[The application of cut-umbilical cord milking in term cesarean deliveries for preventing anemia and iron deficiency of newborns].

Objective: To anlysis the efficacy and safety of cut-umbilical cord milking (C-UCM) compared with immediate cord clamping in preventing anemia and iron deficiency among term cesarean-delivered newborns. Methods: A total of 485 pregnant women planning to deliver by cesarean section were recruited in this randomized controlled trial in Hunan Maternal and Child Health Hospital and Liuyang Maternal and Child Health Care Hospital from July 2016 to April 2019. A block randomization was conducted to evenly allocate them to the controlled group and the C-UCM group. In the controlled group, the cord was clamped within 30 seconds as routine. In the C-UCM group, the cord was first clamped at 25 cm from the newborn's navel, and then the blood in the cord was gently squeezed into the newborn's body until the cord became white and shriveled. The cord was clamped twice at 2-3 cm from the newborn's navel subsequently. Neonatal jaundice, hyperbilirubinemia and polycythemia were monitored before discharge. After the newborns discharged, their hemoglobin, red blood cell count, hematocrit (at the age of 1, 6 and 12 months) and serum ferritin (at the age of 6 and 12 months) were followed up; body length and weight were measured; and information about their feeding and iron supplementation were collected (at the age of 1, 6, 12 and 18 months). The two groups were compared by t test, Mann-Whitney U test, χ² test, or Fisher exact probability method. The hospital was set as a random item, and the mixed effects regression model was used to evaluate the effect of C-UCM on relevant indicators of cesarean-delivered newborns. Results: There were 244 women in the C-UCM group with an average age of (31.9±4.4) years, and 241 in the control group with an average age of (31.8±4.2) years (P>0.05). There was no statistically significant difference between the C-UCM group and the control group at 1, 6 and 12 months of age in hemoglobin [(123.6±14.5) vs (122.2±14.5) g/L, (115.3±9.4) vs (114.1±8.5) g/L, (115.6±9.6) vs (116.1±12.6) g/L] or anemia incidence rate [15.2% (17/112) vs 18.4% (19/103), 22.7% (34/150) vs 26.8% (44/164), 22.3% (25/112) vs 19.5% (22/113)] (all P>0.05). There was no statistically significant difference between the two groups at 6 and 12 months of age in serum ferritin [M (Q1, Q3), 39.9 (24.9, 61.8) vs 43.6 (25.2, 100.9) µg/L, 40.3 (25.4, 259.2) vs 40.3 (26.4, 167.6) µg/L)] or iron deficiency incidence rate [6.1% (5/82) vs 4.2% (3/72), 6.7% (5/75) vs 3.8% (3/80)] (all P>0.05). There were also no significant difference between the two groups in other indicators, such as the Z-score of weight-for-length, the incidence of neonatal jaundice, and the incidence of neonatal hyperbilirubinemia (all P>0.05). After adjusting for the relevant covariates, there were still no significant effects of C-UCM on these outcomes above. Conclusions: Compared to immediate cord clamping, the intervention of gently squeezing 25 cm of the cord does not significantly reduce the risk of anemia or iron deficiency in term cesarean-delivered newborns, nor does it have a significant impact on infant growth and development. Yet this intervention does not increase the risk of jaundice or hyperbilirubinemia in newborns as well.

Electric properties of the twelve-fold vortex structure in hexagonal manganites.

Hexagonal manganites, as a functional ferroelectric (FE) material, receive considerable attention due to their improper ferroelectricity and topological vortex structures. This family exhibits three low-symmetry states accompanied by distinct vortex domain structures. In addition to the FEP63cmand anti-FE (AFE)P-3c1 states accompanied by dual six-fold vortex structures, there is another FEP3c1 state accompanied by a twelve-fold vortex structure. The responses of FE materials to external stimuli, such as external electric fields, are the core ingredients in the physics of FEs and are significant for technological applications. Under external electric fields, the responses of FE materials are determined by special FE domain structures. The electric properties of the FEP63cmand AFEP-3c1 states are very different. However, the electric properties of the FEP3c1 state, which only stabilizes in Ga-substituted In(Mn, Ga)O3, are unclear. The present work studies the electric properties of the FEP3c1 state. The electric-field-driven transition of the FEP3c1 state is found to follow two sequences, i.e. (1) twelve-foldP3c1 → nine-foldP3c1 +P63cm→ three-foldP63cm, and (2) twelve-foldP3c1 → six-foldP3c1 → three-foldP63cm. The variation of average polarization withEfor the FEP3c1 state with the second transition sequence manifests as an unusual triple-hysteresis loop, different from the usual single-hysteresis loop of FE materials. The results are related to the coexistence of the FE and non-FE domain walls in the FEP3c1 state. Furthermore, it is found that the FEP3c1 state at substitution concentration 0.39 exhibits the highest dielectric response. The results advance our understanding of topological vortex structures in hexagonal manganites.

[Mediating effect of hypertension on risk of stroke associated with hyperuricemia].

Objective: To investigate the association between hyperuricemia and the risk for stroke occurrence, as well as the mediating effect of hypertension on this association. Methods: In this study, the China Chronic Diseases and Nutrition Surveillance system in 2015 was used as baseline data. We identified hospital admissions for stroke using the electronic homepage of inpatient medical records from 2013-2020, and death data were obtained from the 2015-2020 National Mortality Surveillance System. A retrospective cohort was established after matching and linking the database. The Cox proportional hazard regression model was used to analyze the relationship between hyperuricemia and the risk of stroke and its subtypes. Restricted cubic spline analysis was conducted to examine the dose-response relationship between serum uric acid levels and the risk for stroke. Mediation analysis was performed to investigate the mediating effect of hypertension on the association between hyperuricemia and the risk for stroke and its subtypes. Subgroup analyses were conducted based on gender and age groups. Results: A total of 124 352 study subjects were included, with an accumulative follow-up time of 612 911.36 person-years. During the follow-up period, 4 638 cases of stroke were found, including 3 919 cases of ischemic stroke and 689 cases of hemorrhagic stroke. The incidence density of stroke was 756.72 per 100 000 person-years, 641.37 per 100 000 person-years for ischemic stroke, and 114.60 per 100 000 person-years for hemorrhagic stroke. Multivariable Cox proportional hazards regression models showed that after adjusting for covariates, compared to those without hyperuricemia, individuals with hyperuricemia had a 16% higher risk for stroke [hazard ratio (HR)=1.16, 95%CI: 1.06-1.27], a 12% higher risk of ischemic stroke (HR=1.12, 95%CI: 1.01-1.24), and a 39% higher risk of hemorrhagic stroke (HR=1.39, 95%CI: 1.11-1.75). Mediation analysis showed that hypertension partially mediated the associations between hyperuricemia and the risk for stroke, ischemic stroke, and hemorrhagic stroke, with mediation proportions of 36.07%, 39.98%, and 25.34%, respectively. The mediating effect is pronounced in the male population and individuals below 65. Conclusion: Hyperuricemia is a risk factor for stroke, and hypertension partially mediates the effect of hyperuricemia on stroke.