Tuning Ferromagnetism in a Single Layer of Fe above Room Temperature

The crystallographic and magnetic properties of an Fe monolayer (ML) grown on 2 ML Au/W(110) substrate are studied with spin-polarized low-energy electron microscopy, density functional theory, and relativistic screened Korringa–Kohn–Rostoker calculations. The single layer of iron atoms possesses hexagonal symmetry and reveals a ferromagnetic order at room temperature. We experimentally demonstrate the possibility of tuning the Curie temperature and the magnitude of magnetization of the Fe monolayer by capping with Au. Taking into account several structural models, the calculation results mostly show ferromagnetic states with enhanced magnetic moments of Fe atoms compared to their bulk value and a further increase in their value after covering with Au. The theoretically calculated Curie temperatures are in fair agreement with those obtained in the experiments. The calculations, furthermore, found evidence for the presence of frustrated isotropic Fe–Fe exchange interactions, and a discussion of the structural effects on the magnetic properties is provided herein

Supramolecular organization of liquid-crystal dimers-bis-cyanobiphenyl alkanes on HOPG by scanning tunneling microscopy

2D supramolecular organization of a series of six cyanobiphenyl bimesogens deposited on highly oriented pyrolytic graphite (HOPG) is studied by scanning tunneling microscopy (STM). The adsorbatesare 1,ω-bis(4-cyanobiphenyl-4’-yl)alkanes (CBnCB) with different length of their flexible alkyl spacer (containing 7 to 12 methylene groups). Microscopic investigations at the molecular resolution allow fordetailed analysis of the effect of the alkyl spacer length on the type and the extent of the resulting 2Dorganization. It has been demonstrated that bimesogens with shorter spacers (7 and 8 methylene units)organize in a similar manner characterized by the formation of two types of differently ordered monolayers: dense packed, wherein the molecules are oriented in one direction and ordered into parallel rows(layer structure), or less densely packed wherein they are organized into a chiral windmill-like structure. For derivatives with longer spacers (ranging from 9 to 12 methylene units) additional effect of parity of carbon atoms in the spacer (even versus odd) is observed. In this range of the spacer length even membered bimesogens are still organized in a typical layer structure. However, odd-membered dimers exhibit a much complex 2D supramolecular organization with a larger unit cell and a helical arrangement of the molecules. Careful comparison of this structure with the 3D structural data derived from the X-ray diffraction investigations of single crystals indicates that for these bimesogens a clear correlation exists between the observed complex 2D supramolecular organization in the monolayer and the organization in one of the crystallographic planes of the 3D nematic twist-bent phas

Supramolecular organization of liquid-crystal dimers-bis-cyanobiphenyl alkanes on HOPG by scanning tunneling microscopy

2D supramolecular organization of a series of six cyanobiphenyl bimesogens deposited on highly oriented pyrolytic graphite (HOPG) is studied by scanning tunneling microscopy (STM). The adsorbatesare 1,ω-bis(4-cyanobiphenyl-4’-yl)alkanes (CBnCB) with different length of their flexible alkyl spacer (containing 7 to 12 methylene groups). Microscopic investigations at the molecular resolution allow fordetailed analysis of the effect of the alkyl spacer length on the type and the extent of the resulting 2Dorganization. It has been demonstrated that bimesogens with shorter spacers (7 and 8 methylene units)organize in a similar manner characterized by the formation of two types of differently ordered monolayers: dense packed, wherein the molecules are oriented in one direction and ordered into parallel rows(layer structure), or less densely packed wherein they are organized into a chiral windmill-like structure. For derivatives with longer spacers (ranging from 9 to 12 methylene units) additional effect of parity of carbon atoms in the spacer (even versus odd) is observed. In this range of the spacer length even membered bimesogens are still organized in a typical layer structure. However, odd-membered dimers exhibit a much complex 2D supramolecular organization with a larger unit cell and a helical arrangement of the molecules. Careful comparison of this structure with the 3D structural data derived from the X-ray diffraction investigations of single crystals indicates that for these bimesogens a clear correlation exists between the observed complex 2D supramolecular organization in the monolayer and the organization in one of the crystallographic planes of the 3D nematic twist-bent phas

Temperature-Dependent Growth and Evolution of Silicene on Au Ultrathin Films—LEEM and LEED Studies

The formation and evolution of silicene on ultrathin Au films have been investigated with low energy electron microscopy and diffraction. Careful control of the annealing rate and temperature of Au films epitaxially grown on the Si(111) surface allows for the preparation of a large scale, of the order of cm2, silicene sheets. Depending on the final temperature, three stages of silicene evolution can be distinguished: (i) the growth of the low buckled phase, (ii) the formation of a layered heterostructure of the low buckled and planar phases of silicene and (iii) the gradual destruction of the silicene. Each stage is characterized by its unique surface morphology and characteristic diffraction patterns. The present study gives an overview of structures formed on the surface of ultrathin Au films and morphology changes between room temperature and the temperature at which the formation of Au droplets on the Si(111) surface occurs

The Influence of Frailty Syndrome and Dementia on the Convenience and Satisfaction with Oral Anticoagulation Treatment in Elderly Patients with Atrial Fibrillation

Background: The impact of frailty syndrome (FS) and dementia on the convenience and satisfaction with oral anticoagulation (OAC) treatment in atrial fibrillation (AF) patients is not well-known. Aim: Assessment the impact of FS and dementia on the convenience and satisfaction with OAC treatment in 116 elderly (mean age 75.2, SD = 8.2) patients with AF. Methodology: A self-administered questionnaire was used in the study to collect basic socio-demographic and clinical data. Tilburg Frailty Indicator (TFI) questionnaire was used to assess the presence of FS, Mini Mental State Examination (MMSE) to assess cognitive impairment (CI), The Perception of Anticoagulant Treatment Questionnaire Part 2 (PACT-Q2) to assess convenience and satisfaction with OAC treatment, and the Arrhythmia-Specific Questionnaire in Tachycardia and Arrhythmia (ASTA) to assess quality of life (QoL). Results: Multivariable analysis as a significant, negative predictor of the convenience and satisfaction domain showed the occurrence of dementia (β = −0.34; p < 0.001, β = −0.41; p < 0.001, respectively) and prior major bleeding (β = −0.30; p < 0.001, β = −0.33; p < 0.001, respectively). Analysis showed a significant relationship between convenience and satisfaction and the overall result of the ASTA (r = −0.329; p < 0.001, r = −0.372; p < 0.001, respectively). Conclusions: Elements of geriatric syndrome, such as FS and dementia, adversely affect treatment convenience and satisfaction with OAC treatment in AF. It has been shown that better convenience and satisfaction with OAC treatment translates into better QoL. There were no differences between satisfaction and convenience and the type of OAC treatment (vitamin K antagonists (VKA) vs. novel oral anticoagulants (NOAC)

Soluble Flavanthrone Derivatives: Synthesis, Characterization, and Application to Organic Light-Emitting Diodes

Simple modification of benzo[h]benz[5,6]acridino[2,1,9,8-klmna]acridine-8,16-dione, an old and almost-forgotten vat dye, by reduction of its carbonyl groups and subsequent O-alkylation, yields solution-processable, electroactive, conjugated compounds of the periazaacene type, suitable for the use in organic electronics. Their electrochemically determined ionization potential and electron affinity of about 5.2 and −3.2 eV, respectively, are essentially independent of the length of the alkoxyl substituent and in good agreement with DFT calculations. The crystal structure of 8,16-dioctyloxybenzo[h]benz[5,6]acridino[2,1,9,8-klmna]acridine (FC-8), the most promising compound, was solved. It crystallizes in space group Pmath formula and forms π-stacked columns held together in the 3D structure by dispersion forces, mainly between interdigitated alkyl chains. Molecules of FC-8 have a strong tendency to self-organize in monolayers deposited on a highly oriented pyrolytic graphite surface, as observed by STM. 8,16-Dialkoxybenzo[h]benz[5,6]acridino[2,1,9,8-klmna]acridines are highly luminescent, and all have photoluminescence quantum yields of about 80 %. They show efficient electroluminescence, and can be used as guest molecules with a 4,4′-bis(N-carbazolyl)-1,1′-biphenyl host in guest/host-type organic light-emitting diodes. The best fabricated diodes showed a luminance of about 1900 cd m−12, a luminance efficiency of about 3 cd A−1, and external quantum efficiencies exceeding 0.9 %

Pol-CDRIE registry – 1-year observational data on patients hospitalized due to cardiac device-related infective endocarditis in Polish referential cardiology centres

Background: The rate of cardiac device–related infective endocarditis (CDRIE) is increasing worldwide, but no detailed data are available for Poland. Aims: We aimed to evaluate clinical, diagnostic, and therapeutic data of patients hospitalized due to CDRIE in 22 Polish referential cardiology centers from May 1, 2016 to May 1, 2017. Methods: Participating cardiology departments were asked to fill in a questionnaire that included data on the number of hospitalized patients, number and types of implanted cardiac electrotherapy devices, and number of infective endocarditis cases. We also collected clinical data and data regarding the management of patients with CDRIE. Results: Overall, 99 621 hospitalizations were reported. Infective endocarditis unrelated to cardiac device was the cause of 596 admissions (0.6%), and CDRIE, of 195 (0.2%). Pacemaker was implanted in 91 patients with CDRIE (47%); cardioverter‑defibrillator, in 51 (26%); cardiac resynchronization therapy‑defibrillator, in 48 (25%); and cardiac resynchronization therapy‑pacemaker, in 5 (2.5%). The most common symptoms were malaise (62%), fever/chills (61%), cough (21%), chest pain (19.5%), and inflammation of the device pocket (5.6%). Cultures were positive in 77.5% of patients. The cardiac device was removed in 91% of patients. The percutaneous approach was most common for cardiac device removal. All patients received antibiotic therapy, and 3 patients underwent a heart valve procedure. Transesophageal echocardiography was performed in 80% of patients. The most common complication was heart failure (25% of patients). Conclusions: The clinical profile, pathogen types, and management strategies in Polish patients with CDRIE are consistent with similar data from other European countries. Transesophageal echocardiography was performed less frequently than recommended. The removal rate in the Polish population is consistent with the general rates observed for interventional treatment in patients with CDRIE

Self-Assembly Properties of Semiconducting Donor–Acceptor–Donor Bithienyl Derivatives of Tetrazine and ThiadiazoleEffect of the Electron Accepting Central Ring

Scanning tunneling microscopy was used to study the effect of the electron-accepting unit and the alkyl substituent’s position on the type and extent of 2D supramolecular organization of penta-ring donor–acceptor–donor (DAD) semiconductors, consisting of either tetrazine or thiadiazole central acceptor ring symmetrically attached to two bithienyl groups. Microscopic observations of monomolecular layers on HOPG of four alkyl derivatives of the studied adsorbates indicate significant differences in their 2D organizations. Ordered monolayers of thiadiazole derivatives are relatively loose and, independent of the position of alkyl substituents, characterized by large intermolecular separation of acceptor units in the adjacent molecules located in the face-to-face configuration. The 2D supramolecular architecture in both derivatives of thiadiazole is very sensitive to the alkyl substituent’s position. Significantly different behavior is observed for derivatives of tetrazine (which is a stronger electron acceptor). Stronger intermolecular DA interactions in these adsorbates generate an intermolecular shift in the monolayer, which is a dominant factor determining the 2D structural organization. As a consequence of this molecular arrangement, tetrazine groups (A segments) face thiophene rings (D segments) of the neighboring molecules. Monolayers of tetrazine derivatives are therefore much more densely packed and characterized by similar π-stacking of molecules independently of the position of alkyl substituents. Moreover, a comparative study of 3D supramolecular organization, deduced from the X-ray diffraction patterns, is also presented clearly confirming the polymorphism of the studied adsorbates

Structural, Spectroscopic, Electrochemical, and Electroluminescent Properties of Tetraalkoxydinaphthophenazines: New Solution-Processable Nonlinear Azaacenes

A series of solution-processable tetraalkoxy-substituted dinaphtho­[2,3-<i>a</i>:2′,3′-<i>h</i>]­phenazines were synthesized by reductive functionalization of indanthrone (6,15-dihydrodinaphtho­[2,3-<i>a</i>:2′,3′-<i>h</i>]­phenazine-5,9,14,18-tetraone), an old intractable dye. The melting point of these new compounds was found to decrease from 204 °C to 98 °C upon extension of the number of carbons from 4 to 12 in the alkoxy substituent. All derivatives show a strong tendency to self-organize in 2D as evidenced by STM investigations of monolayers deposited on HOPG. The 2D structure is less dense and shows different alkoxy group interdigitation pattern as compared to the 3D structure determined from the X-ray diffraction data obtained for the corresponding single crystals. Electrochemical, absorption, and emission properties of tetraalkoxy-substituted dinaphtho­[2,3-<i>a</i>:2′,3′-<i>h</i>]­phenazines, studied in solution, are essentially independent of the length of the alkoxy substituents. All derivatives exhibit high photoluminescence quantum yield, approaching 60%. When molecularly dispersed in a solid matrix consisting of poly­(9-vinylcarbazole) (PVK) (60 wt %) and (2-<i>tert</i>-butylphenyl-5-biphenyl-1,3,4-oxadiazole) (PBD) (40 wt %) (so-called “guest/host configuration”), they show green electroluminescence due to an effective energy transfer from the matrix to the luminophore. The best light-emitting diodes were obtained for the butoxy derivative showing a luminance approaching 1500 cd/m² and a luminous efficiency over 0.8 cd/A