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The behavior of a nano-scale cylindrical body (e.g., a fiber), lying on a substrate and acted upon by a combination of normal and tangential forces, is the subject of this investigation. As the scale decreases to the nano level, adhesion becomes an important issue in this contact problem. Thus, this investigation treats the two-dimensional plane strain elastic deformation of both the cylinder and the substrate during a rolling/sliding motion, including the effect of adhesion using the Maugis model. For the initiation of sliding, the Mindlin approach is used, whereas for rolling, the Carter approach is utilized. Each case is modified for nano-scale effects by including the effect of adhesion on the contact area and by using the adhesion theory of friction for the friction stress. Analytical results are given for the normal and tangential loading problems, including the initiation of sliding and rolling in terms of dimensionless quantities representing adhesion, cylinder size, and applied forces. [DOI: 10.1115/1.1831291]

Research has established a two-dimensional model to describe the fluid mechanics of air reverser air cushions in web-handling systems. The model utilizes the conservation of mass and momentum in theoretical analysis techniques for one- and two-dimensional solutions. Design considerations are discussed.

In magnetic tape recording it is important to control the tape displacement as it is transported over guides and recording heads. In this paper a numerical solution is presented for the transient motion of a tape that is circumferentially transported. The tape may be modelled as a thin cylindrical shell, with 'gyroscopic' effects arising from the tape transport. Spatial derivatives are discretized with finite difference approximations, and time derivatives are discretized by Newmark's method. The result is a robust computer algorithm that is used in making 3D-transient simulations of flexural waves following a radial load. This ability is demonstrated to be important for realizing that reflection of the waves from the lateral sides of the tape has significant effect on the transient displacement. Results that have been previously published on 'critical' speeds, wave shapes near a concentrated load point, and the dominant period of the load point displacement are further developed. A better approximation of the critical tape speed is presented, and the dominant period of the load point displacement is found to be dependent on the tape velocity.

06-1082 Zen, G., and S. Muftu. Stability of an axially accelerating string subjected to frictional guiding forces. Journal of Sound and Vibration (United Kingdom) 289(3):551-576, Jan. 24, 2006 (www.idealibrary.com). KEYWORDS: [...]

Objective: To pilot measurement of hair cortisol concentration (HCC) in pregnant women with opioid use disorder and their infants over time and study the potential utility of hair cortisol as a biomarker of chronic stress in this population., Study Design: In this pilot prospective cohort study of mother-infant dyads with and without prenatal opioid exposure, we obtained mother-infant HCCs at delivery and again within 1 to 3 months' postpartum. HCCs were compared between the opioid and control groups and between the two time points., Results: There were no significant differences between opioid and control group maternal or infant HCCs at either time point. However, within the opioid-exposed group, there was a significant increase in infant HCCs across the two time points., Conclusion: This pilot study describes our experience with the measurement of HCCs in opioid-exposed mother-infant dyads., Key Points: · Maternal stress impacts fetal and child health.. · Many stressors in pregnant women with opioid use disorder.. · Hair cortisol may be a useful stress biomarker.., Competing Interests: None declared., (Thieme. All rights reserved.)

Objective: The aim of the study is to explore the early parenting experiences among a cohort of postpartum individuals with opioid use disorder (OUD) both during and after the delivery hospitalization to identify areas of intervention to strengthen bonding and attachment., Methods: Semistructured qualitative interviews with recently pregnant people with OUD assessed parenting needs, supports, and goals in the context of the demands of addiction treatment and early motherhood. Probes explored the relationship between early parenting experiences, addiction, and recovery, as well as enabling factors and barriers to mother-infant bonding. Interviews were completed between 2019 to 2020. A constant comparative methods approach was used for codebook development and analysis., Results: Twenty-six women completed interviews a mean of 10.1 months postpartum. Twenty-four women were receiving methadone or buprenorphine treatment at delivery for OUD. Four interrelated themes emerged. Women experienced the following: (1) increased surveillance from healthcare workers who doubted their parenting ability; (2) a desire for a "normal" early parenting experience that was not disrupted by increased medical monitoring and surveillance; (3) complex and intersecting identities of being both a mother and a person in recovery; and (4) the importance of support from and advocacy by clinicians and peers to developing maternal confidence and connection., Conclusions: Interventions are needed to improve the early parenting experiences of opioid-exposed mother-infant dyads, to address the mutual mistrust between health care providers and parents, and to provide additional supports to families. Promotion of positive attachment and parental self-efficacy should be prioritized over increased surveillance and scrutiny to sustain maternal recovery trajectories into early childhood and foster family well-being., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 American Society of Addiction Medicine.)

Objectives: Some states, including Massachusetts, require automatic filing of child abuse and neglect for substance-exposed newborns, including infants exposed in-utero to clinician-prescribed medications to treat opioid use disorder (MOUD). The aim of this article is to explore effects of these mandated reporting policies on pregnant and postpartum people receiving MOUD., Methods: We used modified grounded research theory, literature findings, and constant comparative methods to extract, analyze and contextualize perinatal experiences with child protection systems (CPS) and explore the impact of the Massachusetts mandated reporting policy on healthcare experiences and OUD treatment decisions. We drew from 26 semi-structured interviews originally conducted within a parent study of perinatal MOUD use in pregnancy and the postpartum period., Results: Three themes unique to CPS reporting policies and involvement emerged. First, mothers who received MOUD during pregnancy identified mandated reporting for prenatally prescribed medication utilization as unjust and stigmatizing. Second, the stress caused by an impending CPS filing at delivery and the realities of CPS surveillance and involvement after filing were both perceived as harmful to family health and wellbeing. Finally, pregnant and postpartum individuals with OUD felt pressure to make medical decisions in a complex environment in which medical recommendations and the requirements of CPS agencies often compete., Conclusions for Practice: Uncoupling of OUD treatment decisions in the perinatal period from mandated CPS reporting at time of delivery is essential. The primary focus for families affected by OUD must shift from surveillance and stigma to evidence-based treatment and access to supportive services and resources., (© 2023. The Author(s).)

Background: The Academy of Breastfeeding Medicine (ABM) revised the 2015 version of the substance use disorder (SUD) clinical protocol to review the evidence and provide updated literature-based recommendations related to breastfeeding in the setting of substance use and SUD treatments. Key Information: Decisions around breastfeeding are an important aspect of care during the peripartum period, and there are specific benefits and risks for substance-exposed mother-infant dyads. Recommendations: This protocol provides breastfeeding recommendations in the setting of nonprescribed opioid, stimulant, sedative-hypnotic, alcohol, nicotine, and cannabis use, and SUD treatments. Additionally, we offer guidance on the utility of toxicology testing in breastfeeding recommendations. Individual programs and institutions should establish consistent breastfeeding approaches that mitigate bias, facilitate consistency, and empower mothers with SUD. For specific breastfeeding recommendations, given the complexity of breastfeeding in mothers with SUD, individualized care plans should be created in partnership with the patient and multidisciplinary team with appropriate clinical support and follow-up. In general, breastfeeding is recommended among mothers who stop nonprescribed substance use by the time of delivery, and they should continue to receive ongoing postpartum care, such as lactation support and SUD treatment. Overall, enhancing breastfeeding education regarding substance use in pregnancy and lactation is essential to allow for patient-centered guidance.

Introduction: Medications to treat opioid use disorder (MOUD) during pregnancy and in the postpartum period remain underutilized. A need exists to enhance our understanding of modifiable factors, facilitators, and barriers to MOUD utilization and adherence in the perinatal period to improve maternal and child outcomes., Methods: The study conducted semi-structured qualitative interviews with recently pregnant people with opioid use disorder (OUD) to explore experiences as a pregnant and/or parenting person with OUD, perceptions of enabling factors and barriers to treatment utilization, incentivizing factors for maintaining adherence, and acceptability of ongoing supports to sustain treatment adherence. The study team used constant comparative methods to analyze transcripts and develop the codebook. The team double coded the transcripts, with an overall kappa coefficient of 0.88., Results: The study team interviewed twenty-six women on average 10.1 months after delivery. All women had some prior experience using MOUD. Four unique themes emerged as barriers to medication utilization and adherence in the perinatal period: 1) Lack of agency and autonomy surrounding medication decisions because pregnancy or parenting status affected treatment adherence; 2) Hesitancy to use MOUD to minimize risk of newborn withdrawal; 3) Concern about increased scrutiny and potential loss of custody due to mandated child protective services reporting for opioid-exposure at delivery in Massachusetts; and 4) Perception that treatment environments, particularly methadone clinics, did not provide gender-responsive or equitable care, and standardized, inflexible visit regulations were particularly difficult to comply with in the early postpartum period., Conclusions: Women with OUD experienced a double bind when making perinatal treatment decisions, describing pressure to use MOUD with negative consequences after delivery. Key areas for possible intervention emerged from interviews. These areas include improving uptake of shared decision-making to increase patient autonomy and agency, particularly among those in the earliest stages of recovery during pregnancy; ongoing education around perinatal MOUD safety and efficacy; detangling MOUD and neonatal withdrawal signs from mandated child protective services reporting; and improving gender-responsive and equitable care in substance use disorder treatment programs, including incorporating the utilization of home visiting services for dosing assessments and administration in the early postpartum period., (Copyright © 2022 Elsevier Inc. All rights reserved.)

It has been suggested that aberrant activation of glycogen synthase kinase-3-beta (GSK-3β) can trigger abnormal tau hyperphosphorylation and aggregation, which ultimately leads to neuronal/synaptic damage and impaired cognition in Alzheimer disease (AD). We examined if isoform-selective partial reduction of GSK-3β can decrease pathological tau changes, including hyperphosphorylation, aggregation, and spreading, in mice with localized human wild-type tau (hTau) expression in the brain. We used adeno-associated viruses (AAVs) to express hTau locally in the entorhinal cortex of wild-type and GSK-3β hemi-knockout (GSK-3β-HK) mice. GSK-3β-HK mice had significantly less accumulation of hyperphosphorylated tau in synapses and showed a significant decrease of tau protein spread between neurons. In primary neuronal cultures from GSK-3β-HK mice, the aggregation of exogenous FTD-mutant tau was also significantly reduced. These results show that a partial decrease of GSK-3β significantly represses tau-initiated neurodegenerative changes in the brain, and therefore is a promising therapeutic target for AD and other tauopathies., Competing Interests: Teresa Gómez-Isla participated as speaker in an Eli Lilly and Company-sponsored educational symposium and serves in an Eli Lilly Data Monitoring Committee. All other authors declare no competing interests., (© 2021 The Authors.)

Dental implants with an internal connection have been designed to establish a better stress distribution when lateral external forces act on the prosthesis and minimize the forces transmitted to the fastening screw. In the present study, 10 externally and 10 internally hexed implants were tested with a compressive force applied with an Instron Universal machine. Four cycles of loading-unloading were applied to each specimen to achieve displacements of 0.5, 1, 2, and 2.5 mm. The mean loads for the first cycle were 256.70 N for the external connection and 256 N for the internal connection implants. The independent t test did not reveal any significant differences among the 2 tested groups (P = .780). For the second cycle, the mean loads needed for a displacement of 1 mm were 818.19 N and 780.20 N for the external connection and the internal connection implants, respectively. The independent t test revealed significant differences among the 2 tested groups (P < .001). In the third cycle, the mean load values for a 2-mm displacement were 1394.10 N and 1225.00 N. The independent t test revealed significant differences among the 2 tested groups (P < .001). The mean loads for the fourth cycle were 1488.00 N for the external connection and 1029.00 N for the internal connection implants. These loads were required for a displacement of 2.5 mm. The independent t test revealed significant differences among the 2 tested groups (P < .001). The results of this in vitro study suggest that the internal connection design of the examined implant system could not prevent screw loosening during overloading. No implant or prosthesis failure was noticed in either group.

Statement of Problem: The external contour of an implant and the magnitude of occlusal loading can have significant effects on the load transfer characteristics and may result in different bone failure rates for different implant systems., Purpose: The goal of this study was to investigate the effects of external geometry and occlusal load magnitude on bone failure modes for 5 commercially available dental implant systems., Material and Methods: Five different implant systems; Ankylos, Astra, Bicon, ITI, and Nobel Biocare, comparable in size, but different in thread profile and crest module shapes, were compared using the finite element method. Type II bone quality was approximated and complete osseous integration was assumed. Occlusal loads of varying magnitudes (0 to 2000 N) were applied on the abutments supporting single tooth restorations at 11.3 degrees from the vertical axis with a 1-mm offset. Total overloaded bone area, where tensile and compressive normal stresses fell outside of the recommended limits of 100 and 170 MPa, respectively, was investigated for different load levels., Results: For moderate levels of occlusal loads up to 300 N, the compact bone was not overloaded by any of the implant systems. At the extreme end of the occlusal load range (1000 N or more) the overloading characteristics of implants may be dependent on geometric shape., Conclusion: In general, overloading occurs near the superior region of compact bone, in compression, and it is primarily caused by the normal and lateral components of the occlusal load. At the region of intersection of compact and trabecular bone, overloading occurs in tension due to the vertical component of the occlusal load. For excessive forces greater than 1000 N, the overloaded areas of the bone varied considerably among 5 different implants systems evaluated.