A conceptual model for changes in finger photoplethysmograph signals caused by hand posture and isothermic regulation

2022 ◽  
Author(s):  
Cameron Keogh ◽  
Gordon B Drummond ◽  
Andrew Bates ◽  
Janek Mann ◽  
DK Arvind
Keyword(s):  
Horizontal Plane ◽  
Current Knowledge ◽  
Red Light ◽  
Pulse Amplitude ◽  
Dominant Hand ◽  
Venous Circulation ◽  
Amplitude Increase ◽  
Waveform Amplitude ◽  
Finger Tip ◽  
Light Absorbance

Abstract Objective. To observe changes in baseline and pulsatile light absorbance (photoplethysmograph, PPG) in the finger-tip, by raising the hand above the horizontal plane in recumbent subjects. We applied current knowledge of the circulation to the finger-tip, particularly arteriovenous anastomoses (AVAs), and the physiology of the venous circulation. Approach. We studied healthy young volunteers in a quiet thermoneutral environment. A finger plethysmograph on the non-dominant hand recorded transmission of red and infra-red light, and the values were converted into absorbance to allow comparisons within and between subjects. Breathing movements were recorded unobtrusively to assess any effect on absorbance and the pulse amplitude of the signals. All body movements were passive: the study arm was elevated in a trough to about 40° above the horizontal plane. The following conditions were studied, each for 15 minutes, using the last 10 minutes for analysis: recumbent, study arm elevated, study arm horizontal, and both legs elevated by 40°. Main results. There was a substantial time-related effect, and considerable variation between subjects. Arm elevation reduced red light absorbance and increased the range of amplitudes of the PPG waveform: only in subjects with large absorbances, did waveform amplitude increase. The other main effect was that spontaneous, thermoregulatory decreases in absorbance were associated with decreases in waveform amplitude. Significance. Finger-tip vessels distend with blood when AVAs open. The vessels pulsate more strongly if venous collapse allows the vessels to become more compliant. The postcapillary circulation is likely to be an important source of pulsation.

scholarly journals Single Wavelengths of LED Light Supplement Promote the Biosynthesis of Major Cyclic Monoterpenes in Japanese Mint

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1420
Author(s):  
Takahiro Ueda ◽  
Miki Murata ◽  
Ken Yokawa
Keyword(s):  
Blue Light ◽  
Solid Phase ◽  
Glandular Trichomes ◽  
Red Light ◽  
Glandular Trichome ◽  
Pulse Amplitude ◽  
Light Treatment ◽  
Led Light ◽  
Trichome Formation ◽  
Japanese Mint

Environmental light conditions influence the biosynthesis of monoterpenes in the mint plant. Cyclic terpenes, such as menthol, menthone, pulegone, and menthofuran, are major odor components synthesized in mint leaves. However, it is unclear how light for cultivation affects the contents of these compounds. Artificial lighting using light-emitting diodes (LEDs) for plant cultivation has the advantage of preferential wavelength control. Here, we monitored monoterpene contents in hydroponically cultivated Japanese mint leaves under blue, red, or far-red wavelengths of LED light supplements. Volatile cyclic monoterpenes, pulegone, menthone, menthol, and menthofuran were quantified using the head-space solid phase microextraction method. As a result, all light wavelengths promoted the biosynthesis of the compounds. Remarkably, two weeks of blue-light supplement increased all compounds: pulegone (362% increase compared to the control), menthofuran (285%), menthone (223%), and menthol (389%). Red light slightly promoted pulegone (256%), menthofuran (178%), and menthol (197%). Interestingly, the accumulation of menthone (229%) or menthofuran (339%) was observed with far-red light treatment. The quantification of glandular trichomes density revealed that no increase under light supplement was confirmed. Blue light treatment even suppressed the glandular trichome formation. No promotion of photosynthesis was observed by pulse-amplitude-modulation (PAM) fluorometry. The present result indicates that light supplements directly promoted the biosynthetic pathways of cyclic monoterpenes.

scholarly journals Finger photoplethysmography during the Valsalva maneuver reflects left ventricular filling pressure

2012 ◽  
Vol 302 (10) ◽  
pp. H2043-H2047 ◽  
Author(s):  
Harry A. Silber ◽  
Jeffrey C. Trost ◽  
Peter V. Johnston ◽  
W. Lowell Maughan ◽  
Nae-Yuh Wang ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Amplitude Ratio ◽  
Valsalva Maneuver ◽  
Pulse Amplitude ◽  
Left Ventricular ◽  
Filling Pressure ◽  
Left Heart ◽  
Cardiac Filling Pressure ◽  
Cardiac Filling ◽  
Waveform Amplitude

It is often challenging to assess cardiac filling pressure clinically. An improved system for detecting or ruling out elevated cardiac filling pressure may help reduce hospitalizations for heart failure. The blood pressure response to the Valsalva maneuver reflects left heart filling pressure, but its underuse clinically may be due in part to lack of continuous blood pressure recording along with lack of standardization of expiratory effort. In this study, we tested whether Valsalva-induced changes in the pulse amplitude of finger photoplethysmography (PPG), a technology already widely available in medical settings, correlate with invasively measured left ventricular end-diastolic pressure (LVEDP). We tested 33 subjects before clinically scheduled cardiac catheterizations. A finger photoplethysmography waveform was recorded during a Valsalva effort of 20 mmHg expiratory pressure sustained for 10 s, an effort most patients can achieve. Pulse amplitude ratio (PAR) was calculated as the PPG waveform amplitude just before release of expiratory effort divided by the waveform amplitude at baseline. PAR was well correlated with LVEDP ( r = 0.68; P < 0.0001). For identifying LVEDP > 15 mmHG, PAR > 0.4 was 85% sensitive [95% confidence interval (95CI): 54–97%] and 80% specific (95CI: 56–93%). In conclusion, finger PPG, a technology already ubiquitous in medical centers, may be useful for assessing clinically meaningful categories of left heart filling pressure, using simple analysis of the waveform after a Valsalva maneuver effort that most patients can achieve.

scholarly journals Increased Ocular Pulse Amplitude Associated with Unilateral Dysgenesis of the Orbital Roof

2015 ◽  
Vol 6 (2) ◽  
pp. 158-163
Author(s):  
Ami Shah Vira ◽  
Ashraf M. Mahmoud ◽  
Cynthia J. Roberts ◽  
Steven E. Katz
Keyword(s):  
Pulse Amplitude ◽  
Neurofibromatosis Type ◽  
Contralateral Side ◽  
Dynamic Contour Tonometry ◽  
Ocular Pulse Amplitude ◽  
Orbital Roof ◽  
Intracranial Pressure Waveform ◽  
Waveform Amplitude ◽  
Ocular Pulse

Introduction: Two patients (one with neurofibromatosis type 1) presented with unilateral ocular pulsation. Methods: A CT scan of the orbits revealed extensive dysgenesis of the orbital roof with herniation of the frontal lobe into the orbit in both cases. PASCAL dynamic contour tonometry was performed. Results: The ipsilateral ocular pulse amplitude (OPA) was greater than the contralateral side, and the ocular pulse waveform morphology more closely approximated the known intracranial waveform in these patients. Conclusions: We hypothesize that the greater OPA was due to stronger transmission of the intracranial pressure waveform amplitude and morphology in the absence of the orbital roof.

scholarly journals Frequency distribution and mean comparisons of red light absorbance-transmittance of the e1 leaf sectors of five pipeline maize hybrids during early grain filling in subtropical winter

2015 ◽  
Author(s):  
Nav Raj Adhikari ◽  
Surya Kant Ghimire ◽  
Shrawan Kumar Sah ◽  
Keshab Babu Koirala
Keyword(s):  
Frequency Distribution ◽  
Flag Leaf ◽  
Red Light ◽  
Grain Filling ◽  
Fertility Level ◽  
Crop Species ◽  
Single Reading ◽  
Precision Evaluation ◽  
The Mean ◽  
Light Absorbance

Background: Crop scientist’s curiosities were to examine variation in photosynthetic sectors of grain filler leaf or flag leaf of any major crop species. Crop scientists including plant breeders too will be privileged from the findings. So it includes such precision evaluation of single cross pipeline hybrids of yellow maize before their release as cultivars. Materials and methods: For it, five pipeline hybrids were examined from two trials of RCBD trial that they were in a big research plot with uniform soil fertility level and with the same control environment. Each of the trials was conducted planting the seeds of the fifteen newly bred separate hybrids on October 3, 2012 exposing their flowering and early grain filling to the natural winter in the subtropical region in Nepal. Five plants of the pipeline hybrids of the fifteen plots of three replications were randomly selected and tagged from each of the fifteen plots of the five hybrids before tassel emergence. After about one month of anthesis, one hundred observations of red light absorbance-transmittance (RAT) measures were taken from chlorophyll meter ‘SPAD 502’ (Soil Plant Analysis Development) from the just-above-ear (e1) leaf of each of the selected plants of the hybrids in three days from 99 to 101 days after sowing (DAS). Results and discussion: From analysis of frequency distribution of the RAT SPAD measures of the e1 leaf sectors, it is not necessary that hybrids that demonstrates curve with high kurtosis always yield higher. Among the five hybrids, second highest grain yielding hybrid 112 had least leaf sectors of very low RAT SPAD measures. Besides, the hybrid 112 has been found least skewed and least peaked among the five hybrids. Furthermore, the hybrid 112 displayed least coefficient of variation and standard deviation among the 1500 RAT SPAD readings of its e1 leaf sectors. From the mean analysis through DMRT (Duncan Multiple Range Test), the twenty four averages have been found almost non-significant different among themselves inside each of the five hybrids. Single reading and four reading averages were non-significant different to one hundred reading average of each of the fifteen selected plants. Besides, the study also implies that a single reading from a leaf in the surrounding region of the topmost ear in five randomly selected plants can suffice to reflect the average SPAD measure of the particular leaf if the readings are from the e1 leaf. But, it can also be concluded that the similar non-significant nature of average central leaves around the top ear node. The mean comparison also gives useful information about the methodology of taking SPAD observations and how many readings are enough for the study of red light absorbance-transmittance, chl and N concentration in maize leaves. It also includes explanation why the e1 leaf is taken in the study.

scholarly journals Dynamics of chlorophyll and N concentration on e0 and e3 leaves of maize hybrids in winter in subtropical region

2015 ◽  
Author(s):  
Nav Raj Adhikari ◽  
Surya Kant Ghimire ◽  
Shrawan Kumar Sah ◽  
Keshab Babu Koirala
Keyword(s):  
Grain Yield ◽  
Soluble Protein ◽  
Red Light ◽  
Correlation Coefficients ◽  
Grain Filling ◽  
Soluble Proteins ◽  
Subtropical Region ◽  
Maize Breeding ◽  
Maize Hybrids ◽  
Light Absorbance

National maize productivity is very low in Nepal. To increase its productivity, hybrid maize breeding and their cultivation are indispensible. For it, fifteen newly bred single cross hybrids of yellow maize were examined to select superior high GYHs (grain yielding hybrids) from the standpoint grain yielding potentiality. In addition, dynamics of chl, N conc and red light absorbance-transmittance (RAT) have also examined from the standpoint of chl, N conc and RAT measure and their effects on grain yield (GY). For it, a trial of RCBD experiment was conducted in open field in winter in subtropical region in Nepal. Seeds were sown on October 3, 2012 plot in two row plot area of 1.4 x 3.0 m2. After anthesis, observations of chl and N conc implying RAT (red light absorbance-transmittance) SPAD (Soil Plant Analysis and Development) measures were taken from the topmost ear (e0 or E0) and third (e3 or E3) leaf above the e0 leaf in ten days interval during entire grain filling (GF). SPAD measures were transformed to total chl and N conc. E0 leaf has been found more grain yield determining than e3 leaf and terminal GF has been found more determining than early GF from the standpoint of correlation coefficients (r ) of GYs with chl, N conc and SPAD measure. From pooled variance analysis; SPAD and chl conc were not significant different in the two leaves and among the hybrids (Hybrids x Leaves x Ages). But, the SPAD and chl conc were significant different among the two leaves and ages (Leaves x Ages) irrespective of the hybrids. Different to the SPAD and chl conc, N conc was significant different in the leaves among the hybrids with respect to ages of the plants among the fifteen hybrids (Hybrids x Leaves x Ages). Thirteen top high GYHs 8, 12, 11, 13, 5, 6, 10, 1, 7, 14, 2, 9 and 15 were non-significant different from the standpoint of GY. The SPAD measures were in the non-significant range of 51-55 in e0 leaf in the duration from 95 to 125 d among the fifteen hybrids (FHs). Among the top four high GYHs 8, 12, 11 and 13; hybrid 11 lost chl and N from e0 leaf significantly on 135th d relative to the most of the hybrids. It means that the hybrid 11 could efficiently degrade N containing soluble protein and chl even on e0 leaf relatively. Top listed five high GYHs 8, 12, 11, 5 and 6 (except 13) constantly maintained chl and N conc implying SPAD on the e0 leaf up to the 135th d. In addition, it implies that these five hybrids sent newly up-taken N to kernels without degradation of the proteins and chl from the e0 leaf till the age of 135 d. High GYH 8 had degraded soluble proteins and enzymes and chl conc on e3 leaf and mobilized the degraded N to the kernels more efficiently from the e3 leaf. It is not necessary that maize hybrids must constantly maintain soluble proteins and chl conc during most of early to mid GF for high GY. Instead, diagnostic decline of the soluble protein and chl conc during early to mid GF also accelerate GF phenomena.

scholarly journals Dynamics of chlorophyll and N concentration on e0 and e3 leaves of maize hybrids in winter in subtropical region

2015 ◽  
Author(s):  
Nav Raj Adhikari ◽  
Surya Kant Ghimire ◽  
Shrawan Kumar Sah ◽  
Keshab Babu Koirala
Keyword(s):  
Grain Yield ◽  
Soluble Protein ◽  
Red Light ◽  
Correlation Coefficients ◽  
Grain Filling ◽  
Soluble Proteins ◽  
Subtropical Region ◽  
Maize Breeding ◽  
Maize Hybrids ◽  
Light Absorbance

National maize productivity is very low in Nepal. To increase its productivity, hybrid maize breeding and their cultivation are indispensible. For it, fifteen newly bred single cross hybrids of yellow maize were examined to select superior high GYHs (grain yielding hybrids) from the standpoint grain yielding potentiality. In addition, dynamics of chl, N conc and red light absorbance-transmittance (RAT) have also examined from the standpoint of chl, N conc and RAT measure and their effects on grain yield (GY). For it, a trial of RCBD experiment was conducted in open field in winter in subtropical region in Nepal. Seeds were sown on October 3, 2012 plot in two row plot area of 1.4 x 3.0 m2. After anthesis, observations of chl and N conc implying RAT (red light absorbance-transmittance) SPAD (Soil Plant Analysis and Development) measures were taken from the topmost ear (e0 or E0) and third (e3 or E3) leaf above the e0 leaf in ten days interval during entire grain filling (GF). SPAD measures were transformed to total chl and N conc. E0 leaf has been found more grain yield determining than e3 leaf and terminal GF has been found more determining than early GF from the standpoint of correlation coefficients (r ) of GYs with chl, N conc and SPAD measure. From pooled variance analysis; SPAD and chl conc were not significant different in the two leaves and among the hybrids (Hybrids x Leaves x Ages). But, the SPAD and chl conc were significant different among the two leaves and ages (Leaves x Ages) irrespective of the hybrids. Different to the SPAD and chl conc, N conc was significant different in the leaves among the hybrids with respect to ages of the plants among the fifteen hybrids (Hybrids x Leaves x Ages). Thirteen top high GYHs 8, 12, 11, 13, 5, 6, 10, 1, 7, 14, 2, 9 and 15 were non-significant different from the standpoint of GY. The SPAD measures were in the non-significant range of 51-55 in e0 leaf in the duration from 95 to 125 d among the fifteen hybrids (FHs). Among the top four high GYHs 8, 12, 11 and 13; hybrid 11 lost chl and N from e0 leaf significantly on 135th d relative to the most of the hybrids. It means that the hybrid 11 could efficiently degrade N containing soluble protein and chl even on e0 leaf relatively. Top listed five high GYHs 8, 12, 11, 5 and 6 (except 13) constantly maintained chl and N conc implying SPAD on the e0 leaf up to the 135th d. In addition, it implies that these five hybrids sent newly up-taken N to kernels without degradation of the proteins and chl from the e0 leaf till the age of 135 d. High GYH 8 had degraded soluble proteins and enzymes and chl conc on e3 leaf and mobilized the degraded N to the kernels more efficiently from the e3 leaf. It is not necessary that maize hybrids must constantly maintain soluble proteins and chl conc during most of early to mid GF for high GY. Instead, diagnostic decline of the soluble protein and chl conc during early to mid GF also accelerate GF phenomena.

The structural basis of far-red light absorbance by allophycocyanins

2020 ◽  
Vol 147 (1) ◽  
pp. 11-26
Author(s):  
Nathan Soulier ◽  
Donald A. Bryant
Keyword(s):  
Red Light ◽  
Structural Basis ◽  
Light Absorbance

scholarly journals Epidural Oscillating Cardiac-Gated Intracranial Implant Modulates Cerebral Blood Flow

Neurosurgery ◽  
2020 ◽  
Author(s):  
Mark G Luciano ◽  
Stephen M Dombrowski ◽  
Serge El-Khoury ◽  
Jun Yang ◽  
Suraj Thyagaraj ◽  
...  
Keyword(s):  
Heart Rate ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Balloon Catheter ◽  
Pulse Amplitude ◽  
Mean Values ◽  
Arterial Blood ◽  
Amplitude Increase ◽  
And Inversion ◽  
Change In Mean

Abstract Background We have previously reported a method and device capable of manipulating ICP pulsatility while minimally effecting mean ICP. Objective To test the hypothesis that different modulations of the intracranial pressure (ICP) pulse waveform will have a differential effect on cerebral blood flow (CBF). Methods Using an epidural balloon catheter attached to a cardiac-gated oscillating pump, 13 canine subjects underwent ICP waveform manipulation comparing different sequences of oscillation in successive animals. The epidural balloon was implanted unilaterally superior to the Sylvian sulcus. Subjects underwent ICP pulse augmentation, reduction and inversion protocols, directly comparing time segments of system activation and deactivation. ICP and CBF were measured bilaterally along with systemic pressure and heart rate. CBF was measured using both thermal diffusion, and laser doppler probes. Results The activation of the cardiac-gate balloon implant resulted in an ipsilateral/contralateral ICP pulse amplitude increase with augmentation (217%/202% respectively, P &lt; .0005) and inversion (139%/120%, P &lt; .0005). The observed changes associated with the ICP mean values were smaller, increasing with augmentation (23%/31%, P &lt; .0001) while decreasing with inversion (7%/11%, P = .006/.0003) and reduction (4%/5%, P &lt; .0005). CBF increase was observed for both inversion and reduction protocols (28%/7.4%, P &lt; .0001/P = .006 and 2.4%/1.3%, P &lt; .0001/P = .003), but not the augmentation protocol. The change in CBF was correlated with ICP pulse amplitude and systolic peak changes and not with change in mean ICP or systemic variables (heart rate, arterial blood pressure). Conclusion Cardiac-gated manipulation of ICP pulsatility allows the study of intracranial pulsatile dynamics and provides a potential means of altering CBF.

scholarly journals Light-Mediated Regulation of Leaf Senescence

2021 ◽  
Vol 22 (7) ◽  
pp. 3291
Author(s):  
Yasuhito Sakuraba
Keyword(s):  
Leaf Senescence ◽  
Molecular Mechanisms ◽  
Transcriptional Regulatory Network ◽  
Current Knowledge ◽  
Red Light ◽  
Nuclear Gene ◽  
Nuclear Gene Expression ◽  
Transcriptional Regulatory ◽  
Plant Life Cycle

Light is the primary regulator of various biological processes during the plant life cycle. Although plants utilize photosynthetically active radiation to generate chemical energy, they possess several photoreceptors that perceive light of specific wavelengths and then induce wavelength-specific responses. Light is also one of the key determinants of the initiation of leaf senescence, the last stage of leaf development. As the leaf photosynthetic activity decreases during the senescence phase, chloroplasts generate a variety of light-mediated retrograde signals to alter the expression of nuclear genes. On the other hand, phytochrome B (phyB)-mediated red-light signaling inhibits the initiation of leaf senescence by repressing the phytochrome interacting factor (PIF)-mediated transcriptional regulatory network involved in leaf senescence. In recent years, significant progress has been made in the field of leaf senescence to elucidate the role of light in the regulation of nuclear gene expression at the molecular level during the senescence phase. This review presents a summary of the current knowledge of the molecular mechanisms underlying light-mediated regulation of leaf senescence.

scholarly journals Frequency distribution and mean comparisons of red light absorbance-transmittance of the e1 leaf sectors of five pipeline maize hybrids during early grain filling in subtropical winter

2015 ◽  
Author(s):  
Nav Raj Adhikari ◽  
Surya Kant Ghimire ◽  
Shrawan Kumar Sah ◽  
Keshab Babu Koirala
Keyword(s):  
Frequency Distribution ◽  
Flag Leaf ◽  
Red Light ◽  
Grain Filling ◽  
Fertility Level ◽  
Crop Species ◽  
Chlorophyll Meter ◽  
Single Reading ◽  
The Mean ◽  
Light Absorbance

Background: Crop scientist’s curiosities were to examine variation in photosynthetic sectors of grain filler leaf or flag leaf of any major crop species. Crop scientists including plant breeders too will be privileged from the findings. So it includes such precision evaluation of five single cross pipeline hybrids (Hs 6, 112, 14, 113 and 109) of yellow maize using red light absorbance-transmittance (RAT) measure by chlorophyll meter SPAD 502 before their release as cultivars. Materials and methods: For it, five pipeline hybrids were examined from two RCBD trials that they were in a big research plot with uniform soil fertility level and with the same control environment. Each of the trials was conducted planting the seeds of the fifteen newly bred separate hybrids on October 3, 2012 exposing their flowering and early grain filling to the natural winter in the subtropical region in Nepal. Five plants of the pipeline hybrids of the fifteen plots of three replications were randomly selected and tagged before tassel emergence. After about one month of anthesis, one hundred observations of the RAT SPAD measures were taken from the chlorophyll meter from the just-above-ear (e1) leaf of each of the selected plants of the hybrids of 180 to 185 days of crop maturity in three days from 99 to 101 days after sowing (DAS). Results and discussion: From analysis of frequency distribution of the RAT SPAD measures of the e1 leaf sectors, it is not necessary that hybrids that demonstrates curve with high kurtosis and high RAT SPAD measures always yield higher. Among the five hybrids, second highest grain yielding hybrid 112 had least leaf sectors of very low RAT SPAD measures. Besides, the hybrid 112 has been found least skewed and least peaked among the five hybrids. Furthermore, the hybrid 112 displayed least coefficient of variation and standard deviation among the 1500 RAT SPAD readings of its e1 leaf sectors. From the mean analysis through DMRT (Duncan Multiple Range Test), the twenty four averages have been found almost non-significant different among themselves inside each of the five hybrids. Single reading and four reading averages were non-significant different to one hundred reading average of each of the fifteen selected plants. Besides, the study also implies that a single reading from a leaf in the surrounding region of the topmost ear in five randomly selected plants can suffice to reflect the average SPAD measure of the particular leaf if the readings are from the e1 leaf. But, it can also be concluded that the similar non-significant nature of average central leaves around the top ear node. The mean comparison also gives useful information about the methodology of taking SPAD observations and how many readings are enough for the study of RAT, chl and N concentration in maize leaves. The paper includes logic of taking e1 leaf for RAT SPAD observations in discussion section.

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