Time Research Articles

It’s About Time! Understanding the Dynamic Team Process-Performance Relationship Using Micro- and Macroscale Time Lenses

Although team processes are conceptualized as temporal phenomena, our theoretical understanding of their unfolding over time is underdeveloped, particularly when “zooming in and out” into their dynamics using different temporal lenses. Team processes might unfold differently over extended project cycles (i.e., macroscale time lens) versus over brief events (microscale time lens). Our goal was to better understand temporal changes of three critical higher-order team processes (i.e., transition, action, and interpersonal processes) over both extended periods (i.e., longer project cycles) and brief time spans (i.e., recurring stand-up meetings). Focusing on two agile software teams, we indexed team processes across these two time spans using computer-aided text analysis (CATA) of meeting transcripts. Macroscale time span processes were captured across 10 sprints (30-week project cycle). Microscale time spans were captured with data from brief stand-up meetings (i.e., using 10 equidistant time intervals from 40 meetings). From a macroscale time lens (i.e., project cycle), an increase in action processes in the early project phase was associated with increases in performance. From a microscale time lens, changes in transition and interpersonal processes around mid-meeting phases were associated with differences in performance. Qualitative analyses of meeting midpoints revealed key differences in proactive planning and interpersonal processes. We discuss how our results provide novel insights for team process dynamics in relation to micro- and macroscale time spans.

A Novel Medium Access Policy Based on Reinforcement Learning in Energy-Harvesting Underwater Sensor Networks.

Underwater acoustic sensor networks (UASNs) are fundamental assets to enable discovery and utilization of sub-sea environments and have attracted both academia and industry to execute long-term underwater missions. Given the heightened significance of battery dependency in underwater wireless sensor networks, our objective is to maximize the amount of harvested energy underwater by adopting the TDMA time slot scheduling approach to prolong the operational lifetime of the sensors. In this study, we considered the spatial uncertainty of underwater ambient resources to improve the utilization of available energy and examine a stochastic model for piezoelectric energy harvesting. Considering a realistic channel and environment condition, a novel multi-agent reinforcement learning algorithm is proposed. Nodes observe and learn from their choice of transmission slots based on the available energy in the underwater medium and autonomously adapt their communication slots to their energy harvesting conditions instead of relying on the cluster head. In the numerical results, we present the impact of piezoelectric energy harvesting and harvesting awareness on three lifetime metrics. We observe that energy harvesting contributes to 4% improvement in first node dead (FND), 14% improvement in half node dead (HND), and 22% improvement in last node dead (LND). Additionally, the harvesting-aware TDMA-RL method further increases HND by 17% and LND by 38%. Our results show that the proposed method improves in-cluster communication time interval utilization and outperforms traditional time slot allocation methods in terms of throughput and energy harvesting efficiency.

Negative Predictive Value of Single-Day Drug Provocation Test for Immediate and Non-Immediate Beta-Lactam Hypersensitivity Reactions in Children

Introduction: Beta-lactam antibiotics (BLAs) commonly cause hypersensitivity reactions in children. These reactions are categorized into immediate reactions, which include urticaria, angioedema, bronchospasm, and anaphylaxis, and non-immediate reactions, such as maculopapular rashes and delayed-onset urticaria/angioedema. Rashes in children, often caused by infections, may be misdiagnosed as BLA allergy. However, over 90% tolerate the medication following an allergic evaluation. Methods: We aimed to evaluate patients with negative single-day drug provocation test (sdDPT) results for subsequent reactions and to determine the negative predictive value (NPV) of sdDPT for immediate (less than 1 h) and non-immediate (more than 1 h) suspected BLA allergy. In addition, non-immediate reactions were assessed by classifying them as occurring within 1–6 h or after 6 h. Patients who underwent sdDPT for suspected BLA allergy and tested negative between 2019 and 2023 were included in the study. They were questioned via telephone interviews about their reuse of the tested drug. Results: 404 patients who underwent sdDPT for suspected BLA allergy were evaluated. The NPV of BLA sdDPT was determined to be 97.3%. When patients were categorized based on the time interval between the last dose and the reaction, the NPV was 97% for those experiencing a reaction within the first hour of drug use and 96.7% for reactions occurring after more than 1 h. Non-immediate reactions were further evaluated, revealing an NPV of 98.7% for reactions occurring between 1 and 6 h, and 92.5% for reactions occurring after 6 h. Conclusion: Our findings demonstrate that sdDPT has a high NPV for both immediate and non-immediate reactions. However, the NPV of sdDPT was lower for reactions occurring more than 6 h after the last dose.

Study of the instability of the fixed points cells temperature of working standards: establish the optimal time intervals between the comparisons

The cells of fixed freezing points of metals are an important component of the working standards of temperature of the 0th category. These standards are intended to reproduce the unit of temperature kelvin in accordance with ITS-90, which is currently the main method in the temperature range from –189 to 1084 °C. The transfer of the temperature unit is carried out by comparing the cells of the working standards of temperature with the cells of the state secondary standard of temperature. In order to develop recommendations for increasing the interval between comparisons and changing the requirements of the State Verification Scheme, one of the most important characteristics of the cells of the working standards of temperature was studied – the instability of the cell temperature in the interval between comparisons. The paper summarizes the results of the study of 26 cells of fixed points of tin, zinc and aluminum, the service life of which was from 2 to 10 years, and the interval between comparisons was from 2 to 5 years. Possible causes of instability of the reproducible temperature are described and the uncertainty of comparisons of working standard cells with secondary standard cells is calculated. The analysis of the results showed that the instability values over a long period of time do not exceed 1.02 mK for tin cells, 1.75 mK for zinc cells and 6.47 mK for aluminum cells. The most probable cause of deviation of the temperature of working standard cells from secondary standard cells is the different purity of the metals used. It is noted that the destruction of the quartz shell of the cell without mechanical action is unlikely, and the effect of pressure on the temperature of the reference point is absent. Based on the results of the comparative analysis, it was concluded that it is possible to increase the interval between comparisons for ampoules of tin and zinc to five years. Such an increase in the interval has a positive economic effect by reducing the cost of operating the state secondary temperature standard and transporting ampoules to the comparison site. For aluminum cells, an individual approach to setting the interval between comparisons is recommended based on the analysis of the results of previous comparisons. The materials published in this paper may be useful to specialists of metrological centers working with working temperature standards, as well as to all scientists studying the processes occurring in cells for measuring the solidification temperature of metals.

Is time to first CT scan in patients with isolated severe traumatic brain injury prolonged when prehospital arterial cannulation is performed? A retrospective non-inferiority study

BackgroundInvasive blood pressure measurement is the in-hospital gold standard to guide hemodynamic management and consecutively cerebral perfusion pressure in patients with traumatic brain injury (TBI). Its prehospital use is controversial since it may delay further care. The primary aim of this study was to test the hypothesis that patients with severe traumatic brain injury who receive prehospital arterial cannulation, compared to those with in-hospital cannulation, do not have a prolonged time between on-scene arrival and first computed tomography (CT) of the head by more than ten minutes.MethodsThis retrospective study included patients 18 years and older with isolated severe TBI and prehospital induction of emergency anaesthesia who received treatment in the resuscitation room of the University Hospital of Graz between January 1st, 2015, and December 31st, 2022. A Wilcoxon rank-sum test was used to test for non-inferiority (margin = ten minutes) of the time interval between on-scene arrival and first head CT.ResultsWe included data of 181 patients in the final analysis. Prehospital arterial line insertion was performed in 87 patients (48%). Median (25–75th percentile) durations between on-scene arrival and first head CT were 73 (61–92) min for prehospital arterial cannulation and 75 (60–93) min for arterial cannulation in the resuscitation room. Prehospital arterial line insertion was significantly non-inferior within a margin of ten minutes with a median difference of 1 min (95% CI − 6 to 7, p = 0.003).ConclusionTime-interval between on-scene arrival and first head CT in patients with isolated severe traumatic brain injury who received prehospital arterial cannulation was not prolonged compared to those with in-hospital cannulation. This supports early out-of-hospital arterial cannulation performed by experienced providers.

Anti-anxiety and anti-depressive effects of Thai Mucuna pruriens seed aqueous extract against ethanol withdrawal syndrome in mice

BackgroundThai Mucuna pruriens (T-MP) has been used as a traditional medicine for treating many neurological conditions due to its antioxidant and neurorestorative properties. Aim of the studyThis study was to explore the effects of T-MP seed extract on ethanol withdrawal syndrome (EWS) in mice. MethodsMice were administered either normal saline solution (NSS) or 2 g/kg of 20% ethanol intraperitoneally once daily for 10 days. Behavioral symptoms of EWS were evaluated at 12-, 24-, and 36-hours after the last dose of ethanol using the elevated plus maze (EPM), light-dark box (LDB), and tail suspension test (TST). After determining the best time interval to detect EWS, a new set of mice were induced to have EWS, at 23 h after the last ethanol dose, mice were treated with either NSS (PO), diazepam (4 mg/kg, IP), or T-MP seed extract (600 mg/kg, PO). Behavioral tests were conducted one hour after treatment. ResultsIn the ethanol withdrawal mice, anxiety- and depressive-like behavior representing EWS were seen in LDB, EPM and TST, especially at the 24-hour after the final ethanol dose. At 36-hour after the final ethanol dose, although the anxiety-like behavior could be seen in LDB and EPM, whereas no significant depressive-like in TST was observed. Treatment with DZP or T-MP could significantly reduce the anxiety- and depressive-like symptoms of EWS at 24-hour after last dose of ethanol. In addition, treatment with T-MP, but not DZP, significantly reduced the total immobility time when compared to the control ethanol withdrawal group. ConclusionAccording to this study, it was discovered that T-MP seed extract could potentially offer a beneficial effect in managing anxiety- and depression-like behaviors in EWS in mice.

Comparative Analysis of Antibacterial Efficacy and Flow Characteristics of Three Root Canal Sealers.

Oral microflora containing microorganisms is responsible for the majority of orodental diseases as well as post-endodontic treatment failure. Even in the ideal root canal treatment cases, a small number of viable bacteria will remain in the dentinal tubule hence come the role of root canal sealers, which must offer and possess some degree of antimicrobial activity alongside adequate flowability to ensure excellent sealing of all lateral dentinal tubule canals to prevent the possibility of future reinfection. The present study aimed to examine the antibacterial efficacy against Enterococcus faecalis (E. faecalis) using an agar diffusion test (ADT) at different time intervals, as well as the flow characteristics of three different root canal sealers: Endofill (Produits Dentaires SA,Vevey, Switzerland), AH Plus (Dentsply De Trey GmbH, Konstanz, Germany), and the newly introduced GuttaFlow2 (Coltène/Whaledent, Altstätten, Switzerland). The antibacterial activity and flow characteristics of three root canal sealers, Endofill, AH Plus, and GuttaFlow2, were tested using ADT at three different time intervals (24 hours, 48 hours, and seven days). For this purpose,E. faecalis strains were used as the pathogen in this study. Flow characteristics were done using the standard flow test protocol recommended for endodontic sealers. Data were analyzed using one-way ANOVA and the Tukey post hoc test, with a p-value < 0.05 considered statistically significant. The results for antibacterial activity showed a statistically significant difference between Endofill and the other groups (p < 0.05). The antibacterial activity of Endofill increased over time from 24 hours to 48 hours and seven days. AH Plus demonstrated antibacterial activity only within the first 24 hours of mixing, while GuttaFlow2 showed no inhibition zones against E. faecalis. Regarding the flow test results, the Endofill group recorded the lowest flow values compared to GuttaFlow2 and AH Plus, which was statistically significant (p < 0.05). There was no statistically significant difference between GuttaFlow2 and AH Plus for flow values. Endofill demonstrated the highest antibacterial activity at all time intervals, while GuttaFlow2 showed no antimicrobial activity. AH Plus exhibited antimicrobial effects only within the first 24 hours of mixing. In terms of flow values, Endofill had the lowest flow, whereas GuttaFlow2 and AH Plus had the highest flow values.

Investigation of SARS-CoV-2 release in fecal specimens of discharge COVID-19 patients

Abstract Objectives The presence of live SARS-CoV-2 viruses in the fecal specimens and the positive results for SARS-CoV-2 RNA in gastrointestinal samples after respiratory specimens had become negative indicate that there may be a risk of transmission of the disease not only through the respiratory tract but also through the fecal-oral route. The study aim is to determine the time period that the SARS-CoV-2 virus remains in the fecal specimens of discharged COVID-19 patients to reveal the time interval in which the risk of transmission continues. Methods In 65 patients hospitalized with a COVID-19 diagnosis, the viral RNA was isolated from the supernatant of the stool sample using CVXTM viral RNA extraction kit. The extracted RNAs from the stool samples were detected using a commercial RT-PCR method. Results Positive results were obtained in the stool samples in eight of sixty-five patients and the presence of SARS-CoV-2 in these patients was detected for up to three weeks. Conclusions By determining the residence time of SARS-CoV-2 virus in stool samples of discharged COVID-19 patients, the time interval during which the possibility of transmission risk continues has been revealed. The findings of the study could prove beneficial in comprehending the risks of transmission and translating them into preventative measures.

Cooling Uncovered Foods at a Depth of ∼5.1 cm (2 in.) or Less Poses Little Risk of Pathogen Growth

The U.S. Food and Drug Administration has guidelines for cooling cooked foods in retail operations. Data on foodborne illness risk factors in restaurants indicate that cooling is often out of compliance with these guidelines. We sought to identify factors under the control of the operator that had a significant effect on the cooling rates of cooked foods. Minneapolis Minnesota Health Inspectors were trained in standardized operating procedures for cooling data collection. Data loggers set to appropriate time intervals and calibrated to ±0.5 °C (∼1°F) were used in data collection. Analysis was performed using the R statistical computing language version 4.2.2. Preexisting pathogen models were used to predict Log CFU increases of Clostridium perfringens or Bacillus cereus. Data from 224 recipes were recorded by inspectors between October 2018 and October 2019. Food depth had a highly significant effect (p = 8.90E−08) on cooling rate. The use of an ice bath or ice wand was also significant (p < 0.005). There was a significant correlation between container material (metal or plastic) and food depth because foods with a greater depth are often being cooled in plastic containers. Foods at a depth greater than 5.1 cm (2 in.) that cooled faster than 0.23 log(°C)/h were often wholly or partially cooled in blast chillers or freezers, cooled using an ice bath or ice wand (or both), or were composed of protein pieces (e.g., chicken wings) that facilitated more rapid cooling due to air gaps in the food. Foods in shallow containers at a food depth of less than or equal to ∼5.1 cm (2 in.) that cooled more slowly than 0.23 log(°C)/h were being cooled at temperatures greater than 5 °C (41°F) or were partially or wholly covered. These foods also showed little evidence of pathogen growth from predictive models. Our analysis shows that cooling foods in shallow containers at a food depth of less than or equal to ∼5.1 cm (2 in.) poses little risk of significant pathogen growth.

Acute kidney injury as a prognostic marker in severe fever with thrombocytopenia syndrome

Severe fever with thrombocytopenia syndrome (SFTS) is a tick-borne illness with a notable morality risk that is becoming increasingly prevalent in East Asia (14–36%). Increasing evidence indicates a more direct role of the SFTS virus in renal impairment. However, few studies have explored the risk factors for and clinical outcomes of AKI in patients with SFTS. Therefore, in this study, we aimed to investigate risk factors and outcomes associated with AKI in patients with SFTS. In this retrospective cohort study, we included the data of 53 patients who were diagnosed with SFTS virus infection at Kangwon National University Hospital between 2016 and 2020. We incorporated laboratory data and medical information including comorbidities, complications, and mortality. Baseline characteristics, clinical features, laboratory parameters, and mortality rates of the non-AKI and AKI groups were compared. Patient survival of non-AKI and AKI groups were compared using the Kaplan–Meier method. To identify the population with poor prognosis, Cox regression analysis was used to identify the independent risk factors for in-hospital mortality in patients with SFTS. Of the 53 individuals, 29 (54.7%) were male, with an average age of 66.5 years. Nine patients (15.1%) died of SFTS. Twenty-seven (50.9%) patients exhibited AKI; the average time interval from fever onset to AKI occurrence was 3.6 days. Notably, 24 (88.9%) patients developed AKI within the first week of fever onset. Patients in the AKI group exhibited a significantly higher prevalence of diabetes and were older than those in the non-AKI group. The mortality rate was notably higher (29.6%) in the AKI group than in the non-AKI group (3.8%). Within the AKI cohort, advanced stages (stages 2 and 3) showed a 50% mortality rate, which was significantly higher than the 17.6% mortality rate in patients with stage 1 AKI. Additionally, Kaplan–Meier curves revealed lower survival rates among patients with AKI than among those without AKI (P = 0.017). Cox regression analysis identified leukopenia and elevated serum creatinine levels as significant risk factors for mortality. AKI is a common complication associated with SFTS. Moreover, the mortality rate was significantly higher in the patients who developed AKI than in those who did not. Our findings underscore the pivotal role of AKI as a prognostic marker of disease severity in patients with SFTS.

Association of Time Since Diagnosis of Pediatric Ileocolic Intussusception With Success of Attempted Reduction: Analysis in 1065 Patients.

BACKGROUND: Radiologists generally treat pediatric ileocolic intussusceptions emergently given potential worse outcomes from delayed reduction attempts. However, relevant literature is conflicting. OBJECTIVE: To identify factors associated with successful image-guided ileocolic intussusception reduction in children, with attention to the time interval since diagnosis. METHODS: This retrospective study included patients <6 years old who underwent attempted image-guided enema reduction of ileocolic intussusception between May 2009 and July 2023. Patients were separated into two groups: those presenting directly to the institution (nontransferred patients, who all underwent attempted reduction <8 hours after ultrasound diagnosis), and those transferred from outside facilities. EHR data were extracted. Each patient's first image-guided reduction attempt was classified as successful or unsuccessful. Univariable and multivariable analyses were performed. RESULTS: The study included 1065 patients (649 male, 416 female; mean age, 18.1 months; age range, 2.2-71.0 months; 793 nontransferred and 272 transferred patients). In nontransferred patients, the mean interval between ultrasound diagnosis and reduction attempt was 150.8 minutes; in transferred patients, the mean interval between outside facility advanced imaging and reduction attempt was 460.1 minutes (p<.001). Successful reduction occurred in 84.6% and 81.6% of nontransferred and transferred patients, respectively (p=.25). In nontransferred patients, success occurred in 85.6% of attempts <2 hours after diagnosis versus 84.0% of attempts 2-<8 hours after diagnosis (p=.54); the mean interval from diagnosis to attempted reduction was 149.7 minutes and 156.8 minutes for successful and unsuccessful attempts, respectively (p=.53). In multivariable analysis, factors showing independent associations with success were proximal intussusception location (OR=3.63, p<.001) and absence of high-risk ultrasound findings (OR=2.57, p<.001); success was not independently associated with age, sex, bloody stools, reduction method, or time since diagnosis <2 hours (p>.05). In transferred patients, the mean interval from outside advanced imaging to attempted reduction was 463.1 minutes and 440.2 minutes for successful and unsuccessful attempts, respectively (p=.74). CONCLUSION: Intussusception reduction may not require completion emergently (within 2 hours after diagnosis), but potentially may be safely performed on an urgent basis (within 8 hours). CLINICAL IMPACT: The findings have implications for determining the standard of care, including criteria for oncall activation of radiologic resources, in pediatric intussusception management.

Towards various occupants with different thermal comfort requirements: A deep reinforcement learning approach combined with a dynamic PMV model for HVAC control in buildings

Reinforcement learning (RL) has great potential in achieving energy-efficient, comfortable and intelligent control of heating, ventilation and air conditioning (HVAC) systems. Although research on RL-based HVAC control has attracted increasing interest, current studies generally use simple building simulation as the environment to train agents, and the definition of thermal comfort is limited to a wide temperature range, which cannot meet the different thermal comfort requirements of various occupants. This study proposes a deep reinforcement learning (DRL) control framework based on the Dueling Deep Q-network (DQN) algorithm, combined with a self-designed environmental model and reward function, for HVAC control meeting different thermal comfort requirements. Specifically, based on the theory of building thermal dynamics, a nonlinear equation modified by experimental data is used for the environmental model that reflects the actual thermal change of building. Different thermal comfort requirements are considered and analysed through a dynamic predicted mean vote (PMV) model that focuses on the metabolic rate and clothing level of occupants. By systematically exploring different heating modes for occupants and control time intervals, the proposed framework demonstrates that heating energy consumption can be reduced by 4.8%-39.58% under various conditions compared to rule-based control. In addition, the study found that the HVAC control based on DRL has greater potential in saving energy when the heating demand of building is higher. Our study is helpful for researchers to make HVAC control more energy-efficient and user-friendly with the help of artificial intelligence.

Cognitive functional therapy for lower back pain: A meta-analytical assessment of pain and disability outcomes in randomized controlled trials

BACKGROUND: Cognitive functional therapy (CFT) aims to address low back pain (LBP) comprehensively by considering physical, psychological, and social factors. OBJECTIVE: The objective was to evaluate the effectiveness of CFT in reducing pain and disability in individuals with LBP over various time intervals. METHOD: A comprehensive literature search was conducted to identify relevant randomized controlled trials (RCTs) assessing the effects of CFT on LBP. RESULTS: In this study, 1510 records were initially identified, and 7 studies were included in the analysis. Disability scores were significantly reduced after CFT had been applied for 6 to 8 weeks (SMD =-0.46, 95% CI [-0.74, -0.19]), 12 weeks to 3 months (SMD =-0.54, 95% CI [-0.72, -0.36]), 6 months (MD =-5.82, 95% CI [-9.82, -1.82]), and 12 months (SMD =-0.4, 95% CI [-0.55, -0.26]). There were also significant reductions in pain scores observed after 12 weeks to 3 months (SMD =-0.49, 95% CI [-0.68, -0.3]), 6 months (MD =-0.75, 95% CI [-1.5, -0.0001]), and 12 months (SMD =-0.27, 95% CI [-0.42, -0.12]). CONCLUSION: CFT showed potential for improving disability scores for individuals with LBP across various time intervals. However, its impacts on pain scores varied.

Casein phosphopeptide-amorphous calcium phosphate varnish versus dentin desensitizer in the treatment of non-carious dentin hypersensitivity

Background: Dentin hypersensitivity (DH) is one of the most common conditions clinicians encounter in clinical practice. New techniques are continuously being set forth to treat this condition. In recent times, casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) has garnered attention owing to its ability to improve remineralization and prevent enamel demineralization. Consequently, it has been indicated as an advanced treatment for DH. Purpose: This clinical trial aims to assess the efficacy of a CPP-ACP varnish in the management of non-carious cervical hypersensitivity and compare it with that of a dentin desensitizer. Methods: Patients between the ages of 20 and 65 years who reported to our institute with complaints of DH were selected for this study. Forty teeth were chosen for this study and randomly assigned to two groups. The test group was treated with a CPP-ACP varnish (MI Varnish®, GC Corporation, Japan), while the control group was treated with a dentin desensitizer (Gluma®, Heraeus-Kulzer, Germany). Dentin hypersensitivity assessments were conducted during pre-treatment, immediately following treatment, and 2 and 4 weeks after treatment. Statistical analysis was performed after data collection. Results: An intragroup comparison showed both the CPP-ACP varnish and the dentin desensitizer achieved a maximum decrease in sensitivity in the time interval from baseline to post-op, and these desensitizing effects were sustained through the second and fourth week following treatment. An intergroup comparison revealed no statistically significant difference in sensitivity between the two groups at different time intervals. Conclusion: It could be concluded that CPP-ACP varnish and dentin desensitizer possess similar efficacy in the treatment of DH.

Mechanically Induced Motor Tremors Disrupt the Perception of Time.

Contemporary research has begun to show a strong relationship between movements and the perception of time. More specifically, concurrent movements serve to both bias and enhance time estimates. To explain these effects, we recently proposed a mechanism by which movements provide a secondary channel for estimating duration that is combined optimally with sensory estimates. However, a critical test of this framework is that by introducing "noise" into movements, sensory estimates of time should similarly become noisier. To accomplish this, we had human participants move a robotic arm while estimating intervals of time in either auditory or visual modalities (n = 24, ea.). Crucially, we introduced an artificial "tremor" in the arm while subjects were moving, that varied across three levels of amplitude (1-3 N) or frequency (4-12 Hz). The results of both experiments revealed that increasing the frequency of the tremor led to noisier estimates of duration. Further, the effect of noise varied with the base precision of the interval, such that a naturally less precise timing (i.e., visual) was more influenced by the tremor than a naturally more precise modality (i.e., auditory). To explain these findings, we fit the data with a recently developed drift-diffusion model of perceptual decision-making, in which the momentary, within-trial variance was allowed to vary across conditions. Here, we found that the model could recapitulate the observed findings, further supporting the theory that movements influence perception directly. Overall, our findings support the proposed framework, and demonstrate the utility of inducing motor noise via artificial tremors.

Wavelet optical flow velocimetry of a scramjet combustor using high-speed frame-straddling focusing schlieren images

Scramjet combustors feature ultra-high-speed turbulent reacting flows with high temperatures and intense luminescence. Measurement of velocity fields under such extreme conditions presents great challenges. The present work demonstrated a seedless velocimetry approach using focusing schlieren images (FSIs) of high spatiotemporal resolution in a scramjet engine. Two fuel mass flow rates (Case1 and Case2) were investigated with corresponding global equivalence ratios of 0.27 and 0.13, respectively. The FSIs enabled by the employment of a high-speed pulsed LED light source are characterized by an effective exposure of 100 ns, and a 500-ns frame-straddling time interval with full resolution of 1280 × 800 pixels recorded at 76 kHz. The 100-ns exposure allows for capturing of transient high-speed flow motion without blurring, and the 500-ns time interval ensures an appropriate spatiotemporal correlation between subsequent schlieren images for high-speed reacting flows. A wavelet-based optical flow velocimetry (wOFV) algorithm was developed and applied to the FSIs. In contrast to the correlation-based algorithms widely employed in PIV for distinct particles, the wOFV algorithm suits better FSIs with continuous variation in brightness. The maximal velocities in the main duct of the scramjet combustor were measured to be approximately 550 m/s and 1100 m/s for Case 1 and Case2, suggestively corresponding to subsonic and supersonic combustion modes, respectively. The measured velocity inside the cavity is generally below 200 m/s for both cases. Recirculation regions and their dynamic motions inside the cavity were well resolved. In summary, the development of the novel velocimetry approach holds great potential for applications in extreme flow conditions.

Impact of an Etoposide Chemotherapy Shortage on Patients With Extensive-Stage Small-Cell Lung Cancer: Results of a Natural Experiment.

A shortage of essential intravenous (IV) etoposide lasted from 2018 until 2020 in Ontario, Canada, allowing for a natural experiment in which external factors (IV etoposide availability) dictated patients' treatment assignment. The purpose of this study was to evaluate the impact of this IV etoposide shortage (IVES) on patient care outcomes. Individuals with extensive-stage small-cell lung cancer (ES-SCLC) treated during a pre-IVES (November 2017-October 2018) and IVES (November 2018-October 2019) time intervals were retrospectively reviewed at the Verspeeten Family Cancer Centre. We investigated the association of the shortage on health care utilization and survival using a time-to-event analysis, Cox proportional hazards and logistic regression modeling. A total of 119 patients with ES-SCLC were assessed, 49 in the pre-IVES interval and 70 in the IVES interval. The median age was 68 (IQR, 62-74) years, 48% (n = 57) were male, 33% (n = 39) had CNS metastases, and 69% (n = 82) received first-line systemic therapy. Alternate regimens used for IVES cohort included IV platinum-oral (PO) etoposide, IV platinum-IV irinotecan, and PO etoposide monotherapy. An adjusted multivariable model demonstrated a significant increase in hospitalization (odds ratio, 2.30 [95% CI, 1.01 to 5.24]; P = .047) and shorter progression-free survival (PFS; hazard ratio, 1.79 [95% CI, 1.19 to 2.68]; P = .005) during the IVES. This study demonstrated increased hospitalization, and decreased PFS, among patients with ES-SCLC treated with alternate chemotherapy regimens during an IVES. The impact of cancer drug shortages can be harmful, and optimizing a more secure drug supply with mitigation strategies is warranted.

Singular limit of a chemotaxis model with indirect signal production and phenotype switching

Abstract Convergence of solutions to a partially diffusive chemotaxis system with indirect signal production and phenotype switching is shown in a two-dimensional setting when the switching rate increases to infinity, thereby providing a rigorous justification of formal computations performed in the literature. The expected limit system being the classical parabolic–parabolic Keller–Segel system, the obtained convergence is restricted to a finite time interval for general initial conditions but valid for arbitrary bounded time intervals when the mass of the initial condition is appropriately small. Furthermore, if the solution to the limit system blows up in finite time, then neither of the two phenotypes in the partially diffusive system can be uniformly bounded with respect to the L 2-norm beyond that time.

Early clearance of BK polyomavirus-DNAemia among kidney transplant recipients may lead to better graft survival.

BK polyomavirus (BKPyV)-DNAemia is a common complication in kidney transplant recipients (KTRs). The significance of achieving viral clearance at different time intervals is not well understood. All adult KTRs transplanted between January 1, 2015 and December 31, 2017 who developed BKPyV-DNAemia were included. Outcomes were analyzed based on persistent clearance of BKPyV-DNAemia at 3-month intervals up to 2 years after initial detection, and for recipients with persistent BKPyV-DNAemia at last follow-up. Uncensored graft failure, death-censored graft failure (DCGF), and a composite outcome of DCGF or fall in estimated glomerular filtration rate (eGFR) by ≥50% from the time of initial BKPyV-DNAemia were outcomes of interest. Of 224 KTRs with BKPyV-DNAemia, 58 recipients (26%) achieved viral clearance by 3 months after initial detection, 105 (47%) by 6 months, 120 (54%) by 9 months, 141 (63%) by 12 months, 155 (69%) by 15 months, 167 (75%) by 18 months, 180 (80%) by 21 months, and 193 (86%) by 24 months. Nine recipients (4%) had persistent BKPyV-DNAemia at last follow-up. Compared to recipients who achieved viral clearance by 3 months, those who achieved clearance by 6 months (adjusted odds ratio [aOR]: 3.15; 95% confidence interval [CI]: 1.22-8.12; p=.02) and 9 months (aOR: 3.69; 95% CI: 1.02-13.43; p=.04) had significantly increased risk for uncensored graft failure. There was no significant association between time to viral clearance and DCGF or composite outcomes. We found a trend of increased risk for uncensored graft failure among those who cleared BKPyV-DNAemia more slowly. Aiming to clear viremia early, without risking rejection, may be beneficial for allograft function and patient morbidity and mortality.

Persistent Lymph Node Metastases After Neoadjuvant Chemoradiotherapy for Rectal Cancer

Patients with locally advanced rectal cancer and persistent lymph node metastases (PLNM) after neoadjuvant treatment are at high risk of developing locoregional and distant metastasis, yet optimal postsurgical treatment of these patients is limited. To analyze the association of PLNM with pretreatment clinical parameters, intensity of neoadjuvant treatment, and long-term oncological outcomes. This cohort study is a post-hoc analysis of 3 randomized clinical trials (Surgical Oncology Working Group of Germany [CAO], Radiological Oncology Working Group of Germany [ARO], and Working Group for Internal Oncology in the German Cancer Society [AIO]) conducted in Germany in 1994, 2004, and 2012 that included 1948 patients with locally advanced rectal cancer recruited between February 1995 and January 2018. Statistical analysis was conducted between September 2023 and February 2024. Receiving preoperative fluorouracil-based chemoradiotherapy (CRT, comprising the preoperative group of CAO/ARO/AIO-94 and the control group of CAO/ARO/AIO-04), fluorouracil-based CRT plus oxaliplatin (experimental group of CAO/ARO/AIO-04), or total neoadjuvant treatment (TNT) with fluorouracil-based CRT plus oxaliplatin with induction or consolidation leucovorin calcium (folinic acid), fluorouracil, and oxaliplatin chemotherapy within the CAO/ARO/AIO-12 trial. The associations of PLNM with clinical parameters, intensity of neoadjuvant treatment, and cumulative incidences of LR, DM, and overall survival were assessed. A total of 1888 patients (1333 male participants [70.6%]; median [range] age, 62 [19-84] years) with locally advanced rectal adenocarcinoma (clinical tumor stage 3 to 4 and/or clinically node-positive) treated within 3 consecutive clinical trials were analyzed. A total of 522 (29%) experienced PLNM; 378 had lymph node stage (ypN) 1 (20%) after neoadjuvant treatment (ypN) 1 (20%), and 174 had ypN2 (9%). Age, clinical T-stage, N-stage, grading, carcinoembryonic antigen levels, and time interval from completion of CRT to surgery were significantly associated with PLNM, whereas sex and tumor location were not. The percentage of patients with ypN2 stage was almost halved after TNT (18 of 293 patients [6%]) compared with patients treated with fluorouracil-based CRT (114 of 1009 patients [11.3%]; χ26 = 16.693; P = .01). After a median (IQR) follow-up of 54 (37-62) months, 5-year overall survival was 86.1% (95% CI, 83.9%-88.4%) for ypN0, 74.0% (95% CI, 83.9%-88.4%) for ypN1, and 43% for ypN2 (95% CI, 35.4%-52.2%) (P < .001). The 5-year cumulative incidences of locoregional and distant metastases were, respectively, 3% (95% CI, 2.1%-4.2%) and 20% (95% CI, 18%-23%) for ypN0, 6% (95% CI, 3.4%-8.8%) and 40% (95% CI, 34%-46%) for ypN1, and 19% (95% CI, 13%-26%) and 72% (95% CI, 63%-79%) for ypN2 (both P < .001). In this cohort study, PLNM unmasked an unfavorable phenotype of rectal cancer at high risk for treatment failure. More aggressive adjuvant treatment might be considered; however, risk-adapted surveillance strategies and early recurrence-directed surgery, if feasible, are important strategies in this group of patients with CRT- and/or chemotherapy-resistant disease.