A Robust Fractional-Order PID Controller Based Load Frequency Control Using Modified Hunger Games Search Optimizer

In this article, a recent modified meta-heuristic optimizer named the modified hunger games search optimizer (MHGS) is developed to determine the optimal parameters of a fractional-order proportional integral derivative (FOPID) based load frequency controller (LFC). As an interconnected system’s operation requires maintaining the tie-line power and frequency at their described values without permitting deviations in them, an enhanced optimizer is developed to identify the controllers’ parameters efficiently and rapidly. Therefore, the non-uniform mutation operator is proposed to strengthen the diversity of the solutions and discover the search landscape of the basic hunger games search optimizer (HGS), aiming to provide a reliable approach. The considered fitness function is the integral time absolute error (ITAE) comprising the deviations in tie-line power and frequencies. The analysis is implemented in two networks: the 1st network comprises a photovoltaic (PV) plant connected to the thermal plant, and the 2nd network has four connected plants, which are PV, wind turbine (WT), and 2 thermal units with generation rate constraints and governor dead-band. Two different load disturbances are imposed for two studied systems: static and dynamic. The results of the proposed approach of MHGS are compared with the marine predators algorithm (MPA), artificial ecosystem based optimization (AEO), equilibrium optimizer (EO), and Runge–Kutta based optimizer (RUN), as well as movable damped wave algorithm (DMV) results. Moreover, the performance specifications of the time responses of frequencies and tie-line powers’ violations comprising rise time, settling time, minimum/maximum setting values, overshoot, undershoot, and the peak level besides its duration are calculated. The proposed MHGS shows its reliability in providing the most efficient values for the FOPID controllers’ parameters that achieve the lowest fitness of 0.89726 in a rapid decaying. Moreover, the MHGS based system becomes stable the most quickly as it has the shortest settling time and is well constructed as it has the smallest peak, overshoots at early times, and then the system becomes steady. The results confirmed the competence of the proposed MHGS in designing efficient FOPID-LFC controllers that guarantee reliable operation in case of load disturbances.

Past rainfall and trace element variations in a tropical speleothem from India

An actively growing stalagmite (cave deposit) was collected in 1996 from the Dandak cave in Madhya Pradesh. Trace elements Mg, Sr and Ba were measured in order to asses their palaeoclimatic significance. More than 100% variations in the concentrations of trace elements have been observed during the growth period. The chemical and physical properties of the trace elements along with the data of stable isotope ratios of exygen and carbon from our earlier work has been discussed in this paper. Ratio of Ba to Sr concentrations has remained constant suggesting that the soil layers and bedrock dissolution have contributed the same proporation of trace elements to the cave seepage water. Slowly varying components in the Mg, Sr and Ba concentrations and profiles show high degrees of correlations. It is found that changes in the trace elements are mainly driven by the varying intensity of past rainfall. Trace element variations of speleothems in tropical regions can be used as indicators of the past rainfall intensities. Different climatic intervals are characterised based on trace elements and stable isotoes. Period 3700 to 3350 yr BP was found to be arid. High rainfall was observed between 3350 to 3200 yr BP. After a hiatus period of 2000 yr due to non-climate dependent proceses, again a high rainfall phase between 1200 to 400 yr BP was observed with a peak level at ~200 yr BP and a short arid phase at ~90 yr BP was also observed.

COVID-19 endgame: from pandemic to endemic? Vaccination, reopening and evolution in a well-vaccinated population

COVID-19 remains a major public health concern, with large resurgences even where there has been widespread uptake of vaccines. Waning immunity and the emergence of new variants will shape the long-term burden and dynamics of COVID-19. We explore the transition to the endemic state, and the endemic incidence, using a combination of modelling approaches. We compare gradual and rapid reopening and reopening at different vaccination levels. We examine how the eventual endemic state depends on the duration of immunity, the rate of importations, the efficacy of vaccines and the transmissibility. These depend on the evolution of the virus, which continues to undergo selection. Slower reopening leads to a lower peak level of incidence and fewer overall infections: as much as a 60% lower peak and a 10% lower total in some illustrative simulations; under realistic parameters, reopening when 70% of the population is vaccinated leads to a large resurgence in cases. The long-term endemic behaviour may stabilize as late as January 2023, with further waves of high incidence occurring depending on the transmissibility of the prevalent variant, duration of immunity, and antigenic drift. We find that long term endemic levels are not necessarily lower than current pandemic levels: in a population of 100,000 with representative parameter settings (Reproduction number 5, 1-year duration of immunity, vaccine efficacy at 80% and importations at 3 cases per 100K per day) there are over 100 daily incident cases in the model. The consequent burden on health care systems depends on the severity of infection in immunized or previously infected individuals.

The challenge of limited vaccine supplies: impact of prior infection on anti-spike IgG antibody trajectories after a single COVID-19 vaccination

Given high SARS-CoV-2 incidence, coupled with slow and inequitable vaccine roll-out, there is an urgent need for evidence to underpin optimum vaccine deployment, aiming to maximise global population immunity at speed. We evaluate whether a single vaccination in previously infected individuals generates similar initial and subsequent antibody responses to two vaccinations in those without prior infection. We compared anti-spike IgG antibody responses after a single dose of ChAdOx1, BNT162b2, or mRNA-1273 SARS-CoV-2 vaccines in the COVID-19 Infection Survey in the UK general population. In 100,849 adults who received at least one vaccination, 13,404 (13.3%) had serological and/or PCR evidence of prior infection. Prior infection significantly boosted antibody responses for all three vaccines, producing a higher peak level and longer half-life, and a response comparable to those without prior infection receiving two vaccinations. In those with prior infection, median time above the positivity threshold was estimated to last for >1 year after the first dose. Single-dose vaccination targeted to those previously infected may provide protection in populations with high rates of previous infection faced with limited vaccine supply, as an interim measure while vaccine campaigns are scaled up.

Comparative study of human growth hormone measurements: impact on clinical interpretation

Objectives Human growth hormone (hGH) provocation test is an essential tool to assess growth hormone deficiency (GHD) in children and young adults. It is important to have a robust method to determine the hGH peak of stimulation. This work aimed to compare three common automated immunoassays for hGH quantification and to ascertain whether there are still result-related differences which can impact clinical decision. Methods We analyzed the GH provocation test for 39 young subjects from pediatric department of Montpellier hospital, admitted for suspicion of growth hormone deficiency. The full range of measurements as well as the peak level of serum GH were compared using three automated immunoassays on three different immunoanalyzers: IDS-hGH on iSYS, LIAISON-hGH on Liaison XL and Elecsys ROCHE-hGH, on COBAS 8000. Results A good correlation was obtained between methods for all measurements (r 2>0.99) by using Passing–Bablok regression analysis. Bland–Altman analysis showed the best agreement between IDS-hGH and LIAISON-hGH systems (bias=−14.5%) compared to Elecsys ROCHE-hGH (bias=28.3%). When considering stratification of the study population and a unique cutoff, there were some discrepancies in interpretation of the results especially concerning the more recent Elecsys ROCHE-hGH assay. Nevertheless, when the adequate cutoff for each method was taken into account results were well correlated for all systems. Conclusions A cutoff for Elecsys Roche-hGH method was established to better explain the results. Clinician must be aware of the use of assay-specific cutoff to correctly integrate the results of GH tests in the GHD diagnosis.

236 Variation in cardiac troponin I serum levels after ECG exercise stress test in patients with microvascular angina

Aims Cardiac troponin I (cTnI) is considered a marker of myocardial necrosis. However, several studies have shown that cTnI increases also after short episodes of myocardial ischaemia. Nevertheless, it is unknown whether the changes in cTnI show differences according to the cause of myocardial ischaemia. Thus, our study aimed to evaluate cTnI response to ischaemia in patients with stable coronary artery disease (CAD), patients with microvascular angina (MVA), and transient ischaemia induced during percutaneous coronary intervention (PCI). Methods and results We studied four groups of patients: (1) patients with stable angina and obstructive CAD (coronary stenosis ≥50% and/or fractional flow reserve <0.80) (Group 1, n = 8); (2) patients with stable angina but no obstructive CAD and a final diagnosis of MVA according to positive intracoronary acetylcholine provocation test and/or coronary flow velocity reserve assessment with transthoracic Doppler echocardiography (Group 2, n = 20); (3) patients with stable angina and obstructive CAD undergoing PCI (Group 3, n = 10); (4) a control group of healthy subjects, with no history of cardiovascular disease (CVD) (Group 4, n = 20). Patients in groups 1, 2, and 4 underwent ECG exercise stress test (EST) according to a standard treadmill Bruce protocol. Peripheral venous blood samples were collected immediately before, at the end and 1, 3, and 24 h after test ending. Patients in group 3 underwent PCI with at least one drug-eluting stent implantation. Peripheral venous blood samples were collected immediately before, at the end and 1, 3, and 24 h after PCI ending. High-sensitivity cTnI (hs-cTnI) levels were measured by chemiluminescent microparticle immunoassay (CMIA). The main results of hs-cTnI in the four groups of patients are summarized in the table. Basal hs-cTnI serum levels were significantly higher in group 3, while there were no significant differences among groups 1, 2, and 4. Hs-cTnI serum levels significantly increased in all groups in response to the procedure (EST or PCI). A greater increase of hs-cTnI was found in group 3 (peak level at 24 h) compared to the other groups (peak level at 3 h). Furthermore, among patients undergoing EST, a significantly higher hs-cTnI increase was found in healthy subjects, compared to patients with CAD and MVA. Heart rate (HR) during stress test (both as an absolute value and predicted maximal HR for age) was the only variable statistically predictive of hs-cTnI increase during EST (HRmax: r 0.289, P 0.04; %HRmax: r 0.307; P 0.03). On the other hand, no clinical and laboratory variable was associated to hs-cTnI response after PCI. Conclusions Hs-cTnI serum levels increase after EST, both in patients with obstructive CAD and coronary microvascular dysfunction (CMD), but a similar increase is also observed in healthy subjects. More consistent hs-cTnI level increase with later peak-level is observed in patients with obstructive CAD after transient ischaemia induced during PCI.

Comparision of dexmedetomidine and clonidine with hyperbaric bupivacain in spinal anaesthesia

Background: Alpha-2 adrenergic agonists used as adjuvant to spinal anaesthesia produce substantial sensory and motor blockade of bupivacaine. This study was planned to compare the sensory and motor blockade characteristics of intrathecal combinations of adjuvants dexmedetomidine and clonidine with hyperbaric bupivacaine in the cases who underwent lower limb surgery under spinal anaesthesia.Methods: This was prospective, randomized, double blind study. 90 patients of age group between 18-60 years, ASA grade I and II were allotted into 3 equal groups. Group B received 15 mg bupivacaine plain, group BD and BC received dexmedetomidine (5mcg) and clonidine (50mcg) as adjuvants to bupivacaine respectively.Results: The duration of 2 dermatome regression time, sensory blockade and motor blockade were longest in dexmedetomidine group (129.37±4.87; 386±58.43; 353±48.87) in compared to clonidine (109.77±5.95; 296.53±57.19; 269.7±51.2) and bupivacaine group (81.03±6.83; 211.1± 30.47;181.03±20.8). Both drugs do not affect the peak level of sensory blockade, sensory block onset and motor block onset time. Dexmedetomidine and clonidine do not cause sedation in intraoperative and postoperative period.Conclusions: We conclude that addition of dexmedetomidine and clonidine in spinal anesthesia with hyperbaric bupivacaine increase the duration of ‘2 dermatome regression’ time, sensory and motor blockade and both are more with dexmedetomidine than with clonidine.

Reduced Regional Cerebral Blood Flow Measured by 99mTc-Hexamethyl Propylene Amine Oxime Single-Photon Emission Computed Tomography in Microgravity Simulated by 5-Day Dry Immersion

Microgravity induces a cephalad fluid shift that is responsible for cephalic venous stasis that may increase intracranial pressure (ICP) in astronauts. However, the effects of microgravity on regional cerebral blood flow (rCBF) are not known. We therefore investigated changes in rCBF in a 5-day dry immersion (DI) model. Moreover, we tested thigh cuffs as a countermeasure to prevent potential microgravity-induced modifications in rCBF. Around 18 healthy male participants underwent 5-day DI with or without a thigh cuffs countermeasure. They were randomly allocated to a control (n=9) or cuffs (n=9) group. rCBF was measured 4days before DI and at the end of the fifth day of DI (DI5), using single-photon emission computed tomography (SPECT) with radiopharmaceutical 99mTc-hexamethyl propylene amine oxime (99mTc-HMPAO). SPECT images were processed using statistical parametric mapping (SPM12) software. At DI5, we observed a significant decrease in rCBF in 32 cortical and subcortical regions, with greater hypoperfusion in basal ganglia (right putamen peak level: z=4.71, puncorr<0.001), bilateral occipital regions (left superior occipital peak level: z=4.51, puncorr<0.001), bilateral insula (right insula peak level: 4.10, puncorr<0.001), and bilateral inferior temporal (right inferior temporal peak level: 4.07, puncorr<0.001). No significant difference was found between the control and cuffs groups on change in rCBF after 5days of DI. After a 5-day DI, we found a decrease in rCBF in cortical and subcortical regions. However, thigh cuffs countermeasure failed to prevent hypoperfusion. To date, this is the first study measuring rCBF in DI. Further investigations are needed in order to better understand the underlying mechanisms in cerebral blood flow (CBF) changes after exposure to microgravity.

Biomarkers and Fever in Children with Cancer: Kinetics and Levels According to Final Diagnosis

We investigated the kinetics of CRP, PCT, IL-6 and MR-proADM in a cohort of consecutive febrile patients with cancer in order to test the hypothesis that higher plasma concentrations and the absence of a rapid decrease in peak values would be associated with disease severity. (1) Method: A prospective descriptive and analytical study of patients with cancer and fever (≤18 years of age) at a University Hospital was carried out between January 2018 and December 2019. Information collected: sex, age, diagnosis, date and symptoms at diagnosis and medical history. The episodes were classified into three groups: bacterial infection, non-bacterial infection and systemic inflammatory response syndrome (SIRS). (2) Results: One hundred and thirty-four episodes were included. Bacterial infection criteria were met in 38 episodes. Biomarkers were measured at four different points: baseline, at 12–24 h, at 25–48 h and at 49–72 h. All the biomarkers evaluated decreased after the peak level was reached. IL-6 and MR-proADM showed a trend towards higher levels in the SIRS group although this rise was statistically significant only for IL-6 (p < 0.005). Bacterial infections more frequently presented values of PCT above the cut-off point (>0.5 ng/mL) at 12–24 h. (3) Conclusion: In our experience, IL-6 kinetics is faster than PCT kinetics and both are faster than CRP in patients with fever and cancer who present a good outcome. Patients with a good evolution show a rapid increase and decrease of PCT and particularly of IL-6 levels.

Aberrant Changes in Cortical Complexity in Right-Onset Versus Left-Onset Parkinson’s Disease in Early-Stage

There is increasing evidence to show that motor symptom lateralization in Parkinson’s disease (PD) is linked to non-motor features, progression, and prognosis of the disease. However, few studies have reported the difference in cortical complexity between patients with left-onset of PD (LPD) and right-onset of PD (RPD). This study aimed to investigate the differences in the cortical complexity between early-stage LPD and RPD. High-resolution T1-weighted magnetic resonance images of the brain were acquired in 24 patients with LPD, 34 patients with RPD, and 37 age- and sex-matched healthy controls (HCs). Cortical complexity including gyrification index, fractal dimension (FD), and sulcal depth was analyzed using surface-based morphometry via CAT12/SPM12. Familywise error (FWE) peak-level correction at p &lt; 0.05 was performed for significance testing. In patients with RPD, we found decreased mean FD and mean sulcal depth in the banks of the left superior temporal sulcus (STS) compared with LPD and HCs. The mean FD in the left superior temporal gyrus (STG) was decreased in RPD compared with HCs. However, in patients with LPD, we did not identify significantly abnormal cortical complex change compared with HCs. Moreover, we observed that the mean FD in STG was negatively correlated with the 17-item Hamilton Depression Scale (HAMD) among the three groups. Our findings support the specific influence of asymmetrical motor symptoms in cortical complexity in early-stage PD and reveal that the banks of left STS and left STG might play a crucial role in RPD.