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23 个结果
  • 简介:我们证明为四元数海森堡组上的sublaplacian的限制操作员从Lp被围住到Lp如果1p$\tfrac{4}{3}$\tfrac{4}{3}。这与海森堡组,限制操作员没从Lp在上被围住到Lp不同除非p=1。

  • 标签: HEISENBERG群 限制定理 四元 运营商 有界
  • 简介:<正>Inthispaper,weinvestigatethegeneralizedSublaplacian.Wegivetheexpressionoftherestrictionoperatorsexplicitly.Byintroducingthegeneralizedλ-twistedconvolutions,weobtaintheestimatesoftherestrictionoperatorsinthemixedL~Pspaces.Finally,wegetarestrictiontheoremassociatedwiththegeneralizedSublaplacian.

  • 标签: GENERALIZED Sublaplacian RESTRICTION THEOREM GENERALIZED CONVOLUTION
  • 简介:AbstractFetal growth restriction (FGR) has a prevalence of about 10% worldwide and is associated with an increased risk of perinatal mortality and morbidity. FGR is commonly caused by placental insufficiency and can begin early (<32 weeks) or in late (≥32 weeks) gestational age. A false positive antenatal diagnosis may lead to unnecessary monitoring and interventions, as well as cause maternal anxiety. Whereas a false negative diagnosis exposes the fetus to an increased risk of stillbirth and renders the pregnancy ineligible from the appropriate care and potential treatments. The clinical management of FGR pregnancies faces a complex challenge of deciding on the optimal timing of delivery as currently the main solution is to deliver the baby early, but iatrogenic preterm delivery of infants is associated with adverse short-and long-term outcomes. Early and accurate diagnosis of FGR could aid in better stratification of clinical management, and the development and implementation of treatment options, ultimately benefiting clinical care and potentially improving both short-and long-term health outcomes. The aim of this review is to present the new insights on biomarkers of placenta insufficiency, including their current and potential value of biomarkers in the prediction and prevention for FGR, and highlight the association between biomarkers and adverse outcomes in utero to explore the specific mechanism of impaired fetal growth that establish the basis for disease later in life.

  • 标签: Biomarkers Fetal growth restriction Placental insufficiency Adverse outcome
  • 简介:AbstractFetal growth restriction (FGR) is associated with multiple adverse perinatal outcomes, such as increased risk of intrauterine death, neonatal morbidity and mortality, and long-term adverse outcomes. Genetic etiological factors are critical in fetuses with intrauterine growth restriction, including chromosomal abnormalities, copy number variants, single gene disorders, uniparental disomy, epigenetic changes, and confined placental mosaicism. This paper aims to provide an overview of genetic defects related to FGR and to highlight the importance of prenatal genetic counseling and testing for precise diagnosis and management of FGR.

  • 标签: Genetics Fetal growth restriction Etiology
  • 简介:AbstractFetal growth restriction (FGR) is the condition in which a fetus does not reach its intrinsic growth potential and in which the shortterm and long-term risks of severe complications are increased. FGR is a frequent complication of pregnancy with a complex etiology and limited management options, other than timely delivery. The most common pathophysiological mechanism is placental insufficiency, due to many underlying causes such as maternal vascular malperfusion, fetal vascular malperfusion and villitis.Identifying truly growth restricted fetuses remains challenging. To date, FGR is often defined by a cut-off of the estimated fetal weight below a certain percentile on a population-based standard. However, small fetal size as a single marker does not discriminate adequately between fetuses or newborns that are constitutionally small but healthy and fetuses or newborns that are growth restricted and thus at risk for adverse outcomes. In 2016, the consensus definition of FGR was internationally accepted to better pinpoint the FGR population.In this review we will discuss the contemporary diagnosis and management issues. Different diagnostic markers are considered, like Doppler measurements, estimated fetal growth, interval growth, fetal movements, biomarkers, and placental markers.

  • 标签: Fetal growth restriction Growth restriction in the newborn Placental insufficiency syndrome Doppler measurements Biomarkers Placental function
  • 简介:Theaimofthispaperistogiveasimpleproofoftherestrictiontheoremforthemaximaloperatorsonthed-dimensionalEuclideanspaceRd,whosetheoremwasprovedbyCarro-Rodriguezin2012.Moreover,weshallgivesomeremarksoftherestrictiontheoremforthelinearandthemultilinearoperatorsbyCarro-RodriguezandRodriguez,too.

  • 标签: 限制定理 极大算子 多线性算子 简单证明 欧氏空间 德里
  • 简介:LetAandCdenoterealn×nmatrices.Givenrealn-vectorsx1,………,xm,m≤n,andasetofnumbers(L)={λ1,λ2…λm},Wedescrbe(Ⅰ)theset()ofallrealn×nbisymmetricpositiveseidefinitematricesAsuchthatAxiisthe"best"approximatetoλixi,i=1,2,...,minFrobeniusnormand(Ⅱ)theYinset()whichminimizeFrobeniusnormof||C-Y||.AnexistencetheoremofthesolutionsforProblemⅠandProblemⅡisgivenandthegeneralexpressionofsolutionsforProblemⅠisderived.SomesufficientconditionsunderwhichProblemⅠandProblemⅡhaveanexplicitsolutionisprovided.Anumer-icalalgorithmofthesolutionforProblemⅡhasbeenpresented.

  • 标签: 双对称半正定矩阵 特征值 矩阵范数 数值计算 光谱限制
  • 简介:AbstractSelective fetal growth restriction (sFGR) is a severe condition that complicates 10% to 15% of all monochorionic diamniotic (MCDA) twin pregnancies. Pregnancies complicated with sFGR are at high risk of intrauterine demise or adverse perinatal outcome for the twins. Three clinical types have been described according to the umbilical artery (UA) Doppler pattern observed in the smaller twin: type I, when the UA Doppler is normal; type II, when there is persistent absent or reversed end-diastolic blood flow in the UA Doppler; and type III, when there is intermittent absent and/or reversed end-diastolic blood flow in the UA Doppler. Clinical evolution and management options mainly depend on the type of sFGR. Type I is usually associated with a good prognosis and is managed conservatively. There is no consensus on the management of types II and III, but in earlier and more severe presentations, fetal interventions such as selective laser photocoagulation of placental anastomoses or selective fetal cord occlusion of the smaller twin may be considered. This review aims to provide updated information about the diagnosis, evaluation, follow-up, and management of sFGR in MCDA twin pregnancies.

  • 标签: Twins Monochorionic diamniotic twins Selective fetal growth restriction Birthweight discordance Fetal therapy Placenta
  • 简介:这篇文章在生长曲线模型题目为回归系数考虑线性评估者的考虑到不完全的椭圆体的限制。为分别地,在同类、非同类的线性评估者的班上可被考虑的线性评估者的必要、足够的条件在二次的损失功能下面被获得。他们是在文学的一些存在结果的归纳。

  • 标签: 生长曲线方程式 线性估计值 数学模型 椭圆
  • 简介:AbstractFetal growth restriction (FGR) is a common complication of pregnancy associated with higher rates of perinatal mortality and morbidity, as well as a variety of long-term adverse outcomes. To standardize the clinical practice for the management of FGR in China, Fetal Medicine Subgroup, Chinese Society of Perinatal Medicine, Chinese Medical Association and Maternal-Fetal Medicine Committee, Chinese Society of Obstetrics and Gynecology,Chinese Medical Association organized an expert committee to provide official consensus-based recommendations on FGR. We evaluated the evidence provided by relevant high-quality literature, performed a three-round Delphi study and organized face-to-face meetings with experts from multidisciplinary backgrounds. The consensus includes the definition, prenatal screening, prevention, diagnosis, monitoring and management of FGR.

  • 标签: Delphi technique Fetal growth restriction Practice guideline
  • 作者: Luming Sun Dick Oepkes
  • 学科: 医药卫生 >
  • 创建时间:2022-12-13
  • 出处:《母胎医学杂志(英文)》 2022年第03期
  • 机构:Shanghai Key Laboratory of Maternal Fetal Medicine, Department of Fetal Medicine & Prenatal Diagnosis Center, Shanghai First Maternity and Infant Hospital, School of Medicine, Tongji University, Shanghai 201204, China,Division of Fetal Medicine, Department of Obstetrics, Leiden University Medical Ce
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  • 简介:瞄准:调查17β-estradiol(E2)的效果,Peganum伤害翼摘录(PHE)和各种各样的睾丸参数上的热量的限制(CR)在老化期间。方法:Twelve-month-old雄的老鼠与E2或PHE被对待6个月,或提交了到CR(40%)。结果:我们的结果证明雌激素和CR能由象aromatase和雌激素受体基因表情的减少一样阻止睾丸激素和E2层次的减少保护男性腺。确实,E2,PHE和CR处理在超级氧化物dismutase活动导致了增加并且减少阴囊的酶的活动:gamma-glutamyltransferase,碱的磷酸酶,喂奶deshydrogenase以及aspartate并且喂奶在年老的动物的transaminases。另外,阴囊的过氧化氢酶和gluthationeperoxidase活动在18月年龄与未经治疗的动物相比在E2,PHE和对待CR的老鼠被提高。而且,estradiol,PHE和CR的积极效果被类脂化合物的底层进一步每氧化支持。精子发生的恢复在对待的老鼠被记录。结论:除为精子发生有益的一本低热量的食谱以外,雌激素的一个保护的antioxydant角色被建议。雌激素推迟阴囊的房间损坏,它导致功能的老朽并且,因此雌激素在保护繁殖功能免受在年老的睾丸在大数量生产的反应的氧种类(ROS)施加的不利效果的伤害是有用的。

  • 标签: 雌激素类 17Β-雌二醇 睾丸 抗氧化剂
  • 简介:AbstractObjective:To assess the clinical features of fetal growth restriction (FGR) in women with hypertensive disorders of pregnancy in China.Methods:This is a retrospective cohort study. The clinical data of 4 451 women with hypertensive disorders of pregnancy were retrospectively collected from 11 tertiary hospitals across ten provinces in China during January 2015 to December 2015. The mean maternal age was (31.0±5.4) years old. Participants were divided into FGR group (n= 670) and non-FGR group (n= 3 781). The incidence and clinical features of FGR, and its correlation with gestational age, previous FGR history, 24-hour urinary protein excretion, and hemolysis, elevated liver enzyme and low platelet count (HELLP) syndrome were analyzed. Student’s t-test and Chi-square test were used when comparing clinical features between FGR and non-FGR groups.Results:The overall incidence of FGR was 15.1% (670/4 451). The FGR incidence was 22.4% (433/1 937) in women with severe preeclampsia and 18.6% (68/365) in women with chronic hypertension with superimposed preeclampsia, respectively. FGR was more prevalent in women who had preterm births than those who had term births (22.8% (432/1 898) vs. 9.3% (238/2 553), P < 0.001). It was also more prevalent in women with early-onset preeclampsia than those with late-onset preeclampsia (18.4% (189/1 025) vs. 14.0% (481/3 426), P= 0.001). Women with a previous FGR history had a significantly higher FGR incidence than those without an FGR history (66.7% (4/6) vs. 15.7% (250/1 596), P= 0.007). The presence of abnormal results of the umbilical artery Doppler (13% (87/670) vs. 2.4% (89/3 781), P < 0.001) and the middle cerebral artery Doppler (3.3% (22/670) vs. 0.4% (15/3 781), P < 0.001) was higher in the FGR group compared with the non-FGR group, while the presence of increased uterine artery resistance was not statistically different (1.5% (10/670) vs. 0.8% (29/3 781), P= 0.072). The FGR group delivered earlier than the non-FGR group ((35.3±3.0) weeks vs. (36.4±4.3) weeks, P < 0.001) with lower birth weight (1 731.0±574.5) g vs. (2 753.9±902.1) g, P < 0.001, higher fetal or neonatal death (9.4% (63/670) vs. 4.2% (157/3 781), P < 0.001), and higher cesarean section rate (82.5% (553/670) vs. 70.2% (2 656/3 781), P < 0.001). In the FGR group, more neonates had 5-minute Apgar score ≤7 (7.9% (53/670) vs. 3.9% (149/3 780), P < 0.001), with higher neonatal intensive care unit admission rate (48.1 % (322/670) vs. 23.3% (881/3 781), P < 0.001). More cases of HELLP syndrome occurred in the FGR group (6.9% (46/670) vs. 3.2% (122/3 781), P < 0.001). Women with FGR had heavier 24-hour urinary protein excretion than those without FGR ((3.9±3.7) g vs. (3.1±4.2) g, P= 0.005).Conclusion:In pregnancies with hypertensive disorders, increased risks of FGR are associated with preterm birth, birth before 34 weeks, and a previous FGR history. FGR is related to higher occurrence of abnormal uterine artery Doppler and umbilical artery Doppler. When hypertensive disorders is complicated by FGR, there appears to be higher maternal morbidity including higher rate of HELLP syndrome, cesarean section, and heavier proteinuria, as well as worse neonatal outcomes.

  • 标签: China Fetal growth restriction Hypertension Pregnancy-induced Pre-eclampsia Incidence