Electrohydraulic musculoskeletal robotic leg for agile, adaptive, yet energy-efficient locomotion.

Robotic locomotion in unstructured terrain demands an agile, adaptive, and energy-efficient architecture. To traverse such terrains, legged robots use rigid electromagnetic motors and sensorized drivetrains to adapt to the environment actively. These systems struggle to compete with animals that excel through their agile and effortless motion in natural environments. We propose a bio-inspired musculoskeletal leg architecture driven by antagonistic pairs of electrohydraulic artificial muscles. Our leg is mounted on a boom arm and can adaptively hop on varying terrain in an energy-efficient yet agile manner. It can also detect obstacles through capacitive self-sensing. The leg performs powerful and agile gait motions beyond 5 Hz and high jumps up to 40 % of the leg height. Our leg's tunable stiffness and inherent adaptability allow it to hop over grass, sand, gravel, pebbles, and large rocks using only open-loop force control. The electrohydraulic leg features a low cost of transport (0.73), and while squatting, it consumes only a fraction of the energy (1.2 %) compared to its conventional electromagnetic counterpart. Its agile, adaptive, and energy-efficient properties would open a roadmap toward a new class of musculoskeletal robots for versatile locomotion and operation in unstructured natural environments.

Vision-controlled jetting for composite systems and robots.

Recreating complex structures and functions of natural organisms in a synthetic form is a long-standing goal for humanity1. The aim is to create actuated systems with high spatial resolutions and complex material arrangements that range from elastic to rigid. Traditional manufacturing processes struggle to fabricate such complex systems2. It remains an open challenge to fabricate functional systems automatically and quickly with a wide range of elastic properties, resolutions, and integrated actuation and sensing channels2,3. We propose an inkjet deposition process called vision-controlled jetting that can create complex systems and robots. Hereby, a scanning system captures the three-dimensional print geometry and enables a digital feedback loop, which eliminates the need for mechanical planarizers. This contactless process allows us to use continuously curing chemistries and, therefore, print a broader range of material families and elastic moduli. The advances in material properties are characterized by standardized tests comparing our printed materials to the state-of-the-art. We directly fabricated a wide range of complex high-resolution composite systems and robots: tendon-driven hands, pneumatically actuated walking manipulators, pumps that mimic a heart and metamaterial structures. Our approach provides an automated, scalable, high-throughput process to manufacture high-resolution, functional multimaterial systems.

Embolic occlusion of internal carotid artery in conscious rats: Immediate effects of cerebral ischemia.

In most preclinical models of focal ischemic stroke, vascular occlusion is performed under general anesthesia. However, anesthetic agents exert confounding effects on mean arterial blood pressure (MABP), cerebrovascular tone, oxygen demand, and neurotransmitter receptor transduction. Moreover, the majority of studies do not use a blood clot, which more fully models embolic stroke. Here, we developed a blood clot injection model to produce large cerebral artery ischemia in unanesthetized rats. Under isoflurane anesthesia, an indwelling catheter was implanted in the internal carotid artery via a common carotid arteriotomy and preloaded with a 0.38-mm-diameter clot of 1.5, 3, or 6 cm length. After discontinuing anesthesia, the rat was returned to a home cage where it regained normal mobility, grooming, eating activity, and a stable recovery of MABP. One hour later, the clot was injected over a 10-s period and the rats were observed for 24 h. Clot injection produced a brief period of irritability, then 15-20 min of complete inactivity, followed by lethargic activity at 20-40 min, ipsilateral deviation of the head and neck at 1-2 h, and limb weakness and circling at 2-4 h. Neurologic deficits, elevated MABP, infarct volume, and increased hemisphere water content varied directly with clot size. Mortality after 6-cm clot injection (53%) was greater than that after 1.5-cm (10%) or 3-cm (20%) injection. Combined non-survivor groups had the greatest MABP, infarct volume, and water content. Among all groups, the pressor response correlated with infarct volume. The coefficient of variation of infarct volume with the 3-cm clot was less than that in published studies with the filament or standard clot models, and therefore may provide stronger statistical power for stroke translational studies. The more severe outcomes from the 6-cm clot model may be useful for the study of malignant stroke.

Feasibility and utility of a structured guide for cannabis tolerance breaks in young adults.

Objective: To explore the feasibility and utility of a tolerance break (T-Break) guide on young adults' cannabis use. Participants: Young adults aged 18-29 (n = 125) who were current cannabis users. Methods: Participants recruited through posters and listservs at various universities were offered the T-Break Guide-daily activities, advice, and encouragement-to help complete a 21-day cannabis break. Bivariate analyses examined associations between Guide use and follow-up measures. Results: Compared to non-Guide users, participants who used the Guide "a lot" were more likely to complete the 21-day abstinence break (84% vs. 57%), revise their personal definition of balance to mean less cannabis (84% vs. 62%), and plan a future break (32% vs. 11%). Conclusion: Use of this self-directed T-Break Guide may help young adults take a break from cannabis use and reduce future use. Further research using more rigorous designs to test the Guide's efficacy and assess longer-term maintenance of effects is needed.

What's New in Geriatric Acetabular Fractures.

The incidence of acetabular fractures in the geriatric population is growing, yet the optimal treatment algorithm remains a controversial topic among orthopaedic surgeons. This review highlights key studies published over the past 5 years on the outcomes of various treatment options for geriatric acetabular fractures. Topics include surgical timing, mortality and risk factors, nonoperative treatment, open reduction internal fixation, and acute total hip arthroplasty.

Literature Review of Subscapularis Tear, Associated injuries, and the Available Treatment Options.

The population of Hawai'i is uniquely connected to the Ocean and to open water sports. Shoulder injuries, particularly those to the rotator cuff, are among the most common injuries sustained to athletes participating in ocean sports such as surfing, paddling, and swimming. In addition, rotator cuff injuries increase in prevalence with advanced age. As a consequence, the number of patients in Hawai'i who present with an injury to the subscapularis tendon will continue to rise. However, limited research has been done to delineate the involvement of subscapularis injuries in this population. This article covers the anatomy and function of the subscapularis, the epidemiology and classification of tears in this tendon, and the management of tears. The anatomy section will cover innervation, vascular supply and insertional anatomy of the subscapularis tendon. The function of the subscapularis in regards to both stability and motion of the glenohumeral joint will be examined. The focus of the article will then shift to the tears of the subscapularis, starting with an in depth look at the epidemiology and classification of these tears. The article will then cover the different imaging modalities and their utility in regards to subscapularis tears. Finally, the operative and non-operative management and indications for each modality will be discussed in detail.

When Do Patients Return to Driving After Outpatient Foot and Ankle Surgery?

Counseling patients regarding when to return to driving following a foot and ankle procedure can be difficult, and 6 to 9 weeks is often recommended based on brake reaction times quoted in the literature. However, patients are ultimately responsible for the decision to drive. We aimed to determine when patients actually return to driving following outpatient foot and ankle surgery, what influences their decision, and whether any adverse events were experienced. Thirty-seven patients who underwent a right-sided foot and ankle procedure by a single orthopedic surgeon in an outpatient surgery center between September 2016 and December 2017 were recruited retrospectively for this study. Seventeen patients met inclusion criteria and participated in a telephone survey that inquired about their experiences and attitudes regarding return to driving following right-sided foot or ankle surgery. Of the patients surveyed, 100% drove a motor vehicle as their primary mode of transportation. Ten patients (59%) recalled having a discussion with the surgeon regarding when to resume driving, of which only 4 (23.5%) returned to driving at the suggested time they remembered. One patient (6%) returned to driving 2 weeks sooner, and 1 patient (6%) returned to driving 4 weeks later than recommended. No patient reported experiencing a driving-related adverse event. This study suggests that despite surgeons' recommendations, patients are returning to driving sooner than traditionally recommended. The surgeon's advice regarding when to return to driving may not be as influential as a patient's own self-assessment of their readiness to operate a vehicle after outpatient foot and ankle surgery.

Brain water as a function of age and weight in normal rats.

Rats are frequently used for studying water content of normal and injured brain, as well as changes in response to various osmotherapeutic regimens. Magnetic resonance imaging in humans has shown that brain water content declines with age as a result of progressive myelination and other processes. The purpose of this study was to quantify changes in brain water content during rat development and aging. Brain water content was measured by standard techniques in 129 normal male Sprague-Dawley rats that ranged in age (weight) from 13 to 149 days (18 to 759 g). Overall, the results demonstrated a decrease in water content from 85.59% to 76.56% with increasing age (weight). Nonlinear allometric functions relating brain water to age and weight were determined. These findings provide age-related context for prior rat studies of brain water, emphasize the importance of using similarly aged controls in studies of brain water, and indicate that age-related changes in brain water content are not specific to humans.

Effects of Volume Replacement for Urinary Losses from Mannitol Diuresis on Brain Water in Normal Rats.

BACKGROUND/OBJECTIVE: It is frequently recommended that urine output following perioperative mannitol administration be replaced 1:1 with an isotonic crystalloid solution. It is possible that this strategy could increase brain water by reducing the serum osmolality achieved with prior mannitol administration. Therefore, brain water content of rats treated with mannitol alone or mannitol plus normal saline (NS) was studied over a range of urinary replacement ratios. METHODS: Male Wister rats received mannitol 3.2 gm/100 gm infused over 45 min followed by hourly determinations of urine output (UO). Control animals received no additional therapy, whereas animals undergoing intervention received hourly replacement of their urinary losses with 0.9% NS in decreasing NS:UO ratios (1:1, 1:2, 1:3). Three hours after completion of the mannitol infusion, a final tally of UO was made. At that time in all animals, blood was obtained for determination of hemoglobin and electrolyte concentrations and plasma osmolality. Following that, the animals were sacrificed to determine brain water content. Additional groups underwent the same protocol but for 5 h with 1:1 urinary replacement, or received a volume of NS equal to that of the mannitol administered to all other control and intervention animals. RESULTS: 1:1 replacement of urinary loss with NS following mannitol administration was associated with brain water content indistinguishable from control animals receiving only a volume of NS equal to that of the mannitol administered to all other groups. Regression analysis demonstrated a decrease in the final brain water content of 0.67% (CI95 0.43-0.92, p < 0.001) per replacement level as NS:UO replacement ratios were decreased from 1:1 to 1:2 and, finally to 1:3. At the final NS:UO replacement ratio of 1:3, brain water content was indistinguishable from the control group receiving mannitol without NS replacement (p = 0.48) For 1:1 replacement following mannitol, brain water did not differ between experiments of 3 or 5 h duration (p = 0.52). CONCLUSIONS: In rats, NS replacement of UO 1:1 following mannitol administration leads to brain water content no different than if NS had been given in place of mannitol. Only when the NS:UO replacement ratio was 1:3, brain water was similar to that of control animals receiving mannitol alone. The recommendation to replace UO 1:1 with an equal volume of isotonic crystalloid following perioperative mannitol administration must recognize how this strategy could elevate brain water content compared to less vigorous replacement of UO.

The Use of Dried Bovine Hemoglobin and Plasma for Mass Rearing New World Screwworm.

The success of the Screwworm Eradication Program is due to continuous mass rearing and dispersal of large numbers of competitive sterile flies in the field. Spray-dried powders of whole bovine blood, chicken egg, and milk substitute constituted the nutritional components of the traditional artificial larval diet used for mass rearing New World Screwworm (NWS), Cochliomyia hominivorax (Coquerel), Diptera: Calliphoridae. However, due to shifting availability and increasing costs of diet ingredients, it is necessary to investigate alternative products for the diet. Recently, spray-dried whole bovine blood became unavailable for purchase in the quantities that the Screwworm Program requires and thus were obliged to purchase bovine blood subproducts. Previous research showed that bovine hemoglobin could be substituted for whole blood with good results in small trials. Here, we report results of NWS larval diets prepared with bovine blood subproducts, hemoglobin and plasma, in 20-liter trays used in mass rearing. Diets were prepared using three separate hemoglobin/plasma ratios. Though all three configurations of hemoglobin and plasma were successful in the larval diet, we found the diets containing 1.5% total plasma, as opposed to 0.5 and 1%, produced heavier larvae and pupae, and resulted in more pupae per unit of diet. Considering cost, we determined that the ideal ratio for the blood portion of the diet for mass rearing is 80% hemoglobin and 20% plasma.

Embryo Microinjection of Selenomethionine Reduces Hatchability and Modifies Oxidant Responsive Gene Expression in Zebrafish.

In previous studies we demonstrated that exposure to selenomethionine (SeMet) causes developmental toxicities in zebrafish (Danio rerio). The objectives of this study were to establish a dose-response relationship for developmental toxicities in zebrafish after embryo microinjection of Se (8, 16 or 32 µg/g dry mass of eggs) in the form of SeMet, and to investigate potential underlying mechanism(s) of SeMet-induced developmental toxicities. A dose-dependent increase in frequencies of mortality and total deformities, and reduced hatchability were observed in zebrafish exposed to excess Se via embryo microinjection. The egg Se concentration causing 20% mortality was then used to investigate transcript abundance of proteins involved in antioxidant protection and methylation. Excess Se exposure modified gene expression of oxidant-responsive transcription factors (nuclear factor erythroid 2-related factor nrf2a and nrf2b), and enzymes involved in cellular methylation (methionine adenosyltransferase mat1a and mat2ab) in zebrafish larvae. Notably, excess Se exposure up-regulated transcript abundance of aryl hydrocarbon receptor 2 (ahr2), a signalling pathway involved in the toxicity of dioxin-related compounds. Our findings suggest that oxidative stress or modification of methylation, or a combination of these mechanisms, might be responsible for Se-induced developmental toxicities in fishes.

Liquid-based growth of polymeric carbon nitride layers and their use in a mesostructured polymer solar cell with V(oc) exceeding 1 V.

Herein we report a general liquid-mediated pathway for the growth of continuous polymeric carbon nitride (C3N4) thin films. The deposition method consists of the use of supramolecular complexes that transform to the liquid state before direct thermal condensation into C3N4 solid films. The resulting films exhibit continuous porous C3N4 networks on various substrates. Moreover, the optical absorption can be easily tuned to cover the solar spectrum by the insertion of an additional molecule into the starting complex. The strength of the deposition method is demonstrated by the use of the C3N4 layer as the electron acceptor in a polymer solar cell that exhibits a remarkable open-circuit voltage exceeding 1 V. The easy, safe, and direct synthesis of carbon nitride in a continuous layered architecture on different functional substrates opens new possibilities for the fabrication of many energy-related devices.

Upconversion-agent induced improvement of g-C3N4 photocatalyst under visible light.

Herein, we report the use of upconversion agents to modify graphite carbon nitride (g-C3N4) by direct thermal condensation of a mixture of ErCl3·6H2O and the supramolecular precursor cyanuric acid-melamine. We show the enhancement of g-C3N4 photoactivity after Er(3+) doping by monitoring the photodegradation of Rhodamine B dye under visible light. The contribution of the upconversion agent is demonstrated by measurements using only a red laser. The Er(3+) doping alters both the electronic and the chemical properties of g-C3N4. The Er(3+) doping reduces emission intensity and lifetime, indicating the formation of new, nonradiative deactivation pathways, probably involving charge-transfer processes.

Comparison of equivolume, equiosmolar solutions of mannitol and hypertonic saline with or without furosemide on brain water content in normal rats.

BACKGROUND: Mannitol and hypertonic saline (HS) are used by clinicians to reduce brain water and intracranial pressure and have been evaluated in a variety of experimental and clinical protocols. Administering equivolume, equiosmolar solutions in healthy animals could help produce fundamental data on water translocation in uninjured tissue. Furthermore, the role of furosemide as an adjunct to osmotherapy remains unclear. METHODS: Two hundred twenty isoflurane-anesthetized rats were assigned randomly to receive equivolume normal saline, 4.2% HS (1,368 mOsm/L 25% mannitol (1,375 mOsm/L), normal saline plus furosemide (8 mg/kg), or 4.2% HS plus furosemide (8 mg/kg) over 45 min. Rats were killed at 1, 2, 3, and 5 h after completion of the primary infusion. Outcome measurements included body weight; urinary output; serum and urinary osmolarity and electrolytes; and brain, lung, skeletal muscle, and small bowel water content. RESULTS: In the mannitol group, the mean water content of brain tissue during the experiment was 78.0% (99.3% CI, 77.9-78.2%), compared to results from the normal saline (79.3% [99.3% CI, 79.1-79.5%]) and HS (78.8% [99.3% CI, 78.6-78.9%]) groups (P < 0.001), whereas HS plus furosemide yielded 78.0% (99.3% CI, 77.8-78.2%) (P = 0.917). After reaching a nadir at 1 h, brain water content increased at similar rates for mannitol (0.27%/h [99.3% CI, 0.14-0.40%/h]) and HS (0.27%/h [99.3% CI, 0.17-0.37%/h]) groups (P = 0.968). CONCLUSIONS: When compared to equivolume, equiosmolar administration of HS, mannitol reduced brain water content to a greater extent over the entire course of the 5-h experiment. When furosemide was added to HS, the brain-dehydrating effect could not be distinguished from that of mannitol.

Fetus in fetu in a neonate: report of a case.

Fetus in fetu (FIF) is a rare condition in which a malformed fetus resides in the body of its host. The presence of a well-formed vertebral column secures the diagnosis of FIF and differentiates this entity from a teratoma. Although more than 100 cases of FIF have been reported in the literature, the presence of a well-formed vertebral column is not documented in many cases. We herein report the case of a 19-day-old female who presented with a lump in the abdomen. Plain radiograph of the abdomen showed the presence of a well-formed vertebral column with long bones, and the results were confirmed with ultrasonogram and CT scans. Therefore, a preoperative diagnosis of FIF was made, and the mass was successfully excised. Upon opening the sac of the mass, a malformed anencephalic fetus was found.

Infarct volume after hyperacute infusion of hypertonic saline in a rat model of acute embolic stroke.

INTRODUCTION: Hypertonic saline (HS) can treat cerebral edema arising from a number of pathologic conditions. However, physicians are reluctant to use it during the first 24 h after stroke because of experimental evidence that it increases infarct volume when administered early after reperfusion. Here, we determined the effect of HS on infarct size in an embolic clot model without planned reperfusion. METHODS: A clot was injected into the internal carotid artery of male Wistar rats to reduce perfusion in the middle cerebral artery territory to less than 40 % of baseline, as monitored by laser-Doppler flowmetry. After 25 min, rats were randomized to receive 10 mL/kg of 7.5 % HS (50:50 chloride:acetate) or normal saline (NS) followed by a 0.5 mL/h infusion of the same solution for 22 h. RESULTS: Infarct volume was similar between NS and HS groups (in mm(3): cortex 102 ± 65 mm(3) vs. 93 ± 49 mm(3), p = 0.72; caudoputamenal complex 15 ± 9 mm(3) vs. 21 ± 14, p = 0.22; total hemisphere 119 ± 76 mm(3) vs. 114 ± 62, p = 0.88, respectively). Percent water content was unchanged in the infarcted hemisphere (NS 81.6 ± 1.5 %; HS 80.7 ± 1.3 %, p = 0.16), whereas the HS-treated contralateral hemisphere was significantly dehydrated (NS 79.4 ± 0.8 %; HS 77.5 ± 0.8 %, p < 0.01). CONCLUSIONS: HS reduced contralateral hemispheric water content but did not affect ipsilateral brain water content when compared to NS. Infarct volume was unaffected by HS administration at all evaluated locations.

Highly efficient single-layer polymer ambipolar light-emitting field-effect transistors.

Single-layer polymer light-emitting field-effect transistors (LEFETs) that yield EQEs of >8% and luminance efficiencies >28 cd A(-1) are demonstrated. These values are the highest reported for LEFETs and amongst the highest values for fluorescent OLEDs. Due to the electrostatics of the ambipolar LEFET channel, LEFETs provide an inherent advantage over OLEDs in terms of minimizing exciton-polaron quenching.

Dietary selenomethionine exposure in adult zebrafish alters swimming performance, energetics and the physiological stress response.

Selenomethionine (Se-Met) is the major form of organoselenium present in food. Early life stages of oviparous vertebrate species, especially fish, are highly susceptible to dietary selenium (Se) exposure; however less is known concerning effects in adults. The present study was designed to investigate behavioral and physiological consequences of dietary Se-Met exposure to adult zebrafish (Danio rerio). Adult fish were fed either control food (1.3µg Se/g, dry weight or dw) or food spiked with varying measured concentrations of Se (3.7, 9.6 and 26.6 µg Se/g, dw) in the form of Se-Met for 60 days at 5% body weight/day ration, and an additional 30-40 days with equal ration (2.5%) of control or Se-Met spiked foods and clean chironomids. At the end of the exposure period, critical swimming speed (Ucrit), oxygen consumption (MO(2)), cost of transport (COT), tail beat amplitude, tail beat frequency, and whole body cortisol, triglyceride and glycogen levels were determined. Significantly reduced Ucrit was observed in fish fed 3.7, 9.6 and 26.6 µg Se/g when compared to control fish. Although MO(2) of fish fed >3 µg Se/g was consistently greater than control fish, those values were not statistically significant. There was no difference in COT among different treatment groups. Tail beat amplitudes of fish fed >3 µg Se/g were lower than control fish, however tail beat frequencies were not altered. Fish fed 3.7, 9.6 and 26.6 µg Se/g had greater whole body triglycerides and glycogen levels than control fish. Fish fed the highest concentration of Se (26.6 µg Se/g) had elevated levels of whole body cortisol compared to control fish. Our results suggest that environmentally relevant dietary Se-Met exposure can alter both behavioral and physiological responses in adult fish, and such consequences could threaten fitness of adult fish in Se impacted aquatic ecosystems.

A stereoselective, Sm(II)-mediated approach to decorated cis-hydrindanes: synthetic studies on faurinone and pleuromutilin.

The cis-hydrindane motif is found in a number of natural products that display important biological activity. A flexible, stereoselective approach to the framework has been developed that features highly diastereoselective, SmI(2)-mediated cyclisations. The strategy has been exploited in the first synthesis of the proposed structure of faurinone and an approach to the skeleton of the antibacterial natural product, pleuromutilin.