1,409 research outputs found
A glycinergic projection from the ventromedial lower brainstem to spinal motoneurons. An ultrastructural double labeling study in rat
__Abstract__
In the present study it was determined whether glycine was present in the descending brainstem projections to spinal motoneurons in the rat. For this purpose injections of wheatgerm agglutinin-horseradish peroxidase (WGA-HRP) were made in the ventromedial part of the lower brainstem at the levels of the rostral inferior olive and the caudal facial nucleus. After perfusion, WGA-HRP histochemistry was performed, followed by the postembedding immunogold tehncque with an antbody against glycine. Electron microscopical examination of the lumbar motoneuronal cell groups showed that 15% of the WGA-HRP labeled terminals, derived from the ventromedial reticular formation, were also labeled for glycine. The majority (91%) of these double labeled terminal were of the F-type (containing many flattened vesicles), while the remaining 9% were of the S-type (containing mostly sphetical vesicles). Many of the double labeled terminals established a synapse, mostly with proximal and distal dendrites. The present data, combined with our previous findings that 40% of the projections from the same ventromedial brainstem area to lumbar motoneurons contained γ-aminobutyric acid (GABA), indicate that over 50% of these brainstem projections contain GABA and/or glycine, exerting a direct inhibition effect on spinal motoneurons. The possibility that the glycinergic fibers within these projections play an important role in producing muscle atonia during rapid eye movement (REM) sleep is discussed
Multiple solutions of the quasirelativistic Choquard equation
We prove existence of multiple solutions to the quasirelativistic Choquard equation with a scalar potential
A multifrequency notch filter for millimeter wave plasma diagnostics based on photonic bandgaps on corrugated circular waveguides
Sensitive millimeter wave diagnostics need often to be protected against unwanted radiation like, for example, stray radiation from high power Electron Cyclotron Heating applied in nuclear fusion plasmas. A notch filter based on a waveguide Bragg reflector (photonic band-gap) may provide several stop bands of defined width within up to two standard waveguide frequency bands. A Bragg reflector that reflects an incident fundamental TE11 into a TM1n mode close to cutoff is combined with two waveguide tapers to fundamental waveguide diameter. Here the fundamental TE11 mode is the only propagating mode at both ends of the reflector. The incident TE11 mode couples through the taper and is converted to the high order TM1n mode by the Bragg structure at the specific Bragg resonances. The TM1n mode is trapped in the oversized waveguide section by the tapers. Once reflected at the input taper it will be converted back into the TE11 mode which then can pass through the taper. Therefore at higher order Bragg resonances, the filter acts as a reflector for the incoming TE11 mode. Outside of the Bragg resonances the TE11 mode can propagate through the oversized waveguide structure with only very small Ohmic attenuation compared to propagating in a fundamental waveguide. Coupling to other modes is negligible in the non-resonant case due to the small corrugation amplitude (typically 0.05·λ0, where λ0 is the free space wavelength). A Bragg reflector for 105 and 140 GHz was optimized by mode matching (scattering matrix) simulations and manufactured by SWISSto12 SA, where the required mechanical accuracy of ± 5 μm could be achieved by stacking stainless steel rings, manufactured by micro-machining, in a high precision guiding pipe. The two smooth-wall tapers were fabricated by electroforming. Several measurements were performed using vector network analyzers from Agilent (E8362B), ABmm (MVNA 8-350) and Rohde&Schwarz (ZVA24) together with frequency multipliers. The stop bands around 105 GHz (- 55dB) and 140 GHz (-60dB) correspond to the TE11-TM12 and TE11-TM13 Bragg resonances. Experiments are in good agreement with theory
Performance Benefits of Pre- and Per-cooling on Self-paced Versus Constant Workload Exercise:A Systematic Review and Meta-analysis
BACKGROUND AND OBJECTIVE: Exercise in hot environments impairs endurance performance. Cooling interventions can attenuate the impact of heat stress on performance, but the influence of an exercise protocol on the magnitude of performance benefit remains unknown. This meta-analytical review compared the effects of pre- and per-cooling interventions on performance during self-paced and constant workload exercise in the heat.METHODS: The study protocol was preregistered at the Open Science Framework ( https://osf.io/wqjb3 ). A systematic literature search was performed in PubMed, Web of Science, and MEDLINE from inception to 9 June, 2023. We included studies that examined the effects of pre- or per-cooling on exercise performance in male individuals under heat stress (> 30 °C) during self-paced or constant workload exercise in cross-over design studies. Risk of bias was assessed using the Cochrane Risk of Bias Tool for randomized trials.RESULTS: Fifty-nine studies (n = 563 athletes) were identified from 3300 records, of which 40 (n = 370 athletes) used a self-paced protocol and 19 (n = 193 athletes) used a constant workload protocol. Eighteen studies compared multiple cooling interventions and were included more than once (total n = 86 experiments and n = 832 paired measurements). Sixty-seven experiments used a pre-cooling intervention and 19 used a per-cooling intervention. Average ambient conditions were 34.0 °C [32.3-35.0 °C] and 50.0% [40.0-55.3%] relative humidity. Cooling interventions attenuated the performance decline in hot conditions and were more effective during a constant workload (effect size [ES] = 0.62, 95% confidence interval [CI] 0.44-0.81) compared with self-paced exercise (ES = 0.30, 95% CI 0.18-0.42, p = 0.004). A difference in performance outcomes between protocols was only observed with pre-cooling (ES = 0.74, 95% CI 0.50-0.98 vs ES = 0.29, 95% CI 0.17-0.42, p = 0.001), but not per-cooling (ES = 0.45, 95% CI 0.16-0.74 vs ES = 0.35, 95% CI 0.01-0.70, p = 0.68).CONCLUSIONS: Cooling interventions attenuated the decline in performance during exercise in the heat, but the magnitude of the effect is dependent on exercise protocol (self-paced vs constant workload) and cooling type (pre- vs per-cooling). Pre-cooling appears to be more effective in attenuating the decline in exercise performance during a constant workload compared with self-paced exercise protocols, whereas no differences were found in the effectiveness of per-cooling.</p
Qualitative welfare risks of cows offered to a Dutch mobile slaughter unit
In the Netherlands, a pilot was initiated of a mobile slaughter unit (MSU) for the killing of cull dairy cattle not fit for transport but suitable for slaughter, in order to save valuable meat. The Office for Risk Assessment & Research (BuRO) was asked to assess the risks for animal welfare. As a thorough risk assessment would have been very time consuming, a qualitative framework was used instead. The goal of the current study was to qualitatively describe the relevant risks for cow welfare involved in the use of an MSU compared with current practice by carrying out a rapid comparative risk assessment of animal welfare. The assessment framework consisted of the following steps: identification and description of scenarios, followed by assessment and comparison of the most relevant animal welfare risks in these scenarios, including hazard identification, hazard characterization, exposure, and characterization of the risk to animal welfare. Two main scenarios were identified, one with and one without an MSU. The second scenario was split into three sub-scenarios: killing on the farm/in a housing unit, emergency slaughter, and conventional transport to the slaughterhouse. The most relevant risks associated with operating an MSU were as follows: leaving the cow alive on the farm when it was not fit for slaughter; forcing the cow to walk to and into the MSU (however, this risk is likely higher under conventional transport of unfit cows); and insufficient stunning and bleeding, leading to questionable unconsciousness (however, this risk is likely higher in an emergency slaughter scenario). The MSU is a means of preventing the exacerbation of welfare deterioration in cows that are unfit for transport but fit for slaughter, and it reduces exposure to stressors (hazards) that are conventionally present during transport and at a stationary slaughterhouse. This rapid comparative risk assessment of animal welfare supported swift decision-making: the national competent authority (i.e., the NVWA in the Netherlands) and policymakers were able to improve and develop risk-mitigating actions and to decide on allowing the use of an MSU. When appropriately designed and used, and with sufficient supervision, mobile slaughter facilities can reduce welfare risks in cull dairy cows that are unfit for transport but fit for slaughter
Mean-field Study of Charge, Spin, and Orbital Orderings in Triangular-lattice Compounds ANiO2 (A=Na, Li, Ag)
We present our theoretical results on the ground states in layered
triangular-lattice compounds ANiO2 (A=Na, Li, Ag). To describe the interplay
between charge, spin, orbital, and lattice degrees of freedom in these
materials, we study a doubly-degenerate Hubbard model with electron-phonon
couplings by the Hartree-Fock approximation combined with the adiabatic
approximation. In a weakly-correlated region, we find a metallic state
accompanied by \sqroot3x\sqroot3 charge ordering. On the other hand, we obtain
an insulating phase with spin-ferro and orbital-ferro ordering in a wide range
from intermediate to strong correlation. These phases share many
characteristics with the low-temperature states of AgNiO2 and NaNiO2,
respectively. The charge-ordered metallic phase is stabilized by a compromise
between Coulomb repulsions and effective attractive interactions originating
from the breathing-type electronphonon coupling as well as the Hund's-rule
coupling. The spin-orbital-ordered insulating phase is stabilized by the
cooperative effect of electron correlations and the Jahn-Teller coupling, while
the Hund's-rule coupling also plays a role in the competition with other
orbital-ordered phases. The results suggest a unified way of understanding a
variety of low-temperature phases in ANiO2. We also discuss a keen competition
among different spin-orbital-ordered phases in relation to a puzzling behavior
observed in LiNiO2
Implications of thermo-chemical instability on the contracted modes in CO2 microwave plasmas
Understanding and controlling contraction phenomena of plasmas in reactive flows is essential to optimize the discharge parameters for plasma processing applications such as fuel reforming and gas conversion. In this work, we describe the characteristic discharge modes in a CO2 microwave plasma and assess the impact of wave coupling and thermal reactivity on the contraction dynamics. The plasma shape and gas temperature are obtained from the emission profile and the Doppler broadening of the 777 nm O(5S ← 5P) oxygen triplet, respectively. Based on these observations, three distinct discharge modes are identified in the pressure range of 10 mbar to atmospheric pressure. We find that discharge contraction is suppressed by an absorption cut-off of the microwave field at the critical electron density, resulting in a homogeneous discharge mode below the critical transition pressure of 85 mbar. Further increase in the pressure leads to two contracted discharge modes, one emerging at a temperature of 3000 K to 4000 K and one at a temperature of 6000 K to 7000 K, which correspond to the thermal dissociation thresholds of CO2 and CO respectively. The transition dynamics are explained by a thermo-chemical instability, which arises from the coupling of the thermal-ionization instability to heat transfer resulting from thermally driven endothermic CO2 dissociation reactions. These results highlight the impact of thermal chemistry on the contraction dynamics of reactive molecular plasmas.</p
Elucidating the role of gas dynamics in the vortex-confined microwave plasma on CO2 dissociation efficiency
Individualized Positron Emission Tomography-Based Isotoxic Accelerated Radiation Therapy Is Cost-Effective Compared With Conventional Radiation Therapy: A Model-Based Evaluation
Purpose: To evaluate long-term health effects, costs, and cost-effectiveness of positron emission tomography (PET)-based isotoxic accelerated radiation therapy treatment (PET-ART) compared with conventional fixed-dose CT-based radiation therapy treatment (CRT) in non-small cell lung cancer (NSCLC). Methods and Materials: Our analysis uses a validated decision-model, based on data of 200 NSCLC patients with inoperable stage I-IIIB. Clinical outcomes, resource use, costs, and utilities were obtained from the Maastro Clinic and the literature. Primary model outcomes were the difference in life-years (LYs), quality-adjusted life-years (QALYs), costs, and the incremental cost-effectiveness and cost/utility ratio (ICER and ICUR) of PET-ART versus CRT. Model outcomes were obtained from averaging the predictions for 50,000 simulated patients. A probabilistic sensitivity analysis and scenario analyses were carried out. Results: The average incremental costs per patient of PET-ART were V569 (95% confidence interval [CI] (sic)-5327-(sic)6936) for 0.42 incremental LYs (95% CI 0.19-0.61) and 0.33 QALYs gained (95% CI 0.13-0.49). The base-case scenario resulted in an ICER of (sic)1360 per LY gained and an ICUR of (sic)1744 per QALY gained. The probabilistic analysis gave a 36% probability that PET-ART improves health outcomes at reduced costs and a 64% probability that PET-ART is more effective at slightly higher costs. Conclusion: On the basis of the available data, individualized PET-ART for NSCLC seems to be cost-effective compared with CRT
Transport properties of Layer-Antiferromagnet CuCrS2: A possible thermoelectric material
The electrical, thermal conductivity and Seebeck coefficient of the quenched,
annealed and slowly cooled phases of the layer compound CuCrS2 have been
reported between 15K to 300K. We also confirm the antiferromagnetic transition
at 40K in them by our magnetic measurements between 2K and 300K. The crystal
flakes show a minimum around 100K in their in-plane resistance behavior. For
the polycrystalline pellets the resistivity depends on their flaky texture and
it attains at most 10 to 20 times of the room temperature value at the lowest
temperature of measurement. The temperature dependence is complex and no
definite activation energy of electronic conduction can be discerned. We find
that the Seebeck coefficient is between 200-450 microV/K and is unusually large
for the observed resistivity values of between 5-100 mOhm-cm at room
temperature. The figure of merit ZT for the thermoelectric application is 2.3
for our quenched phases, which is much larger than 1 for useful materials. The
thermal conductivity K is mostly due to lattice conduction and is reduced by
the disorder in Cu- occupancy in our quenched phase. A dramatic reduction of
electrical and thermal conductivity is found as the antiferromagnetic
transition is approached from the paramagnetic region, and K subsequently rises
in the ordered phase. We discuss the transport properties as being similar to a
doped Kondo-insulator
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