[Gas in superior mesenteric artery and celiac axis as a rare CT-sign of extensive bowel necrosis].

The authors report endovascular treatment of acute thromboembolic occlusion of superior mesenteric artery in a 75-year-old patient whose postoperative period was complicated by massive reperfusion and translocation syndrome. Contrast-enhanced CT in 12 hours after successful thrombectomy from superior mesenteric artery revealed CT signs of irreversible bowel lesion, i.e.

[Endovascular surgery for acute mesenteric ischemia].

Objective: To demonstrate the results of endovascular treatment of 15 patients with acute mesenteric ischemia.

Material And Methods: There were 15 patients with acute mesenteric ischemia who underwent surgery (9 men and 6 women). Mean age was 77±11 years.

[Diagnosis and treatment of extracranial internal carotid artery lesion combined with cerebrovascular malformation].

Aim: To analyze own experience of diagnosis and treatment of patients with extracranial internal carotid artery lesion and cerebrovascular malformations.

Material And Methods: There were 16 patients with combined lesion of extracranial and intracranial internal carotid artery for the period January 2013 - December 2014. Occlusive-stenotic lesion and tortuosity of ICA were observed in 11 and 5 cases respectively.

[Early reconstruction of brachiocephalic arteries as a prevention of recurrent ischemic stroke].

Aim: To assess an efficacy and safety of brachiocephalic arteries reconstruction at the acute stage of stroke.

Material And Methods: Early reconstruction of brachiocephalic arteries was made in 7 patients (mean age 67±9 years). Mean terms of brachiocephalic arteries reconstruction after stroke were 4.

[Early reconstruction of supra-aortic vessels as a prevention of recurrent ischemic stroke].

Aim: To evaluate the efficacy and safety of supra-aortic vessels reconstruction within acute period of stroke.

Material And Methods: Early surgery was performed in 7 patients aged 67±9 years. Revascularization was made after 4.

Non-degenerate 2-photon excitation in scattering medium for fluorescence microscopy.

Non-degenerate 2-photon excitation (ND-2PE) of a fluorophore with two laser beams of different photon energies offers an independent degree of freedom in tuning of the photon flux for each beam. This feature takes advantage of the infrared wavelengths used in degenerate 3-photon excitation (D-3PE) microscopy to achieve increased penetration depths, while preserving a relatively high 2-photon excitation cross section in comparison to that of D-3PE. Here, using spatially and temporally aligned Ti:Sapphire laser and optical parametric oscillator beams operating at near infrared (NIR) and short-wavelength infrared (SWIR) optical frequencies, we employ ND-2PE and provide a practical demonstration that a constant fluorophore emission intensity is achievable deeper into a scattering medium using ND-2PE as compared to the commonly used degenerate 2-photon excitation (D-2PE).

Cell type specificity of neurovascular coupling in cerebral cortex.

Identification of the cellular players and molecular messengers that communicate neuronal activity to the vasculature driving cerebral hemodynamics is important for (1) the basic understanding of cerebrovascular regulation and (2) interpretation of functional Magnetic Resonance Imaging (fMRI) signals. Using a combination of optogenetic stimulation and 2-photon imaging in mice, we demonstrate that selective activation of cortical excitation and inhibition elicits distinct vascular responses and identify the vasoconstrictive mechanism as Neuropeptide Y (NPY) acting on Y1 receptors. The latter implies that task-related negative Blood Oxygenation Level Dependent (BOLD) fMRI signals in the cerebral cortex under normal physiological conditions may be mainly driven by the NPY-positive inhibitory neurons.

[Endovascular interventions for acute ischemia of intestine].

It is presented 5 clinical observations of acute ischemia of intestine in which different endovascular interventions including isolated superior mesenteric artery stenting, rheolytic and aspiration thrombectomy and combination of techniques were applied. Surgical success with blood flow restoration in superior mesenteric artery was achieved in 4 of 5 patients. 2 patients have required laparotomy and intestinal resection.

Composite dielectric metasurfaces for phase control of vector field.

We designed, fabricated, and characterized a dielectric metamaterial lens created by varying the density of subwavelength low refractive index nanoholes in a high refractive index substrate, resulting in a locally variable effective refraction index. It is shown that a constructed graded index lens can overcome diffraction effects even when the aperture/wavelength (D/λ) ratio is smaller than 40. In addition to the conventional design of a polarization insensitive lens, we also show that a polarization diversity lens (f(o)≠f(e)) can be realized by arranging nanoholes in patterns with variable density in different transverse directions.

[Experience in diagnosis and treatment of combined lesions of the extra- and intracranial portions of the internal carotid artery].

The treatment policy concerning patients with lesions of the extra- and intracranial portions of carotid arteries is currently uncertain. The authors share herein their experience in diagnosis and treatment of 5 patients presenting with lesions of the extracranial portions of the internal carotid artery (stenosis/occlusion/pathological tortuosity) combined with arterial aneurysms and arteriovenous malformations of the brain. Of these, two patients were operated on: the first one was primarily subjected to clipping of the cerebral aneurysm then after several months underwent a reconstructive vascular operation on the ipsilateral side (resection of the internal carotid artery with its readdressing).

Broadband metacoaxial nanoantenna for metasurface and sensing applications.

We introduce a metacoaxial nanoantenna (MN) that super-localizes the incident electromagnetic field to "hotspots" with a top-down area of 2 nm(2), a local field enhancement of ~200-400, and a field localization with a very large spectral range from the visible to the infrared range that has a spectral bandwidth ≥ 900 nm. Not only is this nanoantenna extremely broadband with ultra-high localization, it also shows significant improvements over traditional nanoantenna designs, as the hotspots are re-configurable by breaking the circular symmetry which enables the ability to tailor the polarization response. These attributes offer significant improvements over traditional nanoantennas as building blocks for metasurfaces and enhanced biodetection that we demonstrate in this work.

Nanoscale imaging of photocurrent and efficiency in CdTe solar cells.

The local collection characteristics of grain interiors and grain boundaries in thin-film CdTe polycrystalline solar cells are investigated using scanning photocurrent microscopy. The carriers are locally generated by light injected through a small aperture (50-300 nm) of a near-field scanning optical microscope in an illumination mode. Possible influence of rough surface topography on light coupling is examined and eliminated by sculpting smooth wedges on the granular CdTe surface.

[Modern approach to diagnosis and treatment of acute mesenteric ischemia].

It was proposed the medical and diagnostic tactic in patients with acute mesenteric ischemia on basis of efficiency results of modern laboratory markers and instrumental methods. Positive laboratory D-dimer-test with computed tomography of abdominal organs or abdominal aorta and its branches CT-angiography led to diagnose thrombosis or embolism of mesenteric arteries at early terms and to reduce preoperative period. The authors presented the variant of isolated endovascular intervention in case of superior mesenteric artery thrombosis.

[Venous thromboembolic complications in patients with intracranial hemorrhage and tumors of the central nervous system].

It was analyzed the results of diagnosis and prevention of venous thromboembolic complications in 248 patients with intracranial hemorrhages of different etiology (hemorrhagic stroke, subarachnoid hemorrhage, craniocerebral injury, hemorrhages in the tumors of brain and spinal cord). The overall frequency of venous thrombosis in the vessels of the inferior vena cava pool was 24.6% (in 61 patients), the majority of patients had the asymptomatic thrombosis.

Tensor of the second-order nonlinear susceptibility in asymmetrically strained silicon waveguides: analysis and experimental validation.

We theoretically consider the existence of multiple nonzero components of the second-order nonlinear susceptibility tensor, χ(2), generated via strain-induced symmetry breaking in crystalline silicon. We determine that, in addition to the previously reported χ(xxy)(2) component, the χ(yyy)(2) component also becomes nonzero based on the remaining symmetry present in the strained material. In order to characterize these two nonlinearities, we fabricate Fabry-Perot waveguide resonators on 250 nm thick silicon-on-insulator wafers clad with 180 nm of compressively stressed (-1.

[Sural sinus as the main source of postoperative venous thromboembolic complications in neurosurgical patients].

The authors analysed the results of diagnosis and treatment of venous thromboembolic complications in a total of 239 patients presenting with various-aetiology intracranial haemorrhage and tumours of the central system. The total incidence of venous thromboses in the system of the inferior vena cava amounted to 25.1%.

All-angle negative refraction and active flat lensing of ultraviolet light.

Decades ago, Veselago predicted that a material with simultaneously negative electric and magnetic polarization responses would yield a 'left-handed' medium in which light propagates with opposite phase and energy velocities--a condition described by a negative refractive index. He proposed that a flat slab of left-handed material possessing an isotropic refractive index of -1 could act like an imaging lens in free space. Left-handed materials do not occur naturally, and it has only recently become possible to achieve a left-handed response using metamaterials, that is, electromagnetic structures engineered on subwavelength scales to elicit tailored polarization responses.

[The possibilities of laser Doppler flowmetry for the estimation of the intestine resection volume by the acute mesenteric ischemia].

The results of the surgical treatment of the acute mesenteric ischemia in 2 groups of patients were comparatively analyzed. The control group (n=52) experienced the traditional way and criteria of detecting the volume of intestinal resection (color and peristaltic activity, arterial pulsation). For the main group (n=57) the intraoperative estimation of the intestinal viability was performed with the help of laser Doppler flowmetry.

[Safety and efficacy of various regimens of heparin-mediated prevention of venous thromboses in patients with intracranial haemorrhage].

Analysed in the article is the incidence rate of the development of venous thromboembolic complications in a total of 79 patients presenting with various-aetiology intracranial haemorrhage in different regimens of heparin-mediated prevention. The authors have revealed that early (on day 2-4 after the onset of the disease) administration of preventive doses of heparin in patients with intracerebral and intracranial haematomas is a safe and efficient regimen, since it decreases the rate of venous thromboses in the system of the vena cava inferior and fatal thromboembolic complications as compared with a later term (on day 5 and more) of initiating heparin-mediated prevention.

[Major intestinal resections and short-bowel syndrome in patients with the acute mesenterial thrombosis].

The study represents the retrospective analysis of major intestinal resections (the length of the left in olace bowel less then 200 sm) and non-major resections in 52 patients operated on the acute mesenterial thrombosis. Major bowel resection was performed in 30 patients (57.7%).

Near-field measurement of amplitude and phase in silicon waveguides with liquid cladding.

Heterodyne near-field scanning optical microscopy (H-NSOM) has proven useful as a tool for characterization of both amplitude and phase of on-chip photonic devices in air, but it has previously been unable to characterize devices with a dielectric overcladding, which is commonly used in practice for such devices. Here we demonstrate H-NSOM of a silicon waveguide with a liquid cladding emulating the solid dielectric. This technique allows characterization of practical devices with realistic refractive index profiles.

[Intestinal microcirculation in health and in acute impairment of mesenteric blood flow].

The authors attempted to determine instrumental criteria for vitality and non-vitality of the intestine with the help of laser Doppler flowmetry and absorption spectroscopy. The material used was subdivided into two study groups: in group one, the indices of microcirculation of the viable small and large intestine were determined during elective cavitary operations; group two comprised 20 portions of resected necrotised segments of the large and small intestine, wherein we registered the indices of microcirculation of the non-viable devitalized intestine. We thus obtained instrumental indices of microcirculation of various intestinal portions in health, as well as in the setting of acute impairment of intestinal blood circulation and intestinal gangrene.

Heterodyne near-field scanning optical microscopy with spectrally broad sources.

We propose to use low-coherence-length cw optical sources with a broad spectrum in heterodyne near-field scanning microscopy in order to imitate optical pulse propagation and to obtain information about spectrally variant properties of nanophotonic components. The dispersion difference in the interferometer arms for a symmetric acousto-optic modulator arrangement is shown to be negligible over appreciable bandwidths. Demonstration of the principle of operation and viability of this approach is provided by measurement of the group refractive index of a silicon channel waveguide.

Nanoscale optical field localization by resonantly focused plasmons.

We experimentally demonstrate use of plasmonic resonant phenomena combined with strong field localization to enhance efficiency of confining optical fields in a Si waveguide. Our approach utilizes a plasmonic resonant nano-focusing-antenna (RNFA), that simultaneously supports several focusing mechanisms in a single nanostructure, integrated with a lossless Si waveguide utilized with silicon-on-insulator (SOI) technology, to achieve a sub-diffraction limited focusing with a nanoscale (deeply subwavelength) spot size. The metallic RNFA effectively converts an incoming propagating waveguide mode to a localized resonant plasmon mode in an ultrasmall volume in all 3 dimensions.

Effects produced by metal-coated near-field probes on the performance of silicon waveguides and resonators.

We study the effects of metal-coated fiber near-field probes on the performance of nanophotonic devices. Employing a heterodyne near-field scanning optical microscope and analyzing transmission characteristics, we find that a metal-coated probe can typically introduce a 3 dB intensity loss and a 0.2 rad phase shift during characterization of a straight waveguide made in a silicon-on-insulator system.