Advanced materials for micro/nanorobotics.

Autonomous micro/nanorobots capable of performing programmed missions are at the forefront of next-generation micromachinery. These small robotic systems are predominantly constructed using functional components sourced from micro- and nanoscale materials; therefore, combining them with various advanced materials represents a pivotal direction toward achieving a higher level of intelligence and multifunctionality. This review provides a comprehensive overview of advanced materials for innovative micro/nanorobotics, focusing on the five families of materials that have witnessed the most rapid advancements over the last decade: two-dimensional materials, metal-organic frameworks, semiconductors, polymers, and biological cells. Their unique physicochemical, mechanical, optical, and biological properties have been integrated into micro/nanorobots to achieve greater maneuverability, programmability, intelligence, and multifunctionality in collective behaviors. The design and fabrication methods for hybrid robotic systems are discussed based on the material categories. In addition, their promising potential for powering motion and/or (multi-)functionality is described and the fundamental principles underlying them are explained. Finally, their extensive use in a variety of applications, including environmental remediation, (bio)sensing, therapeutics, etc., and remaining challenges and perspectives for future research are discussed.

Magnetotactic Sperm Cells for Assisted Reproduction.

Biohybrid micromotors are active microscopic agents consisting of biological and synthetic components that are being developed as novel tools for biomedical applications. By capturing motile sperm cells within engineered microstructures, they can be controlled remotely while being propelled forward by the flagellar beat. This makes them an interesting tool for reproductive medicine that can enable minimally invasive sperm cell delivery to the oocyte in vivo, as a treatment for infertility. The generation of sperm-based micromotors in sufficiently large numbers, as they are required in biomedical applications has been challenging, either due to the employed fabrication techniques or the stability of the microstructure-sperm coupling. Here, biohybrid micromotors, which can be assembled in a fast and simple process using magnetic microparticles, are presented. These magnetotactic sperm cells show a high motility and swimming speed and can be transferred between different environments without large detrimental effects on sperm motility and membrane integrity. Furthermore, clusters of micromotors are assembled magnetically and visualized using dual ultrasound (US)/photoacoustic (PA) imaging. Finally, a protocol for the scaled-up assembly of micromotors and their purification for use in in vitro fertilization (IVF) is presented, bringing them closer to their biomedical implementation.

Remotely Controlled Electrochemical Degradation of Metallic Implants.

Biodegradable medical implants promise to benefit patients by eliminating risks and discomfort associated with permanent implantation or surgical removal. The time until full resorption is largely determined by the implant's material composition, geometric design, and surface properties. Implants with a fixed residence time, however, cannot account for the needs of individual patients, thereby imposing limits on personalization. Here, an active Fe-based implant system is reported whose biodegradation is controlled remotely and in situ. This is achieved by incorporating a galvanic cell within the implant. An external and wireless signal is used to activate the on-board electronic circuit that controls the corrosion current between the implant body and an integrated counter electrode. This configuration leads to the accelerated degradation of the implant and allows to harvest electrochemical energy that is naturally released by corrosion. In this study, the electrochemical properties of the Fe-30Mn-1C/Pt galvanic cell model system is first investigated and high-resolution X-ray microcomputed tomography is used to evaluate the galvanic degradation of stent structures. Subsequently, a centimeter-sized active implant prototype is assembled with conventional electronic components and the remotely controlled corrosion is tested in vitro. Furthermore, strategies toward the miniaturization and full biodegradability of this system are presented.

A qualitative community health assessment of HIV prevention awareness in a semi-rural Latinx seasonal farm working community in South Florida.

This article explores HIV awareness and prevention in a Latinx seasonal farmworker community of south Miami-Dade County in the USA. The study took place as part of a larger community assessment that aimed to determine community needs and resources related to substance abuse, violence and HIV in the Latinx seasonal farmworker communities of south Miami-Dade County, with a particular focus on fathers' and their male sons' relationships. The study collected data on HIV knowledge and prevention, healthcare-seeking behaviours, cultural norms, and communication barriers about HIV prevention between fathers and sons. Data were collected through in-depth interviews with community leaders, two focus groups with social and health services providers, and four focus groups involving fathers and their adolescent sons. A deductive approach to data analysis was undertaken. Five major themes were identified: (1) HIVrelated knowledge and perception; (2) HIV prevention strategies; (3) barriers and needs for tailored preventive health and care services in the community; (4) stress over sex-related communication; and (5) the dominance of traditional masculine gender norms in the household and the community.

Alcohol use among adult recent Latino/a immigrants: the role of stress, forced migration, and adherence to traditional gender roles.

Background: Previous research conducted among Latino/a immigrants has shown the underlying effect that exposure to stress after immigrating to the U.S. (i.e. health access, racial/ethnic discrimination, and language barriers) has on alcohol use patterns. However, given the demographic shifts in recent immigrants, understanding the influence of stress before (i.e. poverty, healthcare, and educational opportunities) and after immigration on their alcohol use (i.e. alcohol consumption and drinking behaviors in the past 12 months) in the context of migration and traditional gender roles is warranted.Objectives: To examine the (a) cumulative effects of pre- to post-immigration stress, (b) respective moderating effects of traditional gender roles, and (c) forced migration on alcohol use for men and women.Methods: Hierarchical multiple regression and moderation analyses were conducted on a cross-sectional sample of 529 (N = 268 men, N = 261 women) adult (18-34 years) from recent Latino/a immigrants in South Florida.Results: Gender had a statistically significant difference on alcohol use, (F 527) = 18.68, p < .001, with men (p = 4.36 ± SE =.22) reporting higher alcohol use than women (p = 3.08 ± SE =.20). Post-immigration stress (ß = .12, p = .03) but not pre-migration stress had a statistically significant association with alcohol use. There is no interaction effect by traditional gender roles and forced migration on the associations between pre- to post-immigration stress and alcohol use.Conclusion: Results suggest that post-immigration stress may be a reasonable intervention target to mitigate alcohol use among recent Latino/a immigrants, particularly among men.

Alcohol Use Severity among Hispanic Emerging Adults: Examining Intragroup Marginalization, Bicultural Self-Efficacy, and the Role of Gender within a Stress and Coping Framework.

Most research on cultural stressors and alcohol has focused on intercultural stressors. Continuing to exclude intracultural stressors (e.g., intragroup marginalization) from alcohol research will yield a biased understanding of the experiences of Hispanics living in a bicultural society. As we amass more studies on intracultural stressors, research will be needed to identify mutable sociocultural factors that may mitigate the association between intracultural stressors and alcohol. To address these limitations, we examined the association between intragroup marginalization and alcohol use severity and the extent to which gender and bicultural self-efficacy may moderate this association. A convenience sample of 200 Hispanic emerging adults ages 18-25 (men = 101, women = 99) from Arizona (n = 99) and Florida (n = 101) completed a cross-sectional survey. Data were analyzed using hierarchical multiple regression and moderation analyses. Higher intragroup marginalization was associated with higher alcohol use severity. Gender functioned as a moderator whereby intragroup marginalization was associated with higher alcohol use severity among men, but not women. Also, higher social groundedness functioned as a moderator that weakened the association between intragroup marginalization and alcohol use severity. Role repertoire did not function as a moderator. Our findings are significant because they enhance the reliability of the association between intragroup marginalization and alcohol use severity, and the moderating effect of gender in this respective association. This emerging line of research suggests that alcohol interventions targeting Hispanics may have a significant limitation by not accounting for intracultural stressors.

Effect of degree of conversion on the surface properties of polymerized resin cements used for luting glass fiber posts.

STATEMENT OF PROBLEM: Lack of conversion of resin cements for luting glass fiber posts in deeper levels of the root canal may compromise clinical performance. PURPOSE: The purpose of this in vitro study was to evaluate the effect of the degree of conversion on the surface properties of dual-polymerized resin cements used for cemented glass fiber posts according to the root level. MATERIAL AND METHODS: Fifty maxillary central incisor teeth were endodontically treated, and glass fiber posts were cemented using the following systems: self-adhesive dual-polymerized resin luting cement (RelyX U200) and dual-polymerizing flowable core and a post luting system (Rebilda DC) with a self-etching adhesive (Futurabond DC). The degree of conversion was determined via attenuated total reflectance and Fourier transform infrared spectroscopy, and surface microhardness and cement film thickness were measured. The intraradicular fit was evaluated with microscopy. All tests were performed in the coronal, middle, and apical third of the root canal. Statistical analysis was done with ANOVA and the multiple comparison Tukey test (α=.05). RESULTS: The degree of conversion was higher in the coronal third using Rebilda DC (65.3 ±4.8%) than RelyX U200 (38.7 ±5.3%) (P<.05); on both resin cements, these values decreased from the coronal to the apical third (30.9 ±3.7%, 61.9 ±8.7%, respectively). The cement film thickness was higher for RelyX U200 in the 3 thirds than for Rebilda DC; significant differences (P<.05) were recorded in both cementing systems in the coronal and apical thirds. In the middle third, no significant differences were observed (P>.05). The mean surface microhardness values increased in the coronal thirds and decreased with increasing root canal depth. The marginal seal in the coronal thirds and the intraradicular fit in the middle thirds showed closer adaptation; however, some tags were observed in the interface resin cement and radicular dentin. Gap and tag formations were observed in the apical third. CONCLUSIONS: Depending on the root canal third, the surface properties of dual-polymerized resin cements are influenced by the degree of conversion.

Early trajectories of cigarette and ENDS use among young adult recent Latino immigrants to U.S.

Background: Recent Latino immigrants (RLIs) to the U.S. have shown high smoking rates during their first year since arrival, raising concern about future escalation of tobacco use.Objective: To examine trajectories of cigarette and Electronic nicotine delivery systems (ENDS) use among RLIs from pre-immigration (T0) through their first (T1) and second (T2) year in the U.S.Methods: Data originated from a longitudinal study of 540 (50% females) RLIs aged 18-34. Inclusion criteria was residing in Miami/Dade County (MDC), and having immigrated from a Latin American country within the past year. Trajectories were identified by using the Proc Traj procedure (SAS©, v 9.4).Results: Rates of cigarette use per month declined from 11.8 days/month in T0 to 4.9 d/m in T2. Rates for ENDS use however, increased from T0 (1.1 d/m) to T1 (1.8 d/m) and then lowered back to 0.9 d/m in T2. Four separate cigarette and e-cigarette use trajectories were identified. Only one of them showed increase in cigarette (10.6% of RLIs), and ENDS use (4.5% of RLIs). Being male, and not completing high school were significant factors in explaining smoking trajectories. Being younger than 30 years old was largely associated with ENDS use. No evidence of a substitution effect between cigarette and ENDS use was found.Discussion/Conclusions: Interventions to discourage tobacco use among Latino immigrants should begin early in the immigration process, aimed to preserve initial reductions and dissuade those at risk of increased tobacco use overtime.

Alcohol use severity among recent Latino immigrants: Associations of acculturation, family history of alcohol use and alcohol outcome expectancies.

Having a family history of alcohol (FH+) use is a well-documented risk factor for alcohol use and alcohol related problems. However, there are limited studies examining the impact of FH + on current alcohol use among Latino immigrants. This study aimed to determine the influence of having a FH + on current alcohol use among Latino immigrants and the influence of alcohol outcome expectancies (AOEs) and acculturation on this relationship. This is a longitudinal secondary data analysis of data from the Recent Latino Immigrant Study (RLIS), the first community-based cohort study to examine pre- to post-immigration alcohol use trajectories of young adult Latino immigrants. Linear mixed models were performed to assess the association between various pre- and post-immigration factors and alcohol use among Latino immigrants. There were 518 young adult Latino immigrants with 18.7% reporting a FH + with those with a FH + having higher mean AUDIT score compared to those without (4.74 vs. 3.81; p = 0.028). Positive AOEs were associated with increase AUDIT scores. FH + individuals with greater positive AOEs experienced higher AUDIT scores compared to FH- individuals. Family cohesion was protective against alcohol use while endorsement of Americansism was associated with increased alcohol use. Theses results provide the framework for more in-depth exploration regarding the influences of FH+, AOEs, and acculturation have on the alcohol use among Latino immigrants. Future longitudinal research studies should account for whether traditional cultural values mediate or moderate the relationship between a FH+, AOE, and alcohol use of Latino immigrants.

The role of neuropeptides in regulating ecdysis and reproduction in the hemimetabolous insect Rhodnius prolixus.

In ecdysozoan animals, moulting entails the production of a new exoskeleton and shedding of the old one during ecdysis. It is induced by a pulse of ecdysone that regulates the expression of different hormonal receptors and activates a peptide-mediated signalling cascade. In Holometabola, the peptidergic cascade regulating ecdysis has been well described. However, very little functional information regarding the neuroendocrine regulation of ecdysis is available for Hemimetabola, which display an incomplete metamorphosis. We use Rhodnius prolixus as a convenient experimental model to test two hypotheses: (1) the role of neuropeptides that regulate ecdysis in Holometabola is conserved in hemimetabolous insects; and (2) the neuropeptides regulating ecdysis play a role in the regulation of female reproduction during the adult stage. The RNA interference-mediated reduction of ecdysis triggering hormone (ETH) mRNA levels in fourth-instar nymphs resulted in lethality at the expected time of ecdysis. Unlike in holometabolous insects, knockdown of eth and orcokinin isoform A (oka) did not affect oviposition in adult females, pointing to a different endocrine regulation of ovary maturation. However, eth knockdown prevented egg hatching. The blockage of egg hatching appears to be a consequence of embryonic ecdysis failure. Most of the first-instar nymphs hatched from the eggs laid by females injected with dsRNA for eclosion hormone (dsEH), crustacean cardioactive peptide (dsCCAP) and dsOKA died at the expected time of ecdysis, indicating the crucial involvement of these genes in post-embryonic development. No phenotypes were observed upon corazonin (cz) knockdown in nymphs or adult females. The results are relevant for evolutionary entomology and could reveal targets for neuropeptide-based pest control tools.

Acting with awareness moderates the association between lifetime exposure to interpersonal traumatic events and craving via trauma symptoms: a moderated indirect effects model.

BACKGROUND: History of exposure to traumatic events (ETE) is common among women in substance use disorder (SUD) treatment and is related to craving. We examined whether ETE (i.e., emotional, physical, sexual abuse) in childhood, adulthood, or both is related to craving via trauma symptoms and how trait mindfulness might attenuate this association. METHODS: Baseline data from a larger randomized clinical trial of a mindfulness-based intervention for women (N = 245) in SUD treatment were used. Inclusion criteria were: 18-65 years of age, SUD diagnosis, English fluency, no cognitive impairment, and willingness to be audio recorded and provide consent. Demographics and validated measures of ETE, posttraumatic stress symptoms, trait mindfulness, and substance use craving were collected via in-person interviews. Descriptive statistics, correlational analysis, and relative direct, indirect, and conditional indirect effects models were run. RESULTS: Most participants identified as Hispanic (58.5%), had at least a high school education (52.2%), with a mean age of 32.2. Women reported ETE in childhood only (20.4%), adulthood only (17.5%), both childhood and adulthood (50.0%), and never (11.4%). Compared to women with ETE in both childhood and adulthood, those with exposure in adulthood only (ß = -.10, 95% CI = -.20, -.02) or no exposure (ß = -.11, 95% CI = -.23, -.03; [∆R2= .347, F(8, 245) = 15.7, p < .001) had lower craving via lower trauma symptomatology but no difference when compared to those with ETE only in childhood. Acting with awareness moderated this indirect effect (∆R2 = .04, F(3, 245) = 4.66, p = .004. At low levels of awareness, women with ETE during both childhood and adulthood reported higher craving via trauma symptomatology than women with no exposure or only adulthood exposure. CONCLUSIONS: Low levels of acting with awareness may worsen trauma symptoms after ETE, which in turn may lead to more craving for women in substance use treatment. Despite a small moderating effect size, acting with awareness may have clinical significance due to the prevalence of trauma symptoms among women in SUD treatment.

Depressive symptoms among recent Latinx immigrants in South Florida: The role of premigration trauma and stress, postimmigration stress, and gender.

In the past decade, recent Latinx immigrants (RLIs) from South and Central America have arrived in the United States seeking asylum from countries affected by war, political upheaval, and high crime and poverty rates. The premigration stress and trauma they experience are further compounded by postimmigration stress due to discrimination, lack of access to health care, and financial instability. Evidence suggests RLIs who experience such stress and trauma have an increased risk of developing depressive symptoms. We examined the combined effect of premigration stress and trauma and postimmigration stress on postimmigration depressive symptoms; we also explored the moderating effect of gender. Hierarchical multiple regression and moderation analyses were conducted on a cross-sectional sample of 540 young adult RLIs (age range: 18-34 years, 50.2% men) in South Florida. Higher levels of postimmigration stress, ß = .37, p < .001, were associated with increased postimmigration depressive symptoms. No significant associations emerged between premigration stress and trauma and postimmigration depressive symptoms. Moderation analyses revealed no significant interaction effect of gender. Post hoc analyses indicated that country/region of origin moderated the relation between postimmigration stress and depressive symptoms such that the association was stronger among Venezuelan, ß = 1.51, p < .001; other South American, ß = 1.06, p < .001; and Central American/Mexican RLIs, ß = 1.38, p < .001, compared with Caribbean RLIs, ß = .45, p  = .122. These findings suggest that interventions focused on addressing postimmigration stress early in the immigration process can potentially lower subsequent depressive symptoms among RLIs.

Impact of pre-migration assets and pre-migration trauma on acculturative stress among recent Latinx immigrant young adults.

BACKGROUND: Pre-migration trauma is associated with adverse mental health outcomes among Latinx immigrants. Pre-migration assets like family cohesion and social support may promote positive mental health outcomes in this population. The current study aims to identify the cumulative and interaction effects of pre-migration trauma, social support, and family cohesion on acculturative stress among recent Latinx immigrants (RLIs). METHOD: The current study utilizes baseline data from an on-going longitudinal study following 540 RLIs during their initial 3 years in the U.S. Simple main effects of the predictor variables on acculturative stress were estimated using hierarchical multiple regression (HMR). Predictor variables were entered into the HMR model as follows: (1) demographic variables were entered in the first block, (2) family cohesion and social support in the second block and (3) pre-migration trauma in the third block. Interaction effects between family cohesion and social support on the association between pre-migration trauma and acculturative stress were examined. RESULTS: Results showed that 20.6% of the variance of acculturative stress was explained by the predictor variables entered into the HMR model. The first predictor block included demographic variables and explained 13.5% of the variability in acculturative stress, R2 = 13.5, F(6, 521) = 13.55, p < .001. The second block added family cohesion and social support to the HMR model and showed an ΔR2 of 4.5%, R2 = 18.0, F(8, 519) = 14.22, p < .001. The third block added pre- migration trauma to the HMR model and showed an ΔR2 change of 2.6%, R2 = 20.6, F(9, 518) = 14.93, p < .001. Significant interaction effects were found for family cohesion among documented RLIs. Social support was not a significant moderator. CONCLUSION: Study findings suggest pre-migration resources such as family cohesion and social support may ameliorate post-immigration acculturative stress among RLI, while pre-migration trauma, may exacerbate acculturative stress.

Associations between gender norms and HIV self-efficacy among Latina immigrants in a farmworker community.

Latina immigrant farmworkers are a vulnerable and understudied population that face a host of socio-cultural and structural barriers that place them at risk for HIV infection. Cultural factors, including traditional gender roles (egalitarian and marianismo) that frequently inhibit communication between partners and promote rigid roles, may particularly affect self-efficacy for HIV prevention among this population.Objective: This study examines the impact of women's gender norms on HIV knowledge and safe sex negotiation skills, along with the moderating influence of HIV self-efficacy among Latina immigrants in a farmworker community.Design: The current cross-sectional analysis study examines data from a sample (N = 157) of mostly undocumented Latina immigrant farmworkers in South Miami-Dade County, Florida. Analysis was performed on secondary data obtained from baseline collected on an intervention pilot study. Measures of traditional American (egalitarian) and Latina (marianismo) gender norms, HIV self-efficacy, and HIV knowledge, as well as key demographic variables were collected.Results: Findings revealed higher American (egalitarian) gender norms directly and indirectly predict higher HIV prevention factors. Additionally, HIV self-efficacy did not mediate effects of marianismo on HIV risk.Conclusion: Findings conclude that HIV prevention can be especially challenging due to socio-cultural and traditional gender norms faced by Latinas in farm working communities and that such norms should be taken into account when developing and adapting culturally appropriate interventions to reduce HIV related risk behaviors for Latinas residing in urban or farm working communities.

Pre- and post-immigration factors associated with cigarette use among young adult recent Latinx immigrants during their initial year in the U.S.

Background: Evidence indicates escalating rates of cigarette use among foreign-born Latinx as their time in the U.S increases. As such, it's important to understand shifts in pre- to post-immigration smoking patterns early in the immigration process and its associated factors.Objectives: To examine 1) cigarette use among recent Latinx immigrants (RLIs) during their initial year in the U.S.; 2) whether cigarette use after immigration is influenced by smoking patterns in immigrant's country of origin; and 3) associations between pre/post immigration sociocultural factors and changes in cigarette use after immigration.Methods: Baseline data were utilized from an on-going longitudinal study of 540 young adult (50% females) RLIs. Inclusion criteria was being between ages 18 and 34, residing in Miami-Dade County, Florida, and having immigrated from a Latin American country within the past yearResults: Approximately 31% of participants reported being smokers in their country of origin while 26% were current smokers (while residing in the U.S). Post-immigration cigarette use was substantially influenced by country of origin cigarette use (V = .68); 84% of pre-immigration smokers reported no change in smoking frequency, while 11% lowered and 6% increased their cigarette use post-immigration. Reduction in smoking after immigration was more likely among participants with higher pre-immigration social support (aOR = 1.87) and less likely among those residing in high-crime neighborhoods (aOR = .84).Conclusion: Interventions aimed to discourage cigarette use should begin early in the immigration process and account for RLIs' pre-immigration smoking patterns. Interpersonal supports and neighborhood contextual factors should be considered when developing smoking cessation programs with this population.

Prescription Drug and Cannabis Use among Recent Latinx Immigrants Pre- and Post-Immigration to the US.

Introduction: Shifts in the sociopolitical context of Latin America have led to steep increases in recent Latinx immigrants (RLI) arriving in the US within the context of forced migration. Yet, little is known about how adverse experiences of RLIs before and after immigration may impact their health including drug use. The purpose of this study was to examine prescription drug and cannabis use before and just after immigration among RLIs and how this drug use is influenced by pre-and post-immigration factors. Methods: This study utilized baseline data from a study examining pre- to post-immigration drinking and driving trajectories among RLI in the United States (US). Baseline criteria included: self-identifying as a Latinx immigrant, 18 - 34 years old, who recently immigrated from a Latin American country. Multivariate logistic regression was conducted to determine predictors of drug use both prior to and after immigrating. Results: There were 540 RLI, 50.2% male and 47.8% subjected to forced migration. Prescription and illicit drug use decreased post-immigration with sedatives being the most common. Higher levels of education was associated with increased odds of pre-immigration prescription drug use and cannabis use. Those experiencing forced migration were more likely to engage in prescription drug use before and after immigration, while no associations were found for cannabis use. Conclusion: Findings suggest a need for increased substance use and mental health services among RLIs arriving within the context of forced migration. More research is needed to understand the trajectories of drug use among RLI as their time in the US increases.

Influences of immigration stress and occupational exploitation on Latina seasonal workers' substance use networks: a qualitative study.

US female Latina seasonal farm workers (LSW) are a medically underserved community experiencing severe health disparities. We explored the relationship between alcohol and prescription medication, and LSW social networks using a qualitative approach. In 2015, this study used convenience sampling to recruit 28 LSWs in South Florida for three focus group discussions in Spanish. Focus groups were translated to English for analysis, which employed a general inductive approach. Themes included prescription medication distribution within networks, spirituality/religion practice with friends and family, and alcohol use with friends. Substance abuse prevention and treatment interventions should account for the unique needs of LSW.

Ethnic discrimination and psychological stress among Hispanic emerging adults: Examining the moderating effects of distress tolerance and optimism.

Hispanic emerging adults are often exposed to ethnic discrimination, yet little is known about coping resources that may mitigate the effects of ethnic discrimination on psychological stress in this rapidly growing population. As such, this study aims to examine (1) the associations of ethnic discrimination, distress tolerance, and optimism with psychological stress and (2) the moderating effects of distress tolerance and optimism on the association between ethnic discrimination and psychological stress. Data were drawn from a cross-sectional study of 200 Hispanic adults ages 18-25, recruited from two urban counties in Arizona and Florida. Hierarchical multiple regression and moderation analyses were utilized to examine these associations and moderated effects. Findings indicated that higher optimism was associated with lower psychological stress. Conversely, higher ethnic discrimination was associated with higher psychological stress. Moderation analyses indicated that both distress tolerance and optimism moderated the association between ethnic discrimination and psychological stress. These study findings add to the limited literature on ethnic discrimination among Hispanic emerging adults and suggest that distress tolerance may be a key intrapersonal factor that can protect Hispanic emerging adults against the psychological stress often resulting from ethnic discrimination.

Switching Propulsion Mechanisms of Tubular Catalytic Micromotors.

Different propulsion mechanisms have been suggested for describing the motion of a variety of chemical micromotors, which have attracted great attention in the last decades due to their high efficiency and thrust force, enabling several applications in the fields of environmental remediation and biomedicine. Bubble-recoil based motion, in particular, has been modeled by three different phenomena: capillary forces, bubble growth, and bubble expulsion. However, these models have been suggested independently based on a single influencing factor (i.e., viscosity), limiting the understanding of the overall micromotor performance. Therefore, the combined effect of medium viscosity, surface tension, and fuel concentration is analyzed on the micromotor swimming ability, and the dominant propulsion mechanisms that describe its motion more accurately are identified. Using statistically relevant experimental data, a holistic theoretical model is proposed for bubble-propelled tubular catalytic micromotors that includes all three above-mentioned phenomena and provides deeper insights into their propulsion physics toward optimized geometries and experimental conditions.

Rolled-Up Metal Oxide Microscaffolds to Study Early Bone Formation at Single Cell Resolution.

Titanium and its alloys are frequently used to replace structural components of the human body due to their high mechanical strength, low stiffness, and biocompatibility. In particular, the use of porous materials has improved implant stabilization and the promotion of bone. However, it remains unclear which material properties and geometrical cues are optimal for a proper osteoinduction and osseointegration. To that end, transparent tubular microscaffolds are fabricated, mimicking the typical pores of structural implants, with the aim of studying early bone formation and cell-material interactions at the single cell level. Here, a ß-stabilized alloy Ti-45Nb (wt%) is used for the microscaffold's fabrication due to its elastic modulus close to that of natural bone. Human mesenchymal stem cell migration, adhesion, and osteogenic differentiation is thus investigated, paying particular attention to the CaP formation and cell-body crystallization, both analyzed via optical and electron microscopy. It is demonstrated that the developed platform is suited for the long-term study of living single cells in an appropriate microenvironment, obtaining in the process deeper insights on early bone formation and providing cues to improve the stability and biocompatibility of current structural implants.