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Biomolecules Oct 2022Small-angle neutron scattering (SANS) is a powerful tool for studying biological membranes and model lipid bilayer membranes. The length scales probed by SANS, being... (Review)
Review
Small-angle neutron scattering (SANS) is a powerful tool for studying biological membranes and model lipid bilayer membranes. The length scales probed by SANS, being from 1 nm to over 100 nm, are well-matched to the relevant length scales of the bilayer, particularly when it is in the form of a vesicle. However, it is the ability of SANS to differentiate between isotopes of hydrogen as well as the availability of deuterium labeled lipids that truly enable SANS to reveal details of membranes that are not accessible with the use of other techniques, such as small-angle X-ray scattering. In this work, an overview of the use of SANS for studying unilamellar lipid bilayer vesicles is presented. The technique is briefly presented, and the power of selective deuteration and contrast variation methods is discussed. Approaches to modeling SANS data from unilamellar lipid bilayer vesicles are presented. Finally, recent examples are discussed. While the emphasis is on studies of unilamellar vesicles, examples of the use of SANS to study intact cells are also presented.
Topics: Scattering, Small Angle; Lipid Bilayers; Neutron Diffraction; Neutrons; Unilamellar Liposomes
PubMed: 36358941
DOI: 10.3390/biom12111591 -
Photosynthesis Research Dec 2021The photosynthetic performance of crop plants under a variety of environmental factors and stress conditions, at the fundamental level, depends largely on the...
The photosynthetic performance of crop plants under a variety of environmental factors and stress conditions, at the fundamental level, depends largely on the organization and structural flexibility of thylakoid membranes. These highly organized membranes accommodate virtually all protein complexes and additional compounds carrying out the light reactions of photosynthesis. Most regulatory mechanisms fine-tuning the photosynthetic functions affect the organization of thylakoid membranes at different levels of the structural complexity. In order to monitor these reorganizations, non-invasive techniques are of special value. On the mesoscopic scale, small-angle neutron scattering (SANS) has been shown to deliver statistically and spatially averaged information on the periodic organization of the thylakoid membranes in vivo and/or, in isolated thylakoids, under physiologically relevant conditions, without fixation or staining. More importantly, SANS investigations have revealed rapid reversible reorganizations on the timescale of several seconds and minutes. In this paper, we give a short introduction into the basics of SANS technique, advantages and limitations, and briefly overview recent advances and potential applications of this technique in the physiology and biotechnology of crop plants. We also discuss future perspectives of neutron crystallography and different neutron scattering techniques, which are anticipated to become more accessible and of more use in photosynthesis research at new facilities with higher fluxes and innovative instrumentation.
Topics: Neutrons; Photosynthesis; Scattering, Small Angle; Thylakoids
PubMed: 32488447
DOI: 10.1007/s11120-020-00763-6 -
Cancer Communications (London, England) Jun 2018Boron neutron capture therapy (BNCT) is a binary radiotherapeutic modality based on the nuclear capture and fission reactions that occur when the stable isotope,... (Review)
Review
Boron neutron capture therapy (BNCT) is a binary radiotherapeutic modality based on the nuclear capture and fission reactions that occur when the stable isotope, boron-10, is irradiated with neutrons to produce high energy alpha particles. This review will focus on tumor-targeting boron delivery agents that are an essential component of this binary system. Two low molecular weight boron-containing drugs currently are being used clinically, boronophenylalanine (BPA) and sodium borocaptate (BSH). Although they are far from being ideal, their therapeutic efficacy has been demonstrated in patients with high grade gliomas, recurrent tumors of the head and neck region, and a much smaller number with cutaneous and extra-cutaneous melanomas. Because of their limitations, great effort has been expended over the past 40 years to develop new boron delivery agents that have more favorable biodistribution and uptake for clinical use. These include boron-containing porphyrins, amino acids, polyamines, nucleosides, peptides, monoclonal antibodies, liposomes, nanoparticles of various types, boron cluster compounds and co-polymers. Currently, however, none of these have reached the stage where there is enough convincing data to warrant clinical biodistribution studies. Therefore, at present the best way to further improve the clinical efficacy of BNCT would be to optimize the dosing paradigms and delivery of BPA and BSH, either alone or in combination, with the hope that future research will identify new and better boron delivery agents for clinical use.
Topics: Boron; Boron Compounds; Boron Neutron Capture Therapy; Humans; Isotopes; Liposomes; Neoplasms; Neutrons; Tissue Distribution
PubMed: 29914561
DOI: 10.1186/s40880-018-0299-7 -
Proceedings of the Japan Academy.... 2024The current understanding of the mechanism of core-collapse supernovae (CCSNe), one of the most energetic events in the universe associated with the death of massive... (Review)
Review
The current understanding of the mechanism of core-collapse supernovae (CCSNe), one of the most energetic events in the universe associated with the death of massive stars and the main formation channel of compact objects such as neutron stars and black holes, is reviewed for broad readers from different disciplines of science who may not be familiar with the object. Therefore, we emphasize the physical aspects than the results of individual model simulations, although large-scale high-fidelity simulations have played the most important roles in the progress we have witnessed in the past few decades. It is now believed that neutrinos are the most important agent in producing the commonest type of CCSNe. The so-called neutrino-heating mechanism will be the focus of this review and its crucial ingredients in micro- and macrophysics and in numerics will be explained one by one. We will also try to elucidate the remaining issues.
Topics: Neutrons; Stars, Celestial
PubMed: 38462501
DOI: 10.2183/pjab.100.015 -
International Journal of Pharmaceutics Nov 2023Hydrotropism is a convenient way to increase the solubility of drugs by up to several orders of magnitude, and even though it has been researched for decades with both...
Hydrotropism is a convenient way to increase the solubility of drugs by up to several orders of magnitude, and even though it has been researched for decades with both experimental and simulation methods, its mechanism is still unknown. Here, we use caffeine/sodium benzoate (CAF-SB) as model system to explore the behaviour of caffeine solubility enhancement in water through NMR spectroscopy and neutron total scattering. H NMR shows strong interaction between caffeine and sodium benzoate in water. Neutron total scattering combined with empirical potential structure refinement, a systematic method to study the solution structure, reveals π-stacking between caffeine and the benzoate anion as well as Coulombic interactions with the sodium cation. The strongest hydrogen bond interaction in the system is between benzoate and water, which help dissolve CAF-SB complex and increase the solubility of CAF in water. Besides, the stronger interaction between CAF and water and the distortion of water structure are further mechanisms of the CAF solubility enhancement. It is likely that the variety of mechanisms for hydrotropism shown in this system can be found for other hydrotropes, and NMR spectroscopy and neutron total scattering can be used as complementary techniques to generate a holistic picture of hydrotropic solutions.
Topics: Sodium Benzoate; Caffeine; Magnetic Resonance Spectroscopy; Benzoates; Water; Neutrons
PubMed: 37858637
DOI: 10.1016/j.ijpharm.2023.123520 -
Igaku Butsuri : Nihon Igaku Butsuri... 2022Exposure of human body to neutrons occurs in radiotherapy using high-energy radiations. This review summarizes knowledges related to biological effects of neutrons,... (Review)
Review
Exposure of human body to neutrons occurs in radiotherapy using high-energy radiations. This review summarizes knowledges related to biological effects of neutrons, including those obtained in recent projects in Japan and Europe. A study of Japanese atomic bomb survivors with recently revised dosimetry indicated very high relative biological effectiveness (RBE) of 25-80 (as point estimates) regarding cancer risk. Animal studies indicate RBE of 2-100 or even higher regarding cancer induction, which seem to have a peak around ~1 MeV. Evidence suggests that these values depend on the age and sex. Reported RBE regarding the effects on the lens of the eye is in a similar range and sometimes very high. Regarding other tissue reactions, reported RBE values range from 2-10. Experiments at the cellular level have reported RBE of 1-5 regarding cell killing, 2-20 regarding induction of mutations (with a peak at ~1 MeV), and ~1 regarding induction of DNA double strand breaks. A simulation study predicted that the RBE of induction of complex DNA breaks peaks at ~1 MeV with a value of ~17. The complex breaks produced are likely to be far less in amount than simple DNA breaks, leading to a subtle increase in the yield of total DNA breaks; however, these complex damages may be very efficient in inducing mutations and cancer. Thus, the combination of the yield of complex DNA damage and its efficacy in inducing cancer is considered to underlie the high RBE of neutrons regarding cancer risk.
Topics: Animals; Neoplasms; Neutrons; Radiometry; Relative Biological Effectiveness; Risk
PubMed: 35768264
DOI: 10.11323/jjmp.42.2_73 -
Journal of Oleo Science Oct 2022Polyethyleneglycol 12 mol / polydimethylsiloxane co-polymer (PEG-12 dimethicone) is a type of polyether modified silicone (PEMS), which can form a lamellar liquid...
Polyethyleneglycol 12 mol / polydimethylsiloxane co-polymer (PEG-12 dimethicone) is a type of polyether modified silicone (PEMS), which can form a lamellar liquid crystalline phase, and is widely used in cosmetics. The structural changes of PEG-12 dimethicone caused by water contents as well as shear flow were evaluated using simultaneous measurements of rheology and small angle neutron scattering (Rheo-SANS) and neutron reflectometry (NR). At high PEG-12 dimethicone concentrations (≥ 36 wt%), a reorientation of plate-like lamellar structures were observed and the neutral orientation was the most favorable. However, lamella-to-vesicle transitions were hardly observed. PEG-12 dimethicone turned out to form a bi-layer on a hydrophilized Si-wafer in a similar manner to that in bulk though the structure had a certain level of roughness.
Topics: Scattering, Small Angle; Silicones; Rheology; Neutrons
PubMed: 36198585
DOI: 10.5650/jos.ess22190 -
Nature Communications Apr 2023Boron neutron capture therapy (BNCT) was clinically approved in 2020 and exhibits remarkable tumour rejection in preclinical and clinical studies. It is binary...
Boron neutron capture therapy (BNCT) was clinically approved in 2020 and exhibits remarkable tumour rejection in preclinical and clinical studies. It is binary radiotherapy that may selectively deposit two deadly high-energy particles (He and Li) within a cancer cell. As a radiotherapy induced by localized nuclear reaction, few studies have reported its abscopal anti-tumour effect, which has limited its further clinical applications. Here, we engineer a neutron-activated boron capsule that synergizes BNCT and controlled immune adjuvants release to provoke a potent anti-tumour immune response. This study demonstrates that boron neutron capture nuclear reaction forms considerable defects in boron capsule that augments the drug release. The following single-cell sequencing unveils the fact and mechanism that BNCT heats anti-tumour immunity. In female mice tumour models, BNCT and the controlled drug release triggered by localized nuclear reaction causes nearly complete regression of both primary and distant tumour grafts.
Topics: Male; Female; Animals; Mice; Boron; Neoplasms; Boron Neutron Capture Therapy; Immunotherapy; Neutrons; Boron Compounds
PubMed: 37019890
DOI: 10.1038/s41467-023-37253-x -
The Journal of Physical Chemistry. B Sep 2021Caffeine is not only a widely consumed active stimulant, but it is also a model molecule commonly used in pharmaceutical sciences. In this work, by performing...
Caffeine is not only a widely consumed active stimulant, but it is also a model molecule commonly used in pharmaceutical sciences. In this work, by performing quartz-crystal microbalance and neutron reflectometry experiments we investigate the interaction of caffeine molecules with a model lipid membrane. We determined that caffeine molecules are not able to spontaneously partition from an aqueous environment, enriched in caffeine, into a bilayer. Caffeine could be however included in solid-supported lipid bilayers if present with lipids during self-assembly. In this case, thanks to surface-sensitive techniques, we determined that caffeine molecules are preferentially located in the hydrophobic region of the membrane. These results are highly relevant for the development of new drug delivery vectors, as well as for a deeper understanding of the membrane permeation role of purine molecules.
Topics: Caffeine; Hydrophobic and Hydrophilic Interactions; Lipid Bilayers; Neutrons; Quartz Crystal Microbalance Techniques
PubMed: 34469176
DOI: 10.1021/acs.jpcb.1c04360 -
The Journal of Physical Chemistry. B Dec 2022The microscopic structure of nitric oxide is investigated using neutron scattering experiments. The measurements are performed at various temperatures between 120 and...
The microscopic structure of nitric oxide is investigated using neutron scattering experiments. The measurements are performed at various temperatures between 120 and 144 K and at pressures between 1.1 and 9 bar. Using the technique of empirical potential structure refinement (EPSR), our results show that the dimer is the main form, around 80%, of nitric oxide in the liquid phase at 120 K, but the degree of dissociation to monomers increases with increasing temperature. The reported degree of dissociation of dimers, and its trend with increasing temperature, is consistent with earlier measurements and studies. It is also shown that nonplanar dimers are not inconsistent with the diffraction data and that the possibility of nitric oxide molecules forming longer oligomers, consisting of bonded nitrogen atoms along the backbone, cannot be ruled out in the liquid. A molecular dynamics simulation is used to compare the present EPSR simulations with an earlier proposed intermolecular potential for the liquid.
Topics: Nitric Oxide; Molecular Dynamics Simulation; Neutrons; Nitrogen; Polymers
PubMed: 36399601
DOI: 10.1021/acs.jpcb.2c05384