Few-cycle laser pulse characterization on-target using high-harmonic generation from nano-scale solids

We demonstrate high-harmonic generation for the time-domain observation of the electric field (HHG-TOE) and use it to measure the waveform of ultrashort mid-infrared (MIR) laser pulses interacting with ZnO thin-films or WS2 monolayers. The working principle relies on perturbing HHG in solids with a weak replica of the pump pulse. We measure the duration of few-cycle pulses at 3200 nm, in reasonable agreement with the results of established pulse characterization techniques. Our method provides a straightforward approach to accurately characterize femtosecond laser pulses used for HHG experiments right at the point of interaction.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Bowel Obstruction From Biliary Stent Migration: An Unusual Case of Abdominal Pain

Endoscopic biliary stent placement is an important procedure that is commonly done in patients with malignant obstruction of the biliary tree. However, it can also be done to relieve non-maligant obstructions short term until more curative surgical interventions can be performed. There are two main types of stents used for these procedures: self-expanding metal stents (SEMSs) and plastic stents. Each of these stent types has different indications, and determining the correct stent for each individual patient is important. Here, we present a case of a 73-year-old female who presented with abdominal pain due to small bowel obstruction caused by a dislodged biliary duct stent. We hope to promote more focus on selecting the right stent type for each patient and encouraging follow-up visits after placement, especially for those with a history of medical noncompliance.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Structural and electronic properties of MoS2 and MoSe2 monolayers grown by chemical vapor deposition on Au(111)

The exceptional electronic and photonic properties of the monolayers of transition metal dichalcogenides including the spin-orbit splitting of the valence and conduction bands at the K points of the Brillouin zone make them promising for novel applications in electronics, photonics and optoelectronics. Scalable growth of these materials and understanding of their interaction with the substrate is crucial for these applications. Here we report the growth of MoS2 and MoSe2 monolayers on Au(111) by chemical vapor deposition at ambient pressure as well as the analysis of their structural and electronic properties down to the atomic scale. To this aim, we apply ultrahigh vacuum surface sensitive techniques including scanning tunneling microscopy and spectroscopy, low-energy electron diffraction, X-ray and angle-resolved ultraviolet photoelectron spectroscopy in combination with Raman spectroscopy at ambient conditions. We demonstrate the growth of high-quality epitaxial single crystalline MoS2 and MoSe2 monolayers on Au(111) and show the impact of annealing on the monolayer/substrate interaction. Thus, as-grown and moderately annealed (<100 °C) MoSe2 monolayers are decoupled from the substrate by excess Se atoms, whereas annealing at higher temperatures (>250 °C) results in their strong coupling with the substrate caused by desorption of the excess Se. The MoS2 monolayers are strongly coupled to the substrate and the interaction remains almost unchanged even after annealing up to 450 °C.

Dental clinicians' perceptions on the use of tele-dentistry consultations during COVID-19 within public dental clinics in Sydney, Australia

BACKGROUND

Although well accepted by clinicians and patients, teledentistry is not currently a widely used model of care within Australian public oral health services. This qualitative study aimed to review and evaluate dental clinicians' perceptions, by determining the acceptability and appropriateness of teledentistry as a model of care.

METHODS

A purposive sample of 12 public dental practitioners employed by a Local Health District in Sydney, and who had participated in teledentistry consultations, were recruited to participate in focus groups. Focus group discussions were transcribed verbatim and subjected to thematic analysis.

RESULTS

Teledentistry was a novel concept for most participants and was well accepted. Participants valued the use of a standardized consultation template as well as effective communication with other dental clinicians to support the practice of teledentistry. However, many found attempting contact with patients over the telephone difficult as well as the perceived patient frustration with the administration process and technological difficulties experienced.

CONCLUSION

Teledentistry has the potential for growth and expansion in the public health system. From the opinions in this study, the authors propose further research is needed into the efficacy of teledentistry to assist with the development of a model of care that would be beneficial for dental clinicians and their patients. © 2023 Australian Dental Association.

Regulating Li-Ion Transport through Ultrathin Molecular Membrane to Enable High-Performance All-Solid-State-Battery

Solid-state lithium metal batteries with garnet-type electrolyte provide several advantages over conventional lithium-ion batteries, especially for safety and energy density. However, a few grand challenges such as the propagation of Li dendrites, poor interfacial contact between the solid electrolyte and the electrodes, and formation of lithium carbonate during ambient exposure over the solid-state electrolyte prevent the viability of such batteries. Herein, an ultrathin sub-nanometer porous carbon nanomembrane (CNM) is employed on the surface of solid-state electrolyte (SSE) that increases the adhesion of SSE with electrodes, prevents lithium carbonate formation over the surface, regulates the flow of Li-ions, and blocks any electronic leakage. The sub-nanometer scale pores in CNM allow rapid permeation of Li-ions across the electrode-electrolyte interface without the presence of any liquid medium. Additionally, CNM suppresses the propagation of Li dendrites by over sevenfold up to a current density of 0.7 mA cm-2 and enables the cycling of all-solid-state batteries at low stack pressure of 2 MPa using LiFePO4 cathode and Li metal anode. The CNM provides chemical stability to the solid electrolyte for over 4 weeks of ambient exposure with less than a 4% increase in surface impurities.

Kapitza-resistance-like exciton dynamics in atomically flat MoSe2-WSe2 lateral heterojunction

Being able to control the neutral excitonic flux is a mandatory step for the development of future room-temperature two-dimensional excitonic devices. Semiconducting Monolayer Transition Metal Dichalcogenides (TMD-ML) with extremely robust and mobile excitons are highly attractive in this regard. However, generating an efficient and controlled exciton transport over long distances is a very challenging task. Here we demonstrate that an atomically sharp TMD-ML lateral heterostructure (MoSe2-WSe2) transforms the isotropic exciton diffusion into a unidirectional excitonic flow through the junction. Using tip-enhanced photoluminescence spectroscopy (TEPL) and a modified exciton transfer model, we show a discontinuity of the exciton density distribution on each side of the interface. We introduce the concept of exciton Kapitza resistance, by analogy with the interfacial thermal resistance referred to as Kapitza resistance. By comparing different heterostructures with or without top hexagonal boron nitride (hBN) layer, we deduce that the transport properties can be controlled, over distances far greater than the junction width, by the exciton density through near-field engineering and/or laser power density. This work provides a new approach for controlling the neutral exciton flow, which is key toward the conception of excitonic devices.

CRAB score for prediction of colectomy within 2 years following admission for acute severe ulcerative colitis

Background

The Oxford and Swedish indexes were developed to predict in-hospital colectomy in acute severe ulcerative colitis (ASUC), but not long-term prediction, and all these indexes were based on Western data. Our study aimed to analyze the predictors of colectomy within 3 years of ASUC in an Indian cohort and derive a simple predictive score.

Methods

A prospective observational study was conducted in a tertiary health care center in South India over a period of 5 years. All patients admitted with ASUC were followed up for a period of 24 months after the index admission, to look for progression to colectomy.

Results

A total of 81 (47 male) patients were included in the derivation cohort. Fifteen (18.5%) patients required colectomy during a follow-up period of 24 months. On regression analysis, C-reactive protein (CRP) and serum albumin were independent predictors of 24-month colectomy. The CRAB (CRP + AlBumin) score was obtained by multiplying coefficient of beta to albumin and CRP (CRAB score = CRP x 0.2 - Albumin x 0.26). The CRAB score demonstrated an AUROC of 0.923 and a score of >0.4 with a sensitivity of 82% and specificity of 92% for the prediction of 2-year colectomy following ASUC. The score was validated in a validation cohort of 31 patients, and at >0.4, the score had a sensitivity of 83% and a specificity of 96% in predicting colectomy.

Conclusion

CRAB score is a simple prognostic score that can predict 2-year colectomy in ASUC patients with high sensitivity and specificity.

Interface engineering of charge-transfer excitons in 2D lateral heterostructures

The existence of bound charge transfer (CT) excitons at the interface of monolayer lateral heterojunctions has been debated in literature, but contrary to the case of interlayer excitons in vertical heterostructure their observation still has to be confirmed. Here, we present a microscopic study investigating signatures of bound CT excitons in photoluminescence spectra at the interface of hBN-encapsulated lateral MoSe₂-WSe₂ heterostructures. Based on a fully microscopic and material-specific theory, we reveal the many-particle processes behind the formation of CT excitons and how they can be tuned via interface- and dielectric engineering. For junction widths smaller than the Coulomb-induced Bohr radius we predict the appearance of a low-energy CT exciton. The theoretical prediction is compared with experimental low-temperature photoluminescence measurements showing emission in the bound CT excitons energy range. We show that for hBN-encapsulated heterostructures, CT excitons exhibit small binding energies of just a few tens meV and at the same time large dipole moments, making them promising materials for optoelectronic applications (benefiting from an efficient exciton dissociation and fast dipole-driven exciton propagation). Our joint theory-experiment study presents a significant step towards a microscopic understanding of optical properties of technologically promising 2D lateral heterostructures.

Tumour Microenvironment as a Potential Immune Therapeutic Target for Tongue Cancer Management

Immunotherapy is a promising approach in the management of human cancers and has been proven to provide a durable response in many cancers. It is helpful as an adjuvant therapy for cancers and at present is considered as a fourth pillar supporting surgery, chemotherapy and radiotherapy. In the treatment of oral cancer, immunotherapy is approved in late-stage diseases where surgical resection cannot be carried out or fails, leading to recurrences and metastasis. Evidences suggest that when given as a first-line treatment, it can elicit an immune response that shrinks tumours, which could provide long-term benefit for patients. But unlike the traditional approach which follows the uniform protocol for all oral cancer patients, effective immunotherapy requires a more site-specific personalized approach. The aim of this paper is to review the various immune evasive mechanisms adopted by tumour cells and their relevance as potential targets for immunotherapy in oral tongue squamous cell carcinoma.

Nanoscale friction on MoS2/graphene heterostructures

Stacked hetero-structures of two-dimensional materials allow for a design of interactions with corresponding electronic and mechanical properties. We report structure, work function, and frictional properties of 1 to 4 layers of MoS₂ grown by chemical vapor deposition on epitaxial graphene on SiC(0001). Experiments were performed by atomic force microscopy in ultra-high vacuum. Friction is dominated by adhesion which is mediated by a deformation of the layers to adapt the shape of the tip apex. Friction decreases with increasing number of MoS₂ layers as the bending rigidity leads to less deformation. The dependence of friction on applied load and bias voltage can be attributed to variations in the atomic potential corrugation of the interface, which is enhanced by both load and applied bias. Minimal friction is obtained when work function differences are compensated.

Charge-State-Enhanced Ion Sputtering of Metallic Gold Nanoislands

Experimental results on the charge-state-dependent sputtering of metallic gold nanoislands are presented. Irradiations with slow highly charged ions of metallic targets were previously considered to show no charge state dependent effects on ion-induced material modification, since these materials possess enough free electrons to dissipate the deposited potential energy before electron-phonon coupling can set in. By reducing the size of the target material down to the nanometer regime and thus enabling a geometric energy confinement, a possibility is demonstrated to erode metallic surfaces by charge state related effects in contrast to regular kinetic sputtering.

Germline-focused analysis of tumour-detected variants in 49,264 cancer patients: ESMO Precision Medicine Working Group recommendations

BACKGROUND

The European Society for Medical Oncology Precision Medicine Working Group (ESMO PMWG) was reconvened to update its 2018/19 recommendations on follow-up of putative germline variants detected on tumour-only sequencing, which were based on an analysis of 17 152 cancers.

METHODS

We analysed an expanded dataset including 49 264 paired tumour-normal samples. We applied filters to tumour-detected variants based on variant allele frequency, predicted pathogenicity and population variant frequency. For 58 cancer-susceptibility genes, we then examined the proportion of filtered tumour-detected variants of true germline origin [germline conversion rate (GCR)]. We conducted subanalyses based on the age of cancer diagnosis, specific tumour types and 'on-tumour' status (established tumour-gene association).

RESULTS

Analysis of 45 472 nonhypermutated solid malignancy tumour samples yielded 21 351 filtered tumour-detected variants of which 3515 were of true germline origin. 3.1% of true germline pathogenic variants were absent from the filtered tumour-detected variants. For genes such as BRCA1, BRCA2 and PALB2, the GCR in filtered tumour-detected variants was >80%; conversely for TP53, APC and STK11 this GCR was <2%.

CONCLUSION

Strategic germline-focused analysis can prioritise a subset of tumour-detected variants for which germline follow-up will produce the highest yield of most actionable true germline variants. We present updated recommendations around germline follow-up of tumour-only sequencing including (i) revision to 5% for the minimum per-gene GCR, (ii) inclusion of actionable intermediate penetrance genes ATM and CHEK2, (iii) definition of a set of seven 'most actionable' cancer-susceptibility genes (BRCA1, BRCA2, PALB2, MLH1, MSH2, MSH6 and RET) in which germline follow-up is recommended regardless of tumour type.

GRP78 promotes the osteogenic and angiogenic response in periodontal ligament stem cells

Periodontitis is a progressive disease that ultimately leads to bone and tooth loss. A major consequence of periodontal disease is the inability to regain lost bone in the periodontium. The importance was demonstrated of glucose-regulated protein-78 (GRP78) in the osteogenic differentiation of periodontal ligament stem cells and their potential use for regeneration of the periodontium. Previous studies have shown the relationship between GRP78 and dentine matrix protein-1 (DMP1). The importance of this receptor-ligand complex in supporting the process of osteogenesis and angiogenesis was confirmed in this study. To show the function of GRP78 in mineralised tissues, transgenic periodontal ligament stem cells (PDLSCs) were generated in which GRP78 was either overexpressed or silenced. Gene expression analysis of the cells cultured under osteogenic conditions showed an increase in key osteogenic genes with the overexpression of GRP78. RNA-Seq analysis was also performed to understand the transcriptome profile associated with genotype changes. Using the database for annotation, visualisation, and integration discovery (DAVID) for the functional enrichment analysis of differentially expressed genes, the upregulation of genes promoting osteogenesis and angiogenesis with GRP78 overexpression was demonstrated. Alizarin red staining and scanning electron microscopy analysis revealed matrix mineralisation with increased calcium deposition in GRP78 overexpressing cells. The in vivo osteogenic and angiogenic function of GRP78 was shown using a subcutaneous implantation rodent model. The results suggested that GRP78 in PDLSCs can regulate the expression of both osteogenesis and angiogenesis. Therefore, GRP78 could be considered as a therapeutic target for repair of diseased periodontium.

Self-assembly of CdSe 3D urchins and their photocatalytic response

Photocatalysis is found to be one of the best suited processes that respond to the purification of water systems and the semiconductor nanomaterials are learned to be incredible materials which carry out the photocatalytic process as they readily decompose the pollutants effectively. In this present work, CdSe nanoparticles belonging to II-VI group semiconductor compounds were synthesized using a facile hydrothermal process with different precursor concentrations and were analysed for various characterization studies such as X-ray diffraction (XRD), Transmission electron microscopy (TEM), UV-vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Photoluminescence (PL) studies. The XRD study of the synthesized CdSe nanostructures revealed that the average crystallite size was ranging from 18.5 nm to 24 nm pointing out the increase in size with increase in molar concentrations. The morphological structure of synthesized CdSe samples exhibited urchin-like structure for a lower concentration with several rod-like projections appearing in diverse directions. These CdSe nano-urchins synthesized with lower concentrations are found suitable to carry out the process of photocatalytic activity. The process was carried out under visible light radiation for 180 min with aqueous solution of methylene blue (MB) as the ideal toxin to be degraded. The attained degradation efficiency was nearly 80% clearly displaying that the synthesized samples are good photocatalysts. By tuning the bandgap, through the optimization of the precursor concentrations, greater efficiency can be achieved in future.

Exciton Dynamics in MoS2-Pentacene and WSe2-Pentacene Heterojunctions

We measured the exciton dynamics in van der Waals heterojunctions of transition metal dichalcogenides (TMDCs) and organic semiconductors (OSs). TMDCs and OSs are semiconducting materials with rich and highly diverse optical and electronic properties. Their heterostructures, exhibiting van der Waals bonding at their interfaces, can be utilized in the field of optoelectronics and photovoltaics. Two types of heterojunctions, MoS₂-pentacene and WSe₂-pentacene, were prepared by layer transfer of 20 nm pentacene thin films as well as MoS₂ and WSe₂ monolayer crystals onto Au surfaces. The samples were studied by means of transient absorption spectroscopy in the reflectance mode. We found that A-exciton decay by hole transfer from MoS₂ to pentacene occurs with a characteristic time of 21 ± 3 ps. This is slow compared to previously reported hole transfer times of 6.7 ps in MoS₂-pentacene junctions formed by vapor deposition of pentacene molecules onto MoS₂ on SiO₂. The B-exciton decay in WSe₂ shows faster hole transfer rates for WSe₂-pentacene heterojunctions, with a characteristic time of 7 ± 1 ps. The A-exciton in WSe₂ also decays faster due to the presence of a pentacene overlayer; however, fitting the decay traces did not allow for the unambiguous assignment of the associated decay time. Our work provides important insights into excitonic dynamics in the growing field of TMDC-OS heterojunctions.

Signatures of Multiband Effects in High-Harmonic Generation in Monolayer MoS_{2}

High-harmonic generation (HHG) in solids has been touted as a way to probe ultrafast dynamics and crystal symmetries in condensed matter systems. Here, we investigate the polarization properties of high-order harmonics generated in monolayer MoS_{2}, as a function of crystal orientation relative to the mid-infrared laser field polarization. At several different laser wavelengths we experimentally observe a prominent angular shift of the parallel-polarized odd harmonics for energies above approximately 3.5 eV, and our calculations indicate that this shift originates in subtle differences in the recombination dipole strengths involving multiple conduction bands. This observation is material specific and is in addition to the angular dependence imposed by the dynamical symmetry properties of the crystal interacting with the laser field, and may pave the way for probing the vectorial character of multiband recombination dipoles.

Patterned Growth of Transition Metal Dichalcogenide Monolayers and Multilayers for Electronic and Optoelectronic Device Applications

A simple, large area, and cost-effective soft lithographic method is presented for the patterned growth of high-quality 2D transition metal dichalcogenides (TMDs). Initially, a liquid precursor (Na₂ MoO₄ in an aqueous solution) is patterned on the growth substrate using the micromolding in capillaries technique. Subsequently, a chemical vapor deposition step is employed to convert the precursor patterns to monolayer, few layers, or bulk TMDs, depending on the precursor concentration. The grown patterns are characterized using optical microscopy, atomic force microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, and photoluminescence spectroscopy to reveal their morphological, chemical, and optical characteristics. Additionally, electronic and optoelectronic devices are realized using the patterned TMDs and tested for their applicability in field effect transistors and photodetectors. The photodetectors made of MoS₂ line patterns show a very high responsivity of 7674 A W^-1 and external quantum efficiency of 1.49 × 10⁶ %. Furthermore, the multiple grain boundaries present in patterned TMDs enable the fabrication of memtransistor devices. The patterning technique presented here may be applied to many other TMDs and related heterostructures, potentially advancing the fabrication of TMDs-based device arrays.

Chemical Vapor Deposition of High-Optical-Quality Large-Area Monolayer Janus Transition Metal Dichalcogenides

One-pot chemical vapor deposition (CVD) growth of large-area Janus SeMoS monolayers is reported, with the asymmetric top (Se) and bottom (S) chalcogen atomic planes with respect to the central transition metal (Mo) atoms. The formation of these 2D semiconductor monolayers takes place upon the thermodynamic-equilibrium-driven exchange of the bottom Se atoms of the initially grown MoSe₂ single crystals on gold foils with S atoms. The growth process is characterized by complementary experimental techniques including Raman and X-ray photoelectron spectroscopy, transmission electron microscopy, and the growth mechanisms are rationalized by first principle calculations. The remarkably high optical quality of the synthesized Janus monolayers is demonstrated by optical and magneto-optical measurements which reveal the strong exciton-phonon coupling and enable an exciton g-factor of -3.3.

Ion-Induced Surface Charge Dynamics in Freestanding Monolayers of Graphene and MoS_{2} Probed by the Emission of Electrons

We compare the ion-induced electron emission from freestanding monolayers of graphene and MoS_{2} to find a sixfold higher number of emitted electrons for graphene even though both materials have similar work functions. An effective single-band Hubbard model explains this finding by a charge-up in MoS_{2} that prevents low energy electrons from escaping the surface within a period of a few femtoseconds after ion impact. We support these results by measuring the electron energy distribution for correlated pairs of electrons and transmitted ions. The majority of emitted primary electrons have an energy below 10 eV and are therefore subject to the dynamic charge-up effects at surfaces.

Tuning nanowire lasers via hybridization with two-dimensional materials

Mixed-dimensional hybrid structures have recently gained increasing attention as promising building blocks for novel electronic and optoelectronic devices. In this context, hybridization of semiconductor nanowires with two-dimensional materials could offer new ways to control and modulate lasing at the nanoscale. In this work, we deterministically fabricate hybrid mixed-dimensional heterostructures composed of ZnO nanowires and MoS₂ monolayers with micrometer control over their relative position. First, we show that our deterministic fabrication method does not degrade the optical properties of the ZnO nanowires. Second, we demonstrate that the lasing wavelength of ZnO nanowires can be tuned by several nanometers by hybridization with CVD-grown MoS₂ monolayers. We assign this spectral shift of the lasing modes to an efficient carrier transfer at the heterointerface and the subsequent increase of the optical band gap in ZnO (Moss-Burstein effect).

Post-load glucose spike: a better predictor of post-MI prognosis than post-load glucose in patients without known diabetes

Funding Acknowledgements

Type of funding sources: None.

Background

In non-diabetic population, number of deaths increase as the post-challenge glucose spike (PGS) i.e. difference between the fasting and 2h-PG increases in the DECODE study.

Purpose

To assess whether PGS is a better predictor of post-ACS prognosis in patients without known diabetes.

Methods

Retrospective cohort analysis of post-MI survivors (n=1056) without known diabetes undergoing pre-discharge oral glucose tolerance test. A standardised dataset was collected for the Myocardial Infarction National Audit Project. MACE (death or non-fatal re-infarction) over 5 (median 3.4) years was collected from notes review. Predictors of MACE were determined from Cox proportional hazard regression (stepwise) models adjusted for several variables (tested for collinearity) including GRACE score (GRS), fasting (FG) and 2-hour post-load glucose (2hG) and PGS as % of the 2hG (%PGS) (VIF=3.12). Incremental predictive value of PGS over 2hG was tested using probabilities of MACE calculated from logistic regression models using the same covariates and FG, 2hG and PGS individually and in combination applying c-statistics, continuous net reclassification improvement (cNRI) and integrated discrimination improvement (IDI).

Results

Of the patients 469 (44.4%) had normal glucose tolerance, 378(35.8%) preDM and 209 (19.8%) had new DM. In the whole cohort, MACE was predicted by %PGS (HR 1.02 (1.01-1.03), p&lt;0.0001), GRS (HR 1.01, (1.01-1.02), p&lt;0.0001), discharge with betablockers (HR 1.50 (1.14-1.98), p=0.0037), previous history of MI (HR 1.44 (1.02-2.03), p=0.039) but neither FG nor 2hG were included in the final model. MACE was predicted by %PGS (HR 1.04 (1.02-1.06), p&lt;0.0001) in the non-diabetic group but not in the new DM patients (HR 1.02 (0.99-1.05), p=0.296). Addition of PGS to models containing FG and 2hG improved reclassification by 22.6% for events and 5.0% for non-events (NRI&gt;0 0.275, p&lt;0.001) and discrimination (IDI 0.0076, p=0.033). However the c-statistics did not change significantly (ΔAUC 0.0094, p=0.099).

Conclusion

PGS is a better predictor of post-MI prognosis than FG or 2hG in patients without known diabetes.

Elliptical and linear relationships with rumen temperature support a homeorhetic trajectory for DMI during recovery of feedlot cattle exposed to moderate heat load

Most feedlot animals in Australia experience 2 to 3 moderate heat waves during summer. This study aimed to gain understanding of the physiological drivers in response to and during recovery from such events with a view to designing strategies to ensure rapid and safe recovery. Two hypotheses were tested during thermal challenge and recovery in climate-controlled rooms (CCR): firstly, the feedlot steer on a grain-based diet mounts appropriate physiological responses during moderate heat load and in recovery so that its performance and physiology state after recovery is not different to the feed restricted thermoneutral (FRTN) steer. Secondly, commonly used indicators of increased heat load, e.g., respiration rate (RR), panting score (PS), body surface temperatures (ST), and water consumption (WC), reflect rumen temperature (RT) during thermal challenge and recovery at the level of daily means. In this study, 36 Angus steers (live weight (LW) 451.5 ± 22.6 kg) made up 3 cohorts of 12 animals that sequentially underwent the CCR phase. For this 18-d phase, the steers were allocated to either a moderate heat load treatment (thermally challenged, TC, n = 18) or a FRTN treatment (n = 18). The TC group underwent 3 periods, Pre-Challenge (4 d, temperature humidity index (THI) range of 68 to 71), Challenge (7 d, THI 73 to 84 with diurnal cycling), and Recovery (7 d, THI 68 to 71). The FRTN group were held at thermoneutral conditions in the CCR (THI 66.9 ± 0.3), and each animal was offered an amount of feed was based on the feed intake of its LW matched TC pair. Thus, as DMI fell in the TC group during Challenge, feed restriction was imposed on the FRTN group. The data were collected by trained observers were DMI, RT, RR, PS, body STs (forehead, shoulder, leg, rump), and WC. Challenge induced a heat stress response in the TC group with reduced DMI and LW, and elevated RT, RR, PS, body STs, and WC (P < 0.001). These measures were unchanged or reduced in the FRTN group (P < 0.001). At the end of Recovery, the TC and FRTN groups had converged on most measures including LW. Daily mean RT of both groups showed strong linear relationships with THI, RR, PS, head ST, and WC (P ≤ 0.0022) but opposing elliptical relationships with DMI; that is, as DMI fell with increasing RT for the TC group, DMI increased with rising RT for the FRTN group. In all, the feedlot steers in this study demonstrated sufficient homeorhetic capacity to adjust to moderate heat load and recover from it.

Post-Partum Spontaneous Coronary Artery Dissection with Occluded Left Anterior Descending Artery

Presentation We present a case of spontaneous coronary artery dissection (SCAD) in a 35-year-old lady who was 4 months post-partum. Despite a lack of typical risk factors, initial presentation and investigations were strongly suggestive of ACS. Diagnosis Coronary angiography revealed an occluded proximal left anterior descending (LAD) artery with TIMI 0 flow. Angiographic appearances and intravascular ultrasound (IVUS) were consistent with SCAD. Treatment A single drug-eluting stent was deployed, successfully restoring good flow, without extending the dissection flap. Discussion SCAD should be considered as an important and underdiagnosed cause of ACS, predominantly in young women without other apparent risk factors.

325 Improving the Documentation in the Consent Form for Patients Lacking Capacity: A Completed Audit Cycle

Aim

According to GMC guidance, we are bound to discuss with close members of the patients to consider their views and reach the consensus of clinical management when patients lack capacity to make decisions. Our audit aimed to compare the practice of our institution against this guidance and instigate changes as necessary.

Method

We collected data of 30 randomly selected patients with dementia, undergoing emergency orthopaedic operations, from February to April 2021 in the first cycle. The data were collected from medical notes prospectively. The findings were presented in the local meeting. The implementations involved raising awareness of the GMC guidance among the members of the Trauma & Orthopaedics team by organizing a teaching session, creating posters, and sending an email from the clinical lead to the staff members to highlight the audit result. It was followed by the second audit cycle, which included 40 patients from June to August 2021.

Results

The first cycle revealed that there was only 36% compliance to the GMC guidance in our department, since only 9 out of the 30 cases had documentation about the discussion with the appropriate family member. The compliance rate of the second cycle (40 patients) saw a huge improvement up to 83%.

Conclusions

Significant improvement in documentation of the socially and medicolegally important discussion with the close contact of the patient was achieved. This was done by identifying the area which needed improvement and instigating changes in our department. Further audit loops will be conducted in due course to sustain this achievement.

Dentine matrix metalloproteinases as potential mediators of dentine regeneration

Matrix metalloproteinases (MMPs) have been implicated not only in the regulation of developmental processes but also in the release of biologically active molecules and in the modulation of repair during tertiary dentine formation. Although efforts to preserve dentine have focused on inhibiting the activity of these proteases, their function is much more complex and necessary for dentine repair than expected. The present review explores the role of MMPs as bioactive components of the dentine matrix involved in dentine formation, repair and regeneration. Special consideration is given to the mechanical properties of dentine, including those of reactionary and reparative dentine, and the known roles of MMPs in their formation. MMPs are critical components of the dentine matrix and should be considered as important candidates in dentine regeneration.

824 UK CoPACK Study: Health Care Workers Knowledge and Confidence in Using Personal Protective Equipment (PPE) And Related Anxiety Levels During The COVID-19 Pandemic

Aim

The COVID-19 pandemic has resulted in significant pressures on the NHS. Healthcare workers (HCWs) are at increased risk of infection. Personal protective equipment (PPE) lowers the risk of infection transmission. However, during the early phases of the pandemic, the information available regarding COVD-19 and the use of PPE has been unclear, with constantly changing guidelines. The aim of this study was to determine the knowledge and confidence about PPE usage among HCWs, in addition to measuring their anxiety levels during the COVID pandemic.

Method

A validated questionnaire was distributed among HCWs in as many UK hospitals as possible, during April 2020. The questionnaire consisted of 13 questions regarding demographics, knowledge on PPE guidance, HCW training and confidence levels in PPE usage and finally anxiety levels measured using the GAD-7 psychometric tool.

Results

1055 responses were received. Nurses (49%), Healthcare Assistants (HCA - 20%), Doctors (17%), Physios (8%) and other (6%). 99% of respondents indicated they were familiar with PPE guidance, but only 1.6% answered all 3 questions on PPE guidance accurately. 86.4% of respondents received mask-fitting checks. 79.7% received donning-doffing training. Despite this, only 46.8% were confident on their familiarity with PPE. 32.5% felt that their hospital communication regarding PPE policy during COVID-19 pandemic was poor or very poor. 30% HCWs experienced severe anxiety.

Conclusions

National guidance and local training on PPE usage during the COVID-19 pandemic has been unsatisfactory, leading to higher anxiety among HCWs. Improved information delivery and training are essential in preparation for the second wave and future pandemics.

586 Peri-Pancreatic Migration of Lost Intra Uterine Device: Case Report and Review of Literature

Intra uterine devices (IUDs) is one of the most effective form of contraception available today. Uterine perforation and IUD migration is a rare but serious complication and is reported to occur in 0.05 to 13 cases out of 1000 IUCD placements. Migration of IUD to pelvis and lower abdominal organs following uterine perforation has been reported widely in literature. However far migration into the upper abdomen in very rare. Here we report a case asymptomatic peri-pancreatic migration of IUD.

A 65-year-old lady being investigated for pneumonia was picked up to have an asymptomatic IUD lying in front of the pancreas. The patient recalled having a hormonal Mirena coil placed 12 years previously for menopausal symptoms. Routine 3-year general practitioner follow-up failed to detect the IUD on vaginal examination. The patient denied spontaneous IUD discharge. However, three subsequent pelvic ultrasound scans did not detect any retained IUD and she was discharged as unrecognized IUD expulsion. She remained asymptomatic for the next 12 years with no abdominal symptoms though she did report to the General Practitioner, multiple episodes of new onset hot flushes when opening bowels - which was managed conservatively with reassurance.

It was decided to surgically remove the IUD. Intraoperatively, the IUD was found densely adherent to the lesser omentum close to the pancreas and stomach and was removed safely laparoscopically. The patient made a good postoperative overnight recovery and was discharged.

Intra-abdominal migration of IUDs is a very rare complication of IUD insertion and when detected should be promptly treated with Laparoscopic removal.

Biomineralization of Enamel and Dentin Mediated by Matrix Proteins

Biomineralization of enamel, dentin, and bone involves the deposition of apatite mineral crystals within an organic matrix. Bone and teeth are classic examples of biomaterials with unique biomechanical properties that are crucial to their function. The collagen-based apatite mineralization and the important function of noncollagenous proteins are similar in dentin and bone; however, enamel is formed in a unique amelogenin-containing protein matrix. While the structure and organic composition of enamel are different from those of dentin and bone, the principal molecular mechanisms of protein-protein interactions, protein self-assembly, and control of crystallization events by the organic matrix are common among these apatite-containing tissues. This review briefly summarizes enamel and dentin matrix components and their interactions with other extracellular matrix components and calcium ions in mediating the mineralization process. We highlight the crystallization events that are controlled by the protein matrix and their interactions in the extracellular matrix during enamel and dentin biomineralization. Strategies for peptide-inspired biomimetic growth of tooth enamel and bioinspired mineralization of collagen to stimulate repair of demineralized dentin and bone tissue engineering are also addressed.

Energy-Level Alignment at Interfaces between Transition-Metal Dichalcogenide Monolayers and Metal Electrodes Studied with Kelvin Probe Force Microscopy

We studied the energy-level alignment at interfaces between various transition-metal dichalcogenide (TMD) monolayers, MoS₂, MoSe₂, WS₂, and WSe₂, and metal electrodes with different work functions (WFs). TMDs were deposited on SiO₂/silicon wafers by chemical vapor deposition and transferred to Al and Au substrates, with significantly different WFs to identify the metal-semiconductor junction behavior: oxide-terminated Al (natural oxidation) and Au (UV-ozone oxidation) with a WF difference of 0.8 eV. Kelvin probe force microscopy was employed for this study, based on which electronic band diagrams for each case were determined. We observed the Fermi-level pinning for MoS₂, while WSe₂/metal junctions behaved according to the Schottky-Mott limit. WS₂ and MoSe₂ exhibited intermediate behavior.

155 Audit of Functional Outcome of Mason and Molloy Type 2 Posterior Malleolar Ankle Fractures Treated with Open Reduction and Internal Fixation Using A Posterolateral Approach

Introduction

It has been shown that direct fixation of the posterior malleolus improves functional outcomes. Our aim was to audit the functional outcome of patients with these fractures which were fixed with an isolated posterolateral approach.

Method

A consecutive case series of patients who underwent direct fixation of the posterior malleolus using a posterolateral approach between 20/12/2012 and 23/1/2020 was identified. Fractures were classified according to Mason and Molloy classification based on preoperative CT. Type 2a and 2b fractures were included. Functional outcome was assessed using Olerud-Molander score.

Result

18 patients were included. Mean age at time of surgery was 52 years (range 20 to 75 years). 56% (n = 10) were female. Mean follow up was 18.1 months (range 4.2 months to 7.2 years). OMAS score for type 2a fractures (n = 9) was 71.1 (95% CI 65.3 to 77.0). OMAS score for type 2b fractures (n = 9) was 67.8 (95% CI 54.6 to 81.0). There was no significant difference between groups (p = 0.65).

Conclusions

Fixation of Mason and Molloy Type 2 fractures using an isolated posterolateral approach results in satisfactory functional results for the majority of patients. Further prospective comparative study is needed to identify which patients benefit most from alternative approaches.

Post-load glucose spike is a determinant of post-MI prognosis in patients without known or newly diagnosed diabetes

Background

Post-prandial plasma glucose spikes contribute to the progression of atherosclerosis. Glycaemic variability may predict post-ACS prognosis. A third to two-thirds of these patients had diabetes mellitus (DM). Post-ACS prognosis is worse in DM than in those without. This has not been tested in patients without DM.

Purpose

To test whether post-load spike in plasma glucose in patients without known or newly diagnosed DM adversely affects prognosis.

Methods

Retrospective cohort analysis of 847 MI survivors without known or newly diagnosed DM who were followed up for MACE (death and non-fatal MI). The median post-glucose spike (PGS, defined as the difference between the 2h-PG and FPG) was 2.4 mmol/l for the whole cohort and 1.5 mmol/l for the patients with normal glucose tolerance (NGT). Group 1: PGS ≤2.4 mmol/l and Group 2: PGS &gt;2.4 mmom/l were compared using Mann-Whitney test for continuous variables and chi-squared test for categorical variables. Event free survival in the two groups was estimated from the Kaplan–Meier curves and compared using log-rank test. Cox proportional hazard regression identified predictors of MACE. Continuous net reclassification improvement (NRI&gt;0) and integrated discrimination improvement (IDI) and c-statistics determined the added predictive value of glycaemic matrices

Results

MACE was higher in group 2 (OR 1.99, 95% CI 1.36 to 2.91, p=0.0004) compared to group 1. In patients with NGT, MACE was higher in patients with PGS ≥1.5 mmol/l vs those below (OR 2.37, 95% CI 1.31 to 4.26, p=0.0041). Event free survival was worse in pre-diabetes than in the NGT groups (HR 1.57, 95% CI 1.17 to 2.12, p=0.003). and in group 2 than 1 (HR 2.01, 95% CI 1.49 to 2.71, p&lt;0.001). Amongst the patients with NGT, event free survival was worse in patients with PGS ≥1.5 mmol/l (HR 2.09, 95% CI 1.35 to 3.25, p&lt;0.001). PGS independently predicted MACE in the whole cohort (HR 1.16, 95% CI 1.06 to 1.26, p=0.002) and NGT group (HR 2.06, 95% 1.51 to 2.79, p&lt;0.000). Group 2 independently predicted MACE in the whole cohort (HR 1.75, 95% CI 1.26 to 2.42, p&lt;0.001). In the NGT group, PGS &gt;median, independently predicted of MACE (HR 2.67, 95% CI 1.54 to 4.61, p&lt;0.001). The c-statistic a model containing GRS only increased on addition of PGS (δAUC 0.0134, p=0.046) but not on addition of FPG. Within the whole cohort, PGS improved the net reclassification by 28% when added to the model containing GRS only. NGT cohort had higher net improvement at 46.6%. Addition of PGS to the model containing GRS and FPG resulted in NRI&gt;0 of 25.5% in the whole cohort and 56.3% in the NGT cohort. Similar changes were seen in the IDI.

Conclusion(s)

PGS predicts post MI prognosis in patients without known or newly diagnosed DM including in patients with NGT. This suggests that PGS is a more powerful indicator of post-MI prognosis than FPG

Funding Acknowledgement

Type of funding source: None

Scalable Functionalization of Optical Fibers Using Atomically Thin Semiconductors

Atomically thin transition metal dichalcogenides are highly promising for integrated optoelectronic and photonic systems due to their exciton-driven linear and nonlinear interactions with light. Integrating them into optical fibers yields novel opportunities in optical communication, remote sensing, and all-fiber optoelectronics. However, the scalable and reproducible deposition of high-quality monolayers on optical fibers is a challenge. Here, the chemical vapor deposition of monolayer MoS₂ and WS₂ crystals on the core of microstructured exposed-core optical fibers and their interaction with the fibers' guided modes are reported. Two distinct application possibilities of 2D-functionalized waveguides to exemplify their potential are demonstrated. First, the excitonic 2D material photoluminescence is simultaneously excited and collected with the fiber modes, opening a novel route to remote sensing. Then it is shown that third-harmonic generation is modified by the highly localized nonlinear polarization of the monolayers, yielding a new avenue to tailor nonlinear optical processes in fibers. It is anticipated that the results may lead to significant advances in optical-fiber-based technologies.

Does high-normal 2-hour post load plasma glucose after myocardial infarction in patients with normal glucose tolerance adversely affect prognosis?

Background

Type 2 diabetes mellitus (DM) and pre-DM, newly diagnosed after MI in patients without known DM adversely affects prognosis. 2-hour post-load glucose (2h-PG) predicts post-MI prognosis better than fasting plasma glucose (FPG). Plasma glucose below the conventional threshold for the diagnosis of impaired fasting glucose (IFG) and impaired glucose tolerance (IGT), affects post-MI prognosis.

Purpose

To test whether high-normal post-load plasma glucose in patients with normal glucose tolerance (NGT) would affect post-MI prognosis and whether FPG or 2h-PG increases this risk.

Methods

Retrospective cohort analysis of 425 MI survivors without known DM and with NGT followed up for (death and non-fatal MI) as MACE. MACE in patients with 2h-PG &gt; median for the whole cohort (Group 2), was compared with those at or below (Group 1). Event free survival in the two groups was estimated from the Kaplan–Meier curves and compared using log-rank test. Cox proportional hazard regression identified predictors of MACE. Continuous net reclassification improvement (NRI&gt;0) and integrated discrimination improvement (IDI) and c-statistics determined the added predictive value of glycaemic matrices.

Results

Median 2h-PG was 6.3 mmol/l. 219 patients in Group 1 and 206 in Group 2. Group 2 had higher age, prevalence of hypertension, hypercholesterolaemia, ST-segment depression and higher heart rate and GRACE scores. Median follow-up was 40.6 months. MACE was more frequent in Group 2 than Group 1 (OR 2.82, 95% CI 1.55 to 5.16, p&lt;0.001). MACE-free survival was higher in Group 1 (HR 2.43, 95% CI 1.53 to 3.85, p&lt;0.001). Group 2 (HR 2.42, 95% CI 1.44 to 4.04, p&lt;0.001) predicted the MACE-free survival. 2h-PG, but not the FPG independently predicted of MACE (HR 1.73, 95% CI 1.31 to 2.30, p&lt;0.001). Addition of 2h-PG to models containing FPG and other variables improved their predictive performance (NRI&gt;0 0.5062, p&lt;0.001; IDI 0.0376, p=0.003). The c-statistic increased when 2h-PG was added to the GRACE score only model (δAUC 0.037, 95% CI 0.012 to 0.081, p=0.046).

Conclusion(s)

This study suggests that “high-normal” 2h-PG is an independent predictor of post-MI prognosis. Normoglycaemic patients with 2h-PG ≥6.4 mmol/l, had worse post-MI prognosis compared to those with 2h-PG ≤6.3 mmol/l. The risk of MACE increased with increasing 2h-PG within the normal range. FPG had no effect on prognosis.

Funding Acknowledgement

Type of funding source: None

Does the endotracheal tube cuff pressure increases with transesophageal probe insertion?

Context:

The cuff pressure (CP) of the endotracheal tube (ETT) exceeding 30 cm of H₂O results in reduced perfusion of lateral mucosa of trachea leading to complications. As the posterior tracheal wall is in contact with the esophagus, there is a possibility that the insertion of transesophageal echo (TEE) probe may compress the tracheal wall and increase CP.

Aims:

This study was aimed to assess the impact of TEE probe insertion on CP in adults undergoing cardiac surgery.

Settings and Design:

Prospective observational study of 65 patients at tertiary care level hospital.

Subjects and Methods:

After balanced general anesthesia, patients were intubated with high volume low-pressure ET.TEE probe was then inserted with gentle jaw thrust. CP was measured by standard invasive pressure monitoring device at four points: T1 at baseline before TEE probe insertion; T2 maximum CP noted at TEE probe insertion; T3 at 5 min post TEE probe insertion; and T4 at post-TEE exam.

Statistical Analysis Used:

CP was compared between pairs of time points (T1 vs. T2; T1 vs. T3; and T1 vs. T4) using Mann-Whitney U test. Factors predicting CP >30 cm of H₂O at T4 were assessed by backward stepwise regression.

Results:

CP (mean ± S.D.) at T1, T2, T3, and T4 was 22 ± 3, 38 ± 10, 30 ± 6, and 30 ± 7, respectively. CP increased significantly from T1 to T2 (P < 0.001), T1 to T3 (P < 0.001), and T1 to T4 (P < 0.001). There were 26 patients (40%) with CP >30 cm of H₂O at end of TEE exam (T4). On multivariate analysis baseline, CP (T1) >20 cm of H₂O was significantly associated with CP >30 cm of H₂O at end of TEE exam with Odd's Ratio (OR) of 8.5 (1.76–41.06, P = 0.008).

Conclusions:

To conclude, the CP increases significantly with TEE probe insertion in 40% of patients exceeding a safe limit of 30 cm of H₂O. The monitoring and optimization of CP is advisable.