Enhanced Collateral Growth by Double Transplantation of Gene-Nucleofected Fibroblasts in Ischemic Hindlimb of Rats

BACKGROUND: Induction of neovascularization by releasing therapeutic growth factors is a promising application of cell-based gene therapy to treat ischemia-related problems. In the present study, we have developed a new strategy based on nucleofection with alternative solution and cuvette to promote collateral growth and re-establishment of circulation in ischemic limbs using double transplantation of gene nucleofected primary cultures of fibroblasts, which were isolated from rat receiving such therapy. METHODS AND RESULTS: Rat dermal fibroblasts were nucleofected ex vivo to release bFGF or VEGF165 in a hindlimb ischemia model in vivo. After femoral artery ligation, gene-modified cells were injected intramuscularly. One week post injection, local confined plasmid expression and transient distributions of the plasmids in other organs were detected by quantitative PCR. Quantitative micro-CT analyses showed improvements of vascularization in the ischemic zone (No. of collateral vessels via micro CT: 6.8±2.3 vs. 10.1±2.6; p<0.05). Moreover, improved collateral proliferation (BrdU incorporation: 0.48±0.05 vs. 0.57±0.05; p<0.05) and increase in blood perfusion (microspheres ratio: gastrocnemius: 0.41±0.10 vs. 0.50±0.11; p<0.05; soleus ratio: soleus: 0.42±0.08 vs. 0.60±0.08; p<0.01) in the lower hindlimb were also observed. CONCLUSIONS: These results demonstrate the feasibility and effectiveness of double transplantation of gene nucleofected primary fibroblasts in producing growth factors and promoting the formation of collateral circulation in ischemic hindlimb, suggesting that isolation and preparation of gene nucleofected cells from individual accepting gene therapy may be an alternative strategy for treating limb ischemia related diseases

Isolating the impact of antipsychotic medication on metabolic health : secondary analysis of a randomized controlled trial of antipsychotic medication versus placebo in antipsychotic medication naïve first‐episode psychosis (the STAGES study)

Background Cardiovascular and metabolic diseases are the leading contributors to the early mortality associated with psychotic disorders. To date, it has not been possible to disentangle the effect of medication and non-medication factors on the physical health of people with a first episode of psychosis (FEP). This study aimed to isolate the effects of antipsychotic medication on anthropometric measurements, fasting glucose and lipids. Methods This study utilized data from a triple-blind randomized placebo-controlled trial comparing two groups of antipsychotic-naïve young people with a FEP who were randomized to receive a second-generation antipsychotic medication (FEP-medication group) or placebo (FEP-placebo group) for 6 months. Twenty-seven control participants were also recruited. Results Eighty-one participants commenced the trial; 69.1% completed at least 3 months of the intervention and 33.3% completed the full 6 months. The FEP-placebo group gained a mean of 2.4 kg (±4.9) compared to 1.1 kg (±4.9) in the control participants (t = 0.76, p = .45). After controlling for multiple analyses, there was no difference in blood pressure, waist circumference or heart rate between the FEP-placebo group and controls. After 6 months, the FEP medication group had gained 4.1 kg (±4.5), higher than those receiving placebo but not statistically significant (t = 0.8, p = .44). There were no differences in fasting glucose or lipids between the FEP groups after 3 months. Conclusions While limited by small numbers and high attrition, these findings indicate that some of the metabolic complications observed in psychotic disorders could be attributable to factors other than medication. This emphasizes the need to deliver physical health interventions early in the course of FEP

Suppressing quantum errors by scaling a surface code logical qubit

Practical quantum computing will require error rates that are well below what is achievable with physical qubits. Quantum error correction offers a path to algorithmically-relevant error rates by encoding logical qubits within many physical qubits, where increasing the number of physical qubits enhances protection against physical errors. However, introducing more qubits also increases the number of error sources, so the density of errors must be sufficiently low in order for logical performance to improve with increasing code size. Here, we report the measurement of logical qubit performance scaling across multiple code sizes, and demonstrate that our system of superconducting qubits has sufficient performance to overcome the additional errors from increasing qubit number. We find our distance-5 surface code logical qubit modestly outperforms an ensemble of distance-3 logical qubits on average, both in terms of logical error probability over 25 cycles and logical error per cycle ($2.914\%\pm 0.016\%$ compared to $3.028\%\pm 0.023\%$). To investigate damaging, low-probability error sources, we run a distance-25 repetition code and observe a $1.7\times10^{-6}$ logical error per round floor set by a single high-energy event ($1.6\times10^{-7}$ when excluding this event). We are able to accurately model our experiment, and from this model we can extract error budgets that highlight the biggest challenges for future systems. These results mark the first experimental demonstration where quantum error correction begins to improve performance with increasing qubit number, illuminating the path to reaching the logical error rates required for computation.Comment: Main text: 6 pages, 4 figures. v2: Update author list, references, Fig. S12, Table I

Measurement-induced entanglement and teleportation on a noisy quantum processor

Measurement has a special role in quantum theory: by collapsing the wavefunction it can enable phenomena such as teleportation 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-time that go beyond established paradigms for characterizing phases, either in or out of equilibrium. On present-day NISQ processors, the experimental realization of this physics is challenging due to noise, hardware limitations, and the stochastic nature of quantum measurement. Here we address each of these experimental challenges and investigate measurement-induced quantum information phases on up to 70 superconducting qubits. By leveraging the interchangeability of space and time, we use a duality mapping, to avoid mid-circuit measurement and access different manifestations of the underlying phases -- from entanglement scaling to measurement-induced teleportation -- in a unified way. We obtain finite-size signatures of a phase transition with a decoding protocol that correlates the experimental measurement record with classical simulation data. The phases display sharply different sensitivity to noise, which we exploit to turn an inherent hardware limitation into a useful diagnostic. Our work demonstrates an approach to realize measurement-induced physics at scales that are at the limits of current NISQ processors

Non-Abelian braiding of graph vertices in a superconducting processor

Indistinguishability of particles is a fundamental principle of quantum mechanics. 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. However, in two spatial dimensions, an intriguing possibility exists: braiding of non-Abelian anyons causes rotations in a space of topologically degenerate wavefunctions. 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, 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. While efforts on conventional solid-state platforms typically involve Hamiltonian dynamics of quasi-particles, superconducting quantum processors allow for directly manipulating the many-body wavefunction via unitary gates. Building on predictions that stabilizer codes can host projective non-Abelian Ising anyons, we implement a generalized stabilizer code and unitary protocol 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 employing the anyons for quantum computation and utilize 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 toward fault-tolerant quantum computing

Developing Sustainable Open Source Strategies for Research

The objective of this project was to develop a set of policy recommendations and guidelines for the IGB in Germany that would be used to implement open source publication methods. Open source practices can increase the accessibility, transparency, and collaborative ability of research by changing how software that is created as a part of research is published. This project was conducted using a series of surveys and interviews with IGB staff as well as individuals from other fields. We produced a policy brief for the administration of the IGB on what policy changes would enable open source practices as well as a flyer for distribution at the IGB that described why open source publication is important

Gradients of striatal function in antipsychotic-free first-episode psychosis and schizotypy

Abstract Both psychotic illness and subclinical psychosis-like experiences (PLEs) have been associated with cortico-striatal dysfunction. This work has largely relied on a discrete parcellation of the striatum into distinct functional areas, but recent evidence suggests that the striatum comprises multiple overlapping and smoothly varying gradients (i.e., modes) of functional organization. Here, we investigated two of these functional connectivity modes, previously associated with variations in the topographic patterning of cortico-striatal connectivity (first-order gradient), and dopaminergic innervation of the striatum (second-order gradient), and assessed continuities in striatal function from subclinical to clinical domains. We applied connectopic mapping to resting-state fMRI data to obtain the first-order and second-order striatal connectivity modes in two distinct samples: (1) 56 antipsychotic-free patients (26 females) with first-episode psychosis (FEP) and 27 healthy controls (17 females); and (2) a community-based cohort of 377 healthy individuals (213 females) comprehensively assessed for subclinical PLEs and schizotypy. The first-order “cortico-striatal” and second-order “dopaminergic” connectivity gradients were significantly different in FEP patients compared to controls bilaterally. In the independent sample of healthy individuals, variations in the left first-order “cortico-striatal” connectivity gradient were associated with inter-individual differences in a factor capturing general schizotypy and PLE severity. The presumed cortico-striatal connectivity gradient was implicated in both subclinical and clinical cohorts, suggesting that variations in its organization may represent a neurobiological trait marker across the psychosis continuum. Disruption of the presumed dopaminergic gradient was only noticeable in patients, suggesting that neurotransmitter dysfunction may be more apparent to clinical illness