A Multicenter, Retrospective Comparison Study of Pregnancy Outcomes According to Placental Location in Placenta Previa.

Background: We investigated the association between placental location and pregnancy outcomes in placenta previa. Methods: This multi-center retrospective study enrolled 781 women who delivered between May 1999 and February 2020. We divided the dataset into anterior (n = 209) and posterior (n = 572) groups and compared the baseline characteristics and obstetric and neonatal outcomes. The adverse obstetric outcomes associated with placenta location were evaluated using a multivariate logistic analysis. Results: Gestational age at delivery in the anterior group (253.0 ± 21.6) was significantly lower than that in the posterior group (257.6 ± 19.1) (p = 0.008). The anterior group showed significantly higher parity, rates of previous cesarean section, non-vertex fetal positions, admissions for bleeding, emergency cesarean sections, transfusions, estimated blood loss, and combined placenta accrete spectrum (p < 0.05). In the multivariate analysis, the anterior group had higher rates of transfusion (OR 2.23; 95% CI 1.50-3.30), placenta accreta spectrum (OR 2.16; 95% CI 1.21-3.97), and non-vertex fetal positions (OR 2.47; 95% CI 1.09-5.88). Conclusions: These findings suggest that more caution is required in the treatment of patients with anterior placenta previa. Therefore, if placenta previa is diagnosed prenatally, it is important to determine the location of the body and prepare for massive bleeding in the anterior group.

A multicenter, retrospective comparison of pregnancy outcomes between groups of preterm labor nulliparous mothers treated with atosiban vs. ritodrine in singleton and multiple pregnancies.

OBJECTIVE: To evaluate the safety and efficacy of atosiban and ritodrine in pregnant women who were hospitalized for threatened preterm labor (TPL). MATERIALS AND METHODS: Diagnosis records of preterm labor and subsequent pregnancy-related records and medical records of newborns were extracted from the Clinical Data Warehouse of the Catholic Medical Center's affiliated hospital. Since 2009, cases of preterm labor diagnosed before 34 weeks of pregnancy for first-time mothers who delivered at any one of three hospitals and who received drug treatment for more than 2 days to delay delivery were included in the dataset. Based on characteristics of Korea's national health insurance system, the drug treatment after diagnosis of preterm labor could be classified into cases using only ritodrine (571 women), cases using only atosiban (244 women), and cases where ritodrine treatment was started and then changed to atosiban (275 women). Demographic factors, obstetric outcomes, neonatal outcomes of the two groups were analyzed. RESULTS: The duration and maintenance of pregnancy were found to be similar between the two groups, although the initial cervical length was significantly shorter in the atosiban cohort (AC). Only in multifetal pregnancies, the maintenance of pregnancy was significantly longer in the AC. The total duration of pregnancy did not show any significant difference between the two groups regardless of singleton or multiple pregnancy. However, the distribution graph showed non-responders in the ritodrine cohort (RC). Our study showed a difference in neonatal birth weight of singleton between the two groups. The length of hospitalization and the NICU admission rate were also significantly higher in the RC for singleton. Although not significant, the proportion of numbers with an Apgar score less than 7 was higher in the RC. Neonatal death was more common in the RG (8 cases in AC and 18 cases in RC). CONCLUSIONS: Using atosiban for TPL is more effective than using ritodrine for maintaining pregnancy in the case of a multifetal pregnancy. In singleton pregnancies, neonatal outcomes of the atosiban group were superior to those of the ritodrine group. There seems to be a non-responder group when using ritodrine for TPL. Further studies are needed to determine causes of non-responders of ritodrine and effects of ritodrine on the fetus.

COVID-19 Vaccine Acceptance during Pregnancy and Influencing Factors in South Korea.

Pregnant women were excluded from vaccination against Coronavirus 2019 (COVID-19) until September 2021 in South Korea. Although vaccination for pregnant women started in October 2021, vaccine acceptance in pregnant women is yet unknown. This cross-sectional study aimed to investigate COVID-19 vaccine acceptance during pregnancy and influencing factors. An anonymous survey was distributed in obstetrics departments to all pregnant or postpartum women, during the prenatal or postpartum visit. The proportion of self-reported COVID-19 vaccination during pregnancy among 436 women was 26.6%. Pregnancy-related independent factors influencing maternal COVID-19 vaccination were "received vaccine information about from obstetrics and gynecology (OBGYN) doctors" (OR 3.41, 95% CI 2.05-5.65), "cohabitant COVID-19 vaccination" (OR 2.43, 95% CI 1.06-5.59), and "second trimester" (OR 7.35, 95% CI 1.54-35.15). In women who did not want to get vaccinated, the most common reason for COVID-19 vaccination hesitancy was concern that COVID-19 vaccine might affect the fetus (91.7%, 243/266), followed by distrust in COVID-19 vaccine effectiveness (42.6%, 113/266). This study showed that providing information about maternal COVID-19 vaccination, especially by OBGYN doctors, is crucial for increasing vaccination coverage in pregnant women. Providing updated evidence of COVID-19 vaccine efficacy and safety in pregnant women may be also helpful for increasing vaccine acceptance.

The effect of tocolytics in women with preterm labor after 34 weeks of gestation: A propensity score-matched study.

OBJECTIVES: Since late preterm neonates are physiologically less mature than term neonates, the use of antenatal corticosteroids in the late preterm period has been recommended. The use of tocolytics can also be considered to gain valuable time for using antenatal corticosteroids in the late preterm period. In this study, we examined the efficacy of tocolytics on prolonging pregnancy in the late preterm period, by comparing women who received tocolytics with those who received none. STUDY DESIGN: This retrospective cohort study included women who were admitted due to preterm labor after 34 weeks of gestation and delivered in the late preterm period. Primary outcome was time from admission to delivery (days). Secondary outcomes were the proportion of preterm births within 2 days, and within 7 days, completed cycles of antenatal corticosteroids, and the neonatal outcomes. Primary and secondary outcomes were compared according to the use of tocolytics. Propensity score matching was performed to create comparable groups. The maternal age, pre-pregnancy body mass index, nulliparity, history of preterm birth, hypertensive disease during pregnancy, gestational diabetes mellitus, history of preterm labor, gestational age at admission, cervical length, and the number of contractions were the baseline characteristics included in the propensity score. RESULTS: Of 275 women, 44 women received tocolytics (tocolytics group) and 231 women did not (no tocolytics group). We matched 44 women who received tocolytics and 44 women who didn't. The tocolytics group was shown to exhibit a longer time from admission to delivery than the no tocolytics group, with a hazard ratio for tocolytics of 0.4 (95 % confidence interval, 0.2-0.6). In addition, the proportion of preterm births occurring within 2 days and 7 days were lower in those receiving tocolytics compared to those that didn't. CONCLUSION: In this propensity score matched-study, the use of tocolytics had a significant effect on pregnancy prolongation, which allows more time for use of corticosteroids in women with preterm labor after 34 weeks of gestation.

The trend in cesarean myomectomies and the risk of obstetrical complications in Korea.

BACKGROUND: To evaluate pregnancy outcomes and the risk of adverse obstetrical outcomes of cesarean myomectomy (CM) compared with cesarean section (CS) only, and to investigate the trend of surgeons in choosing CM. METHODS: A retrospective cohort study was performed on all patients who underwent CS complicated by leiomyoma at two university hospitals between January 2010 and May 2020. All patients were categorized into the CM (341 women) or CS-only (438 women) group. We analyzed the demographic factors, obstetric factors, surgical outcomes, and possible risk factors for adverse outcomes between the two groups. RESULTS: Women who underwent CS only were significantly more likely to have a previous myomectomy and multiple leiomyoma history than women who underwent CM. The gestational age at delivery and pregnancy complications were significantly higher in the CS-only group. The mean size of the leiomyomas was larger in the CM group than in the CS-only group (5.8 ± 3.2 cm vs. 5.2 ± 3.1 cm, P = 0.005). The operation time and history of previous CS and preterm labor were higher in the CM group. The leiomyoma types differed between the two groups. The subserosal type was the most common in the CM group (48.7%), and the intramural type was the most common in the CS-only group. Patients in the CM group had fewer than three leiomyomas than those in the CS-only group. Preterm labor and abnormal presentation were relatively higher in the CM group than in the CS-only group, concerning leiomyoma presence. There were no significant differences in the preoperative and postoperative hemoglobin levels. The size of the leiomyoma (odds ratio [OR] = 1.162; 95% confidence interval [CI]: 1.07-1.25; P < 0.001) and operation time > 60 min (OR = 2.461; 95% CI: 1.45-4.15) were significant independent predictors of adverse outcomes after CM. CONCLUSIONS: CM should be considered a reliable and safe approach to prevent the need for another surgery for remnant leiomyoma. Herein, surgeons performed CM when uterine leiomyomas were large, of the subserosal type, or few. Standardized treatment guidelines for myomectomy during CSs in pregnant women with uterine fibroids should be established.

Fetal Doppler to predict cesarean delivery for non-reassuring fetal status in the severe small-for-gestational-age fetuses of late preterm and term.

OBJECTIVE: To evaluate the significance of fetal Doppler parameters in predicting adverse neonatal outcomes and the risk of cesarean delivery due to non-reassuring fetal status, in severe small for gestational age (SGA) fetuses of late preterm and term gestation. METHODS: Fetal brain and umbilical artery (UmA) Doppler parameters of cerebroplacental ratio (CPR) and UmA pulsatility index (PI) were evaluated in a cohort of 184 SGA fetuses between 34 and 41 weeks gestational age, who were less than the 5th percentile. The risks of neonatal morbidities and cesarean delivery due to non-reassuring fetal status were analyzed. RESULTS: Univariate analysis revealed that abnormal CPR was significantly associated with cesarean delivery due to non-reassuring fetal status (P=0.018), but not with neonatal morbidities. However, abnormal CPR did not increase the risk of cesarean delivery due to non-reassuring fetal status in multivariate logistic regression analysis. Abnormal CPR with abnormal PI of UmA was associated with low Apgar score at 1 minute (P=0.048), mechanical ventilation (P=0.013) and cesarean delivery due to non-reassuring fetal status (P<0.001), in univariate analysis. It increased risk of cesarean delivery for non-reassuring fetal status (adjusted odds ratio, 7.0; 95% confidence interval, 1.2-41.3; P=0.033), but did not increase risk of low Apgar score or mechanical ventilation in multivariate logistic regression analysis. CONCLUSION: Abnormal CPR with abnormal PI of UmA increases the risk of cesarean delivery for non-reassuring fetal status, in severe SGA fetuses of late preterm and term. Monitoring of CPR and PI of UmA can help guide management including maternal hospitalization and fetal monitoring.

Ammonia-oxidizers' diversity in wastewater treatment processes.

The diversity of ammonia-oxidizing bacteria (AOB) within the beta-subclass of Proteobacteria was investigated by genus- and family-specific real-time quantitative PCR (qPCR) assays on samples drawn from wastewater treatment systems. The 16S rRNA gene copy numbers ranged from 7.0 × 103 to 6.8 × 106, 1.1 × 107 to 1.8 × 107, and 2.9 × 105 to 1.5 × 107 copies/mL, respectively. Volumetric ammonium load (VAL) in the wastewater treatment systems calculated using the AOB numbers was in the range of 2.1-12.6 mM/d. Distribution patterns of eutrophic (i.e. Nitrosomonas europaea and Nitrosomonas nitrosa clusters) and oligotrophic (i.e. Nitrosomonas cryotolerans cluster) AOB groups were correlated with the VAL values. A high possibility of potential false-positive detection by family-specific qPCR assays was established by evaluating theoretical specificity in in silico and experimental investigations. The specificities of genus-specific qPCR assays were confirmed by amoA PCR, followed by cloning and sequencing. VAL must be the factor influencing the inclusion of AOB species. However, there was no significant correlation between the volatile suspended solid concentration representing chemical oxygen demand and N. europaea's community population, indicating that the degree of ammonia oxidation influenced the community cluster of Nitrosomonas relatively more.

Carbon material distribution and flux analysis under varying glucose concentrations in hydrogen-producing Clostridium tyrobutyricum JM1.

Anaerobic glucose metabolism in hydrogen-producing Clostridium tyrobutyricum was investigated in batch culture with varying initial glucose concentrations (27.8-333.6mM). To understand the regulation of metabolism, the carbon material and reduction balances were applied to estimate the carbon flux distribution for the first time, and metabolic flux analysis (MFA) was used to provide qualitative information and guidance for effective metabolic design. The overall flux distribution suggested that C. tyrobutyricum metabolism has a high capacity for the production of butyrate and hydrogen at an initial glucose concentration of 222.4mM, with balanced activities of NADH and ATP.

Systematic strategy for designing immidazolium containing precursors to produce N-heterocyclic carbenes: a DFT study.

A series of cationic N-heterocyclic carbene (NHC) precursors that can be utilized as fluorescent chemosensors for carbon dioxide capture were investigated by density functional theory (DFT) calculations. Activation energy barriers for the reactions of the cationic NHC precursors and hydrogen carbonate (HCO3(-)) based on intrinsic reaction coordinate (IRC) profiles as well as proton affinity of the precursors were compared. The calculated proton affinity of 1-ethyl-3-methylimidazol-2-yliene was in good agreement with experimental one within the margin of error. We clarified main factors to lower the activation energy barrier based on the correlation among the number of N-heterocyclic functional group, aromatic ring size, and structural characteristics for the candidate compounds. On the basis of the results, it was verified that some of our model systems spontaneously generate NHCs without any specific catalyst.

Effect of initial glucose concentrations on carbon material and energy balances in hydrogen-producing Clostridium tyrobutyricum JM1.

The carbon metabolism of newly isolated Clostridium tyrobutyricum JM1 was investigated at varying initial glucose concentrations (27.8-333.6mM). Because an understanding of metabolic regulations was required to provide guidance for further effective metabolic design or optimization, in this case, maximizing hydrogen production, carbon material, and energy balances by C. tyrobutyricum JM1 were determined and applied in anaerobic glucose metabolism. The overall carbon distribution suggested that initial glucose concentrations had strong influence on the stoichiometric coefficients of products and the molar production of ATP on the formation of biomass. C. tyrobutyricum JM1 had a high capacity for hydrogen production at the initial glucose concentration of 222.4 mM with high concentrations of acetate and butyrate.

The effects of pH on carbon material and energy balances in hydrogen-producing Clostridium tyrobutyricum JM1.

The effects of pH on hydrogen fermentation of glucose by newly isolated H(2)-producing bacterium Clostridium tyrobutyricum JM1 were investigated in batch cultivations. The changes of carbon material and energy balances by pH conditions provided useful information for understanding and interpreting the regulatory system of the microorganism, and for optimization of a desired product, in this case, molecular hydrogen. The most probable metabolic pathways of C. tyrobutyricum JM1 were determined through an accurate analysis of stoichiometry and the consistency of the experimental data, checked by high carbon recovery. The carbon material and energy balances were adequately applied to estimate the carbon-flow distribution. They suggested that pH 6.3 was appropriate to maximize hydrogen production with a high concentration of butyrate and balanced activities of NADH.

Biological hydrogen production by immobilized cells of Clostridium tyrobutyricum JM1 isolated from a food waste treatment process.

A fermentative hydrogen-producing bacterium, Clostridium tyrobutyricum JM1, was isolated from a food waste treating process using 16S rRNA gene sequencing and amplified ribosomal DNA restriction analysis (ARDRA). A fixed-bed bioreactor packed with polyurethane foam as support matrix for the growth of the isolate was operated at different hydraulic retention time (HRT) to evaluate its performance for hydrogen production. The reactor achieved the maximal hydrogen production rate of 7.2 l H(2)l(-1)d(-1) at 2h HRT, where hydrogen content in biogas was 50.0%, and substrate conversion efficiency was 97.4%. The maximum hydrogen yield was 223 ml (g-hexose)(-1) with an influent glucose concentration of 5 g l(-1). Therefore, the immobilized reactor using C. tyrobutyricum JM1 was an effective and stable system for continuous hydrogen production.

Optimization of key process variables for enhanced hydrogen production by Enterobacter aerogenes using statistical methods.

The individual and mutual effects of glucose concentration, temperature and pH on the hydrogen production by Enterobacter aerogenes were investigated in a batch system. A Box-Behnken design and response surface methodology (RSM) were employed to determine the optimum condition for enhanced hydrogen production. The hydrogen production rate was investigated by simultaneously changing the three independent variables, which all had significant influences on the hydrogen production rate. The maximum hydrogen production rate of 425.8 ml H(2)(g dry cell h)(-1) was obtained under the optimum condition of glucose concentration 118.06 mM, temperature 38 degrees C and pH 6.13. The experimental results showed that the RSM with the Box-Behnken design was a useful tool for achieving high rate of hydrogen production by E. aerogenes.

Process stability and microbial community structure in anaerobic hydrogen-producing microflora from food waste containing kimchi.

Hydrogen production by the dark fermentation of food wastes is an economic and environmentally friendly technology to produce the clean energy source as well as to treat the problematic wastes. However, the long-term operations of the continuous anaerobic reactor for fermentative hydrogen production were frequently unstable. In this study, the structure of microbial community within the anaerobic reactor during unstable hydrogen production was examined by denaturing gradient gel electrophoresis (DGGE) and terminal restriction fragment length polymorphism (T-RFLP) techniques. The changes in microbial community from H(2)-producing Clostridium spp. to lactic acid-producing Lactobacillus spp. were well coincident with the unexpected process failures and the changes of metabolites concentrations in the effluent of the anaerobic reactor. As the rate of hydrogen production decreased, effluent lactic acid concentration increased. Low rate of hydrogen production and changes in microbial community were related to the 'kimchi' content and storage temperature of food waste feed solution. After low temperature control of the storage tank of the feed solution, any significant change in microbial community within the anaerobic reactor did not occur and the hydrogen production was very stably maintained for a long time.

Modeling and optimization of photosynthetic hydrogen gas production by green alga Chlamydomonas reinhardtii in sulfur-deprived circumstance.

Biological hydrogen production by the green alga Chlamydomonas reinhardtii under sulfur-deprived conditions has attracted great interest due to the fundamental and practical importance of the process. The photosynthetic hydrogen production rate is dependent on various factors such as strain type, nutrient composition, temperature, pH, and light intensity. In this study, physicochemical factors affecting biological hydrogen production by C. reinhardtii were evaluated with response surface methodology (RSM). First, the maximum specific growth rate of the alga associated with simultaneous changes of ammonium, phosphate, and sulfate concentrations in the culture medium were investigated. The optimum conditions were determined as NH(4+) 8.00 mM, PO(4)(3-) 1.11 mM, and SO(4)(2-) 0.79 mM in Tris-acetate-phosphate (TAP) medium. The maximum specific growth rate with the optimum nutrient concentrations was 0.0373 h(-1). Then, the hydrogen production rate of C. reinhardtii under sulfur-deprivation conditions was investigated by simultaneously changing two nutrient concentrations and pH in the medium. The maximum hydrogen production was 2.152 mL of H(2) for a 10-mL culture of alga with density of 6 x 10(6) cells mL(-1) for 96 h under conditions of NH(4)(+) 9.20 mM, PO(4)(3-) 2.09 mM, and pH 7.00. The obtained hydrogen production rate was approximately 1.55 times higher than that with the typical TAP medium under sulfur deficiency.

Mechanism of hexavalent chromium removal by dead fungal biomass of Aspergillus niger.

When synthetic wastewater containing Cr(VI) was placed in contact with the dead fungal biomass of Aspergillus niger, the Cr(VI) was completely removed from aqueous solution, whereas Cr(III), which was not initially present, appeared in aqueous solution. Desorption and X-ray photoelectron spectroscopy (XPS) studies showed that most of the Cr bound on the biomass was in trivalent form. These results indicated that the main mechanism of Cr(VI) removal was a redox reaction between Cr(VI) and the dead fungal biomass, which is quite different from previously reported mechanisms. The influences of contact time, pH, Cr(VI) concentration, biomass concentration and temperature on Cr(VI) removal were also evaluated. The Cr(VI) removal rate increased with a decrease in pH and with increases in Cr(VI) concentration, biomass concentration and temperature. Although removal kinetics was dependent on the experimental conditions, Cr(VI) was completely removed in the aqueous solution. In conclusion, a new mechanism of Cr(VI) removal by the dead fungal biomass has been proposed. From a practical viewpoint, this abundant and inexpensive dead fungal biomass has potential application in the conversion of toxic Cr(VI) into less toxic or nontoxic Cr(III).