Large‐Stroke Electrochemical Carbon Nanotube/Graphene Hybrid Yarn Muscles

Artificial muscles are reported in which reduced graphene oxide (rGO) is trapped in the helical corridors of a carbon nanotube (CNT) yarn. When electrochemically driven in aqueous electrolytes, these coiled CNT/rGO yarn muscles can contract by 8.1%, which is over six times that of the previous results for CNT yarn muscles driven in an inorganic electrolyte (1.3%). They can contract to provide a final stress of over 14 MPa, which is about 40 times that of natural muscles. The hybrid yarn muscle shows a unique catch state, in which 95% of the contraction is retained for 1000 s following charging and subsequent disconnection from the power supply. Hence, they are unlike thermal muscles and natural muscles, which need to consume energy to maintain contraction. Additionally, these muscles can be reversibly cycled while lifting heavy loads.     

DDAVP use during pregnancy: an analysis of its safety for mother and child

Synthetic 1-deamino-8-D-arginine-vasopressin (DDAVP) is used in the management of diabetes insipidus (DI). We conducted a systematic literature review of DDAVP use during pregnancy, with particular attention to its safety for both mother and infant. Studies were identified through Ovid MEDLINE from 1976 to July 1997 using the combined terms "desmopressin," "DDAVP," and "pregnancy". Review articles and published letters were also explored. One hundred one articles were retrieved, of which 20 met all the inclusion criteria. Included in the 20 articles were 53 cases with the use of DDAVP for the management of DI. The therapeutic daily dose of DDAVP was approximately 29 micrograms intranasally (range 7.5-100 micrograms), with adequate DI control observed. Three of 14 women with sufficient information developed preeclampsia, a nonsignificant difference from the expected rate of 5 percent (the Fisher exact test, 2-P = .08). The mode of delivery was defined for 22 cases, with 16 uneventful vaginal births, and six cesarean delivery. There was no evidence of a drug interaction among the five women who received both DDAVP and intravenous oxytocin. Information was available on 49 live births born to DI mothers on DDAVP. The mean gestational age at delivery was 37.4 weeks (SD 1.3 weeks), with an estimated mean birth weight of 2963.8 gm (range 2000-4420 gm). Forty-three offspring were reported as healthy (event rate 87.8 percent; 95 percent CI 77.2-95.3 percent). Of the remaining six infants, one developed DI at 18 months of age; a second was under 2500 gm at birth, but survived; the third developed hypotonia and failure to thrive at 21 months, two others had Down syndrome; and the sixth died of severe cardiac anomalies. Similar data were seen among the 41 infants whose mothers had used DDAVP throughout pregnancy. In conclusion, DDAVP use during pregnancy seems to be safe for both mother and child. Delivery does not seem to be augmented by its use, nor are there likely any associated adverse neonatal effects. A large database of DDAVP use during pregnancy is needed to confirm these findings.     

Measurements on a Dynamic A-B Phase Boundary in Superfluid 3He at Very Low Temperatures

We present preliminary measurements of the dynamics of a moving A-B phase interface in superfluid ³ He at temperatures below 0.2T _c We initially stabilise the interface at low temperatures with a shaped magnetic field. We can then move the interface in a controlled manner by applying small additional time-dependent fields. The interface is created inside a quasiparticle radiator consisting of a cylindrical chamber in weak thermal contact with the refrigerant. Vibrating wire resonators inside the radiator allow us to monitor the temperature of the superfluid and to infer the heat generated by the interface motion. When we oscillate the interface at low frequencies, we measure spectacular oscillatory swings of the liquid temperature arising from the enormous change in the low lying density of states as the volume of the A-phase superfluid is alternately compressed and expanded. We have also observed hysteresis in the transition as a function of magnetic field. In particular, we observe a small history-dependent super-magnetisation of the B-phase prior to A-phase nucleation in the experimental chamber. When the system is in the metastable super-magnetised state we are able to observe a higher nucleation probability of the A-phase when the cryostat is exposed to neutrons.     

Digital image processing-an object-oriented approach

This paper presents a class library dedicated to digital image processing which provides resources for essential digital image processing operations. Besides its practical value, the class library is used to teach both object-oriented software engineering methodology and digital image processing. The resulting module can be accessed from independent specialized applications through its public interface while its implementation details are perfectly encapsulated. First of all it is used as the inner part of an integrated environment designed for students and researchers in the field of digital image processing. This software component was built aiming for both portability and extendibility. It contains attributes and methods that allow for a wide range of digital image processing algorithms: point and geometric operations; filter, edge detection, segmentation and texture operations; and fast Fourier transforms, discrete cosine transforms, and wavelet and Gabor transformations. All these can be used for image enhancement, restoration, compression, analysis, and synthesis     

New aspects in the microstructure of YBCO melt-textured high-Tc superconductors

The microstructure and phase constitution of bulk textured YBCO samples prepared by the modified MTG method in the longitudinal temperature gradient have been investigated. We found the existence of an unusual phase between stacked platelets. Microanalysis shows that this phase may be characterized as Y-143. This phase forms ellipsoid-like particles with a typical size about 0.05–2 which can play the role of effective pinning centers. The reason for the phase formation is discussed. We assume that this phase exists commonly in melt-textured samples prepared in the temperature field gradient.     

Surgical anatomy for endoscopic subfascial division of perforating veins

PURPOSE: This study was undertaken to define the surgical anatomy of the medial perforating veins (PVs) of the leg and to provide information on how to gain access to all medial PVs from the superficial posterior compartment during a subfascial endoscopic procedure. METHODS: The venous anatomy of 40 limbs (from 23 cadavers) were studied. Medial PVs located between the ankle and the tibial tuberosity were dissected. None of the subjects had pathologic evidence of venous disease. Each PV's type (direct or indirect), size (< 1 mm, 1 to 2 mm, > 2 mm), location (distances from ankle [D1], and tibia [D2]), and accessibility from the superficial posterior compartment were recorded. RESULTS: Five hundred fifty-two PVs were identified (mean, 13.8; range, 7 to 22). Two hundred eighty-seven PVs (52%) directly connected the superficial with the deep systems, 228 (41%) were indirect muscle perforators, and 37 PVs (7%) were undetermined. One hundred thirty-seven PVs (25%) were > 2 mm. Sixty-three percent of PVs were accessible from the superficial posterior compartment. In the distal half of the leg, two groups of direct PVs could be identified (Cockett II: D1, 7 to 9 cm; Cockett III: D1, 10 to 12 cm). In the proximal half of the leg, paratibial direct PVs (D2 < or = 1 cm) were found clustered in three groups (D1, 18 to 22 cm; D1, 23 to 27 cm; D1, 28 to 32 cm). CONCLUSIONS: Our study confirmed the presence of the Cockett II and III PVs and three groups of proximal paratibial PVs, including the "24-cm" perforators. Two thirds of the medial direct PVs are accessible for endoscopic division from the superficial posterior compartment. To divide paratibial PVs, however, incision of the paratibial deep fascia is frequently required.     

User sensitive research in e-learning: exploring the role of individual user characteristics

The increasing need for active and accessible learning in the inclusive knowledge society drives the demand for e-learning that engages users much more effectively than ever before. In this context, it is crucial to conduct research that embraces innovation in user sensitive design, or else influential individual user differences may be overlooked. The objective of this paper is to explore the creation of successful e-learning systems that are able to increase users’ learning performance and enhance their personal learning experiences. The paper reports two converging and complimentary approaches, namely case studies and experimentation. First, case studies are used to explore the extent to which effective e-learning systems comply with eight specific factors. Of the eight, accessibility, individual differences and student modeling turn out to be the weakest points in current practice. Second, an empirical study investigates the influences of user individual user differences on users’ learning outcomes in an e-learning environment. The experiment found that individual differences in motivation to learn and expectations about e-learning significantly impacted users’ learning achievements. Third, based on these studies, improvements in research methodology are identified towards greater consideration of user sensitive research issues, thus enabling us to outline improved experimental procedures. Further experiment results should provide us with better insights into the arguments needed to carefully assess benefits of developing and involving a user model in an e-learning application. Consequently, evaluation and justification could now encompass both system performance as well as user performance.     

C-PSA: Constrained Pareto simulated annealing for constrained multi-objective optimization

In recent years, evolutionary algorithms (EAs) have been extensively developed and utilized to solve multi-objective optimization problems. However, some previous studies have shown that for certain problems, an approach which allows for non-greedy or uphill moves (unlike EAs), can be more beneficial. One such approach is simulated annealing (SA). SA is a proven heuristic for solving numerical optimization problems. But owing to its point-to-point nature of search, limited efforts has been made to explore its potential for solving multi-objective problems. The focus of the presented work is to develop a simulated annealing algorithm for constrained multi-objective problems. The performance of the proposed algorithm is reported on a number of difficult constrained benchmark problems. A comparison with other established multi-objective optimization algorithms, such as infeasibility driven evolutionary algorithm (IDEA), Non-dominated sorting genetic algorithm II (NSGA-II) and multi-objective Scatter search II (MOSS-II) has been included to highlight the benefits of the proposed approach.