Incident pulmonary hypertension in 13,448 cases investigated with repeat echocardiography: insight from the National Echo Database of Australia (NEDA)

Background

We addressed the paucity of data describing the characteristics and natural history of incident pulmonary hypertension (PHT).

Methods

In this observational clinical cohort study, we examined 85,173 individuals undergoing routine echocardiography for heart disease without evidence of PHT (according to estimated right ventricular systolic pressure, eRVSP <30 mmHg). Subsequent age and sex-specific incidence of PHT were derived from repeat echocardiograms conducted a median of 3.43 (interquartile range, IQR 1.49 to 6.55) years apart in 13,448 adults. Progressive PHT severity with individual data linkage to all-cause mortality were examined per PHT stage: eRVSP 30–39 mmHg (mild PHT), 40–49 mmHg (moderate PHT) and ≥50 mmHg (severe PHT).

Results

A total of 6,169 men (45.9%, mean age 61.4±16.7 years) and 7,279 women (60.8±16.9 years) with no initial evidence of PHT were identified (first echocardiogram). Subsequently, 5,412 (40.2%,) developed PHT (repeat echocardiogram) – comprising 4,125 (30.7%, 65.0±14.3 years), 928 (6.9%, 69.2±13.5 years), and 359 (2.7%, 69.8±12.7 years) cases of mild, moderate, and severe PHT, respectively. The incidence of all stages of PHT was 15.2 cases per million men/annum and 12.5 cases per million women/annum. Overall, median eRVSP increased by +7.4 (IQR +4.6 to +10.1) and +30.7 (IQR +26.0 to +37.3) mmHg; median E:e' ratio increased by +1.0 (IQR −0.4 to +3.2) and +3.6 (IQR +2.0 to +8.2); and median LA volume increased by +5.0 (IQR +0.0 to +12.0) and +19.5 (IQR +9.0 to +31.0) ml/m2, respectively, in mild and severe PHT groups between first and last echocardiograms. During subsequent median 8.1 years follow-up, 2,776/13,448 (20.6%) individuals died from all-cause. Compared to no PHT, the age- and sex-adjusted hazard ratios for all-cause mortality increased to 1.35 (95% confidence interval, CI 1.23–1.47) in mild PHT, 1.94 (95% CI 1.73–2.18) in moderate PHT, and 2.43 (95% CI 2.09–2.83) in severe PHT (all p<0.001).

Conclusions

New onset of PHT is a common finding among individuals with heart disease followed-up with echocardiography. Even milder stage of PHT is associated with higher mortality, reinforcing the need for proactive evaluation for symptoms consistent with PHT.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Johnson & Johnson: Investigator-initiated grant

Counting the cost of progressive aortic valve stenosis: an international observational clinical cohort study

Background

We sought, for the first time, to quantify the societal to healthcare burden associated with the entire spectrum of aortic stenosis (AS) - the most common cardiac valve disorder requiring clinical management.

Methods

In this observational clinical cohort study with individual data linkage to all-cause mortality, we examined the distribution of progressive stenosis in the native aortic valves of 98,565 men and 99,357 women aged ≥65 years within a multicentre cohort across 24 sites internationally. Individuals were grouped according to their peak aortic valve velocity on last electrocardiogram investigation: 1.0–1.99 m/s (no AS/reference groups) and then 0.5 m/s increments up to ≥4.0 m/s (severe AS). Sex-specific premature mortality and years of life-lost (YLL) during 5-year follow-up were calculated, along with willingness-to-pay (WTP) to regain quality-adjusted life-years (QALYs) and healthcare costs associated with concurrent heart failure (HF).

Results

Overall, 20,701 men (21.0%; 95% CI 20.8–21.3) and 18,576 women (18.7%; 95% CI 18.5–18.9) had AS at baseline. Five-year mortality in men and women with no AS was 38.6% and 36.8%, respectively. In both sexes, mortality rose from 46.8–49.0% to 59.5–65.7% in the least- to most-severe cases of AS. Premature mortality (53.5–59.1% in the no AS group) declined from 42.4–50.9% to 34.8–35.2% of all deaths. Per 1,000 individuals, AS in men and women was associated with 8 and 13 more premature deaths resulting in 36 and 62 more QALYs (societal cost of $AU1.54 and $AU2.68 million respectively) when compared to no AS. The additional 5-year cost of healthcare utilisation for the 25 and 35 more men and women with concurrent HF and AS was estimated to be $AU1.27 and $AU1.91 million, respectively.

Conclusions

The presence of any degree of aortic valve stenosis is associated with higher levels of premature mortality coupled with excess healthcare costs that impose a heavy societal burden. These findings indicate the need for proactive and cost-effective strategies to promptly detect this common condition.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Edwards LifeSciences: Investigator-initiated grant

Identifying barriers to care for complex airway disease and multidisciplinary solutions to optimize therapy in Canada

Background

Complex airway disease such as Chronic Rhinosinusitis with Asthma or Aspirin Exacerbated Respiratory Disease requires a multidisciplinary approach to management and treatment. Many centers in the USA have created collaborative multidisciplinary clinics to support the management of these patients; however, similar structures do not appear to exist in Canada.

Methods

This mixed methods study used a combination of structured interviews and a cross-sectional national survey. Interviewees included members of the Canadian Rhinology Working Group and survey participants were a combination of academic and community Rhinologists, Respirologists and Allergists. All participation was voluntary and selection criteria was based on their involvement in treating complex airway disease. Our objective was to identify the current state of diagnosis and treatment of complex airway patients in Canada between Rhinology, Respirology and Allergy and understand the barriers, challenges and propose solutions to establishing a multidisciplinary airway clinic in Canada.

Results

Four Rhinologists participated in qualitative interviews and a convenience sample of 42 specialists through our known network responded to our quantitative survey. From our survey, 54.8% believed multidisciplinary clinics were necessary in the management of complex airway disease, providing better outcomes and cost-savings (69%, 45.2%). Most specialties agreed that history, physical, pulmonary function and skin prick testing was important for diagnosis (92.9%, 92.9%, 88.1%). If clinicians were to participate in a multidisciplinary clinic, they would be willing to forego an average of 14.2% of their mean daily income for that clinic. The ideal clinic location was split between a neutral shared location vs. a Rhinology clinic space (38.1%, 45.2%).

Conclusions

Complex airway diseases are currently managed in subspecialty silos resulting in fragmented care. Our study highlights gaps in management, areas for improvement and support for establishing multidisciplinary complex airway disease clinics in Canada to better treat this population.

2D-Oriented Attachment of 1D Colloidal Semiconductor Nanocrystals via an Etchant

The oriented attachment (OA) of 0D semiconductor nanocrystals into 1D and 2D nanostructures with unique properties is useful for the fabrication of quantum confined nanomaterials that are otherwise difficult to produce by direct synthesis. Given that the OA of 1D nanocrystals such as nanorods generally produces linear chains, rod-couple structures, or clustered columns, linking them in a facet-specific manner to produce 2D structures is challenging. Here, we report that 1D Cu_2-xS nanorods undergo etching on exposure to hexylphosphonic acid under mild heating, which results in an increased curvature and a reduction in surface ligands at those sites. This causes the nanorods to fuse via their basal tip facets into chains and then cojoin through diametrically opposed side facets, resulting in atomically coupled, 2D raftlike structures. The stepwise OA of 1D nanocrystals into 2D nanostructures illustrated here expands the range of nanoarchitectures that can be produced via solution-processed methods.

Fluorescent Semiconductor Nanorods for the Solid-Phase Polymerase Chain Reaction-Based, Multiplexed Gene Detection of Mycobacterium tuberculosis

The spread of infectious diseases with significantly high mortality rates can wreak devastating damage on global health systems and economies, underscoring the need for better disease diagnostic platforms. Solid-phase polymerase chain reaction (SP-PCR) potentially combines the advantages of conventional PCR-based diagnostics with the capability of multiplexed detection, given that the spatial separation between primers circumvents unwanted primer-primer interactions. However, the generally low efficiency of solid-phase amplification results in poor sensitivity and limits its use in detection schemes. We present an SP-PCR-based, multiplexed pulldown fluorescence assay for the detection of Mycobacterium tuberculosis (MTB), utilizing highly fluorescent oligonucleotide-functionalized CdSe/CdS and CdSe_1-xS_x/CdS nanorods (NRs) as multicolor hybridization probes. The large surface area of the NRs allows for their easy capture and pulldown, but without contributing significantly to the interparticle photon reabsorption when clustered at the pulldown sites. The NR nanoprobes were specifically designed to target the hotspot regions of the rpoB gene of MTB, which have been implicated in resistance to standard rifampicin treatment. The implementation of the semiconductor NRs as photostable multicolor fluorophores in a multiplexed SP-PCR-based detection scheme allowed for the identification of multiple hotspot regions with sub-picomolar levels of sensitivity and high specificity in artificial sputum. While this work demonstrates the utility of semiconductor NRs as highly fluorescent chromophores that can enable SP-PCR as a sensitive and accurate technique for multipathogen diagnostics, the flexible surface chemistry of the NRs should allow them to be applicable to a wide variety of detection motifs.

Oral Microbiota Transplant in Dogs with Naturally Occurring Periodontitis

In periodontitis patients, dysbiosis of the oral microbiota is not only found at clinically diseased periodontal sites but also at clinically healthy periodontal sites, buccal mucosae, tongue, and saliva. The present study evaluated the safety and efficacy of an oral microbiota transplant (OMT) for the treatment of periodontitis in dogs. Eighteen systemically healthy beagle dogs with naturally occurring periodontitis were enrolled in the study and randomly assigned to a test or control group. A 4-y-old, periodontally healthy female beagle dog served as a universal OMT donor. To reduce periodontal inflammation, all dogs received full-mouth mechanical debridement of teeth and mucosae 2 wk before baseline. At baseline, full-mouth mechanical debridement was repeated and followed by adjunctive subgingival and oral irrigation with 0.1% NaOCl. Subsequently, test dogs were inoculated with an OMT from the healthy donor. No daily oral hygiene was performed after OMT transplantation. Adverse events were assessed throughout the observation period. Clinical examinations were performed and whole-mouth oral microbiota samples were collected at week 2, baseline, week 2, and week 12. The composition of oral microbiota samples was analyzed using high-throughput 16S ribosomal RNA gene amplicon sequencing followed by taxonomic assignment and downstream bioinformatic and statistical analyses. Results demonstrated that the intergroup difference in the primary outcome measure, probing pocket depth at week 12, was statistically insignificant. However, the single adjunctive OMT had an additional effect on the oral microbiota composition compared to the full-mouth mechanical and antimicrobial debridement alone. The OMT resulted in an "ecological shift" toward the composition of the donor microbiota, but this was transient in nature and was not observed at week 12. No local or systemic adverse events were observed throughout the study period. The results indicate that OMT may modulate the microbiota composition in dogs with naturally occurring periodontitis and can be applied safely.

Canadian Rhinology Working Group consensus statement: biologic therapies for chronic rhinosinusitis

BACKGROUND

Recent evidence suggests that biologic therapy with targeted activity within the Type 2 inflammatory pathway can improve the clinical signs and symptoms of chronic rhinosinusitis with nasal polyposis (CRSwNP). There remains a population in CRSwNP that despite medical therapy and endoscopic sinus surgery have persistent signs and symptoms of disease. Therefore, biologics, monoclonal antibody agents, could be beneficial therapeutic treatments for these patients. There have been eight randomized, double-blind, placebo-controlled trails performed for CRSwNP targeted components of the Type 2 inflammatory pathway, notably interleukin (IL)-4, IL-5 and IL-13, IL-5R, IL-33, and immunoglobulin (Ig)E. However, there are no formal recommendations for the optimal use of biologics in managing Chronic Rhinosinusitis (CRS) within the Canadian health care environment.

METHODS

A Delphi Method process was utilized involving three rounds of questionnaires in which the first two were completed individually online and the third was discussed on a virtual platform with all the panelists. 17 fellowship trained rhinologists across Canada evaluated the 28 original statements on a scale of 1-10 and provided comments. A rating within 1-3 indicated disagreement, 8-10 demonstrated agreement and 4-7 represented being neutral towards a statement. All ratings were quantitively reviewed by mean, median, mode, range and standard deviation. Consensus was defined by removing the highest and lowest of the scores and using the "3 point relaxed system".

RESULTS

After three rounds, a total of 11 statements achieved consensus. This white paper only contains the final agreed upon statements and clear rationale and support for the statements regarding the use of biologics in patients with CRS.

CONCLUSION

This white paper provides guidance to Canadian physicians on the use of biologic therapy for the management of patients with CRS, but the medical and surgical regimen should ultimately be individualized to the patient. As more biologics become available and additional trials are published we will provide updated versions of this white paper every few years.

CSO (Canadian Society of Otolaryngology - Head & Neck Surgery) position paper on return to Otolaryngology - Head & Neck Surgery Clinic Practice during the COVID-19 pandemic in Canada

The novel Coronavirus (COVID-19) has created a worldwide deadly pandemic that has become a major public health challenge. All semi-urgent and elective medical care has come to a halt to conserve capacity to care for patients during this pandemic. As the numbers of COVID-19 cases decrease across Canada, our healthcare system also began to reopen various facilities and medical offices. The aim for this document is to compile the current evidence and provide expert consensus on the safe return to clinic practice in Otolaryngology - Head & Neck Surgery. These recommendations will also summarize general precaution principles and practical tips for office across Canada to optimize patient and provider safety. Risk assessment and patient selection are crucial to minimizing exposure to COVID-19. Controversial topics such as COVID-19 mode of transmission, duration of exposure, personal protective equipment, and aerosol-generating procedures will be analyzed and discussed. Practical solutions of pre-visit office preparation, front office and examination room set-up, and check out procedures are explored. Specific considerations for audiology, pediatric population, and high risk AGMPs are also addressed. Given that the literature surrounding COVID-19 is rapidly evolving, these guidelines will serve to start our specialty back into practice over the next weeks to months and they may change as we learn more about this disease.

Branched Heterostructured Semiconductor Nanocrystals with Various Branch Orders via a Facet-to-Facet Linking Process

Branched heterostructured semiconductor nanoparticles such as core seeded tetrapods and octapods offer properties not seen in their spherical core-shell counterparts, but are challenging to synthesize with a large diversity of branch numbers via heterogeneous nucleation and growth processes alone. This work describes a process to facet-link matchstick-like Ag₂S-tipped ZnS nanorods via their Ag₂S tips, producing branched Ag₂S-centered ZnS nanoparticles such as bipods, tripods, and in general multipods with 4 to 16 ZnS arms as a function of reaction time. The angle between nanorods in the bipods and tripods is found to be close to 120°, resulting in unexpected bent and trigonal planar geometry, respectively. This is attributed to the exposed facets of the monoclinic Ag₂S tips, their relative chemical reactivities, and their atomic composition. The formation of particles with an increasing number of branches takes place in a stepwise manner, thus making the facet-linking approach a facile synthesis route to systematically obtaining a diverse set of branched heterostructured semiconductor nanoparticles with a well-defined number of branches.

Adapting re-usable elastomeric respirators to utilise anaesthesia circuit filters using a 3D-printed adaptor - a potential alternative to address N95 shortages during the COVID-19 pandemic

The COVID‐19 pandemic has increased the demand for disposable N95 respirators. Re‐usable elastomeric respirators may provide a suitable alternative. Proprietary elastomeric respirator filters may become depleted as demand increases. An alternative may be the virus/bacterial filters used in anaesthesia circuits, if they can be adequately fitted onto the elastomeric respirators. In addition, many re‐usable elastomeric respirators do not filter exhaled breaths. If used for sterile procedures, this would also require modification. We designed a 3D‐printed adaptor that permits elastomeric respirators to interface with anaesthesia circuit filters and created a simple modification to divert exhaled breaths through the filter. We conducted a feasibility study evaluating the performance of our modified elastomeric respirators. A convenience sample of eight volunteers was recruited. Quantitative fit testing, respiratory rate and end‐tidal carbon dioxide were recorded during fit testing exercises and after 1 h of wear. All eight volunteers obtained excellent quantitative fit testing throughout the trial. The mean (SD) end‐tidal carbon dioxide was 4.5 (0.5) kPa and 4.6 (0.4) kPa at baseline and after 1 h of wear (p = 0.148). The mean (SD) respiratory rate was 17 (4) breaths.min⁻¹ and 17 (3) breaths.min⁻¹ at baseline and after 1 h of wear (p = 0.435). Four out of eight subjects self‐reported discomfort; two reported facial pressure, one reported exhalation resistance and one reported transient dizziness on exertion. Re‐usable elastomeric respirators to utilise anaesthesia circuit filters through a 3D‐printed adaptor may be a potential alternative to disposable N95 respirators during the COVID‐19 pandemic.

P4377Use of LV Deformation Imaging to predict long term Heart Failure Risk in high risk patients

Background

The increasing prevalence of heart failure (HF), due to hypertension, ischaemic heart disease, diabetes, obesity, and ageing population demands identification of at-risk subgroup whom we could target on prevention strategies. In a same cohort of patients at risk of HF (70% with CAD), 13% developed new HF hospitalization or death over 4.3 years of follow-up, however, disease management program did not confer any benefit to outcome and LV ejection fraction (EF) was not predictive of progression to HF. Better risk stratification strategies are needed. In this study, we sought whether advanced echo measure on deformation, global longitudinal strain (GLS) would predict HF admission over a long term follow up and thereby define an at-risk group. Aim: To determine which of the LV morphology, function and deformation parameters, best predict new HF admission or HF death in pts at risk but without prior dx of HF.

Method

Echocardiograms (including measurement of LV, size, function, morphology and deformation) were obtained in 431 inpatients (mean age 65±11, 72% male) at risk of HF. LV global longitudinal strain (GLS) and strain rate (GLSR) were measured offline (EchoPac, GE). Long term (9 years) follow up data were obtained via data linkage.

Results

63 pts (15%) reached the end-point of HF admission or HF death. LV deformation showed a univariable association with outcome (Table). In multivariable analysis, including known significant predictors of outcome (age, sex, BMI, diabetes, hypertension), GLS less than 18 remained an independent predictor (Table), in addition to age and DM at baseline. EF and LV mass were not predictors of heart failure.

HR (95% CI) P value HR (95% CI) P value HR (95% CI) P value Age 1.1 (1–1.1) <0.01 1.1 (1–1.1) 0.04 1 (1–1.1) 0.04 Sex 1.0 (0.6–1.7) 0.9 0.8 (0.4–1.8) 0.6 0.8 (0.4–1.8) 0.6 BMI 1.0 (1–1.1) 0.05 1 (0.9–1.1) 0.7 1 (0.9–1.1) 0.7 DM 2.6 (1.6–4.3) <0.01 2.7 (1.4–5.3) <0.01 2.7 (1.4–5.2) 0.04 LVMI 1.0 (1.0–1.0) <0.01 1 (0.9–1.0) 0.7 1 (0.99–1.0) 0.7 Impaired EF, % 1.0 (0.9–1.0) <0.01 1 (0.9–1.0) 0.16 0.97 (0.94–1.0) 0.04 Diastolic dysfunction 2.3 (1.4–3.7) <0.01 0.8 (0.3–1.7) 0.5 0.7 (0.3–1.7) 0.5 GLS 1.3 (1.4–1.2) <0.01 1.1 (1–1.2) 0.07 GLS <18 5.3 (2.8–10.2) <0.01 2.3 (1.1–5.1) 0.04

Conclusion

GLS <18 is independently associated with increasing new onset heart failure admission and HF mortality in patients at risk of HF.

Associations between Gastro-oesophageal Reflux Disease, Generalised Anxiety Disorder, Major Depressive Episodes, and Healthcare Utilisation: a Community-based Study

OBJECTIVE

To examine the prevalence and comorbidity of gastro-oesophageal reflux disease (GORD) with generalised anxiety disorder (GAD) and major depressive episodes (MDE) in a general population using DSM-IV, and to evaluate the associations between these conditions and healthcare utilisation.

METHODS

A random population-based telephone survey was conducted to record frequency of GORD symptoms, symptoms of GAD and MDE based on DSM-IV, and healthcare utilisation.

RESULTS

Of 2011 respondents, 4.2% had weekly GORD and 13.9% had monthly GORD, whereas 3.8% reported GAD and 12.4% reported MDE. Those with monthly GORD had higher risk of GAD (p = 0.01) and MDE (p < 0.001). GORD symptom frequency was independently correlated with MDE and GAD in a dose-response manner. The number of psychiatric diagnoses was independently correlated with GORD. GORD symptom frequency, GAD, and MDE were correlated with consultation frequency. GORD symptom frequency was corelated with high investigation expenditure.

CONCLUSION

GORD had a strong dose-response relationship with GAD and MDE in a Hong Kong population. Excessive healthcare utilisation should alert clinicians to the risk of psychiatric comorbidity.

Thermochromism from Ultrathin Colloidal Sb2 Se3 Nanowires Undergoing Reversible Growth and Dissolution in an Amine-Thiol Mixture

Liquid-based thermochromics can be incorporated into an arbitrarily shaped container and provide a visual map of the temperature changes within its volume. However, photochemical degradation, narrow temperature range of operation, and the need for stringent encapsulation processes are challenges that can limit their widespread use. Here, a unique solution-based thermochromic comprising ultrathin colloidal Sb₂ Se₃ nanowires in an amine-thiol mixture is introduced. The nanowires undergo reversible growth and dissolution with repeated cycles of heating and cooling between 20 and 160 °C, exhibiting intense and contrasting color changes during these processes. Furthermore, the transition temperature in which a change in color first appears can be continuously tuned over a range larger than 100 °C by introducing controlled amounts of Sn²⁺ . The colloidal nanowire dispersion in the amine-thiol mixture retains its thermochromic properties over hundreds of temperature cycles, continuous heating at 80 °C over months, and shelf life of up to 2 years in an open container under ambient conditions. To illustrate its utility as a robust liquid thermochromic, the nanowire solution is coated onto standard filter paper and its uses as a rewritable surface by thermal scribing, as well as an inexpensive means of visualizing the temperature distribution of an anisotropically heated block are demonstrated.

Multi-color lasing in chemically open droplet cavities

In this paper, we demonstrate FRET-based multicolor lasing within chemically open droplet cavities that allow online modulation of the gain medium composition. To do this, we generated monodisperse microfluidic droplets loaded with coumarin 102 (donor), where the spherical droplets acted as whispering gallery mode (WGM) optical cavities in which coumarin 102 lasing (~ 470 nm) was observed. The lasing color was switched from blue to orange by the introduction of a second dye (acceptor, rhodamine 6 G) into the flowing droplet cavities; subsequent lasing from rhodamine 6 G (~ 590 nm) was observed together with the complete absence of coumarin 102 emission. The ability to control color switching online within the same droplet cavity enables sequential detection of multiple target molecules within or around the cavity. As a demonstration of this concept, we show how the presence of FITC-Dextran and methylene blue (MB) in the medium surrounding the lasing droplets can be sequentially detected by the blue and orange laser respectively. The method is simple and can be extended to a range of water-soluble dyes, thus enabling a wide spectral range for the lasing with the use of a single pump laser source.

Stable, Ultralow Threshold Amplified Spontaneous Emission from CsPbBr3 Nanoparticles Exhibiting Trion Gain

Wet-chemically synthesized cesium lead halide nanoparticles have many attractive properties that make them promising as optical gain media, but generally suffer from poor stability under ambient conditions and an optical gain threshold that is widely believed to be dictated by the need for biexcitons. These conditions make it impractical for such particles to be utilized as gain media given the need to undergo repeated stimulated emission processes at above-threshold pump intensities over long periods of time. We demonstrate that the surface treatment of CsPbBr₃ nanoparticles with a mixture of PbBr₂, oleic acid, and oleylamine not only raises their fluorescence quantum yield to nearly unity and prolongs their stability in air from days to months, but it also dramatically increases their trion photoluminescence lifetime from ∼0.9 to ∼1.6 ns. Via a combination of time-resolved photoluminescence and transient absorption spectroscopy, we provide evidence for trion gain at sufficiently low pump intensities in which the likelihood of predominantly biexciton-based gain is small. We then show that, in line with theoretical prediction, the amplified spontaneous emission (ASE) threshold of a thin film of surface-treated CsPbBr₃ nanoparticles reduces to a record low of ∼1.2 μJ/cm² with a corresponding average exciton occupancy per nanoparticle of 0.62. The ultralow pump threshold and increased stability allow for stable ASE over millions of laser shots, paving the way for the deployment of these nanoparticles as viable solution-processed optical gain media.

Stable, Ultralow Threshold Amplified Spontaneous Emission from CsPbBr3 Nanoparticles Exhibiting Trion Gain

Wet-chemically synthesized cesium lead halide nanoparticles have many attractive properties that make them promising as optical gain media, but generally suffer from poor stability under ambient conditions and an optical gain threshold that is widely believed to be dictated by the need for biexcitons. These conditions make it impractical for such particles to be utilized as gain media given the need to undergo repeated stimulated emission processes at above-threshold pump intensities over long periods of time. We demonstrate that the surface treatment of CsPbBr₃ nanoparticles with a mixture of PbBr₂, oleic acid, and oleylamine not only raises their fluorescence quantum yield to nearly unity and prolongs their stability in air from days to months, but it also dramatically increases their trion photoluminescence lifetime from ∼0.9 to ∼1.6 ns. Via a combination of time-resolved photoluminescence and transient absorption spectroscopy, we provide evidence for trion gain at sufficiently low pump intensities in which the likelihood of predominantly biexciton-based gain is small. We then show that, in line with theoretical prediction, the amplified spontaneous emission (ASE) threshold of a thin film of surface-treated CsPbBr₃ nanoparticles reduces to a record low of ∼1.2 μJ/cm² with a corresponding average exciton occupancy per nanoparticle of 0.62. The ultralow pump threshold and increased stability allow for stable ASE over millions of laser shots, paving the way for the deployment of these nanoparticles as viable solution-processed optical gain media.

Up-regulation of transient receptor potential vanilloid (TRPV) and down-regulation of brain-derived neurotrophic factor (BDNF) expression in patients with functional dyspepsia (FD)

BACKGROUND

The role of immune activation in Functional Dyspepsia (FD) patients without previous infection is unclear. We compare the gastric and circulating brain-derived neurotropic factor (BDNF), receptor potential vanilloid type (TRPV) families and various cytokines in FD patients.

METHODS

Consecutive adult FD patients (Rome III) with no recent history of gastroenteritis and asymptomatic healthy controls were recruited for upper endoscopy. Subjects with GERD and IBS as predominant symptoms, diabetes mellitus, current or previous Helicobacter pylori infection, psychiatric illness and recent use of NSAID or PPI were excluded. Corpus biopsies and serum samples were collected.

KEY RESULTS

Forty three [M:F=8:35, mean age: 35.0 (9.3)] FD patients were compared with 23 healthy controls [M:F=8:15, mean age: 36.6 (10.2)]. FD patients had postprandial distress syndrome (PDS) as predominant sub-type (PDS: 36, EPS: 2). There was no significant difference in the median inflammation score (FD:0 (0-1) vs Control:0 (0-1), P=.79). However, FD patients had significantly higher mRNA expression of TRPV1 (FD:0.014±0.007, Control:0.003±0.001, 4.6 fold, P=.02) and TRPV2 (FD:0.012±0.006, Control:0.003±0.001, 4 fold, P=.02) compared to controls. The serum (FD:258.0±12.3 ng ml^-1 , Control:319.7±18.1 ng ml^-1 , P<.01) and gastric BDNF mRNA (FD:0.06±0.008, Control:0.092±0.01, 0.65 fold, P=.02)levels significantly lower in FD patients. Secretion of cytokines (IL-4, IL-5, IL-6, IL-8, IL-10, G-CSF, TGF-β2, MCP-1)was also highly correlated with dyspeptic symptoms in patients with FD.

CONCLUSIONS & INFERENCES

Despite lacking gastric mucosal inflammation, up-regulation of TRPV1 and TRPV2, down-regulation of BDNF were observed in FD patients. These suggest that immune alteration may contribute to the pathogenesis of FD without any previous infection.

Highly fluorescent, monolithic semiconductor nanorod clusters for ultrasensitive biodetection

Signal amplified, ultrasensitive fluorescence detection of the tetanus toxoidviahighly fluorescent, monolithic semiconductor nanorod clusters.

Embedding liquid lasers within or around aqueous microfluidic droplets

In this paper, we demonstrate the incorporation of dye-based liquid lasers within or around flowing aqueous microfluidic droplets. In particular, we use dye solutions in benzyl alcohol, and either disperse an ensemble of small (∼20 μm) lasing droplets within large (∼500 μm) aqueous droplets flowing in a simple glass capillary-based microfluidic device, or 'wrap' a thin (∼10 μm) lasing benzyl alcohol shell around larger (∼560 μm) microfluidic aqueous droplets. We experimentally and theoretically characterize the lasing behavior in both cases, which is supported by whispering-gallery mode (WGM) optical resonances at the droplet interfaces. We showcase a simple application of our method, which highlights the advantages of having embedded, spatially segregated laser sources within a droplet containing a model analyte solution. With this method, each microfluidic droplet now functions not only as an isolated experiment flask, but is also capable of on drop sensing that exploits WGM-based lasing, thus expanding the possibilities for online monitoring of biophysical/biochemical processes and sensitive detection of biomolecules in droplet-based microfluidics.

Bronchopulmonary dysplasia-associated pulmonary hypertension: clues from placental pathology

OBJECTIVES

Bronchopulmonary dysplasia (BPD) and the associated complication of pulmonary hypertension (PH) leads to increased mortality and a longer length of stay among survivors. Placental histopathology may give early clues of subsequent events. The objective was to evaluate the relationship of maternal vascular underperfusion (MVU) changes on placental histopathology with subsequent development of BPD-associated PH in a cohort of extremely premature infants.

STUDY DESIGN

In a cohort of preterm infants '⩽28 weeks' gestational age (GA) and with 'severe' BPD, this retrospective study evaluated specific placental histopathological changes and assessed the relationship with subsequent development of PH. 'Severe' BPD was defined as the need for ⩾30% oxygen and/or positive pressure ventilation at 36 weeks postmenstrual age. Placental and echocardiographic assessments were done by investigators masked to the grouping and clinical outcomes.

RESULTS

Fifty six infants with severe BPD formed the cohort; PH was noted in 22 (39.3%) infants. The GA of the infants with and without PH was comparable (25.8±1.6 vs 25.8±1.3 weeks, P=0.9). On placental histopathological examination, 13 (23%) had features of MVU. On univariate logistic regression, the presence of changes consistent with MVU increased the relative risk of subsequent BPD-associated PH by 2.75 (95% confidence interval 1.56 to 4.85, P=0.004). The significance persisted after adjustment for GA. Stratification by the presence or absence of fetal growth restriction, yielded nonsignificant associations (P=0.17).

CONCLUSION

Based on the results of the present study, specific placental histopathological changes may give early clues to the subsequent development of BPD-associated PH.

Facet-to-facet Linking of Shape-anisotropic Colloidal Cadmium Chalcogenide Nanostructures

Here, we describe a protocol that allows for shape-anisotropic cadmium chalcogenide nanocrystals (NCs), such as nanorods (NRs) and tetrapods (TPs), to be covalently and site-specifically linked via their end facets, resulting in polymer-like linear or branched chains. The linking procedure begins with a cation-exchange process in which the end facets of the cadmium chalcogenide NCs are first converted to silver chalcogenide. This is followed by the selective removal of ligands at their surface. This results in cadmium chalcogenide NCs with highly reactive silver chalcogenide end facets that spontaneously fuse upon contact with each other, thereby establishing an interparticle facet-to-facet attachment. Through the judicious choice of precursor concentrations, an extensive network of linked NCs can be produced. Structural characterization of the linked NCs is carried out via low- and high-resolution transmission electron microscopy (TEM), as well as energy-dispersive X-ray spectroscopy, which confirm the presence of silver chalcogenide domains between chains of cadmium chalcogenide NCs.

Oral treponeme major surface protein: Sequence diversity and distributions within periodontal niches

Treponema denticola and other species (phylotypes) of oral spirochetes are widely considered to play important etiological roles in periodontitis and other oral infections. The major surface protein (Msp) of T. denticola is directly implicated in several pathological mechanisms. Here, we have analyzed msp sequence diversity across 68 strains of oral phylogroup 1 and 2 treponemes; including reference strains of T. denticola, Treponema putidum, Treponema medium, 'Treponema vincentii', and 'Treponema sinensis'. All encoded Msp proteins contained highly conserved, taxon-specific signal peptides, and shared a predicted 'three-domain' structure. A clone-based strategy employing 'msp-specific' polymerase chain reaction primers was used to analyze msp gene sequence diversity present in subgingival plaque samples collected from a group of individuals with chronic periodontitis (n=10), vs periodontitis-free controls (n=10). We obtained 626 clinical msp gene sequences, which were assigned to 21 distinct 'clinical msp genotypes' (95% sequence identity cut-off). The most frequently detected clinical msp genotype corresponded to T. denticola ATCC 35405^T , but this was not correlated to disease status. UniFrac and libshuff analysis revealed that individuals with periodontitis and periodontitis-free controls harbored significantly different communities of treponeme clinical msp genotypes (P<.001). Patients with periodontitis had higher levels of clinical msp genotype diversity than periodontitis-free controls (Mann-Whitney U-test, P<.05). The relative proportions of 'T. vincentii' clinical msp genotypes were significantly higher in the control group than in the periodontitis group (P=.018). In conclusion, our data clearly show that both healthy and diseased individuals commonly harbor a wide diversity of Treponema clinical msp genotypes within their subgingival niches.

Salivary microbiome of an urban Indian cohort and patterns linked to subclinical inflammation

OBJECTIVE

To profile salivary microbiomes of an urban-living, healthy Indian cohort and explore associations with proinflammatory status.

METHODS

Fifty-one clinically healthy Indian subjects' salivary microbiomes were analyzed using 16S rRNA Illumina MiSeq sequencing. Community distribution was compared with salivary data from the Human Microbiome Project (HMP). Indian subjects were clustered using microbiome-based "partitioning along medoids" (PAM), and relationships of interleukin-1 beta levels with community composition were analyzed.

RESULTS

Indian subjects presented higher phylogenetic diversity than HMP. Several taxa associated with traditional societies gut microbiomes (Bacteroidales, Paraprevotellaceae, and Spirochaetaceae) were raised. Bifidobacteriaceae and Lactobacillaceae were approximately fourfold greater. A PAM cluster enriched in several Proteobacteria, Actinobacteria, and Bacilli taxa and having almost twofold higher Prevotella to Bacteroides ratio showed significant overrepresentation of subjects within the highest quartile of salivary interleukin-1 beta levels. Abiotrophia, Anaerobacillus, Micrococcus, Aggregatibacter, Halomonas, Propionivivrio, Paracoccus, Mannhemia, unclassified Bradyrhizobiaceae, and Caulobacteraceae were each significant indicators of presence in the highest interleukin-1 beta quartile. 2 OTUs representing Lactobacillus fermentum and Cardiobacterium hominis significantly correlated with interleukin-1 beta levels.

CONCLUSION

The salivary microbiome of this urban-dwelling Indian cohort differed significantly from that of a well-studied Western cohort. Specific community patterns were putatively associated with subclinical inflammation levels.

Pump-Power Dependence of Coherent Acoustic Phonon Frequencies in Colloidal CdSe/CdS Core/Shell Nanoplatelets

Femtosecond optical pump-probe spectroscopy resolves hitherto unobserved coherent acoustic phonons in colloidal CdSe/CdS core/shell nanoplatelets (NPLs). With increasing pump fluence, the frequency of the in-plane acoustic mode increases from 5.2 to 10.7 cm^-1, whereas the frequency of the out-of-plane mode remains at ∼20 cm^-1. Analysis of the oscillation phases suggests that the coherent acoustic phonon generation mechanism transitions from displacive excitation to subpicosecond Auger hole trapping with increasing pump fluence. The measurements yield Huang-Rhys parameters of ∼10^-2 for both acoustic modes. The weak electron-phonon coupling strengths favor the application of NPLs in optoelectronics.

Sub-Picosecond Auger-Mediated Hole-Trapping Dynamics in Colloidal CdSe/CdS Core/Shell Nanoplatelets

Quasi-two-dimensional colloidal nanoplatelets (NPLs) have recently emerged as a class of semiconductor nanomaterials whose atomically precise monodisperse thicknesses give rise to narrow absorption and emission spectra. However, the sub-picosecond carrier dynamics of NPLs at the band edge remain largely unknown, despite their importance in determining the optoelectronic properties of these materials. Here, we use a combination of femtosecond transient absorption spectroscopy and nonadiabatic molecular dynamics simulations to investigate the early time carrier dynamics of CdSe/CdS core/shell NPLs. Band-selective probing reveals sub-picosecond Auger-mediated trapping of holes with an effective second-order rate constant of 3.5 ± 1.0 cm²/s. Concomitant spectral blue shifts that are indicative of Auger hole heating are found to occur on the same time scale as the sub-picosecond trapping dynamics, whereas spectral red shifts that emerge at low excitation densities furnish an electron-cooling time scale of 0.84 ± 0.09 ps. Finally, nonadiabatic molecular dynamics simulations relate the observed sub-picosecond Auger-mediated hole-trapping dynamics to a shallow trap state that originates from the incomplete passivation of dangling bonds on the NPL surface.