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71.
Leber congenital amaurosis (LCA) is a blinding retinal disease that presents within the first year after birth. Using exome sequencing, we identified mutations in the nicotinamide adenine dinucleotide (NAD) synthase gene NMNAT1 encoding nicotinamide mononucleotide adenylyltransferase 1 in eight families with LCA, including the family in which LCA was originally linked to the LCA9 locus. Notably, all individuals with NMNAT1 mutations also have macular colobomas, which are severe degenerative entities of the central retina (fovea) devoid of tissue and photoreceptors. Functional assays of the proteins encoded by the mutant alleles identified in our study showed that the mutations reduce the enzymatic activity of NMNAT1 in NAD biosynthesis and affect protein folding. Of note, recent characterization of the slow Wallerian degeneration (Wld(s)) mouse model, in which prolonged axonal survival after injury is observed, identified NMNAT1 as a neuroprotective protein when ectopically expressed. Our findings identify a new disease mechanism underlying LCA and provide the first link between endogenous NMNAT1 dysfunction and a human nervous system disorder.  相似文献   
72.
To identify common variants influencing body mass index (BMI), we analyzed genome-wide association data from 16,876 individuals of European descent. After previously reported variants in FTO, the strongest association signal (rs17782313, P = 2.9 x 10(-6)) mapped 188 kb downstream of MC4R (melanocortin-4 receptor), mutations of which are the leading cause of monogenic severe childhood-onset obesity. We confirmed the BMI association in 60,352 adults (per-allele effect = 0.05 Z-score units; P = 2.8 x 10(-15)) and 5,988 children aged 7-11 (0.13 Z-score units; P = 1.5 x 10(-8)). In case-control analyses (n = 10,583), the odds for severe childhood obesity reached 1.30 (P = 8.0 x 10(-11)). Furthermore, we observed overtransmission of the risk allele to obese offspring in 660 families (P (pedigree disequilibrium test average; PDT-avg) = 2.4 x 10(-4)). The SNP location and patterns of phenotypic associations are consistent with effects mediated through altered MC4R function. Our findings establish that common variants near MC4R influence fat mass, weight and obesity risk at the population level and reinforce the need for large-scale data integration to identify variants influencing continuous biomedical traits.  相似文献   
73.
Constitutional abnormalities at the imprinted 11p15 growth regulatory region cause syndromes characterized by disordered growth, some of which include a risk of Wilms tumor. We explored their possible contribution to nonsyndromic Wilms tumor and identified constitutional 11p15 abnormalities in genomic lymphocyte DNA from 13 of 437 individuals (3%) with sporadic Wilms tumor without features of growth disorders, including 12% of bilateral cases (P = 0.001) and in one familial Wilms tumor pedigree. No abnormality was detected in 220 controls (P = 0.006). Abnormalities identified included H19 DMR epimutations, uniparental disomy 11p15 and H19 DMR imprinting center mutations (one microinsertion and one microdeletion), thus identifying microinsertion as a new class of imprinting center mutation. Our data identify constitutional 11p15 defects as one of the most common known causes of Wilms tumor, provide mechanistic insights into imprinting disruption and reveal clinically important epigenotype-phenotype associations. The impact on clinical management dictates that constitutional 11p15 analysis should be considered in all individuals with Wilms tumor.  相似文献   
74.
1IntroductionEnvironment-economycoordinationdevelopmentisoneofthemostconcernsatpresenttime.However,whatiscoordinationdevelopment,itsspecificationandthekindofitsmodelstructureetc.arestillunknown.Infact,coordinationdevelopmentissimplyaslogan.Thispaperrepresentsthattheultimategoalofenvironmentalprotectionandeconomicdevelopmentistomeetthedemandofpeople.Thisisdecidedbythesubjectivevalueofthenecessitiesfortotalmankinddevelopment.Mankindproducesphysicalsubstanceandundertakesenvironmentalprotection,b…  相似文献   
75.
Study on the REM Model for Group Decision Making   总被引:1,自引:0,他引:1  
IntroductionAsocialchoicefunctionisamappingwhichassignsanonemptysubsetofthepotentialfeasiblesubsettoeachorderedpairconsistentofapotentialfeasiblesubsetofalternativesandascheduleorprofileofvoters'preferences.Consideranopinionaggregationprobleminwhichagroupofexpertsgivetheirscoresthatexpresstheirpreferencestoasetofalternativesanddesiretocombinetheirscoresintoasingleaggregationpreferenceoverthealternativeset.Theunderlyingideahereisthattheconsensusofnumerousexpertsresultsinasuperiorpreferenceonthe…  相似文献   
76.
1.IntroductionWeareconcernedwithalgebraicdifferentialpolynomials(abbreviatedas'd-pcis)inafinitenumberofdifferentialindeterminatesoveradifferentialfieldofcharacteristic0.Givenafinitesetofsuchd-pcis,wewouldliketostudyd-Zero(),thedifferentialalgebraicsetdefinedbyPoverauniversaldifferentialfield.Wemayaskwhetherd-Zero()isempty,whetherad-pcivanishesond-Zero()(differentialradicalidealmembershipproblem),whatthedimensionofd-Zero()is,howtodecomposed-Zero()intoirreduciblealgebraicdifferentialsets,andso…  相似文献   
77.
1.IntroductionAnUInberofauthorshaveconsideredtheproblemoffittingmodelsofquasi-independencetocontingenCytabledatawhichareeithertriangUlarorhaveanexcludeddiagonal.hithispaperthevariousmethodsproposedforfittingthesemodelsarecompared.ItisthenshoWnthstparameterestimatesarethesamefordifferentmodelsinsomecases.Anew,verysample,easytoimplemeDtalgoritlunispreseDted.Finallysomepreviousiterstivemethodsarecomparedwiththenewmethod.2.Quasi-IndependenceModeisforContingencyamblesSupposethatatwo-waycolltin…  相似文献   
78.
1.IntroductionThecolltrolproblemofnonlinearuncertainsystemshasbeenextensivelyresearchedformanyyears.Manymethodshavebeenproposedandsomeprogresshasbeenmade.[1]poiedsoutthatsomesecondordersystemshaveaninherelltpropertythatthereexistscertainregioninwhichalltrajectoriesofthesystemremaininginitaftercertaintimeTwillconvergetotheorigin.Basedonthisproperty,anewapproachhajsbeenputforwardtoconstructacolltinuousfeedbacklawsuchthatallsystem'strajectoriesmovetowardtheregionandeventuallyremaininit.In[2,3],a…  相似文献   
79.
1.INTaODUCTIONThemultilayerfeedforwardneuralnetworks(MFNN)hasbeenwidelyappliedinmanyfieldssuchaspatternrecognition,nonlinearoptimization,systemidentificationandcontrol.Thesimpleback-propagation(BP)learningalgorithmisusuallyadoptedtoupdateitsweights.TheBPalgorithm,however,suffersdrawbacksofslowconvergenceandunpredictablesolutionsduringlearning.Althoughmailyapproachessuchasvariablestepsize,conjugategradient,pseudo-Newtonmethods[4]andothermethods[3,10],havebeendevelopedtoovercometheproble…  相似文献   
80.
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