Rapid Insertion Research Articles

Methane oxidation by the copper methane monooxygenase: Before and after the cryogenic electron microscopy structure of particulate methane monooxygenase from Methylococcus capsulatus (Bath)

AbstractThe particulate methane monooxygenase (pMMO) is a copper monooxygenase that converts methane into methanol in methanotrophic bacteria. As this enzyme converts methane into methanol efficiently and selectively under ambient conditions, it has become the paradigm for understanding the design of nature to facilitate this process so that we could develop a biomimetic catalyst to accomplish this difficult C1 chemistry in the laboratory. With the advent of the recent 2.5 Å cryo‐electron microscopy structure of the pMMO from Methylococcus capsulatus (Bath), it is now evident that the catalytic site of hydroxylation in pMMO is a CuICuICuI tricopper cluster (CuI: copper ions) sequestered within the transmembrane domain of this protein complex. With three reducing equivalents embodied in this structural motif, the tricopper cluster can react with O2 to irreversibly cleave the OO bond to harness the highly reactive oxene for rapid and direct insertion into the CH bonds of methane. Here, we review the structural, biochemical, and biophysical studies over the past three decades that have culminated in this important advance in the chemistry of methane oxidation.

Rapid shear stress-dependent ENaC membrane insertion is mediated by the endothelial glycocalyx and the mineralocorticoid receptor

The contribution of the shear stress-sensitive epithelial Na+ channel (ENaC) to the mechanical properties of the endothelial cell surface under (patho)physiological conditions is unclear. This issue was addressed in in vivo and in vitro models for endothelial dysfunction. Cultured human umbilical vein endothelial cells (HUVEC) were exposed to laminar (LSS) or non-laminar shear stress (NLSS). ENaC membrane insertion was quantified using Quantum-dot-based immunofluorescence staining and the mechanical properties of the cell surface were probed with the Atomic Force Microscope (AFM) in vitro and ex vivo in isolated aortae of C57BL/6 and ApoE/LDLR-/- mice. Flow- and acetylcholine-mediated vasodilation was measured in vivo using magnetic resonance imaging. Acute LSS led to a rapid mineralocorticoid receptor (MR)-dependent membrane insertion of ENaC and subsequent stiffening of the endothelial cortex caused by actin polymerization. Of note, NLSS stress further augmented the cortical stiffness of the cells. These effects strongly depend on the presence of the endothelial glycocalyx (eGC) and could be prevented by functional inhibition of ENaC and MR in vitro endothelial cells and ex vivo endothelial cells derived from C57BL/6, but not ApoE/LDLR-/- vessel. In vivo In C57BL/6 vessels, ENaC- and MR inhibition blunted flow- and acetylcholine-mediated vasodilation, while in the dysfunctional ApoE/LDLR-/- vessels, this effect was absent. In conclusion, under physiological conditions, endothelial ENaC, together with the glycocalyx, was identified as an important shear stress sensor and mediator of endothelium-dependent vasodilation. In contrast, in pathophysiological conditions, ENaC-mediated mechanotransduction and endothelium-dependent vasodilation were lost, contributing to sustained endothelial stiffening and dysfunction.

Efficient targeted transgenesis of large donor DNA into multiple mouse genetic backgrounds using bacteriophage Bxb1 integrase

The development of mouse models of human disease and synthetic biology research by targeted transgenesis of large DNA constructs represent a significant genetic engineering hurdle. We developed an efficient, precise, single-copy integration of large transgenes directly into zygotes using multiple mouse genetic backgrounds. We used in vivo Bxb1 mediated recombinase-mediated cassette exchange (RMCE) with a transgene “landing pad” composed of dual heterologous Bxb1 attachment (att) sites in cis, within the Gt(ROSA)26Sor safe harbor locus. RMCE of donor was achieved by microinjection of vector DNA carrying cognate attachment sites flanking the donor transgene with Bxb1-integrase mRNA. This approach achieves perfect vector-free integration of donor constructs at efficiencies > 40% with up to ~ 43 kb transgenes. Coupled with a nanopore-based Cas9-targeted sequencing (nCATS), complete verification of precise insertion sequence was achieved. As a proof-of-concept we describe the development of C57BL/6J and NSG Krt18-ACE2 models for SARS-CoV2 research with verified heterozygous N1 animals within ~ 4 months. Additionally, we created a series of mice with diverse backgrounds carrying a single att site including FVB/NJ, PWK/PhJ, NOD/ShiLtJ, CAST/EiJ and DBA/2J allowing for rapid transgene insertion. Combined, this system enables predictable, rapid development with simplified characterization of precisely targeted transgenic animals across multiple genetic backgrounds.

BISON validation of FeCrAl cladding mechanical failure during simulated reactivity-initiated accident conditions

A reactivity-initiated accident (RIA) is a postulated design basis accident in light water reactors (LWRs) in which a rapid reactivity insertion induces a fission rate increase and a fuel pellet temperature rise. During RIA, the fuel pellet thermally expands and may cause pellet-cladding mechanical interaction (PCMI). Separate effects PCMI tests were performed on C26M FeCrAl cladding tube samples, introducing biaxial stress via a well understood modified burst test (MBT) system. A high-speed camera in the MBT system captured the projections, covering a 360° view of the cladding deformation and enabling a digital image correlation (DIC) method to quantify the surface strains with high fidelity. Representative hot zero-power RIA mechanical loading conditions were applied to the sample, and the test duration ranged from 20 to 500 ms at an average temperature of 573 K. BISON finite element–based fuel performance code modeling was performed against the high-fidelity DIC data produced from the MBTs. Validation calculations were conducted with 2D models and systematically compared with test data of the burst time, burst pressure, burst hoop strains, and hoop strain rates. Based on the behaviors from the separate effects test, BISON calculations satisfactorily predicted the cladding deformation behaviors. Sensitivity analysis was conducted to identify highly influential mechanical properties responsible for the cladding failure behavior during the MBT experiments. The results highlight the significance of the cladding's mechanical strength in governing cladding strain, followed by the significance of the mechanical interactions between the pellet and the cladding.

Open technique for supra-acetabular pin placement in pelvic external fixation: a cadaveric study

BackgroundStandard supra-acetabular pin placement still needs fluoroscopic guidance, which is technically demanding for an untrained surgeon due to the unfamiliar fluoroscopic view and the risk of damaging some structures. The risks associated with the open technique without fluoroscopy have not yet been investigated, despite the palpable entry point and large bony corridor for rapid insertion in the limited time available for the management of unstable pelvic fracture patients. The aim of this study was to compare the open technique without fluoroscopy to the fluoroscopically assisted percutaneous technique for the positioning of supra-acetabular screws in cadavers without pelvic instability.Materials and methodsThe open technique for half-pin placement was compared to standard fluoroscopic guidance in 16 hemipelves (8 cadavers). The open technique was first performed on one side in each cadaver after simple randomization, followed by standard fluoroscopic guidance on the other side. In the open technique group, a Schanz pin 5 mm in diameter and 200 mm in length was inserted in the area just above the anteroinferior iliac spine (AIIS) and aimed with a medial inclination of 20° and a cephalad inclination of 10–20° after a 2 cm pilot drill hole had been established. Standard fluoroscopically guided pin placement was performed on the other side. Fluoroscopic assessment was conducted after final pin placement on both sides. The lateral femoral cutaneous nerve of the thigh (LFCN) and the hip capsule were identified via the Smith–Peterson approach. After complete dissection of soft tissue, it was clearly apparent that pin penetration was conducted outside the bony corridor.ResultsThe LFCN was found to be in a risk zone near the pin (mean distance, 15 mm; range, 0–30 mm). One LFCN may have been injured in the fluoroscopic guidance group. The mean medial inclination of the pin was 19.8° (range, 5–40°) and the mean cephalad inclination was 11.5° (range 0–20°) in the open technique group. The mean medial inclination of the pin was 30.4° (range, 20–45°) and the mean cephalad inclination was 19.3° (range, 2–35°) in the fluoroscopic guidance group. The mean distance of the pin entry point from the AIIS was 11.1 mm (range, 0–35 mm) in the open technique group. The mean distance of the entry point of the pin from the AIIS was 15.1 mm (range, 0–25 mm) in the fluoroscopic guidance group. The mean hip joint capsule distance was 12 mm (range, 8–25 mm). No joint penetration was observed in the open technique group, compared to one joint penetration in the fluoroscopic guidance group. No sciatic notch penetration was found in either group, but pin penetration outside the external cortex of the ilium was found only in the open technique group, in 4 hemipelves.ConclusionsThis study shows that the freehand technique performed by experienced trauma surgeons may be as acceptable as controlled pin insertion under image intensification for selecting the proper entry point and stabilizing the anterior pelvic ring.

The temperature dependence of soot formation in laminar coflow aromatic flames

The temperature sensitivity of n-propylbenzene and 1,2,4-trimethylbenzene on soot formation in coflow diffusion flames was assessed. Cases with air temperatures at 300K (LT), 473K (MT), and 673K (HT) were established. Soot volume fractions and primary particle diameters were measured by Laser-induced incandescence. Soot temperatures were measured by rapid thermocouple insertion with correction by backward extrapolation. Soot yield also increased with temperature. Compared to alkanes and alkenes, alkylbenzenes exhibited much lower temperature sensitivity. The model suggested that elevating the reactant temperature did not significantly affect the production of soot precursor PAH in alkylbenzene flames, but altered the buoyancy-induced acceleration, which subsequently determined the time available for soot growth. Soot formation was promoted by extending the available time. To isolate the impact of fuel temperature, a case with heated fuel and unheated air (FHT) was also assessed. It is found that raising the fuel temperature affected soot formation more along the centerline than on the wing. This is suggested to be related to the earlier soot inception for FHT along the centerline.

3D hetero-nanostructured electrode constructed on carbon fiber paper with 2D 1T-MoS2/1D Cu(OH)2 for flexible asymmetric solid-state supercapacitors

One-dimensional Cu(OH)2 nanorods and two-dimensional 1T-MoS2 nanosheets have attracted attention due to their attractive electrochemical properties. However, 1T-MoS2 nanosheets tend to agglomerate and transform to 2H-MoS2, resulting in a decrease in electrochemical performance. In this study, flexible electrodes with 3D hetero-nanostructures are constructed by growing Cu(OH)2 nanorod arrays and loading 1T-MoS2 nanosheets on carbon fiber paper made of chopped carbon fibers as a conductive flexible substrate. The flower-shaped 1T-MoS2 nanosheets with increased interlayer spacing are conducive to the rapid diffusion and insertion of electrolyte, while the conductive copper hydroxide nanorod array and carbon fiber paper can facilitate electron transport. The 1T-MoS2/Cu(OH)2@CFP based electrode has a high areal capacitance of 1124.0 mF cm−2 at 1 mA cm−2 and excellent cycle stability (with 98.3% capacitance retention after 10000 charge-discharge cycles). Furthermore, a flexible asymmetric solid-state supercapacitor (FASSC) device based on the as-prepared 1T-MoS2/Cu(OH)2@CFP electrode exhibits an energy density of 0.130 mWh cm−2 at a power density of 0.375 mW cm−2. The capacitance of FASSC device remains 90.8% of the initial value after 20000 cycles. In addition, the CFP substrate can be bent at a large angle and folded into different shapes, which makes 1T-MoS2/Cu(OH)2@CFP based electrodes suitable for flexible and portable electronics.

Borane Adducts of Aromatic Phosphorus Heterocycles: Synthesis, Crystallographic Characterization and Reactivity of a Phosphinine-B(C6 F5 )3 Lewis Pair.

A phosphinine‐borane adduct of a Me3Si‐functionalized phosphinine and the Lewis acid B(C6F5)3 has been synthesized and characterized crystallographically for the first time. The reaction strongly depends on the nature of the substituents in the α‐position of the phosphorus heterocycle. In contrast, the reaction of B2H6 with various substituted phosphinines leads to an equilibrium between the starting materials and the phosphinine–borane adducts that is determined by the Lewis basicity of the phosphinine. The novel phosphinine borane adduct (6‐B(C6F5)3) shows rapid and facile insertion and [4+2] cycloaddition reactivity towards phenylacetylene. A hitherto unknown dihydro‐1‐phosphabarrelene is formed with styrene. The reaction with an ester provides a new, facile and selective route to 1‐R‐phosphininium salts. These salts then undergo a [4+2] cycloaddition in the presence of Me3Si−C≡CH and styrene to cleanly form unprecedented derivatives of 1‐R‐phosphabarrelenium salts.

Superior Conjugative Plasmids Delivered by Bacteria to Diverse Fungi.

Fungi are nature's recyclers, allowing for ecological nutrient cycling and, in turn, the continuation of life on Earth. Some fungi inhabit the human microbiome where they can provide health benefits, while others are opportunistic pathogens that can cause disease. Yeasts, members of the fungal kingdom, have been domesticated by humans for the production of beer, bread, and, recently, medicine and chemicals. Still, the great untapped potential exists within the diverse fungal kingdom. However, many yeasts are intractable, preventing their use in biotechnology or in the development of novel treatments for pathogenic fungi. Therefore, as a first step for the domestication of new fungi, an efficient DNA delivery method needs to be developed. Here, we report the creation of superior conjugative plasmids and demonstrate their transfer via conjugation from bacteria to 7 diverse yeast species including the emerging pathogen Candida auris. To create our superior plasmids, derivatives of the 57 kb conjugative plasmid pTA-Mob 2.0 were built using designed gene deletions and insertions, as well as some unintentional mutations. Specifically, a cluster mutation in the promoter of the conjugative gene traJ had the most significant effect on improving conjugation to yeasts. In addition, we created Golden Gate assembly-compatible plasmid derivatives that allow for the generation of custom plasmids to enable the rapid insertion of designer genetic cassettes. Finally, we demonstrated that designer conjugative plasmids harboring engineered restriction endonucleases can be used as a novel antifungal agent, with important applications for the development of next-generation antifungal therapeutics.

Real-Time Control of Active Catheter Signals for Better Visual Profiling During Cardiovascular Interventions Under MRI Guidance

In MR-guided interventional procedures, RF coils can be attached to the instruments to provide a positive MR signal for device tracking. The signal from these coils can vary strongly over the procedure and mask the surrounding anatomy. The purpose of this study is to introduce and demonstrate a low-cost, vendor- and device-independent interface circuit that allows the interventionalist to adjust the active device signal intensity. In this work a variable attenuator circuit was constructed to control the tip signal of an active coronary artery catheter in real-time from within the MR scanner room. Performance of the attenuator circuit and the active catheter was characterized on the test bench, in a phantom model, and in vivo. The system was used in a pig model at 3T during the introduction of the catheter into the left coronary artery. The circuit could attenuate the amplitude of the tracking coil signal by up to 20 dB. Without attenuation, the tracking coil signal intensity was masking anatomical details of the coronary ostium making it impossible to reliably introduce the catheter into the artery. After interactive adjustment, which was performed in a few seconds by the interventionalist, the improved visualization of the vascular anatomy enabled a rapid insertion of the catheter into the coronary ostium. The vendor-independent variable attenuator provides real-time control of the catheter signal without interrupting the image acquisition. Even though most MRI systems can control the individual signal levels from coils by software, the attenuator hardware is advantageous as it can be integrated into any MR-system, and it provides a direct interface for the interventionalist at the magnet.

Livermore tomography tools: Accurate, fast, and flexible software for tomographic science

This paper introduces the capabilities and availability of a customizable scientific software package called Livermore Tomography Tools (LTT) built for computed tomography (CT) research. It was initially developed to process x-ray and neutron CT data accurately and rapidly from raw detector counts to reconstructed volumes with the flexibility to handle many special cases. Our goals were to provide quantitatively accurate results reported in physical units (e.g., mm−1 or cm−1) while exploiting all available computational advantages to maximize speed and conserve memory. Written in C/C++ with support for multiple CPUs and GPUs, LTT runs on many computing platforms (Linux/Unix, Windows, and Mac; laptops to supercomputers). As a result, LTT can: process data acquired from various custom-built and commercially available CT scanners, model and simulate x-ray and neutron interactions to encourage algorithm prototyping, and allow for rapid insertion of the latest algorithms. We describe LTT's software architecture, user interfaces, and its 88 algorithms (as of this writing) for pre-processing, reconstruction, post-processing, and simulation that support many scanner geometries (parallel-, fan-, cone-beam, and custom). Several applications are presented that illustrate LTT's accuracy, speed, and flexibility relative to other solutions.

An analysis of international use of robots for COVID-19

This article analyses data collected from press reports, social media, and the scientific literature on 338 instances of robots used explicitly in response to COVID-19 from 24 Jan, 2020, to 23 Jan, 2021, in 48 countries. The analysis was guided by four overarching questions: (1) What were robots used for in the COVID-19 response? (2) When were they used? (3) How did different countries innovate? and 4) Did having a national policy on robotics influence a country’s innovation and insertion of robotics for COVID-19? The findings indicate that robots were used for six different sociotechnical work domains and 29 discrete use cases. When robots were used varied greatly on the country; although many countries did report an increase at the beginning of their first surge. To understand the findings of how innovation occurred, the data was examined through the lens of the technology’s maturity according to NASA’s Technical Readiness Assessment metrics. Through this lens, findings note that existing robots were used for more than 78% of the instances; slightly modified robots made up 10%; and truly novel robots or novel use cases constituted 12% of the instances. The findings clearly indicate that countries with a national robotics initiative were more likely to use robotics more often and for broader purposes. Finally, the dataset and analysis produces a broad set of implications that warrant further study and investigation. The results from this analysis are expected to be of value to the robotics and robotics policy community in preparing robots for rapid insertion into future disasters.

Insertion of Calcium-Permeable AMPA Receptors during Epileptiform Activity In Vitro Modulates Excitability of Principal Neurons in the Rat Entorhinal Cortex.

Epileptic activity leads to rapid insertion of calcium-permeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (CP-AMPARs) into the synapses of cortical and hippocampal glutamatergic neurons, which generally do not express them. The physiological significance of this process is not yet fully understood; however, it is usually assumed to be a pathological process that augments epileptic activity. Using whole-cell patch-clamp recordings in rat entorhinal cortex slices, we demonstrate that the timing of epileptiform discharges, induced by 4-aminopyridine and gabazine, is determined by the shunting effect of Ca2+-dependent slow conductance, mediated predominantly by K+-channels. The blockade of CP-AMPARs by IEM-1460 eliminates this extra conductance and consequently increases the rate of discharge generation. The blockade of NMDARs reduced the additional conductance to a lesser extent than the blockade of CP-AMPARs, indicating that CP-AMPARs are a more significant source of intracellular Ca2+. The study’s main findings were implemented in a mathematical model, which reproduces the shunting effect of activity-dependent conductance on the generation of discharges. The obtained results suggest that the expression of CP-AMPARs in principal neurons reduces the discharge generation rate and may be considered as a protective mechanism.

A versatile genetic toolbox for Prevotella copri enables studying polysaccharide utilization systems

Prevotella copri is a prevalent inhabitant of the human gut and has been associated with plant‐rich diet consumption and diverse health states. The underlying genetic basis of these associations remains enigmatic due to the lack of genetic tools. Here, we developed a novel versatile genetic toolbox for rapid and efficient genetic insertion and allelic exchange applicable to P. copri strains from multiple clades. Enabled by the genetic platform, we systematically investigated the specificity of polysaccharide utilization loci (PULs) and identified four highly conserved PULs for utilizing arabinan, pectic galactan, arabinoxylan, and inulin, respectively. Further genetic and functional analysis of arabinan utilization systems illustrate that P. copri has evolved two distinct types of arabinan‐processing PULs (PULAra) and that the type‐II PULAra is significantly enriched in individuals consuming a vegan diet compared to other diets. In summary, this genetic toolbox will enable functional genetic studies for P. copri in future.

868 The management of acute lower gastrointestinal bleeding using a Sengstaken-Blakemore tube

Abstract Introduction Acute lower gastrointestinal haemorrhage can potentially be life-threatening. We present a case of a massive rectal bleed which was managed successfully with a balloon tamponade device designed for upper gastrointestinal haemorrhage. Presentation of case A 75-year-old gentleman, with a history of human immunodeficiency virus and cirrhosis with portal hypertension, presented with bright red rectal bleeding. Investigations showed a low haemoglobin level (74 g/L) and deranged clotting. Oesophago-gastro-duodenoscopy demonstrated no fresh or altered blood. Flexible sigmoidoscopy revealed active bleeding from a varix within the anterior rectal wall 4 cm from the anal verge. Efforts to stop the bleeding, including endoscopic clips, adrenaline injection and rectal packing, were unsuccessful and the patient became haemodynamically unstable. A Sengstaken-Blakemore tube was inserted per rectum and the gastric balloon was inflated to tamponade the lower rectum. The oesophageal balloon was then inflated to hold the gastric balloon firmly in place. A computed tomography angiogram demonstrated no evidence of haemorrhage with balloon tamponade. After 36 h, the balloon was removed with no further episodes of bleeding. Discussion The application of a balloon tamponade device should be considered in the management algorithm for acute lower gastrointestinal bleed. Advantages include its rapid insertion, immediate results and ability to measure further bleeding after the catheter has been placed. Conclusions Sengstaken-Blakemore tube per rectum may effectively control massive low rectal bleeding when alternative methods have been unsuccessful.

An easy-to-use CRISPRi plasmid tool for inducible knockdown in E. coli

CRISPR-interference (CRISPRi) is a powerful genetic tool with wide application in bacteria. In this work a single plasmid system is presented which expresses deactivated Cas9 and a short guide RNA sequence from separate inducible promoters, enabling up to 40-fold repression of target genes with minimal leaky repression in the uninduced state. The plasmid is designed for rapid spacer insertion with easy screening for correct clones, and a simple one-day protocol with >99.9% assembly efficiency is described. This plasmid is made available to the research community with a view to facilitating wider use of CRISPRi in bacterial systems.

Optimized two-step electroporation process to achieve efficient nonviral-mediated gene insertion into primary T cells.

The development of gene editing technologies over the past years has allowed the precise and efficient insertion of transgenes into the genome of various cell types. Knock‐in approaches using homology‐directed repair and designer nucleases often rely on viral vectors, which can considerably impact the manufacturing cost and timeline of gene‐edited therapeutic products. An attractive alternative would be to use naked DNA as a repair template. However, such a strategy faces challenges such as cytotoxicity from double‐stranded DNA (dsDNA) to primary cells. Here, we sought to study the kinetics of transcription activator‐like effector nuclease (TALEN)‐mediated gene editing in primary T cells to improve nonviral gene knock‐in. Harnessing this knowledge, we developed a rapid and efficient gene insertion strategy based on either short single‐stranded oligonucleotides or large (2 Kb) linear naked dsDNA sequences. We demonstrated that a time‐controlled two‐step transfection protocol can substantially improve the efficiency of nonviral transgene integration in primary T cells. Using this approach, we achieved modification of up to ˜ 30% of T cells when inserting a chimeric antigen receptor (CAR) at the T‐cell receptor alpha constant region (TRAC) locus to generate ‘off‐the shelf’ CAR‐T cells.

TEAseq-based identification of 35,696 Dissociation insertional mutations facilitates functional genomic studies in maize

In plants, transposable element (TE)-triggered mutants are important resources for functional genomic studies. However, conventional approaches for genome-wide identification of TE insertion sites are costly and laborious. This study developed a novel, rapid, and high-throughput TE insertion site identification workflow based on next-generation sequencing and named it Transposable Element Amplicon Sequencing (TEAseq). Using TEAseq, we systemically profiled the Dissociation (Ds) insertion sites in 1606 independent Ds insertional mutants in advanced backcross generation using K17 as background. The Ac-containing individuals were excluded for getting rid of the potential somatic insertions. We characterized 35,696 germinal Ds insertions tagging 10,323 genes, representing approximately 23.3% of the total genes in the maize genome. The insertion sites were presented in chromosomal hotspots around the ancestral Ds loci, and insertions occurred preferentially in gene body regions. Furthermore, we mapped a loss-of-function AGL2 gene using bulked segregant RNA-sequencing assay and proved that AGL2 is essential for seed development. We additionally established an open-access database named MEILAM for easy access to Ds insertional mutations. Overall, our results have provided an efficient workflow for TE insertion identification and rich sequence-indexed mutant resources for maize functional genomic studies.

Safety of a New Sinus Irrigation Device in Rhinosinusitis: A Pilot Study.

Puncture and lavage of the paranasal sinuses, previously the primary treatment for unresponsive acute bacterial rhinosinusitis before surgery, has been abandoned due to procedural discomfort and advancements in antibiotic efficacy and endoscopic surgery. The rise in antibiotic-resistant bacteria has renewed the interest in minimally invasive sinus lavage to both avoid aggressive surgical interventions and identify appropriate antibiotic therapy. In this article, we describe the safety and feasibility of a new device in human patients and evaluate its efficacy as a treatment before the traditional sinus surgery in acute rhinosinusitis. The device with its seeker-shaped guiding tube and rotating wire can enter the sinus cavity through the natural ostium, pulverize the inspissated mucus, and enable lavage and culture sampling without the need for sinus puncturing. It was tested in 6 patients with chronic sinusitis under general anesthesia during endoscopic sinus surgery and in additional 10 patients with maxillary acute bacterial rhinosinusitis in outpatient settings under local anesthesia. The device enabled rapid, efficient, and atraumatic insertion of the wire into the occluded sinuses. The rotating wire permitted pulverization of the thick mucus, which enabled irrigation without mucosal damage or adverse events. Overall, 9 of 10 patients with acute bacterial rhinosinusitis demonstrated remarkable improvements and were discharged the following day with no acute symptoms. The visual analog scale score for pain dropped from 8.9 to 0.4. The remaining one patient underwent endoscopic sinus surgery subsequently. None of the patients treated during endoscopic sinus surgery developed any adverse events.

Effects of ammonia addition on soot formation in ethylene laminar diffusion flames

In light of the increasingly stringent pollutant emission regulation and energy crisis, ammonia (NH3) has been regarded as a highly competitive alternative fuel. Previous studies mainly focused on the fundamental combustion characteristics and NOx emission of co-firing NH3 with hydrocarbons; however, soot emission was rarely studied. In this study, effects of NH3 addition with varying ratios (between 0% and 60% by mole fraction while the remainder is argon) on soot formation in ethylene (40% by mole fraction) laminar diffusion flames were experimentally and numerically investigated. Two-color laser induced incandescence and planar laser induced fluorescence method were used to measure the spatial distributions of soot volume fraction, polycyclic aromatic hydrocarbons (PAHs), and OH radical. Temperature profiles along the flame centerline were obtained through rapid thermocouple insertion technique. Results show that with NH3 addition, the flame height increases and the temperature at the same height decreases. Peak concentration and total loading show that the inhibitory effect of NH3 addition on PAHs and soot volume fraction (SVF) is in the order: A1 < A2&A3 < A4 < SVF. The primary particle size obtained by transmission electron microscope substantially decreases with the increasing NH3. In addition, the signal intensity of OH radical was diminished, indicating that instead of promoting the soot oxidation, NH3 reduces soot formation by inhibiting PAH growth, soot inception, and surface growth. Chemical kinetic analysis suggests that NH3 addition reduces the concentrations of H, C2H2, and C3H3, thus markedly inhibiting the rate-limiting step of A1 formation and PAH growth.