Significant Increase In Mass Research Articles

Synthesis, optimization and experimental validation of reactionless two-DOF parallel mechanisms using counter-mechanisms

The synthesis of reactionless mechanisms generally involves the force balancing of a mechanism using countermasses followed by the dynamic balancing of the inertia using counter-rotations. This approach requires that the force balanced mechanism have a constant equivalent moment of inertia for any configuration. Two of the main drawbacks of reactionless mechanisms are a significant increase in mass and actuation inertia. In this paper, a counter-mechanism is introduced in order to dynamically balance a force balanced two-DOF mechanism with variable inertia, which is expected to reduce the aforementioned drawbacks. The conditions for which the counter-mechanism matches the moment of inertia of the main mechanism for any configuration are derived. Then, in order to fairly compare the use of a counter-mechanism instead of counter-rotations, the balancing strategies are optimized regarding the addition of mass and actuation inertia using Lagrange multipliers. The results are optimal rules for the design of reactionless mechanisms and optimal mass-inertia curves which are akin to Pareto curves. These results allow to demonstrate the advantages of counter-mechanisms over counter-rotations, especially regarding added actuation inertia and compactness. Also, the significant influence of the radius of gyration of the counter-inertias on the optimal mass-inertia curves is revealed. Finally, examples of reactionless mechanisms are presented and prototypes are tested in order to validate the concepts.

Characterization of the HS-C6-Aptamer/Mercaptohexanol Monolayer on Gold Electrodes

The purpose of this study was to determine characteristic parameters of aptamer-modified electrodes. These parameters are substantial for the development of an impedance model, based on equivalent circuits. This study contributes to the understanding of electron transfer kinetics for the detection of aptamer binding events. The Protein A-binding aptamer (PAA) was co-immobilized to form an aptamer/mercaptohexanol(MCH)-mixed monolayer on gold electrodes. Functionalization and binding of recombinant Protein A were verified by the use of quartz crystal microbalance (QCM) and chronocoulometry (CC). A significant mass increase of 255±108 ng/cm2 after aptamer immobilization was measured with QCM while with CC we quantified immobilized aptamers as 1.85±0.34.1012 molecules/cm2. The modified electrodes were further characterized by cyclic voltammetry (CV) and chrono-coulometry (CC), obtaining characteristic values as the diffusion coefficients Dred and Dox and the electron transfer rate k0. Herein, blank electrodes and those covered with a MCH monolayer were compared to aptamer functionalized electrodes. The electron transfer rate k0 of the aptamer electrode tends to range between the blank and the MCH electrodes indicating that the immobilization of aptamers introduces defects into the MCH monolayer.

Developmental Exposure to Aroclor 1254 Alters Migratory Behavior in Juvenile European Starlings (Sturnus vulgaris).

Birds exposed to endocrine disrupting chemicals during development could be susceptible to neurological and other physiological changes affecting migratory behaviors. We investigated the effects of ecologically relevant levels of Aroclor 1254, a polychlorinated biphenyl (PCB) mixture, on moult, fattening, migratory activity, and orientation in juvenile European starlings (Sturnus vulgaris). Birds were orally administered 0 (control), 0.35 (low), 0.70 (intermediate), or 1.05 (high) μg Aroclor 1254/g-body weight by gavage from 1 through 18 days posthatch and later exposed in captivity to a photoperiod shift simulating an autumn migration. Migratory activity and orientation were examined using Emlen funnel trials. Across treatments, we found significant increases in mass, fat, and moulting and decreasing plasma thyroid hormones over time. We observed a significant increase in activity as photoperiod was shifted from 13L:11D (light:dark) to 12L:12D, demonstrating that migratory condition was induced in captivity. At 12L:12D, control birds oriented to 155.95° (South-Southeast), while high-dosed birds did not. High-dosed birds showed a delayed orientation to 197.48° (South-Southwest) under 10L:14D, concomitant with apparent delays in moult. These findings demonstrate how subtle contaminant-induced alterations during development could lead to longer-scale effects, including changes in migratory activity and orientation, which could potentially result in deleterious effects on fitness and survival.

Hygroscopic effects on the mobility and mass of cigarette smoke particles

The hygroscopic growth of particles, produced from a University of Kentucky 3R4F reference cigarette smoked following Health Canada Intense (HCI) puffing parameters (55mL puff of 2s duration, every 30s), was measured in terms of the electrical mobility diameter and particle mass, using a Hygroscopic Tandem Differential Mobility Analyzer (HTDMA) and Centrifugal Particle Mass Analyzer (CPMA) system. Both the particle mobility diameter and mass growth factors were found to agree with previously determined values and hygroscopicity models. The mobility diameter growth factor of the particles produced from either a University of Kentucky 3R4F or 1R5F reference cigarette, following HCI puffing parameters, were found to be very similar. As the relative humidity (RH) approached saturation, the effects of the initial particle size on the mobility growth factor became more dominant, with larger particles growing proportionally larger than smaller particles. From the measured mobility diameter and mass growth factors, the density growth factor was calculated. This parameter showed that the particle density increased as the sample relative humidity increased. This case is only possible, given that the dried smoke particle density (1109±118kg/m3) was determined to be greater than the density of water, if the water condensation on the smoke particle dissolves at least a portion of it, resulting in a significant increase in mass with only a small increase volume.

The Study of Electrodeposition of Si in Tmhatfsi-SiCl4 analyzed by EQCM Method

An inexpensive fabrication method of Si is required for achieving Ultra-Large-Scale Si solar power generation. Electrodeposition method has attracted recently because it has numbers of advantages such as simplicity of process and precision control of reaction etc. compared with conventional methods such as CVD, sputtering and e-beam evaporation. Si electrodeposition has been conducted using nonaqueous solvents (molten solt1), organic solvent2) and ionic liquid3)) because the reduction potential of SiO2 is very negative. However, the organic solvents have a drawback due to safety concerns, with high flammability. On the other hand, ionic liquids (sometimes referred as room temperature molten salts) exhibit low volatility and in many cases are nonflammable. The primary benefit of both systems is the large electrochemical window, allowing for study of elements such as Si and Li. We have reported the electrodeposition of Si from an ionic liquid.4) However, high purity Si electrodeposition has not been demonstrated yet. Si electrodeposition layers include some impurities stemmed from ionic liquids.5) It is caused by the uncertainty on Si electrochemical reaction mechanism. Electrochemical quartz microbalance (EQCM) impedance method could provide us to obtain in-situ information about the mass change during electrodeposition. Such information might further support our deduction on electrochemical reaction mechanism. Here we present the results of our recent work on the analysis of Si electrodeposition using EQCM method. Si is electrodeposited at 40 °C in an ionic liquid, specifically tri-methylhexyl ammonium bis-(trifluorosulfonyl) imide (TMHATFSI). In particular, we focus on the mass change during cyclicvoltammogram and chronoamperometry. Figure1 demonstrates that Si deposition starts around -2.2 V because a significant mass increase is observed with the increase of the current density. It corresponds to our previous study.5) Therefore we could propose Si electrochemical reaction mechanism more clearly than before from this EQCM result. This study was financially supported in part by CREST program by Japan Science and Technology Agency (JST).1). Y. Nishimura, Y. Fukunaka, T. Nishida, T. Nohira, and R. Hagiwara. Electrochem. Solid State Lett. 11 (9) D75-79 (2008)2). Y. Nishimura and Y. Fukunaka. Electrochim. Acta. 53, 111-116 (2007)3). F. Endres, A.P. Abbott, and D.R. MacFarlane. Electrodeposition from Ionic Liquids. Wiley-VCH. 2008.4). T. Homma, J. Komadina, Y. Nakano, T. Ouchi, T. Akiyoshi, Y. Ishibashi, Y. Nishimura, T. Nishida, Y. Fukunaka, Electrochem. Soc. Trans., submitted.5). J. Komadina, T. Akiyoshi, Y. Ishibashi, Y. Fukunaka, T.Homma. Electrochim.Acta, 100, 236-241 (2013)

Impact of long-term zero till wheat on soil physical properties and wheat productivity under rice–wheat cropping system

Information about the changes in soil properties upon change in the agricultural management system is essential for sustainability of the system. The long-term (15 years) impact of zero tillage in wheat under rice–wheat cropping system in semi-arid region of Indo-Gangetic Plains (IGP) was evaluated for physical properties, organic carbon build up, root growth and wheat productivity in different textured soils. The conventional (CT, two harrowing, one cultivator and planking) and zero tillage (ZT, direct drilling) systems were investigated.ZT increased soil organic carbon significantly to a depth of 0.10, 0.15 and 0.25m in sandy loam, loam and clay loam soil, respectively, indicating its buildup to deeper depths with increase in fineness of soil texture. Carbon stock in surface 0.4m soil depth increased by 19.0, 34.7 and 38.8% over CT in 15 years in sandy loam, loam and clay loam soil, respectively. The corresponding carbon sequestration rates were 0.24, 0.46 and 0.62Mgha−1year−1. It reduced the plough pan, however, a significant increase in bulk density was observed in surface 0.05m in sandy loam and 0.10m in both loam and clay loam soils. Water dispersible silt+clay reduced indicating better soil aggregation. Saturated hydraulic conductivity increased significantly only to a depth of 0.10m but with varying magnitudes. Increase in magnitude in surface 0.05m layer was highest in loam (51%) followed by sandy loam (40%) and clay loam (38%) soil. Although ZT increased water retention and aeration porosity but increase in field water capacity was significant to a deeper depth (0.15m) in clay loam soil. Water intake rate also increased significantly in clay loam soil (28%) over CT. The root biomass increased significantly and the highest increase was recorded in loam (81%) followed by sandy loam (70%) and clay loam (42%) soil. In addition, ZT encouraged roots to penetration deeper in the soils.In spite of improved soil physical properties and root growth under ZT, the significant increase in mass of grains and consequently the wheat yield, was observed only in clay loam soil indicating that the physical properties of other soils under CT have not reached to a stage limiting plant growth and yields. Study concludes that the ZT practice in wheat under rice–wheat system of semi-arid region of IGP in Haryana may be adopted for sustaining productivity of the system but the implementation of the practice must be promoted in fine textured soils.

Oxidative stress in abalone: The role of temperature, oxygen and l-proline supplementation

In their natural distribution range and in on land-based mariculture facilities, Haliotis midae may be exposed to a relatively wide range of temperatures and oxygen levels, that can induce differential degrees of stress with concomitant metabolic responses.In the current study juvenile H. midae were exposed for one month to two constant temperatures (14°C and 19°C), with three oxygen levels (82%, 98% and 126% oxygen saturation) at each temperature. One additional treatment was included at 19°C, 126% oxygen, where feed was supplemented with l-proline. The results presented here suggest that long-term 19°C exposure is more stressful to H. midae juveniles than a 14°C exposure of the same duration, since exposure to higher temperature generally resulted in higher activities of the antioxidant enzymes measured but lower total antioxidant capacities. Haemolymph glucose levels responded to oxygen treatment at the 14°C exposure, but the same response was not initiated in the 19°C treatment, possibly because the animals exposed to the 19°C treatment relied on proteins to a larger extent.Increased oxygen levels at the 19°C treatment did not cause more DNA damage or protein carbonylation compared to lower oxygen levels. Supplementing feed with l-proline at the high temperature/high oxygen treatment caused a decrease in haemolymph haemocyanin (which may exhibit catalase function) content and a slight decrease in some of the antioxidant enzyme activities, while maintaining the same total antioxidant capacity compared with the same treatment where feed was not supplemented. The overall DNA integrity profile also changed with proline-supplementation, as did the induction level of hsp70. When projecting tissue growth over a 12month period under these conditions, we estimate that H. midae juveniles in this study may exhibit a significant increase in mass when their feed was supplemented with l-proline, indicating that l-proline supplementation provides some benefit to the individual. It might therefore warrant conducting long-term growth trials on land-based mariculture facilities to further investigate its potential benefit to the mariculture industry.

Effects of Vehicle Front-End Stiffness on Rear Seat Dummies in NCAP and FMVSS208 Tests

Objective: This study is devoted to quantifying changes in mass and stiffness of vehicles tested by the National Highway Traffic Safety Administration (NHTSA) over the past 3 decades (model years 1982 to 2010) and understanding the effect of those changes on protection of rear seat occupants. Methods: A total of 1179 tests were used, and the changes in their mass and stiffness versus their model year was quantified. Additionally, data from 439 dummies tested in rear seats of NHTSA's full frontal crashes were analyzed. Dummies were divided into 3 groups based on their reference injury criteria. Multiple regressions were performed with speed, stiffness, and mass as predicting variables for head, neck, and chest injury criteria. Results: A significant increase in mass and stiffness over model year of vehicles was observed, for passenger cars as well as large platform vehicles. The result showed a significant correlation (P-value < .05) between the increase in stiffness of the vehicles and increase in head and chest injury criteria for all dummy sizes. Conclusions: These results explain that stiffness is a significant contributor to previously reported decreases in protection of rear seat occupants over model years of vehicles. Supplemental materials are available for this article. Go to the publisher's online edition of Traffic Injury Prevention to view the supplemental file.

Technology of preparing anode films and the effect of co-sensitization in dye-sensitized solar cells

Nanocrystalline N-Zn/TiO2 anode films were prepared by doping element N and Zn. These element-doped films have a better performance in dye-sensitized solar cell than the non-doped film. The test shows that the best thickness of N-Zn/TiO2 anode film is 13.5 mu m. UV-Visible measurements show that there is a complementarity in ultraviolet-visible absorbance range between P3OT and N719, both are used as dyes in this study, the former is prepared and the latter is commercially available. SEM shows a significant mass increase of anode film after treated with TiCl4. Solar cells based on N-Zn/TiO2 anode film with TiCl4 treatment was firstly co-sensitized by N719/P3OT. A solar-to-electric energy conversion efficiency of 3.54 % was obtained. Compared with the traditional dye-sensitized solar cell, the photoelectric conversion efficiency, V (oc) and J (sc) have been increased. Nanocrystalline N-Zn/TiO2 anode films were prepared by doping element N and Zn. These element-doped films have a better performance in dye-sensitized solar cell than the non-doped film. The test shows that the best thickness of N-Zn/TiO2 anode film is 13.5 mu m. UV-Visible measurements show that there is a complementarity in ultraviolet-visible absorbance range between P3OT and N719, both are used as dyes in this study, the former is prepared and the latter is commercially available. SEM shows a significant mass increase of anode film after treated with TiCl4. Solar cells based on N-Zn/TiO2 anode film with TiCl4 treatment was firstly co-sensitized by N719/P3OT. A solar-to-electric energy conversion efficiency of 3.54 % was obtained. Compared with the traditional dye-sensitized solar cell, the photoelectric conversion efficiency, V (oc) and J (sc) have been increased.

Studies on ignition and afterburning processes of KClO4/Mg pyrotechnics heated in air

Thermal behavior of KClO4/Mg pyrotechnic mixtures heated in air was investigated by thermal analysis. Effects of oxygen balance and heating rates on the TG–DSC curves of mixtures were examined. Results showed that DSC curves of the mixtures had two exothermic processes when heated from room temperature to 700 °C, and TG curve exhibited a slight mass gain followed by a two-stage mass fall and then a significant mass increase. The exothermic peak at lower temperature and higher temperature corresponded to the ignition process and afterburning process, respectively. Under the heating rate of 10 °C min−1, the peak temperatures for ignition and afterburning process of stoichiometric KClO4/Mg (58.8/41.2) was 543 and 615 °C, respectively. When Mg content increased to 50%, the peak ignition temperature decreased to 530 °C, but the second exothermic peak changed little. Reaction kinetics of the two exothermic processes for the stoichiometric mixture was calculated using Kissinger method. Apparent activation energies for ignition and afterburning process were 153.6 and 289.5 kJ mol−1, respectively. A five-step reaction pathway was proposed for the ignition process in air, and activation energies for each step were also calculated. These results should provide reference for formula design and safety storage of KClO4/Mg-containing pyrotechnics.

Equilibrium Removal of Pb (II) Ions from Aqueous Solution onto Oxidized-KOH-Activated Carbons

In the present study, the removal of Pb (II) ions on oxidized activated carbons (ACs) was investigated. ACs were derived from activation of indigenous cotton stalks waste with potassium hydroxide (KOH) in two-stage process. The KOH-ACs were subjected to liquid-phase oxidation with hot <TEX>$HNO_3$</TEX> and one untreated sample was included for comparison. The obtained carbons were characterized by Fourier transform infrared (FTIR), slurry pH and <TEX>$N_2$</TEX>-adsorption at 77 K, respectively. Adsorption capacity of Pb (II) ions on the resultant carbons was determined by batch equilibrium experiments. The experimental results indicated that the oxidation with nitric acid was associated with a significant increase in mass of yield as well as a remarkable reduction in internal porosity as compared to the untreated carbon. The AC-800N revealed higher adsorption capacity than that of AC-800, although the former sample exhibited low surface area and micropore volume. It was observed that the adsorption capacity enhancement attributed to pore widening, the generation of oxygen functional groups and potassium containing compounds leading to cation-exchange on the carbon surface. These results show that the oxidized carbons represented prospective adsorbents for enhancing the removal of heavy metals from wastewater.

Evaluation of Systemic Follistatin as an Adjuvant to Stimulate Muscle Repair and Improve Motor Function in Pompe Mice

Due to the lack of acid alpha-glucosidase (GAA) activity, Pompe mice develop glycogen storage pathology and progressive skeletal muscle dysfunction with age. Applying either gene or enzyme therapy to reconstitute GAA levels in older, symptomatic Pompe mice effectively reduces glycogen storage in skeletal muscle but provides only modest improvements in motor function. As strategies to stimulate muscle hypertrophy, such as by myostatin inhibition, have been shown to improve muscle pathology and strength in mouse models of muscular dystrophy, we sought to determine whether these benefits might be similarly realized in Pompe mice. Administration of a recombinant adeno-associated virus serotype 8 vector encoding follistatin, an inhibitor of myostatin, increased muscle mass and strength but only in Pompe mice that were treated before 10 months of age. Younger Pompe mice showed significant muscle fiber hypertrophy in response to treatment with follistatin, but maximal gains in muscle strength were achieved only when concomitant GAA administration reduced glycogen storage in the affected muscles. Despite increased grip strength, follistatin treatment failed to improve rotarod performance. These findings highlight the importance of treating Pompe skeletal muscle before pathology becomes irreversible, and suggest that adjunctive therapies may not be effective without first clearing skeletal muscle glycogen storage with GAA.

Measurement of Soot Surface Growth Kinetics

Surface growth is one of the major steps in the soot formation processes where most of the total mass is formed. Freshly generated soot from an ethylene diffusion flame was sampled and mixed with ethylene in a flow tube at elevated temperatures and using nitrogen as the carrier gas. The changes in the size of the soot particles after hydrocarbon addition were measured using a differential mobility analyzer. These measurements showed a significant mass increase of soot particles as a result of the hydrocarbon addition where the total number density remained the same. Soot surface growth kinetics were obtained from the changes in the size, surface area and volume distributions. The activation energy (Ea) for ethylene was obtained. Pure pyrolysis experiments for ethylene were also performed. The surface growth process yield was found to be higher than the yield of the pyrolysis process.

Growth of Structure Seeded by Primordial Black Holes

We discuss the possibilities for primordial black holes (PBHs) to grow via the accretion of dark matter. In agreement with previous works, we find that accretion during the radiation-dominated era does not lead to a significant mass increase. However, during matter-domination, PBHs may grow by up to two orders of magnitude in mass through the acquisition of large dark matter halos. We discuss the possibility of PBHs being an important component in dark matter halos of galaxies as well as their potential to explain the ultra-luminous x-ray sources (ULXs) observed in nearby galactic disks. We point out that although PBHs are ruled out as the dominant component of dark matter, there is still a great deal of parameter space open to them playing a role in the modern-day universe. For example, a primordial halo population of PBHs each at $10^{2.5} M_\odot$ making up 0.1% of the dark matter grow to $10^{4.5} M_\odot$ via the accumulation of dark matter halos to account for $\sim 10%$ of the dark matter mass by a redshift of $z \approx 30$. These intermediate mass black holes may then ``light up'' when passing through molecular clouds, becoming visible as ULXs at the present day, or they may form the seeds for supermassive black holes at the centers of galaxies.

Disproportionation of stoichiometric LiMn 2O 4 on annealing in oxygen

The evolution of stoichiometric LiMn 2O 4 upon annealing under oxygen pressures in the range 0.2–5 atm at moderate temperature (450°C) was studied with a combination of thermogravimetry, X-ray and neutron diffraction. It is shown that such treatments result in a slight, but significant mass increase. Structural analyses show that the resulting spinel is a manganese-deficient spinel phase with lower cell parameter and higher manganese valence, and that the expelled manganese forms Mn 2O 3. The presence of this second phase, which was not identified in a recent study of oxygen annealing on this compound (Nakamura and Kajiyama, Solid State Ionics 133 (2000) 195), is compatible with the initial stoichiometry and does not require any oxygen vacancies in the initial LiMn 2O 4, as supposed earlier. The most likely formula of the resulting lithium-rich spinel with increased manganese valence is Li(Mn 2− ε □ ε )O 4 with ε in the range 0.02–0.03 at 5 atm O 2.

Qualitative determination of early Maillard-products by MALDI-TOF mass spectrometry peptide mapping

Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) was used to qualitatively study the formation of early Maillard products of lysozyme, produced upon incubation with seven different sugars (D-ribose, L-rhamnose, D-glucose, D-fructose, D-galactose, D-lactose, D-maltose) in solution, in the presence of oxygen. MALDI-TOF mass spectra of intact lysozyme revealed a heterogeneous distribution of glycation products, detected by significant mass increase and peak broadening. Therefore, to get more detailed information about the nature of the glycation products, we performed MALDI-TOF MS peptide mapping analysis. In each of the peptide mapping spectra we were able to detect the early glycation products (Amadori products/glucosylamines) with high selectivity. We were able to distinguish between the Amadori products of the different sugars, due to the characteristic mass increases of the glycated peptides. Furthermore, variations of the modification pattern were observed, very likely due to the different relativities of the seven reducing sugars. Other, more advanced glycation products of the initially formed Maillard products were also detected. Further studies regarding the nature of these late Maillard products are in progress. Here we report, for the first time, the use of MALDI-TOF MS peptide mapping as a quick and highly selective method for the detection of early stage Maillard products produced upon incubation of lysozyme with seven different reducing sugars.

Influence of pH and storage time on the sorption and solubility behaviour of three composite resin materials

Objectives: The aim of this study was to determine whether pH and time has any influence on the sorption and solubility behaviour of composite resin materials stored in a buffer solution. Methods: Three hybrid composite restorative resin materials (Spectrum™, Z-100 ® and ArtGlass™) with different matrix structure and filler composition were studied. One hundred and twenty specimens of each material were produced according to ISO 4049. The materials were stored in McIlvain's buffer solution at different pH (4, 6 and 8) at 1, 7, 60 and 180 days. pH measurements were carried out before and after completed storage. Results: Time had a significant influence on the sorption and solubility behaviour of the composite resin materials tested. One of the materials Z-100 ® showed a significant mass increase and/or decrease depending on the pH of the solution. The material Spectrum™ was significantly influenced by pH, resulting in different sorption depending on the pH of the solution. Conclusions: Time of storage was important for the sorption and solubility behaviour of the composite resin materials tested. Comparison of solubility for one of the materials showed twice as high values in the present study as previously reported when distilled water was used as storage medium. pH in the solution seems to have an influence on the sorption and solubility behaviour of composite resin materials. The sensitivity of the sorption and solubility behaviour to time and pH of the materials tested seems to be related to the hydrophilicity of the matrix and the chemical composition of the filler.

Electrochemical Characterization of Single‐Walled Carbon Nanotube Electrodes

The cyclic voltammetric responses and capacitive behavior of single‐walled carbon nanotube sheets or papers are described. Broad redox responses have been observed in aqueous solutions that are probably due to the presence of oxygen‐containing groups bound to the surface of the nanotubes or to the impurities produced during nanotube purification. The voltammetry and capacitance of the nanotube paper do not vary significantly when the chemical nature of the electrolyte ions is changed. In nonaqueous media, no redox responses are produced except in solutions of , where an intense reduction response, possibly due to lithium insertion into the nanotube bundles, is observed. Electrochemical impedance spectroscopy in aqueous solutions reveals the typical features associated with a porous material. Electrochemical quartz crystal microbalance studies in both aqueous and nonaqueous electrolytes show that the mass of the nanotube film increases as the potential is made more negative. These mass changes are affected by, but are not directly proportional to, the cation mass. In acetonitrile solutions of , a significant increase in mass associated with the suggested insertion of the cation is observed. © 2000 The Electrochemical Society. All rights reserved.

Sexual dimorphism and testosterone responsiveness in hypaxial muscles of the northern leopard frog, Rana pipiens

AbstractAbdominal hypaxial muscles of male anurans function in vocalization by causing forcible expulsion of pulmonary air through the larynx. The hypaxial muscles were studied in the leopard frog, Rana pipiens, to test whether functions of these muscles in males are reflected in sexual dimorphism and in androgen responsiveness. The combined abdominal oblique muscles and the rectus abdominis showed significant sexual dimorphism in wet mass and dry mass. However, the abdominal oblique muscles were less concentrated in protein content in males than in females. In overwintering males, exogenous testosterone cypionate stimulated a significant increase in mass and protein content of the abdominal oblique and rectus abdominis muscles. Castration had no effect on muscle mass or on the response to androgen treatment.

Reinnervation and regeneration of denervated rat soleus muscles.

Muscle atrophy is a serious and sometimes irreversExperiments were approved by the University Committee on Use and Care of Animals. ible consequence of peripheral nerve damage.4 Recently, we found that muscle atrophy is reversible to Four groups of denervated muscles were used in this study. In all groups, the soleus muscles were varying extents when denervated muscles are grafted with nerve implants.4 In that study, rat extensor digdenervated for 2 months. In the first group, the muscles were denervated by cutting the sciatic nerve high itorum longus (EDL) muscles were denervated for 1–12 months. The muscles were then grafted into in the thigh region and then directing the cut ends of the nerve into nearby muscles. This method is innervated sites of host animals. The grafting operation resulted in a significant increase in mass and highly effective in maintaining the denervated state of the crural muscles.4 In the remaining three groups, force-generating ability of the muscles over the denervated state; the degree of improvement was inthe soleus muscles of each animal were locally denervated by the following procedure. The nerve versely proportional to the time of initial denervation. One question to arise from the study was branches innervating each soleus muscle were ligated, cut, and marked with powdered carbon. With whether or not grafting contributed to the functional return of the denervated muscles or if nerve implana needle attached to the ligating suture, the ligated end of the nerve branches was pulled through adjatation alone accounted for the return. To answer this, soleus muscles were denervated and then reincent muscles and then sutured to the lateral aspect of the biceps femoris. After 2 months, the first group nervated with and without concomitant grafting. The soleus, unlike the EDL, can be locally denervated of the locally denervated soleus muscles was removed for comparison with the soleus muscles that were and reinnervated without disturbing its tendons. This study found that 2-month denervated muscles grafted denervated by sciatic nerve section. with nerve implants have a higher mass and generate In the remaining two denervated groups, each sotwice the force of that generated by denervated musleus muscle was reinnervated by implanting its origicles which receive nerve implants but are not grafted. nal nerve into the muscle. Each nerve was cut free of its attachment to the biceps femoris and then imMETHODS planted into the soleus muscle with forceps. In one Experiments were performed on 34 highly inbred, of these two groups, the soleus muscles were orthoconventionally held, 3 1/2–4-month-old, male WI/ topically autografted prior to receiving nerve imHicksCar rats. The rats were anesthetized with ether plants. In the other group, the soleus muscles reduring surgery and sacrificed with ether overdose. ceived nerve implants but were not grafted. Controls of these groups were age-matched, normal intact soleus muscles. *Correspondence to: Dr. Lynn Billington Contract grant sponsor: NIH; Contract grant number: PO1 AG-10821 Physiology. Contractile property measurements CCC 0148-639X/97/060740-04  1997 John Wiley & Sons, Inc. were performed in vitro according to the methods