Dynamics of magnetization at infinite temperature in a Heisenberg spin chain

Understanding universal aspects of quantum dynamics is an unresolved problem in statistical mechanics. In particular, the spin dynamics of the one-dimensional Heisenberg model were conjectured as to belong to the Kardar-Parisi-Zhang (KPZ) universality class based on the scaling of the infinite-temperature spin-spin correlation function. In a chain of 46 superconducting qubits, we studied the probability distribution of the magnetization transferred across the chain's center, [Formula: see text]. The first two moments of [Formula: see text] show superdiffusive behavior, a hallmark of KPZ universality. However, the third and fourth moments ruled out the KPZ conjecture and allow for evaluating other theories. Our results highlight the importance of studying higher moments in determining dynamic universality classes and provide insights into universal behavior in quantum systems.

Stable quantum-correlated many-body states through engineered dissipation

Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for quantum simulation of high-temperature superconductivity or quantum magnetism. Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.

Comparative Effectiveness and Durability of Biologics in Clinical Practice: Month 12 Outcomes from the International, Observational Psoriasis Study of Health Outcomes (PSoHO)

INTRODUCTION

Given the chronic nature of psoriasis (PsO), more studies are needed that directly compare the effectiveness of different biologics over long observation periods. This study compares the effectiveness and durability through 12 months of anti-interleukin (IL)-17A biologics relative to other approved biologics in patients with moderate-to-severe psoriasis in a real-world setting.

METHODS

The Psoriasis Study of Health Outcomes (PSoHO) is an ongoing 3-year, prospective, non-interventional cohort study of 1981 adults with chronic moderate-to-severe plaque psoriasis initiating or switching to a new biologic. The study compares the effectiveness of anti-IL-17A biologics with other approved biologics and provides pairwise comparisons of seven individual biologics versus ixekizumab. The primary outcome was defined as the proportion of patients who had at least a 90% improvement in Psoriasis Area and Severity Index score (PASI90) and/or a score of 0 or 1 in static Physician Global Assessment (sPGA). Secondary objective comparisons included the proportion of patients who achieved PASI90, PASI100, a Dermatology Life Quality Index (DLQI) score of 0 or 1, and three different actions of durability of treatment response. Unadjusted response rates are presented alongside the primary analysis, which uses frequentist model averaging (FMA) to evaluate the adjusted comparative effectiveness.

RESULTS

Compared to the other biologics cohort, the anti-IL-17A cohort had a higher response rate (68.0% vs. 65.1%) and significantly higher odds of achieving the primary outcome at month 12. The two cohorts had similar response rates for PASI100 (40.5% and 37.1%) and PASI90 (53.9% and 51.7%) at month 12, with no significant differences between the cohorts in the adjusted analyses. At month 12, the response rates across the individual biologics were 53.5-72.6% for the primary outcome, 27.6-48.3% for PASI100, and 41.7-61.4% for PASI90.

CONCLUSIONS

These results show the comparative effectiveness of biologics at 6 and 12 months in the real-world setting.

TRIAL REGISTRATION

ClinicalTrials.gov identifier EUPAS24207.

Measurement-induced entanglement and teleportation on a noisy quantum processor

Measurement has a special role in quantum theory1: by collapsing the wavefunction, it can enable phenomena such as teleportation2 and thereby alter the 'arrow of time' that constrains unitary evolution. When integrated in many-body dynamics, measurements can lead to emergent patterns of quantum information in space-time3-10 that go beyond the established paradigms for characterizing phases, either in or out of equilibrium11-13. For present-day noisy intermediate-scale quantum (NISQ) processors14, the experimental realization of such physics can be problematic because of hardware limitations and the stochastic nature of quantum measurement. Here we address these experimental challenges and study measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping9,15-17 to avoid mid-circuit measurement and access different manifestations of the underlying phases, from entanglement scaling3,4 to measurement-induced teleportation18. We obtain finite-sized signatures of a phase transition with a decoding protocol that correlates the experimental measurement with classical simulation data. The phases display remarkably different sensitivity to noise, and we use this disparity to turn an inherent hardware limitation into a useful diagnostic. Our work demonstrates an approach to realizing measurement-induced physics at scales that are at the limits of current NISQ processors.

Speed of clinical improvement in the real-world setting from patient-reported Psoriasis Symptoms and Signs Diary: Secondary outcomes from the Psoriasis Study of Health Outcomes through 12 weeks

BACKGROUND

Rapid skin improvement is a key treatment goal of patients with moderate-to-severe psoriasis (PsO).

OBJECTIVES

To compare the speed of clinical improvement of approved biologics on the symptoms and signs of psoriasis assessed by patients using the validated Psoriasis Symptoms and Signs Diary (PSSD) through 12 weeks.

METHODS

Psoriasis Study of Health Outcomes (PSoHO) is an international, prospective, non-interventional study that compares the effectiveness of anti-interleukin (IL)-17A biologics versus other biologics, together with pairwise comparisons of ixekizumab versus five individual biologics in patients with PsO. Using the PSSD 7-day recall period, patients assessed the symptoms (itch, skin tightness, burning, stinging and pain) and signs (dryness, cracking, scaling, shedding/flaking, redness and bleeding) of their psoriasis (0-10). Symptom and sign summary scores (0-100) are derived from the average of individual scores. Percentage change in summary scores and proportion of patients with clinically meaningful improvements (CMI) in PSSD summary and individual scores are evaluated weekly. Longitudinal PSSD data are reported as observed with treatment comparisons analysed using mixed model for repeated measures (MMRM) and generalized linear mixed models (GLMM).

RESULTS

Across cohorts and treatments, eligible patients (n = 1654) had comparable baseline PSSD scores. From Week 1, the anti-IL-17A cohort achieved significantly larger score improvements in PSSD summary scores and a higher proportion of patients showed CMIs compared to the other biologics cohort through 12 weeks. Lower PSSD scores were associated with a greater proportion of patients reporting their psoriasis as no longer impacting their quality-of-life (DLQI 0,1) and a high level of clinical response (PASI100). Results also indicate a relationship between an early CMI in PSSD score at Week 2 and PASI100 score at Week 12.

CONCLUSIONS

Treatment with anti-IL-17A biologics, particularly ixekizumab, resulted in rapid and sustained patient-reported improvements in psoriasis symptoms and signs compared with other biologics in a real-world setting.

Non-Abelian braiding of graph vertices in a superconducting processor

Indistinguishability of particles is a fundamental principle of quantum mechanics¹. For all elementary and quasiparticles observed to date-including fermions, bosons and Abelian anyons-this principle guarantees that the braiding of identical particles leaves the system unchanged^2,3. However, in two spatial dimensions, an intriguing possibility exists: braiding of non-Abelian anyons causes rotations in a space of topologically degenerate wavefunctions^4-8. Hence, it can change the observables of the system without violating the principle of indistinguishability. Despite the well-developed mathematical description of non-Abelian anyons and numerous theoretical proposals^9-22, the experimental observation of their exchange statistics has remained elusive for decades. Controllable many-body quantum states generated on quantum processors offer another path for exploring these fundamental phenomena. Whereas efforts on conventional solid-state platforms typically involve Hamiltonian dynamics of quasiparticles, superconducting quantum processors allow for directly manipulating the many-body wavefunction by means of unitary gates. Building on predictions that stabilizer codes can host projective non-Abelian Ising anyons^9,10, we implement a generalized stabilizer code and unitary protocol²³ to create and braid them. This allows us to experimentally verify the fusion rules of the anyons and braid them to realize their statistics. We then study the prospect of using the anyons for quantum computation and use braiding to create an entangled state of anyons encoding three logical qubits. Our work provides new insights about non-Abelian braiding and, through the future inclusion of error correction to achieve topological protection, could open a path towards fault-tolerant quantum computing.

Formation of robust bound states of interacting microwave photons

Systems of correlated particles appear in many fields of modern science and represent some of the most intractable computational problems in nature. The computational challenge in these systems arises when interactions become comparable to other energy scales, which makes the state of each particle depend on all other particles1. The lack of general solutions for the three-body problem and acceptable theory for strongly correlated electrons shows that our understanding of correlated systems fades when the particle number or the interaction strength increases. One of the hallmarks of interacting systems is the formation of multiparticle bound states2-9. Here we develop a high-fidelity parameterizable fSim gate and implement the periodic quantum circuit of the spin-½ XXZ model in a ring of 24 superconducting qubits. We study the propagation of these excitations and observe their bound nature for up to five photons. We devise a phase-sensitive method for constructing the few-body spectrum of the bound states and extract their pseudo-charge by introducing a synthetic flux. By introducing interactions between the ring and additional qubits, we observe an unexpected resilience of the bound states to integrability breaking. This finding goes against the idea that bound states in non-integrable systems are unstable when their energies overlap with the continuum spectrum. Our work provides experimental evidence for bound states of interacting photons and discovers their stability beyond the integrability limit.

Noise-resilient edge modes on a chain of superconducting qubits

Inherent symmetry of a quantum system may protect its otherwise fragile states. Leveraging such protection requires testing its robustness against uncontrolled environmental interactions. Using 47 superconducting qubits, we implement the one-dimensional kicked Ising model, which exhibits nonlocal Majorana edge modes (MEMs) with ℤ 2 parity symmetry. We find that any multiqubit Pauli operator overlapping with the MEMs exhibits a uniform late-time decay rate comparable to single-qubit relaxation rates, irrespective of its size or composition. This characteristic allows us to accurately reconstruct the exponentially localized spatial profiles of the MEMs. Furthermore, the MEMs are found to be resilient against certain symmetry-breaking noise owing to a prethermalization mechanism. Our work elucidates the complex interplay between noise and symmetry-protected edge modes in a solid-state environment.

AB0879 Interim analysis of baseline characteristics and 12-week outcomes for a subset of patients with moderate-to-severe plaque psoriasis and psoriatic arthritis from the Psoriasis Study of Health Outcomes

Background

Approximately 30% of patients (pts) with plaque psoriasis (PsO) develop psoriatic arthritis (PsA)1, which is associated with high Psoriasis Area and Severity Index (PASI) and nail involvement. The Psoriasis Study of Health Outcomes (PSoHO) is a 3-year (yr), international, prospective, observational cohort study comparing the effectiveness of anti-IL-17A biologics to all other approved biologics in pts with moderate-to-severe PsO.

Objectives

This interim subset analysis describes the baseline characteristics and Week 12 (W12) effectiveness in pts with moderate-to-severe PsO and PsA in PSoHO.

Methods

Adults with moderate-to-severe PsO for ≥6 months who initiated/switched biologic treatment during routine medical care were enrolled. PsA diagnosis was recorded by the dermatologists based on the medical history and/or information provided by the patient. W12 effectiveness was assessed by the proportion of pts achieving almost clear or clear skin defined by ≥90% improvement in PASI, affected Body Surface Area (BSA), Dermatology Life Quality Index (DLQI), and Patient Global Assessment of Disease Severity (PatGA). Musculoskeletal endpoints were not collected. Data were analysed descriptively, using mean (standard deviation [SD]) or median ([Q1/Q3]) for continuous variables and n, % and 95% confidence limits for categorical variables.

Results

Overall, 1981 pts were enrolled in this study, of whom 461 (23.3%) had a PsA diagnosis and received either anti-IL-17A (n=227; 49.2%) or other biologics (n=234; 50.8%). This subset of pts had a mean age of 48.7 yrs and a median disease duration of 18.9 yrs for PsO and 5.6 yrs for PsA (Table 1).

Table 1.

Baseline characteristics for PsO patients with PsA. Mean (SD) reported for all available data for that measure, unless stated otherwise.

Overall (n=461)Anti-IL-17A (n=227)Other Biologics (n=234)Age, yrs48.7 (12.9)50.9 (12.9)46.6 (12.6)Male, n (%)232 (50.3)112 (49.3)120 (51.3)BMI (kg/m2)29.7 (6.2)29.8 (5.9)29.6 (6.4)Smoking status – Current, n (%)100 (25.4)41 (21.1)59 (29.5)Disease duration (PsA), yrs, median (Q1/Q3)5.6(2.2/13.1)5.6(2.0 / 13.8)5.5(2.3 / 12.8)Disease duration (PsO), yrs, median (Q1/Q3)18.9(9.7 / 28.6)18.9(9.2 / 30.3)18.7(10.1 / 27.3)Any previous biologic therapy, n (%)249 (54.0)123 (54.2)126 (53.8)PASI14.3 (9.3)13.6 (8.1)15.0 (10.3)BSA, %21.7 (19.4)19.8 (17.3)23.5 (21.1)mNAPSI16.6 (22.8)16.5 (25.5)16.7 (20.1)Presence of nail PsO, n (%)217 (47.2)103 (45.4)114 (48.9)PatGA3.5 (1.2)3.5 (1.3)3.6 (1.2)DLQI13.6 (7.9)13.4 (7.8)13.7 (8.0)HADS Depression score >10, n (%)73 (19.3)38 (20.5)35 (18.1)HADS Anxiety score >10, n (%)124 (32.8)62 (33.5)62 (32.1)

BMI = Body Mass Index; BSA = Body Surface Area; DLQI = Dermatology Life Quality Index; HADS = Hospital Anxiety and Depression Scale; HADS >10 indicates significant symptoms of depression/anxiety; mNAPSI = Modified Nail Psoriasis Severity Index; PASI = Psoriasis Area and Severity Index; PatGA = Patient Global Assessment of Disease Severity; Q1/Q3 = Quartile 1/3.

At W12, 62.4% and 42.6% of anti-IL-17A-treated pts achieved PASI90 and PASI100, respectively, compared with 34.2% and 16.8% in the other biologics cohort, respectively (Figure 1). BSA <3% was reached by 70.9% of anti-IL-17A-treated pts and 49.5% in the other biologics cohort, while 71.2% and 44.8%, respectively, reached PatGA 0/1. Among pts with baseline DLQI ≥2, 38.0% and 27.1% of the anti-IL-17A and other biologics cohorts, respectively, reached DLQI 0/1.

Figure 1.

Percentage of patients receiving anti-IL-17A or other biologics who achieved PASI75/90/100, absolute PASI ≤1, BSA <3%, PatGA 0/1 and DLQI 0/1 (baseline DLQI ≥2) at Week 12. Bars represent upper 95% confidence limits.

Conclusion

The effectiveness of blocking IL-17A on skin manifestations and on quality-of-life improvements in pts with PsO and PsA in the real-world study was consistent with observations from clinical trials.

References

[1]Zabotti A, et al. RMD Open 2019;5: e001067

Disclosure of Interests

Lars Erik Kristensen Speakers bureau: Pfizer, AbbVie, Amgen, UCB, Gilead, Biogen, BMS, MSD, Novartis, Eli Lilly, and Janssen pharmaceuticals., Consultant of: Pfizer, AbbVie, Amgen, UCB, Gilead, Biogen, BMS, MSD, Novartis, Eli Lilly, and Janssen pharmaceuticals., Grant/research support from: IIT research grants from Pfizer, AbbVie, UCB, Gilead, Biogen, Novartis, Eli Lilly, and Janssen pharmaceuticals., Frank Behrens Speakers bureau: Amgen, AbbVie, Pfizer, Roche, Chugai, UCB, BMS, Celgene, MSD, Novartis, Biotest, Janssen, Genzyme, Eli Lilly, Boehringer and Sandoz, Consultant of: Amgen, AbbVie, Pfizer, Roche, Chugai, UCB, BMS, Celgene, MSD, Novartis, Biotest, Janssen, Genzyme, Eli Lilly, Boehringer and Sandoz, Grant/research support from: AbbVie, Pfizer, Roche, Chugai, GSK and Janssen, Luis Puig Speakers bureau: Celgene, Janssen, Eli Lilly, Novartis, Pfizer, Consultant of: Abbvie, Almirall, Amgen, Baxalta, Biogen, Boehringer Ingelheim, Bristol Myers Squibb, Celgene, Fresenius-Kabi, Janssen, JS BIOCAD, Leo-Pharma, Eli Lilly, Mylan, Novartis, Pfizer, Regeneron, Roche, Sandoz, Samsung-Bioepis, Sanofi, UCB, Grant/research support from: Abbvie, Almirall, Amgen, Boehringer Ingelheim, Celgene, Janssen, Leo-Pharma, Eli Lilly, Novartis, Pfizer, Regeneron, Roche, Sanofi, UCB, Adam Reich Speakers bureau: Abbvie, Novartis, Janssen, Pfizer, Sandoz, Galderma, Eli Lilly, Consultant of: Abbvie, Novartis, Janssen, Pfizer, Sandoz, Galderma, Eli Lilly, Thorsten Holzkaemper Shareholder of: Eli Lilly and Company, Employee of: Eli Lilly and Company, Alan Brnabic Shareholder of: Eli Lilly and Company, Employee of: Eli Lilly and Company, Khai Ng Shareholder of: Eli Lilly and Company, Employee of: Eli Lilly and Company, Soyi Liu Leage Shareholder of: Eli Lilly and Company, Employee of: Eli Lilly and Company, Christopher Schuster Shareholder of: Eli Lilly and Company, Employee of: Eli Lilly and Company, Andreas Pinter Speakers bureau: AbbVie, Almirall-Hermal, Amgen, Biogen Idec, Biontec, Boehringer-Ingelheim, Celgene, GSK, Eli Lilly, Galderma, Hexal, Janssen, LEO-Pharma, MC2, Medac, Merck Serono, Mitsubishi, MSD, Novartis, Pascoe, Pfizer, Tigercat Pharma, Regeneron, Roche, Sandoz Biopharmaceuticals, Sanofi-Genzyme, Schering-Plough and UCB Pharma, Consultant of: AbbVie, Almirall-Hermal, Amgen, Biogen Idec, Biontec, Boehringer-Ingelheim, Celgene, GSK, Eli Lilly, Galderma, Hexal, Janssen, LEO-Pharma, MC2, Medac, Merck Serono, Mitsubishi, MSD, Novartis, Pascoe, Pfizer, Tigercat Pharma, Regeneron, Roche, Sandoz Biopharmaceuticals, Sanofi-Genzyme, Schering-Plough and UCB Pharma

A note on residual M-distances for identifying aberrant response patterns

Although a statistical model might fit well to a large proportion of the individuals of a random sample, some individuals might give 'unusual' responses that are not well explained by the hypothesized model. If individual responses are given as continuous response vectors, M-distances can be used to produce real valued indicators of how well an individual's response vector corresponds to a covariance structure implied by a psychometric model. In this note, we focus on the so-called one-factor model. Two M-distances, d_si and d_ri , which are sensitive to different aspects of the assumed factor model, have been proposed. While one of the M-distances, d_ri , has been derived based on Bartlett factor scores, in this note we show that the second M-distance, d_si , can be derived in an analogous fashion based on Thomson factor scores.

Screening of biological activities of fungi associated with pistachio bark beetle, Chaetoptelius vestitus (Coleoptera, Curculionidae), infesting pistachio cultivations in Tunisia

AIMS

In this study, we aimed to explore the enzymatic diversity, the entomopathogenic and the antimicrobial potentialities of fungi associated with the pistachio bark beetle, Chaetoptelius vestitus.

METHODS AND RESULTS

A total of 40 isolates were screened for enzymatic diversity. Most of them, 92·5%, were able to produce at least two of the screened enzymes. Pathogenic assays performed on C. vestitus showed a high entomopathogenic activity of the isolates Ata_io_1 (A. tamarii), Fve_io_1 (F. verticillioides), Tpi_io_1 (T. pinophilus), Pal_io_1 (P. album), Pbi_io_2 (Penicillium bilaiae) and Pch_io_1 (P. chrysogenum), as based on mean mortality of C. vestitus. A screening of antimicrobial activity using well diffusion method showed that the isolates Tro_io_1 (T. pinophilus), Tat_io_1 (T. atroroseus) and Pch_io_1 (P. chrysogenum) presented the highest antibacterial activity. Furthermore, Mgu_io_1 (M. guilliermondii), Asc_io_1 (A. sclerotiorum), Ata_io_1 (A. tamarii), G. lavendula (Gla_io_1), Pva_io_1 (P. variotii), Pul_io_1 (P. ulaiense), Tat_io_1 (T. atroroseus) and Tro_io_1 (T. roseum) were active against at least two of the three tested fungal phytopathogens.

CONCLUSIONS

Fungal isolates representing entomopathogenic activity and a broad spectrum of antimicrobial activities can be considered as promising resources for biological pistachio trees protection.

SIGNIFICANCE AND IMPACT OF THE STUDY

Fungi associated with C. vestitus were investigated for detecting their potential biotechnological applications.

Comments on ‘French guidelines on the use of systemic treatments for moderate‐to‐severe psoriasis in adults’

Linked article: F. Amatore et al. J Eur Acad Dermatol Venereol 2019; 33: 464–483. https://doi.org/10.1111/jdv.15340

A Graded Response Model Framework for Questionnaires With Uniform Response Formats

Questionnaires with uniform-ordered categorical response formats are widely applied in psychology. Muraki proposed a modified graded response model accounting for the items' uniform response formats by assuming identical threshold parameters defining the category boundaries for all items. What is not well known is that there is a set of closely related models, which similarly assume identical thresholds. The present article gives a framework illustrating the differences between these models and their utility for understanding questionnaire responses in detail. The models are explained as constrained cases of a one-dimensional factor model for ordered categorical data. Furthermore, the authors show that the models can be written and fitted as structural equation models, which allows for a very flexible and general purpose use. Instructions on implementing the models in Mplus and SAS PROC NLMIXED are given.

An optimized targeted Next-Generation Sequencing approach for sensitive detection of single nucleotide variants

•

NGS based detection of low-level SNVs is feasible with sensitivities up to 10⁻⁴.

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PCR-induced bias could be significantly reduced by the choice of adequate enzymes.

•

The prevalent transition vs. transversion bias affects site-specific detection limits.

•

Results from clinical data validated the feasibility of NGS-based MRD detection.

•

Results help to select suitable biomarkers for MRD quantification.

Monitoring of minimal residual disease (MRD) has become an important clinical aspect for early relapse detection during follow-up care after cancer treatment. Still, the sensitive detection of single base pair point mutations via Next-Generation Sequencing (NGS) is hampered mainly due to high substitution error rates. We evaluated the use of NGS for the detection of low-level variants on an Ion Torrent PGM system. As a model case we used the c.1849G > T (p.Val617Phe) mutation of the JAK2-gene. Several reaction parameters (e.g. choice of DNA-polymerase) were evaluated and a comprehensive analysis of substitution errors was performed. Using optimized conditions, we reliably detected JAK2 c.1849G > T VAFs in the range of 0.01–0.0015% which, in combination with results obtained from clinical data, validated the feasibility of NGS-based MRD detection. Particularly, PCR-induced transitions (mainly G > A and C > T) were the major source of error, which could be significantly reduced by the application of proofreading enzymes. The integration of NGS results for several common point mutations in various oncogenes (i.e. IDH1 and 2, c-KIT, DNMT3A, NRAS, KRAS, BRAF) revealed that the prevalent transition vs. transversion bias (3.57:1) has an impact on site-specific detection limits of low-level mutations. These results may help to select suitable markers for MRD detection and to identify individual cut-offs for detection and quantification.

The Graded Response Differential Discrimination Model Accounting for Extreme Response Style

Extreme response style or, more generally, individual differences in response spacing have been shown to be an influential bias when analyzing questionnaire data. Recently a promising model adjusting for this bias - the differential discrimination model - has been proposed. An advantage to other related approaches is that the model can be fitted using standard structural equation modeling software. However, the model is designed for analyzing continuous item responses, whereas graded response formats are certainly more prominent in behavioral sciences. To resolve this limitation, the present article extends the differential discrimination model to analyzing graded responses. Empirical examples as well as a small simulation study are presented.

Composite vector formulation for multiple siRNA delivery as a host targeting antiviral in a cell culture model of hepatitis C virus (HCV) infection

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease and cancer worldwide. RNA interference (RNAi)-based gene therapies have emerged recently as a promising tool to treat chronic viral infections. Indeed, small interfering RNAs (siRNAs) provide an opportunity to target host factors required for the viral life cycle. In this study, we evaluated a novel nanovector-based approach for siRNA delivery in a model of chronically infected hepatic cells. We designed original composite nanoparticles by coating the calcium phosphate core with siRNAs targeting HCV host-factors and pyridylthiourea-grafted polyethyleneimine (πPEI). Using combinations of different siRNAs, we observed an efficient and prolonged decrease of HCV replication. Moreover, we showed that the layer-by-layer technique of coating applied to our nanoparticles triggers a sequential release of siRNAs acting on different steps of the HCV life cycle. Together, our results demonstrate the efficacy of these nanoparticles for siRNA delivery and open new perspectives for antiviral therapies.

The Relationship of ANOVA Models with Random Effects and Repeated Measurement Designs

Understanding ANOVA models is often difficult because of the large amount of different experimental designs presented in applied textbooks.This article shows how different experimental designs arise out of the variation of three basic distinctions: block versus treatment factors, fixed versus random factors, and crossed versus nested factors.Once it is understood how each distinction influences the statistical analysis, the amount of experimental designs can be considerably reduced, because sometimes seemingly different experimental designs are essentially equivalent.This is shown by an example comparing a two-way analysis of variance model to a three-factor partially nested design.Furthermore, the way each distinction influences the statistical analysis of an experimental design can simplify the computational effort of the analysis because virtually every basic ANOVA procedure implemented in common statistical software packages can be used to fit more complex ANOVA models that are usually analyzed using special computer modules.

Sampling Schemes and the Selection of Log-Linear Models for Longitudinal Data

Because the selection of a sampling scheme can have strong effects on the admissibility of log-linear models, the authors discuss these effects for the multinomial and the product multinomial sampling schemes for prospective and retrospective sampling.In multi-nomial sampling, marginal frequencies are not fixed a priori.In product multinomial sampling, uni-or multidimensional marginal frequencies are considered fixed.Therefore, models must fit these marginal frequencies exactly.A data example illustrates model selection using data from a project of family development.

Consistent Differential Discrimination Model Estimation

A novel factor-analytic model-the differential discrimination model-for assessing individual differences in scale use has been recently introduced, together with a three-stage estimation approach for model fitting. Unfortunately, the second-stage estimator and, as a consequence, the third-stage estimator of this procedure are not consistent. In this article we show that (a) the differential discrimination model can be expressed in a structural equation model framework, and (b) consistent and simultaneous estimation of all model parameters can be achieved using standard SEM software.

The road to freedom: Quantitative developmental methodology in the third millennium

In this article we ask three questions. First, what is the relationship between substantive psychological research and research in the area of applied quantitative, statistical methods? Second, what is the development that applied quantitative methodology will undergo in the foreseeable future? Third, will this development affect the future of psychological research? The answers to these questions are cast in terms of six trends and three anticipated problems. The trends are: (1) increase in the number of available statistical methods; (2) substantive thinking triggers the development of new statistical methods; (3) statistical methods become increasingly flexible; (4) computers do the thinking; (5) there will be new paradigms such as the person-oriented perspective; and (6) statistical methods will be custom-tailored to substantive questions. The general tenor of the discussion of these trends is that the number of possibilities will increase and the researcher will be freed from method-specific constraints. The three problem trends are: (1) the choice between methods of analysis becomes increasingly difficult; (2) cases of misuse of statistics will become more frequent; and (3) the role of the methodologist will change such that more substantive knowledge will be required. In addition, issues of training of methodologists and financing research are discussed. The general outlook is depicted as encouraging.

Modelling Synergy using Manifest Categorical Variables

This paper discusses methods to model the concept of synergy at the level of manifest categorical variables. First, a classification of concepts of synergy is presented. A dditive and nonadditive concepts of synergy are distinguished. Most prominent among the nonadditive concepts is superadditive synergy. Examples are given from the natural sciences and the social sciences. M delling focuses on the relationship between the agents involved in a synergetic process. These relationships are expressed in form of contrasts, expressed in effect coding vectors in design matrices for nonstandard log-linear models. A method by Schuster is used to transform design matrices such that parameters reflect the proposed relationships. A n example reanalyses data presented by Bishop, Fienberg, and Holland (1975) that describe the development of thromboembolisms in women who differ in their patterns of contraceptive use and smoking. Alternative methods of analysis are com pared. Implications for developmental research are discussed.

Determining the Meaning of Parameters in Multilevel Models for Longitudinal Data

This paper is concerned with parameter interpretation in longitudinal, multilevel models. Models are described that consider repeated observations nested within individuals. These models typically first estimate subject-specific parameters for growth curves that describe the development of some observed variable overtime. Examples of such descriptors include polynomials. It is shown that interpretation of polynomial parameters can be facilitated by linear transformations. Examples of such transformations include centring (i.e. subtracting the mean from raw data). When parameters are specified such that they have no straightforward meaning at the first level of analysis, interpretation problems carry over to the second and higher levels. Therefore, proper specification of models at the first level is of utmost importance. Methods of transformation are introduced. Examples illustrate the method using data that describe children’s vocabulary development in the second year of life.

Diagnostic approach in lymphoplasmacytic plaque

BACKGROUND

Lymphoplasmacytic plaque (LPP) is a recently described rare skin disease characterized by a dense dermal lymphohistiocytic infiltrate with polyclonal plasma cells. The clinical picture is distinct with reddish to brownish plaque with a predilection for the lower leg. LPP typically affects children.

OBJECTIVE

To define clinical and histologic criteria of LPP and to develop a diagnostic flow chart.

METHODS

We investigated six of our own LPP cases. Immunoglobulin light chains, IgG, IgG4, CD31, CD163 as a histiocytic marker were examined by immunohistochemistry. PCR-based molecular studies were conducted for borrelia sp., mycobacterial and leishmania sp. Moreover, 10 cases, which have been reported in the literature, were checked for the same features.

RESULTS

We could differentiate three main histological patterns (superficial band-like only, [deep] dermal only and mixed). Acanthosis and interface dermatitis are key features in cases with a superficial band-like or mixed infiltrate. Granulomas and giant cells could be only found in about 30% of the cases. The number of plasma cells was variable accounting for 5-40% of the infiltrate. The number of blood vessels was increased in the majority of the cases. 'Free-floating' collagen bundles surrounded by histiocytes (pseudorosettes) were identified as a new histological feature. An infectious agent could be excluded in all cases.

CONCLUSIONS

LPP is a long-standing skin disease, which may also occur in adults and in other body regions than the lower leg. Reproducible clinical and histological criteria allow delineating a diagnostic work-up for LPP.

Shifting and extension of phenological periods with increasing temperature along elevational transects in southern Bavaria

The impact of global warming on phenology has been widely studied, and almost consistently advancing spring events have been reported. Especially in alpine regions, an extraordinary rapid warming has been observed in the last decades. However, little is known about phenological phases over the whole vegetation period at high elevations. We observed 12 phenological phases of seven tree species and measured air temperature at 42 sites along four transects of about 1000 m elevational range in the years 2010 and 2011 near Garmisch-Partenkirchen, Germany. Site- and species-specific onset dates for the phenological phases were determined and related to elevation, temperature lapse rates and site-specific temperature sums. Increasing temperatures induced advanced spring and delayed autumn phases, in which both yielded similar magnitudes. Delayed leaf senescence could therefore have been underestimated until now in extending the vegetation period. Not only the vegetation period, but also phenological periods extended with increasing temperature. Moreover, sensitivity to elevation and temperature strongly depends on the specific phenological phase. Differences between species and groups of species (deciduous, evergreen, high elevation) were found in onset dates, phenological response rates and also in the effect of chilling and forcing temperatures. Increased chilling days highly reduced forcing temperature requirements for deciduous trees, but less for evergreen trees. The problem of shifted species associations and phenological mismatches due to species-specific responses to increasing temperature is a recent topic in ecological research. Therefore, we consider our findings from this novel, dense observation network in an alpine area of particular importance to deepen knowledge on phenological responses to climate change.

Evaluation of exercise capacity after severe stroke using robotics-assisted treadmill exercise: a proof-of-concept study

BACKGROUND

Robotics-assisted treadmill exercise (RATE) with focus on motor recovery has become popular in early post-stroke rehabilitation but low endurance for exercise is highly prevalent in these individuals. This study aimed to develop an exercise testing method using robotics-assisted treadmill exercise to evaluate aerobic capacity after severe stroke.

METHODS

Constant load testing (CLT) based on body weight support (BWS) control, and incremental exercise testing (IET) based on guidance force (GF) control were implemented during RATE. Analyses focussed on step change, step response kinetics, and peak performance parameters of oxygen uptake.

RESULTS

Three subjects with severe motor impairment 16-23 days post-stroke were included. CLT yielded reasonable step change values in oxygen uptake, whereas response kinetics of oxygen uptake showed low goodness of fit. Peak performance parameters were not obtained during IET.

CONCLUSION

Exercise testing in post-stroke individuals with severe motor impairments using a BWS control strategy for CLT is deemed feasible and safe. Our approach yielded reasonable results regarding cardiovascular performance parameters. IET based on GF control does not provoke peak cardiovascular performance due to uncoordinated walking patterns. GF control needs further development to optimally demand active participation during RATE. The findings warrant further research regarding the evaluation of exercise capacity after severe stroke.

About the change in boiling behaviour of water with coolant additives in PWR

The present study investigates the effect of boric acid and lithium hydroxide on flow boiling phenomena in pressurized water reactors. The experiments were conducted in a boiling loop with up to 40 bar and 250 °C. The bubble size distribution was determined with a wire-mesh sensor. The results showed no indication that reactor-typical concentrations of boric acid or lithium hydroxide have a safety-relevant influence on the boiling behavior in pressurized water reactors.