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This study aimed to demonstrate that the simple tracing test (STT) is useful for assessing the hand dexterity in patients with cervical spondylotic myelopathy (CSM) by comparing STT scores between healthy volunteers and CSM patients. This study included 25 CSM patients and 38 healthy volunteers. In the STT, the participants traced a sine wave displayed on a tablet device at a comfortable pace, and the tracing accuracy, changes in the total sum of pen pressures, and tracing duration were assessed. Data were analyzed using an artificial neural networks (ANN) model to obtain STT scores. All participants were evaluated using the subsection for the upper extremity function of the Japanese Orthopaedic Association (JOA) scoring system for cervical myelopathy (JOA subscore for upper extremity function) and the grip and release test (GRT). The results were compared with the STT scores. The mean STT scores were 24.4 ± 32.8 in the CSM patients and 84.9 ± 31.3 in the healthy volunteers, showing a significant difference. The STT scores showed highly positive correlations with both the JOA subscore for upper extremity function (r = 0.66; P r = 0.74; P

BACKGROUND AND OBJECTIVE: Proprioceptive information from muscle receptors is important in force control and disturbed sensation due to fatigue may reduce the precision of force control. The aim of this study was to clarify the relationship between force sensation and force control ability in knee extensor muscles during fatigue. METHODS: Eighteen healthy young volunteers participated in this study. Force matching tasks with and without feedback were performed immediately before and after the fatigue protocol consisting of 20 s isometric contractions. The target force was 10% and 30% of the maximal voluntary contraction force in the pre-fatigue protocol. The accuracy of force control ability was estimated by the root mean square error (RMS error) and average difference (average error) between the target and output force. Surface electromyograms were recorded simultaneously from the quadriceps. RESULTS:In the 30% task, there was a significant interaction effect of fatigue and feedback condition in RMS error and average error. RMS error and average error were degenerated significantly by fatigue in the feedback removal condition, but not in the feedback condition. Though the activation of quadriceps was increased by fatigue, increase of muscle activation was lower in the feedback removal condition than that in the feedback conditions. CONCLUSION: Since participants controlled their force output depending on the force sensation in the feedback removal condition, these results indicate that the decline in force sensation may be a significant factor in the decreases of accuracy in force output during fatigue.

This study evaluated the effect of foot progression angle on the reduction in knee adduction moment caused by a lateral wedged insole during walking. Twenty healthy, young volunteers walked 10 m at their comfortable velocity wearing a lateral wedged insole or control flat insole in 3 foot progression angle conditions: natural, toe-out, and toe-in. A 3-dimensional rigid link model was used to calculate the external knee adduction moment, the moment arm of ground reaction force to knee joint center, and the reduction ratio of knee adduction moment and moment arm. The result indicated that the toe-out condition and lateral wedged insole decreased the knee adduction moment in the whole stance phase. The reduction ratio of the knee adduction moment and the moment arm exhibited a close relationship. Lateral wedged insoles decreased the knee adduction moment in various foot progression angle conditions due to decrease of the moment arm of the ground reaction force. Moreover, the knee adduction moment during the toe-out gait with lateral wedged insole was the smallest due to the synergistic effect of the lateral wedged insole and foot progression angle. Lateral wedged insoles may be a valid intervention for patients with knee osteoarthritis regardless of the foot progression angle.

The aim of this study was to examine the dexterity of both lower extremities in patients with stroke. Twenty patients with stroke and 20 age-matched control subjects participated in this study. To determine the dexterity of the lower extremities, we examined the ability to control muscle force during submaximal contractions in the knee extensor muscles using a force tracking task. The root mean square errors were calculated from the difference between the target and response force. The root mean square error was significantly greater in the affected limb of patients with stroke compared with those of the unaffected limb and the control subjects, and in the unaffected limb compared with that of the control subjects. Furthermore, the root mean square error of the affected limb was related significantly to motor function as determined by Fugl-Myer assessment. These results demonstrate impairment of the dexterity of both the affected and the unaffected lower extremities in patients with stroke.

The purpose of this study was to determine whether a lateral wedge insole reduces the external knee adduction moment during slope walking. Twenty young, healthy subjects participated in this study. Subjects walked up and down a slope using 2 different insoles: a control flat insole and a 7° lateral wedge insole. A three-dimensional motion analysis system and force plate were used to examine the knee adduction moment, the ankle valgus moment, and the moment arm of the ground reaction force to the knee joint center in the frontal plane. The lateral wedge insole significantly decreased the moment arm of the ground reaction force, resulting in a reduction of the knee adduction moment during slope walking, similar to level walking. The reduction ratio of knee adduction moment by the lateral wedge insole during the early stance of up-slope walking was larger than that of level walking. Conversely, the lateral wedge insole increased the ankle valgus moment during slope walking, especially during the early stance phase of up-slope walking. Clinicians should examine the utilization of a lateral wedge insole for knee osteoarthritis patients who perform inclined walking during daily activity, in consideration of the load on the ankle joint.

Changes of weight-average molecular weights (Mw) and the molecular weight distributions in terms of weight fraction (gw) were evaluated in the course of sonication for three nucleic acids in different conformations by the gel permeation chromatography/low angle laser light scattering (GPC/LALLS) method. High Mw samples used were single-stranded poly(uridylic acid), (U)n, double-stranded DNA, and triple-stranded poly(adenylic acid)·2poly(inosinic acid), (A)n·2(I)n, in 0.2−0.1 M NaCl at 0 °C. The experimental gw vs M curves were computer-simulated for different chain-scission mechanisms: (1) random, (2) midpoint, (3) Gaussian, (4) classical partially random, and (5) newly proposed partially random scission models. In comparison with the GPC/LALLS data, the middle portion of each single- or multiple-stranded chain was sheared randomly, whereas the adjacent end portions of the chain resisted sonic scission. The Mw value of each intact end portion was 1.0 × 105 for (U)n, 1.5 × 105 for DNA, and 1.7 × 105 for (...

The expression of the steady‐state value of electric dichroism (ED), over the entire electric field strength, for semistiff linear polymers with an electric polarizability along the chain has been derived by a normal mode approximation on the basis of the Brownian dynamics. Only a flexibility parameter, L/P defined as the contour length L to the persistence length P, is introduced into the expression without any assumption of the configuration. Our ED theory predicts that, with the increase in an L/P value, the steady state value is decreased over a low‐to‐medium field strength range but remains to be unchanged at infinitely high fields. The expression of the ED relaxation after the removal of an electric field is also derived, when the field strength is low. The off‐field relaxation decays multiexponentially not only due to rotational diffusion but also due to bending diffusion. The contribution of the bending to the decay amplitude is increased with increasing L/P. The flexibility strongly affects the t...

Sonication, Fractionation, and Molecular Weight Distribution of Alternating Polydeoxyribonucleotides: Poly(dG-dC) · Poly(dG-dC) and Poly(dA-dT) · Poly(dA-dT)

That reversing-pulse electric birefringence (RPEB) is an important technique in the study of microspheres was demonstrated with two polystyrene latexes with particle diameters of 430 and 81 nm and a styrene-glycidyl methacrylate copolymer latex with a diameter of 48 nm. RPEB signals were measured at 7°C and at a wavelength of 633 nm in the low electric field region in the presence of and in the absence of added salts (Na + or Ca 2+ ions). The instrument, measurements, and analysis of RPEB signals were described in detail. Well-defined signals were observed for all samples that are electron-microscopically spherical and uniform in the dry state. The particles, dispersed in aqueous media, probably form a solution phase on the outer layer of the spherical core. The charged sulfate groups at the polymeric chain terminal behave as the polyelectrolyte in this solution phase, giving rise to the electro-optic effect. The sign of birefringence is either positive or negative, reflecting a subtle difference in the electric and optical properties of the solution phase. The field-off relaxation time was evaluated from the decay curve of the RPEB signal, and the hydrodynamic diameters of the spherical particles were estimated.

Determination of Molecular Weight Distribution and Spectroscopic and Viscometric Properties of Sonicated Triple-Stranded Polyribonucleotides

The ultrasonic scission was studied for deoxyribonucleic acid (DNA) and five polyribonucleotide duplexes; three antiparallel-stranded helices (Poly(G)·Poly(C), Poly(A)·Poly(U), Poly(I)·Poly(C)) and two parallel-stranded helices (Poly(C)·Poly(C+) and Poly(A)·Poly(A+)). The sonication was carried out in 0.1—0.2 M NaCl solutions at 0°C and 200 watts for totally 20 minutes under helium gas atmosphere. The sonicated sample was fractionated by successive precipitation with acetone as the precipitant. For each duplex, several fractions were obtained in large quantities. The weight-average molecular weight Mw, the degree of polydispersity Mw/Mn, and the molecular weight distribution were determined for unsonicated, sonicated, and fractionated samples by the gel-permeation-chromatography/low-angle-laser-light-scattering method. The Mw values were reduced to a limit of 105 and the Mw/Mn values were narrowed to a 2—1.5 range by sonication. These values were further refined by fractionation. The molecular weight distribution profiles of well-defined fractions could be fitted by the logarithmic-normal function. The relationship between intrinsic viscosity and Mw was evaluated for each duplex. The result showed that the rigidity or flexibility of polymer chain depends on the molecular weight of fractionated samples and the kind of duplex examined.

In order to ascertain the non-Kerr-law behavior of a high molecular weight (M r =4.4×10 6 ) calf thymus DNA (hDNA), the steady-state electric birefringence (EB) at 535 nm and electric dichrosim (ED) at 260 nm were measured in aqueous solutions at 7 o C in a range of applied electric field (E) up to 10 kV/cm, with emphasis on the effect of counterions on the field strength dependence

The circular dichroic (CD) spectra of calf thymus deoxyribonucleic acid (hDNA) and the sonicated fragment (sDNA) with weight-average molecular weights of 580×104 and 14.2×104, respectively, were measured in the 220–320 nm wavelength region at 15°C in water-alcohol mixed solvents with an ionic strength of 0.4×10−3. The effect of ionic valence on CD spectra was examined with sodium or magnesium ions as the counterion and NaH2PO4/Na2HPO4 or Mg(CH3COO)2/CH3COOH as the buffer reagent. The CD spectra of both hDNA and sDNA with the Na+ counterion showed a B-form pattern in 0–70 vol% ethanol and transformed to an A-form profile in 72–90 vol%, the spectral change of hDNA being more cooperative than that of sDNA. Trifluoroethanol (TFE) induced changes in the CD spectra of sDNA as ethanol. In the case of the Mg2+ counterion, the CD spectra of h- and sDNA revealed the B-form pattern between 0 and 40% ethanol. A further addition of ethanol induced another spectral change, but fibrous precipitates appeared above 56% ethanol. From circular dichroic point of view, both hDNA and sDNA behave identically toward counterion, ethanol and TFE, their secondary structure probably remaining much the same.

Adsorption of native and heat-denatured calf thymus DNA (Mw = 2.5 × 105 and 4.5 × 106) and poly(cytidylic acid) · poly(inosinic acid) ((C)n · (I)n, Mw = 1.5 × 105, and 7.7 × 105) duplex onto the negatively charged poly(styrene) latex was examined at 4°C with emphasis on the effect of the molecular chain length, the species of added salts (NaCl, CaCl2, and MgCl2), and their ionic strengths ((1–10) × 10−3). The amount of adsorbed nucleic acids was determined photometrically from teh difference in the concentrations before and after mixing with the latex (average diameter, 471 nm; surface charge density, −3.52 μC/cm2). For native DNA, the higher the molecular weights and ionic strengths were, the more was adsorbed, the effect of the added ions being Mg2+ > Ca2+ ⩾ Na+. For denaturated DNA, the adsorption behavior was qualitatively the same but the adsorbed amount was less. These trends were reversed for (C)n · (l)n, but the effect of added ions remained the same as that for DNA. The divalent cations play a role of a binder between two types of negative charges on nucleic acids and on latex.

By irradiating ultrasonic wave (20 kHz).to calf thymus deoxyribonucleic acid (DNA) in aqueous solution (2 mg ml−1 containing 0.2 M NaCl) at 0°C, the molecular weight (Mw) was degraded from 8×106 to ca. 2×105 without any noticeable denaturation. The dependence of the molecular weight of sonicated DNA on the irradiation intensity was examined by varying ultrasonic energy levels. The molecular weights were remarkably decreased with the increase in ultrasonic power from 25 to 105 W, and reached a steady value (Mw=2.4×105) at 100—200 W.

Four sonicated calf thymus deoxyribonucleic acid (DNA).samples irradiated at different energies, whose molecular weights Mw were 5.7×105, 3.4×105, 2.4×105, and 2.4×105, respectively, as described in the preceding paper, were fractionated in 0.2 M NaCl aqueous solutions by the successive precipitation method with acetone as the precipitant. Each sample was separated into four fractions, each of which was dissolved in 1 mM NaCl and freeze-dried for storage. The molecular weight and molecular weight distribution were determined by means of intrinsic viscosity (25°C), GPC (20°C), and gel electrophoresis (0°C), and compared with those of unfractionated samples. The molecular weight of each fractionated DNA sample was found to be in the range between 0.7×105 and 7×105, while the degree of polydispersity in terms of Mw/Mn was found to be between 1.06 and 1.77, any of which is narrower than the values of the corresponding unfractionated sample. The hyperchromicity of each fractionated sample was estimated from the melting curve. It was always larger than 34%, which indicates that the double-stranded helical structure was maintained in the process of fractionation.

To clarify the electric field orientation of rodlike DNA and to correctly estimate the limiting high-field value, we measured the electric birefringence over a wide range of field strength up to 22.4 kV/cm at 7 o C and 535 nm in two aqueous solutions containing 0.2 and 1.0 mM Tris/HCl/NaCl (Tris=tris(hydroxymethyl)aminoethane). The dependence of the steady-state optical phase retardation δ on field strength E was examined with a particular emphasis on the extremely low-field (E

The light scattering and viscosity measurements were carried out at 25°C in 0.2 M NaCl solutions for 14 fractionated low molecular weight DNA (sDNA) samples, which were prepared by the precipitational fractionation of the sonicated calf thymus DNA fragments. The relationship between the intrinsic viscosity [η] and the weight-average molecular weight Mw could be expressed with an empirical formula, [η]=9.54×10−6Mw1.35 in cm3g−1 for 1.2×105≤Mw≤3×105, but a sigmoidal change followed with an inflection region (3×105≤Mw≤6×105). The z-averaged square radius of gyration ‹S2›z was also determined from the angular dependence of scattered light intensity for each sDNA sample. The dependence of ‹S2›z and [η] on Mw was calculated theoretically at various values of the persistence length for the A- and B-DNA conformations. It was found that the effect of the polydispersity on ‹S2›z and [η] is important, if a quantitative comparison is made between the observed and calculated quantities.

The effect of polydispersity on transient electric birefringence (EB) was examined for a dilute solution which contains like macromolecules of varying lengths. The molecules were assumed to be rigid rods of cylindrical symmetry, so that the molecular weight is linearly proportional to length. Polydispersity was expressed by the ratio of the weight-average to the number-average lengths lw/ln. A logarithmic-normal type continuous length distribution was generally used. Calculations were performed for the birefringence-average relaxation time ⟨τ⟩EB and initial slope ⟨S⟩EB as a function of the electric field strength E, which is applied prior to the start of the decay process, with the electric parameter (βw)2/2γw, which is related to the weight-average permanent dipole moment (the βw-term) and polarizability anisotropy (the γw-term). Both ⟨τ⟩EB and ⟨S⟩EB are very sensitive to E, lw/ln, and (βw)2/2γw. A convenient method was devised for determining the polydispersity parameters (lw/ln and lw) from the weight-...