The linear perturbation renormalization group (LPRG) is used to study the phase transition of the weakly coupled Ising chains with intrachain (J) and interchain nearest-neighbor (J_{1}) and ...next-nearest-neighbor (J_{2}) interactions forming the triangular and rectangular lattices in a field. The phase diagrams with the frustration point at J_{2}=-J_{1}/2 for a rectangular lattice and J_{2}=-J_{1} for a triangular lattice have been found. The LPRG calculations support the idea that the phase transition is always continuous except for the frustration point and is accompanied by a divergence of the specific heat. For the antiferromagnetic chains, the external field does not change substantially the shape of the phase diagram. The critical temperature is suppressed to zero according to the power law when approaching the frustration point with an exponent dependent on the value of the field.
The linear perturbation group transformation (LPRG) is used to study the thermodynamics of the axial next-nearest-neighbor Ising model with four spin interactions (extended ANNNI) in a field. The ...LPRG for weakly interacting Ising chains is presented. The method is used to study finite field para-ferrimagnetic phase transitions observed in layered uranium compounds, UAs1-xSex, UPd2Si2 or UNi2Si2. The above-mentioned systems are made of ferromagnetic layers and the spins from the nearest-neighbor and next-nearest-neighbor layers are coupled by the antiferromagnetic interactions J1<0 and J2<0, respectively. Each of these systems exhibits a triple point in which two ordered phases (ferrimagnetic and incommensurate) meet the paramagnetic one, and all undergo the high field phase transition from para- to ferrimagnetic (++-) phase. However, if in UAs1-xSex the para-ferri phase transition is of the first order as expected from the symmetry reason, in UT2Si2 (T=Pd, Ni) this transition seems to be a continuous one, at least in the vicinity of the multicritical point. Within the MFA, the critical character of the finite field para-ferrimagnetic transition at least at one isolated point can be described by the ANNNI model supplemented by an additional, e.g., four-spin interaction. However, in LPRG approximation for the ratio κ = J2/J1 around 0.5 there is a critical value of the field for which an isolated critical point also exists in the original ANNNI model. The positive four-spin interaction shifts the critical point towards higher fields and changes the shape of the specific heat curve. In the latter case for the fields small enough, the specific heat exhibits two-peak structure in the paramagnetic phase.
Objective
Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV) are rare small to medium-size vessel systemic diseases. As their clinical picture, organ involvement, and factors ...influencing outcome may differ between countries and geographical areas, we decided to describe a large cohort of Polish AAV patients coming from several referral centers—members of the Scientific Consortium of the Polish Vasculitis Registry (POLVAS).
Methods
We conducted a systematic multicenter retrospective study of adult patients diagnosed with AAV between Jan 1990 and Dec 2016 to analyze their clinical picture, organ involvement, and factors influencing outcome. Patients were enrolled to the study by nine centers (14 clinical wards) from seven Voivodeships populated by 22.3 mln inhabitants (58.2% of the Polish population).
Results
Participating centers included 625 AAV patients into the registry. Their distribution was as follows: 417 patients (66.7%) with GPA, 106 (17.0%) with MPA, and 102 (16.3%) with EGPA. Male-to-female ratios were almost 1:1 for GPA (210/207) and MPA (54/52), but EGPA was twice more frequent among women (34/68). Clinical manifestations and organ involvement were analyzed by clinical phenotype. Their clinical manifestations seem very similar to other European countries, but interestingly, men with GPA appeared to follow a more severe course than the women. Fifty five patients died. In GPA, two variables were significantly associated with death: permanent renal replacement therapy (PRRT) and respiratory involvement (univariate analysis). In multivariate analysis, PRRT (OR = 5.3; 95% confidence interval (CI) = 2.3–12.2), respiratory involvement (OR = 3.2; 95% CI = 1.06–9.7), and, in addition, age > 65 (OR = 2.6; 95% CI = 1.05–6.6) were independently associated with death. In MPA, also three variables were observed to be independent predictors of death: PRRT (OR = 5.7; 95% CI = 1.3–25.5), skin involvement (OR = 4.4; 95% CI = 1.02–19.6), and age > 65 (OR = 6.3; 95% CI = 1.18–33.7).
Conclusions
In this first multicenter retrospective study of the Polish AAV patients, we have shown that their demographic characteristics, disease manifestations, and predictors of fatal outcome follow the same pattern as those from other European countries, with men possibly suffering from more severe course of the disease.
Who is left, who is right? Sznajd-Weron, Katarzyna; Sznajd, Józef
Physica A,
06/2005, Letnik:
351, Številka:
2
Journal Article
Recenzirano
We propose a model to simulate the process of opinion formation in a society where the traditional division into leftists and rightists is not enough any longer. The model is based on the ...Ashkin–Teller idea to assign two Ising spins to each site (agent). The two states (up and down) of the first spin represent two possible opinions on any question in an economic area, and the two states of the second spin in a personal area. We assume that the mechanisms of opinion formation in both of these areas are different. The interaction between them is introduced in the form of a tolerance factor. It has been found, among others, that the formation of consensus between groups of agents which differ only in the economic area is quite simple, whereas if they differ in the personal area no consensus is possible.
Outcome assessment in large-vessel vasculitis (LVV) remains challenging and this impairs patient management and the conduct of clinical studies. Previous proposals for outcome tools have not included ...imaging. This study aimed to develop an imaging score to quantify damage in LVV and to assess the difference between Takayasu (TAK) and giant cell arteritis (GCA).
Ninety-six patients (41 TAK, 55 GCA) were identified from local registries at two University Hospitals in the UK. Radiologic lesions including stenosis, occlusion and aneurysm were evaluated in 25 arterial regions by enhanced computed tomography or magnetic resonance angiography. Lesion correlation with combined damage assessment scores was employed in a multiple regression analysis to define the weight of individual lesions and develop a damage index.
A numerical damage index was developed: the "Combined Arteritis Damage Score (CARDS)". The index was derived from a formula: number of regions with mild stenosis × 0.6 + number of regions with moderate to severe stenosis × 1.2 + number with occlusions × 1.6 + number with aneurysms × 0.8 in 25 arterial regions. The median CARDS was higher in TAK than GCA (4.1 and 0.6, interquartile range 1.3-5.7 and 0-3, p<0.001).
We have developed a damage assessment tool, CARDS, based on imaging in LVV of potential value to clinical studies and patient management. TAK and GCA differ in the radiologic severity of disease.
To evaluate the efficacy and safety of avacopan in the subgroup of patients with antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis receiving background induction therapy with ...rituximab in the phase 3 ADVOCATE trial.
Key efficacy outcomes were remission at week 26 and sustained remission at week 52. Additional outcomes included the Glucocorticoid Toxicity Index, estimated glomerular filtration rate, urinary albumin to creatinine ratio, health-related quality of life and safety.
Of the 330 patients who received study medication, 214 (64.8%) received rituximab (once weekly for 4 weeks), with a mean age of 59.8 years; 163 (76.2%) had renal vasculitis and 125 (58.4%) were newly diagnosed. Remission at week 26 and sustained remission at week 52 were achieved by 83/107 (77.6%) and 76/107 (71.0%) patients in the avacopan group and 81/107 (75.7%) and 60/107 (56.1%) in the prednisone taper group, respectively. The relapse rate, recovery of renal function, speed of reduction in albuminuria and glucocorticoid toxicity favoured the avacopan group. Serious adverse events occurred in 34.6% and 39.3% of patients in the avacopan and prednisone taper groups, respectively.
These data suggest that in patients with ANCA-associated vasculitis receiving rituximab, efficacy of treatment with avacopan compared with a prednisone taper was similar at week 26 and greater at week 52, with a favourable safety profile. In addition, avacopan was associated with improved renal outcomes and lower glucocorticoid toxicity. These results demonstrate the efficacy and safety of avacopan in patients receiving background induction therapy with rituximab.
NCT02994927.
The systemic vasculitides are a group of rare, chronic, relapsing, but often progressive inflammatory conditions. They are associated with a significant burden of morbidity both due to scarring from ...the disease itself and as a consequence of treatment with glucocorticoids and other potent immunosuppressive agents. Careful assessment of disease activity is critical to guide appropriate use of these potentially toxic therapies. It is also important to differentiate features of active disease from those attributable to damage, which will not respond to immunosuppression. As these are chronic complex conditions, the impact on a patient's functional ability and quality of life are also important considerations. Given the lack of a reliable biomarker for assessment of disease activity or damage in systemic vasculitis, clinical tools developed and validated for use initially in clinically trials are key outcome measures in the evaluation of these patients. While the conduct of randomised clinical trials in vasculitis has been significantly enhanced by the development and use of validated outcome measures, regular use of validated disease activity and damage measurements as part of routine care offers a structured approach, which can serve as the basis of justifying treatment decisions. The authors review the concepts of clinical assessment tools used in the evaluation of patients with systemic vasculitis in the setting of clinical practice, clinical trials and long term databases with particular emphasis on disease activity, damage, prognosis and function.
In the 330-patient ADVOCATE trial of avacopan for the treatment of antineutrophil cytoplasmic autoantibody (ANCA)-associated vasculitis, in which 81% of patients had renal involvement, estimated ...glomerular filtration rate (eGFR) increased on average 7.3 ml/min per 1.73 m2 in the avacopan group and 4.1 ml/min per 1.73 m2 in the prednisone group (P = 0.029) at week 52. This new analysis examines the results in the patient subgroup with severe renal insufficiency at enrollment into the trial, i.e., eGFR ≤20 ml/min per 1.73 m2.
eGFR was determined at baseline and over the course of the trial. Changes in eGFR were compared between the 2 treatment groups.
In ADVOCATE, 27 of 166 patients (16%) in the avacopan group and 23 of 164 patients (14%) in the prednisone group had a baseline eGFR ≤20 ml/min per 1.73 m2. At week 52, eGFR increased on average 16.1 and 7.7 ml/min per 1.73 m2 in the avacopan and prednisone groups, respectively (P = 0.003). The last eGFR value measured during the 52-week treatment period was ≥2-fold higher than baseline in 41% of patients in the avacopan group compared to 13% in the prednisone group (P = 0.030). More patients in the avacopan group versus prednisone group had increases in eGFR above 20, 30, and 45 ml/min per 1.73 m2, respectively. Serious adverse events occurred in 13 of 27 patients (48%) in the avacopan group and 16 of 23 patients (70%) in the prednisone group.
Among patients with baseline eGFR ≤20 ml/min per 1.73 m2 in the ADVOCATE trial, eGFR improved more in the avacopan group than in the prednisone group.
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