Neurobiological mechanisms of TENS-induced analgesia.

Pain inhibition by additional somatosensory input is the rationale for the widespread use of Transcutaneous Electrical Nerve Stimulation (TENS) to relieve pain. Two main types of TENS produce analgesia in animal models: high-frequency (∼50-100 Hz) and low-intensity 'conventional' TENS, and low-frequency (∼2-4 Hz) and high-intensity 'acupuncture-like' TENS. However, TENS efficacy in human participants is debated, raising the question of whether the analgesic mechanisms identified in animal models are valid in humans. Here, we used a sham-controlled experimental design to clarify the efficacy and the neurobiological effects of 'conventional' and 'acupuncture-like' TENS in 80 human volunteers. To test the analgesic effect of TENS we recorded the perceptual and brain responses elicited by radiant heat laser pulses that activate selectively Aδ and C cutaneous nociceptors. To test whether TENS has a long-lasting effect on brain state we recorded spontaneous electrocortical oscillations. The analgesic effect of 'conventional' TENS was maximal when nociceptive stimuli were delivered homotopically, to the same hand that received the TENS. In contrast, 'acupuncture-like' TENS produced a spatially-diffuse analgesic effect, coupled with long-lasting changes both in the state of the primary sensorimotor cortex (S1/M1) and in the functional connectivity between S1/M1 and the medial prefrontal cortex, a core region in the descending pain inhibitory system. These results demonstrate that 'conventional' and 'acupuncture-like' TENS have different analgesic effects, which are mediated by different neurobiological mechanisms.

High non-esterified fatty acid concentrations promote expression and secretion of fibroblast growth factor 21 in calf hepatocytes cultured in vitro.

Negative energy balance is considered as the pathological basis of energy metabolic disorders in periparturient dairy cows. Serum non-esterified fatty acids (NEFA) are one of the most important indicators of energy balance status. Fibroblast growth factor 21 (FGF21) has been identified as a hepatokine involved in regulation of metabolic adaptations, such as promoting hepatic lipid oxidation and ketogenesis, during energy deprivation. However, the direct effects of NEFA on FGF21 expression and secretion in bovine hepatocytes are not entirely clear. The objective of this study was to investigate the effects of different NEFA concentrations on FGF21 expression and secretion in calf hepatocytes cultured in vitro. NEFA were added to the culture solution at final concentrations of 0.6, 1.2, 1.8 and 2.4 mmol/L. After 24 hr of continuous culture, FGF21 mRNA and protein expression levels in the hepatocytes were determined by real-time PCR and Western blot respectively. FGF21 secretion in the supernatant was determined by enzyme-linked immunosorbent assay (ELISA). The results showed that expression and secretion of FGF21 at 0.6 mmol/L NEFA-treated hepatocytes was higher than that of the control group (p < .05). The FGF21 expression and secretion were similar at 1.2, 1.8 and 2.4 mmol/L NEFA-treated hepatocytes and significantly higher than those observed for controls (p < .01). These data suggest that high concentrations of NEFA significantly promote FGF21 expression and secretion in bovine hepatocytes. In particular, this promotion occurs in a dose-dependent manner and may be involved in the pathological processes of energy metabolism disorders of dairy cows in the peripartum period.

Note: A monoenergetic proton backlighter for the National Ignition Facility.

A monoenergetic, isotropic proton source suitable for proton radiography applications has been demonstrated at the National Ignition Facility (NIF). A deuterium and helium-3 gas-filled glass capsule was imploded with 39 kJ of laser energy from 24 of NIF's 192 beams. Spectral, spatial, and temporal measurements of the 15-MeV proton product of the (3)He(d,p)(4)He nuclear reaction reveal a bright (10(10) protons/sphere), monoenergetic (ΔE/E = 4%) spectrum with a compact size (80 µm) and isotropic emission (∼13% proton fluence variation and <0.4% mean energy variation). Simultaneous measurements of products produced by the D(d,p)T and D(d,n)(3)He reactions also show 2 × 10(10) isotropically distributed 3-MeV protons.

[Studies on the photosynthetic characteristics of wheat variants by introduction sorghum DNA].

Spring wheat Longchun No. 13 and Ganmai No. 8 were introduced by sorghum DNA via pollen tube pathway, and two stable progenies (89,122 and 89,144 respectively) were obtained through selection for several years. The results of photosynthetic analysis showed that photosynthetic rate (P) and photosynthetic/transpiration rate (E/P) of 89,122 and 89,144 were mediated between their recipients and donor respectively, which demonstrated stronger photosynthetic efficiency than their receptors. However, the delta 13 C values in assimilates from 89,122, 89,144 and their maternal wheat cultivars G8 and L13 were approximately same, and they were significant different from sorghum. The chlorophyll content and the ratio of Chla/Chlb of them also showed that wheat cultivars and sorghum were different. It might demonstrated that the stronger photosynthetic efficiency of the progenies was due to their higher Calvin cycle metabolism efficiency rather than their carbon-fixation pathway difference. On the other hand, it also suggested that the distant genetic materials of the sorghum affected the photosynthetic characteristics of 89122 and 89144.