Real-time membrane puncture detection using force sensors for micro-injections in phantoms

Micro-manipulators provide tools for researchers to improve workflow in common preclinical and clinical applications. Following drug delivery injections where drugs did not reach their target will squander research time, experimental animals and other resources. An ultrasound-guided robot developed at Robarts Research Institute was revised to implement closed-loop force feedback to compensate for tissue deformation during micro-interventions. Force sensors can detect puncture events as the needle penetrates tissue membranes, thereby reducing damage to surrounding tissues by preventing the needle from overshooting its target. Changing the angle of injection determined that the range of detectable forces during injections into tissue-mimicking phantoms suggests that sensors accurately measure projection of the needle force onto the vertical direction and are sensitive to puncture events through relatively thick (0.15 mm) membranes. Injections into mouse tissue yielded low success rates, suggesting different experimental designs are necessary to provide safer and less traumatic procedures, thus accelerating preclinical research

Educational trails of the Racławka Valley Nature Reserve and their potential for geoeducation

The Racławka Valley is located west of Krakow, in the Krakow-Częstochowa Upland. This is a place of high bio- and geodiversity, where various rocks of different ages outcrop in vast excavation pits, narrow gorges or form characteristic monadnocks. The richness of various morphological forms and special habitats led to the constitution of a nature reserve, covering most of the Racławka Valley and adjacent, southern parts of the Szklarka Valley. Three educational trails lead through the reserve, connecting a number of geosites. The Geotourism Students’ Scientific Club (GSSC) from AGH University of Science and Technology examined the usability of these trails for geoeducation. After completing geotourism valorisation, adequate teaching materials were prepared, and different age groups were guided around the trails. Their comprehension has been verified by quizzes and opinions gathered through questionnaires. On the bases of these, the three educational trails were widely described and assessed in respect for their terrain difficulty, accessibility, and infrastructure. Each trail has a leitmotif and a specific theme, however geosites from different trails can be combined together to get a route of a chosen theme. The GSSC also released three new geotourism guidebooks, one for each trail, as a result of AGH rector's grant projects in the years 2018–2020.Dolina Racławki położona jest na zachód od Krakowa, na Wyżynie Krakowsko-Częstochowskiej. Stanowi ona obszar o dużejbio- i georóżnorodności, gdzie rozmaite skały o różnym wieku odsłaniają się w rozległych wyrobiskach, na ścianach wąwozów lub w postaci ostańców. Ze względu na bogactwo form morfologicznych i wykształcone na nich siedliska, większość doliny Racławkii przyległą, południową część doliny Szklarki objęto rezerwatem przyrody. Przez obszar rezerwatu prowadzą trzy ścieżki dydaktyczne łączące szereg geostanowisk. Koło Naukowe Geoturystyka (KNGt) z Akademii Górniczo-Hutniczej zbadało ich przydatność dla geoedukacji. Po dokonaniu waloryzacji geoturystycznej opracowano materiały dydaktyczne, a następnie po ścieżkach oprowadzono różne grupy wiekowe. Za pomocą quizów sprawdzono zrozumienie przez uczestników omawianych tematów, a opinie zebrano w formie ankiet. Działania te umożliwiły dokładne opisanie ścieżek oraz ich ocenę pod kątem trudności terenu, dostępnościi infrastruktury. Każda ze ścieżek ma motyw przewodni, można je jednak z powodzeniem łączyć, by zaplanować trasę o określonej tematyce. KNGt przygotowało też trzy przewodniki geoturystyczne po dolinie Racławki, po jednym dla każdej ze ścieżek, w ramach Grantu Rektora AGH w latach 2018–2020

3D PET image reconstruction based on Maximum Likelihood Estimation Method (MLEM) algorithm

Positron emission tomographs (PET) do not measure an image directly. Instead, they measure at the boundary of the field-of-view (FOV) of PET tomograph a sinogram that consists of measurements of the sums of all the counts along the lines connecting two detectors. As there is a multitude of detectors build-in typical PET tomograph structure, there are many possible detector pairs that pertain to the measurement. The problem is how to turn this measurement into an image (this is called imaging). Decisive improvement in PET image quality was reached with the introduction of iterative reconstruction techniques. This stage was reached already twenty years ago (with the advent of new powerful computing processors). However, three dimensional (3D) imaging remains still a challenge. The purpose of the image reconstruction algorithm is to process this imperfect count data for a large number (many millions) of lines-of-responce (LOR) and millions of detected photons to produce an image showing the distribution of the labeled molecules in space.Comment: 10 pages, 7 figure

Plastic scintillators for positron emission tomography obtained by the bulk polymerization method

This paper describes three methods regarding the production of plastic scintillators. One method appears to be suitable for the manufacturing of plastic scintillator, revealing properties which fulfill the requirements of novel positron emission tomography scanners based on plastic scintillators. The key parameters of the manufacturing process are determined and discussed.Comment: 7 pages, 4 figure

Application of the compress sensing theory for improvement of the TOF resolution in a novel J-PET instrument

Nowadays, in positron emission tomography (PET) systems, a time of fl ight (TOF) information is used to improve the image reconstruction process. In TOF-PET, fast detectors are able to measure the difference in the arrival time of the two gamma rays, with the precision enabling to shorten signifi cantly a range along the line-of-response (LOR) where the annihilation occurred. In the new concept, called J-PET scanner, gamma rays are detected in plastic scintillators. In a single strip of J-PET system, time values are obtained by probing signals in the amplitude domain. Owing to compressive sensing (CS) theory, information about the shape and amplitude of the signals is recovered. In this paper, we demonstrate that based on the acquired signals parameters, a better signal normalization may be provided in order to improve the TOF resolution. The procedure was tested using large sample of data registered by a dedicated detection setup enabling sampling of signals with 50-ps intervals. Experimental setup provided irradiation of a chosen position in the plastic scintillator strip with annihilation gamma quanta

Multiple scattering and accidental coincidences in the J-PET detector simulated using GATE package

Novel Positron Emission Tomography system, based on plastic scintillators, is developed by the J-PET collaboration. In order to optimize geometrical configuration of built device, advanced computer simulations are performed. Detailed study is presented of background given by accidental coincidences and multiple scattering of gamma quanta

A novel method based solely on field programmable gate array (FPGA) units enabling measurement of time and charge of analog signals in positron emission tomography (PET)

Abstract: This article presents an application of a novel technique for precise measurements of time and charge based solely on a field programmable gate array (FPGA) device for positron emission tomography (PET). The described approach simplifies electronic circuits, reduces the power consumption, lowers costs, merges front-end electronics with digital electronics, and also makes more compact final design. Furthermore, it allows to measure time when analog signals cross a reference voltage at different threshold levels with a very high precision of ~15 ps (rms) and thus enables sampling of signals in a voltage domain

Psychological resilience and job satisfaction and the effectiveness of social media marketing employees

The study aimed to verify the relationship between social media marketing employees\u27 mental resilience and satisfaction and their effectiveness at work in Poland, a post-transition economy. We assumed that higher mental stability and employee satisfaction would significantly affect employee effectiveness. The study used the psychological resilience scale (SPP-25), the job satisfaction scale, and the author\u27s questionnaire to measure employee effectiveness. We conducted a case study and analyzed data from 51 respondents from three Polish marketing companies dealing with social media. Our results suggest that mental resilience and satisfaction significantly correlate with employee effectiveness. We contribute to developing a new questionnaire to measure employee effectiveness and build a correlation model for management support in companies with social media activities, psychological resilience and job satisfaction, and the effectiveness of social media marketing employees

Ścieżki edukacyjne Rezerwatu Przyrody Dolina Racławki i ich potencjał geoedukacyjny

The Racławka Valley is located west of Krakow, in the Krakow-Częstochowa Upland. This is a place of high bio- and geodiver-sity, where various rocks of different ages outcrop in vast excavation pits, narrow gorges or form characteristic monadnocks. The richness of various morphological forms and special habitats led to the constitution of a nature reserve, covering most of the Racławka Valley and adjacent, southern parts of the Szklarka Valley. Three educational trails lead through the reserve, connecting a number of geosites. The Geotourism Students’ Scientific Club (GSSC) from AGH University of Science and Technology examined the usability of these trails for geoeducation. After completing geotourism valorisation, adequate teaching materials were prepared, and different age groups were guided around the trails. Their comprehension has been verified by quizzes and opinions gathered through questionnaires. On the bases of these, the three educational trails were widely described and assessed in respect for their terrain difficulty, accessibility, and infrastructure. Each trail has a leitmotif and a specific theme, however geosites from different trails can be combined together to get a route of a chosen theme. The GSSC also released three new geotourism guidebooks, one for each trail, as a result of AGH rector's grant projects in the years 2018–2020.Dolina Racławki położona jest na zachód od Krakowa, na Wyżynie Krakowsko-Częstochowskiej. Stanowi ona obszar o dużej bio- i georóżnorodności, gdzie rozmaite skały o różnym wieku odsłaniają się w rozległych wyrobiskach, na ścianach wąwozów lub w po-staci ostańców. Ze względu na bogactwo form morfologicznych i wykształcone na nich siedliska, większość doliny Racławki i przyległą, południową część doliny Szklarki objęto rezerwatem przyrody. Przez obszar rezerwatu prowadzą trzy ścieżki dydaktyczne łączące szereg geostanowisk. Koło Naukowe Geoturystyka (KNGt) z Akademii Górniczo-Hutniczej zbadało ich przydatność dla geoedukacji. Po dokona-niu waloryzacji geoturystycznej opracowano materiały dydaktyczne, a następnie po ścieżkach oprowadzono różne grupy wiekowe. Za po-mocą quizów sprawdzono zrozumienie przez uczestników omawianych tematów, a opinie zebrano w formie ankiet. Działania te umożliwiły dokładne opisanie ścieżek oraz ich ocenę pod kątem trudności terenu, dostępności i infrastruktury. Każda ze ścieżek ma motyw przewodni, można je jednak z powodzeniem łączyć, by zaplanować trasę o określonej tematyce. KNGt przygotowało też trzy przewodniki geoturystycz-ne po dolinie Racławki, po jednym dla każdej ze ścieżek, w ramach Grantu Rektora AGH w latach 2018–2020

Exploring virus release as a bottleneck for the spread of influenza A virus infection in vitro and the implications for antiviral therapy with neuraminidase inhibitors

<div><p>Mathematical models (MMs) have been used to study the kinetics of influenza A virus infections under antiviral therapy, and to characterize the efficacy of antivirals such as neuraminidase inhibitors (NAIs). NAIs prevent viral neuraminidase from cleaving sialic acid receptors that bind virus progeny to the surface of infected cells, thereby inhibiting their release, suppressing infection spread. When used to study treatment with NAIs, MMs represent viral release implicitly as part of viral replication. Consequently, NAIs in such MMs do not act specifically and exclusively on virus release. We compared a MM with an explicit representation of viral release (i.e., distinct from virus production) to a simple MM without explicit release, and investigated whether parameter estimation and the estimation of NAI efficacy were affected by the use of a simple MM. Since the release rate of influenza A virus is not well-known, a broad range of release rates were considered. If the virus release rate is greater than ∼0.1 h⁻¹, the simple MM provides accurate estimates of infection parameters, but underestimates NAI efficacy, which could lead to underdosing and the emergence of NAI resistance. In contrast, when release is slower than ∼0.1 h⁻¹, the simple MM accurately estimates NAI efficacy, but it can significantly overestimate the infectious lifespan (i.e., the time a cell remains infectious and producing free virus), and it will significantly underestimate the total virus yield and thus the likelihood of resistance emergence. We discuss the properties of, and a possible lower bound for, the influenza A virus release rate.</p></div