Physiological Causes Research Articles

Fetal cardiac troponin I levels decline toward birth in sheep.

Elevated cardiac troponin I (cTnI), a myocardial damage biomarker, has been reported in cord blood of neonates delivered vaginally or by cesarean section. Although the neonatal peak likely reflects the physiological adjustment to extrauterine life, a better understanding of serial prepartum changes is required to determine physiological causes of fetal cTnI release. We longitudinally sampled eight healthy lambs (20 days before spontaneous birth to 5 days postnatal), and from three fetuses receiving intravenous IGF-1. Samples were collected into heparin, and the plasma was stored at -80°C for later determination of high-sensitivity (hs) cTnI levels (BeckmanCoulter UniCel DxI Access IA; log transformed detection limit = 0.30, quantification limit = 0.78, 99th percentile = 1.78). Positive and negative control samples were drawn from an adult ewe during a terminal experiment (myocardial ischemia) and similarly assessed. hs-cTnI data were log transformed from ng/L. Log(hs-cTnI) was 1.47 ± 0.30 (means ± SD) at 20 days before birth and declined to 1.02 ± 0.65 in fetuses 12 ± 4 h before birth (P < 0.0001, R2 = 0.7869). Birth stimulated a delayed, transient peak in hs-cTnI (P = 0.0058). Newborn (43 ± 19 min postnatal) levels were 1.39 ± 0.40 (P = 0.0650 vs. fetus on day of birth) and 2.14 ± 0.63 the day after birth (P = 0.0331 vs. newborn). The second day after birth, levels declined to 1.65 ± 0.48 (P = 0.0238 vs. day 1). IGF-1 infusion increased hs-cTnI levels 25-50% over baseline (P = 0.0252, R2 = 0.9938). Baseline adult ewe log(hs-cTnI) was below the limit of detection; 3 h following coronary artery ligation, levels were 3.21. In conclusion, we newly report that fetal hs-cTnI levels decline concomitantly with reduced proliferation of cardiomyocytes toward term.NEW & NOTEWORTHY Serial blood samples were collected from catheterized, normally developing fetal and newborn lambs and high-sensitivity cardiac troponin I (hs-cTnI) levels were assessed, providing unprecedented insight into the physiological processes leading to high levels in the perinatal period. Moderately high levels of hs-cTnI found in the normally developing fetus declined toward term. An elevation to high levels peaked the day after birth, after which hs-cTnI declined again. Stimulation of fetal cardiomyocyte proliferation with IGF-1 also elevated hs-cTnI.

A prospective study on the causes of hyperbilirubinemia and its clinical markers in term and near-term newborns admitted to a tertiary care hospital in Patna, India

This study aimed to investigate the root causes, prognostic factors, and therapeutic strategies for neonatal hyperbilirubinemia among term and near-term infants admitted to the Neonatal Intensive Care Unit (NICU) at IGIMS, Patna. Furthermore, the research aimed to analyze the clinical progression of these infants throughout their NICU stay.Conducted within the NICU at IGIMS, Patna, Bihar, this study encompassed term and late preterm infants admitted with serum bilirubin levels exceeding 12 mg/dl. The primary focus was on identifying risk factors, etiological factors, and the clinical profile of these infants during their NICU tenure.The study examined birth weight distribution and concurrent medical conditions. Parameters included the initiation of phototherapy based on bilirubin levels and treatment methodologies. Out of the 210 infants studied, 27.14% and 47.62% weighed between 2001 and 2500 grams. The most prevalent causes were physiological (129 cases), fetal prematurity (30 cases), birth asphyxia (7 cases), and prolonged labor (18 cases). Idiopathic causes were observed in 28 instances, ABO incompatibility in 7 cases, and Rh incompatibility in 7 cases. G6PD deficiency was identified once. At the commencement of phototherapy, 19.52% had bilirubin levels between 12 and 15 mg/dl, 58.57% between 15.1 and 18 mg/dl, 11.91% above 20 mg/dl, and 10% between 18.1 and 20 mg/dl.Physiological causes emerged as the most frequent contributors to neonatal hyperbilirubinemia, followed by septicemia and idiopathic factors. Infrequent causes included blood group incompatibility. Phototherapy was established as a cost-effective and efficient method for reducing bilirubin levels in neonatal jaundice. Exchange transfusion proved to be a safe therapeutic measure in cases of severe hyperbilirubinemia. Blood group incompatibility was the main determinant requiring exchange transfusion.

The effect of biostimulants on parsnip seed germination and initial growth

Biostimulants are used for seed quality and performance improvement. However, the impact of biostimulants on parsnip seed quality has not been examined. Slow germination of parsnip is often further impeded by stress conditions. This study therefore aimed to assess whether treatments with different biostimulants could enhance seed germination and the initial seedling growth of parsnip. Amino acid and micronutrient-based biostimulants (0.2% solutions (v/v) of Technokel Amino Mix® and Megafol®) improved germination of parsnip seeds under optimal conditions, while biostimulant treatments with humic acid, fulvic acid and micronutrients (0.02% solution (v/v) of Organiko®) enhanced the initial growth. Our findings validate the potential of biostimulant application as a seed treatment. Determination of the main physiological causes of parsnip germination enhancement is needed in further research.

Age at natural menopause and its determinants in female population of Kharameh cohort study: Comparison of regression, conditional tree and forests.

Natural menopause is defined as the permanent cessation of menstruation that occurs after 12 consecutive months of amenorrhea without any obvious pathological or physiological cause. The age of this phenomenon has been reported to be associated with several health outcomes. This study aimed to estimate the Age at Natural Menopause (ANM) and to identify reproductive and demographic factors affecting ANM. This cross-sectional, population-based study was conducted on 2517 post-menopausal women aged 40-70 years participating in the first phase of the PERSIAN cohort study of Kharameh, Iran, during 2014-2017. To more accurately detect the determinants of ANM, we applied multiple linear regression beside some machine learning algorithms including conditional tree, conditional forest, and random forest. Then, the fitness of these methods was compared using Mean Squared Error (MSE) and Pearson correlation coefficient. The mean±SD of ANM was 48.95±6.13. Both applied forests provided more accurate results and identified more predictors. However, according to the final comparison, the conditional forest was the most accurate method which recognized that more pregnancies, longer breastfeeding, Fars ethnicity, and urbanization have the greatest impact on later ANM. This study found a wide range of reproductive and demographic factors affecting ANM. Considering our findings in decision-making can reduce the complications related to this phenomenon and, consequently, improve the quality of life of post-menopausal women.

(O-05) ESTRADIOL LEVELS IN MEXICAN MEN WITH ERECTILE DYSFUNCTION

Abstract Introduction and Objective Erectile dysfunction is associated with various psychological and physiological causes, including hormone levels such as testosterone. The role of estradiol in male sexual function is controversial, and studies reporting its impact on erectile function have been inconsistent. The aim of this study was to describe the levels of testosterone and estradiol in Mexican men with erectile dysfunction, based on the severity of dysfunction. Materials and Methods Hormonal levels of TSH, T3, T4, LH, FSH, total and free testosterone, and estradiol were measured in men over 18 years of age with erectile dysfunction, attending a clinic in Mexico. Clinical variables were analyzed, estimating measures of central tendency and dispersion for numerical variables, and absolute and relative frequencies for categorical variables. The proportion of men with abnormal levels of estradiol and testosterone was calculated based on the severity of erectile dysfunction. Results A total of 70 participants were included. The average age was 53.9 years old (+/- 11.8); 18.5% had severe dysfunction, 65.7% had moderate dysfunction, 14.2% had mild to moderate dysfunction, and 1.4% had mild dysfunction. 35.7% were diabetic, and 34.2% were hypertensive. 62.8% had abnormal levels in at least one of the evaluated hormones: 5.7% had low TSH levels; 2.8% had low T3 levels; 1.4% had low T4 levels; 5.7% had low and 7.1% had high total testosterone levels; 12.8% had low and 2.8% had high free testosterone levels; 17.1% had high prolactin levels; 1.4% had low and 10% had high LH levels; 5.7% had high FSH levels. Estradiol level was high in 6 men (8.5%), 1 had mild-moderate and 5 moderate dysfunction; 8 men had low estradiol levels (11.42%), 1 had mild-moderate, 4 moderate and 3 severe dysfunction. Conclusions Alteration on the levels of Estradiol was common in the analyzed group of patients with erectile dysfunction, especially in men with moderate dysfunction, observed in 12.8% of them. Financing Boston Medical Group.

The sensitivity of root water uptake to cold root temperature follows species-specific upper elevational distribution limits of temperate tree species.

Physiological water stress induced by low root temperatures might contribute to species-specific climatic limits of tree distribution. We investigated the low temperature sensitivity of root water uptake and transport in seedlings of 16 European tree species which reach their natural upper elevation distribution limits at different distances to the alpine treeline. We used 2H-H2O pulse-labelling to quantify the water uptake and transport velocity from roots to leaves in seedlings exposed to constant 15°C, 7°C or 2°C root temperature, but identical aboveground temperatures between 20°C and 25°C. In all species, low root temperatures reduced the water transport rate, accompanied by reduced stem water potentials and stomatal conductance. At 7°C root temperature, the relative water uptake rates among species correlated positively with the species-specific upper elevation limits, indicating an increasingly higher sensitivity to lower root zone temperatures, the lower a species'natural elevational distribution limit. Conversely, 2°C root temperature severely inhibited water uptake in all species, irrespective of the species'thermal elevational limits. We conclude that low temperature-induced hydraulic constraints contribute to the cold distribution limits of temperate tree species and are a potential physiological cause behind the low temperature limits of plant growth in general.

The difference in the world perception between a hysteric and a neurotic

The research significance is determined by the necessity to gain a more profound comprehension of the influence of mental disorders on an individual's perspective of the world. The research intends to conduct an empirical study to identify and compare the levels of personal indicators of world perception in individuals with hysterical and neurotic disorders. The methodology employed in investigating this issue involved surveying participants, which gathered data on the psychological condition and perception of the environment among the individuals involved in the study (n=62). The study employed various methods of scientific inquiry, including system analysis, comparison method, logical analysis, classification, synthesis, and deduction, in addition to conducting interviews with the respondents. It defines the terms “neurotic” and “hysteria”, describes the causes and consequences of an unstable emotional state, determines the connection between an unstable emotional state and neurotic and hysterical personality disorders, uncovers potential physiological causes for the development of these disorders, lists and describes physiological and sociocultural factors that shape a person's worldview, and explores personal factors that influence. The research materials possess practical significance as they provide empirical evidence of the impact of hysterical and neurotic personality disorders on an individual's perspective of the world.

Of Mice and Men: The Inter-individual Variability of the Brain's Response to Drugs.

Biological variation is ubiquitous in nature. Despite highly standardized breeding and husbandry under controlled environmental conditions, phenotypic diversity exists in laboratory mice and rats just as it does in humans. The resulting inter-individual variability affects various characteristics of animal disease models, including the responsiveness to drugs. Thus, the common practice of averaging data within an experimental group can lead to misinterpretations in neuroscience and other research fields. In this commentary, the impact of inter-individual variation in drug responsiveness is illustrated by examples from the testing of antiseizure medications in rodent temporal lobe epilepsy models. Individual mice and rats rendered epileptic by treatment according to standardized protocols fall into groups that either do or do not respond to antiseizure medications, thus mimicking the clinical situation in patients with epilepsy. Population responses are not normally distributed, and divergent responding is concealed in averages subjected to parametric statistical tests. Genetic, epigenetic, and environmental factors are believed to contribute to inter-individual variation in drug response but the specific molecular and physiological causes are not well understood. Being aware of inter-individual variability in rodents allows an improved interpretation of both behavioral phenotypes and drug effects in a pharmacological experiment.

Thermal optima in the hypoxia tolerance of marine ectotherms: Physiological causes and biogeographic consequences.

The minimum O2 needed to fuel the demand of aquatic animals is commonly observed to increase with temperature, driven by accelerating metabolism. However, recent measurements of critical O2 thresholds ("Pcrit") reveal more complex patterns, including those with a minimum at an intermediate thermal "optimum". To discern the prevalence, physiological drivers, and biogeographic manifestations of such curves, we analyze new experimental and biogeographic data using a general dynamic model of aquatic water breathers. The model simulates the transfer of oxygen from ambient water through a boundary layer and into animal tissues driven by temperature-dependent rates of metabolism, diffusive gas exchange, and ventilatory and circulatory systems with O2-protein binding. We find that a thermal optimum in Pcrit can arise even when all physiological rates increase steadily with temperature. This occurs when O2 supply at low temperatures is limited by a process that is more temperature sensitive than metabolism, but becomes limited by a less sensitive process at warmer temperatures. Analysis of published species respiratory traits suggests that this scenario is not uncommon in marine biota, with ventilation and circulation limiting supply under cold conditions and diffusion limiting supply at high temperatures. Using occurrence data, we show that species with these physiological traits inhabit lowest O2 waters near the optimal temperature for hypoxia tolerance and are restricted to higher O2 at temperatures above and below this optimum. Our results imply that hypoxia tolerance can decline under both cold and warm conditions and thus may influence both poleward and equatorward species range limits.

Are prolactin levels efficient in predicting a pituitary lesion in patients with hyperprolactinemia?

Data regarding the presence of a prolactin (PRL) threshold above which a pituitary magnetic resonance imaging (MRI) is mandatory in patients with hyperprolactinemia (hyperPRL) are controversial and derived primarily from studies focused on female populations. Aim of our study was to evaluate in a cohort of patients of both sexes with confirmed hyperPRL, the possible correlation between PRL values and the presence of pituitary abnormalities. We retrospectively analyzed data from patients who underwent serial PRL sampling at our Division between January 2015 and December 2022. Patients diagnosed with monomeric hyperPRL at serial sampling and with subsequent contrast-enhanced MRI results available for the pituitary region were included in the study. Exclusion criteria were prior pituitary disease, severe renal insufficiency, liver cirrhosis, uncompensated primary hypothyroidism and ongoing therapy with hyperprolactinemic drugs. Physiological causes of hyperPRL were also ruled out. Out of the 1253 patients who underwent serial PRL sampling, 139 patients (101 women and 38 men) met the inclusion criteria: 106 (76.3%) patients had some form of pituitary disease, with microlesions observed in 69.8%, macrolesions in 25.5% and other findings in 4.7% of subjects. PRL values showed a modest accuracy in predicting the presence of a pituitary abnormality and the best cut-offs identified were >25 µg/L (AUC 0.767, p = 0.003) and >44.2 µg/L (AUC 0.697, p < 0.001) in men and women, respectively; however, if only patients with PRL values > 500 µg/L were excluded from the analysis, as they were already supposed to harbor a macroprolactinoma, PRL levels were not able to predict the presence of a macrolesion neither in men nor women. Given the high prevalence of pituitary abnormalities in patients of both sexes with hyperPRL at serial sampling, performing a pituitary imaging in all cases of hyperPRL, even if mild, appears to be a cautious choice.

Ab. No. 20 “Pulse-Tech”- Ideation to Prototype to Measure Pulse Strength Device

Introduction: This study focused on the creation and evaluation of the ‘Pulse Tech’ device, a novel tool designed for the measurement of pulse strength. The pulse, a crucial indicator of cardiovascular health, reflects the heart’s efficacy in blood circulation. Traditional pulse assessment methods, while effective, often require significant expertise and could lack objectivity. The ‘Pulse Tech device addressed these limitations by offering a more standardized and accurate method for measuring pulse strength. Understanding pulse strength, including its rate, rhythm, and quality, is essential in diagnosing various cardiac conditions. The study delineated seven primary pulse points (temporal, carotid, brachial, femoral, radial, popliteal, dorsalis pedis) and their medical significance. It also detailed various cardiovascular pulse shapes, their physiological causes, and associated potential diseases. The ‘Pulse Tech device was innovatively designed to measure pulse strength objectively, utilizing advanced sensors and software for data capture and analysis. Its distinctive feature was the use of light absorption through blood vessels to indirectly measure pulse strength. The methodology comprised two phases: the first centered on designing and developing the device, including its components like the CPU section, pulse rate sensor, and software. The second phase involved testing the device on healthy individuals to validate its effectiveness against traditional methods. Methods: The study’s participant criteria included healthy individuals aged 18-30 years. The objective was to establish a new standard in pulse measurement, enhancing the accuracy and reliability of cardiovascular assessments. This was crucial in both clinical and research settings, potentially aiding in the early detection and management of heart-related diseases. The study emphasized the necessity of a ‘Pulse Tech’ in enabling physicians and physiotherapists to make more informed decisions about patient care. Conclusion: The ‘Pulse Tech’ device represented a significant advancement in biomedical devices, with the potential to revolutionize the measurement and interpretation of pulse strength in clinical practice.

Auditory model-based parameter estimation and selection of the most informative experimental conditions

Identifying the causes underlying a person’s hearing impairment is challenging. It requires linking the results of listening tests to possible pathologies of the highly non-linear auditory system. This process is further aggravated by restrictions in measurement time, especially in clinical settings. A central but difficult goal is thus, to maximize the diagnostic information that is collectable within a given time frame. This study demonstrates the practical applicability of the model-based experiment-steering procedure introduced in Herrmann and Dietz (2021, Acta Acustica, 5:51). The approach chooses the stimuli that are presented and estimates the model parameters best predicting the subject’s performance using a maximum-likelihood method. The same binaural tone-in-noise detection task was conducted using two measurement procedures: A standard adaptive staircase procedure and the model-based selection procedure based on an existing model. The model-steered procedure reached the same accuracy of model parameter estimation in on average only 42% of the time that was required with the standard adaptive procedure. Difficulties regarding the choice of a reliable model and reasonable discretization steps of its parameters are discussed. Although the physiological causes of an individual’s results cannot directly be inferred using this procedure, a characterization in terms of functional parameters is possible.

The physiological and pathological cause in the definition of the compensation for traumatic knee pathology: forensic medicine perspective

The physiological and pathological cause in the definition of the compensation for traumatic knee pathology: forensic medicine perspective

Hidden Effect of Baby Massage on Hyperbilirubinemia

Hyperbilirubinemia can occur when the level of bilirubin in the blood is more than 5 mg/dL, clinically characterized by the presence of jaundice with physiological and non-physiological causes. The main treatment for cases of hyperbilirubinemia today is phototherapy. However, in recent years there have been alternative interventions carried out, one of which is baby massage. The purpose of this paper is to analyze the effect of giving massage on the bilirubin levels of infants who have hyperbilirubinemia based on empirical studies of the last 10 years. The writing design uses a literature review with inclusion criteria according to the PICOS format. Methods to find sources or articles through the Pubmed, Proquest, Scient Direct, and Google Scholar databases (2016-2021) published in English and Indonesian. The keywords used are related to hyperbilirubinemia and baby massage. Based on the 10 articles reviewed, it was found that baby massage was given 1 to 3 times a day with a duration of 15-20 minutes in every session. Evaluation of bilirubin levels can use serum bilirubin levels or transcutaneous bilirubin levels, besides that giving massage also increases the frequency of defecation which plays a role in removing bilirubin from the baby's body. Baby massage is expected to prevent and treat standardized hyperbilirubinemia so that it can become uniform and as an alternative intervention in reducing bilirubin levels in infants

Evaluation of some hematological and biochemical parameters for women with polycystic ovary syndrome in Wasit Governorate

The aim of the study; the Study of physiological causes and risk factors of ovarian cysts in women and Analyzing the results statistically to determine the extent of the relationship between the physiological and biochemical causes of the occurrence of polycysticovaries. Polycystic ovary syndrome (PCOS) is one of the commonest endocrine disorders affecting many females in reproductive period which start from menarche till the menopause and commonly caused infertility around the world, and is characterized by irregular menstrual cycle, Hyperandrogensim and polycystic ovary; it can be considered a conditions involving reproductive, metabolic and cardiovascular components leading to lifelong health implication. Its prevalence among infertile women is between (15% to 20%). There is evidence that PCOS is a pro inflammatory disorder, characterized by the presence of low grade chronic inflammation that correlated with obesity or insulin resistance (IR). The purpose of this study is to investigate the role of study included 100 females diagnosed with PCOS, there were recruited from Al-kut hospital in Wasit during November 2022 until January 2023 , the diagnosis of polycystic ovary syndrome was based on the Rotterdam 2003 criteria. The control group consists of 50 fertile women who have regular menstrual cycle with no sign of hyperandrogenism and subjected to ultrasound examination and have normal hormonal levels. The age was identical in both groups and it was between (20-40) years. . Body mass index (BMI) for both patients and control group was calculated. The questionnaire form has been filled for each patient and control. Hormones levels luteinizing hormone (LH), follicle stimulating hormone (FSH), and thyroid stimulating hormone (TSH) were estimated. The present study was carried out in two parts: immunological and physiological study. ELISA technique has been used to determine the serum level of High –sensitivity C-reactive protin(Hscrp) . The results of Hscrp serum level was significantly increased (p&lt;0.oo5) in pcos patient(17.38+1.36) The results for physiological study demonstrated that insulin serum level recorded a highly significant difference (p &lt;0.05) in PCOS patients compared to control group, the mean level of this hormone for PCOS patients and control were (17.18±2.84) μIU/mL, (8.68±1.97) μIU/mL respective. While this study showed there were no significant differences in serum levels of T.protin, and TSH between PCOS patients (8.08± 1,28). ng/mL(, 0.79±0.17)μg/dL, and control group (7.09±0.51) ng/mL,( 1.20±0.09) μg/dL. This study illustrate that the serum levels of Hscrp and insulin were elevated in PCOS comparing to healthy women and this high levels related to PCOS independent on the presence of obesity or IR., and there was a positive correlation between the insulin hormone with the parameters Hscrp and this may be due to the background of PCOS which considered as inflammatory disease The reslts showed that ,Creatin ,cholesterol,GPT, and LDL ,Lympho ,TG were significantly increased in pcos patients than control group

Embryological observations on seed abortion in Hibiscus syriacus L. and physiological studies on nutrients, enzyme activity and endogenous hormones

Under natural conditions, most Hibiscus syriacus L. individuals form very few mature seeds or the mature seeds that do form are of poor quality. As a result, seed yield is poor and seeds have low natural germinability. These phenomena strongly hinder utilization of the excellent germplasm resources of H. syriacus. The study has shown that pollen activity and stigma receptivity were high on the day of anthesis, and the pistils and stamens were fertile. Pollen release and stigma receptivity were synchronous. But in styles following self and cross-pollination, pollen tube abnormalities (distortion and twisting of the pollen tubes) and callose deposition were observed. Cross-pollinated pollen tubes elongated faster and fewer pollen tube abnormalities were observed compared with self-pollinated pollen tubes. And during embryo development, abnormalities during the heart-shaped embryo stage led to embryo abortion. Imbalance in antioxidant enzyme activities and low contents of auxin and cytokinin during early stages of embryo development may affect embryo development. Therefore, a low frequency of outcrossing and mid-development embryo abortion may be important developmental causes of H. syriacus seed abortion. Nutrient deficiencies, imbalance in antioxidant enzyme activities, and a high content of abscisic acid at advanced stages of seed development may be physiological causes of seed abortion.

Management of Hyperprolactinemia in Clinical Practice

Background &amp; objectives: Hyperprolactinemia is defined as an increased prolactin level above the normal reference range, in women more than 25 ng/dl; with a prevalence rate of 10% in the general population. Hyperprolactinemia is associated with different clinical presentations various from oligomenorrhea, amenorrhea, galactorrhea, and infertility. This study aims to be to assess the current practice regarding the management of hyperprolactinemia in non-pregnant women in the Kurdistan region, Iraq. Subjects and Methods: An electronic questionnaire on current practice concerning diagnosis and treatment of hyperprolactinemia in non-pregnant women was sent through e-mail to 167 clinicians, 166 of them completed the survey and they were from different cities (Duhok, Sulaymaniyah, Erbil, and Halabja) of the Kurdistan region, Iraq. Results: A total of 166 valid questionnaires were collected. The response received from 166 clinicians. Almost 97 % of the responders were asking about the presence of symptoms of prolactinoma in patients with hyperprolactinemia and the majority of responders were made an exclusion of physiological causes related to hyperprolactinemia. When hyperprolactinemia occurred, only 81.3% of the respondents would test for thyroid-stimulating hormone routinely. Majority of the responders (79.5%) did not confirm the biochemical diagnosis of hyperprolactinemia before starting treatment and only two-thirds of them do pituitary imaging. Also, our results show an important role of clinician’s characteristics like age group on the management outcome, as the age group 25-35 was better when compared to the age group 46-55 (p-value =0.044) and the internist specialty and family medicine specialty have a better impact on management outcome in comparison to endocrinologist with (p-value =0.046 and 0.043 respectively). Conclusions: We found that the current clinical practice for the management of hyperprolactinemia is not uniform with some scientific defects. Therefore, it is necessary to develop national guidelines for the management and treatment of hyperprolactinemia.

Indication of Light Stress in Ficus elastica Using Hyperspectral Imaging

Hyperspectral imaging techniques are widely used to remotely assess the vegetation and physiological condition of plants. Usually, such studies are carried out without taking into account the light history of the objects (for example, direct sunlight or light scattered by clouds), including light-stress conditions (photoinhibition). In addition, strong photoinhibitory lighting itself can cause stress. Until now, it is unknown how light history influences the physiologically meaningful spectral indices of reflected light. In the present work, shifts in the spectral reflectance characteristics of Ficus elastica leaves caused by 10 h exposure to photoinhibitory white LED light, 200 μmol photons m−2 s−1 (light stress), and moderate natural light, 50 μmol photons m−2 s−1 (shade) are compared to dark-adapted plants. Measurements were performed with a Cubert UHD-185 hyperspectral camera in discrete spectral bands centred on wavelengths from 450 to 950 nm with a 4 nm step. It was shown that light stress leads to an increase in reflection in the range of 522–594 nm and a decrease in reflection at 666–682 nm. The physiological causes of the observed spectral shifts are discussed. Based on empirical data, the light-stress index (LSI) = mean(R666:682)/mean(R552:594) was calculated and tested. The data obtained suggest the possibility of identifying plant light stress using spectral sensors that remotely fix passive reflection with the need to take light history into account when analysing hyperspectral data.

Practical Aspects of Cardiopulmonary Exercise Testing in Children.

The use of cardiopulmonary exercise testing (CPET) in pediatrics provides critical insights into potential physiological causes of unexplained exercise-related complaints or symptoms, as well as specific pathophysiological patterns based on physiological responses or abnormalities. Furthermore, CPET helps evaluate exercise performance in children with chronic (lung/heart) diseases. For instance, it can ascertain any adverse reaction to exercise and estimate the effects of specific treatment measures. It affords a global assessment of the pathophysiological patterns, responses and abnormalities to exercise that is inadequately reflected by resting lung function and/or cardiac function assessment. Clinical interpretation of the results of a CPET in pediatrics requires specific knowledge regarding pathophysiological responses and interpretative strategies that can be adapted to address concerns specific to the child's medical condition or disability.

Yield response of maize hybrids with different ear flex to nitrogen rate and plant density

AbstractMaize (Zea mays L.) hybrids are frequently labeled as fixed or flex hybrid ear types by seed companies based on pre‐commercial trials or field observations during commercialization. However, the underlying physiological cause and the associated management with each hybrid ear type remains a question for growers. Experiments were conducted at multiple locations across 3 years to determine the yield and yield component response to combinations of plant density (4, 6, 8, 10, and 12 plant m−2) and nitrogen (N) rate (0, 78, 159, 235, and 314 kg N ha−1) for three fixed and four flex hybrid ear types. Optimal plant density (OPD) to reach maximum yield was 1.7 plant m−2 greater for fixed hybrid ear type compared to the flex hybrid ear type for N rates greater than 78 kg N ha−1. Flex hybrid ear type achieved similar yield at lower OPD through increased kernel weight (KW) without reduced kernels per square meter. Potential kernel number at silk appearance and established kernels 15 days after silk appearance were similar between hybrid ear types, indicating that the flex component was driven by KW. Fixed hybrid ear type displayed a lower threshold value of total aboveground biomass per plant at physiological maturity to set kernels compared to a flex hybrid ear type. Selection of a flex hybrid ear type provides opportunity for reduced planting density with similar yield potential and N management practices.