Showing papers by "University of Jyväskylä published in 1982"

Combined effect of elastic energy and myoelectrical potentiation during stretch-shortening cycle exercise

Abstract: In addition to the utilization of muscle's elastic energy enhancement of performance in exercise involving stretch-shortening cycle might be also due to simultaneous increase of myoelectrical activity. This hypothesis was tested by examining three athletes during jumping exercise on force-platform. Vertical jumps were performed with and without preliminary counter-movement, and the jumps were called counter-movement jump (CMJ) and squatting jump (SJ), respectively. In both conditions several jumps were performed also with extra loads on the shoulders (15–220% of b. wt.). Additional droppingjumps (DJ) were executed from different heights (20–100 cm). During jumping exercise myoelectrical activity of selected muscles from the quadriceps femoris was monitored with surface electrodes. The results obtained were similar to those reported in isolated muscle and as expected, the prestretch in CMJ shifted the force-velocity curve of concentric work to the right. In two cases enhancement of performance was attributed primarily to restitution of elastic energy because myoelectrical activity was similar to that observed in SJ. In one subject increased myoelectrical activity was observed during the concentric phase of CMJ. In DJ condition the EMG activity during eccentric phase was much higher than in SJ. Therefore the high performance in this condition was attributed to both elastic energy and reflex potentiation. In eccentric work of CMJ the average force decreased with the increase of stretching speed. This phenomenon was associated with a light increase of EMG activity. The observed results emphasize that both elastic energy and reflex potentiation may operate effectively during stretch-shortening cycle activity.

Neuromuscular function and mechanical efficiency of human leg extensor muscles during jumping exercises.

Abstract: The influence of prestretch amplitude on the mechanical efficiency was examined with 5 subjects, who performed 5 different series of vertical jumps, each of which differed with respect to the mechanics of the knee joint action during the prestretch (eccentric) phase of the contact on the floor. Electromyographic activity was recorded from the major extensor muscles during the entire work period of 1 min per series. In addition, expired air was collected during the test and recovery for determination of energy expenditure. Mechanical work was calculated from the vertical displacement of the body during the jumps. The results indicated that high net efficiency of 38.7% was observed in condition where amplitude of knee bending in eccentric phase was small. In large range motion the corresponding net efficiency was 30.1%. In jumps where no prestretching of extensor muscles occurred the net efficiency was 19.7%. The high efficiency of small amplitude jumps was characterized by low myoelectrical activity of the leg extensor muscles during the positive (concentric) work phase. In addition, the small amplitude jumps had shorter transition time in the stretch-shortening cycle, high average eccentric force and high stretching speed. Therefore the results suggest that the restitution of elastic energy, which was also related to the length change and stiffness of the muscles during stretch, plays an important role in regulating the mechanical efficiency of work.

Store and recoil of elastic energy in slow and fast types of human skeletal muscles

Abstract: Stretch-shortening cycle refers to the mechanical condition in which store and recoil of elastic energy occur in the skeletal muscle. This leads to a greater work output when compared to a simple shortening contraction. The subjects performed vertical jumps with and without preliminary counter-movement and with small and large knee angular displacement. The results indicated that those subjects who had more fast twitch (FT) fibers benefited more from the stretching phase performed with high speed and short angular displacement. The amounts of elastic energy stored in this phase were 30 and 26 N X kgBW-1, respectively, for FT and slow twitch (ST) type subjects. The recoil of elastic energy was proportional to the amount of energy storage. In large amplitude jumps where transient period between stretch and shortening is long the both types of subjects demonstrated similar amount of storage of elastic energy (17 and 16 N X kgBW-1, respectively). However, the re-use of this elastic energy was greater in ST group (24%) as compared to the FT group (17%). The results can be interpreted through differences in sarcomere crossbridge life times between fast and slow muscle fibers. The slow type muscle may be able to retain the cross-bridge attachment for a longer period of time and therefore it may utilize elastic energy better in a slow type ballistic motion.

Electromechanical behaviour of human muscles in vertical jumps.

Abstract: The relationships of muscle structure to the potentiation of myoelectrical activity and to the use of prestretching in five lower limb muscles were studied in different vertical jumping conditions. The subjects for the study were six male students, divided according to the muscle fiber distribution in m. vastus lateralis into “fast” and “slow” groups. The subjects performed vertical jumps (1) from a static squatting position (SJ), (2) with a preliminary counter movement (CMJ) and (3) after dropping (DJ) from five different heights. Myoelectrical (EMG) activity was recorded from mm. gluteus maximus, vastus lateralis, vastus medialis, rectus femoris and gastrocnemius in each jumping condition and integrated (IEMG) for the eccentric and concentric phases of contact. EMG activity showed potentiation during the eccentric phase of movement when compared to the concentric phase. The “fast” and “slow” groups did not differ significantly in this respect, whereas in DJ conditions the relative (% from SJ) height of rise of the center of gravity was greater in the “slow” than in the “fast” group. The result indicated that the utilization of elastic energy during jumping was possible better in subjects having a high percentage of slow twitch muscle fibres in their vastus lateralis muscles.

Embedded-atom calculations of Auger and x-ray photoemission shifts for metallic elements

Abstract: Powered by TCPDF (www.tcpdf.org) This material is protected by copyright and other intellectual property rights, and duplication or sale of all or part of any of the repository collections is not permitted, except that material may be duplicated by you for your research use or educational purposes in electronic or print form. You must obtain permission for any other use. Electronic or print copies may not be offered, whether for sale or otherwise to anyone who is not an authorised user. Nieminen, R. M.; Puska, M. J.

Periphyton growth and diatom community structure in a cooling water pond

Abstract: Periphyton (Aufwuchs) accumulation was measured on artificial substrates in a pond in central Finland which receives warm cooling-water effluent from a power plant. The growth of periphyton was generally more rapid on the substrates during the first two weeks of colonization near the inflow of the warm water effluent than in the middle of the pond. The maximum accumulation of periphyton was in spring and autumn (dry weight maximum at warm effluent was in spring 3.5 mg DW cm−2,2.65 mg AFDW cm−2; chlorophyll a maximum 3.96 µg cm−2 was found in autumn at pond-middle station). During mid-winter months the growth was strongly limited by solar radiation, but the growth was also slow at both stations in the summer months, when the power plant was out of operation. The periphyton accumulation rate was fastest near the water surface and decreased rapidly with increasing depth. A total of 167 diatom species were found in periphyton samples. However, most species were rare; many of the dominants were common to both plankton and periphyton. Species similarity analyses (Jaccard's similarity) between 10 different diatom communities (including periphyton from 9 different types of substrates and phytoplankton) indicated low similarity index values although differences between communities were not significant.

Gas chromatographic and mass spectrometric analysis of chlorinated catechols occurring in pulp bleach liquors

Abstract: Chlorination step (C-step), spent bleach liquor from a kraft pulp mill and the product from the chlorination of guaiacol in aqueous solution have been investigated for their content of chlorinated catechols. After separation the samples were derivatized with diazoethane and analysed by glass capillary gas chromatography with an electron capture detector. The external standard mixture of all ethylated chlorocatechols was used in the measurements. The structures of the compounds identified were confirmed by gas chromatography/mass spectrometry. Eight chlorinated catechols were identified from a sample prepared by chlorination of guaiacol with Cl2 in aqueous solution. However, only four of these compounds could be detected from a bleach liquor sample.

Glass capillary gas chromatography of chlorinated methyl acetates, propanoates and butanoates on Carbowax 20M and SE-30 columns

Abstract: The gas chromatography of all chlorinated methyl acetates, methyl propanoates and methyl mono- and dichlorobutanoates has been studied on Carbowax 20M and SE-30 glass capillary columns under various running conditions. The order of elution on a non-polar column was largely determined by the boiling point of esters, whereas on a polar column it was much influenced by the structure of compounds. Complete separation of the combined mixture of all 27 compounds could not be achieved, however, methyl 3,3-dichlorobutanoate was the only ester overlapped on both columns in spite of the various column temperatures used. The best separation of the mixture was on Carbowax 20M with a temperature program from 50°C at 8°C/min, isothermal running conditions leading either to poor separation of volatile components or long analysis time and broad peaks of higher chlorinated esters. The relative retention times for compounds at the various column temperatures are given and the retention order on a polar and on a non-polar column discussed.

Simultaneous determination of C1−C8 n-alkyl acetates and corresponding mono-, di- and trichloroacetates on glass capillary columns with programmed temperature rise

Abstract: Gas chromatography of mixtures of aliphaticn-alkyl acetates (CH3−COOR), chloroacetates (CHCl2−COOR), dichloroacetates (CHCl2−COOR) and trichloroacetates (CCl3−COOR), where the alcohol chain length (R) varied between 1 and 8, has been studied on SE-30, Carbowax 20M and OV-351 glass capillary columns with programmed temperatures from 50°C at 2, 4, 6, 8 and 10°C/min. Compounds in the homologous series are eluted in the direct order from methyl ton-octyl acetate. The isomeric chloro esters are eluted on SE-30 according to their boiling points in the order: mono-, di- and trichloro isomer, whereas on polar columns di- and trichloro esters are eluted in the reverse order. The complete separation of all 32 individual components from the mixture could not be reached by any single column, the best separation occurred on SE-30. The mixture can, however, be separated by using columns with polar and non-polar stationary phases. The relative retention times for the compounds are given and the retention order discussed.

Experiences of structure analyses of chlorophenol dimers and trimers found in different samples

Abstract: Chlorophenol formulations (Kymi/Kymmene Co., wood preservatives), sawmill wood waste samples and different waste treatment product samples were analyzed for oligomeric by-products of the polychlorinated phenols. Structure types for 26 phenolic dimers, 45 neutral dimers and 13 phenolic trimers were determined by GC/MS. Types of one tetrachloro and one hexachloro compound detected remained unknown. Contents of by-products in chlorophenol formulations varied greatly depending on their production method. Chemical treatment of wastes with NaClO and NaOH lowered their contents of chlorophenols and phenolic dimers, but did not change (NaOH) or increased (NaClO) the contents of neutral dimers (PCDPE, PCDD and PCDF). Open fire burning of chlorophenol formulation removed all polychlorinated diphenyl ethers (PCDPE) but the amounts of polychlorinated dioxins (PCDD) increased greatly and those of dibenzofurans (PCDF) increased slightly. High efficient burning experiments of wastes mixed with bark removed practically all PCDD:s and PCDF:s also, most completely when the amount of the pure bark mixed was high.

Gas chromatographic study of acetyl derivates of chlorinated guaiacols

Abstract: The gas chromatography of acetyl derivatives of guaiacol and all chlorinated guaiacols has been studied on SE-30, OV-351 and Carbowax 20M capillary columns. The retention order and relative retention times under isotermal and temperature-programmed conditions are discussed. Different retention times for all mono- and dichloro compounds have been observed on the SE-30 column. However, all trichloroguaiacol isomers were separated only on polar columns. The best overall temperature-programmed separations have been achieved on an SE-30 capillary column.

Particle octupole multiplet in147Gd

Abstract: Levels of the N=83 nucleus147Gd have been investigated by in-beam γ-ray and conversion-electron spectroscopy using the147Sm(3He,3n) and Sm(α,n) reactions. We have observed 16 new low-and medium-spin levels in147Gd. In addition to the previously known 13/2+ level we have located the 11/2+,9/2+, 7/2+, 3/2+ and (1/2)+ members of the vf7/2×3 septuplet.

Studies on vinblastine-induced autophagocytosis in mouse liver. III. A quantitative study.

Abstract: Intraperitoneal injection of two doses of vinblastine (10 mg/kg and 50 mg/kg) induced a prominent formation of autophagic vacuoles in mouse liver parenchymal cells in 4 h Clearly recognizable organelles were seen inside these vacuoles The amount of autophagy was dependent on doses in that autophagosomes almost disappeared within 12 h with the low dose, whereas with the high dose the cells were filled with residual bodies Defecation of lysosomal material was observed into the sinusoidal lumen 12 h after injection with the high dose The total activities of lysosomal enzymes acid phosphatase, s-galactosidase, and β-acetylglucosaminidase did not change in the liver after vinblastine administration The soluble activities of β-galactosidase and β-glucosaminidase were elevated with the high dose 12 h after injection, indicating labilization of the lysosomal membranes Simultaneously the activities of the three lysosomal enzymes were elevated in the serum The injurious effect of VBL appeared in light- and electron microscopic levels indicating diffuse necrosis of the liver lobules with the high dose within 12 h, fat accumulation in the cells, accumulation of secretory vesicles containing very low density lipoprotein particles, partial dilatation, vesiculation of endoplasmic reticulum and dilatation of Golgi cisternae The serum GOT and CPK levels were also elevated

In-beam studies of203, 205Bi and shell-model features of odd-a bismuth isotopes

Abstract: States in203, 205Bi are populated using the reaction203, 205Tl(3He,3n). Theπi13/2 single-proton states and all the members of thev(21+)⊗π h9/2 quintuplet are identified in both nuclei. The half-lives of the isomericJπ=21/2+ states in both isotopes are measured and found to be 90±7 ns and 100±6 ns, and from these values suggestions for the half-lives of the previously reportedJπ=25/2+ isomers are made. The structures of the multiplets of the formv(Pb)⊗π h9/2 are calculated in the framework of the shell model and it is shown that the main features can be derived from theπ−v−1 effective interaction. The wave functions of the 41+ and 40+ states in202, 204pb are deduced indirectly from the calculation in203, 205Bi.

Studies on coordination compounds vii, chromatographic, thermoanalytical and spectroscopic studies on thermal decomposition of cadmium(II) and lead(II) salicyl-aldoximates

Abstract: On the basis of decomposition temperatures and infrared spectra, cadmium(II) and lead(II) bissalicylaldoximates were considered to havetrans andcis structures, respectively.

Electron impact mass spectra of chlorinated methyl propanoates

Abstract: The mass spectral fragmentations of all eleven chlorinated methyl propanoates have been studied. Deuterium labelling and metastable ion analysis were used to elucidate the fragmentation mechanism. The molecular ion peaks of all compounds are small, except methyl 3,3-dichloropanoate (38%). In most cases α-cleavage gives the base peak [COOCH3]+, and the loss of a chlorine atom from the molecular ion is characteristic of the 3-chloro, 3,3-dichloro and 3,3,3-trichloro compounds. Metastable ions showed the losses of small neutral molecules such as CH3OH, CH2CO, CO2 and CO from the [MCl]+ ion. α-Cleavage and the loss of Cl˙ gives an intense [MCOOCH3Cl]+˙ peak, which is the base peak in the spectra of the 2,3-dichloro and 2,3,3-trichloro compounds.