High-resolution MHz time- and angle-resolved photoemission spectroscopy based on a tunable vacuum ultraviolet source

The time- and angle-resolved photoemission spectroscopy (trARPES) allows for direct mapping of the electronic band structure and its dynamic response on femtosecond timescales. Here, we present a new ARPES system, powered by a new fiber-based femtosecond light source in the vacuum ultraviolet range, accessing the complete first Brillouin zone for most materials. We present trARPES data on Au(111), polycrystalline Au, Bi2Se3, and TaTe2, demonstrating an energy resolution of 21 meV with a time resolution of <360 fs, at a high repetition rate of 1 MHz. The system is integrated with an extreme ultraviolet high harmonic generation beamline, enabling an excellent tunability of the time-bandwidth resolution.

Efficacy and findings of a blinded randomized reintroduction phase for the low FODMAP diet in Irritable Bowel Syndrome

BACKGROUND AND AIMS

The efficacy of a low fermentable oligo-, di-, monosaccharides and polyols (FODMAP) diet in Irritable Bowel Syndrome (IBS) is well established. After the elimination period, a reintroduction phase aims to identify triggers. We studied the impact of a blinded reintroduction using FODMAP-powders to objectively identify triggers and evaluated the effect on symptoms, quality of life (QoL), and psychosocial co-morbidities.

METHODS

Responders to a 6-week low-FODMAP diet, defined by a drop in IBS-symptom severity score (IBS-SSS) compared to baseline, entered a 9-week blinded randomized reintroduction phase with 6 FODMAP powders (fructans, fructose, galacto-oligosaccharides, lactose, mannitol, sorbitol) or control (glucose). A rise in IBS-SSS (≥50 points) defined a FODMAP-trigger. Patients completed daily symptom diaries and questionnaires for QoL and psychosocial co-morbidities.

RESULTS

In 117 recruited IBS patients, IBS-SSS improved significantly after the elimination period compared to baseline (150±116 vs 301±97, P < .0001, 80% responders). Symptom recurrence was triggered in 85% of the FODMAP powders, by an average of 2.5±2 FODMAPs/patient. The most prevalent triggers were fructans (56%) and mannitol (54%), followed by galacto-oligosaccharides, lactose, fructose, sorbitol, and glucose (respectively 35%, 28%, 27%, 23%, and 26%) with a significant increase in abdominal pain at day 1 for sorbitol/mannitol, day 2 for fructans/galacto-oligosaccharides and day 3 for lactose.

CONCLUSION

We confirmed the significant benefit of the low-FODMAP diet in tertiary care IBS. A blinded reintroduction revealed a personalized pattern of symptom recurrence, with fructans and mannitol as the most prevalent, and allows the most objective identification of individual FODMAP-triggers; Clinicaltrial.gov number: NCT04373304.

Third whole-brain radiation therapy for multiple brain metastases. Should it be considered in selected patients?

Whole brain reirradiation for the treatment of multiple brain metastases has shown promising results. However, concerns remain over the possible neurotoxic effects of the cumulative dose as well as the questionable radiosensitivity of recurrent metastases. A second reirradiation of the whole brain is ordinarily performed in our department for palliative purposes in patients presenting with multiple metastatic brain progression. For this study, an investigational third whole brain reirradiation has been administered to highly selected patients to obtain disease control and delay progression. Clinical outcomes and neurological toxicity were also evaluated.

Combined Transcriptomic and Metabolomic Approach Revealed a Relationship between Light Control, Photoprotective Pigments, and Lipid Biosynthesis in Olives

Olive possesses excellent nutritional and economic values for its main healthy products. Among them, a high content of antioxidant compounds, balanced during the ripening process, are produced under genetic and environmental control, resulting in high variability among cultivars. The genes involved in these complex pathways are mainly known, but despite many studies which indicated the key role of light quality and quantity for the synthesis of many metabolites in plants, limited information on these topics is available in olive. We carried out a targeted gene expression profiling in three olive cultivars, Cellina di Nardò, Ruveia, and Salella, which were selected for their contrasting oleic acid and phenolic content. The -omics combined approach revealed a direct correlation between a higher expression of the main flavonoid genes and the high content of these metabolites in 'Cellina di Nardò'. Furthermore, it confirmed the key role of FAD2-2 in the linoleic acid biosynthesis. More interestingly, in all the comparisons, a co-regulation of genes involved in photoperception and circadian clock machinery suggests a key role of light in orchestrating the regulation of these pathways in olive. Therefore, the identified genes in our analyses might represent a useful tool to support olive breeding, although further investigations are needed.

Light-Induced Metastable Hidden Skyrmion Phase in the Mott Insulator Cu2 OSeO3

The discovery of a novel long-lived metastable skyrmion phase in the multiferroic insulator Cu2 OSeO3 visualized with Lorentz transmission electron microscopy for magnetic fields below the equilibrium skyrmion pocket is reported. This phase can be accessed by exciting the sample non-adiabatically with near-infrared femtosecond laser pulses and cannot be reached by any conventional field-cooling protocol, referred as a hidden phase. From the strong wavelength dependence of the photocreation process and via spin-dynamics simulations, the magnetoelastic effect is identified as the most likely photocreation mechanism. This effect results in a transient modification of the magnetic free energy landscape extending the equilibrium skyrmion pocket to lower magnetic fields. The evolution of the photoinduced phase is monitored for over 15 min and no decay is found. Because such a time is much longer than the duration of any transient effect induced by a laser pulse in a material, it is assumed that the newly discovered skyrmion state is stable for practical purposes, thus breaking ground for a novel approach to control magnetic state on demand at ultrafast timescales and drastically reducing heat dissipation relevant for next-generation spintronic devices.

Generation and control of localized terahertz fields in photoemitted electron plasmas

Dense micron-sized electron plasmas, such as those generated upon irradiation of nanostructured metallic surfaces by intense femtosecond laser pulses, constitute a rich playground to study light-matter interactions, many-body phenomena, and out-of-equilibrium charge dynamics. Besides their fundamental interest, laser-induced plasmas hold great potential for the generation of localized terahertz radiation pulses. However, the underlying mechanisms ruling the formation and evolution of such plasmas are not yet well understood. Here, we develop a comprehensive microscopic theory to predictably describe the spatiotemporal dynamics of laser-pulse-induced plasmas. Through detailed analysis of electron emission, metal screening, and plasma cloud interactions, we investigate the spatial, temporal, and spectral characteristics of the so-generated terahertz fields, which can be extensively controlled through the metal morphology and the illumination conditions. We further describe the interaction with femtosecond electron beams to explain recent ultrafast electron microscopy experiments, whereby the position and temporal dependence of the observed electron acceleration permits assessing the associated terahertz field. Besides its potential application to the design of low-frequency light sources, our work contributes fundamental insight into the generation and dynamics of micron-scale electron plasmas and their interaction with ultrafast electron pulses.

Review article: Functional dyspepsia-a gastric disorder, a duodenal disorder or a combination of both?

BACKGROUND

Functional dyspepsia (FD) is one of the most frequent conditions in gastroenterological outpatient health care. Most recent research in FD has shifted its focus to duodenal pathophysiological mechanisms, although current treatments still focus mainly the stomach.

AIM

The aim of the study was to provide a comprehensive overview of the pathophysiology of FD focusing on a paradigm shift from gastric towards duodenal mechanisms.

METHODS

We conducted a literature search in PubMed for studies describing mechanisms that could possibly cause FD.

RESULTS

The pathophysiology of FD remains incompletely understood. Recent studies show that duodenal factors such as acid, bile salt exposure and eosinophil and mast cell activation correlate with symptom pattern and burden and can be associated with gastric sensorimotor dysfunction. The evolving data identify the duodenum an interesting target for new therapeutic approaches. Furthermore, the current first-line treatment, that is proton pump inhibitors, reduces duodenal low-grade inflammation and FD symptoms.

CONCLUSION

Future research for the treatment of FD should focus on the inhibition of duodenal mast cell activation, eosinophilia and loss of mucosal integrity.

Ultrafast Electron Microscopy of Nanoscale Charge Dynamics in Semiconductors

The ultrafast dynamics of charge carriers in solids plays a pivotal role in emerging optoelectronics, photonics, energy harvesting, and quantum technology applications. However, the investigation and direct visualization of such nonequilibrium phenomena remains as a long-standing challenge, owing to the nanometer-femtosecond spatiotemporal scales at which the charge carriers evolve. Here, we propose and demonstrate an interaction mechanism enabling nanoscale imaging of the femtosecond dynamics of charge carriers in solids. This imaging modality, which we name charge dynamics electron microscopy (CDEM), exploits the strong interaction of free-electron pulses with terahertz (THz) near fields produced by the moving charges in an ultrafast scanning transmission electron microscope. The measured free-electron energy at different spatiotemporal coordinates allows us to directly retrieve the THz near-field amplitude and phase, from which we reconstruct movies of the generated charges by comparison to microscopic theory. The CDEM technique thus allows us to investigate previously inaccessible spatiotemporal regimes of charge dynamics in solids, providing insight into the photo-Dember effect and showing oscillations of photogenerated electron-hole distributions inside a semiconductor. Our work facilitates the exploration of a wide range of previously inaccessible charge-transport phenomena in condensed matter using ultrafast electron microscopy.

Charge Dynamics Electron Microscopy: Nanoscale Imaging of Femtosecond Plasma Dynamics

Understanding and actively controlling the spatiotemporal dynamics of nonequilibrium electron clouds is fundamental for the design of light and electron sources, high-power electronic devices, and plasma-based applications. However, electron clouds evolve in a complex collective fashion on the nanometer and femtosecond scales, producing electromagnetic screening that renders them inaccessible to existing optical probes. Here, we solve the long-standing challenge of characterizing the evolution of electron clouds generated upon irradiation of metallic structures using an ultrafast transmission electron microscope to record the charged plasma dynamics. Our approach to charge dynamics electron microscopy (CDEM) is based on the simultaneous detection of electron-beam acceleration and broadening with nanometer/femtosecond resolution. By combining experimental results with comprehensive microscopic theory, we provide a deep understanding of this highly out-of-equilibrium regime, including previously inaccessible intricate microscopic mechanisms of electron emission, screening by the metal, and collective cloud dynamics. Beyond the present specific demonstration, the here-introduced CDEM technique grants us access to a wide range of nonequilibrium electrodynamic phenomena involving the ultrafast evolution of bound and free charges on the nanoscale.

Electric field writing and erasing of skyrmions in magnetoelectric Cu2OSeO3 with an ultralow energy barrier

Skyrmions are chiral magnetic textures with non-trivial topology, and due to their unique properties they are widely considered as promising information carriers in novel magnetic storage applications. While electric field writing/erasing and manipulation of skyrmions have been recently achieved, quantitative insights into the energetics of those phenomena remain scarce. Here, we report our in situ electric field writing/erasing of skyrmions in magnetoelectric helimagnet Cu₂OSeO₃ utilizing real-space and real-time Lorentz transmission electron macroscopy. Through the quantitavie analysis on our massive video data, we obtained a linear dependence of the number of skyrmions on the amplitude of the applied electric field, from which a local energy barried to write/erase skyrmions is estimated to be per skyrmion. Such an ultralow energy barrier implies the potential of precise control of skyrmions in future spintronics applications.

Ultrafast Transverse Modulation of Free Electrons by Interaction with Shaped Optical Fields

Spatiotemporal electron-beam shaping is a bold frontier of electron microscopy. Over the past decade, shaping methods evolved from static phase plates to low-speed electrostatic and magnetostatic displays. Recently, a swift change of paradigm utilizing light to control free electrons has emerged. Here, we experimentally demonstrate arbitrary transverse modulation of electron beams without complicated electron-optics elements or material nanostructures, but rather using shaped light beams. On-demand spatial modulation of electron wavepackets is obtained via inelastic interaction with transversely shaped ultrafast light fields controlled by an external spatial light modulator. We illustrate this method for the cases of Hermite-Gaussian and Laguerre-Gaussian modulation and discuss their use in enhancing microscope sensitivity. Our approach dramatically widens the range of patterns that can be imprinted on the electron profile and greatly facilitates tailored electron-beam shaping.

Systemic GDF11 replenishment ignites myocardial injury through diminishing anti-apoptotic activity of cardiac progenitor cells

Background

Tissue damage due to acute myocardial infarction is caused by both the ischemic insult and subsequent reperfusion injury (I/R). Restoration of coronary blood flow accelerates cardiomyocyte death, a phenomenon referred to as reperfusion injury, the extent of which is partly modulated by cardiac progenitor cells (CPC). Development of novel therapies to reduce infarct size, the main determinant of outcome, represent a huge unmet medical need (1). Systemic levels of growth differentiation factor 11 (GDF11), a TGF-β superfamily member that shares 90% homology with myostatin, decline with age, and GDF11 replenishment by heterochronic parabiosis or systemic recombinant GDF11 (rGDF11) delivery was postulated to have rejuvenating effects (2).

Purpose

We aimed to probe the effects of systemic GDF11 replenishment on I/R injury and deepen insights into the molecular mechanisms involved.

Methods

We designed a vehicle-controlled study in which young (3–4 months) and old (22–24 months) C57Bl/6 mice were randomly assigned to either daily systemic rGDF11 or control treatment over 30 days before myocardial I/R injury was induced. Dissected hearts were subjected to in-depth profiling followed by IPA-guided -omics to identify key regulatory mechanisms. Finally, in vitro experiments on human CPCs and HL-1 cardiomyocytes were performed.

Results

Myocardial Gdf11 expression declined with age, whereas myostatin (Mstn) showed an opposing expression pattern (Fig. 1A), a trend similarly observed upon I/R (Fig. 1B). Surprisingly, after the 30-day study period (Fig. 1C), young and aged rGDF11-treated mice showed higher I/R-induced infarct size and serum cardiac troponin I levels than controls, despite comparable areas at risk (Fig. 1D). Importantly, while proxies of necroptosis/pyroptosis remained unchanged, rGDF11-treated animals showed reduced cardiomyocyte viability irrespective of their age (Fig. 2A). Targeted transcriptomics applied on cardiac tissues of both groups identified the CPC-marker Nkx2–5 to be differentially regulated (Fig. 2B-C), an expression pattern validated in an independent cohort at both mRNA and protein levels (Fig. 2D). In the adult myocardium, the expression of both Nkx2–5 and its cofactor Gata4 is mainly confined to CPCs; indeed, similar reductions in Nkx2–5 and Gata4 expression were observed in CPCs exposed to rGDF11 (Fig. 2E) which coincided with accelerated cardiomyocyte death if cultured in conditioned media obtained from CPCs treated with rGDF11 (Fig. 2F), pointing toward a paracrine signalling pathway.

Conclusions

Myocardial expression of GDF11 declines with age, and is blunted upon I/R injury, thereby opposing the expression pattern of myostatin. Surprisingly, however, systemic GDF11 replenishment by rGDF11 supplementation enhances rather than reduces myocardial infarct size through augmented apoptosis, a phenomenon mediated by diminished cardioprotective function of CPCs.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): Foundation for Cardiovascular Research – Zurich Heart House

Nuclear Excitation by Free Muon Capture

Efficient excitation of nuclei via exchange of a real or virtual photon has a fundamental importance for nuclear science and technology development. Here, we present a mechanism of nuclear excitation based on the capture of a free muon into the atomic orbits (NEμC). The cross section of such a proposed process is evaluated using the Feshbach projection operator formalism and compared to other known excitation phenomena, i.e., photoexcitation and nuclear excitation by electron capture (NEEC), showing up to 10 orders of magnitude increase in cross section. NEμC is particularly interesting for MeV excitations that become accessible thanks to the stronger binding of muons to the nucleus. The binding energies of muonic atoms have been calculated introducing a state of the art modification to the Flexible Atomic Code. An analysis of experimental scenarios in the context of modern muon production facilities shows that the effect can be detectable for selected isotopes. The total probability of NEμC is predicted to be P≈1×10^{-6} per incident muon in a beam-based scenario. Given the high transition energy provided by muons, NEμC can have important consequences for isomer feeding and particle-induced fission.

Nuclear Excitation by Electron Capture in Excited Ions

A nuclear excitation following the capture of an electron in an empty orbital has been recently observed for the first time. So far, the evaluation of the cross section of the process has been carried out widely using the assumption that the ion is in its electronic ground state prior to the capture. We show that by lifting this restriction new capture channels emerge resulting in a boost of more than three orders of magnitude to the electron capture resonance strength.

Dynamical Control of Nuclear Isomer Depletion via Electron Vortex Beams

Some nuclear isomers are known to store a large amount of energy over long periods of time, with a very high energy-to-mass ratio. Here, we describe a protocol to achieve the external control of the isomeric nuclear decay by using electron vortex beams whose wave function has been especially designed and reshaped on demand. Recombination of these electrons into the isomer's atomic shell can lead to the controlled release of the stored nuclear energy. On the example of ^{93m}Mo, we show theoretically that the use of tailored electron vortex beams increases the depletion by 4 orders of magnitude compared to the spontaneous nuclear decay of the isomer. Furthermore, specific orbitals can sustain an enhancement of the recombination cross section for vortex electron beams by as much as 6 orders of magnitude, providing a handle for manipulating the capture mechanism. These findings open new prospects for controlling the interplay between atomic and nuclear degrees of freedom, with potential energy-related and high-energy radiation source applications.

Direct Visualisation of Skyrmion Lattice Defect Alignment at Grain Boundaries

We present a method to directly visualise a statistical analysis of skyrmion defect alignment at grain boundaries in the skyrmion host [Formula: see text]OSeO3. Using Lorentz transmission electron microscopy, we collected large data sets with several hundreds of frames containing skyrmion lattices with grain boundaries in them. To address the behaviour of strings of dislocations in these grain boundaries, we developed an algorithm to automatically extract and classify strings of dislocations separating the grains. This way we circumvent the problem of having to create configurations with well-defined relative grain orientations by performing a statistical analysis on a dynamically rearranging image sequence. With this statistical method, we are able to experimentally extract the relationship between grain boundary alignment and defect spacing and find an agreement with geometric expectations. The algorithms used can be extended to other types of lattices such as Abrikosov lattices or colloidal systems in optical microscopy.

An electron walks into a quantum bar…

[Figure: see text].

PCSK9 is associated with mortality in patients with septic shock: data from the ALBIOS study

BACKGROUND

Pro-protein convertase subtilisin/kexin 9 (PCSK9) is a proenzyme primarily known to regulate low-density lipoprotein receptor re-uptake on hepatocytes. Whether PCSK9 can concurrently trigger inflammation or not remains unclear. Here, we investigated the potential association between circulating levels of PCSK9 and mortality in patients with severe sepsis or septic shock.

METHODS

Plasma PCSK9 levels at days 1, 2 and 7 were measured in 958 patients with severe sepsis or septic shock previously enrolled in the Albumin Italian Outcome Sepsis (ALBIOS) trial. Correlations between levels of PCSK9 and pentraxin 3 (PTX3), a biomarker of disease severity, were evaluated with ranked Spearman's coefficients. Cox proportional hazards models were used to assess the association of PCSK9 levels at day 1 with 28- and 90-day mortality.

RESULTS

Median plasma PCSK9 levels were 278 [182-452] ng mL^-1 on day 1. PCSK9 correlated positively with PTX3 at the three time-points, and patients with septic shock within the first quartile of PCSK9 showed higher levels of PTX3. Similar mortality rates were observed in patients with severe sepsis across PCSK9 quartiles. Patients with septic shock with lower PCSK9 levels on day 1 (within the first quartile) showed the highest 28- and 90-day mortality rate as compared to other quartiles.

CONCLUSION

In our sub-analysis of the ALBIOS trial, we found that patients with septic shock presenting with lower plasma PCSK9 levels experienced higher mortality rate. Further studies are warranted to better evaluate the pathophysiological role of PCSK9 in sepsis.

Publisher Correction: Melting of a skyrmion lattice to a skyrmion liquid via a hexatic phase

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Melting of a skyrmion lattice to a skyrmion liquid via a hexatic phase

The phase transition most commonly observed is probably melting, a transition from ordered crystalline solids to disordered isotropic liquids. In three dimensions, melting is a single, first-order phase transition. In two-dimensional systems, however, theory predicts a general scenario of two continuous phase transitions separated by an intermediate, oriented liquid state, the so-called hexatic phase with short-range translational and quasi-long-range orientational orders. Such hexatic phases occur in colloidal systems, Wigner solids and liquid crystals, all composed of real-matter particles. In contrast, skyrmions are countable soliton configurations with non-trivial topology and these quasi-particles can form two-dimensional lattices. Here we show, by direct imaging with cryo-Lorentz transmission electron microscopy, that magnetic field variations can tune the phase of the skyrmion ensembles in Cu₂OSeO₃ from a two-dimensional solid through the long-speculated skyrmion hexatic phase to a liquid. The local spin order persists throughout the process. Remarkably, our quantitative analysis demonstrates that the aforementioned topological-defect-induced crystal melting scenario well describes the observed phase transitions.

Analysis of Postprandial Symptom Patterns in Subgroups of Patients With Rome III or Rome IV Functional Dyspepsia

BACKGROUND & AIMS

Among patients with functional dyspepsia (FD), there is overlap in symptoms between those in the Rome III subgroups of postprandial distress syndrome (PDS) and those with epigastric pain syndrome (EPS). The Rome IV consensus proposed to incorporate all patients with postprandial symptoms into the PDS group. We aimed to evaluate the assessment of meal-related dyspepsia symptoms in patients with FD according to the Rome III vs Rome IV subdivisions.

METHODS

Consecutive patients with FD referred for a gastric emptying test (n = 96) were asked to fill out the Rome III gastroduodenal questionnaire, with questions on meal-related occurrence. Study participants underwent a gastric emptying breath test, during which the intensity of dyspeptic symptoms (fullness, bloating, belching, nausea, epigastric pain, and burning) was scored before and up to 4 hours after a meal. We analyzed the association between the Rome subdivision and symptom severity and pattern during the breath test.

RESULTS

According to Rome III, 10% had EPS alone, 29% PDS alone, and 61% overlapping EPS and PDS. The frequency of the symptoms reported in the Rome questionnaire associated with the intensity of the symptoms during the breath test in the PDS group and in the groups with PDS and EPS overlap, but not in the group with EPS. We adapted the definition of the PDS subgroup to include patients with meal-related non-PDS symptoms (Rome IV); this reduced the proportion of patients with overlap of EPS and PDS symptoms from 61% to 18% and in this group the association of symptoms with the meal was reduced.

CONCLUSIONS

In an analysis of patients with FD, a meal induced or exacerbated symptoms in most patients. The Rome IV criteria for PDS reduce the proportions categorized as having both PDS and EPS and identify a patient group whose symptoms are associated with the meals. University hospital of Leuven study no: S55426.

Current and emerging therapeutic options for the management of functional dyspepsia

Introduction: Functional Dyspepsia (FD), defined as chronic symptoms originating from the gastroduodenal region in absence of readily identifiable organic disease, is one of the most common gastrointestinal disorders. FD is divided into two subgroups: Post-Prandial Distress Syndrome (PDS) or meal-related FD, characterized by postprandial fullness and early satiation, and Epigastric Pain Syndrome (EPS) or meal-unrelated FD, characterized by epigastric pain and burning.Areas covered: This review summarizes the existing and off-label therapeutic options for FD.Expert opinion: The identification of mechanisms, the Rome IV classification, the reduction of PDS/EPS overlap and pictograms for symptom identification allow a better diagnosis and a more targeted treatment choice. Acotiamide, a first-in-class prokinetic agent available only in Japan and India, is the only agent of proven efficacy for FD, but clinicians use acid-suppressive therapy, prokinetics, neuromodulators and herbal therapies for treating FD symptoms. New emerging targets are duodenal low-grade inflammation with eosinophils and duodenal or other modified luminal microbiota.

Association Study of the 5'UTR Intron of the FAD2-2 Gene With Oleic and Linoleic Acid Content in Olea europaea L

Cultivated olive (Olea europaea L. subsp. europaea var. europaea) is the most ancient and spread tree crop in the Mediterranean basin. An important quality trait for the extra virgin olive oil is the fatty acid composition. In particular, a high content of oleic acid and low of linoleic, linolenic, and palmitic acid is considered very relevant in the health properties of the olive oil. The oleate desaturase enzyme encoding-gene (FAD2-2) is the main responsible for the linoleic acid content in the olive fruit mesocarp and, therefore, in the olive oil revealing to be the most important candidate gene for the linoleic acid biosynthesis. In this study, an in silico and structural analysis of the 5'UTR intron of the FAD2-2 gene was conducted with the aim to explore the natural sequence variability and its role in the gene expression regulation. In order to identify functional allele variants, the 5'UTR intron was isolated and partially sequenced in 97 olive cultivars. The sequence analysis allowed to find a 117-bp insertion including two long duplications never found before in FAD2-2 genes in olive and the existence of many intron-mediated enhancement (IME) elements. The sequence polymorphism analysis led to detect 39 SNPs. The candidate gene association study conducted for oleic and linoleic acids content revealed seven SNPs and one indel significantly associated able to explain a phenotypic variation ranging from 7% to 16% among the years. Our study highlighted new structural variants within the FAD2-2 gene in olive, putatively involved in the regulation mechanisms of gene expression associated with the variation of the content of oleic and linoleic acid.

Identification of miRNAs involved in fruit ripening by deep sequencing of Olea europaea L. transcriptome

BACKGROUND

The ripening process of olive fruits is associated with chemical and/or enzymatic specific transformations, making them particularly attractive to animals and humans. In olive drupes, including 'Cassanese' ones, ripening is usually accompanied by progressive chromatic change, resulting in a final red-brown colourization of both epidermis and mesocarp. This event has an exception in the 'Leucocarpa', in which we observed the destabilization in the equilibrium between the chlorophyll metabolism and that of the other pigments, particularly the anthocyanins, whose switch-off during maturation promotes the white colouration of the fruits. Recently, transcription profiling of 'Leucocarpa' and 'Cassanese' olives along ripening, performed through an Illumina RNA-seq approach, has provided useful insights on genes functions involved in fruit maturation such as those related to the biosynthesis of flavonoids and anthocyanins.

METHODOLOGY

To assess expression alterations of genes involved in flavonoids and anthocyanins biosynthetic pathways during ripening, possibly caused by small nuclear RNA (snRNA) in olive drupes, snRNA libraries from 'Leucocarpa' and 'Cassanese' were constructed with RNAs extracted at 100 and 130 Days After Flowering (DAF) and sequenced by an Illumina approach. 130 conserved microRNAs (miRNA) in the Viridiplantae belonging to 14 miRNA families were identified. Regarding the 130 conserved miRNAs, approximately the 48% were identified in all libraries, 5 and 18 miRNAs were shared between the "Cassanese" (C100, C130) and "Leucocarpa" (L100, L130) libraries, respectively.

CONCLUSION

For the remaining reads not-matching with known miRNAs in the Viridiplantae, we combined secondary structure and minimum free energy to discover novel olive miRNAs. Based on these analyses, 492 sequences were considered as putative novel miRNAs. The putative target genes of identified miRNA were computationally predicted by alignment with the olive drupe transcripts obtained from the same samples. A total of 218 transcripts were predicted as targets of 130 known and 492 putative novel miRNAs. Interestingly, some identified target genes are involved in negative regulation of anthocyanin metabolic process. Quantification of the expression pattern of three miRNA and their target transcripts by qRT-PCR assay confirmed the results of Illumina sequencing.

Lymph node assessment in colorectal cancer surgery: laparoscopic versus open techniques

AIM

The aim of our study is to compare the outcomes of laparoscopic resection (LR) and open resection (OR) for colorectal cancer surgery evaluating lymph node assessment. It may be important to remove and examine an adequate number of lymph nodes because a more extensive nodal resection has been associated to higher survival rate and lower recurrences.

PATIENTS AND METHODS

150 patients (74 females and 76 males) with colorectal cancer were enrolled and analyzed from January 2006 to March 2010 in our Unit. 100 procedures were performed with traditional laparotomy and 50 procedures laparoscopically. A strict follow-up was scheduled every 1-3-6 months after surgery and, therefore, every year.

RESULTS

Laparoscopic techniques require a longer operating time. 2484 total lymph nodes examined with a mean of 16,56 removed per resection in all procedures. 1632 lymph nodes were removed during open procedures and 852 removed during laparoscopy. The scheduled follow-up demonstrated that local recurrence and distant metastasis presented with no significant differences between two groups and overall survival and disease-free survival were assessed over 5 year in 80% of patients.

CONCLUSIONS

According to our experience, laparoscopic colorectal surgery is safe and feasible, with better short-term outcomes and oncological adequacy comparable to open approach.

Ultrafast generation and control of an electron vortex beam via chiral plasmonic near fields

Vortex-carrying matter waves, such as chiral electron beams, are of significant interest in both applied and fundamental science. Continuous-wave electron vortex beams are commonly prepared via passive phase masks imprinting a transverse phase modulation on the electron's wavefunction. Here, we show that femtosecond chiral plasmonic near fields enable the generation and dynamic control on the ultrafast timescale of an electron vortex beam. The vortex structure of the resulting electron wavepacket is probed in both real and reciprocal space using ultrafast transmission electron microscopy. This method offers a high degree of scalability to small length scales and a highly efficient manipulation of the electron vorticity with attosecond precision. Besides the direct implications in the investigation of nanoscale ultrafast processes in which chirality plays a major role, we further discuss the perspectives of using this technique to shape the wavefunction of charged composite particles, such as protons, and how it can be used to probe their internal structure.

Holographic imaging of electromagnetic fields via electron-light quantum interference

Holography relies on the interference between a known reference and a signal of interest to reconstruct both the amplitude and the phase of that signal. With electrons, the extension of holography to the ultrafast time domain remains a challenge, although it would yield the highest possible combined spatiotemporal resolution. Here, we show that holograms of local electromagnetic fields can be obtained with combined attosecond/nanometer resolution in an ultrafast transmission electron microscope (UEM). Unlike conventional holography, where signal and reference are spatially separated and then recombined to interfere, our method relies on electromagnetic fields to split an electron wave function in a quantum coherent superposition of different energy states. In the image plane, spatial modulation of the electron energy distribution reflects the phase relation between reference and signal fields. Beyond imaging applications, this approach allows implementing quantum measurements in parallel, providing an efficient and versatile tool for electron quantum optics.

Local photo-mechanical stiffness revealed in gold nanoparticles supracrystals by ultrafast small-angle electron diffraction

We demonstrate that highly ordered two-dimensional crystals of ligand-capped gold nanoparticles display a local photo-mechanical stiffness as high as that of solids such as graphite. In out-of-equilibrium electron diffraction experiments, a strong temperature jump is induced in a thin film with a femtosecond laser pulse. The initial electronic excitation transfers energy to the underlying structural degrees of freedom, with a rate generally proportional to the stiffness of the material. Using femtosecond small-angle electron diffraction, we observe the temporal evolution of the diffraction feature associated with the nearest-neighbor nanoparticle distance. The Debye-Waller decay for the octanethiol-capped nanoparticle supracrystal, in particular, is found to be unexpectedly fast, almost as fast as the stiffest solid known and observed by the same technique, i.e., graphite. Our observations unravel that local stiffness in a dense supramolecular assembly can be created by van der Waals interactions up to a level comparable to crystalline systems characterized by covalent bonding.

Prevalence and impact of self-reported irritable bowel symptoms in the general population

Background and aims

The symptom-based diagnostic criteria for irritable bowel syndrome (IBS) have recently been revised in the Rome IV consensus. On the other hand, with rising public awareness of IBS, self-diagnosis and self-management is also increasing. We compared the prevalence and impact of Rome IV-based IBS vs self-diagnosed IBS in the general population.

Methods

An internet panel filled out an online survey on bowel symptoms and their impact on health care utilization and daily activities.

Results

A representative internet panel of 1012 individuals completed the online survey. Bowel symptoms were present in 68.6% of the population. Of these, 21% consulted a physician for these symptoms in the last year and 42% earlier. Rome IV IBS criteria were fulfilled by 5.5%, and these were younger and more likely to be female. In this subset, 37% had consulted a physician for IBS symptoms in the preceding year and 29% had done so earlier. A colonoscopy had been performed in 22%. Based on a brief description, 17.6% of the population self-identified as suffering from IBS (p < 0.001 compared to Rome IV IBS prevalence), and these were more likely to be female. Concordance with the Rome IV criteria was only 25%, but except for a lower reporting of pain, the symptom pattern, severity, impact on daily life, inability to work and health care utilization were similar to the Rome IV group. A total of 134 days of absence from work were attributed to bowel symptoms in those self-reporting with IBS.

Conclusion

In the general population, bowel symptoms are highly prevalent, and the self-reported "IBS" is three times more prevalent than according to Rome IV criteria. Self-reported IBS is associated with a similar impact on health care utilization and quality of life but a higher impact on absence from work.

Direct observation of photo-mechanical stiffness in alkanethiol-capped gold nanoparticles supracrystals by ultrafast small-angle electron diffraction

We demonstrate that ultrastiff bonding between nanoparticles can be engineered by ad hoc assemblies of ligands, reaching strengths comparable to that of strong covalent bonds. Our observation relies on femtosecond small-angle electron diffraction.

Serum levels of osteopontin predict diabetes remission after bariatric surgery

AIM

Bariatric surgery has been shown to effectively improve glycaemic control in morbidly obese subjects. However, the molecular bases of this association are still elusive and may act independently of weight loss. Here, our retrospective study has investigated the inflammatory molecule osteopontin (OPN) as a potential predictor of type 2 diabetes mellitus (T2DM) remission.

METHODS

Baseline serum levels of OPN were analyzed in 41 T2DM patients who underwent bariatric surgery. Anthropometric measures and biochemical variables, including insulin sensitivity indices (HOMA2), were assessed at baseline and at 1 and 3 years after surgery.

RESULTS

At baseline, patients who experienced T2DM remission had increased waist circumference, body weight and BMI, and higher serum OPN, compared with non-remitters. Patients with and without T2DM remission improved their lipid and glucose profiles, although insulin resistance indices were only improved in the T2DM remission group. In the overall cohort of both T2DM remission and non-remission patients, baseline circulating levels of OPN significantly correlated with reductions of body weight and BMI over time, and insulin sensitivity improved as well. However, only the HOMA2-%S remained independently associated with serum OPN on multivariate linear regression analysis (B: 0.227, 95% CI: 0.067-0.387, β = 0.831; P = 0.010). Baseline values of OPN predicted 3-year T2DM remission independently of body weight loss, lower BMI and duration of diabetes (OR: 1.046, 95% CI: 1.004-1.090; P = 0.033).

CONCLUSION

Although larger studies are still needed to confirm our preliminary results, pre-operative OPN serum levels might be useful for predicting 3-year T2DM remission independently of weight loss in patients undergoing bariatric surgery.

In Situ Electric Field Skyrmion Creation in Magnetoelectric Cu2OSeO3

Exploiting additional degrees of freedom in solid-state materials may be the most-promising solution when approaching the quantum limit of Moore's law for the conventional electronic industry. Recently discovered topologically nontrivial spin textures, skyrmions, are outstanding among such possibilities. However, the controlled creation of skyrmions, especially by electric means, remains a pivotal challenge in technological applications. Here, we report that skyrmions can be created locally via electric field in the magnetoelectric helimagnet Cu₂OSeO₃. Using Lorentz transmission electron microscopy, we successfully write skyrmions in situ from a helical-spin background. Our discovery is highly coveted because it implies that skyrmionics can be integrated into modern field effect transistor based electronic technology, in which very low energy dissipation can be achieved and, hence, realize a large step forward toward its practical applications.

High serum levels of C-reactive protein (CRP) predict beneficial decrease of visceral fat in obese females after sleeve gastrectomy

BACKGROUND & AIMS

Gender-related differences represent an emerging investigation field to better understand obesity heterogeneity and paradoxically associated cardiovascular (CV) risk. Here, we investigated if high-sensitivity C-reactive protein (hs-CRP) might differently affect adiposity and predict the clinical response to bariatric surgery in obese males and females.

METHODS AND RESULTS

In 110 morbidly obese patients undergoing laparoscopic sleeve gastrectomy, hs-CRP as well as anthropometric assessment of adiposity, completed by electric bioimpedance and ultrasonography quantification of visceral fat area (VFA), were measured before and one year after surgery. As compared to males, obese female showed less severe overweight and prevalent subcutaneous fat deposition, but higher circulating hs-CRP. In obese females, hs-CRP was associated with VFA at baseline, independently of body mass index (BMI) and visceral adiposity index (OR 1.022 [95% CI 1.001-1.044]; p = 0.039). Based on decreases and increases in hs-CRP levels after surgery, two distinct subgroups of females were identified. Post-surgery decreases in hs-CRP was predominantly observed in patients with higher baseline levels of hs-CRP and associated with greater reduction of weight, BMI, fat and lean mass, VFA and visceral to subcutaneous fat ratio. Finally, we observed that high baseline values of hs-CRP were able to predict VFA reduction one-year after surgery, independently of BMI and visceral adiposity index (VAI) loss (OR 1.031 [95% CI 1.009-1.053]; p = 0.005).

CONCLUSION

In obese females, hs-CRP levels might be a promising biomarker of visceral fat amount and dysfunction, in addition to predict the effectiveness of bariatric surgery in terms of loss of VFA one-year after surgery.

The effect of sildenafil on gastric motility and satiation in healthy controls

Sildenafil induces relaxation of smooth muscle cells by blocking PDE5. Dyspepsia is one of sildenafil's most frequently reported adverse events, suggesting its effect on gastric motility. Our aim was to study the effect of sildenafil on gastric accommodation (GA) and gastric emptying (GE) in healthy volunteers (HVs).

Methods

Sildenafil (50 mg) or placebo was randomly administered to 16 blinded HVs. After a manometry probe and an infusion catheter were positioned in the proximal stomach, the intragastric pressure (IGP) was measured before and during nutrient drink infusion (ND, 60 ml/min). HVs were asked to score their hunger, satiation and six epigastric symptoms at five-minute intervals. The experiment ended when the HVs scored maximal satiation during ND infusion at one-minute intervals. To assess GE, breath samples were collected every 15 minutes for six hours after the meal (244 kcal).

Results

ND infusion induced a drop in proximal stomach IGP, which was suppressed by sildenafil (average area under the curve for sildenafil: -33.6 ± 8.8 mmHg; placebo: -60.8 ± 11.3 mmHg, p = 0.005). Sildenafil-treated volunteers reached earlier maximal satiation compared to placebo (678 ± 70 ml vs. 836 ± 82.6 ml, p = 0.019). Finally, GE was significantly slower after sildenafil (90.6 ± 5.9 min vs. 76.6 ± 7.1 min, p = 0.04).

Conclusion

Sildenafil inhibits GA, leading to significantly decreased nutrient tolerance, and slightly delays the GE rate in humans.

Laser-Induced Skyrmion Writing and Erasing in an Ultrafast Cryo-Lorentz Transmission Electron Microscope

We demonstrate that light-induced heat pulses of different duration and energy can write Skyrmions in a broad range of temperatures and magnetic field in FeGe. Using a combination of camera-rate and pump-probe cryo-Lorentz transmission electron microscopy, we directly resolve the spatiotemporal evolution of the magnetization ensuing optical excitation. The Skyrmion lattice was found to maintain its structural properties during the laser-induced demagnetization, and its recovery to the initial state happened in the sub-μs to μs range, depending on the cooling rate of the system.

The superstatistical nature and interoccurrence time of atmospheric mercury concentration fluctuations

The probability density function (PDF) of the time intervals between subsequent extreme events in atmospheric Hg⁰ concentration data series from different latitudes has been investigated. The Hg⁰ dynamic possesses a long-term memory autocorrelation function. Above a fixed threshold Q in the data, the PDFs of the interoccurrence time of the Hg⁰ data are well described by a Tsallis q-Exponential function. This PDF behavior has been explained in the framework of superstatistics, where the competition between multiple mesoscopic processes affects the macroscopic dynamics. An extensive parameter μ, encompassing all possible fluctuations related to mesoscopic phenomena, has been identified. It follows a χ ²-distribution, indicative of the superstatistical nature of the overall process. Shuffling the data series destroys the long-term memory, the distributions become independent of Q, and the PDFs collapse on to the same exponential distribution. The possible central role of atmospheric turbulence on extreme events in the Hg⁰ data is highlighted.

Omics approaches on fresh-cut lettuce reveal global molecular responses to sodium hypochlorite and peracetic acid treatment

BACKGROUND

Lettuce is a leafy vegetable that is extensively commercialized as a ready-to-eat product because of its widespread use in human nutrition as salad. It is well known that washing treatments can severely affect the quality and shelf-life of ready-to-eat vegetables. The study presented here evaluated the effect of two washing procedures on fresh-cut lettuce during storage.

RESULTS

An omics approach was applied to reveal global changes at molecular level induced by peracetic acid washing in comparison with sodium hypochlorite treatment. Microbiological analyses were also performed to quantify total bacterial abundance and composition. The study revealed wide metabolic alterations induced by the two sanitizers. In particular, transcriptomic and proteomic analyses pointed out a number of transcripts and proteins differentially accumulated in response to peracetic acid washing, mainly occurring on the first day of storage. In parallel, different microbiota composition and significant reduction in total bacterial load following washing were also observed.

CONCLUSION

The results provide useful information for the fresh-cut industry to select an appropriate washing procedure preserving fresh-like attributes as much as possible during storage of the end product. Molecular evidence indicated peracetic acid to be a valid alternative to sodium hypochlorite as sanitizer solution. © 2017 Society of Chemical Industry.

The effect of mirtazapine on gastric accommodation, gastric sensitivity to distention, and nutrient tolerance in healthy subjects

BACKGROUND

Disturbances of gastric motor function of functional dyspepsia (FD) have been implicated in the pathogenesis of the symptoms, and hence, motility modifying agents are considered for its treatment. Mirtazapine was recently shown to improve symptoms and increase nutrient tolerance in FD patients with weight loss. We aim to evaluate the effect of mirtazapine on gastric sensorimotor function in healthy volunteers (HV).

METHODS

Thirty-one HV underwent an intragastric pressure (IGP) and barostat measurements on separate days before and after 3 weeks of placebo or mirtazapine (15 mg). Gastric compliance, sensitivity and accommodation (GA) measured by the barostat. GA was quantitated as the difference (delta) in intra-balloon volume before and after ingestion of 200 mL of a nutrient drink (ND). GA measured by IGP was quantitated as the drop of IGP from baseline during the intragastric infusion of ND until maximal satiation.

KEY RESULTS

Mirtazapine significantly increased the bodyweight of subjects (67.8±3.7 to 69.1±3.7 kg; P=.01). Barostat results showed no effect on gastric compliance, sensitivity, and GA. Nutrient tolerance was not affected after treatment (1170±129.4 vs 1104±133.6 kcal; P=.4), and mirtazapine was associated with lower symptom ratings. The IGP drop during meal ingestion was significantly suppressed (area under the curve: -43.3±4.5 mm Hg vs -28.9±3.1 mm Hg; P=.005).

CONCLUSIONS & INFERENCES

In HVs, the occurrence of weight gain and decreased meal-induced symptoms in spite of a suppressed meal-induced IGP drop, point towards a central mode of action. Mirtazapine does not display changes in gastric sensorimotor function that could explain its beneficial effects on symptoms and nutrient tolerance in FD.