Use of Saturated Lightweight Sand to Improve the Mechanical and Microstructural Properties of UHPC with Fiber Alignment

This paper studied the influence of pre-saturated lightweight sand (LWS) on the mechanical and microstructural properties of UHPC cast with steel fiber alignment. The changes in hydration kinetics, porosity, nano-mechanical, and mechanical properties were studied. The LWS was used at 0–50% replacement volumes of total sand. Predominant fiber alignment was favored through a flow-induced casting method during casting of flexural prisms. Experiment results showed that the 28-d autogenous shrinkage was decreased from 450 to 275 μm/m with the LWS content increasing from 0 to 50%. The addition of 20% LWS led to maximum increases of 15%, 15%, and 20% in compressive strength, flexural strength, and T150, respectively, relative to UHPC made without any LWS. The use of 20% LWS combined with fiber alignment led to a synergistic effect of 45% and 40% on enhancing the flexural strength and T150, respectively, relative to UHPC without LWS and having random fiber orientation. The addition of LWS can enhance the cement hydration given the internal curing effect. Such enhanced cement hydration increased the percentage of high density and ultra-high density C–S–H from 50% to 75% and reduced the 28-d porosity from 12.5% to 9.5% with the use of 20% LWS. On the other hand, such internal curing can be overwhelmed by the introduced pores of LWS when excessive LWS was used, which led to significant increase in porosity of UHPC

For the Improvement of Mechanical and Microstructural Properties of UHPC with Fiber Alignment using Carbon Nanotube and Graphite Nanoplatelet

This paper investigates the influence of carbon nanotube (CNT) and graphite nanoplatelet (GNP) on the microstructure and mechanical characteristics of UHPC with steel fiber alignment. The content of CNT and GNP ranged from 0 to 0.3%, by mass of binder. Predominant fiber alignment was manipulated using a flow-induced casting method during UHPC placement. Experiment results indicated that the increase of CNT and GNP content from 0 to 0.3% led to 15%, 40%, and 50% improvement in compressive strength, flexural strength, and T150 (dissipated energy) of UHPC, respectively. Fiber alignment was shown to increase flexural strength and T150 by 30% and 35%, respectively, compared to UHPC with random finer orientation. Moreover, the synergy of nanomaterial and fiber alignment can lead to a maximum enhancement of 80% and 90% in flexural strength and T150, respectively. Microstructural analysis indicated that CNT and GNP can enhance cement hydration and enable the bridging of cracks at nano or microscale. Moreover, the use of CNT and GNP reduced the porosities of fiber-matrix interface from 6%-12.5% to 4%–7% and UHPC matrix from 5.5% to 4%. This consequently contributed to the significant improvement in mechanical properties of UHPC

Operative Treatment of Intra-articular Distal Radius Fractures Using the Small AO External Fixation Device

BackgroundA retrospective group study was done to evaluate the effect of the small AO external fixator in the management of acute intra-articular fractures of the distal radius.MethodsBetween January 1995 and December 1996, 70 consecutive patients with articular fractures of the distal radius were treated by closed reduction and external fixation with small AO external fixators. The mean age at the time of surgery was 58.9 years (range, 14–87 years). There were 58 Colles' Barton's fractures and 12 Smith's Barton's fractures. The follow-up period was 104 months (range, 92–118 months).ResultsAll fractures united in a mean of 5.8 weeks (range, 4–10 weeks). At the final follow-up, the average range of motion was 56.3 ± 11.6° in flexion, 58.6 ± 10.7° in extension, 21.5 ± 4.2° in ulnar deviation, 9.1 ± 2.9° in radial deviation, 71.5 ± 8.5° in pronation, and 67.3 ± 9.2° in supination. Compared with the normal side, the average grip force was 87 ± 6%. The overall clinical and functional outcomes, according to the scoring system of Gartland and Werley, showed that 22 patients (31.4%) had excellent results, 36 (51.4%) had good results, 9 (12.9%) had fair results, and 3 (4.3%) had poor results.ConclusionClosed reduction and external fixation with the small AO external fixator is useful and effective in the management of displaced comminuted articular fractures of the distal radius

Intra-articular injections of sodium hyaluronate (Hyalgan®) in osteoarthritis of the knee. a randomized, controlled, double-blind, multicenter trial in the asian population

<p>Abstract</p> <p>Background</p> <p>The efficacy and tolerability of 500-730 kDa sodium hyaluronate (Hyalgan^®) for treatment of osteoarthritis (OA) pain has been established in clinical trials, but few data are available in the Asian population. We conducted a randomized, double-blind, multicenter, placebo-controlled study to evaluate the efficacy and tolerability of this preparation in a Taiwanese population.</p> <p>Methods</p> <p>Two hundred patients with mild to moderate OA of the knee were randomized to receive five weekly intra-articular injections of sodium hyaluronate or placebo. The primary efficacy outcome was the change from baseline to Week 25 in patients' evaluation of pain using a 100-mm visual analog scale (VAS) during the 50-foot walking test. Additional outcomes included Western Ontario and McMaster Universities (WOMAC) scores, time on the 50-foot walking test, patient's and investigator's subjective assessment of effectiveness, acetaminophen consumption, and the amounts of synovial fluid.</p> <p>Results</p> <p>The Hyalgan^®treatment group showed a significantly greater improvement from baseline to Week 25 in VAS pain on the 50-foot walking test than the placebo group (p = 0.0020). The Hyalgan^®group revealed significant improvements from baseline to week 25 in WOMAC pain and function score than the placebo group (p = 0.005 and 0.0038, respectively) Other outcomes, such as time on the 50-foot walking test and subjective assessment of effectiveness, did not show any significant difference between groups. Both groups were safe and well tolerated.</p> <p>Conclusions</p> <p>The present study suggests that five weekly intra-articular injections of sodium hyaluronate are well tolerated, can provide sustained relief of pain, and can improve function in Asian patients with osteoarthritis of the knee.</p> <p>Level of Evidence</p> <p>Therapeutic study, Level I-1a (randomized controlled trial with a significant difference).</p> <p>Trial registration</p> <p>ClinicalTrials.gov Identifier: <a href="http://www.clinicaltrials.gov/ct2/show/NCT01319461">NCT01319461</a></p

Synthesis of microporous silica nanoparticles to study water phase transitions by vibrational spectroscopy

Silica can take many forms, and its interaction with water can change dramatically at the interface. Silica based systems offer a rich tapestry to probe the confinement of water as size and volume can be controlled by various templating strategies and synthetic procedures. To this end, microporous silica nanoparticles have been developed by a reverse microemulsion method utilizing zinc nanoclusters encapsulated in hydroxyl-terminated polyamidoamine (PAMAM-OH) dendrimers as a soft template. These nanoparticles were made tunable within the outer diameter range of 20-50 nm with a core mesopore of 2-15 nm. Synthesized nanoparticles were used to study the effects of surface area and microporous volumes on the vibrational spectroscopy of water. These spectra reveal contributions from bulk interfacial/interparticle water, ice-like surface water, liquid-like water, and hydrated silica surfaces suggesting that microporous silica nanoparticles allow a way to probe silica water interactions at the molecular scale

A backward evolution model for infrared surveys: the role of AGN- and Color-L_TIR distributions

Empirical "backward" galaxy evolution models for infrared bright galaxies are constrained using multi-band infrared surveys. We developed a new Monte-Carlo algorithm for this task, implementing luminosity dependent distribution functions for the galaxies' infrared spectral energy distributions (SEDs) and for the AGN contribution, allowing for evolution of these quantities. The adopted SEDs take into account the contributions of both starbursts and AGN to the infrared emission, for the first time in a coherent treatment rather than invoking separate AGN and star-forming populations. In the first part of the paper we consider the quantification of the AGN contribution for local universe galaxies, as a function of total infrared luminosity. It is made using a large sample of LIRGs and ULIRGs for which mid-infrared spectra are available in the Spitzer archive. In the second part we present the model. Our best-fit model adopts very strong luminosity evolution, $L=L_0(1+z)^{3.4}$, up to $z=2.3$, and density evolution, $\rho=\rho_0(1+z)^2$, up to $z=1$, for the population of infrared galaxies. At higher $z$, the evolution rates drop as $(1+z)^{-1}$ and $(1+z)^{-1.5}$ respectively. To reproduce mid-infrared to submillimeter number counts and redshift distributions, it is necessary to introduce both an evolution in the AGN contribution and an evolution in the luminosity-temperature relation. Our models are in plausible agreement with current photometry-based estimates of the typical AGN contribution as a function of mid-infrared flux, and well placed to be compared to upcoming Spitzer spectroscopic results. As an example of future applications, we use our best-fitting model to make predictions for surveys with Herschel.Comment: Model available at: (http://www.physics.ubc.ca/~valiante/model) ApJ accepte