Breath water-based doubly labelled water method for the noninvasive determination of CO2 production and energy expenditure in mice

ABSTRACT

We explored a novel doubly labelled water (DLW) method based on breath water (BW-DLW) in mice to determine whole body CO₂ production and energy expenditure noninvasively. The BW-DLW method was compared to the DLW based on blood plasma. Mice (n?=?11, 43.5?±?4.6?g body mass (BM)) were administered orally a single bolus of doubly labelled water (1.2?g H₂¹⁸O kg BM^?1 and 0.4?g ²H₂O kg BM^?1, 99 atom% (AP) ¹⁸O or ²H). To sample breath water, the mice were placed into a respiration vessel. The exhaled water vapour was condensed in a cold-trap. The isotope enrichments of breath water were compared with plasma samples. The ²H/¹H and ¹⁸O/¹⁶O isotope ratios were measured by means of isotope ratio mass spectrometry. The CO₂ production (RCO₂) was calculated from the ²H and ¹⁸O enrichments in breath water and plasma over 5 days. The isotope enrichments of breath water vs. plasma were correlated (R²?=?0.89 for ²H and 0.95 for ¹⁸O) linearly. The RCO₂ determined based on breath water and plasma was not different (113.2?±?12.7 vs. 111.4?±?11.0?mmol?d^–1), respectively. In conclusion, the novel BW-DLW method is appropriate to obtain reliable estimates of RCO₂ avoiding blood sampling.     

The universe—present,past and future

A review of The Superpower Space Race: An Explosive Rivalry through the Solar System. By Robert Reeves. (Plenum, 1994) [Pp. xiv + 437.] US$ 28·95 (hbk). ISBN 0 306 447681. Scope: popular review. Level: general reader.     

中国医学物理学的过去、现在与未来

医学物理（medical physics，MP）是把物理学的原理和方法应用于人类疾病的预防、诊断、治疗和保健的一门交叉学科，是物理学与医学实践相结合的一门独立的分支学科．它是研究人类疾病诊、治过程中的物理现象，并用物理方法表达这种现象．医学物理包括放射肿瘤物理（rsdiation oncdogy physics，ROP）、医学影像物理（medical imaong physics，MIP）、核医学物理（nuclear medicine physics，NMP），其他非电离辐射如核磁、超声、微波、射频、激光等物理因子在医学中的应用，和保健物理（heath physics，HP）等分支内容．医学物理学和生物医学工程学（biomedical engineefing，BME）是一对栾生的兄弟学科，分别从物理学的角度（前者）和工程学的角度（后者）研究人类疾病诊断、治疗及健康保健过程中的生命现象和采取相应的物理措施和工程手段。医学物理学与物理医学（physical medicine，PM）是完全两个不同的概念，前者是物理学的分支，后者是医学的分支．自上世纪60年代以来，中国医学物理学有了很大的进展，推动了中国现代放射肿瘤学、核医学和医学影像学的发展；成立了自己的学术组织，并成为国际医学物理组织（IOMP）的成员国组织．随着中国逐步奔入小康社会，为适应人民大众对健康的需求和现代化医院发展的需要，中国医学物理应该加快发展．     

中国医学物理学的过去、现在与未来

医学物理(medicalphysics,MP)是把物理学的原理和方法应用于人类疾病的预防、诊断、治疗和保健的一门交叉学科,是物理学与医学实践相结合的一门独立的分支学科.它是研究人类疾病诊、治过程中的物理现象,并用物理方法表达这种现象.医学物理包括放射肿瘤物理(radiation oncology physics, ROP)、医学影像物理(medical imaging physics, MIP)、核医学物理(nuclear medicine physics, NMP),其他非电离辐射如核磁、超声、微波、射频、激光等物理因子在医学中的应用,和保健物理(health physics, HP)等分支内容.医学物理学和生物医学工程学(biomedical engineering,BME)是一对栾生的兄弟学科,分别从物理学的角度(前者)和工程学的角度(后者)研究人类疾病诊断、治疗及健康保健过程中的生命现象和采取相应的物理措施和工程手段.医学物理学与物理医学(physical medicine, PM)是完全两个不同的概念,前者是物理学的分支,后者是医学的分支.自上世纪60年代以来,中国医学物理学有了很大的进展,推动了中国现代放射肿瘤学、核医学和医学影像学的发展; 成立了自己的学术组织,并成为国际医学物理组织(IOMP)的成员国组织.随着中国逐步奔入小康社会,为适应人民大众对健康的需求和现代化医院发展的需要,中国医学物理应该加快发展.     

锂离子电池过往与未来

2019年诺贝尔化学奖授予从事锂离子电池研究的三位杰出科学家,让锂离子电池这项技术成为社会大众视野焦点,也表明了锂离子电池在推动人类社会科学技术进步中所做出的贡献得到了科学界一致认可。文章结合三位获奖者的工作对锂离子电池的发明及其过往历史做一简单梳理和介绍,并在此基础上谈谈锂离子电池技术未来面临的机遇和存在的挑战。     

超导电力技术新进展及其未来发展的思考

近年来高温超导材料研究取得很大进展,它在电力领域的应用研究已受到广泛关注,一些示范样机,诸如高温超导输电电缆、变压器、故障电流限制器、电机和储能装置已经研制成功并投入示范性试验.超导技术是21世纪具有战略经济意义的高新技术,文章将介绍高温超导电力应用研究的新进展及其未来发展的思考。     

The determination of the past and the future of a physical system in quantum mechanics

The determination of the past and the future of a physical system are complementary aims of measurements. An optimal determination of the past of a system can be achieved by an informationally complete set of physical quantities. Such a set is always strongly noncommutative. An optimal determination of the future of a physical system can be obtained by a Boolean complete set of quantities. The two aims can be reconciled to a reasonable degree with using unsharp measurements.This work was partly supported by the Bundesministerium für Forschung und Technologie, Bonn, the Research Institute for Theoretical Physics, Helsinki, and the University of Turku Foundation, Turku.     

超导电力技术新进展及其未来发展的思考

近年来高温超导材料研究取得很大进展,它在电力领域的应用研究已受到广泛关注,一些示范样机,诸如高温超导输电电缆、变压器、故障电流限制器、电机和储能装置已经研制成功并投入示范性试验.超导技术是21世纪具有战略经济意义的高新技术,文章将介绍高温超导电力应用研究的新进展及其未来发展的思考.     

脑磁图仪的前世今生与未来

脑磁图仪通过记录大脑神经活动在头皮外产生的磁场来进行脑活动的成像,它具备超高的时间分辨率和较高的空间分辨率,是一种重要的无创脑功能成像技术。文章介绍了脑磁信号的神经生理起源、生物物理特征及其与脑电信号的联系和区别,回顾了当前基于超导量子干涉仪的脑磁图设备与相关技术,并针对制约当前超导脑磁图发展的技术瓶颈,介绍了基于原子磁强计的新型脑磁探测技术及国内相关研究的最新进展,指出了脑磁图在脑科学研究及临床应用中不可或缺的地位和其硬件技术未来发展的方向。     

Entanglement between the future and the past in the quantum vacuum

We note that massless fields within the future and past light cone may be quantized as independent systems. The vacuum is shown to be a nonseparable state of these systems, exactly mirroring the known entanglement between the spacelike separated Rindler wedges. This leads to a notion of timelike entanglement. We describe an inertial detector which exhibits a thermal response to the vacuum when switched on at t=0, due to this property. The feasibility of detecting this effect is discussed, with natural experimental parameters appearing at the scale of 100?GHz.     

煤的清洁利用技术的现状与发展

文章针对中国一次能源以煤为主的特点,深入分析了几种主要的煤的洁净利用技术的现状及存在的主要问题和发展趋势,其中包括大容量、高参数的超(超)临界燃煤发电技术、燃煤烟气净化技术、循环流化床燃烧技术(CFBC)、整体煤气化联合循环技术(IGCC)和煤的洗选技术.在此基础上,给出了中国煤的清洁利用方式的建议:近期仍以超(超)临界燃煤发电机组+燃煤烟气净化技术和循环流化床燃烧技术为主;整体燃气化联合循环技术、富氧燃烧技术(特别是加压富氧燃烧技术)以及二氧化碳的捕集和封存技术(CCS),具有广阔应用前景,值得长期大力发展.     

煤的清洁利用技术的现状与发展

文章针对中国一次能源以煤为主的特点,深入分析了几种主要的煤的洁净利用技术的现状及存在的主要问题和发展趋势,其中包括大容量、高参数的超（超）临界燃煤发电技术、燃煤烟气净化技术、循环流化床燃烧技术(CFBC)、整体煤气化联合循环技术(IGCC)和煤的洗选技术.在此基础上,给出了中国煤的清洁利用方式的建议：近期仍以超（超）临界燃煤发电机组+燃煤烟气净化技术和循环流化床燃烧技术为主;整体燃气化联合循环技术、富氧燃烧技术（特别是加压富氧燃烧技术）以及二氧化碳的捕集和封存技术(CCS),具有广阔应用前景,值得长期大力发展.     

美国激光制导武器的发展现状与趋势

文章重点介绍了激光制导的原理和方式,同时用几种典型的激光制导武器说明了美国在此方面的发展,对激光武器的优缺点及其发展趋势也作出了深刻的分析.     

美国激光制导武器的发展现状与趋势

文章重点介绍了激光制导的原理和方式,同时用几种典型的激光制导武器说明了美国在此方面的发展,对激光武器的优缺点及其发展趋势也作出了深刻的分析.     

Hyperfine interactions: the past, the present and the future

Five major hyperfine interaction techniques, detected by nuclear radiation, originated in the short time span between 1950 and 1965. The coincidence with the demographic expansion, especially in Europe, of university education led to the creation of many new research laboratories applying these promising techniques in solid state physics, chemistry and biology. Since the turn of century many of the early pioneers are going into retirement, leading to a decline in activities in Europe, compensated in some degree by an increase in activities outside Europe. The organisation of the 2007 HI/NQI-conference was impeccable and took place in a superb setting. Thanks to all those involved in its organization.     

CP violation: the past, the present and the future

We have just entered a period during which we expect considerable progress toward understanding CP violation. Here we review what we have learnt so far, and what is to be expected in the near future. To do this we cover the foundation of CP violation at a level which can be understood by physicists who are not working in this field.     

The proton form factor measurements at Jefferson Lab, past and future

Use of the double-polarization technique to obtain the elastic nucleon form factors has resulted in a dramatic improvement of the quality of two of the four nucleon electromagnetic form factors, G _Ep and G _En . It has also changed our understanding of the proton structure, having resulted in a distinctly different Q ²-dependence for both G _Ep and G _Mp , contradicting the prevailing wisdom of the 1990’s based on cross section measurements, namely that G _Ep and G _Mp obey a “scaling” relation μG _Ep ～ G _Mp . A related consequence of the faster decrease of G _Ep revealed by the Jefferson Lab (JLab) polarization results was the disappearance of the early scaling F ₂/F ₁ ～ 1/Q ² predicted by perturbative QCD. In three experiments, GEp(1), GEp(2) and GEp(3), in Halls A and C at JLab, the ratio of the proton’s electromagnetic elastic form factors, G _Ep /G _Mp , was measured up to four momentum transfer Q ² of 8.5 GeV² with high precision, using the recoil polarization technique. The initial discovery that the proton form factor ratio measured in these three experiments decreases approximately linearly with four-momentum transfer, Q ², for values above ～ 1 GeV², was modified by the GEp(3) results, which suggests a slowing down of this decrease. There is an approved experiment, GEp(5), to continue these measurements to 15 GeV². A dedicated experimental setup, the super bigbite spectrometer (SBS), will be built for this purpose. It will be equipped with a new focal plane polarimeter to measure the polarization of the recoil protons. In this presentation, I will review the status of the proton elastic electromagnetic form factors, mention succinctly a number of theoretical approaches to describe results and show some features required for the future GEp(5) experiment.     

The Hartree-Fock method with orthogonality restrictions for doubly excited and ionized states

It is shown that the doubly excited and ionized states with vacancies in the K electronic shells can be considered within the framework of the same scheme on the basis of the asymptotic projection method proposed earlier. In contrast to the conventional methods, the electron detachment effect is achieved by imposing the requirement that the orbitals of the excited (hole) state be orthogonal to the orbitals of removed electrons. The solution of equations that determine the orbitals is implemented in terms of the conventional spin-unrestricted Hartree-Fock method with additional conditions that ensure the spin purity and provide a unique choice of the zero-order approximation in constructing the many-particle perturbation theory for taking into account the correlation effects. The performance of the method is demonstrated by calculating the excitation energies and ionization potentials corresponding to the removal of electrons from the inner K-shell.     

Genetic variations in medical research in the past,at present and in the future

As we look so different, our genomic sequences vary enormously. The differences in our genome, genetic variations, have played very significant roles in medical research and have contributed to improvement of medical managements in the last 2–3 decades. Genetic variations include germline variations, somatic mutations, and diversities in receptor genes of rearranged immune cells, T cells and B cells. Germline variants are in some cases causative of genetic diseases, are associated with the risk of various diseases, and also affect drug efficacies or adverse events. Some somatic mutations are causative of tumor development. Recent DNA sequencing technologies allow us to perform single-cell analysis or detailed repertoire analysis of B and T cells. It is critically important to investigate temporal changes in immune environment in various anatomical regions in the next one to two decades. In this review article, we would like to introduce the roles of genetic variations in medical fields in the past, at present and in the future.