The Role of Friction in Compaction and Segregation of Granular Materials

We investigate the role of friction in compaction and segregation of granular materials by combining Edwards' thermodynamic hypothesis with a simple mechanical model and mean-field based geometrical calculations. Systems of single species with large friction coefficients are found to compact less. Binary mixtures of grains differing in frictional properties are found to segregate at high compactivities, in contrary to granular mixtures differing in size, which segregate at low compactivities. A phase diagram for segregation vs. friction coefficients of the two species is generated. Finally, the characteristics of segregation are related directly to the volume fraction without the explicit use of the yet unclear notion of compactivity.Comment: 9 pages, 6 figures, submitted to Phys. Rev.

Longitudinal Trends in Pregnancy Outcomes Among Women With Inflammatory Bowel Disease in the Era of Biologics: A 20-Year Nationwide Analysis.

BACKGROUND: Many women with inflammatory bowel disease (IBD) are diagnosed by their reproductive years. Prior literature suggests that women with IBD may be at increased risk of adverse pregnancy outcomes. Biologics have revolutionized IBD treatment, and current evidence favors continuation during pregnancy. We sought to examine trends in pregnancy outcomes over 20 years with the evolution of IBD treatment. METHODS: Using the National Inpatient Sample, IBD and non-IBD obstetric hospitalizations were identified between 1998 and 2018 using International Classification of Diseases 9 and 10 codes. Outcomes of interest included cesarean delivery, gestational diabetes, preeclampsia/eclampsia, premature rupture of membranes (PROM), preterm delivery, fetal growth restriction (FGR), fetal distress, and stillbirth. Stratified by Crohns disease (CD), ulcerative colitis (UC), and non-IBD deliveries, temporal trends and multivariable logistic regression were analyzed. RESULTS: There were 48 986 CD patients, 30 998 UC patients, and 69 963,805 non-IBD patients. Between 1998 and 2018, CD deliveries increased from 3.3 to 12.9 per 10 000 deliveries (P < 0.001) and UC deliveries increased from 2.3 to 8.6 per 10 000 deliveries (P < 0.001). Cesarean deliveries, gestational diabetes, preeclampsia/eclampsia, PROM, FGR, and fetal distress increased over time for IBD and non-IBD women, while preterm deliveries decreased (P < 0.001). Multivariable analyses demonstrated that IBD patients had higher risk of cesarean delivery, preeclampsia/eclampsia, PROM, and preterm delivery compared with non-IBD patients. CONCLUSION: Over a 20-year period, live deliveries amongst women with IBD have increased. Trends in pregnancy outcomes have followed a similar trajectory in patients with and without IBD. However, there is still demonstrable risk of adverse pregnancy outcomes in patients with IBD

Comparison between the old and new MFMU TOLAC Calculator – Which is more accurate?

In 2017, the Maternal Fetal Medicine Units (MFMU) Network disseminated a Trial of Labor after Cesarean (TOLAC) calculator. An updated (2021) version of the calculator does not include race and ethnicity, but instead focuses on prior medical and OB history, in addition to age and BMI. The objective of this study was to compare the actual vs predicted VBAC rates between the old and new MFMU calculators

Prenatal Diagnosis of Fetal Aqueductal Stenosis: A Multicenter Prospective Observational Study through the North American Fetal Therapy Network.

INTRODUCTION: A critical component of an evidence-based reassessment of in-utero intervention for fetal aqueductal stenosis (fetal AS) is determining if the prenatal diagnosis can be accurately made at a gestational age amenable to in-utero intervention. METHODS: A multicenter, prospective, observational study was conducted through the North American Fetal Therapy Network (NAFTNet). Pregnancies complicated by severe central nervous system (CNS) ventriculomegaly (lateral ventricle diameter >15 mm) not secondary to a primary diagnosis (myelomeningocele, encephalocele, etc.) were recruited at diagnosis. Imaging and laboratory findings were recorded in an online REDCap database. After evaluation, investigators were asked to render their degree of confidence in the diagnosis of fetal AS. The prenatal diagnosis was compared to the postnatal diagnosis obtained through neonatal neuroimaging. Performance characteristics of ultrasound and magnetic resonance imaging (MRI) were calculated, as was the mean gestational age at diagnosis. RESULTS: Between April 2015 and October 2022, eleven NAFTNet centers contributed 64 subjects with severe fetal CNS ventriculomegaly. Of these, 56 had both prenatal and postnatal diagnoses recorded. Ultrasound revealed 32 fetal AS true positives, 4 false positives, 7 false negatives, and 13 true negatives, rendering a sensitivity of 0.82, a specificity of 0.76, a positive predictive value of 0.89, and a negative predictive value of 0.65. The mean gestational age at diagnosis by ultrasound was 25.5 weeks (std +/- 4.7 weeks). The proportion of agreement (true positive + true negative/n) was highest at 24 weeks gestation. For fetal MRI (n = 35), the sensitivity for fetal AS was 0.95, specificity was 0.69, positive predictive value was 0.84, and negative predictive value was 0.90. MRI was performed at 25 weeks on average. CONCLUSION: The prenatal diagnosis of fetal AS can be made with accuracy at a gestational age potentially amenable to in-utero intervention. Only 7% of subjects were incorrectly diagnosed prenatally with fetal AS by ultrasound and 11% by MRI. Diagnostic accuracy of fetal AS will likely improve with increased experience

Real World Clinical Experience Using Daily Intelligence-Assisted Online Adaptive Radiotherapy for Head and Neck Cancer

Background Adaptive radiation therapy (ART) offers a dynamic approach to address structural and spatial changes that occur during radiotherapy (RT) for locally advanced head and neck cancers. The integration of daily ART with Cone-Beam CT (CBCT) imaging presents a solution to enhance the therapeutic ratio by addressing inter-fractional changes. Methods We evaluated the initial clinical experience of daily ART for patients with head and neck cancer using an online adaptive platform with intelligence-assisted workflows on daily CBCT. Treatment included auto-contour and structure deformation of Organs at Risk (OARs) and target structures, with adjustments by the treating physician. Two plans were generated: one based on the initial CT simulation with the edited structures (scheduled) and a re-optimized plan (adaptive). Both plans were evaluated and the superior one approved and delivered. Clinical and dosimetric outcomes were reviewed. Results Twenty two patients with head and neck cancers (7 Nasopharynx, 6 Oropharynx, 1 oral cavity, 8 larynx) stages I-IVA were treated with daily ART. 770 adaptive and scheduled radiotherapy plans were generated. 703 (91.3%) adaptive plans were chosen. Median time to deliver ART was 20 minutes (range: 18-23). Adaptive compared to scheduled plans demonstrated improved mean V95 values for the PTV70, PTV59.5, and PTV56 by 1.2%, 7.2%, and 6.0% respectively and a mean 1.4% lower maximum dose in PTV70. Fourteen of 17 OARs demonstrated improved dosimetry with adaptation, with select OARs reaching statistical significance. At a median follow up of 14.1 months, local control was 95.5%, two patients developed metastatic disease and four patients died. 9.1% of patients had acute grade 3 dysphagia and 13.6% had grade 2 chronic xerostomia. Discussion These findings provide real world evidence of the feasibility and dosimetric benefit of incorporating daily ART on CBCT in the treatment of head and neck cancer. Prospective study is needed to determine if these dosimetric improvements translate into improved outcomes

Neonatal Survival After Serial Amnioinfusions for Bilateral Renal Agenesis: The Renal Anhydramnios Fetal Therapy Trial

IMPORTANCE: Early anhydramnios during pregnancy, resulting from fetal bilateral renal agenesis, causes lethal pulmonary hypoplasia in neonates. Restoring amniotic fluid via serial amnioinfusions may promote lung development, enabling survival. OBJECTIVE: To assess neonatal outcomes of serial amnioinfusions initiated before 26 weeks\u27 gestation to mitigate lethal pulmonary hypoplasia. DESIGN, SETTING, AND PARTICIPANTS: Prospective, nonrandomized clinical trial conducted at 9 US fetal therapy centers between December 2018 and July 2022. Outcomes are reported for 21 maternal-fetal pairs with confirmed anhydramnios due to isolated fetal bilateral renal agenesis without other identified congenital anomalies. EXPOSURE: Enrolled participants initiated ultrasound-guided percutaneous amnioinfusions of isotonic fluid before 26 weeks\u27 gestation, with frequency of infusions individualized to maintain normal amniotic fluid levels for gestational age. MAIN OUTCOMES AND MEASURES: The primary end point was postnatal infant survival to 14 days of life or longer with dialysis access placement. RESULTS: The trial was stopped early based on an interim analysis of 18 maternal-fetal pairs given concern about neonatal morbidity and mortality beyond the primary end point despite demonstration of the efficacy of the intervention. There were 17 live births (94%), with a median gestational age at delivery of 32 weeks, 4 days (IQR, 32-34 weeks). All participants delivered prior to 37 weeks\u27 gestation. The primary outcome was achieved in 14 (82%) of 17 live-born infants (95% CI, 44%-99%). Factors associated with survival to the primary outcome included a higher number of amnioinfusions (P = .01), gestational age greater than 32 weeks (P = .005), and higher birth weight (P = .03). Only 6 (35%) of the 17 neonates born alive survived to hospital discharge while receiving peritoneal dialysis at a median age of 24 weeks of life (range, 12-32 weeks). CONCLUSIONS AND RELEVANCE: Serial amnioinfusions mitigated lethal pulmonary hypoplasia but were associated with preterm delivery. The lower rate of survival to discharge highlights the additional mortality burden independent of lung function. Additional long-term data are needed to fully characterize the outcomes in surviving neonates and assess the morbidity and mortality burden

Accuracy of Sonographic Chorionicity Classification in Twin Gestations

To evaluate the accuracy of sonographic classification of chorionicity in a large cohort of twins and investigate which factors may be associated with sonographic accuracy

Monitoring and Management of Hemolytic Disease of the Fetus and Newborn Based on an International Expert Delphi Consensus

: The study aimed to develop structured, expert-based clinical guidance on the prenatal and postnatal management of hemolytic disease of the fetus and newborn. A Delphi procedure was conducted among an international panel of experts in fetal medicine, neonatology, and hematology. Experts were selected based on their expertise, relevant publications, and affiliations. The domains were (i) prenatal workup, (ii) prenatal monitoring and management, (iii) intrauterine transfusion, (iv) delivery, and (v) postnatal management. The pre-defined cut-off for consensus was ≥70% agreement. One hundred-seven experts representing 25 countries across six continents completed the first round, and 100 (93.5%) completed the subsequent rounds. 75.3% agreed on using cfDNA to determine fetal antigen status, particularly for RhD, Kell, and Rhc antigens. The critical titer, requiring fetal monitoring via ultrasound, is considered when the threshold of ≥16 is for non-Kell antigens. 70.0% agreed on the use of maternal IVIg in pregnancies with prior intrauterine transfusion (IUT) <24 weeks or fetal/neonatal death due to HDFN. The minimum GA for IUT is 16 to 18 weeks, and the maximum is 350/7 to 356/7 weeks. Postnatal management consensus was reached for the following: anemia labs should be investigated in the affected neonates before hospital discharge (92.0% agreement), and if they received IUT, the labs should be repeated within one week of discharge (84.0% agreement). 96.0% agreed that exchange transfusions should be centralized in hospitals with sufficient exposure and experience, and 92.0% agreed that the hemoglobin cut-off level to consider transfusion following hospital discharge is 7g/dL, and the newborns need to be monitored until 2-3 months of age (96.0% agreement)