Time Integral Research Articles

Teaching in the Digital Age-Developing a Support Program for Nursing Education Providers: Design-Based Research.

Health care systems and the nursing profession worldwide are being transformed by technology and digitalization. Nurses acquire digital competence through their own experience in daily practice, but also from education and training; nursing education providers thus play an important role. While nursing education providers have some level of digital competence, there is a need for ongoing training and support for them to develop more advanced skills and effectively integrate technology into their teaching. This study aims to develop a needs-based support program for nursing education providers to foster digital competencies and to test this intervention. We used a design-based research approach, incorporating iterative development with expert consultation to create and evaluate a support program for nursing education providers. Focus groups were conducted online to assess needs, and thematic content analysis was used to derive key insights. The support program was then refined through expert feedback and subjected to a feasibility and satisfaction test, with participant evaluations analyzed descriptively. Six main categories emerged from the focus groups, highlighting key areas, including the use of digital technology, ongoing support needs, and the current state of digitalization in nursing education. The support program was developed based on these findings, with expert validation leading to adjustments in timing, content prioritization, and platform integration. Preliminary testing showed good overall satisfaction with the support program, although participants suggested improvements in content relevance and digital platform usability. Although the feasibility test showed high satisfaction with the support program, low participation rates and limited perceived knowledge gain were major concerns. The results suggest that while the program was well received, further refinements, including a focus on competency-based approaches and addressing workplace barriers, are needed to increase participation and effectiveness of such interventions. The findings of this research can be used as a basis for the development of similar programs in other educational and health care contexts.

Efficient pressure regulation in nonlinear shell-and-tube steam condensers via a Novel TDn(1 + PIDn) controller and DCSA algorithm

Steam condensers are vital components of thermal power plants, responsible for converting turbine exhaust steam back into water for reuse in the power generation cycle. Effective pressure regulation is crucial to ensure operational efficiency and equipment safety. However, conventional control strategies, such as PI, PI-PDn and FOPID controllers, often struggle to manage the nonlinearities and disturbances inherent in steam condenser systems. This paper introduces a novel multistage controller, TDn(1 + PIDn), optimized using the diligent crow search algorithm (DCSA). The proposed controller is specifically designed to address system nonlinearities, external disturbances, and the complexities of dynamic responses in steam condensers. Key contributions include the development of a flexible multi-stage control framework and its optimization via DCSA to achieve enhanced stability, faster response times, and reduced steady-state errors. Simulation results demonstrate that the TDn(1 + PIDn) controller outperforms conventional control strategies, including those tuned with advanced metaheuristic algorithms, in terms of settling time, overshoot, and integral of time weighted absolute error (ITAE). This study marks a significant advancement in pressure regulation strategies, providing a robust and adaptive solution for nonlinear industrial systems.

Integration of pricing, sustainability and 3PL delivery time according to freshness date in a dual-channel fruit supply chain: A game theoretic approach

Integration of pricing, sustainability and 3PL delivery time according to freshness date in a dual-channel fruit supply chain: A game theoretic approach

Comparing the antioxidant effects of single and binary combinations of Lactiplantibacillus plantarum in vitro and in vivo and their application in yogurt.

Lactiplantibacillus plantarum (L. plantarum) have been studied for their antioxidant properties, which can mitigate oxidative stress and improve health outcomes. The study aimed to compare the antioxidant properties of single and binary L. plantarum and their impact on yogurt. L. plantarum 847 (Lp-C), L. plantarum 8014 (Lp-G), and their combination were chosen for their in vitro antioxidant potential. In vivo experiments were performed in Drosophila melanogaster (D. melanogaster) and results showed that binary L. plantarum significantly improved the survival time, weight, catalase activity and intestinal integrity in H2O2-induced flies. As compared with single L. plantarum treated flies, binary strains improved the survival curve, superoxide dismutase and catalase activities in females, prolonged the average survival time in males, and increased the expression level of keap1, Nrf2 and SOD genes in all genders. To explore the effect of single and binary L. plantarum on milk fermentation, the physicochemical properties and antioxidant activity of yogurt were detected, and results presented that yogurt fermented with L. plantarum exhibited the improved antioxidant capacity, with the binary strain combination demonstrating superior effects in rheological properties and the later period of yogurt storage. This research offers a foundation for choosing the combinations of lactic acid bacteria (LAB) with antioxidant properties.

Automated and reference methods for the calculation of left ventricular outflow tract velocity time integral or ejection fraction by non-cardiologists: a systematic review on the agreement of the two methods.

Echocardiography is crucial for evaluating patients at risk of clinical deterioration. Left ventricular ejection fraction (LVEF) and velocity time integral (VTI) aid in diagnosing shock, but bedside calculations can be time-consuming and prone to variability. Artificial intelligence technology shows promise in providing assistance to clinicians performing point-of-care echocardiography. We conducted a systematic review, utilizing a comprehensive literature search on PubMed, to evaluate the interchangeability of LVEF and/or VTI measurements obtained through automated mode as compared to the echocardiographic reference methods in non-cardiology settings, e.g., Simpson´s method (LVEF) or manual trace (VTI). Eight studies were included, four studying automated-LVEF, three automated-VTI, and one both. When reported, the feasibility of automated measurements ranged from 78.4 to 93.3%. The automated-LVEF had a mean bias ranging from 0 to 2.9% for experienced operators and from 0% to -10.2% for non-experienced ones, but in both cases, with wide limits of agreement (LoA). For the automated-VTI, the mean bias ranged between - 1.7cm and - 1.9cm. The correlation between automated and reference methods for automated-LVEF ranged between 0.63 and 0.86 for experienced and between 0.56 and 0.81 for non-experienced operators. Only one study reported a correlation between automated-VTI and manual VTI (0.86 for experienced and 0.79 for non-experienced operators). We found limited studies reporting the interchangeability of automated LVEF or VTI measurements versus a reference approach. The accuracy and precision of these automated methods should be considered within the clinical context and decision-making. Such variability could be acceptable, especially in the hands of trained operators. PROSPERO number CRD42024564868.

Effects of timely case conferencing between general practitioners and specialist palliative care services on symptom burden in patients with advanced chronic disease: results of the cluster-randomised controlled KOPAL trial

BackgroundPatients with advanced chronic non-malignant conditions often experience significant symptom burden. Therefore, overcoming barriers to interprofessional collaboration between general practitioners (GPs) and specialist palliative home care (SPHC) teams is essential to facilitate the timely integration of palliative care elements. The KOPAL trial aimed to examine the impact of case conferences between GPs and SPHC teams on symptom burden and pain in patients with advanced chronic heart failure, chronic obstructive pulmonary disease, and dementia.MethodsThe cluster-randomised controlled trial compared a structured palliative care nurse visit followed by an interprofessional case conference to usual care. Data were collected from GPs at baseline and 48 weeks, while standardised patient interviews were conducted at baseline, 6, 12, 24, and 48 weeks.ResultsWe analysed 172 patients from 49 German GP practices. Both groups showed marginal improvement in symptom burden; however, no statistically significant between-group difference was found (=-0.561, 95% CI: -3.201–2.079, p = .68). Patients with dementia experienced a significant pain reduction (=2.187, 95% CI: 0.563–3.812, p = .009). Conversely, the intervention did not have a significant effect on pain severity (=-0.711, 95% CI: -1.430 − 0.008, p=.053) or pain interference (=-0.036, 95% CI:-0.797 − 0.725, p=.926) in other patient groups.ConclusionsThe intervention showed promise in the timely introduction of palliative care elements to address pain management in patients with dementia. Further studies are needed to identify and effectively address symptom burden and pain in other patient groups.Trial registrationGerman Clinical Trials Register: https://www.drks.de/DRKS00017795 (Registration date: 9th January 2020).

Assessing the repeatability, reliability, and precision of right ventricular outflow tract and mid-pulmonary artery diameters, velocity time integrals, and agreement between site-specific stroke volumes

BackgroundRight ventricular (RV) stroke volume (SV) can be calculated via Doppler echocardiography at multiple sites in the right chambers. However, the agreement between the calculated SVs at these sites is unknown. We aimed to assess the repeatability, reliability, and precision of the distal right ventricular outflow tract diameter (RVOTD), the mid-pulmonary artery diameter (MPAD), the right ventricular outflow tract velocity time integral (VTI), and the mid-pulmonary artery velocity time integral (MPAVTI). Additionally, we evaluated the agreement between RVOTSV and MPASV.MethodsFour observers each evaluated approximately 100 patients (n = 406). Basic measurements were made over three cardiac cycles, and the repeatability, reliability, and precision of the measurements were calculated. The agreement between the two methods was presented as intraclass correlation coefficients.ResultsThe repeatability coefficient ranges for RVOTD, MPAD, RVOTVTI, and MPAVTI were 2–3 mm, 2–4 mm, 2.1–2.8 cm, and 2.4–4.1 cm, respectively. The minimal detectable change ranges for these variables were 2–4 mm, 2–5 mm, 2.2–3.0 cm, and 2.6–4.3 cm, respectively. The respective precision ranges for RVOTD, MPAD, RVOTVTI, and MPAVTI were 2.7–4.7%, 2.4–5.4%, 5.0–7.4%, and 5.4–9.2%. There were significant correlations and agreements between MPASV and RVOTSV, with the Pearson correlation coefficient ranging from 0.63 to 0.89 (P < 0.001). The intraclass correlation coefficient ranged from 0.56 to 0.89 (P < 0.001), although there was a significant bias of 1.9–11.3 mL (P < 0.001).ConclusionsThe RVOTD, MPAD, RVOTVTI, and MPAVTI measurements were repeatable, reliable, and precise. The agreement between RVOTSV and MPASV ranged from fair to excellent, although significant bias, along with a wide limit of agreement, was observed. Consequently, these methods cannot be used interchangeably.

Assessment of change in end-tidal CO2 after fluid challenge as a marker of fluid responsiveness as measured by the aortic velocity time integral in healthy anesthetized mechanically ventilated dogs.

To evaluate if variation in the end-tidal CO2 partial pressure (∆Petco2) after a fluid challenge could predict fluid responsiveness with a sensitivity of 75% and a specificity of 70% in healthy anesthetized and mechanically ventilated dogs. Diagnostic accuracy study. University hospital. Twenty-seven dogs admitted for neutering. To obtain a balanced sample between fluid responder and nonresponder dogs, a 10-mL/kg lactated Ringer's solution was administered over 15minutes to half of the population before the baseline measurements. All animals then received a fluid challenge of 10mL/kg lactated Ringer's solution in 5minutes. The velocity-time integral of aortic blood flow (VTIAo) was evaluated with Doppler echocardiography before and after a fluid challenge to classify the included dogs as fluid responders or nonresponders. Fluid responsiveness was defined as an increase of ≥15% of the VTIAo after the fluid challenge. Petco2 was evaluated at 1, 5, and 10(T1,T5,T10)minutes after fluid expansion. Area under the receiver operating characteristic curve (AUROC) analysis was used to assess the ability of ∆Petco2 to predict fluid responsiveness at different time points. A total of 13 dogs were fluid responders, and 14 were nonresponders. The best predictive capacity for ∆Petco2 was observed at T10. The AUROC with its 95% confidence interval (CI) for ∆Petco2 at T10 was 0.75 (0.56-0.93), with a sensitivity of 84.62% (95% CI, 54.60-98.10), a specificity of 64.29% (95% CI, 35.10-87.20), a positive predictive value of 68.80% (95% CI, 41.30-89.00), and a negative predictive value of 81.80% (95% CI, 48.20-97.70). The optimal cutoff was 1mmHg. The current study showed that, although minimal, ∆Petco2 predicted fluid responsiveness in the dogs studied.

Cosmological amplitudes in power-law FRW universe

The correlators of large-scale fluctuations belong to the most important observables in modern cosmology. Recently, there have been considerable efforts in analytically understanding the cosmological correlators and the related wavefunction coefficients, which we collectively call cosmological amplitudes. In this work, we provide a set of simple rules to directly write down analytical answers for arbitrary tree-level amplitudes of conformal scalars with time-dependent interactions in power-law FRW universe. With the recently proposed family-tree decomposition method, we identify an over-complete set of multivariate hypergeometric functions, called family trees, to which all tree-level conformal scalar amplitudes can be easily reduced. Our method yields series expansions and monodromies of family trees in various kinematic limits, together with a large number of functional identities. The family trees are in a sense generalizations of polylogarithms and do reduce to polylogarithmic expressions for the cubic coupling in inflationary limit. We further show that all family trees can be decomposed into linear chains by taking shuffle products of all subfamilies, with which we find simple connection between bulk time integrals and boundary energy integrals.

Reimagining Time and Narrative: Indigenous Temporalities and Social Critique in Rebecca Roanhorse’s Trail of Lightning

This paper explores how Rebecca Roanhorse’s Trail of Lightning reimagines time from an Indigenous perspective, offering a counter-narrative to the linear, clock-driven concept of time prevalent in Western thought. Through a close analysis of the novel mentioned above, the study examines Roanhorse’s integration of cyclical time, mainly through narrative techniques like flashbacks, oral storytelling, and depictions of deep time. These elements disrupt conventional linear storytelling and emphasise the interconnectedness of time, history, and the environment as seen from an Indigenous worldview.Moreover, the paper discusses how these Indigenous temporalities intersect with crucial themes in the novel, such as colonialism and environmental degradation. This intersection provides a nuanced perspective on the dystopian realities Roanhorse portrays, encouraging readers to question and rethink the dominant temporal frameworks that often contribute to environmental and social crises. By challenging these frameworks, Trail of Lightning invites us to consider a more holistic and sustainable approach to time—one that acknowledges the continuous flow of stories and events that shape our past, present, and future. In terms of methodology, the paper draws on insights from Indigenous studies scholars, including Kyle Whyte, and research from the environmental humanities to frame its analysis.

Spectral representation of cosmological correlators

Cosmological correlation functions are significantly more complex than their flat-space analogues, such as tree-level scattering amplitudes. While these amplitudes have simple analytic structure and clear factorisation properties, cosmological correlators often feature branch cuts and lack neat expressions. In this paper, we develop off-shell perturbative methods to study and compute cosmological correlators. We show that such approach not only makes the origin of the correlator singularity structure and factorisation manifest, but also renders practical analytical computations more tractable. Using a spectral representation of massive cosmological propagators that encodes particle production through a suitable iϵ prescription, we remove the need to ever perform nested time integrals as they only appear in a factorised form. This approach explicitly shows that complex correlators are constructed by gluing lower-point off-shell correlators, while performing the spectral integral sets the exchanged particles on shell. Notably, in the complex mass plane instead of energy, computing spectral integrals amounts to collecting towers of poles as the simple building blocks are meromorphic functions. We demonstrate this by deriving a new, simple, and partially resummed representation for the four-point function of conformally coupled scalars mediated by tree-level massive scalar exchange in de Sitter. Additionally, we establish cosmological largest-time equations that relate different channels on in-in branches via analytic continuation, analogous to crossing symmetry in flat space. These universal relations provide simple consistency checks and suggest that dispersive methods hold promise for developing cosmological recursion relations, further connecting techniques from modern scattering amplitudes to cosmology.

Optimal control of the gradient systems

In this paper we consider the optimal control problems governed by the gradient systems for the Ginzburg-Landau free energy where denotes a potential function and ε is the diffusivity. One example of gradient systems are the Schlögl equation arising in chemical waves with a quartic potential function F(y). Gradient systems are characterized by energy decreasing property . Numerical integrators that preserve the energy decreasing property in the discrete setting are called energy or gradient stable. It is known that the implicit Euler method is first order unconditionally energy stable method. The only second order unconditionally energy stable method is the average vector field (AVF) method. We discretize the gradients systems by discontinuous Galerkin method in space and by AVF integrator in time. We solve optimal control problems for the Schlögl equation with traveling and spiraling waves using sparse and regularized controls .

Transcriptome of the murine duodenum during recovery after a lethal dose of total body irradiation.

In the aftermath of 9/11, the radiobiology community sought novel radiation mitigators capable of preventing death when administered 24 hours or later after exposure to lethal ionizing radiation. The survival and expansion of normal stem cells are crucial for restoring tissue integrity in time to prevent mortality. While FDA-approved drugs for acute radiation syndrome primarily target the hematopoietic system, restoring the integrity of the intestinal lining is equally important for survival. However, the radiation response of the intestinal stem cell (ISC) population and its niche environment is not as well understood as that of the bone marrow. The aim of this study was to explore early transcriptomic changes in the small intestine after a lethal dose of total body irradiation (TBI), and during subsequent recovery. C3H/Sed/Kam mice were irradiated with a TBI dose of 16 Gy, the published LD 70/10 . The compound 1-[(4-Nitrophenyl)sulfonyl]-4-phenylpiperazine (NSPP) was administered 24 hours post-irradiation. RNAs from the proximal duodenum were extracted at 28, 72, and 96 hours post-irradiation and subjected to RNA-sequencing. Differentially expressed genes were analyzed using gene-set enrichment analysis. Radiation induced significant transcriptomic changes known to precede the death of lymphatic endothelial and epithelial cells. Upregulation of Lgr5+ ISC gene signature was observed during recovery. NSPP treatment further amplified the activation of ISC-associated genes and other regenerative markers. Notably, gene Psrc1 showed strong activation throughout the recovery process, highlighting its potential role in this regenerative response. These findings suggest additional points of intervention for radiation mitigation in the intestines beyond targeting programmed cell death.

Molecular Dynamics Simulation Reveals the Transport Mechanism of Molten Alkali Metal Amides

The ionic conductivity of molten LiFSA, LiFTA and LiTFSA is peculiarly lower than that of other alkali metal counterparts, where FSA = bis(fluorosulfonyl)amide, FTA = fluorosulfonyl(trifluoromethylsulfonyl)-amide, TFSA = bis(trifluoromethylsulfonyl)amide. Another peculiarity of these lithium amides is that their ionic conductivity, σ, exceeds the Nernst-Einstein conductivity, σNE, a hypothetical conductivity that would be observed if ions were moving without correlating each other. Because the correlations between ions tend to impede their movement, σ < σNE for many cases including not only molten salts, ionic liquids but also electrolyte solutions. The present molecular dynamics (MD) simulation attempts to solve these mysteries in the transport mechanism of AFSA, AFTA and ATFSA (A = Li, Na, K, Rb, Cs).We adopted the Lennard-Jones potential and the Yukawa potential (∝ exp(-κr)/r) for the intermolecular interactions of MD. The screening parameter, κ, of the Yukawa potential implicitly introduces the effect of induced polarization into the electrostatic interaction. We treated κ as an empirical parameter and determined it so as the simulated σ to reproduce the experimental results. The ionic conductivity σ was calculated by the time integral of the microscopic current correlations in the framework of the Green-Kubo formulation. The calculated σ can be divided into five terms, where the subscripts + and - stand for the cation and the anion, respectively:σ = σ+ + σ++ + σ- + σ-- + 2σ+- where σ±, σ±± and 2σ+- respectively represent the contribution to σ from the auto-correlation of each ions (σNE = σ+ + σ-), the cross-correlation between ions of the identical sign, and the cross-correlation between ions of the opposite sign.The simulation results suggest that, for K, Rb and Cs-salts, σ±± < 0, which is understandable because the ions of the identical sign repel each other to attenuate the microscopic current and hence their correlations negatively contribute to σ. However, for Li-salts, σ-- < 0, but σ++ > 0, which is the proximate cause of bringing σ > σNE. The simulation also suggests that σ- + σ-- ～ 0 for Li-salts; i.e., anions little contribute to the total conductivity as if these salts were solid electrolytes of Li. In the presentation, we will dig deeper into the issues by hypothetical questions, such as "What if Li were bigger?", "What if Li were lighter/heavier?", etc. Figure 1

Application of spaghetti knotting technology in single-hole laparoscopic suturing instructional program on the basis of multi-directional stitching technology: a randomized controlled trial

BackgroundSpaghetti knotting technology is an emerging technique that can reduce the visual field restriction of the operator in laparo-endoscopic single site (LESS) surgery. Multi-directional stitching technology has been proved to improve the accuracy of suturing in clinical application of LESS surgery. Therefore, we conducted a study to evaluate the teaching efficacy and the operation workload of spaghetti knotting technology and conventional knotting technology in LESS suture teaching based on the multi-directional stitching technology.MethodsWe selected forty junior residents to learn the skill of knot tying with single-hole laparoscopic simulators. The forty students were randomly and equally divided into control group and experimental group. The control group was trained by the conventional knotting method, and the experimental group was trained by the spaghetti knotting technology. The grades were calculated before and after the training program, including operation score of suturing time, trhead length, needle insertion accuracy, knotting stability, tissue integrity, tissue tightness and the cognitive workload score of mental, physical and temporal demands, performance, effort and frustration.ResultsThere was no significant difference between two groups before training. After training, knotting skills and workload were significantly improved. There were significant differences between the two groups in knotting time (p = 0.001), thread length (p = 0.01), and tissue integrity(p = 0.003). The experiment group took less time, left longer thread and had higher tissue integrity. The workload of the experiment group was also accurately reduced. However, there was no significant difference between the two groups in needle insertion accuracy(p = 0.560), knotting stability(p = 0.059), and tissue tightness(p = 0.731).ConclusionIn LESS suture teaching based on the multi-directional stitching technology, the training of spaghetti knotting techniques significantly improved students’ learning efficacy and reduced their workload compared to training conventional knotting techniques. It suggested the combination of spaghetti knotting and multi-directional stitching technology could be a practicable method for laparoscopic skills teaching and a feasible clinical application value on spaghetti knotting technology in LESS surgery.

Student access patterns for an online clinical skills procedural video library

ABSTRACT Clinical relevance Clinical skills training is essential in optometry curricula to develop core graduate entry competencies, including self-directed learning to facilitate life-long learning. Efficient and efficacious approaches are required to optimise student and educator time and resources. Background A video library of optometric clinical skills was created in 2012 to support self-directed student learning and face-to-face training. Use of videos in higher education generally increased during the COVID-19 pandemic and has remained above pre-pandemic levels. This study aimed to capture and evaluate student access patterns in the library to determine which videos were accessed most, and if this changed with training stage and following the pandemic. Methods Data on student viewing and critique submission were extracted for 71 videos from a clinical skills video library from 2018 to 2023. The number of videos viewed by students was analysed by year, cohort, video type (gold standard, scripted errors, summary, and student generated) and video category (history, screening, refraction, anterior segment, posterior segment and tonometry). Results First-year students viewed the most videos, and this decreased significantly during and following the pandemic. Overall, the number of videos viewed decreased with increasing course stage. Video access, by category, aligned with the curriculum. Views were highest for gold standard and student videos. Viewing of scripted error videos and submission of critiques of procedural videos was low for all course stages and years. Conclusion A web-based video library of optometric clinical skills was used for self-directed learning, mostly by students early in their training. Similar resources developed in the future should align with curriculum and include exemplar and student-based videos. Exploration of student and educator perspectives regarding factors that impact engagement with the online library warrants investigation to facilitate optimal integration in post-pandemic times.

Design of optimum spacecraft reorientation control with a combined criteria of quality based on the quaternions

Specifical original problem of attitude controlling for spacecraft was proposed in this paper. Problem of optimal rotation from a known initial state in a prescribed spatial orientation was studied in detail (turnaround time is not fixed). Design of optimal program of reorientation is based on new indicator of quality that combines energy costs including the contribution of controlling torques and integral of rotary energy (in a known proportion) and reorientation time; presence of duration factor bounds time of rotation finish. To construct an optimal control of angular momentum changing, quaternionic method and the maximum principle were applied. Differential equation that relates spacecraft angular momentum and quaternion of spacecraft orientation is a base to obtain analytic solution to a problem. We reveal the properties of optimum control program analytically, and study key features of optimum motion in details. Also, we write the formalized equations, mathematical formulas to design optimal law for change of spacecraft’s angular momentum. Analytic relations and equations are given for finding the optimal solution. Control law (in as explicit dependence between phase variables and con-trolling variables has been formulated. Main relations determining optimum values of parameters for rotation control algorithm were given. The closed-form law for rotation was obtained for dynamically symmetric solids. Numerical example as well as results of mathematical modeling of spacecraft motion that formed using optimum control are presented. This data as addition to the made theoretic descriptions shows reorientation process (in virtual form) and demonstrates practical feasibility of the developed control method. A designed algorithm for optimal control of rotation improves an efficiency of attitude system, and originates more economical performing of space vehicle during its flight along orbit.

Design of optimum spacecraft reorientation control with a combined criteria of quality based on the quaternions

Specifical original problem of attitude controlling for spacecraft was proposed in this paper. Problem of optimal rotation from a known initial state in a prescribed spatial orientation was studied in detail (turnaround time is not fixed). Design of optimal program of reorientation is based on new indicator of quality that combines energy costs including the contribution of controlling torques and integral of rotary energy (in a known proportion) and reorientation time; presence of duration factor bounds time of rotation finish. To construct an optimal control of angular momentum changing, quaternionic method and the maximum principle were applied. Differential equation that relates spacecraft angular momentum and quaternion of spacecraft orientation is a base to obtain analytic solution to a problem. We reveal the properties of optimum control program analytically, and study key features of optimum motion in details. Also, we write the formalized equations, mathematical formulas to design optimal law for change of spacecraft’s angular momentum. Analytic relations and equations are given for finding the optimal solution. Control law (in as explicit dependence between phase variables and con-trolling variables has been formulated. Main relations determining optimum values of parameters for rotation control algorithm were given. The closed-form law for rotation was obtained for dynamically symmetric solids. Numerical example as well as results of mathematical modeling of spacecraft motion that formed using optimum control are presented. This data as addition to the made theoretic descriptions shows reorientation process (in virtual form) and demonstrates practical feasibility of the developed control method. A designed algorithm for optimal control of rotation improves an efficiency of attitude system, and originates more economical performing of space vehicle during its flight along orbit.

Guiding pulmonary vasodilatory therapy in systemic sclerosis associated pulmonary hypertension using morphology of the right ventricle outflow tract velocity time integral

AbstractSystemic sclerosis (SSc) is a chronic, autoimmune disease involving small vessels characterized by skin and internal organs fibrosis. Interstitial lung disease (ILD) is one of the main findings, along with pulmonary hypertension, as a marker of morbidity and mortality. Diagnosis is usually late, and therefore treatment is established in the advanced stages of the disease. Point of care ultrasound (POCUS) emerges as a tool at the bedside for shortening diagnostic times and guiding therapy. Here, we performed a multi‐organ POCUS, evidencing the presence of ILD and pulmonary hypertension in a patient with no cardiovascular symptoms suggestive of advanced disease. We did real‐time monitoring of pulmonary vasodilator therapy at the patient's bedside using right ventricle outflow tract velocity time integral morphology (RVOT VTI). Midsystolic notching of RVOT VTI is highly specific for pulmonary hypertension. POCUS is a valuable tool that could improve diagnostic times and optimize therapy monitoring in asymptomatic patients with early manifestations of organic involvement in patients with SSc. This case demonstrates the value of POCUS as a follow‐up tool in treating patients with SSc.

Respiratory variation of velocity time integral and peak velocity of left ventricular outflow tract for predicting hypotension after induction of general anesthesia in elderly patients.

Hypotension after induction of general anesthesia may lead to severe complications in elderly patients. This study investigated whether the respiratory variation of velocity time integral (ΔVTI) and peak velocity (ΔVpeak) of left ventricular outflow tract (LVOT) could predict hypotension after induction of general anesthesia in elderly patients. 120 elderly patients undergoing selective operation under general anesthesia were enrolled in this study. ΔVTI and ΔVpeak of LVOT were measured by transthoracic echocardiography before induction of general anesthesia. After induction, mean arterial pressure (MAP) was recorded every 1 minute for 15 min. Hypotension was defined as a decrease of more than 30% in MAP at baseline or MAP below 65 mmHg from the start of induction. Receiver operating characteristic curves with gray zone and multivariate logistic regression analysis were used to assess the ability of ΔVTI and ΔVpeak of LVOT to predict hypotension after induction of general anesthesia. Hypotension occurred in 64 (53.3%) patients after induction of general anesthesia. The area under receiver operating characteristic curves (AUC) for ΔVpeak of LVOT to predict hypotension after induction of general anesthesia was 0.811, and the optimal cutoff value was 13.1% with a gray zone of 9.9% to 13.8%, including 45.0% of patients. The AUC for ΔVTI of LVOT was 0.890, and the optimal cutoff value was 13.8% with a gray zone of 11.1% to 13.9%, including 25.8% of patients. After adjusting for confounders, ΔVTI (Odds ratio = 2.24) and ΔVpeak (Odds ratio = 2.09) of LVOT were two significant independent predictors of hypotension after induction of general anesthesia. ΔVTI of LVOT was a reliable predictor of hypotension after the induction of general anesthesia in elderly patients. ΔVpeak of LVOT should be used cautiously to predict hypotension after induction of general anesthesia due to nearly half of elderly patients in the gray zone.Trial registrationThis study was registered in the Chinese Clinical Trial Registry (registration number: ChiCTR2300077117).