Single Recordings Research Articles

Impact of shock index (SI), modified SI, and age-derivative indices on acute heart failure prognosis; A systematic review and meta-analysis

Background Heart failure (HF) is still associated with quite considerable mortality rates and usage of simple tools for prognosis is pivotal. We aimed to evaluate the effect of shock index (SI) and its derivatives (age SI (ASI), modified SI (MSI), and age MSI (AMSI)) on acute HF (AHF) clinical outcomes. Methods PubMed/Medline, Scopus and Web of science databases were screened with no time and language limitations till February 2024. We recruited relevant records assessed SI, ASI, MSI or AMSI with AHF clinical outcomes. Results Eight records were selected (age: 69.44±15.05 years). Mean SI in those records reported mortality (either in-hospital or long-term death) was 0.67 (95% confidence interval (CI):0.63–0.72)). In-hospital and follow-up mortality rates in seven(n = 12955) and three(n = 5253) enrolled records were 6.18% and 10.14% with mean SI of 0.68(95%CI:0.63–0.73) and 0.72(95%CI:0.62–0.81), respectively. Deceased versus survived patients had higher SI difference (0.30, 95%CI:0.06–0.53, P = 0.012). Increased SI was associated with higher chances of in-hospital death (odds ratio (OR): 1.93, 95%CI:1.30–2.85, P = 0.001).The optimal SI cut-off point was found to be 0.79 (sensitivity: 57.6%, specificity: 62.1%). In-hospital mortality based on ASI was 6.12% (mean ASI: 47.49, 95%CI: 44.73–50.25) and significant difference was found between death and alive subgroups (0.48, 95%CI:0.39–0.57, P<0.001). Also, ASI was found to be independent in-hospital mortality predictor (OR: 2.54, 95%CI:2.04–3.16, P<0.001)). The optimal ASI cut-off point was found to be 49.6 (sensitivity: 66.3%, specificity: 58.6%). In terms of MSI (mean: 0.93, 95%CI:0.88–0.98)), significant difference was found specified by death/survival status (0.34, 95%CI:0.05–0.63, P = 0.021). AMSI data synthesis was not possible due to presence of a single record. Conclusions SI, ASI, and MSI are practical available tools for AHF prognosis assessment in clinical settings to prioritize high risk patients.

Eurasian spruce bark beetle detects lanierone using a highly expressed specialist odorant receptor, present in several functional sensillum types

BackgroundInsects detect odours using odorant receptors (ORs) expressed in olfactory sensory neurons (OSNs) in the antennae. Ecologically important odours are often detected by selective and abundant OSNs; hence, ORs with high antennal expression. However, little is known about the function of highly expressed ORs in beetles, since few ORs have been functionally characterized. Here, we functionally characterized the most highly expressed OR (ItypOR36) in the bark beetle Ips typographus L. (Coleoptera, Curculionidae, Scolytinae), a major pest of spruce. We hypothesized that this OR would detect a compound important to beetle fitness, such as a pheromone component. We next investigated the antennal distribution of this OR using single sensillum recordings (SSR) and in situ hybridization, followed by field- and laboratory experiments to evaluate the behavioural effects of the discovered ligand.ResultsWe expressed ItypOR36 in HEK293 cells and challenged it with 64 ecologically relevant odours. The OR responded exclusively to the monoterpene-derived ketone lanierone with high sensitivity. Lanierone is used in chemical communication in North American Ips species, but it has never been shown to be produced by I. typographus, nor has it been studied in relation to this species’ sensory physiology. Single sensillum recordings revealed a novel and abundant lanierone-responsive OSN class with the same specific response as ItypOR36. Strikingly, these OSNs were co-localized in sensilla together with seven different previously described OSN classes. Field experiments revealed that low release rates of lanierone inhibited beetle attraction to traps baited with aggregation pheromone, with strongest effects on males. Female beetles were attracted to lanierone in laboratory walking bioassays.ConclusionsOur study highlights the importance of the so-called ‘reverse chemical ecology’ approach to identify novel semiochemicals for ecologically important insect species. Our discovery of the co-localization pattern involving the lanierone OSN class suggests organizational differences in the peripheral olfactory sense between insect orders. Our behavioural experiments show that lanierone elicits different responses in the two sexes, which also depend on whether beetles are walking in the laboratory or flying in the field. Unravelling the source of lanierone in the natural environment of I. typographus is required to understand these context-dependent behaviours.

Bioacoustic and Ecoacoustic Data in Audiovisual Core

Audiovisual Core (Audiovisual Core Maintenance Group 2023), is the TDWG standard for metadata related to biodiversity multimedia. The Audiovisual Core Maintenance Group has been working to expand the standard to provide the terms necessary for handling sound recordings. Audiovisual Core can now handle acoustic metadata related to biodiversity from single species (bioacoustics) to the ecosystem scale (ecoacoustics). Bioacoustics The Natural History Museum, London has a significant collection of recorded insect sounds (Ragge and Reynolds 1998) that are often directly linked to museum specimens (Fig. 1). The sound collection has previously been digitised and made available electronically through the BioAcoustica project (Baker et al. 2015). The BioAcoustica platform allows for annotation of audio files with tags including "Call" for deliberate sound made by an organism, "Voice Introduction" for metadata, and "Extraneous Noise." These boundaries are defined by their start and end times (in seconds) relative to the start of the file (Fig. 2). Ecoacoustics Ecoacoustics deals with the sounds present within an entire soundscape or ecosystem. The calls of individual species form the biological part of the soundscape (biophony) alongside sounds produced by non-living natural sources (geophony) and humans (anthropophony). Individual components are often defined by date and time boundaries, and sometimes by upper and lower frequency limits (Fig. 3). Regions of Interest The recently added concept of a "Region of Interest" (ROI) allows for the annotation of sound files, identifying multiple regions within a single recording with time and/or frequency bounds. However, the vocabulary of ROI*1 is not just intended for sounds. Equivalent terms also allow for regions to be specified with images and videos. The use of well-defined annotations has the potential to generate large amounts of training data for machine learning models and provide a standard for generating observation records from these models (e.g., BirdNet, see Kahl et al. 2021), which can be verified by linking them to audio segments within a much larger recording. The development of a metadata standard for regions of interest has several interesting possibilities, including linking multiple observation records to a single soundscape recording (the recording acts similarly to a voucher specimen) and aggregating regions across multiple datasets to create larger corpora for training machine learning models.

Abstract 4114276: Identification of the heterogeneity in the risk of heart failure in those with left bundle branch block pattern using artificial intelligence

Introduction: The association between left bundle branch block (LBBB) and heart failure is well-established. However, the lack of a practical risk assessment tool for patients with LBBB poses a clinical challenge to the management despite the heterogeneity of the LBBB population. Hypothesis: Artificial intelligence (AI) can extract features to stratify the risk of heart failure (HF) within the heterogeneity of LBBB. Methods: All 12-lead ECGs diagnosed with LBBB recorded from 1/1/2015 to 12/31/2019 were identified in our institution. ECG data were analyzed as 2D matrices with a shape of 12×2500. The Uniform Manifold Approximation and Projection (UMAP) was used to visualize the heterogeneity of LBBB ECG. Additionally, a 2-dimensional convolutional neural network model was trained to detect LBBB ECGs associated with past HF diagnosis. The model was then applied to ECGs from an external cohort of patients with LBBB but without a history of HF. Cumulative incidences of HF admission were compared by stratifying according to tertiles of the model output (low, intermediate and high AI score groups) Results: We identified 15,124 LBBB ECGs in our institution (training dataset) and 2,463 individuals with LBBB ECGs in the external cohort (external test dataset). The UMAP projection of the ECGs revealed distinct heterogeneity in the data ( Fig A ). This heterogeneity was not fully explained by patient demographics, ECG features, or institutions. When the external cohort was divided into 3 groups according to the tertile of AI prediction, patients with high AI scores had a higher risk of HF admission (high vs low AI score group: hazard ratio (HR), 2.10; 95% confidence interval (CI), 1.66-2.65; intermediate vs low AI score group: HR, 1.39; 95%CI, 1.08-1.78: log-rank p <0.0001; Fig 1B ). This finding was unchanged after adjusting for multiple clinical characteristics and ECG parameters, including QRS duration. Conclusion: We observed significant heterogeneity in ECGs presenting LBBB, and the AI model excellently stratified the risk of heart failure admission in patients with LBBB from a single recording of 12-lead ECG, suggesting great potential for clinical utility in managing patients with LBBB.

Cardiovascular health in women with turner's syndrome: a 3-year single centre audit

Abstract Background Turner’s syndrome (TS) is the most common genetic abnormality affecting females and is characterised by complete or partial absence of the X chromosome. Mortality is predominantly related to cardiovascular disease (1). Risk of life-threatening aortic dissection is 40 per 100,000 (2). Indexed aorta size (ASI) to body surface area (BSA) >20mm/m² is considered abnormal. An ASI of ≥25mm/m² is associated with increased risk of aortic dissection (3). Despite this there is a paucity of data in the literature regarding TS cardiovascular disease and providing evidence-based care can be challenging. Purpose Define cardiovascular disease, with focus upon aortopathy in our TS Cardiovascular Clinic (TCC). Methods Single centre retrospective medical record analysis of 248 women with TS (2021-2024) Results Patient baseline characteristics; mean age 37 years (range 18-75yrs), height 150cm (132-169cm), weight 62kg (37-130kg), BSA 1.55m² (1.19-2.17m²). 65 patients (29%) had bicuspid aortic valve (BAV), 19 (8%) and 5 (3%) had repaired and un-repaired aortic coarctation (CoA) respectively. 30 (13%) had other congenital heart disease, with most common was partial anomalous pulmonary venous connection (12 patients: 5%). 22/248 patients had previous aortic root surgery; 20 elective (mean ASI 29mm/m², range 26-33mm/m², mean age at time of surgery 42 years); 2 presented with aortic dissection (ASI 21mm/m²; pregnant, BAV & 24mm/m²; tri-leaflet aortic valve, TAV). Data was available for 221 unoperated patients (figure 1). The site of maximal dimension was observed at the sinus of Valsalva in 70% compared to 30% at the ascending aorta. 130 patients (59%) had maximal ASI of <20mm/m². Dimensions of 20-23mm/m² and 23-25mm/m² were seen in 64 (29%) and 18 (8%) patients respectively. 7 patients (3%) had a maximal ASI of >25mm/m². 4 patients (2%) had an absolute maximal dimension of 40mm with ASI of 23mm/m² for all four. 9/11 patients with dimension ≥25mm/m² or 40mm had a body mass index (BMI) >25kg/m². Review of medical history for patients at and above threshold for risk of aortic dissection revealed referral to or previous discussion in an Aortic multi-disciplinary meeting (MDT) with a plan for ongoing surveillance. 57 patients (35%) with TAV had significant aortopathy (mean age 46years, range 19-75years) compared with 33 (51%) with BAV (mean age 39yrs, range 22-72 years) (figure 2). Review of patients >55years of age demonstrated a very similar burden of aortopathy in both TAV (14%) and BAV (15%) populations. Conclusions A high burden of cardiovascular disease exists within our TS population. There is a very high prevalence of aortopathy, increasingly with age and both with and without the presence of a bicuspid aortic valve. More published data is needed to help better define those at risk.

The development and testing of a single-arm feasibility and acceptability study of a whole foods diet intervention for adults with prediabetes and their offspring

BackgroundDiet is considered a first-line treatment option for prediabetes, a condition that affects 96 million United States (U.S.) adults. Diet patterns that prioritize whole foods (e.g., Mediterranean) are currently recommended to treat prediabetes. However, no studies have tested whether a U.S.-style diet pattern that prioritizes whole foods can be used to treat prediabetes. The purpose of this study was to assess the feasibility and acceptability of a whole foods diet for adults with prediabetes and their offspring prior to conducting a larger clinical trial.MethodsA 2-week single-arm pre-post experimental controlled-feeding intervention of a 2020–2025 Dietary Guidelines for Americans adapted whole foods diet (e.g., primarily focused on foods that have undergone limited processing or refinement) was conducted in adults (25–59 years) with prediabetes and their biological offspring (6–17 years). Families received 2 weeks of menus and grocery delivery and weekly counseling by a registered dietitian. Families were invited to attend an optional focus group session. Feasibility was based on having a ≥ 50% family completion rate with ≥ 80% completion of study outcomes. Measures included adult–child anthropometrics (weight [kg], body mass index [BMI] including BMI% and Z-scores for offspring, waist circumference [cm]) and child diet quality estimated using the 2015 Healthy Eating Index (HEI) from a single random food record. Wilcoxon signed rank was used to compare differences between baseline and 2-week anthropometrics measures and offspring total HEI scores. Qualitative data were analyzed using thematic analysis to understand factors attributed to diet adherence and acceptability.ResultsEight families enrolled (n = 8 adults, n = 12 offspring), with 7 families completing the study (12% attrition) and completing 100% of study outcome measures. Adults experienced a median weight loss of − 1.0 kg from baseline to 2 weeks (79.5 kg to 78.5 kg). Offspring had a 24-point increase in total 2015 HEI scores (median difference 50 to 74). Focus group participants (n = 4 adults) reported being satisfied with the program and expressed a willingness to continue the diet despite identified barriers.ConclusionsA whole foods diet that provides dietary support was found to be feasible and acceptable for families at risk for T2D. Future studies are needed to test the effects of the diet on prediabetes outcomes, diet quality, and diet adherence in adults and families.Trial registrationNCT05483972 at ClinicalTrials.gov. Registered July 25, 2022. https://clinicaltrials.gov/study/NCT05483972?cond=prediabetes&term=whole%20foods%20&rank=1

Estimating the impact on patient safety of enabling the digital transfer of patients’ prescription information in the English NHS

ObjectivesTo estimate the number and burden of medication errors associated with prescription information transfer within the National Health Service (NHS) in England and the impact of implementing an interoperable prescription...

Visual exposure to green light therapy reduces knee joint pain and alters the lipidome in osteoarthritic rats.

Visual exposure to dim, green, light has been found to reduce pain levels in patients living with migraine, low back pain, and fibromyalgia. Preclinical studies discovered that the analgesic effect of green light was due to the central release of endogenous opioids and a reduction in inflammatory cytokines in the cerebrospinal fluid. The present study assessed the effect of green light therapy (GLT) on joint pain in a rat model of osteoarthritis (OA) and investigated the role of endolipids. Male and female Wistar rats (207-318 g) received an intra-articular injection of sodium monoiodoacetate (3 mg in 50 μL saline) into the knee to induce OA. On day 9, animals were placed in a room illuminated by either white (neutral-white 4000K; 20 lux) or green (wavelength: 525 nm; luminance: 20 lux) light for 5 days (8 hours per day). Joint nociception was assessed by von Frey hair algesiometry, dynamic weight bearing, and in vivo single unit extracellular recordings from knee joint mechanonociceptors. Compared to white light, GLT significantly reduced secondary mechanical hypersensitivity in both sexes and improved hindlimb weight bearing in females only. There was no effect of GLT on joint nociceptor activity in either sex. Serum lipidomics indicated an increase in circulating analgesic endolipids in response to GLT, particularly the N-acyl-glycines. Partial blockade of the endocannabinoid system with the G protein receptor-18/cannabinoid-1 receptor antagonist AM281 (500 μg/kg i.p.) attenuated GLT-induced analgesia. These data show for the first time that GLT acts to reduce OA pain by upregulating circulating analgesic endolipids, which then engage the endocannabinoid system.

Embolization of posterior fossa meningiomas supplied with meningohypophyseal trunk by using n-BCA and dual balloon protection.

Efficacy of tumor embolization for posterior fossa meningioma is controversial due to the lack of adequate embolization for dangerous feeders. Of these, a meningohypophyseal trunk (MHT) has high therapeutic value despite the high risks associated with embolization. To analyze the utility of preoperative MHT embolization for posterior fossa meningiomas using n-BCA with dual balloon protection, a single center retrospective record review was performed on eight consecutive patients who underwent preoperative tumor embolization via the MHT for posterior fossa meningiomas between 2020 and 2024. All patients successfully embolized the MHT using n-BCA. Complete obliteration was achieved in five cases, which is related to the tentorial artery alone as the feeding vessel. None of the patients had cerebral infarction associated with distal embolization. One patient experienced worsening of preoperatively observed abducens nerve palsy due to cranial nerve ischemia. Gross total resection was achieved in seven of eight cases. The mean estimated blood loss during surgical resection was 186 mL (range, 39-392 mL). The mean operative time was 431 min (range, 317-767 min). The MHT embolization of posterior fossa meningiomas by using n-BCA is technically feasible with a high success rate and an acceptable complication rate. MHT=meningohypophyseal trunk; ILT=inferolateral trunk; CPA=Cerebellopontine angle; BGC=balloon guide catheter; PVA=polyvinyl alcohol; GTR=Gross Total Resection; CN=Cranial nerve.

Antennal sensilla of Cyclocephala barrerai (Coleoptera: Melolonthidae): morphology, sexual dimorphism, allometric relationships, and function.

Scarab beetles use pheromones and volatiles to search for their partners and host plants. The perception of these compounds occurs in the beetle antennae, particularly in the sensilla. Relatively few studies have morphologically and physiologically characterized the sensilla of scarab beetles. Cyclocephala barrerai Martínez is a beetle distributed in Mexico. Male beetles have larger antennal lamellae than females, and in both cases, the size of this structure is related to their weight. Previous studies have reported that both sexes are attracted to bacterial volatiles isolated from the female genital chambers. Female cuticular hydrocarbons may act as a sexual contact pheromone. However, antennal sensilla and their electrophysiological responses to behaviorally relevant compounds remain to be investigated. Here, we describe and report the types, allometric relationships, and functions of sensilla found in the lamellae of both C. barrerai sexes. Sensilla were identified, classified, measured, and counted to identify intra and intersexual relationships. The single sensillum recordings showed that plant volatiles, hydrocarbons, and heat stimulated receptor neurons. We identified 2 new types of sensilla basiconica in the scape. Males have more and larger antennal sensilla placodea IV, which specializes in detecting pheromones, plant volatiles, and heat. Females have a greater diversity of sensilla.

Investigating 10 Yr of Volcanoacoustic Activity at Tungurahua Volcano, Ecuador, Aided by Machine Learning

Abstract Here, we present the results of applying diverse data processing and machine learning tools to investigate a very large dataset obtained from single station infrasonic recordings from the last 10 yr of the most recent period of explosive activity at Tungurahua volcano, Ecuador. To increase the quality and quantity of information extracted from the large data set and enhance pattern recognition, we combined traditional techniques with more recent ones. We divided the investigation into sequential steps: detection, discrimination, cleaning, and clustering. For the detection step, we tested the classical short-term average/long-term average algorithm and an algorithm specific for explosions detection called “Volcanic INfrasound Explosions Detector Algorithm (VINEDA)” and detected 118,516 events. To clean the detected signals from potential false positives, we used supervised classification that reduced the events to 75,483, and a catalog cleaning procedure using shallow learners including support vector machines, random forests, and a single layer neural network, trained using data from a manual catalog, to a final number of 36,359 events. This led to a sixfold increase in detected explosions compared to the manual catalog. Then, we applied hierarchical clustering to a well-studied time window of activity using two independent difference metrics: dynamic time warping and waveform cross correlation and showed the insights and drawbacks from this approach. We showed that the different techniques were able to reveal repeating and striving events between selected different eruptive phases and associated them to possible changes in eruptive dynamics. Finally, to analyze the whole dataset at once we used a convolutional autoencoder network and obtained similar results to the classical clustering in a fraction of the time. We identified different families of explosions that appeared, sometimes intermittently, and revealed various potentially competing eruptive processes during the whole time period.

A preserved neural code for temporal order between memory formation and recall in the human medial temporal lobe.

Temporal memory enables us to remember the temporal order of events happening in our life. The human medial temporal lobe (MTL) appears to contain neural representations supporting temporal memory formation, but the cellular mechanisms that preserve temporal order information for recall are largely unknown. Here, we examined whether human MTL neuronal activity represents the temporal position of events during memory formation and recall, using invasive single and multi-unit recordings in human epilepsy patients (n = 19). Participants freely navigated a virtual environment in order to explore and remember locations and temporal positions of objects. During each exploration period, they sequentially encountered two or three different objects, placed in different locations. This allowed us to examine single- and multi-unit neuronal firing rates (FR) as a function of the temporal position the objects were presented in. We found that a significant number of multi-units and single-units in various MTL regions including the hippocampus showed selectivity to the temporal position of objects during the exploration period. During recall, patients were asked to indicate which one of two objects from the same trial was found latter. Neural firing rates during recall showed a selectivity supporting recall of temporal positions. Interestingly, most of the selective single-units that stayed selective during encoding and recall preserved their temporal position preference. Our results thus suggest that neuronal activity in the human MTL contains a preserved neural code for temporal order in memory formation and recall.

Odorant receptors tuned to isothiocyanates in Drosophila melanogaster and their evolutionary expansion in herbivorous relatives.

Plants release complex volatile compounds to attract mutualists, deter herbivores, and deceive pollinators. Here, we used herbivorous specialist flies that feed on mustard plants ( Scaptomyza spp.) and microbe-feeding species ( Drosophila melanogaster and Scaptomyza spp.) to investigate how plant-derived electrophilic toxins such as isothiocyanates (ITCs) affect insects, and how flies detect these compounds through olfaction. In survival assays, D. melanogaster exposed to volatile allyl isothiocyanate (AITC), a toxin derived from many Brassicales plants, were acutely intoxicated, demonstrating the high toxicity of this volatile compound to non-specialized insects. Through single sensillum recordings (SSR) from olfactory organs and behavioral assays, we found that the Odorant receptor 42a (Or42a) is necessary for AITC detection and behavioral aversion. Comparative transcriptome and RNA FISH studies across the drosophilid genus Scaptomyza revealed lineage-specific triplication of Or42a in the Brassicales specialists and a doubling of Or42a -positive-olfactory sensory neurons. Heterologous expression experiments showed that Or42a paralogs in Brassicales-specialists exhibited broadened sensitivity to ITCs in a paralog-specific manner. Finally, AlphaFold2 modeling followed by site-directed mutagenesis and SSR identified two critical amino acid substitutions that conferred Or42a heighten sensitivity to Brassicales-derived ITCs. Our findings suggest that ITCs, which are toxic to most insects, can be detected and avoided by non-specialists like D. melanogaster through olfaction. In Brassicales specialists, these same Ors experienced gene duplication events that resulted in an expanded sensitivity to ITC compounds. Thus, the insect's olfactory system can rapidly adapt to toxic ecological niches provided by chemically-defended host plants through co-option of chemosensory capabilities already present in their ancestors.

Identification of flame transfer functions during transient operation

Predicting thermoacoustic instabilities requires knowledge of the flame response to acoustic perturbations, which is characterized by the Impulse Response Function. Obtaining stability maps across an extensive parameter space is prohibitively costly with existing methods, both experimentally and numerically, as the data records must be obtained independently for each stationary operating condition. To address this problem, a nonparametric identification technique that enables the characterization of instantaneous Flame Transfer Functions (FTFs) under nonstationary operating conditions, based on a series expansion of the time-varying impulse response function (TV-IRF), is proposed. The technique is a direct extension of the Wiener-Hopf equation to nonstationary signals, yielding the linear minimum mean squared error estimator (LMMSEE) of the TV-IRF. This method is applied to data obtained from a model of a premixed, hydrogen-enriched swirl flame. It's hydrogen power fraction is rapidly varied from 12-43% over 100 milliseconds and the flame response to a band-limited, white-noise signal is computed. From the resulting input-output data, the TV-IRF is accurately estimated and the FTF for all hydrogen power fractions is obtained from a single data record. This method paves the way for cost-effective estimation of a map of FTF's from computational or experimental data, significantly reducing expenses in both cases.

Variable preservation of the 1991 Hudson tephra in small lakes and on land

Volcanic ash (tephra) preserved in terrestrial environments and lake sediments contains information about volcanic processes and can be used to infer eruptive parameters and frequency of past eruptions, contributing to the understanding of volcanic hazards. However, tephra deposits can undergo transformation from their initial fallout sedimentation to being preserved as a tephra layer in the sedimentary record. The process is likely to be different in lakes and in terrestrial (soil) sequences. Here we compare the thickness, mass loading and grain size of tephra layers from the 1991 eruption of Cerro Hudson, Chile, from small lakes and adjacent terrestrial settings to measurements of the tephra made shortly after the eruption. We analysed samples from 35 cores in total from six small lakes (<0.25 km2), located 76 and 109 km from the volcano in two contrasting climatic areas (cool and humid northern site, and warm and dry southern site), and made 73 measurements of tephra thickness and 11 measurements of grain size in adjacent terrestrial areas. The major element geochemistry of our samples confirmed they were from the 1991 Hudson eruption. We found that some of the measured characteristics of the preserved tephra layers were comparable to those recorded in 1991 shortly after initial deposition, but that there was considerable variability within and between locations. This variability was not predictable and lake sediments did not preserve a notably more accurate record of the fallout than terrestrial sites. However, in aggregate the characteristics of the preserved tephra was similar to those recorded at the time of deposition, suggesting that, for palaeotephra research, a sampling strategy involving a wide range of environments is more robust than one that relies on a single sedimentary record or a single type of sedimentary environment.

Heterodyne background-oriented schlieren for the measurement of thermoacoustic oscillations in flames

In aircraft engines, thermoacoustic oscillations in the combustion chamber contribute significantly to noise emissions, which, like all other emissions, must be drastically reduced. Thermoacoustic oscillations are not only a concern, they can also be beneficial in hydrogen combustion. This work demonstrates that thermoacoustic density oscillations with amplitudes at least an order of magnitude smaller than those resulting from density gradients in a turbulent flame can be detected using laser interferometric vibrometry. This improvement was made possible by heterodyning a carrier fringe system in background-oriented schlieren (BOS) recordings, which were subsequently analyzed using techniques commonly used for holographic interferometry. In comparison with other BOS evaluation techniques, the filtering of the individual frames in the Fourier domain offers a more efficient computational approach, as it allows for phase averaging of a high number of single recordings to reduce noise from turbulence. To address fringe pattern distortions and cross talk in the Fourier domain, which both have been observed by other authors, we propose background subtraction methods and an optimized background pattern. Additionally, the procedure provides a visualization tool for marking the high turbulence regions of heat release by the variations in fringe amplitude. Finally, the line-of-sight data are reconstructed using the inverse Abel transform, with the data calibrated by laser interferometric techniques, resulting in local values for density oscillations.Graphical abstract

Nocturnal blood pressure dipping and left ventricular hypertrophy among hypertensive outpatients in a Ghanaian hospital.

To investigate the association between the extent of nocturnal systolic blood pressure decline and left ventricular hypertrophy in patients with primary hypertension who were receiving antihypertensive drug therapy. This was a cross-sectional hospital-based study from November 2020 to March 2021. The study was conducted at the Polyclinic of Korle Bu Teaching Hospital, Ghana. Outpatients ≥18 years old with primary hypertension who were receiving antihypertensive drug therapy. Each participant underwent a 24-hour ambulatory blood pressure monitoring and a transthoracic echocardiogram. Left ventricular hypertrophy and the extent of mean systolic blood pressure decline during sleep. 180 participants were recruited, comprising 110 (61.1%) females. The participants' mean (±SD) age was 57.6 ± 11.0 years. 80% had a non-dipping blood pressure pattern, and 43.9% had left ventricular hypertrophy. Uncontrolled office blood pressure was an independent predictor of left ventricular hypertrophy in these patients (AOR 2.010, 95% CI 1.048-3.855, p=0.036); however, a non-dipping nocturnal systolic blood pressure status was not (AOR 1.849, 95% CI 0.850-4.022, p=0.121). 61.1% had abnormal left ventricular geometry, with concentric hypertrophy being the predominant geometric pattern. Left ventricular hypertrophy and non-dipping nocturnal blood pressure were common in these hypertensive Ghanaian patients on antihypertensive therapy. Left ventricular hypertrophy was associated with uncontrolled office blood pressure but not the extent of nocturnal systolic blood pressure declines during a single 24-hour ambulatory blood pressure recording. None declared.

Reliability of crackles in fibrotic interstitial lung disease: a prospective, longitudinal study

BackgroundAlthough crackles on chest auscultation represent a fundamental component of the diagnostic suspect for fibrotic interstitial lung disease (ILD), their reliability has not been properly studied. We assessed the agreement among respiratory physicians on the presence and changes over time of audible crackles collected in a prospective longitudinal cohort of patients with fibrotic ILD.MethodsLung sounds were digitally recorded at baseline and after 12 months at eight anatomical sites. Nine respiratory physicians blindly assessed randomized couples of recordings obtained from the same anatomical site at different timepoints. The physicians indicated the presence of crackles in individual recordings and which recording from each couple eventually had more intense crackles. Fleiss’ kappa coefficient was used to measure inter- and intra-rater agreement.ResultsFifty-two patients, mostly with a diagnosis of IPF (n = 40, 76.9%) were prospectively enrolled between October 2019 and May 2021. The final acoustic dataset included 702 single recordings, corresponding to 351 couples of recordings from baseline and 12-months timepoints. Kappa coefficient was 0.57 (95% CI 0.55–0.58) for the presence of crackles and 0.42 (95% CI 0.41–0.43) for acoustic change. Intra-rater agreement, measured for three respiratory physicians on three repeated assessments, ranged from good to excellent for the presence of crackles (κ = 0.87, κ = 0.86, κ = 0.79), and from moderate to good for acoustic change (κ = 0.75, κ = 0.76, κ = 0.57).ConclusionsAgreement between respiratory physicians for the presence of crackles and acoustic change was acceptable, suggesting that crackles represent a reliable acoustic finding in patients with fibrotic ILD. Their role as a lung-derived indicator of disease progression merits further studies.

Comparison of orientation encoding across layers within single columns of primate V1 revealed by high-density recordings.

Primary visual cortex (V1) has been the focus of extensive neurophysiological investigations, with its laminar organization serving as a crucial model for understanding the functional logic of neocortical microcircuits. Utilizing newly developed high-density, Neuropixels probes, we measured visual responses from large populations of simultaneously recorded neurons distributed across layers of macaque V1. Within single recordings, myriad differences in the functional properties of neuronal subpopulations could be observed. Notably, while standard measurements of orientation selectivity showed only minor differences between laminar compartments, decoding stimulus orientation from layer 4C responses outperformed both superficial and deep layers within the same cortical column. The superior orientation discrimination within layer 4C was associated with greater response reliability of individual neurons rather than lower correlated activity within neuronal populations. Our results underscore the efficacy of high-density electrophysiology in revealing the functional organization and network properties of neocortical microcircuits within single experiments.

Functional efficacy of the MAO-B inhibitor safinamide in murine substantia nigra pars compacta dopaminergic neurons in vitro: A comparative study with tranylcypromine

Safinamide (SAF) is currently used to treat Parkinson's disease (PD) symptoms based on its theoretical ability to potentiate the dopamine (DA) signal, blocking monoamine oxidase (MAO) B. The present work aims to highlight the functional relevance of SAF as an enhancer of the DA signal, by evaluating its ability to prolong recovery from DA-mediated firing inhibition of DAergic neurons of the substantia nigra pars compacta (SNpc), compared to another MAO antagonist, tranylcypromine (TCP). Using multielectrode array (MEA) and single electrode extracellular recordings of spontaneous spikes from presumed SNpc DAergic cells in vitro, we show that SAF (30 μM) mildly prolongs the DA-mediated firing inhibition, as opposed to the profound effect of TCP (10 μM). In patch-clamp recordings, we found that SAF (30 μM) significantly reduced the number of spikes evoked by depolarizing currents in SNpc DAergic neurons, in a sulpiride (1 μM) independent manner. According to our results, SAF marginally potentiates the DA signal in SNpc DAergic neurons, while exerting an inhibitory effect on the postsynaptic excitability acting on membrane conductances. Thus, we propose that the therapeutic effects of SAF in PD patients partially depends on MAO inhibition, while other MAO-independent sites of action could be more relevant.