A tunable magnetic metamaterial based on the dipolar four-state Potts model.

Metamaterials, tunable artificial materials, are useful playgrounds to investigate magnetic systems. So far, artificial Ising spin systems have revealed features such as emergent magnetic monopoles1,2 and charge fragmentation3. Here we present a metasystem composed of a lattice of dipolarly coupled nanomagnets. The magnetic spin of each nanomagnet is constrained to lie along a body diagonal, which yields four possible spin states. We show that the magnetic ordering of this metasystem (antiferromagnetic, ferromagnetic or spin ice like) is determined by the spin states orientation relative to the underlying lattice. The dipolar four-state Potts model explains our experimental observations and sheds light on the role of symmetry, as well as short- and long-range dipolar magnetic interactions, in such non-Ising spin systems.

Thresholdless nanoscale coaxial lasers.

The effects of cavity quantum electrodynamics (QED), caused by the interaction of matter and the electromagnetic field in subwavelength resonant structures, have been the subject of intense research in recent years. The generation of coherent radiation by subwavelength resonant structures has attracted considerable interest, not only as a means of exploring the QED effects that emerge at small volume, but also for its potential in applications ranging from on-chip optical communication to ultrahigh-resolution and high-throughput imaging, sensing and spectroscopy. One such strand of research is aimed at developing the 'ultimate' nanolaser: a scalable, low-threshold, efficient source of radiation that operates at room temperature and occupies a small volume on a chip. Different resonators have been proposed for the realization of such a nanolaser--microdisk and photonic bandgap resonators, and, more recently, metallic, metallo-dielectric and plasmonic resonators. But progress towards realizing the ultimate nanolaser has been hindered by the lack of a systematic approach to scaling down the size of the laser cavity without significantly increasing the threshold power required for lasing. Here we describe a family of coaxial nanostructured cavities that potentially solve the resonator scalability challenge by means of their geometry and metal composition. Using these coaxial nanocavities, we demonstrate the smallest room-temperature, continuous-wave telecommunications-frequency laser to date. In addition, by further modifying the design of these coaxial nanocavities, we achieve thresholdless lasing with a broadband gain medium. In addition to enabling laser applications, these nanoscale resonators should provide a powerful platform for the development of other QED devices and metamaterials in which atom-field interactions generate new functionalities.

Twisted chains of resonant particles: optical polarization control, waveguidance, and radiation.

Linear chains of metallic nanoparticles that are sequentially rotated about the chain axis display interesting polarization-sensitive optical properties. Such twisted chains posses and extend properties of chiral gratings and general periodic gratings. They are characterized by high anisotropy and polarization sensitivity, and have subwavelength transverse dimensions. These structures are shown to support transverse modes with distinct propagation wavenumbers and radiation properties, including slow (bound) and fast (radiative) modes. They also have stop bands of different types, resulting from coupling between distinct transverse modes, as well as coupling with different higher-order diffraction modes.

[Gastrodiscoidosis is a dangerous zoonosis].

The paper gives data on the helminthiasis--gastrodiscoidosis, a zoonotic disease caused by the trematode Gastrodiscoides hominis (Lewis et McConnall, 1876) parasitizing in the animal and human intestine in the endemic foci of both Russia and foreign countries. It also presents information on the morphology of the helminth, the biological cycle of development of the parasite and its habitat and spread, as well as its induced abnormalities and on the method of diagnosing of the disease.

[Use of checkpoints method in medico-social and organization studies].

The method of checkpoints proposed by authors is proposed to be used in practice. Economic and rational features of this technique of static handling and data collection make it advisable to apply.

Physical source realization of complex source pulsed beams

Complex source pulsed beams (CSPB) are exact wave-packet solutions of the time-dependent wave equation that are modeled mathematically in terms of radiation from a pulsed point source located at a complex space-time coordinate. In the present paper, the physical source realization of the CSPB is explored. This is done in the framework of the acoustic field, as a concrete physical example, but a similar analysis can be applied for electromagnetic CSPB. The physical realization of the CSPB is addressed by deriving exact expressions for the acoustic source distribution in the real coordinate space that generates the CSPB, and by exploring the power and energy flux near these sources. The exact source distribution is of finite support. Special emphasis is placed on deriving simplified source functions and parametrization for the special case where the CSPB are well collimated.

[A course of coronary heart disease and quality of life in patients with varying depressive states]. / Osobennosti techeniia ischemicheskoi bolezni i kachestvo zhizni bol'nykh s depressivnymi rasstroistvami razlichnogo urovnia.

AIM: To study a course of coronary heart disease (CHD) in patients with depressive disorders. MATERIAL AND METHODS: The trial included 77 CHD patients aged 39 to 68 years (mean age 54.9 +/- 0.9 years), 40 (51.9%) of them had myocardial infarction. All the examinees had effort angina of functional class II-IV by criteria of the Canadian Cardiology Association. All the patients have undergone standard clinical examination, stress tests, coronaroangiography (n = 30), assessment of the degree of vegetative dystonia and quality of life. The patients were divided into two groups depending on the depression degree. RESULTS: CHD patients with manifest depression vs those with subclinical depression had a higher level of personality and reactive anxiety. They had neurotic and psychopathological personality alterations associated with more pronounced vegetative disorders. These patients suffered from more severe coronary atherosclerosis, more hospitalizations for the previous year, more myocardial infarctions, lower physical activity and quality of life. CONCLUSION: CHD patients with manifest depression have lower physical performance and quality of life though this is not confirmed at exercise tests.

[Automatic regulation and central hemodynamics in patients with postinfarct cardiosclerosis and heart failure]. / Vegetativnaia reguliatsiia i tsentral'naia gemodinamika pri ortoprobe u bol'nykh s postinfarktnym kardiosklerozom i serdechnoi nedostatochnost'iu.

The study was undertaken to examine the specific features of autonomic regulation and the parameters of central hemodynamics in patients with postinfarct cardiosclerosis (PICS) and circulatory insufficiency who had different types of left ventricular remodelling (LVR). Thirty-two patients with PICS and heart failure (HF) were examined. The autonomic status was studied, by analyzing cardiac rhythm variability (CRV) from 5-min resting cardiointervalograms and by the cardiovascular tests described by D. Y. Ewing; integral rheography was also performed. The patients were divided into 2 groups according to the type of LVR. Patients with PICS + HF and concentric LVR were found to have a more balanced autonomic circulatory regulation and a hemodynamic type that was more energetically efficient for the myocardium. Those with PICS + HF and eccentric LVR had a hemodynamic type that was less efficient for the myocardium, which was accompanied by the enhanced activity of the sympathetic nervous system (SNS) even at resting. Patients with PICS + HF, particularly in the presence of the latter's higher functional class and eccentric LVR, seemed to have desensitized adrenoceptors and impaired baroreflex activity, as appeared as no rise in peripheral vascular resistance with the enhanced sympathetic activity. The findings support the expediency of using beta-adrenoblockers in HF in patients with PICS, particularly with eccentric LVR. Analysis of cardiac rhythm variability is sufficiently informative in evaluating autonomic regulation and autonomic balance, SNS tone in particular, in patients with HF.

[Integrated assessment and models of the functional system of medical care delivered to patients with sexually transmitted diseases]. / Kompleksna otsinka ta modeli funktsionuvannia systemy medychnoï dopomohy khvorym z venerychnymy zakhvoriuvanniamy.

The article presents the issue of organizing medical care to patients with sexually transmitted diseases: There were developed and proposed into practical health care system indices for evaluating organization of rendering medical care. The theory of imitation modeling and mass service was proposed to calculate necessary bedspace that can optimize specialized medical care expenditure.

Optical waves on nanoparticle chains coupled with surfaces.

Linear chains of metal nanoparticles coupled with dielectric surfaces support a variety of optical phenomena including traveling and leaky waves of several types. We investigate the chain-surface interactions and show that traveling waves can remain bound to the chain, radiate into surface wave beams, or radiate into space and surface wave beams. Radiation into surface waves may be exploited to create a leaky surface wave antenna with potential applications to surface wave microscopy.