Improving water quality and mitigating CH4 and N2O production in urban landscape water simultaneously by optimizing calcium peroxide dosage

Recent studies show that greenhouse gas (GHG) emissions from urban landscape water are significant and cannot be overlooked, underscoring the need to develop effective strategies for mitigating GHG production from global freshwater systems. Calcium peroxide (CaO2) is commonly used as an eco-friendly reagent for controlling eutrophication in water bodies, but whether CaO2 can reduce GHG emissions remains unclear. This study investigated the effects of CaO2 dosage on the production of methane (CH4) and nitrous oxide (N2O) in urban landscape water under anoxic conditions during summer. The findings reveal that CaO2 addition not only improved the physicochemical and organoleptic properties of simulated urban landscape water but also reduced N2O production by inhibiting the activity of denitrifying bacteria across various dosages. Moreover, CaO2 exhibited selective effects on methanogens. Specifically, the abundance of acetoclastic methanogen Methanosaeta and methylotrophic methanogen Candidatus_Methanofastidiosum increased whereas the abundance of the hydrogenotrophic methanogen Methanoregula decreased at low, medium, and high dosages, leading to higher CH4 production at increased CaO2 dosage. A comprehensive multi-objective evaluation indicated that an optimal dosage of 60 g CaO2/m2 achieved 41.21 % and 84.40 % reductions in CH4 and N2O production, respectively, over a 50-day period compared to the control. This paper not only introduces a novel approach for controlling the production of GHGs, such as CH4 and N2O, from urban landscape water but also suggests a methodology for optimizing CaO2 dosage, providing valuable insights for its practical application.

Suppression of thermo-acoustic instabilities in horizontal Rijke tube using pulsating radial jets

Thermo-acoustic instability has been observed in gas turbines, rocket engines, and aero-engines. Acoustic perturbations grow and change the characteristics of the flow due to instability. The present work describes the use of pulsating air jets to suppress the thermo-acoustic instabilities. In present study pulsatile micro-jets are placed downstream of the burner radially which breaks the coupling between acoustic waves and unsteady heat release. A microphone connected to LIFA (LabVIEW Interface for Arduino) was used to detect the sound pressure levels. By controlling the airflow rate of the pulsatile jets, the sound pressure levels were suppressed down to the background noise level using minimum energy and time. A closed-loop control system is developed for this purpose, which works on the feedback signal acquired from microphone. To simulate the one dimensional combustion phenomenon, an experimental setup called Rijke tube was used. The suppression was most effective for the pulsatile jets of 27-33 Hz pulsation frequency range and at a flow rate of 6.8 LPM. This control strategy effectively controlled the combustion instability of around 35-42 dB.•The closed loop control method is built on DAQ and Arduino using the LabVIEW interface for Arduino (LIFA).•Developed closed loop active control method was observed to be effective for suppression of thermo-acoustic instability.•Optimum position of the radial planes of micro-jets with respect to the burner was decided to improve the efficacy of the pulsatile jets towards suppression of thermo-acoustic instability.

Analysis on electric impedance-controlled active ultrasonic horn in radial vibration

As a key component of high-powered ultrasonic vibration systems, ultrasonic horns play an important role in various practical application scenarios. Recent advances in longitudinal ultrasonic horns have enabled them to magnify the Langevin transducer's mechanical vibration and efficiently transmit the mechanical vibration to the mechanical load. However, limited research has been devoted to active radial ultrasonic horns in radial vibration. Here we propose an electric impedance-controlled active radial ultrasonic horn (ARUH) capable of tuning both resonance frequency and displacement magnification in radial vibration. The resulting device consists of a radially polarized piezoelectric ring connected with adjustable electric impedance and two metal rings with variable sections. The underlying mechanism is that the change of the converted mechanical impedance of the piezoelectric material by the external electric impedance connected to the piezoelectric material modulates the resonance frequency and displacement magnification of the ARUH. It can be found that the resonant frequency shifts to higher frequencies as the resistance increases and the resonant frequency shifts to lower frequencies as the inductance and capacitance increase, while the displacement magnification has the opposite trend to the resonance frequency. For example, the resonance frequency of the constant-section radial horn is 41130.2 Hz. When the inductance increases from -0.007 to 0.007H, the resonance frequency shifts from 41171.3 to 34606.2 Hz and the displacement magnification moves from 1.189 to 3.5. The experiments are conducted to verify the effectiveness of the resulting device, which is in good agreement with the simulated results and theoretical predictions. Our design with functionality and flexibility opens up possibilities for the design of ARUHs and may find important application prospects in diverse fields such as cold-drawn steel tubes and ultrasonic plastic welding.

mHealth intervention delivered in general practice to increase physical activity and reduce sedentary behaviour of patients with prediabetes and type 2 diabetes (ENERGISED): rationale and study protocol for a pragmatic randomised controlled trial

BACKGROUND

The growing number of patients with type 2 diabetes and prediabetes is a major public health concern. Physical activity is a cornerstone of diabetes management and may prevent its onset in prediabetes patients. Despite this, many patients with (pre)diabetes remain physically inactive. Primary care physicians are well-situated to deliver interventions to increase their patients' physical activity levels. However, effective and sustainable physical activity interventions for (pre)diabetes patients that can be translated into routine primary care are lacking.

METHODS

We describe the rationale and protocol for a 12-month pragmatic, multicentre, randomised, controlled trial assessing the effectiveness of an mHealth intervention delivered in general practice to increase physical activity and reduce sedentary behaviour of patients with prediabetes and type 2 diabetes (ENERGISED). Twenty-one general practices will recruit 340 patients with (pre)diabetes during routine health check-ups. Patients allocated to the active control arm will receive a Fitbit activity tracker to self-monitor their daily steps and try to achieve the recommended step goal. Patients allocated to the intervention arm will additionally receive the mHealth intervention, including the delivery of several text messages per week, with some of them delivered just in time, based on data continuously collected by the Fitbit tracker. The trial consists of two phases, each lasting six months: the lead-in phase, when the mHealth intervention will be supported with human phone counselling, and the maintenance phase, when the intervention will be fully automated. The primary outcome, average ambulatory activity (steps/day) measured by a wrist-worn accelerometer, will be assessed at the end of the maintenance phase at 12 months.

DISCUSSION

The trial has several strengths, such as the choice of active control to isolate the net effect of the intervention beyond simple self-monitoring with an activity tracker, broad eligibility criteria allowing for the inclusion of patients without a smartphone, procedures to minimise selection bias, and involvement of a relatively large number of general practices. These design choices contribute to the trial's pragmatic character and ensure that the intervention, if effective, can be translated into routine primary care practice, allowing important public health benefits.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT05351359, 28/04/2022).

Bimekizumab Efficacy and Safety in Japanese Patients with Plaque Psoriasis in BE VIVID: A Phase 3, Ustekinumab and Placebo-Controlled Study

INTRODUCTION

Bimekizumab treatment resulted in improved clinical outcomes in patients with moderate-to-severe plaque psoriasis in BE VIVID, a 52-week, phase 3, randomized, ustekinumab and placebo-controlled study. We present data from the BE VIVID Japan patient subpopulation.

METHODS

Globally, patients were randomized to receive bimekizumab 320 mg every 4 weeks (Q4W), ustekinumab (45/90 mg weight-based at baseline and week 4, then every 12 weeks), or placebo (Q4W through week 16, then bimekizumab 320 mg Q4W). Efficacy endpoints included week 16 Psoriasis Area and Severity Index (PASI) 90 and Investigator's Global Assessment (IGA) 0/1, and other outcomes [PASI 100, PASI 75, IGA 0, Dermatology Life Quality Index (DLQI) 0/1, absolute PASI, scalp IGA, Psoriasis Symptoms and Impacts Measure (P-SIM) responses]. Safety analyses were conducted.

RESULTS

There were 108 Japanese randomized patients (bimekizumab: 62; ustekinumab: 29; placebo: 17). At week 16, bimekizumab-treated patients had a higher clinical response versus ustekinumab and placebo (PASI 90: 85.5% versus 51.7% and 5.9%; IGA 0/1: 82.3% versus 48.3% and 0.0%). Over 52 weeks, improved clinical response was maintained with bimekizumab, including patients switching from placebo at week 16. Overall, the safety profile in Japanese patients was consistent with that observed in the global population.

CONCLUSION

Bimekizumab resulted in improved clinical response versus ustekinumab and placebo, and was well-tolerated in Japanese patients.

TRIAL REGISTRATION

NCT03370133.

Experimental method for temperature measurement on lateral planes along a Rijke tube to assess efficacy of control method

The thermo-acoustic instabilities developed inside the combustor causes serious structural damage and reduces the life of power producing devices. The present work involves experimental investigation to assess effect of radial micro-jets air injection on thermo-acoustic instabilities and temperature in lateral planes. A co-axial pre-mixed gas burner used as the heat source inside the Rijke tube with variable location. Two types of Rijke tubes were used for experimental study, one is of steel with 75 mm internal diameter and 750 mm in length for the measurement of wall pressure, temperature and acoustics. •In the first part of the study, acoustic instability zone for different inlet mass flow rates was identified.•In the second part of study, the entire cross-sectional of Rijke tube was divided into 193 subzones and temperatures were measured at 193 locations when instability was present.•In third part, again temperatures were measured at 193 locations with implementation of control method with complete suppression of thermo-acoustic instabilities.

Optimization of in-pipe storage capacity use in urban drainage systems with improved DP considering the time lag of flow routing

The active control of urban drainage systems (UDSs) is playing an increasingly important role in the world threatened by urban flooding and associated disasters caused by insufficient drainage capacity. However, little research has recognized the importance of the optimal use of in-pipe storage space. To address this issue, the use of the in-pipe storage capacity was optimized in this study. A novel approach, that is, dynamic programming with successive approximation considering the time lag of flow routing (DPSA-TL), was developed to determine the control policies, in addition to the commonly used passive, rule-based control (RBC), and evolutionary algorithm (EA) strategies. A real-life urban catchment considering flooding control and combined sewer overflow (CSO) reduction was used as the case study. First of all, the potential benefit of maximizing the use of in-pipe storage space was tested using the four control strategies in three storm events, including a 3-year, 2-hour design (46.5 mm), a 5-year, 2-hour design (56.0 mm) and a 7-h historical (152.5 mm) storm events. Results indicate that DPSA-TL performed best in all cases. Without compromising the goal of flooding control, it provided 16.5%, 12.6%, and 3.0% reductions in CSO volume for the three storm events when compared with the passive strategy. Due to the limited capacity of in-pipe storage, the relative improvement diminished as the total rainfall depth increased. Then, control strategies were further applicated to the real-time operation. DPSA-TL was found to be the best alternative for CSO control, with the CSO volume reduced by 14.7%, 11.4%, and 2.5% in the three storm events, respectively. The findings suggest that the performance of UDS can be significantly improved by optimizing the use of in-pipe storage capacity, and the proposed method is effective in the offline optimization and real-time control of UDSs.

Mindfulness, anxiety, and perceived stress in university students: Comparing a mindfulness-based intervention (MBI) against active and traditional control conditions

ObjectivesUniversity students experience heightened levels of stress and are seeking mental health services with increasing frequency. Mindfulness-based interventions (MBIs) may be an effective resource for managing stress. The present study examined the effectiveness of an MBI in reducing stress, anxiety, and rumination compared to active and traditional control conditions.MethodsUndergraduate students at a southeastern university participated in either a 4-week MBI, active control, or traditional control condition. Measures were collected pre- and post-intervention. Results: Overall the MBI had a significant impact on perceived stress over and above both traditional and active control conditions. The MBI also had a significant impact on trait mindfulness and anxiety compared to the traditional control condition. No significant differences were observed for rumination. Conclusions: The MBI significantly impacted trait mindfulness, perceived stress, and state anxiety. MBIs may be a useful approach to successfully alleviating stress in a highly stressed population.

Moving to a future of smart stormwater management: A review and framework for terminology, research, and future perspectives

Stormwater hazards are a significant threat across the globe. These are continuing to increase in line with urbanisation and climate change, leading to a recognition that the historic paradigm of passive management using centralised infrastructure is insufficient to manage future hazards to our society, environment, and economy. The cross-sector Internet of Things revolution has inspired a new generation of smart stormwater management systems which offer an effective, cost beneficial and adaptive solution to enhance network capacities and reduce hazards. However, despite growing prominence within research, this technology remains under-utilised, in a large part due to fragmented and inconsistent alignment and terminology, obscuring the strategic co-ordination of research. We respond to this through systematically reviewing the terminology, practice and trajectory for smart stormwater management and developing a framework which can be applied to both coordinate and understand the existing research landscape, as well as identifying key research gaps for future development. We find that literature almost universally agrees that smart technology is, or will be, beneficial to stormwater management and that technology has reached partial maturity in terms of quantity management, although this has not yet transferred to water quality. However, research is dominated by proof-of-concept modelling studies, with limited practical application beyond real time control of large assets, individual pilot studies and monitoring. We recommend that future research explores and evidences the substantial benefits likely through expanding current implementation towards a coordinated, decentralised, and optimised catchment-scale approach.

Active and synchronous control of nitrogen and organic matter release from sediments induced with calcium peroxide

In order to realize the active and synchronous control of nitrogen (N) and organic matter (OM) release from sediments, this study compared the spatiotemporal changes in the physical, chemical, and biological indicators in the water system under different CaO₂ dosing modes. Results from 90-day incubation experiment showed that CaO₂ formed a dense barrier layer near its dosing position, improved the anoxic condition of water system, increased the physical adsorption of pollutants by sediments, and reduced the nutrients in overlying water, interstitial water, and sediments. Comprehensive comparison, the improvement effect of shallow injection group (I1) was the most obvious. Meanwhile, the activities of ammonia oxidizing bacteria and nitrite oxidizing bacteria near dosing position and those of denitrifiers and anammox bacteria adjacent to dosing site were significantly increased in all test groups (p < 0.01), thereby realizing the biological removal of N and OM in sediments. In addition, DO and ORP were steadily higher than 5 mg L^-1 and 100 mV in I1, where the NH₄⁺-N concentration in overlying water was stable below 1 mg L^-1, and the easily released N content in the upper (0-3 cm) and middle (4-6 cm) sediments decreased by 41.64% and 43.56%, respectively. Compared with the large pollutant flux in control (14.31 TN mg m^-2 d^-1 and 194.05 mg TCOD m^-2 d^-1), I1 completely inhibited the pollutant release and reduced the original nutrients in overlying water. In general, CaO₂ efficiently and synchronously controlled the endogenous release of N and OM under the combined actions of physical interception, physical adsorption, chemical oxidation, and biological transformation. Therefore, this study may provide valuable reference and guidance for the active and synchronous removal of N and OM in sediments and inhibition of endogenous pollutant release under anoxic condition.

Cognitive skill training improves memory, function, and use of cognitive strategies in cancer survivors

BACKGROUND

Cancer survivors commonly report symptoms of impaired cognition. This project examined effectiveness of a behavioral skills training intervention to improve cognition and reduce cognitive dysfunction symptoms in cancer survivors.

METHODS

Participants were randomly assigned to group-based workshops focused on learning new cognitive skills (skills treatment-TX) or an active control of education workshops (education control-EC) or a passive control of wait list (WL). Participants were evaluated pre- and post intervention with subjective mood and symptom questionnaires and objective neurocognitive tests.

RESULTS

One hundred twenty-eight participants (mean age 59 years), average 4.6 years (+ / - 5.5 years) post cancer treatment with various cancer types (breast, bladder, prostate, colon, uterine), were enrolled. Analysis of all participants who attended workshop(s) revealed improvement in the TX workshop completers on all objective cognitive measures (attention, concentration, declarative, and working memory) save one test of selective attention, and improvement on a single measure (verbal memory) and decline (selective attention) in the EC group. TX workshop completers also improved on all symptom and mood measures, in contrast to EC group which improved on a single subscale of a symptom measure, but increased on an anxiety measure. TX group alone improved on a quantified measure of each participants' unique, "top three," self-described cognitive symptoms.

CONCLUSION

Improvement from behavioral skills training was evident from objective cognitive tests, subjective symptom measures, and quantified, individual patient-specific symptoms. Behavioral skill training is an effective treatment for cognitive dysfunction in cancer survivors, and should be considered as a treatment option by health care providers.

A review of mathematical model-based scenario analysis and interventions for COVID-19

Mathematical model-based analysis has proven its potential as a critical tool in the battle against COVID-19 by enabling better understanding of the disease transmission dynamics, deeper analysis of the cost-effectiveness of various scenarios, and more accurate forecast of the trends with and without interventions. However, due to the outpouring of information and disparity between reported mathematical models, there exists a need for a more concise and unified discussion pertaining to the mathematical modeling of COVID-19 to overcome related skepticism. Towards this goal, this paper presents a review of mathematical model-based scenario analysis and interventions for COVID-19 with the main objectives of (1) including a brief overview of the existing reviews on mathematical models, (2) providing an integrated framework to unify models, (3) investigating various mitigation strategies and model parameters that reflect the effect of interventions, (4) discussing different mathematical models used to conduct scenario-based analysis, and (5) surveying active control methods used to combat COVID-19.

Suppression of Malachite Green-Induced Toxicity to Human Liver Cells Utilizing Host-Guest Chemistry of Cucurbit[7]uril

We investigated a host-guest complex between cucurbit[7]uril and malachite green, and its effect on the toxicity to human liver cells. The host-guest complexation was evaluated by a UV/vis titration and electrospray-ionization mass spectrometry. Interestingly, the host-guest complex resulted in remarkable suppression of the toxicity of malachite green in its practical concentration range (ca. ∼6 μM). This study is one step forward to the active control of the biological effects of potent toxicants utilizing host-guest chemistry.

Numerical study of the impact of water injection holes arrangement on cavitation flow control

A method of water injection to flow field using distributed holes on the suction surface of hydrofoil is presented in this article to control cavitation flow. Modified renormalization group k-ε turbulence model is coupled with full-cavitation model to calculate periodical cavitation patterns and the dynamic characteristics of the NACA66(MOD) hydrofoil. Water injection is found to be highly effective for cavitation suppression. The cavitation suppression effect of distributed regulation of jet holes and porosities along three-dimensional spanwise hydrofoil is also investigated. The appropriate porosities of single row spanwise jet holes and optimal jet position of double row jet holes are revealed for both cavitation suppression and good hydrodynamic performance. Double row jet holes setting in forward trapezoidal arrangement shows great potential for cavitation suppression and hydrodynamic performance. This research provides a method of water injection to flow field to actively control cavitation, which will facilitate development of engineering designs.

Cognitively-Based Compassion Training versus cancer health education to improve health-related quality of life in survivors of solid tumor cancers and their informal caregivers: study protocol for a randomized controlled pilot trial

Background

Cancer survivors and their informal caregivers (family members, close friends) often experience significant impairments in health-related quality of life (HRQOL), including disruptions in psychological, physical, social, and spiritual well-being both during and after primary cancer treatment. The purpose of this in-progress pilot trial is to determine acceptability and preliminary efficacy (as reflected by effect sizes) of CBCT® (Cognitively-Based Compassion Training) compared with a cancer health education (CHE) attention control to improve the primary outcome of depressive symptoms and secondary outcomes of other HRQOL domains (e.g., anxiety, fatigue), biomarkers of inflammation and diurnal cortisol rhythm, and healthcare utilization-related outcomes in both cancer survivors and informal caregivers.

Methods

Forty dyads consisting of solid tumor survivors who have completed primary treatments (chemotherapy, radiation, surgery) and their informal caregivers, with at least one dyad member with ≥ mild depressive symptoms or anxiety, will be recruited from Tucson, Arizona, USA. Survivor-caregiver dyads will be randomized together to complete either CBCT or CHE. CBCT is a manualized, 8-week, group meditation-based intervention that starts with attention and mindfulness and builds to contemplative practices aimed at cultivating compassion to the self and others. The goal of CBCT is to challenge unexamined assumptions about feelings and behaviors, with a focus on generating spontaneous self-compassion and increased empathic responsiveness and compassion for others. CHE is an 8-week, manualized group intervention that provides cancer-specific education on various topics (e.g., cancer advocacy, survivorship wellness). Patient-reported HRQOL outcomes will be assessed before, immediately after (week 9), and 1 month after CBCT or CHE (week 13). At the same time points, stress-related biomarkers of inflammation (e.g., plasma interleukin-6) and saliva cortisol relevant for survivor and informal caregiver wellness and healthcare utilization will be measured.

Discussion

If CBCT shows acceptability, a larger trial will be warranted and appropriately powered to formally test the efficacy of this dyadic intervention. Interventions such as CBCT directed toward both survivors and caregivers may eventually fill a gap in supportive oncology care programs to improve HRQOL and healthcare utilization in both dyad members.

Trial registration

Clinicaltrials.gov, NCT03459781. Prospectively registered on 9 March 2018.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3320-9) contains supplementary material, which is available to authorized users.

Active control as evidence in favor of sense of ownership in the moving Virtual Hand Illusion

The sense of ownership, the feeling that our body belongs to ourselves, relies on multiple sources of sensory information. Among these sources, the contribution of visuomotor information is still debated. We tested the effect of active control in the sense of ownership in the moving Virtual Hand Illusion. Participants reported sense of ownership and sense of agency over a virtual arm in which we manipulated the morphological congruence of the hand and the visuomotor information. We found that congruent active control enhanced and maintained the reported sense of ownership over a hand that appeared detached from the body, but not in a morphological congruent limb. Also, incongruent active control, achieved by adding noise to the trajectory of the movement, decreased both reported sense of agency and ownership. Overall, our results are consistent with a framework in which active control acts as evidence for eliciting a sense of ownership.

Low-Cost and Active Control of Radiation of Wearable Medical Health Device for Wireless Body Area Network

Wearable devices, wireless networks and body area networks have become an effective way to solve the problem of human health monitoring and care. However, the radiation problems of wireless devices, the power supply problems of wearable devices and the deployment of body area networks have become obstacles to their wide application in the field of health care. In order to solve the above problems, this paper studies and designs a wearable health medical body area network which is convenient for human health monitoring and medical care, starting from low-cost deployment of wireless wearable devices and active control of wireless radiation. Firstly, in order to avoid replacing equipment batteries, improve the relay and data aggregation capabilities of wireless body area network, and reduce the communication and computing load of edge devices, a deployment scheme of wireless medical health wearable devices is designed based on the optimal segmentation algorithm of Steiner spanning tree. Then, in order to minimize the charging cost and maximize the global charging utility of single source and multiple points in a finite time slot, an approximate algorithm for the optimal charging sequence based on 01 knapsack problem, i.e., the access path of wireless wearable devices, is designed. Then, an active radiation control algorithm for wearable medical health body area network is proposed, which can actively control the transmission power and radiation status of these wireless devices. Finally, simulation results show that the proposed algorithm is better than battery-powered wireless body area network and wireless rechargeable body area network, 16% and 44% reduction of devices, 25%13% reduction of energy consumption, 26% reduction of radiation, and 5.18 and 1.13 times improvement of signal quality.

The more I got, the less I need? Efficacy of Internet-based guided self-help compared to online psychoeducation for major depressive disorder

BACKGROUND

This study's aims were to compare the efficacy and negative effects of guided Internet-based cognitive behavior therapy (iCBT) and online psychoeducation (OPE) in people with major depression.

METHODS

A total of 131 individuals were randomized. Assessments took place at baseline (T1), six weeks (T2), and three months (T3). The primary endpoint was change in observer-based depression severity from T1 to T2. Potential negative effects were analyzed in terms of suicidal ideations, symptom deterioration, attitudes toward seeking further help, and other adverse events.

RESULTS

iCBT (n = 65) and OPE (n = 66) both reduced depressive symptoms from T1 to T2, with large changes observed for iCBT and medium for OPE (iCBT: Cohen's d = 1.09; OPE: d = 0.60). Differences between groups were significant at the primary endpoint (d = 0.36, p = 0.028). OPE continued to have a positive effect from post-treatment to follow-up, while the effect of iCBT remained stable, with differences between groups not being significant anymore at follow-up. Participants who had undergone prior psychotherapy benefited from both treatments; but for those without prior psychotherapy, iCBT was superior also at follow-up. In the iCBT group 26.2% of the participants reported at least one side-effect.

LIMITATIONS

The history of psychotherapy was imbalanced between the groups. Some negative effects were assessed in the iCBT group only.

CONCLUSIONS

Both iCBT and OPE were effective in reducing depressive symptoms, but with iCBT having a more rapid effect. iCBT was specifically superior in those with no prior history of psychotherapy. Negative effects occurred frequently and should be considered when implementing iCBT.

TRIAL REGISTRATION

German clinical trials register: DRKS00005025.

Active control of properties of concrete: a (p)review

Concrete properties to a large extent depend on mix design and processing, currently leaving only limited options to actively modify concrete properties during or after casting. This paper gives a (p)review on a more advanced active control of properties of concrete, based on the application of external signals to trigger an intended response in the material, either in fresh or hardened state. Current practices in concrete industry that could be considered as active control are briefly summarized. More advanced active control mechanisms as studied in other fields, e.g. based on hydrogels and other functional polymers, are reviewed and some principles are listed. A specific focus is further given on potential methods for active rheology control. Based on the concepts developed in other fields, substantial progress could be made in order to achieve active control of fresh and hardened concrete properties. However, several challenges remain, like the stability and functioning of the responsive material in a cementitious environment, the applicability of the control signal in a cementitious material, and the economy, logistics and safety of a control system on a construction site or in precast industry. Finding solutions to these challenges will lead to marvelous opportunities in general, and for 3D and even 4D printing more particularly.

Design of a noninvasive and smart hand tremor attenuation system with active control: a simulation study

This paper presents the design and simulation of a handheld device for people with hand tremor, such as Parkinson's and essential tremor patients. This device can be used as a pen for smartphones or as a spoon. The designed system includes two links, which are connected to two servomotors, which are mounted in orthogonal directions. To attenuate the effect of hand tremor on the tip of device, PID and computed torque methods are used to actively control the system. These controllers are used to control the rotation of the motors for moving the links in opposite directions of the hand tremor. Performance of the device with mentioned controllers is studied for different applications and finally, the results of both controllers are discussed and compared. Based on the presented results in this study, the designed device is able to suppress the hand tremor up to 75% during eating and 65% during following a spiral pattern. Graphical abstract Design of a noninvasive and smart hand tremor attenuation system: a simulation study.

Disturbance observer based active and adaptive synchronization of energy resource chaotic system

In this paper, synchronization of a three-dimensional energy resource chaotic system is considered. For the sake of achieving the synchronization between the drive and response systems, two different nonlinear control approaches, i.e. active control with known parameters and adaptive control with unknown parameters, have been designed. In order to guarantee the transient performance, finite-time boundedness (FTB) and finite-time stability (FTS) are introduced in the design of active control and adaptive control, respectively. Simultaneously, in view of the existence of disturbances, a new disturbance observer is proposed to estimate the disturbance. The conditions of the asymptotic stability for the closed-loop system are obtained. Numerical simulations are provided to illustrate the proposed approaches.

Evaluation of Physiological Control Systems for Rotary Left Ventricular Assist Devices: An In-Vitro Study

Rotary left ventricular assist devices (LVADs) show weaker response to preload and greater response to afterload than the native heart. This may lead to ventricular suction or pulmonary congestion, which can be deleterious to the patient's recovery. A physiological control system which optimizes responsiveness of LVADs may reduce adverse events. This study compared eight physiological control systems for LVAD support against constant speed mode. Pulmonary (PVR) and systemic (SVR) vascular resistance changes, a passive postural change and exercise were simulated in a mock circulation loop to evaluate the controller's ability to prevent suction and congestion and to increase exercise capacity. Three active and one passive control systems prevented ventricular suction at high PVR (500 dyne s cm(-5)) and low SVR (600 dyne s cm(-5)) by decreasing LVAD speed (by 200-515 rpm) and by increasing LVAD inflow cannula resistance (up to 1000 dyne s cm(-5)) respectively. These controllers increased LVAD preload sensitivity (to 0.196-2.415 L min(-1) mmHg(-1)) compared to the other control systems and constant speed mode (0.039-0.069 L min(-1) mmHg(-1)). The same three active controllers increased pump speed (600-800 rpm) and thus LVAD flow by 4.5 L min(-1) during exercise which increased exercise capacity. Physiological control systems that prevent adverse events and/or increase exercise capacity may help improve LVAD patient conditions.

In Vivo Evaluation of Active and Passive Physiological Control Systems for Rotary Left and Right Ventricular Assist Devices

Preventing ventricular suction and venous congestion through balancing flow rates and circulatory volumes with dual rotary ventricular assist devices (VADs) configured for biventricular support is clinically challenging due to their low preload and high afterload sensitivities relative to the natural heart. This study presents the in vivo evaluation of several physiological control systems, which aim to prevent ventricular suction and venous congestion. The control systems included a sensor-based, master/slave (MS) controller that altered left and right VAD speed based on pressure and flow; a sensor-less compliant inflow cannula (IC), which altered inlet resistance and, therefore, pump flow based on preload; a sensor-less compliant outflow cannula (OC) on the right VAD, which altered outlet resistance and thus pump flow based on afterload; and a combined controller, which incorporated the MS controller, compliant IC, and compliant OC. Each control system was evaluated in vivo under step increases in systemic (SVR ∼1400-2400 dyne/s/cm(5) ) and pulmonary (PVR ∼200-1000 dyne/s/cm(5) ) vascular resistances in four sheep supported by dual rotary VADs in a biventricular assist configuration. Constant speed support was also evaluated for comparison and resulted in suction events during all resistance increases and pulmonary congestion during SVR increases. The MS controller reduced suction events and prevented congestion through an initial sharp reduction in pump flow followed by a gradual return to baseline (5.0 L/min). The compliant IC prevented suction events; however, reduced pump flows and pulmonary congestion were noted during the SVR increase. The compliant OC maintained pump flow close to baseline (5.0 L/min) and prevented suction and congestion during PVR increases. The combined controller responded similarly to the MS controller to prevent suction and congestion events in all cases while providing a backup system in the event of single controller failure.

New methods for treatment effect calibration, with applications to non-inferiority trials

In comparative effectiveness research, it is often of interest to calibrate treatment effect estimates from a clinical trial to a target population that differs from the study population. One important application is an indirect comparison of a new treatment with a placebo control on the basis of two separate randomized clinical trials: a non-inferiority trial comparing the new treatment with an active control and a historical trial comparing the active control with placebo. The available methods for treatment effect calibration include an outcome regression (OR) method based on a regression model for the outcome and a weighting method based on a propensity score (PS) model. This article proposes new methods for treatment effect calibration: one based on a conditional effect (CE) model and two doubly robust (DR) methods. The first DR method involves a PS model and an OR model, is asymptotically valid if either model is correct, and attains the semiparametric information bound if both models are correct. The second DR method involves a PS model, a CE model, and possibly an OR model, is asymptotically valid under the union of the PS and CE models, and attains the semiparametric information bound if all three models are correct. The various methods are compared in a simulation study and applied to recent clinical trials for treating human immunodeficiency virus infection.

In Vitro Comparison of Active and Passive Physiological Control Systems for Biventricular Assist Devices

The low preload and high afterload sensitivities of rotary ventricular assist devices (VADs) may cause ventricular suction events or venous congestion. This is particularly problematic with rotary biventricular support (BiVAD), where the Starling response is diminished in both ventricles. Therefore, VADs may benefit from physiological control systems to prevent adverse events. This study compares active, passive and combined physiological controllers for rotary BiVAD support with constant speed mode. Systemic (SVR) and pulmonary (PVR) vascular resistance changes and exercise were simulated in a mock circulation loop to evaluate the capacity of each controller to prevent suction and congestion and increase exercise capacity. All controllers prevented suction and congestion at high levels of PVR (900 dynes s cm(-5)) and SVR (3000 dynes s cm(-5)), however these events occurred in constant speed mode. The controllers increased preload sensitivity (0.198-0.34 L min(-1) mmHg(-1)) and reduced afterload sensitivity (0.0001-0.008 L min(-1) mmHg(-1)) of the VADs when compared to constant speed mode (0.091 and 0.072 L min(-1) mmHg(-1) respectively). The active controller increased pump speeds (400-800 rpm) and pump flow by 2.8 L min(-1) during exercise, thus increasing exercise capacity. By reducing suction and congestion and by increasing exercise capacity, the control systems presented in this study may help increase quality of life of VAD patients.

Robust pole assignment using velocity-acceleration feedback for second-order dynamical systems with singular mass matrix

In this paper the robust pole assignment problem using combined velocity and acceleration feedback for second-order linear systems with singular mass matrix is illustrated. This is promising for better applicability in several practical applications where the acceleration signals are easier to obtain than the proportional ones. First, the explicit parametric expressions of both the feedback gain controller and the eigenvector matrix are derived. The parametric solution involves manipulations only on the original second-order model. The available degrees of freedom offered by the velocity-acceleration feedback in selecting the associated eigenvectors are utilized to improve robustness of the closed-loop system. Straight-forward computational algorithms are introduced to demonstrate the effectiveness of the proposed approach. These algorithms are applicable for a dynamical system with mass matrices that can be either singular or nonsingular. Numerical examples are provided to illustrate the application of the proposed procedure.

Point and Interval Estimators of the Target Dose in Clinical Dose-Finding Studies with Active Control

In a clinical dose finding study with active control a new drug with several dose levels is compared with an active comparator drug. The main focus of such studies often lies on the estimation of a target dose that leads to the same efficacy as the control. This article investigates the finite sample properties of the maximum likelihood estimation of the target dose and compares several approaches for constructing corresponding confidence intervals under the assumption of a linear dose-response curve and normal error terms. Furthermore, the impact of deviations from the model assumptions regarding the error distribution is explored.