1,756 research outputs found

    Regulation of Rabbit Testicular Capsular Motility: The Interaction of Prostaglandins, Acetylcholine and Sympathomimetic Agents

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    The regulation of the contractility and intratesticular pressure of rabbit testes was studied. The effects of, and interactions among, prostaglandins (PGs) E1 and F2Ξ± testosterone, acetylcholine, epinephrine and norepinephrine were ascertained both in vitro and in vivo. All of these compounds, except for high concentrations of PGE1 and testosterone, stimulated the testicular capsule to contract. PGE1 at low concentrations potentiated the contractions produced by epinephrine and acetylcholine. Above 10-7M, PGE1 inhibited contractions caused by PGF2Ξ± epinephrine or acetylcholine. Testosterone inhibited contractions caused by PGF2Ξ± in vitro. Preinjections of rabbits with the PG synthetase inhibitor, indomethacin, significantly reduced testicular contractility in vivo. A second inhibitor of PG synthetase, 5,8,11,14-eicosatetraynoic acid (TYA), had no such effect. Reserpine failed to alter testicular contractions in vivo. Attempts to stimulate the spermatic nerve electrically using Ag-AgCl electrodes did not alter intratesticular pressure. Exposing male rabbits to females had no significant effect on testicular contractions in vivo or in vitro. Serum testosterone measurements were made after injections of indomethacin, TVA, reserpine and combinations of indomethacin and PGE1. No significant changes were noted among groups due to large variability. Intratesticular pressure showed spontaneous, rhythmical fluctuations in some preparations. Intravenous injections of norepinephrine increased overall pressure, whereas isoproterenol decreased it. The inhibition of rhythmical pressure changes after iv infusion of isoproterenol persisted at least half an hour. During this time norepinephrine failed to increase intratesticular pressure

    Is the even distribution of insecticide-treated cattle essential for tsetse control? Modelling the impact of baits in heterogeneous environments

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    Background: Eliminating Rhodesian sleeping sickness, the zoonotic form of Human African Trypanosomiasis, can be achieved only through interventions against the vectors, species of tsetse (Glossina). The use of insecticide-treated cattle is the most cost-effective method of controlling tsetse but its impact might be compromised by the patchy distribution of livestock. A deterministic simulation model was used to analyse the effects of spatial heterogeneities in habitat and baits (insecticide-treated cattle and targets) on the distribution and abundance of tsetse. Methodology/Principal Findings: The simulated area comprised an operational block extending 32 km from an area of good habitat from which tsetse might invade. Within the operational block, habitat comprised good areas mixed with poor ones where survival probabilities and population densities were lower. In good habitat, the natural daily mortalities of adults averaged 6.14% for males and 3.07% for females; the population grew 8.46in a year following a 90% reduction in densities of adults and pupae, but expired when the population density of males was reduced to <0.1/km2; daily movement of adults averaged 249 m for males and 367 m for females. Baits were placed throughout the operational area, or patchily to simulate uneven distributions of cattle and targets. Gaps of 2–3 km between baits were inconsequential provided the average imposed mortality per km2 across the entire operational area was maintained. Leaving gaps 5–7 km wide inside an area where baits killed 10% per day delayed effective control by 4–11 years. Corrective measures that put a few baits within the gaps were more effective than deploying extra baits on the edges. Conclusions/Significance: The uneven distribution of cattle within settled areas is unlikely to compromise the impact of insecticide-treated cattle on tsetse. However, where areas of >3 km wide are cattle-free then insecticide-treated targets should be deployed to compensate for the lack of cattle

    Method and Apparatus for Utilizing Amplitude-Modulated Pulse-Width Modulation Signals for Neurostimulation and Treatment of Neurological Disorders Using Electrical Stimulation

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    A computing device-controlled system is described for the generation of amplitude-modulated pulse-width modulation (AMPWM) signals for use in treating neurological dysfunction via cranial neurostimulation, where the AMPWM signal is specifically designed to minimize the electrical impedance of the tissues of the head. A low-frequency carrier signal is determined for the AMPWM signal by measuring EEG activity at a reference site or sites, generally corresponding with the location of suspected brain dysfunction. Carrier signal frequency is variably related to critical frequency components of the EEG power spectral density, determined from statistical analysis of amplitudes and variability, and dynamically changed as a function of time to prevent entrainment. The AMPWM signal is presented to a subject via a plurality of neurostimulation delivery modes for therapeutic use

    Housing Cost Burden and Maternal Stress among Very Low Income Mothers

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    As the affordable housing shortage proliferates, more American households struggle with high housing cost burdens. Grounded in Belsky’s (1984) parenting stress framework, we use a weighted low-income sample from the Fragile Families and Child Wellbeing Study of mothers who rent their homes (N=388) to investigate a relationship between housing cost burden, or paying a substantial portion of income toward housing, and higher rates of reported maternal stress. Findings of the linear regression indicate that younger mothers and those paying 30% or more of their income each month toward rent have higher reported maternal stress scores. These findings are discussed with attention to practice and policy implications

    Preliminary results toward continuous and proportional control of a multi-synergistic soft prosthetic hand

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    State of art of modern hand prosthesis is populated by sophisticate hi-tech poly-articular hands which usually offer a broader set of movement capabilities, with the possibility to control up to 4 or 5 motors and achieve several different postures. Unfortunately these device are not so easy to control. A novel emerging trend is oriented towards a strong simplification of the mechanical design (through i.e. underactuation mechanisms), but still maintaining a good level of performance. A successful example is the SoftHand2 Pro, a 19 Degrees of Freedom (DoF) anthropomorphic hand which, using two motors, can move along two different synergistic directions, to perform either power grasp, precision grasp and index point. The combination of this multi-synergistic prosthetic hand with advanced controls, as myoelectric pattern recognition algorithms, allows to get promising results toward a more natural and intuitive control, introducing novel features as the possibility of a continuous switch between gestures. Preliminary experimental results are presented, demonstrating the effectiveness of the idea

    Measurement of electron screening in muonic lead

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    Energies of the transitions between high-lying (nβ‰₯6) states of muonic lead were accurately determined. The results are interpreted as a ∼2% test of the electron screening. The agreement between experiment and theory is good if it is assumed that the refilling of the electron K shell is fast. The present results furthermore severely restrict possible ionization of the electron L shell

    Modeling the Control of Trypanosomiasis Using Trypanocides or Insecticide-Treated Livestock

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    In Uganda, cattle are an important reservoir for Trypanosoma brucei rhodesiense, the causative agent of Rhodesian sleeping sickness (human African trypanosomiasis), transmitted by tsetse flies Glossina fuscipes fuscipes, which feed on cattle, humans, and wild vertebrates, particularly monitor lizards. Trypanosomiasis can be controlled by treating livestock with trypanocides or insecticide – killing parasites or vectors, respectively. Mathematical modeling of trypanosomiasis was used to compare the impact of drug- and insecticide-based interventions on R0 with varying densities of cattle, humans and wild hosts. Intervention impact changes with the number of cattle treated and the proportion of bloodmeals tsetse take from cattle. R0 was always reduced more by treating cattle with insecticide rather than trypanocides. In the absence of wild hosts, the model suggests that control of sleeping sickness (R0<1) could be achieved by treating ∼65% of cattle with trypanocides or ∼20% with insecticide. Required coverage increases as wild mammals provide increasing proportion of tsetse bloodmeals: if 60% of non-human bloodmeals are from wild hosts then all cattle have to be treated with insecticide. Conversely, it is reduced if lizards, which do not harbor trypanosomes, are important hosts and/or if insecticides are used at a scale where tsetse numbers decline

    Topical anti-inflammatory activity of Polygonum cuspidatum extract in the TPA model of mouse ear inflammation

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    <p>Abstract</p> <p>Background</p> <p>This study tested the ability of a characterized extract of <it>Polygonum cuspidatum </it>(PCE) to inhibit mouse ear inflammation in response to topical application of 12-<it>O-</it>tetradecanoylphorbol-13-acetate (TPA).</p> <p>Methods</p> <p>A 50% (wt:vol) ethanolic solution of commercial 200:1 PCE was applied to both ears of female Swiss mice (n = 8) at 0.075, 0.15, 0.3, 1.25 and 2.5 mg/ear 30 min after TPA administration (2 ΞΌg/ear). For comparison, 3 other groups were treated with TPA and either 1) the vehicle (50% ethanol) alone, 2) indomethacin (0.5 mg/ear), or 3) <it>trans</it>-resveratrol (0.62 mg/ear). Ear thickness was measured before TPA and at 4 and 24 h post-TPA administration to assess ear edema. Ear punch biopsies were collected at 24 h and weighed as a second index of edema. Myeloperoxidase activity was measured in each ear punch biopsy to assess neutrophil infiltration.</p> <p>Results</p> <p>PCE treatment at all doses significantly reduced ear edema compared to the TPA control. The PCE response was dose-dependent and 2.5 mg PCE significantly inhibited all markers of inflammation to a greater extent than indomethacin (0.5 mg). MPO activity was inhibited at PCE doses β‰₯ 1.25 mg/ear. <it>Trans-</it>resveratrol inhibited inflammation at comparable doses.</p> <p>Conclusion</p> <p>PCE inhibits development of edema and neutrophil infiltration in the TPA-treated mouse ear model of topical inflammation.</p

    Heritability of Clinical Mastitis Incidence and Relationships with Sire Transmitting Abilities for Somatic Cell Score, Udder Type Traits, Productive Life, and Protein Yield

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    The objective of this study was to determine the relationships among daughter clinical mastitis during first and second lactations and sire transmitting abilities for somatic cell score, udder type traits, productive life, and protein yield. Data on clinical mastitis during first lactation were available for 1795 daughters (in six Pennsylvania herds, one Minnesota herd, and one Nebraska herd) of 283 Holstein sires. Data on clinical mastitis during second lactation were available for 1055 of these daughters. A total of 479 cows had 864 clinical episodes during first lactation, and 230 cows had 384 clinical episodes during second lactation. Clinical mastitis incidence and the total number of clinical episodes during each lactation were regressed on herd-season of calving (a classification variable), age at first calving, lactation length, and sire transmitting abilities taken one at a time. Linear effects, nonlinear effects, and odds ratios were estimated for sire transmitting abilities. Separate analyses were conducted on dependent variables that considered clinical mastitis from: all organisms, coagulase-negative staphylococci, coliform species, streptococci other than Streptococcus agalactiae, and the most common environmental organisms (coliform species and streptococci other than Streptococcus agalactiae). Heritability of clinical mastitis ranged from 0.01 to 0.42. Daughters of sires that transmit the lowest somatic cell score had the lowest incidence of clinical mastitis and the fewest clinical episodes during first and second lactations. Daughters of sires that transmit longer productive life, shallower udders, deeper udder cleft, and strongly attached fore udders had either fewer clinical episodes or lower clinical mastitis incidence during first and second lactations. The incidence of clinical mastitis and the number of clinical episodes per lactation may be reduced by selection for lower somatic cell score, longer productive life, shallower udders, deeper udder cleft, or strongly attached fore udders
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