Long-Time Tails and Anomalous Slowing Down in the Relaxation of Spatially Inhomogeneous Excitations in Quantum Spin Chains

Exact analytic calculations in spin-1/2 XY chains, show the presence of long-time tails in the asymptotic dynamics of spatially inhomogeneous excitations. The decay of inhomogeneities, for $t\to \infty$, is given in the form of a power law $$(t/\tau_{Q}) ^{-\nu_{Q}}$$ where the relaxation time $\tau_{Q}$ and the exponent $\nu_{Q}$ depend on the wave vector $Q$, characterizing the spatial modulation of the initial excitation. We consider several variants of the XY model (dimerized, with staggered magnetic field, with bond alternation, and with isotropic and uniform interactions), that are grouped into two families, whether the energy spectrum has a gap or not. Once the initial condition is given, the non-equilibrium problem for the magnetization is solved in closed form, without any other assumption. The long-time behavior for $t\to \infty$ can be obtained systematically in a form of an asymptotic series through the stationary phase method. We found that gapped models show critical behavior with respect to $Q$, in the sense that there exist critical values $Q_{c}$, where the relaxation time $\tau_{Q}$ diverges and the exponent $\nu_{Q}$ changes discontinuously. At those points, a slowing down of the relaxation process is induced, similarly to phenomena occurring near phase transitions. Long-lived excitations are identified as incommensurate spin density waves that emerge in systems undergoing the Peierls transition. In contrast, gapless models do not present the above anomalies as a function of the wave vector $Q$.Comment: 25 pages, 2 postscript figures. Manuscript submitted to Physical Review

Exact diagonalization of the generalized supersymmetric t-J model with boundaries

We study the generalized supersymmetric $t-J$ model with boundaries in three different gradings: FFB, BFF and FBF. Starting from the trigonometric R-matrix, and in the framework of the graded quantum inverse scattering method (QISM), we solve the eigenvalue problems for the supersymmetric $t-J$ model. A detailed calculations are presented to obtain the eigenvalues and Bethe ansatz equations of the supersymmetric $t-J$ model with boundaries in three different backgrounds.Comment: Latex file, 32 page

Effect of genetic variation in CYP450 on Gonadal impairment in a European cohort of female childhood cancer survivors, based on a candidate gene approach: Results from the pancareLIFE study

Background: Female childhood cancer survivors (CCSs) carry a risk of therapy-related gonadal dysfunction. Alkylating agents (AA) are well-established risk factors, yet inter-individual variability in ovarian function is observed. Polymorphisms in CYP450 enzymes may explain this variability in AA-induced ovarian damage. We aimed to evaluate associations between previously identified genetic polymorphisms in CYP450 enzymes and AA-related ovarian function among adult CCSs. Methods: Anti-Müllerian hormone (AMH) levels served as a proxy for ovarian function in a discovery cohort of adult female CCSs, from the pan-European PanCareLIFE cohort (n = 743; age (years): Median 25.8, interquartile range (IQR) 22.1-30.6). Using two additive genetic models in linear and logistic regression, nine genetic variants in three CYP450 enzymes were analyzed in relation to cyclophosphamide equivalent dose (CED) score and their impact on AMH levels. The main model evaluated the effect of the variant on AMH and the interaction model evaluated the modifying effect of the variant on the impact of CED score on log-transformed AMH levels. Results were validated, and meta-analysis performed, using the USA-based St. Jude Lifetime Cohort (n = 391; age (years): Median 31.3, IQR 26.6-37.4). Results: CYP3A4*3 was significantly associated with AMH levels in the discovery and replication cohort. Meta-analysis revealed a significant main deleterious effect (Beta (95% CI): −0.706 (−1.11-−0.298), p-value = 7 × 10−4) of CYP3A4*3 (rs4986910) on log-transformed AMH levels. CYP2B6*2 (rs8192709) showed a significant protective interaction effect (Beta (95% CI): 0.527 (0.126-0.928), p-value = 0.01) on log-transformed AMH levels in CCSs receiving more than 8000 mg/m2 CED. Conclusions: Female CCSs CYP3A4*3 carriers had significantly lower AMH levels, and CYP2B6*2 may have a protective effect on AMH levels. Identification of risk-contributing variants may improve individualized counselling regarding the treatment-related risk of infertility and fertility preservation options.Pattern Recognition and Bioinformatic

Caracterização bioquímica de soros de bezerros utilizados na manutenção de culturas celulares usadas em virologia Biochemical characterization of calf sera used for the growth of cell cultures used in virology

Oito lotes de soros de bezerros com idade maior ou menor de seis meses, usados para suplementar meios de cultivo de linhagens de células de uso difundido em virologia, foram testados quanto à sua capacidade promotora de crescimento (CPC) e classificados como bons promotores ou promotores pobres. Foram pesquisados parâmetros relacionados com macronutrientes para estabelecer o perfil bioquímico daqueles lotes. Os resultados obtidos podem ser considerados valores normais para animais aparentemente sadios. As variações que ocorreram para um mesmo parâmetro bioquímico, entre os resultados da pesquisa e os de alguns estudos existentes na literatura, podem ser atribuídas à metodologia utilizada, à raça e idade dos animais, ou mesmo à própria dieta regional. A análise estatística, realizada pela aplicação do teste "t" de Student aos valores das médias e dos desvios padrão, demonstrou que, com relação às frações séricas, não ocorreram diferenças significantes entre soros de CPC celular boa ou pobre, considerando-se t c=2,45, enquanto que, para soros animais maiores ou menores de seis meses, apenas os resultados relativos às frações alfa e beta (t=2,68 e 2,61, respectivamente) apresentaram significância, sendo superiores ao t crítico. Ficou evidenciado que a avaliação do conjunto de parâmetros bioquímicos pesquisados não permite diferenciar soros pertencentes aos dois grupos de animais, isto é, identificar soros de boa ou de pobre CPC, ou soros de bezerros maiores ou menores de seis meses de idade<br>Eight lots of the calf sera employed to supplement culture media for the cultivation of animal cells, of widespread use in virology obtained from calves above and below six months of age were rated as good or as poor cell growth promoters according to their growth promoting capacity (GPC). Parameters related to macronutrients contained in these serum lots were then evaluated with the purpose of establishing their biochemical profiles. The results obtained can be considered as normal values for apparently healthy animal donors. Fluctuations found between the data of this investigation and those mentioned in the literature for certain biochemical parameters are probably due to the methodology employed, the breed and age of the animals, or even to regional diet. Student's "t" test was applied for the statistical analysis of the results and demonstrated that, as far as serum fractions were concerned, no significant differences occurred between sera rated as good and poor cell growth promoters, taking t c= 2.45. For calf sera from animals above and below six months of age, two tests relating to alfa and beta fractions were significant (t=2.68 and 2.61 respectively). It was demonstrated that the evaluation of the biochemical parameters mentioned "per se" neither leads to the identification of calf sera presentig good or poor GPC, nor of sera harvested from calves younger or older than six months

Effect of genetic variation in CYP450 on Gonadal impairment in a European cohort of female childhood cancer survivors, based on a candidate gene approach

Background: Female childhood cancer survivors (CCSs) carry a risk of therapy-related gonadal dysfunction. Alkylating agents (AA) are well-established risk factors, yet inter-individual variability in ovarian function is observed. Polymorphisms in CYP450 enzymes may explain this variability in AA-induced ovarian damage. We aimed to evaluate associations between previously identified genetic polymorphisms in CYP450 enzymes and AA-related ovarian function among adult CCSs. Methods: Anti-Müllerian hormone (AMH) levels served as a proxy for ovarian function in a discovery cohort of adult female CCSs, from the pan-European PanCareLIFE cohort (n = 743; age (years): Median 25.8, interquartile range (IQR) 22.1-30.6). Using two additive genetic models in linear and logistic regression, nine genetic variants in three CYP450 enzymes were analyzed in relation to cyclophosphamide equivalent dose (CED) score and their impact on AMH levels. The main model evaluated the effect of the variant on AMH and the interaction model evaluated the modifying effect of the variant on the impact of CED score on log-transformed AMH levels. Results were validated, and meta-analysis performed, using the USA-based St. Jude Lifetime Cohort (n = 391; age (years): Median 31.3, IQR 26.6-37.4). Results: CYP3A4*3 was significantly associated with AMH levels in the discovery and replication cohort. Meta-analysis revealed a significant main deleterious effect (Beta (95% CI): −0.706 (−1.

Effect of Early Surgery vs Endoscopy-First Approach on Pain in Patients With Chronic Pancreatitis The ESCAPE Randomized Clinical Trial

IMPORTANCE For patients with painful chronic pancreatitis, surgical treatment is postponed until medical and endoscopic treatment have failed. Observational studies have suggested that earlier surgery could mitigate disease progression, providing better pain control and preserving pancreatic function.OBJECTIVE To determine whether early surgery is more effective than the endoscopy-first approach in terms of clinical outcomes.DESIGN, SETTING, AND PARTICIPANTS The ESCAPE trial was an unblinded, multicenter, randomized clinical superiority trial involving 30 Dutch hospitals participating in the Dutch Pancreatitis Study Group. From April 2011 until September 2016, a total of 88 patients with chronic pancreatitis, a dilated main pancreatic duct, and who only recently started using prescribed opioids for severe pain (strong opioids for <= 2 months or weak opioids for <= 6 months) were included. The 18-month follow-up period ended in March 2018.INTERVENTIONS There were 44 patients randomized to the early surgery group who underwent pancreatic drainage surgery within 6 weeks after randomization and 44 patients randomized to the endoscopy-first approach group who underwent medical treatment, endoscopy including lithotripsy if needed, and surgery if needed.MAIN OUTCOMES AND MEASURES The primary outcome was pain, measured on the Izbicki pain score and integrated over 18 months (range, 0-100 [increasing score indicates more pain severity]). Secondary outcomes were pain relief at the end of follow-up; number of interventions, complications, hospital admissions; pancreatic function; quality of life (measured on the 36-Item Short Form Health Survey [SF-36]); and mortality.RESULTS Among 88 patients who were randomized (mean age, 52 years; 21 (24%) women), 85 (97%) completed the trial. During 18 months of follow-up, patients in the early surgery group had a lower Izbicki pain score than patients in the group randomized to receive the endoscopy-first approach group (37 vs 49; between-group difference, -12 points [95% CI, -22 to -2]; P = .02). Complete or partial pain relief at end of follow-up was achieved in 23 of 40 patients (58%) in the early surgery vs 16 of 41 (39%)in the endoscopy-first approach group (P = .10). The total number of interventions was lower in the early surgery group (median, 1 vs 3; P < .001). Treatment complications (27% vs 25%), mortality (0% vs 0%), hospital admissions, pancreatic function, and quality of life were not significantly different between early surgery and the endoscopy-first approach.CONCLUSIONS AND RELEVANCE Among patients with chronic pancreatitis, early surgery compared with an endoscopy-first approach resulted in lower pain scores when integrated over 18 months. However, further research is needed to assess persistence of differences over time and to replicate the study findings.Transplant surger