Laparotomy causes loss of peritoneal mesothelium prevented by humidified CO2 insufflation, in rats

Introduction: Avoiding tissue desiccation is a common recommendation to reduce postoperative complications following open abdominal surgery, although difficult to achieve delicately without damaging the peritoneal mesothelium. Insufflation of humidified-warm CO2 into the abdomen during open abdominal surgery is proposed as an invisible, effortless way to prevent desiccation. We hypothesized that desiccation during open abdominal surgery would cause loss of peritoneal mesothelium that would be prevented by insufflation of humidified-warm CO2. Methods: Nine Wistar rats were assigned to 1 h of anesthesia only, laparotomy only, or laparotomy with insufflation of humidified-warm CO2. Twelve hours after treatment, rats were euthanized and tissue samples were excised. Scanning electron microscopy (SEM) and light microscopy (LM) images of visceral and parietal peritoneum were scored by two independent, blinded examiners for loss of mesothelium and other indications of inflammation, including measurement of apoptosis by detection of DNA cleavage. Results: Loss of peritoneal mesothelium was found in peritoneum exposed to laparotomy only (SEM: P = 0.002; LM: P = 0.01), and mesothelial loss was reduced by humidified-warm CO2 (SEM: P \u3c 0.001; LM P = 0.004). Similarly, DNA cleavage was significantly higher on the peritoneal surface following laparotomy only, compared with anesthesia only (P = 0.0055) and laparotomy with humidified-warm CO2 insufflation (P = 0.0003). Conclusions: In a rat model, exposing the peritoneal mesothelial to conditions that replicate minimum recommended air flow within an operating room causes inadvertent loss of mesothelium and signs of inflammation that can be prevented by insufflating humidified-warm CO2 into the open abdominal cavity

Photoexcited triplet states of twisted acenes investigated by Electron Paramagnetic Resonance

Twisting of the acene backbone out of planarity in twisted acenes leads to a variation in their optical and electronic properties. The effect of increasing twist angles on the properties of the photoexcited triplet states of a series of anthracene-based helically tethered twisted acenes is investigated here by Electron Paramagnetic Resonance (EPR) spectroscopy. Increasing signal intensities with increasing twist angles indicate increased intersystem crossing efficiencies for the twisted molecules compared to the untethered reference compound. Variations in the electron spin polarisation observed in the transient EPR spectra, in particular for the compound with the shortest tether, imply changes in the sublevel population kinetics depending on molecular geometry. Changes in the zero-field splitting parameters and in the proton hyperfine couplings for compounds with short tethers and therefore higher twist angles point towards a slight redistribution of the spin density compared to the parent compound. The experimental results can be explained by considering both an increase in twist angle and a related decrease in the dihedral angle between the phenyl side groups and the acene core. The observation of a clear excitation-wavelength dependence suggests preferential excitation of different molecular conformations, with conformers characterised by higher twist angles selected at higher wavelengths

Mediation of nitrogen by post-disturbance shelf communities experiencing organic matter enrichment

Microbes and benthic macro-invertebrates interact in sediments to play a major role in the biogeochemical cycling of organic matter, but the extent to which their contributions are modified following natural and anthropogenic changes has received little attention. Here, we investigate how nitrogen transformations, ascertained from changes in archaeal and bacterial N-cycling microbes and water macronutrient concentrations ([NH4–N], [NO2–N], [NO3–N]), in sand and sandy mud sediments differ when macrofaunal communities that have previously experienced contrasting levels of chronic fishing disturbance are exposed to organic matter enrichment. We find that differences in macrofaunal community structure related to differences in fishing activity affect the capacity of the macrofauna to mediate microbial nitrogen cycling in sand, but not in sandy mud environments. Whilst we found no evidence for a change in ammonia oxidiser community structure, we did find an increase in archaeal and bacterial denitrifier (AnirKa, nirS) and anammox (hzo) transcripts in macrofaunal communities characterized by higher ratios of suspension to deposit feeders, and a lower density but higher biomass of sediment-reworking fauna. Our findings suggest that nitrogen transformation in shelf sandy sediments is dependent on the stimulation of specific nitrogen cycling pathways that are associated with differences in the composition and context-dependent expression of the functional traits that belong to the resident bioturbating macrofauna community

Collectively enhanced Ramsey readout by cavity sub- to superradiant transition

When an inverted ensemble of atoms is tightly packed on the scale of its emission wavelength or when the atoms are collectively strongly coupled to a single cavity mode, their dipoles will align and decay rapidly via a superradiant burst. However, a spread-out dipole phase distribution theory predicts a required minimum threshold of atomic excitation for superradiance to occur. Here we experimentally confirm this predicted threshold for superradiant emission on a narrow optical transition when exciting the atoms transversely and show how to take advantage of the resulting sub- to superradiant transition. A $\pi/2$-pulse places the atoms in a subradiant state, protected from collective cavity decay, which we exploit during the free evolution period in a corresponding Ramsey pulse sequence. The final excited state population is read out via superradiant emission from the inverted atomic ensemble after a second $\pi/2$-pulse, and with minimal heating this allows for multiple Ramsey sequences within one experimental cycle. Our scheme is a fundamentally new approach to atomic state readout characterized by its speed, simplicity, and high sensitivity. It demonstrates the potential of sensors using collective effects in cavity-coupled quantum emitters

An organic borate salt with superior p‐doping capability for organic semiconductors

Molecular doping allows enhancement and precise control of electrical properties of organic semiconductors, and is thus of central technological relevance for organic (opto‐) electronics. Beyond single‐component molecular electron acceptors and donors, organic salts have recently emerged as a promising class of dopants. However, the pertinent fundamental understanding of doping mechanisms and doping capabilities is limited. Here, the unique capabilities of the salt consisting of a borinium cation (Mes2B+; Mes: mesitylene) and the tetrakis(penta‐fluorophenyl)borate anion [B(C6F5)4]− is demonstrated as p‐type dopant for polymer semiconductors. With a range of experimental methods, the doping mechanism is identified to comprise electron transfer from the polymer to Mes2B+, and the positive charge on the polymer is stabilized by [B(C6F5)4]−. Notably, the former salt cation leaves during processing and is not present in films. The anion [B(C6F5)4]− even enables the stabilization of polarons and bipolarons in poly(3‐hexylthiophene), not yet achieved with other molecular dopants. From doping studies with high ionization energy polymer semiconductors, the effective electron affinity of Mes2B+[B(C6F5)4]− is estimated to be an impressive 5.9 eV. This significantly extends the parameter space for doping of polymer semiconductors

Temporal Dynamics of Chronic Inflammation on the Cecal Microbiota in IL-10-/- Mice

The intestinal microbiota is a critical component of mucosal health as evidenced by the fact that alterations in the taxonomic composition of the gastrointestinal microbiota are associated with inflammatory bowel diseases. To better understand how the progression of inflammation impacts the composition of the gastrointestinal microbiota, we used culture independent taxonomic profiling to identify temporal changes in the cecal microbiota of C3Bir IL-10-/- mice concomitantly with the onset and progression of colitis. This analysis revealed that IL-10-/- mice displayed a biphasic progression in disease severity, as evidenced by histopathological scores and cytokine production. Beginning at 4 weeks of age, pro-inflammatory cytokines including TNF-a, IFN-g, IL-6, G- CSF, and IL-1a as well as chemokines including RANTES and MIP-1a were elevated in the serum of IL-10-/- mice. By 19 weeks of age, the mice developed clinical signs of disease as evidenced by weight loss, which was accompanied by a significant increase in serum levels of KC and IL-17. While the overall diversity of the microbiota of both wild type and IL-10-/- were similar in young mice, the latter failed to increase in complexity as the mice matured and experienced changes in abundance of specific bacterial taxa that are associated with inflammatory bowel disease in humans. Collectively, these results reveal that there is a critical time in young mice between four to six weeks of age when inflammation and the associated immune responses adversely affect maturation of the microbiota

An Organic Borate Salt with Superior p‐Doping Capability for Organic Semiconductors

Molecular doping allows enhancement and precise control of electrical properties of organic semiconductors, and is thus of central technological relevance for organic (opto‐) electronics. Beyond single‐component molecular electron acceptors and donors, organic salts have recently emerged as a promising class of dopants. However, the pertinent fundamental understanding of doping mechanisms and doping capabilities is limited. Here, the unique capabilities of the salt consisting of a borinium cation (Mes2B+; Mes: mesitylene) and the tetrakis(penta‐fluorophenyl)borate anion [B(C6F5)4]− is demonstrated as p‐type dopant for polymer semiconductors. With a range of experimental methods, the doping mechanism is identified to comprise electron transfer from the polymer to Mes2B+, and the positive charge on the polymer is stabilized by [B(C6F5)4]−. Notably, the former salt cation leaves during processing and is not present in films. The anion [B(C6F5)4]− even enables the stabilization of polarons and bipolarons in poly(3‐hexylthiophene), not yet achieved with other molecular dopants. From doping studies with high ionization energy polymer semiconductors, the effective electron affinity of Mes2B+[B(C6F5)4]− is estimated to be an impressive 5.9 eV. This significantly extends the parameter space for doping of polymer semiconductors.Peer Reviewe