Contraction model of skeletal muscle driven by external electrical stimulation-Proposal and Identification.

Biohybrid actuators consisting of skeletal muscle and artificial lattice have unique characteristics such as self-growth and self-repair functions. As a first step for developing model-based design and model-based control methods for the biohybrid actuators, we have developed a muscle contraction model. When the stimulation voltage is applied to the muscle, the electrical charges are stored in the dihydropyridine receptor, and the calcium ions are released. According to the concentration of the ions, the contractile elements generate contraction force. We have modeled this phenomenon with three characteristics in the proposed model-electrical dynamic, physiological, and mechanical dynamic characteristics. Unlike the previous models, the proposed model was verified under the condition of tetanus and incomplete tetanus with the muscle length changed. The simulated contraction force showed good agreement with the experimentally measured contraction force generated by the gastrocnemius muscle of a toad.Clinical Relevance- Biohybrid actuators are expected as a new material for medical and assistive devices having a soft and flexible characteristic. This study provides a basic contraction model for such biohybrid actuators.

Development of a resonance generator utilizing incomplete tetanus of skeletal muscle.

Implantable energy harvesting system utilizing contraction of an electrically-stimulated skeletal muscle is proposed for alternative batteries of implantable medical devices. In order to realize high conversion efficiency, we propose a resonance generator utilizing vibration of the skeletal muscle, which is called as incomplete tetanus. Experimental results showed the incomplete tetanus was a suitable form for the energy harvesting and the stimulation at the frequency of 10 Hz was maximized the work of the muscle. Dimensions of the springs of the generator were designed so that its natural frequency was 10 Hz. On the simulation, the maximum generated power was achieved 122.5 µW, which is enough to power the IMDs.Clinical Relevance-The proposed system has a potential to eliminate conventional batteries in the implantable medical devices. It will be beneficial for patients since the periodical surgery for the battery replacement will be avoided.

Design optimization of contactless generator for implantable energy harvesting system utilizing electrically-stimulated muscle.

We propose an energy harvesting device driven by a contraction of an electrically-stimulated skeletal muscle for an alternative battery of implantable medical devices. In order to realize a durable generator, we proposed a contactless plucking mechanism utilizing parallel leaf springs and magnets, with which the generator can be driven without friction. By utilizing this mechanism, the generator can be driven not only in a contraction phase, but also a relaxant phase. We optimized the stiffness of the parallel leaf springs, air gap between the magnets, and magnetic circuit in order to maximize generated power of the generator. The generated power of the prototype in nonliving environment was evaluated. The result showed the protype could achieve 35.8 µW, the value of which is enough to drive the implantable medical devices. Finally, the generated power was evaluated in the ex-vivo experiment using a gastrocnemius muscle of a toad with a weight of 193.4 g. In this experiment, the generator achieved 18.1 µW from only 3.5 g of the skeletal muscle. Also, we confirmed that the generated power exceeded the power consumption of the electrical stimulation on the skeletal muscle. Hence, we concluded the results showed the feasibility of the energy harvesting system with proposed mechanism.

Development of a contactless energy harvesting system driven by contraction of skeletal muscle for implantable medical devices.

We propose a contactless energy harvesting system driven by the contraction of an electrically-stimulated skeletal muscle to be used to supply electrical energy to implantable medical devices. In order to realize a durable generator, the one proposed here has a contactless clutch mechanism with parallel leaf springs, with which the generator can be driven without friction. In this system, the muscle connected to the parallel leaf spring is intentionally contracted by electrical stimulation. The generator can be driven not only in the contraction phase of the muscle, but also relaxation phase. The result an evaluation showed that the prototype could generate 26.1 $\mu \mathrm{W}$ with an efficiency of 13.7%. Finally, we conducted an animal experiment using the gastrocnemius muscle of a toad with a weighing of200 g The generator was driven in the contraction phase generating 1.37 $\mu \mathrm{W}$ of power from the energy supplied by the muscle.

A uniform and one-dimensional stacking of 2,5-dichlorotetracyanoquinodimethanide molecules in the tetramethylarsonium salt.

In the tetramethylarsonium salt of 2,5-dichloro-7,7,8,8-tetracyanoquinodimethanide [systematic name: tetramethylarsonium 2,2'-(2,5-dichlorocyclohexa-2,5-diene-1,4-diylidene)bis(propanedinitrile)], C(4)H(12)As(+).C(12)H(2)Cl(2)N(4)(-) or [As(CH(3))(4)](C(12)H(2)Cl(2)N(4)), the cation lies disordered about a twofold axis and the radical ion lies about an inversion center forming a uniform [interplanar distance 3.35 (2) A] and one-dimensional stacking without any slip. The electrical conductivity of the single crystal at room temperature was less than 10(-9) S cm(-1), and the temperature dependence of paramagnetic susceptibility obeyed a one-dimensional antiferromagnetic Heisenberg model with a spin-exchange integral of 83 K in the temperature range 1.8-320.0 K.

Tetra-n-butylammonium bis(1,2-dimercaptoethene-1, 2-dicarbonitrilato-S,S')nickel(III)

The crystal structure of the title compound, (C(16)H(36)N)[Ni(C(4)N(2)S(2))(2)], shows stacking of the dimerized anions, surrounded by columns of cations.

Shape Control of Monodisperse Hematite Particles by Organic Additives in the Gel-Sol System.

It has been found that not only inorganic anions such as sulfate and phosphate, but also organic reagents such as dihydroxybenzenes, dihydroxynaphthalenes, ethylenediamine tetraacetic acid (EDTA), and nitrilotriacetic acid (NTA) can be used as a shape controller for forming ellipsoidal hematite (alpha-Fe2O3) particles in the gel-sol system. Specifically, this paper focuses on the formation process of monodisperse ellipsoidal hematite particles with hydroxybenzenes. Interestingly, while 1,3-dihydroxybenzene had no effect on the shape of hematite, 1,4- and 1,2-dihydroxybenzenes could produce ellipsoidal particles. However, 1,4-dihydroxybenzene (hydroquinone) itself turned out to have no ability of adsorption to hematite. It was finally concluded that hydroquinone was oxidatively polymerized to form a kind of humic compound during aging at 100 degreesC for the growth of hematite particles, controlling the anisotropic growth by adsorption of the polymerized species. In addition, a considerable amount of the adsorbed polymer was found to be retained in the internal grain boundaries of the subcrystals, as revealed from XPS, XRD, and FT-IR analyses. Lastly, the mechanism of shape control by 1,2-dihydroxy-3,5-benzenedisulfonic acid disodium salt (Tiron) which is directly adsorbed to growing hematite particles is also discussed. Copyright 1998 Academic Press.

[Comparison of formulas for calculating average skin temperature and their characteristics].

In order to obtain data of skin temperatures experiments were carried out using three healthy young Japanese males. The subjects were exposed to each of the four environments with dry bulb temperatures of 15 degrees C, 19 degrees C, 25 degrees C and 33 degrees C. At each of these air temperatures, relative humidity and air movement were set at 50% and 0.15m/s respectively. The subjects wore only athletic shorts, seated on the meshed chair. Each subject was measured with thermisters continuously for one hour under these conditions to obtain twenty-nine regional skin temperature. The above experiments were made with one subject at a time in the test chamber. The data of skin temperatures observed were substituted into twenty-eight different weighting formulas for comparison. The present analysis revealed that the calculation from the 12-point and the 7-point skin area formulas by Hardy-DuBois showed approximate mean values of the twenty eight. Moreover, the values calculated from the formula by Nadel et al, which was weighted by skin area and thermal sensitivity, are similar to the values calculated by the formula of Mochida, which was weighted by skin area, heat transfer coefficients and thermal sensitivity. Furthermore, the authors verified that the area-mean weighting factor was derived from the Teichner's definition in which a limiting value of arithmetical mean of skin temperatures gave a value of average skin temperature.

[Values of wettedness observed in clothed subject and the theoretical equal line of average skin temperature].

In order to obtain the characteristics of the change of wettedness under constant average skin temperature 36 degrees C, the experiments were carried out using two young male subjects in a test chamber. From the basic measurements of both environmental parameters and human physiological responses, the authors found the wettedness value changeable even though the average skin temperature was constant. The following results were obtained under the conditions of resting-sitting, summer clothing worn, still air movement and constant average skin temperature 36 degrees C; 1. there is a positive correlation between wettedness and the environmental vapor pressure. 2. There is a negative correlation between wettedness and the air temperature. 3. There is a positive correlation between the evaporative heat loss from skin surface and the air temperature. 4. There is a negative correlation between the evaporative heat loss and the vapor pressure. 5. There is a negative correlation between wettedness and the evaporative heat loss. 6. Both maximum and minimum values of wettedness correspond to the average skin temperature. Considering the afore-mentioned results, the equal line of the average skin temperature does not form a straight line, but a curved line on the psychrometric chart.

[Fundamental study regarding the characteristics of wetness under constant average skin temperature].

This paper deals with the characteristics of wetness under constant average skin temperature and its effect on the equal skin temperature lines. From the basic measurements of both environmental parameters and human physiological responses, the following results were obtained: Under the condition of constant activity level, clothing worn, air movement and constant average skin temperature, 1. there is a positive correlation between the wetness and the environmental humidity. 2. there is a negative correlation between the wetness and the air temperature. 3. there is a negative correlation between the wetness and the evaporative heat loss. 4. both the maximum and the minimum wetness values corresponding to each average skin temperature exist. The theoretical examinations regarding the above-mentioned items--the characteristics of wetness under the constant average skin temperature were extended, and we finally obtained the following; the locus of equal skin temperature is not a straight one but a curve on the psychometric chart.

[Blood coagulation and fibrinolysis activities during normal pregnancy and fetal growth--study based on estimated fetal body weight].

There are many factors influencing the growth of the fetus. Since these factors have complex interrelations, they are difficult to clarify. The authors studied the effects of blood coagulation and fibrinolysis on the growth of the fetus during pregnancy, especially from the 2nd trimester into the 3rd trimester. The subjects were 86 normal pregnant women, and the subjects of study were blood coagulation, fibrinolysis activity of the mother, and estimated fetal birth weight after the 28th (2nd trimester) and 36th weeks of gestation (3rd trimester) in each case. 1. Changes in blood coagulation activity and fibrinolysis varied from the 2nd trimester into the 3rd trimester. The percentage of cases showing lowered platelets was 68.6% of the total, and the percentages of cases with reduced platelet ADP, epinephrine, and collagen aggregation were 60.5%, 55.8%, and 51.2%, respectively. The percentages of cases showing shortened prothrombin time and activated partial thromboplastin time were 58.1% and 51.2% of the total, respectively. The percentage of cases with reduced fibrinogen was 24.4% of the total. The percentages of cases with reduced antithrombin III, plasminogen, and alpha 2-plasmin inhibitor activity were 66.3%, 55.8%, and 75.6% of the total, respectively. 2. The birth weight of babies in a group with shortened prothrombin time was 2,935.1 +/- 395.2g(n = 50, mean +/- SD), while that in a group with prolonged prothrombin time was 3,106.2 +/- 357.9g(n = 36). The estimated fetal birth weight gain from the 2nd trimester to the 3rd trimester was 1,431.6 +/- 296.5g in the former group and 1,644.5 +/- 390.5g in the latter group. The differences were significant (p less than 0.05, p less than 0.01). The birth weight of babies in a group with lowered antithrombin III activity was 2,960.1 +/- 341.3g(n = 57), and that in an acceleration group was 3,157.8 +/- 370.0g(n = 29). The estimated fetal weight gain from the 2nd trimester to the 3rd trimester was 1,477.7 +/- 281.9g in the former group and 1,637.1 +/- 390.6g in the latter group. The differences were significant (p less than 0.02, p less than 0.05). 3. The estimated fetal weight gain from the 2nd trimester to the 3rd trimester in the group showing prolongated prothrombin time and activated partial thromboplastin time in this period was significantly larger than in the group showing shortened prothrombin time and activated partial thromboplastin time (p less than 0.001). These results suggested that the changes in blood coagulation and fibrinolysis activity of mothers from the 2nd trimester to the 3rd trimester affected the growth of the fetus.

Antenatal sonographic diagnosis of exencephaly.

We herein present a case of exencephaly with rachischisis, situs ambiguous and club feet, diagnosed antenatally by ultrasound. This combination of anomalies is very rare.

Empiema da vesicula biliar. Relato de um caso. / Gallbladder empyema. Report of a case

Os autores relatam um caso de empiema de vesicula biliar e seus resultados ultrassonograficos

Diagnostico diferencial em espessamento pleural. / Differential diagnostic of pleural inspissation

Os autores decrevem um caso de um paciente idoso com carcinoma bronquica, no qual havia intensa fibrose pleural, raramente encontrada nesses casos