Foam processing of polyethylene ionomers with supercritical CO2

Via a batch process, the foam processing of polyethylene-based ionomers having two different degree of the neutralization has been conducted using supercritical CO₂. The cellular structures obtained from various ranges of foaming temperature-CO₂ pressure were investigated by using field emission scanning electron microscopy. For comparison, the corresponding nano-composite also has been examined. The ionic cross-linked structure in the ionomer exhibited significant contribution to retard the cell growth and coalescence of cell, especially in ionomer having higher degree of the neutralization. For nano-composite foaming, experimentally, nano-clay particles led to an increase in cell density after foaming. However, the dispersed nano-clay particles did not act as nucleating sites for cell formation. The competitive phenomenon between the cell nucleation and the cell growth including the coalescence of cell was discussed in the light of the interfacial energy and the relaxation rate as revealed by the modified classical nucleation theory and rheological measurement, respectively.     

Global Monitoring of Large Concrete Structures Using Acoustic Emission and Ultrasonic Techniques: Case Study

Global monitoring of civil structures is a demanding challenge for engineers. Acoustic emission (AE) is one of the techniques that have the potential to inspect large volumes with transducers placed in strategic locations of the structure. In this paper, the AE technique is used to characterize the structural condition of a concrete bridge. The evaluation of AE activity leads to information about any specific part of the structure that requires attention. Consequently, more detailed examinations can be conducted once the target area is selected. In this case, wave propagation velocity was used as a means to evaluate, in more detail, the condition of the region indicated by the AE analysis.     

A novel view of the variational Bayesian clustering

We prove that the evaluation function of variational Bayesian (VB) clustering algorithms can be described as the log likelihood of given data minus the Kullback–Leibler (KL) divergence between the prior and the posterior of model parameters. In this novel formalism of VB, the evaluation functions can be explicitly interpreted as information criteria for model selection and the KL divergence imposes a heavy penalty on the posterior far from the prior. We derive the update process of the variational Bayesian clustering with finite mixture Student's t-distribution, taking the penalty term for the degree of freedoms into account.     

Myasthenia gravis presenting as isolated respiratory failure

We present 2 cases of idiopathic CD4+ T-lymphocytopenia (ICL) in elderly patients. Case 1, a 73-year-old man, with pneumonia had received several antibiotics with unsuccessful results at another hospital. On admission, his CD4+ T-lymphocyte count was 109/microl and Pneumocystis carinii was detected by bronchoalveolar lavage fluid staining. No evidence of human immunodeficiency virus (HIV) infection was found. Despite therapy, the patient died of respiratory failure. Case 2, a 72-year-old man, contracted severe pneumonia, and Hemophillus influenzae was believed to be the pathogen. On admission, his CD4+ T-lymphocyte count was 238/microl. No evidence of HIV infection was found. He received antibiotics and improved successfully. We suggest that ICL may currently be incubating in a number of elderly pneumonia patients.     

High-dose chemotherapy with autologous peripheral blood stem cell transfusion in the treatment of advanced testis cancer

Four patients with advanced testis cancer were treated by high-dose chemotherapy supporting by autologous peripheral blood stem cell transplantation. High-dose chemotherapy (carboplatin 250 mg/m2 or nedaplatin 200 mg/m2, etoposide 1,500 mg/m2, ifosphamide 7.5 g/m2 was given and peripheral blood stem cell transfusion was performed 72 hours after the last dose of chemotherapy. High-dose chemotherapy. was given followed by 1 or 2 cycles of pre high-dose therapy consisting of cisplatin 100 mg/m2 or carboplatin 500 mg/m2, etoposide 450 mg/m2, ifosphamide 6 g/m2. All 4 patients were evaluable. Three patients obtained a complete response and one showed a partial response. The partial responder was given RPLND. The RPLND specimen showed necrotic tissue.     

Synthesis of Indoles via Sigmatropic Rearrangements and Olefin Isomerization

Indoles are important heterocycles in pharmaceuticals and agrochemicals, and their atom-economical synthesis is needed. Herein, we describe the synthesis of indoles using sigmatropic rearrangements. The N-allylaniline was oxidized by environmentally benign hydrogen peroxide, and spontaneous [2,3]-Meisenheimer rearrangement gave N-allyloxyaniline. Subsequent treatment with a ruthenium catalyst afforded N-vinyloxyaniline, which underwent [3,3]-sigmatropic rearrangement to give indoles, expelling water as the only byproduct. The whole sequence is free of quantitative salt byproducts, thereby avoiding aqueous work up and cutting off the inorganic waste.     

Gas absorption by wavy falling liquid film formed on inner surface of vertical tubes

An experimental study on gas absorption into falling liquid film formed on inner surface of vertical tubes has been carried out in order to clarify fundamental characteristics of the gas absorption and enhancement by surface waves. The water supplied into the test tubes is periodically disturbed by fluctuating a silicon tube before the test section with a speaker and the wavy films absorb the oxygen filled in the tubes. Imposing the periodic disturbance enhances the gas absorption and the enhancement has a maximum at around 20–30 Hz, where the gas absorption is 20–30% higher. Mass transfer coefficients obtained with five tubes agree well with those obtained with single tube. Two-dimensional numerical simulations have also been conducted for gas absorption by wavy film and the enhancement mechanism of the gas absorption is discussed.     

One-step synthesis of magnetically recyclable Au/Co/Fe triple-layered core-shell nanoparticles as highly efficient catalysts for the hydrolytic dehydrogenation of ammonia borane

Magnetically recyclable Au/Co/Fe core-shell nanoparticles (NPs) have been successfully synthesized via a one-step in situ procedure. Transmission electron microscope (TEM), energy dispersive X-ray spectroscopic (EDS), and electron energy-loss spectroscopic (EELS) measurements revealed that the trimetallic Au/Co/Fe NPs have a triple-layered core-shell structure composed of a Au core, a Co-rich inter-layer, and a Fe-rich shell. The Au/Co/Fe core-shell NPs exhibit much higher catalytic activities for hydrolytic dehydrogenation of ammonia borane (NH₃BH₃, AB) than the monometallic (Au, Co, Fe) or bimetallic (AuCo, AuFe, CoFe) counterparts.      

Effects of endogenous endo-beta-1,4-glucanase on cellulose biosynthesis in Acetobacter xylinum ATCC23769

Endo-beta-1,4-glucanase (CMCax; EC 3.2.1.4) from Acetobacter xylinum ATCC23769 was expressed as a 6 x His-tagged fusion protein in Escherichia coli. The optimal temperature, pH, K(m) and V(max) of the purified His-tagged CMCax toward carboxymethyl cellulose were 50 degrees C, 4.5, 20 mg/ml and 37.2 microM/min, respectively. The number of recognition residues of cello-oligosaccharide by this enzyme were five (cellopentaose) or longer, and the stereochemical course of hydrolysis was of the inverting type. Addition of a small amount (1.5 mg/l) of His-tagged CMCax into a culture medium enhanced cellulose production 1.2-fold. CMCax overproduction in A. xylinum also enhanced the yield of cellulose production. Transmission electron microscopic analysis revealed that the cellulose ribbons secreted from the CMCax overproducing strain were dispersed compared with those from the wild type strain in the same manner as by carboxymethyl cellulose addition. These results could suggest that CMCax from A. xylinum influences in cellulose ribbon assembly, which is considered to be a rate-determined process in cellulose synthesis.     

Low-power wake-up receiver with subthreshold CMOS circuits for wireless sensor networks

We developed a wake-up receiver comprised of subthreshold CMOS circuits. The proposed receiver includes an envelope detector, a high-gain baseband amplifier, a clock and data recovery (CDR) circuit, and a wake-up signal recognition circuit. The drain nonlinearity in the subthreshold region effectively detects the baseband signal with a microwave carrier. The offset cancellation method with a biasing circuit operated by the subthreshold produces a high gain of more than 100 dB for the baseband amplifier. A pulse-width modulation (PWM) CDR drastically reduces the power consumption of the receiver. A 2.4-GHz detector, a high-gain amplifier and a PWM clock recovery circuit were designed and fabricated with 0.18-μm CMOS process with one poly and six metal layers. The fabricated detector and high-gain amplifier achieved a sensitivity of ?47.2 dBm while consuming only 6.8 μW from a 1.5 V supply. The fabricated clock recovery circuit operated successfully up to 500 kbps.