Sonographic Predictors of Antepartum Bleeding in Placenta Previa.

OBJECTIVE: To evaluate the association between sonographic features of placenta previa and vaginal bleeding (VB). STUDY DESIGN: Retrospective cohort study of women with placenta previa identified on ultrasound between 160/7 and 276/7 weeks gestation. Placental distance past the cervical os (DPO), placental thickness, edge angle, and cervical length (CL) were measured. The primary outcome was any VB and the secondary outcome was VB requiring delivery. Median values of the sonographic features were compared for each of the outcomes using the Mann-Whitney U test. Receiver operating characteristic curves were used to compare the predictive value of sonographic variables markers and to determine optimal cut points for each measurement. Logistic regression was used to estimate the association between each measure and the outcomes while controlling for confounders. RESULTS: Of 149 women with placenta previa, 37% had VB and 15% had VB requiring delivery. Women with VB requiring delivery had significantly more episodes of VB than those who did not require delivery for VB (1.5, interquartile range [IQR] [1-3] vs 1.0 [1-5]; p = 0.001). In univariate analysis, women with VB had decreased CL (3.9 vs. 4.2 cm; p < 0.01) compared with those without. Women with VB requiring delivery had increased DPO (2.6 cm IQR [1.7-3.3] vs. 1.5 cm [1.1-2.4], p = 0.01) compared with those without. After adjusting for confounders, only CL < 4 cm remained independently associated with increased risk of VB (adjusted odds ratio: 2.27, 95% confidence interval [1.12-4.58], p = 0.01). None of the measures were predictive of either outcome (area under the curve < 0.65). CONCLUSION: Decreased CL may be associated with risk of VB in placenta previa. KEY POINTS: · Placenta previa is associated with VB.. · Sonographic markers of placenta previa are associated with VB.. · CL is associated with VB in placenta previa, whereas placental DPO is associated with higher rates of bleeding leading to delivery..

Disruption of pollen tube homogalacturonan synthesis relieves pollen tube penetration defects in the Arabidopsis O-FUCOSYLTRANSFERASE1 mutant.

During angiosperm sexual reproduction, pollen tubes must penetrate through multiple cell types in the pistil to mediate successful fertilization. Although this process is highly choreographed and requires complex chemical and mechanical signaling to guide the pollen tube to its destination, aspects of our understanding of pollen tube penetration through the pistil are incomplete. Our previous work demonstrated that disruption of the Arabidopsis thaliana O-FUCOSYLTRANSFERASE1 (OFT1) gene resulted in decreased pollen tube penetration through the stigma-style interface. Here, we demonstrate that second site mutations of Arabidopsis GALACTURONOSYLTRANSFERASE 14 (GAUT14) effectively suppress the phenotype of oft1 mutants, partially restoring silique length, seed set, pollen transmission, and pollen tube penetration deficiencies in navigating the female reproductive tract. These results suggest that disruption of pectic homogalacturonan (HG) synthesis can alleviate the penetrative defects associated with the oft1 mutant and may implicate pectic HG deposition in the process of pollen tube penetration through the stigma-style interface in Arabidopsis. These results also support a model in which OFT1 function directly or indirectly modifies structural features associated with the cell wall, with the loss of oft1 leading to an imbalance in the wall composition that can be compensated for by a reduction in pectic HG deposition.

Carbonate weathering, phosphate fertilizer, and hydrologic controls on dissolved uranium in rivers in the US Corn Belt: Disentangling seasonal geogenic- and fertilizer-derived sources.

Soil and bedrock weathering and phosphate (P) fertilizers may both contribute to the uranium (U) load of rivers in agricultural regions, but controls over their relative influence are not well known. This study investigates the U sources to rivers in Ohio, United States, part of the Eastern Corn Belt in the Mississippi River watershed. We present a regional picture of seasonal U sources to rivers based on four analyses: 1) a spatial analysis of legacy soil and water data, 2) new measurements of U and carbonate weathering products from rivers at 50 locations across the state collected seasonally over two years, 3) a weekly time series with additional 234U/238U (n = 5) and 87Sr/86Sr (n = 5) measurements from an agricultural river, and 4) a mass-balance approach to U addition to the landscape based on reported P fertilizer use. Uranium concentrations in surface waters collected statewide ranged 0.1-21 nM (n = 132), with significantly higher concentrations in the glaciated agricultural portion of the state (mean = 7.3 nM; n = 105) than the non-glaciated portion (mean = 2.0 nM; n = 24). Concentrations in the glaciated region were highest during the spring and summer and decreased during baseflow. In the time-series, concentrations were ~7 nM during baseflow and ~14 nM during intermediate seasonal discharge conditions, indicating a second more surficial endmember source of U in addition to bedrock weathering that is well correlated with other carbonate weathering products. Systematic increases in 87Sr/86Sr and decreases in 234U/238U with increasing discharge confirm a changing source of carbonate and U weathering and a third surficial endmember during high discharge events. Our mass balance approach and geochemical analysis suggest that elevated U concentrations are the result of carbonate weathering deep in the soil column during elevated seasonal flow. Further work on U dynamics in agricultural rivers is required to understand mechanism controlling seasonal changes in U concentrations and 234U/238U in downstream rivers and U flux.

Short single-frequency self-pulsing Brillouin-Raman distributed feedback fiber laser.

We demonstrate that the stimulated Brillouin scattering of a 250 mm long distributed feedback Raman fiber laser can self-pulse with repetition rates up to 7 MHz, pulse widths of 25 ns, and peak powers of 1.2 W. While both CW and pulsed lasing are produced from a bespoke grating at 1119 nm this laser design could be constructed at almost any wavelength, as the Raman and Brillouin gain regions are relative to the pump wavelength. The laser has a low lasing threshold for a Raman laser of 0.55 W, a peak slope efficiency of 14 %, and a maximum average output of 0.25 W. An investigation of beating between pure Raman and Raman-pumped Brillouin lasing shows that the outputs of the two processes are highly correlated and thus the Brillouin lasing is essentially single-frequency when CW and near transform limited for pulsed operation. A phenomenological model of the Raman-Brillouin interaction shows that the pulsing behaviour of such a cavity is expected and produces very similar pulsing to that the seen in experimental results.

The role of statins in the prevention of preeclampsia.

Preeclampsia is a common hypertensive disorder of pregnancy associated with considerable neonatal and maternal morbidities and mortalities. However, the exact cause of preeclampsia remains unknown; it is generally accepted that abnormal placentation resulting in the release of soluble antiangiogenic factors, coupled with increased oxidative stress and inflammation, leads to systemic endothelial dysfunction and the clinical manifestations of the disease. Statins have been found to correct similar pathophysiological pathways that underlie the development of preeclampsia. Pravastatin, specifically, has been reported in various preclinical and clinical studies to reverse the pregnancy-specific angiogenic imbalance associated with preeclampsia, to restore global endothelial health, and to prevent oxidative and inflammatory injury. Human studies have found a favorable safety profile for pravastatin, and more recent evidence does not support the previous teratogenic concerns surrounding statins in pregnancy. With reassuring and positive findings from pilot studies and strong biological plausibility, statins should be investigated in large clinical randomized-controlled trials for the prevention of preeclampsia.

Evaluation of classification methods for identifying multiwalled carbon nanotubes collected on mixed cellulose ester filter media.

Enhanced darkfield microscopy (EDFM) and hyperspectral imaging (HSI) are being evaluated as a potential rapid screening modality to reduce the time-to-knowledge for direct visualisation and analysis of filter media used to sample nanoparticulate from work environments, as compared to the current analytical gold standard of transmission electron microscopy (TEM). Here, we compare accuracy, specificity, and sensitivity of several hyperspectral classification models and data preprocessing techniques to determine how to most effectively identify multiwalled carbon nanotubes (MWCNTs) in hyperspectral images. Several classification schemes were identified that are capable of classifying pixels as MWCNT(+) or MWCNT(-) in hyperspectral images with specificity and sensitivity over 99% on the test dataset. Functional principal component analysis (FPCA) was identified as an appropriate data preprocessing technique, testing optimally when coupled with a quadratic discriminant analysis (QDA) model with forward stepwise variable selection and with a support vector machines (SVM) model. The success of these methods suggests that EDFM-HSI may be reliably employed to assess filter media exposed to MWCNTs. Future work will evaluate the ability of EDFM-HSI to quantify MWCNTs collected on filter media using this classification algorithm framework using the best-performing model identified here - quadratic discriminant analysis with forward stepwise selection on functional principal component data - on an expanded sample set.

The Importance of Clinical Presentation in Risk and Management of Recurrent Preterm Birth.

OBJECTIVE: This study aimed to compare the risk of recurrent spontaneous preterm birth (sPTB), as well as cerclage efficacy, between groups stratified by phenotype of the index sPTB. STUDY DESIGN: This is a retrospective cohort study of women with a history of sPTB. Included were women with a history of singleton sPTB who received progesterone in a subsequent pregnancy. Multifetal gestations and abdominal cerclage were excluded. Exposure groups were based upon the presenting symptom that preceded their first sPTB and included painless cervical dilation (PCD), preterm premature rupture of membranes (PPROM), and painful dilation (preterm labor [PTL]). Primary outcome was delivery <34 weeks in a subsequent pregnancy. Secondary outcomes included delivery <28 and <37 weeks. Rates were compared using the Chi-square test. Multivariable Poisson regression was used to adjust for confounders. RESULTS: A total of 723 women were included. A total of 114 (16%) presented with PCD, 305 (42%) with PPROM, and 304 (42%) with PTL in their first sPTB. Cerclage in subsequent pregnancy was highest in the PCD group (42%) when compared with the PPROM (16%) and PTL (12%) groups. Rates of sPTB <34 and 37 weeks were similar among the groups. After adjusting for confounders, PCD was found to significantly increase the risk of recurrent sPTB <28 weeks (incidence rate ratio: 3.46 [1.09-11.0]; p = 0.04). Of the 121 women who underwent cerclage, there were no significant differences in rates of sPTB between the clinical presentation groups. CONCLUSION: PCD as a specific phenotype of sPTB impacts recurrence of delivery before 28 weeks, but not at later gestational ages. In contrast, there was no significant association between clinical presentation of index sPTB and gestational latency in women who also underwent cerclage placement in a subsequent pregnancy. Our data suggest that clinical presentation is important with regards to recurrence of early sPTB, but not sPTB at later gestational ages. KEY POINTS: · Phenotype is critical to understanding PTB.. · Phenotype is associated with recurrent PTB.. · Painless dilation is associated with recurrent PTB..

Thermodynamic Surface Analyses to Inform Biofilm Resistance.

Biofilms are the habitat of 95% of bacteria successfully protecting bacteria from many antibiotics. However, inhibiting biofilm formation is difficult in that it is a complex system involving the physical and chemical interaction of both substrate and bacteria. Focusing on the substrate surface and potential interactions with bacteria, we examined both physical and chemical properties of substrates coated with a series of phenyl acrylate monomer derivatives. Atomic force microscopy (AFM) showed smooth surfaces often approximating surgical grade steel. Induced biofilm growth of five separate bacteria on copolymer samples comprising varying concentrations of phenyl acrylate monomer derivatives evidenced differing degrees of biofilm resistance via optical microscopy. Using goniometric surface analyses, the van Oss-Chaudhury-Good equation was solved linear algebraically to determine the surface energy profile of each polymerized phenyl acrylate monomer derivative, two bacteria, and collagen. Based on the microscopy and surface energy profiles, a thermodynamic explanation for biofilm resistance is posited.

Effect of Fasting on Total Bile Acid Levels in Pregnancy.

OBJECTIVE: To evaluate differences between fasting and nonfasting bile acid levels in asymptomatic and symptomatic pregnant women. METHODS: This is a report of two prospective cohort studies describing bile acid levels in the fasting and nonfasting state in pregnancy. The first cohort included asymptomatic women with singleton pregnancies. Women with a diagnosis of cholestasis, symptoms of cholestasis, or intolerance to components of a standardized meal were excluded. Bile acid levels were measured during the second and third trimesters after fasting and again 2 hours after a standardized meal. The second cohort included symptomatic women with singleton pregnancies in whom fasting and nonfasting bile acid levels were measured at the time of symptom evaluation. A cutoff of 10 micromoles/L was used for diagnosis. RESULTS: A total of 27 women were included in the asymptomatic cohort. Median [interquartile range] fasting bile acid levels were significantly lower than nonfasting levels in both the second trimester (4.65 micromoles/L [1.02-29.57] vs 13.62 micromoles/L [2.03-40.26]; P<.001) and third trimester (8.31 micromoles/L [1.14-51.26] vs 17.35 micromoles/L [1.77-62.93]; P<.001). Bile acid levels exceeded 10 micromoles/L in 21% of the fasting samples and in 58% of the nonfasting samples in the third trimester. A total of 26 women were included in the symptomatic cohort. Median [interquartile range] fasting bile acid levels were significantly lower than nonfasting values (11.5 micromoles/L [7-56] vs 13.5 micromoles/L [9-142]; P<.001). Six patients in the symptomatic cohort (23%) had nonfasting bile acid levels greater than 10 micromoles/L that dropped below 10 micromoles/L when fasting. CONCLUSION: Fasting bile acid levels are significantly lower when compared with nonfasting values in both asymptomatic and symptomatic pregnant women. In asymptomatic women, nonfasting bile acid levels often exceeded 10 micromoles/L whereas fasting values did not. In symptomatic women, fasting bile acid levels resulted in 23% fewer diagnoses of cholestasis when compared with nonfasting values. These findings suggest that fasting evaluation of bile acid levels or a higher threshold for diagnosis of cholestasis should be considered.

Highly-chirped Bragg gratings for integrated silica spectrometers.

A blazed chirped Bragg grating in a planar silica waveguide device was used to create an integrated diffractive element for a spectrometer. The grating diffracts light from a waveguide and creates a wavelength dependent focus in a manner similar to a bulk diffraction grating spectrometer. An external imaging system is used to analyse the light, later device iterations plan to integrate detectors to make a fully integrated spectrometer. Devices were fabricated with grating period chirp rates in excess of 100 nm mm-1, achieving a focal length of 5.5 mm. Correction of coma aberrations resulted in a device with a footprint of 20 mm×10 mm, a peak FWHM resolution of 1.8 nm, a typical FWHM resolution of 2.6 nm and operating with a 160 nm bandwidth centered at 1550 nm.

Individual inscription of spectrally multiplexed Bragg gratings in optical multicore fibers using small spot direct UV writing.

We have demonstrated the inscription of Bragg gratings into five individual cores of a seven core fiber using small spot direct UV writing. With this technique, we defined spectrally multiplexed Bragg gratings consecutively in separate cores as well as spectrally multiplexed gratings at the same longitudinal location in different cores. The effect of bending on the optical spectrum was evaluated to allow the differentiation between cross-exposure and cross-talk, and an alignment process to reduce cross-exposure by 13 dB was found.

Physical controls and ENSO event influence on weathering in the Panama Canal Watershed.

Recent empirical studies have documented the importance of tropical mountainous rivers on global silicate weathering and suspended sediment transport. Such field studies are typically based on limited temporal data, leaving uncertainty in the strength of observed relationships with controlling parameters over the long term. A deficiency of long-term data also prevents determination of the impact that multi-year or decadal climate patterns, such as the El Niño Southern Oscillation (ENSO), might have on weathering fluxes. Here we analyze an 18-year hydrochemical dataset for eight sub-basins of the Panama Canal Watershed of high-temporal frequency collected between 1998 and 2015 to address these knowledge gaps. We identified a strongly positive covariance of both cation (Ca2+, Mg2+, K+, Na+) and suspended sediment yields with precipitation and extent of forest cover, whereas we observed negative relationships with temperature and mosaic landcover. We also confirmed a statistical relationship between seasonality, ENSO, and river discharge, with significantly higher values occurring during La Niña events. These findings emphasize the importance that long-term datasets have on identifying short-term influences on chemical and physical weathering rates, especially, in ENSO-influenced regions.

Internally Controlled Methods to Quantify Pollen Tube Growth and Penetration Defects in Arabidopsis thaliana.

Double-fertilization in angiosperms requires precise communication between the male gametophyte (pollen), the female tissues, and the associated female gametophyte (embryo sac) to facilitate efficient fertilization. Numerous small molecules, proteins, and peptides have been shown to impact double-fertilization through the disruption of pollen germination, pollen tube growth, pollen tube guidance, or pollen tube penetration of the female tissues. The genetic basis of signaling events that lead to successful double-fertilization has been greatly facilitated by studies in the model organism Arabidopsis thaliana, which possesses a relatively simple reproductive physiology and a widely available T-DNA mutant seed collection. In this chapter, we detail methods for determining the effects of single gene loss-of-function mutations on pollen behavior through the creation of an internally controlled fluorescent hemizygous complement line. By transforming a single copy of the disrupted gene back into the homozygous mutant background, a precise endogenous control is generated due to the fact that pollen containing equal ratios of mutant and complemented pollen can be collected from a single flower. Using this experimental design, we describe multiple assays that can be performed in series to assess mutant pollen defects in germination, pollen tube elongation rate, and pistil penetration, which can be easily quantified alongside a "near-wildtype" complemented counterpart.

Exclusion of Pregnant Women from Clinical Trials during the Coronavirus Disease 2019 Pandemic: A Review of International Registries.

OBJECTIVE: Pregnant women have been historically excluded from clinical trials for nonobstetric conditions, even during prior epidemics. The objective of this review is to describe the current state of research for pregnant women during the coronavirus disease 2019 (COVID-19) pandemic. STUDY DESIGN: We conducted a search of international trial registries for trials relating to the novel coronavirus. The eligibility criteria for each trial were reviewed for inclusion/exclusion of pregnant women. Relevant data were extracted and descriptive statistics were calculated for individual and combined data. The total number of trials from each registry were compared, as well as the proportions of pregnancy-related trials within each. RESULTS: Among 621,370 trials in the World Health Organization International Clinical Trials Registry, 927 (0.15%) were COVID-19 related. Of those, the majority (52%) explicitly excluded pregnancy or failed to address pregnancy at all (46%) and only 16 (1.7%) were pregnancy specific. When categorized by region, 688 (74.2%) of COVID-19 trials were in Asia, followed by 128 (13.8%) in Europe, and 66 (7.2%) in North America. Of the COVID-19 trials which included pregnant women, only three were randomized-controlled drug trials. CONCLUSION: Approximately 1.7% of current COVID-19 research is pregnancy related and the majority of trials either explicitly exclude or fail to address pregnancy. Only three interventional trials worldwide involved pregnant women. The knowledge gap concerning the safety and efficacy of interventions for COVID-19 created by the exclusion of pregnant women may ultimately harm them. While "ethical" concerns about fetal exposure are often cited, it is in fact unethical to habitually exclude pregnant women from research. KEY POINTS: · Pregnancy was excluded from past pandemic research.. · Pregnancy is being excluded from COVID-19 research.. · Exclusion of pregnant women is potentially harmful..

Risk of cerebral palsy by gestational age among pregnancies at-risk for preterm birth.

Objective: Our objective was to describe cerebral palsy (CP) incidence stratified by gestational age (GA) groups within a group at risk for spontaneous preterm birth (sPTB).Study design: This is a secondary analysis of a large study of magnesium for neuroprotection. Nonanomalous, singleton gestations complicated by preterm premature rupture of membranes (PPROM) or preterm labor (PTL) were included. Infants that developed CP were compared to controls that did not. The incidence of CP was stratified by GA groups. A logistic regression model was fit to adjust for confounders.Results: Of 1747 included pregnancies, 75 (4.3%) were affected by CP. Increasing GA at delivery was associated with lower rates of CP (RR 0.96, 95% CI 0.95-0.97; p<.0001). The most significant risk factor for CP was neonatal sepsis while the most significant protective factors were magnesium and antibiotic exposure. In the adjusted analysis, magnesium exposure (aRR 0.52, 95% CI 0.33-0.84; p = .007) and antibiotic exposure (aRR 0.52, 95% CI 0.28-0.95; p = .034) remained protective.Conclusion: The risk of CP among populations at high risk for sPTB decreases with advancing GA. While the majority of cases of CP occurred in children born <34 weeks, residual risk persisted thereafter. The effect of magnesium exposure is most pronounced before 28 weeks.

Intrahepatic Cholestasis of Pregnancy.

Intrahepatic cholestasis of pregnancy is a common disorder of pregnancy manifested by pruritus and elevated bile acids. The etiology of cholestasis is poorly understood and management is difficult due to the paucity of data regarding its diagnosis, treatment, and related adverse outcomes. In this article, we review the epidemiology, pathophysiology, risk factors, laboratory findings, complications, treatment, management, and current evidence surrounding intrahepatic cholestasis of pregnancy.

Integrated polarizer based on 45° tilted gratings.

We report the first integrated implementation of a polarizer based on the use of 45° tilted gratings in planar waveguides. The waveguides and gratings are fabricated by direct UV writing in a hydrogenated germanium-doped silica-on-silicon chip. We experimentally demonstrate a polarization extinction ratio per unit length of 0.25 dB mm -1 with a modelled wavelength dependence smaller than 0.3 dB for a 20 mm device over the C band from 1530-1570 nm. We also present a novel numerical study and analytical description of the architecture that are in good agreement with each other and the experimental data.

Interspecies Bombolitins Exhibit Structural Diversity upon Membrane Binding, Leading to Cell Specificity.

Bombolitins, a class of peptides produced by bees of the genus Bombus, target and disrupt cellular membranes, leading to lysis. Antimicrobial peptides exhibit various mechanisms of action resulting from the interplay between peptide structure, lipid composition, and cellular target membrane selectivity. Herein, two bombolitins displaying significant amino-acid-sequence similarity, BII and BL6, were assessed for antimicrobial activity as well as correlated dodecylphosphocholine (DPC) micelle binding and membrane-induced peptide conformational changes. Infrared and circular dichroism spectroscopies were used to assess the structure-function relationship of each bombolitin, and the results indicate that BII forms a rigid and helically ordered secondary structure upon binding to DPC micelles, whereas BL6 largely lacks secondary structural order. Moreover, the binding affinity of each peptide to DPC micelles was determined, revealing that BL6 displayed a difference in binding affinity by over two orders of magnitude. Further investigations into the growth-inhibitory activity of the two bombolitins were performed against Escherichia coli and Saccharomyces cerevisiae. Interestingly, BII specifically targeted S. cerevisiae, whereas BL6 more effectively inhibited E. coli growth. Overall, the antimicrobial selectivity and specificity of BII and BL6 are largely dependent on the primary as well as secondary structural content of the peptides and the membrane composition.