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  • Springer  (75)
  • 1990-1994  (74)
  • 1940-1944  (1)
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  • 1
    Electronic Resource
    Electronic Resource
    Sieve algorithms for perfect power testing (1993)
    Springer
    Algorithmica 9 (1993), S. 313-328 
    Details
    ISSN: 1432-0541
    Keywords: Perfect powers ; Number theoretic algorithms ; Riemann hypothesis ; Newton's method ; Sieve algorithms ; Parallel algorithms ; Average-case analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract A positive integern is a perfect power if there exist integersx andk, both at least 2, such thatn=x k . The usual algorithm to recognize perfect powers computes approximatekth roots fork≤log 2 n, and runs in time O(log3 n log log logn). First we improve this worst-case running time toO(log3 n) by using a modified Newton's method to compute approximatekth roots. Parallelizing this gives anNC 2 algorithm. Second, we present a sieve algorithm that avoidskth-root computations by seeing if the inputn is a perfectkth power modulo small primes. Ifn is chosen uniformly from a large enough interval, the average running time isO(log2 n). Third, we incorporate trial division to give a sieve algorithm with an average running time ofO(log2 n/log2 logn) and a median running time ofO(logn). The two sieve algorithms use a precomputed table of small primes. We give a heuristic argument and computational evidence that the largest prime needed in this table is (logn)1+O(1); assuming the Extended Riemann Hypothesis, primes up to (logn)2+O(1) suffice. The table can be computed in time roughly proportional to the largest prime it contains. We also present computational results indicating that our sieve algorithms perform extremely well in practice.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01228507
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  • 2
    Electronic Resource
    Electronic Resource
    Potential nitrate pollution of groundwater in Germany: A supraregional differentiated model (1994)
    Springer
    Environmental geology 24 (1994), S. 1-6 
    Details
    ISSN: 1432-0495
    Keywords: Nitrate ; Groundwater ; Modeling ; Denitrification ; Nitrogen balance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Implemented on behalf of the Federal Ministry for Research and Technology (BMFT), a model is developed to trace the nutrient flow of nitrate in the soil and the groundwater on a supraregional scale. Research work is intended to indicate regionally differentiated hazardous potentials and thereby provide a basis for recommending comprehensive measures to protect groundwater in Germany. The adaption of the model to the hydrogeological and agricultural conditions of other states is possible in principle. This article focuses on the hydrogeological model parts. A high nitrate pollution of groundwater can be expected in all regions with intensive agricultural use of the topsoil. In particular, groundwater in solid rock areas is susceptible to nitrate pollution. There a rapid groundwater turnover and thus a short residence time for the groundwater in the aquifer is typical. Oxidizing aquifer conditions usually prevail in solid rock aquifers, preventing nitrate degradation. In many loose rock areas, in contrast, the groundwater has a low flow velocity and a long residence time in the aquifer. Because of a lack of free oxygen, a complete degradation of nitrate can occur, as long as iron sulfide compounds and/or organic carbon are available in the aquifer. A more detailed presentation of the whole research work is given in Wendland et al. (1993).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00768070
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  • 3
    Electronic Resource
    Electronic Resource
    Hunter syndrome in Jews in Israel: further evidence for prenatal selection favoring the Hunter allele (1991)
    Springer
    Human genetics 〈Berlin〉 86 (1991), S. 531-533 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Among all the Jewish families with Hunter patients in Israel, 10 were Ashkenazi or Moroccan in origin. In those families, there was a paucity of new mutations. In addition, a significant deviation of the segregation ratio between the Hunter gene and the normal allele was demonstrated among the offspring of heterozygous mothers or siblings of affected children in these families. These results confirm and extend our previous observations suggesting selection in favor of the X chromosome carrying the Hunter allele among Ashkenazi and Moroccan Jews.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00194650
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  • 4
    Electronic Resource
    Electronic Resource
    Natural killer lectin-like receptors have divergent carboxyl-termini, distinct from C-type lectins (1994)
    Springer
    Immunogenetics 39 (1994), S. 218-218 
    Details
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00241264
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  • 5
    Electronic Resource
    Electronic Resource
    Heterogeneity of HLA genetic factors in IDDM susceptibility (1990)
    Springer
    Immunogenetics 31 (1990), S. 233-240 
    Details
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The association of certain HLA-D alleles with insulin-dependent diabetes mellitus (IDDM) is well known. One hundred and sixty-one non-related diabetic individuals and 142 non-related healthy controls were typed for the HLA DR-DQw-Dw association, using a restriction fragment length polymorphism (RFLP) typing method that combines three probe/enzyme systems: DRB/Taq I, DQB/Taq I, and DQB/Bam HI. Comparison of frequencies in both diabetics and controls confirms previous results in terms of HLA class II and IDDM association. Moreover, we have found that DR3/4 heterozygous individuals are more susceptible to IDDM when they are also Dw25 (associated with B18) than when they are Dw24 (associated with B8). Using oligonucleotide dot-blot hybridizations we analyzed the HLA-DQB1 sequence of DR3, Dw24 and DR3, Dw25 homozygous individuals, and we found no difference at position 57 between these two DR3-carrying haplotypes. This observation points to the heterogeneity of HLA genetic factors in IDDM susceptibility.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00204893
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  • 6
    Electronic Resource
    Electronic Resource
    Physical fine mapping of genes underlying X-linked deafness and non fra(X)-X-linked mental retardation at Xq21 (1992)
    Springer
    Human genetics 〈Berlin〉 89 (1992), S. 620-624 
    Details
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Linkage studies and cytogenetically visible deletions associated with nonspecific X-linked mental retardation (XLMR) and a specific form of deafness (DFN3) have indicated that the genes responsible for these disorders are located at Xq21. Using DNA probes from this region, we have studied several overlapping deletions spanning different parts of Xq21. This has enabled us to assign the DFN3 gene and a gene for nonspecific XLMR to an interval that encompasses the locus DXS232 and that is flanked by DXS26 and DXS121.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00221950
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  • 7
    Electronic Resource
    Electronic Resource
    Genomic structure of NKG5, a human NK and T cell-specific activation gene (1993)
    Springer
    Immunogenetics 37 (1993), S. 102-107 
    Details
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We reported previously the isolation of a cDNA clone, designated NKG5, encoding a secreted protein that is expressed only in natural killer and T cells and is strongly upregulated upon cell activation. In this report we have isolated the NKG5 gene from a human placental genomic library and sequenced the gene and two kilobases of 5'-flanking DNA. Comparison with the cDNA sequence reveals that the NKG5 gene consists of five exons and four introns. Intron 1 contains a DNA segment that was reported to occur as an exon in 519, a closely related cDNA clone that was isolated from a T-cell library. This result indicates that NKG5 and 519 are alternative splicing products of a single gene. The 5′-flanking region of the NKG5 gene was analyzed for homology with the promoter regions of cytokines and other activation-induced genes showing lymphocyte-specific expression. Several segments displaying sequence similarity were identified. We also identified numerous sequence elements that have strong similarity to known binding sites for transcriptional regulatory proteins including T-cell-specific and activation-specific regulatory factors. These findings are consistent with the cell-specific expression and the tight regulatory control that is observed for the NKG5 gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216832
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  • 8
    Electronic Resource
    Electronic Resource
    A multigene family on human chromosome 12 encodes natural killer-cell lectins (1993)
    Springer
    Immunogenetics 37 (1993), S. 455-460 
    Details
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We previously isolated a series of cDNA clones designated NKG2-A, B, C, and D from a human natural killer (NK) cell library. These transcripts encode a family of type II integral membrane proteins having an extracellular Ca2+-dependent lectin domain. The predicted peptides share structural similarities and amino acid sequence similarity with known receptor molecules. In this report, the genomic organization and mRNA expression of each of the genes were studied by using transcript-specific probes. Southern blot experiments reveal that the probes cross-hybridize with a maximum of five genes at high stringency. By probing a Southern blot prepared from a series of hamster/human hybrid somatic cell lines, we demonstrated that all of the hybridizing fragments occur on human chromosome 12. No gene rearrangement and little restriction fragment length polymorphism (RFLP) was observed with these probes. mRNA expression of the NKG2 genes occured in NK cells and some T cells but not in other hematopoietic cell types or in other tissues tested. Each of the transcripts occurred in all three of the NK cell lines tested: however, the genes were differentially regulated in T cells. NKG2-D was expressed in nine of fourteen T-cell clones or lines in the panel, whereas NKG2-A/B was expressed in three and NKG2-C was expressed in only one. Expression of each of the transcripts was upregulated following T-cell growth factor (TCGF)-induced activation of a cloned NK cell. The limited distribution of these proteins and their sequence similarity with known receptor molecules suggest that they may function as receptors of human NK cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222470
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  • 9
    Electronic Resource
    Electronic Resource
    Fourier transform infrared spectroscopy of aqueous dispersions of phosphatidylserine-cholesterol mixtures (1991)
    Springer
    European biophysics journal 19 (1991), S. 287-293 
    Details
    ISSN: 1432-1017
    Keywords: FTIR ; Phosphatidylserine cholesterol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract The effect of cholesterol on vibrational spectra in the non polar and in the polar region of dimyristoyl phosphatidylserine (DMPS) and of phosphatidylserine from bovine spinal cord (PS) has been investigated. The small shifts in the methylene CH stretching frequencies after taking into account the contribution of the cholesterol spectrum were interpreted as a combined effect of cholesterol on the conformation of the chains and of the lesser contributions of the cholesterol methyl groups. Cholesterol also influences the ratio of the trans (1465 cm−1) to the lower wavelength (1457 cm−1) CH2 bending bands. No significant direct effect of cholesterol on the vibration of the polar residues was discerned. The small shift of the carboxylate band observed below the phase transition is probably due to the change in the intermolecular zwitterions when the average distance between the neighboring polar groups increases due to incorporation of cholesterol molecules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00183317
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  • 10
    Electronic Resource
    Electronic Resource
    Pharmacokinetics of S(+)- and R(−)-ibuprofen in volunteers and first clinical experience of S(+)-ibuprofen in rheumatoid arthritis (1990)
    Springer
    European journal of clinical pharmacology 38 (1990), S. 493-497 
    Details
    ISSN: 1432-1041
    Keywords: ibuprofen ; rheumatoid arthritis ; enantiomer ; stereoselectivity ; pharmacokinetics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary S(+)-, R(−)- or racemic ibuprofen was administered orally to volunteers in doses of 150 mg, 300 mg and 500 mg pure S(+)-, 300 mg pure R(−)- and 600 mg racemic ibuprofen. The pharmacokinetic parameters in humans showed that S(+)-ibuprofen was not inverted to R(−)-ibuprofen, whereas R(−)-ibuprofen was inverted to S(+)-ibuprofen to a variable degree. S(+)-ibuprofen and R(−)-ibuprofen given alone more rapidly reached significantly higher maximal plasma concentrations than after the same doses of the racemic compound. The elimination half-lives and clearance values for all three forms of ibuprofen were comparable. The mean residence time of S(+)-ibuprofen after R(−)- and racemic ibuprofen was significantly longer than after administration of the pure S(+)-enantiomer. Judged by the AUC, the bioavailability of S(+)-ibuprofen was independent of the dose within the range tested. Administration of S(+)-ibuprofen to 6 rheumatic patients showed that the pharmacokinetic behaviour of S(+)-ibuprofen in patients was similar to that found in volunteers. S(+)-ibuprofen proved to be an effective analgesic antirheumatic drug in the dose range 1 to 1.5 g/day.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02336690
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