Cosmic-Ray Acceleration at Ultrarelativistic Shock Waves: Effects of Downstream Short-Wave Turbulence

The present paper is the last of a series studying the first-order Fermi acceleration processes at relativistic shock waves with the method of Monte Carlo simulations applied to shocks propagating in realistically modeled turbulent magnetic fields. The model of the background magnetic field structure of Niemiec & Ostrowski (2004, 2006) has been augmented here by a large-amplitude short-wave downstream component, imitating that generated by plasma instabilities at the shock front. Following Niemiec & Ostrowski (2006), we have considered ultrarelativistic shocks with the mean magnetic field oriented both oblique and parallel to the shock normal. For both cases simulations have been performed for different choices of magnetic field perturbations, represented by various wave power spectra within a wide wavevector range. The results show that the introduction of the short-wave component downstream of the shock is not sufficient to produce power-law particle spectra with the "universal" spectral index 4.2. On the contrary, concave spectra with cutoffs are preferentially formed, the curvature and cutoff energy being dependent on the properties of turbulence. Our results suggest that the electromagnetic emission observed from astrophysical sites with relativistic jets, e.g. AGN and GRBs, is likely generated by particles accelerated in processes other than the widely invoked first-order Fermi mechanism.Comment: 9 pages, 8 figures, submitted to Ap

Cosmic-ray Acceleration at Ultrarelativistic Shock Waves: Effects of a "Realistic" Magnetic Field Structure

First-order Fermi acceleration processes at ultrarelativistic shocks are studied with Monte Carlo simulations. The accelerated particle spectra are derived by integrating the exact particle trajectories in a turbulent magnetic field near the shock. ''Realistic'' features of the field structure are included. We show that the main acceleration process at superluminal shocks is the particle compression at the shock. Formation of energetic spectral tails is possible in a limited energy range only for highly perturbed magnetic fields, with cutoffs occuring at low energies within the resonance energy range considered. These spectral features result from the anisotropic character of particle transport in the downstream magnetic field, where field compression produces effectively 2D perturbations. Because of the downstream field compression, the acceleration process is inefficient in parallel shocks for larger turbulence amplitudes, and features observed in oblique shocks are recovered. For small-amplitude turbulence, wide-energy range particle spectra are formed and modifications of the process due to the existence of long-wave perturbations are observed. In both sub- and superluminal shocks, an increase of \gamma leads to steeper spectra with lower cut-off energies. The spectra obtained for the ``realistic'' background conditions assumed here do not converge to the ``universal'' spectral index claimed in the literature. Thus the role of the first-order Fermi process in astrophysical sources hosting relativistic shocks requires serious reanalysis.Comment: submitted to Ap

Fallowing of selected arable fields in a farmland mosaic affects processes on landscape level: a case study of small mammal communities

In 2008 on six 1-ha plots the structure and species diversity of small mammal community inhabiting a narrow belt of coastal zone of the Łuknajno Lake (Masurian Lake District, North-East of Poland) were studied. The results obtained were compared with the results of similar studies carried out in the same area in 1981, when still intensive agricultural activities were present around the lake (abandoned in 1991 by leaving the agricultural fields fallow). In comparison with 1981, a decrease in the number of species inhabiting the fringe of the lake was discovered, as well as some significant changes in the domination structure of the community. Currently, the dominant forest species - the bank vole Myodes glareolus (Schreber 1780) and the yellow-necked mouse Apodemus flavicollis (Melchior 1834) - replaced the most numerous in 1981 - the striped field mouse Apodemus agrarius (Pallas 1771). Taking into consideration the fact that environmental conditions at the coastal zone have not changed, it was suggested that the changes in the community of small mammals were caused by setting aside arable lands around the lake. The results obtained lead to the conclusion that the range of the ecological effects of local changes in the landscape mosaic may include an area much larger than the one directly affected by these changes. They constitute the basis for a discussion on the relationship between various elements of environmental mosaic in heterogeneous landscape

High normal blood pressure - clinical fact or myth?

W ostatniej dekadzie dyskutuje się nad klinicznym znaczeniem wysokich prawidłowych wartości ciśnienia tętniczego. Szacuje się, że rozpowszechnienie ciśnienia wysokiego prawidłowego może wynosić około 30% i wiąże się z większym niż ciśnienie optymalne ryzykiem sercowo-naczyniowym. Częściej również towarzyszą mu inne czynniki ryzyka rozwoju chorób układu sercowo-naczyniowego, w tym cechy typowe dla zespołu metabolicznego. Według obecnych zaleceń ESH-ESC wysokie prawidłowe ciśnienie tętnicze wymaga postępowania niefarmakologicznego, o ile nie współistnieje z chorobami nerek lub układu sercowo-naczyniowego. Obecnie brakuje przekonujących danych o konieczności terapii farmakologicznej osób z ciśnieniem wysokim prawidłowym obciążonych niskim ryzykiem sercowo-naczyniowym.During last decade, an increased interest in the clinical significance of high normal blood pressure has arisen. Its prevalence is estimated at around 30% and is associated with increased cardiovascular risk. Other cardiovascular risk factors, including metabolic syndrome, are also related to high normal blood pressure values. According to ESH/ /ESC guidelines, lifestyle modifications alone should be implemented in patients with high normal blood pressure, unless it coexists with renal or cardiovascular diseases. Current data regarding the necessity of pharmacotherapy in patients with high normal blood pressure and low cardiovascular risk are unconvincing

A Strong Neutrophil Elastase Proteolytic Fingerprint Marks the Carcinoma Tumor Proteome

Proteolytic cascades are deeply involved in critical stages of cancer progression. During the course of peptide-wise analysis of shotgun proteomic data sets representative of colon adenocarcinoma (AC) and ulcerative colitis (UC), we detected a cancer-specific proteolytic fingerprint com- posed of a set of numerous protein fragments cleaved C-terminally to V, I, A, T, or C residues, significantly over-represented in AC. A peptide set linked by a common VIATC cleavage consensus was the only prominent can- cer-specific proteolytic fingerprint detected. This se- quence consensus indicated neutrophil elastase as a source of the fingerprint. We also found that a large frac- tion of affected proteins are RNA processing proteins associated with the nuclear fraction and mostly cleaved within their functionally important RNA-binding domains. Thus, we detected a new class of cancer-specific pep- tides that are possible markers of tumor-infiltrating neu- trophil activity, which often correlates with the clinical outcome. Data are available via ProteomeXchange with identifiers: PXD005274 (Data set 1) and PXD004249 (Data set 2). Our results indicate the value of peptide-wise anal- ysis of large global proteomic analysis data sets as op- posed to protein-wise analysis, in which outlier differen- tial peptides are usually neglected

The diagnostic value of dual-phase SPECT/CT scintigraphy based on transport kinetics of 99mTc-sestamibi confirmed with histopathological findings in patients with secondary hyperparathyroidism — practical consideration

BACKGROUND: Dual phase 99mTc-sestamibi SPECT/CT preoperative parathyroid scintigraphy (PPS) is seldom discussedin terms of the transport kinetics of the tracer.Objectives: To assess the relationship between the characteristic type of tracer transport in particular PPS and histopathologicalfindings in patients with secondary hyperparathyroidism (sHPT).MATERIAL AND METHODS: The study comprised 27 patients (13 females and 14 males) with sHPT. Based on tracer accumulationin early phase (EP) and delayed phase (DP), the following types of accumulation for PPS(+) lesions were identified: EP(–)/DP(+) (type I), EP(+)/DP(+) (type II), EP(+)/DP(–) (type III). EP(–)/DP(–) (type IV) lesions constituted PPS(–) group invisible inSPECT/CT. Overall, 69 lesions 59 PPS(+) and 10 PPS(–) were evaluated histopathologically.RESULTS: Among SPECT/CT PPS(+), types I, II and III occurred in 9 (15%), 49 (83%), and 1 (2%) lesions, respectively. Thefrequency of histopathological diagnosis of normal and abnormal (APG — adenoma or hyperplasia) parathyroid gland, as wellas non-parathyroid (thyroid, lymph nodes, or fat) lesions differed significantly between type I, II, and III lesions (p = 0.036).APG histopathological diagnosis was significantly more frequent in lesions with type II uptake than in lesions with type I uptake(76% vs. 33%, p = 0.0197). Type II lesions had significantly higher odds for histopathological diagnosis of APG or NPG thantype IV, PPS(–) lesions [odds ratio = 13.1 (95% CI: 2.75 to 63.27)].CONCLUSIONS: For SHP patients evaluated with SPECT/CT PPS accumulation type I is a weak premise for surgeon to findparathyroid pathology. Only persistent 99mTc-sestamibi accumulation in both phases - equivocal with accumulation type II— effectively differentiates parathyroid and non-parathyroid lesions as well as indicates with high probability the presence ofadenoma or hyperplasia. Type III consistent with washout pattern is rare in sHPT

Professor Bolesław Rutkowski's 70th birthday : laudatio

On 5 December 2014 Professor Bolesław Rutkowski, the outstanding Polish nephrologist, doctor and researcher, renowned organizer, our teacher, colleague and friend, will celebrate his 70th birthday. We would like to take this opportunity to present to you his life and his scientific achievements

Semi-quantitative method for the assessment of focal lesions in parathyroid scintigraphy with relation to histopathology: a prospective study

BBACKGROUND: The aim of this paper was to analyse our own semi-quantitative method of assessing focal lesions localised in pre-operative diagnostic scintigraphy of primary hyperparathyroidism (PHPT) using 99mTc-MIBI with washout and comparing these data with the result of the histopathological examination (HP). MATERIAL AND METHODS: A total of 40 (37 female, 3 male, average age 58.7 years) patients with a suspicion of PHPT were enrolled for prospective analysis. Dual phase planar and SPECT/CT examination with 99mTc-MIBI were performed. The tumour to background ratios in the 10th and 120th minute were calculated (TBR10 and TBR120) on the basis of the planar acquisition. PTH, ionised calcium and phosphate levels were measured. Parathyroid surgery alone or combined with subtotal/total thyreoidectomy was conducted in 23 (57.5%) and 17 (42.5%) patients, respectively. A HP was performed in all patients. RESULTS: Average concentration of PTH in the whole group was 243.95 pg/ml. There was a statistically significant correlation between medians of PTH concentration and parathyroid histopathological results (p = 0.01). A total of 45 lesions of increased uptake were found in 32 (80.0%) and 34 (85%) patients in the early phase and the delayed phase, respectively. The post-operative material contained 20 (44.5%) parathyroid adenomas, 11 (24.5%) cases of hyperplasia, 2 (4.4%) cancers, 4 (8.9%) cases of normal parathyroid tissue, 2 (4.4%) lymph nodes and 6 (13.3%) cases of thyroid gland tissue. The medians of TBR10 and TBR120 for lesions examined in the HP were respectively: 3.64 and 2.59 for adenoma; 3.08 and 2.18 for hyperplasia; 7.7 and 5.5 for parathyroid cancer, 4.89 and 3.16 for normal tissue and 5.26 and 2.95 for lymph nodes or thyroid gland tissue. A high correlation coefficient of TBR10 to TBR120 in the parathyroid adenoma and parathyroid hyperplasia groups was observed with r = 0.867 and r = 0.964, respectively. The ρr correlation coefficient of TBR10 to TBR120 for normal parathyroid was 0.4. There was a statistically significant association between the HP and TBR10 medians (p = 0.047), but not between histopathology and TBR120 medians (p = 0.840). CONCLUSIONS: The washout technique in pre-operative 99mTc-MIBI scintigraphy is effective in detecting lesions of the parathyroid (cancer, adenoma, hyperplasia, normal tissue of the parathyroid). Parathyroid cancers in semi-quantitative analysis were characterised by a slightly higher TBR. However, it is impossible to differentiate lesions based on this data. Histopathology results are significantly associated with TBR and PTH