    Caumo, Debora T M; Geyer, Lúcia B; Teixeira, Adriane R; Barreto, Sérgio S M

    High-frequency audiometry may contribute to the early detection of hearing loss caused by ototoxic medications. Many ototoxic drugs are widely used in the treatment of patients with cystic fibrosis. Early detection of hearing loss should allow known harmful drugs to be identified before the damage affects speech frequencies. The damage caused by ototoxicity is irreversible, resulting in important social and psychological consequences. In children, hearing loss, even when restricted to high frequencies, can affect the development of language. To investigate the efficacy and effectiveness of hearing monitoring through high-frequency audiometry in pediatric patients with cystic fibrosis. Electronic databases PubMed, MedLine, Web of Science and LILACS were searched, from January to November 2015. The selected studies included those in which high-frequency audiometry was performed in patients with cystic fibrosis, undergoing treatment with ototoxic drugs and published in Portuguese, English and Spanish. The GRADE system was chosen for the evaluation of the methodological quality of the articles. During the search process carried out from January 2015 to November 2015, 512 publications were identified, of which 250 were found in PubMed, 118 in MedLine, 142 in Web of Science and 2 in LILACS. Of these, nine articles were selected. The incidence of hearing loss was identified at high frequencies in cystic fibrosis patients without hearing complaints. It is assumed that high-frequency audiometry can be an early diagnostic method to be recommended for hearing investigation of patients at risk of ototoxicity. Copyright © 2016 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  4. High frequency hearing thresholds and product distortion otoacoustic emissions in cystic fibrosis patients.

    Science.gov (United States)

    Geyer, Lucia Bencke; Menna Barreto, Sergio Saldanha; Weigert, Liese Loureiro; Teixeira, Adriane Ribeiro

    2015-01-01

    The treatment of patients with cystic fibrosis involves the use of ototoxic drugs, mainly aminoglycoside antibiotics. Due to the use of these drugs, fibrocystic patients are at risk of developing hearing loss. To evaluate the hearing of patients with cystic fibrosis by High Frequency Audiometry and Distortion Product Otoacoustic Emissions. Cross-sectional study. The study group consisted of 39 patients (7-20 years of age) with cystic fibrosis and a control group of 36 individuals in the same age group without otologic complaints, with normal audiometric thresholds and type A tympanometric curves. High Frequency Audiometry and Distortion Product Otoacoustic Emissions tests were conducted. The study group had significantly higher thresholds at 250, 1000, 8000, 9000, 10,000, 12,500, and 16,000Hz (p=0.004) as well as higher prevalence of otoacoustic emission alterations at 1000 and 6000Hz (p=0.001), with significantly lower amplitudes at 1000, 1400, and 6000Hz. There was a significant association between alterations in hearing thresholds in High Frequency Audiometry with the number of courses of aminoglycosides administered (p=0.005). Eighty-three percent of patients who completed more than ten courses of aminoglycosides had hearing loss in High Frequency Audiometry. A significant number of patients with cystic fibrosis who received repeated courses of aminoglycosides showed alterations in High Frequency Audiometry and Distortion Product Otoacoustic Emissions. The implementation of ten or more aminoglycoside cycles was associated with alterations in High Frequency Audiometry. Copyright © 2015 Associação Brasileira de Otorrinolaringologia e Cirurgia Cérvico-Facial. Published by Elsevier Editora Ltda. All rights reserved.

  5. Accumulated Source Imaging of Brain Activity with Both Low and High-Frequency Neuromagnetic Signals

    Directory of Open Access Journals (Sweden)

    Jing eXiang

    2014-05-01

    Full Text Available Recent studies have revealed the importance of high-frequency brain signals (>70 Hz. One challenge of high-frequency signal analysis is that the size of time-frequency representation of high-frequency brain signals could be larger than 1 terabytes (TB, which is beyond the upper limits of a typical computer workstation’s memory (<196 GB. The aim of the present study is to develop a new method to provide greater sensitivity in detecting high-frequency magnetoencephalography (MEG signals in a single automated and versatile interface, rather than the more traditional, time-intensive visual inspection methods, which may take up to several days. To address the aim, we developed a new method, accumulated source imaging, defined as the volumetric summation of source activity over a period of time. This method analyzes signals in both low- (1~70 Hz and high-frequency (70~200 Hz ranges at source levels. To extract meaningful information from MEG signals at sensor space, the signals were decomposed to channel-cross-channel matrix (CxC representing the spatiotemporal patterns of every possible sensor-pair. A new algorithm was developed and tested by calculating the optimal CxC and source location-orientation weights for volumetric source imaging, thereby minimizing multi-source interference and reducing computational cost. The new method was implemented in C/C++ and tested with MEG data recorded from clinical epilepsy patients. The results of experimental data demonstrated that accumulated source imaging could effectively summarize and visualize MEG recordings within 12.7 hours by using approximately 10 GB of computer memory. In contrast to the conventional method of visually identifying multi-frequency epileptic activities that traditionally took 2-3 days and used 1-2 TB storage, the new approach can quantify epileptic abnormalities in both low- and high-frequency ranges at source levels, using much less time and computer memory.

  6. Hearing thresholds at high frequency in patients with cystic fibrosis: a systematic review

    Directory of Open Access Journals (Sweden)

    Debora T.M. Caumo

    Full Text Available Abstract Introduction: High-frequency audiometry may contribute to the early detection of hearing loss caused by ototoxic medications. Many ototoxic drugs are widely used in the treatment of patients with cystic fibrosis. Early detection of hearing loss should allow known harmful drugs to be identified before the damage affects speech frequencies. The damage caused by ototoxicity is irreversible, resulting in important social and psychological consequences. In children, hearing loss, even when restricted to high frequencies, can affect the development of language. Objective: To investigate the efficacy and effectiveness of hearing monitoring through high-frequency audiometry in pediatric patients with cystic fibrosis. Methods: Electronic databases PubMed, MedLine, Web of Science and LILACS were searched, from January to November 2015. The selected studies included those in which high-frequency audiometry was performed in patients with cystic fibrosis, undergoing treatment with ototoxic drugs and published in Portuguese, English and Spanish. The GRADE system was chosen for the evaluation of the methodological quality of the articles. Results: During the search process carried out from January 2015 to November 2015, 512 publications were identified, of which 250 were found in PubMed, 118 in MedLine, 142 in Web of Science and 2 in LILACS. Of these, nine articles were selected. Conclusion: The incidence of hearing loss was identified at high frequencies in cystic fibrosis patients without hearing complaints. It is assumed that high-frequency audiometry can be an early diagnostic method to be recommended for hearing investigation of patients at risk of ototoxicity.

  7. Improving sensitivity of residual current transformers to high frequency earth fault currents

    Directory of Open Access Journals (Sweden)

    Czapp Stanislaw

    2017-09-01

    Full Text Available For protection against electric shock in low voltage systems residual current devices are commonly used. However, their proper operation can be interfered when high frequency earth fault current occurs. Serious hazard of electrocution exists then. In order to detect such a current, it is necessary to modify parameters of residual current devices, especially the operating point of their current transformer. The authors proposed the modification in the structure of residual current devices. This modification improves sensitivity of residual current devices when high frequency earth fault current occurs. The test of the modified residual current device proved that the authors’ proposition is appropriate.

  8. A study and classification of non-linear high frequency ionospheric instabilities by coupled mode theory.

    Science.gov (United States)

    Harker, K. J.

    1972-01-01

    Two basic high-frequency ionospheric instabilities are discussed - i.e., the three-wave parametric interaction, and the oscillating two-stream instability. In the parametric instability, the ion-acoustic wave has a complex frequency, whereas in the oscillating two-stream instability the ion-acoustic frequency is purely imaginary. The parametric instability is shown to be the only one whose threshold depends on the ion collision frequency. A coupled-mode theory is proposed which permits study and classification of high-frequency instabilities on a unified basis.

  9. Some general effects of strong high-frequency excitation: stiffening, biasing, and smoothening

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    2002-01-01

    that can be modeled by a finite number of second order ordinary differential equations, generally nonlinear, with periodically oscillating excitation terms of high frequency and small amplitude. The results should be useful for understanding the effects in question in a broader perspective than is possible......Mechanical high-frequency (HF) excitation provides a working principle behind many industrial and natural applications and phenomena. This paper concerns three particular effects of HF excitation, that may change the apparent characteristics of mechanical systems: 1) stiffening, by which...

  10. Theta-associated high-frequency oscillations (110–160 Hz) in the hippocampus and neocortex

    OpenAIRE

    Tort, Adriano B. L.; Scheffer-Teixeira, Robson; Souza, Bryan C.; Draguhn, Andreas; Brankacˇk, Jurij

    2013-01-01

    TORT, A. B. L. ; SCHEFFER-TEIXEIRA, R ; Souza, B.C. ; DRAGUHN, A. ; BRANKACK, J. . Theta-associated high-frequency oscillations (110-160 Hz) in the hippocampus and neocortex. Progress in Neurobiology , v. 100, p. 1-14, 2013. We review recent evidence for a novel type of fast cortical oscillatory activity that occurs circumscribed between 110 and 160 Hz, which we refer to as high-frequency oscillations (HFOs). HFOs characteristically occur modulated by theta phase in the hippocampus a...

  11. High-frequency programmable acoustic wave device realized through ferroelectric domain engineering

    Science.gov (United States)

    Ivry, Yachin; Wang, Nan; Durkan, Colm

    2014-03-01

    Surface acoustic wave devices are extensively used in contemporary wireless communication devices. We used atomic force microscopy to form periodic macroscopic ferroelectric domains in sol-gel deposited lead zirconate titanate, where each ferroelectric domain is composed of many crystallites, each of which contains many microscopic ferroelastic domains. We examined the electro-acoustic characteristics of the apparatus and found a resonator behavior similar to that of an equivalent surface or bulk acoustic wave device. We show that the operational frequency of the device can be tailored by altering the periodicity of the engineered domains and demonstrate high-frequency filter behavior (>8 GHz), allowing low-cost programmable high-frequency resonators.

  12. Determining of the electric field strength using high frequency broadband measurements

    OpenAIRE

    Vulević, Branislav D.

    2017-01-01

    Exposure of humans to electromagnetic fields of high frequency (above 100 kHz), i.e. radiofrequency radiation from the modern wireless systems, today inevitable is. The purpose of this paper is to highlight the importance of broadband measurements of the electric field of high frequency in order to fast and reliable assessment of human exposure. A practical method of ‘in situ’ measurement the electric field intensity which is related to the frequency range of 3 MHz to 18 GHz, is provided.

  13. An induction motor model for high-frequency torsional vibration analysis

    Science.gov (United States)

    Widdle, R. D.; Krousgrill, C. M.; Sudhoff, S. D.

    2006-03-01

    High-frequency torsional oscillations of a 50 horsepower (hp) induction motor are investigated up to approximately 30 kHz. It is experimentally determined that torsional oscillations, due to the switching harmonics of the motor drive, contribute significantly to the torsional oscillation of the output shaft. Two torsional vibration models are developed. One model assumes the rotor to be rigid, while the other has a compliant rotor. The compliant model allows for greater transmission of high-frequency oscillations, and a better prediction of the measured output shaft vibration.

  14. Effective market influence. An effect chain analysis of NUTEK`s high-frequency lighting campaign

    Energy Technology Data Exchange (ETDEWEB)

    Goeransson, C.; Faugert, S. [SIPU Utvaerdering, Stockholm (Sweden); Baeckman, B.; Arndt, J. [B2B AB, Stockholm (Sweden)

    1994-12-31

    This report is an evaluation of NUTEK`s `Better lighting and more energy-efficient high-frequency fluorescent tube luminaries` campaign. It is concerned with the ways in which NUTEK can influence the spread and use of high-frequency (HF) lighting devices. It also shows that NUTEK actually has affected (contributed to) development in the area. The report analyses and quantifies (as far as possible) how much NUTEK has influenced the various parties concerned in the sector, their attitudes and their actions. 14 figs, 5 tabs

  15. A Realized Variance for the Whole Day Based on Intermittent High-Frequency Data

    DEFF Research Database (Denmark)

    Hansen, Peter Reinhard; Lunde, Asger

    2005-01-01

    We consider the problem of deriving an empirical measure of daily integrated variance (IV) in the situation where high-frequency price data are unavailable for part of the day. We study three estimators in this context and characterize the assumptions that justify their use. We show that the opti......We consider the problem of deriving an empirical measure of daily integrated variance (IV) in the situation where high-frequency price data are unavailable for part of the day. We study three estimators in this context and characterize the assumptions that justify their use. We show...

  16. High-frequency impedance of small-angle tapers and collimators

    Directory of Open Access Journals (Sweden)

    G. Stupakov

    2010-10-01

    Full Text Available Collimators and transitions in accelerator vacuum chambers often include small-angle tapering to lower the wakefields generated by the beam. While the low-frequency impedance is well described by Yokoya’s formula (for axisymmetric geometry, much less is known about the behavior of the impedance in the high-frequency limit. In this paper we develop an analytical approach to the high-frequency regime for round collimators and tapers. Our analytical results are compared with computer simulations using the code ECHO.

  17. A Pitch Extraction Method with High Frequency Resolution for Singing Evaluation

    Science.gov (United States)

    Takeuchi, Hideyo; Hoguro, Masahiro; Umezaki, Taizo

    This paper proposes a pitch estimation method suitable for singing evaluation incorporable in KARAOKE machines. Professional singers and musicians have sharp hearing for music and singing voice. They recognize that singer's voice pitch is “a little off key” or “be in tune”. In the same way, the pitch estimation method that has high frequency resolution is necessary in order to evaluate singing. This paper proposes a pitch estimation method with high frequency resolution utilizing harmonic characteristic of autocorrelation function. The proposed method can estimate a fundamental frequency in the range 50 ∼ 1700[Hz] with resolution less than 3.6 cents in light processing.

  18. Self-oscillating Galvanic Isolated Bidirectional Very High Frequency DC-DC Converter

    DEFF Research Database (Denmark)

    Pedersen, Jeppe Arnsdorf; Madsen, Mickey Pierre; Knott, Arnold

    2015-01-01

    This paper describes a galvanic isolated bidirectional Very High Frequency (VHF = 30 MHz - 300MHz) ClassE converter. The reason for increasing the switching frequency is to minimize the passive components in the converter. To make the converter topology bidirectional the rectifier has to be synch......This paper describes a galvanic isolated bidirectional Very High Frequency (VHF = 30 MHz - 300MHz) ClassE converter. The reason for increasing the switching frequency is to minimize the passive components in the converter. To make the converter topology bidirectional the rectifier has...

  19. Identification of the Parameters of the High-Frequency Equivalent Circuit of PM Synchronous Motor based on Genetic Algorithm

    Science.gov (United States)

    Ito, Kouhei; Sato, Yasuyuki; Zanma, Tadanao; Doki, Shinji; Ishida, Muneaki

    This paper presents an identification technique of parameters of a high frequency equivalent circuit of permanent magnet synchronous motors (PMSM) driven by a PWM inverter. The high frequency oscillatory currents such as leakage current to the motor frame (common-mode current) and high frequency oscillatory line current (normal-mode current), are generated by switching instants of inverter transistors. The parameters of the high frequency equivalent circuit of PMSM which can simulate the oscillating current are identified by means of genetic algorithm. It is shown that the high frequency equivalent circuit with identified parameters can generate the oscillating current by some simulation results.

  20. Using very high frequencies with very low lung volumes during high-frequency oscillatory ventilation to protect the immature lung. A pilot study.

    Science.gov (United States)

    González-Pacheco, N; Sánchez-Luna, M; Ramos-Navarro, C; Navarro-Patiño, N; de la Blanca, A R-S

    2016-04-01

    High-frequency oscillatory ventilation (HFOV) has been described as a rescue therapy in severe respiratory distress syndrome (RDS) with a potential protective effect in immature lungs. In recent times, HFOV combined with the use of volume guarantee (VG) strategy has demonstrated an independent effect of the frequency on tidal volume to increase carbon-dioxide (CO2) elimination. The aim of this study was to demonstrate the feasibility of using the lowest tidal volume on HFOV+VG to prevent lung damage, maintaining a constant CO2 elimination by increasing the frequency. Newborn infants with RDS on HFOV were prospectively included. After adequate and stable ventilation using a standard HFOV strategy, the tidal volume was fixed using VG and decreased while the frequency was increased to the highest possible to maintain a constant CO2 elimination. Pre- and post-PCO2, delta pressure and tidal volume obtained in each situation were compared. Twenty-three newborn infants were included. It was possible to increase the frequency while decreasing the tidal volume in all patients, maintaining a similar CO2 elimination, with a tendency to a lower mean PCO2 after reaching the highest frequency. High-frequency tidal volume was significantly lower, 2.20 ml kg(-1) before vs 1.59 ml kg(-1) at the highest frequency. It is possible to use lower delivered tidal volumes during HFOV combined with VG and higher frequencies with adequate ventilation to allow minimizing lung injury.

  1. High frequency oscillations after median nerve stimulations in healthy children and adolescents.

    Science.gov (United States)

    Zanini, Sergio; Del Piero, Ivana; Martucci, Lucia; Restuccia, Domenico

    2017-10-01

    The aim of the present research was to address somatosensory high frequency oscillations (400-800Hz) in healthy children and adolescents in comparison with healthy adults. We recorded somatosensory evoked potentials following median nerve stimulation in nineteen resting healthy children/adolescents and in nineteen resting healthy adults with eyes closed. We administered six consecutive stimulation blocks (500 sweeps each). The presynaptic component of high frequency oscillations amplitudes was smaller in healthy children/adolescents than in healthy adults (no difference between groups was found as far as the postsynaptic component was concerned). Healthy children/adolescents had smaller presynaptic component than the postsynaptic one (the postsynaptic component amplitude was 145% of the presynaptic one), while healthy adults showed the opposite (reduction of the postsynaptic component to 80% of the presynaptic one). No habituation phenomena concerning high frequency oscillation amplitudes were registered in neither healthy children/adolescents nor healthy adults. These findings suggest that healthy children/adolescents present with significantly different pattern of somatosensory high frequency oscillations compared with healthy adults' ones. This different pattern is reasonably expression of higher cortical excitability of the developing brain cortex. Copyright © 2017 ISDN. Published by Elsevier Ltd. All rights reserved.

  2. Spot Variance Path Estimation and its Application to High Frequency Jump Testing

    NARCIS (Netherlands)

    Bos, C.S.; Janus, P.; Koopman, S.J.

    2012-01-01

    This paper considers spot variance path estimation from datasets of intraday high-frequency asset prices in the presence of diurnal variance patterns, jumps, leverage effects, and microstructure noise. We rely on parametric and nonparametric methods. The estimated spot variance path can be used to

  3. Online BCI implementation of high-frequency phase modulated visual stimuli

    NARCIS (Netherlands)

    Garcia Molina, G.; Danhua, Z.; Aarts, R.M.; Mihajlovic, V.

    2011-01-01

    Brain computer interfaces (BCI) that use the steady-state-visual-evoked-potential (SSVEP) as neural source, offer two main advantages over other types of BCIs: shorter calibration times and higher information transfer rates. SSVEPs elicited by high frequency (larger than30 Hz) repetitive visual

  4. Enhanced high-frequency microwave absorption of Fe3O4 architectures based on porous nanoflake

    DEFF Research Database (Denmark)

    Wang, Xiaoliang; Liu, Yanguo; Han, Hongyan

    2017-01-01

    Hierarchical Fe3O4 architectures assembled with porous nanoplates (p-Fe3O4) were synthesized. Due to the strong shape anisotropy of the nanoplates, the p-Fe3O4 exhibits increased microwave resonance towards high frequency range. The improved microwave absorption properties of the p-Fe3O4, including...

  5. Deriving animal behaviour from high-frequency GPS: tracking cows in open and forested habitat

    NARCIS (Netherlands)

    Weerd, de N.; Langevelde, van F.; Oeveren, van H.; Nolet, B.A.; Kölzsch, A.; Prins, H.H.T.; Boer, de W.F.

    2015-01-01

    The increasing spatiotemporal accuracy of Global Navigation Satellite Systems (GNSS) tracking systems opens the possibility to infer animal behaviour from tracking data.We studied the relationship between high-frequency GNSS data and behaviour, aimed at developing an easily interpretable

  6. High Frequency Synchrony in the Cerebellar Cortex during Goal Directed Movements

    Directory of Open Access Journals (Sweden)

    Jonathan David Groth

    2015-07-01

    Full Text Available The cerebellum is involved in sensory-motor integration and cognitive functions. The origin and function of the field potential oscillations in the cerebellum, especially in the high frequencies, have not been explored sufficiently. The primary objective of this study was to investigate the spatio-temporal characteristics of high frequency field potentials (150-350Hz in the cerebellar cortex in a behavioral context. To this end, we recorded from the paramedian lobule in rats using micro electro-corticogram (µ-ECoG electrode arrays while the animal performed a lever press task using the forelimb. The phase synchrony analysis shows that the high frequency oscillations recorded at multiple points across the paramedian cortex episodically synchronize immediately before and desynchronize during the lever press. The electrode contacts were grouped according to their temporal course of phase synchrony around the time of lever press. Contact groups presented patches with slightly stronger synchrony values in the medio-lateral direction, and did not appear to form parasagittal zones. The size and location of these patches on the cortical surface are in agreement with the sensory evoked granular layer patches originally reported by Welker’s lab (Shambes, 1978. Spatiotemporal synchrony of high frequency field potentials has not been reported at such large-scales previously in the cerebellar cortex.

  7. Planck 2015 results: VII. High Frequency Instrument data processing: Time-ordered information and beams

    DEFF Research Database (Denmark)

    Adam, R.; Ade, P. A R; Aghanim, N.

    2016-01-01

    The Planck High Frequency Instrument (HFI) has observed the full sky at six frequencies (100, 143, 217, 353, 545, and 857 GHz) in intensity and at four frequencies in linear polarization (100, 143, 217, and 353 GHz). In order to obtain sky maps, the time-ordered information (TOI) containing the d...

  8. Effective properties of mechanical systems under high-frequency excitation at multiple frequencies

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    2008-01-01

    Effects of strong high-frequency excitation at multiple frequencies (multi-HFE) are analyzed for a class of generally nonlinear systems. The effects are illustrated for a simple pendulum system with a vibrating support, and for a parametrically excited flexible beam. For the latter, theoretical...

  9. Computing effective properties of nonlinear structures exposed to strong high-frequency loading at multiple frequencies

    DEFF Research Database (Denmark)

    Thomsen, Jon Juel

    2006-01-01

    Effects of strong high-frequency excitation at multiple frequencies (multi-HFE) are analyzed for a class of generally nonlinear systems. The effects are illustrated for a simple pendulum system with a vibrating support, and for a parametrically excited flexible beam. For the latter, theoretical...

  10. Mitigation of high-frequency pulsations, using Multi Bore Restriction Orifices

    NARCIS (Netherlands)

    Lier, L.J. van; Korst, H.J.C.

    2007-01-01

    In reciprocating fluid displacement systems, a trend toward high-speed machinery and application of stepless reverse-flow capacity control system is observed. Badly designed compression systems may cause excessive high-frequency noise and vibration levels, which are a risk from a structural

  11. EMC Investigation of a Very High Frequency Self-oscillating Resonant Power Converter

    DEFF Research Database (Denmark)

    Pedersen, Jeppe Arnsdorf; Knott, Arnold; Andersen, Michael A. E.

    2016-01-01

    This paper focuses on the electromagnetic compatibility (EMC) performance of a Very High Frequency (VHF) converter and how to lower the emissions. To test the EMC performance a VHF converter is implemented with a Class-E inverter and a Class-DE rectifier. The converter is designed to deliver 3 W...

  12. Regional respiratory time constants during lung recruitment in high-frequency oscillatory ventilated preterm infants

    NARCIS (Netherlands)

    Miedema, Martijn; de Jongh, Frans H.; Frerichs, Inez; van Veenendaal, Mariëtte B.; van Kaam, Anton H.

    2012-01-01

    To assess the regional respiratory time constants of lung volume changes during stepwise lung recruitment before and after surfactant treatment in high-frequency oscillatory ventilated preterm infants. A stepwise oxygenation-guided recruitment procedure was performed before and after surfactant

  13. High-frequency acoustic charge transport in GaAs nanowires

    NARCIS (Netherlands)

    Büyükköse, S.; Hernandez-Minguez, A.; Vratzov, B.; Somaschini, C.; Geelhaar, L.; Riechert, H.; van der Wiel, Wilfred Gerard; Santos, P.V.

    2014-01-01

    The oscillating piezoelectric fields accompanying surface acoustic waves are able to transport charge carriers in semiconductor heterostructures. Here, we demonstrate high-frequency (above 1 GHz) acoustic charge transport in GaAs-based nanowires deposited on a piezoelectric substrate. The short

  14. High-frequency EPR and ENDOR spectroscopy on semiconductor quantum dots

    NARCIS (Netherlands)

    Baranov, P.G.; Orlinskii, S.B.; de Mello Donega, C.|info:eu-repo/dai/nl/125593899; Schmidt, J.

    2010-01-01

    It is shown that high-frequency electron paramagnetic resonance (EPR) and electron-nuclear double resonance (ENDOR) spectroscopy are excellent tools for the investigation of the electronic properties of semiconductor quantum dots (QDs). The great attractions of these techniques are that, in contrast

  15. High-frequency field-deployable isotope analyzer for hydrological applications

    Science.gov (United States)

    Elena S.F. Berman; Manish Gupta; Chris Gabrielli; Tina Garland; Jeffrey J. McDonnell

    2009-01-01

    A high-frequency, field-deployable liquid water isotope analyzer was developed. The instrument was deployed for 4 contiguous weeks in the H. J. Andrews Experimental Forest Long-term Ecological Research site in western Oregon, where it was used for real-time measurement of the isotope ratios of precipitation and stream water during three large storm events. We were able...

  16. Tidally-modulated high frequency internal waves in Gautami-Godavari estuary, East coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Sridevi, B.; Murty, T.V.R.; Sadhuram, Y.; Sarma, V.V.S.S.; Murty, V.S.N.; Prasad, K.V.S.R.

    of Internal waves (IWs) and to infer their generation mechanism Based on the stability criteria, two High Frequency (HF) significant modes in the Internal Wave (IW) field at frequencies 96.67 cph (10 m depth) and 71.15 cph (14 m depth) have been identified...

  17. High Frequency Combustion Instabilities of LOx/CH4 Spray Flames in Rocket Engine Combustion Chambers

    NARCIS (Netherlands)

    Sliphorst, M.

    2011-01-01

    Ever since the early stages of space transportation in the 1940’s, and the related liquid propellant rocket engine development, combustion instability has been a major issue. High frequency combustion instability (HFCI) is the interaction between combustion and the acoustic field in the combustion

  18. Using high-frequency sampling to detect effects of atmospheric pollutants on stream chemistry

    Science.gov (United States)

    Stephen D. Sebestyen; James B. Shanley; Elizabeth W. Boyer

    2009-01-01

    We combined information from long-term (weekly over many years) and short-term (high-frequency during rainfall and snowmelt events) stream water sampling efforts to understand how atmospheric deposition affects stream chemistry. Water samples were collected at the Sleepers River Research Watershed, VT, a temperate upland forest site that receives elevated atmospheric...

  19. High frequency stimulation of the subthalamic nucleus is efficacious in Parkin disease

    NARCIS (Netherlands)

    Romito, Luigi M. A.; Contarino, Maria F.; Ghezzi, Daniele; Franzini, Angelo; Garavaglia, Barbara; Albanese, Alberto

    2005-01-01

    High frequency stimulation (HFS) of the subthalamic nucleus (STN) is an efficacious symptomatic treatment for Parkinson's disease. We have analysed the genetic status of a series of consecutive parkinsonian patients implanted for STN HFS and compared the outcome of five carrying mutations in the

  20. Very High Frequency Resonant DC/DC Converters for LED Lighting

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Knott, Arnold; Andersen, Michael A. E.

    2013-01-01

    This paper presents a very high frequency DC/DC converter for LED lighting. Several resonant topologies are compared and their usability discussed. At the end the resonant SEPIC converter is chosen based on the achievable power density and total bill of material. Simulations of a 51 MHz converter...

  1. The role of high-frequency audiometry in early detection of ototoxicity

    NARCIS (Netherlands)

    Dreschler, W. A.; vd Hulst, R. J.; Tange, R. A.; Urbanus, N. A.

    1985-01-01

    Ototoxicity is one of the unwanted side-effects of a number of medical drugs. As ototoxicity appears to be most pronounced in the higher frequencies, it can be assessed at an earlier stage by using high-frequency audiometry from 8 to 20 kHz. We have investigated the precision of these measurements.

  2. Role of high-frequency audiometry in the early detection of ototoxicity. II. Clinical Aspects

    NARCIS (Netherlands)

    Dreschler, W. A.; van der Hulst, R. J.; Tange, R. A.; Urbanus, N. A.

    1989-01-01

    As a supplement to a previous paper [Dreschler et al.: Audiology 1985; 24:387-395] high-frequency (HF) audiometry was applied to compare the ototoxic effects of two different drug administration protocols for cis-platinum (CDDP). In both subgroups, HF audiometry considerably enhanced the early

  3. High frequency audiometry in prospective clinical research of ototoxicity due to platinum derivatives

    NARCIS (Netherlands)

    van der Hulst, R. J.; Dreschler, W. A.; Urbanus, N. A.

    1988-01-01

    The results of clinical use of routine high frequency audiometry in monitoring the ototoxic side effects of platinum and its derivatives are described in this prospective study. After demonstrating the reproducibility of the technique, we discuss the first results of an analysis of ototoxic side

  4. Pre- and postoperative high-frequency audiometry in otosclerosis. A study of 53 cases

    NARCIS (Netherlands)

    Tange, R. A.; Dreschler, W. A.

    1990-01-01

    A study was carried out to evaluate the results of stapes surgery in 53 cases of otosclerosis. The hearing function was measured pre- and postoperatively by means of conventional and high-frequency audiometry (Demlar 20K). The operative findings of the gradation of otosclerosis were compared with

  5. [Reparative Osteogenesis and Angiogenesis in Low Intensity Electromagnetic Radiation of Ultra-High Frequency].

    Science.gov (United States)

    Iryanov, Y M; Kiryanov, N A

    2015-01-01

    Non-drug correction of reparative bone tissue regeneration in different pathological states - one of the most actual problems of modern medicine. Our aim was to conduct morphological analysis of the influence of electromagnetic radiation of ultra-high frequency and low intensity on reparative osteogenesis and angiogenesis in fracture treatment under transosseous osteosynthesis. A controlled nonrandomized study was carried out. In the experiment conducted on rats we modeled tibial fracture with reposition and fixation of the bone fragments both in control and experimental groups. In the animals of the experimental group the fracture zone was exposed to low intensity electromagnetic radiation of ultra-high frequency. Exposure simulation was performed in the control group. The operated bones were examined using radiography, light and electronic microscopy, X-ray electronic probe microanalysis. It has been established that electromagnetic radiation of ultra-high frequency sessions in fracture treatment stimulate secretory activity and degranulation of mast cells, produce microcirculatory bed vascular permeability increase, endotheliocyte migration phenotype expression, provide endovascular endothelial outgrowth formation, activate reparative osteogenesis and angiogenesis while fracture reparation becomes the one of the primary type. The full periosteal, intermediary and intraosteal bone union was defined in 28 days. Among the therapeutic benefits of electromagnetic radiation of ultra-high frequency in fracture treatment we can detect mast cell secretorv activity stimulation and endovascular anziozenesis activation.

  6. Comovements of Returns and Volatility in International Stock Markets: A High-Frequency Approach

    NARCIS (Netherlands)

    Piplack, J.; Beine, M.; Candelon, B.

    2009-01-01

    This paper analyzes common factors in the continuous volatility component, co-extreme and co-jump behavior of a sample of stock market indices. In order to identify those components in stock price processes during a trading day we use high-frequency data and techniques. We show that in most of the

  7. High-frequency precursors to P-wave arrivals in New Zealand : implications for slab structure

    NARCIS (Netherlands)

    Hilst, R.D. van der; Snieder, R.K.

    1996-01-01

    This report revisits the very early high-frequency slab phases from earthquakes in the Kermadec slab (between −25°S and −37°S) that arrive as a precursor to the P wave onset at stations in New Zealand. The analysis of short-period digital records for station SNZO (South Karori New Zealand) for the

  8. Effect of high-frequency excitation on natural frequencies of spinning discs

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig

    2000-01-01

    The effect of high-frequency, non-resonant parametric excitation on the low-frequency response of spinning discs is considered. The parametric excitation is obtained through a non-constant rotation speed, where the frequency of the pulsating overlay is much higher than the lowest natural frequenc...

  9. Finite-Element Modeling of Viscoelastic Cells During High-Frequency Cyclic Strain

    Directory of Open Access Journals (Sweden)

    David W. Holdsworth

    2012-03-01

    Full Text Available Mechanotransduction refers to the mechanisms by which cells sense and respond to local loads and forces. The process of mechanotransduction plays an important role both in maintaining tissue viability and in remodeling to repair damage; moreover, it may be involved in the initiation and progression of diseases such as osteoarthritis and osteoporosis. An understanding of the mechanisms by which cells respond to surrounding tissue matrices or artificial biomaterials is crucial in regenerative medicine and in influencing cellular differentiation. Recent studies have shown that some cells may be most sensitive to low-amplitude, high-frequency (i.e., 1–100 Hz mechanical stimulation. Advances in finite-element modeling have made it possible to simulate high-frequency mechanical loading of cells. We have developed a viscoelastic finite-element model of an osteoblastic cell (including cytoskeletal actin stress fibers, attached to an elastomeric membrane undergoing cyclic isotropic radial strain with a peak value of 1,000 µstrain. The results indicate that cells experience significant stress and strain amplification when undergoing high-frequency strain, with peak values of cytoplasmic strain five times higher at 45 Hz than at 1 Hz, and peak Von Mises stress in the nucleus increased by a factor of two. Focal stress and strain amplification in cells undergoing high-frequency mechanical stimulation may play an important role in mechanotransduction.

  10. High-frequency asymptotics of solutions of ODE in a Banach space

    Science.gov (United States)

    Sazonov, L. I.

    2017-12-01

    We construct and justify high-frequency asymptotic expansions of solutions for some class of linear ODE in a Banach space. In particular, we obtain new results in the case when the averaged ODE are degenerate. The author is deceased. The editors are grateful to A. B. Morgulis, who finished the paper after the author’s death.

  11. Bilateral high frequency subthalamic stimulation in Parkinson's disease: long-term neurological follow-up

    NARCIS (Netherlands)

    Romito, L. M.; Scerrati, M.; Contarino, M. F.; Iacoangeli, M.; Bentivoglio, A. R.; Albanese, A.

    2003-01-01

    AIM: High frequency stimulation of the subthalamic nucleus (STN) is gaining recognition as a new symptomatic treatment for Parkinson's disease (PD). The first available long-term observations show the stability of the efficacy of this procedure in time. METHODS: Quadripolar leads were implanted

  12. Investigation into high-frequency-vibration assisted micro-blanking of pure copper foils

    Directory of Open Access Journals (Sweden)

    Wang Chunju

    2015-01-01

    Full Text Available The difficulties encountered during the manufacture of microparts are often associated with size effects relating to material, process and tooling. Utilizing acoustoplastic softening, achieved through a high-frequency vibration assisted micro-blanking process, was introduced to improve the surface finish in micro-blanking. A frequency of 1.0 kHz was chosen to activate the longitudinal vibration mode of the horn tip, using a piezoelectric actuator. A square hole with dimensions of 0.5 mm × 0.5 mm was made, successfully, from a commercial rolled T2 copper foil with 100 μm in thickness. It was found that the maximum blanking force could be reduced by 5% through utilizing the high-frequency vibration. Proportion of the smooth, burnished area in the cut cross-section increases with an increase of the plasticity to fracture, under the high-frequency vibration, which suggests that the vibration introduced is helpful for inhibiting evolution of the crack due to its acoustoplastic softening effect. During blanking, roughness of the burnished surface could be reduced by increasing the vibration amplitude of the punch, which played a role as surface polishing. The results obtained suggest that the high-frequency vibration can be adopted in micro-blanking in order to improve quality of the microparts.

  13. Surfactant nebulization versus instillation during high frequency ventilation in surfactant-deficient rabbits

    NARCIS (Netherlands)

    Dijk, Peter H.; Heikamp, A; Bambang Oetomo, Sidarto

    1998-01-01

    Surfactant nebulization improves lung function at low alveolar doses of surfactant. However, efficiency of nebulization is low, and lung deposition seems to depend on lung aeration. High frequency ventilation (HFV) has been shown to improve lung aeration. We hypothesize that the combination of HFV

  14. Discovery of high-frequency iron K lags in Ark 564 and Mrk 335

    NARCIS (Netherlands)

    Kara, E.; Fabian, A.C.; Cackett, E.M.; Uttley, P.; Wilkins, D.R.; Zoghbi, A.

    2013-01-01

    We use archival XMM-Newton observations of Ark 564 and Mrk 335 to calculate the frequency-dependent time lags for these two well-studied sources. We discover high-frequency Fe K lags in both sources, indicating that the red wing of the line precedes the rest-frame energy by roughly 100 and 150 s for

  15. Accelerated high-frequency repetitive transcranial magnetic stimulation enhances motor activity in rats

    NARCIS (Netherlands)

    El Arfani, Anissa; Parthoens, Joke; Demuyser, Thomas; Servaes, Stijn; De Coninck, Mattias; De Deyn, Peter Paul; Van Dam, Debby; Wyckhuys, Tine; Baeken, Chris; Smolders, Ilse; Staelens, Steven

    2017-01-01

    High-frequency repetitive transcranial magnetic stimulation (HF-rTMS) is currently accepted as an evidence-based treatment option for treatment-resistant depression (TRD). Additionally, HF-rTMS showed beneficial effects on psychomotor retardation in patients. The classical HF-rTMS paradigms however

  16. A Simplified Analytical Technique for High Frequency Characterization of Resonant Tunneling Diode

    Directory of Open Access Journals (Sweden)

    DESSOUKI, A. A. S.

    2014-11-01

    Full Text Available his paper proposes a simplified analytical technique for high frequency characterization of the resonant tunneling diode (RTD. An equivalent circuit of the RTD that consists of a parallel combination of conductance, G (V, f, and capacitance, C (V, f is formulated. The proposed approach uses the measured DC current versus voltage characteristic of the RTD to extract the equivalent circuit elements parameters in the entire bias range. Using the proposed analytical technique, the frequency response - including the high frequency range - of many characteristic aspects of the RTD is investigated. Also, the maximum oscillation frequency of the RTD is calculated. The results obtained have been compared with those concluded and reported in the literature. The reported results in literature were obtained through simulation of the RTD at high frequency using either a computationally complicated quantum simulator or through difficult RF measurements. A similar pattern of results and highly concordant conclusion are obtained. The proposed analytical technique is simple, correct, and appropriate to investigate the behavior of the RTD at high frequency. In addition, the proposed technique can be easily incorporated into SPICE program to simulate circuits containing RTD.

  17. Cluster observations of high-frequency waves in the exterior cusp

    Directory of Open Access Journals (Sweden)

    Y. Khotyaintsev

    2004-07-01

    Full Text Available We study wave emissions, in the frequency range from above the lower hybrid frequency up to the plasma frequency, observed during one of the Cluster crossings of a high-beta exterior cusp region on 4 March 2003. Waves are localized near narrow current sheets with a thickness a few times the ion inertial length; currents are strong, of the order of 0.1-0.5μA/m2 (0.1-0.5mA/m2 when mapped to ionosphere. The high frequency part of the waves, frequencies above the electron-cyclotron frequency, is analyzed in more detail. These high frequency waves can be broad-band, can have spectral peaks at the plasma frequency or spectral peaks at frequencies below the plasma frequency. The strongest wave emissions usually have a spectral peak near the plasma frequency. The wave emission intensity and spectral character change on a very short time scale, of the order of 1s. The wave emissions with strong spectral peaks near the plasma frequency are usually seen on the edges of the narrow current sheets. The most probable generation mechanism of high frequency waves are electron beams via bump-on-tail or electron two-stream instability. Buneman and ion-acoustic instability can be excluded as a possible generation mechanism of waves. We suggest that high frequency waves are generated by electron beams propagating along the separatrices of the reconnection region.

  18. Floquet engineering of long-range p -wave superconductivity: Beyond the high-frequency limit

    Science.gov (United States)

    Li, Zeng-Zhao; Lam, Chi-Hang; You, J. Q.

    2017-10-01

    It has been shown that long-range p -wave superconductivity in a Kitaev chain can be engineered via an ac field with a high frequency [M. Benito et al., Phys. Rev. B 90, 205127 (2014), 10.1103/PhysRevB.90.205127]. For its experimental realization, however, theoretical understanding of Floquet engineering with a broader range of driving frequencies becomes important. In this paper, focusing on the ac-driven tunneling interactions of a Kitaev chain, we investigate effects from the leading correction to the high-frequency limit on the emergent p -wave superconductivity. Importantly, we find new engineered long-range p -wave pairing interactions that can significantly alter the ones in the high-frequency limit at long interaction ranges. We also find that the leading correction additionally generates nearest-neighbor p -wave pairing interactions with a renormalized pairing energy, long-range tunneling interactions, and, in particular, multiple pairs of Floquet Majorana edge states that are destroyed in the high-frequency limit.

  19. Neural correlates of heterotopic facilitation induced after high frequency electrical stimulation of nociceptive pathways

    NARCIS (Netherlands)

    Broeke, E.N. van den; Heck, C.H. van; Rijn, C.M. van; Wilder-Smith, O.H.G.

    2011-01-01

    Background High frequency electrical stimulation (HFS) of primary nociceptive afferents in humans induce a heightened sensitivity in the surrounding non-stimulated skin area. Several studies suggest that this heterotopic effect is the result of central (spinal) plasticity. The aim of this study is

  20. Neural correlates of heterotopic facilitation induced after high frequency electrical stimulation of nociceptive pathways

    NARCIS (Netherlands)

    Broeke, E.N. van den; Heck, C.H. van; Rijn, C.M. van; Wilder-Smith, O.H.G.

    2011-01-01

    BACKGROUND: High frequency electrical stimulation (HFS) of primary nociceptive afferents in humans induce a heightened sensitivity in the surrounding non-stimulated skin area. Several studies suggest that this heterotopic effect is the result of central (spinal) plasticity. The aim of this study is

  1. A DC excited waveguide multibeam CO2 laser using high frequency ...

    Indian Academy of Sciences (India)

    A DC excited waveguide multibeam CO2 laser is reported having six glass discharge tubes. Simultaneous excitation of DC discharge in all sections is achieved by producing pre-ionization using an auxiliary high frequency pulsed discharge along with its other advantages. Maximum 170 W output power is obtained with all ...

  2. Suppression of high-frequency perturbations in pulse-width modulation

    DEFF Research Database (Denmark)

    2008-01-01

    A method suppresses high-frequency perturbations in a pulse-width modulated signal. The pulse-width modulation may superpose a carrier signal onto an input signal having a predetermined modulation frequency. The carrier signals may be phase-shifted. The resulting modulated signals may...

  3. Suppression of high-frequency perturbations in pulse-width modulation

    OpenAIRE

    Knott, Arnold

    2008-01-01

    A method suppresses high-frequency perturbations in a pulse-width modulated signal. The pulse-width modulation may superpose a carrier signal onto an input signal having a predetermined modulation frequency. The carrier signals may be phase-shifted. The resulting modulated signals may then be filtered and combined.

  4. High-frequency ultrasound for monitoring changes in liver tissue during preservation

    Science.gov (United States)

    Vlad, Roxana M.; Czarnota, Gregory J.; Giles, Anoja; Sherar, Michael D.; Hunt, John W.; Kolios, Michael C.

    2005-01-01

    Currently the only method to assess liver preservation injury is based on liver appearance and donor medical history. Previous work has shown that high-frequency ultrasound could detect ischemic cell death due to changes in cell morphology. In this study, we use high-frequency ultrasound integrated backscatter to assess liver damage in experimental models of liver ischemia. Ultimately, our goal is to predict organ suitability for transplantation using high-frequency imaging and spectral analysis techniques. To examine the effects of liver ischemia at different temperatures, livers from Wistar rats were surgically excised, immersed in phosphate buffer saline and stored at 4 and 20 °C for 24 h. To mimic organ preservation, livers were excised, flushed with University of Wisconsin (UW) solution and stored at 4 °C for 24 h. Preservation injury was simulated by either not flushing livers with UW solution or, before scanning, allowing livers to reach room temperature. Ultrasound images and corresponding radiofrequency data were collected over the ischemic period. No significant increase in integrated backscatter (~2.5 dBr) was measured for the livers prepared using standard preservation conditions. For all other ischemia models, the integrated backscatter increased by 4-9 dBr demonstrating kinetics dependent on storage conditions. The results provide a possible framework for using high-frequency imaging to non-invasively assess liver preservation injury.

  5. High-frequency ultrasound for monitoring changes in liver tissue during preservation

    Energy Technology Data Exchange (ETDEWEB)

    Vlad, Roxana M [Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada); Czarnota, Gregory J [Department of Radiation Oncology, University of Toronto, Toronto, Ontario (Canada); Giles, Anoja [Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada); Sherar, Michael D [Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada); Hunt, John W [Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada); Kolios, Michael C [Department of Medical Biophysics, University of Toronto, Toronto, Ontario (Canada)

    2005-01-21

    Currently the only method to assess liver preservation injury is based on liver appearance and donor medical history. Previous work has shown that high-frequency ultrasound could detect ischemic cell death due to changes in cell morphology. In this study, we use high-frequency ultrasound integrated backscatter to assess liver damage in experimental models of liver ischemia. Ultimately, our goal is to predict organ suitability for transplantation using high-frequency imaging and spectral analysis techniques. To examine the effects of liver ischemia at different temperatures, livers from Wistar rats were surgically excised, immersed in phosphate buffer saline and stored at 4 and 20 deg. C for 24 h. To mimic organ preservation, livers were excised, flushed with University of Wisconsin (UW) solution and stored at 4 deg. C for 24 h. Preservation injury was simulated by either not flushing livers with UW solution or, before scanning, allowing livers to reach room temperature. Ultrasound images and corresponding radiofrequency data were collected over the ischemic period. No significant increase in integrated backscatter ({approx}2.5 dBr) was measured for the livers prepared using standard preservation conditions. For all other ischemia models, the integrated backscatter increased by 4-9 dBr demonstrating kinetics dependent on storage conditions. The results provide a possible framework for using high-frequency imaging to non-invasively assess liver preservation injury.

  6. High-frequency EPR on high-spin transition-metal sites

    NARCIS (Netherlands)

    Mathies, Guinevere

    2012-01-01

    The electronic structure of transition-metal sites can be probed by electron-paramagnetic-resonance (EPR) spectroscopy. The study of high-spin transition-metal sites benefits from EPR spectroscopy at frequencies higher than the standard 9.5 GHz. However, high-frequency EPR is a developing field. In

  7. Effect of ischemia and cooling on the response to high frequency stimulation in rat tail nerves

    DEFF Research Database (Denmark)

    Andersen, Henning; Feldbæk Nielsen, Jørgen; Sørensen, Bodil

    2000-01-01

    In normal rat tail nerves the effect of temperature and ischemia on the response to long-term high frequency stimulation (HFS) (143 Hz) was studied. The effect of temperature was studied in two consecutive tests at 14 degrees C and 35 degrees C. Prior to the HFS the peak-to-peak amplitude (PP-amp...

  8. High-frequency oscillatory ventilation and pediatric cardiac surgery : Yes, we can!

    NARCIS (Netherlands)

    Kneyber, Martin C. J.

    2011-01-01

    In the previous issue of Critical Care, Bojan and colleagues reported their experiences with high-frequency oscillatory ventilation (HFOV) after pediatric cardiac surgery. A total of 120 patients were treated with HFOV on the day of surgery, thus excluding rescue HFOV use. The main finding of the

  9. Periodic Driving at High Frequencies of an Impurity in the Isotropic XY Chain

    Science.gov (United States)

    Corsi, Livia; Genovese, Giuseppe

    2017-09-01

    We study the isotropic XY chain with a transverse magnetic field acting on a single site and analyse the long time behaviour of the time-dependent state of the system when a periodic perturbation drives the impurity. We find that for high frequencies the state approaches a periodic orbit synchronised with the forcing and provide the explicit rate of convergence to the asymptotics.

  10. Reflections on Pediatric High-Frequency Oscillatory Ventilation From a Physiologic Perspective

    NARCIS (Netherlands)

    Kneyber, Martin C. J.; van Heerde, Marc; Markhorst, Dick G.

    Mechanical ventilation using low tidal volumes has become universally accepted to prevent ventilator-induced lung injury. High-frequency oscillatory ventilation (HFOV) allows pulmonary gas exchange using very small tidal volume (1-2 mL/kg) with concomitant decreased risk of atelectrauma. However,

  11. Acceleration of fibrinolysis by high-frequency ultrasound: The contribution of acoustic streaming and temperature rise

    NARCIS (Netherlands)

    Sakharov, D.V.; Hekkenberg, R.T.; Rijken, D.C.

    2000-01-01

    High-frequency ultrasound has been shown to accelerate enzymatic fibrinolysis. One of the supposed mechanisms of this effect is the enhancement of mass transport by acoustic streaming, i.e., ultrasound-induced macroscopic flow around the clot. In this study, which is aimed at further elucidating the

  12. Ventilation strategies and outcome in randomised trials of high frequency ventilation

    OpenAIRE

    Thome, U; Carlo, W; Pohlandt, F

    2005-01-01

    Objective: Randomised controlled trials comparing elective use of high frequency ventilation (HFV) with conventional mechanical ventilation (CMV) in preterm infants have yielded conflicting results. We hypothesised that the variability of results may be explained by differences in study design, ventilation strategies, delay in initiation of HFV, and use of permissive hypercapnia.

  13. Sensors for High Frequency monitoring of cyanoHABs and cyanotoxin production

    Science.gov (United States)

    The use of sensors in environmental monitoring is an area of constant evolution. As monitoring needs present themselves, technology development follows. Here, the use of high frequency data to monitor and predict HABs is presented illustrating the successful use of technology a...

  14. Characterization of genomic deletion efficiency mediated by clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 nuclease system in mammalian cells.

    Science.gov (United States)

    Canver, Matthew C; Bauer, Daniel E; Dass, Abhishek; Yien, Yvette Y; Chung, Jacky; Masuda, Takeshi; Maeda, Takahiro; Paw, Barry H; Orkin, Stuart H

    2014-08-01

    The clustered regularly interspaced short [corrected] palindromic repeats (CRISPR)/CRISPR-associated (Cas) 9 nuclease system has provided a powerful tool for genome engineering. Double strand breaks may trigger nonhomologous end joining repair, leading to frameshift mutations, or homology-directed repair using an extrachromosomal template. Alternatively, genomic deletions may be produced by a pair of double strand breaks. The efficiency of CRISPR/Cas9-mediated genomic deletions has not been systematically explored. Here, we present a methodology for the production of deletions in mammalian cells, ranging from 1.3 kb to greater than 1 Mb. We observed a high frequency of intended genomic deletions. Nondeleted alleles are nonetheless often edited with inversions or small insertion/deletions produced at CRISPR recognition sites. Deleted alleles also typically include small insertion/deletions at predicted deletion junctions. We retrieved cells with biallelic deletion at a frequency exceeding that of probabilistic expectation. We demonstrate an inverse relationship between deletion frequency and deletion size. This work suggests that CRISPR/Cas9 is a robust system to produce a spectrum of genomic deletions to allow investigation of genes and genetic elements. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  15. On the Importance of High Frequency Gravity Waves for Ice Nucleation in the Tropical Tropopause Layer

    Science.gov (United States)

    Jensen, Eric J.

    2016-01-01

    Recent investigations of the influence of atmospheric waves on ice nucleation in cirrus have identified a number of key processes and sensitivities: (1) ice concentrations produced by homogeneous freezing are strongly dependent on cooling rates, with gravity waves dominating upper tropospheric cooling rates; (2) rapid cooling driven by high-frequency waves are likely responsible for the rare occurrences of very high ice concentrations in cirrus; (3) sedimentation and entrainment tend to decrease ice concentrations as cirrus age; and (4) in some situations, changes in temperature tendency driven by high-frequency waves can quench ice nucleation events and limit ice concentrations. Here we use parcel-model simulations of ice nucleation driven by long-duration, constant-pressure balloon temperature time series, along with an extensive dataset of cold cirrus microphysical properties from the recent ATTREX high-altitude aircraft campaign, to statistically examine the importance of high-frequency waves as well as the consistency between our theoretical understanding of ice nucleation and observed ice concentrations. The parcel-model simulations indicate common occurrence of peak ice concentrations exceeding several hundred per liter. Sedimentation and entrainment would reduce ice concentrations as clouds age, but 1-D simulations using a wave parameterization (which underestimates rapid cooling events) still produce ice concentrations higher than indicated by observations. We find that quenching of nucleation events by high-frequency waves occurs infrequently and does not prevent occurrences of large ice concentrations in parcel simulations of homogeneous freezing. In fact, the high-frequency variability in the balloon temperature data is entirely responsible for production of these high ice concentrations in the simulations.

  16. Application of high frequency ultrasound in the destruction of DDT in contaminated sand and water.

    Science.gov (United States)

    Thangavadivel, Kandasamy; Megharaj, Mallavarapu; Smart, Roger St C; Lesniewski, Peter J; Naidu, Ravi

    2009-09-15

    High frequency ultrasound, as an alternative to high cost incineration, has been investigated to remediate DDT from sand and soil slurries. In this study, low power high frequency ultrasound (1.6 MHz; 150 W/L), with operating costs much lower than low frequency ultrasound, has been used to remediate DDT in liquid solution and in sand slurries. At 1.6 MHz, the wavelength, cycle time, bubble size and bubble life time are much smaller and the number of bubbles per litre is much larger than at frequencies below 50 kHz. These large differences affect the effective mass transfer to the bubbles and subsequent energy release, hydrolysis of water and degradation mechanism. Based on DDT measurement, using high frequency ultrasound, 90% of 8 mg/L of DDT from liquid solution was destroyed in 90 min. Removal efficiency from 32.6 mg/L of DDT in a 40 wt.% sand slurry was 22% in 90 min. Other slurry and DDT combinations are reported. Incremental chloride measurements indicated that combination of ultrasound and iron powder helps to increase the remediation rate of DDT from sand slurry, e.g. 46% cf. 32% for a 20 wt.% slurry. The results show that high frequency ultrasound is effective in degrading the non-polar pollutant DDT dispersed in water and in sand slurry. In practice, due to intensity limitations in currently available equipment and higher attenuation of energy, high frequency ultrasound has a low volume coverage and would require circulation of the slurry past the sonotrode, multiple sonotrodes, larger sonotrode area and lower slurry densities may still be required.

  17. DNA restriction fragment length polymorphisms in differential diagnosis of genetic disease: application in neuromuscular diseases

    NARCIS (Netherlands)

    Defesche, J. C.; de Vissar, M.; Bakker, E.; Bouwsma, G.; de Vijlder, J. J.; Bolhuis, P. A.

    1989-01-01

    Three families, in which several male individuals suffer from a hereditary neuromuscular disease, were examined by analysis of naturally occurring restriction fragment length polymorphisms (RFLPs) and by screening for deletions. Originally, differential diagnosis included spinal muscular atrophy

  18. ACE I/D polymorphism in Indian patients with hypertrophic cardiomyopathy and dilated cardiomyopathy

    DEFF Research Database (Denmark)

    Rai, Taranjit Singh; Dhandapany, Perundurai Subramaniam; Ahluwalia, Tarun Veer Singh

    2008-01-01

    The study was carried to determine the association of angiotensin converting enzyme (ACE) insertion/deletion (I/D) polymorphism with the risk of hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and restrictive cardiomyopathy (RCM).......The study was carried to determine the association of angiotensin converting enzyme (ACE) insertion/deletion (I/D) polymorphism with the risk of hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and restrictive cardiomyopathy (RCM)....

  19. Molecular analysis of the Duchenne muscular dystrophy gene in Spanish individuals: Deletion detection and familial diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Patino, A.; Garcia-Delgado, M.; Narbona, J. [Univ. of Navarra, Pamplona (Spain)

    1995-11-06

    Deletion studies were performed in 26 Duchenne muscular dystrophy (DMD) patients through amplification of nine different exons by multiplex polymerase chain reaction (PCR). DNA from paraffin-embedded muscle biopsies was analyzed in 12 of the 26 patients studied. Optimization of this technique is of great utility because it enables analysis of material stored in pathology archives. PCR deletion detection, useful in DMD-affected boys, is problematic in determining the carrier state in female relatives. For this reason, to perform familial linkage diagnosis, we made use of a dinucleotide repeat polymorphism (STRP, or short tandem repeat polymorphism) located in intron 49 of the gene. We designed a new pair of primers that enabled the detection of 22 different alleles in relatives in the 14 DMD families studied. The use of this marker allowed familial diagnosis in 11 of the 14 DMD families and detection of de novo deletions in 3 of the probands. 8 refs., 5 figs., 2 tabs.

  20. Development of high frequency focused transducers for single beam acoustic tweezers

    Science.gov (United States)

    Hsu, Hsiu-Sheng

    Contactless particle trapping and manipulation have found many potential applications in diverse fields, especially in biological and medical research. Among the various methods, optical tweezers is the most well-known and extensively investigated technique. However, there are some limitations for particle manipulation based on optical tweezers. Due to the conceptual similarity with the optical tweezers and recent advances in high frequency ultrasonic transducer, a single beam acoustic tweezer using high frequency (≥ 20 MHz) focused transducer has recently been considered, and its feasibility was theoretically and experimentally investigated. This dissertation mainly describes the development of high frequency focused ultrasonic transducers for single beam acoustic tweezers applications. Three different types of transducers were fabricated. First, a 60 MHz miniature focused transducer (rabbit eye was also obtained with this device. Second approach is to build a 200 MHz self-focused ZnO transducer by sputtering ZnO film on a curved surface of the aluminum backing material. An individual 10 microm microsphere was effectively manipulated in two dimensions by this type of transducer. Another ultrahigh frequency focused transducer based on silicon lens design has also been developed, where a 330 MHz silicon lens transducer was fabricated and evaluated. Microparticle trapping experiment was carried out to demonstrate that silicon lens transducer can manipulate a single microsphere as small as 5 microm. The realization of single beam acoustic tweezers using high frequency focused transducers can offer wide range of applications in biomedical and chemical sciences including intercellular kinetics studies and cell stimulation. Additionally, we propose a simple and efficient approach to prepare xPMN-PT-(1-x)PZT (where x is 0.1, 0.3, 0.5, 0.7 and 0.9) composite films with controllable dielectric constant that offers better performance for high frequency ultrasonic

  1. Gas exchange and lung mechanics during high frequency ventilation in the perflubron-treated lung.

    Science.gov (United States)

    Wolf, Gerhard K; Sheeran, Padraig; Heitz, David; Thompson, John E; Arnold, John H

    2008-11-01

    To identify the effect of perflubron on gas exchange and lung mechanics during high frequency oscillatory ventilation in an animal model. Prospective randomized animal trial. Eighteen Yorkshire swine. Three groups of six animals each were investigated: control (high frequency oscillatory ventilation alone), low dose perflubron (high frequency oscillatory ventilation plus perfluoro-octyl bromide [PFOB]-Lo, 1.5 mL/kg), and high dose perflubron (high frequency oscillatory ventilation plus PFOB-Hi, 3 mL/kg). Lung injury was induced with repeated saline lavage and amplified for 1 hr using large tidal volumes. Perflubron (Alliance, CA) or a sham dose (room air) was administered with bronchoscopic guidance. The animals were transitioned to high frequency oscillatory ventilation starting at a mean airway pressure of 15 cm H2O. Mean airway pressure was increased (inflation phase) by 5 cm H2O every 15 mins to a maximum mean airway pressure of 40 cm H2O. During the deflation phase, mean airway pressure was reduced by 5 cm H2O every 15 mins to a mean airway pressure of 15 cm H2O. Oxygenation was improved and pulmonary shunt fraction was reduced for PFOB-Hi compared with the control group only at a mean airway pressure of 15 and 20 cm H2O. At a maximal mean airway pressure of 40 cm H2O, oxygenation was not different between the groups, but pulmonary artery pressures were elevated in both PFOB-groups compared with the control group. During the deflation phase, oxygenation, pulmonary shunt fraction, and pulmonary artery pressures were adversely affected by PFOB-Hi and PFOB-Lo. Although PFOB-Hi compared with the control group improved oxygenation and reduced pulmonary shunt fraction only during the first pressure steps of a formal stepwise recruitment maneuver during high frequency oscillatory ventilation, this effect was not sustained during maximal recruitment. During the deflation phase, both PFOB groups were associated with worse gas exchange compared with the control group

  2. Investigation of polyvinylidene fluoride (PVDF) films in identifying high-frequency vibration modes of flexible plates.

    Science.gov (United States)

    Chuang, Kuo-Chih; Liou, Hong-Cin; Ma, Chien-Ching

    2014-06-01

    Compared with piezoelectric ceramics such as lead zirconate titanate (PZT) ceramics, the low density and high compliance of the PVDF films make them a more suitable choice in modal testing, especially for detecting high-frequency modes in flexible or inflatable structures. In this work, dynamic sensing performances of PVDF films for flexible structures in modal testing are examined, with considerations including the repeatability of the impact source, the accuracy of the sensing responses, and the influences of the nodal lines on the frequency spectra of the transient responses. Two flexible plates with different boundary conditions and thickness are considered. Experimental results, compared with FEM computations or theoretical predictions, demonstrate the excellent dynamic sensing performance of the PVDF film in modal testing applications, especially for identification of high-frequency modes on flexible structures.

  3. The Effect of High-Frequency Parametric Excitation on a Stochastically Driven Pantograph-Catenary System

    Directory of Open Access Journals (Sweden)

    R. H. Huan

    2014-01-01

    Full Text Available In high-speed electric trains, a pantograph is mounted on the roof of the train to collect power through contact with an overhead catenary wire. The effect of fast harmonic and parametric excitation on a stochastically driven pantograph-catenary system is studied in this paper. A single-degree-of-freedom model of the pantograph-catenary system is adopted, wherein the stiffness of the nonlinear spring has a time-varying component characterized by both low and high frequencies. Using perturbation and harmonic averaging, a Fokker-Planck-Kolmogorov equation governing the stationary response of the pantograph-catenary system is set up. Based on the transition probability density of the stationary response, it is found that even small high-frequency parametric excitation has an appreciable effect on the system response. Among other things, it shifts the resonant frequency and often changes the response characteristics markedly.

  4. Broadband measurements of high-frequency electric field levels and exposure ratios determination

    Directory of Open Access Journals (Sweden)

    Vulević Branislav

    2017-01-01

    Full Text Available The exposure of people to high-frequency electromagnetic fields (over 100 kHz that emanate from modern wireless information transmission systems is inevitable in modern times. Due to the rapid development of new technologies, measuring devices and their connection to measuring systems, the first fifteen years of the 21st century are characterized by the appearance of different approaches to measurements. This prompts the need for the assessment of the exposure of people to these fields. The main purpose of this paper is to show how to determine the exposure ratios based on the results of broadband measurements of the high-frequency electric field in the range of 3 MHz to 18 GHz in the environment.

  5. On the synthesis of multiple frequency tone burst stimuli for efficient high frequency auditory brainstem response.

    Science.gov (United States)

    Ellingson, Roger M; Dille, Marilyn L; Leek, Marjorie R; Fausti, Stephen A

    2008-01-01

    The development and digital waveform synthesis of a multiple-frequency tone-burst (MFTB) stimulus is presented. The stimulus is designed to improve the efficiency of monitoring high-frequency auditory-brainstem-response (ABR) hearing thresholds. The pure-tone-based, fractional-octave-bandwidth MFTB supports frequency selective ABR audiometry with a bandwidth that falls between the conventional click and single-frequency tone-burst stimuli. The MFTB is being used to identify high frequency hearing threshold change due to ototoxic medication which most generally starts at the ultra-highest hearing frequencies and progresses downwards but could be useful in general limited-bandwidth testing applications. Included is a Mathcad implementation and analysis of our MFTB synthesis technique and sample performance measurements of the MFTB stimulus configuration used in a clinical research ABR system.

  6. Multicompartment retinal ganglion cells response to high frequency bi-phasic pulse train stimulation: Simulation results.

    Science.gov (United States)

    Maturana, Matias I; Grayden, David B; Burkitt, Anthony N; Meffin, Hamish; Kameneva, Tatiana

    2013-01-01

    Retinal ganglion cells (RGCs) are the sole output neurons of the retina that carry information about a visual scene to the brain. By stimulating RGCs with electrical stimulation, it is possible to elicit a sensation of light for people with macular degeneration or retinitis pigmentosa. To investigate the responses of RGCs to high frequency bi-phasic pulse train stimulation, we use previously constrained models of multi-compartment OFF RGCs. The morphologies of mouse RGCs are taken from the Chalupa set of the NeuroMorpho database. The cell models are divided into compartments representing the dendrites, soma and axon that vary between the cells. A total of 132 cells are simulated in the NEURON environment. Results show that the cell morphology plays an important role in the response characteristics of the cell to high frequency bi-phasic pulse train stimulation.

  7. Price duration versus trading volume in high-frequency data for selected DAX companies

    Directory of Open Access Journals (Sweden)

    Christoph Mitterer

    2016-12-01

    Full Text Available The properties of the time series of durations between consecutive trades of a particular stock have been studied by many contributors in the literature of financial econometrics. Among them are highly prominent scientists like Engle (2000 and Gourieroux and Jasiak (2001. The importance of this topic, accompanied by the growing availability of (ultra-high-frequency data, has prompted an increase of contributions in recent years. Intensive research based on high-frequency data has several financial motivations. First of all, it is linked with microstructure theory. Secondly, it contributes to the literature on stochastic time deformation. But the most important need for research on the dynamics of trade durations is the necessity to manage liquidity risk. The reason is that durations between the following trades are a widely accepted measures of market liquidity. In addition, their volatility reflects the liquidity risk.

  8. Lateralization of high frequency sounds as a function of interaural amplitude disparity.

    Science.gov (United States)

    Rule, S J; Nickolaychuk, B R

    1995-09-01

    Twenty-five subjects made graphic ratings of the perceived lateral position within the head of sounds presented through headphones. The stimuli were high frequency, pure tones and amplitude modulated sounds. For the amplitude modulated sounds, a 200 HZ modulation frequency was combined with carrier frequencies of 2200 HZ, 3200 HZ, 4200 HZ, and 5200 HZ, which were also the pure tone frequencies. Interaural level differences in the signals ranged from zero to 12 dB. The rate of lateralization was defined as the slope of the linear trend relating laterality ratings to interaural level differences. The rate of lateralization was found to be a decreasing function of frequency. The laterality ratings of amplitude modulated signals were nearly identical to those for pure tones. This result suggests that, for high frequency signals, conflicting temporal information that a source is centered is suppressed in favor of information from level differences that the source is off-center.

  9. Capturing temporal variation in phosphorus dynamics in groundwater dominated rivers using automated high-frequency sampling

    Science.gov (United States)

    Bieroza, M. Z.; Heathwaite, A. L.; Mullinger, N. J.; Keenan, P. O.

    2012-04-01

    High-frequency river water quality monitoring provides detailed hydrochemical information on the time scale of hydrologic response. Several studies (Kirchner et al., 2004; Johnes, 2007; Cassidy and Jordan, 2011) have shown previously that coarse sampling approaches fail to quantify nutrient and sediment loads and to capture the fine structure of water quality dynamics correctly. A robust analysis of high-frequency nutrient and water quality time series can present a complex conceptual, analytical and computational problem. High-frequency nutrient monitoring provides new evidence of processes and patterns that could not be observed previously using standard coarse resolution sampling schemes. However, to fully utilise the wealth of information contained in high-frequency nutrient data, we need to address the following questions: how to detect complex coupling patterns and processes in high-resolution flow-nutrients data, how do these patterns and processes change throughout the period of observation, and how to distinguish noise signals from an evidence of real processes (Harris and Heathwaite, 2005). Here, hourly measurements of total phosphorus (TP), soluble reactive phosphorus (SRP) and turbidity were carried out using bank side analysers to study the biogeochemical response of a 54 km2 catchment of the River Leith, a tributary of the River Eden (Cumbria, UK). A remote automated mobile lab facilitates real-time high-frequency nutrient and water quality monitoring, with no time delay between collection and analysis of the reactive elements. The objectives of this study were two-fold: first to investigate the intrinsic complexity of the temporal relationship between phosphorus fractions (SRP, TP), turbidity and continuous hydrometric time series and secondly to investigate the possibilities of missing high-frequency phosphorus data infilling using continuous hydrometric time series. Complex non-linear relationships between flow, TP and SRP, turbidity were observed

  10. High shock, high frequency characteristics of a mechanical isolator for a piezoresistive accelerometer

    Energy Technology Data Exchange (ETDEWEB)

    Bateman, V.I.; Brown, F.A.; Davie, N.T. [and others

    1995-07-01

    A mechanical isolator has been developed for a piezoresistive accelerometer. The purpose of the isolator is to mitigate high frequency shocks before they reach the accelerometer because the high frequency shocks may cause the accelerometer to resonate. Since the accelerometer is undamped, it often breaks when it resonates. The mechanical isolator was developed in response to impact test requirements for a variety of structures at Sandia National Laboratories. An Extended Technical Assistance Program with the accelerometer manufacturer has resulted in a commercial isolator that will be available to the general public. This mechanical isolator has ten times the bandwidth of any other commercial isolator and has acceptable frequency domain performance from DC to 10 kHz ({plus_minus} 10%) over a temperature range of -65{degrees}F to +185{degrees}F as demonstrated in this paper.

  11. Energy conservation and high-frequency damping in numerical time integration

    DEFF Research Database (Denmark)

    Krenk, Steen

    2008-01-01

    additional variables to represent damping. In the present paper it is demonstrated, how damping equivalent to the α-damping of the Newmark algorithm can be introduced directly via displacement and velocity dependent terms. It is furthermore shown, how this damping can be improved by introduction of a new set...... this often leads to a fairly large number of high-frequency modes, that are not represented well – and occasionally directly erroneously – by the model. It is desirable to cure this problem by devising algorithms that include the possibility of introducing algorithmic energy dissipation of the high......-frequency modes. The problem is well known from classic collocation based algorithms – notably various forms of the Newmark algorithm – where the equation of motion is supplemented by approximate relations between displacement, velocity and acceleration. Here adjustment of the algorithmic parameters can be used...

  12. Energy conservation and high-frequency damping in numerical time-integration

    DEFF Research Database (Denmark)

    Krenk, Steen

    2007-01-01

    by introduction of a new set of variables related to the displacement and velocity vectors by a suitable first order filter with scalar coefficients. By this device an algorithmic damping can be obtained that is of third order in the low-frequency regime. It is an important feature of both algorithms...... this often leads to a fairly large number of high-frequency modes, that are not represented well - and occasionally directly erroneously - by the model. It is desirable to cure this problem by devising algorithms that include the possibility of introducing algorithmic energy dissipation of the high......-frequency modes. The problem is well known from classic collocation based algorithms - notably various forms of the Newmark algorithm where the equation of motion is supplemented by approximate relations between displacement, velocity and acceleration. Here adjustment of the algorithmic parameters can be used...

  13. Cisplatin-based chemotherapy: Add high-frequency audiometry in the regimen.

    Science.gov (United States)

    Arora, R; Thakur, J S; Azad, R K; Mohindroo, N K; Sharma, D R; Seam, R K

    2009-01-01

    Cisplatin-induced ototoxicity shows high interindividual variability and is often accompanied by transient or permanent tinnitus. It is not possible to identify the susceptible individuals before commencement of the treatment. We conducted a prospective, randomized and observational study in a tertiary care centre and evaluated the effects of different doses of cisplatin on hearing. Fifty-seven patients scheduled for cisplatin-based chemotherapy were included in the study. All patients were divided into three groups depending on the dose of cisplatin infused in 3 weeks. The subjective hearing loss was found in seven patients, while six patients had tinnitus during the chemotherapy. The hearing loss was sensorineural, dose dependent, symmetrical, bilateral and irreversible. Higher frequencies were first to be affected in cisplatin chemotherapy. As use of high-frequency audiometry is still limited in research work only, we need a strict protocol of adding high-frequency audiometry in the cisplatin-based chemotherapy regimen.

  14. On board electronic devices safety subject to high frequency electromagnetic radiation effects

    Science.gov (United States)

    Nikitin, V. F.; Smirnov, N. N.; Smirnova, M. N.; Tyurenkova, V. V.

    2017-06-01

    Spacecraft on board electronic devices are subjected to the effects of Space environment, in particular, electromagnetic radiation. The weight limitations for spacecraft pose an important material and structures problem: developing effective protection for on board electronic devices from high frequency electromagnetic radiation. In the present paper the problem of the effect of external high frequency electromagnetic field on electronic devices shielding located on orbital platforms is investigated theoretically. It is demonstrated that the characteristic time for the unsteady stage of the process is negligibly small as compared with characteristic time of electromagnetic field diffusion into a conductor for the studied range of governing parameters. A system of governing material parameters is distinguished, which contribute to protecting electronic devices from induced electrical currents.

  15. High-frequency programmable acoustic wave device realized through ferroelectric domain engineering

    Energy Technology Data Exchange (ETDEWEB)

    Ivry, Yachin, E-mail: ivry@mit.edu, E-mail: cd229@eng.cam.ac.uk; Wang, Nan; Durkan, Colm, E-mail: ivry@mit.edu, E-mail: cd229@eng.cam.ac.uk [Nanoscience Centre, University of Cambridge, 11 JJ Thomson Avenue, Cambridge CB3 0FF (United Kingdom)

    2014-03-31

    Surface acoustic wave devices are extensively used in contemporary wireless communication devices. We used atomic force microscopy to form periodic macroscopic ferroelectric domains in sol-gel deposited lead zirconate titanate, where each ferroelectric domain is composed of many crystallites, each of which contains many microscopic ferroelastic domains. We examined the electro-acoustic characteristics of the apparatus and found a resonator behavior similar to that of an equivalent surface or bulk acoustic wave device. We show that the operational frequency of the device can be tailored by altering the periodicity of the engineered domains and demonstrate high-frequency filter behavior (>8 GHz), allowing low-cost programmable high-frequency resonators.

  16. Circuit and Technology Considerations for High Frequency Switched-Capacitor Filters.

    Science.gov (United States)

    Kaneshiro, Ronald Takeshi

    Since its inception in the late 1970's, the switched -capacitor filtering technique has been very widely applied in the telecommunications field. If this technique can be extended into a much higher frequency range, its applicability can be broadened into areas that are currently dominated by non-monolithic design methods. Past attempts to design practical and reproducible high frequency and high selectivity filters have been hindered by the problems related to the filter architecture, high speed monolithic amplifier design, and integrated circuit technology. In this dissertation the problems of high speed amplifier design and integrated circuit technology in relation to the realization of. practical high frequency switched-capacitor filters are addressed and investigated. *This research was sponsored by National Science Foundation Grant NSF ENG-7907055 and DARPA Grant N00039 -81-K-0251.

  17. Theta and High-Frequency Activity Mark Spontaneous Recall of Episodic Memories

    Science.gov (United States)

    Burke, John F.; Sharan, Ashwini D.; Sperling, Michael R.; Ramayya, Ashwin G.; Evans, James J.; Healey, M. Karl; Beck, Erin N.; Davis, Kathryn A.; Lucas, Timothy H.

    2014-01-01

    Humans possess the remarkable ability to search their memory, allowing specific past episodes to be re-experienced spontaneously. Here, we administered a free recall test to 114 neurosurgical patients and used intracranial theta and high-frequency activity (HFA) to identify the spatiotemporal pattern of neural activity underlying spontaneous episodic retrieval. We found that retrieval evolved in three electrophysiological stages composed of: (1) early theta oscillations in the right temporal cortex, (2) increased HFA in the left hemisphere including the medial temporal lobe (MTL), left inferior frontal gyrus, as well as the ventrolateral temporal cortex, and (3) motor/language activation during vocalization of the retrieved item. Of these responses, increased HFA in the left MTL predicted recall performance. These results suggest that spontaneous recall of verbal episodic memories involves a spatiotemporal pattern of spectral changes across the brain; however, high-frequency activity in the left MTL represents a final common pathway of episodic retrieval. PMID:25143616

  18. High aspect ratio MEMS capacitor for high frequency impedance matching applications

    DEFF Research Database (Denmark)

    Yalcinkaya, Arda Deniz; Jensen, Søren; Hansen, Ole

    2003-01-01

    We present a microelectromechanical tunable capacitor with a low control voltage, a wide tuning range and adequate electrical quality factor. The device is fabricated in a single-crystalline silicon layer using deep reactive ion etching (DRIE) for obtaining high-aspect ratio (> 20) parallel comb......-drive structures with vertical sidewalls. The process sequence for fabrication of the devices uses only one lithographic masking step and can be completed in a short time. The fabricated device was characterized with respect to electrical quality factor, tuning range, self-resonance frequency and transient...... response and it was found that the device is a suitable passive component to be used in impedance matching applications, band-pass filtering or voltage controlled oscillators in the Very High Frequency (VHF) and Ultra High Frequency (UHF) bands....

  19. Determination of the High Frequency Inductance Profile of Surface Mounted Permanent Magnet Synchronous Motors

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Rasmussen, Peter Omand; Ritchie, Ewen

    2008-01-01

    Accurate knowledge of the high frequency inductance profile plays an important role in many designs of sensorless controllers for Surface inductance. A special algorithm is used to decouple the cross-coupling effects between the d-axis and the q-axis, which allows Mounted Permanent Magnet (SMPM......) synchronous motors. This paper presents an AC+DC measurement method for determination of the d-axis and q-axis high frequency inductance profiles of SMPM synchronous motors. This method uses DC currents to set a desired magnetic working point on the motor laminations, and then superimpose balanced small AC...... signals to measure the incremental a separate determination of the d, q inductance profiles as functions of the d, q currents. Experimental results on a commercial SMPM motor using the proposed method are presented in this paper....

  20. Calculation of high frequency ultrasonic signals for shear wave insonification in solid material.

    Science.gov (United States)

    Schmitz, V; Langenberg, K J; Chakhlov, S

    2004-04-01

    The goal of the theoretical part is to simulate an automatic ultrasonic inspection with contact technique shear wave probes, where the high frequency signals are captured and used to perform a reconstruction based on the synthetic aperture focusing method "SAFT". Therefore the ultrasonic probe, the scanning path and the defects are parameters in a CAD model. The scattering behavior of the defect is calculated by the Kirchhoff approximation in its elastodynamic version. The result of the simulation--the high frequency data--and the result of the SAFT-reconstructions are compared with experimental results on a steel test block with side drilled and flat bottom holes. The model is validated by the experiment. One of the applications of the model is to identify multiple reflections.

  1. Optimized shielded-gate trench MOSFET technology for high-frequency, high-efficiency power supplies

    Science.gov (United States)

    Challa, Ashok; Sarkar, Tirthajyoti; Sapp, Steven

    2012-10-01

    Shielded-gate trench-MOSFETs yield superior performance compared to conventional gate trench devices by allowing higher doping density in the drift region and providing a `shielding effect' for the gate by placing an intermediate electrode between gate and drain. However, further design optimizations can be done for a shieldedgate trench-MOSFET to improve performance parameters particularly suited for next-generation high-frequency computing power supply applications and they have been outlined in this article. Channel optimization, substrate thinning and intrinsic gate resistance reduction (by layout enhancements) have been discussed along with their impact on cost-performance benefit on the device. Further, effects of these design optimizations on the power loss and efficiency of a high-frequency switching converter have been demonstrated by mixed device-circuit simulations.

  2. On the use of high-frequency SCADA data for improved wind turbine performance monitoring

    Science.gov (United States)

    Gonzalez, E.; Stephen, B.; Infield, D.; Melero, J. J.

    2017-11-01

    SCADA-based condition monitoring of wind turbines facilitates the move from costly corrective repairs towards more proactive maintenance strategies. In this work, we advocate the use of high-frequency SCADA data and quantile regression to build a cost effective performance monitoring tool. The benefits of the approach are demonstrated through the comparison between state-of-the-art deterministic power curve modelling techniques and the suggested probabilistic model. Detection capabilities are compared for low and high-frequency SCADA data, providing evidence for monitoring at higher resolutions. Operational data from healthy and faulty turbines are used to provide a practical example of usage with the proposed tool, effectively achieving the detection of an incipient gearbox malfunction at a time horizon of more than one month prior to the actual occurrence of the failure.

  3. Stimulus induced high frequency oscillations are present in neuronal networks on microelectrode arrays.

    Directory of Open Access Journals (Sweden)

    Chadwick M Hales

    2012-05-01

    Full Text Available Pathological high frequency oscillations (250-600Hz are present in the brains of epileptic animals and humans. The etiology of these oscillations and how they contribute to the diseased state remains unclear. This work identifies the presence of microstimulation-evoked high frequency oscillations (250-400Hz in dissociated neuronal networks cultured on microelectrode arrays (MEAs. Oscillations are more apparent with higher stimulus voltages. As with in vivo studies, activity is isolated to a single electrode, however the MEA provides improved spatial resolution with no spread of the oscillation to adjacent electrodes 200µm away. Oscillations develop across 4 weeks in vitro. Oscillations still occur in the presence of tetrodotoxin and synaptic blockers, and they cause no apparent disruption in the ability of oscillation-presenting electrodes to elicit directly evoked action potentials (dAPs or promote the spread of synaptic activity throughout the culture. Chelating calcium with ethylene glycol tetraacetic acid (EGTA causes a temporal prolongation of the oscillation. Finally, carbenoxolone significantly reduces or eliminates the high frequency oscillations. Gap junctions may play a significant role in maintaining the oscillation given the inhibitory effect of carbenoxolone, the propagating effect of reduced calcium conditions and the isolated nature of the activity as demonstrated in previous studies. This is the first demonstration of stimulus evoked high frequency oscillations in dissociated cultures. Unlike current models that rely on complex in vivo recording conditions, this work presents a simple controllable model in neuronal cultures on MEAs to further investigate how the oscillations occur at the molecular level and how they may contribute to the pathophysiology of disease.

  4. High frequency resonant waveguide grating imager for assessing drug-induced cardiotoxicity

    Science.gov (United States)

    Ferrie, Ann M.; Wu, Qi; Deichmann, Oberon D.; Fang, Ye

    2014-05-01

    We report a high-frequency resonant waveguide grating imager for assessing compound-induced cardiotoxicity. The imager sweeps the wavelength range from 823 nm to 838 nm every 3 s to identify and monitor compound-induced shifts in resonance wavelength and then switch to the intensity-imaging mode to detect the beating rhythm and proarrhythmic effects of compounds on induced pluripotent stem cell-derived cardiomyocytes. This opens possibility to study cardiovascular biology and compound-induced cardiotoxicity.

  5. Increased low- and high-frequency oscillatory activity in the prefrontal cortex of fibromyalgia patients

    Directory of Open Access Journals (Sweden)

    Manyoel eLim

    2016-03-01

    Full Text Available Recent human neuroimaging studies have suggested that fibromyalgia (FM, a chronic widespread pain disorder, exhibits altered thalamic structure and function. Since the thalamus has extensive reciprocal connection with the cortex, structural and functional thalamic alterations in FM might be linked to aberrant thalamocortical oscillation. This study investigated the presence of abnormal brain rhythmicity in low- and high-frequency bands during resting state in patients with FM and their relationship to clinical pain symptom. Spontaneous magnetoencephalography activity was recorded in 18 females with FM and 18 age- and sex-matched healthy control subjects. The most remarkable finding was that FM patients had general increases in theta, beta and gamma power along with a slowing of the dominant alpha peak. Increased spectral powers in the theta-band were primarily localized to the left dorsolateral prefrontal (DLPFC and orbitofrontal cortex (OFC. Beta and gamma over-activation were localized to insular, primary motor and primary and secondary somatosensory cortices, as well as the DLPFC and OFC. Furthermore, enhanced high-frequency oscillatory activities in the DLPFC and OFC were associated with higher affective pain scores in patients with FM. Our results demonstrate that FM patients feature enhanced low- and high-frequency oscillatory activity in the brain areas related to cognitive and emotional modulation of pain. Increased low- and high-frequency activity of the prefrontal cortex may contribute to persistent perception of pain in FM. Therapeutic intervention based on manipulating neural oscillation to restore normal thalamocortical rhythmicity may be beneficial to pain relief in FM.

  6. Switching transients in high-frequency high-power converters using power MOSFET's

    Science.gov (United States)

    Sloane, T. H.; Owen, H. A., Jr.; Wilson, T. G.

    1979-01-01

    The use of MOSFETs in a high-frequency high-power dc-to-dc converter is investigated. Consideration is given to the phenomena associated with the paralleling of MOSFETs and to the effect of stray circuit inductances on the converter circuit performance. Analytical relationships between various time constants during the turning-on and turning-off intervals are derived which provide estimates of plateau and peak levels during these intervals.

  7. Intracerebrally recorded high frequency oscillations: Simple visual assessment versus automated detection

    Czech Academy of Sciences Publication Activity Database

    Pail, M.; Halámek, Josef; Daniel, P.; Kuba, R.; Tyrlíková, I.; Chrastina, J.; Jurák, Pavel; Rektor, I.; Brázdil, M.

    2013-01-01

    Roč. 124, č. 10 (2013), s. 1935-1942 ISSN 1388-2457 R&D Projects: GA ČR GAP103/11/0933; GA MŠk ED0017/01/01 Institutional support: RVO:68081731 Keywords : High frequency oscillations * Spikes * Ripples * Temporal lobe epilepsy * Extratemporal lobe epilepsy * Seizure onset zone * Epileptogenic zone Subject RIV: FH - Neurology Impact factor: 2.979, year: 2013

  8. Control of extracellular cleavage of ProBDNF by high frequency neuronal activity

    OpenAIRE

    Nagappan, Guhan; Zaitsev, Eugene; Senatorov, Vladimir V.; Yang, Jianmin; Hempstead, Barbara L.; Lu, Bai

    2009-01-01

    Pro- and mature neurotrophins often elicit opposing biological effects. For example, mature brain-derived neurotrophic factor (mBDNF) is critical for long-term potentiation induced by high-frequency stimulation, whereas proBDNF facilitate long-term depression induced by low-frequency stimulation. Because mBDNF is derived from proBDNF by endoproteolytic cleavage, mechanisms regulating the cleavage of proBDNF may control the direction of BDNF regulation. Using methods that selectively detect pr...

  9. High Frequency AC Inductor Analysis and Design for Dual Active Bridge (DAB) Converters

    DEFF Research Database (Denmark)

    Zhang, Zhe; Andersen, Michael A. E.

    2016-01-01

    The dual active bridge (DAB) converter is an isolated bidirectional dc-dc topology which is the most critical part for the power conversion systems such as solid-state transformers (SST). This paper focuses on analysis and design of high frequency ac inductors which are the power interfacing...... the core loss and the winding loss are almost equal is selected as the optimal one. The experimental results are presented to verify the validity of the analysis and design....

  10. A study of the high-frequency hearing thresholds of dentistry professionals

    Directory of Open Access Journals (Sweden)

    Lopes, Andréa Cintra

    2012-01-01

    Full Text Available Introduction: In the dentistry practice, dentists are exposed to harmful effects caused by several factors, such as the noise produced by their work instruments. In 1959, the American Dental Association recommended periodical hearing assessments and the use of ear protectors. Aquiring more information regarding dentists', dental nurses', and prosthodontists' hearing abilities is necessary to propose prevention measures and early treatment strategies. Objective: To investigate the auditory thresholds of dentists, dental nurses, and prosthodontists. Method: In this clinical and experimental study, 44 dentists (Group I; GI, 36 dental nurses (Group II; GII, and 28 prosthodontists (Group III; GIII were included, , with a total of 108 professionals. The procedures that were performed included a specific interview, ear canal inspection, conventional and high-frequency threshold audiometry, a speech reception threshold test, and an acoustic impedance test. Results: In the 3 groups that were tested, the comparison between the mean hearing thresholds provided evidence of worsened hearing ability relative to the increase in frequency. For the tritonal mean at 500 to 2,000 Hz and 3,000 to 6,000 Hz, GIII presented the worst thresholds. For the mean of the high frequencies (9,000 and 16,000 Hz, GII presented the worst thresholds. Conclusion: The conventional hearing threshold evaluation did not demonstrate alterations in the 3 groups that were tested; however, the complementary tests such as high-frequency audiometry provided greater efficacy in the early detection of hearing problems, since this population's hearing loss impaired hearing ability at frequencies that are not tested by the conventional tests. Therefore, we emphasize the need of utilizing high-frequency threshold audiometry in the hearing assessment routine in combination with other audiological tests.

  11. High-frequency Audiometry Hearing on Monitoring of Individuals Exposed to Occupational Noise: A Systematic Review

    Science.gov (United States)

    Antonioli, Cleonice Aparecida Silva; Momensohn-Santos, Teresa Maria; Benaglia, Tatiana Aparecida Silva

    2015-01-01

    Introduction  The literature reports on high-frequency audiometry as one of the exams used on hearing monitoring of individuals exposed to high sound pressure in their work environment, due to the method́s greater sensitivity in early identification of hearing loss caused by noise. The frequencies that compose the exam are generally between 9 KHz and 20KHz, depending on the equipment. Objective  This study aims to perform a retrospective and secondary systematic revision of publications on high-frequency audiometry on hearing monitoring of individuals exposed to occupational noise. Data Synthesis  This systematic revision followed the methodology proposed in the Cochrane Handbook, focusing on the question: “Is High-frequency Audiometry more sensitive than Conventional Audiometry in the screening of early hearing loss individuals exposed to occupational noise?” The search was based on PubMed data, Base, Web of Science (Capes), Biblioteca Virtual em Saúde (BVS), and in the references cited in identified and selected articles. The search resulted in 6059 articles in total. Of these, only six studies were compatible with the criteria proposed in this study. Conclusion  The performed meta-analysis does not definitively answer the study's proposed question. It indicates that the 16 KHz high frequency audiometry (HFA) frequency is sensitive in early identification of hearing loss in the control group (medium difference (MD = 8.33)), as well as the 4 KHz frequency (CA), this one being a little less expressive (MD = 5.72). Thus, others studies are necessary to confirm the HFA importance for the early screening of hearing loss on individuals exposed to noise at the workplace. PMID:27413413

  12. Rapid analysis & design methodologies of High-Frequency LCLC Resonant Inverter as Electrodeless Fluorescent Lamp Ballast

    OpenAIRE

    Ang, Y A; Stone, D A; Bingham, Chris; Foster, M

    2007-01-01

    The papers presents methodologies for the analysis of 4th-order LCLC resonant power converters operating at 2.63 MHz as fluorescent lamp ballasts, where high frequency operation facilitates capacitive discharge into the tube, with near resonance operation at high load quality factor enabling high efficiency. State-variable dynamic descriptions of the converter are employed to rapidly determine the steady-state cyclic behaviour of the ballast during nominal operation. Simulation and experiment...

  13. High-Frequency Percussive Ventilation and Low Tidal Volume Ventilation in Burns: A Randomized Controlled Trial

    Science.gov (United States)

    2010-01-01

    care units, high-frequency percussive ventilation is preferentially used to provide mechanical ventilation in support of patients with acute lung... mechanical ventilation were admitted to the burn intensive care unit. The study was conducted over a 3-yr period between April 2006 and May 2009. This trial...was registered with ClinicalTrials.gov as NCT00351741. Interventions: Subjects were randomly assigned to receive mechanical ventilation through a high

  14. Testing of Dependencies between Stock Returns and Trading Volume by High Frequency Data

    OpenAIRE

    Piotr Gurgul; Robert Syrek

    2013-01-01

    This paper is concerned with a dependence analysis of returns, return volatility and trading volume for five companies listed on the Vienna Stock Exchange and five from the Warsaw Stock Exchange. Taking into account high frequency data for these companies, tests based on a comparison of Bernstein copula densities using the Hellinger distance were conducted. The paper presents some patterns of causal and other relationships between stock returns, realized volatility and expected and unexpected...

  15. Power conversion distribution system using a resonant high-frequency AC link

    Science.gov (United States)

    Sood, P. K.; Lipo, T. A.

    1986-01-01

    Static power conversion systems based on a resonant high frequency (HF) link offers a significant reduction in the size and weight of the equipment over that achieved with conventional approaches, especially when multiple sources and loads are to be integrated. A faster system response and absence of audible noise are the other principal characteristics of such systems. A conversion configuration based on a HF link which is suitable for applications requiring distributed power is proposed.

  16. High Frequency Magneto Dielectric Effects In Self Assembled Ferrite Ferroelectric Core Shell Nanoparticles

    Science.gov (United States)

    2014-09-10

    estimate the magneto-capacitance effect in BTO or PZT films on substrates of ferromagnetic alloys.25 This work is on the observation and theory of MDE...The sample shows ferromagnetic behavior with hysteresis and remnance and the magnetization compared favorably with reported value for...samples. A strong ME coupling was also evident from H-tuning of dielectric resonance in the composites. A theory for the high frequency magneto

  17. A powerful electrohydrodynamic flow generated by a high-frequency dielectric barrier discharge in a gas

    Energy Technology Data Exchange (ETDEWEB)

    Nebogatkin, S. V.; Rebrov, I. E.; Khomich, V. Yu.; Yamshchikov, V. A., E-mail: yamschikov52@mail.ru [Russian Academy of Sciences, Institute for Electrophysics and Electric Power (Russian Federation)

    2016-01-15

    Theoretical and experimental studies of an electrohydrodynamic flow induced by a high-frequency dielectric barrier discharge distributed over a dielectric surface in a gas have been conducted. Dependences of the ion current, the gas flow velocity, and the spatial distributions thereof on the parameters of the power supply of the plasma ion emitter and an external electric field determined by the collector grid voltage have been described.

  18. Prophylactic Use of High-Frequency Percussive Ventilation in Patients with Inhalation Injury,

    Science.gov (United States)

    1991-06-01

    historically occurred in 38% of clinical criteria for mechanical ventilation . High-frequency per- all patients with inhalation injury but in only 8% of those... Mechanical Ventilator ’ Support Patient Population I. Respiratory rate > 35/min 2. Vital capacity < 15 mL/kg All adult patients admitted to the United...to baseline approxi- ments for intubation and mechanical ventilatory support mately 2 less than the intermittant mandatory ventilation listed in Table

  19. Mechanical ventilation in the newborn; a simplified approach. Part 2: High-frequency ventilation.

    Science.gov (United States)

    Muhlethaler, Vincent; Malcolm, Girvan

    2014-10-01

    High frequency oscillatory ventilation (HFOV) is becoming an increasingly popular intervention in the neonatal intensive care unit. This article will attempt to explain the principles of HFOV. It is inherently more difficult to become skilled in this technique than in other forms of mechanical ventilation, so caution is warranted. © 2010 The Author. Journal of Paediatrics and Child Health © 2010 Paediatrics and Child Health Division (Royal Australasian College of Physicians).

  20. A cost effective harmonic cancellation method for high frequency Silicon Carbide MOSFET based single phase inverter

    OpenAIRE

    Harrasi, A; Zobaa, AF

    2016-01-01

    This paper introduces a combinational modulation method to be used in classic full-bridge single phase inverters. The proposed method eliminates even-order harmonics at PWM stage in control section unlike the conventional method of even order harmonic cancelation in power stage and offers a cost effective design by switching one leg at high frequency. Using a low cost Digital Signal Controller (DSC) platform, regular sampling technique based on real time calculation was employed to verify the...

  1. High-frequency Audiometry Hearing on Monitoring of Individuals Exposed to Occupational Noise: A Systematic Review

    Directory of Open Access Journals (Sweden)

    Antonioli, Cleonice Aparecida Silva

    2015-12-01

    Full Text Available Introduction The literature reports on high-frequency audiometry as one of the exams used on hearing monitoring of individuals exposed to high sound pressure in their work environment, due to the method́s greater sensitivity in early identification of hearing loss caused by noise. The frequencies that compose the exam are generally between 9 KHz and 20KHz, depending on the equipment. Objective This study aims to perform a retrospective and secondary systematic revision of publications on high-frequency audiometry on hearing monitoring of individuals exposed to occupational noise. Data Synthesis This systematic revision followed the methodology proposed in the Cochrane Handbook, focusing on the question: “Is High-frequency Audiometry more sensitive than Conventional Audiometry in the screening of early hearing loss individuals exposed to occupational noise?” The search was based on PubMed data, Base, Web of Science (Capes, Biblioteca Virtual em Saúde (BVS, and in the references cited in identified and selected articles. The search resulted in 6059 articles in total. Of these, only six studies were compatible with the criteria proposed in this study. Conclusion The performed meta-analysis does not definitively answer the study's proposed question. It indicates that the 16 KHz high frequency audiometry (HFA frequency is sensitive in early identification of hearing loss in the control group (medium difference (MD = 8.33, as well as the 4 KHz frequency (CA, this one being a little less expressive (MD = 5.72. Thus, others studies are necessary to confirm the HFA importance for the early screening of hearing loss on individuals exposed to noise at the workplace.

  2. Tesla’s high voltage and high frequency generators with oscillatory circuits

    OpenAIRE

    Cvetić Jovan M.

    2016-01-01

    The principles that represent the basics of the work of the high voltage and high frequency generator with oscillating circuits will be discussed. Until 1891, Tesla made and used mechanical generators with a large number of extruded poles for the frequencies up to about 20 kHz. The first electric generators based on a new principle of a weakly coupled oscillatory circuits he used for the wireless signal transmission, for the study of the discharges in vacuu...

  3. Proton-irradiation technology for high-frequency high-current silicon welding diode manufacturing

    Science.gov (United States)

    Lagov, P. B.; Drenin, A. S.; Zinoviev, M. A.

    2017-05-01

    Different proton irradiation regimes were tested to provide more than 20 kHz-frequency, soft reverse recovery “snap-less” behavior, low forward voltage drop and leakage current for 50 mm diameter 7 kA/400 V welding diode Al/Si/Mo structure. Silicon diode with such parameters is very suitable for high frequency resistance welding machines of new generation for robotic welding.

  4. Intra-operative high frequency ultrasound improves surgery of intramedullary cavernous malformations.

    Science.gov (United States)

    Bozinov, Oliver; Burkhardt, Jan-Karl; Woernle, Christoph M; Hagel, Vincent; Ulrich, Nils H; Krayenbühl, Niklaus; Bertalanffy, Helmut

    2012-04-01

    Intra-operative ultrasound (ioUS) is a very useful tool in surgery of spinal lesions. Here we focus on modern ioUS to analyze its use for localisation, visualisation and resection control in intramedullary cavernous malformations (IMCM). A series of 35 consecutive intradural lesions were operated in our hospital in a time period of 24 months using modern ioUS with a high frequency 7-15 MHz transducer and a true real time 3D transducer (both Phillips iU 22 ultrasound system). Six of those cases were treated with the admitting diagnosis of a deep IMCM (two cervical, four thoracic lesions). IoUS images were performed before and after the IMCM resection. Pre-operative and early postoperative MRI images were performed in all patients. In all six IMCM cases a complete removal of the lesion was achieved microsurgically resulting in an improved neurological status of all patients. High frequency ioUS emerged to be a very useful tool during surgery for localization and visualization. Excellent resection control by ultrasound was possible in three cases. Minor resolution of true real time 3D ioUS decreases the actual advantage of simultaneous reconstruction in two planes. High frequency ioUS is the best choice for intra-operative imaging in deep IMCM to localize and to visualize the lesion and to plan the perfect surgical approach. Additionally, high frequency ioUS is suitable for intra-operative resection control of the lesion in selected IMCM cases.

  5. High-frequency Audiometry Hearing on Monitoring of Individuals Exposed to Occupational Noise: A Systematic Review.

    Science.gov (United States)

    Antonioli, Cleonice Aparecida Silva; Momensohn-Santos, Teresa Maria; Benaglia, Tatiana Aparecida Silva

    2016-07-01

    The literature reports on high-frequency audiometry as one of the exams used on hearing monitoring of individuals exposed to high sound pressure in their work environment, due to the method́s greater sensitivity in early identification of hearing loss caused by noise. The frequencies that compose the exam are generally between 9 KHz and 20KHz, depending on the equipment. This study aims to perform a retrospective and secondary systematic revision of publications on high-frequency audiometry on hearing monitoring of individuals exposed to occupational noise. This systematic revision followed the methodology proposed in the Cochrane Handbook, focusing on the question: "Is High-frequency Audiometry more sensitive than Conventional Audiometry in the screening of early hearing loss individuals exposed to occupational noise?" The search was based on PubMed data, Base, Web of Science (Capes), Biblioteca Virtual em Saúde (BVS), and in the references cited in identified and selected articles. The search resulted in 6059 articles in total. Of these, only six studies were compatible with the criteria proposed in this study. The performed meta-analysis does not definitively answer the study's proposed question. It indicates that the 16 KHz high frequency audiometry (HFA) frequency is sensitive in early identification of hearing loss in the control group (medium difference (MD = 8.33)), as well as the 4 KHz frequency (CA), this one being a little less expressive (MD = 5.72). Thus, others studies are necessary to confirm the HFA importance for the early screening of hearing loss on individuals exposed to noise at the workplace.

  6. Backscattering analysis of high frequency ultrasonic imaging for ultrasound-guided breast biopsy

    Science.gov (United States)

    Cummins, Thomas; Akiyama, Takahiro; Lee, Changyang; Martin, Sue E.; Shung, K. Kirk

    2017-03-01

    A new ultrasound-guided breast biopsy technique is proposed. The technique utilizes conventional ultrasound guidance coupled with a high frequency embedded ultrasound array located within the biopsy needle to improve the accuracy in breast cancer diagnosis.1 The array within the needle is intended to be used to detect micro- calcifications indicative of early breast cancers such as ductal carcinoma in situ (DCIS). Backscattering analysis has the potential to characterize tissues to improve localization of lesions. This paper describes initial results of the application of backscattering analysis of breast biopsy tissue specimens and shows the usefulness of high frequency ultrasound for the new biopsy related technique. Ultrasound echoes of ex-vivo breast biopsy tissue specimens were acquired by using a single-element transducer with a bandwidth from 41 MHz to 88 MHz utilizing a UBM methodology, and the backscattering coefficients were calculated. These values as well as B-mode image data were mapped in 2D and matched with each pathology image for the identification of tissue type for the comparison to the pathology images corresponding to each plane. Microcalcifications were significantly distinguished from normal tissue. Adenocarcinoma was also successfully differentiated from adipose tissue. These results indicate that backscattering analysis is able to quantitatively distinguish tissues into normal and abnormal, which should help radiologists locate abnormal areas during the proposed ultrasound-guided breast biopsy with high frequency ultrasound.

  7. Potential Sources of High Frequency and Biphonic Vocalization in the Dhole (Cuon alpinus.

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    Roland Frey

    Full Text Available Biphonation, i.e. two independent fundamental frequencies in a call spectrum, is a prominent feature of vocal activity in dog-like canids. Dog-like canids can produce a low (f0 and a high (g0 fundamental frequency simultaneously. In contrast, fox-like canids are only capable of producing the low fundamental frequency (f0. Using a comparative anatomical approach for revealing macroscopic structures potentially responsible for canid biphonation, we investigated the vocal anatomy for 4 (1 male, 3 female captive dholes (Cuon alpinus and for 2 (1 male, 1 female wild red fox (Vulpes vulpes. In addition, we analyzed the acoustic structure of vocalizations in the same dholes that served postmortem as specimens for the anatomical investigation. All study dholes produced both high-frequency and biphonic calls. The anatomical reconstructions revealed that the vocal morphologies of the dhole are very similar to those of the red fox. These results suggest that the high-frequency and biphonic calls in dog-like canids can be produced without specific anatomical adaptations of the sound-producing structures. We discuss possible production modes for the high-frequency and biphonic calls involving laryngeal and nasal structures.

  8. Gentamicin rapidly inhibits mitochondrial metabolism in high-frequency cochlear outer hair cells.

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    Heather C Jensen-Smith

    Full Text Available Aminoglycosides (AG, including gentamicin (GM, are the most frequently used antibiotics in the world and are proposed to cause irreversible cochlear damage and hearing loss (HL in 1/4 of the patients receiving these life-saving drugs. Akin to the results of AG ototoxicity studies, high-frequency, basal turn outer hair cells (OHCs preferentially succumb to multiple HL pathologies while inner hair cells (IHCs are much more resilient. To determine if endogenous differences in IHC and OHC mitochondrial metabolism dictate differential sensitivities to AG-induced HL, IHC- and OHC-specific changes in mitochondrial reduced nicotinamide adenine dinucleotide (NADH fluorescence during acute (1 h GM treatment were compared. GM-mediated decreases in NADH fluorescence and succinate dehydrogenase activity were observed shortly after GM application. High-frequency basal turn OHCs were found to be metabolically biased to rapidly respond to alterations in their microenvironment including GM and elevated glucose exposures. These metabolic biases may predispose high-frequency OHCs to preferentially produce cell-damaging reactive oxygen species during traumatic challenge. Noise-induced and age-related HL pathologies share key characteristics with AG ototoxicity, including preferential OHC loss and reactive oxygen species production. Data from this report highlight the need to address the role of mitochondrial metabolism in regulating AG ototoxicity and the need to illuminate how fundamental differences in IHC and OHC metabolism may dictate differences in HC fate during multiple HL pathologies.

  9. Efficacy of high frequency ultrasound in postoperative evaluation of carpal tunnel syndrome treatment

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    Katarzyna Kapuścińska

    2016-03-01

    Full Text Available Carpal tunnel syndrome (CTS is the most common entrapment neuropathy and a frequent cause of sick leave because of work-related hand overload. The main treatment is operation. Aim: The aim of the study is to assess the usefulness of high frequency ultrasound in the postoperative evaluation of CTS treatment efficacy. Material and methods: Sixty-two patients (50 women and 12 men aged 28–70, mean age 55.2 underwent surgical treatment of CTS. Ultrasound examinations of the wrist in all carpal tunnel sufferers were performed 3 months after the procedure with the use of a high frequency broadband linear array transducer (6–18 MHz, using 18 MHz band of MyLab 70/Esaote. On the basis of the collected data, the author has performed multiple analyses to confirm the usefulness of ultrasound imaging for postoperative evaluation of CTS treatment efficacy. Results: Among all 62 patients, 3 months after surgical median nerve decompression: in 40 patients, CTS symptoms subsided completely, and sonographic evaluation did not show median nerve entrapment signs; in 9 patients, CTS symptoms persisted or exacerbated, and ultrasound proved nerve compression revealing preserved flexor retinaculum fibers; in 13 patients, scar tissue symptoms occurred, and in 5 of them CTS did not subside completely (although ultrasound showed no signs of compression. Conclusions: Ultrasound imaging with the use of a high frequency transducer is a valuable diagnostic tool for postoperative assessment of CTS treatment efficacy.

  10. Design of Plasma Generator Driven by High-frequency High-voltage Power Supply

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    C. Yong-Nong

    2013-04-01

    Full Text Available In this research, a high-frequency high-voltage power supply designed for plasma generator is presented. The power supply mainly consists of a series resonant converter with a high-frequency high-voltage boost transformer. Due to the indispensable high-voltage inheritance in the operation of plasma generator, the analysis of transformer need considering not only winding resistance, leakage inductance, magnetizing inductance, and core-loss resistance, but also parasitic capacitance resulted from the insulation wrappings on the high-voltage side. This research exhibits a simple approach to measuring equivalent circuit parameters of the high-frequency, high-voltage transformer with stray capacitance being introduced into the conventional modeling. The proposed modeling scheme provides not only a precise measurement procedure but also effective design information for series-load resonant converter. The plasma discharging plate is designed as part of the electric circuit in the series load-resonant converter and the circuit model of the plasma discharging plate is also conducted as well. Thus, the overall model of the high-voltage plasma generator is built and the designing procedures for appropriate selections of the corresponding resonant-circuit parameters can be established. Finally, a high-voltage plasma generator with 220V, 60Hz, and 1kW input, along with a 22 kHz and over 8kV output, is realized and implemented.

  11. Design of Plasma Generator Driven by High-frequency High-voltage Power Supply

    Directory of Open Access Journals (Sweden)

    C. Yong-Nong

    2013-03-01

    Full Text Available In this research, a high-frequency high-voltage power supply designed for plasma generator is presented. The powersupply mainly consists of a series resonant converter with a high-frequency high-voltage boost transformer. Due to theindispensable high-voltage inheritance in the operation of plasma generator, the analysis of transformer needconsidering not only winding resistance, leakage inductance, magnetizing inductance, and core-loss resistance, butalso parasitic capacitance resulted from the insulation wrappings on the high-voltage side. This research exhibits asimple approach to measuring equivalent circuit parameters of the high-frequency, high-voltage transformer with straycapacitance being introduced into the conventional modeling. The proposed modeling scheme provides not only aprecise measurement procedure but also effective design information for series-load resonant converter. The plasmadischarging plate is designed as part of the electric circuit in the series load-resonant converter and the circuit modelof the plasma discharging plate is also conducted as well. Thus, the overall model of the high-voltage plasmagenerator is built and the designing procedures for appropriate selections of the corresponding resonant-circuitparameters can be established. Finally, a high-voltage plasma generator with 220V, 60Hz, and 1kW input, along witha 22 kHz and over 8kV output, is realized and implemented.

  12. The Influence of High-Frequency Envelope Information on Low-Frequency Vowel Identification in Noise.

    Science.gov (United States)

    Schubotz, Wiebke; Brand, Thomas; Kollmeier, Birger; Ewert, Stephan D

    2016-01-01

    Vowel identification in noise using consonant-vowel-consonant (CVC) logatomes was used to investigate a possible interplay of speech information from different frequency regions. It was hypothesized that the periodicity conveyed by the temporal envelope of a high frequency stimulus can enhance the use of the information carried by auditory channels in the low-frequency region that share the same periodicity. It was further hypothesized that this acts as a strobe-like mechanism and would increase the signal-to-noise ratio for the voiced parts of the CVCs. In a first experiment, different high-frequency cues were provided to test this hypothesis, whereas a second experiment examined more closely the role of amplitude modulations and intact phase information within the high-frequency region (4-8 kHz). CVCs were either natural or vocoded speech (both limited to a low-pass cutoff-frequency of 2.5 kHz) and were presented in stationary 3-kHz low-pass filtered masking noise. The experimental results did not support the hypothesized use of periodicity information for aiding low-frequency perception.

  13. The Influence of High-Frequency Envelope Information on Low-Frequency Vowel Identification in Noise.

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    Wiebke Schubotz

    Full Text Available Vowel identification in noise using consonant-vowel-consonant (CVC logatomes was used to investigate a possible interplay of speech information from different frequency regions. It was hypothesized that the periodicity conveyed by the temporal envelope of a high frequency stimulus can enhance the use of the information carried by auditory channels in the low-frequency region that share the same periodicity. It was further hypothesized that this acts as a strobe-like mechanism and would increase the signal-to-noise ratio for the voiced parts of the CVCs. In a first experiment, different high-frequency cues were provided to test this hypothesis, whereas a second experiment examined more closely the role of amplitude modulations and intact phase information within the high-frequency region (4-8 kHz. CVCs were either natural or vocoded speech (both limited to a low-pass cutoff-frequency of 2.5 kHz and were presented in stationary 3-kHz low-pass filtered masking noise. The experimental results did not support the hypothesized use of periodicity information for aiding low-frequency perception.

  14. An MRI-Compatible High Frequency AC Resistive Heating System for Homeothermic Maintenance in Small Animals.

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    Stuart Gilchrist

    Full Text Available To develop an MRI-compatible resistive heater, using high frequency alternating current (AC, for temperature maintenance of anaesthetised animals.An MRI-compatible resistive electrical heater was formed from narrow gauge wire connected to a high frequency (10-100 kHz AC power source. Multiple gradient echo images covering a range of echo times, and pulse-acquire spectra were acquired with the wire heater powered using high frequency AC or DC power sources and without any current flowing in order to assess the sensitivity of the MRI acquisitions to the presence of current flow through the heater wire. The efficacy of temperature maintenance using the AC heater was assessed by measuring rectal temperature immediately following induction of general anaesthesia for a period of 30 minutes in three different mice.Images and spectra acquired in the presence and absence of 50-100 kHz AC through the wire heater were indistinguishable, whereas DC power created field shifts and lineshape distortions. Temperature lost during induction of anaesthesia was recovered within approximately 20 minutes and a stable temperature was reached as the mouse's temperature approached the set target.The AC-powered wire heater maintains adequate heat input to the animal to maintain body temperature, and does not compromise image quality.

  15. High frequency switched-mode stimulation can evoke postsynaptic responses in cerebellar principal neurons

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    Marijn Van Dongen

    2015-03-01

    Full Text Available This paper investigates the efficacy of high frequency switched-mode neural stimulation. Instead of using a constant stimulation amplitude, the stimulus is switched on and off repeatedly with a high frequency (up to 100kHz duty cycled signal. By means of tissue modeling that includes the dynamic properties of both the tissue material as well as the axon membrane, it is first shown that switched-mode stimulation depolarizes the cell membrane in a similar way as classical constant amplitude stimulation.These findings are subsequently verified using in vitro experiments in which the response of a Purkinje cell is measured due to a stimulation signal in the molecular layer of the cerebellum of a mouse. For this purpose a stimulator circuit is developed that is able to produce a monophasic high frequency switched-mode stimulation signal. The results confirm the modeling by showing that switched-mode stimulation is able to induce similar responses in the Purkinje cell as classical stimulation using a constant current source. This conclusion opens up possibilities for novel stimulation designs that can improve the performance of the stimulator circuitry. Care has to be taken to avoid losses in the system due to the higher operating frequency.

  16. Effects of local high-frequency perturbation on a turbulent boundary layer by synthetic jet injection

    Science.gov (United States)

    Guo, Hao; Huang, Qian-Min; Liu, Pei-qing; Qu, Qiu-Lin

    2015-08-01

    An experimental study is performed to investigate the local high-frequency perturbation effects of a synthetic jet injection on a flat-plate turbulent boundary layer. Parameters of the synthetic jet are designed to force a high-frequency perturbation from a thin spanwise slot in the wall. In the test locations downstream of the slot, it is found that skin-friction is reduced by the perturbation, which is languishingly evolved downstream of the slot with corresponding influence on the near-wall regeneration mechanism of turbulent structures. The downstream slot region is divided into two regions due to the influence strength of the movement of spanwise vortices generated by the high-frequency perturbation. Interestingly, the variable interval time average technique is found to be disturbed by the existence of the spanwise vortices’ motion, especially in the region close to the slot. Similar results are obtained from the analysis of the probability density functions of the velocity fluctuation time derivatives, which is another indirect technique for detecting the enhancement or attenuation of streamwise vortices. However, both methods have shown consistent results with the skin-friction reduction mechanism in the far-away slot region. The main purpose of this paper is to remind researchers to be aware of the probable influence of spanwise vortices’ motion in wall-bounded turbulence control.

  17. Investigating DOC export dynamics using high-frequency instream concentration measurements

    Science.gov (United States)

    Oosterwoud, Marieke; Keller, Toralf; Musolff, Andreas; Frei, Sven; Park, Ji-Hyung; Fleckenstein, Jan H.

    2014-05-01

    Being able to monitor DOC concentrations using in-situ high frequency measurements makes it possible to better understand concentration-discharge behavior under different hydrological conditions. We developed a UV-Vis probe setup for modified/adapted use under field conditions. The quasi mobile probe setup allows a more flexible probe deployment. New or existing monitoring sites can easily be equipped for quasi-continuous monitoring or measurements can be performed at changing locations, without the need for additional infrastructure. We were able to gather high frequency data on DOC dynamics for one year in two streams in the Harz mountains in Germany. It proved that obtaining accurate DOC concentrations from the UV-Vis probes required frequent maintenance and probe calibration. The advantage of the setup over standard monitoring protocols becomes evident when comparing net exports over a year. In addition to mass improved balance calculations the high-frequency measurements can reveal intricate hysteretic relationships between discharge and concentrations that can provide valuable insights into the hydrologic dynamics and mechanisms that govern the delivery of DOC to the receiving waters. Measurements with similar probes from two additional catchments in Southern Germany and South Korea will be used to illustrate different discharge-concentration relationships and what can be learned from them about the hydrologic mechanisms that control the dynamics of DOC export.

  18. Design and fabrication of metal-insulator-metal diode for high frequency applications

    Science.gov (United States)

    Azad, Ibrahim; Ram, Manoj K.; Goswami, D. Yogi; Stefanakos, Elias

    2017-02-01

    Metal-insulator-metal (MIM) diodes play significant role in high speed electronics where high frequency rectification is needed. Quantum based tunneling mechanism helps MIM diodes to rectify at high frequency signals. Rectenna, antenna coupled MIM diodes are becoming popular due to their potential use as IR detectors and energy harvesters. Because of small active area, MIM diodes could easily be incorporated into integrated circuits (IC's). The objective of the work is to design and develop MIM diodes for high frequency rectification. In this work, thin insulating layer of ZnO was fabricated using Langmuir-Blodgett (LB) technique which facilitates ultrathin thin, uniform and pinhole free fabrication of insulating layer. The ZnO layer was synthesized from organic precursor of zinc acetate layer. The optimization in the LB technique of fabrication process led to fabricate MIM diodes with high non-linearity and sensitivity. Moreover, the top and bottom electrodes as well as active area of the diodes were patterned using UV-tunneling conduction mechanism. The highest sensitivity of the diode was measured around 37 (A/W), and the rectification ratio was found around 36 under low applied bias at +/-100 mV.

  19. Gender and vocal production mode discrimination using the high frequencies for speech and singing

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    Brian B Monson

    2014-10-01

    Full Text Available Humans routinely create acoustical energy at frequencies above 6 kHz during vocalization, but this frequency range is often not represented in communication devices and speech perception research. Recent advancements toward HD voice and extended bandwidth hearing aids have increased the interest in the high frequencies. The potential perceptual information provided by high-frequency energy (HFE is not well characterized. We found that humans can accomplish tasks of gender discrimination and vocal production mode discrimination (speech vs. singing when presented with acoustic stimuli containing only HFE at both amplified and normal levels. Performance in these tasks was robust in the presence of low-frequency masking noise. No substantial learning effect was observed. Listeners also were able to identify the sung and spoken text (excerpts from The Star-Spangled Banner with very few exposures. These results add to the increasing evidence that the high frequencies provide at least redundant information about the vocal signal, suggesting that its representation in communication devices (e.g., cell phones, hearing aids, and cochlear implants and speech/voice synthesizers could improve these devices and benefit normal-hearing and hearing-impaired listeners.

  20. Developing High-Frequency Quantitative Ultrasound Techniques to Characterize Three-Dimensional Engineered Tissues

    Science.gov (United States)

    Mercado, Karla Patricia E.

    Tissue engineering holds great promise for the repair or replacement of native tissues and organs. Further advancements in the fabrication of functional engineered tissues are partly dependent on developing new and improved technologies to monitor the properties of engineered tissues volumetrically, quantitatively, noninvasively, and nondestructively over time. Currently, engineered tissues are evaluated during fabrication using histology, biochemical assays, and direct mechanical tests. However, these techniques destroy tissue samples and, therefore, lack the capability for real-time, longitudinal monitoring. The research reported in this thesis developed nondestructive, noninvasive approaches to characterize the structural, biological, and mechanical properties of 3-D engineered tissues using high-frequency quantitative ultrasound and elastography technologies. A quantitative ultrasound technique, using a system-independent parameter known as the integrated backscatter coefficient (IBC), was employed to visualize and quantify structural properties of engineered tissues. Specifically, the IBC was demonstrated to estimate cell concentration and quantitatively detect differences in the microstructure of 3-D collagen hydrogels. Additionally, the feasibility of an ultrasound elastography technique called Single Tracking Location Acoustic Radiation Force Impulse (STL-ARFI) imaging was demonstrated for estimating the shear moduli of 3-D engineered tissues. High-frequency ultrasound techniques can be easily integrated into sterile environments necessary for tissue engineering. Furthermore, these high-frequency quantitative ultrasound techniques can enable noninvasive, volumetric characterization of the structural, biological, and mechanical properties of engineered tissues during fabrication and post-implantation.