Polarized XRF Spectrometer with a 40-mW X-Ray Tube

A three-dimensional polarized X-ray fluorescence (XRF) spectrometer was assembled with a low-power X-ray tube of 40 milliwatts, and a sample of stainless steel was measured with an acrylic polarizer. Based on the Schr?dinger’s wave picture of Compton scattering, the dependence of the de Broglie wavelength and the scattering angle of a recoil electron on the incident X-ray energy were calculated. When the incident X-rays were scattered at an angle of 90°, the de Broglie of the recoil electron always went away at an angle of 45° with the incident X-rays and the de Broglie wavelength varied for any wavelength of the incident X-rays, i.e. we could select the scattering angle of the recoil electron to be 45°according to the incident X-ray energy and it could then be regarded as 45° Bragg diffraction that could produce highly polarized X-rays. The polarization measurement of scattered X-rays from an acrylic and lead plates substantiated that Compton scattered X-rays from the acrylic plate had higher degree of polarization than the elastically scattered X-rays from the lead plate. Highly polarized Compton scattered X-rays from the light-element polarizer led to the background reduction and the changes of the characteristic X-ray intensity in XRF spectra measured by our laboratory-made spectrometer.Трехмерный рентгеновский флуоресцентный спектрометр с поляризатором (РФА) был собран с использованием маломощной рентгеновской трубки. Размер спектрометра составлял 25 см в длину, ширина и высота по 10 см. Расстояние от рентгеновской трубки до поляризатора составляло 10 мм, между образцом и детектором ? 10 мм. Камера образцов не вакуумировалась. Образец устанавливали на дно акрилового блока. Рентгеновское излучение падало на поляризатор под углом 45? , и после отражения направлялось на образец под углом в 45? . Использовали рентгеновскую трубку с вольфрамовым анодом фирмы Moxtek (номинальная мощность 4 Вт, максимальное напряжение 50 кВ). В качестве поляризатора использовали акриловую (C5H2 O8 )n пластину площадью 80 мм2 и толщиной 30 мм. Излучение регистрировали детектором SDD (RES-Lab, Osaka) площадью 100 мм2 , толщина кремниевого кристалла составляла 450 мкм. Толщина бериллиевого окна ? 8 мкм. Холодильник Пельтье понижал температуру детектора до -30 ° С. Образец из нержавеющей стали измеряли c акриловым поляризатором. На основе волновой теории Шредингера комптоновского рассеяния рассчитана зависимость длины волны де Бройля и угла рассеяния электрона отдачи в зависимости от энергии падающего рентгеновского излучения. Измерение поляризации рассеянного рентгеновского излучения подтвердило, что некогерентно рассеянное на акриловой пластинке рентгеновское излучение имело более высокую степень поляризации, чем когерентно рассеянное рентгеновское излучение от свинцовой пластины. Высокополяризованное некогерентно рассеянное рентгеновское излучение от поляризатора из элемента с малым атомным номером привело к уменьшению фона и изменению интенсивности характеристического рентгеновского излучения в РФА спектрах, измеренных нашим лабораторным спектрометром

TONS504-PHOTODYNAMIC THERAPY INDUCES CYTOTOXIC EFFECTS IN EMT6 CELLS

In the present study, TONS504 (C51H58N8O5I2; molecular weight, 1,116.9), a novel cationic hydrophilic photosensitizer, was synthesized from protoporphyrin IX dimethyl ester through a five‑step process according to a patented method for use in photodynamic therapy (PDT). The subcellular localization of TONS504 and the cytotoxic effects of TONS504‑mediated PDT in the mouse mammary tumor EMT6 cell line were investigated. TONS504 was localized primarily in the lysosomes and partially in the mitochondria. The cytotoxic effects of TONS504‑mediated PDT in the mouse mammary tumor EMT6 cell line were investigated using a WST8 assay and an Oxidative Stress kit. The cell viability values following treatment with 10 µg/ml TONS504 at light energies of 0, 1, 5 and 10 J/cm2 were 92.5, 101.8, 27.7 and 1.8%, respectively. The percentages of reactive oxygen species (ROS)(+) cells following the same treatment were 8.6, 8.5, 29.2 and 70.1%, respectively, whereas the percentages of apoptotic cells were 7.1, 5.6, 24.8 and 48.7%, respectively. The percentages of ROS(+) and apoptotic cells in the group subjected to TONS504‑mediated PDT increased in a manner dependent on the TONS504 concentration and light energy. Further studies are required to evaluate the in vivo pharmacokinetics, tissue distribution and photodynamic effects of TONS504

Antidepressants Inhibit P2X4 Receptor Function: a Possible Involvement in Neuropathic Pain Relief

BACKGROUND: Neuropathic pain is characterized by pain hypersensitivity to innocuous stimuli (tactile allodynia) that is nearly always resistant to known treatments such as non-steroidal anti-inflammatory drugs or even opioids. It has been reported that some antidepressants are effective for treating neuropathic pain. However, the underlying molecular mechanisms are not well understood. We have recently demonstrated that blocking P2X(4 )receptors in the spinal cord reverses tactile allodynia after peripheral nerve injury in rats, implying that P2X(4 )receptors are a key molecule in neuropathic pain. We investigated a possible role of antidepressants as inhibitors of P2X(4 )receptors and analysed their analgesic mechanism using an animal model of neuropathic pain. RESULTS: Antidepressants strongly inhibited ATP-mediated Ca(2+ )responses in P2X(4 )receptor-expressing 1321N1 cells, which are known to have no endogenous ATP receptors. Paroxetine exhibited the most powerful inhibition of calcium influx via rat and human P2X(4 )receptors, with IC(50 )values of 2.45 μM and 1.87 μM, respectively. Intrathecal administration of paroxetine produced a striking antiallodynic effect in an animal model of neuropathic pain. Co-administration of WAY100635, ketanserin or ondansetron with paroxetine induced no significant change in the antiallodynic effect of paroxetine. Furthermore, the antiallodynic effect of paroxetine was observed even in rats that had received intrathecal pretreatment with 5,7-dihydroxytryptamine, which dramatically depletes spinal 5-hydroxytryptamine. CONCLUSION: These results suggest that paroxetine acts as a potent analgesic in the spinal cord via a mechanism independent of its inhibitory effect on serotonin transporters. Powerful inhibition on P2X(4 )receptors may underlie the analgesic effect of paroxetine, and it is possible that some antidepressants clinically used in patients with neuropathic pain show antiallodynic effects, at least in part via their inhibitory effects on P2X(4 )receptors

Ex-vivo porcine organs with a circulation pump are effective for teaching hemostatic skills

Surgical residents have insufficient opportunites to learn basic hemostatic skills from clinical experience alone. We designed an ex-vivo training system using porcine organs and a circulation pump to teach hemostatic skills. Residents were surveyed before and after the training and showed significant improvement in their self-confidence (1.83 ± 1.05 vs 3.33 ± 0.87, P < 0.01) on a 5 point Likert scale. This training may be effective to educate residents in basic hemostatic skills

A New Evaluation Method of Contact Area at Interface Between Pulsed Surface Discharge and Water

The authors propose a new method for evaluating the contact area of a surface discharge on water by analyzing the resistance of water solution. This method supplements optical observations of light emissions and the Schlieren method. The contact area was modeled as a disk electrode, and the theoretical resistance of water was calculated under the assumption of a mutual similarity between the current and electrostatic fields. A simulated electrostatic field was calculated using a common charge-simulation method. The experimental values of the resistance of water were obtained by dividing the measured voltage drop at water by the measured current. The contact area evaluation was performed by comparing the experimental and theoretical resistance values. The contact area increases with increasing the applied voltage and is practically independent of water depth

Streamer Branching and Spectroscopic Characteristics of Surface Discharge on Water Under Different Pulsed Voltages

Complexity of branching pattern and OH production of water surface discharges was investigated by comparing nanosecond water surface discharge (NWSD) and microsecond water surface discharges (MWSDs) that were defined as NWSD and MWSD, respectively. Experimental and analyzed results between NWSD and MWSD under comparable maximum discharge length l d are summarized as follows: 1) NWSD showed the greatest complexity of branching pattern by fractal analysis; 2) electron density of NWSD was approximately two times greater than MWSD and both orders were 10 -17 cm -3 ; 3) emission intensity of OH (A-X) from MWSD was greater than NWSD; 4) rotational temperature of NWSD was almost constant around 1000 K irrespective of l d and rotational temperature of MWSD increased with increasing l d ranging from 2000 to 4000 K. It was found that the complexity of discharge pattern on water may be affected by the field intensity at water/air boundary. OH production was presumed to be caused by thermal dissociation in this experimental condition

Intracellular Amyloid β Oligomers Impair Organelle Transport and Induce Dendritic Spine Loss in Primary Neurons

Introduction Synaptic dysfunction and intracellular transport defects are early events in Alzheimer’s disease (AD). Extracellular amyloid β (Aβ) oligomers cause spine alterations and impede the transport of proteins and organelles such as brain-derived neurotrophic factor (BDNF) and mitochondria that are required for synaptic function. Meanwhile, intraneuronal accumulation of Aβ precedes its extracellular deposition and is also associated with synaptic dysfunction in AD. However, the links between intracellular Aβ, spine alteration, and mechanisms that support synaptic maintenance such as organelle trafficking are poorly understood. Results We compared the effects of wild-type and Osaka (E693Δ)-mutant amyloid precursor proteins: the former secretes Aβ into extracellular space and the latter accumulates Aβ oligomers within cells. First we investigated the effects of intracellular Aβ oligomers on dendritic spines in primary neurons and their tau-dependency using tau knockout neurons. We found that intracellular Aβ oligomers caused a reduction in mushroom, or mature spines, independently of tau. We also found that intracellular Aβ oligomers significantly impaired the intracellular transport of BDNF, mitochondria, and recycling endosomes: cargoes essential for synaptic maintenance. A reduction in BDNF transport by intracellular Aβ oligomers was also observed in tau knockout neurons. Conclusions Our findings indicate that intracellular Aβ oligomers likely contribute to early synaptic pathology in AD and argue against the consensus that Aβ-induced spine loss and transport defects require tau

Extracellular vesicles synchronize cellular phenotypes of differentiating cells

細胞外小胞が細胞の分化を同調させる現象の発見. 京都大学プレスリリース. 2021-10-01.Cells act in unison when next to each other. 京都大学プレスリリース. 2021-10-01.During embryonic development, cells differentiate in a coordinated manner, aligning their fate decisions and differentiation stages with those of surrounding cells. However, little is known about the mechanisms that regulate this synchrony. Here we show that cells in close proximity synchronize their differentiation stages and cellular phenotypes with each other via extracellular vesicle (EV)-mediated cellular communication. We previously established a mouse embryonic stem cell (ESC) line harbouring an inducible constitutively active protein kinase A (CA-PKA) gene and found that the ESCs rapidly differentiated into mesoderm after PKA activation. In the present study, we performed a co-culture of Control-ESCs and PKA-ESCs, finding that both ESC types rapidly differentiated in synchrony even when PKA was activated only in PKA-ESCs, a phenomenon we named ‘Phenotypic Synchrony of Cells (PSyC)’. We further demonstrated PSyC was mediated by EVs containing miR-132. PKA-ESC-derived EVs and miR-132-containing artificial nano-vesicles similarly enhanced mesoderm and cardiomyocyte differentiation in ESCs and ex vivo embryos, respectively. PSyC is a new form of cell-cell communication mediated by the EV regulation of neighbouring cells and could be broadly involved in tissue development and homeostasis