Increased augmentation of central blood pressure is associated with increases in carotid intima–media thickness in type 2 diabetic patients

Aims/hypothesis Type 2 diabetes is associated with a two- to seven-fold increase in cardiovascular morbidity and mortality. The aim of this study was to determine the relationships between intima–media thickness (IMT), an established marker of atherosclerosis, large artery function and other determinants of cardiovascular risk in type 2 diabetic patients.Methods We studied 228 type 2 diabetic patients (75 women, aged 62±2 years [mean±SEM]). Carotid IMT was bilaterally measured using ultrasound technology. Applanation tonometry and pulse wave analysis were used to measure aortic systolic and diastolic blood pressures, central pressure augmentation (AG) and the augmentation index (AIx), a measure of systemic arterial stiffness. Conventional cardiovascular risk factors (lipids, HbA₁c, smoking and diabetes duration) were also assessed.Results Women had higher AG and AIx (p<0.0001), despite comparable systolic BP and heart rate in women and men. In women, AG (r=0.39, p<0.001), age (r=0.32, p<0.01), brachial systolic BP (r=0.34, p<0.01) and aortic systolic BP (r=0.34, p<0.01) correlated with IMT. In men, age (r=0.41, p<0.001), diabetes duration (r=0.25, p<0.01), AG (r=0.22, p<0.01), aortic systolic BP (r=0.21, p<0.01), brachial systolic BP (r=0.21, p<0.01) and body weight (r=0.16, p<0.05) correlated with IMT. In multiple linear regression analyses, AG and aortic systolic BP, but not brachial systolic BP, were age-independent determinants of IMT in men and women. In all patients, increased AG (adjusted for sex, age and heart rate) correlated with longer duration of diabetes, urinary albumin excretion and IMT.Conclusions/interpretation Measures of central systolic pressure correlate with carotid IMT, independently of age and other risk markers.     

5-单硝酸异山梨醇酯改善高血压患者血压以及血管弹性的临床观察

目的 观察5-单硝酸异山梨醇酯(IS-5-MN)对脉压≥60mmHk高血压患者动脉弹性功能、反射波及血压的影响。方法 选取符合人选条件的30例原发性高血压患者，分两组进行单盲、安慰剂对照研究，每组15人分别给予IS-5-MN(30mg／d)或安慰剂，疗程四周。标准袖带水银血压计测量肱动脉血压，自动脉搏波速度测定仪测定颈动脉-股动脉脉搏波传导速度(CF-PWV)，DO-2020动脉功能测定仪获得大动脉和小动脉弹性指数(C1和C2)，桡动脉压力波形分析获得中心动脉压、外周反射波增压及增强指数。结果 校正安慰剂效应后，(1)患者CF-PWV明显减慢，C1显著提高，C2无明显改变。(2)反射波增压和增强指数明显下降。(3)外周和中心动脉收缩压和脉压显著降低。结论 5-单硝酸异山梨醇酯明显改善脉压≥60mmHg高血压患者的大动脉弹性，减弱外周波反射，降低了收缩压和脉压。     

Charge of a quasiparticle in a superconductor

Nonlinear charge transport in superconductor–insulator–superconductor (SIS) Josephson junctions has a unique signature in the shuttled charge quantum between the two superconductors. In the zero-bias limit Cooper pairs, each with twice the electron charge, carry the Josephson current. An applied bias V_SD leads to multiple Andreev reflections (MAR), which in the limit of weak tunneling probability should lead to integer multiples of the electron charge ne traversing the junction, with n integer larger than 2Δ/eV_SD and Δ the superconducting order parameter. Exceptionally, just above the gap eV_SD ≥ 2Δ, with Andreev reflections suppressed, one would expect the current to be carried by partitioned quasiparticles, each with energy-dependent charge, being a superposition of an electron and a hole. Using shot-noise measurements in an SIS junction induced in an InAs nanowire (with noise proportional to the partitioned charge), we first observed quantization of the partitioned charge q = e*/e = n, with n = 1–4, thus reaffirming the validity of our charge interpretation. Concentrating next on the bias region eV_SD ～ 2Δ, we found a reproducible and clear dip in the extracted charge to q? ～ 0.6, which, after excluding other possibilities, we attribute to the partitioned quasiparticle charge. Such dip is supported by numerical simulations of our SIS structure.Excitations in superconductors (Bogoliubov quasiparticles) can be described according to the Bardeen–Cooper–Schrieffer (BCS) theory (1) as an energy-dependent superposition of an electron with amplitude u(ε), and a hole with amplitude v(ε), where the energy ε is measured relative to the Fermi energy (2). Evidently, the expectation value of the charge operator (applied to the quasiparticle wave function), which we address as the quasiparticle charge e* = q(ε)e, is smaller than the charge of an electron, q(ε) = |u(ε)|² ? |ν(ε)|² (3). Solving the Bogoliubov–de Gennes equations, one finds that |u(ε)|2=1/2[1+(ε2−Δ2/ε)] and |v(ε)|2=1/2[1−(ε2−Δ2/ε)], with the expected charge evolving with energy according to q(ε)=ε2−Δ2/ε––vanishing altogether at the superconductor gap edges (3). Note, however, that the quasiparticle wave function is not an eigenfunction of the charge operator (3, 4). Properties of quasiparticles, such as the excitation spectra (5), lifetime (6–10), trapping (11), and capturing by Andreev bound states (12, 13), had already been studied extensively; however, studies of their charge are lagging. In the following we present sensitive shot-noise measurements in a Josephson junction, resulting in a clear observation of the quasiparticle charge being smaller than e, q(eV_SD∼2Δ) < 1, and evolving with energy, as expected from the BCS theory.To observe the BCS quasiparticles in transport we study a superconductor–insulator–superconductor (SIS) Josephson junction in the nonlinear regime. The overlap between the wave functions of the quasiparticles in the source and in the drain is expected to result in a tunneling current of their effective charge. This is in contrast with systems which are incoherent (14, 15) or with an isolated superconducting island, where charge conservation leads to traversal of multiples of e – Coulomb charge (16). As current transport in the nonlinear regime results from “multiple Andreev reflections” (MAR), it is prudent to make our measurements credible by first measuring the charge in this familiar regime.In short, the MAR process, described schematically in Fig. 1, carries a signature of the shuttled charge between the two superconductors (SCs), being a consequence of n traversals through the junction (as electron-like and hole-like quasiparticles), with n an integer larger than 2Δ/eV_SD. A low transmission probability t (via tunneling through a barrier) in the bias range 2Δ/n < eV_SD < 2Δ/(n ? 1) assures dominance of the lowest order MAR process (higher orders are suppressed as tⁿ), with the charge evolving in nearly integer multiples of the electron charge. Although there is already a substantial body of theoretical (3, 17–23) and experimental (24–29) studies of the MAR process, charge determination without adjustable parameters is still missing. An important work by Cron et al. (27) indeed showed a staircase-like behavior of the charge using “metallic break junctions;” however, limited sensitivity and the presence of numerous conductance channels some of which with relatively high transmission probabilities did not allow exact charge quantization. Our shot-noise measurements, performed on a quasi-1D Josephson junction (single-mode nanowire) allowed clear observation of charge quantization without adjustable parameters. To count a few advantages: (i) the transmission of the SIS junction could be accurately controlled using a back-gate; (ii) this, along with our high sensitivity in noise measurements, enabled us to pinch the junction strongly (thus suppressing higher MAR orders); and (iii) with the Fermi level located near the 1D channel van Hove singularity, a rather monoenergetic distribution could be injected (SI Appendix, section S7).Open in a separate windowFig. 1.MAR. Illustrations of the leading processes contributing to the current as function of bias. In general, for 2Δ/(n ? 1) > eV_SD > 2Δ/n the leading charge contribution to the current is ne. An electron-like quasiparticle is denoted by a full circle, whereas a hole-like quasiparticle is denoted by an empty circle. (A) When the bias is larger than the energy gap, eV_SD > 2Δ, the leading process is a single-path tunneling of single quasiparticles from the full states (Left) to the empty states (Right). This current is proportional to the transmission coefficient t. Higher-order MAR process (dashed box), being responsible for tunneling of Cooper pairs, is suppressed as t². (B) For 2Δ > eV_SD > Δ, the main charge contributing to the current is 2e with probability t². (C) For Δ > eV_SD > 2Δ/3, the main charge contributing to the current is 3e with probability t³.     

军队医院野战应急保障力量建设思考

本文对军队医院卫勤保障分队普遍存在的问题进行分析,对加强军队医院野战应急保障分队力量建设进行思考,并提出建议,对提高军队医院野战应急保障能力具有借鉴和指导作用。     

基于PDCA循环的医院信息系统建设

我国医院信息建设的步伐在不断加快,信息建设的内容也不断深入。从统计数据也表明医院在信息建设的投入也逐年增多。无论是开展信息化较早的医院还是刚起步的单位,都应该按照PDCA（Plan-Do-Check-Action）原则定期审视所建项目。通过反思检验和评估信息建设的效果是否达到当初的设计目的,使用者的需求是否得到有效的响应,只有这样才能更好发挥信息系统的成效。     

Understanding the essential elements of work-based learning and its relevance to everyday clinical practice

williams c. (2010) Journal of Nursing Management  18, 624–632
Understanding the essential elements of work-based learning and its relevance to everyday clinical practice Aim To critically review the work-based learning literature and explore the implications of the findings for the development of work-based learning programmes. Background With NHS budgets under increasing pressure, and challenges to the impact of classroom-based learning on patient outcomes, work-based learning is likely to come under increased scrutiny as a potential solution. Evidence from higher education institutions suggests that work-based learning can improve practice, but in many cases it is perceived as little more than on-the-job training to perform tasks. Evaluation The CINAHL database was searched using the keywords work-based learning, work-place learning and practice-based learning. Those articles that had a focus on post-registration nursing were selected and critically reviewed. Key issues Using the review of the literature, three key issues were explored. Work-based learning has the potential to change practice. Learning how to learn and critical reflection are key features. For effective work-based learning nurses need to take control of their own learning, receive support to critically reflect on their practice and be empowered to make changes to that practice. Conclusions A critical review of the literature has identified essential considerations for the implementation of work-based learning. A change in culture from classroom to work-based learning requires careful planning and consideration of learning cultures. Implications for nursing management To enable effective work-based learning, nurse managers need to develop a learning culture in their workplace. They should ensure that skilled facilitation is provided to support staff with critical reflection and effecting changes in practice. Contribution to New Knowledge This paper has identified three key issues that need to be considered in the development of work-based learning programmes.     

Microtubule plus-end tracking by CLIP-170 requires EB1

Microtubules are polarized polymers that exhibit dynamic instability, with alternating phases of elongation and shortening, particularly at the more dynamic plus-end. Microtubule plus-end tracking proteins (+TIPs) localize to and track with growing microtubule plus-ends in the cell. +TIPs regulate microtubule dynamics and mediate interactions with other cellular components. The molecular mechanisms responsible for the +TIP tracking activity are not well understood, however. We reconstituted the +TIP tracking of mammalian proteins EB1 and CLIP-170 in vitro at single-molecule resolution using time-lapse total internal reflection fluorescence microscopy. We found that EB1 is capable of dynamically tracking growing microtubule plus-ends. Our single-molecule studies demonstrate that EB1 exchanges rapidly at microtubule plus-ends with a dwell time of <1 s, indicating that single EB1 molecules go through multiple rounds of binding and dissociation during microtubule polymerization. CLIP-170 exhibits lattice diffusion and fails to selectively track microtubule ends in the absence of EB1; the addition of EB1 is both necessary and sufficient to mediate plus-end tracking by CLIP-170. Single-molecule analysis of the CLIP-170–EB1 complex also indicates a short dwell time at growing plus-ends, an observation inconsistent with the copolymerization of this complex with tubulin for plus-end-specific localization. GTP hydrolysis is required for +TIP tracking, because end-specificity is lost when tubulin is polymerized in the presence of guanosine 5′-[α,β-methylene]triphosphate (GMPCPP). Together, our data provide insight into the mechanisms driving plus-end tracking by mammalian +TIPs and suggest that EB1 specifically recognizes the distinct lattice structure at the growing microtubule end.     

Post‐exercise aortic hemodynamic responses to low‐intensity resistance exercise with and without vascular occlusion

High‐intensity resistance exercise may acutely increase arterial stiffness. Vascular occlusion (VO) acutely decreases arterial stiffness. The purpose of this study was to evaluate acute aortic hemodynamic responses to low‐intensity resistance exercise (LIRE) with slow eccentric movement with and without VO. Twenty‐three young healthy subjects (12 women and 11 men) were randomized into three trials: seated control (CON), LIRE (six sets at 40% one repetition maximum), and LIRE with VO. Vascular measurements were assessed before, immediately (post1), and 30 min after (post30) each trial. There were significant (P<0.05) time effects and trial‐by‐time interactions such that the changes were greater after the LIRE trials compared with CON. Aortic blood pressure [systolic (～10 mmHg) and diastolic (～5 mmHg)], heart rate (～23 b.p.m.), and the first (～10 mmHg) and second systolic peak (～9 mmHg) increased, whereas time to reflection decreased (～15 ms) at post1. All measurements returned to baseline at post30, except aortic augmentation index (AIx), which decreased ～5% after the LIRE trials compared with CON. Increases in cardiovascular variables immediately after the LIRE trials were mild and short lasting. Our results indicate that LIRE acutely decreases AIx 30 min after exercise cessation. The use of moderate intermittent VO during LIRE does not produce additional post‐exercise vascular effects.     

Cross-talk between macro- and microcirculation

Physiologically, macro- and microcirculation differ markedly as macrocirculation deals with pulsatile pressure and flow and microcirculation with steady pressure and flow. Various such haemodynamic aspects correspond to a large heterogeneity in the structure and function of the vascular tree. In the past, diseases such as hypertension and diabetes mellitus were classified on the basis of the structure and function of small and large arteries. The purpose of this paper is to review the cross-talk between the micro- and macrocirculation. We shall discuss this cross-talk from the perspective of the development, physiology and pathology of the entire arterial tree.