Background —Myocardial perfusion reserve can be noninvasively assessed with cardiovascular MR. In this study, the diagnostic accuracy of this technique for the detection of significant coronary artery stenosis was evaluated. Methods and Results —In 15 patients with single-vessel coronary artery disease and 5 patients without significant coronary artery disease, the signal intensity–time curves of the first pass of a gadolinium-DTPA bolus injected through a central vein catheter were evaluated before and after dipyridamole infusion to validate the technique. A linear fit was used to determine the upslope, and a cutoff value for the differentiation between the myocardium supplied by stenotic and nonstenotic coronary arteries was defined. The diagnostic accuracy was then examined prospectively in 34 patients with coronary artery disease and was compared with coronary angiography. A significant difference in myocardial perfusion reserve between ischemic and normal myocardial segments (1.08±0.23 and 2.33±0.41; P <0.001) was found that resulted in a cutoff value of 1.5 (mean minus 2 SD of normal segments). In the prospective analysis, sensitivity, specificity, and diagnostic accuracy for the detection of coronary artery stenosis (≥75%) were 90%, 83%, and 87%, respectively. Interobserver and intraobserver variabilities for the linear fit were low ( r =0.96 and 0.99). Conclusions —MR first-pass perfusion measurements yielded a high diagnostic accuracy for the detection of coronary artery disease. Myocardial perfusion reserve can be easily and reproducibly determined by a linear fit of the upslope of the signal intensity–time curves.

Zinc hydroxide nitrate, Zns(OH)s(NO3)2.2HzO, is monoclinic with a= 19.480 (5), b=6.238 (1), c= 5.517 (1) A, fl= 93-28 o (2), space group C2/m, two formula units per cell. The structure has been determined from Patterson and Fourier syntheses. The refinement was done by the method of least squares. The final R value for 491 observed Weissenberg reflexions was 6"4%. The structure is characterized by zinc atoms occuring in both octahedral and tetrahedral coordination in the ratio 3:2. The octahedral zinc atoms, surrounded by six OH groups, belong to a CdI~-type sheet with ¼ of the metal atoms missing. The tetrahedrally coordinated zinc atoms are located above and below the empty octahedra. The tetrahedra are formed by three OH groups and one water molecule. The nitrate group is not directly involved in the coordination of the metal atoms. The average tetrahedral Zn-O distance of 1.95 A is significantly shorter than the mean octahedral Zn-O distance of 2.13 A. Zinc hydroxide nitrate is obtained as a microcrystalline powder by reaction of ZnO or Zn(OH)z with aqueous Zn(NO3)2 solutions (Feitknecht, 1933). Single crystals can be grown by precipitation from homogeneous solution of zinc nitrate with urea at 60 °C (both concentrations e.g. 1 molar). ExperimentalThe chemical formula Zns(OH)s(NO3)z. 2H20 was established by chemical and thermogravimetric analysis. X-ray powder diagrams for the determination of ac-curate unit-cell dimensions were taken with a focusing camera of the Guinier-de Wolff type with Fe Ke and Cu Kcc radiation. High purity potassium chloride was used as an internal standard. Multiple-film integrated Weissenberg photographs of the layers hOl, hll to h41 were taken on a Nonius camera with Cu Kcc radiation (Ni filter). Intensities of the layers hkO and Okl were collected by the multiple exposure technique with Zrfiltered Mo radiation on a Buerger precession camera. The blackening of the films was measured with a Joyce-Loebl mark III CS double-beam microdensitometer. The data from the layers hk0 and Okl were used to

No abstract

No abstract

The structures of single crystals of [bipyH]+ [Fen,(ox)2(H20)2]-iH20 (1) and of a photoreaction product of 1, namely of single crystals of a 3-dimensional polymeric compound [FeII(bipy)3]2+"[FeII2(ox)3]"* 12"-(2), where ox is oxalate and bipy is 2,2'-bipyridine, have been determined by X-ray diffraction. Crystal data: 1, monoclinic, /lei, a = 7.302(2) A, b = 23.046(3) A, c = 10.361(2) A, ß = 91.12(2)°, Z = 4, R(F0) = 0.040 for 3273 independent data [/ > 3 (/); 2, cubic, P4332, a = 15.392(2) A, Z = 4, R(F0) = 0.050 for 1594 independent data [/ > 3 (/)].[Fen(ox)3/2]-units in 2 build a 3-dimensional anionic network. It can be described as a 3-connected net consisting of 10-gons, wherein the [Fe(bipy)3]2+ cations occupy the vacancies in an elaborate manner. There exist very few examples as yet of inorganic compounds with structures based on 3-dimensional 3-connected nets.

Background Successful management of chronic diseases requires a trustful collaboration between health care professionals, patients, and family members. Scalable conversational agents, designed to assist health care professionals, may play a significant role in supporting this collaboration in a scalable way by reaching out to the everyday lives of patients and their family members. However, to date, it remains unclear whether conversational agents, in such a role, would be accepted and whether they can support this multistakeholder collaboration. Objective With asthma in children representing a relevant target of chronic disease management, this study had the following objectives: (1) to describe the design of MAX, a conversational agent–delivered asthma intervention that supports health care professionals targeting child-parent teams in their everyday lives; and (2) to assess the (a) reach of MAX, (b) conversational agent–patient working alliance, (c) acceptance of MAX, (d) intervention completion rate, (e) cognitive and behavioral outcomes, and (f) human effort and responsiveness of health care professionals in primary and secondary care settings. Methods MAX was designed to increase cognitive skills (ie, knowledge about asthma) and behavioral skills (ie, inhalation technique) in 10-15-year-olds with asthma, and enables support by a health professional and a family member. To this end, three design goals guided the development: (1) to build a conversational agent–patient working alliance; (2) to offer hybrid (human- and conversational agent–supported) ubiquitous coaching; and (3) to provide an intervention with high experiential value. An interdisciplinary team of computer scientists, asthma experts, and young patients with their parents developed the intervention collaboratively. The conversational agent communicates with health care professionals via email, with patients via a mobile chat app, and with a family member via SMS text messaging. A single-arm feasibility study in primary and secondary care settings was performed to assess MAX. Results Results indicated an overall positive evaluation of MAX with respect to its reach (49.5%, 49/99 of recruited and eligible patient-family member teams participated), a strong patient-conversational agent working alliance, and high acceptance by all relevant stakeholders. Moreover, MAX led to improved cognitive and behavioral skills and an intervention completion rate of 75.5%. Family members supported the patients in 269 out of 275 (97.8%) coaching sessions. Most of the conversational turns (99.5%) were conducted between patients and the conversational agent as opposed to between patients and health care professionals, thus indicating the scalability of MAX. In addition, it took health care professionals less than 4 minutes to assess the inhalation technique and 3 days to deliver related feedback to the patients. Several suggestions for improvement were made. Conclusions This study provides the first evidence that conversational agents, designed as mediating social actors involving health care professionals, patients, and family members, are not only accepted in such a “team player” role but also show potential to improve health-relevant outcomes in chronic disease management.

No abstract

Background: The normal left ventricle shows a systolic wringing motion with clockwise rotation at the base and counterclockwise rotation at the apex. Purpose: The aim of the present study was (1) to assess left ventricular (LV) contraction and relaxation in patients with chronic heart failure (CHF), and (2) to evaluate the effect of medical therapy on LV contraction -relaxation behavior. Methods: Magnetic resonance was used to examine LV motion by labeling specific LV regions in three planes (myocardial tagging). Twenty-three subjects were included, nine healthy controls and 14 CHF patients. Cardiac motion was determined from the deformation of a rectangular grid in a basal and apical plane. CHF patients were put on triple therapy with ACE-inhibitors, h-blockers and spironolactone. Follow-up examination (n=9) was performed after 6 months. Results: In controls, systolic rotation was À9.5F2j at the base and +3.3F1j at the apex. In CHF patients, rotation was reduced both at the base (À3.4F2j, P<0.01) and the apex (+0.9F3j, P<0.05). Similarly, regional ejection fraction (REF) was reduced in CHF patients both at the base and the apex. Medical therapy was associated with an improvement in REF, but systolic rotation improved only at the base (À4.6F2j, P<0.05). Conclusions: Systolic wringing motion with clockwise rotation at the base and counterclockwise rotation at the apex is maintained in CHF although reduced. Heart failure treatment is associated with an improvement in REF, whereas rotation improved only at the base, but not at the apex. Thus, there is an uncoupling between regional shortening and rotation in CHF patients.