66 research outputs found
Learning fermionic correlations by evolving with random translationally invariant Hamiltonians
Schemes of classical shadows have been developed to facilitate the read-out
of digital quantum devices, but similar tools for analog quantum simulators are
scarce and experimentally impractical. In this work, we provide a measurement
scheme for fermionic quantum devices that estimates second and fourth order
correlation functions by means of free fermionic, translationally invariant
evolutions - or quenches - and measurements in the mode occupation number
basis. We precisely characterize what correlation functions can be recovered
and equip the estimates with rigorous bounds on sample complexities, a
particularly important feature in light of the difficulty of getting good
statistics in reasonable experimental platforms, with measurements being slow.
Finally, we demonstrate how our procedure can be approximately implemented with
just nearest-neighbour, translationally invariant hopping quenches, a very
plausible procedure under current experimental requirements, and requiring only
random time-evolution with respect to a single native Hamiltonian. On a
conceptual level, this work brings the idea of classical shadows to the realm
of large scale analog quantum simulators.Comment: 27 pages, 10 figure
Enhanced surveillance of invasive listeriosis in the Lombardy region, Italy, in the years 2006-2010 reveals major clones and an increase in serotype 1/2a
BACKGROUND: Invasive listeriosis is a rare, life-threatening foodborne disease. Lombardy, an Italian region accounting for 16% of the total population, reported 55% of all listeriosis cases in the years 2006-2010. The aim of our study was to provide a snapshot of listeriosis epidemiology in this region after the implementation of a voluntary laboratory-based surveillance system. METHODS: We characterized by serotyping, pulsed-field gel electrophoresis, multilocus sequence typing and detection of epidemic clone markers, 134 isolates from 132 listeriosis cases, including 15 pregnancy-related cases, occurring in the years 2006-2010 in Lombardy. Demographic and clinical characteristics of cases have also been described. RESULTS: The mean age of non pregnancy-associated cases was 64.7 years, with 55.9% of cases being older than 65 years. Cases having no underlying medical conditions accounted for 11.6%. The all-cause fatality rate of 83 cases with a known survival outcome was 25.3%. Serotypes 1/2a and 4b comprised 52.2% and 38.8% of isolates, respectively. Seventy-three AscI pulsotypes and 25 sequence types assigned to 23 clonal complexes were recognized. Moreover, 53 (39.5%) isolates tested positive for the epidemic clone markers. Twelve molecular subtype clusters including at least three isolates were detected, with cluster 11 (1/2a/ST38) including 31 isolates identified during the entire study period. No outbreaks were notified to public health authorities during this period. CONCLUSIONS: The findings of our study proved that epidemiology of listeriosis in Lombardy is characterized by a high prevalence of major clones and the increasing role of serotype 1/2a. Molecular subtyping is an essential tool in the epidemiology and surveillance of listeriosis. Rapid molecular cluster detection could alert about putative outbreaks, thus increasing the chance of detecting and inactivating routes of transmission
Listeria monocytogenes serotypes in human infections (Italy, 2000-2010)
BACKGROUND: In developed countries invasive listeriosis is an infection of great concern to public health to due its clinical severity and high fatality rate, despite its low incidence. In Europe, statistically significant increasing trends in listeriosis notification rates from 2005 to 2009 were noted in Austria, Denmark, Hungary, Italy, Spain and Sweden. MATERIALS AND METHODS: The standardized techniques based on phenotype to typing Listeria monocytogenes is the serotyping. In Europe, as elsewhere in the world, about 95% of L. monocytogenes strains isolated from clinical and food samples belongs to serovars 1/2a, 1/2b, 1/2c and 4b. RESULTS: The target of this work is to draw attention to this important and atypical foodborne disease, reporting epidemiological data and serotypes distribution of 251 human L. monocytogenes isolates reported during 2000-2010 to Veterinary Public Health and Food Safety Department of Istituto Superiore di SanitĂ , focusing on epidemiological trend of invasive listeriosis in Lombardia, a North Italian Region. The serotypes most frequently identified are 1/2a, 4b, 1/2b (in total 92%), but the detection of uncommon serotypes is not missing (1/2c, 3a, 3b, 4d). CONCLUSIONS: In Italy the surveillance laboratory network, as well as the foodborne disease network (ENTER-NET), has revealed in the last 11 years an increase trend of listeriosis cases reported likewise with results of Notificable National Infectious Disease surveillance System. This is probably due to a real increase of listeriosis, even if there is a greater sensitivity of the network in some regions
Altered hepatic glucose homeostasis in AnxA6-KO mice fed a high-fat diet
Annexin A6 (AnxA6) controls cholesterol and membrane transport in endo- and exocytosis,and modulates triglyceride accumulation and storage. In addition, AnxA6 acts as a scaffolding protein for negative regulators of growth factor receptors and their effector pathways in many different cell types. Here we investigated the role of AnxA6 in the regulation of whole body lipid metabolism and insulin-regulated glucose homeostasis. Therefore, wildtype (WT) and AnxA6-knockout (KO) mice were fed a high-fat diet (HFD) for 17 weeks. During the course of HFD feeding, AnxA6-KO mice gained less weight compared to controls, which correlated with reduced adiposity. Systemic triglyceride and cholesterol levels of HFD-fed control and AnxA6-KO mice were comparable, with slightly elevated high density lipoprotein (HDL) and reduced triglyceride-rich lipoprotein (TRL) levels in AnxA6-KO mice. AnxA6-KO mice displayed a trend towards improved insulin sensitivity in oral glucose and insulin tolerance tests (OGTT, ITT), which correlated with increased insulin-inducible phosphorylation of protein kinase B (Akt) and ribosomal protein S6 kinase (S6) in liver extracts. However,HFD-fed AnxA6-KO mice failed to downregulate hepatic gluconeogenesis, despite similar insulin levels and insulin signaling activity, as well as expression profiles of insulin-sensitive transcription factors to controls. In addition, increased glycogen storage in livers of HFDand chow-fed AnxA6-KO animals was observed. Together with an inability to reduce glucose production upon insulin exposure in AnxA6-depleted HuH7 hepatocytes, this implicates AnxA6 contributing to the fine-tuning of hepatic glucose metabolism with potential consequences for the systemic control of glucose in health and disease
Trends in biomedical analysis of red blood cells – Raman spectroscopy against other spectroscopic, microscopic and classical techniques
Application of modern and innovative spectroscopic and microscopic approaches to biomedical analysis opens new horizons and sheds new light on many unexplored scientific territories. In this review, we critically summarize up-to-date Raman-based methodologies for red blood cells (RBCs) analysis used in biology and medicine, and compare them with both classical, as well as other spectroscopic and microscopic approaches. The main emphasis is placed on the advantages, disadvantages and capabilities of each technique for detection of RBC deteriorations and RBC-related diseases. Although currently used classical techniques of medical analysts serve as a gold standard for clinicians in diagnosis of erythropathies, they provide insufficient insight into RBC alterations at the molecular level. In addition, there is a demand for non-destructive and label-free analytical techniques for rapid detection and diagnosis of erythropathies. Their recognition often requires multimodal methodology comprising application of methods including sophisticated spectroscopy-based techniques, where Raman-based approaches play an important role
Annexin A6 is critical to maintain glucose homeostasis and survival during liver regeneration in mice
Background and aims: Liver regeneration requires the organized and sequential activation of events that lead to restoration of hepatic mass. During this process, other vital liver functions need to be preserved, such as maintenance of blood glucose homeostasis, balancing the degradation of hepatic glycogen stores, and gluconeogenesis (GNG). Under metabolic stress, alanine is the main hepatic gluconeogenic substrate, and its availability is the rate-limiting step in this pathway. Na+ -coupled neutral amino acid transporters (SNATs) 2 and 4 are believed to facilitate hepatic alanine uptake. In previous studies, we demonstrated that a member of the Ca2+ -dependent phospholipid binding annexins, Annexin A6 (AnxA6), regulates membrane trafficking along endo- and exocytic pathways. Yet, although AnxA6 is abundantly expressed in the liver, its function in hepatic physiology remains unknown. In this study, we investigated the potential contribution of AnxA6 in liver regeneration. Approach and results: Utilizing AnxA6 knockout mice (AnxA6-/- ), we challenged liver function after partial hepatectomy (PHx), inducing acute proliferative and metabolic stress. Biochemical and immunofluorescent approaches were used to dissect AnxA6-/- mice liver proliferation and energetic metabolism. Most strikingly, AnxA6-/- mice exhibited low survival after PHx. This was associated with an irreversible and progressive drop of blood glucose levels. Whereas exogenous glucose administration or restoration of hepatic AnxA6 expression rescued AnxA6-/- mice survival after PHx, the sustained hypoglycemia in partially hepatectomized AnxA6-/- mice was the consequence of an impaired alanine-dependent GNG in AnxA6-/- hepatocytes. Mechanistically, cytoplasmic SNAT4 failed to recycle to the sinusoidal plasma membrane of AnxA6-/- hepatocytes 48 hours after PHx, impairing alanine uptake and, consequently, glucose production. Conclusions: We conclude that the lack of AnxA6 compromises alanine-dependent GNG and liver regeneration in mice
PCYT1A Regulates Phosphatidylcholine Homeostasis from the Inner Nuclear Membrane in Response to Membrane Stored Curvature Elastic Stress
PCYT1A Regulates Phosphatidylcholine Homeostasis from the Inner Nuclear Membrane in Response to Membrane Stored Curvature Elastic Stress.
Cell and organelle membranes consist of a complex mixture of phospholipids (PLs) that determine their size, shape, and function. Phosphatidylcholine (PC) is the most abundant phospholipid in eukaryotic membranes, yet how cells sense and regulate its levels in vivo remains unclear. Here we show that PCYT1A, the rate-limiting enzyme of PC synthesis, is intranuclear and re-locates to the nuclear membrane in response to the need for membrane PL synthesis in yeast, fly, and mammalian cells. By aligning imaging with lipidomic analysis and data-driven modeling, we demonstrate that yeast PCYT1A membrane association correlates with membrane stored curvature elastic stress estimates. Furthermore, this process occurs inside the nucleus, although nuclear localization signal mutants can compensate for the loss of endogenous PCYT1A in yeast and in fly photoreceptors. These data suggest an ancient mechanism by which nucleoplasmic PCYT1A senses surface PL packing defects on the inner nuclear membrane to control PC homeostasis
Pilot-WINGS: An extended MUSE view of the structure of Abell 370
We investigate the strong-lensing cluster Abell 370 (A370) using a wide Integral Field Unit (IFU) spectroscopic mosaic from the Multi-Unit Spectroscopic Explorer (MUSE). IFU spectroscopy provides significant insight into the structure and mass content of galaxy clusters, yet IFU-based cluster studies focus almost exclusively on the central Einstein-radius region. Covering over 14 arcmin2, the new MUSE mosaic extends significantly beyond the A370 Einstein radius, providing, for the first time, a detailed look at the cluster outskirts. Combining these data with wide-field, multi-band Hubble Space Telescope (HST) imaging from the BUFFALO project, we analyse the distribution of objects within the cluster and along the line of sight. Identifying 416 cluster galaxies, we use kinematics to trace the radial mass profile of the halo, providing a mass estimate independent from the lens model. We also measure radially averaged properties of the cluster members, tracking their evolution as a function of infall. Thanks to the high spatial resolution of our data, we identify six cluster members acting as galaxy–galaxy lenses, which constrain localized mass distributions beyond the Einstein radius. Finally, taking advantage of MUSE’s 3D capabilities, we detect and analyse multiple spatially extended overdensities outside of the cluster that influence lensing-derived halo mass estimates. We stress that much of this work is only possible thanks to the robust, extended IFU coverage, highlighting its importance even in less optically dense cluster regions. Overall, this work showcases the power of combining HST + MUSE, and serves as the initial step towards a larger and wider program targeting several clusters
GDF15 Provides an Endocrine Signal of Nutritional Stress in Mice and Humans.
GDF15 is an established biomarker of cellular stress. The fact that it signals via a specific hindbrain receptor, GFRAL, and that mice lacking GDF15 manifest diet-induced obesity suggest that GDF15 may play a physiological role in energy balance. We performed experiments in humans, mice, and cells to determine if and how nutritional perturbations modify GDF15 expression. Circulating GDF15 levels manifest very modest changes in response to moderate caloric surpluses or deficits in mice or humans, differentiating it from classical intestinally derived satiety hormones and leptin. However, GDF15 levels do increase following sustained high-fat feeding or dietary amino acid imbalance in mice. We demonstrate that GDF15 expression is regulated by the integrated stress response and is induced in selected tissues in mice in these settings. Finally, we show that pharmacological GDF15 administration to mice can trigger conditioned taste aversion, suggesting that GDF15 may induce an aversive response to nutritional stress.This work and authors were funded by the NIHR Cambridge Biomedical Research Centre; NIHR Rare Disease Translational Research Collaboration; Medical Research Council [MC_UU_12012/2 and MRC_MC_UU_12012/3]; MRC Metabolic Diseases Unit [MRC_MC_UU_12012/5 and MRC_MC_UU_12012.1]; Wellcome Trust Strategic Award [100574/Z/12/Z and 100140]; Wellcome Trust [107064 , 095515/Z/11/Z , 098497/Z/12/Z, 106262/Z/14/Z and 106263/Z/14/Z]; British Heart Foundation [RG/12/13/29853]; Addenbrooke’s Charitable Trust / Evelyn Trust Cambridge Clinical Research Fellowship [16-69]
US Department of Agriculture: 2010-34323-21052; EFSD project grant and a Royal College of Surgeons Research Fellowship, Diabetes UK Harry Keen intermediate clinical fellowship (17/0005712). European Research Council, Bernard Wolfe Health Neuroscience Endowment, Experimental Medicine Training Initiative/AstraZeneca and Medimmune
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