24-hour Variation Research Articles

Dynamics of the energy spectrum of solar-diural variations in the intensity of cosmic rays in 22–25 cycles of solar activity

Periodic 24-hour variations in the intensity of galactic cosmic rays, continuously observed by ground-based detectors, are called solar diurnal variations. The nature of these variations lies in the existence in the interplanetary medium of an anisotropic spatial distribution of galactic cosmic rays, which arises during the interaction of these particles with the heliosphere. It is believed that the physical factors responsible for the observed anisotropy of galactic cosmic rays are the processes of convection, diffusion and their drift. The combination of these factors determines the main parameters of solar diurnal variations, such as amplitude, phase and energy spectrum. To study the energy spectrum of solar-diurnal variations, we used measurement data from muon telescopes of the Yakutsk Cosmic Ray Spectrograph after A.I. Kuzmin and Nagoya stations (Japan). The research approach is based on the idea of the crossed telescope method, originally designed to take into account the temperature effect. Due to the difference in the receiving characteristics of the crossed northern and southern directions of the above muon telescopes, the intensity variations recorded by them are sensitive to changes in the energy spectrum of solar-diurnal variations. This property was used to assess the dynamics of the energy spectrum of solar-diurnal variations for 22–25 cycles of solar activity. Analysis of the data obtained showed that in the last minimum of solar activity in 2018-2021. An anomalously early phase of solar-diurnal variations was observed. To study this phenomenon, we simulated the ratio and phase difference of a pair of northern and southern crossed directions for both muon telescopes for different types and values of the energy spectrum of solar-diurnal variations. A comparison of model calculations and observational data has made it possible to establish that during periods of minimum solar activity in the positive polarity of the general magnetic field of the Sun, a significant softening of the energy spectrum of solar-diurnal variations is observed. The reasons for the discovered phenomenon are discussed.

Daily variation in blood glucose levels during continuous enteral nutrition in patients on the intensive care unit: a retrospective observational study

BackgroundThe circadian timing system coordinates daily cycles in physiological functions, including glucose metabolism and insulin sensitivity. Here, the aim was to characterise the 24-hour variation in glucose levels in critically ill patients during continuous enteral nutrition after controlling for potential sources of bias. MethodsTime-stamped clinical data from adult patients who stayed in the Intensive Care Unit (ICU) for at least 4 days and received enteral nutrition were extracted from the Medical Information Mart for Intensive Care (MIMIC)-IV database. Linear mixed-effects and XGBoost modelling were used to determine the effect of time of day on blood glucose values. FindingsIn total, 207,647 glucose measurements collected during enteral nutrition were available from 6,929 ICU patients (3,948 males and 2,981 females). Using linear mixed-effects modelling, time of day had a significant effect on blood glucose levels (p<0·001), with a peak of 9·6 [9·5 – 9·6; estimated marginal means, 95% CI] mmol/L at 10:00 in the morning and a trough of 8·6 [8·5 – 8·6] mmol/L at 02:00 at night. A similar impact of time of day on glucose levels was found with the XGBoost regression model. InterpretationThese results revealed marked 24-hour variation in glucose levels in ICU patients even during continuous enteral nutrition. This 24-hour pattern persists after adjustment for potential sources of bias, suggesting it may be the result of endogenous biological rhythmicity.Funding: This work was supported by a VENI grant (2020-09150161910128) from the Netherlands Organization for Health Research and Development (ZonMw), an institutional project grant, and by the Dutch Research Council (NWO).

Circadian rhythm in pro-arrhythmic activity of pulmonary vein cardiomyocytes

Abstract Introduction Cardiomyocytes in the pulmonary vein (PV) sleeves are a major source of ectopic activity driving atrial fibrillation (AF) and episodes of AF in patients are more prevalent at night. While it is known that circadian clocks within the heart regionally control 24-hour variation in pacemaking and ventricular repolarisation, the mechanisms underlying the nighttime preponderance in AF are unknown. Purpose This study addresses the hypothesis that circadian rhythms exist in the pro-arrhythmic activity of PV cardiomyocytes. Methods Male Wistar rats maintained in a 24-hour cycle of 12-hr light/dark (lights-on at Zeitgeber time, ZT=0; lights-off, ZT12) were subject to terminal general anaesthesia (140 mg/kg Na pentobarbital i.p.) at ZT=0, 6, 12 or 18 hr and the hearts removed. RNA was extracted from left atrial (LA) appendage (LAA) and proximal PV at the LA/PV junction (3 rats per ZT) and RNA sequencing conducted. Reads were mapped to the rat genome, counts normalised and models in which ZT was or was not included as a factor compared (Likelihood Ratio Test, adjusted-P&amp;lt;0.01). Whole-cell current clamp recordings were made from cardiomyocytes isolated from the proximal PV (n=308) and the LAA (n=264) (N=74 rats). The effects of noradrenaline (NA, 1 µM) and acetylcholine (ACh, 1 µM) were examined. Data were plotted against the ZT of the time of recording and fitted to a sine wave to establish circadian rhythmicity (P&amp;lt;0.05, extra-sum-of-squares F-test). The effect of ≥24 hr constant dark in the period immediately before experiment was examined. Data are reported as mean ± standard error. Results The expression of 1368 genes varied significantly with ZT, including circadian clock components (e.g. Bmal1, Per1). PV cells were larger than LAA cells (73±1.6 pF vs 53±1.3 pF, P&amp;lt;0.0001) and had more depolarised resting membrane potential (-69±0.2 mV vs -72±0.1 mV, P&amp;lt;0.0001). Both cell types showed circadian variation in action potential duration at 90% repolarisation (APD90) and frequency of pro-arrhythmic activity. Pro-arrhythmic activity was greatest in PV cells and the frequency was greater during the rest phase (ZT0-12) in both cell types. In contrast, the circadian rhythm in APD90 differed between cell type, with the longest APD­­90 recorded during the active phase in PV cells (ZT12-24) but during the rest phase in LAA cells. Pro-arrhythmic activity was increased by NA and decreased by ACh in both cell types with maximal effect during the rest phase. Conclusion Circadian variation in APD90 and proarrhythmic-activity has been demonstrated in isolated proximal PV and LAA cardiomyocytes, with differences in rhythm between the two cell types. RNA sequencing suggests the presence of peripheral clocks in LAA and PV cardiomyocytes. Understanding these mechanisms is important in development of future therapeutic options for AF.

Autonomous circadian rhythms in the human hepatocyte regulate hepatic drug metabolism and inflammatory responses.

Critical aspects of physiology and cell function exhibit self-sustained ~24-hour variations termed circadian rhythms. In the liver, circadian rhythms play fundamental roles in maintaining organ homeostasis. Here, we established and characterized an in vitro liver experimental system in which primary human hepatocytes display self-sustained oscillations. By generating gene expression profiles of these hepatocytes over time, we demonstrated that their transcriptional state is dynamic across 24 hours and identified a set of cycling genes with functions related to inflammation, drug metabolism, and energy homeostasis. We designed and tested a treatment protocol to minimize atorvastatin- and acetaminophen-induced hepatotoxicity. Last, we documented circadian-dependent induction of pro-inflammatory cytokines when triggered by LPS, IFN-β, or Plasmodium infection in human hepatocytes. Collectively, our findings emphasize that the phase of the circadian cycle has a robust impact on the efficacy and toxicity of drugs, and we provide a test bed to study the timing and magnitude of inflammatory responses over the course of infection in human liver.

Temporal pathways between circadian rhythm, depression and anxiety in the transition from adolescence to early adulthood

BackgroundSleep and circadian rhythm problems intertwine with affective disorders. Adolescents are particularly vulnerable to developing sleep and affective problems. Yet, the temporal pathways between circadian rhythm, depression and anxiety in the transition phase from adolescence to early adulthood are not fully understood. Methods233 adolescents (76 % females) participated at two time points (T1 and T2) at an interval of 19-months (aged 16.8 and 18.4 years). We used The Beck Depression Inventory-II, Generalized Anxiety Disorder Assessment, GENEActiv actigraphy across 8 days (delayed sleep phase (DSP), sleep duration, midpoint, and regularity), and iButton 1922L thermologgers across 3 days (intrinsic circadian period length, amplitude, and mesor). ResultsA shorter sleep duration at T1 associated with an increase in affective problems at T2, and affective problems at T1 associated with an increase in sleep irregularity at T2. A longer circadian period at T1 associated with an increase in males' affective problems at T2. Moderate to severe depression and anxiety at T1 associated with a 2.69-fold risk (95 % CI 1.38–5.26, p = 0.004) and 2.11-fold risk (95 % CI 1.04–4.25, p = 0.038) of poor sleep quality at T2. Moderate to severe generalized anxiety associated with a 3.17-fold risk (95 % CI 1.35–7.41, p = 0.008) of DSP at T2. LimitationsThe follow-up period is short. ConclusionsThe results revealed bidirectional temporal links between sleep and affective problems. Novel observations include a heightened risk of future DSP following a current anxiety disorder and a heightened risk of affective problems following a longer circadian period measured from the 24-hour temperature variation in males.

Twenty-Four-Hour Intraocular Pressure Pattern In Glaucoma Suspects in an African Population.

Twenty-four-hour intraocular pressure measurement (Phasing) among glaucoma suspects showed higher intraocular pressure (IOP), greater fluctuation, and more varying peak times occurring mostly outside clinic hours, between 12 midnight and 8 am in 68.9% of them. To characterise 24-hour variation in IOP, in glaucoma suspects and normal individuals in an African population. A cross-sectional analytical study was carried out between March and October 2019 at the University of Ilorin Teaching Hospital. A total of 204 study participants, comprising 102 primary open angle glaucoma (POAG) suspects and 102 age and sex-matched controls with healthy eyes were recruited. Participants had a comprehensive ophthalmic examination. Measurements of IOP were taken every 2 hours during a 24-hour period using an iCare tonometer. The mean age was 43.64±14.02 SD and 43.02±13.55 SD ( P =1.000) for POAG suspects and controls, respectively. The mean peak IOP was significantly higher in POAG suspects (21.87± 4.65mmHg) compared with controls (17.17± 2.32mmHg) ( P <0.001). Whereas, the mean trough IOP reading was not significantly different between the 2 groups. In both groups of participants, the peak and trough IOP in the majority were recorded outside of clinic hours. The majority (68.9%) of POAG suspects had a peak IOP between midnight and 8 am, whereas the control group peaked mostly at 4 pm (16.7%) and 4 am (41.7%). Twenty-four-hour IOP variation was 6mmHg or less in 73.6% of control eyes, while in the POAG suspects, 83.3% of eyes had variation greater than 6mmHg. Compared with age and sex-matched healthy controls, glaucoma suspects of African descent showed significantly higher mean IOP and IOP variation, with most peak IOP detected outside of clinic hours.

0295 Association between circadian rhythm of skin temperature and actigraphic sleep in free-living conditions: the HEIJO-KYO study

Abstract Introduction Skin temperature manipulation with little or no change in core body temperature affects sleep-wake states. However, the significance of 24-hour variation in skin temperature to sleep quality is unclear. We aimed to evaluate whether the circadian rhythm of distal skin temperature (DST) affects sleep quality in free-living conditions and to provide additional evidence about the relationship between thermal input to the skin and sleep-wake states. Methods In this cross-sectional study of 2,177 community-dwelling adults (Mean age 68.8 [SD 8.0] years), we measured DST using a temperature logger (Thermochron iButton, Maxim) at 3-minute intervals for seven consecutive days to calculate non-parametric indicators of circadian rhythm: intradaily variability (IV), interdaily stability (IS), and relative amplitude (RA). The participants underwent simultaneous 7-day wrist actigraphy (GT3X-BT, ActiGraph) to measure sleep objectively. The association between non-parametric indicators and 7-day means of sleep measures was evaluated using multivariable linear regression models. Results Lower quartiles of IV and higher quartiles of IS and RA were significantly associated with higher sleep efficiency, shorter wake after sleep onset, and longer total sleep time (all p &amp;lt;.001). After adjusting for potential confounders, including physical activity and outdoor temperature, the coefficients for the linear trend of sleep efficiency were −1.07 (95% confidence interval [CI]: −1.45, −0.69), 1.08 (95% CI: 0.75, 1.41), and 1.33 (95% CI: 0.83, 1.84) in IV, IS, and RA, respectively (all p &amp;lt;.001). Conclusion Circadian rhythms of DST with higher fluctuation, lower regularity across days, and blunted amplitude were associated with worse sleep quality. Our findings may be applied in thermoregulatory interventions to enhance sleep quality. Support (if any)

緑内障に対する眼圧下降治療の現状と限界

Currently, the only reliable treatment for glaucoma is intraocular pressure (IOP) -lowering therapy. Guidelines recommend setting a target IOP for each patient prior to starting treatment. Previous randomized controlled study results have shown that the lower the target IOP is set, the greater the suppression of glaucoma progression. In addition to lowering the mean clinical IOP, there also needs to be increased attention to IOP fluctuations, such as 24-hour and long-term IOP fluctuations. Although first-line drugs normally administered include prostanoid FP receptor agonists (FP agonists), EP2 receptor agonists (EP2 agonists), which do not lead to the periorbitopathy (PAP) associated with prostaglandin, are sometimes prescribed in Japan as first-line drugs. From an adherence viewpoint, the second-line drug is often changed to a fixed combination eye drop, with a fixed combination of an FP receptor agonist and a β-blocker. The IOP-lowering effects of glaucoma eye drops involve specific 24-hour variations that are dependent on the type of drug. While β-blockers have less nighttime IOP-lowering effects, FP agonists, the EP2 agonist, carbonic anhydrase inhibitors and ROCK inhibitors exhibit significant 24-h IOP-lowering effects. Unfortunately, even with multidrug therapy, the maximum 24-hour IOP tends to occur in the middle of the night. However, the use of selective laser trabeculoplasty and physiological outflow pathway reconstruction has been shown to not only reduce daytime IOP-lowering, but also nighttime IOP-lowering and 24-hour IOP fluctuations. In addition, trabeculectomy combined with mitomycin C has been shown to exhibit the greatest reduction in the preoperative mean IOP and 24-hour IOP fluctuation. Nevertheless, as the IOP is known to clinically increase postoperatively, multidrug therapy often needs to be restarted, thereby leading to increases in the 24-hour IOP fluctuations that will ultimately reduce the quality of the IOP-lowering effect.

Association between circadian skin temperature rhythms and actigraphic sleep measures in real-life settings.

Skin temperature manipulation with little or no change in core body temperature affects sleep-wake states; however, the association of 24-hour skin temperature variation with sleep quality has not been investigated in a large-scale population. We examined the association between the circadian rhythm of distal skin temperature and sleep quality in real-life settings and aimed to provide additional evidence of the link between thermoregulation and sleep-wake states. In this cross-sectional study of 2,187 community-dwelling adults, we measured distal skin temperature at the ventral forearm at 3-minute intervals for 7 consecutive days to calculate nonparametric indicators of a circadian skin temperature rhythm, including intradaily variability, interdaily stability, and relative amplitude. Participants underwent simultaneous 7-day wrist actigraphy to objectively measure sleep quality. The association between nonparametric circadian skin temperature rhythm indicators and 7-day sleep measures was evaluated using multivariable linear regression models. Lower intradaily variability and higher interdaily stability and relative amplitude of distal skin temperature were significantly associated with higher sleep efficiency, shorter wake after sleep onset, and longer total sleep time (all P < .001). After adjusting for demographic, clinical, and environmental factors, the coefficients for the linear trend of sleep efficiency were -1.20 (95% confidence interval: -1.53, -0.87), 1.08 (95% confidence interval: 0.80-1.36), and 1.47 (95% confidence interval: 1.04-1.89) per quartile increase in intradaily variability, interdaily stability, and relative amplitude, respectively (all P < .001). Distal skin temperature with lower fluctuations and higher regularity and rhythm amplitudes was associated with better sleep quality. Our results could be applied in chronobiological interventions to improve sleep quality. Tai Y, Obayashi K, Yamagami Y, Saeki K. Association between circadian skin temperature rhythms and actigraphic sleep measures in real-life settings. J Clin Sleep Med. 2023;19(7):1281-1292.

Hypertension Monitoring by a Real Time Management System for Patients in Community and Its Data Mining by Vector Autoregressive Model

Blood pressure has a 24-hour repetitive and regular variation which shows circadian rhythm. Using the multivariate time series analysis method of vector autoregressive model, we could realize the simultaneous prediction for both systolic and diastolic blood pressures. We choose blood pressure from 6 AM to 10 AM in 3 weeks as an episode to construct a prediction model. Missing values were imputed by regression models. Subsequently, we defined segments as positive or negative segments according to blood pressure measurements. The predictions were accomplished by vector autoregressive model (VAR). Both positive and negative segments were randomly selected from each patient to summarize the effect of prediction models. In this study, the MAPE (Mean Absolute Percentage Error) of systolic blood pressure and diastolic blood pressure were both less than 10%, indicating that the VAR model was adaptable in predicting the blood pressure of hypertensive patients. Based on VAR, we could provide early warning to breakthrough of blood pressure thresholds. The sensitivity, specificity, and accuracy for patients in the training sets were 77.50%, 81.58 %, and 79.49% respectively, and the sensitivity, specificity, and accuracy for patients in the training sets were 76.92%, 80.00% and 78.43% respectively. This research took information of both systolic and diastolic blood pressures at the same time to establish the VAR models and enabled simultaneous prediction for systolic and diastolic blood pressure.

LBSAT230 Daily Variation In Serum Calcifediol In Japanese And Non-japanese Adults

Abstract Circadian rhythm and 24-hour intra-subject variation in serum calcifediol (25-hydroxyvitamin D3) in the absence of vitamin D supplementation or treatment are poorly studied in healthy adults of any race. To address this dearth of information, a single-center, open-label study was completed in the US to evaluate both of these parameters in 67 male and female (balanced for gender) first generation Japanese (n=35) and non-Japanese (n=32) subjects, aged between 18 and 55 years. "First generation" was defined as: born in Japan; had 2 Japanese biological parents and 4 Japanese biological grandparents; had lived outside of Japan for less than 5 years; and, had made no significant changes in lifestyle, including diet, since leaving Japan. "Non-Japanese" was defined as: not of Japanese or Asian descent; and, parents and grandparents were not born in Japan or in any Asian countries. Enrolled subjects had a body mass index within 18. 0 to 30. 0 kg/m2 (inclusive) and body weight not less than 50 kg. The body weight for non-Japanese subjects was 9% to 17% higher than that of Japanese subjects (60.3 to 92.9 kg versus 51.2 to 84.9 kg). Exclusion criteria included consumption of a vitamin D supplement within the previous 28 days, consumption of grapefruit or oranges, alcohol, medications or tobacco within the previous 72 hours, and participation in strenuous physical activity within the previous 72 hours. Subjects were housed in a Phase 1 unit for 2 days where they received only standardized diets. Blood samples were collected on the second day at 0, 2, 4, 6, 8, 10, 12, 16 and 24 hours for determination of serum calcifediol by LC/MS/MS (mean accuracy: 0.37%; mean precision: 3. 07%) at Syneos Laboratories (Quebec, Canada). For all subjects, mean serum calcifediol levels ranged from 20.90 to 22.24 ng/mL over the 24-hour collection period with an average inter-subject variation (SD) of 6.79 ng/mL. A circadian rhythm was not evident either in the total population or in the racial subgroups. Mean intra-subject variation over 24 hours was 1. 08 ng/mL (SD; range: 0.27-3.22) or 5. 05% (CV; range: 2.36-14.81). Differences in 24-hour intra-subject variation between races were not significant (P&amp;gt;0. 05). These data support the conclusions that: (1) clinically meaningful circadian rhythms in serum calcifediol are absent in healthy first generation Japanese and non-Japanese adults living in the US; (2) the mean diurnal variation in serum calcifediol is small (approximately 5%); and (3) vitamin D therapies may appropriately be considered "physiological" if they raise serum total 25-hydroxyvitamin D after each dose only within the bounds of normal diurnal variation thereby allowing gradual adaptation to repletion. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

Unraveling water monitoring association towards weather attributes for response proportions data: A unit-Lindley learning.

Learning techniques involve unraveling regression structures, which aim to analyze in a probabilistic frame the associations across variables of interest. Thus, analyzing fraction and/or proportion data may not be adequate with standard regression procedures, since the linear regression models generally assume that the dependent (outcome) variable is normally distributed. In this manner, we propose a statistical model called unit-Lindley regression model, for the purpose of Statistical Process Control (SPC). As a result, a new control chart tool was proposed, which targets the water monitoring dynamic, as well as the monitoring of relative humidity, per minute, of Copiapó city, located in Atacama Desert (one of the driest non-polar places on Earth), north of Chile. Our results show that variables such as wind speed, 24-hour temperature variation, and solar radiation are useful to describe the amount of relative humidity in the air. Additionally, Information Visualization (InfoVis) tools help to understand the time seasonality of the water particle phenomenon of the region in near real-time analysis. The developed methodology also helps to label unusual events, such as Camanchaca, and other water monitoring-related events.

Patient Characteristics and Variables Influencing Acute Medical Flow.

Waiting times are the most widely used indicator of patient flow. This project aims to analyse 24-hour variation in referrals and waiting times for patients referred to the Acute Medical Service (AMS). A retrospective cohort study was conducted at the AMS of Wales' largest hospital. Collected data included patient characteristics, referral times, waiting times and adherence to Clinical Quality Indicators (CQIs). Peak referral times were found between 11:00-19:00. Peak waiting times occurred between 17:00-01:00, which was longer on weekdays in comparison to weekends. Referrals between 17:00-21:00 had the longest waiting times with > 40% of patients failing both junior and senior CQIs. Mean and median age and NEWS were higher between 17:00-09:00. Weekday evening and nights are problematic for acute medical patient flow. Interventions, including workforce, should be targeted towards these findings.

Occupational safety and health hazards in artisanal gold mines in western and Nyanza region, Kenya

Artisanal and small-scale gold mining (ASSGM) has experienced rapid growth due to mineral value and increasing poverty level in western and Nyanza regions in Kenya. The sub-sector has hazardous tasks occasioned by chemical exposures to such substances as mercury, physical strain and repetitive movements associated with extractive tasks challenge which vary from region to region and site to site. This paper reports findings of a study conducted on ASSGM in Kakamega (Roster mine and Ikolomani) and Migori (Masara-Suna West and Francis - Suna East) counties to assess workplace safety, health risk and good health practice among a population of one thousand four hundred (1400) miners and non-miners to identify and determine levels of health hazard in the sector. Descriptive cross-sectional design that involved stratified sampling technique with three broad stages was used: dividing mining and non-mining population in sub-groups (miners, foremen/supervisors, and head of households) at sites in administering to them research instrument using a simple random technique. Levels of airborne particulate matter (PM2.5 and PM10) were determined both at mining sites and away from mining sites using low cost monitor sensor (PA-11-SD Purple air sensor). The low-cost monitor sensor data was corrected using collocational data obtained using a continuous particulate monitor (BAM 1020) reference monitor in a similar location. SPSS version 25.0 was used to analyse qualitative data. The study found that common sources of hazards included handling elemental mercury with bare hands during amalgamation and exposure to fumes during refining raw sponge-like gold. Aaverage 24-hour variation cycle for (PM2.5 and PM10) was 117.11±14.47 and 195.18±15.35 μg/m3 in ambient air respectively at all mining sites. Histograms were used to present frequency distribution of variations for (PM2.5 and PM10) from mining activity. The average humidity and temperature variations of artisanal gold mining were in the range of (45-35) percentage (% RH) and (26-28)0C respectively. The study concluded that there were high risk cycle exposures to airborne particulate matter contaminants at artisanal gold mining sites as compared to non- mining sites. The study recommends that the county government should give priority to developing safe guidelines to ASSGM. The central government should also come up with guidelines on Occupational Safety and Health in artisanal gold mining to facilitate compliance with OSH requirements in the sector and offer effective participative training.

Durability of Residual Strength on Ac-Wc Mixture Using Bottom Ash As Fine Aggregate Substitution

Abstract. This study aims to determine the durability of the residual strength in the Asphalt Concrete – Wearing Course (AC-WC) mixture that uses bottom ash waste as a substitute for fine aggregate. The Marshall Test revealed that the stability value of all variations of the tested immersion met the minimum standard, which was greater than 800 kg, namely for the 0 hour immersion variation of 2170.75 kg, the 24-hour immersion variation of 2014, 62 kg, the immersion variation 48 hours of 1938.07 kg, variation of immersion 96 hours of 1853.45 kg, and the variation of immersion 168 hours of stability value obtained is 1747.68 kg. And for the residual strength index in the 24-hour immersion variation the residual stability index was obtained at 92.81%, for the 48-hour immersion variation the residual stability index was obtained at 89.33%, while for the 96-hour immersion variation the residual stability index was obtained at 85.38%. and for the variation of immersion 168 hours residual stability index was obtained at 80.51%, so that which meets the standard of at least 90% is the 24-hour variation.

Sol-Gel Synthesis and Characterization of Carbon doped TiO2 based on Solanum Tuberosum Starch

The carbon-doped TiO2 have been synthesized through sol-gel method using Solanum tuberosum starch as carbon source. The carbon precursor composition and reaction time were varied to study its influence to the crystal structure and electronic structure of resulted material. The C- TiO2 product was characterized by XRD, UV-Vis DRS, FTIR, and photocatalytic activity examine by methylene blue degradation. The results showed that variations in the composition of the carbon precursor and reaction time affected the characteristics of the crystal structure and photocatalyst activity of C- TiO2. The optimum variation was found in the variation of 1.5 gram carbon composition and 24 hours hydrolysis time which had the smallest particle size and lowest bandgap energy. The highest photocatalyst activity was obtained at a 24-hour reaction time variation with 59.375% percent of methylene blue degraded in the second-order reaction with a k value of 2.1351.

Open Radical Cystectomy versus Robot-Assisted Radical Cystectomy with Intracorporeal Urinary Diversion: Early Outcomes of a Single-Center Randomized Controlled Trial.

Radical cystectomy (RC) with urinary diversion (UD) is still considered a complex surgery associated with significant morbidity. Open RC (ORC) remains the reference option of treatment, even if adoption of robot-assisted RC (RARC) is rapidly increasing. To date, all the available randomized controlled trials were characterized by an extracorporeal approach in performing UD, undermining potential benefits of a totally minimally invasive procedure. In this study, we aimed to report perioperative and 6-month outcomes from the first RCT comparing ORC and RARC with totally intracorporeal UD. Patients were eligible for randomization if they had a diagnostic transurethral resection of bladder tumor with cT2-4, cN0, cM0 or recurrent high-grade nonmuscle-invasive bladder cancer and no anesthesiological contraindications to robotic surgery. Patients were enrolled with a covariate adaptive randomization process based on the following variables: body mass index, American Society of Anesthesiologists® score, baseline hemoglobin, planned UD, neoadjuvant chemotherapy and cT stage. The primary end point was to demonstrate the superiority of RARC with intracorporeal UD in terms of a 50% transfusion rate reduction. Overall, 116 consecutive patients (58 RARC, 58 ORC) were enrolled. Among primary endpoint, overall perioperative transfusion rates were significantly lower in the RARC cohort (RARC: 22% vs ORC: 41%; p=0.046). This prospective randomized trial observed 22% and 41% overall perioperative transfusion rates in patients treated by RARC and ORC, respectively, confirming a significant benefit in favor of RARC with intracorporeal UD. However, perioperative complications, hospital stay and 6-month health-related quality of life were largely comparable between groups. Oncologic and functional outcomes will be assessed at longer followup to observe potential differences between arms.

Multiparametric optimization of a reheated organic Rankine cycle for waste heat recovery based repowering of a degraded combined cycle gas turbine power plant

The study has conducted multiparametric optimization of a newly modified double stage reheated organic Rankine cycle configuration for the objective function of specific work output and its comparison with other conventional configurations of the organic Rankine cycle for the waste heat recovery-based repowering of a degraded combined cycle gas turbine power plant using R245fa, R113, and R141b as the working fluids. Thermodynamic performance of the triple cycle formed by integrating each organic Rankine cycle configuration with the combined cycle gas turbine unit is assessed in terms of repowering, specific fuel consumption and specific water consumption along with the associated greenhouse gas emissions. 24-hour performance variation of the combined cycle gas turbine unit has been incorporated in the analysis. It is found that the double stage reheated organic Rankine cycle configuration has outperformed other configurations in terms of thermodynamic performance. Triple cycle for the double stage reheated organic Rankine cycle has resulted in an average of 1.37% increase in net power output for the working fluid R141b, equivalent to 5.10 MW of additional power output. The thermal efficiency of the triple cycle for double stage reheated organic Rankine cycle has increased by 1.40%, whereas the specific fuel consumption and specific water consumption have reduced by 1.28% and 3.35%, respectively using R141b as the working fluid. The highest waste heat recovery potential is exhibited by the integrated basic organic Rankine cycle configuration for the working fluid R245fa, recovering 30,840 kW of waste heat, equivalent to the burning of 2467.2 kg/hr of CH4 and 6784.7 kg/hr CO2 emissions.

Resilient Microgrid Scheduling With Secure Frequency and Voltage Transient Response

The resilient operation of microgrids (MGs) relies strongly on their ability to operate in islanded mode, autonomously from the bulk grid, whilst adhering to secure operation requirements. Catastrophic events in the transmission grid can lead to abrupt MG islanding accommodated by large frequency and voltage excursions due to power imbalances within the MG. It is vital that MG scheduling algorithms incorporate both static and transient security metrics to ensure a secure transition during islanding, immunised against the transient phenomena. In this paper, we incorporate both frequency- and voltage-related security constraints in a MG operational planning problem to ensure robust operation against abrupt islanding events. We employ an iterative dynamic optimization approach, based on the sensitivities of active and reactive power injections to the system security metrics, to incorporate the transient and static security constraints in the planning problem. Due to their non-linear and intractable nature, the transient security constraints are reformulated as linear sequential resilience cuts resulting in a computationally efficient problem. The performance of the algorithm is shown on a 30-bus, 20 kV, distribution network, subject to a 24-hour variation in load and renewable generation.

Multiparametric optimization for reduced condenser cooling water consumption in a degraded combined cycle gas turbine power plant from a water-energy nexus perspective

The Water-Energy Nexus is gaining considerable interest with growing environmental concerns, especially in developing countries such as Pakistan that are now under a state of water stress. Thermal power plants consume large amounts of freshwater, thereby making their water usage optimization immensely important. For potential repowering featuring reduced cooling water consumption, a clear understanding of the influence of key condenser parameters on the power plant is required. This study investigates a degraded combined cycle gas turbine power plant for reduced cooling water usage from a repowering perspective. The degraded power plant under consideration draws 13% more freshwater for recirculation-based cooling from a canal linked with the River Indus in Pakistan. The power plant has been modeled using 120 h of real-time probabilistic data at baseload by generating three study cases stemming from 24-hour parametric variations. The commercial tool Cycle-Tempo has been deployed for modeling and simulating the power plant performance with the incorporation of physical uncertainties and errors originating from the measurement sensors. The model is validated and compared with the 23 years old design case data to highlight the degradations via an exergy analysis. A tri-parametric optimization is later performed to reduce the cooling water consumption through specialized performance maps that relate exergy, low-pressure section steam turbine performance, and condenser performance to highlight potential repowering opportunities while retaining the baseload performance. The optimized cases result in approximately 9.5–11.0% lesser water consumption in terms of mass flow rate while retaining the baseload performance and key heat recovery steam generator operating points.