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Identification of the key biotic and abiotic drivers within food webs is important for understanding species abundance changes in ecosystems, particularly across ecotones where there may be strong variation in interaction strengths. Using structural equation models (SEMs) and four decades of integrated data from the San Francisco Estuary, we investigated the relative effects of top‐down, bottom‐up, and environmental drivers on multiple trophic levels of the pelagic food web along an estuarine salinity gradient and at both annual and monthly temporal resolutions. We found that interactions varied across the estuarine gradient and that the detectability of different interactions depended on timescale. For example, for zooplankton and estuarine fishes, bottom‐up effects appeared to be stronger in the freshwater upstream regions, while top‐down effects were stronger in the brackish downstream regions. Some relationships (e.g., bottom‐up effects of phytoplankton on zooplankton) were seen primarily at annual timescales, whereas others (e.g., temperature effects) were only observed at monthly timescales. We also found that the net effect of environmental drivers was similar to or greater than bottom‐up and top‐down effects for all food web components. These findings can help identify which trophic levels or environmental factors could be targeted by management actions to have the greatest impact on estuarine forage fishes and the spatial and temporal scale at which responses might be observed. More broadly, this study highlights how environmental gradients can structure community interactions and how long‐term data sets can be leveraged to generate insights across multiple scales. [ABSTRACT FROM AUTHOR]

Restoration of coastal wetlands has the potential to deliver both climate change mitigation, called blue carbon, and adaptation benefits to coastal communities, as well as supporting biodiversity and providing additional ecosystem services. Valuing carbon sequestration may incentivize restoration projects; however, it requires development of rigorous methods for quantifying blue carbon sequestered during coastal wetland restoration. We describe the development of a blue carbon accounting model (BlueCAM) used within the Tidal Restoration of Blue Carbon Ecosystems Methodology Determination 2022 of the Emissions Reduction Fund (ERF), which is Australia's voluntary carbon market scheme. The new BlueCAM uses Australian data to estimate abatement from carbon and greenhouse gas sources and sinks arising from coastal wetland restoration (via tidal restoration) and aligns with the Intergovernmental Panel for Climate Change guidelines for national greenhouse gas inventories. BlueCAM includes carbon sequestered in soils and biomass and avoided emissions from alternative land uses. A conservative modeled approach was used to provide estimates of abatement (as opposed to on‐ground measurements); and in doing so, this will reduce the costs associated with monitoring and verification for ERF projects and may increase participation in blue carbon projects by Australian landholders. BlueCAM encompasses multiple climate regions and plant communities and therefore may be useful to others outside Australia seeking to value blue carbon benefits from coastal wetland restoration. [ABSTRACT FROM AUTHOR]

Objective: Somatosensory feedback from upper airway structures is essential for swallowing and airway defense but little is known about the identities and distributions of human upper airway neurons. Furthermore, whether sensory innervation modifies with aging is unknown. In this study, we quantify neuronal and chemosensory cell density in upper airway structures and correlate with age. Methods: Participants underwent biopsies from base of tongue, lateral and midline pharyngeal wall, epiglottis, and arytenoids (N = 25 13 female/12 male; 20–80 years, mean 51.4 years without clinical diagnosis of dysphagia or clinical indication for biopsy). Tissue sections were labeled with antibodies for all neurons, myelinated neurons, and chemosensory cells. Densities of lamina propria innervation, epithelial innervation, solitary chemosensory cells, and taste buds were calculated and correlated with age. Results: Arytenoid had the highest density of innervation and chemosensory cells across all measures compared to other sites. Taste buds were frequently observed in arytenoid and epiglottis. Base of tongue, lateral pharynx, and midline posterior pharynx had minimal innervation and few chemosensory cells. Epithelial innervation was present primarily in close proximity to chemosensory cells and taste buds. Overall innervation and myelinated fibers in the arytenoid lamina propria decline with aging. Conclusion: Findings establish the architecture of healthy adult sensory innervation and demonstrate the varied distribution of laryngopharyngeal innervation, necessary steps toward understanding the sensory basis for swallowing and airway defense. We also document age‐related decline in arytenoid innervation density. These findings suggest that sensory afferent denervation of the upper airway may be a contributing factor to presbyphagia. Level of Evidence: NA Laryngoscope, 133:773–784, 2023 [ABSTRACT FROM AUTHOR]

Background: Disorders of airway protection (cough and swallowing) are pervasive in Parkinson's disease (PD) resulting in a high incidence of aspiration pneumonia and death. However, there are no randomized controlled trials comparing strength and skill‐based approaches to improve airway protection in PD. Objectives: The aim of this study was to compare expiratory muscle strength training (EMST) and sensorimotor training for airway protection (smTAP) to improve cough‐related outcomes in people with PD. Methods: Participants with PD and dysphagia were recruited for this prospective phase II randomized‐blinded controlled clinical trial. Participants completed baseline assessment, 5 weeks of EMST or smTAP, and a post‐training assessment. Primary outcome measures included maximum expiratory pressure (MEP) and voluntary cough peak expiratory flow rate (PEFR). Mixed effects models were used to assess the effects of EMST and smTAP on outcomes. Results: A total of 65 participants received either EMST (n = 34) or smTAP (n = 31). MEP improved from pre‐ to post‐treatment for smTAP (P < 0.001, d = 0.19) and EMST (P < 0.001, d = 0.53). Voluntary PEFR increased from pre‐ to post‐treatment for smTAP (P < 0.001, d = 0.19) and EMST (P < 0.001, d = 0.06). Moreover, reflex cough PEFR (P < 0.001, d = 0.64), reflex cough expired volume (P < 0.001, d = 0.74), and urge to cough (P = 0.018, OR = 2.70) improved for the smTAP group but not for the EMST group. Conclusions: This clinical trial confirmed the efficacy of smTAP to improve reflex and voluntary cough function, above and beyond EMST, the current gold standard. © 2022 International Parkinson and Movement Disorder Society. [ABSTRACT FROM AUTHOR]

Melt extrusion pretreatment of poly(ethylene terephthalate) (PET) prior to enzymatic depolymerization with an unpurified leaf branch compost cutinase enzyme cocktail is explored to ascertain the efficiency gained by different processing methods on the enzymatic depolymerization of PET. Specific surface area (SSA) is investigated as a key factor in reducing depolymerization time. Higher SSA substrates (>5.6 mm2 mg−1) show higher depolymerization rates (≈0.88 g L−1 terephthalic acid [TPA] per day) and no induction phase, while lower SSA substrates (≈4.3, 4.4, and 5.6 mm2 mg−1) show, after an initial induction phase, similar depolymerization rates (≈0.46, 0.45, and 0.44 g L−1 TPA per day) despite increases in SSA of up to 30%. The mechanism of enzymatic depolymerization manifests in the appearance of anisotropic pitting. Longer incubation time used to overcome the induction phase in low SSA substrates allows for nearly full recovery of monomeric products, but manual pregrinding of extruded PET sharply increases SSA, depolymerization rate, and substrate crystallinity which may decrease the maximum recycled yield of the product materials. An estimate of the energy cost of increasing SSA is made and its effects on material properties are discussed. This work highlights key material structure and pretreatment aspects influencing the enzymatic recycling of PET. [ABSTRACT FROM AUTHOR]

The ability to assemble artificial systems that mimic aspects of natural light‐harvesting functions is fascinating and attractive for materials design. Given the complexity of such a system, a simple design pathway is desirable. Here, we argue that associative phase separation of oppositely charged conjugated polyelectrolytes (CPEs) can provide such a path in an environmentally benign medium: water. We find that complexation between an exciton–donor and acceptor CPE leads to formation of a complex fluid. We interrogate exciton transfer from the donor to the acceptor CPE within the complex fluid and find that transfer is highly efficient. We also find that excess molecular ions can tune the modulus of the inter‐CPE complex fluid. Even at high ion concentrations, CPEs remain complexed with significantly delocalized electronic wavefunctions. Our work lays the rational foundation for complex, tunable aqueous light‐harvesting systems via the intrinsic thermodynamics of associative phase separation. [ABSTRACT FROM AUTHOR]

A novel capillary‐based microfluidic strategy to accelerate the process of small‐molecule‐compound screening by room‐temperature X‐ray crystallography using protein crystals is reported. The ultra‐thin microfluidic devices are composed of a UV‐curable polymer, patterned by cleanroom photolithography, and have nine capillary channels per chip. The chip was designed for ease of sample manipulation, sample stability and minimal X‐ray background. 3D‐printed frames and cassettes conforming to SBS standards are used to house the capillary chips, providing additional mechanical stability and compatibility with automated liquid‐ and sample‐handling robotics. These devices enable an innovative in situ crystal‐soaking screening workflow, akin to high‐throughput compound screening, such that quantitative electron density maps sufficient to determine weak binding events are efficiently obtained. This work paves the way for adopting a room‐temperature microfluidics‐based sample delivery method at synchrotron sources to facilitate high‐throughput protein‐crystallography‐based screening of compounds at high concentration with the aim of discovering novel binding events in an automated manner. [ABSTRACT FROM AUTHOR]

The transmembrane protein, c‐Met, is thought to be overexpressed and activated in colorectal cancer (CRC). This study explored its potential as a diagnostic tissue biomarker for CRC in a large human CRC tissue collection obtained from a randomized clinical trial. Tissue microarrays of matched normal colorectal epithelium and primary cancer were prepared from specimens obtained from 280 patients recruited to the MRC CLASICC trial (ISRCTN 74883561) and interrogated using immunohistochemistry for c‐Met expression. The distribution and intensity of immunopositivity was graded using a validated, semi‐quantifiable score, and differences in median scores analysed using the Wilcoxon signed‐rank test. A receiver operating characteristic (ROC) curve was plotted to measure the diagnostic accuracy of c‐Met as a biomarker in CRC. Epithelial cell membrane expression of c‐Met differed significantly between CRC and normal colorectal tissue: median 12.00 (Interquartile range (IQR) 6‐15) versus median 6.00 (IQR 2.70‐12.00) respectively (P = <.0001). ROC‐AUC analysis of c‐Met expression yielded a CRC diagnostic probability of 0.66 (95% CI: 0.61 to 0.70; P <.0001). A score of ≥14.50 showed high specificity at 85.32% (95% CI 80.33%‐89.45%) but sensitivity of only 30.92% (CI 25.37%‐36.90%). Thus c‐Met is consistently overexpressed in human CRC as compared to normal colorectal epithelium tissue. c‐Met expression may have a role in diagnosis and prognostication if combined with other biomarkers. [ABSTRACT FROM AUTHOR]

Objective: To establish how oral bacteria are related to cough sensitivity and pneumonia in a clinical stroke population. Background: Stroke patients are at risk of colonisation by respiratory pathogens due, in part, to sudden discontinuation of effective oral hygiene. When combined with reduced cough reflex sensitivity, aspiration of contaminated oropharyngeal contents and can lead to pneumonia. Relationships between oral bacteria, cough sensitivity and pneumonia have not been established. Materials and methods: A total of 102 patients with acute stroke underwent saliva sampling and cough reflex testing at admission to hospital, discharge and one month. A qPCR assay compared levels of bacteria in saliva. Pneumonia events were recorded. Results: Relative levels of bacteria were lowest at admission to hospital (6.04 × 10−6). There was a slight (non‐significant) increase in bacterial levels at discharge (1.69 × 10−2, P =.73). By one month, bacterial levels had significantly increased (9.17 × 10−2) relative to admission [P <.001] and discharge [P <.001]. Pseudomonas aeruginosa, Klebsiella pneumoniae and Escherichia coli are not typically found in healthy mouths, yet were detected in 22% of patients during hospitalisation. Combined bacterial levels measured at one month was associated with pneumonia (P =.004) but there was no relationship to cough sensitivity. Conclusion: Acute stroke patients were at increased risk of colonisation from respiratory pathogens throughout their recovery. The presence of these pathogens in saliva at one month was associated with adverse respiratory events. Data support the development of protocols to explore risk factors and sequelae of microbiological changes in stroke. [ABSTRACT FROM AUTHOR]

Objectives: When swallowing function is compromised in patients with Parkinson's disease (PD), cough plays a crucial role in clearing the airway and preventing pulmonary complications. The aim of this study was to determine the influence of vocal fold atrophy severity as measured by the bowing index (BI) on airway protection in PD.Methods: Thirty participants with PD completed measures of voluntary and reflex cough. Flexible laryngoscopy with endoscopic evaluation of swallowing allowed for measurement of BI using ImageJ software. Swallowing safety was scored on the Penetration-Aspiration Scale (PAS). Regression and receiver operating characteristic (ROC) analyses were performed to test our study aim.Results: Twenty-four of 30 participants had some degree of vocal fold atrophy (BI >0). When controlling for age, disease duration did not significantly influence BI. BI was not predictive of any sensorimotor parameters of cough including measures of cough airflow, reflex cough threshold, or urge to cough. BI discriminated participants with near-normal (PAS 1-3) swallowing safety from participants with impaired (PAS 4-8) swallowing safety (P = .01, sensitivity: 87.0%, specificity: 71.4%, cutoff value BI >4.6).Conclusion: Vocal fold atrophy is a potential factor contributing to poor swallowing safety in PD. BI was not associated with cough function in this PD cohort, contrary to prior studies that have shown improved cough measures after vocal fold augmentation. Vocal fold atrophy in PD remains an important area of study as a targetable intervention for patients with airway protective dysfunction. Future studies should include measures of glottic closure during vocal fold adduction.Level Of Evidence: Level 3 Laryngoscope, 130:303-308, 2020. [ABSTRACT FROM AUTHOR]

Background: The evidence base regarding effective interventions for children and young people who experience abusive relationships, particularly domestic violence, is extremely limited. Aims: To evaluate the effectiveness of individual therapy for children and young people who have experienced abusive relationships; to address the challenges in carrying out such research. Methodology: A nonexperimental service evaluation repeated measures design with the administration of Routine Outcome Measures (ROMs) that assessed, skills, functioning and symptoms and experience of service. In total, 735 participants aged between 4 and 17 years were referred to the service. More than three quarters of those referred, attended at least three sessions and completed therapy. Results: The majority of those referred to the service presented with high needs. Mean scores on each of the ROMs improved and these changes were statistically significant. Based on clinical threshold scores, there was a deterioration for a small proportion of the sample (10% or less), improvements for between 28.5 and 49.4% and no change for the remainder. Statistical effect sizes, as measured by the ROMs, were generally in the medium range; satisfaction with the service was high. Implications: Gathering evidence to demonstrate the effectiveness, or not, of therapy is fraught with difficulties. In the research world, evaluation studies of "real world" interventions may be regarded as inferior to gold standard randomised controlled trials. However, such studies may be better at capturing everyday practice and what can be realistically achieved in terms of measuring effectiveness. There are important implications for commissioning and evaluating such interventions. [ABSTRACT FROM AUTHOR]

Potential changes to the El Niño-Southern Oscillation (ENSO) resulting from climate change may have far reaching impacts through atmospheric teleconnections. Here ENSO temperature and precipitation teleconnections between the historical and high-emission future simulations are compared in 40 models from phase 5 of the Coupled Model Intercomparison Project. Focusing on the global land area only, we show that there are robust increases in the spatial extent of ENSO teleconnections during austral summer in 2040-2089 of ~19% for temperature and ~12% for precipitation in the multimodel mean (MMM), relative to the 1950-1999 period. The MMM further shows that the expansion of ENSO teleconnection extent is at least partly related to a strengthening of ENSO teleconnections over continental regions; however, a consistent strengthening is not found across the individual models. This suggests that while more land may be affected by ENSO, the existing teleconnections may not be simply strengthened. [ABSTRACT FROM AUTHOR]

There has been increasing interest in complex coacervates for deriving and transporting biomaterials. Complex coacervates are a dense, polyelectrolyte-rich liquid that results from the electrostatic complexation of oppositely charged macroions. Coacervates have long been used as a strategy for encapsulation, particularly in food and personal care products. More recent efforts have focused on the utility of this class of materials for the encapsulation of small molecules, proteins, RNA, DNA, and other biomaterials for applications ranging from sensing to biomedicine. Furthermore, coacervate-related materials have found utility in other areas of biomedicine, including cartilage mimics, tissue culture scaffolds, and adhesives for wet, biological environments. Here, we discuss the self-assembly of complex coacervate-based materials, current challenges in the intelligent design of these materials, and their utility applications in the broad field of biomedicine. WIREs Nanomed Nanobiotechnol 2017, 9:e1442. doi: 10.1002/wnan.1442 For further resources related to this article, please visit the . [ABSTRACT FROM AUTHOR]

Background: Routine outcome monitoring has become a major focus of children and young people's mental health and counselling services in the United Kingdom, in the spirit of increasing user participation and delivering evidence ‐ based practice. In this pilot project, a group of young people were supported as co ‐ researchers to explore the ways in which counselling and therapy services measure their effectiveness. Aims: To explore young people's views of appropriate outcome measures of the effectiveness of therapy and to develop a novel user ‐ generated questionnaire. Methodology: The project was informed by co ‐ operative enquiry and participation research, whereby the co ‐ researchers were also co ‐ participants. Eight young people designed and created a novel questionnaire to assess the effectiveness of therapy and service satisfaction. The questionnaire focused explicitly on the actual benefits of therapy to young people, as perceived by themselves and expressed in their own words. This questionnaire was subsequently piloted with 66 participants attending a specialist counselling service for children and young people who have experienced abuse. Results: A reasonable spread of ratings to the individual items and few ‘Don't know’ responses suggested that the items were easy to understand and the rating scale functional. Total scores were positively skewed. Implications: Although there are challenges for co ‐ operative enquiry and meaningful participation research with young people, the limitations of current outcome evaluation require the development of more relevant and sensitive measures of children and young people's experiences of therapy. [ABSTRACT FROM AUTHOR]

Reported is the ability of α-helical polypeptides to self-assemble with oppositely-charged polypeptides to form liquid complexes while maintaining their α-helical secondary structure. Coupling the α-helical polypeptide to a neutral, hydrophilic polymer and subsequent complexation enables the formation of nanoscale coacervate-core micelles. While previous reports on polypeptide complexation demonstrated a critical dependence of the nature of the complex (liquid versus solid) on chirality, the α-helical structure of the positively charged polypeptide prevents the formation of β-sheets, which would otherwise drive the assembly into a solid state, thereby, enabling coacervate formation between two chiral components. The higher charge density of the assembly, a result of the folding of the α-helical polypeptide, provides enhanced resistance to salts known to inhibit polypeptide complexation. The unique combination of properties of these materials can enhance the known potential of fluid polypeptide complexes for delivery of biologically relevant molecules. [ABSTRACT FROM AUTHOR]

Serial methods for crystallography have the potential to enable dynamic structural studies of protein targets that have been resistant to single-crystal strategies. The use of serial data-collection strategies can circumvent challenges associated with radiation damage and repeated reaction initiation. This work utilizes a microfluidic crystallization platform for the serial time-resolved Laue diffraction analysis of macroscopic crystals of photoactive yellow protein (PYP). Reaction initiation was achieved via pulsed laser illumination, and the resultant electron-density difference maps clearly depict the expected pR1/pRE46Q and pR2/pRCW states at 10 µs and the pB1 intermediate at 1 ms. The strategies presented here have tremendous potential for extension to chemical triggering methods for reaction initiation and for extension to dynamic, multivariable analyses. [ABSTRACT FROM AUTHOR]

Renewed interest in room-temperature diffraction has been prompted by the desire to observe structural dynamics of proteins as they function. Serial crystallography, an experimental strategy that aggregates small pieces of data from a large uniform pool of crystals, has been demonstrated at synchrotrons and X-ray free-electron lasers. This work utilizes a microfluidic crystallization platform for serial Laue diffraction from macroscopic crystals and proposes that a collection of small slices of Laue data from many individual crystals is a realistic solution to the difficulties in dynamic studies of irreversible biochemical reactions. [ABSTRACT FROM AUTHOR]

Objective The hypothesis that sleeve gastrectomy (SG) is not associated with an increase in mucosal colorectal cancer (CRC) biomarkers, unlike Roux-en-Y gastric bypass (RYGB), was tested. Design and Methods Rectal mucosa, blood, and urine were obtained from morbidly obese patients ( n = 23) before and after (median 28 months) SG, as well as from nonobese controls ( n = 20). Rectal epithelial cell mitosis and apoptosis, crypt size/fission, and pro-inflammatory gene expression were measured, as well as systemic inflammatory biomarkers, including C-reactive protein (CRP). Results The mean pre-operative body mass index in SG patients was 65.7 kg/m2 (24.7 kg/m2 in controls). Mean excess weight loss post-SG was 38.2%. There was a significant increase in mitosis frequency, crypt size, and crypt fission (all P < 0.01) in SG patients versus controls, as well as evidence of a chronic inflammatory state (raised CRP and mononuclear cell p65 NFκB binding), but there was no significant change in these biomarkers after SG, except CRP reduction. Macrophage migration inhibitory factor mRNA levels were increased by 39% post-SG ( P = 0.038). Conclusions Mucosal biomarkers of CRC risk do not increase at 6 months following SG, unlike RYGB. Biomarkers of rectal crypt proliferation and systemic inflammation are increased in morbidly obese patients compared with controls. [ABSTRACT FROM AUTHOR]

The use of surface-based methods for the delivery of therapeutics has recently generated increasing interest. These platforms have tremendous potential to minimize detrimental side effects associated with systemic delivery by localizing the therapeutic vehicle, and thus provide higher local doses for improved efficacy. Cationic lipids are one of the most commonly used synthetic carriers for the delivery of genetic cargo, such as DNA and RNA. However, reports on the use of lipid-based films for gene delivery are scarce. Here we investigate the use of a lipid-based film for the in vitro delivery of plasmid DNA. Solid DNA-lipid films show very low levels of transfection, while identical complexes prepared for bolus delivery provide high levels of transfection when used directly. We investigate the mechanism, whereby the activity of these solid-state films is lost and suggest methods for circumventing these challenges and restoring the efficacy of these films as gene delivery platforms. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3203-3213, 2013 [ABSTRACT FROM AUTHOR]

OBJECTIVES: To investigate the prevalence of isolated urinary and fecal incontinence and double incontinence in community-living stroke survivors and to assess the degree of soiling. DESIGN: Community-based postal survey. SETTING: Leicestershire, United Kingdom. PARTICIPANTS: Sixty-four thousand seven hundred forty-nine community-dwelling residents (aged≥40) were randomly selected from the Leicestershire Health Authority register. Residents living in institutional settings were excluded. MEASUREMENTS: Respondents were asked about previous stroke, urinary and bowel symptoms, and general health and demographic details including age, sex, and ethnicity. Urinary incontinence was defined as leakage several times a month or more often. Major fecal incontinence was defined as soiling of underwear, outer clothing, furnishings, or bedding several times a month or more often. RESULTS: A 65% response rate to the postal survey was obtained, with the return of 39,519 eligible questionnaires; 4% (n=1,483) reported stroke. Five percent of stroke survivors reported major fecal incontinence, with 4.3% reporting fecal and urinary incontinence and 0.8% reporting isolated fecal incontinence. Major fecal incontinence was four and a half times as prevalent in stroke survivors as in the nonstroke population, and stroke survivors were also twice as likely to report soiling of furnishings or bedding. Functional limitations influence the presence of fecal incontinence in the stroke and nonstroke population. CONCLUSION: Fecal incontinence is common in stroke survivors, and the degree of soiling can be considerable. Future research needs to explore the effect fecal incontinence can have on the lives of stroke survivors and on how it can best be managed in those living in the community. [ABSTRACT FROM AUTHOR]

Objectives. The study investigated the association between anxiety and depression and urge incontinence and the direction of causal pathways between these variables. Design. A prospective longitudinal postal survey. Method. A random sample of women aged 40 years or more, registered with a general practitioner in Leicestershire or Rutland, was mailed a postal questionnaire. The questionnaire included questions on general health, urinary symptoms and the Hospital Anxiety and Depression Scale (HADS). In total, 12,568 women responded to the baseline postal survey (65.3% response rate) and 9,596 to the first annual follow-up (79.8% response rate). The prevalence and one-year incident rates of these symptoms were compared and contrasted, whilst controlling for confounding variables. Results. A significant proportion of women with urge incontinence reported symptoms of anxiety (56.6%) and depression (37.6%). Anxiety and depression were associated with a number of urinary symptoms and were not exclusive to urge incontinence. Incident cases of anxiety and depression were predicted by the presence of urge incontinence at baseline. Incident cases of urge incontinence were predicted by anxiety at baseline, but not depression. Anxiety, urge incontinence and frequency appeared to interact and exacerbate each other. Conclusions. The findings demonstrated the relevance of emotional factors in the development and maintenance of urge incontinence. Currently, assessment and treatment protocols for urge incontinence concentrate on physical symptoms and toilet behaviours. A more integrated psychological model of urge incontinence is proposed. [ABSTRACT FROM AUTHOR]

Ultrashort pulse lasers offer great promise for tissue resection with exceptional precision and minimal thermal damage. Surgery in the bowel requires high precision and minimal necrotic tissue to avoid severe complications such as perforation. The deployment of ultrashort lasers in minimally invasive or endoscopic procedures has been hindered by the lack of suitable optical fibres for high peak powers. However, recent developments of hollow core microstructured fibres provide potential for delivery of such pulses throughout the body. In this study, analysis of laser ablation via a scanning galvanometer on a porcine colon tissue model is presented. A thermally damaged region (<85 μm) and fine depth control of ablation using the pulse energies 46 and 33 μJ are demonstrated. It is further demonstrated that such pulses suitable for precision porcine colon resection can be flexibly delivered via a hollow core negative curvature fibre (HC‐NCF) and again ablation depth can be controlled with a thermally damaged region <85 μm. Ablation volumes are comparable to that of early stage lesions in the inner lining of the colon. This study concludes that the combination of ultrashort pulses and flexible fibre delivery via HC‐NCF present a viable route to new minimally invasive surgical procedures. [ABSTRACT FROM AUTHOR]