Regional geographies and public health lessons of the COVID-19 pandemic in the Arctic.

Objectives: This study examines the COVID-19 pandemic's spatiotemporal dynamics in 52 sub-regions in eight Arctic states. This study further investigates the potential impact of early vaccination coverage on subsequent COVID-19 outcomes within these regions, potentially revealing public health insights of global significance.

Methods: We assessed the outcomes of the COVID-19 pandemic in Arctic sub-regions using three key epidemiological variables: confirmed cases, confirmed deaths, and case fatality ratio (CFR), along with vaccination rates to evaluate the effectiveness of the early vaccination campaign on the later dynamics of COVID-19 outcomes in these regions.

Depth-resolved method for attenuation coefficient calculation from optical coherence tomography data for improved biological structure visualization.

Optical coherence tomography (OCT) is a promising tool for intraoperative tissue morphology determination. Several studies suggest that attenuation coefficient derived from the OCT images, can differentiate between tissues of different morphology, such as normal and pathological structures of the brain, skin, and other tissues. In the present study, the depth-resolved method for attenuation coefficient calculation was adopted for the real-world situation of the depth-dependent OCT sensitivity and additive imaging noise with nonzero mean.

Incorporating resilience when assessing pandemic risk in the Arctic: a case study of Alaska.

The discourse on vulnerability to COVID-19 or any other pandemic is about the susceptibility to the effects of disease outbreaks. Over time, vulnerability has been assessed through various indices calculated using a confluence of societal factors. However, categorising Arctic communities, without considering their socioeconomic, cultural and demographic uniqueness, into the high and low continuum of vulnerability using universal indicators will undoubtedly result in the underestimation of the communities' capacity to withstand and recover from pandemic exposure.

The second year of pandemic in the Arctic: examining spatiotemporal dynamics of the COVID-19 "Delta wave" in Arctic regions in 2021.

The second year of the COVID-19 pandemic in the Arctic was dominated by the Delta wave that primarily lasted between July and December 2021 with varied epidemiological outcomes. An analysis of the Arctic's subnational COVID-19 data revealed a massive increase in cases and deaths across all its jurisdictions but at varying time periods. However, the case fatality ratio (CFR) in most Arctic regions did not rise dramatically and was below national levels (except in Northern Russia).

Numerical method for axial motion artifact correction in retinal spectral-domain optical coherence tomography.

A numerical method that compensates image distortions caused by random fluctuations of the distance to an object in spectral-domain optical coherence tomography (SD OCT) has been proposed and verified experimentally. The proposed method is based on the analysis of the phase shifts between adjacent scans that are caused by micrometer-scale displacements and the subsequent compensation for the displacements through phase-frequency correction in the spectral space. The efficiency of the method is demonstrated in model experiments with harmonic and random movements of a scattering object as well as during in vivo imaging of the retina of the human eye.

[Non-contact optical coherence tomography - an effective method for visualizing the exudate of the middle ear].

Introduction: Otitis media with effusion (OME) accounts for 15-17% of the total number of recorded diseases of the middle ear. Surgical methods have become much more common. One of the factors affecting the tactics and effectiveness of treatment OME is the degree of viscosity of the effusion.

Accurate early prediction of tumour response to PDT using optical coherence angiography.

Prediction of tumour treatment response may play a crucial role in therapy selection and optimization of its delivery parameters. Here we use optical coherence angiography (OCA) as a minimally-invasive, label-free, real-time bioimaging method to visualize normal and pathological perfused vessels and monitor treatment response following vascular-targeted photodynamic therapy (PDT). Preclinical results are reported in a convenient experimental model (CT-26 colon tumour inoculated in murine ear), enabling controlled PDT and post-treatment OCA monitoring.

Optical coherence tomography-based angiography device with real-time angiography B-scans visualization and hand-held probe for everyday clinical use.

This work is dedicated to the development of the OCT system with angiography for everyday clinical use. Two major problems were solved during the development: compensation of specific natural tissue displacements, induced by contact scanning mode and physiological motion of patients (eg, respiratory and cardiac motions) and online visualization of vessel cross-sections to provide feedback for the system operator.

In-vivo longitudinal imaging of microvascular changes in irradiated oral mucosa of radiotherapy cancer patients using optical coherence tomography.

Mucositis is the limiting toxicity of radio(chemo)therapy of head and neck cancer. Diagnostics, prophylaxis and correction of this condition demand new accurate and objective approaches. Here we report on an in vivo longitudinal monitoring of the oral mucosa dynamics in 25 patients during the course of radiotherapy of oropharyngeal and nasopharyngeal cancer using multifunctional optical coherence tomography (OCT).

Hybrid M-mode-like OCT imaging of three-dimensional microvasculature in vivo using reference-free processing of complex valued B-scans.

We propose a novel OCT-based method for visualizing microvasculature in three-dimension using reference-free processing of individual complex valued B-scans with highly overlapped A-scans. In the lateral direction of such a B-scan, the amplitude and phase of speckles corresponding to vessel regions exhibit faster variability and, thus, can be detected without comparison with other B-scans recorded in the same plane. This method combines elements of several existing OCT angiographic approaches and exhibits: (1) enhanced robustness with respect to bulk tissue motion with frequencies up to tens of Hz, (2) resolution of microcirculation images equal to that of structural images, and (3) possibility of quantifying the vessels in terms of their decorrelation rates.

[Simultaneous operative interventions in conditions of urgent abdominal surgery].

The experience of performance of urgent simultant operations (SO) on abdominal cavity organs in 63 patients (of them in 12--using laparoscopic technologies) was summarized. The material was compared and analyzed using statistical methods in three clinical groups, suffering concomitant surgical diseases in patients of gastroenterological, coloproctological and herniological profile. There were shown the possibilities and proved the expediency of SO performance in environment of the abdominal cavity urgent surgery in multiprofile general surgery clinic for enhancement of the patients treatment and an optimal surgical tactics choice.

[Simultant operative interventions in elective surgery of abdominal cavity].

The literature data concerning the problem of simultant operative interventions were analyzed and the unsolved topics were delineated. Basing on the detailed analysis of results of the operations obtained in 78 patients, performed for coexistent diseases, the authors consider the simultant operative interventions in elective surgery of the abdominal cavity the method of choice in presence of two-three coexistent diseases, which must be surgically treated.

[The functional status of esophago-gastric transition segment in patients with burns of esophagus].

We examined 57 patients with burns of esophagus at the age of 18-76 years old. We analyzed the symptoms and medical history of the patients, used contrast X-ray examination, endoscopic imaging with biopsy of esophagogastric crossing, the test for gastroesophageal reflux, gastric intubation and pH-metry. The advanced gastroesophageal reflux was registered 1.

[Outcome prognosis of esophagoplasty of esophagus burns with colonic segment ].

Peculiarities of postburn esophagitis course and subsequent rehabilitation of patients with burn of esophagus were studied. The authors had systematized and proposed classification of postburn esophagitis, considering prognosis of autoplastic results using segment of colon for postburn esophageal impassability. Right calculation and logical interpretation, determination of significance of postburn esophagitis will provide success of autoplastic rehabilitation of patients with burn disease of the esophagus.

[Metachronous megacolon and colonic cancer in adults].

The experience of treatment of 9 patients with metachronous megacolon and colonic cancer was analyzed. Clinical signs of the disease are diverse. Radical surgical intervention is singularis method of treatment of such patients.

[Prevention of postoperative recurrence of gastric and duodenal ulcer].

The treatment effectiveness of 913 patients with postoperative recurrence of gastric and duodenal ulcer was studied. The peculiarities of reoperation conduction, application of prognostic criteria permitted to improve significantly the results of social rehabilitation of patients, and also prophylactic measures directed to avert the disease recurrence were elucidated.

[Causes of post-gastrectomy and post-vagotomy recurrences of peptic ulcer].

The article gives an analysis of causes of recurrences of ulcer disease of the stomach and duodenum in 913 patients. The use of various methods of examination enabled the authors to make a conclusion that in spite of diversity of causes of recurrent ulcer disease it is necessary to clearly establish the prevailing action of one of the causes which will allow to determine correct volume of reoperations aimed at making the conditions of digestion in the upper parts of the gastro-intestinal tract close to physiological ones.

[Characteristics of emergency interventions in perforated and bleeding recurrent gastroduodenal ulcers].

The article presents an experience with the surgical treatment of 97 patients with recurrent ulcers of the stomach and duodenum complicated by bleedings and perforations. The specific feature is that the patients were at the hospital at the moment when the complications appeared. Strict indications for certain kinds of operations allowed to decrease lethality to 5.