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At least 127 records · Page 7Linked to original sources
PubMed2006

Atomic layer deposition of tungsten(III) oxide thin films from W2(NMe2)6 and water: precursor-based control of oxidation state in the thin film material.

The atomic layer deposition of W2O3 films was demonstrated employing W2(NMe2)6 and water as precursors with substrate temperatures between 140 and 240 degrees C. At 180 degrees C, surface saturative growth was achieved with W2(NMe2)6 vapor pulse lengths of >/=2 s. The growth rate was about 1.4 A/cycle at substrate temperatures between 140 and 200 degrees C. Growth rates of 1.60 and 2.10 A/cycle were observed at 220 and 240 degrees C, respectively. In a series of films deposited at 180 degrees C, the film thicknesses varied linearly with the number of deposition cycles. Time-of-flight elastic recoil analyses demonstrated stoichiometric W2O3 films, with carbon, hydrogen, and nitrogen levels between 6.3 and 8.6, 11.9 and 14.2, and 4.6 and 5.0 at. %, respectively, at substrate temperatures of 160, 180, and 200 degrees C. The as-deposited films were amorphous. Atomic force microscopy showed root-mean-square surface roughnesses of 0.7 and 0.9 nm for films deposited at 180 and 200 degrees C, respectively. The resistivity of a film grown at 180 degrees C was 8500 microhm cm.

Journal Article↗
PubMed1984

Thin filament proteins and thin filament-linked regulation of vertebrate muscle contraction.

Recent developments in the field of myofibrillar proteins will be reviewed. Consideration will be given to the proteins that participate in the contractile process itself as well as to those involved in Ca-dependent regulation of striated (skeletal and cardiac) and smooth muscle. The relation of protein structure to function will be emphasized and the relation of various physiologically and histochemically defined fiber types to the proteins found in them will be discussed.

Actins↗
PubMed1994

[Harvesting thin and semi-thin skin from the scalp: risks and their prevention].

The complications of raising scalp grafts are dominated by the risks of haemorrhage and alopecia, which can be prevented by careful preparation of the donor site, perfect intraoperative coordination and close surveillance of epithelialisation. The authors report their experience in the Freyming-Merlebach burns unit, with particular emphasis on the value of this technique in children.

Adolescent↗
PubMed2002

[Influence of thinning on regeneration in a coastal pinus thunbergii forest].

A coastal forest planted nearby the sea can provide many shelter benefits for the coastal regions. It is ideally if the continuity of the shelter benefits could be preserved through reasonable management. Thinning and regeneration as the most important management techniques for plantations can help the continuity of the shelter benefits of the coastal forest. However, because of the peculiarities of coastal forest, i.e., the coastal plantation nearby the sea is vulnerable to disturbances (thinning as one kind of disturbance), the study on thinning and regeneration within a coastal forest is poorly understood. The purpose of this paper is to give a primary understanding in natural regeneration for the coastal Pinus thunbergii forest with different thinning rates after four growing seasons since thinning. The experiment was carried out at the middle of the shoreline along the Japan Sea, and the investigated sites consisted of four thinning treatments (control, 0% thinned, 20% thinned, 30% thinned and 50% thinned) in a coastal P. thunbergii forest. After thinning, the regenerated seedlings, soil water content, light condition (canopy openness or canopy density), wind regime, and litter depth and quantity were investigated for four growing seasons. The relationships between the regenerated seedlings and light condition, litter, wind profile and soil water content were examined. The results showed that thinning could improve the light condition on the forest floor, increase the exchange of airflow (wind speed) in the coastal forest stand, and ameliorate the water content of the forest soil. These factors accelerated the decomposition of litters, and provided necessary conditions for natural regeneration. The results of regeneration observation indicated that the most intensively thinned treatment (50% thinned with density of about 1500 stems.hm-2) could provide a better condition for regeneration during the four growing seasons. The density and growth of seedling (greater than 1 year) increased significantly with increasing thinning intensities, and the establishment of seedlings was obviously succeeded in the most intensively thinned treatment, but failed in less thinned treatments and understory. The thinned intensity of 50% did not induce wind damage to the coastal forest in the four years after thinning, and did not cause the loss of shelter functions of the coastal forest such as sand blocking, wind breaking and salt preventing etc.. On the contrary, it could provide the suitable conditions for natural regeneration of the pine coastal forest, or for the immigration of other species. Therefore, thinning as the silviculturally created openness is very important for the establishment of seedlings in the coastal forests, which provides a mechanism for the coastal forest from even aged stands dominated by P. thunbergii to stands containing multiple size classes and canopy layers.

China↗
PubMed1990

Calcium binds cooperatively to the regulatory sites of the cardiac thin filament.

To investigate the relationship between thin filament Ca2+ binding and activation of the MgATPase rate of myosin subfragment 1, native cardiac thin filaments were isolated and characterized. Direct measurements of 45Ca binding to the thin filament were consistent with non-cooperative binding to two high affinity sites (Ka 7.3 +/- 0.8 x 10(6) M-1) and either cooperative or non-cooperative binding to one low affinity site (Ka 4 +/- 2 x 10(5) M-1) per troponin at 25 degrees C, 30 mM ionic strength, pH 7.06. Addition of a low concentration of myosin subfragment 1 to the native thin filaments produced a Ca2+-regulated MgATPase activity with Kapp (2.5 +/- 1.3 x 10(5) M-1), matching the low affinity Ca2+ site. The MgATPase rate was cooperatively activated by Ca2+ (Hill coefficient 1.8). To determine whether Ca2+ binding to the low affinity sites was cooperative, native thin filament troponin was exchanged with troponin labeled on troponin C with 2-(4'-iodoacetamidanilo)naphthalene-6-sulfonic acid. From the Ca2+-sensitive fluorescence of this complex, Ca2+ binding was cooperative with a Hill coefficient of 1.7-2.0. Using the troponin-exchanged thin filaments, myosin subfragment 1 MgATPase rate activation was also cooperative and closely proportional to Ca2+ thin filament binding. Reconstitution of the thin filament from its components raised the Ca2+ affinity by a factor of 2 (compared with native thin filaments) and incorporation of fluorescently modified troponin raised the Ca2+ affinity by another factor of 2. Stoichiometrically reconstituted thin filaments produced non-cooperative MgATPase rate activation, contrasting with cooperative activation with native thin filaments, troponin-exchanged thin filaments and thin filaments reconstituted with a stoichiometric excess of troponin. The Ca2+-induced fluorescence transition of stoichiometrically reconstituted thin filaments was non-cooperative. These results suggest that Ca2+ binds cooperatively to the regulatory sites of the cardiac thin filament, even in the absence of myosin, and even though cardiac troponin C has only one Ca2+-specific binding site. A theoretical model for these observations is described and related to the experimental data. Well-known interactions between neighboring troponin-tropomyosin complexes are the proposed source of cooperativity and also influence the overall Ka. The data indicate that Ca2+ is four times more likely to elongate a sequence of troponin-tropomyosin units already binding Ca2+ than to bind to a site interior to a sequence of units without Ca2+.

Actins↗
PubMed2002

Ca(2+)- and s1-induced movement of troponin T on mutant thin filaments reconstituted with functionally deficient mutant tropomyosin.

The deletion mutant (D234Tm) of rabbit skeletal muscle alpha-tropomyosin, in which internal actin-binding pseudo-repeats 2, 3, and 4 are missing, inhibits the thin filament activated myosin-ATPase activity whether Ca(2+) ion is present or not [Landis et al. (1997) J. Biol. Chem. 272, 14051-14056]. Fluorescence resonance energy transfer (FRET) showed substantial changes in distances between Cys-60 or 250 of troponin T (TnT) and Gln-41 or Cys-374 of actin on wild-type thin filaments corresponding to three states of thin filaments [Kimura et al. (2002) J. Biochem. 132, 93-102]. Troponin T movement on mutant thin filaments reconstituted with D234Tm was compared with that on wild-type thin filaments to understand from which the functional deficiency of mutant thin filaments derives. The Ca(2+)-induced changes in distances between Cys-250 of TnT and Gln-41 or Cys-374 of F-actin were smaller on mutant thin filaments than on wild-type thin filaments. On the other hand, the distances between Cys-60 of TnT and Gln-41 or Cys-374 of F-actin on mutant thin filaments did not change at all regardless of whether Ca(2+) was present. Thus, FRET showed that the Ca(2+)-induced movement of TnT was severely impaired on mutant thin filaments. The rigor binding of myosin subfragment 1 (S1) increased the distances when the thin filaments were fully decorated with S1 in the presence and absence of Ca(2+). However, plots of the extent of S1-incuced movement of TnT against molar ratio of S1 to actin in the presence and absence of Ca(2+) showed that the S1-induced movement of TnT was also impaired on mutant thin filaments. The deficiency of TnT movement on mutant thin filaments causes the altered S1-induced movement of TnI, and mutant thin filaments consequently fail to activate the myosin-ATPase activity even in the presence of Ca(2+).

Actin Cytoskeleton↗