Cellulose nanofibrils as templates for the design of poly(l-lactide)-nucleating surfaces

The abilities of surface-grafted cellulose nanofibrils for the nucleation of poly(l-lactide) (PLLA) were investigated. Cellulose nanofibrils with a width of ∼3 nm were obtained from wood cellulose via the oxidation using 2,2,6,6-tetramethylpiperidiniyl-1-oxyl as a catalyst and successive mechanical treatment. The cellulose nanofibril surfaces were selectively modified with amine-terminated poly(ethylene glycol) chains, via simple ionic bonds. The PEG-grafted cellulose nanofibril/PLLA composite films were prepared using a solvent casting method with chloroform. The isothermal and non-isothermal crystallization kinetics of the PLLA in the composites was studied using differential scanning calorimetry and polarized optical microscopy. The PEG chains were densely immobilized on the surface of the cellulose nanofibril templates, which had extraordinarily large specific surface areas. As a result, the surface-PEG layers effectively increased the rate of crystallization of the PLLA in the composites. Because of the increased degree of crystallinity after the isothermal crystallization, the composites showed better heat resistance than neat PLLA.     

Lexicon-driven segmentation and recognition of handwritten character strings for Japanese address reading

This paper describes a handwritten character string recognition system for Japanese mail address reading on a very large vocabulary. The address phrases are recognized as a whole because there is no extra space between words. The lexicon contains 111,349 address phrases, which are stored in a trie structure. In recognition, the text line image is matched with the lexicon entries (phrases) to obtain reliable segmentation and retrieve valid address phrases. The paper first introduces some effective techniques for text line image preprocessing and presegmentation. In presegmentation, the text line image is separated into primitive segments by connected component analysis and touching pattern splitting based on contour shape analysis. In lexicon matching, consecutive segments are dynamically combined into candidate character patterns. An accurate character classifier is embedded in lexicon matching to select characters matched with a candidate pattern from a dynamic category set. A beam search strategy is used to control the lexicon matching so as to achieve real-time recognition. In experiments on 3,589 live mail images, the proposed method achieved correct rate of 83.68 percent while the error rate is less than 1 percent.     

The long-term effect of occlusal therapy on self-administered treatment outcomes of TMD

BACKGROUND: The proteins of halophilic archaea require high salt concentrations both for stability and for activity, whereas they denature at low ionic strength. The structural basis for this phenomenon is not yet well understood. The crystal structure of dihydrofolate reductase (DHFR) from Haloferax volcanii (hv-DHFR) reported here provides the third example of a structure of a protein from a halophilic organism. The enzyme is considered moderately halophilic, as it retains activity and secondary structure at monovalent salt concentrations as low as 0.5 M. RESULTS: The crystal structure of hv-DHFR has been determined at 2.6 A resolution and reveals the same overall fold as that of other DHFRs. The structure is in the apo state, with an open conformation of the active-site gully different from the open conformation seen in other DHFR structures. The unique feature of hv-DHFR is a shift of the alpha helix encompassing residues 46-51 and an accompanied altered conformation of the ensuing loop relative to other DHFRs. Analysis of the charge distribution, amino acid composition, packing and hydrogen-bonding pattern in hv-DHFR and its non-halophilic homologs has been performed. CONCLUSIONS: The moderately halophilic behavior of hv-DHFR is consistent with the lack of striking structural features expected to occur in extremely halophilic proteins. The most notable feature of halophilicity is the presence of clusters of non-interacting negatively charged residues. Such clusters are associated with unfavorable electrostatic energy at low salt concentrations, and may account for the instability of hv-DHFR at salt concentrations lower than 0.5 M. With respect to catalysis, the open conformation seen here is indicative of a conformational transition not reported previously. The impact of this conformation on function and/or halophilicity is unknown.     

Graft copolymerization of glass fiber and its application

Modified glass fibers, containing unsaturated hydrocarbon surface groups, were prepared by a hydrothermal treatment, with allylglycidylether in excess as reagent. Graft polymerization of the treated glass fiber with styrene and methylmethacrylate was carried out in sealed tubes, under nitrogen, using benzoyl peroxide (BPO) and cumene hydroperoxide (CHPO) as initiators. When BPO was used as the initiator, the grafting efficiency was extremely low, but the graft copolymerization behavior was similar to that of usual organic polymers. With CHPO, both grafting ratio and grafting efficiency were very high. Various properties of composite materials containing grafted glass cloth were studied. Flexural strength, flexural modulus, and interlaminar shear strength increased proportionally to the increase of the grafting ratio; the same values were decreased only in a small extent after the boiling test.     

An 8.1-ns Column-Access 1.6-Gb/s/pin DDR3 SDRAM With an 8:4 Multiplexed Data-Transfer Scheme

Three circuit techniques for an 8.1-ns column-access 1.6-Gb/s/pin 512-Mb DDR3 SDRAM using 90-nm dual-gate CMOS technology were developed. First, an 8:4 multiplexed data-transfer scheme, which operates in a quasi-4-bit prefetch mode, achieves a 3.17-ns reduction in column-access time, i.e., from 11.3 to 8.13 ns. Second, a dual-clock latency counter reduces standby power by 22% and cycle time from 1.7 to 1.2 ns. Third, a multiple-ODT-merged output buffer enables selection of five effective-resistance values Rtt (20, 30, 40, 60, and 120 Omega) without increasing I/O capacitance. Based on these techniques, 1.6-Gb/s/pin operation with a 1.36-V power supply and a column latency of 7 was accomplished     

1.8-V 800-Mb/s/pin DDR2 and 2.5-V 400-Mb/s/pin DDR1 compatibly designed 1Gb SDRAM with dual-clock input-latch scheme and hybrid multi-oxide output buffer

This paper describes three circuit techniques for a DDR1/DDR2-compatible chip architecture designed for both high-speed and high-density DRAMs: 1) a dual-clock input-latch scheme, which reduces the excessive timing margin for random input commands by using a pair of latch circuits controlled by dual-phase one-shot clock signals, achieves a 0.9-ns reduction in cycle time from 3.05 to 2.15 ns; 2) a hybrid multi-oxide output buffer reduces the area penalty of the output buffer caused by compatible chip design from 1.35% to 0.3%; and 3) a quasi-shielded distributed data transfer scheme enables a 2.6-ns reduction in access time to 10.25 ns in both 2-b and 4-b prefetch operations. By using these techniques, we developed a 175.3-mm/sup 2/ 1-Gb SDRAM that operates as an 800-Mb/s/pin DDR2 or 400-Mb/s/pin DDR1.     

Theoretical analysis of atomic-scale friction in frictional-force microscopy

We perform a theoretical analysis of frictional-force microscopy(FFM) images of a cleaved graphite surface. The Tomlinson model with a single-atom tip is powerful for reproducing experimental FFM images. A mapping relation between the tip atom position and the cantilever basal position obtained by a stable equilibrium condition, gives a clear explanation of the physical meaning of FFM image patterns. This revised version was published online in June 2006 with corrections to the Cover Date.     

Roles of a neuronal cell-surface molecule, neuropilin, in nerve fiber fasciculation and guidance

PURPOSE: To determine whether infiltrative lung, airway, or vascular disease can be differentiated as the cause of mosaic attenuation on thin-section computed tomographic (CT) scans of the lung. MATERIALS AND METHODS: Thin-section CT scans were reviewed in 70 patients examined at three institutions. A mosaic attenuation pattern and pathologic or clinical proof of a specific type of disease were demonstrated. Causes of the mosaic pattern included infiltrative lung disease (n = 37), airway disease (n = 22), and vascular disease (n = 11). Thin-section CT findings were assessed independently by two observers blinded to clinical findings. RESULTS: The type of disease was identified correctly at CT in 58 (83%) of 70 patients by observer 1 and 57 (81%) of 70 patients by observer 2. Infiltrative lung disease was diagnosed correctly by both observers in 34 (92%) of 37 cases. Observer 1 identified 21 (95%) of 22 cases of airway disease and three (27%) of 11 cases of vascular disease. Observer 2 identified 19 (86%) of 22 cases of airway disease and four (36%) of 11 cases of vascular disease. CONCLUSION: Infiltrative lung disease and airway disease may be differentiated reliably as the cause of mosaic attenuation on lung CT scans, whereas vascular disease is often misinterpreted as infiltrative lung disease or airway disease.