ARTICLE | doi:10.20944/preprints201808.0161.v1
Subject: Engineering, Control & Systems Engineering Keywords: photoplethysmography (PPG); respiration rate; information filter
Online: 8 August 2018 (06:09:31 CEST)
In this work, an algorithm was developed to measure the respiration rate for an embedded device that can be used by a field robot for relief operation. With this algorithm, the rate measurement was calculated based on direct influences of respiratory-induced intensity variation (RIIV) on blood flow in cardiovascular pathways. For that, a photoplethysmogram (PPG) sensor was used to determine changes in heartbeat frequencies. The PPG sensor readings were filtered using an Information Filter and a Fast Fourier transform (FFT) to determine the state of RIIV. With a relatively light initialization, the information filter can estimate unknown variables based on a series of measurements containing noise and other inaccuraties. Therefore, this filter is suitable for application on an embedded device. For faster calculation time in the implementation, the FFT analysis was calculated only for a major peak in the frequency domain. Test and measurement of respiration rate was conducted based on the device algorithm and spirometer. Heartbeat measurement was also evaluated by comparing the heartbeat data of the PPG sensor and the medical tool kit. Based on the test, the implemented algorithm can measure respiration rate with about 80% accuracy compared with the spirometer.
REVIEW | doi:10.20944/preprints202105.0070.v1
Subject: Behavioral Sciences, Other Keywords: HRV; Biosignals; ECG; Respiration; Psychophysiology; Psychology; NeuroKit2
Online: 5 May 2021 (15:11:08 CEST)
The use of heart rate variability (HRV) in research has been greatly popularized over the past decades due to the ease and affordability of HRV collection, coupled with its clinical relevance and significant relationships with psychophysiological constructs and psychopathological disorders. Despite the wide use of electrocardiogram (ECG) in research and advancement in sensors technology, the analytical approach and steps applied to obtain HRV measures can be seen as complex. Thus, posing a challenge to users who may not have the adequate background knowledge to obtain the HRV indices reliably. To maximize the impact of HRV-related research and its reproducibility, parallel advances in users’ understanding of the indices and the standardization of analysis pipelines in its utility will be crucial. This paper addresses this gap and aims to provide an overview of the most up-to-date and commonly used HRV indices, as well as common research areas that these indices have shown to be very useful, particularly in psychology. In addition, we also provide a step-by-step guide on how to perform HRV analysis using an integrative neurophysiological toolkit, NeuroKit2.
ARTICLE | doi:10.20944/preprints201706.0079.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: wearable; photoplethysmography; spectral kurtosis; extreme learning machine (ELM) regression; respiration rate; cardiovascular diseases (CVD)
Online: 16 June 2017 (10:45:32 CEST)
In this paper, we present the design of a wearable photoplethysmography (PPG) system, R-band for acquiring the PPG signals. PPG signals are influenced by the respiration or breathing process and hence can be used for estimation of respiration rate. R-Band detects the PPG signal that is routed to a Bluetooth low energy device such as a nearbyplaced smartphone via microprocessor. Further, we developed an algorithm based on Extreme Learning Machine (ELM) regression for the estimation of respiration rate. We proposed spectral kurtosis features that are fused with the state-ofthe-art respiratory-induced amplitude, intensity and frequency variations-based features for the estimation of respiration rate (in units of breaths per minute). In contrast to the neural network (NN), ELM does not require tuning of hidden layer parameter and thus drastically reduces the computational cost as compared to NN trained by the standard backpropagation algorithm. We evaluated the proposed algorithm on Capnobase data available in the public domain.
CASE REPORT | doi:10.20944/preprints202110.0386.v1
Subject: Medicine & Pharmacology, Anesthesiology Keywords: Atelectasis; Hypoxia; Old age; Spontaneous respiration
Online: 26 October 2021 (12:36:47 CEST)
There are several causes of hypoxia during and after surgery, and atelectasis is a common symptom that occurs during surgery. In particular, elderly patients are more vulnerable to hypoxia due to their existing lung diseases or respiratory muscle weakness. This study presents the cases of two elderly patients who developed hypoxia during total hip arthroplasty under general anesthesia. Positive end expiratory pressure, recruitment maneuver, and increased fraction of inspired oxygen improved hypoxia only temporarily, and patients’ oxygen saturation level again dropped to 79%–80%. We suspected that hypoxia was caused by atelectasis and, therefore, re-sumed spontaneous respiration. Thereafter, both the patients showed an improvement in hypoxia. Intraopera-tive hypoxia that is suspected to be caused by atelectasis can be improved by securing sufficient lung volume for respiration through increased muscle tone with spontaneous respiration
ARTICLE | doi:10.20944/preprints201910.0201.v2
Online: 25 October 2019 (11:32:14 CEST)
Background: While investigating the real-time impedance at acupuncture points (acupoints), it was found that regular sinusoidal waves were present that corresponded to the pulsing of certain organs, such as respiration and duodenal waves, the stomach’s slow waves, and also the heart’s beating.Methods: This study investigated such respiration waves at lung-related acupoints to clarify their relation to the respiration pacesetter mechanism. The impedance at key acupoints was monitored in real time while the patients’ breathing slowed after exercise.Results: In all 7 patients studied, the respiration and heart-beat waves matched the rates in the corresponding organs at rest, and did not vary markedly due to exercise. In 3 of the 7 patients, their post-exercise respiration rate exactly matched that of their duodenal waves, but then dropped, stepwise, back to their usual respiration rate. In the other 4 patients, their post-exercise respiration rate did not reach that of their duodenal waves, so this pattern was not triggered.Conclusion: The results suggested that as well as the brainstem respiration pacesetter, there was also a separate “pace signal” present which remained constant and seemed to define the respiration rate when at rest. It is currently unknown what mechanism causes the respiration rate to increase due to exercise. But these results suggest that the brainstem pacesetter is sometimes guided by the duodenal pace signal instead of the lung pace signal, which may explain how the pacesetter is able to jump to a higher rate, even though its chemoreceptor inputs may be unchanged.
ARTICLE | doi:10.20944/preprints202210.0283.v1
Online: 19 October 2022 (10:26:48 CEST)
γ-Aminobutyric acid (GABA) plays an important role in plant development and postharvest properties of fruits. However, studies on regulation of kiwifruit ripening by GABA are scarce. Here, we evaluted physicochemical characters and the expression profile of genes related to ripening in hardy kiwifruit treated with exogenous GABA compared to control during postharvest storage period. The results showed that (1) exogenous GABA treatment not only improved the fruit quality but also inhibited respiration rate and ethylene production, as well as reduced the enzyme activities of ACC oxidase (ACO) and ACC synthase (ACS), via down-regulating the expression of AaACO1 and AaACO3, AaACS1 and AaACS2 during kiwifruit storage period; (2) on the one hand, overexpression of AaGAD1 or AaGAD4 gene which is involved in GABA biosynthesis inhibited ethylene production by reducing the enzyme activities of ACO and ACS, whereas silencing of AaGAD1 or AaGAD4 gene led to the reverse effect. On the other hand, overexpression of AaGAD1 or AaGAD4 decreased the expression levels of AaACO1 and AaACO3, AaACS1 and AaACS2, whereas silencing of AaGAD1 or AaGAD4 gene increased the expression levels of these four genes. Above all, our findings demonstrate that exogenous GABA treatment could improve the storage quality and extend the shelf life of kiwifruit, Additionally, the content of GABA was participated in the regulation of ethylene biosynthesis at the molecular level.
ARTICLE | doi:10.20944/preprints201610.0054.v1
Subject: Life Sciences, Genetics Keywords: energy metabolism; respiration; fermentation; auxotrophy; retrograde response
Online: 14 October 2016 (10:58:50 CEST)
Background: The control of energy metabolism is fundamental for cell growth and function, and anomalies are implicated in complex diseases and ageing. It is important for cells to carefully tune metabolic pathways to optimize their function in response to different nutrient or physiological conditions. Metabolism in yeast cells can be easily manipulated by supplying different carbon sources: on glucose yeast rapidly proliferates by fermentation, analogous to tumour cells growing by aerobic glycolysis, whereas on non-fermentable carbon sources metabolism shifts towards respiration. Results: We screened deletion libraries of fission yeast to identify over 200 genes required for respiratory growth. The growth medium and auxotrophic mutants strongly influenced respiratory metabolism. Most genes uncovered in the mutant screens have not been implicated in respiration in budding yeast. We applied gene expression profiling approaches to compare steady-state fermentative and respiratory growth and to analyse the dynamic adaptation to respiratory growth. The transcript levels of most genes functioning in key energy metabolism pathways were coherently tuned, reflecting anticipated differences in metabolic flows between fermenting and respiring cells. We show that the acetyl-CoA synthase, rather than the citrate lyase, is essential for acetyl-CoA synthesis in fission yeast. We also investigated the transcriptional response to mitochondrial damage by genetic or chemical perturbations, defining a retrograde response that involves the concerted regulation of distinct groups of nuclear genes that may avert harm from mitochondrial malfunction. Conclusions: These systematic and targeted analyses provide a rich framework of the genetic and regulatory basis of fundamental metabolic states to guide future studies on energy metabolism in fission yeast and beyond. Our study pinpoints weaknesses of commonly used auxotroph mutants for investigating energy metabolism. As a model for cellular energy regulation, fission yeast provides an attractive and complementary system to budding yeast.
REVIEW | doi:10.20944/preprints202212.0273.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: Mint; Menthol; Digestion; Respiration; COVID-19; Sport; Pain
Online: 15 December 2022 (07:25:06 CET)
Mint and to a lesser extent menthol have been used since antiquity for medicinal purposes. Key components of mint and menthol use such as composition and intake, safety and traditional uses are discussed prior to a review of clinical and human performance outcomes in the areas of digestive and respiratory health; antibacterial and anti-fungal properties, nocioception, migraine and headache and emerging evidence regarding COVID 19. Evidence suggests benefit for patients with irritable bowel syndrome and related digestive issues, with analgesic and respiratory effects also noted. Perceptual characteristics relating to thermal comfort and sensation, taste sensitivity and alertness are also considered; these effects are predominantly driven by stimulation of transient receptor potential melastatin 8 (TRPM8) activity resulting in sensations of cooling and freshness, with lesser influence on thirst. Finally, sport performance is considered as a domain that may further elucidate some of the aforementioned underpinning outcomes due to its systemic and dynamic nature, especially when performed in hot environmental conditions.
ARTICLE | doi:10.20944/preprints202209.0062.v1
Subject: Life Sciences, Virology Keywords: antiviral response; ISGs; OXPHOS; mitochondrial respiration; metabolic reprogramming
Online: 5 September 2022 (13:13:18 CEST)
When exposed to a viral infection, the attacked cells promptly set up defence mechanisms. Part of antiviral responses, the innate immune interferon pathway and associated interferon stimulated genes are notably allowing the production of proteins bearing an antiviral activity. Numerous viruses are able to evade the interferon response, highlighting the importance of controlling this pathway to ensure their efficient replication. Several viruses are also known to manipulate the metabolism of infected cells to optimize the availability of amino acids, nucleotides and lipids. They then benefit from a reprogramming of the metabolism that favours glycolysis instead of mitochondrial respiration. Given the increasingly discussed crosstalk between metabolism and innate immunity, we wondered whether this switch from glycolysis to mitochondrial respiration would be beneficial or deleterious for an efficient antiviral response. We used a cell based model of metabolic reprogramming. Interestingly, we showed that increased mitochondrial respiration was associated with an enhanced interferon response following poly:IC stimulation. This suggests that during viral infection, the metabolic reprogramming towards glycolysis is also part of the virus' strategies to inhibit the antiviral response.
ARTICLE | doi:10.20944/preprints202106.0630.v1
Subject: Medicine & Pharmacology, Allergology Keywords: Exercise; Runners; Near-infrared spectroscopy; Respiratory muscles; Respiration.
Online: 28 June 2021 (09:44:55 CEST)
The study aimed to evaluate the association between the changes in ventilatory variables (tidal volume (Vt), respiratory rate (RR), and lung ventilation (VE)) and deoxygenation of m.intescostales (∆SmO2-m.intercostales) during a maximal incremental exercise in nineteen male competitive marathon runners. The ventilatory variables and oxygen-consumption (VO2) were recorded breath-by-breath by exhaled gas analysis. A near-infrared spectroscopy device (MOXY) located in the right-hemithorax allowed recording SmO2-m.intercostales. To explore changes in oxygen levels in muscles with high demand during exercise, a second MOXY records SmO2-m.vastus laterallis. The triphasic model of exercise intensity was used for evaluating changes in SmO2 in both muscle groups. We found that ∆SmO2-m.intercostales correlated with VO2-peak (r=0.65; p=0.002) and the increase of VE (r=0.78; p=0.001), RR (r=0.54; p=0.001), but not Vt (p=0.210). The interaction of factors (muscles X exercise-phases) in SmO2 expressed as an arbitrary unit (a.u) was significant (p=0.005). At VT1 were no difference (p=0.177), but SmO2-m.intercostales was higher at VT1 (p<0.001) and VO2-peak (p<0.001). In competitive marathon runners, the m.intercostales deoxygenation during incremental exercise is directly associated with the aerobic capacity and increased lung ventilation and respiratory rate, but not tidal volume. Besides, it shows less deoxygenation than m.vastus laterallis at intensities above the aerobic ventilatory threshold.
ARTICLE | doi:10.20944/preprints201703.0141.v3
Subject: Earth Sciences, Environmental Sciences Keywords: Forest ecosystem; Fluxnet; Soil respiration; Net ecosystem Exchange; Phenology
Online: 15 June 2017 (15:45:04 CEST)
Understanding the dynamics of Organic Carbon mineralization is fundamental in forecasting biosphere to atmosphere Net Carbon Ecosystem Exchange (NEE). With this perspective, we developed 3D-CMCC-PSM, a new version of the hybrid Process Based Model 3D‐CMCC FEM where also heterotrophic respiration (Rh) is explicitly simulated. The aim was to quantify NEE as a forward problem, by subtracting Ecosystem Respiration (Reco) to Gross Primary Productivity (GPP). To do so, we developed a simplification of the Soil Carbon dynamics routine proposed in DNDC . The method calculates decomposition as a function of soil moisture, temperature, state of the organic compartments, and relative abundance of microbial pools. Given the pulse dynamics of soil respiration, we introduced modifications in some of the principal constitutive relations involved in phenology and littering sub-routines. We quantified the model structure related uncertainty in NEE, by running our training simulations over 1000 random parameter-sets extracted from parameters distributions expected from literature. 3D-CMCC-PSM predictability was tested on independent time series for 6 Fluxnet sites. The model resulted in daily and monthly estimations highly consistent with the observed time series. It showed lower predictability in Mediterranean ecosystems, suggesting that it may need further improvements in addressing evapotranspiration and water dynamics.
ARTICLE | doi:10.20944/preprints202205.0161.v1
Subject: Medicine & Pharmacology, Clinical Neurology Keywords: Pineal cyst; hydrocephalus; microsurgery; real-time MRI; respiration; glymphatic system
Online: 12 May 2022 (08:00:41 CEST)
Proposal: Pineal region cysts (PCs) may affect the tectum and aqueduct and cause deep central vein congestion and endocrine dysfunction. In addition to headaches, PC often causes a broad range of symptoms, leading to prolonged diagnosis and therapy. The aims of this study are to reveal parameters that might explain the ambiguity of the symptoms and to identify factors association with the respiration driven neurofluid preload system. Methods: This retrospective study included 28 paediatric patients (mean age 11.6 years) who received surgical treatment for pineal region cysts and 18 patients (mean age 11.3 years) who were followed conservatively. Multiple clinical patient characteristics, such as symptoms, time to neuroimaging diagnosis, cyst size, ventricular indices, head circumference and postoperative outcome, were analysed. Four patients were investigated for CSF dynamics with real-time MRI. The mean follow-up time was 1.6 years. Results: The most common early onset symptoms were headaches (92%), blurred vision (42.8%), sleep disturbances (39.3%) and vertigo (32.1%). Tectum contact was observed in 82% of patients, and MRI examinations revealed that imaging flow void signals were absent in 32.1% of patients. The mean cyst diameters were 13.7 mm for the axial axis and 15.6 mm for the longitudinal axis. Together with a postoperative flow void signal, 4 patients recovered their respiration-driven CSF upward flow, which was not detectable before OP. After operation in 92.1% of patients, the leading symptoms improved without any mortality or morbidity. Conclusion: Despite proximity to the tectum and aqueduct with frequently absent aqueductal flow void signals, hydrocephalic ventricular enlargement was never detected. Data from real-time MRI depicted a reduced preoperative filling of the ventricular CSF compartments, indicating a diminished fluid preload, which recovered postoperatively.
REVIEW | doi:10.20944/preprints202010.0281.v1
Subject: Biology, Anatomy & Morphology Keywords: denitrification; evolution; thermophile; horizontal gene transfer; nitrate respiration; PacBio sequencing
Online: 13 October 2020 (14:00:29 CEST)
Genes coding for enzymes of the denitrification pathway appear randomly distributed among isolates of the ancestral genus Thermus, but only in few strains of the species T. thermophilus the pathway has been studied to a certain detail. Here, we review the enzymes involved in this pathway present in T. thermophilus NAR1, a strain extensively employed as a model for nitrate respiration, on the light of its full sequence recently assembled through a combination of PacBio and Illumina technologies in order to counteract the systematic errors introduced by the former technique. The genome of this strain is divided in four replicons, a chromosome of 2,021,843 pb, two megaplasmids of 370,865 and 77,135 bp and a small plasmid of 9,799 pb. Nitrate respiration is encoded in the largest megaplasmid, pTTHNP4, within a region that includes operons for O2 and nitrate sensory systems, a nitrate reductase, nitrate and nitrite transporters and a nitrate specific NADH dehydrogenase, in addition to multiple insertion sequences (IS), suggesting its mobility-prone nature. Despite nitrite is the final product of nitrate respiration in this strain, the megaplasmid encodes two putative nitrite reductases of the cd1 and Cu-containing types, apparently inactivated by IS. No nitric oxide reductase genes have been found within this region, although the NorR sensory gene, needed for its expression, is found near the inactive nitrite respiration system. These data clearly support that partial denitrification in this strain is the consequence of recent deletions and IS insertions in genes involved in nitrite respiration. Based on these data, the capability of this strain to transfer or acquire denitrification clusters by horizontal gene transfer is discussed.
ARTICLE | doi:10.20944/preprints201611.0003.v1
Subject: Biology, Plant Sciences Keywords: calcium; protons; exocytosis; tip growth; Lilium; pollen; respiration; perturbation analysis
Online: 1 November 2016 (05:25:42 CET)
Pollen tubes grow by spatially and temporally regulated expansion of new material secreted into the cell wall at the tip of the tube. A complex web of interactions among cellular components, ions and small molecule provides dynamic control of localized expansion and secretion. Cross-correlation studies on oscillating lily (Lilium formosanum Wallace) pollen tubes showed that an increase in intracellular calcium follows an increase in growth, whereas the increase in the alkaline band and in secretion both anticipate the increase in growth rate. Calcium, as a follower, is unlikely to be a stimulator of growth, whereas the alkaline band, as a leader, may be an activator. To gain further insight herein we reversibly inhibited growth with potassium cyanide (KCN), and followed the re-establishment of calcium, pH and secretion patterns as growth resumed. While KCN markedly slows growth and causes the associated gradients of calcium and pH to sharply decline, its removal allows growth and vital processes to fully recover. The calcium gradient reappears before growth restarts, however it is preceded by both the alkaline band and secretion, in which the alkaline band is slightly advanced over secretion. Thus the pH gradient, rather than the tip-focused calcium gradient, may regulate pollen tube growth.
ARTICLE | doi:10.20944/preprints201801.0280.v1
Subject: Biology, Plant Sciences Keywords: cold stress; heat stress; stress recovery; mitochondria; proteomics; respiration; Brassica; angiosperms
Online: 30 January 2018 (10:31:07 CET)
Complex proteomic and physiological approaches to study cold and heat stress responses in plant mitochondria are still limited. Variations in the mitochondrial proteome of cauliflower (Brassica oleracea var. botrytis) curds after cold and heat and after stress recovery were assayed by 2D PAGE in relation to respiratory parameters. Quantitative analysis of the mitochondrial proteome revealed numerous stress-affected protein spots. In cold alternative oxidase isoforms were extensively upregulated; major downregulations in the level of photorespiratory enzymes, porine isoforms, oxidative phosphorylation (OXPHOS) and some low-abundant proteins were observed. On the contrary, distinct proteins, including carbohydrate metabolism enzymes, heat-shock proteins, translation, protein import, and OXPHOS components were involved in heat response and recovery. Few metabolic regulations were suggested. Cauliflower plants appeared less susceptible to heat; closed stomata in heat stress resulted in moderate photosynthetic, but only minor respiratory impairments, however photosystem II performance was unaffected. Decreased photorespiration corresponded with proteomic alterations in cold. Our results show that cold and heat stress not only operate in diverse mode (exemplified by cold-specific accumulation of some heat shock proteins), but exert some associations on molecular and physiological levels. This implies more complex model of action of investigated stresses on plant mitochondria.
ARTICLE | doi:10.20944/preprints201712.0060.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: Clark-type oxygen sensor; mitochondrial respiration; amperometry; cyclic voltammetry; oocyte; embryo
Online: 11 December 2017 (07:18:46 CET)
Current commercially available instruments for monitoring mitochondrial respiration are incapable of single cell measurements. Therefore, we developed a three-electrode, Clark-type biosensor suitable for mitochondrial respirometry in single oocytes and embryos. The biosensor was embedded in a PMMA (polymethyl methacrylate) micro-chamber to allow investigation of single oocytes/embryos immersed in up to 100 µL of respiration buffer. The micro-chamber was completely sealed to avoid oxygen exchange between the inside of the chamber and the atmosphere, while being maintained at a temperature of 38.5 ˚C to preserve cell viability. Using amperometry, the oxygen consumption of cells inside the micro-chamber was measured as a change in output current and converted to femto-mol (fmol) oxygen consumed per second based on calibrations with known buffer oxygen concentrations. The sensor measured basal cell respiration supported by endogenous substrates, respiration associated with proton leak induced by inhibition of the adenosine triphosphate (ATP) synthase (complex V) with oligomycin, and the maximal non-coupled respiratory capacity revealed by Carbonyl cyanide-4-(trifluoromethoxy)phenylhydrazone (FCCP) titration. Some potential applications of this oxygen sensor system include evaluating effects of metabolic therapies on oocyte bioenergetics, and monitoring mitochondrial function throughout oocyte maturation and blastocyst development to predict embryo viability to compliment assisted reproductive technologies
ARTICLE | doi:10.20944/preprints202201.0113.v1
Subject: Biology, Plant Sciences Keywords: Group II; Intron; Splicing; PPR; Respiration; Complex I; Mitochondria; Embryogenesis; Arabidopsis; Angiosperms.
Online: 10 January 2022 (12:46:06 CET)
Mitochondria play key roles in cellular energy metabolism in eukaryotes. Mitochondria of most organisms contain their own genome and specific transcription and translation machineries. The expression of angiosperm mtDNA involves extensive RNA-processing steps, such as RNA trimming, editing, and the splicing of numerous group II-type introns. Pentatricopeptide repeat (PPR) proteins are key players of plant organelle gene expression and RNA metabolism. In the present analysis, we reveal the function of the MITOCHONDRIAL SPLICING FACTOR 2 gene (MISF2, AT3G22670) and show that it encodes a mitochondria-localized PPR protein that is crucial for early embryo-development in Arabidopsis. Molecular characterization of embryo-rescued misf2 plantlets indicates that the splicing of nad2 intron 1 and thus respiratory complex I biogenesis are strongly compromised. Moreover, the molecular function seems conserved between MISF2 protein in Arabidopsis and its orthologous gene (EMP10) in maize, suggesting that the ancestor of MISF2/EMP10 was recruited to function in nad2 processing before the monocot-dicot divergence, ~200 million years ago. These data provide new insights into the function of nuclear-encoded factors in mitochondrial gene expression and respiratory chain biogenesis during plant embryo development.
ARTICLE | doi:10.20944/preprints201804.0081.v1
Subject: Earth Sciences, Environmental Sciences Keywords: manometric tests; liquid phase test; SOUR; stability; organic substrates; respiration activity; respirometry
Online: 6 April 2018 (18:38:51 CEST)
The stability of twenty seven composts and organic substrates (including raw, less stable and stable materials) was assessed using two different liquid phase tests were carried out. One of the tests was introduced in 1998 and was based on the calculation of a Specific Oxygen Uptake Rate (SOUR). The newly introduced liquid phase test presented here is simpler to set-up and to perform that the older liquid phase test. It is based on the quantification of oxygen consumption in the headspace of a BOD bottle that contains the liquid-solid solution. The results indicate that a marginal correlation does exist between the main indices calculated from both tests. The correlation was stronger for the indices calculated for stable-processed organics than for the raw (unprocessed materials). The SOUR ranged from 1520 to 3650mg O2/kg VS-h for the raw materials and from 110 to 1150 mg O2/kg VS-h for the processed materials, respectively. The corresponding stability rate related index (LSRI24) of the new liquid phase test introduced here ranged from 240 to 1180 mg O2/dry kg-h for the raw materials and from 64 to 792 mg O2/dry kg-h for the processed ones.
ARTICLE | doi:10.20944/preprints202109.0092.v1
Subject: Behavioral Sciences, Behavioral Neuroscience Keywords: breath; respiration; synchronization; coupling,; EEG; theta-beta ratio; pranayama; meditation; attention; citta vritti
Online: 6 September 2021 (12:49:41 CEST)
Yogic and meditative traditions have long held that the fluctuations of the breath and the mind are intimately related. While respiratory modulation of cortical activity and attentional switching are established, the extent to which electrophysiological markers of attention exhibit synchronization with respiration is unknown. To this end, we examined 1) frontal midline theta-beta ratio, an indicator of attentional control state known to correlate with mind wandering episodes and functional connectivity of the executive control network; 2) pupil diameter (PD), a known proxy measure of locus coeruleus (LC) noradrenergic activity; and 3) respiration for evidence of phase synchronization and information transfer (multivariate Granger causality) during quiet restful breathing. Our results indicate that both TBR and PD are simultaneously synchronized with the breath, suggesting an underlying oscillation of an attentionally relevant electrophysiological index that is phase-locked to the respiratory cycle which could have the potential to bias the attentional system into switching states. We highlight the LC’s pivotal role as a coupling mechanism between respiration and TBR, and elaborate on its dual functions as both a chemosensitive respiratory nucleus and a pacemaker of the attentional system. We further suggest that an appreciation of the dynamics of this weakly coupled oscillatory system could help deepen our understanding of the traditional claim of a relationship between breathing and attention.
ARTICLE | doi:10.20944/preprints202105.0462.v1
Subject: Engineering, Automotive Engineering Keywords: Respiration topography; waterpipe; hookah; combustible cigarettes, wearable respiratory monitor; lung volume; inhalation topography
Online: 20 May 2021 (09:30:48 CEST)
Background: Limited research has been done to measure ambulatory respiratory behavior, in particular those associated with tobacco use, in the natural environment due to a lack of monitoring techniques. Respiratory topography parameters provide useful information for modelling particle deposition in the lung and assessing exposure risk and health effects associated with tobacco use. Commercially available Wearable Respiratory Monitors (WRM), such as the Hexoskin Smart Garment, have embedded sensors which measure chest motion and may be adapted for measuring ambulatory lung volume. Methods: Self-reported ‘everyday’ and ‘some days’ Hookah and Cigarette smokers were recruited for a 3-day natural environment observation study. Participants wore the Hexoskin shirt while using their preferred tobacco product. The shirt was calibrated on them prior to, during, and after the observation period. A novel method for calculating the calibration parameters is presented. Results: N=5 Hookah and N=3 Cigarette participants were enrolled. Calibration parameters were obtained and applied to the observed chest motion waveform from each participant to obtain their lung volume waveform. Respiratory topography parameters were derived from the lung volume waveform. Conclusion: The feasibility of using the Hexoskin for measuring ambulatory respiratory topography parameters in the natural environment is demonstrated..
REVIEW | doi:10.20944/preprints201911.0334.v1
Subject: Life Sciences, Other Keywords: ethylene; ripening; alternative oxidase; alternative respiration; post-harvest; phytohormone; system 2 ethylene; fruit
Online: 27 November 2019 (06:46:00 CET)
Climacteric fruits are characterized by a dramatic increase in autocatalytic ethylene production, which is accompanied by a spike in respiration, at the onset of ripening. The change in the mode of ethylene production from autoinhibitory to auto-stimulatory is known as the system 1 (S1) to system 2 (S2) transition. Existing physiological models explain the basic and overarching genetic, hormonal, and transcriptional regulatory mechanisms governing the S1 to S2 transition of climacteric fruit. However, the links between ethylene and respiration, the two main factors that characterize the respiratory climacteric, have been largely understudied at the molecular level. Results of recent studies indicate that the AOX respiratory pathway may play an important role in mediating cross talk between ethylene response, carbon metabolism, ATP production, and ROS signaling during climacteric ripening. New genomic, metabolic, and epigenetic information sheds light on the interconnectedness of ripening-associated metabolic pathways, necessitating expanding the current, ethylene-centric physiological models. Understanding points at which ripening responses can be manipulated may reveal key, speciesand cultivar-specific targets for regulation of ripening enabling superior strategies for reducing postharvest wastage.
ARTICLE | doi:10.20944/preprints202012.0253.v1
Subject: Earth Sciences, Atmospheric Science Keywords: Birch effect; carbon flux; ecosystem function; intraspecific variation; plant-soil interaction; soil respiration; tree ontogeny
Online: 10 December 2020 (11:52:21 CET)
Soil CO2 efflux (FCO2) plays a dominant role in the terrestrial carbon (C) cycle but interpreting constraints on local observations is impeded by challenges in disentangling belowground CO2 sources. Trees contribute most C to forest soils, so linking aboveground properties to FCO2 could open new avenues to study plant-soil feedbacks and facilitate scaling; furthermore, FCO2 responds dynamically to meteorological conditions, complicating predictions of total FCO2 and forest C balance. We tested for proximity effects of individual Acer saccharum Marsh. trees on FCO2, comparing FCO2 within 1 m of mature stems to background fluxes before and after an intense rainfall event. Wetting significantly increased background FCO2 (6.4±0.3 vs. 8.6±0.6 s.e. μmol CO2 m-2s-1), with a much larger enhancement near tree stems (6.3±0.3 vs. 10.8±0.4 μmol CO2 m-2s-1). FCO2 varied significantly among individual trees and post-rain values increased with tree diameter (with a slope of 0.058 μmol CO2 m-2s-1 cm-1). Post-wetting amplification of FCO2 (the ‘Birch effect’) in root zones often results from the improved mobility of labile carbohydrates and further metabolization of recalcitrant organic matter, which may both occur at higher densities near larger trees. Our results indicate that plant-soil feedbacks change through tree ontogeny and provide evidence for a novel link between whole-system carbon fluxes and forest structure.
ARTICLE | doi:10.20944/preprints201711.0196.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: carbohydrate starvation; non-structural carbohydrate; photosynthesis; photosynthesis inhibition; respiration; relative growth rate; structure; diurnal variation
Online: 30 November 2017 (08:48:58 CET)
Predicting the growth response of seedlings from the environmental responses of photosynthesis and metabolism may be improved by considering the dynamics of non-structural carbohydrate, NSC, over a diurnal cycle. Attenuation of growth metabolism when NSC content is low could explain why some NSC is conserved through the night. A dynamic model, incorporating diurnal variation in NSC, was developed to simulate growth of seedlings hour-by-hour. I compared predictions of this model to published growth and NSC data for seedlings that varied according to temperature, light, day length, or CO2. Prolonged-darkness experiments showed a temperature dependent upper limit on the respiration capacity. Respiration was attenuated as NSC was depleted. Furthermore, when NSC was high at dawn, inhibition of photosynthesis could attenuate the accumulation of NSC under low temperature, or high light, or high CO2. These concepts were used to simulate plant metabolism and growth rates and diurnal variation of NSC in tomato seedlings under two light levels and various temperatures. Comparison of other results using the same model parameters showed the dynamic model could predict results for starch and starch-less plants, and when growth was affected by CO2 enrichment and day length.
ARTICLE | doi:10.20944/preprints202208.0390.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Biosensing; Coronaviru; , SARS-CoV-2; COVID-19; Early diagnosis; Epidemic control; Respiration monitor; Photoacoustic imaging; Neurostimulation
Online: 23 August 2022 (03:44:42 CEST)
The recent COVID-19 pandemic has caused tremendous damage to social economy and people’s health. Some major issues fighting COVID-19 include early and accurate diagnosis and the shortage of ventilator machines for critical patients. In this work, we propose a closed-loop solution to deal with COVID-19: portable biosensing and wearable photoacoustic imaging for early and accurate diagnosis of infection and magnetically neuromodulation or minimally invasive electrical stimulation to replace the traditional ventilation. Proposed technique can guarantee ubiquitous and onsite detection, and electrical hypoglossal stimulator can be more effective in helping severe patients as well as reducing complications caused by ventilators.
ARTICLE | doi:10.20944/preprints202007.0677.v1
Subject: Biology, Agricultural Sciences & Agronomy Keywords: conservation agriculture; compost; soil quality; bio-test; macro- and micronutrients; free-living nematodes; microbial respiration; microbial biomass
Online: 28 July 2020 (10:31:47 CEST)
Reduced nutrient mineralization rates under minimum tillage are usually compensated by mineral fertilizer application. These cannot be applied in organic farming systems, however. We hypothesized that organic minimum tillage based on frequent cover cropping and application of dead mulch will improve soil fertility and can compensate for the potential negative effects of minimum tillage. Two long-term field experiments were set up in 2010 and 2011 comparing plough versus minimum tillage including application of transferred mulch. As second factor, the application of compost versus mineral potassium and phosphorus was compared. In 2019, soils were analyzed for soil pH, organic carbon, macro-, micronutrients, microbial biomass, microbial activity and total nematode abundance. In addition, performance of pea in the same soils was determined under greenhouse conditions. Across both experiments, macronutrients (+52%), micronutrients (+11%), microbial biomass (+51%), microbial activity (+86%), and bacterivorous nematodes (+112%) increased in minimum tillage compared with the plough-based system. In the greenhouse, pea biomass was 45% higher in the soil that had been subjected to minimum tillage compared to the plough. In conclusion, soil fertility can be improved in organic minimum tillage systems by intensive cover cropping and application of dead mulch to levels higher than in a plough-based system.
BRIEF REPORT | doi:10.20944/preprints202203.0104.v3
Subject: Biology, Plant Sciences Keywords: Calvin-Benson cycle; carbon metabolism; CO2 fertilisation; glucose-6-phosphate shunt; hydrogen stable isotopes; oxidative pentose phosphate pathway; photosynthesis; respiration
Online: 16 May 2022 (12:14:30 CEST)
Despite significant research efforts, the question of whether rising atmospheric CO2 concentrations (Ca) affect leaf respiration remains unanswered. Here, I reanalyse published hydrogen isotope abundances in starch glucose of sunflower leaves. I report that, as Ca increases from 450 to 1500 ppm, respiration by the oxidative pentose phosphate pathway in chloroplasts increases from 0 to ≈ 5% relative to net carbon assimilation. This is consistent with known regulatory properties of the pathway. Summarising recent reports of metabolic fluxes in plant leaves, a picture emerges in which mitochondrial processes are distinctly less important for overall respiration than the oxidative pentose phosphate pathways in chloroplasts and the cytosol. Regulatory properties of these pathways are consistent with observations of lower-than-expected stimulations of photosynthesis in response to increasing Ca. Reported advances in understanding leaf respiratory mechanisms may enable modelling and prediction of respiration effects (inter alia) on biosphere-atmosphere CO2 exchange and plant performance under climate change.
ARTICLE | doi:10.20944/preprints202102.0021.v1
Subject: Life Sciences, Biochemistry Keywords: excess winter mortality; influenza; latitude; gender; age; respiratory conditions; spatiotemporal effects; female; male; pandemics; seasons; ethnic groups; respiration disorders; coinfection
Online: 1 February 2021 (12:16:39 CET)
(1) Background: To investigate the dynamic issues behind international variation in EWM. (2) A rolling EWM calculation is used to reveal seasonal changes in the EWM calculation and is especially relevant nearer to the equator. (3) Results: In addition to latitude country specific factors determine EWM. Females generally show higher EWM mainly due to respiratory conditions. The EWM for respiratory conditions in England and Wales ranges from 44% to 83% which is about double the all-cause mortality equivalent. Age has a profound effect on EWM with a peak in puberty and then increasing EWM at old age. The gap between male and female EWM seems to act as a diagnostic tool reflecting the infectious/metrological mix in each winter. Additional difference due to ethnicity are also observed. An EWM equivalent calculation for sickness absence demonstrates how additional health-related variables can be linked to EWM. (4) Conclusions: EWM does not reach a peak at the same time each year, especially so in the tropics. Countries midway between the equator and the poles show highest EWM. Differences between the genders are highly significant and seem to vary according to the mix of variables active each winter. Pandemic influenza does not elevate EWM, although seasonal influenza plays a part each winter.
ARTICLE | doi:10.20944/preprints201608.0206.v2
Subject: Engineering, Electrical & Electronic Engineering Keywords: impulse radar; ultra-wideband (UWB); noncontact; short-range; healthcare; respiration; heartbeat; SNR; ensemble empirical mode decomposition (EEMD); continuous-wavelet transform (CWT)
Online: 15 September 2016 (11:24:00 CEST)
The radar sensor described realizes healthcare monitoring capable of detecting subject chest-wall movement caused by cardiopulmonary activities, and wirelessly estimating the respiration and heartbeat rates of the subject without attaching any devices to the body. No conventional Doppler only can capture Doppler signatures because of a lack of bandwidth information with noncontact sensors. In contrast, we take full advantages of impulse radio ultra-wideband (IR-UWB) radar to achieve low power consumption and convenient portability, with a flexible detection range and desirable accuracy. A noise reduction method based on improved ensemble empirical mode decomposition (EEMD) and a vital sign separation method based on continuous-wavelet transform (CWT) are proposed jointly to improve the signal-to-noise ratio (SNR) in order to acquire accurate respiration and heartbeat rates. This noncontact healthcare sensor system proves the commercial feasibility and considerable accessibility of using compact IR-UWB radar for emerging biomedical applications. Compared with traditional contact measurement devices, experimental results utilizing a 2.3 GHz bandwidth transceiver, demonstrate 100% similar results.