195 research outputs found
Energetic particle acceleration in a 3D magnetic field reconnection model: a role of MHD turbulence
The role of MHD turbulence in the cosmic ray acceleration process in a volume
with a reconnecting magnetic field is studied by means of Monte Carlo
simulations. We performed modelling of proton acceleration with the 3D analytic
model of stationary reconnection of Craig et al. (1995) providing the
unperturbed background conditions. Perturbations of particle trajectories due
to a turbulent magnetic field component were simulated using small-amplitude
pitch-angle momentum scattering, enabling modelling of both small and large
amplitude turbulence in a wide wave vector range. Within the approach, no
second-order Fermi acceleration process is allowed. Comparison of the
acceleration process in models involving particle trajectory perturbations to
the unperturbed one reveals that the turbulence can substantially increase the
acceleration efficiency, enabling much higher final particle energies and flat
particle spectra.Comment: 6 pages, 6 figures, MNRAS - accepte
The image of the native land in the consciousness of the Polish minority in Southern Bucovina (Romania) and its role in sustaining a group identity
Life Threatening Complication during Treatment of Erysipelas due to Undiagnosed Ischemia of the Calf
Erysipelas is a
superficial skin infection due to streptococci
strains, which usually responds well to
conservative treatment. Coexisting undiagnosed
ischemia of the extremity may lead to severe
complications. 57-year-old man developed large,
circumflex ulceration of his right calf within
two weeks before the admission after three-month treatment of erysipelas. Computer
angiography showed chronic occlusion of the
superficial femoral artery and the above knee
popliteal artery. Rapid debridement of the wound
took control over the infection. Patient
required complex vascular procedure which
allowed to prepare the ulcer for meshed skin
grafts. Patient was discharged home on 64th
hospital day with completely healed
ulcer
The constructional solutions for absorption of vibration in special vehicles operated in terrain
The paper presents possibilities of usage of innovative constructions in special vehicles for absorbing of vibrations. The regular vehicles, as passenger cars, have many solutions of suspensions. Depending on purpose of the car it can be generally grouped for soft suspensions with destination for passenger, family cars and hard suspensions for sports cars. According to safety and comfort requirements there are constant research on compromise solution. Thus we have mechanically, hydraulically, pneumatically and mechatronic constructions of suspensions. For the passenger cars the project assumptions are much easier to reach. It is assumed that vehicle will be driven on paved the way with carrying load less than construction parameters. For the special vehicles such assumptions can’t be done. The vehicles can be used as off road on natural ground and very often with extra load. Thus the universal solutions for suspensions are not good enough. Taking into consideration that special vehicles mostly are constructed basing on regular frame and truck chassis the possible solutions become very narrow. Thus the paper presents an approach with intermediate frame. The analysis presented are just small part of work packages of research programme Demonstrator + Supporting scientific research and development works in demonstration scale, the title of the project is Develop High Mobility Wheeled Platform for special applications (no. WND-DEM-1-325/00 KoPlatWysMob)
Technical elements for minimising of vibration effects in special vehicles
The paper presents chosen solutions and technical elements for minimising of vibration effects in special vehicles. Due to volume and scope of the impact, forces and load generated in special vehicle during operating these elements are extremely important for isolation and absorbing of vibration affecting human or load. As the example of such solutions frame, suspension of car-body and cabin adopt in high mobility wheeled platform were described
Critical limb ischemia caused by adductor canal compression syndrome — case report with the review of the literature
We report a case of a 55-year-old male who was diagnosed with the adductor canal compression syndrome– a rarely described nontraumatic disorder of the lower limb resulting from the external compression of thesuperficial femoral artery in the adductor canal, that may present with the symptoms ranging from intermittentexercise-induced claudication up to arterial obstruction and critical limb ischemia
Wideotorakoskopowa lobektomia mankietowa
Lobektomia mankietowa pozwala uniknąć rozległych resekcji, takich jak pneumonektomia, w sytuacjach występowania guza w centralnej części płuca. Najnowsze osiągnięcia techniki umożliwiają wykonywanie skomplikowanych zabiegów chirurgicznych typu wideotorakoskopowej lobektomii mankietowej (VABSL). W artykule przedstawiono przypadek 64-letniego pacjenta, u którego wykonano zabieg VABSL płata górnego prawego z powodu raka gruczołowego. Ze względu na umiejscowienie guza, podczas resekcji przecięto oskrzele i usunięto zmianę. Wynik badania wycinka pobranego w trakcie operacji nie ujawnił nacieku nowotworowego w linii cięcia oskrzela. Z powodu sztywnej zmiany uniemożliwiającej zszycie bez skręcenia, przeprowadzono lobektomię mankietową. Oskrzele nacięto poprzez cięcie robocze, częściowo pod kontrolą wzroku. Na całej linii przeprowadzono zespolenie za pomocą imadła do igieł do zabiegów otwartych, kleszczy i ciągłego szwu Maxon 4–0. Nie obserwowano powikłań w okresie pooperacyjnym, a kontrolna bronchoskopia wykazała szerokie światło w miejscu zespolenia.Lobektomia mankietowa pozwala uniknąć rozległych resekcji, takich jak pneumonektomia, w sytuacjach występowania guza w centralnej części płuca. Najnowsze osiągnięcia techniki umożliwiają wykonywanie skomplikowanych zabiegów chirurgicznych typu wideotorakoskopowej lobektomii mankietowej (VABSL). W artykule przedstawiono przypadek 64-letniego pacjenta, u którego wykonano zabieg VABSL płata górnego prawego z powodu raka gruczołowego. Ze względu na umiejscowienie guza, podczas resekcji przecięto oskrzele i usunięto zmianę. Wynik badania wycinka pobranego w trakcie operacji nie ujawnił nacieku nowotworowego w linii cięcia oskrzela. Z powodu sztywnej zmiany uniemożliwiającej zszycie bez skręcenia, przeprowadzono lobektomię mankietową. Oskrzele nacięto poprzez cięcie robocze, częściowo pod kontrolą wzroku. Na całej linii przeprowadzono zespolenie za pomocą imadła do igieł do zabiegów otwartych, kleszczy i ciągłego szwu Maxon 4–0. Nie obserwowano powikłań w okresie pooperacyjnym, a kontrolna bronchoskopia wykazała szerokie światło w miejscu zespolenia
Biogenic silver nanoparticles: assessment of their cytotoxicity, genotoxicity and study of capping proteins
The development of nanotechnology in the last two decades has led to the use of silver
nanoparticles (AgNPs) in various biomedical applications, including antimicrobial, anti-inflammatory,
and anticancer therapies. However, the potential of the medical application of AgNPs depends on
the safety of their use. In this work, we assessed the in vitro cytotoxicity and genotoxicity of silver
nanoparticles and identified biomolecules covering AgNPs synthesized from actinobacterial strain
SH11. The cytotoxicity of AgNPs against MCF-7 human breast cancer cell line and murine macrophage
cell line RAW 264.7 was studied by MTT assay, cell LDH (lactate dehydrogenase) release, and the
measurement of ROS (reactive oxygen species) level while genotoxicity in Salmonella typhimurium
cells was testing using the Ames test. The in vitro analysis showed that the tested nanoparticles
demonstrated dose-dependent cytotoxicity against RAW264.6 macrophages and MCF-7 breast cancer
cells. Moreover, biosynthesizedAgNPsdid not show a mutagenic e ect of S. typhimurium. The analyses
and identification of biomolecules present on the surface of silver nanoparticles showed that they were
associated with proteins. The SDS-PAGE (sodium dodecyl sulfate–polyacrylamide gel electrophoresis)
analysis revealed the presence of 34 and 43 kDa protein bands. The identification of proteins performed
by using LC-MS/MS (liquid chromatography with tandem mass spectrometry) demonstrated their
highest homology to bacterial porins. Capping biomolecules of natural origin may be involved in the
synthesis process of AgNPs or may be responsible for their stabilization. Moreover, the presence of
natural proteins on the surface of bionanoparticles eliminates the postproduction steps of capping
which is necessary for chemical synthesis to obtain the stable nanostructures required for application
in medicine
Severe calcification of forgotten Double-J ureteral stent in a patient with undiagnosed hyperparathyroidism
Background
Double J stent (DJ) is widely used in urological practice in patients with renal stones. However, its application is related to the risk of incrustation. We present a case of severe calcification of forgotten DJ in a patient with previously undiagnosed hyperparathyroidism (HPT).
Case presentation
A 30-year-old female was admitted to the Urology Department with renal colic. An initial kidney, ureter, and bladder X-ray revealed a completely calcified DJ catheter placed twelve months earlier. Unfortunately, the patient did not show up for a follow-up visit, and stent removal was not performed. Due to the extent of the disease, the patient was qualified for multistage endoscopic treatment. Total treatment lasted six months and consisted of five urereroscopies and one hybrid procedure. Simultaneously, diagnostics of a metabolic cause of the advanced stone disease suggested primary hyperparathyroidism, confirmed during parathyroid scintigraphy. After urological treatment had been completed, parathyroidectomy was performed. During a further 7-year follow-up, only one episode of renal colic occurred within the first year after treatment. The patient is stone-free until the present day.
Conclusions
Stents are designed to last usually up to six months, but they should be removed as quickly as possible after finishing treatment. Also, other causes such as a metabolic or hormonal imbalance should be considered. In our patient combination of forgotten DJ and HPT was the reason for excessive stone formation. Selective removal of the parathyroid gland was effective in the presented patient, with no stone recurrence observed
Structural studies and selected physical investigations of LiCoO2 obtained by combustion synthesis
Nanocrystalline powders of LiCoO2 were synthesized using a modified solution combustion method, and the effects of the annealing temperature (450-900 degrees C) on structure and composition were investigated using various methods, including XRD, SEM, EPR, and electrical studies. It was found that, as the process temperature increases, the value of the specific surface area decreases, and, hence, the size of the crystallites increases. XRD analysis showed that phase-pure LiCoO2 material was maintained without ad-ditional phases. EPR studies revealed the presence of two Ni3+ complexes resulting from Ni impurities. The electrical properties of the studied LiCoO2 samples were investigated by using impedance spectroscopy. Comparison of the effect of annealing tempera-ture on electrical conductivity shows a very interesting behavior. As the annealing temperature increases, the DC conductivity value increases, reaching a maximum at a temperature of 500 degrees C. However, further increase in the annealing temperature causes a steady decrease in the DC conductivity.Web of Science131482147
- …