Stabilization of the Polar Structure and Giant Second-Order Nonlinear Response of Single Crystal γ-NaAs0.95Sb0.05Se2

The dearth of suitable materials significantly restricts the practical development of infrared (IR) laser systems with highly efficient and broadband tuning. Recently, γ-NaAsSe₂ is reported, and it exhibits a large nonlinear second-harmonic generation (SHG) coefficient of 590 pm V⁻¹ at 2 µm. However, the crystal growth of γ-NaAsSe₂ is challenging because it undergoes a phase transition to centrosymmetric δ-NaAsSe₂. Herein, the stabilization of non-centrosymmetric γ-NaAsSe₂ by doping the As site with Sb, which results in γ-NaAs_0.95Sb_0.05Se₂ is reported. The congruent melting behavior is confirmed by differential thermal analysis with a melting temperature of 450 °C and crystallization temperature of 415 °C. Single crystals with dimensions of 3 mm × 2 mm are successfully obtained via zone refining and the Bridgman method. The purification of the material plays a significant role in crystal growth and results in a bandgap of 1.78 eV and thermal conductivity of 0.79 Wm⁻¹ K⁻¹. The single-crystal SHG coefficient of γ-NaAs_0.95Sb_0.05Se₂ exhibits an enormous value of |d₁₁| = 648 ± 74 pm V⁻¹, which is comparable to that of γ-NaAsSe₂ and ≈20× larger than that of AgGaSe₂. The bandgap of γ-NaAs_0.95Sb_0.05Se₂ (1.78 eV) is similar to that of AgGaSe₂, thus rendering it highly attractive as a high-performing nonlinear optical material.     

Ruthenium cluster-like chalcogenide as a methanol tolerant cathode catalyst in air-breathing laminar flow fuel cells

This paper reports the incorporation of a cluster-like Ru_xSe_y as a methanol tolerant cathode catalyst in a laminar flow fuel cell. The effect on cell performance of several concentrations of methanol in the cathode stream was investigated for the Ru_xSe_y catalyst and compared to a conventional platinum catalyst. While the Pt catalyst exhibited up to ∼80% drop in power density, the Ru_xSe_y catalyst showed no decrease in performance when the cathode was exposed to methanol. At several methanol concentrations the Ru_xSe_y catalyst performed better than the Pt catalyst. This demonstration of a methanol tolerant catalyst in a laminar flow fuel cell opens up the way for further miniaturization of the cell design and simplification of its operation as the need for an electrolyte stream to prevent fuel crossover has been eliminated.     

Telerehabilitation using the Rutgers Master II glove following carpal tunnel release surgery: proof-of-concept.

Carpal tunnel syndrome is caused by the compression of the median nerve as it transits the carpal tunnel, with an incidence of about 1% of the population. If surgery is needed, the treatment involves decompression of the median nerve followed sometimes by musculoskeletal outpatient rehabilitation. This paper presents a proof-of-concept pilot clinical trial in which the Rutgers Masters II haptic glove was tested on five subjects, who were two weeks post-hand surgery. Subjects trained for 13 sessions, 30 min per session, three sessions per week, and had no conventional outpatient therapy. Computerized measures of performance showed group effects in hand mechanical energy (1200% for the virtual ball squeezing and DigiKey exercises and 600% for the power putty exercise). Improvement in their hand function was also observed (a 38% reduction in virtual pegboard errors, and 70% fewer virtual hand ball errors). Clinical strength measures showed increases in grip (by up to 150%) and key pinch (up to 46%) strength in three of the subjects, while two subjects had decreased strength following the study. However, all five subjects improved in their tip pinch strength of their affected hand (between 20%-267%). When asked whether they would recommend the virtual reality exercises to others, four subjects very strongly agreed and one strongly agreed that they would.     

Energetics of isolated hepatocyte swelling induced by sodium co-transported amino acids

Many of the serious, potentially fatal complications of hematopoietic stem cell transplantation have similarities to the multiple organ dysfunction syndrome (MODS) in critically ill nontransplant patients. One of these similarities is the alteration in the hemostatic system in such a way as to lower the levels of the naturally occurring anticoagulant proteins, especially antithrombin III. As in MODS, the outcome of transplant patients with these complications correlates with the degree of change in antithrombin III levels. Preliminary studies suggest that antithrombin III concentrate in pharmacologic doses along with intensive supportive care efforts can improve the clinical outcome of patients with these transplant-related complications. Further work to confirm these findings and, it is hoped, provide insight into the mechanism of action of antithrombin III in this setting is obviously warranted. Until such studies are completed, however, the preponderance of evidence suggests that when subjected to a risk-benefit analysis, patients in the early stages of transplant-related complications would be better off receiving antithrombin III supplementation than not.     

A hybrid experimental-numerical approach for load rating of reinforced concrete bridges with insufficient structural properties

This article presents a non-destructive approach for load rating of reinforced concrete bridges without structural plans. The approach is found on a hybrid method, which employs vibration and live load testing coupled with numerical simulation and model updating techniques, to converge on estimate of unknown structural parameters. The material properties of bridge and the amount of reinforcing steel for calculating the bending capacity of a bridge are determined through model updating results and nondestructive approaches. The updated model is then employed to determine load effects for calculating load rating factors, and these results are combined with live load test result to arrive at the bridge capacity, and ultimately the load rating. The method is validated by testing a skewed reinforced concrete slab bridge for load rating purposes. The bridge was instrumented with accelerometers and strain gages, and the responses of the bridge under vibration and quasi-static tests were measured. Results demonstrated that the proposed method is capable of determining the bridge capacity and load rating factor with good accuracy, and not only can be used for load rating of concrete bridges without structural information, but also can be useful in condition assessment of existing concrete bridge with available as-built information.