Extended Time Interval Research Articles

Abrupt conclusion of the late Miocene-early Pliocene biogenic bloom at 4.6-4.4\u2009Ma

The late Miocene-early Pliocene biogenic bloom was an extended time interval characterised by elevated ocean export productivity at numerous locations. As primary productivity is nutrient-limited at low-to-mid latitudes, this bloom has been attributed to an increase or a redistribution of available nutrients, potentially involving ocean-gateway or monsoon-related mechanisms. While the exact causal feedbacks remain debated, there is even less consensus on what caused the end of the biogenic bloom. Here, we compile Mio-Pliocene paleoproductivity proxy data from all major ocean basins to evaluate the timing and pacing of this termination. This systematic analysis reveals an abrupt and sustained reduction in low-latitude ocean productivity at 4.6–4.4 Ma. The decline in productivity coincided with a prolonged period of low orbital eccentricity and a shift towards lower-amplitude obliquity, an astronomical configuration linked to reduced East Asian Monsoon intensity and decreased riverine nutrient supply.

Nuclear-induced frequency focusing and Overhauser field distributions in periodically pumped gallium arsenide

Periodic optical pumping of semiconductor systems like gallium arsenide grants insight into the spin dynamics and coupling of electrons and nuclei. Nuclear-induced frequency focusing occurs when spin-polarized nuclei alter the Larmor spin precession frequency of the electrons to approach discrete values. These discrete values are integer or half-integer multiples of a quantity that is proportional to the repetition rate of the optical pulses. In earlier work, we presented a numerical model based on the optical Stark effect that captures the interplay of electron and nuclear spins in bulk gallium arsenide. In this paper, we report the observation of nuclear-induced frequency focusing in our material and show that this behavior can help to explain the peak deformations that we observe to persist in subsequent peaks in a magnetic-field scan measurement of Kerr rotation when the field scan is paused for an extended time interval. We demonstrate that extending our model to account for a distribution of electron spins with different Overhauser fields allows us to reproduce these observations as well as additional phenomena, including changes in Kerr rotation amplitude, from our previous work.

Corneal perforation in ocular graft-versus-host disease

PurposeCorneal perforation is a rare, vision-threatening complication of ocular graft-versus-host disease (GVHD) and is not well understood. Our objective was to examine the clinical disease course and histopathologic correlation in patients who progressed to this outcome. MethodsThis study is a retrospective case series from four academic centers in the United States. All patients received a hematopoietic stem cell transplant (HSCT) prior to developing ocular GVHD. Variables of interest included patient demographics, time interval between HSCT and ocular events, visual acuity throughout clinical course, corticosteroid and infection prophylaxis regimens at time of corneal perforation, medical/surgical interventions, and histopathology. ResultsFourteen eyes from 14 patients were analyzed. Most patients were male (86%) and Caucasian (86%), and average age at time of hematopoietic stem cell transplant was 47 years. The mean interval between hematopoietic stem cell transplant and diagnosis of ocular graft-versus-host disease was 9.5 months, and between hematopoietic stem cell transplant and corneal perforation was 37 months. Initial best-corrected visual acuity was 20/40 or better in 9 eyes, and all eyes had moderate or poor visual outcomes despite aggressive management, including corneal gluing in all patients followed by keratoplasty in 8 patients. The mean follow-up after perforation was 34 months (range 2–140 months). Oral prednisone was used prior to perforation in 11 patients (79%). On histopathology, representative specimens in the acute phase demonstrated ulcerative keratitis with perforation but minimal inflammatory cells and no microorganisms, consistent with sterile corneal “melt” in the setting of immunosuppression; and in the healed phase, filling in of the perforation site with fibrous scar. ConclusionsIn these patients, an extended time interval was identified between the diagnosis of ocular graft-versus-host disease and corneal perforation. This represents a critical window to potentially prevent this devastating outcome. Further study is required to identify those patients at greatest risk as well as to optimize prevention strategies.

Reduced Hippocampal-Striatal Interactions during Formation of Durable Episodic Memories in Aging.

Encoding of durable episodic memories requires cross-talk between the hippocampus and multiple brain regions. Changes in these hippocampal interactions could contribute to age-related declines in the ability to form memories that can be retrieved after extended time intervals. Here we tested whether hippocampal–neocortical– and subcortical functional connectivity (FC) observed during encoding of durable episodic memories differed between younger and older adults. About 48 younger (20–38 years; 25 females) and 43 older (60–80 years; 25 females) adults were scanned with fMRI while performing an associative memory encoding task. Source memory was tested ~20 min and ~6 days postencoding. Associations recalled after 20 min but later forgotten were classified as transient, whereas memories retained after long delays were classified as durable. Results demonstrated that older adults showed a reduced ability to form durable memories and reduced hippocampal–caudate FC during encoding of durable memories. There was also a positive relationship between hippocampal–caudate FC and higher memory performance among the older adults. No reliable age group differences in durable memory–encoding activity or hippocampal–neocortical connectivity were observed. These results support the classic theory of striatal alterations as one cause of cognitive decline in aging and highlight that age-related changes in episodic memory extend beyond hippocampal–neocortical connections.

Optimal Time Intervals in Two-Stage Takeover Warning Systems With Insight Into the Drivers' Neuroticism Personality.

Conditional automated driving [level 3, Society of Automotive Engineers (SAE)] requires drivers to take over the vehicle when an automated system’s failure occurs or is about to leave its operational design domain. Two-stage warning systems, which warn drivers in two steps, can be a promising method to guide drivers in preparing for the takeover. However, the proper time intervals of two-stage warning systems that allow drivers with different personalities to prepare for the takeover remain unclear. This study explored the optimal time intervals of two-stage warning systems with insights into the drivers’ neuroticism personality. A total of 32 drivers were distributed into two groups according to their self-ratings in neuroticism (high vs. low). Each driver experienced takeover under the two-stage warning systems with four time intervals (i.e., 3, 5, 7, and 9 s). The takeover performance (i.e., hands-on-steering-wheel time, takeover time, and maximum resulting acceleration) and subjective opinions (i.e., appropriateness and usefulness) for time intervals and situation awareness (SA) were recorded. The results showed that drivers in the 5-s time interval had the best takeover preparation (fast hands-on steering wheel responses and sufficient SA). Furthermore, both the 5- and 7-s time intervals resulted in more rapid takeover reactions and were rated more appropriate and useful than the 3- and 9-s time intervals. In terms of personality, drivers with high neuroticism tended to take over immediately after receiving takeover messages, at the cost of SA deficiency. In contrast, drivers with low neuroticism responded safely by judging whether they gained enough SA. We concluded that the 5-s time interval was optimal for drivers in two-stage takeover warning systems. When considering personality, drivers with low neuroticism had no strict requirements for time intervals. However, the extended time intervals were favorable for drivers with high neuroticism in developing SA. The present findings have reference implications for designers and engineers to set the time intervals of two-stage warning systems according to the neuroticism personality of drivers.

Evidence of horizontal gene transfer between land plant plastids has surprising conservation implications.

Horizontal gene transfer (HGT) is an important evolutionary mechanism because it transfers genetic material that may code for traits or functions between species or genomes. It is frequent in mitochondrial and nuclear genomes but has not been demonstrated between plastid genomes of different green land plant species. We Sanger-sequenced the nuclear internal transcribed spacers (ITS1 and 2) and the plastid rpl16 G2 intron (rpl16). In five individuals with foreign rpl16 we also sequenced atpB-rbcL and trnLUAA-trnFGAA. We discovered 14 individuals of a moss species with typical nuclear ITSs but foreign plastid rpl16 from a species of a distant lineage. None of the individuals with three plastid markers sequenced contained all foreign markers, demonstrating the transfer of plastid fragments rather than the entire plastid genome, i.e. entire plastids were not transferred. The two lineages diverged 165-185 Myr BP. The extended time interval since lineage divergence suggests that the foreign rpl16 is more likely explained by HGT than by hybridization or incomplete lineage sorting. We provide the first conclusive evidence of interspecific plastid-to-plastid HGT among land plants. Two aspects are critical: it occurred at several localities during the massive colonization of recently disturbed open habitats that were created by large-scale liming as a freshwater biodiversity conservation measure; and it involved mosses whose unique life cycle includes spores that first develop a filamentous protonema phase. We hypothesize that gene transfer is facilitated when protonema filaments of different species intermix intimately when colonizing disturbed early succession habitats.

Maximising the acceptability of extended time intervals between screens in the NHS Cervical Screening Programme: An online experimental study.

ObjectiveThe NHS Cervical Screening Programme plans to increase the screening interval from 3 to 5 years for women aged 25–49 who test negative for human papillomavirus (HPV). This exploratory cross-sectional online survey tested the impact of different levels of information about the proposed change on acceptability of a longer interval.MethodsWomen aged 18–45 (n = 585) were individually randomised to one of three information exposure groups differing in the level of information provided about the screening interval change: (1) basic information; (2) basic information with additional detail about timeline of HPV infection; (3) as (2) but with the addition of a diagram. Acceptability of the change (favourable and unfavourable attitudes) was assessed post-exposure alongside HPV timeline beliefs. We used ANOVA and regression analyses to test for between-group differences.ResultsWomen in Group 3 had higher scores on the favourable attitudes sub-scale compared with Group 1. Women in Groups 2 and 3 had more accurate timeline beliefs than those in Group 1. There were no between-group differences in unfavourable attitudes. After adjusting for demographic factors, a higher favourable attitudes score was independently predicted by being in Group 3 compared to Group 1, more accurate HPV timeline beliefs, and previous irregular or non-attendance at screening.ConclusionsOverall, acceptability of an increased screening interval was moderate, but providing women with information about the safety and rationale for this change may improve acceptability. In particular, communicating the long timeline from HPV exposure to cervical cancer may reassure women about the safety of the proposed changes.

Treatment of partial thickness burns of the face with Acticoat7™ : Aretrospective single center study.

SummaryBackgroundThe face is affected in more than 50% of patients with extensive burn trauma. Effective treatment is of importance to avoid hypertrophic scarring, functional impairment and social stigmatization.Material and methodsAll patients treated with Acticoat7™ due to superficial and deep partial thickness burns of the face between 2008 and 2017 at the intensive care unit (ICU) for burn trauma at the Department for Plastic and Reconstructive Surgery of the Medical University of Vienna were retrospectively analyzed. Patients were evaluated for the number of required dressing changes until complete re-epithelialization, bacterial colonization, potential complications and the need for primary and secondary surgery.ResultsA total of 100 patients were analyzed. It took a median dressing change rate of 1 (range 0–5) in the superficial partial thickness and 3 (range 1–11) in the deep partial thickness group. Conservative treatment of deep partial thickness wounds was possible in 79% and 17% of these patients required secondary scar revision. Although bacterial colonization of the wounds frequently occurred, wound infections were rarely observed.ConclusionActicoat7™ is a valuable dressing for treating superficial and deep partial thickness burn wounds of the face in an intensive care unit setting. It enables extended time intervals between dressing changes without an increased risk for complications.

The role of ambulatory 24-hour esophageal manometry in clinical practice.

High‐resolution manometry revolutionized the assessment of esophageal motility disorders and upgraded the classification through the Chicago Classification. A known disadvantage of standard HRM, however, is the inability to record esophageal motility function for an extended time interval; therefore, it represents only a more snapshot view of esophageal motor function. In contrast, ambulatory esophageal manometry measures esophageal motility over a prolonged period and detects motor activity during the entire circadian cycle. Furthermore, ambulatory manometry has the ability to measure temporal correlations between symptoms and motor events. This article aimed to review the clinical implications of ambulatory esophageal manometry for various symptoms, covering literature on the manometry catheter, interpretation of findings, and relevance in clinical practice specific to the evaluation of non‐cardiac chest pain, chronic cough, and rumination syndrome.

Prospective observational evaluation of radiation-induced late taste impairment kinetics in oropharyngeal cancer patients: Potential for improvement over time?

Background and purposeTaste impairment is a common radiation-induced toxicity in head and neck cancer (HNC) patients acutely. However, data on the potential for recovery and the time dependent course of late taste impairment are limited. Materials and methodsAs part of an IRB-approved observational prospective study, HNC patients underwent serial surveys including the MD Anderson Symptom Inventory - Head and Neck module (MDASI-HN). For our analysis, we extracted MDASI-HN taste item results from oropharyngeal cancer patients treated with intensity-modulated radiotherapy or volumetric modulated arc therapy and at least two taste assessments after ≥1 year from end of radiotherapy (RT). Results1214 MDASI taste items from 326 patients between 1 and 13 years post-RT were included. Median prescribed dose to the high-dose clinical target volume (CTV1) was 66.0 Gy, with 180 patients (55%) receiving chemotherapy. Taste markedly improved in the first years from end of RT, but plateaued after year 5. In patients with taste assessment in subsequent years, a significant reduction in taste impairment was found from the second to the third year (p = 0.001) and tended towards significance from the third to the fourth year (p = 0.058). Multivariate analysis revealed treatment site as significant factor in the sixth year from RT and CTV1 dose and age in the seventh year. ConclusionRadiation-induced taste impairment may improve over an extended time interval, but becomes relatively stable from year 5 post-RT. Direct characterization of RT-induced taste impairment and the calculation of normal tissue complication probability should include consideration of the time-dependent course in taste recovery.

Effect of pessary cleaning and optimal time interval for follow-up: a prospective cohort study

Introduction and hypothesisThe objective of this study was to determine the efficacy of routine follow-up visits for pessary cleaning, the effect of extended time intervals between visits and the proportion of patients being able to self-manage their pessary for pelvic organ prolapse (POP).MethodsWe conducted a prospective cohort study in patients with a stage ≥II POP without previous POP surgery. All patients received a pessary as primary treatment. Our main outcome measure was a difference ≥2 in median visual analogue scale (VAS) scores (for pain, discharge, irritation) 1 week before and 1 week after cleaning. Measurements were performed after 3- and 9-month cleaning intervals. For the evaluation of the effect of cleaning, 132 patients (3 months’ follow-up) and 87 patients (12 months’ follow-up) were available for analysis. For the evaluation of the effect of the lengthening interval, 123 patients were available.ResultsSelf-management was performed in 45.2% of patients at 1 year. In 93.1% of patients, no differences were observed in pre-and post-cleaning VAS scores (effect of cleaning) on vaginal pain. Nor was there a difference in discharge (72.4%) or irritation 85.1% (p = 0.00). No differences were observed in pre-cleaning VAS scores for vaginal pain, discharge and irritation when the interval was lengthened from 3 to 9 months. No serious adverse events occurred.ConclusionsThere is no proven benefit of regular follow-up visits to clean a pessary. Also, the length of the cleaning interval does not seem to matter.

Delayed interval delivery (DID) with raised markers of infection and emergency cervical cerclage − a case report and review of literature

Typically, all fetuses of a multiple gestations deliver within a short interval; however, in selected cases, the preterm birth of one fetus may not require delivery of the other fetus (es). An extended time interval between births of siblings at a critical gestational age may improve neonatal survival and reduce morbidity from preterm birth. We report a case of 41year old woman with twin IVF pregnancy, in which the first twin delivered at 22 weeks and the second twin was delivered at 31 weeks with a favourable outcome. Conclusion: With the increasing use of ART and consequent multifetal gestation, premature delivery is the most dreaded complication with the loss of all babies. In recent years the approach to the fate of after coming twins during preterm delivery has changed. Desperate attempts to salvage the second twin by delaying delivery have been reported recently in some cases with favourable outcome for the second twin.

A moderately extended time interval between hCG administration and oocyte retrieval is good for most patients with oocyte retrieval scheduled on the same day: a retrospective cohort study

Evidence is limited regarding the time intervals between human chorionic gonadotropin (hCG) administration and oocyte retrieval in controlled ovarian hyperstimulation cycles, and it is difficult to determine proper schedules to optimise outcomes for patients undergoing oocyte retrieval on the same day. We aimed to identify correlations between factors pertaining to treatment outcomes and time intervals to facilitate working schedules of ART centres. Our study included 2509 patients who underwent ICSI cycles. Based on different time intervals between hCG administration and oocyte retrieval, all cycles were divided into four groups: group 1 (34.00–35.99 hours), group 2 (36.00–36.99 hours), group 3 (37.00–37.99 hours) and group 4 (38.00–39.32 hours). Female age, basal FSH level, Gn starting stimulation dosage and total Gn dosage of group 1 were significantly higher than those of other groups. E2 level on hCG day and number of follicles aspirated were significantly higher in group 4 than in the other groups. Number of oocytes retrieved, oocyte retrieval rate, cleavage rate and number of usable embryos were positively correlated with the time interval, even after adjusting for female age, basal FSH level, E2 on hCG day and number of follicles aspirated. A fixed hCG administration time matching arranged oocyte retrieval is good enough for most patients to achieve maximal treatment outcomes. For patients with lower treatment expectations (expected no. of oocyte retrieval ≤3), moderately delayed oocyte retrieval would be more appropriate. Impact Statement What is already known on this subject? The time interval between hCG administration and OPU during COH is essential for ART treatment outcomes, but different intervals were reported in previous studies. What the results of this study add? Fixed hCG administration time matching arranged OPU is good enough for most patients to achieve maximal outcomes. For patients with lower treatment expectations (expected no. of oocyte retrieval ≤3), moderately delayed oocyte retrieval would be required. What the implications are of these findings for clinical practice and/or further research? We studied whether the oocytes and pregnancy outcomes changed along with extended time intervals, and there is no need to adhere to an exact interval for every patient. Therefore, it would help clinicians develop more reasonable time schedules for fertility centres and patients undergoing oocyte recovery on the same day.

Economic convergence in the EU and Eurozone

Purpose The purpose of this paper is to analyse whether several groups of European countries are on track for real “conditional” economic convergence in per capita income and the likely speed of convergence. The paper focusses also on the changes of the convergence processes over time. Design/methodology/approach Unlike the simple “absolute convergence”, it explores the concept of “conditional” or “club” convergence. Moreover, it adopts the approach of extending the univariate model to take into account the panel dimension over an extended time interval and endogeneity. Findings A process of real economic convergence has characterised the period under investigation (1995–2016), but, in general, the size and significance of the parameter is greater for the wide European Union (EU) area (EU25 and above) rather than the Eurozone (EZ). However, the crises occurred after 2008 caused most of such lower convergence in the Euro area. Research limitations/implications This paper gives an estimate of the speed/time needed to several groups of European countries (EZ, in particular) to achieve real economic convergence. Future research could further develop the “stochastic” convergence concept. Originality/value This is an analysis of convergence in enlarging EU and EZ for an extended period (including the big crisis period and the subsequent recovery). It shows that EZ experienced a drop in the speed of real convergence after 2008 and converge at lower speed than the EU. As a consequence, a specific budget for EZ would be important to provide adjustment mechanisms after potentially large shocks.

445P - Safety and feasibility of extending flushing interval every 3 months for maintenance of TICVPS in CRC patients after completion of curative intended treatments

BackgroundColorectal cancer (CRC) patients treated with curative intended surgery undergo 5-FU continuous infusion based chemotherapy using totally implantable central venous port system (TICVPS) in case of high-risk of recurrence. Approximately 30% patients relapse after the completion of therapy, especially within 2 years. Hence, many of high-risk CRC patients keep the TICVPS during 6-24 months after treatment, with regular intervals of TICVPS flushing. The manufacturer recommends monthly flushing for maintain TICVPS, however the interval of flushing lacks scientific evidence. The aim of this study is to investigate whether the extended maintenance intervals is safe and feasible. MethodsA retrospective cohort was conducted in CRC patients who underwent curative intended surgery and perioperative chemotherapy using TICVPS between 2010 and 2017. Patient were enrolled if TICVPS was maintained at least 6 months with 3-month interval flushing using heparin, while patient who were recurred within 1 month, removed TICVPS within 6 months without definitive causes, or violation of flushing interval were excluded. The primary end points were the functional TICVPS maintenance rate. ResultsA total of 214 CRC patients underwent curative intended treatments during the study period. Among them, 6 patients (early recurrence within 1 month) and 54 patients (violation of flushing interval) were excluded, finally 154 patients were analyzed. Mean flushing interval was 98.4 days. At the Dec 2018, 35 patients kept the TICVPS, 92 were planned removal, and 25 were reused the TICVPS, while two patients had to unexpectedly remove due to TICVPS site infection and pain. Thus, the functional TICVPS maintenance rate was 98.8%. 38 patients were relapsed and 30 were treated with intravenous chemotherapy. Among them, 25 patients (83.3%) were reused the existing TICVPS without re-insertion procedure. ConclusionsOur study demonstrated that 3-month interval flushing is safe and feasible in CRC patients. Extended time interval up to 3 months might be considered because it is compatible with CRC surveillance visit schedules and convenient for patients. Legal entity responsible for the studyThe authors. FundingHas not received any funding. DisclosureAll authors have declared no conflicts of interest.

Extended time interval between diagnosis and surgery does not improve the outcome in patients operated for resection or ablation of breast cancer liver metastases

BackgroundBreast cancer liver metastases (BCLM) is considered a systemic disease with poorly defined selection criteria for surgery and little evidence for the appropriate timing of surgery. MethodsPostoperative outcomes of patients operated for BCLM were retrospectively reviewed and compared based on the timing of surgery, with the early surgery (ES) group treated ≤12 months after BCLM diagnosis, and late surgery (LS) group operated >12 months after diagnosis. ResultsSeventy-two patients with BCLM underwent liver surgery, including 37 and 35 in the ES and LS groups, respectively. Demographic and preoperative characteristics were similar between the groups, except that multifocal liver disease was more frequent in the LS group (p = 0.008). The LS group had a morbidity rate of 38%, compared to 11% in the ES group (p = 0.015). No postoperative deaths occurred. In the whole cohort, median progression-free (PFS) and overall survival (OS) were 19 and 50 months, respectively, and 1-, 3- and 5-year PFS and OS were 63%, 41%, 24% and 93%, 66%, 43%, respectively, with no significant difference observed between the ES and LS groups. Multivariate analysis revealed that breast cancer progesterone receptor negativity (HR = 3.34, p = 0.03) and a size of LM > 40 mm (HR = 3.11, p = 0.01) were significant negative prognostic factors for PFS. Only a size of LM > 40 mm (HR = 2.79, p = 0.008) was significantly associated with shorter OS. ConclusionA prolonged preoperative observational period does not improve long-term outcomes after liver surgery in patients with resectable BCLM, suggesting that early management can safely be proposed to those patients, with good oncological outcomes.

Квазисинонимические уступительные конструкции в бурятском языке

Introduction. The syntax of the complex sentence in Altaic languages is characterized by a large number of synonymous constructions. Goals. The paper seeks to differentiate the synonymous constructions, firstly, to systemically identify important oppositions and, secondly, to determine development vectors of certain constructions. The study hypothesizes such constructions as actually quasi-synonymous, i.e. those are not complete synonyms and differ in shades of meaning or style. For the first time in Mongolian studies, the paper attempts to differentiate quasi-synonymous poly-predicative constructions with concessive meanings. In modern Buryat, concessive-adversative relations are expressed by four structurally different constructions, namely: ones containing adverbial participles ending with –bashye (-бАшье), ones with the particles γaa and -shye (hаа, -шье), ones with the concessive-adversative particle aad (аад), and ones containing the bifinite construction with particles on the basis of the service verb of saying –ge (гэ-). The study investigates examples from Buryat imaginative literature placed in the online Buryat corpus. Methods and results. The use of methods of contextual analysis, introspection and linguistic experiment makes it possible to identify various semantic shades, such as principal mono-subjectivity, an extended time interval between events, and a complication with the modus component. Thus, the differentiation of quasi-synonymous constructions contributes to the refinement and rationing of relations between them.

Aging and rejuvenation during elastostatic loading of amorphous alloys: A molecular dynamics simulation study

Using molecular dynamics simulations, we investigate the effect of uniaxial elastostatic compression on the potential energy, structural relaxation, and mechanical properties of binary glasses. We consider the three-dimensional Kob-Andersen binary mixture, which was initially cooled from the liquid state to the glass phase with a slow rate at zero pressure. The glass was then loaded with a static stress at the annealing temperature during extended time intervals. It is found that the static stress below the yielding point induces large-scale plastic deformation and significant rejuvenation when the annealing temperature is smaller than a fraction of the glass transition temperature. By contrast, aging effects become dominant at sufficiently small values of the static stress and higher annealing temperatures. The mechanical tests after the elastostatic compression have shown that both the elastic modulus and the yield stress decrease in rejuvenated samples, while the opposite trend was observed for relaxed glasses. These results might be useful for the thermomechanical processing of metallic glasses with optimized mechanical properties.

LO76: Impact of high emergency department occupancy on time to physician initial assessment: a traffic theory analysis

Introduction: Emergency department (ED) congestion is an ongoing threat to quality care. Traditional measures of ED efficiency use census and wait times over extended time intervals (e.g. per year, per day), failing to capture the hourly variations in ED flow. Borrowing from the traffic theory framework used to describe cars on a freeway, ED flow can instead be characterized by three fundamental parameters: flux (patients traversing a care segment per unit time), density (patients in a care segment per unit time), and duration (length of stay in a care segment). This method allows for the calculation of near-instantaneous ED flux and density. To illustrate, we examined the association between stretcher occupancy and time to physician initial assessment (PIA), seeking to identify thresholds where flux and PIA deteriorate. Methods: We used administrative data as reported to government agencies for 115,559 ED visits from April 1, 2014 to March 31, 2016 at a tertiary academic hospital. Time stamps collected at triage, PIA, and departure were verified by nosologists and used to define two care segments: awaiting assessment or receiving care. Using open-source software developed in-house, we calculated flow measures for each segment at 90-minute intervals. Graphical analysis was supplemented by regression analysis, examining PIA times of high (CTAS 1-3) or low (CTAS 4-5) acuity patients against ED occupancy (=density/staffed stretchers) adjusting for the day of the week, season and fiscal year. Results: At occupancy levels below 50%, PIA times remain stable and flux increases with density, reflecting free flow. Beyond 50% occupancy, PIA times increase linearly and flux plateaus, indicating congestion. While PIA times further deteriorate above 100% occupancy, flow is maintained, reflecting care delivery in non-traditional spaces (e.g. hallways). An inflection point where flux decreased with increased crowding was not identified, despite lengthening queues. Conclusion: The operational performance of a modern ED can be captured and visualized using techniques borrowed from the analysis of vehicular traffic. Unlike cars on a jammed roadway, patients behave more like a compressible fluid and ED care continues despite high degrees of crowding. Nevertheless, congestion begins well below 100% occupancy, presumably reflecting the need for stretcher turnover and saturation in subsegmental work processes. This methodology shows promise to analyze and mitigate the many factors contributing to ED crowding.

Development and Characterization of Liposome-Enriched Ketoprofen Liposomal Hydrogels

The purpose of this study was to develop liposome-enriched Ketoprofen liposomal hydrogels and carry out in vitro release profile experiment. The aim was to achieve sustained topical drug delivery for extended time interval from liposomal gels. Phosphatidylcholine, Cholesterol and Ketoprofen were dissolved in chloroform/methanol (2:1, v/v) mixture and subsequently transferred to a flask attached to rotavapor. The liposomes were assessed for particle size and percent drug entrapment. F-7 and F-8 batches were found to be optimized batches having optimum sizes, drug entrapment efficiencies and cumulative drug releases. F-8 batch was further evaluated for stability. The results show that the prepared liposomes of Ketoprofen might turn out to be potential candidates for effective and safe sustained drug delivery thereby resulting in the reduction of dosing frequency.