Origin of stress and birefringence generation at hot-stretching of poly(methyl methacrylate) containing low-molecular-weight compound

The simultaneous measurements of stress and birefringence during hot-stretching, and after the cessation of stretching, were performed using a miscible blend of poly(methyl methacrylate) (PMMA) and 10 wt% of 4-cyano-4′-pentylbiphenyl (which is commonly known as 5CB). The birefringence of the blend exhibited anomalous behavior during stretching, that is, it initially decreased, then rapidly increased to a positive value. A concave curve with a minimum birefringence was prominent at low temperatures, during which PMMA determined birefringence. After passing the yield point, which corresponded to the minimum birefringence, the birefringence increased in proportion to the applied stress. That is to say, the stress-optical coefficient remained constant. In this region, the 5CB molecules oriented themselves with the PMMA chains, that is, there was nematic interaction. After stretching ceased, the stress initially decreased rapidly; during this period, the stress-optical coefficient was determined mainly by the deformation of PMMA, that is, glassy component. Subsequently, the orientation relaxation of 5CB, which occurred with the orientation relaxation of PMMA chains in the stage with a long time region, determined the birefringence. These results demonstrated that nematic interaction does not occur when inelastic deformation is governed.     

Synthesis of highly crystalline hexagonal cesium tungsten bronze nanoparticles by flame-assisted spray pyrolysis

Highly crystalline and hexagonal single-phase cesium tungsten bronze (Cs_0.32WO₃) nanoparticles were successfully synthesized by a flame-assisted spray pyrolysis followed by annealing under a reducing gas atmosphere. The resulting Cs_0.32WO₃ nanoparticles featured a pure hexagonal Cs_0.32WO₃ phase with a high crystallinity and homogeneous chemical composition. Unlike conventional methods, the proposed process in this paper has several advantages, including a short reaction time and the ability to yield products with high purity and good energy efficiency. Furthermore, the Cs_0.32WO₃ nanoparticles produced in this research showed a remarkable near-infrared shielding ability with a 97.7% cut-off at 1500?nm.     

Flexible ultraviolet detector with robust ZnO nanoparticle nanoassemblies on catechol-functionalized polysiloxane nanofilms

As a result of the vast Young's moduli difference between an inorganic semiconducting channel and flexible substrates, flexible optoelectronic devices readily lose their functionality through material delamination and local fracturing, which lead to short-circuiting of devices. For this study, we synthesized a catechol-containing polysiloxane (CFPS) adhesive and applied it to ZnO nanoparticle (NP) assembly on plastic substrates for flexible UV detector applications. The 30 nm thick CFPS adhesive can anchor 70 nm thick ZnO NPs strongly through a coordination bond, thereby forming an ultra-stable ZnO NP channel layer. A peeling test of ZnO NP layer was conducted using transparent tape (Scotch®; 3 M Inc.). The ZnO NPs were firmly immobilized, reflecting the outstanding mechanical stability of CFPS adhesives. A UV detector also exhibited stable photo-response performance even after a thousand iterations of bending with 3 mm curvature radii. The result indicates the polycyclosiloxane-based flexible device as promising for wearable detector applications.     

Clinical evaluation of a reagent for detection of DNA of Mycobacterium tuberculosis complex using the ligase chain reaction (LCR) method

We evaluated the clinical efficacy of LCR MTB, a reagent developed by Abbott in the USA, in the full automatic ligase chain reaction (LCR) for detection of DNA of M. tuberculosis complex using a thermostable ligase. Using 458 samples isolated from patients with tuberculosis, LCR was compared with a smear method and with a culture method, and was also compared with two other methods of gene amplification, MTD and Amplicor, using 340 and 200 of the 458 samples, respectively. The LCR method detected M. tuberculosis in 49.8% (228/458) of the samples, and was superior to the smear method (31.9%, 146/458) and the culture method (39.1%, 179/458) in sensitivity. The LCR method was also superior to the MTD and Amplicor methods; sensitivity were 37.9% (129/340) for MTD vs. 47.6% (162/340) for LCR, and 56.5% (113/200) for Amplicor vs. 59.5% (119/200) for LCR. These favorable results and the convenience of the LCR method, which enables rapid detection of target genes with a high degree of sensitivity, strongly suggest that LCR MTB is useful as a reagent for detection of M. tuberculosis using nucleic acid amplification.     

Site-directed mutagenesis of the putative active site residues of 3C proteinase of coxsackievirus B3: evidence of a functional relationship with trypsin-like serine proteinases

Picornavirus 3C proteinases (3C^pro) are cysteine proteinasesbut recent sequence analyses have shown that they are relatedto trypsin-like serine proteinases. Two models of 3C^pro structurehave been presented. Both models indicate that residues His40and Cysl47 are members of the catalytic triad but the modelsdiffer in the designation of the third member of the catalytictriad, which is assigned as either Glu71 or Asp85. To test theimportance of these four residues in the catalytic activityof 3C^pro of coxsackievirus B3, a member of the enterovirus subgroupof the picornavirus family, single amino acid substitutionswere introduced at each of the four sites. All of these mutationsresulted in the reduction or inactivation of autocatalytic cleavageof the 3C precursor protein expressed in Escherichia coli, suggestingthat all of these residues are essential for the proteolyticreaction. The substitution of Cysl47 with Ala abolished 3C^proactivity while the mutant in which Cysl47 was replaced withSer retained reduced proteolytic activity both in cis and intrans. Our results strongly support the proposal that Cysl47of 3C^pro functions as a nucleophile analogous to Serl95 of trypsin-likeserine proteinases.     

A static voltage fluctuation compensator for AC electric railway using self-commutated inverters

In this paper, the authors describe the basic configuration of an RPC (Railway Static Power Conditioner), its compensation principles and successful test results (using a small model of RPC). An ac electric railway is placed under a rapidly changing single-phase load. To avoid a voltage fluctuation under single-phase loads, electric power is received from a large source. At a feeding substation, three-phase electric power is transformed into two kinds of directional single-phase feeding electric power. The authors have already proposed a static voltage compensator for the ac electric railway, called “RPC.” The RPC links a pair of feeding circuits, using two self-commutated inverters. At the substation, the RPC accommodates an active power in the directional pair of feeding circuits to balance three-phase power, and possess a reactive power to regulate a three-phase voltage fluctuation. At a sectioning post, it can compensate for voltage drop using reactive power. It can also act as an active filter to compensate for harmonics. The authors have made a small model (220 V, 20 kVA) of the RPC, and report on the test results obtained using this small model under various conditions. The results indicate that the RPC can accommodate single phase loads, such as transformers and thyristors, can handle an exciter rush current from a transformer, can compensate for harmonics, and so on.     

Imaging with reduced holographic data-an application of the ARmodel to a multifrequency hologram

An application of the AR (autoregression) model in the scheme of the maximum entropy method to a multifrequency hologram of few frequency elements is presented in order to reconstruct an image of high resolution and quality. A direct extrapolation of the frequency array components of the hologram by the AR model is shown to be effective and stable, i.e., monotonically sensitive to the order of the model