Task space adaptation via the learning of gait controllers of magnetic soft millirobots.

Untethered small-scale soft robots have promising applications in minimally invasive surgery, targeted drug delivery, and bioengineering applications as they can directly and non-invasively access confined and hard-to-reach spaces in the human body. For such potential biomedical applications, the adaptivity of the robot control is essential to ensure the continuity of the operations, as task environment conditions show dynamic variations that can alter the robot's motion and task performance. The applicability of the conventional modeling and control methods is further limited for soft robots at the small-scale owing to their kinematics with virtually infinite degrees of freedom, inherent stochastic variability during fabrication, and changing dynamics during real-world interactions. To address the controller adaptation challenge to dynamically changing task environments, we propose using a probabilistic learning approach for a millimeter-scale magnetic walking soft robot using Bayesian optimization (BO) and Gaussian processes (GPs). Our approach provides a data-efficient learning scheme by finding the gait controller parameters while optimizing the stride length of the walking soft millirobot using a small number of physical experiments. To demonstrate the controller adaptation, we test the walking gait of the robot in task environments with different surface adhesion and roughness, and medium viscosity, which aims to represent the possible conditions for future robotic tasks inside the human body. We further utilize the transfer of the learned GP parameters among different task spaces and robots and compare their efficacy on the improvement of data-efficient controller learning.

Assessment of the effectiveness of genital infection awareness training provided to women based on the IMB model.

BACKGROUND: Genital infections are one of the most common reasons for a hospital visit in the scope of reproductive health problems. The information-motivation-behavioral skills (IMB), therefore, is an appropriate model to provide women with accurate genital hygiene behaviors and develop effective sexual and reproductive health training programs. AIMS: This interventional study was conducted to assess the effectiveness of genital infection awareness training provided to women based on the IMB model. MATERIALS AND METHODS: Study sample consisted of 62 women (nexperimental= 31, ncontrol= 31) who were chosen based on a nonprobability sampling method from vocational courses of Ankara Keçiören municipality. The data collection form developed by the researchers, knowledge evaluation questions (KEQ), and genital hygiene behavior inventory (GHBI) were used to collect data. Data were obtained at training centers and through phone interviews. Another interview was conducted 1 month later and posttest procedures were completed. The Chi-square test, McNemar's, Mann-Whitney U test, and Wilcoxon Signed-Rank tests were used to calculate mean scores. RESULTS: The mean (SD) age was 39.1 (8.4) years for the women in the experimental group and 37.5 (6.7) for the women in the control group (P = 0.481). Pretest knowledge mean scores M (SD)experimental = 15.7 (2.4); and GHBI mean scores M (SD)experimental= 76.9 (11.1) were calculated. Mean scores showed an increase after the training in the experimental group [M (SD)post-test= 19.1 (1.2); M (SD)GHBI= 94.7 (2.6)] (P < 0.001). CONCLUSION: Based on these findings, it was concluded that the genital infection awareness training provided to women based on the IMB model, improved knowledge and acted as a positive reinforcer for the hygiene behaviors of the women.

Adolescent exposure to oxytocin, but not the selective oxytocin receptor agonist TGOT, increases social behavior and plasma oxytocin in adulthood.

There are indications that exposing adolescent rodents to oxytocin (OT) may have positive "trait-changing" effects resulting in increased sociability and decreased anxiety that last well beyond acute drug exposure and into adulthood. Such findings may have relevance to the utility of OT in producing sustained beneficial effects in human psychiatric conditions. The present study further examined these effects using an intermittent regime of OT exposure in adolescence, and using Long Evans rats, that are generally more sensitive to the acute prosocial effects of OT. As OT has substantial affinity for the vasopressin V1a receptor (V1aR) in addition to the oxytocin receptor (OTR), we examined whether a more selective peptidergic OTR agonist - [Thr4, Gly7]-oxytocin (TGOT) - would have similar lasting effects on behavior. Male Long Evans rats received OT or TGOT (0.5-1mg/kg, intraperitoneal), once every three days, for a total of 10 doses during adolescence (postnatal day (PND) 28-55). Social and anxiety-related behaviors were assessed during acute administration as well as later in adulthood (from PND 70 onwards). OT produced greater acute behavioral effects than TGOT, including an inhibition of social play and reduced rearing, most likely reflecting primary sedative effects. In adulthood, OT but not TGOT pretreated rats displayed lasting increases in social interaction, accompanied by an enduring increase in plasma OT. These findings confirm lasting behavioral and neuroendocrine effects of adolescent OT exposure. However, the absence of such effects with TGOT suggests possible involvement of the V1aR as well as the OTR in this example of developmental neuroplasticity.

Bayesian Machine Learning for Efficient Minimization of Defects in ALD Passivation Layers.

Atomic layer deposition (ALD) is an enabling technology for encapsulating sensitive materials owing to its high-quality, conformal coating capability. Finding the optimum deposition parameters is vital to achieving defect-free layers; however, the high dimensionality of the parameter space makes a systematic study on the improvement of the protective properties of ALD films challenging. Machine-learning (ML) methods are gaining credibility in materials science applications by efficiently addressing these challenges and outperforming conventional techniques. Accordingly, this study reports the ML-based minimization of defects in an ALD-Al2O3 passivation layer for the corrosion protection of metallic copper using Bayesian optimization (BO). In all experiments, BO consistently minimizes the layer defect density by finding the optimum deposition parameters in less than three trials. Electrochemical tests show that the optimized layers have virtually zero film porosity and achieve five orders of magnitude reduction in corrosion current as compared to control samples. Optimized parameters of surface pretreatment using Ar/H2 plasma, the deposition temperature above 200 °C, and 60 ms pulse time quadruple the corrosion resistance. The significant optimization of ALD layers presented in this study demonstrates the effectiveness of BO and its potential outreach to a broader audience, focusing on different materials and processes in materials science applications.

Learning of Sub-optimal Gait Controllers for Magnetic Walking Soft Millirobots.

Untethered small-scale soft robots have promising applications in minimally invasive surgery, targeted drug delivery, and bioengineering applications as they can access confined spaces in the human body. However, due to highly nonlinear soft continuum deformation kinematics, inherent stochastic variability during fabrication at the small scale, and lack of accurate models, the conventional control methods cannot be easily applied. Adaptivity of robot control is additionally crucial for medical operations, as operation environments show large variability, and robot materials may degrade or change over time, which would have deteriorating effects on the robot motion and task performance. Therefore, we propose using a probabilistic learning approach for millimeter-scale magnetic walking soft robots using Bayesian optimization (BO) and Gaussian processes (GPs). Our approach provides a data-efficient learning scheme to find controller parameters while optimizing the stride length performance of the walking soft millirobot robot within a small number of physical experiments. We demonstrate adaptation to fabrication variabilities in three different robots and to walking surfaces with different roughness. We also show an improvement in the learning performance by transferring the learning results of one robot to the others as prior information.

Hormonal effects on the secretion and glycoform profile of corticosteroid-binding globulin.

Corticosteroid-binding globulin (CBG) is a plasma glycoprotein that is primarily synthesized in the liver and binds cortisol and progesterone with high affinity. In this study, a CBG secreting hepatocellular carcinoma derived cell line (HepG2) was used to investigate the hormonal regulation of hepatic CBG synthesis. HepG2 cells were grown for 72 h in 30, 300 and 3000 nM concentrations of estradiol (E2), testosterone (T), insulin, thyroxin (T4) and dexamethasone (DMZ) and the secreted CBG quantified by a novel enzyme-linked immunosorbent assay (ELISA). Two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) was carried out to determine the effects of these hormones on the relative distribution of CBG glycoforms. Insulin, T4 and high concentrations of E2 decreased the secretion of CBG by HepG2 cells (p<0.05). Ethanol, the solvent used for E2, T and DMZ, also significantly attenuated CBG secretion. 2D-PAGE resolved 13-14 glycoforms of CBG produced by HepG2 cells. Insulin caused a reduction in the synthesis of more acidic, while T4 and DMZ decreased the production of more basic CBG glycoforms. Stimulation with E2 resulted in the synthesis of additional isoforms of increased acidity, which may represent a type of CBG only seen during pregnancy in vivo. Possible physiological implications of these findings are discussed.

Retroperitoneal trapdoor endarterectomy for paravisceral "coral-reef" aortic plaque.

A 67-year-old woman presented to the emergency room with progressive claudication, chest pain, and flash-pulmonary edema. Her past medical history was significant for poorly controlled hypertension requiring multiple antihypertensive medications, renal insufficiency, and tobacco abuse. Diagnostic evaluation revealed an extensive exophytic plaque localized to the paravisceral aorta resulting in high-grade stenoses of the proximal aorta as well as the celiac, superior mesenteric, and left renal arteries. She underwent surgical revascularization through a retroperitoneal aortic exposure and trapdoor aortic endarterectomy, the technical conduct of which is described in this manuscript. The patient recovered uneventfully and experienced resolution of her claudication and pulmonary symptoms, improved blood pressure control, and normalization of her creatinine. Review of the medical literature pertaining to management of proximal occlusive disease of the abdominal aorta is discussed.

Slip in the 1857 and earlier large earthquakes along the Carrizo Plain, San Andreas Fault.

The moment magnitude (Mw) 7.9 Fort Tejon earthquake of 1857, with a approximately 350-kilometer-long surface rupture, was the most recent major earthquake along the south-central San Andreas Fault, California. Based on previous measurements of its surface slip distribution, rupture along the approximately 60-kilometer-long Carrizo segment was thought to control the recurrence of 1857-like earthquakes. New high-resolution topographic data show that the average slip along the Carrizo segment during the 1857 event was 5.3 +/- 1.4 meters, eliminating the core assumption for a linkage between Carrizo segment rupture and recurrence of major earthquakes along the south-central San Andreas Fault. Earthquake slip along the Carrizo segment may recur in earthquake clusters with cumulative slip of approximately 5 meters.

Climate-modulated channel incision and rupture history of the San Andreas Fault in the Carrizo Plain.

The spatial and temporal distribution of fault slip is a critical parameter in earthquake source models. Previous geomorphic and geologic studies of channel offset along the Carrizo section of the south central San Andreas Fault assumed that channels form more frequently than earthquakes occur and suggested that repeated large-slip earthquakes similar to the 1857 Fort Tejon earthquake illustrate typical fault behavior. We found that offset channels in the Carrizo Plain incised less frequently than they were offset by earthquakes. Channels have been offset by successive earthquakes with variable slip since ~1400. This nonuniform slip history reveals a more complex rupture history than previously assumed for the structurally simplest section of the San Andreas Fault.

Evaluation of biodistribution by local versus systemic administration of 99mTc-labeled pamidronate.

BACKGROUND: There is an emerging interest in utilizing local and systemic administration of bisphosphonates in orthopedics. The primary objective of this study was to use (99m)Tc-pamidronate ((99m)Tc-PAM) as a tool and compare bone and tissue uptake by local versus systemic administration. METHODS: (99m)Tc-PAM was administered intravenously (i.v.), subcutaneously (s.c.) and by direct application (d.a.) on a surgically exposed and fractured femur (d.a.#f). The animals were imaged at 2 h and 24 h after administration and then killed. Organs were harvested, and their radioactivity was estimated. Specific uptake in the right femur was compared between groups, as was systemic exposure to (99m)Tc PAM. RESULTS: Bone uptake of (99m)Tc-PAM in the i.v. and s.c. groups was 2.2 +/- 0.15 and 0.65 +/- 0.07% ID/g, respectively, at the 2 h time point. Uptake by surgically exposed right femur (d.a) was 5.15 +/- 0.26% ID/g, 134% higher than the femoral uptake by the i.v. method (P < 0.05). In the presence of exposed bone when the femur was fractured (d.a.#f), the uptake was 7.89 +/- 0.46% ID/g, a further 50% increase (P < 0.05). The uptake of (99m)Tc-PAM increased after 24 h of application to 2.4 +/- 0.15, 1.53 +/- 0.09, 7.94 +/- 0.99, and 13.2 +/- 0.80% ID/g) for i.v., s.c., d.a., and d.a.#f methods, respectively. The increases in uptake for the d.a. methods were significantly higher than for the local methods at the 24-h time point (P < 0.05). Although renal uptake was comparable with the i.v. and s.c. methods (0.22 +/- 0.03 and 0.22 +/- 0.04% ID/g), it was significantly lower with the d.a. methods (0.05 +/- 0.07 and 0.16 +/- 0.07% ID/g) (P < 0.05). The corresponding urinary excretion was 55%, 45%, 36%, and 35% of the injected dose at 24 h. CONCLUSIONS: The results indicate that the bone uptake of (99m)Tc-PAM was significantly higher (P = 0.001) and the kidney uptake significantly lower (P = 0.004) with the d.a. methods than with the i.v. or s.c. method. The findings indicate the need for further study into the potential of local administration of bisphosphonates in the presence of orthopedic indications.

Comparison of molecular mechanisms mediating cell contact phenomena in model developmental systems: an exploration of universality.

Are there universal molecular mechanisms associated with cell contact phenomena during metazoan ontogenesis? Comparison of adhesion systems in disparate model systems indicates the existence of unifying principles. Requirements for multicellularity are (a) the construction of three-dimensional structures involving a crucial balance between adhesiveness and motility; and (b) the establishment of integration at molecular, cellular, tissue, and organismal levels of organization. Mechanisms for (i) cell-cell and cell-substrate adhesion, (ii) cell movement, (iii) cell-cell communication, (iv) cellular responses, (v) regulation of these processes, and (vi) their integration with patterning, growth, and other developmental processes are all crucial to metazoan development, and must have been present for the emergence and radiation of Metazoa. The principal unifying themes of this review are the dynamics and regulation of cell contact phenomena. Our knowledge of the dynamic molecular mechanisms underlying cell contact phenomena remains fragmentary. Here we examine the molecular bases of cell contact phenomena using extant model developmental systems (representing a wide range of phyla) including the simplest i.e. sponges, and the eukaryotic protist Dictyostelium discoideum, the more complex Drosophila melanogaster, and vertebrate systems. We discuss cell contact phenomena in a broad developmental context. The molecular language of cell contact phenomena is complex; it involves a plethora of structurally and functionally diverse molecules, and diverse modes of intermolecular interactions mediated by protein and/or carbohydrate moieties. Reasons for this are presumably the necessity for a high degree of specificity of intermolecular interactions, the requirement for a multitude of different signals, and the apparent requirement for an increasingly large repertoire of cell contact molecules in more complex developmental systems, such as the developing vertebrate nervous system. However, comparison of molecular models for dynamic adhesion in sponges and in vertebrates indicates that, in spite of significant differences in the details of the way specific cell-cell adhesion is mediated, similar principles are involved in the mechanisms employed by members of disparate phyla. Universal requirements are likely to include (a) rapidly reversible intermolecular interactions; (b) low-affinity intermolecular interactions with fast on-off rates; (c) the compounding of multiple intermolecular interactions; (d) associated regulatory signalling systems. The apparent widespread employment of molecular mechanisms involving cadherin-like cell adhesion molecules suggests the fundamental importance of cadherin function during development, particularly in epithelial morphogenesis, cell sorting, and segregation of cells.

Cell adhesion during the migratory slug stage of Dictyostelium discoideum.

Prespore-specific Antigen (PsA) is selectively expressed on the surface of prespore cells at the multicellular migratory slug stage of Dictyostelium discoideum development. It is a developmentally regulated glycoprotein that is anchored to the cell membrane through a glycosyl phosphatidylinositol (GPI) anchor. We present the results of an in vitro immunological investigation of the hypothesis that PsA functions as a cell adhesion molecule (CAM), and of a ligand-binding assay indicating that PsA has cell membrane binding partner(s). This is the first evidence to implicate a direct role for a putative CAM in cell-cell adhesion during the multicellular migratory slug stage of D. discoideum development. Cell-cell adhesion assays were carried out in the presence or absence of the monoclonal antibody (mAb) MUD1 that has a single antigenic determinant: a peptide epitope on PsA. These assays showed specific inhibition of cell-cell adhesion by MUD1. Further, it was found that a purified recombinant form of PsA (rPsA), can neutralize the inhibitory effect of MUD1; the inhibitory effect on cell-cell adhesion is primarily due to the blocking of PsA by the mAb. The resistance of aggregates to dissociation in the presence of 10 mM EDTA (ethylenediamintetraacetic acid) indicates that PsA mediates EDTA-stable cell-cell contacts, and that PsA-mediated cell adhesion is likely to be independent of divalent cations such as Ca(2+) or Mg(2+).