Lung Auscultation of Hospitalized Patients with SARS-CoV-2 Pneumonia via a Wireless Stethoscope.

Objective: SARS-CoV-2 (originally named COVID-2019) pneumonia is currently prevalent worldwide. The number of cases has increased rapidly but the auscultatory characteristics of affected patients and how to use it to predict who is most likely to survive or die are not available. This study aims to describe the auscultatory characteristics and its clinical relativity of SARS-CoV-2 pneumonia by using a wireless stethoscope. Material and methods: A cross-sectional, observational, single-center case series of 30 consecutive hospitalized patients with confirmed SARS-CoV-2 pneumonia at Leishenshan Hospital in Wuhan, China, were enrolled from March 9 to April 5, 2020. Clinical, laboratory, radiological, treatment data and lung auscultation were collected and analyzed. Lung auscultation was acquired by a wireless electronic stethoscope. Auscultatory characteristics of the moderate, severe, and critically ill patients were compared. Results: Kinds of crackles including fine crackles and wheezing were heard and recorded in these patients. Velcro crackles were heard in most critically ill patients (6/10). Besides, patients with Velcro crackles were all dead (6/6). There was no positive lung auscultatory finding in the moderate group and little positive lung auscultatory findings (4/10) in the severe group. Conclusion: Velcro crackles can be auscultated by this newly designed electronic wireless stethoscope in most critically ill patients infected by SARS-CoV-2 and predicts a poor prognosis. Moderate and severe patients without positive auscultatory findings may have a better prognosis.

Unwrapping the phase portrait features of adventitious crackle for auscultation and classification: a machine learning approach.

The paper delves into the plausibility of applying fractal, spectral, and nonlinear time series analyses for lung auscultation. The thirty-five sound signals of bronchial (BB) and pulmonary crackle (PC) analysed by fast Fourier transform and wavelet not only give the details of number, nature, and time of occurrence of the frequency components but also throw light onto the embedded air flow during breathing. Fractal dimension, phase portrait, and sample entropy help in divulging the greater randomness, antipersistent nature, and complexity of airflow dynamics in BB than PC. The potential of principal component analysis through the spectral feature extraction categorises BB, fine crackles, and coarse crackles. The phase portrait feature-based supervised classification proves to be better compared to the unsupervised machine learning technique. The present work elucidates phase portrait features as a better choice of classification, as it takes into consideration the temporal correlation between the data points of the time series signal, and thereby suggesting a novel surrogate method for the diagnosis in pulmonology. The study suggests the possible application of the techniques in the auscultation of coronavirus disease 2019 seriously affecting the respiratory system.

Effects of Temperature on Bending Properties of Three-Dimensional and Five-Directional Braided Composite.

The bending properties of three-dimensional (3Dim) and five-directional (5Dir) braided/epoxy resin composites at room temperature, 90 °C, 110 °C, and 150 °C and heating for 0.25 h, 10 h, and 30 h, respectively, were studied. The effect of different temperatures and heating times on the bending property of these composites was discussed. The results showed that the bending strength of these composites at 90 °C, 110 °C, and 150 °C and heating time of 0.25 h is 33.86%, 46.27%, and 83.94% lower, respectively, than that at room temperature. In addition, 3Dim-5Dir braided composites exhibit different damage modes at different temperatures, revealing different failure mechanisms. Heating temperature has greater influence on the bending properties of these composites than heating time. The results provided a basis for the application of resin-based 3Dim-5Dir braided/epoxy resin composites at different temperatures.

Transparent and Flexible Supercapacitors with Networked Electrodes.

Transparent and flexible energy storage devices have received immense attention due to their suitability for innovative electronics and displays. However, it remains a great challenge to fabricate devices with high storage capacity and high degree of transmittance. This study describes a simple process for fabrication of supercapacitors with ≈75% of visible transparency and areal capacitance of ≈3 mF cm-2 with high stability tested over 5000 cycles of charging and discharging. The electrodes consist of Au wire networks obtained by a simple crackle template method which are coated with MnO2 nanostructures by electrodeposition process. Importantly, the membrane separator itself is employed as substrate to bring in the desired transparency and light weight while additionally exploiting its porous nature in enhancing the interaction of electrolyte with the active material from both sides of the substrate, thereby enhancing the storage capacity. The method opens up new ways for fabricating transparent devices.

Feasibility and Acceptability of Pediatric Smartphone Lung Auscultation by Parents: Cross-Sectional Study.

Background: The use of a smartphone built-in microphone for auscultation is a feasible alternative to the use of a stethoscope, when applied by physicians. Objective: This cross-sectional study aims to assess the feasibility of this technology when used by parents-the real intended end users. Methods: Physicians recruited 46 children (male: n=33, 72%; age: mean 11.3, SD 3.1 y; children with asthma: n=24, 52%) during medical visits in a pediatric department of a tertiary hospital. Smartphone auscultation using an app was performed at 4 locations (trachea, right anterior chest, and right and left lung bases), first by a physician (recordings: n=297) and later by a parent (recordings: n=344). All recordings (N=641) were classified by 3 annotators for quality and the presence of adventitious sounds. Parents completed a questionnaire to provide feedback on the app, using a Likert scale ranging from 1 ("totally disagree") to 5 ("totally agree"). Results: Most recordings had quality (physicians' recordings: 253/297, 85.2%; parents' recordings: 266/346, 76.9%). The proportions of physicians' recordings (34/253, 13.4%) and parents' recordings (31/266, 11.7%) with adventitious sounds were similar. Parents found the app easy to use (questionnaire: median 5, IQR 5-5) and were willing to use it (questionnaire: median 5, IQR 5-5). Conclusions: Our results show that smartphone auscultation is feasible when performed by parents in the clinical context, but further investigation is needed to test its feasibility in real life.

Regularity and mechanism of fake crackle noise in an electronic stethoscope.

Background: Electronic stethoscopes are widely used for cardiopulmonary auscultation; their audio recordings are used for the intelligent recognition of cardiopulmonary sounds. However, they generate noise similar to a crackle during use, significantly interfering with clinical diagnosis. This paper will discuss the causes, characteristics, and occurrence rules of the fake crackle and establish a reference for improving the reliability of the electronic stethoscope in lung auscultation. Methods: A total of 56 participants with healthy lungs (no underlying pulmonary disease, no recent respiratory symptoms, and no adventitious lung sound, as confirmed by an acoustic stethoscope) were enrolled in this study. A 30-s audio recording was recorded from each of the nine locations of the larynx and lungs of each participant with a 3M Littmann 3200 electronic stethoscope, and the audio was output in diaphragm mode and auscultated by the clinician. The doctor identified the fake crackles and analyzed their frequency spectrum. High-pass and low-pass filters were used to detect the frequency distribution of the fake crackles. Finally, the fake crackle was artificially regenerated to explore its causes. Results: A total of 500 audio recordings were included in the study, with 61 fake crackle audio recordings. Fake crackles were found predominantly in the lower lung. There were significant differences between lower lung and larynx (p < 0.001), lower lung and upper lung (p = 0.005), lower lung and middle lung (p = 0.005), and lower lung and infrascapular region (p = 0.027). Furthermore, more than 90% of fake crackles appeared in the inspiratory phase, similar to fine crackles, significantly interfering with clinical diagnosis. The spectral analysis revealed that the frequency range of fake crackles was approximately 250-1950 Hz. The fake crackle was generated when the diaphragm of the electronic stethoscope left the skin slightly but not completely. Conclusion: Fake crackles are most likely to be heard when using an electronic stethoscope to auscultate bilateral lower lungs, and the frequency of a fake crackle is close to that of a crackle, likely affecting the clinician's diagnosis.

Classification of lung sounds using scalogram representation of sound segments and convolutional neural network.

Lung auscultation is one of the most common methods for screening of lung diseases. The increasingly high rate of respiratory diseases leads to the need for robust methods to detect the abnormalities in patients' breathing sounds. Lung sounds analysis stands out as a promising approach to automatic screening of lung diseases, serving as a second opinion for doctors as a stand-alone device for preliminary screening of lung diseases in remote areas. In previous research on lung classification using ICBHI Database on Kaggle, lung audios are converted to spectral images and fed into deep neural networks for training. There are a few studies which uses the scalogram, however they focussed on classification among different lung diseases. The use of scalograms in categorising the sound types are rarely used. In this paper, we combined scalograms and neural networks for classification of lung sound types. Padding methods and augmentation are also considered to evaluate the impacts on classification score. An ensemble learning is incorporated to increase classification accuracy by utilising voting of many models. The model trained and evaluated has shown prominent improvement of this method on classification on the benchmark ICBHI database.

LungAttn: advanced lung sound classification using attention mechanism with dual TQWT and triple STFT spectrogram.

Objective. Auscultation of lung sound plays an important role in the early diagnosis of lung diseases. This work aims to develop an automated adventitious lung sound detection method to reduce the workload of physicians.Approach. We propose a deep learning architecture, LungAttn, which incorporates augmented attention convolution into ResNet block to improve the classification accuracy of lung sound. We adopt a feature extraction method based on dual tunableQ-factor wavelet transform and triple short-time Fourier transform to obtain a multi-channel spectrogram. Mixup method is introduced to augment adventitious lung sound recordings to address the imbalance dataset problem.Main results. Based on the ICBHI 2017 challenge dataset, we implement our framework and compare with the state-of-the-art works. Experimental results show that LungAttn has achieved theSensitivity, Se,Specificity, SpandScoreof 36.36%, 71.44% and 53.90%, respectively. Of which, our work has improved theScoreby 1.69% compared to the state-of-the-art models based on the official ICBHI 2017 dataset splitting method.Significance. Multi-channel spectrogram based on different oscillatory behavior of adventitious lung sound provides necessary information of lung sound recordings. Attention mechanism is introduced to lung sound classification methods and has proved to be effective. The proposed LungAttn model can potentially improve the speed and accuracy of lung sound classification in clinical practice.

Resonance based separation and energy based classification of lung sounds using tunable wavelet transform.

BACKGROUND AND OBJECTIVE: The locations and occurrence pattern of adventitious sounds in the respiratory cycle have critical diagnostic information. In a lung sound sample, the crackles and wheezes may exist individually or they may coexist in a successive/overlapping manner superimposed onto the breath noise. The performance of the linear time-frequency representation based signal decomposition methods has been limited in the crackle/wheeze separation problem due to the common signal components that may arise in both time and frequency domain. However, the proposed resonance based decomposition can be used to isolate crackles and wheezes which behave oppositely in time domain even if they share common frequency bands. METHODS: In the proposed study, crackle and/or wheeze containing synthetic and recorded lung-sound signals were decomposed by using the resonance information which is produced by joint application of the Tunable Q-factor Wavelet Transform and Morphological Component Analysis. The crackle localization and signal reconstruction performance of the proposed approach was compared with the previously suggested Independent Component Analysis and Empirical Mode Decomposition methods in a quantitative and qualitative manner. Additionally, the decomposition ability of the proposed approach was also used to discriminate crackle and wheeze waveforms in an unsupervised way by employing signal energy. RESULTS: Results have shown that the proposed approach has significant superiority over its competitors in terms of the crackle localization and signal reconstruction ability. Moreover, the calculated energy values have revealed that the transient crackles and rhythmic wheezes can be successfully decomposed into low and high resonance channels by preserving the discriminative information. CONCLUSIONS: It is concluded that previous works suffer from deforming the waveform of the crackles whose time domain parameters are vital in computerized diagnostic classification systems. Therefore, a method should provide automatic and simultaneous decomposition ability, with smaller root mean square error and higher accuracy as demonstrated by the proposed approach.

A leaf vein-like hierarchical silver grids transparent electrode towards high-performance flexible electrochromic smart windows.

As essential components of numerous flexible and wearable optoelectronic devices, the flexible transparent conducting electrodes (TCEs) with sufficient optical transmittance and electric conductivity become more and more important. In this work, we fabricated a large-area flexible TCE based on leaf vein-like hierarchical metal grids (HMG) comprising of mesoscale "trunk" and microscale "branches". The self-formed branched grids made the conducting paths distributing uniformly while the laser-etching trunk grids enabled to transport the collected electrons across long-distance. The Ag HMG exhibited high optical transmittance (~81%) with low sheet resistance (1.36 Ω sq-1), which could be simply optimized through adjusting the grids' widths, spaces, and the sizes of the TiO2 colloidal crackle patterns. In addition, on the basis of such advanced HMG electrode, flexible electrochromic devices (ECDs) with remarkable cyclic performance were fabricated. The HMG with high transparency, conductivity, and flexibility provides a promising TCE for the next-generation flexible and wearable optoelectronic devices.

Cosmetically Adaptable Transparent Strain Sensor for Sensitively Delineating Patterns in Small Movements of Vital Human Organs.

Monitoring live movements of human body parts is becoming increasingly important in the context of biomedical and human machine technologies. The development of wearable strain sensors with high sensitivity and fast response is critical to address this need. In this article, we describe the fabrication of a wearable strain sensor made of a Au micromesh partially embedded in polydimethylsiloxane substrate. The sensor exhibits a high optical transmittance of 85%. The effective strain range for stretching is 0.02%-4.5% for a gauge factor of over 108. In situ scanning electron imaging and infrared thermal microscopy analysis have revealed that nanometric break junctions form throughout the wire network under strain; strain increases the number of such junctions, leading to a large change in the sheet resistance of the mesh. This aspect has been examined computationally with the findings that wire segments break successively with increasing strain and resistance increases linearly for lower values of strain and nonlinearly at higher values of strain because of formation of current bottlenecks. The semi-embedded nature of these Au microwires allows the broken wires to retract to the original positions, thus closing the nanogaps and regaining the original low resistance state. High repeatability as well as cyclic stability have been demonstrated in live examples involving human body activity, importantly while mounting the sensor in strategic remote locations away from the most active site where strains are highest.

Analysis of pulmonary sounds for the diagnosis of interstitial lung diseases secondary to rheumatoid arthritis.

The diagnosis of interstitial lung diseases in patients affected by rheumatoid arthritis is fundamental to improving their survival rate. In particular, the average survival time of patients affected by rheumatoid arthritis with pulmonary implications is approximately 3 years. The gold standard for confirming the diagnosis of this disease is computer tomography. However, it is very difficult to raise diagnosis suspicion because the symptoms of the disease are extremely common in elderly people. The detection of the so-called velcro crackle in lung sounds can effectively raise the suspicion of an interstitial disease and speed up diagnosis. However, this task largely relies on the experience of physicians and has not yet been standardized in clinical practice. The diagnosis of interstitial lung diseases based on thorax auscultation still represents an underexplored field in the study of rheumatoid arthritis. In this study, we investigate the problem of the automatic detection of velcro crackle in lung sounds. In practice, the patient is auscultated using a digital stethoscope and the lung sounds are saved to a file. The acquired digital data are then analysed using a suitably developed algorithm. In particular, the proposed solution relies on the empirical observation that the audio bandwidth associated with velcro crackle is larger than that associated with healthy breath sounds. Experimental results from a database of 70 patients affected by rheumatoid arthritis demonstrate that the developed tool can outperform specialized physicians in terms of diagnosing pulmonary disorders. The overall accuracy of the proposed solution is 90.0%, with negative and positive predictive values of 95.0% and 83.3%, respectively, whereas the reliability of physician diagnosis is in the range of 60-70%. The devised algorithm represents an enabling technology for a novel approach to the diagnosis of interstitial lung diseases in patients affected by rheumatoid arthritis.

Highly Conformal Ni Micromesh as a Current Collecting Front Electrode for Reduced Cost Si Solar Cell.

Despite relatively high manufacturing cost, crystalline-Si solar cell continues to hold promising future due to its high energy conversion efficiency and long life. As regards cost, one pertinent issue is the top electrode metallization of textured cell surface, which typically involves screen printing of silver paste. The associated disadvantages call for alternative methods that can lower the cost without compromising the solar cell efficiency. In the present work, a highly interconnected one-dimensional (1D) metal wire network has been employed as front electrode on conventional Si wafers. Here, for the first time, we report an innovative solution based crackle templating method for conformal metal wire network patterning over large textured surfaces. Laser beam induced current mapping showed uniform photocurrent collection by the electrodes without any shadow losses. With electroless deposition of Ni wire network on corrugated solar cell, a short circuit current of 33.28 mA/cm2 was obtained in comparison to 20.53 mA/cm2 without the network electrode. On comparing the efficiency with the conventional cells with screen printed electrodes, a 20% increment in efficiency has been observed. Importantly, the estimated manufacturing cost is at least two orders lower.

Fabrication of Oxidation-Resistant Metal Wire Network-Based Transparent Electrodes by a Spray-Roll Coating Process.

Roll and spray coating methods have been employed for the fabrication of highly oxidation resistant transparent and conducting electrodes (TCEs) by a simple solution process using crackle lithography technique. We have spray-coated a crackle paint-based precursor to produce highly interconnected crackle network on PET roll mounted on a roll coater with web speed of 0.6 m/min. Ag TCE with a transmittance of 78% and sheet resistance of ∼20 Ω/□ was derived by spraying Ag precursor ink over the crackle template followed by lift-off and annealing under ambient conditions. The Ag wire mesh was stable toward bending and sonication tests but prone to oxidation in air. When electrolessly coated with Pd, its robustness toward harsh oxidation conditions was enhanced. A low-cost transparent electrode has also been realized by using only small amounts of Ag as seed layer and growing Cu wire mesh by electroless method. Thus, made Ag/Cu meshes are found to be highly stable for more than a year even under ambient atmosphere.

Dispneia expiratória restritiva em um gato com fibrose pulmonar idiopática: relato de caso / Restrictive expiratory dyspnea in a cat with idiopathic pulmonary fibrosis: case report

As doenças pulmonares intersticiais constituem um grupo de doenças difusas do parênquima pulmonar, no qual a fibrose pulmonar intersticial está incluída. Histologicamente, esta se caracteriza por hiperplasia de pneumócitos tipo II, hiperplasia ou hipertrofia de músculo liso e fibrose. Embora a patogenia da fibrose pulmonar intersticial não esteja bem elucidada, devido às semelhanças microscópicas encontradas nos pneumócitos tipo II em felinos e na forma familiar da doença em humanos, acredita-se que haja caráter genético para o seu desenvolvimento. Os sinais clínicos frequentemente relatados incluem desconforto respiratório, cianose, letargia e perda de peso. Devido ao caráter progressivo e à ausência de tratamento específico, a doença apresenta prognóstico desfavorável. Foi atendida uma gata de 12 anos de idade, com histórico de dispneia há 20 dias. Ao exame clínico, o animal apresentou dispneia expiratória restritiva, crepitação à ausculta torácica e foi visualizado padrão intersticial ao exame radiográfico do tórax. A paciente foi submetida à punção com agulha fina de tecido pulmonar e veio a óbito algumas horas após o procedimento, apresentando insuficiência respiratória aguda. No exame histológico do tecido pulmonar, foi verificada a ocorrência de fibrose pulmonar idiopática. O objetivo do presente trabalho é relatar um caso de dispneia expiratória restritiva em um felino doméstico devido à fibrose pulmonar idiopática, já que, segundo o conhecimento dos autores, não há nenhum relato da ocorrência da doença no país.(AU)

Interstitial lung diseases are a group of diffuse parenchymal lung diseases in which interstitial lung fibrosis is included. Histologically, it is characterized by type II pneumocyte hyperplasia, hypertrophy or hyperplasia of smooth tissue and fibrosis. Although the pathogenesis of interstitial lung fibrosis has not been elucidated, due to the microscopic similarities found in type II pneumocytes in cats and familial form of the disease in humans, it is believed that there is a genetic trait for development. The frequently reported clinical signs include respiratory distress, cyanosis, lethargy, and weight loss. Due to the progressive nature and the absence of specific treatment, the disease has a poor prognosis. A 12-year-old cat with dyspnea for 20 days was assisted. The animal underwent fine needle aspiration of lung tissue and died few hours after the procedure, with acute respiratory failure. Upon histological examination of lung tissue, the occurrence of idiopathic pulmonary fibrosis was found. The aim of this study is to report a case of restrictive expiratory dyspnea in a domestic feline due to idiopathic pulmonary fibrosis, because, according to our knowledge, there is no report on the occurrence of the disease in our country.(AU)