High-Resolution Low-Noise Polarization Imaging Sensor for Astronomical Applications

Polarization imaging is useful to the field of astronomy because the polarization state caused by reflections, scattering events, and magnetic fields can be used to infer properties such as shape and index of refraction about celestial bodies. This work presents a low-noise high-resolution polarization imaging sensor consisting of a CCD imager overlaid with a nanowire linear polarizer filter array of four different orientations: 0°, 45°, 90°, and 135°) matched to the pixel pitch. Fabrication details and experimental setup for characterization are discussed. The performance of the sensor is assessed over a range of polarization states, light intensities, wavelengths, and incident angles; a model for crosstalk is also presented

Palliative large bowel resections. Impact of the laparoscopic approach

INTRODUCTION: Nowadays colorectal cancer (CRC) incidence rate increases in the Western world. The lack of effective screening programs results in diagnosis of advanced cases in our country. Combination of hematogenic, peritoneal or systemic CRC dissemination with present or potential complications from local disease is not an exception. The decision for palliative resection is not easy and is a matter of balance be­tween potential risks of operative intervention and advances due to local tumour resection. Positive aspects of the laparoscopic approach are important in planning of these interventions. The aim of this study is to as­sess the indications for laparoscopic palliative large bowel resections in the literature available and to share our own experience.PATIENTS AND METHODS: During a two-year period, in the HPB and General Surgery Clinic, Acibadem City Clinic, Tokuda Hospital of Sofia, six laparoscopic palliative colon resections were performed. In the all cases, multiple liver metastases were diagnosed without possibility of liver resection. The early periopera­tive results were analyzed.RESULTS: Four left colon resections were performed with primary anastomosis due to high-level large bow­el obstruction and two right colectomies were done for primary tumour bleeding. Three patients were over 77 years old and presented with comorbidity. Average hospital stay was 5,6 days. No perioperative compli­cations were observed.CONCLUSION: Minimal surgical trauma, short recovery period and well-defined indications are important features in the process of planning of palliative large bowel resections in patients with disseminated CRC. The objective is to reduce risks of complications connected with primary tumour and to assure a good pa­tient`s quality of life. Scr Sci Med 2017; 49(3): 27-3

Serological and Molecular Detection of Coxiella Burnetii in Clinical Samples from Veterinarians and Cattle Farm Workers from Gabrovo Region, Bulgaria

Coxiella burnetii, which causes Q fever, is a highly infectious agent that is widespread around the world.  During the last decades, the number of cases reported in Bulgaria varied from year to year. The present study aimed to determine the frequency of C. burnetii infection using ELISA and conventional PCR among freelance veterinarians and cattle farm workers in Gabrovo province, Bulgaria. In the period April 2020 to June, 2021 a total of 154 blood samples of target group was tested in the National Reference Laboratory of Cell cultures, rickettsia and oncogenic viruses (NRL CCROV) at NCIPD - Sofia. Diagnosis of C. burnetii was performed by indirect enzyme-linked immunosorbent assay ELISA (anti-Coxiella burnetii ph. II IgG/IgM) and by end-point PCR technique (to detect the sodB gene region of C. burnetii). By indirect ELISA assay of the tested 154 clinical samples, anti-C. burnetii positive ph. II IgM antibodies were registered in 37% of samples. A relatively high percentage are affected in the active age between 50-60 years old. Anti-C. burnetii positive ph. II IgG antibodies were proven at 50% of tested samples. A positive PCR signal for C. burnetii DNA was obtained at 37/154 (20% of samples) and follows the above reported trend of acute infection of active age patients. Around 10% of tested samples were positive for three C. burnetii laboratory markers. We conclude that Q fever is endemic in Bulgaria. More research is necessary in different Bulgarian regions to set the human risk groups, to diagnose acute and chronic Q fever and to determine the economic impact of Q fever in the cattle industry. In the NRL CCROV was developed diagnostic scheme including complex methods to improve early laboratory diagnosis of C. burnetii, allowing taking proper treatment of suspected with Q fever patients

Mini Review: Q Fever (Coxiellosis): Epidemiology, Pathogenesis and Current Laboratory Diagnosis

Q fever is zooantroponozis with global distribution caused by the strictly intracellular bacterium Coxiella burnetii. Causative agent of Q fever is an obligate intracellular parasite, classified in the genus Coxiella, family Coxiellaceae, class Gammaproteobacteria. The importance of the disease was assessed both in terms of human health and the serious economic damage they cause on livestock. Clinical manifestation of Q fever in humans is characterized by a wide variety - from asymptomatic infection to a chronic disease that can be fatal. Several basic methods have been developed to detection of C. burnetii. PCR and C. burnetii genomic sequences in whole blood are a sensitive and safe method of detection, with >90% sensitivity. A four-fold or greater rise of (CF) antibody (phase 2) between the paired sera is also diagnostic approach. Sensitivity of a four-fold rise in titre has been estimated as 73% ÷78% and specificity has been estimated as 90%, respectively. EIA is method with highly sensitive and specific. EIA detect IgM and then IgG antibodies which develop to phase II antigens in 10 to 14 days from symptom onset. IFA tests are of particular value for confirmation of acute infection and for diagnosis of chronic infection with high sensitivity. The technique detected IgG, IgM and IgA immunoglobulin classes. Suitable specimens for C. burnetii detection are blood samples. Although scientific interest in Q fever has always existed, a number of facts concerning the unforeseen nature of the epidemic, various clinical manifestations both in humans and in animals, the opportunities for chronic and other features of infection remain unclear. For this reason, timely and highly sensitive laboratory diagnosis is crucial for the outcome of the disease and subsequent treatment and monitoring

Novel Approach for Identification of Basic and Effective Reproduction Numbers Illustrated with COVID-19

This paper presents a novel numerical technique for the identification of effective and basic reproduction numbers, Re and R0, for long-term epidemics, using an inverse problem approach. The method is based on the direct integration of the SIR (Susceptible–Infectious–Removed) system of ordinary differential equations and the least-squares method. Simulations were conducted using official COVID-19 data for the United States and Canada, and for the states of Georgia, Texas, and Louisiana, for a period of two years and ten months. The results demonstrate the applicability of the method in simulating the dynamics of the epidemic and reveal an interesting relationship between the number of currently infectious individuals and the effective reproduction number, which is a useful tool for predicting the epidemic dynamics. For all conducted experiments, the results show that the local maximum (and minimum) values of the time-dependent effective reproduction number occur approximately three weeks before the local maximum (and minimum) values of the number of currently infectious individuals. This work provides a novel and efficient approach for the identification of time-dependent epidemics parameters

Visualization 1: 260 frames-per-second 648x488 resolution division-of-focal-plane polarimeter with structural dynamics and tracking applications

Visualization 1 Originally published in Optics Express on 18 April 2016 (oe-24-8-8243

Visualization 2: 260 frames-per-second 648x488 resolution division-of-focal-plane polarimeter with structural dynamics and tracking applications

Visualization 2 Originally published in Optics Express on 18 April 2016 (oe-24-8-8243

A 4-Megapixel Cooled CCD Division of Focal Plane Polarimeter for Celestial Imaging

The field of astronomy relies on spectral and polarization imagery recorded across a wide range of spectra to make inferences about imaged objects from nearby and distant galaxies. One of the challenges in recording celestial polarization information is recording multiple images filtered with various polarization optics, such as linear polarization filters or retarders, and with low-noise, low-dark-current sensors. In this paper, we present a division of focal plane polarimeter that can operate at room temperature down to -20 °C. When the imaging sensor operates at -20 °C, the dark currents is reduced by two orders of magnitude, which improves the polarization extinction ratio by ~5-fold. Comprehensive optoelectronic tests are presented with data recorded with the polarimeter