The impact of non-pharmaceutical interventions on premature births during the COVID-19 pandemic: a nationwide observational study in Korea

BackgroundNon-pharmaceutical interventions (NPIs), such as social distancing and hand washing, have been associated with a decline in the preterm birth rate worldwide. We aimed to evaluate whether the preterm birth rate in Korea during the coronavirus disease 2019 lockdown has changed compared to that in previous years.MethodA birth registry from the Korea Statistical Information Service, which is a nationwide official database, was used to include all births claimed to have occurred between 2011 and 2020. Newborns with gestational age (GA) less than 22 weeks and birth weight less than 220 g were excluded. The pre-NPI period was designated as January 2011 to January 2020, and the NPI period was defined as February 2020 to December 2020. We assessed the effect of NPI on the incidence of prematurity per 100 births using an interrupted time-series quasi-experimental design and implementing an autoregressive integrated moving average (ARIMA) model.ResultsFrom 2011 to 2020, a total of 3,931,974 live births were registered, among which 11,416 were excluded. Consequently, the final study population included 3,920,558 live births (both singleton and multiple births) among which 275,009 (7.0%) were preterm. The preterm birth rate was significantly higher during the NPI period (8.68%) compared to that in the pre-NPI period (6.92%) (P < 0.001). The ARIMA model showed that in all singleton and multiple births, except those in July (observed 9.24, expected 8.54, [95% prediction interval {PI} 8.13–8.96], percent difference 7.81%), September (observed 7.89, expected 8.35, [95% PI 7.93–8.76], percent difference −5.66%), and December (observed 9.90, expected 9.40, [95% PI 8.98–9.82], percent difference 5.2%), most observed values were within the 95% PI of the expected values and showed an increasing trend.ConclusionIn this nationwide observational study, the trend in premature birth rate did not significantly change due to NPI implementation in Korea, as it had been increasing since 2011. The trend of Korea's birth rate appears to be unaffected by the implementation of NPIs; however, further studies with a longer follow-up period are needed

Research for the Optimal Flux-Cored Arc Welding Process of 9% Nickel Steel Using Multi Object Optimization with Solidification Crack Susceptibility

The environment of the global shipbuilding market is changing rapidly. Recently, the International Maritime Organization (IMO) has tightened regulations on sulfur oxide content standards for marine fuels and tightened sulfur oxide emission standards for the entire coastal region of China to consider the environment globally and use LNG as a fuel. There is a tendency for the number of vessels to operate to increase significantly. To use cryogenic LNG fuel, various pieces of equipment, such as storage tanks or valves, are required, and equipment using steel, which has excellent impact toughness in cryogenic environments, is required. Four steel types are specified in the IGG Code, and 9% Ni steel is mostly used for LNG fuel equipment. However, to secure safety at cryogenic temperatures, a systematic study investigating the causes of quality deterioration occurring in the 9% Ni steel welding process is required and a discrimination function capable of quality evaluation is urgent. Therefore, this study proposes a plan where the uniform quality of 9% Nickel steel is secured by reviewing the tendency of the solidification crack susceptibility among the quality problems of cryogenic steel to establish the criteria for quality deterioration and to develop a system capable of quality discrimination and defect avoidance

Fog Deposition and Accumulation on Smooth and Textured Hydrophobic Surfaces

We investigated the deposition and accumulation of droplets on both smooth substrates and substrates textured with square pillars, which were tens of micrometers in size. After being coated with a hydrophobic monolayer, substrates were placed in an air flow with a sedimenting suspension of micrometer-sized water droplets (i.e., fog). We imaged the accumulation of water and measured the evolution of the mean drop size. On smooth substrates, the deposition process was qualitatively similar to condensation, but differences in length scale revealed a transient regime not reported in condensation experiments. Based on previous simulation results, we defined a time-scale characterizing the transition to steady-state behavior. On textured substrates, square pillars promoted spatial ordering of accumulated drops. Furthermore, texture regulated drop growth: first enhancing coalescence when the mean drop size was smaller than the pillar, and then inhibiting coalescence when drops were comparable to the pillar size. This inhibition led to a monodisperse drop regime, in which drop sizes varied by less than 5%. When these monodisperse drops grew sufficiently large, they coalesced and could either remain suspended on pillars (i.e., Cassie–Baxter state) or wet the substrate (i.e., Wenzel state)

Growth and developmental outcomes of infants with hypoxic ischemic encephalopathy

Abstract Despite advances in obstetric care, hypoxic ischemic encephalopathy (HIE) remains a significant disease burden. We determined the national trends of HIE prevalence, therapeutic hypothermia (TH) use, mortality, and outcomes from 2012 to 2019. This study included term infants diagnosed with HIE between 2012 and 2019 from the National Health Insurance Service database. The prevalence of HIE was 2.4 per 1000 births without significant change during the period. TH was performed in approximately 6.7% of infants with HIE, and the annual variation ranged from 2.4 to 12.5%. The mortality among all term infants with HIE was 4.6%. The mortality rate among infants with HIE and TH significantly declined from 40 to 16.9% during the eight years. Infants with TH had higher mortality, increased use of inhaled nitric oxide, and more invasive ventilator use, indicating greater disease severity in the TH group. Infants with TH also showed significantly poorer outcomes, including delayed development, cerebral palsy, sensorineural hearing loss, and seizure, compared to infants without TH (p < 0.0001). With the increasing application of TH, mortality and developmental outcomes among infants with HIE have been improving in the past eight years in Korea. Further efforts to improve outcomes should be needed

Factors associated with the response to postnatal dexamethasone use in very low birthweight infants: a nationwide cohort study

Background Dexamethasone is widely used as a systemic corticosteroid to treat and prevent bronchopulmonary dysplasia (BPD) in preterm infants. We evaluated the current epidemiology of dexamethasone use to prevent BPD and analyse the factors associated with the response to dexamethasone in very low birthweight infants using a nationwide database.Methods We included very low birthweight infants born between January 2013 and December 2020 with a gestational age of 23–31 weeks using data from the Korean Neonatal Network registry. Patients were grouped based on their dexamethasone use into ‘Dex’ or ‘No Dex’ groups. Clinical variables and data were collected, and the annual trends of dexamethasone use and the proportion of patients who received dexamethasone according to gestational age were analysed. Respiratory outcomes were compared between the groups. Univariate and multivariate analyses were performed to analyse factors associated with the response to dexamethasone in BPD.Results Of 11 261 eligible infants, 2313 (20.5%) received dexamethasone, and 1714 (74.1%) of them were diagnosed with moderate-to-severe BPD. The 8-year annual prevalence of dexamethasone use was 17.7–22.3%. The ‘Dex’ group had more moderate-to-severe BPD, more frequent invasive ventilation use at a postmenstrual age of 36 weeks and longer ventilator duration. Birth weight, 5-minute APGAR score, pulmonary hypertension within the first 28 days, surgical treatment of patent ductus arteriosus, medical treatment of patent ductus arteriosus, pathological chorioamnionitis, hydrocortisone or budesonide use, surgical management of necrotising enterocolitis and fungal sepsis were associated with BPD after dexamethasone use.Conclusions Approximately 20.5% of preterm infants received dexamethasone, and the frequency increased as gestational age decreased. Poor response to dexamethasone was associated with antenatal and postnatal inflammation, low birth weight and early pulmonary hypertension

Electrochemical Investigations of Double Perovskite M₂NiMnO₆ (Where M = Eu, Gd, Tb) for High-Performance Oxygen Evolution Reaction

Double perovskites are known for their special structures which can be utilized as catalyst electrode materials for electrochemical water splitting to generate carbon-neutral hydrogen energy. In this work, we prepared lanthanide series metal-doped double perovskites at the M site such as M2NiMnO6 (where M = Eu, Gd, Tb) using the solid-state reaction method, and they were investigated for an oxygen evolution reaction (OER) study in an alkaline medium. It is revealed that the catalyst with a configuration of Tb2NiMnO6 has outstanding OER properties such as a low overpotential of 288 mV to achieve a current density of 10 mAcm−2, a lower Tafel slope of 38.76 mVdec−1, and a long cycling stability over 100 h of continuous operation. A-site doping causes an alteration in the oxidation or valence states of the NiMn cations, their porosity, and the oxygen vacancies. This is evidenced in terms of the Mn4+/Mn3+ ratio modifying electronic properties and the surface which facilitates the OER properties of the catalyst. This is discussed using electrochemical impedance spectroscopy (EIS) and electrochemical surface area (ECSA) of the catalysts. The proposed work is promising for the synthesis and utilization of future catalyst electrodes for high-performance electrochemical water splitting

Controlled Grafting of Colloidal Nanoparticles on Graphene through Tailored Electrostatic Interaction

Nanoparticle/graphene hybrid composites have been of great interest in various disciplines due to their unique synergistic physicochemical properties. In this study, we report a facile and generalized synthesis method for preparing nanoparticle/exfoliated graphene (EG) composites by tailored electrostatic interactions. EG was synthesized by an electrochemical method, which produced selectively oxidized graphene sheets at the edges and grain boundaries. These EG sheets were further conjugated with polyethyleneimine to provide positive charges at the edges. The primary organic ligands of the colloidal nanoparticles were exchanged with Cl- or MoS42- anions, generating negatively charged colloidal nanoparticles in polar solvents. By simple electrostatic interactions between the EG and nanoparticles in a solution, nanoparticles were controllably assembled at the edges of the EG. Furthermore, the generality of this process was verified for a wide range of nanoparticles, such as semiconductors, metals, and magnets, on the EG. As a model application, designed composites with size-controlled FeCo nanoparticle/EG were utilized as electromagnetic interference countermeasure materials that showed a size-dependent shift of the frequency ranges on the electromagnetic absorption properties. The current generalized process will offer great potential for the large-scale production of well-designed graphene nanocomposites for electronic and energy applications